US1969368A - Rotation mechanism for percussive tools - Google Patents

Description

Aug. 7, 1934. c. c HANSEN 1,969,368

ROTATION MECHANISM FOR PERCUSSIVE TOOLS Filed July 10, 1931 INVENTOR. 61km" ed CHM/Sew.

HIS ATTORNEY Patented Aug. 7, 1934 UNITED STATES ROTATION MECHANISM FOR 'PERCUSSIVE.

roons Charles C. Hansen, Easton, Pa., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corpora'tion of New Jersey Application July 10, 1931, Serial N0..549,865

2 Claim.

This invention relates to percussive tools, but

' t plifled and durable rotation mechanism for ef-.

' parts, 7

Figure 1 is a sectionalelevation of a rock drill.

fecting a step by step rotative movement of the working implement between successive blows of the hammer piston of the tool.

Anotherobject is to effect engagement of the elements whereby such step by step rotation is brought about through the medium of pressure fluid, and a further object is to assure engagement of the rotation :locking devices both during the operative and inoperative periods of the tool.

Other objects will be in part obvious and in part pointed out hereinafter. 1 j

In the accompanying drawing illustrating a preferred. form of the invention and in which similar reference equippedwith rotation mechanism constructed in accordance with the practice of the invention.

Figure 2 is a transverse view taken through Figure 1 ion the'line 2-2 looking in the direction indicated by-the arrows, and

Figure 3 is a sectional elevation of a detail taken through Figure 1 on the line 33 looking in the direction indicated by the arrows.

Referring more particularly to the drawing, A designates generally a rock drill comprising a cylinder B, the interior of which constitutes a piston chamber C to accommodate a reciprocatory hammer piston D. The piston chamber C is provided in this instance with a free exhaust port E which is controlled by the head, F of the piston D. 1

A closure is provided for the front end of the piston chamber C by a front head G havinga bore H which may serve as a guide for an extension or stem J carried by the piston D. The stem.

J is shown provided with the usual flutes K to receive ribs L of a chuck O encased by the front head G wherein it may rotate freelyto effect rotative movement of a working implement (not shown) but which the said chuck may be-adapted to accommodate in a well known manner.

In the rear end of the cylinder B is an enlarged bore P to receive, among other things, valve mechanism designated generally by Q and comprising a valve chest R which is shown as consisting of a pair of plates S and T. The plate T seats in the bottom of the bore P adjacent the rear end of the piston chamber C for which it forms a closure and the rear end ofthe plate T serves as a characters refer to similar,

seat for the plate S and also for a valve U of the oscillatory plate type arranged in a valve cha ber V in the plate S.

The valve U controls the admission of pressure fluid to the ends of the cylinder. Such pressure fluid in the present instance is conveyed to the rear end of the cylinder by a rear inlet passage W in the plate T and being controlled by one wing of the valve U, and pressure fluid is conveyed to the front end of the piston chamber 0 by a front inlet passage X formed in the plate T and the cylinder B and being controlled by the other wing of the valve U. r

Arranged on the rear end of the cylinder, for which it forms a closure, is a back head Y which may be secured tothe cylinder as may also be the front head G by the usual spring pressed side bolts (not shown). As an additional function the back head Y serves as a casing for a throttle valve Z illustrated as being of the rotary type and having a handle I) for its manipulation.

The throttle valve Z has the usual central bore or chamber c which may be in constant communi-- cation with the source of pressure fluid supply. In the wallof the throttle valve Z is a" port :1 whichin the open position of the throttle valve registers with a passage e in. the back headand opening into a supply reservoir 1, also in the back head. By forming the supply reservoir 1 of annular shape a central plug g is formed in the back head Yand the front end it of said plug is .preferably flush with the corresponding 'end of a flange a of the back head which projects into the rear end of the cylinder B.

As a preferred form of construction the plug g is provided at its front end with a reduced portion It to receive a ring 0 which may be press-fitted thereon. The outer periphery of the ring is of somewhat smaller diameter than the outer bound.- ing surface of the supply reservoir 1 wherewith it cooperates to define an annular outlet opening p for the supply reservoir.

The rotation mechanism constructed in accordance with the practice of the invention comprises the usual rotatable rifle bar q which extends through the plates S and T and into the piston chamber C to interlockingly engage the piston D in a well known manner. The rifle bar q carries an integral head 1' which lies between the plate S and the back head Y and carries at its rear end a trunnion s which extends into a bore t in the plug 9/ of the back head.

Preferably a bushing u is disposed in the plates S and T and around the rifle bar q to serve as a renewable bearing surface for the rifle bar and also to prevent uncontrolled admission of pressure fluid from the valve chamber V into the rear end of the piston chamber 0.

Encircling the head r is a ratchet ring 1) which is seated with one end upon the plate S and acts with its other end as a seat for the back head Y and the ring 0, both of which are accurately fitted to prevent leakage of pressure fluid between their surfaces and the cooperating surface of the ratchet ring 1). In the ratchet ring 1) are supply passages w to afford communication between the supply reservoir 1 and the valve chamber V.

The ratchet ring 1) may be suitably held against rotary movement in the bore P by a keyor pin a: seated in suitable registering groovesin the outer and inner surfaces of the ratchet ring '0 and the held in readiness for engagement with the teeth 3' thehead r is provided with bores 4, that is, one bore for each pawl, to receive plungers 5 which may reciprocate freely within the bores 4 and bear with their outer ends against the pawls y.

The bores 4, in effect, serve as cylinders to the inner or rear ends of which is supplied pressure fluid by passages 6 extending through the head 1" and the trunnion s and registering with an annular groove 7 in the plug 9'. In the back, head Y is a passage 8 which opens with one end into the annular groove 7 and registers at its other end with an annular groove 9 in the periphery of the throttle valve Z. I

The annular groove 9 maybe of such length that it will be in constant registry with the passage 8 in all of the various positions which the throttle valve 2 may occupy in practice and is also in constant communication with the chamber 0 in the throttle valve through a port '10 in the throttle valve.

The head r of the riflebar. q is of sufficiently smaller diameter than the'interior of the ratchet ring to permit the free and constant admission of pressure fluid throughout the entire interior of the ratchet ring during the operation of the rock drill. Such pressure fluid may be admitted into the ratchet ring from any suitable source but is preferably conveyed thereto by a passage 11 located in this instance in the ring 0 and leading from the supply reservoir 1.

' Means are provided to effect a suitable reduction in the value of the pressure fluid within the ratchet rin 21, and which pressure fluid acts against the outer ends of the plungers 5, so that the pressure fluid acting against the inner ends of the plungers 5 may predominate to press the pawls y into engagement with the teeth 3. In furtherance of this end the ratchet ring 21 is provided with an atmospheric vent 1.2 which also extends through the wall of the cylinder B. In the vent 12 is formed a tapered seat 13 for a needle valve 14 which is threaded into the ratchet ring 1) to control the vent 12.

The operation of the device is as follows: With the throttle valve in the open position wherein the port cl registers with the passage e,pressure fluid will flow through the supply reservoir 1 and the supply port w into the valve chamber V.

ratchet ring '0.

From there the pressure fluid will be, distributed to the ends of the piston chamber C by the valve U in the usual manner to eifect reciprocation of the piston D.

At the same time pressure fluid will flow into the bores 4 through the passages connecting said bores with the interior of the throttle valve Z and pressure fluid will also flow from the supply reserveoir 1 through the passage 11 into the By correctly adjusting the needle valve 14 the value of the pressure fluid within the ratchet ring 1: is constantly maintained below the value of the pressure fluid within the bores 4 so that a preponderating pressure may act against the inner ends of the plungers 5 to press the pawls y gently but positively into position to engage the teeth 3. The pressure differential which may obtain in the bores 4 and in the ratchet ring 1) may be determined by what may be considered desirable or by the nature of the'work for which the tool is employed.

With the hammer piston D in operation and assuming it to be starting on its rearward strokeas illustrated in Figure 1, and with the pawls pressed into engagement or in position'to en-- gage the teeth 3, the hammer piston will describe a partial revolution during its rearward stroke and, being connected through the chuck mechanisms 0 with the working implement, will therefore shift the working implement to a new position in the drill hole for a succeeding blow of the hammer piston. 7

Upon reversal of the piston D in the rear end of the piston chamber 0 and during the subsequent forward stroke of the piston the rifle bar q will be rotated a partial revolution. thus shifting the pawls y to a new position in theratchet ring '0. This rotary movement of the rifle bar may be effected with a minimum resistance to theforce acting against the piston D to drive it against the working implement. This is due to the fact that'only a comparatively light pressure is exerted against the inner ends of the plungers 5. The pawls will therefore pass lightly over the teeth 3 instead of exerting a heavy drag thereon as would be the case were only the in ner ends of the plungers 5 exposed to pressure Whenever the working implement becomes stuck in the drill hole the throttle valve Z may be rotated to a position to out off the supply of pressure fluid to the supply chamber V and the tool may then be manipulated to-free the working implement, as is the usual practice in the operation of hand held tools. In'the closed position of the throttle valve'pressure fluid will be supplied to the bores 4 and such pressure fluid will hold the pawls y firmly in engagement with the ratchet ring 1:. The entire rotation mechanism will then remain suitably interlocked so that prying or turning pressure may be applied to the rear extremity of the tool to free the working implement from the work.

- I claim: 7

1. A fluid actuated, percussive tool comprisin a casing, a hammer piston, a rifle bar for the hammer piston, a ratchet ring encircling the rifle bar, pawls carried by the rifle bar, fluid actuated plungers in the rifle bar to actuate the pawls into engagement with the ratchet ring, and means for constantly supplying pressure fluid to the plungers during the operative and inoperative periods of the tool.

2. A fluid actuated percussive tool comprising a casing, a hammer piston, a throttle valve for engagement with the ratchet ring, and. means including ports and passages for constantly supplying pressurc fluid to the plungers from the bore during the operative and inoperative periods of the tool CHARLES C. HANSEN.

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