JPS6233526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contact type measuring instrument equipped with a contact type encoder.

[Prior Art] A device that detects the mechanical displacement of a measuring point as an electrical digital signal is well known, and is applied in various measurement fields as a length measuring device, a position detector, and the like.

This type of mechanical displacement detection device electrically detects the length of the object to be measured as a scale or other displacement amount, but this electrical detection means can be electromagnetic, electrostatic, or photoelectric. In particular, photoelectric conversion type displacement detection devices are widely used as micrometers, calipers, coordinate measuring instruments, etc. due to their advantages such as miniaturization and high-precision measurement. It has been widely put into practical use.

However, conventional devices of this type have the drawbacks of being relatively expensive and consuming a relatively large amount of current.

In particular, in recent years, small length measuring devices and other devices use batteries as the driving source of the device, and for this reason,
There is a demand for low current consumption and long life.

In other words, in a digital displacement detection device, the electrical processing is performed by a C-MOS circuit,
These electrical processing circuits have the advantage that the current consumption is extremely small, whereas in conventional photoelectric devices, for example, the light emitting device for photoelectric conversion, such as a light emitting diode, consumes a large amount of current. However, this has caused a problem in that the overall current consumption increases.

In contrast to the non-contact type encoders mentioned above, contact type encoders have been known that detect electrical digital signals from opening/closing operations by contacting contacts, and can electrically detect mechanical displacement with a simple structure. It has the advantage of being very accurate, and has been put to practical use in certain fields, but it has only been used as a positioning mechanism that does not require precision, or as a rotational position detection device for large drive mechanisms. Its use was not considered at all in length measuring instruments when small size and high precision were required.

In other words, this type of contact type has fundamental drawbacks such as low contact reliability, extremely unstable contact state, and extremely easy contact state change after long-term use. Therefore, it was considered impossible to use it in length measuring instruments where poor contact directly causes errors.

However, this device has an advantage in that it can convert mechanical displacement into electrical digital pulses only by applying voltage, and basically does not require current consumption. We focused on the application to small measuring instruments that can be driven by batteries with low current consumption by combining with recent voltage type elements such as C-MOS transistors.

Therefore, we decided to replace the measuring instrument with a contact type encoder and a C-
It consists of a counter circuit consisting of MOS transistors, ICs, etc. that counts the voltage pulses of the contact type encoder section, and a measured value display section consisting of an LCD (Liquid Crystal Display) and others that displays the count value of the counter circuit as a measured value. This is considered to be suitable.

By configuring the measuring device in this way, the measuring device can be made cheaper and consume less current.

[Problems to be Solved by the Invention] Problems with the Prior Art However, since voltage type devices such as C-MOS transistors and ICs are generally not suitable for high-speed operation, when the measuring instrument is configured as described above, When the measurement signal output from the contact encoder section becomes high frequency, that is, when the moving speed of the probe becomes high, it becomes impossible for the measuring instrument to follow this, and the measured value displayed on the measured value display section becomes Errors may occur.

Therefore, there is a problem in that a measuring instrument configured in this manner becomes extremely inconvenient in actual use.

Purpose of the Invention The present invention has been made in view of the problems of the prior art, and its purpose is to provide a contact type measuring device that does not cause errors in the displayed measuring device even when the movement measure of the measuring point becomes high. Our goal is to provide the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a scale contact group arranged in a predetermined direction, and contact and non-contact with the scale contact group as the gauge head moves. a brush contact that repeatedly moves relative to the scale contact group; a contact encoder section that outputs a pulse-like measurement signal according to the measured amount; a counter circuit that counts the number of pulses of the measurement signal; In a contact type measuring instrument having a measurement value display section that digitally displays the measured quantity based on the count value of a counter circuit, the scale contact group has a coarse scale contact group arranged at a predetermined interval, and an interval between the coarse scale contact group. A resistor having different resistance values is connected to the coarse scale contact group and the fine scale contact group, and the counter circuit performs rough measurement from the potential change of the measurement signal. A measurement signal separation circuit that separates and extracts the signal and the fine measurement signal, a coarse scale counter that counts the rough measurement signal obtained from the coarse scale contact, and a coarse measurement signal that counts the fine measurement signal obtained from the fine scale contact. and a fine scale counter for resetting the count value, and the measured value display section is characterized in that it displays the sum value of the count value of the coarse scale counter circuit and the count value of the fine scale counter circuit.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a configuration diagram of a contact type measuring instrument according to a first embodiment of the present invention.

As is clear from the figure, the apparatus according to the present embodiment generates a pulsed measurement signal 100 according to the measured amount.
Contact type encoder unit 10 that outputs measurement signal 1
Counter circuit 1 that counts the number of 00 pulses
2, and a measured value display section 14 that digitally displays the measured amount based on the count value of the counter circuit 12.

In the contact type encoder section 10, a group of scale contacts made of conductors formed on a fixed contact base 16 are arranged in alignment in the AB direction, and each scale contact is made of a conductor formed on the contact base 16 and arranged in the AB direction.
A common connection is made by a conductive plate 18 whose longitudinal direction is oriented in the direction.

The scale contact group includes strip-shaped coarse scale contacts 20-1, 20-2, 20-3, . . . arranged at predetermined intervals.
...and strip-shaped fine scale contacts 22-1, 22-2, 22-3 that divide the interval of the coarse scale contact group 20,
It is composed of... Rough scale contact 20-
1, 20-2, ......, and fine scale contact 22-
1, 22-2, . . . extend from the conductive plate 18 in a direction in which each longitudinal direction crosses the AB direction, that is, in the right direction in the figure.

The characteristic feature of the present invention is that the coarse scale contact group 2
0 and the fine scale contact group 22 are connected to the conductive plate 18 via resistance plates 34 and 36 having different resistance values, respectively.

Then, a coarse scale contact group 20 and a fine scale contact group 22
are arranged with their tips aligned, and in this example, 1
The brush contacts 24 can move in sliding contact with the tips of the coarse scale contact group 20 and the fine scale contact group 22.

Here, coarse scale contact group 20 and fine scale contact group 2
2 is connected to a battery 26 via a conductive plate 18.

Further, the brush contact 24 is connected to the counter circuit 12.
The measurement signal is supplied to a measurement signal separation circuit 38 provided inside. The measurement signal separation circuit 38 includes the measurement signal 10.
From a potential change of 0, the rough measurement signal 100a and the fine measurement signal 100b can be distinguished and output to the counters 30a and 30b.

Here, the coarse measurement signal 100a outputted from the measurement signal separation circuit 38 is supplied to the count input of the first counter 30a and the reset input of the second counter 30b, and one fine measurement signal 100b is supplied to the count input of the first counter 30a and the reset input of the second counter 30b.
is supplied to the count input of the second counter 30b.

Note that these counters 30a and 30b are C-
It consists of MOS transistors, ICs, etc.

Count value 102 of each counter 30a, 30b
a, 102b is the count value 1 of the counter 30a
The signal is supplied to an upper digit display (LCD) 32a that displays 02a as the upper digit of the measured value, and a lower digit display (LCD) 32b that displays the count value 102b of the counter 32b as the lower digit of the measured value.

The contact type measuring device according to the first embodiment of the present invention is constructed as described above, and its operation will be explained next.

In the contact type encoder 10, the contact base 1
6 and the measuring head move relative to each other, the contact brush 24 slides on the scale contact group.

Here, the resistance value of the resistor 34 is set higher than the resistance value of the resistor 36, and when the probe moves, the measurement signal 100 shown in FIG. 2 is supplied to the measurement signal separation circuit 38. Measurement signal separation circuit 38
outputs a coarse scale signal 100a when the measurement signal 100 reaches V1 shown in FIG. 2, and outputs a fine scale signal 100b when it reaches V2, and as a result, the counter 3
A coarse scale signal 100a and a fine scale signal 100b as shown in FIG. 3 are supplied to 0a and 30b.

The rough measurement signal 100a and the fine measurement signal 100b are respectively input to counters 30a and 30b and counted, and at this time, the counter 30b is reset every time a pulse of the rough measurement signal 100a is generated.

The upper digit and lower digit numbers of the measured value are digitally displayed on the upper digit display 32a and the lower digit display 32b, respectively, and can be read by the operator.

By the way, when the measuring stylus moves quickly, the pulse interval of the re-measurement signal 100b becomes narrow, making it impossible for the counter 30b to count the fine measurement signal 100b.

However, even in this case, the pulse interval of the rough measurement signal 100a is not so narrow, and the counter 30
The counting operation by a continues, and only the high-order digit display 32a sequentially updates the high-order digits of the measured value.

Then, just before the movement of the measuring stylus stops, the moving speed of the measuring stylus decreases, allowing the counter 30b to count the fine measurement signal 100b,
When the movement of the probe stops, the lower digit display section 32b
The lower digits of the measured value are also displayed accurately.

As described above, according to the present embodiment, even when the moving speed of the probe increases, errors do not occur in the displayed measuring device.

Furthermore, in this embodiment, since only one brush contact 24 is required, there is an advantage that the contact type encoder section 10 can be manufactured easily.

FIG. 4 shows the main parts of a contact type measuring instrument according to a second embodiment of the present invention, and the same members as in FIG.

A feature of this embodiment is that the contact base 16 is formed into a cylindrical shape. This embodiment has the advantage that the contact base 16 can be formed in a small size, and that the scale contact group and the contact brush (not shown) can be brought into pressure contact with each other with a constant pressure.

Note that the coarse scale contact group 20 and the fine scale contact group 22 may be provided on the outer periphery of the contact base 16, and in this case, the contact base 16 may be a solid cylinder.

In addition, in the present invention, it is also preferable to provide a new contact brush at a position with the same phase as the contact brush 24, in addition to the contact brush 24 used in the above embodiment, in order to prevent pulses that cause errors in the measurement signal. .

It is also preferable to provide another new contact brush at a phase position different from that of the contact brush 24 in order to improve the accuracy of the measuring instrument and to determine the moving direction of the probe.

[Effects of the Invention] As described above, according to the contact type measuring device according to the present invention, it is possible to provide a contact type measuring device that does not cause measurement errors even when the probe moves quickly.

Moreover, since the number of contact brushes can be reduced to the minimum necessary, manufacturing is easy and
Costs can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a first preferred embodiment of the present invention, FIG. 2 is an explanatory diagram of the waveform of the measurement signal 100 of the first embodiment, and FIG. 3 is a rough measurement signal output from the measurement signal separation circuit. FIG. 4 is an explanatory diagram of the configuration of a contact type measuring device according to a second embodiment of the present invention. 10...Contact base, 12...Counter circuit,
14...Measurement value display section, 20...Rough scale contact group,
22...Fine scale contact group, 24...Brush contact, 3
0...Counter, 38...Measurement signal separation circuit.

Claims (1)

[Scope of Claims] 1. A group of scale contacts aligned in a predetermined direction, a brush contact that moves relative to the group of scale contacts while repeating contact and non-contact with the group of scale contacts as the probe moves; a contact encoder section that outputs a pulse-like measurement signal according to the measured quantity, a counter circuit that counts the number of pulses of the measured signal, and a measured value that digitally displays the measured quantity based on the count value of the counter circuit. In a contact-type measuring device having a display section, the scale contact group includes a coarse scale contact group arranged at predetermined intervals, and a fine scale contact group dividing the interval between the coarse scale contact groups at a predetermined pitch, Resistors having different resistance values are connected to the coarse scale contact group and the fine scale contact group, and the counter circuit is a measurement signal separation circuit that separates and extracts the coarse measurement signal and the fine measurement signal from the potential change of the measurement signal. , a coarse scale counter that counts the coarse measurement signal obtained from the coarse scale contact, and a fine scale counter that counts the fine measurement signal obtained from the fine scale contact and resets the count value with the rough measurement signal, A contact type measuring instrument characterized in that the value display section displays the sum value of the count value of the coarse scale counter circuit and the count value of the fine scale counter circuit.