US3460591A

US3460591A - Fluid filling method and apparatus

Info

Publication number: US3460591A
Application number: US659774A
Authority: US
Inventors: Arthur A Chalenski Jr; Walton Hughes
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1967-08-10
Filing date: 1967-08-10
Publication date: 1969-08-12
Anticipated expiration: 1986-08-12

Description

Aug.12,1969 A.A.CHALENSKI, JR.. ETAL 3,460,591

FLUID FILLING METHOD AND APPARATUS Filed Aug. 10. 1967 2 Sheets-$heet 1 VAC. 1 5w.

M/mr A. [Mans/ 4. x 5 ya/iozz hes ATTORNEY Aug. 12, 1969 L 5K JR, ET AL 3,460,591

FLUID FILLING METHOD AND APPARATUS Filed Aug. 10. 1967 2 Sheets-Sheet 2 Z02 z, l

ATTORNEY United States Patent FLUID FILLING METHOD AND APPARATUS Arthur A. Chalenski, .lr., Garwood, and Walton Hughes,

Scotch Plains, N.J., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Aug. 10, 1967, Ser. No. 659,774 Int. Cl. B651) 31/02; 1367c 3/02 US. Cl. 1417 13 Claims ABSTRACT OF THE DISCLOSURE Filling a fluid system to a desired level where the system contains varying amounts of liquid precluding the possibility of filling with a premeasured volume of liquid. The filling cycle comprises an evacuating phase in which the system to be filled is evacuated of almost all the air therein leaving a small percentage of the original air remaining. The liquid for the system is then delivered thereto under pressure to overfill the system and build up a superatmospheric pressure so that the remaining air is compressed to a fraction of its normal volume. The excess liquid is then removed in a blowback phase while the system is maintained under pressure. At the end of the blowback phase the correct volume of liquid is trapped in the system and the excess air pressure is vented to the atmosphere to complete the filling cycle.

This invention relates to a method and apparatus for filling a fluid system and more particularly to such a method and apparatus employing a filling cycle having an evacuating phase, a pressurized overfilling phase, a blowback phase to remove excess fluid While the system is maintained under pressure and a terminating venting phase.

There are several diflicult problems found in rapidly filling fluid systems already having varying amounts of liquid which preclude the possibility of filling with a premeasured volume of liquid. For example, an automotive power steering system can be filled by adding oil to the power steering pump reservoir, starting the engine, turning the steering wheel lock to lock several times and then topping off the reservoir with additional oil. In order that the correct level be established, thorough purging of the air from the steering cylinder of the power steering system is required consuming considerable operator time. If the topping oil operation is performed while the system is running and the system is not sufliciently purged of air, the oil may overflow when the engine is shut of resulting in oil spillage and an incorrect oil level.

The present invention is particularly well suited for filling fluid systems such as an automotive power steering system and is especially useful on a production basis on an automobile assembly line as will be demonstrated. Apparatus for carrying out the method of the present invention comprises hydraulic and penumatic fluid circuits automatically controlled according to a timed sequence by an electrical circuit to provide a filling cycle having an evacuating phase, a filling phase, a blowback phase, and a venting phase. The filling cycle starts with evacuation of air from the power steering system in the evacuating phase. A small percentage of the total air remains in the power steering system at the end of the evacuating phase and in the next phase which is the filling phase, power steering oil is delivered under pressure to fill the steering system and build up a superatmospheric pressure therein. The remaining air is compressed to a fraction of its normal volume at the end of the filling phase. The excess oil is then removed in the blowback phase while the power steering system is maintained under 3,460,591 Patented Aug. 12, 1969 pressure. At the end of the blowback phase the correct volume of oil is trapped in the steering system which is then vented in the terminating venting phase whereafter the operator can disconnect the filling apparatus from the power steering system.

An object of the present invention is to provide a fluid filling method and apparatus employing an evacuating phase, a pressurized overfilling phase, an excess fluid removal phase while pressure is maintained and a terminating venting phase.

Another object is to provide a fluid filling method and apparatus for automatically filling a fluid system, where complete air evacuation of the system will consume considerable time and the system already has varying amounts of liquid, by evacuating the system so that a small percentage of the original air remains, filling the system with liquid under superatmospheric pressure so that the remaining air in the system is compressed and a fluid overfull condition is achieved, withdrawing the excess fluid while the superatmospherie pressure is maintained in the system and equalizing the system pressure with atmospheric pressure.

Another object is to provide a fluid filling method and apparatus for automatically filling an automotive power steering system by evacuating the system so that a small percentage of the original air remains, delivering power steering oil under superatmospheric pressure to completely fill the steering system and develop a. superatmospheric pressure so that the remaining air is compressed to a fraction of its normal volume, removing the excess oil from the system by a superatmospheric air pressure which maintains the system under pressure and trapping the correct volume of oil in the steering system and venting the system air pressure to the atmosphere prior to disconnecting the apparatus from the power steering system.

These and other objects of the present invention will be more apparent from the following description and drawing in which:

FIGURE 1 schematically illustrates hydraulic and pneumatic apparatus for carrying out the filling process of the present invention.

FIGURE 2 schematically illustrates electrical circuitry for automatically controlling the hydraulic and pneumatic apparatus shown in FIGURE 1.

The present invention is demonstrated for use on a final assembly line in filling automotive power steering systems having two different fluid reservoir fill neck configurations and correct liquid levels. The filling apparatus is provided as shown in FIGURE 1 with two diflerent size fill heads 10 and 12 to establish the proper connection between the filling apparatus and the inlet of the system to be filled. In the power steering systems which are generally designated as 14 and 16 the inlet connection is at the power steering

pump fill necks

18 and 20, respectively.

The apparatus further comprises a tank 22 which is fed with power steering oil from any suitable source via a line 24 in which there is provided a float valve 26. The float 25 of valve 26 responds to the liquid level in tank 22 to control the opening and closing of valve 26 so that tank 22 is maintained substantially full at all times as shown. The tank is vented to atmosphere by a vent 28 to prevent pressure build up in the tank during operation.

Oil pressure supply to the fill heads is provided by the portion of the hydraulic circuit which has an electric motor 30 connected to drive an oil pressure pump 32 preferably of the positive displacement type. Pump 32 is connected in an oil pressure line 34 connecting the tank 22 to an oil fill hose 36. Pump 32 receives oil from the tank at its suction side and delivers the oil under pressure at its discharge side to oil fill hose 36, there being provided a filter 38 to filter the pressurized oil prior to its delivery to hose 36. Fill pressure in hose 36 is limited by a pressure relief valve 40 which opens at a predetermined pressure to exhaust hose 36 to the tank. The oil fill hose 36 is also connectable by a bypass line 42 to the tank 22, there being provided in line 42 a solenoid valve 44 for controlling the connection. Valve 44 is spring biased to the open position shown when its solenoid is deenergized and moved to its closed position when its solenoid is energized.

The oil fill hose 36 is connected at its other end to a multipurpose hose 46 with the delivery of oil thereto being controlled by a solenoid valve 48. Valve 48 is spring biased to the closed position shown when its solenoid is deenergized and is moved to its open position when its solenoid is energized. The multipurpose hose 46 is connected by

hoses

50 and 52 to the fill heads and 12, respectively. In the fill heads 10 and 12 there are provided passages 54 and 56 which are connected to the

hoses

50 and 52, respectively. The fill head passages are provided in part by bores extending from the ends 58 and 60 of the fill head snouts or probes 62 and 64, respectively, the snouts projecting into the respective power steering pump fill necks.

Foot valves

66 and 68 in the fill heads 10 and 12, respectively, are operable to open and close the passages 54 and 56, respectively, at the respective snout ends. The

foot valves

66 and 68 are operated by

pneumatic motors

70 and 72, respectively, mounted on the respective fill heads.

The air motor 70 of fill head 10 comprises a piston 74 connected to foot valve 66. Piston 74 is exposed to an upper chamber connected to a pneumatic hose 76 and a lower chamber connected to a pneumatic hose 78. When hose 76 is supplied with air pressure and hose 78 is exhausted, the foot valve 66 opens to connect passage 54 and connected hose 50 to the power steering system. Alternatively, when hose 78 is pressurized and hose 76 is exhausted foot valve 66 is moved by the air pressure to the closed position shown to disconnect hose 50 and the power steering system. A solenoid valve 80 controls the operation of pneumatic motor 70 and thus foot valve 66. Valve 80 is spring biased to the position shown when its solenoid is deenergized to connect hose 78 to an air pressure hose 82 while connecting hose 76 to the atmosphere. Air pressure hose 82 is supplied with a regulated air pressure in any suitable manner and with valve 80 in its spring biased position, foot valve 66 is closed as shown. When the solenoid of valve 80 is energized, hose 78 is exhausted and hose 76 is pressurized via valve 80 to move the foot valve 66 to its open position.

The pneumatic motor 72 operating the foot valve 68 in fill head 12 is similarly controlled by a solenoid valve 84. Valve 84 is spring biased to the position shown when its solenoid is deenergized to connect the lower piston chamber via a hose 86 to the air pressure hose 82 while connecting the upper piston chamber via a hose 88 to the atmosphere whereby footvalve 68 is moved by piston 90 to the closed position shown. When the solenoid of valve 84 is energized, hose 86 is exhausted to the atmosphere and the hose 88 is pressurized via valve 84 to move foot valve 68 to its open position.

In the vacuum portion of the filling apparatus an electric motor 92 is connected to drive a vacuum pump 94 which is preferably of the aspirating type and requires a supply of fluid to actuate the jet to establish a vacuum in vacuum hose 96 and also cool the pump. The fluid for such action is provided by the oil in tank 22 which communicates with the vacuum pump via a line 98. The oil supplied to the vacuum pump 94 by line 98 and any oil which is pulled back through hose 96 as described in detail later is returned via a return line 100 to the top of the tank. Hose 96 is connected at its other end to the multipurpose hose 46 at the junction of fill hose 36. In hose 96 there is provided a solenoid valve 102 which is spring biased to the closed position shown when its 6 solenoid is deenergized and moved to its open position when its solenoid is energized to establish the vacuum connection.

In a blowback and purge portion of the apparatus there is provided a hose 104 which is connected to multipurpose hose 46 at its juncture with fill hose 36 and vacuum hose 96. In hose 104 there is provided a solenoid valve 106 which is spring biased to the closed position shown when its solenoid is deenergized. Valve 106 is moved to its open position when its solenoid is energized to establish connection to a pressure relief valve 108. Relief valve 108 exhausts to a receiver 110 connectable via a hose 112 to the vacuum hose 96 between valve 102 and the vacuum pump 94 and close to valve 102. A solenoid valve 114 in hose 112 is spring biased to the closed position shown when its solenoid is deenergized and moved to its open position when its solenoid is energized.

Venting of and also blowback of excess oil from the power steering system is via passages 116 and 118 extending through the fill heads 10 and 12, respectively. The through passages 116 and 118 are exposed to the respective power steering systems at the top of the fill neck and connected to hoses 120 and 122, respectively. Referring to fill head 10 and the vent, blowback hose 120, this hose is connectable to either the atmosphere for venting or to an air pressure hose 124. Air pressure hose 124 is connected to receive air from the main air pressure hose 82 via a pressure regulator valve 126 which regulates the pressure in hose 124 at an adjustable value. A solenoid valve 128 controls the venting and is spring biased to the closed position shown when it solenoid is deenergized and moved to its open position connecting hose 120 to atmosphere when its solenoid is energized. A solenoid valve 130 controls the 'blowback connection and is spring biased to the closed position shown when its solenoid is deenergized and moved to its open position when its solenoid is energized. The vent, blowback hose 122 for fill head 12 is similarly connected to the atmosphere and the air pressure hose 124 by

solenoid valves

132 and 134, respectively.

The hydraulic and pneumatic apparatus described above is automatically controlled according to a predetermined timed sequence by the electrical circuit shown in FIG- URE 2. In the following description the same numeral is used to identify a relay coil and the one or more contacts it controls but with the contact identifying numeral primed.

The electrical circuit has three

input terminals

200, 202 and 204 for connection to a suitable three-phase power source. The three-phase motor 92 powering the vacuum pump 94 is connected to the

input terminals

200, 202 and 204 by means of

lines

206, 208 and 210, respectively, and a three-pole disconnect switch 212. Normally open,

relay contacts

214', 214 and 214" are provided in

lines

206, 208 and 210, respectively, and thermo-

overload elements

216 and 218 are also provided in

lines

206 and 210, respectively. The three-phase motor 30 which powers the pressure pump 32 is connected in parallel with the vacuume pump motor by means of

lines

220, 222 and 224 which are connected to

lines

206, 208 and 210, respectively, at points intermediate the disconnect switch 212 and the vacuum pump motor relay contacts. Normally open,

relay contacts

226, 226 and 226' are provided in

lines

220, 222 and 224, respectively, and thermo-

overload elements

228 and 230 are also provided in lines 220 and 224, respectively.

The control circuit for the electric motors and the solenoid valves is generally designated at 232 and has an input, stepdown transformer 234. The primary winding terminals of control transformer 234 are connected to the

input terminals

200 and 204 by means of

lines

236 and 238 which are connected to

lines

206 and 210, respectively, at points intermediate the disconnect switch 212 and the motors relay contacts. The terminals of the secondary Winding of transformer 234 are connected to

lines

240 and 242.

The circuit 244 starts and stops the vacuum pump motor 92 and comprises a pushbutton switch 246 which maintains contact, a normally open, relay contact 248' and a relay coil 214 which controls the vacuum pump motor relay contact 214', 214" and 214'. The switch 246, contact 248' and coil 214 are connected in series across

lines

240 and 242 in the manner shown.

The circuit 250 starts and stops the pressure pump motor 30 and comprises a pushbutton switch 252 which maintains contact, a normally open, relay contact 254' and a relay coil 226 which controls the pressure pump motor relay contacts 226', 226" and 226". Switch 252, contact 254' and coil 226 are connected in series across

lines

240 and 242 in the manner shown.

The circuit 256 controls the vacuum pump motor circuit 244 and comprises normally closed,

relay contacts

216 and 218 controlled by the vacuum pump motors overload

elements

216 and 218, respectively, and a relay coil 248 which controls the contact 248' in circuit 244. The contacts 216' and 218 and the coil 248 are connected in series across

lines

240 and 242 in the manner shown.

The circuit 258 indicates whether or not the vacuum pump motor 92 is operating. The circuit comprises a normally closed, relay contact 248" controlled by coil 248 in circuit 256 and a press-to-test light 260,

elements

248 and 260 being connected across

lines

240 and 242 in the manner shown.

The circuit 262 controls the pressure pump motor circuit 250 and comprises normally closed, relay contacts 228' and 230 which are controlled by the pressure pump motors overload

elements

228 and 230, respectively, and a relay coil 254 which controls the relay contact 254. Contacts 228 and 230' and coil 254 are connected in series across

lines

240 and 242 in the manner shown.

The circuit 264 indicates whether or not the pressure pump motor 30 is operating. The circuit comprises a normally closed, relay contact 254" controlled by coil 254 in circuit 262 and a press-to-test light 266, elements 254" and 266 being connected across

lines

240 and 242 in the manner shown.

The circuit 268 starts and stops the filling cycle when either the fill head or fill head 12 is being used and comprises a normally open, pushbutton, operator-start switch 270 for use with fill head 10, a normally open, pushbutton, operator-start switch 272 for use with fill head 12 and a normally closed, pushbutton, operatorstop switch 274 for use with both fill heads 10 and 12. Circuit 268 further comprises a normally open, relay contact 248" controlled by coil 248 in circuit 256 and a normally open, relay contact 254" controlled by coil 254 in circuit 262. There is also provided three normally closed, relay contacts 275', 27-6' and 280, a normally open, relay contact 276", a pair of press-to-test lights 284 and 286 and a relay coil 276 which controls contacts 276' and 276". Circuit 268 further comprises a master cycle timer 288 having a single phase motor 290 which is connected by a solenoid operated clutch 292 upon clutch solenoid energization to drive cams which operate timer contacts as described in greater detail later.

In circuit 268 the

switches

270 and 274, contacts 248', 254" and 275 and the timer motor 290 are connected in series across

lines

240 and 242 in the manner shown. The timer solenoid clutch 292 is connected in parallel with contact 275 and the timer motor 290. Contact 276' and light 284 are connected in parallel with contact 275 and the timer motor with the light 284 also connected to line 240 in the manner shown. The switch 272, contact 280' and coil 276 are connected in series across

lines

240 and 242 in the manner shown. The light 286 is connected in parallel with coil 276 and also to line 240 in the manner shown. The contact 276" is connected in the circuit 268 across the line connecting :

switches

270 and 274 and the line connecting contact 280' and coil 276.

The timer circuit 294 times the operation of both the

vent control valves

128 and 132 and comprises a normally open, contact 296 whose opening and closing is controlled by a timer cam 298 of the master cycle timer 288, a relay coil 280 which controls contact 280 in circuit 268, a normally closed, relay contact 300, the solenoid 302 of the vent valve 128, the solenoid 304 of the vent valve 132, a normally open, pushbutton, jog-vent switch 306 and an indicating light 308. The timer contact 296 is for connecting line 240 by means of the contact 276" to the relay coil 276 in circuit 268 in the manner shown and is also for connecting the line 240 to a line 310. Coil 280 is connected across

lines

310 and 242. Line 310 is connected by means of the contact 300 to the

solenoids

302 and 304 and the light 308 which are connected in parallel to line 242. The jog-vent switch 306 is for connecting the line 240 directly to the

solenoids

302 and 304 and the indicating light 308.

The timer circuit 312 is a follower circuit for interrupting the power to the

vent valves

128 and 132 and completing the power circuit to the solenoid valves and 84 controlling the fill

head foot valves

66 and 68, respectively. The circuit 312 comprises a normally open, timer contact 314 whose opening and closing is controlled by another cam 316 of the master cycle timer 288 and a relay coil 300 which controls the contact 300 in circuit 294. Contact 314 and coil 300 are connected in series across

lines

240 and 242.

The circuit 318 controls the opening and closing of the fill

head foot valves

66 and 68 and comprises a normally open, relay contact 300" controlled by coil 300 in circuit 312, a normally closed, relay contact 276" and a normally open, relay contact 276" both of which are controlled by coil 276 in circuit 268, the solenoid 320 of valve 80 and the solenoid 322 of valve 84. The circuit 318 further includes normally open, pushbutton, jog-

fill switches

324 and 326 and a pair of indicating lights 328 and 330.

Contacts

300 and 276" and the solenoid 320 are connected in series across

lines

240 and 242 in the manner shown. Light 328 is connected across solenoid 320 and the jog-fill switch 324 is for connecting both the solenoid 320 and light 328 directly to line 240.

Contacts

300 and 276 and the solenoid 322 are connected in series across

lines

248 and 242 with light 330 connected across the solenoid. The jog-fill switch 326 is for connecting the solenoid 322 and light 330 directly to line 240.

The timer circuit 332 is a follower circuit for interrupting the power to the purge valve 114 and completing the power circuit to the vacuum valve 102. Circuit 332 comprises timer contact 334 whose opening and closing is controlled by another timer cam 336 of the master timer 288 and a relay coil 338. Contact 334 and coil 338 are connected in series across

lines

240 and 242.

The circuit 340 controls the operation of the vacuum valve 102 and comprises a normally open, relay contact 338' controlled by coil 338 in circuit .332, the solenoid 342 of valve 102, an indicating light 344 and a normally open, pushbutton, jog-vacuum switch 346. Contact 338' and solenoid 342 are connected in series across

lines

240 and 242. Light 344 is connected across solenoid 342 and switch 346 is for connecting line 240 directly to the solenoid 342 and light 344.

The circuit 348 controls the termination of evacuation of the systems being filled and comprises a vacuum switch 350 whose sensor is connected to the till

head hoses

50 and 52 as shown in FIGURE 1, a relay coil 352 and an indicating light 354. The switch 350 and coil 352 are connected in series across

lines

240 and 242 and the light 354 is connected across the coil.

The timer circuit 356 provides a leak alarm and also controls the operation of the fill valve 48 and the bypass value 44. Circuit 356 comprises a timer contact 358 whose opening and closing is controlled by another timer cam 360 of the master timer 288. Circuit 356 also includes a normally closed, relay contact 352 controlled by coil 352 in circuit 348, normaly open, relay contact 275" and a normaly closed, relay contact 275" both of which are controlled by a relay coil 275 which also controls contact 275 in circuit 294, a bell 364 and a pressto-test light 366. Circuit 356 further includes the solenoid 368 of the fill valve 48, the solenoid 370 of the bypass valve 44, an indicating light 372 and a normally open, pushbutton, jog-fill, bypass switch 374. The contacts 358 and 352' and the coil 275 are connected in series across

lines

240 and 242. The contact 275 is connected across the contact 352' and the bell 364 and light 366 are sepa- -rately connected across the coil 275. The contact 275" and solenoid 368 are connected in series with contact 358 across

lines

240 and 242. The solenoid 370' and indicating light 372 are separately connected across the solenoid 368. The switch 374 is for connecting the solenoids 36S and 370 and the light 372 directly to line 240, all of the above connections being made in the manner shown.

The timer circuit 376 controls the

blowback valves

130 and 134 and the return valve 106. Circuit 376 comprises a timer contact 378 whose opening and closing is controlled by another timer cam 380 of the master timer 288. Circuit 376 further includes a normally closed, relay contact 276" and a normally-open, relay contact 276"" both of which are controlled by the coil 276 in circuit 294, the solenoid 382 of the blowback valve 130 and the solenoid 384 of the blowback valve 134. The circuit 376 further includes indicating

lights

386 and 388, and normally open, pushbutton, jog-blowback switches 390 and 392. Circuit 376 further includes the solenoid 394 of the return valve 106, an indicating light 396 and a normally open, pushbutton, jog-return switch 398. The

contacts

378 and 276 and the solenoid 382 are connected in series across

lines

240 and 242 with light 386 connected across solenoid 382. The switch 390 is for connecting the solenoid 382 and light 386 directly to line 240. Contact 276" and solenoid 384 are connected in series with contact 378 across

lines

240 and 242 with light 388 connected across solenoid 384. Switch 392 is for connecting the solenoid 384 and light 388 directly to line 240. Solenoid 394 is connected in series with contact 378 across lines 240' and 242 with light 396 connected across solenoid 394. Switch 398 is for connecting the solenoid 394 and light 396 directly to line 240.

The circuit 400 controls the purge valve 114 and comprises a normally closed, relay contact 338 controlled by coil 338 in circuit 332, the solenoid 402 of valve 114, an indicating light 404 and a normally open, pushbutton, jog-purge switch 406. Contact 338" and solenoid 402 are connected in series across

lines

240 and 242 with light 404 connected across solenoid 402. Switch 406 is for connecting the solenoid 402 and light 404 directly to line 240.

The apparatus is preferably divided into subassemblies to reduce operator effort and strain on the fluid and electrical lines. For example, the tank 22, pumps 32 and 94-,

motors

30 and 92, and

valves

40, 44 and 26 may be stationary and located close to the final assembly conveyor. The fill heads 10 and 12 may be supported by cables connected to an operator pulled trolley riding an overhead rail on the operator side of the conveyor. The remaining apparatus may be mounted on the trolley.

To illustrate the fluid filling process provided by the combined operation of all the apparatus described above, recourse is made to an actual apparatus constructed in accordance with the present invention in which the following settings were used for filling automotive power steering systems on a final assembly line.

FLUID PRESSURE SETTINGS Components: Settings, psi. Relief valve 40 35 Main air line 82 100 Pressure regulator 126 35 8 PRESSURE SYVITCH SETTINGS Vacuum switch 350: Hg vacuum, in.

NOTE.The bar indicates when the particular timer contact is glgggd and, accordingly, the absence thereof indicates when the contact is Describing now the fluid filling process provided by the hydraulic and pneumatic components in the automatic operating sequence provided by the electrical control circuit with the above settings, the disconnect switch 212 is closed to deliver power to the electrical circuitry. The apparatus is conditioned for a filling operation by presing both the pump motor start switches 246 and 252 as for example at the beginning of an operator shift. The motor relay coils 214 and 226 are thus energized to close the

motor relay contacts

214, 214", 214" and 226', 226", 226" since the contacts 248 and 254' were closed by the energized coils 248 and 254, respectively, when dis connect switch 212 was closed. Power is thus delivered to the

pump motors

92 and 30 to start the vacuum pump 94 and pressure pump 32, respectively.

Prior to each filling cycle the vacuum hose 96 is purged of any oil that might have accumulated therein during a previous cycle. This is accomplished by the energization of solenoid 402 of the purge valve 114 upon the closing of the disconnect switch 212, the purge valve being thereby opened to open the vacuum hose 96 to the atmosphere via hose 112 and receiver so that the operating vacuum pump 94 draws in air to purge the vacuum line. The energized light 404 indicates the purge valve 114 is open.

All of the remaining electrically controlled valves are deenergized prior to a filling cycle and therefore in the positions shown in FIGURE 1. Thus, both of the fill

head foot valves

66 and 68 are closed as shown. All of the oil discharged from the operating pressure pump 32 is returned to tank 22 through the open bypass valve 44 and the apparatus is in readiness to perform a fill cycle.

The penetration of the fill head snout into the system to be filled determines the liquid level which the filling apparatus will automatically establish. The different size fill heads are provided to accommodate the filling apparatus for filling to two different levels and in systems having different size inlet openings. For example, power steering pump fill neck 18 of the power steering system 14 has a smaller inside diameter opening than fill neck 20 of the steering system 16 and also has a correct oil level 410 which is lower in the fill neck 18 than the correct oil level 412 in fill neck 20. The fill head 10 is sized to accommodate the filling apparatus for filling systems like system 14 by having its tongued, clamping ring 414 matched to the conventional slotted lip of fill neck 18 and its cylindrical snout 62 a small enough diameter to leave a sufiicient annular space in the fill neck connecting the fill head vent, blowback port 116 to the power steering system. The snout 62 is made long enough so that its end is located at oil level 410 when'the fill head is attached to the fill neck as shown. The fill head 12 is sized to accommodate the filling apparatus for filling systems like system 16 by having its tongued, clamping ring 416 matched to the conventional slotted lip of fill neck 20 and its cylindrical snout 64 provided with a larger diameter than snout 62 to provide the same annular space in the larger inside diameter fill neck 20 connecting the vent, blowback port 118 to the power steering system. The snout 64 is shorter than snout 62 so that its end is located at the higher oil level 412 when the fill head is attached to the fill neck as shown.

Assuming that an automobile having a power steering system like system 14 is closely approaching the filling apparatus, the operator connects fill head 10 to the fill neck 18 of the approaching system. With the fill head 10 attached, the filling cycle for filling this system using fill head 10 is initiated by the operator pressing the master start switch 270 in circuit 268. In circuit 268, the contacts 248" and 254" have previously been closed by their energized coils 248 and 254, respectively, when the disconnect switch 212 was closed. Thus, power is supplied to the master cycle timer motor 290 and clutch 292 which clutch then clutches all of the

timer cams

298, 316, 336, 360 and 380 to the operating timer motor. The energized clutch solenoid also operates a release bar in the master cycle timer 288 that causes the

timer contacts

296, 314 and 334 in

circuits

294, 312 and 332, respectively, to close, these contacts being adjusted to start at zero time as shown in the cycle chart. With the timer contact 296 closed, the circuit 294 provides a holding circuit until the total cycle time runs out and opens the timer contact 296 at the end of the four phases of the cycle as shown in the cycle chart. The energized light 284 indicates the cycle is started with fill head 10 1n use.

Closing of the timer contact 314 in circuit 312 energizes coil 300 which then opens contact 300 and closes contact 300". Opening of contact 300' prevents energization of

solenoids

302 and 304 so that the

vent valves

128 and 132 do not open when timer contact 296 closes. Closing of contact 300" in circuit 318 delivers power to the solenoid 320 which thus causes the foot valve 66 in fill head 10 to open. The energized light 328 indicates valve 66 is open. Upon closing of the timer contact 334 the coil 338 is energized which then closes contact 338' in circuit 340. Power is thus delivered to solenoid 342 which then opens the vacuum valve 102 to connect the vacuum pump 94 to the power steering system for the evacuating phase. The energized light 344 indicates valve 102 is open. The energized coil 338 also opens contact 338" in circuit 400 to deenergize solenoid 402 so that the purge valve 114 is closed during the evacuating phase. The coil 280 which is energized upon the closing of the timer contact 296 opens contact 280' so that the start switch 272 for the fill head 12 cannot deliver power if it is closed during the cycle using fill head 10.

The master cycle timer continues timing and after a sufiicient time to establish the desired vacuum in the power steering system the evacuating phase is terminated. In an actual assembly line operation the steering gear section of the power steering system will already contain varying amounts of oil and the pump will generally be nearly empty. Complete air evacuation of the power steering system generally cannot be accomplished because of the existing oil and the fact that evacuation of the steering power cylinder must take place through small passages in the power steering control valve. In an actual power steering system, to of the total air remains at 25" Hg vacuum measured at the connection of vacuum switch 350 to the

hoses

50 and 52, which evacuation was sufficient to accomplish the desired filling operation.

As shown in the cycle, only the timer contact 334 opens at the end of a normal air evacuating phase of the cycle (no steering system leakage) and deenergizes coil 338. The length of time of the vacuum phase is sufficient to establish at least 25" Hg vacuum in the power steering system provided there is no leakage. Upon deenergization of coil 338, contact 338' in circuit 340 is opened and thus the solenoid 342 is deenergized to close the vacuum valve 102 to disconnect the vacuum pump from the power steering system. Deenergization of coil 338 also closes contact 338" in circuit 400 to energize the solenoid 402 to open the purge valve 114. The purge valve 114 remains open during the remaining phases of the cycle to purge the vacuum line 96 for the evacuating phase in a succeeding filling cycle.

If the power steering system leaks during the evacuating phase, vacuum switch 350 in circuit 348, which switch provides a vacuum checking operation, will remain open and therefore coil 352 will remain deenergized at the end of the timed evacuating phase. Thus, the contact 352 in circuit 356 controlled by coil 352 will remain closed and the timer contact 358 which closes as shown in the cycle chart to establish the oil filling phase will energize coil 275 which then closes contact 275" so that coil 275 remains energized. Contact 275" is opened by the energized coil 275 to prevent energization of solenoid 368 and thus prevent opening of the oil fill valve 48. The contact 275 in circuit 294 is opened by the energized coil 275 and thus stops the action of the master cycle timer 288. Power is also applied to the bell 364 and light 366 to signal the operator that the power steering system is leaking and that the filling apparatus is locked out so that the operator can take whatever corrective steps are necessary. The bell and light will continue signaling until the stop switch 274 in circuit 268 is opened.

Provided the power steering system did not leak and vacuum builds up, the master cycle timer advances into the filling phase in which the fill valve 48 opens and the bypass valve 44 closes. This is accomplished by the increasing vacuum in the power system closing the vacuum switch 350 at 25" Hg. vacuum. Closing of vacuum switch 350 energizes coil 352 which then opens contact 352' in circuit 356 so that the leak signals are not produced. The closing of timer contact 358 applies power to solenoid 368 of the fill valve 48 which then opens so that oil from the pressure pump 32 is delivered to the power steering system. The solenoid 370 of the bypass control valve 44 is also energized upon the closing of timer contact 358 so that valve 44 is closed and the oil can no longer bypass back to the tank. Energization of light 372 indicates that the fill valve 48 is open and bypass valve 44 is closed. The oil fill phase is terminated by the timer contact 358 opening to close the fill valve 48 and open the bypass valve 44. The filling phase is provided with sufiicient time which is controlled by the timer contact 358 so that the power steering system is filled with oil and the oil pressure builds to 35 p.s.i. whereafter the relief valve 40 prevents further pressure build up. The system is slightly overfilled with the oil level at the top of the fill neck and the remaining air in the system compressed to approximately one-third /3) its normal volume.

In the next phase, which is the blowback pha'se, air pressure is applied to the oil in the power steering system and excess oil is forced to return through the relief valve 108. This is accomplished by the timer contact 378 in circuit 376 closing as indicated in the cycle chart at the end of the filling phase. Closing of contact 378 applies power to solenoid 382 of the blowback valve 130 which then opens. Power is also applied to solenoid 394 to open the blowback return valve 106. The energized lights 386 and 396 indicate that

valves

130 and 106, respectively, are open. Air at 35 p.s.i. is thus delivered by fill head port 116 to the power steering system at the top of the fill neck and forces the excess oil through the open foot valve 66, hose 5*0, hose 46 and open hose 104 to relief valve 108. Relief valve 108 opens at 30 p.s.i. to exhaust the excess oil to the receiver 110 while back pressuring the power steering system. The oil exhausted to receiver 110 is pulled back through the open hose 112 by vacuum pum 94 which returns the oil via line to the tank. When the oil level in the fill neck drops to the end of the snout 62 which is at the correct oil level 410 air then enters the foot valve 66 and no more oil forced out. Thus, the excess oil is forced out while the pressure is maintained in the power steering system to maintain the remaining air compressed. The blowback phase terminates when the timer contact 378 opens. The blowback phase is provided with sufficient time which is controlled by timer contact 378 to accomplish such excess oil removal as determined by the amount of excess oil and the blowback flow rate.

In the next phase of the cycle which is the venting phase the foot valve 66 in fill head is closed to trap the oil in the power steering system while the air pressure in the system is vented by opening the vent valve 128. This is accomplished by the timer contact 314 in circuit 312 being timed to open upon opening of the timer contact 378 as shown in the cycle chart. Opening of timer contact 314 deenergizes coil 300. With coil 300 deenergized, contact 300 in circuit 318 is opened to deenergize solenoid 320 causing valve 80- to close fill head foot valve 66. Contact 300' in circuit 294 is opened upon deenergization of coil 300 and with the timer contact 296 still closed, power is applied to solenoid 302 to open vent valve 128.

The cycle is terminated by the timer contact 296 opening to deenergize the master timer 288. All of the remaining timer contacts have previously opened. The solenoid 302 is thus deenergized to close the vent valve 128 and the cycle indicating light 284 goes off. The operator may now disconnect the fill head from the fill neck. The master cycle timer is returned to its start position by the action of a return spring, not shown, when the solenoid clutch 292 is deenergized and thus the filling apparatus is conditioned for the next cycle.

After the venting or decompressing phase, the oil level in the fill neck will raise slightly, /2 to 1 being observed in an actual filling operation, because of the remaining air in the power steering system expanding. The power steering pump at vehicle engine start on the assembly line after the filling operation generates pressure in the system to compress the air and the oil level drops back to the correct level. Continued operation of the steering system bleeds out all of the remaining air and the level will then be correct with the vehicle engine running or shut off.

Assuming now that a power steering system like system 16 is to be filled the operator attaches the fill head 12 to the fill neck 20 and closes the start switch 272. Closing of switch 272 energizes coil 276 which then closes contact 276" to apply power to the master cycle timer 28 8. With the master cycle timer energized, the timer contact 296 closes to provide a holding circuit for timer 288 and coil 276 through the closed contact 276". Contact 276' is opened by the energized coil 276 so that the indicator light 284 for fill head 10 is not energized. Light 286 is energized to indicate the fill head 12 is in use.

The relay coil 276 selects the correct solenoid valves for the filling cycle using fill head 12. This is accomplished by the energized coil 276 opening contact 276" in circuit 318 to prevent energization of solenoid 32% so that foot valve 66 in fill head 10 cannot open while closing contact 276"" in the same circuit to permit energization of solenoid 322 and thus opening of foot valve 68 in fill head 12. Energized coil 276 also opens contact 27 6" in circuit 376 to prevent energization of solenoid 382 so that the blowback valve 130 serving fill head 10 cannot open while closing contact 276"" in the same circuit to permit energization of solenoid 384 and thus opening of the blowback valve 134 serving fill head 12. The fill head

vent control valves

128 and 132 are both operated when either the fill head 10 or 12 is used.

The remaining sequence of operation of the filling apparatus using fill head 12 is the same as described above for the fill head 10 except as noted above.

The start-

stop switches

246 and 252 for the pump motors are provided so that the operator can override the automatic cycle to stop either one or both of the pumps. The various jog switches are provided so that the operator can override the automatically timed cycle to control the different phases of the filling operation.

The above-described preferred embodiment is illustrative of the process and the apparatus according to the present invention which may be modified within the scope of the appended claims.

We claim:

1. A method of establishing a desired liquid level in liquid receptacles which may contain varying amounts of liquid and thus initially contain no liquid or have an initial liquid level which may be low comprising the steps of (a) evacuating almost all of the air in the receptacle,

(b) filling the receptacle with a liquid under pressure to compress the remaining air and establish a liquid level higher than the desired level with the receptacle under pressure,

(c) applying gas pressure to the receptacle to bring the liquid level down to the desired level while maintaining the receptacle under pressure, and

(d) equalizing the receptacle pressure with atmospheric pressure while preventing the escape of liquid.

2. The method set forth in claim 1 and preventing the filling in step (b) in the event a predetermined vacuum is not established in step (a).

3. The process set forth in claim 2 and automatically controlling the establishment and time period of each said stop.

-4. A method of establishing a correct oil level in a power steering system having a power steering pump fill neck and an initial oil level which is low comprising the steps of (a) sealingly connecting to the fill neck a fill head having a hollow probe projecting into the fill neck so that the probe end is at the correct oil level.

(b) applying a vacuum through the probe to withdraw almost all of the air from the power steering system,

(c) delivering oil under pressure through the probe to the power steering system to compress the remaining air and establish an oil level higher than the correct oil level with the power steering system under pressure,

(d) applying air pressure through a passage in the fill head to the top of the oil to force oil out through the probe end until the correct oil level is reached while maintaining the power steering system under pressure,

(e) closing the probe to trap the remaining oil in the power steering system, and

(f) venting the power steering system through the fill head passage to the atmosphere.

5. The method set forth in claim 4 and preventing steps (c), (d), (e) and (f) in the event leakage occurs and a predetermined vacuum is not established in step (a), automatically controlling the establishment and time period of each said step.

6. A liquid filling apparatus for establishing a correct liquid level in a liquid receptacle which may contain varying amounts and thus have no liquid or have a low liquid level comprising the combination of air evacuating means operatively connected to the receptacle for evacuating almost all of the air in the receptacle, pressurized liquid filling means operatively connected to the receptacle for filling the receptacle with liquid under pressure to compress the remaining air and establish a liquid level higher than the correct liquid level with the receptacle under pressure, gas pressure means operatively connected to the receptacle for applying gas pressure to force liquid out of the receptacle to bring the liquid level down to the correct level While maintaining the receptacle under pressure, and venting means operatively connected to the receptacle for venting the receptacle to the atmosphere.

7. The liquid filling apparatus set forth in claim 6 and an electrical control circuit operatively connected to said air evacuating means, said liquid filling means, said gas pressure means, and said venting means for automatically timing the operations thereof.

8. Apparatus for establishing a correct oil level in a power steering system having a power steering pump with a fill neck comprising the combination of a vented tank;

a vacuum pump having intake and discharge passages; said vacuum pump discharge passage connected to said tank; a pressure pump having intake and discharge passages; said pressure pump intake passage connected to said tank; a fill head having a hollow probe insertable into the fill neck so that the probe end is at the correct oil level; a fill head hose; a valve in said fill head operable to connect and disconnect said fill head hose and the power steering system via said probe; fluid passage means including a fill valve operable to connect and disconnect said pressure pump discharge passage and said fill head hose, a bypass valve operable to connect and disconnect said pressure pump discharge passage and said tank and a first pressure relief valve operable to connect said pres sure pump discharge passage to said tank only at a predetermined pressure; fluid passage means including a vacuum line with a vacuum valve operable to connect and disconnect said vacuum pump intake passage and said fill head hose; a passage in said fill head exposed to the top of said fill neck between said probe and said fill neck; a vent, blowback hose connected to said fill head passage; an air pressure source; a blowback valve operable to connect and disconnect said vent, blowback hose and said air pressure source; a vent valve operable to open and close said vent, blowback hose to the atmosphere; a receiver; fluid passage means including a second pressure relief valve operable to open to said receiver only at a predetermined pressure and a return valve operable to connect and disconnect said fill head hose and said second pressure relief valve; and fluid passage means including a purge valve operable to connect and disconnect said receiver and said vacuum line at a point between said vacuum valve and said vacuum pump close to said vacuum valve.

9. The apparatus set forth in claim 8 and an electrical control circuit operatively connected to control all of said valves except said relief valves operable in an evacuating condition to open said vacuum valve, said fill head valve and said bypass valve while maintaining all of the other controlled valves closed, further operable in a filling condition to open said fill valve and said purge valve and close said vacuum valve and said bypass valve while maintaining said fill head valve open and all of the other controlled valves closed, further operable in a blowback condition to open said return valve, said bypass valve and said blowback valve and close said fill valve while maintaining said fill head valve and said purge valve open and all of the other controlled valves closed and further operable in a venting condition to open said vent valve and close said return valve, said blowback valve and said fill head valve while maintaining said purge valve and said bypass valve open and all of the other controlled valves closed.

10. The apparatus set forth in claim 9 and timer means in said electrical control circuit for automatically establishing and timing all of said conditions.

11. The apparatus set forth in claim 10 and a vacuum switch in said electrical control circuit having its sensor connected to said fill head hose for preventing the establishment of said filling, blowback and venting conditions in the event a predetermined vacuum is not established during said evacuating condition.

12. The apparatus set forth in claim 8 and another fill head for connecting the apparatus to another power steering system having a power steering pump with a fill neck and a different correct oil level, said other fill head having a hollow probe with a different length so that its end upon insertion into the diflerent fill neck is at the difierent correct oil level, another fill head hose connected to said first mentioned fill head hose, a valve in said other fill head operable to connect and disconnect said other fill head hose and the other power steering systern via said other probe, a passage in said other fill head exposed to the top of the other fill neck between said other probe and the other fill neck, another vent, blow back hose connected to the passage in said other fill head, a blowback valve operable to connect and disconnect said other vent, blowback hose and said air pressure source, a vent valve operable to open and close said other vent, blowback hose to the atmosphere.

13. The apparatus set forth in claim 12 and an electrical control circuit operatively connected to control all of said valves except said relief valves operable to open said vacuum valve and said bypass valve and selectively open one of said fill head valves while maintaining all of the other controlled valves closed, further operable in a filling condition to open said fill valve and said purge valve and close said vacuum valve and said bypass valve while maintaining the selected fill head valve open and all of the other controlled valves closed, further operable in a blowback condition to open said return valve and said bypass valve and selectively open the blowback valve associated with the selected fill head valve and close said fill valve while maintaining the selected fill head valve and said purge valve open and all of the other controlled valves closed and further operable in a venting condition to open both said vent valves and close said return valve and the selected blowback and fill head valves while maintaining said purge valve and said bypass valve open and all of the other controlled valves closed.

References Cited UNITED STATES PATENTS 2,660,350 11/1953 Fechhcimer 141-1 FOREIGN PATENTS 486,641 9/1952 Canada. 788,014 12/ 1957 Great Britain.

LAVERNE D. GEIGER, Primary Examiner EDWARD J. EARLS, Assistant Examiner US. Cl. X.R. 14148, 61, 116

P0405) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,460,591 Dated Auqust l2. E1969 Inventor) Arthur A. Chalenski, Jr. and Walton Hughes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 59, "vacuume" should read vacuum Column 6, line 72, "value" should read valve Column 7, lines 1. and 2, "normaly" should read normally Column 8, line 9, "contract" should read contact Column 9, line 65, after "cycle" and before the comma insert chart SIGNED AND SEALED APR? 1970 (SEAL) Attest:

Edward M. FlewherJr- WILLIAM E. 503mm, m. Attesting Officer 5i0ner or Patents