Patent GB-1257817-A (GB)
IPC: G07C1/06
Filed: 1969-07-01
Abstract: 1,257,817. Time and date printing apparatus; roller impressions; ink-ribbon mechanisms. MITE CORP. 1 July, 1969 [20 Nov., 1968], No. 33244/69. Headings B6D and B6F. A time and date printing apparatus for impression of documents 76, Fig. 6, placed on a support 16, Fig. 3, comprises a coaxial set of time printing wheels 164, 168 and 172 associated with respective ratchet wheels 166, 170 and 174 which are driven by a pawl assembly 148 actuated by a timing motor 132 and an impression roller carriage 24 reciprocated by a 'crank drive to traverse an impression roller 30 along the axis of the time printing sheets. The apparatus is also provided with date printing and indicating wheels 178, 182, 186 and 200 which are settable manually. The time printing wheels are driven intermittently by the timing motor 132, Fig. 3, through the intermediary of a cam 136 which co-operates with a cam follower 138 attached to one arm 140 of a yoke 142 which supports pivotally the pawl assembly 148 having several parts which are allowed to co-operate with their respective ratchet wheels when the pawls associated with the minute time printing wheels engage respective deeper teeth such that on elapse of nine minutes the time printing wheel associated with the tens of minutes may be advanced one integer and when the latter has been displaced through five integers the hour printing wheel may in turn be advanced one integer. The time printing wheels 164, 168 and 172 are provided with respective time read-out discs 194, 192, 190, Fig. 6, such that the instant time may be displayed in a window 20 provided in the housing. The date printing wheels 178, 182 except for the day printing wheel 186 are provided with diametrally opposite positive month and year indications which jointly with a diametrally opposite positive indication of the day on a separate wheel 200 are displayed in a further window (22, Fig. 1). Impression arrangements.-To date the document 76, Fig. 6, the latter is placed on the support 16 and moved against a trigger 78, Fig. 3, which pivots about a pin 83 in a clockwise direction so that its arm 86 can release a spring-biased arm 83, Fig. 8, whose tab 82 allows a micro-switch pin 81 to close the drive circuit of a motor 48, Fig. 3, having a worm 50 which meshes with a worm gear 52. The worm gear 52 is driven through one revolution to operate the crank 54 for reciprocation of the impression carriage 24 through crank-pin 52 and yoke arm 60. The carriage which is spring- biased in the impression direction is mounted at its front end on rollers 26 which during impression movement ride up a guide ramp 32 provided at its rear end with a recess 44 such that the rollers 26 can drop into the base-plate 40 following impression of the document 76 against the type wheels by the impression roller 30. Return movement of the carriage 24 takes place along the base-plate 40 and the crank drive 52, 54 stresses the spring 74 which biases the impression carriage 24 so as to reduce any backlash in the drive gear. Towards the end of the restoration of the carriage 24 the latter lifts the guide ramp 32 so that the carriage may again be presented for impression. Repeat impression is prevented by an interposer (95, Fig. 7) against which the arm 83 comes to rest following restoration by a pin 87 on the crank 52 should the document be left in the apparatus and the trigger 78 be in its displaced position. Ink-ribbon mechanism.-An ink ribbon 92, Fig. 4, is supplied from a supply spool 94 and wound on a take-up spool 96 both of which are prevented from transverse displacement by mounting them in recesses 98. The take-up spool is ratchet driven once every predetermined number of impressions to present a fresh portion of the ribbon below the printing wheels. The drive is effected by means of a pair of axially spaced ratchet wheels 102, Fig. 5, and (126, Fig. 2) which co-operate with a respective one of a pair of pawls 106, 120 which are fast with a pawl carrier 108 mounted pivotally at 110 on a bell-crank lever 112 whose arm 114 is displaced by the trigger-restoring pin 87. The ratchet wheel 102 has a number of teeth corresponding to the number of predetermined impressions, one tooth 104 having a greater depth permitting the pawl 120 to engage its associated ratchet wheel (126) and rotate the take-up spool 96.