JP2003057136A - Tensile force measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make easily computable a tensile force by measuring a load corresponding to a specified amount of bending in the case of measuring a belt tensile force on the basis of the amount of bending of a stretched belt and the load. SOLUTION: This tensile force measuring apparatus is provided with reference plate 2 with a contact 5 and a pressure sensor 3 at a center as a pressure sensing part and has reference parts 21 and 22 at both ends. When the contact 5 is pressed against the belt to be measured to bend the belt, the reference parts 21 and 22 come into contact with the belt when the amount of bending takes a specified value. Therefore, the output of the pressure sensor 3 at this time represents the load that causes the bending of the specified value. On the basis of the load value, the amount of bending of the specified value, and a known span (the distance between the reference parts 21 and 22), it is possible to compute the belt tensile force through the use of a known tensile force arithmetic expression.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension measuring device, and more particularly to a tension measuring device suitable for easily measuring the tension of a belt or the like stretched around a mechanical device.

[0002]

Belt devices for transmitting power and conveying articles are widely used in industry. In the belt device in which the tension value of the belt applied to the mechanical device is not set as planned, power cannot be transmitted efficiently or the article cannot be stably conveyed. Also, if the proper tension that matches the characteristics of the belt is not applied,
There is a problem that the life of the belt itself is shortened and the frequency of replacement is increased.

In order to set the belt tension to a proper value, it is first necessary to accurately measure the belt tension. As a belt tension measuring method, a method is known in which a load is applied to a belt stretched around a mechanical device and the tension is measured based on the amount of bending of the belt at that time.

For example, in Japanese Unexamined Patent Publication No. 9-250961, a substrate having a length at least exceeding the span of the pulley is arranged along the outer circumference of the belt stretched between two pulleys, and the belt is placed on the substrate. A belt tension measuring device equipped with a pressing means and a belt bending amount measuring means is disclosed.
In this tension measuring device, a flexure amount measuring sleeve that slides in the belt pressing direction is arranged in a holder provided on a substrate, and a pressing means that slides in the belt pressing direction is arranged in the flexure amount measuring sleeve. It is arranged. The operator can determine the belt tension by reading the relative positions of the holder, the deflection amount measuring sleeve, and the pressing means when the measuring device is pressed against the belt.

Generally, the tension T of a belt stretched between two points
Is calculated using the following equation. T≈F × S / 4d ... Equation (1). However, S is a distance (span) between two points, d is a bending amount, and F is a load applied to the belt. If the tension T obtained by this equation is appropriately corrected according to the material and shape of the belt, a more accurate tension can be obtained. The correction value is determined by experiments or the like.

[0006]

In the above tension measuring device, the operator can judge the tension on the basis of the pressing force and the bending amount of the belt, but it cannot immediately judge the accurate tension value. Further, the belt tension is calculated by the above formula (1).
However, in order to obtain the tension with high accuracy, it is desirable to be able to recognize the pressing force corresponding to the predetermined reference bending amount or the bending amount corresponding to the predetermined pressing force.

In view of the above demands, the present invention has an object to provide a tension measuring device capable of recognizing accurate tension simply by pressing the tension measuring device against an object to be measured.

[0008]

SUMMARY OF THE INVENTION The present invention for solving the above problems and achieving the object is to apply a load to a stretched elongated object and to bend the elongated object in the load direction. In the tension measuring device configured to calculate the tension based on, the reference point set at the apex position of the triangle is formed so as to abut all of the long object when the long object is deflected by a predetermined amount. A reference member, a sensor arranged at one of the reference points of the reference member, for detecting a load applied to the reference point from the outside of the triangle, and the contact of the sensor pressing the long object, A detection value of the sensor when all of the reference points come into contact with the elongated object, a distance between two reference points other than the reference point where the sensor is arranged, and a line connecting the two reference points are defined. The tension is based on the height of the triangle when the bottom is The first characteristic is that the apparatus is provided with a tension calculation means for calculating the tension of a long object.

The present invention further comprises switch means for producing an output when all of the reference points come into contact with the elongated object, and the detection output of the sensor is output in response to the output of the switch means. A second feature is that the tension calculation means is configured to be input.

According to the first and second characteristics, when the contact of the sensor is pressed against the long object which is the object to be measured and all the reference points come into contact with the long object, the position of the reference point A predetermined amount of bending is generated in the long object depending on the relationship. Therefore, the detection output of the sensor when this amount of deflection occurs,
In other words, the tension value is calculated by the tension calculation means based on the load that has caused the predetermined amount of bending of the long object.

In particular, according to the second feature, when all the reference points come into contact with the long object, that is, when the predetermined bending is applied, the switch means generates an output, and the sensor output is automatically output. Can be captured.

Further, the present invention is a tension measuring device configured to apply a load to a stretched elongated object and calculate a tension based on a bending amount of the elongated object in the load direction, A reference plate having a length equal to or longer than the tension span of the long object, a contactor provided in the center of the reference plate and capable of displacing a predetermined amount in the vertical direction of the reference plate, and a pressure receiving portion on the contactor. With the sensor for detecting the load received by the contactor being coupled and the reference plate being spanned between the tension spans, the contactor was displaced by the predetermined amount in order to bend the elongated object. A third feature is that the apparatus includes a tension calculation unit that calculates the tension of the stretched elongated object based on the detected value of the sensor, the displacement of the predetermined amount, and the tension span. .

Further, the present invention has a fourth characteristic in that the reference plate is provided with a scale along the length direction of the reference plate.

According to the third and fourth characteristics, if the reference plate is spanned between the stretched spans, for example, between the pulleys on which the belt is stretched, and the contact is displaced to the movable limit, the reference plate is stretched. A predetermined amount of bending can be generated in a long object based on the above. Therefore, the tension calculation means calculates the tension value based on the load at that time. According to the fourth feature, by using the scale, it is possible to arrange the reference plate so that the contactor is located at the center of the span and accurately apply the load to the center of the span.

Further, the present invention has a fifth feature in that it is provided with a display means for displaying the tension value calculated by the tension calculation means. According to the fifth feature, the user can visually recognize the calculated tension value.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of a tension sensor according to an embodiment of the present invention, and FIG. 2 is a bottom view. In both figures,
The tension sensor 1 includes a reference plate 2, a pressure sensor 3 mounted on the lower surface of the reference plate 2, and a cover 4 that covers the pressure sensor 3 from the lower surface. The reference member, that is, the reference plate 2, is a support portion 2 that supports the pressure sensor 3 and the cover 4 at the center in the longitudinal direction.
0 and the reference portions 21 protruding downward at both ends of the support portion 20,
And 22.

The pressure sensor 3 can be composed of a piezoresistive element that exhibits a resistance change due to mechanical stress. The pressure sensor 3 has a pressure receiving portion 30, and the pressure receiving portion 30 has the pressure receiving portion 30.
The contactor 5 for transmitting the pressure is engaged. Contact 5
Has a taper on its side surface, and this taper surface engages with the taper surface formed on the cover 4. Since the contactor 5 is engaged with the tapered surface, it can be ejected upward with respect to the cover 4, but cannot be ejected downward. Also,
The tips (lower ends) of the contacts 5 are set so as to project from the cover 4. A switch 6 is provided on the upper surface of the support portion 20, and the output line 31 of the pressure sensor 3 is connected to a control device described later via the switch 6.

FIG. 3 shows a main part of the tension sensor 1 (A in FIG. 1).
FIG. 4 is a perspective view of the contactor 5. The pressure receiving portion 30 of the pressure sensor 3 is a columnar protrusion and engages with a cylindrical recess 50 formed on the upper surface of the contact 5. Between the concave portion 50 of the contactor 5 and the lower end of the pressure receiving portion 30, a contactor 5 is provided so that a gap G is formed when the contactor 5 is lowered by gravity.
And the shape of the cover 4 that receives the contactor 5 on the tapered surface TP are set. By forming the gap G, it is possible to prevent the pressure from being applied to the pressure sensor 3 when the contact 5 is not pressed against the measurement object.

The lower end of each of the reference portions 21 and 22 is a contactor 5.
The downward projection amount is set so as to be positioned above the lower end of the dimension by a dimension d. In addition, the lower end surfaces of the reference portions 21 and 22 are angled so that the lower end of the contactor 5 (the lower end in the state where the gap G is closed) is located at the intersection of both extension lines in the center direction of the support portion 20 (Fig. 1)).

FIG. 5 is a front view showing a belt tension measuring mode by the tension sensor 1. In FIG. 5, the belt device 7 is composed of a pair of pulleys 8 and 9 and a belt 10 wound around these pulleys 8 and 9. In the present embodiment, the tension sensor 1 is attached to the belt 10 of the belt device 7 from the outer peripheral direction.
When the contact 5 of the belt 10 is pressed,
When it comes into contact with, the switch 6 is turned on to take the output signal of the pressure sensor 3 into the control device. Reference part 21,2
Since 2 is retracted from the contact 5 (retraction amount = d),
As shown in FIG. 5, when the belt 10 is displaced inward by the bending amount d, both the reference portions 21 and 22 come into contact with the belt 10. Therefore, both of the reference portions 21 and 22 are the belt 1
0 output signal of the pressure sensor 3 (contact force F
Based on the known dimension d and the distance S between the reference portions 21 and 22, the formula (1) shown in the section “Prior Art”
Can be used to calculate the tension of the belt 10.

FIG. 6 is a block diagram showing the function of the controller for calculating the tension. The control device 100 can be configured by a microcomputer, and has a tension calculation unit 11 and a deflection amount storage unit 1.
2, a distance storage unit 13, and a display control unit 14. The signal (pressing force F) detected by the pressure sensor 3 is input to the tension calculator 11 via the switch 6. The flexure amount d is stored in the flexure amount storage unit 12, and the reference unit 2 is stored in the distance storage unit 13.
The distance between 1 and 22 is stored. The tension calculation unit 11 calculates the tension T using the equation (1) based on the deflection amount d, the distance S, and the detected pressing force F input from both the storage units 12 and 13. The calculated tension T is input to the display control unit 14, and the display control unit 14 performs data conversion of the tension value in order to display the tension T on the display unit 15 in a predetermined form.
Output to 5. The display unit 15 can be composed of, for example, a liquid crystal display unit.

The tension calculation unit 11 and the deflection amount storage unit 1
Instead of 2 and the distance storage unit 13, a table that stores the correspondence relationship between the tension T and the pressing force F may be provided, and the tension T may be read from this table using the pressing force F as a key.

The tension calculation unit 11 can have a storage area for storing a plurality of calculation results of the tension T and a means for calculating an average of a plurality of tension values stored in this storage area. For example, the measurement procedure may be repeated a plurality of times, and the average value of the tension values T for a plurality of times obtained as a result may be output to the display control unit 14 as the tension value of the belt. This makes it possible to eliminate the bias in the measured values.

Instead of storing the tension T a plurality of times, a plurality of detection values of the pressure sensor 3 may be stored and the average value thereof may be used to calculate the tension T. Also,
Instead of calculating the average value, the tension can be calculated by appropriately adopting a well-known statistical method for eliminating the deviation of the measurement results.

Although the switch 6 is operated by a person, it may be a switch means that operates automatically. Figure 7
FIG. 6 is a cross-sectional view of a reference portion 21 having an automatic switch. A recess 16 is formed on the lower end surface of each of the reference portions 21 and 22, and a micro switch 17 is embedded in the recess 16 so that the tip of the movable portion projects. If the micro switches 17 provided in the reference portions 21 and 22 are connected in series to replace the switch 6, the output of the pressure sensor 3 is automatically output when both the reference surfaces 21 and 22 come into contact with the belt 10. The tension is taken into the tension calculation unit 11 and the tension is calculated. Of course, an element that operates on the same principle as the pressure sensor 3 may be used instead of the micro switch 17.

Next, a second embodiment of the present invention will be described.
8 and 9 are front views of the belt device and the tension sensor according to the second embodiment, and FIG. 10 is a plan view. In particular, FIG. 9 is a diagram when a predetermined amount of bending is applied to the belt by applying a load. In these figures, the tension sensor 1A
Has a reference plate 23 having a sufficient length L that spans the spans of the pulleys 8 and 9, and the reference plate 23 can be displaced in the front facing direction of the belt 10 with respect to a hole 231 formed in the center thereof. A contact 24 is provided. The contact 24 is fixed to the pressure receiving portion 30 of the pressure sensor 3 located above the contact 24.
The pressure sensor 3 can use a piezoresistive element in the same manner as described with reference to FIG.

The pressure sensor 3 is provided above the hole 231 and is housed in the pressure sensor holding portion 232 having a diameter larger than the upper edge diameter of the hole 231. Belt 10 for tension sensor 1A
When contacted with, the contact 24 is pushed upward, and the distance d between the lower surface of the pressure sensor 3 and the upper surface of the hole 231 is increased.
Is formed. When the upper surface of the pressure sensor 3 is biased from the position where the tension sensor 1A is brought into contact with the belt 10 and the contact 24 is pressed against the belt until the lower surface edge of the pressure sensor 3 comes into contact with the upper surface edge of the hole 231, The belt 10 bends inward, and the amount of bending at the center of its span corresponds to the distance d.

For example, graduations 25 in 1 cm increments can be provided on the upper edge of the reference plate 23 so that it can be confirmed that the contactor 24 is located at the center of the pulleys 8 and 9.
Further, as the reference plate 23, one having a different distance d may be used depending on the belt type and the span of the pulley.

FIG. 11 is a front view of a modification of the tension sensor 1 described above. In the tension sensor 1B according to this modification, the pressure sensor 3 is housed in the reference plate 2, and the handle 26 is provided so as to be convenient for pressing the reference plate 2 against the measurement target. The handle 26 is coupled to the reference plate 2 via a hinge 27 provided near the center of the reference plate 2, that is, above the pressure sensor 3. As shown by the chain line V, the handle 26 is
When not in use, the hinge 27 is rotated to rotate the reference plate 2
Can be folded along.

The size of the handle 26 is determined so that it can be easily grasped by a person, and it is preferable that the handle 26 accommodates the board constituting the control unit described with reference to FIG. 6 and the battery serving as the control power source. . Further, a liquid crystal panel as the display 15 can be provided on the front surface.

In the above embodiment, the present invention has been described by taking the belt tension measurement as an example. However, the applicable range of the tension measuring device of the present invention is not limited to this, and it can be applied to the tension measurement of various long objects such as a belt, which is tensioned between two points, as well as cables, wires, strings and the like. it can.

[0032]

As is apparent from the above description, according to the inventions of claims 1 to 5, it is possible to give a predetermined amount of bending to the object to be measured, and at that time, the bending occurs. The tension can be calculated by taking in the applied load as a sensor output. Therefore, the operator simply causes the calculation means to calculate the tension by a simple and reliable procedure of pressing the reference member or the reference plate provided with the sensor capable of detecting the load against the long object as the measurement object. To be In particular, according to the invention of claim 5, the tension calculation result can be visually recognized.

[Brief description of drawings]

FIG. 1 is a front view showing a main configuration of a tension measuring device according to a first embodiment of the present invention.

FIG. 2 is a bottom view showing the main configuration of the tension measuring device according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a main part of the tension measuring device.

FIG. 4 is a perspective view showing a contact of a pressure sensor, which is a main part of the tension sensor.

FIG. 5 is a diagram showing a mode of tension measurement by the tension measuring device according to the first embodiment of the present invention.

FIG. 6 is a functional block diagram of a main part of a control unit of the tension measuring device.

FIG. 7 is a cross-sectional view of a main part of a tension sensor showing an attachment mode of a switch that senses contact with a reference point.

FIG. 8 is a front view showing a main configuration of a tension measuring device according to a second embodiment of the present invention.

FIG. 9 is a front view showing a configuration of a main part of a tension measuring device in a weighted state by a contactor.

FIG. 10 is a plan view showing a main configuration of a tension measuring device according to a second embodiment of the present invention.

FIG. 11 is a front view according to a modified example of the present invention.

[Explanation of symbols]

1, 1A ... Tension sensor, 2, 23 ... Reference plate, 3 ... Pressure sensor, 4 ... Cover, 5, 24 ... Contact, 6 ...
Switch, 7 ... Belt device, 8, 9 ... Pulley, 1
0 ... Belt, 11 ... Tension calculation unit, 15 ... Indicator,
17 ... Micro switch, 20 ... Support part, 21, 2
2 ... Standard part

Claims (5)

[Claims] 1. A tension measuring device configured to apply a load to a stretched elongated object and calculate a tension based on a bending amount of the elongated object in the load direction. A reference member formed so that all the reference points set at the apex positions of the triangles when they are deflected by a predetermined amount are in contact with the elongated object, and the reference member is arranged at one of the reference points of the reference member. A sensor that detects a load applied from the outside of the triangle, and presses the long object with the contact of the sensor, and the detection value of the sensor when all of the reference points are in contact with the long object, The long object stretched based on the distance between two reference points other than the reference point where the sensor is arranged and the height of the triangle when the line connecting the two reference points is the base. And a tension calculation means for calculating the tension of Tension measuring device. 2. A switch means for producing an output when all of the reference points come into contact with the elongated object, and the detection output of the sensor is sent to the tension calculating means in response to the output of the switch means. The tension measuring device according to claim 1, wherein the tension measuring device is configured to input. 3. A tension measuring device configured to apply a load to a stretched elongated object and calculate a tension based on a bending amount of the elongated object in the load direction. A reference plate having a length equal to or greater than the tension span, a contact provided in the center of the reference plate and capable of displacing a predetermined amount in the vertical direction of the reference plate, and a pressure receiving portion coupled to the contact. A sensor that detects the load received by the contactor, and the sensor when the contactor is displaced by the predetermined amount in order to bend the elongated object in a state in which the reference plate is spanned between the tension spans. And a tension calculation means for calculating the tension of the stretched elongated object based on the detected value, the predetermined amount of displacement, and the tension span. 4. The tension measuring device according to claim 3, wherein the reference plate is provided with a scale along a length direction of the reference plate. 5. A display means for displaying the tension value calculated by the tension calculation means is provided.
The tension measuring device according to any one of to 4.