Abstract:
This invention relates to a tire chain designed to retain the strength characteristics of a prior tire chain but reducing the dimension of the tire chain components to be located at the inner wall of the tire so as to reduce the likelihood of interfering engagement with components that are closely positioned relative to the tire.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to traction devices applied to vehicle tires for added gripping, e.g. on roads covered with ice or snow, and more particularly to a traction device structure that can be applied and used on vehicles wherein minimal clearance is provided at the sides of the tires whereat the devices (tire chains) are secured to the tire.  
       BACKGROUND OF THE INVENTION  
       [0002]     The use of tire chains on the drive wheels of vehicles is desirable for drivers who need to drive on snow or ice laden roadways. (Here the term “tire chains” has reference to all types of add-on traction devices, e.g. cable type as well as link type tire chains.) Such tire chains traditionally have been designed to withstand severe abuse and as so designed has been available and in use for decades. More recently, however, certain types of vehicles have been designed with less clearance at the inner side walls of the tires (as mounted on the vehicle) and the somewhat hefty design of the traditional tire chain does not have sufficient clearance to allow mounting of those chains onto the vehicle tires.  
         [0003]     This predicament has resulted in new tire chain designs to enable such vehicles to be equipped with the desired supplemental traction. One new chain design simply reduces the components of the device in size. This results in a weaker chain that is more likely to fail and, upon failure, can cause undesirable damage and potential injury. Another type is a claw type that provides resilient gripping fingers that fit over the tread but no other securement is provided at the inside of the tire. Such devices are expensive and prone to being dislodged from the tire, again with unsatisfactory consequences.  
         [0004]     It is accordingly an object of the present invention to provide a tire chain design that is of the more conventional type, i.e. secured at both the inside and outside of the tire, accommodates the lesser clearance but without sacrificing strength and integrity of the chain.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0005]     The resolution of this problem is believed to be the separate consideration of the hereafter defined two major compositions of the tire chain. Those major compositions are first, that portion of the chain that spans the bottom surface of the tire tread to produce enhanced gripping of the tire to the road surface, e.g. when the road surface is covered with ice or snow; and second, that portion of the tire chain that produces securement of the chain to the tire.  
         [0006]     Tire chains for which the present invention is primarily intended includes side members, cross members and connectors. The first major composition of these chains, as per the above definition, is the center portions only of the cross members. That is, the cross members extend from a position at one side wall of a tire radiating outwardly to the tread and across the lateral surface of a tread and then radially inwardly to the opposing side member. That portion of the cross member that extends across the lateral surface of the tread (and which becomes interposed between the tread and a road surface during operation) is considered to be the first major composition of the tire chain.  
         [0007]     The criteria for this first major composition, i.e., the center portion of the cross members, is that it have the strength to withstand the impact and abrasion experienced from normal vehicle operation, and secondly, that it provide enhanced traction, e.g. for reducing tire slippage on ice and snow laden roadways.  
         [0008]     The second major composition of the tire chain is the side portions of the cross members that provide the connection between the center portion and the side members, and further including the side members and the connectors that fixedly connect the side members to the cross members and which releasably connect the side member ends for mounting and de-mounting the tire chain to a tire.  
         [0009]     The criteria for this second major composition is again that it contain the necessary strength to withstand the stresses involved in securing the center tread portions of the cross members of the tire chains to the tires. Such stresses result from the hammering of the tread portion against the road surface which act in a variety of force vectors to twist and pull the chain free of the tire. A second criteria is that the composition accommodate the spacing provided, e.g., between the side wall of the tire and the vehicle structure and components of the vehicle. This spacing can be as small as about 8 millimeters and any thickness of the second composition that projects from the side wall more than about 8 millimeters may be unacceptable for use on certain ones of the mentioned vehicles having minimal clearance at the inner side walls of the vehicle tires.  
         [0010]     In a preferred embodiment, the type of tire chain that is adapted to provide the low interference fit is a cable type tire chain such as described in U.S. Pat. No. 5,236,025. Such chains consist of side members and cross members. The cross members are provided with at least one and preferably two sets of overwrapping spring segments that facilitate the gripping action of the tire to the road surface. The cross members extend across the tread of the tire in circumferentially spaced relation and the opposing ends are connected by connectors to side members (also cable type), which encircle the side wall of the tire at each side of the tire.  
         [0011]     To mount the tire chain to the tire, the side members are split apart at strategic positions and connectors releasably connect the split apart ends. Thus, the chain, with the connectors disconnected, can be laid out on the ground and slid into position at the inner side of the tire. The outer side member has a middle split with connectors and the ends of the middle split can be moved to the outer side, front and back, and then connected at the outer side of the tire. The portion of the tire engaging the ground is located in the spacing between cross members. The chain is thereby laid out under the tire and extended to the front and rear of the tire. The chain length at the front and rear of the tire can then be wrapped onto the tire and the inner side member ends and then the outer side member ends connected together. Mounting is completed by drawing the chain to the outer side to tighten the inner side member against the inner wall of the tire and an elastic tightener is applied to the outer side member to maintain tightness. Alternatively, and as will be more fully described, the outer side member is designed to be tightened against the side wall and avoid the need for a separate tightener.  
         [0012]     Whereas the described arrangement is not new, the problem is that there are multiple connectors that reside at the inner side wall of the tire. The cable and spring segments themselves provide a thickness of about 9 millimeters and the typical connector connecting the cross member to the side member (as well as the connection of the side member ends) is at least that much and greater. With the reduced clearance, it is desired to reduce the thickness of any part of the tire chain that resides along the sidewall, e.g. to 8 millimeters or less, but without sacrificing the integrity of the chain.  
         [0013]     A series of design developments cooperatively provide the ability to produce a preferred embodiment of a low-cost tire chain that satisfies the low clearance requirements and retains or improves strength/wear resistance. The thickness of the cable and spring segments that extend in part radially along the inner wall of the tire is first resolved. Whereas the spring segments do not contribute to the strength (they provide improved gripping) and whereas the gripping is not required at the side walls, the spring segments are removed from the cross members at the side wall areas and bushings are crimped onto the cable at the juncture where the side walls merge with the lateral portion of the tire tread to prevent migration of the spring segments from the tread area of the tire onto the inner side wall. Thus, the portion of the cross members that extend axially down along the tire&#39;s side wall is the cable thickness only which provides the same strength but is about 3.2 millimeters in thickness.  
         [0014]     The next area of concern is the connection of the cross member cable to the side member cable which is not wrapped and which is conventionally about 3.2 millimeters thick. A connector assembled onto the end of a cable will presumably increase the thickness at the connection by more than double. The present invention uniquely provides for this connection using radius bands. A sheet or plate of metal, e.g. 1.6 ml thick, is configured to have adjacent over and under bands of metal. The cable of both end and side members is threaded through the bands which are then crimped onto the cable, forcing the cable into a slight wave configuration. The overall width generated by the connector as crimped onto the cables is about 5 millimeters.  
         [0015]     The releasable male and female connectors for releasably connecting the opposing side member ends each have radius bands that are also crimped onto the respective cable ends. One of the connectors is provided with a key slot and the other a mated button that fits the key slot. As connected, they, too, provide a total thickness when connected that is less than or about 5 millimeters.  
         [0016]     The invention will be more fully understood and appreciated upon reference to the following detailed description and accompanying drawings. Whereas a preferred embodiment is disclosed above, there are numerous additional embodiments and variations thereto that are encompassed by this invention. Certain of the variations and additional embodiments will be illustrated and discussed in the following detailed description.  
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a schematic pictorial representation of a tire and a tire chain of the present invention mounted to the tire;  
         [0018]      FIG. 1A  is a section view as taken on view lines  1 A- 1 A of  FIG. 1  but further including a portion of the vehicle structure illustrating a restricted spacing for the tire chain;  
         [0019]      FIG. 2  and  2 A are full and partial (enlarged) plan views of the tire chain of  FIG. 1  but laid flat as when prior to fitting the chain to a tire;  
         [0020]      FIGS. 3 and 3 A are views of two connector types used for connecting the cross members to a side member such as shown in  FIG. 1 ;  
         [0021]      FIGS. 4, 4A  and  4 B illustrate a connector for connecting cross members to a side member and for releasably connecting opposed side member ends as shown also in  FIG. 1 ;  
         [0022]      FIG. 5  is a plan view of a releasable connector for connecting opposed ends of an outer side member, also shown in  FIG. 2  and  2 A;  
         [0023]      FIG. 6  is a section view as taken on view line  6 - 6  of  FIG. 5 ; and  
         [0024]      FIGS. 7-19  are additional embodiments and variations of the invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]     Reference is made to  FIGS. 1, 1A ,  2  and  2 A which illustrate a preferred embodiment of a tire chain of the present invention, mounted on a tire  22  as shown in  FIG. 1  and  1 A, and in laid out in plan view as shown in  FIGS. 2 and 2 A, i.e., prior to assembly onto the tire as in  FIGS. 1 and 1 A. The tire chain of this preferred embodiment includes an inner side member  10 , an outer side member  12  and cross members  20 . As shown in  FIG. 1  and  1 A, the inner side member  10  is fitted to the side wall  14  of the tire  22  as located at the inside of a wheel well defined by fender  18 . The side wall  14  is closely adjacent to a non-rotating portion schematically represented at reference  16  as an inner wall of the fender but the reader will appreciate this minimal clearance will more likely be determined by a portion of a brake, suspension and other vehicle components or structures.  
         [0026]     An object of the invention is to maintain the safety and durability desired of a conventional tire chain but also enabling the tire chain components to fit the restricted space between the vehicle component  16  and the tire side wall  14  as shown in  FIG. 1A . The primary components of the tire chain are the inner and outer side members  10  and  12  and the cross members  20  that extend between the cross members. As particularly illustrated in  FIGS. 2 and 2 A (but see also  FIG. 1 ), the cross members  20  are connected to the side members  10  and  12  by connectors  24 . Additionally, in order to assemble and disassemble the tire chain to the tire, releasable connectors are provided both for the inner side members  10  (connector components  26 ,  26 ′) and for the outer side members (connector components  28 ,  28 ′).  
         [0027]     Briefly, when assembling the tire chain on a tire, connectors  28 ,  28 ′ intermediate the end connectors  28 ,  28 ′, as viewed in  FIG. 2A , are disconnected to allow the tire chain to be laid on the roadway at the inner side of the tire and then the center connectors are brought around the front and back side of the portion of the tire engaging the ground. The two connectors  26 ,  26 ′ at the inner side of the tire are first pulled up to circumscribe the inner wall  14  of the tire to meet at or near the top side of the tire where connectors  26  and  26 ′ are connected. See  FIG. 1 . The outer connectors  28  and  28 ′ (opposing connectors  26 ,  26 ′) are then similarly brought up at the front and rear of the tire to circumscribe the outer side wall of the tire and they are connected. The intermediate connectors  28 ,  28 ′ (shown connected in  FIG. 2A ) are then connected. A tensioning cord is typically applied to take up any remaining slack. However, applicant proposes a newly developed concept whereby the outer side member is configured to replace the tensioning cord and is disclosed separately herein in a later section. The tensioning cord is not illustrated.  
         [0028]     With reference to  FIGS. 1 and 1 A, it will be noted that the primary areas of concern is that portion of the tire chain that rotates with the tire and directly adjacent the non-rotating vehicle structure  16 . The chain components particularly affected by this limited spacing are: a) the portion of the cross members  20 ., i.e.,  20 ′, that extend from the tread portion  30  of the tire along the side wall; the inner side member  10 ; the connectors  24  connecting the cross member portion  20 ′ to the inner side member; and the releasable connector components  26 ,  26 ′.  
         [0029]     It is desirable that these components fit closely against the tire side wall  14  and not project laterally from the side wall so as to engage the non-rotating portion  16 . It is also desirable that the strength of these components not be compromised. For the example herein discussed, it is considered desirable to maintain the lateral dimension of the affected components as projected from the side  14  of the tire to no more than about 6 millimeters.  
         [0030]     Reference is first made to the cross members  20  as shown in  FIGS. 1, 1A  and  2 A. Cross member  20  is typically comprised of a cable core  20 ′ with spring segments  32  surrounding the core. The spring segments  32  provide enhanced gripping on a roadway covered with snow or ice. The springs add dimension to the cable core but without adding strength. As the side wall is not involved in the traction, the springs are superfluous to the cross member  20 ′ but undesirably, in the present context, adds circumferential dimension. Accordingly, the springs  32  are removed from cable portion  20 ′ at the inner side of the tire and a bushing  33  is affixed to the cable  20 ′ at about the juncture  11  of the side wall  14  and tread  30  of the tire (see  FIG. 2A ) to prevent migration of the spring segments  32  from their position on the tread and onto the side wall  14 . This reduces the width or lateral dimension of the cross member  20  at the side wall to the thickness of the cable  20 ′ only, e.g., 3.2 millimeters.  
         [0031]     Reference is now made to  FIGS. 2A, 3  and  3 A which illustrate alternate types of connectors for securing the cable portions  20 ′ of the cross member  20  to the side member  10  which is also a cable only, e.g., having 3.2 mil thickness.  
         [0032]     The connectors  24 ,  24 ′ of  FIGS. 3, 3A  are of formed metal sheet of about 1.6 mil thickness. As illustrated the connector  24 ,  24 ′ include a base portion  34 ,  34 ′ and diverging fingers  36 . The base portion  34 ,  34 ′ clamps onto the side member  10  (see  FIG. 2A ) whereas the fingers  36  clamp onto the core portion  20 ′ of the cross members  20 . The metal of the connectors  24 ,  24 ′ is formed into bowed “radius bands”  38 ,  38 ′ that alternate between under and over bands. It will be appreciated that each connector portion includes 3 to 5 radius bands and are indicated by reference number  38  or  38 ′. Whereas  FIGS. 3 and 3 A do not show the cable core  20 ′ clamped to the connector by the radius bands, such is shown for the connector of  FIGS. 5 and 6  which are referred to here only to provide an understanding of the manner of securement of the radius bands  38  to the cable core/side member  10 . As shown in  FIGS. 5 and 6 , the side member  12  (same as cable core  20 ′) is threaded over and under at least  3  of the bands, and then the bands are pressed or crimped together to lock the cable core to the connector. (The outer most band may remain uncrimped to avoid what otherwise could be a tight outer edge of the metal of the connector digging into the cable core.) In the process, as noted in  FIG. 6 , the cross member  12  is compressed into a wave form that accomplishes secure gripping as well as reducing the thickness of the combination of cable core and connection. Whereas the radius fingers are both above and below the cable core, the combined thickness is but the thickness of the cable core and a single thickness of the sheet metal, e.g., 3.2 mil. plus 1.6 mil, or about 5 millimeters. thickness. Again, this arrangement of connection as shown in  FIGS. 5 and 6  apply to all of the connectors where is provided by radius bands.  
         [0033]     Referring to  FIGS. 1, 2 ,  2 A and  3 , it will be noted that the fingers  36  of connectors  24  are angled to accommodate the angled direction of the cables as they cross from one side member to the other. Such angling of the fingers is beneficial as the cable is less likely to become aligned with and seat into a tread groove with consequential wearing problems.  
         [0034]     Reference is now made to the releasable connectors  26 ,  26 ′ and  28 ,  28 ′ as shown in  FIGS. 4, 5  and  6 . Like connectors  24  of  FIGS. 1, 2 ,  2 A and  3 , the releasable connector  26 ,  26 ′ of  FIG. 4  are connected to the cable cores  20 ′ by the crimping of radius bands  38 . As explained, the side member  10  is the same as cable core  20 ′ and similarly are crimped onto the connectors  26 ,  26 ′ using radius bands  38 . Connectors  28 ,  28 ′ of  FIGS. 5 and 6  are connected to side member  12  also using radius bands  38  for convenience of manufacturing rather than for space consideration. However, it will be understood that two sides of the tire chain could be similarly structured to provide reversibility of the tire chain and/or to accommodate a tight spacing at the outer side of the wheel well.  
         [0035]     In both the structures of connectors  26 ,  26 ′ and  28 ,  28 ′, the one part of the connector portion ( 26 ′ and  28 ′) is provided with female key slots  40  and the opposite portion ( 26  and  28 ) is provided with male flat-headed button connectors  42 . As can be particularly seen in  FIG. 6 , the connectors  26 ,  26 ′ and  28 ,  28 ′ provide no greater thickness than the thickness of the cable and radius bands.  
         [0036]     As will be apparent, there is no sacrifice in the strength of the tire chain while reducing the lateral projection of the tire chain to a minimum as desirable for avoiding interference. The radius bands are proven to provide the secure attachment required and the metal connectors produce the necessary strength. The maximum lateral projections from the tire wall is the singular width of the sheet metal plus the thickness of the cable core.  
         [0037]     A further improvement is to the manner of connecting the button connectors illustrated in  FIGS. 4A and 4B . The button and key slot are so arranged relative to the bumps provided by the bowing of the radius bands  38  whereby connection/disconnection requires angular positioning as seen in  FIG. 4A . Following seating of the button  42  in the slot as seen in  FIG. 4A , the components can be oriented to an aligned position as shown in  FIG. 4B . Disconnection requires similar angular orientation of the components  26 ,  26 ′. Such inhibits the likelihood of accidental disconnection.  
         [0038]     Whereas the alternative embodiment of  FIG. 3A  has not been explained in detail, it will be appreciated that the opened radius bands  38 ′ allow for easier connection to the side member  10 , i.e., the side member does not have to be extended through the connector base  34 ′. The opened bands allow the cable portion/side member to be inserted under the open bands and the bands  38 ′ closed or crimped onto the side member.  
         [0039]     Numerous other modifications will become apparent to those skilled in the art and the invention is intended to encompass all such variations as may be determined by the broad interpretation of the elements of the claims appended hereto. For illustration purposes, examples of such other embodiments are illustrated and briefly described hereafter.  
         [0040]      FIGS. 7 and 7 A disclose a further embodiment of the invention. Cross member  120  is doubled in length and folded to provide a loop portion  144  at the inner side of the tire. A modified connector  146  is folded over and crimped onto loop portion  144  and inner side member  110 . Bushings  133 , as in the embodiment of  FIGS. 1 and 2 , prevent migration of the spring segments  132  onto the loop portion  144 , i.e., that portion of the cross members that fit against the side wall of a tire.  
         [0041]      FIG. 8  is a further embodiment and particularly emphasizes the differing objectives of the two functional compositions. The outer side member  212  (where thickness is not as likely a problem) is comprised of chain lengths as is the major portion of the cross members  220 . That segment of the cross member  220 ′, intended to extend down the side wall at the inner side of the tire, is provided with the smaller dimensioned cable which is connected to the chain links via connectors  221  (the connectors utilizing the radius band type of connection as previously described). As in the embodiment of  FIGS. 1 and 2 , the inner side member  210  is cable also as disclosed for the embodiment of  FIGS. 1 and 2 .  
         [0042]      FIGS. 9, 10 ,  11  and  12  are all variations of the  FIG. 8  embodiment, i.e., combining cable and chain links as the cross members, with chain applied where gripping is desired, i.e., extended across a tire tread, cable applied where the smaller dimension is desired, e.g., at the inner side wall. Further, the outer side member is chain and the inner side member is cable.  
         [0043]      FIGS. 13 and 14  are directed to further variations. The V-shaped cross members of  FIG. 13  are the described chain and cable combination as previously illustrated and described, but including connecting segments  52 ,  54  substantially at the juncture  11  of the tire and where the chain and cable intercept. As illustrated, segment  52  is chain links, and  54  is cable having spring segments as described for the cross members of  FIG. 1 , etc.  FIGS. 14 and 15  can be considered an H-shape with an extended length of cable connected at both ends to the inner cable side member via radius band connections, the intermediate cable being looped through a pair of cross member chain lengths as shown. The cable length extended between the chain links may be only cable or fitted with spring segments as also illustrated.  
         [0044]      FIG. 15  is similar to  FIG. 14  but with the cross members forming A-shapes and the connection between the cross members, in one case, provided by a further chain length.  
         [0045]      FIG. 16  illustrates a still further variation where pairs of cross members are centrally connected, i.e., mid way of the tread width, by short chain lengths  54 , or short spring segments/cable lengths  56 . The inner side member is cable and the cross members, as extended from the inner side member, is the described cable core, bushing and spring segments/cable core as described for the embodiment of  FIGS. 1 and 2 .  
         [0046]      FIG. 17  is a variation of the embodiment of  FIGS. 2 and 2 A with alternating spring segments  32  and composite members  50 .  
         [0047]      FIG. 17A  is a second variation of the embodiment of  FIGS. 2 and 2 A with alternating spring segments  32  and composite members  50 .  
         [0048]      FIG. 18  illustrates a further embodiment of the invention.  FIG. 19  is a side view of a portion as indicated. This embodiment utilizes a strap type configuration, e.g., of fabric reinforced rubber, to produce the cross members. The inner and outer side members are both cable as, e.g., described in  FIG. 2 . The center portion  44  that spans the tread is ribbed as illustrated in  FIG. 19 . That portion that extends down the inner side wall of the tire may be a thinner section  46  as permitted by the strap&#39;s width, i.e., to provide the desired strength and again as illustrated in  FIG. 19 , or it may again be a cable length  46  secured to the strap  44  by an embedded cable loop  60  as illustrated in the cut-away portion at the far left strap of  FIG. 18 .  
         [0049]     As well known and as previously indicated, once the tire chain was mounted on the tire, typically an elastomeric tensioner was applied to the outer side member. Such tensioner is considered necessary for tightening the tire chain but generates an additional part and further often extends across a hub portion of the tire and can mark the hub, which hubs are often considered an attractive feature of a vehicle, and such marking is undesired.  
         [0050]     To avoid such interference with the hub and to eliminate the extra part, a variation to the outer side member can be provided with tensioning mechanism to enable the side member to also produce the tightening or tensioning function.  
         [0051]     Referring to  FIGS. 20-22 , a tire  100  is shown having a tire chain mounted thereto. What is shown of the tire chain is an outer side member  102  and cross members  104  extended from the outer side members outwardly to the tread of the tire. The outer side member is preferably interconnected chain links as illustrated, e.g., in  FIGS. 9-12 . With further reference to  FIGS. 20-22 , the side member  102  can be shortened by providing an end of the side member with a slide ring  106  which is of sufficient size to allow an opposing end of the side member to be threaded through the ring and cinched back over the ring as illustrated in  FIG. 21 . The extreme end of the opposing end of the side member is secured to a lock member  108 , e.g., by a rivet  110 .  
         [0052]     As noted from  FIG. 22 , the lock member has a through passage  112  and the side member chain is extended through the through passage  112  as illustrated. By simply pulling manually on the lock member  108  in the direction of arrow  114 , the side member  102  is shortened and the entire tire chain is pulled inwardly toward the center of the tire.  
         [0053]     When sufficiently tightened, a lock bar  116  of the lock member  108  is pivoted down onto the chain within the lock member and the hook portion  118  of the lock bar  116  hooks into a chain link preventing movement opposite to arrow  114 . The side member is thereby locked at the reduced length to retain the side member in the shortened/tensioned condition. It will be appreciated that one or more tensioning mechanisms as described above may be used.  
         [0054]     Persons skilled in the art will conceive of numerous further embodiments and variations thereto. Accordingly, the invention is not limited to the specific embodiments and variations herein, but is intended to encompass all such tire chains as may be considered to encompass the definition of the claims appended hereto.