DE7823595U1 - DEVICE FOR INDEPENDENT SPEED MEASUREMENT WITH ANALOGUE AND NUMERICAL DISPLAY - Google Patents

Description

The present invention relates to devices for measuring speed, which make it possible to display the speed of rotation of a rotating element and in particular those in which the information (speed) is supplied in duplicate.

Such devices are known, they allow when the Measuring scale is very wide to get a more accurate measured value with the help of a second display device, which is the classic Display way, namely the pointer, operated. This second facility can work in the same way - for example, a rotating disk or a second needle that is on the same dial, but located in front of a second graduation scale - or numerically. In this case, the device is a counter with one or more mechanical or electromagnetic drums to be attached. The representation of the result by a numerical method is the most interesting as it allows the two modes of display to be most clearly distinguished; meanwhile it had a significant disadvantage to this day: it would, in order to be able to be started, an external energy source is required, since it is an electromagnetic drum counter acts: in this case one would actually have to have an electronic drive system for these drums, or a counter with mechanical ones Attach drums: the energy available at the measuring system would in this case be too weak to drive the counter alone, and it would prove necessary to add a servo mechanism to provide propulsion.

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Compared to the previous technology, the present system has the advantage of being completely independent and so on

there is no need for an external energy source;

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The invention is described in more detail below with reference to an exemplary embodiment shown in the drawing explained.

It shows:

1 shows a diagrammatic representation of the embodiment in the scheme;

FIG. 2 shows a plan view of the display of the embodiment according to FIG. 1.

Figure 1 shows a three-phase alternator 1, connected to the drive shaft 2 of the control element, a three-phase motor 3 from said alternator 1 is fed, synchronizes itself and drives a measuring magnet at a speed, which is proportional to the speed of the alternator 1. The three-phase motor 3 is designed so that j that it has an excellent, synchronous moment, especially at very low speeds, thanks to the choice of powerful magnets with a small volume, which reduces the inertia involved

entails, also with regard to the structure of the rotor, in particular what the angle of the free space of the magnet with respect to the partial hysteresis (approximately 90 °) as well as the respective relationships between the sizes of the synchronization magnet, the partial hysteresis and their air gaps.

A disk (or a bell) 5 made of non-magnetic conductor material is arranged coaxially in the vicinity of the magnet 4 and is driven by eddy currents (Foucault currents). The driving torque is proportional to the speed of the measuring element and balanced by the return force of a counteracting spiral spring 6, which is mounted on the axis 7 of the disc 5. Said axis 7 also carries a pointer 8, which is divided into degrees in front of a Moving dial. In order to obtain the greatest possible energy available in the transmission through the eddy currents, one chooses magnets, which have a high induction and a weak temperature coefficient, which makes one non-magnetic conductor material can use, which has a higher temperature coefficient and a lower specific line resistance, to increase the drive torque.

A toothed wheel 10 is mounted on the axis between these two elements and is coaxial with the disk 5 and with the spiral spring 6 is in engagement with its reduction gear 11, which in turn engages in a pinion that with the axis 13 of a Counter 14 is firmly connected to several drums with a very low section modulus, which numerically indicates the speed indicates.

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The counter 14 has at least two drums. A drum 14a is driven directly by the measuring kinematics; it is thus in continuous rotation and graded from 0-9, with each Number represents a unit. On the right-hand side of the said drum, a further division can be added to the To ensure reading of the subdivisions of the units. Each time the tenth unit passes, the drum 14a drives a second drum 14b via a suitable gear mechanism with a quick step through, each number of which represents 10 units. The drum 14b can in turn, if it is necessary to drive another drum.

To get a counter that has a very weak drive torque needed, the gear mechanism or the gearbox is very light and mounted inside the drums, which is also are very easily trained. The axle rests in bearing shells with a capstone made of an artificial ruby; each end of the axis of the drum and the transmission pinion is individually rotatable.

The tooth profiles themselves are designed in such a way that they transmit movement ensure with low friction.

Claims (1)

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Hunter Claim : Apparatus for measuring speed using eddy currents, giving an indication of the speed of rotation of a rotating element allowed in duplicate, characterized in that it has a drive working with eddy currents, by means of whose drive torque an axle can be driven, which at the same time carries a needle for the analogue speed display and a gear, which by means of a suitable Reduction gear with a mechanical counter very low moment of resistance, which provides a numerical speed display.