EP1940722B1 - Lifting ram for lifting platforms - Google Patents

Description

The present invention relates to a lifting ram. Such Hubstempel be used in lifting devices such as lifts to lift vehicles to perform maintenance and repair work at different heights and working positions.

The subject underfloor lifts have at least one lifting ram, which slides vertically through a guide and on which a load bearing is attached. This load absorption engages under the vehicle. Such underfloor lifts are installed in a workshop floor.

From the prior art such Hubstempel are known. These lifting dies have a turned and ground surface, i. a precisely determined outer diameter and a high surface quality. It is known, for example, galvanically finish the surface to protect against corrosion. This manufacturing process is complex and expensive, but has the advantage that an exact guidance and storage of the Hubstempels is possible and by this way the guide length can be kept short.

From the prior art it is also known to form underfloor lifts with reversing cylinders. Such an arrangement is shown for example in German Utility Model G 90 03 685.9. The lifting punch shown there has a precisely tolerated outer diameter with a high surface quality and an electrochemical corrosion protection on. However, the present invention is not limited to lifting platforms with reversing cylinders.

In addition to an outer tube, the known from the prior art lifting rams on an inner tube, which in turn serves to receive a piston member. This outer tube and the inner tube are connected to each other in the prior art via welded connections. These welded connections are arranged, for example, at the top and at the bottom of the Hubstempels. These welds make the production of the Hubstempels consuming.

Hub stamps are stored in a stable guide in which they move up and down. In this guide sealing elements are arranged, which seal the outer diameter of the Hubstempels. However, the sealing elements do not serve to seal the hydraulic medium of the drive hydraulics, but to keep in the leadership located lubricant in the lubricating space of the guide and prevent surface water, as obtained for example when wet cleaning the workshop floor, not in the lubricating space Leadership can penetrate.

The present invention is therefore based on the object to provide a lifting ram available, which can be created in a simpler way. This Hubstempel should have a well-defined outer diameter with a high surface quality and a satisfactory corrosion protection.

This object is achieved by the subject matter of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims. It is to be understood, however, that not all the objects of the invention will necessarily be attained by the subject matters of all claims.

The lifting post according to the invention for lifting platforms, in particular for underfloor lifting platforms, has an inner tubular body, and an outer at least partially tubular body which at least partially surrounds the inner tubular body. In this case, the outer tubular body and the inner tubular body are connected by means of connecting elements at least non-positively and preferably cohesively with each other. According to the invention, the entire lifting ram is an extruded one Element, and at the upper end of the Hubstempels a cover member is arranged, which covers the Hubstempel substantially gas-tight.

A tubular body is understood to mean a body in the interior of which there is a substantially continuous cavity. Both the inner tubular body and the outer tubular body may have any cross-sections, such as circular cross-sections, polygonal cross-sections, elliptical cross-sections, combinations thereof, and the like.

Preferably, the cross section of the outer tubular body and the cross section of the inner tubular body are adapted to each other, i. for example, both circular cross-sections. However, it would also be possible to choose different cross sections, for example a polygonal cross section for the outer tubular body and a circular cross section for the inner tubular body.

Preferably, the outer tubular body substantially completely surrounds the inner tubular body.

In a further preferred embodiment, the outer and the inner tubular body are integrally formed.

By forming the Hubstempels as extruded element, the production of the same can be simplified. Also, a lifting device having such a lifting ram, are made much easier and ideally consists of only two components, namely the lifting ram and a lid arranged opposite this. In addition, the extrusion process creates a strong bond between the outer tubular body and the inner tubular body, so that the entire body has high flexural strength and can be manufactured with low material and manufacturing effort. Another advantage of extrusion is that the surface of the outer tubular body is made with a high quality can be. The same applies to the inner surface of the inner tubular body.

In a further preferred embodiment, a thread is arranged in at least one end portion of the Hubstempels. By means of this thread or a threaded bore can be attached to the end sides of the Hubstempels and in particular on the upper side load receptacles. On the underside of the Hubstempels components can be screwed, which serve as anti-rotation and / or for lowering protection. Also fasteners can be screwed, which are used in multi-level lifts to ensure synchronization. In a further embodiment, a further lifting device for a freewheel mechanism can be arranged via corresponding threaded bores.

In a further preferred embodiment, the inner tubular body is suitable for receiving a piston element and in particular a hydraulic cylinder. With this hydraulic cylinder, the lifting ram can be moved in the longitudinal direction.

According to the invention, a cover element is arranged at the upper end of the Hubstempels Hubstempels, which covers the Hubstempel substantially gas-tight. In this way, the inner tubular body is liquid-tight and tightly closed. Preferably, a closable opening is arranged in the cover. This closable opening serves to vent the inner tubular body or the hydraulic system.

In a further preferred embodiment, the inner tubular body has at its outer periphery in a lower region at least one substantially circumferential groove and preferably a plurality of circumferential grooves. These grooves are preferably formed completely encircling and can be used as grooves for guiding and sealing elements.

Preferably, a lateral opening in the inner tube is provided above the grooves. This opening serves as a hydraulic pressure connection in order to hydraulically raise and lower the lifting ram. About this opening, a medium is supplied to the inner tube. In a further preferred embodiment, the wall thickness of the inner tubular body is maintained in a thickness such that on the inside of the inner tubular body Body the above-mentioned circumferential grooves for the guide and sealing elements can be attached.

In a further preferred embodiment, the outer surface of the Hubstempels is treated electrochemically, for example, anodized or hard anodized or provided with a suitable coating. In this way, the corrosion resistance and the wear resistance of the surface are increased. Another possibility would be to firmly coat the outer surface with a PTFE-containing plastic material.

In a further preferred embodiment, at least one connecting element has a cavity extending in the longitudinal direction of the lifting ram. Also, this cavity can be produced in a simple manner by the extrusion process. In a further embodiment, all connecting elements have such cavities or, in another embodiment, two opposing connecting elements. Particularly preferably, four connecting elements are provided, which are distributed substantially uniformly in the circumferential direction of the tubular body.

Preferably, at least one cavity has a substantially circular profile. Through this profile, these cavities are particularly suitable as core holes for the above-mentioned fastening threads.

Preferably, the connecting elements are web-like and extend in a particularly preferred embodiment substantially radially from the inside to the outside.

In a further preferred embodiment, cavities are formed between the connecting elements. These cavities are arranged substantially uniformly in the circumferential direction, and more preferably between the inner tubular body and the outer tubular body. This spacing can also be produced in a particularly simple manner by means of an extrusion process. This spacing results in a total skeleton, which has a high bending or torsional strength.

In a further preferred embodiment, the outer tubular body has a smaller length than the inner tubular body. This close the outer tubular Body and the inner tubular body at the upper end of the Hubstempels substantially at the same height from each other. However, the outer tubular body is preferably shortened with respect to the inner tubular body, and more preferably substantially shortened to the level of the above-mentioned hydraulic port. In this way, access to the hydraulic connection is achieved in a particularly advantageous manner.

In a further preferred embodiment, the lifting ram has an outer cross section which is selected from a group of cross sections, which contains circular cross sections, elliptical cross sections, polygonal cross sections, in particular rectangular cross sections, combinations thereof and the like. As mentioned above, both the outer tubular body and the inner tubular body may have said cross-sections.

The present invention is further directed to a lifting device and a lifting ram according to at least one of the preceding claims. In this case, the lifting ram is at least partially arranged in a guide device. This guide device particularly preferably surrounds the lifting ram.

In a further preferred embodiment, a hydraulic cylinder is arranged in the inner tubular body. Particularly preferred sealing elements are arranged in the above-mentioned circumferential grooves of the inner tubular body. Furthermore, guide elements can be arranged in the circumferential grooves. Finally, it is also possible to provide in some grooves sealing elements and other grooves guide elements.

The present invention is further directed to a lift with at least one lifting device of the type described above. However, it is also possible to provide a plurality of such lifting devices, for example, two Haupthubvorrichtungen and two parallel to these arranged Freilaufhubvorrichtungen. Preferably, a load-receiving device is arranged on at least one lifting device and particularly preferably firmly connected to this lifting device.

The present invention is further directed to a method for manufacturing a lifting ram for lifting platforms according to claim 1.

Preferably, the lifting ram is made of a metal and particularly preferably made of aluminum.

Fig. 1

eine schematische Draufsicht auf einen erfindungsgemäßen Hubstempel und

Fig. 2

eine Seitenansicht des Hubstempels aus Figur 1.

Further advantageous embodiments will become apparent from the accompanying drawings. Hereby show:

Fig. 1

a schematic plan view of a lifting piston according to the invention and

Fig. 2

a side view of the Hubstempels FIG. 1 ,

FIG. 1 shows a schematic, not to scale true top view of a lifting piston according to the invention. This lifting ram 1 has an inner tubular body 4 and an outer tubular body 3. Between this inner tubular body 4 and the outer tubular body 3 are in the in FIG. 1 embodiment shown 4 connecting elements 5a, 5b arranged.

As in FIG. 1 indicated, these connecting elements may extend both substantially rectilinearly outwardly (5a), as well as a circular segment-shaped outer profile (5b). In further embodiments, the connecting elements 5a, 5b are preferably formed either uniformly with a substantially rectilinear profile (FIG. 5a) or else uniformly with an outer circumference (5b) which is substantially circular-segment-shaped. Also, other geometric shapes for the connecting elements 5a, 5b are conceivable.

The connecting elements 5a, 5b are produced together with the inner tubular body 4 and the outer tubular body 3 by extrusion molding.

At the in FIG. 1 shown embodiment, four such connecting elements 5a, 5b are present, which are distributed substantially uniformly in the circumferential direction. However, it would also be possible here to provide a different number, for example 3, 5 or more connecting elements 5a, 5b.

In the individual connecting elements 5a, 5b cavities 6 are present, which extend substantially completely in the longitudinal direction of the Hubstempels. The longitudinal direction runs essentially perpendicular to the plane of the figure. These cavities 6 can also be produced in the same extrusion process in which the complete extruded profile is produced.

Preferably, threads 9 are arranged in the cavities 6 in the upper end surface 7 and the lower end surface 8 of the Hubstempels. These threads 9 serve to screw on the top of the Hubstempels other elements such as load-holding or the like. At the lower end surface 8, as mentioned above, anti-rotation or other components can be screwed.

Preferably, the respective fastening threads 9 are located at the top and at the bottom of the Hubstempels on the same pitch circle diameter D, that is, the individual cavities are each equidistant from the center M of the Hubstempels. The reference numeral 13 refers to a cavity disposed inside the inner tubular body 4. In the embodiment shown here, the cavity 13 has a substantially circular profile. Within this cavity extends a (not shown) hydraulic cylinder, with the help of the lifting ram can be raised or lowered.

The reference numeral 11 refers to cavities which also arise by extrusion between the inner tubular body 4 and the outer tubular body 3. In the embodiment shown here, a total of four such cavities 11 arise.

The reference numeral 20 refers to an outer surface of the Hubstempels. This outer surface is electrolytically oxidized in a preferred embodiment to improve the surface finish.

FIG. 2 shows a side view of the Hubstempels FIG. 1 along the line AA of Figure 1. It can be seen that the inner tubular body 4 has an upper portion 4b and a lower portion 4c. The upper portion 4b has the same length L, like the outer tubular body 3, which completely surrounds the inner tubular body 4 in this embodiment. The upper tubular portion 4b is adjoined by the lower portion 4c. In this lower portion, a radially extending opening 18 is provided. This opening 18 serves as a hydraulic connection to supply the interior 13 with a hydraulic medium. In the region of the opening 18, the outer tubular body is also removed, so that a screw with a hose or pipe (not shown) can be introduced. More specifically, at the in FIG. 2 shown embodiments, both the outer tube and the connecting elements 5 to over the opening 18 removed.

In the lower portion 4c of the inner tubular body 4, a plurality of circumferential grooves 17, 19 are provided on the inner circumference 4a thereof. These grooves are introduced in the form of turns. In the grooves 17, 19 (not shown) sealing and guide rings can be installed.

At the upper end of Hubstempels a cover 12 is arranged. This cover is connected to the inner tubular body 4 and preferably welded. Furthermore, the cover is recessed against the upper surface 7 of the Hubstempels, so screwing other elements is not hindered by the cover 12. In the lid, a vent hole 16 is arranged, which has a threaded bore 16a and can be closed with a (not shown) closing element. The vent hole 16 serves to vent the hydraulic system.

LIST OF REFERENCE NUMBERS

1

lifting ram

3

outer tubular body

4

inner tubular body

4a

Inner wall of the inner tubular body 4

4b

upper portion of the inner tubular body

4c

lower portion of the inner tubular body

5a, 5b

fasteners

6

cavities

7

upper end surface

8th

lower end surface

9

thread

11

cavity

12

cover

13

Cavity between the connecting elements 5a, 5b

16

vent hole

16a

Thread of the vent hole

17, 19

circumferential grooves

18

opening

20

outer surface

M

Focus

D

Pitch diameter

Claims (14)

1. Lifting ram for lifting platforms, in particular for underfloor lifting platforms, comprising an inner tubular body (4) and an outer body (3) which is at least partially tubular, which at least partially surrounds the inner tubular body (4), wherein the outer tubular body (3) and the inner tubular body (4) are connected to one another at least in a force-fitting manner via connecting elements (5a, 5b), characterised in that the entire lifting ram is an element which is extruded and wherein a covering element (12) is arranged at the upper end of the lifting ram, which covering element covers the lifting ram in an essentially gastight manner.
2. Lifting ram according to claim 1, characterised in that the outer tubular body (3) and the inner tubular body (4) are formed as one piece.
3. Lifting ram according to claim 6, characterised in that a closable opening (16) is arranged in the covering element (12).
4. Lifting ram according to at least one of the claims 1 - 3, characterised in that a thread (9) is arranged in at least one end section (7, 8) of the lifting ram.
5. Lifting ram according to at least one of the preceding claims, characterised in that the inner tubular body (4) is suitable for accommodating a piston element and in particular a hydraulic cylinder.
6. Lifting ram according to one of the claims 1 - 5, characterised in that at least one connecting element (5a, 5b) has a cavity (6) extending in the longitudinal direction L of the lifting ram.
7. Lifting ram according to claim 6, characterised in that the connecting elements (5a, 5b) are formed in the manner of webs.
8. Lifting ram according to at least one of the preceding claims, characterised in that the outer tubular body (3) has a smaller length than the inner tubular body (4).
9. Lifting ram according to at least one of the preceding claims, characterised in that the lifting ram has an outer cross section selected from a group of cross sections comprising circular cross sections, elliptical cross sections, polygonal cross sections, in particular rectangular cross sections, combinations thereof and the like.
10. Lifting device comprising a lifting ram according to at least one of the preceding claims.
11. Lifting device according to claim 10, characterised in that a hydraulic cylinder is arranged in the inner tubular body (4).
12. Lifting device according to at least one of the claims 10 - 11, characterised in that sealing elements are arranged in the circumferential grooves (17) of the inner tubular body (4).
13. Lifting platform comprising at least one lifting device according to at least one of the claims 10 - 11.
14. Method for producing a lifting ram, according to at least one of the claims 1 9, characterised in that the whole lifting ram is produced by an extrusion process.

Images