The most widely sold types of snow chains comprise a ring- shaped means passing on the inner side of the wheel, ano- ^■ ther ring-shaped means on the outside and a series of trans¬ versal elements that unite the two said means forming a single whole which is then secured to the wheel; practically speak¬ ing the structure is held to the tire only, there becoming stabilized by the friction and tension created. Putting on said chains is nearly always a difficult opera¬ tion partly because the ordinary driver is not a mechanic and partly because chains have to be mounted when out in the road often under adverse climatic conditions. The number of transversal chains cannot generally be varied and may therefore be too many in some situations and too few in others. Some types of chains are easier to mount, give a better performance and are adjustable, but these are . very expensive and are not suitable for universal applica¬ ion. The above invention eliminates these drawbacks at the same time offering important advantages as will be explained be¬ low.

Subject of the invention is a device for application to the wheels of motor vehicles under snowy conditions and com- prises one or more separate chains for mounting transver- sally by means of gripping contrivances one at each end of each chain.

The device comprises a fastening means consisting of two elements associated together by an ar iculation, one ele- ment having a hook and the other a lever, this second ele ^¬ ment therefore functioning as a lever.

One end of the chain is attached to said lever element at a short distance from the above articulation. In one type of execution a second hook is placed at the other end of the chain. Said second hook and the one fixed to the hooking element of the fastening means are both made so as to fit tightly onto the edges of the rim on each side of the wheel on which the tire is mounted. Therefore, according to whether the lever element is opened back and aligned with the hooking element during mounting, or else superimposed over said hooking element during use, there will be a maximum, or a minimum, distance between the two hooks, namely between the hook mounted at one end of the chain and the hook fixed to the hooking element of the fastening means.

Said maximum distance makes possible easy application of the device to the rim of the wheel.

The minimum distance ensures the necessary tension on the chain to keep said chain stable on the wheel. The device comprises one or more elastic parts whose pur¬ pose is to facilitate application of the chain device while ensuring that sufficient tension is maintained. Said elastic parts preferably take the form of a traction spring. The lever element, forming part of the fastening means, can be locked in its functioning position by means of a lock¬ ing ring with snap closure that can hook into the hole in a lug fixed to the hook element of the fastening means, said lug emerging through a hole in the lever element. Said locking rings of the fastening means, on all the chains mounted on the wheel, are connected by an annular elastic

cord to keep them in position when the vehicle is moving. In one execution the lever element of the fastening means can be automatically locked in the functioning position by a flat spring associated to the hook element, said flat spring having at one end a tooth-like projection. When the lever element is pressed down onto the hook element, said tooth passes through a hole in said lever element and fits tightly onto the edge of said hole. In one type of execution the hook element of the fastening means comprises two tongues, perpendicular to said element, facing towards the hook and situated close to it so that, when the chain device is mounted on the wheel, said tongues press against the side of the tire and contribute to hold¬ ing said chain device stable. In one type of execution there is, at one end of the chain, a semi-rigid tie means ending in a loop while, at the other end of said chain, there is a fastening device terminating in a hook shaped to accept said loop. Application of the device to the wheel is therefore made by fitting said loop into the hook on the fastening means while it is still open, the above rod having first been passed through one of the holes in the rim; it is then suf¬ ficient to snap the fastening means shut in order to keep the whole device securely fixed to the tire. Characteristics and purposes of the invention will be made still clearer by the following examples of its execution illustrated by diagrammatic drawings.

Fig.1. Perspective view of the chain device, open. Fig.2. Perspective view of the wheel of a motor vehicle with the chain device mounted on it.

Fig.3. Perspective view of the fastening means of the chain device with spring catch lock.

Fig. . The fastening means in Fig. 3 when closed. Fig.5. Perspective view of the wheel of a vehicle with chain device comprising a fastening means with projection for applying pressure on the tire. Fig.6. Perspective view of the chain device to pass through the rim. Fig.7. Wheel o ^" f vehicle with the chain device of Fig. 6, in perspective. On the wheel ( 10) with rim (11) and tire (12) there are four separate chain devices ( 15) each comprising a main hook (17) at one end of the chain ( 16) and a closed fas¬ tening means (18) at the other end.

Traction spring (19) is situated between said hook and the chain, said spring having hook eyelets at each end, one to fit into the hole (20) in the main hook and the other to fit into the first link of the chain.

The fastening means comprise an element 21 at one end of which there is a hook (22), subs antially similar to the main hook (17), and having at the other end two lugs (32) supporting a pin (23) on which the lever element (25) arti¬ culates by means of its side pieces (24).

At a certain distance from this articulation, said lever element (25) has holes (26) through which the triangular link (27) passes, said link being connected to the last nor- mal link of the chain while, at its free end, said lever element has a tongue-shaped closing means (28). Close to the free end of the lever element (25) there is a cleft (29) into which the projection (30), forming part of hook element (21), can penetrate. In said projection there is a hole (31) and, when the fas¬ tening means is closed, as in Fig. 2, said hole is external

to the lever element.

Each chain device is mounted on the wheel separately from the others .

To mount a chain device the hook ( 17) grips the edge (35) of one side of the rim ( 11) while hook (22), forming part of the fastening means ( 18) kept in its open position, fits tightly on the edge (36) of the other side of said rim.

Having done the above the fastening means is then closed by snapping the lever element (25) into the hook element(21) this being sufficient to tighten the chain and keep it sta¬ ble round the tire.

The tension so achieved is created by the spring ( 19) which is pulled out when the triangular link (27), fixed to the chain ( 16), approaches the hook (22) as the lever element (25), forming part of the fastening means ( 18), closes onto the hook element (21).

The effort needed to press on the above tongue (28) of the lever element (25) and stretch the spring ( 19) is greatly lessened due to the effect of the levering arm created by the distance between said tongue (28) and the holes (26) through which the triangular link passes.

To give stability to the fastening means when closed, elas¬ tic metal hooking means (40), joined together by an elastic cord (41), are inserted into the holes (31) in the projec- tions (30) emerging from the fastening means ( 18).

Figures 3 and 4 illustrate another execution of the fasten¬ er indicated by the number (42). A spring catch (44) is mounted on hooking element (43) of said fastener (42) by means of the pin (45). Said spring catch is bent to form a tooth (46) and an in ^¬ clined plane (47) and is placed so as to snap into the

square hole (48) made in the lever element (49). Therefore, when the above fastener is closed (Fig.4), said tooth (46) presses hard against the edge (52) of the hole. (48) locking the lever element (49) and stabilizing the chain (50) round the tire.

To release the fastener it is sufficient to press back the inclined plane (47) as shown by the arrow (51) in Fig.4.

Fig. 5 shows an execution of the fastener in which, com¬ pared with the one illustrated in Fig. 3, the projections (60) and (61) extend outward, from the body of element (56) of fastener (55), perpendicularly to the plane of said fast¬ ener and lie in the same direction as the hook (57). As may be clearly seen in said Figure 5, when the fastener (55) is fitted onto the rim (58) of wheel (54), the tips of said projections press against the side of the tire (59) and hold it due to tension on the chain (62) setup by thetrac- tion spring (63)-

Simultaneous holding action is thus obtained by the hook (57) on the edge (64) of the rim and by the projections (60-61) on the tire.

Figs. 6 and 7 illustrate a variant provided by the presence of the braided metal tie (70) which, when mounted, passes through one of the holes (80) that generally exist in rims (81) with tires (82). This execution comprises a chain (71, one spring (72), a second spring (73) and a fastening means (74). Said fastening means has a hook (75) placed to catch onto the loop (76) of the braided metal tie (70). On closing the fastening means as in Fig.7, the front end (78) of the tongue-shaped means (77) comes up against the hook (75) thereby closing it so that loop (76) of tie (70)

cannot escape from said hook. Advantages

The separate chain devices applicable directly onto the rim ensure a quick and easy chain-mounting operation that offers a high degree of security.

Application to the wheels can be made without raising them and without long and complicated maneuvering. When not required this device is so compact and light that it takes up very little space when stored in the vehicle. One or more chain devices can be mounted on the wheel as dictated by road conditions.

The cost of each chain device is very moderate, outlay for a set being far less than what is usually spent on conven¬ tional snow chains.