US2531800A - Cushioning device for rock drill handles - Google Patents

Description

Nov. 28, 1950 J. H. ANDERSON 2,531,800

CUSHIONING DEVICE FOR ROCK DRILL HANDLES Filed Nov. 22, 1947 as 31 44 46 39 3 Y W 5 4 3 i n. M

2| 42 I lL 24 24 53 |l 38 4s INVENTOR JAMES H. ANDERSON.

HIS ATTORNEY.

Patented Nov. 28, 1 950 CUSHIONING DEVICE FOR. noon DRILL HANDLES James H. Anderson, Easton, Pa., assignor to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application November 22, 1947, Serial No. 787,595

This invention relates to rock drills, and more particularly to a cushioning device for rock drills of the manually supported type having handles whereby the rock drill may be held to the work.

One object of the invention is to minimize the transmission of shock and vibration from the rock drill to the handle.

A more specific object is to utilize the air compressed by the rock drill piston in an end of the piston chamber as a medium for cushioning the handle of the rock drill.

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 1 is a side elevation, partly broken away, of a rock drill having the invention applied thereto,

Figure 2 is an elevation taken through Figure 1 on the line 2-2,

Figure 3 is a transverse view taken through Figure 1 on the line 3-3, and

Figure 4 is a perspective view of a detail.

Referring more particularly to the drawings, the invention is shown embodied in a rock drill comprising acylinder 2! and front andback heads 22 and 23, respectively. These parts constitute the casing of the rock drill and are clamped together in assembled relationship by the usual spring-pressedside bolts 24.

Within thecylinder 2| is apiston chamber 25 having afree exhaust port 26 and containing areciprocatory hammer piston 21 that controls theexhaust port 25, and in the rearward end of thecylinder 2! is avalve chamber 28 that communicates with the rear and front ends of the piston chamber throughports 29 and 30, respectively, and contains a distributing valve 3|, of the oscillatory plate type, for controlling the flow of pressure fluid from thevalve chamber 28 to the ends of the piston chamber. The supply of pressure fluid for thevalve chamber 28 is conveyed thereto by apassage 32 in the back head 2.3, and communication between thepassage 32 and the source of pressure fluid supply (not shown) is controlled by a throttle valve 33 rotatable in the back head.

The front end of thepiston chamber 25 is closed by afront cylinder washer 34, and astem 35 on the piston extends slidably therethrough to strike against adrill steel 36 guided by thefront head 22 in a well known manner.

Theback head 23, as is customary, supports the handle structure for the rock drill and, to this 5 Claims. (Cl. 121-36) end, is provided with a pair of rearwardly extendingarms 31 havingapertures 38, preferably of rectangular shape, to accommodateblocks 39 that are slidable therein endwise of thearms 31. At the outer ends of the blocks, and on the opposite sides thereof, areflanges 49 to bear against the outer sides of thearms 31, and the inner ends of the blocks seat against the ends of a sleeve 4| that holds theblocks 39 in suitably spaced relation with each other to determine the correct degree of clearance between theflanges 40 and the arms Theblocks 39 and the sleeve 4| are apertured to accommodate abolt 42 that supports, on its end portions,rubber grip members 43 containing reinforcingsleeves 44 that seat at their inner ends against theblocks 39 and at their outer ends againstwashers 45, one of which is interposed between thehead 46 of the bolt and the grip portion and the other between the nut t! on thebolt 42 and theadjacent grip portion 43. Owing to this arrangement, the pressure of thebolt head 46 and the nut 4'! against the outer ends of the sleeves M will press theblocks 39 firmly. "against the ends of the sleeve 4! and thegrip members 43 will be restrained against endwise movement on the bolt.

In the form of the invention shown, the arms 3'! are so positioned that the longitudinal planes of theapertures 38 lie exteriorly of the plane of thecylinder 2| and on the same Side of the cylinder is anenlargement 48 which is recessed to provide acushioning chamber 49 that is sealed at its rearward, open end by aplug 50 having an aperture 5| to receive, slidably, a transmission member shown as being in the form of arod 52 that extends slidably through theback head 23 and at its rearward end into arecess 53 in the sleeve ll to abut the bolt $2.,

The opposite end of therod 52 lies within thecushioning chamber 49 and carries a head54 having a pressure surface 55 at its free end against which cushioning fluid acts for cushioning the movement of the handle structure longitudinally of the rock drill. The cushioning medium flows into thecushioning chamber 49 through apassage 56 leading thereto'from the forward end of thepiston chamber 25 and a spring-pressedcheck valve 51 in thepassage 56 prevents the return flow of fluid medium from the cushioning chamber to the piston chamber.

In practice, a portion of the pressure fluid initially admitted to the front end of the piston chamber by the valve 3| for driving thepiston 21 rearwardly will flow through thepassage 56 3 into thecushioning chamber 49 and, acting against the pressure surface, will press therod 52 against thebolt 42. Thereafter, each time the piston approaches the end of its working stroke some of the air compressed thereby will flow into the cushioning chamber. The pressure valueflof the air. thus compressed' is; as. is

well known, considerablyhigher than that of the fluid serving to actuate the piston and may,

therefore, be of sufficiently high value when act-.-

ing against a small pressure surface 55. tosubstantially balance the force applied by the opera tor to the handle for pressing the drill steel against the work. This is highlydesirable since it obviates the need of adding materiaily to the weight of the rock drill as would be the case were motive fluid used as the cushioning medium.

I claim:

1. In a cushioning device for rock drills, the combination of a casing: having a piston chambei'; a.-.fiuidactuated recipro'catory piston in thepiston-chamber acting to compress fluid. insaid pistonchamber, guide means on the casing, a; handle for guiding the rockdrill and being slid-v able' in theg'uide Ineansand means subjected to fluid medium compressed'by the piston for cushioning them'ovementof the handle.

2'. In a cushioning device for rockdrills, the.

combination of a casing having a piston chamber, afluid actuated reciprocatory. pi tonin the piston chamber. to compre s in said.

piston chamber, guide means on the casing, av

handle forguiding the rock drill and being slidable inthe guide means, a cushioning chamber in the casing, a transmission member to engage the handle andex-tending into the cushioning ber; a pressure surface on the transmission memher, and a passage in the casing to oonveyfiuid.

ber in the casing, a transmission member to engage the handle and extending into the cushioning chamber, a pressure surface on the transmission member, and a passage in the casing to convey fluid medium compressed by the piston from the front end of the piston chamber to act against the pressure surface for cushioning the handle.

4. In a cushioning devic for rock drills, the combination of a casing havin a piston chamher, a fluid actuated reciprocatory piston in the piston chamber; a handle for guiding the rock drill and being movable endwise thereof, a cushioning; chamber; in the casing, a transmission member subjected to cushionin fluid within the cushioning chamberand engaging the handle for cushioning themovement of the handle, a passage in the casing to convey cushioning fiuid from the piston" chamber into the cushioning chamher, and a check valve tcrcontrol the passage for preventing the return flow of cushioning fluid throughthe passage,

5. In: a cushioning device for rock drills, the,

combinationof a casing having a piston chame ber, a fiuidactuated reciprocatory piston in the piston. chamber, a handle for guiding the rock, drill and being movable endwise thereof, means I on the casing for guiding the handle, an en'- largement; on the side of the casing having a cushioning chamber, a transmission member in the cushioning chamber to engage the handle, means on the casing to guide the transmission member, a passage in the casing to convey cushioning' fluid from an. end of the piston chamber into the-cushioning chamber, and check valve;

for preventing the return flow of cushioning fluid,

through the passage.

JAMES H. ANDERSON.

REFERENtJES CITED The following file of this patent:

UNITED STATES PATENTS references are of record in the-

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