Patent GB-238522-A (GB)
Title: Improvements in phonographs such as dictating machines
Filed: 1925-06-22
Abstract: 238,522. Dictaphone Corporation, (Assignees of Lucarelle, J. M., and Renholdt, J. E.). Aug. 13, 1924, [Convention date]. Returning sound-box to starting point; toolarms and mountings.-In phonographs, such as dictating machines, constructed to permit back spacing of the carriage for repetition of any desired part of the record, the stylus is mounted in the carriage to have limited lateral swinging movement along the record, and provision is made for holding, and if desired centering, it during back spacing so that it rides along the record, lifting and lowering with the consequential offensive noise in the sound-box being avoided. The sound-box 17, Fig. 5, is mounted in the head 16 of a carriage 15 sliding on guide rods 12, 14 and traversed by a part nut 37 engaging a feed screw 38. The diaphragm 18 is connected by a wire 19 to the stylus lever 20, which is pivoted to a lever 26 mounted by pivots 27 to a bracket 29 capable of rocking by an inclined pivot connection 30 with the head 16. A spring 40 connecting the lever 26 and bracket 29 presses the stylus on the record 22, and the stylus can be lifted at any time and the feed disconnected by raising a rock lever 35, mounted on the rod 12 in a bifurcation of the carriage, so that a projection 34 on the lever engages an extension 33 of the stylus-supporting lever 26 and also an arm 36 of the pivoted partnut member so as to disengage this from the feed-screw 38. Back-spacing to a limited extent can be effected by depressing a lever 42 sleeved on a tubular extension 43 of the carriage. In the first part of this movement, a pawl 45 pivoted on the lever is brought into engagement with ratchet teeth on the edge of the part 46 of the machine and a notch in the lever sleeve rocks an arm 53 fixed in the pivot 39 of the part-nut member so as to disengage this from the feedscrew and simultaneously cause the arm 36 thereof to press a spring 49, adjustably secured to the carriage 15, so that its end 47 is pressed against the pivoted bracket 29 from which the stylus is carried, and thus prevents movement about its inclined pivot 30. During the further depression of the lever 42, the pawl 45 reacts from the frame to slide the carriage back for a small space, the stylus sliding on the record surface. A coil spring housed in an annular space between the lever boss and a fixed collar and bearing against lugs on these, returns the lever 42 after depression. The end 47 of the spring 49 may have a V recess to engage a V formation on the bracket for the purpose, when moved into action, of centering the stylus parts. The lateral movement of the stylus parts is controlled by a fixed loop 67 embracing with clearance a projection 68 from the lever 26. In a modification. Figs. 7 and 8. the bracket 29 is engaged by the spring at a point more distant from its pivot 30, for which purpose the bracket is formed with an extended curved arm 71, and the spring is extended to engage the end of the arm when the spring is actuated as previously described by depression of the lever 42. The spacing in this case is pivoted to a bracket 78 secured to the carriage, and its end 73 holds the arm 71 in the position it finds it, or the engaging parts may have a groove and projection for centering the stylus.