JPH0338124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a valve cap for a hollow tire, and in particular to a valve cap equipped with a display means for detecting and displaying a decrease in air pressure within the tire. It is related to.

BACKGROUND OF THE INVENTION A valve cap with a tire pressure drop indicator is disclosed in German Patent Application No. 26 27 529. The tire air pressure drop indicating means in this known valve cap is configured as an indicator consisting of a rotary disk fixed to a shaft that is engaged with a threaded portion of a hollow actuator through a laterally projecting pin. The actuator is axially moved by the diaphragm, and this movement rotates the protrusion of the rotary disk. A rotating ring having an indicator is adjustable on the outer periphery of the sleeve. When this known valve cap is attached to a valve tube, the air pressure of the tire acts on the air pressure chamber. As the air pressure in the air pressure chamber increases, the diaphragm expands and raises the actuator, thereby rotating the shaft. Rotate until the pressure in the shaft's pneumatic chamber and the spring pressure are balanced. In this state, the rotating ring is rotated to position the display section at the position of the protrusion of the rotating disk. From this state,
When the air pressure of the tire decreases, the actuator rotates the shaft and the rotary disk through an angle corresponding to the operating range of the actuator, thereby displacing the protruding portion of the rotary disk relative to the display portion of the rotary ring. Thus, the amount of decrease in tire air pressure is displayed based on the distance or angle between the protruding part of the rotary disk and the display part of the rotary ring.

This type of valve cap has a diameter of approximately 10 mm, and its length is approximately twice the diameter. Therefore, the space for accommodating the tire pressure display means is extremely small. On the other hand, a mechanism that converts linear motion in the axial direction into rotational motion requires high precision and is prone to malfunction.
In addition, the display section screwed onto the tire valve together with the rotating ring is extremely small, making it difficult to manually operate it and align the display section with the protrusion of the rotary disk. The amount of decrease in tire air pressure cannot be displayed unless the display unit is aligned with the protrusion of the rotary disk each time the air pressure of the tire is measured or adjusted.

West German Patent No. 396 474 shows means for preventing the return movement of a tire gauge. The indicator shown in this West German patent has a ratchet mechanism that allows movement of the indicator in the direction of protrusion while preventing movement in the direction of return. After the spring is activated and the indicator cannot be returned to its original position, the indicator must be returned to its initial position by removing the tire gauge from the valve tube.

Furthermore, German Patent Application No. 31 04 081 shows a tire gauge for tires. This tire gauge displays the actual air pressure based on the condition of the diaphragm.One end of the sleeve that is screwed onto the valve tube is hermetically sealed with a cup member made of a transparent material, and the air pressure of the diaphragm is measured through this transparent cup member. The structure is such that the deformation that occurs can be observed. Therefore, the tire air pressure is indicated by the degree of deformation of this diaphragm.

Problems to be Solved by the Invention The purpose of the present invention is to
To provide a valve cap having the same structure as the valve cap shown in 27 529, which has a simpler structure and higher reliability than the above valve cap, and which facilitates returning the display member to the initial position with respect to the indicator. This is what I am trying to do.

Another object of the present invention is to provide a valve cap that can ensure airtightness even in the event of failure of the diaphragm or piston or seal associated with the sleeve.

Means for Solving the Problems In order to achieve the above object, the present invention provides a sleeve that can be screwed onto a valve tube of a tire, and a sleeve that can be screwed onto a valve tube of a tire when the sleeve is in an operating state. an actuator for opening a valve provided; a pneumatic chamber that communicates with the inside of the tire when the valve is open and is isolated from the atmosphere by a diaphragm or piston; an indicator that operates in the direction of increasing and decreasing air pressure; a display member that operates in conjunction with the indicator; a return movement prevention means that restricts the axial movement of the display member in the direction of decreasing air pressure; and the indicator. and a spring that biases the display member in a decreasing direction opposite to the direction of driving by the pneumatic pressure in the pneumatic chamber, and the indicator is driven in the increasing direction as the pneumatic pressure in the pneumatic chamber increases, and at the same time the display member is moved in the increasing direction to set the display member to the set air pressure position, and as the air pressure in the air pressure chamber decreases, the return operation is regulated by the return operation regulating means independently of the display means. There is provided a tire valve cap with an air pressure display device, characterized in that the tire valve cap is moved in the direction and displays a decrease in tire air pressure from a set air pressure depending on its relative position with the display means.

Effects According to the present invention, when the valve cap according to the present invention is attached to the valve tube after adjusting the tire air pressure to a desired pressure, the indicator and the display member move linearly due to the air pressure inside the tire. It stops at the position corresponding to the air pressure. In this initial position, the display member remains fixed unless forced to return to the inoperative position. On the other hand, the indicator is linearly displaced in response to changes in air pressure, and therefore the tire air pressure is displayed based on the relative positional relationship between the indicator and the display member.

The structure of the present invention is described in the above-mentioned West German patent publication 26 27.
Considering the prior art disclosed in No. 529, the present invention does not require any operation conversion means, so the structure can be simplified compared to the prior art. If desired, the indicator member can be pushed down to return to the inactive position before installing the valve cap on the tire. Further, according to the present invention, there is no need to take any precautions, and the device can be simply attached to the valve tube of a tire, making it easy to use. While the valve cap is attached, the air pressure chamber formed in the sleeve is always in communication with the inside of the tire, so tire air pressure is always introduced into the air pressure chamber inside the valve cap. When the air pressure of the tire decreases, the indicator moves relative to the display member fixed at the initial position as described above to report the decrease in air pressure.

In particular, by using different colors for the indicator and the display member, or by coloring them in different colors, it is possible to further improve the visibility of the display indicating the decrease in air pressure.

Note that when the cap-shaped cover is fixed to the sleeve, in order to return the display member of the valve cap to the inoperative position, an impact is applied to the cap to release the frictional engagement between the display member and the return movement prevention means. Then, the display member returns to the inoperative position by its own weight.

Embodiment FIGS. 1 to 3 show essential parts of a first embodiment of a valve cap according to the present invention. This valve cap 10 includes a sleeve 12, a diaphragm 26, an indicator 40, and a spring 34.
, a display member 46, and a member 36 for preventing the return operation of the display member. As shown in FIG. 1, a partition wall 14 is formed in the sleeve 12 of the valve cap 10 at its longitudinally intermediate portion. A central hole 16 that expands upward is formed in the center of the partition wall 14 . A threaded portion is formed on the inner peripheral surface of the lower side of the sleeve 12, and this threaded portion is screwed into the valve tube 18 to lock the valve cap 10 to the valve tube. The sealing ring 20 is caulked to the sleeve between the upper end of the sleeve 12 and the upper end of the valve tube, and provides an airtight seal between the valve cap 10 and the sleeve. Sleeve 12 is valve tube 1
2 (operating state), the downwardly protruding portion 22 at the center of the partition presses the valve rod 24 of the valve tube 18 to hold the valve (not shown) in an open state, and the tire Air pressure (not shown) is configured to act on the air pressure chamber 30 through the central hole 16. In the illustrated first embodiment,
The above-mentioned pneumatic chamber 30 is defined by the diaphragm 26 and the partition wall. The peripheral edge of the diaphragm is hermetically pressed to the sleeve by a spring washer 28 within a groove formed in the inner peripheral surface of the sleeve 12.

Although the above example uses the diaphragm 26, this diaphragm can be replaced by a piston that fits into the sleeve and moves in the axial direction of the sleeve. At this time, a groove is provided on the outer circumferential surface of the piston, and an O-ring is housed in the groove to airtightly seal between the inner circumferential surface of the sleeve and the outer circumference of the piston, thereby blocking air pressure from the atmosphere.

As mentioned above, the air pressure chamber 30 communicates with the inside of the tire through the intermediate hole 16 and the valve tube 18 while the valve rod 24 is pressed.
It is configured such that an air pressure equal to the air pressure of the tire acts on the air pressure chamber 30.

A disk portion 32 is formed at the lower end of the shaft-shaped indicator 40 and comes into contact with the upper end of the diaphragm 26 . This disk portion 32 functions as a spring seat for a coil spring 34. The other end of the spring 34 is seated in a ring member 36. The ring member 36 functions as a spring seat having sufficient rigidity for the spring 34, but is elastically deformable, and the sleeve 12
Its peripheral edge is fitted into a fitting groove 38 formed on the inner circumferential surface near the upper end. The shaft portion functioning as the indicator 40 projects upward from the disk portion 32 and is inserted into the through hole 4 formed in the ring member 36.
2 with a gap between it and the inner circumferential surface thereof.

The shaft portion functioning as the indicator 40 is formed with a slot 44 extending in the axial direction thereof. This slot 44 is formed so that its lower end is located substantially on the same plane as the upper surface of the disk portion 32. In this slot 44 there is a display member 46.
is accommodated. The display member 46 is spaced apart from the inner surface of the slot and is movable axially along the slot independently of the axial movement of the shaft. The length of the display member 46 corresponds to the length of the slot 44, and is set to several times the width. On the other hand, the width of the display member 46 is set to several times the thickness. The width of this display member 46 is slightly larger than the diameter of the shaft portion that acts as the indicator 40, and as shown in FIG. It is designed to stand out. Furthermore, the width of the display member 46 is slightly larger than the inner diameter of the through hole 42 formed in the ring member 36, and the opposing portion 48 of the inner peripheral surface of the through hole 42 is formed by both side edges of the display member 46. , 50 are pressed outward to elastically deform, and are frictionally engaged by the elastic return force of the ring member.

When the valve cap 10 is attached to the valve tube 18, tire air pressure is introduced into the air pressure chamber 30. As a result, the diaphragm 26 is displaced and pushes the indicator 40 upward until it balances the downward pushing force of the spring 34, causing the upper portion of the indicator 40 to protrude from the sleeve.
For this reason, the spring 34 used in the valve cap of this embodiment is set at a pressure corresponding to 1.5 to 3 bar, corresponding to the tire pressure of a typical vehicle. When the valve cap of the present invention is used for a bicycle, the above spring pressure is 4
The pressure corresponds to atmospheric pressure, and the spring pressure is set higher than that for automobiles. Furthermore, by adjusting the positional relationship between the diaphragm and the spring, the valve cap of the above embodiment can also be used for truck tires.

As mentioned above, the tire pressure chamber 30
In response to the air pressure, the indicator 40 projects upwardly from the sleeve 12 and is located at a position where the upward force exerted on the diaphragm 26 by the air pressure and the downward spring pressure of the spring 34 collide. As the indicator 40 moves upward, the display member 46 also moves upward and is positioned at an initial position corresponding to the tire air pressure. In particular, the lower end of the display member 46 is in contact with the bottom of the slot 44, and is pushed upward by the upward movement of the indicator 40 and set to the initial position corresponding to the initial tire pressure. Thus, it is not necessary to manually set the initial position of the display member. As described above, the display member 46 is frictionally engaged with the inner circumferential surface of the through hole 42 of the ring member 36 at its both side edges, and its movement in the axial direction is restricted. This is set to be smaller than the upward biasing force of the diaphragm caused by the air pressure of the tire, so that when the indicator 40 rises due to the air pressure of the tire, the display member 46 can move upward together with the indicator 40. Since the display member 46 is moved to the initial position with its lower end in contact with the bottom of the slot 44 of the indicator 40, when it is set to the initial position,
The position completely matches the position of the indicator 40, and the initial setting accuracy is extremely high.

When the air pressure of the tire decreases, the pressure in the air pressure chamber 30 decreases accordingly, and the diaphragm 26
The upward pressing force applied to is reduced. As a result, the upward pressing force due to air pressure and the spring 34
The balance of the downward spring pressure due to
The indicator 40 descends toward the sleeve 12 until it reaches a position where the air pressure and spring pressure are balanced. At this time, the display member 46 is prevented from descending due to frictional engagement with the circumferential surface of the through hole 42 of the ring member 36, and is held at the initial position corresponding to the initial air pressure of the tire. Therefore, the display member 46 having a length corresponding to the downward movement of the indicator 40 is exposed from the upper end of the indicator. At this time, if the indicator 40 and the display member 46 are colored in different colors, the decrease in tire air pressure can be easily recognized even from a distant position. Indicator 40 when tire pressure drops
The positional relationship between the display member and the display member is as illustrated in FIG.

If the tire pressure drops, the valve cap 10 is removed and the tire is refilled with air in a known manner to adjust the tire pressure to the desired pressure.
When removing the valve cap 10 from the tire, push down the display member 46 and insert its lower end into the slot 4.
Keep it in contact with the bottom of 4. After adjusting the tire air pressure to the desired pressure, the valve cap 10 is reattached to the valve cap. Then, the tire valve is opened and the tire air pressure reaches the air pressure chamber 30.
, the diaphragm 26 is displaced again,
The indicator 40 and display member 46 are raised to the initial position corresponding to the tire air pressure. The length of indicator member 46 is equal to the length of slot 44 of the indicator, so that the lower end of indicator member 46 is in slot 4.
4, the display member is not exposed from the indicator. Therefore, as long as the display member 46 is hidden within the indicator 40, it can be determined that the tire air pressure is normal.

In addition, in the illustrated embodiment, the diaphragm 2
6 is in close contact with the sleeve 12 in a completely airtight state by the spring washer 28, but in the event that the seal becomes incomplete or the diaphragm is damaged, the downward facing The hemispherical protrusion 40' is pressed downwardly by the spring 34 and fits together with the diaphragm 26 into the enlarged upper end of the central hole 16, thereby preventing the tire from being completely deflated. Since the movement of the diaphragm is carried out slowly, the load applied to the diaphragm is small and the risk of it being damaged is extremely low. Further, when the diaphragm is damaged, the damage often occurs at or near the clamped portion of the periphery, and an emergency seal can be ensured by the central portion.

According to the above embodiment, when the valve cap according to the present invention is attached to the valve tube after adjusting the tire air pressure to a desired pressure, the indicator and the display member move linearly due to the air pressure inside the tire. It stops at the position corresponding to the air pressure. In this initial position, the display member remains fixed unless forced to return to the inoperative position. On the other hand, the indicator is linearly displaced in response to changes in air pressure, and therefore the tire air pressure is displayed based on the relative positional relationship between the indicator and the display member.

In particular, by using different colors for the indicator and the display member, or by coloring them in different colors, it is possible to further improve the visibility of the display indicating the decrease in air pressure.

Furthermore, in the above embodiment, a pin may be provided in the sleeve in place of the downward bulging portion 22 that functions as an actuator member, and the sleeve can be attached to the valve tube in the same manner as above. Then, a pin is arranged to open the valve. In this case, for example, a lever may be provided that is connected to the pin at one end and protrudes from the sleeve at the other end, and by operating this lever, the pin can be operated to open the valve. Therefore, if the lever is operated to control the opening and closing of the valve via the pin, the air pressure chamber will communicate with the inside of the tire only while the lever is held in the valve open position.

4 to 8 show a modification of the above embodiment, in which a hat-shaped or cup-shaped cover made of a transparent member is fitted to the end of the sleeve on the side far from the valve, and the indicator is The display member is exposed through the cover, and the end of the sleeve is hermetically closed. According to this configuration,
For example, even if the diaphragm or piston is damaged or its sealing performance deteriorates and it becomes impossible to maintain airtightness, an airtight seal can be maintained and there is no risk of air leakage. .

FIG. 4 shows a second embodiment of the valve cap of the present invention. In this second embodiment, the construction of the main parts of the present invention, such as the sleeve, diaphragm, and indicator, is the same as in the first embodiment. In this second embodiment, the end of the sleeve 12 on the side farther from the valve tube 18 is hermetically closed with a cap-shaped cover 52. This cap-shaped cover 52 is made of a colorless and transparent material such as well-known polyacrylate. As shown in the figure, the cover 52 is engaged with the outer periphery of the upper end of the sleeve 12, and has an indicator 4 between it and the sleeve.
0 and a space from which the display member 46 protrudes. Maintaining airtightness between the cover 52 and the sleeve 12 can be achieved by various well-known methods. That is, for example, the inner diameter of the cylindrical portion 54 of the cover 52 is
By making the diameter slightly smaller than the outer diameter of the upper part of the cover 2, these engagements are performed while elastically deforming the cylindrical part of the cover, and airtightness can be maintained by the elastic return force of the cover. It is also possible to add a seal holding member. Preferably, the cover 52 is threaded onto the sleeve 12, as shown at 53. In this case, the cover 52 is disengaged from the sleeve and removed, if necessary, when the display means is pushed from the initial setting position to the inactive position. Furthermore, a sealing ring 51 is inserted between the opposite ends of the covered sleeve to further ensure an airtight seal. Furthermore, if necessary, it is also possible to hermetically weld or hermetically bond the cover and the sleeve.

In addition, when the cap-shaped cover is fixed to the sleeve by airtight welding, in order to return the display member of the valve cap to the inoperative position, an impact is applied to the cap to reduce the friction between the display member and the return movement preventing means. Once the connection is released, the display member will return to its inoperative position under its own weight.

FIG. 5 shows the third valve cap according to the invention.
An example is shown. In this embodiment, the cylindrical portion 54 of the cap-shaped cover 52 is hermetically engaged with the inner surface of the upper side of the sleeve 12. In order to improve airtightness, welding such as ultrasonic welding is performed, for example. An annular groove 3 is formed on the inner surface of the cylindrical portion 54.
A ring member 3 is formed in this groove.
The peripheral edges of No. 6 fit together. An inward protrusion 55 is formed below the groove 39 to protrude from the inner surface of the cylindrical portion. This inward protrusion 55 acts as a spring seat for the spring 34.

Thus, the ring member 36 is not loaded with spring pressure. As a result, the operation of the indicator 40 can be guided and the initial position of the display member can be maintained more reliably.

In this embodiment, the cap-shaped cover 52 is formed by integrally forming a cylindrical portion 54 and a top portion 56.
6 has a shape that expands downward. In addition,
As in the previous embodiment, the cover 52 is entirely colorless;
It is made of transparent material.

According to the above embodiment, the cover that covers the upper end of the sleeve is formed in a substantially truncated conical shape, and slightly widens from the top toward the cylindrical portion below. The display member is provided with a protrusion that protrudes from the indicator, and as the indicator moves upward, the display member is frictionally engaged with the inner circumferential surface of the cover to fix the display member at the initial position. According to this example, since the cover has the functions of both maintaining airtightness and functioning as a display member, there is no need to provide a separate return operation blocking member.

FIGS. 6 and 7 show a valve cap according to a fourth embodiment of the present invention, and the cap-like cover is formed entirely in the shape of a hollow truncated cone. A base portion 59 that bulges out laterally is formed at the lower end of the side wall of the cover 52, and this base portion 59 is elastically engaged with an annular groove 39 formed on the inner wall surface of the sleeve 12. The outer diameter of the base portion 59 of the cover 52 is
The inner diameter of the sleeve 12 is larger than the inner diameter of the sleeve 12, and when the cover is fitted into the sleeve, the side wall portion of the cover is elastically deformed inward to fit the base portion into the annular groove, and the side wall portion and An airtight seal is formed by the return force of the base. If necessary, sleeve 1
2 and the base portion 59 can also be hermetically welded.
On the other hand, the lower portion of the base portion acts as a spring seat for the spring 34. The inner edge 61 of the base also acts as a guide for the indicator 40 and the display member 46.

According to this embodiment, the inner wall surface of the cover 56 is
It functions as means for preventing the return operation of the display member. In this embodiment as well, the indicator member 46 is comprised of a small plate that runs along the slot 44 of the indicator 40 and is generally rectangular in shape. In this embodiment, as shown in FIG.
A protrusion 62 that protrudes laterally at the upper end of the display member,
63 to form a substantially T-shape.

The side edges of the protrusions 62 and 63 are inclined in accordance with the inclination of the inner wall surface of the cover 56, and when the indicator 40 and the display member 46 move upward due to tire air pressure, the protrusions 62 and 63 are inclined. , 63 come into contact with the inner wall surface 64 of the cover 56 and are held at the initial position by the frictional force with the inner wall surface.

Figure 6 shows the valve cap removed from the tire, and the diaphragm 26
is in contact with the partition wall 14. In this state, the upper end of the display member 46 is located on the same plane as the upper end of the indicator 40, and the upper surfaces of the display member and the indicator are located on the same plane as the upper end surface of the sleeve 12. It is composed of When this is fitted into the valve tube of the tire, the valve is opened as described above, and the inside of the tire and the pneumatic chamber 30 are brought into communication with each other, so that the pneumatic pressure inside the tire is loaded onto the pneumatic pressure chamber. As a result, the diaphragm 26 is deformed to expand the air pressure chamber, and the indicator 40 is moved upward together with the display member 46. At this time, the lower end of the display member 46 is connected to the indicator 40.
and moves upward together with the indicator to an initial position corresponding to the initial air pressure of the tire. At this time, the protrusions 62 and 63 of the display member
comes into contact with the inner surface of the side wall of the cover 56 and rises to the above-mentioned initial position while elastically deforming it. Therefore, the protrusions 62 and 63 of the display member 46
is frictionally engaged with the cover side wall due to its elastic force to hold the display member in the initial position. When the tire air pressure decreases, the indicator 40 is lowered by the biasing force of the spring 34 to a position where the biasing force and the pressure in the air pressure chamber are balanced. At this time, the display member 46 is held in a state where its protrusions 62 and 63 are frictionally engaged with the inner surface of the side wall of the cover 56, so that the display member is held at the initial position.
If the entire indicator is made of black plastic, for example, the display member 46
is made of a black material, and its side edges and the side edges of the protrusion are colored white. In this way,
By moving the indicator 40 downward, this white side edge is exposed, and even if the thickness of the display member is a fraction of a millimeter, this white portion can be penetrated through the cover.

Further, even if the display member is made red and the indicator is made green, good visibility can be obtained.

FIG. 8 shows a valve cap according to a fifth embodiment of the present invention, and in this figure, each element constituting the valve cap is shown in an exploded manner.

A threaded portion 71 is formed on the inner peripheral surface of the lower side of the sleeve 70 . This threaded portion 71 engages with the valve of the tire and fixes the valve cap to the valve. With the valve cap attached to the valve, the actuator member 73, which projects downward from the partition wall 72, presses the valve rod into the valve tube to open the valve. When the valve is opened, the air pressure chamber 75 communicates with the inside of the tire through the through hole 74 provided in the partition wall adjacent to the actuator member 73, and the air pressure inside the tire is introduced into the air pressure chamber.

Similar to the previous embodiment, the pneumatic chamber in this embodiment is defined between bulkhead 72 and diaphragm 76. The diaphragm 76 is formed in a circular shape,
A bead portion 77 is provided at its peripheral edge.
When the valve cap is assembled, this bead material 77 is pressed and deformed by the cylindrical lower edge of the cap-shaped cover 80 to form an airtight seal between the lower end of the cylindrical portion 82 and the partition wall 72. do. Above the partition wall 72, a stepped portion 79 is formed on the inner circumferential surface of the sleeve 70 for positioning a hat-shaped cover.

The sleeve 70 is made by injection molding.
It is made of a strong, impact-resistant resin such as high-density polyester.

The cap-shaped cover 80 integrally includes the cylindrical portion 82 and the top portion 84, and the entire cover is made of colorless and transparent material such as well-known polyacrylate. A step portion 85 protruding from the inner circumferential surface of the cylindrical portion is formed at the joint between the top portion 84 and the cylindrical portion 82 . The side wall portion 86 of the top portion 84 functions as a guide for the shaft portion 92 of the indicator 90.

The upper end of the spring 89 is seated on the lower end surface 87 of the stepped portion 85, and therefore, the lower end surface 87 functions as a spring seat for the spring 89. A jaw 88 that protrudes laterally is formed on the outer circumferential surface of the cylindrical portion 82, and this jaw 88 comes into contact with the stepped portion 79 of the sleeve 70 when the cover 80 is inserted into the sleeve 70. . After all elements are assembled, the overlapping portions of the sleeve 70 and cover are joined by ultrasonic welding.

The indicator 90 consists of a shaft portion 92 and a disc-shaped portion 93, and the disc-shaped portion 93 is integrally provided at the lower end of the shaft portion 92. The upper surface of the disc-shaped portion 93 functions as a spring seat on which the lower end of the spring is seated. A slot 95 extending in the axial direction is formed in the center of the shaft. A protrusion 96 protrudes from one side wall of the slot 95 and extends toward the other wall. Instead of the protrusion 96, a pin may be provided between both walls of the slot 95, with both ends of the pin engaging in a blind hole formed in the wall.

The width of the slot 95 is set so that the display member 100, which is made up of a small plate, can be operated within the slot. In the assembled state, the lower end of the display member 100 is in contact with the bottom 97 of the slot 95. When tire air pressure is introduced into the air pressure chamber, the display member 100 moves upward in the axial direction toward the hat-shaped cover 80 together with the indicator 90.

The display member 100 is composed of a substantially rectangular small plate as described above. The upper end of the display member 100 is provided with protrusions 104 and 105 that project slightly laterally from the longitudinal side edges 106, and these protrusions 104 and 105 are arranged at the top when the display member is moved to the initial position. The display member is frictionally engaged with the inner circumferential surface of the side wall 84 to hold the display member at the initial position. However,
Even if the tire air pressure drops, the air pressure in the air pressure chamber 75 drops, and the indicator 90 moves down due to the biasing force of the spring 89, the display member remains at the initial position, as previously explained with reference to FIG. is maintained. Note that a long hole 107 is formed in the display member 100, and the display member 1 is inserted into this long hole 107.
00 into the slot 95, the protrusion 96 engages.

The length of the cylindrical part is preferably such that when the cylindrical part is fitted into the sleeve, the lower end thereof crosses the bead formed on the periphery of the diaphragm forming the pneumatic chamber at right angles to the axis of the sleeve. An airtight seal is formed by pressing against the inwardly bulging portion formed on the partition wall or the inner wall surface of the sleeve. At this time, since the cover also functions as a retainer for the diaphragm, no extra member is required to hold the diaphragm, and the number of parts can therefore be reduced.

Moreover, if configured as described above, the display member can
A protrusion or protrusion 9 that is provided on the indicator by forming a long hole or long groove 107 extending in the longitudinal direction.
6, so that when the relative movement of the indicator with respect to the display member exceeds a predetermined amount, the protrusion or protrusion abuts the end of the elongated hole or slot to operate the display member. It consists of That is,
When the air pressure in the air pressure chamber is completely relieved, the indicator moves downward beyond the predetermined amount by the biasing force of the return spring, and as a result, the display member moves beyond the predetermined amount of the indicator. The return operation will be performed downward by the amount of time. For this reason, the length of the elongated hole or elongated groove is such that when the tire air pressure decreases, the indicator can move downward without affecting the display member, and the air pressure in the air pressure chamber is almost completely relieved. At times, the display member is selected to be activated by the indicator. If necessary, it is also possible to change the arrangement of the elongated holes or elongated grooves and the projections or protrusions. That is, it is also possible to provide a protrusion or projection on the display member, and to form a long hole or groove on the indicator.

Preferably, the spring 89 is constituted by a coil spring, with an appropriate gap between the spring 89 and the inner peripheral surface of the cylindrical portion 82 of the cover 80, and with an appropriate gap between the shaft portion 92 of the indicator 90 and the inner circumferential surface of the cylindrical portion 82 of the cover 80. Configure it so that it surrounds it. In the inventors' experiments, when the air pressure in the diaphragm, spring, and 0.1 bar air pressure chamber decreased, the indicator 90 was approximately 0.05 bar.
mm to 0.20 mm lowering was selected.

FIG. 9 shows a modification of the first embodiment of the invention shown in FIGS. 1-3. According to this modification, the diaphragm 26 in the first embodiment is
has been replaced by Viston 27. The outer diameter of the piston 27 is configured to approximately match the inner diameter of the corresponding portion of the sleeve 12, and furthermore, an annular groove is formed on the outer peripheral surface of the piston 27, and an O-ring is fitted into this annular groove. This O-ring ensures the airtightness of the sleeve. This piston 27 defines a pneumatic chamber 30 together with the partition wall 14 . Similar to the first embodiment described above, this air pressure chamber 30 communicates with the interior of the tire to introduce air pressure within the tire while the valve cap is attached to the valve tube. As the pressure in the air pressure chamber 30 increases, the piston 27 moves upward against the spring pressure of the return spring 34 applied to the indicator whose lower surface is in contact with the piston surface. Along with this, the indicator 40 moves upward together with the display member 46 constituted by a small plate, and is located at an initial position corresponding to the tire air pressure when the valve cap is installed. Similar to the first embodiment above, the display member 46
is fixed at the initial position by frictionally engaging with the peripheral edge of the through hole of the ring member at the side edge.

The piston 27 moves downward in response to a decrease in the pressure in the pneumatic chamber due to a decrease in tire pneumatic pressure, and moves to a position where the spring pressure of the return spring 34 and the pressure in the pneumatic chamber 30 are balanced. At this time, in order to enable the piston to reciprocate in response to pressure changes in the pneumatic chamber, the frictional force between the O-ring and the piston's outer peripheral surface and the sleeve's inner peripheral surface is controlled by the air pressure introduced into the pneumatic chamber and the spring pressure of the return spring. is set sufficiently small. It should be noted that, if desired, the piston and/or the sleeve can be provided with other known sealing means to further ensure the hermetic sealing of the sleeve. this is,
For example, as shown in phantom lines, a hat-shaped cover 53 similar to that shown in the second embodiment is attached to the sleeve 1.
This can be achieved by installing 2. Furthermore, if necessary, a protrusion 31 having a size and shape corresponding to the shape of the tapered part 15 above the central hole of the partition wall 14 is made to protrude from the lower surface of the piston, thereby causing a problem in the airtight seal of the sleeve and causing air leakage. Even in this case, air pressure corresponding to the spring pressure of the return spring may be ensured within the tire.

In this case, the cap-shaped cover is made of a colorless and transparent material, as in the second embodiment.

Further, in the above example, the piston 27 is formed separately from the indicator 40, but it is also possible to form them integrally. Furthermore, if the above-mentioned protrusion 31 is made of an elastically deformable material such as rubber and is attached to the lower surface of the piston, the sealing performance in the event of air leakage can be further improved. I can do it.

Effects of the Invention According to the valve cap of the present invention,
It is possible to visually display the decrease in tire air pressure. The method of using the valve cap of the present invention is as follows:
It is very simple, and all you have to do is simply attach the valve cap to the tire's valve tube. At this time, the indicator and the display member are automatically set to the initial position corresponding to the initial air pressure of the tire. This valve cap has a very simple construction, so it is very reliable and can be used even in bad weather or for 200
Long-term tests have confirmed that it can be used safely even when driving at high speeds of Km/h or higher. This valve cap meets DIN7780 regulations. Furthermore, since the valve cap according to the present invention has a simple structure and a small number of parts, it can be mass-produced and its production cost is very low.

Although the present invention has been described above with respect to various embodiments, the present invention is not limited to these embodiments, but includes any changes, modifications, and implementations in different ways that include the gist of the present invention. It is.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the valve cap according to the first embodiment of the present invention in an operating state, and FIG. 2 is a sectional view similar to FIG. The figures are a sectional view taken along line 3-3 in FIG. 1, FIG. 4 a sectional view of a valve cap according to a second embodiment of the present invention, and FIG. 6 is a sectional view of a valve cap according to a fourth embodiment of the present invention, and FIG.
The figure is an explanatory view showing a state in which the display member used in the valve cap shown in FIG. 6 is engaged with the hat-shaped cover, and FIG. 8 is an exploded cross-sectional view showing the valve cap according to the fifth embodiment of the present invention. FIG. 9 is a modification of the first embodiment shown in FIG. 10...Valve cap, 12...Sleeve,
14... Partition wall, 16... Central hole, 18... Valve tube, 20... Sealing ring, 22...
Bulging portion, 24...Valve rod, 26...Diaphragm, 30...Pneumatic chamber, 32...Disk portion, 34...Spring, 36...Ring member,
44...Slot, 46...Display member, 56...
cover.

Claims (1)

[Claims] 1. A sleeve that can be screwed onto the valve tube of a tire, and when the sleeve is in an operating state,
an actuator that opens a valve provided in a valve tube; a pneumatic chamber that communicates with the inside of the tire when the valve is open and is shut off from the atmosphere by a diaphragm or piston; and a pneumatic chamber that is driven by the diaphragm or piston. an indicator that operates in the direction of increasing and decreasing air pressure in the axial direction; a display member that operates in conjunction with the indicator; and a return movement prevention means that restricts the axial movement of the display member in the direction of decreasing air pressure; and a spring that biases the indicator in a decreasing direction opposite to the direction in which the air pressure in the pneumatic chamber is driven, and the indicator is simultaneously driven in an increasing direction as the air pressure in the pneumatic chamber increases. Independently of the display means, the display member is moved in an increasing direction to set the display member at a set air pressure position, and the return operation is regulated by the return operation regulation means as the air pressure in the air pressure chamber decreases. 1. A tire valve cap with an air pressure display device, characterized in that the tire valve cap is configured to display a reduction in tire air pressure from a set air pressure depending on a relative position with respect to the display means.