US3110517A

US3110517A - Controls for a vacuum handling device

Info

Publication number: US3110517A
Application number: US842927A
Authority: US
Inventors: John E Olson; Donald A Harris
Original assignee: Hyster Co
Current assignee: Hyster Co
Priority date: 1959-09-28
Filing date: 1959-09-28
Publication date: 1963-11-12
Anticipated expiration: 1980-11-12

Description

Nov. 12, 1963 I J. E. OLSON EI'AL 3,110,517

CONTROLS FOR A VACUUM HANDLING DEVICE Filed Sept. 28, 1959 :5 Sheets- Sheet 1 INVENTORS JOHN E OLSON y DONALD A. HARE/3 Buck/70m, Cheat/7dr}? (QB/Ore FROM ACCELERATOR PEDAL ATTORNEYS 1963 J. E. OLSON ETAL CONTROLS FOR A VACUUM HANDLING DEVICE :5 Sheets-Sheet 2 Filed Sept. 28, 1959 w w M w .8 w 4 w n m S E D M R R E 0 R 8 TNA R N H m E am W MT IE A L M W 6 0 @0 m h M u YB B 5 w w m Nov. 12, 1963 J. E. OLSON ETAI. 3,110,517 CONTROLS FOR A VACUUM HANDLING DEVICE 3 sheets-sheet s fined Sept. 28, 195.9

JOHN E OLSON DON/1L0 A. HARE/5 lNVE/VTORS. B) BUC/(HOR/V, BLORE, KLAROU/ST 8 SPAR/(MAN A7 7' ORA E Y5 United States Patent 3,110,517 CONTROLS FOR A VACUUM HANDLING DEVICE John E. Olson, Portland, Oreg., and Donald A. Harris, Vancouver, Wash, assignors to Hyster Company, Portland, Oreg., a corporation of Nevada Filed Sept. 28, 1959, Ser. No. 842,927 7 Claims. (Cl. 294-64) This invention relates to material handling equipment and particularly to material handling equipment for picking up loads with the aid of vacuum.

In the co-pending applications of Donald A. Harris, filed September 15, 1958, Serial No. 761,218, now Patent No. 3,040,920, entitled Method and Apparatus for Handling Loads; Paul L. Brainard, Donald A. Harris, Glenn E. I-Ierz, Harry G. Meister and Robert C. Shoemaker, filed December 22, 1958, Serial No. 782,269, now Patent No. 3,054,521, entitled Handling Methods and Apparatus; and Paul L. Brainard and James R. Aaron, filed March 23, 1959, Serial No. 801,224, entitled Methods and Apparatus for Handling Articles of Commerce and Packaging Methods and Packages, there are disclosed a number of vacuum material handling machines and methods, some of which are designed for use on the front end of an industrial lift truck or other vehicle.

One desirable feature of any material handling equipment is fast operation, both in picking up and depositing loads. It is relatively easy to quickly deposit a load, when handling material by way of vacuum, since the vacuum can be quickly broken or relieved. However, more difficulty is encountered in speedily picking up a load, because of the time consumed in creating a partial vacuum.

While a truck can be equipped with a large capacity vacuum pump, this would be very expensive and space consuming.

It is a main object of the present invention to overcome the above problem without the necessity of equipping the truck with a large capacity vacuum pump.

More particularly, it is an object of the invention to make use of the vacuum forming capabilities of the internal combustion engine of a material handling truck without adversely affecting the normal operation of the truck engine.

Another object of the invention is to provide a truck in which the full vacuum forming capacities of the engine are utilized Without materially impairing the operation of the engine.

A further object is to provide a control arrangement to facilitate the temporary use of the internal combustion engine of the lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to suction type load pick up means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, wherein said control arrangement so controls the communication of the suction means and the regular air inlet with the intake manifold that a load may be picked up using engine vacuum, transported from place to place with the engine operating normally, and then released.

Another object is to provide such an arrangement which includes an auxiliary air pump and auxiliary fuelair mixture control means interrelated with the other elements of the arrangement for desired engine operation and load pick up, transport and deposit.

Various other objects will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic view of a system incorporating the concepts of the present invention, the various elements 3,110,517 Patented Nov. 12, 1963 'ice I of the system being shown in positions for creating a vacuum at the vacuum head;

FIG. 2 is a perspective view of a linkage system for operating some of the valves of the system, the linkages being shown in positions to create a vacuum at the vacuum head;

FIG. 3 is a side view in elevation of part of an engine embodying the concepts of the present invention;

FIG. 4 is a top view taken in the direction of the arrows 44 of FIG. 3;

FIG. 5 is a partial schematic view showing a modified form of the invention; and

FIG. 6 is a diagrammatic view of a lift truck showing the control arrangement of FIG. 1.

Referring to the drawings, FIG. 1 shows a system for application to the internal combustion engine of an industrial lift truck 5. At the front of the truck, there is a vacuum head 11 for picking up a load 13, the head being connected, by passageway means to be described, to two sources of vacuum, a small-capacity, constantlydriven vacuum pump 15 and the internal combustion engine 16 which inherently provides a relativelylarge capacity air pump as'c'ompared to the vacuum pump 15. The engine 16 drives the pump as indicated by the'device 16a shown in broken lines in FIG. 6, but the pump could be driven by its own engine if desired. The passageway connecting means includes a suitable conduit 17 which includes a first portion 17a, usually in the form of a hose, which extends from the head to a second portion in the form of a duct 17b. Duct 17b is connected to an air filter housing 19. The pump 15 is connected by a suitable conduit 15a to the conduit 17 between the head 11 and the air filter housing. A butterfly valve 21 is mounted in an inlet pipe 23 to relieve the vacuum when it is desired to release a load. The valve is operated by a handle 24.

A gravity-operated flap valve 31 is mounted to close the upper end of the conduit 17 when the pressures on the opposite sides of the valve are approximately equal or when the pressure above the valve is greater than the pressure below the valve. For convenience, the valve is shown as being slidably mounted on a stem 33.

The 'air filter housing 19 has an air inlet 35 having a butterfly valve '37 operated by a manually-operated link age system L. The linkage system includes a handle 39 by which the various linkages of the system may be operated. The handle is located near the driver as indicated in FIG. 6. If the Vehicle is a conventional industrial lift truck as shown in FIG. 6, the engine may be located beneath or behind the driver. Under such circumstances, the handle 39 is located forwardly or to the left of the engine 16 as the parts are shown in FIG. 6, and the air filter 19 located near the driver. 7

The air filter housing 19, has the usual air filter element 41, and a suitable duct 43 leads from the housing to the carburetor 45. The carburetor has a barrel 46 within the lower part of which is a throttle valve 47 connected to the linkage system L.

There is a choke valve 48 above the venturi 49 of the carburetor barrel. The carburetor has a float chamber 50 connected by a vent 51 to the carburetor barrel above the throat of the venturi 49, and also connected by a passage or jet 52 to the barrel at the throat of the venturi. A duct 53 leads from the carburetor barrel to the intake manifold 55 on the engine 16.

A by-pass conduit 61 connects an extended part of the duct 43' to the carburetor outlet duct 53, and a flapper valve 63 controls the flow of air through the conduit 61. The flapper valve is also connected to the linkage L to be operated thereby. The purpose of the by-pass conduit will be explained later.

FIGS. 2, 3 and 4 show the incorporation of the concepts of the invention in an actual engine and show the construction of the linkage L. The linkage L includes a cable 71 connecting'the handle 39, shown in FIG. 1, to one end of an actuating lever 73, shown in FIG. 2. The lever is fixed to the shaft 75 of the air inlet valve 37. The other end of the lever 73 is connected by a rod 77 to an arm 79 fixed to one end of a flapper valve shaft 81. A flapper valve sleeve 83 freely fits on the shaft and has the valve 6-3 fixed thereto. The sleeve is cut away at one end to provide an annular segmental lug 85 which engages a pin 87 on the shaft 81 in the position of the parts shown in FIG. 2.

The end of the shaft 81 remote from the arm 79 has a pin 91 engaging an annular segmental lug 93 formed on a sleeve 95 freely fitting on the shaft. The sleeve has an arm 97 connected by a rod 99 to an arm 1111 fixed to a sleeve 163. The sleeve freely fits on a shaft 105 for the throttle valve 4 7 and is formed with an annular segmental stop 1G7 cooperable with a pin 1119 on the shaft 105 to facilitate movement of the shaft 105 and thus operation of the throttle valve 4 7.

Fixed to the shaft is an arm 111 connected by a rod 113 to one end of a bell crank 115, the latter being pivotally connected adjacent its other end to a seat member 117 forming part of a conventional governor 6. A spring 119 urges the bell crank to move counterclockwise While the governor Weights 121 urge the bell crank to move in a clockwise direction through the medium of a spindle 120. The weight arms 123 are pivoted on a tubular shaft 125 driven by a gear arrangement 127. It will be appreciated that the construction of the governor has been simplified for convenience in illustration.

A sleeve 13-1 freely fits on the sleeve 103 of the arm 101, the sleeve 13 1 having fixed thereto a bent arm 133 connected by a rod 135- to the foot throttle lever (not shown) of the vehicle which conventionally is mounted on the floor board. The arm 133- has the lower portion thereof bent to lie in the plane of the lower end of the arm 101. Thus, if the arm 133 is moved in a counterclockwise direction, as the parts are shown in FIG. 2, at a time when the arm 101 is pointing downwardly, the arm 133 will move the arm 101 just as if the arm had been pulled by the rod 99. However, it is here pointed out that the movement of the arm 101 by means of the arm 133 will not cause the shaft 81 to rock or turn because the rod 99 will merely turn the sleeve 95 in a clockwise direction to move the annular segmental lug 93 away from the pin 91. Thus, the flapper valve 63 will not be open when the throttle valve 47 is operated by the foot throttle.

Operation The head 11 has a resilient or elastomer. seal 301 around the periphery thereof for directly engaging the load. To create a vacuum at the head, the handle 39' is shoved to its full line operative position shown in FIG. 1 to swing the lever 73 to turn the valve 37 to its closed full line position shown in FIGS. 1 and 2. This action of the lever 73 also causes the shaft 81 to turn in a clockwise direction to rotate the pin 87 into engagement with the lug 85 on the sleeve 83 to open the valve 63.

Turning of the shaft 81 also swings the pin 91 clockwise to move the lug 93 and thus the arm 97 in a clockwise direction, to swing the arm 10 1 and the sleeve 103 in a counterclockwise direction to move the lug 107 away from the pin 109. This releases the governor weights 121 which push the rod 113 to the left to turn the arm 111 in a counterclockwise direction to open the throttle valve 47 sufliciently wide to bring the engine up to its high idle speed. It is pointed out that the governor is directly responsible for the increase of speed and not the operation of the arm 101. The arm 10 1 merely allows the lug 10 7 to release the pin 109 to enable the governor to turn the throttle valve 47.

It is pointed out that when the valve 6 3 is in its seated condition, the pin 87 will be spaced from the lug 85. Thus, the handle 39 may be moved partly toward its operative position to effect opening of the throttle valve 47 somewhat and lessen the pressure differential across the flapper valve 63, making it easier to open the flapper valve.

The increased speed of the engine draws a large amount of air through the carburetor 4 5 and also through the conduit 61 since the flapper valve 63 is open. Since the valve 37 is now closed, all this air is drawn from the head 11 to quickly draw the necessary vacuum to enable the head to pick up the load. The operator will watch a suitable pressure gauge, not shown, so that when the vacuum reaches a predetermined point, he throws the handle in a clockwise direction to open the valve 37, close the valve 63, partly close the throttle valve 47 and bring the governor back to its low speed position because of the engagement of the lug 107 with the pin 109. A spring 149 connected to the lever 73 actually restores the valves to their original positions when the handle 39 is so thrown. A spring 151 shown in FIG. 2 returns the lug 107 to its normal position, since movement of the shaft 81 in a counterclockwise direction, under the influence of the spring 149, will impart no movement to the arm 97.

Opening of the valve 37 immediately increases the pressure within the air filter housing and thus the flap valve 31 immediately closes to preserve the vacuum on the load. The vacuum pump 15 continues to run and has sufiicient capacity to maintain the desired vacuum in the head despite leakage of air that might occur at the load.

The lift truck can now be driven to a load depositing station at which time the handle 24- may be operated to open the valve 21 and release the vacuum and thus release the load.

A suitable relief valve 299 may be provided in the conduit 17 to limit the vacuum, particularly in case there is little or no leakage of air at the load. Instead of the valve 299', a relief valve 303 could be utilized and mounted in the head 11 as shown, preferably in the upper portion of the head. The valve seats against a seat 305 and is urged by a spring 3117 to assume a closed position. The spring surrounds a shank 309 of the valve, the shank providing an actuating member by which the valve may be unseated when the vacuum reaches a predetermined value. The shank length is selected so that when the vacuum creates a pressure suflicient to compress the elastomer seal against the load a desired extent, the valve is slightly opened to prevent drawing a higher vacuum.

The valve arrangement is automatically adjustable to provide a greater pressure on a heavier load than with a lighter load. This results as follows. When a heavy load is lifted, it tends to pull away from the upper portion of the seal 3111 while fulcruming on the lower portion with a force proportional to its weight. Since the valve 303 opens when the upper portion of the seal is compressed a predetermined extent, it is evident that it is going to take a greater pressure, and thus higher vacuum, to hold a heavy load against the upper seal portion with the desired compressing force than in the case of a light load.

T he ry of Operation The theory of operation of the arrangement of the present invention is believed understood, although if the theory is not correct, the following discussion will make it possible for others to receive the full benefits of the invention.

When the handle 39' is thrown to its operative position, that is, its vacuum head position, shown in full lines in FIG. 1, the air within the system soon becomes thin or rarefied. This drops the pressure in the carburetor. It is believed that the difierential pressure between the float chamber 51} and the venturizthroat 49 does not decrease with falling pressure in the system, or does not decrease suificiently to prevent an excess of fuel from being injected through jet 5-2. Hence the mix will be too rich and the engine would die were it not for the by-pass 61. The by-pass adds air to the mix with-out increasing the amount of fuel, and if the opening in the by-pass is properly adjusted, the oxygen in the by-pass air will make up for the deficiencies in oxygen in the venturi air and thus maintain a proper oxygen-fuel ratio. Thus, the engine can develop sufiicient power to overcome its internal friction and keep running at high idle speed to draw the desired vacuum quickly. It has been found that the engine can operate properly to draw the desired vacuum, around '15 inches of mercury, before the air becomes too thin for proper operation.

The way to find the desired size of the by-pass, or its desired effective size, is to provide a bypass with a crossseotional area of greater than one-half of the crosssectional area of the main air passage of the carburetor at a place in the carburetor having a pressure equal to that in the bypass. A manually operable butterfly valve, not shown, is installed in the by-pass and arranged in a closed position. is thrown to its operative position to cause a speed increase in the engine. The butterfly valve is then gradually opened manually until the maximum flow of air, that is, weight of air, is attained. This should bring the engine to approximately high idle speed. Then the butterfly valve is fixed in such position, or another conduit of the effective size of the conduit containing the adjusted butterfiy valve is substituted for the old conduit.

If the above is done, the proper air-to-fuel ratio will be attained whether the air pressure within the duct 43 is around atmospheric or below atmospheric pressure.

Modification Referring to FIG. 5, an automatic metering valve 169 may be provided in conduit 61. The valve has an arm 171 connected to a piston 173 in a cylinder 175 which has its upper end open to atmospheric pressure. A spring 177 urges the valve to a closed position. A conduit 17'9 con meets the lower end of the cylinder to the duct 43. When the duct pressure drops, the atmospheric pressure above the piston depresses the piston thus progressively opening the valve. Thus, at the first stroke of the engine in the evacuation process no by-pass air is fed to the engine, but as the pressure drops, the bypass is open to enable the passage of bypass air in proportion to duct pressure.

Having described the invention in what is considered to be the preferred embodiment thereof, it is desired that it be understood that the invention is not to be limited other than by the provisions of the following claims.

We claim:

1. A control arrangement to facilitate the temporary use of the internal combustion engine of a lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold, said arrangement including,

passageway means leading from a regular air inlet to said intake manifold and from said suction means to said intake manifold and placing said suction means in parallel with said regular inlet,

said suction means being exposed to the atmosphere when not in contact with a load,

control means for closing said regular air inlet to enable said engine to act as a vacuum pump and create a subatmospheric pressure at said suction means to enable a load to be picked up,

said control means also being operable to open said air inlet for normal engine operation, while precluding the flow of air from said manifold to said suction means and from said regular air inlet to said suction means to avoid loss of the subatmospheric pressure at said suction means.

2. A control arrangement to facilitate the temporary use of the internal combustion engine of a lift truck as With the engine running, the handle 39 6 a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold and a carburetor having a venturi, said arrangement including,

passageway means leading from a regular air inlet to said carburetor and from said suction means to said carburetor and placing said suction means in parallel with said regular inlet, said suction means being exposed to the atmosphere when not in contact with a load, control means for closing said regular air inlet to enable said engine to act as a vacuum pump and create a subatmospheric pressure at said suction means to enable a load to be picked up, said control means also being operable to open said air inlet for normal engine operation, while precluding the flow of air from said manifold to said suction means and from said regular air inlet to said suction means to avoid loss of the subatmospheric pressure at said suction means, auxiliary means in addition to the carburetor venturi for automatically controlling the fuel-air mixture during the period of use of said engine as a vacuum pump to avoid excessive fuel supply, and auxiliary vacuum pump means communicating with said suction means for supplying subatmospheric pressure to said suction means at times at least including those periods when said truck is carrying a load and said engine is not acting as a; vacuum pump. 3. A control arrangement to facilitate the optional use of the internal combustion engine of a lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold, said arrangement including,

first valve means for controlling the flow of regular air to said engine,

passageway means having a first portion leading from said first valve means to the intake manifold of said engine,

said passageway means having a second portion leading from said suction means to said first portion at a place between said first valve means and said manifold,

second valve means for said second passageway portion for preventing the fiow of air toward said suction means from the remainder of said passageway means, but allowing flow in the opposite direction,

third valve means communicating with said second passageway portion between said second valve means and said suction means,

means for closing said first and third valve means so that said engine creates a subatmospheric pressure at said suction means to facilitate picking up a load, or [for opening said first valve means without opening said third valve means to facilitate normal operation of said engine and maintenance of said subatmospheric pressure at said suction means, or for opening said third valve means to release said load.

4. A control arrangement to facilitate the optional use of the internal combustion engine of a lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold and a carburetor having a venturi, said arrangement including,

first valve means for controlling the flow of regular air to said engine,

passageway means having a first portion leading from said first valve means to the intake manifold of said engine, said passageway means including said carbu- 7 retor, said passageway means having a second portion leading from said suction means to said first portion at a place between said first valve means and said manifold,

second'valve means for said second passageway portion for preventing the flow of air toward said suction means from the remainder of said passageway means, but allowing flow in the opposite direction,

third valve means communicating with said second passageway portion between said second valve means and suction means,

means for closing said first and third valve means so that said engine creates a subatrnospheric pressure at said suction means to facilitate picking up of a load, or for opening said valve means without opening said third valve means to facilitate normal operation of said engine and maintenance of said subatmospheric pressure at said suction means, or for opening said third valve means to release said load,

auxiliary means in addition to carburetor venturi for automatically controlling the fuel-air mixture during the period of use of said engine as a vacuum pump to avoid excessive fuel supply,

and auxiliary vacuum pump means communicating with said second passageway portion at a place between said second valve means and said suction means for supplying subatmospheric pressure to said suction means'at times at least including thoserperiods when said truck is carrying a load and said engine is not acting as a vacuum pump.

5. A control arrangement to facilitate the optional use of the internal combustion engine of a lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold, said arrangement including,

air filter means communicating with said intake manifold,

a regular air inlet providing for the passage of air to and through said air filter means to said intake manifold,

passage means placing said suction means in communicat-ion with said air filter means for the passage of air from said suction means to and through said air filter means to said intake manifold,

said passage means being the sole means for passage of air from said suction means to said intake manifold,

said passage means communicating with said intake manifold only through said air filter means,

control means for preventing flow of air to said manifold from said regular air inlet to enable said engine to act as a vacuum pump and create a subatmospheric pressure at said suction means to enable picking up a load,

said control means also being operable to open said air inlet for normal engine operation, while precluding the flow of air from said manifold to said suction means and from said regularair inlet to said suction means to avoid loss of the subatmosphenic pressure at said suction means.

6. A control arrangement to facilitate the optional use of the internal combustion engine of a lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold, said arrangement including,

passageway means leading from a regular air inlet to said intake manifold and from said suction means to said intake manifold and placing said suction means in parallel with said regular inlet, control means for preventing flow of air to said manifold from said regular air inlet to enable said engine to act as a vacuum pump and create a subatmospheric prwsure at said suction means to enable picking up a load, 1

said control means being also operable to speed up the operation of said engine concurrently with the just mentioned action,

7. A control arrangement to facilitate the optional use of the internal combustion engine of a lift truck as a large capacity vacuum pump for supplying subatmospheric pressure to load pick up suction means on said truck, or to facilitate use of the engine as a prime mover for powering said truck from place to place, said engine having an intake manifold and a carburetor for supplying said intake manifold with a combustible mixture, said carburetor having a venturi, said arrangement including,

passageway means iead-ing from a regular air inlet to said intake manifold and from said suction means to said intake manifold and placing said suction means in parallel with said regular inlet, control means for preventing flow of air to said manifold from said regular air inlet to enable said engine to act as a vacuum pump and create a subatmospheric pressure at said suction means to enable picking up a load,

said control means also being operable to open said air inlet for normal engine operation, while precluding the flow of air from said manifold to said suction means and from said regular air inlet to said suction means to avoid loss of the subatmospheric pressure at said suction means,

said auxiliary means including a passage in parallel with the carburetor of said engine,

said control means opening such passage when said engine is functioning as a pump and closing said passage at other times.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3. 110,517 November 12, 1963 John E. Olson et a1.

ears in the above numbered pat- It is hereby certified that error app rs Patent should read as ent requiring correction and that the said Lette corrected below.

Column 7, line 11 before "suction means" insert said Signed and sealed this 5th day of May 1964.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J BRENNER Attesting Officer Commissioner of Patents

Claims

1. A CONTROL ARRANGEMENT TO FACILITATE THE TEMPORARY USE OF THE INTERNAL COMBUSTION ENGINE OF A LIFT TRUCK AS A LARGE CAPACITY VACUUM PUMP FOR SUPPLYING SUBATMOSPHERIC PRESSURE TO LOAD PICK UP SUCTION MEANS ON SAID TRUCK, OR TO FACILITATE USE OF THE ENGINE AS A PRIME MOVER FOR POWERING SAID TRUCK FROM PLACE TO PLACE, SAID ENGINE HAVING AN INTAKE MANIFOLD, SAID ARRANGEMENT INCLUDING, PASSAGEWAY MEANS LEADING FROM A REGULAR AIR INLET TO SAID INTAKE MANIFOLD AND FROM SAID SUCTION MEANS TO SAID INTAKE MANIFOLD AND PLACING SAID SUCTION MEANS IN PARALLEL WITH SAID REGULAR INLET, SAID SUCTION MEANS BEING EXPOSED TO THE ATMOSPHERE WHEN NOT IN CONTACT WITH A LOAD, CONTROL MEANS FOR CLOSING SAID REGULAR AIR INLET TO ENABLE SAID ENGINE TO ACT AS A VACUUM PUMP AND CREATE A SUBATMOSPHERIC PRESSURE AT SAID SUCTION MEANS TO ENABLE A LOAD TO BE PICKED UP, SAID CONTROL MEANS ALSO BEING OPERABLE TO OPEN SAID AIR INLET FOR NORMAL ENGINE OPERATION, WHILE PRECLUDING THE FLOW OF AIR FROM SAID MANIFOLD TO SAID SUCTION MEANS AND FROM SAID REGULAR AIR INLET TO SAID SUCTION MEANS TO AVOID LOSS OF THE SUBATMOSPHERIC PRESSURE AT SAID SUCTION MEANS.