GB393397A - Improvements in means for indicating and recording angular positions of a rotatable member - Google Patents

Abstract

393,397. Recording-apparatus. BENDIX AVIATION COR. PORATION, 105, West Adams Street, Chicago, U.S.A. April 13, 1932, No. 10621. Convention date, April 13, 1931. [Class 106 (iv).] An apparatus for recording the angular positions of a rotatable member, as for example a wind vane, comprises a rack and pinion device for converting the angular motion into rectilinear motion and independent means whereby the rack is caused to move in a reverse direction, when it has reached the end of its travel in either direction, without affecting the rotatable member, the recording pen moving to a corresponding marked position on the chart. As shown applied to a wind direction recorder, the wind vane is connected to a shaft 4, Fig. 1, either directly or by means of a transmitter coupled to the shaft of a Selsyn motor. The shaft 4 is provided with a spider 3 to which is pivoted a spring-controlled arm 5 carrying a roller 6 bearing on a heart cam 8 bv means of which the movement of the vane is imparted to a spindle 12. The spindle 12 carries a pinion 13 engaging a rack 14 to which the recording pen arm 15 is attached. The pen 16 co-operates with a clock-driven record strip 18. The length of the rack 14 is such that one and one half revolutions of the shaft 4 will cause the pen to travel the width of the strip. The strip is graduated as shown in Fig. 2, and when the pen reaches an edge position, say N, it is moved to the corresponding marked inside position by means of a shift mechanism. This mechanism comprises a control shaft 22 carrying a gear wheel 21 and reversing disc 59. The wheel 21 is driven by a pinion 20 on the shaft 12 and on the rack reaching the limit of movement in either direction a pin 23 or 24 on the wheel 21 depending on the direction of rotation rocks a trigger 25 to operate a latch lever 35. The movement of the latch frees a roller 39 on an arm 28 of a toggle system 27 which operates, through a roller 40 on an arm 29, to close the contacts 44, 45 of the circuit of a solenoid 49 thereby causing the armature 50 to rock a lever 51 and shaft 53. The movement of the shaft 53 is adapted to cause reverse rotation of the shaft 22 by reason of the engagement of an arm 56 on the shaft 53 with one or other of the pins 57, 58 on the disc 59 whereby the pen is returned to the corresponding mark on the record strip or chart. After the contacts have been closed an arm 60 of the lever 51 engages an extension 62 on the toggle arm 28 whereby the contacts are opened and the toggle arms reset by the connecting spring 32 to normal position, the roller 39 on the arm 28 being held by a block 37 on the latch lever 35. The heart cam 8 and roller 6 prevent the reverse movement of the shaft 12 being transmitted back to the shaft 4.