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 l L 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 a cylinder 2! and front and back 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-pressed side bolts 24.

Within the cylinder 2| is a piston chamber 25 having a free exhaust port 26 and containing a reciprocatory hammer piston 21 that controls the exhaust port 25, and in the rearward end of the cylinder 2! is a valve chamber 28 that communicates with the rear and front ends of the piston chamber through ports 29 and 30, respectively, and contains a distributing valve 3|, of the oscillatory plate type, for controlling the flow of pressure fluid from the valve chamber 28 to the ends of the piston chamber. The supply of pressure fluid for the valve chamber 28 is conveyed thereto by a passage 32 in the back head 2.3, and communication between the passage 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 the piston chamber 25 is closed by a front cylinder washer 34, and a stem 35 on the piston extends slidably therethrough to strike against a drill steel 36 guided by the front head 22 in a well known manner.

The back 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 extending arms 31 having apertures 38, preferably of rectangular shape, to accommodate blocks 39 that are slidable therein endwise of the arms 31. At the outer ends of the blocks, and on the opposite sides thereof, are flanges 49 to bear against the outer sides of the arms 31, and the inner ends of the blocks seat against the ends of a sleeve 4| that holds the blocks 39 in suitably spaced relation with each other to determine the correct degree of clearance between the flanges 40 and the arms The blocks 39 and the sleeve 4| are apertured to accommodate a bolt 42 that supports, on its end portions, rubber grip members 43 containing reinforcing sleeves 44 that seat at their inner ends against the blocks 39 and at their outer ends against washers 45, one of which is interposed between the head 46 of the bolt and the grip portion and the other between the nut t! on the bolt 42 and the adjacent grip portion 43. Owing to this arrangement, the pressure of the bolt head 46 and the nut 4'! against the outer ends of the sleeves M will press the blocks 39 firmly. "against the ends of the sleeve 4! and the grip 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 the apertures 38 lie exteriorly of the plane of the cylinder 2| and on the same Side of the cylinder is an enlargement 48 which is recessed to provide a cushioning chamber 49 that is sealed at its rearward, open end by a plug 50 having an aperture 5| to receive, slidably, a transmission member shown as being in the form of a rod 52 that extends slidably through the back head 23 and at its rearward end into a recess 53 in the sleeve ll to abut the bolt $2.,

The opposite end of the rod 52 lies within the cushioning 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 the cushioning chamber 49 through a passage 56 leading thereto'from the forward end of the piston chamber 25 and a spring-pressed check valve 51 in the passage 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 the piston 21 rearwardly will flow through the passage 56 3 into the cushioning chamber 49 and, acting against the pressure surface, will press the rod 52 against the bolt 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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