Patent GB-365746-A (GB)
Title: Improvements in or relating to measuring instruments
IPC: G01K1/02
Filed: 1930-12-22
Abstract: 365,746. Measuring - instruments. BROWN INSTRUMENT CO., Wayne Avenue, Philadelphia, U.S.A.-(Assignees of Gray, A. W.; 1039, Oak Lane, Philadelphia, U.S.A.) Dec. 22, 1930, No. 38587. Convention date, Oct. 26. Addition to 365,284. [Class 106 (iv).] In an instrument of the type described in the parent Specification provided with means for compensating the instrument for dimensional changes in the exhibiting surface, such as the scale or record-sheet, due to variations in atmospheric conditions, the member utilized to effect the compensation is independent of the exhibiting surface. The invention is shown applied to a recording pyrometer provided with means for producing a record proportional to the quantity measured, and with means for adjusting the zero position, if necessary, on changing the record-sheet. The record-sheet 1, Fig. 1, is fed from a supply roll 2 over a driving roller 3 with pins 4 engaging perforations 5 in the record-sheet and the marking element is movable transversely of the record-strip by means of a screwed shaft 6 rotated in accordance with variations in the quantity measured. The marking element 13 is supported on the shaft 6 by means of a carriage 8. The carriage is provided with a member 9 engaging the spiral groove in the shaft 6 and with lugs 11 resting on a stationary bar 12. The marking element 13 is formed on the end of a tongue 14 passing through a slot in the carriage 8 and is bent up to form a top plate 16 with lugs 17 forming bearings for a spindle 18 secured to lugs 19, 22 on the carriage. Pivoted to the tongue 14 and plate 16 is a yoke member 23, Fig. 3, the lower arm of which has an extension 26 with a roller 27 adapted to ride on the surface of a bar 29. A spring 20 normally tends to force the tongue 14 to the left as shown in Fig. 1, thereby forcing the bridge member 30 of the yoke against a projection 31 on the carriage and the roller 27 against the surface 28 of the bar. The bar 29 is supported at one end on a bell crank 32 and at its other end on an arm 34 pivoted to a bell crank 36. The lower arm 38 of the bell crank 36 bears against a plate 39 on an arm of a bell crank 40 the other arm of which has a pin 43 engaging perforations in a pair of plates 45 between which is clamped a strip of material 48 similar to that of the recordsheet or subject to dimensional changes proportional to those of the record-sheet. The other end of the strip 48 is secured in a similar manner to plates 49 co-operating with a bell crank 54. Changes in surrounding conditions such as humidity or temperature cause an expansion or contraction of the strip 48 and record-sheet 1 and the movement of. the strip is transmitted to the bar 29 which acts on the roller 27 to shift the tongue carrying the marker to compensate the record. The surface 28 of the bar 29 is shaped to an appropriate contour so that the marker is moved through a uniform distance for equal increments in the quantity measured. If it is desired to adjust the zero indication the bell crank 54 is angularly adjusted on its pivot by means of an eccentric pin 59 engaging a slot in one of the arms of the bell crank. A manual adjustment of the zero may be effected by altering the position of the bell crank 32 supporting the bar 29. The marking element 13 co-operates with a carbon ribbon 14<1> to produce an intermittent record, the bar 29 being depressed periodically by rocking the bell crank 32 through an extension 60 operatively connected to an operating part of the instrument. In a modification wherein a continuous record is produced the marking element is constituted by a capillary tube 75, Fig. 5, and ink-well 74 carried by sheet metal clips 76 and tongues 77 supported on arms 79 of the marker support 80 that is adjustably mounted on the carriage 70. A thrust spring 84 between lugs 85, 81 on the carriage and support respectively tend to force the support to the left to cause the roller 27 to bear on the surface of the bar 29.