US1871728A - Slip rotation apparatus - Google Patents

Description

G. M. NELL Aug. 16, 1932.

INVENTOR. fiz/smve M/VW/ Filed April 6. 1929 SLIP ROTATION APPARATUS A TTORNE Y.

Patented Aug. 16, 1932 earns eus'rAvn'iu. ELL; or nn'rnorr, MICHIGAN, Assrenon r cnfceeo rivnniuarrc TOOL COMPANY, on NEW YORK, 1\T.Y., A oonronerron or nnwannsnr SLIP ROTATION I APPARATUS Application filed April 6,

This invention relates to rock drilling machines and tools, with particular reference to the mechanism by which the drill steel is rotated or stepped around during the drill- :3 ing operation.

lVith conventional rock drills of the self rotating type using rifle bar mechanism, the sticking of the drill steel tends to cause the entire machine to rotate. If the tool is hand Z supported the operator can resist such movement and shut ofl the air. But in the case of the self rotated stoper the guiding handle is sometimes whipped out of the operators hand and as the machine rotates it winds up the hose and may injure the operator before he can get the machine under control. The stuck steel must then be loosened and in forcibly rotating or rocking the machine or in using a bar in the handle or other opening in the machine to secure a leverage, the rotation mechanism is often subjected to a strain beyond its strength with the result that the rifle bar breaks or the threads holding the rifle nut in place arestripped.

One object of the invention is to prevent damage to drills and injury to operators when drill steels become stuck. Another object is to provide for release or slipping ofthe rotation mechanism when subjected to excessive strain. Another object is to devise simple and inexpensivemechanism for securing the above results, which mechanism is readily adaptable to old as well as new machines. Other objects will be apparent from the detailed description which follows.

The invention involves means for causing a slip in the rotation mechanism, as between the rifle bar nut and the piston, so as to minimize, or entirely to prevent, rotation of the machine, as a Whole when the drill steel is under abnormal torsional load or becomes stuck, but which will providefor rotation of the drill steel under normal'conditions.

. By preference the slip grip or friction in 45 the rotation mechanism is made proportional to the torsional strength of the parts most likely to break, so that slip will occur before these parts are overloaded or unduly strained. s In order to illustrate the invention one 1929.") Serial no. 353,206.

concrete embodiment'thereof is shown in the accompanying drawing, in which:

'Fig. 1 is a fragmentary sectional view of so much of a rock drill as is necessary for the understanding of the invention;

Fig. 2 is a transverse sectional view throughthe piston shown in Fig. 1 substantially on the line 22 of Fig. l and Fig. 3 is a right end elevational view of the piston.

The embodiment of the; invention chosen for, the purpose of illustration, discloses a portion of a fluid pressure, self-rotating rock drillhaving a cylinder A in which reciprocates an impact member or piston 4: arranged todeliver blows as well as to impart rotation to a, drill steel (not shown). The reciprocatory movement of piston 4 is utilized to eflect rotation of the samethrough mechanism of the rifle bar type which includes a rifle bar 5 suitably supported in the rear end or back head (not shown) of the drilling machine and extends axially of the piston chamber to cooperate with a rifle nut 6 supported in a, recess 4a in the rear end of the piston, which recess has a reduced eX- tension 4?) to receive bar 5. The rotativeimpulse imparted to pistonl istransmitted by ribs or flutes 40 on the latter in sliding engagement with similar flutes Z) on achuck B into which the drill steel. (not shown) extends. I I

In order to prevent breakage of the parts of the rotation mechanism, or injury to the operator due to the rotation of the entire machine in the event ofa stuck steel, a slip connection is provided somewhere in the rotation train. By preference this slip connection takes the form of a flexible and automatically detachable coupling which is provided on piston 1-. To this end nut 6 has a smooth annular exterior which is journalled in the smooth annular bore of a retainer 7 which takes the form of an externally threaded sleeve for cooperative threaded engagement with the internal threads of recess 4a of piston 4. On its inner end, retainer 7 has a recess 7 a of greater diameter thanits bore to receive a radial flange Go on nut 6, which flange is clamped against the'bottom of recess lawhen 2) of nut 6 While the other end 86 is engaged in a slot 7 Z) in retainer? The rifle nut, retainer, spring assembly (6, 7, 8) is inserted as a unit in recess 4a of piston 4, a wrench being applied to flats 70 (Fig. 3) on the head of retainer 7. The screw threads are in the proper directionto causeretainer 7 to screw into the piston under the impulse or reaction of the rotation mechanism and to take up any clearance between the flanged head 6a of rifle nut 6 andthe bottom of recess a so as to prevent relative longitudinal movement of nut '6. The intensity of this clamping action is limited by the amount of rotational impulse transmitted bythe flexible coupling effected between nut-S and retainer 7 by "spring '8, and it is obvious'that asthe friction between the bottom of recess 4a and flange 6a of the nut increases, there will be a decrease in the screwing up impulse transmitted to retainer 7. Hook end 8a of spring 8 and the cooperating recess 66' in rifle nut 6 are so formed and of such extent as to transmit through coupling spring 8 sulficient impulse for normal rotation requirements but hook end 8a will release or slip out of recess 66 when the rotative impulse exceeds a predetermined amount or becomes excessive through the sticking of the drill steel. 7

I am aware that protection of the rotative mechanism may be secured otherwise than by providing the flexible connection between the rifle nut and the piston, and that other forms of slip and friction'alengaging arrangements may be used without departing from the spirit of this invention. I therefore do not desire to limit the invention to the specific form shown but intend to cover all modifications, adaptations, and equivalent combinations within the scope of the appended claims.

I claim as my invention:

1. In a percussive drill, in combination, a reciprocating percussive member, means responsive to the movement ofsaid member for imparting rot'ative movement to the same,

'" and means on said member responsive to overload for effecting slip between said first named means and said member.

QJIn a percussive drillhaving a reciprocating impact member, rifle bar mechanism for imparting rotation to said memberineluding a rifle nut carried by the latter, and means permitting slip between said nut and said member "when said mechanism is overloaded.

'3. In a percussive drill having a reciprocluding a rifle nut rotatably mounted upon said member, and means providing a yielding connection between said nut and said memberarranged :to disengage when said mechanism becomes overloaded.

5. A piston for a percussive drill having a recess at one end, a rifle nut, means securing said nut in said recess for rotative movement, and means establishing a yielding connection between saidnut and said piston.

6. A piston for a. percussive drill having a recess at one end, a rifle nut, a retainer securing said nut in said recess, and means establishing a said nut and said piston; I

--i piston for -a percussive drill having a recess at one end, a rifle nut, a retainer securing said nut in said recess and providing a bearing therefor, and a slip connection between said nut and said retainer.

-8. A piston for a percussive drill having a recess at one end, a rifle nut having a'flange at one end, a retainer sleeve for securing said nut in said recess with said flange against the bottom thereof, and a slip connection betweensaidnut and said sleeve.

9. A piston for a percussive drill having a recess atone end, a'rifle nut, a retainer securing said nut said recess and providing a bearing therefor,- and -'a spring establishing. a "slip connection between said nut and said retainer) r l0. A piston-for a percussive drill having recess at one end, a rifle nut having a. flange 'a-t'one end, a retainer sleeve 'forse'curing said nut in said recess'with said flange against the bottom thereof, and-a spring encircling said flange and arranged to provide a slip eon nection between said nut and said sleeve. 7

11. A piston for a percussive drill having a recess atone end, a rifle nut having-a flange at one end, a retainer sleeve for securing said nut in'sai'd recess with said flange against the bottom thereof, and a spring encircling "said flange and having reversely directed ends engaging said nut and said sleeve respectively to provide a slip connection between said nut and said sleeve. Y

12; Arifle nut and retainer for insertion as a unitinto a recess in the piston of a fluid pressure tool,- said nut and retainer being in telescoping engagement and relatively rota-t able, and a flexible coupling therebetween arranged to disengage when a predetermined torque upon either is exerted.

13. Arotative unit for'threaded insertion yielding connection between into a recess in the piston of a fluid pressure tool comprising an externally threaded sleeve having a smooth central bore, a rifle member rotatably received Within said bore and k having a radial flange engaging one end of said sleeve, and a flexible coupling between said sleeve and said member arranged to disengage when subjected to a predetermined torque. 3

r 14. A rotative unit for threaded insertion into a recess in the piston of a fluid pressure tool comprising an externally threaded sleeve havinga recess at one end and a reduced axial bore therethrough, a rifle member having a portion journalled in said bore and a radial flange seated in said sleeve recess, and a spring encircling said flange 'Within said sleeve recess and releasably engaging said sleeve and member to provide a flexible con- V nection therebetween.

15. A retainer for securing a rifle nut in the recessed end of a piston comprising an externally threaded sleeve having a smooth axial bore therethrough and a recess at one end of slightly greater diameter than said bore to receive a radial flange on the rifle nut.

Signed by me at Detroit, in'the county of Wayne and State of Michigan, this 2nd day 33 ofApril, 1929.

GUSTAVE M. NELL.

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