DE9218058U1 - Platform trestle for constructing theatre stages or similar. - Google Patents

Description

G 9k 18 058.2

ÜM 5 500a/92

Utility model

Applicant: Hans-Jochen Eisenberg 5600 Wuppertal 2

Platform trestle for setting up theatre stages or similar.

The invention relates to a platform trestle for the construction of theater stages, stands or the like, with a platform supported by two X-shaped lifting scissors and with a motorized spindle drive that engages the scissor legs of the lifting scissors in order to raise them from a flat basic position into a steep extended position, the movable scissor legs being mounted on rollers.

To build theater stages or similar, a large number of such platform trestles, such as those known from DE 29 41 912 A1, are placed directly next to one another. In order to be able to stack the platform trestles in a space-saving manner when not in use, efforts are made to keep the base height to which a platform trestle can be lowered as low as possible. The same requirement is placed on such platform trestles if they are to be used to permanently cover a hall floor. The lower the base height of the platform trestles, the better they can be adapted to adjacent floor areas, e.g. in corridors or entrance areas. However, with platform trestles that are folded very flat, where in extreme cases the legs L are parallel to one another, raising them using a spindle drive is extremely problematic, since the scissor legs in such a case do not yet have a

Lever arm for the engagement of the adjustment spindle. It is known (EP O 034 221 B1) to provide platform trestles with a starting aid in the form of pre-tensioned compression springs, but this starting aid is not very effective.

GB-A 915 556, DE-A 3 442 940, US-A 1 794 165, CH-A 276 815 and EP-A 0 286 615 disclose lifting tables constructed using X-scissors, the height of which can be adjusted using a motor drive, e.g. hydraulic or electric. To overcome the flat dead center position of the scissors, the motor drives there are each equipped with an auxiliary lifting device , by means of which the lifting tables are initially raised over an initial path, after which the drive takes over the complete erection of the lifting tables. These known lifting tables are very complex and expensive due to the often considerable load they have to lift, so that they are practically unsuitable for the construction of theater stages or the like, where a large number of platform trestles are required. In addition, the known lifting tables are designed to support stationary loads that are generally evenly distributed across their table surface, while groyne platform trestles are subjected to completely irregular and usually only point-like loads by the people working on them. With groyne platform trestles, it is essential that their platforms maintain their exact horizontal height even under such irregular loads, so that tripping edges between neighboring platform trestles are avoided.

The invention is based on the task of creating a motor-driven height-adjustable platform for the construction of theater stages or the like, which is inexpensive

can be manufactured and which, in particular, ensures that the platform remains even and horizontally aligned under different loads.

To solve this problem, the invention provides

a) that in the area of the platform centre below the platform there is an auxiliary lifting device which can also be driven by the motor spindle drive,

b) that the spindle drive, when the motor is switched on in the flat platform st bockgrundste L Lung, initially only operates the auxiliary lifting direction, which raises the platform trestle by an initial stroke, whereby during this initial phase the attack of the

Spindle drive on the scissor legs Ln is running idle,

c) that only towards the end of the initial phase does the spindle drive act on the scissor arm L and continues to raise the platform trestle, during which time the auxiliary lifting device runs idle,

d) that the motor drives two parallel horizontal spindles, each running next to the X-shaped scissors,

e) that the X-shaped scissors are each firmly hinged to the corners of the platform trestle on one transverse side of the platform trestle and that the opposite movable scissors legs extend to the corners of the other transverse side of the platform trestle in the flat basic position of the platform trestle ,

f) that a cross-beam is mounted on the axes of the rollers of the lower, movable scissor leg ends, on which the spindle drive acts after its idle run in order to move these scissor leg ends

to be pulled directly towards the fixed lower scissor jib I ends,

g) that the Hi Ifs lifting device consists of ramps and associated ramps and

h) that either a ramp is arranged near the scissor joint on each scissor leg and the associated ramp is attached to the spindle drive or that the ramps are arranged near the scissor joint on each of the scissor legs and the associated ramp is attached to the spindle drive.

The invention offers a number of advantages. Firstly, the platform trestle can now be designed with a minimal base height, so that it meets the requirements for low stacking heights or low application heights when subsequently covering a hall floor.

The auxiliary lifting device enables the platform trestle to be raised safely and reliably from its lowest position with little effort and also lowered back to its basic position in a controlled manner. When using a motor gear with brake and a self-locking spindle drive or when using a step brake motor, the platform trestle can be adjusted continuously to any desired height so that it can be adjusted exactly to adjacent platform trestles or to the adjacent floor areas, for example to an adjacent stair step. Due to its construction, the platform maintains its horizontal position and height exactly even when the load is unevenly distributed, which is of crucial importance for platforms or similar with regard to avoiding tripping edges. Another advantage of the

Invention that the auxiliary lifting device requires only a few, inexpensive additional devices, since the basic structure of the generic platform trestle remains unchanged.

Further features of the invention are specified in the subclaims and explained in more detail below in conjunction with the description of the figures.

The subject matter of the invention is described in more detail below using several embodiments shown in the drawing. In the drawing:

Fig. 1 in a longitudinal section along the line I-I in Fig. 4 a first embodiment of a platform trestle according to the invention, in its lowest basic position,

Fig. 2 the platform trestle in an intermediate position, to which the platform trestle is raised using the auxiliary lifting device,

Fig. 3 the platform trestle in its highest position,

Fig. 4 a top view of the platform trestle in a position according to Fig. 1, with the platform and upper frame omitted,

Fig. 5 a second embodiment of a

Platform trestle according to the invention, namely in a plan view of the platform trestle in its lowest basic position, with the platform and upper frame omitted.

Fig. 6 shows an enlarged detail of the platform frame according to Fig. 5,

Fig. 7 is a section along line VII in Fig. 5,

Fig. 8 another detail of the platform frame according to Fig. 5,

Fig. 9, 10 and 11 show longitudinal sections of the platform frame according to Fig. 5 in three different height settings,

Fig. 12 a third embodiment in a lateral detailed view of the platform trestle,

Fig. 13 a fourth embodiment in plan view,

Fig. 14 to 19 show a simplified side view of a fifth embodiment of the platform trestle according to the invention in six different lifting heights,

Fig. 20 to 22 a sixth embodiment in a simplified side view, whereby the platform trestle is shown in three different lifting heights and

Fig. 23 shows an enlarged view of a detail of the platform frame according to Figs. 20 to 22.

The platform trestle consists in its basic structure of a platform 1, a rectangular upper frame 2 supporting the platform 1, a rectangular lower frame 3 and two X-shaped lifting scissors 4, 5. The scissor legs L 6, 7 of the lifting scissors 4 and the scissor legs 8, 9 of the lifting scissors 5 are fixedly hinged at one end to corner points 10, 11 of the upper frame 2 or the lower frame 3, which are located one above the other, while the other ends 12, 13 can be moved via rollers 14, 15 on slideways 16, 17 of the upper frame or lower frame.

A motor 18 with a self-locking gear 19 is arranged on the lower frame 3, which drives two spindles 21, 22 via a chain drive 20, which are aligned parallel to the long sides of the lower frame 3 and each pass through a spindle nut 23, 24. The spindle nuts 23, 24 are each carried by a carriage 25, 26. Each carriage 25, 26 is supported by a running wheel 27 and one of the rollers 15 on the slideways of the lower frame. The pivot axis 28 carrying the rollers 15 passes through both carriages 25, 26 and forms a common pivot axis for the scissor legs 7, 9. When the motor 18 and the spindles 21, 22 are locked in place on the lower frame, a rotation of the spindles 21, 22 causes the spindle nuts 23, 24 and the carriages 25, 26 carrying them to move to the left in the drawing and thereby raise the scissors, as can be seen in particular from Fig. 3.

In the basic position according to Fig. 1, the scissor legs 8, 9 - or 6, 7 - are almost parallel to each other, and the scissor joint 29 is

at the same height as the central longitudinal axis of the spindles 21 and 22. In this position, the scissor legs do not yet offer a moment arm on which the described spindle drive could effectively engage. To enable starting from the flat basic position according to Fig. 1, the platform trestle is equipped with two auxiliary lifting devices 30, 31. The motor 18 is mounted on a carriage 32 together with its gear 19, the chain drive 20 and the spindles 21, 22. The carriage 32 is supported by four wheels 33, 34, 35, 36 on guide plates 37, 38 of the subframe 3. The guide plates 37, 38 have guide pieces 39, 40 on their inner longitudinal edges, which are provided with guide grooves 41, 42 in which a base plate 43 of the slide 32 is guided exactly parallel to the lower frame 3. The slide 32 can be moved in the direction of the spindle nuts 23, 24 until it hits the stops 44, 45. On each side, the slide 32 also has a run-on roller 46, 47, to which run-on ramps 48, 49 attached to the scissor legs 7 and 9 are assigned. The ramps 48, 49 are each inclined at an angle a of approximately 30 with respect to the longitudinal extension of the scissor legs 7, 9.

In the basic position according to Fig. 1, the running rollers 46, 47 rest on the upper end of the run-up ramps 48, 49, which slope down to the side of the spindle nuts 23, 24. The run-up ramps 48, 49 are located - seen from the spindle nuts 23, 24 - beyond the scissor joint 29.

When the motor 18 is switched on in the position shown in Fig. 1, the spindles 21, 22 rotate into the spindle nuts 23, 24, which act as abutments, so that the entire carriage 32 moves to the right, with the lifting rollers 46, 47 moving under the lifting ramps 48, 49 and raising the scissor legs 7, 9 by an initial distance to the intermediate position shown in Fig. 2. As soon as the carriage 32 has reached the stops 44, 45, the auxiliary lifting devices 30, 31 lose their lifting function. From this point on, the slide assembly forms the fixed abutment, onto which the spindle nuts 23, 24 and thus the movable ends 12, 12 of the scissor legs 7, 9 are now pulled when the spindles 21, 22 are rotated further, so that the further lifting of the platform frame takes place in the usual way by moving the spindle nuts.

The invention is not limited to the embodiment shown. For example, instead of two spindles 21, 22, a single central spindle can be provided, with the two carriages 25, 26 being combined into one carriage.

The motor and the associated Hi Ifs lifting devices can be attached to the upper frame instead of the lower frame. With such a modification, the platform trestle shown in Fig. 1 to 4 would be upside down and only the platform would have to be moved from one frame to the other frame.

Longer platform trestles can also be provided with one of the pairs of scissors shown with associated lifting devices at both ends. In this embodiment, instead of X-shaped scissors, Y-shaped scissors can also be used, in which the movable end 13 of the scissor legs 6, 8, which are not directly driven by the lifting device, can be omitted. In this modified embodiment, the carriage and the auxiliary lifting devices are arranged between the spread scissor leg halves of the Y-scissors.

Figures 5 to 11 show a second embodiment in which the spindle drive 50, which comprises the motor 18, the gear 19, the chain drive 20 and the spindles 21, 22 with their bearings, is supported in a stationary manner on the lower frame 3. An auxiliary lifting device 51, 52 is arranged on each spindle 21, 22. Each auxiliary lifting device comprises a carriage 53 which can be moved on a running surface of the lower frame 3 and a spindle nut 54 which has a flange as a driver 55 which is rigidly connected to the carriage 53. The auxiliary lifting devices 51, 52 are each designed as a spreading device and have an inclined ramp 56 on their carriage 53, which interacts with a run-up member 57 designed as a roller, which is attached to the adjacent scissor leg 7 or 9, see also the enlarged illustration in Fig. 8. The auxiliary lifting devices 51, 52 are arranged in the area of the platform center below the platform 1.

A transmission member 58, which is approximately U-shaped in plan view, is hinged to the movable ends 12, 12 of the scissor legs 7, 9, whereby the linkage is made on the axles carrying the rollers 15. The transmission member 58 can be moved on the floor or on the running surfaces of the lower frame 3 by means of rollers 59. The spindles 21, 22 pass through holes 60 provided in the U-back of the transmission member 58 with play and extend into spindle bearings 61, 61 fixed to the frame. Between the bearings 61 and the U-back of the transmission member 58, a further spindle nut 62 is arranged on each spindle 21, 22, which has a flange-shaped driver 63 on its end facing the bearings 61. The spindle nut 62 can pass through the hole 60 in the transmission member 58 until its driver 63 hits the back of the transmission member 58. In the basic position of the platform block shown in Fig. 5, the driver 63 engages behind the transmission member 58 with a clearance S.

Fig. 7 illustrates the rotational locking of the spindle nut 62, which encloses a base-side slide rail 65 with a fork-shaped projection 64 and is therefore only movable along this slide rail.

When the motor 18 is switched on in the lowest platform position according to Fig. 5 and 9, both spindle nuts 54 and 62 run synchronously to the left, i.e. in the direction of the fixed corner points 11, 11 of the lifting scissor legs. Since the spindle nuts 54, 54 immediately carry the carriages 53, 53 rigidly attached to them, the ramps 56, 56 located on the carriages 53, 53 are moved under the lifting links.

57, 57, which are increasingly raised according to the rise of the ramps 56, 56 up to the intermediate height shown in Fig. 10. During this initial stroke exerted by the auxiliary lifting devices 51, 52, the initially idle spindle nuts 62, 62 reach the operative position shown in Fig. 10, in which their drivers 63, 63 have hit the transmission member 58. When the spindle nuts 62, 62 are advanced further, the drivers 63, 63 take the transmission link 58 with them and are thus now in active engagement with the movable lifting scissor legs 12, 12, so that the platform frame is further raised via the spindle nuts 62, 62 or their drivers 63, 63. The lifting links 57, 57 separate from the ramps 56, 56 and rise with the lifting scissors 4, 5 as shown in Fig. 11. The auxiliary lifting devices 51, 52 therefore run idle in this main lifting phase. During the initial stroke, the auxiliary lifting devices 51, 52 are supported by the rollers of their carriages 53 on the running surfaces of the subframe 3, which act as abutment surfaces 66.

Fig. 12 illustrates a possible modification of the previously described embodiment, which consists in that each ramp 56a is arranged on the ascending scissor leg 9 or 7 and the roller-shaped ramp member 57a is arranged on the carriage 53.

Fig. 13 illustrates a possible modification, which consists in the fact that the drivers 55 and 63 are attached to the ends of a common carrier 67, which here is designed as a

and the transmission member 58 passing through a tube. The tubular support 67 is rigid with a S &rgr;inde I nut arranged inside it

68, which, when the motor 18 is switched on, moves the drivers 55, 63 in the manner described with reference to the embodiment according to Figs. 9 to 11.

Fig. 14 to 19 show a schematic representation of another embodiment in which the only difference compared to the embodiments according to Fig. 5 to 13 is that the auxiliary lifting device - instead of a ramp/running member spreading device - has a spreading lever 69 which is permanently hinged to the scissor joint 29 and has a roller 70 at its other end. In the basic position according to Fig. 14, the roller 70 rests on the bearing surface 66, and the axis of the roller 70 is lower than the scissor joint 29, so that the spreading lever 69 is inclined downwards towards the driver 55.

When the spindle drive is switched on, the driver 55 immediately presses the spreading lever via the roller 70

69 into an increasingly steeper position according to Fig. 15 and 16. During this initial stroke, the second driver 63 initially runs idle. When the second driver 63 has hit the transmission element 58, see Fig. 16, the second driver 63 takes over the further erection of the platform block, whereby the spreading lever 69 separates from the first driver 55 and rises with the platform block. The spreading lever 69 is thereby held in the approximately half-height platform block position according to Fig. 18 by a chain 71 attached to the scissor leg 9 in a

The roller 70 is held in a position inclined towards the driver 55, so that when the platform is lowered from the position according to Fig. 18, the roller 70 is again located in a suitable manner to the right of the upper articulation point of the spreading lever 69 on the scissor joint 29 and the spreading lever 69 can automatically return to the position according to Fig. 1.

Fig. 20 to 22 show a schematic representation of a further embodiment in which, instead of the rod-shaped spreading lever 69 according to the embodiment according to Fig. 14 to 19, an eccentric disk 72 is provided which, in the basic position, has a bearing mouth 73 at one end which loosely accommodates a bolt 74 arranged coaxially to the scissor joint 29. Compare also the enlarged representation according to Fig. 23, which shows the eccentric disk 72 in an intermediate position which lies between the positions according to Fig. 20 and 21. At its opposite end, the eccentric disk 72 is permanently articulated on the driver 55, whereby even in the basic position according to Fig. 20 the articulation point 75 on the driver 55 lies lower than the center axis of the bolt 74. The eccentric disk 72 has on its edge a series of small support rollers 76 which roll one after the other on the bearing surface 66 when the eccentric disk 72 is pivoted. After the initial stroke has been carried out by means of the driver 55, the eccentric disk 72 remains on the driver 55 while the bolt 74 rises together with the shears.

Reference symbolli

1 Platform 31

2 Upper frame 32 3 Lower frame 33

4 Scissor lift 34

5 Scissor lift 35

6 Scissors legs 36

7 Scissors leg L 37

8 Scissor legs 38

9 Scissor legs 39

10 Corner point 40

11 Corner point 41

12 movable ends 42 of 7 and 9 43

13 movable ends 44 of 6 and 8 45

14 Roll 46

15 RoI Ie 47

16 Slideways 48

17 Slideways 49

18 Engine 50

19 Gearbox 51

20 Chain drive 52

21 spindle 53

22 spindle 54

23 Spindle nut 55

24 Spindle nut 56

25 cars 57

26 cars 58

27 Wheel 59

28 Articulation axis 60

29 Scissor joint 61

30 Hi Ifs lifting device 62

Hi Ifs lifting device carriage Wheel

wheel

wheel

wheel

Guide plate Guide plate Guide piece Guide piece Guide groove Guide groove Base plate Stop

attack

Overrun roller Overrun roller Overrun ramp Up I on ramp Spindle drive Hi Ifs lifting device Hi Ifs lifting device Carriage

Spindle nut driver ramp

Overrun link transmission link rollers

Hole

camp

Spindle nut

63 Driver

64 Approach

65 slide rails

66 Counter bearing area

67 carriers

68 Spindle nut

69 Spre i zhebeI

70 roll (lower end of 69)

71 Chain

72 Eccentric disc

73 Bearing mouth

74 bolts

75 Articulation point

76 Support roller

a angle

S Game 56a Ramp 57a On I glide

Claims (10)

Protection claims Height-adjustable platform trestle for the construction of theater stages, stands or the like, with a platform (1) supported by two X-shaped lifting scissors (4, 5) and with a motor spindle drive (50) which engages the scissor legs (6, 7, 8, 9) of the lifting scissors (4, 5) in order to raise them from a flat basic position into a steep extended position, the movable scissor leg ends (12) being mounted on rollers (14, 15), characterized in that a) that in the area of the platform centre below the platform (1) there is a Hi Ifs lifting device (51, 52) which can also be driven by the motor spindle drive (50), b) that when the motor (18) is switched on in the flat base position of the platform, the spindle drive (50) initially only operates the lifting device (51, 52) which raises the platform by an initial stroke, whereby during this initial phase the action of the spindle drive (50) on the lower legs (12, 12) is idle, c) that only towards the end of the initial phase does the spindle drive (50) act on the scissor legs (12, 12) and further raise the platform trestle, during which time the auxiliary lifting device (51, 52) runs idle, d) that the motor (18) drives two parallel horizontal spindles (21, 22) each running next to the X-shaped scissors (4, 5), e) that the X-shaped scissors (4, 5) are each firmly hinged to the corners (10, 11) of the platform trestle on one transverse side and that the opposite movable scissor leg ends (12, 13) in the flat platform trestle base position extend to the corners of the other transverse side of the platform trestle, f) that a cross-beam (28, 58) is mounted on the axes of the rollers (15) of the lower, movable scissor leg slats (12), on which the spindle drive (50) acts after its idle run in order to pull these scissor leg slats (12) directly in the direction of the fixedly hinged lower scissor leg slats (11), g) that the auxiliary lifting device (30, 31; 51, 52) consists of running ramps (48, 49; 56, 56a) and associated running links (46, 47; 57, 57a) and h) that either a run-up ramp (56a) is arranged near the scissor joint on a scissor leg and the associated run-up link (57a) is attached to the spindle drive or that the run-up links (46, 47, 57) are each arranged near the scissor joint on one of the scissor legs and the associated run-up ramp (48, 49, 56) is attached to the spindle drive. 2. Platform trestle according to claim 1, characterized in that the motor (18) is rigidly attached to the subframe (3). 3. Platform trestle according to claims 1 and 2, characterized in that the spindle drive (50) Spindle (21, 22) drives two synchronously running drivers (55, 55; 63, 63) that can be moved parallel to its spindles (21, 22), of which a first driver (55, 55) is in operative connection with the Hi Ifs lifting device (51, 52) in the basic position of the platform trestle and the second driver (63, 63) engages behind the cross-beam (58) hinged to the movable scissor leg (12, 12) with such play (S) that the second driver (63, 63) only comes into operative connection with the cross-beam (58) after the Hi Ifs lifting device (51, 52) has been actuated. 4. Platform trestle according to claim 3, characterized in that the two drivers (55, 63) are attached to a common, tubular support (67) which is rigidly attached to a spindle nut (68) running on a spindle (21, 22) of the spindle drive (50) (Fig. 13). 5. Platform trestle according to claim 4, characterized in that each driver (55, 63) is fastened to an associated spindle nut (54, 62) running on a spindle (21) of the spindle drive (50) (Fig. 5). 6. Platform trestle according to claim 1, characterized in that the motor (18) is mounted on a carriage (32) so as to be movable until it hits a stop (44, 45) limiting the initial stroke. 7. Platform trestle according to claim 1, characterized in that each ramp (48, 49) is inclined by approximately 30° relative to the longitudinal extension of its scissor leg (7 or 9). 8. Platform trestle according to claim 6, characterized in that the carriage (32) has a base plate (43) which is guided on opposite sides in guide grooves (41, 42) of guide pieces (39, 40) fastened to the lower frame (3). 9. Platform trestle according to one or more of claims to 8, characterized in that the brake motor (18) has a gear (19) and the spindles (21, 22) have a self-locking trapezoidal thread. 10. Platform trestle according to one or more of claims 1 to 8, characterized in that the motor (18) is a stepper motor or three-phase motor.