Patent GB-713731-A (GB)
Title: Improvements in or relating to teaching apparatus
IPC: G09B23/04
Filed: 1949-12-06
Abstract: 713,731. Educational appliances. BASS, W. A. G. Dec. 6, 1950 [Dec. 6, 1949], No. 31334/49. Class 146(2) Apparatus for teaching mathematics comprises a rigid carrier having a rectilinear scale thereon calibrated from zero, a number of separate rectilinear scale elements each calibrated from zero and each adapted for alternative attachment to the carrier so that the zero calibration thereof is always located at the same position on the carrier, and index means, which comprises a rigid element having a free edge to be placed in exact register with a calibration mark on a scale and can include blocks or counters on a movable straight edge, adapted to be selectively located on the carrier in registration with a calibration mark of at least one of the said scales. In the set of articles of which Figs. 2 and 11 show part, an L-shaped carrier 1 with a short arm 1b and longer arm 1a having a ledge 2 calibrated on its top surface with a scale 3 and at the zero calibration, a pin 4 is secured by a plate 5, the pin 4 serving to locate a detachable scale 10 by passing through a hole on the zero calibration of that scale. The zero calibrations of the scales 3, 10 are aligned with the inner edge 6 of the arm 1b and blocks or counters 7, dimensioned to register with a scale 3 or 10 are placed against the scale and can be used to demonstrate addition, multiplication and so on. Groups of blocks may be in different colours. An opaque mask may be arranged to slide over the scale 3 so that the numbers can be shown in turn and a short mask, marked as with an "X," can be slid over any one calibration number. The arm 1b has fixing devices 17 for co-operation with devices 18 on a protractor 16 so that the origin coincides with the zero pin 4 and the scale 10 can be pivoted on the pin for counting angles marked on the scale 19. In the apparatus shown in Fig. 12, a board 21 has a pair of scales 22, 23 down one side, at least one of which is detachably mounted, and a scale 24 along the bottom. A pair of straight edges 26, 27 are mounted for movement parallel to the edges of the board by means of cords 32, 34 and 36, 37 respectively clamped at 33, 33a and 35, 35a to the straight edges and passing round pulleys 28 and 29 respectively, mounted on pins 30 supported in forked brackets 31 secured at the corners of the board 21. A grooved gap 38 is arranged between the scales 22, 23 in which blocks 39 can be slid, the length of each block corresponding to one of the two scales 22 or 23. As shown in Fig. 12, the scales 22, 23 are provided with dowel pins 40 fitting into sockets in the end wall of a shallow recess 41 formed in the surface 21a of the board so as to be easily removable and the top edge of each scale is held by a clip 42. As shown in Fig. 14, the scale 22a is secured to a detachable carrier 44 having a dovetail 45 sliding in a groove 43 in the edge of the board 21. The scale 23a is also detachable. In a further modification, the scale 22a is secured to a block which is joined to the board 21 by an underlying metal plate screwed both to the board and the block, leaving a groove similar to groove 38a. A channel section opaque mask, marked as with an "X," can be slid over scale 22a. The board 21 is marked with a circular scale 25 and has a bearing socket at the datum point 0 into which a spigot on a radius arm or a clock face may be placed. A further scale, in another embodiment, is detachably mounted below scale 24 to leave a groove in which a slide may be inserted. Various other equipment for a classroom is also referred to.