US 6,671,966 B2Granted

Hydraulic and pneumatic actuated cutting apparatus

AssigneesCalvin R. MacKay, John E. Lewis

InventorJohn B. Lewis

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Abstract

A hydraulically and/or pneumatically actuated cutting tool is provided having a housing with a piston assembly slidably disposed between a fluid inlet and a fluid outlet. The piston assembly comprises a seal which is operable between two positions. In a first position the seal produces a substantially water-tight seal between the piston and the interior surface of the housing. As a result, fluid entering the chamber through the fluid inlet advances the piston assembly toward the fluid outlet. In a second position a gap is formed between the seal and the interior surface of the housing such that fluid communication is established between the fluid inlet and the fluid outlet. As the fluid is removed from the housing through the fluid outlet, a spring biases the piston assembly back to its original resting position.

Claims22

Dependent claims

A cutting apparatus comprising:

a housing having an interior surface bounding a chamber, the chamber communicating with a fluid inlet and a fluid outlet;
a piston assembly slidably disposed within the chamber between the fluid inlet and the fluid outlet, the piston assembly being configured such that as fluid enters into the chamber through the fluid inlet, pressure from the fluid advances the piston assembly toward the fluid outlet, the piston assembly comprising:
a piston;
and
means for forming a substantially water-tight seal between the piston and the interior surface of the housing when pressure from the fluid is applied to the piston and for enabling fluid to pass between the piston and the interior surface of the housing as pressure from the fluid is decreased;
a blade sheath connected to the housing;
a cutting blade slidably disposed relative to the blade sheath;
a piston rod having a first end connected to the piston assembly and an opposing second end connected to the cutting blade;
and
means for automatically returning the piston assembly toward the fluid inlet when the fluid is removed from within the housing through the fluid outlet.

7 more elements

A cutting apparatus comprising:

a housing having an interior surface bounding a chamber, the chamber communicating with a fluid inlet at a first end and a fluid outlet at an opposing second end;
a piston assembly slidably disposed within the chamber between the fluid inlet and the fluid outlet, the piston assembly being configured such that as fluid enters into the chamber through the fluid inlet, pressure from the fluid advances the piston assembly toward the fluid outlet, the piston assembly comprising:
a piston;
and
a seal disposed adjacent to the piston, the seal being operable between a first position wherein the seal produces a substantially water-tight seal between the piston and the interior surface of the housing and a second position wherein a gap is formed between the seal and the interior surface of the housing such that fluid communication is established between the fluid inlet and the fluid outlet;
a blade sheath connected to the housing;
a cutting blade slidably disposed relative to the blade sheath;
a piston rod having a first end connected to the piston assembly and an opposing second end connected to the cutting blade;
and
a spring disposed between the housing and the piston assembly so as to bias the piston assembly toward the fluid inlet.

7 more elements

Dependencies are inferred from the claim text.