US1591377A - Broaching attachment for rock drills - Google Patents

Description

Patented July 6, 1926.

UNITED STATES.

PATENT OFFICE.

cnmns c. nausmw, or EASTON, PENNSYLVANIA, ASSIGNOR ro mennsoLn-nmm comm, or mnsnx our, NEW JERSEY, A conronnrrou or NEW'J'ERSEY.

rnoacnme arr'acnumrr ron nocx mamas.

Application fled November 11, 1925. Serial K036836313.

I This invention relates to rock drills, but

more particularly. to a breaching attachment for fluid actuated rock drills of the hammer type.

In quarrying slate, granite orsimilar rock formation, it is a common practice to remove the rock in the form of rectangular blocks. A convenient and practical method of sev-v ering such blocks from 'the mass is to drill l a line of holes, leaving a narrow wall of material between adjacent holes. The walls thus formed are then cut away by meansof a broach. This method of quarrying sym-- metrical blocksof rock has been found to be considerably more economical than it would be to form a cut with an ordinary drill steel. However, with the front heads heretofore used forbroaching operations it has been exceedingly difficult to prevent the broach from creeping away from the narrower section of'the wall between the holes to, the wider part. This obviously requires the removal of a greater amount of material and consequently increases the operating 'costs. 1

It is accordingly tion to enable a broaching tool to be rigidly guided and held against any tendency to depart from a desired course.

Another object is to construct abroaching attachment which may be quickly substituted for an ordinary rock drill front head and which will permit quick removal of the broaching tool from the attachment.

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

The invention consists of the combinations of elements, features of construction and arrangement *ofparts having the general mode of operation substantially as hereinafter descnbed and more particularly pointed out in the appended claims and illustrated in the accompanying drawin s, in which Figure 1 is an elevation o the front end of a rock drill equipped. with an attachment constructed inaccordance with the' invention with the guiding block removed inillustrating one of, its uses,

Figure 2 is an elevatlon partly in section taken through Figure 1 on the line 22 looking in the direction of the arrows,

' Figure 3 is a perspective view illustrating the manner in which the guide block may be removed from the attachment for the purpose of removing the breaching tool, and

an object of this inven- Figure 4 is .a transverse sectional view taken through Figure 2 on the line 4-4: looking in the direction of the arrows.

Referring to the drawings, the invention is shown embodied in a rock drill of which only a front portion of a cylinder A is shown. Within the cylinder A is a bushing B which acts as a guidefor a hammer piston C adapted to reciprocate therein to deliver blows to an anvil block D.

In accordance with the present invention, an attachment or a front head E is su ported by the cylinder A and preferab y secured thereto by means of a pair of cushioned side bolts. F which extend through lugs G and H of thecylinder A and the front head' E respectively. The bolts F are provided with springs J which serve to hold the front head E yieldably within the cylinder A, Nuts K screwed on the ends of the bolts F provide a seat for one end of the springs J and also serve as a means for adjusting the tension of said springs.

The front head E in this instance has a forwardly projectin cylindrical portion L to which is preferably secured integrally an extension 0 provided on its inner face P with a fiat cheek plate Q having a plane surface which in this instance serves as a guide 'for one face of a broaching tool R. 'f The check plate, Q'is preferably somewhat short-' er than the face P so that a shoulder S is ably equal to the combined, thickness of the tool R and the cheek plate Q so that the sides of the recess will. also closely engage the sides of the cheek plate Q and thus serve to prevent lateral movement of the guide block V with respect to the extension 0. At the inner end of the recess W is formed a shoulder Y similar to the shoulder S on the extension 0 and adapted to be in line therewith when the guide block V is secured in position on the extension In this way the head U of the breaching tool B may impact equally against bothshoul.- ders. A space Z formed by the shoulders S v 9 breaching tool R which extends into the and Y provides a path for the head U of the breaching "tool so that it may extend freely into the path of the anvil block D to receive the blows transmitted by said anvil. block from the piston C.

Convenient means are provided for quick-. ly securing the guide block V to the exten-' sion 0. To this end the extension 0 is pro vided with slots 6 at its sides to receive eyebolts 0 which in this instance are pivoted on, c

0, one end of the gul mg surface, remova pins d arranged through the extension Suitable slots 6 are likewise formed in the guide block V to receive the eye-bolts 0. Nuts 7 are in this instance screwed on the endsof the eye-bolts o for the purpose of clamping the guide block V firmly in posi-' tion.

The cutting face 9 of the breaching tool iRis preferably concave and is of suflicient length to extend well on opposite sides of a wall It formed. by the drill holes in the rock 70. The cutting face 9 of the broaching tool R is preferably of only slightly greater, thickness than the narrowest portion of the wall 71 so that only a minimum ambunt of material will have to be'rcmoved' between the holes j,

The advantages of this invention reside chiefly in the fact that that end of the front head may be of equal cross sectional area'as that portion of the tool exterior of the front head. In this way a high degree of rigidity may be obtained in the breaching tool and the tendency of the breaching tool to creep or depart from the desired line is eliminated.

I claim:

1. In a broaching. attachment for fluid actuated rock drills of the'hammer type having a cylinder and a reciprocatory hammer piston in the cylinder, the combination of a front head adapted to be secured. to the cyhnder and having an extension, a cheek plate on the extension forming a plane guiding surface, and means engaging the mer piston in the 'tion of a front head adapted to be secured ing a plane cheek plate to cooperate with said plane surface of the extension for guiding a breaching tool.

2. In a broaching attachment for fluid actuated rock drillsof the hammer type having a cylinder and ai reciprocato-ry hammer piston in the cylinder, the combination. of a front head adapted to be secured to the cylinder and having an extension formed with a plane guidin surface, a shoulderbait e means cooperating with the guiding surface of said extension to form a guide broaching tool, and a shoulder on the said means to lie in the same transverse plane as for a tain-ing such broaching tool in the attachment. r

3. In a breaching attachment for fluid actuated rock drills of the hammer type having a cylinder and a reciprocatory hamcylinder,- the combinato the cylinder and having an extension provided with a plane surface, a recessed guide block removably securedto the extension and cooperating with said plane surface of the extension for guidinga broaching tool, and means for clamping said guide block to the extension.

4. In a breaching attachment for fluid actuated rock drills of the hammer type having acylinder and a reciprocatory hammer piston in the cylinder, the combination of a front head adapted to be secured to the cylinder, an extension on the front head, havcheek plate forming one side of a guideway, a removable guide block having a recess to receive and guide a broaching tool. said recess cooperating with the cheek plate for preventing lateral movement of the guide block, and means for clamping the guide block in position.

In testimony whereof I have signed this H specification.

' CHARLES C. HANSEN.

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