Patent GB-869541-A (GB)
Title: Improvements in or relating to apparatus for ascertaining mean period of oscillationof a ship
Inventor: DOS HELMUTH
IPC: B63B9/00
Filed: 1957-09-17
Abstract: 869,541. Measuring time intervals. SIEMENS & HALSKE A.G. Sept. 17, 1957, No. 29287/57. Class 37. General.-Apparatus for determining the mean period of oscillation, e.g. rolling or pitching, of a ship wherein a pendulum or gyroscope freely suspended relatively to the vessel is arranged to control the switching on of a pulse counting device which adds the number of deflections of the pendulum or gyroscope with relation to the appropriate axis of the ship over a specific selectable time, and the pendulum or gyroscope is also arranged to control the switching on of a time-measuring device, there being provided a dividing device operatively connected to the pulse counting and time-measuring devices for determining the mean period of oscillation of the ship e.g. in roll or pitch. Construction.-In Fig. 1 a gyro horizon 1 rotating about a vertical axis is universally suspended with its outer gimbal pin lying. axially or transversely of the ship according as roll or pitch time is to be measured, the pin being linked to a shaft 4 oscillating through a friction clutch 5 a moving contact 101 between fixed contacts 102, 103, which contact is connected to a negative current source over normally closed relay contact 232, normally closed change-over contact 252, and normally open contact 212. Fixed contacts 102, 103 are connected to 90 degrees spaced coils 112, 113 of a rotary selector motor 11 returned to a positive current source. The motor has a 2-pole magnetic armature 111 rotatable in 90 degrees steps on shaft 116 by alternate energization of coils 112, 113 through control contacts 114, 115 which are alternately made and broken by the shaft, in series with the negative source through normally open contact 214, and the normally open side of change-over contact 252. Shaft 116 is geared to rotate 180 degrees spaced negatively connected contacts 131, 132 over 18 contact bank 133 of rotary selector switch 13 at a rate of one contact step per quarter turn of armature 111, so that a complete revolution of the contacts 131, 132 corresponds to 18 roll (or pitch) periods of the ship. The 6th and 12th contacts g, n are interconnected and may be coupled through normally open contact 141 of a measurement range switch (not shown) to the 1st contact a. Time is measured by a motor 151 whose armature and field 151, 152 are series connected through resistance 153, normally open contact 202 and normally closed contact 231 in parallel with normally open contact 251 to the current source; part of resistance 153 being shortcircuited by normally closed contact 142 of the measuring range switch. The motor shaft carries a brake disc 158 rotating in the field of a variable current electromagnet excited over a variable resistance adjusting the speed, and is geared to rotate shaft 164 carrying contact 161 connected to positive source over a circular contact path 163 of contact arrangement 16 of which zero contact 162 is connected to negative source through one winding of differential relay 20 whose other winding is connected between negative and positive source over normally closed contact 222. One winding of differential relay 21 is connected between zero contact a of selector switch 13 and positive source, while the other winding is connected to the source over normally closed contact 223. The operating winding of relay 22 is connected between the zero contact a of switch 13 and zero contact 162 of 16, while the holding winding is connected to the source through normally open contact 221 and parallelled normally open contacts 201, 211. A slug relay 27 is connected between zero contact a of switch 13 and positive source, and a braking current can be applied through its windings to the winding 112 of selector motor 11 over normally closed contact 271 and series resistance 28. Shaft 164 also drives a spider 171 connected to positive source carrying three equally spaced contacts which traverse a follow-up switch 17 having a contact ring comprising a zero contact 172 separating and insulated from two insulated 180 degree segmental contacts 173, 174 whose connections are derived from respective slip rings 175, 176, 177; the ring being rotated by shaft 178 driven gearedly together with pointer 191 rotating over scale 192 calibrated in roll period, by a follow-up motor 18 having dual field windings 182 for clockwise and counterclockwise rotation; the respective windings being selectively energized from segments 174, 173 of follow-up switch 17 over slip rings 176, 177 in series with the armature, which is returned. to source negative through normally open contact 233. Contact 172 is connected over slip ring 175 to source negative through one winding of relay 24, whose other winding is energizable to hold over normally open contact 241 and contact 225. Relay 23 is energized over normally closed contacts 242, 203 in parallel with 213, 224 and 253 while relay 25, 26 are energized or energizable over respectively normally closed contact 262 and normally open parallel contacts 226, 261. Zeroizing.-In operation, assuming contacts 131, 132 displaced from a, g or n, contact 161 displaced from contact 162, and contact 171 of the follow-up contact switch 17 in any position; the contacts 141, 142 of the measurement range switch are closed. Relays 20, 21, 25 are energized over contacts 262, 222, 223, while if rotary contact 171 coincides with zero contact 172, relay 24 is energized but if contact 171 lies on segment 173 or 174 it remains de-energized. Contact 252 closes in its off normal position, contact 251 closes, contact 253 opens, contacts 201, 202, 211, 212, 214 close, contacts 203 and 213 open. Motor 15 is energized over contacts 251, 202, 142 ; resistance 153 and rotary selector motor 11 is energized over contacts 252, 214, 114 or 115, and field windings 112 or 113 to drive contacts 131, 132 to a zero position, a, g, or n at which the second cancelling winding of relay 21 and also slug relay 27 are energized; together with field winding 112 over resistance 28 and contact 271. Relay 21 releases, and relay 27 operates after an interval so that the field winding 112 is energized briefly with a braking current to hold in the position shown with contacts 131, 132 in zero position on a, g, or n, until contact 271 opens and contact 214 opens to de-energize the motor. Meanwhile motor 15 drives rotary contact 161 to fixed contact 162 energizing the second cancelling winding of relay 20, which releases to de-energize motor 15 at contact 202, while relay 22 is energized over zero contacts, a, g or n of switch 13. Contacts 222, 223, 225 open, relays 20, 21 are de-energized, as is relay 24 when contact 171 of switch 17 rotates from fixed contact 172, and relay 26 is energized over contact 226 to hold over contact 261. Contacts 201, 211 and holding contact 221 close to hold relay 22 energized, and relay 25 is de-energized at contact 262 on operation of relay 26 to open contacts 251, 252 whereby motors 11 and 15 are arrested at the initial position for measurement. Motor 18 drives the follow-up switch circular member and pointer 191 to conformity with rotary contact 171 until contacts 171, 172 are in contact to re-energize relay 24. Measurement.-As the ship rolls (or pitches) the gyro 1 oscillates, moving contact 101 to close a circuit through contacts 252, 232, 212, and windings 112 or 113 to step rotary selector motor 11 forward by “ turn per change-over of contact 101. Motor 15 is also energized over resistance 153 and contacts 142, 202, 231 and as soon as rotary contact 161 of 16 and rotary contacts 131, 132 leave zero position, relays 20, 21 are de-energized and the operating circuit of relay 22 is broken, together with the holding circuit including contacts 221, 201. 211, so that the relay releases. Relays 20, 21 are re-energized by closure of contacts 222, 223 to close the briefly broken circuits of the selector motor 11 and the time measurement motor 15. The apparatus is arranged so that contacts 131, 132 always reach zero positions a, g or n before rotary contact 161 reaches zero contact 162. At this instant, the second winding of relay 21 is energized to release the relay and break the operating circuit of the stepping rotary selector motor 11, while relay 23 is now energized over contacts 253, 224, 213, 242. Contact 231 opens and de-energizes time-measuring motor 15 so that rotary contact 161 of contact arrangement 16 and rotary contact 171 of follow-up switch 17 also stop. During the period of operation of motor 15, it is assumed that these contacts have rotated e.g. 100 degrees so that contact 171 lies on segment 173, and closure of contact 233 energizes motor 18 to rotate the counterpart of the follow-up switch until contact 171 lies on zero contact 172, the motor 18 circuit is broken, and pointer 19 is rotated through an angle corresponding to that of rotary contacts 161, 171 and to the time of rotation of motor 18, which may be proportionate to the time of roll (or pitch) as shown below. Relay 24 is re-energized on coincidence of contacts 171, 172 and holds over contacts 241, 225. Relay 23 is de-energized at contact 242, to again break the circuit of motor 18 at contact 233, and contact 231 closes to re-energize the circuit of motor 15 to rotate contacts 161 and 171 until 161, 162 are in contact. Both windings of relay 20 are energized over contacts 222 and 161, 162 so that the relay releases, as do relays 21, 25 by reason of closure of contacts 223; 131, 132, 133 and 141; and of the open contact 262. Relay 26 holds over contact 261, and relay 22 is energized over contacts 131, 132, 133 and 161, 162 so that contacts 222, 223, 225 open to reenergize relays 20, 21 and de-energize relay 24. Relay 22 holds over contact 221 so that the initial position for a further measurement is obtained. When contacts 141, 142 of the measurement range switch are closed, the elapsed time of rotation of motor 15 is indicated on dial 19 by