Abstract:
A scissor car jack includes a spindle, a base, a support head, a cross-member, and a spindle support with a threaded bore for holding the spindle. The base and support head are rotatably connected to the crossmember and the spindle support by way of a respective support arm, and wherein the support arms are connected with one another in the area of the base and the support head and/or in the area of the crossmember and the spindle support, and the spindle is coupled to the crossmember and the spindle support so that when the spindle is rotated, the distance between the spindle support and the crossmember can be changed. The length of the support arms can be changed telescopically and can be locked in the extended state by way of locking pins so that the scissor jack can be collapsed into a smaller volume, in particular for purposes of stowage.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a scissor jack with a spindle, a foot, a carrying head, a crossmember, and a spindle mount. The spindle mount has a bore with an internal thread for receiving the spindle. The foot and the carrying head are reotatably connected to the crossmember and the spindle mount by way of a respective carrying arm. The carrying arms are coupled to one another in the region of the foot and of the carrying head and/or in the region of the crossmember and of the spindle mount. The spindle is coupled to the crossmember and the spindle mount, so that, upon rotation of the spindle, it is possible to change the distance between the spindle mount and the crossmember. 
     It is known to use a car jack to raise passenger vehicles in order to change tires. Since the trunk of a passenger vehicle, nowadays, is packed full with various articles and pieces of equipment, a car jack should also have small dimensions in order to allow it to be accommodated. It is, of course, imperative here for the reliable functioning of the car jack not to be impaired. DE 10 2004 003 177 B4 discloses a scissor car jack in which the kinematic points are connected to single-piece carrying arms. In the collapsed state, the aforementioned car jack has a maximum length which is proportional to the lifting height. In the case of the lifting heights being relatively great, this car jack is difficult to accommodate in the trunk of a passenger vehicle. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the present invention is thus to provide a scissor car jack which can be changed into a relatively small transporting volume for stowage purposes without the functional reliability being impaired. 
     This object is achieved by a car jack as claimed. 
     According to the invention, the scissor car jack has a spindle, a foot, a carrying head, a crossmember and a spindle mount with a bore with an internal thread for receiving the spindle. The foot and the carrying head are connected in a rotatable manner to the crossmember and the spindle mount by means of a respective carrying arm, wherein the carrying arms are coupled to one another in the region of the foot and of the carrying head and/or in the region of the crossmember and of the spindle mount. Furthermore, the spindle is coupled to the crossmember and the spindle mount, so that, upon rotation of the spindle, it is possible to change the distance between the spindle mount and crossmember. The carrying arms can advantageously be changed telescopically in length, so that the scissor car jack can be collapsed to a relatively small volume without impairing the functional reliability, so that the jack can be stowed in a space-saving manner in the trunk of a vehicle. 
     If the spindle has a pulling direction, a pushing direction and a direction of rotation along its longitudinal axis, then it is particularly advantageous if the spindle at least in the extended state, in order to be reduced in size, is not coupled to the crossmember in the pushing direction. When the telescopically changeable carrying arms are being collapsed, the spindle can thus yield in the pushing direction, so that the scissor car jack is straightforwardly reduced in volume. 
     It is likewise advantageous if the spindle has a length which is substantially smaller than, or equal to, double the length of a carrying arm in the collapsed state. This makes it possible to achieve a very small stowage volume for the scissor car jack since the spindle, in the collapsed state, does not project beyond the spindle mount or the crossmember. 
     In order to reduce the stowage volume, it is particularly advantageous if the crossmember has a guide tube for at least partially receiving the spindle, wherein the guide tube is mounted in the crossmember such that it can be rotated coaxially with the longitudinal axis of the spindle, in particular by way of a ball bearing, and the spindle can be displaced along its longitudinal axis, within the guide tube, into an operating position and a stowage position, wherein the spindle, at least in the operating position, is coupled to the guide tube in the pulling direction and the direction of rotation, so that rotation of the guide tube makes it possible to change the distance between the spindle mount and crossmember. This largely rules out the situation where the spindle projects beyond the spindle mount in the collapsed state. 
     In this respect, it is likewise advantageous if the spindle, in the second stowage position, does not project beyond that end of the guide tube which is directed away from the spindle, and this helps the stowage volume of the scissor car jack to be as small as possible. 
     The carrying arms advantageously comprise a first part and a second part which can be displaced one inside the other, so that the width of the scissor car jack can be reduced essentially by half. 
     In order for loads to be raised in a reliable manner, it is particularly advantageous if the carrying arms, in the extended state, can be locked in particular by means of a locking element, so that an unintended collapsing operation of the carrying arms is ruled out. 
     In order to ensure easy handling during locking and unlocking, it is advantageous if the locking element is a locking pin which in the extended state, in the region of overlap between the first part and the second part, these both having at least one bore in each case, can be introduced through the congruent bores, which are located one above the other, for locking purposes. 
     The locking pin is advantageously connected to the carrying arm by means of a flexible clip, so that, in the unlocked state, the situation where the locking pin gets lost is largely ruled out. 
     In order to ensure coupling of the spindle to the guide tube in the pulling direction and in the direction of rotation, it is particularly advantageous if the guide tube, with an inner radial wall and an outer radial wall, has, in the longitudinal direction, a blind hole which is provided with a polygon socket, in particular a hexagon socket, and a bore, which has a larger diameter than the spindle. In this respect, it is likewise advantageous if the spindle, at one end, has a spindle driver which connects the spindle in a rotationally fixed manner to the guide tube. 
     According to the invention, the scissor car jack has a spindle, spindle mount, crossmembers, ball bearing, a carrying head and a foot, wherein it is possible to displace and lock the two-part carrying arms of the scissor car jack, these carrying arms being rotatable in the foot and in the carrying head and being connected together by a pin on each side, wherein the spindle, which is provided with the spindle driver, can be displaced axially and, at the same time, is displaced automatically in the guide tube during the collapsing and extending operations. Since it is possible to collapse the spindle and the upper and lower carrying arms, the scissor car jack, in the delivery state, has a significantly smaller length and is thus easy to accommodate in the trunk of a passenger vehicle. 
     Advantageous embodiments of the invention are described in the dependent claims. 
    
    
     
       An exemplary embodiment of the invention is described in more detail hereinbelow and is illustrated in the drawings, in which: 
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  shows a perspective view of a scissor car jack, 
         FIG. 2  shows a side view, 
         FIG. 3  shows a front view, 
         FIG. 4  shows a plan view, 
         FIG. 5  shows a section A-A, 
         FIG. 6  shows a detail T of the spindle end, 
         FIG. 7  shows a partial section of the bearing-side crossmember, 
         FIG. 8  shows a section B-B through the handwheel, 
         FIG. 9  shows a section C-C through the spindle driver, 
         FIG. 10  shows a detail U of the guide tube, 
         FIG. 11  shows a view R as seen vertically on to the upper carrying-arm assembly, 
         FIG. 12  shows a section D-D through the locking pins, 
         FIG. 13  shows a plan view of the lower carrying-arm assembly, 
         FIG. 14  shows a section E-E through the locking pins, 
         FIG. 15  shows a section F-F through the bearing-side crossmember, 
         FIG. 16  shows a section G-G through the threaded-side crossmember, 
         FIG. 17  shows a side view in the collapsed state, 
         FIG. 18  shows a section A-A in the collapsed state, 
         FIG. 19  shows a plan view of the scissor car jack in the collapsed state, 
         FIG. 20  shows an exploded illustration of the upper carrying-arm crossmember and carrying-arm carrying head, 
         FIG. 21  shows an exploded illustration of the carrying-arm foot and lower carrying-arm crossmember, 
         FIG. 22  shows an exploded illustration of the bearing-side crossmember, 
         FIG. 23  shows a perspective view of the car jack in the collapsed state, 
         FIG. 24  shows an exploded illustration of the threaded-side crossmember, 
         FIG. 25  shows a plan view and a section of an alternative locking element, 
         FIG. 26  shows an exploded illustration of an alternative locking element, 
         FIG. 27  shows sections through an alternative guide tube, 
         FIG. 28  shows a section through an alternative locking element, and 
         FIG. 29  shows an exploded illustration of an alternative locking element. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Description Of A Telescopically Collapsible Scissor Car Jack 
     Components of a telescopically collapsible scissor car jack:
           1 . Spindle     1   a . Spindle end     2 . Spindle driver     3 . Guide tube     3   a . Guide-tube inner wall     3   b . Guide-tube outer wall     3   c . Projection     3   d . Bore     4 . Ball bearing     4   a . Handwheel-side bearing disk     4   b . Crossmember-side bearing disk     5 . Handwheel     6 . Bearing-side crossmember     7 . Threaded-side crossmember     7   a . Threaded-side crossmember end     8 . Spindle mount     8   a . Slot in the spindle mounts     9 . Annular rivet with shoulder     10 . Upper carrying-arm-part crossmember     10   a . Opening for the locking pins     10   b . Collar of the opening for the locking pins     10   c . Bore for the locking pins     10   d . Eyelets of the carrying arm     10   e . Tapered formation of the upper carrying-arm crossmember     11 . Carrying-arm-part carrying head     11   a . Guiding depression     11   b . Bore for the locking pins     11   c . Bore for the locking pins     11   d . Teeth of the carrying-arm carrying head     12 . Carrying-arm-part foot     12   a . Opening for the locking pins     12   b . Collar of the opening for the locking pins     12   c . Bore for the locking pins     12   d . Teeth of the carrying-arm foot     13 . Lower carrying-arm-part crossmember     13   a . Guiding depression     13   b . Bore for the locking pins     13   c . Eyelets of the carrying arm     13   d . Tapered formation of the lower carrying-arm crossmember     14 . Locking pin     14   a . Arm of the locking pin     15 . Foot     16 . Carrying head     17 . Foot rivet     18 . Carrying-head rivet     19 . Clip     20 . Rivet     21 . Guiding clearance     22 . Disk     23 . Magnets       

     The spindle  1  is provided with a thread and is turned to some extent at one end, so that the spindle driver  2  can be pressed or welded in. At the other end, the spindle  1  is locally pinched  1   a . The spindle driver  2  is a disk with a central bore, which corresponds to the turned part of the spindle. The circumference of the spindle driver  2  is polygonal (e.g. a hexagon) and corresponds to the polygon socket of the guide tube  3 . 
     The guide tube  3  is a thin-walled polygonal tube (e.g. a hexagonal tube) which, on one side, has a bore  3   d  with a radial wall  3   a  in the inward direction and, on the other side, has a radial wall  3   b  in the outward direction. The bore  3   d  is somewhat larger than the diameter of the spindle  1 . The spindle driver  2  is supported on the inner radial wall  3   a , it being possible for the spindle  1 , with the spindle driver  2 , to be displaced axially in the guide tube  3 . Using a polygon-socket wrench (e.g. a hexagon-socket wrench), which is positioned on the other side of the guide tube  3 , the torque is transmitted to the scissor car jack under load by means of a lever. The handwheel  5  is supported on the outer radial wall  3   b  of the guide tube  3 . The polygonal stub of the guide tube  3  fits together with the polygon socket of the handwheel  5 . This means that the torque is transmitted manually, via the handwheel  5 , to the guide tube  3  and also, via the spindle driver  2 , to the spindle  1 . The guide tube  3  is secured against axial displacement in relation to the handwheel  5  by the outer wall  3   b  and in relation to the crossmember  6  by the projection  3   c . The opposite side of the handwheel  5  serves as a support for the disk  4   b  of the ball bearing  4 . The other disk  4   a  of the ball bearing  4  is supported on the bearing-side crossmember  6 . 
     The upper carrying-arm assembly comprises an approximately U-shaped upper carrying-arm crossmember  10 , an approximately U-shaped carrying-arm carrying head  11  and two locking pins  14 , which are provided with a crosspiece arm  14   a . The upper carrying-arm crossmember  10  has, at one end, eyelets  10   d  which coincide axially with the bores of the crossmember  6  and  7 , wherein the bores  10   c  for the locking pins  14  are located laterally on limbs  10   f . At the top, there is a T-shaped opening  10   a  with a collar  10   b  for the arm crosspieces  14   a  of the locking pins  14 . 
     The upper carrying-arm crossmember  10  has a tapered formation  10   e  in the central region. The carrying-arm carrying head  11  fits, by way of the lower end, into the upper carrying-arm crossmember  10 . Located at the upper end of the limbs are the eyelets, which are provided with teeth  11   d  and, in the center, have the bores for the carrying-head rivets  18 . Located laterally on the limb of the carrying-arm carrying head  11  are shallow guiding depressions  11   a , which are of a width which is approximately equal to the diameter of the locking pins  14 . In addition, in each limb, there is a bore lib for the locking pins in the extended state and a bore  11   c  for the locking pins in the collapsed state. These bores lib and  11   c  of the carrying-arm carrying head  11  coincide axially with the bores  10   c  of the upper carrying-arm crossmember  10 . 
     The arm crosspieces  14   a  of the locking pins  14  are angled into the T-shaped opening  10   a  of the upper carrying-arm crossmember  10 , so that the locking pins  14  can be displaced axially and are secured against sliding away. As soon as the locking pins  14  have been pushed all the way in they arrest the bores  10   c  in the upper carrying-arm crossmember  10  and the bores lib in the carrying-arm carrying head  11  and thus allow forces to flow between the two carrying-arm parts  10  and  11 . The locking pins  14  can also be rotated in the T-shaped opening  10   a , so that it is possible to lock the upper carrying-arm crossmember  10  and the carrying-arm carrying head  11  during the operating cycles. Locking pins  14  which have been displaced axially outward no longer arrest the bores  11   b  of the carrying-arm carrying head  11 , and it is possible to collapse the two carrying-arm parts  10  and  11 . The two bores of the upper carrying-arm crossmember then fit axially onto the bores  11   c , so that it is possible to lock the two carrying arms  10  and  11  in the collapsed state. For this purpose, the locking pins  14  have to be forced together and thus pushed axially inward. They are then rotated in the T-shaped opening  10   a  (section D-D). 
     The lower carrying-arm assembly comprises an approximately U-shaped carrying-arm foot  12 , an approximately U-shaped lower carrying-arm crossmember  13  and two locking pins  14 , which are provided with a crosspiece arm  14 . Located at the lower end of the limbs of the carrying-arm foot  12  are the eyelets, which are provided with teeth  12   d  and, in the center, have the bores for the foot rivets  17 . The bores  12   c  for the locking pins  14  are located laterally on the limbs of the carrying-arm foot  12  and, at the top, there is a T-shaped opening  12   a  with a collar  12   b  for the angled arm crosspieces  14   a  of the locking pins  14 . The lower carrying-arm-part crossmember  13  fits, by way of the lower end, into the carrying-arm foot  12 , wherein the eyelets  13   c  are located on the limbs, and these eyelets coincide axially with the bores of the crossmembers  6  and  7 . Located laterally on the limb of the lower carrying-arm-part crossmember  13  are shallow guiding depressions  13   a , which are of a width which is approximately equal to the diameter of the locking pins  14 . A respective bore  13   b  is located on the limb, on each side, for the locking pins  14  in the extended state. These bores  13   b  of the lower carrying-arm-part crossmember  13  coincide axially with the bores  12   c  of the carrying-arm-part foot  12 . The crosspiece arms  14   a  of the locking pins  14  are angled into the T-shaped depression  12   a  of the carrying-arm-part foot  12 , so that the locking pins  14  can be displaced axially and are secured against sliding away. As soon as the locking pins  14  have been pushed all the way in, they arrest the bores  13   b  and  12   c  in the lower carrying-arm crossmember  13  and carrying-arm foot  12  and thus allow forces to flow between the two carrying-arm parts  12  and  13 . The locking pins  14  can also be rotated in the T-shaped opening  12   a , so that it is possible to lock the lower carrying-arm crossmember  13  and the carrying-arm foot  12  during the operating cycles. Locking pins  14  which have been displaced axially outward no longer arrest the bores  13   b  of the lower carrying-arm crossmember  13 , and it is possible to collapse the two carrying-arm parts  12  and  13 . The lower carrying-arm crossmember  13  has a tapered formation  13   d  in the central region. This tapered formation  13   s  means that the guiding depressions  13   a  in the lower carrying-arm crossmember  13  are incomplete. This means that, during the displacement of the carrying-arm parts  12  and  13 , the locking pins  14  are not guided to the full extent in the lower carrying-arm crossmember  13 . In order to prevent the carrying-arm parts  12  and  13  from falling out, the limbs of the carrying-arm-part foot  12  are angled inward approximately at right angles  12   e , and this ensures full guidance for the carrying-arm-part foot  12  and lower carrying-arm crossmember  13  during the displacement (see section E-E). In the collapsed state, the car jack is already locked by the locking pins  14  in the upper carrying-arm assembly. 
     The bearing-side crossmember  6  is U-shaped, with a bore in the center and two bores on the limbs. Once the upper carrying-arm assembly and the lower carrying-arm assembly has been positioned along the axis of the bores of the bearing-side crossmember  6 , the annular rivets  9  are pushed in and pressed against the eyelets  10   d  and  13   c  of the carrying arms  10  and  13  (see section F-F). The guide-tube assembly is then pushed into the central bore of the bearing-side crossmember  6  and locally deformed to a slight extent  3   c , using a pressing tool, so that it cannot slide (see  FIG. 10 ). This means that the guide tube  3  can be rotated in the bearing-side crossmember  6  and is secured axially against sliding. The upper carrying-arm assembly and the lower carrying-arm assembly can be rotated about the axis of the bearing-side crossmember  6  and are secured axially against sliding. 
     The threaded-side crossmember  7  is of U-shaped configuration, with a bore in the center and two bores on the limbs. Once the upper carrying-arm assembly and the lower carrying-arm assembly have been positioned along the axis of the bores of the threaded-side crossmember  7 , the annular rivets  9  are pushed in and pressed against the eyelets  10   d  and  13   c  of the carrying arms  10  and  13  (see section G-G). The spindle mount  8 , which has a respective slot  8   a  for the annular rivet  9  on each side, is then pushed in and the threaded-side crossmember ends  7   a  are angled approximately at right angles, so that the spindle mount is secured in the axial and radial directions. The upper carrying-arm assembly and the lower carrying-arm assembly can thus be rotated about the axis of the threaded-side crossmember and are secured axially against sliding. 
     The bearing-side crossmember  6  with the upper carrying-arm assembly and the lower carrying-arm assembly and also the threaded-side crossmember  7  with the upper carrying-arm assembly and the lower carrying-arm assembly are connected in a rotatable manner to the foot  15  at the bottom and to the carrying head  16  at the top by foot rivets  17  and carrying-head rivets  18 . 
     With the scissor car jack at a minimal height, the spindle  1  is pushed, by way of the spindle driver  2 , through the guide tube  3  in a pushing direction P′ ( FIG. 5 ) and by rotation of the guide tube  3 , via the spindle driver  2 , is screwed into the spindle mount  8  until the spindle driver  2  rests against the inner radial wall  3   a  of the guide tube  3 . A pressing tool is then used to deform the spindle end  1   a  outside the spindle mount so that it cannot be unscrewed. 
     The ready assembled car jack is raised and lowered by virtue of the spindle  1  being rotated by means of a crank, in particular a polygon-socket wrench, which fits into the end of the guide tube  3 , or by means of the handwheel  5 . If the car jack is placed under the load, the force on the carrying head  16  is transmitted to the foot  15  via the eyelets  10   d  and  13   c  of the carrying arms  10  and  13 . The other force component acts axially on the spindle mount  8  via the guide tube  3 , the spindle driver  2  and the spindle  1  in a pulling direction P″, opposing the pushing direction P′ ( FIG. 5 ) of the car jack. By virtue of the guide tube  3  being rotated via the spindle driver  2 , and thus also the spindle  1  in the spindle mount  8 , the two crossmembers  6  and  7  with the upper carrying-arm assembly and the lower carrying-arm assembly are joined together and the car jack raises the load. 
     In order to make it possible for the car jack to have a small length in the packed state, this being the actual object of the invention, the telescopically collapsible scissor car jack can be collapsed. 
     The lowest height of the car jack is set by virtue of the guide tube  3  being rotated by means of the handwheel  5  or of a torque wrench with a hexagon socket. All the locking pins  14  are then pulled outward, as a result of which it is possible to collapse the entire upper carrying-arm assembly and the entire lower carrying-arm assembly. At the same time, the spindle  1 , with the spindle driver  2 , is automatically collapsed by the same distance and, at the same time, reaches the end of the guide tube  3 . The locking pins  14  in the upper carrying-arm assembly are then forced together and rotated in the T-shaped opening  10   a , in order to lock the car jack in the packed state. This makes it possible to achieve a substantially smaller length for the telescopically collapsible scissor car jack in the packed state. 
     In order to render the scissor car jack operational again, the locking pins  14  have to be drawn out and the upper carrying-arm assembly and the lower carrying-arm assembly have to be extended. At the same time, the spindle  1  is also automatically pulled in the guide tube  3  by way of the spindle driver  2  and positioned against the inner radial wall  3   a  of the guide tube  3 . The locking pins  14  are forced together again in the T-shaped opening  10   a  and  13   a , and the locking pins  14  are then rotated and the scissor car jack is thus locked. The telescopically collapsible scissor car jack is then ready for operation again. 
     An alternative embodiment of the locking elements can be found in  FIGS. 25 and 26 . The locking pins  14  are riveted to a clip  19  to form a subassembly, which is then riveted together with the two carrying arms  10 ,  13  and  11 ,  12 . The assembly can thus advantageously replace that between the locking pins  14  and crosspiece arms  14   a . The carrying arms  10 ,  13  and  11 ,  12  are guided, during displacement, by a rivet  20  in the center of the clip  19 , as a result of which the lateral depressions  11   a ,  13   a  are dispensed with. It is likewise the case that the collars  10   b ,  12   b  on the carrying arms  10 ,  12  are no longer necessary. The carrying-arm carrying head  11  and lower carrying-arm eyelet  13  are provided with guiding clearances  21 . The lower carrying-arm eyelet  13  is provided with two holes in the region of the eyelet, so that it is also possible to arrest the locking pins  14  at the bottom in the collapsed state. Rather than the upper carrying-arm eyelet  10  and lower carrying-arm eyelet  13  being conical, they now have parallel sides. It is thus possible to arrest the locking pins  14  in the collapsed state. 
     A further alternative embodiment of the locking elements can be found in  FIGS. 28 and 29 . In this alternative embodiment, the clip  19   a ,  19   b  is in two pieces. Furthermore, the clips  19   a ,  19   b  are rigid, so that the locking pins  14  are guided in a translatory manner during locking and unlocking. The locking pins  14  additionally have magnets  23   a ,  23   b , which are attracted magnetically by the carrying arms  12 ,  11 , so that the situation where the carrying arms  12 ,  11 ,  10 ,  13  are unlocked accidentally, and the locking pins  14  get lost, is largely ruled out. 
     An alternative embodiment of the guide tube can be found in  FIG. 27 . The guide tube  3  is polygonal in the region of the inner wall  3   a  and round in the region of the bearing-side crossmember  6 . The guide tube  3  has a somewhat smaller diameter in the region of the bearing-side crossmember  6 , so that the bearing-side crossmember  6  can be supported and the pinched formation  3   c  is dispensed with. The outer wall  3   b  is dispensed with and replaced by a disk  22 , which is polygonal around the circumference and has a round bore on the inside. It is welded onto the guide tube  3  once the bearing-side crossmember  6 , the collar sleeves and the ball bearing  4  has been fitted. The annular rivets are replaced by the collar sleeves, since there is no need for any deformation of the sleeve once the guide tube  3  has been fitted in the bearing-side crossmember  6 . The collar sleeves are thus blocked, and only minimal axial movement in relation to the guide tube  3  is then possible, as a result of which the guide tube  3  can rotate without obstruction. The spindle  1  is inserted into the guide tube  3  by way of the spindle driver  2 , screwed into the spindle mount  8 , in particular a plastics-material nut, and is then pinched to some extent  1   a  at the end. The handwheel  5 , which is polygonal around the circumference, in order to allow torque transmission, is fitted onto the disk and then pinched to some extent. As an alternative, it is also conceivable for the plastics-material nut  8  and the collar sleeves  9  to be fixed by a locking plate. The handwheel  5 , on the other side, has a hexagonal formation for the wheel wrench, which can be used to raise the car jack by virtue of the handwheel  5  being rotated. 
     The invention is not restricted to the exemplary embodiments illustrated. Combining the car-jack components which have been illustrated, described or are possible with other components is always possible within the context of the claims and the rest of the disclosure.