GB1236482A - An improvement in printer mechanisms - Google Patents

Abstract

1,236,482. Selective printing; numbering- machines. SHERWOOD MEDICAL INDUSTRIES Inc. 31 Jan., 1969 [2 Feb., 19681, No. 5472/69. Headings B6C and B6F. A print hammer mechanism comprises a reed 36 anchored at 38 and adapted to be vibrated in response to energization of an electromagnet 40, the vibrations being of a complex form permitting the free end 36b of the reed 36 to strike a type character 50a in different places during a single vibration. The reed, while vibrating, strikes a polepiece of the electromagnet 40 to modify the harmonic vibration of the reed. Type-wheel machines: type-selection.-The hammer mechanism is applied to a machine having four sets of wheels 46 each bearing numerical indicia. The right-hand pair of sets of wheels, Fig. 3, comprises a set of indicating wheels at the extreme right and a corresponding set of print wheels adjacent thereto. Type selection is effected in response to electrical input signals by a motor 59 driving a shaft 48 the shaft being coupled to a potentiometer 65 which nullifies the electrical input when the right-hand sets of wheels 46 are in a selected position. Each set of wheels 46 is cascaded so that ten incremental steps of a units wheel causes one step of a tens wheel and so on. A lost-motion assembly 63 protects the potentiometer 65 from high impact torque from the motor 59, especially at an end position of the potentiometer. Alignment for impression.-The setting of the wheels 46 is rendered accurate by an electromagnet 68 having poles 70 adjacent which teeth of a soft iron wheel 74 position themselves preferentially. When accurately set, the print wheels of the right-hand pair of sets are held in position by an arm 100 urged by a solenoid 107 to press the wheels together in an axial direction. Line-spacing.-After impression has been effected paper fed between the reeds 36 and wheels 46 is stepped one line space by a motor (80), Figs. 2, 6 (not shown), driving a shaft 90 through a chain 86. The motor is automatically switched on and drives so long as a switch 94, controlled by an arm 96 co-operating with a toothed wheel 98 on the shaft 90, remains closed, i.e. until the arm 96 strikes a tooth on the wheel 98. The printing is preferably carried out on a web of pressure-sensitive paper. Numbering-machines.-The left-hand pair of sets of wheels 46 indicate and print consecutive numbers for successive impressions of the righthand sets of wheels 46. A pawl 53 oscillated by an electromagnet 56 engages a toothed wheel 52 to step the units wheels 46 after each operation.