GB1563642A

GB1563642A - Alternating electronic pulse emitters

Info

Publication number: GB1563642A
Application number: GB24839/77A
Authority: GB
Original assignee: Ljungmans Verkstader AB
Current assignee: Wayne Fueling Systems Sweden AB
Priority date: 1976-06-30
Filing date: 1977-06-14
Publication date: 1980-03-26
Also published as: FI63126B; NO772127L; SE400002B; SE7607443L; NO144028C; FI63126C; DK291377A; DE2722844C2; DE2722844A1; NO144028B; FI771935A; DK150837C; DK150837B

Description

(54) IMPROVEMENTS IN OR RELATING TO ALTERNATING ELECTRONIC PULSE EMITTERS (71) We, AKTIEBOLAGET LJUNG MANS VERKSTADER, a company duly organised under the laws of Sweden, of Limhamnsvagen 109, 216 13 Malmö, Sweden, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a pulse emitter of the type comprising a first screen for movement relative to a first lightemitting means, and a photosensitive device cooperating with said means and coupled into an electronic circuit with an output for digital pulses.

Photoelectric pulse emitters are utilized in many contexts for powering binary counters for indicating quantities, such as weight and volume, measured by means of measurement devices. Moreover, these counters are also used for indicating the price of the measured quantity. However, the pulse emitters are mechanically coupled to the measurement devices by means of couplings which transmit vibrations from driving means such as pumps, pistons. motors and from ineffective return feed locking mechanisms to the pulse emitter, these vibrations in, for example, de-energization of the pulse emitter, causing the pulse emitter to pass its on and off positions and thereby to continue to emit pulses, with resultant incorrect indications on the counter.

The object of the present invention is to provide a pulse emitter which goes a long way to eliminating this problem.

According to the invention. this object has been achieved in that a second screen is spaced from the first screen for movement relative to a second light-emitting means and a second photosensitive device cooperating therewith, and the electronic circuit is designed such that the passage. through the second screen of light from the second light-emitting means to the second photosensitive device occasions the inactivation of the second light-emitting means and the activation of the first light emitting means by means of the pulse from said output, and the prevention of the passage of light to the first photosensitive device from the first light-emitting means by the first screen occasions activation of the second lightemitting means and inactivation of the first light-emitting means by means of the pulse from said output.

One embodiment of the invention will be described in greater detail hereinbelow with reference to the accompanying drawings, of which Figure 1 shows a perforated disc for a pulse emitter according to the invention, and Figure 2 is a circuit diagram for the pulse emitter.

For simplicity's sake, it will be supposed that the described embodiment is intended for connection to a flow meter in a liquid dispensing system with a pump, in which case the pulses from the pulse emitter can be utilized for indicating the volume and/or price of the liquid dispensed by the pump.

To this end, the pulse emitter comprises a circular disc 1 of opaque material, the disc being intended to be fixed, by means of a centre opening 2, on a shaft (not shown) which is rotatable by means of the flow meter. The disc 1, has. in a known manner, a row of identical, equidistant holes 3a coaxial with the centre opening and defined by spokes 3b in the disc. The disc is intended for insertion in a photoelectrical sensor system. that is to say between a fixed light-emitting element and a fixed photosensitive element so that the row of holes lies on a level with these elements. In the described emhodiment, the holes 3a are quadrilateral and taper towards the centre of the disc.

The disc 1 has a second row of identical, quadrilateral and equidistant holes 4a defined by spokes 4b in the disc. This second row of holes is concentric with the first row of holes. In the illustrated embodiment, the second row of holes is disposed inwardly of the first row and its holes 4a are of substantially equal width and equal in number to the holes 3a of the first row. The holes 4a are narrower than the holes 3a seen in the circumferential direction of the disc. The axes of symmetry in the radial direction for each hole 3a and the hole 4a located inwardly of each hole 3a lie on one and the same disc radius.

The second row of holes is, like the first row of holes, associated with a photoelectric sensor system, that is to say, arranged to be placed between, and on a level with, a fixed light-emitting element and a fixed photosensitive element.

In Figure 2 is shown a circuit diagram for the pulse emitter, in which the rows of holes are represented by the broken lines 3 and 4.

The light-emitting elements, for example, a light diode, associated with each row of holes are designated 5 and 6. respectively.

The corresponding photosensitive elements 7 and 8, respectively, for example, a photo diode, transistor or resistor form inputs to an amplifier 9 of a per se known type, for example, SIEMENS TCA 105, which has a digital direct output 10 and digital inverted output 11. The direct output 10, whence the pulses are transmitted to the volume/price indicator. is connected by means of a conductor 12, to the light-emitting element 5, and the inverted output 11 is connected by means of a conductor 13, to the lightemitting element 6. These light-emitting elements 5 and 6 are supplied with current from a d.c. voltage source 14.

With the photosensitive element 7 being of the type which is sensitive to the transition from light to darkness, that is to say from a hole 3a to a spoke 3b; and with the photosensitive element 8 being of the type which is sensitive to the transition from darkness to light, that is to say from a spoke 4b to a hole 4a, the function of the pulse emitter will be immediately apparent and is as follows: When the light sweeps from a hole 3a to a spoke 3b, the direct output 10 changes from state 0 to state 1. the resultant pulse inactivating the light-emitting element 5 via the conductor 12. The inverted output 11 then undergoes a change of state from 1 to 0 and activates, via the conductor 13. the light-emitting element 6.The inactivated state of the element 5 and the activated state of the element 6 last until the light from the light-emitting element 6 strikes the follow ing - in the direction of rotation of the disc 1 - hole 4a in the inner hole row, the outputs 10 and 11 undergoing changes of state from 1 to 0 and 0 to 1, respectively, so that the element 5 is activated and the element 6 is inactivated until the light from the lightemitting element 5 associated with the outer hole row sweeps the transition from a hole 3a to a spoke 3b.

The above operational description shows immediately that if, after the switching-off of the pump, the disc 1 picks up vibrations from, for example, the pump motor so that it rotates in its plane back and forth about its centre axis it can, once the light from the element 5 has swept from a hole 3a to the immediately adjacent spoke 3b, rotate the sector a (that is to say, the sector defined by a spoke 4b) without any pulse being obtained on the direct output 10. Similarly, the disc can, once the light from the element 6 has swept from a spoke 4b to the immediately adjacent hole 4a, rotate in the sector ss (that is to say, the sector defined by the lateral extremities of a hole 3a) without any signal being obtained on the direct output 10.

The pulse emitter according to the invention is, in actual fact, an effective complement to existing return stops, that is to say, stops whose purpose is to prevent disc rotation in a direction opposite to that intended, thereby to prevent incorrect indication.

Naturally, the invention may be modified in many ways without departing from its spirit and scope. Thus, the disc can consist of a translucent disc with blacked-out portions instead of spokes for realizing the opaque fields. Translucent and opaque fields arranged in succession are often called screens, as is the case in the appended claims. Naturally, the screens need not be circular, nor need they be provided on a circular disc. They could equally well be elongated and be disposed on a strip which moves past the photoelectric sensor elements.

WHAT WE CLAIM IS: 1. A pulse emitter comprising a first screen for movement relative to a first light-emitting means, and a photosensitive device co-operating with said means and coupled into an electronic circuit with an output for digital pulses. wherein a second screen is spaced from the first screen for movement relative to a second lightemitting means and a second photosensitive device co-operating therewith, and the electronic circuit is designed such that the passage, through the second screen, of light from the second light-emitting means to the second photosensitive device occasions the inactivation of the second light-emitting means and the activation of the first lightemitting means by means of the pulse from

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. of the disc. The disc 1 has a second row of identical, quadrilateral and equidistant holes 4a defined by spokes 4b in the disc. This second row of holes is concentric with the first row of holes. In the illustrated embodiment, the second row of holes is disposed inwardly of the first row and its holes 4a are of substantially equal width and equal in number to the holes 3a of the first row. The holes 4a are narrower than the holes 3a seen in the circumferential direction of the disc. The axes of symmetry in the radial direction for each hole 3a and the hole 4a located inwardly of each hole 3a lie on one and the same disc radius. The second row of holes is, like the first row of holes, associated with a photoelectric sensor system, that is to say, arranged to be placed between, and on a level with, a fixed light-emitting element and a fixed photosensitive element. In Figure 2 is shown a circuit diagram for the pulse emitter, in which the rows of holes are represented by the broken lines 3 and 4. The light-emitting elements, for example, a light diode, associated with each row of holes are designated 5 and 6. respectively. The corresponding photosensitive elements 7 and 8, respectively, for example, a photo diode, transistor or resistor form inputs to an amplifier 9 of a per se known type, for example, SIEMENS TCA 105, which has a digital direct output 10 and digital inverted output 11. The direct output 10, whence the pulses are transmitted to the volume/price indicator. is connected by means of a conductor 12, to the light-emitting element 5, and the inverted output 11 is connected by means of a conductor 13, to the lightemitting element 6. These light-emitting elements 5 and 6 are supplied with current from a d.c. voltage source 14. With the photosensitive element 7 being of the type which is sensitive to the transition from light to darkness, that is to say from a hole 3a to a spoke 3b; and with the photosensitive element 8 being of the type which is sensitive to the transition from darkness to light, that is to say from a spoke 4b to a hole 4a, the function of the pulse emitter will be immediately apparent and is as follows: When the light sweeps from a hole 3a to a spoke 3b, the direct output 10 changes from state 0 to state 1. the resultant pulse inactivating the light-emitting element 5 via the conductor 12. The inverted output 11 then undergoes a change of state from 1 to 0 and activates, via the conductor 13. the light-emitting element 6.The inactivated state of the element 5 and the activated state of the element 6 last until the light from the light-emitting element 6 strikes the follow ing - in the direction of rotation of the disc 1 - hole 4a in the inner hole row, the outputs 10 and 11 undergoing changes of state from 1 to 0 and 0 to 1, respectively, so that the element 5 is activated and the element 6 is inactivated until the light from the lightemitting element 5 associated with the outer hole row sweeps the transition from a hole 3a to a spoke 3b. The above operational description shows immediately that if, after the switching-off of the pump, the disc 1 picks up vibrations from, for example, the pump motor so that it rotates in its plane back and forth about its centre axis it can, once the light from the element 5 has swept from a hole 3a to the immediately adjacent spoke 3b, rotate the sector a (that is to say, the sector defined by a spoke 4b) without any pulse being obtained on the direct output 10. Similarly, the disc can, once the light from the element 6 has swept from a spoke 4b to the immediately adjacent hole 4a, rotate in the sector ss (that is to say, the sector defined by the lateral extremities of a hole 3a) without any signal being obtained on the direct output 10. The pulse emitter according to the invention is, in actual fact, an effective complement to existing return stops, that is to say, stops whose purpose is to prevent disc rotation in a direction opposite to that intended, thereby to prevent incorrect indication. Naturally, the invention may be modified in many ways without departing from its spirit and scope. Thus, the disc can consist of a translucent disc with blacked-out portions instead of spokes for realizing the opaque fields. Translucent and opaque fields arranged in succession are often called screens, as is the case in the appended claims. Naturally, the screens need not be circular, nor need they be provided on a circular disc. They could equally well be elongated and be disposed on a strip which moves past the photoelectric sensor elements. WHAT WE CLAIM IS:

1. A pulse emitter comprising a first screen for movement relative to a first light-emitting means, and a photosensitive device co-operating with said means and coupled into an electronic circuit with an output for digital pulses. wherein a second screen is spaced from the first screen for movement relative to a second lightemitting means and a second photosensitive device co-operating therewith, and the electronic circuit is designed such that the passage, through the second screen, of light from the second light-emitting means to the second photosensitive device occasions the inactivation of the second light-emitting means and the activation of the first lightemitting means by means of the pulse from

said output, and the prevention of the passage of light to the first photosensitive device from the first light-emitting means by the first screen occasions activation of the second light-emitting means and inactivation of the first light-emitting means by means of the pulse from said output.

2. Pulse emitter according to Claim 1, wherein the screens are concentric, and the first screen has identical, equidistant translucent fields and the second screen has identical, equidistant translucent fields of lesser width, seen in the circumferential direction, than that of the translucent fields of the first screen, the translucent fields of the second screen lying in radial register with translucent fields of the first screen.

3. Pulse emitter according to claim 1 or 2, wherein the first photsensitive device is operative to respond to the transition from light to darkness, and the second photosensitive device is operative to respond to the transition from darkness to light.

4. A pulse emitter comprising a first screen for movement relative to a first light-emitting means, and a photosensitive device cooperating with said means and coupled into an electronic circuit with an output for digital pulses, substantially as hereinbefore described with reference to the accompanying drawing.