US1287481A - Speed-governor. - Google Patents

Description

A. D. SKINNER.

SPEED GOVERNOR.

APPLICATION FILED DEC.29. 19w.

Patefited Dec. 10, 1.918.

3 SHEETS-SHEET ll I T N ESS E S 26%. a. [gVlfNTOR BY im Q4 TTO/HVE Y.

A. D. SKINNER.

SPEED GOVERNOR.

APPLICATION FILED DEC.29, I917.

D Patented Dec. 10, 918.

3 SHEETSSHEET 2- ALLAN D. SKINNER, OF ERIE, PENNSYLVANIA.

SPEED-GOVERNOR.

Specification of Letters Patent.

Patented-Dec. 10, 1918.

Application filed December 29, 1917. Serial No. 209,427.

To all whom it may concern: I

Be it known that I, ALLAN D. .SKINNER, a citizen of the United States, residing at'Erie,

in the county of Erie and State of Penna,

automatic governorfor controlling admis-' sion valves and it may be applied to steam or other engines. An automatic governor will control the operation of an engine within certain limits, but for some classes of service, such as where the engines are operating compressors, pumps or fans, it is desirable and necessary at times to vary the speed of the engine according to the desired output of the compressor, pump or fan, beyond. the range of the ordinary automatic governor.

Heretofore this has ordinarily been done in various ways which are objectionable in some respects, suchas by various hand operated cutoffs, or by stopping the engine and changing the weights or tension of the springs of the governor,- or by the use of a throttling governor. p

The present invention provides means for varying the speed within rather widelimits, and according to the load, said means being additional to, and in some respect independent of, the ordinary or normal governor mechanism. i

- The invention requires no more valve gear than a shaft governor engine" built for constant speed, and has a further advantage that it operates while the engine is running, being supplemental to the normal action of the governor.

The invention embodies the use, in one of its forms, of an electric motor, which iscarried by the governor and which is controlled by devices actuated according to load or desired conditions, to Varythe position of the lever arm of the governor, to thereby vary or shift the valve operating mechanism and accordingly the valve travel.

The invention also involves certain improved details of construction as will be more fully apparent from the following description.

In the accompanying drawings,

Figure 1 1s a diagram of the controlling system applied to an engine and a pump.

Fig. 2 is a side ele ation of the shaft governor with parts of the invention applied thereto.

Fig. 3 is a section of the line 33 of Fig. 4 is an enlarged detail of the bearing of the governor arm.-

Fig. 5 is a section showing the pressure controlled switch which controls the circuits of the electric motor. s I

Fig. 6 is an end view of Fig. 5.

Referring specifically to the drawings, A indicates an engine and B a rotary pump driven thereby; C is a fly wheel and D is a belt therefrom to the pump. The valve gear has been omitted from the drawing but it will be understood that the engine is provided with such gear as usual, this gear being operated by the shaft governor which is mounted on the fly wheel C as shown in Fig. 2. Although illustrated in connection with a pump, the invention could be used in connection with a fan or any other load, no limitation in this respect being implied.

The governor arm is indicated at 6 mounted on the wheel C by the suspension pin 7, and the outer end of this pin is hollowed to receive the hub 8 of the eccentric arm 9 which is held on the pin by a bolt 10.

Roller bearings 11 may be used between the pin and the arm if desired. The arm 6 carries the Weights 12 and 13 and is con-' nected to the governor spring 14 which is attached to the governor wheel in the usual manner, but not shown, these parts being of standard type, such for example as shown in the patent to Skinner No. 628591.

15 is a long travel stop on the wheel for the governor arm 6, and '16 is the short travel stop for-"the 'same,

The eccentric arm 9 carries a pin 17 which is connected to and'operates the admission valve gear (not shown) in the usual manner. This arm has heretofore formed an integral part of the governor arm 6, but in the present invention this arm may be moved angularly relative to the said arm 6, whereby the valve travel may be varied independently of or supplemental to the position of the governor arm, the eccentric arm being (except when its position is varied by the m o tor') locked in relation to the governor arm.

This relative variation in the angularity of the two arms is accomplished by an electric motor 18. This motor is mounted on a bracket on the governor armand its armature, is connected or geared to a non-traveling'screw 19 which is supportedby a suitable bracket 20 on the arm. 21 1s a nut-or threaded block which travels on the screw '19, andthis nut is connected by a link 22 to the end of the eccentric arm 9 as shown opposite the Wrist pin 17. It will be seen that the angular relation of thearms 9 and 6 may be varied by rotation of the screw by the motor, the nut 21 traveling along the screw 1 pin 17 independent of any variation inci-- dent to the posit on and thereby varying the eccentricity of the of the main governor tl-Tm 6. l L- This motor is Wired as indicated at 23 to I collector rings 24 on the hub of the fly wheel,

and these rings receive current from brushes 25 which are preferablv connected by wiring 26 to relays 27 and 28 in the high voltage line 29. The wiring is so arranged that the motor 18 can'be reversed, one of. the .re- 7 lays being connected to give the direct drive and theother to give the reverse. drive, and these relays are preferably connected to a low voltage line 30 whichcontains a circuit changer or switch indicated at 31 controlled by a pressure actuated device lndlcated at 32 which is controlled by pressure or other load, conditions. I

In the device illustrated for thepurpose of this description, the controlling device- 32 comprises a cylinder containing a piston 33 pressed in one direction by a spring :54, and carrying a sliding switch piece 35 with a cross bar 36 01. conductingmaterial which" closes the pairs of terminals 37 and 380mnected respectively to the relays 27 and 28;

- or the switch bar may rest in'neutral position between the two pairs of terminals. On

the side of the piston opposite the spring the cylinder is connected by a pipe 39 to the outlet pipe 40 from the pump B, whereby the. piston is subjected to the discharge.

*the eccentric pin 17 to the long travel position, as usual in governors of this type. WVhen. the engine isstarted the arm will remain in said position until the engine reaches'a predetermined speed, whereupon the centrifugal action cau'ses it to leave the;

' stop 15, giving-a constant speedirrespective of the load, within the maximum capacity of the engine, and. when the engine carries no load but its own friction, the governor arm will swing toward-or agalnst the stop i 16. This is the standard operation of a governor of this type, which thus provides a limit to the'speed of the engine, -As stated above, under certain condltlons it .is desirable t reduce thespeed of the engine below the set speed of the ordinary automatic governor.

' Thus should it bedesired to reduce the speed by means of the separate control the switch 31 may be operated to close the circuit of the motor 18 and drive'the same in such direction as to draw the block 21 toward the motor, and toward the right as swing the arm 9 relative to the arm 6 and to-shift the wrist pin 17 toward the short travel position. In other words it varies the relation between the valve gear and the shownin Fig. 2, and the effect of this is to governor arm 6. This action would other wise result in the shortening of the valve travel, thereby decreasing the speed of the engine, but is automatically compensated for by the governor arm 6 assuming anew position nearer the 'stop 15. That is to say, the if normal action of the governor,- tending to keep the engine at constant normal speed'for which it was set, causes the lever 6 to assume a new. position nearer the long travel stop 15-and the pin 17 is thereby held in the same eccentric relation to the shaft as it was before the adjustment was made. Then by still further shifting the eccentric arm 9 in the direction stated, the governor arm 6 will finally rest against the stop 15, and

a further shifting of the arm 9 toward the short travel position can no longer be compensat-ed by further movement of the arm 6, and therefore the speed of the engine will necessarily be reduced by the shortened valve travel, admitting less steam to the engine. In other words, after the lever 9 has reached the stop 15, the normal action of the governor has been overcome and further movement of the arm 9 in the direction stated results in shortening the valve travel and reducing the speed. Should the load of the engine be sufliciently reduced or. removed when the eccentric arm 9 is in the position just described the engine will speed up until it reaches the speed to whlch the governor is set, where'- upon the governor arm 6 will leave the stop 15 by reason of the usual c ei'itrifugalaction, and the eccentric .arm 9 willswing with thegovernor armtoward the short travel positionuntil the steam admitted correspondsto the reduced load, when the Farms will. resume their usual function and will act as a speed limit stop.

lVhen the engine is running at the reduced speed should it be necessary or desired to increase the speed of the engine, the

control switch 31 will be shifted in the opposite direction from that above explained, and by the electrical connections the motor 18 will be driven in a direction to shift the block 21 to the left in'Fig. 2 and the effect of this willbe to swing the eccentric pin 17 toward the-long travel position, thereby increasing the valve travel and the speed accordingly, in almanner the reverse of that described above, until the engine obtains the speed for which the governor Was set, whereupon the governor arm leaves stop and the governor resumes its normal functions. In order to prevent any increase of speed abovethat to which the governor is set, the bracket 20 is so located that it acts as a stop for the movement of the block 21 to the left in Fig. 2, similarly to the stop 41 with respect to movement to the movement in that direction, so as to avoid burning out the motor.

It maybe stated here that the eccentric arm 9 has an extension 9 on the outer end thereof, and the wheel 0 has a stop 41 for said extension, which is so placed, that when the arm 9 is in its position'of least travel, the extension 9 will stopagainst the part 41 and will prevent thearin- 9' from swinging beyond the least travel position into a position which would reverse the direction ofrotation of the engine. That is, assuming that the-engine is operating at a speed less than the maximum speed to which the ,governor' is adjusted, and assuming that the arm has been moved toward the short travel position, if the load should be reduced or thrown off entirely the arm 6 wo'uldimmediately swing toward-the short travel stop 16, which, were it not preventedby the extension 9 striking the stop 41 in advance might throw the eccentric arm into sulting in reversing the engine.

It will-be seen that by means of this device the speed of the engine may be varied as desired below the normal speed for which the governor is set; that the engine cannot be reversed in its rotation, and that its -'a position beyond the shortest travel, re-

speed cannot be increased beyond the limit to which the governor is adjusted.

It will be appreciated that the controlling switch may be operated by hand, or it may be operated by the automatic device illustrated, or by other automatic device controlled by pressure, volume or velocity of fluids actuated by a machine driven by the engine.

when the pressure admitted through ,the pipe 39 exceeds thetension of the spring 34 the piston will be driven to the right until lay 28 the motor will be driven in such a direction as to reduce the speed of the engine and consequently the work of the pump. And in likef manner, if the discharge pressure of the pum decreases to such an extent that the spring shifts the switch to the other position, as shown in Fig. 5, the contacts 37 will be closed, operating the relay 27 and driving the motor 18 in the reverse direction, thereby shifting the arm 9 and increasing the speed of the engine and the work of the pump. The spring 34 will be adjusted according to the pressure desired so that, normally, the switch will be in neutral position, with the connector 36 in the space between the terminals 37 and 38. The positionof the said terminals may be adjusted by the screws 50 so as to increase or decrease the gap between the terminals and thus permit as much variation in pressure as desired, before the motor comes into operation.

The relays might be omitted-and the motor circuits connected directly to the switch, but relays are preferable where high voltage is used. It; is to be understood that the adjustment of the movable eccentricv arm may be effected by an electric motor, a fluid with the shaft one of which is.adapted for attachment to a valve gear, of means to adjust said connection to vary the relative a'n-Q gularity of the levers.

- 2. The combination with a shaft governor including two connected levers revolving with the shaft one of which is adapted for attachment to a valve gear, of means to adjust said connection to vary the relative angularity of the levers, said means including an electric motor carried by one of the levers and 'operatively connected to the other.

3. The combination with a shaft governor including a weighted governor arm' and an eccentric arm revolving with the shaft, said arms being pivotally mounted with respect to each other, of electrically operated adj ustin'q' devices connecting the two arms and operable to vary the relative angularity of the arms.

4. The combination with a governor including a weighted governor arm and an cecentric arm, said arms :being pivotally mounted with respect to each other, of an electric motor mounted on one of the arms, Thus in the controlhng device illustrated,-

a screw drlven by the motor and operatively connected to the other arm, and means to 6. The combination with a shaft governor mechanism including an eccentric arm adapted for connection to a valve gear, of a modifying mechanism including an electric motor carried by the governor and operatively connectedto said arm to vary the angularity thereof, circuit connections to said I motor, including a rotary collector, and a switch in said circuit, and means automatically actuated by the load on the engine to operate the switch.

1 7. The combination with a shaft governormechanism including an eccentric arm adapted for connection to a valve gear, of a modifying mechanism therefor including a reversible electric motor carried by the governor and operatively connected to one of the governor parts to vary the angularity thereof, circuit connections to said motor,

and a reversing switch in said circuit connections, and means automatically controlled by the load on the engine to operate the switch.

8. The combination with a shaft governor including two connected levers revolving with the shaft one of which is adapted for attachment to a valve gear, of means to -au-' tomatically adjust the angularlty of one of the levers with respect to the other,-and a stop engageable by the adjustable lever to limit the extent of its adjustment.

In testimonywhereof, Iatfix my signature in presence of two, witnesses.

ALLAN D. SKINNER.

Witnesses: ALBERT E. ROSE,

GEO. E. TEW.

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