Patent GB-760401-A (GB)
Title: Improvements in or relating to temperature recording apparatus
IPC: G01K1/02
Filed: 1953-08-31
Abstract: 760,401. Recording-apparatus. BIRO, L. J. Aug. 31, 1953, No. 23979/53. Class 106 (4). [Also in Group XX] A clinical temperature-recording apparatus comprises a heat-conducting plate for engagement with a part of the person, a temperaturesensitive element so arranged in association with the plate as to be responsive to changes in temperature thereof, a mounting in which a chart may be carried, a temperature-indicating member coupled to the element and movable thereby in accordance with temperature changes across a chart carried in said mounting, and driving means by which the chart may be moved past the indicating member and brought intermittently into marking engagement with the chart. As shown in Fig. 4, the temperaturesensitive element b consists of a bi-metallic spiral contained in an oil-filled metal housing 5. The housing is thermally insulated, but is in thermal contact with a metal plate 1 at the base of the instrument, which plate is placed in contact with a part of the person. The free end of the bi-metallic strip is connected to a shaft 6 extending through a bearing 7 in the wall of the housing 5. The shaft 6 carries a crank arm 8 with a pin 9 engaging a projection 51 which depends from lever 10 (see also Fig. 5). Lever 10 is connected to parallel links 11, which are connected through gearing to a needle 2 movable over a chart d. The needle 2 and its associated mechanism are mounted in a part c, which is pivotally supported on the instrument casing by a pair of screws 16. An arm 17 attached to the part c is spring urged against a cam surface 19 operated by a clockwork mechanism a. Cam 19 has a saw-tooth periphery, which causes the part c to be rocked at intervals from its normal position, in which needle 2 is held above the chart d, into a position in which a point 22 on the end of the needle 2 perforates the chart, the needle point entering an arcuate groove in a platform 25 over which the chart is drawn. The chart d is wound up on a roller 26, which is detachably secured in the casing of the instrument, and is driven by the clockwork mechanism a through gears 34, 33, an axle 32, and a further pair of gears 31, 30. The whole of the instrument is mounted on a thermally insulating base plate e with a thermally insulating cover 40. The clockwork mechanism a is wound by means of a key fitting a squared shaft 21 extending through an aperture 41 in the cover 40, in which also a window 60 for viewing chart d is formed. In use, the instrument is strapped e.g. to the patient's wrist. The clockwork mechanism a drives the chart past the needle, and at regular intervals causes a perforation to be made in the chart indicating the patient's temperature. Clips may be provided for holding the part c in inoperative position when the instrument is not in use. Cam 19 may be modified to provide a small step before each peak, to shake the bi-metallic element slightly to make the temperature record more accurate. The bimetallic element may be contained in a doublewalled vessel with a vacuum between the walls, or the space between the walls may be filled with thermally insulating material. In a further modification, Fig. 9 (not shown), the bi-metallic strip is wound in a flat spiral enclosed in a double-walled vessel with a vacuum between the walls.