US1968376A - Front end construction for rock drills - Google Patents

Description

July 31, 1934. J. c. CURTIS 1,963,376

FRONT END CONSTRUCTION FOR ROCK DRILLS Filed Sept. 26, 1931 [M /L5 0 76 7 40 30 zi' 27 M14 f JOHN 6. age 775 INVENTOR LQM ATTORNEY Patented July 31, 1934 v z FRONT END CONSTRUCTION FOR ROCK DRILLS John 0. Curtis, Cleveland, Ohio, assignor to The Cleveland Rock Drill Company, Cleveland, Ohio, a corporation of Ohio Application September 26, 1931, Serial No. 565328 2 Claims. (Cl. 121-32) This invention relates to rock drills but more the several views, the rock drill comprisesa-cylparticularly to the front bearing construction for inder 10 having reciprocabletherein a hammer 11 rock drills of the hammer type. being formed with an extension or stem 12. 'The Considerable trouble has been experienced with front cylinder is provided with an enlarged counrock drills having a hammer formed of differenterbore 13 disposed in axial alignment with the tial diameters. It has been found that due to main cylinder bore 14. Within the enlarged the'torque applied to the hammer during its rearcounterbore 13 and with a pressed fit engagement ward stroke, the hammer stem is forced radially therein, there is a sleeve or spacer 16 provided against its bearing. In the common practice, intermediate its ends with an external flange 1'7 that bearing is usually of the stationary type afheld in abutting relation with the outer endof fording a reciprocatory as well as a rotary bearthe cylinder and the outer end of the chuck ing for the hammer stem and is necessarily of a housing 18. Rotatably mounted within the rather short length to accommodate the other spacer 16, there is a bushing or chuck 19 having working parts of the mechanism. The torque its penetration therein limited byan external M applied on the hammer stem as well as its longiflange 20 abutting against the outer end of the 'tudinal displacement creates a frictional resistspacer 16 and being formed with a projection 21 ance which has the tendency to cause the scoring rotatably mounted within a bore 22 of 1 the chuck of the stem within its bearing. housing 18. The rearward end 23 of the chuck It is an object of this invention to provide a 191s adequately machined to slidably receive and i rock drill with adequate bearing means for the guide the hammer stem Band has its front end the invention. clamped by either the shoulder 31 or 30.

"- bols designate corresponding parts throughout alignmentwith the cylinder bore 14.

hammer stem thus overcoming the scoring of the provided with a plurality of inwardly prostem and therefore reducing the cost of operajecting ribs or flutes 24 capable of engagetion, ment with the splines 25 which are provided Another object of this invention is to provide on the hammer stem 12, preventing thereby arela rock drill with a readily removable hammer ative rotation of the chuck with the hammer. stem bearing thus overcoming the often encoun- Internally disposed within the projection 21, tered difficulty in replacing such a part which there is a plurality of flutes 26,.similar to the in usual construction is generally with a pressed flutes 24. Within the chuck housing bore 27, fitengagement within the front end of the cylthere is rotatably mounted therein a chuck jaw 30 inder. 28 formed with an external flange 29 havingone Other objects more or less ancillary to the foreor" its sides in abutting relation with a shoulder going and the manner in which the various ob- 30 formed at the intersection of the bore 21 with jects are attained reside in the specific constructhe bore 27. lhe other side of the flange 29 is tion and aggroupment of the elements'peculiar to capable of engagement with the outer end of the. this structure, as will become apparent from a chuck 19. The bore 21 is of sufficient depth to' more complete examination of this specification, allow an adequate clearance between the outer in the claims of which there are assembled certain end of the chuck l9 and the adjacent side of the specific combinations of parts and specific conchuck jaw flange 29, allowing thereby the rotation structions indicative of the scope and spirit of of the chuck l9 and chuck jaw 28 W t ut bei In the drawing which illustrates a preferred Circumferentiaily disposed on the end of the embodiment of the invention: chuck jaw 28, there is a plurality of splines 33 Fig. 1 is a longitudinal sectional view of the capable of engagement with the flutes 26 of the front end of a'rock drill, illustrating the invenchuck 19 to prevent the rotation of the chuck tion. 19 with respect to the chuck jaw 28. The for- 00 Fig. 2 is a cross sectional view taken on a plan ward end of the chuck jaw 28 is provided with a indicated by line 2-2 in Figure 1. plurality of jaws 34 engageable with the corre- Fig. 3 is a view similar to Fig. 2 but taken on spending jaws 35 of the chuck key 36 rotatably a plan indicated by line 3-3 in Figure 1. disposed within the front portion of the chuck 350 Fig. 4 is a front elevational view partly in housing bore 27 and maintained therein by the section, inwardly projecting flange 38. The key 36 is Fig. 5 is a view similar to Figure 1 illustrating manufactured to .allow the passage of the lug a modification of the invention. steel or tool 37 which is slidably but non-rotatably Referring to the drawing, in which like symmounted within the chuck jaw bore 39 in axial In the modification of the invention, (Fig. 5) the locking means for the chuck 19 and chuck jaw 28 is attained with a screw threaded socket 40 formed in the chuck 19 and a corresponding screw threaded plug 41 formed at the rearward end of the chuck jaw 28. It is obvious that a locking means similar to the jaws 34 and 35 could be used without departing from the spirit of the invention.

In the operation of the rock drill, the hammer 11 is reciprocated within the cylinder 10 by fluid pressure controlled by a valve mechanism of any suitable type. Toward the end of its rearward stroke, the hammer is delivering a blow to the steel or tool 38 driving consequently the tool into the substance being drilled. During its rearward stroke, the hammer 11 is subjected to a rotative movement impelled thereto by any suitable ratchet mechanism as commonly used in machines of this type. Obviously this rotative movement will be transmitted to the chuck 19 by the engagement of the hammer splines 25 with the flutes 24 and to the drill steel 38 by the engagement of the flutes 26 with the splines 33.

Heretofore in devices of this character, the piston stem 12 was reciprocatively mounted within a short stationary bushing which had the difliculty of maintaining an exact axial alignment of the stem 12 with the cylinder bore 14 and consequently increasing the frictional resistance within said bushing and censequently scoring the stem 12. In this improved construction, the guiding bushing for the hammer stem 12 is rotatably mounted within a long and eflicient spacer 16. The torque imparted to the hammer is distributed on the full exterior surface of the chuck 19 which can be made of softer material than the spacer 16. The chuck 19 may for instance be manufactured of brass, thus preventing any noticeable wear within the spacer 16 and overcoming thereby the difiicult replacement of that spacer from its pressed fitted engagement with the cylinder.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. In a rock drill, the combination with a cylinder having a fluid actuated hammer reciprocable therein and capable of rotation responsive to its reciprocation, said piston being formed with a head and a stern, external splines on the front end portion of said stem, of a stationary removable bushing within said cylinder, of a sleeved member rotatable within the entire length of said bushing through which said piston stem is free to slide, of a front housing, of a chuck member rotatable within said housing formed with external splines disposed on the rear end portion thereof, a duality of sets of internal splines within said sleeved member, one of said sets of splines being capable of interengagement with the splines of said piston stern and the other of said sets of splines being capable of interengagement with the splines of said chuck member for transmitting the rotation of said piston to said sleeved and chuck members, an internal portion of said sleeved member being engageable with the unsplined portion of said piston stem for guiding the latter in axial alignment with said cylinder and taking the wear resulting therefrom, the external circumferential wall of said sleeved member 00- operating with the external wall of said bushing for taking the wear resulting from the rotation of said piston.

2. In a rock drill, the combination with a cylinder having a fluid actuated hammer reciprocable therein and capable of rotation responsive to its reciprocation, said piston being formed with a head and stem, of a stationary removable bushing within said cylinder, of a sleeved member rotatable within the entire length of said bushings through which said piston stem is free to slide, external splines disposed Within the front end portion of said piston stem, internal splines disposed within the middle portion of said sleeve member capable of interengagement with the rotation of the latter to the former, a rotatable chuck member formed with external splines engageable with other internal splines provided within the front end portion of said sleeved member for transmitting the rotation of the latter to said chuck member, the rearward internal portion of said sleeved member being engageable with the corresponding portion of said piston stem for guiding the latter in axial alignment I with said cylinder and taking the wear resulting therefrom, the external circumferential wall of said sleeved member cooperating with the internal wall of said bushing for taking the wear resulting from the rotation of said piston, the rear 7 end of said sleeved member being exposed to the pressure fluid admitted on the front end of said piston head during the actuation of the latter, the area of the exposed end of said sleeved member being less than that of the front of said piston head.

JOHN C. CURTIS.

splines of said piston stem for transmitting the

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