Patent GB-338337-A (GB)
Title: Improvements in resurfacing machines for cylindrical sound records
Filed: 1929-10-31
Abstract: 338,337. Dictaphone Corporation, (Assignees of Feyrer, W. F.). Nov. 9, 1928, [Convention date]. Re-surfacing sound-records. - A machine for re-surfacing cylindrical sound-records comprises a record support, a traversing carriage carrying the re-surfacing tool, and feed mechanism for automatically advancing the tool at the end of each shaving cut. A mandrel shaft 15 carries a mandrel 16 upon which is mounted the cylindrical record 17 to be re-surfaced. A feed-screw 20 carries a pulley 25 connected by a belt 23 to a pulley 24, so that rotation of the mandrel shaft 15. through a belt 22 and pulley 21 causes rotation of the feed-screw 20. On a rod 19 is slidably mounted a carriage 18 which has a projecting arm 18a provided with a shoe 28a adapted to slide along a guide-rail 28. The carriage carries a flat spring 27 which normally holds a teed halfnut 26 in engagement with the feed-screw 20. A knife-bar 30, adjustably connected with a gaugebar 31 by a plate 32, carries a knife. 33 and is mounted on the carriage 18 and adapted to slide in a bore 38a. Before operation, the feed-nut 26 is placed adjacent to a recessed portion 29 of the feed-screw, while the knife-bar 33 is clear of the record 17, but the gauge-bar overlies the end of the record. The interconnected knife and gaugebars are then moved until the latter engages the record surface and the bars are locked in this adjusted position. The carriage 18 is then rooked upon the rod 19 by lifting the hand grip 46, so that the carriage 18 can be moved to the righthand side of the machine to the position for the commencement of a shaving cut. The rear end 37 of the knife-bar 30 is engaged by a helical cam 34 which is connected to a ratchet wheel 43 and a hand-grip disc 40 to form a face-cam unit. Rotation of the cam unit moves the knife-bar 30 towards the record 17 against the influence of a compression spring 38. A spiral spring 36 tends to turn the face-cam unit in the direction to bring the low point of the cam 34 opposite the end 37 of the knife-bar 30. To maintain the knifebar in an adjusted forward position, the ratchet wheel 43 is engaged by a pawl 41 held in engagement by a spiral spring 45 carried on a screw 44. Depression of a finger-piece 56, Fig. 8, disengages the pawl 41 and also a pawl 51 from the ratchet wheel 43 to allow retraction of the knife-bar 33 from the record 17. Near the left-hand end of the base-plate 12 is an actuator stud 50, the upper portion of which comprises a half-round portion. As the carriage 18 moves to the left, Fig. 3, at the end of a shaving cut, the stud 50 is engaged by a downwardly projecting finger 49 on one arm of a bell-crank lever 47 which is pivotally mounted below the carriage 18 on a screw 48 so to have a tilting as well as pivotal freedom of movement. An arm 51 of the lever 47 forms a feed pawl adapted to engage the bottom teeth of the ratchet wheel 43. A spiral spring 54 tends to press the bell-crank lever 47 upwardly against the under side of the carriage 18 and in an anti-clockwise. direction (as viewed in Fig. 3), which turning movement is limited by the engagement of a finger 55 with the rear of the carriage 18. As the carriage continues to move to the left, the reaction between the finger 49 and the stud 50 turns the bell crank 47 in a clockwise direction to rotate the face-cam unit and adjust the knifebar towards the record for making the next shaving cut, after the carriage has been traversed by hand to the right-hand side of the machine, as described above.