SU50499A1 - Device for tensioning measuring tapes or wires (dynamostat) - Google Patents

Description

The still used tensioning devices for flexible measuring tapes or wires for accurate geodetic measurements are either very cumbersome and organizationally difficult to use, such as Carpentier machines with weights or Vitram machines with weights, or are very coarse devices that do not provide accurate metering of tension, such as spring dynamometers of various designs. On the other hand, the voltage of attention in combination with the proportionality of the muscular energy of the working spring dynamometer makes the workflow time-consuming, not excluding the possibility of a rough slip.

The proposed fixture (dynamostat) is intended to give the measuring tapes and wires a certain and constant tension during the production of readings on them with accurate geodesic linear measurements, for example, during basic and polygonometric works.

For this purpose, an unequal lever of the first kind, hinged on a pole-mounted coupling, is used in the device. A measuring tape or wire is attached to the short lever arm, and the long arm is equipped with a counterweight.

Depending on the tension of the measuring tape or wire, on the weight or on the ground, two forms of the device are proposed.

In FIG. 1 is a view of a tool for tensioning tapes or wires; FIG. in another form of implementation. . The device for tensioning a measuring tape or wire by weight (Fig. 1) is based on the principle of an unequal arm of the first kind. Shoulders /, 2 levers are located at an angle of 90 ° to each other. The lever is seated on a ball bearing 5, the axis 4 of which, by means of a special projection-bracket, is fixed on the coupling 6, movable along the pole 7. The height adjustment of the device is carried out by moving the coupling along the brush. A measuring chain or wire 8 is attached to a short shoulder / lever, and a counterweight 9 is mounted on a long shoulder 2.

Appropriate selection of arm lengths of the lever, and the counterweight 9 device can be calculated. for any constant tension used in the technique of accurate geodetic measurements, -10, 15, or 20 kg. The fixture shown in FIG. 1 is designed for a tension of 15 kg, which, when the lever arm ratio is 1: 3.5, makes it possible to have a counterweight 9 weighing 4.28 / g.

To hold the tape or wire from the opposite end of the fixture, a six-clip holder 10 with a comb P is intended to adjust the measuring tape or wire in height.

The embodiment of the device depicted in FIG. 2, based on the same principle of an unequal arm of the first kind, and is intended for the case of tensioning a measuring tape or wire over the ground. The shoulders /, 2 levers here are located in one line, being a continuation of one another. To transfer tension to the ground at the bottom of the crack, roller 12 is reinforced through which the bend is thrown 13. One end of the tie is attached to the short arm / lever, and a measuring tape or wire is attached to the other end of the pull during operation.

The device in comparison with the machines used for this is simple in design and portable, which is very important under the forwarding conditions of work.

Some rocking of the pole, and thereby balancing the lever, does not cause a change in the tension of the measuring instrument, since the counterbalance 9 is constant and the ratio of the lengths of the arms of the lever is constant.

Horizontal constituting force

// tension chain or wire will also be constant, which exactly agrees with the physical and mathematical positions of the chain line of the suspended flexible meter,

So far, no tensioning device with accurate geodetic measurements has met the condition of // constant. Therefore, all accurate geodesic measurements, now based solely on the theory of the catenary line. justify themselves only on lines close to the horizontal with small slopes. The fixture, as meeting the condition of a constant, permits the use of accurate measurements on lines with any slopes. The latter is very important in surveying.

The subject matter of the invention.

Claims (3)

1. Device for tensioning measuring tapes or wires (dynamostat), characterized by the use of an unequal arm of the first kind, which sits on an axis that is fixed to a mobile one. on the pole of the coupling, and to the short arm of which a measuring tape or wire is attached, and the long shoulder is provided with a counterweight. 2. The form of making the device according to claim 1, characterized in that, in the case of tension of the measuring tape or wire on weight, the arms of the lever are at an angle of 90 ° (Fig. 1). 3. The form of making the device according to claim 1, characterized in that, in the case of tension of the measuring tape or wire along the ground, the levers of the lever are located one on the continuation of the other and the short arm is connected to the measuring tape or wire by means of a flexible tie slung through the roller (Fig. 2). Fig FIG rv ten