Patent GB-742805-A (GB)
Title: Improvements in and relating to apparatus for stereo photogrammetry
Inventor: ODLE JOHN ELSDON
IPC: G01C11/00
Filed: 1953-03-06
Abstract: 742,805. Stereogram metric apparatus. WIL. LIAMSON MANUFACTURING CO., Ltd. March 8, 1954 [March 6, 1953; Feb. 15, 1954], Nos. 6331/53 and 4423/54. Class 97 (1). In stereo photogrammetric plotting apparatus employing projectors and a movable plotting table, the table is carried on a small support guided to move parallel to a datum plane in such a way that the operator has ready access to the table, the latter being linked to the actual plotting means by a pantograph or other device. As shown in Fig. 1, the table 36 is supported on a carriage 16 movable transversely of the apparatus along tubes 14 and 15, this movement being effected by suitable gearing, not shown, operated by a hand wheel 53 on the carriage and engaging a rack on the tube 15, the gearing being disengaged electromagnetically from the rack by operation of a switch 54. The tubes 14 and 15 are supported at their ends on carriages 13 movable longitudinally on bars 12, each carriage containing gearing engaging a rack on its bar 12, the gearing being driven by a hand wheel 46 on the carriage 16 via gearing thereon, and a shaft 47a, the drive being disengaged electromagnetically when desired by operation of a switch 48b. A seat 22 for the operator is carried by a bracket 28 movable transversely on cross tubes 26, 27 which are supported on brackets 24 movable longitudinally along tubes 23. The brackets 24 may be connected by a hand lever 31 to the carriages 13 to allow simultaneous longitudinal movement of the seat 22 and the table 36. The bracket 28 also carries a wheel 37 rotatable by the foot of the operator to rotate a shaft 39 connected by universal joints to gearing within the carriage 16 which engages a rack 41, Fig. 5, on the vertically movable support of the table 36, whereby the latter may be readily raised or lowered by the operator which has hands remaining free. An image of a scale 42, vertically movable with the table 36 is projected on a screen 43 by a lamp 42a, condenser 42b, objective 43a, and reflectors 43b, 43c to indicate the vertical position of the table. The projectors 50, 55, Fig. 1, are supported above the table on a bar 56 along which they may be moved simultaneously in opposite directions by a screw 62 operated, through gearing, by a wheel 63. The projector 55 is adjustable perpendicular to the bar 56 by a rack and pinion operated by a knob 59, and both projectors may be tilted as desired by the rotation of rods 64 universally connected at one end to the projectors and at the other to the carriage 16 so as to move therewith, the rods having hand knobs 67 conveniently placed for actuation by the operator. To allow only a small portion of each photograph to be projected on the table 36 each photograph is illuminated by a narrow beam from a projector 68 mounted on an arm 71 rotatable about an axis passing through the front nodal point of the projection lens and adjusted in position by an arm 72 attached at the other end to the carriage 16. The movements of the carriage 16 in plotting are transmitted by an arm 79 to a pantograph 74 bearing a pencil 81 to permit copying at the same scale as the projected image or at a reduced scale. The pencil holder may have a lamp and an electromagnet which, when excited by operation of a foot switch 83 on the bracket 28, lifts the pencil from the paper on the table 75. Specification 742,467 is referred to.