Patent GB-115342-A (GB)
Title: Apparatus for Recording Mechanically Transmitted Orders from a distance to an Engine Room or elsewhere.
Inventor: AHERN JAMES
IPC: B63H21/22
Filed: 1917-07-23
Abstract: 115,342. Ahern, J. July 23, 1917. Fluid speed indicators; particular-speed alarms; revolutiondirection indicators; speed indicators with indicating and signalling apparatus; t i m e - distance and time-revolution recorders.-Apparatus for recording orders given by ship telegraphs &c. and the manner in which the orders are complied with comprises a travelling- strip chart on which a marker traces a line which, when the engine is running, is wavy or zigzag, but is straight when the engine is stopped. The chart is ruled with longitudinal columns corresponding to the orders, and with transverse time lines. The transverse position of the marker is determined by the order given. The pitch of the zigzag markings is determined by the engine speed, and the width or amplitude by the direction in which the engine is running, the ahead markings, for example, being of greater amplitude. For orders properly executed the pitch and amplitude of the markings correspond with the order given as indicated by the column in which the mark is made. Audible alarms may be provided to operate when the engine movement is in disagreement with the order. The strip-chart is drawn from a roll 53, which may be braked by a band 85 and weight 87, between control rollers 54, 57 to a receiving-roller 58 which may be rotated by a weight 62 suspended from a cord wound round a pulley. The control roller 54 is driven by clockwork 56. The position of the marker is determined by a rack bar 14 engaged by a pinion on the spindle 4 of the telegraph apparatus and carrying a pivoted arm 19 to which the marker 21 is secured. The bar 14 also carries bearings 16 for a shaft 25 having an eccentric 30 which serves to oscillate the marker by a link 34. The shaft 25 is driven from the engine by a pulley 23 and slack belt 22 which is tightened when required by a pulley 37 on a spring-urged sliding bar 39. The bar 39 may be held in the retracted position shown when the order pointer indicates either " stop " or " full speed ahead " by a depending bar 47 the lower end of which has a slot engaging one of two pins 10, 11 on the spindle 4. This bar is released and the belt tightened when the order apparatus is operated. The eccentric 30 is loose and is driven by an eccentrically-mounted tappet 29 engaging one of two pins 31, 32 on the eccentric according to the direction of drive. The throw of the eccentric and the width of the zigzag mark traced are greater when the drive is through the pin 31 than when through the pin 32. An alarm bell 80 has two hammers 82 with pivoted extremities 84. When the apparatus is in the central or " stop " position shown, both members 34 lie in the path of pins 24 on the pulley 23 so that should the engine be driven in either direction one or other of the hammers 82 is operated to give a warning. When the apparatus is displaced to either side to give orders other than " stop, " only one of the members 84 is engaged by the pins 24, and the bell is rung only when the engine is running in a direction disagreeing with the order. To give audible warning when the speed of the engine disagrees with the order, a pump 67 is provided, driven from an eccentric on the shaft 25 and forcing oil from a reservoir 63, carried by the bar 14, through a non-return valve 69 to a cylinder the piston of which, as it rises, successively uncovers apertures 73 through which the oil may escape. The height to which the piston rises thus depends on the rate at which the pump is driven by the engine. The upper end of the piston rod 74 carries a contact pin 70 which, when the engine speed agrees with the order, is between, and out of contact with, two shaped contact-strips 71. Should the engine speed be too great or too small the pin 70 engages one of the strips 71, closing the circuit of an alarm bell.