GB2038992A

GB2038992A - A gear

Info

Publication number: GB2038992A
Application number: GB7941229A
Authority: GB
Original assignee: RO KA TEKNIK APS
Current assignee: RO KA TEKNIK APS
Priority date: 1978-11-30
Filing date: 1979-11-29
Publication date: 1980-07-30
Also published as: IT7927724A0; DE2947088A1; DK541978A; IT1126435B; SE7909386L; DE2947088C2

Abstract

A gear comprises a driving input shaft (2), an output shaft (3) coaxially situated relative thereto, and a housing (4) with an inner running surface (5) extending coaxially with the two shafts. The input shaft (2) comprises an eccentrically arranged annular driving member (6), which may rotate freely relative to the input shaft (2) and which is adapted to press an unstretchable, flexible, and endless drawing means (7) against the inner running surface (5). The output shaft comprises a coaxially arranged output wheel (10) fixedly secured to the output shaft and adapted to mesh with the drawing means (7) along an axial surface in such a manner that said drawing means is tightly arranged both about the driving member (6) and the output wheel (10). <IMAGE>

Description

SPECIFICATION A gear The invention relates to a gear comprising a driving input shaft, an output shaft coaxially situated relative thereto, and a housing with an inner running surface extending coaxially with the two shafts.

Previously known gears of the above type such as planet gears are relatively comp!icated and therefore expensive to manufacture.

The gear according to the invention is characterised in that the input shaft comprises at least one annular driving member eccentrically arranged within the housing, which may rotate freely relative to the input shaft, and which is adapted to press an unstretchable, flexible, and endless drawing means against the inner running surface of the housing, and that the output shaft comprises at least one output wheel coaxially arranged within the housing and fixedly secured to the output shaft and furthermore adapted to mesh with the drawing means along an axial outer surface in such a manner that said drawing means is tightly arranged both about the annular eccentrically arranged driving member as well as about the output wheel, the drawing means, the surfaces thereof abutting the driving member, the inner running surface of the housing, and the output wheel being adapted in such a manner that substantially all types of mutual sliding movements are avoided at normal load.

As a result a gear with a relatively high efficiency is obtained, which is relatively inexpensive to manufacture and which furthermore is compact. When assembled, the gear and motor unit has proved to be very suitable in connection with an electric wheel chair, whereby the unit is integrated in the wheels of the chair since the gear may be shaped as hubs. As the gear is compact, it does not take up much room nor weigh much, and for which reason it may be used in connection with a wheel having an appropriately small diameter. Furthermore, the gear is relatively inexpensive-to manufacture as it is relatively simply constructed of easily produceable parts.

The endless drawing means may according to the invention be formed as a belt or a chain.

Furthermore according to the invention, the input shaft may be provided with an annular supporting body rotatably and coaxially arranged within the housing and having the same diameter as the output wheel, and which is adapted to supportingly mesh with a portion of the endless drawing means on the side of the eccentrically arranged driving member opposite the output wheel along a peripheral surface. In this manner an efficient support of the drawing means during the rotation of the shafts is obtained.

Moreover according to the invention, the driving member and the output wheel or when the supporting body is used, the output wheel and the supporting body may comprise substantially radially projecting flange portions for preventing axial displacement of the drawing means.

According to the invention the output shaft and the output wheel may be integrally shaped in the form of a sleeve-shaped output shaft forming the bearing housing for the input shaft, whereby a particularly compact gear is provided, and whereby the output shaft and the input shaft may optionally extend to the same side of the gear.

Furthermore according to the invention, the sleeve-shaped output shaft may be secured to a motor housing and the input shaft may be coupled to the motor shaft. As a result a rotation of the housing instead of the output shaft is provided, whereby the gear is particularly suitable for use as a hub.

The gear may according to the invention also comprise several eccentrically arranged driving members with their respective drawing means of an individual length and eccentricity, the running surface may be shaped on rotatable rings adapted to co-operate with their respective drawing means and ta selectively lock against rotation b.y means of locking devices activatable from the outside, and the drawing means of one driving member may co-operate with the sleeve-shaped output wheel integrally shaped with the supporting body at the first drawing means. In this manner a gear is provided, which possesses the possibility of two gear ratios depending on which rotatable ring is being locked.

According to the invention, the housing may be provided with radial, transverse apertures in the portions) forming the running surfaces, thus ensuring a fine cooling of the running surface at the same time as the mouths of the apertures increase the friction between the running surfaces and the drawing means.

Furthermore according to the invention, the drawing means may be a belt with an inserted ribbon-shaped reinforcement provided with apertures, thus providing a belt being particularly advantageous as the ribbon-shaped reinforcement increases the unstretchability of the belt. The apertures ensure the connection between the portions of the belt being on their respective sides of the reinforcement.

According to the invention it is particularly preferred that the drawing means may also be a belt with a circumferential wire reinforcement and a transverse steel needle reinforcement.

The drawing means may according to the invention comprise transverse recesses increasing the friction, thus providing a particularly fine efficiency of the gear.

According to the invention the drawing means may also be provided with transverse teeth on the radially inner and/or outer side, whereby the desired friction and efficiency of the gear is particularly high.

Moreover according to the invention, the side turning radially inwards of the drawing means may comprise a circumferential continuous recess or a circumferential projection adapted to co-operate with the driving member. As a result the displacement of the drawing means in axial direction is additionally prevented.

The drawing means may according to the invention comprise one or several circumferential recesses on the outer side so as to ensure an efficient cooling of the drawing means. It is according to the invention particularly preferred that the running surface of the housing, the peripheral surface of the driving member and/or the peripheral surfaces of the output wheel and of the supporting body comprise teeth for meshing with the transverse recesses or teeth on the drawing means.

According to the invention the drawing means may furthermore comprise several, preferably identical, circumferential portions co-operating with the output wheel, the driving member, and the supporting body, respectively, so as to ensure an efficient cooling of the drawing means. More' over the running surface of the housing may be adapted in such a manner that it only meshes with the drawing means along the portions of the drawing means also meshing with the supporting body and the output wheel in order to increase the cooling effect.

The various portions of the drawing means may according to the invention be mutually connected by means of transverse, through shafts, thus providing a particularly fine stability of the belt.

It is according to the invention particularly preferred that also the number of teeth on the running surface is higher, preferably one more, than the number of teeth on the side of the drawing means co-operating therewith, and that the number of teeth on the output wheel and the supporting body is lower, preferably one less, than the number of teeth on the side of the drawing means co-operating therewith.

Finally according to the invention, the drawing means may be a chain of chain fish joints coherent both lengthwise and crosswise the drawing means, whereby both a particularly good cooling and a particularly high efficiency are obtained.

The invention will be described below with reference to the accompanying drawing, in which Fig. 1 is a radial, sectional view through a preferred embodiment of a gear according to the invention, said sectional view being taken along the line I-I of Fig. 2, Fig. 2 is a sectional view taken along the line Il-Il of Fig. 1, Fig. 3 is a sectional, diagrammatical view through a second embodiment of a gear according to the invention, Fig. 4 is a sectional view corresponding to the views of Figs. 2 and 3 of a third embodiment of the gear according to the invention, but whereby the output shaft is secured to a motor housing, Fig. 5 is an axial, sectional view through a fourth embodiment of the gear according to the invention, whereby the gear has the possibility of two gear ratios, Fig. 6 is an axial, sectional view through a part ofa gear according to the invention, whereby a ring is illustrated which forms a running surface and comprises transverse apertures, Fig. 7 is a perspective view of a drawing means, whereby a portion of the reinforcement for the sake of clarity is uncovered, Fig. 8 illustrates a portion of a second embodiment of the drawing means, which for the sake of clarity has been partly cut, Figs. 9 to 11 illustrate various embodiments of the drawing means, whereby Figs. 9 and 11 are sectional views and Fig. 10 is a fractional view, Figs. 12 and 13 are axial, sectional views through parts of the gear according to the invention, whereby various embodiments of drawing means co-operating with correspondingly shaped adjacent parts of the gear are illustrated, Fig. 14 is a radial, diagrammatic view of a part of a gear according to the invention, which is adapted for use in connection with a drawing means in the form of a chain of fish joints, whereby for the sake of clarity portions are removed and the construction lines used when preparing the Figure are maintained, Figs. 1 5a toj illustrate embodiments of fish joints forming part of a chain of fish joints, Fig. 16 is an axial, sectional view through a part of a gear according to the invention, whereby the use of a chain of fish joints in a predetermined embodiment is illustrated, portions being removed for the sake of clarity, Fig. 17 is a perspective view of an embodiment of a joint forming part of a chain-shaped drawing means, and Fig. 18 is a sectional view of an additional embodiment of the gear according to the invention, whereby the inner running surface is located on a stator wheel in coaxial relation with the input shaft and the output shaft.

Figs. 1 and 2 illustrate an embodiment of the gear according to the invention, whereby the gear is generally designated 1 and comprises a driving input shaft 2 extending into a housing 4. In the housing the input shaft 2 comprises at the end an eccentrically located annular driving member 6 mounted by means of a ball bearing 9 on an eccentrical portion 8 of the input shaft in such a manner that it may rotate freely relative to the input shaft. The gear furthermore comprises an output shaft 3 coaxially mounted relative to the input shaft and comprising an output wheel 10 coaxially located within the housing. The output wheel is fixedly secured on the output shaft. The housing 4 and the output shaft 3 are mutually connected by means of a ball bearing 11.

In the embodiment illustrated, the input shaft also comprises a supporting body 12 coaxially mounted, which by means of a ball bearing 13 may rotate freely relative to the input shaft 2. The output wheel 10 and the supporting body 12 are located on their respective sides of the eccentrically mounted driving member 6, and both comprise a peripheral axial surface 14 and 16, respectively, of the same diameter The driving member 6 furthermore comprises a peripheral axial surface 1 5. The driving member 6 is dimensioned in such a manner that its radially outermost point during rotation of the driving wheel is always radially outside the peripheral surfaces 14 and 16, respectively, of the output wheel 10 and the supporting body 12.An unstretchable, flexible and endless drawing means 7 is tightly arranged about the driving member 6, the output wheel 10, and the supporting body 12.

This drawing means abuts a portion of the peripheral surface 1 5 of the driving member 5 and a portion of the peripheral surface 7 of the output wheel 10, and a portion of the peripheral surface 16 of the supporting body 12, respectively.

Radially outside the always radially outermost point on the driving member 6, cf. Figs. 1 and 2, the drawing means 7 abuts a running surface 5 shaped inside the housing 4, said running surface 5 extending coaxially relative to the two shafts.

The drawing means, the housing, the driving member, the output wheel, and the supporting body are dimensioned and adapted in such a manner that the drawing means during rotation of the input shaft contacts the adjacent parts without a sliding movement, whereby the drawing means when the housing is fixed and during rotation of the input shaft abuts the running surface 5 in the same direction as the direction of rotation of the input shaft with a thereby resulting relative rotation of the drawing means in opposite direction relative to the housing and thereby rotation of the output wheel and the output shaft in the same direction.

The supporting body is driven about together with the output shaft and ensures a uniform distribution of the load of the drawing means across the cross section thereof.

in the ideal case, a revolution of the input shaft implies that the drawing means moves a short distance in opposite direction, said distance corresponding to the difference between the circumference of the running surface and the outer length of the drawing means. Correspondingly, the output wheel is driven in the same direction corresponding to a turn, the extension of which along its periphery is equal to the inner length of the drawing means, said length corresponding to the displacement of the drawing means.

In order to prevent axial displacement of the drawing means, the output wheel and the supporting body are provided with radially projecting flange portions 1 7 and 18, respectively.

These portions are adapted to abut their respective sides of the drawing means.

The embodiment of the gear according to the invention illustrated in Fig. 3 does not comprise a supporting body. This embodiment is identical with the embodiment of Figs. 1 and 2 apart from the fact that the input shaft comprises a relatively large eccentric 20 for carrying the eccentrically mounted driving member. This eccentric extends into an axle journal 19 being in coaxial relation with the input shaft and projecting into and cooperating with an axial bore 38 in the output wheel. The axle journal 1 9 provides an additional securing of the maintenance of the straightening of the shafts during the function of the gear.

The embodiment illustrated in Fig. 4 is identical with the embodiment illustrated in Figs. 1 and 2 apart from the fact that the eccentrically arranged driving member 6 is the outermost portion of the ball bearing 9, and the output wheel 10 and the output shaft 3 and integrally shaped as a sleeve extending aboutthe input shaft and being pivotably mounted relative to the housing 4 by means of bearings 27. The output shaft is secured to a motor housing 22, cf. the drawing, by means of a securing means such as a bolt 21, whereas the input shaft is secured to the shaft 23 of the motor. The housing is shaped as a rim for a tyre 23. At activation of the motor, the fixed sleeveshaped output shaft 3 with the associated wheel 10 implies that the pivotably mounted housing 4 rotates by driving through the eccentrical driving member 6 and the drawing means 7.

The gear may, cf. Fig. 5, be adapted in such a manner that it is possible to have several gear ratios. This is ensured by forming the gear of several parts, each part substantially corresponding to the gear illustrated in Figs. 1 and 2. For the sake of clarity, the same letter a orb is used in the Figure in connection with the components of the individual parts. The gear thus comprises an input shaft 2 provided with two eccentrically mounted driving members 6a and 6b with their respective eccentricities U, and U2, respectively. Each driving member is connected to a supporting body 1 2a and 1 2b, respectively, an output wheel 1 Oa and 1 Ob, respectively, and a drawing means 7a and 7b, respectively, as the embodiments of Figs. 1, 2, and 4.

Correspondingly, the associated drawing means 7a and 7b are adapted to co-operate with their respective running surfaces 5a and 5b, respectively, said running surfaces in the present embodiment being shaped on a pivotably mounted ring 33a and 33b, respectively. One of the rings may, as desired, be locked against rotation by means of a locking device in the form of a coupling bellow 29a and 29b, respectively. At activation these coupling bellows radially press locking blocks 30a and 30b, respectively, inwards against the individual ring. The output wheel lOb is in the left portion of the gear, cf. the Figure, integrally shaped with the output shaft 3b, which is simulataneously shaped integrally with the supporting body 1 2a in the left second portion of the gear. Correspondingly, the output shaft 3a and the output wheel 1 Oa on the right portion of the gear is shaped as a sleeve pivotably mounted on and surrounding a coaxial projection on the input shaft. As illustrated, the sleeve-shaped output shaft 3a is furthermore shaped as a hub for a wheel 31.

At activation of the coupling bellow 29b in the left portion of the gear and a decoupling of the coupling bellow 29a in the right portion of the gear, the rotation of the input shaft is transferred to the output shaft 3b of the left portion and furthermore to the supporting body 1 2a in the right portion. Through the drawing means, this supporting body transfers the rotating movement to the output wheel 1 Oa and the output shaft 3a and subsequently to the wheel 31. When decoupling the coupling bellow 29b and activating the coupling bellow 29a, the rotation of the input shaft 2 is transferred directly to the output wheel 1 Oa and the output shaft 3a and subsequently the wheel 31 through the drawing means 7a.Owing to the differences of the eccentricity and of the diameter of the peripheral surfaces on the output wheel and the supporting body, respectively, in the two portions, the gear ratio provided differs.

The rings 33a and 33b forming the running surfaces are pivotably mounted relative to the remaining portion of the housing 4 through diagrammatically illustrated bearings 34, 35, 36, and 37.

As illustrated in Fig. 6, the rings forming rotatable running surfaces, cf. Fig. 5, or the housing 4 may be provided with transverse apertures 40 for cooling the portion of the housing subjected to the influence af the drawing means 7. During rotation of the eccentric driving member 6, the surface of the drawing means acting on the running surface 5 is pressed a short distance into the transverse apertures 40. As a result elevations 41 are formed in the drawing means on the contact spot, cf. the Figure, whereby the frictional meshing of the drawing means and the housing is improved.

The drawing means may be shaped in various manners and be manufactured in many various ways. In order to ensure the unstretchability, it may for instance as illustrated in Fig. 7 be provided with a ribbon-shaped reinforcement 42 with transverse apertures 43 to ensure cohesion of the rim portions located on both sides of the reinforcement. As illustrated in Fig. 8, the drawing means may also be shaped as a chain or rim-like member with an inner cogging 45 engaging a corresponding coating on the peripheral surfaces engaging the inner side of the drawing means in the gear. Correspondingly, the outer side of the gear may be provided with recesses 44 to increase the flexibility of the drawing means.

Furthermore, the reinforcement may comprise thin wires 39 and transverse steel needles 46 increasing the transverse rigidity of the drawing means. The inner cogging 45 may extend along the entire width of the drawing means or as illustrated in Figs. 9 and 11 only across the portions of the drawing means engaging the output wheel and the supporting body, respectively, a circumferential recess 47 engaging the eccentrically mounted driving member being shaped between the coggings. In this manner an additional securing is provided against axial displacement of the drawing means, whereby the previously mentioned radially projecting flange portions 17 and 18, cf. Fig. 2, on the output wheel and the supporting body, respectively, may, if desired, be omitted.The above recesses 44 increasing the flexibility of the drawing means furthermore imply that the drawing means is provided with a resilient frictional coating, cf. Fig.

10, which is easily deformed at clamping between the eccentrical driving member and the running surface of the housing. In this manner a uniform contact pressure is ensured at the same time as compensation is provided for a certain .wearing of the frictional coating. The outer side of the drawing means may also, cf. Fig. 11, be provided with circumferential recesses 48 facilitating the cooling of the drawing means or replacing the transverse recesses 44.

As illustrated in Figs. 12 and 13, the drawing means may comprise several portions 49, 50, 51 located opposite the output wheel 10, the driving member 6, and the supporting body 12, respectively. The individual portions may be interlocked in many manners, e.g. by means of a transverse through shaft 58, cf. Fig. 1 3. The individual portions may also be completely identical and be-provided with teeth both on the outer and on the inner side, cf. Fig. 12. These teeth are adapted so as to co-operate with teeth 52, 53, 54, 55, 56, and 57 on the components engaging the drawing means as previously described. As illustrated in the two Figures the running surface may be provided with recesses 59 and 60 opposite the spacing between the supporting body and the driving member and between the driving member and the output wheel, cf.Fig. 12, or opposite the spacing between the supporting body and the output wheel, cf. Fig. 13. In the latter case, only the portions of the drawing means cooperating with the supporting body 12 and the output wheel 1Q are identical, whereas the intermediate portion 50 of the drawing means comprises smooth peripheral surfaces, of which only the surface tuming inwards contacts a small portion, i.e. the driving member 6, of the gear.

As illustrated in Fig. 14, the drawing means may also be a fish joint chain comprising fish joints 61 interconnected by shafts 62. The fish joints may also, cf. Fig. 14, comprise teeth 63 engaging teeth 52 on the running surface of the housing. Usually the chain of fish joints comprises several fish joints situated side by side in the axial direction of the gear, and some of the fish joints may be provided with teeth 45 projecting inwards and engaging teeth 57 on the coaxially arranged supporting body as well as teeth 55 on the coaxial arranged output wheel. The fish joints may be formed in many ways, cf. Fig. 15. Some of the fish joints may be without teeth, whereas other fish joints may comprise teeth projecting radially inwards or teeth projecting radially inwards and outwards. Finally some fish joints may be provided with teeth projecting outwards.

The construction of a chain of fish joints in the axial direction of the gear may for instance be carried out as shown in Fig. 1 6. The fish joints, illustrated in Fig. 15 are used for forming a drawing means with various portions 49, 50, and 51 to be located opposite the output wheel 10, the driving member 6, and the supporting body 12, respectively. The various types of fish joints used for forming the chain of fish joints are in Fig.

16 illustrated by letters corresponding to the letters of Fig. 15. As illustrated in Fig. 16, the chain of fish joints is formed in such a manner that a circumferential recess in the inner wall of the chain of fish joints is shaped opposite the driving member for receiving the driving member 6. The middle row of fish joints opposite the driving member is of the type 61!illustrated in Fig. 15, which provides the chain of fish joints with a circumferential projection projecting inwards and being received by a circumferential recess 71 shaped therefor in the driving member. The recess in the chain of fish joints for receiving the driving member as well as the circumferential recess in the driving member for receiving the portion projecting inwards on the row of fish joints 61i prevent axial displacement of the chain of fish joints when the gear is in operation.As an additional securing, a row of fish joints 61! is also employed opposite a circumferential recess 72 in the output wheel, said recess receiving said row of fish joints.

For the sake of clarity, Fig. 16 only indicates every second row of fish joints, whereas the intermediate rows are only indicated by means of the reference numerals. It should furthermore be noted that the portions 49 and 51 of the chain of fish joints opposing the output wheel 10 and the supporting body 12 comprise teeth projecting inwards and engaging corresponding teeth 55 and 57 on the output wheel and the supporting body, respectively.

The drawing means may also be a chain of more solid chain links 70, e.g. of the type illustrated in Fig. 17 comprising teeth-forming projections 63 projecting outwards.

The invention has been described with reference to preferred embodiments both concerning the gear as well as concerning the components forming part thereof. Many modifications may, however, be performed without deviating from the scope of the invention.

The teeth on the engaging portions may for instance be formed in such a manner that the movable portions are provided with a displacement in the desired direction during the passage of the teeth into the teeth spacings. In a particular embodiment, the running surface may be provided with sixtyone teeth, the drawing means may comprise chains of thirty links with sixty teeth turning outwards and inwards, and the free-running supporting body and the drawn output wheel may be provided with fiftynine teeth, cf. Fig. 14.

Finally, the inner running surface on the housing may with respect to action be replaced by the peripheral surface on a stator wheel 80, cf. Fig.

1 8. As a result, it is rendered possible to use driving means, which are only adapted to engage the driving member 6, the output wheel 10, and the stator wheel 80 on the inner side thereof of the gear. In this case, many types of conventional driving means may be employed.

Fig. 18 illustrates an embodiment of a gear according to the invention, whereby a driving member is used comprising two parts 81 and 82.

By means of a securing member 83 these parts are secured to each other, and both parts are mounted on a common bearing bushing 84. This bearing bushing 84 is pivotably mounted on an eccentric 20 shaped on the input shaft 2 by means of ball bearings 85 and 86. The two parts 81 and 82 of the driving member are adapted to cooperate with their respective drawing means 7' and 7" shaped in the present embodiment as a chain provided with inner teeth. The first drawing means is as indicated furthermore adapted to cooperate with the above stator wheel, whereas the second drawing means co-operates with the output wheel 10. The stator wheel 80 is secured to the surrounding fixedly arranged housing by means of an appropriate securing member 87, whereas the output wheel 10 is secured to the output shaft 3 through a coaxial extension 88 thereon.

The chain 7' comprises more links or teeth than the stator wheel and preferably one more link or one more tooth than the stator wheel. A revolution of the input wheel 2 thereby implies that the chain 7' is displaced as many links as it exceeds the number of links of the stator wheel, forwards in the same direction.

The driving member 81 comprises less links or teeth, preferably three links less than the chain 7' A revolution of the input wheel therefore implies that the driving member 81 is forced to rotate as many links backwards in opposite direction relative to the chain.

The second chain 7" also comprises more links orteeth, preferably two links more than both the driving member 82 and the output wheel 10, whereas the driving member and the output wheel preferably comprise the same number of teeth As a result, a revolution of the input shaft 2 implies that the chain 7" moves as many links forwards relative to both the driving member 82 and the output wheel 10. Thus no mutual angular rotation takes place between the driving member 82 and the output wheel. These parts only perform the angular rotation transferred by the rotation of the driving member 81 about the input shaft or the eccentric, and this rotation is determined by the relations between the number of teeth on the stator wheel 80, the driving member 81, and the chain 7' surrounding said teeth.

Claims

1. gear comprising a driving input shaft, an output shaft coaxially situated relative thereto, and a housing with an inner running surface extending coaxially with the two shafts, characterised in that the input shaft comprises at least one annular driving member eccentrically arranged within the housing, which may rotate freely relative to the input shaft, and which is adapted to press an unstretchable, flexible, and endless drawing means against the inner running surface of the housing, and that the output shaft comprises at least one output wheel coaxially arranged within the housing and fixedly secured to the output shaft and furthermore adapted to mesh with the drawing means along an axial outer surface in such a manner that said drawing means is tightly arranged both about the annular eccentrically arranged driving member as well as about the output wheel, the drawing means, the surfaces thereof abutting the driving member, the inner running surface of the housing, and the output wheel being adapted in such a manner that substantially all types of mutual sliding movements are avoided at normal load.

2. Gear as claimed in claim 1, characterised in that the endless drawing means is formed as a belt or a chain.

3. Gear as claimed in claim 2, characterised in that the input shaft is provided with an annular supporting body rotatably and coaxially arranged within the housing and having the same diameter as the output wheel, and which is adapted to the supportingly mesh with a portion of the endless drawing means on the side of the eccentrically arranged driving member opposite the output wheel along a peripheral surface.

4. Gear as claimed in claim 3, characterised in that the driving member and the output wheel or when the supporting body is used, the output wheel and the supporting body comprise substantially radially projecting flange portions for preventing axial displacement of the drawing means.

5. Gear as claimed in claim 4, characterised in that the output shaft and the output wheel are integrally shaped in the form of a sleeve-shaped output shaft forming the bearing housing for the input shaft.

6. Gear as claimed in claim 5, characterised in that the sleeve-shaped output shaft is secured to a motor housing and the input shaft is coupled to the motor shaft.

7. Gear as claimed in claim 3, characterised in that it comprises several eccentrically arranged driving members with their respective drawing means of an individual length and eccentricity, that the running surface is shaped on rotatable rings adapted to co-operate with their respective drawing means and to selectively lock against rotation by means of locking devices activatable from the outside, and that the drawing means of one driving member co-operates with the sleeveshaped output wheel integrally shaped with the supporting body at the first drawing means.

8. Gear as claimed in claim 7, characterised in that the housing is provided with radial, transverse apertures in the portions(s) forming the running surfaces.

9. Gear as claimed in claim 8, characterised in that the drawing means is a belt with an inserted ribbon-shaped reinforcement provided with apertures.

10. Gear as claimed in claim 9, characterised in that the drawing means is a belt with a circumferential wire reinforcement and a transverse steel needle reinforcement.

11. Gear as claimed in claim 10, characterised in that the drawing means comprises transverse recesses increasing the friction.

12. Gear as claimed in claim 10, characterised in that the drawing means is provided with transverse teeth on the radially inner and/or outer side.

13. Gear as claimed in claim 12, characterised in that the side turning radially inwards of the drawing menas comprises a circumferential continuous recess or a circumferential projection adapted to co-operate with the driving member.

14. Gear as claimed in claim 13, characterised in that the drawing means comprises one or several circumferential recesses on the outer side.

15. Gear as claimed in claim 14, characterised in that the running surface of the housing, the peripheral surface of the driving member and/or the peripheral surfaces of the output wheel and of the supporting body comprise teeth for meshing with the transverse recesses or teeth on the drawing means.

1 6. Gear as claimed in claim 15, characterised in that the drawing means comprises several, perferably identical, circumferential portions co operating with the output wheel, the driving member, and the supporting body, respectively.

17. Gear as claimed in claim 16, characterised in that the running surface is provided with one or several circumferential recesses separating the portions of the running surface meshing with their respective circumferential portions of the drawing means.

18. Gear as claimed in claim 1 7, characterised in that the running surface of the housing only meshes with the drawing means along the portions of the drawing means also meshing with the supporting body and the output wheel.

19. Gear as claimed in claim 18, characterised in that the various parts of the drawing means are mutually connected by means of transverse, through shafts.

20. Gear as claimed in claim 19, characterised in that the number of teeth on the running surface is higher, preferably one more, than the number of teeth on the side of the drawing means cooperating therewith, and that the number of teeth on the output wheel and the supporting body is lower, preferably one less, than the number of teeth on the side of the drawing means CO- operating therewith.

21. Gear as claimed in claim 20, characterised in that the drawing means is a chain of chain fish joints coherent both lengthwise and crosswise the drawing means.

22. Gear as claimed in claim 21, characterised in that the driving member and the drawing means are adapted to co-operate with a running surface shaped on the outer peripheral side of a stator wheel.

23. Gear as claimed in claim 22, characterised in that the driving member comprises two mutually connected parts, and the drawing means comprises two chains, one of said chains being adapted to co-operate with one part of the driving member and the running surface of the stator wheel, whereas the second chain is adapted to cooperate with the second part of the driving member and the output wheel.

24. Gear substantially as described above with reference to the accompanying drawing.