Piping travelling apparatus

• US 4,770,105 A
• Filed: 08/04/1986
• Issued: 09/13/1988
• Est. Priority Date: 08/07/1985
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Tokyo Gas Company Limited
• Original Assignee: Hitachi, Ltd., Tokyo Gas Company Limited
• Inventors: Kurita, Shinichi, Sakamoto, Kiyoshi, Takagi, Atsushi, Sato, Chikara, Watahiki, Seishi, Sakuma, Yasuzi
• Primary Examiner(s): Noland, Tom
• Application Number:
  US06/892,285
• Time in Patent Office: 771 Days
• Field of Search: 104/138.2, 73/866.5, 73/865.8, 175/73, 175/76, 175/94
• US Class Current: 104/138.2
• CPC Class Codes: F16L 2101/30 Inspecting, measuring or testing
• CPC Class Codes: F16L 55/30 of the propulsion means, e.g. towed by cables
• CPC Class Codes: F16L 55/32 being self-contained
• CPC Class Codes: G21C 17/017 Inspection or maintenance of pipe-lines or tubes in nuclear installations
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A piping travelling apparatus having a plurality of continuous treads driven by motors through transmission gearing. The continuous treads are mounted to a frame and spaced apart a predetermined distance peripherally of the inner wall surface of the piping. At least one of the continuous treads is kept in contact with the inner wall surface of the piping no matter what the posture of the apparatus may be, so that the apparatus can travel without any trouble even if its posture undergoes a change when it moves along elevations and depressions on the inner wall surface of the piping or negotiates the boundary between different levels of the inner wall surface or bends of the piping. The apparatus enables a travel through piping of relatively small diameter having vertical or steeply slanted pipes to be made without any trouble.

Claims

1. A piping traveling apparatus, comprising:

a frame;

a plurality of continuous treads mounted for rotation on said frame so that at least a portion of each tread is disposed outside said frame to drive the frame as the treads rotate in contact with an inner wall surface of the piping;

drive means including at least one motor and transmission gearing coupled between said motor and said continuous treads for driving said treads in rotation;

continuous tread biasing means for forcing said plurality of continuous treads outwardly of said frame so as to be pressed into contact with the inner wall surface of the piping;

control means for remotely controlling said continuous tread biasing means so as to selectively vary the outward force applied to said continuous treads to vary the contact pressure between said continuous treads and the inner wall surface of the piping as said apparatus;

wherein said continuous tread biasing means comprises spring holder means mounted on said frame and means including at least one coil spring supported by said spring holder means for biasing said continuous treads, said coil spring being formed of a shape memory alloy, and wherein said control means comprises heating means for selectively heating said coil spring to control the biasing force thereof.

2. An apparatus according to claim 1, wherein pairs of continuous treads are mounted in opposing relationship for outward movement in opposite directions, and wherein said continuous tread biasing means is disposed between the treads of at least one pair so as to effect said outward movement thereof in a controlled manner under control of said control means.

3. A piping traveling apparatus, comprising:

a frame;

a plurality of continuous treads mounted for rotation on said frame so that at least a portion of each tread is disposed outside said frame to drive the frame as the treads rotate in contact with an inner wall surface of the piping;

drive means including at least one motor and transmission gearing coupled between said motor and said continuous treads for driving said treads in rotation; and

continuous tread biasing means for forcing said plurality of continuous treads outwardly of said frame so as to be pressed into contact with the inner wall surface of the piping;

wherein pairs of continuous treads are mounted in opposing relationship for outward movement in opposite directions, and wherein said continuous tread biasing means is disposed between the treads of at least one pair of continuous treads, so as to effect said outward movement thereof in a controlled manner under control of a control means;

said continuous tread biasing means comprising a plurality of pairs of parallel links and a plurality of plate springs, each pair of said parallel links pivotally connecting each of the continuous treads with the frame for switching the tread in the tread rotating plane, and each pair of said plate springs connecting the diametrically opposed continuous treads of a pair with each other for forcing the treads against the inner wall surface of the piping, whereby the apparatus can travel back and forth through the piping with the continuous tread forced against the inner wall surface of the piping by means of said continuous tread biasing means.