EP0078787B1 - Electromechanical counter for continuous numerical adding or substracting - Google Patents

Description

The invention relates to an electromechanical counter for the continuous numerical addition or subtraction of electrical impulses, consisting of one or more series-connected digit rollers, each of which can be driven by the previous one, the initial digit roller carrying a gear wheel; which alternately engage the projections arranged in the end region of a switch armature connected to an electrical coil which is effective in the force field of a permanent magnet system and thereby gradually set the initial digit roller in rotation.

Electromechanical counters are known to be built and operated on the basis and technology of a relay. A coil wound around a soft iron core is used for this. The coil through which the electric current flows generates a magnetic field which attracts an iron plate articulated in the immediate vicinity of the soft iron core. A corresponding mechanism is connected to this plate, which converts the pivoting movement of the plate into a rotary movement of the numerical roller. After the current flow in the coil has ceased, the mechanism is returned to its rest position by a spring which has been tensioned by the pivoting movement of the plate.

DE-B 1 032 952 shows a device with a moving coil working in a bomogeneous magnetic field, wherein the moving coil can be used to drive the armature of a counter.

FR-A 2 152 387 also discloses a magnet system and a coil for driving the armature of a counter, but with large air gaps between the coil and the magnet.

Known counting relays require a high level of mechanical effort for low-friction and precise storage of all moving parts such as: pawls, roll anchors, magnetic anchors, and any deflection lever mechanisms. Furthermore, the counting frequency is limited by the inertia resistance of all these metal parts, so that, if necessary, this can only be increased by increased return springs and the associated higher excitation power. However, this has the consequence that the counter must be operated with a multiple of the energy than would be necessary for the actual advancement. To increase the counting sequence, i.e. To achieve shorter pull-in and fall times, a higher acceleration of the moving masses is necessary, which can only be achieved by increasing the acting forces. This is made more difficult by the fact that the force with which the magnet armature is pulled towards the coil core or into the coil represents a function of the magnetic air gap, ie the greater the magnetically effective air gap, the smaller the attraction force with constant coil excitation and conversely reaches a maximum when the air gap becomes zero.

• Nach dem dynamischen Grundgesetz
• F (Kraft) = m (Masse). a (Beschleunigung)
• ist, da die Masse konstant bleibt, die Beschleunigung nur von der Kraft (F) abhängig.

In the specific case, there is a relatively slow increase in force due to the distance that the magnet armature continuously reduces due to the movement towards the core.

• According to the dynamic constitution
• F (force) = m (mass). a (acceleration)
• Since the mass remains constant, the acceleration only depends on the force (F).

• FIG1/25

umgekehrt proportional zum Luftspalt ändert, also in der Anfangsphase des Ankeranzuges sehr schlecht ist. Da aber die größte Anzugskraft in der Endphase der Ankerbewegung auftritt, zu einer Zeit also, zu der der Schaltvorgang der Ziffernrolle schon beendet ist, wird die nunmehr umgesetzte Energie wieder nicht nutzbringend verwendet, sondern zusammen mit der kinetischen Energie des Ankers an seinem Endanschlag in Wärme umgesetzt oder zur Deformation des Materials verwendet, was einen schlechten Wirkungsgrad ergibt.Then: a = k. F if one uses (k) as a constant for the reciprocal of the mass. Since the force (F) is a minimum in the initial phase of the anchor suit, the acceleration (a) at the same time is also low. But since the speed (v) is also proportional to the acceleration (a) (v = a. T), it will only gradually increase with increasing force. This means that the efficiency (η) of the counter

• FIG1 / 25

changes inversely proportional to the air gap, i.e. is very bad in the initial phase of the anchor suit. However, since the greatest pulling force occurs in the end phase of the armature movement, i.e. at a time when the switching process of the numerical roller has already ended, the energy now converted is not used again, but together with the kinetic energy of the armature at its end stop in heat implemented or used to deform the material, which results in poor efficiency.

After the current in the excitation coil of the magnet system has ceased, the magnetization of the iron causes a remanence, which is noticeable in that the response values of the counting relay are shifted. The response point in the following switching process is achieved by a significantly lower current flow, since the induced magnetic field builds up on the remanent field. This residual magnetism can be so strong that an exact fall of the magnet armature is no longer guaranteed, or it even sticks to the magnet core. In any case, a considerable effort is required to compensate for these disadvantages, if one does not want to worsen the electrical efficiency even more by further enlarging the effective air gap.

It is also known to drive counters with stepper motors, the latching positions of the permanent magnetic rotor being used for the mechanical positioning of the digit rollers. However, using a stepper motor does not require one Insignificant effort for the motor itself, because it has to be manufactured very precisely due to its functional principle and also has to be coupled to the dial roller mechanism by means of a gear mechanism. On the other hand, the electrical control of the stepper motor requires precise single-phase or multi-phase pulse sequences, which can often only be achieved by complex electronic special circuits. However, since this control electronics also consumes electrical energy, the relatively good efficiency of a stepper motor is often deteriorated.

The invention has for its object to provide a drive for an electromechanical roller counter, which avoids the disadvantages of the known drives and should be much simpler in construction compared to them. In particular, the intended drive should have a high switching speed and a high electrical efficiency. Furthermore, there is a need to enable the counter to be controlled by means of simple current pulses which do not require electronic preparation, with magnetic remanence and sticking of the magnetically attracted part being avoided.

The invention solves this problem in a simple manner in that the coil is arranged coaxially in the force field between permanent magnet systems opposite one another with the same polarity in their force field, that the coil experiences a deflection in the axial direction of the permanent magnet systems when electrical current flows through from one magnet system to the other, and that the coil and permanent magnet systems are disc-shaped.

Since the force which the coil transmits to the switch armature is approximately the same over the entire deflection range due to the coil geometry, the position of the switching point of the numerical roller with respect to the path is insignificant, so that larger tolerances can be permitted. While one has to take care in the construction of the magnet armature counting relay to put the switching point, or the point of the greatest power output in the already short area just before the end stop, the magnetodynamic drive according to the invention has a relatively large path available, which due to the linear force distribution for switching the counter can be fully used. The geometry of the coil can also be adapted to the respective requirements. However, the universal electrical adaptability of the coil to existing power sources represents a significant advantage. Expensive adaptation and interface devices can therefore be dispensed with, which contributes significantly to making a system cheaper.

Because the coil according to the invention does not contain an iron core, the induction (B) is also not dependent on a relative permeability (U _rel that changes with the field strength (H), as the equation shows. B = U _rel . U _o . H. (U _o ) represents the absolute permeability of the empty space.

• F=_B.₁.1

The force that a current-carrying coil generates in the magnetic field depends solely on the induction (B) of the magnetic field in the air gap, the length of the conductor (1) or the number of turns and the current (I) flowing through the coil.

• F = _{B. 1} .1

This means that the force (F) for a given induction (B) depends only on the number of ampere turns. If this product remains constant, the current and the number of turns can be changed depending on each other (low number of turns - high current, high number of turns low current). This makes it possible to select a coil that has minimal self-induction, even for certain applications. As a result, the damping can be brought to an optimum level for each system, which also allows the switching sequence speed to be influenced.

Advantageous developments of the invention are contained in the subclaims.

In the drawing, the invention is illustrated in more detail using exemplary embodiments. 1 shows the object according to the invention with a pivotably mounted switching armature and FIG. 2 with a switching armature designed as a slide.

The electromechanical counter according to the invention shown in FIG. 1 consists of a plurality of numerical rollers 2, 3 seated on a shaft 1, each of which can be driven by the preceding numerical roller via corresponding drive gearwheels. The initial digit roll 3 carries a gear wheel 4, in the number pieces of which alternately engage the tooth-shaped ends 5, 6 of a U-shaped switch armature 7, which can be pivoted about a horizontal axis 8. This alternating engagement of the tooth ends 5, 6 in the tooth gaps of the gear wheel 4 results in a step-by-step advance of the digit roller 3 in the direction of the arrow 9.

According to the invention, the switch armature 7 carries on the side facing away from the tooth ends 5, 6 on an arm 10 an electrical, wire-wound coil 11, which has the shape of a cylindrical disc on the outside and lies in a common plane with the axis 8. The coil 11 is arranged in the magnetic field of two permanent magnets 12, 13 and, depending on the direction of the electrical current flowing through it, is either attracted or repelled by the magnet 12 or the magnet 13. This movement of the coil 11 in the magnetic field of the magnets 12, 13 is transmitted to the switch armature 7 for the purpose of advancing the digit rolls 2, 3.

So that the coil 11 can return to its starting position after the current flow has ended, a spring 14 acts on the armature 7.

2, the rotary movement of the armature 7 has been replaced by a linear movement. The shift armature 15 driving the gear wheel is designed as a slide, to which the coil 11 is fastened directly or via a force-locking mechanism. It is mounted with low friction in a corresponding guide and can be returned to the respective starting position by a spring 14 acting on it. The coil 11 itself is in turn in the effective air gap between r permanent magnets 12.13 arranged with the same poles to one another, which form an inhomogeneous magnetic field. In principle, a single magnet would also be sufficient, but the efficiency increases many times over when using two magnet systems.

Since the direction of movement of the coil 11 depends on the direction of the current flowing through it, the required restoring force can also be obtained via a change in direction of the coil current instead of via a mechanical spring. For example, the counter can be advanced by the chronological sequence of a positive and negative pulse. It is not important whether the two pulses follow one another directly or act on the counter at any time interval. Because of these properties, a bistable mode of operation of the counter can also be achieved, the counter being incremented by a number irrespective of the direction of movement of the coil 11 if alternating positive and negative pulses are present for actuation. It follows that only a current direction inverse with respect to the current direction of the previous pulse can cause a counting process. This operating mode can, for example, enable the evaluation of information from logic circuits and machine controls to be carried out more economically. Operation of the meter according to the invention with alternating current can also be realized, which appears to be particularly advantageous when the system is to be operated in the vicinity of its mechanical cutoff frequency.

Due to the extremely low energy requirement of the counter drive system according to the invention, a counter is hereby available which is ideal for use in battery-powered devices such as Counter heat quantity, as well as suitable for operation from solar batteries.

Claims (4)

1. Electromechanical counting unit for continuous numerical addition or subtraction of electrical impulses, consisting of one or several successively arranged number rolls (2,3), of which each individual one can be driven by the preceding one, wherein the starter number roll (3) carries a gear wheel (4) against which alternately engage projections (5,6) arranged in the end region of a switching armature (7) connected to an electrically operated coil (11) in the force field of a permanent magnet system (12,13) and thereby displace the starter number roll (3) into stepwise rotation, characterised in that the coil (11) is arranged in the effective air gap between similar pole oppositely lying permanent magnet systems (12, 13) coaxially in their force field, that the coil (11) on electrical current flowing through it undergoes a displacement in the axial direction of the permanent magnet system from the one magnet system to the other, and that the coil (11) and the permanent magnet systems (12,13) are constructed in the shape of discs.

2. Counting unit according to claim 1 characterised in that the disc-shaped coil (11) has the form of an inner hollow cylindrical disc.

3. Counting unit according to one of claims 1 and 2, characterised in that the coil (11) after displacement by means of the electromotive force can be pulled back into starting position by a spring (14) engaging in known fashion on the switching armature (7, 15).

4. Counting unit according to one of claims 1 and 2 characterised in that the coil (11) can be returned into the starting position by a control current of reversed polarity.

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