DK1543744T3

DK1543744T3 - Bed lifting device

Info

Publication number: DK1543744T3
Application number: DK03029130.6T
Authority: DK
Inventors: Carlos Bernal
Original assignee: Wissner Bosserhoff Gmbh
Priority date: 2003-12-18
Filing date: 2003-12-18
Publication date: 2015-07-13
Also published as: EP1543744B1; EP1543744A1; ES2540899T3

Description

The present invention relates to a lifting device for beds, in particular for patient and nursing beds. A lifting device of this type is known from printed publication DE 296 05 577 U1. This printed publication discloses, in particular in Figures 5 and 6, a lifting device having a first and a second telescopic leg, wherein the legs in each case have a stationary lower leg part and an upper leg part which is movable in relation to the former. The legs are here interconnected via a cross member. In addition, the lifting device has a rotational drive for the simultaneous length adjustment of the legs of the lifting device. For the length adjustment by means of the rotational drive, moreover, a first and a second traction means are used. To this end, the traction means are guided from the rotational drive via two deflection rollers fixedly mounted in the lower leg part and a deflection roller mounted on the lower end of the lower leg part. In the region between one of the two upper deflection rollers and the lower deflection roller, the traction means is fastened by its two ends to a common fastening point on the upper leg part. As a result of a pulling movement on the traction means due to a rotation of the rotational drive, the common fastening point of the traction means is then displaced relative to the upper deflection rollers and the lower deflection roller. As a result, the upper leg part is displaced in the lower leg part and the lifting device performs a lifting movement. A drawback is that the described lifting device has legs which can be easily telescoped. Only relatively low adjustment heights are achievable in this case. A lifting device having the features of the preamble of Claim 1 is further known from the printed publication having the publication number DE 87 63 21 C. This printed publication discloses a lifting device for a height-adjustable table, which has easily telescopable legs with which only relatively low adjustment heights, which are insufficient, for instance, for beds which are used in the field of care for the elderly or patient care, are achievable.

Further lifting devices are known from the printed publications having the publication numbers DE 44 05 508 Al, DE 101 02 484 Al, DE 22 04 299 A and DE 83 10 826 Ul, all of which have only easily telescopable legs predominantly for height-adjustable tables.

From printed publication DE 91 10 687 Ul, stand-alone doubly telescopic legs are known. The legs disclosed in this printed publication require for each doubly telescopic leg at least two traction means such as cables, chains or V-belts. This has the effect, for example, insofar as the doubly telescopic legs disclosed in the last-named printed publication are used in a device according to the first-named printed publication, that a total of four traction means have to be used. This results in a considerable complexity of assembly and design, which it is important to minimize.

The object of the invention is therefore to propose a lifting device which is simple in design and the legs of which can be constructed also to be doubly telescopic, without great additional design or assembly complexity.

This object is achieved according to the invention by a lifting device according to Claim 1. According to this, in a lifting device according to the invention, a first end of the first traction means or of the second traction means, respectively, is attached to the lower end of the upper leg part of the second leg or of the first leg, respectively. By contrast, a second end of the first traction means or of the second traction means, respectively, is at least indirectly attached to the upper leg part of the first leg or of the second leg, respectively. Moreover, the first traction means and the second traction means intersect one another in the region between the first and the second leg. The device according to the invention has doubly telescopic legs in order to achieve a greater lift alongside a compact construction. To this end, the legs in each case comprise a central leg part, which is in each case movable in relation to the lower leg part and the upper leg part.

The basic principle of the device according to the invention consists in the fact that, by means of the rotational drive, the first traction means or the second traction means, respectively, is drawn from the first leg or to the second leg, respectively, and the upper leg parts of the legs are thereby displaced downwards or upwards, respectively, in relation to the lower leg parts.

In order to further improve the working of the device according to the invention, the device has a first group of deflection rollers and a second group of deflection rollers. The first group of deflection rollers comprises a deflection roller, denoted as the third deflection roller, in the region of the lower end of the central leg part of the second leg, and the second group of deflection rollers comprises a deflection roller, denoted as the third deflection roller, in the region of the lower end of the central leg part of the first leg.

The individual deflection rollers of the first group can be arranged in the lifting device as follows: At least one first deflection roller is fitted in the region of the lower end of the lower leg part of the first leg. A second deflection roller of the first group of deflection rollers can be fitted in the region of the upper end of the lower leg part of the second leg. The second group of deflection rollers can comprise at least one first deflection roller in the region of the lower end of the lower leg part of the second leg, whilst a second deflection roller can be fitted in the region of the upper end of the lower leg part of the first leg.

In a device according to the invention, the first traction means can then run from its second end, via the at least one first deflection roller of the first group, the rotational drive and the second deflection roller of the first group, to the first end of the first cable. Analogously thereto, the second traction means can be guided from its second end, via the at least one first deflection roller of the second group, the rotational drive and the second deflection roller of the second group, to the first end of the second traction means.

Furthermore, the first group of deflection rollers can comprise a fourth deflection roller, which is arranged in the region of the upper end of the central leg part of the second leg part. Analogously thereto, the second group of deflection rollers can comprise a third deflection roller in the region of the lower end of the central leg part of the first leg, and advantageously a fourth deflection roller in the region of the upper end of the central leg part of the first leg.

In such a lifting device having doubly telescopic legs, the first traction means, between the second deflection roller of the first group and the second end, can be guided via the third deflection roller and the fourth deflection roller. Analogously, the second traction means in such a lifting device, between the second deflection roller of the first group and its second end, can be guided via the third deflection roller and the fourth deflection roller.

As a result of the doubly telescopic leg, a large lift of the lifting device can be achieved alongside simultaneously compact construction of the lifting device. At the same time, the legs of the lifting device are adjustable in their length with in each case only one traction means, such as, for instance, a cable, a chain or a V-belt.

The first traction means and the second traction means of a lifting device according to the invention can be drivable via a drive roller of the rotational drive. It is here possible that the first and the second traction means is non-positively connected to the drive roller and the non-positive connection is sufficient for the force to be transmitted from the drive roller to the traction means in order to drive the traction means in the one or in the other direction. In order that an effective non-positive connection is established between the drive roller and the traction means, the traction means preferably wrap around the drive roller several times over.

In an alternative embodiment, the traction means can also be secured on the drive roller, for example by clamping. This can be realized, for instance, via a radial borehole through the drive roller, through which the traction means are guided. The non-positive connection is then thereby improved and the risk of slippage of the traction means on the drive roller is reduced.

The drive roller can either be driven directly by a drive shaft, or else it is equally possible for the drive roller to be driven by a drive shaft via a belt. The drive shaft preferably extends from a transmission which is driven by a motor . A lifting device according to the invention can comprise a brake, which preferably brakes the movement of the lifting device as the legs are retracted or prevents sagging of the moving parts of the lifting device when the rotational drive is at rest. If a brake is not provided, in addition to the force applied by the drive, gravitational force also acts to retract the legs, whereby the retraction movement of the legs can be strongly accelerated. Namely, in addition to the gravitational force of the moving parts of the lifting device, the gravitational force of the bed frame and of a person lying in the bed is possibly also at play. A brake has the advantage that it acts counter to the gravitational force of the moving parts of the lifting device, of the mattress frame and of the person lying on the bed, and thus prevents sagging of the lifting device, as a result of the gravitational force, when the lifting device is at rest.

The brake of a lifting device according to the invention can here have a wrap spring. The wrap spring is mounted on the drive shaft, and at the same time fastened by one end to a non-rotating part, such that, upon extension of the lifting device, the wrap spring is opened and the drive can rotate freely, whilst, upon retraction, the wrap spring is closed and the drive and the acting gravitational force must work again the force of the twisted wrap spring.

Two illustrative embodiments of a lifting device according to the invention and a nursing bed having lifting devices according to the invention is described in greater detail with reference to the drawing.

Fig. 1 shows a section through a lifting device along the line I - I in Fig. 3 in the extended state of the lifting device,

Fig. 2 shows a section through the lifting device along the line I - I in Fig. 3 in the retracted state,

Fig. 3 shows a top view of the lifting device,

Fig. 4 shows a perspective view of a nursing bed having two lifting devices according to the invention according to Figs. 1 to 3,

Fig. 5 shows a side view of the bed according to Fig. 4,

Fig. 6 shows a front view of the bed according to Figs. 4 and 5,

Fig. 7 shows a view of both lifting devices, connected via longitudinal members, of the bed according to Figs. 4 to 6,

Fig. 8 shows a top view of a second lifting device according to the invention,

Fig. 9 shows a section through the lifting device according to Fig. 8 along the line IX-IX in the extended state,

Fig. 10 shows a section through the lifting device according to Fig. 8 along the line IX-IX in the retracted state,

Fig. 11 shows the lifting device according to Figs. 8 to 10 along the line IX-IX in the rolling position,

Fig. 12 shows the second lifting device according to Figs. 8 to 11 in the section along the line XII-XII in Fig. 7,

Fig. 13 shows a top view of the lifting device according to Figs. 8 to 12, the upper cross member having been removed,

Fig. 14 shows a detail from Fig. 13 according to XIV-XIV, and

Fig. 15 shows a detail of the second lifting device according to Figs. 8 to 14 in perspective representation.

The nursing bed represented in Figures 4 to 6 has two lifting devices, which comprise doubly telescopic legs. The individual limbs of the legs (leg parts) of a lifting device are concealed by covers 48 to 53. The foot-end lifting device has for this purpose a lower cover 51, a central cover 52 and an upper cover 53. The head-end lifting device is concealed by a lower cover 48, a central cover 49 and an upper cover 50. The two lifting devices 1 are connected to each other via longitudinal members 54, 55, of which in Fig. 4 only the longitudinal member 54 is discernible. To the upper ends of the lifting device is attached a frame of the nursing bed, which consists of a right frame part 45, a left frame part 46 and a foot-end part 47a, as well as a head-end part 47. On the frame is arranged a supporting surface for a mattress, which is formed by the supporting parts 41, 42, 43, 44. A first supporting part 41 serves to support the trunk of a bed occupant and is preferably configured to be adjustable in height. The foot-end supporting parts 43, 44 are likewise preferably configured to be adjustable and serve to support the thigh and lower leg, respectively, of a bed occupant. The bed according to Figures 4 to 6 is represented in Fig. 7 without the right frame part 45, the left frame part 4 6, the head part 47, das foot part 47a and the supporting parts 41, 42, 43, 44. This leaves, therefore, the lifting devices 1, which are connected to each other via the longitudinal members 54, 55 and which are of similar configuration and are described in greater detail below with reference to Figures 1 to 3 .

Each of the lifting devices 1 is equipped with castors 2, whereby the lifting devices 1, and thus also the beds 40, are displaceable. The castors 2 are attached via pivot bearings 3 pivotably to a castor carrier 4.

The lifting devices 1 respectively have a first and a second doubly telescopic leg, each having a lower leg part 7a, 7b, a central leg part 8a, 8b and an upper leg part 9a, 9b. The lower leg part 7a of the first leg is fixedly connected via a lower cross member 5 and a central cross member 6, in a framelike manner, to the lower leg part 7b of the second leg. To the outer side of the lower leg part 7a of the first leg and of the leg part 7b of the second leg are attached the castor carriers 4 of the castors 2.

The lower leg part 7a of the first leg and the lower leg part 7b of the second leg are of substantially tubular configuration. The inside diameter of the lower leg part 7a of the first leg and of the lower leg part 7b of the second leg is here dimensioned such that the central leg part 8a of the first leg is displaceably mounted in the lower leg part 7a of the first leg and, analogously, the central leg part 8b of the second leg is displaceably mounted in the lower leg part 7b of the second leg.

The central leg part 8a of the first leg and the central leg part 8b of the second leg are also of tubular configuration. The central leg parts 8a, 8b here respectively have an inside diameter which is dimensioned such that the upper leg part 9a of the first leg or the upper leg part 9b of the second leg, respectively, is displaceable in the respective central leg part 8a, 8b of the first or of the second leg, respectively. The upper ends of the upper leg parts 9a, 9b are moreover fixedly connected to each other with an upper cross member 10. As a result, the first and the second leg can only be extended or retracted parallel to each other.

To the lower end of the lower leg part 7a, 7b of the first leg or of the second leg, respectively, is attached on the inner side, that is to say between the walls of the respective leg part 7a, 7b, an outer first deflection roller 12, 22. Inwardly offset from this outer first deflection roller 12, 22, directly outside the respective lower leg part 7a, 7b, an inner first deflection roller 13, 23 is fastened to the lower carrier 5. In addition, second deflection rollers 14, 24 are attached to the central cross member 6 directly adjacent to the upper ends of the lower leg parts 7a, 7b. Moreover, to the lower ends of the central leg parts 8a, 8b are attached third deflection rollers 15, 25, wherein these third deflection rollers 15, 25 are fastened to the central leg parts 8a, 8b such that they are guided in an inner longitudinal slot of the lower leg parts 7a, 7b. Finally, fourth deflection rollers 16, 26 are attached to the upper ends of the central leg parts 8a, 8b, wherein these fourth deflection rollers 16, 26 intrude within the lower ends of the upper leg parts 9a, 9b. For the fastening of these fourth deflection rollers 16, 26, the central leg parts 8a, 8b have a tube, which, concentrically to the outer wall of the central leg parts 8a, 8b, at the lower end of the central leg parts, is connected to the outer wall and has an outside diameter which is smaller than the inside diameter of the upper leg parts 9a, 9b, so that this tube, fastened concentrically to the lower end of the central leg parts 8a, 8b, can intrude, in the retracted state of the lifting device 1, into the upper leg parts 9a, 9b.

On the central cross member 6 is provided a drive means, with which the lifting device 1 can be extended or retracted. The drive means has for this purpose a motor 32, which is connected via a transmission 31 to a drive shaft 30, the axis of which runs perpendicular to the central cross member 6. Fastened on the drive shaft 30 is a drive roller 20. Directly adjacent to this drive roller 20 is fitted a pressure roller 19, the rotational axis of which likewise runs perpendicular to the central cross member 6, the pressure roller 20 being mounted on the cross member.

The lifting device 1, as is represented in Figures 1 to 3, is completed by a first cable 11 and a second cable 21. These cables 11, 21 are respectively assigned a group of deflection rollers, wherein the first cable 11 is assigned the outer first deflection roller 12, the inner first deflection roller 13, the second deflection roller 14, the third deflection roller 15 and the fourth deflection roller 16. The second group of deflection rollers, which is assigned to the second cable 21, includes the outer first deflection roller 22, the inner first deflection roller 23, the second deflection roller 24, the third deflection roller 25 and the fourth deflection roller 26.

The first cable 11 is arranged in the lifting device as follows. The first cable 11 is fastened by a first end 17 to the lower end of the upper leg part 9b. Starting from there, it is guided upwards to the fourth deflection roller 16. As a result of the deflection roller, the first cable 11 has its direction reversed downwards to the third deflection roller 15, which is fastened to the lower end of the central leg part 8b. Here too, the first cable 11 is deflected through 180°, so that it hereafter runs upwards to the second deflection roller 14. Starting from the second deflection roller 14, the first cable 11 is guided several times around the drive roller 20, from which the first cable is guided via the pressure roller 19 to the inner first deflection roller 13. From the inner first deflection roller 13, the first cable then runs horizontally to the outer first deflection roller 12, from which the first cable is guided upwards so as to be fastened by its second end 18 to the upper cross member 10.

The second cable 21 is arranged substantially in mirror image to the first cable 11, wherein it is guided via the deflection rollers of the second group of deflection rollers 22, 23, 24, 25, 26. Accordingly, the first end 27 of the second cable 21 is fastened to the lower end of the upper leg part 9a. From there it runs upwards to the fourth deflection roller 26, which the second cable 21 leaves directed downwards to the third deflection roller 25, which deflects the second cable 21 once again through 180°. Then the second cable 21 is guided to the second deflection roller 24. The second cable 21 leaves the second deflection roller 24 directed horizontally to the middle of the central cross member 6, so as then to be guided several times around the drive roller 20. From the drive roller 20, the second cable 21 is then guided to the inner first roller 23, and from there to the outer first roller 22. The second cable 21 then leaves the outer first deflection roller 22 in the upward direction, so as, analogously to the first cable 11, to be fastened by its second end 28 to the upper cross member 10.

As a result of a rotation of the drive roller 20 due to a start-up of the motor 32, the first cable 11 is moved from the second deflection roller 14 to the first inner deflection roller 13, and at the same time the second cable 21 is moved from the first inner roller 23 to the second deflection roller 24, or vice versa, depending on the direction of rotation. Here, for the transfer of the torque from the drive roller 20 to the first cable 11 or the second cable 21, only the friction force acting between the respective cable 11, 21 and the drive roller 20 is utilized. This friction force is increased by the multiple lappings of the drive roller 20 by the first cable 11 and the second cable 21. The pressure roller 19 here has the function of ensuring that the (radial) forces which act on the drive shaft 30 via the first cable 11 or the second cable 21, respectively, are directed symmetrically counter to each other, and thus cancel each other out. It is thereby possible to mount the drive shaft merely in the transmission 31. In an advantageous embodiment of a lifting device according to the invention, the same strategy is adopted. However, it is equally possible, with the omission of the pressure roller 19, to guide the first cable 11 from the inner first deflection roller 13 directly to the drive roller 20. It is then necessary, however, for the drive shaft 30 not only to be mounted in the transmission 31, but also by its opposite end.

By an anti-clockwise rotation of the drive roller 20, the first cable 11 is drawn from the first leg 7a, 8a, 9a in the direction of the second leg 7b, 8b, 9b. At the same time, the second cable 21 is moved in the opposite direction, that is to say from the second leg 7b, 8b, 9b to the first leg 7a, 8a, 9a. In an extended lifting device as is represented in Fig. 1, this leads to a shortening of the cross member 10 as a result of the shortening of the cable portion between the second end 18 of the first cable 11, or the second end 28 of the second cable 21, and the respective outer first deflection roller 12, 22. The cross member is thereby drawn downwards. The cable length gained by the drawing down of the cross member 10 between the second end 18 or 28 and the outer first deflection rollers 12 or 22 is drawn in the direction of the second deflection rollers 14 and 24 by the movement of the drive roller 20. As a result of the downward movement of the cross member 10, the lower end of the upper leg parts 9a, 9b is moved downwards and the upper leg parts 9a, 9b intrude into the central leg parts 8a, 8b. As a result, the distance between the lower end of the upper leg parts 9a, 9b, to which the first ends of the first cable 11 or of the second cable 21, respectively, are attached, and the fourth deflection rollers 16 and 26, respectively, is lengthened. The lengthening of the distance here corresponds exactly to the length by which the distance between the upper cross member 10 and the outer first deflection roller is shortened. As a result of the pulling movement on the first cable 11 or the second cable 21, respectively, the cable length gained by the shortening of the distance between the second end 18 or 28 and the first outer deflection roller 12 or 22 is eaten up by the enlargement of the distance between the first end 17 or 18 of the cable 11, 21 and the fourth roller 16 or 26.

If, after a certain period of anti-clockwise rotation of the drive roller 20, the lower end of the upper leg parts 9a, 9b is fully immersed in the central leg parts 8a, 8b and, at the same time, the upper end of the central leg parts 8a, 8b is in abutment against the cross member 10, no relative movement is any longer possible between the upper leg parts 9a, 9b and the central leg parts 8a, 8b. If, however, the drive movement is continued by the motor 32 and the drive roller 20 continues to rotate anti-clockwise, a relative movement between the central leg parts 8a, 8b and the lower leg parts 7a, 7b begins. As a result of the continued pulling movement of the first cable 11 from the first leg 7a, 8a, 9a and to the second leg 7b, 8b, 9b of the second cable 21 from the second leg 7b, 8b, 9b to the first leg 7a, 8a, 9b, the cross member 10 is drawn further downwards. The central leg parts 8a, 8b hereupon intrude into the lower leg parts 7a, 7b. The cable length gained by the shortening of the distance between the cross member 10 and the outer first rollers 12, 22 is then compensated by an enlargement of the distance between the second deflection rollers 14, 24 and the third deflection rollers 15, 25.

Moreover, it is also possible that, upon the retraction movement of the lifting device 1, the central leg parts 8a, 8b are first displaced into the lower leg parts 7a, 7b, before the upper leg parts 9a, 9b are drawn into the central leg parts 8a, 8b by the pulling movement on the first cable 11 or the second cable 21, respectively.

If, however, in particular in a retracted lifting device (Fig. 2), the drive roller 20 rotates clockwise, the first cable 11 is drawn from the second leg 7b, 8b, 9a in the direction of the first leg 7a, 8a, 9a. At the same time, the second cable 21 is drawn from the first leg 7a, 8a, 9b in direction of the second leg 7b, 8b, 9b. As a result of the pulling movement of the first cable 11, from the second leg 7b, 8b, 9b to the first leg 7a, 8a, 9a, the distances, on the one hand, between the second deflection roller 14 and the third deflection roller 15 and, on the other hand, between the third deflection roller 15 and the fourth deflection roller 16 shorten one after another or at the same time. As a result of the simultaneous pulling movement of the second cable 21, the corresponding distance between the second deflection roller 24 and the deflection roller 25 or between the third deflection roller 25 and the fourth deflection roller 26, respectively, shortens. As a result, the upper cross member 10 moves upwards and the lifting device 1 is extended. The cable length gained as a result of the pulling movement of the cables 11, 21 and the shortening of the distances between the respective second deflection roller 14 or 24 and the third deflection roller 15 or 25, on the one hand, and the respective third deflection roller 15 or 25 and the respective fourth deflection roller 16 or 26, on the other hand, is compensated by the enlargement of the distance between the second end 18, 28 of the first cable 11 or of the second cable 21, respectively, and the outer first deflection rollers 12, 22.

That lifting device according to the invention which is represented in Figures 8 to 15 corresponds in its basic structure to the lifting device according to Figures 1 to 3. Parts of the second lifting device according to the invention are therefore provided with the same reference symbols as parts of the first lifting device according to Figs. 1 to 3 if these parts mutually correspond in terms of their function. In particular, the structure of the legs of the second lifting device is thus similar to the structure of the legs according to the first lifting device, so that, with respect to the structure of the legs, reference is made to the description to

Figs. 1 to 3.

The guidance of the first cable 11 and of the second cable 21 in the lifting device according to Figures 8 to 15 substantially corresponds to the cable guidance in the lifting device according to Figs. 1 to 3. The fundamental difference in the cable guidance lies in the fact that, in the lifting device according to Figs. 1 and 2, the second end 18 of the first cable and the second end 28 of the second cable 21 is arranged between the two legs, and not, as in the lifting device according to Figs. 1 and 2, on the outer side of the two legs. As a result, in the two groups of rollers the respectively outer first roller, via which, in the lifting device according to Figs. 1 to 3, the first cable 11 and the second cable 21, respectively, are deflected upwards, is omitted. In the lifting device according to Figs. 8 to 15, the first cable 11 and the second cable 21 are deflected upwards directly from the then single first roller 12 or 22.

As a result of this arrangement of the second ends 18, 28 of the first cable 11 and of the second cable 21, respectively, on the inner side of the two legs 7, 8, 9, the outer first rollers can be spared in comparison to the lifting device according to Figs. 1 and 2. Hence the lifting device according to Figs. 8 to 15 is even more compact.

The lifting device according to Figs. 8 to 15 is additionally more compact than the lifting device according to Figs. 1 to 3 also by virtue of the fact that the motor 32 and the transmission 31 is arranged lying between the two legs 7, 8, 9. In contrast thereto, in the lifting device according to Figs. 1 to 3 the motor 32 and the transmission 31 is arranged at least partially in a region outside the space between the two legs 7, 8, 9, as can also clearly be seen from the representation of the nursing bed according to Figs. 4 to 7.

As a result of the different arrangement of the motor 32 and the transmission 31, and the now different spatial relationships between the two legs 7, 8, 9 of the lifting device, it has proved advantageous for the drive roller 20 to be driven via a toothed belt 34 indirectly by the drive shaft 30 which extends from the transmission 31. The drive shaft 30 has for this purpose a gearwheel 33, in which the toothed belt 34 engages. Equally, the drive roller 20 has a gearwheel 35, which is engaged with the toothed belt 34. The drive roller 20, unlike the drive roller 20 of the lifting device according to Figs. 1 to 3, has two radial boreholes. The first cable 11 or the second cable 21, respectively, is guided through these radial boreholes in the drive roller. Following their exit from the radial boreholes, the cables 11, 21 kink at a substantially right angle and are thereby clampingly secured in the borehole. That portion of the cables 11, 21 which is guided through the radial boreholes thus cannot be unreeled from the drive roller 20. In order that the cable length of the first cable 11 and of the second cable 21 between the drive roller and the first end 17, 27 and the second ends 18, 28 can be altered in the process of extending or retracting the lifting device, it is necessary to ensure that the required additional cable length can be unreeled from the drive roller 20 or that the excess cable length can be reeled onto the drive roller 20.

The lifting device according to Figs. 8 to 15 has a brake, which brakes the retraction movement of the lifting device and in so doing, in particular, compensates the gravitational forces acting on the moving parts of the lifting device. It is thereby possible to retract the lifting device at approximately the same speed as that at which it can be extended. The brake further ensures that, when the motor 32 is at rest, the extended lifting device does not sag downwards, due to forces acting on the moving parts of the lifting device, without the motor 32 being started.

As the brake, the lifting device according to Figs. 8 to 15 advantageously has a wrap spring 36. This wrap spring 36 is secured by one end to a holding element 37, which is part of an angle plate 38. This angle plate 38 is fastened via screws 39 to the lower cross member 5 of the lifting device. The wrap spring 36 is thus secured by its one end in relation to the lower cross member 5, and thus the two lower parts 7a, 7b. The wrap spring is penetrated by the drive shaft 30. The wrap spring 36 here bears so tightly against the drive shaft 30 that, following rotation of the drive shaft 30, the wrap spring is closed or open. The lifting device according to Figs. 8 to 15 is here set up such that, upon a rotary movement of the drive shaft 30, which rotary movement causes a retraction of the lifting device, the wrap spring 36 is closed and the motor 32 must work against the force applied by the wrap spring 36. Also when the motor 32 is at rest, the wrap spring 36 bears so closely against the drive shaft 30 that, if the lifting device is pressed in without the motor 32 being started, it is necessary to work against the force of the wrap spring 36. If, on the other hand, the motor 32 is started such that the lifting device is extended, the rotation of the drive shaft 30 causes the wrap spring 36 to open. The drive shaft 30 thereby becomes substantially free from a force application by the wrap spring, so that the drive shaft 30 can rotate essentially free from the wrap spring 36. The brake thus does not operate during the extension of the lifting device. A further difference between the lifting device according to Figs. 1 to 3 and the lifting device according to Figs. 8 to 15 lies in the attachment of the castors 2 to the frame formed by the legs 7, 8, 9 and the upper cross member 6 or the lower cross member 5, respectively. Whilst the castors 2 in the lifting device according to Figs. 1 to 3 are fastened directly to the frame via a castor carrier 4, the castor carriers 4 in the lifting device according to Figs. 8 to 15 are adjustable in height in relation to the frame. The castors 2 are fastened to the lower end of a tubular castor carrier 4. This castor carrier 4 is fitted in a height-adjustable manner in a bush of a supporting leg carrier 70. At the same time, fastened to the supporting leg carrier 70 are supporting legs 71, on which the bed normally rests. If the bed is due to be displaced, the lifting device must be fully retracted in order to be brought into a rolling position. Upon the retraction of the lifting device, the upper cross member 10 butts against the upper end of the castor carrier 4 . As a result of a further retraction movement of the lifting device, the upper cross member 10 presses onto the free ends of the castor carriers 4, whereby the castor carrier 4 is pressed downwards in relation to the supporting leg carrier 70. The castor carrier 4 is thereby pushed out of the bottom of the supporting leg carrier 70. The pushing out of the castor carrier 4 and of the thereto connected castors causes the supporting legs 71 to lift off the ground. The bed is then in a rolling position and can readily be displaced on the castors 2.

In order to ensure that the lifting device is not damaged in the event of uncontrolled operation of the motor 32, in the lifting device according to the invention according to Figs. 8 to 15 are provided switches 61, 62, 63, which prevents damage to the lifting device and - where the lifting device is used in a nursing bed - specific positions of the nursing bed which are dangerous for a bed occupant. The switches 61, 62, 63 are here actuated via a first actuating element 67 and a second actuating element 69, whereby the switches 61, 62, 63 interrupt the power supply to the motor 32 and switch off the lifting drive. The first actuating element 67 and the second actuating element 69 are fastened on a first rod at opposite ends. The first rod 60 is, on the one hand, guided in a guide bush 66 and, on the other hand, guided in a second rod 65, which engages in the first rod 60 and is fastened to the upper cross member 10. The first switch 61 and the second switch 62 are fastened in such a way in regard to the guide bush 66 that both the first switch 61 and the second switch 62 can be tripped solely by the second actuating element 69. The third switch 63, on the other hand, can be tripped solely by the second actuating element.

Upon the extension of the lifting device, the second rod 65, connected to the upper cross member 10, is moved upwards. The first rod 60 slides downwards on the second rod 65 under gravitational force, until a driver (not represented) on the second rod 65 draws the first rod 60 upwards. The first rod 60 then also moves upwards. A second spring 68, which is inserted between the guide bush and the first actuating element 67, here initially holds the first actuating element at a distance from the guide bush, so that the third switch 63 is not actuated. If, however, upon a further extension, the rod 60 is drawn further upwards, the second spring 68 is compressed and the first trip element acts on the third switch 63 and trips this. The motor 32 is thereby switched off. The uppermost position of the lifting device is reached.

Upon the retraction of the lifting device, the upper cross member 10 is lowered. As a result, the second rod 65 and the first rod 60 is also moved downwards. If the lifting device has reached a central position, the second actuating element 69 butts against a first spring 64. This first spring holds the second actuating element 69 at a distance from the guide bush and thus prevents actuation of the first or second switch 61, 62. Only once the second rod is retracted fully into the first rod 60 and the upper cross member 10 is pressing the first rod downwards counter to the spring pressure of the first spring 64 does the second actuating element 69 enter into the region of the first switch 61 and trip this. The lifting device has then reached its lower position. In this lower position, the lifting device rests on the supporting legs 71. If the lifting device is now to be brought into the rolling position, in which the supporting legs 71 are raised off the ground and the lifting device rests fully on the castors 2, the interruption induced by the first switch 61 has to be annulled. This can be realized, for instance, by an additional switch, in particular a key switch, which bridges the first switch 61. A device of this type is disclosed, for instance, in the printed publication having the publication number DE 41 43 182 C2. If the first switch 61 is bridged, the lifting device can be moved further downwards, to be precise to the point where the second actuating element 69 trips the second switch 62 and switches off the motor 32 again. The lifting device is now in the rolling position and can be easily disposed to another location.

Reference symbol list 1 lifting device 2 castors 3 pivot bearing 4 castor carrier 5 lower cross member 6 central cross member 7a lower leg part of the first leg 8a central leg part of the first leg 9a upper leg part of the first leg 7b lower leg part of the second leg 8b central leg part of the second leg 9b upper leg part of the second leg 10 upper cross member 11 first cable 12, 13 first deflection rollers to the first cable 14 second deflection roller to the first cable 15 third deflection roller to the first cable 16 fourth deflection roller to the first cable 17 first end of the first cable 18 second end of the first cable 19 pressure roller 20 drive roller 21 second cable 22, 23 first deflection rollers to the second cable 24 second deflection roller to the second cable 25 third deflection roller to the second cable 26 fourth deflection roller to the second cable 27 first end of the second cable 28 second end of the second cable 30 drive shaft 31 transmission 32 motor 33 gearwheel 34 toothed belt 35 gearwheel 36 wrap spring 37 holding element 38 angle plate 39 screws 40 nursing bed 41 first supporting part 42 second supporting part 43 third supporting part 44 fourth supporting part 45 right frame part 46 left frame part 47 head part 47a foot part 48, 51 lower cover 49, 52 central cover 50, 53 upper cover 54 first longitudinal member 55 second longitudinal member 60 first rod 61 first switch 62 second switch 63 third switch 64 first spring 65 second rod 66 guide bush 67 first actuating element 68 second spring 69 second actuating element 70 supporting leg carrier 71 supporting leg

Claims

1. Lifting device (1) for beds, in particular for hospital and nursing beds - with a first telescoping leg (7a, 8a, 9a) and a second telescoping leg (7b, 8b, 9b), each having a fixed lower leg ( 7a, 7b) and a movable upper leg portion (9a, 9b), with at least one transverse carrier (5, 6, 10) connecting the legs (7, 8, 9) to one another with a rotary drive (19, 20, 30 to 35) for simultaneous length adjustment of the legs (7, 8, 9) of the lifting device (1), - with a first pulling means (11) and a second pulling means (21), - a first end (17, 27) arranged on the first pulling means (11) or the second pulling means (21) on the lower end of the upper leg member (9b, 9a) on the second leg (7b, 8b, 9b) or on the first leg (7a, 8a); 9a), wherein a second end (18, 28) of the first pulling means (11) or of the second pulling means (21) is arranged at least indirectly on the upper leg part (9b, 9a) of the first leg (7a, 8a, 9a) or on the other leg (7b, 8b, 9b), and - the first pulling means (11) and the second pulling means (21) intersecting in the region between the first leg (7a, 8a, 9a) and the second leg (7b, 8b, 9b) - the lifting device having a first group of guide rollers (12 to 16) and a second group of guide rollers (22 to 26), - the first group of guide rollers (12 to 16) being one of the first pulling means (11), and the a second group of guide rollers belongs to the second pulling means (21), the first pulling means (11) or the second pulling means (12) being pulled from the first leg (7a, 8a, 9a) towards the second leg (7b, 8b) , 9b) and vice versa by means of the rotary drive (19, 20, 30 to 35), thereby displacing the upper leg portions (9b, 9a) of the legs relative to the lower leg portions (7a, 7b) downward or upward, characterized by that the legs (7a, 8a, 9a; 7b, 8b, 9b) each have a middle leg member (8a, 8b), each of which can be moved relative to the lower leg member (7a, 7b) and to the upper leg member (9a, 9b) that the first a group of guide rollers (12 to 16) comprises a third guide roller (15) in the region at the lower end of the middle leg portion (8b) of the second leg, and the second group of guide rollers (22 to 26) comprises a third guide roller ( 25) in the region at the lower end of the middle leg portion (8a) of the first leg.

Lifting device according to claim 1, characterized in that the first group of guide rollers (12 to 16) comprises at least one first guide roller (12, 13) in the region at the lower end of the lower leg part (7a) of the first leg. (7a, 8a, 9a).

Lifting device according to claim 1 or 2, characterized in that the first group of guide rollers (12 to 16) comprises a second guide roller (14) in the region at the upper end of the lower leg part (7b) of the second leg (7b). 8b, 9b).

Lifting device according to one of claims 1 to 3, characterized in that the second group of guide rollers (22 to 26) comprises at least a first guide roller (22, 23) in the region at the lower end of the lower leg part (7b). on the second leg (7b, 8b, 9b).

Lifting device according to one of claims 1 to 4, characterized in that the second group of guide rollers (22 to 26) comprises a second guide roller (24) in the region at the upper end of the lower leg part (7a) of the first leg ( 7a, 8a, 9a).

Lifting device according to one of claims 1 to 5, characterized in that the first group of guide rollers (12 to 16) comprises a fourth guide roller (16) in the region at the upper end of the middle leg part (8b) of the second leg part.

Lifting device according to one of claims 1 to 6, characterized in that the second group of guide rollers (22 to 26) comprises a third guide roller (25) in the region at the lower end of the middle leg part (8a) of the first leg.

Lifting device according to one of claims 1 to 7, characterized in that the second group of guide rollers (22 to 26) comprises a fourth guide roller (26) in the region of the upper end of the middle leg part (8a) of the first leg.

Lifting device according to one of claims 3 to 8, characterized in that the first pulling means (11) from its second end (18) extends over the at least one first guide roller (12, 13) in the first group, the rotation drive (19). , 20, 30 to 35) and the second guide roller (14) in the first group to the first end (17).

Lifting device according to claim 9, characterized in that the first pulling means (11) is guided between the second guide roller (14) in the first group and the first end (17) via the third guide roller (15) and the fourth guide roller (16). ) in the first group.

Lifting device according to one of claims 5 to 10, characterized in that the second pulling means (21) extends from its second end (28) over the at least one first guide roller (22, 23) in the second group, the rotation drive (19). , 20, 30 to 35) and the second guide roller (24) in the second group to the first end (17) of the second cable (21).

Lifting device according to claim 11, characterized in that the second pulling means (21) is guided between the second guide roller (24) in the first group and the first end (27) via the third guide roller (25) and the fourth guide roller (26). ).

Lifting device according to one of the preceding claims, characterized in that the first pulling means (11) and the second pulling means (21) can be driven via a drive roller (20) on the rotary drive (19, 20, 30 to 35).

Lifting device according to claim 13, characterized in that the drive roller (20) can be driven via a belt (34) from a drive shaft (30).

Lifting device according to claim 14, characterized in that the drive shaft (30) is driven from a gear (31) which can be driven by a motor (32).

Lifting device according to claim 13, characterized in that the first pulling means (11) and the second pulling means (21) are fixed to the drive roller (20).

Lifting device according to one of the preceding claims, characterized in that the lifting device comprises a brake.

Lifting device according to claim 17, characterized in that the brake slows down the movement of the lifting device when the legs (7, 8, 9) are driven in.

Lifting device according to claim 18, characterized in that the brake comprises a sling spring (36).