US2793337A - Control system for sequential operation of pump motors - Google Patents

Description

7 Sheets-Sheet l J. J. DELANEY ET AL ATTORNEY W w .H W JT N fl 0 R 3M4 CONTROL SYSTEM FOR SEQUENTIAL OPERATION OF PUMP MOTORS Filed Feb. 16, 1953 May 21, 1957 y 1957 J. J. DELANEY ETAL 2,793,337

CONTROL SYSTEM FOR SEQUENTIAL OPERATION OF PUMP MOTORS Filed Feb. 16, 1953 7 Sheets-Sheet 2 JoHN J. DELANEY ALBERT F RoMANowsm INVENTOR.

ATTORNEY y 1957 J. J. DELANEY ETAL 2,793,337

CONTROL SYSTEM FOR SEQUENTIAL OPERATION OF PUMP MOTORS Filed Feb. 1a. 1953 7 She ets-Sheet 3 has JOHN J. DELHNEY ALBERT F. Romnnowsm INVENTOR.

RTTORNEY y 1957 J. J. DELANEY ET AL CONTROL SYSTEM FOR SEQUENTIAL OPERATION OF PUMP MOTORS Filed Feb. 16, 1953 7 Sheets-Sheet 5 m m mm mm Rom uRm DE m NE mm JR y 1957 J. J. DELANEY ETAL CONTROL SYSTEM FOR SEQUENTIAL OPERATION OF PUMP MOTORS Filed Feb. 16, 1953 '7 Sheets-Sheet 6 mom m m/ V Nm m0] ER DE .NE H5 km M HTTORNEY y 1957 J. J. DELANEY EIAL 2,793,337

CONTROL sys'mu FOR SEQUENTIAL OPERATION OF PUMP MOTORS Filed Feb. 16 1953 7 Sheets-Sheet '7 JOHN J. DELHNEY HLBERT F. Ronawowsm INVENTOR.

BMW

United States Patent '0 CONTROL SYSTEM FOR SEQUENTIAL OPERATION OF PUMP MOTORS John J. Delaney-and Albert ERomanowski, Fort Wayne,

Ind., *assignors toBowser, Inc.,"Fort Wayne, IniL, a corporation of Indiana Application February 16, 1953, Serial No. 337,013

18 Claims. (Cl. 318-102) service stations, there may be anywhere from four to six or more dispensing pedestals connected to receive liquid from a tank. Tosupply the proper amount of liquid to the pedestals which are operating may require one or two pumps since while one to say five pedestals of eightmay be in operation at one time. At no time in the operation of such a station would it be likely that. all of the pedestals would be in operation. The number of operators would, in itself be a limiting factor as would the fact that not all customers would demand the same grade of fuel and the different grades, of course require a separate pumping system.

The fact that the pedestals do not include the usual pump and motor and their appurtenances reduces the. cost of'the pedestals whereas the pumping mechanism itself has only two pumps and motors. Thus in a system using eight or even more pedestals, there is a. saving of six or more pumps and six or more motors. These units are expensive and the saving is considerable.

Present day gasolines are being made with higher vapor pressures .so'that the imposition of a high lift or resistance to flow on the suction side of the pumps results in pulling the gasoline apart and the pumping systems become vapor locked. Flow of liquid ceases and the system is inoperative.

A further advantage of this system is that the pumps can be installed closely adjacent the tanks so that the resistance'to flow on the suction side can be reduced to a minimum and the liquid can be delivered through the long runs of pipe leading to the various pedestals under pressure.

Another advantageof the system is that the suction lines are not run horizontally for long distances near the surface of the ground or driveways so that they and the liquid inthem can absorb heat from the sun as in the case where each'dispenser has its own pump and motor.

These and other objects will become apparent from a study of this specification and the drawings which are attached hereto, form a part hereof and in which:

Figure 1 is an elevation of the pumping apparatus.

Figure 2 is a plan view of the pumping apparatus.

Figure 3 is anelevation of the pumping control apparatus.

Figure 4 is a schematic view of the hydraulic and electrical portions of the entire system.

Figure 5 is an end view of the control apparatus.

Figure 6 is a detail view or" the primary switch.

Figure 7 is an elevation, partly in section, of the back pressure valve.

Figure 8.,is an elevation of a modified form of control apparatus.

Figure 9 is an elevation, partly in section, of the apparatus ofFigure .8. I

Figure 10,is a sectional view taken substantially on line 1010 of Figure 8 showing the actuating mechamsm.

Figure 11 is asectionalview of the air separator vent taken substantially on line 1111 of Figure 2.

Pumping system Referring first to Figure 4, the system comprises the tank 1, which has a foot valve 3, a suction line 5 which is manifolded by branches 7, 9 to the pumps 11, 13. The discharge pipes 15, 17 from the pumps pass through the gas separators 19, 21 and back pressure valves 23 25 to acommon discharge line 27. Line 20 carries the gas and liquid discharged from the gas separators to the tank.

Pedestals 29, 31, 33, 35, 37, 39, 41, 43 and 45 are all connected to receive liquid from the line 27.

Each pedestal is provided with the usual meter, hose,

.nozzle, sight glass, register, interlock, hose hook and other parts which are commonly employed in such apparatuses. Each hose hook is connected to a switch and serves to close it when the hose nozzle has been removed from the hose hook and the switch lever has been manipulated to its on position.

All ofthis structure is old in the art and pedestals of the kind described have beenrnarketed by the gasoline pump industry for a number of years.

The switches referred to as being closed and opened by the switch levers are here numbered 47, 49, 51, 53, 55, 57, 59, 61 and 63.

The power supply mains are indicated by numerals 65, 67. Main 65 is the neutral wire and is connected to one contact .ofall of the aforesaid switches 47 to 61. The second contacts of said switches are individually connected by suitable wires 47, 49', 51', 53', 55', 57, 59 and 61' to the windings of solenoids 69, 7'1, 73, 75, '77, 79, 81 and .83 while the opposite sides of the windings are connected to the other main 67.

The main 67 is also connected to one side of each of the primary switch 85 and the secondary switch 87 Both of said switches are preferably of the mercury type.

The other. side of switch 85 is connected by line 89 to one. input pole 91 of a reversing switch 93 while the switch87 isconnected by line 95 to the other input pole 97 of the same switch.

The main 65 is connected directly to the motors 99, 101 which drive the pumps 11 and 13 respectively.

Output pole 1030f the reversing switch is connected by line 105 to the other side of motor 99 while output pole 107 of the reversing switch is connected by line 109. to the motor 101.

Thus, with the reversing switch in one position, primary switch 85 will start motor 99 and secondary switch 87 will start motor 101 while if the switch 93 is reversed the primary switch will start motor 101 while the secondary switch will start motor 99.

The purpose of this structure is to distribute the wear between the two motors and pumps. This is necessary because the primary switch is energized each time any pedestal is operated'while the secondary switch will be energized only after a predetermined number of pedestals are operated jointly. Since the primary switch will be actuated more often than the secondary by reason of this fact, it follows that if the pumps were not alternately hooked to number one switch, say every other week;

In some cases it may be desired 45 which is designed with larger pipe, hose, etc. so that a larger fiow rate is attained through the unit than through aregular pedestal. In case such a unit is operated from the same pump with a regular pedestal, the

latter might be starved.

To avoid this situation, the switch 63 of the pedestal 45 may be connected in parallel with the secondary I switch 87 by lines 179, 181 so thatone or theother of the motors 99, 101 may be started at once, depending upon the setting of the reversing switch 93. Thereafter,

1 should any pedestal switch 47 to 61 be closed, the other pump will also be energized so that both pumps will be used to supply the two pedestals.

Referring to Figure 7, the internal structure of the i back pressure valves 23, 25 will be'seen to comprise merely a poppet 115 which is urged by a spring 117 2 toward its seat 119. The valve is opened by the flow to restrict the amount of liquid flowing back to the tank while permitting the free escape of any gases.

The control panel The power means preferably in the form of solenoids 69 to 83 effect the operation of the primary and secondary switches 85 and 87 by means of the mechanism shown in Figures 3, and 6.

The solenoids 69 to 83 are all mounted in a row on the panel 127 which is preferably mounted in a cabinet 129.

Each solenoid has an, armature 131 which carries a roller harness 133 in which is mounted a roller 135. A suitable terminal board 30 is provided for connecting the solenoids with the pedestal switches and a similar board 40 is provided for connecting the switches 85 and 87 with the main and the reversing switch 93.

The rollers 135 are disposed below and preferably in substantially tangential contact with the lower side of a thin, fiat tape 137. A series of fulcrums or rollers 139 are rotatably fixed to the panel 127, above and preferably in tangential contact with the upper surface of the tape. The latter rollers are also preferably equidistantly spaced from each other and from rollers 135.

The tape 137 is fixed at one end to a headed anchor 141 which is supported in an ear 143 formed on the panel. The other end of the tape is fixed to a plunger rod 145 which is guided in a yoke 147. The rod carries a collar 149 and a spring 151 confined between the collar and one end of the yoke which serves to urge the rod in a direction to tension the tape.

The lower portion of the rod is threaded as at 153 and adjustably carries a cam nut 155 and a lock nut 157. Pivotally mounted at 159 on the panel and adjacent the cam nut is a lever 161 which has arms 163 arranged to hold a mercury type switch 87 which is the secondary control switch. The lever has a projection 165 which bears on the nut 155 and is held in contact therewith by a spring 167.

For operating the primary switch 85 there is provided a bail 169 which is pivotally mounted at 171 on cars 173 bent from the panel. A hook 175 forms a part of the harness 133 of each solenoid and is engaged beneath the bail. i

A switch holder 177 is connected to one end of the bail and the primary, mercury type switch 85 is mounted thereon so as to be tiltedendwise as the bail pivots. The weight of the bail normally holds the switchin its off or open condition, but as soon as any one of the solenoids to utilize a pedestal harness thereof will raise the bail and hold it raised to hold switch 85 in its on or closed condition.

The nut 155 previously dlescribed is set so that it normally holds the switch 87 in the ofi or open condition. As the plunger 145 is drawn down by the operation of a solenoid, due to the shortening of the tape, the switch will move toward its on or closed condition. However, the first actuated solenoid does not provide suflicient movement to effect closing. Similarly, depending upon the setting of nut 155, the second actuated solenoid also does not close the switch. Preferably, the switch 87 is closed only if three of the solenoids are held energized. If desired, the nut 155 may be set so that four or more solenoids would have to be held energized to close the switch 87, all in accordance with the requirements of the system and the capacity of the pumps employed.

The pedestal 45 has its switch 63 connected by wires 179 and 181 to the neutral 65 and to the line 95 so that it is directly paralleled with the secondary switch 87. Thus, whichever motor 99 or 101 is connected by reversing switch 93 for control by secondary switch 87 will be energized upon closure of switch 63 in the high-speed pedestal.

- Operation The operation of any one of the switches 47 to 61 will energize the corresponding solenoid 69 to 83. Assume that pedestal is to be used to fill a vehicle tank. Switch 53 will close the circuit from the neutral main 65, through switch 53, line 53', solenoid 75 to main 67.

The solenoid is energized and its roller 135 is drawn up with the harness 133 to place a bight in the tape 137 to shorten its effective length and draw the plunger 145 and nut 155 downwardly. This action permits the secondary switch 87 to be tilted slightly, but not enough to close.

The raising of the harness 133 also raises hook 175 and bail 169. This action tilts the primary switch far enough to close it. If we assume that the selector switch is set so that pump 11 and motor 99 are to start first, it will be seen that switch 35 closes a circuit from the hot main 67 through switch 85, terminals 91, 103, line 105, motor 99 to the neutral main 65 so that the motor 99 and pump 11 are started and held in operation.

Suppose that the nut 155 is set so that it will cause switch 87 to close when the third pedestal is operated. When a second pedestal, say 29, is operated and its switch 47 is closed, the solenoid 69 will be energized and its roller will place a second bight in the tape 137 shortening its effective length and pull plunger down farther, but not far enough to close switch 87.

Since the bail 169 is already raised and switch 85 is closed, the energization of the solenoid has no effect on this structure.

Whenthe third pedestal, say 41, is operated with the preceding two held operated, its solenoid81 will be energized. The solenoid cannot afiect switch 85 for the reasons described above but when its roller places a further bight in the tape 137, the plunger 145 and nut are drawn down far enough so that spring 167 will, in tilting the switch 87 to follow the nut 155, close the switch.

It will be seen from Figure 4 that switch 87 closes the remaining circuit from hot main 67 through switch 87, terminals 97, 107 of the reversing switch, line 189, motor 101 to neutral main 65. Pump 13 will therefore be started and will be held in operation so long as all three pedestals are being used, but as soon as any one of the pedestal switches is opened and no additional pedestal switches are closed, the last started pump 13 and motor 101 will be stopped. It is obvious that regardless of which of the pedestals 29 to 43 is started, the pump 11 will be started and that regardless of which pedestal is the third one to be placed in service, it will start the second pump 13.

The reversing switch merely changes the above described circuits so that when primary switch 85 is closed it will close the circuit 67, S5, 91, 107, 109, 101 to 65 to start the pump 13 while the secondary switch closes the circuit 67, 87, 95, 97, 3, 105, 99 to 65 to start the pump 11.

The switch 63 of the high-speed or truck servnig pedestal 45 is connected in parallel with the secondary switch 87 so that at any time this pedestal i used, it will start the pump which is being controlled by the secondary switch S7 regardless of whether the pump controlled by switch S5 is operating or not.

Thus, if no pump is running and switch 93 is set to connect switch 35 with motor Q5 and switch S7 with motor 1.01, closure of switch (:3 will start motor 101. If any of the other switches 29 to 43 is subsequently closed, it will immediately bring in motor 99. If switch 2'37 is subsequently closed it will be ineffective since motor 101 is already operating, unles pedestal 45 is shut down, in which case switch 87 will hold motor 101 energized.

Thus, a good supply of liquid is assured when the highspeed pedestal and a regular pedestal are being used simultaneously or when more than a predetermined number of regular pedestals are in use. The action is positive in that the energization of the pumps is totally independent of the conditions which effect the flow of fluid in the lines. Thus, the system is not subject to hunting which is a defect of pressure or flow responsive controls. Neither need it be adjusted to the particular flow, pressure, friction, etc. conditions of the system in which it operates as do systems which are responsive to pressure or flow conditions.

Further, the entire solenoid and switch system, except the pedestal switches can be mounted in the station building at a point remote from all of the gasoline handling means so that it need not be of vapor proof construction. This greatly reduces the cost or" such installations.

Modified form Referring to Figures 8, 9 and 10, a modified form of control mechanism is shown which is hydraulic.

The solenoids 6%, 71', 73', 75', 77, '79, 81' and 83' are connected in the system in the same manner as the solenoids 59 to 83 described above. Each armature 2G1 is connected to the end or" a lever 203 which has its other end pivotally mounted at 205 on a back plate 297, as shown in Figure 10. Each lever carries a screw 2139 which is held in place by a nut 211 and which presses on the end of a bellows 213 which is suitably supported by the yolzes 2E5, 23.7 and guide block 219 secured to the back plate.

Each bellows, and there is one for each solenoid, is connected by a tube 221 in communication with a manifold 223 which is supported on the plate 207 by clips 225.

A master bellows 227 is connected in communication with the manifold by a tube 229 at one end and with a reservoir 231 at the other end.

A bracket 233 mounted on the plate supports the reservoir. A cap 235, which is vented at 237, covers the reservoir and slidably guides the needle valve 239 which controls the orifice 241 of the tube 243 which connects the bellows 227 and the reservoir.

A plunger rod 245 is guided in a bearing 247 also fastened to the plate 2%? and has a spring seat 249 fixed to its lower end to retain the spring 251 which rests upon a flange 253 formed on the reservoir.

The plunger rod is provided with a bore lower end into which the upper end of the press fitted and a flange 257 on the valve end of the rod.

A spring 259 is confined between the bearing 247 and the seat 249. This spring is more rigid than spring 251 so that the latter will yield when bellows 227 expands.

Stop nuts 261 are threaded on the upper end of the rod and engage the bearing 247 to limit downward travel 6 of the rod and a switch actuator collar 263 is adjustably fixed to the upper end of the rod.

As shown in Figure 8, an arm 265 is fixed to the flange 253 and is adapted to bear down on the actuating lever of a self closing primary switch to hold the switch open.

Similarly, an actuator 269 of a secondary switch 87 which is positioned for operation by the collar 263 and which is normally open and is closed by the collar. Numeral 93' indicates the reversing switch.

Bracket supports a depending tube 234 which partially encloses the bellows 227 to guide it and prevent it from being damaged.

Operation The primary switch 35, secondary switch S7 and re versing switch 36 are connected in the circuit shown in Figure 4 in the same manner as the switches 85, 87 and 93 described above.

Attention is first directed to the fact that spring 259 holds the plunger 245 in its downward position which is determined by the contact of the stop nuts 261 with bracket 247. The spring 251 urges the reservoir 231 and bellows 227 downwardly so that the reservoir will rest on the bracket 233. When the rod and reservoir are thus located, the valve 239 is off the seat 241, preferably about .005 inch, so that fluid can flow between the reservoir and the bellows.

Thus any gas entrapped in the system can escape and liquid can move into or outof the system as the temper ature varies.

However, as soon as any pedestal switch is closed, a solenoid 69" to 3-3 is energized and its corresponding bellows 213 is compressed. The liquid expelled from the bellows is transmitted through the manifold to the bellows 227 to elongate it and to raise the reservoir 231 until the seat 241 contacts valve 239. The spring 251 is compressed suiliciently to permit this action.

The liquid system is now sealed and further motion lifts the rod 245. The operation of a second pedestal switch results in a further extension of the bellows 227 and so on.

The first movement of the bellows 227 raises the arm 265 from the actuator of switch 85 so that it will close and start the first pump. Usually the switch 87 is so set that the third expansion of the bellows 227 will cause the collar 263 to move the switch actuator 26? far enough to close switch 87 so that the second pump is started.

The switches 85', 87' are opened in the reverse order as pedestal switches are opened.

It will be seen that this structure will have the same advantages and will perform the same functions as the preferred form.

It is obvious that various changes may be made in the form, structure and arrangement of parts without de parting from the spirit of the invention. Accordingly, applicants do not desire to be limited to the specific embodiment disclosed herein primarily for purposes of illustration; but instead, they desire protection falling fairly within the scope of the appended claims.

What we claim to be new and desire to Letters Patent of the United States is:

1. In a control system, the combination of a primary switch, a secondary switch, a number of selectively operable control switches, a number of control device actuated means each connected for energization by a control switch, means responsive to the energization of any control device actuated means for closing said primary switch and means responsive to the subsequent energization of a predetermined additional number of said control device actuated means for closing said secondary switch.

2. In a control system, the combination of a primary switch, a secondary switch, a number of selectively operable control switches, a number of control device actuated means each connected for operation by a control switch,

protect by means responsive to the energization of any control device actuated means for closing said primary switch, means responsive to the subsequent energization of a predetermined additional number of said control device actuated means for closing said secondary switch, a primary motor, a secondary motor, and a reversing switch connected between said primary and secondary switches and said motors for selectively connecting said motors for operation by said primary and secondary switches.

, 3. In a control system, the combination of a primary control means, a secondary control means, a number of selectively operable control devices, a number of control device actuated means each connected for operation by a control device, means responsive to the operation of any control device actuated means for actuating said primary .control means, means responsive to the subsequent operation of a predetermined additional number of said control device actuated means for actuating said secondary control means, a prime mover connected to be controlled by said primary control means, 'an additional prime mover connected to be controlled by said secondary control means, another selectively operable control device and means for connecting it directly to control said additional 'prime mover.

4. In a control system, the combination of a primary control means, a secondary control means, a number of selectively operable control devices, a number of control device actuated means each connected for operation by a control device, means responsive to the operation of any control device actuated means for actuating said primary control means, means responsive to the subsequent operation of a predetermined additional number of said control device actuated means for actuating said secondary control means, a primary motor, a secondary motor, and a reversing mechanism connected to selectively place said primary and secondary motors under the control of said primary or secondary control means.

5. In a control system, the combination of a primary switch, a secondary switch, a number of selectively operable control switches, a number of solenoids each connected for operation by a control switch, means responsive to the energization of any solenoid for closing said primary switch, means responsive to the subsequent energization of a predetermined additional number of said solenoids for closing said secondary switch, a primary motor, a secondary motor, and means connecting said primary and secondary motors to said primary and secondary switches respectively.

6. In a control system, the combination of 'a primary switch, a secondary switch, ,a number of selectively operable control switches, a number of solenoids each connected for operation by a control switch, means responsive to the energization of any solenoid for closing said primary switch, means responsive to the subsequent energization of a predetermined additional number of said solenoids for closing said secondary switch, a primary motor, a secondary motor, and means connecting said primary and secondary motors to said primary and secondary switches respectively, and a reversing switch connected between said primary and secondary motors and primary and secondary switches for selectively reversing said connecting means.

7. In a control system, the combination of a primary switch, a secondary switch, a series of selectively operable control switches, control device actuated means connected for energization by each of said control switches, switch actuating means operable by any said control device actuated means for movement progressively through a series of stations, means operable by saidswitch actuating means when it reaches one station for actuating said primary switch and when it reaches a second station for actuating said secondary switch. 7

8. In a control system, the combination of a switch, anumber of selectively operable control switches, a number of solenoids each having a movable armature and c: each connected for operation by a control switch, a flexible member operatively connected to the armatures so that movement of each armature will create a longitudinal movement of said member, means for connecting said member to actuate said switch, and means for relatively adjusting the switch and connecting means to vary the amount of movement of said flexible member required to close the switch.

9. In a control system, the combination of a primary switch, a secondary switch, a number of selectively operable control switches, a number of solenoids each having a movable armature and each connected for operation by a control switch, a bail adapted to be actuated by the energization of any solenoid for closing said primary switch, a flexible member operatively connected to the armatures so that movement of each armature will create a longitudinal movement of said member, and means for connecting said member to actuate said secondary switch.

10. In a control system, the combination of a primary switch, a secondary switch, a number of selectively operable control switches, a number of solenoids each hav- 'ing a movable armature and each connected for operation by a control switch, means including a bail adapted for actuation by any of the solenoids for closing said primary switch, a flexible member operatively connected to the armatures so that movement of each armature will create a longitudinal movement of said member, means for connecting said member to actuate said secondary switch, a primary motor, a secondary motor and means for connecting each of said'motors to one of said primary or secondary switches.

11. In a control system, the combination of a normally open switch, a displaceable actuating means therefor, a number of selectively operable control switches, a

number of control device actuated means each connected for operation by a control switch and including a member displaceable a predetermined distance upon operation of the control device actuated means and means connecting said members to displace said actuating means in proportion to the sum of the displacement of the displaced members.

12. In a control system, the combination of a normally open switch, a displaceable actuating means therefor, a number of selectively operable control switches, a number of control device actuated means each connected for operation by a control switch and including a member displaceable a predetermined distance upon operation of the control device actuated means, means connecting said members to displace said actuating means in proportion to the sum of the displacement of the displaced members, said actuating means being effective to close said switch when said displacement of said actuating means is the equivalent of a predetermined multiple of the displacement efiected by one member.

13. In a control system, the combination of a switch movable from open to closed position, a number of fulcrums, a member mounted for movement to close and open said switch, a tape connected to said member at one end, extending past and in contact with said fulcrums and fixed at its other end, a series of solenoids having movable armatures, tape actuating means supported by each armature and disposed in contact with the tape on the side opposite the fulcrums when the solenoid is deenergized, said tape actuating means being interposed between adjacent fulcrums, a series of control switches, one for each solenoid, so that upon energization of the solenoids, the tape actuating means will introduce a bight in the tape, and means connecting each switch to energize or deenergize its solenoid.

14. In a control system, the combination of a switch movable from open to closed position, a number of fulcrums, a member mounted for movement to close and open said switch, a tape connected to said member at one end, extending past and in contact with said fulcrums and fixed at its other end, a series of solenoids having movable armatures, tape actuating means supported by each armature and disposed in contact with the tape on the side opposite the fulcrums when the solenoid is deenergized, said tape actuating means being interposed betweenadjacent fulcrums so that upon energization of the solenoids, the tape actuating means will introduce a bight in the tape, a series of control switches, one for each solenoid, and means connecting each switch to energize or deenergize its solenoid, means on said member for adjusting the position of the switch relative to said member to alter the amount of movement of the tape required to close the switch.

15. In a control system, the combination of a switch movable from open to closed position, a number of fulcrums, a member mounted for movement to close and open said switch, a tape connected to said member at one end, extending past and in contact with said fnlcrums and fixed at its other end, a series of solenoids having movable armatures, tape actuating means supported by each armature and disposed in contact with the tape on the side opposite the fulcrums when the solenoid is deenergized, said tape actuating means being interposed between adjacent fulcrums so that upon energization of the solenoids, the tape actuating means will introduce a bight in the tape, a series of control switches, one for each solenoid, and means connecting each switch to energize or deenergize its solenoid, a member mounted for movement relative to all of said armatures and disposed for movement by any of them and a normally open switch connected to be closed by said member upon movement thereof by an armature.

16. In a control system, the combination of a normally open switch, a displaceable actuating means therefor, a number of selectively operable control switches, a number of control device actuated means each connected for operation by a control switch and including an hydraulic member displaceable a predetermined distance upon operation of the control device actuated means, and hydraulic means connected with said hydraulic members to displace said actuating means in proportion to the sum of the displacement of said members.

17. In a control system, the combination of a normally open switch, an hydraulic motor including displaceable switch actuating means connected thereto, a number of selectively operable control switches, a number of control device actuated means each connected for operation by a control switch and including an hydraulic bellows displaceable a predetermined distance upon operation of the control device actuated means, means connecting said bellows to displace said hydraulic motor and said actuating means in proportion to the sum of the displacement of said displaced bellows, said actuating means being effective to close said switch when said displacement is the equivalent of a predetermined multiple of the displacement effected by one bellows.

18. In a control system, the combination of a normally open switch, an hydraulic motor including displaceable switch actuating means connected thereto, a number of selectively operable control switches, a number of control device actuated means each connected for operation by a control switch and including an hydraulic bellows displaceable a predetermined distance upon operation of the control device actuated means, means connecting said bellows to displace said hydraulic motor and said actuating means in proportion to the sum of the displacement of said displaced bellows, said actuating means being effective to close said switch when its displacement is the equivalent of a predetermined multiple of the displacement eflected by one bellows, a reservoir mounted on the upper end of said hydraulic motor and communieating therewith through a port having a valve seat, a valve connected with said switch actuating means and movable therewith relative to said seat, first yieldable means holding said valve away from said seat, second yieldable means for urging said valve toward said seat, stop means for limiting the movement of said valve toward the seat, said first yieldable means being weaker than the second so that the initial movement of said reservoir will move the seat into contact with the valve to seal the hydraulic means.

References Cited in the file of this patent UNITED STATES PATENTS 578,673 Boetcher Mar. 9, 1897 668,978 Carlson Feb. 26, 1901 1,540,741 Hunter June 2, 1925 1,672,690 Runner June 5, 1928 2,042,169 Cook May 26, 1936 2,129,526 Crago Sept. 6, 1938 2,482,496 McGilliuray Sept. 20, 1949

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