EP1819627B1 - Hoist device - Google Patents

Abstract

The invention relates to a hoist device, in particular, for the automobile industry, comprising an upper frame (1) and a lower frame (2), arranged below the above, whereby the lower frame (2) is held on the upper frame (1) by means of at least three essentially vertically-running ties (3) and at least four tensioning means (4), at an angle to the vertical, such as to be vertically displaced by means of powering the ties (3) and the tensioning means (4). Pairs of tensioning means (4) at least approximately engage at a common point (5) on the lower frame (2). According to the invention, the pivoting may be simplified and improved, whereby the ends of the two tensioning means (4) pass over a joint (14) connected to the lower frame (2), permitting the rotation of the lower frame (2) relative to the tensioning means (4) about a rotational axis (15), given by both engagement points (5) of the tensioning cables (4) on the lower frame (2).

Description

The invention relates to a lifting device, in particular for the automotive industry, with a top frame and a lower frame arranged thereunder according to the preamble of claim 1 and EP 123 846 A ,

This document shows, as well as the DE 32 41 380 A , the US 3,653,518 A and the US 5,769,250 A Such a lifting device, but not on the automotive industry, but the loading of containers is parked. Therefore, while value is placed on a stable movement, if possible without oscillation of the load, the question of the safety of the person under the load does not arise, nor does the desired pivoting of the load about at least one horizontal axis, such as during painting, etc. often desired.

Lifting devices are used to lift and transport heavy loads, especially car bodies in the automotive industry, and must therefore withstand high loads. On rails coming down from the ceiling of production halls such lifting devices are movably mounted and transport the vehicle body to be manufactured from one work step to the next. In most cases, the load lifting device and the load hover over the heads of many workers who weld, assemble, cabling, etc. at the bottom of the body.

A load lifting device is for example from the EP 1 106 563 B1 known. It consists of a top frame, a subframe and provided therebetween, connected to a drive traction cables. The traction cables are guided over pulleys on a motor-driven drum. In addition to fully vertical ropes, ropes are also provided, which extend partially obliquely to the vertical. Such a cable extends from the upper frame obliquely to the sub-frame, where it is steered around a roller and then extends vertically in the direction of the upper frame, where it is then connected to the same drive, which is also intended for the vertical cables. The partially inclined ropes serve to increase the stability of the sub-frame and the load hanging thereon. In order to prevent the load held by the load lifting device from falling due to a cable break and crushing a person working thereunder, a double vertical cable guide is proposed. Although additional ropes, pulleys and suspensions can prevent a crash, at the same time, however, the weight of the lifting device and thus also the manufacturing, assembly and maintenance costs increases.

The DE 23 19 647 discloses a crane for lifting loads. In this case, a loading member, on which the loads to be transported are attached, hangs on lifting ropes whose suspension points are in the carriage of the crane. In addition to the hoisting ropes auxiliary cables are provided which are guided to a separate cable drum and which extend obliquely both to the longitudinal direction and to the transverse direction of the loading member. The loader itself is rectangular and all ropes, ie both auxiliary and hoisting ropes, engage in the corner areas of the loader. This design is designed to allow accurate load placement without causing larger pendulum motion. A pivoting of the load about a horizontal axis is not provided and with such a device also difficult and limited possible. All ropes or rope lengths would have to be coordinated in such a maneuver in a strictly defined manner to each other.

The US 4,705,180 discloses a lifting device consisting of vertically arranged pull ropes and in addition to four auxiliary ropes extending substantially along the edges of a pyramid to the loading platform. As in the previous publication, all ropes in the corner areas of the loading platform also attack here. A pivoting about a horizontal axis is not intended with such a device and also not possible, since all four traction cables are wound on the same cable drum.

The US 5,769,250 (or the corresponding EP 0 793 615 B1 ) discloses a lifting device in which a loading platform can be raised or lowered by means of cables. All ropes acting in this device are aligned obliquely to the horizontal, wherein in each case a traction means, consisting of a roller attached to the loading platform and a revolving rope, engages in a corner region of the loading platform. In the area of the shorter sides of the loading platform are located between the arranged in each corner pulleys two more pulleys, run around the additional auxiliary ropes. The device disclosed in this document is based on the use of four identical but mechanically independent control mechanisms, which are tuned to a travel information of each auxiliary cable and the respective rotational speed of the motor connected to the auxiliary cable or the drum. It can be damped by such a device occurring in a horizontal plane vibrations, however, a pivoting of the position platform to a horizontal axis is not possible and not intended.

• eine hohe Stabilität des Unterrahmens samt dem darauf befestigten Gehänge für die Aufnahme von Fahrzeugkarossen, gegen darauf wirkende Kräfte, beispielsweise verursacht durch Beschleunigung bzw. Verzögerung beim Verfahren zum nächsten Arbeitsschritt, menschliche Muskelkraft, Kräfte und Vibrationen durch Werkzeuge oder andere Anlagenteile (Manipulatoren),
• eine geringe Bauhöhe im eingefahrenen Zustand bei gleichzeitig großer Hubhöhe,
• eine hohe Sicherheit gegen das Abstürzen der Last, da in den meisten Arbeitsschritten Menschen neben oder unter der Lasthebevorrichtung bzw. der von ihr gehaltenen Last arbeiten,
• ein möglichst kleines Eigengewicht bei großen bewegten Massen,
• günstige Fertigungs-, Montage- und Wartungskosten der Lasthebevorrichtung,
• eine möglichst lineare Hubgeschwindigkeit, wodurch auch geringere Leistung aufweisende und daher kostengünstigere Motoren eingesetzt werden können,
• eine Hubbewegung möglichst in vertikaler Richtung,
• Zusatzvorteile für den Anwender, z.B. Möglichkeit einer Drehbewegung des unteren Aufnahmegestells um eine der beiden horizontalen Raumachsen.

Lifting equipment has to meet a lot of requirements in order to be efficient on the one hand and on the other hand to comply with the statutory safety precautions to be able to carry. In addition, the production of such lifting devices should be connected inexpensively and without much effort. The following properties must be fulfilled:

• a high stability of the subframe together with the hanger fastened thereon for receiving vehicle bodies, against forces acting on them, for example caused by acceleration or deceleration in the process to the next work step, human muscle power, forces and vibrations by tools or other equipment parts (manipulators),
• a low overall height in the retracted state with simultaneous high lift height,
• a high degree of safety against the falling of the load, since in most work steps people are working next to or under the load lifting device or the load it holds,
• the smallest possible weight for large moving masses,
• favorable manufacturing, assembly and maintenance costs of the lifting device,
• as linear as possible a stroke speed, which can also be used lower-power and therefore cheaper engines,
• a lifting movement in the vertical direction, if possible,
• Additional benefits for the user, eg possibility of a rotary movement of the lower support frame around one of the two horizontal spatial axes.

The efforts for more safety are becoming increasingly important. Instead of additional safety ropes mechanical safety devices, similar to those in elevator construction, or completely redundant systems are often used. However, mechanical safety gears are not always reliable for loads of a few tons and for redundant systems the same elements are only used in duplicate. Due to signs of wear, which affect both element systems in the same way, however, the likelihood is high that in case of failure of a system and the second can no longer perform its function reliably, so that the risk of a crash can hardly be reduced.

There is a need for a Schwerlastgehänge especially for the final automotive assembly, which offer a market advantage over already known Hubgehängen by its low height in retracted state, its low weight and its low price. This advantage should be further increased by that at Need pivoting of the sub-frame about a horizontal axis, for example, the longitudinal axis of an automobile (at least up to an angle of 60 °) is possible. In the vehicle final assembly, pivoting about the longitudinal axis of the vehicle and pivoting across the vehicle longitudinal axis are most often important in the vehicle finish.

The present invention has the object to achieve these objectives and to avoid the problems known from the prior art, and to propose a load lifting device which ensures a high stability of the lower frame including receiving frame against forces acting on it, has a low dead weight and thereby at the same time provides the best possible safety for the people working on the lifting device, and which can be pivoted about a horizontal axis. With such a device large pivoting angle should be feasible and complicated control and regulating mechanisms are bypassed by a simple basic design. In particular, the slackening of traction means should be prevented.

According to the invention these objects are achieved with a load lifting device of the type mentioned by the measures indicated in the characterizing part of claim 1,

By this measure it is achieved that a pivoting of the subframe is made possible without the length of individual bracing cables must be changed. This significantly simplifies the pivoting, while all the benefits inherent in the oblique bracing cables can be fully utilized. The term "at least approximately" means that slight deviations from a common point of attack are permissible as long as the bracing cables do not become slack during pivoting. In the case of minor deviations from a point of application, the inherent elasticity or the resulting change in length of the tensioning cables must at least compensate for the changes in position of the cable ends with respect to the cable direction.

In a variant of the invention, the drive of the traction means is hydraulically coupled to a pressure accumulator. This can be achieved effectively shock and collision shocks.

In one embodiment, the drive for the traction cables and the drive for the bracing cables are hydraulically connected to each other with respect to the power supply via a pressure accumulator. Although they are mechanically decoupled with respect to the rotation, but can be powered by the same energy source.

In a further embodiment, the drive for the traction cables and the drive for the tensioning cables are completely separated from each other.

By the mechanical decoupling of the two drives two independent systems are created, wherein the traction means consisting of vertical traction means for raising and lowering of the load is used, while the system consisting of the oblique Verspannmitteln ensures sufficient stability of the subframe, together with the hanging load. As soon as a partial or complete failure of the traction system occurs due to wear, the system consisting of inclined bracing means, ie the inclined ropes, can absorb the load, whereby a drop of the load can be efficiently prevented. Although only a separate drum with an associated drive, e.g. Electric motor is required, this system will meet the same and in many cases even higher safety standards as lifting devices from the prior art, which have complicated or redundant security systems.

With a complete separation of the drives, a first motor is used to drive the vertical ropes, while the second motor is used to unwind the inclined ropes or bracing cables. In contrast to the first motor, this drive does not have a constant gear ratio between the lifting movement and the rotary drive. However, since only small forces are to be transmitted in normal operation, this is not a problem. In contrast, the ratio of the first motor is constant, resulting in the lowest possible drive power. To control the second drive, so That for the bracing cables, either a 2-axis control can be used, or it can be a corresponding readjustment, by detecting a relative displacement of two, for example via a preloaded spring coupled elements to each other, for example by inductive data acquisition, holding the tension cables at a constant voltage. If the lifting motor fails, the second motor can now hold the load. Required are only correspondingly claimable traction means, a reliable transmission and appropriately designed brakes. It is not necessary that the second motor can lift the load.

In a particularly preferred embodiment of the invention, the load lifting device is characterized in that for tilting the subframe at least one vertical traction means has a drive independent of the other vertical traction means. This means that the vertical traction system has two or more motors, so that e.g. two traction means are wound by a single motor, while the rest are driven by another motor. In principle, it is possible that all traction means have their own engine, which allows tilting in all directions. The pivoting or tilting of the subframe is similar to playing with a string puppet figure.

In a further embodiment, at least one biasing means running obliquely to the vertical has a drive independent of the other biasing means extending obliquely to the vertical. If the load is tilted by a plurality of independently controllable drives in the traction system, the required tension in all bracing means can be maintained by this measure without one of the bracing means becoming slack.

In a preferred variant, the system is determined kinematically consisting of upper frame, subframe, traction means and Verspannmittel, preferably kinematically overdetermined. This ensures stability with respect to forces acting horizontally on the subframe and rotation about the vertical.

In a particularly preferred variant, the tensioning means engage the subframe at two points, wherein the connecting line between the two points of attack in essentially by the vertical projection of the center of gravity of the subframe in the points of attack comprehensive horizontal plane goes.

In one embodiment, the bracing means engage the subframe at at least three points, the outer contour of the at least three points of attack enclosing the vertical projection of the center of gravity of the subframe into the horizontal plane comprising the points of application.

In another embodiment, the contour of the biasing means projected vertically into the horizontal plane of the center of gravity of the subframe encloses the center of gravity of the subframe.

By these measures it is achieved that the load can not pivot heavily in case of failure of the traction system, but remains substantially in the original position.

• Fig. 1 eine Lasthebevorrichtung von der Seite mit zwischen vertikalen Seilen angeordneten Verspannseilen,
• Fig. 2 dieselbe Lasthebevorrichtung um 90° gedreht,
• Fig. 3 die Lasthebevorrichtung in dreidimensionaler Darstellung,
• Fig. 4 eine Lasthebevorrichtung mit verkipptem Unterrahmen von der Seite,
• Fig. 5 die Lasthebevorrichtung aus Fig. 5 um 90° gedreht,
• Fig. 6 die Lasthebevorrichtung aus Fig. 5 in dreidimensionaler Darstellung,
• Fig. 7 eine Detaildarstellung einer Lasthebevorrichtung von der Seite,
• Fig. 8 die Lasthebevorrichtung aus Fig. 7 um 90° gedreht,
• Fig. 9 die Lasthebevorrichtung aus Fig. 7 in dreidimensionaler Darstellung,
• Fig. 10 eine Lasthebevorrichtung mit vier Motoren,
• Fig. 11 die Lasthebevorrichtung aus Fig. 10 um 90° gedreht,
• Fig. 12 eine Lasthebevorrichtung mit vier Motoren in dreidimensionaler Darstellung,
• Fig. 13 bis 16 eine Lasthebevorrichtung im Detail,
• Fig. 17 bis 25 eine Variante der Erfindung,
• Fig. 26 bis 30 eine bevorzugte Ausgestaltung der Erfindung.

In the following the invention will be explained in more detail with reference to the drawing. It shows

• Fig. 1 a load lifting device from the side with tensioning cables arranged between vertical ropes,
• Fig. 2 the same load lifting device rotated by 90 °,
• Fig. 3 the load lifting device in three-dimensional representation,
• Fig. 4 a load lifting device with a tilted subframe from the side,
• Fig. 5 the load lifting device off Fig. 5 turned by 90 degrees,
• Fig. 6 the load lifting device off Fig. 5 in three-dimensional representation,
• Fig. 7 a detailed view of a load lifting device from the side,
• Fig. 8 the load lifting device off Fig. 7 turned by 90 degrees,
• Fig. 9 the load lifting device off Fig. 7 in three-dimensional representation,
• Fig. 10 a load lifting device with four motors,
• Fig. 11 the load lifting device off Fig. 10 turned by 90 degrees,
• Fig. 12 a load lifting device with four motors in three-dimensional representation,
• Fig. 13 to 16 a lifting device in detail,
• Fig. 17 to 25 a variant of the invention,
• FIGS. 26 to 30 a preferred embodiment of the invention.

Fig. 1 . 2 and 3 show schematically from various points of view (without pulleys, drums and motors) a load lifting device with a top frame 1, a lower frame 2 arranged underneath, which is held by ropes 3, 4 on the upper frame 1. The upper frame 1 can, as in Fig. 7 indicated, provided with a movable rail 7 on a corresponding suspension 6 or be attached directly to the ceiling of an assembly hall. The frames 1, 2 are usually quadrangular, but they could also triangular, rounded, circular, oval or take any other form and optionally be provided with braces. You can run as a three-dimensional framework and / or be integrally connected to the receiving frame 8

The cable system consists of a group of substantially vertical ropes 3 and a group of obliquely to the vertical ropes 4. In order to prevent the tilting of the lower frame 2 downwards, so a rotation about a horizontal axis, which consists of vertical ropes 3 group have at least three, attacking at the corners of a triangle ropes. Of course, four or more vertical cables 3 are of course used, on the one hand for safety and stability reasons, on the other hand almost exclusively rectangular, preferably rectangular sub-frames 2 are used. The traction cables 3 preferably engage in the region of the corners or in the region of the outer edges of the frames 1, 2 and are arranged so that all traction cables are loaded with the same load substantially equal. Usually, the center of gravity of the structure carried by the cables, consisting of the support frame 8 for the load and the load 9 itself, is substantially below the center of gravity of the subframe 2.

The obliquely to the vertical ropes 4 are also called bracing cables. They serve to increase the stability of the load lifting device relative to the forces acting on the lower frame 2 and the receiving frame 8 for the load and thus to suppress a rocking or swinging of the lower frame 2 with respect to the upper frame 1. Such forces occur, for example, as a result of accelerations or delays when starting from one workstation to the next, with the inertia of a load weighing several tons coming to bear. Much less impact on people or tools transferred from forces.

With the obliquely oriented to the vertical bracing 4 a displacement of the sub-frame 2 in horizontal directions and a rotation about the vertical axis is suppressed.

The group consisting of obliquely tensioned ropes 4 must also comprise at least three ropes, which act on at least two points 5 on the subframe 2 with sufficient biasing force of the ropes. The three bracing cables 4 must lie in different vertical planes. For example, they can be as in Fig. 3 shown, with just any of the four ropes 4 would be inconceivable. In order to prevent the rotation about the vertical, at least two as far as possible from each other remote attack points 5 must be provided both on the subframe 2 and on the upper frame 1.

The three vertical cables 3 prevent rotation about the horizontal axes and displacements along the vertical, while the three bracing cables 4 suppress displacements along the horizontal directions and rotations about the vertical. Such a system is also referred to as kinematically determined in mechanics.

As with the group of vertical ropes 3, four or more ropes are preferred for the same reasons also in the group of inclined ropes 4. In each case two Verspannseile 4 can lie in the same plane. How out Fig. 3 As can be seen, the tensioning cables 4 form the edges of a tetrahedron. Thus, such a system is kinematically over-determined, but is preferred because of safety considerations. It would also be conceivable, of course, a four-sided pyramid formed by Verspannseile 4, the apex is located on the upper frame, however, would be possible by this arrangement a rotation about the vertical axis and the system therefore underestimated kinematically. In case of failure of the vertical cable system, it could still take the load. A kinematically determined or overdetermined solution would be, for example, that the tensioning cables 4 do not extend to the apex of a pyramid, but attack in advance at four points of attack on the upper frame 2.

In the illustrated embodiment of Fig. 3 the lower frame 2 and the upper frame 1 are quadrangular, the vertically extending ropes 3 attack at the corners and the obliquely to the vertical ropes 4 at opposite side edges of the quadrangle. In each case, a pair of cables is provided for two opposite sides of the quadrilateral, wherein the points 5 of the two Verspannseile 4 of a pair coincide and form the two Verspannseile starting from the common point 5, a V-shaped structure. The belonging to this pair of cables ropes 4 are symmetrical with respect to the vertical plane through the common point 5 and by the on the opposite side of the sub-frame 2 located attack point 5 of the other pair of cables goes. In this case, since the cable lengths of the tensioning cables 4 are the same length, in the event of a defect or total failure of the vertical cable system, the load is evenly distributed over all the tensioning cables 4.

Clamping cables 4 of equal length also represent a preferred embodiment for the following reason: With the same length, all the tensioning cables 4 can be wound up with a single drive. In contrast, at different angles to the vertical and therefore different cable lengths, a separate drive with different rotational speed would have to be provided for each tensioning cable 4 in order to prevent ropes becoming limp when lifted.

In order to prevent the load 9 from being tilted heavily in the event of a breakdown of the vertical cable system, the center of gravity of the structure supported by the cables must also be taken into account. The connecting line between the points 5 on the sub-frame 2 is preferably substantially by the projection of the center of gravity of the sub-frame 2 in the horizontal plane containing the points 5 ( Fig. 3 ) or is located at unevenly distributed load above the expected center of gravity. In the event of failure of the vertical cable system 3, the tensioning cables 4 take over the load without causing a strong pivoting of the receiving device 8 together with the load 9. Since the center of gravity of the load 9 is far below the sub-frame 2, deviations of a few centimeters hardly affect. At several points of attack, it is advantageous if they are distributed substantially uniformly around the center of gravity of the sub-frame 2, the attached support frame 8 or best of the load 9 thereon. Usually, the sub-frame is anyway designed so that its center of gravity is substantially above the expected center of gravity of the load.

In many cases it is also sufficient that the load does not fall on the ground, for example when no people work nearby. The position of the attack points plays a minor role in these cases. However, in order to prevent slippage of the load 9 on the support frame 8, the center of gravity of the subframe 2 should in any case lie within an outline created by the vertical projection of the tensioning cables into the plane of the subframe 2. Or in another variant that the outer outline the attack points 5, the projection of the center of gravity of the sub-frame 2 in the attack points 5 comprehensive horizontal plane encloses.

Another variant (not shown) is the in Fig. 3 shown tetrahedron by 45 ° to rotate through the center of the quadrilateral vertical axis and move the points 5 to the corners of the frame. This gives the bracing even stronger inclination, resulting in better stability. However, it comes at the corners when using pulleys 10 to space problems that can be solved by slight displacement of the points 5.

Of course, more than four guy ropes are possible, e.g. 8, which run along the edges of two interpenetrating tetrahedra. The important thing is that the bracing cables give the system stability and can absorb the entire load if the vertical system fails.

In the following, instead of the terms "vertically extending cables" and "obliquely extending to the vertical bracing cables" the terms "vertically extending traction means" and "obliquely to the vertical bracing means" are used, so that all equivalents include. Like from the Fig. 7 to 12 namely, it can be seen, instead of a single strand of rope, which is rolled up on a drum on the upper frame, also a flaschenzugartiges structure are used, wherein the lower frame mounted rollers 10 are provided. Of course, instead of a simple pulley several turns can be provided. Bands can be used as well as ropes. It is therefore a band or rope-shaped tensile or Verspannmittel. This expression is intended to encompass all these variants below.

The group consisting of Verspannmitteln 4 has a separate from the drive of the vertical traction means 3 drive. The two groups are therefore drivingly decoupled from each other completely. This does not mean that the drive for the Verspannmittel 4 operates independently. He must "go along" and maintain the tension in the tensioning means when lifting and lowering the load.

The drive of the vertical traction means has a constant gear ratio between the lifting movement and the rotation of the drum 11 to be wound up with the traction means.

Because of this linearity, lower power motors can also be used. The drive for winding the oblique biasing means, in contrast, has no constant gear ratio between the lifting movement and the rotation. Since in normal operation but only small forces are to be transmitted - the lifting movement is indeed mainly by the vertical Zugmittelantrieb -, this is not a problem. It is only a control of this drive necessary to the Verspannmittel 4 at any time of the raising or lowering operation in to keep it taut and thus provide stability. For example, a 2-axis control with corresponding sensors can be used to determine the absolute position of the tensioning means. A readjustment can also be due to a displacement of two elements zueinender, for example via a preloaded spring, wherein the displacement can be determined by an inductive system, take place. Depending on the desired voltage of the Verspannmittel 4, the rotational speed of the motor can be readjusted via a control unit. Controls to keep a certain (rope) voltage over the rotational speed of a motor constant, are well known in the art and need no further explanation.

When the vertical traction system fails, the drive of the tensioning system now takes over the load. Required are only correspondingly claimable bracing, a reliable transmission and appropriately designed brakes, so that a crash of the load can be reliably prevented. The engine does not have to be able to lift the load.

The characteristic of separate drives means that two birds are killed at the same time: the stability of a lifting device is increased by the use of bracing cables, while at the same time without significant weight gain - for the realization of this measure, only one additional, compared to the lifting motor, is much smaller dimensioned motor and a drum required - much more safety for the workers and the load to be kept is guaranteed.

A preferred embodiment of the invention will be described below. Fig. 4 . 5 and 6 show a load lifting device with a tilted sub-frame 2. For such a frame, two motors are provided for the vertical traction system, that is that which consists of vertical traction means. In each case, two of the four vertical Traction means operated by separate motors. Similar to a hanging on strings puppet, which can be brought to life by shortening or lengthening individual threads, the sub-frame 2 can be tilted, for example, to allow workers access to hard to access body parts. If like in Fig. 6 illustrated the connecting line of two points 5 simultaneously represents the axis of rotation during tilting, it is sufficient if the Verspannmittelsystem has a single motor. If this is not the case, two or more motors may be provided, as in the Fig. 10 . 11 . 12 shown. By this measure it is achieved that none of the Verspannmittel 4 loses its tension during tilting of the lower frame 1 and becomes limp. In a preferred embodiment, therefore, at least when the upper frame 1 and the lower frame 2 are in a parallel position, all the tensioning means 4 have substantially the same length. In the embodiment of the Fig. 10 . 11 and 12 For example, a tilting of the load about an axis parallel to the direction of travel of the load lifting device, ie the rail 7, possible.

The traction means and Verspannmittel are usually out of the direction of the lower frame 2 coming over pulleys 12 or directly on grooves or guides provided with drums 11. The drums 11 serve to wind up the tension and tensioning means and are operated by motors 13. Pulleys 12, drums 11 and motors 13 are mounted or mounted on the upper frame 1.

The from the 8 to 12 apparent, slightly inclined leadership of the vertical traction means is due to obliquely guided grooves in the drums 11 and thus changes slightly when lifting and lowering the load.

While in the Fig. 1 to 6 the connection of the Verspannmittel 4 to the sub-frame 2 and the loading platform is only schematically outlined, show the Fig. 13 to 15 the detailed embodiment of the opening in a single point 5 on the lower frame 2 clamping means in different views. In the case shown, these are simple ropes, however, as already mentioned above, pulley-type or tensioning and tensioning means consisting of bands can also be used. Fig. 13 shows only a section of the sub-frame 2, but on the opposite side of the sub-frame, the connection of the other two Verspannseile identical, preferably formed mirror-symmetrical.

The two Verspannseile 4 form more or less a pair of pointers, which has the same axis. Under pointer pair are understood in this application, two straight lines that lie substantially in one plane and emanate at least approximately from a single point. It can be clearly seen that the two Verspannseile 4 transition at its end in a joint 14, which allow the rotation of the lower frame 2 with respect to the Verspannseile 4 about an axis 15 through the two opposite points of attack 5 of the two Verspannseile 4 on the subframe is defined. In the illustrated embodiment, this is a universal joint, one axis of which is normal to the axis of rotation 15 and normal to the vertically extending traction means 3 and the second axis is aligned substantially normal to the Verspannmittel 14. The end of the Verspannmittel 4 is attached to brackets 16 which form part of the universal joint and are rotatable about the same axis. Of course, also conceivable hinges, ball joints and the like.

The imaginary extensions of the cables or the straight lines defined by the bracing means 4 intersect each other at a point which lies on the axis of rotation 15. Slight deviations from this requirement are permissible as long as the clamping means remain taut when the subframe is swiveled. In other words, the changes in position of the ends of the bracing means occurring during pivoting of the subframe must be smaller than the length changes of the bracing means made possible by the self-elongation. However, in order to define a horizontal axis of rotation 15, the bracing cables must engage at least approximately at a common point on the upper frame.

The connection of the traction means 3 is preferably also via universal joints, however, is sufficient for pivoting about the rotation axis 15 and a simple hinge or a simple anchoring of the traction means 3 on the subframe. 2

By actuating the traction means 3, pivoting of the subframe 2 about the horizontal axis of rotation 15 can now take place without the length of the traction ropes 4 having to be changed or adjusted. This allows easy control of the lifting device, in particular, a single drive can be used for the four Verspannmittel 4. A frame in the pivoted state shows Fig. 16 , For this purpose, the length of the in the Fig. 16 shortened right traction means and those of the left traction means be extended. The traction means, which engage on one side of the subframe, have one of the traction means, which act on the other side of the subframe, independent drive.

Like the example Fig. 17 shows it is not essential that the common point of attack 5 two Verspannseile 4 is arranged centrally on the lower frame between the points of attack of the traction cables 3. In the embodiment of Fig. 15 is the axis of rotation 15 defined by the two points 5 of the Verspannseile 4 not above the geometric center of gravity of the subframe 2. Also, it is not absolutely necessary to use four traction cables 3, basically satisfy three. Also, the traction cables 3 are not arranged in the corner region of the loading platform, but each form together with the point of application 5 of two Verspannseile 4 a so-called. Triple point. A third pull rope is laterally spaced from the axis of rotation 15 in the region of the outside of the subframe 2. This embodiment is preferred because only one laterally spaced pull rope must be actuated for pivoting the load, which also has its own drive for this purpose. The Fig. 18 and 19 show the side and front view of the device according to the invention.

As the connection of the tensioning and traction means can be done at the triple point shows FIGS. 20 and 21 in detail. As in Fig. 13 This is also a universal joint, wherein the traction means 3 is connected to the sub-frame 2 via an axis 17 which is identical to an axis of the universal joint.

The FIGS. 22 to 25 In order to reach the pivoted state, in this preferred embodiment, only the traction means spaced from the axis of rotation 15 must be actuated. The length of all other tension and tensioning means remains constant. As can be seen from the detailed views, the joint in the triple point is connected to the subframe such that the subframe is rotatable with respect to the joint about the axis of rotation 15. In order to perform a simple pivoting in the other direction, a fourth traction means can be provided which engages on the opposite side of the subframe.

It is not absolutely necessary that the axis of rotation 15 defined by the points of application 5 of the bracing cables 4 is oriented parallel to the vehicle longitudinal axis. In principle, any orientation is possible, however, especially in the vehicle end assembly pivoting only about the vehicle longitudinal axis and in the vehicle immersion pivoting transverse to the vehicle longitudinal axis of importance.
In addition to the construction described, of course, further tensioning and tensioning means may be provided in order to increase safety or to improve the stability. In this context, reference is made to the front part of the description.

The Fig. 26 shows a preferred embodiment of the invention. For this purpose, first a few words regarding the drive are to be said. When lifting and lowering the subframe, cables of the tensioning and tensioning means are rolled up or down on motorized drums. In the event that only one stroke movement is provided, it is sufficient if there is a separate drive unit for the traction means and the tensioning means. In each case, the drums for the traction means and the drums for the tensioning means are mechanically coupled with respect to the rotational movement. In the event that in addition to the hub also a pivoting about a horizontal axis to be made possible, two mechanically independent drum drives are needed for the traction means. See for example Fig. 17 for the two ropes opening in the triple points a motor 30 and for the laterally arranged rope an independent motor 30 '.

As previously mentioned, it is necessary to keep the tensioning means constantly under tension to make the load lifting device insensitive to lateral forces. The preload force must be greater than the transverse forces acting on the subframe. In the present invention, it is only necessary to keep the two pairs of pointers taut. The prerequisite is that they always extend or shorten to the same extent.

Another consideration in this context relates to the use of non-contact power transmission systems, which are increasingly used in the automotive industry, but at high currents are disproportionately expensive. It therefore makes sense to use energy storage.

Ultimately, it is necessary to increase the safety of the system, as is working on or under these Hubgehängen. Failure of a system component (e.g., the drive motor) should not result in a dangerous condition for workers.

The in the Fig. 26 schematically illustrated embodiment combines these aspects in a very elegant way. It is explicitly pointed out that the following explanations are not limited to the combinations and arrangements of tension and tensioning means shown. It may equally apply the use of a pressure accumulator as described below in all applications involving the lifting and lowering of loads.

Indicated at 18 is a motor-driven drum for traction means (the motor is not shown for clarity, but its effect indicated by the circular arrow), which is rotatably connected to a threaded nut 19. The threaded nut 19 during rotation of the drum 18 displaces a threaded spindle 20 prevented from rotating. The threaded spindle 20, in turn, acts on the piston of a hydraulic cylinder 21 which, for energy storage, transfers its contents to a pressure-biased accumulator 22, e.g. a bladder accumulator, piston accumulator, diaphragm accumulator, spring accumulator u. Like., Promotes. The energy wasted during the downward movement is conserved in the memory and used again when lifting the load. In addition to the substantially incompressible pressure medium, the reservoir also contains compressible or (spring) elastic means which can also absorb or dampen shocks.

If, as in the case of pivoting, two or more independently driven drums are provided for two or more groups of traction cables, correspondingly more drum units can lead into the pressure accumulator. Two of them are in Fig. 30 shown.

• Zwischen dem Zylinder 21 und dem Druckspeicher 22 ist ein Ventil 23, z.B. 2/2 Wegeventil, geschaltet, welches die Verbindung des Zylinders 21 mit dem Druckspeicher 22 bei Stillstand schließt und dabei gleichzeitig als hydraulische Bremse wirkt. Zwischen dem Zylinder 21 und dem Druckspeicher 22 ist weiters eine Sicherheitsschaltung 24 vorgesehen, beispielsweise eine Drossel zusammen mit einem Staudruckmesser oder ein Durchflussmesser. Bei einem zu hohen Staudruck bzw. zu hoher Geschwindigkeit des Druckmittels in der Druckleitung, was einer erhöhten Geschwindigkeit des Unterrahmens entspricht, wird das Ventil geschlossen und damit die Hubbewegung zuverlässig beendet. Mit der strichlierten Linie ist schematisch eine Steuerleitung zum Ventil 23 dargestellt, welches entsprechende Informationen in bezug auf den Druckmittelfluss zwischen Zylinder und Druckspeicher liefert.

Several variants described below may be implemented independently or simultaneously to achieve one or more of the above purposes:

• Between the cylinder 21 and the accumulator 22, a valve 23, for example 2/2 way valve, connected, which is the connection of the cylinder 21 to the accumulator 22 at standstill closes while acting as a hydraulic brake. Between the cylinder 21 and the accumulator 22, a safety circuit 24 is further provided, for example, a throttle together with a dynamic pressure gauge or a flow meter. At a high back pressure or too high speed of the pressure medium in the pressure line, which corresponds to an increased speed of the subframe, the valve is closed and thus the lifting movement ended reliably. The dashed line schematically shows a control line to the valve 23, which provides corresponding information with respect to the pressure medium flow between the cylinder and pressure accumulator.

The Fig. 27 to 29 show a possible embodiment of a drum, in the interior of the hydraulic cylinder is integrated. The helical grooves for tension or tensioning cables are denoted by 25. On average of Fig. 28 the connection device 26 is shown for a motor, the spindle nut 27, which acts on the spindle 28 and the hydraulic cylinder 29, the piston is displaced during the rotation of the drum 18 of the spindle 28. Of course, other known to those skilled transfer mechanisms of a rotary motion in a translational movement are conceivable.

In the example shown the Fig. 17 are the drums, from which the Verspannseile 4 are unrolled, mechanically coupled in their rotational movement. Their length can therefore only ever be changed to the same extent. Therefore, in this case in Fig. 26 and 30 provided only a single cylinder. However, a plurality of mechanically coupled and therefore concurrent drums may be connected to the illustrated drum 32 (in Figs Fig. 17 indicated).

In other than in the Fig. 17 illustrated preferred embodiment in which a plurality of independently operable Verspannmittel are provided (to allow, for example, a pivoting in other horizontal axes), then it is of course possible to connect each independently drivable group of Verspannseilen about its own hydraulic cylinder with the pressure accumulator ,

It is important to note that it is not absolutely necessary to discharge various hydraulic cylinders into the same accumulator. To achieve efficient shock absorption, each driven drum or drum group could also have their own separate accumulators from the others.

Now, when the downward movement of the lower frame 2, the piston of the cylinder 21, 21 'urge the pressure medium in the pressure accumulator, pressure energy is generated and stored, which is then available again when moving up the load and supports the engine. At the same time - assuming an open valve 33 - the pressure energy is also transmitted to the drum 32 or the drums of Verspannseile which are driven by and keep the tension cables under constant train.

The drives for tension and Verspannmittel are in the above embodiment still mechanically independent of each other, ie in the sense that they perform independent rotational movements, only and the energy required for the drive is provided by a single motor.

As mentioned above, the use of a pressure accumulator is not for use in a system according to Fig. 17 limited. Any conceivable arrangement, number and combination of tension cables and, if appropriate, tensioning cables can be improved by the use of a pressure accumulator with respect to their damping properties.

With increasing energy consumption due to heavier loads and increasing dead weight of lifting devices, as well as by the requirement of rapid movements of the load, the inventive design represents a cost and energy-saving measure.

Another advantageous effect of this embodiment is that strong shocks, collisions u. Like. Can be collected by the hydraulic system. In this context, the pressure accumulator acts as a buffer and protects the entire construction from damage.

Of course, all the elements described above can also be used individually. For example, only the drums for the tension cables or only the drums for the traction cables are coupled to a pressure accumulator, etc.

The measure makes it possible - and this works only when using combined to pointer pairs Verspannmittel a hoist for the automotive industry which is lightweight, stable, cost-effective and safe and, above all, can be pivoted about a horizontal axis without significant additional costs.

Claims (13)

1. A load lifting device, especially for the automobile industry, with an upper frame (1) and a lower frame (2) positioned below it, wherein the lower frame (2) is held on the upper frame (1) by at least three essentially vertical traction elements (3) and at least four tensioning elements (4) that run obliquely to the vertical and can be moved vertically by driving the traction elements (3) and tensioning elements (4), and wherein two tensioning elements (4) are attached, at least approximately, to a common point (5) on the lower frame (2), furthermore the ends of the two tensioning elements (4) terminate at a joint (14), which is connected to the lower frame (2) and allows rotation of the lower frame (2) relative to the tensioning elements (4) around an axis of rotation (15) which is defined by the two points of attachment (5) of the tensioning cables (4) to the lower frame (2), characterized in that a traction element (3) is attached, at least approximately, to each of the two points of attachment (5) that define the axis of rotation (15) and forms a triple point together with two tensioning elements (4) attached to each point of attachment.
2. A load lifting device according to claim 1, characterized in that, to allow the tilting of the lower frame (2), at least one vertical traction element (3) has a drive that is independent of the other vertical traction elements.
3. A load lifting device according to claim 1 or 2, characterized in that the system consisting of the upper frame (1), the lower frame (2), the traction elements (3), and the tensioning elements (4) is kinematically determined and preferably kinematically overdetermined.
4. A load lifting device according to one of claims 1 to 3, characterized in that the line connecting the two points of attachment (5) of the tensioning elements (4) passes essentially through the vertical projection of the center of gravity of the lower frame (2) onto the horizontal plane that contains the points of attachment.
5. A load lifting device according to one of claims 1 to 4, characterized in that the outline of the tensioning elements (4) vertically projected onto the horizontal plane of the center of gravity of the lower frame (2) contains the center of gravity of the lower frame (2).
6. A load lifting device according to one of claims 1 to 5, characterized in that four tensioning elements (4) are provided, which extend from the upper frame (1) to the lower frame (2) essentially along the edges of a preferably regular tetrahedron.
7. A load lifting device according to one of claims 1 to 6, characterized in that all of the tensioning elements (4) have essentially the same length, at least when the upper frame (1) and the lower frame (2) are in a parallel position.
8. A load lifting device according to one of claims 1 to 7, characterized in that the drive of one or more traction elements (3) is hydraulically coupled to a pressure accumulator (22) via a hydraulic cylinder (21, 21').
9. A load lifting device according to one of claims 1 to 8, characterized in that the drive of one or more tensioning elements (4) is hydraulically coupled to a pressure accumulator (22) via a hydraulic cylinder (21, 21').
10. A load lifting device according to one of claims 1 to 8, characterized in that the drive of the tensioning elements (4) is hydraulically powered by the pressure energy stored in the pressure accumulator (22).
11. A load lifting device according to claim 8 or 9, characterized in that a safety circuit, which closes the pressure line when a certain fluid flow is exceeded, is provided between the hydraulic cylinder (21, 21') and the pressure accumulator (22).
12. A load lifting device according to one of claims 9 to 11, characterized in that the drive of the traction elements (3) and the drive of the tensioning elements (4) are coupled to the same pressure accumulator (22).
13. A load lifting device according to one of claims 8 to 12, characterized in that the traction elements (3) and possibly the tensioning elements (4) are driven by one or more drums (18, 18', 32), wherein the rotational motion of the drums acts on the piston of a hydraulic cylinder (21, 21', 31) via a spindle (20) and vice versa.

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