US1798257A - Front head for rock drills - Google Patents

Description

March 31, 1931. c. c. HANSEN 1,798,257

FRONT HEAD FOR ROCK DRILLS Filed Sept. 23, 1926 IN VEN TOR r e 12881: Egg f I s I,

fi/J" AT ORNEY Patented Mar. 31, 1931 .Frrcr.

PATENT CHARLES'C. HANSEN, OF EAS'ION, PENNSYLVANIA; ASSIGNOR TO INGEBSOLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A GORPOBATION OF NEXV JERSEY FRONT HEAD FOB ROCK D RILLS Application filed September 23, 1926.

This invention relates to rock drills and more particularly to front head constructions providing renewable wearing members.

In certain types of rock drills and more particularly rock drills for drilling up-holes, the drill is rotated by hand. In such drills the drill steel is chucked to the front head to rotate with the drill. The usual practice has been to provide square shanks on the drill steels and square holes in the front heads for the drill steels to fit into. When the front head became worn badly it was the usual practice to replace the front head. Parts such as the front head must be capable of withstanding hard usage and to this end they have usually been made of case hardened material. The case hardening is adapted to withstand the wear but as soon as the case becomes worn through the wear is very rapid and the front head must be replaced. Due to the treatment in manufacture and the material of which the front heads are made, these parts are expensive and contribute considerably to the cost of upkeep of 115 the tool. It is an obiect of this invention to enable front heads of drills of the type described to be used indefinitely by providing renewable wearing parts.

Other objects and advantages of the inpointed out hereinafter.

In the drawing in which similar reference characters refer to similar parts.

Figure 1 shows a preferred embodiment of 1:5 the invention as applied to a rock drill, the view being taken in longitudinal section and only the forward parts of the rock drill being shown,

Figure 2 is a cross section through the front head taken along the line 2-2 of Fig. 1, looking in the direction of the arrows, Figure 3 is a cross section of a rock drill front head provided with an alternative arrangement and embodiment of the inven- 115 tion Figure 4 is a cross sectional view of the front head of a rock drill provided with a second alternative arrangement and embodiment of the invention, and

Figure 5 is a cross section of the front Serial No. 137,300.

headof a rock drill showing a third alternative arrangement and embodiment of the invention. 7

Referring to the drawings and more particularly to Figs. 1 and 2, the rock drill includes a cylinder A within which a reciprocatory' hammer piston B is adapted to strike an anvil block C mounted in an anvil block seat D supported at the front end of the cylinder A. The front head E of the rock drill a may be attached in any suitable manner to the anvil block seat-D, there being an anvil block washer F interposed therebetween.

The front head E is adapted to grip and transmit rotation to the shank of a drill bearing pressure of the drill steel exists at the corners and, consequently, the most wear will occur at the surface bearing against such corners. In order that the bearlng surfaces may be renewed when worn out, such surfaces are provided in this embodiment by long rods H insertable in cylindrical holes K- located .in square formation in the front head E. so vention will be in part obvious and in part Flat surfaces K extend transversely between. the holes K and lie. in planes extending through the axes of the holes. Rectangular recesses H are formed in the rods H, and the surfaces of the recesses coincide with the flat surfaces K to form a square-hole J similar insize to the section of the drill steel.

The holes K may be tapered, ifdesired, to cause the rods H to bind as they are driven into place. Preferably the rods H are, as

shown, adapted to fit snugly in the bores of driven out in any suitable manner and re placed.

The upkeep of the tool due to wear on the front head is relatively low since the cost of manufacture of the rods H is small as well as the cost of inserting them in the front head E. The front head E will last indefinitely. In the alternative arrangement shown in Fig. 3, the front head E is provided with an aperture J having two rods L adapted to bear against each corner of the drill steel shank G. To this end the front head E is provided with eight bores O entering the aperture J and adapted to receive the rods L. Flat surfaces L are provided on the rods L to lie flush with the surfaces of the aperture J for forming a square hole to receive the drill steel shank G. The rods L are simpler to construct than the rods H since it is necessary merely to grind the flat surfaces L 011 one face instead of the notch provided in the rods H. In some cases it is found that the wear occurs in only one direction of the drill steel G and in such cases a construction may he provided as shown in Fig. 4, in which the aperture J 2 is broached at each corner as at P to receive a rectangular rod Q, the flat face Q, of which is adapted to bear against the corner of the drill steel shank G.

Similarly, as shown in Fig. 5, the aperture J may he provided with bores R adjacent each corner of the shank of the drill steel G to receive cylindrical rods S having fiat surfaces S on one side which lie flush with the surfaces of the aperture J 3 and hear against the corners of the drill steel shank G in a manner similar to the rods Q, as shown in Fig. 4. It may be simpler to hold the rods S in place in cylindrical bores R than to support the rectangular rods Q, in the broached apertures P.

I claim:

A front head construction for a rock drill comprising a front head having four tapered cylindrical holes arranged in parallelism and in square formation, said holes opening at the opposite ends of the front head, flat surfaces between adjacent holes lying in planes extending through the axes of adjacent holes, cylindrical wearing rods snugly fitted in the holes, and angular recesses in the rods having surfaces coinciding with the flat surfaces to form a square aperture. the surfaces of said recesses being held in alignment with the flat surfaces by the frictional engagen'ient of the rods with the walls of the holes.

In testimony whereof I have signed this specification.

CHARLES C. HANSEN.

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