US2236700A - Feeding device - Google Patents

Description

A ril 1, 1941. F, M L R 2,236,700

FEEbmc- DEVICE Filed Nov. 23, 1940 INVENTOR EedMcfi/afep.

H I 5 ATTORNEY.

Patented Apr. 1, 1941 2,236,700 I FEEDING DEVICE Fred M. Slater, Phillipsburg, N. J., assignor to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application November 23, 1940, Serial No. 366,833

7 Claims.

This invention relates to rock drilling mechanism, and more particularly to a pressure fluid actuated feeding device for advancing a rock drill toward and retracting it from the Work.

One object of the invention is to apply a feeding force to the rock drill best suited for efficient drilling in the particular type of rock being drilled.

Another object is to avoid undue wear on the rotative parts of the rock drill.

Another object is to automatically cut-off the power to the feeding device whenever the pressure against the rotative parts of the rock drill becomes excessive, and

Still another object is to cause the pressure fluid actuated feeding device to automatically resume operation after the pressure on the rotative parts of the rock drill has been relieved.

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

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

Figure 1 is a longitudinal side view, partly broken away, of a rock drill, its guide member and a feeding device for actuating, the rock drill along the guide member,

Figure 2 is a plan view, partly in section, taken through Figure 1 on the line 2-2, and

Figure 3 is a transverse view taken through Figure 2 on the line 33.

Referring more particularly to the drawing and at first to Figure 1, the drilling mechanism, designated in its entirety by 20, comprises a rock drill 2| mounted upon a guide member in the form of a shell 22, and at the rear end of the shell is a feeding motor 23 for actuating the rock drill, 2| longitudinally of the shell through the instrumentality of a feed screw 24.

The shell 22 may be of a well known type having a cone 25 for cooperation with a suitable clamping device (not shown) whereby thedrilling mechanism may be secured to a stationary mounting. In the opposed inner surfaces of the shell are longitudinally extending grooves 26 to receive, slidably, ribs 21 extending along the opposite sides; of the rock drill 2|.

The rock drill 2| likewise may be of a conventional type comprising a cylinder 28 and front and back heads 29 and 39, respectively, which may be secured to the cylinder in any suitable manner. The cylinder and the heads 29 and 30 constitute the casing parts of the rock drill, and within the front head 29 is a chuck 3| to receive the shank end 32 of a drill steel 33 having lugs 34 to slidably interlock with the chuck.

The chuck 3| is of the rotatable type to which rotary movement may be transmitted by suitable mechanism (not shown) incorporated in the rock drill in a well known manner, and in the chuck 3| is a chuck bushing 35, the front end of which acts as an abutment for the lugs 34 to limitthe distance which the Working implement may extend into the rock drill.

At the rearward end of the cylinder 28 is a lug 36 extending into the shell 22 and containing a feed nut, 31 that is in threaded engagement with the feed screw 24 and locked securely in position by a nut 38 seating against the end of the lug 36. The motor 23 which is attached to the rear end of the shell 22 by standards 39 is of the fluid actuated rotary vane type. It comprises a cylinder 40 having lugs 4| to receive the standards 39 and is bored to provide a chamber 42 for the accommodation of a piston or rotor 43. The rotor 43 is disposed eccentrically within the chamber 42 and has a plurality of radial slots 44 containing vanes 45 against which pressure fluid acts for rotating the rotor.

The motor 23 is of the reversible type and the direction of rotation thereof is controlled by a valve 46 rotatable in a chamber 41 in a plate 48 disposed upon the standards 39 and forming a closure for the rearward end of the chamber 42. The valve 46 has a bore 49 which is in constant communication with a source of pressure fluid supply through a conduit 59, attached to the plate 43, and in the wall of the valve is a port 5| that opens into the bore 49 and is adapted to register with passages 52 and 53 leading from the valve chamber 41 to opposite sides of the point of minimum clearance between the wall of the chamber 42 and the periphery of the rotor 43.

The chamber 42 is also provided with free exhaustports I8 and I9 arranged on the opposite sides of the plane of maximum clearance between the wall of thechamber 42 and the periphery of the rotor 43. A lever 54 is attached to the valve 46 for rotating it to admit pressure fluid selectively into the passage 52 or the passage 53 for rotating the rotor in one direction or the other.

The rotor 43 is mounted upon a shaft 55 journaled in the plate 48 and a plate 56 at the front end of the chamer 42 and is secured to the rotor by a key 51. The shaft 55 extends forwardly of the plate 56 and carries a sun pinion 58 that meshes with planet pinions 59 meshing with an internal gear, or, as illustrated, with teeth 60 'on the inner surface of a casing 6| seating against the plate 58. The casing GI and the plate 56 are also arranged upon the standards 39 and, with the cylinder 4| and the plate 48, constitute the casing of the motor assembly and are clamped securely together by bolts 62 extending lengthwise of the motor.

The planet pinions are mounted upon spindles 83 seated in a carrier 84 rotatable in the casing ill. The carrier 64 has a skirt 85 at its front end journaled in a bushing 66 in the casing BI, and on the front end. of the skirt is a reduced extension 61 that projects through the front end of the casing GI and abuts a collar 68 on the feed screw 24.

In the structure shown the feed screw is provided with a tapered shank 69 that extends into a tapered bore 18 in the skirt 65 and is drawn into firm frictional engagement with the carrier by a nut H threaded on the shank 69 and seating against a shoulder 12 in the carrier.

In order to avoid the forcing of the chuck parts of the rock drill heavily against the lugs 34 of the working implement by the motor 23 when drilling rock of such hardness that the Working implement may penetrate it only slowly, the motor 23 is capable of sliding rearwardly along the standards 39 to relieve the pressure upon the chuck parts. To the end that such retrograde movement of the motor may be yieldingly resisted the rearward end of the plate 41 is seated against a spring 13 of which the opposite end seats against a crosshead I4 disposed upon the rearward ends T of the standards 39. The ends 15 or the standards are threaded to receive nuts Hi that retain the cross head 14 on the standards. The nuts 18 may also serve to move the crosshead along the standards 39 for regulating the force of the spring 13 which is placed initially under compression to hold the motor 23 in a forwardly position and normally seated against collars ll on intermediate portions of the standards 39.

Thus, as will be readily appreciated, the motor 23 may normally apply its full torque to the rock drill for feeding it towards the work in accordance with the progress of the working implement 33. The motor will be held firmly against the collar ll of the standards by the spring 13 but when the working implement penetrates the work slowly, as when drilling hard rock, the rotative force of the motor will cause the motor to be moved gradually rearwardly along the standards and against the pressure of the spring 13, it being understood of course that the feed screw 24 is also capable of endwise movement relatively to the shell 22.

In order to avoid a condition in which the spring 13 may become compressed to a degree approaching rigidity and again create a condition under which the full torque of the motor 23 is applied to the rock drill, it is contemplated to cut-off the power supply to the motor automatically whenever the spring 13 has been compressed to a degree in which its force alone is sufficient to advance the rock drill 2| at a rate suitable for maintaining the percussive element of the rock drill in the correct striking relationship with of the valve, and in the intermediate portion of the valve is an annular groove 82 to effect communication between the branches 83 and 84 of the passage 52. In the normal position of the valve 19 the branches 83 and 84 of the passage 52 are in communication with each other through the annular groove 82 to admit pressure fluid to the chamber 42 for imparting feeding movement to the rotor 43.

If desired, the valve 19 may be actuated manually to cover the branch 83 of the passage 52 for cutting oif the supply of pressure fluid to the motor, as by applying pressure to the stem 80. Preferably, however, an abutment is provided for the stem 88, as for example by threading a screw 85 into the crosshead I4 and locking said screw fixedly to the crosshead by a lock nut 86. Being threaded to the crosshead, the screw 85 may be readily adjusted to any desired position to cause the valve to assume a position in which it overlies the branch passage 83, either early or late in the rearward movement of the motor 23 along the standards 39.

The operation of the device, briefly summarized, is as follows: Normally, when drilling rock of a nature that oifers no more than the usual resistance to the penetration of the working implement thereinto the full force of the motor is applied to the rock drill for advancing it toward the work. The motor is then held in a forwardly position against the collar 11 by the spring 13 and the valve 19 will occupy a position in which the branches of the passage 52 are in full communication with each other through the groove 82 to supply pressure fluid to the chamber 42 for driving the rotor.

In the event, however, that hard rock is encountered by the working implement and in which case penetration necessarily takes place slowly the motor 23 will be forced gradually rearwardly along the standards 39 and will further compress the spring 13. If the abnormality in the rock is of only slight extent it may be reduced by the working implement before the motor 23 has reached a position in which the position of the valve 19 will be disturbed. But if resistance to the forward movement of the rock drill continues the motor will move rearwardly along the standards and when the stem 89 abuts the screw 85 further movement of the motor in a rearwardly direction will cause the branch 83 to move out of communication with the groove 82 and in this way the supply of pressure fluid to the motor will be cut-off.

Thereafter, only the spring 13 will act to drive the motor and the rock drill forwardly to maintain the rock drill in the correct relationship with the drill steel. After the rock drill and the motor have advanced toward the work a sufficient distance to again move the stem out of contact with the screw the passage 52 will be uncovered by the valve 19 and the motor will again resume operation to exert feeding pressure on the rock drill.

The described retrograde movement of the motor on the standards and the cutting off of pressure fluid to the motor by the valve 19 may occur repeatedly throughout the drilling operation but it will be readily understood that the rotative parts of the rock drill and of the motor will be subjected at all times only to such pres sure as may be exerted by the spring 13. Inasmuch as this pressure may be conveniently controlled the rotative parts will always be protected against undue wear, such as is caused in devices in which the feeding pressure is of a value that tends to tilt the rotative parts into binding engagement with the elements serving as bearings therefor.

It will, moreover, be apparent that the device above described is particularly suited for pressures of difierent values. For example, if a pressure of comparatively low value is used for driving the motor no excessive feeding force may, in any event, be applied to the rock drill. 0n the other hand, if a considerably greater pressure value is employed for driving the motor the force against the rotative parts of the rock drill and the motor will be adequately relieved. In either case the feeding pressure will not exceed that exerted by the spring 13.

I claim:

1. In a feeding device, the combination of a support and a rock drill slidable thereon, a pressure fluid actuated feeding motor for the rock drill slidable on the support, and cushioning means to yieldingly resist sliding movement of the motor relatively to the support.

2. In a feeding device, the combination of a support and a rock drill slidable thereon, a pressure fluid actuated feeding motor for the rock drill slidable on the support, and a spring interposed between the motor and the support to yieldingly resist sliding movement of the motor with respect to the support.

3. In a feeding device, the combination of a support and a rock drill slidable thereon, a pressure fluid actuated feeding motor for the rock drill slidable on the support, a spring to yieldingly resist sliding movement of the motor with respect to the support, and adjustable means for varying the resistance of the spring.

4. In a feeding device, the combination of a support and a rockdrilltslidable thereon, a pressure fluid actuated feeding motor for the rock drill slidable on the support, cushioning means to yieldingly resist sliding movement of the motor with respect to the support, a valve for controlling the admission of pressure fluid to the motor, and means for effecting the automatic shifting of the valve from one controlling position to another during movement of the motor relatively to the support.

5. In a feeding device, the combination of a support and a rock drill slidable thereon, a pressure fluid actuated feeding motor slidable on the support, cushioning means to yieldingly resist sliding movement of the motor with respect to the support, a valve for controlling the admission of pressure fluid to the motor, and an adjustable abutment for effecting the automatic shifting of the valve from one controlling position to another during movement of the motor relatively to the support.

6. In a feeding device, the combination of a support and a rock drill slidable thereon, a pressure fluid actuated motor for the rock drill slidable on the support, a spring to yieldingly resist sliding movement of the motor relatively to the support, a seat on the support for the spring and being adjustable to vary the force of the spring, a valve to control the flow of pressure fluid to the motor and being normally in a position to admit pressure fluid to the motor, and an adjustable abutment in the seat to effect the shifting of the valve to a position for cutting off the admission of pressure fluid to the motor during the movement of the motor in one direction along the support.

7. In a feeding device, the combination of a support and a rock drill slidable thereon, a pressure fluid actuated motor for the rock drill slidable on the support, means for yieldingly resisting movement of the motor relatively to the support, and means for automatically cutting off the supply of pressure fluid to the motor during movement of the motor with respect to the support.

FRED M. SLATER.

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