CROSS BELT DEVICE FOR COVERING TIRE OF AUTOMOBILE TRAVELLING ON SNOW-COVERED ROAD

Abstract: The cross belt device is fitted around a tire of an automobile, which is to travel on a snow-covered road, to prevent the tire from slipping. In a cross belt device (1), an outer ring (4) is supported rotatably on an inner ring (3) secured detachably to a wheel (2) of an automobile, and a number of elastically deformable leaf springs (7) are attached radially to this outer ring, cross belts (8) extending across a tread surface (12a) of a tire being connected at one end of each thereof to the outer end portions of the leaf springs and at the other ends thereof to an endless outer circumferential strap (9). The cross belts are adapted to be turned from the positions on the tread surface to the positions away from the tread surface, and vice versa by utilising the elastic deformation of the leaf springs. When the diameter of the tire varies due to the flexure of the ground-contacting portion thereof occurring while the automobile runs on a road, or, when the cross belts are displaced on the tread surface in the circumferential direction while the automobile runs, the variation of the diameter and the displacement of the cross belts are offset by the elastic deformation of the leaf springs and the rotation of the outer ring.

Description: This invention relates to an anti-slip device for use with a vehicle tyre, which is attached to a vehicle tyre to prevent slipping during travel on snow-covered roads. In a prior applications, Japanese Patent Application 63-155675, the present inventor proposed an anti-slip device which is composed of a main body detachably attachable to the outer side of an automobile wheel, a plurality of leaf springs operable to turn in both forward and reverse directions about the respective axes and extended radially outward from the main body, and anti-slip crossbands attached to the fore ends of the leaf springs to lie in abutting contact with the tread surface of the tyre to prevent slipping. When driving on a snowy road, this cross-band device is attached to the outer side of an automobile wheel, and the crossbands are brought into abutting engagement with the tread surface of the tyre by turning the leaf springs. When not used, the crossbands are displaced into receded positions away from the tread surface by turning the leaf springs, and then the device is removed from the automobile wheel and put away in a folded state in the boot or other suitable place in the vehicle. The above-described device has advantages that it can be easily attached to the outer side of an automobile wheel by the use of wheel nuts and that, when not necessary, it can be removed from the wheel and folded into a compact form suitable for storage in the boot of the vehicle. However, the leaf springs are turned in the forward and reverse directions by a handle operation through a gear mechanism, which is complicate in construction, troublesome to manipulate, and high in production cast. Further, it is important for a device of this sort to take into account the variations in tyre diameter which occur during travel of a vehicle due to flexing of the ground-contacting portion of the tyre, as well as the displacements of the crossbands in the circumferential direction along the tread surface at the ground-contacting portion of the tyre. Document WO84/04071 describes an anti-skid device for vehicles which has a central fixing means for attaching the device to a vehicle wheel, a number of outwardly extending spokes, and a continuous belt attached to the outer ends of these spokes. The continuous belt extends the whole way around and covers the tread of the existing tyre plus a portion of the side wall of the tyre. A problem with such a device is that, when travelling on a snow-covered road, that continuous belt becomes displaced sideways and is forced off the tread of the tyre in the area where contact with the ground is made. Such a device is not satisfactory therefore in providing grip. According to the invention there is provided an anti-slip device for use with a vehicle tyre on a snowy road, comprising an inner member detachably fixable to the outer side of a vehicle wheel through the wheel nuts, an outer ring supported by the inner member rotatably about the centre axis thereof to follow movements of the device in the circumferential direction along the tread surface of the tyre, and a number of elastically deformable leaf springs extending radially outwardly from the outer ring, characterised in that an anti-slip crossband is contiguously connected to the outer end of each leaf spring and extends crosswise of the tread surface of the tyre, and a circumferential band interconnects the crossbands at one edge of the tread of the tyre. An anti-slip device for use on snowy roads according to the invention can be inexpensive and of simple construction dispensing with the complicate rotational operating mechanism including a handle and gears, and which permits to turn the leaf springs easily and securely to move the crossbands to and from a position in abutting engagement with the tread surface of a tyre and a position away from the tread surface, while coping with variations in tyre diameter and displacements of the crossbands in a reliable manner during vehicle travel. With the device of the invention, after attaching the inner member to the outer side of an automobile wheel through wheel nuts, the crossbands can be positioned in intersecting relation with the tread surface of the tyre simply through elastic deformation of the respective leaf springs. At this time, the circumferential band and crossbands cannot be placed under the tread surface at the ground-contacting portion of the tyre. However, since the leaf springs at that portion are in flexed state, the circumferential band and crossbands can be automatically urged into positions under the tread surface by the resiliency of the leaf springs upon moving the vehicle slightly forward or backward. The variations in tyre diameter, which occur as a result of flexing of the ground-contacting portion of the tyre when the vehicle is in travel, are absorbed by elastic deformation of the leaf springs, while the displacements of the crossbands, which occur in the circumferential direction along the tread surface at the ground-contacting portion, are absorbed by rotation of the outer ring and flexing of the leaf springs, thereby preventing fracturing damages of the crossbands and leaf springs. When the anti-slip device is not needed, it can be removed from the wheel by detaching the inner member from the wheel nuts and taking the circumferential band and the respective crossbands away from the tread surface of the tyre. On such an occasion, although the crossbands and circumferential band at the ground-contacting portion are trapped under the tyre and therefore cannot be immediately removed therefrom, they can be released by moving the vehicle slightly forward or backward after laying other portions of the device flat on the ground. In this manner, the device according to the invention can be easily attached to or detached from a car wheel. Besides, simply by elastic deformation of the leaf springs, the crossbands can be turned to and from a position in abutting engagement with the tread surface of a tyre and a position away from the tread surface, coupled with additional advantages such as extremely simplified construction and handling and low production cost. For the purpose of mounting the crossband device on a vehicle wheel, the inner member is centrally provided with a mounting portion which can be fixed accurately to a predetermined position on the wheel. As means for supporting the outer ring rotatably on the inner ring, it is preferred to provide a groove on one of the rings, more specifically, either around the outer periphery of the inner ring or around the inner periphery of the outer ring for sliding engagement with a fitting portion provided opposingly on the other ring. By the use of this arrangement, the construction of the support means can be simplified to a significant degree. The crossbands and circumferential band can each be constituted by a flat, strip-like band of a durable synthetic resin material, with metal spike pins planted on the outer side thereof. On the other hand, the leaf springs can each be formed of a flattened narrow strip of steel or a synthetic resin material. When using leaf springs of a synthetic resin material, they can be formed integrally with the crossbands. Further, the crossband may consist of a single linear strip or may be formed in V-shape if desired. The invention will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a vertical section of a crossband device embodying the present invention, the crossband device being fitted on a vehicle wheel; Figure 2 is a front view of the crossband device; Figure 3 is a plan view of major components of the device; and Figures 4 and 5 are views similar to Figure 3 but showing modifications of the crossband device of the invention. Referring to Figs. 1 and 2, there is illustrated an anti-slip device 1 of the invention, which is mounted on a vehicle wheel 2. The crossband device 1 has an inner ring 3 which is detachably fixable on wheel 2, and an outer ring 4 which is supported by the inner ring 3. The inner ring 3 is provided with a recessed mount portion 3a which is sunken toward the wheel 2 and concentrically fixable to the outer side of the wheel 2 by way of wheel nuts 2a. On the other hand, the outer ring 4 is provided with a groove 6 around its inner periphery for sliding engagement with a fitting portion 5 which is formed around the outer periphery of the inner ring 3. As a result, the outer ring 4 is supported by the inner ring 3 concentrically and relatively rotatably about the center axis of the inner ring 3. Conversely, the groove 6 may be formed around the outer periphery of the inner ring 3 and slidably engaged with a fitting portion which is formed around the inner periphery of the outer ring 4 if desired. Extended radially outward of the outer ring 4 are a suitable number of leaf springs 7 which are, for example, in the form of flattened narrow strips of steel or a synthetic resin material capable of elastic deformation such as bending and twisting and which has the respective base ends securely fixed to the outer ring 4 substantially at equidistant positions around the circumference of the latter. An anti-slip crossband 8 is contiguously attached to the fore end of each leaf spring 7 to extend crosswise of the tread surface 12a of a tyre 12. As seen in Fig. 3, the fore end of each crossband 8 is secured by a connector member 10 to an endless circumferential band 9 which interconnects the respective crossbands 8. The crossbands 8 and the circumferential band 9 are each constituted by planting a suitable number of metal spike pins 11 on the outer side of a flat strip-like band 8 or 9 of a durable synthetic resin material with excellent resistance to abrasive wear and coldness. Alternatively, other durable strips with anti-slip surfaces may be employed for the crossband 8 and the circumferential band 9. In case the leaf spring 7 of a synthetic resin material are employed, they may be formed integrally with the crossbands 8. The cross bands 8 are not restricted to a single linear strip as shown particularly in Fig. 3, and may be formed in an outwardly diverging V-shape as shown in Figs. 4 and 5 or in any other suitable shapes if desired. In order to use the crossband device of the above-described construction, the inner ring 3 is mounted on the outer side of the automobile wheel 2 through the wheel nuts 2a, and then the respective crossbands are abuttingly engaged with the tread surface 12a of the tire 12 in intersecting relation therewith by the use of resilient force of the leaf springs 7. At this time, the circumferential band 9 and crossbands 8 cannot be placed on the tread surface 12a at the ground-contacting portion of the tyre 12. However, since the leaf springs 7 which support the crossbands 8 are in resiliently flexed state at that portion, the circumferential band 9 and crossbands 8 can be automatically urged onto the ground-contacting tread surface by resilient restoring force of the leaf springs 7 as soon as the vehicle is moved slightly forward or backward. As mentioned hereinbefore, while the vehicle is in travel, variations in tyre diameter occur due to flexure of the tyre at the ground-contacting portion. These variations are suitably absorbed by bending deformation of the leaf springs 7. In case the crossbands 8 at the ground-contacting portion are displaced in the circumferential direction along the tread surface 12a of the tyre 12, these displacements are absorbed by flexure of the leaf springs 7 and rotation of the outer ring 4 to prevent fracturing damages of the crossbands 8 and leaf springs 7. When the crossband device becomes unnecessary, the inner ring 3 is detached from the wheel nuts 2a, and then the crossbands 8 are shifted into receded positions away from the tread surface 12a of the tyre 12 to remove the device 1 from the wheel 2. At this time, the crossbands 8 and circumferential band 9 at the ground-contacting portion are trodden by the tyre 12 so that they cannot be immediately removed therefrom. However, by moving the vehicle slightly forward or backward after laying other portions of the device 1 flatly on the ground, the crossbands 8 and the circumferential band 9 under the tyre can be readily removed from the tread surface 12a. The crossband device 1 which has been removed from the wheel 2 can be handily stored in the boot of the vehicle or the like.

Claims: An anti-slip device (1) for use with a vehicle tyre (12) on a snowy road, comprising an inner member (3) detachably fixable to the outer side of a vehicle wheel (2) through the wheel nuts (2a), an outer ring (4) supported by the inner member (3) rotatably about the centre axis thereof to follow movements of the device (1) in the circumferential direction along the tread surface (12a) of the tyre (12), and a number of elastically deformable leaf springs (7) extending radially outwardly from the outer ring (4), characterised in that an anti-slip crossband (8) is contiguously connected to the outer end of each leaf spring (7) and extends crosswise of the tread surface (12a) of the tyre (12), and a circumferential band (9) interconnects the crossbands (8) at one edge of the tread (12a) of the tyre (12). An anti-slip device as claimed in Claim 1 in which the inner member (3) is centrally provided with a mounting portion (3a) and is concentrically attachable to the outer side of the wheel (1) through that mounting portion (3a). An anti-slip device as claimed in Claim 1 or Claim 2 in which a groove is provided either around the outer periphery of the inner member (3) or around the inner periphery of the outer ring (4), and slidably engaged in that groove is the inner periphery of the outer ring (4) or the outer periphery of the inner member (3), respectively, thereby supporting the outer ring (4) rotatably on the inner member (3). An anti-slip device as claimed in any preceding claim in which the crossbands (8) and the circumferential band (9) are each constituted by flat strip-like bands of a durable synthetic resin material with metal spike pins (11) planted on the outer side thereof. An anti-slip device as claimed in any preceding claim in which the leaf springs (7) are each constituted by a flattened narrow strip of steel. An anti-slip device as claimed in any of claims 1 to 4 in which the leaf springs (7) are each formed of a synthetic resin material. An anti-slip device as claimed in Claim 6 in which the leaf springs (7) and crossbands (8) are integrally formed of a synthetic resin material. An anti-slip device as claimed in any preceding claim in which the crossbands (8) are each in the form of a single linear strip. An anti-slip device as claimed in any of claims 1 to 7 in which each crossband (8) is formed in a V-shape.

Inventors: KOSHI MASAKI, KOSHI, MASAKI
Applicants: KOSHI MASAKI, KOSHI, MASAKI
Application year: 1989
Main classification: B60C27
IPC codes: B60C27