Patent Description:
In the context of the application, a shedding unit is defined as a unit comprising one or more driving devices, which can be drivingly coupled to heald frames of a weaving machine for moving the heald frames up and down. For a movement of the heald frames, driving devices having a swivel lever with two or three arms are well known, wherein a rotating crank is coupled via a coupling rod to a first arm of the lever and the heald frame is coupled to a second arm of the lever. The heald frames are moved up and down with a stroke, which depends among others on the length of the crank, the length of the coupling rod, and the coupling positions of the coupling rod and the heald frame on the first arm and the second arm, respectively. In the context of the application, a shed stroke of a driving device for a shedding unit is defined as the stroke imparted by the driving device on the swivel lever or any similar connection element.

<CIT> shows a shedding unit, wherein the number of driving devices of the shedding unit is the same as the number of heald frames, and each driving device is configured for moving exactly one heald frame drivingly coupled to the driving device. The driving devices each comprise a rotating crank, a swivel lever, and a coupling rod connecting the swivel lever with the crank, wherein the coupling rod is mounted to a first arm of the swivel lever by means of a mounting element. The mounting element is slidably mounted to the first arm and fixable in an adjustable mounting position at the first arm for adjusting a shed stroke of the driving device.

<CIT> shows a driving device for a shedding unit, the driving device comprising a crank constituted by two crank elements, which are connected so that the connecting angle between the two crank elements can be changed, wherein the first crank element is concentrically mounted to a driving shaft and provided with a connecting shaft, which connecting shaft is eccentric to the driving shaft, i.e. is arranged parallel but offset to the axis of rotation of the driving shaft, wherein the second crank element is mounted to the connecting shaft, and wherein the second crank element is provided with a connecting pin for a coupling rod, which connecting pin is parallel but offset to the axis of rotation of the connecting shaft. For a connection with the driving shaft, the first crank element comprises a split clamping part for clamping the driving shaft and a screw bolt arranged tangentially to the driving shaft for tightening the split clamping part. Similar, for a connection with the connecting shaft, the second crank element comprises a split clamping part for clamping the connecting shaft and a screw bolt for tightening the split clamping part. In order to adjust the shed stroke, the connecting angle between the two crank elements is changed. For this purpose, the split clamping part of the second crank element is loosened, and the second crank element is moved relative to the first crank element.

It is the object of the invention to provide a driving device, wherein a shed stroke can be easily adjusted. It is further the object of the invention, to provide a method for adjusting a shed stroke as well as a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method for adjusting a shed stroke of a driving device for a shedding unit.

This object is solved by the driving device with the features of claim <NUM>, the weaving machine with the features of claim <NUM>, and the method with the features of claim <NUM>.

According to a first aspect, a driving device for a shedding unit is provided, the driving device comprising a rotationally mounted drive element, a crank, and a locking unit, wherein the drive element has an axis of rotation, a first end, and a second end, wherein the first end and the second end are distanced from each other in the direction of the axis of rotation of the drive element, wherein the drive element is provided at the second end with a seat, wherein the crank is provided with a coupling element, which coupling element cooperates with the seat for mounting the crank to the drive element so as to be rotatable about a seat axis of the seat, which seat axis is parallel but offset to the axis of rotation of the drive element, wherein for a rotation about the axis of rotation of the drive element together with the drive element, the crank is releasably lockable to the drive element in different angular positions with respect to the drive element by the locking unit, and wherein when the crank is unlocked from the drive element, for adjusting the angular position of the crank with respect to the drive element, the driving device is configured to move the drive element about the axis of rotation of the drive element for causing a relative movement between the drive element and the crank about the seat axis, wherein means are provided for restricting a movement of a distal end of the crank to movement along a defined path, when unlocking the crank from the drive element and moving the drive element about the axis of rotation of the drive element.

A movement of the distal end of the crank is restricted to movement along a defined path upon adjusting the shed stroke. When unlocking the crank from the drive element, and restricting a movement of the distal end of the crank to a defined path while moving the drive element about the axis of rotation of the drive element, a movement of the drive element about the axis of rotation of the drive element causes a defined adjustment of the angular position of the crank with respect to the drive element.

In the context of the application, a rotary movement of an element about an axis is referred to as movement about an axis, wherein the movement may be less or more than a full rotation about the axis.

In one embodiment, the driving devices are used in a shedding unit, wherein the number of driving devices of the shedding unit is the same as the number of heald frames. In other words, each driving device is configured for moving exactly one heald frame drivingly coupled to the driving device. However, it is generally conceivable within the context of the application to couple more than one heald frame to a common driving device, wherein the driving device in one embodiment is configured to move two heald frames in opposite directions.

The driving device according to the application allows for an easy adjustment of the shed stroke. In prior art document <CIT>, the drive element and the crank are referred to as first crank element and second crank element, respectively. In contrast to <CIT>, for an adjustment of the angular position between the drive element and the crank, when the crank is unlocked from the drive element, according to the application the drive element and not the crank, to which a heald frame can be coupled, is moved.

In one embodiment, a drive motor is provided, which drive motor is configured to drive the drive element so as to move about the axis of rotation of the drive element. The drive motor is driving the drive element to rotate about the axis of rotation together with the crank for an up and down movement of a heald frame coupled to the driving device. In addition, when the crank is unlocked from the drive element, the drive motor can be used for displacing or moving the drive element by a certain angle about the axis of rotation for an adjustment of the angular position of the crank with respect to the drive element.

In one embodiment, the locking unit allows for an automated operation. For example, in one embodiment, the locking unit is in the form of a hydraulic expansion chuck, wherein a hydraulic pressure acting between the seat and the coupling element can be varied for locking the crank to the drive element or unlocking the crank from the drive element. In an alternative embodiment, the locking unit is in the form of a pneumatic and/or hydraulic actuable clutch. In still another embodiment, the locking unit comprises at least one pneumatic and/or hydraulic cylinder and a return spring, which cylinder is moveable for unlocking the locking unit by applying a pneumatic and/or hydraulic pressure.

In alternative or in addition, the locking unit is manually operable, wherein in one embodiment the locking unit is accessible for a manual operation from a first end of the drive element for locking the crank to the drive element or for unlocking the crank from the drive element. For example, the shedding unit comprises a plurality of driving devices, which are arranged in two opposing groups, wherein the second ends of the drive elements of the two groups are facing towards a center of the shedding unit. In this case, the first ends are arranged at an outer side of the shedding unit and more easily accessible for an operator, than the second ends. This first end allows for an easy access for an operator for an adjustment of the shed stroke.

In one embodiment, the coupling element and the seat are arranged for locking the crank to the drive element by forcing the crank and the drive element towards each other in the direction of the seat axis, wherein the locking unit is actuable for causing a movement of the crank towards or away from the drive element in the direction of the seat axis.

In one embodiment, one of the coupling element and the seat is a member in the form of a truncated cone and the other one is a complementary receiving bushing. In other words, a conical seat connection is provided, which is backlash-free and self-centering. In addition, a locking and unlocking is possible by moving the coupling element a short distance with respect to the seat.

In one embodiment, the locking unit comprises a locking pin, which locking pin is moveably mounted to the drive element and is moveable in one direction for locking the crank to the drive element and in an opposite direction for unlocking the crank from the drive element. In one embodiment, the locking pin is slidably supported. In alternative or in addition, the locking pin is rotatably supported. In preferred embodiments, the locking pin has an actuating end configured to receive an actuating force for moving the locking pin with respect to the drive element, which actuating end is arranged at the first end of the drive element. The actuating end in one embodiment is provided with a screw head for the application of a rotational movement and/or a torque.

In one embodiment, the locking pin is mounted to the drive element so as to be longitudinally moveable along the seat axis, wherein the crank can be coupled to the locking pin for movement with the locking pin along the seat axis, for causing a movement of the crank towards or away from the drive element in the direction of the seat axis by axial movement of the locking pin. In one embodiment, the locking pin is forced in a locking position using a restoration element and is moveable against the force of a restoration element using for example a pneumatic and/or hydraulic cylinder.

In other embodiments, the locking unit comprises a locking pin that is mounted to or arranged in the drive element so as to be rotatable about the seat axis, wherein the locking pin is provided with an actuating end configured to receive an actuating force for moving the locking pin with respect to the drive element, and wherein the locking pin is provided with a threaded end opposite to the actuating end, which threaded end cooperates with a threaded hole of the crank for causing a movement of the crank towards or away from the drive element in the direction of the seat axis by rotating the locking pin. In other words, the locking pin and the crank act as a spindle drive causing a movement of the crank in the direction of the seat axis by rotating the locking pin about the seat axis.

The coupling element is provided at a proximal end of the crank, wherein a subsequent link such as a connecting rod is coupled to a distal end of the crank, for example using a hinged joint. In the context of the invention, a proximal end and a distal end of a crank are defined as the regions of the crank in which the crank can be coupled to a drive element and a subsequent link, such as a connecting rod, respectively. The length of the crank may be chosen such that a part of the crank extends beyond the proximal end and/or the distal end. In one embodiment, the distal end is not coupled to any element when adjusting a shed stroke, wherein the distal end is free to move.

In embodiments, the driving device further comprising a link coupled with its first end to the distal end of the crank by a hinged joint, wherein when the crank is unlocked from the drive element, the drive element, the crank and the link together form a planar quadrilateral linkage. When adjusting the angular position of the crank with respect to the drive element, a second end of the link can be held fixed in position while moving the drive element about the axis of rotation of the drive element, and allowing the link to rotate about the second axis, thereby restricting the movement of the distal end of the crank about the seat axis.

In embodiments, the driving device further comprising a swivel lever having a first arm and a second arm, wherein the swivel lever is swivelable to-and-fro about a swivel axis between a first position associated with an upper position of a heald frame coupled to the swivel lever and a lower position associated with a lower position of the heald frame coupled to the swivel lever, a coupling rod, which is linked to the crank by a first hinged joint, wherein the coupling rod is linked to the first arm of the swivel lever by a second hinged joint, wherein for adjusting the angular position of the crank with respect to the drive element, the second hinged joint, the swivel lever and/or the heald frame coupled to the driving device is/are held in position while moving the drive element about the axis of rotation of the drive element, thereby restricting the movement of the distal end of the crank to a defined path.

According to a second aspect, a weaving machine with such a driving device is provided.

According to a third aspect, a method for adjusting a shed stroke of a driving device for a shedding unit is provided, the driving device comprising a rotationally mounted drive element, a crank, and a locking unit, wherein the drive element has an axis of rotation, a first end, and a second end, wherein the first end and the second end are distanced from each other in the direction of the axis of rotation of the drive element, wherein the drive element is provided at the second end with a seat, wherein the crank is provided with a coupling element, which coupling element cooperates with the seat for mounting the crank to the drive element so as to be rotatable about a seat axis of the seat, which seat axis extends parallel but offset to the axis of rotation of the drive element, wherein for a rotation about the axis of rotation of the drive element together with the drive element the crank is releasably lockable to the drive element in different angular positions with respect to the drive element by the locking unit, wherein when the crank is unlocked from the drive element, for adjusting the angular position of the crank with respect to the drive element, the drive element is moved about the axis of rotation of the drive element for causing a relative movement between the drive element and the crank about the seat axis, wherein a movement of a distal end of the crank is restricted to a movement along a defined path, when unlocking the crank from the drive element and moving the drive element about the axis of rotation of the drive element.

In one embodiment, the drive element is driven to move about the axis of rotation of the drive element by a drive motor when the crank is unlocked from the drive element for adjusting the angular position of the crank with respect to the drive element.

A movement of the distal end of the crank is restricted while moving the drive element, for example due to a link coupled to the distal end of the crank, which together with the drive element and the crank forms a planar quadrilateral linkage when the crank is unlocked from the drive element.

In one embodiment, a heald frame coupled to the crank is held in position while driving the drive element so as to move, in particular so as to rotate, about the axis of rotation of the drive element when the crank is unlocked from the drive element for restricting a movement of the distal end of the crank.

In one embodiment, for adjusting the angular position of the crank with respect to the drive element, the drive element is moved about the axis of rotation of the drive element in a direction associated with an upward movement of the heald frame coupled to the crank. In this case, gravitational forces acting on the heald frame coupled to the driving device can be used for holding the heald frame in position while moving the drive element when the crank is unlocked from the drive element.

According to a fourth aspect, a computer program for use with the driving device is provided, the computer program comprising instructions which, when the program is executed by a computer, cause the computer to drive the drive motor for adjusting a shed stroke of the driving device when the crank is unlocked from the drive element, wherein the drive element is driven to move about the axis of rotation of the drive element by the drive motor for causing a relative movement between the drive element and the crank about the seat axis.

In one embodiment, the computer program further comprises instructions which, when the program is executed by the computer, cause the computer to determine a direction of rotation of the drive element associated with an upward movement of a heald frame coupled to the crank.

In one embodiment, the computer program further comprises instructions which, when the program is executed by the computer, cause the computer to determine a reference angular position of the crank with respect to the drive element for setting a desired stroke of the heald frame coupled to the crank. In case the movement of the distal end of the crank is restricted when moving the drive element along a known path, the computer program may further comprise instructions which, when the program is executed by the computer, cause the computer to determine a necessary movement of the drive element about the axis of rotation for achieving a relative movement of the crank with respect to the drive element into said reference angular position.

Throughout the drawings, the same or similar elements will be denoted by the same reference numerals.

<FIG> and <FIG> show a shedding unit <NUM> and a heald frame <NUM> of a weaving machine. Although only one heald frame <NUM> is visible, the weaving machine comprises a number of heald frames <NUM>, which are guided in a frame guide (not shown) of the weaving machine and driven to move up and down.

As shown in the perspective view of <FIG>, the shedding unit <NUM> comprises several driving devices <NUM>, wherein the number of driving devices <NUM> in the embodiment shown is the same as the number of heald frames <NUM>. In other words, one driving device <NUM> is assigned to one heald frame <NUM>, which heald frame <NUM> is coupled to the associated one driving device <NUM>. In the embodiment shown in <FIG>, the shedding unit <NUM> comprises eight driving devices <NUM> according to the invention. In an alternative embodiment, a different number of driving devices may be provided, for example a number of sixteen driving devices as shown in <CIT>. In an embodiment, a shedding unit <NUM> having a number of driving devices <NUM> can also be used for driving a number of heald frames <NUM> which is less than the number of driving devices <NUM>, wherein a number of driving devices <NUM> are not used during weaving.

The driving devices <NUM> each comprise a crank <NUM>, which is driven to rotate about an axis of rotation <NUM> (see <FIG>), a coupling rod <NUM>, and a first swivel lever <NUM>. The first swivel lever <NUM> is swivelable to-and-fro about a swivel axis <NUM> between an upper position and a lower position. The swivel axis <NUM> is arranged stationary in a support <NUM>. The driving device <NUM> shown in <FIG> further comprises a second swivel lever <NUM>, that is swivelable to-and-fro about a second swivel axis <NUM> between an upper position and a lower position. The second swivel lever <NUM> is linked to the first swivel lever <NUM> by means of a connecting rod <NUM> and driven by the first swivel lever <NUM> to conjointly move with the first swivel lever <NUM>. In the embodiment of <FIG>, for example, the heald frame <NUM> is linked to the first swivel lever <NUM> by means of a first lifting rod <NUM> and to the second swivel lever <NUM> by means of a second lifting rod <NUM>. In an alternative embodiment, preferably in case of wide heald frames, more than two swivel levers, associated connecting rods and associated lifting rods can be provided.

As generally known, for moving the heald frames <NUM> up and down, the crank <NUM> is driven to rotate about an axis of rotation <NUM>, thereby causing a to-and-fro movement of the first swivel lever <NUM> about the swivel axis <NUM>. Each driving device <NUM> comprises a drive motor <NUM>, wherein the driving devices <NUM> are arranged in the shedding unit <NUM> such that the drive motors <NUM> are arranged at an outer side of the shedding unit <NUM> and the coupling rods <NUM> are arranged close to one another. In a preferred embodiment, the coupling rod <NUM> and the connecting rod <NUM> extend almost in line with each other, so that forces on the swivel axis <NUM> applied by the swivel lever <NUM> are minimized. In alternative embodiments, other coupling rods and associated connecting rods can be used, for example coupling rods and connecting rods as shown in <CIT>.

<FIG> and <FIG> show a driving device <NUM> for a shedding unit <NUM> comprising a drive motor <NUM>, a crank <NUM>, a rotationally mounted drive element <NUM> (see <FIG>), and a locking unit <NUM> (see <FIG>). The drive element <NUM> is mounted via bearings in a support frame <NUM>. The rotationally mounted drive element <NUM> has an axis of rotation <NUM>, a first end <NUM>, and a second end <NUM>, wherein the first end <NUM> and the second end <NUM> are distanced from each other in the direction of the axis of rotation <NUM> of the drive element <NUM>. The drive motor <NUM> is configured to drive the drive element <NUM> so as to move the drive element <NUM> about the axis of rotation <NUM> of the drive element <NUM>. The drive motor <NUM> is arranged at the first end <NUM> of the drive element <NUM>.

The crank <NUM> is coupled at its proximal end <NUM> to the drive element <NUM> and at its distal end <NUM> to the coupling rod <NUM>. The coupling rod <NUM> can rotate about an axis of rotation <NUM> of the crank <NUM>. At the second end <NUM> of the drive element <NUM>, the drive element <NUM> is provided with a seat <NUM>, which seat <NUM> in the embodiment shown is a member in the form of a truncated cone. The crank <NUM> is provided with a coupling element <NUM>, which coupling element <NUM> in the embodiment shown is a receiving bushing, which is complementary in shape to the truncated cone of the seat <NUM>. The coupling element <NUM> cooperates with the seat <NUM> for mounting or coupling the crank <NUM> to the drive element <NUM>. The coupling element <NUM> and the seat <NUM> are arranged for locking the crank <NUM> to the drive element <NUM> by forcing the crank <NUM> and the drive element <NUM> towards each other in the direction of the seat axis <NUM>, wherein the locking unit <NUM> is actuable for causing a movement of the crank <NUM> towards or away from the drive element <NUM> in the direction of the seat axis <NUM>. Thus, when the crank <NUM> is unlocked from the drive element <NUM>, the crank <NUM> and the drive element <NUM> are rotatable relative to each other about a seat axis <NUM> of the seat <NUM>, which seat axis <NUM> is parallel but offset to the axis of rotation <NUM> of the drive element <NUM>. When the crank <NUM> is locked to the drive element <NUM>, the drive element <NUM> can be driven by the drive motor <NUM> to rotate together with the crank <NUM> about the axis of rotation <NUM> of the drive element <NUM> for causing an up and down movement of a heald frame <NUM> (see <FIG>) coupled to the crank <NUM>.

In an alternative embodiment, one of the coupling element and the seat is a member in the form of a cylinder and the other one is a complementary receiving bushing, wherein for example the front end of the cylinder and the base of the receiving bushing can be forced towards each other for locking the drive element <NUM> to the crank <NUM>.

The locking unit <NUM> is configured to releasably lock the crank <NUM> to the drive element <NUM> in different angular positions with respect to the drive element <NUM>. The locking unit <NUM> can also be referred as a fastening unit for releasably fastening the drive element <NUM> to the crank <NUM>. In the embodiment shown in <FIG> and <FIG>, the locking unit <NUM> comprises a locking pin <NUM>, which is arranged in the drive element <NUM> concentric to the seat axis <NUM> of the seat <NUM> so as to be rotatable about the seat axis <NUM>. The locking pin <NUM> has an actuating end <NUM> arranged at the first end <NUM> of the drive element <NUM>, so that the actuating end <NUM> of the locking unit <NUM> is accessible for a manual operation from the first end <NUM> of the drive element <NUM> for locking the crank <NUM> to the drive element <NUM> or for unlocking the crank <NUM> from the drive element <NUM>. Opposite to the actuating end <NUM> of the locking pin <NUM>, the locking pin <NUM> is provided with a threaded end <NUM>. The threaded end <NUM> cooperates with a threaded hole <NUM> of the crank <NUM> for causing a movement of the crank <NUM> towards or away from the drive element <NUM> in the direction of the seat axis <NUM> by rotating the locking pin <NUM> about the seat axis <NUM>, thereby locking the crank <NUM> to the drive element <NUM> or unlocking the crank <NUM> from the drive element <NUM>. Further, a grease duct <NUM> is provided allowing to grease the bearing at the distal end <NUM>, which grease duct <NUM> allows to guide grease that is supplied along the locking pin <NUM>.

<FIG> shows in a perspective view the driving device of <FIG> together with a tool <NUM> for actuating the actuating end <NUM> of the locking unit <NUM>. As described above, the locking unit <NUM> comprises a locking pin <NUM> (see <FIG>), which is moveably mounted to the drive element <NUM> and is moveable in one direction for locking the crank <NUM> to the drive element <NUM> and in an opposite direction for unlocking the crank <NUM> from the drive element <NUM>. The locking pin <NUM> has an actuating end <NUM> configured to receive an actuating force by the tool <NUM> for moving the locking pin <NUM> with respect to the drive element <NUM>, which actuating end <NUM> is arranged at the first end <NUM> of the drive element <NUM>. As described above, the locking pin <NUM> is provided with the threaded end <NUM> (see <FIG>) cooperating with the threaded hole <NUM> of the crank <NUM>, thus allowing to apply a torque by the tool <NUM> on the actuating end <NUM> of the locking pin <NUM> to move or rotate the locking pin <NUM>, and to thereby move the crank <NUM> towards or away from the drive element <NUM> in the direction of the seat axis <NUM>.

The crank <NUM> is releasably lockable to the drive element <NUM>, so that the crank <NUM> can be unlocked from the drive element <NUM> for a relative movement between the crank <NUM> and the drive element <NUM> in order to adjust the shed stroke, and so that the crank <NUM> can be locked to the drive element <NUM> in different angular positions with respect to the drive element <NUM> for a conjoint movement allowing an up and down movement of a heald frame <NUM> that is coupled to the driving device <NUM>. By an adjustment of the angular position between the drive element <NUM> and the crank <NUM>, the shed stroke of the driving device <NUM>, i.e. a swivel movement of the first swivel lever <NUM> about the swivel axis <NUM> (see <FIG>), and, thus, a stroke of the heald frame <NUM> can be set.

<FIG> and <FIG> show in a schematic front view the proximal end <NUM> of the crank <NUM> coupled to the drive element <NUM> and the distal end <NUM> of the crank <NUM> coupled to the coupling rod <NUM>. The coupling rod <NUM> is attached to the first swivel lever <NUM> via a hinged joint <NUM> allowing the coupling rod <NUM> to swivel about an axis of the hinged joint <NUM>. Further, preferably for adjusting the angular position of the crank <NUM> with respect to the drive element <NUM>, in the embodiment shown in <FIG>, a movement of the first swivel lever <NUM> about the swivel axis <NUM> is blocked by means of a blocking element <NUM> as schematically shown in <FIG> and <FIG>. Hence, when the crank <NUM> is unlocked from the drive element <NUM> for a relative movement between the crank <NUM> and the drive element <NUM>, the drive element <NUM>, the crank <NUM> and the coupling rod <NUM> form a planar quadrilateral linkage. Therefore, when the drive element <NUM> is moved about the axis of rotation <NUM> of the drive element <NUM>, a movement of the crank <NUM> with respect to the drive element <NUM> about the seat axis <NUM> of the seat <NUM> is constrained by the coupling rod <NUM>, because the movement of the coupling rod <NUM> is constrained by the first swivel lever <NUM>. This allows to impart a defined relative movement between the drive element <NUM> and the crank <NUM> when the crank <NUM> is unlocked from the drive element <NUM>. In an alternative embodiment, as shown in <FIG> and <FIG>, the blocking element <NUM> can be provided near the second swivel lever <NUM>, instead of near the first swivel lever <NUM> as shown in <FIG> and <FIG>. In an alternative embodiment, the blocking element <NUM> can be formed as a blocking element known from <CIT> of the applicant. In an alternative embodiment, a blocking element can act on another element of the shedding unit <NUM>, for example on the connecting rod <NUM>, on the heald frame <NUM>, or on still another element of the shedding unit <NUM>.

As will be explained more in detail with reference to <FIG> and <FIG>, for adjusting the angular position of the crank <NUM> with respect to the drive element <NUM>, the driving device <NUM> is configured to move the drive element <NUM> about the axis of rotation <NUM> of the drive element <NUM> for causing a relative movement between the drive element <NUM> and the crank <NUM> about the seat axis <NUM>.

When the crank <NUM> is mounted to the drive element <NUM>, the drive element <NUM> and the crank <NUM> rotate together about the axis of rotation <NUM>. The coupling rod <NUM> is mounted to the crank <NUM> to rotate about an axis of rotation <NUM> of the crank <NUM>. The distance between the axis of rotation <NUM> and the axis of rotation <NUM> is referred to as first eccentricity <NUM>. The crank <NUM> is mounted to the drive element <NUM> so as to rotate about the seat axis <NUM> when the crank <NUM> is unlocked from the drive element <NUM>. The distance between the axis of rotation <NUM> and the seat axis <NUM> is referred to as second eccentricity <NUM>. The distance between the seat axis <NUM> and the axis of rotation <NUM> is referred to as the third eccentricity <NUM>, also named the crank length of the crank <NUM>. When the crank <NUM> is mounted to the drive element <NUM>, the first eccentricity <NUM> defines a circular trajectory <NUM> along which the axis of rotation <NUM> moves, in other words the circular trajectory <NUM> along which the distal end <NUM> of the coupling rod <NUM> is moved by the crank <NUM>. The seat axis <NUM> moves along a circular trajectory <NUM> by rotating the drive element <NUM>.

The first eccentricity <NUM> depends on the second eccentricity <NUM>, the third eccentricity <NUM>, and the relative angular position between the drive element <NUM> and the crank <NUM>. <FIG> shows in a schematic front view a first mutual positioning of the eccentricities <NUM>, <NUM>, <NUM>, wherein the crank <NUM> or third eccentricity <NUM> is arranged in a first angular position with respect to the drive element <NUM> or the second eccentricity <NUM>, while <FIG> shows the third eccentricity <NUM> arranged in a different second angular position with respect to the second eccentricity <NUM>. As shown in <FIG> and <FIG>, by adjusting the angular position of the third eccentricity <NUM> with respect to the second eccentricity <NUM>, in other words by adjusting the angular position of the crank <NUM> with respect to the drive element <NUM> by rotating the crank <NUM> about the seat axis <NUM>, the first eccentricity <NUM> of the driving device <NUM> is adjusted, and, thus, a shed stroke of the driving device <NUM> can be adjusted.

For adjusting the angular position of the crank <NUM> with respect to the drive element <NUM>, in particular for adjusting this angular position from a mutual positioning as shown in <FIG> to a mutual positioning as shown in <FIG>, and, thus, in order to adjust the shed stroke, preferably the heald frame <NUM> (see <FIG>) is moved to an upper position by the drive motor <NUM>, a blocking element <NUM> is provided in the range of a first swivel lever <NUM>, in particular under the first swivel lever <NUM>, and the heald frame <NUM> is moved by the drive motor <NUM> until the first swivel lever <NUM> abuts against the blocking element <NUM>.

Then, the locking pin <NUM> of the locking unit <NUM> (see <FIG>) is rotated for unlocking the crank <NUM> from the drive element <NUM> by means of a tool <NUM> that cooperates with the actuating end <NUM> of the locking pin <NUM>, so that the crank <NUM> is unlocked from the drive element <NUM>, and so that the crank <NUM> is rotatable about the seat axis <NUM> of the seat <NUM> (see <FIG>) of the drive element <NUM> by driving the drive element <NUM> by the drive motor <NUM>. By driving the drive motor <NUM>, the drive element <NUM> is moved about the axis of rotation <NUM> of the drive element <NUM>, and when the crank <NUM> is unlocked from the drive element <NUM>, the angular position of the crank <NUM> with respect to the drive element <NUM> can be adjusted, for example between the positions of <FIG> and <FIG>. Due to the blocking element <NUM>, the heald frame <NUM> coupled to the crank <NUM> is held in position while driving the drive element <NUM> by the drive motor <NUM>, so as to move the drive element <NUM> about the axis of rotation <NUM>. When the crank <NUM> is unlocked from the drive element <NUM>, a movement of the distal end <NUM> of the crank <NUM> is restricted. Preferably, for adjusting the angular position of the crank <NUM> with respect to the drive element <NUM>, the drive element <NUM> is moved by the drive motor <NUM> about the axis of rotation <NUM> of the drive element <NUM> in a direction associated with an upward movement of the heald frame <NUM> coupled to the crank <NUM>.

After adjusting is completed, for example when the position of <FIG> is reached, the crank <NUM> is locked again to the drive element <NUM>, for example by rotating the locking pin <NUM> of the locking unit <NUM> by means of the tool <NUM> (see <FIG>). In the meanwhile, the blocking element <NUM> is moved away from the swivel lever <NUM>, in other words the blocking element <NUM> is displaced so that the blocking element <NUM> cannot make any contact with the first swivel lever <NUM> and does not hinder the movement of the first swivel lever <NUM>. Now, by means of the drive motor <NUM>, the crank <NUM> can be rotated together with the drive element <NUM> and the crank <NUM> can move the first swivel lever <NUM> with a set shed stroke causing a movement of the heald frame <NUM> over a set stroke.

In order to drive the drive motor <NUM> for setting or adjusting the shed stroke, a computer program comprising instructions is used, which computer program, when the program is executed by a computer, causes the computer to carry out the adjustment method as explained above. The computer program comprising in one embodiment instructions which, when the program is executed by the computer, cause the computer to determine a direction of rotation of the drive element <NUM> associated with an upward movement of a heald frame <NUM> coupled to the crank <NUM>, in other words a movement of the heald frame <NUM> for moving the first swivel lever <NUM> away from the blocking element <NUM>. This prevents that the shedding unit <NUM> could be damaged by driving the drive motor <NUM>, in case the locking unit <NUM> would be not unlocked well.

Further the computer program in one embodiment comprises instructions which, when the program is executed by the computer, cause the computer to determine a reference angular position of the crank <NUM> with respect to the drive element <NUM> for setting a desired stroke of the heald frame <NUM> coupled to the crank <NUM>. For example, a mutual angular position for a shed stroke defined by the circular trajectory <NUM> as shown in <FIG> or another mutual angular position for a shed stroke defined by the circular trajectory <NUM> as shown in <FIG>, which will cause a stroke of the heald frame <NUM>, which further depends on a coupling position of the first lifting rod <NUM> (see <FIG>) on the first swivel lever <NUM>. For moving the crank <NUM> with respect to drive element <NUM> into the determined reference angular position, in one embodiment a state of the driving device <NUM> is chosen, in which the swivel lever <NUM> makes contact with the blocking element <NUM>. In this way, the movement of the distal end <NUM> of the crank <NUM> is constrained by the coupling rod <NUM> to a circular path having its center at the hinged joint <NUM>. Hence, the orientation or the direction of the drive element <NUM> and, thus, the second eccentricity <NUM> as shown in <FIG>, defines the reference angular position of a starting shed stroke shown in <FIG>, and the orientation or the direction of the second eccentricity <NUM> as shown in <FIG> defines the reference angular position of a desired starting shed stroke shown in <FIG>. The person skilled in the art will understand that the reference angular positions and the shed strokes shown in <FIG> and <FIG> are given only as examples.

Claim 1:
A driving device for a shedding unit (<NUM>), the driving device (<NUM>) comprising a rotationally mounted drive element (<NUM>), a crank (<NUM>), and a locking unit (<NUM>), wherein the drive element (<NUM>) has an axis of rotation (<NUM>), a first end (<NUM>), and a second end (<NUM>), wherein the first end (<NUM>) and the second end (<NUM>) are distanced from each other in the direction of the axis of rotation (<NUM>) of the drive element (<NUM>), wherein the drive element (<NUM>) is provided at the second end (<NUM>) with a seat (<NUM>), wherein the crank (<NUM>) is provided with a coupling element (<NUM>), which coupling element (<NUM>) cooperates with the seat (<NUM>) for mounting the crank (<NUM>) to the drive element (<NUM>) so as to be rotatable about a seat axis (<NUM>) of the seat (<NUM>), which seat axis (<NUM>) is parallel but offset to the axis of rotation (<NUM>) of the drive element (<NUM>), wherein for a rotation about the axis of rotation (<NUM>) of the drive element (<NUM>) together with the drive element (<NUM>), the crank (<NUM>) is releasably lockable to the drive element (<NUM>) in different angular positions with respect to the drive element (<NUM>) by the locking unit (<NUM>), characterized in that when the crank (<NUM>) is unlocked from the drive element (<NUM>), for adjusting the angular position of the crank (<NUM>) with respect to the drive element (<NUM>), the driving device (<NUM>) is configured to move the drive element (<NUM>) about the axis of rotation (<NUM>) of the drive element (<NUM>) for causing a relative movement between the drive element (<NUM>) and the crank (<NUM>) about the seat axis (<NUM>), wherein means are provided for restricting a movement of a distal end (<NUM>) of the crank (<NUM>) to movement along a defined path, when unlocking the crank (<NUM>) from the drive element (<NUM>) and moving the drive element (<NUM>) about the axis of rotation (<NUM>) of the drive element (<NUM>).