Abstract:
The present disclosure concerns an emergency traction device that may be easily and securely fitted on vehicles having tires of different diameters and widths. A single winch sizes and secures the traction device for the proper tire diameter and then for the proper tire width. Traction can be further enhanced with members that substantially circumscribe the tire. Operation of the traction device can be enhanced by providing nonreversible gearing for operating the winch.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority based on U.S. Pat. No. 6,053,227, filed Mar. 1, 1999, and claims the benefit of the earlier filing date of U.S. Provisional Application 60/158,371, filed Oct. 12, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention concerns a traction device for vehicles having at least one ground engaging tire. In particular, the invention is directed to an emergency traction device that is readily fitted to tires of various diameters and widths. Additionally, the present invention is directed to an enhanced emergency traction device that substantially circumscribes a tire. 
     Known traction devices include snow tires, studded tires, and tire chains. The use of snow or studded tires requires that the vehicle operator anticipate the occurrence of inclement weather and replace the ordinary tires with the snow or studded tires. Consequently, two sets of tires are required which must either be alternately mounted on one set of vehicle wheels, or a second set of wheels must be obtained. Disadvantages of snow or studded tires include the cost of changing multiple set of wheels and/or tires, and the inability to react to unexpected weather. 
     Tire chains are commonly installed on the ordinary tires of a vehicle to enable an operator to react to, rather than anticipate, inclement whether. The disadvantages of tire chains include the need to have a set of chains sized to fit the particular tires of a vehicle, and the possibility of a chain being “thrown-off” a rotating wheel damaging the vehicle body. 
     Further, tire chains are generally installed by driving a tire onto the chain and subsequently linking the chain around the circumference of the tire. In the event the vehicle is already stuck, i.e. the tire spins without gaining traction, it is not possible to install the chains which could free the vehicle without elevating the tire off the ground. 
     U.S. Pat. No. 5,735,980 to Robeson discloses an emergency traction device in which the mechanisms for fitting the device to the diameter and width of the wheel each include a separate winch. 
     Other types of device intended to be attached to the tires and/or wheels of vehicles for the purpose of improving traction are described in the United States Patents to Laub U.S. Pat. No. 5,513,684, Metraux U.S. Pat. No. 5,254,187, Zelent U.S. Pat. No. 4,974,653, Parker, III U.S. Pat. No. 4,886,100, McDonough U.S. Pat. No. 4,862,936, Regensburger U.S. Pat. No. 4,209,049, Hyggen U.S. Pat. No. 4,122,880 and U.S. Pat. No. 3,891,018, Welsh U.S. Pat. No. 4,098,314, Gomez U.S. Pat. No. 3,847,196, Clark U.S. Pat. No. 3,736,970, Scott U.S. Pat. No. 3,249,143, Bopst III U.S. Pat. No. 3,053,302, Hayes U.S. Pat. No. 2,981,303, Binegar U.S. Pat. No. 2,910,105, Schroen U.S. Pat. No. 2,640,522, Pindjak U.S. Pat. No. 2,598,298, and Edwards U.S. Pat. No. 2,423,759. In general, these patents disclose traction devices having a plurality of arms extending outward toward the tread surface of the tire. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an emergency traction device for attachment to a vehicle tire that is conveniently stored, easily adapted to tires of different diameters and widths, and is uniformly and securely installed. 
     Another object of the present invention is to provide an emergency traction device that may be readily installed and removed under any circumstances and terrain conditions. 
     Yet another object of the present invention is to provide an emergency traction device which is immediately transferable between alternate vehicles having different size tires. 
     A further object of the present invention is to provide an emergency traction device in which a single mechanism is used for fitting the device first to the diameter and then to the width of the wheel. 
     Yet a further object of the present invention is to provide an emergency traction device including additional traction devices overlying portions of the tread around a majority of a tire&#39;s circumference. 
     These objects, as well as additional objects and advantages of the present invention that will be apparent from the following description, are achieved according to a traction device for attachment with respect to a tire rotating on an axis, wherein the tire has a terrain engaging surface connecting a pair of sidewalls. The traction device comprises a plurality of arms adapted to extend radially with respect to the axis, each of the plurality of arms including a first section adapted to be radially extensible with respect the terrain engaging surface and a second section adapted to be extensible across the terrain engaging surface, each of the plurality of second sections being mounted at a radially outward end of a corresponding one of the plurality of first sections; a plurality of fingers adapted to engage one of the pair of sidewalls, each of the plurality of second sections extensibly connecting a corresponding one of the plurality of first sections and a corresponding one of the plurality of fingers; a winch including a cable drum and a plurality of cables, each of the plurality of cables extending from a corresponding one of the plurality of fingers, along corresponding ones of the first and second sections, to the cable drum; a plurality of first springs each expanding a corresponding one of the first sections; and a plurality of second springs each expanding a corresponding one of the second sections. Each of the first springs has a lower spring constant than a corresponding one of the plurality of second springs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a traction device according to a first preferred embodiment of the present invention shown in a collapsed state. 
     FIG. 2 is a front view of the traction device according to the first preferred embodiment of the present invention shown in an installed state. 
     FIG. 3 is a cross-section view taken along line III—III in FIG. 2 of a traction device according to the first preferred embodiment of the present invention shown in an installed state. 
     FIG. 4 is a front view similar to FIG. 2 showing a traction device according to a second preferred embodiment of the present invention. 
     FIG. 5 is a side view of the traction device according to the second preferred embodiment of the present invention. 
     FIG. 6 is a front view of a traction device according to a third preferred embodiment of the present invention shown in a collapsed state. 
     FIG. 7 is a front view of the traction device according to the third preferred embodiment of the present invention shown in an installed state. 
     FIG. 8 is a cross-section view taken along line VIII—VIII in FIG. 7 of a traction device according to the third preferred embodiment of the present invention shown in an installed state. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1-3, a traction device  10  is shown with respect to a tire  1 . Tire  1  includes a terrain engaging tread surface  2  and two sidewalls  3 , 4  connected by the tread  2  in a known arrangement. 
     Traction device  10  includes a plurality of arms  12 , 14 , 16 , 18  extending radially outward toward the tread  2 . Although four arms are illustrated, it is understood the present invention may include more or less than four arms. However, at least two arms must be present, and at least three arms or an even multiple of arms are preferable. 
     Each arm  12 , 14 , 16 , 18  includes a corresponding first extensible section  22 , 24 , 26 , 28  such that the traction device can be made to accommodate tires of varying diameters. Each first extensible section  22 , 24 , 26 , 28  includes a corresponding hollow rod  22 A, 24 A, 26 A, 28 A that is telescopically slidable within a corresponding tube  22 B, 24 B, 26 B, 28 B. Two telescopically related components A,B for each arm  12 , 14 , 16 , 18  are illustrated for the purposes of describing the present invention; however, more than two telescopic components are also possible. Preferably, the telescopic components A,B have cross-sections that prevent relative rotation along the length of the arms  12 , 14 , 16 , 18 . 
     Each first extensible section  22 , 24 , 26 , 28  further includes a corresponding first resilient biasing element  22 C, 24 C, 26 C, 28 C, e.g. a coil spring, causing relative expansion of the telescopic components A,B. According to a preferred embodiment of the present invention, the first resilient biasing elements  22 C, 24 C, 26 C, 28 C are enclosed by and extend within the telescopic components A,B of the first extensible sections  22 , 24 , 26 , 28 . 
     According to a preferred embodiment, a first group of the arms  12 , 16  are fixed at their radially proximal end to a first support plate  40 , and a second group of the arms  14 , 18  are fixed at their radially proximal end to a second support plate  42 . First and second support plates  40 , 42  are relatively pivotal about a central point substantially coincident with the axis of rotation  5  for the tire  1 . In the collapsed position of the traction device  10  (FIG.  1 ), first and second support plates  40 , 42  are relatively pivoted such that arms  12  and  14 , as well as arms  16  and  18 , are clustered together. After positioning the traction device  10  with respect to tire  1 , the first and second support plates  40 , 42  are relatively pivoted to equiangularly dispose the arms  12 , 14 , 16 , 18  around the tire rotation axis  5  (FIG.  2 ). A lock mechanism  44  maintains the relative position of the first and second support plates  40 , 42 . 
     A corresponding second extensible section  32 , 34 , 36 , 38  is mounted at the radially distal end of each arm  12 , 14 , 16 , 18 . According to a preferred embodiment of the present invention, each of the second extensible sections  32 , 34 , 36 , 38  is mounted with respect to their corresponding first extensible sections  22 , 24 , 26 , 28  by a hinge joint  30  that enables the traction device  10  to be further collapsed for storage. It is envisioned that one or more detents can be used to restrain pivoting about the hinge joint  30 . A first detent can be used to resist movement away from the folded position of the second extensible section with respect to the corresponding first extensible section, thereby eliminating the need to provide any other means, e.g., a strap, for holding the traction device  10  in its fully collapsed position. A second detent can be used to resist movement away from the perpendicularly extending arrangement of the second extensible section with respect to the corresponding first extensible section, thereby facilitating placing the traction device  10  around a tire. 
     Each second extensible section  32 , 34 , 36 , 38  includes a corresponding finger  52 , 54 , 56 , 58  engaging the inner sidewall  4  of the tire  1 . According to a preferred embodiment of the present invention, plates  53 , 55 , 57 , 59  may engage the outer sidewall  3  of the tire  1 . Each of the second extensible sections  32 , 34 , 36 , 38  is interposed between corresponding ones of the fingers  52 , 54 , 56 , 58  and either the first extensible sections  22 , 24 , 26 , 28  or the plates  53 , 55 , 57 , 59 . According to a preferred embodiment of the present invention, each second extensible section  32 , 34 , 36 , 38  includes a rod  32 A, 34 A, 36 A, 38 A telescopically related to a tube  32 B, 34 B, 36 B, 38 B such that each second extensible section  32 , 34 , 36 , 38  accommodates tires of varying widths. Although two telescopic components A,B for each second extensible section  32 , 34 , 36 , 38  are illustrated for the purposes of describing the present invention, more than two telescopic components are also possible. 
     Each second extensible section  32 , 34 , 36 , 38  further includes a second resilient biasing element  32 C, 34 C, 36 C, 38 C, e.g. a coil spring, causing relative expansion between corresponding ones of the fingers  52 , 54 , 56 , 58  and either the first extensible sections  52 , 54 , 56 , 58  or the plates  53 , 55 , 57 , 59 . According to a preferred embodiment of the present invention, the second resilient biasing elements  32 C, 34 C, 36 C, 38 C surround and extend along the second extensible sections  32 , 34 , 36 , 38  to enhance the relative traction between both the tire  1  and second extensible section  32 , 34 , 36 , 38 , as well as between second extensible section  32 , 34 , 36 , 38  and the terrain. Further, second resilient biasing elements  32 C, 34 C, 36 C, 38 C are readily replaceable after significant wear. 
     It is also possible for the second resilient biasing elements  32 C, 34 C, 36 C, 38 C to be enclosed by and extend within the telescopic components A,B of the second extensible sections  32 , 34 , 36 , 38 . In such a case, chain links or other traction enhancing projections may be provided on the exterior of the telescopic components A,B. 
     The first resilient biasing elements  22 C, 24 C, 26 C, 28 C are selected to have a lower spring constant than the second resilient biasing elements  32 C, 34 C, 36 C, 38 C. As it is used here, spring constant is defined as the force per unit of displacement within the elastic range of the resilient biasing elements C. 
     A winch  60  is supported by the first and/or second support plate  40 , 42  and includes a cable drum  62  that can be operably turned on a cable drum axis  64  by a crank (not shown). According to a preferred embodiment of the present invention, cable drum axis  64  is coaxial with tire rotation axis  5  in order to improve inertial balance of the traction device  10  as it rotates with the tire  1 . According to a preferred embodiment, the crank is removable to minimize the mass of the traction device  10 . 
     The first end of each of a plurality of cables  66  are attached to cable drum  62  and extend radially outward within the telescopic components A,B of the first extensible sections  22 , 24 , 26 , 28 . The second end of each of the plurality of cables  66  is secured with respect to a corresponding one of the fingers  52 , 54 , 56 , 58 . Rotation of cable drum  62  by the crank causes cables  66  to be wound on cable drum  62 , thereby contracting the first extensible sections  22 , 24 , 26 , 28  against the force of the first resilient biasing elements  22 C, 24 C, 26 C, 28 C. Rotation of the cable drum  62  further causes contracting of the second extensible sections  32 , 34 , 36 , 38  of the arms  12 , 14 , 16 , 18  against the force of second resilient biasing elements  32 C, 34 C, 36 C, 38 C. As it is used here, cable is defined as any flexible element such as wire, rope, cord, chain, etc. 
     Inasmuch as the first resilient biasing elements  22 C, 24 C, 26 C, 28 C have a lower spring force than the second resilient biasing elements  32 C, 34 C, 36 C, 38 C, the arms  12 , 14 , 16 , 18  are initially contracted along the first extensible sections  22 , 24 , 26 , 28 , i.e., radially with respect to the tire tread  2 , and are subsequently contracted along the second extensible sections  32 , 34 , 36 , 38 , i.e., across the tire tread  2 . That is to say, the traction device  10  is initially contracted to the diameter of the tire  1 . When the second extensible sections  32 , 34 , 36 , 38  are drawn inward into engagement with the tread  2 , radial contraction ceases. Thereafter, the traction device  10  is contracted to the width of the tire  1 . When the fingers  52 , 54 , 56 , 58  are drawn into firm engagement with the inner sidewall  4  of the tire  1 , width contraction ceases and the traction device  10  is securely held to the tire  1 . 
     Optionally, one or more detents may be used between the components A,B of the second extensible sections  32 , 34 , 36 , 38  to provide an initial resistance to contraction. Thus, the detents establish a minimum force the cables  66  must exert before the second extensible sections  32 , 34 , 36 , 38  begin contracting. This minimum force would not be exerted until the first extensible sections  22 , 24 , 26 , 28  are fully contracted. 
     A one-way ratchet mechanism  70  prevents loosening of the traction device  10  until a ratchet release lever  72  enables reverse rotation of the cable drum  62 , i.e., to unwind the cables  66  under the influence of the first and second resilient biasing elements C. Additionally, a governor mechanism may be used to regulate the speed of reverse rotation. 
     In addition to regulating the sequence of contraction, the first and second resilient biasing elements C compensate for deflection of the sidewalls  3 , 4  as portions of the tire  1  bulge due to contact of the tread  2  with the terrain. 
     Further modifications envisioned within the scope of the appended claims include securing the ratchet release lever  72  with a key lock (not shown) to prevent unauthorized release of traction device  10  from the tire  1 ; including cable stops (not shown) to limit movement of the cables  66  thereby facilitating replacement of the second resilient biasing elements  32 C, 34 C, 36 C, 38 C; including a mar resistant material on the sides of the support plates  20 , 22  confronting the tire  1  to prevent scuffing the wheel; including an anti-friction coating or lubricant at the interfaces between the components A,B of the first and second extensible sections  22 , 24 , 26 , 28 , 32 , 34 , 36 , 38 ; including an anti-friction coating or lubricant at the interfaces where the first and second resilient biasing elements C circumferentially touch the first and second extensible sections  22 , 24 , 26 , 28 , 32 , 34 , 36 , 38 ; and providing friction enhancing material at the interface between the fingers  52 , 54 , 56 , 58  and/or plates  53 , 55 , 57 , 59  with the sidewalls  3 , 4  of the tire  1 . 
     FIGS. 4 and 5 show a second preferred embodiment of the present invention wherein the preferred embodiment illustrated in FIGS. 1-3 is modified. Like reference numerals are used to designate like parts throughout the figures. 
     Each of the fingers  52 , 54 , 56 , 58  and the plates  53 , 55 , 57 , 59  include respective pairs of attachments A,B in FIGS. 4 and 5. Moreover, there may be a selection of additional possible attachments on each of the fingers  52 , 54 , 56 , 58  and the plates  53 , 55 , 57 , 59 . The attachments may be configured as holes, rings, or any other arrangement suitable for connection to respective elongated members  70 . 
     The elongated members  70  may include any flexible member capable of overlying the tire tread  2  between pairs of adjacent ones of the second extensible sections  32 , 34 , 36 , 38 . According to a most preferred embodiment of the present invention, the elongated members  70  are constructed of flexible metal wire, cable, or chain. Of course, additional materials and configurations are envisioned that are capable of extending between and being connected to the attachments, overlying a portion of the tire tread  2 , and providing enhanced traction for the portions of the tire&#39;s circumference between the second extensible sections  32 , 34 , 36 , 38 . 
     According to a most preferred embodiment of the present invention illustrated in FIG. 5, each elongated member  70  comprises a web of flexible members, e.g., metal cables, including a pair of side elements  72 , 74  extending circumferentially with respect to the tire  1  between pairs of adjacent ones of the second extensible sections  32 , 34 , 36 , 38 . At least one traction element  76  connects the side elements  72 , 74  and overlays the tire tread  2  to enhance traction between the tread  2  and the terrain. The traction element(s)  76  may be fixed with respect to the side elements  72 , 74  or may be movably mounted with respect to the side elements  72 , 74 . 
     It is envisioned that the elongated members  70  would be adjusted for different tire sizes by selecting an appropriate attachment  52 A, 52 B, 53 A, 53 B,etc., or by changing the length of the elongated members  70 , e.g., by resilient members or selecting a different length elongated member  70 . According to a preferred embodiment of the present invention, the number of times a traction element  76  is wrapped around the side elements  72 , 74  would eliminate slack in all of the elongated members  70 . 
     Of course, different configurations and combinations of elongated members  70  may be used. For example, a traction element  76  may be connected at a first end to an attachment on one of the fingers  52 , 54 , 56 , 58  and connected at a second end to an attachment on the plate  53 , 55 , 57 , 59  of an adjacent second extensible section  32 , 34 , 36 , 38 . Thus, a single traction element  76  would extend diagonally across the surface of the tread  2  between a pair of adjacent second extensible sections  32 , 34 , 36 , 38 . 
     FIGS. 6-8 show a third preferred embodiment of the present invention wherein the preferred embodiment illustrated in FIGS. 1-3 is modified. Again, like reference numerals are used to designate like parts throughout the figures. 
     According to the third preferred embodiment, the arms  12 , 16  are fixed at their radially proximal end to a first support plate  40 ′, and the arms  14 , 18  are fixed at their radially proximal end to a second support plate  42 ′. First and second support plates  40 ′, 42 ′ are relatively pivotal about a central point substantially coincident with the axis of rotation  5  for the tire  1 . The first support plate  40 ′ holds the arms  12 , 16  in a relatively parallel and offset relationship, and the second support plate  42 ′ also holds the arms  16 , 18  in a relatively parallel and offset relationship. In the collapsed position of the traction device  10  (FIG.  6 ), first and second support plates  40 ′, 42 ′ are relatively pivoted such that arms  12  and  18  aligned generally coaxially and parallel to arms  16  and  18 , which are aligned generally coaxially with one another. According to such an arrangement, the collapsed position of the traction device can be made more compact. After positioning the traction device  10  with respect to tire  1 , the first and second support plates  40 ′, 42 ′ are relatively pivoted to equiangularly dispose the arms  12 , 14 , 16 , 18  around the tire rotation axis  5  (FIG.  7 ). A lock mechanism  44  maintains the relative position of the first and second support plates  40 ′, 42 ′. 
     According to another aspect of the present invention, third preferred embodiment also shows an arrangement whereby the actuator for the cable drum  62  includes gearing that resists back driving, e.g., worm type gearing, in place of providing a one-way ratchet mechanism. Referring to FIG. 8, a pinion  70 ′ can be fixed for rotation with the cable drum  62  and can be operatively engaged by a worm  72 ′. Thus, rotation of the worm  72 ′ can drive the pinion  70 ′, and hence the cable drum  62 , but the cable drum could not back-drive the worm  72 ′ via the pinion  70 ′. Consequently, the traction device  10  can be contracted and expanded only in response to rotation of the worm. 
     In general, the worm  72 ′ is rotated about an axis that can be oriented perpendicular to the axis of the pinion  70 ′ and the cable drum  62 . It is envisioned that additional gearing could be connected to the worm for reorienting the worm drive to an axis parallel to or coaxial with the axis of the pinion  70 ′ and the cable drum  62 . For example, the worm  72 ′ can be driven via a face gear drive arrangement  73 . It is also envisioned that other types of back-driving resistant gearing could be used, e.g., strain-wave gearing or planetary gearing presenting a high gear ratio. It is further envisioned that the operator handle for the input to the gearing could be made integrally with the gearing, thereby precluding a separate handle being misplaced. 
     The foregoing description with reference to the figures of certain embodiments of the present invention is for illustrative purposes only. Various changes and modifications may be made within the spirit and scope of the appended claims.