US2785770A - Liquid or lubricant injectors - Google Patents

Description

March 19, 1957 C. C. S. LE CLAIR LIQUID 0R LUBRICANT INJECTORS Original Filed April 17, 1948 5 Sheets-Sheet l Inventor Camille Clm' SkranKHns L8, Clair Atlorney:

March 19, 1957 c. c. 5. LE CLAIR 0 LIQUID OR LUBRICANT INJECTORS Original Filed April 17, 1948 5 Sheets-Sheet 2 4 I A a I r I I Inventor camlufi d'e pvavfl ina L5 Clair A Horney:

C. C. 5. LE CLAIR LIQUID OR LUBRICANT INJECTORS v March 19, 1957 5 Sheets-Sheet 4 Original Filed April 17, 1948 Inventor C'umlllc CIA": SpIQnKHn LC Clair y M MoL Jim/um A ttorneys United States Patent ice 2,785,770 LIQUID 0R LUBRICANT INJECTORS Divided and this application July 13, 1953, Serial No. 367,633

Claims priority, application Great Britain April 29, 1947 7 Claims. (Cl. 184-7) The present invention relates to liquid or lubricant injectors and this application is a division of co-pending application Serial No. 21,634, filed April 17, 1948, and issued January 26, 1954, as U. S. Patent No. 2,667,235 for Liquid or Lubricant Distribution Systems.

One object of the present invention is to provide an injector for supplying measured charges of lubricant to one or more places of use, comprising a body member, a substantially constant capacity pumping means in said body member having an inlet through which lubricant may be supplied to said injector and a discharge outlet, means forming an accumulator chamber in said discharge outlet for receiving a portion of the discharge from said pumping means, and means to adjust the volume of said accumulator chamber for varying the lubricant receiving capacity thereof and thereby varying the volume of lubricant discharged through said outlet when the pumping means is operated.

A further object of the invention is to provide an injector for discharging measured charges of lubricant comprising a body member, a pump chamber in said body member, a fluid pressure operated plunger for discharging a substantially constant volume of lubricant from said pump chamber, means forming an inlet to said pump chamber, means forming an outlet from said pump cham ber, means for supplying motivating fluid to said injector for operating said plunger to discharge lubricant from said outlet, yieldable means energised during the discharge stroke of said plunger for initiating return movement of the plunger, means for supplying lubricant under a predetermined pressure to said inlet forming means for recharging said injector, said inlet forming means including a passageway having an opening in said pump chamber which is uncovered when said plunger is moved under the influence of said yieldable means to thus admit lubricant under pressure to the pump chamber to complete the return movement of said plunger.

Several constructional forms of the present inventio as applied to grease dispensing systems are shown, by way of example, on the accompanying sheets of drawings, whereon:

Figure l is a sectional view showing some parts in elevation of one form of injector which comprises an airoperated piston and plunger, a single normally illuminated injector lamp and two normally open injector switches which are in parallel with the lamp circuit, one of which is closed when the piston and plunger complete their discharge strokes, the other being closed when the piston and plunger complete their charge stroke, the injector lamp being short-circuited and extinguished in either case;

Figure 2 is a section on the line 22 in Figure 1, the injector lamp and its switches being omit-ted from the figure;

Figure 3 is a section on the line 33 in Figure 2, showing air and grease ports and passages;

Figure 4 is a section on the line 4-4 in Figure l, the injector lamp and its switches being omitted from the figure;

2,785,770 Patented Mar. 19, 1957 Figure 5 is a section on the line 55 in Figure 1 showing air and grease ports and passages;

Figures 6 and 7, which are to be read together, show a number of the injectors, the air container, the air compressor, the grease pump and the electric motor for driving the air compressor and the grease pump;

Figure 8 is a sectional view, showing some parts in elevation, of a modified form of injector which is fitted with two lamps, and which comprises two normally-open injector lamp switches, one of which is in parallel with each of the lamps and is closed when the injector completes a discharge or charge stroke, the respective lamp being thereby extinguished in either case;

Figure 9 is a sectional view showing some parts in elevation of a modified form of injector which comprises a single injector lamp and two normally closed injector switches in series therewith, one switch being opened when the injector carries out a full discharge stroke, while the other is opened when the injector carries out a full charge stroke, the lamp being extinguished in either case; and

Figure 10 is a section on the line 1010 in Figure 9.

Referring first to Figures 1 to 5 In this constructional form of the invention each injector includes a high pressure air-operated metering pump or injector comprising a hollow cylinder 1 to one end of which is fitted a pump body 2 in which an injector plunger 3 is slidable. The injector plunger is reciprocated by means described hereinafter and it is adapted to open a grease inlet port 4 in the pump body towards the end of its suction or charge stroke to the left and to close it again early in its discharge stroke to the right. The end of the injector plunger remote from the inlet port 4 is connected to the crown 5 of an air-operated piston 6 which is slid-ably arranged in the cylinder 1. A coil spring 7 reacts between the end of the cylinder and the inside of the piston crown 5 and urges the piston 6 and plunger 3 outwards so that the latter uncovers the inlet port.

Each injector cylinder and pump is detachably attache to a fixed injector base or body casting 11, Figures 2 to 5, to which the air and grease conduits hereinafter referred to are attached. Within the injector body 11 are formed the necessary passages for connecting the said conduits to the air and grease cylinders, and also for connecting the pump discharge passage 8 with the outlet connection 9. All these passages pass through the jointing face 27A (see Fig. 5) where the detachable cylinder 1 and pump body 2 joint the fixed injector body 11. There are also other passages in the injector body to accommodate electrical conductors.

Delivery of grease from the pump body 2 is made through a discharge passage 17 (see Fig. 1) past a dis charge valve 12, through passages 17a, 17b, 17c ail-d8 (see Fig. 3) to an outlet connection 9 which is formed in a boss 10 projecting downwards from the fixed injector body 11, see Figures 1, 3 and 4. This outlet connection is connected by a pipe (not shown) to the place of use of the grease. For a purpose to be described later, the discharge valve 12, Figure l, is fitted with a piston 13 provided with a sealing ring 300 and slidable in a bore or cylinder 14 (which comprises an accumulator chamber or means) formed in the end of the cylinder 1, the piston and valve being urged by a spring 15 in a direction normally to hold the valve on its seat 16, which latter is arranged at the end of the discharge passage 17 connected.

' with'two laterally projecting arms 33 and 39.

after, this constitutes a method of adjusting the amount of grease discharged per stroke of the plunger 3 to the place of use.

Leading into the discharge passage 3 is a subsidiary passage 19, Figure 3, having its outer end closed with a grease nipple 20. This arrangement is provided so that, in the event of a failure of the injector to function, a grease gun may be applied to the nipple and a temporary supply of grease supplied to the place of use.

A sliding buffer 21, Figure I, loaded by a spring 362, is fitted on'the side of the crown 5 of the injector piston w6'remote from the pump body 2 upon an extension 301 of the injector plunger 3 and isso arranged that it strikes a shoulder 22 formed in a recess 23 provided in a cover .24 closing the open end of the injector cylinder 1 towards the end of the injector plunger charge stroke, after the grease inlet port 4 has been uncovered by the plunger 3 .but before an injector switch, referred to hereinafter, has

.short-circuited an injector lamp 25. The spring-loading of the butter 21 issuch that it will not-collapse under the influence of the coil spring 7 acting upon the injector piston6 and plunger 3 but will collapse under the added load when the grease supply pressure is applied to the plunger'3, as will be explained hereinafter.

Each injector body 11 is integral withthe rear wall 26 '(see Fig. 4), the two endwalls 27 and part of the bottom-wall .28 of .a housing 29 for the injector switches and lamp. The housing is closed by a cover 39 which comprises the top and front wall 31 and the remaining part 32 of the bottom wall of the housing. A rectangular openjing is formed in the front wall of the cover and is closed by a glass panel 33, preferably colored.

The injector switch comprises a lever 34-, Figure l,

suspended in pendulum-fashion from a screw 35, the lower end 36 of the lever'being bent at right angles so as to engage in a slot 37 in the wall of the injector piston 6, see Figure 4. Between its ends the switch lever is formed switchesfare arranged on opposite sides of the lever, one of the switches comprising two flexible contact-carrying blades .40 and 41 and the other two similar blades 42 and 43." Thearm 38 is so positioned that, when the lever 34 is swung into ,its extreme position by the piston 6, moving =to the-end of its charge stroke, it engages the flexible blade 41, of a swi-tch 4tl-41 and forces the contact carried there- .on into engagement with the contact on the blade 40, thus closing the switch. Similarly, when the lever 34 is swung Two into its other extreme position by the piston 6, moving to the end of its discharge stroke, the arm 39 engages the blade43 of a switch 42-43 and thrusts the contact carried thereon into engagement with the contact on the blade 42thus closing the switch.

The switch4041 is man injector lamp circuit which includes the -lead 46, the terminal bracket 44, lead 47, blades 41, 49, lead 48 and lead 49 which is connected to the'terminal bracket 45 and lead 59. Thus, when the switch-40. 41 is closed, the two lamp terminals are shortcircuited and the lamp is extinguished, this taking place if and when the injector piston 6 and the plunger 3 complete their stroke to the left as shown in Figure l, i. e., the charge stroke.

Similarly, the switch 42-43 is in an injector lamp circuit which includes the lead 50, terminal bracket 45, lead 49, blades 43, and 42, leads 51 and 47, terminal bracket and th'e contacts with which it co-operates is such that Whenthelever is moved by the injector piston 6 to either As exyplained above, the arrangement of the switch lever 34 the two lamp terminals, .50 that current passing through the circuit does not pass through the lamp and the latter is extinguished. If, however, the injector piston 6 and plunger 3 fail to complete their mutual full stroke in,

57 formed in the opposite end.

As shown inFigure 6, the longitudinal air and grease passages 52 and 53 of the injector bodies in the system are connected in series by lengths'58 and 59 of air and grease-conveying hose respectively, which in turn are connected to sources of supply of air and grease.

The longitudinal air passage 52 in each injector body 11 is connected bysubsidiary passages 66, 61 and 62 (see Fig. 5) to the space 63, Figure 1, between the cover v24 closing the open end of the injector operating cylinder 1 and the crown 5 of the injector piston 6. V g

The longitudinal grease passage .53 in each injector body 11 is connected by subsidiary passages 64 and 64a (see Fig. 5) to the inlet port 4 of the pumpbody and also by passages 65 and 65a to thelspace 66 above the discharge valve piston 13, so that in certain circumstances the valve 12 is held upon its seat 16 by the pressureof the grease as will be explained hereinafter.

The said compressed air source for operating the pistons 6 of all the injector devices in the system comprises a container 67, Figure 7, which is connected by a main air duct 68 and main air line 68a to the, air conveying hose 58 and which is fed with air from an air compressor 69, which latter is preferably driven from a single phase electric motor 70 which also serves to drive a main grease pump 71. A relief valve 72 on the air container is set to blow off at a predetermined pressure (say 30 lbs. per square inch) and there is also a pressure-operated switch 73 which is associated with the main air duct 68 leading which is operated by the core 76 of a solenoid 77 in such a manner that when the solenoid is energised the valve is pulled downwards, into such a position that the main air container 67 'is put into communication with the air lines 6811 and 58 and thus with the pistons 6 of all the injectors, the exhaust connection being cut ofi, and when the solenoid is de-energised, the main valve is thrust upwards by the spring 78 intoa position in which the supply of compressed air to the said air line 68a is cut OE and the cylinders are all put into communication withthe atmosphere via the air line 68a and the exhaust connection 90.v g

. The grease supply source comprises the main grease pump 71 which is driven by the same motor as the air compressor 69, and having its starting device relay operated by means of a solenoid. The main grease'pump draws its supply from a container 91 and delivers the grease under pressure through V a main grease line 92 to the grease-conveying hose 59 connecting withall'the injector devices.

The main grease line 92 is fitted with a spring-urged grease relief valve whichcomprises a plunger'94 slidable in the bore of a hollow body 95 and arranged to cover and uncover an outlet port 95a. This plunger is attached end of its travel it'closes aswitch'and thus short-circuits 15;

'to a piston 96 which is slidable in a bore of larger. diameter in the same body. The piston and plunger are urged .5 by a spring 97 acting on the top of the piston downwards past the outlet port 95a so that the plunger closes the latter. The bottom end of the plunger is exposed to the pressure of grease in the said main grease line 92 through a branch pipe 98 and the load on the spring 97 on the top of the piston is such that it requires a pressure of say, 400 lbs. per square inch to open the outlet port 95a.

The outlet port 95a is connected by an escape pipe 99 to the grease container 91 so that grease delivered by the pump in excess of requirements is returned to the container.

A compressed air inlet port 100 is formed in the grease relief valve casing below the piston 96 and is connected to the main air line 68a at a point between its connection to the air-conveying hose 58 and the casing of the main air control valve 75 in such manner that the cyclical changes of air pressure as applied to the injector pistons 6 by the control valve are also applied to the underside of the piston 96 of the grease relief valve.

For a reason to be explained hereinafter, the respective diameters of the piston 96 and plunger 94 of the grease relief valve are so arranged that, when the operating air pressure acts upon the underside of the piston, the piston and plunger are moved upwards against the opposing pressure of the piston spring 97, thus opening the outlet port 95a and relieving the grease charging pipe 92 of all pressure.

The closing of a main-switch (not shown) starts up the motor 70, which drives the grease pump 71, and the air-compressor 69 which will run until a predetermined pressure of say 25 lbs. per square inch has been built up in the receiver 67, at which point the pressure switch 73 will come into operation and cut out the motor 70.

During this operation, the grease pump 71 will have pumped into the system such grease as it will accept to charge the pipes, passages, etc. and any excess will have been discharged through the relief valve 94, and escape pipe 99, back to the supply tank 91.

Thereafter the operation of the system is as follows:

At the start of the discharge strokes of the injectors the main air valve solenoid 77, Figure 7, is energised and pressure air is admitted to all the injector pistons 6 which immediately move forward, simultaneously thrusting the pump plungers 3 before them on their discharge strokes.

During this operation, pressure air from the main air duct 68a, Figure 7, is also admitted to the space below the piston 96 on the relief valve 94 of the grease supply source. This, as previously explained, lifts the relief valve causing the lowering of the grease pressure in the grease supply line 92 to zero. Thus, pressure is relieved from the piston 13 of the injector discharge valves 12, which are consequently free to lift, and thus there is no detraction from the full force of the injector pumps which, consequently, is available for delivery of grease to places of use.

It will be appreciated that part of the volume of the injector pump delivery will be absorbed in thus lifting the discharge valve piston 13 and that the volume of grease so used will not reach the place of use. Hence, by varying the amount of lift permissible by the insertion or removal of washers 18, the amount of grease so used can be varied. The variation of the piston lift therefore affords a ready means of varying the net volume delivered by the injector to the place of use. While the injector pistons are in motion, i. e., are in some position intermediate the two ends of their strokes, the injector switches 40--41 and 42 -43 will be open and the injector lamps 25 will not be short-circuited, and consequently they will remain illuminated. As each injector plunger 3 completes its stroke its particular switch makes contact, short-eircuiting and extinguishing its particular lamp.

Thus, if the apparatus is functioning correctly all the injector pistons and plungers will complete their discharge strokes in between say 10-15 seconds or possibly less, and all the injector lamps will be extinguished.

If, on the other hand any one or more injector piston and plunger fails to complete its stroke, that particular injector lamp will remain illuminated after the others have gone out.

At a predetermined time in the discharge stroke, if any one or more of the injector pistons 6, and plungers 3, has or have by that time still failed to complete its or their discharge stroke, or strokes, that particular injector switch 42, 43, will have failed to short-circuit the particular lamp 25, with which it is associated, and this lamp will accordingly remain illuminated as previously explained.

At a predetermined time in the injector discharge stroke the said main air valve solenoid 77 is tie-energised and the core 76 accordingly moves back, under the influence of its spring 78 into the position were the pressure air from the air container 67 is shut oft from the main air line 68a and the injector pistons 6 are exposed to the atmosphere through the air outlet from the main air valve. The injector pistons 6 will then return under the influence of their springs 7 causing a void to be formed or creating a vacuum in the pump chambers 2.

The main grease pump motor starter-74 is energized, thus closing switches and starting the motor and the pump 71. The grease under a pressure of 400 lbs. per square inch (as limited by the relief valve 94 as previously explained) is then forced forward through the aforesaid grease ducts 92 and hose 59 to the bodies 2 of all the injector pumps which, however, it does not immediately enter.

Since the grease pressure is also applied to the upper side of all the injector discharge valve pistons 13, these with their discharge valves 12 will descend until the valves re-seat themselves. The grease below the pistons which is displaced by this movement will be returned to the pump chambers and will follow the pump plungers 3, filling the aforesaid void until the discharge valves 12 are reseated.

Thereafter, the plungers will continue to move on their return strokes, causing a further void until the aforesaid butiers 21 contact their stops 22 on the cylinder cover 2 -3. By this time, however, the grease inlet ports 4 have been uncovered by the plunger so that fresh grease under pressure from the supply source then enters through the inlets 4, fills the remaining void and charges the pumps with a fresh supply, building the pressure up to that of the grease supply line. Since, however, the grease pressure has already been applied to the upper sides of the discharge valve pistons 13 the discharge valves 12 which have already seated themselves as previously explained, will be held in the closed position so that no unmetered grease will be permitted to pass to the places of use.

As soon as the pressure in the pump chambers builds up, the added load on the pump plungers 3, due to the pressure of the grease on the ends of the plungers, as already explained, is sufficient to overcome the thrust of the spring 362 on the piston bufiers 21 which, therefore, collapse and allow the pistons 6 and the plungers 3 to complete their charge strokes.

It will be noted that the amount of fresh grease entering each injector pump from the supply source is the swept volume of the pump less the amount thrust back by the movement of the discharge valve piston 13. Hence, by varying the amount of the movement of the valve piston 13 and thereby the amount of grease returned, the amount accepted from the grease source and ultimately delivered to the place of use may be varied.

The completion of the injector charge strokes serves to close the switches 40-41 and short-circuit the injector lamp terminals, as previously explained and, it should .be' noted, this only takes place if the pumps have not only completed their charge strokestbut also have been re- .plenished with grease up to the full working pressure.

Ifthe apparatus is functioning satisfactorily,jthe, re- .turn or charge strokes, commenced under the influence of the injector piston springs 7 and finished by the charg- :ing of the pumps with the incoming grease underpres- .sure, should be completed in anything between, say, --15-secs, and possibly less. t

i It should be noted that, during theperiod of the charge stroke while the main grease pump 71 is running, the air compressor 69 which is driven by the same motor 70, is also running and thus replenishing the airreceiver 67 with air to replace the air used in the previous discharge .stroke. a i

Any air in excess of requirements is discharged through the air relief valve 72 in the normal'manner. V

-As-each injector piston and plunger completes its stroke that particular lamp will be short-circuited and extinguished and, thus, if all complete their strokes all the .lamps will be extinguished. If, however, one or more iof the pistons and pllmgers fail to complete their mutual strokes the associated lamp or lamps will remain alight.

.Ifat any predetermined time in the charge stroke any one or more of the injector pistons 6 and plungers 3 has, or have, by that time failed to complete its, or their, charge stroke or strokes, that particular injector switch -41 willihave failed to short-circuit the particular lamp 25 with which it is associated and this lamp will accordingly remain illuminated as previously explained. "If, on the other hand, all the injector plungers 3 have completed their strokes, and the chargingof the pumps is also completed, all the injector lamps 25 will be shortcircuited as previously explained.

-.Attl1e end of thecharge strokes, the lubricant pump motor 71 issto'pped.

It will be obvious that the constructional features of the invention as described above may be modified. For

example, ina first modified construction each individual.

injector, instead of being fitted-with a single lamp 255 which remains illuminatedin case of a fault on either stroke may befitted. with two lamps which may be diflferently coloured. Thus, for example, a fault on a discharge stroke may bring about the lighting of a green lamp and a fault. on a charge stroke may bring about the lighting of a red lamp.

Such a modification is shown in Figure 8. In this construction, each injector is similar in construction to the injectors shown in Figure 1 and each, therefore, briefly,

cornprises an'air-operated piston fizz-fitted with a return spring 7a, and a plunger 3:: slidable in a pump body 2a and controlling the opening and closing of a grease inlet 'port 4a. 7, p 7

The injector also comprises a pendulous switch lever 34a which is suspended from a screw 35:: and the lower end 3611 of which is bent inwards and engages in a slot 37:: in the injector piston 6a. The lever also has two lateral switchoperating arms 38:: and 39a.

This construction, however, comprises two injector lamps and 171, Figure 8, referred to hereinafter respectively as the charge and discharge lamps, which are normally extinguished, each being arranged behind a window of the type shown at 33, Figures 2, 4 and 6, which wiudows in this case are preferably differently coloured. Thus, the charge lamp 179 may be arranged behind a lred-window and the discharge lamp 171 behind a green window. p

When the injector piston 6a moves on its charge stroke, i e., to the left, the arm 38a is adapted to engage with the flexible switchblade 172 of the switch 172-173 and thus force the contact on the blade into engagement with the "contact'onthe. other flexible switch blade 3.73 thus closing the switch. When the injector piston 6!! moves on its to engage with the flexible switch'blade 174 of the switch dischargestroke', i. e., to the right, the arm 39a is adapted 174- 175 and this force the contact on the blade into engagement with the contact on the flexible switch blade-175 a which includes the terminal bracket 179, a lead 182, blade 175, blade 174, lead 183, and terminal bracket 178. When the injector piston 64 completes a discharge stroke the switch 174-175 is closed and the discharge lamp 171 is shortcircuited. 7

instead of being arranged to make a contact (thereby short-circuiting the injector lamp) at the end of each stroke, each injector switch may be arranged to'break a contact (thereby extinguishing the injector lamp) at the end of each stroke.

In this second modified construction which is shown in Figure 9, the injector switch comprises a lever member 34b, pivotatlly mounted on a screw 35b. At the sides of the switch'housing are a charge switch and a discharge switch, respectively having flexible blade members 196, 197 and 198, 199, the contacts on which .are normally closed. The injector. also includes a single injector lamp 290 which is mounted on two terminal brackets 201 and 292. The lever is provided withlateral arms 38b and 39b which are arranged to engage and deflect the blades .196 and 199'respectively when the lever is swung by the injector piston 6b to the ends of its stroke. When one of these blades'is thus deflectedbythe arm 38b or 3912 on the lever, that particular switch of which the blade forms part is opened.

In this construction, the two injector lamp switches are in series with each other and with the injector lamp 200 which together fonn part of a circuit including a lead 204, blades196,'197, lead 295, terminal bracket 201,.lamp ZfiiL'terminal bracket 202, lead 206, blades 198, 199 and lead 207. e

If, after a fixed time from the start of the discharge stroke all the injector plungers '31: have completed their strokes all the blades 199 of the injector discharge switches 198-199 will be deflected and all the circuits opened so that no current will pass, and hence none of the injector lamps will light up.

If, however, one injector plunger 3b has failed to complete its stroke, the blade 199 of the discharge switch associated with'that plunger will not be deflected and the circuit will notbe broken. Hence, that particular injector lamp 290 will light up.

The discharge valve of the injector may be held on its seat during the charging operation by electro-magnetic 'means instead of by grease pressure as described above with reference to Figure 1 Such a construction is shown in Figure 8 in which the dischargevalve 12a is shown fitted in a piston part 13a which, however, merely serves as a guide and is formed with longitudinal grooves 241 to ensure the passage of grease from one side to the other of the piston part. The cylinder 14:: in which the piston part is housed is threaded at242 and into it is screwed an iron casing 243 containing a solenoid coil 244. The solenoid is fitted with an armature comprising a plunger type core spring 248, although this is not essential, the upward -movement of thearmature being limited by the non:

magnetic cover 249' of the casing 243. I

The arrangementis such that when the solenoid 244 is energised the armature'245, 246 is pulled downwards and holds the discharge valve 12a on its seat, and when the solenoid is de-energised the valve is free to lift.

The solenoid coil 244 is incorporated in a circuit so that when the circuit is closed the discharge valve 12a is held on its seat during the charging operation as in the case of the construction shown in Figure 1.

The injector piston spring, under the influence of which the piston and plunger are moved on their mutual return or charge stroke up to the point where the inlet port of the pump is open but the injector switch has not functioned, may be omitted and the piston and plunger may be returned by grease pressure only, the latter being supplied through an inlet valve and not through a port in the pump wall uncovered by the plunger towards the end of its stroke.

Thus, referring to Figure 10, the discharge valve 12b, its piston part 13b, its housing 14b, the plug type cover and its spring 1512 are all exactly the same as in the construction shown in Figure l.

The inlet valve body 250 carries a flexible valve 251 and is formed with longitudinal grooves 252 to permit the passage of grease. The valve is slidably mounted in a bore 254 and is urged upwards by a spring 255 and held against a seat 256 formed on the lower face of the cover plug 257. A passage 258 connects the grease supply passage 259 (which corresponds with the passage 65a in Figures 1 and 5), with the cross passages 260 in the plug 257 and thence With a longitudinal passage 261 in the plug. A continuation of the passage 258 to the left connects the grease supply with the space above the discharge valve piston 1315.

In this construction the charging of the injector plunger body 2b is performed as follows: grease under pressure from the source is admitted through the passage 259 and passes through the passage 258 to the right, as shown in Figure 10, past the inlet valve 251 and thence via a passage 262 to the pump chamber 263 where, by virtue of its pressure, it forces the injector plunger 312, see Figure 9, and its actuating piston 6b backwards to the end of their mutual stroke thereby recharging the pump. During this operation, grease also passes through the passage 258 to the left and exerting its pressure on the upperside of the discharge valve piston 13]) holds the discharge valve 12b on its seat so that no unmetered grease can escape to the place of use, as described in connection with the main construction.

It will be understood, of course, that the electro-magnetic means of holding the discharge valve 13b down on its seat as described above with reference to Figure 8 might alternatively be applied in this modified construction.

In a modification of the switch arrangement shown in Figure 1, the switch comprises a fiat contact member which is slidably guided for movement in the injector switch housing parallel to the movement of the injector piston 6 and plunger 3.

The contact member is provided with an arm which projects downwards through a hole in the bottom of the housing and engages in a slot cut in the skirt of the injector piston, so that the contact member will be recipro cated to and fro by the reciprocating motion of the injector piston and plunger. The width of the said slot in the piston skirt is greater than the width of the contact arm so that a certain amount of lost motion is allowed between the arm and the injector piston. Thus, the contact member is only moved at each end of the piston stroke while at other times it is held in a neutral or mid-position by springs acting on the opposite ends of the member.

The said injector lamp or lamps is or are arranged in front of the injector switch and behind the said glass panel. The arrangement of the sliding contact member and the contacts with which it co-operates is such that when the member is moved by the injector piston to either end of its travel it makes contact and short-circuits the 16 lamp terminals, so that, as explained hereinbefore, current passing through the circuit does not pass through the lamp and the latter is not illuminated.

This type of switch is more particularly applicable to the constructions described with reference to Figures 1-7 and 8.

Further, the pressure fluid for supplying the energy to operate the injector pistons and plungers may be other than compressed air, for example, water or oil, derived either from an included or an extraneous source.

The control of the electric signals and impulses by the injector pistons may be effected by means other than the mechanical movement of electric contact members as used in the various constructions described above, for example:

(a) By the use of mercury tubes or the more normal exposed metal or carbon contacts, or

(b) By the movement of a portion or the whole of a magnetic system in relation to the coil which excites it, e. g., a solenoid may be moved relatively to a plunger or the armature of a horse-shoe magnet.

(c) By the relative movement of two electro-magnetic coils, whether they are provided with iron circuits or not, in such a manner that the mutual induction between them is varied.

(d) By the movement relatively to one another of the component parts of an electro-static condenser.

(e) By the variation of the pressure applied to a piezo-electric crystal held in between two or more electrodes.

(f) By the variation of the pressure applied to a carbon pile or similar pressure sensitive resistance elements.

While the invention has been more particularly described with reference to lubricant distribution systems making use of piston or plunger type injectors it is not limited thereto. Injectors of any other suitable type may be used such as, for example, those making use of flexible diaphragms or of deformable chambers or other elements which are adapted to be deformed mechanically for the purpose of varying their volume.

I claim:

1. An injector for discharging measured charges of lubricant comprising a body member, a substantially constant capacity lubricant pumping means in said body member having an inlet through which lubricant may be supplied to the said injector and a discharge outlet, accumulator means communicating with said pumping means and said discharge outlet, valve means to control the flow of lubricant from said pumping means to said accumulator means and discharge outlet, valve operating means including means reciprocable in said accumulator means in response to the pressure of the lubricant discharged by said pumping means to open said valve, the extent of movement of said valve operating means in a valve opening direction determining the portion of the accumulator means available to receive lubricant from said pumping means, means to vary the stroke of said valve operating means in a valve opening direction and thereby vary the relative portions of the discharge of said pumping means flowing to said accumulator means and to said discharge outlet, and means to apply the pressure of lubricant at said inlet to said valve operating means before lubricant under pressure is admitted to said pumping means to move said valve operating means in a direction to close said valve before lubricant is admitted to said pumping means.

2. An injector for discharging measured charges of lubricant comprising a body member, a substantially constant capacity pumping means in said body member having an inlet through which said pumping means is supplied with lubricant under pressure and a discharge outlet, an accumulating cylinder communicating with said pumping means and discharge outlet, valve means reciprocable in one direction in said accumulator cylinder under the influence of the pressure of the lubricant 11 discharged by said pumping means to open communication between the pumping means and discharge outlet and increase the capacity of the accumulator cylinder available to receive lubricant from said pumping means, and means to apply the pressure of the lubricant at said inlet to the other side of said valve means before lubricant is admitted to said pumping means to cause said valve means to close communication between the pumping means and the lubricant discharge outlet and cylinder to exclude lubricant from the side of said accumulator cylinder communicating with said pumping means.

3. An injector for discharging measured charges of lubricant comprising a ,body member, a substantially constant capacity pumping means in said body member having an inlet through which said pumping means is supplied with lubricant under pressure and a discharge outlet, an accumulator cylinder communicating with'said pumping means and discharge outlet, valve means re- .ciprocable in'one direction in said accumulator cylinder under the influence of the pressure of the lubricant discharged by said pumping means to open communication between the pumping means and discharge outlet and increase the capacity of the accumulator cylinder available to receive lubricant from said pumping'means, and means to apply the pressure of the lubricant at said inlet to the other side of said valve means before'lubricant is admitted to said pumping means to cause said valve means to close communication between the. pumping means and the lubricant discharge outlet and cylinder to exclude lubricant from the side of said accumulator cylinder communicating with said pumping means, said valve means having differential areas subject to the pressure of the lubricant at said inlet and the discharge side of said dumping means for maintaining the valve closed during charging of the injector.

4. An injector for discharging measured charges of lubricant comprising a body member, .a substantially constant capacity pumping means in said body member having an inlet through which said pumpingmeans is supplied with lubricant under pressure and a discharge outlet, an accumulator communicating with said pumping means and discharge outlet, valve means reciprocaible in one direction in said accumulator under the influence of the pressure ofthe lubricant discharged by said pumping means to open communication between the pumping means and the discharge outlet'and increase the capacity of the accumulator available to receive lubricant from said pumping means, electromagnetically operated means to move said valve in a direction'to close communication between said pumping means and the accumlator and discharge outlet, and control means to effect energisation of said electromagnetically operated means for closing said valve means before lubricant is admitted to said pumping means.

5. A lubricant injector comprising pump means, first conduit means forming an inlet to saidrpump means,

duit means, and means for rendering said valve means effective to. block said second conduitmeans and being actuated by lubricant acting on said valve means through said further conduit means. i 7

6. A lubricant injectorcomprising a plungenmeans defining a plunger chamber, means mounting said plunger for reciprocation in said chamber to provide a substantially constant pumping capacity, first conduit means "forming an inlet to said chamber, means for supplying lubricant under pressure to said first conduit means, second conduit means forming an outlet from. said chamber, valve means interposed in said second conduit means, said second conduit means including an accumulator chamber, means for adjusting the size of said accumulator chamber to vary the volume of lubricant discharged by said plunger, further conduit means extending between said first conduit means and said valve means, and means for rendering said valve means effective to block said second. conduit means and being actuated by lubricant acting through said further conduit means.

7. A lubricant injector comprising a plunger, means defining a plunger chamber, means mounting said plunger for reciprocation in said chamber to provide a substantially constant pumping capacity, first conduit means.

forming an inlet to said chamber, secondconduit means forming an outlet from said chamber, valve means interposed in said second conduit means, said second conduit means including an accumulator chamber, said valve means being positioned in said accumulator chamber, means for adjusting the size of said accumulator chamber to varythe lubricant discharged by said plunger, whereby, when said valve means is operated to permit flow of lubricant through said second conduit means, said accumulator chamber becomes substantially filled before the lubricant emerges from said chamber and the volume of lubricant discharged by the injector may be adjusted by varying the size of saidaccumulator chamber, further conduit means extending between said valve means and' said first conduit means, means for rendering said valve means effective to block said second conduit means and being actuated by lubricant acting on same through said further conduit means, said first conduit means terminating in a port formed in the end of said plunger chamber, and check valve means interposed in said first conduit means downstream of said further conduit means whereby the return stroke of .said plunger is eifected by the incoming lubricant'under pressure.

References Cited in the file of this patent UNITED STATES PATENTS 1,496,306 Duhamel June 3, 1924. 1,698,159 Goddard "Jan. 8, 1929 1,743,968 Hatfield Jan. 14,1930

, 1,773,660 Barks Aug. 19, 19.30 1,807,059 Carpenter May 26, 1931 2,157,970 Rowland May 9, 1939 FOREIGN PATENTS 28,191 Great Britain 1911 121,646 Germany June 25, 1901 am M

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