US2378802A - Controlling device - Google Patents

Description

. J u ne 19, 1945. I SLATER" 2,378,802

CONTROLLING DEVICE Filed March 12,- 1945 J7 60 55 59 50 n (9 O 56 7? 43 5 y 4 47 50 v 66 46 r v g 68 J INVENTOR- IvcdM-Slafev.

Hi5 ATTORNEY- Patented June 19, 1945 CONTROLLING DEVICE Fred M. Slater, Phillipsburg, N. J., assignor to Ingersoll-Rand Company, New York, N. Y., a

corporation of New Jersey Application March 12, 1943, Serial No. 478,869

1 Claim.

This invention relates to fluid pressure impulse systems for-operating fluid actuated machines, and more particularly to a controlling device for controlling theoperation of a compressor of such a system.

It is an object of the invention to control the operation of the compressor in accordance with the power requirements of the tool utilizing the discharge output of the compressor.

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

In the drawing accompanying this specification and in which similar referenc munerals refer to similar parts,

Figure 1 is a side elevation of a pneumatically actuated tool and the devices required for supplying the pressure fluid used for operating the tool, y

Figure 2 is an elevation, partly in section, of a controlling device serving to regulate the power output of the power elements in accordance with the requirements of the tool actuated thereby, and

Figure 3 is a view, in section, of a detail.

Referring to the drawing, and at first more particularly to Figure l, 25 is apneumatically actuated tool, as for example a rock drill of the hammer type, and 25 is a compressor, the discharge end of which is connected -to the tool 29 by a conduit 22 so that the compressor discharges directly into the conduit which constitutes the of the compressor. The'engine 3| .is provided with the usual intake manifold 31 and with a carburetor 33 in communication with the ,latter through "a conduit 39 containing a butterfly valve 40 that serves to control the fuel supply from the carburetor to the engine}! in a manner well known.

storage vessel for the pressure fluid required for operating the tool 26.

Communication between the conduit 22 and the tool 2 3 is controlled by manually operable valve means 23 positioned within convenient reach of the operator of the tool. The valve means 23 may, as shown, comprise a casing 24 that is connected to the tool 20 by a fitting 25, and a similar fitting 26 forms the connection between the valve casing 24 and the conduit 22.

Within the casing 24 is a rotary throttle valve internal combustion engine 3| that is mounted upon the base 32 supporting the compressor 2! and has a sheave 33 on its crank shaft 34 for a belt 35 that is trained over the drive sheave 3B -The butterfly valve 4!!" is pivotally connected to a link 4! through which force is transmitted for oscillating the valve 40, and in accordance with the practice of the invention means, acting responsively to the value of the pressure Within the conduit 22 are provided for shifting the link 4land thus the butterfly valve 40. The controlling device serving this function is designated in its entirety by 42. It comprises a casing 43 that is seated upon the base 32 to which it may be secured in any suitable manner. The casing 43 is recessed to provide apressure chamber having a port 45 to which is connected an end of a pipe 46 having its other end connected to the conduit ZZ so that the pressure chamber 44 will be in constant communication with the conduit On the top of the casing 43 is a seating surface 41 that encircles th pressure chamber 44 to support the marginal portion of a flexible diaphragm 43 that is clamped to the seating sur face by a cover 49 and by screw 50 that may extend through the cover and the diaphragm and be threaded into the casing.

In the centralportion of the diaphragm 48 is an aperture 5! to receive a threaded end or portion 52 of a rod 53 that extends loosely through a hole 54 in the cover 45. The end 52 of the rod 53 is secured to the diaphragm by nuts 55 on the rod acting against the opposite sides of the diaphragm through washers 56 interposed between the diaphragm and the nuts. 1

The upper end of the rod 53 is pivotally connected to an end of a rocker arm 51 fulcrumed, intermediate its ends, upon a pivot 58 in an arm 59 on the top of the cover 49. The opposite end of the rocker arm 51? is pivotally connected to an end of a link 60 the opposite end of which is pivotally connected to an arm 6! of a bell crank $52. The other arm 53 of the bell crank is, in turn, pivotally connected to the link 4|, and in the angle of the bell crank is a pivot 84 that may be supported in any convenient manner. Atension spring 85 connected at one end to the arm 53 of the bell crank and at its other end to the conduit 39 exerts a constant pull tending to maintain the throttle valve 40 in its closed position.

Means are provided to prevent a too abrupt movement of the diaphragm and the elements actuated thereby including the throttle valve 40 and the linkage connecting the two. Th controlling device 42 is accordingly provided with a checking device 66 that acts in opposition to the pressure acting against the diaphragm 48.

The checking device is preferably also arranged in the casing 43 in convenient position for connection to the rocker arm 51 at a point intermediate the pivot 58 and the link 60. It comprises a plunger 61 in a cylinder 68 on the casing 43, and interposed between the inner end of the plunger and the bottom of the cylinder 68 is a compression spring 69 that tends constantly to move the plunger 61 outwardly toward the rocker arm 51. A rod is connected to the rocker arm 51 by a pivot H and is threaded, for adjustment, to the plunger 61 and has a lock nut 12 for holding the plunger 61 against unauthorized rotative movement with respect to the rod 10.

An orifice l3 communicates the lower end of the cylinder 68 with the atmosphere to permit anstricted flow of air into and out of the cylinder during the reciprocations of the plunger 61 to exert a checking effect upon the plunger.

During the operation of the tool 20, and therefore the compressor, the throttle valve 21 occupies a position in which the groove 29 establishes communication between the conduit 22 and the tool 20, and the total output of the compressor 2| will then pass directly to the tool for operating it.

Inasmuch as the pressure chamber 44 is also in constant communication with the conduit 22 through the pipe 46 the diaphragm 48 will then be subjected to the same pressure as that existing in the conduit 22.

Such pressure acting against the diaphragm will have the effect of moving the rod 53 upwardly and imparting a counter movement to the link 6|] and thereby tilt the bell crank 62 about its pivot. This movement of the bell crank will, in turn, rotate the throttle valve 40 to open it for admitting an increased supply of fuel to the engine 3|.

The force thus acting against the diaphragm 48 and the consequent tilting movement of the rocker arm 51 will move the plunger 61 downwardly against the resistance of the spring 69. Owing, however, to the dash-pot efiect of the checking device 66 such movement of the rocker arm will take place gradually so that the throttle valve will open at a suitable rate of movement to assure a smooth acceleration of the engine speed.

Upon completion of a run of drilling, as when a hole of desired depth has been drilled, the throttle valve 21 is rotated to another limiting position to cut-off the flow of pressure fluid to the tool 20 and to establish communication between the conduit 22 and the atmospheric exhaust port 30, In this position of the throttle valve the discharge output of the compressor passes to the atmosphere and the pressure chamber 44 will be evacuated. The spring 69 will then act to tilt the rocker arm 51 about its pivot 58 and move the linkage connected thereto in the required direction for closing the throttle valve 40 and thereby diminish the fuel supply to the engine 3| to cause the latter to run at an idling speed until the throttle valve is again positioned to communicate the conduit 22 with the tool 20.

From the foregoing description of the invention it will be readily apparent that it forms a convenient means for controlling the power sup- 7 ply to the engine 3| so that the compressor 2| will operate only as required to supply the pressure fiuid necessary for operating the tool 20.

I claim:

In a controlling device, the combination of a compressor and a motor for driving the compressor, a discharge conduit for conveying pressure fluid from the compressor, a power-controlling device for the motor, means constantly subjected to the pressure prevailing within the conduit and acting responsively to an increasing pressure in the conduit for actuating the power-controlling device to accelerate the speed of the motor, springmeans acting in opposition to the last mentioned means for actuating the power-controlling device to decelerate the speed of the motor in response to a decreasing pressure in the conduit, common linkage for transmitting the forces of the responsive means and the spring-means to the powercontrolling deviceand damping means connected to the linkage and acting to damp both the power-increasing and the power-decreasing movements of the power-controlling device.

FRED M. SLATER.

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