PAIR OF CONNECTABLE PORTIONS FOR CONNECTING A TRANSMISSION SHAFT AND A ROLLER

Abstract

A transmission shaft and a roller comprising a pair of connectable portions (M, F) for connecting a transmission shaft (5, 8) and a roller (4, 7) to be driven by torque exerted through the transmission shaft (5, 8). The pair of connectable portions (M, F) comprise a male portion (M) provided on one of the transmission shaft (5, 8) and roller (4, 7) and a complementary female portion (F) provided on the other of the roller (4, 7) and transmission shaft (5, 8). The male portion (M) has a longitudinal axis of rotation (X) and tapers inwardly from a proximal end to a distal end. The male portion (M) has a non-circular cross section.

Claims

1. A transmission shaft and a roller comprising a pair of connectable portions for connecting the transmission shaft and the roller to be driven by torque exerted through the transmission shaft, the pair of connectable portions comprising a male portion provided on one of the transmission shaft and roller and a complementary female portion provided on the other of the roller and transmission shaft, the male portion having a longitudinal axis of rotation and tapering inwardly from a proximal end to a distal end by an angle of between 2.5 and 25 degrees, wherein the male portion has a non-circular cross section.

2. A transmission shaft and a roller according to claim 1, wherein the male portion is provided on the transmission shaft and the female portion is provided in the roller.

3. A transmission shaft and a roller according to claim 1, wherein the cross-sectional shape of the male portion remains constant along at least 50% of the distance from the proximal end to the distal end.

4. A transmission shaft and a roller according to claim 1, wherein the male portion has an order of rotational symmetry from 1 to 20.

5. A transmission shaft and a roller according to claim 1, wherein the male portion has an elliptical or polygonal cross section.

6. A transmission shaft and a roller according to claim 1, wherein the male portion has a polygonal cross section and wherein the vertices are curved.

7. A transmission shaft and a roller according to claim 1, wherein the male portion has a rectangular cross section, for example a square cross section.

8. A roller set comprising a transmission shaft and a roller according to claim 1 wherein the transmission shaft engages a first end of the roller and further comprising a second shaft for engaging a second end of the roller.

9. A roller set according to claim 8, wherein the roller and the second shaft comprise a second pair of connectable portions having a second male portion located on one of the roller and the second shaft and a complementary second female portion located on the other of the second shaft and the roller, wherein the second male portion has a non-circular cross section.

10. A roller set according to claim 8, wherein the roller and the second shaft comprise a second pair of connectable portions having a second male portion located on one of the roller and the second shaft and a complementary second female portion located on the other of the second shaft and the roller, wherein the second male portion has a circular cross section.

11. A pair of roller sets for passing a sheet material therebetween, the first roller set according to claim 8.

12. A pair of roller sets according to claim 11, wherein the second roller set comprises a pair of connectable portions according to claim 1.

13. A pair of roller sets according to claim 12, wherein the pair of connectable portions of the second roller set comprises a male portion with a different cross-sectional shape to that of the male portion of the pair of connectable portions of the first roller set.

14. A pair of roller sets according to claim 11, wherein the pair of roller sets is arranged to process a cast leaf tobacco sheet between the roller of the first roller set and the roller of the second roller set.

15. A method of forming a connection between a transmission shaft and a roller to be driven by torque exerted through the transmission shaft, the method comprising: axially aligning a male portion provided on one of the transmission shaft and roller with a complementary female portion provided on the other of the roller and transmission shaft; moving the transmission shaft and roller relatively toward one another axially, such that the male portion engages within the complementary female portion; wherein the male portion has a longitudinal axis of rotation, tapers inwardly from a proximal end to a distal end by an angle of between 2.5 and 25 degrees and has a non-circular cross section.

16. A method of driving the rotation of a roller, the method comprising transmitting torque from a transmission shaft to the roller by transmitting the torque between a male portion provided on one of the transmission shaft and roller and a corresponding female portion provided on the other of the roller and transmission shaft, wherein the male portion has a longitudinal axis of rotation, tapers inwardly from a proximal end to a distal end by an angle of between 2.5 and 25 degrees and has a non-circular cross section.

Description

[0041] The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

[0042] FIG. 1 is a schematic cross-sectional view of a roller apparatus comprising a pair of connectable portions for connecting a roller and a transmission shaft according to an embodiment of the invention;

[0043] FIG. 2 is a close-up view of the area inside box A in FIG. 1;

[0044] FIG. 3 is a partial perspective view of the end of a roller shown in FIG. 1;

[0045] FIG. 4 is a perspective view of the inner surface of the female portion in the end of the roller shown in FIG. 2;

[0046] FIG. 5 is a schematic side view of the inner surface of the female portion shown in FIG. 4.

[0047] Referring now to FIGS. 1 and 2 there is shown a roller apparatus 1 comprising first and second roller sets 2, 3 and a roller apparatus body B. The first roller set 2 comprises a first roller 4, a first transmission shaft 5 and a first support shaft 6. The second roller set 3 comprises a second roller 7, a second transmission shaft 8 and a second support shaft 9. The first and second rollers 4, 7 each extend from a respective first end 40, 70 to a respective second end 41, 71, and each include an outer, work surface 42, 72.

[0048] The first end 40 of the first roller 4 is connected to the first transmission shaft 5 by a first pair of connectable portions C.sub.1. The second end 41 of the first roller 4 is connected to the first support shaft 6 by a second pair of connectable portions C.sub.2. The first end 70 of the second roller 7 is connected to the second transmission 8 shaft by a third pair of connectable portions C.sub.3. The second end 71 of the second roller 7 is connected to the second support shaft 9 by a fourth pair of connectable portions C.sub.4.

[0049] Each transmission shaft 5, 8 and each support shaft 6, 9 are supported by and rotatably attached to the roller apparatus body B, for example by bearings. The transmission shafts 5, 8 and support shafts 6, 9 are formed from metal, for example stainless steel, in this embodiment. The rollers 4, 7 each comprise a central portion surrounded by a peripheral portion. The central portion comprises the first and second ends 40, 70, 41, 71 and is formed from metal, for example stainless steel, in this embodiment.

[0050] The first pair of connectable portions C.sub.1 comprises a male portion M provided on the first transmission shaft 5 and a female portion F provided in the first end 40 of the first roller 4.

[0051] As shown in greater detail in FIGS. 3, 4 and 5, the female portion F comprises a recess in the first end 40 of the first roller 4. The female portion F has a frusto-pyramidal shape with a longitudinal axis if rotation X. The frusto-pyramid tapers inwardly from a base BA at the first end 40 of the first roller 4 towards a peak P. The frusto-pyramid tapers inwardly in the direction from the first end 40 towards the second end 41 of the first roller 4. The frusto-pyramid tapers from its base BA towards its peak P at an angle . In this embodiment angle is greater than 2.5 degrees (i.e. the frusto-pyramid tapers inwardly in the direction from the first end 40 towards the second end 41 of the first roller 4 by an included angle of greater than 5 degrees). However, in embodiments angle may be greater than 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 degrees. In embodiments, angle may be between 2.5 and 70 degrees, for example between 3, 4, 5, 6, 7, 8, 9 or 10 degrees and 65, 60, 55, 50, 45, 40, 35, 30, 25, 20 or 15 degrees. In embodiments, the frusto-pyramid may taper inwardly in the direction from the first end 40 towards the second end 41 of the first roller 4 by an included angle (e.g. symmetrical about the longitudinal axis of rotation X) of greater than 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 degrees. In embodiments, the frusto-pyramid may taper inwardly in the direction from the first end 40 towards the second end 41 of the first roller 4 by an included angle (e.g. symmetrical about the longitudinal axis of rotation X) of between 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25 or 30 degrees and 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40 or 35 degrees.

[0052] The frusto-pyramid of the female portion F has a length L between the base BA and the peak P. The frusto-pyramid of the female portion F has a square cross section in this embodiment (i.e. the polyhedral base of the frusto-pyramid is a square), in which the vertices V of the square are curved. The base BA has a maximum diameter d, which extends between opposed vertices V of the square cross section, in this embodiment. A central bore CB extends from the peak P of the frusto-pyramid towards the second end 41 of the first roller 4. The central bore CB is threaded along at least part of its length.

[0053] The first transmission shaft 5 is elongate and extends from a first end to a second end. The male portion M is provided on the first transmission shaft 5, on the first end thereof, as shown in FIGS. 1 and 2. The male portion M comprises a projection which is sized and shaped to correspond to and engagingly cooperate with the female portion F at the first end 40 of the first roller 4, in use. As will be appreciated by one skilled in the art, the description of the shape of the female portion F is applicable also to the shape of the male portion M, which comprises a substantially negative image of the female portion F. A central bore CB extends through the centre of the male portion M along its longitudinal axis of rotation, which corresponds to the longitudinal axis of rotation X of the female portion F.

[0054] A central bore CB extends through and along the entire length of the first transmission shaft 5, from the first end to the second end thereof. The central bore CB is threaded along at least part of its length.

[0055] The second, third and fourth pair of connectable portions C.sub.2, C.sub.3, C.sub.4 comprise male portions M and female portions F which may optionally be the same as those of the first pair of connectable portions C.sub.1 described above, and will not be described herein further.

[0056] Prior to use, the first transmission shaft 5 is rotatably retained in and supported by the roller apparatus body B prior to mounting of the first roller 4 thereon. Mounting of the first roller 4 comprises the first roller 4 being connected to the first transmission shaft 5 by the first pair of connectable portions C.sub.1. The female portion F in the first end 40 of the first roller 4 is lined up with the male portion M provided on the first transmission shaft 5. The first roller 4 is then moved axially onto the first transmission shaft 5 such that the male portion M is received within the female portion F. In this way, the first roller 4 is at least partially connected to the first transmission shaft 5 by friction fit.

[0057] The first transmission shaft 5 and the first roller 4 are then attached by a central screw CS, inserted through the second end of the first transmission shaft 5 and threadedly engaging the central bores CB of both the first transmission shaft 5 and the first end 40 of the first roller 4. Tightening of the central screw CS causes the male portion M and female portion F to axially align, even if they were at least partially misaligned prior to engagement of the central screw CS. Furthermore, tightening of the central screw CS causes compression of the outer surfaces of the male portion M against the inner surfaces of the female portion F. Advantageously, the configuration of the first pair of connectable portions C.sub.1 according to the invention ensures the efficient transfer of torque from the first transmission shaft 5 to the first roller 4, in use, relies to a lesser extent on compression of the outer surfaces of the male portion M against the inner surfaces of the female portion F than is the case with a male portion M having a circular cross section. Accordingly, the central screw SC need be tightened to a relatively lesser extent than would be the case were the male portion M to have a circular cross section. Hence, the first pair of connectable portions C.sub.1 can be disconnected (and hence the first roller 4 unmounted) in relatively less time than would be the case if the male portion M had a circular cross section.

[0058] Furthermore, provision of non-circular cross-section male portion M according to the invention reduces the wear on the pair of connectable portions C.sub.1. When the male portion M and female portion F are fully connected the portions M, F are restricted from relative rotation. Accordingly, wear between the male portion M and female portion F is relatively reduced compared to a configuration in which slip may occur even when the portions M, F are fully connected.

[0059] The first support shaft 6 is then axially slid into position in the roller apparatus body B. Splines extending along at least part of the length of the first support shaft 6 are engaged with cooperating recesses in the roller apparatus body B. A male portion M at a first end of the first support shaft 6 is then axially slid into engagement with a cooperating female portion F in the second end 41 of the first roller 4, thereby forming a second pair of connectable portions C.sub.2. The first support shaft 6 is then attached to the first roller 4 by a central screw CS, threadedly engaged through a central bore CB through and along the length of the first support shaft 6 and a central bore CB into the second end 41 of the first roller 4.

[0060] In use, the first transmission shaft 5 is caused to rotate by a motor or other prime mover (not shown) connected thereto. The torque from the first transmission shaft 5 is transmitted to the first roller 4 through the first pair of connectable portions C.sub.1, thereby causing the first roller 4 to rotate. The first support shaft 6 rotates freely within the roller apparatus body B, thereby supporting the second end 41 of the first roller 4. Torque is transmitted from the first transmission shaft 5 to the first roller 4 in part due to friction between the outer surfaces of the male portion M and the inner surfaces of the female portion F of the first pair of connectable portions C.sub.1.

[0061] The second roller 7 is mounted in the second roller set 3 prior to use in the same manner as described above in respect of the first roller 4 in the first roller set 2. The second transmission shaft 8 is also caused to rotate, in use, by a motor or other prime mover (not shown). Articles, for example a tobacco cast leaf sheet, can then be passed between the nip between the first and second rollers 4, 7. In this way, an article, such as tobacco cast leaf sheet, is processed between the working surfaces 42, 72 of the rollers 4, 7.

[0062] Removing the first roller 4 comprises: [0063] unscrewing the central screw CS from the central bore CB of the second end 41 of the first roller 4 and the first support shaft 6; [0064] removing the first support shaft 6 from the roller apparatus body B by axially sliding it out therefrom along its splined inter-engagement, in a direction away from the first roller 4, thereby disengaging the second pair of connectable portions C.sub.2 between the second end 41 of the first roller 4 and the first support shaft 6; [0065] unscrewing the central screw CS from the central bore CB of the first transmission shaft 5; and [0066] moving the first roller 4 away from the first transmission shaft 5, thereby disengaging the first pair of connectable portions C.sub.1 between the first end 40 of the first roller 4 and the first transmission shaft 5.

[0067] The removed first roller 4 may subsequently be replaced or repaired.

[0068] While the pairs of connectable portions C.sub.1, C.sub.2, C.sub.3, C.sub.4 have been described in the context of two roller sets 2, 3, it would be apparent to the skilled person that this description would apply mutatis mutandis to roller apparatus comprising any number of roller sets 2, 3 or, indeed, rollers 4, 7.

[0069] It will be appreciated that although the second, third and fourth pairs of connectable portions C.sub.2, C.sub.3, C.sub.4 are described as being the same as the first pair of connectable portions C.sub.1 this need not be the case and, instead, one or more of the second, third and fourth pairs of connectable portions C.sub.2, C.sub.3, C.sub.4 may comprise a female portion F having a recess with a cross-section of different shape to the female portion F of the first pair of connectable portions C.sub.1. Where the female portion F of one or more of the second, third and fourth pairs of connectable portions C.sub.2, C.sub.3, C.sub.4 has a recess with a cross section of different shape to the female portion F of the first pair of connectable portions C.sub.1, the male portion M of the corresponding second, third and/or fourth pair of connectable portions C.sub.2, C.sub.3, C.sub.4 has a complementary shape to that of the female portion F of the relevant second, third and/or fourth pair of connectable portions C.sub.2, C.sub.3, C.sub.4. The cross-sectional shapes of the male and female portions M, F of the first pair of connectable portions C.sub.1 may differ from the cross-sectional shapes of the male and female portions M, F of the second pair of connectable portions C.sub.2. Advantageously, installation of the first roller 4 in its desired orientation (for example with respect to the second roller 7) may thereby be ensured. Accordingly, installation in the desired orientation of the roller 4 may be achieved relatively more rapidly and readily than may be case when installing a first roller 4 in which the first and second pair of connectable portions C.sub.1, C.sub.2 each have male portions M having the same cross-sectional shape. Relatively more rapid installation of the first roller 4 results in relatively reduced down-time of the roller apparatus 1, and thereby reduces the expense of using the roller apparatus 1.

[0070] While the rollers 4, 7 are described as each comprising a central portion and a peripheral portion, this is not essential to the invention. While central screws CS have been described, they are not essential to the present invention. While central bores CB have been described, they are not essential to the present invention. While support shafts 6, 9 have been described, they are not essential to the present invention.

[0071] The schematic drawings are not necessarily to scale and are presented for purposes of illustration and not limitation. The drawings depict one or more aspects described in this disclosure. However, it will be understood that other aspects not depicted in the drawings fall within the scope of this disclosure.