JPH0337681B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a length measuring device, and more specifically, the present invention relates to an improvement in a length measuring device, and more specifically, the present invention relates to an improvement in a length measuring device, and more specifically, the value of a visually observed scale and the displayed value calculated and displayed by counting marks are calculated and displayed within the minimum distance between marks in the written scale value. The present invention relates to a length measuring device having a correction function to accommodate errors.

There is already a length measuring device that allows the measured length values to be confirmed both visually using a scale and using calculated values calculated by counting marks.

In this type of length measuring device, the process of printing a scale on a tape-shaped base material and the process of forming marks are performed in separate processes. Therefore, a relative error is likely to occur between the scale and the mark.

In conventional length measuring devices, this type of error causes a discrepancy between the visually observed scale value and the displayed value displayed after detecting the mark. For example, when the scale indicates 100cm, the displayed value is 101cm.

In view of this, the present invention has a correction function that has a correction function that allows the visually observed scale value and the displayed value calculated and displayed by counting the marks to fall within an error within the minimum distance between marks in the reference scale value. The purpose is to provide a length measuring device.

The length measuring device with correction function of the present invention is constructed as shown in FIG.

When the mark provided on the tape-like object a is detected by the detection means b, a pulse signal corresponding to the number of detected marks is emitted by the pulse signal generation means c, and the pulse signal is sent to the counting means d. It is counted by . On the other hand, the correction mark distance calculation means e
Then, the error equivalent amount between the display value displayed by the display means f when the tape-shaped object a is pulled out to a predetermined reference scale value and the reference scale value is inputted by the external input means g, The corrected inter-mark distance is calculated from the input error equivalent amount and the number of pulses counted by the counting means d, and the corrected inter-mark distance is displayed via the external output means h. be done.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to embodiments with reference to the drawings.

FIG. 2 shows an electronic tape measure 1 which is an embodiment of the length measuring device according to the present invention.

The electronic tape measure 1 is provided with a keyboard 4, a digital display 5, and a buzzer 6 on the front pulse 3 of the tape measure body 2, and a tape measure 7 is inserted from one side of the tape measure body 2 up to a certain scale value (for example, 5 m). It can be pulled out and stored in the tape measure body 2 freely.

The tape measure tape 7, which is a tape-like object, is formed from a tape-like base material, and has a scale 8 engraved within the tolerance defined by JIS in the length direction from the base end. Further, holes 9 having a diameter of about 1 mm are bored at regular intervals (eg, 2 mm pitch) along the longitudinal direction of the center of the tape measure tape 7.

In addition to the numeric keypad 4a that displays numerical information, the keyboard 4 includes, for example, an addition key 4b and an arithmetic key 4.
Various dedicated keys such as c and cm-scale conversion key 4d are provided.

The digital display 5 appropriately displays either the amount of the tape measure tape 7 to be pulled out or the numerical information from the keyboard 4, and the buzzer 6 indicates that the tape measure tape 7 is at a predetermined value inputted via the keyboard 4. This is to let you know when it has been pulled out.

The electronic tape measure 1 having such a configuration can perform four normal arithmetic operations using input from the keyboard 4. On the other hand, when the tape measure tape 7 is being drawn out, the input from the keyboard 4 is given priority. The amount by which the measuring tape 7 is pulled out is displayed.

Next, FIG. 3 illustrating the hardware of the length measuring device with correction function of the present invention will be described.

10 is a central processing unit (hereinafter referred to as CPU);
11 is an input side interface that intervenes to input various input signals to the CPU 10;
is an output side interface that sends output signals from the CPU 10 to various output devices. 13 is
RAM 14 is a ROM, and the contents of RAM 13 are powered by a backup power supply (not shown).
It is retained even when it is turned off.

A first projector 15 and a second projector 16 are provided at intervals equal to the pitch of the apertures 9 formed in the measuring tape 7, and the projectors 15, 16
is the first light receiver 1 provided below the measuring tape 7.
7 and a second light receiver 18.

When the light emitted from the projectors 15 and 16 passes through the aperture 9 and is received by the light receivers 17 and 18, the light receivers output two types of pulse signals S1 and S2 having phases different by 90 degrees. and is input to the counter 19 with direction determination. Counter with direction discrimination 19
Then, in response to the pulse signals S1 and S2, it is determined whether the tape measure tape 7 is moving in the pull-out direction or the storage direction, and a multiplied pulse signal S3 corresponding to the detected number of holes is generated. The multiplied pulse signal S3 is input to the input interface 11.

Note that the multiplied pulse signal S3 is read in priority over the input signal from the keyboard 4 by the interrupt signal S4 outputted by the counter 19 with direction discrimination.

The input side interface 11 receives the signal S
3. In addition to S4, a signal from a digital switch 20 for correcting the distance between marks stored in the RAM 13 is also input.

Next, among the software that regulates the operation of the hardware described above, the scale value and the display 5 are
The procedure for making corrections between the digital values displayed in and the digital values displayed will be explained with reference to the flowcharts in FIGS. 4A and 4B.

Now, put the measuring tape 7 on the reference scale value (for example, 5
m) and the value (α) corresponding to the difference between the uncorrected digital display and the standard scale value.
is set in the digital switch 20.

In the main program (FIG. 4A), the α value is read in a step, and the error amount (β) corresponding to that value is calculated in a step. On the other hand, in the interrupt program (FIG. 4B), pulse signals are read in steps, and the pulse signals are counted in steps. Then, in the step of the main program, the distance between the correction marks is calculated using the number of pulses counted by the interrupt program as the dividend and the number corresponding to the error amount (β) as the divisor, and the distance between correction marks is corrected in this way. Display the value in steps.

That is, to give an example using specific numbers, when the tape measure tape 7 is pulled out 5 meters (1 mm = 1 pulse), in this case, there is 5000 pulses and no error, but even if it is 5001 pulses, it will be displayed as 5000, 5001 pulses are displayed as 5000 pulses, and the difference between the scale and digital display is minimized.

In addition, in the above embodiment, the case where the reference scale value was set to one point was explained, but this is based on the assumption that the error between the scale value and the number of openings is in a simple linear relationship. If such an error cannot be estimated, a plurality of reference scale values may be set and the distance between correction marks between each reference scale value may be determined.

Further, in the above-described embodiment, the mark is an aperture 9 made in the measuring tape 7, but the mark is not limited to this, and may be a magnetic mark, for example, or a symbol such as a bar code. You can also do that. Depending on the type of mark, a magnetic head or the like may be used as the mark detection means.

As described above, the length measuring device of the present invention can keep the visually observed scale value and the displayed value calculated and displayed by counting the marks within an error within the minimum distance between marks at the reference scale value. The relative error between the scale and the mark, which occurs when the scale printing process for printing the scale and the mark forming process are performed in separate processes, can be absorbed to a minimum.

[Brief explanation of drawings]

Fig. 1 is a block diagram clearly showing the configuration of the length measuring device with correction function of the present invention, Fig. 2 A and B show an electronic tape measure of the embodiment, Fig. 2 A is a perspective view thereof, and Fig. 2 B
is an enlarged view showing the proximal end of the measuring tape,
FIG. 3 is a block diagram illustrating the hardware, and FIGS. 4A and 4B are flowcharts illustrating the software related to the correction function. a... Tape-shaped object, b... Detection means, c...
Pulse signal generation means, d... Counting means, e... Inter-correction mark distance calculation means, f... Display means, g...
... External input means, h ... External output means, 1 ... Electronic tape measure, 5 ... Digital display, 7 ... Tape measure tape, 8 ... Scale, 20 ... Digital switch.

Claims (1)

[Claims] 1. A tape-like object having scales and marks provided at intervals, a detection means for detecting the marks, a pulse signal generation means for generating a pulse signal corresponding to the number of detected marks, a pulse counting means for counting the pulse signals; a display means for displaying an equivalent amount of the tape-like object to be drawn out; and an indication by the display means when the tape-like object has been drawn out to a predetermined reference scale value. an external input means for externally inputting an error equivalent value between the displayed value and the reference scale value; and an inter-correction mark distance for calculating the distance between correction marks based on the output from the external input means and the output from the counting means. A length measuring device with a correction function, comprising: a distance calculation means; and an external output means for outputting the calculation result calculated by the correction mark distance calculation means to the display means.