EP0034221A1 - Vertically adjustable platform-trestle for theatre stages or the like - Google Patents

Abstract

1. A vertically adjustable platform-trestle for theatre stages or the like comprising a platform (1) carried by a top frame (2), arrestable supporting scissors (4) articulated to the corners of the top frame (2) and a means for vertical adjustment having a manually actuated or motor operated screw spindle drive characterized in that the movable upper ends of the supporting scissors (4) are provided with detent pins (11) which can be pulled out of retaining holes (12) of the lateral spars (10) of the top frame (2), in that the detent pins (11) can be temporarily arrested even in an unlocked position of the platformtrestle, and in that the means for vertical adjustment is additionally provided with lifting scissors (14, 15) arranged below the platform (1) which - alternating with the supporting scissors (4) - uphold the platform (1) only during the vertical adjustment operation.

Description

The invention relates to a height-adjustable pedestal for theater stages or the like., With a platform carried by an upper frame, with hinged support scissors hinged to the corners of the upper frame and with a height adjustment device that can be driven by motor or physical force.

From DE-GM 73 32 414 an infinitely height-adjustable pedestal of the aforementioned type is known, in which the upper, slidably mounted legs of the support scissors are articulated on spindle nuts guided in the upper frame construction and secured against rotation, which are displaceable by two parallel threaded spindles. The pitch of the thread of the threaded spindles is of such a size that a self There is an inhibition by which the pedestal is locked at the set height. With such pedestals - especially when using a motorized spindle drive - the height can theoretically be adjusted by just one person, however, all moving parts must be manufactured with high precision and all rods and struts with high torsional rigidity in order to prevent canting or jamming caused by the otherwise there may even be bending of the rods. This technical effort makes the pedestal frame relatively expensive and, in general, so heavy that it can only be transported with difficulty when converting a stage floor. In addition, the well-known pedestal requires a considerable spread of its support scissors even in the folded position in order to be able to be raised by the spindle drive. This results in a considerable stack height for the individual pedestal.

The invention has for its object to provide a pedestal height adjustable by a drive, in which the height adjustment is smooth and the stack height is very low.

To achieve this object, it is provided according to the invention that the height adjustment device has one or two additional lifting scissors arranged centrally under the platform, which are provided at their leg ends with rollers or sliders and can be extended against the underside of the platform.

The use of one or two separate lifting scissors in addition to the support scissors arranged at the corners once has the advantage that the support scissors can now be lowered to a flat dead center position in the lowest position, in which the remaining height (stacking height) of the pedestal only from that Stability reasons prescribed thickness of the platform and the cross-sections of the upper frame and the support leg depends. Even when the pedestal is folded to a minimum, there is still a cavity under the platform between the folded-up support shank legs, in which lift shear legs can be accommodated with sufficient stability and with a certain minimum spread, from which the lift shears can be erected by a drive device. It proves to be very advantageous here that the support scissors unlocked when the height is adjusted only run loosely, and so much play can be provided that the scissors do not tilt at all or jams may occur. With a height adjustment, the lifting scissors only have to lift the weight of the platform and sometimes the weight of the support scissors and can therefore be designed with relatively thin cross-sections. After a height adjustment, the support legs are locked again on the pedestal and then, after lowering the lifting scissors, they in turn absorb all loading forces again. This complete separation of supporting scissors and lifting scissors also proves to be particularly advantageous in that the lifting scissors height adjustment device can be manufactured as a separate assembly and can also be retrofitted to pedestals with supporting scissors.

According to a preferred embodiment of the invention, the height adjustment device can consist of two X-shaped lifting scissors arranged next to one another, the lower or upper ends of which are connected in pairs by transverse axes which can be moved relative to one another by a screw spindle drive. Such an embodiment of the height adjustment device is characterized by a symmetrical, force-balanced support of the platform during the height adjustment and can be produced at relatively low costs.

According to a further feature of the invention it can be provided that the lifting scissors rest in their lowest position on compressed lifting springs. These lifting springs, which can carry, for example, 90% of the weight of the pedestal part to be moved up, make it considerably easier to move the lifting scissors out of their lowest position for the first time.

According to the invention, guide rails for the rollers or sliders of the lifting scissors are expediently attached to the underside of the platform and to the pedestal frame at the bottom. The smooth running of the height adjustment device can be improved even further by means of these guide rails.

Pedestals of the Xrt discussed here, which generally have a rectangular plan area of 1 x 2 m, are usually set up in several lifts and one behind the other and then set to the same or to different heights. For example, in order not to have to adjust all of the pedestal stands individually in order to set up a tiered orchestral stage, it is desirable if the pedestal stands and their height adjustment devices are designed in such a way that they can also be adjusted in groups or rows at the same time. For this purpose, according to the invention it is provided that the pedestal stands together with similar pedestals in the longitudinal direction can be arranged in rows and that the screw spindle extends over the length of the pedestal and can be connected to adjacent screw spindles in a rotationally fixed manner by coupling pieces.

Since the pedestals have to be reliably mechanically locked in the respective height setting for safety reasons, the invention is furthermore based on the object of providing the pedestals with a central locking system which enables a row height adjustment of the pedestals by, for example, only one person. According to the invention, it is therefore provided in pedestal trestles in which the movable upper ends of the supporting scissors carry spring-loaded locking pins which can be pulled out of locking openings of the side rails of the upper frame by means of an adjustment device against the spring force that the locking pins are temporarily lockable even in the unlocked position of the pedestal frame are. For this purpose, the locking pins are preferably connected to a central pull rod via Bowden cables, which can be adjusted by an assigned pawl hand lever or by a motorized adjustment drive. According to further features of the invention, the tie rods of lined pedestals can be coupled to one another and the side rails of the upper frame are provided with elongated holes for receiving the locking pins. These measures make it possible to adjust the height first the support scissors from z. B. unlock five row of pedestals in a row, then make the height adjustment with the lifting scissors and subsequently lock the support scissors in the new height setting, which can be done by only one person, who can now operate the locking device and the height adjustment device one after the other.

A further embodiment of the invention is based on the object of improving the balance of forces when starting the upward movement of the scissors from their lowest position. For this purpose, it is provided that the middle joint in each lifting shear lies above the connecting line between the force application point at the foot end and the force output point at the upper end of each lifting shear leg. When the scissors are at the lowest position, the middle joint and the platform-side power delivery points of the scissors are preferably in approximately the same horizontal plane.

These measures result in a considerable increase in the effective torque arm when the lifting scissors are in the lowest position, with the result that only 5 much lower forces than previously are required to raise the pedestals and that the lifting scissors are now used can be built lighter and cheaper. These advantages are apparent in particular when a plurality of successive rows pedestal blocks via a single _such drive strength to be adjustable up and down simultaneously.

According to a further feature of the invention, it can be provided that each lifting shank leg is designed as an elongated rhombus and that the central joint lies in the upper, central rhombus corner.

Finally, according to the invention, in the case of a pedestal in which the height adjustment device consists of two lifting scissors arranged side by side, the lower ends of which are articulated on cross struts which can be moved against one another by a screw spindle, the articulation point of the lifting scissors on the lower cross struts and the screw spindle lie in a common plane. This measure achieves a favorable torque arm in the lowest position in the lifting scissors with high stability of the lifting scissors at the same time.

• Figur 1 einen höhenverstellbaren Podestbock nach der Erfindung, in ausgefahrenem Zustand,
• Fig. 2a den Podestbock nach Fig. 1 in zusammengeklappter Stapelhöhe,
• Fig. 2b in einer Darstellung analog Fig. 2a ein abgewandeltes Ausführungsbeispiel,
• Fig. 3 in einer Ansicht auf die Unterseite die Plattformen zweier aneinandergereihter Podestböcke mit Zentralentriegelungseinrichtung,
• Fig. 4 ein Kupplungsddtail gemäß Position IV in Fig. 3,
• Fig. 5 ein Detail gemäß Position V in Fig. 3,
• Fig. 6 einen Sperrklinkenhebel, der bei Position VI an die Zentralverriegelungseinrichtung nach Fig. 3 anzusetzen ist,
• Fig. 7 in Seitenansicht eine Hubschere für eine Podestbockplattform, in ausgefahrener Stellung,
• Fig. 8 die Hubschere nach Fig. 7 in ihrer tiefsten, zusammengeklappten Stellung,
• Fig. 9 in einer perspektivischen Darstellung eine Antriebsspindel für Hubscheren zusammen mit Querstreben für die Kraftübertragung an die unteren Schenkelenden der Hubscheren,
• Fig. 10 in einer schematischen Darstellung eine abgewandelte Ausführungsform einer Hubschere in Seitenansicht und
• Fig. 11 ein weiteres Ausführungsbeispiel einer Hubschere.

The invention is explained in more detail below with reference to the drawing, in which:

• 1 shows a height-adjustable pedestal according to the invention, in the extended state,
• 2a the pedestal according to FIG. 1 in a folded stack height,
• 2b in a representation analogous to FIG. 2a a modified embodiment,
• 3 shows a view of the underside of the platforms of two pedestal frames lined up with a central unlocking device,
• 4 shows a clutch detail according to position IV in FIG. 3,
• 5 shows a detail according to position V in FIG. 3,
• 6 shows a pawl lever which is to be applied to the central locking device according to FIG. 3 at position VI,
• 7 is a side view of a lifting shear for a pedestal platform, in the extended position,
• 8 shows the lifting scissors according to FIG. 7 in its deepest, folded position,
• 9 is a perspective view of a drive spindle for lifting scissors together with cross struts for the power transmission to the lower leg ends of the lifting scissors,
• Fig. 10 is a schematic representation of a modified embodiment of a pair of scissors in side view
• Fig. 11 shows another embodiment of a lifting shear.

The pedestal frame shown in perspective in FIG. 1, leaving out platform 1 (see also FIG. 2), consists of an upper frame 2 supporting platform 1, a lower frame 3 on the bottom, and four Y-shaped support scissors 4, each with one of its scissor legs 5 , 6 are articulated at points 7, 8 lying one above the other on the upper frame 2 and the lower frame 3, the upper movable leg 9 each being displaceably guided along the side rails 10 of the upper frame 2. The movable legs 9 each carry spring-loaded locking pins 11, which automatically snap into slots 12 of the side rails and the pedestal in the Lock the selected height setting securely. The locking pins 11 can be pulled out of the locking holes 12 by Bowden cables 13 in order to prepare for a height adjustment. Such a pedestal is, for example, explained in great detail in DE-PS 23 05 145.

The pedestal is equipped with a separate height adjustment device, which has two X-shaped scissors 14, 15 arranged side by side in the middle under the platform of the pedestal, the leg ends of which are provided with upper rollers 16 and with lower rollers 17, those on the upper frame 2 and on the Platform 1 guide rails 18 and 3 guide rails 19 are assigned to the subframe. The lower rollers 17 of the two scissors 14, 15 are connected to one another in pairs by a transverse axis 20, 21, which carry a pressure piece 22, 23 provided with a threaded bore. The two thrust pieces 22, 23 provided with opposite internal threads are penetrated by a screw spindle 24, the longitudinal halves of which also have opposite threads. The screw spindle is mounted in bearing blocks 25 on the subframe 3 and can be rotated either by a motor 26 or by a ratchet lever 27. By means of the screw spindle 24, the pedestal can be adjusted up and down between the positions according to FIGS. 1 and 2a, with the support scissors 4 unlocked. In order to facilitate starting from the lowest position according to FIG. 2a, the Lifting scissors 14, 15 in the area of their central joint 28 are loaded upwards by compression springs 29 compressed in this basic position, the force of the spring being designed to correspond to 90% of the weight to be lifted by the lifting scissors.

1 and 2, the upper arms of the lifting scissors legs are shorter than the lower arms, in FIG. 2b an embodiment is sketched in which all arms 30 of the lifting scissors are of the same length.

In order to be able to adjust the height of a plurality of pedestals, one behind the other in the longitudinal direction, the pedestals are assigned coupling pieces 31, by means of which the screw 24 of adjacent pedestals can be connected to one another in a rotationally fixed manner.

The central unlocking device illustrated in FIGS. 3 to 6 is provided so that the unlocking (retraction of the locking pins 11) of the pedestals can also be carried out conveniently — and also for a large number of pedestals that are lined up in series. This consists of a pull rod 32 which is displaceably mounted under the platform 1 and which is each connected to a pull rod §2 'by a U-shaped coupling bracket 33 adjacent pedestal bracket 1 'is connectable. In the exemplary embodiment, the tie rods 32, 32 'near their end have a transverse bore through which the U-shaped coupling bracket 33 can be inserted with its two legs. The U-legs are in turn provided with cross holes for receiving locking pins 34. The souls 35 of the Bowden cables 13 are fastened to the pull rod 32. The jackets of the Bowden cables 13 are rigidly attached to the platform 1 close to the pull rod 32 via bearing blocks 36. Each core 35 runs between two guide rollers 37 rigidly fastened to the bearing block 36, passes through a transverse bore in the pull rod 32 and is fastened to its rear side by a transverse head 38. Since the guide rollers 37 are located in the immediate vicinity of the pull rod 32, a force for pulling the support bolts 11 out of the locking holes 12 is always exerted regardless of the direction of displacement of the pull rod 32 via the Bowden cable core 35.

The tool illustrated in FIG. 6, which is designed as a pawl lever 39, can be used to adjust the pull rod 32, in which the force of the load springs of all locking pins 11 must be overcome. The auxiliary tool has a U-shaped base body 40 which is placed with the U opening over the edge of the platform 1. At the opposite end an axis 42 is mounted in vertical cheeks 41 of the base body 40, about which a lever 44, which can be extended by a pipe section 43, is pivotably mounted, which carries at its lower, extended end an articulated tab 45 which is connected via a bracket 33 (see also FIG. 4 ) can be coupled to the end of the pull rod 32. On the axle 42 is also a ratchet wheel 46, which is blocked by a tension spring-loaded pawl 47 against rotation counterclockwise.

To make a height adjustment of a series of connected pedestals are first switched on by z. B. the electric motor 26, the lifting scissors 14, 15 of all pedestals extended until these lifting scissors have raised the platforms somewhat, so that the locking pins 11 are relieved in the central region of the associated elongated holes 12. 6 is then attached to the pull rod 32 and by pushing the pipe 43 in the direction of the arrow 48, all the locking pins 11 are withdrawn from the locking holes 12. The pawl 47 holds the pawl lever 39 and thus the pull rod 32 in this unlocked position. The lifting scissors 14, 15 can now be extended somewhat higher than the desired new end position of the platforms by motor. Then the pawl 47 is released and the pull rod 32 is thus released. The locking pin 11 are now pressed by their springs against the side rails or penetrate into the locking openings 12 with a favorable alignment. Possibly. when unlocking still on the material of the side rails resting pegs 11 snap automatically in the subsequent lowering of the scissors 14, 15 in their associated elongated holes 12, after which the scissors 14, 15 are then completely released from the platform 1, so that the loads on Platform can later only be carried by the support scissors 4.

The invention is of course not limited to the illustrated embodiment. For example, instead of a central spindle 24, two parallel spindles can also be provided for adjusting the lifting scissors 14, 15. Furthermore, instead of unlocking by means of a mechanical auxiliary device according to FIG. 6, an electric or electromagnetic drive can also be provided for the unlocking. Because of a possible incorrect actuation of an unlocking device that can be triggered by pressing a button or a switch, the use of an auxiliary device that can be removed again after carrying out a height adjustment is preferred, since unauthorized or unwanted unlocking is thus excluded.

7 and 8, the platform 1, the upper frame 2 and the foot frame 3 of the pedestal are indicated schematically. For the height adjustment of the pedestal, there are two parallel lifting scissors 49 - only one can be seen in FIGS. 1 and 2 - which are provided in addition to the supporting scissors of the pedestal. The legs 50, 51 of the lifting scissors each have rollers 52, 53, 54, 55 at their ends.

FIG. 9 shows the lower rollers 52, 52 'and 54, 54' of the two lifting scissors one behind the other in FIG. 7. These wheels are mounted together with the lower ends of the lifting shank legs 50, 50 ', 51, 51' by means of axle bolts 56, 56 'in frame-shaped cross struts 57, 58 which are penetrated by the drive screw spindle 24, which has two opposing threaded sections. The two opposing threaded sections of the spindle 24 are each received in threaded pieces 22, 23, which are firmly welded to the longitudinal bars of the cross struts 57, 58. The spindle 24 lies in the same horizontal plane as the axle bolts 56, 56 '.

The central axes of the lower axle bolts 56 represent the points P1, at which the driving force exerted via the spindle is introduced into the scissors 50, 51. In the embodiment of FIGS. 7 and 8, the The central axes of the upper wheel bearing bolts represent the points P2 at which the scissors 50, 51 transmit their force to the wheels 53, 55. As can be seen from FIGS. 7 and 8, in the case of the lifting scissors, the central lifting scissor joint 59 lies above the connecting line V between the force application point P1 and the shaft release point P2 of each lifting scissor leg. This also results in a favorable torque arm for a first start-up of the lifting scissors in the lowest position according to FIG. 8. The scissor legs 50, 51 each have the shape of elongated rhombuses amf, the central joint 59 being arranged near the upper central rhombus corner.

In the exemplary embodiment according to FIG. 10, angled scissor legs 60, 61 are provided which carry sliding pieces 62 at their upper ends for supporting the platform 1. The force delivery points P2 are here at the points of contact of the sliders with the platform 1. Here, too, the central joint 59 'lies above the connecting line V between the force application point P1 and the force delivery point P2.

In the embodiment according to FIG. 11, the scissor legs 63, 64 in turn carry rollers 65, 66 at their upper ends, so that here the upper power delivery points P2 of the scissor legs again coincide with the axes of the wheels 65, 66, the middle pivot point 59 '' of the scissors Leg 63, 64 is here in the lowest scissor position approximately in the same horizontal plane as the force output points P2 and at the same time on the connecting line between the force application point P1 and the contact point P3 of the impeller 66 on the platform 1.

Claims (13)

1. Height-adjustable pedestal for theater stages or the like., With a platform supported by an upper frame, with lockable scissors hinged to the corners of the upper frame x and with a motor-driven height adjustment device driven by physical strength, characterized in that the height adjustment device is centered one or two below the platform (1) arranged additional lifting scissors (14, 15), which are provided at their leg ends with rollers (16, 17) or sliders and can be extended against the underside of the platform. 2. Pedestal frame according to claim 1, characterized in that the height adjustment device consists of two X-shaped, side by side lifting scissors (14, 15), the lower ends of which are connected in pairs by transverse axes (20, 21), which are connected by a screw spindle (24) are movable against each other. 3. Pedestal frame according to claims 1 and 2, characterized in that the lifting scissors (14, 15) rest in their lowest position on compressed lifting springs (29). 4. pedestal according to claims 1 to 3, characterized in that on the underside of the platform (1) and on a bottom pedestal frame (3) guide rails (18, 19) for the rollers (16, 17) or sliders of the lifting scissors ( 14, 15) are attached. 5. Pedestal frame according to claims 1 to 4, characterized in that it can be strung together with the same in the longitudinal direction and that the screw spindle (24) extends in each case over the length of the pedestal frame and can be connected in a rotationally fixed manner by coupling pieces (31) to adjacent screw spindles. : 6. Pedestal frame according to one or more of claims 1 to 5, in which the movable upper ends of the support scissors carry spring-loaded locking pins which can be pulled out from locking openings of the side rails of the upper frame by an adjusting device against the spring force, characterized in that the locking pins (11) can also be temporarily locked in the unlocked position of the pedestal. 7. pedestal according to claim 6, characterized in that the locking pins (11) via Bowden cables (13) are connected to a central pull rod (32) which is adjustable by an associated pawl hand lever (39). 8. pedestal frame according to claims 6 and 7, characterized in that the tie rods (32) lined up pedestal frames can be coupled together. 9. pedestal according to claims 1 to 8, characterized in that the side rails (10) with elongated holes (12) for receiving the locking pin (11) are provided. 10. pedestal according to claims 1 and 2, dadurdh characterized in that the central joint (59) in each lifting shear (49) above the connecting lines (V) between the force application point (P1) at the foot end and the power output point (P2) at the top of a each lifting shear leg (50, 51). 11. Pedestal frame according to claim 10, characterized in that at the deepest lifting scissor position, the central joint (59 ") and the platform-side power delivery points (P2) of the lifting scissor legs (63, 64) lie in approximately the same horizontal plane. 12. Pedestal frame according to claims 10 and 11, characterized in that each lifting shank leg (50, 51) is designed as an elongated rhombus and that the central joint (59) lies in the upper, central rhombus corner. 13. Pedestal frame according to one or more of claims 10 to 12, in which the height adjustment device consists of two lifting scissors arranged side by side, the lower ends of which are articulated to cross struts which can be moved relative to one another by a screw spindle, characterized in that the articulation points (P1) Lifting shank legs (50, 51) on the lower cross struts (57, 58) and the screw spindle (24) lie in a common plane.

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