Patent GB-390965-A (GB)
Title: Improvements in or relating to photographic printing machines
IPC: G03F7/22
Filed: 1932-05-18
Abstract: 390,965. Photographic printing- apparatus. STEVENS, A. H., 5, Quality Court, Chancery Lane, London.-(Eureka Photo Mechanical Equipment, Inc.; 33, West 60th Street, New York, U.S.A.) May 18, 1932, No. 14116. [Class 98 (ii).] A photo-reproducing machine comprises a bed frame supporting two carriages 16, 17, Fig. 1, which are mounted for longitudinal and transverse movement respectively upon two pairs of tracks 5, 6 and 7, 8, the said carriages supporting a plate-carrying frame 51 which is adapted to move freely with respect to one carriage while being rigidly secured to the other. In the form shown, the apparatus is supported on legs 1 .. 4, to which the tracks are rigidly secured. Inwardly extending arms 9 .. 12 are also secured to the legs and serve to support a table base 13 carrying a sensitized surface table 14. As shown in sectional elevation in Fig. 6, the carriage 16 comprises a cross-bar 31 and two end members 18, 27, the member 18 of which carries four rollers 19 .. 22, and resiliently mounted wheels 26 engaging with the track 6. The other member 27 carries wheels 28, 29, 30 which resiliently engage with the flat upper and lower surfaces of the track 5. In order to ensure that both ends of the carriage move at the same speed, a shaft 33 is journalled in a bracket 32 carried by the members 18, 27 and is provided with gear wheels 34, 35, which mesh with racks 36, 37 on the supporting frame. The carriage 17 is supported in a similar manner on the tracks 7, 8. The frame carrier comprises two frames 52, 53, the outer frame 52 of which carries four rollers 54 .. 57, Fig. 4, which rest upon the upper surfaces of rack bars 40, 50, carried respectively by the crossbars 31, 43. The spindle of each roller is eccentrically formed on a stud 58 secured to the frame 52 so that the carrier can be levelled by an adjustment of the studs. The frame 52 also carries a housing 60 which partially surrounds the cross-bar 43 and houses a grooved block engaging with the underside of the cross-bar. A screwed rod journalled in the housing 60 and having an operating handle 63, engages with this block and, when rotated, serves to produce relative movement between the frame 52 and the cross-bar 43. This relative movement either locks or unlocks the frame with the cross-bar by bringing the internal V-shaped teeth of a collar 71 into or out of engagement with the teeth of the rack bar 50. The collar is normally free to be rotated and is locked in the required angular position by a cam 80 which moves it axially into locking engagement with a plate 76 secured to the housing 60. Similar locking mechanism is provided between the frame and the crossbar 31. In the form shown, the locking is effected by a handle 88 each end of which is screw-threaded internally to engage with a screw on the frame 52. In adjusting the carrier it is first locked to one cross-bar and then moved with respect to the other cross-bar until a pointer 127 or 129 approximately registers with a predetermined marking on a scale 128 or 130 provided on the cross-bars. A fine adjustment is then obtained by rotating the nut 71 and manipulating the cam 80. Locking is then effected by means of the handle 63 or 88 and the process is repeated with respect to the other cross-bar. The inner frame 53 of the frame carrier is vertically adjustable with respect to the frame 52 to which it is connected by a series of pins 64 and slots 68, Fig. 7. Each side of the frame 53 carries a vertical rack and with these racks engage the pinions 95, 96, 99 of two shafts 91, 92, journalled on the sides of the frame 52. These shafts are geared together at 93, 94, so that a true vertical movement is imparted to the frame 53 when the shaft 91 is rotated. The shaft 91 is hollow and at one end is connected by a tube 116 to the suction frame 100 carrying the photographic plate ; the frame 100 is supported by ball and socket assemblies on the frame 53. The other end of the shaft 91 passes through a fixed journal 109 and is rigidly secured to a valve head 100. A valve 111 is pivotally mounted on the valve head and carries a handle 120 for rotating the shafts 91, 92, and a tube 115 leading to a vacuum chamber. In the operative position of the valve, the suction frame is in direct communication with the vacuum chamber and in this position an arm of a bell-crank lever 122 pivoted to the valve head engages between two projections 124 on the journal 109. The frame 100 cannot therefore be raised while under vacuum. In the inoperative position of the valve, a pin 121 thereon engages with the bell-crank lever 122 which is thus freed from the projections 124.