Patent GB-471531-A (GB)
Title: Improvements in or relating to platen rolls for typewriters or other recording machines employing a platen roll
IPC: B41J15/18
Filed: 1936-03-04
Abstract: 471,531. Rollers. SMITH & SON, Ltd., W. H. (Standard Register Co.) March 4, 1936, No. 6586. [Class 42 (ii)] [Also in Group XVI] A platen-roller for typewriters and like machines is divided longitudinally into two or more sections which are mounted on heads on a shaft and are readily releasable to permit of substitution of another platen-roller having a different length, surface, or other characteristic. The platen 12, Fig. 4, consists of a longitudinally - divided metal tube 13 provided with a cover 14 of rubber or the like, the longitudinal sections having engagnig tongues and grooves, and being riveted or welded to divided hubs 11. Conical bosses 10 on the hubs engage seats in heads 2, and each section of the tube 13 has a pin engaging a hole in one of the heads. The left-hand head is secured by a screw 6 to a shaft 1, and the right - hand head is freely mounted on a stationary tube 8, and is held in engagement with the associated hub 11 by means of a collar on the tube. The heads are provided with radially movable feed-pins 5 for engaging perforations in the stationery, the pins being projected and retracted by means of cams 23 which are secured to and splined on the tube 8 respectively. A platen of different length or surface can be readily substituted for that in use. In another construction, the platen sections are provided at the ends with notched collars which rest on cylindrical flanges on the heads and engage lugs thereon. The notches and lugs are preferably irregularly spaced or dimensioned to ensure that the platen is so mounted that the longitudinal joints do not coincide with the feed-pins, and are consequently prevented from being brought to the printing line as a result of line-spacing. The platen 115 shown in Figs. 10 and 14 comprises a longitudinally divided tube 116 clamped between heads 102, 103, each having a hub 104 provided with a key 105 engaging a longitudinal, groove in a shaft 100, one of the keys engaging also a slot 120 between the tube-sections. Each head is formed with a V-rib 111 engaging grooves in the end of the tube-sections. The head 103 is secured by a nut 112, and the head 102 is secured by a spring-catch 108 which can engage any one of a series of slots 109 in the shaft, the arrangement enabling a platen of different length or surface to be substituted. The tube is preferably so divided that the tubesections are slightly unequal, coincidence of the joints with the feed-pins on the heads, and consequently with the printing line being thereby avoided. Each tube-section is provided with a rubber cover 117 which is secured by vulcanizing, the tube-section being etched or roughened to ensure adhesion. To prevent stripping, the ends 121 of the cover are lapped over the, preferably bevelled, edges 118 of the tube-section and are then ground to provide smooth surfaces lying in radial planes or a common plane. The tube-sections are then placed together and the cover is ground to provide a smooth cylindrical surface. If a hard platen is required, a cover of celluloid, pyroxylin, or metal is employed. The spring-catch 108 may be formed at one side with a bevel adapted to bite into the sides of the slots 109. The nut 112 may be mounted on a collar which is splined to the shaft 100 and has a spring-catch for engaging the slots 109. The nut may be provided with internal lock-teeth co-operating with a tooth on the spring-catch. Specification 234,763, [Class 100 (iv)], is referred to.