JPH07103749A - Constant pressure type measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a constant pressure type measuring apparatus which can be made compact and increase a torque of a constant pressure device. CONSTITUTION:An engaging member 13 is set to a spindle 3. An inner sleeve 15 having a slit 15A formed to pass the engaging member 13 is fixed to a frame 4 of a main body. A spiral groove 16A to be meshed with the engaging member 13 is formed in an outer sleeve 16. A thimble 17 is fitted in an outer peripheral part of the outer sleeve 16 to be rotatable in a circumferential direction. A constant pressure device 25 including a leaf spring 18 is set between the outer peripheral part of the outer sleeve 16 and an inner peripheral part of the thimble 17. When not smaller than a predetermined force acts between the outer sleeve 16 and thimble 17, the device 25 idles the thimble 17 to the outer sleeve 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant pressure type measuring machine for measuring dimensions such as length and thickness of an object to be measured by the amount of movement of a spindle, and more particularly to improvement of a constant pressure device.

[0002]

2. Description of the Related Art Conventionally, a micrometer or the like has been known as a measuring machine for measuring the dimension of an object to be measured by the movement amount of a spindle. Various types of this micrometer have been developed, but the general structure is that the inner sleeve fixed to the body frame is machined with a female screw, and the male screw of the spindle is screwed into this female screw, and integrated with this spindle. Rotate the spindle with the thimble fixed to
The object to be measured is measured by reading this rotation amount. At the time of measurement, the object to be measured is pressed by the end of the spindle, but if the measurement pressure of this spindle is not constant, a measurement error will occur. Therefore, conventionally, there is a measuring machine provided with a constant pressure device for keeping the measured pressure constant. A conventional example of the constant pressure device is a ratchet mechanism attached to an end of a spindle. The ratchet mechanism includes a pair of ratchet wheels that mesh with each other and a compression coil spring that biases the ratchet wheels in a direction that meshes with each other. It is a structure in which the ratchet wheels are idled when a certain force or more is applied to the spindle.

[0003]

In the conventional constant pressure type measuring machine, since the constant pressure device is mounted in a state of protruding from the end of the spindle, a space is required for that amount and the measuring machine becomes large. There is. Also, to change the magnitude of the torque when the ratchet mechanism acts,
Although the spring force of the compression coil spring must be changed, there is a problem in that it is necessary to prepare a plurality of types of compression coil springs having different spring forces. Moreover,
Even if a compression coil spring having a strong spring force is used, there is a problem in that the magnitude of torque is limited.

An object of the present invention is to provide a constant pressure type measuring machine which can be downsized and which can increase the torque of the constant pressure device.

[0005]

Therefore, according to the present invention, the measuring device is incorporated between the inner peripheral portion of the thimble and the outer peripheral portion of the outer sleeve, and the spring force is higher than that of a conventional compression coil spring. It is intended to achieve the above object by using a leaf spring that is easy to adjust.

Specifically, the constant pressure type measuring machine of the present invention comprises a body frame, a spindle axially movable with respect to the body frame, a spindle provided at an end of the spindle and a radial direction of the spindle. A constant pressure type measuring machine that has an engaging member that protrudes in the direction of the axis and an engaging member drive mechanism that moves the engaging member forward and backward in the axial direction of the spindle, and that measures the dimension of the measured object by the movement amount of the spindle. The engaging member driving mechanism includes an inner sleeve formed with a slit through which the engaging member is inserted and extending in the axial direction of the spindle and fixed to the main body frame, and a circumferential direction on the outer circumference of the inner sleeve. An outer sleeve that is rotatably fitted and has a spiral groove formed in the inner peripheral portion that engages with the engaging member, and the outer periphery of the outer sleeve. The thimble is fitted to the outer sleeve so as to rotate freely in the circumferential direction and includes a leaf spring arranged between the inner peripheral portion of the thimble and the outer peripheral portion of the outer sleeve. And a constant pressure device for idling. here,
A ratchet wheel is formed on the inner peripheral portion of the thimble, the base end portion of the leaf spring is attached to the outer peripheral portion of the outer sleeve, the tip end portion of the leaf spring abuts the ratchet wheel, and a notch is formed on the outer peripheral portion of the outer sleeve. A portion may be formed, and the edge of the cutout portion may serve as a bending fulcrum with which an intermediate portion of the leaf spring abuts when the thimble idles with respect to the outer sleeve and the leaf spring bends.

[0007]

When the thimble is rotated, its rotational force is transmitted to the outer sleeve via the leaf spring and further to the engaging member provided on the spindle via the spiral groove of the outer sleeve. The rotation of the member is regulated by the slit of the inner sleeve, and the member can move only in the longitudinal direction of the slit. Therefore, the spindle moves only in the axial direction without rotating. Here, if the spindle contacts the object to be measured and the spindle continues to move in this state, the thimble tends to rotate with respect to the outer sleeve. When this rotational force exceeds a certain level, the thimble idles with respect to the outer sleeve, so that the spindle does not press the object to be measured any more. Further, since the spring force of the leaf spring can be easily adjusted by appropriately adjusting the width thereof, a leaf spring having a large width is used to increase the torque of the constant pressure device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of a constant pressure measuring machine according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof. In these figures, the constant pressure type measuring machine 1 has a waterproof / dustproof structure in which a spindle 3 can be retracted and retracted from a measuring machine main body 2 having an internal sealed structure. The measuring machine body 2 includes a U-shaped body frame 4, a spindle drive mechanism 5 for driving the spindle 3 forward and backward, a detector 6 for detecting a movement amount of the spindle 3, a U-shaped body frame 4 and a spindle 3. An interval regulating means 7 provided therebetween, a lid member 8 provided on the front surface of the U-shaped body frame 4, a digital display 9 provided on the front surface of the lid member 8 and a plurality of operation switches 10. ing.

The U-shaped main body frame 4 is provided with an anvil 11 at one end of the opening thereof, and the other end of the opening is axially movable with the spindle 3 whose one end surface is capable of contacting the anvil 11. Supported by. FIG. 3 shows the spindle drive mechanism 5 in an enlarged manner. The spindle drive mechanism 5 includes a pin-shaped engagement member 13 attached to the other end of the spindle 3 and an engagement member drive mechanism 14 that advances and retracts the engagement member 13 in the axial direction of the spindle 3. Has been done. The engagement member drive mechanism 14 is
An inner sleeve 15 having a slit 15A, through which the engaging member 13 is inserted, extending in the axial direction of the spindle 3 and having one end fixed to the U-shaped body frame 4.
An outer sleeve 16 in which a single spiral groove 16A is fitted on the outer periphery of the inner sleeve 15 so as to be rotatable in the circumferential direction and engages with the engaging member 13, and the outer sleeve 16 and the outer sleeve 16. Thimble 17 that is rotatably fitted to the outer peripheral surface of two, and two leaf springs 1 arranged between this thimble 17 and the outer sleeve 16.
When the thimble 17 is rotated in one direction, this rotational force advances the spindle 3 through the leaf spring 18, the spiral groove 16A of the outer sleeve 16 and the engaging member 13 and rotates in the other direction. And spindle 3
It is a structure that retreats. The spiral groove 16A is
The pitch is relatively large, specifically, larger than the screw pitch of the conventional micrometer.

The mounting structure of the leaf spring 18 is shown in FIGS.
Is shown in. 4 and 5, a recess 16D is formed on the outer peripheral portion of the outer rib 16 over the entire circumference thereof, and a base end of a leaf spring 18 is attached to the recess 16D with a screw 24. The ratchet wheel 1 in which the tip of the leaf spring 18 contacts the inner periphery of the thimble 17
7A is formed. The ratchet wheel 17A and the leaf spring 18 constitute a constant pressure device 25.
Has a structure in which the leaf spring 18 is bent when the thimble 17 rotates in the one direction and a certain force or more acts on the outer sleeve 16 so that the thimble 18 idles with respect to the outer sleeve 16. ing. The leaf spring 18 is formed with a plurality of cuts 18A from the vicinity of the base end portion to the tip end. This notch 18A
Is for facilitating the cutting of the leaf spring 18.
The spring force of the leaf spring 18 and thus the force for operating the constant pressure device 25 can be adjusted by appropriately setting the width dimension of the. 6, a notch 16B is formed in the recess 16D of the outer sleeve 16, and an edge 16C of the notch 16B is formed when the thimble 17 idles with respect to the outer sleeve 16 and the leaf spring 18 is bent. It is regarded as a folding fulcrum.

As shown in FIG. 2, between the spindle 3 and the U-shaped body frame 4 and the inner sleeve 1.
A seal member 26 is provided between each of the outer sleeve 5 and the outer sleeve 5. An end cap 27 is screwed into the opening end of the inner sleeve 15, and an opening 27A that communicates the inside and outside of the measuring machine body 2 is formed in the end cap 27. A porous member 28 that closes the opening 27A is attached to the inside of the end cap 27. The porous member 28 is a synthetic resin that allows gas permeation and liquid and solid permeation (trade name). GORE-TEX).

The detector 6 is provided with an index scale 29, which is a first detector provided inside the U-shaped body frame 4 via the interval regulating means 7, and the spindle 3
And a main scale 31 which is a second detection body provided via a scale mounting member 30. The main scale 31 has a structure including grid electrodes arranged at a constant pitch along the axial direction of the spindle 3 and earth electrodes arranged between the grid electrodes. The index scale 29 is
This is a structure including a transmission electrode and a reception electrode which are composed of a plurality of sets of transmission electrode elements. The measurement principle of this capacitance type encoder is as follows: Japanese Patent Publication No. Sho 64-11883 and Swedish Patent Application No. 77.
As described in detail in No. 14010-1, etc., it has a general structure. The detector 6 is connected to the digital display 9 shown in FIG. 1 via a counter and an electric component (not shown) such as a CPU. In the digital display 9, the spindle 3 is moved by operating the operation switch 10. The amount is displayed digitally.

The structure of the interval regulating means 7 is shown in FIGS.
In detail. In FIG. 7 and FIG. 8, the interval regulating means 7 includes a first mounting piece 32 to which the index scale 29 is adhered, a second mounting piece 33 to which the first mounting piece 32 is mounted with a screw 38, and a second mounting piece 33. 2 Mounting piece 33
Is attached with a screw 34A and a T-shaped plate member 35
The third mounting piece 36 is mounted on the mounting projection 4A of the U-shaped body frame 4 with a screw 34B. Three protrusions 37 are formed on the first mounting piece 32 at positions where they do not interfere with the index scale 29, and these protrusions 37 slidably contact at positions where their tips do not interfere with the electrodes of the main scale 31. The index scale 29 and the main scale 31 are relatively movable in the spindle axis direction.
In addition, it is held at a constant interval with a predetermined gap. Further, the hole 3 is formed in the center of the first mounting piece 32.
2A is formed, and the screw 38 is sandwiched across the hole 32A.
Two protrusions 32B for attaching the are formed.
In FIG. 9, the second mounting piece 33 is a leaf spring in which a notch is formed between both side portions 33A and a central portion 33B. Both side portions 33A are bent at their end portions to enhance rigidity. The central portion 33B has a tip portion 3
3C and the intermediate portion 33D are bent toward the first attachment piece 32 side, and the middle portion 33D is pushed toward the first attachment piece 32 side by the T-shaped plate member 35, so that the central portion 3
3B functions as a biasing means. The urging center of the central portion 33B is a position where the tip portion 35C abuts on the first mounting piece 32, and this position is the center of gravity of an imaginary triangle formed by connecting the three protrusions 37 (FIG. 2). reference).

The scale mounting member 30 and the spindle 3
The mounting structure for and is shown in FIG. In FIG. 10, the spindle 3 is a stepped columnar spindle body 3
A and an end member 3B screwed to a small diameter portion of the spindle body 3A and having the engaging member 13 attached thereto.
It consists of and. The main scale 31 is adhered to the scale mounting member 30, and holes 30A into which the small diameter portion of the spindle body 3A is inserted are formed at both ends of the scale mounting member 30. The scale mounting member 30 has a hollow portion 30B formed therein for reducing the weight, and an extra adhesive protruding from the scale mounting member 30 when the main scale 31 is bonded to the side portion thereof. Is formed with a concave portion 30C for storing the. In addition, in a measuring machine of a type that generates electric power by moving the spindle 3 back and forth, a rack is formed on the side of the scale mounting member 30, and a power generator having a pinion that meshes with the rack is arranged in the measuring machine body 2. The principle of power generation of a measuring instrument equipped with this power generator is a general structure, as described in detail in Japanese Patent Publication No. 4-31527 to Japanese Patent Publication No. 4-31529.

Next, the operation of this embodiment will be described.
With the object to be measured placed between the anvil 11 and one end of the spindle 3, the thimble 17 of the spindle drive mechanism 5 is placed.
Rotate in one direction. Then, this rotational force is transmitted to the constant pressure device 25, the spiral groove 16A of the outer sleeve 16 and the engaging member 13, but the engaging member 13 is rotationally restricted by the slit 15A of the inner sleeve 15,
Since the structure is such that it can move only in the slit longitudinal direction, the spindle 3 advances only in the axial direction without rotating. Since the spiral grooves 16A are formed at a relatively large pitch, the forward movement of the spindle 3 is faster than in the conventional case. As the spindle 3 advances, the pressure inside the measuring machine main body 2 decreases, but this decrease in pressure is absorbed by the gas passing from the outside of the measuring machine main body 2 through the porous member 28 to the inside. It Therefore, the spindle 3 moves forward smoothly.

The amount of movement of the spindle 3 from the anvil 11 is detected by a detector 6 having a main scale 31 and an index scale 29, and a digital display 9 is provided.
Display with. When one end of the spindle 3 comes into contact with the object to be measured, the amount of movement at that time is read. Here, when the spindle 3 moves, the positions of the main scale 31 and the index scale 29 are held at a constant interval by the interval regulating means 7.

When the thimble 17 is further rotated while one end of the spindle 3 is in contact with the object to be measured, the thimble 17 tends to rotate with respect to the outer sleeve 16. When this rotational force exceeds a certain level, the constant pressure device 25 operates and the thimble 17 idles. That is, the leaf spring 18 of the constant pressure device 25 is bent by the ratchet wheel 17A of the thimble 17 with the edge 16C of the outer sleeve 16 as a fulcrum, whereby the thimble 18 rotates with respect to the outer sleeve 16.

Therefore, according to the present embodiment, when the thimble 17 rotates and a certain amount of force acts on the outer sleeve 16, the leaf spring 18 is bent to move the thimble 18 to the outer sleeve 16. Since the constant pressure device 25 for idling is provided between the thimble 17 and the outer sleeve 16, the measured pressure of the spindle 3 can be kept constant. In other words, since the constant pressure device 25 of this embodiment is arranged between the thimble 17 and the outer sleeve 16, the size of the measuring machine can be reduced as compared with the conventional example in which the constant pressure device 25 projects from the end of the spindle. Even for the leaf spring 18 which itself has a weak spring force, the torque of the constant pressure device 25 can be increased by increasing the width thereof. Also,
Since the leaf spring 18 has a weak spring force, the constant pressure device 25 can be easily assembled. Furthermore, since the recess 16D is formed in the outer sleeve 16 for mounting the leaf spring 18, even if the leaf spring 18 is arranged, the inner peripheral diameter of the thimble 17 can be made close to the outer peripheral diameter of the outer sleeve 16,
From this point as well, the size of the measuring machine can be reduced.

In this embodiment, the base end of the leaf spring 18 is attached to the outer peripheral portion of the outer sleeve 16, and the tip of the leaf spring 18 is attached to the ratchet wheel 17A of the thimble 17.
To form a notch 16B on the outer peripheral portion of the outer sleeve 16, and the edge 16C of the notch 16B is
Since the thimble 17 idles with respect to the outer sleeve 16 and the leaf spring 18 bends, the middle portion of the leaf spring 18 comes into contact with the bending fulcrum, so that the fulcrum of the leaf spring 18 is close to the point of action. Also, the spring force of the leaf spring 18 can be increased to increase the torque of the constant pressure device 25. Further, since the plurality of notches 18A are formed from the vicinity of the base end portion of the leaf spring 18 to the tip thereof, the width dimension of the leaf spring 18 can be easily adjusted.

Further, in the present embodiment, the spindle drive mechanism 5 is constituted by including the outer sleeve 16 having the spiral groove 16A formed therein. Since the spiral groove 16A has a relatively large screw pitch, the spindle 3 is driven at high speed. Can be operated. Moreover, the movement amount of the spindle 5 is detected from the linear relative movement amount between the index scale 29 and the main scale 31, and the interval regulating means 7 is also provided.
By index scale 29 and main scale 31
Since and are held at constant intervals, the measurement accuracy is not reduced as compared with the conventional micrometer. In addition, the spindle 3, the U-shaped body frame 4, the thimble 17, and other essential structures for operating as a micrometer are maintained as before, so that an operator who is accustomed to using the micrometer can use the micrometer without feeling uncomfortable.

The opening 27A of the end cap 27 is provided with a porous member 28 which allows the permeation of gas but not the permeation of liquid and solid so that the internal pressure change of the measuring machine body 2 can be dealt with. The operation of the spindle 3 can be lightened without deteriorating the hermeticity of the machine.

In the above embodiment, the constant pressure device 25 has the leaf spring 18 and the ratchet wheel 17A formed on the inner peripheral portion of the thimble 17, but the structure of the constant pressure device is not limited to the above embodiment. Not something. For example, the ratchet wheel 17A may be omitted, and the tip end portion of the leaf spring 18 may abut on the cylindrical inner peripheral surface of the thimble 17. By selecting and using the thimble 17 in which the ratchet wheel 17A is formed and the thimble in which the ratchet wheel 17A is not formed, the magnitude of the torque of the constant pressure device can be changed. Further, a cutout portion 16B is formed on the outer peripheral portion of the outer sleeve 16, and the edge 1 of the cutout portion 16B is formed.
6C is a bending fulcrum with which the intermediate portion of the leaf spring 18 contacts when the thimble 17 idles with respect to the outer sleeve 16 and the leaf spring 18 is bent, but this edge 16C is not necessarily provided. Furthermore, the cut 18A of the leaf spring 18 and the recess 16D of the outer sleeve 16 do not necessarily have to be provided.

In the above embodiment, the number of spiral grooves 16A formed on the outer sleeve 16 is one, but the number may be plural. If there are a plurality of spiral grooves 16A and the same number of engaging members 13 are arranged at equal intervals, the load of one engaging member 13 can be reduced and the moment applied to the end 3B of the spindle 3 can be reduced. It can be eliminated and the durability of the measuring machine can be improved.

Further, the detector 6 is a capacitance type encoder having an index scale 29 as a first detection body and a main scale 31 as a second detection body,
In the present invention, a photoelectric encoder or a magnetic encoder can be used as a detector that detects the amount of movement of the spindle 3. Further, the measuring machine of the present invention may have an engaging member drive mechanism 14 for moving the engaging member 13 back and forth in the axial direction of the spindle 3, and the structure may measure the dimension of the object to be measured by the moving amount of the spindle 3. For example, a measuring machine that reads the moving amount of the spindle 3 on a scale may be used. Further, the measuring machine may be a dial gauge. In the present invention, it is not always necessary to provide the space regulation means 7 and the porous member 28. The spindle 3 does not necessarily include the spindle body 3A and the end member 3B.
It does not need to be configured separately.

[0025]

As described above, according to the present invention, the measuring device is incorporated between the inner peripheral portion of the thimble and the outer peripheral portion of the outer sleeve, and the leaf spring whose spring force is easily adjusted is used. There is an effect that the machine can be downsized and the torque of the constant pressure device can be increased. Furthermore, the base end portion of the leaf spring is attached to the outer peripheral portion of the outer sleeve,
Touch the tip of the leaf spring to the ratchet wheel of the thimble,
A notch is formed in the outer peripheral portion of the outer sleeve, and the edge of the notch is used as a bending fulcrum with which the leaf spring comes into contact when the thimble idles with respect to the outer sleeve and the leaf spring bends. The fulcrum of the spring is close to the point of action, and from this point as well, the spring force of the leaf spring can be increased and the torque of the constant pressure device can be increased.

[Brief description of drawings]

FIG. 1 is a front view of a constant pressure measuring machine according to an embodiment of the present invention.

FIG. 2 is a sectional view thereof.

FIG. 3 is an enlarged cross-sectional view showing an engagement member drive mechanism of a constant pressure type measuring machine.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is an exploded perspective view of the engagement member drive mechanism.

FIG. 6 is a cross-sectional view showing a mounting state of a thimble and an outer rib of the engagement member drive mechanism.

FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG.

FIG. 8 is an exploded perspective view showing a state in which the interval regulating means of the constant pressure measuring machine is attached.

FIG. 9 is an exploded perspective view of the interval regulating means.

FIG. 10 is an exploded perspective view of a spindle of a constant pressure measuring machine.

[Explanation of symbols]

 1 Constant Pressure Measuring Machine 3 Spindle 4 Body Frame 13 Engagement Member 14 Engagement Member Drive Mechanism 15 Inner Sleeve 15A Slit 16 Outer Sleeve 16A Spiral Groove 16B Notch 16C Edge 17 Thimble 17A Ratchet Wheel 18 Leaf Spring

Claims (2)

[Claims] 1. A main body frame, a spindle that is axially movable with respect to the main body frame, an engagement member that is provided at an end of the spindle and that projects in the radial direction of the spindle, and the engagement member. Is a constant pressure type measuring machine for measuring the dimension of the object to be measured by the amount of movement of the spindle, wherein the engaging member drive mechanism comprises: An inner sleeve having a slit through which the mating member is inserted extending in the axial direction of the spindle and fixed to the body frame;
An outer sleeve which is rotatably fitted on the outer circumference of the inner sleeve and has a spiral groove formed on the inner circumference to be engaged with the engaging member, and is rotatably provided on the outer circumference of the outer sleeve. A constant pressure device including a thimble to be fitted and a leaf spring arranged between the inner peripheral portion of the thimble and the outer peripheral portion of the outer sleeve, and idling the thimble with respect to the outer sleeve when a certain force or more is applied. A constant pressure type measuring machine characterized by having and. 2. The constant pressure measuring machine according to claim 1, wherein a ratchet wheel is formed on the inner peripheral portion of the thimble, and the base end portion of the leaf spring is attached to the outer peripheral portion of the outer sleeve, and , The tip of the notch is brought into contact with the ratchet wheel, and a notch is formed in the outer peripheral part of the outer sleeve, and the edge of the notch is a leaf spring bent by the idle rotation of the thimble with respect to the outer sleeve. A constant pressure type measuring machine characterized in that it is a bending fulcrum with which the intermediate portion of the leaf spring comes into contact.