JPS59182307A - Digital measuring tape - Google Patents

Abstract

PURPOSE:To prevent the influence of an error in work and abrasion due to aging change by calculating a coefficient of correction in the beginning of measurement and displaying a measured value on the basis of the coefficient of correction. CONSTITUTION:The output of a counter 18 is inputted to an arithmetic means 12 in the initial state wherein a battery is set through a correction coefficient calculating means 9 and a correction coefficient deciding means 10, and the current coefficient of correction is stored in a correction coefficient storage means 11. A direction deciding circuit 7 decides the rotational direction of the two- phase output of an encoder 5 firstly during measurement. Then, the counter counts up when the measuring tape 2 is in a draw-out direction or counts down when in a winding direction. The counted value is outputted to the arithmetic means 12.

Description

[Detailed Description of the Invention] 0) Industrial Application Field This invention converts the movement detection lid of a cave into an electrical signal, which is built into the case body and can be freely pulled out from the case opening, and used for length measurement. This invention relates to a digital tape measure that allows the results to be converted into any unit system and displayed digitally.

(B) Prior art In a conventional digital tape measure, a movable cave is pressed against the circumference of a measuring roller, a rotary encoder is connected to the rotating shaft of this measuring roller that rotates as the cave moves, and the output of this rotary encoder is was counted by a counter, the output of this counter was converted using an arbitrary unit coefficient, and the result of the calculation was displayed on a digital display.
In order to match the amount of movement of the vernier with the digitally displayed value, it was necessary to increase the dimensional accuracy of the thickness of the vernier and the circumference of the measuring roller as much as possible. However, there are limits to machining, and even if these errors are reduced, the longer the measurement distance, the more errors will accumulate in proportion to the measurement distance, and the vernier movement amount will not match the digital display value. . In addition, display errors become more pronounced due to wear and tear on the vernier and measuring roller due to long-term use.

(C) Purpose This F3A was developed to solve the problems of the conventional digital tape measure mentioned above.A correction coefficient is calculated at the beginning of measurement, and at the time of measurement, the measurement calculation value multiplied by this correction coefficient is calculated. To provide a digital tape measure capable of measuring and displaying with high accuracy without being affected by the effects of wear of a vernier, etc., due to processing errors or changes over time.

B) Structure The digital tape measure according to the present invention is built in the case body, and can be freely pulled out from the case opening. The rotation amount is converted by a roller, the rotation amount is fully encoded by a rotary encoder connected to the rotating shaft of this measuring roller, the output of this rotary encoder is counted by a counter, and the output of the counter is calculated by a calculation means. In a digital tape measure, the results can be stored in a storage means, and the output of these calculating means or storage means can be displayed on a display, and the preset count number set in advance at the beginning of measurement and the count counted by the counter. means for calculating a correction coefficient based on the number of outputs; determination means for determining whether the calculated correction coefficient is within an allowable range; and correction coefficient storage means for storing the correction coefficient determined and determined by the means. It is characterized by having the following.

(F) Embodiment A digital tape measure which is an embodiment of the present invention will be described below based on the drawings. FIG. 1 is an external view of a digital tape measure main body (1) that is an embodiment of the present invention, and FIG. 2 is a sectional view. In Fig. 2, a vernier measure (2) wound around a winding frame having a thin coiled spring (3) is attached to the center of the case, and its tip is connected to the vernier measure (2) through a measuring roller (4) in the middle.
2) Connected to the drawer opening. The measuring roller (4) has a vernier measure (2) along its circumference, and a pressure roller (6).
The measuring roller (4) is constantly pressed even when the tape is moving.
The mechanism is such that it moves while being pressed against it. The rotation of the measuring roller (4) results in the rotation of the rotary encoder (5) via a mechanically coupled shaft.

Figure 3 shows a functional block diagram for digitally displaying the encoder output.

First, the two-phase output of the encoder (5) is the direction discrimination circuit (7).
, the direction of rotation is determined. Furthermore, a counter (8) following the direction discrimination circuit (7) outputs a control signal that causes an addition (up) count if the vernier (2) is in the pull-out direction, and a subtraction (down) count if the vernier (2) is in the storage direction. The count output from the four-stage counter (8) is input to the calculation means (a) under normal usage conditions, but in the initial state when the battery is discharged, the output from the counter (first stage) is input to the correction coefficient calculation means (a). 9) and the correction coefficient determining means αO to the calculation means 4, and the correction coefficient at this time is stored in the correction coefficient storage means (11).Once the correction coefficient is stored, the above procedure is performed. This is the normal usage state. In the figure, the (a-8) side shows the state of the battery center, and the (bb) side shows the state after the correction coefficient has been stored. Calculating means (2)
Then, the count input from the counter (8) is multiplied by the value stored in the correction coefficient storage means (11), and the sum is displayed on the display α9.

The memory of the correction coefficient is not erased unless the battery is removed, so once it is used, it is a numerical value that can be used for a long time. Alternatively, if an error occurs between the tape draw-out length and the digital display during use, it goes without saying that the purpose is to remove the battery and correct it again. The case length addition means (141 is used during calculation to display the result of the calculation as a value that adds the length of the case body. Also, the storage means a3 temporarily stores and stores the displayed numerical value, and is used from now on. A storage memory is used that can be read and displayed from the storage means u4 at any necessary time and is stored even when the power is turned off.The above configuration is implemented by a microcomputer as shown in Figure 4 (CPU0 diagram). It is configured as a control device consisting of a beater and its peripheral circuits.

Next, the operation of the digital tape measure constructed as described above will be explained based on the flow chart shown in FIG. When you first install the batteries, all memories are cleared, and of course the correction coefficients are also cleared. In this state, the display α♂ shows a sign requesting correction (for example, from CAL to RAT
N:CLb) is displayed. Next, pull out the vernier measure (2) and draw it out to a predetermined position, e.g. 2.000mm.
2) Stop so that it cannot move. The number of input counts at this time is 2000 counts, which is an ideal value with no variation in the thickness of the measuring roller (4) and vernier (2).
If the measuring roller (4) diameter is finished small, fi 2
At tape draw of 000HM, a value greater than 2000 counts is entered. 2 if the roller diameter is large for correspondence
Even if 000ffi is pulled out, the number of roller rotations decreases and becomes smaller than the input count number I'12000 counts. A corrector -αΩ is used to correct this. Assuming that the roller diameter is large and 1992 counts are input, when the correction key αQ is operated, the set count number (currently 2000) and the input count number (1992) are calculated and a correction coefficient of 1.004016 is calculated. Calculated.

If the value of K is within the range of normal correction operations and within the error range that allows for the finishing of rollers, etc., R
The value of K falls within the range from the maximum value a' to the minimum value a set in 'OM' and is stored in the RAM. - (Figure 5 (CI))).

If the correction operation is not normal or if the vernier (2) is not moving in pressure contact with the measuring roller (4), the input count number will be too large or too small, and the value of K will also be smaller than a. Since the correction is no longer accurate as the correction becomes smaller than the value 1 or a, an error is displayed on the display unit α. In this case, the same operation may be repeated.

Next, when the value of K is memorized, from then on, the value obtained by multiplying the input count number by the correction coefficient of K is displayed (see Figure 5).
river)). The value of K is retained even when the power is turned off, and when the power is turned on again, it is determined that the correction coefficient has been stored, and the value of K is immediately multiplied and displayed without going through the correction coefficient calculation and judgment operation. The same applies below.

FIG. 6 is a diagram showing the state of use when performing inside measurement using the digital tape measure of this embodiment. Normally, the length measurement display value is expressed by the length of the vernier (2) protruding from the case exit, but when measuring the inside of a window frame (2υ etc.), the length of the vernier (2) is , and the length of the case body (1) is required.Therefore, an inside measurement key α force is provided.

The procedure up to multiplying the read value by the correction coefficient K is as described above. Thereafter, when the inside length measurement key α is pressed, the length of the case body (1) is added to the calculation result, and when the key is released, the normal length measurement display is restored.

In the above embodiment, the tape measure has the original measurement function, but the case body (1) is provided with a number key, and the calculation means 02 can calculate the input data from the number key and display the calculation result. In such a case, the measurement results of each part of the object to be measured can be stored and various calculations such as hypotenuse calculation can be performed with one key operation. It's very convenient.

(F) Effect The digital tape measure according to the present invention is configured as described above, and a correction coefficient for the measuring mechanism is calculated and stored before measurement, and a value multiplied by this correction coefficient is displayed at the time of measurement. The length of the vernier that was actually pulled out can be displayed correctly. Therefore, according to the present invention, there is no need to precisely process the vernier thickness and the circumference of the measuring roller, which reduces processing costs. This makes it possible to prevent display accuracy from deteriorating.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the appearance of a digital tape measure according to an embodiment of the present invention, and FIG. 2 is a sectional view. FIG. 3 is a functional block diagram showing the configuration of the embodiment. FIG. 4 is a configuration circuit diagram as an example. FIG. 5(1) (If) is a flowchart showing an example of a program for calculating a correction coefficient and displaying a measured calculated value multiplied by the correction coefficient. (1)...Digital tape measure body (2)...Vernier measure (4)...Measuring roller (5)
・°“Encoder (8)...Counter (9)
...Correction coefficient calculating means 0υ...Correction coefficient determining means (11)...Correction coefficient storage means q...Calculating means 04...Storage means U■...Display procedure correction form (method) ) 11 September 1980 ILF Date Patent Application No. 56872 2 Title of Invention Digital Tape Measure 3 Relationship to the Amendment Person Case Patent Applicant Address 24 Higashikujo Matsuda-cho, Minami-ku, Kyoto City δ, f1] Gatekeeper (1) Correct the patent applicant column in the application as shown in the attached sheet. (2) Supplement the document certifying the authority of representation as shown in the attached sheet. (3) Insert the following sentence after "This is a flowchart" on page 12, line 6 of the specification. ``Figure 6 is a diagram showing the state of use when performing inside tears using the digital tape measure of the embodiment.'' 9 List of attached documents

Claims (1)

[Claims] 1. A cave that is normally built in the case body and can be freely pulled out from the case opening when in use, and a measuring roller that converts the amount of movement of the cave into an amount of rotation;
an encoder that encodes the amount of rotation converted by the measuring roller; a counter that counts the output from the encoder; a calculation means that calculates the output of the counter during measurement; and a calculation result of the calculation means. In a digital tape measure consisting of a storage means for storing information and a display device for displaying the output of the calculation means or storage means, correction is made from the preset count number set in advance at the initial stage of measurement and the count output number counted by the counter. A means for calculating a coefficient, a determining means for determining whether the calculated correction coefficient is within an allowable range, and a correction coefficient storage means for storing the determined correction coefficient determined by the determining means. A digital tape measure featuring 2. The digital tape measure according to claim 1, wherein the calculation means calculates by adding the case body length when measuring the inside of a window frame or the like. 3. The digital tape measure according to claim 1 or 2, wherein the storage means for arranging the calculation results of the calculation means is a storage memory.