US2461530A

US2461530A - Rock drill

Info

Publication number: US2461530A
Application number: US493240A
Authority: US
Inventors: John C Curtis; Elmer G Gartin
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1943-07-02
Filing date: 1943-07-02
Publication date: 1949-02-15
Anticipated expiration: 1966-02-15

Description

. Feb. 15,1949. CURTIS ET AL 2,461,530

ROCK DRILL Fild July 2, 1943 2 Sheets-Sheet 2 n ,5// a 5 fr? r fifin 6 6212 2 215: 6 Z EJ222192 6 fiawiz'n.

by usual spring-pressed pawls 35 carried by a pawl carrier 36. This pawl carrier is integrally secured to a spirally grooved rifle bar 31 which extends forwardly into the rear end of the cylinder bore and engages a rifle nut 38 secured within the hammer piston. As the hammer piston moves forwardly to effect its working stroke, i. e. to strike a blow on the tappet 8, the pawls of the carrier slip over the ratchet teeth, thereby permitting unimpeded piston movement. Upon rearward movement of the hammer piston, the pawls engage the ratchet teeth to hold the rifle bar against rotation so that, due to the spiral groove interlocking connection, a' rotary motion is imparted to the piston, and this rotary motion is transmitted to the drill steel through the chuck. As is usual in rock drills of the type disclosed, cleansing liquid may be conducted to the drill steel bore to effect cleansing of the drill hole, and the tube provided for this purpose extends axially from the rear head block into the motor cylinder and through the hammer piston and tappet into the drill steel bore. In distinction from other constructions, the tube is a close sliding fit for the. openings in the impact member 6 and the striking block 8. During the drilling operation, the water emerging from the drill hole runs down over the'forward portion of the chuck, and the 4. chuck sleeve projection M is tapered at 55 (Fig. 5), and the front edge of the piston surrounding the bore i therein is chamfered or rounded-off at 5% so that during normal operation of the drilling motor the forward end of the hammer piston and the chuck sleeve projection never come into substantial contact, or if contact should occur, it would be relat-ively slight (see Fig. 2). Thus very little wear of the surfaces at 51' and 58 occurs during normal operation of the drill. Pressure fluid flowing from the cylinder bore through guard 24 directs the water and dirt over the chuck housing externally of the chuck. The tappet 8 is mounted for reciprocatory movement in a bore 40 in the chuck sleeve I 9, and the chuck sleeve has a reduced rearwardly proiecting portion 4| having a bore 42 which receives the body of the tappet in the manner shown. The tappet projects rearwardly. from the rear end of the chuck sleeve into a position to be struck by the hammer piston. Surrounding the rearward reduced portion M of the chuck sleeve within the driver sleeve i1 is an annular chamber 43 into which the forward end of the hammer piston is adapted to enter during its reciprocation as will later be explained.

The rear end of the cylinder'bore is closed by a rear head plate 44, and arranged between this headplate and the rear head member 32 is a valvechest d5 having a valve chamber containing a pair of cooperating relatively movable

fluid distributing valves

46 and 47. Carried by the rear head block 33 is a throttle valve 48 which may control the flow of pressure fluid through a supply passage 49 to the valve chamber internally of thevalves. Leading from the opposite ends of the valve chamber are

fluid supply'passages

56 and 5! for conducting pressure fluid, under the to, to the chamber 43 at the forward end of the hammer piston from the front end of the cylinder bore through the piston flutes to assist in returning the hammer piston after it delivers its impact blow to the tappet 8. Throwing

passages

53 and 5 controlled by the piston connect the cylinder bore with the valve chamber so that the valves may be thrown automatically into their different operating positions as the hammer piston reciprocates. This valve structure and the. fluid supply and throwing passages are described in the above mentioned copending application Serial No. 475,782.

The exterigr. of the rearward portion of the the piston flutes to the annular chamber 43 also enters the piston bore 1 at the rear of the chuck sleeve projection so that some cushioning of the piston movement takes place although comparatively little resistance to the forward movement of the piston is present at that time. Should the hammerpiston be driven forwardly into a more advanced forward position, for instance, in the event the drill steel strikes a pocket, the tappet is driven forwardly into the chuck sleeve bore as shown in Fig. 3 and the surfaces 51 and 58 (Fig. 5) move into, contact, thereby providing a seal and trapping the fluid in the piston bore to provide a substantial fluid cushion for the piston, thus preventing contact of theforward end of the piston with the chuck parts. Since during normal operation of the drilling motor little wear ofthe surfaces 5'! and 58 occurs, a relatively fluidtight seal is provided to prevent substantial fluid leakage from the cushion. Of course, there is no substantial loss of the cushion, both because of the maintained surface contact between the impact surface 5 and the rear end of the striking block 8, and because the close fits around the water tube would prevent serious leakage in the short times available, in any event. If the drill motor is run without a steel, the striking block may move up into contact with the inner end of the chuck bushing, and the forward end of the hammer motor piston may move forwardly almost into contact with the inner end of the chuck sleeve at its extremes of forward movement, and under these circumstances the close fits around the water tube will'safely maintain the necessary cushion pressure against escape.

As a result of this invention animproved chuck mechanism is-provided having a novel arrange ment of parts providing adequate bearing surfaces; whereby ruggedness and relatively long life of the parts are assured. By the provision of the novel dirt and water guard access of foreign matter to the chuck bearing surfaces is prevented. The improved drilling motor structure embodying the novel cushioning arrangement disclosed aflfords'" an improved and extremely effective cushioning of the hammer piston. Wear of the. sealing surfaces of the cushion is substantially form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without deetirsli i m s; .1. z

What we claim as new and desire to secure by 1. In a rock drill, a chuck mechanism for a drill steel comprising a chuck housing, a chuck sleeve rotatable in said housing, a chuck member detachably secured to said sleeve for rotation therewith and adapted to receive the shank of a drill steel, and a dirt and water guard rigidly clamped between said chuck sleeve and chuck member for rotation therewith and having portions enclosing the forward portions of said chuck sleeve and said housing.

2. In a rock drill, a chuck mechanism for a drill steel comprising a chuck housing, a chuck sleeve rotatable in said housing, a chuck member de tachably secured to said sleeve for rotation therewith and adapted to receive the shank of drill steel, and a dirt and water guard rigidly clamped between said sleeve and chuck member and enclosing the forward portion of said housing.

3. In a rock drill, a chuck mechanism for a drill steel comprising a chuck housing, a chuck sleeve rotatable in said housing, a chuck member detachably secured to said sleeve for rotation therewith and adapted to receive the shank of a drill steel, and a dirt and water guard having an annular flange clamped between said sleeve and chuck member and enclosing the forward porticn of said housing.

4. In a chuck mechanism for percussive rock drills, a driver sleeve having a reduced forward bore and an enlarged rearward bore, a chuck sleeve arranged in said front bore of said driver sleeve and having a portion projecting rearwardly into said rear bore, said chuck sleeve having a bore, a chuck member secured in said chuck sleeve bore and adapted to receive and support the shank of a drill steel, said chuck sleeve bore extending rearwardly of said chuck member, said chuck sleeve having a reduced portion projecting rearwardly into saidenlarged rearward bore, said rearwardly extending bore of said chuck sleeve and said reduced chuck sleeve portion adapted to receive and reciprocably guide a tappet for transmitting blows to the shank of the drill steel.

5. In a chuck mechanism for percussive rock drills, a driver sleeve having a bore, a chuck sleeve arranged in said sleeve bore and having a bore, a chuck member secured in said chuck sleeve bore and adapted to receive and support the shank of a drill steel, said chuck sleeve bore extending rearwardly of said chuck member, said chuck sleeve having a reduced projection extending rearwardly within said driver sleeve bore and having a reduced bore, said rearwardly extending bore of said chuck sleeve and said reduced bore in said rearward projection of said chuck sleeve adapted to receive and reciprocably guide a tappet for transmitting blows to the shank of the drill steel.

6. In a rock drill, a chuck mechanism for a drill steel comprising a chuck housing, a chuck sleeve rotatable in said housing and projecting outwardly from the forward end thereof, a chuck member secured to said sleeve for rotation therewith and adapted to receive the shank of a drill steel, said chuck member projecting forwardly from said sleeve, and a dirt and water guard enclosing the forward portions of said sleeve and housing, said guard having an inwardly directed annular flange rigidly clamped between the front end of said sleeve and said chuck member and providing a central opening through which said chuck member projects.

7. In a rock drill, a chuck mechanism for a drill steel comprising a chuck housing, a chuck sleeve rotatable in said housing and projectingoutwardly from the forward end thereof; a chuck member secured to said sleeve for rotation therewith and adapted to receive the shank of a drill steel, said chuck member projecting forwardly from said sieeve, and a dirt and water uard enclosing the forward portions of said sleeve and housing, said guard rigidly secured between said sleeve and chuck member and having stepped front and rear axial bores, the forward reduced bore receiving the forward portion of said sleeve and the rearward larger bore receiving the forward portion of said housing, and said guard having a front central opening of smaller diameter than said bores and through which said chuck member projects.

8. In a chuck mechanism, a chuck housing, a rotatable chuck sleeve journaled in said housing and projecting forwardly therefrom, a chuck member secured in said sleeve for rotation therewith and projecting forwardly from said sleeve, and a dirt and water guard enclosing the forward portion of said chuck housing and having an inwardly directed front annular flange surrounding said chuck member and rigidly clamped be tween said sleeve and said chuck member, said guard serving to prevent the access of dirt and water to the bearing between said sleeve and chuck housing. 7

9. In a chuck mechanism for percussive rock drills, a driver sleeve having stepped front and rear axial bores of whichsaid front bore is the smaller, a chuck sleeve secured in the smaller front bore of said driver sleeve, a chuck member secured in said chuck sleeve and adapted toreccive and support the shank of a drill steel, said chuck sleeve having a portion projecting rearwardly into the larger rear bore of said driver sleeve and having its outer periphery spaced inwardly from the walls of the larger bore to provide an annular chamber adapted to receive the annular front end of a hammer piston, said rearwardiy projecting portion of said chuck sleeve adapted to receive and reciprocably guide a tappet for transmitting the blows of the hammer piston to the drill steel shank.

19. A water and dirt guard for rock drills, comprising a circular guard body having alined stepped bores adapted to surround with a close running fit relatively rotatable parts of a rock drill chuck to provide a dirt seal, and having at one end an inwardly directed annular flange adapted to be clamped firmly between relatively adjustable rotatable parts of a drill chuck for rotation therewith.

JOHN C. CURTIS. ELMEPu G. GAR'I'IN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,408,691 Clark Mar. '7, 1922 1,551,096 Gartin Aug. 25, 1925 1,726,295 Gustafson Aug. 27, 1929 1.,74i8,021 Katterjohn Feb. 18, 1930 1,940,846 Curtis Dec. 26, 1933 2,255,423 Huffman Sept. 9, 1941