Internal drum brakes in conjunction with elevator drives which are advantageously driven by belts and whose operating elements are mounted outside the drive or brake housing and the braking surfaces are part of the rope pulley or traction sheave

Abstract

1. Internal drum brake in conjunction with elevator drives whose actuating elements are mounted outside the drive housing and the braking surfaces are part of the rope pulley or traction sheave. 2.1 Internal drum brakes become ineffective due to brake fluid if their actuating elements are located between the brake shoes and are under pressure for long periods of time to close. 2.2 In the solution according to the invention, the actuating elements (1 + 6) are mounted outside the drive housing, and a compression spring (7) is used to close the brake. The action of the actuating elements (1 + 6) is preferably transmitted to the linings via a camshaft (3) or a draw key. 2.3 Internal drum brakes for elevator drives with preferably integrated or permanently connected braking surfaces on the traction sheave.

Description

Problem (state of the art)

[0001] Internal drum brakes have inherent advantages over external drum brakes and disc brakes. Their servo action makes them significantly more effective and they possess higher holding forces when stationary. The very low thermal load of elevator brakes, which are primarily used as brakes for stationary applications, means that internal drum brakes do not have any disadvantages compared to external drum or disc brakes. In conjunction with elevator drives, their actuation is located directly between the brake shoes. These are preferably hydraulic. To apply the brake, pressure is applied to these hydraulic cylinders. This moves the pistons apart, pressing the brake shoes against the braking surfaces of the brake drum. This can be a separate drum, or in other designs, this drum or drum surface is part of the traction sheave itself.In any case, the pressure in the cylinder must be high enough for the brake to engage reliably. Since elevators are often subjected to extended downtimes, the system remains in this state; the cylinders are not moved for extended periods and are constantly subjected to high pressure. This leads to fatigue and embrittlement of the piston seals, and subsequently to leaks in the hydraulic cylinder. The resulting brake fluid comes into contact with the brake pads, reducing their frictional performance to the point of ineffectiveness. This condition is extremely detrimental to the safety of the elevator. Repair is very complex, and the defect is very difficult to detect. Inventive solution for internal drum brakes in conjunction with elevator drives which are advantageously driven by belts

[0002] In the inventive solution described below, the actuating elements are arranged outside the drive pulley and the housing wall (1). The linings are actuated via a camshaft (3) or another type of spreading mechanism. If leaks occur in the release device (2), they are easily detectable and the release device can be replaced simply. The camshaft (3) is rotated via the locking device (6) and its closing spring (7) via the lever (4) so ​​that the cams (8) press the inner brake linings (5) against the braking surfaces, thus closing the brake and making it effective. The release unit (2) moves the camshaft (3) back against the spring force and thus releases the brake. The release device can be actuated hydraulically (2), mechanically, electromechanically (14) or in another way.An advantageous solution is the separation of the locking unit (7) and the release mechanism (2 / 14). This allows the locking or compression spring (7) to be replaced with very little effort, or to use different springs that enable different braking effects. Another solution combines the locking unit and the release mechanism into a single component. The disadvantage is the very complex and costly replacement or exchange of components.

[0003] Another solution is the use of an expanding wedge (13). This is pulled by a compression spring (7) preferably towards the housing wall (1). This moves the inner brake shoes (5) apart, brings them into contact and generates the braking effect. If the wedge, as shown in Fig. 2, the electromagnet (14) is energized, it pulls the tie rod (15) into the coil (14) and thus releases the brake (5) Fig. 2). Instead of the electromagnet, another release mechanism can be used, for example, a hydraulic system. In this case, it is advantageous to position the hydraulic cylinder at the end of the release unit and the compression spring (7) towards the housing wall (1). In all solutions, it is advantageous to use a compression spring to apply the brake. This guarantees that the elevator comes to a standstill in the event of a failure of an electrical, hydraulic, or other system. When using the expanding wedge (13), it is advantageous to design it so that, after the compression spring and release unit have been removed, it can be removed by rotating it 90 degrees through the appropriately designed housing opening. The brake pads (5) are spread with the aid of an external assembly aid.

[0004] To ensure redundancy of the system, it is mounted on both sides of the drive. List of reference symbols Fig. 1 1 Housing wall drive / brake housing 2 release device (here hydraulic) 3 camshaft 4 levers 5 inner brake shoes 6 Shooting element with compression spring 7 compression spring 9 support bearings for brake pads 10 camshaft bearings Fig. 2 1 Housing wall drive / (or housing wall or brake housing) 2 release device (here hydraulic) 3 camshaft 5 inner brake shoes 6 Shooting element with compression spring 7 compression spring 8 cams 11 Traction sheave rope area (traction sheave in partial view) Fig. 3 1 housing wall drive 2 release device 4 levers 5 inner brake shoes 6 Shooting element 8 cams 11 Traction sheave rope area (traction sheave in partial view) 12 Drive pulley belt area (drive pulley in partial view) Fig. 4 Brake released Solenoid coil energized Magnet armature pulled Expanding wedge pressed and Fig. 5 Brake closed Solenoid coil de-energized Magnet armature free Expanding wedge pulled 1 housing wall drive 5 inner brake shoes 7 compression spring 13 Expanding wedge 14 Solenoid coil 15 tie rods 16 Housing for solenoid coil 18 Brake pad wedge surface 19 compression spring plate 20 Connecting element: compression spring plate (19) tie rod (15) expanding wedge (13)

Claims

[1] Internal drum brake preferably in conjunction with elevator drives characterized by that it has external actuating elements and the drive pulley of the drive is preferably driven by belts and the braking surfaces are a fixed or firmly connected part of the drive pulley. [2] Internal drum brake in conjunction with elevator drives according to claim 1 characterized by that the actuating elements are located wholly or partly outside the drive or brake housing and preferably act on the brake pads via a camshaft, an expanding wedge or another type of expanding device. [3] Internal drum brake in conjunction with elevator drives according to claim 1 characterized by that one of the actuating elements is a compression spring system that closes the brake. [4] Internal drum brake in conjunction with elevator drives according to one of the preceding claims characterized bythat the drive pulley is preferably driven by belts. [5] Internal drum brake in conjunction with elevator drives according to claim 4 characterized by that the belt ratio is multiple. [6] Internal drum brake in conjunction with elevator drives according to claim 1 characterized by that the release element is of hydraulic, mechanical or electromechanical type or is designed as a combination. [7] Internal drum brake in conjunction with elevator drives according to claims 3 and 6 characterized by that the release element and the locking element form a unit.

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