ARRANGEMENT IN STUDDED TIRES

Abstract: An arrangement in studded tire with retractable studs (7), including a movable wall (3) which defines an air chamber (4) together with the inside (2) of the tire, said chamber being inflatable for urging the studs attached to the wall out through passages (1a) in the tread of the tire. The arrangement also includes locking means (6, 10, 18-20) in the tire in association with the passages (1a) for locking the studs (7) in their protrudent position.

Description: Arrangement in Studded Tires Technical Field The present invention relates to an arrangement in studded tires with retractable studs, and includes a movable wall defining together with the inside of the tire an air chamber, which may be inflated for moving the studs fastened to the wall out through passages in the tread of the tire. Background Art Studded tires with fixed studs are often used the whole winter, even on good road surfaces. The studs wear away the road paving and are themselves worn down, with deteriorated safety as a result. Such wear costs large sums of money every year, which is the reason for studded tires being prohibited in some countries. It has been attempted to solve the above- mentioned problems by arranging the studs retractable. In such a case they are attached to a movable wall inside the tire, this wall defining together with the inside of the tire an air chamber which may be inflated for thrusting the studs out through passages in the tread of the tire. Examples of such arrangements are to be found in DE-OS 1 680 491, DE-OS 2 602 544 and US-PS 3 340 921. However, these arrangements are burdened with disadvantages, of which the greatest is that the studs are pressed back into the tire during travel, their function thus being deteriorated or even entirely inhibited during emergency braking. Disclosure of the Invention The object of the present invention is to obviate the disadvantages with which previously known arrange- ments of the kind mentioned above are burdened, and to provide a simple and reliable arrangement where the studs may be retracted and protruded such as to be locked in their protrudent state, the arrangement being such as to ensure a fully effective seal between the studs and the tire as well as a decreased risk of punctures. This object is achieved primarily by locking means in the tire in association with the passages mentioned, these means being adapted to. lock the studs in their protrudent positions for desired periods, the object also being achieved with the aid of the characterizing features disclosed in the subclaims. Description of Figures Figure 1 is a section through a part of a schematically illustrated tire provided with an arrangement in accordance with the invention, a stud being shown in a retracted, first position, and Figure 2 is a section substantially correspond¬ ing to the one in Figure 1 but with the arrangement being illustrated with a stud in a protrudent second position. Preferred Embodiment The tire provided with an arrangement in accordance with the invention has a tread denoted by 1 and an inner lining denoted by 2. An interior wall 3 movably accommodated in an unillustrated way inside the tire forms a closed chamber 4 together with the lining 2. A stud anchor 5 is fixed to the wall 3, and wedging rods 6 are fixed to the anchor. A stud 7, provided at either end with a hexagonal socket 8, 11, is screwed tightly into the anchor 5 such that the socket 8 is accessible from the inward side of the tire via a passage 9 in the anchor. A locking and sealing sleeve 10 is fixed in the tire with the aid of a flange 10a on the sleeve. The stud 7 is accommodated in the sleeve for reciprocating, longitudinal movement such that the active end of the stud can project out from a passage 1a in the tire tread. An upper sealing ring 12 seals between an upper cylindrical portion 14 of the stud and a bore 16 in the sleeve 10, and a lower seal¬ ing ring 13 seals between a lower conical portion 15 of the stud 7 and a passage 17 in the sleeve 10 complemental "to the conical portion 15. The sleeve 10 is also provided with bores 18 for the wedging rods 6, and bores 19 for balls 20. The conical passage 17 is provided with rubber cladding 21 for also sealing against the conical portion 15 of the stud 7. The inner wall 3 is provided with a hole 22, from which a hose 23 extends to a valve 25 threaded on to an attachment plate 24 attached to the rim on which the tire is mounted. The valve 25 is provided with a valve needle 26 and is externally threaded for meshing with the interior thread of a two chamber nipple 27 provided with an inner pin 28 and vent hole 29. This nipple is suitably hexagonal in cross section, is internally threaded at either end and is reversible. In one position, the pin 28 can depress the needle 26, thus allowing venting of the air in the chamber 4 via the vent hole 29. In the reverse position of the nipple it is not possible to vent the chamber, but air may be pumped into it. The nipple is also provided with a protective cap 30, which has an external thread for screwing into either end of the nipple, as well as wings 32 and a hexagonal socket 31 fitting the body of the nipple. When the tire is fitted and inflated, the movable inner wall 3 is pressed a-gainst the lining 2, as illustrated in Figure 2, and the studs then protrude out " through the tread 1, i.e. they are in an active position. The studs 7 are locked in this position by the balls 20 which are forced out against the conical part 15 of the stud by the wedging rods 6 when the latter are moved upwards from the position in Figure 1 , due the inflation. When the stud 7 is subjected to an external force, i.e. when it is urged into the tire as it comes into contact with the road, it is pressed against the locking balls 20, which are in turn urged against the tips of the wedging rods 6, the stud thus being rigidly locked and prevented from being forced back into the tire. When the road surface is. good and the studs are not needed, air is pumped into the chamber 4 via the valve 25, causing the inner wall 3 to be urged away from the lining 2, taking the studs 7 with it, thus causing them to be retracted into the tire, as illustrated in Figure 1. Further movement of the stud is stopped by the locking-sealing sleeve 10, the conical portion 15 on the stud engaging with its complementary conical portion 17 of the sleeve via the rubber cladding 21 , to ensure, that the air chamber is airtight. When the state of roads and the like is such that more traction is required from -the. tire, the air is let out from the chamber 4 by screwing the two- chamber nipple 27 αi j the-valve--25 so. that the pin 28 depresses the valve needle 26. In order that the two- chamber nipple 27 may be easily screwed off from the valve 25 the cap 30 is provided with wings 32 and the hexagonal socket 31 fitting the body of. the nipple 27. Although, only one embodiment of the invention has been described above and illustrated on the accompanying drawings, it will be understood that the invention is not limited to this embodiment but only by the disclosures in the claims.

Claims: CLAIMS 1. Arrangement in studded tires with retractable studs (7) , including a movable wall (3) defining an air chamber (4) together with the inside (2) of the tire, said chamber being inflatable for moving the studs fastened to the wall out through passages (1a) in the tread (1) of the tire, characterized, by locking means (6, 10, 18 - 20) arranged in association with said passages (1a) for locking the studs (7) in their protrudent positions. 2. Arrangement as claimed in claim 1, characterized in that the locking means (6, 10, 18 - 20) include a sleeve (10) fastened in the tire and surrounding each stud, there being locking balls (20) movably accommodated in the sleeve for locking engagement between a conical portion (15) on the stud (7) and rods (6) attached to the movable wall (3) and projecting into the sleeve, when the stud is in its protrudent. position. 3. Arrangement as claimed in cla * Lm 2, characterized in that the rods (6) are attached to an anchor (5) on which the stud (7) is threaded. 4. Arrangement as claimed in claim 1, 2 or 3, characterized by a seal (21) mounted in association with the locking means (6, 10, 18 - 20) and the stud (7) for sealing engagement between the stud and tire when the stud is in its retracted position. 5. Arrangement as claimed in claim 2 and 4, characterized in that the seal comprises rubber cladding (21) on the conical passage (17) of the sleeve (10). 6. Arrangement as claimed in any one of the . preceding claims, characterized in that the air chamber (4) is connected to a valve (25) by a reversible nipple (27) removable from the valve, for sealing it and venting air from it. 7. Arrangement as claimed in claim 6, characterized by a cap (30) removably mounted on the nipple (27) and provided with means for removing the nipple from the valve

Inventors: GULLBRANDSSON BO OLAV, GULLBRANDSSON, BO, OLAV
Applicants: GULLBRANDSSON BO OLAV, GULLBRANDSSON, BO, OLAV
Application year: 1986
Main classification: B60C11
IPC codes: B60C11