Safety brake for a travel body of an elevator system

Abstract

A safety brake for an elevator system having at least one traveling body movable in an elevator shaft along a guide rail and/or a brake rail. The safety brake is suitable for braking and retaining the traveling body on the guide and/or brake rail as required. The safety brake includes a control plate for receiving a brake body and for positioning the brake body relative to the guide and/or brake rail. The brake body is designed in at least two pieces and includes a first brake element and a second brake element. The first brake element is solely for braking and retaining purposes when the traveling body is moving along the guide and/or brake rail in an upward direction, and the second brake element is solely for braking and retaining purposes when the traveling body is moving along the guide and/or the brake rail in a downward direction.

Claims

1. A safety brake for an elevator installation with at least one travel body movable along at least one of a guide rail and a brake rail in an elevator shaft, wherein the safety brake brakes and holds the travel body at the rail when required, the safety brake comprising: a brake body having a first brake element and a second brake element, wherein the first and second brake elements are movable independently of one another, the first brake element and the second brake element are pivotable in opposite directions about a common axle, and the first brake element is substantially for braking and holding only in case of movement of the travel body along the rail in an upward direction and wherein the second brake element is for braking and fixing only in case of movement of the travel body along the rail in a downward direction; and a control plate for positioning the brake body relative to the guide wherein the first and second brake elements are adjustable together relative to the rail to simultaneously bring the first brake element and the second brake element into contact with the guide rail, wherein the control plate is positionable in each of a rest position and a braking position by a linear movement relative to the rail.

2. The safety brake according to claim 1 wherein the control plate is held in the rest position by an electromagnet that is switched on by being provided with electric power, and wherein the electromagnet is switched off by not being provided with electric power to enable the control plate to move into the braking position by a compression spring.

3. The safety brake according to claim 1 wherein at least one of the first brake element and the second brake element is pivotably arranged on the axle at a support of the safety brake and the control plate is arranged at the support to be linearly movable or pivotably movable to position the at least one of the first brake element and the second brake element relative to the rail.

4. The safety brake according to claim 3 wherein the first brake element and the second brake element are pivotable at the same time by the control plate to pivot from a basic position out of contact with the rail to a first braking position in contact with the rail.

5. The safety brake according to claim 4 wherein the at least one of the first brake element and the second brake element is pivotable by friction locking with the rail from the first braking position to a second braking position.

6. The safety brake according to claim 5 wherein the control plate is movable from the braking position to the rest position by pivotation of the at least one of the first brake element and the second brake element from the first braking position to the second braking position.

7. The safety brake according to claim 1 wherein at least one of the first brake element and the second brake element is formed as an eccentric disc.

8. The safety brake according to claim 7 wherein the eccentric disc is curved in a section in contact with the rail in a first braking position, and the eccentric disc is planar in a section in contact with the rail in a second braking position.

9. The safety brake according to claim 8 wherein a side of the eccentric disc remote from the rail is configured such that through pivotation of the eccentric disc, from the first braking position to the second braking position, a reset force is exerted on the control plate by the side of the eccentric disc to move the control plate into the rest position.

10. The safety brake according to claim 8 wherein the control plate has a contact surface whereby on movement of the control plate into the first braking position the eccentric disc is pivoted into the first braking position by interaction with the contact surface and a restoring force is exerted on the control plate on pivotation of the eccentric disc into the second braking position.

11. The safety brake according to claim 1 wherein a first braking area of the first brake element is smaller than a second braking area of the second brake element.

12. The safety brake according to claim 11 wherein the first braking area is at most 75% of the second braking area.

13. The safety brake according to claim 11 wherein the first braking area is at most 60% of the second braking area.

14. The safety brake according to claim 1 wherein the second brake element has two eccentric discs with substantially a same braking area, wherein the first brake element has a first braking area substantially equal to the braking area of one of the eccentric discs, and wherein the first brake element is arranged between the two eccentric discs of the second brake element.

15. The safety brake according to claim 1 including a sensor for at least one of position monitoring and state monitoring of at least one of the first brake element, the second brake element and the control plate.

16. The safety brake according to claim 1 wherein at least one of the first brake element and the second brake element is biased in a direction of the control plate by at least one spring.

17. An elevator installation having a travel body and a safety brake according to claim 1 arranged at the travel body.

18. A method for braking and holding a travel body of an elevator installation with a safety brake when required, wherein the safety brake includes a control plate for positioning an at least two-part brake body relative to at least one of a guide rail and a brake rail, the method comprising the steps of: adjusting a first brake element and a second brake element of the brake body relative to the rail by moving the control plate relative to the rail to bring the first and second brake elements into a first braking position, and thereby simultaneously bringing the first brake element and the second brake element in contact with at least one of the guide rail and the brake rail, wherein the first brake element and the second brake element are pivotable in opposite directions about a common axle; and moving the travel body along the rail in an upward direction to bring the first brake element independently of the second brake element from the first braking position into a second braking position, or moving the travel body along the rail in a downward direction to bring the second brake element independently of the first brake element from the first braking position into the second braking position.

Description

DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention are explained in more detail in the following by way of embodiments for better understanding and without restricting the invention to the embodiments, wherein:

(2) FIG. 1 shows a schematic illustration of an elevator installation with a safety brake according to the invention;

(3) FIGS. 2 to 7 show schematic illustrations of a safety brake according to the invention in sequential operational states; and

(4) FIG. 8 shows a sectional side view of a brake body of the safety brake according to the invention.

DETAILED DESCRIPTION

(5) An elevator installation 2 with a travel body 3 comprising a safety brake 1 according to the invention for braking and fixing the travel body 3 when required is shown in FIG. 1 in schematic illustration.

(6) The elevator installation 2 comprises an elevator shaft 5 in which a guide rail 4 is arranged, along which the travel body 3 is movable in an upward direction a or a downward direction b. The travel body 3 is suspended in the elevator shaft 5 by means of support equipment 16 formed by cables. Movement of the travel body 3 in the upward direction a and/or the downward direction b is possible by means of a drive 15, which is in operative connection with the travel body 3 by way of the support equipment 16. In the case of the illustrated elevator installation 2 the travel body 3, frequently an elevator car, is supported to the full extent by the drive 15. As a rule, a further travel body, in the form of a counterweight, is disposed in the elevator shaft, which moves oppositely to the travel body 3 and which is correspondingly fastened to the opposite end of the support equipment 16.

(7) The safety brake 1 mounted on the travel body 3 is constructed so that when required, such as, for example, a failure of the support equipment 16 or in the case of power failure, the travel body can be braked and fixed. For this purpose a braking action is achieved by the safety brake 1 in interaction with the guide rail 4. The guide rail 4 can, in a given case, also be constructed as a brake rail.

(8) Alternatively, the arrangement of a brake rail additionally to the guide rail is also conceivable in order to, for example, brake the travel body 3 only in specific sections in the elevator shaft 5 by means of the safety brake 1.

(9) A sensor 12 for position monitoring and/or state monitoring of the safety brake 1 is arranged at the safety brake 1. The braking action of the safety brake 1 can, for example, be compared by the sensor 12 with a target value, whereby a state monitoring of the safety brake can be achieved. The sensor 12 can obviously also be arranged at a different location on the travel body. The sensor 12 can also be merely a switching element which monitors a working setting of the safety brake and, for example, stops the elevator installation if the safety brake is actuated.

(10) From here on and in the following, the same reference numerals are used for the same features in all figures and accordingly are explained again only when required.

(11) A side view of the safety brake 1 according to the invention is schematically illustrated in FIGS. 2 to 7 in sequentially successive operational states. For better understanding, the safety brake 1 is illustrated in co-operation with the guide rail 4, although the guide rail 4 is not a component of the safety brake 1.

(12) The safety brake 1 comprises a support 22. The support 22 forms a housing-like load-bearing structure for absorption of clamping forces of the safety brake device. An axle 9 is fixedly arranged in the support 22. In addition, the safety brake 1 includes a two-level brake body, comprising a first brake element 7 and a second brake element 8. The two brake elements are constructed as eccentric discs and pivotably arranged on the common axle 9. A control plate 6 is arranged in or at the support 22 to be displaceable between a rest position r (FIG. 2) and a braking position e (FIG. 3). The control plate 6 has a surface 19 (FIG. 4) as an outer contact area. The surface 19 interacts with the brake elements 7, 8. In addition, an electromagnet 17 and compression springs 18 are arranged in the support 22. The electromagnet 17 holds the control plate 6 in the rest position r against a force of the compression springs 18. Moreover, a spring 23 resiliently draws the second brake element 8 against the control plate 6 or against the surface 19 of the control plate 6. The second brake element 8 is thus disposed in the basic position g (FIG. 2). Analogously, the first brake element 7 is held by a spring (not illustrated) in the basic position g.

(13) A counter-braking body 13 is arranged on or in the support 22 on the side of the guide rail 4 remote from the first and second brake elements 7, 8. The counter-braking body 13 is supported in the support 22 by means of plate springs 14 and can be pressed against the guide rail 4 so that a braking action is achievable by the safety brake 1. A pressing force of the brake body 13 against the guide rail 4 is settable by, for example, selection of the bias of the plate springs.

(14) The first brake element 7 has a first braking area 10 and is disposed in the basic position g. The second brake element 8 has a second braking area 11 and is similarly disposed in the basic position g. The braking area 11 is larger than the braking area 10, which, however, is not evident in FIGS. 2 to 6.

(15) The arrow denoted by b characterizes the relative movement between the travel body, at which the safety brake 1 is arranged, and the guide rail 4. The travel body is moved in downward direction b, which is illustrated in FIGS. 2 to 6 as movement of the guide rail 4. Thus, a co-ordinate system fixed relative to the safety brake 1 has been selected.

(16) The control plate 6 is disposed in FIG. 2 in the rest position r and is held by means of the electromagnet 17, which can be switched off, in the rest position r. In addition, arranged at the control plate 6 are the compression springs 18 by means of which after switching-off of the electromagnet 17 the control plate 6 is movable into a braking position s (FIG. 3). The braking elements 7, 8 and also the counter-braking body 13 have a gap relative to the guide rail 4 so that the travel body is freely movable along the guide rails.

(17) The safety brake 1 is illustrated in FIG. 3 in a first operating state in which the electromagnet 17 is switched off and the control plate 6 has been brought by means of the compression springs 18 into the braking position e. Through co-operation of the wedge-shaped surface sections of the surface 19 of the control plate 6 and a rear-side shape of the first brake element 7 and the second brake element 8 the two brake elements 7, 8 are pivoted in opposite directions about the axle 9. A respective curved region of each of the brake elements 7, 8, which are constructed as eccentric discs, is thereby brought into contact with the guide rail 4. The two brake elements 7, 8 are now disposed in a first braking position s. They are pressed against the guide rails by a pressing force determined by the compression springs 18.

(18) As illustrated in FIG. 4, one of the two brake elements 7, 8 is further pivoted through the contact between guide rail 4 and two brake elements 7, 8 by means of friction couple by way of the relative movement of the guide rail 4. In the example, depending on the direction of the relative movement the second brake element 8 is further pivoted. In that case due to the shape of the brake elements similar to eccentrics the first brake element 7 loses contact with the guide rail 4 and it is drawn back by its spring (not illustrated) towards the control plate. Due to the shape and arrangement of the second brake element 8 and the surface 19 of the control plate 6 the control plate 6 is simultaneously moved back in direction u into the rest position e.

(19) In FIG. 5 the pivotation of the second brake element into a second braking position z is concluded, whereby the second braking area 11 has been brought into contact with the guide rail 4. The brake element 8 has during the clamping in the second braking position z drawn the support 22 together with the counter-braking lining 13 towards the guide rail and stressed the plate springs 14 so that a desired braking force could be built up. The brake elements 7, 8 are preferably provided with end abutments relative to the support 22 so that further rotation of the brake elements 7, 8 on reaching the second braking position z is prevented.

(20) In addition, during the clamping of the second brake element 8 in the second braking position z the control plate 6 was moved into the rest position r and is again in contact with the electromagnet 17. The compression springs 18 are biased again. The electromagnet 17 is arranged to be yielding substantially parallel to the action of the restoring force u so that bridging-over is made possible in order to guarantee contact between control plate 6 and electromagnet 17 during resetting.

(21) As illustrated in FIG. 6, after braking or fixing of the travel body by means of the safety brake 1 the travel body is moved in an upward direction a, which is also here illustrated by a movement of the guide rail 4. As a result, resetting of the second brake element 8 into the first brake position s and thus release of the safety brake 1 take place. The electromagnet 17 is switched on at the latest on reaching the first braking position s or, better, already beforehand so as to hold the control plate in the rest position r.

(22) As illustrated in FIG. 7, the second braking element 8 is pivoted back into the basic position g, which can be achieved by the spring 23. The safety brake is again reset into its original position in correspondence with FIG. 2.

(23) A detail of the safety brake 1 is illustrated in FIG. 8 in a sectional illustration through the axle. The axle 9 is executed as a component of the support 22. In addition, the first brake element 7 and the second brake element 8 are again arranged at the axle 9. The two brake elements 7, 8 are mounted, multi-level, on the axle 9 by means of a fastening disc 21. The first brake element 7 has a first braking area 10, which is approximately 50% of the second braking area 11 of the second brake element 8. The first brake element 7 is arranged between the two brake parts of the second brake element 8. The brake parts all have a thickness w of 9 to 12 millimeters. The axle 9 is dimensioned in order to take over the clamping forces arising on clamping of the brake element 7, 8 in the second braking position.

(24) The safety brake 1 additionally comprises slide bearings 20, by means of which the brake elements are pivotable as described in the foregoing.

(25) In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.