Patent GB-756856-A (GB)
Title: Remotely controlled indicator
IPC: G08B5/32
Filed: 1953-05-05
Abstract: 756,856. Electric selective signalling system. WESTINGHOUSE AIR BRAKE CO. May 5, 1953 [July 1, 1952], No. 12521/53. Class 40(1) [Also in Group XL(a)] A display indicator comprises a plurality of wheels, an indiciabearing Moebius belt with an inner and one or more outer loops passing over the wheels with individual indicia located in uniformly disposed areas along the belt, a device for displaying one area at a time, and a selectively operable drive to bring any area before the device. In the embodiment of Figs. 2 and 3 an indicia-bearing twisted Moebius belt 28, the outer loop of which passes over an electroluminescent display panel 126, is located with respect to wheels 13, 21 by notches 28a engaging with projections 13d, 21d on the two wheels or by holes engaging pins on the wheels, the numbers of projections or pins on the two wheels differing so that each belt position corresponds to a different combination of wheel positions. The rear wheel 21 is driven by clutching its rim 21e to a constantly driven shaft 30 common to a number of similar assemblies through a jockey wheel 37 operated by electromagnet 32. Each of the contacts of code relays AR-FR (Fig. 22) is associated through a line 43A-43F with one of contacts 97-102 which are connected to contacts 75-77 and 86-88 by the remotely operated electromagnetic switch 93. The latter contacts engage points on the an nular region of one of the discs 47, 50 carried by the wheels. The regions are divided into zones alternatively connected to outer and inner continuous conductive annuli O, I, which are engaged by contacts 78, 89 and 74, 85 connected respectively to the positive end BX of a power source and through contacts 44a and b and the electromagnet winding 32 to the negative end CX. Consequently when a particular combination of relays AR-FR is energized circuits are completed to selected spring contacts of the group 75-77, 86-88 and thus so long as one of these selected contacts engages a zone connected to one of the outer annuli and thus with one of the contacts 74, 85 the electromagnet 32 remains energized to engage the drive. Only in one combination of positions of the two wheels will none of the selected contacts be thus connected and when this position is attained the drive is disengaged. When this happens, the belt is accurately positioned with one of the indicia centrally disposed on panel 126 by a magnetic detent mechanism. Switch 93 comprises an insulating body carrying an armature which draws it towards the indicator housing against springs 92. The connection between the fixed contacts 57a-59a and 62a-64a of this switch (not shown as separate members in Fig. 22) carried on insulating members 54, 55 and the conductive annuli is through the spring contacts 75-77, 86-88 (hot shown in Fig. 3) which are mounted in intermediate insulating plates. Magnetic detent mechanism (Fig. 7) A permanent magnet 17, which is mounted adjustably in the housing wall at 20 to allow of limited rotation, is of generally circular form with two pole face extension 17a which interact with a number of salient poles 16a on a magnetic ring corresponding with the notches 13d carried by the front wheel 13 in which the ring is housed, to bring the wheel to rest in one of eight distinct positions and to hold it there while the drive is disengaged. Alternative switch construction: In the arrangement of Fig. 16 the inner and outer conductive regions on the faces of discs 50, 47 are replaced by continuous strips in steeped recesses in the peripheries of wheels 103, 106 of insulating material, which are engaged by contacts 114, 115, 120, 121 and have segmental extensions 104b and c, 105b and c, 107b and c and 108h and c on the faces of the wheels corresponding to the extensions of the I and O annuli in the previous arrangement. The segments are engaged by spaced spring contacts 111-113 and 117- 119 mounted on insulating blocks 110 and having extensions engaging directly with the moving contacts 97-102 of switch 93. Further arrangements: In an alternative arrangement the electroluminescent screen is replaced by an apertured guiding frame an image of the part of the belt over said aperture being projected on to a screen by a light source and lens system.