Fork loader with lift-controlled enclosure

Claim 2

A loading device comprising a fork with a pair of loadengaging prongs depending from a common head portion provided with elongate guide means; a connecting member movably secured to said head portion by said guide means; biasing means tending to maintain said connecting member in a normal position relative to said head portion; hoisting means engaging said connecting member at an acute angle to said guide means for urging same into an off-normal position, against the force of said biasing means, upon upward movement of said hoisting means with reference to said prongs weighted down by an engaged load; an enclosure for said load including a mobile front part adapted to give access to said load in an upwardly retracted position; and transmission means linked with said front part and engageable by said connecting member in said normal position thereof for normally holding said front part in said retracted position while enabling said front part to descend forwardly of the load upon a lifting of the weighted fork by said hoisting means.

Claim 3

A device as defined in claim 1 wherein said guide means comprises a cylinder, said connecting member being a plunger received in said cylinder, said biasing means including an air cushion in said cylinder.

Claim 4

A device as defined in claim 2 wherein said plunger has a free end provided with a roller, said transmission means including a pivotal shaft for said front part offset from the direction of movement of said plunger and a cam on said shaft normally in contact with said roller.

Claim 5

A device as defined in claim 2 wherein said prongs terminate in a pair of fortines diverging forwardly from the axis of said cylinder whereby the latter is upwardly inclined in a horizontal position of said tines.

Claim 6

A device as defined in claim 1, further comprising detent means on said fork for latching said front part in its lowered position, and spring-loaded actuating means for said detent means normally holding same in a withdrawn position, said actuating means being positioned for engagement by said connecting member subsequently to disengagement thereof from said transmission means for releasing said detent means from said withdrawn position.

Claim 7

A device as defined in claim 1 wherein said hoisting means includes a hydraulic cylinder and piston movable relatively to each other to generate hydraulic pressure upon the exertion of an upward force to a suspension point of said hoisting means, said fork being provided with hydraulic clamping means juxtaposed with said prongs for gripping a load in response to said hydraulic pressure.

Claim 8

A loading device comprising a fork with a pair of load-engaging prongs depending from a common head portion; a connecting member movably secured to said head portion; biasing means tending to maintain said connecting member in a normal position relative to said head portion; hoisting means engaging said connecting member for urging same into an off-normal position, against the force of said biasing means, upon upward movement of said hoisting means with reference to said prongs weighted down by an engaged load; an enclosure for said load including a mobile front part adapted to give access to said load in an upwardly retracted position; and transmission means linked with said front part and engageable by said connecting member in said normal position thereof for normally holding said front part in said retracted position while enabling said Front part to descend forwardly of the load upon a lifting of the weighted fork by said hoisting means; said hoisting means including a hydraulic cylinder and piston movable relatively to each other to generate hydraulic pressure upon the exertion of an upward force to a suspension point of said hoisting means, said fork being provided with hydraulic clamping means juxtaposed with said prongs for gripping a load in response to said hydraulic pressure.

Claim 9

A loading device comprising a fork with a pair of load-engaging prongs depending from a common head portion; a connecting member movably secured to said head portion; biasing means tending to maintain said connecting member in a normal position relative to said head portion; hoisting means engaging said connecting member for urging same into an off-normal position, against the force of said biasing means, upon upward movement of said hoisting means with reference to said prongs weighted down by an engaged load; an enclosure for said load including a mobile front part adapted to give access to said load in an upwardly retracted position; and transmission means linked with said front part and engageable by said connecting member in said normal position thereof for normally holding said front part in said retracted position while enabling said Front part to descend forwardly of the load upon a lifting of the weighted fork by said hoisting means; said hoisting means including a hydraulic cylinder and piston movable relatively to each other to generate hydraulic pressure upon the exertion of an upward force to a suspension point of said hoisting means, said fork being provided with hydraulic clamping means juxtaposed with said prongs for gripping a load in response to said hydraulic pressure.

Claim 10

A device as defined in claim 7 wherein said head portion is provided with elongate guide means for said connecting member, said hoisting means being coupled with said connecting member at an acute angle to said guide means.

Claim 11

A loading device comprising a fork with a pair of load-engaging prongs depending from a common head portion; a connecting member movably secured to said head portion; biasing means tending to maintain said connecting member in a normal position relative to said head portion; hoisting means engaging said connecting member for urging same into an off-normal position, against the force of said biasing means, upon upward movement of said hoisting means with reference to said prongs weighted down by an engaged load; an enclosure for said load including a mobile front part adapted to give access to said load in an upwardly retracted position; transmission means linked with said front part and engageable by said connecting member in said normal position thereof for normally holding said front part in said retracted position while enabling said front part to descend forwardly of the load upon a lifting of the weighted fork by said hoisting means; detent means on said fork for latching said front part in its lowered position; and spring-loaded actuating means for said detent means normally holding same in a withdrawn position, said actuating means being positioned for engagement by said connecting member subsequently to disengagement thereof from said transmission means for releasing said detent means from said withdrawn position.

Claim 12

A loading device comprising a fork with a pair of load-engaging prongs depending from a common head portion; a connecting member movably secured to said head portion; biasing means tending to maintain said connecting member in a normal position relative to said head portion; hoisting means engaging said connecting member for urging same into an off-normal position, against the force of said biasing means, upon upward movement of said hoisting means with reference to said prongs weighted down by an engaged load; an enclosure for said load including a mobile front part adapted to give access to said load in an upwardly retracted position; transmission means linked with said front part and engageable by said connecting member in said normal position thereof for normally holding said front part in said retracted position while enabling said front part to descend forwardly of the load upon a lifting of the weighted fork by said hoisting means; detent means on said fork for latching said front part in its lowered position; and spring-loaded actuating means for said detent means normally holding same in a withdrawn position, said actuating means being positioned for engagement by said connecting member subsequently to disengagement thereof from said transmission means for releasing said detent means from said withdrawn position.

Claim 13

A device as defined in claim 9 wherein said enclosure further includes a rear part fixed with reference to said fork, said detent means comprising a pair of spring-biased locking pins mounted on opposite sides of said rear part for engagement with corresponding sides of said front part.

Claim 14

A device as defined in claim 10 wherein said actuating means comprises a spring-loaded camming lever and flexible link means connecting said lever with said pins, said transmission means including a pivotal shaft for said front part and a cam on said shaft, said connecting member being provided with a deflecting roller normally in contact with said cam and positioned to engage said camming lever upon disengaging said cam to facilitate a downward swing of said front part.

Claim 15

A device as defined in claim 11 wherein said connecting member comprises a plunger, said biasing means including a pneumatic cylinder on said head portion receiving said plunger, said head portion being provided with slotted lateral wings, said plunger carrying said deflecting roller on a free end thereof and being further provided with lateral roller means received in slots of said wings.