Abstract:
A shaft for rotationally coupling a main device to a tubular device includes a first free end that is configured to be introduced into the tubular device, and a second end configured to be secured to the main device. The shaft also defines at least a first bearing region along an outer circumference that is configured to form a contact in a hollow accommodating region of the tubular device, and further includes at least one torque-transmitting section configured to engage with a torque-transmitting section of the tubular device. A securing device of the shaft includes a locking device that, in a locked state, is configured to prevent the securing device from being dismounted, and that, in an unlocked state, is configured to enable the tubular device to be dismounted. The securing device further includes an interlocking device that is arranged on the first end of the shaft, and that enables locking and unlocking the locking device.

Description:
PRIOR ART 
       [0001]    The invention is based on a shaft for rotationally coupling a main device to a tubular device according to the generic type of the independent claim. 
         [0002]    DE 102 11 371 A1 discloses a shaft for rotationally coupling a main device to a tubular device such that a torque can be transmitted by means of the shaft between the main device and the tubular device to be mounted, wherein the shaft has a first, free end which is provided to be introduced into the tubular device for the mounting, wherein the shaft can be fastened, at least by the second end thereof that faces away from the first end, to the main device, wherein the shaft has, along the outer circumference thereof, at least one first supporting region which is provided to come into contact in a hollow receiving region of the tubular device when the tubular device is mounted on the shaft, wherein the shaft has, along the outer circumference thereof, at least one torque-transmitting section which is provided to come into engagement with a torque-transmitting section of the tubular device, and wherein at least one securing device is arranged on the shaft at least for the axial securing of the tubular device on the shaft. 
         [0003]    As a result, rapid mounting and removal are possible. However, the axial retaining force with which the tool is retained on the shaft is restricted to the force with which an operator can still mount and remove the tool within an ergonomically expedient region. This force is relatively small. If the tool, for example, experiences an impact during operation counter to the action of the retaining force of the securing device, the still rotating tool may jump off the shaft, which in particular can also be referred to as unintentional removal. 
       DISCLOSURE OF THE INVENTION 
     Advantages of the Invention 
       [0004]    By contrast, the shaft for rotationally coupling a main device to a tubular device with the features of the independent claim has the advantage that a mounted tubular device is secured against unintentional removal, but, nevertheless, easy mounting and/or removal of the device is possible. 
         [0005]    This is achieved by a shaft for rotationally coupling a main device to a tubular device such that a torque can be transmitted by means of the shaft between the main device and the tubular device to be mounted, wherein the shaft has a first, free end which is provided to be introduced into the tubular device for the mounting, wherein the shaft can be fastened, at least by the second end thereof that faces away from the first end, to the main device, wherein the shaft has, along the outer circumference thereof, at least one first supporting region which is provided to come into contact in a hollow receiving region of the tubular device when the tubular device is mounted on the shaft, wherein the shaft has, along the outer circumference thereof, at least one torque-transmitting section which is provided to come into engagement with a torque-transmitting section of the tubular device, and wherein at least one securing device is arranged on the shaft at least for the axial securing of the tubular device on the shaft, wherein a blocking device is arranged on the securing device, said blocking device being provided in order, in a locked state, to block the tubular device against removal from the shaft and, in an unlocked state, to permit removal of the tubular device from the shaft, wherein a locking device with which the blocking device can be unlocked and can be locked is provided on the securing device, and in that the locking device is arranged at the first end of the shaft. 
         [0006]    Advantageous developments and improvements of the shaft indicated in the independent claim are possible by means of the measures cited in the dependent claims. 
         [0007]    Simple mounting is provided when the shaft can be introduced together with the blocking device and the locking device into the tubular device. 
         [0008]    Mounting which is likewise simple is produced when the blocking device has a radially protruding retaining section for a tubular device mounted on a shaft, which retaining section can be guided through the hollow receiving region when the device is mounted. 
         [0009]    It is advantageous for the removal when the securing device remains on the shaft at least when the tubular device mounted on the shaft is removed. 
         [0010]    It is advantageous for the mounting and removal when the securing device takes up a locking position in the locked state and an unlocking position in the unlocked state, and when the locking position and the unlocking position are spaced apart radially and/or tangentially and/or axially on the shaft. 
         [0011]    A secure hold is provided when, for contact against at least one shoulder of the tubular device, the blocking device has at least one retaining section which preferably, at least in the locked state, has a radial excess length with respect to an outer surface of the shaft, which outer surface is adjacent to the blocking device. 
         [0012]    A compact design is produced when the shaft has a groove emerging from the first end, from the groove base of which the blocking device projects, at least in the locked state, wherein, in the event of a plurality of grooves, a blocking device is preferably provided only in one groove base. 
         [0013]    A compact construction is likewise produced when the locking device is arranged on the end side of the first end of the shaft. 
         [0014]    Easy operability is produced by the fact that the securing device can be transferred from the locked into the unlocked state by axial pressing of the actuating element against the shaft or rotation of the actuating element about a longitudinal axis of the shaft. 
         [0015]    It is particularly advantageous in relation to tubular devices fastened by means of customary screw connections when the locking device is rotated between a locking position and an unlocking position of the securing device by less than 360°, preferably 180°. 
         [0016]    Simple and rapid operability is produced by the fact that the blocking device can be unlocked manually and automatically locks, but, in the locked state, permits the mounting of a tubular device. This is improved even further when the blocking device is kept in the locked state by means of an elastic force. 
         [0017]    A compact construction is produced when the securing device is fastened in an axial recess, preferably a longitudinal bore, emerging from the end side of the first end, and the axial recess has, on the end side, a cross-sectional area which is substantially constant over the length of the recess, over which the securing device extends in the shaft, or which tapers in the direction of the second end of the shaft. A secure hold of the tubular device is provided when, in the locked state, the blocking device is preferably acted upon with a force which acts outward transversely with respect to the axial recess. 
         [0018]    A cost-effective design is produced by the fact that the axial recess has a base on which a spring is arranged, said spring exerting, preferably via a ramp, a force which acts outward axially and acts on the locking device and/or the blocking device. 
         [0019]    Easy production is produced when a lateral recess is arranged transversely with respect to the axial recess, said lateral recess having a first opening and a second opening on the outer circumference, wherein the second opening is larger than the first opening, and in that the blocking device projects outward from the first opening. 
         [0020]    A simple construction is provided when the force, in particular spring force, acts in such a manner that the securing device attempts to press out of the first end of the shaft, and in that the securing device is kept in the shaft by the blocking device. 
         [0021]    A structurally favorable realization is produced by the fact that the securing device comprises a, preferably pin-shaped, bearing device, in which the, preferably spherical, blocking device is arranged, wherein a ramp by means of which the blocking device is movable radially and which is at a distance from the outer circumference of the shaft that increases from the second to the first end of the shaft is preferably formed in the bearing device such that, when the bearing device is displaced into the shaft from the first to the second end, the blocking device can move away from the outer circumference. 
         [0022]    A radially compact shaft, in particular for a hand-held machine tool, is produced when the ratio of the width of the grooves to the diameter of the first supporting region  46  is 30 to 60%, preferably 40 to 50%. 
         [0023]    Furthermore, it is advantageous for a radially compact shaft which can transmit a high torque when the at least first supporting region has a diameter of 11.7 mm and the at least one groove has a width of 5.2 mm and in particular a length of 23.8 mm, starting from an end side of the shaft, wherein there are preferably four grooves which are arranged distributed uniformly on the circumference and of which in each case two diametrically opposite grooves are at a distance of 8.55 mm. As a result, specifically in the case of a tubular device made from plastic, the surface pressure is not too high. 
         [0024]    An axially compact shaft is produced when the first supporting region has a length of at least 30 mm, preferably 48.4 mm, starting from an end side of the shaft, and the first supporting region is preferably adjoined by a second supporting region which has a larger diameter than the first supporting region, wherein the length of the first supporting region and the length of the second supporting region are in particular 63.5 mm. 
         [0025]    A method for producing a shaft is particularly advantageous, in which the blocking device is inserted into the securing device, wherein a spring is inserted into the recess, wherein after the spring is mounted in the shaft, the securing device is pushed together with the blocking device until the blocking device protrudes through the first opening, and therefore the securing device is mounted in the shaft, and wherein a cap acting as an actuating device is preferably placed onto the end protruding from the shaft. 
         [0026]    A machine tool, in particular hand-held machine tool, with a shaft according to the invention which has a receptacle for the shaft, via which receptacle the shaft is drivable at least in a rotating and/or oscillating manner, has the advantage that tools can easily be mounted and removed. Furthermore, they have the advantage that tools are held securely. 
         [0027]    The device according to the invention also makes it easily possible to realize a system which furthermore comprises a machine tool and at least one tubular device which is drivable by the machine tool and which preferably comprises a tool, wherein the system preferably comprises a set of tubular devices which are optionally drivable by the machine tool. In such a system, individual tools can be rapidly interchanged. Nevertheless, the tools are held securely. 
     
    
     
       EMBODIMENTS OF THE INVENTION 
         [0028]    Exemplary embodiments of the invention are illustrated in the drawings and explained in more detail in the description below, in which: 
           [0029]      FIG. 1  shows a machine tool with a first exemplary embodiment of a shaft, 
           [0030]      FIG. 2  shows a partial view of the machine tool from  FIG. 1  with a grinding roller mounted on the shaft, 
           [0031]      FIG. 3  shows a side view from the left and a view of the end side of the grinding roller and the shaft according to  FIG. 2 , 
           [0032]      FIG. 4  shows a perspective view of the shaft without the grinding roller, 
           [0033]      FIG. 5  shows an end view of the grinding roller without the shaft, 
           [0034]      FIG. 6  shows a side view of the shaft by itself, 
           [0035]      FIG. 7  shows a longitudinal section through the shaft, 
           [0036]      FIG. 8  shows a perspective longitudinal section through a sleeve according to the intercepting line VIII in  FIG. 9 , 
           [0037]      FIG. 9  shows a first end side of the sleeve, 
           [0038]      FIG. 10  shows the second end side of the sleeve, 
           [0039]      FIG. 11  shows a longitudinal section through the sleeve according to the intercepting line XI in  FIG. 9 , 
           [0040]      FIG. 12  shows a longitudinal section through the sleeve according to the intercepting line XII in  FIG. 9 , 
           [0041]      FIG. 13  shows a perspective longitudinal section through a shortened sleeve, 
           [0042]      FIG. 14  shows a perspective view of a pin-shaped bearing device, 
           [0043]      FIG. 15  shows a perspective view of an actuating cap, 
           [0044]      FIG. 16  shows a side view of the actuating cap, 
           [0045]      FIG. 17  shows a front view of the actuating cap, 
           [0046]      FIG. 18  shows a longitudinal section through the grinding roller and shaft during the mounting, 
           [0047]      FIG. 19  shows a longitudinal section through the grinding roller and shaft in a mounted state, and 
           [0048]      FIG. 20  shows a longitudinal section through the grinding roller and shaft in a first state during the removal. 
       
    
    
     DESCRIPTION 
       [0049]      FIG. 1  shows a main device designed as a hand-held machine tool  10 , as disclosed, for example, in WO 2012/052242 A2. However, the machine tool  10  can also be designed as a machine tool which is stationary or is semi-stationary, i.e. suitable for carrying on construction sites. The machine tool  10  is designed as a power unit, but a battery-operated design is also conceivable. The machine tool  10  can be used, for example, as a roll grinder or else saw with a rotating and/or oscillating output. 
         [0050]    The machine tool  10  has a housing  12  in which a drive motor (not illustrated) is arranged. The housing  12  has an elongated shape and can be held with one hand or two hands. An elongate, hollow neck  14  is arranged at one end of the housing. The longitudinal axis of the neck  14  is slightly inclined with respect to the longitudinal axis of the housing  12 . However, the longitudinal axis of the neck  14  can also be arranged more steeply than, in parallel to or in alignment with the longitudinal axis of the housing  12 . A transmission shaft  16  (indicated in  FIGS. 4 and 5 ) or a differently designed transmission element, for example a belt, is arranged in the neck  14 . An output head  18  is formed at that end of the neck  14  which is remote from the housing  12 . The output head  18  can also be arranged directly on the housing  12 . In this case, a neck  14  would not be present. It is also possible for an output head  18  not to be present. 
         [0051]    A shaft  20  designed as an output shaft is arranged in the output head  18  by means of a receptacle  19 . The shaft  20  can be fastened in the receptacle  19  in such a manner that destruction-free removal is no longer possible. However, it is preferred that the shaft  20  is arranged removably in the receptacle  19  for maintenance or repair purposes. The central longitudinal axis or longitudinal axis  22  of the shaft  20  runs perpendicularly to the longitudinal axis of the housing  12  and forms a plane with said longitudinal axis. However, the longitudinal axis  22  of the shaft  20  can also run at a different angle with respect to the longitudinal axis of the housing  12  and/or so as not to form a plane with said longitudinal axis. The shaft  20  is drivable in a rotatory and/or oscillating manner. An axial movement, such as, for example, in the manner of a jigsaw, is also possibly conceivable. The axial movement can also be combined with the rotatory and/or oscillating movement. It is also conceivable that the shaft  20  is not driven via the transmission shaft  16 , but rather drives the transmission shaft  16 . The machine tool  10  or a differently designed main device, for example a dynamo, can also be driven in this case. 
         [0052]      FIGS. 2 and 3  show a roller  24  mounted on the machine tool  10  or on the shaft  20 . The roller  24  is mounted on the shaft  20  by means of a tubular device designed as a sleeve  30 . The shaft  20  therefore serves for the rotational coupling of the machine tool  10  to the sleeve  30 , and therefore a torque can be transmitted between the machine tool  10  and the sleeve  30 . 
         [0053]    In the present exemplary embodiment, the roller  24  is made from rubber. An abrasive paper belt or polishing belt (not shown) can be fastened on the roller  24 . Slots  26  running in the longitudinal direction are formed on the circumference of the roller  24 . However, instead of the roller  24  which is shown, a different tool can also be provided, for example a lamella grinder, a brush in the form of a wire brush, nylon brush or “Fladder” brush. Instead of the roller  24 , a saw blade, a saw blade segment, another disc serving, for example, for grinding, or a disc segment can also be provided. 
         [0054]    The roller  24  is arranged on the tubular device designed as the sleeve  30 . The roller  24  can be an individual component or an assembly. The sleeve  30  can likewise be an individual component or an assembly. However, in the present exemplary embodiment, the roller  24  and the sleeve  30  are formed as a single part, as taken on their own in each case. It should be emphasized that the sleeve  30  can also be an integral part of the roller  24  and the roller  24  can be an integral part of the sleeve  30 . If the roller  24  and the sleeve  30  are separate components or assemblies, the roller  24  can be fastened on the sleeve  30  removably or non-removably. In the case of a removable fastening, the roller  24  can be fastened on the sleeve  30  by press fit, screw connection, latching connection or quarter-turn connection. In the case of a fastening which is not provided for the removal, the roller  24  can be adhesively bonded, ultrasonically welded and/or pressed onto the sleeve  30 . However, the last-mentioned fastenings can also be designed in such a manner that the roller  24  and sleeve  30  are nevertheless releasable again from each other without having to be destroyed. The roller  24  and the sleeve  30  can also be potted or insert molded with each other. For example, the roller  24  can be made from plastic and the sleeve  30  from metal, or vice versa, wherein the plastic is applied to the metal by means of a plastics injection molding process. The two components can also be made from plastic or metal or another suitable material. In the present exemplary embodiment, the sleeve  30  is designed as a plastics injection molded part. 
         [0055]      FIG. 4  shows a first, free end  31  of the shaft  20  in an end view, and  FIG. 5  shows the roller  24  together with the sleeve  30  in an end view. Mutually corresponding cross-sectional surfaces of the shaft  20  and of the sleeve  30  can readily be seen. As a result, it can be ensured that sleeves  30  which are provided only for mounting on the shaft  20  can be mounted on the shaft  20 . 
         [0056]    It is likewise also clear from  FIG. 4  that a cap  32  is arranged on the end side of the first end  31  of the shaft  20 . In addition, a blocking device designed as a ball  34  is provided, wherein the cap  32  and ball  34  are part of a securing device  36 . The securing device  36  serves at least for axially securing the sleeve  30  on the shaft  20  following the mounting. For the mounting, the shaft  31  can be introduced with the first end  31  in front into the sleeve  30 ; the first end  31  is therefore the free end of the shaft  20 . The shaft  20  together with the cap  32  and the ball  34  can be introduced here together into a hollow receiving region  38  (shown in  FIG. 5 ) of the sleeve  30 , which facilitates the mounting. Four inwardly directed webs  39  which run in the longitudinal direction of the receiving region  38  and of the sleeve  30  are advantageously formed in the hollow receiving region  38 . 
         [0057]    In addition to  FIG. 4 ,  FIGS. 6 and 7  show further details of the shaft  20 . The shaft  20  preferably has a length of 89.6 mm. It should be emphasized that this dimension and also the following dimensions can include customary manufacturing tolerances of up to a few tenths of millimeters. The shaft  20  comprises a journal  40 , a stepped intermediate region  42  and a mounting region  44 . The journal  40  is provided at the second end  37  which faces away from the first end  31 . The journal  40  preferably has a length of 15 mm and a diameter of 7 mm. The journal  40  is mounted in the receptacle  19  preferably via an interference fit. The shaft  20  is fastened to the machine tool  10  or output head  18  by the journal  40 . The journal  40  of the shaft  20  is adjoined by a stepped intermediate region  42  with a length of preferably 11 mm, which intermediate region forms a transition from the diameter of the journal  40  to the comparatively larger diameter of the mounting region  44 . The sleeve  30  is arranged on said mounting region  44 . 
         [0058]    The mounting region  44  preferably has a length of 63.5 mm. Starting from the first end  31 , a first supporting region  46  is provided on the mounting region  44  and along the outer circumference of the shaft  20 , said supporting region  46  being arrangeable in the hollow receiving region  38  of the sleeve  30  when the sleeve  30  is mounted on the shaft  20 . The first supporting region  46  has a length of 48.4 mm and a diameter of preferably 11.7 mm. A second supporting region  48  is preferably formed between the first supporting region  46  and the intermediate region  42 . The second supporting region  48  has a somewhat larger diameter than the first supporting region  46  of preferably 12.1 mm. The diameters of the supporting regions  46  and  48  are preferably manufactured particularly precisely. 
         [0059]    Starting from the first end  31  of the shaft  20 , four grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  which are offset by 90° in each case run on the outer circumference of said shaft parallel to the longitudinal axis  22  or in the longitudinal direction of the shaft  20 . These grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  constitute torque-transmitting sections of the shaft  20 . In the present exemplary embodiment, four grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  are provided, which is advantageous for the mounting. However, it is also conceivable for two, three or more than four grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  to be formed on the outer circumference of the shaft  20 . For example, a different number of grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  can be provided for different power classes of machine tools  10 , when more grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  are provided for higher power classes. At the higher power classes, it is possible, for example, for a higher torque to be transmitted. 
         [0060]    In the present exemplary embodiment, the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  have a rectangular cross-sectional area. The grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  have a width of preferably 5.2 mm and a length of 23.8 mm. The distance of a groove base  52  of a first groove  50 . 1  or  50 . 2  from the groove base  52  of a second, diametrically opposite groove  50 . 3  or  50 . 4  is preferably 8.5 mm. In other words, the wrench size of two diametrically opposite groove bases  52  is preferably 8.5 mm. The distance of a groove base  52  of a groove  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  from the longitudinal axis  22  of the shaft  20 , wherein the longitudinal axis  22  in this case means the center axis of the shaft  20 , is therefore around 4.25 mm. Since the width of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4 , is 5.2 mm and the diameter of the first supporting region  46  is 11.7 mm, the proportion of the width to the diameter is around 44%. It has proven advantageous when the proportion of the width of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  to the diameter of the first supporting region  46  is 30 to 60%, preferably 40 to 50%. This produces a compact construction and low surface pressure. A good torque can therefore also be transmitted in particular to a sleeve  30  made from plastic without the surface pressure becoming too great. 
         [0061]    At the groove end  53  of said grooves that is opposite the first end  31  of the shaft  20 , the side surfaces  54  of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  preferably form a semicircle, the radius of which corresponds to half of the width of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4 . This is the preferred embodiment with regard to manufacturing and mounting. However, the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  can also be designed in such a manner that the groove base  52  peters out in an arc of a circle with respect to the outer circumference of the groove  20 . Instead of the first-mentioned semicircular groove end  53 , a side running perpendicularly to the side surfaces  54  and groove base  52  could also be provided. It is also possible for the side surfaces  54  of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  not to run parallel to one another, as shown, but rather to be inclined with respect to one another. The grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  can each therefore also have a different cross-sectional areas—for example, a trapezoidal cross-sectional area, in particular in the form of a dovetail, or a triangular or rounded cross-sectional area. 
         [0062]    Starting from the end side of the first end  31 , an axial recess designed as a longitudinal bore  56  is provided in the shaft  20 . The longitudinal bore  56  preferably has a diameter of 6.05 mm. However, it can also have a stepped or conical profile. The longitudinal bore  56  is a blind bore with a conical end. However, it can also be designed as a flat base blind bore. The longitudinal bore  56  can also be designed as a through bore with a constant, conical or stepped diameter. In addition to the round cross-sectional area, another cross-sectional area, for example a polygonal or oval cross-sectional area, can also be provided. 
         [0063]    At a distance of 6.8 mm from the end side of the ends  31  of the shaft  20 , a lateral recess which is designed as a transverse bore  58  and extends from the groove  50 . 1  to the groove  50 . 3  is provided perpendicularly to the longitudinal bore  56  or the longitudinal axis  22 . The transverse bore  58  has a first opening  60  and a second opening  62  on the outer circumference of the shaft  20 . The second opening  62  is preferably larger than the first opening  60 . The second opening  62  preferably has a diameter of 4.1 mm, and the first opening  60  on the groove base  52  has a diameter of 3.65 mm. The opening  60  is formed in the groove base  52  of the groove  50 . 1  and the second opening  62  is formed in the groove base  52  of the diametrically opposite groove  50 . 2 . However, it is also possible for the transverse bore  58  together with the openings  60 ,  62  thereof to be formed at a different location on the shaft  20 . The second opening  60  is smaller because a drill with a conical point, coming from the second opening  62 , is not entirely guided through the groove base  52  of the groove  50 . 1  during the production. This results in a section of the first opening  60  that encases the side surface of a truncated cone. As a result, a part of the ball  34 , which preferably has a diameter of 4 mm for this purpose, or a differently designed blocking device projects out of the first opening  60 , but the ball  34  is secured against dropping out. However, this can also be achieved by the fact that only the first opening  60  is provided. It is also conceivable for the opening  60  to be drilled with a diameter which permits the ball  34  to be inserted. After the insertion, the first opening  60  is then calked. Instead of one transverse bore  58  or one first opening  60 , it is also possible to provide a plurality of transverse bores  58  or first openings  60  which are arranged, for example, axially one behind another. Preferably, however, just one transverse bore  58  or first opening  60  is provided. 
         [0064]      FIGS. 8 to 12  show further details of the sleeve  30 . A sleeve  30   a  which is shortened in comparison to the sleeve  30  and is shown in  FIG. 13  is also already referred to. Parts, regions or sections of the shortened sleeve  30   a  that are identical to the sleeve  30  according to  FIGS. 8 to 12  are provided with the same reference numbers. 
         [0065]    As already explained, the sleeve  30  is a tubular device for connection to the shaft  20 , and therefore a torque can be transmitted by means of the shaft  20  between the machine tool  10 —or a differently designed main device—and the sleeve  30 . In the present exemplary embodiment, the torque is transmitted to the roller  24  by the sleeve  30 . In contrast to a disc-shaped device, a tubular device is distinguished in that the length of the tubular device is greater than the diameter. In particular, the length of a tubular device or of the sleeve  30  is greater than the inside diameter thereof, which will also be discussed in detail. The shaft  20  and the securing device  36  therein can therefore be formed in a manner saving on space radially. In addition, a roller  24  can be securely attached to the tubular device or sleeve  30  since a larger supporting surface is produced. However, even in the case of a sleeve  30  and roller  24  of integral design, significantly lower loadings of the material due to, for example, surface pressure and/or shearing stresses arise. 
         [0066]    The sleeve  30  has a length of 60 mm. The outer circumference is substantially cylindrical and has an outside diameter of 16.05 mm. The sleeve  30  has at least one hollow receiving region  38  for the first and second supporting regions  46 ,  48  of the shaft  20 . Alternatively, two receiving regions  38  which run in parallel and into which two parallel shafts  20  are inserted could also be provided. However, the simple design is preferred. 
         [0067]    The hollow receiving region  38  preferably extends over the entire length of the sleeve  30  and is advantageously open on the two end sides—or ends— 64  and  66  of the sleeve  30 . A mounting opening  68  of the hollow receiving region  38  or of the sleeve  30  is located on the first end side  64 . An operating opening  70  of the hollow receiving region  38  or of the sleeve  30  is located on the second end side  66 . For the mounting of the sleeve  30  or of a roller  24  or another device on the shaft  20 , the sleeve  30 , with the mounting opening  68  in front, is placed onto the shaft  20 , which is also discussed in greater detail. 
         [0068]    In the region of the operating opening  70  or in the vicinity of the second end side  66 , two bumps in the form of wall sections  71  which reach into the hollow receiving region  38  are indicated by dashed lines on the inner circumference of the sleeve  30 . However, said wall sections  71  can also be omitted. It is also possible for only one wall section  71  or more than two to be provided. It is also possible for a number of wall sections  71  corresponding to three, four or up to another number of webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to be provided. The wall sections  71  serve as blocking sections against mounting the sleeve  30  with the wrong orientation, that is to say, onto the shaft  20  with the operating opening  70  in front. 
         [0069]    The wall sections  71  are at a smaller distance from the longitudinal center axis or longitudinal axis  73  of the sleeve  30  than the radius of the first supporting region  46  of the shaft  20 . The wall sections  71  are formed between two adjacent webs  39 . 1  and  39 . 4  and also  39 . 2  and  39 . 3 . They preferably have an extent of 1-2 mm in the longitudinal direction of the sleeve  30 . The wall sections  71  are located adjacent to the second end side  66  or at the beginning there of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 . Instead of the wall sections  71  formed between the webs  39 . 1  and  39 . 4  and also  39 . 2  and  39 . 3 , differently shaped elevations can also be provided as blocking devices against mounting the sleeve  30  with the wrong orientation. For example, the side surfaces  54  of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  can taper in the direction of the groove ends  53 , and the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  can have a geometry which is adapted thereto by said webs likewise becoming narrower in the direction of the mounting opening  68 . The profile here can be continuous or with steps. 
         [0070]    The receiving region  38  of the sleeve  30  has at least one first contact surface  72  for the radial mounting on the first supporting region  46  of the shaft  20 . The contact surface  72  can emerge directly from the second end side  66  of the sleeve  30 . However, in the present exemplary embodiment, an intermediate region  74  which has a somewhat larger inside diameter is formed between the first end side  66  and the contact surface  72 . The intermediate region  74  emerges from the second end side  66  and has a length  76  of 20 mm minus the resulting length  78  of a hollow  80  formed in the end side  66 . The hollow  80  encloses an angle of 90°. The contact surface  72  has an inside diameter of 11.8 mm and extends over a length  82  of 10 mm. If the sleeve  30  is designed as an injection molded part, there is preferably no mold release slope on the contact surface  72 . 
         [0071]    Starting from the end side  66  or the end of the hollow  80 , four bumps which are distributed uniformly on the inner circumference and are designed as walls or webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  run in the longitudinal direction in the sleeve  30 . The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  are therefore arranged offset by 90° with respect to one another. The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  divide the contact surface  72  into partial surfaces  86 . 1 ,  86 . 2 ,  86 . 3 ,  86 . 4  which are preferably identical in size. Since the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  do not reach in the longitudinal direction entirely as far as the contact surface  72 , the partial surfaces  86 . 1 ,  86 . 2 ,  86 . 3 ,  86 . 4  are also connected to one another at the ends thereof pointing in the direction of the first end side  64  via a strip on the inner circumference of the sleeve  30 . Instead of the preferred uniform distribution of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  on the inner circumference of the sleeve  30 , other distributions are also possible. Instead of the four webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , a different number can also be provided. Therefore, at least two, in particular three, preferably four webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  can be arranged on the inner circumference. One web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  by itself is also possible. More than four webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , for example five, six, seven, eight or more webs, can likewise be provided; however four are preferred. 
         [0072]    It is therefore at least provided that the sleeve  30  has at least one torque-transmitting section, preferably in the form of a wall or a web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , which can be brought into engagement with at least one a torque-transmitting section, preferably in the form of a groove  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  of the shaft  20 . The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  are bumps of the sleeve  30 , which bumps emerge from the contact surface  72  and project into the hollow receiving region  38 . Instead of bumps of the sleeve  30  in the form of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , differently shaped walls or wall sections can also be provided as torque-transmitting sections. It also suffices when at least one such bump of the sleeve  30  is provided. The at least one bump is preferably formed integrally with the sleeve  30 . It is accordingly an integral part of the sleeve  30 . The sleeve  30  together with the at least one bump or the at least one web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , wherein, preferably, four bumps or four webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  are provided, is preferably produced in an injection molding operation. It is also possible for one web or for a plurality of webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to be produced from a different material than the remaining sleeve  30 . For example, metal can be provided as the material for the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , said metal being inserted as an insert into a plastics injection molding die and being insert molded with the material of the sleeve  30 . It is also possible for the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to be pressed into recesses in the wall of the sleeve  30 . Furthermore, it is also conceivable for the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to be adhesively bonded into the sleeve  30  or recesses of the sleeve  30 . 
         [0073]    Fastening of the web or of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  in the sleeve  30  or in recesses of the sleeve  30  by means of ultrasonic welding is also possible. Of course, it is possible for the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to be able to be released from the sleeve  30  without destroying the sleeve or the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 . The various formations result in the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  or a differently designed bump being held immovably in the sleeve  30 . As a result, simple mounting of the sleeve  30  on the shaft  20  is possible. 
         [0074]    In addition, the web or the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  or a differently designed bump is or are captive. 
         [0075]    The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  have parallel side walls  87  with a width of 5.05 mm. Between the side walls  87 , surfaces  88  are formed in the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 . The distance between the surfaces  88  of two diametrically opposite webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  is preferably 8.65 mm. The distance of a web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  or of the surface  88  of a web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  from the center axis of the sleeve  30  is 4.325 mm. As already mentioned, the contact surface  72  has an inside diameter of 11.8 mm. A proportion of the distance of a web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  from the longitudinal axis  73  of the sleeve  30  to the diameter of the contact surface is therefore around 37%. This results in a compact radial construction of the sleeve  30 . Advantageous values for the proportion of the distance of a web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  from the longitudinal axis  73  of the sleeve  30  to the diameter of the contact surface  72  also lie between 25 to 50%, in particular 30 to 45%, preferably 35 to 40%. The width of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  of 5.05 mm results in a proportion of around 43% to the diameter, which is 11.8 mm, of the first contact surface  72 . This proportion in combination with the proportion of distance of the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  from the inside diameter of the mounting surface  72  results in a favorable cross-sectional area of the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , wherein further recesses can also be formed in the cross-sectional area of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , which will also be discussed below. Furthermore, good values for the cross-sectional area of the web or of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  are produced when the proportion of the width of the web or of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to the diameter of the first contact surface  72  is between 30 and 60%, in particular 40 and 50, preferably 40 and 45%. 
         [0076]    The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  are 29.35 mm in length. They therefore extend over at least part of the overall length of the sleeve  30 . The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  begin at the transition from the first end side  64  to the hollow receiving region  38  of the sleeve  30 , which receiving region, as shown in the present exemplary embodiment, is preferably provided with the hollow  80 . Instead of the parallel side walls  87  which are shown, the latter can also be inclined with respect to one another, and therefore the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  also have a trapezoidal or triangular cross-sectional area on the outer sides thereof. The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  can also be rounded. The length of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  of 29.35 mm means that said webs are around 2.5 times as long as the diameter of the first mounting surface  72 . This results in a particularly favorable surface pressure for the size of the side walls  87 . Further advantageous values are produced when the length of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  is twice to three times as long as the diameter of the first mounting surface  72 . 
         [0077]    A groove  90  running in the longitudinal direction of the sleeve  30 , preferably parallel to the longitudinal axis  73 , is in each case formed in the surface  88  of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , which surface faces the center axis of the sleeve  30 . The groove  90  has a length  92  of 14.4 mm. The groove  90  which runs over part of the length of the web  39  and the depth of which is preferably smaller than the height of the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  preferably has a rounded cross-sectional area. The radius of the rounding is 1 to 5 mm, preferably 1 to 3 mm. Particularly preferably, the radius is 2 mm and is therefore half the diameter of the ball  34 . The size of the groove  90  is selected in such a manner that a flat residual area of the surface  88  still remains, the width of which residual area is preferably 0.5 to 1 mm in each case. 
         [0078]    The groove  90  ends in a wall  94  which preferably runs in a plane which is perpendicular to the longitudinal axis  73  of the sleeve  30 . The wall  94  therefore preferably forms a stop for the ball  34  or for another securing device  36  arranged on the shaft  20 . Instead of the flat wall  94  shown, the end of the groove  90  can also be designed in the same manner as the groove end  53 . 
         [0079]    The length  93  of the respective web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  or of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  is 14.95 mm from the wall  94  as far as the end of the web facing away from the end side  66 . More generally, the length  93  of the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  is 14.95 mm from the end of the groove  90  as far as the end thereof facing away from the end side  66 , which can easily be produced even with walls  94  which are not flat. This results in the already mentioned overall length of the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  of 29.3 to 29.4 mm. However, the accuracy of the length  93  is preferably greater than the overall length. 
         [0080]    The groove  90  or the wall  94  is adjoined by a ramp  96  which preferably runs in the groove  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  and is inclined in such a manner that it goes away from the center axis of the sleeve  30 . The width of the ramp  96  is 2 to 5 mm, preferably 3 to 4 mm. As a result, two residual areas of the surface  88  of the respective web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  still remain to the side of the ramp  96 , as seen in the longitudinal direction. A step  98  is formed between the end of the ramp  96 , which end also forms that end of the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  which is remote from the first end side  64 , and the contact surface  72 . The step  98  is produced from the petering-out side walls  87  which are rounded at the end with a radius which corresponds to half the width of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , i.e. 2.5 mm. Instead of the oblique ramp  96  shown, a stepped ramp can also be provided. It is also possible for there not to be a ramp  96 . In this case, the web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  can have a uniformly flat surface  88 . 
         [0081]    The length  92  of the groove  90  and the length  93  subdivide the respective web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  in the longitudinal direction of the sleeve  30  into a secondary section  100  and a main section  102 . The secondary section  100  extends over the length  92  or runs along the groove  90 . The main section  102  extends over the length  93 . The main section  102  therefore also has a length  93  of 14.95 mm. The main section  102  which, in the exemplary embodiment shown, directly adjoins the secondary section  100  is at a distance of 14.4 mm from the second end side  66  of the sleeve  30 . It is also possible for the secondary section  100  of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  to be omitted. Of the webs or a web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 , only the respective main section  102  would therefore be present. At a length of 14.95 mm, a proportion of the diameter, which is 11.8 mm, of the mounting surface  72  of around 1.27 is produced. This proportion still remains favorable for the resulting surface pressure on the side walls  87 . Further advantageous values are produced when the proportion of the length of the main section  102  to the diameter of the first contact surface  72  is between 1 and 1.5, preferably between 1.2 and 1.3. 
         [0082]    As already mentioned, the previous description with regard to the sleeve  30  according to  FIGS. 8 to 12  also applies to the shortened sleeve  30   a  of  FIG. 13 . With regard to the sleeve  30   a , reference is therefore expressly made to this description in order to avoid unnecessary repetitions. Reference numbers which do not occur in  FIG. 13  but have been previously mentioned with regard to  FIGS. 8 to 12  also ensue directly and unambiguously with regard to  FIG. 13 . The sleeve  30   a  has a length of 30 mm in relation to the sleeve  30 . At the transition of the first end side  64  to the contact surface  72 , the sleeve has a hollow  99 . The volume of the sleeve  30   a  is preferably 3.18 cm 3  in total, wherein there can be a deviation of up to 10%, in particular of up to 5%. 
         [0083]    In contrast to the sleeve  30   a  which ends after the first contact surface  72 , in the interior of the sleeve  30  of  FIGS. 8 to 12  the contact surface  72  is adjoined by a transition region  104  and the latter is adjoined by a second contact surface  106 . If the sleeve  30  is produced by a plastics injection molding process, the second contact surface  106  preferably likewise does not have a mold release slope. A hollow  108  which extends over 1 mm in the longitudinal direction of the sleeve  30  is preferably formed between the second contact surface  106  and the first end side  64 . The second contact surface  106  has a length  110  of 10 mm minus the length which is produced for the hollow  108 , if present, as measured from the first end side  64 . At this length  110 , the diameter of the second contact surface  106  is constant and is 12.2 mm. The transition region  104  therefore has a resulting length of approximately 20 mm. The diameter of the transition region  104  lies between both of the first and second contact surfaces  72  and  106 , that is to say, between 11.8 and 12.2 mm, for example 12 mm. In the present exemplary embodiment, the second contact surface  106  adjoins the first contact surface  72  with the interconnection of the transition region  104 . However, the second contact surface  106  can also directly adjoin the first contact surface  72 . In both cases, the second contact surface  106  therefore adjoins the first contact surface  72 . 
         [0084]    It should also be noted that the volume of the sleeve  30  is preferably 5.78 cm 3  overall, wherein there can be a deviation of up to 10%, in particular of up to 5%. 
         [0085]      FIG. 14  shows a pin-shaped bearing device, also referred to below as pin  120 , which is arranged in the longitudinal bore  56 . The pin  120  supports the ball  34 , as a result of which the pin  120  forms a locking device for the securing device  36 , but this will also be discussed. The pin  120  has a length of 18 mm and a diameter of 5.9 mm and is preferably made from steel or plastic. Instead of the circular cross-sectional area, a different cross-sectional area, for example an oval or polygonal cross-sectional area, can also be provided. The pin  120  can taper in the longitudinal direction in a manner going away from a first end side  122 . The tapering can run continuously and/or conically, but also with steps. The profile of the cross-sectional area of the pin  120  has to be adapted to the profile of the cross-sectional area of the longitudinal bore  56  of the shaft  20  such that, after assembly in the longitudinal bore  56 , the pin  120  has a sliding fit and can be displaced over a certain distance. 
         [0086]    An annular groove  124  which has a width of 1.2 mm and a depth from the outer circumference of the pin  120  of 0.7 mm runs at a distance of 1.4 mm from the first end side  122  of the pin  120 . This results in a diameter of the annular groove  124  of 4.5 mm. A collar  125  is therefore produced between the first end side  122  and the annular groove  124 . 
         [0087]    A radially open pocket  126  is formed at a distance of 5.6 mm from the first end side  122 . The pocket  126  has a side surface  128  running transversely with respect to the longitudinal axis of the pin  120 . The side surface  128  is therefore at a distance of 5.6 mm from the first end side  122 . The side surface preferably has a height of 4 mm, as measured from the outer circumference of the pin  120 . That end of the side surface  128  which is remote from the outer circumference of the pin  120  is preferably rounded and has in particular a radius of 1 mm. 
         [0088]    The side surface  128  is adjoined in the pocket  122  by a base surface  130 . The base surface  130  preferably runs parallel to the longitudinal axis of the pin  120  and, owing to the height of the side surface  128 , is at a distance of 4 mm from the outer circumference of the pin  120 . The base surface  130  also ends at a radius of preferably 1 mm, and therefore the base surface  130  is substantially U-shaped, and a ramp  132  which is preferably inclined at an angle of 130° with respect to the longitudinal axis of the pin  120  adjoins the radius at a height of 1.3 mm above the base surface  130 . The ramp  132  points away from the first end side  122 . The ramp  132  points away from the base surface  130  with an increasing height over the base surface  130 . The ramp ends after 3.25 mm, as seen in the longitudinal direction, and merges via a radial step  134  into the outer circumference of the pin  132 . A second end side  136  is formed at the end opposite the first end side  122  of the pin  120 . The two end sides  122  and  136  are preferably of flat design. 
         [0089]      FIGS. 15 to 17  show the cap  32  in detail. The cap  32  preferably has a diameter of 8.2 mm and a length of 3.3 mm. The cap  32  has a flat, substantially round end wall  142 . The end wall  142  can have a central through hole (not shown). The end wall  142  is adjoined by a first section  144  which has a C-shaped cross-sectional form, wherein the outside radius corresponds to that of the end wall  142 . The inside radius of the first section  144  is at least 2.95 mm. The first section  144  is adjoined by a second C-shaped section  146  which has an inside radius of 4.5 mm. The inside length of the first section  144  between the end wall  142  and the second section  146  is 1.4 mm. The inside radius is at least dimensioned in such a manner that the C-shaped section  146  can be clipped onto the annular groove  124 . The two C-shaped sections  144  and  146  result in a radial mouth  147  via which the cap  32  can be latched laterally over the collar  123  of the pin. Two slots  148  running in the axial direction of the cap  32  divide the C-shaped sections  144  and  146 , as a result of which the cap  32  can also be fastened when mounted on the pin  120 . A cap  32  can also be adhesively bonded on the pin  120  or the latter can be insert molded with the cap  32 . Other fastening possibilities are conceivable. 
         [0090]    The cap  32  is preferably colored red or a different color which indicates to a person operating the machine tool  10  that the securing device  36  can be operated via the cap  32 . The cap  32  can also be omitted. In this case, the end side  122  and/or the collar  123  can be provided with a red or other signaling color. 
         [0091]    Alternatively, the first C-shaped section  144  can also be of hollow-cylindrical design without a lateral mouth  147 . The second section  146  with the smaller inside radius would be omitted. The slots  148  could be present or could also be omitted. In this case, the cap  32  is pressed axially onto the region of the collar  123 , wherein, in this case, the annular groove  124  can also be omitted. 
         [0092]    The assembly of the shaft  20 , the cap  32 , the ball  34 , the pin  120  and a spring  150  is now explained with the aid of  FIG. 18 . It is possible to mount the shaft  20  into the receptacle  19  of the drive head  18  before or after this assembly. However, the shaft  20  should preferably be mounted onto the machine tool  10  before the assembly since it is easier to press on. 
         [0093]    For the assembly, the ball  34  is placed into the pocket  126 , in particular onto the base surface  128  of the pin  120 . As a result, the securing device  36  is at least partially preassembled. The spring  150  is inserted into the longitudinal groove  56  of the shaft  20 . However, the spring  150  can also be fastened to the pin  120  beforehand and can be introduced together therewith into the longitudinal bore  56 . The securing device  36  is pushed into the longitudinal bore  56  or shaft  20  counter to the spring force of the spring  150  in such a manner that the ball  34  comes into the region of the first opening  60 . The assembly then has to be oriented in such a manner that the ball  34  protrudes through the opening  60  and bears against the ramp  132 . The pin  120  can then be released. The spring  150  presses here against the pin  120  which moves somewhat out of the bore  56 . The ramp  132  then presses against the ball  34  which, in turn, presses against the opening  60 . As a result, the securing device  36  is held in the shaft  20 . The force of the spring  150  therefore acts in such a manner that the securing device  36  presses in the direction out of the first end  31  of the shaft  20  and that the securing device  36  is held in the shaft  20  by the ball  34  or the blocking device. In the installed state, the force of the spring  150  is 5-20 N, preferably 10 N. In addition to a spring  150 , the use of a magnet which can apply a force to the pin  120  is also conceivable, but the spring  150  is preferred. 
         [0094]    The assembly consisting of shaft  20 , ball  34 , pin  120 , and spring  150  can also be mounted without a cap  32 . If a cap  32  is mounted, which is preferred, said cap is now placed onto the pin  120 . As a result, the pin  120  can no longer be pressed into the bore  56  to an extent such that the ball  34  can rest completely on the base surface  130 . This constitutes a better securing of the securing device  36  against removal. However, it is also possible to place the cap  32  onto the pin  120  after the mounting of the assembly consisting of shaft  20 , ball  34 , pin  120  and spring  150 . 
         [0095]    It is now also clear that the ball  34  is movable radially with respect to the outer circumference of the shaft  20  by means of the ramp  132 , specifically by means of the increasing distance of the ramp  132  from the second end  37  to the first end  31  of the shaft  20 , as a result of which, when the pin is displaced in the shaft  20  from the first end  31  to the second end  37 , the blocking device can move away from the outer circumference. 
         [0096]    The securing device  36  is then fastened in the longitudinal bore  56  emerging from the end side of the first end  31  of the shaft  20  or in a differently designed axial recess which has already been described above. The longitudinal bore  56  preferably extends over the length of the pin  120  in the installed state and additionally over the displacement travel of the pin  120  into the longitudinal bore  56 . As already described, the two cross-sectional areas can also taper. 
         [0097]    In the assembled state, it is also now shown more clearly that the securing device  36  preferably comprises only one ball  34  or other blocking device protruding from one of the groove bases  52  although a plurality of grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  are arranged on the shaft  20 . It is also possible for the pin  120  to be of longer design and to have a plurality of pockets  126  one behind another for balls  24 . If the shaft  20  has a larger diameter, the pockets  126  and balls  34  can be arranged distributed at the same height on the circumference. 
         [0098]    When the roller  24  is mounted onto the shaft  20 , the sleeve  30  is guided by the mounting opening  68  over the first end  31  of the shaft  20 . Instead of the sleeve  30 , it is, of course, also possible for the sleeve  30   a  to be placed onto the shaft  20 . Only the sleeve  30  is mentioned below for the purposes of the description. However, the mounting of the sleeve  30   a  is analogous. The webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  are oriented with respect to the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  in such a manner that each web  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  is aligned with a respective groove  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4 . This is simpler because of the four webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  and grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  which are in each case present than with a smaller number. The sleeve  30  is then pushed further onto the shaft  20 . When the step  98  of the ramp  96  reaches the ball  34 , the step presses the latter against the ramp  132  of the pin  120 . Since the ball  34  is guided in the bore  60 , the ball is pressed radially inward into the longitudinal bore  56 . In the process, the pin  120  is pressed in the axial direction via the force acting on the ramp  132  into the longitudinal bore  56  counter to the spring force of the spring  150 . When the roller  24  or sleeve  30  is pushed further onto the shaft  20 , the ball  34  is pressed via the ramp  96  of the sleeve  30  into the bore  60  until the highest point of the ramp  96  is reached. This is the case in the region of the wall  94 . 
         [0099]    If the roller  24  or sleeve  30  is pushed further onto the shaft  20 , the ball  34  protrudes from the groove base  52 . The ball  34  protrudes behind the wall  94  into the groove  90 , which is shown in  FIG. 19 . A section which can be referred to as the retaining section  152  of the ball  34  comes into contact with the wall  94 . The retaining section  152  here has a radial excess length with respect to the groove base  53  or with respect to an outer surface of the shaft  20 , which outer surface is adjacent to the ball  34 . It is therefore clear that the ball  34  or blocking device has a radially protruding retaining section  152  for the sleeve  30  or device which is mounted on the shaft  20  and can be guided through the hollow receiving region  38  when the sleeve  30  is mounted. 
         [0100]    In addition to the ball  34  which comes into contact with the wall  94 , the steps  98  of the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  also come into contact with the groove ends  53  of the grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4 . The sleeve  30  is clamped in the axial direction on the shaft  20  between the ball  34  or the retaining section  152  thereof and a groove end  53  of at least one groove  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4 . The sleeve  30  is now also locked on the shaft  20 , wherein the locking has taken place automatically. The automatic locking is achieved by the ball  34  being pressed radially outward with a force acting transversely with respect to the longitudinal bore  56  by the ramp  132  of the pin  120 , which is acted upon by the spring  150 . The ball  34  is thus held in the locked state by means of an elastic force. If it is desired to pull the sleeve  30  from the shaft  20 , the wall  94  presses against the retaining section  152  or the ball  34 . The ball  34  is pressed here against the edge of the bore  56  by a section  154  remote from the retaining section  152 . However, the ball  34  cannot be deflected inward such that the locking comes about. 
         [0101]    In the mounted state, the first contact surface  72  of the sleeve  30  rests on the first supporting region  46  of the shaft  20 , and the second contact surface  106  of the shaft rests on the second supporting region  48  of the shaft  20 . In the case of the sleeve  30   a , only the contact surface  72  rests on the first supporting region  46  of the shaft  20 . The grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  of the shaft  20  receive the webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4  of the sleeve  30 . If the shaft  20  is driven, the side surfaces  54  of the four grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  press against the side walls  87  of the four webs  39 . 1 ,  39 . 2 ,  39 . 3 ,  39 . 4 . As a result, a relatively high torque can be transmitted. The grooves  50 . 1 ,  50 . 2 ,  50 . 3 ,  50 . 4  constitute torque-transmitting sections of the shaft  20 , which sections can be arranged in the hollow receiving region  38  of the sleeve  30 . 
         [0102]    An advantageous aspect is therefore that a blocking device, for example in the form of the ball  34 , is arranged on the securing device  36 , said blocking device, in a locked state, blocking the sleeve  30  or  30   a  against removal from the shaft  20  and, in an unlocked state, enabling removal of the sleeve  30  or  30   a  for the shaft  20 . It is also advantageous that a locking device which is preferably designed as a pin  120  is arranged on the securing device  36 , with which locking device the ball  34  can be unlocked or with which the ball  34  can be unlocked and can be locked, wherein the pin  120  is arranged at the first end of the shaft  20 . 
         [0103]    It is also apparent from the described mounting that the pin  120  or the blocking device can be unlocked manually and is automatically locked, but also, in the locked state, permits the mounting of a sleeve  30  or  30   a  or of a tubular device. 
         [0104]    The removal is clear from  FIG. 20 . In this connection, the securing device  36  is transferred from the locked into the unlocked state by axial pressing of the cap  32  against the shaft  20 . The pin  120  is pressed into the longitudinal bore  56  counter to the spring force of the spring  150 . In the process, the ramp  132  of the pin  120  is also displaced. As a result, the ball  34  has space radially inward. If the roller  24  or the sleeve  30  or  30   a  is then pulled from the shaft  20 , the ball  34  of the wall  94  and of the ramp  96  can be deflected. The roller  24  can then be completely removed from the shaft  20 . An advantageous aspect of the removal is that, at least during the removal of a roller  24  or sleeve  30  or  30   a  mounted on the shaft  20 , the securing device  36  remains on the shaft  20 . However, owing to the axial displacement travel of the pin  120  arising because of the cap  32 , the ball  34  cannot penetrate into the longitudinal bore  56  to such an extent that an unintentional removal of the pin  120  or of the securing device  36  is possible. 
         [0105]    It is clear from the explained exemplary embodiment that the securing device  36  takes up a locking position in the locked state and an unlocking position in the unlocked state and that the locking position and the unlocking position are spaced apart radially on the shaft  20 . This is achieved by the ball  34  being kept in the position thereof in the locked state and being able to be deflected inward in the unlocked state. 
         [0106]    Alternatively, it is also possible for the pin  120  to have an external thread and for the longitudinal bore  56  to have a matching internal thread. If the pin is screwed into the shaft  20 , the ball  34  can be deflected inward. As a result, the ball  34  is unlocked manually. 
         [0107]    A sleeve  30  or  30   a  can then be mounted. The pin  120  can then be unscrewed out of the shaft  20  to an extent such that the ball  34  is pressed radially outward via the ramp  132  until the ball  34  clamps the sleeve  30  or  30   a . As a result, the sleeve  30  or  30   a  is locked manually. The pin  120  here is preferably rotated by less than 360°, which reduces the time needed for the locking and unlocking. The pin  120  is preferably rotated by approximately 180°. As a result, the time needed for the locking and unlocking is reduced, wherein the locking or unlocking operation is imparted to an operator sufficiently intuitively. 
         [0108]    It is also conceivable for a modified pin to be mounted rotatably in the longitudinal bore  56  and to be pressed in one direction via a torsion spring. A pocket then has a base which has a change in distance from the center axis. As a result, a rotating movement of the pin can bring about locking and unlocking. 
         [0109]    It is therefore apparent from the described embodiments that a securing device can be transferred from the locked into the unlocked state by axial pressing of an actuating element against the shaft or rotation of the actuating element about a longitudinal axis of the shaft. 
         [0110]    It is likewise apparent that a securing device takes up a locking position in the locked state and an unlocking position in the unlocked state, and that the locking position and the unlocking position can be spaced apart radially and/or tangentially and/or axially on the shaft.