JP2872081B2 - Tire valve cap and air pressure measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire valve cap which is mounted on a tire valve and measures tire pressure.

[0002]

2. Description of the Related Art Conventional tire valve caps include:
For example, as shown in FIG. 17, there is one described in Japanese Patent Application No. 6-138529 filed by the present applicant. In FIG. 17, reference numeral 1 denotes a tire valve cap. The tire valve cap 1 has a body 3 having a window 2 formed therein and a body 3 fixed to the inside of the body 3 and moving integrally with the body 3. It has a center piece 4 as an opening / closing member that opens the valve to introduce air pressure and closes the valve when not moving, and a display unit 5 that moves by air pressure introduced from the center piece 4 to display tire pressure. It has a pressure indicating piston 6 as a moving member.

According to the tire valve cap 1, the body 3 is pushed, the valve of the tire tube is opened by the center piece 4 which is fixed inside the body 3 and moves integrally with the body 3, and air pressure is introduced. The tire pressure is displayed by the pressure display piston 6 which is moved by the introduced air pressure. That is, the tire valve cap 1 has a tire pressure indicator, and when the body 3 is pressed, the tire pressure is displayed in a color, for example. For example, red indicates low pressure indicating the need for supply pressure, yellow indicates tire pressure is sufficient for normal running, and blue indicates tire pressure for high speed running.

[0004]

However, in such a conventional tire valve cap, when air is introduced into the head of the piston for measurement, in a normal state, the piston is moved to the position of the tire. Depending on the air pressure, the piston moves to the position corresponding to the sum of the air pressure contained in the chamber behind the piston and the force generated by the deflection of the pressure spring, but the same operation is performed after leaving the measurement for a long time. However, the O-ring is momentarily stuck to the inner surface of the center piece, and often does not move only by air pressure. This is because the grease applied to the surface of the O-ring and the center piece is pressed for a long time, and the pressed portion is microscopically cut off in the oil film, and the sliding resistance is higher than the state with grease It is thought to be. In this state, if you move the O-ring with a little force other than air pressure,
The tire pressure can be measured smoothly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and uses a force for pressing an upper cover during measurement to move a moving member and slightly move an O-ring. It is an object of the present invention to provide a tire valve cap capable of measuring smoothly with a tire.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an upper cover, a rotatable unit integrally provided with the upper cover, and opening of a valve of a tire tube by moving in an axial direction. An opening / closing member that closes the valve when air pressure is introduced and not moving, and a moving member that is housed in the opening / closing member and moves by air pressure introduced from the opening / closing member, and pushes the opening / closing member for measuring tire pressure. Then, before the opening / closing member hits the projection of the anchor nut member that supports the opening / closing member via the elastic member, the opening / closing member has a sleeve that slightly moves the moving member by hitting the base end of the anchor nut member.

Further, in the present invention, the length of the sleeve is made larger than the sum of the length of the projection of the anchor nut member and the thickness of the step portion of the opening / closing member abutting on the projection. The sleeve of the present invention has a pair of two parts, and the two parts are inserted into a substantially semicircular hole provided in the small cylindrical part of the opening / closing member. Further, the present invention has an outer cylinder inserted into a body, a pressure indicating rod housed in the outer cylinder, having a seal portion at an end thereof and moving by air pressure, and an air hole movably housed in the body. And a projection for slightly moving the seal portion.

[0008]

According to the tire valve cap of the present invention having such a configuration, when the opening / closing member is pushed in for measuring tire pressure, the opening / closing member supports the projection of the anchor nut member which supports the opening / closing member via the elastic member. Since the sleeve contacts the base end of the anchor nut member slightly before moving, the O-ring does not stick to the inner wall of the opening / closing member, and the tire pressure can be measured smoothly.

Further, since the length of the sleeve is made larger than the sum of the length of the projection of the anchor nut member and the thickness of the step portion of the opening / closing member abutting on the projection, the force for pressing the upper cover when measuring the tire pressure is used. To move the moving member,
The O-ring can be moved slightly. In addition, the sleeve has a pair of two parts, and the two parts are inserted into a substantially semicircular hole provided in the small cylindrical part of the opening / closing member, so that the sleeve does not fall out of the opening / closing member.

Further, the pneumatic pressure measuring device of the present invention has an outer cylinder inserted into a body, a pressure indicator rod housed in the outer cylinder, having a seal portion at an end thereof, and movable by air pressure, and movable in the body. Is provided with a projection for slightly moving the seal portion, so that even with a normal rod-shaped air pressure measuring device, the tire pressure can be smoothly measured by the projection pressing the seal portion.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the present invention. The left half of FIG. 1 shows a state of being attached to a tire valve,
The right half of FIG. 1 shows a state in which the head is pushed to check the tire pressure and the tire air pressure enters inside.

In FIG. 1, reference numeral 11 denotes a lower cover,
The lower cover 11 is fitted to an anchor nut 12 as an anchor nut member. That is, a spline 12A is formed on the outer periphery of the anchor nut 12, and the spline formed on the inner wall of the lower cover 11 is fitted to the spline 12A. This is to prevent the tire valve cap 13 from slipping inside the anchor nut 12 even when the lower cover 11 is turned when the tire valve cap 13 is attached to or detached from the tire. A protrusion 11A is formed at the lower end of the inner wall of the lower cover 11, and the protrusion 11A prevents the lower cover 11 from coming off when the lower cover 11 is pressed into the anchor nut 12. A serration 11B is formed on the outer periphery of the lower cover 11, and the serration 11B is provided to prevent slippage.

An upper cover 14 made of a transparent material is accommodated in the lower cover 11 so as to be slidable in the axial direction, and a cylinder 15 as an opening / closing member maintains airtightness in the upper cover 14. It is press-fitted so that it can be used.
When the upper cover 14 is pushed downward, the cylinder 15 slides downward integrally with the upper cover 14. A step portion 15A is formed on the outer periphery of the cylinder 15, and a return spring 16 is interposed between the step portion 15A and a concave portion 12B formed above the anchor nut 12. The cylinder 15 is integrated with the upper cover 14 and the return spring 1
When the other stepped portion 15B formed on the outer periphery of the cylinder 15 hits the end face 12D of the projection 12C formed on the upper portion of the anchor nut 12 when sliding downward against the cylinder 6, the cylinder 15 stops sliding downward. I do. A small cylindrical portion 15C is formed in the cylinder 15, and an O-ring 17 is interposed on the outer periphery of the small cylindrical portion 15C.
When the tire pressure is measured, it functions as a seal with the projection 12C of the anchor nut 12.

At this time, the space 18 is divided into two spaces 18A and 18B by the O-ring 17, the reaction force in the space 18A becomes the same high pressure as the tire pressure, and the air in the space 18B is separated from the lower cover 11 and the upper It exits through a gap 19 between the covers 14, a space 20 between the lower cover 11 and the upper cover 14, and a gap 21 between the lower cover 11 and the upper cover 14.

Reference numeral 22 denotes a sleeve. The sleeve 22 is loosely fitted to the small cylindrical portion 15C of the cylinder 15. The sleeve 22 has a sleeve body 22A and a pair of two parts 22B protruding downward from the sleeve body 22A. The two portions 22B have bent portions 22C whose ends are bent outward, and the outer diameter thereof is larger than the small cylindrical portion 15C of the cylinder 15, and the assembling surface 15D inside the small cylindrical portion 15C of the cylinder 15 is assembled. It is press-fitted by applying a force that shrinks the pair of two parts 22B by utilizing. Once the sleeve 22 is pressed into the small cylindrical portion 15C of the cylinder 15, the outer diameter of the sleeve body 22A is
Since it is larger than the small cylindrical portion 15C of No. 5, it can move in the axial direction, but does not fall out of the small cylindrical portion 15C.

Here, the length of the sleeve 22 is indicated by a, and the length a is set to be larger than the sum b of the length of the projection 12C of the anchor nut 12 and the thickness of the step 15B of the cylinder 15. I have. Therefore, the step 15B of the cylinder 15 is connected to the end surface 12 of the projection 12C of the anchor nut 12.
The sleeve 22 hits the base end 12E of the anchor nut 12 before hitting D. For this reason, the piston 23 as a moving member moves slightly upward, and the O-ring 24 also moves slightly upward. That is, the piston 23 is slightly moved by using the force pressing the upper cover 14 when measuring the tire pressure.

15G is a small cylindrical portion 15C of the cylinder 15.
The push rod 15G is formed integrally with the center hole 1 formed in the anchor nut 12.
When pushing the valve shaft of the tire (not shown) through 2F,
The tire valve opens. When the tire valve is opened, the air pressure is increased from the center hole 12F to the sleeve 22 and the cylinder 1
5 is introduced into the pneumatic chamber 25 formed between the slanted surface 15D and the head 23A of the piston 23. Further, a hole (not shown) formed at the center of the sleeve body 22A of the sleeve 22 acts on the head 23A of the piston 23.

A piston 23 is slidably housed in the cylinder 15, and when air pressure acts on the head 23A of the piston 23, the piston 23
Slide up against 6. The pressure spring 26 is provided for the disc 2 placed inside the upper cover 14.
7 and interposed between the inner wall of the step 23B of the piston 23,
A preset load is applied so that the tire pressure becomes the minimum pressure at the time of measurement.

On the outer periphery of the piston 23, the O-ring 24
The O-ring 24 seals the air pressure of the pneumatic chamber 25 from entering the sealed chamber 28 formed between the piston 23 and the upper cover 14. The diameter of the chamber 28 is formed larger than the diameter of the piston 23. Therefore, the capacity of the chamber 28 for receiving the air pressure confined by the movement of the piston 23 becomes large,
The rise in air pressure can also be kept low by the movement of. When air pressure is introduced into the air pressure chamber 25, the piston 23 moves the air pressure in the chamber 28 and the pressure spring 2.
6 to a position that balances the total value of the spring forces. At the end of the piston 23, a lug 23C is formed as a pressure indicating portion for displaying pressure. It is colored. On the other hand, the extending portion 15 formed to extend from the end of the cylinder 15
E is colored with an inconspicuous color such as black. In this manner, the ear 23C and the like and the extension 15E of the cylinder 15 are color-coded. The extension 15E has a display 15F.
Are provided, and a scale including a line indicating the pressure value and a numerical value indicating the pressure value are displayed on the display unit 15F by printing.
A slit portion described later is formed between the extending portions 15E,
The ear 23C fits into the slit.
Therefore, since the display section 15F and the ear section 23C have the same cylindrical surface, there is no error due to the viewing angle. Like a normal thermometer, since the ear 23C moves to indicate the pressure in a bar shape, it is easier to read than a scale or numerical value that moves.

Further, since the cylinder 15 integral with the upper cover 14 is rotatably supported in the lower cover 11 by the anchor nut 12 via the return spring 16, the display portion 15F and the ear portion 23C can freely rotate. , And can be easily viewed. Anchor nut 1
A screw 12G is formed inside 2, and a valve cap portion of a tire (not shown) is screwed into the screw 12G. The valve base is attached to an air port of a tube (not shown), and a valve head (not shown) is screwed into the valve base. A hole is formed in the center of the valve head, and a shaft (not shown) supporting the valve of the tire passes through the hole. When the push rod 15G is not pushed as shown in the left half of FIG. 1, the valve of the tire is closed, and the air pressure is not supplied to the air pressure chamber 25.
As shown in the right half of FIG. 1, when the push rod 15G is pushed downward, the valve is opened, and the air pressure in the tube is supplied to the air pressure chamber 25 through the center hole 12F.

Next, FIGS. 2 to 7 show the cylinder 15. 2 is a half sectional view of the cylinder 15, FIG. 3 is a right side view of FIG. 2, FIG. 4 is another half sectional view of the cylinder 15,
5 is a left half side view of FIG. 4, FIG. 6 is a sectional view taken along line AA of FIG. 4, and FIG. 7 is a sectional view taken along line BB of FIG. 2 to 7, reference numeral 15H denotes a cylinder body of the cylinder 15, and a step 15A is formed in the cylinder body 15H. Step 15A and recess 12 of anchor nut 12
B, a return spring 16 is interposed between the cylinder 15 and the upper cover 14.
Is urged upward. Further, another step 15B is formed in the cylinder body 15H, and when the cylinder 15 slides downward, the step 15B hits the end face 12D of the projection 12C of the anchor nut 12, but the sleeve 2
2 contacts the base end 12 </ b> E of the anchor nut 12. The head 23A of the piston 23 contacts the inner wall of the step 15B when tire pressure is not measured.

The cylinder body 15H has a small cylindrical portion 15C.
Are formed integrally with each other, a groove 15I in which the O-ring 17 is mounted is formed on the outer periphery of the small cylindrical portion 15C, and the slope 1 is formed inside.
5D is formed. As shown in FIGS. 4 to 6, a pair of substantially semicircular holes 15J is formed along the slope 15D. One part 22B of the sleeve 22 is inserted into the hole 15J. A bridge portion 15K is formed in the small cylindrical portion 15C, and a push rod 15G protrudes from the bridge portion 15K and is integrally formed. An air pressure chamber 25 is formed between the slope 15D and the sleeve 22, and when the push rod 15G pushes the shaft to open the valve of the tire, air pressure is introduced into the air pressure chamber 25.

A pair of substantially semicircular extending portions 15E extending upward are integrally formed at the opposite end of the small cylindrical portion 15C of the cylinder body 15H. A pair of slit portions 15L are formed between the extending portions 15E. A display section 15F is provided by printing on the pair of extending sections 15E, and the display section 15F displays a scale and a numerical value for pressure display.

Further, the piston 23 is provided in the slit 15L.
The ears 23C are fitted to each other, and move up and down between the slits 15L to support the pressure. The slit portion 15L is formed with a curved bottom surface, and the ear portion 23C having a curved end surface is fitted into the slit portion 15L, so that the ear portion 23C and the display portion 15F have the same cylindrical surface. I have. 8 to 11 are views showing the sleeve 22. FIG.

FIG. 8 is a half sectional view of the sleeve 22, FIG. 9 is a left side view of FIG. 8, FIG. 10 is a right side view of FIG. 8, and FIG. 8 to 11, reference numeral 22A denotes a sleeve main body of the sleeve 22, and a pair of two parts 22B are formed integrally with the sleeve main body 22A, and a bent part 22C is formed at an end of the two parts 22B. . One part 22B is a small cylindrical part 15C of the cylinder 15.
Is inserted into a pair of substantially semicircular holes 15J of the sleeve 22.
Is fitted to the cylinder 15 so as not to come off the cylinder 15. Also, one part 22B and one part 22
Between B, a pair of notches 22D are formed. A round hole 22E is formed at the center of the sleeve main body 22A, and the air pressure acts on the head 23A of the piston 23 through the round hole 22E in addition to the air pressure chamber 25.

When the cylinder 15 slides downward,
The sleeve 22 also slides down integrally, and the bent portion 22C of the sleeve 22 is brought into contact with the base end 12E of the anchor nut 12 before the step 15B of the cylinder 15 abuts against the end surface 12D of the projection 12C of the anchor nut 12. Abut,
The piston 23 is slightly moved upward.

Next, the operation will be described. When air is introduced into the tire tube, the tire valve cap 1
3 is screwed into the valve base attached to the air port of the tire tube in the same manner as a normal valve cap. This state is shown in the left half of FIG. 1, and the push rod 15G of the cylinder 15 is not in contact with the axis of the tire valve. For this reason, the valve is closed, the air pressure in the tire tube does not act on the piston 23, and the center hole 12F, the air pressure chamber 25, and the space 18 are in an atmospheric pressure state. The cylinder 15 and the upper cover 14 are pushed upward by a return spring 16.
Since no air pressure acts on the piston 23 housed in the cylinder 15, the piston 23 is urged by the pressure spring 26 and the head 23 </ b> A
Is in contact with the inner wall of

When the upper cover 14 is pushed in to check the tire pressure, the upper cover 14 and the cylinder 15 move downward integrally against the return spring 16 as shown in the right half of FIG. The step 15B of the cylinder 15 is the end face 1 of the projection 12C of the anchor nut 12.
Upon contact with 2D, the downward movement of the upper cover 14 and the cylinder 15 stops.

At this time, before the step 15B of the cylinder 15 comes into contact with the end surface 12D of the projection 12C of the anchor nut 12, the sleeve 22 comes into contact with the base end 12E of the anchor nut 12. That is, the length a of the sleeve 22
Is larger than the sum b of the length of the projection 12C of the anchor nut 12 and the thickness of the step 15B of the cylinder 15, so that the piston 23 is pushed upward by the sleeve 22 and a-b
Move by the dimension of. Therefore, the O-ring 17 mounted on the cylinder 15 also moves.

On the other hand, when the push rod 15G of the cylinder 15 pushes the axis of the tire valve due to the downward movement of the cylinder 15, the tire valve opens. When the tire valve opens, the air pressure in the tube passes through the center hole 12F of the anchor nut 12 and the round hole 2 of the sleeve 22.
2E and the pneumatic chamber 25, and the head 2 of the piston 23
Acting on 3A, pushes piston 23 upward. Therefore, the piston 23 moves upward to a position that balances the sum of the air pressure in the chamber 28 behind the piston 23 and the spring force of the pressure spring 26.

When the upper cover 14 is pushed and the cylinder 15 moves downward integrally with the upper cover 14, the O-ring 17 mounted on the cylinder 15 comes into contact with the inner wall of the projection 12C of the anchor nut 12, and The space 18 is divided into two spaces 18A and 18B. The pressure in the space 18A becomes the same high pressure as the pressure in the tire, and the space 18B
The air inside the gap 1 between the upper cover 14 and the lower cover 11
9 and enters the space 20 and exits through the gap 21 between the upper cover 14 and the lower cover 11.

Thus, when the piston 23 moves upward, the ear 23C moves upward in the slit 15L in accordance with the tire pressure, and the tire pressure can be easily read by reading the scale on the display 15F when it stops. Can be measured. In this embodiment, the step 15 of the cylinder 15 is used.
Before B contacts the end surface 12D of the projection 12C of the anchor nut 12, the sleeve 22 contacts the base end portion 22E of the anchor nut 12, so that the sleeve 22 can move the piston 23 slightly upward. Therefore, the O-ring 24 mounted on the piston 23 can be moved slightly upward. When the tire pressure is measured after leaving the tire pressure measurement for a long time, the O-ring 24 is stuck to the inner wall of the cylinder 15 even if the upper cover 14 is pushed in. The grease along the O-ring 24 and the inner wall of the cylinder 15 is pushed for a long period of time. This is because the dynamic resistance increases. In this state, since the piston 23 is moved by the sleeve 22 in addition to the air pressure, the tire pressure can be smoothly measured.

That is, in the measurement of the tire pressure, the upper cover 14 is pushed to open the valve of the tire. By using this force, the piston 23 is slightly moved by the sleeve 22 to smoothly measure the tire pressure. It can be performed. Next, FIGS. 12 to 16 show another embodiment of the present invention. 12 is a diagram showing a situation before measurement of the air pressure measuring device, FIG. 13 is a diagram showing a situation of starting measurement of the air pressure measuring device, FIG. 14 is a left side view of FIG. 13, and FIG.
3 is a right side view, and FIG. 16 is a diagram showing a situation at the time of measurement by the air pressure measuring device.

In the present embodiment, the technical idea of slightly moving the sticking of the O-ring by pressing force is applied to a rod-shaped air pressure measuring instrument which has been widely used in the general market. 12 to 16, 3
Reference numeral 1 denotes a body, in which a housing hole 31A is formed in the body 31, and an outer cylinder 32 is inserted into the housing hole 31A.

Thus, the outer cylinder 32 is fixed to the body 31. A pressure display rod 33 for displaying pressure is slidably housed in the outer cylinder 32, and an indication line for indicating pressure and a pressure value are displayed on the surface of the pressure display rod 33.
A seal portion 34 is fixed to one end of the pressure indicating rod 33, and the material of the seal portion 34 is formed of rubber. A guide 35 made of plastic is inserted and fixed to an end of the outer cylinder 32, and a pressure indicating rod 33 penetrates the guide 35. Step 31B in storage hole 31A of body 31
A packing 36 is housed therein, and a projection 37 is housed in contact with the packing 36. An air hole 37A is formed in the projection 37, and a slit 37B is formed at the tip of the projection 37.
Are formed. The protrusion 37 is provided in the storage hole 31 of the body 31.
A is slidably housed in A, and slides slightly when starting the measurement to move the seal portion 34.

FIG. 12 shows a situation where the air pressure measuring device 38 is not used. In this situation, the tip of the projection 37 is flush with the end surface of the storage hole 31A of the body 31, and the packing 36 is formed by the step 31B of the storage hole 31A.
Is in contact with Further, the projection 37 is in close contact with the seal portion 34, and the pressure indicating rod 33 is housed in the outer cylinder 32 and is in a stationary state.

Next, FIG. 13 to FIG.
Shows the situation in which was started. When the body 31 is pushed into the valve of the tire, the projection 37 slightly moves rightward, and the packing 36 also moves rightward. Therefore, the seal portion 34 is slightly pushed rightward by being pushed by the projection 37. Therefore, the end of the pressure indicating rod 33 slightly protrudes from the outer cylinder 32.

Next, FIG. 16 shows a situation at the time of measurement by the air pressure measuring device 38. The air pressure of the tire valve passes through the slit 37B of the projection 37, passes through the air hole 37A, and the seal portion 34.
To move the seal portion 34. Therefore, the pressure indicating rod 33 moves rightward while being guided by the guide 35. At this time, the air pressure can be measured by reading the pressure value of the pressure display rod 33 protruding from the outer cylinder 32.

In the prior art, since the projection 37 pressing the seal portion 34 is fixed in the body 31, the seal portion 3
4 sticks inside the outer cylinder 32. For this reason, the air pressure is repeatedly used or pressed many times to give an air pressure, or the air pressure measuring device 38 is hit and moved. In this embodiment, the projection 37 is slidably housed in the body 31 and the projection 37 is slightly moved to press the seal portion 34 during measurement, so that the tire pressure can be smoothly measured.

In many cases, the rod-shaped air pressure measuring device 38 has a bent head, but even if it is bent, it is easy to start the seal portion 34 with a pressing force for measurement.

[0041]

As described above, according to the present invention, when the opening / closing member is pushed in for measuring the tire pressure, the sleeve is connected to the base end of the anchor nut member before the opening / closing member hits the projection of the anchor nut member. The moving member is slightly moved by contacting the
Since the ring also moves slightly, the measurement can be performed smoothly without sticking the ring.

Further, even in a normal rod-shaped air pressure measuring device, the seal portion is slightly pressed by the projection, so that the seal portion can be smoothly measured without sticking to the outer cylinder.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a half sectional view of a cylinder.

FIG. 3 is a right side view of FIG. 2;

FIG. 4 is another half sectional view of a cylinder.

FIG. 5 is a left half side view of FIG. 4;

6 is a sectional view taken along the line AA of FIG. 4;

FIG. 7 is a sectional view taken along the line BB of FIG. 4;

FIG. 8 is a half sectional view of a sleeve.

FIG. 9 is a left side view of FIG. 8;

FIG. 10 is a right side view of FIG.

FIG. 11 is another half sectional view of the sleeve.

FIG. 12 is a sectional view showing a state before use according to another embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a starting state.

FIG. 14 is a left side view of FIG.

FIG. 15 is a right side view of FIG.

FIG. 16 is a sectional view showing a situation at the time of measurement.

FIG. 17 shows a conventional example.

[Explanation of symbols]

 11: Lower cover 11A: Projection 11B: Serration 12: Anchor nut (anchor nut member) 12A: Spline 12B: Recess 12C: Projection 12D: End face 12E: Base end 12F: Center hole 12G: Screw 13: Tire valve cap 14: Upper cover 15: Cylinder (opening / closing member) 15A, 15B: Step 15C: Small cylindrical portion 15D: Slope 15E: Extension 15F: Display 15G: Push rod 15H: Cylinder body 15I: Groove 15J: Hole 15K: Bridge 15L: slit portion 16: return spring 17, 24: O-ring 18, 18A, 18B, 20: space 19, 21: gap 22: sleeve 22A: sleeve body 22B: one portion 22C: bent portion 22D: notched portion 22E : Round hole 23: Piston (opening / closing member) 3A: Head 23B: Step 23C: Ear 25: Pneumatic chamber 26: Pressure spring 27: Disc 28: Chamber 31: Body 31A: Storage hole 31B: Step 32: Outer cylinder 33: Pressure display rod 34: Seal part 35: Guide 36: Packing 37: Projection 37A: Air hole 37B: Slit 38: Air pressure measuring instrument

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01L 7/00 F16K 15/20 F16K 37/00

Claims (4)

(57) [Claims] 1. An upper cover and a rotatable member integrally provided with the upper cover. The valve is opened when a valve of a tire tube is opened by moving in an axial direction to introduce air pressure, and the valve is closed when the tire is not moved. An opening / closing member, comprising a moving member housed in the opening / closing member and moving by air pressure introduced from the opening / closing member, wherein when the opening / closing member is pushed in for measuring tire pressure, the opening / closing member moves the opening / closing member through an elastic member. A tire valve cap comprising a sleeve for slightly moving the moving member by hitting a base end of the anchor nut member before hitting a projection of the anchor nut member to be supported. 2. The tire according to claim 1, wherein the length of the sleeve is greater than the sum of the length of the protrusion of the anchor nut member and the thickness of the step of the opening / closing member abutting on the protrusion. Valve cap. 3. The sleeve according to claim 1, wherein the sleeve has a pair of two portions, and the two portions are inserted into a substantially semicircular hole provided in a small cylindrical portion of the opening / closing member. Tire valve cap. 4. An outer cylinder inserted into a body, a pressure indicator rod housed in the outer cylinder, having a seal portion at an end and moving by air pressure, and an air hole movably housed in the body. An air pressure measuring device, comprising: a projection for slightly moving the seal portion.