JPS6212964Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a micrometer head that allows easy zero adjustment of the scale for each measurement.

In general, a projection inspection machine typically uses a micrometer head to quantitatively move the stage. The micrometer head used in such a projection inspection machine is of a screw feed type because it is necessary to press and move the stage.

In such a screw-feed type micrometer head, the relative positional relationship in the axial direction of the thimble and spindle is determined by the thread pitch of the feed screw formed therein, so the relative positional relationship between the scale of the thimble and the scale of the sleeve is will also be determined by the screw pitch mentioned above.

On the other hand, in a projection inspection system, any point on the object to be measured placed on the stage is set as a reference position, aligned with the crosshairs on the screen, and then the stage is moved to align another point with the crosshairs on the screen; the amount of movement of the stage is read from the micrometer head, thereby enabling the distance between two points on the object to be measured to be measured.

However, since the image projected onto the screen of a projection inspection machine is magnified several tens of times, it is necessary to accurately align the reference position with the crosshairs of the screen when placing the object to be measured on the stage. It was difficult.

As a result, it has conventionally been very difficult to align the reference position of the object to be measured with the crosshairs of the screen while the scale of the micrometer head having the above-mentioned scale is set to zero.

Therefore, there has been a desire for a device that can arbitrarily change the relative positional relationship between the position of the spindle and the scale of the thimble sleeve.

Conventionally, methods for changing the relative positional relationship include forcibly shifting the sleeve relative to the thimble in the circumferential direction, or by making the scale plate on the sleeve slidable and moving the scale plate. There are known methods of shifting.

However, the former requires labor and
Since it is difficult to shift the scale plate by a certain amount with high precision,
This was not desirable in terms of accuracy. On the other hand, in the case of the latter, both methods involved shifting the scale of the sleeve relative to the thimble;
Although it is possible to set the scale to a certain integer scale, it is not possible to set the scale to the zero scale.As a result, in order to determine the actual amount of movement of the spindle from the scale read,
Calculations had to be made from the readings before and after that, which was inconvenient and caused frequent mistakes.

The purpose of the present invention is to provide a micrometer head that solves the above-mentioned problems.The thimble is divided into two parts, a scale cylinder part and a base part, and these parts are connected through a shoe biased by a spring. In order to enable frictional engagement for relative rotation and to fix the scale cylinder part to the sleeve, a key groove is formed in the sleeve and extends in the axial direction of the sleeve, and a key groove that faces the key groove when the scale cylinder part is rotated. In addition, a locking mechanism is provided which has a pin held in the scale tube so as to be able to come out and go into the keyway when facing the keyway, and the base can be rotated with the scale tube fixed to the sleeve. This feature is characterized in that only the spindle linked to the section can be moved forward and backward in the axial direction of the spindle.

An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, a sleeve 1 is composed of an inner tube 2 and an outer tube 3, and one end of the outer tube 3 is integrally fixed to the outer peripheral surface of the inner tube 2. As shown in FIG. Reference numeral 4 denotes a spindle that passes through the inside of the inner cylinder 2. This spindle 4
The shaft portion 4a is slidably held within one end of the inner cylinder 2, and the male screw portion 4b of the spindle 4, which is integral with the shaft portion 4a, is screwed into the female thread 2a at the other end of the inner cylinder 2.

A thimble 5 is attached to the end of the male threaded portion 4b of the spindle 4. The thimble 5 includes a base portion 6 fixed to the spindle 4, and a scale cylinder portion 7 fitted to the outer periphery of the outer cylinder 3 so as to be rotatable and movable in the longitudinal direction. This base body part 6 is integrally provided with a cylinder part 6a that fits on the outer periphery of the scale cylinder part 7, and an inner flange part 7a is integrally formed at the end of the scale cylinder part 7 on the side of the base body part 6. A female screw tube 8 screwed into the male screw portion 4a is integrally attached to the inner peripheral surface of the inner flange portion 7a.

On the end surface of the inner flange portion 7a on the base portion 6 side,
The middle portion of the arc-shaped shoe 9 is pivotally attached via a pin 10 (FIG. 3). A tension coil spring 11 is interposed between one end of the shoe 9 and the inner flange 7a. As a result, the other end of the shoe 9 is spring-biased toward the inner peripheral surface of the cylindrical portion 6a of the base portion 6, and the friction member 12 attached to the other end of the shoe 9 It is pressed against the inner peripheral surface. As a result, the base portion 6 and the scale cylinder portion 7 are frictionally engaged with each other.

Between the base part 6 and the scale cylinder part 7, there is a scale cylinder part 7.
A locking device 13 is provided for regulating and releasing the relative rotation of the sleeve 1 and the outer cylinder 3. This locking device 13 includes a keyway 14 provided on the outer circumferential surface of the outer cylinder 3 and extending in the longitudinal direction (axial direction of the sleeve 1), a reverse step-shaped hole 7b formed in the scale cylinder part 7, and a hole 7b. a plate 15 fixed to the side end of the outer cylinder 3; a plate spring 16 having one end fixed to the plate 15; Outer cylinder 3 from hole 15a
A pin 17 that can be freely retracted from the side, a plate 15 and a scale tube 7
A gap 18 is formed between the slider 19 and a slider 19 whose both ends are held in the gap 18 and protrude outside the scale cylinder 7 from the hole 7b. This slider 19 is held in the gap 18 so as to be slidable in the longitudinal direction of the scale cylinder portion 7, and an inclined surface 19 is formed on the portion of the slider 19 facing the leaf spring 16.
a is formed. Then, with the tip of the pin 17 mentioned above facing the key groove 14, slide the slider 19 to move the pin 17 to the inclined surface 14.
The tip of the pin 17 can be inserted into the keyway 14 by pressing the pin 17 toward the outer cylinder 3 side with the pin 9a.

In FIG. 2, 20 is a thimble scale engraved on the circumferential surface of the scale cylinder portion 7. Although not shown in the drawings, a scale on the sleeve is provided on the circumferential surface of the outer cylinder 3. In the figure, 21 is an operation knob attached to the base portion 6.

Further, the tip of the pin 17 is set to face the keyway 14 when the scale 20 and the scale of the sleeve are aligned at the zero position.

Next, the operation and reference point adjustment operation of the micrometer head having such a configuration will be explained.

During normal measurement operations, move the slider 19 to the second position.
While holding it in the position shown in the figure, pull out the tip of the pin 17 from the keyway 14. When the thimble 6 is rotated in this state, the spindle 4 moves forward and backward in the axial direction within the inner cylinder 2, and at the same time, the scale cylinder part 7 rotates integrally with the base part 6 and the spindle 4 due to the action of the friction member 12. move in the direction of its axis.

On the other hand, when adjusting the base point of the spindle 4, first,
Rotate the thimble 5 to align the scale 20 and the sleeve scale to zero, and insert the tip of the pin 17 into the keyway 1.
4. In this state, slide the slider 19 to the left in FIG. into the keyway 14. With this, the scale cylinder part 7
is unable to rotate with respect to the outer cylinder 3, so in this state, the base part 6 cannot be rotated against the frictional force acting between the frictional engagement member 12 and the inner circumferential surface of the cylinder part 6a. By rotating the spindle 4, the spindle 4 is displaced in the axial direction within the inner cylinder 2 by the action of the male thread 4b and the female thread 2a.

Further, at this time, the scale cylinder part 7 does not displace in the axial direction due to the action of the male thread 4b and the female thread cylinder 8 and maintains its original state, so that the base part 6 is displaced relative to the scale cylinder part 7 in the axial direction.

In this manner, the base point of the spindle 4 is adjusted.

As explained above, the present invention has a structure in which the thimble is divided into two parts, a scale cylinder part and a base part, and these parts are frictionally engaged so that they can rotate relative to each other, and the scale cylinder part is provided so as to be fixable to the sleeve. Therefore, by rotating the base body with the scale tube fixed to the sleeve, only the spindle linked to the base body can be moved forward and backward in its axial direction.
In this case, the frictional force that connects the base and the scale tube to each other through the shoe can be adjusted and set to a sufficiently low level using the spring, making it easy to rotate the base relative to the scale tube with a light force. This makes it possible to easily adjust the base point of the spindle.

Additionally, even if the micrometer head is used many times and the frictional engagement part between the base and the scale barrel wears out to some extent, the spring that biases the shoe automatically absorbs the gap between the worn parts and aligns the head. Therefore, it can be used stably all the time without any problems during use, and product quality is improved. moreover,
With this invention, you can simply insert and remove the pin into the keyway.
The scale cylinder part can be easily and quickly switched between rotatable and non-rotatable relative to the sleeve, and the structure is simple.

[Brief explanation of the drawing]

FIG. 1 is a front view of a micrometer head showing an embodiment of the present invention. Figure 2 is the − of Figure 1.
Line sectional view. FIG. 3 is a sectional view taken along the line -- in FIG. 2. 1...sleeve, 4...spindle, 4b...
Male screw, 5... thimble, 6... base, 7...
Scale cylinder part, 7a...Inner flange part, 8...Female thread cylinder, 9...Show, 10...Pin, 11...Tension coil spring, 12...Friction member, 13...
...Lock device, 14... Keyway, 16... Leaf spring, 17... Pin, 19... Slider.

Claims (1)

[Scope of utility model registration request] In a screw-feed micrometer head, a spindle supported by a sleeve is moved in the axial direction by rotation of a thimble, and the amount of movement of the spindle is read from scales on the thimble and sleeve. and a scale cylinder part, the base part and the scale cylinder part are frictionally coupled so as to be relatively rotatable via a shoe biased by a spring, and a key groove extending in the axial direction provided in the sleeve and and a locking mechanism comprising a pin held in the scale barrel so as to face the keyway as the scale barrel rotates and to be retractable into the keyway when facing the keyway. A micrometer head featuring: