JPH0223805B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field This invention converts the detected amount of movement of a measuring rod built into a case body and can be freely pulled out from the case opening into an electrical signal to measure the amount of movement. This invention relates to a digital tape measure that allows length results to be converted into any unit system and displayed digitally.

(b) Prior art In conventional digital tape measures, a movable measuring measure is pressed into contact with the circumference of a measuring roller, and a rotary encoder is connected to the rotating shaft of this measuring roller, which rotates as the measuring measure moves. The output of this counter was counted by a counter, the output of this counter was converted into an arbitrary unit system, and the result of the calculation was displayed on a digital display. In order to achieve this, it was necessary to increase the dimensional accuracy of the thickness of the measuring scale 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 amount of movement of the measuring rod will not match the digital display value. . Furthermore, the display error becomes large due to wear of the measuring scale and measuring roller due to long-term use.

(c) Purpose This invention was made 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 calculated measurement value multiplied by this correction coefficient is displayed. The purpose of the present invention is to provide a digital tape measure capable of accurately measuring and displaying data without being affected by processing errors or wear of the measuring tape due to changes over time.

(D) Configuration The digital tape measure according to the present invention measures the amount of movement of a measuring tape that is built into the case body and can be freely pulled out from the case opening and rotates as the measuring tape moves. The rotation amount is converted into a rotation amount by a roller, and the rotation amount is encoded by a rotary encoder connected to the rotation axis of this measuring roller.
In a digital tape measure in which the output of the rotary encoder is counted by a counter, the output of the counter is calculated by a calculation device, and the output of this calculation device is displayed by a display, the correction coefficient calculation mode and the length measurement mode are set as described above. A means for switching an arithmetic device is provided, and a setting is set on the arithmetic device in correspondence with the output value of the counter and its predetermined length when the measuring scale is pulled out from the case opening to a predetermined length scale in the correction coefficient calculation mode. A means for calculating a correction coefficient from the count number, and a determination means for determining whether the calculated correction coefficient is within a permissible range, and the determination means determines that the correction coefficient is within a permissible range. further comprising a correction coefficient storage means for storing the correction coefficient when the measurement is performed, and further comprising a calculation means for multiplying the output value of the counter by the correction coefficient in the length measurement mode and displaying the result on the display. It is characterized by

(E) 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 according to an embodiment of the present invention, and FIG. 2 is a sectional view. In FIG. 2, a measuring measure 2 wound around a reel having a spiral spring 3 is attached to the center of the case, and its tip is connected to a measuring measure 2 drawer opening via a measuring roller 4 in the middle. The measuring roller 4 has a measuring measure 2 along its circumference,
Furthermore, by applying pressure from the pressure roller 6, the tape is always moved while being pressed against the measurement roller 4 even when the tape is moved. The rotation of the measuring roller 4 results in the rotation of the rotary encoder 5 via a mechanically coupled axis.

FIG. 3 shows a functional block diagram for digitally displaying the output of the encoder 5. First, the direction of rotation of the two-phase output of the encoder 5 is determined by the direction determination circuit 7. Further, a counter 8 following the direction determining circuit 7 outputs a control signal that causes an addition (up) count if the measuring tape 2 is in the withdrawal direction, and a subtraction (down) count if the measuring tape 2 is in the storage direction. The count output from the counter 8 is input to the calculation means 12 in normal use, but in the initial state when the battery is set, the output of the counter 8 is input to the correction coefficient calculation means 9 and the correction coefficient determination means 1.
0 to the calculation means 12, and the correction coefficient at this time is stored in the correction coefficient storage means 11. Once the correction coefficient is stored, the above-mentioned normal usage status will occur thereafter. In the figure, the side a-a' shows the state of the battery set, and the side b-b' shows the state after the correction coefficient has been stored. In the calculation means 12, the count input from the counter 8 is multiplied by the value stored in the correction coefficient storage means 11, and a value is displayed on the display 15. The memory of the correction coefficient is not erased unless the battery is removed, so once it is set, it is a numerical value that can be used for a long period of 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 adding means 14 is used for the purpose of displaying a value obtained by adding the length of the case body to the result of the calculation during calculation. Also, storage means 13
The displayed numerical value can be temporarily stored and read out from the storage means 13 and displayed at a later time when necessary, and a storage memory is used that can be stored even when the power is turned off. The above configuration is configured as a control device 20 consisting of a microcomputer and its peripheral circuits, as shown in FIG. 4 (CPU diagram).

Next, the operation of the digital tape measure constructed as described above will be explained based on the flowchart shown in FIG. When you first set the batteries, all memories are cleared, and of course the correction coefficients are also cleared. In this state, a sign requesting correction (for example, CALIBRATION: CLb) is displayed on the display 15. Next, pull out the measuring scale 2 and set it at a predetermined position, e.g.
Pull it out to 2000mm and stop it so that measuring scale 2 cannot be moved. The number of input counts at this time is 2000 counts if the thickness of the measuring roller 4 and measuring scale 2 is an ideal value with no variation, but if the diameter of the measuring roller 4 is small and the tape drawer is 2000 mm, the input count will be 2000 counts. A larger value is entered. Conversely, if the roller diameter is large, the number of roller rotations will decrease even if the roller is pulled out by 2000 mm, and the input count number will be smaller than 2000 counts. The correction key 16 is used to correct this. Now, if the roller diameter is large and 1992 counts are input, when the correction key 16 is operated, the set count number (currently 2000) is input.
The input count number (1992) is calculated and K=1,
A correction coefficient of 004016 is calculated. If the value of K is within the range of normal correction operations and the error range that allows for the finishing of rollers, etc., then
The value of K falls within the range from the maximum value a' to the minimum value a set in the ROM and is stored in the RAM.
(Figure 5). If the correction operation is not normal or if the measuring scale 2 is not moving while being pressed against the measuring roller 4, the input count number will be too large or too small, and the value of K will also be larger than a' or a Since the correction becomes smaller and the correction is no longer accurate, an error is displayed on the display 15. In this case, the same operation may be repeated.

Next, when the value of K is stored, the value obtained by multiplying the input count number by the correction coefficient of K is displayed thereafter. (Figure 5). 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 value is expressed by the length of the measuring scale 2 protruding from the case exit, but when measuring inside the window frame 21, etc., the length of the measuring scale 2 is added to the length of the case itself. The value plus the length of 1 is required. So inside measurement key 17
is provided. The process up to multiplying the read value from the counter 8 by the correction coefficient K is as described above. Thereafter, when the inside length measurement key 17 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 measuring function, but the case main body 1 is provided with a number key, and the calculation means 12 calculates the input data from the number key and displays the result of the calculation. It may also be configured to have a calculation function; in such a case, it would be very convenient if the measurement results of each part of the object to be measured were memorized and various calculations such as hypotenuse calculation could be performed with one key operation. It is.

(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 measuring tape actually drawn out can be displayed correctly. Therefore, according to the present invention, there is no need for precision machining of the measuring thickness or the circumference of the measuring roller, thereby reducing processing costs, and reducing the effects of wear of the measuring scale, etc. due to changes over time, adhesion of dust, etc. This makes it possible to prevent the display accuracy from gradually decreasing.

[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 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. FIG. 6 is a diagram showing a state of use when performing inside measurement using the digital tape measure of the embodiment. 1...Digital tape measure body, 2...Measuring scale, 4...
Measuring roller, 5... Encoder, 8... Counter, 9... Correction coefficient calculating means, 10... Correction coefficient determining means, 11... Correction coefficient storage means, 12...
Arithmetic means, 13... Storage means, 15... Display device.

Claims (1)

[Scope of Claims] 1. A measuring scale that is normally built in the case body and can be freely pulled out from the case opening during use, and a measuring roller that converts the amount of movement of the measuring scale into an amount of rotation. , an encoder that encodes the amount of rotation converted by this measuring roller, a counter that counts the output from this encoder, an arithmetic device that performs required calculations based on the output from this counter, and a A digital tape measure comprising a display for displaying an output is provided with means for switching the arithmetic device between a correction coefficient calculation mode and a length measurement mode, and the arithmetic device has a means for switching the measuring device from the case opening in the correction coefficient calculation mode. means for calculating a correction coefficient from the output value of the counter when pulled out to a predetermined length scale and a set count number set corresponding to the predetermined length;
A correction coefficient storage means includes a determination means for determining whether or not the calculated correction coefficient is within the allowable range, and stores the correction coefficient when the determination means determines that the correction coefficient is within the allowable range. A digital tape measure, further comprising a calculation means for multiplying the output value of the counter by a correction coefficient in the length measurement mode and displaying the result on the display. 2. Storage means storing the case body length, and
Means is provided for switching the arithmetic device to an inside measurement mode for performing inside measurement of a window frame, etc.
Claims: The arithmetic device is provided with arithmetic means for multiplying the output value of the counter by a correction coefficient in the inside measurement mode, adding a value corresponding to the case body length stored in the storage means, and displaying the result on a display. The digital tape measure described in item 1. 3. The digital device according to claim 1 or 2, further comprising a storage means for storing the calculation results of the calculation device, the calculation device being configured using a microcomputer, and the storage device being a storage memory. Tape measure.