Device for quickly fitting snow chains to vehicle tires

A tire chain assembly including two stays hinged at one end on a housing and supporting wall chains which hold tread chains in place on the tread of the tire when they are pulled tight as the stays are drawn together by a resilient linkage. Arms or resilient linkages control displacement and vibration of the stays when the wheel is moving. The device enables gripping equipment to be fitted quickly and easily and is suitable for use on snow-covered, muddy, sandy, or vegetation-covered terrain.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an improved device for installing snow 
chains on road vehicle tires. 
2. Description of Background and Relevant Information 
When the road is covered with snow, vehicle tires run the risk of skidding, 
which causes the driver to lose control of the vehicle. To prevent or 
limit the risks of skidding, tires have been provided with studs or tire 
treads comprising a very particular size and/or a tread rubber of very 
particular design; this technique is very efficient but requires a set of 
special tires for winter, because these tires cannot be used in summer 
and, in addition, they are inefficient on deep fresh snow. 
For occasional users, and those who may find themselves in heavy snow, 
commercially available devices include chains or notched bars for 
insertion between the tire and the snow. These devices include 
protuberances that become anchored in the snow, on the one hand, and the 
tire becomes attached to such protuberances, on the other hand. 
When the chains, which will be referred to hereinafter as "crosspieces" 1, 
as seen in FIG. 1, are used, they are substantially perpendicular to the 
tread 26 of the tire 18 such that they are each located in a plane passing 
through the axis of rotation of the wheel 27, and are position at regular 
intervals, if possible. The length of each crosspiece 1 is generally 
greater than the width 28 of the tire tread 26, and each of its ends 29 is 
connected on both sides of the tire 18, at the end 29 of the other 
crosspieces 1, by a connecting chain 8 referred to hereinafter as a "wall 
chain"; there is an outer wall chain 31 and an inner wall chain positioned 
on the other side 30 of the wheel 27 (seen in FIG. 2), i.e., on the side 
where the hub of the wheel 27 is attached. 
When the assembly is placed on the ground such that the crosspieces 1 (FIG. 
1) and the wall chains 8 are straight, one obtains a kind of ladder whose 
wall chains 8 form the side pieces, and the crosspieces 1, which generally 
have the same length, form the rungs. The assembly is wound around the 
tire 18 of the wheel 27 such that the crosspieces 1 are positioned on the 
tire tread 26, the middle of the crosspiece 1 coinciding substantially 
with the median of the tire tread 26. With the assembly placed on the tire 
in this manner, the wall chains 8, whose maximum length is about 15-20% 
less than the outer perimeter of the tire 18, are stretched. The 
crosspieces 1 are positioned by degrees such that they are located 
substantially in planes passing through the axis of the wheel 27, and the 
two ends 4 and 5 of each wall chain 8 are fastened by an appropriate 
device by adjusting the chain to a suitable length so that it is 
stretched. French Patent Publication No. 2 630 972 discloses a snow chain 
of this type. 
In practice, it is difficult to have access to the rear portion 30 (FIG. 2) 
of the wheel 27, located on the side of the hub attachment point, to 
fasten the wall chain. If the assembly is positioned so as to first cover 
the upper portion of the wheel, the attachment zone of the ends 4 and 5 of 
the wall chains 8 is located next to the ground. The length for contact of 
the tire tread 26 with the ground, in this area, by construction being 
greater than the distance between two crosspieces 1 in succession, it is 
impossible to correctly fasten the ends 4 and 5 of the wall chain 8, it is 
accordingly recommended, at that time, to position the snow chain flat as 
previously described to allow the car to ride thereon, and to then proceed 
with the closure of the wall chains 8. Placing the assembly on the tire by 
this procedure requires that numerous operations be carried out in a 
predetermined order. Moreover, preliminary training is necessary to 
perform this operation correctly. 
To simplify the positioning of the anti-skid device on the tires, the 
crosspieces have been replaced in other applications by notched rungs 
placed perpendicularly to the tire tread and connected to rods that are 
substantially perpendicular to the bars and oriented substantially towards 
the center of the wheel. The rods are connected to one another, in the 
vicinity of the wheel, by an element comprising a mechanism that makes it 
possible to adjust the length of the rods such that the bar assembly is 
tightened on the tire. At that time, it is no longer necessary to have 
access to the rear of the wheel to position the device. This type of 
assembly, which provides an elegant technical solution to the problem, has 
the disadvantage of being mechanically more complex and, therefore, more 
expensive. Further, it had to be abandoned because it was damaging the 
suspension and the transmission on the vehicles. 
There is a derived system, according to the device disclosed in European 
Patent Publication No. 0 312 636, that enables the attachment of the 
chains. This system comprises notched rungs attached to two wall chains, 
which themselves are attached at four points located on the tire tread. 
The wall chains are inserted at the same time as the rungs between the 
tread and the ground. The four attachment points are connected by a device 
journalled to arms forming substantially a cross centered on the wheel 
axis; the connecting element maintaining the arms is fastened to the wheel 
rim by means of elastic attachments, with respect to which the connecting 
element can pivot about an axis parallel to the wheel axis to enable the 
attachment points of the chains to rotate with respect to the elastic 
attachment. This device has the disadvantage of being delicate to position 
on the wheel. U.S. Pat. No. 3,242,963 discloses a snow chain comprising 
crosspieces maintained in place on the tire tread by wall chains. These 
chains are stretched by means of stays associated with one arm, the 
tensioning being ensured by an air jack that tends to bring said stays 
closer together, 
SUMMARY OF THE INVENTION 
The present invention has an object of proposing a nonskid device that has 
the advantage of being simple, and easy to mount on the tire without 
particularly displacing the car. In particular, it enables the centering 
and the tensioning of the assembly in a single movement. 
The present invention is accordingly a chain assembly for vehicle wheels. 
Preferably, the chain assembly is a snow chain assembly. 
The chain assembly of the present invention comprises a plurality of 
driving surface-contacting members to be maintained on tire tread. 
Preferably, the driving surface-contacting members are crosspieces. 
The chain assembly of the present invention further comprises a wall chain 
subassembly, The wall chain subassembly comprises an inner wall chain to 
be positioned on the side of the wheel opposite to that taken by the 
individual installing the chain assembly, and an outer wall chain to be 
positioned on the same side of the wheel as that taken by the individual 
installing the tire chain, 
The chain assembly of the invention further comprises two L-shaped stays 
for tensioning the wall chain subassembly on both sides of the wheel. Each 
of the two L-shaped stays comprises both a horizontal portion of the 
L-shape, to which the wall chain subassembly is directly or indirectly 
fixed, and also a vertical portion of the L-shape, which comprises a 
hooking or attachment point. 
The chain assembly of the invention further comprises a common connection 
element on which each of the two L-shaped stays is journalled, by its 
vertical portion of the L-shape, about a separate axis of rotation. When 
the chain assembly is assembled on the vehicle wheel, the common 
connection element is located in the vicinity of the wheel axis on the 
same side of the wheel as the outer chain. 
The chain assembly of the invention further comprises a first elastic link 
for tensioning the chain assembly when the chain assembly is assembled on 
the vehicle wheel. The first elastic link comprises ends to be fixed to 
the L-shaped stays at the attachment points. 
The chain assembly of the invention further comprises at least two arms, 
each of which is fixed at one end to the outer wall chain, and also 
journalled at the other end on the common connection element, by a 
separate axis of rotation. The axes of rotation for the at least two arms 
are substantially parallel to the axes of rotation for the two L-shaped 
stays. 
The chain assembly of the invention further comprises at least one second 
elastic link. The at least one elastic link comprises three attachment 
points for connecting between the two L-shaped stays, and also between the 
outer wall chain and the two L-shaped stays. The first attachment point is 
for attachment to the outer wall chain, and is located in the bisecting 
plane of the angle formed by the two L-shaped stays, when the chain 
assembly is assembled on the wheel. Each of the second and third 
attachment points is connectable to the vertical portion of the L-shape of 
an L-shaped stay.

DETAILED DESCRIPTION OF THE EMBODIMENTS 
The invention resides in a device for tensioning the previously described 
wall chains 8, shown in FIG. 1, especially when they are associated with 
crosspieces 1; but the device is also suitable where the crosspieces 1 are 
replaced by known systems that are more complex, such as those that use a 
crossed arrangement of chains for insertion between the tire 18 and the 
ground or a frame, without these examples being limiting. For clarity of 
the disclosure, only the example using crosspieces 1 will be considered, 
it being understood that all of the systems susceptible of being attached 
by wall chains 8 fall within the scope of this invention. 
The device for tensioning the wall chains 8 (FIG. 1) is constituted by two 
"L"-shaped stays 32. The portion 6 and 7 of each stay corresponding to the 
vertical portion of the "L" has a length on the order of the radius of the 
tread 26 of the tire 18; the top of the "L" of each portion 6 and 7 of the 
stay 32 is journalled on a connecting piece 11 that is referred to 
hereinafter as the housing 11. 
The housing is mainly formed of two parallel flanges 38 and 39 crossed by 
the journal axes of the stays 32; the stays 32 are journalled on the 
housing 11, respectively, along an axis 10 and an axis 9 that are parallel 
to the axis 34 (FIG. 2) of the wheel 27, when the snow chain (FIG. 1) is 
in place on the wheel. Housing 11 enables a movement of the stays 32 about 
their respective axes 9 and 10 from a position where they are parallel and 
side by side to a position in which the stays 32 (PIG. 2) are preferably 
in the extension of one another. 
Of course, the portion 6 and 7 of each stay 32 corresponding to the 
vertical portion of the "L" has a shape that makes it possible to move the 
housing 11 away from the center of the rim 33 of the wheel 27 over a 
sufficient distance so that it is not disturbed by the shape of the latter 
33 when the tensioning device is positioned. The portion 2 and 3 of each 
stay corresponding to the horizontal portion of the "L" is substantially 
parallel to the axis 34 of the wheel 27, when the tensioning device is 
positioned, and is pressed across the tread 26 of the tire 18, the shape 
of which it assumes substantially; its length is determined as a function 
of the width of the tire and can vary as indicated in FIG. 5, FIG. 6 and 
FIG. 7. In the preferred version of the invention, the length is such that 
the end of the stays does not stick out of the tire 18 on the inner side 
of the wheel, as indicated in FIG. 5 or FIG. 7. When the stays 32 rotate 
about journals 9 and 10, their ends 2 and 3 corresponding to the 
horizontal portion of the "L" remain parallel, and their maximum spacing 
during the movement must be greater than the outer diameter of the tire 
18, as shown in FIG. 2. 
The ends 4 and 5 of the outer wall chain 31 are permanently fixed on the 
portions 6 and 7 of the stays 32 Each of the ends of the inner wall chains 
located on the side 30 (FIG. 2) of the wheel 27, is permanently fixed in 
the vicinity of the end 36 of the corresponding stay 32, i.e., in the 
vicinity of the end 36 of the horizontal portion of the "L". 
The tensioning of the wall chains 8 (FIG. 1) is done by bringing the stays 
32 closer together, under the action of springs or rubber bands 23 
stretched between the two stays 32, between attachment points 24 and 25 
located in the zones 6 and 7 of the stays 32, so that there is a tendency 
to close the angle 37 that they create between them. Since the wall chains 
8 are stretched, the crosspieces are stretched as described previously. 
During operation, the deformations of the tire 18 cause the stays 32 to 
oscillate in a plane parallel to the axis of rotation 34 (FIG. 2) of the 
wheel 27, and it is necessary to limit the movement thereof with respect 
to the rim 33. In a preferred version of the invention, the casing 11 
(FIG. 1) comprises two arms 12 and 13 journalled, at one of their ends, in 
the casing 11 along axes 16 and 17 substantially parallel to those 9 and 
10 of the stays 32, but positioned so as not to hinder the movement of the 
latter about their respective axes 9 and 10. The arms 12 and 13 are fixed 
to the outer wall chain 31 in the vicinity of ends 14 and 15, 
respectively, such that when the snow chain is positioned, they form, 
between them, an angle 40 greater than 120 degrees, open on the side 
opposite the opening of the angle 37 of the two stays 32 while having 
substantially the same bisector. When the outer wall chain 31 is stretched 
by the coming together of the stays 32, it constitutes a relatively fixed 
point for supporting the arm, which makes it possible to create a sort of 
triangle that allows the movement of the casing 11 to be limited. 
During operation, the casing 11 (FIG. 1) makes it possible to partially 
separate tie relative movements of the stays 32 under the action of the 
irregularities of the road and the deformation of the tire 18. Indeed, the 
stays 32 are displaced in a substantially radial direction with respect to 
the wheel 27, whereas the casing 11 oscillates about an axis of rotation, 
remaining substantially parallel to itself and to the axis 34 (FIG. 2) of 
the wheel 27, so as to compensate for the relative displacements of the 
two stays 32 (FIG. 1). This oscillation causes the displacement of the 
journal points of the arm 12 and 13 in a direction perpendicular to the 
general direction of the arms, which makes it possible to considerably 
limit the force on tie attachment of the ends 14 and 15, respectively, on 
the wall chain 31. In a preferred version of the invention, each of the 
ends 14 and 15 of the arms 12 and 13, fixed to the wall chain 31, 
comprises a flat support zone on the tire 18. 
The axes 16 and 17 of the arms 12 and 13 are preferably positioned on both 
Is sides of the axes of rotation 9 and 10 of the stays 32 so as not to 
hinder the movement of the stays 32 and to facilitate the folding of the 
snow chain when it is not in use. When the stays 32 are positioned 
parallel side-by-side, the arms 12 and 13 can then be brought back 
parallel to the stays 32 so that the assembly takes the least possible 
volume. 
The position of the arms 12 and 13 journalled by forming an angle 40 
greater than 120.degree. does not permit efficient dampening of the 
oscillations due to the radial displacement of them stays 32, under action 
of the centrifugal forces and of the irregularities of the road. To 
prevent this phenomenon, there can be placed, in the bisecting plane of 
the angle 37 formed by the stays 32, an elastic connection 19 connecting 
the stays 32. Elastic connection 19 is fixed to stays 32 at points 21 and 
22 of zones 6 and 7, and is fixed to the wall chain 31 in the area 20 
where it cuts such bisecting plane. 
If necessary, there can be added other arms for maintaining the casing 11 
and other flexible connections, elastic or not, between the stays 32 and 
the outer wall chain 31 without leaving the scope of the invention. 
The positioning of the snow chain is done in the following manner: the 
chain is positioned flat on the ground such that the portions 2 and 3 
(FIGS. 1, 2) of the stays 32, corresponding to the horizontal portion of 
the "L" are turned upwardly, and such that the stays 32 are substantially 
opposed and positioned parallel to the plane of the wheel 27 on which the 
chain must be placed. All of the wall chains 8, crosspieces 1, and arms 12 
and 13 are located on the side of the stays 32 opposite the wheel 27. The 
inner wall chain is grasped at a right angle to the attachment point 20 on 
the outer wall chain 31, of the elastic link 19 previously described to be 
located in the bisecting plane, and it is passed behind the upper portion 
of the tire 18. During this movement, the housing 11 is placed in the 
vicinity of the axis 34 (FIG. 2) of the wheel 27 and the stays 32 that are 
in the extension of one another come to cover the tire 18 through their 
ends 2 and 3 corresponding to the horizontal portion of the "L", whereas 
the portions 6 and 7 corresponding to the vertical portion of the "L" come 
into contact with 41 with the tire 18. The stays 32 (FIG. 1) are lowered 
towards one another under their own weights by pivoting about their 
respective axes 9 and 10, whereas the crosspieces 1 are correctly 
positioned with respect to their attachment points 29 corresponding on the 
wall chains 8. When everything is positioned, the stays 32 are affixed to 
one another by means of a stretched elastic link 23 that makes it possible 
to simultaneously stretch the crosspieces 1; the snow chain is then in 
position. 
In the preferred version of the application, the arms 12 and 13 position 
themselves when the stays 32 pivot to be positioned while the elastic link 
19 located in the bisecting plane is stretched. It is necessary to 
increase the tension of the elastic link 23 between the stays 32, to 
consider the act that the stays will be completely positioned as soon as 
the vehicle will pull up, in order to maintain a still sufficient tension, 
because the distance between them is, by construction, less than the 
length of the support zone of the tire on the road. 
To dismount the snow chain, it suffices to preferably place the wheel 27 in 
a position such that the stays 32 are not wedged between the tire tread 26 
and the grounds to untie the elastic link 23 which brings the two stays 32 
closer together, and to space the two stays 32 apart by pulling towards 
oneself so that the inner wall chain passes again above the tire tread 26 
to come on the outer side; the pulling is continued until there only 
remains the internal portion of the chain confined by the contact of the 
tire tread 26 with the ground. It suffices to move the vehicle forward to 
release the chain. It is still necessary to fold it by bringing the stays 
32 and, in the preferred version, the arms 12 and 13 such that they are 
positioned in parallel to one another to occupy a minimum space. 
In another variation of the invention, the arms 12 and 13 are replaced by 
the extension of one of the stays 32 beyond its axis of rotation 9 with 
respect to the housing which remains substantially at the level of the 
center of the wheel. This extension reaches up to the chain 31, to which 
the end of the stay extension is fixed. 
In a variation of the device, a non-elastic link 45, by sliding along the 
stays 42 which it encircles, and which are progressively spaced apart, 
makes it possible to perform the tensioning of the chains by playing on 
their flexibility. 
In a variation of the invention, there can be attached, against the outer 
side of the tire 46, a magnetic ring 47 fixed by springs 48 to the rim 49 
of the wheel. The stays 50 and possibly the arms 51 are pressed against 
the magnetic ring 47 and maintained in place by magnetic attraction at the 
time of installation. The positioning of these elements is thereby 
facilitated, and also their vibrations during movement are eliminated. 
In another variation of the invention, the end 52 (FIG. 8) of the stays 53, 
corresponding to the horizontal portion of the "L", is connected to the 
other portion 54 of the stay 53, by a journal 55 along an axis 
perpendicular to the general direction of the portion 54 of the stay 53 
and to the journal axis of the portion 54 on the housing. Alternatively, 
in this variation the end 52 is connected to portion 54 by an elastically 
deformable device 56 (FIG. 9) by pivoting about an axis parallel to the 
direction of the axis 55 (FIG. 8) which has just been described. All of 
these devices having the object of dampening the stress peaks to which the 
end 52 of the stays, pinched between the ground and the tire tread, is 
subjected. 
In another variation of the invention, the ends 57 and 60 (FIG. 10) of the 
corresponding wall chains 58 and 59 are fixed to a rigid stirrup 61. In 
turn, rigid stirrup 61 is fixed at a single point 62 of the corresponding 
stay 63 located in the middle of the tire tread, when the snow chain is in 
place. 
In another version of the invention, the grip of the inner wall chain 65 is 
sought to be improved. In this version, the crosspieces 67 are lengthened 
sufficiently so that the inner wall chain 65 assumes a substantially 
elliptical form, the major axis of which is parallel to the bisecting 
plane of the angle 68 formed by the stays 64 when it is in place. 
As specified at the beginning of the description, all the other devices for 
insertion between the tire treads that are compatible with the use of the 
wall chains fall within the scope of the invention. 
When the diameter of the wheels and/or the width of the tires change within 
reasonable margins, the adjustment of the dimensions occurs naturally 
through a variation of the angle 37 (FIG. 1) of the stays 32 and of the 
angle 40 of the maintaining arms 12 and 13. The same tensioning assembly 
can be mounted with different lengths for the wall chains. 
The present device, including all of its variations, is also suitable for 
surfaces, particularly driving surfaces other than snow, such as mud, 
sand, and vegetation-covered grounds.