Fork lift truck driven by internal combustion engine

Claim 1

A system for controlling a load carrying device of a fork lift truck driven by an internal combustion engine, comprising: a carburetor having a throttle valve fixed to a throttle valve shaft disposed in said carburetor, said throttle valve being rotatably disposed in the air-fuel mixture induction passage of said carburetor, and a first lever fixedly mounted on the throttle valve shaft and mechanically connected to an accelerator of the engine; a manually operated control means for controlling the operation of the load carrying device, said manually operated control means including switching means for supplying therethrough electric current when a manually operable member of said manually operated control means is operated to operate the load carrying device; and means for partially opening said throttle valve by a predetermined amount from the fully closed position of said throttle valve in response to the movement of said manually operated control means, whereby the engine output power and engine speed are increased to increase the speed of the operation of the load carrying device, the throttle valve opening means including a second lever rotatably connected to the throttle valve shaft and having a stop which is engageable with said first lever, a diaphragm actuator including a casing, a diaphragm which divides the inside of the casing into an atmospheric chamber communicated with atmospheric air and a vacuum chamber communicated with a vacuum source through a vacuum passageway connecting the vacuum chamber to the vacuum source, a connecting rod connecting said diaphragm and said second lever, and a spring disposed in said casing to normally urge said connecting rod in the direction that the stop of said second lever is engaged to cause said first lever to rotate in the direction for opening the throttle valve by the predetermined amount, and a solenoid valve arranged to open the vacuum passageway to establish communication between the vacuum chamber and the vacuum source, or close the vacuum passageway to block the communication therebetween in response to the electric current supplied through said switching means.

Claim 2

A system for controlling a load carrying device of a fork lift truck driven by an internal combustion engine, comprising: a carburetor having a throttle valve fixed to a throttle valve shaft disposed in said carburetor, said throttle valve being rotatably disposed in the air-fuel mixture induction passage of said carburetor, and a first lever fixedly mounted on the throttle valve shaft and mechanically connected to an accelerator of the engine; a manually operated control means for controlling the operation of the load carrying device, said manually operated control means including switching means for supplying therethrough electric current when a manually operable member of said manually operated control means is operated to operate the load carrying device; and means for partially opening said throttle valve by a predetermined amount from the fully closed position of said throttle valve in response to the movement of said manually operated control means, whereby the engine output power and engine speed are increased to increase the speed of the operation of the load carrying device, the throttle valve opening means including a second lever rotatably connected to the throttle valve shaft and having a stop which is engageable with said first lever, a diaphragm actuator including a casing, a diaphragm which divides the inside of the casing into an atmospheric chamber communicated with atmospheric air and a vacuum chamber communicated with a vacuum source through a vacuum passageway connecting the vacuum chamber to the vacuum source, a connecting rod connecting said diaphragm and said second lever, and a spring disposed in said casing to normally urge said connecting rod in the direction that the stop of said second lever is engaged to cause said first lever to rotate in the direction for opening the throttle valve by the predetermined amount, and a solenoid valve arranged to open the vacuum passageway to establish communication between the vacuum chamber and the vacuum source, or close the vacuum passageway to block the communication therebetween in response to the electric current supplied through said switching means.