Exercise systems
An adjustable weight lifting bench includes a frame, a seat pad, and a back pad. The back pad is pivotably coupled to the frame about a first pivot axis and angularly adjustable between a plurality of user-selectable incline and decline positions. A hydraulic mechanism supports the back pad in the incline and decline positions. A movable operating lever operably coupled to the hydraulic mechanism operates to change the mechanism between an activated condition in which the back pad is movable and a deactivated condition in which the back pad locks into a selected one of the positions. When the mechanism is in activated condition, applying pressure against the back pad the lowers the back pad and removing the pressure raises the back pad. In one embodiment, the mechanism automatically raises the back pad when the pressure is removed and the mechanism is in the deactivated condition.
1. A hydraulic cylinder assembly comprising:
a hydraulic cylinder containing a hydraulic fluid;
an accumulator in fluid communication with the hydraulic cylinder, the accumulator containing a pressurized compressible fluid; and
a flow control valve assembly interposed in a flow path between the hydraulic cylinder and the accumulator, the flow control valve configured and operable to control flow of the hydraulic fluid exchanged between the hydraulic cylinder and accumulator;
the flow control valve including an axially reciprocating piston defining a flow control orifice and an axially movable plunger having an operating end and an opposing working end, the working end being received in the flow control orifice and positionable between a first axial position and a second axial position relative to the flow control orifice;
an operating lever pivotably coupled to the flow control valve, the operating lever movable to control movement of the working end of plunger between the first and second axial positions;
wherein the working end of the plunger defines a first flow area when the plunger is in the first axial position and a second flow area smaller than the first flow area when the plunger is in the second axial position.
2. The assembly of claim 1 , further comprising a toggle cam coupled to the operating lever and defining a cam surface which acts on a cam follower defined by the plunger, the toggle cam pivotably movable via the operating lever to move the working end of the plunger between the first and second axial positions.
3. The assembly of claim 2 , wherein the toggle cam has an elongated body defining a first end pivotably coupled to the flow control valve and a second end pivotably coupled to the operating lever.
4. The assembly of claim 3 , wherein the toggle cam translates linear movement of the operating lever to rotary motion of the toggle cam.
5. The assembly of claim 3 , wherein a pivot point defined by the first end of the toggle cam is located eccentrically from a centerline of the toggle cam adjacent to the cam surface.
6. The assembly of claim 2 , wherein the cam follower is defined by the operating end of the plunger and protrudes downwards from a body of the flow control valve.
7. The assembly of claim 2 , wherein the cam follower is biased by a spring to maintain engagement with the cam surface.
8. The assembly of claim 1 , further comprising a check valve disposed in flow conduit circuit through the flow control valve separate from the flow path between the hydraulic cylinder and the accumulator.
9. The assembly of claim 8 , wherein the check valve is configured to permit one-way flow from the accumulator to the hydraulic cylinder.
10. The assembly of claim 1 , wherein the accumulator comprises an axially slideable second piston.
11. The assembly of claim 10 , wherein the second piston defines an air to oil interface between oil in the hydraulic cylinder and air in the accumulator.
12. The assembly of claim 11 , wherein the second piston shifts axial position within the accumulator in response to movement of the piston in the hydraulic cylinder.
13. The assembly of claim 12 , wherein oil is exchanged between the hydraulic cylinder and accumulator upon movement of the piston in the hydraulic cylinder.
14. The assembly of claim 11 , wherein the air in the accumulator has a precharged pressure.