JPH07111386B2 - Membrane tension measurement method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the tension of a membrane, particularly a membrane constituting a membrane structure.

[0002]

2. Description of the Related Art In recent years, membrane structures have been actively constructed. In this membrane structure, a glass fiber cloth coated with a membrane such as Teflon (trade name of DuPont) is stretched between beams to form a roof or a wall. Aging causes the membrane to elongate, resulting in a decrease in membrane tension. In order to keep the membrane structure stable, it is preferable that the tension of the membrane, especially the membrane constituting the roof, be kept above a certain level, and therefore it is necessary to measure the tension of the membrane periodically.

[0003]

However, the conventional apparatus for measuring the membrane tension of the membrane structure is inconvenient to carry because of the large scale of the apparatus, and thus the workability is poor and the labor required for the measurement work is large. Become.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a film tension measuring method capable of measuring the film tension using a measuring device having a small device scale.

[0005]

In order to achieve this object, in the method for measuring the membrane tension of the present invention, in measuring the tension of the membrane constituting the membrane structure, a pressure sensor is attached to the tapping member. Is provided, the tapping member is caused to collide with a preliminary test film into which a known tension is introduced, and a characteristic amount of time that characterizes a dynamic change of the impact load generated in the tapping member based on the collision is determined based on the output of the pressure sensor. A characteristic amount of time is examined for each case in which a plurality of known tensions of different sizes detected and introduced into the preliminary test membrane are examined, and the correlation between these known tensions and the characteristic amount of time is examined in advance. Then, the tapping member is made to collide with the film to be measured whose tension is unknown to measure a characteristic amount of time, and the known magnitude of tension corresponding to this characteristic amount of time is set as the magnitude of tension of the film to be measured. Characterize.

[0006]

According to such a method, the tapping member is provided with the pressure sensor, and the tapping member is emitted from the initial position toward the film to collide with it. At this time, the pressure sensor detects a dynamic change of the impact load P generated on the tapping member, and a characteristic amount of time (hereinafter, in this specification, this characteristic is used to characterize the dynamic change of the impact load P based on the output of the pressure sensor). A characteristic amount of time is referred to as a characteristic amount T), for example, the time from the occurrence of the impact load P to its disappearance is detected.

For example, by setting the initial position of the tapping member with respect to the film and the acceleration applied to the tapping member at the time of emission to be constant, the magnitude of the tension introduced into the film and the characteristic amount T can be associated with each other.

Further, in order to carry out the present invention, a device for detecting the characteristic amount T is based on at least a tapping member and a pressure sensor, a mechanism for emitting the tapping member and a mechanism for returning to an initial position, and an output of the pressure sensor. And an electric circuit for detecting the characteristic amount T. Therefore, the device scale can be reduced. As such a device, for example, a conventionally known tapping-type peeling detection device can be used, and this conventional device is lightweight and small enough to be carried by one hand.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the drawings are merely schematic representations so that the present invention can be understood, and therefore the present invention is not limited to the illustrated examples.

In this embodiment, the characteristic amount T is detected by using a conventionally well-known tapping type separation detecting device. FIG. 1 is an explanatory view of the feature amount T detection principle in this embodiment, and is a view conceptually showing the output waveform of the pressure sensor and the dynamic behavior of the tapping member and the film. In the figure, the movement direction of the tapping member is indicated by an alternate long and short dash line arrow.

The tapping-type peeling detector used in this embodiment is a conventionally well-known device and is light and small enough to be carried by one hand. This device includes a tapping member 10 and a pressure sensor 12, a mechanism for ejecting the tapping member 10 and a mechanism for returning the tapping member 10 to the initial position S (not shown), and an electric circuit for detecting the characteristic amount T from the output of the pressure sensor 12. The display unit includes a CPU (including a CPU) and a detected feature amount T. The tapping member 10 has its axis P
A pressure sensor 12 is sandwiched between the members 10a and 10b divided into upper and lower layers. Reference numeral 14 indicates a film for forming a film structure.

First, the tapping member 10 is stopped and held at an initial position S separated from the film 14 by a predetermined distance t. Next, the tapping member 10 is emitted toward the surface of the film 14 and collides with the film 14 while making the axis P substantially parallel to the normal line of the surface of the film 14. At the time of this emission, the tapping member 10 may be naturally dropped, or the tapping member 10 may be dropped.
Alternatively, the acceleration may be given separately from the gravitational acceleration.

The output of the pressure sensor 12 rises when the tapping member 10 contacts the membrane 14 and increases until the tapping member 12 is in the maximum compressive load state. The output of the pressure sensor 12 decreases to zero after the maximum compression load state. From the output waveform of the pressure sensor 12,
It is possible to know the dynamic change (temporal change) of the impact load P generated in the tapping member 10. The characteristic amount T is a characteristic amount of time that characterizes the dynamic change of the impact load P, and in this example, the period T0 from the occurrence of the impact load P to its disappearance.
Time T1 required from the rise of the output of the pressure sensor 12 to the minimum output of the pressure sensor 12 within
Is. In addition to this, the period T0 may be used as the feature amount T.

Next, a preliminary test for examining the correlation A between the known tension and the characteristic amount T (time T1 in this example) will be described.
FIG. 2 is a diagram conceptually showing the correlation A between the time T1 and the known tension introduced into the membrane 14, in which the vertical axis represents the time T1 and the horizontal axis represents the known tension.

In the preliminary test, a plurality of known tensions having different sizes, for example, 2, 4, 6,
Five types of tension of 8 and 10 kg / cm are introduced into the membrane 14 as a preliminary test membrane. Then, in each case in which these different tensions are introduced, the tapping member 10 is made to collide with the film 14 and the time T1 is examined in the same manner as in the case of FIG. The correlation A with is obtained.

Next, the case of measuring the tension of unknown size introduced into the film to be measured will be described. After the investigation of the correlation A between the known tension and the time T1 as described above,
Similar to the case of FIG. 1, the tapping member 10 is made to collide with the film to be measured whose tension is unknown, and the time T1 of the film to be measured is measured. Then, by referring to the correlation A that has been checked in advance, the magnitude of the known tension corresponding to the time T1 of the measurement target film is detected as the magnitude of the tension of the measurement target film.

The correlation A may be recorded as a table, and the tension of the film to be measured may be checked by using the conventional tapping-type peel tester and the table of the correlation A.

In addition, the tension of the film to be measured is measured by a conventional tapping-type peeling tester, a memory for storing the correlation A, and an electric circuit for detecting a known tension corresponding to the time T1 of the film to be measured. You may make it comprise the tension measuring device to measure. A small and lightweight tension measuring device can be constructed by providing the conventional tapping type peeling tester with these memories and electric circuits.

The present invention is not limited to the above-mentioned embodiment, and therefore, the shape of each component, the arrangement position,
The dimensions and others can be arbitrarily changed.

[0020]

As is apparent from the above description, according to the film tension measuring method of the present invention, a pressure sensor is provided on the tapping member to measure the tension of the film constituting the film structure. A preliminary test film having a tension of a known magnitude is introduced to collide with the film, and a dynamic change of the impact load P generated on the tapping member at this time is detected by a pressure sensor. Then, based on the output of the pressure sensor, the characteristic amount T that characterizes the dynamic change of the impact load P, that is, the characteristic amount of time, is detected, and the correlation A between the magnitude of the known tension and the characteristic amount T is investigated in advance.

When measuring the tension of unknown magnitude introduced into the film to be measured, the tapping member is made to collide with the film to be measured, and the dynamic characteristic of the impact load P generated on the tapping member at this time is characterized. The quantity T is detected. Then, the magnitude of the known tension corresponding to this feature amount T is correlated with A
And the known magnitude of the tension is detected as the magnitude of the tension introduced into the film to be measured.

An apparatus for detecting such a characteristic amount T is based on at least a tapping member and a pressure sensor, a mechanism for emitting the tapping member and a mechanism for returning to an initial position, and an output amount of the pressure sensor. It suffices to have an electric circuit for detecting T, so that the device scale can be reduced. As such a device, for example, a conventionally known tapping-type peeling detection device can be used, and this conventional device is lightweight and small enough to be carried by one hand.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a feature amount detection principle.

FIG. 2 Correlation A between time T1 and known tension introduced in the membrane A
It is a figure which shows notionally.

[Explanation of symbols]

 10: Tapping member 12: Pressure sensor 14: Membrane

Claims (1)

[Claims] 1. When measuring the tension of a membrane constituting a membrane structure, a pressure sensor is provided on the tapping member, and the tapping member is caused to collide with a preliminary test membrane into which a known tension is introduced, and based on the collision. In each case, a characteristic amount of time that characterizes the dynamic change of the impact load generated in the tapping member is detected based on the output of the pressure sensor, and a plurality of known tensions of different sizes are introduced into the preliminary test membrane. The characteristic amount of time is examined, and the correlation between these known tensions and the characteristic amount of time is investigated in advance, and the characteristic amount of time is measured by colliding the tapping member with the film to be measured whose tension is unknown. Then, the known tension magnitude corresponding to the characteristic amount of time is set as the tension magnitude of the membrane to be measured.