Patent GB-662384-A (GB)
Title: Improvements in or relating to continuous work blasting machines
IPC: B24C3/26
Filed: 1949-08-03
Abstract: 662,384. Rumbles; sand-blast. PANGBORN CORPORATION. Aug. 3, 1949 [Aug. 3, 1948], No. 20235/49. Class 60 A shake-out drum, adapted to form an end of a blasting mill having a work tumbling drum and means associated therewith for propelling thereinto a blasting medium for acting upon the surface of work articles travelling along the bottom of said work tumbling drum, comprises a cylindrical shell adapted to be rotated about its longitudinal axis and having a perforated screening wall portion, a helical, or spiral blade of at least one convolution secured co-axially within said shell and having its outer edge in juxtaposition to the inside surface of said shell, said blade being adopted upon rotation of the shell to move said articles axially of the shell over the screening portion, said blade having a width substantially equal to the radius of the shell and forming a baffle for arresting and precipitating flying particles of detritus and the blasting medium. A continuous blasting machine has axially spaced tumbling barrels 12, endless conveyer type flexible bridging means 13 moving with the barrels and spanning the gaps therebetween and blasting wheels 11 located at the gaps and propelling blasting streams of metallic grit or shot into the barrels, as described in Specification 646,656. The barrels 12 are supported and driven by rolls 15; the bridging means 13 of the chain and slat type are supported and driven by sprockets 15a; a driving motor 15b is provided. Work is fed into the machine by chute 12a, the first barrel has a corner filler 12b to prevent piling of the work adjacent the inlet and the barrels are provided internally with inclined cleats to aid in tumbling the work and advancing it through the machine. An end member 14, for arresting and precipitating flying abrasive and detritus, effecting separation of the abrasive and detritus from the treated articles and delivery of the latter apart from the abrasive and detritus, is rotatably mounted on driving rolls 15 and contains a helix 16 having its turns separated sufficiently to allow for the free passage therebetween of the largest work pieces to be treated. Part of the member 14 has work upsetting cleats 17 between the turns of the helix to tumble the work and ensure the release of abrasive and loose detritus trapped in pockets thereof; the cleated portion is followed by an uncleated portion in which the work, abrasive and detritus slide along the lower portions of the member 14 as it is forced longitudinally thereof. The abrasive and detritus pass through perforations 22 into a hopper from which it is removed for classifying and for recirculation of the blasting medium. The articles are delivered by chute 26 into tote-box 27. The member 14 comprises an outer section and two inner sections 23, 23a; section 23 is subject to maximum wear and can be replaced; section 23a is formed as a relatively light-weight liner extending beyond the outer section 14 and the machine housing 10. The helix preferably has 2# turns and winds about a central core 21. The parts may be secured together by tack welding. The receiving end of the member 14 extends a substantial distance beyond the adjacent end of helix 16 so that as the radial edge 25 of the helix passes into the body of castings those which may be pushed backwardly are not forced backwardly against the bridging means 13; the receiving threshold 24 thus provided ensures smooth feeding of the workpieces toward and into the helix 16, and as the threshold is not cleated rough tumbling of the work against the edge 25 of the helix is avoided and wear is reduced at this point. The edge 25 is preferably spaced from the drum end by a distance approximately half the greatest dimension of articles to be treated so that if an article should balance on the edge 25 and be carried upwardly thereby, it would not jam against the stationary housing 11a which accommodates the blasting wheel 11.