US1020014A - Brake for hoisting-machinery. - Google Patents

Description

M55555; I I7UEZ7/UZ G. A. ARMINGTON.

BRAKE FOR HOISTING MACHINERY.

APPLICATION FILED OOT.19, 1910.

1,020,014. Patented Mar. 12, 1912.

' 2 SHEETSSHEET 1.

c0 LLLL u PLANDORAPH 20., WASHINGTON, n. c.

' G. A. ARMINGTON. BRAKE FOR HOISTING MAGHINERY.

APPLICATION FILED OUT. 19, 1910. I

Patented Mar. 12, 1912.

2 SHEETS-SHEET 2.

' .Z'nusmar 5 A ar-nay.

/AMM M [LIT GEORGE A. ARMING'ION, 0F WICKLIFFE, OHIO.

BRAKE FOR HOISTING MACHINERY.

Specification of Letters Patent.

Patented Mar. 12, 1912.

Application filed October 19, 1910. Serial No. 587,822.

T 0 all whom it may concern:

Be it known that I, GEORGE A. ARMING- TON, a. citizen of the United States, residing at VVickliife, in the county of Lake and State of Ohio, have invented a certain new and useful Improvement in Brakes for Hoisting Machinery, of which the following is a full, clear, and exact description, reference being had to the accompanying drawm s.

This invention relates to hoisting mechanism and has for its especial object the provision of a brake which shall operate to securely lock the hoisting drum and retain the load in any desired position and which can furthermore be disengaged by reversing the direction of rotation of the motor and caused to efiect a smooth and steady reverse movement of the drum and lowering of the load. Previous brakes, so far as I am aware, have included a rotatable friction plate which revolved freely while the load was being raised and was prevented from rot-ation reversely when the load was being 1owered. This arrangement necessitated a separate retaining mechanism for the brake plate itself as well as a complicated and refined mechanism for allowing the operation of the brake from a distance. This application discloses a brake which operates automatically whenever the motor stops, which is entirely disengaged when the motor is running forward and hoisting the load, and which is partially released when the motor is reversed and running backward.

One embodiment of my invention is shown in the accompanying drawing in which I Figure 1 is a plan View of complete hoisting gear embodying my invention; Fig. 2 1s a cross sectional view taken on the line 2-2 of Fig. 1; Fig. 3 is a perspective view of the rear face of the motorgear; Fig. at is a perspective view of-the stationary friction plate; Fig. 5 is aperspeCtive view of the brake cam; and Fig. 6 is-a perspective view of the front friction plate.

Describin the parts by reference characters, the holsting mechanism herein shown consists of a motor 1 having ashaft 2 upon which is keyed a pinion 3 which meshes with the motor gear 4 carried by the shaft 5.

This shaft is journaled near' one end in a box 6 carried by the frame 7 which also SIIP- ports the motor and hoisting drum, and'near the other end in another box at the right of the drum and not illustrated. This drum is indicated at 8 and is sleeved onto shaft 5 as shown at 8 in Fig. 2. A pinion 9 is keyed to shaft 5 on the opposite side of box 6 from the drum and drives the latter through the agency of gears 10 and 11 carried on countershaft 12, the last named gear meshing with a gear 13 attached directly to the drum. Owing to this arrangement it will be seen that shaft 5 and drum 7 rotate in the same direction, though at different speeds, thus decreasing friction as well as providing a more compact construct-ion. Between motor gear 4: and pinion 9 the brake 1 1 is placed, this being the important feature of my invention.

The body of the brake consists of a flat circular friction plate 15 rigidly attached to the frame as by a footor bracket 16 bolted thereto. In Fig. 1 I have shown this plate as provided with a journal 17 for the motor shaft. I prefer to make this plate with a comparatively thin central web 18 and a thickened rim 19 in order to exclude oil and dirt from the friction faces. This web is provided with a central hole 20 through which the shaft "5 passes, and with friction disks 21 of Wood, fiber, leather, or the like against each face thereof. Keyed rigidly to the shaft at one side of this stationary plate is a rotary friction plate 21 which is adapt-- ed to fit within the rim 19 of the stationary plate and to contact the disk therein, and

upon the other side of the stationary plate a second rotary plate 22 is placed, the latter being loosely sleeved upon the shaft and adapted to be drawn against the stationar plate by means now to be described.

The end of shaft 5'is threaded as shown in dotted lines at 23 (Fig. 2) and a cylindrical collar 24: is screwed thereon. This collar is provided with a plurality of keyways 25 any one of which can bebrought into register with a single key-Way out in the shaft to permit locking of the collar in any adjusted position. The face of this collar is made in the form of a long cam 26 having an abruptshoulder 27 parallel with the axis of the shaft, and the adjacent face of the'front friction plate 22 is formed with a similar cam 28 and shoulder 29. The out- :sideedge of the collar 24 is. provided with a pair of longitudinal key-ways 30 in which feathers 31 are rigidly secured, as by fillister head screws 82. Upon this collar the motor a large central opening 33 provided with extended keyways 34:, adapted to receive the feathers 31 and to prevent complete rotation of the gear upon the collar and forming what I have termed a lost motion driving connection. The inner face of said gear is provided with spaced projections 35 adapted to contact with lugs 36 carried by the front friction plate at a time and for a purpose to be described later.

The operation of the device is as follows: Suppose that the motor be operated in a direction to raise the load. The effect will be to turn the motor gear upon the collar 24 until the lost motion is taken up, after which the train of gears is actuated to turn the drum. At the same time the engagement of the abruptfaces 27 and 29 of the two cams carries the friction plate without side thrust and the brake is not engaged. It now the current be turned ofl the motor will cease to exert a pull upon the drum and the load will tend to turn the drum in the opposite direction. The friction of plate 22 upon its seat causes it to lag behind the shaft 5 and the mutual action of cams 26 and 28 serves to draw the friction plates 21 and 22 firmly against opposite sides of the stationary plate with a force depending upon the weight of the load, the slope of the cams, and the quality of oil used on the cams. The shaft 5 has suflicient end play to permit the necessary movement to bring the plate 21 firmly against the stationary friction plate 15. If now it is desired to lower the load the motor is reversed. The first effect is to rotate gear 4 idly upon the collar 24: until the projections 35 engage the lugs 36 as shown in Fig. 1, after which the motor gear positively drives the plate against the friction of its contact with the stationary plate and the load is steadily lowered. This contact of projections 35 and lugs 36 ought to take place in advance of any contact between the feather 31 carried by the collar and the rear shoulder of the key-way 34: in the motor gear, since otherwise the effect would be to positively rotate the cam against the front friction plate and set the brake all the more tightly,thus increasing the work necessary for the motor to do in lowering the load besides heating the parts unnecessarily. "In case the load is not suflicient torotate the gears, as might be the case where only the naked tackle was attached to the drum the gear train would have to be positively driven by the motor in order to unwind the fall. In this case the front friction plate is driven by the pr0jecti0ns"35. of the motor gear, .but owing to the fact that .the ,shaft 5 tends to follow'rather thanprecedej'th'e gear the latter now' moves over the collar untiltherear wardshoulder of its key slot engages feather 31 and positively'rotates shaft 5. It will be seemtherefore, that the motor does work in lowering a load as well as in raising it, and that the work done depends upon the weight of the load. If the load is heavy the friction plates are tightly gripped and the motor has to overcome the friction, (aided of course by the load), whereas if the load is very light there is no braking efi ect to be overcome. The amount of braking effect can be varied by changing the angles of the cam and by varying the quality and amount of lubricating oil supplied to the parts. In fact, the braking effect can be so nicely adjusted that it scarcely overbalances the load and the amount of work necessary to lower the weight is very small. The factor of safety should not be made too small, however, as the accidental presence of oil on the friction disks or the too great dryness of the cams might cause slipping. It will also be seen that when the load is started upward after having been moved up part way and held by the brake, the first action is the taking up of the lost motion, after which the shaft 5 is positively rotated by the feather 31. The cams quietly disengage and release the brake and the load is smoothly transferred from the brake to the motor.

This invention is particularly valuable in connection with elevators in which all control must be from the movable plat-form of the elevator, and in connection with traveling cranes in which the changing position of the hoisting mechanism prohibits the presence of a workman and renders an auto matic means controllable from a distance an absolute necessity.

It will be understood that this invent-ion is susceptible of a great number of changes and variations without essentially modifying the method of operation, and all such variations and changes whether in size, shape, arrangement, disposition or relation of parts, I consider within the scope of my invention so far as they fall within the terms of the claims hereto annexed.

Having thus described my invention, what Iclaim is:

1. In an automatic mechanical brake, the

ofthe fixed friction plate, a rotatable friction plate sleeved on the shaft on the opposite side of the fixed friction plate, a cam carried by said rotatable friction plate and adapted to cooperate with the cam on the shaft, a driving wheel sleeved upon said shaft, and means provided in connection with said driving wheel, shaft, and rotatable friction plate by means of which the friction plates are released in hoisting, gripped when hoisting ceases, and partially released when lowering.

" .2. In a'hoisting mechanism, in combination, a shaft, a cam secured to said shaft, a driving wheel loosely mounted upon said cam and having a lost motion driving connection therewith, a drum adapted to sustain a load and to be rotated by said shaft to raise and lower said load, a stationary friction plate associated with said shaft, a friction plate between said cam and said stationary friction plate and adapted to be rotated by the rotation of said shaft, said rotatable friction plate having a helical cam surface engaging with said first cam, the cam surfaces being arranged to force said rotatable friction plate away from said driving wheel against said stationary friction plate by the pulling of the load on the drum, and means adapted to be operated upon the retrograde motion of said driving wheel with respect to said cam for reducing the friction between said plates.

3. In a hoisting mechanism, in combination, a shaft, a cam secured to said shaft, a driving wheel loosely mounted upon said shaft and having a lost motion driving connection therewith, said driving wheel also having laterally extending abutments projecting therefrom in the same direction as the inclined surface of said cam, a drum adapted to sustain a load and to be rotated by said shaft to raise and lower said load, a stationary friction plate associated with said shaft, a friction plate loosely sleeved upon said shaft adjacent to said driving wheel and adapted to be rotated together with said shaft, said rotatable friction plate having a helical cam surface engaging with said first cam, the cam surfaces being arranged to grip said friction plates together by the pulling of the load on the drum, said rotatable friction plate also having abutments on the side thereof adjacent to said driving wheel and adapted to be engaged by said first abutment, whereby the rotating friction plate is moved over the stationary plate upon a retrograde rotation of said driving wheel.

4. In a hoisting mechanism, in combination, a shaft, a cam secured to said shaft, a driving wheel loosely mounted on said cam and having a lostmotion driving engagement therewith in both directions, abutments carried by said wheel on the same side with the'inclined surfaces of said cam, a drum adapted to sustain a load and to be rotated by said shaft to raise and lower said load, a sta tionary friction plate associated with said shaft, a rotatable friction plate between said stationary friction plate and said wheel and having a cam surface complementary to said first cam, engaging portions formed on said first cam and on said rotating friction plate, whereby said plate may be driven by said cam when said wheel is rotated in a direction to raise a load, the inclined surfaces of said cams being arranged to cause said rotating friction plate to approach the stationary friction plate upon a retrograde rotation of said shaft caused by said drum, and abutments on the rotating friction plate adapted to be engaged by the abutments on the driving wheel by means of which the rotating friction plate is moved over the stationary plate upon a retrograde rotation of said driving wheel.

5. In a hoisting mechanism, in combination, a shaft, a cam secured to said shaft, a drum adapted to sustain a load, and to be rotated by said shaft to raise and lower said load, a friction plate surrounding said shaft at a point intermediate its ends and held against rotation in both directions, a rotatable friction plate attached to said shaft at one side of the stationary plate, a second rotatable friction plate loosely sleeved upon said shaft at the other side of said stationary plate, one of said friction plates having a cam surface and abutments, and a driving wheel loosely sleeved upon the shaft and having abutments adapted to engage the abutments on said plate and positively drive the same upon retrograde rotation of said wheel, said driving wheel also having means adapted to engage said shaft and positively drive the same upon forward rotation thereof.

6. In a hoisting mechanism, in combination, a shaft, a drum adapted to sustain a load and to be rotated by said shaft to raise and lower said load, a friction plate surrounding said shaft at a point intermediate its ends and held against rotation in bot-h directions, a rotatable friction plate attached to said shaft at one side of the stationary plate, a second rotatable friction plate loosely sleeved upon said shaft at the other side of said stationary plate, a laterally facing cam carried by said loosely sleeved friction plate, a cooperating cam rigidly attached to said shaft and adapted to grip said rotatable friction plates against said stationary plate upon a retrograde rotation of said shaft by said load, and a driving member adapted when driven in a forward direction to positively drive said shaft, and when driven in the opposite/direction to engage said loosely sleeved friction plate to rotate the same in a direction to lower the load.

7. Ina hoisting mechanism, in combina tion, a shaft, means for rotating said shaft, a drum adapted to sustain a load and to be rotated by said shaft to raise and lower said load, a friction plate surrounding said shaft at a point intermediate its ends and held against rotation in both directions, a rotatable friction plate attached to said shaft at one side of the stationary plate, a second rotatable friction plate loosely sleeved upon said shaft at the other side of said stationary plate, means for driving said friction plates over each other Without friction during the rotation of said shaft in a direction to raise the load, and means for drawing said rotatable friction plates together and gripping the stationary plate upon a retrograde rotation of said shaft caused by said drum.

8. In a hoisting mechanism, in combination, a shaft, means for rotating said shaft in both directions, a drum adapted to suetain a load and to be rotated by said shaft to raise and lower said load when said shaft is rotated in appropriate directions, a friction plate surrounding said shaft at a point intermediate its ends and held against motion in both directions, a rotatable friction plate attached to said shaft at one side of the stationary plate, a second rotatable friction plate loosely sleeved upon said shaft at the other side of said stationary plate, means for driving said friction plates over each other without friction during the rotation of said shaft in a direction to raise the load, means for drawing said rotatable friction plates together and gripping the stationary plate upon a retrograde rotation of said shaft caused by said drum, and means for partially releasing the pressure between said friction plates upon a retrograde rotation of said shaft caused by said rotating means.

9. The combination, with a shaft and a driven member adapted to be rotated by said shaft, of a stationary friction plate associated with said shaft, a rotatable friction plate sleeved upon said shaft adjacent to said first friction plate, a laterally facing cam carried by said rotatable friction plate, a cam carried by said shaft and adapted to cooperate with said first mentioned cam to force said friction plates into contact upon retrograde rotation of said shaft, a driving wheel sleeved on the cam on said shaft and provided with means for preventing operative engagement of said cams during the forward driving of said wheel and for directly driving said rotatable friction plate upon the retrograde rotation thereof, said wheel and cam having a driving interengagement during the forward movement of said wheel and also having a driving interengagement during the retrograde move ment of said wheel, there being sufficient lost motion between said wheel and cam so that said latter engagement does not take place until after the driving engagement of said wheel and friction plate.

In testimony whereof, I hereunto affix my signature in the presence of two witnesses.

GEORGE A. ARMINGTON. WVitnesses:

HAROLD E. SMITH, BRENNAN B. VVEsT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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