Abstract:
An all-weather tire includes features that enhance safety and usability in a variety of driving conditions as well as some manufacturing processes that may be used during the production and provides an all-weather tire having selectively deployable and retractable studs for greater traction when needed. The tire includes a toroidal shell enclosing an air-filled chamber and a plurality of stud actuation chambers contained within the shell for selectively deploying studs to extend past the tire&#39;s outer radial surface for engaging a roadway or surface. The studs may be retracted when no longer needed. A mechanical pump assembly or plurality of such assemblies powered by compression of the tire engaging the roadway may be used as a power source for generating pneumatic pressure and an internal valve assembly or assemblies may be used to route the pneumatic pressure appropriately. The pump and valve assemblies may be controlled either mechanically or electrically.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/628,386 filed Oct. 31, 2011 and U.S. patent application Ser. No. 13/663,918 filed Oct. 30, 2012 entitled All Season Safety Tire. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     Typically, automobile operators who live in snow zones must cope with the possibility that at times roads may be snow or ice covered. This frequently necessitates changing the tires to snow or studded tires to provide greater traction during such events. Additionally, the snow or ice condition may be short-lived or be a function of altitude requiring removal of enhanced traction tires when the condition is no longer present. Changing tires is time consuming and frequently must be done while pulled over on the side of the road in poor weather conditions or done by a garage which can be time consuming and costly. While studded tires may be permanently used in some states during a designated snow season, these tires tear up roadways thus leading to high maintenance costs. 
     BRIEF SUMMARY OF THE INVENTION 
     An all-weather tire includes features that enhance safety and usability in a variety of driving conditions as well as some manufacturing processes that may be used during the production and provides an all-weather tire having selectively deployable and retractable studs for greater traction when needed. 
     An all-weather tire includes a toroidal shell enclosing an air-filled chamber and a plurality of stud actuation chambers contained within the shell for selectively deploying studs to extend past the tire&#39;s outer radial surface for engaging a roadway or surface. The studs may be retracted when no longer needed. A mechanical pump assembly or plurality of such assemblies powered by compression of the tire engaging the roadway may be used as a power source for generating pneumatic pressure and an internal valve assembly or assemblies may be used to route the pneumatic pressure appropriately. The pump and valve assemblies may be controlled either mechanically or electrically. 
     This provides a self-actuating stud deployment feature for the tire that obviates the need to change from smooth surface tires to studded tires in order to have all-weather traction in snow or ice. 
     The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view of a tire employing an extendable and retractable stud system. 
         FIG. 2  is a perspective view of the tire of  FIG. 1  with the outer tread layer removed. 
         FIG. 3  is a cutaway view taken along line  3 - 3  of  FIG. 1 . 
         FIG. 4  is a perspective view of a stud actuation chamber with the studs in a retracted position. 
         FIG. 5  is a perspective view of the stud actuation chamber of  FIG. 4  showing the studs in a deployed position. 
         FIG. 6  is a block schematic diagram of a pneumatic circuit for a group of stud actuation chambers. 
         FIG. 7  is a block schematic diagram of a system in an automobile for selectively deploying retractable tire studs. 
         FIG. 8  is a detailed schematic diagram of a hydraulic circuit showing the operation of the valve mechanism of  FIG. 6 . 
         FIG. 9  is an alternative simplified hydraulic circuit that may be employed in lieu of the circuit of  FIG. 8 . 
         FIG. 10  is a partial cutaway view of the tire of  FIG. 3  showing the tire with a full tread. 
         FIG. 11  is a partial cutaway view of the tire of  FIG. 3  showing the tire with a reduced or worn tread. 
         FIG. 12  is a partial perspective view of the tire of  FIG. 1  with the outer tread layer partially removed to expose the radial belts underneath 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An all-weather tire includes a conventional belted radial tire having a deployable stud feature. The studs are components of stud lift actuators, which are embedded in the outer shell of the tire. In a preferred embodiment, the studs are selectively deployed and retracted by a pneumatic system that may be operated from within the inside of a vehicle. An electrical system may be used to selectively power pneumatic valves that open and close, directing air or other pneumatic fluid into the stud lift actuators for deployment or retraction. 
     The studs are housed in stud actuator assemblies, which are lift chambers connected by valves to a source of air under pressure. In one embodiment, this source may be the hollow interior of the tire itself. It takes little pressure to deploy the studs, so any drop in interior tire pressure is negligible. The actuator assemblies are preferably arranged in groups of 8 or 10 or 12, each group having a dedicated pneumatic valve assembly. 
     In addition, the preferred system may be configured to re-inflate the tire when the studs are retracted. This is a self-actuating feature made possible by a pump that is powered by the action of the tire rolling over a road or other surface as the vehicle is driven. 
     The pump may be configured as an elongate radial tube having a bladder. This bladder may be embedded in the outer shell of the tire, extending circumferentially around the periphery of the tire and extending slightly radially outwardly of the tire&#39;s tread when inflated. The bladder has an inlet coupled to ambient air through a selectively operable valve and an outlet coupled to the hollow interior of the tire. When the tire rolls along a roadway or other surface, it compresses the bladder at a pinch point forcing air into the tire&#39;s interior through a one-way check valve. Thus, the roadway acts as a pinch roller, depressing the bladder, thereby forcing air out of the forward end outlet ahead of the pinch point. At the same time, the flattened bladder to the rear of the pinch point has natural resiliency, and as it springs back into shape, a vacuum is created which sucks outside air into the bladder through a one-way inlet check valve. The pump may consist of multiple pump assemblies spaced about the outside radial surface of the tire. There may be a plurality such as three or five such assemblies or there could be only one. 
     The stud lift actuator mechanisms comprise chambers, which include a cylindrically-shaped bracket made at least in part, of a resilient material, a bladder and a lift table recessed into the outer surface of the tire. The stud lift actuators are coupled to a source of fluid under compression through conduits embedded in the tire or routed along the inside interior surface of the tire&#39;s outer shell. The fluid could be the air pressure in the interior of the tire itself. The conduits are connected to a valve assembly, which selectively serves to inflate or deflate bladders that deploy or retract the studs. 
     In a preferred embodiment, each bracket in an actuator assembly has four studs which are pins rotatably mounted on the bracket to rotate from a flat retracted position to an upright position. In the center of the bracket, there is a bladder with a disk attached at the top that functions as a lift table. In a retracted state, the pins are folded to lie across the disk. A valve assembly selectively couples the interior of the tire to the bladders when deployment is desired. As the bladder inflates, it forces the lift table up, thereby forcing the pins to rotate in the brackets until they are upright. The table rises until it is flush with the tire&#39;s outer surface. At this point when the lift table has reached its stroke limit, the pins extend past the outer radial surface of the tire in their fully deployed state, thus engaging the road surface that may be snow or ice-covered. The pins thus provide traction for the tire. 
     Since the stud lift chambers are embedded in the tire but are recessed into the surface, the studs also serve to indicate wear conditions. As the tire tread wears away, the studs eventually begin to contact the road surface making a clicking noise that alerts the operator that the tire tread is thin and that the tire needs replacing. 
     Referring now to the drawings, a tire  10  includes a toroidal shell  12  enclosing a hollow interior air space  14  (refer to  FIG. 3 ). The tire  10  is mounted on a wheel  16 , the rim of which seals the air space  14 . The tire shell  12  can be a radial tire constructed of a plurality of radial belts  13  (see  FIG. 11 ) covered by an outer layer of rubber  18  which may include a tread designed to grip the road surface and prevent sliding. Embedded in the outer shell are pluralities of pump assemblies  20   a ,  20   b  valve assemblies  22   a ,  22   b  and stud actuation chambers  24   a ,  24   b , and  24   c  all connected by pneumatic lines such as lines  26   a ,  26   c . Not all pneumatic lines, pump assemblies, and stud actuation chambers are shown, it being understood that these are distributed about the radial surface of the tire. These components may be encased on the outer rubber layer  18  or they may be placed between radial plies or layers  13 . Still another option is to affix the valve assemblies to the interior surface of the shell with the pneumatic lines coupled to the stud actuators through the outer shell. 
     With particular reference to  FIGS. 2 and 3 , a typical pump assembly  20   a  is embedded in the tread. There may be a plurality of such pump assemblies distributed about the outer periphery of the tire. As shown best in  FIG. 2 , each pump assembly like pump assembly  20   a  has its own valve assembly  22   a  and is coupled to a plurality of stud actuation chambers like chambers  24   a  via pneumatic lines  26   a.    
     The pump assembly  20   a  comprises an elongate tube  30   a  that extends circumferentially along the outer surface of the tire. The tube  30   a  is inflated so that in its active state it bulges outwardly radially a short height above the tread surface  18  of the tire. The tube  30   a  is essentially a bladder that inflates. The bladder may be the tube itself or it may be an internal bladder  31  (shown in dashed outline) encased in a shell forming the tube  30   a  for added protection. The tube  30   a  is coupled to the valve assembly  22   a  by conduits  32  embedded in the outer shell. A second set of conduits  34  couple the valve assembly  22   a  to the interior air space  14  of the tire  10  and a conduit  36  vents to ambient atmosphere. The valve assembly  22   a  is coupled to a plurality of stud actuation chambers  24   a  by a pneumatic line  26   a  as shown best in  FIG. 3 . Another pump assembly such as pump assembly  20   b  has a valve assembly  22   b  and is coupled to stud actuation chambers  24   b . Similarly a third group comprises stud actuation chambers  24   c  coupled to their own dedicated pump and valve assembly (not shown in  FIG. 3 ). There can thus be groups of pump, valve assemblies, and stud actuation chambers distributed about the circumference of the tire. The exact number may depend upon various factors such as the size of the tire and the size of the pump assembly, e.g., the chosen length of the tube such as tube  30   a . However, preferably there are an odd number of groups such as three or five. This keeps the tire balanced. 
     The hydraulic circuit of a typical pump, valve and stud actuator group is shown in  FIG. 6 . In this figure, a pump assembly  40  is coupled to a valve assembly  42  via two lines, an inlet line  44  and an outlet line  46 . Inlet line  44  has a one-way check valve  44   a  and outlet line  46  has a one-way check valve  46   a . The valve assembly  42  is connected to a stud actuation chamber  48  via line  50 . It is to be understood that stud actuation chamber  48  schematically represents an entire plurality of such chambers as shown in  FIGS. 1 and 2 . Lines  52  and  54  couple from the valve assembly  42  to the interior air space  14  and to ambient atmosphere, respectively. Line  54  has two connections to different parts of the valve assembly  42  as will be explained below. 
     The valve assembly  42  is shown in detail in  FIG. 8 . A first two-way, three-position valve  50  connects the interior air space  14  either to the pump chamber outlet line  46  or to the stud actuation chambers  48  via line  51 . A second two-way, three-position valve  52  connects the stud actuation chambers  48  to ambient atmosphere (outside tire) via line  53  or to the inlet line  44  through a pair of one-way check valves  44   a ,  47 . A one-way 2-position valve  56  couples the inlet line  44  to the pump chamber  40  to ambient atmosphere by lines  54  and  57 . 
     An alternative arrangement is shown in  FIG. 9 . In this configuration, the interior air space of the tire  14  is coupled through a two-position valve  60  via pneumatic lines  62  and  63  to a plurality stud actuation chambers  64 . The stud actuation chambers  64  may be vented to ambient atmosphere through the valve  60  via line  66 . The tire pressure itself is utilized to force deployment of studs when the valve  60  opens. When the studs are retracted, it may be necessary to re-inflate the tire to recommended pressure. 
     Referring now to  FIGS. 4 and 5 , a typical stud actuation chamber  70  comprises a circular base  72  having four brackets  74   a - 74   d . The base is placed on top of the belts  13  in cylindrical voids in the outer rubber layer  18 . The brackets  74   a - 74   d  may be constructed of a resilient material. Contained within the brackets  74   a - 74   d  are studs  76   a - 76   d , which may be metallic in composition. These studs will engage a road or other surface when they are deployed as will be described below. The studs  76   a - 76   d  are rotatably mounted in the brackets on flat pins such as pin  77  which extend through apertures in the brackets. Because the brackets are made of resilient material such as a stiff rubber, the flat pins can be made to rotate in the apertures which will deform to accommodate the shape of the pins such as pin  77  and then apply a restoring force when the bladder  82  deflates and the pins  76   a - 76   d  are allowed to pivot in the brackets and thereby retract. 
     The studs  76   a - 76   d  are forced to deploy by the action of a lift table  80 , which may be forced to rise by the inflation of a bladder  82 . The lift table  80  rests on top of the bladder  82  and may be attached to it by a grommet  81  or adhesive or any other attachment mechanism. The bladder  82  is pneumatically actuated through a pneumatic line such as line  50  in  FIG. 6 . When the line is pressurized, the bladder  82  inflates causing the lift table  80  to rise. As the lift table  80  rises it forces the studs  76   a - 76   d  to rotate in the brackets  74   a - 74   d  so that they stick straight up and thereby extend radially outwardly of the tire surface  18 . When the bladder  82  deflates, the studs resume their initial state under the restoring force of the resilient brackets  74   a - 74   d  applying torsion on the flat pins such as pin  77 . 
     The system may be operated in a number of ways and one such configuration is shown in  FIG. 7 . A manual switch  100 , a TPMS (tire pressure monitoring system)  104  and an auto sensor  102  are all coupled to a receiver  106 . The receiver  106  is an electronic device that receives signals from the sensors or switches and provides output signals to actuate a valve assembly  108 . The valve assembly  108  may be one that is operated by solenoids or other electronic means (not shown) such as various types of electronic actuators. Power can come from the auto&#39;s internal battery or from a generator contained within the wheel assembly. A manual valve assembly  110  may also be provided in addition to the valve assembly  108  for certain selected functions. This valve could be located on the tire itself and could be used as an alternative means of controlling deployment/retraction of the studs for each tire. In such a case, the valve assembly  108  would not be needed since valve assembly  110  could be used to connect the interior of the tire to the stud actuation chambers, as in the embodiment of  FIG. 9 . Alternatively, it could be hard-wired within the car. The valve arrangement of  FIG. 9  would be especially well suited for this configuration. As shown in  FIGS. 6 ,  8  and  9  the valve assembly  108 , which schematically may represent a plurality of such valve assemblies, selectively inflates and vents to the pump chambers  112  and the stud chambers  114 . Many automobiles have auto sensors such as sensor  102 . These devices automatically monitor conditions such as temperature and humidity to indicate the presence of ice. In some instances, the condition is annunciated to the driver audibly but the annunciation signal could also be used to provide a stud deployment command to the receiver  106  and thence to the valve assembly  108 . The receiver  106  is an electronic module that receives commands or sensor data and produces an output signal of sufficient voltage to run pumps or actuators as necessary. 
     In operation, a stud deployment command causes the internal pressure of the tire itself to inflate the bladders  82  in the stud actuation chambers  48  (refer to  FIGS. 6 and 8 ). Only a few psi are required to deploy the studs and the tire can be re-inflated by use of the pump assemblies after the studs are retracted. When the studs are to be deployed, the valve  50  is left shifted to connect the interior air space  14  to each group of stud actuation chambers  48 . Valve  52  remains closed. When the studs are to be retracted, valve  52  is right shifted venting the stud actuation chambers to ambient and valve  50  is right shifted allowing the pump chamber  40  to re-inflate the interior airspace  14 . At the same time, valve  56  is right shifted to allow the pump chamber to re-inflate from outside ambient. This will happen because as the tire rotates it squeezes air out of the tube  30  forward of the road/tire contact area or “pinch point”. Behind the pinch point a vacuum is created which will draw air back in. Additionally or as an alternative, the valve  52  may be left shifted so that air is drawn out of the stud actuation chamber bladders by the vacuum behind the pinch point. This collapses the bladders and allows the studs to retract. 
     Other means may be employed to power the stud actuation chambers and these may include pumps carried in the interior of the tire which could be battery powered and activated by a wireless signal. The preferred system uses the air pressure within the tire itself which can then be replenished when the studs are retracted. This obviates the need to re-inflate the tire via a mechanical garage pump. A very simple way of accomplishing this function is shown in  FIG. 9 . The manual valve  60  is shown in the deployment mode, connecting the interior air space  14  with stud actuation chambers  64  thereby inflating their bladders and causing the lift tables to rise as described above. A right shift decouples the stud actuation chambers from the interior air space and allows the stud actuation chambers to vent to outside ambient. 
     Another feature of an all-weather tire is shown in  FIGS. 10 and 11 .  FIG. 10  shows a tire with most of its tread on the outer rubber layer  18  remaining. The stud actuation chamber  48  is recessed into the layer  18  and so the studs do not contact the road. However as the tread wears down it reaches a point as shown in  FIG. 11  in which the studs  76   c  and  76   a , which are slightly curved, stick out past the outer layer  18 . When this happens, the driver will hear a clicking sound indicating that the tread is worn and a new tire is needed. This is an audible safety feature that is inherent in the all-weather tire design of  FIGS. 1-9 . In addition, the studs will not damage the roadway because they are resiliently mounted and will compress into the tread. 
     While an all-weather tire has been described that makes use of a specific pump and valve arrangement for deploying and retracting studs, other methods, and apparatus may be employed. While a plurality of pump assemblies, valve assemblies, and stud actuation chambers may be preferred, it is possible that only one such pump assembly and valve assembly may be used to power all the stud actuation chambers. In another example, instead of using the interior pressure of the tire to deploy the studs, a dedicated pump assembly may be used. The pump assembly may be electrically powered and could be contained within the tire or positioned on a wheel rim. Actuation by wireless such as BLUETOOTH could be used to turn on the pump and both inflate and deflate the stud actuation chambers. Additionally, the stud actuation chambers could take different forms besides the cylindrical wells having a bladder and lift table as shown in the drawings. Such studs could comprise telescoping rods coupled to a pneumatic line or lines and could be deployed by linear actuators that respond to pneumatic pressure. Another possibility is that the studs, instead of rotating to deploy, could be carried on the lift table as straight linearly acting rods or pins held in guides. Another alternative is that the pump assembly could be used to actuate the studs directly instead of tapping into the interior pressure of the tire to do so or the pump assembly could inflate a pressurized canister that would store pressure for later deployment. 
     The terms and expressions that have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.