Patent GB-857241-A (GB)
Title: Device for electrically transmitting and remotely registering the indications of a measuring instrument
IPC: G01G23/18
Filed: 1957-05-29
Abstract: 857,241. Electric selective signalling systems. KOOPERATIVA FORBUNDET EKONOMISK FORENING. May 29, 1957 [March 18, 1957; May 29, 1958], No. 17109/57. Class 40 (1). The invention relates to apparatus for transmitting to a distance the readings of measuring devices such as weighing machines, means being described for registering the correct digit if two adjacent digits in the same order are both sensed. As described, for a weighing machine, Figs. 1, 2, with a capacity of 100 kg., a scale ring 1 is graduated by divisions of 0.1 kg. and a pointer 3 mounted on a rotatable shaft 4 takes up a position corresponding to the weight in question. Mounted on the other end of the shaft 4 is a sensing disc 5 provided with holes 6 spaced apart by a distance equal to the kilogrammes division on the scale 1 and arranged to sense the 0.1 kg. divisions, pins 7 spaced apart by a distance equal to 10 kg. on the scale and arranged to sense the 1 kg. divisions, and bent bars 8 whose number equals the number of 10 kg. divisions. A displaceable holder 9 is mounted opposite the sensing disc 5 and is normally disengaged, but on energization of a magnet DR is displaced against the bias of a spring 16 so that (a) pin 10 (for tenths) come into engagement with the holes 6, the spacing of the holes being on the vernier principle of ten pins for nine holes, (b) one or more of pins 11 (for units) contact one of the pins 7 (c) one, two or three of the pins 12 (for tens) contact a bent bar 8. Each of the pins on the holder 9 co-operates with a pair of contact springs 17, the contact springs for the pins 10 being normally closed so that those contacts the pins 10 of which do not enter holes are open, while the contact springs for the pins 11 and 12 are normally open, so that those contacts the pins 11 and 12 of which stand against their corresponding projections are closed. A common wire 18 is connected to positive potential. In operation, with the main switch HS, Fig. 5, on, depression of the start button St energizes a relay HR which holds and causes the relay DR to be energized, thereby displacing the holder 9 towards the sensing disc 5 and starting a motor M which drives a contact arm m counterclockwise over contacts 1-7. When the arm m reaches the contact 1, a relay AE is energized and holds, the closure of its contact ae2 connecting positive to the line 18, Fig. 1. If not more than one of the contacts 17 in each decade is closed, then corresponding relays from the relays A-J for tenths, the relays K-T for units, and the relays U-AA for tens are energized. However, if two consecutive tenths contacts are closed, the relay contacts a1-j1 ensure that only the relay corresponding to the lower digit is energized. If two consecutive units contacts are closed, the lower digit is required if the tenths digit is high and the higher digit if the tenths digit is low. Thus, if the tenths digit is high the ten contacts k2-t2 ensure that the higher units digit is ineffective, but if the tenths digit low, lying in the range 0-4, the network of contacts a4-e4, l4-t4, k4-s4 effects energization of a magnet AD, the change-over contacts of this magnet ensuring that the higher units digit is effective. In a substantially similar manner, if two consecutive tens contacts are closed, the correct one will be chosen depending on the value of the units digit. An additional relay KK is energized over the contact t5 when the relay K is energized, but the relay T is not, but is not energized when both relays T and K are energized so that the lower digit 9 and not 0 is selected, but the unit digit 0 is selected if the tenths digit is of low value since the contacts t6, k5 close to connect the relay KK in parallel with magnet AD. If the hundreds contact is closed and the relays A, KK, U have been energized to close their contacts a5, kk2, u5, that is, if the weight is 100 kg., then the relay AB is energized. When the contact arm m reaches the contact 2, a relay AF is energized to open contact af2, disconnecting the magnet DR so that the holder 9 returns to its original position, to close contact af3 to keep the motor M energized, to open contact af4 which disconnects the line 18, Fig. 1, and to close the contact af5 to maintain the relay AB if this relay has been energized. When the contact arm m reaches the contact 3, current is sent via the contact ab2 over an output line 0 if the weight is less than 100 kg., and via the contact ab3 to an output line 1 if the weight is 100 kg. When the contact arm m reaches the contact 4 current is sent to the contacts u1-aa1 &c. to pass the tens digit to the output. The contacts 5, 6 similarly arrange for the units and tenths digits to pass to the output. The output lines may pass to an adding machine which is not described in detail, and when the contact 7 is reached by the arm m, the number passed to the adding machine is recorded and a relay ÍR opens a contact Ír to de-energize the system. The sensing means may comprise sources of light and photocells. Specification 845,545 is referred to.