FR2732324A1 - VEHICLE JACK - Google Patents

Abstract

The invention relates to a vehicle jack (1) comprising a support leg (2) and a lifting arm (4) articulated at one end on the latter, provided at the other end with a head (5) to engage under the vehicle to be lifted, and a control screw (6) to rotate the lifting arm. The control screw bears axially on the jack head when the latter is working empty and the control screw is actuated in the direction tending to fold the jack.

Description

The present invention relates to a vehicle jack comprising a leg

  support and a lifting arm articulated on the support leg, to be rotated by means of a control screw to lift the vehicle. A jack of this type, commonly called a "Y jack", is described, for example, in patent application EP-0 565 801. In this known jack, the control screw is engaged in a part forming a nut received in an articulated manner in support leg recesses. The control screw has a stepped head axially bearing against a ball stop when the jack is loaded and the control screw works in traction to move the lifting arm. balls rests in a yoke articulated on the lifting arm. A stop sleeve axially maintains the shouldered head in abutment on the ball stop when the jack is working empty and the control screw is actuated in the direction tending to

fold up the jack.

  An object of the present invention is to provide an improved jack of simplified construction, of the type comprising a support leg and a lifting arm pivotally mounted at one end on the latter, provided at the other end with a engage under the vehicle to be lifted, and a control screw to move the lifting arm, the control screw turning in a nut-forming part pivotally mounted on the

  supporting leg and being connected at one end to the lifting arm.

  It achieves this by the fact that the jack head is arranged in alignment with the control screw so that the latter is axially supported on the jack head at least during the operation of the jack when the latter is working empty and that the control screw is actuated in the

sense tending to fold the jack.

  Advantageously, the jack head is articulated on the lifting arm around an axis of rotation perpendicularly cutting the longitudinal axis

of the control screw.

  Advantageously, the control screw has a stepped head resting axially on a thrust ball bearing at least during operation.

  jack when it is loaded.

  Advantageously, the thrust ball is housed in a yoke

articulated on the lifting arm.

  Advantageously, the yoke is articulated on the lifting arm

  around the same axis of rotation as the jack head.

  Advantageously, the nut-forming part being received in recesses in the support leg, the nut-forming part is retained in the latter by a retaining element integral with the latter and engaged in

  at least one curvilinear lumen of the supporting leg.

  Other features and advantages of the present invention

  will appear on reading the detailed description which follows, of a

  non-limiting example of an embodiment of the invention, and on examining the appended drawing in which: FIG. 1 is a side view of a jack according to the invention, in the deployed position for lifting a vehicle, - Figure 2 is a schematic section in a plane containing the axis of rotation of the control screw, showing certain components of the jack shown in Figure 1, - Figure 3 is a side view of the head of the jack shown in Figure 1, - Figure 4 is a front view of the head shown in Figure 3, - Figure 5 is a top view of the head shown in Figure 3, - Figure 6 is a front view of the jack screed shown in Figure 1, - Figure 7 is a top view of the screed shown in Figure 6, - Figure 8 is a side view of the screed shown in Figure 6, - Figure 9 is a side view of the jack lifting arm shown in Figure 1, - Figure 10 is a top view of the lifting arm shown in FIG. 9, FIG. 11 is a section along the cutting line XI in FIG. 9, FIG. 12 is a section along the cutting line XII in FIG. 9, FIG. 13 is a section along the section line XIII in FIG. 9, - FIG. 14 shows, flat, one end of the sheet serving to make the lifting arm, - FIG. 15 is a side view of the part forming the jack nut shown in FIG. 1, FIG. 16 is a top view of the part forming the nut represented in FIG. 15, - FIG. 17 is a section along the section line XVII of FIG. 16, -Figure 18 is a section along the section line XVIII of Figure 16, -Figure 19 is a front view of the nut forming part shown in Figure 15, - Figure 20 shows, in side view, the jack shown in Figure 1 in the folded position, - Figure 21 is a top view of the jack shown in the a Figure 20, - Figure 22 shows, on an enlarged scale, the head of the jack when the latter is in the deployed position, - Figure 23 shows, on an enlarged scale, the head of the jack when the latter is in the folded position, - the Figure 24 is a side view of the support leg of the jack shown in Figure 1, - Figure 25 is a front view of the support leg shown in Figure 24, - Figure 26 is a top view of the support leg shown in Figure 24, - Figure 27 is a section along the section line XXVII of Figure 24, - Figure 28 is a section along the section line XXVIII of Figure 24, - the Figure 29 shows, flat, one end of the sheet used to make the

supporting leg.

  The jack 1 shown in the figures has a support leg

  2 intended to rest, by a lower end forming a foot 3, on the ground.

  A lifting arm 4 is articulated at one end on this support leg 2, and supports at the other end a head 5 intended to come into contact with the vehicle to be lifted. A control screw 6, on which a drive handle 7 is articulated at one end, makes it possible to move the lifting arm 4 to raise or lower the head S. The lifting arm 4 is articulated on the leg support 2 around an axis of rotation X perpendicular to the plane of Figure 1. The head 5 of the jack 1 is articulated on the lifting arm 4 around an axis of rotation Y parallel to the axis X. The screw control 6 extends along a longitudinal axis W parallel to the plane of Figure 1, perpendicularly cutting the axis X. It crosses a piece forming a nut 8 hinged on the support leg 2 about an axis of rotation Z intersecting the W axis and parallel to the X axis. The jack 1 is symmetrical with respect to a plane of symmetry containing the W axis and perpendicular to the X axis.

  The head 5 of the jack 1 is shown in isolation in FIGS. 3 to 5.

  It is preferably made of plastic, and comprises a body 50 crossed by a cylindrical bore 51 of revolution around the axis Y, for

  the passage of a hinge pin 98 of the head 5 on the lifting arm 4.

  Two fingers 52, 53 extend the body 50 above (when the jack is in the deployed lifting position of a vehicle as shown in FIG. 1) and define between them a groove 54, opening upwards, for engagement of the head 5 on a weld bead or a rebate of the vehicle body, projecting downwards, or on any other part of the vehicle provided for this purpose. The respective surfaces 540, 541 of the fingers 52, 53, facing each other, are plane and parallel. The head 5 has stop surfaces 520, the role of which will be explained below, located at the base of the finger 52 and extending, flat, forming an angle of 44 30 'with the plane of the surfaces 540 and 541 The lower ends of these stop surfaces 520 have been referenced 521. The body 50 also has a cylindrical surface 55 of

  revolution around the Y axis, extending over an angular sector of 60.

  The control screw 6 has a helical thread 60 extending along the axis W, engaged in the part forming the nut 8, and comprises at one axial end a shouldered head 61. It is provided at the opposite axial end with a tip 66 on which the handle 7 is articulated, about an axis of rotation perpendicularly cutting the axis W. The shoulder head 61 rests by its axial end edge 63 against the surface 55 of the head 5 and by its shoulder , referenced 64, on a ball stop 62 bearing on a yoke 9. This ball stop 62 comprises, in a manner known per se, two rings 62a, 62b of axis W, defining paths of

  bearing for balls 62c interposed between the rings 62a, 62b.

  The yoke 9 is shown in isolation in Figures 6 to 8. It has two flanges 90, planes and parallel to each other, joined by a base 91. The latter extends perpendicular to the plane of the flanges 90. Holes 92 of axis Y are provided on the flanges 90 for the passage of the aforementioned articulation pin 98, and the rotational mounting of the yoke 9 on the lifting arm 4 around the axis Y. The base 91 is crossed by a bore 93 for the passage of the control screw 6. The ring 62b of the ball bearing 62 rests against the face 910 of the base 91 facing towards the interior of the flanges 90. The latter are perforated at 94 as shown in FIG. 8 to make saving material. They have, observed in the direction of the Y axis, a generally triangular outline, delimited laterally by two rectilinear edges 95 converging in approach to the Y axis, these edges 95 being joined at their end opposite to the base 91 by an edge. 96 in an arc, centered on the Y axis, and connecting to the base 91 by rectilinear edges 97, parallel to the W axis.

  FIGS. 9 to 14 show the lifting arm 4 in isolation.

  The latter is preferably produced by stamping, cutting and bending a sheet to form a metal profile elongated in the direction of a longitudinal axis V perpendicular to the axes X and Y. This profile has a cross section having the general shape of a U, as shown more particularly in Figures 1 1 to 13. It has two wings 40 joined by a back 41 extending generally perpendicular to the wings 40. Oblong recesses 42 drawn from stamping extend parallel to the axis V on the wings 40 to stiffen the profile. These recesses 42

  protrude into the interior space of the profile located between the wings 40.

  An oblong recess 43, projecting inward, is made on the back 41 for the same purpose. The wings 40 are pierced at a longitudinal end, at 44, for the passage of the aforementioned pin 98 and the rotational assembly of the head 5, the yoke 9 and the lifting arm 4. These holes 44 are made at one end longitudinal of the recesses 42. The wings are pierced at the opposite longitudinal end, at 46, for the passage of a pin 28 of axis X serving for the articulation of the lifting arm 4 on the support leg 2. These holes 46 are made on circular stampings 47 projecting towards the outside of the profile, as shown more particularly in FIG. 12. These circular stampings 47 are located in the extension of the recesses 42, leaving a gap 470 with the latter as shown on Figure 9. The back 41 is extended, at the end of the lifting arm 4 articulated on the support leg 2, by a wall 48 extending obliquely between the wings 40 and forming a spacer. The wall 48 results from a cutting and a folding of the sheet metal used to produce the profile, as illustrated in FIG. 14. The longitudinal ends of the wings 40 have at the end articulated on the support leg 2 a generally triangular profile, observed in the direction of the X axis. This profile is delimited by two orthogonal rectilinear edges 401, 402 joined by an edge in an arc of a circle 403 centered on the X axis. After folding, the wall 48 s extends in the plane of the edges 401 and forms with the back 41 a dihedral angle at the top 238. The nut forming part 8 is shown in isolation in FIGS. 15 to 19. The latter is preferably made of plastic. It comprises a body 80 traversed along the axis W by a tapping 81 adapted to receive the threaded body 60 of the control screw 6. Lateral parts 82 form protrusions on either side of the body 80 for the articulation of the piece forming a nut 8 on the support leg 2. These lateral parts 82 are delimited radially, on the outside, by cylindrical surfaces of revolution around the axis Z, and axially by end sections 83 which are planar and perpendicular to the axis Z. The piece forming a nut 8 also comprises two tabs 84 crossed by bores 85 of axis T parallel to the axis Z, for mounting means for retaining the piece forming a nut 8 on the leg of support 2, as will be explained below. The lugs 84 are connected to the body 80 by providing annular grooves 86 centered on the Z axis with the cylindrical surfaces 82. The dihedral from the top of the Z axis, delimited by the plane perpendicular to the W axis and by the plane containing the axis T, is of angle at

summit 60.

  FIGS. 24 to 29 show the support leg 2 in isolation.

  The latter is preferably produced by stamping, cutting and bending a sheet to form an elongated profile along a longitudinal axis G perpendicular to the axis Z. This profile has a cross section having

  the general shape of a U, comprising two wings 20 joined by a back 21.

  Each wing 20 has an oblong recess 22 drawn from stamping, projecting into the interior space of the profile located between the wings 20, and

intended to stiffen the profile.

  The foot 3 is formed by cutting and folding as illustrated in FIG. 29. More specifically, the foot 3 has a first planar wall 30 connected to the back 21 by a fold line 31 and forming, in the assembled position of the jack, an angle 43 with the back 21 as shown in Figure 24. This wall 30 is extended downwards by a flat wall 32 intended to serve as a bearing surface on the ground. The fold line extending at the junction of the walls 30 and 32 has been referenced 33. The dihedral having the fold line 33 at the top and delimited by the planes of the walls 30 and 32 has an angle at the top of 142. The wall 30 widens away from the back 21 until it reaches a width approximately twice that of the back 21 at the fold line 33. The width of the wall 32 is constant. The latter rests, by its face opposite to that coming to bear on the ground, against the

wing edge 20.

  The free edges 23 of the wings 20 are curved outwards as shown more particularly on the cross sections of Figures 27 and 28, for the purpose of stiffening the profile. The cross section of the support leg 2 is generally constant from the foot 3 to about half the height of the support leg 2, where the width of the wings 20 increases and becomes maximum at the level of a bore. 24 serving for the passage of the pivot 28 of articulation of the lifting arm 4. The width of the wings 20 then decreases up to the height of the upper longitudinal ends 26 of the recesses 22, where the wings 20 form notches 211. The back 21 s' interrupts at the height of these notches 211. The width of the wings 20 increases above the notches 211 in the direction of the upper end of the support leg 2, situated opposite the foot 3, up to recesses 25 formed on the wings 20, serving as articulation bearings around the axis Z to the nut-forming part 8. On the portion of the wings 20 extending between the upper ends 26 of the oblong recesses 22 and the plane containing the axis Z and perpendicular to the long axis itudinal G, are provided curvilinear lights 27. The latter participate in the retention of the part forming a nut in the recesses 25. The back 21 forms, at the height of the holes 24, a dihedral projecting outwards, of angle at the top 152. The edges 23 extend rectilinearly, parallel to the recesses 22, from their lower end bearing against the wall 32 to the plane containing the axis Z and perpendicular to the axis G. The edges 23 extend beyond this plane, in arcs of a circle 230 and terminate in rectilinear portions 231 perpendicular to the axis G. The recesses 25 have, as shown in FIG. 24, edges in the shape of a semicircle 250, centered on the axis Z and radius adapted to that of the cylindrical surfaces 82. These semicircular edges 250 are extended below by rectilinear edges 251 perpendicular to the longitudinal axis G, and above, by rectilinear edges 252 extending parallel to the edges 251 but over a distance corresponding to approximately a quarter of the length of the straight edges 251. The edges 250, 251 and 252 are curved towards the interior space situated between the wings 20 to form bearing surfaces e 253 coming into contact with the cylindrical surfaces 82 of the nut-forming part 8. These bearing surfaces 253 are of generatrix parallel to the axis Z. The recesses 25 define grooves the bottom of which is formed by the semicircular edges 250 and whose opening width, that is to say the distance separating the straight edges 251 and 252,

  is at least equal to the diameter of the semicircular edges 250.

  Each curvilinear lumen 27 extends along a median line K in an arc of a circle situated at the same distance from the axis Z as the distance separating the latter and the axis T of the bores 85, and has at its longitudinal ends half edges -circulars 270 and 271. The dihedral having for

  vertex the Z axis, delimited by the planes containing the axes of the half-edges

  circular 270 and 271, is at an angle at the top 115. The plane containing the axis Z and the axis of the semicircular holes 270 extends parallel to the edges

straight 251.

  The mounting of the nut forming part 8 on the support leg 2 is easily carried out, by engaging the nut forming part 8 provided with the control screw 6 in the recesses 25, until the cylindrical surfaces 82 stop against the edges. semicircular 250. The introduction of the nut forming part 8 can be carried out by a simple translational movement in a direction perpendicular to the axis Z and is suitable for mechanized execution. The holes 85 of the tabs 84 of the piece forming a nut 8 are then positioned opposite the curvilinear slots 27. A rivet 89 is introduced into the curvilinear slots 27 and the holes 85 for retaining the piece forming a nut 8 on the support leg 2 After the riveting operation, the rivet 89 comes to bear axially at its axial ends on the surface

  external 200 of the wings 20 bordering the curvilinear lights 27.

  The operation of jack 1 is as follows.

  In the folded state, as shown in FIGS. 20, 21 and 23, the lifting arm 4 folds down between the wings 20 of the support leg 2, the head 5 abutting by the stop surfaces 520 on the curved edges 23. In the folded position of the jack 1, the end edge 63 of the control screw 6 rests on the end of the cylindrical surface 55 adjacent to the finger 53, as shown more particularly in Figure 23. The handle 7 can advantageously fold back against the external surface of a wing 20 as shown in FIG. 21. The rivet 89 abuts against the semi-circular edges 271. To unfold the jack 1, the user turns the handle 7 and drives in rotation of the control screw 6 about the axis W. The longitudinal displacement of the control screw 6 which results from its rotation in the internal thread 81 causes the lifting arm 4 to pivot clockwise in FIG. 1 and the displacement up the head 5. The rotation of the arm of the evage 4 is accompanied by a displacement of the rivet 89 in the

  curvilinear lights 27 until the latter stops against the half edges

  circular 270. The jack 1 is then in its maximum lifting position and the control screw is subjected to tensile forces when the jack is loaded. The surfaces 540 and 541 are normally oriented vertically in the lifting position of the vehicle, as shown in FIG. 1, and the front surface 63 of the ball bearing 62 is then located at the end of the cylindrical surface 55 farthest from the fingers 52 and 53. Any additional rotation of the head 5 anti-clockwise is prevented by abutment of the lower ends 521 of the stop surfaces 520 against the end edges 201 of the wings 20, as illustrated in FIG. 22 more particularly.

  To fold the jack 1, the user turns the control screw 6.

  As long as the jack 1 lifts the vehicle, that is to say works under load, the control screw 6 works in traction and the ball stop 62 is stressed axially in compression. When the jack has been folded enough and no longer lifts the vehicle, that is to say it works when empty, the control screw 6 comes to bear axially by the end edge 63 against the surface 55 of the head 5. This ensures the drive of the lifting arm, without using a stop sleeve engaged on the control screw as is the case on the

known jacks.

  Finally, a jack according to the invention has a space requirement in the folded position that is sufficiently small for its housing in a spare wheel rim, in particular thanks to the particular arrangement of the control screw 6 on the jack 1. The assembly of the jack is easy to perform and can be executed by a robot. The positioning of the axes of rotation X, Y and Z, in particular the intersection of the axes W and Y is advantageous from the kinematic point of view. The rivet 89 increases the safety of use of the jack by preventing the wings of the support leg 2 from moving apart. A stop sleeve is not necessary and the free rotation of the head 5 on the lifting arm 4 reduces the risk of damage to the vehicle body in the event of

improper positioning of the jack.

Claims (8)

  1 / vehicle jack (1) comprising a support leg (2) and a lifting arm (4) pivotally mounted at one end on the latter, provided at the other end with a head (5) to be engaged under the vehicle to be lifted, a control screw (6) for moving the lifting arm (4), connecting the latter and the support leg, turning in a nut-forming part pivotally mounted on the support leg and connected at one end to the lifting arm (4), characterized in that the jack head (5) is arranged in alignment with the control screw (6) so that the latter is axially supported on the jack head at least during operation of the jack when the latter is working empty and the control screw is actuated in the direction tending to fold up the jack.   2 / Jack according to claim 1, characterized in that the jack head (5) is articulated on the lifting arm (4) about an axis of rotation (Y) perpendicularly cutting the longitudinal axis (W) of the control screw (6).   3 / Jack according to one of claims 1 and 2, characterized in that   the control screw has a stepped head resting axially on a thrust ball bearing (62) at least during the operation of the jack when the jack is in charge.   4 / Jack according to claims 2 and 3, characterized in that the   thrust ball bearing (62) is housed in a yoke (9) articulated on the lifting arm.   / Jack according to claim 4, characterized in that the yoke is articulated on the lifting arm around the same axis of rotation (Y) as the head jack.   6 / Jack according to one of claims 1 to 5, the part forming a nut   (8) being received in recesses (25) of the support leg (2), characterized in that the nut forming part is retained in the latter by a retaining element (89) integral with the nut forming part and engaged in at   minus a curvilinear lumen (27) of the support leg (2).   7 / jack according to claim 6, characterized in that each recess (25) of the support leg (2) receiving the piece forming a nut (8) constitutes a groove the bottom of which is delimited by a semi-circular edge (250 ) and whose opening width is greater than or equal to the diameter of said semicircular edge.   8 / jack according to claim 7, the support leg (2) having the general shape of a U-shaped cross section profile, characterized in that said retaining element is a rivet (89) axially supported on   the outer faces of the two wings (20) of the profile.   9 / jack according to claim 8, the support leg (2) having the general shape of a U-shaped cross section profile, characterized in that the wall of the wings of said profile bordering said recesses (25) is curved to increase the contact surface of the part forming nut (8).