US 5,086,961 AGranted

Pipe severing method and apparatus

AssigneeKwik Snap Corporation

InventorsJames A. Angel, Gilbert G. Hagar, Michael H. Clement

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Abstract

A pipe severing device (1) and method utilizing a chain (13) having stress inducing wheels (19) efficiently and safely severs brittle materials including cast iron, vitreous clay, cement and asbestos pipe. The device includes an actuating handle (6) which pivots over a pipe support surface (3). Upon pivoting over the surface, holddown arms (7) attached to the actuating handle frictionally grasp a pipe. The handle may then pivot about a second point or remain rigid, in either case engaging a first limit switch (25) which actuates a hydraulic cylinder (35). The hydraulic cylinder tightens the chain causing the stress inducing wheels to create stress concentration points around the circumference of the pipe. Cracks propagate between stress concentration points, quickly severing the pipe. The pipe support surface includes resilient pads (5a,b) which further frictionally grasp the pipe.

Claims17

Dependent claims

A method of safely and quickly severing brittle pipe materials including cast iron, vitreous clay, cement, and asbestos comprising:

placing a pipe on a substantially horizontal surface of a mobile frame;
arranging a chain around the circumference of said pipe, said chain having a plurality of stress inducing wheels and a plurality of links having laterally protruding pins, said chain further having retaining spring means to bias said chain in a substantially circular position around said pipe;
connecting one end link of said chain to a cam actuated by a power unit and at least one other link of said chain to a chain cleat thereby tightly wrapping said pipe with said chain, said wheels touching said pipe at preselected locations;
pivoting an actuating handle about a pivot point, said handle having first and second holddown members attached thereto and positioned to frictionally engage the pipe on both sides of said chain, said actuating handle having a limit switch so that when said holddown members come into contact with the pipe to be severed, said limit switch actuates said hydraulic power unit, causing said chain to tighten about the pipe and induce stress concentration points around the circumference of said pipe at said selected locations and sever the pipe.

1 more element

A mobile pipe severing apparatus comprising:

a frame having a substantially horizontal pipe support surface;
pipe severing chain assembly carried by said frame including a chain, a chain cleat which grasps one end of said chain, and a chain drive actuated by a chain drive actuator, said chain having a plurality of stress inducing wheels mounted on a plurality of links, said links having laterally protruding pins, said chain drive including a power unit, said chain drive actuator comprising means for pivotally extending over said support surface in a manner allowing said actuator to actuate said chain drive;
and
a pipe stabilizing assembly attached to said chain drive actuator including at least one holddown member positioned to frictionally engage the pipe on both sides of said chain when said chain drive actuator is pivoted over said support surface, so that when said chain is drawn tight around the pipe said stress inducing wheels induce stress concentration points around the pipe and quickly sever the pipe.

1 more element

Dependencies are inferred from the claim text.