EP0205779A2

EP0205779A2 - Measuring transducer based on the positioning of at least one mechanical revolving element

Info

Publication number: EP0205779A2
Application number: EP86104447A
Authority: EP
Inventors: Vittorio Ponzio
Original assignee: Fabbriche Riunite Misuratori Sacofgas SpA
Current assignee: Fabbriche Riunite Misuratori Sacofgas SpA
Priority date: 1985-04-02
Filing date: 1986-04-01
Publication date: 1986-12-30
Anticipated expiration: 2006-04-01
Also published as: EP0205779B1; ES293322Y; IT1183556B; ES293322U; EP0205779A3; IT8520195A0; DE3679720D1

Abstract

A transducer is described, advantageously appliable to at least a mechanical revolving element (11a... 11h), which makes up the first transducer of the quantity to be measured corresponding to a number and/or fraction of rotations; an example of such type of first transducer can be that of a meter having a predetermined number of revolving elements (11a... 11h) inter-mated for measuring the quantity of fluid or gas delivered. According to the invention, to each revolving element (11a ... 11h) forming the first transducer of the meter, a second transducing element is associated (14a ... 14h), mated to the rotation of the first transducer, the second transducer being a disc (14) with openings (25) positioned according to a predetermined binary code. The second transducer is positioned so as to act as a dividing "nonius" to give a highly accurate measurement.

The signals detected by the two transducers are forwarded to a suitable signal control device (18). The mating between the two transducers is also suitably predisposed.

Description

The present invention refers to a measuring transducer based on the positioning of at least one revolving element.
According to the invention the device can be of great advantage when applied in the measuring of angles, angular displacements, number of rotations and various indications of a mechanical measuring meter for fluid, gas or electric measurements.
At the moment, for instance, the measuring of the number of rotations done by a meter is based chiefly on visual detection. As known, a meter is made up of a group of inter-acting revolving elements, controlled by an operating gear the movement of which is associated to the quantity of fluid or gas passing in a given duct, so to have a correlation between the fluid or gas quantity passing through and the number of rotations, or fractions of rotations done by the revolving elements of the meter. Each revolving element is divided into a predeter mined number of zones, each bearing a number. The revolving elements are mated in such a way that as soon as one terminates a complete turn, it causes the rotation at a predetermined angle of the adjoining one.
A jig placed in a predetermined position allows the visualization of a constant portion of the revolving elements and the visual indication of the numbers or fractions of rotations done by the group of elements. In the known meters no internal transducer is foreseen for the detection of the number of rotations and their transduction in a suitable electric signal, so as to have a record of the fluid or gas consumption on a memory for subsequent elaborations.
Aim of the present invention is thus to carry out a device allowing for the transduction of the measurement pertaining to the number of rotations detected by a meter, into an electrical quantity able to be suitably treated, so as to have the most accurate detection, while still permitting a reliable functioning of the mechanical group and foreseeing a transducer intimately connected to the meter already known.
Said aim is reached by foreseeing that, associated to each revolving element of the meter, thus provided and forming a first transducer, a second mated revolving transducer ·is foreseen, acting as a dividing "nonius", in which the rotations or portions of rotations made by each revolving element and by the second trasnducer are detected as electric signals by appropriate sensors and sent to a control device for these signals.
The special characteristics of the invention will be evident through the specification and drawing enclosed, in which :

Fig. 1 shows a front view of the group to which the transducer according to the invention has been applied;
Fig. 2 shows a detail of the engagement between the two transducers;
Fig. 3 shows a detail of the second transducer according to the invention;
Fig. 4 shows the reciprocal connection of the two transducers subject of the invention and the control devices of the signals detected according to the invention.

With reference to a preferred but not limitative embodiment of the invention, in Fig. 1 we note a meter 10 placed inside a container 9 which is made up of a set of revolving elements lla, 11b...11h suitably mated. As visible from Fig. 1 the revolving elements 11 are mated one to the other by means of gears 21a, 21b, etc. so that at each rotation of the revolving element lla a partial rotation is caused in the adjoining element llb, and so on.
The mating with the gears 21a, 21b...21h is not shown in detail as it is well known. If these revolving elements are divided on the peripheral circumference in ten or more zones, we can have a numerical indication of the number of rotations made by the driving pinion 12. Said driving pinion 12 is in turn connected to a group of gears which can be activated by the passing of a fluid or a gas into a duct. Such a disposition is common to all the meters for instance known for visual detection of the consumption of gas or other energy supplies.
According to the invention, to each revolving element lla, llb... llh, a second transducer formed by a disc 14 used as a first transducer, having openings 25, is associated coupled by means of gears. A disc 14 is shown in detail in Fig. 3.
In Fig. 1 for better clarification only two discs 14 are shown, disc 14c and 14f respectively.
The mating between each disc 14 and the corresponding revolving element 11 takes place by means of gears. Fig. 2 shows an exemplary mating between the revolving element llc attached to a pinion 13c which engages in the gear 15c, the latter rotating integral to the disc-transducer 14c.
Associated to each codifying disc provided with openings, placed according to a predetermined binary code, a detector is provided, for instance photo-sensors 16, which are to detect the disposition of the openings in the disc section passing in front of them. Each detecting element 16 of the codifying disc 14 sends the signal to a suitable control device 18. Also the position of each revolving element 11 is signalled to the control device 18. The control device 18 is in turn connected for instance to a display 20 or to a suitable interface for the dispatching of the detected signal to a suitable centralized device (Fig. 4).
The second transducer 14 formed by a disc provided with openings 25 is a tranducer, or "coder" of the absolute type working as a dividing "nonius" of the traditional devices. This in the aim to be able to detect the small displacements and to obtain a maximum positioning accuracy of the measuring unit.
The mating between the two tranducers 11 and 14 is made in a particular way in the aim to simultaneously obtain the synchronism in the measuring of the passing instant between the data supplied by the faster transducer and the more roughly measuring one.
According to the invention at the moment of assemblying the group incorporating the "nonius" type transducer, the two trans ducers are angularly offset so that the "nonius" transducer is delayed in respect to the corresponding signal of the other transducer. In particular the "nonius" transducer must reach the zero delayed of an interval comprised between 1/5 and 1/10 of a division.
The control circuit 18 of the signal suitably synchronizes among them the signals detected by the two transducers and does not change for instance the signal sent to a display 20 or to a subsequent signal-control device before the other transducer as well has reached the commuting point. In this way the real value remains within the fixed tolerance.
In fact the greater the number of the "nonius" divisions the more accurate the tolerance on the measuring. Such a mechanical disposition allows, in lack of electrical feeding, an indefinite storage of the detected data also in the case of measuring variations. The two transducers keep the reached positions.

Claims

₁. A measuring transducer based on the positioning of at least one revolving element, characterized in that it comprises a first transducer, formed by said mechanical revolving element lla...llh to which a second revolving mated transducer 14a...14h is associated, acting as "nonius" comprising a multiple number of openings placed according to a predetermined code and to the desired limit of accuracy, the position of the two transducers being detected by sensors 16a... 16h which send the signal to a control device 18.

2. A tranducer according to claim 1, characterized in that the mating between the first and the second transducer takes place in such a way that the "nonius" transducer 14a...14h is delayed with respect to the zero of the first transducer.

3. A device according to claim 1, characterized in that the delay is comprised in a 1/5 and 1/10 of division.

4. A transducer according to claim 1, characterized in that the control device 18 comprises a synchronizing device of the detected signals.

5. A device according to claim 4, characterized in that the synchronizing device foresees a coinciding and interpreting circuit which controls by addition or substraction the data supplied by the two sensors so as to supply at the output the measurement reached in the required tolerance.

6. A transducer as per enclosed specification and drawings.