US1798748A - Blowing device for fluid-actuated tools - Google Patents

Description

March 31, 1931. T. L.-MURPHY 1,793,743

BLOWING DEVICE FOR FLUID ACTUATED TOOLS Filed Jan. 14, 1950 FIQ J.

- INVENTOR. Thomasllluzyvh BYM M H15 ATTORNEY Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE THOKAS L. MURPHY, OI EASTON, PENNSYLVANIA, ASSIGNOR 1'0 INGERSQLL RAND COMPANY, OF JERSEY CITY, NEW'JERSESLA CORPORATION OF NEW JERSEY BLOWING DEVICE FOR FLUID-ACTUATED TOOLS Application flied January 14, 1930. Serial No. 420,703.

This invention relates to fluid actuated rock drills, more particularly to a blowing device for such tools.

The object of the invention is to provide a means for locking the distributor valve of a rock drill in a position to shut off the supply of pressure fluid to one end of the cylinder and to permit the uninterrupted flow of fluid to the other end of the cylinder 1o thereby forcing the piston to one of its extreme positions and permitting the escape of pressure fluid at approximately line pressure to the bottom of the drill hole. The pressurefluid so directed will blow the drill whole free from rock cuttings which might otherwise impede the drilling operation.

In practice it is found that the means ordinarily provided for directing air through the drill steel during drilling is insuflicient to keep the hole free of cuttings. More par ticularly is this true when the hole is deep and the quantity of air required to expel the cuttings is greater than that permitted to flow through the drill steel. In such 2 cases it is desirable to have a supplementary means in the drill itself for directing a powerful stream of pressure fluid tothe bottom of the drill hole. This is ordinarily done by arresting the reciprocation of the piston and permitting fluid to pass along the flutes of the rifle bar or along the flutes of the piston extension through the chuck and into the drill steel. Sometimes, however, the distributor valve of the tool gets into a balanced condition and a modified reciprocation of the piston follows which is inconvenient to the operator and which impairs the efficiency ofthe blowing operation.

The present invention is designed to pro vide a mechanical means for positively looking the distributor valve in one of its positions so that it may not assume a balanced state permitting partial reciprocation of the piston. To attain this result a mechanical latch controlledby a manually operated cam valve is placed in position to engage one end of the distributor valve. The inventlon is more particularly described in the following specification and illustrated in the accompanying drawings in which Figure 1 is a sectional elevation of a rock drill in which the presentinvention has been embodied, showing the distributor valve in its locked position, a

Figure 2 is a cross section of the cam valve taken on the line 22 of Figure llooking in the direction of the arrows, and

Figure 3 is a sectional view of the invention showing the distributor valve in its unlocked position. i

In the drawings in which similar reference characters refer to similar parts a piston 5 is disposed in a cylinder 4 having a piston chamber 7. A fluted extension 6 of the piston passes through a front cylinder bushing 8 which forms the closure for the front end of the piston chamber. In flutedengagement with the piston extension 6 is a grooved chuck 9 which receives a working implement, in this instance a hollow drill steel 10. A front head 11, which is shown only in part, and which may be attached to thecylinder 4 in any suitable manner serves to hold the bushing 8 and the chuck 9 in the assembly.

A back cylinder washer 15 forms the closure of the back end of the cylinder and also acts as a seat for a distributor valve 14 which in this instance, is of the tapered disc type. The distributor valve 14 operates in a valve chamber 16 formed in a valve cover 18 which abuts the rear of the back cylinder washer. A rifle bar 17 passes through the back cylinder washer 15, the valve and the valve cover 18 and engages a rifle nut (not shown) in the piston 5.

The rifle bar 17 has a head 19 with pawls 24. To the rear of the valve cover and en closing the rifle bar head is a ratchet ring 21 having ratchets 20 to engage the pawls 24 and provide a means for rotating the piston on its rearward stroke in a well understood manner.

Surmounting the ratchet ring is a back head 23 having a throttle valve 25, a supply passage 26 and a fluid chamber 27. Passages 22 lead from the fluid chamber 27 to the valve chamber 16 whence fluid is distributed by the distributor valve 14 to the front and rear ends of the piston chamber through the fluid supply passages 12 and 13 respectively.

In the wall of the piston chamber and centrally of the stroke of the piston is an annular groove 32 from which an exhaust port 33 leads through'the wall of the cylinder.

In the cylinder wall near-the exhaust port 33, is a transverse enlargement 34. In the enlargement 34 is a bore 28 in which is located.

a throttle valve 35. This valve may be held in the bore 28 by any suitable means. The method shown being to make the bore smaller at one end than at the other and to provide a neck 36 at one end of the valve 35 which passes throu h the smaller bore and permits a shoulder 3 to seat against the end of the larger bore. In the form illustrated the end of the neck is squared and a valve handle 38 fits over it and is held in position by a pin 39.

A recess 40 is bored into the valve handle and a spring 41 placed therein holds a plug 42 against a depression 43 in the side of the cylinder enlargement 34 to anchor the valve against accidental rotation.

Communicating with the bore 28 and controlled by'the valve 35 is a port 44 through which exhaust fluid from the exhaust port 33 may reach the atmosphere. In the illustration, the port 44 opens to the front of the tool so that exhaust fluid will be expelled away from the operator. The central part of the valve 35 is cut into a cam 45 leaving a hollow space in the bore 28 whereby communication is established between the port 44 and the port 33 and also between the port 44 and a hollow rod or plunger52 which will be described in the next succeeding paragraph.

In the wall of the cylinder leading from the bore 28 to the back cylinder washer 15 is a passage 51 in which is disposed a hollow plunger 52 having ports 54 which register with a port 53 at the rear end of the piston chamber. Located in a passage in the rear cylinder washer is a plunger or latch 46 which may enter a recess 50 in the wall of the cylinder. The plunger 46 has a hook portion 49 adapted to bear against one wing of the valve 14. A spring 48 held in a recess 47 in the valve cover 18 presses against the plunger 46 which in turn presses against the hollow plunger 52, and makes a continuous connection between the spring 48 and the valve 35 so that rotation of the cam 45 of the valve 35 compresses or releases the'spring 48 and looks or releases'the valve 14.

When the valve 35 is in position for nor- I 45 presses against the base of the hollow rod 52 and forces it up into its passageway where it in turn lifts the plunger 46 against the compression of the spring 48 thereby leaving the distributor valve 14 free to operate.

In the blowing position, however, as shown in Figure 1 when the operator has turned the valve 35 to close the exhaust port 30, the cam 45 releases pressure upon the spring 48 which depresses the plunger 46 and brings the hook portion 49 down upon the edge of the valve 14 holding it firmly on its seat. The movement of the plunger 46 pushes the hollow rod 52 down so that the ports 54 register with the port 53 at"t he rear of the piston chamber. Y

Fluidcompressed by the up-stroke of the piston" 5 in the'piston chamber 7 leaks to atmosphere by wayof the port 53, the ports 54, the hollow rod 52, the bore 28 and the passage 44.

At the sametime fluid fromthe front end of the cylinder is forced alongthe flutes of the piston through the front cylinder washer 8, the chuck 9, and thence through the hollow drill steel 10 to the drill hole. v

I claim: 7

1. In a fluid actuated tool, the combination of a cylinder having inlet ports to the front and rear thereof, an exhaust port for the cylinder, a pistonin the cylindernormally controlling the exhaust port, a fluid supply port, a distributor valve to admit pressure fluid alternately to the front and rear inlet ports, a latch for closing the exhaust port and locking the distributor valve in one of its positions, a 1 spring to hold said latch in the locking position, a plunger to compress said spring dur ing normal operation I and manually con-' trolled means simultaneously to open the exhaust port and compress the said spring or to close the exhaust port and release said spring.

2. In, a fluid actuated tool, the combination of. a cylinder having inlet ports to the front and rear thereof,an exhaust port for the cylinder,-.a piston in the cylinder normally controlling'the exhaust port, a fluid supply port, a distributor valve to admit pressure fluid alternately to the front'and rear inlet ports, a latch to lock the distributor valve inoneof its positions, a spring to hold said latch in the 1 locking position, plunger in contact with said latch controlling a vent passage in oneend of the cylinder and manually controlled means simultaneously to open the exhaust port and release the latch or to close the exhaust port and release the spring. y

3. In a fluid actuated tool, the combination of a cylinder having inlet ports to the front and rear thereof, an exhaust port for the cylinder, a piston in the cylinder nor- -mally controlling the exhaust port, a fluid supply port, a distributor valve to admit pressure fluid alternately to'the front and rear inlet ports, a latch to lock the distributor specification.

THOMAS L. MURPHY.

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