JPS6239923B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pointer or recording pen driving device for converting a received pneumatic signal into a displacement of the pointer and indicating or recording a physical quantity to be measured in a pneumatic meter.

As shown in FIG. 1, the drive mechanism of this type of recording pen, which has been commonly used in the past, has an input bellows 2 and a drive bellows 3 disposed opposite to each other on both sides of a base 1, and the movable ends of both bellows 2 and 3 are A lever 4 whose one end is fixed to the base 1 via cross supports 6 and 7,
A feedback spring 8 is connected between the free ends of both levers 4 and 5, and a nozzle flapper mechanism is constituted by the other end of the lever 4 and the nozzle 9. It is communicated with the drive bellows 3.

In the pen drive mechanism as described above, when the input signal Pi is applied to the input bellows 2, the movable end of the input bellows 2 is displaced and the lever 4 is moved to the fulcrum 6.
Tilt counterclockwise around the center. When the lever 4 is tilted, the gap between the nozzle 9 and the nozzle 9 becomes smaller, so the nozzle back pressure increases, and the movable end of the drive bellows 3 is displaced to tilt the lever 5 clockwise, thereby increasing the input signal.
It stops at the position where Pi and nozzle back pressure are balanced. At this time, if a recording pen d is connected to one end of the lever 5, the magnitude of the input signal Pi can be recorded.

By the way, in the conventional pen drive mechanism configured in this way, levers 4 and 5 and fulcrums 6 and 7 are required to take out the displacement of input bellows 2 and drive bellows 3, and both levers 4 and 5 are Since the input bellows 2 and the drive bellows 3 are tilted as they are displaced, it is necessary to pivot the ends of both bellows 2 and 3, which makes manufacturing extremely troublesome.
Another problem is that it is necessary to take measures such as making the feedback spring 8 longer to avoid the influence of spring inclination. Furthermore, the link mechanism connected to such a recording pen drive mechanism to record changes in input signals on recording paper and its range adjustment mechanism are extremely complex and have many drawbacks, such as being troublesome to adjust. Ta.

The present invention was made in order to solve the above-mentioned conventional problems, and an object of the present invention is to provide a pen drive mechanism that is simple in structure, easy to manufacture, and essentially free of non-linear errors. That is.

Another object of the present invention is to simplify the configuration of a pen arm for recording a change in an input signal on a recording paper by extracting the displacement of a drive bellows of a pen drive mechanism, and to record without the need for complicated link adjustment. Provides a pen drive.

Still another object of the present invention is to provide a recording pen drive device in which range adjustment of a pen arm is extremely easy.

The present invention will be explained below using the drawings.

FIG. 2 is a theoretical vertical sectional view of the pen drive mechanism according to the present invention. In the figure, 11 is the base, 21
is an input bellows, one end of which is fixed to the base 11, and an input signal Pi is applied through a passage 12 provided in the base 11. Reference numeral 31 denotes a balanced beam, which consists of a beam body 32, a cross spring fulcrum 33, and a flap part 34, and the fixed part of the fulcrum 33 is attached to the base 11.
is fixed. 42 is a nozzle, base 11
The nozzle flapper mechanism 41 is configured with the flapper portion 34 of the balance beam 31. Reference numeral 51 denotes a drive bellows mechanism, which is composed of a drive bellows 52, a bottomed cylindrical guide 53, and a guide rod 55 fitted into the guide 53 with a clearance fit.
The bottom part 54 of 3 is attached to the base 11, and the guide rod 55
One end of each is fixed to the movable end of the drive bellows 52, respectively. A rod 56 has one end fixed to the movable end of the drive bellows 52, and is used to extract the displacement of the drive bellows 52 to the outside as necessary.

61 is a feedback spring, one end of which is connected to the movable end of the drive bellows 52, and the other end of which is connected to the balance beam 3.
1, respectively. 71 is a zero adjustment spring, 72 is a zero adjustment screw, 13 is an inlet for supply pressure Ps, 14 is a passage leading to the drive bellows mechanism 51,
15 is a passage leading to the nozzle 42, and the supply pressure Ps supplied from the inlet 13 is applied to the nozzle 42 and the drive bellows 52 via the fixed throttle 16.
Create nozzle back pressure.

Next, the operation of the pen drive mechanism configured as described above will be explained. When an input pressure Pi is introduced into the input bellows 21, the input pressure Pi is converted into a force and a clockwise moment about the fulcrum 33 is generated in the balance beam 31. Due to this moment, the tip of the balance beam 31, that is, the flapper part 34, decreases the gap with the nozzle 42, so that the nozzle back pressure increases, and this increase in nozzle back pressure is guided to the drive bellows 52, which moves the bellows Generates force at the end. This force causes the feedback spring 6 to
1 is compressed, imparting a force on the balance beam 31 that is proportional to the amount of compression (and therefore the amount of displacement of the drive bellows 52). This force results in a counterclockwise moment of the balance beam 31 about the fulcrum 33, balancing the moment caused by the input pressure Pi.

In this case, if the effective area of the drive bellows 52 and the spring constant of the feedback spring 61 are appropriately selected, the displacement of the drive bellows 52 corresponding to the input pressure Pi can be extracted with high accuracy.

Generally, the center of the mechanical spring of the bellows does not coincide with the center of area. Therefore, to the extent that a coil spring is disposed opposite the movable end of the bellows, the bellows does not displace linearly, but expands while tilting as the input pressure increases. This slope is quite large, and experiments have confirmed that it exceeds the adjustable range. In the pen drive mechanism according to the present invention, by adding a guide 53 and a guide rod 55 as linear guides, it has become possible to accurately detect the displacement of the bellows.

FIG. 3 is a block diagram of a main part of an embodiment in which the present invention is implemented in a pneumatic recording instrument, in which a is a side view, b is a plan view of the driving bellows mechanism, and c is a left side view. Note that parts having the same functions as those in FIG. 2 are denoted by the same reference numerals, and explanations thereof will be omitted. Reference numeral 57 denotes a pen arm drive pin provided at the movable end of the drive bellows 52 so as to be rotatable in the circumferential direction. Reference numeral 81 denotes a pen arm, and this pen arm 81 has a small arm 82 that is constantly connected to the drive pin 57 by being biased by a spring (not shown).
and a large arm 83 whose axis is perpendicular to the small arm 82, and is pivotably fixed at the intersection 0 of both arms 82, 83. Further, a notch groove 84 is provided at the tip of the large arm 83, and this notch groove 84 is connected to a pin 87 of a paint cartridge 86 that is slidably inserted through a guide 85.

As is well known, the bellows can only move about 5 mm, so it must be enlarged in order to extract and record this displacement. A link mechanism is generally used as an enlargement mechanism, but in order to obtain a linearity of 0.2 to 0.3% with the link mechanism, extremely complicated link adjustment is required.

In the present invention, the linear movement of the drive bellows 52 is utilized to cause the small arm 82 and large arm 83 of the pen arm 81 to move in a similar manner. That is, as shown in FIG. 4, the rotation center 0 of the small arm 82 and the drive pin 57
It is characterized in that the triangle AOB formed by the displacement trajectory A-B of the large arm 83 and the triangle COD formed by the rotation center 0 of the large arm 83 and the displacement trajectory CD of the pin 87 of the paint cartridge 86 are made similar.

The linearity of the recording pen device is determined by the feedback spring, and in the present invention, a non-linearity element using a link mechanism does not intervene, resulting in a mechanism that does not require linearity adjustment.
Note that small nonlinear elements appear due to changes in the nozzle flapper mechanism and the effective area of the bellows that enter the forward circuit, but these are corrected by a large loop gain.

By the way, various methods have been implemented or proposed for adjusting the range in the recording pen drive device of a pneumatic meter, but all of them have extremely complicated structures and are difficult to adjust.
In the present invention, the drive pin 57 provided at the movable end of the drive bellows 52 is rotated around the drive bellows 52 as shown in FIG.
By changing the contact position with the small arm 82
The magnification ratio can be changed by changing the effective length of the lens, making it extremely easy to adjust the range.

FIG. 5 is a side view of essential parts of an embodiment in which the present invention is applied to a two-pen recording instrument, showing a first pen drive mechanism consisting of a balance beam 31, a drive bellows 52, a feedback spring 61, etc., and a balance beam. 31
a. A second pen drive mechanism consisting of a drive bellows 52a, a feedback spring 61a, etc. is arranged in parallel facing the opposite direction, and drives the small arms 82, 82a of the pen arms 81, 81a, which are pivoted at the intersection 0, respectively. It is connected to pins 57 and 57a. With this configuration, two different
Each of the two input air pressure signals can be recorded on the recording paper channel. Note that if two more sets of pen drive mechanisms are placed behind both of the pen drive mechanisms described above (on the right side of the figure), four input air pressure signals can be recorded. In this case, although the large arm of the recording pen provided at the rear becomes longer, each input air pressure signal can be recorded with high precision by adjusting the magnification rate using the range adjustment mechanism described above.

In the above description, the guide of the drive bellows mechanism 51 is configured by the guide 53 and the guide rod 55 disposed inside the drive bellows 52, but the present invention is not limited to this, and the guide is provided by the drive bellows 52. The guide may be provided outside of the guide bellows 52 as long as the drive bellows 52 is displaced linearly. Further, although the present invention has been described as being applied to an indicator or recorder of a pneumatic instrument, it goes without saying that it can also be applied to a ribbon drive device of a ribbon indicator.

As described in detail above, the pen drive mechanism according to the present invention is composed of a balanced beam that generates a moment based on an input signal and nozzle back pressure, a drive bellows that performs linear motion, a feedback spring, etc. There is no need for two levers that perform a large tilting displacement like a mechanism, two bellows having a pivot that abuts the levers, and a feedback spring that is affected by tilting. This not only simplifies the manufacturing of the structure, but also substantially improves accuracy since there is essentially no non-linear error.

In addition, the pen arm that extracts and magnifies changes in the input signal and records them on the recording paper is composed of a small arm and a large arm, and both arms are made to perform similar movements, making the configuration simple and eliminating the need for complex link adjustment. does not require. Further, range adjustment is extremely easy as it is only necessary to rotate the drive pin provided on the drive bellows, and the effects of implementation are great.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of an example of a conventional pneumatic pen drive mechanism, Fig. 2 is a cross-sectional view of the principle configuration of the present invention, Fig. 3 a is a side view of the main parts of an embodiment of the present invention, and b
4 is a plan view of the driving bellows mechanism portion, c is a left side view, FIG. 4 is an explanatory view showing the locus of the pen arm, and FIG. 5 is a side view showing the main parts of another embodiment of the present invention. 11: Base, 21: Input bellows, 31: Balance beam, 32: Beam body, 33: Fulcrum, 3
4: flapper part, 41: nozzle flapper mechanism,
42: Nozzle, 51: Drive bellows mechanism, 52:
Drive bellows, 53: guide, 55: guide rod,
57: Pen drive pin, 61: Feedback spring, 81: Pen arm, 82: Small arm, 8
3: Large arm, 86: Pen cartridge, 87: Pin.

Claims (1)

[Scope of Claims] 1. An input bellows is coupled to one side of a fulcrum of a balanced beam, and a feedback spring coupled to a drive bellows that performs linear motion by nozzle back pressure is coupled to the other side, respectively, The small arm and the large arm are arranged at right angles, and the intersection point of the pen arm is rotatably fixed, and the small arm of the pen arm is connected to the movable end of the drive bellows, so that the small arm and the large arm make similar movements. A pen drive device for a pneumatic instrument, which is characterized by: 2. A pen drive mechanism that has an input bellows on one side of the fulcrum of the balanced beam, and a feedback spring coupled to a drive bellows that performs linear motion due to nozzle back pressure on the other side, and a small arm. and a pen arm in which a large arm is arranged at right angles and the intersection thereof is pivotably fixed, and a pen drive pin is provided at the movable end of the drive bellows so as to be rotatable in the circumferential direction. A pen drive device for a pneumatic instrument, characterized in that a small arm is connected and the effective length of the small arm is changed by rotating the drive pin to adjust the range.