Self-tightening snow chain and methods of use

Self-tightening snow chain for attachment to a vehicle wheel to provide traction. The preferred self-tightening snow chain includes a traction cable and a tensioning device including a housing having a top including a set of housing teeth, a bottom and at least one aperture; a lever interconnected to the housing; a ratchet spool within the housing having a set of ratchet teeth that mate with the housing teeth and a channel between upper and under surfaces to receive a cord that is interconnected with the ratchet spool; a tension spring that places a bias on the ratchet spool toward a wind-up direction; and a wave spring. A preferred tensioning device includes a cord sub-unit having two knobs, one on each end, and a grommet encircling the cord. A method of assembling the tensioning device is also disclosed.

FIELD OF THE INVENTION

The present invention relates generally to snow chains, particularly, snow chains that self-tighten to ensure proper fit. More particularly, the present invention relates to self-tightening snow chains having a tensioning device including a winding device and a tensioning cord, the snow chains having a tensioned mode when secured for use on a wheel of a land vehicle and a separate extended mode, wherein the tensioning cord, interconnected with the winding device is released to extend away from the winding device to permit the snow chain to be easily engaged with the wheel of the land vehicle prior to securing the snow chain to the wheel. In alternate embodiments, the present invention relates to self-tightening snow chains that self-tighten when a plurality of cords are tensioned by a single winding device. In further embodiments, the present invention relates to a tensioning device for a snow chain that places a spring bias upon a tensioning cord or a plurality of tensioning cords and/or is resistant to infiltration of dirt, debris and moisture. Methods of providing and using these inventions are also disclosed.

BACKGROUND OF THE DISCLOSURE

Self-tightening snow chains have been used to provide vehicles with improved traction when driving on irregular surfaces where poorer traction is anticipated (i.e. ice or snow covered surfaces, off-road or backcountry terrains). Numerous states require the use of snow chain under certain weather conditions to mitigate potential hazards. Most models of snow chains require retightening after initial chain installation, where all of the wheel chains need to be retightened after the vehicle has been slowly driven forward or backward. It is essential that snow chains fit properly to obtain proper performance and increase durability. Having to retighten the cables is burdensome for the user and has costly consequences if forgotten or neglected.

Because proper fit of the snow chains is so essential, self-tightening snow chains have been developed. One of these devices is disclosed in U.S. Pat. No. 6,213,421 to Franklin. The Franklin patent discloses a clamping lock for a traction device. The lock has a single clamping rope connected to a winding device within a housing. The winding device is pre-tensioned in the wind-up direction. Toothing is provided laterally around the winding device. There is an actuating lever attached to the housing that has three positions: a first catch position, which allows the clamping rope to move in or out of the housing; a second wind-up position, which unlocks the rope so it may move into the housing, thereby tightening the clamping rope; and a third locked position wherein the clamping rope is locked in its current position. The lever controls a pawl. Whether or not the clamping rope may be pulled in or out of the housing depends on whether the pawl is engaged with the teeth on the winding device.

Self-tightening snow chains having tensioning devices of this kind are difficult to secure to a wheel of a vehicle with two hands. A user may need to let go of the cord in order to better grip the tensioning device or grab the corresponding hook on the snow chain. In order to prevent the cord from being pulled back into the housing, the user must lock the cord in both directions to keep the cord in the extended position. Then, the cord would need to be unlocked to extend further, again requiring releasing either the cord or the corresponding hook. Additionally, self-tightening snow chain tensioning devices that can only tighten one cord are less cost effective because numerous self-tightening tensioning devices are required on each snow chain to tighten each cord.

Of further concern, self-tightening snow chain tensioning devices of this kind are made by simply screwing two flat-edged housing pieces together. Dirt, debris and moisture may easily penetrate this type of joint and cause damage to the mechanisms inside the housing. Additionally, the use of actuating levers creates an easy path for dirt, debris and moisture to enter and damage the device. It is also noted that the tensioning cord is generally equipped with crimped on or cast on ends and that one of these ends is then passed through a grommet and that the grommet and the cord are then incorporated into the tensioning device during assembly. In order to accept the crimped or cast on end, the opening in the grommet is required to be quite a bit larger than the diameter of the cord and the difference in size provides another area where an easy path is provided for dirt, debris and moisture to enter and damage the device.

SUMMARY OF THE INVENTION

The present invention provides a self-tensioning snow chain for attachment to a wheel of a vehicle, the self-tensioning snow chain includes a snow chain; and a tensioning device. The tensioning device includes (1) a housing having a top including a set of housing teeth, a bottom and at least one aperture defined by the top and the bottom when joined together; (2) a lever interconnected to the housing; (3) a cord; (4) a ratchet spool having a set of ratchet teeth on an upper surface, the ratchet teeth constructed and arranged to mate with the housing teeth, an under surface and a channel between the upper surface and the under surface in which sufficient space is provided to receive the cord, wherein the cord is interconnected with the ratchet spool; (5) a tension spring interconnected with the ratchet spool and constructed and arranged to place a bias on the ratchet spool toward a wind-up direction; and (6) a wave spring positioned between a top surface of the bottom of the housing and the under surface of the ratchet spool to bias the ratchet spool in the direction of the housing teeth; wherein the snow chain is interconnected with the tensioning device and the cord can be connected with the snow chain so that the tensioning device can secure the snow chain to the wheel. The snow chain can also be a traction cable or the like that is made out of rope, wire, wire rope, chains and the like.

It is an object of the present invention to provide a self-tightening snow chain that more effectively tightens and is easier to install. It is another object of the present invention to provide a self-tightening snow chain that may tighten a plurality of cords with one winding device, preferably a ratchet spool. It is yet another object of the present invention to provide a self-tightening snow chain having a tensioning device that is resistant to an infiltration of dirt, debris and moisture into the housing.

The present invention achieves these and other objectives by providing a self-tightening snow chain having two modes of operation. First, is an extended or extending mode that allows the user to extend the cord from the housing and release their grip on the cord without having the cord wind-up into the housing. The ability to only allow movement in a wind-out direction is created when the ratchet spool is in down position, where the spool, although biased in a wind-up direction, is blocked from turning in a wind-up direction. To get the ratchet spool in the down position, the user raises the actuating lever until it is perpendicular to the housing. This action forces a cam-lever to push the ratchet spool down. When the ratchet spool is in the down position, the ratchet teeth are disengaged from the housing teeth thereby allowing movement of the ratchet spool in either direction. However, movement in the wind-up direction is prevented by catches on the under surface of a ratchet spool that are pushed into a zone of a stop or stopper where they will be blocked by the stopper, thereby stopping the ratchet spool from turning in a wind-up direction more than a full turn, a half turn or preferably a quarter turn. When the user wants to continue extending the cord, the cord simply needs to be pulled further outward.

Second, is a self-tightening mode wherein the cord may only move in the wind-up direction. This mode is for when the cord is engaged and in use and the user wants to maintain constant tension on the snow chain without the possibility of the cord extending out. To operate in this mode, the user lowers the actuating lever until it snaps back into a position adjacent to the housing. When the actuating lever is down, the ratchet spool is up. Therefore, the housing teeth and the ratchet teeth are engaged to only allow movement in the wind-up direction. When the ratchet spool is in the up position, the catches cannot be blocked by the stopper, which would otherwise prevent more than a small movement of the ratchet spool in the wind-up direction.

In an alternate embodiments of the present invention, the ratchet and housing teeth may be overcut or undercut. In preferred embodiments, the respective teeth will be undercut at an angle ranging from about 3 to about 30 degrees, preferably about 5 to about 25 degrees more than the 90 degree angle to a horizontal plane b perpendicular to a vertical axis c of the ratchet spool and the housing. In the most preferred embodiment, the respective teeth will be undercut about 20 degrees more than the 90 degree angle to a horizontal plane b perpendicular to a vertical axis c of the ratchet spool and the housing. Therefore, when the teeth are undercut, and the device is in a wind-up mode and the cord is tugged outwardly, the harder the cord is tugged, the more the ratchet teeth will become engaged and resist the cord being moved in the wind-out direction. This is particularly important during normal conditions, when a significant amount of vibration results from interaction between the tire and the road surface.

In another embodiment of the tensioning device of the present invention, a plurality of cords, all interconnected with the same winding device or ratchet spool, may extend from different apertures or openings of the housing. Although it is possible to have more than three cords extend from a single tensioning device, such a device may be difficult to optimize because of the limited room on the ratchet spool, unequal forces that could be placed on each cord when in use and also the potential need for a tension spring that can generate greater winding force on the spool that may be needed to wind a greater number of cords.

Additionally, a lip and groove configuration may be utilized to aid in sealing the housing from dirt, debris and moisture. For example, a lip may trace along the opening of the housing top and a groove may trace along the opening of the housing bottom. When the two housing components are joined together, the lip and groove will mate to form a more secure seal than if two flat surfaces are pressed together. Alternatively, the lip may trace along the opening of the housing bottom and the groove may trace along the opening of the housing top.

To further protect the internal components, a grommet having an opening only slightly larger than the diameter of the cord may be utilized. If the grommet is secured around the cord prior to securing knobs at both ends of the cord, the grommet opening can be smaller than the diameter of the knobs, thereby reducing the size of the passageway in the grommet where dirt, debris and moisture can breach the housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are illustrated inFIGS. 1-16BFIG. 1is a perspective view of a self-tightening snow chain10of the present invention in use on a wheel16(partially shown). The self-tightening snow chain10comprises of a snow chain14and a tensioning device11. Referring now also toFIGS. 2 and 3, the self-tightening snow chain10has a housing12including a housing top12a, an actuating lever26, a grommet32, and a cord20extending through grommet32and connected to a hook18with a first connection member22. The hook18connects to the chain14of the self-tightening snow chain10, to supply tension to the chain14. In this embodiment, there is a second connection point24and third connection point30where parts of the snow chain14are secured to the housing12. Rivets28are placed through rivet receiving openings or recesses29to secure the housing top12ato the housing bottom12b, although any other fasteners such as threaded screws, bolts and nuts, adhesives, double backed tape and the like could be used. The housing top12ahas a recess34to prevent distortion during injection molding, which may additionally be used as a place for company identifiers and the like, if desired.

FIG. 2is a perspective view of the housing12of the tensioning device11shown inFIG. 1. The housing top12acan be secured to the housing bottom12bby rivets or threaded screws (not shown) that may inserted through the holes29. The housing top12aand the housing bottom12bdefine an aperture38for receiving the grommet32that provides a passageway for the tensioning cord20. Additionally, an actuating lever26including a cam126is pivotally connected to the housing top12a.

InFIG. 3, there is illustrated an exploded view of one embodiment of the tensioning device11of the present invention. A wave spring112sits on the inside of the housing bottom12b. The wave spring112is positioned in a way to apply pressure to the ratchet spool100. The tension spring110also rests inside the ratchet spool100and has a crimp122that mates with a notch120in the ratchet spool100to secure the tension spring110to the ratchet spool100. The ratchet spool100has a center channel124running circumferentially around its exterior and is sufficiently wide and deep enough for a cord20to be wound within the channel124around the ratchet spool100. In this embodiment, the under surface132of the ratchet spool100has four catches104. It is not essential that there be four catches104as two to six catches104will result in similar function. More than six catches104is possible but not recommended. As better shown inFIGS. 8A-8B, the catches104prevent the ratchet spool100from rotating in the wind-up direction when they are blocked by the stopper108. The catches104can only be blocked by the stopper108when the ratchet spool100is in the down position (when the cam126is in the down position/the actuating lever26is in the up position). On the top of the ratchet spool100are ratchet teeth102. As seen inFIGS. 8A and 8B, the ratchet teeth102can engage with the housing teeth118located in the housing top12awhen the actuating lever26is oriented in the down position. When the actuating lever26is in the down position, a cam126, which extends from the actuating lever26, is parallel to the plane of rotation of the ratchet spool100. Therefore, there is no added pressure on the wave spring112, which allows the wave spring112to push the ratchet spool100to its up position, engaging the ratchet spool100with the housing teeth118. When the actuating lever26is in the up position/the cam126is in a down position and pushes the top base114down against the ratchet teeth102, which are subsequently pushed down thereby disengaging the ratchet teeth102from the housing teeth118. The top116has slots117for the cam levers26to rotate. The housing teeth118are molded into the housing top12a.

The stopper108has an up position and a down position. Referring now also toFIGS. 4 and 5, showing the arrangement of the catches104, the compression spring106and stopper108in the up position. The compression spring106is attached to the stopper108and they both are placed in the housing bottom12bsuch that the compression spring106applies force to the housing bottom12b. The compression spring106places a bias on the stopper108such that the stopper108will block a catch104should the ratchet spool100be in the down position and rotating in the wind-up direction so that the ratchet spool will not rotate more than 360 degrees in the wind-up direction when the ratchet spool100is in a down position. One preferred tensioning device10includes a housing12having a stop and a set of housing teeth; a winding mechanism including a spool100having set of ratchet teeth102and at least one catch104, the winding mechanism located within the housing12; and a cord20operatively connected to the spool100; wherein the winding mechanism has two positions that control the movement of the cord20, the first position being a wind-up position where the cord is pulled into the housing and cannot be pulled outwardly from the housing, the second position being a wind-out position wherein the cord may be pulled outwardly from the housing. In this preferred embodiment, if the cord20is pulled outwardly from the housing12and then released, while the winding mechanism is in the second position, the cord will retract into the housing until the catch104contacts the stop or stopper108such that the spool100will rotate less than 360 degrees before the catch contacts the stop and the stop is spring biased such that the stop will block one of the at least one catches when the ratchet teeth are disengaged with the housing teeth and the spool is rotating in a wind-up direction.

Now also referring toFIG. 6showing the lip40and groove42configuration near the aperture38defined by the housing12. The lip40and groove42mate to form a housing joint44resistant to dirt, debris and moisture. The present invention further includes a method of attaching two housing pieces of a tensioning device for use with a self-tensioning snow chain, wherein the method comprises the steps of providing a first and second housing piece12a,12b. One respective housing piece12bhas a lip40and the other respective housing piece12ahas a groove42such that the lip can be mated with the groove within a joint between the top and the bottom12a,12bof the housing12.

Now also referring toFIGS. 7A and 7Bshowing an assembled tensioning cord sub-unit134. A cord20is threaded through a grommet32and has a first knob128aand a second knob128b. The knobs128may be fitted to the cord20by crimping, melting, casting and the like. The cord20is threaded through the grommet32before both of the knobs128are fitted to the cord20, which permits the diameter of the grommet32to be smaller than the diameter of the knobs128, so that the grommet32may more closely fit the cord20, allowing the grommet to be more appropriately sized to limit the infiltration of dirt, debris and moisture into the housing12. The cord20is attached to the first connection member22that is connected to a hook18(shown in phantom) used for securing the tensioning device11to parts of the snow chain14.FIG. 7Bshows how the second knob128bfits into a recess46(partially shown) formed by a first piece22aand second piece22bof the first connection member22. The first and second pieces22aand22bare secured together around the second knob128bthat is tightly secured to the cord20. Rivets23are placed through rivet receiving openings25to secure first and second pieces22aand22btogether, although any other fasteners such as threaded screws, bolts and nuts, adhesives, double backed tape and the like could be used.

Referring now also toFIGS. 8A and 8B,FIG. 8Ais a sectional view showing the internal components when the actuating lever26is in the down position thereby allowing the ratchet spool100to be in the up position. When the ratchet spool100is in the up position, the catches104are clear of the stopper108thereby allowing the ratchet spool100to freely wind-up and tighten the cord20. In this mode, the ratchet spool100may only rotate in the wind-up direction, because the ratchet teeth102can fully engaged with the housing teeth118to limit rotation if an extending or wind-out force is applied to the cord20.

FIG. 8Bis a sectional view showing the internal components when the actuating lever26is in the up position thereby forcing the ratchet spool100to be in the down position. While the ratchet spool100is in the down position, the ratchet teeth102are disengaged from the housing teeth118. This allows the ratchet spool100to rotate freely in either direction. The catches104stop the ratchet spool100from fully rotating in the wind-up direction. As the ratchet spool100begins to rotate in the wind-up direction, the stopper108will block the next catch104it encounters, thereby preventing the ratchet spool100from further winding-up.

In the embodiment shown inFIGS. 8A through 9A, the ratchet teeth102and the housing teeth118are cut at an angle “a” of about 90 degrees to a horizontal plane perpendicular to a vertical axis of the ratchet spool and the housing. In alternate embodiments of the present invention, the ratchet teeth102and housing teeth118may be overcut or undercut. The teeth102,118may be undercut at an angle ranging from about 3 to about 30 degrees, preferably from about 10 to about 25 degrees more than a 90 degree angle to a horizontal plane b perpendicular to a vertical axis c of the ratchet spool and the housing, so that when the tensioning device11is in a wind-up mode and the cord is tugged outwardly, the more the ratchet teeth118will become engaged and resist the cord20being moved in the wind-out direction. In the most preferred embodiments, the teeth102,118are undercut at an angle a′ of about 20 degrees more than a 90 degree angle to a horizontal plane b perpendicular to a vertical axis c of the ratchet spool and the housing, as illustrated inFIG. 9B.

Now referring also toFIG. 10A,FIG. 10Ais a diagrammatic view of one embodiment of the present invention showing the preferred positioning of two, single tensioning devices11attached to a wheel16. In this embodiment, the tensioning devices11are approximately 180 degrees from each other and their respective cords20and hooks18extend in opposite directions.

Referring now also toFIGS. 10B and 10C,FIG. 10Bis a diagrammatic view of one embodiment of the present invention showing the preferred positioning of a single, tensioning device11′ attached to a first cord20and a second cord20athat each have their respective hooks18. In this embodiment, the tensioning device11′ is centered with the exterior of the wheel16to provide equal tension on the first cord20aand the second cord20bwhich extend parallel to each other.

FIG. 10Cis a diagrammatic view of one embodiment of the present invention showing the preferred positioning of a single, tensioning device11″ attached to a first cord20, a second cord20b, and a third cord20cthat each have their respective hooks18. The tensioning device11″ is centered with the exterior of the wheel16to provide equal tension on the first cord20a, the second cord20b, and the third cord20c, which extend approximately 120 degrees from each other.

Now referring also toFIG. 11Athat shows another embodiment of the tensioning device of the present invention wherein the tensioning device11′ tensions a first cord20aand a second cord20b. Referring now also toFIG. 11B, which shows another embodiment of the tensioning device11′ of the present invention, wherein the tensioning device11″ applies tension to a first cord20a, a second cord20band a third cord20c.

Now referring also toFIG. 12A,FIG. 12Ais a perspective view of one embodiment an alternate ratchet spool100′ of the present invention showing the ratchet spool100′ configuration of having a first cord20aand a second cord20bthat are attached to the ratchet spool100′ and wound in the channel124. In this embodiment, only two catches104are on the under surface132of the ratchet spool100′, because less space is available. The first cord20aand second cord20bhave a first knob128afitted to their respective ends sized to fit snuggly into the ratchet spool recess130to prevent the first cord20aand the second cord20bfrom being pulled off of the ratchet spool100′.

Referring now also toFIG. 12B,FIG. 12Bshows a perspective view of an embodiment of the present invention showing a further alternate ratchet spool100″ configuration having a first cord20a, a second cord20b, and a third cord20c.

Referring now toFIGS. 13-16B, there is illustrated an alternate tensioning device11′″ having a housing12′″ having a housing top12a′″ and a housing bottom12b′″. There are holes29where rivets (not shown) will be inserted to attach the housing top12a′″ and the housing bottom12b′″ as in the other embodiments of the tensioning device. Located on the housing top12a′″ is a top button138. Additionally, on the side of the housing12′″ are a first side button136aand a second mirroring side button136b(not shown). Protruding from the housing12′″ is a grommet32from which a cord20(not shown) may pass.

FIG. 14shows an exploded view of the tensioning device11′″ shown inFIG. 13, but without the tensioning cord sub-unit134. A wave spring112sits on the inside of the housing bottom12b′″ and is positioned in a way to apply pressure to the ratchet spool100. A washer156is placed in between the wave spring112and the ratchet spool100. The tension spring110also rests inside the ratchet spool100and has a crimp122that can be inserted into a notch120(not shown) in the ratchet spool100, similar to that shown inFIG. 3, to secure the tension spring110to the ratchet spool100. The ratchet spool100has a channel124running around the outside of the ratchet spool100in the center and is sufficiently wide and deep enough for a cord20(not shown) to be wound around the rachet spool100within the channel124. On the top of the ratchet spool100are ratchet teeth102. The ratchet teeth102engage with the housing teeth118(not shown). In addition, there is a pawl152, connected to each of the side buttons136, having a pivot point150. The side buttons136are spring loaded with a pawl spring154. As seen inFIGS. 16A and 16B, the ratchet teeth102engage with the housing teeth118(not shown) located in the housing top12a′″ when the top button138is in the up position. When the top button138is in the up position, the ratchet spool100can only move in the wind-in direction to tighten the cord20(not shown). In this mode, the side buttons136are pushed into the housing12′″. When the top button138is in the down position, the ratchet spool100may move in either the wind-in or the wind-out direction. In this mode, the side buttons136are pushed out of the housing12′″ by the force of the spring154.

Referring now also toFIG. 15, showing the positioning of the top button138and the side buttons136when the top button138is in the up position. Here, the side buttons136are pushed into the housing12′″. Two button springs154rest against the interior of the housing top12a′″ and apply pressure to move the side buttons136out of the housing12′″. However, the side buttons136do not move out of the housing because the pawls152are stopped by the top button138. When the top button138is pushed down, the pawls152are no longer blocked and the side buttons136will pop out of the housing12′″. When housing teeth118are not in contact with the ratchet teeth102(not shown), the ratchet spool100(not shown) can rotate freely.

Referring now also toFIGS. 16A and 16B,FIG. 16A, shows the arrangement of the side buttons136, the top button138, the ratchet teeth102, and the housing teeth118when the top button138is in the up position. When the top button152is in the up position, the pawls152engage with the ratchet teeth102and the ratchet spool100can only move in the wind-up direction. In this view, for clarity, the wave spring112is not shown.

Referring now also toFIG. 16B, illustrating the arrangement of the top button152, the ratchet teeth102, and the housing teeth118when the top button138is in the down position. As the top button138gets pushed into to the down position, the force created by the button springs154(seeFIGS. 14 and 15) snaps the pawls152away from the ratchet teeth118so that the ratchet spool100can move in the wind-in or wind-out direction. To switch modes and prevent the ratchet spool100from rotating in the wind-out direction, the user presses the side buttons136back into the housing12′″ to force the top button138back up and allow the pawls152to again come into contact with the ratchet teeth118. In this view, for clarity, the wave spring112is not shown.