Patent GB-897259-A (GB)
Title: Latched tape reader
IPC: G06K13/24
Filed: 1960-05-13
Abstract: 897,259. Sensing punched record tapes. SOROBAN ENGINEERING Inc. March 13, 1960 [Nov. 13, 1959], No. 16998/60. Class 106 (1). A punched record reader has distinct sensing and record feeding cycles, there being perforation sensing members and operating means for moving them to and from the sensing position, a driving shaft, controlled means for selectively coupling the operating means to it for part of the cycle for the sensing operation and means for coupling the record feed mechanism to the drive shaft for a feed operation in response to a foregoing sensing operation and at a predetermined time after it. The driving shaft 1, Fig. 1, has a cam 11 to effect the record feed and a cam 21 to effect the sensing operation. A bellcrank lever 14 has a follower 19 bearing on the cam 21 to rotate an arm 17. This co-operates with a lug on arm 13 connected to shaft 2 which is urged in a counterclockwise direction and controls the sensing operation as described below. The operation of the reader is controlled by an arm 23 which, upon energization of a solenoid tends to move downwardly. There is an interlock between the arm 23 and an arm 18 of bell-crank lever 14 so that the arm 23 can only move downwardly at a particular time in the cycle. While in its upper position shown, arm 23, by its abutment 27 prevents counterclockwise movement of arm 13. When the arm 23, by energization of its solenoid and displacement of arm 18, reaches the lower position, it is retained in that position by the hook 31 of arm 13 which moves counterclockwise to follow arm 17. When the arm 23 is in the upper position, the tongue 35 on a member 34 which moves with it prevents a feeding operation taking place by restraining lever 47 from moving counterclockwise. The lever 47 is pivoted at 48 and is fixed to a lever 51 which carries on a hollow boss 54, Fig. 6, a feed pawl 7. This is rocked at each revolution of shaft 1 by engagement between cam 11 and follower 12 the movement of arm 9 being transmitted to the pawl by a member 10 slotted to engage the pawl. The pawl when in its lower position (Fig. 6) engages between the teeth of a toothed wheel 6 on shaft 3. The hollow boss allows a small rotation of lever 51 to lift the pawl out of engagement with the wheel 6. When the control lever is in the downward position therefore, the member 34 drops to free lever 47 for counter clockwise movement under the action of spring 52 and the pawl 7 engages the feed wheel 6 so that at the next oscillation of lever 9 the record is fed by one step to bring the next row of holes under the sensing pins. A spring-loaded roller 61 acts as a detent to hold the wheel 6 between feeding steps but this may be withdrawn by a solenoid to allow the tape to be pulled through the senser. Sensing.-The form described is for sensing an 8-hole tape. Eight pins 64, Fig. 9, arranged in a line across the tape are urged downwardly by spring arms 88 and are held up by a yoke 90 on arms 67, 68. The yoke is lifted to raise the pins by arms 83 on shaft 2 which engage rollers 86. Shaft 2 is seen in Fig. 9 from the direction opposite to that of Fig. 1 so that the direction of rotation appears to be opposite also. Clockwise rotation of shaft 2 in Fig. 9 allows the pins 64 to fall and sense the tape. Each pin has two contacts associated with it a normally closed contact above and a normally open contact below the spring 88. If the pin registers with a hole in the tape during a sensing operation it can pass through it and allow the upper contact to open and the lower one to close. Other contacts 101, 102 sense the position of the control arms 67, 68 to indicate to external apparatus that a sensing operation has taken place and allow the data impressed on the sensing switches to be transmitted. The feed shaft 3 carries a pin-wheel 77 for cooperation with the track holes in the tape, whereby the tape is drawn between the upper surface of body 75 and the lower surface of plate 74. A gear-wheel 70 on the shaft meshes with the gear on a mechanical counter accommodated in the space 90 counting the rows as they pass under the sensing pins. Alternatively, there may be in space 90 a number of contacts 115 operated by cams 111 on the driveshaft for reading the sensed data out in serial form. The tape is held in contact with the pin wheel by a presser 123, Fig. 10, mounted on a pivoted arm 119. The arm is held in its operative position by an over-centre spring, which also holds it in a raised position necessary for inserting the tape. The tape is formed in a loop, which acts as a buffer, between rollers 140 and 131, Figs. 9 and 10 by a wheel 124 bearing on the tape at this point to detect when the tape either becomes too tight or breaks. Excessive tension raises the wheel and rotates shaft 129 which through links operates a switch. If the tape breaks the roller falls and another switch is operated. The presser 123 is connected by a link with the wheel 124 so that when the presser is raised, the wheel 124 is also raised. Proofing against explosion.-The housing 173, Fig. 10, of the apparatus is sealed and ventilated through a gauze screen so that if the apparatus is working in an explosive atmosphere its ignition within the housing by sparks at the sensing pin contacts does not cause an explosion by ignition of the surrounding gases.