A hydraulic oil-circuit system and a hydraulic jack are proposed. The hydraulic oil-circuit system includes a hydraulic cylinder, an oil loading chamber, a storage oil chamber and an oil unloading pipeline; a piston is arranged in the hydraulic cylinder and divides the hydraulic cylinder into a first hydraulic oil chamber and a second hydraulic oil chamber; the first hydraulic oil chamber has a first oil port, and the second hydraulic oil chamber has a second oil port; the first oil port and the second oil port are both in unidirectional communication with the oil loading chamber and are both in unidirectional communication with the storage oil chamber; and the oil unloading pipeline connects the oil loading chamber and the storage oil chamber.

A jack, comprising: a top plate adapted to contact a load; a base plate positioned below the top plate; at least one actuator coupled perpendicularly between the base plate and the top plate; wherein the at least one actuator is operable to move the top plate between a lowered position and a raised position to thereby lower and raise the load; and, at least one locking assembly adapted to lock the top plate in the raised position.

A push-up system for heavy loads comprising multiple lift modules that are usable to collectively support and raise a load, wherein each lift module is capable to receive a support beam on top of it, and wherein the support beam is placeable on top of the lift module in at least one of a first direction and a second direction which traverses the first direction, and wherein each lift module is equipped with supports for the support beam, wherein the supports are swivably mounted at an upper end of the lift module and arranged to be displaceable between a first position wherein the support's guiding surface is horizontal and a second position wherein the supports are swiveled away from the first position so as to arrange that the support's guiding surface is perpendicular with said upper face of the lift module.

A push-up system for heavy loads comprising multiple lift modules that are usable to collectively support and raise a load, wherein each lift module is capable to receive a support beam on top of it, and wherein the support beam is placeable on top of the lift module in at least one of a first direction and a second direction which traverses the first direction, and wherein each lift module is equipped with supports for the support beam, wherein the supports are swivably mounted at an upper end of the lift module and arranged to be displaceable between a first position wherein the support's guiding surface is horizontal and a second position wherein the supports are swiveled away from the first position so as to arrange that the support's guiding surface is perpendicular with said upper face of the lift module.

A jack, comprising: a top plate adapted to contact a load; a base plate positioned below the top plate; at least one actuator coupled perpendicularly between the base plate and the top plate; wherein the at least one actuator is operable to move the top plate between a lowered position and a raised position to thereby lower and raise the load; and, at least one locking assembly adapted to lock the top plate in the raised position.

A device for amplifying a force includes a prime mover configured to receive a first force, and a secondary mover configured to generate a second force that is greater than the first force in response to the prime mover receiving the first force. The prime mover includes an output that, in response to the first force, rotates about a first axis through a power stroke defined by an angular displacement that is less than ninety degrees. The prime mover's output includes a first end that revolves about the first axis during the power stroke. The secondary mover includes an input, an output, and a body. The input includes a second end that is coupled with the first end of the prime mover's output, and that, as the first end of the prime mover's output revolves about the first axis through the power stroke, the second end of the secondary mover's input also revolves about the first axis and moves relative to the secondary mover's body. The secondary's mover's output is configured to apply the second force to an object. The secondary mover's body is releasably and pivotally anchored at a position such that as the first end of the prime mover's output revolves about the first axis through the power stroke, the body of the secondary mover pivots about a second axis that passes through the position, and such that as the first end approaches the end of the power stroke, the first end of the prime mover's output accelerates, without an additional force applied to the prime mover's output.

A transportable lifting device (10) comprising: an upright (12); an arm (13) connectable to the upper end of said upright (12); a diagonal (14) for connecting said arm (13) and said upright (12); characterized in that said arm (13) is fixed to said upright (12) by means of a first joint (30, 35); said diagonal (14) is fixed to said upright (12) by means of a second joint (32, 41); said diagonal (14) is fixed to said arm (13) by means of a third joint (36, 40); said first joint (30, 35), said second joint (32, 41) and said third joint (36, 40) are of the type with double tenon and mortise; said first joint (30, 35) comprises: two hooks (35) placed at the end of the arm (13); two vertical slots (30) placed on the upright (12).

A transportable lifting device (10) comprising: an upright (12); an arm (13) connectable to the upper end of said upright (12); a diagonal (14) for connecting said arm (13) and said upright (12); characterized in that said arm (13) is fixed to said upright (12) by means of a first joint (30, 35); said diagonal (14) is fixed to said upright (12) by means of a second joint (32, 41); said diagonal (14) is fixed to said arm (13) by means of a third joint (36, 40); said first joint (30, 35), said second joint (32, 41) and said third joint (36, 40) are of the type with double tenon and mortise; said first joint (30, 35) comprises: two hooks (35) placed at the end of the arm (13); two vertical slots (30) placed on the upright (12).

A jack, comprising: a top plate adapted to contact a load; a base plate positioned below the top plate; at least one actuator coupled perpendicularly between the base plate and the top plate; wherein the at least one actuator is operable to move the top plate between a lowered position and a raised position to thereby lower and raise the load; and, at least one locking assembly adapted to lock the top plate in the raised position.

A jack stand apparatus has a frame having a first portion and an outwardly extending second portion, a barrel affixed to the outwardly extending portion so as to have a generally vertical longitudinal axis, a jack screw threadedly received by the barrel, and a plurality of caster wheels removably affixed to the frame. The barrel has an outer end extending outwardly for a first distance from the first portion of the frame. The plurality of caster wheels support the frame for a second distance from a level of the bottom of the caster wheels. The first distance is no more than the second distance. A support head is affixed to an end of the jack screw opposite the barrel. The frame is invertible relative to the caster wheels such that in one position the barrel extends upwardly from the frame and a second position in which the barrel extends downwardly from the frame.