Lifting machine having a permanent reciprocating motion

Claim 2

A lifting machine for imparting a permanent reciprocating motion to a load between an extreme upper position and an extreme lower position, comprising a balancing counterweight, flexible connecting means for connecting the load to the counterweight, the load, the connecting means and the counterweight constituting an assembly, a fluid motor, drive means for drivingly connecting the fluid-motor to said assembly for imparting said motion to said assembly, a hydraulic variable-flow pump connected to the fluid motor for supplying actuating fluid to the fluid motor, and to control device associated with the pump for causing the pump to operate in accordance with a predetermined law by repeated reversals of the flow of actuating fluid delivered by the pump to the fluid motor, the pump comprising a movable regulating element whose position is proportional to the output flow of the pump and consequently to the speed of the fluid motor, the control device comprising actuating means connected to be driven by the drive means, and an over-center device connecting the actuating means to the regulating element, the actuating means being operative at said extreme upper position and said extreme lower position of the load, said actuating means comprising two shafts connected to be driven in rotation by the drive means and two trip means respectively connected to the two shafts to be driven by the two shafts, whereby the over-center device comprises a pivotal input lever pivotable between two extreme positions respectively corresponding to said extreme upper position and said extreme lower position of the load, the two trip means being respectively capable of coming in contact with the pivotal input lever in said two extreme positions of the pivotal input lever.

Claim 3

A lifting machine as claimed in claim 1, wherein the actuating means comprise adjusting means capable of independently adjusting said extreme upper position and extreme lower position of the load undergoing reciprocating motion, the shafts are parallel to each other and located on each side of the pivotal inlet lever which is pivotable in a plane perpendicular to the two shafts, the adjusting means comprise means for varying the positions of the trip means with respect to the shafts and consequently the positions in which the trip means come in contact with the pivotal inlet lever.

Claim 4

A lifting machine as claimed in claim 2, wherein each trip means comprises a second lever mounted on the corresponding shaft to be rotated by the corresponding shaft, the second lever being pivotable about an axis intermediate the ends of the second lever and parallel to the corresponding shaft, a roller rotatably mounted on one end of the second lever and a trip member mounted at the opposite end of the second lever and the means for varying the position of the trip means comprise for each shaft, means defining a frustoconical face which is coaxial with thE corresponding shaft and prevented from rotating and axially movable, resiliently yieldable means for biasing the second lever to cause the roller to bear against the frustoconical face, and means for adjusting the position of the frustoconical face axially of the corresponding shaft so as to vary the distance of the trip member from the axis of the corresponding shaft.

Claim 5

A lifting machine for imparting a permanent reciprocating motion to a load between an extreme upper position and an extreme lower position, comprising a balancing counterweight, flexible connecting means for connecting the load to the counterweight, the load, the connecting means and the counterweight constituting an assembly, a fluid motor, drive means for drivingly connecting the fluid-motor to said assembly for imparting said motion to said assembly, a hydraulic variable-flow pump connected to the fluid motor for supplying actuating fluid to the fluid motor, and a control device associated with the pump for causing the pump to operate in accordance with a predetermined law by repeated reversals of the flow of actuating fluid delivered by the pump to the fluid motor, the pump comprising a movable regulating element whose position is proportional to the output flow of the pump and consequently to the speed of the fluid motor, the control device comprising actuating means connected to be driven by the drive means, and an over-center device connecting the actuating means to the regulating element, the actuating means being operative at said extreme upper position and said extreme lower position of the load, said over-center device being connected to said regulating element through transmission means comprising at least two cam mechanisms whose movements are controlled by those of said actuating means, each of the cam mechanisms controlling one of the directions of flow of the fluid in the circuit of said pump by acting on said regulating element, each of said cam mechanisms comprising a cam which is rotatably mounted, a follower roller, and a telescopic connection connecting the roller to said regulating element, the telescopic connection being capable of being selectively rendered rigid as a function of the direction of motion of said load.

Claim 6

A lifting machine for imparting a permanent reciprocating motion to a load between an extreme upper position and an extreme lower position, comprising a balancing counterweight, flexible connecting means for connecting the load to the counterweight, the load, the connecting means and the counterweight constituting an assembly, a fluid motor, drive means for drivingly connecting the fluid-motor to said assembly for imparting said motion to said assembly, a hydraulic variable-flow pump connected to the fluid motor for supplying actuating fluid to the fluid motor, and a control device associated with the pump for causing the pump to operate in accordance with a predetermined law by repeated reversals of the flow of actuating fluid delivered by the pump to the fluid motor, the pump comprising a movable regulating element whose position is proportional to the output flow of the pump and consequently to the speed of the fluid motor, the control device comprising actuating means connected to be driven by the drive means, and an over-center device connecting the actuating means to the regulating element, the actuating means being operative at said extreme upper position and said extreme lower position of the load, said over-center device being connected to said regulating element through transmission means comprising at least two cam mechanisms whose movements are controlled by those of said actuating means, each of the cam mechanisms controlling one of the directions of flow of the fluid in the circuit of said pump by acting on said regulating element, each of said cam mechanisms comprising a cam which is rotatably mounted, a follower roller, and a telescopic connection connecting the roller to said regulating element, the telescopic connection being capable of being selectively rendered rigid as a function of the direction of motion of said load.

Claim 7

A lifting machine as claimed in claim 4, wherein each telescopic connection comprises a cylinder device having a body and a rod which are respectively connected to said regulating element and said roller.

Claim 8

A lifting machine as claimed in claim 5, comprising a spool valve connected to the cylinder device and controlled by said over-center device and adapted to put the cylinder device selectively under pressure in accordance with the position of said load in the course of its reciprocating motion.

Claim 9

A lifting machine as claimed in claim 6, wherein said regulating element comprises a lever pivoted to the body of said pump and capable of pivoting between two extreme positions of maximum positive flow and maximum negative flow in passing through an intermediate position, a regulating mechanism connecting said rods of the cylinder devices to said lever whereby it is possible to modify the leverage of said lever.

Claim 10

A lifting machine as claimed in claim 6, wherein each cylinder device comprises means for regulating its degree of extension so as to determine, upon each reversal of motion of said load, a given starting speed through the medium of said regulating element.