JPS5920689Y2 - Clamp type measuring instrument - Google Patents

Description

[Detailed description of the invention] The present invention relates to a portable clamp-type measuring instrument, and is particularly suitable for work in narrow spaces by making the maximum width of the movable iron core the same as the maximum width when it is closed. This invention relates to a clamp-type measuring device with improved performance.

A clamp-type measuring device opens and closes a split core with a coil wrapped around it using a finger, inserts a current-carrying conductor into the core through the opening, and drives an indicator, etc. with the voltage generated at both ends of the coil. It is used to measure current, etc.

With conventional clamp-type measuring instruments, the maximum width of the split iron core when it is open is significantly larger than the maximum width when it is closed, so it can be used in places where wiring is crowded or where the distance between adjacent conductors is narrow, such as in a switchgear. The measurement work was extremely difficult.

That is, to explain the conventional example with reference to FIG. 1, at one end of the holder 2 of the clamp-type measuring instrument 1, there is an iron core consisting of a fixed iron core 3 curved or bent in an arc shape or an L-shape, and a movable iron core 4 having a similar shape. 5, and a meter 6 is attached to the other end.

The movable iron core 4 is integrated with a finger rest 7 for opening and closing the iron core, and by pushing the finger rest 7, the movable iron core 4 is opened using a shaft 8 as a fulcrum.

A core closing spring (not shown) acts on the finger rest 7 and urges the movable core 4 to close.

In such a conventional example, the outer end 4a of the movable core 4 is considerably separated from the line connecting the center of the shaft 8 of the movable core 4 and the center 5b of the contact surfaces 5a of both cores 3 and 4. Cage, width W1
is getting wider.

For this reason, when the movable core 4 is opened, the outer end 4a protrudes significantly from the side surface 2a of the holder 2, as shown by the two-dot chain line, and the core 5 when the movable core 4 is opened is larger than the maximum width W2 of the core 5 when the movable core 4 is closed. 5
The maximum width W3 of is significantly increased.

On the other hand, the effective opening width W when the core is opened is relatively narrow.

This is a drawback caused by the width W1 being increased because the movable core 4 is curved or bent.

The present invention was devised to eliminate the drawbacks of the prior art described above, and its purpose is to improve workability so that the maximum width of the core when the core is open is not much different from the maximum width when the core is closed. The object of the present invention is to provide an extremely good lamp-type measuring instrument.

In short, the present invention provides a clamp-type measuring instrument in which an iron core is attached to an end of a holder and a meter is attached to another part, in which a fixed iron core is extended almost linearly from one side of the holder end, and the fixed iron core is attached to the end of the holder. The movable core extends diagonally from the other side in a substantially straight line so that its tip is in close contact with the tip of the fixed core to form a magnetic path, and the maximum width of the core when the core is open is the same as when the core is closed. It is characterized in that it is configured to be approximately the same as the maximum width.

The present invention will be explained below based on embodiments shown in the drawings.

One end 12 of the holder 12 of the clamp-type measuring instrument 11
In a, there is an iron core 15 consisting of a fixed iron core 13 and a movable iron core 14.
However, a meter 16 is attached to the other end 12b.

The fixed core 13 is fixed to one side of the end portion 12a, and is attached to the holder 1.
2, it extends almost linearly in the longitudinal direction.

On the other hand, the movable core 14 extends diagonally straight from the other side of the end portion 12a, and its tip 14a is connected to the fixed core 13.
A magnetic path is formed in close contact with the tip 13a of the core, and a finger rest 17 extends from the opposite side, is pivotally supported by a shaft 18, and is always attached in the closing direction by a spring 19 for closing the iron core. Forced.

The shape of the movable core 14 is different from that of the conventional example, and is almost linear, so the line connecting the center of the shaft 18 and the center 15b of the contact surface 15a of both cores 13 and 14 and the movable core 14 The width W1 between the outer end 14b and the outer end 14b is much narrower than that of the conventional example.

Therefore, if the maximum opening position of the movable core 14 is parallel to the longitudinal direction of the holder 12, as shown by the imaginary line, the movable core 14
The maximum width W3 when the mouth is opened is approximately the same as the maximum width W2 when the mouth is closed.

On the contrary, the effective opening width W when the iron core 15 is opened is wider than that of the conventional example shown in FIG.

20 is a knob for switching the measurement range, 16 a is a meter 16
16b is a scale, and 16C is a pointer.

Note that the fixed core 13 may have a shape as shown in FIG.
The movable core 14 may have a shape as shown in FIG.

That is, a in FIGS. 3 and 4 is combined, which curves both iron cores 13' and 14' with a large radius of curvature, and the tip 1
3'a and 14'a are bent to form a contact surface.

In b of the same figure, both iron cores 13'' and 14'' are perfectly straight,
The tips 13''a and 14''a are simply cut diagonally to form contact surfaces.

Further, in C of the same figure, both iron cores 13" and 14"' are made completely straight, and the tips 13"a and 14"'a are bent to form a contact surface.

The present invention (first embodiment) is configured as described above,
The effect will be explained below.

When the finger rest 17 is pressed, the spring 19 is compressed and the movable core 14 opens to the position of the imaginary line, and the effective opening width W is
It is wider than the conventional example shown in FIG. 1, and the maximum width W3 of the iron core 15 is approximately the same as the maximum width W2 when the iron core 15 is closed.

Therefore, it becomes easy to hold the object to be measured in a narrow space or the like.

Further, the fixed iron core 13 extends substantially linearly in the longitudinal direction of the holder 12 from one side of the end 12a of the holder 12, and when the movable iron core 14 is opened, the movable iron core is also parallel to the longitudinal direction of the holder 12. Therefore, since the openings are distributed from the center line of the holder 12 and formed parallel to each other, it is easy to insert the object to be measured.

What is shown in FIG. 5 is a second embodiment of the present invention, in which the finger rest 27 is provided on the opposite side of the holder 22.

The finger rest 27 is pivotally supported by a shaft 28, a link 30 is connected to the finger rest, the link is connected to a crank 31 pivotally connected to the holding body 22, and a link 32 is connected to one end of the crank. , the link is the arm 24 a of the movable core 24
The rotation of the finger rest 27 is amplified by the link mechanism 33 and transmitted to the movable iron core 24.

The other components, ie, the fixed core 23, the spring 29, the measurement range switching knob 30, and the meter 26, are the same as in the first embodiment.

In this embodiment, by pressing the finger rest 27, the spring 29 is compressed and the link 30 is moved to the crank 31.
is rotated counterclockwise in FIG. 5, thereby moving the link 32 to the left and rotating the arm 24a and the movable iron core 24 clockwise to open as shown by the imaginary line.

When the finger rest 27 is released, the movable core 24 opens due to the restoring action of the spring 29 in the opposite direction.

Other points are the same as those in the first embodiment, so explanations will be omitted.

Since the present invention is constructed and operates as described above, it has the effect of allowing the object to be measured to be inserted into the iron core much more easily than the conventional example, even in a narrow space with crowded wiring. It will be done.

In addition, the effective opening width when opening the core is wider than the conventional example,
Moreover, since the opening is located in the center of the holder, there is no need to twist the measuring instrument against the conductor while inserting it, just move it straight, and in this respect too, work efficiency is dramatically improved compared to conventional methods. The effect of improving this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a front view of a conventional clamp-type measuring device, FIGS. 2 to 5 are related to an embodiment of the present invention, FIG. The figure is a partial front view showing a modification of the fixed core, FIG. 4 is a partial front view showing a modification of the movable core, and FIG. 5 is a partially cutaway front view of the measuring device of the second embodiment. 11 is a clamp type measuring device, 12 is a holding body, 12 a is an end of the holding body, 13 is a fixed core, 14 is a movable core, 15 is a core, 16 is a meter, W2 is the maximum width of the core when the core is closed, W3 is the maximum width of the core when it is opened.

Claims (1)

[Scope of utility model registration request] In a clamp-type measuring instrument in which an iron core is attached to an end of a holder and a meter is attached to another part, a fixed iron core extends in a straight line from one side of the holder end, and a fixed iron core extends in a straight line from one side of the holder end, and The movable core extends obliquely in a substantially straight line so that a magnetic path is formed with its tip in close contact with the tip of the fixed core, and the maximum width of the core when the core is open is the same as the maximum width when the core is closed. A clamp-type measuring instrument characterized in that it is configured to be of the same degree.