JPH0810133B2 - Position detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a position detector for detecting the position of an object surface placed in a three-dimensional space by a detection needle, and particularly to a position detector for a housing. The present invention relates to a position detector having a structure capable of easily and accurately setting a tip position.

In a position detector in which the surface of an object and the tip of a detection needle are brought into contact with each other to detect the position thereof, the relative positional accuracy between the housing supporting the detection needle and the tip of the detection needle directly affects the detection accuracy. Since it is impossible to obtain the relative positional accuracy between the tip of the detection needle and the housing depending on the processing accuracy, it is necessary to perform an operation of initially setting the tip of the detection needle to an accurate position after assembly.

-Prior Art- Fig. 4 is a cross-sectional view schematically showing the structure of a conventional position detector, 1 is a housing having an opening 8 on the bottom surface, 7 is a detection needle extending from the opening 8, and 12 is a detection needle. Base plate integrated with 7,
Reference numeral 13 denotes a spring that biases the base plate 12 toward the bottom plate 35 of the housing 1, and reference numeral 18 denotes a plurality of support pairs provided between the bottom plate 35 and the base plate 12. Generally, the support pair 18 is provided at each apex position of an equilateral triangle with the detection needle 7 as a center, and one support pair is provided with a screw 36 screwed to a bottom plate 35 substantially parallel to the detection needle 7 and a base plate facing the screw 36. It is composed of a seat 37 provided in 12 and a spring 13
The tip of the screw 36 and the catch 37 are pressed by the biasing force of the
Is held in a stable position. 38 is a lock nut for fixing the screw 36.

In such a conventional position detector, the screw of the supporting pair is
By moving the 36 back and forth, the housing 1 and the tip of the detection needle
Initial position setting with 30 is done. That is, the detection needle 7 is tilted by appropriately rotating and advancing and retreating the screw 36 so that the tip 30 thereof is aligned with the axis of the housing 1, and in that state, the lock nut 38 is fixed to each screw to detect the detection needle 7. The tip 30 is being initialized.

-Problems to be Solved by the Invention- However, in order to set the position of the detection needle tip 30 by the above means, very delicate and skilled work is required. because,
Since the lead of the screw 36 becomes very large with respect to the required positional accuracy of the detection needle tip 30, even if the screw 36 is slightly rotated, the detection needle tip 30 moves largely.
Therefore, in the actual work, it is necessary to repeat the operation of slightly applying a force in the rotation direction to the screw 36 and the operation of measuring the position of the detection needle tip 30, so that the lock nut 38 is fixed. Depending on the operation, the tip of the detection needle
This is because 30 is out of the required accuracy range, and the above operation must be performed while taking into account the deviation when fixed with the lock nut 38.

The lock nut 38 is provided on the screw 36 in order to increase the support rigidity of the screw 36 by generating a large internal stress in the screwing portion between the screw 36 and the housing 1 by fastening the lock nut 38. That is, the reproducibility of the stable position of the detection needle 7 is repeatedly reproduced by reducing the fluctuations of the force acting on the screw 36 and the screwing portion when the base plate 12 is in contact with the screw 36 and when the base plate 12 is separated. This is to increase the

The present invention has been made in view of the above problems, and an object thereof is to obtain a position detector that can set the initial position of the detection needle tip 30 by a simpler operation.

-Means for Solving Problems-Next, technical means adopted by the present invention for solving the above problems will be described with reference to the reference numerals attached to the accompanying drawings.

In the position detector of the present invention, the adjusting plate is provided in the housing 1.
15 is loosely fitted, and a support pair 18 for restricting the stable position of the detection needle 7 is interposed between the adjustment plate 15 and the base portion 12 of the detection needle, and the spring 13
The base 12 is biased toward the adjusting plate 15 to support the detection needle 7 at its stable position. The adjusting plate 15 is biased by the second springs 14 and 14a in the extending direction of the detection needle 7, at least a part of the peripheral surface thereof is tapered surfaces 23 and 23a, and the side having the smaller diameter is a spring. It is attached toward the biasing direction of 14 and 14a. The adjusting plate 15 has a structure that is screwed into the housing 1 and the tip thereof is fixed by the pressing force of the adjusting screw 21 that comes into contact with the tapered surfaces 23 and 23a of the adjusting plate. It is rational to provide three adjusting springs 21 at intervals of 120 degrees in the circumferential direction. One of them is used as a fixing screw 22 to fix one position on the peripheral surface of the adjusting plate 15. More preferably, the fixing screw 22 may be replaced with a pin or other protrusion that engages with the peripheral surface of the adjusting plate 15.

-Operation- In the position detector of the present invention, the adjusting screw 21 is rotated to press the adjusting plate 15 in the radial direction, thereby moving or elastically deforming the adjusting plate 15 to set the initial position of the detection needle tip 30. Is done. For example, when the adjusting screw 21 on the left side in FIGS. 1 and 2 is rotated to the right, a rightward pressing force acts on the adjusting plate 15 and the adjusting plate 15 is clamped and fixed between the facing screws 22 and 21. At the same time, since the adjusting screw 21 is pressed against the tapered surfaces 23 and 23a of the adjusting plate 15, the force for pushing down (FIG. 1) or pushing up (FIG. 3) the adjusting plate 15 is applied to the pressing portion of the adjusting screw 21. In addition, the detection needle 7 is tilted to move the tip 30 thereof. In addition, since the reaction force from the adjustment plate 15 acts on the screw surface of the adjusting screw 21, there is no risk of loosening without providing a lock nut, and the detection needle tip 30
Is caused by the pressing force applied from the adjusting screw 21 rather than the rotation angle of the adjusting screw 21, and therefore the amount of movement of the detecting needle tip 30 can be roughly grasped by the turning force applied to the adjusting screw 21. The position setting work is extremely easy and its accuracy can be improved.

Further, the adjusting plate 15 in the position detector of the present invention is held in a state where internal stress in the radial direction is generated by the pressing force of the plurality of adjusting screws 21 in the radial direction, and at the same time, the adjusting screw 21 that abuts the tapered surface 23. Axial component of pressing force and second spring
It is held in a state where internal stress is generated also in the axial direction by the urging force in the opposite direction acting from 14, 14a. Therefore, since the adjusting plate 15 is fixed to the predetermined position in the housing 1 with high rigidity, the change of the position and elastic strain of the adjusting plate 15 due to the contact and separation of the support pair 18 is small, and therefore the detecting needle 7 It also guarantees high repeatability with a stable position of.

-Embodiment- FIG. 1 is a view showing a first embodiment of the present invention, in which 1 is a housing of a detector, 2 is a shank which is substantially integrated with the housing 1, and 3 is electrical insulation internally fixed in the housing 1. A battery case made of a material, 4 a battery housed in the battery case 3, 5 a battery fixing lid that is screwed into the housing 1 and presses the battery 4, 6 is an LED for contact detection fixed to the housing 1, Reference numeral 7 is a detection needle that extends through an opening 8 in the center of the bottom plate of the housing 1, and 9 is a flexible dustproof cover that closes the gap between the housing 1 and the detection needle 7.

The detection needle 7 is fixed to the base plate 12 via an insulating sleeve 11, and is biased downward by a compression coil spring 13. A disc spring is placed between the base plate 12 and the bottom plate of the housing 1.
An adjusting plate 15 urged toward the base plate 12 at 14 is loosely fitted to the housing 1. On a surface of the base plate 12 and the adjusting plate 15 facing each other, a support pair 18 including a seat 16 and a sphere 17 is provided.
Are arranged at the respective vertex positions of an equilateral triangle with the detection needle 7 as the center, and the seat 16 and the sphere 17 are pressed against each other by the biasing force of the spring 13 to hold the detection needle 7 in its stable stationary position. . The seat 16 shown in the figure has three balls that make three-point contact with the sphere 17 fixed to the adjusting plate 15 in the recess provided in the base plate 12, and the other two seats not shown are However, since these structures and various other structures of the supporting pair are known, the description thereof will be omitted here. In the illustrated embodiment, in addition to these support pairs, a coil spring 19 erected on the adjusting plate 15 is fitted into the through hole 20 of the base plate 12, and the support pair 18
The rotation around the axis of the detection needle 7 when the is separated is loosely regulated to improve the restoration accuracy to the stable position.

On the body of the housing 1, the adjustment plate 1 is arranged at intervals of 120 degrees around the circumference.
Radial direction toward the peripheral surface of 5 (direction orthogonal to the detection needle 7)
2 screw holes and 1 through hole are provided, an adjusting screw 21 is screwed into the screw hole, and a fixing screw 22 is inserted into the through hole. A screw hole is provided at one position on the circumference of the adjusting plate 15, and the screw hole is screwed into the fixing screw 22. The tip of the adjusting screw 21 is hemispherical, and the peripheral surface of the adjusting plate 15 facing the tip of the adjusting screw 21 is a taper surface 23, and the tip of the adjusting screw 21 is pressed against the taper surface 23 to adjust the adjusting plate. 15 is sandwiched and fixed from three sides (see FIG. 2). The direction of the tapered surface 23 is the direction in which the biasing force from the disc spring 14 is locked by the contact between the tip of the screw 21 and the tapered surface 23, that is, the smaller diameter of the tapered surface 23 is the biasing force of the disc spring 14. It is a direction that matches the direction.

The detection needle 7 is connected to the LED 6 by the electric wire 25, and the other electrode of the LED 6 is connected to one electrode of the battery 4 via the electric wire 26 and the connection terminal 27 of the battery case. The other electrode of the battery 4 is connected to the housing 1 via the battery fixing lid 5,
Furthermore, the shank 2 and the machine tool body equipped with the shank 2 are connected to an object to be detected, and the LED 6 lights up when the detection needle 7 comes into contact with the object to be detected.

In the position detector with the above structure, two adjusting screws 21
Is rotated to fix the adjusting plate 15, and a local pressing force is applied to the adjusting plate 15 via the tapered surface 23 to adjust the adjusting plate 15.
The initial position of the detection needle tip 30 is set by inclining around the A and B lines in FIG. 2 connecting the tips of the screws 21 and 22.

FIG. 3 shows an essential part of the second embodiment of the present invention.
It is shown that a structure in which the adjusting plate 15 is biased by the compression coil spring 14a in the direction opposite to that shown in FIG. 1 is also possible. Further, in the structure shown in FIG. 3, the peripheral surface of the adjusting plate 15 is conical surface 23a. As such, a structure is adopted in which the adjusting plate 15 is fixed by pressing the conical surface 23a from three directions with three adjusting screws 21 without using fixing screws. Note that, as in FIG. 1, one of the screws 21 does not actually exist in the illustrated cross section. With this structure, the adjusting plate 15 is moved by retracting the three adjusting screws 21 equally.
Can be moved downward to adjust the vertical position of the detection needle tip 30. The position of the detection needle tip 30 is easier to set in the first embodiment in which one position of the adjusting plate 15 is fixed by the fixing screw 22 than in the second embodiment in which three adjusting screws 21 are provided.

-Effects of the Invention- For the reason explained in the above-mentioned action section, the position detector of the present invention makes it extremely easy to set the initial position of the tip of the detection needle after assembling, so that the initial position of the tip of the detection needle can be set easily. It is also possible to set more accurately. Further, according to the configuration of the present invention, it is not necessary to provide a screw or the like on the bottom surface of the housing, so that a space for mounting the dustproof cover at the tip of the housing is secured, the diameter of the housing can be reduced, and the detector can be made more compact.

Furthermore, since the adjustment plate that regulates the stable position of the detection needle is held at the set position under high support rigidity with internal stress remaining, the repeatability of the stable position of the detection needle is high, and therefore high-precision position detection is possible. Can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a plan view showing the fixing structure of the adjusting plate of FIG. 1, and FIG.
FIG. 4 is a cross-sectional view schematically showing a conventional structure, and FIG. 4 is a cross-sectional view of a main part showing an embodiment. In the figure, 1: Housing, 7: Detection needle 12: Base plate (base of detection needle) 13: Compression coil spring, 14: Disc spring 14a: Compression coil spring, 15: Adjustment plate 18: Support pair, 21: Adjustment screw 22: Fixing screw, 23: Tapered surface 23a: Conical surface, 30: Detection needle tip

Claims (1)

[Claims] 1. A position detector for measuring the position or surface shape of an object to be measured by bringing the tip of a detection needle (7) elastically supported at a stable position by a first spring (13) into contact with the object to be measured. In the above, the housing (1) for supporting the detection needle is internally provided with the adjusting plate (15), and the detection needle has the base (12) of the first spring through the plurality of support pairs (18). The adjusting plate is elastically supported by the adjusting plate, and the adjusting plate has a taper surface (23) on its peripheral surface, and a plurality of radial adjusting screws (21) screwed into the housing to press the taper surface. )
And the second springs (14) and (14a) for urging the adjusting plate in the direction in which the tapered surface has a smaller diameter, the adjusting plate is fixed at a fixed position in the housing, and position detection is performed. vessel.