# Patent

## Title
Spindle

## Abstract

In one embodiment, a roll spindle comprises two roll supports and a differential.

## Background
BACKGROUND OF THE INVENTION
Spindles are used to wind and unwind rolls. A drive may drive the spindle for winding and unwinding the rolls for transporting a roll material through a processing system. In many instances, the processing system is provided with the drive for rotating the spindle. A known example of a roll processing system is a printer. It can be efficient to use a single spindle for rotating multiple rolls.



BRIEF DESCRIPTION OF THE DRAWINGS
For the purpose of illustration, certain embodiments of the present invention will now be described with reference to the accompanying diagrammatic drawings, in which:
FIG. 1 shows a diagram of an embodiment of a spindle that is mounted on a roll processing apparatus wherein the spindle supports two rolls;
FIG. 2 shows a diagram of an embodiment of a spindle that is mounted on a roll processing apparatus wherein the spindle supports a single roll;
FIG. 3 shows a cross sectional front view of an embodiment of a spindle;
FIG. 4 shows a detailed cross sectional front view of an embodiment of a differential and a transmission shaft of a spindle;
FIG. 5 shows an exploded perspective view of an embodiment of the differential shown in FIG. 4;
FIG. 6A shows a cross sectional perspective view of an embodiment of a spindle end portion with a blocking arrangement in a blocking position;
FIG. 6B shows a cross sectional side view of the embodiment of the spindle end portion and blocking arrangement of FIG. 6A in a blocking position;
FIG. 6C shows a cross sectional side view of the embodiment of the spindle end portion and blocking arrangement of FIGS. 6A and 6B in a released position;
FIG. 7 shows a detailed cross sectional perspective view of another embodiment of a differential in a spindle;
FIG. 8 shows a flow chart of an embodiment of a method of processing rolls.



DETAILED DESCRIPTION
In the following detailed description, reference is made to the accompanying drawings. The embodiments in the description and drawings should be considered illustrative and are not to be considered as limiting to the specific embodiment or element described. Multiple embodiments may be derived from the following description and/or drawings through modification, combination or variation of certain elements. Furthermore, it may be understood that other embodiments or elements that are not literally disclosed may be derived from the description and drawings by a person skilled in the art.
FIG. 1 shows a system 1 comprising a spindle 2. The spindle 2 is arranged to support one or multiple rolls 3. In the drawing, the spindle. 2 supports two rolls 3, 4. The system 1 comprises a drive 5 for driving the spindle 2. The drive 5 engages the spindle at at least one of its end portions 6, 7. The drive 5 is arranged to rotate the spindle 2 for winding and/or unwinding the rolls 3, 4, about an axis of rotation C. Winding and/or unwinding the rolls 3, 4 causes the roll material to advance through the system 1. In one embodiment, the system 1 comprises a printing system, for example a large format printing system. The rolls 3, 4 may comprise rolls of print media
The spindle 2 is arranged to simultaneously rotate two rolls 3, 4. In an embodiment, the spindle 2 comprises two support tubes 8, 9 extending along the axis C of rotation of the spindle 2. In other embodiments, the spindle 2 may comprise other types of supports for engaging and supporting the rolls 3, 4, such as feet or rings that rotate around said axis of rotation C.
The spindle 2 comprises a differential 10. The differential 10 may extend approximately in the middle of the spindle 2. The differential 10 has two outputs 15, 16 and one input 17, as shown in FIG. 3. Each differential output 15, 16 is connected to a support tube 8, 9 to rotate the respective support tube 8, 9. Each tube 8, 9 may support a respective roll 3, 4.
The spindle 2 comprises a drive transmission 11A for transmitting a drive movement from the drive 5 to the differential 10. In use, the drive transmission 11A engages the drive 5. The differential 10 and the drive transmission 11A are indicated in dashed lines. In the shown embodiment, the drive transmission 11A comprises a transmission shaft 11 within one of the tubes 8, extending from an end portion 6 of the spindle 2 to the differential 10. The drive transmission 11A may further comprise a gear 13 for transmitting movement from the external drive 5 to the transmission shaft 11, as shown in FIG. 3.
In use, the drive 5 rotates the drive transmission 11A. The drive transmission 11A rotates the differential 10. The differential 10 equally distributes the incoming torque to each of the tubes 8, 9, so that both rolls 3, 4 may simultaneously wind or unwind at equal media tension, independent of whether the diameters of the rolls 3, 4 are equal or not, or of whether one of the rolls 3, 4 has ended. In an embodiment, approximately half of the drive torque is transmitted to a first support tube 8, and approximately half of the drive torque is transmitted to a second support tube 9. Equalizing the distribution may maintain the roll material tension of both rolls 3, 4, even when they are of different diameters. Equalizing the output torque may reduce roll material wrinkle, even when multiple rolls 3, 4 are used.
In an embodiment, the outer dimension D1 of the differential is equal to or less than the outer dimension D2 of the support tubes 8, 9, as shown in FIGS. 1 and 3. If the differential does not protrude from the outer dimension D2 of the support tubes 8, 9 this allows that a roll 3 slides over the differential 10 with little or no disruption, allowing relatively easy mounting of one or more rolls 3, 4.
FIG. 2 shows an embodiment of the system 1 with the same spindle 2 as in FIG. 1, except for the fact that only one roll 12 is mounted onto the spindle 2. The roll 12 extends, and is supported by, both support tubes 8, 9. The roll 12 of FIG. 2 is longer than approximately half of the spindle 2. The roll 12 is longer than one support tube 8 or 9. The spindle 2 may have only one rotation speed along its full length, as with most conventional spindles 2, to properly rotate one roll 12. Also when the spindle 2 supports a single roll that is shorter than half of the spindle 2, a single rotation speed may be applied.
In an embodiment, the outer surface of the spindle 2 is free of protrusions, at least between its two end portions 6, 7, for being able to support one roll (FIG. 2) or more rolls (FIG. 1) along its full length, without having to assemble or disassemble parts of the spindle 2. For example, the differential 10 may have approximately the same outer diameter as the tubes 8, 9, or the differential 10 may have a smaller diameter than the tubes 8, 9.
FIG. 3 shows a more detailed, cross sectional view of an embodiment of the spindle 2. Note that for means of illustration, mounted rolls 3, 4 are illustrated in dashed lines. One end portion 6 of the spindle 2 comprises a drive engagement portion so as to receive a drive movement from an external drive 5. The drive engagement portion may comprise a gear 13. The gear 13 is connected to the transmission shaft 11. The transmission shaft 11 extends from the gear 13 to the differential 10.
The two support tubes 8, 9 may be referred to as a first and a second support tube 8, 9, respectively. The first support tube 8 is supported by a bearing 14 at one end and by a first differential output 15 at the other end. The bearing 14 is mounted onto the transmission shaft 11. The bearing 14 is arranged to allow rotation of the first tube 8 with respect to the transmission shaft 11.
The second support tube 9 is supported by a second differential output 16 at one end and the other end may form the respective end portion 7 of the spindle. Said end portion 7 of both the spindle 2 and the second support tube 7 is arranged to engage a spindle support of the system 1, opposite to the system drive 5.
FIG. 4 shows an embodiment of the differential 10 and a part of the transmission shaft 11 in cross sectional front view. FIG. 5 shows an exploded view of an embodiment of the differential 10. As can be seen from FIGS. 4 and 5, the differential 10 may comprise a ball differential. The differential 10 comprises a differential input 17 and two outputs 15, 16. The differential input 17 is connected to the transmission shaft 11. In use the differential input 17 is rotated. The differential 10 further comprises a transmission portion 18A for transmitting the rotation of the input 17 to the outputs 15, 16.
In the shown embodiment, the transmission portion 18A comprises a ball bearing. In an embodiment, the ball bearing comprises balls 18 and a wheel 19 containing ball bearing cups 20. The balls 18 sit in the cups 20. The surfaces of the balls 18 extend outside of the wheel 19 on both sides of the wheel 19 for engaging the respective differential outputs 15, 16. In the shown embodiments, the outputs 15, 16 are provided with washers 23 that engage the balls 18. The washers 23 may be fitted in the outputs 15, 16. To rotate with respect to the differential input 17 and the transmission shaft 11 the outputs 15, 16 may be supported by further bearings 22, for example mounted on the differential input 17 or the transmission shaft 11.
The differential outputs 15, 16 may be pressed against the transmission portion 18A by a resilient element such as a helical spring 21 so as to have enough friction between the outputs 15, 16 and the transmission portion, for example to prevent slippage. In the shown embodiment, the spring 21 may prevent slippage between the outputs 15, 16 and the balls 18. The spring 21 may be biased against a foot 24 of the differential input 17. Further bearings may be provided between the spring 21 and the respective output 16 to allow rotation of the spring 21 with respect to the output 16. Further parts of the differential 10 may include seal rings 25, further washers and/or fittings, as can be seen from FIG. 5.
In a situation where two rolls 3, 4 are properly mounted on the respective tubes 8, 9, and both tubes 8, 9 undergo a torque related to winding or unwinding the rolls 3, 4, both the outputs 15, 16 will be driven by the differential input 17 through the balls 18. The balls 18 may adjust the rotational speed of the outputs 15, 16 with respect to each other so that both outputs 15, 16 undergo an equal torque.
In an embodiment of a system for winding or unwinding media from media rolls, a torque on each roll is dependent of the tension in the unwound part of the media. In such embodiment, the torque on the output 15, 16 may be a function of the media tension and vice versa. Since the torques of the outputs 15, 16 are in inherently equal due to the characteristics of the differential 10, the tension in the media is equal for both rolls 3, 4 when rotating the spindle 2. The rotational speed of the two tubes 8, 9 that support rolls 3, 4 of different diameters is automatically adjusted, to the end of providing an equal linear media advance speed of the media of both rolls 3, 4.
FIG. 6A shows a detailed, partly cross sectional, perspective view of an embodiment of the spindle 2 near the first end portion 6. The first end portion 6 comprises a support portion 26 that in use is supported by a spindle support of the system 1. The first end portion 26 comprises a gear 13 that in use is engaged by the system drive 5. The gear 13 is connected to the transmission shaft 11. The support tube 8 is supported by bearings 14 that are supported by the transmission shaft 11.
The embodiment shown in FIG. 6A comprises a blocking arrangement 27. The blocking arrangement 27 is arranged to block the support tubes 8, 9 with respect to each other so that the surface of the spindle 2 has a single rotational speed when rotated by the drive 5. This may be advantageous when mounting rolls 3, 4 onto the spindle 2, or when mounting and rotating just one roll 12 (FIG. 2). It may allow to continue processing one roll 3 when the other one 4 of the two mounted rolls 3, 4 has ended.
The blocking arrangement 27 may be arranged to block one of the support tubes 8, 9 with respect to the drive transmission 11A. In the shown embodiment, the blocking arrangement 27 is arranged to block the first support tube 8 with respect to the transmission shaft 11. This blocks the balls 18 with respect to the respective outputs 15, and the friction between the balls 18 and the second output 16 prevents the second output 16 from rotating with respect to the first output 15. Since both outputs 15, 16 are blocked with respect to each other, both tubes 8, 9 are also blocked with respect to each other.
In the shown embodiment, the blocking arrangement 27 extends near and/or in the end portion 6 of the spindle 2. The blocking arrangement 27 may comprise a latch 28. In the shown embodiment, the latch 28 is connected to the support tube 8, and is arranged to be moved between a blocking position and a released position. In the shown embodiment, the latch 28 is connected to the support tube 8 by a hinge 30, for hinging with respect to the support tube 8. The latch 28 can be actuated near the end portion 6, so that the spindle 2 can be blocked even when rolls 3, 4 are mounted.
In a blocking position, the latch 28 engages the drive transmission 11A, as can be seen from FIG. 6B. In a released position the latch 28 releases the drive transmission 11A, as can be seen from FIG. 6C. In an embodiment, the blocking arrangement 27 extends within the outside dimensions of the support tubes 8, 9.
The latch 28 may lock and unlock, respectively, the support tube 8 with respect to the drive transmission 11A. The drive transmission 11A may comprise one or more notches or slots 29 for receiving the latch 28 in a blocking position. In the shown embodiment, the slots 29 or notches are provided around the transmission shaft 11 to allow the latch 28 to block in multiple positions of the latch 28 with respect to transmission shaft 11. Furthermore the latch 28 is arranged so that it does not extend outside of the circumference of the tube 8 in both a blocking and a released position, as can be seen from FIGS. 6B and 6C. This allows for usage of substantially the full length of the spindle 2.
In FIG. 7 another embodiment of a differential 10A is shown. The transmission portion 183 may comprise a wheel 31 connected to the differential input 17. The wheel 31 comprises flanges 32, between which gear couples 33 are provided. The gear couples 33 comprise two inter-engaging gears 34, 35. When the wheel 31 rotates the gear couples 33 rotate together with the wheel 31 around the rotation axis C of the spindle 2, while each gear 34, 35 may rotate around its own axle 36. The gears 34, 35 inter-engage. Each of the gears 34, 35 may engage a respective toothed inner part of the respective output 15, 16 so that the outputs are rotated with respect to each other when the gears 34, 35 rotate round their own axles 36.
In further embodiments other types of differentials or similar actuators may be suitable. For example such differentials may comprise an electrical, a mechanical, or a magnetic transmission portion, or any other transmission portion that equally distributes an incoming torque over multiple outputs 15, 16. The differential may comprise magnetic gears, and/or friction gears and/or other suitable transmission mechanisms for distributing an input torque over multiple outputs 15, 16. Also, different embodiments of drive transmissions 11A or blocking arrangements 27 are suitable. For example, the drive transmission 11A may comprise a servo-control, or electrical transmission. For example, the blocking arrangement 27 may comprise an electrically controlled, and/or servo-controlled mechanism.
FIG. 8 shows a flow chart of an embodiment of a method of processing rolls 3, 4, 12. In a first step 100, the spindle 2 is blocked by actuating the blocking arrangement 27. The support tubes 8, 9 may be blocked from movement with respect to each other. In an embodiment, the support tubes 8, 9 are blocked with respect to each other by blocking one support tube 8 with respect to the drive transmission 11A near the respective end portion 6.
In a next step 110, the rolls 3, 4 may be mounted onto the respective support tubes 8, 9. A relatively easy mounting of the rolls 3, 4 may be facilitated by blocking rotation of the tubes 8, 9 with respect to each other, as done in step 100. The rolls 3, 4 may be slit over the spindle 2 until both are in a correct position on the respective support tubes 8, 9. The rolls 3, 4 may be slit over one end portion 6 or 7. For example, one roll 3 or 4 is slit over the differential 10.
In a further step 120, a grip arrangement may be actuated for gripping the rolls 3, 4, to prevent slipping of the rolls 3, 4 with respect to the tubes 8, 9. In one embodiment, the actuation mechanism of such grip arrangement may extend through the differential 10 to be able to centrally actuate the grip arrangement in both tubes. 8, 9
In a next step 130, the spindle 2 with the rolls 3, 4 is mounted onto the system 1. The system 1 may be provided with spindle supports. In a supported condition the drive transmission 11A of the spindle 2 may engage the system drive 5. In an embodiment, the drive 5 of the system 1 engages a gear 13 of the drive transmission 11A of the spindle 2. In a further step 140, the spindle 2 is unblocked so that the support tubes 8, 9 are allowed to rotate with respect to each other.
In a further step 150, the spindle 2 is rotated. In an embodiment, the drive transmission 11A is driven, which in turn drives the differential 10. The differential 10 simultaneously drives both support tubes 8, 9 so that each support tube 8, 9 undergoes an equal torque, as indicated by step 160.
While driving the support tubes 8, 9 the rolls 3, 4 are processed, as indicated by step 170. In one embodiment, the media from the rolls is advanced and printed. Unwound roll material may be finished, cut, stacked, folded, etc. After having at least partly processed the rolls 3, 4, the left over parts may be removed from the spindle 2. Therefore, the spindle 2 may be blocked again, as indicated by step 180, to readily remove the rolls 3, 4 from the spindle 2. Steps 100-170 may be repeated.
In an embodiment, the rolls 3, 4 are mounted onto the pre-assembled spindle 2, so that each roll is supported by a separate support tube 8, 9. Thereafter each support tube 8, 9 is driven with equal torque, through the differential 10, wherein the differential 10 has an outer dimension that is approximately equal to or smaller than the outer dimension D2 of the support tubes 8, 9.
In an embodiment, it may be desired to use the same spindle 2 for processing one single roll 12. Such roll 12 may be longer than one of the tubes 8, 9. Continuing with step 180, the spindle 2 is blocked before mounting the single roll 12 onto the spindle 2. After blocking, the single roll 12 is mounted onto the spindle, as indicated by step 190. In step 200, the single roll 12 is slit over the differential 10 to put it in position so that it partly extends over both support tubes 8, 9. The tubes 8, 9 remain blocked. In step 210, the grip arrangement may be actuated to secure the roll 12 to the support tubes 8, 9. In a further step 220 the roll 12 may be processed.
In an embodiment, the method and spindle allow repetitive mounting of the rolls 3, 4 onto a pre-assembled spindle 2 so that the roll 3, 4 are each supported by a support tube 8, 9. In between mounting different rolls 3, 4, the spindle 2 does not need to be disassembled or re-assembled and no additional components are needed. The fact that the differential 10 is adapted to have an equal or smaller outer dimension D1 than the outer dimension D2 of the support tubes 8, 9 allows for one or multiple rolls 3, 4, 12 of different lengths to be readily exchanged and positioned onto the spindle 2. Moreover, the spindle 2 may perform its function on different systems 1, for example conventional systems, for example printing systems, without needing to adapt the respective system 1.
In an embodiment, the spindle 2 may be provided in the form of a kit of parts for building the spindle 2. Such kit may comprise at least two support tubes 8, 9 of approximately equal outer dimensions D2, and a differential 10 arranged to engage the support tubes 8, 9 for transmitting an equal torque to each of the tubes 8, 9, having an outer dimension D1 that is approximately equal to or smaller than the outer dimensions D2 of the support tubes 8, 9. Further parts may include a transmission drive 11A, a blocking arrangement 27, etc.
Certain embodiments of the spindle 2 allow mounting of one or more rolls 3, 4, 12 along substantially the full length of the spindle 2. In one embodiment, the spindle 2 has a length of at least approximately 3 meter and is arranged to drive at least two rolls of at least approximately 1.50 meters with equal torque and/or equal roll material advance speed. In an embodiment, there may be a small gap between two rolls 3, 4 top prevent roll material overlap. In the shown embodiments, the differential 10 is placed approximately in the middle of the spindle 2 and the support tubes 8, 9 have approximately the same size. In other embodiments, the support tubes 8, 9 may have different sizes.
When mounting two rolls onto the spindle 2 in a printing system, the spindle 2 may provide for different angular speeds of the tubes 8, 9 for maintaining the same linear advance speeds of the respective media.
The above description is not intended to be exhaustive or to limit the invention to the embodiments disclosed. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. The indefinite article “a” or “an” does not exclude a plurality, while a reference to a certain number of elements does not exclude the possibility of having more elements. A single unit may fulfil the functions of several items recited in the disclosure, and vice versa several items may fulfil the function of one unit.
In the following claims, the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Multiple alternatives, equivalents, variations and combinations may be made without departing from the scope of the invention.

## Claims

1. A spindle of a large format printer for selectively supporting a single roll or multiple rolls of print medium, the spindle comprising:
two elongated roll supports for supporting rolls of print medium;
a differential disposed between the two elongated roll supports, the differential having two outputs, each differential output being connected to one of the roll supports;
a drive;
a transmission shaft extending from the drive, through an interior of one of the roll supports to the differential, such that an equal amount of torque is transmitted from the drive through the transmission shaft and differential to each of the elongated roll supports; and
a blocking arrangement for selectively preventing the two elongated roll supports from rotating with respect to each other such that a single roll of print medium spanning a portion of each of the roll supports can be printed on.

2. The spindle of claim 1, wherein the differential does not protrude from an outer diameter of the roll supports such that the single roll of print medium covers the differential when supported by both of the two roll supports.

3. The spindle of claim 1, wherein the differential comprise a ball differential.

4. The spindle of claim 1, wherein the blocking arrangement selectively blocks either of the roll supports from rotating with respect to the transmission shaft.

5. The spindle of claim 4, wherein the blocking arrangement comprises notches provided around the transmission shaft for engaging a latch of the blocking arrangement.

6. The spindle of claim 1, further comprising a grip arrangement to prevent slipping of the rolls of print medium with respect to the roll supports.

7. The spindle of claim 6, further comprising an actuation mechanism of the grip arrangement extending through the differential to centrally actuate the grip arrangement for both roll supports.