Patent GB-696388-A (GB)
Title: Improvements in and relating to shot and like blasting machines
IPC: B24C3/18
Filed: 1951-03-30
Abstract: 696,388. Blasting machines. JACKMAN & CO., Ltd., J. W., and NEVILLE, F. W. June 11, 1952 [March 30, 1951], No. 7380/51. Class 60. A blasting machine of the swinging arm and partition type has both the arm and a partition mounted on a common axis, the two being so mounted that they can be moved separately or together as required, means being provided whereby as the arm is rocked independently of the partition; the table on the arm inside the chamber can be rotated or oscillated while the table on the arm outside the chamber is not rotated. The blasting machine comprises a blasting chamber 8 enclosed save for an opening in the lower part of the front wall. An arm 10, having at each end a rotatable horizontal table 11, is mounted on a vertical shaft 9 resting in a thrust bearing 12. The upper part of the shaft 9 is surrounded by a sleeve 13 mounted in bearings 14, 15 and having connected to its lower end a partition 16 for closing the open part of the chamber. The partition can be locked in closed position by rods 17 operated by a handle 18 to pass through aligned holes in the frame and partition. A horizontal support 20 mounted on the sleeve 13 carries a geared electric motor 21 which drives through chain 23 and irreversible worm drive a crank 26 fitted with a connecting rod 27 pivotally connected to a link 29 secured on the top of the vertical shaft 9 so as to rock the arm 10. An arm 31 mounted below the support 20 so as to rotate with it has holes 32 through which bolts 33 pass when the partition 16 is locked by operation of the handle 18. When it is desired to turn the arm 10 so that one end, with its rotatable table, is swung out of the chamber and the other is swung in, the rocking movement of the arm is stopped by stopping the electric motor and the handle 18 is operated to release the locking means. The partition is then pulled from one edge to turn it, and thus the sleeve 13, support 20 and shaft 9. The tables 11 are mounted on members 34 pivoted at 35 to the arm 10; each member 34 has a pivoted bracket 36 provided with wheels 37 resting on a circular rail 38 which bears the weight of the tables to avoid undue strain on the arm 10; the pivots allow the wheels to accommodate themselves to irregularities on the supporting rail 38. The spindles of the tables 11 project below the arm 10, each having a rubber covered or like friction roller 39. Inside the chamber is a curved strip 40 mounted on a vertical spring arm 41, the strip being encountered by the roller 39 on the spindle of the table inside the chamber so that the table is rotated or oscillated as the arm 10 rocks to and fro. Means may be provided for releasing the pressure of the strip 40 when the arm 10 is being turned to reverse the positions of tables 11. In a modification, Fig. 7, a winding drum is mounted on the spindle of each table 11 below the arm 10 and on each drum are wound two wire ropes 43, 44 anchored to the drum and to the ends of the partition 16 at 45, 46 so that the table oscillates in time with the rocking arm 10 ; the drive from each winding drum to its corresponding table is transmitted through a clutch actuated by an operating lever, so that the tables are controlled individually and can be put in and out of gear as desired. Flexible sealing strips 49 of rubber or like material are provided around the edges of the partition 16 to prevent shot from escaping from the blasting chamber 8.