DE186634C - - Google Patents

Description

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PATENT LETTERING

- JV * 186634 - CLASS 21 e, GROUP

Changeover terminal. Patented in the German Empire on December 4, 1906.

In many cases, when measuring any electrical quantity, the required for this can be achieved Measuring instrument can be brought into readiness for measurement by simple manipulations. But it is also not uncommon that several such simple manipulations in a very specific order for operation of a measuring instrument are necessary. In such cases, errors are unpleasant Of course, there are no consequences for the instrument, especially for inexperienced people rare. For example, when using a moving coil ohmmeter you have several Switch settings to be taken into account and shortly before the acceptance of the measured Resistance to depress a key. But just this last caution that for The protection of the instrument is of the greatest importance, is most easily forgotten.

The mechanical arrangement of this instrument, which is derived from the term "moving coil ohmmeter" is called assuming known. It should only be pointed out here that the counterforce the coil springs known from the moving coil in the imaginary ohmmeter continuously in this way are very excited that they have left the movable coil to its own devices two or three times would rotate around their axis. The mechanical structure makes this impossible; however, if with the instrument Resistance measurements are made and the measured resistance is removed from the terminals, so the previously snaps Coil twisted by the measuring current with a sharp jerk back to its rest position. In order to avoid this, the already mentioned button is attached, by means of which on Instead of the measured resistance, another resistance inside the instrument is placed on the terminals. This device then prevents the moving coil from returning too quickly to the rest position and the hard stop does not occur.

As mentioned above, this is a precautionary measure easily forgotten and the instrument then suffers damage. It would therefore be extremely beneficial if by decreasing the measured resistance from the instrument terminals, the switch-on the equivalent or calming resistance could take place automatically, and this is the determination of the following described invention.

The subject matter of the invention shown in FIG. 1 of the accompanying drawing appears externally as one of the known nut clamps covered with insulating material; the internal structure is as follows:

The threaded bolt α is tightened with the head and the nut c in the instrument wall w. A hole passing through the axis of the bolt α is lined with a hard rubber tube b , into the cavity of which the metal pin d is rotatably inserted. At its upper end it carries a crutch e and the lower end protrudes beyond the bolt head α . The upper part of the bolt α carries the terminal nut, which consists of the actual metal nut f and a hard rubber body i encompassing it.

Claims (3)

In this hard rubber body ζ there is a chamber k in which the crutch e of the metal pin d has a certain amount of leeway; In one corner of the chamber k there is a metal pin g which is firmly connected to the nut /. A hard rubber cover h, which shoots the gill nut outwards, is placed over the chamber k, in which the parts mentioned are located. ίο At the lower end of the pin d is a contact spring or. Sliding spring m, which is carried by any fastening piece and to which the end of a resistor is to be connected. If you now turn the terminal nut in the clockwise direction, corresponding to the clamping of a wire, the crutch e lies against the hard rubber wall of the chamber k. The pin d is therefore also rotated as long as the movement of the nut continues in said direction, but it remains isolated from the nut f. If the direction of movement of the nut is reversed, which is necessary to remove a previously tensioned wire, the crutch e rests firmly against the pin g, making the metal nut f metallic with the pin d over the crutch e and the pin g connected is. Let such a switchover clamp and an ordinary clamp be attached to one of the instruments previously described (see FIG. 2). A line goes from the ordinary terminal to a resistor w of a certain size and from this a connection to the contact spring m of the switchover terminal. As a result of this arrangement, the crutch e of the metal pin d forms one free end of the resistor n> already mentioned, which serves as a substitute or calming resistor. If one now applies a resistance W to be measured to the clamps of the instrument, the clamping nut is turned clockwise when it is tightened, the crutch e not making any metallic contact. If, on the other hand, you want to remove the measured resistance from the instrument again, the gill nut must be turned to the left. As a result, the crutch e attaches itself to the pin g and the switchover terminal is connected to the front terminal via the resistor w. The switching terminal prevents the ohmmeter from being switched off completely, thereby preventing the pointer from hitting it. In order not to have to observe any special regulations for switching off measured resistances, the instrument is given two switchover terminals (Fig. 3). This form described up to now is of course only an exemplary embodiment. One might as well reverse the whole arrangement. Then the contact is outside the terminal nut and inside the instrument housing. The contact spring m, which dragged on the lower end of the pin d in FIG. The task of the pin g in Fig. 1 has taken over the contact screw g in Fig. 4, as well as the screw i in Fig. 4 die. Hard rubber wall i of the chamber k in Fig. 1 represents. Finally, in place of the crutch e in FIG. 1 at the upper end of the pin d (FIG. 1), the crutch e at the lower end of the pin d in FIG. All the effective parts have only mixed up the place, with the advantage that the pin d does not need to be isolated from the clamping bolt. The only difference is that the pin in Fig. 1 is taken along by the terminal nut because it carries a crutch e at its upper end, which is located in a chamber k of the nut head, while the pin d in Fig. 4 only through the friction between the upper end of the pin, which can have a spherical or cylindrical shape here, and the springs m, m located in the nut head, is carried along. The field of application of the switchover terminal naturally also includes various other cases in addition to the one described. With the help of the clamp, a voltmeter can be set up for several measuring ranges or the sensitivity of a galvanometer can be changed, and finally a millivoltmeter can be graded in its sensitivity in the same way. "Godfather t-Än sprühhe: 1. Nut terminal with switching device, characterized in that by the normal use of the terminal any electrical lines can be switched. 2. clamping nut according to claim 1, characterized in that the threaded bolt, on which the nut runs, is pierced in its longitudinal axis, and that Through this hole a metal pin insulated goes into the interior of the nut, to be there with appropriate rotation of the same with its suitably shaped end and with the metal body of the nut in To make contact, with the gill nut and insulated pin with the poles of one Circuit are connected. 3. clamping nut according to claim 1 and 2, characterized in that the pin, which goes through the threaded bolt, does not require any isolation from this and with the (movable) terminal nut is connected by a friction clutch, so that the pen respectively. its appropriately shaped end with a corresponding rotation of the nut to an outside of the same lying metal body is guided and remains in contact with this body, without preventing the mother from continuing the movement she has begun. 1 sheet of drawings.