Abstract Hoist of the high free-lift type with three pairs of masts, for lift trucks, comprising a plate carrying forks slidable in the guides of the innermost pair of masts, the latter being slidable in the guides of the pair of movable intermediate masts sliding in turn in the grooves of the pair of fixed masts, a telescopic cylinder with two pistons, namely a smaller and a larger piston, mechanical transmission means adapted to transmit the movements from the cylinder to the plate and thereafter to the movable masts, and abutment means for carrying the pair of intermediate masts along, in which the smaller piston is connected to the plate to obtain, with respect to the cylinder, movements of the plate twice those of said smaller piston, and the larger piston is connected to the pair of fixed masts to obtain movements of the cylinder with respect to the fixed masts three times those of the larger piston with respect to the cylinder itself, the thrust area of the larger piston being practically one and a half times the thrust area of the smaller piston.
A hoist, comprising, in combination: a first pair of fixed masts; second and third pairs of masts movable with respect to each other and to said first pair of masts; a load-carrying plate slidably connected to said third pair of masts; a single cylinder arrangement carried by said third pair of masts; first and second telescoping piston members movably extending from said cylinder in opposite direction, wherein the thrust area of one of said first and second piston members is one and one-half times the thrust area of the other of said first and second piston members; and wherein the movement of said loadcarrying plate with respect to said cylinder is approximately twice as great as the movement of said second piston with respect to said cylinder; a first pulley mounted on said first piston member; a second pulley; means connecting said second pulley to said cylinder; first and second flexible means; means connecting one end portion of said first flexible means to at least one of said first masts; means connecting a second end portion of said first flexible means to said first piston member; said first flexible means being trained at least partially around said first and second pulleys; a third pulley mounted on said second piston member; means rigidly connecting one end portion of said second flexible means to said cylinder; and means connecting a second end portion of said second flexible means to said load-carrying plate; said second flexible means being trained at least partially around said third pulley.
Claim 2
Dependent Claim
253 words
A hoist, comprising, in combination: a first pair of fixed masts; second and third pairs of masts movable with respect to each other and to said first pair of masts; a load-carrying plate slidably connected to said third pair of masts; a single cylinder arrangement carried by said third pair of masts; first and second telescoping piston members movably extending from said cylinder in opposite direction, wherein the thrust area of one of said first and second piston members is one and one-half times the thrust area of the other of said first and second piston members; and wherein the movement of said loadcarrying plate with respect to said cylinder is approximately twice as great as the movement of said second piston with respect to said cylinder; a first pulley mounted on said first piston member; a second pulley; means connecting said second pulley to said cylinder; first and second flexible means; means connecting one end portion of said first flexible means to at least one of said first masts; means connecting a second end portion of said first flexible means to said first piston member; said first flexible means being trained at least partially around said first and second pulleys; a third pulley mounted on said second piston member; means rigidly connecting one end portion of said second flexible means to said cylinder; and means connecting a second end portion of said second flexible means to said load-carrying plate; said second flexible means being trained at least partially around said third pulley.