DE20016624U1 - Scissor lift table - Google Patents

Description

^: ·· ^: "'Ullrich & Naumann

Industrial property rights· Intellectual Property

3463/E/003

Heidelberg, September 22, 2000/ed

Utility model application

of the Lord

concerning a

Eckhardt Penzek Talstrasse 43

66386 St. Ingbert

"Scissor lift table"

Representative office Spain

E - 03720 Benissa, Alicante

Luisenstrasse 14 D-69115 Heidelberg -telephone +49 62 21/60 43-0 _> I Fax +49 62 21/60 43-60 'e-mail: un@hd-patent.de

The invention relates to a scissor lift table with a lower frame, an upper frame forming a working plane or a table and a scissor mechanism acting between the lower frame and the upper frame, wherein the scissor mechanism comprises intersecting inner and outer scissor members which can be actuated to raise or lower the upper frame and wherein drive means are assigned to at least one pair of the intersecting scissor members.

Scissor lifts of this type have been known in practice for many years. Reference is made to DE-AS 11 75 852 and the registered documents of the German utility model 79 32 713 as examples. The drives disclosed therein, together with the actuating element that applies force to the scissor links, are state of the art and will not be discussed further below.

DE 196 49 867 A1 discloses a generic scissor lift table in which the free ends of the scissor links on one side are pivotally connected to the upper and lower frames via fixed joint axes. On the other side, the free ends of the scissor links are equipped with rollers and run in the guide rails assigned to the upper frame and the lower frame. If the scissor mechanism is erected by the gear motor provided there, the ends of the scissor links provided with fixed joint axes remain stationary on one side of the two frames. When the scissor mechanism is erected, the opposite free ends of the scissor links roll towards the middle, thus approaching the ends of the scissor links that are stationary in relation to the two frames, which results in the erection movement and thus the raising of the table level.

In practice, the scissor lift table is problematic with regard to the scissor mechanism and its drive, in that both the drive itself and the effective connection between the drive and the scissor mechanism, in particular the drive means implemented there, are on the one hand complex in terms of construction and on the other hand prone to repairs. The well-known scissor lift table lacks the robustness required, especially for heavy loads.

Based on the problems described above with a generic scissor lift table, the present invention is now based on the object of designing and developing a generic scissor lift table in such a way that, with a robust construction, safe functioning is guaranteed even with heavy loads.

The above object is achieved by the features of claim 1. According to this, a generic scissor lift table is characterized in that two curves are assigned to one scissor link and two carriages, slides or the like that can be moved along the scissor link on the curves towards and away from each other are assigned to the other scissor link as drive means.

According to the invention, it has therefore been recognized that a robust and at the same time operationally reliable design of the drive means can be realized by implementing a type of tandem drive, according to which two curves are assigned to the scissor link that previously carried the single curve. Accordingly, two carriages, slides or the like that can be moved along the scissor link on the curves towards and away from each other are assigned to the other scissor link, with the interacting curves and carriages, slides or the like forming the essential drive means of the scissor lift table. According to the invention, when the work surface or table is lifted, the load is distributed over at least two arrangements of curves and carriages, slides or the like, with the interaction between the carriage, slide or the like and the curves causing the actual lift of the scissor mechanism. Ultimately, the at least two carriages, slides or the like are to be moved along the two curves so that the work surface or table is lifted.

Advantageously, the carriages, slides or the like are positioned in such a way that when the upper frame or the working level is lowered, they rest on the curves on both sides in the edge area. To raise the upper frame, the carriages, slides or the like can be moved towards each other via a drive along the scissor link guiding the carriages, slides or the like on the curves or in engagement with the curves. To lower the upper frame,

The carriages, slides or the like can be moved away from each other within the frame, which in the simplest case is done via gravity.

It is also advantageous if the two curves are arranged on both sides of the intersection point of the scissor links, preferably at least slightly spaced from this, on the respective scissor link. Such a design provides a central center of gravity and contributes to the stable and stable design of the device.

It is also conceivable that at least one of the two curves can be changed in its position on the scissor link in order to bring about a change in the lifting characteristics. To do this, the curves could be changed in their position along the scissor link and in their angle to the scissor link. It is also conceivable to exchange the curves in order to be able to achieve a different lifting characteristic by changing the shape of the curve. Optimal adaptation to the loads to be lifted and to other conditions is possible.

It should be particularly emphasized that the curves with their predeterminable curve shape serve to influence the kinematics and dynamics of the lifting/lowering movement. The curves can be designed in such a way that the upper frame or the table is raised and/or lowered at a constant speed when the drive speed is constant. The interchangeability of the curves means that the scissor lift table has the greatest possible flexibility.

With regard to the distribution of forces during the lifting movement, it is also advantageous if the two curves with their active or running surfaces are arranged on opposite sides of the scissor link, so that the carriages, slides or the like run on opposite sides. A mutual pushing away between the two curves on the one hand and the carriages, slides or the like on the other causes the scissor mechanism to be activated and thus the table to be raised.

In the context of a particularly simple construction, it is advantageous if the carriages, slides or the like run in a rail assigned to the respective scissor link, whereby the rail can be U-shaped in cross-section. In concrete terms, the rail could be provided on the side of the scissor link, preferably on the respective inner side, whereby the carriages, slides or the like can be moved in the rail or roll in the rail. In the context of a particularly simple design, a slide could be moved within the rail.

A reduction in the forces required when starting up is achieved when a carriage rolls in the rail with the lowest possible rolling resistance. In this respect, the guide elements of the carriage that engage in the rail could be designed as rollers, preferably with ball bearings, whereby the guide elements require sufficient space within the rail.

For the scissor lift table to function properly, it is also advantageous if the carriages, slides or similar each have at least one removal roller, preferably with ball bearings, for rolling along the curve. This also reduces the forces required for opening or raising. Proper movement along the curve surface is guaranteed.

As already explained above, the movement of the carriage, sledge or the like along the curve surface serves to operate the scissor mechanism. Any drive for the carriage, sledge or the like can be implemented. In a particularly advantageous manner, the carriage, sledge or the like are moved by traction means, with very special precautions being implemented on the carriage, sledge or the like for this purpose. In concrete terms, the carriage, sledge or the like could have very special holding means and/or at least one deflection roller for a traction means, with the traction means connecting the two carriages, sledges or the like to one another from the drive side via their holding means and via the deflection rollers in such a way that when the traction means is pulled, the two carriages, sledges or the like - rolling on the curves - can be moved towards one another under the effect of a pulley.

At this point, it should be particularly emphasized that implementing the pulley effect mentioned here again reduces the forces required for lifting, depending on the number of rollers provided. According to the pulley principle, the forces required can be reduced considerably, at least halved.

Belts, ropes, chains or the like can be used as special traction devices. In any case, the traction device must be firmly connected to one of the carriages, carriages or the like via the deflection rollers assigned to the carriage, slide or the like in such a way that when the traction device is pulled, the two carriages, slides or the like are moved towards each other in the same way, under the influence of the respective removal roller on the curve surface. A safe lifting movement of the scissor mechanism is thus achieved with the simplest construction.

In the above explanations, it was assumed that the drive means are assigned to only one pair of scissor links. If the scissor lift table according to the invention is intended to lift heavy loads in particular, it is advantageous if the drive means and rails are assigned to both pairs of scissor links. In such a case, the carriages, sledges or the like could engage via a yoke in the rails arranged on the inside of both scissor links by means of the guide elements, preferably by means of ball-bearing rollers. Accordingly, removal rollers for rolling on the curves could be provided on both sides of the yoke. In such a design, the yoke could carry the deflection roller, which is preferably arranged centrally between the scissor links, and this can be designed to be sufficiently wide to accommodate several traction means at the same time. The use of two or three traction means, which are arranged parallel to one another and preferably run together over the same deflection rollers, would be conceivable and would also bring with it an increased level of operational reliability. Even if a single traction device is destroyed, the other or the others could still work sufficiently.

Furthermore, it is conceivable that the scissor mechanism comprises several pairs of scissor links arranged next to each other or one above the other. In this respect, a kind of two-story design of the scissor mechanism could be realized in order to be able to achieve very considerable lifting heights. If the pairs of scissor links are arranged one above the other, the scissor mechanism could be driven together, whereby the pairs of scissor links can be operated via common traction means.

With regard to operational safety, it is also advantageous if special monitoring means are provided to monitor functionality, in particular to ensure sufficient operational safety. These monitoring means could include detectors that monitor the tensile force and/or detectors that directly monitor the traction means. If a malfunction is detected, in particular damage to the traction means and/or the scissor mechanism, the drive could be switched off automatically. In a further advantageous manner, if such a detection is made, the scissor mechanism is locked or blocked in its position, so that lowering of the table due to damage is effectively prevented.

The drive, in particular the drive for the traction mechanism, could be designed as an electric motor, although pneumatic or hydraulic actuation is also conceivable. Regardless of the specific design of the drive, it could be assigned to the lower frame or be located outside the frame or away from the actual scissor lift table.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. For this purpose, reference is made on the one hand to the claims subordinate to claim 1 and on the other hand to the following explanation of an embodiment of the invention with reference to the drawing. In connection with the explanation of the preferred embodiment of the invention with reference to the drawing, generally preferred embodiments and developments of the teaching are also explained. The drawing shows

Fig. 1 shows a schematic side view of an embodiment of a

scissor lift table according to the invention, wherein the table is raised,

Fig. 2 shows a schematic side view of the object from Fig. 1 at

lowered table,

Fig. 3 in a schematic plan view, partially, the scissor lift table from

Fig.1,

Fig. 4 in a schematic view of the drive means for actuating

the scissor links serving wagon with yoke and

Fig. 5 the arrangement of Fig. 4 in engagement with the guide

Rail.

Fig. 1 and 2 show - in the extended and retracted state of the lifting mechanism - a scissor lifting table with a lower frame 1, an upper frame 3 forming a working level or a table 2 and a scissor mechanism 4 acting between the lower frame 1 and the upper frame 3, wherein the scissor mechanism 4 comprises intersecting inner scissor links 5 and outer scissor links 6, which can be actuated to raise or lower the upper frame 3. In the embodiment selected here, both pairs of intersecting scissor links 5, 6 are assigned drive means 7, wherein Fig. 1 and 2 only shows one pair of the inner and outer scissor links 5, 6.

According to the invention, two curves 8 are assigned to one scissor link - the outer scissor link 6 - and two carriages 9 which can be moved along the scissor link 5 on the curves 8 towards and away from each other are assigned to the other scissor link - the inner scissor link 5 - as drive means 7.

In Fig. 1 and 2 it is further indicated that the scissor members 5, 6 are connected at one end to the frames 1, 3 in a stationary and pivotable manner. With the other ends, the scissor members 5, 6 engage displaceably in the frames 1, 3 in order to be able to realize the scissor movement. Special guides 10 are provided for this purpose.

Fig. 2 shows particularly clearly that the carriages 9 are positioned or arranged in such a way that when the upper frame 3 or the table 2 is lowered, they rest on the curves 8 on both sides in the edge area. Due to this arrangement, the lifting movement is initiated even with a slight movement of the carriages 9.

Fig. 1 and 2 also show together that the carriages 9 can be moved towards one another on the curves 8 via a drive 11 (only indicated) along the inner scissor link 5 that guides the carriages 9 to raise the upper frame 3, and can be moved away from one another by gravity to lower the upper frame 3. If the drive 11 is therefore switched off or the load is relieved, the carriages 9 can move back along the curved surfaces 12 due to gravity, so that the upper frame 3 is lowered.

Figures 1 and 2 further show that the two curves 8 are arranged on both sides of the intersection point 13 of the scissor links 5, 6 on the outer scissor link 6. The curves 8 are at least slightly spaced from the intersection point 13.

With regard to the modifiability or interchangeability of curves 8, reference is made to the general description to avoid repetition. The same applies to the associated influence on the kinematics or dynamics of the lifting/lowering movement.

Figures 1 and 2 show particularly clearly that the two curves 8 with their active or running surfaces 12 are arranged on opposite sides of the outer scissor member 6, so that the carriages 9 assigned to the inner scissor member 5 run on opposite sides. This results in a particularly stable construction.

In Fig. 1 to 5 it is generally indicated that the carriages 9 run in a rail 14 associated with the respective scissor link - inner scissor link 5. In the embodiment shown in the figures, the rail 14 is U-shaped in cross-section and is provided on the side of the inner scissor link 5 - on the respective inner side. In concrete terms, the carriage 9 can roll in the rail 14, with a very special guide 15 being provided for this purpose. This is indicated in Fig. 5.

The figures also show that the carriages 9 each have a ball-bearing removal roller 16 for rolling on the curve 8. This can be seen particularly clearly in Figs. 1, 4 and 5.

The carriages 9 also each comprise a deflection roller 17 and holding means 18 for securing a traction means 19, wherein the traction means 19 - here in the form of a belt - is guided over the deflection rollers 17 to the holding means 18 in such a way that the pulley principle applies to reduce the forces required for lifting. In this respect, too, reference is made to the introduction to the description to avoid repetition.

Fig. 3, 4 and 5 show particularly clearly that the drive means 7 and the guide rails 14 are assigned to both pairs of scissor links 5, 6. The carriages 9 are equipped with a yoke 20 so that the rails 14 can be engaged on both sides to guide the carriage 9. The engagement takes place via the guide elements 15, on both sides of the yoke 20, as described above.

Fig. 5 indicates that the guide elements 15 are designed as rollers 21. On both sides of the yoke 20, removal rollers 16 are provided for rolling on the curves 8, which can be seen particularly clearly in Figs. 3, 4 and 5. Figs. 3, 4 and 5 also clearly show that the yoke 20 carries the deflection roller 17 arranged centrally between the scissor members 5, 6, which is designed to be sufficiently wide, namely to accommodate or deflect one or more traction means 19.

Finally, it should be noted that in the embodiment chosen here, only a belt 19 is provided as a traction means, which - symbolically indicated in Fig. 1 - runs over a drive 11 assigned to the lower frame 1. The drive, for example an electric motor, could also be arranged outside the lower frame 1, so that a connection or coupling from outside is required.

Finally, it should be particularly emphasized that the embodiment discussed above serves to illustrate the claimed teaching by way of example, but does not limit it to the embodiment.

List of reference symbols

1 lower frame 2 Table 3 upper frame 4 Scissor mechanism 5 inner scissor links 6 outer scissor joints 7 Propulsion system 8th Curve 9 Dare 10 Guide (of the scissor links in the frame) 11 drive 12 Curve surface, effective/running surface 13 Crossing point of the scissor links 14 rail 15 Guide, guide element (in the rail) 16 Removal roller 17 Pulley 18 Holding device (on the car) 19 Traction devices, belts 20 yoke 21 Roller (guide element)

Claims (34)

1. Scissor lift table with a lower frame ( 1 ), an upper frame ( 3 ) forming a work surface or a table ( 2 ), and a scissor mechanism ( 4 ) acting between the lower frame ( 1 ) and the upper frame ( 3 ), wherein the scissor mechanism ( 4 ) comprises intersecting inner and outer scissor links ( 5 , 6 ) which can be actuated to raise or lower the upper frame ( 3 ), and wherein at least one pair of the intersecting scissor links ( 5 , 6 ) is assigned drive means ( 7 ), characterized in that two curves ( 8 ) are assigned to one scissor link ( 6 ) and two carriages ( 9 ), slides or the like which can be moved along the scissor link on the curves ( 8 ) towards and away from each other are assigned to the other scissor link ( 5 ) as drive means ( 7 ). 2. Scissor lift table according to claim 1, characterized in that the carriages ( 9 ), slides or the like are positioned such that they rest on the curves ( 8 ) on both sides in the edge region when the upper frame ( 3 ) is lowered. 3. Scissor lift table according to claim 1 or 2, characterized in that the carriages ( 9 ), slides or the like can be moved towards one another on the curves ( 8) via a drive (11 ) along the scissor member ( 5 ) guiding the carriages ( 9 ), slides or the like in order to raise the upper frame ( 3 ), and can be moved away from one another, preferably via gravity, in order to lower the upper frame ( 3 ). 4. Scissor lift table according to one of claims 1 to 3, characterized in that the two curves ( 8 ) are arranged on both sides of the intersection point of the scissor links ( 5 , 6 ), preferably at least slightly spaced from this, on the respective scissor link ( 5 , 6 ). 5. Scissor lift table according to one of claims 1 to 4, characterized in that at least one of the two curves ( 8 ) can be changed in its position on the scissor member ( 6 ). 6. Scissor lift table according to one of claims 1 to 5, characterized in that the curves ( 8 ) can be changed in their position along the scissor member ( 6 ) and/or in their angular position to the scissor member ( 6 ). 7. Scissor lift table according to one of claims 1 to 6, characterized in that the curves ( 8 ) are exchangeable. 8. Scissor lift table according to one of claims 1 to 7, characterized in that the curves ( 8 ) with their predeterminable curve shape serve to influence the kinematics and dynamics of the lifting/lowering movement. 9. Scissor lift table according to one of claims 1 to 8, characterized in that the curves ( 8 ) are designed such that at a constant speed of the drive ( 11 ) the upper frame ( 3 ) or the table ( 2 ) is raised and/or lowered at a constant speed. 10. Scissor lift table according to one of claims 1 to 9, characterized in that the two curves ( 8 ) with their active or running surfaces ( 12 ) are arranged on opposite sides of the scissor member ( 6 ), so that the carriages ( 9 ), slides or the like run on opposite sides. 11. Scissor lift table according to one of claims 1 to 10, characterized in that the carriages ( 9 ), slides or the like run in a rail ( 14 ) assigned to the respective scissor link ( 5 ). 12. Scissor lift table according to claim 11, characterized in that the rail ( 14 ) is U-shaped in cross section. 13. Scissor lift table according to claim 11 or 12, characterized in that the rail ( 14 ) is provided laterally on the scissor member ( 5 ), preferably on the inside. 14. Scissor lift table according to one of claims 11 to 13, characterized in that the carriages ( 9 ), slides or the like are displaceable in the rail ( 14 ). 15. Scissor lift table according to one of claims 11 to 13, characterized in that the carriages ( 9 ), slides or the like roll in the rail ( 14 ). 16. Scissor lift table according to claim 15, characterized in that the carriages ( 9 ), slides or the like have guide elements ( 15 ) serving to engage in the rail ( 14 ). 17. Scissor lift table according to claim 16, characterized in that the guide elements ( 15 ) are designed as preferably ball-bearing rollers ( 21 ). 18. Scissor lift table according to one of claims 1 to 17, characterized in that the carriages ( 9 ), slides or the like each have at least one preferably ball-bearing removal roller ( 16 ) for rolling on the curve ( 8 ). 19. Scissor lift table according to one of claims 1 to 18, characterized in that the carriages ( 9 ), slides or the like have holding means ( 18 ) and/or at least one deflection roller ( 17 ) for a traction means ( 19 ). 20. Scissor lift table according to claim 19, characterized in that the traction means ( 19 ) from the drive ( 11 ) connects the two carriages ( 9 ), slides or the like to one another via their holding means ( 18 ) and via the deflection rollers ( 17 ) in such a way that when the traction means ( 19 ) is pulled, the two carriages ( 9 ), slides or the like - rolling on the curves ( 8 ) - can be moved towards one another under the effect of a pulley system. 21. Scissor lift table according to claim 20 or 21, characterized in that a belt ( 19 ), a rope, a chain or the like serves as the traction means ( 19 ). 22. Scissor lift table according to one of claims 19 to 21, characterized in that the drive means ( 7 ) together with rails ( 14 ) are assigned to both pairs of scissor links ( 5 , 6 ) and that the carriages ( 9 ), slides or the like engage via a yoke ( 20 ) in the rails ( 14 ) arranged on the inside of both scissor links ( 5 , 6 ) by means of the guide elements ( 15 ), preferably by means of ball-bearing rollers ( 21 ). 23. Scissor lift table according to claim 22, characterized in that removal rollers ( 16 ) for rolling on the curves ( 8 ) are provided on both sides of the yoke ( 21 ). 24. Scissor lift table according to claim 22 or 23, characterized in that the yoke ( 20 ) carries the deflection roller ( 17 ) preferably arranged centrally between the scissor members ( 5 , 6 ). 25. Scissor lift table according to one of claims 22 to 24, characterized in that two or three traction means ( 19 ) are arranged parallel to one another and preferably run together over the same deflection rollers ( 17 ). 26. Scissor lift table according to one of claims 1 to 25, characterized in that the scissor mechanism ( 4 ) comprises pairs of scissor links ( 5 , 6 ) arranged one above the other. 27. Scissor lift table according to claim 26, characterized in that the pairs of scissor links arranged one above the other have a common drive ( 11 ). 28. Scissor lift table according to claim 26 or 27, characterized in that the scissor link pairs ( 5 , 6 ) can be actuated via common traction means ( 19 ). 29. Scissor lift table according to one of claims 1 to 28, characterized in that special monitoring means are provided for monitoring the functionality, in particular for ensuring sufficient operational safety. 30. Scissor lift table according to claim 29, characterized in that the monitoring means comprise detectors monitoring the tensile force and/or detectors directly monitoring the traction means ( 17 ). 31. Scissor lift table according to claim 29 or 30, characterized in that upon detection of a malfunction, in particular damage to the traction means ( 19 ) and/or the scissor mechanism ( 4 ), the drive ( 11 ) can be switched off automatically and the scissor mechanism ( 4 ) can be locked or blocked in its position. 32. Scissor lift table according to one of claims 1 to 31, characterized in that the drive ( 11 ), in particular the drive ( 11 ) for the traction means ( 19 ), is designed as an electric motor. 33. Scissor lift table according to one of claims 1 to 32, characterized in that the drive ( 11 ) operates pneumatically or hydraulically. 34. Scissor lift table according to one of claims 1 to 33, characterized in that the drive ( 11 ) is assigned to the lower frame ( 1 ).