JPS6310361B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a dial gauge.

Conventionally, dial gauges have been widely used to magnify minute displacements of the probe at the tip of the spindle using a gear device, compare and measure the length of the object to be measured with a block gauge or a reference length, and read the dimensional difference. ing.

The general structure of a conventional dial gauge is:
As shown in Figure 2, the inner frame 1, back cover 2, and outer frame 3
A case body is constituted by the cover plate 4, and a spindle 5 is disposed on the case body so as to be displaceable in the axial direction.An intermediate pinion 7 is engaged with a rack 6 of the spindle 5, and the rotation of the intermediate pinion 7 is transmitted. Center pinion 9 via gear 8
, and the pointer 10 is rotated by a predetermined amount. Further, a backlash prevention gear 12 having a balance spring 11 is meshed with the center pinion 9, and a guide pin 13 is provided protruding from the spindle 5, and this guide pin 13 is connected to the guide groove 14A of the guide member 14. The spindle 5 is fitted into the shaft to prevent the spindle 5 from rotating. Further, as shown in FIG. 3, the intermediate pinion 7 and the backlash prevention gear 12 are connected to a main plate 15 and a first gear mounted on the main plate 15 via two supports 16 at a predetermined distance.
The center pinion 9 is rotatably assembled between the support plate 17 and the second support plate 15, which is attached to the main plate 15 in the same manner as the first support plate 17.
8 and the main plate 15, and the main plate 15 is attached to the inner frame 1 with the intermediate pinion 7, the backlash prevention gear 12, and the center pinion 9 incorporated. ing.

For conventional dial gauges like this,
After the intermediate pinion 7 and the like are assembled into the main plate 15, the main plate 15 is screwed to the inner frame 1 while adjusting the depth of engagement between the intermediate pinion 7 and the rack 6. The depth of engagement with the rack 6 tends to be uneven, which not only causes unstable measurement accuracy, but also tends to cause malfunctions due to fluctuations in the depth of engagement when subjected to impact, preventing smooth operation. There were times when I stopped doing it.

In addition, since the back cover 2 is screwed to the inner frame 1 at multiple locations, it is easy for the shape to change or misalignment at each attachment point during assembly or use.
This also led to instability in measurement accuracy.

Furthermore, in the case of a sealed dial gauge, a sealing mechanism must be provided for all of the engaging parts between the inner frame 1, back cover 2, outer frame 3, and cover plate 4. As a result, the structure tends to become complicated and assembly becomes difficult, resulting in a heavy economic burden.

An object of the present invention is to provide a dial gauge that has high stability in measurement accuracy, is easy to assemble, and can be easily sealed.

In the present invention, the case body is composed of two members, a container (corresponding to a conventional back cover and an inner frame) and a cover (corresponding to a conventional outer frame and cover plate), which are fitted together. In addition, it is possible to reduce the number of parts required for the sealing mechanism and to easily and perfect the sealing performance, and the spindle and the intermediate pinion meshed with the rack of the spindle are both held in the storage container. The object is to achieve the above object by increasing the stability of measurement accuracy and making assembly easy.

Embodiments of the present invention will be described below based on the drawings.

4 and 5 show an embodiment of a dial gauge according to the present invention. The case body 21 is composed of a cover 22 having a substantially inverted round tray shape, and a substantially round tray-shaped storage container 23 that is fitted into the cover 22 from the inner circumferential side of the cover 22.

The cover 22 is made of a transparent synthetic resin material, such as acrylic resin or polycarbonate resin, which has high transparency and excellent mechanical strength. Note that it is preferable that a rubber additive is added to the resin to improve impact resistance.

As shown in an enlarged view in FIG. 6, the inner circumferential surface of the cover 22 is provided with an inner circumferential groove 24 having a V-shaped cross section, while the outer circumferential surface of the container 23 is provided with an outer circumferential groove 24 having a rectangular cross section. A groove 25 is provided, and the cover 22 and the container 23 are arranged in an inner circumferential groove 24 and an outer circumferential groove 25.
They are fitted through a ring 26. O-ring 2
Reference numeral 6 is made of a flexible material such as hard rubber and has a round cross section, and is held by the outer circumferential groove 25 before the cover 22 and the container 23 are fitted together. An inclined portion 27 is formed along the circumferential direction on the middle lower end side, so that the cover 22 can be easily fitted through the O-ring 26. The cover 22 and the storage container 23 that are fitted together in this way are sealed by the O-ring 26, and complete waterproofness is achieved, but the cover 22 is not inserted into the storage container 23 while maintaining the sealed state. It is designed so that it can be rotated while having an appropriate frictional force against it. Further, on the inner peripheral side of the cover 22, a substantially ring-shaped long hand scale board 28 is fixed.

On the other hand, the storage container 23 is made of die-cast metal such as zinc, mold-formed hard plastic, or ceramic.
A spindle 31 is fitted at approximately the center position of 3 so as to be movable in the axial direction. As shown in FIG. 4, one end of the spindle 31 is fitted and supported by a stem 32 that projects from the outer peripheral surface of the container 23, and a measuring element 33 is provided at one end. Further, a waterproof rubber 34 made of a bellows-shaped rubber tube that can be expanded and contracted is fitted between the measuring tip 33 and the end of the stem 32, thereby making the one end of the spindle 31 completely waterproof. .

The other end of the spindle 31 is supported by being fitted into a guide tube 35 provided at a predetermined position on the outer circumferential surface of the storage container 23, and a set screw 36 is screwed into the other end of the spindle 31. 4 is restricted from moving more than a predetermined amount in the downward direction in FIG. There is.

As shown in FIG. 7, one end side of a coil spring 38 is fixed to a predetermined position of the spindle 31 in the storage container 23, and the other end side of this coil spring 38 is fixed to a predetermined position in the storage container 23. fixed,
As a result, the spindle 31 is urged downward in the figure. Further, a rack 39 is carved in a predetermined range along the longitudinal direction on one side of the spindle 31, and an intermediate pinion 40 is meshed with this rack 39. On the 36 side, a recess 41 is provided which is as deep as or slightly deeper than the bottom of the tooth of the rack 39.
When the intermediate pinion 40 is positioned within the recess 41, the intermediate pinion 40 and the spindle 31 are disengaged.

As shown in FIG. 5, a guide pin 42 is provided at approximately the center of the spindle 31 so as to protrude toward the bottom side of the storage container 23. It is slidably fitted into a guide groove 43 provided along the direction, and these guide pins 42 and guide grooves 43 constitute a rotation prevention mechanism 70 for the spindle 31 .

Further, one end side of the intermediate pinion shaft 40A of the intermediate pinion shaft 40 is supported by a first boss 44 formed by raising the bottom surface of the storage container 23, and the other end side is supported by a base plate 45. There is. Main plate 4
5 is an inner peripheral shelf 4 formed on the inner peripheral side of the storage container 23.
6 and is supported at a predetermined height within the container 23 and fixed with screws 47. Main plate 45
A short hand 51 is fixed to the tip of the intermediate pinion shaft 40A, which is supported by the first boss 44 to maintain a proper meshing state between the pinion 40 and the rack 39. An enlarged gear 52 is fixed adjacent to the intermediate pinion shaft 40 .

A center pinion 53 is meshed with the enlarged gear 52, and a center pinion shaft 53A to which the center pinion 53 is fitted and fixed is connected to the base plate 45 and the support plate 5.
4 at the center of the container 23, and this support plate 54 is fixed by screws 56 to a second boss 55 formed by protruding the bottom surface of the container 23 to a predetermined height. In addition, the center pinion shaft 53A
A long hand 57 is fixed to the tip.

As shown in FIG. 4, the center pinion 53 is meshed with a backlash prevention gear 61, and the rotation shaft 6 of the backlash prevention gear 61 is engaged with the center pinion 53.
1A is supported by a third boss (not shown) provided on the bottom surface of the container 23 and the base plate 45. Further, the center end of a hairspring 62 for prevention of backlash is fixed to the rotating shaft 61A.

The other end of the hairspring 62 is located at one of two notches 63 and 64 provided close to each other on the upper edge of the storage container 23, as shown in an enlarged view in FIG. 63, the balance spring 62 is inserted into the notch 63 by expanding the other notch 64 toward the one notch 63.
is clamped and fixed to the storage container 23. On this occasion,
Notch 64 into which hairspring 62 is not inserted
Alternatively, a means for press-fitting a press-fitting pin 65 having a diameter slightly larger than the width of this notch 64 may be used.

The reference numeral 66 in FIG. 5 is a disk-shaped center disk, and the intermediate pinion shaft 4 is attached to this center disk 66.
Insertion holes are provided through which the 0A and center pinion shafts 53A are inserted, and a scale for the hour hand is provided.

The procedure for assembling this embodiment is as follows: First, the spindle 31 is inserted and held in the storage container 23, and the guide pin 42 is inserted into the guide groove 43. Next, the intermediate pinion shaft 40A is held by the first boss 44 on the bottom of the storage container 23, but at this time, the seventh
As shown in the figure, the recess 41 of the spindle 31
If the spindle 31 is moved along the axial direction so that the intermediate pinion 40 is located inside, the intermediate pinion 40 and the spindle 31 can be kept in a disengaged state.
Incorporation is extremely easy. Also, the third
A rotating shaft 61A is incorporated into the boss (not shown),
A support plate 54 is attached to the second boss 56, and a center pinion shaft 53A is installed in this support plate 54.
After that, the base plate 45 is attached to the inner peripheral shelf 46.

The hairspring 62 attached to the rotating shaft 61A is wound up while the intermediate pinion 40 and the spindle 31 are in a disengaged state.
This is done by rotating the spindle 31, and then a set screw 36 is attached to one end of the spindle 31.

After each necessary part is assembled into the container 23, the cover 22 is press-fitted into the container 23, and the assembly is completed.

This embodiment has the following effects.

Since both the spindle 31 and the intermediate pinion 40 are directly held in the housing 23, the depth of engagement between the rack 39 and the intermediate pinion 40 does not change.
The reliability of measurement accuracy is improved, and the operating condition can be made good, and there is no risk of malfunction or inoperability even if subjected to impact.
Moreover, since the intermediate pinion 40 can be assembled after the intermediate pinion 40 and the spindle 31 (rack 39) are once disengaged (see FIG. 7), the assembly work is extremely easy.

Furthermore, since the spindle 31 is provided with a spindle rotation prevention mechanism 70, the tooth tip surface of the rack 39 will not be tilted, and what is equivalent to the conventional back cover and inner frame can be replaced with one. Since it is integrally formed with the housing 23, there is no risk of the shape changing, and from these points as well, changes in the depth of engagement between the intermediate pinion shaft 40 and the rack 39 are prevented.

In addition, conventionally the movement was built into the main plate and was attached to the inner frame, which required a large number of parts.
Assembly was also complicated, but in this embodiment, many parts are directly assembled into the storage container 23, so misalignment between each part is less likely to occur, and the number of parts itself is reduced, making assembly easier. , economical efficiency is also improved.

In addition, the case body 21 includes a cover 22 and a storage container 2.
Since the cover 22 and the container 23 are fitted together via the O-ring 26, not only dustproofness but also high waterproofness can be easily achieved.

In the above-described embodiment, the cover 22 is fitted to the container 23 via an O-ring, but in cases where the material of the cover 22 is relatively elastic, etc. As shown in FIG. 9, a protrusion 77 may be integrally formed on the inner peripheral edge of the cover 22, and the protrusion 77 may be directly inserted into the outer circumferential groove 25 of the storage container 23. Even in such a case, normal dustproofness is sufficiently achieved, but if necessary, a gasket 78 may be inserted between the lower edge of the cover 22 and the storage container 23, as shown by the dotted line in the figure. It may be interposed to provide complete waterproofness. In addition, the cover 22 is
It is not limited to the type that is press-fitted into 3, but may be screwed and fitted via a threaded portion.

Further, the waterproof cover 34 and the waterproof cap 37 are not necessarily necessary, and may be provided only when complete waterproofing is desired.

As described above, according to the present invention, it is possible to provide a dial gauge that has high stability in measurement accuracy, is easy to assemble, and is easy to make waterproof.

[Brief explanation of the drawing]

Fig. 1 is a rear view showing the internal structure of an example of a conventional dial gauge with the back cover removed, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is an assembly process of the conventional example. FIG. 4 is a front view showing the internal structure of an embodiment of the dial gauge according to the present invention with the cover removed, and FIG. 5 shows the internal structure of the embodiment with the cover attached. 6 is an enlarged sectional view of the fitting portion between the cover and the storage container in the embodiment, FIG. 7 is an enlarged front view of the spindle of the embodiment, and FIG. The enlarged perspective view shown in FIG. 9 is an enlarged sectional view of the fitting portion between the cover and the container in an embodiment other than the above. 21...Case body, 22...Cover, 23...Storage container, 24...Inner circumference groove, 25...Outer circumference groove, 26...O ring, 27...Slanted part, 31...Spindle, 33...Measuring point, 39...Rack, 40... intermediate pinion, 41
... recess, 42... guide pin, 43... guide groove, 51...
Short hand, 57... Long hand, 70... Spindle rotation prevention mechanism.

Claims (1)

[Scope of Claims] 1. A storage container having a substantially round tray shape with an integrated bottom and peripheral side portion, into which a cover equipped with a scale plate is fitted, and a container formed by protruding from the bottom of the storage container. The first
a boss, a second boss, and a third boss, each of which is fitted into the container so as to be able to be displaced in the axial direction, and has a measuring element at one end and a set screw that defines a displacement range at the other end. a spindle having a rack formed on its side surface; a recess formed in the spindle at an end of the rack on the set screw side; and biasing means for biasing the spindle in the axial direction of the gauge head. an intermediate pinion shaft having an intermediate pinion that engages with the rack and disengages with the spindle due to the recess, and one end of which is supported by the first boss; a center pinion shaft having a center pinion and a pointer to be transmitted, one end of which is supported by a support plate fixed to the second boss; and a backlash prevention gear meshing with the center pinion; a rotating shaft with one end supported by the third boss; one end fixed to the rotating shaft and the other end inserted into one of two adjacent notches formed in the storage container; a hairspring fixed at one notch by expanding the other; the intermediate pinion shaft; the center pinion shaft;
A dial gauge comprising: a base plate that supports the other end of each of the rotating shafts and is fixed to the storage container.