Patent GB-1496196-A (GB)
Title: Molecular models
IPC: G09B23/26
Filed: 1975-03-04
Abstract: 1496196 Molecular models A DREIDING 4 March 1975 [7 March 1974] 8846/75 Heading G5G [Also in Divisions E2 and F2] Relates to a set of structural elements for making sterochemical models of molecules in which each atom is represented by a central body 30 having two or more arms 31a, 31b, 31c &c. radiating from it to represent valency bonds, the arms being each provided with a coupling device to enable it to be coupled to any other arm of the same or another element. In order to allow only certain permitted movements of the arms representing the bonds, each structural element has hinge structures between parts of the element associated with the various arms each including a device which resists pivotal or rotational movements of the associated arms from preselected relative angular positions, except when overriden manually. As shown in Fig. 1, a carbon atom is represented by two pairs of arms 31a, 31b and 31c (31d), the arms of each pair being arranged in planes disposed at right angles to each other. To enable these planes to be relatively rotated through 180 degrees, the central body 30 is composed of two parts 32, 33 which respectively carry the pairs of arms 31a, 31b and 31c (31d) and these parts are interconnected by a hinge structure, Fig. 5, consisting of a pin 34 passed through bores in the parts, heads 35 on the pin allowing slight movement of the parts away from each other, and springs 37 arranged around the pin in recesses 36 in the parts to urge the latter together. A longitudinal rib 39 on the part 33 can enter a groove 38 on the part 32 in either of two rotational positions of the part 33 relative to the part 32, such that either arm 31c projects forwardly, as shown, or the associated arm (31d, Fig. 3, not shown) projects forwardly, rotation being possible once the resistance of the springs 37 has been overcome, the springs thus stabilizing the element in one of two states corresponding to the different rotational positions. In addition the arms may be rotatable about their axes by a rotatable spigot 42 held within a socket in the body part against withdrawal by a pin 44 engaging a goove 43 in the spigot. This rotation may be biased to determine a number of preferred rotational positions by using a resilient pin (129, Fig. 22, not shown) and providing a corresponding number of flats in the base of the groove 43. Each of the arms consists of a closely coiled spring and the coupling device at the free end of each arm is of identical form so that each arm can be coupled to any other arm of the same or another element. Fig. 7 shows such a coupling device 50 as comprising a spigot 52 and a socket 53 each of semicircular cross-section formed on a plug 51 of resilient plastics material. A rib 54 on the spigot and a groove 55 in the socket, together with a slit 56 to enhance the resilience of the device allows snap-in fitting of the device to a similar device on another arm. Instead of a rib 54 and groove 55, a pair of hooks may be provided on a rotatable sleeve surrounding the spigot to obtain a bayonet connection in addition to a spigot and socket connection (Figs. 9-11, not shpwn). In another form of coupling device (Figs. 12-13, not shown) a permanent magnet having N and S poles at a coupling face of the device is used to couple to a similar device. Fig. 14 shows an alternative hinge between body parts 82, 83 of a structural element, a single spring 87 acting on a rod 89 to engage it in a groove (not shown) in part 82 in either of two rotational positions of the latter. In a modification, Fig. 16, serrated contours at mating surfaces of the body parts 102, 103 interfit in each of a number of rotational positions. In Fig. 29, notches 168 in a flat joint part 162 at the inner end of an arm 31a are engaged by a spring-loaded ball 169 carried by joint part 163 on the inner end of another arm 31b.