GB703776A - Improvements in or relating to instruments for making orthoptic exercises and tests - Google Patents

Abstract

703,776. Stereoscopes; sight testing. ASHER, H. M. F. May 21, 1952 [May 4, 1951], No. 10561/51. Class 97(1) In a stereoscopic apparatus having a pair of objects visible respectively through the eye apertures of a stereoscopic eyepiece device, the objects are respectively mounted upon a pair of guides extending forwards away from the observer so as to be movable towards and away from the eyepiece, the guides being relatively movable laterally to vary the separation of the objects. As shown the viewing means comprises a plate 10 carrying lens 17 and 18 and a bar 13 to which is fixed a rod 23 fixed by members 30, in slots in the bar 13 are the ends of rods 28, 29 the other ends of which are pivoted to links 40, 41 pivoted in turn to a flange 27 on a knob 26 rotatable on the bar 13, rotation of the knob thereby varying the angular separation of the rods 28, 29. Slidable respectively on these rods are blocks 44, 45 supporting. the objects to he viewed, for example two cards 46, 47. The blocks 44, 45 are apertured to receive freely a transverse rod 56 fixed to a slider 57 movable along the the bar 23 by a universally mounted handle 59. Movement of the slider 57 along the bar 23 varies the distance between the objects 46, 47 and the viewer, while the bar 56 ensures correct orientation bf the objects as their distance apart varies according to the inclination of the rods 28, 29. The slots the bar 13 allow adjustment of the separation between the fixed ends of the bars 28, 29. In a modification a septum is fixed to the bar 23 and panel 10 to ensure stereoscopic vision, the ends of the bars 28, 29 extend beyond the pivots 38, 39 to terminate in horizontal jaws sliding on a horizontal bar fixed to the end of the rod 23. In addition the bar 13 is replaced by a triangular plate having a continuous slot to allow the ends of the bars 28, 29 to be juxtaposed.