The present invention relates to a wheelset freely installed onto basic track gauges of the railway administrations in the world.

2.Background of the Invention

A wheelset is known for different types of track gauges consisting of independently rotating running wheels mounted by means of bearings to inserted and freely sliding along the axle muffs which external edges are placed in the axle-boxes.

Transverse grooves are formed on the muffs. Transverse prisms are provided on the top sides of the axle-boxes where the position of said boxes is determined by a remote fixer. There is another embodiment where for a plurality of track gauges the external prism is not provided and is replaced by a remote fixing element inserted in a transverse slot formed in the axle and said fixing element is projected laterally out of the axle-box in π-shape. The connection between the wheelset and the frame is performed by a strap secured to the face of the axle by means of bolts and a journal welded to the frame and entering an opening formed in the strap. There are provided plates for covering the grooves of the muffs when using the wheelset for narrow track gauges. This type of wheelset has some disadvantages which confine its usage only to some large heavy trucks accompanied by stuff obliged to stop the train if a signal for overheating of bearing of the wheelset is received. Besides, it must be equipped only with solid axles as in their ends too deep slots are formed where said remote fixing element is inserted. The presence of solid axles makes the construction heavier and there is no possibility for constructive build-in of the devices detecting overheated bearings which makes the

use of these wheelsets inadmissible. When using the wheelset for a plurality of track gauges the fixing of the wheel in a specified track gauge is performed only by part of the vertical loading transmitted through a tooth entering a channel. Thus the necessary locking reserve is not achieved, especially in case of lighter (empty) tracks under great transverse forces applied from the wheel and the muff to the axle-box and further by the remote fixer to the axle-box and again to the opposite axle-box and the spring hanging. Since the application points of these forces are at different levels, the moments generated decrease, even nullify the value of the loading transmitted from the tooth to the channel which results in a split between them, i.e. the engagement of the wheel can be cut off and the following consequences can happen. Besides because of the constant presence of a vertical loading (typical for railway trucks) transmitted from the axle-box to the muffs, respectively to the axle, the split between determined tooth and channel is always performed by rotating round the other tooth and channel, if provided. If not, the rotating is round the support of the axle-box in the axle.

As it was noted above, in this kind of wheelset only a part of the vertical loading is transferred from the axle-box to the muff, which leads to transmission of lower forces between the muff and the axle, i.e. slighter engagement is created between them. This results in slipping under the axial forces and the following undesirable wearing out and scrapping.

As for the remote fixing element set against the slot in the axle, the vertical loading transmitted by it is even smaller, i.e. so is the engagement with the axle.

On the other hand, the butt joint of the axle and the frame by strap is not conventional and thus the possibility

for replacement of this wheelset with standard conventional wheelset for one track gauge is eliminated - obligatory condition for admitting freely installed wheelsets for use. 3.Summary of the Invention The above described disadvantages of the known solutions are avoided entirely or their influence is reduced to acceptable level in an inventive wheelset for the basic track gauges in the world, consisting of independently rotating running wheels mounted by means of bearings to fixed and freely sliding along the axle muffs where the external edges of the wheels are placed in the axle-boxes. Transverse grooves are formed on the muffs. Teeth are provided on the top side of the axle boxes. In the normal and broad track gauges two teeth from the axle-box, disposed asymmetrically in relation with its longitudinal axis, are engaged to the channels in the muffs. In the narrow track gauges with lighter loadings the engagement is realized only by the tooth disposed between the middle of the axle-box and the wheel. In order to match the wheelset to the overall sizes, i.e. to reduce the length of the axle and the muff, respectively the length that protrudes laterally from the track, the distance between the two teeth of the axle-box is equal to the movement of the wheel when the wheelset passes from the normal to the widest one from the narrow wheelsets. A cross joint is fixed by bolts to the face of the axle and consists of a bar, disposed in a longitudinal direction before the face of the axle. The ends of the bar enter oveably into slots formed in bilaterally disposed protrusions of the axle-box, thus the relative transverse movability between them is avoided. The slots in the protrusions of the axle-box are disposed with an insignificant looseness above these ends. From the center of the cross joint a vertical part is erected connected by means

of bolts to remote element determining the maximal permissible movement down of the wheelset in relation to the muffs as well as the limiters of the frame of the bogie.

In the narrow track gauges only the tooth disposed between the middle of the axle-box and the wheel is engaged to the muff. The other tooth remains free and the loading which is supposed to be transmitted to the muff and then to the axle is actually transmitted to the axle by means of the bilaterally disposed protrusions on the axle-box in the zone where these protrusions for the wide track gauges are disposed with an insignificant looseness over the bilaterally disposed protrusions of the cross joint. In this case this looseness is eliminated and the respective part of the vertical loading is transmitted on this point of contact of the protrusions on the cross joint.

There is a solution for direct transmission of the loading from the external prism (tooth) to the axle where at a distance from the face of the axle a feather is secured to the axle from its top side beside the zone of the internal tooth. The upper surface of the feather passes with an insigni icant looseness under the lower surface of the teeth. Then in the ^" narrow track gauges when the muff is pulled internally from the middle of the axle-box, its external tooth contacts the feather preventing turning between the axle and the muff. Thus the conventional means for supporting the vertical position of the butt joint of the wheelset and the frame become unnecessary as well as the other mo ifica ions following the presence of the feather.

Direct transmission of the loading on the axle is possible if the bilaterally disposed protrusions from the axle-box are connected with each other by curved strap located between the cross joint and* the face of the muff and extended with an insignificant looseness under the very end of the axle.

For a more reliable locking of the wheels in the basic narrow track gauges two lower teeth are provided disposed symmetrically in the vertical plane of the internal tooth and placed in the opposite sides of the lower part of the side 5 walls under the axle-box, the teeth having in their upper part guide surfaces engaging laterally the muffs. The lower part of the teeth enters channels formed in wings laterally protruding from the lower part of the muffs. These wings may be provided only for the narrow track gauges and if 10 necessary- for other types.

A limiting step is provided in the axle as a restriction against shifting of the wheel in the most narrow track gauge where the muffs touch the step. This way of locking is more acceptable than providing lower teeth in case 15 the wheelset is supposed to be used only for one narrow track gauge. This is a one-side restriction but it ignores entirely the possibility of separating of the tooth to the top side of the axle-box.

The advantages of the present invention in relation to 20 the known solutions are the following:

-shifting between teeth and channels in movement for normal and broad track gauges are avoided;

-a way of disposing the teeth is introduced providing minimal length of the wheelset;

25 -three solutions are proposed for assuring the locking for narrow and eventually for broader track gauges and one solution for the most narrow track gauges only which can be i applied selectively when using the invention for a limited number of track gauges; ^* 30 -there is a possibility for using light hollow

(tubular) axles when freely installed wheelsets for narrow track gauges is applied;

-constructive premises are provided for building-in of devices for detecting of overheated bearings;

-simple and easy solution is realized for guiding the muff in the axle-box by introducing lower teeth with combined action as well as a simple solution for avoiding the turning of the muffs around the axle; -the wheelset can be used for conventional bogie frames without their modifications.

4.Description of the Drawings

Preferred embodiments of the present invention are shown on the accompanying drawings, where: Fig.1 is partial transverse cross-section of the wheelset in the position of the broadest track gauge;

Fig.2 is partial Transverse cross-section of the wheelset in the position of the most narrow track gauge;

Fig.3 is partial side view of a bogie equipped with said wheelset and partial cross-sections through the axle-box protrusions perpendicular to the axle and the teeth; and

Fig.4 is partial transverse cross-section through the middle of the axle-box in position of the broader narrow track gauge when using curved strap. 5.Description of the Preferred Embodiment of the

Invention

The wheelset 1 consists of independently rotating running wheels 2 mounted by means of bearings to freely sliding along the axle 3 muffs 4 where the external edges of the wheels 2 are placed in the axle-boxes 5. Transverse grooves 6 are formed on the muffs 4. Teeth 8 and 11 are provided on the top side 7 of the axle boxes 5. In the normal and broad track gauges two teeth 8 and 11 of the axle-box 9 are placed asymmetrically in relation to the middle 10 of the axle-box 9, where the teeth are engaged to the channels 6 of the muffs 4. In the narrow track gauges the engagement is accomplished by tooth 11 located between the middle 10 of the axle-box 9 and the wheel 2 and the distance m between the

teeth 8 and 11 of the axle-box 9 is equal to the movement n of the wheel 2 and the muff 4 when the wheelset 1 passes from the normal to the widest narrow track gauge.

A cross joint 13 consisting of longitudinally disposed 5 before the face of the axle 3 bar 14 is fixed by bolts 12 to the face of the axle 3. The ends 15 of the bar 14 enter moveably into slots 16 formed in bilaterally disposed protrusions 17 from the axle-box 9. These slots 16 in the protrusions 17 from the axle-box 9 are formed with

10 insignificant looseness .A. over the ends 15. The cross joint 13 has a vertical part 18 connected by bolts 19 to a remote element 20 defining the maximal admissible movement down 3 of the wheels 2, the axle 3 and the muffs 4 in relation to the axle-boxes 9 and their movement V2 in relation to the

15 limiters 21 of the frame 22 of the bogie.

In a further embodiment a feather 24 is fixed to the upper end of the axle 3 at a distance from the face of the axle 3 beside the zone of the internal tooth 11. The upper surface of the feather 24 is located with an insignificant

20 looseness δ under the lower surface of the external tooth 8, so that in case of narrow track gauges when the muff 4 pulls in from the middle 10 of the axle-box 9 after insignificant turning of the axle-box 9 around the internal tooth 11, the tooth 8 contacts the feather 24 extending in such a manner as

25 to prevent the relative turning between the muff 4 and the axle 3.

In a further embodiment there is no contact between the ♦ tooth 8 and the feather 24 but a curved strap 36 envelopes from above with an insignificant looseness the very end of ^' 30 the axle 3 which is fastened (welded) in its both ends to the upper surface of the protrusions 17 of the axle-box 9. In the narrow track gauges the external tooth 8 is not engaged and the curved strap 36 contacts the axle 3, in this way

transmitting a proper part of the vertical load. On the other hand the necessary fixing (guiding) of the axle 3 to the axle-box 9 is carried out by means of the curved strap 36. In this embodiment there is no need for parts of the protrusions 17 of the axle-box 9 to extend over the ends 15 of the perpendicular bar 14 of the cross joint 13.

In the basic narrow track gauges the locking of the wheels 2 is realized not only by means of the internally located tooth 11 but also with two teeth 25 disposed in the vertical symmetrical plane of the tooth 11. The teeth 25 are oppositely disposed in the lower part of the side walls 23 of the box 5 of the axle-box 9 and enter slots 26 formed in wings 27 laterally protruding from the lower part of the muffs 4. In their upper end the teeth 25 are provided with guiding surfaces 28 leading and engaging the muffs 4 and fixing them against turning.

A step 29 is provided on the axle 3 restricting the movement of the muff 4 towards the middle of the axle 3.

The space 31 in the ends of the cavity 30 of the axle 3 confined by the caps 32 and 33, is filled with heat- conductive liquid 34. In case of heating of the bearing 35 the liquid 34 transmits the heat to the face of the axle 3 and thus creates conditions for detecting of overheated bearings 35 by devices mounted on the railway road. 6.Application of the Invention

The present invention can be used by applying all or some of the above cited embodiments taking into account the specific conditions for its manufacturing and maintaining.

Besides for all basic track gauges in the world, the present invention can be applied also for maintaining a smaller number of track gauges. In this case only .the respective necessary alternative solutions can be applied.