US2248375A - Brake - Google Patents

Description

July 8, 1941. c, MOORE 248,375

BRAKE Filed Feb. 28, 1940 3 Sheets-Sheet 1 INVENTOR 2 F 0. Moore ATTORNEYS July 8, 1941.

F. c. MOORE BRAKE Filed Feb 28, 1940 3 Sheets-Sheet 2 INVENTOR FCTMooz-e v ATTORNEYS July; 8, 1941. F, g, MQ RE 2,248,375

BRAKE Filed Feb. 28, 1940 s Sheets-Sheet 3 29 4 J 24 1 25 3 31 1/ (J I H INVENTOR 30 j 11 23 25 BY I FClMoore ATTO R N EYS Patented July 8, 1941 UNITED BRAKE Frank C. Moore, Coalinga, Calif., assignor of twenty per cent to John Edward Jensen, twenty per cent to Joseph J essick and twenty per cent to Vernon L. Ward, all of Coalinga, Calif., and twenty per cent to David E. Peckinpah, Fresno,

Calif.

Application February 28, 1940, Serial No. 321,253

10 Claims. (01. 18891) rigidly set; the fluid circulating piping .being This invention relates to a brake structure, and particularly to one especially designed for use to control the cable hoisting drum of a well drilling rig, though by no means limited to such use.

At present, considerable trouble is had in the oil fields with the brake structures now employed, because of slippage and overheating, drum scoring and other reasons caused by operating conditions and the heavy loads which the brakes are called upon to hold in service. As a result, rigs are frequently tied up while expensive repairs or replacements are being made, all of which adds considerably to the total cost of operations.

The principal object of my invention is to eliminate the present troubles by providing a brake structure so constructed that positive holding against slipping under any-load is assured without danger of overheating, whileat the same time a great rangeof the degree of holding coupled with a sensitive control may be had, as when it is desired to ease a drill string down.

A further object is to provide a brake structure which avoids the need of brake bands and similar heating and wearing parts which require frequent adjustment and ultimate replacement, and instead have provided a structure which is self-adjusting, which has no part liable to heavy Wear or give trouble at any time and consequently will function efiiciently for an indefinite period.

A further object is to provide a readily operated means for throwing the braking means entirely out of operation at will, as when it is desired for the drum or shaft to run absolutely free.

A further object is to provide a brake structure which operates with equal efficiency irrespective of the direction of turning of the drum or other rotating part.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly elfective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims. I I

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is an exterior end elevation of my improved brake structure showing the control lever in the position occupied when the brake is omitted;

Figure 2 is a similar view showing the lever in the position occupied when the structure is run-.

ning free.

Figure 3 is a similar enlarged view, with the head plate and adjacent par-ts removed, showing the brake and control mechanism in the braking position as in Fig. 1. g

Figure 4 is a'fragmentary elevation showing the brake mechanism in the release position as in Fig. 2.

Figure 5 is a transverse vertical section of the structure.

Figure 6 is a diagram showing the fiuid circulating system of the structure. l I

Referring now more particularly to the characters of reference on the drawings, the structure comprises a casing I having feet 2 or similar elements whereby it may be firmly mounted in a stationary position. The driven shaft 3 on which the cable drum or other member to be braked is mounted, projects through and is journaled in the casing. The casing has a chamber 4 surrounding the shaft, access to which is had from one end of the casing by means of a head 5 which also preferably forms one of the bearing members for the shaft.

Fixed against rotation on the shaft within the chamber 4 isa circular eccentric 6 normally engaging rollers I mounted onand projecting fromthe inner ends of plungers '8. These plungers,-.

of which there may be any desired number, are slidable in cylinders 9 formed in the casing and disposed in equally spaced relation about and radial with the shaft. Cup leathers ID or similar oil sealing elements are secured on the plungers at their outer end. 7.

The cylinders are closed at their outer end by heads ll each having an oil inlet port l2 and an oil outlet port l3 therein. A compression spring I4, extends between each head and the corresponding plunger to force the latter radially inward, the spring being partly countersunk in the plunger to conserve space.

Turnable on the shaft and located in the chamber 4 between the removable head 5 and the eccentric 6 and close to the'latter is a cam l5 having as many high points thereon as there are plungers. These high points are circumferentially spaced the same as the plungers at their inner end, and are cupped as at IE to provide-seats to match the rounded contour of the plunger ends on the corresponding side of the rollers; the axes of the cups being substantially parallel with the axis of the cam. The radial distance from the bottom of the cups to the shaft is slightly greater than the radial distance from the shaft to said plunger ends when the rollers 1 are engaged with eccentric 8 at its greatest distance from shaft 3. The low points of the cam are so disposed as to offer no interference with engagement of the rollers and the eccentric when the cam is turned clear of the plungers.

The cam is formed with a hub sleeve I! which projects through head 5 and outwardly of said head is rigid with a quadrant l8 limited to substantially 90 movement by stops [9 on the casing and held at either end of its limit of movement by a snap action spring device 28 connected to the casing I and said quadrant.

A control lever 2| is turnable on sleeve ll outwardly of and adjacent the quadrant and is movable relative to said quadrant between spaced stops-22 on the latter. -The quadrant is moved over from one position to the other by a pull on the lever in a corresponding direction, the cam, when the quadrant is in one position, lifting and yieldably holding the plungers clear of the eccentric, and being clear of the plungers when the quadrant isin the other position.

Mountedon the casing on the head end and at one side is a valve casing 23 having a chamber into which conduits 24 discharge, these conduits leading from and .being connected individually to the different outlet ports 13 of the cylinder heads ll. Check valves 25 opening toward the valve casing are interposed in the conduits, preferably adjacent said casing. A single outlet conduit 26 leads from an outlet port 21 in one side-of the valve chamber to an oil reservoirZB. Feed conduits 29' lead from the reservoir to the intake ports, I2 of the cylinder heads, check valves opening toward said heads being interposed in the conduits. The feed may take place by gravity action, or pressure may be applied to the reservoir.

A valve 3l to control the flow throughoutlet conduit 26 is mounted in the valve casing, this valve being preferably of the rotary type with its axisparallel to shaft 3. The valve is arranged to place the outlet port 21 into or out of communication with the portion of the valve casing into which conduits 24 discharge and is connected to lever 2 foroperation with the turning of said lever on the shaft 3 by a link 32. The valve position is such relative to that of the lever that when the lever is moved in the direction necessary to shift the quadrant to. release the holding cam from the plungers and is thrown as far as possible in said direction, the outlet port 21 is shut oif, or in other Words the valve is fully closed, as shown in Fig. l.

The movement of the lever .in the opposite direction permittedbetween the quadrant stops 22 without moving the quadrant is sufficient to turn the valve to a full open position, which position is maintained with the further turning of the lever in said opposite direction necessary to throw the quadrant to its opposite or brake releasing position. In this manner all pressure is relieved whenthe plungers are forced clear of the eccentric by the cam movement, and yet when the cam is in its position clear of the plungers, the valve may be operated through its full actually elfective range by the same lever used in throwing the quadrant and operating the cam. The above ,normal position of the cam, or when it is clear of the plungers, is such that the lowest points of the cam which are below iii the lowest point of the eccentric, are adjacent or substantially in radial alinement with the rollers, as clearly shown in Fig. 3.

In operation it will be seen that the springs act on the plungers to advance the same against the eccentric and at the same time of course act to draw oil into the cylinders beyond the plungers so as to maintain the cylinders filled. At least one of the plimgers is always being acted on by the rotating eccentric to force such plunger radially out, and it will be obvious that if no oil can escape from the filled cylinder, the eccentric will be positively prevented from further rotation. Since such escape is controlled to as fine a point as desired by manipulation of the valve, it Will be seen that the degree of braking effectiveness may likewise be effectively controlled. By the use of individual outlet conduits from the cylinders leading independently to the valve casing, possible leakage in one conduit will not affect the braking action of the plungers with which the remaining conduits are associated. The use of a number of plungers of course not only provides a safety factor as above indicated, but gives a smoother and more even braking action.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Iaving thus described my invention, what I claim as new and useful and desire to secure by Letters Patent, is:

l. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit extending radially of the part and normally engaging the eccentric, means to hold the unit thus engaged, relativelystationary means mounting the unit for movement radially of the part, means to resist radial outward movement of the unit, control means to govern the effectiveness of said resistance means and means between the last named means and said resistance control means to nullify the resistance when the unit is being withdrawn.

2. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit extending radially of the part and normally engaging the eccentric, means holding the unit thus engaged, relatively stationary means mounting said unit for movement radially of the part, means to resist radial outward movement of the unit, control means to govern the effectiveness of said resistance means. a cam turnably mounted on said part adjacent the eccentric and disposed when rotated from a predetermined position to engage the unit at its inner end and lift the same from the eccentric and manual means to control the rotation of the same.

3. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit normally engaging the eccentric, means to hold the unit thus engaged, a relatively stationary cylinder in which the unit is slidably mounted for movement relative to the part, a liquid circulating system having intake and outlet conduits connected to the cylinder radially out from the unit, a check valve in the intake conduit closing away from the cylinder, a control valve in the outlet conduit, normally inactive means to lift the plunger unit from the eccentric and a common means to actuate said lifting means and operate the valve and arranged so that when the unit is being lifted, the valve is wide open.

4. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit normally engaging the eccentric, means to hold the unit thus engaged, a relatively stationary cylinder in which the unit is slidably mounted for movement relative to the part, a liquid circulating system having intake and outlet conduits connected to the cylinder radially out from the unit, a check valve in the intake conduit closing away fromvthe cylinder, a control valve in the outlet conduit, normally inactive means to lift the plunger unit from the eccentric, a movable valve control member and a lost motion connection means between said member and the lifting means arranged to allow the latter to be actuated only when the valve is open and to retain the valve open during the lifting operation.

5. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit normally engaging the eccentric, means to hold the unit thus engaged,

a relatively stationary cylinder in which the unit is slidably mounted for movement relative to the part, a liquid circulating system having intake and outlet conduits connected to the cylinder radially out from the unit, a check valve in the intake conduit closing away from the cylinder, a control valve in the outlet conduit, a normally inactive cam turnable about said rotating part as an axis and arranged when rotated a predetermined amount from an inactive position to lift the unit from the eccentric, a valve control lever turnable axially about the part, a quadrant fixed with the cam, circumferentially spaced lever stops on the quadrant between which the lever is freely movable; such movement being sufficient to move the valve between fully open and closed positions and the valve opening with a movement of the lever in the direction necessary to turn the quadrant and cam in a plunger lifting direction and said valve being arranged to remain open with such turning of the quadrant.

6. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit extending radially of the part and normally engaging the eccentric, means to hold the unit thus engaged, a relatively stationary cylinder in which the unit is slidably mounted for movement radially of the part, means providing for a circulation of liquid into and out of the cylinder radially out from the plunger unit in one direction only, means to control the liquid flow from the cylinder, a normally inactive cam turnable about said rotating part as an axis and arranged when rotated a predetermined amount from an inactive position to lift the unit from the eccentric, a quadrant fixed with the cam, turnable between predetermined limits, means to turn the quadrant and a snap action spring acting to complete the turning movement of the quadrant in either direction and acting to hold the same at either limit of movement.

7. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit extending radially of the part and normally engaging the eccentric, means to hold the unit thus engaged, a relatively stationary cylinder in which the unit is slidably mounted for movement radially of the part, means providing for a circulation of liquid into and out of the cylinder radially out from the plunger unit in one direction only, means to control the liquid flow from the cylinder, a normally inactive cam turnable about said rotating part as an axis and arranged when rotated a .predetermined amount from an inactive position to lift the unit from the eccentric, a quadrant fixed with the cam, turnable between predetermined limits, a snap action spring acting to complete the turning movement of the quadrant in either direction and acting to hold the same at either limit of movement, an actuating lever for the liquid fiow control means turnable axially of and relative to the quadrant adjacent the same and circumferentially spaced lever stops on the quadrant between which the lever is freely movable.

8. A structure as in claim 2 in which the plunger unit includes an eccentric engaging roller; the cam being formed with a roller engaging seat at its high point and the axis of said seat being substantially parallel with the axis of the cam and radially offset relative thereto.

9. A structure as in claim 2 with means on the cam to engage the plunger unit and yieldably hold the two against relative movement when the cam is rotated a predetermined amount from said predetermined position.

10. A brake structure comprising, with a rotating part to be braked, an eccentric fixed on said part, a plunger unit normally engaging the eccentric, means holding the unit in such engagement, relatively stationary means mounting the unit for radial movement relative to the part, means to resist such movement of the unit in one direction, control means to govern the effectiveness of said resistance means and manually controlled means to withdraw the unit from the eccentric.

' FRANK C. MOORE.

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