Reciprocable load resisting device

Abstract

A load resisting device for use in an exercise machine which includes a cylinder, a piston which is movable in a first direction inside the cylinder against a force generated by air pressure in the cylinder, and an O-ring seal, mounted to the piston, which provides a seal between the piston and the cylinder, when the piston is moved in a first direction, and which allows air to bypass the O-ring when the piston is moved in a second direction which is opposite to the first direction.

1 . A reciprocable load-resisting device which includes a cylinder with an inner closed end and an outer, open end, a piston which is reciprocably located inside the cylinder thereby defining a volume of variable size inside the cylinder between the inner closed end of the cylinder and a first side of the piston, a rod which is fixed to the piston and which extends from the cylinder through the outer, open end, a first mounting formation on the cylinder, a second mounting formation on the rod, a one-way valve which is associated with the piston and which opens to allow fluid to flow into the volume when the piston is withdrawn from the cylinder and which closes when the piston is moved into the cylinder so that the piston causes fluid inside the volume to be pressurised, an outlet from the volume through which fluid can flow when the volume is pressurised, and a control mechanism which is adjustable to control the rate at which fluid can flow from the volume.  
   
   
       2 . A load-resisting device according to  claim 1  wherein the outlet returns fluid which flows from the volume to the cylinder on a second side of the piston.  
   
   
       3 . A load-resisting device according to  claim 1  which includes a cap which is fixed to the outer, open end of the cylinder and which includes an opening through which the piston rod extends.  
   
   
       4 . A load-resisting device according to  claim 1  which includes a bypass conduit which extends from the volume to a portion of the cylinder between the second side of the piston and wherein the outer end of the cylinder and the control mechanism is engaged with the bypass conduit.  
   
   
       5 . A load-resisting device according to  claim 1  wherein the control mechanism is mounted to the piston so that fluid can flow through the piston, or bypass the piston, when it flows from the volume to the cylinder between the outer, open end and the second side of the piston.  
   
   
       6 . A load-resisting device according to  claim 5  wherein the control mechanism may be adjustable to allow fluid to flow, inside the cylinder, from the first side of the piston to the second side.  
   
   
       7 . A load-resisting device according to  claim 1  wherein the one-way valve is formed by an O-ring which is mounted to the piston and which is moved from a sealing position, when the piston is moved into the cylinder, to a non-sealing position, when the piston is withdrawn from the cylinder.  
   
   
       8 . A load-resisting device for use in an exercise machine which includes a cylinder, a piston which is movable in a first direction inside the cylinder against a force generated by air pressure in the cylinder, and an O-ring seal, mounted to the piston, which provides a seal between the piston and the cylinder, when the piston is moved in a first direction, and which allows air to bypass the O-ring when the piston is moved in a second direction which is opposite to the first direction.