CN211375063U - Tool for measuring - Google Patents

Abstract

Embodiments of the present disclosure provide tools for measurement. The tool comprises: a tape measure unit for measuring a first length; a roller unit for measuring a second length by rolling with a roller, the second length being different from the first length, the roller unit including a roller; a ranging unit for measuring a first distance using laser, the ranging unit including a laser emitting unit and a laser receiving unit; and the power supply unit is connected with the roller unit and the distance measuring unit so as to provide electric energy for the roller unit and the distance measuring unit. The embodiment of the disclosure can give consideration to accurate measurement of ultra-long distance and curve length.

Description

Tool for measuring

Technical Field

The present disclosure relates to length or distance measurement, and more particularly, to tools for measurement.

Background

Conventional tools for measurement include, for example: tape measures and laser rangefinders. The scale part of the traditional measuring tape usually has rigidity, so that only straight line length can be accurately measured, and at least part of the length or distance of a curve cannot be accurately measured; in addition, since the length of the scale portion is limited, for example, typically 3 or 5 meters, it is difficult to measure an ultra-long length or distance. In addition, conventional laser rangefinders also do not accurately measure the length or distance of at least a portion of a curve.

Therefore, it is difficult for the conventional tool for measurement to accurately measure both an ultra-long distance and a curve length.

SUMMERY OF THE UTILITY MODEL

The present disclosure provides a tool for measurement that can compromise accurate measurement over long distances and curve lengths.

According to a first aspect of the present disclosure, a tool for measurement is provided. The tool comprises: a tape measure unit for measuring a first length; a roller unit for measuring a second length by rolling with a roller, the second length being different from the first length, the roller unit including a roller; a ranging unit for measuring a first distance using laser, the ranging unit including a laser emitting unit and a laser receiving unit; and the power supply unit is connected with the roller unit and the distance measuring unit so as to provide electric energy for the roller unit and the distance measuring unit.

In some embodiments, the tool further comprises a display unit for displaying at least one of the second length and the first distance; a processor coupled to the roller unit, the ranging unit and the display unit for at least one of: determining a first distance based on a time interval from emission of the laser pulse to detection of the laser pulse; the second length is determined based on the measurement result of the roller unit.

In some embodiments, the ranging unit comprises: the laser emitting unit is used for emitting laser pulses in response to the input signal of detecting the start of ranging, and the laser receiving unit is used for detecting the reflected laser pulses.

In some embodiments, the ranging unit comprises: a timing unit for determining a time interval from emission of the laser pulse to detection of the laser pulse.

In some embodiments, the tool further comprises: the mode switching key is connected with the processor and used for selecting a working mode of the tool by a user, and the working mode is any one of a roller measuring mode and a laser ranging mode;

in some embodiments, the tool further comprises: the ranging start switch is connected with the processor and used for triggering the input of ranging start by a user; and the power switch is connected with the power supply unit and is used for connecting or disconnecting the power supply unit with the distance measuring unit, the roller unit, the display unit and the processor.

In some embodiments, the tool further comprises: the display device comprises a first shell and a second shell, wherein the upper parts of the first shell and the second shell are provided with display units; and the first supporting piece is arranged between the first shell and the second shell, one side of the first supporting piece is provided with a tape measure unit and a roller unit, and the other side of the first supporting piece is provided with a distance measuring unit, a processor and a power supply unit.

In some embodiments, the tool further comprises: a locking device including a locking position and an unlocking position for locking or releasing the scale portion of the tape measure unit, the locking device being provided at an upper portion of the first and second housings.

In some embodiments, the tool further comprises: the bracket is used for supporting the roller; and the counting unit is used for detecting the rotation of the roller and comprises a Hall sensor.

In some embodiments, one of the first housing and the second housing includes an opening corresponding to positions of the laser light emitting window and the laser light receiving window of the ranging unit.

In some embodiments, the tool further comprises: the starting and measuring key is connected with the processor and used for connecting the power supply unit with the distance measuring unit, the roller unit, the display unit and the processor or used for triggering an input signal for starting distance measurement by a user; the roller measuring mode and the clearing key are connected with the processor, and the roller measuring mode and the clearing key are used for triggering the roller measuring mode or clearing the current measured value of the tool.

In some embodiments, the tool further comprises: the reference switching and unit switching key is connected with the processor and is used for determining the measurement basis of the laser ranging mode to be one of the front side and the rear side of the tool or determining the unit when the display unit displays at least one of the second length and the first distance; and the volume and area measurement mode switching key is connected with the processor and is used for determining that the measurement mode of the tool is one of a volume measurement mode and an area measurement mode.

The summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. The summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure.

Drawings

The foregoing and other objects, features and advantages of the disclosure will be apparent from the following more particular descriptions of exemplary embodiments of the disclosure as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the disclosure.

Fig. 1 shows a schematic view of a tool 100 for measurement according to an embodiment of the present disclosure;

fig. 2 shows an exploded view of a tool 200 for measurement according to an embodiment of the present disclosure;

fig. 3 shows a schematic diagram of a ranging system 300 according to an embodiment of the present disclosure;

FIG. 4 shows a side view of a tool 400 for measuring according to an embodiment of the present disclosure;

FIG. 5 shows another side view of a tool 500 for measuring according to an embodiment of the present disclosure; and

fig. 6 shows a schematic diagram of an input unit 600 according to an embodiment of the present disclosure.

Like or corresponding reference characters designate like or corresponding parts throughout the several views.

Detailed Description

Preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure.

In describing embodiments of the present disclosure, the terms "include" and its derivatives should be interpreted as being inclusive, i.e., "including but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first," "second," and the like may refer to different or the same object. Other explicit and implicit definitions are also possible below. The terms "connected" and "coupled" are to be construed to cover a fixed connection, a removable connection, an integral connection, a direct connection, and an indirect connection.

As described above, in the conventional solution for measuring, since the scale portion of the tape measure has certain rigidity and a limited length, it is difficult to accurately measure an ultra-long straight length or a curved length; the laser distance measuring instrument is a straight line based on the measuring path of the laser, and the length of the curve cannot be accurately measured. Therefore, it is difficult for the conventional tool for measurement to accurately measure both an ultra-long distance and a curve length.

To address, at least in part, one or more of the above issues and other potential issues, an example embodiment of the present disclosure presents a tool for measurement. In this aspect, the tool comprises: a tape measure unit for measuring a first length; a roller unit for measuring a second length by rolling with a roller, the second length being different from the first length, the roller unit including a roller; a ranging unit for measuring a first distance using laser, the ranging unit including a laser emitting unit and a laser receiving unit; and the power supply unit is connected with the roller unit and the distance measuring unit so as to provide electric energy for the roller unit and the distance measuring unit.

In the above scheme, by configuring the roller unit in the tool to measure the length including the curve and configuring the distance measuring unit based on the laser to measure the ultra-long distance, the general straight-line length can be measured by the tape unit, and simultaneously, the ultra-long distance and the curve length can be accurately measured.

Fig. 1 shows a schematic view of a tool 100 for measurement according to an embodiment of the present disclosure. As shown in fig. 1, the tool 100 for measuring includes a tape measure unit 110, a roller unit 120, a distance measuring unit 130, and a power supply unit 140. Wherein the tape measure unit 110 is used to measure the first length. The roller unit 120 is used to measure a second length different from the first length by rolling with a roller, and the roller unit 120 includes a roller. The ranging unit 130 is for measuring a first distance using laser light, the ranging unit 130 includes at least: a laser emitting unit and a laser receiving unit (not shown in fig. 1). The power supply unit 140 is connected to the wheel unit 120 and the distance measuring unit 130 to supply power to the wheel unit 120 and the distance measuring unit 130. In some embodiments, the tool 100 further comprises: a processor 150, and a display unit 160 and an input unit 170 connected to the processor 150. In some embodiments, the tool 100 further comprises a communication unit for transmitting the measurement values of the tape measure unit 110, the roller unit 120, the ranging unit 130 and/or at least one of the first length, the second length and the first distance to a user terminal (not shown).

The tape measure unit 110 comprises, for example, a scale portion and a reel. The scale portion may be wound on a reel. The first length is, for example, a straight length and is less than or equal to a predetermined measurement threshold (the predetermined measurement threshold being an upper limit of a measurement range of the scale portion of the tape measure unit 110, e.g. 3 meters, 5 meters, 12 meters, etc.). In some embodiments, the scale portion is an elongated strip of metal material having some rigidity.

The second length measured by the roller unit 120 is a path through which the roller rolls. The second length may be a straight line or may include a curved line. In some embodiments, the entire second length is curvilinear. In some embodiments, at least a portion of the second length is curvilinear. By simultaneously configuring the roller unit 120 in the tool 100, the tool 100 can measure a straight length through the tape unit 110 while measuring a length including a curve.

The ranging unit 130 measures a first distance of the tool 100 to the object to be measured, for example, using laser pulses. The first distance is for example a predetermined measurement threshold, for example several tens of meters, greater than the first length. The ranging unit 130 includes a laser emitting unit for emitting a laser pulse in response to detection of an input signal of a start of ranging; the ranging unit 130 includes a laser receiving unit for detecting the reflected laser pulses. In some embodiments, the ranging unit 130 further comprises a timing unit for determining the time interval from emission of a laser pulse to detection of the laser pulse. By configuring the tape unit 110, the roller unit 120, and the distance measuring unit 130 in the tool 100 at the same time, the tool 100 can be made to allow for measurement of an extra long distance far beyond the upper limit of the measuring range of the scale portion of the tape unit 110 by the distance measuring unit 130 in addition to measurement of a straight length by the tape unit 110 and measurement of a length including a curve by the roller unit 120.

In some embodiments, the power supply unit 140 is, for example and without limitation, a battery, which is connected to the wheel unit 120, the distance measuring unit 130, the processor 150, the display unit 160, and the input unit 170 to supply power to the above units. In some embodiments, the power supply unit 140 may be a lithium battery. In some embodiments, the power supply unit 140 may be powered by an external power source.

Regarding the processor 150, in some embodiments, it is connected to the wheel unit 120, the distance measuring unit 130, the display unit 160, and the input unit 170 for determining a first distance based on a time interval from the emission of the laser pulse to the detection of the laser pulse; and determines the second length based on the measurement result of the wheel unit 120. The processor 150 may also transmit the calculated second length and/or first distance to the display unit 160 so that the display unit 160 displays the second length and/or first distance. In some embodiments, the display unit 160 may also display the first length measured by the tape measure unit 110. In some embodiments, the processor 150 is also used for receiving an input signal input by a user via the input unit 170.

The input unit 170 is used to acquire an input signal of a user. In some embodiments, the input unit 170 includes, for example, a plurality of key switches, such as: a mode switch, a ranging start switch and a power switch. The mode selector switch is used, for example, for the user to select an operation mode of the tool (the operation mode is, for example, "wheel measurement mode" or "laser ranging mode"). The ranging start switch is used, for example, for a user to trigger an input of ranging start. The power switch is connected with the power supply unit and used for connecting or disconnecting the power supply unit with the distance measuring unit, the roller unit, the display unit and the processor.

In some embodiments, the input unit 170 includes, for example, four keys, as shown in fig. 6. Fig. 6 shows a schematic diagram of an input unit 600 according to an embodiment of the present disclosure. In fig. 6, the input unit 600 includes, for example: a power-on and measurement button 610, a wheel measurement mode and clear button 620, a reference switch and unit switch button 630, and a volume and area measurement mode switch button 640. The power-on and measurement button 610 is used to turn on the power supply of the power supply unit or an input signal for the user to trigger the start of ranging. For example, pressing the one-time power-on and measurement button 610 to turn on the power supply of the power supply unit; the power on and measurement button 610 is pressed once more in the tool power on state for the user to trigger ranging to start. The wheel measurement mode and clear button 620 is used to trigger the wheel measurement mode or clear the current measurement value of the tool. For example, long press of the wheel measurement mode and clear button 620 are used to trigger the wheel measurement mode; the short press of the wheel measurement mode and clear button 620 is used to clear the current measurement of the tool. The reference switching and unit switching key 630 is used to switch the measurement reference of the laser ranging mode to the front side and the rear side of the tool (when switching to the rear side, the measurement result includes the length of the tool itself, i.e., the distance from the front side to the rear side of the tool) or to switch the display unit (e.g., meters or feet) of the measurement result. For example, the reference switching and unit switching key 630 is pressed once for laser ranging with the front side of the tool as a measurement reference; pressing the two-time reference switching and unit switching key 630 is used for performing laser ranging with the rear side of the tool as a measurement reference; the long press reference switching and unit switching key 630 is used to switch the display unit of the measurement result to meter or the like. The volume/area measurement mode switch button 640 is used for switching between the volume measurement mode and the area measurement mode based on the measurement result of the laser ranging mode. For example, pressing the volume area measurement mode switch key 640 twice is used to record and calculate the most recent result (e.g., length and width, respectively) measured by the laser ranging mode as an area; pressing the volume area measurement mode switch button 640 twice is used to record and calculate the three results (e.g., length, width, and height, respectively) most recently measured by the laser ranging mode as a volume. In the above embodiment, by connecting each key included in the input unit 600 to the processor, the processor obtains the input signal of the user via each key based on the number of times each key is pressed (for example, pressed once, twice or three times) and the pressed state (for example, pressed for a long time or a short time), and then controls the corresponding distance measuring unit, power supply unit or scroll wheel unit to perform corresponding operation or measurement.

In the scheme, the roller unit and the distance measuring unit are arranged in the tool, so that the length can be measured through the tape measure, and meanwhile, the ultra-long distance and the curve length can be accurately measured. Thus, the user can take account of the requirements of various measurement scenarios only by carrying the tool 100, and does not need to carry various different measurement tools.

The specific structure of the measurement tool according to the embodiment of the present disclosure is described below with reference to fig. 2. Fig. 2 shows an exploded view of a tool 200 for measurement according to an embodiment of the present disclosure. As shown in fig. 2, the tool 200 includes a first housing 270, a second housing 280, a tape measure unit 210, a roller unit 220, a distance measuring unit 230, a battery 240, a circuit board 250 (on which a processor is disposed), a display screen 260, a locking device 292, and a first support 290.

In some embodiments, the upper portions of the first and second housings 270 and 280 are provided with a display unit (e.g., a display screen 260). A mode switching switch 272, a ranging start switch 274, and a power switch 276 for user operation are provided on the outer side of the first housing 270 (for example, the left side of the first housing 270 in fig. 2). In some embodiments, the front side of the first housing 270 is also provided with an opening 278. The position of the opening 278 corresponds to the position of the laser light emitting window 232 and the laser light receiving window 234 of the ranging unit 230 for providing a passage for the laser light (e.g., laser light pulses) emitted and received by the ranging unit 230. In some embodiments, the aperture 278 may be provided on the second housing 280.

The tape measure unit 210 comprises a reel and a scale portion (not shown) wound on the reel. The scale portion is, for example, an elongate strip of metallic material (e.g. without limitation, steel material) with scale indicating markings. In some embodiments, the scale portion is coated with a coating for protecting the scale indication. A reel around which the scale portion is wound is rotatably mounted at one side of the first support 290. The reel may be rotated about its central axis as the scale section is being pulled out or retracted. In some embodiments, the first length measured by the tape measure unit 210 is sent to the display screen 260 to display the measurement of the tape measure unit 210.

In some embodiments, the tool 200 further comprises a locking device 292, the locking device 292 comprising a locked position and an unlocked position for locking or releasing the scale portion of the tape measure unit 210. A locking device 292 is disposed at an upper portion of the first and second housings 270 and 280, and in some embodiments, the locking device 292 includes a locking member 294 shown in fig. 3.

The first support 290 is disposed between the first case 270 and the second case 280. In some embodiments, the tape measure unit 210 and the roller unit 220 are disposed on one side of the first support 290. For example, the tape measure unit 210 is disposed above the roller unit 220. The roller unit 220 is disposed at a lower portion of the first support 290. In some embodiments, the other side of the first support is provided with a ranging unit 230, a circuit board 250 (in which a processor is configured), and a power supply unit (e.g., a battery 240). In some embodiments, an opening is further provided below the first and second housings 270 and 280, through which at least a portion of the roller 224 of the roller unit 220 is exposed outside the first and second housings 270 and 280 to roll along the surface of the object to be measured.

The roller unit 220 is used to measure the second length based on the stroke of the roller. The roller unit 220 includes, for example, a roller 224, a bracket 222, and a counting unit (not shown). The roller 224 is fixed to the bracket 222, for example, by a shaft. The counting unit is used for sensing the rotation of the roller 224 and further calculating the stroke of the roller 224. In some embodiments, the counting unit inputs a count value indicative of the rotation of the wheel 224 into the processor, calculates the second length from the processor, and sends the calculated second length to the display 260 for display. The counting unit may sense the rotation of the wheel 224 in various ways. In some embodiments, the counting unit may include a hall sensor and a magnet. In some embodiments, the counting unit may comprise a grating disk and a photocell. In some embodiments, the support 222 is configured with a resilient element to cushion the roller 222 from impacts due to irregularities in the surface of the object being measured. In some embodiments, the rollers 224 are also provided with anti-slip structures, as shown in FIG. 4.

In some embodiments, the ranging unit 230 includes, for example: laser emission unit, laser receiving element, timing circuit. The laser emitting unit includes, for example: laser diode, emission drive circuit, laser emission window 232. The laser receiving unit includes, for example: laser detection element, laser receiving window 234.

The ranging manner of the ranging unit is described below with reference to fig. 3. Fig. 3 shows a schematic diagram of a ranging system 300 according to an embodiment of the present disclosure. As shown in fig. 3, the ranging system 300 includes an object 360 to be measured, a ranging unit 310, a processor 350, and an input unit 370. The ranging unit 310 further includes: laser emitting unit 320, laser receiving unit 330, timing circuit 340. The processor 350 of the ranging system 300 calculates the first distance based on, for example, the following equation (1).

D＝T*V/2 (1)

In the above formula (1), D represents the first distance. The first distance is, for example, the distance from the ranging unit 310 to the target 360 to be measured. V represents the speed at which the laser pulse propagates in air. T represents the time from the emission of the laser pulse to the detection of the laser pulse by the laser receiving unit.

In some embodiments, the measurement method of ranging system 300 is, for example: when the processor 350 detects that the user presses the ranging start key in the input unit 370, the laser emitting unit 320 is triggered to emit a laser pulse with a short duration, the laser pulse is emitted from the laser emitting window 232 shown in fig. 2, and after passing through the distance D to be measured, the laser pulse is reflected by the target 360 to be measured, and the reflected laser pulse is detected by the photodetector (e.g., laser detecting element) of the laser receiving unit 330 via the laser receiving window 234 shown in fig. 2. The processor calculates the distance D from the ranging unit 310 to the object 360 to be measured according to the above formula (1) based on the time interval T from the emission of the laser light to the detection of the reflected laser light pulse by the laser detecting element.

The above-mentioned time interval T can be obtained in various ways. In some embodiments, the time interval T between the emission of laser light and the detection of the reflected laser light pulses by the laser detection element may be calculated by the timing circuit 340. In some embodiments, processor 350 records the time T1 at which the laser pulse was emitted in response to detecting that the user pressed the ranging start key; then, in response to the detection of the reflected laser pulse by the laser detection element, the receiving time T2 is recorded, and the distance D from the ranging unit 310 to the target 360 is determined based on the time interval T between the emitting time T1 and the receiving time T2. In some embodiments, the time interval T from laser emission until the reflected laser pulse is detected back by the photodetector may be determined based on the wavelength of the modulated light and the angular frequency of the modulated signal by amplitude modulating the laser beam and determining the phase delay caused by the modulated light going back and forth a single time.

Fig. 4 shows a side view of a tool 400 for measurement according to an embodiment of the present disclosure. As shown in fig. 4, a laser emission window 410, a laser reception window 412, and a roller unit 420 are disposed at the front sides of a first case 430 and a second case 440. The display unit 450 is disposed at an upper portion of the first case 430 and the second case 440.

Fig. 5 illustrates another side view of a tool 500 for measuring according to an embodiment of the present disclosure. As shown in fig. 5, the tool 500 is provided with an output opening 520 of the scale portion and a locking means 510. The output opening 520 and the locking device 510 are disposed at the rear side of the first and second housings 430 and 440, i.e., the opposite side to the side where the laser emission window 410 and the laser reception window 412 are disposed.

Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

The above are merely alternative embodiments of the present disclosure and are not intended to limit the present disclosure, which may be modified and varied by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims (12)

1. A tool for measurement, characterized in that the tool comprises:

a tape measure unit for measuring a first length;

a roller unit for measuring a second length by rolling with a roller, the second length being different from the first length, the roller unit including the roller;

a ranging unit for measuring a first distance using laser, the ranging unit including a laser emitting unit and a laser receiving unit; and

and the power supply unit is connected with the roller unit and the distance measuring unit so as to provide electric energy for the roller unit and the distance measuring unit.

2. The tool of claim 1, wherein the tool further comprises:

a display unit for displaying at least one of the second length and the first distance;

a processor coupled to the roller unit, the ranging unit, and the display unit for at least one of:

determining the first distance based on a time interval from emission of the laser pulse to detection of the laser pulse; and

determining the second length based on a measurement result of the wheel unit.

3. The tool of claim 1, wherein the laser emitting unit is configured to emit a laser pulse in response to detecting an input signal of a start of a ranging, and the laser receiving unit is configured to detect the reflected laser pulse.

4. The tool of claim 3, wherein the ranging unit further comprises:

a timing unit for determining a time interval from emission of the laser pulse to detection of the laser pulse.

5. The tool of claim 2, wherein the tool further comprises:

and the mode switching switch is connected with the processor and used for selecting the working mode of the tool by a user, and the working mode is any one of a roller measuring mode and a laser ranging mode.

6. The tool of claim 5, further comprising:

the ranging start switch is connected with the processor and is used for triggering an input signal for starting ranging by a user;

and the power switch is connected with the power supply unit and is used for switching on or switching off the power supply unit and the distance measuring unit, the roller unit, the display unit and the processor.

7. The tool of claim 2, wherein the tool further comprises:

the display device comprises a first shell and a second shell, wherein the display unit is arranged on the upper parts of the first shell and the second shell; and

the first support piece is arranged between the first shell and the second shell, the tape measure unit and the roller unit are arranged on one side of the first support piece, and the distance measuring unit, the processor and the power supply unit are arranged on the other side of the first support piece.

8. The tool of claim 7, further comprising:

a locking device comprising a locked position and an unlocked position for locking or releasing the scale portion of the tape measure unit, the locking device being provided at an upper portion of the first and second housings.

9. The tool of claim 8, wherein the roller unit further comprises:

the bracket is used for supporting the roller; and

and the counting unit is used for detecting the rotation of the roller and comprises a Hall sensor.

10. The tool of claim 9, wherein one of the first housing and the second housing includes an opening corresponding to the positions of a laser emitting window and a laser receiving window of the ranging unit.

11. The tool of claim 2, wherein the tool further comprises:

the starting and measuring key is connected with the processor and used for connecting the power supply unit with the distance measuring unit, the roller unit, the display unit and the processor or used for triggering an input signal for starting distance measurement by a user;

the roller measuring mode and the clearing key are connected with the processor and used for triggering the roller measuring mode or clearing the current measured value of the tool.

12. The tool of claim 11, wherein the tool further comprises:

a reference switch and unit switch key connected to the processor, the reference switch and unit switch key being configured to determine a measurement basis of a laser ranging mode to be one of a front side and a rear side of the tool, or to determine a unit at which the display unit displays at least one of the second length and the first distance; and

and the volume and area measurement mode switching key is connected with the processor and is used for determining that the measurement mode of the tool is one of a volume measurement mode and an area measurement mode.

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