EP1375409B1 - Scissors lift device for a roller conveyor installation - Google Patents

Description

The invention relates to a lifting device with a base frame and a raised and lowered support frame on which a load is turned off. For horizontal guidance of the raised and lowered support frame relative to the base frame is a scissor device which is supported on the base frame, having a central scissor shaft and acting parallelführend on the support frame, wherein the eccentric lifting device is arranged approximately centrally between the base and support frame.

A device of the type indicated above is known from GB-A-1, 487, 119. The document discloses a lifting device with a platform movable up and down. To perform this lifting and lowering scissor arms are provided, which interact with length-adjustable lifting means and a rotatable swing arm. In this case, the swing arm and the scissor arms have the same axis of rotation, while the lifting means are each in operative connection with one end of the swing arm.

The document US-A-5,829,948 discloses a lifting device also with scissor arms, wherein on the liftable and lowerable support frame a roller conveyor is arranged.

In the also belonging to the prior art document is a lifting table with a so-called "Nuremberg scissors" described. To drive the scissor axes carrying a table top, one or two separate drive levers are used. These are designed in the form of a Tangentialnocke and act on pressure rollers, which are attached to the lower regions of the legs of the scissor members. At the base of the tangential cam of a drive lever, a sprocket is mounted in each case, over which a chain is guided. One end is attached to the base frame and the other end to the sprocket of a tangential cam. The sprocket can be in horizontal Direction to be unrolled on the chain. The thus caused rotation of the tangential cam of the associated drive lever is transmitted via the pressure roller on the leg of one of the scissor members, thereby causing an opening and closing of the scissor members and thus an increase or decrease of the run of the scissor members table top. Due to the shape of the tangential cam, it is possible to open the scissor members with approximately constant torque. Nevertheless, the overall structure of the device, in particular due to the unwinding of the drive lever via a chain held firmly on both sides, is not suitable for the rapid lifting and lowering of particularly heavy loads.

From the German Utility Model G 85 28 803.9 a "lift with each track at least one scissors-lifting device" is known. In this case, the strut parts of the scissors are preferably designed as telescopically nested tube parts. The longer-dimensioned leg strut has a translational drive operating at least substantially in its longitudinal direction. This is designed in particular in the form of a hydraulic or pneumatic lifting cylinder. The lifting force is thus introduced in the longitudinal direction in the longer leg strut. It can be provided an additional working cylinder which engages the scissors joint. This acts as additional Hubkraftunterstützung or in the lowering phase as damping. Also, this device is not suitable for rapid lifting and lowering of particularly heavy loads, in particular due to the unilateral lifting force in a leg of the scissors.

Furthermore, from German Utility Model G 94 15 656.5 a lifting table known. This has a bottom frame, a table top, a parallel guide for the table top and an attacking on the bottom frame and table top lifting device. The lifting device has at least one circular segment-shaped lifting member with circular arc-shaped guideway. Which is provided with drive means. The lifting member is with his guideway on guide means on the bottom frame along the guideway movable and mounted drivable. In this case, the upper end of the lifting member matured as a result of guide elements slidably on the table top or its parallel guide. Since in this device up to four circular segment-shaped lifting members are required, which act on the corners of the table top and must be driven evenly, a special design effort is required in particular for the control of the moving masses.

The invention is based on the object to provide a lifting device that allows a fast lifting and lowering of particularly heavy loads with an efficient power transmission to the support frame without a complex construction.

The object is achieved with specified in claim 1 lifting device.

It has a base frame, a lifting and lowering support frame and a scissor device, which is supported on the base frame and acts on the support frame via a central scissor shaft in parallel. Furthermore, an eccentric lifting device with an eccentric lever is provided which is mounted on the scissor shaft so that it rotates symmetrically in a basic position between the base and support frame and supported upon rotation about the scissors shaft for raising or lowering the support frame on basic and supporting frame is. In this case, the eccentric lifting device is arranged substantially centrally between the base and support frame. In addition, the eccentric lever rollers, which act on raising and lowering of the support frame on base and support frame.

The device according to the invention is particularly characterized in that the eccentric lever of the eccentric lifting device on the one hand centrally on the scissor shaft of the scissor device is mounted and on the other hand, the eccentric lever, in particular via its ends by force directly supported on the base frame and the support frame. This has the effect that the scissor arms of the scissors device do not have to transmit any lifting and lowering forces, but serve exclusively for the horizontal parallel guidance of the support frame relative to the base frame. The entire load is fed in and out via the rotatable eccentric lever. Furthermore, the introduction of the driving forces due to the central arrangement of the eccentric lever on the scissor shaft takes place in an ideal manner, so that a symmetrical load distribution is achieved. It is of great importance for the effectiveness of the lifting device that the power is transmitted to the support frame via rollers on the eccentric lever.

Since in the lifting device according to the invention, in contrast to the prior art, no forces are introduced into the scissor arms, the eccentric lever of the Exzenterhebeeinrichtung can be dimensioned so that even the heaviest loads can be quickly lifted or lowered. on the other hand are the to be moved during the rotation of the eccentric lever masses only small. Advantageously, the shaft of the scissor device quasi taken by the central rotatably mounted eccentric lever in addition to the actual increase or decrease of the support frame and the loads resting thereon, while causing the parallel guidance of the support frame.

In a preferred development of the invention, the eccentric lifting device has a chain drive. This is advantageously arranged in the longitudinal direction parallel to the scissor device. The chain drive advantageously comprises a drive unit which is attached to an end face of the base frame. The chain drive advantageously includes a sprocket, which is connected to the scissor shaft with the eccentric lever and over the parallel to the scissor device a closed drive chain, the sprocket is guided.

Advantageous further embodiments of the invention are specified in the subclaims.

Fig. 1

eine beispielhafte Ausführung einer Hubvorrichtung gemäß der vorliegenden Erfindung in einer Seitenansicht, wobei die Hubvorrichtung in einen oberen Totpunkt ausgefahren ist,

Fig. 2

die Hubvorrichtung gemäß dem Ausführungsbeispiel von Figur 1, wobei diese in einen unteren Totpunkt eingefahren ist, und

Fig. 3

die in den oberen Totpunkt ausgefahrene Hubvorrichtung gemäß dem Ausführungsbeispiel von Figur 1 in einer Draufsicht auf die hintere Stirnseite.

In the following, a preferred embodiment of the invention will be explained in more detail with reference to the drawings. Show it:

Fig. 1

an exemplary embodiment of a lifting device according to the present invention in a side view, wherein the lifting device is extended to a top dead center,

Fig. 2

the lifting device according to the embodiment of Figure 1, wherein this is retracted to a bottom dead center, and

Fig. 3

the extended to the top dead center lifting device according to the embodiment of Figure 1 in a plan view of the rear end side.

Fig. 1 shows an example of a particularly advantageous embodiment of a lifting device according to the present invention in a side view, wherein the lifting device is extended to a top dead center, i. the maximum constructively possible lifting height occupies.

The basic frame of the embodiment shown in Figure 1 has a first and second side members 11, 12, wherein the longitudinal member 11 is located in the plane of the drawing and the longitudinal member 12 behind the drawing plane. The longitudinal members are connected by corresponding cross struts firmly together.

Between the rear end face 11b of the first longitudinal member 11 and the rear end face 12b of the second longitudinal member 12, a drive unit 3 is mounted on the base frame. This preferably has a drive motor 31 with a downstream transmission 32. On the central drive shaft 33 of the transmission 32, which extends transversely to the longitudinal members 12,13, on the one hand a drive pinion 34 for a closed, circumferential drive chain 35 of the drive unit 3 is mounted. On the other hand, the drive shaft 33 additionally serves as a stationary, rotatable bearing point of the lower rear end of the scissor device 4.

The scissor device 4 consists in the example shown in Figures 1 to 3 of a front and a rear pair of scissors 41, 42. Again, the front pair of scissors 41 is in the plane and the rear pair of scissors 42 behind the plane. The front pair of scissors 41 has a first front scissor arm 411 and a second front scissor arm 412, which are rotatably connected to each other via the central scissor shaft 43. The rear pair of scissors 42, which is visible in the side view of Figure 3, has a first rear scissor arm 421 and a second rear scissor arm 422, which are rotatably connected to each other via the central scissors shaft 43.

The support frame 2 of the embodiment shown in Figure 1 has a first and second side members 21, 22, wherein the longitudinal member 21 in the drawing plane and the longitudinal member 22 in turn lies behind the plane of the drawing. The longitudinal members 21,22 are also firmly connected by corresponding cross struts.

At the rear end faces 21b, 22b of the first and second longitudinal members 21,22 are on the undersides of the support frame 2 fixed points for stationary, rotatable mounting of the upper, rear end of the scissor device 4. As can be seen from Figure 1, is an upper fixed bearing block 213 on the rear end face 21b of the first side member 21 is present. On the rotary shaft 214 in the upper bearing block 213, the upper, rear end of the second front scissor arm 412 of the front pair of scissors 41 is rotatably mounted. As can be seen from the side view of Figure 3, in a corresponding manner, an upper fixed bearing block 223 on the rear end face 22b of the second longitudinal member 22 is present. On the rotary shaft 224 in the upper bearing block 223, the upper, rear end of the second rear scissor arm 422 of the rear pair of scissors 42 is rotatably mounted.

At the opposite front end faces of base and support frame 1.2, the corresponding ends of the scissor arms of the scissor device 4 are rotatably mounted and linearly displaceable.

As can be seen from FIG. 1, a lower linear guide 110 is mounted on the front end face 11a on the first side member 11 of the base frame 1. In this, a lower bearing block 111 is guided, on the rotary shaft 112, the front lower end of the scissor arm 412 of the pair of scissors 41 is rotatably and linearly displaceably mounted. As can be seen from the side view of Figure 3, is in a corresponding manner at the front end face 12a on the second side member 12 of the base frame 1, a lower linear guide 120 attached. In this, a lower bracket 121 is guided, on the rotary shaft 122, the front lower end of the scissor arm 422 of the pair of scissors 42 is also mounted rotatably and linearly displaceable.

As can be seen further from FIG. 1, an upper linear guide 210 is attached to the front end face 11a on the first longitudinal member 21 of the support frame 2 in a corresponding manner. In this an upper bearing block 211 is guided, on the rotary shaft 212, the front upper end of the scissor arm 411 of the pair of scissors 41 is rotatably and linearly displaceably mounted. As can be seen from the side view of Figure 3, an upper linear guide 220 is mounted in a corresponding manner on the front end face 22a on the second side member 22 of the support frame 2. In this an upper bearing block 221 is guided, on whose rotary shaft 222, the front upper end of the scissor arm 421 of the pair of scissors 42 is also mounted rotatably and linearly displaceable.

The eccentric lifting device 5 of the lifting device according to the invention has an eccentric lever 55 which is mounted rotatably on the central scissor shaft 43 approximately in the center of the lifting device. In the example shown, the eccentric lever 55 is rectilinearly stretched and executed symmetrically. He has two approximately equally long legs, one of which is supported on the base frame 1 and the other acts on the underside of the support frame 2. Depending on the particular application, it is not excluded in exceptional cases that the two legs of the eccentric lever 55 have divergent shapes. On the other hand, the embodiment shown in Figures 1 to 3 in particular of the force distribution, the movement and the structural design forth preferred.

Vorteihaft for the eccentric lever 55 of the Exzenterhebeeinrichtung 5 each rotations to plus or minus 90 degrees. FIG. 1 shows a state in which the eccentric lever 55 rests quasi-perpendicular in the manner of a column between the base and support frame. The lifting device according to the invention is located at top dead center and has reached the maximum lifting height. It can be clearly seen that the eccentric lever 55 receives the entire load from the support frame 2 and leads directly to the base frame 1. The scissor device 4 has only the task of ensuring the parallel, preferably horizontal position of the support frame 2 relative to the base frame 1. To lower the support frame, the eccentric lever 55 must be turned 90 degrees to the right or left.

Fig. 2 shows this position of the lifting device, wherein this is retracted into a bottom dead center. The eccentric lever 55 now rests in a basic position between the base and support frame. The lifting device according to the invention is now at bottom dead center and has reached the minimum lifting height.

In particular, in the event that very high loads rest on the support frame, which may need to be raised or lowered at a very high clock rate, it is advantageous if at the ends of the eccentric lever 55, a first and second rollers 551, 552 attached are. These can attack directly on corresponding upper sides of the base and support frame 1, 2. In the embodiment shown in Figures 1 to 3, on the one hand approximately in the middle between the first and second side members 11, 12 of the base frame 1, a lower running rail 510 is present, which is covered with a lower running surface 511. The rolling behavior and thus the power transmission between the roller 551 and the top of the base frame 1 can thus be significantly improved. In a corresponding manner, on the other hand approximately in the middle between the first and second side members 21, 22 of the support frame 2, an upper running rail 520 is present, which is covered with an upper running surface 521. The rolling behavior and thus the power transmission between the roller 552 and the underside of the support frame 1 can thus be significantly improved.

As already shown in the exemplary embodiments of FIGS. 1 to 3, the eccentric lifting device 5 of the lifting device according to the invention is advantageously arranged in the space between the pairs of scissors 41, 42 of the scissor device 4. Furthermore, the drive device for the eccentric lever 55 of the eccentric lifting device 5 is advantageously designed in the form of a chain drive. The chain drive is arranged in the longitudinal direction parallel to the scissor device. In this case, the chain drive on the one hand on a sprocket 56 which is connected to the scissor shaft 43 with the eccentric lever 55. On the other hand, the drive pinion 34 on the central drive shaft 33 of the transmission 32 is another part of the chain drive. The power transmission between the drive pinion 34 and sprocket 56 is accomplished via a closed drive chain 35, which is parallel to the scissor device 4 via the sprocket 56, accomplished.

The central scissor shaft 43 thus represents an essential Bestanteil the lifting device according to the invention. In addition to the function of the rotatable mounting of the scissor arms of the two pairs of scissors it thus also serves the rotatable mounting of eccentric lever 55 and sprocket 56th

FIG. 3 shows the lifting device extended into top dead center according to the exemplary embodiment of FIG. 1 in a plan view of the rear end face. Thus, inter alia, the rear end faces 11b, 12b of the longitudinal members 11, 12 of the base frame 1 and the rear end faces 21b, 22b of the longitudinal members 21, 22 of the support frame 2 can be seen. Furthermore, the view in the foreground shows the drive unit 3. The underlying lower running rail 510 with the lower running surface 511 located thereon is thereby concealed. In contrast, the upper running rail 520 can be seen clearly on the support frame 2. To improve stability, the running surfaces 521 in the form of two parallel rails are made in two parts. Accordingly, the second roller 552 is designed in the form of a double role.

The invention has the advantage that a fast lifting and lowering of particularly heavy loads is made possible without a complex construction. The lifting device according to the invention can thus be used particularly in completely automated production plants or transfer lines. As an exemplary application case, the use in the automotive industry is to be cited. There, body shells are transported from processing station to processing station with the aid of what are known as skid conveyor systems. It may be necessary for each processing station to lower the body shell to be machined to a working level and to raise it again to the conveying level after machining has taken place. The lowering and lifting operations must be in spite of the condition of the body dependent and u.U. already high own weight with the highest possible speed.

Thus, in the example shown in Figures 1 to 3 on the support frame 2 in addition a roller conveyor 6 is launched. This has at least one lying in the plane of Figures 1 and 2 first guide wall 61 and a second guide wall 62 lying behind. In the guide walls 61,62 pairs opposing carrying rollers 64 are mounted on which skids can be funded. Laterally, a roller conveyor drive 63 is placed for driving the support rollers 64.

Claims (12)

1. Lift device with

   a) a base frame (1),

   b) a carrier frame (2) that can be raised and lowered,

   c) a scissors device (4), which is supported on the base frame (1), features a central scissors shaft (43) and acts as a parallel guide on the carrier frame (2), and with

   d) an eccentric lifting device (5) with an eccentric lever (55), which is essentially supported so as to rotate symetrically around the scissors shaft (43), that this rests in a basic position between base frame and carrier frame (1,2) and when rotating around the scissors shaft (43) to raise or lower the carrier frame (2) is supported on the base frame and the carrier frame (1,2), with the eccentric lifting device (5) being essentially arranged midway between the base and the carrier frame (1,2), characterized in that the eccentric lever (55) features rollers (551,552) which, when the carrier frame (2) is raised and lowered, act on the base frame and the carrier frame (1,2).
2. Lift device in accordance with claim 1,
   characterized in that base frame and carrier frame (1,2) feature bars (510,520) on which the eccentric lever (55) acts when raising or lowering the carrier frame (2).
3. Lift device in accordance with claim 2,
   characterized in that the bars (510,520) are equipped with conveyor surfaces (511,521).
4. Lift device in accordance with one of the previous claims,
   characterized in that the eccentric lifting device (5) features a chain drive (3,56).
5. Lift device in accordance with claim 4,
   characterized in that the chain drive (3,56) is arranged in a longitudinal direction in parallel to the scissors device (4).
6. Lift device in accordance with claim 4 or 5,
   characterized in that the chain drive (3,56) features a drive unit (3) which is accommodated on an end face (11b,12b) of the base frame (1).
7. Lift device in accordance with claim 4, 5 or 6,
   characterized in that the chain drive (3,56) features a chain wheel (56) which is connected on the scissors shaft (43) to the eccentric lever (55).
8. Lift device in accordance with claim 7,
   characterized by
   a closed drive chain (35) which is routed in parallel to the scissors device (4) over the chain wheel (56).
9. Lift device in accordance with one of the previous claims,
   characterized in that the scissors device (4) features two pairs of scissors (41,42) connected to the central scissors shaft(43).
10. Lift device in accordance with claim 9,
    characterized in that the eccentric lifting device (5) is arranged in the space between the scissor pairs (41,42) of the scissors device (4).
11. Lift device in accordance with one of the previous claims,
    characterized in that the ends of a scissor pair (41;42)

    a) on one end face (11b,21b;12b,22b) of the lifting device are connected in a fixed position (33,213;33,223) and rotatably (33,214;33,224) to the base frame and the carrier frame (1,2), and

    b) on the opposite end face (11a,21a; 12a,22a) of the lifting device are connected in a linearly movable manner (110,210;120,220) and rotatably (112,212;122,222) to the base and carrier frame (1,2) .
12. Lift device in accordance with one of the previous claims,
    characterized in that, a conveyor (6) is arranged on the carrier frame (2).

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