US1355175A - Percussive tool - Google Patents

Description

W. A. SMITH.

PERCUSS WE TOOL.

APPLICATION FILED APR 19, 1918.

f 55,175. Patented Oct. 12,1920.

IN V EN TOR.

WA/ ATTO NEYS.

UNITED STATES PATENT orrtca WILLIAM A. SMITH, or EASTON, rnnnsrnvnivra, r-issrsnoa ro INGEBSQLL-RAEZ) COMPANY, OF JERSEY CITY, NEW JnRsn'r, a oonrcnnriou or new JERSEY.

PERCUSSIVE TOOL.

Application filed April 19,

To all whom it may concern:

Be it known that I, WILLIAM A. SMITH, a citizen of the United States, residing at Easton, in the county of Northampton and State of Pennsylvania, have invented a certain new and useful Improvement in Percussive Tools, of which the following is a specification.

This invention relates to percussive tools I and in particular to a percussive tool of the differential piston type adapted for harnmer drills.

The objects of the present invention are to provide a fluid operated percussive tool 1n which the piston is reciprocated forwardly and backwardly by means of fluid pressure supplied intermittently to three pressure surfaces, two operating to thrust the piston forwardly and one operating to return it; a further object being to provide conduits for supplying the fluid to the three pressure surfaces which will supply the fluid at the proper points of the travel of the piston, and which will quickly supply maximum pressure to the pressure areas so that the hammer drill will operate efficiently and strike a heavy powerful blow at the end of its forward stroke.

With these and other objects in view, I have devised the construction a specific embodiment of which is represented in the accompanying drawings and set forth in the following specification:

In the drawings annexed hereto and formin a part hereof:

I igure '1 shows a cross sectional view of a hammer drill made in accordance with the present invention in which the piston is shown at approximately midstroke, and

Fig. 2, shows a similiar view of the hammer drill with the piston in striking position at the end of its forward stroke.

Referring more particularly to the drawings, the cylinder is shown at 1 having a large central bore 2 and a smaller bore 3 at its rear end, and in which reciprocates a piston 1. The piston 4 is shown of the differential type having a central head 5 and shanks extending from either side face thereof, respectively, 6 and 7. As shown in the drawings, the piston is symmetrical and therefore reversible but this feature forms no part of the present invention, but my present invention is adapted to this form of piston. The fluid supplied to the Specification of Letters Patent. Pgmj gnt d 0 1; 12 ggqp 151%. Serial No. 229,622.

tool is admitted at 8 and through the short condult or supply passage 9 to an annular recess 10 cut into the smaller bore 3 of the cylinder 1. Another annular recess 11 cut into the smaller bore 3 of the cylinder 1 is connected to a conduit 12 which opens into the rear end of the smaller bore 8 at 13 and also into the rear end of the larger bore 2 as shown at 14. From the above it will be seen that conduit 12 provides a passage for admitting fluid to portions of the cylinder 1 to exert pressure against two pressure areas of thepiston to drive the piston 4 forwardly.

A conduit 15 is further provided intercepting the smaller bore 3 at 16 and the larger bore 2 at 17 which will provide a passage for supplying fluid to return the piston to its rearward position. To open connection between the fluid supply 8 and the conduits 12 and 15, the shank 6 of the plston 4: is provided with a neck or reduced portion 18. In the position shown in Fig. l of the drawings the neck portion 18 is shown in its position to open the conduit 12 to the admission port 10 admitting fluid to force the piston forwardly, while in Fig. 2 is shown the position of the piston to open the connection between the admision port 11 and conduit 15 to return the piston.

For convenience, and to permit the piston 4; to be reversed, an extra neck portion 19 is provided in shank 7 to permit the piston at to function when in its reversed position. In the position of the piston as shown the neck portion 19 performs no function.

At the forward end of the cylinder 1 is provided the usual front head 20 and spacing member 21 within which is located the chuck 22 and within the chuck 22 is housed the drill steel 23 which may be rotated with the chuck 22 in any suitable manner, (not shown).

It is to be understood that the present showing and description disclose only one specific embodiment of the present invention, and that other forms and modifications are included within the spirit and scope of the invention, as expressed in th appended claim.

What I claim is:

In a fluid operated percussive tool, the combination of a cylinder having bores of different diameters, a fluid conduit extending from a point in the smaller bore to the forward end of the larger bore, another intermediate of the points of connection of the said two fluid conduits with said smaller 10 bore, a piston in said cylinder having a head fitting the larger bore and a shank fitting the smaller bore, a reduced neck in the rear- Ward portion of saidshank adapted to ali V ternately establish communication between the said supply passage and the said fluid 1 conduits leading to the ends of the cylinder,

and exhaust means for the cylinder.

In testlmony whereof, I have hereunto set my hand.

WILLIAM A. SMITH.

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