GB1589260A

GB1589260A - Jack for a motor vehicle

Info

Publication number: GB1589260A
Application number: GB17805/78A
Authority: GB
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 1977-05-04
Filing date: 1978-05-04
Publication date: 1981-05-07
Also published as: FR2389570A1; IT1095727B; DE2720043A1; FR2389570B1; DE2720043C2; IT7822941A0

Description

(54) A JACK FOR A MOTOR VEHICLE (71) We, BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT, a German Body Corporate, of BMW-Haus, Petuelring 130, 8 Mtinchen 40, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to he performed, to be particularly described in and by the following statement: This invention relates to a jack for a motor vehicle, especially a passenger car, comprising a load-bearing column provided with a supporting foot or shoe, a load bearing arm movable along the bearing column by means of a screw or other drive member, and a load-bearing member provided on the end of the loadbearing arm which can be engaged with a receiving part on a motor vehicle body.

Jacks of this construction are, as a rule, provided with a support-forming projecting member or claw at the free end of the load-bearing arm which, in the working position of the jack, engages in a shallow socket on the underside of a sill or sill panel or in a bracket member on the underside of the sill or sill panel. The stability of these jacks and the way the forces are applied to the sill or sill panel are not satisfactory. Thus, for example, the jacks can all too easily rotate about a vertical axis whereby the vehicle body may be damaged or the jack may slide along the body or along the ground.

Where the motor vehicle rolls forward slightly, as can occur, for example, during changing of a tyre or wheel, then jacks provided with a supporting claw press hard against the bracket member allocated to them just at one point, thus producing a high local stressing of the body which necessitates specially reinforcing the engaged area. Engaging of the jack at a point and oblique positioning of the jack also carries with it the risk that the jack will slide along the vehicle body or along the aground.

While inserted-type jacks with a circular mandrel articulated to the load-bearing column do not have these drawbacks, they have other disadvantages. During lifting of the vehicle, a moment about a longitudinal axis is introduced into the car body in addition to the normal vehicle load-as a rule into the sill or sill panel.

Exacting welding of the socket into the sill panel is thus required (cf., for example, German Auslegeschrift DT-AS 11 61 162), which necessitates additional constructional outlay and, hence, additional costs because the sill panel must accommodate not just purely vertical loads but also torsional moments. If the sockets are taken as dose as possible to the outside of the body contours so as to reduce the torsional moments, then they detract stylistically. Since, as a rule, they need to be provided at four locations on the car body, the above-mentioned reinforcements of the sill panel must be provided at four locations giving a corresponding four-fold increase in weight.The sockets, which often form the starting points of premature corrosion, have the additional drawback that they may be blocked by dirt or frozen up in the winter, so that inserting the mandrel of the jack is made extremely difficult. If the mandrel is not inserted far enough, there is the danger that, when the vehicle is raised, the mandrel will slide out of the socket and the vehicle will descend until it strikes the ground.

The present invention therefore has as its aim the provision of a jack which, while avoiding the above mentioned drawbacks, ensures maximum safety and simple handling combined with simple construction.

This aim is achieved, in a jack of the construction described in the opening paragraph of the Specification, by arranging for the end of the arm to be underneath the receiving part of the motor vehicle body and the load-bearing member when the latter is engaged with the receiving part, and for the load-bearing member on the load-bearing arm to be so mounted as to be able to pivot about an axis extending transversely of the loadbearing arm.

As a consequence, during lifting of the motor vehicle, the load-bearing member can support itself on the receiving part of the vehicle body all the time with its entire contact-making area. The vertical force is transferred via the axis serving for the mounting of the load-bearing member on the load-bearing arm, that is to say, substantially underneath the sill, so that substantially no torsion moments are exerted on the sill. At the same time, the bearing member can balance out any rotation of the motor vehicle with respect to the bearing arm about a longitudinal axis.

In a further developement of the invention, the bearing member and the receiving part of the motor vehicle collaborate, when the jack is under load, to be twistproof about a vertical axis and to interlock positively in a longitudinal direction.

In accordance with a preferred embodiment, this can be achieved by the loadbearing member at the top having a contact-making upper surface having a shape corresponding approximately to the sector of a cylindrical shell, while the receiving part in the body has a correspondinglyshaped, downwardly-open, dish-shaped receiver. When the jack is under load, the load-bearing member is pressed into the dish-shaped receiver, thus making it impossible for the jack to turn about a vertical axis. Even when the jack is inclined somewhat obliquely in the longitudinal direction, the load-bearing member is still reliably supported against the sides of the dish-shaped receiver and cannot slide out of the receiver. On the other hand, there is no hindrance to a slight rotary movement of the load-bearing member in the dish-shaped receiver about a transverse axis of the vehicle.

Instead of the above-described dishshaped receiver, the receiving part could alternatively have a downwardly-open Ushaped cross-section with substantially vertical sides. The above-named advantages could then also be obtained. To facilitate reliable positioning of the loadbearing member in the dish-shaped receiver, the load-bearing member facing away from the load-bearing column at its end and can have a short spigot which can be inserted in a bore provided in an inner end-face boundary wall of the dishshaped receiver. In a particularly advantageous combination, a biased spring element acts between the bearing arm and the loadbearing member to urge the spigot of the load-bearing member downwards as far as an abutment stop.This spring ele ment, which may be formed from rubber or spring steel, ensures that the jack can be fitted into position only in a pre-deter mined inclination outwards with respect to the vehicle body. The angle of inclination is selected to be such that the loadbearing column, which necessarily moves towards the vehicle body with its upper end during lifting of the vehicle, nonetheless never touches and damages the body.

An example of a jack in accordance with the invention is shown in the accompanying drawings, in which: Figure 1 is a side view of the jack in the initial position when lifting movement begins; Figure 2 is a view corresponding to Figure 1, but when the vehicle has been raised by the jack: Figure 3 is a partial view taken from Figure 1 on a larger scale; and Figure 4 is a view in the direction of the arrow IV in Figure 3.

The jack illustrated as a whole in Fig.

ures 1 and 2 comprises a load-bearing column 1 provided with a supporting foot or shoe 2 at its lower end. A loadbearing arm 3 can be moved along the load-bearing column 1 by means of a screw mounted in the column, the loadbearing arm projecting under a motor vehicle body with its free end under the hollow sill 4 of the vehicle in the working position of the jack. The screw of the load-bearing column 1 is actuated by means of a hand crank 6 mounted in a driving head 5.

A load-bearing member 8 provided at the end of the load-bearing arm 3 and adapted to engage a receiving part 7 of the motor vehicle body is so mounted on the load-bearing arm 3 as to be pivotable about the axis 9 (see Figure 4) of a pivot pin 19 extending transversely to the loadbearing arm. Thus, the load-bearing member 8 always rests against the receiving part 7 over its entire contact-making surface even when the remainder of the jack changes its inclination with respect to the vehicle body in the course of vertical movement of the latter.

In the preferred example illustrated in the drawings, the load-bearing member 8 shown in Figures 3 and 4 has an upper contact-making surface 10 shaped approximately like a segment of a cylindrical shell, while the receiving part 7 of the vehicle body has a correspondingly-shaped, downwardly-open dish-shaped receiver 11.

The load-bearing member 8 can turn about the centre axis of the cylindrical shell surface but is nonetheless reliably secured in the longitudinal direction of the hollow sill 4 so that the jack cannot slide in this direction even when it is in an oblique position. The resting of the con tact-making surface 10 in the dish-shaped receiver 11 also gives the advantage that the jack is safeguarded against twist ing about a vertical axis while in the loaded state. As already mentioned, the receiving part 7 can alternatively have the cross-section of a downwardly-open Uprofile or an approximately dish-shaped cross-section to give the same above-named advantageous effects.

To provide a more reliable positioning of the load-bearing member 8 in the dishshaped receiver 11, the load-bearing member 8 is provided at its end facing away from the load-bearing column 1 with a short spigot 12 which can be inserted in a bore 13 provided in an inner end-face boundary wall 14 of the dish-shaped receiver 11. The spigot 12 is substantially coaxial with the axis of the above-described cylindrical shell surface. The external dimensions of the load-bearing member 8 are made larger than the spigot 12 so that the boundary wall 14 forms an abutment stop for the load-bearing member 8.

In order to safeguard the load-bearing member 8 also against sliding out of the dish-shaped receiver 11 in the direction of the outside of the vehicle, an abutment shoulder 15 for the load-bearing member 8 is provided on the outer end of the dish-shaped receiver 11. A clearance of several millimetres is provided between the end of the load-bearing member facing the load-bearing column 1 and the abutment shoulder 15 when the spigot is fully inserted so that the load-bearing member 8 can be introduced into the dish-shaped receiver 1 without great effort.

In a further development of the invention, a prestressed spring element 16 is provided which acts between the loadbearing arm 3 and the load-bearing member 8 so as to press the spigot 12 of the load-bearing member downwards until the load-bearing member 8 engages an abutment surface 17 on the bearing arm 3. This measure brings the important advantage that the jack can be fitted into position on the vehicle only in the correct inclination with respect to a vertical longitudinal plane. When the load-bearing member 8 lies inside the dishshaped receiver 11 and the spigot 12 is introduced in the bore 13, the upper end of the jack can be brought to the vehicle body in its fitted position only as far as the position shown in Figure 1. The strong spring element 16 strongly resists any closer approach than that.The precisely-located fitting position of the jack avoids any possibility that the driving head 5 might approach the outer skin of the vehicle body during the forced change in inclination of the jack following vertical movement of the vehicle body and thus dent the latter, as well as avoiding the need to fit the jack into position again with a different initial inclination. On the other hand, the above-specified adjustment of the load-bearing member 8 in the dishshaped receiver 11 and the bore 13 also always provides for a position of the jack which, in every phase of the vertical movement, ensures that the direction of the force exerted on the ground via the supporting foot or shoe 2 is all the time within the permissible non-slipping friction cone 18.

During cranking up of the load-bearing arm 3, a light pivoting of the load-bearing member 8 with respect to the load-bearing arm 3 against the action of the abovedescribed spring element 16 ensues without entailing a noticeably greater expenditure of strength. The spring element could be a rubber body or a helical spring.

In the preferred embodiment illustrated in the drawings, it is a straight-ended torsion spring-mounted on the pivot pin 19 for the load-bearing member 8 whose ends are supported on the load-bearing arm 3 and the load-bearing member 8 respectively.

As is shown more especially in Figure 4, the load-bearing member 8 preferably has a substantially U-shaped, downwardlyopen cross-section. Figures 3 and 4 of the drawing reveal further that the load-bearing member 8 is preferably fabricated from a punched-out sheet metal part. Consequently, the spigot 12 is hollow and open downwardly, but this does not impair its functioning.

In accordance with Figures 1 and 2 of the drawing, the jack has a tilting foot or shoe 2. To increase its stability, a foot plate 20 is arranged on the front end of the tilting foot 2 and is articulated to the tilting foot via a ball 21.

WHAT WE CLAIM IS:- 1. A jack for a motor vehicle, especially a passenger car, comprising a loadbearing column provided with a supporting foot or shoe, a load-bearing arm movable along the loadbearing column by means of a screw or other drive member, and a load-bearing member provided on the end of the arm which can be engaged with a receiving part on a motor vehicle body with the end of the arm underneath the receiving part and the loadbearing member, in which the load-bearing member is so mounted on the loadbearing arm as to be pivotable about an axis extending transversely of the loadbearing arm.

2. A jack according to claim 1 in conjunction with a motor vehicle, in which the load-bearing member and the receiv

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ing about a vertical axis while in the loaded state. As already mentioned, the receiving part 7 can alternatively have the cross-section of a downwardly-open Uprofile or an approximately dish-shaped cross-section to give the same above-named advantageous effects. To provide a more reliable positioning of the load-bearing member 8 in the dishshaped receiver 11, the load-bearing member 8 is provided at its end facing away from the load-bearing column 1 with a short spigot 12 which can be inserted in a bore 13 provided in an inner end-face boundary wall 14 of the dish-shaped receiver 11. The spigot 12 is substantially coaxial with the axis of the above-described cylindrical shell surface. The external dimensions of the load-bearing member 8 are made larger than the spigot 12 so that the boundary wall 14 forms an abutment stop for the load-bearing member 8. In order to safeguard the load-bearing member 8 also against sliding out of the dish-shaped receiver 11 in the direction of the outside of the vehicle, an abutment shoulder 15 for the load-bearing member 8 is provided on the outer end of the dish-shaped receiver 11. A clearance of several millimetres is provided between the end of the load-bearing member facing the load-bearing column 1 and the abutment shoulder 15 when the spigot is fully inserted so that the load-bearing member 8 can be introduced into the dish-shaped receiver 1 without great effort. In a further development of the invention, a prestressed spring element 16 is provided which acts between the loadbearing arm 3 and the load-bearing member 8 so as to press the spigot 12 of the load-bearing member downwards until the load-bearing member 8 engages an abutment surface 17 on the bearing arm 3. This measure brings the important advantage that the jack can be fitted into position on the vehicle only in the correct inclination with respect to a vertical longitudinal plane. When the load-bearing member 8 lies inside the dishshaped receiver 11 and the spigot 12 is introduced in the bore 13, the upper end of the jack can be brought to the vehicle body in its fitted position only as far as the position shown in Figure 1. The strong spring element 16 strongly resists any closer approach than that.The precisely-located fitting position of the jack avoids any possibility that the driving head 5 might approach the outer skin of the vehicle body during the forced change in inclination of the jack following vertical movement of the vehicle body and thus dent the latter, as well as avoiding the need to fit the jack into position again with a different initial inclination. On the other hand, the above-specified adjustment of the load-bearing member 8 in the dishshaped receiver 11 and the bore 13 also always provides for a position of the jack which, in every phase of the vertical movement, ensures that the direction of the force exerted on the ground via the supporting foot or shoe 2 is all the time within the permissible non-slipping friction cone 18. During cranking up of the load-bearing arm 3, a light pivoting of the load-bearing member 8 with respect to the load-bearing arm 3 against the action of the abovedescribed spring element 16 ensues without entailing a noticeably greater expenditure of strength. The spring element could be a rubber body or a helical spring. In the preferred embodiment illustrated in the drawings, it is a straight-ended torsion spring-mounted on the pivot pin 19 for the load-bearing member 8 whose ends are supported on the load-bearing arm 3 and the load-bearing member 8 respectively. As is shown more especially in Figure 4, the load-bearing member 8 preferably has a substantially U-shaped, downwardlyopen cross-section. Figures 3 and 4 of the drawing reveal further that the load-bearing member 8 is preferably fabricated from a punched-out sheet metal part. Consequently, the spigot 12 is hollow and open downwardly, but this does not impair its functioning. In accordance with Figures 1 and 2 of the drawing, the jack has a tilting foot or shoe 2. To increase its stability, a foot plate 20 is arranged on the front end of the tilting foot 2 and is articulated to the tilting foot via a ball 21. WHAT WE CLAIM IS:-

1. A jack for a motor vehicle, especially a passenger car, comprising a loadbearing column provided with a supporting foot or shoe, a load-bearing arm movable along the loadbearing column by means of a screw or other drive member, and a load-bearing member provided on the end of the arm which can be engaged with a receiving part on a motor vehicle body with the end of the arm underneath the receiving part and the loadbearing member, in which the load-bearing member is so mounted on the loadbearing arm as to be pivotable about an axis extending transversely of the loadbearing arm.

ing part of the motor vehicle collaborate with each other so as to be twist-proof about a vertical axis and to interlock positively in a longitudinal direction when the jack is under load.

3. A jack and motor vehicle according to claim 2, in which the load-bearing member has an upper contact-making surface shaped approximately like the section of a cylindrical shell, while the receiving part of the vehicle body has a correspondingly-shaped, downwardly-open dish-shaped receiver.

4. A jack and motor vehicle according to claim 3, in which the load-bearing member at its end remote from the loadbearing column has a spigot which can be inserted in a bore provided in an inner end-face boundary wall of the dish-shaped receiver.

5. A jack and motor vehicle according to claim 3 or claim 4, in which an abutment shoulder for the load-bearing member is formed on the outer end of the dish-shaped receiver.

6. A jack according to claim 4 or claim 5 where appendant thereto, in which a spring element acts between the loadbearing arm and the load-bearing member to press the spigot of the load-bearing member down as far as an abutment surface.

7. A jack according to claim 6, in which the spring element is a .straight- ended torsion -spring mounted on the journal for the load-bearing member, the ends of the spring being supported on the load-bearing arm and the load bearing member respectively.

8. A jack according to any preceding claim, in which the load-bearing member has a substantially U-shaped, downwardlyopen cross-section.

9. A jack according to claim 8, in which the load-bearing member is fabricated from a punched-out sheet-metal part.

10. A jack according to any preceding claim, in which the foot or shoe is mounted for tilting movement and has, at its front end, a foot plate which is articulated to the tilting foot via a ball.

11. A jack substantially as described herein with reference to the accompanying drawings.