US1056170A - Stroke-shortening device for percussive tools. - Google Patents

Description

C. O. HANSEN. STROKE SHORTENING DEVICE FOR PERCUSSIVBTOOLS.

APPLIOATION FILED MAY 31, 1912 1,056, 170.

Patented Man 18. 1913.

- piston 12 rotated b a unrrnn sra'ras r arianir orrrca.

CHARLES C. HANSEN, 0F EASTON, PENNSYLVANIA, ASSIGNOR. TO INGEBSOLL-RAND GQMPANY, OF NEW YORK. N. Y., A CORPORATION OF NEW JERSEY.

STROKE-SHORTENING DEVICE FOR PERGUSSIVE TOOLS.

To all whom it may concern:

Be it known that I, CHARLES C. HANSEN, a citizen of the l nited States, residing in Easton. in the county of Northampton and State of Pennsylvania, have invented certain new and useful Improvements in Stroke-Shortening Devices for Percussive Tools, of which the following is a specification.

This invention relates to percussive tools and more particularly to a stroke shortening or cushioning device for such tools.

The object of this invention is to provide a simple and effective means for shortening the stroke of percussive tools, especially drills. under conditions which require short stroking such as in starting oblique holes in rock faces and in drilling in soft rock.

lVith this object in view I have devised a mechanism a practical embodiment of which is shown in the accompanying drawings in which l V Figure 1 is a. longitudinalsection through the drill embodying the device. Fig. 2 is a transverse section on the line 1IH of Fig. 1 and El a side elevation showing the handle for operating the stroke shortening mechanism.

' The device as shown is embodied in a rock drill of ordinary construction which comprises a cylinder 1 in which reciprocates a & ritie bar 3. The valve iis of the balanced wing type one of its wings controlling the. inlet passages 5 and 6 leading respectively to the back and front end of the cylinder and the other of its wings controlling the corresponding exhaust passages 7 and S. Operating fluid is admitted by the inlet opening 9 and exhausts through the outlet 10, the valve being thrown by compression in the inlet passages produced by the piston atter'it has overrun the exhaust ports.

In the exhaust passage 7 is the stroke shortening valve which consists of plate 11 so'shaped as to closely tit the passage 7 when turned in a position transversely across the passage shown in Fig. -1. Through the plate is an perturelQ which is of small area in comparison to the size of the passage.

One edge of the plate 11 is provided with a.

cylindrlcal lu 13 seated for rotation in a depression in the face of the passage while on theopposite edge or the plate 11 is a Specification of Letters Patent.

Patented Mar. 18, 1913 Application filed May 31, 1912. Serial No. 700,634.

shank it which rotates in bushing 15 threaded into the valve chest casting. Secured to the outer end of the shank 14 is a handle 16 provided with a rearwardly extended lug 17 in which slides a spring pressed pin-18 adapted to be seated at will in either of the depressions'lt) and 20. v

The operation of the device is evident from the description. When the plate 11 is in the position shown by the dotted lines in Fig. 1 the fluid from the back end of the cylinder will exhaust freely through the passage 7 and outlet 10. lVhen however the plate 11 is in the position shown by the full lines'ot Fig. 1 the fluid from the back end of the cylinder will exhaust only through the aperture 12 which will cushion the hack stroke of the piston toa considerable extent thus causing the valve to be thrown sooner and hence shortening the effective stroke of the piston.

Although the device as shown is applied to a rock drill it is adapted for use with any type of percussive tool. It is however particularly adapted to valves of the type shown wherein the valve is thrown by piston compression transmitted to the valve by the inlet passage.

l't is to be understood that'the device as shown and described discloses only one modification of the tool and-other changed and modified, forms are included within the spirit and scope of my invention as expressed in the claims.

Tv'hat l: claim is: g

1. In a percussive tool, acylinder, a piston therein. a valve, an inlet passage controlled by said valve, a separate exhaust; passage controlled by-said valve and an apertured plate mounted for rotation in said exhaust passage.

2. In a percussive tool. a cylinder a piston therein, a valve, an inlet passage controlled by said valve, a separate exhaust passage controlled by said valve. a plate ro tatahl-y mounted in said passage and tii 'ing said passage when transversely across it. an aperture in said plate, and means to rotate said plate' In a percussive tool, a cylinder, a piston therein, a valve, an inlet passage controlled by said valve, a separate exhaust passage controlled by said valve so placed as to allow piston compression in said inlet pas-

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