DE2844436A1 - Heavy duty load lifting equipment - has telescopic sleeves with screw thread and ball drive, inside motor driven sleeve - Google Patents

Abstract

The heavy duty load lifting device has a stationary vertical tube enclosing concentric telescopic lifting sleeves inside a driving tube. All the mating surfaces of the moving tubes incorporate helical grooves which retain ball bearings between them to give a lifting action when the driving tube is rotated. Mounted on the outside is a drive motor and reduction gear with a bevel pinion on its output shaft, meshing with teeth on the top of the driving tube, to rotate it. The inner -most tube carries a pad on top, to lift the load. The whole is mounted on a flanged base with balls inside for travelling. These balls are retracted under load so that the weight is taken on the inner ring of the base.

Description

Jack

The invention aims to create a jack for lifting and Lowering loads of various kinds, which has a compact structure, a cheap one Lifting height, can be easily moved in all directions and its drive and lifting means to the outside against dirt, damage or the like. Encapsulated are, so that it has a permanently durable operational readiness. Farther the lifting means of the jack should be able to be moved in height in a way that saves effort and is easy to move which means that the jack can be used in a variety of ways.

According to the invention, the jack is by a fixed, upright Standpipe, an axially rotatable therein and secured against displacement in the vertical direction, manually or motorized rotatable drive tube and several in the drive tube arranged, Lifting tube that can be telescopically moved together and apart via ball roller guides characterized, wherein the interior of the lifting tubes at the top with a load bearing part is provided and held against rotation by telescopic guides.

The lifting tubes that can be pulled up out of the stand and drive tube have a smooth surface on the outside and some are on the inside with a thread occupying almost their entire length as well as on the outside at the lower end Equipped with at least two threads in which circulating Balls are arranged, the tubes with the internal thread of the hub and the drive tube to move the lifting tubes cooperate in the manner of a ball screw spindle.

Under each lift tube is one from a threaded socket and inside lying balls formed safety nut arranged with the respective Lifting pipe is connected in terms of movement and its balls are also connected to the pipe thread cooperate. This safety nut is normally unloaded and only kicks in in the event of malfunctions in the stroke of a lifting tube by reducing the load records and works according to the lifting tube.

The drive tube can be topped with a circumferential toothing equip in which a hand crank or gear motor driven Pinion engages to rotate the drive tube.

The anti-rotation telescopic guide is made up of several interlocking ones Polygonal tubes formed, of which the outer one on the bottom and the inner one is attached at the top of the load-bearing part and the alternately at the top and bottom and outside or

with driver on the inside for mutual taking along of the polygonal tubes are equipped.

The load-bearing part that is exchangeably attached to the inner lifting tube can be designed in various ways, for example as a spherical support body, as a plate, as a claw or as a fork pulled down to the side.

On the upper face of the standpipe and the lifting tubes is a more circumferential, with a seal on the outer surface of the lifting tubes Final ring set.

The jack foot is a hollow body with an upstand and several in the unloaded lifting jack condition emerging from the foot on the underside and the Lifting jack movable bearing balls formed, which when the load is picked up by the Lifting jack to be pressed into the foot against its spring tension, so that the foot with its wreath is securely supported on the floor surface.

Further features emerge from the other subclaims. Of the The subject matter of the invention extends not only to the features of the individual claims, but also on their combination.

The advantages of the jack according to the invention are as follows: 1. The Lifting jack is compact because its tubular lifting means are telescopic are collapsible and can be retracted into an outside standpipe, so that he has a has a small height and a small cross-section, which makes it easy to get closer to a wide variety of loads and thus a large area of application.

2. The lifting tubes are effortless and easy to move thanks to ball roller guides height-adjustable - this makes manual and motorized drive possible in a simple manner.

3. A safety nut is assigned to each lifting tube, which also works with a ball roller guide and in the event of malfunctions in the associated lifting tube becomes effective, so that a sudden lowering of the lifted load is eliminated.

4. The inner lifting tube holding the load-bearing part in an exchangeable manner is easier thanks to telescopic, mutually displaceable rectangular tubes Way secured against axial rotation, which is advantageously inside Extend the lifting tube without interference and work.

5. The load-bearing part can be designed in various ways and enables axial and also lateral load application.

6. The jack is light thanks to balls placed in its base movable in all directions, hlil movable, so that it can easily be attached to any load can be brought up.

7. The drive and lifting means of the jack are outwards Against dirt, damage or the like. Arranged closed and run in a lubricant bath, which guarantees a long-term, long-term operational readiness is.

8. The jack is a mechanical, versatile lifting device designed with favorable lifting heights.

9. The entire lifting jack is designed to be accident-proof because its height-adjustable means are smooth on the outside and therefore no crushing points, do not create any protruding points of being carried along or injuries for the operator.

10. Since the jack according to the invention has a mechanical lifting device forms, which can be moved without pressure medium by means of sliding ball guides Lifting means works, this jack has no conventional hydraulic device (Hydraulic pump, hydraulic lines or the like, which on the one hand are susceptible to operation (Bursting of the hydraulic lines) and thus prone to malfunctions and the risk of accidents and on the other hand, due to the lead to contamination or the like.

left The previous motorized and pressure-operated lifting jacks continue to show unfavorable outer contours, which on the one hand lead to unfavorable handling lead and on the other hand are spatially inexpedient and furthermore accident risks form what the lifting jack according to the invention by its clear external shape in simple and safely avoids.

An exemplary embodiment according to FIG the invention explained in more detail.

Thereby: FIG. 1 a side view of a lifting jack; Fig. 2 a Top view of the jack; 3 shows a vertical longitudinal section through the eebock in the collapsed, unloaded condition; Fi. 4 shows a vertical longitudinal section through part of a lifting tube of the jack with ball roller guide; Fig. 5 shows a vertical longitudinal section through a partial area of the jack foot with the ball in the unloaded state; 6 shows a vertical longitudinal section through the jack foot according to Fig. 5 in the loaded state.

The lifting jack according to the invention for lifting and lowering loads of various kinds Art has a fixed, with the longitudinal direction in the vertical direction Standpipe 1 on, in which an axially rotatable and in the vertical direction Is arranged against displacement secured drive tube 2, which manually or is rotated axially by the motor.

In this drive tube 2 are several ball roller guides 6, 7, 8 telescopically collapsible and extendable lifting tubes 3, 4, 5 arranged from which the inner lifting tube 5 provided with a load bearing part 9 and through Telescopic guides 10 is held against rotation. The vertical standpipe 1 is supported is on a movable jack foot 11 with its lower end and carries a drive device 12 at the upper end.

The interlocking tubes 1 to 5 have a circular cross-section and are cylindrical in the longitudinal direction.

The drive tube 2 is through in its upper and lower end areas each one roller bearing secured against vertical movement relative to the standpipe 1 and easily rotatable with respect to the standpipe 1 by these two roller bearings intended. Each roller bearing is in this case of a circumferential ring channel 14 with a circular Cross-section, that consists of a groove that is semicircular in cross section on the inside of the standpipe 1 and a groove that is semicircular in cross section is composed on the outside of the drive tube 2 and from a plurality formed by balls 13 lying in this annular channel 14. The balls 13 are each through a radial bore in the standpipe 1 that can be closed by means of a screw 15 introduced into the annular channel 14.

At the upper front end, which is below the upper front end of the standpipe 1 is located, the drive tube 2 is a circumferential toothing 16 worked, in which encloses a drive pinion 17 for the drive tube rotation.

This drive pinion 17 forms an angular drive with the toothing 16 and sits on a drive shaft 18.

This drive shaft 18 forms part of the drive device 12 and engages in a transmission 19, which is driven by a motor 20, such as an electric motor, Internal combustion engine, pressure medium engine or the like. Is driven. Furthermore there is the possibility of equipping the drive shaft 18 with a slip-on attachment a hand crank can be attached, so that the drive tube 2 by hand the gear 16, 17 can be rotated.

The drive device 12 formed from motor 20 and gear 19 is flanged on the outside at the top of the jacket of the standpipe 1, the Motor 20 below the Gear 19 is and thus this drive device 12 is arranged on the side of the standpipe 1 and thereby a cheap, little after has external space arrangement.

The moving upward out of the drive and standpipe 2.1 Lifting tubes 3 to 5 have a smooth outer surface and are on their inner Outer surface with a thread extending over almost the entire length of the pipe 22, 23, the inner lifting tube 5 being designed without a thread. The drive tube 2 also carries almost the entire length of the pipe on its inner jacket surface male thread 21.

In the lower end area, the lifting tubes 3 to 5 have on their outer ones Jacket surface in each case at least two threads 24, 25, 26. These outer Threads 24 to 26 do not follow when the lifting tubes 3 to 5 are moved out outside before, but remain in the nested pipe area, so that from the outside no contamination or damage to the threads can occur and the smooth Execution of the lifting tubes 3 to 5 is not impaired.

The Cewinaegun-e 24 to 26 of each lifting tube 3 to 5 are with one Plenty of balls 27 filled in, the parts in the threads 24 to 26 and for other part engage in the thread 21, 22, 23 of the adjacent tubes 2, 3, 4 and with the threads 24, 25, 26/21, 22, 23 form the ball roller guides 6, 7, 8.

The upper and lower end portions of those threads 24, 25, 26 of the pipes 3, 4 5 is connected by a vertical channel 28, so that the balls 27 each Tube 3, 4, 5 in the manner of a ball screw i circuit through the pipe thread 24, 25, 26 move. which will be explained in more detail later.

The vertical channel 28 is through an oblique downward or downward The transition channel 29 established above is connected to the end of the thread 24, 25, 26. From the lower end in each tube 3, 4, 5 one od by a screw.

Like. Lockable insertion hole 30 introduced, which up to the thread 24, 25, 26 and an introduction of the balls 27 into the interacting thread 24, 21/25, 22/26, 23 enabled.

A so-called safety nut is assigned to each lifting tube 3, 4, 5, which in the event of malfunctions in the ball roller guide 6, 7, 8 of a pipe 3, 4, 5, the load-bearing Takes over the function so that there is no sudden lowering of the load, but the corresponding lifting tube 3, 4, 5 is ready for use by means of its safety nut remain.

For this purpose, each is at a certain distance under the lower face Hubrohres 3, 4, 5 a square or rectangular in cross section, in thickness the pipe wall thickness corresponding ring 31 is arranged, which is through in the underside Blind bores 32 of the ring 31 engaging pins 33 with the respective Lifting tube 3, 4, 5 is connected in terms of movement.

Each locking ring 31 has at least one filled with balls 34 Thread 35 and these balls 34 interact with the thread 21, 22, 23 of the tubes 2, 3, 4 together. Should faults in a ball roller guide 6, 7, 8, for example due to damage to the balls, the said lifting tube 3, 4 lowers, 5 around the gap between the pipe face and locking ring 31 on this from and then the ring 31 takes over the supporting function by its previously unloaded Balls 34 are loaded in the threads 35 and 21/22/23 and as a ball roller guide works. A ball circuit is also present in these securing threads 35.

On the upper face of the standpipe 1 and the two outer ones EIubrohre 3, 4 is od by screws. Like.

in each case a locking ring 36 attached, which with a circumferential poetry 37 rests against the outer surface of the adjacent tube 3, 4, 5. The closing ring 36 on the standpipe 1 engages over the drive pipe 2 and rests on the outer lifting pipe 3.

On the inner lifting tube 5, the load receiving part 9 is through at the top Screws or the like fastened detachably (exchangeable). This load bearing part 9 is For example, formed by a spherical support body, which in its basic shape corresponds at most to the outer cross-section of the lifting tube 5. There is also the possibility this load-bearing part 9 from a claw, from a laterally down to the standpipe 1 Lift fork, a plate or the like. To form.

The anti-rotation telescopic guide 10 is made of several square tubes 38 formed, of which the inner square tube 38 with its upper end under the Load-bearing part 9 fastened, for example by a load-bearing part 9 reaching through and in a fixed in the square tube 38 bushing 39 encasing screw 40 is and the outer ste square tube 38 is welded with its lower end to a plate 53 and with this plate 53 on the jack foot 11 by screws or the like. Is fixed.

The interlocking square tubes 38 are alternately on top and at the bottom with stops 41, for example of two opposite one another Outside or. Inner sides of the square tubes 38 welded webs are formed, equipped, on the one hand when moving the square tubes 38 this a certain Giving guidance and, on the other hand, taking along the square tubes 38 when extending serve above. By the two (inner and outer) on the load bearing part 9 and on The square tubes 38 attached to the foot 11 are twisted in the case of the Elubrohr screwing been excluded, so that thereby the inner lifting tube 5 is secured against rotation is. There is always one square tube 38 more than the number of lifting tubes 3 to 5.

The foot 11 is formed in several parts and has a standpipe 1 upright wreath 42, a base plate fastened under the standpipe 1 43, on which the outer square tube 38 is attached, a circumferential around the rim 42, outwardly protruding footplate 44 and with this footplate 44 a cavity 46 forming cover part 45.

To move the jack, this is in its foot 11 with several, for example four or six evenly distributed over the circumference of the foot 11 arranged balls 47 provided, when the lifting jack is relieved of the process the same from the bottom of the foot 11 partially step out and under load of the The lifting jack is pressed into the foot 11 be so that the jack is supported with his foot 11 (ring 42) on the standing surface and no further can be proceeded.

In the base plate 44 a Bohruno 48 is excluded for each ball 47, the bore seats of which form a funnel-shaped (conical) spherical contact surface, wove. the circumferential pand 48a in the pressed-out state of the ball 47 on the same rests as a sealing edge, so that the Fuß-Fiohlraum 46 inwardly against dirt or the like is completed.

In the bore 48, a guide bush 49 is used in which a downwardly open, the ball 47 overlapping pot 50 is vertically movable. The bottom of the pot 50a presses against the ball with the interposition of balls 51 47 and around the Tccf 50 a compression spring (coil spring) 52 is arranged, which at one end from the pot rim 50b and at the other end on the cover part 45. These When the jack is unloaded, spring 52 pushes pot 50 with ball 47 downwards the foot plate 44 out until the ball 47 on the sealing edge 48a is present.

When the jack is loaded, the ball 47 with the pot 50 counteracts it the compression spring 52 is pressed into the foot 11, as far as until the ring 44 touches down on the standing surface. The ball 47 is through the small Balls 51 rotatably mounted in the foot 11 so that the jack can be moved effortlessly in all directions.

Figure 5 shows the jack in the unloaded, movable state Balls 47 and Fig. 6 protruding from the underside indicate the loaded lifting jack position again, in which the balls 47 are pressed into the foot 11 and the jack with its rim 44 is supported on the floor surface.

To lift a load, the jack is moved under the load and then by turning the pinion 17 manually or by means of a motor, the axial Rotational movement of the drive tube 2 within the non-rotatable standpipe 1. At Axial rotation of the drive tube 2 results in an unscrewing of the drive tube 2 adjacent lifting tube 3, which the other two lifting tubes 4, 5 or own Height shift takes along, i.e. the lifting tubes 4, 5 remain pushed into one another and pushed into the lifting tube 3 and only migrate upwards with the same with.

As the drive tube 2 rotates and it over the ball roller guide 6 is in frictional connection with the lifting tube 3, this lifting tube 3 screwed upwards from the drive tube 2 and also from the standpipe 1 out - so it makes a height shift.

The one, two or more thread 24 of the lifting tube 3 is with Balls 27 full and these balls 27 roll in the thread 21 of the drive tube 2 and pass through the entire pipe thread 24 at the same time.

If a ball 27 reaches the upper end of the thread 24, it falls through the channels 29, 28 back down to the lower beginning of the thread 24 and this is repeated with each ball 27, so that all balls 27 are in move in a cycle and at the same time unscrew the lifting tube 3 upwards. If this lifting tube 3 has reached its uppermost position, then a Kuel strikes 27 to the end of the thread 21 of the drive tube 2 and thereby the flub movement of the lifting tube 3 ended.

Now this lifting tube 3 rotates with the drive tube 2 and now the second lifting tube 4 is screwed out of the lifting tube 3 via the ball rolling guide 7. Has this jack tube 4 by striking a ball 27 on the upper end of the thread 22 reaches its uppermost end position is achieved by rotating the drive tube 2 with the two lifting tubes 3, 4, the third lifting tube 5 pushed out, which through the telescopic guide 10 held against rotation and only shifted in height / direction will.

With all lifting tubes 3, 4, 5 the ball roller guide 6, 7, 8 after, in that the balls 27 move in a circuit and with the associated thread 21, 22, 23 result in the displacement of the tubes 3, 4, 5. The largest extended position of the jack is by striking a ball 27 of the ball roller guide 8 on the upper thread end of the lifting tube 4 is limited.

When the lifting tubes 3, 4, 5 are exported, the telescopic tubes 38 are successively also pulled apart by first pulling the in the outer fixed tube 38 stored pipe 38 is taken upwards, then with its lower-end stop 41 strikes against the upper-end stop 41 of the tube 38 stored therein and take this with you, etc.

When the lifting tubes 3, 4, 5 are retracted, the same functional sequence takes place in reverse order by the lifting tubes 3, 4.5 one after the other through the ball roller guides 6, 7, 8 pushed in and the telescopic tubes 38 pushed together again.

The number of lifting tubes 3, 4, 5 can be chosen as desired and can two or more than three pieces. The lifting height of the jack is on the one hand on the length of each lift tubes 3, 4, 5 and the other Depending on the number of lifting tubes and according to the desired lifting height, the Fubrohre 3, 4, 5 determined in length and number.

The Louube tubes 3, 4, 5 and the telescopic guide 10 run in a lubricant bath. Through the foot 11, which is closed at the bottom, and through seals 37 on the pipe side the interior of the lebebock is closed off from the outside with the oil bath and thereby permanent, trouble-free and low-lock operation is guaranteed. The seals 37 strip the lubricant from the outer surface of the tubes 3, 4, 5 when moving the animal safely off, so that the outwardly protruding parts 3, 4, 5 are largely freed from Cl and result in 1zone spots of dirt.

The threads 21, 22, 23 and 24, 25, 26 and 35 can be with a the balls 27, 34 adapted, partially circular cross-section or with a trapezoidal or form a triangular cross-section.

The entire jack is made of metal.

L e r s e i t e

Claims (22)

P a t e n t a n 5 p r ü c h e 1. Jack for lifting and lowering Loads of various kinds with a movable stand and one that can be moved up and down Load receiving part, g e k e n n z e i c h -n e t d u r c h a stator forming, fixed, upright standpipe (1), one axially rotatable therein and in the height direction Manually or motor-driven rotatable drive tube, held in a non-shift position (2) and several in the drive tube (2) arranged via ball roller guides (6,7,8) telescopically collapsible and extendable lifting tubes (3, 4, 5), of which the inner lifting tube (5) above di? provided with a load-Aufnahrlteteil (9) and through Telescopic guides (10) is held against rotation. 2. Lifting jack according to claim 1, d a d u r c h g e k e n nz e i c h n e t that the standpipe (1), the drive pipe (2) and the lifting pipes (3, 4, 5) are circular Have cross-section and cylindrical in the longitudinal direction (height direction) are. 3. Lifting jack according to claims 1 and 2, d a d u r c h g e k e n n it is clear that all lifting tubes (3, 4, 5) have a smooth outer surface on the outside have and with the exception of the inner lifting tube (5) on the inside with almost the entire Pipe length occupying thread (22,23) as Part of the ball roller guide (7,8) are equipped. 4. Iebock according to claims 1 to 3, d a d u r c h g e k e n It is noted that the drive tube, which has a smooth dumbbell surface on the outside (2) in the upper and lower end area by a roller guide in the form of in the standpipe (1) and in the drive tube (2) excepted, semicircular in cross-section and one Ring channel (14) forming grooves and arranged therein, filling the ring channel (14) Balls a3) rotatable in the standpipe (1) and in at least one roller guide (13, 14) the axial loads is supported so as to accommodate the balls (13) by means of Screws (15) or similar closable holes in the standpipe (1) in the ring channels (14) are introduced. 5. Lifting jack according to claims 1 to 4, d a d u r c h g e k e n n z e i c h n e t that the drive tube (2) on the inside with almost the entire Tube length occupying thread (21) equipped as part of the ball roller guide (6) is. 6. Lifting jack according to claims 1 to 5, d a d u r c h g e k e n n z e i c h n e t that the lifting tubes (3, 4, 5) in the lower end region at their outer Outer surfaces equipped with an at least two-start thread (24, 25, 26) are, which with the inside thread (21, 22, 23) of the tubes (2,3,4) a Runway of the Ball roller guide (6,7,8) forms and this thread (24, 25,26) is filled with balls (27) that go into the Kohr thread (21, 22, 23) intervene to move the lifting tube in height. 7. Lifting jack according to claims 1 to 6, d a d u r c h g e k e n n z e i c h n e t that each outside thread (24, 25, 26) of the lifting tube side Ball roller guide (, 7,8) through transition channels inclined downwards or upwards (29) and a vertical channel (28) are connected at their two ends and form an annular channel in which this annular channel (24, 29, 28/25, 29, 28/26, 29, 28) filling balls (27) are movable in the circuit (Fig. 3 and 4). 8. Lifting jack according to claims 1 to 7, d a d u r c h g e k e n n z e i c h n e t that the threads (24,25,26) in the lifting tubes (3,4,5) and the threads (21,22,23) in the tubes (2,3,4) have a part-circular or trapezoidal cross-section own. 9. Lifting jack according to claims 1 to 8, d a d u r c h g e k e n n z e i c h n e t that each lifting tube (3,4,5) in its lower end face one to to the thread (24, 25, 26) extending insertion bore (30) for the balls (27), which can be closed by a screw or the like. 10. Lifting jack according to claims 1 to 9, d a d u r c h y e k e n It is not indicated that a safety nut is assigned to each lifting tube (3, 4, 5), the one arranged at a short distance below the lower pipe face, ring (31) connected to the lifting tube (3, 4, 5) by means of drivers (33) with at least a thread (35) filled with balls (34) is formed, the balls (35 interact with the thread (21,22, 23) of the adjacent tubes (2,3,4). 11. Lifting jack according to claims 1 to 10, d a d u r c h b e k e n It is noted that the upper and lower ends of each thread (21,22,23) have the balls (27) cooperating displacement limit stops for the individual Lifting tubes (3,4,5) forms. 12. Lifting jack according to claims 1 to 11, d a d u r c h g e k e n n z e i c h n e t that the upper end face of the drive tube (2) with a circumferential Toothing (26) is equipped, in which a pinion (17) of the manual or motorized Drive device (12) engages. 13. Lifting jack according to claims 1 to 12, d a d u r c h g e k e n It is noted that the drive device is located on the side of the standpipe (1) in the upper end area (12) is flanged by an electric motor (20), hydraulic motor, Internal combustion engine or the like is formed with a gear (19), the drive pinion (17) sits on a gear shaft (18) and an angular drive with the toothing (16) forms. 14. Lifting jack according to claims 1 to 12, d a -d u r c h g e k e n n z e i c h n e t that the drive pinion (17) on a plug-on approach to define a hand crank for manually driving the drive tube (2) Shaft (18) is arranged. 15. Lifting jack according to claims 1 to 14, d a d u r c h g e k e n It is indicated that on the standpipe (1) and the two outer lifting tubes (3, 4) each at the top a locking ring (36) by screws or od. Like. Is attached, the one on the outer surface of the adjacent, inner tube (3, 4, 5) holding ring seal (37). 16. Lifting jack according to claims 1 to 15, d a d u r c h g e k e n n z e i c h n e t that on the upper face of the inner lifting tube (5) a of a spherical support body, a plate, a claw, one on the side of the standpipe (1) lowered lifting fork or the like. formed load-receiving part (9) exchangeable by screws (40) is attached. 17. fIebock according to claims 1 to 16, d a -d u r c h g e k e n n z ei c h n e t that the anti-rotation telescopic guide located in the inner lifting tube (5) (10) of several mutually engaging polygonal tubes, preferably square tubes (38) is formed, of which the outer square tube (38) with its lower end fixed on the lifting jack foot (11) and the inner square tube (38) with its upper End under the load-bearing part (9) are attached and the square tubes (38) alternately at the upper and lower end inside and outside driver (41) have for the mutual displacement drive of the square tubes (38). 18. Lifting jack according to claims 1 to 17, d a -d u r c h g e k e n n z e i c h n e t that in the foot (11) designed as a hollow body there are several evenly distributed around the circumference of the foot, in the unloaded Hebeboc condition the foot (11) underneath to move the jack, kicking balls (47) mounted movable in height are which when the load is picked up by the The jack can be lowered into the foot (11). 19. Lifting jack according to claims 1 to 18, d a -d u r c h g e k e n n z e i h n e t that a foot plate (44) of the foot (11) for each ball (47) has a bore (48), the funnel-shaped bore end of which has a circumferential, with protruding ball (47) at the same sealing edge (48a) forms (Fig. 5). 20. Lifting jack according to claims 1 to 19, d a d u r c h g e k e n It is noted that in each bore (40) of the footplate (44) a guide bushing (49) is used, in which a under the action of a compression spring (52), the ball (47) overarching pot (50) which is vertically movable with its pot bottom (50a) with the interposition of several smaller balls (51) on the ball (47) acts (Fig. 5 and 6). 21. Lifting jack according to claims 1 to 20, d a d u r c h g e k e n It is noted that the pot (50) at its downwardly directed pot opening has an outwardly directed circumferential edge (50b) on which the to the pot (50) arranged compression spring (52) supports with one end, the other End on an upper cover part (45) of the foot (11) is present. 22. Lifting jack according to claims 1 to 21, d a d u r c h g e k e n It is noted that the foot (11) forms a lifting jack support surface and the standpipe (1) has upright rim (42) on which the in the basic shape circular foot plate (44) and laterally circumferential and overhead, the foot (11) a cavity (46) for the ball assembly giving cover parts (45) attached are.