Patent GB-1191154-A (GB)
Title: Machine and Method for Surface Treatment of Large Articles
IPC: B24C3/08
Filed: 1967-06-05
Abstract: 1,191,154. Blasting. WHEELABRATOR CORP. 5 June, 1967 [27 July, 1966], No. 25861/67. Heading B3D. A method for surface treatment of articles by the engagement of the surfaces with particulate treating material includes the steps of- (i) providing a rigid elongate open cage having a continuous passage extending therethrough from an entrance at one end to an exit at the other; (ii) turning said cage for rotational movement about its axis; (iii) inserting articles endwise into the passage through the entrance end whereby the articles become aligned in end-to-end relationship within said passage for displacement of the aligned articles lengthwise through said passage from the entrance end towards the exit end responsive to said insertion of the article; and (iv) throwing particulate treating material on to an intermediate portion of said cage between the entrance end and the exit end while the cage is being rotated thereby uniformly to expose the surfaces of the articles within the cage to the particulate treating material. A rigid elongate open cage 20, Fig. 1, comprises circumferentially spaced bars 30 fixed at their ends to rings 32, the bars defining a passage corresponding to the cross-section of castings 24 to be treated. The leading end portions 34 of the bars are tapered outwardly to the ring member to define an entrance portion 36. The bars are preferably of tubular or rectangular cross-section, for minimum contact with the casting and preferably receive the casting loosely so that during the rotation spaces occur between bars and casting. Preferably three to six bars are used. The cage may be a single length, but is preferably interconnected lengths A, B, C. The rings 32 and intermediate rings 46 are supported by pairs of rollers, the end pairs 40 being driven to rotate the cage, the other pairs 50 being idlers. Instead of, or in addition to, the rings 32, the cage may carry ring gears (60) meshing with driven gears (62). A portion of the cage is enclosed by a blast cabinet 26 of length equal to the length of five to eight castings with entrance and exit openings 64, 66 with associated vestibules 26<SP>1</SP> to minimize ricochet. The blast cabinet has centrifugal blasting wheels 70, e.g. as in U.S.A. Specification 2,819,562, throwing particulate treating material. Spent material falls into a trough 75 and is conveyed by a screw 76, lateral screw and elevator (78) to a separator (80), re-usable material being returned to a hopper (72) for re-use. At least the portion of the cage located within the cabinet is made of metal having high erosion resistance. In cleaning cylinder heads, the cage is rotated at about 15 r.p.m. and castings displaced through the cage at 200-1000 per hour. Rotation of the cage may be stopped in a predetermined position and for a time sufficient to insert a casting. Preferably, however, the cage is continuously rotated, and means employed for proper orientation of the castings for periodic insertion into the cage. For example, a feed cage 90, Fig. 4, dimensioned to receive a single casting, is mounted on rollers 92, 94 in alignment with the main cage 20; rotation of the feed cage 90 is stopped for a time sufficient for insertion of a casting therein, while the main cage 20 continues to rotate; the loaded fuel cage 90 is then rotated until its speed is synchronized with that of the main cage 20 whereafter the casting is displaced endwise from the feed cage 90 into the main cage 20. The feed cage comprises bars 96 joined to rings 98, the bars at the entry end tapering outwardly at 100 to provide a feed opening 102; one bar has an abutment 104. The rollers 92, 94 are carried by shafts 106, (108) connected by gears 114, 116 to a driving motor 118. The upper end of a cage stop arm (120) can be rocked into and out of the path of the abutment 104 to stop rotation of the cage when it is correctly orientated to receive a casting. The casting mounted on a slat conveyer 134 in endwise alignment with the feed cage is inserted into the cage by pusher means comprising a ram 124 suspended from a carriage 128 supported on rollers 130 for movement by the piston of a fluid cylinder 132. Limit switches 136, 140, 142 are actuated by a trip 138 on the carriage; a limit switch (122) is associated with the stop arm (120). In operation, the feed cage 90 is rotated by the rollers 92, 94 until stopped in oriented position by engagement of stop arm (120) by the abutment 104, the rollers continuing to rotate. Limit switch (122) is actuated, causing the carriage to move from retracted position to a first position whereby the casting on the slat conveyer is pushed into the feed cage. When the switch 136 is actuated, the stop arm (120) is withdrawn, so that the loaded cage is rotated by the rollers 92, 94 to a speed differing slightly from that of the main cage, and preferably a slightly higher speed; an arm is extended lengthwise fiom one cage to engage an abutment of the other cage to couple the cages. The carriage then moves to its second position whereby the casting in the feed cage is pushed into the main cage; this displaces all the castings in the main cage by the length of a casting, the leading casting being displaced from the main cage on to a conveyer or shoot 144. When switch 140 is made the carriage is returned to retracted position. When switch 142 is made the stop arm (120) is rocked into operative position. In a modification, Fig. 9, four feed cages 90 are mounted for rotation in a turret 150 rotatable about its axis 152 and aligned with the end of the main cage to provide two stations about 180 degrees apart, viz. a feed station aligned with the main cage and a loading station aligned with a conveyer on which castings are brought to the machine. Means, e.g. a stop arm, are provided for arresting rotation of the cages while in the loading station so that a ram can be operated by an hydraulic cylinder to push a casting on the conveyer into the feed cage at that station. When loading is completed, the turret is turned through 90 degrees to bring another empty feed cage into the loading station while a support roller 162 of the loaded feed cage engages a driving endless belt or chain 154 to rotate the cage. By the time the loaded feed cage has arrived at the feed station, by further indexing of the turret, the loaded cage is up to speed and oriented with the main cage. A second ram operated by an hydraulic cylinder pushes the casting from the feed cage into the main cage. While it is possible merely to let the leading casting issue from the exit end of the main cage, it is often desirable to receive it in a cage synchronized with the main cage to overcome the centrifugal force of the casting; for this purpose use can be made of a turret similar to that described above and having a receiving station in alignment with the main cage and an unloading station. Means may be provided for effecting endwise displacement of the turret a short distance away from the end of the main cage. In a further modification, Fig. 11, a conveyer 200 for castings 24 comprises endless belts 202, 204 driven by a motor 216 and having cleats 218 longitudinally spaced by a distance proportional to the rotation of the main cage 20, the belts being longitudinally displaced by an amount corresponding to the spaced relationship between the cleats during each rotation of the main cage or a predetermined multiple thereof. Attached to the end of the main cage so as to rotate therewith is a loading cage 220 having an opening 224 extending therethrough in alignment with the opening through the main cage. The cage 220 has a slot 226 so dimensioned as to allow a casting 24 to pass therethrough. The length of the cage 220 is greater than the spacing of the belts 202, 204. The cage 220 has a pair of arms 234 having a lateral spacing slightly greater than that of the belts 202, 204, and extending outwardly beyond the cage by an amount greater than the width of the castings, so that the arms lift a casting from the end portion of the belts. As the cage continues to rotate the casting slides through the slot 226 into the loading cage. When the loading cage has rotated through about 90 degrees from the loading position a ram 236 pushes the casting from the loading cage 220 into the main cage 20. A similar unloading cage 240 is provided at the exit end of the main cage.