US2236121A - Implement retainer - Google Patents

Description

March 25, 1941. G. G. TUTTLE V Filed sept. 153s 54 I J 54' mlm'/ff Il 37 J I J wf 1 %ff 56 ff f 0 ,Il

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Patented Mar. 25, 1941 UNITED STATES PATENT OFFICE IMPLEMENT RETAINER n Application September 28, 1938,\Serial No. 232,057

4 Claims.

This invention relates to rock drills, .and more particularly to-implement retainers for rockdrills of the hammer type in which the working implement is capable of free reciprocation with respect to the piston whereby it is actuated.

One object of the invention is to prevent ejection of a working implement from the percussive tool whereby it is actuated.

Another object is to arrange the retainer enrely within the percussive tool casing and thereby prevent the retainer from contacting with the work and becoming damaged as a result.

Still another object is to enable the retainer to be conveniently placed in the retaining and non-retaining positions.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is an elevation, partly in section, of the front end portion of a percussive tool or rock drill equipped with a retainer constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure l on the line 2-2 looking in the direction indicated by the arrows, and

Figure 3 is a side elevation of the front end of the rock drill.

Referring more particularly to the drawing, 20 designates the front head of a rock drill and 2| a bore in the front head comprising enlarged and reduced portions 22 and 23 containing a bushing 35 24. The part of the bushing 24 lying in the reduced portion 23 serves as a guide for a shank 25 of a working implement 26, and the rearward or enlarged portion of the bushing 24 may serve as the guide for a hammer piston 21 r-eciprocable in the rock drill for delivering blows to the shank of the working implement.

The working implement may be in the form of a drill steel, and at the juncture of its body portion with the shank 25 is a collar 28 which lies in the reduced portion 23 of the bore 2| and abuts the front end of the bushing 2'4 to limit the distance which the working implement may extend into the rock drill.

The steel retainer, constructed in accordance 50 with the practice of the invention, is arranged relatively within the front end of the rock drill. It is in the form of a plate 29 having an aperture 30 through which the working implement -26 eX- tends. The retainer 29 may bear directly against the front end surface 3| of the front head and lies in a recess 32 within a cap 33 attached to the front head by bolts 34.

The retainer 29 is supported by the bottom surface 35 of the recess 32 upon which it is slidable. It is guided at its sides by surfaces 36 of lugs 3l on the front head 2,0 lying on opposite sides of the cap 33' to hold the cap against rotary movement with respect to the frontvhead.

The retainer is so proportioned that it is capable of some degree of slidable movement in the recess 32 and on one end of the retainer is a flat surface 38 which serves as a bearing surface for a pin 39 arranged eccentrically on a shaft 40 rotatable in the front head 21|. The shaft 40, which extends longitudinally of the rock drill, is arranged in an enlargement 4| on the side of the front head and carries a reduced extension 42 that projects exteriorly of the enlargement -4| to receive a lever 43 whereby the shaft may be manually rotated to the positions required for actuating the retainer 29. The lever 43 is secured to the extension 42 by a nut 44, and any suitable means (not shown) may be provided for holding the shaft 40 in its limiting positions.

On the side or end of the retainer opposite to the surface 38 are seating surfaces 45 for springs 46 extending into sockets 41 in the cap 33 to actuate the retainer 29 into position for releasing the working implement upon movement of the shaft 40 to rock the pin 39 out of engagement with the retainer.

During the operation of the device, the retainer 29 occupies a position, illustrated in Figures 1 and 2, in which the aperture 3|) lies eccentrically with respect to the collar 28 of the working implement and will be held there by the pin 39. A portion of the retainer adjacent the aperture 30 will then lie in the path of the collar 28 to act as an abutment therefor in the event that the working implement is projected forwardly beyond its normal range of movement.

Whenever it is intended to remove the working implement the shaft 40 is rotated through an arc of approximately and the pin 39 is thereby moved out of contact with the flat surface 38. 'Ihe springs 46 will then move the retainer toward the shaft 40 and into a position in which the aperture 30 will be -aligned coaxially with the bore 2|. The working implement 26 may then be withdrawn from the front head and through the retainer, it being understood, of course, that the aperture 30 is of a diameter that will permit the collar 28 to pass readily therethrough.

I claim:

1. In an implement retainer for percussive tools,

the combination of a casing and a Working implement in the casing having a collar, a retainer lying entirely Within the casing having an aperture to permit the passage of the collar therethrough, a manually rotatable shaft on the front head, means eccentrically mounted on the shaft movable upon rotation of the shaft for moving the retainer into and holding it in the path of the coll-ar, and resilient means for moving the retainer into positions to bring the aperture into coaxial alignment with the collar.

2. In an implement retainer for percussive tools, the combination of a front head and a Working implement therein having a collar, a cap .on the end of the front head having a recess, a retainer in the form of a plate slidable in and lying entirely Within the recess and having an aperture to receive the Working implement, a manually rotatable shaft on the front head, means eccentrically mounted on the shaft movable upon rotation of the shaft for moving the retainer into the path of the collar, and a spring to move the retainer into position to bring the aperture into coaxial alignment with the collar.

3. In an implement retainer for percussive tools, the combination of a front head and a Working implement therein having a collar, a cap on the end of the front head having a recess, guide surfaces on the front head and the cap, a retainer lying entirely Within the recess slidable on the guide surfaces and having an aperture to receive the Working implement, a manually rotatable shaft on the front head, a pin eccentrically mounted on the shaft for moving the retainer into the path of the collar upon rotation of the shaft, and a spring for returning the retainer to bring the aperture into coaxial alignment with the collar.

4. In an implement retainer :for percussive tools, the combination of a front head and a Working implement therein having a collar, a cap on the end of the front head having a recess, means on the front head interlockingly engaging the cap to prevent relative rotary movement between the cap and the front head, guide suriaces on the front head and the cap, a retainer lying entirely Within the recess slidable on the guide surfaces and having an aperture to receive the Working implement yand to permit the passage of the collar therethrough, a shaft on the front head, a pin eccentrically mounted on the shaft and bearing against the retainer, means to rotate the shaft and move the pin for moving the retainer into and holding it in the path of the collar, and a spring for returning the retainer to bring the aperture into coaxial alignment With the collar.

GRGVER G. TUTTLE.

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