Патент USA US2117810код для вставки
May 17, 1938. E. B. Lr-:AR l2,117,810 ROCK DRILL WITH BLOWING DEVICE Filed June 5, 193s s sheets-sheet 1 Nw.. INVENTOR May 17, 1938. E. B. LEAR u 2,117,810 ROCK DRILL WITH BLOWING DEVICE Filed June 3, 1936 3 Sheets-Sheet 2 INVENTOR B ATTO R N EY May 17, 193s. E. B. LEAR 2,117,810 . ROCK DRILL WITH BLOWING DEVICE Filed June 5, 195s ' 49 s sheets-sheet s "X ATTORNEY 2,117,810 Patented May 17, 1938 VVUNITE-D 'STATES 2,117,810 ROCK DRILL WITH BLOWING DEVICE Earl B. Lear, Detroit, Mich., assignor to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey 'Application June 3, 1936, .Serial No. 83,210 1 Claim. The present invention relates to fluid pressure operated percussive tools, such as rock drills, and is concerned particularly with the throttle .and D (Cl. 121-40) and associated ports, the valve being arranged in the ori-position; »distributing valves for such tools. Among the objects of the invention are to reduce the manufacturing cost and weight of a rock drill and to insure positive hole cleaning. Accordingly, a throttle Valve and a blower valve are combined into a unitary structure so ar ie ranged that each time the throttle valve is turned on or off a stream of air is directed through the bore in the drill steel to remove the detritus from the hole. The throttle valve is so constructed thatit closes the central exhaust port for the l5 cylinder whenever the throttle valve is in either the blowing or closed position to prevent the admissionA of dirt through the exhaust port to the cylinder bore. A feature of the invention resides in fluid pres sure means for holding the distributing valve immovable against one of its seats to admit compressed air to the rear end of the cylinder bore from whence the air is conducted through the hollow piston to the drill steel bore with a Vminimum of leakage. The means for holding the distributing valve in position comprises ports in a manipulative throttle valve, one of which admits live air lto one face of the distributing valve and another of which exhausts the oppos ingY face of the distributing valve. Another object ofthe invention is the pro vision of a distributing valve of the disc Atype having means for centering the valve relative to its seats and for prolonging the life of the valve. The vdistributing valve is in the form of a disc perforated to receive a bushing and'having a hub adapted to fit the bushing and guide the valve in its movement. Other objects and features of the invention will appear more clearly from the accompanying `drawings and appended claim. In the drawings which illustrat e one embodi ment of the invention: Fig. 1 is an elevation of a portion of a rock drill ofthe sinker type, the throttle valve handle being shown in drilling position; Fig. 2 is a section through the plane indicated by the arrows 2-2 in Figs. 1 and 6; Fig. 3 is a view similar to Fig. 2 but partly in elevation .and partly schematic and showing the combined throttle and blower valve in blowing position; Y Fig. 4l isa fragmentary schematic view show ing two‘diiierentsections of the throttle valve ^ Fig. 5 is a View similar to Fig. 4 but with the throttle valve> adjusted to the drilling position; Fig. 6 is an end elevation looking from left 5 toward right in Fig. 1; Fig. '7 is a cross-section as. indicated by the arrows l-'I in Fig. 1, but with the throttle valve in blowing position; Fig. 8 is a fragmentary longitudinal section showing the cylinder, piston and distributing valve,- certain passages being, for convenience, shown in simplified form; Fig. 9 is a fragmentary longitudinal sectional view on an enlarged scale showing the distribu 15 ting Valve and valve chest, and Fig. 10 is a sectional view of the distributing valve on the same scale as Fig. 9. The rock drill illustrated in the drawings com prises a cylinder II having a piston I2 recip 20 rocably mounted therein. The forward part of the piston has a grooved extension I3 which passes through a front cylinder washer I4 and into fluted engagement with an internally grooved chuck nut I5 which is’keyed to a chuck i6. The washer I4 forms a closure for the front end of the cylinder. At the end of its forward stroke the piston strikes the drill steel I1 having a non-circular ñt with the chuck. The chuck nut I5, chuck I6, and washer I4 are held in posi 30 tion by means of a iront head I9 which may be fastened to the cylinder by any suitable means, such asA elongated bolts I8 shown in Figs. l, 6 and '7. The rear of the cylinder II is closed by a back cylinder’washer 20 which cooperates with a valve case 2l to form a housing for a distributing valve 22. A ratchet ring 23 is. positioned between the valve case and a backhead 24, the backhead be ing adapted to seat the heads Ißa of the bolts I8. The backhead is provided with arms 25 for supporting a grip handle 26. A plate 2l at the rear end of the ratchet ring cooperates with the backhead 24 to provide a lubricant reservoir. 28. Any suitable means may be provided for ro* 45 tating the piston I2 step-by-step as it recipro cates. As shown, the rotating mechanism com prises a riiie nut Sil screwed to the piston, a rifle bar _3l spirally splined to the nut, and pawls 32 carried by the head of the riñe bar and engageable with the internally toothed ratchet ring 23. A bushingf33, surrounding the rifle bar, provides a support for valve 22. The distributing valve 22 is shown most clearly in Figs. 9‘and 10. It comprises a disk portion.35 » 55 2,117,810 and a hub 3’6 integral therewith. The forward face of the disc portion is a plane surface adapted to rest on one or the other of the seats 31]c and 311* formed on the member 20. Valve seats 313‘ and 317’ are ñat and angularly disposed relative to each other so that the planes of the seats diverge forwardly. The seats have recesses 38]c and 38T. A port 40 connects the recess 38T with the rear end of the cylinder and a passage 4| connects recess 38j with the front end of the cylinder thereby to admit live pressure fluid al ternately to opposite sides of the piston head I2. The interior of the hub 35 is deñned by frusto conical surfaces 36a and 351), the included angle 15 between such surfaces being equal to the included angle between the seatsl 31j and 317’ so that the interior of the hub embraces. the bushing 33 on opposite sides when the disc portion 35 rests on either seat. The upper edge 35e of the hub is 20 bevelled to iit the adjacent portion of the valve chest 2|. The hub 36 guides the valve in its movement, permits rapid tripping of the valve and prolongs the life of the same. The hub also cen ters the valve with respect to Vits seats and as 25 sociated passages and thereby insures an adequate supply of pressure fluid with minimum leakage. The valve 22 is free to be oriented about its axis to distribute wear. 30 When the machine is conditioned for drilling, the operation is as follows: Live air is admitted (by throttle means hereinafter described) to a cham ber 43 in the valve housing 253, 2i, the rear face of the distributing valve 22 being exposed to pres sure fluid in said chamber. Assuming the dis 35 tributing valve and piston occupy the position shown in Figs. 8 and 9, live air passes around the peripheral edge of the valve disc portion 35 over the seat 31T and through recess 381“ and port 4|! to the rear end of the cylinder, thereby forcing 40 the- piston l2 forwardly. The air in front of the piston head I2 is vented through exhaust port 44 until the piston head has covered the exhaust port. The piston continues moving forward un der its momentum and delivers a blow to the drill steel l1. Toward the end of the forward stroke of the piston the valve is tripped to the position shown in Fig. 2 by the combined action of a re duction in pressure in the recess 38T caused by the uncovering of the exhaust port 44, and the building up of pressure at the front end of the cylinder due to the compression of air trapped in front of the piston head I2 which is trans mitted to the recess 38]c by means of passage 4|. After the valve has been tripped, live pressure fluid from chamber 43 passes around the periph eral edge of the distributing valve over seat 31j and through recess 38j and passage 4| to the front end of the cylinder || to force the pis ton rearwardly. The air at the rear end of the 60 cylinder is first exhausted through port 44 and then compressed aftery the piston head covers the exhaust port. When the front edge of the piston head uncovers the exhaust port, the drop in pressure at the front end of the 65 cylinder causes a corresponding reduction in pres sure in the recess 38f which, together with the increase of pressure in recess 381", is effective to trip the valve to the position shown in Fig. 9, thus completing a cycle of operation. It is desirable to provide means for blowing a stream of live air through the drill steel I1 to clear the bore hole of accumulated detritus. Ac cordingly, the invention comprises a blowing ar rangement which is operable whenever the throt tle valve is turned on or 01T and which does not require the manipulation of any device other than the throttle valve. The throttle valve 45, as shown in Fig. 7, is gen erally of frusto-conical shape to fit a correspond ingly shaped bore in a projection 46 on the out side of the cylinder ||. A handle 41, having an extension on the valve, is keyed thereto at 48 and is retained by a nut 49 threaded on the extremity of the throttle valve. A spring-pressed detent 50 carried by the handle is adapted to register with l0 any one of three depressions 5| on the cylinder projection 46 for yieldingly locking the handle and valve in selected position of adjustment. A sleeve 53 threaded to the cylinder projection 46, provides a retainer for an air supply hose 54 15 which communicates with recess 55 in the throttle valve. As shown in Figs. 3, 4 and 5, the live air recess 55 communicates with two- ports in the throttle valve 45 adapted selectively to admit pressure 20 fluid to passage 51 leading to the supply chamber 4S in the distributing valve housing 20, 2|. One of these ports 58 registers with passage 51 in the drilling position and the other port 59 registers in the blowing position. The throttle valve 45 has a 25 groove Eil out oi’ communication with the live air recess 55 and positioned to connect the main ex haust port 44 with the exhaust port 6| in the pro jection 46 when the throttle valve is adjusted to drilling position. A supplementary groove 60a 30 establishes communication between exhaust port 6| and a passage 63 leading to recess 38j in the distributing valve housing 2l to vent the recess when the throttle valve is adjusted to blowing 35 position. When the throttle handle 41 is in the drilling position, shown in Figs. 1 and 2, live air is sup plied to the distributing valve case 2| through port 58 in the throttle valve and passage 51 in the cylinder. At the same time the central ex 40 haust port 44 in the cylinder is vented through groove 65 in the throttle valve. In order to stop the operation of the machine, the throttle han dle 41 must first be turned to the blowing posi tion shown in Figs. 3 and 7. In this position, the 45 throttle valve supplies live air to the distributing valve chamber 43 by means of port 59` and pas sage 51. Simultaneously the central exhaust port 44 in the cylinder is closed by the throttle valve, and the recess 38j, facing one side of the dis 50 tributing valve, is vented through cylinder pas sage 63 and throttle valve -grooves 60a and 60. The preponderance of pressure on the rear face of that portion oi the distributing valve which overlies recess 38j moves the valve to the position 55 shown in Fig. 9 and holds the valve against seat 31j to admit live pressure ñuid through port 40 to the rear end of the cylinder. The pressure fluid admitted through port 4|) drives the piston forwardly until it is stopped by engagement with 60 the drill steel. Pressure ñuid in back of the piston passes through the clearance between the splines on the rifle bar 3| and riñe nut 30 and through the interior of the hollow piston and drill steel to 65 blow the detritus from the bore hole. When the valve handle 41 is adjusted to the off position, the live air recess 55 in the throttle valve is cut off from communication with the cylinder passages, and the main exhaust port 44 in the cylinder is 70 closed to prevent the admission of dust to the interior of the cylinder. What is claimed is: A fluid actuated rock drill comprising a cylin der, a hollow piston reciprocating therein, a hol 75 2,117,810 3 low drill steel adapted to receive blows from the piston, a distributing valve chest, passages leading from said chest to the respective ends of the cylinder, a main exhaust port for the cylinder, a supplementary exhaust port for the front end of the cylinder, a fluid pressure supply chamber in the valve chest, a distributing valve in the chest valve, a manipulative throttle valve mounted therein, characterized in that said throttle valve and housing are provided with selectively operable means for venting either exhaust port and simultaneously closing the other exhaust port, controlling communication between said supply and the supply chamber in the distributing valve 10 chest. chamber and said passages, a source of live pres sure fluid, connections between said source and said supply chamber, a housing for a throttle and vice versa, and are provided with selectively operable means for opening and closing the con nections between the source of live pressure fluid EARL B. LEAR.