US2551429A - Safety trip device for motors responsive to temperature, speed, and pressure - Google Patents

Description

May 11, 1951 E. G. EPPENS SAFETY TRIP DEVICE FOR MOTORS RESPONSIVE T0 TEMPERATURE, SPEED, AND PRESSURE 2 Sheets-Sheet 1 Filed Nov. 19, 1948 INVENTOR ERNEST G-EPPENS. BY

HIS A ORNEY.

May 11, 319511 E. e. EPPENS SAFETY TRIP DEVICE FOR MOTORS RESPONSIVE TO TEMPERATURE, SPEED, AND PRESSURE 2 Sheets-Sheet 2 Filed Nov. 19, 1948 INVEN TOR ERNEST G. EPPENS. BY Z1! 1 HIS ATTORNEY.

Patented May I, 1951 SAFETY TRIP DEVICE FOR MOTORS RE- SPONSIVE TO TEMPERATURE, SPEED,

AND PRESSURE Ernest G. Eppens, Phillipsburg, N. J., assignor'to Ingersoll-Rand Company, New York, N. Y., a. corporation of New Jersey Application November 19, 1948, Serial No. 61,000

' This invention relates to safety devices for motors and more particularly to a device for shutting off a motor in the event its temperature or speed becomes excessive or the oil pressure becomes too low.

It is one object of this invention to combine the speed, temperature and oil pressure control devices into one simple compact unit.

It is a further object to provide a single control arm for starting, stopping and resetting the control device.

' Other objects will become apparent in the following specification and accompanying drawings in which:

Figure 1 is a side view, partly in section, of a control device constructed in accordance with the practice of the invention,

' Fig. 2 is a top view of Figure 1,

Fig. 3 is an end view of Figure 1,

Fig. 4 is a transverse view taken through a detail of Figure 1 along the line 4-4 looking in the direction of the arrows, and

Fig. 5 is a transverse view through a detail of Figure 1 taken along the line 5-5 looking in the direction of the arrows.

Referring to the drawing and more particularly to Figure 1, a preferred form of the safety mechanism is shown adapted to a motor, a portion of the casing I of which is shown. The safety mechanism comprises, in general, devices ll, [2 and I3 responsive, respectively, to abnormal conditions of speed, temperature or oil pressure of the motor to actuate a lever [4 thereby releasing a control rod which effects the shutting down of the motor by actuating a device 22 of any conventional form, depending on the type of motor to which the safety mechanism is adapted, for stopping the motor. A control handle I6 is provided to reset the control rod [5 after it has been released by one of the control devices and it also serves as a manually operated means for releasin the control rod 15 for stopping the motor.

More specifically, the safety device includes a plate I l secured to the casing [0 by bolts I8 and on which the various automatic control devices are mounted. In furtherance to this end, a support member i9 projects from the plate I! and slidably encircles the end portion of the control rod l5 disposed to rotate a lever 20, keyed to a shaft 2|, by which the motor shut down device 22 is actuated. For the sake of illustration,

this device is shown as being a fuel valve, the' 4 Claims. (Cl. 601) right (Fig. 1) or rearwardly direction effects clockwise rotation (as viewed in Fig. 1) of the shaft 2| to close the fuel valve 22. The opposite or forward end of the control rod I5 is supported by a screw 24 threaded in the plate I! and having a transverse hole 25 through which the rod l5 slidably extends. The body portion of the screw 24 serves as an axis or pivot for the hub 26 of the lever l4. Rotation of the lever [4 in a clockwise direction, as viewed in Fig. 1, effects engagement of an abutment 21 on the lower edge of the lever I4 with a shoulder 28 on the rod l5 to retain the rod l5 in its forward position wherein the operation of the fuel valve is independent of the safety device.

On the rearward end of the lever 14 is a cam 29 having an inclined surface 30 which cooperates with the complementary inclined surface 3| on the control handle l6, rotatably mounted on a pin I threaded in the plate [1, in such a manner that when the handle [6 is rotated to its rearward limiting position, the lever I4 is forced upwardly or counterclockwise to release the control rod l5.

Slidablymounted on the housing [0 below the cam 29 and in line therewith is a pin 32 which cooperates with the speed control device H to lift or rock the lever and release the control rod l5 whenever the speed of the motor becomes excessive. To this end, an over speed device II is provided to actuate the pin 32 and, in this instance, comprises an annular plate 33 keyed to a countershaft 34 on which is pivotally mounted a weight 35. The Weight 35 is mounted ofi center so that it tends, due to centrifugal force, to swingoutwardly against the force of a spring 36 to strike the lower end of the pin 32 whenever the motor speed exceeds a predetermined value. Interposed between the end of the pin 32 and the counterweight 35 is a lever 31 to transmit the movement of the counterweight 35 to the pin 32. A set screw 38 engaging the opposite end of the lever 31 serves to regulate the space betweenj' the counterweight 35 and the end of the lever 31 which it strikes, thereby effectively regulating the maximum speed of the motor. The speed at which the counterweight 35 moves out suificiently to strike the lever 31 and move the pin 32 to release the control rod I5 is, of course, dependent on the strength of the spring 36 and the setting of the screw 38.

' Disposed on the opposite or forward end of The forward' end 42 of the rod I5 bears in the other cup 40. As is best seen in Figure 1, the pin 39 is somewhat out of line, in this instance slightly above, with respect to the forward end 42 of the rod I5-- thus, the spring 4| serves as a means for urging the controlrod I5 into its rearward position to effect the closure of the fuel valve and also, due to the previously mentioned misalignment, serves to urge the lever I4 into engagement with the control rod to prevent said rearward movement of the rod I5.

Extending vertically upward from the lever I4 and integral therewith is a projection or arm 46 which is actuated by the temperature responsive device I2 for rocking the control lever I4 to re lease the rod I5. In furtherance to this end, the device I2 includes a casing 43 for a reciprocative plunger 44, the stem 45 of which bears against the free end of the arm 46 which it actuates. Movement of the plunger 44 to release the rod I5 is effected by the thermal expansion of a fluid in a bulb or ball 41 positioned at a point in the motor casing I where it is desired to keep the temperature below a predetermined maximum and communicating with the plunger chamber 48 through a conduit I46. In order to obviate the need for a tight fit between the plunger 44 and the casing 43 and between the stem 45 and the casing 43, a Sylphon 49 is attached to the forward end of the casing and secured at the other end to the forward surface of the plunger 44 thereby preventing any leakage of fluid from the casing 43 along the stem 45. A spring 50 encircling the stem 45 within the sylphon 49 biases the plunger 44 towards its normal rearward position.

On the side of the arm 46 opposite the stem 45 and mounted on the projection integral with the plate I! is the oil pressure responsive device I3 comprising a cylinder for the spring pressed piston 53 exposed on one side to the oil pressure of the motor through a conduit 54. On the opposite or rearwardly side of the piston 53 is a stem 55 extending beyond the rearward edge of the arm 46 and having a transverse pin 56 in its end to engage the arm 46. With this arrangement, whenever the oil pressure within the motor drops below a predetermined value, the spring 51 will force the piston 53 forwardly or to the left, as viewed in Figure 1, and the pin 56 will rock the arm 46 of the lever I4 to release the control rod I5.

In order to prevent the pressure control I3 from releasing the control rod I5 before the oil pressure of the motor builds up, when starting the machine, a bell crank 58 pivotally mounted on a pin 59 supported by a bracket 66 of plate I1 is provided which at one end engages the pin 56 and the other end is in alignment with the control handle I6 so that when the handle I6 is in its forward limiting position, an abutment 6| on the handl I6 contacts the lever 58 to hold the piston 53 in a rearward position against the pressure of biasing spring 51 thereby preventing the oil pressure device I3 from shutting off the motor before the oil pressure has increased sufficiently to overcome the spring 51.

The control handle I 6, as previously mentioned, serves to reset the control rod I5 and to this end is provided with a pin 62 which lies in the path of the shoulder 28 so that movement of the control handle I6 to the left (Fig. 1) brings the rod I5 into a position to be engaged by the abutment 21. At this point, the pin 62 is retracted from the path of the shoulder 28 by the action of a shoulder 63, on the pin 62, which rides on a cam 64 4 mounted on the plate I1. A spring 65 interposed between the shoulder 63 and the handle I6 assures continuous contact between the shoulder 63 and the cam 64. Thus, the lever I4 may be advanced further to bring the abutment 6| into contact with the bell crank 58 in the manner previously described, to hold the piston I5 in its rearward position. This cam arrangement serves, further, due to frictional resistance to movement between the cam 64 and the shoulder 63, to retain the control handle I6 in any position that it is set by the operator.

Briefly reviewing the operation of the control device, in order to start the motor, the control handle I5 is rotated into its forward limiting position thereby moving the control rod I5 into a position wherein it is engaged by the shoulder 21 and restrained from reverse longitudinal movement, and the oil pressure device I3 is restrained from tripping the control rod I5 until such time as the motor oil pressure builds up to its operating value. At this time, the handle I6 is rotated in the reverse or clockwise direction thereby releasing the oil pressure device I3 to operate in accordance with the motor oil pressure, and the rod I5 is free to move in a rearward direction to shut down the motor whenever it is released by the lever I4. As long as the rod I5 is retained in its forward position by the shoulder 21, the fuel valve 22 is free to be actuated in accordance with the speed of the motor or any other control device (not shown) to which it may be operatively connected. Upon any abnormal condition of pressure, temperature, or speed, the lever I4 is rocked in a counterclockwise direction, as viewed in Figure 1, by the appropriate control device to release the rod I5, which under the influence of the spring 4! overpowers any speed regulating device (not shown) to which the fuel valve 22, or other motor shut down device, may be connected to shut oil the motor. The strength of the spring 4| is also sufficient to rotate. the lever I4 in the event it is inadvertently left in a position wherein the pin 62 is in line with the shoulder 21. In the event that it is desirable to halt manually the operation of the motor, it is merely necessary to move the lever I4 into its rearward limiting position thereby rocking the lever I4 to release the rod I5 in a manner described in detail hereinbefore.

It is now obvious to those skilled in the art that a safety device constructed in accordance with the practice of the invention attains, among others, the objects hereinbefore stated and provides a relatively simple yet highly compact device which is responsive to a plurality of operating characteristics of a motor to shut down the motor in the event of an abnormal or dangerous condition in the motor which effects any one of these characteristics and, further, any or all of these devices may be reset by the simple expedient of rotating a single lever.

While I have shown and described a specific form of my invention, it is to be understood that various changes and modifications may be made without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. In a safety mechanism for motors, a valve for controlling the flow of fuel to the motor, a rod movable longitudinally'to close said valve, a lever engaging said rod against such longitudinal movement, means urging said rod into position for actuating said valve to stop the motor and urging said lever into engagement of said rod,

a device responsive to the motor temperature for actuating said lever to release said rod, a device acting responsively to the oil pressure of the motor to actuate said lever to release said rod, a device acting responsively to the speed of the motor to actuate said rod, and a control handle acting upon movement in one direction to reset said rod and acting in the other direction to efiect the release of said rod.

2. In a safety mechanism for motors, a valve for controlling the flow of motive fluid to the motor, a rod movable longitudinally to actuate the valve to shut ofi the motor, a pivot, a lever rotatably mounted on the pivot for engaging the rod to prevent longitudinal movement thereof, means for urging the rod to move longitudinally and for rotating the lever into engagement With said rod, an arm on the lever, and a plurality of devices acting in response to abnormal conditions of various operating characteristics of the motor for engaging said arm to rotate the lever out of engagement with the rod.

3. In a safety mechanism for motors, a valve for controlling the flow of motive fluid to the motor, a rod movable longitudinally to actuate the valve to shut off the motor, a pivot, a lever rotatably mounted on the pivot for engaging the rod against longitudinal movement, means for urging the rod to move longitudinally and for rotating the lever into engagement with said rod, an arm on the lever, a plurality of devices acting in response to abnormal operating characteristics of the motor for engaging said arm to rotate the lever out of engagement with the rod, and a handle to reset the rod upon movement in one direction and for disengaging the lever from the rod upon movement in the opposite direction.

4. In a safety mechanism for motors, a valve for controlling the flow of motive fluid to the motor, a rod movable longitudinally to actuate the valve to shut off the motor, a collar on the rod, a pivot, a lever rotatably mounted on the pivot having a shoulder for engagement with the collar on the rod to prevent longitudinal movement of the rod, a spring for urging the longitudinal movement of the rod and for rotating the lever into engagement with the rod, a plurality of arms on the lever, a plurality of devices acting in response to abnormal operating characteristics of the motor for engaging the lever arms to rotate the lever out of engagement with the rod, and a handle adapted to engage the collar on the rod to reset the rod upon movement in one direction and adapted to engage an arm on the lever to disengage the lever from the rod upon movement in the opposite direction.

ERNEST G. EPPENS.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,989,230 Everett Jan. 29, 1935 2,201,123 Davis May 14, 1940 2,225,234 Schettler Dec. 17, 1940 2,423,728 Ray July 8, 1947

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