US2830792A - Collar for drill steels - Google Patents

Description

APril 1958 c. E. SEARS 2,830,792

COLLAR FOR DRILL STEELS Filed Oct. 13, 1954 'a g. V 4

L BY/III/II/l "(I/Ill Ill/l Il/JL/ INVENTOR FIG-4 CLARENCE E. SEARS Fla-2 BY ms ATTORNEY United States Patents COLLAR FOR DRILL STEELS Clarence E. Sears, Sherbrooke, Quebec, Canada, assignor to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application October 13, 1954, Serial No. 462,077

7 Claims. (Cl. 255-37) This invention relates to drill steels, and more particularly to a collar that is readily attachable to the shank portion of a drill steel.

Drill steels of the type to which the present invention pertains are used in percussive rock drills equipped with retainers for cooperation with the collar to maintain within workable limits the shank length recommended by the manufacturers as well as to retain the shank end of the drill steel in the rock drill and to interlockingly engage the collar for withdrawing the drill steel from a drill hole. i

Heretofore, it has been customary to form the collar by upsetting a portion of the steel at a point chosen as the juncture of the body portion of the steel and its shank. This mode of forming the collar requires repeated heating and forging operations, and in the case of hollow drill steels it becomes necessary to pin-out the material that flows into the passage in the drill steel after each forging operation.

These operations, as will be readily appreciated, require a considerable degree of skill and numerous and costly mechanisms for carrying them out, and in many instances defects develop in the area of the collar that cause failure of the drill steel when subjected to the heavy stresses of drilling. i

It is accordingly an object of this invention to obviate the need of disturbing the initial form of a drill steel requiring a collar.

Another object is, to enable a drill steel to be expeditiously equipped with a collar without the need of special skill or costly machinery.

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

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

Figure l is a side elevation of the front end portion of a rock drill and a drill steel having its shank end extending into the rock drill, the drill steel being equipped with a collar constructed in accordance with the practice of the invention,

Fig. 2 is an elevation, partly in section, of a drill steel and a collar afiixed thereto,

Fig. 3 is a transverse view through Fig. 2 on the line 3-3,

Fig. 4 is a fragmentary portion of the casing parts of the collar showing them in position for attachment to each other,

5 is a view similar to Fig.4 showing the casing parts permanently secured together, i

Fig. 6 is an elevation, partly in section, of the shank portion of a drill steel, a collar and a pilot seated upon the end of the drill steel for guiding the collar onto the drill steel, and

Fig. 7 is a transverse view taken through Fig. 6 on the line 7-7.

Referring to the drawings and at first more particular- Patented Apr. 15, 1958 1y to Figure 1, 20 designates the front end portion of a rock drill, 21 a drill steel actuated by the hammer piston 22 of the rock drill and 23 a retainer for preventing ejection of the drill steel from the rock drill. The casing of the rock drill 20 is provided, as is customary, with trunnions 24 to support the retainer 23, and the yoke 25 of the retainer partly encircles the drill steel 21 at a point forwardly of the collar 26.

The collar 26 comprises an elongated member 27 in the form of a sleeve that may be shaped internally to conform to the contour of the drill steel 21 or may, if desired, be of cylindrical shape to receive drill steels of corresponding or polygonal shapes. The member is constructed of elastic material, as for example rubber or neoprene which is readily deformable and may, therefore, be conveniently constricted and pressed into firm gripping engagement with the drill steel.

In a preferred form, the member 27 is exteriorly of cylindrical shape and its bore 23 comprises a similarly shaped intermediate portion 29 of smaller diameter than the drill steel. The front and rear end portions 30 and 31 of the bore 28 flare outwardly toward the ends of the member to accommodate the material that is displaced at the intermediate portion of the member during the operation of attaching the collar to the drill steel.

The member 27 is encased'in a sleeve 32 to which its peripheral surface 33 is bonded and is of somewhat less length than the sleeve. The front end 34 of the member 27 initially lies flush with the corresponding end of the sleeve and some of the material of the member 27 will then protrude from the sleeve when attached to the drill steel 21, as indicated at 35 in Figs. 1 and 2 of the drawings, to cushion the blow of the collar against the yoke 25, Owing to the difference in lengths between the sleeve 32 and the member 27 a space 36 will remain in the rearward end of the sleeve into which the material of the member displaced by the drill steel may flow. The space 36 is, however, of sufficient length to preclude the complete filling of the space 36 in order to avoid contact of the rearward end of the member 27 with a cap 37 on the adjacent end of the sleeve and thereby enable the member to yield slightly when the collar assembly is thrust against the rock drill or the retainer. The cap 37 serves as a buffer for the sleeve to protect it against damage upon impact of the colar against the front end of the rock drill, as when the drill steel rebounds from the working surface.

The cap 37 has an aperture 38 therethrough to slidably receive the drill steel, and in the forward surface of the cap is an annular groove 39 the sides 40 of which diverge from the open end of the groove. The bottom of the groove consists of a pair of inclined surfaces 41 that define an annular edge 42 at the line of convergence to engage the end of the sleeve and swage the adjacent portion thereof into firm engagement with the side surfaces 46 of the groove. Such flaring of the sleeve within the groove may be readily effected by the force of the impact of the sleeve against the edge 42 when the collar assembly I is thrust against the rock drill by the drill steel.

Whenever it is intended to attach a collar to a drill steel, the assembly comprising the member 27, the sleeve 32 and with the cap 37 loosely seated upon the sleeve are disposed upon a pilot 43 of cone shape seated upon the rearward end of the drill steel. Pressure of a suitable value is then applied to the cap 37 and the assembly is forced thereby along the pilot which will gradually displace the material of the member 27. When the member 27 passes over the large end of the pilot it will be interiorly of the correct size and shape to receive the drill steel and the collar may then be slid along the length thereof to the desired location.

In actual practice, it has been found that the collar will remain in the correct assembled position throughout the life of the drill steel, irrespective of any jars or shocks it may re'eeive in service and 'that, although pressed inrm'ovably" against the steel by the sleeve 32, the member 27 retains sulfici'en't resiliency to-adequately cushion the blows of the sleeve against the rock drilland the retainer 23 and thereby minimize damage to the collar assembly.

T claim:

l. The combination with a drill steel, of a collar including an elastic member to encircle the drill steel, a sleeve to encircle and constrict the elastic memberinto firm grippinge'ngagement with the drill steel, and a cap on one end of the sleeve having a sliding fit on the drill steel and having its inner side surface spaced from the adjacent end of said member.

2'. The combination with a' drill steel, of a. collar including an elastic member to encirclethe drill steel, a sleeve to encircle and constrict the elastic member into firm gripping engagement with the drill steel and being bo'nrledto the peripheral surface of the elastic member and being positioned on said member such that one end portion of the sleeve extends beyond the associated end of said member, and a cap on said end of the sleeve and having a slidingfi t on the drill steel.

3. The combination with a drill steel, of a collar including an elastic member to encircle the drill steel and having a smaller internal diameter when unstressed than the diameter of the drill steel, a sleeve to encircle and constrict the elastic member into firm gripping engagement with the drill steel and being bonded to the peripheral surface of the elastic member, the unstressed outside dimensions of said member correponding substantially to the internal dimensions of said sleeve, and a cap on one end of the sleeve having a sliding fit on the drill steel.

4. The combination with a drill steel, of a collar including an elastic member to encircle the drill steel, a sleeve of greater length than the unstressed length of the elastic member to encircle and constrict said member into firm gripping engagement with the drill steel and having one end initially flush with an end of the elastic member, said sleeve being bonded to the elastic member, and a separate cap mounted on the other end of the sleeve having a sliding fit on the drill steel.

5". The'combination with a drill steel, of an elastic member to encircle the drill steel and having a smaller internal diameter than the diameter of the drill steel, a sleeve to encircle and constrict the elastic member into firm gripping engagement with the drill steel and being bonded to the elastic member, a cap having a sliding fit on the drill steel and having an annular groove of dovetail cross-sectionin one side thereof, and a flared end on the sleeve lying Within the groove to secure the cap to the sleeve.

6. The combination with a drill steel, of an elastic member to encircle a drill steel, a sleeve to encircle and constrict the elastic member into firm gripping engagement with the drill steel, a capfor the sleeve encircling the drill steel and having an annular groove in one side to receive an end portion of the sleeve, and means at the bottom of the groove to swage such end portion of the sleeve into firm engagement with the sides of the groove accordingly as the end portion of the sleeve is driven into the groove.

7. The combination with a drill steel, of an elastic member to encircle a drill steel, a sleeve to encircle and constrict the elastic member into firm gripping engagement with the drill steel, a cap for the sleeve encircling the drill steel and having an annular groove of dove-tail cross-section in one side to receive an end portion of the sleeve, and a Wedge-shaped bottom in the groove to swage such end portion into firm engagement with the sides of the groove accordingly as said end portion is driven into the groove.

References Cited in the file of this patent UNITED STATES PATENTS Great'Britain Mar. 31, 1943

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