US1577999A - Elevator braking system - Google Patents

Description

Marh 23 1926.

' W. S. ATKJNSON ELEVATOR BRAKING SYSTE M Filed Oct. 17, 1924 Patented Mar. 23, 1926.

UNETED S'IATESv PATENT OFFICE.

WILLARD S. ATKINSON, OF ASI-ILAND, NEW' JERSEY, ASSIGNOR TO ATLANTIC ELEVA- TOR COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

ELEVATOR BRAKING SYSTEM.

Application filed October 17, 1924. Serial No. 744,109.

To all whom it may concern:

Be it known that l, \VILLARD S. ATKIN- SON, a citizen of the United States, residing in Ashland, county of Camden, State of New Jersey, have invented certain new and useful lmproven'ients in'lfilevator Braking lication.

lily invention relates to a system of brak nism changes from maximum to minimum,

or vice versa, and thereby decrease the rate of change of speed.

In accordance with my invention, a plurality of cumulatively acting brakes are applied or released in succession to effect smooth, gradual or prolonged change of speed either in starting or stopping the ele vator or analogous mechanism. accordance with my invention, the several brakes are actuated or controlled by solenoids, electro-magnets or equivalent, either energized or deenergized simultaneously but operating at different rates or energized or deenergized in succession, to effect setting or litting of the brakes in succession.

Further in accordance with my invention, there is utilized for operating the elevator or the like an alternating current motor of a type effecting little or no electro-dynainic braking, in association with electro-magnetic means or equivalent energized or deenergized simultaneously but operating at different rates or energized or deenergized in succession, to effect smooth, gradual or prolonged change in speed at starting or stopping.

My invention resides in the system, mechanism and features hereinafter described and claimed.

For an understanding of my invention and t'or an illustration of some of the various forms my apparatus may take, reference is to be had to the accompanying drawing, in which:

F 1 is an elevational view oi braking mechanism in accordance with my invention in association with a diagrammatic view of electrical circuits.

Svsteins of which the followin is a s ec1- Further in Fig. 2 is a section, partlyin elevation, on i the line 22-ot' Fig. 1.

Fig. 3 is an elevational view of a modified form of my mechanism, in association with a diagrammatic view of electrical circuits.

Referring to the drawing, D represents the brake drum or equivalent of an elevator mechanism used in hoisting or r'aisingand lowering freight or passenger elevator cars or other loads. (lo-acting with the member D are the brake shoes B, B provided with the brake linings aand a respectively, and pivoted respectively at b and b to the arms c. and c pivoted in turn at d and (P, respectively, to" a fixed member 6. and extending through the members 0 and 0 are the adjusting pins or bolts f which confine or limit the angular movements of the brake shoes upon their pivots b.

Carried by the fixed memberc is the up wardly extending arm or bracket 9 carrying at its upper end the pivot pin or bolt h and having thedownwardly extending lug 2'.

Pivoted independently of each other upon the pin it are the lever arms L and L having pivoted thereto the interiorly threaded nuts or pins j, j respectively, into which are threaded, respectively, the rods 712,70 pivoted at the1r outer endsat m, m respectively, to the aforesaid arms 0 and 0 provided,

respectively, with the recesses 12, 71 against whose bottoms engage the springs 0, 0 respectively, whose other ends engage, respectively, the collars 1), p confined by the nuts or heads q, "9 respectively, upon the rods 1, r extending freely through the arms 0, 0 and secured, respectively, at their inner ends to the aforesaid lug 2'. H c

Pivoted to the lever arms L, L at 8, 8

respectively, are the connecting rods t, F,

pivoted at u, a to the cores or armatures C, C of solenoids or electro-magnets whose energizing windings are indicated at W The springs 0 and 0 operate to set the brake shoes B, B against the drum D, and the solenoids or electro-magnets W, V when energized move the levers Land L in counterclockwise and clockwise directions, respectively, to actuate the arms 0, 0 in counterclockwise and clockwise directions,

respectively, about their pivots (Z, (Z to lift the brake shoes B, B from the drum D in opposition to the springs 0,- 0 and upon deenergization of the solenoids the springs set the brake shoes against the drum.

Carried by A three phase alternating current supply circuit is represented by the conductors 1, 2 and 3 leading to one set of contacts of the switch comprising the movable switch members 1, 5 and 6, of which 4 connects with one terminal of the three phase alternating cur rent motor M, such as an induction motor, or the like. The switch member 5 connects with the contacts 7 and 8 and switch member 6 connects with contacts 9 and 10. Co-- acting with the pair of contacts 7 and 9 are the switch members 11 and 12, whereby the conductors lt and 13, connecting with the remaining terminals of the motor M, with the terminals of the winding N and with the terminals of the winding of the relay R, may be brought into communication with the line conductors 2 and 3, respectively. Similarly, there co-act with the pair of contacts 8 and 10 the switch members 15 and 16 connecting, respectively, with conductor; 13 and 14, whereby they may be brought respectively into comn'iunication with the aforesaid conductors 2 and Accordingly, the switches 11, 12 and 15, 16 constitute reversing switches for reversing the direction of rotation of the motor M. These switches are never simultaneously closed, but may be operated manually, or electromagnetic-ally under control of a switch on the elevator car, as well understood in the art, to cause energization of the motor hi and its rotation in one or the other direction.

The windings W and R are energized every time either of the switches 11, 12 or 1.5, 16 is closed.

Carried by the arnature or core 1'? of the relay R is the member 18 carrying the con tacts 19 and 20, which are adapted to engage and bridge the stationary relay contacts 21 and 22, upon energization of the winding R, which causes the upward movement or the member 18 in opposition to the spring 23. The contact 22 is connected to the conductor 13 and contact 21 is connected with one terminal of the winding W whose other ter minal connects with the conductor 14, whereby when the contacts 21 and 22 are bridged by the member 18 the winding W is energized, drawing its core C downwardly and thereby lifting the brake shoe B in opposition to spring 0 Attached to the armature or core 17 of the relay R is the piston 2 closely fitting and movable longitudinally in the stationary cylinder 25 and having the restricted port 26 for retarding movement of the member 18, both upwardly and downwardly.

When either of the switches 11, 12, or 15, 16 is closed, the windings XV and R- will be energized, causing quite prompt lifting of the brake shoe 8 but dela ed rise of the I I I bridging member 18 and therefore delayed energization oi the winding w and therefore delayed hit-mg of the brake shoe B Accordingly, the brake shoe B is lifted after the brake shoe 13. Upon opening the switch which caused the energization of the winding VI and relay R the spring 23 will force the member 18 downwardly, but this motion is again retarded by the dash pot 24, 25, or equivalent retarding means, and accordingly the winding \V will be deenergized before the winding, W and in consequence the brake shoe B, will be set or applied to the drum 1) in advance of the shoe B The timing effected by the dash pot or equivalent, and by'the length of the contacts .21, 22 may be made. anything suitable or desirable, but in general, is such that the brake shoes B and B are either lifted or set several seconds apart, as, for example, two or three seconds apart, or more or less.

Referring to Fig.- 3, one of the electromagnets or solenoids, as 1V is provided with any suitable means for retarding movement of its core, asc and therefore of the brake shoe B controlled thereby. In the example illustrated, the retarding means takes the form of a dash pot comprising a piston 2 1 secured to the rod t in turn secured to the core C or secured to the lever L or any suitable element in the train of mechanism, and the cylinder 25?, the piston being provided with a restricted orifice 26 causing retardation of movement in both directions.

In this case both windings W, V are si inultaneously energized and deenergized upon closure and opening of either of the switches 11, 12 or 15, 16.

The operation is similar to that previous ly described in connection with Fig. 1, in that the setting and lifting of the brake shoe B? is delayed with respect to the set ting and lifting of the shoe B.

My invention is of particular advantage when the driving motor, as M, is of the alternating current type, with which regenerative braking, sometimes utilized in connection with direct current motors, is either impossible or unsatisfactory. It will be understood, however, that my invention is also applicable in case the driving motor is of the direct current type, especially when not utilized for regenerative or electro-dynamic braking, though where regenerative or electro-dynamic braking is utilized, with either direct or alternating cnrrent motors, my invention may also be used with advantage.

In accoreance with my invention, the acceleration is controlled by the mechanical or friction brakes alone or in association with the electro-dynai'nic or other braking. By my mechanism the acceleration is gradual or prolonged, both when the car or elevator mechanism is starting and stopping. My mechanism is particularly of advantage for the negative acceleration or stopping. In stopping, when the motor is deenergized,

first one brake shoe is applied and some time thereafter the second, with the result that the kinetic energy or momentum of the sys tem is first decreased by one brake shoe,

which does not bring the apparatus to rest,-

and later additionally by the second brake shoe which, acting cumulatively with the first applied brake shoe, brings the system or mechanism to rest without shock or suddenness, and assists in causing the car accurately to register with or find floor levels.

In starting, the acceleration is again graduated or prolonged, first by raising one brake shoe and an appreciable time there-. after the other, with the result that after lifting of the first brake shoe the motor may start the mechanism, but the motion is resisted by the second brake shoe until it is lifted.

In starting a car downwardly,,particularly when loaded, the tendency is immediately or quickly to attain considerable or high velocity, the motor in such case starting without substantial load upon itself, and itself in no way or but slightly retarding the car and its load. This mode of op eration is improved, however, in accordance with my invention, since when the first brake shoe is lifted, the second is not alone able to hold the car and its load against movement, but allows thebrake drum to slip and to some extent throw a load upon the motor. Upon lifting of the second shoe the speed increases to normal descending speed.

What Iclaim is: i

1. The method of controlling the acceleration of elevator mechanism provided with driving mechanism and-a plurality of brake mechanisms, which comprises operating one of said brake mechanisms'with respect to a brake drum and after a period of time operating another of said brake mechanisms with respect to the same drum to graduate and prolong the acceleration.

2. The method of controlling the negativ acceleration of elevator mechanism provided with driving mechanism and a plurality of braking mechanisms, which comprises operating one of said brake mechanisms with respect to a brake drum to apply a braking effect, and after a period of time operating another of said brake mechanisms with respect to the same drum to apply a cumulatively acting braking effect to graduate and prolong the acceleration.

3. The method of positively accelerating elevator mechanism provided with driving mechanism and a plurality of brake mechanisms operating cumulatively on a brake drum to hold said elevator mechanism at rest, which comprises operating one of said brakemechanisms with respect to said drum to reduce the total braking effect, and after a period of'time operating another of said brake mechanisms with respect to said drum further to reduce the braking effect to prolong the period during Whichthe total braking effect is reduced- 4. The method of operating elevator mechanism provided with an electric driving motor and brake mechanisms, which comprises deenergizing the electric motor,

and operating said brake mechanismsat times differing from each other for producing a graduated negative acceleration of said elevator mechanism.

5; The method of operating elevator mechanism provided with an'electric driving motor and brake mechanisms, Which comprises deenergizing the electric motor and substantially simultaneously operating one of said brake mechanisms to produce a brak ing effect, and thereafter operating another of said brake mechanisms, to prolong the negative acceleration of said elevator mechanism.

6. The method of operating elevator mechanism provided with an electric driving motor and brake mechanisms, which comprises energizing the electric motor, and operating said brake mechanisms at times differing from each other for producing a graduated positive acceleration of said elevator mechanism.

'7. The method of operating elevator mechanism provided with an electric drivin motor and brake mechanisms, Which comprises energizing the electric motor and substantially simultaneously -operating one of said brake mechanismsto reduce the braking effect upon said'elevator mechanism, and thereafter operating another of said brake 'mechanisms further to reduce the braking effect upon said elevator mechanism, to pro long the positive acceleration of said elevator mechanism. v

8. The combination with an elevator mechanism,of a brake drum and a plurality of brake mechanisms therefor, and means for operating said brake mechanisms with respect to said drum a predetermined inter al of time apart, to prolong the acceleration of said elevator mechanism.

a sourceof power for driva plurality of brake mechan elevator ing effect of said brake mechanisms upon said elevator mechanism.

1:2. The combination with an elevator mechanism, of a source of power for driving the same, a plurality of brake mechanisms, means for discontinuing the operation of said elevator mechanism by said-source of power, and means for setting said brake mechanisms at different times with respect to discontinuation of operation of said elevator mechanism by said source of power for prolonging the negative acceleration of said elevator mechanism by said brake mechanisms.

18. The combination with an elevator mechanism, of an electric motor for driving the same, a plurality of brake mechanisms, means for energizing said motor, electro magnetic means controlling said brake mechanisms, and means co-operating with said electro-magnetic means for causing control of said brake mechanisms at different times with respect to the energization of said motor for prolonging the positive acceleration of said elevator mechanism.

14-. The combination with an elevator mechanism, of an electric motor for driving the same, a plurality of brake mechanisms, means for deenergizing said motor, electromagnetic means controlling said brake mechanisms, and means co-operating with said electromagnetic means for causing control of said brake mechanisms at different times with respect to the deenergization of said motor for prolonging the negative acceleration of said elevator mechanism.

15. The combination with an elevator mechanism, of an electric motor for driving the same, brake mechanisms, a plurality of electro-magnetic devices each controlling one of said brake mechanisms, switching mechanism controlling simultaneous energization of said motor and at least one of said electromagnetic devices, and means for delaying the control of another of said brake mechanisms by its electromagnetic device, whereby reduction of braking effect upon said elevator mechanism is prolonged.

16. The combination with an eleigator iechanism, of an electric motor for dr'vin the same, brake mechanisms, a plurality or electro-magnetic devices each controlling one of said brake niechanisn'is, switching mechanism controlling simultaneous deenergir iation of said motor and at least one of said electroanagnetic devices, and means for delaying the setting of another of said brake mechanisms, whereby the negative acceleration of said elevator mechanism prolonged. 1?. The combination with an elevator mechanism, of an electric motor for driving the same, brake mechanisms, an electromagnetic device for controlling each of said brake mechanisms, switching mechanism for simultaneously energizing and deenergizing said motor and said electrormagnetic devices, and means associated with one of said brake mechanisms for retarding its movement, whereby the acceleration of said elevator mechanism is prolonged.

18. The combination with an elevator mechanism, of a brake drum therefor, a plurality of brakes movable independently of each other and co acting with said drum, means biasing each of said brakes towards said drum, an electromagnetic device for actuating each of said brakes in opposition to its said biasing means, and means for causing movement of said brakes toward or away from said drum at different times.

19. The combination with an elevator mechanisn'l, of a brake drum therefor, a plurality of brakes movable independently of each other and cor-acting with said drum, means biasing each of said brakes towards said drum, an electro-magnetic device for actuating each of said brakes in opposition to its said biasing means, means for causing simultaneous energization of said electromagnetic devices, and means for retarding the movement of one of said brakes by its electro- :iagnetic device.

20. The combination with an elevator mechanism, of a brake drum therefor, a plurality of brakes movable independently of each other and co-acting with said drum, means biasing each of said brakes towards said drum, an electric-magnetic; device for actuating each of said brakes in opposition to its said biasingmeans, means for causing simultaneous .energization of said electromagnetic devices, and means for retarding the movement of one of said brakes towards said drum u 3011 deener ization of its electro-magnet-ic device.

'21. 'lhe combination with an elevator mechanism, of a brake drum therefor, a plurality of brakes ce-acting with said drum, concentrically pivoted levers connected, respectively, to saidbrakes, independently operating means for biasing each of said brakes towards said drum, an electromagnetic device operating upon ,each'of said lovers in opposition to said biasing means, and means for ensuring the movement of said brakes at different times with respect to said drum,

22. Elevator mechanism comprising a brake drum, a plurality of brakes co-acting with said drums, a bracket, a plurality of levers concentrically pivoted on said bracket, means connecting each of said levers with one'of said brakes, rods secured'to said bracket, spring abu-tments carried by said rods, springs intervening between said abutments and said brakes for biasing said brakes towards saiddrum, an electro-m'agnetic device operating upon each of said levers in opposition to the spring, and means for ensuring movement of said brakes at different times With respect to said drum.-

3. Elevator mechanism comprising a brake drum. a plurality of brakes co-acting with said drum, a bracket, a plurality of levers concentrically pivoted on said bracket, means connecting each of said levers with WILLARD s. ATKINSON.

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