Patent Publication Number: US-2016229240-A1

Title: Anti-skid device for tire

Description:
TECHNICAL FIELD 
     The present invention relates to an anti-skid device for a tire, and more particularly, to an anti-skid device for a tire that, is mounted on a tire for stable driving on a snowy road or an icy road. 
     In general, chains, integrated, chains connected through a cable or a urethane block, snow tires, spike tires, and the like, are used to prevent skid of a vehicle on a snowy road or an icy road. 
     The chains or integrated chains are very difficult and complicated to mount became it is required to move them forward/backward m order to mount them. Even if an adult man mount them, it is very difficult to correctly mount them in a cold winter day. Accordingly, the chains are separated from a wheel and cause an accident while a vehicle is driven, or they may be damaged even into a non-reusable state. 
     Further, it is difficult to quickly change the snow tires or the spike tires on a mad under sudden change in weather condition, so the driver has to dangerously drive to a car mechanic to change the tires. Further, the tires are expensive and reduce fuel efficiency, so it is not economical. 
     Due to these defects, recently, anti-skid devices for a tire that are coupled to tires from a side have been increasing used. 
       FIG. 1  is art exploded perspective view illustrating a process of mounting an anti-skid device for a tire known in the art to a tire. 
     The anti-skid device for a tire includes a fixed plate  20  that is fixed to a wheel W of a tire T by an adapter  10 , a support plate  30  that has a plurality of anti-skid arms  40 , and a locking plate  50  that fixes the support plate  30  to a side of the wheel W of the tire T. 
     The adapter  10 , which is a part coupled to a side of the wheel W of the tire T to fix the fixed plate  20  to the tire, includes a special nut  11  with nut holes  11   a  and  11   b  at both ends, a fixing clip  12  composed of a clip  12   a  and a cap  12   b,  a long nut  13  with a bolt portion  13   a  and a nut hole  13   b  at both ends, and a short nut  14  with a bolt portion  14   a  and a nut hole  10   b  at both ends. 
     The adapter  10  selectively couples the special nut  11  or the fixing clip  12  and selectively connects the long nut  13  or the short nut  14  to the special nut  11  or the fixing clip  12 , in accordance with wheel bolts B or outs N coupled to the outer side of the wheel W. 
     Thereafter, the fixed plate  20  is fixed by inserting and tightening a bolt  16  into the nut hole  13   b  or  14   b  of the long nut  13  or the short nut  14  from the outside with the fixed plate  20  is disposed in position. In this process, washers  15  made of synthetic resin or metal may be interposed. 
     The anti-skid device is completely mounted, as described above, by mounting the support plate  30  coupled to the anti-skid arm  40  on the tire W, with the fixed plate  20  fixed to the wheel W, and coupling the locking plate  50  to the fixed plate  20  at the center of the support plate  30  so that the support plate  30  is fixed. 
       FIG. 2  is a cross-sectional view illustrating the coupling of the support plate  20  and the locking plate  50  in the anti-skid device for a tire illustrated in  FIG. 1 . 
     Referring to  FIG. 2 , the fixed plate  20  has steps  22  protruding toward the outside of a vehicle and circumferentially arranged with regular intervals around the inside of an insertion hole formed at the center portion, and has a plurality of fixing holes  25  through the plate to be coupled to tires W having various sizes by the adapter  10 . 
     The locking plate  50  is fitted in the fixed plate  20  with the support plate  30  therebetween, has a circular protrusion  51  inserted in the insertion hole of the fixed plate  20 , and has stoppers  52  that are formed around the circular protrusion  51  and are inserted into the spaces between the steps  22  of the fixed plate  20  and locked to the lower ends of the steps  22  when they are turned. Further, the locking plate  50  further has a restricting member  56  that is inserted in the center of the locking plate  50  and prevents rotation of the locking plate  50  by blocking the space between the steps  22  of the fixed plate when the locking plate  50  is turned to the fixed position. 
     However, when the anti-skid device is mounted in this way, the anti-skid device may be unlocked and separated from a tire while a vehicle is driven. When a vehicle equipped with the anti-skid device is driven on an uneven road, a large gap is generated between the anti-skid device and a tire, so the stoppers  52  of the locking plate  50  are damaged and the fixed plate  20  and the locking plate  50  are separated due to shock by the gap, so the anti-skid device is unlocked and separated from the wheel. 
     Such separation of an anti-skid device is generated while a vehicle is driven, so the separated anti-skid device interferes with the operation of the wheel, and it is likely to cause an accident. 
     DISCLOSURE 
     Technical Problem 
     The present invention has been made in an effort to solve these problems and an object of the present invention is to provide an anti-skid device for a tire that can prevent an anti-skid device for a tire from being damaged and separated by shock while a vehicle is driven. 
     Another object of the present invention is to pro vide an anti-skid device for a tire that can reduce shaking of an anti-skid device by fixing a support plate in close contact with a fixed plate and that can reduce vibration or noise that is generated when a vehicle equipped with an anti-skid device for a tire runs on a snowy road or an icy road. 
     Technical Solution 
     The present invention provides an anti-skid device for a tire that is fixed to a tire of a vehicle. The device includes: a fixed plate that is fixed to a wheel of a tire, has a cylindrical nut-type fastening portion protruding toward the wheel of the tire at a center portion and having a thread on the inner side, and has a plurality of fixing holes for fixing to the wheel on the surface; a support plate having a disc body having an insertion hole at the center portion and a plurality of coupling plates protruding radially around the outer side of the body; anti-skid arras that have a fastening portion coupled to the coupling plates and a contact portion, having a plurality of spikes on the outer surface that bends at an end of the fastening portion, and comes in contact with a road surface when being fastened to the tire: and a locking plate that protrudes on the bottom of a disc body, has a bolt-type fastening portion fastened to the nut-type fastening portion, and that is fixed with the body of the support plate between the bottom of the body and the fixed plate, in which threads for fastening the locking plate to the fixed plate by turning the locking plate in a direction in which the tire is rotated to drive a vehicle forward are formed on the nut-type fastening portion and the bolt-type fastening portion. 
     According to the present invention, a grip for a user to hold the locking plate is formed on the top of the body of the locking plate, and a tool groove where an insertion of a tightening tool for tightening the locking plate is inserted is formed at a center portion on the top of the body of the locking plate, so a user can insert the insertion of the tightening tool into the tool groove and tighten, the locking plate by turning the tightening tool using a handle. 
     According to the present invention, a first prominence-depression is formed around the nut-type fastening portion on the surface of fixed plate, and a disc portion that protrudes downward, covers the bolt-type fastening portion, and has a first counter-prominence-depression that coupled to the first prominence-depression thereon is disposed on the bottom of the locking plate. Herein, the first prominence-depression is composed of a plurality of projections radially extending with regular intervals on at least a portion of a surface around the nut-type fastening portion of the fixed plate, and the first counter-prominence-depression is composed of a plurality of grooves radially extending with regular intervals on the surface of disc portion for receiving the plurality of projections of the first prominence-depression. 
     According to the present invention, a first prominence-depression is formed around the nut-type fastening portion on the surface of the fixed plate, and a disc portion made of an elastic material, protruding downward to cover the bolt-type fastening portion, and corresponding to the first prominence-depression is disposed on the bottom of the locking plate. 
     According to the present invention, second prominence-depression is formed on a surface around the insertion hole of the body of the support plate, and a second counter-prominence-depression coupled to the second prominence-depression is formed on the bottom of the body of the locking plate. Herein, the second prominence-depression is composed of a plurality of projections radially extending with regular intervals, and the second counter-prominence-depression is composed of a plurality of grooves radially extending with regular intervals on the bottom of the body for receiving the projections of the second prominence-depression. 
     According to the present invention, a second prominence-depression is formed on a surface around the insertion hole of the body of the support plate, and an elastic plate made of an elastic member to correspond to the second prominence-depression is disposed on the bottom of the body of the locking plate. 
     According to the present invention, a convex band protrudes at both edges of the inner side of the contact portion of the anti-skid arm, an anti-torsion reinforcing band is formed from the contact portion to the fastening portion at the center portion of the inner side of the contact portion between the convex bands at both sides, and a plurality of toenails protruding at predetermined distances is formed at the convex bands at both sides. 
     Advantageous Effects 
     According to the present invention, an anti-skid device is fixed to a tire by a bolt-type fastening portion of a locking plate and a nut-type fastening portion of a fixed plate that are thread-fastened to each other. The bolt-type fastening portion can efficiently resist shock transmitted through the fixed plate, unlike stopper of locking plates of the related art, so it is possible to preclude the phenomenon that stoppers on a locking plate are damaged by shock and an anti-skid device is separated while a vehicle is driven as in the related art. Accordingly, stability is improved. 
     Further, according to the present invention, the locking plate can be fixed by thread-fastening to the fixed plate with a support plate therebetween. Accordingly, it is possible to reduce shaking of an anti-skid device, so it is possible to reduce vibration and noise generated while a vehicle equipped with an anti-skid device is driven on a snowy road or an icy road. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view illustrating a process of mounting an anti-skid device for a tire known in the art to a tire. 
         FIG. 2  is a cross-sectional view illustrating the coupling of a support plate and a locking plate in the anti-skid device for a tire illustrated in  FIG. 1 . 
         FIG. 3  is a perspective view when the anti-skid device, for a tire according to the present invention is mounted. 
         FIG. 4  is a perspective view illustrating a fixed plate of the anti-skid device for a tire according to the present invention. 
         FIG. 5  is a perspective view illustrating a support plate of the anti-skid device for a tire according to the present invention. 
         FIGS. 6 and 7  are a perspective view and a plan view rotary disc of the anti-skid device for a tire according to the present invention. 
         FIGS. 8 and 9  are an exploded perspective view and a cross-sectional view illustrating the coupling of a pair of coupling plates, a rotary disc, and anti-skid arms of the support plat of the anti-skid device for a tire according to the present invention. 
         FIGS. 10 and 11  are an exploded perspective view and a cross-sectional view illustrating the coupling of other coupling plates and the anti-skid arm of the support, plate of the anti-skid device for a tire according to the present invention. 
         FIGS. 12 and 13  are a perspective view and a plan view illustrating the anti-skid arm of the anti-skid device for a tire according to the present invention. 
       PIGS.  14  and  15  are perspective views illustrating the upper portion and the lower portion of the locking plate of the anti-skid device for a tire according to the present invention. 
         FIGS. 16 and 17  are a perspective view and a cross-sectional view of a fixed plate according to another embodiment of the present invention. 
         FIG. 18  is a perspective view illustrating a support plate according to another embodiment of the present invention. 
         FIGS. 19 and 20  are perspective views illustrating the upper portion and the lower portion of a locking plate according to another embodiment of the present invention. 
         FIG. 21  is a partial cross-sectional view illustrating an anti-skid device for a tire according to another embodiment of the present invention. 
     
    
    
     BEST MODE 
     Embodiments of the present invention are described hereafter in detail with reference to the accompanying drawings. 
     An anti-skid device for a tire according to the present invention includes a fixed plate  200 , a support plate  300 , anti-skid arms  400 , and a locking plate  500 . 
     The fixed plate  200  is fixed to a wheel W of a tire T by an adapter  10  (see  FIG. 1 ). 
     Referring to  FIG. 4 , the fixed plate  200  of the present invention has a cylindrical nut-shaped fastening portion  240  having a thread  244  around the inner side at the center and protruding toward a tire wheel from the center. A holt-type fastening portion  540  of the locking plate  500  is thread-fastened to the nut-type fastening portion  240  of the fixed plate  200 . The fixed plate  200  is classified for a left tire or a right tire in accordance with the position of the tire where the fixed plate  200  is mounted and the thread  244  is formed on the nut-type fastening portion  240  of the fixed plate  200  so that the locking plate  500  is fastened when it is rotated in the rotational direction of the tire when a vehicle is drives forward. 
     A plurality of fixing holes  250  is formed through the surface  210  of the fixed plate  200 . The fixing holes  250  correspond to the positions of wheel bolts on tires having various sizes when the fixed plate  200  is fixed to the wheel of a tire T by an adapter. Accordingly, the fixed plate  200  can be fixed to the wheel W of the tire T by mounting an adapter on the wheel of a tire, selectively inserting a bolt into a fixing hole  250  corresponding to the position of the adapter, and fastening the fixed plate to the adapter. 
     Referring to  FIGS. 5 to 13 , the support plate  300  according to the present invention has a disc body  310  having a surface stepped inward and extending from a ring-shaped stepped portion  302 , and a plurality of coupling plates  320   a  and  320   h  protruding, radially, arranged with regular intervals around the outside of the body  310 , and allowing detachable attachment of the anti-skid arms  400 . 
     The body  310  has an insertion hole  315  at the center. The insertion hole  315  is a passage through which the bolt-type fastening portion  540  of the locking plate  500  is inserted to he fastened to the nut-type fastening portion  240  of the fixed plate  200 . 
     The coupling plates  320   a  to  320   h  radially protrude around the outer side of the body  310  of the support plate  300 . The coupling plates  320   a  to  320   h  are parts where the anti-skid arms  400  are detachably coupled, and rotation holes  321   a  and  321   b  to which the rotary discs  330   a  and  330   b  are rotatably coupled are formed through a pair of adjacent coupling plates  320   a  and  320   b.    
     A plurality of fitting-adjustment holes  333   c  to  331   h  spaced with regular intervals is formed in the other coupling plates  320   c  to  320   h  except for the coupling plates  320   a  and  320   b  having the rotation holes  321   a  and  321   b  so that the ends of the anti-skid arms  400  cats be fitted. 
     The rotary discs  330   a  and  330   b  are rotatably disposed in the rotation holes  321   a  and  321   b  formed on the pair of adjacent coupling plates  320   a  and  320   b  and has a plurality of fitting-adjustment holes  331   a  and  331   b  spaced with regular intervals so that the ends of the anti-skid arms  400  can be fitted. 
     Further, upper and lower stoppers  322   a  and  332   b  alternately protruding are formed around the outer sides of the upper and lower ends of the rotary discs  330   a  and  330   b  so that, they are locked to the upper and lower sides of the coupling plates  320   a  and  320   b  to prevent separation from the rotation holes  321   a  and  321   b.    
     The rotary discs  330   a  and  330   b  coupled to the anti-skid arms  400  are rotatably coupled to the pair of coupling plates  320   a  and  320   b,  so it is possible to install the anti-skid device without interference between the anti-skid arms  400  and the contact portion between the tire and the road surface by opening a pair of anti-skid arms  400  coupled to the pair of rotary plates  330   a  and  330   b  when the device is mounted on the tire. 
     Further, the other anti-skid arms  400  are coupled to the other coupling plates  320   c  to  320   h  without notation, so it is possible to prevent rotation of the anti-skid device for a tire with respect to the tire while a vehicle is driven on a snowy road or an icy road. 
     Meanwhile, since the plurality of fitting-adjustment holes  331   a  to  331   h  are formed at the other coupling plates  320   c  to  320   h  and the pair of rotary plates  330   a  and  330   b  to which, the anti-skid arms  400  are coupled, the anti-skid arms  400  can be selectively coupled to tit to the size of tires. 
     The anti-skid arms  400  each have a fastening portion  410  detachably coupled to the fitting-adjustment holes  331   a  to  331   h , and a contact portion  420  vertically bending at an end of the fastening portion  410  and coming in contact with a road surface when being mounted on a tire. 
     The fastening portion  410  is brought in close contact with a side of a tire, and has a coupling step  415  at an end that is locked to the fitting-adjustment holes  331   a  to  331   h  when it enters a stable state after being inserted in the fitting-adjustment holes  331   a  to  331   h.    
     The contact portion  420  is brought in close contact with the outer side of the tire T. A plurality of conical spikes  421   a  to  421   d  is mounted in a zigzag shape on the outer side of the contact portion  420  (on the portion coming in contact with a road surface) to increase a friction force on a snowy road, and an icy road. 
     The spikes  421   a  to  421   e  has a holders  424   a  to  424   e  formed on the contact portion  420  to partially cover the spikes and contact with a road surface is minimized by the conical shape of the spikes  421   a  to  421   e , so damage to the road surface can be minimized. 
     Further, reinforcing ribs  425  protruding outward on the outer side of the contact portion  420  and at least partially connecting the spikes  421   a  to  421   e  are further formed to increase strength of the entire contact portion  420  and increase the friction, force on a snowy road and an icy road. 
     A U-shaped groove  427  is formed at the end of the contact portion  420  to improve a ground-contact force on a snowy road. 
     Further, a convex bands  423  that protrude may be further formed at both edges of the inner side (the portion coming in contact with the outer side of the tire) of the contact portion  420  to increase coupling force to the tire. 
     Further, a plurality of toenails  422  protruding and spaced each other is formed on both convex bands  423 . The toenails  422  formed on both convex bands  423  allow the anti-skid arms  400  to hold the outer side of a tire, so they prevent spin between the tire and the anti-skid arms. 
     Meanwhile, an anti-torsion reinforcement band  426  is formed from the contact portion  420  to the fastening portion  410 , at the center of the inner side of the contact portion  420  (see  FIG. 11 ). 
     Referring to  FIGS. 14 and 15 , the locking plate  500  according to the present invention, has a disc body  510  and a bolt-type fastening portion  540  protruding on the bottom of the body  510 . The bolt-type fastening portion  540  is fastened to the nut-type fastening portion  240  of the fixed plate  200 . 
     A thread  544  is formed around the outer side of the bolt-type fastening portion  540  of the locking plate  500 . The thread  544  is formed in a direction in which fastening is made when the locking plate  500  is rotated in the direction in which the tire equipped with the anti-skid device is rotated to drive a vehicle forward. When a vehicle is driven forward, the right tire is rotated clockwise and the left tire is rotated counterclockwise. Accordingly, a right thread is formed on the bolt-type fastening portion  540  of the locking plate  500  for an anti-skid device for a tire that is mounted on a right tire and a left thread is formed on the bolt-type fastening portion  540  of the locking plate  500  for an anti-skid device for a tire that is mounted on a left tire. Further, the threads  244  of the nut-type fastening portions  240  of the fixed plates  200  that are coupled to the locking plates  500  are formed in the corresponding directions. 
     Accordingly, it is possible to thread-fasten the holt-type fastening portion  540  of the locking plate  500  and the nut-type fastening portion  240  of the fixed plate by rotating the bolt-type fastening portion  540  of the locking plate  500  in the same direction as the rotation direction of a tire when a vehicle is driven forward. 
     The locking plate  500  is fastened to the fixed plate  200  by a tightening tool  600  (see  FIG. 19 ), with the support plate  300  having the anti-skid arms  400  between the locking plate and the fixed plate  200 . The locking plate  500  receives a force in the locking direction by inertia every time braking is performed while a vehicle is driven forward, so the locking plate  500  can keep being coupled to the fixed plate  200  by a strong fixing force without separating while the vehicle is driven. That is, according to the present invention, by using the fact that a rapid change in speed of a tire while a vehicle is driven is made every time braking is performed while the vehicle is driven. forward, the locking plate  500  is tightened by torque in the locking direction to the fixed plate  200  by inertia in every braking, so the fixing force for the locking plate  500  can be kept strong. 
     A grip  520  allowing a user to hold and turn the locking plate  500  is formed on the top of the disc body  510  of the locking plate  500 , and a hexagonal tool groove  525  is formed at the center portion of the disc body  510 , that is, at the center portion of the grip  520 . The tool groove  525  is provided for a user to fix the locking plate by strongly turning the locking plate  500 , using a tightening tool  600  (see  FIG. 19 ), after temporarily locking the locking plate  500  with a hand. 
     Referring to  FIG. 19 , the tightening tool  600  has a hexagonal insertion  620  that is inserted into the tool groove  525  at the lower end of a tool body  610 , and a handle  630  extending from the side of the tool body  610 . It is possible to tighten the locking plate  500  to the fixed plate  200  with the support plate  300  therebetween, by inserting the insertion  620  into the tool groove  525  and then turning the tightening tool  600  with a hand holding the handle  630  to turn the locking plate  500 . 
     Referring to  FIG. 15 , a disc portion  530  protruding downward and covering the bolt-type fastening portion  540  at the center portion is disposed on the bottom of the disc body  510  of the locking plate  500 . The disc portion  530  is in close contact with the top of the fixed plate  200 . 
       FIGS. 16 to 21  illustrate another embodiment of an anti-skid device for a tire according to the present invention, that is, illustrate another embodiment of the fixed plate  200 , support plate  300 , and locking plate  500 . 
     Referring to FIGS,  16  and  17 , the fixed plate  200  according to another embodiment of the present invention further includes a first prominence-depression  220  around a nut-type fastening portion  240  on the surface. 
     The first prominence-depression  220  may be composed of a plurality of projections extending radially with regular intervals around the nut-type fastening portion  240 . Although the projections are exaggerated in the drawings for the convenience of understanding, they have a height and width that do not interfere with fixing the locking plate  500  when the locking plate  500  is locked to the fixed plate  200  by the tightening tool  600 . 
     When the first prominence-depression  220  is composed of a plurality of projections, they may be formed only in a predetermined area on the surface around the nut-type fastening portion  240  in consideration of the position of the fixing holes  250 . For example, they may be formed with regular intervals around the nut-type fastening portion  240  at positions that do not overlap the fixing holes  250 . 
     The first prominence-depression  220  prevents the locking plate  500  from being unlocked by increasing a friction force in contact with a first counter-prominence-depression  535  of the locking plate  500 . 
     Referring to  FIG. 18 , the support plate  300  according to another embodiment of the present invention further includes a second prominence-depression  316  on the surface around an insertion hole  315  of a body  310  to increase a friction force in contact with the locking plate  500 . 
     According to another embodiment of the present invention, the second prominence-depression  316  may be composed of a plurality of projections radially extending with regular intervals around the insertion hole  315 . Although the projections are exaggerated in the drawings for convenience of understanding, they have a height and width that do not interfere with fixing the support plate  300  by the locking plate  500  when the locking plate  500  is locked to the fixed plate  200  by the tightening tool  600 , with a bolt fastening portion  540  of the locking plate  500  inserted in the insertion hole  315 . 
     Referring to  FIGS. 19 and 20 , the locking plate  500  according to another embodiment of the present invention includes the first counter-prominence-depression  535  that is coupled to the first prominence-depression of the fixed plate  200 , on the surface of a disc portion  530 . The first counter-prominence-depression  535  prevents unlocking by increasing a friction force in contact with the first prominence-depression  220 . 
     When the first prominence-depression  220  is composed of a plurality of projections, the first counter-prominence-depression  535  may be composed of a plurality of grooves radially formed with regular intervals to correspond to the projections. 
     Further, according to the present invention, the disc portion  530  may be made of an elastic material having elasticity such as rubber. When the disc portion  530  is made of an elastic material, it increases a friction force by combining with the first prominence-depression  220  by elastic deformation. In this case, the disc portion  530  may selectively have the first counter-prominence-depression  535 . 
     A second counter-prominence-depression  515  is formed on the bottom of the disc body  510 , that is, on the outer surface of the disc  530 . The second counter-prominence-depression  515  prevents unlocking between the support plate  300  and the locking plate  500  by being coupled to the second prominence-depression  316  of the support plate  300 . 
     When the second prominence-depression  316  formed on the body  310  of the support plate  300  is composed of a plurality of projections, the second counter-prominence-depression  515  may be composed of a plurality of grooves radially extending with regular intervals to correspond to the projections. 
     According to another embodiment of the present invention, a ring-shaped elastic plate  514  made of an elastic material such as rubber may be further disposed on the bottom of the disc body  510  where the second counter-prominence-depression  515  is formed. The elastic plate  514  is coupled to the second prominence-depression  316  to increase a friction force by elastically deforming and may selectively have the second counter-prominence-depression  515 . 
       FIG. 21  is a cross-sectional view illustrating partial coupling of an anti-skid device for a tire according to another embodiment of the present invention. A process of installing the anti-skid device for a tire of the present invention is described with reference to  FIG. 21 . 
     First, the fixed plate  200  is fixed to a tire wheel by an adapter. The fixed plate may be mounted on a tire wheel when the anti-skid device for a tire is installed, and when there is a need for frequently install the anti-skid device for a tire in a season such as winter, a vehicle can be driven with the fixed plate fixed to a tire wheel in advance. In this case the vehicle can be driven with the fixed plate covered with a fixed cover (not illustrated) for the external appearance of the vehicle. 
     When it is required to drive on a snowy road or an icy road, a user separates the fixed cover from the fixed plate  200  and fits the support plate  300  coupled with a plurality of anti-skid arms  400  onto a tire, in which two anti-skid arms  400  coupled to the rotary discs  330   a  and  330   b  of the plurality of anti-skid arms  400  are brought in contact with the road surface and the device is mounted on a tire with the arms opened to both sides. 
     Next, the locking plate  500  is fixed to the fixed plate  200 , at the outside of the support plate  300 , in which the body  310  of the support plate  300  is positioned around the insertion hole  315  between the body  510  of the locking plate  500  and the fixed plate  200 . 
     In order to fix the locking plate, a user holds the grip  520  of the locking plate  500  with a hand and turns the locking plate  500  in the fastening direction so that the bolt-type fastening portion  540  is thread-fastened to the nut-type fastening portion  240  of the fixed plate  200 . Thereafter, the user inserts the insertion  620  of the tightening tool  600  into the tool groove  525 , holds the handle  630 , and turns the tightening tool  600  in the fastening direction of the locking plate  500 , thereby more firmly combining the locking plate  500  and the fixed plate  200 . 
     Accordingly, when a vehicle is equipped with the anti-skid device for a tire and driven on an icy road or a snowy road, the locking plate  500  continuously receives a force in the tightening direction while the vehicle is driven, so the locking plate  500  is not unlocked. 
     Meanwhile, the coupling between the first prominence-depression  220  of the fixed plate  200  and the first counter-prominence-depression  535  of the locking plate  500  and the coupling between the second prominence-depression  316  of the support plate  300  and the second counter-prominence-depression  515  of the locking plate  500  additionally support, each other, so the locking plate  500  can be more firmly maintained. 
     According to the present invention, as compared with anti-skid devices for a tire of the related art, the anti-skid device for a tire can be more firmly coupled, so vibration and noise can be reduced. Further, the coupled portions are not damaged, so it is possible to remove the danger of separation of the anti-skid device for a tire while a vehicle is driven. Therefore, stability is more improved. 
     Although embodiments of an anti-skid device for a tire of the present invention were described above, the present invention is not limited thereto and various changes and modification within the scope of the present invention described in claims and illustrated in the accompanying drawings should be construed as being included in the present invention.