Hydraulic hand jack
AssigneeAuto Specialties Manufacturing Company
InventorR. Harlan Nehrig
Life of this patent
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Abstract
A hydraulic jack is disclosed, of the type comprising a ram having a head portion reciprocable in a cylinder between two cylinder ends, and sealing means carried on the ram head portion to provide a substantially fluid-tight seal between the ram and the cylinder interior surface. In this jack, an open sided pressure relief trough is formed in the interior surface of the cylinder adjacent one end to permit the flow of fluid past the sealing means when the head portion is located substantially adjacent the cylinder end and relief trough. Fluid bleeding action past the relief trough thus prevents forcing the ram head and sealing means against the cylinder end. When the jack is so constructed, the sealing means can include an elastomeric seal cup member which will not be damaged by its travel past the trough.
Claims13
In a hydraulic jack comprising a cylinder having two ends and an interior surface, a ram having a head portion reciprocable in the cylinder between the cylinder ends and a rod portion partially extending through one cylinder end to exert a jacking action as the ram head portion moves toward that cylinder end, sealing means carried on the ram head portion to provide a substantially fluid-tight seal between the ram and the cylinder interior surface, the improvement comprising opensided trough means in the interior surface of the cylinder to permit the flow of fluid past the sealing means when the head portion is located substantially adjacent the one cylinder end so as to prevent forcing the ram head and sealing means against the cylinder end and a cylinder cap affixed at said one cylinder end extending from that cylinder end axially along said cylinder over that portion of the cylinder in which said trough means is disposed so as to strengthen that portion of the cylinder.
A hydraulic jack comprising a cylinder having two ends and an interior surface, a ram having a head portion reciprocable in the cylinder between the cylinder ends, sealing means carried on the ram head portion to provide a substantially fluid-tight seal between the ram head portion and the cylinder interior surface, and open-sided trough means cold formed in the interior surface of the cylinder to permit the flow of fluid past the sealing means when the ram head portion is located substantially adjacent the trough means so as to prevent forcing the ram head portion and sealing means against one cylinder end and a cylinder cap affixed at said one cylinder end and extending from that cylinder end axially along said cylinder over that portion of the cylinder in which said trough means is disposed so as to strengthen that portion of the cylinder.
Dependencies are inferred from the claim text.