US1746372A

US1746372A - Elevator brake

Info

Publication number: US1746372A
Application number: US95152A
Authority: US
Inventors: Turnbull William Gordon; Crane Harold Creighton
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-03-16
Filing date: 1926-03-16
Publication date: 1930-02-11
Anticipated expiration: 1947-02-11

Description

F 1930- w. G. TURNBULL ET AL ELEVATOR BRAKE Filed March 16. 1926 Inventors Will/am G. Tar/76. Ham/d 6'. Chime.

' Patented- Feb; 11', 1930 PATENT OFFICEU' WILLIAM eoimon 'rUmuLL AND HAROLD CBEIGHTON CRANE, OI TORONTO ONTARIO, CANADA.

- ELEVATOR BRAKE Application flied March 16,1926. Serial in. 95,152. A

The princi al' object of this invention is, to increase t e operatin efliciency of high speed elevators by provi ing means separate from-the arresting and holding brake which Y will effectively slowdown the movement of the elevator car to the ordinary brake.

The principal feature of the invention consists in the arrangement in connection with an elevator driving mechanism, of a supplementary braking device which will appl the maximumtorque to the driving shat when the elevator is in motion and gradually 1 reduce the torque as the speed of the mechanism decreases.

In the drawin s, Figure 1 is a plan view of an elevator riving unit equipped with our improved brakin device.

Figure 2 is a side e evational view in part mid-section.

' Figure 3 is a transverse section on the line 3--3 of Figure 1 showing a portion of the hydraulic brake casing broken away. 5' In the operation of electrically driven high speed elevators with a single speed drive, the ordinary friction brake is subjected to very heavy stresses and it'is diflicult to efi'ect accurate landin s.

This invention has been devised to relieve the stress on the ordinary braking apparatus by exerting a retarding torque which will effectively. slow down the operation of the mechanism prior to the application of the stopping brake thus effecting a positive low speed from which accurate landings with smooth stops may be made.

In'the accompanying drawings, the assembly illustrated is that of a standard type 40 of drive having the cable sheave 1 operated by a'worm on the motor shaft 2.

A standard friction brake 3 is applied to the motor shaft, being electrically governed from the control mechanism in the car in the usual manner.

The supplementary brake herein illustrated consists of a drum 4 rotatably mounted upon the shaft? and enclosing a rotor memher 5 which is keyed to the motor shaft.

The rotor is provided with a plurality of facilitate the making of accurate landings and reduce the stress on;

radial arms 6 preferably arranged in pairs and between these arms are arranged a plurality of radial arms 7 secured to and extending inwardly from the drum 4.

The periphery of the drum' 4 rotates between the brake shoes 8..which are of the same type as applied to-the brake 3.

This drum 4 is filled with oil or. other suitable fluid and when the brake shoes-8 are out of engagement with the drum 4, said drum rotates with the rotor and the shaft.

Immediately upon the application of the brakes 8 to grip the drum 4 and retard its rotation a resistance ensues' between the

radial arms

6 and 7 through the fluid medium within the drum causing a reacting torque between the rotor and the drum which Varies in directrelation to their relative speed, de-

veloping the maximum torque at the maxii mum motor speed with the drum at. rest.

It will be understood of course that the construction of the rotor and the enclosing drum may be varied, very considerably as may also various other features of construction without departing from the essential feature of the invention.

When the elevator is being operated at high speed both the special hydraulic brake herein described and the friction brake are released and the drum-4 will acquire a speed so slightly less than the motor speed. The slip between the drum and rotor is just suflicient to develop torque enoughto overcome bearing friction and windage of the member 4.

When it is desired to bring the elevator to a stop the shoes 8 of the brake 4- are first applied and as soon as the drum is brought to rest the maximum kinetic energy of the moving mechanism is opposed to the resistancev of the drum with its impeding vanes retarding the movement of the fluid in the drum. The maximum torque is then developed and the speed of the mechanism decreases. The retardation decreases until such a speed is reached'that the torque developed between the rotor and the drum is just suflicient to balance the net torque due to the motor and load. The arresting brake may be applied at any desirable period in the slowing down of the mechanism but by reason of the initial slow down the stop will be quite the rotor through the arresting of said latsmooth and as the stress on the arresting ter rotative member. brake is light an accurate stop may be made. I 5. In an elevator brake, the combination \Vith a slow-down type of brake such as dewith the motor shaft driven in both direc- U scribed, it is possible to operate the elevator tlons and a frlction brake thereon, of arotor Ma slow speed, such as for inching at landfixed to the shaft and having radial vanes, ings.. To utilize the device in this manner a drum rotatably mounted on the shaft and the usual friction brake is released and power enclosing said rotor and being normally free is applied to the motor with the drum 4 to rotate therewith in the same direction,

10 held from rotation. The ultimate speed of sald drum having radial vanes arranged adjathe motor and therefore the elevator is precent to the radial vanes of the rotor, a fluid determined at a limited low value by the remedium enclosed in said drum, and braking sistance of the fluid within the drum. means for arresting the drum against its nor- It will be readily understood that a retardmal rotation with the shaft.

ing brake such as described will be extremely WILLIAM GORDON TURNBULL.

applicable to elevator control as the kinetic HAROLD CREIGHTON CRANE.

energy of the elevator movement varies as the square of the speed and the'torque of the hydraulic brake also varies as the square 20 of the speed. l

' What we claim as our invention is:

1. In an elevator brake, the combination with the means for driving an elevator operating mechanism in both directions and an 25 arresting brake therefor, of a supplementary brake applied to said mechanism'adapted to develop a torque in either direction of rotation which diminishes as the speed of the elevator mechanism decreases.

so 2. In an elevator brake, the combination with the means for driving an elevator 0 erating mechanism in both directions an an arresting brake therefor, of a mechanical- 'ly controlled fluid-impeded supplementary a5 braking means adapted when controlled to automatically oppose the movement of said elevator operating mechanism in either direction with an intensity relative to the speed of travel ofsaid elevator to de-celerate the 40 same independent of the arresting brake.

3. In an elevator brake, the combination withthe elevator drivingmechanism and a mechanical brake therefor, of a supplementary brake member adapted to normally ro- 45 tate with said driving mechanism in either 11 direction, fluid means interposed between said driving means and said supplementary brake member and normally eifecting a driving connection between the two to rotate the 50 supplementary brake member With the driv- 116 ing means, and means for arresting the normal rotation of said supplementary ,brake member to effect a retarding action on said driving mechanism through the fluid means interposed therebetween.

4. In an elevator brake, the combination with the means for driving an elevator mechanism in both directions and an arresting 60 brake, of a rotor operatively connected with the driving mechanism, a member adapted to normally rotate freely with said rotor in either, direction, means for arresting the movement of the latter rotative member, and

65 means for eflectihg a retarding influence on