GB604191A - Improvements in or relating to course-recording apparatus - Google Patents

Abstract

604,191. Course-recording apparatus. COE, H. J. F. May 19, 1944, No. 9757. Convention date, June 10, 1943. [Class 97 (ii)] Apparatus mounted in a vehicle for surveying by transit over a given path comprises a chart carrying platen 2 pressed by a stylus carrying member 6 against a rough surfaced driving wheel 4, rotated at a speed proportional to that of the vehicle, and is manually orientatedabout the point of contact between the platen and the wheel 4 in accordance with the indications of a compass visible from the operating position. As shown the chart platen 2 rests on pimples 9 on a base plate 10 and is pressed against the knurled edge of the driving wheel 4 by ball bearings 7 on a spring-loaded annular member 6 which is secured to the stylus 8 and slidably mounted in the support 19. The stylus 8 and driving wheel 4 are carried respectively by the arms 20 and 21 and form a pivot about which the platen 2 may be rotated by hand to maintain a constant orientation. To facilitate this operation the chart is marked with a series of parallel lines and is viewed by. reflection on the semi-transparent mirror 12, whilst a compass 11 with parallel line markings is reflected by the mirror 12 on to a second mirror 13 and is viewed through'the mirror 12 superposed on the chart image. The wheel 4 is driven through gearing 24, 25, shaft 26, gear-box 27, and flexible connection 28 by a speedometer, air speed indicator, or ship's log. The apparatus is suspended from the framework of the vehicle by damped gimbals 29. In the case of a vehicle moving over uneven ground, the speedometer drives a conical member 37, frictionally driving a member 36 carried on a shaft 35. The latter is moved axially by link 34 and crank-arm 31 which may be secured to the gimbal trunnion 32 when desired. Thus the speedometer drive is automatically modified so that the shaft 35 and flexible connection 28 rotate at a speed proportional to the horizontal component of the vehicle's speed. The driven member 36 may be adjusted axially on the shaft 35 by a micrometer nut 40 to compensate for tyre wear. The gear box 27 enables the scale of the chart to be varied. In a modification for use over very rough ground, the vehicle is dispensed with and the apparatus carried and driven by a light wheel of measured circumference. The Specification as open to inspection under Sect. 91 comprises also the subject-matter of Specification 604,263. This subject-matter does not appear in the Specification as accepted.