GB1039390A - Improvements in sheet feeding means in a high speed printer - Google Patents

Abstract

1,039,390. Selective printers. SPERRY RAND CORPORATION. Nov. 21, 1963 [Dec. 3, 1962], No. 46033/63. Heading B6F. [Also in Division F2] Web feeding, guiding and tensioning arrangements; pin-feed arrangements.-A high-speed printer including a type cylinder 13, and a plurality of linearly aligned hammers 11 mounted in a hammer head assembly 12 is provided with a sheet feeding mechanism for advancing continuous sheet material 10 past a printing station in line spacing increments which comprises pin feed tractor 15, 16, Fig. 2, supported on upper and lower shafts 20, 21 and 30, 31, respectively, arranged before and after the printing station defined by the lines of hammers 11. The lower shaft 30 is coupled via a coupling to a shaft 35 driven through an electromagnetic clutch 45 (see Division F2) to rotate in unison with the upper shaft 20 coupled to a shaft 25 which is driven by a belt 56 passing around pulleys 55, 57 fast with the shafts 35, 25, respectively. A tensioning device is provided to vary the tension in the belt in such a manner as to vary the angular displacement of the two shafts 25. 35 relative to each other and thereby vary the longitudinal tension in the sheet material and comprises a roller 90 carried by a lever 91 mounted pivotally on a pivot stud 92, whereby the roller 90 bears against the inner reach of the belt 56. Adjustment of the longitudinal tension in the sheet material is effected by manipulation of a control knob 95 attached to a threaded rod 93 passing through a stud 94 on the lever 91. Each tractor is provided with a pivoted plate 36 swingable into overlying relation with the sheet material 10 to hold the sheet material in engagement with sprocket pins 16 passing through holes 14 of the sheet material. Each tractor also includes a latch lever 37 for clamping the tractor to its supporting shafts and releasable to permit the tractor to be slidably adjusted along the shafts for accommodating sheet material of different width and for registering it with the printing station. Line spacing arrangements; blanking feeds.- To effect blanking feeds and line spacing the shaft 25, Fig. 2, is provided with an electromagnetic brake 70 comprising a brake armature hub 71 fast with the shaft and having mounted thereon a brake housing 72 secured to an arm 80, the lower end of which is bifurcated to receive an adjusting screw 84 extending through a stud 82 in a limiting block 83. A spring 89, Fig. 1, urges the brake housing and arm 80 in an anticlockwise direction, a limited angular displacement of the arm 80 and brake housing being effected by manipulation of a control knob 87 (Fig. 3, not shown) which rotates the screw 84. The brake housing co-operates with a reluctance head 61 supported by a head 62 linked to the brake housing by a link 81 via the arm 80. The reluctance head 61 co-operates with an index drum 61 which rotates with the shaft 25 and serves to generate signals indicative of the line space position of the sheet material. The drum 60 is formed with a series of perforations at predetermined spaced intervals corresponding to line space positions. For manual operation of the line spacing or blanking feed whilst the sheet feeding mechanism is inactive the clutch 45 is disengaged, the brake 70 engaged and the rotation of the knob 87 will cause pivotal displacement of the brake housing 72 and the reluctance head support 62, together with the index drum 60 and shaft 25 along with the tractors 15 which will position the sheet material at a selected index point of a line space position, which may be indicated by a scale mounted on the printer. If the control knob 87 is operated while the sheet feeding mechanism is active, the brake 70 will be disengaged so that the effect of the pivotal adjustment of the brake housing 72 and head 62 will be the application of the brake 70 on generation of subsequent signals by the reluctance head 61 at the point of sheet material advance corresponding to the selected position. Automatic line spacing or blanking feeds may be effected by an external line spacing control unit 98 (Fig. 5, not shown) forming part of a computer and in which the signals generated by the indexing drum 60 may be used as a reference signal indicating when the sheet material has advanced an extent corresponding to one line space position, the control unit effecting control of the clutch 45 and brake 70. To perform a single line spacing operation this signal is relayed to de-energize the coil 50 of the clutch 45 and energize a coil. If the machine is programmed to space a predetermined number of line spaces the signal generated by the indexing drum is utilized to activate a counting mechanism in the control unit 98 for determining the number of line spaces over which the material may be fed continuously before a signal is relayed to disengage the clutch and activate the brake.