VENTING VALVE AND METHOD OF MOUNTING VALVE STEM OF VENTING VALVE

Abstract

A venting valve and method of mounting a valve stem of a venting valve. The venting valve (3) comprises a valve body (4) inside which is a venting channel (5) which is provided with a movable valve stem (6) comprising a valve member (7) and a collar (8) at an opposite end of the valve stem. A spring element (9) is arranged around the valve stem. Movement of the valve stem is limited by means of an external retaining ring (11) mounted to an external retaining groove (12) of the valve body. Bottom of the retaining groove comprise openings extending to the venting channel and the retaining ring partly protrudes inside the venting channel through the openings, whereby the protruding parts of the retaining ring are configured to form retaining surfaces (15) preventing the collar to pass them.

Claims

1. A venting valve for removing air from a vulcanising mould of a vehicle tire, wherein the venting valve comprises: a valve body comprising a first end configured to face towards an interior of the vulcanising mould and a second end configured to face away from the interior of the vulcanising mould; a venting channel passing longitudinally through the valve body; a movable valve stem arranged inside the venting channel and comprising a first end provided with a valve member for opening and closing the venting channel, and a second end having a collar; a spring element for pressing the movable valve stem in an opening direction towards an opening position wherein air flow through the venting channel is allowed; and a locking element which is located at a second end of the valve body and is configured to limit movement of the movable valve stem in the opening direction, wherein the locking element is an external retaining ring wherein the second end of the valve body includes a retaining groove on an outer surface of the valve body to receive the external retaining ring, wherein a bottom of the retaining groove includes at least two slits forming openings extending to the venting channel, and wherein the external retaining ring is mounted inside the retaining groove, and wherein the external retaining ring is configured to partly protrude inside the venting channel such that protruding parts of the external retaining ring are configured to form retaining surfaces to prevent the collar from passing the retaining surfaces.

2. The venting valve of claim 1, wherein the valve body comprises two slits on opposite sides of the valve body.

3. The venting valve of claim 1, wherein the external retaining ring is an elastically deformable element which has a basic shape and is expandable to greater dimensions.

4. The venting valve of claim 1, wherein the collar includes a first conical surface that is facing the second end of the valve body, wherein the first conical surface is configured to cause the external retaining ring to expand when the movable valve stem is mounted inside the venting channel.

5. The venting valve of claim 4, wherein the collar includes with a second conical surface that is facing the first end of the valve body, wherein the second conical surface is configured to cause the external retaining ring to expand when the movable valve stem is removed from the venting channel by pushing the external retaining ring towards the first end of the valve body.

6. The venting valve of claim 4, wherein the second end of the valve body comprises support surfaces inside the venting channel, wherein the support surfaces are facing towards the first end of the valve body; and wherein the spring element is supported against the support surfaces.

7. The venting valve of claim 1, wherein the external retaining ring is configured to provide axial support for the spring element.

8. The venting valve of claim 1, wherein the external retaining ring is configured to provide lateral support for the movable valve stem.

9. The venting valve claim 1, wherein the movable valve stem and the collar have a solid configuration.

10. The venting valve claim 1, wherein the external retaining ring comprises at least two lugs protruding radially towards a central part of the external retaining ring.

11. A method of mounting a valve stem of a venting valve that includes a valve body provided with a longitudinal venting channel, wherein the method comprises: pushing the valve stem under an external mounting force longitudinally in a mounting direction inside the longitudinal venting channel against a spring force generated by means of a spring element; and providing the valve stem with a collar; and preventing the valve stem from escaping from the longitudinal venting channel using a locking element supported against the collar when the external mounting force is removed and the spring force tries to move the valve stem against the mounting direction; wherein preventing the valve stem from escaping from the longitudinal venting channel comprises, using an external retaining ring as the locking element; mounting the external retaining ring in a lateral direction to a retaining groove formed on an outer surface of the valve body; allowing the external retaining ring to expand radially during assembly and to return into an original shape after being released into the retaining groove; and allowing the external retaining ring to partly protrude at selected locations inside the longitudinal venting channel and to form retaining surfaces to prevent passing of the collar after the external retaining ring is in its the original shape without being expanded.

12. The method of claim 11, further comprising providing lateral support for the valve stem using protruding parts of the external retaining ring.

13. The method of claim 11, wherein allowing the external retaining ring to expand radially comprises allowing the external retaining ring to expand radially using conical surfaces of the collar when pushing the valve stem axially towards the mounting direction and correspondingly pushing the valve stem in an opposite direction when dismounting the valve stem.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0036] Some embodiments are described in more detail in the accompanying drawings, in which

[0037] FIG. 1 is a schematic and partly sectional view of a venting valve mounted to a venting bore of a vulcanization mold,

[0038] FIG. 2 is a schematic and sectional side view of a venting valve provided with an external retaining ring mounted to an external retaining groove,

[0039] FIG. 3 is a schematic view of a cross section A-A of FIG. 2,

[0040] FIG. 4 is a schematic side view of a valve stem mountable inside a central venting channel of the venting valve,

[0041] FIG. 5 is a schematic side view of a retainer ring,

[0042] FIG. 6 is a schematic side view of another venting valve wherein the retainer ring provides support for a to spring element, and

[0043] FIG. 7 is a schematic view of a cross section A-A of FIG. 6.

[0044] For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0045] FIG. 1 discloses a venting bore 1 of a vulcanization mold 2. The bore 1 has a first opening 1a at an inner side of the mould and a second opening at second side of the mould (not shown). The bore 1 is provided with a venting valve 3. Air inside of the mold can be vented through the venting valve 3 and the bore 1 out of the mold and the venting valve 3 is intended to be closed before material of the tire so that the tire material will not plug the venting bore 1.

[0046] Let it be mentioned that in this document terms tyre and tire mean the same as well as the terms mold and mould.

[0047] FIG. 2 discloses a venting valve 3 comprising a valve body 4 provided with a first end 4a and a second end 4b. The first end 4a is facing towards an interior of the mould and the second end 4b is facing away from the interior of the mold. The valve body 4 is further provided with a central venting channel 5 via which the vented air is configured to flow. In other words, the valve body is an elongated sleeve-like element comprising an outer surface and inner surface. The outer surface may form a friction locking with surfaces of the venting bore. A valve stem 6 is mounted inside the venting channel 5. The valve stem 6 is axially movable relative to the valve body 4 for a limited distance. The valve stem 6 comprises a first end 6a provided with a valve member 7 for opening and closing the venting channel 5. The valve member 7 comprises a top surface 7a and conical sealing surfaces 7b. A second end 6b of the valve stem 6 is provided with a collar 8. The collar 8 is an enlarged portion at a distal end of the valve stem 6 and the collar 6 may be provided with a first conical surface 8a and a second conical surface. A spring element 9 is arranged to press the valve stem 6 in opening direction B towards an opening position wherein air flow C through the venting channel 5 is allowed. The spring element 9 may be a helical spring, for example. Tire blank material fed inside the mold presses the valve member 7 against spring force generated by the spring element 9 and closes a gap between the sealing surfaces 7b of the valve member 7 and mating sealing surfaces of the valve body 4. In other words, the tire blank moves the valve stem in closing direction D. The valve stem 6 and the spring element 9 form together a valve insert 10 mounted inside the valve body 4.

[0048] The venting valve 3 further comprises a locking arrangement 13 or system which is located at a second end portion 4b of the valve body 4 and is configured to limit the movement of the valve stem 6 in the opening direction B. The locking arrangement 13 comprises an external retaining ring 11 which serves as a mechanical locking element. The second end part 4b of the valve body 4 is provided with a retaining groove 12 on its outer surface for receiving the retaining ring 11. A bottom of the retaining groove 12 is provided with two or more slits 14 forming openings extending to the venting channel 5. Then the retaining ring 11 mounted inside the retaining groove 12 can partly protrude inside the venting channel 5. Protruding parts 11a of the retaining ring 11 are configured to form retaining surfaces 15 facing towards the collar 8 and preventing the collar 8 to pass the preventing surfaces 15. The protruding parts 11a of the retaining ring 11 are shown also in FIG. 3.

[0049] Since the collar 8 has the first conical surface 8a and the second conical surface 8b, the valve stem 6 can be easily mounted by pushing it axially inside the venting channel 5, and can be correspondingly easily removed by pushing it axially in the opposite direction if the valve insert needs to be replaced. The conical surfaces 8a, 8b will smoothly expand the retaining ring 11 when the valve stem 8 is forced to move axially by means of external mounting force. The outwardly directed expansion E is shown in FIG. 3 by means of arrows.

[0050] In the embodiment shown in FIG. 2 the spring element 9 is supported at the second end 4b by means of a shoulder 16 of the valve body 4.

[0051] In another embodiment shown in FIG. 6 the protruding parts 11a of the retaining ring 11 are configured not only to form retaining surfaces 15 for the collar 8 but also to provide support surface 17 for the spring element 9. Thus, in this solution the retaining ring 11 has two purposes. The structure of the venting body 4 may be even simpler when there is no need to arrange a fixed shoulder for the spring element.

[0052] In FIG. 3 mounting direction M of the retaining ring 11 is shown by means of an arrow. The retaining ring 11 may be already mounted to the valve body and only thereafter the valve stem 6 is pushed along the venting channel towards the second end 4b. Then the first conical surface 8a facing the second end 4b cause the retaining ring 11 to expand and allow the collar 8 to pass the retaining ring 11.

[0053] Inner surfaces of the lugs 11a provide support for the valve stem 6 in lateral direction L. Between the shoulder and the valve stem 6 is an annular gap allowing removed air to pass the shoulder. Therefore, the shoulder does not provide any lateral support for the valve stem in the solution disclosed in FIG. 2.

[0054] The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.