Patent GB-826715-A (GB)
Title: Improvements relating to character font plates for photographic type-composing machines
IPC: B41B17/30
Filed: 1957-11-01
Abstract: 826,715. Photographic type-composing. MERGENTHALER LINOTYPE CO. Nov. 1, 1957 [Nov. 23, 1956], No. 34227/57. Class 98(1) A font plate assembly includes a rigid font plate fixed in a mounting frame for removable insertion in a photographic type-composing machine, the frame having registering means which, when urged into contact with positioning members in the machine, locate the frame with reference to the optical parts. As shown in exploded view in Fig. 2, the glass plate 21, on which the font of characters is produced photographically, is mounted in a frame 23 which consists of an apertured steel plate with side walls 24, a lower flange 26, and a tab 27 to which a hardened steel lug 31 is attached. Lug 31 and a member 34 fixed to the top of frame 23 serve to locate the frame in the camera wherein the font is produced and in the machine in which the font is used. During assembly, four needle bearings 36 are placed in slots 35 of the frame 23, and adhesive is placed in the corners of the frame. The plate 21, which at this stage is coated with unexposed photographic emulsion, is placed in the frame and pressed into contact with the needle bearings 36, more adhesive being placed round the edges. When the adhesive has set, the frame is placed in a camera for exposure, as shown in Fig. 8. The top locating member 33 is pressed into contact with discs 41 mounted on a backing plate 42 by a roller 43 mounted on a spring-loaded lever 82 to locate the plate vertically. The lug 31 is held against an anvil 45 (also mounted on plate 42) by a roller 44 carried on a spring- loaded rod 97; this locates the plate laterally. The face of the frame is engaged by spring-loaded arms 50. These force the needle bearings 36 into contact with plate 42. Since bearings 36 are in contact with plate 21, parallelism between plate 21 and plate 42 is ensured. The plate 2J. is exposed to the image of a master character font, and the frame is then removed by swinging a lever 52 which effects a sequence of unlocking operations during its movement. As shown in Fig 10, the lever 52 has a spring-urged locking pin 62 engaging before and behind a sector plate 64. It is unlocked by pulling knob 53, and the first part of its movement thereafter turns a disc 71, which is coupled to camshafts 75 carrying four cams 74. Each came co-operates with a rod 51 on which is mounted one of the arms 50 engaging the frame 25, being restrained from rotation by engagement between a slot 80 and a pin 77. The arms 50 clamp the frame by action of springs 76, but are advanced against the spring 1 by action of the cams 74 to release the frame. Further advance causes lever 52 to rock lever 82 by engagement with a roller 81 (Fig. 8) against action of a leaf spring 85, thereby withdrawing roller 43 so that the frame is no longer held against discs 41. In the last part of its movement, lever 52 engages a roller 86 on a rod 87 which is slidable in guides in member 90 fixed to frame 42 and having further guides in which rod 97 slides parallel to rod 87. The rods are connected for opposite movement by pins and slots in a lever pivoted centrally at 94 to the member 90, so that rod 97 moves roller 44 to release the lug 31. The frame with the exposed plate is removed and replaced by a unexposed one, which is clamped as before by return of lever 52 to its original position. The exposed plate is processed to produce visible characters thereon, and apertured masks 110, 111 (Fig. 2) are stuck on back and front. Specification 801,481 is referred to.