Patent GB-552464-A (GB)
Title: Improvements in or relating to educational devices
IPC: G06K17/00
Filed: 1941-11-05
Abstract: 552,464. Examination statistics compiling. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 5, 1941, No. 14291. Convention date, Nov. 2, 1940. [Class 106 (i)] [Also in Group XV] Relates to a machine for sensing examination sheets upon which an examinee has designated responses by means of pencil marks as in Specification 530,093, and comprises the provision of a graph printing device consisting of a row of printing wheels one for each of a selected number of positions for each sheet sensed, each wheel being stepped ahead for each mark sensed in the related position so that the total advance of each wheel represents total marks sensed in the related position of a group of examination sheets. The " sensing, " " resistor," and " selector " units 10, 17, 21 are as described in the aforesaid prior Specification, the sensing blades 12 extending into slidable cups 13 which contact resistor elements 18 and these in turn selector elements 22. In'the present invention a plug-board unit 26 is added to the machine. Plug-board unit.-This comprises a panel 26 of insulating material in which plug-sockets 27 are provided, one for each possible marking position, in alignment with the selector pins 22. At its lower end, the panel is provided with sockets 28 which may be connected with any of the sockets 27 by wires 29. After the panel is placed in the frame 30, the latter is moved to the left, Fig. 1, so that the sockets 27 abut against the pins 22. Response sheet handling mechanism.-As in the prior Specification, the response sheet R is inserted in a chute 16 and drops on to a shutter 33. An operating key 34 is now depressed. This, after the main switch is closed causes the circuit of the motor M to be made and the clutch disc 63 to drive through half a revolution when it becomes released.' The disc works a toggle 75, 78 to move the platen 83 and press the sheet R against the sensing blade. The pencil marks control circuits for printing. Following this, the key 34 is depressed a second time for the clutch to make another half revolution, the toggle is again broken and the shutter withdrawn to allow the sheet R to fall into a hopper. Certain control contacts are operated by the mechanism during these movements. Printing mechanism.-This is mounted in a frame 100, Figs. 1, 6. The printing wheels 101 are ratchet wheels with a number of teeth omitted opposite the platen 102. Under control of the sensing devices, the ratchet wheels are stepped ahead. Later, when printing is to be effected, the platen is moved against the wheels and these are rotated in the opposite direction back to their home position, the high points of the teeth making lines of marks on the second sheet. The wheels 101 are frictionally held on 'a shaft 103 grooved to provide rings 104 on which the wheels are supported. In the grooves are located semi-circular members 105. Each wheel has pins 106 between which spring wires 107 are flexed against the members 105 so that each wheel has an individual frictional connection to the shaft 103. During the setting of the wheels, the shaft is stationary. In the same plane with each wheel is a pawl 108, these being arranged in two rows. The pawls are actuated by a pair of magnets CR, CL one pair for each row. These are supported in a carriage 120 moved parallel to the line of pawls. With a magnet in line with any of the pawls 108, energization of the magnet will attract and rock the pawl. Due to the spacing of the pawls 108, the magnets CR, CL alternate in aligning with them, that is, the core 117 of magnet CR first aligns with a pawl 108 in the right hand row and then the core of the magnet CL with the next pawl in the left hand row and so on. The magnets are on a travelling carriage 120 to which is secured pairs of rollers 121. The rollers of each pair are located to either side of the core 117, so that, after the pawl has been elevated, one of the rollers 121, depending on which direction the carriage is travelling in, will strike against the raised pawl and depress it back to the original position advancing the ratchet wheel 101 one step. Rotatably mounted on the carriage is a member 123 threaded upon the driving shaft 124 driven through belt and pulley 126, 125 from a shaft driven through gearing and a slidable coupling from an auxiliary motor. Extending through the member 123 is a pin 134 which abuts against the end of a T-shaped arm 135 slotted at 136 and pivoted at 137 in the carriage 120. Springs 138 hold the arm 135 between the member 123 and the carriage 120. When the latter reaches the right hand side, Fig. 6, the pin 134 will project into the plane of an arm 139 on the shaft and the arm will strike and rotate the pin together with the member 123 forcing the springs 18'to yield and rocking arm 135 to slopein the opposite direction to the Fig. 6, position. Further movement of the carriage cannot take place as long as the shafts 124 rotates in the same direction. To return the carriage to the left the rotation of the shaft 124 is reversed. When the carriage arrives back, a second arm 140 secured to. the shaft will engage pin- 134 and the arm 135 is snapped' back to Fig. 3 position the member 123 revolving, with the shaft without traversing the carriage. At one extreme position, an arm 141 on the carriage closes pairs of contacts 142, 143 and at the other extreme position, the arm opens contacts 144 and closes contacts 145. Wiper blades 146 traverse conducting blades 147 for supplying current to magnets CR, CL. The carriage. also has two U-shaped contact wipers 148 which traverse common blade 149 and individual blades 150 corresponding. to. the number of ratchet wheels 101. The upper extremities of blades 150 make connection with the plug sockets 28. As the carriage traverses shaft 124 and the magnets CL or CR. are in line with selected wheels 101 either one is energized to free pawl 108 to engage the next tooth. As the carriagecontinues, the wheel 121 will forcibly return, the pawl to advance the ratchet wheel one step. The carrier travels in one direction while one sheet is sensed and returns while the next sheet is being sensed. One of the ratchet wheels which is advanced one step for: each operation of the machine carries a pin 151 which opens contacts 48 after the wheel has advanced a certain number of steps-in this case 100. To print, a record sheet R3, Fig. 11, with a carbon sheet between it and the wheels, is inserted, theleading edge abutting- against shoulders on spring-pressed fingers 153. The handle 161 is then rocked counterclockwise so that the pin 156 releases the arm 155 whereupon springs 158 swing the platen 102 against the wheels 101. This rocking of the arm 155 through, links 163, 165 causes the frame 109 to, rock about the pivot 110 to cause lifting of pawls 108 out of engagement with the ratchet wheels 101. One arm 155 is connected: by linkage to the clutch member for the auxiliary drive. When the linkwork is moved to disconnect the shaft 128 from the auxiliary motor, the clutch member is shifted so that motion is conveyed to the wheel supporting shaft 103. The wheels 101 are rotated back to normal position while the platen is pressed against them to print on the sheet. Certain, contacts are also opened and closed when the shaft is rocked by handle 161. Stops 187 are provided on a crossrod 186a carried by an eccentric portion of the shaft 160 to mark the home position of the wheels 101. When the handle 161 is rotated, the stops are withdrawn out of the path of pins 186 on the wheels. Circuit diagrams are described involving the use one of three thermionic valves and the other of two valves. " Commoning " sheet-This is a sheet to be used with the perforated, " key " sheet described in the prior Specification. It is the, same size as the " key " sheet and has a layer o conducting ink forming a band connecting the position of the five holes to. a question of the key sheet. A similar band is on the other, face of the commoning sheet and the bands are connected by minute conducting perforations. The prepared " key " sheet, which has already been perforated for use in examining the individual response sheet, is then placed backed by a " commoning sheet " clipped to it at 31 and the plug 27 may be placed in any plug hole for that question, and left there when the key sheet is exchanged for another. The. description also explains how the second circuit diagram may be used to enable an analysis to be made to determine whether related questions of certain. pairs have both been answered correctly and to indicate this on the graph.