Patent GB-985698-A (GB)
Title: Improvements in mobile equipment for picking up loads using an internal combustion engine as a source of vacuum
Inventor: OLSON JOHN ELMER
IPC: B66F9/18
Filed: 1961-03-21
Abstract: 985,698. Regulating I.C. engines. HYSTER CO. March 21, 1961, No. 10308/61. Heading FIB. [Also in Division B8] In an arrangement for controlling the use of an I.C. driving engine 16, Fig. 1, of a lift truck for use as a vacuum pump which actuates a load pick-up suction head 11, passages lead from the regular air inlet 35 and the suction head to the inlet manifold and control means 37, 31 restrict the regular air inlet during load pick-up suction and preclude air flow to the suction head during normal engine operation. A vacuum is created at the load pick-up head 11, having a peripheral elastomeric seal 301, when handle 39 is moved to the full line position to close valve 37, Fig. 2, and open valve 63 through link 71 levers 73, link 77 levers 79, shaft 81, pin 87 and lug 85 on sleeve 83. This also releases governor weights 121, Fig. 3, through pin 91, lug 93, sleeve 95, arm 97, link 99, arm 101 and lug 107 which moves away from pin 109, so that the governor action on rod 113 through crank 115 turns arm 111 and opens throttle valve 47 sufficiently to bring the engine to its high idle speed. All the engine air is drawn either through the carburettor 45 or through by-pass conduit 61. At a predetermined degree of vacuum, the handle 39 is moved to open valve 37 close valve 63, partly close throttle valve 47 and bring the governor back to its low speed position. The pressure rise in air filter housing 19 results in closure of flap valve 31 to preserve the vacuum in head 11 which is maintained at a desired level by an engine-driven vacuum pump 15. The vacuum and load are released by operation of handle 24 connected to valve 21. A vacuum limiting relief valve may be provided at 182 or 184 the latter being automatically adjustable to provide a greater effort on heavier loads than with lighter loads. The valve 63 does not open when valve 47 is actuated through the foot throttle. A manually-operable calibrating butterfly valve may be arranged in conduit 61. In a modification, an automatic metering valve may be provided in conduit 61 so that no by-pass air is fed to the engine at the first stroke but as the duct pressure drops the by-pass is opened proportionally to duct pressure. In an embodiment a truck 188, Fig. 6, has a suction head 11 connected by conduit 17 to air filter housing 19 of engine 16. An auxiliary pump 15, driven by its own engine 189 provides a further vacuum source. When head 11 contacts the load a switch 221, Fig. 7, is closed and solenoid valve 205 is energized through normally closed load releasing switch 223 and vacuum sensing switch 225, to cause actuation of linkage L, which in turn causes engine 16 to speed up by operation of throttle 47, and closes valve 37. At the same time solenoid valve 233 is energized to connect actuator 235 to the head 11 and the resulting drop in vacuum permits actuator spring 241 to move the throttle of the auxiliary engine to its fast position. At a predetermined degree of vacuum, the sensing switch 225 deactivates linkage L. Lifting of the head 11 by means of the truck hoist cylinders increases the pressure in the tilt cylinders 192 to move plunger 271, Fig. 9, above lever 275 to prevent clutch pedal 217, Fig. 8, from being depressed sufficiently to open the load releasing switch 223. Loss of vacuum is signalled by light 301. Subsequent depression and release of clutch pedal 217 and movement of gear lever 281, Fig. 10, closes the load release valve 21 either through pin 279 or chain 283, acting through lever 251. In a modified electrical circuit Fig. 11 a  switch 221a is positioned on the hoist cylinder lever and replaces the load contact switch and controls the energizing of a relay coil 305. In a further modification vacuum responsive means associated with the solenoid valve 205 may replace switch 225. The control system may be incorporated into power shift or automatic transmissions. Various types of suction heads which may be fitted are described and are also described in a divided Specification 985,699 [see Division B8]. Specification 923,856 also is referred to.