DE202004006807U1 - Internal tensioner for tensioning a helical compression spring - Google Patents

Abstract

A replacement helical spring (2) forms part of an automotive shock absorber assembly and is presented for re-assembly in a non-tensioned condition. The spring is placed under tension for re-assembly by a compression tool (3) with an integral threaded spindle (4) with two end plates (7, 8) whose position relative to each other is varied by rotation. The plates further incorporated peripheral detents (30, 54) on their inner faces (24, 49) that engage with the spring tips.

Description

The invention relates to an internal clamp for Tensioning a helical compression spring according to the features in the preamble of claim 1.

From the prior art are in particular for the Automotive tensioner known for helical compression springs, with which these helical compression springs from corresponding recordings of the Fahrverks disassembled and can also be used again.

The DE 37 20 018 discloses a generic internal tensioner for helical compression springs which consists of a tensioning element which can be positioned centrally within a helical compression spring to be tensioned and whose effective length can be changed by means of a tensioning drive, and of two tensioning plates which are axially supported with respect to the tensioning element for contact with a spring turn of the helical compression spring. Both clamping plates have a central bore, the first clamping plate on the drive side being supported in the assembled state with a recess on the outside on a shoulder of the clamping element. The tensioning element comprises a threaded spindle in a threaded tube, a drive being provided at a 1st end of the tensioning element and fingers projecting radially outward at the opposite 2nd end. The second clamping plate to be mounted on the clamping element on the second end occupied by radial fingers has radially outward-facing recesses extending from the central bore, which form a common, approximately star-shaped opening with the central bore, so that this is occupied by radial fingers 2. End of the tensioning element can be passed through the opening formed thereby. At an angle to the outwardly projecting recesses of the second clamping plate, recesses are made in the outside of the second clamping plate, in which the radial fingers are held in a form-fitting manner when the internal clamp is in the assembled state.

Practical use shows that the assembly of this internal tensioner is complex and in particular threading of the second end of the tensioning element provided with the radial fingers is difficult to handle with regard to series assembly.

The radial fingers and the depressions enable a certain relative pivoting of the threaded tube to the second clamping plate. Due to the three-point principle Radial fingers rest in the recesses of the 2nd clamping plate however, lifting may occur when swiveling. This is a secure tensioning of a helical compression spring is not always guaranteed.

The spring windings of the helical compression spring are against radial sliding off the inside of the clamping plate through on the outer circumference the clamping plate provided collar-shaped collar secured.

This design leads to some chassis problems with dismantling and reassembling a helical compression spring, because the necessary space is not available.

The invention is based on from the state of the art - the Task based on an internal tensioner for tensioning a helical compression spring switch, which can be disassembled even in tight assembly rooms and assembly of a helical compression spring as well as for relative pivoting between the tension drive and that by the helical compression spring loaded clamping plates a perfect tensioning of a helical compression spring guaranteed.

This task is characterized by the in Part of claim 1 listed Features resolved.

Problems with tensioning a helical compression spring The invention now sees being able to effectively counter the clamping plates before that both clamping plates on the mutually facing inner sides with contact areas for spring turns are provided, the slopes in the circumferential direction of the clamping plate are adjusted to the pitch of the helical compression spring. Furthermore is in this context it is important that the contact patches too the central axes of the clamping plates by spring turns Ring beads are limited. That is, the spring coils not on the outer circumference the clamping plate can be gripped from the provided collar, but only on the inner circumference due to the positive engagement in the spring windings Ring beads are perfectly centered. This will both disassemble as well as assembly even in tight spaces of a chassis. The helical compression spring will slip off the clamping plates prevented.

The invention goes with both Advantage noticeable with an internal tensioner, in which the tension drive from a central threaded spindle, one along the threaded spindle displaceable threaded sleeve as well as a length segment the threaded spindle and protective sleeve encompassing the threaded sleeve, being the protective sleeve with the 1st clamping plate and the free end of the threaded sleeve the 2nd clamping plate can be coupled, as well as with an internal clamp with a threaded spindle, a pressure piece and a clamping nut, whereby a 2nd end of the threaded spindle with the 2nd clamping plate and the pressure piece with one 1. Clamping plates can be coupled.

According to the features of claim 2, a first clamping plate is provided on the circumferential side of a central opening for the tensioning drive on the outside facing away from the annular bead with a spherical segment-shaped cap for engaging a pressure surface adapted to it on a pressure piece of the tensioning drive. In this way, relative pivoting movements between the first clamping plate loaded by the helical compression spring and the pressure piece are taken into account.

The displacement of the central axis of the Ring bead on the 1st clamping plate to the common central axis of the 1. clamping plates and the central opening in the to the edge Recess facing away (claim 3) has the advantage that the internal tensioner in certain installation situations of a helical compression spring better can be applied.

Due to the adjustment of the contact areas the clamping plates on the pitch of the helical compression spring are sufficient according to the features of claim 4, if the edge-side segment-like recesses the clamping plate just over extend an angle of approximately 90 °. The Spring wire of a helical compression spring can thus be easily are transferred from one side to the other of the clamping plates. The areas delimiting the cutouts in the circumferential direction extend in radial planes, the first clamping plate through the central axis of the ring bead and run through the central axis of the second clamping plate.

In development of the invention according to claim 5, the pressure piece by a clamping nut on a threaded spindle of the clamping drive displaced.

Between the pressure piece and the An axial thrust bearing is provided, especially in the clamping nut, so that no significant frictional forces between the clamping nut and the pressure piece occur.

According to the features of the claim 6 is a second clamping plate with a transverse slot, the inner end shaped like a circle is designed, being on the outside facing away from the annular bead a calotte is provided which is composed of spherical section-shaped inner surfaces of different sizes, which from their configuration on spherical section-shaped surfaces a second end of the tension drive are aligned. In this way becomes an almost full surface Achievement of the 2nd end of the tensioning drive in the calotte and in all swivel positions of the tensioning drive relative to the 2nd Clamping plate. The 2nd end forms a pendulum head of the tensioning drive.

A particularly advantageous development of basic idea of the invention according to the features of claim 7 is that 2. The end of the tensioning drive is spherical and its flat end face on the circumference of straight edges and transition edges in the form of circular sections is limited. From the straight edges on the one hand and the transition edges in the form of circular sections on the other hand, spherical segment-shaped surfaces extend in Direction to the longitudinal axis of the tension drive. These surfaces are designed according to the invention that the radius of the surfaces between the straight edges and the longitudinal axis larger than the radius of the surfaces between the transition edges and dimensioned the longitudinal axis is. In contrast, the radius of all inner surfaces corresponds to the Calotte the radius of the surfaces between the straight edges and the longitudinal axis.

It is advantageous according to claim 8 further that the circumferential direction of the 2nd end of the tensioning drive measured length of the surfaces with the larger radius about six times the length of the surfaces with the smaller radius.

A non-rotatable embedding of the 2nd end of the tensioning drive in the calotte of the 2nd clamping plate according to the characteristics of claim 9 achieved in that the inner surfaces of the Dome with straight edges and circular section-shaped transition edges into that of the dome adjacent outside of the 2nd clamping plate open.

According to the features of the claim 10 are on a shaft-like length section of the tension drive adjacent to the second end two by a peripheral bead separate constrictions intended. The diameter of these constrictions is smaller than that Width of the cross slot in the 2nd clamping plate. The diameter the peripheral bead is larger than dimensioned the width of the transverse slot, but smaller than the diameter of the part-circular inner end of the transverse slot. In this way, the 2nd clamping plate easily between two spring turns of the helical compression spring introduced across become. Subsequently can then the tension drive in the longitudinal direction the helical compression spring can be moved until the 2nd end in the calotte of the 2nd clamping plate grips. Then you can use the The helical compression spring between the 1st and 2nd Clamping plates can be clamped.

To make it possible for a fitter at both ends of the tensioning drive tools for turning or for To be able to start counter provide the features of claim 11 that at the 1st end and / or At the 2nd end of the tensioning drive there are projections with flats are.

An appropriate design of the tension drive is ultimately characterized according to claim 12 in that the thickened 2nd end, the constrictions as well as the peripheral bead directly on the threaded spindle of the tensioning drive are provided. The threaded section of the threaded spindle is with a longitudinal groove to accommodate a slide spring as part of the with a clamping nut longitudinally displaceable pressure piece of the tensioning drive.

The invention is based on of an embodiment shown in the drawings. It demonstrate:

1 the individual parts of an internal clamp for tensioning a helical compression spring, partly in a schematic perspective, partly in a schematic view;

2 a front view of the inside of a 1st clamping plate of the inner tensioner of the 1 ;

3 a side view of the first clamping plate of the 2 seen in the direction of arrow III;

4 a vertical cross section through the representation of the 2 seen along the line IV - IV in the direction of the arrows IVa;

5 in the side view a longitudinal section of the inner tensioner of the 1 before coupling with a second clamping plate;

6 a plan view of the representation of 5 seen in the direction of arrow VI, partly in section;

7 a front view of the inside of the second clamping plate for coupling to the length section of the inner tensioner 5 and 6 ;

8th in perspective a view of the outside of the 2nd clamping plate and

9 a side view of the second clamping plate in the direction of arrow IX of 7 seen.

With 1 is in the 1 generally an internal tensioner for tensioning a helical compression spring 2 referred to, for example, for the disassembly and assembly of a helical compression spring 2 used, which forms part of a chassis of a motor vehicle.

The inner tensioner 1 consists of a tension drive 3 with threaded spindle 4 , Pressure piece 5 and tension nut 6 , as well as two with the tension drive 3 connectable clamping plates 7 . 8th together.

The from the 1 . 5 and 6 recognizable threaded spindle 4 has a threaded section over most of its length 9 with a rectangular thread 10 ( 6 ) on. At a 1st end 11 the threaded spindle 4 there is a head start 12 with key faces 13 for attaching a tool ( 1 ).

The threaded section 9 becomes parallel to the longitudinal axis on the circumference 14 the threaded spindle 4 from a longitudinal groove 15 enforced ( 1 and 5 ). The longitudinal groove 15 serves to engage a slide spring 16 that are in the pressure piece 5 located ( 1 ). The pressure piece 5 can over the threaded section 9 slide. It lies with a ring wreath 17 on a thrust bearing, which is in a sleeve-like length 18 the clamping nut 6 is used. The thrust bearing is not shown in detail. The tension nut 6 can over key areas 19 with the help of a suitable tool along the threaded section 9 be relocated.

At the other end has the pressure piece 5 a spherical segment-shaped pressure surface 20 for engaging in an appropriately configured spherical cap 21 circumference of a central opening 22 in the 1st clamping plate 7 ( 1 to 4 ). The calotte 21 flows into the outside 23 of the 1st clamping plate 7 , On the of the calotte 21 facing away from the inside 24 has the 1st clamping plate 7 a ring bead 25 for engaging a spring turn 26 , The ring bead 25 goes over a curved concave throat 27 in a footprint 28 over that protruding into the outer circumference 29 of the 1st clamping plate 7 transforms. The slope of the footprint 28 is the pitch of the helical compression spring 2 customized.

The recess on the edge 30 on the 1st clamping plate 7 is used to transfer the spring wire of the helical compression spring 2 from the inside 24 to the outside 23 , The common central axis of the 1st clamping plate 7 and the central breakthrough 22 is designated 57. As the 2 and 4 Beyond that, the central axis 58 of the annular bead 25 by the amount x to the common central axis 57 of the 1st clamping plate 7 and the central breakthrough 22 into the recess on the edge 30 opposite direction offset.

The recess 30 surfaces delimiting in the circumferential direction 59 extend in radial planes that define the central axis 58 of the ring bead 25 to cut. The recess runs in the circumferential direction 30 between the surfaces 59 over an angle α of 90 °.

The threaded section 9 the threaded spindle 4 goes according to the 1 . 5 and 6 in a shaft-like length section 31 about. This shows a constriction 32 to which there is a bulge 33 followed. Between the peripheral bead 33 and a thickened 2nd end 34 the threaded spindle 4 there is another constriction 35 , The diameter D of the constrictions 32 . 35 is the same size.

The 2nd end 34 is hemispherical. Its flat face 36 is on the circumference of straight edges 37 and circular section-shaped transition edges 38 limited. From the straight edges 37 from spherical segment-shaped surfaces extend 39 in the direction of the longitudinal axis 14 the threaded spindle 4 , Narrower spherical section surfaces 40 extend from the circular section-shaped transition edges 38 in the direction of the longitudinal axis 14 , The radius R of the surfaces 39 between the straight edges 37 and the longitudinal axis 14 is larger than the radius R _{1 of} the surfaces 40 between the transition edges 38 and the longitudinal axis 14 sized. The circumferential direction of the 2nd end 34 measured length of the surfaces 39 with the larger radius R corresponds to approximately six times the length of the surfaces 40 with the smaller radius R ₁ .

Face of the 2nd end 34 is a head start 41 with key faces 42 provided for attaching a tool.

With the thickened 2nd end 34 the threaded spindle 4 is the 2nd clamping plate 8th connectable from the 1 and 7 to 9 is more clearly recognizable. The 2nd clamping plate 8th has a transverse slot 43 , its inner end 44 is formed in a circular section. Circumferential side of the inner end 44 is neighboring the outside 45 a calotte 46 trained with the configuration of the surfaces 39 . 40 of the 2nd end 34 aligned spherical section-shaped wider inner surfaces 47 and in contrast narrower inner surfaces 48 Is provided. The radius of all interior surfaces 47 . 48 the calotte 46 corresponds to the radius R of the surfaces 39 between the straight edges 37 and the longitudinal axis 14 at the 2nd end 34 ,

Furthermore, the 1 . 7 and 9 recognize that the 2nd clamping plate 8th on that of the calotte 46 facing away from the inside 49 with a footprint 50 for a spring turn 26 the helical compression spring 2 is provided, the slope in the circumferential direction of the 2nd clamping plate 8th the pitch of the helical compression spring 2 is aligned. The footprint 50 is to the central axis 51 of the 2nd clamping plate 8th through one into a spring turn 26 gripping ring bead 52 limited. The footprint 50 goes without protrusion into the outer circumference 53 of the 2nd clamping plate 8th about.

The recess 54 in the outer circumference 53 of the 2nd clamping plate 8th serves to pass over the spring wire of the helical compression spring 2 from the inside 49 to the outside 45 , It extends over an angle β of 90 °. The recess 54 surfaces delimiting in the circumferential direction 60 run in radial planes that define the central axis 51 of the 2nd clamping plate 8th to cut.

The diameter D of the constrictions 32 . 35 at the shaft-like length section 31 the threaded spindle 4 is smaller than the width B of the cross slot 43 in the 2nd clamping plate 8th sized. The diameter D _{1 of} the peripheral bead 33 is larger than the width B of the cross slot 43 , but smaller than the diameter D _{2 of} the circular section-shaped inner end 44 of the cross slot 43 ( 7 ).

The surfaces 47 the calotte 46 open with straight edges 55 and the surfaces 48 with circular section-shaped transition edges 56 in the outside 45 of the 2nd clamping plate 8th ( 8th ).

For tensioning the helical compression spring 2 is the first clamping plate 7 between two spring turns 26 inserted diagonally. Then the threaded spindle 4 in the longitudinal direction of the helical compression spring 2 through the central breakthrough 22 of the 1st clamping plate 7 pushed and then with the pressure piece 5 as well as the clamping nut 6 Mistake. Then the 2nd clamping plate 8th also between two spring turns 26 the helical compression spring 2 threaded across, the constriction 32 in the cross slot 43 summarizes. Then the threaded spindle 4 be rotated in the longitudinal direction, the peripheral bead 33 through the inner end 44 of the cross slot 43 slides until the 2nd end 43 in the calotte 46 of the 2nd clamping plate 8th summarizes. Now you can turn the clamping nut 6 the helical compression spring 2 between the 1st clamping plate 7 and the 2nd clamping plate 8th axially tensioned, ie shortened. Through the ring beads 25 and 52 is the helical compression spring 2 securely fixed.

1

interior tensioner

2

Helical compression spring

3

tensioning drive

4

screw

5

Pressure piece

6

locknut

7

1. clamping plate

8th

Second clamping plate

9

Thread section v. 4

10

square thread

11

1st end of 4

12

Lead 11

13

Key faces 12

14

Longitudinal axis v. 4

15

Longitudinal groove in 4

16

Sliding spring in 5

17

Ring wreath 5

18

Longitudinal section v. 6

19

Key faces 6

20

Printing area 5

21

Calotte in 7

22

Breakthrough in 7

23

Outside v. 7

24

Inside v. 7

25

Ring bead on 24

26

spring coil

27

Throat 7

28

Footprint 7

29

Outer circumference 7

30

Recess 7

31

Longitudinal section v. 4

32

Constriction 31

33

Circumferential bead 31

34

2nd end of 4

35

Constriction 31

36

Front of v. 34

37

just edge

38

Transition edges

39

Surfaces 34

40

Surfaces 34

41

Lead 34

42

Key surfaces 41

43

Cross slot in 8th

44

inner end v. 43

45

Outside v. 8th

46

Calotte in 45

47

Inner surfaces v. 46

48

Inner surfaces v. 46

49

Inside v. 8th

50

Footprint 49

51

Central axis v. 8th

52

Ring bead on 49

53

Outer circumference 8th

54

Recess 8th

55

straight edges 47

56

Transition edges v. 48

57

Central axis v. 7

58

Central axis v. 25

59

Areas of 30

60

Areas of 54

B

Width of 43

D

Diameter of 32 . 35

D1

Diameter of 33

D2

Diameter of 44

R

Radius of 39

R1

Radius of 40

α

Angle between 59

ß

Angle between 60

Claims (12)

Internal tensioner for tensioning a helical compression spring ( 2 ), which in particular forms part of a chassis of a motor vehicle, which has a tensioning drive ( 3 ) with integrated threaded spindle ( 4 ) and two clamping plates that can be moved relative to each other ( 7 . 8th ) that has cutouts on the edge ( 30 . 54 ) are provided, characterized in that the clamping plate ( 7 . 8th ) on the inside facing each other ( 24 . 49 ) with the pitch of the helical compression spring ( 2 ) adapted contact areas ( 28 . 50 ) are provided, which protrude without protrusion into the outer circumference ( 29 . 53 ) the clamping plate ( 7 . 8th ) pass, but to the central axes ( 57 . 51 ) the clamping plate ( 7 . 8th ) through in spring coils ( 26 ) positively engaging ring beads ( 25 . 52 ) are limited. Inner clamp according to claim 1, characterized in that a first clamping plate ( 7 ) circumference of a central opening ( 22 ) for the tension drive ( 3 ) on the ring bead ( 25 ) facing away from the outside ( 23 ) with a spherical segment-shaped spherical cap ( 21 ) to engage a pressure surface adapted to it ( 20 ) on a pressure piece ( 5 ) of the tension drive ( 3 ) is provided. Inner clamp according to claim 2, characterized in that the central axis ( 58 ) of the ring bead ( 25 ) on the 1st clamping plate ( 7 ) to the common central axis ( 57 ) of the 1st clamping plate ( 7 ) and the central breakthrough ( 22 ) in the recess on the edge ( 30 ) direction is offset. Inner clamp according to one of claims 1 to 3, characterized in that the segment-like recesses ( 30 . 54 ) extend over an angle (α, β) of approximately 90 °. Inner clamp according to one of claims 2 to 4, characterized in that the pressure piece ( 5 ) with a clamping nut ( 6 ) on a threaded spindle ( 4 ) of the tension drive ( 3 ) is relocatable. Inner clamp according to one of claims 1 to 5, characterized in that a second clamping plate ( 8th ) with a cross slot ( 43 ) is provided, the inner end ( 44 ) is designed in the form of a circular section, on which the bead ( 52 ) facing away from the outside ( 45 ) a calotte ( 46 ) is provided, which consists of spherical segment-shaped inner surfaces ( 47 . 48 ) of different sizes, which, based on their configuration, have spherical section-shaped surfaces ( 39 . 40 ) at a 2nd end ( 34 ) of the tension drive ( 3 ) are aligned. Inner tensioner according to claim 6, characterized in that the second end ( 34 ) of the tension drive ( 3 ) hemispherical and its flat face ( 36 ) on the circumference of straight edges ( 37 ) and circular section-shaped transition edges ( 38 ) from which the spherical segment-shaped surfaces ( 39 . 40 ) in the direction of the longitudinal axis ( 14 ) of the tension drive ( 3 ), the radius (R) of the surfaces ( 39 ) between the straight edges ( 37 ) and the longitudinal axis ( 14 ) larger than the radius (R1) of the surfaces ( 40 ) between the transition edges ( 38 ) and the longitudinal axis ( 14 ) is dimensioned and that the radius of the inner surfaces ( 47 . 48 ) the calotte ( 46 ) the radius (R) of the surfaces ( 39 ) between the straight edges ( 37 ) and the longitudinal axis ( 14 ) corresponds. Inner clamp according to claim 6 or 7, characterized in that the circumferential direction of the 2nd end ( 34 ) of the tension drive ( 3 ) measured length of the surfaces ( 39 ) with the larger radius (R) about six times the length of the surfaces ( 40 ) with the smaller radius (R1). Inner clamp according to one of claims 6 to 8, characterized in that the inner surfaces ( 47 . 48 ) the calotte ( 46 ) in the 2nd clamping plate ( 8th ) with straight edges ( 55 ) and circular section-shaped transition edges ( 56 ) in that of the calotte ( 46 ) adjacent outside ( 45 ) of the 2nd clamping plate ( 8th ) lead to. Inner clamp according to one of claims 6 to 9, characterized in that on a shaft-like length section ( 31 ) of the tension drive ( 3 ) adjacent to the 2nd end ( 34 ) two by a peripheral bead ( 33 ) separate constrictions ( 32 . 35 ) are provided, the diameter (D) of which is smaller than the width (B) of the transverse slot ( 43 ) in the 2nd clamping plate ( 8th ), the diameter (D1) of the peripheral bead ( 33 ) greater than the width (B) of the cross slot ( 43 ), but smaller than the diameter (D2) of the circular segment-shaped inner end ( 44 ) of the transverse slot ( 43 ) is. Inner clamp according to one of claims 1 to 10, characterized in that at the 1st end ( 11 ) and / or at the 2nd end ( 34 ) of the tension drive ( 3 ) Projections ( 12 . 41 ) with key surfaces ( 13 . 42 ) are provided. Inner tensioner according to claim 10 or 11, characterized in that the thickened 2nd end ( 34 ), the constrictions ( 32 . 35 ) as well as the bulge ( 33 ) directly on the threaded spindle ( 4 ) of the tension drive ( 3 ) are provided and the threaded section ( 9 ) of the threaded spindle ( 4 ) with a longitudinal groove ( 15 ) to accommodate a slide spring ( 16 ) as part of a with a clamping nut ( 6 ) along the thread section ( 9 ) displaceable pressure piece ( 5 ) is provided.