US710758A - Mechanical brake. - Google Patents

Description

No. 7|o,75s.' Patented not. 7, |902. E. P. coLEMAN & s. E. HITT, MECHANICAL BRAKE.

(Application filed Nov. 21, 1901.) (No Model.) l 3 Sheets-$heet l.

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\ if@ is Patented 001.7, |902;4

E. P. COLEMAN & S. E. HITT.

MECHANICAL BRAKE.

(Apphcahon led Nov 21, 1901 a sheets-sheet 2.

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No. 710,758. y Patented ont. 7, |902. E-. P. COLEMAN & s. E. 'H|TT.*

MECHANICAL BRAKE.

(Application filed Nov. 21, 1901,.)

3 Sheets-Shee `3.

Will

(No Model.)

Unir-.an Srjnrns FATE/NT OFFICE.

EDGAR I), COLEMAN AND SAMUEL E. III'IT, OF CHICAGO, ILLINOIS.

MECHANICAL BRAKE.

SPECIFCATON :forming part of Letters Patent No. 710,758, dated October 7, 1902 Original application lcd October 23,1900, ScrialNo. 34,074. No. 83.179.

To @ZZ tf1/7,0m, t 'may conceive:

Be it known that we, EDGAR P. COLEMAN and SAMUEL E. HITT, of the city of Chicago, county of Cook, and State of Illinois, have invented certain new and useful .Improvements in Mechanical Brakes, of which the following is a specification.

Oui-invention relates to hoisting machinery or similar apparatus in which there is a tendency for the load to turn the driving mechanism or motor backward, and more particularly to improvements iu automatic mechanical brakes forjib, ganntree,or overhead travcling cranes usually operated by electric power. f

The automatic friction-brakes as heretofore constructed have been objectionable in their operation, due to the fact that the full power of the electric motor (always available) could not be availed of for hoisting purposes on account of necessity for the motor to overcome the larger part of the friction of the brake in addition to the lifting of the load when once the brake had been brought into operation-that is to say, if the load had been lifted by the hoisting mechanism and the brake brought into operation to sustain it the actuating power had to act against the load, and the larger part of the brake-friction when it was desired to raise such load still higher,as the friction torque of the brake had to be equal to or greater than the torque produced on the hoisting-shaft by the load in order to sustain it and the motor had to overcome fifty per cent. or more of suoli friction to release the brake. l/Vhen it operated again to hoist the load, it will be seen that the lifting capacity of the hoisting apparatus was not equal to the capacity of the motor, but only about two-thirds or even a less proportion of such motor capacity. A further objection to said antomatic brakes has been that after the brake had operated to sustain the load and the driving-shaft operated to lower the lead the brake was first partly released, permitting the load to drop a certain distance until it caused the brake to again operate and hold it until the driving-shaft again released the brake,thereby accomplishing the lowering by a series of starts and jerks,\vhich caused very Divided and this application tiled November 2l, 1901. Serial (No model.)

objectionable vibrations throughout the eutire apparatus.

The object of our invention is therefore to provide an automatic brake which shall permit the actuating crdriving motor to exert its full power in lifting the load whether such brake is at the time under torque in sustaining a ,load or not. f

Another object of our invention is to provide an automatic brake which may be operated at all times without producing vibrations. Our invention consists in stationary friction members suitably connected, movable friction members, means between said movable members and connected to the hoistingshaft for forcing the movable members apart and against said stationary members, and a driving-shaft provided with means for engaging either the hoisting-shaft or the movable friction members to positively operate the same thereby; and, further, ourinvention consists in various constructions and combination of parts,all as hereinafter described, and particularly pointed out in the claims.

Our invention will be more readily understood by reference to the accompanying drawings, forniing a part of this specification, and inwhich Figure l is a longitudinal vertical section of an automatic friction-brake embodying our invention. Fig. 2 is a cross-section taken on line 2 :c 2 Qc, Fig. l. Fig. 3 is an elevation of one of the interlocking friction members. Fig. itis an inner end View thereof. Fig. 5 is a section taken on line `5 y y of Fig. e. Fig. (i is a section taken on line 6 ,e ,e of Fig. i. Fig. 7 is an outer end view of the same. Fig. 8 is an elevation of the hoisting-shaft' and brake-actuating cam-head. Figs. 9 and IO are left and right end views thereof. a longitudinal section of the same taken on line ll `t ll u of Fig. 9. Fig. l2 is a longitudinal section taken on line l2 'u l2 t* of Fig. i). Fig. I3 is an elevation oi' a portion of the driving-shaft, showing the connecting-keys therein; and Fig. 14C shows a modification of the driving-shaft coupling pins or keys.

As shown in the drawings, our invention consists in the stationary housings 2, provided with end plates 3 and Lt and inclosing Fig. Il is l IOO the friction members, the driving-shaft 5, extending through the center of the housing and journaled in suitable bearings outside thereof, and the hoisting-shaft 6, in the shape of an elongated sleeve, through which the drive-shaft 5 passes, and having secured at one end the hoisting-pinion 7 and provided at the other end with the integral-acting camhead Sforengaging the friction members. The friction members consist of the friction-heads 9 and 10and the friction-heads 11 and 12. The friction member 9 is shown in detail in Figs. 3 to 7 and consists of a disk-shaped body part 13, acentral sleeve-section 14, extending from the outside thereof, adapted to be mounted upon the driving-shaft 5 and provided in the outer periphery with two or more longitudinal grooves 15, and a series of lingers or projections 16 on the inner side of the disk-shaped part 13 with spaces between them of the same width as the said projections, the cross-cams 17 also projecting from the inner part of part 13 and the recesses 18 for the reception of the ends of pin 23. Friction member 10 is a substantial counterpart of member 9 and differs therefrom, as shown in Fig. 1, merely in having a larger central aperture and sleeve to accommodate the hoisting-shaft 6 and has no recesses corresponding to recesses 1S of part 9. lhe fingers or projections 16 vof the respective members 9 and 10 interlock with each other, forminga positive clutch connection between said parts and at the same time permitting of their movement toward and from each other. The friction disks or plates 11 are provided with lugs or projections 2O upon their external peripheries adapted toenterlongitudinalrecesses21,cutin the innerperipheries of the housing 2, whereby said disks or plates 11 are held from rotation. The friction-disks 12 are provided withlugs or projections 22 on their inner peripheries adapted to enter the longitudinal grooves 15in the outer peripheries of the sleeves of friction-heads 9 and 10, whereby said plates or disks 12 are caused to rotate in unison with said heads 9 and 10. The heads 3 and 4 of the housing are each provided with a friction-surface on the inner side thereof to engage with a revoluble friction disk or plate 12 and a stuffingbox on the outer side of the aperture for the shaft to prevent the escape of oil therethrough, and both heads are held to the stationary housing 2 by top bolts or other suitable means. The hoisting-shaft 6 is provid ed with recesses 19 in its inner periphery, near the inner end thereof, the longitudinal shoulders 19 of which engage the ends of lockingkey 23 when the drive-shaft operates to hoist. The said recesses 19 are preferably so located as to be out of alinement with recesses 1S in friction-head 9. In place of the simple pins and slots shown in Fig. 1 we may provide an enlargement or collar 5 on said shaft, the same having a plurality of pins or side lugs 5 entering a plurality of slots or recesses 5 in the sides or faces of the parts 8 and 9.

(See Fig. 1e.) The advantage olfered is strength, the shaft not being weakened as with the cross-pins 23.

The cam-head 8 Aat the inner end of the hoisting-shaft consists of two oppositely-disposed sets of spiral cams S, corresponding to and adapted to cooperate with the spiral cams 17 on the inner faces of the friction-heads 9 and 10 to force them apart when moved in one direction and permit their movementtoward each other when moved in the opposite direction. Between the successive cams 8' are the longitudinal drop sections or jaws S2 and also between the successive cams 17 on the heads 9 and 10 are corresponding drop sections or jaws 172. The number of individual cams in each set may be varied as desired, and the pitch or incline of the same will depend upon the number of frictiondisks employed or the amount of friction required to be developed by said friction members when forced together by the endwise pressure of the cams. In all cases the frictional engagement between the cams and the friction members is very light, and the same oppose very little resistance to the rotation of the hoisting-shaft in a positive direction. The friction at this point between the hoisting and load shaft and the revoluble friction members is so small that the coupling may be defined as an antifriction pressure device. The spiral spring 26 surrounds the cam-head S and engages at its ends the inner faces of the friction-heads 9 and 10 and maintains a slight initial pressure upon the friction members; but this spring is not essential to the successful operation of our device. The housing is provided with. an oilhole 25 at the upper side thereof and has gaskets at its ends to make it oil-tight. Oil is supplied to said housing through hole 25 and fills the lower part of said housing and may rise above the shaft, if desired, the stuffingboxes preventing escape through the central apertures in the end plates.

The operation of the brake is as follows: When the driving-shaft 5 is turned in the direction of the arrow at the lower side thereof in Fig. 1, coupling pin or key 23 is brought into engagement with shoulders 19 of the slots or recesses 19 in the inner side of the hoisting-shaft 6, thereby picking up the latter and moving cam-head 8 to release the friction device, and thereafter picking up the friction-heads 9 and 10 by the engagement of jaws 82 with jaws 172 on the heads 9 and 10, and thereafter carrying the said friction members idly around with it throughout the hoisting operation. When the load has been raised and driving-shaft stopped, the tendency of the load to move backward produces a slight retrogade movement of the hoisting and driving shaft, but the frictionhead remains stationary, permitting the jaws 82 to move away from jaws 172 and the cams 8. to mount upon cams 17 and forcing the friction members into engagement until the IOO IOS

IIO

torque produced by cams 17 upon cams 8 equals the torque produced by the load. Should it be desired to raise the load still higher, the drive-shaft will operate again, as at first described, and expending only the power required by the load, since the cams 1T of the friction-heads 0 and l0 produce no torque to oppose movement of cams S in this direction. \Vhen, however, it is desired to lower the load after the brake has operated to sustain it, the drive-shaft 5 is turned in the direction of the arrow above the same in Fig. l, carrying key away from shoulders 19 and bringing key 23' into engagement with shoulders 1S' of slots or recesses 1S, while key is in an intermediate position relative to the shoulders of its respective slots. By the engagement of key 23' with shoulders 1S' the driving-shaft picks up the interlocked friction-heads 9 and 10 and overcomes the excess of torque produced by the friction members over the opposite torque produced by the load and forces said friction members to slip with a uniform resistance so long as the driving-shaft is turned in that direction.

This is a divisional application, the subject-matter thereof being derived from our pending application, entitled, Mechanical brakes for hoisting machinery, Serial No. 3&,074, filed October 23, 1900, and attention is also directed to our pending application, entitled, Mechanical friction-brake, Serial No. 83,180, filed November 21, 1001.

Having described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. ln a mechanical friction-brake, the combination with the hoisting-shaft of the stationary and movable friction members, cams connected to said movable friction members, and a cam-head arranged between said friction members and connected to said hoistingshaft and adapted to engage the said cams and force the said movable friction members into engagement with the stationary members, and a driving-shaft suitably connected with said movable members and said hoisting-shaft, substantially as described.

2. In a mechanical friction-brake, the combination of the hoisting-shaft, with Ithe plurality of stationary friction members the plurality of connected movable friction members, cams connected to said movable friction members, a cam-head connected to the hoistingshaft, said head being arranged between the cams of said friction members to force said movable and stationary friction membersinto engagement, substantially as described.

In a mechanical brake, the combination of a hoisting-shaft, two sets of stationary and movable friction members, the inner member of each being movable and provided with cams, a cam-head connected to the hoistingshaft and adapted to engage the said cams and force the movable friction members into engagement with the said stationary members, substantially described.

e. In a mechanical brake, the combination of a hoisting-shaft, two sets of stationary and movable friction members, the inner member of each being movable and provided with cams and jaws, a cam-head connected to the hoisting-shaft, provided with corresponding cams and jaws, said jaws being adapted to engage when said head is moved in one direction and said cams being adapted to engage when said head is moved in the opposite direction, substantially as described.

5. In a mechanical brake, the combination of a driving-shaft and a hoisting-shaft, a stationary friction device, a movable friction device, means carried by said hoisting-shaft to force the movable friction device into engagement with the stationary device and means for alternately coupling the driving-shaft with the movable friction device and with thehoisting-shaft, substantially as described.

0. In a mechanical brake, the combination of a driving-shaft, a hoisting-shaft, two sets of connected stationary and movable friction members, the inner member of each being movable and provided with cams, a cam-head carried by the hoisting-shaft and adapted to engage said cams to force the movable friction members into engagement with said stationary members and means to couple the driving-shaft alternately with said head and said movable set of friction members, substantially as described.

7. In a mechanical brake, the combination of a driving-shaft and a hoisting-shaft, two sets of friction devices provided with opposing cams, a cam-head connected to said hoisting-shaft and adapted to engage said opposing cams, devices for alternately coupling said driving-shaft to the hoisting-shaft and to the friction devices whereby movement of the driving-shaft in one direction picks up the hoisting-shaft and releases the friction devices and movement in the opposite direction picks up the friction devices, substantially as described.

8. ln a mechanical brake, the combination of the housing, the hoisting-shaft, the interlocking friction-heads provided with cams and grooved sleeves, movable friction-disks mounted on said sleeves and provided with lugs on their interior peripheries for engagement with said grooves, stationary frictiondisks interposed between said movable friction-disks, the cam-head connected to said hoisting-shaft and adapted to engage the said cams, substantially as described.

9. In a mechanical brake, the combination with the stationary friction members, of the revoluble friction members, suitably connected, the driving-shaft whereon the same are mounted, the load-shaft and the pressure device connected therewith arranged between said revoluole friction members and adapted to force said revoluble members apart when the load-shaft is turned backwardly by the load, substantially as described.

10. ln a mechanical brake, the combination IOO IIO

with the stationary friction members, of the revoluble friction members arranged between said stationary members, the shaft Whereon said revoluble members are mounted,theload shaft concentric therewith, the pressure device arranged on said load-shaft between said revoluble friction members, and means upon said drivingshaft to engage said friction members or said pressure device, according as the driving-shaft is rotated backwardly or positively, substantially as described.

ll. In a mechanical brake, the combination of the casing having the ends 3 and 4, With the revoluble friction members 9 and lO, the driving-shaft 5, the load-shaft 6, the antifriction pressure device provided upon the end of said load-shaft between said revoluble friction members and the pick-up device provided upon said driving-shaft to engage said revoluble friction members or said pressure device, as and for the purpose specified.

l2. In a mechanical brake, the combination of the stationary and movable friction members of equal frictional capacityr,with the driving-shaft having a slot-and-key connection With said movable friction meu1bers,the hoisting-shaft having a slot-and-key connection with said driving-shaft and the double cam provided upon said hoisting-shaft between said movable friction members, substantially as described.

In testimony whereof I have hereunto subscribed my name, in the presence of tivo Witnesses, this 21st day of September, 1901.

SAMUEL E. HITT.

In presence of- JOHN H. GREGG, A. J. EWING.

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