In the Swedish patent 8801746-2 is shown an antiskid device comprising
a starshaped rubber structureor rotor provided with pieces of chain in the outer
ends of the arms of the star. When used the star is rotated by the vehicle wheel
successively placing the pieces of chain below the vehicle wheel. This device
has proved to work very well and provides in a comfortable and soft way an increase
Since at this type of antiskid device no separate pulley is in contact
with the vehicle wheel to provide the rotation of the star, this must instead be
provided by the rubber arms themselves. This means that in order to throw the chains
sufficiently in under the vehicle wheel the outer ends of the arms must be brought
in contact with the vehicle wheel inserted between the wheel and the ground since
the chains themselves are unable to transfer the necessary rotational force to
the star. This has resulted in a great wear giving an unacceptable short useful
life for the rubber structure. The wear on the rubber arms in the ends where the
chains are fastened will be so great that the chains already after a short time
are torn away.
This problem has been found so great and so difficult to solve that
the solution despite its other advantages has been rejected entirely by the technicians
in the field.
The invention has as its object to make the use of an antiskid device
of this kind possible by providing a wear resistant connection between the rubber
arms and the short chain pieces giving a long useful life for the device.
This object is in accordance with the invention in a first embodiment
solved by the providing the innermost fastening chain link for each piece of chain
with a protrusion of some kind that holds the radially inner end of the fastening
link up from the ground. In this way the outer end of the rubber arm is also held
up from the ground and instead the protrusion transfer the vertical forces transferred
from the vehicle wheel to the outer ends of the rubber arms via the fastening link
to the ground. Since the end of the arm is free from contact with the ground no
abrasion against the ground occurs and the useful life is instead dictated by
the chains, which can be hardened and thus may last a very long time. Still however
the necessary tangential force or torque rotating the rubber structure is transferred
to the rubber structure.
Alternatively the object of the invention to achieve a wear resistant
connection between the chains and a supporting structure of in particular rubber
can instead be obtained by the innermost fastening link that may be vulcanized
to the rubber structure being angled so that when this link by the vehicle wheel
is being pressed against the ground the inner end is lifted from the ground, the
link acting as a lever. also in this embodiment the rubber structure is lifted
up from contact with the ground and kept out of the force transfer from the vehicle
wheel to the ground and practically no wear will occur on the rubber structure.
Of course both of the above alternatives may be used simultaneously
Since the chain carrying supporting structure will not wear one can
also consider the possibility of making the chain pieces exchangeable while the
supporting structure is reused.
The invention can be embodied in many ways and below two embodiments
are described as nonlimiting examples with reference to the drawings.
Fig. 1 shows in view from behind an antiskid device according to the invention,
fig 2 a view from above of the same antiskid device and fig 3 is a detail seen
in a side view and a horizontal view.
In the embodiment shown in fig 1 and 2 an arm 15 only a part of which
is shown and that can be constructed and arranged according to the known art for
devices of this kind holds or supports an anti skid rotational device or rotor
with upper radial arms 11 and lower radial arms 12. The arms 12 are via lateral
connections 13 connected to the outer 1 ends of the arms 11 and 12. This provides
a framework construction that despite a good ability to support the chain pieces
3 and to maintain the structure flat, allows the great deformation that is necessary
when the cain pieces successively are held under the vehicle wheel, as is clearly
shown in fig 1 and 2. Between the upper and lower arms 11 an 12 respectively is
located a ring 14, that efficiently contributes to holding the rotatable starlike
device or rotor flat, without obstructing its flexibility. Possibly one can also
consider this ring as an integer part of the star, that may be molded in one piece
with this. The starlike framework structure can also be constituted by separate
arm means or modules that are glued or connected in some other way.
In the outer ends 1 of the rubber arms or the tips of the star a
fastening chain link 2 of a short piece 3 of chain is vulcanized into the rubber.
The fastening chain link 2 is provided with Projections or heels
4, 5, extending from the fastening chain link downwards towards the ground below
the outer tip 1 of the arm and through this. When the invented device is used the
protrusion will hold up the outer end of the rubber arm preventing its contact
with the ground.
As can be seen the fastening link is also angled so that when its
outer end is pressed against the ground by the vehicle wheel rolling over it, it
will function as a lever lifting the inner end upwards pivoting around the tip
of the angle. In this way also the outer ends of the arms ar lifted upwards preventing
their contact with the ground and thus also the wear thereof in an efficient manner.
I addition to the protrusions or heels in the inner end of the fastening
link that is vulcanized into tips or points 1 of the rubber arm the fastening link
can also be provided with area increasing elements in order to increase the grip
between the vulcanized metal and the rubber.
In the shown fastening of the chain pieces 3 to the outer ends 1
of the arms these and the connection between these is held up from the ground in
two supplementary ways. First the angle tip 6 and the heels 4 and 5 serve as a
bridge preventing the rubber for coming in contact with ground. This when the force
from the vehicle wheel lies inward radially in relation to the angle of the fastening
Secondly the fastening link serves as a two-armed lever lifting the
inner end of the fastening link and the outer end of the rubber arms upwards when
the force from the vehicle wheel lies radially outward of the angle.
Due to these two the fastening or joining, of the supporting structure
and chain pieces, protecting mechanisms the fastening will be protected within
a comparatively large radial range corresponding to slightly more than the length
of the fastening link 2. This also reduces the demand of exactness in the mounting
and controlling of the anti skid device, which in particular can be of importance
for wheels that steer, since the wheels on steering at many modern cars carry out
lateral motions in relation to the body of the car.
Within the frame of the invention one can of course consider the
use of only one of the above embodiments or principles to protect the fastening
of the chain pieces in the supporting structure. For example it is conceivable
to make the fastening link shorter and without the angel so that the support against
the ground is achieved by means of the heels and the next chain link that grips
around and below the fastening link.
Practical experiments have shown that with the described fastening
the fastening link after 100 km of continuous drive on asphalt covering will only
be worn slightly more than the remaining links in the chain pieces. The rubber
around the fastening however was totally unaffected and unworn. This also on the
upper side that is in contact with the vehicle wheel against which thus no separate
contact element is needed. Presumably no movement at all take place between the
vehicle wheel and the outer end of the rubber arms, and the only movements that
may possibly occur take place between the chain links and the ground. Preferably
all the chain links including the fastening links are made of a material with good
wear resistance qualities as for instance hardened steel.
As is apparent from fig 2 the innermost chain link (fastening link)
will become locked between the vehicle wheel and the ground in the position corresponding
to the position obtained when the piece of chain is thrown in under the vehicle
wheel and is stopped by this. The piece of chain including the fastening link
will due to this locking then have small possibilities to turn until once again
freed by the vehicle wheel behind this. This turning or pivoting may instead take
place when the chain links are becoming free. This possible movement may give rise
to some wear on the fastening link where it is in contact with the ground, but
since this is of metal the wear will be small. It is also possible to increase
the amount of metal at the tip of the angle, for instance by welding to compensate
for this abrasion. In order to facilitate the turning of the link the apex of the
angel can be made pointshaped.
In a further development of the inventive thought the fastening link
may instead of being vulcanized to the supporting (rubber) structure include snap
or other gripping means in order to allow detachable fastening of the pieces of
chain, In this way it would be simple to exchange the short pieces of chains that
after the improvements of the invention are the parts that become worn first.
in this way it would be possible to improve the economic of the invention further.
For instance the fastening links may include a horizontal elongate
opening into which the outer ends of the arms are inserted and were the fixing
can be achieved by means of a bolt inserted vertically through fastening link as
well as outer arm ends. As an alternative the fastening link can be dimensioned
so sturdy that it survives a number of chain pieces that in turn can be fastened
with some kind of snap hook means in the fastening link.