DK179579B1

DK179579B1 - Lifting device, in particular patient lifter, with an unrolling prevention device

Info

Publication number: DK179579B1
Application number: DKPA201470459A
Authority: DK
Inventors: Pahlke Lutz; Wolfrum Andreas
Original assignee: ebm-papst ZEITLAUF GmbH & Co. KG
Priority date: 2012-02-15
Filing date: 2013-02-15
Publication date: 2019-02-20
Also published as: SE1450933A2; SE1450933A1; SE539653C2; DE102012202257B4; WO2013120981A1; DK201470459A; CA2864970A1; DE102012202257A1

Abstract

A lifting device, in particular patient lifter, comprises - a drive motor (3, 4) with an output shaft (6), - a winding coil (11) to wind a lifting mechanism (13), - a rotatably mounted winding coil (11), - an abutment body (15) non-rotatably connected to the winding coil (11), and - a clamping body (24) that is radially displaceable with respect to the output shaft (6) between the abutment body (15) and a locking ring (21), said clamping body being coupled by means of a coupling arm (27), which is articulated to the output shaft (6), to the latter in such a way that = in the event of a torque (D)produced by the output shaft (6), the clamping body (24) is released from its locking position resting on the locking ring (21) and = in the event of a torque-free output shaft (6), the at least one clamping body (24) locks the mechanism owing to the load-induced counter-torque (G) on the winding coil (11).

Description

Lifting device, in particular patient lifter, with an unrolling prevention device

The invention relates to a lifting device and, in particular, a patient lifter, comprising a drive motor with an output shaft and a winding coil rotatably mounted on the output shaft to wind and unwind a lifting mechanism, which is generally realised by a lifting belt.

Lifting devices of this type are, for example, used as so-called patient lifters for transporting a disabled person.

In order to avoid an unbraked unwinding of the lifting mechanism in the event of a motor failure or a component breakage within the lifting device, lifting devices of this type have to be equipped with an unrolling prevention device, which automatically ensures a stopping of the lifting mechanism in a suitable manner, for example by a blocking of the winding coil.

Similar securing devices are also required for rolling doors, sectional doors, roller blinds or the like, which people pass through.

An example of a patient lifter with an unrolling prevention device can be inferred from EP 0 940 134 A2. The shaft of the drive motor is connected to a ratchet disc here, which has projections distributed over its periphery. These form a hook geometry that cooperates with a locking lever peripherally arranged on the ratchet disc. The ratchet disc is locked depending on the rotational speed, the locking lever being controlled due to gravity.

The problem with this unrolling prevention device is the fact that a specific rotational speed - in other words a relatively high falling speed of the lifted person - firstly has to be reached until the blocking mechanism sets in suddenly. This may entail serious injuries in terms of health for injured people moved with the aid of the patient lifter.

- 2 A rolling door securing device is known from DE 20 2004 012 024 U1, the engagement of which takes place by means of a mechanical centrifugal force control. The advantages mentioned of the prior art also apply here.

The invention is based on the object of disclosing a lifting device, which ensures a gently responding but effective unrolling prevention device in all the phases of application.

This object is achieved by the features disclosed in the characterising part of claim 1 and is characterised by

- a mounting of the winding coil that can be rotated relative to the output shaft,

- an abutment body non-rotatably connected to the winding coil,

- at least one clamping body, which can be displaced radially with respect to the output shaft between the inner abutment body and an outer locking ring, said clamping body being coupled by means of a coupling arm, which is articulated to the output shaft, to the latter in such a way that = in the event of a torque in the winding direction produced by the output shaft, the clamping body can be transferred from its locking position resting on the locking ring into a torque transmission position resting on a wedge face of the abutment body to rotate the abutment body with the winding coil independently of the load-induced countertorque acting on the winding coil, and = in the event of a torque-free output shaft, owing to the load-induced counter-torque on the winding coil, the at least one clamping body is loaded by the wedge face of the abutment body radially outwardly into the locking position resting on the locking ring with rotary blocking of the abutment body with the winding coil.

Because of this concept, the lifting device according to the invention is designed with a complete functional range as a lifting, lowering, stopping and securing unit. In this case, a separate motor brake for stopping and a separate securing

- 3 unit, such as is also used, for example, in the form of an electromagnetically activated locking element in the known unrolling prevention device according to EP 0 940 134 A2, is avoided, as is a disadvantageous, centrifugal forcecontrolled brake or lock. Because of the release and locking of the lifting device acting both in the winding and in the unwinding direction, the latter acts like a switchable freewheel acting in both directions, which reacts selectively to a torque introduction on the drive and output side. To this extent its function is, in particular, independent of the rotational direction of the drive side, on the one hand, and the output side, on the other hand. As no components operating due to gravity are present, the function of the lifting device with the unrolling prevention device is also independent of its installation position.

A further important advantage is furthermore that because of the arrangement of the unrolling prevention device between the output shaft and winding coil, the electric motor itself can also be exchanged under load on the lifting mechanism. Equally, an emergency lowering can be carried out by a direct emergency actuation of the output shaft if the drive fails. The latter is also released by means of the unrolling prevention device according to the invention of the lifting device.

Preferred embodiments of the invention are given in the dependent claims, the features, details and advantages of which are described in more detail in the following description of an embodiment with the aid of the accompanying drawings, in which:

Fig. 1 shows a partially broken away, perspective view of the lifting device,

Fig. 2 shows a vertical rotational axial section of the lifting device according to Fig. 1 and

Figs. 3 and 4 show sections along the section line A-A according to Fig. 2 in different functional positions of the lifting device.

- 4 As emerges from the accompanying drawings, the lifting device designated 1 as a whole is fastened to a solid U-shaped bow 2, which is either stationarily attached to a ceiling of a room or to a travelling trolley of a ceiling rail system. In the case first mentioned, the lifting device 1 is merely used to lift and lower a patient and in the case mentioned second, the patient can additionally be brought to a different location with the aid of the rail system.

The lifting device 1, as the central drive part, has a gear motor 3 with an electrically operated motor unit 4 and an upstream planetary gear 5. The gear motor 3 is flanged to the U-shaped bow 2 laterally on the outside. Its output shaft 6 projects by way of a bore 7 into the interior 8 between the limbs 9, 10 of the bow 2, where the remaining components of the lifting device 1 with the unrolling prevention device are accommodated. A winding coil 11 is thus provided, between the cheeks 12 of which a belt 13 indicated in Fig. 2 layerwise and running out to the bottom can be wound and unwound. The winding coil 11 is rotatably mounted relative to the output shaft 6 by means of ball bearings 14 relative thereto. This winding coil 11 is rigidly connected by one of its cheeks 12 - the right-hand one in relation to Fig. 2 - to an abutment body 15 by means of fixing screws 16, said abutment body being substantially disc-shaped. Three bearing extensions 17, which are rotatably supported at their ends in a pivot bearing 18 in an annular bearing body 19, project in the axially parallel direction from the abutment body 15 from the side remote from the winding coil 11. The bearing body 19 is screwed to the inside of the second limb 10 of the bow 2 opposing the gear motor 3 by means of screws 20. On its side facing the winding coil 11, the bearing body 19 has a projecting annular shoulder that forms a locking ring 21 of the unrolling prevention device in the lifting device 1. The abutment body 15 is arranged radially within this locking ring 21, said abutment body forming, with corresponding recesses, three receivers 22 arranged angle-symmetrically with respect to the rotational axis R of the lifting device, said receivers in each case having, on the inside, wedge faces 23 adopting a large obtuse angle W of about 150° with respect to one another.

- 5 Said wedge faces are symmetrical with respect to a radial line passing through the apex of the angle.

Congruently formed clamping bodies 24, the radially outer side 25 of which is arc of a circle-shaped with an external diameter corresponding to the internal diameter of the locking ring 21, are inserted in the receivers 22, in each case. The two clamping bodies 24 radially inwardly have contact faces 26 in each case, which are at the angle W to one another and cooperate with the wedge faces 23 of the receivers 22 in the abutment body 15 in a manner still to be described in more detail.

The clamping bodies 24 are in each case coupled to the output shaft 6 by means of a coupling arm 27 articulated to the end face of the output shaft 6 by means of pivot bolts 28. The connection between the coupling arm 27 and clamping body 24 takes place here by means of a sliding connection that is radially affected by play, which is realised by a connecting bolt 29 on the side face of the clamping body 24 in a radially directed slot 30 in the coupling arm

27.

Finally, each coupling arm 27 is spring-loaded by paired tension springs 31 clamped between its inner end and the abutment body 15, which will be functionally described in more detail below.

The mode of functioning of the lifting device 1 with an unrolling prevention device is now to be described as follows:

In the locking position of the lifting device shown in Fig. 3, the output shaft 6 is torque-free and, without further securing measures, in the event of a loadinduced counter-torque G, upon the exceeding of the inner inhibition of the gear motor 3, would lead to an uncontrolled unwinding of the belt 13.

In order to prevent this, the lifting device has the unrolling prevention device formed from the abutment body 15, clamping body 24 and locking ring 21. The

- 6 counter-torque G is transmitted by the winding coil 11 to the abutment body 15, which therefore exhibits the tendency to rotate clockwise in relation to Fig. 3. Owing to this introduction of force, the clamping bodies 24 are pressed radially outwardly by means of their contact faces 26 by means of the wedge faces 23 of the receivers 22 in the abutment body 15, so they come into braking engagement with the clamping ring 21 and therefore prevent a further, uncontrolled rotation of the abutment body 15 with the winding coil 11. The coupling arms 27 are therefore radially erected and are symmetrical to a radial line running through the pivot bolts 28. The lifting device 1 is therefore reliably rotationally blocked.

In the event of an actuation of the gear motor 3, for example to lift a load counter to the counter-torque G, the drive torque D produced by the gear motor will ensure a rotation of the output shaft 6 in the anti-clockwise direction in relation to Fig. 4. This rotary movement is transferred to the coupling arms 27, which, figuratively speaking, “bend in” and are drawn radially inwardly by their outer ends. As a result, the connecting bolt 29 in the slot 30 comes to abut the radially outer end thereof. Upon a further rotation of the output shaft 6, the clamping bodies 24 are drawn radially inwardly so they leave the locking position on the locking ring 21. Owing to the abutment of the contact faces 26 of the clamping bodies 24 pointing in the direction of the drive torque D on the corresponding wedge faces of the receivers 22 in the abutment body 15, the latter is entrained in the direction of the drive torque D and the winding body 10 is correspondingly made to carry out the rotary movement. A patient suspended on the belt is thus drawn upwardly.

When the gear motor 3 is switched off, the counter-torque G is active again, so the coupling arms 27 are erected again under the influence of the abutment body 15 on the clamping bodies 24 and the latter are pressed radially outwardly onto the locking ring 21 into the blocking position. Thus the position shown in Fig. 3 is adopted again.

- 7 To let down the patient - as is not shown in more detail in the drawings - the output shaft 6 is made to rotate parallel to the counter-torque G, so the coupling arms 27 “bend in” in the opposite direction in relation to Fig. 4 and thus pull the clamping bodies 24 radially inwardly again. As a result, the rotary blocking of the lifting device 1 is eliminated again and the load can be safely let down under the control of the gear motor 3.

The mentioned tension spring pairs 31 in this case assist the erecting movement of the coupling arms 27 and the aligning connected therewith of the output shaft 6 and abutment body 15 in relation to one another into the blocking position shown in Fig. 3. The interaction between the two rotational directions of the drive torque D to wind and unwind the belt 13 is configured overall in the manner of dead centre kinematics, in which the coupling arms 27 bend in once in the unwinding or winding direction, in other words in opposite directions, depending on the torque direction.

Instead of the planetary gear 5, a spur gear may also be provided for the output shaft 6, the motor unit 4 then not being arranged aligned with the output shaft in the axial direction, but being arranged laterally adjacent thereto with a parallel offset.

Finally, as indicated in Fig. 2, the bow 2 may have a central through-bore 33 in its limb 10 remote from the gear motor 3, by way of which through-bore a tool connection 34 rests on the output shaft 6 in the access region. The tool connection 34 may, for example, be formed by the extended pivot bolts 28, on which a rotary handle with its tool head having three corresponding receiving bores can be placed. Thus, an emergency lowering can take place if the gear motor 3 fails by manual rotation of the output shaft 6 with the aid of this rotary handle.

Because of the mode of construction shown of the lifting device 1, a modular system can advantageously be realised, in that the output shaft 6 can be equipped with the most varied gear motors. Owing to the symmetric

- 8 construction of the lifting device 1, many identical parts are produced here, which involves a small diversity of parts in the construction.

Overall, a very compact, reliably operating lifting device 1 with an unrolling prevention device is provided.

Claims

Patent claims

Lifting device, in particular a patient lifter, comprising

a drive motor (3, 4) with an output shaft (6), and

a winding spool (11) for winding and unwinding a lifting mechanism, in particular a lifting belt (13), characterized by,

- a mounting of the winding coil (11), which can be made to rotate relative to the output shaft (6),

- a system body (15) which is non-rotatably connected to the winding coil (11),

- at least one clamping body (24), which can be displaced radially relative to the output shaft (6) between the inner abutment body (15) and an outer locking ring (21), which clamping body is coupled by means of a coupling arm (27) which is articulated to the output shaft (6), to the latter in such a way that = in case of a torque (D) in the winding direction produced by the output shaft (6), the clamping body (24) can be transferred from its locking position resting on the locking ring (21) to a torque transfer position resting on a wedge surface (23) of the abutment body (15) to cause the abutment body (15) to rotate with the winding coil (11) independently of the load-generated counter-torque (G) acting on the winding coil (11), and = in the case of a torque-free output shaft (6) due to the load-produced counter-torque (G) on the winding coil (11), the at least one clamping body (24) is loaded by means of abutment body ts (15) wedge surface (23) radially outwards and into the locking position resting on the locking ring (21) with rotating blocking of the abutment body (15) with the winding coil (11).

Lifting device according to Claim 1, characterized in that three clamping bodies (24) with respective clamping arms (27) are arranged in receiving devices (22) which form the wedge surfaces (23) in the abutment body (15).

Lifting device according to Claim 1 or 2, characterized in that the clamping bodies (24) with associated coupling arm (27) and receiving device (22) are arranged at an angle symmetrically with respect to the axis of rotation (R) of the output shaft (6).

Lifting device according to one of the preceding claims, characterized in that each clamping body (24) has two contact surfaces (26) which are located at an mutually obtuse angle relative to each other, to the associated wedge surfaces (23) on the abutment body (15). ).

Lifting device according to any one of the preceding claims, characterized in that each coupling arm (27) is coupled to the associated clamping body (24) by means of a displacement connection (29, 30) which is radially actuated by play.

Lifting device according to Claim 5, characterized in that the displacement connection is formed by means of a slotted connection bolt (29) between the clamping body (24) and the coupling arm (27).

Lifting device according to any one of the preceding claims, characterized in that each coupling arm (27) is articulated in a spring-loaded manner with the output shaft (26) in such a way that each coupling arm (27) is raised from a bent position by a torque transmission between the output shaft (6) by means of each clamping body (24) for the abutment body (15) to a raised position in the locking position.

Lifting device according to any one of the preceding claims, characterized in that the drive motor (3) has a transmission gear, in particular a planetary gear (5) or a cylindrical gear transmission.

Lifting device according to any one of the preceding claims, characterized in that the output shaft (6) has a tool connection (34) for a manual emergency lowering.