Pipe scraper

Claim 2

Apparatus for scraping the interior wall of a pipe, comprising carriage means having wheel means for engaging the wall of the pipe whereby said carriage means is movable longitudinally through the pipe, circumferentially segmented scraper means carried at only one end of said carriage means and disposed in a substantially complete circular arrangement around the interior wall of the pipe whereby substantially all of the circumference of the pipe wall will be scraped thereby, said scraper means being expandable against the pipe wall and retractable therefrom, whereby said apparatus may be employed to scrape the interior wall of a pipe when moved through the pipe in one direction.

Claim 3

The combination of claim 1, said scraper means comprising plural axially spaced staggered rows of scraper segments each fully engaged with the pipe wall at its outer end.

Claim 4

The combination of claim 1, said one end of said carriage means being at least substantially circular at its radially outer edge portion and being of a diameter only slightly smaller than the pipe diameter, said scraper means comprising plural scraper plates uniformly circularly hinged to the radially outer portion of said one end of said carriage means, said scraper means including body means linked to the scraper plates thereof and movable longitudinally of said carriage means in said one direction to draw the scraper plates inwardly to retracted positions and movable longitudinally of said carriage means in the opposite direction to push the scraper plates outwardly to expanded positions against the wall of a pipe within which said apparatus is disposed.

Claim 5

The combination of claim 3, including compression spring means for resiliently biasing each said scraper plate radially outward in contact with the wall of a pipe within which said apparatus is disposed.

Claim 6

The combination of claim 3, said body means being moved as described by pneumatic means.

Claim 7

The combination of claim 5, said pneumatic means comprising an air cylinder.

Claim 8

The combination of claim 3, said carriage means having a shaft axially supported therethrough, said body means being slidably disposed on said shaft.

Claim 9

The combination of claim 7, including connection means at each end of said shaft for use in drawing said apparatus through a pipe.

Claim 10

The combination of claim 3, each said scraper plate having an arcuate outer end adapted to uniformly engage the wall of the pipe to be scraped.

Claim 11

The combination of claim 9, said arcuate plate ends being sharpened.

Claim 12

The combination of claim 3, each said scraper plate having scraper blade means affixed to its outer end.

Claim 13

The combination of claim 11, said scraper blade means comprising thin flat plates.

Claim 14

The combination of claim 11, said scraper blade means comprising radially outwardly bowed bands affixed at their ends to the outer faces of said scraper plates and bowed toward the pipe therebetween.

Claim 15

Apparatus for scraping the interior wall of a pipe, comprising carriage means movable longitudinally through the pipe, circumferentially segmented circular scraper means carried by said carriage means at only one end thereof, said scraper means being expandable against the pipe wall and retractable therefrom, whereby said apparatus may be employed to scrape the interior wall of a pipe when moved through the pipe; said scraper means comprising plural scraper plates uniformly circularly hinged to said one end of said carriage means, said scraper means including body means linked to the scraper plates thereof and movable longitudinally of said carriage means in one direction to draw the scraper plates inwardly to retracted positions and movable longitudinally of said carriage means in the opposite direction to push the scraper plates outwardly to expanded positions against the wall of a pipe within which said apparatus is disposed, each said scraper plate having scraper blade means comprising radially outwardly bowed bands affixed to its outer end, said bowed bands being disposed in a first inner circumferential row and in a second outer circumferential row, the bands of said first and second rows being circumferentially offset whereby the entire inner pipe wall circumference is lapped by said bands.

Claim 16

Apparatus for scraping the interior wall of a pipe, comprising carriage means movable longitudinally through the pipe, circumferentially segmented circular scraper means carried by said carriage means at only one end thereof, said scraper means being expandable against the pipe wall and retractable therefrom, whereby said apparatus may be employed to scrape the interior wall of a pipe when moved through the pipe; said scraper means comprising plural scraper plates uniformly circularly hinged to said one end of said carriage means, said scraper means including body means linked to the scraper plates thereof and movable longitudinally of said carriage means in one direction to draw the scraper plates inwardly to retracted positions and movable longitudinally of said carriage means in the opposite direction to push the scraper plates outwardly to expanded positions against the wall of a pipe within which said apparatus is disposed, each said scraper plate having scraper blade means comprising radially outwardly bowed bands affixed to its outer end, said bowed bands being disposed in a first inner circumferential row and in a second outer circumferential row, the bands of said first and second rows being circumferentially offset whereby the entire inner pipe wall circumference is lapped by said bands.

Claim 17

The combination of claim 14, including means resiliently depressing the central portion of each band outwardly against the pipe wall whereby the bands conform to the pipe wall curvature when biased thereagainst.

Claim 18

The combination of claim 15, including means biasing said scraper plates resiliently outward against the wall of a pipe within which said apparatus is disposed.