DE29904028U1 - Safety spindle head for spindle drives - Google Patents

Description

NEYMEYER & PARTNER GbR, Patent Attorneys J !***·.! I *··*··■ *··&)52 Villingen-Schwenningen (DE)

MN / win ····· ··.· ···· 03 March 1999

Applicant ref.: K

Applicant: Klann Tools Ltd., Didcot, Oxfordshire OX 11 7PL, GB Applicant No.: 8635978

Designation: Safety spindle head for spindle drives Description

The invention relates to a spindle drive, in particular for spring tensioners, with a threaded spindle having a spindle head and a threaded portion, which has a drive element for actuating the threaded spindle, which drive element is connected as a separate component to the spindle head in a rotationally fixed manner by at least one coupling pin, wherein the threaded spindle is rotatably mounted in a guide tube via at least one axial thrust bearing.

A spindle drive of the generic type is known (DE 93 19 183 Ul), in which a threaded spindle is used for the axial adjustment of clamping jaws of a spring tensioner. The threaded spindle is rotatably mounted in a head part of a cylindrical guide tube by means of an axial thrust bearing and is supported axially on the axial thrust bearing via an axial thrust ring. The clamping jaws serve to accommodate one spring coil of a helical spring to be tensioned. To rotate the threaded spindle when tensioning and relaxing the helical spring,

K230.doc

NEYMEYER & PARTNER GBR, Patent Attorneys I ·"**··! · *··*··· * · &idigr;&)52 VUlingen-Schwenningen (DE)

MN/win ····· ·· ·* ·· ·· 03 March 1999

spring, this is provided on the head part with a separate drive element in the form of a drive hexagon that protrudes beyond the head part and is mounted on a spindle head of the threaded spindle in a rotationally fixed manner by means of a coupling pin. The first clamping claw is fixed to one end of the guide tube, while the second clamping claw is coupled to a spindle nut so that it can be moved axially along the guide tube. By turning the threaded spindle, the clamping claw on the spindle nut side is moved together with the spindle nut towards the first clamping claw so that the coil spring clamped between the clamping claws is compressed. During the clamping process, the guide tube of the spring tensioner lies together with the threaded spindle outside the coil spring.

The coupling pin, by means of which the drive hexagon is fixed to the spindle head in a rotationally fixed manner, serves as an overload protection for the threaded spindle. The coupling pin is sheared off when the coil spring is compressed to the block and the threaded spindle is still rotated. After the coupling pin is sheared off, the torque connection between the drive hexagon and the threaded spindle is removed, so that no more actuating torque can be transmitted and thus damage to the threaded spindle is prevented by

K230.doc

NEYMEYER &PARTISER GBR, Patent Attorneys JJ*". . J I *.. * ♦ . &Idigr;" . &Idigr;&52 VüBngen-Schwenningen (DE)

MN/win *··*···" *··* ·· ·· ·· 03 March 1999

Overload is excluded. Since the coil spring is tensioned to the block in the described case, the spring tensioner
usually together with the coil spring
from the corresponding spring mounts of the vehicle. This makes it possible to replace the coupling pin located outside the guide tube with a new one, so that the spring tensioner can be
is operational.

The coupling pin can also shear off if the

Coil spring is not yet tensioned on block. This
can occur especially when an impact wrench is used to operate the spring compressor. In this case, the not fully tensioned coil spring together with the spring compressor cannot be removed from the spring mounts on the vehicle. In order to

In order to be able to release the spring tension again and remove it from the coil spring, the threaded spindle of the spindle drive of the known spring tensioner is provided with an additional drive element with at least one wrench flat, which is integrally formed on the spindle head.
This additional drive element can now be used to operate the threaded spindle using an appropriate key tool, so that the spring compressor can be removed from the coil spring for repair.

Therefore, there is always at least a second key

K230.doc

NEYMEYER & PARTNER GBR, Patent Attorneys J &idigr; ***. . &Idigr; I *·· *··· *·&idigr;4)52 Villingen-Schwenningen (DE)

MN /win *··*···*"··**··" ···· 03 March 1999

tool is necessary to operate this well-known spindle drive.

Another spindle drive of the generic type (DE 296 12 001 Ul) has become known, which is also intended for spring tensioners for tensioning coil springs. The spindle drive also has a threaded spindle which is rotatably mounted in a guide tube via at least one axial thrust bearing. To actuate the threaded spindle, a drive element in the form of a separate drive hexagon is provided, which is connected in a rotationally fixed manner to the spindle head of the threaded spindle via a coupling pin. The coupling pin, by means of which the drive hexagon is rotationally fixed to the spindle head, also serves as an overload protection for the threaded spindle. For axial support on the axial thrust bearing, the threaded spindle is provided with an axial thrust ring, which is axially fixed as a separate component on the threaded spindle via a locking pin and/or a threaded connection. The spindle drive of this known spring tensioner also has an additional drive element with at least one key flat to its drive hexagon, which can be designed in different ways. On the one hand, a drive element is provided which is an integral part of the threaded spindle and in the form of an external hexagon.

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys I &idigr; ***· · &idigr; · *·♦ *··· *·&idigr;&iacgr;&dgr;)52 VUtingen-Schwenningen (DE)

MN/win *·«*.·.* *··**··* ··* ·· O3.Märzl999

edge or a hexagon socket can be arranged at one or both ends of the threaded spindle. Furthermore, wrench surfaces can also be provided on the axial pressure ring, which ensure that the threaded spindle and thus the spring tensioner can be operated if the coupling pin between the drive hexagon and the threaded spindle shears off. In particular, the spring tensioner can also be released again here if the torque connection between the drive hexagon and the threaded spindle is eliminated by the coupling pin breaking or shearing off. The threaded spindle of the spring tensioner is also operated manually using a wrench tool when the drive element is removed or after the coupling pin has broken. Due to the limited accessibility, particularly when using the spring tensioner on a motor vehicle, it may be necessary to remove the drive element before a wrench tool can be placed on the wrench surfaces of the axial pressure ring. In addition, a second tool specially adapted to the arrangement and design of the wrench surfaces is always necessary.

Accordingly, the invention is based on the object of designing a spindle drive of the generic type in such a way that, after the rotationally fixed connection between

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J J ***· · J &idigr; *·· *··· *·?&iacgr;&52 VUlingen-Schwenningen (DE)

MN /win ".."..." "..""..* ..*.. March 3, 1999

the drive element and the spindle head of the threaded spindle is eliminated by the coupling pin, the threaded spindle can be brought back into a safe operating state with little effort to relax a coil spring clamped in a spring compressor.

The object is achieved according to the invention in that the drive element and/or the threaded spindle is/are provided with one or more coupling parts, via which the drive element and the threaded spindle can be brought into a frictional or positive, rotationally fixed connection after the connection between the drive element and the spindle head caused by the coupling pin has been canceled by carrying out an axial movement of the drive element relative to the threaded spindle.

The design according to the invention provides a spindle drive, in particular for spring tensioners, which is characterized by extremely simple handling and extremely high operational reliability. The spindle drive has a drive element which is connected as a separate component to the spindle head in a rotationally fixed manner by a coupling pin. In order to be able to continue operating the threaded spindle after shearing off this rotary connection between this drive element and the spindle head and thus the threaded spindle,

K230.doc

Neymeyer & PARTNER GbR, Patent Attorneys I i ***··! * *··*··· *«lä)52 Vilüngen-SchneiiningenCDE)

MN/win ·« ··· ·· ·· ·· ·· 03. March 1999

In particular, in order to be able to relax a coil spring clamped in a spring tensioner, the drive element can be moved axially relative to the threaded spindle when the coupling pin has been sheared off on the spindle head. The drive element or the threaded spindle or the drive element and the threaded spindle are provided with one or more coupling parts which can be brought into a rotationally fixed connection by friction or positive locking by carrying out this axial movement of the drive element relative to the threaded spindle. This design of the spindle drive according to the invention makes it extremely easy to handle. No additional key tool is required to continue operating the spindle drive after the coupling pin has broken. All that is required is to move the drive element, which is normally intended to operate the spindle drive when the coupling pin is intact, axially on the spindle head in order to create a rotationally fixed connection between the spindle head, i.e. the threaded spindle and the drive element. This axial movement can be easily achieved by applying pressure to the drive element, whereby the key tool originally intended for the drive element can remain on it.

K230.doc

Neymeyer & PARTNER GbR, Patent Attorneys JI * ^# * « · i * *··*··'* tlä)52 VüBngen-Schwenningen (DE)

MN /win *··*...* ·· ·· ·· ·· 03 March 1999

In order to be able to achieve a frictional connection between the drive element and the spindle head, for example, the drive element or the spindle head has a truncated cone-shaped cone section as a coupling part, which runs coaxially to the drive element or the spindle head and with which the drive element can be brought into clamping connection with the threaded spindle by the axial movement. According to claim 2, this cone section can be part of a central receiving bore which is arranged either in the drive element or in the spindle head. In this alternative embodiment, the drive element can be plugged onto the spindle head with axial play so that an axial movement can be carried out relative to the threaded spindle or the spindle head. As a result of the cone section, the drive element comes into clamping contact with the spindle head with the cone section of its central receiving bore when the axial movement is carried out. This clamping connection in turn creates a non-rotatable frictional connection between the drive element and the spindle head, which means that the threaded spindle can be operated safely via the drive element even if the coupling pin is broken. Alternatively, the mounting hole can also be arranged on the front side of the spindle head, in which case the drive element has a plug pin

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys I &iacgr; ***· « &iacgr; I *·· *··&idigr; * .38052 Villingen-Schwenningen (DE)

MN/win *··*···" *·· ·· ·· ·· 03 March 1999

with which it can be inserted into this receiving bore of the spindle head with axial play. In this alternative, the receiving bore of the spindle head has the truncated cone-shaped cone section arranged coaxially to the receiving bore, so that when the drive element moves axially relative to the spindle head into this receiving bore of the spindle head, a clamping connection is achieved via the cone section of the receiving bore and the plug pin of the drive element. Thus, in the second alternative, a rotationally fixed connection between the drive element and the spindle head and thus the threaded spindle can be achieved in the simplest way by simply axially moving the drive element relative to the spindle head. As already mentioned above, the same tool that is normally used to operate the threaded spindle when the coupling pin is intact can still be used.

According to claim 3, however, the spindle head of the threaded spindle or the plug pin of the drive element, depending on the design of these components, can also be provided with a truncated cone-shaped cone section tapering towards the drive side, which can then be clamped into a rotationally fixed connection with a part of the receiving bore of the drive element or correspondingly the spindle head by carrying out the axial movement.

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J &iacgr; ***··· J *··*···* ·3Φ52 VUlingen-Schwenningen (DE)

MN/win *.·*...* *··**.·* ··* ··* 03 March 1999

Thus, the design according to claim 3 also allows the spindle drive to continue to be operated in a very simple manner in the event that the coupling pin between the drive element and the spindle head is broken.

According to claim 4, both the receiving bore and the spindle head or the plug pin, depending on the design of the drive element or the spindle head, can each have a truncated cone section, which can be brought into mutually clamping connection by the axial movement.

This design achieves a larger friction surface and thus a secure frictional connection when carrying out the axial movement between the drive element and the spindle head or the threaded spindle.

According to claim 5, an axial pressure ring can also be used to achieve the frictional, rotationally fixed connection between the threaded spindle and the drive element, via which the threaded spindle is supported on the axial pressure bearing for axial support. This axial pressure ring is connected to the threaded spindle in a rotationally fixed manner.

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J J *"" · « &idigr; « *··*···* •'58^52 Villingen-Schwenningen (DE)

MN/win "··*...* ".·**#." ··* .·* O3.Märzl999

In order to achieve a rotationally fixed connection between the drive element and the threaded spindle, either the drive element or the axial pressure ring or both can be clamped together via a truncated cone section.
This truncated cone section can be arranged on the drive element, for example, on a ring flange with a larger diameter than the axial pressure ring, which has a circular

shaped recess, the surrounding side wall of which forms the frustoconical cone section.

In diameter, this depression is limited to the
Axial thrust ring is adjusted in such a way that during axial movement this conical section, for example, clamps with the circumferential surface of the axial thrust ring in
effective connection can be made.

By the design according to claim 6, the clamping
or frictional connection is increased by the fact that the frustoconical cone sections have a roughened or toothed surface.

This design of the surface of the truncated cone
shaped conical sections, the coefficient of friction is increased so that a sufficient rotationally fixed connection between
the drive element and the threaded spindle

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J J***·»· * "·· * · · · * JS852 Villingen-Schwenningen (DE)

MN/win ····· ·· ·· ·· ·· 03 March 1999

caused by slight axial pressure against the drive element in the axial direction.

According to claim 7, the drive element can be screwed to the spindle head via a threaded connection. Depending on the design of the spindle drive, the threaded connection can be provided between the receiving bore of the drive element and the spindle head or between the receiving bore of the spindle head and the plug pin of the drive element.

It is understood that when the coupling pin between the drive element and the spindle head is sheared off, a relative rotation of the drive element with respect to the spindle head also causes an axial movement between the spindle head and the drive element, so that the frictional connection between these two components can also be achieved.

In order to ensure that, for example, a spring tensioner can only be released and not tensioned by the frictional connection, the threaded connection according to claim 8 is either designed to be left-handed if the threaded spindle for tensioning a coil spring is to be driven clockwise or vice versa, namely that the threaded connection of the drive element and the spindle head is designed to be right-handed if the threaded spindle

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys JJ*"*, ,J I *,, * ·. J * JSQ52 Villingen-Schwenmngen (DE)

MN/win *·«"··»»* *·.**··* ··* ··* O3.Märzl999

del is to be driven anti-clockwise to tension a coil spring. This special design of the threaded connection of the drive element and the spindle head ensures that the frictional connection between the drive element and the spindle head can only be established in one direction of rotation, which is intended for releasing a tensioned coil spring. If the rotation continues in the tensioning direction, the drive element is automatically unscrewed from the spindle head, so that further tensioning via this type of auxiliary drive via the frictional connection is safely excluded.

According to claim 9, instead of a conical section, the drive element and the threaded spindle can each have a toothing in the region of the spindle head, which can be brought into engagement with one another by the axial movement of the drive element relative to the threaded spindle.

According to claim 10, this toothing can be designed in a sawtooth manner, so that relatively high torques for the drive element and the threaded spindle can be achieved via the toothing, in particular for releasing the spring tensioner, while hardly any torque can be transmitted in the opposite direction of rotation due to the sawtooth-like tooth shape.

K230.doc

• t «

NeYMEYER & PARTNER GbR, Patent Attorneys J t*"*,«J I *«« *..i * J*552 Villingen-Schwenningen (DE)

MN/win *·#"··«' '·»"«»" ·· .» 03 March 1999

This design also significantly increases the safe handling of the spindle drive according to the invention, in particular for spring tensioners.

According to claim 11, such a toothing can also be provided between the axial pressure ring and the drive element, whereby here too a sawtooth-like toothing is preferred.

The invention is explained in more detail below with reference to the drawing. It shows:

Fig. 1 is a partial section through the spindle head of a spindle drive, in which the drive element is mounted on the spindle head via a receiving bore and a threaded connection;

Fig. la is an enlarged detail I of Fig. 1; Fig. lb is an enlarged detail II of Fig. 1;

Fig. 2 shows a spindle head of a spindle drive in which the drive element is mounted on the spindle head via a receiving bore without a threaded connection;

Fig. 3 a spindle head of a spindle drive with

a screwed-on drive element, which

K230.doc

NeymeYER & PARTNER GbR, patent attorneys · J"**··· · *·· »«?eOSi>Villingen-Schwenningen (DE)

MN/win *..*...* *.· *·· ·· ·· O3.Märzl999

can be brought into frictional connection with an axial thrust ring of the spindle head;

Fig. 4 a spindle head of a spindle drive with a drive element attached without a threaded connection, which is connected to an axial pressure ring

of the spindle head can be brought into frictional connection;

Fig. 5 shows a spindle head of a spindle drive, in which the drive element is axially inserted into a threaded bore with a threaded pin.

is screwed;

Fig. 6 is a sectional view of a spindle head in which the drive element is axially inserted with a plug pin into a receiving bore of the spindle head;

Fig. 7 shows a spindle head, an axial pressure ring and a drive element in a perspective exploded view, wherein the axial pressure ring and the drive element are each provided with a toothing;

Fig. 8 is a sectional view of the components of Fig. 7 in assembled state;

K230.doc

NEYMEYER & PARTNER GbR, patent attorneys · · "*"··· · ·· · *7eOdi>¥illingen-Schwenningen (DE)

MN/win *..*.··* *..**..* .. ·· O3.Märzl999

Fig. 9 shows the components from Fig. 7 and Fig. 8 in perspective view with engaged teeth;

Fig. 10 is a perspective exploded view of a spindle head, an axial thrust ring and

a drive element, in which the drive element and the spindle head have toothed elements;

Fig. 11 is a sectional view of the components of Fig. 10 in assembled state;

Fig. 12 the components from Fig. 10 and Fig. 11 in perspective view with engaged teeth.

Fig. 1 shows a spindle head 1 of a threaded spindle 2, such as is used for example in a spindle drive of a spring tensioner. The threaded spindle 2 is supported, as is already known from the prior art, in the axial direction via an axial thrust ring 3 on an axial thrust bearing in the guide tube of a spring tensioner (not shown in the drawing). The axial thrust ring 3 is mounted on a cylindrical receiving section 4 of the spindle head 1 and is firmly mounted on it via a locking pin 5. Additional

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys I ·***··! · ·· * · •TeOä&Villingen-Sclnvenningen (DE)

MN/win *..*·.·" ·· .· ·· ·· 03 March 1999

In addition to this locking pin 5, a threaded connection 5/1 can be provided between the axial pressure ring 3 and the receiving section 4 of the threaded spindle 2 or the spindle head 1 to absorb the axial forces that occur when a coil spring is tensioned on the axial pressure ring 3, as is also already known from the prior art and is shown as an example in dashed lines in Fig. 1. For the axial displacement of the tensioning elements of the spring tensioner, the threaded spindle 2 has a threaded section 2/1 which is operatively connected to an adjusting nut of the spring tensioner, by means of which one of the tensioning elements can be moved axially against the other tensioning element along the guide tube. This construction of a spring tensioner is also generally known and is therefore not shown in more detail in the drawing. The threaded section 2/1 of the threaded spindle 2 is normally designed as a right-hand thread, so that the threaded spindle 2 must be turned clockwise to tension a coil spring.

For rotating the threaded spindle 2 when tensioning a helical spring, the spindle head 1 is provided with a drive element 6, which has a drive hexagon 6/1 at its outer free end. This drive hexagon 6/1 is connected to a radially expanded annular collar 6/2 towards the axial pressure ring 3. For storage

K230.doc

NEYMEYER & PARTNER GbR, patent attorneys I J***··! I *.. * · ."feOSß.WHingen-Schwenningen (DE)

MN/win '..*...* ·· ·■ ·· ·· March 3, 1999

of the drive element 6 on the spindle head 1, the drive element 6 has a central, offset receiving bore 7, the outer end section of which is designed as a threaded bore 8. This threaded bore 8 is followed by a cylindrical guide section 9 of the receiving bore 7, which is enlarged in diameter, towards the threaded section 2/1 of the threaded spindle 2. Due to the different diameters of the threaded bore 8 and the guide section 9 of the receiving bore 7, a circumferential annular shoulder 12 is formed between them, directed towards the threaded section 2/1 of the threaded spindle 2. The spindle head 1 is also designed in accordance with this design of the receiving bore 7 of the drive element 6. It has a corresponding threaded pin 10 at its outer end, onto which the drive element 6 is removably screwed. Towards the receiving section 4 of the spindle head 1, a guide cylinder 11, which is also larger in diameter, is connected to the threaded pin 10, onto which the drive element 6 with its guide section 9 is pushed in the assembled state. The different diameters of the threaded pin 10 and the guide cylinder 11 of the spindle head 1 also form a circumferential shoulder 13 between them. As can be seen from Fig. 1, in the illustrated

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys I I***··· I *·· * . .iiOä&Winngen-Schwennijigen (DE)

MN/win *··*·#· ·· ·· ·· ·· O3.Märzl999

set axial target position, the drive element 6 is screwed onto the spindle head 1 only to such an extent that the ring shoulder 12 of the drive element 6 and the shoulder 13 of the spindle head have an axial distance A from each other, the meaning of which is explained in more detail below.

In this target position, the drive element 6 is secured on the spindle head 1 by a coupling pin 14. The coupling pin 14 extends through a cross hole 15 in the spindle head 1 and two cross holes 16 and 16/1 in the drive element 6, which are arranged axially in the area of the guide cylinder 11 and the annular collar 6/2. The coupling pin 14 and the cross holes 15, 16, 16/1 create a rotationally fixed connection between the spindle head 1 and the drive element 6, so that the threaded spindle 2 can be driven in rotation by the drive element 6 via its spindle head 1.

This non-rotatable connection forms an overload protection for the threaded spindle 2 when tensioning a coil spring, especially when the threaded spindle 2 is operated via the drive element 6 with a so-called impact wrench. If a coil spring is tensioned completely to the block when the threaded spindle 2 is used in a spring tensioner, the forces between the tensioning elements of the

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys I I * * *. . 1 I *. . ". .7i(fSÄ.\Jilliiigen-Schwenningen (DE)

MN /win *..*...**..**..* .·"..* 03. Mara 1999

Spring tensioner axially against one another so that a further reduction in the distance between the tensioning elements is no longer possible. If the threaded spindle 2 is actuated further in the tensioning direction, i.e. in a clockwise direction, extremely high combined tensile and torsional forces occur on the threaded spindle 2. If this load exceeds a certain level, the coupling pin 14 shears off so that the rotationally fixed connection between the drive element 6 and the threaded spindle 2 is canceled. In the present exemplary embodiment, it is further provided that the threaded connection between the drive element 6 consisting of the threaded bore 8 and the threaded pin 10 is designed as a left-hand thread, i.e. opposite to the right-hand thread of the threaded section 2/1 of the threaded spindle 2. If such a threaded spindle 2 with a right-hand thread is used, for example, in a telescopic spring tensioner, the threaded spindle 2 can also be driven clockwise to tension a coil spring. Consequently, after the coupling pin 14 has been sheared off, the left-hand thread between the drive element 6 and the spindle head 1 means that if the drive element 6 is rotated further in a clockwise direction, the latter is automatically unscrewed from the spindle head 1. However, this means that further tightening of the threaded spindle 2 via the drive element β is not possible.

K230.doc

NEYMEYER & PARTNER CbR, Patent Attorneys I !***·♦* · *. · * · •'isuSQaUillingen-Schwenningen (DE) MN/win *·.*.··* *..**..* ..* ..* O3.Märzl999

after breakage of the coupling pin 14 is safely excluded, so that overloading of the threaded spindle 2 cannot occur.

In order to be able to actuate the threaded spindle 2, in particular to release the spring tensioner or to relax the clamped coil spring, differently designed coupling parts are provided on the drive element and/or on the threaded spindle 2 or on the spindle head.

In the right half of the drawing in Fig. 1 as well as the enlarged detail I from Fig. 1 in Fig. la, an embodiment of such coupling parts is shown.

It can be seen that the receiving section 4 of the threaded spindle 2 is larger in diameter than the guide cylinder 11 of the spindle head 1. In the area of its end facing the drive element 6, the receiving section 4 is provided with a truncated cone section 17 as a coupling part. In the present embodiment, this cone section 17 partially projects into an axial recess 18 of the drive element 6. This recess 18 forms a circumferential ring wall 19, the inner wall of which is designed as a truncated cone section 20. The cone section 17 and the cone section 20 each have a pointed

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys 1 &iacgr; ***·· * *·· " · •'iiis^^Sllingen-Schwenningen (DE)

MN/win *··*··· ·· ·· ·· ·· 03 March 1999

Cone angles α and β, which can be the same or slightly different. Furthermore, the average diameters D of the cone section 17 and D2 of the cone section 20 are coordinated with one another in such a way that the cone sections 17 and 20 can be brought into frictional or force-locking contact with one another by an axial movement by the amount a, which is smaller than the axial distance A of the annular shoulder 12 of the drive element 6 to the shoulder 13 of the spindle head 1. This frictional or force-locking contact of the two cone sections 17 and 20 is brought about by the drive element 6 being rotated counterclockwise relative to the spindle head 1 and by the threaded connection between the threaded bore 8 of the drive element 6 and the threaded pin 10 of the spindle head 1 causing a relative axial movement between the drive element 6 and the spindle head 1 from the desired position shown to the position shown in phantom lines. After the axial movement has been completed by the amount a and by further driving the drive element 6 in an anti-clockwise direction, a rotationally fixed connection is created between the conical section 17 and the conical section 20 via the resulting frictional or force-locking connection, so that upon further actuation of the drive element 6, the threaded spindle 2 is rotated along

K230.doc

NEYMEYER & PARTNER GBK, Patent Attorneys I &idigr; ***··! * *·· * · &bull;^5<f52»A*iUingen-Schwenningen (DE) MN/win *··*···* *&diams;·**·· ·· ·· 03 March 1999

is caused. Since, with a helical spring clamped between the clamping elements, rotation of the threaded spindle 2 is inhibited by the existing thread friction between the threaded spindle 2 and the spindle nut and the drive element 6 can essentially rotate freely on the spindle head 1 after the coupling pin 14 has been sheared off, this relative rotation of the drive element 6 to the spindle head 1 can be carried out until its conical section 20 is in frictional or force-locking contact with the conical section 17 of the receiving section 4, without the threaded spindle 2 or the spindle head 1 having to be blocked by an additional tool. This means that a simple rotation of the drive element 6 by means of the key tool already used during clamping causes such a relative rotation between the drive element 6 and the spindle head 1, so that the desired axial movement takes place automatically via the threaded bore 8 and the threaded pin 10 and a rotationally fixed connection is created between the drive element 6 and the threaded spindle 2.

As an alternative to the two conical sections 17 and 20 shown in the right half of the drawing in Fig. 1 or in Fig. la, which can be brought into operative connection with one another, such truncated conical sections can also be provided only on the drive element 6 or only on the receiving section 4 of the spindle head 1, as is shown by way of example in

K230.doc

Ne YME YER & PARTNER GbR, patent attorneys ' J ***· · &Idigr; I *. . ' MN/win *·.*.··* *··**··* .·* .·* O3.Märzl999

the left half of the drawing in Fig. 1 and in Fig. 1b. In particular, it can be seen in solid lines from Fig. 1b that, for example, as already described for Fig. 1a, the drive element 6 is provided with the recess 18, the annular wall 19 of which forms the truncated cone section 20. The receiving section 4 of the spindle head 1, on the other hand, is cylindrical up to its end facing the drive element 6 and its diameter d is larger than the guide cylinder 11 of the spindle head 1, so that a circumferential shoulder 21 facing the recess 18 with a corresponding circumferential pressing edge 22 is formed. The larger diameter D3 of the conical section 20, which is located towards this pressing edge, is larger than the diameter d of the receiving section 4 or its circumferential pressing edge 22, while the smaller, inner diameter D4 of the conical section 20 is slightly smaller than the diameter d of the circumferential pressing edge 22. As can also be seen from the drawing, in the initial position shown, when the coupling pin 14 is not sheared off, the pressing edge 22 is at a small axial distance from the upper end face 23 of the drive element 6. After the coupling pin 14 breaks when tensioning a helical spring, the

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys JJ ***· « J I *· « " · ,'3*<TS!»>ii]]ingen-Schwenningen (DE)

MN/win "··"«·" "»·""··" ··* ··* O3.Märzl999

Fig. 1 or Fig. 1b, a rotationally fixed connection between the drive element 6 and the spindle head 1 and thus the threaded spindle 2 can be achieved by adjusting the drive element 6 axially relative to the spindle head 1, as already described for Fig. 1a or the right half of the drawing in Fig. i. The conical section 20 of the drive element 6 comes into frictional or force-locking contact with the pressing edge 22, so that a spring tensioner can also be released safely even after the coupling pin 14 has broken. This relative axial position of the drive element 6 to the spindle head 1 with frictional contact of the pressing edge 22 on the conical section 20 is shown in phantom lines in Fig. 1b.

It is understood that the recess 18 can have a cylindrical ring wall 19 that runs concentrically to the longitudinal center axis 24 of the threaded spindle 2 or the drive element 6, as shown in dashed lines in Fig. 1b. In this case, the receiving section 4 has the conical section 17 already described in Fig. la, which can be brought into a rotationally fixed, frictional or force-locking connection with the peripheral outer edge of the ring wall 19 after an axial movement of the drive element 6. The conical section

K230.doc

NEYMEYER & PARTiXER GbR, patent attorneys I &idigr;'**» · JI *. . *»»^UScUillingen-Schwenningen (DE)

MN/win »» »t» ·· »· ·· ·· 03. March 1999

Section 17 is also shown in dashed lines in Fig. Ib.

Fig. 2 shows a further embodiment of a spindle head 25, which is used, for example, in a spindle drive for spring tensioners. This spindle head is part of a threaded spindle 26/1 provided with a threaded section 26, which engages with the adjusting nut of the spring tensioner for the axial movement of a tensioning element.

The spindle head 25 has, at its end opposite the threaded section 26, a plug pin 27 with a tapered diameter, onto which a drive element 28 is plugged. The drive element 28 has a central receiving bore 29 which is offset and is provided with a plug bore 31 adapted to the plug pin 27 towards the outer end 30. Furthermore, the receiving bore 29 is provided with a radially expanded guide section 32 towards the threaded section 26 of the spindle head 25, with which the drive element 28 is plugged onto a guide section 33 adapted in diameter to correspond to this guide section 32.

In the area of its outer end section 34, the drive element 28 has, for example, a drive hexagon

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NEYMEYER & PARTNER GbR, Patent Attorneys I «"**·»· S 't · *».'^(TsZ.'Cuiingeii-Schwenningen (DE) MN /win t· &diams;»· ei it ·» ·· 03 March 1999

This is followed by a radially expanded guide collar 35 towards the threaded section 2 6, which is provided with transverse through holes 36 and 36/1.

In the area of these transverse through-holes 36, 36/1, the guide section 33 of the spindle head 25 is also provided with a transverse through-hole 37. In the axial position of the drive element 28 relative to the spindle head 25 shown, the drive element 28 is held on the spindle head 25 by a plug pin 38 which extends through the aligned through-holes 36, 36/1 and 37 of the drive element 28 on the one hand and the guide section 33 on the other. The drive element 28 is held in its axial position relative to the spindle head 25 by this coupling pin 38. Furthermore, when the drive element 28 is actuated, the coupling pin 38 transmits the drive torque to the spindle head 25 and thus to the threaded spindle 2/1.

As can be seen from Fig. 2, in this operating state the drive element 28 is not completely pushed onto the spindle head 25. The drive element 28 has an axial distance with its inner end face 39 of its plug bore 31 to the outer end face 40 of the

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plug pin 27. In the same way, the axial boundary surface 41 of the guide section 32 of the receiving bore 29 also has a corresponding axial distance from the circumferential shoulder 42 formed on the outside of the guide section 33, which results from the different diameters of the plug pin 27 and the guide section 33. Thus, the drive element 28 can be moved in the axial direction towards the threaded section 26 of the spindle head when the coupling pin 38 is removed.

Furthermore, an axial thrust ring 43 is provided on the spindle head 25 at a distance from the drive element 28, with which the spindle head and thus the entire threaded spindle 2/1 is axially supported on an axial thrust bearing (not shown in the drawing), for example a spring tensioner. The axial thrust ring 43 is in turn attached to the spindle head 25 in an axially immovable manner via a locking pin 44.

As shown in the right half of the drawing in Fig. 2, the guide bore 32 has in its end region facing the boundary surface 41 a truncated cone-shaped conical section 45 which tapers towards the boundary surface 41 and which, with its end facing the coupling pin 38, forms the circumferential

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NEYMEYER & PARTNER GbR, Patent Attorneys J J ··*.·· · ·· flee52*WBingen-Schwenningen (DE)

MN/win ',«*.·." *·«**··* ·· ·· 03 March 1999

Paragraph 42 of the guide section 33 has a certain distance. With this conical section 45, the drive element 28 can be clamped into connection with the guide section 33 of the spindle head 25 by an axial displacement of the drive element 28 in the direction of the threaded section 26 of the threaded spindle 2 6/1.

Instead of this conical section 45 in the area of the guide bore 32, a corresponding conical section 46 tapering towards the inner end face 39 of the plug bore 31 can also be provided in the area of the plug bore 31, as shown in dashed lines in the right half of the drawing in Fig. 2. This conical section 46 is also spaced from the end face 40 of the plug pin 27 with its plug pin-side boundary edge 47.

By means of a corresponding axial movement of the drive element 28 in the direction of the threaded section 26 of the spindle head 25, a rotationally fixed clamping connection between the drive element 28 and, in this case, the plug pin 27 of the spindle head 25 can also be achieved via this conical section 46.

Due to these clamping connections on the one hand between the conical section 45 and the guide section 33 or the conical section 46 and the plug pin 27, after shearing

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of the coupling pin 38, for example after an overload of the spindle drive, a rotationally fixed connection between the drive element 28 and the spindle head 25 can be achieved by a relative axial displacement of the drive element 28 to the spindle head 25. Thus, by means of this frictional clamping connection between the drive element 28 and the spindle head 25 after the coupling pin 38 has been sheared off, the spindle drive of a spring tensioner can be released again at any time in order to be able to release a coil spring clamped in this spring tensioner.

It is extremely advantageous that the clamping connection between the drive element 28 and the spindle head 25 can be achieved without an additional tool, in that the drive element 28 is brought into a corresponding clamping connection with the spindle head 25 by an axial displacement and then the spindle drive can be driven with one and the same tool with which the drive element 28 is otherwise driven.

In the left half of the drawing, an alternative design of both the plug pin 27 and the guide section 33 is shown in dashed lines. The plug pin 27 can itself be provided with a truncated cone section 48 at its outer end.

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which is inserted into a slightly smaller diameter end section 49 of the plug bore 31 by an axial displacement of the drive element 28 in the direction
of the threaded section 2 6 clamped in operative connection
can be brought.

Such a truncated cone section 50 can alternatively also be provided as an outer end section on the guide section 33, as shown in dashed lines in Fig. 2.
lines. Accordingly,

also the guide bore 32 towards the outer end with a smaller diameter cylinder section
51, with which the spindle head 25 can be brought into clamping connection via its conical section 50 when carrying out an axial movement of the receiving element 28 in the direction of the threaded section 26 of the spindle head 25.

It is understood that in the embodiments described in Fig. 2, both the conical sections 45 and 46 of the guide bore 33 and the plug bore 31
also frustoconical conical sections of the respective associated guide section 33 or plug pin 27 can be assigned, as already described in Fig. 1
The same applies to the conical sections
50 and 48 of the plug pin 27 or the guide

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NEYMEYER & PARTNER GBR, patent attorneys J !"**·.· · ·· p

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section 33 of the spindle head 25, to which conical surfaces in the corresponding axial region of the receiving bore 2 9 can also be assigned.

The conical sections 45, 46, 48 and 50 can also have a roughened or toothed surface in order to increase the frictional engagement between these conical surfaces and the respective associated bore section or section of the spindle head 25 for torque transmission.

A through-thread 53 is provided in the front wall 52 of the drive element 28, into which a press screw 54 (shown in phantom lines) can be screwed. This press screw 54 is used to pull the drive element 28 off the spindle head 25. This may be necessary if the frictional connection between the drive element 28 and the spindle head 25 can no longer be released manually. By screwing the press screw 54 into the through-thread 53, it comes to rest on the front surface 40 of the plug pin 27, so that when the press screw 54 is screwed further into the through-thread 53, the drive element 28 is pulled off the spindle head 25 and the frictional connection between the drive element and the spindle head 25 is released accordingly.

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NEYMEYER & PARTNER GbR, patent attorneys J J ***··· · ··

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Fig. 3 shows a further embodiment of a spindle head 55, which is rotatably mounted via an axial thrust bearing 56 in the end region of a guide tube 57 of a spring tensioner. Such a bearing is used, for example, in spring tensioners, as in the state of the

Technology, for example DE-296 12 001 Ul. The spindle head 55 is part of a threaded spindle
58, whose threaded section 59 in Fig. 3 is still
is partially visible.

To accommodate the thrust bearing 56, the end of the
A corresponding bearing bush 60 is screwed into the guide tube 57,
which has a radially inward directed
Stop web 61, on which the axial thrust bearing 56 is axially supported when tightening a screw.

spring. To support the threaded spindle 58
with its spindle head 55 on the outside of the
Axial thrust bearing 56 is provided with an axial thrust ring 62 which is firmly secured by means of a locking pin 63
to a corresponding receiving section 64 of the spin-

delkopf 55 is mounted.

In external extension to the receiving section 64
the spindle head 55 has an external thread 65 which projects beyond the outer end of the bearing bush 60. On this
A drive element 66 is screwed onto the external thread 65,

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which is also non-rotatable via a coupling pin 67 and is attached to the spindle head 55 in an axially defined position relative to the latter. In this axial position of the drive element 66 relative to the spindle head 55, defined via the coupling pin 67, the drive element 66, as can be clearly seen from Fig. 3, has a small axial distance from the outermost end face 68 of the axial pressure ring 62.

The drive element 66 is provided with a radially expanded support collar 69 towards the axial thrust ring 62. Furthermore, the axial thrust ring 62 has a recess 71 towards the drive element 66 which is arranged concentrically to the longitudinal center axis 70 of the spindle head 55 and whose circumferential side wall forms a truncated cone-shaped conical section 72 which tapers towards the axial thrust bearing. The dimensions of this conical section 72 are matched to the outer diameter of the support collar 69 in such a way that when the drive element 66 moves with its support collar 69 into this recess 71, a frictional connection between the support collar 69 and the conical section 72 can be achieved.

Such an axial movement is achievable, for example, when the coupling pin 67 is sheared off and the drive element 66 is displaced by a relative rotation to the

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NEYMEYER & PARTNER GbR, Patent Attorneys J !***.. &idigr;&Sgr; *·· " &bull;'S»52»ViMingen-Schwenningen (DE)

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threaded spindle 58 is screwed axially into the recess 71 or the conical section 72 of the axial pressure ring 62. This axial movement also creates a rotationally fixed connection between the drive element 66 and the axial pressure ring 62, so that the threaded spindle 58 can continue to be driven in rotation via the drive element 66 after the frictional connection has been achieved via the pin connection between the axial pressure ring 62 and the threaded spindle 58 or its spindle head 55.

The threaded connection 73 between the drive element 66 and the threaded pin 74 is designed to be left-handed, provided that the threaded spindle 58 with its threaded section 59 is to be driven clockwise to tension a coil spring. This means that a frictional connection between the drive element 66 and the axial pressure ring 62 is only possible in a counterclockwise relaxation direction, so that a coil spring tensioned in a spring tensioner can be relaxed. Tensioning is not possible in the opposite direction of rotation, since in this case, when the drive element 66 rotates relative to the threaded spindle 58, it is screwed down from the threaded pin 74 and thus a frictional connection between the drive element 66 and the axial pressure ring 62 cannot be achieved.

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NEYMEYER & PARTNER GbR, Patent Attorneys JJ ***· · &idigr; * *· · &bull;'JÖ05»"iMingeii-Schwenningen(DE)

MN/win ·..*..." ·..*·*·* ··' ·· O3.Märzl999

Fig. 4 shows a further embodiment of a spindle head 75, which is rotatably mounted via two axial thrust bearings 76 and in a bearing bush 78. For the axial support of the axial thrust bearings 76 and 77 in the bearing bush 78, the bearing bush 78 is provided with a radially inwardly directed stop web 79.

This bearing is part of a spring tensioner, as described, for example, in DE 296 12 001 Ul. Accordingly, the bearing bush 7 8 is screwed into one end of a guide tube 80, which serves as part of a spring tensioner for receiving the tensioning elements (not shown in the drawing).

The spindle head 75 is part of a threaded spindle 81, which has a threaded section 82 that connects to the spindle head 75 within the guide tube 80. The threaded spindle 81 with its spindle head runs coaxially to the guide tube 80.

For axial support on the two axial thrust bearings 77 and 81, the spindle head 75 of the threaded spindle 81 has two axial thrust rings 83 and 84, of which the axial thrust ring 83 is axially supported on the axial thrust bearing 77 within the guide tube 80, while the second axial thrust ring 84 is used for axial support of the spindle head 75 and thus the threaded spindle 81 with the external

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axial thrust bearing 76 is in operative connection. The
Both axial thrust rings 83, 84 are each secured with a locking pin 85 or 86 on a cylindrical receiving section 87 of the spindle head 75 axially
set.

In axial extension outside the outer axial pressure ring 84, the spindle head 75 has a guide section
88 and an adjoining receiving pin 89. The receiving pin 89 is smaller in diameter than the guide section 88, so that a circumferential shoulder 90 is formed between the two.

A drive element 91 is fitted onto this guide section 8 8 and the receiving pin 8, which is provided with a correspondingly offset bearing bore

92, which is inserted into an outer receiving section

93 and an adjoining axial thrust ring 84
guide section 94, which also form a circumferential bore shoulder 95.

On the outside, the drive element 91 has a drive hexagon 96 at the outer end, to which
of the drive element 91 and thus the threaded spindle 81, a key tool can be attached accordingly.
Axial thrust ring 84 is connected to the outside of the

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NEYMEYER & PARTNER GbR, Patent Attorneys J &iacgr; **"··· · *·· * &bull;iSOSJVälingen-SchwenningenCDE)

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drive element 91 is provided with a radially expanded annular collar 97, in the area of which transverse through-bores 98 are arranged.

Furthermore, the spindle head 75 is also provided with a transverse through-bore 99 in the region of its guide section 88. The drive element 91 is, as can be seen from Fig. 4, connected to the spindle head 75 in a rotationally fixed manner by means of a coupling pin 100, wherein the coupling pin 100 extends through the through-bores 98 and 99 of the guide section 88 of the spindle head 75 and of the drive element 91 together.

The axial position of the through hole 98 in the guide section 88 of the spindle head 75 and the through hole 99 in the drive element 91 is selected such that the drive element 91 with the circumferential hole shoulder 95 and the circumferential shoulder 90 of the spindle head 75 are axially spaced from one another. The same applies to the outer end face 101 of the receiving pin 89, which is also axially spaced from the outermost end wall 102.

This means that after removal or shearing of the coupling pin 100, the drive element 91 can be moved in the axial direction towards the axial pressure ring 84. Due to this axial movement, the drive element 91 is connected to the,

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Neymeyer & PARTNER GbR, patent attorneys J i *"*· · &iacgr; * *·· *l^)&VUIingen-Scliweiiiiingen(DE)

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axial thrust ring 84, which is connected to spindle head 75 in a rotationally fixed manner via coupling pin 86, is frictionally engaged
bringable.

For this purpose, as shown in the right half of the drawing in Fig. 4, the drive element 91 has a recess 103 directed towards the axial pressure ring 84, the outer boundary wall 104 of which forms a circumferential, frustoconical conical section 105 which tapers in the direction of the coupling pin 100.

The dimensions of this conical section 105 are adapted to the diameter D4 of the axial pressure ring 84 in such a way that the conical section 105 is frictionally engaged by a relative axial movement of the drive element 91 to the spindle head 75.
with the outer edge area 106 of the

Axial pressure ring 84 can be brought into operative connection.

This frictional connection creates a rotationally fixed connection between the drive element 91 and the
Axial pressure ring 84 causes, so that when the
axially displaced drive element 91 over the
Axial pressure ring 84 and its locking pins 86 drive the threaded spindle 81. The clamping forces or
Frictional forces between the conical section 105 and the edge area 106 of the axial pressure ring 84 are at least so large that a release of a spring tensioner, in which

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NEYMEYER & PARTNER GbR, Patent Attorneys J J *·*.·! i *·» * «!^»Vglingeii-Schwenningen (DE)

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where a coil spring is clamped, can be carried out safely.

As shown in the left half of the drawing in Fig. 4, the boundary wall 104 of the recess 103 can also be cylindrically designed coaxially to the longitudinal center axis 107 of the spindle head 75. In order to enable a clamping frictional connection during the axial movement of the drive element 91 with the axial pressure ring 84, this axial pressure ring 84 has a circumferential truncated cone-shaped conical section 109 in its outer end region of its outer surface 108 facing the drive element 91.

This conical section 109 can be brought into a clamping frictional connection with the cylindrical boundary wall 104 of the recess 103 in accordance with the conical section 105 and the edge region 106 of the axial pressure ring 84 shown in the right-hand half of the drawing, so that a rotationally fixed connection between the drive element 91 and the axial pressure ring 84 can also be achieved by this clamping frictional connection.

In order to be able to release the drive element 91 from its frictional clamping connection with the axial pressure ring 84, the end wall 102 of the drive element 91 also has a central through-hole 110 in which

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NEYMEYER& PARTNER GbR, Patent Attorneys j J *··. » S · ·« .'JSBsiVfflingen-SchwenningenpE)

MN/win *.·*···* *..**.·* ··* ··* 03 March 1999

into which, as already described in Fig. 2, a corresponding pressing screw (not shown in the drawing) can be screwed in to remove the drive element 91 from the spindle head 75.

Fig. 5 shows a further embodiment of a spindle head 115, which has a central threaded bore 117 for receiving a drive element 116. The drive element 116 has a drive hexagon 118 on the outside and is screwed into the threaded bore 117 of the spindle head 115 by means of a threaded pin 119.

To produce a rotary connection between the drive element 116 and the spindle head 115, a coupling pin 120 is provided which extends jointly through a corresponding through-bore 121 of the spindle head 115 and a through-bore 122 of the threaded pin 119 of the drive element 116.

The axial arrangement of the through hole 121 and the through hole 122 is selected so that the drive hexagon 118 with its circumferential collar 123 is at an axial distance from the outer face 124 of the spindle head 115. Furthermore, the inner face 125 of the threaded pin 119 is also spaced from the bore end 126 of the threaded hole 117, so that after removal

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NEYMEYER & PARTNER GbR, Patent Attorneys I J··*.,! I *·· * «1^)52· VÄlingen-Schwenningen (DE)

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If the coupling pin 120 is removed or broken, the drive element 116 can be screwed further into the threaded bore 117 in the axial direction.

As can be seen from the right half of the drawing in Fig. 5, the threaded pin 119 of the drive element 116 has a tapered truncated cone section 127 at its end located in the threaded bore 117. Furthermore, a cylindrical section 128 with a smaller radial diameter is provided in the threaded bore 117, the diameter of which is matched to the dimensions of the cone section 127 in such a way that when the drive element is screwed in

116 with its threaded pin 119 into the threaded hole

117 the conical section 127 can be brought into clamping connection with the cylinder section 128.

This clamping connection creates a rotationally fixed connection between the drive element 116 and the spindle head 115. Preferably, the thread of the threaded hole 117 and the threaded pin 119 is designed against the clamping direction, for example as a left-hand thread, provided that the threaded spindle 130 with its threaded section 129 indicated at the upper end of the spindle head 115 is to be driven clockwise for clamping a helical spring. If the clamping direction of the threaded spindle 130

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for tensioning a coil spring, however, anti-clockwise, the thread of the threaded hole 117 should be designed as a right-hand thread. This design of the threaded hole 117 and the threaded pin 119 as well as the thread 129 of the threaded spindle 130 ensures that the clamping, rotationally fixed connection via the conical section 127 and the cylinder section 128 can only be established for releasing a spring tensioner, i.e. that the drive element 116 with its threaded pin 119 is screwed axially into the threaded hole 117 in a counterclockwise direction of rotation until it is in an operative connection with its conical section 127 in a clamping manner with the cylinder section of the threaded hole 117.

The left half of the drawing in Fig. 5 shows a further possibility for producing a rotationally fixed clamping connection between the threaded pin 119 and the threaded bore 117. For this purpose, the threaded pin has a smaller diameter, cylindrical clamping section 131 at its inner end. Associated with this is a truncated cone section 132 of the threaded bore 117. The dimensions of the cone section 132 and the clamping section 131 are coordinated in such a way that when the drive element 116 moves axially with its coupling pin 119 by screwing it into the threaded bore 117, the latter is

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NE YME YER & PARTNER GbR, Patent Attorneys J J***··· · "·· *»5&£*välingen-Schwenningen(DE)

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a frictionally engaged clamping connection. Here too, a clamping, frictionally engaged, rotationally fixed connection between the drive element 116 and the spindle head 115 can be produced in a simple manner, so that a spring tensioner in which such a construction is used as a drive can be released again at any time, even after the coupling pin 120 breaks.

By subsequently rotating the drive element 116 clockwise relative to the spindle head 115, the described clamping connection is inevitably canceled again due to the associated unscrewing of the threaded pin 119 from the threaded bore 117, so that the broken coupling pin 120 can subsequently be replaced.

Fig. 6 shows a further embodiment of a spindle head 135, which is provided at one end with a receiving bore 138 arranged coaxially to its longitudinal center axis 137 for receiving a drive element 136. The spindle head 135 is part of a threaded spindle 139, which has a corresponding threaded section 140 in axial extension to the spindle head 135. The drive element 136 consists of a drive hexagon 141 and a plug pin 142, with which the drive element 136 fits into the receiving bore 138.

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NEYMEYER & PARTNER GbR, Patent Attorneys J J *"*··· · *·· *tjäDälvSlingen-Schwenningen(DE) MN/win *..*.«&diams;* ·.·**..* ··* ··* March 3, 1999

bore 138 of the spindle head 135. For the rotationally fixed connection of the drive element 136 and for its axial fixing with its plug pin 142 in the receiving bore 138 in the spindle head 135, two coupling pins 143 and 144 are provided, which simultaneously serve for the axial fixing of an axial pressure ring 145. Accordingly, the axial pressure ring 145 as well as the spindle head 135 and also the plug pin 142 have corresponding through-bores or cross-bores 146, 147 and 148. The arrangement of the cross holes 147 of the spindle head 135 and the through hole 148 of the plug pin 142 as well as the cross holes 146 of the axial pressure ring 145 is selected such that the drive element 136 or its drive hexagon 141 with its spindle head-side collar 149 has an axial distance from the end face 150 of the spindle head 135. Such a distance is also provided between the inner face 151 of the plug pin 142 and the end 152 of the plug hole 138. Due to this axial distance, the drive element 136 with its plug pin 142 can be pushed further axially into the receiving hole 138 if the coupling pins 143 and 144 are broken. This axial displacement or axial movement creates a clamping, frictional, rotationally fixed connection between the drive element 136 and the spindle head 135.

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Neymeyer & PARTNER GbR, patent attorneys MN/win

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For this purpose, the right half of the drawing shows the
Fig. 6 in the area between the front side 150 of the spindle head
135 and the ring collar 149 of the drive hexagon
141, a truncated cone-shaped cone section 153 is provided, which widens to the annular collar 149 and
the mounting hole 138 during axial displacement of the drive element
136 into a frictional, clamping,
a rotationally fixed connection can be made.

Furthermore, as shown in the left half of Fig. 6, the mounting hole 138
be provided in the region of its outer end with a truncated cone section 154, which is provided with a
radially expanded cylinder section 155 of the plug pin 142 by axial displacement of the drive element 136
frictionally and thus non-rotatably connected. Through these frictionally engaged, non-rotatable connections
between the drive element 136 and the spindle head
135 ensures that the threaded spindle 139 can continue to be operated after the coupling pins 143 and 144 have been sheared off or broken. To do this, the drive element 136' only has to be pushed axially relative to the threaded spindle 139 into its spindle head 135.

In order to create this clamping connection between the cone sections
153 and the receiving bore 138 or the Ke-

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In order to be able to release the screw from the gel section 154 and the cylinder section 155 again, the drive element 136 has a central, through-threaded bore 156 into which a press screw can be screwed, as already described for Fig. 2. This press screw is accordingly screwed through the threaded bore 156 until it rests in the lower end 152 of the receiving bore 138 of the spindle head 135 and by further actuation the entire drive element 136 is pressed out of the receiving bore 138, removing the frictional connection. In order to be able to screw in the press screw completely, the two coupling pins 143, 144 are spaced apart from one another by an appropriate distance in the area of the threaded bore 156.

Fig. 7 shows a further embodiment of a threaded spindle 160, an axial pressure ring 161 and a drive element 162 in a perspective exploded view. The threaded spindle 160 has a threaded section 163, only partially shown in Fig. 7, to which a spindle head 164 is connected, which has a cylindrical receiving section 165, a cylindrical guide section 166 and a cylindrical receiving pin 167 for receiving the axial pressure ring 161 and the drive element 162.

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For mounting on the cylindrical receiving section, the axial pressure ring 161 has a central through-hole 168, with which the axial pressure ring 161 can be pushed onto the receiving section 165. As can also be seen from Fig. 7, the receiving section 165 is provided with a through-hole 170 running transversely to the longitudinal center axis 169 of the threaded spindle 160, with which two diametrically opposed through-holes 171 and 172 in the axial pressure ring 161 can be brought into overlap. To secure the axial position of the axial pressure ring 161, a locking pin 173 is provided, which in the assembled state extends through the through-holes 170 of the receiving section 165 and the two through-holes 171 and 172 of the axial pressure ring.

The drive element 162 has a drive hexagon 174 at its outer end, to which a radially expanded annular collar 175 is connected towards the threaded spindle 160. For mounting on the guide section 166 and the receiving pin 167, the drive element 162 is provided with a central, offset bearing bore 176, which forms a receiving bore 177 and a pin bore 178 of smaller diameter (shown in dashed lines). The diameter of the receiving bore 177 is the same as the diameter of the guide section

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NEYMEYER & PARTNER GbR, Patent Attorneys I J·*·,.! I *.. * · · I 78ftSe VilUngen-Schwenningen (DE)

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166 of the spindle head 164, while the pin bore 178 is correspondingly adapted to the diameter of the receiving pin 167, so that the drive element 162 can be pushed onto the guide section 166 or the receiving pin 167 at least almost without play. As can also be seen from Fig. 7, a transverse bore 179 is also provided in the area of the guide section 166, through which a coupling pin 180 can be inserted. This coupling pin 180 serves for the axial fixing and rotationally fixed connection of the drive element 162 to the spindle head 164 or its receiving section 165 and the guide section 166. For this purpose, the drive element 162 is also provided in the area of its extended annular collar 175 with two through holes 182 and 183 running transversely to the longitudinal center axis 181 of the drive element 162, which are aligned with the transverse hole 179 of the receiving section 166 during assembly. In this state, the coupling pin 180 is inserted through the through holes 182 and 183 and through the transverse hole 179 for a firm hold of the drive element 162 on the spindle head 164.

As can also be seen from Fig. 7, the axial pressure ring 161 has a sawtooth-like, circumferential toothing 184 towards the drive element 162. With this

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Neymeyer & PARTNER GbR, Patent Attorneys J J * * * · · &Sgr; * *«·*··· ^eese VUlingen-Schwenningen (DE)

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The drive element 162 can be brought into a rotationally fixed connection via the toothing 184 of the axial pressure ring 161 and for this purpose also has a circumferential toothing 185 aligned with the axial pressure ring 161.

Fig. 8 shows the threaded spindle 160, the axial pressure ring 161 and the drive element 162 together with the locking pin 173 and the coupling pin 180 in the assembled state. It can be seen that the axial position of the through hole 170 of the receiving section 165 and the transverse hole 179 of the guide section 166 and the axial position of the through holes 170, 171 of the axial pressure ring 161 and the through holes 182 and 183 of the drive element 162 are coordinated with one another in such a way that the teeth 184 of the axial pressure ring 161 and 185 of the drive element 162 do not engage with one another when correctly assembled, but have a small axial distance from one another. Furthermore, in this correctly mounted position of the drive element 162 on the guide section 166 and the receiving pin 167, a further axial movement of the drive element 162 relative to the threaded spindle 160 or its spindle head 164 is safely possible when the coupling pin is removed. This is achieved by maintaining an axial distance between the circumferential annular shoulder 186 formed by the receiving bore 177 and the pin bore

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NEYMEYER & PARTNER GbR, Patent Attorneys J &idigr; ***· #. &idigr;&idigr; *·· * · · · *7«&bgr;52 Villingen-Schwenningen (DE)

MN/win ·.,*...* *..**.." ..* »· O3.Märzl999

to the likewise circumferential ring shoulder 187, which is formed by the guide section 166 and the receiving pin 167 due to their different diameters. Furthermore, the outer end face 188 of the receiving pin 167 in this correctly assembled state also has a corresponding distance from the end wall 189 of the drive element 162, so that after the coupling pin 180 has been removed or broken or sheared off, a relative axial movement between the drive element 162 and the spindle head 164 of the threaded spindle 160 can be carried out safely. However, as shown in Fig. 9, this axial movement now causes the teeth 184 of the axial pressure ring 161 to engage with the teeth 185 of the drive element 162. This ensures a rotationally fixed connection between the drive element 162 and the axial pressure ring 161 of the threaded spindle 160 by axial displacement or an axial movement of the drive element 162 relative to the axial pressure ring 161 or the threaded spindle 160 after the coupling pin 180 (not shown in Fig. 9) has been sheared off. The design of the two gears 184 and 185 as a sawtooth connection ensures a secure torque transmission between the drive element 162 and the

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J &idigr; "*· « &iacgr; · *#·*··· *7«&bgr;52 VUlingen-Schwenningen (DE)

MN/win '..·...' "..'·..' .·* ··* O3.MUrzl999

Axial pressure ring 161 and the threaded spindle 160, which is still connected to it in a rotationally fixed manner via the locking pin 173. In the opposite direction of rotation, clockwise in the present embodiment, however, a transmission of a drive torque via this sawtooth-like toothing 184, 185 is only possible with difficulty, so that further tensioning of a coil spring clamped in a spring tensioner is definitely ruled out. It should be noted that the tooth height of the toothings 184 and 185 is shown relatively large for reasons of clarity. It is understood that, in order to allow only one direction of rotation, the tooth height can be significantly lower, so that the oblique rear tooth flanks also have only a small pitch, so that a torque transmission in a clockwise direction through the toothings 184 and 185 is in principle impossible. The design of the spindle drive according to Fig. 7 to 9 also provides a simple way of driving the drive element 162 for the correct operation of a spring tensioner with one and the same tool. By axially displacing the drive element 162 relative to the threaded spindle 160 in the direction of the axial pressure ring 161 in the event of the coupling pin 180 shearing off, the two gears 184 and

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J !***·«· · *··*··· ^7S0il Villingen-Schwenningen (DE)

MN/win '..*...* *··**·.* ··* ··* O3.Märzl999

can be easily engaged with one another so that the spring compressor can be released and repaired using the same tool that is used to normally operate the spring compressor.

Fig. 10, 11 and 12 show a threaded spindle 195 with a partially shown threaded section 196 and a spindle head 197 on which an axial pressure ring can be firmly mounted. Furthermore, the spindle head 197 is provided with a central receiving bore 199 into which a drive element 200 with a plug pin 201 can be inserted. The axial pressure ring

198 has a central through hole 202, with which the axial pressure ring 198 can be pushed onto the cylindrical spindle head 197. Both the axial pressure ring 198 and the spindle head 197 are in the area of their through hole 202 or receiving hole

199 each provided with two opposite transverse bores 203, 204 and 205, 206, which run transversely to the longitudinal center axis 207 of the threaded spindle 195 or the spindle head 197. For axial fixing of the drive element 200, this also has a transverse bore 208 in the area of its plug pin 201, which is aligned with the two transverse bores 205 and 206 of the spindle head 197 when the drive element 200 is mounted on the spindle head 197. For axial fixing

K230.doc

Neymeyer & PARTNER GbR, patent attorneys &iacgr; !***··· &bgr; *··*··· *18&thgr;&dgr;2 Villingen-Schwenningen (DE) MN/win .. ... c· ·· ·· ·· 03 March 1999

A coupling pin 209 is provided for the installation, which in the assembled state extends through both the transverse bores 205, 206 of the spindle head 197 and the transverse bores 203 and 204 together with the transverse bore 208 of the plug pin 201 of the drive element 200. This defines the axial position of the axial pressure ring 198 relative to the spindle head 197. Furthermore, in the assembled state the drive element is connected in a rotationally fixed manner to the spindle head 197 by the coupling pin 209, whereby at the same time its axial position, as can be seen in particular from Fig. 11, is clearly defined with respect to the spindle head 197.

At its end opposite the plug pin 201, the drive element 200 is provided with a drive hexagon 210, via which the threaded spindle 195 can be driven in rotation in the spindle head 197 by means of a corresponding key tool when the drive element 200 is mounted as shown in Fig. 11. Between the drive hexagon 210 and the plug pin 201 of the drive element 200, an annular collar 211 is provided, which projects radially outward beyond both the drive hexagon 210 and the plug pin 201. This annular collar 211 is interrupted at two opposite points 212 and 213 and forms a toothing element 214 and 215. As a counterpart to these toothing elements

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J &idigr; ***.·! I *··*··· *T80S2 Villingen-Schwenningen (DE) MN /win *·.*...""«»**··" &diams;·*..* 03 March 1999

214 and 215, the spindle head 197 also has two toothed elements 217 and 218 on its front-side annular web 216, which can be brought into engagement with the toothed elements 214 and 215 by axially inserting the drive element 200 into the receiving bore 199 of the spindle head 197. Through this connection, as shown by way of example in Fig. 12, in the present exemplary embodiment a left-hand rotation in an anti-clockwise direction is ensured by the drive element 200 via the toothed elements 214 and 215 and the toothed elements 217 and 218 of the spindle head 197. In the case of a right-hand threaded section 196 of the threaded spindle 195, this anti-clockwise rotation enables a coil spring clamped in the spring tensioner to be released or relaxed in a spring tensioner. However, in the opposite direction of rotation (clockwise), a positive connection through the toothed elements 214, 215 and 217, 218 is not possible, since their rear flanks 219, 220 and 221 and 222 are so flatly inclined that a torque connection via these flanks 219, 220 and 221, 222 is not possible. This prevents a further tensioning of a coil spring, which is clamped in a spring tensioner, via the toothed elements 214, 215 and 217, 218.

K230.doc

NEYMEYER & PARTNER GBR, Patent Attorneys * &iacgr; ***, , 2 · ·· ··· &Tgr;&bgr;&bgr;«2 Villingen-Schwenningen (DE)

MN/win "..'...* *.·**.·" ··" ··* 03 March 1999

As can be further seen from Fig. 11, the axial position of the transverse bore 208 of the plug pin 201 and the axial position of the transverse bores 205 and 205 are coordinated with one another in such a way that, in the correctly assembled state, the toothing elements 214, 215 of the drive element 200 and the toothing elements 217, 218 are at an axial distance from one another and are therefore not in engagement.

The design of the spindle drive according to the invention results in a rotationally fixed connection between the drive element and the threaded spindle in the form of a clamping frictional connection or an intermeshing toothing by axially moving the drive element relative to the spindle head or the threaded spindle. This has the decisive advantage that the drive element, which was originally mounted rotationally fixed with the coupling pin on the spindle head, can be brought back into a rotationally fixed connection with the threaded spindle by a simple axial movement relative to the spindle after the coupling pin has been sheared off. By appropriately designing the toothing elements or by appropriately designing the threaded connection between the drive element and the spindle head, a preferred direction of rotation can be selected, which is necessary, for example, for releasing a spring tensioner. If such a

K230.doc

NEYMEYER & PARTNER GbR, Patent Attorneys J &idigr; ***··! &iacgr; *··*··* *&Tgr;80&2 Villingen-Schwenningen (DE)

MN/win *··*···" ·· ·· ·» ·· 03 March 1999

If the direction of rotation is specified, it is essentially impossible to use such a spindle drive with a
Spring tensioner to further tension a coil spring clamped or pre-tensioned in this spring tensioner after the coupling pin has been sheared off. A release of this pre-tensioned
Coil spring or spring tensioner is ensured, so that the spring tensioner, in particular
when used on a motor vehicle, can be released at any time and removed from the coil spring. This allows the sheared coupling pin to be replaced easily
so that the spring compressor can be used again
The main advantage here is that with one and the same key tool that is used for normal operation of the spring compressor or the spindle

drive is provided, the additional non-rotatable
Connection through the axial displacement of the drive element
regarding the threaded spindle can be manufactured.
This considerably simplifies the handling of a spring compressor,
which is provided with the spindle drive according to the invention.

K230.doc

Claims (11)

1. Spindle drive, in particular for spring tensioners, with a threaded spindle ( 2 , 26/1 , 58, 81, 130, 139, 160, 195) having a spindle head (1, 25, 55, 75, 115, 135, 164, 197) and a threaded section (2/1, 26, 59 , 82 , 129 , 140 , 163 , 196 ) , which has a drive element ( 6 , 28 , 66, 91) for actuating the threaded spindle (2 , 26/1 , 58 , 81 , 130 , 139 , 160 , 195 ) . , 116 , 136 , 162 , 200 ), which is connected as a separate component to the spindle head ( 1 , 25 , 55 , 75 , 115 , 135 , 164 , 197 ) by at least one coupling pin ( 14 , 38 , 67 , 100 , 120 , 143 , 144 , 180 , 209 ), wherein the threaded spindle ( 2 , 26 / 1 , 58 , 81 , 130 , 139 , 160 , 195 ) is rotatably mounted in a guide tube ( 57 , 80 ) via at least one axial thrust bearing ( 56 , 76 , 77 ), characterized in that the drive element ( 6 , 28 , 66 , 91 , 116 , 162 , 200 ) with the threaded spindle ( 2 , 26 / 1 , 58 , 81 , 130 , 139 , 160 , 195 ) via one or more coupling parts ( 17 , 19 , 20 , 22 , 27 , 33 , 45 , 46 , 48 , 49 , 50 , 51 , 69 , 72 , 104 , 105 , 106 , 109 , 127 , 128 , 131 , 132 , 138 , 153 , 154 , 155 , 184 , 185 , 214 , 215 , 217 , 218 ) after removing the connection between the drive element ( 6 , 28 , 66 , 91 , 116 , 162 , 200 ) and the spindle head ( 1 , 25 , 55 , 75 , 115 , 135 , 164 , 197 ) by carrying out an axial movement of the drive element ( 6 , 28 , 66 , 91 , 116 , 162 , 200 ) relative to the threaded spindle ( 2 , 26 / 1 , 58 , 81 , 130 , 139 , 160 , 195 ) can be brought into a frictional or positive-locking, rotationally fixed connection. 2. Spindle drive according to claim 1, characterized in that the drive element ( 6 , 28 ) has a central receiving bore ( 7 , 29 ) with which the drive element ( 6 , 28 ) is arranged on the spindle head ( 1 , 25 ) with axial play,
or that the drive element ( 116 , 136 ) is provided with a pin ( 119 , 142 ) with which the drive element ( 116 , 136 ) is arranged in a receiving bore ( 117 , 138 ) of the spindle head ( 115 , 135 ) with axial play, and
that the receiving bore ( 7 , 29 , 117 , 138 ) has, as a coupling part, a frustoconical conical section ( 20 , 45 , 46 , 132 , 154 ) arranged coaxially to the receiving bore ( 7 , 29 , 117 , 138 ), with which the drive element ( 6 , 28 , 116 , 136 ) can be brought into a clamping, rotationally fixed connection with the threaded spindle ( 2 , 26/1 , 130 , 139 ) by its relative axial movement to the threaded spindle ( 2 , 26/1 , 130 , 139 ). 3. Spindle drive according to claim 1, characterized in that the spindle head ( 1 , 25 ) of the threaded spindle ( 2 , 26/1 ) or the pin ( 119 , 142 ) of the drive element ( 116 , 136 ) has a truncated cone-shaped cone section ( 17 , 48 , 50 , 127 , 153 ) tapering towards the drive side, which can be connected to a part ( 19 , 20 , 49 , 51 , 132 , 138 ) of the receiving bore ( 7 , 29 , 117 , 138 ) of the drive element ( 6 , 28 ) or of the spindle head ( 115 , 135 ) by the relative axial movement of the drive element ( 6 , 28 , 116 , 136 ) can be clamped into a rotationally fixed connection with the threaded spindle ( 2 , 26/1 , 130 , 139 ). 4. Spindle drive according to one of claims 1 to 3, characterized in that the receiving bore ( 7 or 117 ) of the drive element ( 6 ) or the spindle head ( 115 ) and the spindle head ( 1 ) or the pin ( 119 ) of the drive element ( 116 ) each have a truncated cone section ( 17 , 20 , 127 , 132 ) which can be brought into a mutually clamping, rotationally fixed connection by the relative axial movement of the drive element ( 6 , 116 ) relative to the threaded spindle ( 2 , 130 ). 5. Spindle drive according to claim 1, characterized in that the threaded spindle ( 58 , 81 ) has an axial pressure ring ( 62 , 84 ) in the region of its spindle head ( 55 , 75 ) for axial support on the axial pressure bearing ( 56 , 76 ), which is connected in a rotationally fixed manner to the threaded spindle ( 58 , 81 ), and
that the drive element ( 66 , 91 ) and the axial pressure ring ( 62 , 84 ) can be clamped together in a rotationally fixed connection during the relative axial movement of the drive element ( 66 , 91 ) to the threaded spindle ( 58 , 81 ) via a truncated cone-shaped cone section ( 72 , 105 , 109 ) of the drive element ( 66 , 91 ) and/or the axial pressure ring ( 62 , 84 ). 6. Spindle drive according to one of claims 2 to 5, characterized in that the frustoconical cone sections ( 17 , 2045 , 46 , 48 , 50 , 72 , 105 , 109 , 127 , 132 , 153 , 154 ) have a roughened or toothed surface. 7. Spindle drive according to one of claims 1 to 6, characterized in that the drive element ( 6 , 66 , 116 ) is screwed to the spindle head ( 1 , 55 , 115 ) via a threaded connection ( 8 , 10 , 73 , 117 , 119 ). 8. Spindle drive according to claim 7, characterized in that the threaded connection ( 8 , 10 , 73 , 117 , 119 ) of the drive element ( 6 , 66 , 116 ) and the spindle head ( 1 , 55 , 115 ) is left-handed, provided that the threaded spindle ( 2 , 58 , 130 ) is to be driven clockwise for tensioning a helical spring, or
that the threaded connection ( 8 , 10 , 73 , 117 , 119 ) of the drive element ( 6 , 66 , 116 ) and the spindle head is right-handed ( 1 , 55 , 115 ), provided that the threaded spindle ( 2 , 58 , 130 ) is to be driven anti-clockwise to tension a helical spring. 9. Spindle drive according to claim 1, characterized in that the drive element ( 200 ) and the threaded spindle ( 195 ) each have a toothing ( 214 , 215 , 217 , 218 ) in the region of their spindle head ( 197 ), which can be brought into engagement with one another by the axial movement of the drive element ( 200 ) relative to the threaded spindle ( 195 ). 10. Spindle drive according to claim 1, characterized in that the threaded spindle ( 160 ) has an axial pressure ring ( 161 ) in the region of its spindle head ( 164 ) for axial support on the axial pressure bearing, which is connected in a rotationally fixed manner to the threaded spindle ( 160 ), and
that the axial pressure ring ( 161 ) is provided with a toothing ( 184 ) which can be brought into engagement with a toothing ( 185 ) of the drive element ( 162 ) by the axial movement of the drive element ( 162 ) relative to the threaded spindle ( 160 ). 11. Spindle drive according to claim 9 or 10, characterized in that for the transmission of larger torques between the drive element ( 162 , 200 ) and the threaded spindle ( 160 , 195 ) in a preferred direction of rotation, the toothings ( 184 , 185 , 214 , 215 , 217 , 218 ) are designed like sawtooths.