Patent GB-716557-A (GB)
Title: Improvements in or relating to display mechanism for articles and goods
IPC: G09F11/23
Filed: 1952-07-21
Abstract: 716,557. Moving display apparatus. LAMM, A. M. July 21, 1952 [July 26, 1951], No. 17777/51. Class 3(1) Display mechanism suitable for rotating an exhibit comprises a supporting member on which the exhibit or a cradle carrying the exhibit may rest, and means for imparting oscillations to the supporting member through a small angle around substantially the same axis as that around which the exhibit is to rotate, which oscillations are such that the angular 'speed and/or acceleration of movement is greater in one direction than in the other and the nature of the supporting surface of which supporting member is so chosen, having regard both to the inertia of the exhibit and the cradle when the latter is used and to the nature of the supported surface of the exhibit or of the cradle which carries it, that during the slower of the two movements of the supporting member, the exhibit is caused wholly or partly to follow the movements of the said member, but during the faster of the two movements, the inertia of the exhibit and of the cradle when the latter is used, prevents it or them from following the movement of the supporting member to the same angular extent as during the slower movement. As shown a platform 20 is supported by four spring steel posts 21 from a heavy base 22 and carries on its underside two armatures 26, each of which is associated with an electro-magnet a The electro-magnets a are supported by standards 220 from the base 22 and when energized cause the platform to rotate slightly. When the electro-magnets are de-energized, the spring posts 21 return the platform to its original position. The platform and electro-magnets are concealed by a sheet 30 of canvas or the like and a glass tumbler 28 is positioned on the cover over the rotational axis of the platform, the platform and tumbler forming the supporting surface. The platform is arranged to be moved faster by the spring posts 21 than by the electromagnets so that an object 29 supported by the tumbler is caused to rotate to a greater extent in one direction than the other. The electro-magnets are energized fifty or sixty times per second and the object consequently appears to rotate unidirectionally. The tumbler may be prevented from lateral displacement by raising the cover 30 slightly inside the tumbler by a disc joined to the platform underneath the cover. The spring posts 21 may be arranged at an angle to the vertical so that the platform is raised slightly when it is attracted by the electro-magnets and falls when the posts return it to its initial position. This tends to decrease friction during the return movement and aids the movement of the object 29. In an alternative construction, the armatures are attached to a plate which is supported in a casing by two spring wires arranged along the diagonals of the plate and attached to it at its centre and each attached to the casing at each end. The plate supports a channel shaped transparent bracket which carries a rota'table cradle on which the display object is supported. The cradle is centred on the bracket by a pin and between the bracket and cradle is a washer of textile pile, the fibres of which offer greater friction to movement caused by the electro-magnets than to movement caused by the spring wires. The electro-magnets are energized from an A.C. supply through a half-wave rectifier.