Cable brake, elevator car and elevator system

Abstract

A cable brake includes a pair of brake shoes having braking surfaces facing one another and between which a brake cable is guided. A first brake shoe is movable between a braking position, pressing the cable against the braking surface of the other brake shoe, and a release position, releasing the cable between the brake shoes. A releasable retaining device retains the first brake shoe in the release position, and/or a reset device switches the first brake shoe from the braking position to the release position. Two rotatably mounted pivot arms connected to the first brake shoe are arranged in a parallelogram with one side oriented in parallel with the cable guidance direction. A switchable electromagnet of the retaining device holds the first brake shoe in the release position. The brake shoes, pivot arms, retaining device and reset device are arranged in a housing connected to an elevator car.

Claims

1. An elevator system including a cable brake and a brake cable, the cable brake having a pair of brake shoes with braking surfaces that face one another, the brake cable being fastened in an elevator shaft and being guided between the braking surfaces, a first of the brake shoes being movable between a braking position, in which the brake cable is pressed against the braking surface of a second of the brake shoes, and a release position, in which the brake cable is released between the brake shoes, the cable brake comprising: two rotatably mounted pivot arms each connected to the first brake shoe and being arranged as a parallelogram, one side of the parallelogram being oriented in parallel with a cable guidance direction of the brake cable; a releasable retaining device that applies a retaining force to the first brake shoe in the release position wherein the retaining force acts on one of the pivot arms; a reset device for switching the first brake shoe from the braking position to the release position; a housing in which the brake shoes, the pivot arms, the retaining device and the reset device are arranged, the housing being connected to an elevator car; wherein the elevator car is guided by hollow rails that are not compression-resistant enough to withstand elevator car braking forces; wherein at least one of the retaining device and the reset device is inactive during braking of the elevator when the brake shoes are in the braking position; and including at least two feed springs arranged in parallel that exert a force on the first brake shoe in a direction of the braking position, the feed springs being tension springs mounted rotatably about an axis arranged in parallel with rotational axes of the pivot arms.

2. The elevator system according to claim 1 wherein the brake shoes, the pivot arms, the retaining device and the reset device are arranged on a common housing plate in the housing.

3. The elevator system according to claim 1 wherein the retaining device includes a switchable electromagnet that holds the first brake shoe in the release position when the electromagnet is supplied with current.

4. The elevator system according to claim 1 wherein the first brake shoe is switched into the release position when the reset device is supplied with current.

5. The elevator system according to claim 1 wherein the reset device includes a switchable stroke magnet arranged to act on one of the pivot arms.

6. The elevator system according to claim 1 wherein the cable brake includes a stop arranged such that at least one of pivot arms abuts and/or the first brake shoe abuts the stop in the braking position.

7. The elevator system according to claim 1 wherein the retaining device and the reset device are coupled together such that the reset device can be activated only when the retaining device is active.

8. The elevator system according to claim 1 wherein the cable brake includes four of the feed springs arranged in parallel.

9. The elevator system according to claim 1 wherein the feed springs are arranged such that, in the release position, they are deflected with respect to a normal to the cable guidance direction at a feed angle and, in the braking position, they are deflected at an angle that is smaller than the feed angle.

10. The elevator system according to claim 1 wherein the cable brake includes an upper pair of guide rollers and a lower pair of guide rollers that align the brake cable with respect to the brake shoes.

11. A method for braking an elevator car using the elevator system according to claim 1, comprising the following steps: releasing the retaining device; moving the first brake shoe from the release position to the braking position whereby the pivot arms change position; and wherein the retaining device is released by interrupting a current supply to an electromagnet holding the first brake shoe in the release position.

12. The elevator system according to claim 1 wherein the reset device acts on the one of the pivot arms acted upon by the retaining device or acts on another of the pivot arms.

13. An elevator system including a cable brake and a brake cable, the cable brake having a pair of brake shoes with braking surfaces that face one another, the brake cable being fastened in an elevator shaft and being guided between the braking surfaces, a first of the brake shoes being movable between a braking position, in which the brake cable is pressed against the braking surface of a second of the brake shoes, and a release position, in which the brake cable is released between the brake shoes, the cable brake comprising: a releasable retaining device that applies a retaining force to the first brake shoe in the release position; two rotatably mounted pivot arms each connected to the first brake shoe and being arranged as a parallelogram, one side of the parallelogram being oriented in parallel with a cable guidance direction of the brake cable; a reset device for switching the first brake shoe from the braking position to the release position wherein the reset device presses on one of the pivot arms; a housing in which the brake shoes, the pivot arms, the retaining device and the reset device are arranged, the housing being connected to an elevator car; wherein the elevator car is guided by hollow rails that are not compression-resistant enough to withstand elevator car braking forces; wherein at least one of the retaining device and the reset device is inactive during braking of the elevator when the brake shoes are in the braking position; and including at least two feed springs arranged in parallel that exert a force on the first brake shoe in a direction of the braking position, the feed springs being tension springs mounted rotatably about an axis arranged in parallel with rotational axes of the pivot arms.

Description

DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention are described in greater detail in the following description with reference to the accompanying drawings, in which similar elements are denoted by the same reference numerals and in which:

(2) FIG. 1 is a side view of a cable brake in the release position;

(3) FIG. 2 is a side view of the cable brake in the braking position;

(4) FIG. 3 is a perspective view of the cable brake in the braking position;

(5) FIG. 4a is a schematic plan view of a first example elevator system;

(6) FIG. 4b is a schematic side view of the first example elevator system;

(7) FIG. 5a is a schematic plan view of a second example elevator system; and

(8) FIG. 5b is a schematic side view of the second example elevator system.

DETAILED DESCRIPTION

(9) FIG. 1 is a side view of a cable brake 1 in the release position. FIGS. 2 and 3 show the same cable brake 1 in the braking position.

(10) The cable brake 1 comprises two brake shoes 2, 3 having braking surfaces 4, 5 that face one another. The brake cable 24 (not shown explicitly in FIG. 1-3; see FIGS. 4a, 4b, 5a and 5b) can be guided between the braking surfaces 4, 5 in a cable guidance direction 6.

(11) A first brake shoe 2 is connected to two rotatably mounted pivot arms 10a, 10b, which are arranged in a parallelogram of which one side, for example the connecting line of the hinge points to the brake shoe 2, is oriented in parallel with the cable guidance direction 6.

(12) By means of the pivot arms 10a, 10b, the first brake shoe 2 can be moved between a braking position, in which the cable is pressed against the braking surface 5 of the other brake shoe 3 (FIG. 2 and FIG. 3), and a release position (FIG. 1), in which there is a sufficiently large distance 27 between the braking surfaces 4, 5 to release the cable.

(13) The cable brake 1 has a releasable retaining device 8, which applies a retaining force to the first brake shoe 2 in the release position. The retaining device 8 comprises a switchable electromagnet 14, which holds the first brake shoe 2 in the release position when supplied with current.

(14) The electromagnet 14 interacts with an armature 28, which is attached to one of the pivot arms 10a and holds the pivot arms 10a, 10b in a deflection angle 33 with respect to a normal 13 to the cable guidance direction 6. As soon as the electromagnet 14 is de-energized, the retaining force is no longer applied and the pivot arms 10a, 10b can change their position. In the braking position, the hinge points of the pivot arms 10a, 10b approximately form a rectangle.

(15) The position change is caused by, for example four, feed springs 19 arranged in parallel with one another. They provide a force in the direction of the braking position. The feed springs 19 are preferably rotatably mounted about an axis 29 arranged in parallel with the rotational axes 30 (FIG. 3) of the pivot arms 10a, 10b.

(16) The feed springs 19 are deflected in the release position with respect to the normal 13 to the cable guidance direction 6 (with respect to the horizontal when in the fitted state) by a feed angle 12a, and are deflected in the braking position by an angle 12b that is smaller than the feed angle 12a. The closure force component of the feed springs 19 is thus smaller in the braking position, in which the frictional force of the cable is active anyway, than in the release position.

(17) By means of a reset device 9, the first brake shoe 2 can be switched from the braking position to the release position. By way of example, the reset device 9 comprises a switchable stroke magnet 15 arranged in particular so as to act on one pivot arm 10a.

(18) Preferably, the electromagnet 14 and the stroke magnet 15 are wired such as to be de-energized in the event of braking.

(19) In addition, the electromagnet 14 and the stroke magnet 15 are coupled such that the stroke magnet 15 is only supplied with current when the electromagnet 14 is supplied with current.

(20) The pivot arms 10a, 10b comprise a spring device 7, which applies a spring force to the first brake shoe 2 in the braking position. For this purpose, each pivot arm 10a, 10b is equipped with at least one brake spring 11 each, for example a pretensionable compression spring, in particular a disk spring or an assembly of disk springs.

(21) The cable brake 1 has a stop 16 arranged such that at least the first brake shoe 2 abuts the stop 16 in the braking position.

(22) The cable brake 1 can comprise a position sensor 34, by means of which it can be detected whether the cable brake 1 is in the braking position. If use of the cable brake is detected by means of the position sensor 34, normal travel of the elevator can be prevented in this case. The position sensor 34 can be designed as a switch that is actuated when a pivot arm 10b strikes the position sensor 34 in the braking position.

(23) The cable brake 1 preferably comprises a housing plate 18, which forms a housing 17 together with a cover (not shown in the figure; see FIGS. 4a, 4b, 5a and 5b). The pivot arms 10a, 10b are hinged to the housing plate, and a brake shoe 3, the retaining device 8, and the reset device 9 are rigidly fitted thereto. In addition, guide rollers 23 for aligning the cable with respect to the brake shoes 2, 3 are attached to the housing plate 18. In the example, the guide rollers 23 are resiliently coupled to the brake shoe 3 by means of spring devices 35 such that the guide rollers 23 can retreat when the brake cable presses against the brake shoe 3.

(24) A mount 31 for securing the feed springs 19 is also provided on the housing plate 18.

(25) FIG. 4a is a schematic plan view of a first example elevator system 25, and FIG. 4b is a schematic side view of the same example elevator system 25.

(26) In an elevator shaft (not shown in more detail), two hollow rails 26 are provided, which are attached to two opposite walls. The hollow rails are used to guide an elevator car 20.

(27) The brake cables 24 are arranged along a diagonal 36 rotated relative to the center line or line of symmetry of the elevator car 32. Accordingly, cable brakes 1 are attached to the elevator car 20. By means of this arrangement, when the elevator car is being braked a guidance force action on the guide rails 26 is minimal.

(28) The cable brakes 1 each comprise a housing 17, which is fastened to a load-bearing structure of the elevator car 20, such as the floor 21 or a supporting frame.

(29) FIG. 5a is a schematic plan view of a second example elevator system 25, and FIG. 5b is a schematic side view of the same example elevator system 25.

(30) In an elevator shaft (not shown in more detail), two hollow rails 26 are provided, which are attached to a wall. The hollow rails 26 are used to guide an elevator car 20, and interact with rail guides 22 attached to the elevator car 20.

(31) The brake cables 24 are arranged on opposite sides of the elevator car 20 on the center line or line of symmetry 32 of the elevator car 20. Accordingly, cable brakes 1 are attached to the elevator car 20. The cable brakes 1 comprise a housing 17, which is fastened to either the floor 21 or a load-bearing structure of the elevator car 20.

(32) The cable brake 1 has a very planar design, and so it has space next to an elevator car 20 even in a narrow elevator shaft.

(33) Typically, the cable brake 1 can be used for brake cables 24 having diameters between 11 and 19 mm. A pair of cable brakes can secure transport loads between 1000 and 2000 kg.

(34) The installation depth is merely approximately four times the cable diameter and crucially is determined by the components used, for example by the diameter of the brake springs 11 or of the electromagnet 15. For example, an installation depth of approximately 50 mm is conceivable for an installation height of more than 500 mm.

(35) 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.