US1153879A

US1153879A - Pneumatic governor.

Info

Publication number: US1153879A
Application number: US64141711A
Authority: US
Inventors: Burton S Aikman
Original assignee: Nat Brake & Electric Co
Current assignee: National Brake & Electric Co; Nat Brake & Electric Co
Priority date: 1911-07-31
Filing date: 1911-07-31
Publication date: 1915-09-21
Anticipated expiration: 1932-09-21

Description

B. S. AIKMAN. PNEUMAT1C GOVERNOR. APPLICATION man 1uLY31.1911.

PatentedSept. 21, 1915.

2 SHEETS-SHED B. S` AlKMAN. PNEUMATIC GOVERNOR. APPUCATION man JULY 3|,.1911.

1,153,879. PntentedSept. 21, 191.3.

2 SHEETS-SHEE 2.

UNITED srars BURTONS. AIKMAN, OF'CHICAGO, ILLINOS, ASSIGNOR. TO

runnin-erro Govnanoa.

Tok all 107mm t may concern.'

Be it known that I, BURTON S. AIKMAN, a citizen of the United States, residing at hicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Pneumatic Governors, of which the following is a full, clear, concise, and eXact description, reference being had to the-accompanying drawings, forming a part of this specification.

My invention relates to controlling devices, more` particularly pneumatic governors, such as are employed in connection with air compressing mechanism to control the starting and stopping of the device for operating the air-compressing mechanism,

.so that a substantially constant pressure In systems of this may be maintained. kind, compressed air is employed as an operating fluid, and, while there are frequent withdrawals from the supply of the compressed air, it is necessary that there be a substantially and practically constant pressure at all times. In the present day, these arrangements are employed very considerably in electric railway systems, particularly for 'the purpose of operating thebrake equipments. vA motor compressor is connected with a supply tank to m/aintain therein a constant supply of compressed air at the required pressure, this tank being connected with the brake cylinders through a valve, and the motor being controlled to start and stop in accordance with certain variations in pressure.

Thesubject matter of my invention is a governing-unit, which comprises essentially a switch and means for closing this switch when the pressure in the supply tank has been reduced to a minimum,and opening it when the pressurehas again reached a predetermined maximum. This switch is either directly in the circuit of the motor for' operating the compressor, or in a local control circuit, automatic means being usually provided for placing the load upon the motor gradually, rather than suddenly. The particular nature of the connection between the controlling unit and the motor does not concern this invention, and I shall make no specific reference thereto. In fact, the entire invention herein is confine to a governor yer se, and thisy description will be so confined, except as it is necessary to refer to the other parts so that the controlling unit itself Specification of Letters Patent.

Application filed July 3l., 1911.

course, apparent that it is only automatically, and

Fatented Sept. 21, 31915. serial no. 641,417.

lt is, of desirable, but in this day absolutely necessary, that the compressor motor be controlled entirely the prior art is replete with devices for securing this result mechanically or electrically.

t is one of the important objects of my. invention to provide a governor which is of simple construction, and which does not rely upon ne marginal operation.

lt is a further object of my invention to provide a governor which will be quick actmay I be properly understood.

NATIONAL BRAKE 85 ELEC- i esv ing, that is, will make and break A the electrical contacts quickly.

lt is also my object to do away with valves as much as possible; in fact, I employ but one valve, and this valve is of simple construction and of positive operation.

lt is my furtherpurpose to provide a device in which the wearing parts are few and are easily accessible for the purposes of inspection and repair.

Other features of construction, arrangement and operation will become apparent to those skilled in the art as this description proceeds.

My invention is embodied in the structureillustrated in the accompanyingv drawings, in which,-

Figure l is a side elevational view thereof; Fig. 2 is a plan view thereof, with the cover removed; Fig. 3 is a sectional view taken on the plane of the line 3 3 of Fig. 2 and looking in the direction indicated by the arrows; Fig. 4 is a sectional View taken' on the plane of the line 4-4 of Fig. E2 and looking' in the direction indicated by the arrows; and F ig'. will be referred to later.

Like reference characters are applied to the same parts throughout the various figures.

The body 6 of the casing is primarily in the form of a shelf, which can be mounted in any suitable manner. rfhis shelf has the

upright side parts

7, 7, ,which are spanned at the top by means of a secondary shelf or bridge 8. The part 6 is provided with a circular opening 9, beneath which a diaphragm l0, of rubber or similar material, is clamped, by means of a casting 1l, bolts l2, 12 passing through the casting 1l and the part 6 in order i to assemble the parts. The casting 1l forms the diaphragm chamber 13, below the' dia- 5 is a detail view which fstem 19,

phragm 10, and this chamber is provided with an outlet 14, extending through a pipe coupling part 15, for connection with the compressed-air reservoir, as will be pointed out'imore fully later.

Mountd upon the diaphragm 10 is the piston member 16, this member having a downwardly extending stem 17 passing through the diaphragm for the reception of a clamping ,nut 18, and in this way the piston is firmly secured to the diaphragm. The pisl ton member haslalso an upwardly extending which is slightly enlarged at the top and which slides with a piston fit in a corresponding alining opening 20 in the bridgef8. A stout coiled springl 21 is disposed between the top'of the piston member 16 and the under side of the bridge 8, a collar 22 intervening, as best shown in Figs. 3 andy 4. The spring is adjusted by screws This spring tends to move the plunger downwardly, and it will be noted that this action is against the working tendency of the pressure in .the reservoir. The downward lmovement of the piston member is positively limited by a cap 23 which-has threaded engagement with the top of the stem 19 and which engages the upper side of the bridge 8, as illustrated in the drawings.

' structure,

This cap has a further function which will be described presently. The piston Vmember has an axial bore 24 extending entirely therethrough, this bore thus opening into the diaphragm chamber 13. Toward the top, the bore 24 is enlarged for the reception of'a thimble 25, which forms part of a valve This thimble is driven in the enlarged part of the bore, and is thus rmly held in place. A tubular member 26 is arranged to slide in the enlarged part of the bore in the piston member, and is provided at its lower end with an inwardly extending flange 27 which supports the valve-seat packing 28, held in place by -means of a plug 29. The flange slides on the outside of the thimble 25 and is provided with by-

passes

30, 30, which are open whenever the v alve packing is off the top of the part 25, and 'closed whenever the valve packing is down upon it.

Secured upon each of the

upright side pieces

7, 7 is a bracket, 31, and these brackets provide bearings forthe shafts 32 and 33. Mounted upon the s aft 32 is a trigger 34, one arm of this trigger extending over the top of the bridge and down into the piston member so as to bear upon the plug 29, as clearly illustrated in Fig. 3. The other arm `of this trigger is engaged on its under sidespring 35 is to raise that arm of the trigger and which I shall term a valve with which it is in contact so as to force the other arm down upon the plug 29. Upon the shaft 33, a circuit controlling lever 38 is mounted, this circuit controlling lever being broadly in the form of a bell crank lever, and having one arm thereof in latch relation withthe trigger 34, as will be described presently. The other arm extends forwardly, and `at its forward end it is provided with a double insulating block 39 secured thereto by means of a screw 40.

spring steel plate 41 is clamped between the two parts of the insulating block, the arrangement being reinforced by a sleeve 42, as shown in Fig. 5, arrangement carries the electric contacrJ member 43. The contact arm which has just been described extends forwardly through a suitable opening into a flaring box 44 of some fireproof material, this` box being carried upon the body 6 by means of

screws

45, 45. The stationary contact member 46 is secured toa connector 47 by means of a 4screw 48, this connector being carried upon the box 44 by means of

screws

49, 49. In Fig. 3 the movable contact 43 and the stationary contact 46 are shown to be in engagement, and it is pertinent to point out at this time that ysuch engagement is against the natural tension of a spring 50 which is disposed between the bridge 8 and the under side of the forward arm of the circuit controlling lever 38. This spring is prevented from expanding by reason of the engagement of the downwardly extending arm o the circuit controlling lever with the shoulder 51 on the trigger A34. The engaging parts just described are reinforced by hardf iocened steel plates 52 and 53, respectively,

since this engagement is an important catch or trigger engagement upon which the operation of the device depends. So long as the trigger 34 is in the position shown in Fig. 3, it will be impossible forthe contacts to separate, and it is not until the spring 50 is allowed to expand that such a result occurs.

i `he cap 23 which has hereinbefore been referred to isprovided upon each side with an upward extension 54, between which a cross rod 55 passing over the circuit controllin lever 38 is mounted. The circuit contro ing lever 38 is provided with a hardened steel wearing plate 5G under-the cross rod 55, so as to form a good wearing surface, since this lever is adapted to be engaged by the rod to bring the electric contacts together in the operation of the device, as will be described presently.

The box 44 is an arc chute for confining the flame that might occur upon the separation ofthe contacts, and in orderto blow out the arc so far as possible, I provide an electro-magnet spool 57 carried upon

side pieces

58, 58 which form magnet poles, and which have

extensions

59, 59 which are megeve clamped in place by the

screws

45, 45. A liber or asbestos barrier 60 is secured in front of the arc chute upon theinside of the hood 61 which incloses the entire mechanism, and which is pivoted at 62 so that it may 'be easily raised to reveal the interior. Upon the front o-f the hood a keeper 62 is provided, and this keeper carries a ring 63 lll' l the other operating so held that the -electromagnet spool.

upon which a spring handle 64 is pivoted. This spring handle has two

engaging surfaces

65 and 66 for engaging a lug 67 on the part 6, and the surface 65is nearer the pivot point than the surface 66. When the ring 63 is swung over the lug 67, the handle is surface 65 may easily slip by the lug 67, and after the ring is in the position'L shown in Fig. 1, the handle is turned back so that the surface 66 will engage the under side of the'lug. This springs the ring, and the parts are held tightly closed. P

' A suitable conductor 68 leads from the spring plate 41, and, guided in an opening 69 in a lug 70 on the body of the device, it passes out of the casing. l The connector 47 has a lead 71 extending therefrom, and this lead connects with one terminal of the The other terminal of the spool is connected with a lead 72, which 'passes out of the casing through an opening in the bushing 73. l l

I shall now describe the operation of my improved device:

It will be remembered that the diaphragm chamber 13 is always at reservoir pressure, and this is through a choke opening. When there is no pressure in the reservoir thel its lower position and all parts are in the position shown in Fig. 3. This is the position which closes together the

contacts

43 and 46, and which thus closes the motor circuit. As the motor operates, the air compressor builds up the pressure in the reservoir, and consequently the pressure inthe diaphragm chamber 13 is'gradually raised. As the pressure builds up, the diaphragm l0 rises against the combined tension of the springs 21-and It will be-seen thatas the diaphragm rises, the piston also rises and the trigger 34 is turned in, a clockwise direction F ig. 3)., so that the area ofthe engagement between the shoulder 51 and the downwardly extending' arm of the lever 38 becomes less and less. When the pressure has risen to a predetermined maximum-that is, when the critical point is reachedthe circuit controlling lever' is released from the shoulder 51 andthe spring 50, now free to expand,

diaphragm 10 is in throws up that side of the lever to place the vthe reservoir at the vrequired pressure-the pressure which is necessary to properly op- .tent, bringing erate the brakes. As the compressed air is used, the pressure is gradually lowered, and it will be understood presently that my device operates to throw the contacts together again when the predetermined minimum pressure has been reached. This operation is as follows: It will be seen that when the downwardly extending arm of thecircuit controllinglever is engaged by the shelf 51a of the trigger 34, the spring 35 can no longer assist the spring 21, and it will be clear that a lesser pressure will keep the diaphragm in its raised position, that is, a lesser pressure than it required to get it there. However, the parts are so adjusted that when the required minimum pressure has been reached, the diaphragm will begin to descend under the influence of gravity and the spring 21. It will be seen that when the diaphragm is in its upper position, the plug 29 of the valve arrangement engages the forward arm of the trigger, and the

bypasses

30, 30 are held closed. Just as soon as the diaphragm begins to descend, however, these by-passes are free to open, since the trigger cannot follow the plug, due to the engagement between the shelf 5ln and the downwardly extending arm of the circuit controlling lever. Thus very quickly does the air in the diaphragm chamber 13 rush up through the bore, 24 and out through the by-

passes

30, 30 to the interior of the casing, which is freely exposed to the atmosphere-and thus very -quickly is the pressure under the diaphragm reduced (due to the choke opening) so that the spring 21 may suddenly expand to a considerable eX- down the pressure, and lowering at the same time the'cross rod 55. This rod engages the forwardly yextending arm of the circuit controlling lever and quickly brings it down so as to close the

contacts

43 and 46 together and to bring the downwardly extending arm of the lever over into such Aposition that the rearward arm of the trigger 34 may spring 35 so that the gage the downwardly circuit controlling lever, the parts being now back in the position shown in Fig. 3. Then again does the motor begin to run and the pressure to rise, as has been described, and the cycle of operations is repeated.

shoulder 51 may en- T claim as new and desire to secure byextending arm of theA rise under the tension of the position, a circuit controlling lever having a catch for limiting the movement of said trigger lever to allow release of the valve upon inward movement of the plunger due to a decrease of pressure in the fluid pressure chamber and means on said plunger to move said circuit controlling lever to release said trigger lever when said plunger moves farther inward, due to release of pressure by opening of the valve.

3. In a' fluid pressure governor, a circuit controlling lever having an open and a closed position, said lever provided with l spring means for biasing the lever toward one of said positions, a trigger for engaging said lever and holding it in one of said positions, said trigger provided with spring means for holding it in engaging position` a movable fluid pressure responsive element for moving said lever, a valve for opening and 'closing a port controlling the pressure on said element, said trigger having means for governing the positionof said valve and a connection between said fluid pressure responsive element and said circuit controlling v lever.

4. In a fluid pressure governor, a circuit controlling lever, said lever aving spring means tending to move it to the open circuit position, a trigger having a latch for holding said lever in closed circuit position, said trigger having spring means for holding the same in position to hold said lever, a movable fluid pressure controlled element, a fluid lpressure chamber communicating with said element, said chamber having a restricted inlet for supplying fluid under pressure thereto, a valve governing an opening in said chamber, said trigger having means for holding said valve in closed position and a connection between said circuit controlling lever and said fluid pressure element.

5. In a fluid pressure governor, a fluid pressure chamber having a restricted inlet, a valve controlling the pressure in said chamber, a movable fluid pressure controlled element, subject to the pressure in`said cham-Y ber, a spring urging said element against the pressure in said chamber, a circuit controlling lever having a spring tending to move it to the open circuit position, a con- 'nection between, said lever and -said fluid.

pressure controlled element, said lever being operated by said first spring through valve being controlled jointly by said trig-l ger and by said fluid pressure controlled element.

6. In a fluid pressure governor, a fluid pressure chamber having a restricted inlet, a fluid pressure element, a spring for movement of said element, a valve on said element, having communication with said chamber, a spring pressed trigger controlled by the movement of said valve, said valve held closed by said trigger, a circuit controlling lever held in closed position by said trigger, a spring to open said circuit controlling lever when said trigger releases the same, said lev'er controlling the trigger to prevent movement thereof, and means connected to said elementto move said lever to closed circuit position when said valve is open.

7. In a fluid pressure governor, a 'fixed and a movable contact, a lever bearing said movable contact, a catch on said lever, a fluid pressure chamber, a fluid pressure controlled element, a restricted inlet opening into said chamber, a valve on said element controlling the pressure in said chamber, a trigger engaging the catch on said lever, said trigger having engagement with said valve, a spring urging said trigger against said valve to retain the same in closed position, said catch of the lever preventing the movement of the means controlled by opening of said valve to move said lever to closed position.

8. In a Vfluid pressure governor, a fixed anda movable contact, a lever bearing said movable contact, a fluid pressure chamber, a fluid pressure controlled'element, a restricted inlet for said chamber, a movable valve controlling the pressure in said chamber mounted on said element, said valve normally closed, a spring controlled trigger, a spring for said trigger, exerting a pressure upon said valve to close the same, and to resist the fluid pressure upon said element, an independent spring resisting the pressure of the fluid upon said element, said circuit controlling lever being provided with a catch engaging said trigger-to render said first spring inoperative to exert pressure on said element.

9. In a fluid pressure govern-or, a circuit controlling lever having a. catch, a trigger for engaging said catch to hold said lever in closed position, a fluid pressure controlled element controlling the lever and the trigsure element, a plurality of resilient means v v element, and a valve cooperating with said Aso y releasing the pressure in said trigger, a spring for pressing said trigger for resisting the movement of the fluid pressure element, a spring for said lever forcing the lever to open position when said trigger is operated, one of said resilient means being connected to said trigger, and rendered inoperative to eXert a resisting pressure upon said element when ,the trigger is operated, and a connectionA between said element and the lever for moving the lever to closed circuit position.

10. In a pneumatic governor a stationary contact, a lever, a movable contact mounted on said lever, spring means urging said lever to open circuit position, a trigger having a latch controlling said lever, a fluid pressure controlled means to trip said trigger, a spring for holding said trigger in position to catch the lever, said spring opposing the movement of said fluid pressure means, a valve seat on said fluid pressure seat, said valve being held upon its seat by said trigger.

11. In a fluid pressure governor, a stationary contact, a lever, a movable contact mounted upon said lever, spring means urging said lever to open circuit position, a trigger having a latch for holding said lever in closed circuit position, a fluid pressure chamber having movable pressure controlled means to trip said trigger, a resetting connection between said lever and said fluid pressure controlled means, spring means operating through said resetting connection upon-reduction of pressure in saidchamber to reset the circuit controlling lever and valve means controlled by said trigger forreducing the pressure upon said fluid pressure means.

12. In a fluid pressure governor, a'iiuidv pressure chamber. a diaphragm forming a wall of said chamber, a piston member connected to said diaphragm, aspring tending to force said piston inward, a pivoted trigger lever, a valve having a seat on said piston, said valve controlling the pressure in said chamber, a spring pressing said trigger into engagement with said valve to holdf same on itsseat on said piston to assist in the inward movement of said piston, contact mechanism controlled by said trigger, and means for operating said contact mechanism, and for cutting said second named spring out ,of action when the piston has been moved a predetermined amount.

13. In a fluid pressure governor a vfluid pressure chamber, a movable fluid pressure responsive element subject to the pressure in said chamber, a spring tending to move said element inward against v`said fluid pressure, a valve having a passage communicating with said chamber, opening of said valve chamber, a

'against said valve and tending to move said said chamber,

pressure chamber, having a restricted inlet,

a piston member subject to pressure in said chamber, a spring tending to move said piston inward, a valve on said piston, said valve having a passage for releasing the pressure in said chamber, a stationary contact, a lever having a movable contact, a trigger having a latch for engagingsaid contact lever, a connectionbetween said piston member and said trigger, and la connection between said lever and said spring.

15. In a fluid pressure governor, a circuit controlling lever, a catch for said lever, a trigger, a catch on said trigger for cooperating with the catch on said lever, a spring for said trigger, said spring tending to hold said catches in engagement, a fluid pressure chamber, a fluid pressure controlled element movable by increase of pressure in said chamber to trip said trigger,a spring for said element to resist the pressure in said chamber, a spring for said circuit controlling lever, said latter spring tending to move said lever to open circuit position, a valve communicating with said chamber, said valve being operable to relieve the pressure in said chamber and being normally held closed by said trigger, said valve having a valve seat upon said movable element and a connection between said Huid pressure element and said lever.

In a fluid pressure governor, a fluid pressure chamber, a movable fluid pressure controlledelement governed by pressure in said chamber, a valve, a port communicating with said chamber, said port being controlled by said valve, a circuit controlling lever, a spring therefor, a trigger lever, a lspring-therefor, saidcircuit controlling le- .ver and said trigger lever having interlocking means, a connection from said pressure controlled element to said circuit controlling lever and a connection between said trigger and said pressure controlled element.

In a fluid pressure governor, a fluid pressure chamber, a. movable pressure controlled element, subject to the pressure in a valve `for relieving the pressure in said chamber, a spring for moving said element inward, a trigger, a spring for said trigger, said spring resisting the out- Ward movement-of said element and holding said valve upon its seat, aI circuit controlling lever normally held in closed position aby said trigger and an operative connection from said element to said lever.

18. In a fluid pressure' governor, a fluid preSSllre chamber, a'piston member subject to the pressure in said chamber, a spring Jfor moving said piston inward, a stem connected to said piston, a valve on said stem, a passage through said stem connecting said valve and said chamber, a trigger lever pivoted at a lixed point adjacent, said stem, and having one arm bearing upon said valve, a spring connected to said lever tending to hold said valve against its seat, and to moveV said piston member inward, a catch on said trigger, a circuit controlling lever, a catch on said lever for interlocking engagement with the catch on said` trigger, a spring tending to move said circuit controlling lever toopen position and a loose coupling between said piston stem and said circuit controlling lever to move the lever to closed circuit position.

19. In a fluid pressurel governor, a fluid pressure responsive element, a circuit controlling lever, a trigger for holding said lever, said trigger controlled by the fluid pressure element, and a valve` governing the fluid pressure on said fluid pressure element, operation of said valve being controlled by said trigger.

20. In a lf'luid pressure governor, a fluid pressure chamber, a movable fluid pressure responsive element, controlled 4by pressure v second position, and a tion, a pressure in said chamber, a valve controlling the pressure in said chamber, an operative element'having two positions, a trigger for holding saidfoperative element in one posi-v tion, a spring to move said element'into its loose coupling from said fluid pressure element to move said operative element to its first position, said valve controlled by said trigger.

.21. In a fluid pressure governor, a switch lever provided with a latch, means for biasing said switch to-,open position, a trigger engaging said latch to hold the switch closed means biasing said trigger to latching posichamber having a movable wall, an inlet and an outlet, resilient means acting on said wall in opposition to the pressure therein, a valve for said outlet and means co-acting with said movable wall and trigger for holding the valve closed and operating said trigger to release said latch upon increase of pressure in said chamber.

In witness whereof, I hereunto subscribe my name this 27 th day of July, A. D. 1911.

BURTON S. AIKMAN.

Witnesses:

ARTHUR I-I. BoE'r'roHnn, R. II. WEILAND.