Geometrical instruments – Distance measuring – Opposed contacts
Reexamination Certificate
2001-07-23
2003-04-29
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Distance measuring
Opposed contacts
C033S813000, C033S830000, C033S784000
Reexamination Certificate
active
06553685
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a measuring instrument for bringing a spindle into contact with a workpiece to measure the dimension of the workpiece based on the moving position of the spindle. More specifically, it relates to a measuring instrument having a body and a spindle provided to the body movable in the axial direction of the body, in which the spindle is brought into contact with the workpiece by moving the spindle in the axial direction to measure the dimension of the workpiece, the measuring instrument being capable of displaying measuring force.
2. Description of Related Art
A measuring instrument having a spindle movably provided to a body to be in contact with a workpiece for detecting a dimension of the workpiece such as, for instance, a micrometer, also has a ratchet mechanism for bringing the spindle into contact with the workpiece at a constant force as well as a thimble for advancing and retracting the spindle in the axial direction thereof.
During measurement, after placing the workpiece between the anvil and the spindle, the thimble is rotated to move the spindle toward the workpiece, thereby sandwiching the workpiece by the anvil and the spindle. Subsequently, when hand is released from the thimble and a knob of the ratchet mechanism is rotated, the ratchet mechanism is freely rotated when more than a predetermined force is applied to the spindle, so that the measurement can be conducted at a constant measuring force.
In such a measuring instrument having the spindle to be in contact with the workpiece to measure the dimension of the workpiece, since the abutting force when the spindle is in contact with the spindle, i.e. the measuring force, exerts large influence on the measurement results, appropriate measuring force in accordance with the material and configuration of the workpiece is strongly desired.
However, though the constant measuring force can be maintained during measurement by the conventional measuring instrument, it is practically difficult to change the measuring force in accordance with the material and configuration of the workpiece.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a measuring instrument capable of measuring a workpiece with the most suitable measuring force in accordance with the material and configuration of the workpiece.
In the present invention, a biaser and a biasing force indicator for checking the biasing force of the biaser are used to obtain the constant measuring force.
A measuring instrument according to the present invention includes: a body; a spindle provided to the body movably in an axial direction thereof, the spindle being moved in the axial direction to contact to a workpiece for measuring the dimension of the workpiece based on a moving position of the spindle; a sleeve provided to the body movable in the same direction as the moving direction of the spindle and stoppable at a desired position; a connector for connecting the sleeve and the spindle and allowing a relative movement of the sleeve and the spindle by a predetermined stroke in the moving direction; a biaser accommodated in the sleeve for biasing the spindle through the connector in a direction to abut to the workpiece; and a biasing force indicator for indicating a biasing force of the biaser.
According to the above-described measuring instrument, when the sleeve is moved in the axial direction of the spindle during measurement, the sleeve, the biaser, the connector and the spindle are moved in the same direction in a body. After the distal end of the spindle touches the workpiece, when the sleeve is further moved in the same direction, since the spindle cannot be moved, the biaser is gradually compressed. The force for the biaser to bias the spindle, in other words, the measuring force, is an addition of the force increasing in proportion to the compression to the preload, which is displayed on the biasing force indicator.
Accordingly, the measurement can be conducted under the most appropriate measuring force in accordance with material and configuration of the workpiece while checking the measuring force indicated by the biasing force indicator. In other words, when the material of the workpiece is soft, the workpiece can be measured with minute measuring force and a number of workpiece can be measured always under constant measuring force.
In the above, the sleeve may be manually moved, or may be driven by a release, lever, rack and pinion, motor, etc. However, the sleeve may preferably be driven by the below-described thimble.
The connector may have one end fixed to either one of the spindle and the sleeve and the other end being movably connected to the other one of the spindle and the sleeve by a predetermined stroke. Alternatively, both ends may be movably connected to the spindle and the sleeve by a predetermined stroke.
Any biaser capable of biasing the spindle in a direction to abut to the workpiece may be used. However, helical pressure spring may preferably be used.
In the present invention, a biasing force adjuster for adjusting the biasing force of the biaser may preferably be screwed to the sleeve.
According to the measuring instrument, when the screwing position of the biasing force adjuster screwed to the sleeve is changed, since the distance from the biasing force adjuster to the connector changes, the compression of the biaser accommodated therebetween changes. Accordingly, the preload can be changed with a simple arrangement.
In the present invention, the biasing force indicator may preferably include: a scale rod provided to the connector penetrating the biasing force adjuster; and a scale formed along a longitudinal direction of the scale rod at a predetermined interval.
According to the above measuring instrument, when the preload is changed by changing the screwing position of the biasing force adjuster relative to the sleeve, the distance from the connector to the biasing force adjuster (i.e. the compression of the biaser) changes. Then, since the projection of the scale rod from the biasing force adjuster changes, the compression of the biaser, i.e. the measuring force can be read by reading the scale formed on the scale rod. Accordingly, the preload can be adjusted while looking at the scale, or the measurement can be conducted under a desired measuring force.
In the present invention, the biasing force indicator may preferably include: a threaded shaft provided to the connector penetrating the biasing force adjuster and having an external thread on an outer circumference thereof; a nut screwed to the threaded shaft and provided to the sleeve rotatable and immovable in the axial direction; and an index fixed to the nut.
According to the above measuring instrument, after bringing the spindle into contact with the workpiece, when the sleeve is further rotated in the same direction, the connector and the sleeve (or the biasing force adjuster) are relatively displaced. Then, since the threaded shaft and the nut are relatively displaced in accordance with change in the compression of the biaser, the nut is rotated, i.e. the index is rotated. Accordingly, the compression of the biaser, i.e. the measuring force can be read by the rotary angle of the index, thereby conducting measurement under desired measuring force while observing the rotary angle of the index.
In the above, a graduation plate having an angle scale indicating a rotary angle of the index may be attached to the sleeve side for accurately reading the rotary angle of the index.
In the present invention, the biasing force indicator may preferably include: a detection switch for detecting that the spindle and the sleeve approach with each other by a predetermined distance; and a display for displaying an actuation of the detection switch.
According to the above measuring instrument, after the spindle is in contact with the workpiece during measurement, when the sleeve is further moved in the same direction, the spindle and the sleeve are relatively displaced. Then, the compre
Hayashida Shuuji
Kuji Yoshitaka
Nakadoi Tetsuya
Nishina Shingo
Saito Osamu
Guadalupe Yaritza
Gutierrez Diego
Mitutoyo Corporation
Oliff & Berridg,e PLC
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