JPS6357838B2 - - Google Patents

Description

[Detailed description of the invention] Technical field The present invention relates to a front metal gas meter.

BACKGROUND TECHNOLOGY A front-metal gas meter is installed in the middle of a city gas transmission pipe, and allows gas to flow through by inserting objects such as coins into it, thereby dispensing an amount of gas corresponding to the number of objects inserted. It makes it possible to use it.

FIG. 1 shows a typical prior art and is a simplified front view of the structure of a part of a conventional front-metal gas meter. By manual operation following the input of the input material, the rotating shaft 1 and the disc cam 2 fixed to the rotating shaft 1 are moved in the clockwise direction 3 shown by the solid line. The amount of angular displacement of this forward movement is proportional to the number of input items and is an angle of less than 360 degrees. A pin-shaped follower 4 is fixed to one end of the arm 5.
This arm 5 is pivoted in a fixed position by a pin 6. Arm 5 is fixed to another arm 7. This arm 7 is connected to an on-off valve interposed in the middle of the gas flow path. This arm 7 is given a spring force in the direction of arrow 8, and therefore the follower 4 is given a spring force radially inward of the cam 2.

When the follower 4 is fitted into the recess 9 of the cam 2, the valve is in a closed state. When the rotation shaft 1 is rotated in the forward movement direction 3 by a manual operation subsequent to the insertion of a coin, the follower 4 is moved radially outward along the recess cam surface 10 of the recess 9. The state shown in the first diagram is reached. Furthermore, as the cam 2 is rotated in the forward movement direction 3, the follower 4
moves onto the arcuate cam surface 11. When the follower 4 is on the arcuate cam surface 11, the valve is in an open state, allowing the use of gas. As gas is used, the gas metering means causes the rotation shaft 1 and the cam 2 to
is gradually angularly displaced and returned in the counterclockwise backward movement direction 12 indicated by the dashed arrow.

At the end of the gas use, the follower 4 moves to the arcuate cam surface 1.
1 along the recess cam surface 10 of the recess 9;
The follower 4 fits into the recess 9 and the valve is closed, completing the use of the predetermined amount of gas.

The recessed cam surface 10 extends radially inwardly of the cam 2 and forward in the forward movement direction 3 at an angle α with the radial direction of the cam 2 . As a result, when the cam 2 is angularly displaced in the forward movement direction 3, the follower 4 fitted into the recess 9 is displaced radially outward from the recess 9 and escapes from the recess 9 to form a circular arc. Cam surface 11
It will be possible to move to. The fact that the recess cam surface 10 has to have an angle α causes the following problems.

FIG. 2 is a graph showing the gas flow rate characteristics of the front metal gas meter in the prior art shown in FIG.
When the follower 4 is on the arcuate cam surface 11, the flow rate is constant as shown by line 13. At the end of gas use, while the follower 4 is fitting into the recess 9 along the recess cam surface 10, the gap between the valve body and the valve seat of the valve gradually becomes smaller. Therefore, as shown by line 14, the flow rate of gas used decreases over time, and theoretically, a minute amount of gas continues to flow forever. Therefore, it takes time to measure the gas flow rate. Furthermore, when the gas metering means malfunctions, it may become difficult to accurately measure minute flow rates. Therefore, it is desired to realize a front metal gas meter having a flow rate characteristic that abruptly shuts off the flow as shown in FIG. 2.

Problems to be Solved by the Invention An object of the present invention is to provide a front metal gas meter in which the valve means has a flow rate characteristic that abruptly shuts off as shown in FIG.

Means for Solving the Problems The present invention has a recess that is reciprocatingly angularly displaced around an axis and is recessed in the radial direction, and a recess release cam surface is formed at the rear of the recess in the forward movement direction. The recess release cam surface has a first cam that extends radially inward and forward in the forward movement direction forming a first angle β with the radial direction, and the first cam is coaxially movable with respect to each other. It has a recess that is pivotally supported and recessed inward in the radial direction, and a recess fitting surface is formed at the rear of the recess in the forward movement direction,
a second cam having an arcuate cam surface continuous in the circumferential direction from the radially outer end of the recess-fitting surface; and a follower to which a spring force is applied radially inward to the first cam and the second cam. The amount of mutual allowable angular displacement between the first cam and the second cam is such that when the first cam is at the forwardmost position in the forward movement direction relative to the second cam, the recess-fitting surface is detached from the recess. When the first cam is at the frontmost position in the backward movement direction relative to the second cam, the radially outer end of the recess-fitting surface is the first cam. Located in the recess of the cam, the first
The range is selected to be less than the maximum angular displacement of the cam, and the recessed recessed cam surface can be transferred to the arcuate cam surface when the follower is removed from the recessed area by the angular displacement of the first cam in the forward movement direction. The recess-fitting surface has a radial direction of the second cam and a second cam facing forward in the forward movement direction toward the radially inward side of the second cam.
extending at an angle γ, the second angle γ being selected to be less than or equal to the first angle β, further interposed in the middle of the gas flow path and interlocking with the follower;
a valve means that is in a closed state when the follower is fitted into the recesses of the first and second cams and is in an open state when the follower is on the arcuate cam surface of the second cam; The rotational power from the handle is transmitted to the first cam via the rotated handle and the input object, whereby the first cam is rotated in the forward movement direction, so that the follower is separated from the recessed recessed cam surface. gas flowing through the valve means, such that upon completion of rotation of the handle, the input material falls and the transmission of rotational power from the handle to the first cam is interrupted; This is a front metal type gas meter characterized by comprising means for measuring the usage amount of the first cam and driving the first cam in the backward movement direction.

Embodiment FIG. 3 is an exploded perspective view of a part of the structure of a front metal gas meter according to an embodiment of the present invention. With this structure shown in the third figure, the valve 21
It has the function of opening the valve and keeping it open so that only a predetermined amount of gas is supplied. The input material inputted from the input port 23 of the input guide member 22 is
The handle 24 is received within a slit 27 formed in a receiving member 25 and a receiving key member 26 to which the handle 24 is secured. Then, move the handle 24 in the direction of the arrow 28.
By rotating it 180 degrees, this rotational power is transmitted to the receiving key member 26 via the input material,
The receiving key member 26 is rotated 180 degrees. By rotating the handle 24 and the receiving member 25 through 180 degrees,
The input items in the slit 27 fall and are stored in a storage box (not shown). The handle 24 and the receiving member 25 are returned to their original positions by the torsion spring 29. The receiving key member 26 is integrally provided with a gear 30 and a cam plate 31. The pawl 32 which engages the cam plate 31 is biased by a spring in the direction of the arrow 33, thereby allowing the receiver key member 26 to rotate accurately through 180 degrees. The gear 30 is
It is interlocked with a planetary gear unit 36 via gears 34 and 35.

FIG. 4 shows the planetary gear device 36 and the cam device 2.
FIG. Referring to this figure in conjunction with FIG.
Fixed to 9. Sun gear 38 and ring gear 39
A pair of planetary gears 40 that mesh with the internal teeth of the cylindrical gear 40 are pivotally supported by a support plate 41 . This support plate 41 is interlocked with the cam device 20 via a rotation shaft 42 integrated therewith. An indicator needle 43 is fixed to the free end of the rotation shaft 42. Rotational power from the metering means 44 having a rotational speed proportional to the amount of gas used is transmitted to the external teeth of the ring gear 39 via a gear train 45, and the ring gear 39 is rotationally driven. The measuring means 44 is
For example, the reciprocating motion of the metering membrane due to gas pressure is converted into rotational motion by a crank mechanism, and this rotational motion is transmitted to the gear train 45.

A valve 21 is provided near the inlet of the front metal gas meter. In this valve 21, a valve seat 47 facing upstream in the gas flow direction 46 is formed in the gas flow path, and a valve body 48 is provided upstream of the valve seat 47 in the gas flow direction 46. The valve body 48 is configured to be elastically biased by a conical spring 49 in the direction of seating on the valve seat 47 . Conical spring 4
The axis of the spring 9 coincides with the axis of the valve body 48 , and the small diameter end of the conical spring 49 is connected to the valve body 48 . The valve stem 50, which is integral with the valve body 48, is inserted into the guide hole 5 of the cylinder 51.
Guided by 2. A contact piece 53 is fixed to the lower end of the valve stem 50. This contact piece 53 has a spherical contact portion 55 formed at the tip of the arm 54.
comes into contact. The arm 54 is connected to a link mechanism 60 that includes an arm 57 to which a follower 56 of the cam device 20 is fixed at one end, a pivot 58 and another arm 59 .

FIG. 5 is a front view of the cam device 20 according to an embodiment of the present invention, showing various operating states. This cam device 2
6 and 7, respectively. The first cam 61 is fixed to the rotating shaft 42 . This first cam 61 is formed into a circular flat plate shape and has a recess 63 that is recessed inward in the radial direction. The recess 63 has a recess release cam surface 65 at the rear in the forward movement direction 64 indicated by a solid arrow, and the recess release cam surface 65 extends radially inward and forward in the forward movement direction 64. , the angle that this recess release cam surface 65 forms with the radial direction of the first cam 61 is indicated by the reference symbol β.

In the second cam 62, the rotation shaft 42 is loosely fitted into the shaft hole 70, and a recess 66 is also formed in the second cam 62, and a recess fitting surface is formed behind the recess 66 in the forward movement direction 64. 67 is formed. This recess fitting surface 6
7 extends radially inward of the second cam 62 and forward in the forward movement direction 64, and this recess fitting surface 67 forms an angle γ with the radial direction of the second cam 62. In this example, β=γ, but in the present invention, β
It is sufficient if ≧γ>0. An arcuate cam surface 69 is formed continuously in the circumferential direction from the radially outer end 68 of this recess-fitting surface 67 . In this way, the second cam 62 is also formed into a substantially circular plate shape.

The radius R1 of the first cam 61 is smaller than the radius R2 of the second cam 64 (R1<R2), so when the first cam 61 and the second cam 62 are overlapped coaxially,
The second cam 61 is located radially outward from the outer peripheral surface of the first cam 61.
An arcuate cam surface 69 of the cam 62 is located there.

A pair of elongated holes 71 are bored in the first cam 61 and extend in the circumferential direction on the same virtual circumference, for example, at positions shifted by 180 degrees in the circumferential direction. On the surface of the second cam 62 facing the first cam 61, a pair of locking pins 72 that pass through the elongated hole 71 are erected on a diameter line. When the locking pin 72 is in contact with the rearmost end 74 of the elongated hole 71 in the forward movement direction 64, that is, the first cam 61 is at the forwardmost position in the forward movement direction 64 relative to the second cam 62. At one time, the recess entry surface 67 is in a position equal to the recess exit cam surface 65, in other words, the recess exit cam surface 65
and the recess fitting surface 67 are flush with each other. As another embodiment of the present invention, the first cam 61 is connected to the second cam 6.
2, the recess fitting surface 67 is at the forwardmost position in the forward movement direction 64 relative to the recess removal cam surface 6.
5 in the forward movement direction 64. In the illustrated embodiment, the recess detachment cam surface 65 and the recess insertion surface 67 can be flush with each other, so that the recess 6
When the first cam 61 and the second cam 62 rotate in the forward movement direction 64 as described later, the follower 56 recessed in the recesses 63, 66 corresponds to
66 to the arcuate cam surface 69 smoothly.

When the locking pin 72 is in contact with the rearmost end 73 of the long hole 71 in the backward movement direction 75 opposite to the forward movement direction 64, that is, when the first cam 61 is in contact with the second cam 6
2, the recess fitting surface 67 is in the range 76 of the recess 63 of the first cam 61 (see FIG. 6). Long hole 7
The range 77 of angles within which the locking pin 72 can move is the relative allowable range of angles between the first cam 61 and the second cam 62. This angle range 7
7 is at least less than the maximum angular displacement amount of the rotation shaft 42 and therefore the first cam 61, so that when the rotation shaft 42 and the first cam 61 rotate,
The second cam 62 rotates when the locking pin 72 hits the rear end 74 of the elongated hole 71 in the forward movement direction 64, and the follower 5
6 is allowed to separate from the recesses 63 and 66 and reach the arcuate cam surface 69 of the second cam 62.

When the follower 56 fitted into the recesses 63 and 66 is displaced radially outward along the recess release cam surface 65, the recess release cam surface 65 is configured to have a first
With the angular displacement of the cam 61 in the forward movement direction 64, the second
This allows the cam 62 to be transferred from the recess fitting surface 67 to the arcuate cam surface 69. Recess 6 of second cam 62
6, a portion facing the recess fitting surface 67 is a guide portion 78 projecting outward in the radial direction,
Thereby, the follower 56 can be reliably fitted into the recess 66 from the arcuate cam surface 69, and the follower 56 can be prevented from going beyond the recess 66 from the arcuate cam surface 69.

By manual operation of the handle 24, the receiver key member 26 is rotated 180 degrees through the input, and the gears 30, 34, 35, rotation shaft 37, sun gear 38, and planet gear 40 are rotated accordingly by the solid line arrow. are rotated in the respective directions. In accordance with the revolution of the planetary gear 40, the rotation shaft 42 rotates, the indicator needle 43 indicates the number of items to be thrown, and the first cam 61 is rotated in the forward movement direction 64. The follower 56 is shown in FIG.
As shown, the first cam 61 and the second cam 62
The valve 21 is pre-immersed in the bottoms of the recesses 63 and 66, thereby closing the valve 21. At this time, when the rotation shaft 42 and therefore the first cam 61 are rotated,
The follower 56 has the above-mentioned angle β of the recess release cam surface 65.
It moves radially outward along this recess exit cam surface 65 and also along the recess entry surface 67 in this embodiment. In this way, as shown in FIG. 5, the follower 5
6 will be transferred to the arcuate cam surface 69 of the second cam 62. Therefore, the arm 57, the pivot 58 and the arm 59 are displaced in the direction of the solid arrow in FIG. 3, whereby the abutment piece 55 lifts the valve stem 50. Therefore, the valve body 48 separates from the valve seat 47 against the spring force of the conical spring 49, and the valve 21 becomes open.

When the valve 21 is opened and gas is used, the ring gear 39 is rotationally driven in the direction of the dashed arrow in FIG. 3 by the rotational power from the metering means 44 that measures the amount used. Therefore, the rotation shaft 42 and the first
The cam 61 is driven to reverse rotation in the backward movement direction 75 indicated by the dashed arrow. The second cam 62 is pressed against the locking pin 72 as shown in FIG.
remains stationary until it comes into contact with the rearmost end 73 of the elongated hole 71 in the backward movement direction 75, and then the second cam 62
is angularly displaced in the backward movement direction 75 together with the first cam 61. In this way, depending on the use of gas, when the follower 56 further reaches the recess insertion surface 67 from the connection point 68 between the circular arc cam surface 69 and the recess insertion surface 67, the radius of the second cam 62 by the follower 56 Due to the spring force in the inward direction, the follower 56 abuts against the recess-fitting surface 67, which is inclined at an angle γ as seen in FIG.
A force component acts on the cam 62 in the backward movement direction 75, and the second cam rotates in the backward movement direction 75. Therefore, after the follower 56 contacts the outer end 68, the recesses 63, 66
It suddenly fits in and settles at the bottom of the recesses 63 and 66.
As a result, the lever 54 is rotated by the conical spring 49 in the direction of the dashed arrow in FIG.
0 and the valve body 48 are displaced downward, and the valve body 48 is seated on the valve seat 47 to be in the valve closed state. Holoa 56
When the follower 5 is immersed in the recesses 63 and 66, the follower 5
6 is in contact with the recess release cam surface 65. Therefore, when the rotating shaft 42 and the first cam 61 rotate in the forward movement direction 64, the follower 56 radially moves along the recess release cam surface 65. It becomes possible to move outward.

In the front metal gas meter of the above-described embodiment, the gas flow rate characteristics are as shown in FIG. 2, and the valve is abruptly shut off at the end of gas use. Therefore, even if the gas metering means fails to operate below a certain relatively small flow rate, the front metal gas meter can reliably shut off the gas without any problems. Gas can be accurately measured in accordance with the number of items to be introduced. In this way, the problems of the prior art described in connection with FIG. 21 are solved.

As an embodiment of the present invention, the first cam 61 may be provided with a locking pin 72, and the second cam 62 may be provided with an elongated hole 71. The first cam 61 and the second cam 62 may be cams having other structures such as grooved cams. The combination of the elongated hole 71 and the locking pin 72 is similar to the above-mentioned embodiment.
The first cam 61 and the second cam 61 do not necessarily have to be on one diameter line of the second cam, and may be a single combination.
It is sufficient that the configuration is such that the mutual angular displacement with the cam 62 is allowed within the above-mentioned angular range. 1st
Although the shapes of the cam 61 and the second cam 62 are approximately circular in the above-described embodiment, they are not intended to be limited to this shape, and of course may have other shapes. be. As another embodiment of the present invention, the recess fitting surface 67 of the second cam 62 is formed in the state shown in FIG. , may be located behind the recess detachment cam surface 65 in the forward movement direction 64, so that when the first cam 61 is rotated in the forward movement direction 64, the follower 56 moves toward the recess separation cam surface 65. The first cam 61 can be moved radially outwardly along the first cam 61 . Furthermore, the fifth
From the state of FIG. 3, the first cam 61 and the second cam 62
When further angularly displaced in the backward movement direction 75, the recess fitting surface 67 has a shape in which the follower 56 suddenly retracts from the radially outer end 68 of the recess fitting surface 67 into the recess 63 of the first cam 61. All you need is Hollow 56
There is no need to angularly displace the second cam 62 backward by the return movement 75 when the second cam 62 hits the recess fitting surface 67. 1st cam 6
The bottom of the first recess 63 is formed to be equal to or shallower than the bottom of the recess 66 of the second cam 62.

As described above, according to the present invention, when the first cam and the second cam are angularly displaced in the backward movement direction, when the follower reaches the vicinity of the recess, the second cam is moved radially inward by the follower. The spring force causes the follower to retract into the recess by rapidly displacing the second cam in the backward movement direction until the follower abuts the recess exit cam surface. Since the recess release cam surface extends radially inward of the first cam and forward in the forward movement direction,
By rotating the first cam in the forward movement direction,
The follower can move radially outward along the recessed exit cam surface to the arcuate cam surface of the second cam.

In this manner, the present invention can provide a front metal gas meter having a flow rate characteristic in which the valve means suddenly shuts off, as shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a front view of a part of the prior art, FIG. 2 is a graph showing gas flow characteristics of the front metal gas meter of the prior art and the present invention, and FIG. 3 is a front metal gas meter of one embodiment of the present invention. 4 is a sectional view of the planetary gear device 36 and the cam device 20, FIG. 5 is a front view for explaining the structure and operation of the cam device 20, and FIG. 6 is a first cam. 61 is a front view, and FIG. 7 is a front view of the second cam 62. 20...Cam device, 21...Valve, 56...Follower, 6
1...First cam, 62...Second cam, 63, 66...Recess, 64...Forward movement direction, 65...Recess separation cam surface,
67... Recess fitting surface, 69... Arc cam surface, 71... Long hole, 72... Locking pin.

Claims (1)

[Claims] 1. A recess having a reciprocating angular displacement around the axis and recessed in the radial direction, a recess release cam surface is formed at the rear of the recess in the forward movement direction, and the recess release cam surface a first cam extending radially inward and forward in the outward movement direction forming a first angle β with the radial direction; It has a recess that is recessed inward in the direction, and a recess fitting surface is formed at the rear of the recess in the forward movement direction,
a second cam having an arcuate cam surface continuous in the circumferential direction from the radially outer end of the recess-fitting surface; and a follower to which a spring force is applied radially inward to the first cam and the second cam. The amount of mutual allowable angular displacement between the first cam and the second cam is such that when the first cam is at the forwardmost position in the forward movement direction relative to the second cam, the recess-fitting surface is detached from the recess. When the first cam is at the frontmost position in the backward movement direction relative to the second cam, the radially outer end of the recess-fitting surface is the first cam. Located in the recess of the cam, the first
The range is selected to be less than the maximum angular displacement of the cam, and the recessed recessed cam surface can be transferred to the arcuate cam surface when the follower is removed from the recessed area by the angular displacement of the first cam in the forward movement direction. The recess-fitting surface has a radial direction of the second cam and a second cam facing forward in the forward movement direction toward the radially inward side of the second cam.
extending at an angle γ, the second angle γ being selected to be less than or equal to the first angle β, further interposed in the middle of the gas flow path and interlocking with the follower;
a valve means that is in a closed state when the follower is fitted into the recesses of the first and second cams and is in an open state when the follower is on the arcuate cam surface of the second cam; The rotational power from the handle is transmitted to the first cam via the rotated handle and the input object, whereby the first cam is rotated in the forward movement direction, so that the follower is separated from the recessed recessed cam surface. gas flowing through the valve means, such that upon completion of rotation of the handle, the input material falls and the transmission of rotational power from the handle to the first cam is interrupted; and means for measuring the usage amount of the first cam and driving the first cam in the backward movement direction.