BACKGROUND ART [002] Most vehicles are initially fitted with"all season"tires, which provide adequate traction in good driving conditions. However, adverse driving conditions are common especially during the winter season in northern climates. Although snow tires have been designed to enhance traction, the traction afforded by these tires is, in some instances, not enough. Snow and ice on road surfaces make them very slippery and as a result, drivers can often find themselves stuck. Unfortunately, once stuck, vehicle tires typically just spin requiring the vehicle to be towed to extricate it from its stuck position. Similar situations can of course arise when vehicles are driven off- road on unpaved surfaces in wet conditions.

[003] To deal with the above situations, removable traction devices for vehicle tires have been considered. For example, U. S. Patent No. 2,530,108 to Whichard, Sr. et al discloses a traction device including a resilient U-shaped holder made of spring stock. The U-shaped holder can be secured to a vehicle tire by spreading the arms of the U-shaped holder apart and subsequently releasing the arms so that they grip the tire. The arms are spring biased inwardly to ensure contact with the sidewalls of the tire.

[004] U. S. Patent No. 2,871,903 to Minutilla discloses a U-shaped traction device for motor vehicle tires. The traction device includes a number of layers of spring steel of different lengths that are secured together by fasteners. The layers define a base and upwardly extending arms. A wear plate having a tread pattern thereon is fastened to the outer layer of spring steel.

[005] U. S. Patent No. 4,747,437 to Magee discloses a resilient traction device having a U-shaped cross-section defining a wide base and a pair of narrower, upwardly curved arms. The traction device can be secured to a vehicle tire by spreading the arms of the traction device apart and subsequently releasing the arms so that they grip the sidewalls of the tire. The arms have a convex bottom section and an

inwardly converging top section. When the weight of a vehicle bears on the base, the resultant force is transmitted to the sidewalls of the tire via the curved segments of the arms. The wide base and the convex bottom sections of the arms intensifies the gripping action.

[006] U. S. Patent No. 3,291, 180 to Gellman discloses a rigid clamp-type traction device including a U-shaped frame having two spaced upright leg portions movable with respect to each other. Transverse sections are integral with the leg portions and are disposed across the tire tread. A cam-type gripping arrangement is mounted on opposed surfaces of each leg portion. A locking mechanism releasably joins the transverse sections.

[007] Alternative traction devices for vehicle tires have also been considered and are disclosed in the following U. S. Patents: U. S. Patent No. 2,518,170 to Otis; U. S. Patent No. 2,525,367 to Miller; U. S. Patent No. 2,808,094 to Marchionda; U. S. Patent No. 3,068,925 to Stephens; U. S. Patent No. 3,289,727 to Marks; U. S. Patent No. 3,473,592 to Marks; U. S. Patent No. 4,235,272 to Landsrath; and U. S. Patent No. 5,115,851 to Chiavatti.

[008] Although the above-identified references show traction devices to be releasably secured to a vehicle tire to improve traction, improved tire traction devices are desired. It is therefore an object of the present invention to provide a novel tire traction device.

DISCLOSURE OF THE INVENTION [009] According to one aspect of the present invention there is provided a tire traction device to be releasably secured to a vehicle tire comprising : a base pad having a ground engaging surface and a tire engaging surface, said ground engaging surface having a tread pattern thereon, said base pad decreasing in thickness in at least one direction to define a thin leading edge;

a pair of side pads on opposite sides of said base pad to engage opposite sides of a tire ; and a coupling mechanism coupling the side pads to the base pad, said coupling mechanism being adjustable to bring the side pads into engagement with the sides of a tire when the tire engaging surface overlies a portion of the tread of a tire thereby to secure the tire traction device to said tire.

[010] In the preferred embodiment, the base pad decreases in thickness in both directions to define thin leading and trailing edges. The tire engaging surface has projections formed thereon to engage frictionally the tread of a tire. The tread pattern includes a plurality of rows of spaced projections. The spaced projections are generally conical and the projections in adjacent rows are staggered.

[011] It is also preferred that the side pads are curved to follow the side profile of a loaded tire and that the base pad is generally arcuate to follow the curvature of the tire tread. Each side pad has an inner surface with spaced projections thereon. The spaced projections frictionally engage the sides of a tire.

[012] In one embodiment, straps are secured to each side pad. The straps accommodate mating portions of a buckle. The straps are passed through the rim of the tire and the buckle portions are brought into mating engagement to secure further the tire traction device to the tire.

[013] According to another aspect of the present invention there is provided a tire traction device to be releasably secured to a vehicle tire comprising: a base pad having a ground engaging surface and a tire engaging surface, said ground engaging surface having a tread pattern thereon and said tire engaging surface having projections thereon, said base pad decreasing in thickness in opposite directions to define thin leading and trailing edges; a pair of side pads on opposite sides of said base pad to engage opposite sides of a tire; and at least one bolt assembly passing through aligned bores in said side pads and said base pad, said at least one bolt assembly being adjustable to bring the side pads into frictional engagement with the sides of a tire when the tire engaging surface overlies a portion of the tread of a tire thereby to secure the tire traction device to said tire.

[014] According to yet another aspect of the present invention there is provided a kit for tire traction comprising: a pair of tire traction devices to be releasably secured to vehicle tires, each of said tire traction devices including: a base pad having a ground engaging surface and a tire engaging surface, said ground engaging surface having a tread pattern thereon, said base pad decreasing in thickness in at least one direction to define a thin leading edge; a pair of side pads on opposite sides of said base pad to engage opposite sides of a tire; and a coupling mechanism coupling the side pads to the base pad, said coupling mechanism being adjustable to bring the side pads into engagement with the sides of a tire when the tire engaging surface overlies a portion of the tread of a tire to secure the tire traction device to said tire.

[015] The present invention provides advantages in that the tire traction device can be quickly and easily installed on a vehicle tire to provide enhanced traction on slick surfaces to enable a stuck vehicle to extricate itself. Once extricated, the tire traction device can be removed from the vehicle tire just as easily as it is installed and can be conveniently carried in the trunk or other storage compartment of the vehicle. The present invention also provides advantages in that the tire traction device can fit a broad range of tires.

BRIEF DESCRIPTION OF THE DRAWINGS [016] Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of a tire traction device in accordance with the present invention; Figure 2 is side elevational view of the tire traction device of Figure 1; Figure 3 is an exploded front elevational view of the tire traction device of Figure 1; Figure 4 is a perspective view of a base pad forming part of the tire traction device of Figure 1;

Figure 5 is a perspective view of a side pad forming part of the tire traction device of Figure 1; Figure 6 is a perspective view of a bolt assembly forming part of the tire traction device of Figure 1; Figure 7 is a perspective view of an alternative embodiment of a tire traction device in accordance with the present invention; and Figure 8 is another perspective view of the tire traction device of Figure 7.

BEST MODE FOR CARRYING OUT THE INVENTION [017] Turning now to Figures 1 to 6, a tire traction device in accordance with the present invention is shown and is generally indicated to by reference numeral 50.

The tire traction device 50 is formed of lightweight, resilient plastic material such as nylon to provide longevity and strength throughout a wide range of temperatures. It is understood by those skilled in the art that suitable materials that may be used to manufacture the tire traction device 50 include, but are not limited to, nylon, such as impact modified Nylon 6 or similar nylon brands, ABS/polycarbonate blends, high density polyethylene, reinforced ABS, Hytrel and a variety of urethanes. The tire traction device 50 is designed to be releasably secured to a vehicle tire to provide enhanced traction in adverse conditions. The device 50 can be manufactured in a variety of ways such as by high pressure thermoplastic injection or by compression molding.

[018] As can be seen, tire traction device 50 is generally U-shaped and includes a base pad 52, a pair of curved side pads 54 on opposite sides of the base pad 52 and a pair of adjustable bolt assemblies 58 coupling the side pads 54 to the base pad 52.

[019] Turning now to Figures 2 and 4, the base pad 52 is better illustrated.

As can be seen, the base pad 52 is arcuate when viewed in side elevation. The curvature of the base pad 52 is selected so that it generally follows the curvature of a conventional vehicle tire. The base pad 52 also decreases in thickness towards its ends to present thin leading and trailing edges 60 and 62 respectively and includes a ground contacting surface 64 and a tire tread contacting surface 66. A tread pattern

generally identified by reference numeral 68 is provided on the ground contacting surface 64. The tread pattern 68 contacts the ground surface when the tire traction device 50 is secured to a vehicle tire as will be described. In this embodiment, the tread pattern 68 includes a plurality of rows of thick, generally conical projections 70.

The projections 70 in adjacent rows are staggered. The tire tread contacting surface 66 has a plurality of rows of small, generally conical projections 72 formed thereon to engage the tread portion of a tire when the tire traction device 50 is secured to a vehicle tire. The projections 72 in adjacent rows are also staggered. A pair of laterally spaced transverse bores 74 extend through the base pad 52 and accommodate the bolt assemblies 58.

[020] Turning now to Figures 3 and 5, side pads 54 are better illustrated. As can be seen, each side pad 54 is curved and includes a smooth outer surface 80. The curvature of each side pad 54 is selected so that the shape of the side pad generally conforms to the side profile of a loaded tire. The inner surface 82 of each side pad has a plurality of small, generally conical projections 84 formed thereon. The projections 84 frictionally engage the side of a tire when the tire traction device 50 is secured to a vehicle tire. Spaced bores 86 that align with the bores 74 in the base pad 52 are provided through each side pad 54 and also accommodate the bolt assemblies 58.

[021] Each bolt assembly 58 includes a bolt 90 having a long threaded rod 92 with a cap 94 at one end, an internally threaded sleeve 96, and a bolt 98 having a short threaded rod 100 with a cap 102 at one end. The bolts 90 and 98 threadably engage opposite ends of the sleeve 96. Typically, the bolt 98 is fully threaded into the sleeve 96 and the bolt 92 is adjusted with respect to the sleeve 96 during use of the tire traction device. Removal of the bolt 98 from the sleeve 96 allows the tire traction device 50 to be quickly disassembled. Withdrawl of the bolt 90 from the sleeve 96 allows the side pads 54 to be further separated allowing the tire traction device 50 to be used on wider tires. Washers (not shown) act between the caps 94 and 102 and the outer surfaces 80 of the side pads 54.

[022] In use, the tire traction device 50 is installed on a vehicle tire by placing the base pad 52 on the tire so that the tire tread contacting surface 66 rests on the tread of the tire with the side pads 54 being positioned on opposite sides of the

tire. The arcuate shape of the base pad 52 ensures that the base pad follows the curvature of the tire. A wrench or other suitable tool is then used to tighten the bolts 90 so that they advance into the sleeves 96 thereby to bring the side pads 54 into contact with the sides of the tire so that the conical projections 84 on the inner surfaces 82 frictionally engage the sides of the tire. The curved nature of the side pads 54 allows the side pads to extend over the bulge in the tire. In this manner, the side pads 54 secure the tire traction device 50 to the tire. At this point, the tire can be rotated.

[023] As the tire is rotated to bring the tire traction device 50 toward the ground surface, the thin leading edge 60 is pinched between the tire tread and the ground surface. The large conical projections 70 break up the ground surface under the tire allowing the broken ground surface to be pushed away from beneath the tire.

As the tire further rotates, the tire traction device 50 is brought underneath the tire by virtue of the frictional engagement between the tire tread and the small conical projections 84 on the tire tread contacting surface 66. With the large conical projections 70 positioned beneath the tire, added traction is provided. The projections 70 typically inhibit further spinning of the tire allowing the vehicle to advance.

[024] Since the side pads 54 are shaped to conform generally to the side profile of a loaded tire, when the tire traction device 50 is pulled under the tire, the side pads only marginally deflect. Once the tire traction device 50 passes from beneath the tire, the side pads 54 relax and return to their unloaded condition. As a result, the side pads 54 can remain small and lightweight since they are not required to take significant loading as the tire traction device 50 is pulled beneath the tire.

[025] Turning now to Figures 7 and 8, an alternative embodiment of a tire traction device in accordance with the present invention is shown and is generally identified by reference number 150. For ease of reference, like reference numerals will be used to identify like components of the previous embodiment with a"100" added for clarity.

[026] The tire traction device 150 is very similar to that of the previous embodiment and includes a base pad 152, a pair of curved side pads 154 on opposite sides of the base pad 152 and bolt assemblies 158 coupling the side pads 154 to the base pad.

[027] Unlike the previous embodiment, in this embodiment the tire traction device 150 includes four bolt assemblies 158 with each bolt assembly including an elongate bolt 190 and a nut 200. Each nut 200 is accommodated by a slot formed in the ground engaging surface 164 of the base pad 152. The slots intersect the transverse bores provided through the base pad to allow the bolts 190 to engage threadably the nuts 200.

[028] Also, unlike the previous embodiment, each side pad 154 has a pair of vertically spaced slots 210 and 212 formed therein. A strap 214 passes through the slots in each side pad so that a portion of the strap runs along the outer surface 180 of its associated side pad. One end of each strap 214 is bunched to inhibit the strap from being pulled through the slot 210. The straps 214 also accommodate mating portions of a snap buckle 216.

[029] In use, the tire traction device 150 is secured to a tire in a very similar manner to that of the previous embodiment by properly positioning the tire traction device with respect to the tire and tightening the bolts 190 so that they pass through the nuts 200 and advance into the bores. In this manner the side pads 154 are brought into engagement with the sides of the tire.

[030] The straps 214 are then passed through the rim of the tire and the portions of the snap buckle 216 are brought into mating engagement. As will be appreciated, the straps 214 and buckle 216 provide further means to secure the tire traction device 150 to the tire and inhibit its accidental separation from the tire during use.

[031] As will be appreciated, the tire traction device 50,150 can be secured to a tire easily to enhance traction and inhibit spinning of the vehicle tire in adverse conditions. Since the tire traction device is lightweight, the tire traction device is simple in design, inexpensive to manufacture and remains on a rotating tire without requiring a large clamping force.

[032] The tire traction device 50,150 is preferably sold in pairs as a kit. The kit includes a carrying case to hold the tire traction devices and a tool to allow the bolts to be conveniently tightening and loosened. This enables the kit to be easily carried in the trunk of a vehicle. When a vehicle gets stuck on a road surface due to snow, ice, mud or other reason, tire traction devices 50,150 can be installed on a pair

of driven tires quickly and easily in a matter of seconds in the manner described above. As the tire traction devices 50,150 rotate with the driven tires, the projections 70 provide increased traction which is transferred back to the tires. Once the driven wheels have been freed, the tire traction devices 50,150 can be quickly and easily removed from the vehicle tires.

[033] Although the projections 70 as shown are basically the same size, if desired, to minimize the transition from the tire tread to the tread pattern 68, the projections 70 can progressively increase in height in a direction away from the thin leading edge 60. Also, as will be appreciated, alternative tread patterns and projection patterns can be used provided adequate frictional engagement is achieved.

[034] Although a preferred embodiments of the present invention has been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.