WO2000011429A1

WO2000011429A1 - Capacitive caliper

Info

Publication number: WO2000011429A1
Application number: PCT/CN1999/000121
Authority: WO
Inventors: Qiliang Chen; Shaoguang Chen; Haiping Liu
Original assignee: Qiliang Chen; Shaoguang Chen; Haiping Liu
Priority date: 1998-08-20
Filing date: 1999-08-19
Publication date: 2000-03-02
Also published as: CN2343572Y

Abstract

A capacitive caliper comprises a capacitive position sensor holding in the reverse side of the caliper. The main electrodes are embedded in the groove of the reverse side of the main beam, and the measuring electrodes are embedded in bottom plate of the slider. This construction of the main beam can protect against the ingress of oil, water and other contaminants. Particularly, it cannot occur that the measuring value fluctuates when the caliper is operated.

Description

Capacity grid type caliper technical field

The invention relates to a capacitive grid type digital caliper for measuring length, in particular to a capacitive grid type digital caliper with a sensor on the back of the main ruler. Background technique

The capacity grid digital calipers currently on the market, the fixed capacity grid electrode plate of the sensor is installed on the front of the main scale, and the digital capacity of the dynamic capacity grid electrode plate installed on the auxiliary scale is directly connected to the measuring circuit board. A measuring circuit is made on one side of the double-sided printed circuit board, and a moving capacity grid electrode is included on the other side. The moving capacity grid electrode includes a transmitting electrode group and a receiving electrode. The fixed capacity grid electrode is an induction electrode group. The moving capacity grid electrode faces the main ruler with a certain gap. The fixed-capacity grid electrode forms a pair of sensing capacitors. When the auxiliary ruler slides on the main ruler, the capacitance of the moving grid and the fixed gate changes. The change in this capacitance is measured to determine the position of the auxiliary ruler relative to the main ruler. This structure method is the simplest from the moving capacity grid electrode lead to the measurement display circuit. It is sufficient to drill the copper (hole metallization) on the double-sided printed circuit board. The advantage of integrating the moving capacity grid electrode and the measurement circuit is that the structure is simple, and the number of components to be installed is reduced, which is beneficial to reducing costs. The disadvantage is that when the components with different performance requirements are integrated, it is difficult to take into account their installation and alignment requirements and their respective support members. In particular, the installation of the moving capacity grid electrode requires accurate alignment and the support is not easily deformed, otherwise the measurement accuracy of the caliper will be affected, and the digital display component including only the measurement circuit and the LCD screen will have a strong effect on the support. There is no high requirement for installation and alignment. Usually, a plastic housing is used as a support for digital display components. This is suitable for measuring display circuits. However, the plastic housing is used as a moving capacity grid electrode. Its support is not rigid enough. The thermal expansion and contraction of the plastic case and the deformation of the force are relatively large. When measuring the handwheel, the force is too large. The deformation of the plastic case can cause the moving capacity grid electrode mounted on it to move relative to the main ruler. The displayed reading There will be errors. If you measure a certain size, 敫 The reading displayed by the caliper will change with the force state of the hand wheel, making people feel that the digital caliper is not as reliable as the mechanical caliper, because the reading of the mechanical vernier caliper does not change with the force state of the hand wheel. In addition, today's digital calipers have the problem that the fixed grid electrode of the sensor is mounted on the front side of the main ruler, which is vulnerable to contamination, because the caliper is always facing up when used and temporarily placed on the desktop, and oil, water and dust and other pollutants fall. There are more opportunities on the exposed electrodes. When there are pollutants between the electrodes of the sensor, the capacitance value will change and affect the accuracy of the caliper measurement. Summary of the invention

The purpose of the present invention is to overcome the disadvantages that the readings of the existing digital calipers change with the force state of the handwheel, and reduce the chance of the sensor being polluted by oil, water and dust.

The technical solution of the present invention is: A capacitive grid digital caliper provided by the present invention includes:

A ruler with inner and outer measuring jaws, including

A fixed grid electrode plate having grid-shaped sensing electrodes; and

A depth rod chute provided on the back of the main ruler; and

A sliding vice ruler with inner and outer measuring claws includes a slider having a bottom plate portion corresponding to the width of the main ruler and an edge portion bulging from the bottom plate portion. The slider is provided with

A moving grid electrode plate including a grid-shaped transmitting electrode group and a receiving electrode; a measurement display circuit digital display component electrically connected to the moving grid electrode plate, including a measuring circuit board and a digital display screen disposed on the front of the main ruler ; with

A depth rod that can slide along the depth rod chute,

It is characterized by,

The main ruler includes a groove suitable for the measuring range, and is arranged on the back of the main ruler, and is used for fixing the fixed grid electrode plate;

The bottom plate of the auxiliary ruler slider includes a groove, which is opposite to the groove of the main ruler and is used to fix the movable grid electrode plate; The side portion bulging from the bottom plate portion further includes a groove for placing the digital display component and the moving grid electrode plate as an electrical connection member.

According to the capacitive grid type digital caliper according to the present invention, the measurement circuit board fixedly connected to the bottom plate is disposed on the front surface of the main ruler, and the measurement circuit board and the measurement circuit board are located in the groove of the beveled portion. Electrical connection parts of the moving grid electrode plate on the back of the main ruler;

Wherein, the measurement circuit and the moving grid electrode are disposed on the same printed circuit board, and are disposed together in a groove of a bottom plate portion of the slider located on the back of the main ruler, and the groove of the side portion is used. Setting the measuring circuit board to be electrically connected with a digital display screen located on the front of the main ruler;

The back of the main ruler further includes a groove with a shallow depth, which is connected in parallel with the groove for setting the fixed grid electrode plate;

Wherein, a plate corresponding to the measuring range is also provided on the bottom plate portion of the auxiliary ruler, for covering the fixed grid electrode plate when the auxiliary ruler slides along the main ruler;

Wherein the depth rod is fixed on the plate;

The recess for placing the depth rod further includes a recessed recess for fixing the fixed grid electrode plate;

The depth rod is a plate corresponding to a groove on the back of the main ruler, and is configured to cover the fixed grid electrode plate when the auxiliary ruler slides along the main ruler.

The technical solution of the present invention is specifically: a groove is processed on the side of the bottom plate of the auxiliary ruler facing the main ruler, a movable grid electrode is inserted into the groove, and a fixed grid electrode plate is installed on the front side with a digital display screen. In the slot on the back of the main ruler of the caliper, the moving and fixed grid electrode faces on the back of the main ruler form a capacitive grid sensor. One way is to install the measurement circuit and the LCD screen on the front side of the main ruler together. On the auxiliary ruler, the moving grid electrode and the measuring circuit are respectively located on the back and front of the main ruler. The electrical connection between the measuring circuit and the moving grid electrode is passed through the auxiliary ruler on the side of the main ruler through a distance of the thickness of the main ruler. One method is to install the liquid crystal display only on the sub ruler located on the front side of the main ruler, and the measuring circuit and the moving grid electrode are embedded in a groove in the bottom plate of the sub ruler slider on the back side of the main ruler. The measurement circuit and the moving grid electrode can be combined on the same printed circuit board, and the measurement circuit and the display can be used together. The electrical connection is passed through the sub ruler on the side of the main ruler. This method can reduce the thickness of the sub ruler. The depth rod that moves with the sub ruler can be arranged to slide in the groove on the back of the main ruler. Slide in the groove on the front of the ruler. The groove on the back can be the groove inserted into the fixed grid. At this time, the depth rod covers the fixed grid to become a protective plate of the fixed grid, which can reduce the chance of the fixed grid being contaminated by oil, water, and dust. Only part of the fixed grid was exposed between the two measuring edges. The groove on the back of the depth rod sliding can also be a groove inserted next to the groove of the fixed grid. At this time, the fixed grid may or may not be covered with the protective plate (film). When the protective plate is covered, This protection plate can be integrated with the depth bar next to it, or it can be an independent protection plate (membrane) installed directly on the slider of the auxiliary ruler. It can be placed in the slot on the back of the main ruler or in the slot on the front of the main ruler.

In the caliper caliper of the present invention, the moving grid electrode plate is embedded in the base plate of the metal auxiliary ruler. After the hand wheel of the auxiliary ruler is stressed, the elastic deformation of the metal base plate is much smaller than that of the plastic casing of the digital display component on the auxiliary ruler In order to overcome the disadvantage that the position of the moving grid electrode plate of the existing caliper changes with the deformation of the plastic housing of the digital display module, the measurement result no longer changes with the force state of the hand wheel, and the reliability of the digital caliper is improved. According to the present invention, the capacity grid sensor is moved from the front side to the back side of the main ruler to reduce the chance of the sensor falling on oil, water and dust, and the present invention can also reduce the thickness of the sub ruler. Brief description of the drawings

In order to further understand the features, structures, and advantages of the present invention, the following describes in detail with reference to the accompanying drawings through the embodiments:

FIG. 1 is a first embodiment of the present invention, showing that a measurement circuit board is mounted on the front of the main ruler;

2 is a second embodiment of the present invention, showing that the moving grid electrode and the measurement circuit board of the present invention are integrally disposed in a groove;

FIG. 3 is a third embodiment of the present invention, showing a fixed installation of a depth rod and a protective plate for covering a fixed grid electrode of the present invention; FIG. Fig. 4 is a fourth embodiment of the present invention, showing a depth rod for covering a fixed gate electrode. The best way to implement the invention

One embodiment of the present invention is shown in FIG. 1: The main ruler 10 has a scale ruler 1 1 on the front side, grooves 13 and 14 on the back side, a fixed grid electrode plate 12 inserted into the groove 13, and the fixed grid electrode faces outside the groove. The depth of the groove 13 is equal to the thickness of the fixed grid electrode plate plus the protective layer. The bottom plate of the metal slider 21 of the auxiliary ruler 20 has a groove 26, and the movable grid electrode plate 22 is inserted into the groove 26. The depth of the groove 26 is The thickness of the moving grid electrode plate 22 with the protective coating layer is the same. The moving grid electrode is also facing out of the groove, so that the moving grid electrode is opposite to the fixed grid electrode surface. The thickness of the gate electrode protection film. A depth rod 25 is fixed on the slider 21, and the groove 14 can accommodate the depth rod 25 to slide therein. A spring piece 28 is installed between the main ruler 10 and the slider 21, and the spring piece is adjusted to an appropriate pressure by a screw 29. The slider 21 of the auxiliary ruler can slide smoothly on the main ruler 10 without a gap; the measurement circuit 23 and the digital display module housing 24 with a liquid crystal display are installed on the slider 21, and the measurement circuit 23 and the moving grid electrode 22 are respectively located Above and below the main ruler 10, the electrical connection between the two is passed by the side notch 27 on the slider 21, and the stopper 15 is installed below the tail of the main ruler, except for blocking the slider 21 from sliding out of the ruler It also has the function of suspending the main ruler of the caliper from the placement surface to prevent the placement surface from contaminating the fixed grid electrode on the main ruler.

As shown in FIG. 2, the second embodiment of the present invention is different from the first embodiment in that the moving grid electrode 22 and the measurement circuit 23 are located on the same printed circuit board and are inserted into the groove 26 of the auxiliary ruler slider 21. The electrical connection between the measurement circuit on the back of the caliper and the digital display on the front of the caliper is passed through the side notch 27 on the slider 21.

As shown in FIG. 3, the third embodiment of the present invention is embedded in the fixed grid plate in the deep groove on the back of the main ruler, and the depth rod slide groove is shallow in the groove, so that the depth rod 25 covers the fixed grid plate 12 and becomes the fixed grid. Protection board.

The fourth embodiment of the present invention is shown in FIG. 4. The protective plate 30 of the fixed grid plate 12 and The depth rod 25 is connected as a whole. Industrial applicability

The capacitive grid type digital caliper proposed by the present invention is an improvement on the existing capacitive grid type digital caliper. The fixed grid electrode is embedded in the groove on the back of the main ruler, and the movable grid electrode is embedded in the bottom plate of the auxiliary ruler slider. This can prevent the measurement result from changing with the force of the handwheel, and the master ruler can block some oil, water and dust from falling into the sensor, reducing the chance of the sensor being polluted and making the measurement inaccurate.

Claims

Rights request

1. A capacitive digital caliper comprising:

A ruler with inner and outer measuring jaws, including

A fixed grid electrode plate having grid-shaped sensing electrodes; and

A depth rod chute provided on the back of the main ruler; and

A depth rod that can slide along the depth rod chute,

It is characterized by,

The bottom plate of the auxiliary ruler slider includes a groove, which is opposite to the groove of the main ruler and is used for fixing the movable grid electrode plate;

The side portion bulging from the bottom plate portion further includes a groove for placing the digital display module and the moving grid electrode plate electrically connecting member.

2. The capacitive grid digital caliper according to claim 1,

It is characterized in that the measurement circuit board fixedly connected to the bottom plate is disposed on the front surface of the main ruler, and the measurement circuit board is provided with a groove in the beveled portion to electrically connect the movable circuit electrode plate on the back of the main ruler. component.

3.4 The capacitive grid digital caliper according to claim 1,

It is characterized in that the measurement circuit and the moving grid electrode are provided on the same printed circuit board, and are also provided together in a groove of a bottom plate portion of the slider located on the back of the main ruler. The concave circuit sets the measuring circuit board and a digital display on the front of the main ruler. Display electrical connection parts.

4. The capacitive grid digital caliper according to any one of claims 1 to 3, wherein

The back of the main ruler further includes a groove with a shallow depth, which is connected in parallel with the groove for setting the grid electrode plate;

A plate corresponding to the measuring range is also provided on the bottom plate portion of the auxiliary ruler for covering the fixed grid electrode plate when the auxiliary ruler slides along the main ruler.

5. The capacitive grid digital caliper according to claim 4,

It is characterized in that the depth rod is fixed on the plate.

6.4 According to any one of claims 1 to 3, the capacity grid type digital caliper is characterized in that the groove for placing the depth rod further includes a sunken groove for fixing the groove. Fixed grid electrode plate.

7. ¾1 The capacitive grid type caliper according to claim 6,

It is characterized in that the depth rod is a plate corresponding to a groove on the back of the main ruler, and is configured to cover the fixed grid electrode plate when the auxiliary ruler slides along the main ruler.