Multi-section hydraulic ram

Claim 2

A fluid operated extensible and retractable ram comprising a base section, a mid-section and an interior rod section arranged in telescopic interfitting relation, an annular piston on the mid-section adapted to reciprocate in the bore of the base section, an annular piston on the rod section adapted to reciprocate in the bore of the mid-section, a closure element on the end of the rod section distant from the rod section piston, a central fluid inlet tube fixed with relation to the base section and extending axially through the bores of said annular pistons and within the base section to a point close to the closure element when the ram is in a fully retracted condition, said annular mid-section piston having its bore in fluid sealing engagement with the exterior surface of said tube, the annular rod section piston having its bore spaced from said tube to provide a passageway for fluid therebetween, said tube delivering working fluid to the extension side of the rod section piston and to the face of said closure element, fluid passage means for delivering fluid to the retraction side of the rod section piston, and separate fluid passage means for delivering fluid to the extension and retraction sides of the mid-section piston, thereby enabling the mid-section and rod section to be independently and individually operated.

Claim 3

The structure as defined in claim 1, and said tube having a length at least as great as the full stroke of the mid-section piston so that such piston always remains engaged with said tube.

Claim 4

The structure as defined in claim 2, and a closure cap for the rear end of the base section, and the rear end of said tube anchored to the closure cap and having its bore opening therethrough for the reception of fluid.

Claim 5

A fluid operated extensible and retractable ram comprising a base section, a mid-section and an interior rod section arranged in telescopic interfitting relation, an annular piston on the mid-section adapted to reciprocate in the bore of the base section, an annular piston on the rod section adapted to reciprocate in the bore of the mid-section, a closure element on the end of the rod section distant from the rod section piston, a central fluid inlet tube fixed with relation to the base seCtion and extending axially through the bores of said annular pistons and within the base section to a point close to the closure element when the ram is in a fully retracted condition, the annular rod section piston having its bore spaced from said tube to provide a passageway for fluid therebetween, said tube delivering working fluid to the extension side of the rod section piston and to the face of said closure element, fluid passage means comprising a fitting connected in the side wall of said mid-section near the forward end thereof and forwardly of the base section when the ram is fully retracted for delivering fluid to the retraction side of the rod section piston, and separate fluid passage means for delivering fluid to the extension and retraction sides of the mid-section piston, thereby enabling the mid-section and rod section to be independently and individually operated.

Claim 6

A fluid operated extensible and retractable ram comprising a base section, a mid-section and an interior rod section arranged in telescopic interfitting relation, an annular piston on the mid-section adapted to reciprocate in the bore of the base section, an annular piston on the rod section adapted to reciprocate in the bore of the mid-section, a closure element on the end of the rod section distant from the rod section piston, a central fluid inlet tube fixed with relation to the base seCtion and extending axially through the bores of said annular pistons and within the base section to a point close to the closure element when the ram is in a fully retracted condition, the annular rod section piston having its bore spaced from said tube to provide a passageway for fluid therebetween, said tube delivering working fluid to the extension side of the rod section piston and to the face of said closure element, fluid passage means comprising a fitting connected in the side wall of said mid-section near the forward end thereof and forwardly of the base section when the ram is fully retracted for delivering fluid to the retraction side of the rod section piston, and separate fluid passage means for delivering fluid to the extension and retraction sides of the mid-section piston, thereby enabling the mid-section and rod section to be independently and individually operated.

Claim 7

The structure as defined in claim 4, and said separate fluid passage means comprising a pair of fittings connected in the side wall of the base section near opposite ends of the base section.

Claim 8

The structure as defined in claim 1, and said base, mid and rod sections of the ram being in substantially concentric spaced relation to provide fluid chambers therebetween, and said mid-section and rod section pistons having their peripheries extending radially beyond the tube members which constitute the mid-section and the rod section of the ram.

Claim 9

The structure as defined in claim 6, and spacer sleeves disposed within the bores of the base section and mid-section and engageable by the pistons of the mid-section and rod section to positively limit retraction and extension thereof.

Claim 10

The structure as defined in claim 1, and said interior rod section including a tubular body, said rod section piston secured to the rear end of the tubular body and extending radially inwardly and outwardly thereof.

Claim 11

The structure as defined in claim 1, and the total effective extension face of the rod section piston being a divided face and comprising the sum of the areas of the rear side of the rod section piston and that area of the the closure element which is encompassed by a projection of the bore of the rod section piston.