Abstract:
A tire as provided with a circumferential portion for contacting a road surface. Edge segments thereof include studs and an inflatable chamber at the edge segment is inflated and deflated to extend and withdraw the edge segments for engagement and disengagement with the road surface.

Description:
This application is a continuation-in-part of application Ser. Nos. 09/284,557 filed Apr. 14, 1999, TRACTION DEVICE FOR VEHICLE WHEELS, which is a 371 of PCT/US 97/19454 filed Oct. 17, 1997; and a continuation of U.S. Pat. No. 08/909,302, filed Aug. 11, 1997 and now U.S. Pat. No. 5,810,451; and a continuation of U.S. Pat. No. 08/733,676, filed Oct. 17, 1996 and now U.S. Pat. No. 5,788,335. The disclosures of the above-referenced applications are included by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a traction device mounted to a vehicle wheel and is selectively convertible to road engaging and non-road engaging positions. 
     BACKGROUND OF THE INVENTION 
     This invention has particular application to dual wheels as exist on large trucks. However, as will be made clear, different forms of the invention can be applied to different types of vehicle wheels. 
     The invention is considered most applicable to large trucks driven by truck drivers that crisscross the country continuously throughout the year. Invariably a truck driver driving over mountain roads in the winter or even flat land roads in the Northern states, will on many occasions encounter road conditions where snow and/or ice is coated over the road surface. 
     The conventional wheel tire provides a road contacting surface area that frictionally grips a dry or even wet road surface providing steering and stopping control as well as propulsion over the road surface, but not when that surface is covered with ice and/or snow. The conventional tire surface has poor frictional gripping capability when riding on snow or ice. Whereas several explanations can be given depending on the condition of the ice/snow, what can and often does happen is that the surface of the snow or ice liquefies and forms a liquid film between the tires and underlying surface, thereby eliminating any opportunity for the tire to grip the surface frictionally. 
     An answer to this dilemma is to provide the tire with metal studs or chains. The studs are embedded in the tire permanently and the chains are designed to be placed on the tire when needed and removed when not needed. In both cases, the projecting metal bites down through the snow or ice (and liquid film) to generate the desired gripping action. Both have problems. Studded tires tear up a dry road surface, i.e., when not covered with snow or ice and most states have strict rules about using them. Most states ban their use except during the harsh winter months. Tire chains are designed to be put on and taken off. However, mounting the chains onto the vehicle tires is an unpleasant task even in ideal conditions which most often is not the case. Weather conditions are likely uncomfortably cold and blustery. Mounting the chains onto the tires can take upwards to an hour or more, and when parked alongside an ice-covered roadway and probably on a graded road, the driver is exposed to potential life threatening risks as other unchained vehicles attempt to pass. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention alleviates or obviates the problems associated with studded tires and the chaining of tires using a retractable studded tire having metal spike-like studs that project from the periphery of the tire and into the road surface or not. In a preferred embodiment, the studded tire is sandwiched between dual tires. The studded tire is designed to expand in circumference when inflated and to contract in circumference when deflated. This is achieved in part by the opposing walls of the dual tires that restrict lateral or axial expansion of the studded tire, thus forcing expansion circumferentially or radially. The expansion characteristics of the tire are designed to provide a circumferential size difference so that when deflated, the tire periphery (circumference) is retracted radially inwardly of the dual tires and when inflated is extended radially outwardly of the dual tires. 
     The studded tire of this preferred embodiment is not intended to carry the vehicle weight. Essentially the stud portions only of the tire protrude and are projected into the ice or snow, e.g., to a depth at which the dual tires still engage the road surface and support the load. The studs provide gripping action for propelling (or stopping) the vehicle as the studded tire rotates in unison with the dual tires, e.g., the studded tire is mounted on the same tire lugs and the expansion of the studded tire against the opposing side walls, rubber to rubber, resists rotative slippage of the studded tire relative to the load-bearing dual tires. 
     The studded tire is provided with valving and an air pressure source. The air pressure source may be operated automatically and remotely with direct connection between the air pressure source and the studded tire, or the air source may be an air-pressurized cannister that can be clamped to the valving for inflating the tire. Deflation is enabled, e.g., by a valve mechanism that simply exhausts the air from the studded tire to the atmosphere. 
     Ideally the inflation/deflation will be accomplished automatically from the truck cab even without the necessity of stopping the truck. The less sophisticated embodiment will allow the driver to stop the truck and in a matter of a few minutes inflate the several studded tires in a fraction of the time previously allotted for mounting tire chains. 
     An alterative embodiment that is contemplated will adapt the above expanding feature of an expandable studded tire to a single load-bearing tire. A special single tire is produced which provides conventional (non-studded) tread portions which are separated on the tire&#39;s periphery and a studded tire segment is provided between the separated tread portions. In a further alternative embodiment, the studded segments can be provided at the side edges of the tread. Air pressure is separately provided to the studded tire segment. In a preferred form of this alternative embodiment, the studded tire segment is inflated and deflated to expose and retract the studs. In a further embodiment, it is the conventional tread portions that are deflated and inflated to achieve the same result. 
     Other attempts have been made to provide a gripping member that can be left on the tires and would project into the road surface only when needed. An example of such an attempt is disclosed in E. Partin, U.S. Pat. No. 2,765,199. Among other differences, Partin does not teach the basic concept of using a studded tire that is expanded in the confining space between dual tires whereby the stationary tire walls induce circumferential expansion of the studded tire beyond the circumference of the dual tires. 
     Reference is made to the detailed description and drawings referred to therein for a thorough understanding of the invention. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of one embodiment of the traction device of the present invention mounted between dual wheels; 
     FIG. 2 is a perspective view of the traction device only; 
     FIG. 3 is a sectional view as viewed on view lines  3 — 3  of FIG. 1; 
     FIG. 4 is a side view of the traction device of FIG. 2 showing both retracted and expanded (in phantom) conditions thereof; 
     FIG. 5 is another embodiment of the traction device; 
     FIG. 6 is an embodiment of the traction device as applied to a single wheel; 
     FIG. 7 illustrates the traction device including an air source for automatic actuation of the device; 
     FIGS. 8 and 9 are views of a traction device as applied to a single wheel in accordance with the alternative embodiment of the invention; 
     FIGS. 10 and 11 are views illustrating a further alternative embodiment the invention; 
     FIGS. 12 and 13 are views of a further embodiment wherein a traction device is applied to a single wheel; 
     FIGS. 14 and 15 are views of a still further embodiment of a traction device as applied to a single wheel; 
     FIGS. 16 and 17 are views of another embodiment of a traction device applied to a single wheel; 
     FIGS. 18-24 illustrate a wheel having a replaceable tread portion; and 
     FIGS. 25 and 26 illustrate another embodiment of a traction device applied to a single wheel. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Refer now to FIG. 1 of the drawings that illustrates a traction device  10  mounted between a set of dual wheels  12 ,  14 . The wheels  12 ,  14  are alike and are given separate numbers to distinguish their mounting position. The dual wheels  12 ,  14  are mounted on a common wheel housing  16  and as shown the outer wheel  12  is spaced from the inner wheel  14 . This is typical of the dual wheel mounting arrangement in which a space is provided between the outer wheel  12  and the inner wheel  14 . Note from FIG. 3 that the rim  13  of both of the inner dual wheel  14  and outer dual wheels  12  are mounted to the wheel housing  16  on conventional mounting lugs  15  (or bolts) that retain the inner wheel  14  and outer wheel  12  securely onto the wheel housing  16 . The configuration of the rims  13  of the outer wheel  12  and the inner wheel  14  positions the wheels  12 ,  14  at a distance from each other as will be noted from FIGS. 1 and 3. 
     The traction device  10  not assembled to the dual tires is illustrated in FIGS. 2 and 4. The traction device  10  has a rim  22  on which a tire  24  of the traction device  10  is mounted. The rim  22  has holes  26  that are alignable with the mounting lugs or bolts  15  of the wheel housing  16 . A valve stem  28  (FIG. 2) is provided to inflate the tire  24  by pressurized air and to deflate the tire  24  by exhausting the pressurized air. The tire  24  of the traction device  10  has studs  20  extending from its peripheral surface  32 . The tire  24  has expansion slots  30  that are arranged to permit the radial expansion and contraction of the tire  24 . As shown, the slots  30  extend across the peripheral surface  32  of the tire  24  and extend into the side walls  34 ,  36 . The tire  24  is arranged to expand radially as pressurized air is introduced via the valve stem  28 . 
     The introduction of pressurized air through the valve stem  28  to the interior of the tire  24  will force the tire  24  to expand radially outward and thus increase its diameter. The slots  30  are configured to enhance the uniform radial expansion of the tire  24  and to minimize the axial or lateral expansion of the tire  24 . 
     The mounting arrangement of the traction device  10  is further illustrated in the sectional view of FIG.  3 . In this embodiment, the wheels  12 ,  14  are of the same construction and have been assigned numbers  12 ,  14  to distinguish the inner wheel from the outer wheel. Wheels  12 ,  14  have a rim  13  that has a hole pattern that mates with the conventional mounting lugs of the wheel assembly  16 . 
     As shown in FIG. 3, the rim  22  of the traction device  10  is sandwiched between the rims  13  of the inner wheel  14  and outer wheel  12 . The rim  13  of the wheels  12 ,  14  and the rim  22  of the traction device  10  are mounted to the wheel assembly  16  and are secured by the mounting lugs or bolts  15 . The traction device  10  is thus rotatable with the wheels  12 ,  14 . The valve stem  28  extends through a conventional opening provided in the rim  13  of the wheels  12 . This provides access to the valve stem  28  for inflating and deflating the tire  24  of the traction device  10 . As shown in the figure, the tire  24  of the traction device  10  is illustrated in the deflated state (contracted) in solid lines and the tire  24  is shown in the inflated (expanded) state in dashed lines. In the contracted state, the tire  24  has been deflated to contract radially inward and thus the diameter of the tire  24  is less than the diameter of the wheels  12 ,  14 . In the expanded state the tire  24  has been inflated with pressurized air to expand the tire radially to exceed the diameter of the wheels  12 ,  14 . 
     The illustration of the tire  24  in the expanded state is exaggerated for illustrative purposes. The tire  24  is expanded such that the studs  20  will extend beyond the diameter of the wheels  12 ,  14  to engage the supporting surface (roadway). The wheels  12 ,  14  still supports the vehicle weight and the tire  24  provides the traction. 
     Referring to the dashed outline of the tire  24  of the traction device  10  of FIGS. 3 and 4 (which shows the traction device  10  in the expanded state) the tire  24  has been inflated by pressurized air. The tire  24  has expanded radially such that the diameter of the tire  24  is greater than the wheels  12 ,  14 . The studs  20 , when the tire  24  is in the expanded state, will extend beyond the diameter of the wheels  12 ,  14  to engage the roadway R projected through an ice or snow covering S. The studs  20  in engagement with the roadway R will provide the necessary traction required when the vehicle encounters slippery surfaces caused by ice, snow and the like. (The representation of ice/snow covering S and the projection of the studs to the roadway R is illustrative only of the expandability function of the invention and is not intended to accurately depict the manner by which gripping occurs, e.g., the studs in packed snow or ice conditions will not necessarily penetrate through to the bare roadway.) 
     FIG. 5 illustrates another known mounting arrangement for dual wheels on a vehicle. The wheels  42 ,  44  are of the same type and are reversible. That is, wheel  42  can be mounted in the position of wheel  44  and vice versa. Wheels  42 ,  44  have a rim  46  that is mountable onto a wheel housing spider  48 . The conventional mounting of the wheels  42 ,  44  includes a spacer  50  positioned on the spider  48  between the wheels  42 ,  44 . The spacer  50  is provided to space the wheels  42 ,  44  from each other on the wheel spider  48 . In this embodiment, the spacer  50  is altered to support the traction device  10 . The spacer  50  includes a wheel supporting rim  52  on which the tire  24  of the traction device  10  is mounted. The valve stem  28  is extended through a hole  54  provided in the spacer  50  with the valve stem  28  extending between two adjacent spiders  48 . The tire  24  of the traction device is inflated to increase the diameter of the tire  24  to that which is larger than the wheels  42 ,  44  and thus to engage the road surface to provide the necessary traction. Similarly, the tire  24  is deflated to contract the tire  24  radially inward such that its diameter is less than the wheels  42 ,  44 . 
     FIG. 6 illustrates the traction device  10  arranged for use with a single wheel  70 . As shown, the traction device  10  and the wheel  70  are mounted to a wheel assembly  78  on conventional mounting lugs. The wheel  70  has a rim  72  configured to fit against the rim  22  of the traction device  10 . The rim  72  has an opening  74  through which the valve stem  28  protrudes. The tire  24  of the traction device  10  is illustrated in the contracted state in solid line and in the expanded state in dashed lines. It is contemplated that the tire  24  may be constructed to have radial as opposed to axial expansion and alternatively a side plate  27  (in phantom lines) may be secured to the tire rim or otherwise to take the place of the moving dual wheel and force radial expansion. 
     The tire  24  of the traction device is inflated by conventional air sources, such as a compressed air tank. The tire  24  of each traction device  24  mounted on a vehicle may be individually inflated by manually applying pressurized air to each tire  24 . Most large dual wheel vehicles have their own on board air source to provide air to the vehicle brakes, air horn and the like. Each tire  24  may thus be coupled to the air source by suitable controls and air lines to remotely inflate and deflate the tires  24  of the traction devices  10 . Referring to FIG. 7, an air line  80  is coupled to the valve stem  28  of the tire  24  of the traction device  10 . The air line  80  extends through the wheel housing  16  and is coupled to an air line  82  that extends to control valve(s)  84 . The control valve  84  is connected to an air supply tank  88  of the vehicle by an air line  86 . Additional air lines  82  are provided to couple the control valve  84  to each of the wheel housings  16  (and thus each tire  24 ). The control valve  84  preferably is arranged to supply air to inflate each tire  24  or deflate each tire either individually or simultaneously. The operator of the vehicle may thus inflate or deflate the tires  24  remotely without the need of stopping the vehicle. 
     Referring now to the embodiments of FIGS. 8-24, FIGS. 8 and 9 of the drawings illustrate a traction device applied to a single wheel  100 . Studs  20  are provided at spaced intervals along the center of the tread portion  102 . The center tread portion  102  in combination with the tire wall  104  forms an expandable chamber  106  as shown in FIG. 9. A hose  108  connects the chamber  106  to a valve stem  110  (valve mechanism) to permit applying air pressure to the chamber  106  or relieving air pressure from the chamber  106 . Air pressure is applied by a known air source, either remote or self contained on the vehicle. The chamber  106  is shown in the expanded state in FIG. 9 which forces the center tread portion  102  outwardly with reference to the wheel  100  to thus place the studs  20  into engagement with the ground surface. FIG. 8 shows the chamber  106  collapsed. That is, the air has been released from the chamber  106  and the natural resilience of the center tread portion  102  retracts the studs  20  inwardly toward the tire wall  104 . 
     FIGS. 10 and 11 illustrate another traction device applied to a wheel  120 . A center tread portion  122  is provided between the side treads  124  and  126 . Studs  20  are provided at spaced intervals along the center tread portion  122 . The center tread portion  122  is expandable as shown in FIG.  11  and is contractible as shown in FIG.  10 . The center tread portion  122  is expanded by the application of air pressure to a chamber  127  formed within the center tread portion  122  and is contractible by releasing the air from the chamber  127 . A hose  128  couples the chamber  127  to a valve stem  130 . The center tread portion  122  in the expanded state as is shown in FIG. 11 places the studs  20  in contact with the road surface to provided added traction. 
     FIGS. 12 and 13 illustrate a traction device similar to those of FIGS. 8 and 9 except that in FIGS. 12 and 13 studs  20  are provided near each side edge  133  of the tire tread  132  on the wheel  121 . An expandable chamber  134  is provided for each row of studs  20 . A hose  136  couples each of the chambers  134  to a valve stem  138 . The chambers  134  are expandable as shown in FIG.  13  and are contractible as shown in FIG.  12 . The chambers  134  are expanded by applying air pressure to the chambers  134  and the chambers  134  are contracted by releasing the air from the chambers  134 . When the chambers  134  are expanded, the studs  20  are moved radially outward to contact the road surface. 
     FIGS. 14 and 15 are similar to the traction devices of FIGS. 12 and 13 except that the chambers  134  are joined by a duct  142  provided in the tread  132  of the wheel  140 . Preferably multiple ducts  142  are provided at spaced intervals along the length of the chambers  134 . As shown in FIGS. 14 and 15, a single hose  146  is coupled to one of the chambers  134  and is connected to a valve stem  148 . The chambers  134  are shown in the expanded state in FIG.  15  and are expanded by the application of air pressure. FIG. 14 illustrates the chambers  134  in the contracted or collapsed state and the chamber  134  is collapsed by releasing the air applied to the chamber  134 . 
     FIGS. 16 and 17 illustrate another traction device applied to a wheel  150 . In this embodiment, studs  20  are provided at spaced intervals in two rows around the periphery of the wheel  150 . The studs  20  project from a tread portion  152  of the wheel  150 . The wheel  150  has side tread sections  154  and  156  and a center tread section  158 . Each of the tread sections  154 ,  156  and  158  have a chamber  160  that is expandable and contractible. A hose  162  connects the chambers  160  to a valve stem  164 . The chambers  160  are collapsible as illustrated in FIG. 16 to place the studs  20  in contact with the road surface. The chambers  160  are expandable as shown in FIG. 17 with the tread sections  154 ,  156  and  158  being expanded beyond the height of the studs  20  to thus keep the studs  20  out of contact with the road surface. 
     FIGS. 18 and 19 illustrate a traction device as applied to a single wheel  170 . In this embodiment, the wheel  170  has a tread  172 . The tread  172  has channels  174  formed (see FIGS. 23 and 24) around its periphery with the channels  174  being of a depth to receive replaceable tubular section  176 . The tubular section  176  is provided with studs  20 . The tubular section  176  is removably mounted in the channels  174  provided in the tire tread  172 . The profile of the channels  174  in the tread  172  will have a profile that matches the profile of the tubular section  176  (see FIG.  23 ). The tubular section has sufficient elasticity such that they may be installed and removed on the wheel  170  as required. The tubular section  176  with studs  20  would be installed on the wheel  170  when additional traction is required such as in ice or snowy conditions and the studs  20  will provide the added traction required. Each tubular portion  176  is inflatable (expandable) by pressurized air and as shown in FIGS. 18,  19 , the tubular portion  176  has a stem  180  that extends through an aperture  171  into the cavity portion of the wheel  170 . A coupler  182  connects the stems  180  to an air line  184 . Air line  184  is connected to a conventional valve stem  186  for inflating and deflating the tubular portion  176 . The tubular portion  176  is contractible by releasing the pressurized air. 
     The tubular portion  176  is inflated by pressurized air so that the tubular portion  176  will be substantially even with the tread  172  of the wheel  170 . When the tubular portion  176  is inflated to be even with the tread  172 , the studs  20  will project beyond the tread  172  and the studs  20  of the tubular portion  176  thus will be in contact with the ground surface to provide additional traction. 
     Tubular portion  178 , as illustrated in FIGS. 20 and 21, is a filler unit that is most often utilized when additional traction afforded by the studs  20  is not required such as during the summer months. The tubular portion  178  when inflated (FIG. 21) will have its upper surface substantially even with the tread  172  of the wheel  170 . The tubular portion  178  has a profile that will mate with the profile of the channel  174  (FIG.  24 ). The tubular portion  178  has a stem  180  that extends through the aperture  171  into the cavity portion of the wheel  170 . A coupler  182  connects the stem  184  to an air line  184 . Air line  184  is connected to a conventional valve stem  186  for inflating and deflating the tubular portion  178 . 
     FIG. 22 illustrates a tubular portion  178 ′ that is removably mounted in the channel  174  of the wheel  170 . The tubular portion  178 ′ has a stem  181  that fits in the aperture  171  to provide a seal for the cavity of the wheel  170 . The tubular portion  178 ′ has sufficient elasticity to permit mounting the tubular portion  178 ′ in the channel  174  formed in the tread  172 . It will be appreciated that the tubular portions  178 ′ may also be provided with studs  20 . 
     FIGS. 25 and 26 illustrate another embodiment of a tire  300  that has extendable and retractable studs  302 . The tire  300  has an expandable and retractable chamber  304 . A conduit  306  is connected to a known air source and valve system to supply air to and exhaust air from the chamber  304 . 
     When the chamber  304  is expanded by applying air pressure, the stud  302  is moved outward and downward as shown in FIG. 25 so that the stud  302  will engage the road surface. When air is released from the chamber  304 , the chamber retracts as illustrated in FIG. 26 which retracts the stud  302  so that it will not come into contact with the road surface. 
     Those skilled in the art will recognize that modifications and variations may be made without departing from the true spirit and scope of the invention. The invention is therefore not to be limited to the embodiments described and illustrated by is to be determined from the appended claims.