Patent GB-978697-A (GB)
Title: Checking device for correspondence courses
IPC: G09B3/06
Filed: 1963-05-09
Abstract: 978,697. Educational appliances. E. RITTER. May 9,1963 [May 9, 1962], No. 18359/63. Heading G5G. A checking device for correspondence courses comprises a casing 1, Fig. 1, containing a paper strip 13, with correct answers to problems set on a sheet separated from the strip, and which is arranged on spools 9 and 10, mounted on shaft 5 and 6, respectively, the shafts being rotatable in opposite directions under the action of ratchet wheels (not shown) by knobs 8. The casing in provided with a window 17 below which there is arranged a mask 18 pivotally mounted on the shaft 5 in a bearing bush 19, rocking of the mask in the direction of arrow C by a removable handle 20 to indicate the correct answer to a given question such as number 51 (Fig. 2 not shown) which number appears in a window 29 of the mask 18. To enable the tutor to assess the students progress properly, when the students make use of the answers to solve the problem set, the answer is marked by punches 24 cooperating with a die 22, the punches being operated by a link 26 connected to a lever 23 carrying the punches 24 on rocking of the arm 20. The punches 24 also lock the paper strip 13 in position to prevent fraudulent advancement by the knobs 8, whereby tearing of the paper is prevented by slip clutches comprising a friction disc 11 and a flange 12 fixed on the shafts (Fig. 2 not shown). The mask may be replaced by a ground plate arranged centrally at the top of the casing and the answer made visible by an actuated light source, whereby the punches would be operated by an electromagnet energized on actuation of the light source. In another embodiment in which the paper strip is provided with four solutions A, B, C, D of which at least one is a correct one, a centrally disposed ground plate 30, Fig. 4, is overlying the paper strip 13, which is illuminated from below by lamps 33, the answer such as 51 is aligned with the window 29 in the glass plate 30 and a key 36 corresponding to the presumtive solution is depressed whereupon an arm 37 of the key closes contacts 40, 41 Fig. 5, of the lamps 33 to illuminate the strip 13 and an arm 37 carrying punches 37a, which co-operate with dies 38a, perforates and locks the strip to prevent its advancement. The keys 36 are provided with a varying number of punches 37a for identification of the solutions A, B, C and D. In a further embodiment, in Fig. 6, the depression of a presumption solution key 36, the paper strip is perforated and locked, contacts 40, 41, (Fig 8, not shown) actuating an electromagnet 51, whose armature 49a disengages a pawl 49 co-operating with a ratchet wheel 19a fixed to the mask 18, which may now be rocked to check the correctness of the answers. Rocking of the mask 18 raises a lever 54, whose pin 55 slides in a slot 56, so that any rocking of a depressed or raised key 36 is prevented. In a still further embodiment (in Fig. 9, not shown) the mask 18 may be rocked automatically by electromagnet on depression of any one of the keys 36. Unauthorised removal of the interchangeable paper strips is prevented by a locking arrangement 15, 16, Fig. 1, attached to a side cover 2 and casing 1, respectively, the key to the lock being retained by the tutor.