A driving-force transmission mechanism includes a driving-force transmission shaft that is provided so as to protrude from a side wall of a side frame while extending parallel to a driving shaft 30 within a space of the side frame, the driving-force transmission shall being connected to a driving motor, and to which an opening device is connected, and a transmission mechanism that connects the driving-force transmission shaft and the driving shaft, and a braking device is connected to the driving-force transmission shaft.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2020-097695, filed on Jun. 4, 2020, the entire subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a loom including a driving shaft to which a main shaft of the loom is connected and to which a swing shaft for driving a reed to swing is connected via a swing mechanism, a driving motor to which the driving shaft is connected via a driving-force transmission mechanism to rotationally drive the driving shaft, an opening device that is driven by the driving motor, a braking device that applies a brake to the main shaft, and a side frame that accommodates the driving shaft and the swing shaft in an orientation in which each axial direction of the driving shaft and the swing shaft matches with a width direction.

Background Art

A loom has a shaft (driving shaft) of which one end is connected a main shaft and which is rotationally driven by a driving motor. In a general loom, the driving shaft is accommodated in one of a pair of side frames in a frame of the loom. The driving shaft is rotationally driven by the driving motor, so that the main shaft connected to the driving shaft is rotationally driven. The rotation of the driving shaft is also driving the reed to swing. Specifically, a swing shaft for driving the reed to swing is also accommodated in the one side frame, and the swing shaft is connected to the driving shaft via a swing mechanism such as a cam mechanism and a crank mechanism. As described above, the loom is configured such that the swing shaft is swing-driven as the driving shaft is rotationally driven, whereby the reed is driven to swing.

As described above, the configuration (driving-force transmission mechanism) that connects the driving shaft and the driving motor for rotationally driving the driving shaft by the driving motor is disclosed in JP-A-H5-156551. In a configuration that is disclosed in JP-A-H5-156551 (hereinafter, referred to as the “configuration of the related art”), an intermediate shaft, which is connected to the driving motor by a pulley and a timing belt, is provided between the driving shaft to which a swing mechanism is connected and the driving motor. The intermediate shaft and the driving shaft are connected by a gear train.

The loom includes an opening device that displaces a heddle frame in a vertical direction in order to give an opening motion to the warps. The opening device is provided in a form of being connected to the driving shaft so as to use the driving motor as a driving source, except for a type driven by a dedicated motor. Therefore, in such a loom, the driving motor and the opening device are connected to the driving shaft. However, in the configuration of the related art, the opening device is connected to the intermediate shaft connected to the driving motor in the form described above. That is, in the configuration of the related art, the driving motor and the opening device are connected to the driving shaft via the intermediate shaft and a gear train.

The loom includes a braking device for applying a brake to the main shaft. In the configuration of the related art, the braking device is connected to the other end of the driving shaft and is configured to apply a brake to the main shaft by apply a brake to the driving shaft.

As described above, in the configuration of the related art in which the braking device is connected to an end of the driving shaft, when the brake is applied to the driving shaft to apply the brake to the main shaft, a braking force that tries to stop the rotation acts on the intermediate shaft via the gear train. When the brake is applied to the intermediate shaft as described above, the brake is also applied to the driving motor connected to the intermediate shaft and the opening device. Therefore, an inertia force due to the brake of the driving motor and the opening device acts on the intermediate shaft. Therefore, in the gear train that connects the driving shaft to which the brake is applied and the intermediate shaft that tries to rotate against the braking force by the action of the inertia force, a load corresponding to the inertia force is applied to a meshing portion between a gear on a driving shaft side and a gear on an intermediate shaft side. As a result, the gear train may be damaged.

In a case where a width dimension of the heddle frame is large as in that of a wide loom, in a case where the number of heddle frames mounted on the loom or used for weaving is large, or the like, the inertia force due to the brake of the opening device is further increased. Since the driving force of the driving motor that drives the opening device is also further increased, the inertia force in accordance with the brake of the driving motor is also further increased. Therefore, in such a case, the load applied to the gear train is further increased as described above during braking by the braking device, so that the damage thereof or the like is more likely to occur.

As a connection configuration for connecting the driving shaft and the intermediate shaft, a combination of a pulley and a timing belt can be considered in addition to the gear train. However, even in the case of the configuration, since the intermediate shaft is rotated by the inertia force with respect to the braked driving shaft, a load corresponding to the inertia force is applied to the timing belt connecting the driving shaft and the intermediate shaft. As a result, the timing belt may be damaged or the like.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a structure of a loom in which damage of the above-mentioned connection configuration can be prevented as much as possible during braking by a braking device.

To achieve the above object, the present invention provides the loom as described above, in which the driving-force transmission mechanism includes a driving-force transmission shaft that is provided so as to protrude from a side wall of the side frame while extending parallel to the driving shaft within a space of the side frame, the driving-force transmission shaft being connected to the driving motor, and to which the opening device is connected, and a transmission mechanism that connects the driving-force transmission shaft and the driving shaft, and the braking device is connected to the driving transmission shaft.

According to the loom according to the present invention, by the configuration, a load applied to the connection configuration that connects the driving shaft and the driving-force transmission shaft is small during braking by the braking device. More specifically, during the braking, the brake is applied to the driving shaft and the driving transmission shaft. Therefore, an inertia force due to the brake of connected configuration elements acts on each of the driving shaft and the driving transmission shaft. As described above, the driving-force transmission shaft is connected to the driving motor and the opening device as the configuration elements. The driving shaft is connected to the main shaft, a beating device, and the like as the configuration elements.

As in the configuration of the related art or the configuration according to the present invention, in a case of a configuration in which one or more configuration elements are connected to each other and the braking device is connected to one of two shafts connected to each other by the connection configuration, a brake is directly applied to one shaft (braking shaft) by the braking device, and thereby the other shaft (braked shaft) receives the braking force via the connection configuration. In other words, the connection configuration becomes a portion acting the braking force by the braking shaft on the braked shaft.

The inertia force due to the configuration elements acting on each shaft as the brake is applied to each shaft naturally acts in a rotational direction of the shaft. Therefore, on the braking shaft side, the inertia force acts in a direction of weakening the braking force of the braking device. Therefore, the braking force, which is acted on the connection configuration by the braking shaft, is a force weakened by the inertia force acting on the braking shaft side by the braking force that the braking device tries to act on the braking shaft. On the other hand, the inertia force acting on the braked shaft is a force against the braking force (braking force that the braking shaft acts on the connection configuration) that the braked shaft receives from the connection configuration. Therefore, the greater the inertia force acting on the braking shaft (the smaller the braking force that braking shaft acts on the connection configuration), the smaller load is applied to the connection configuration. In addition, the greater the inertia force acting on the braked shaft, (the greater the force against the braking force received from the connection configuration), the greater the load is applied to the connection configuration.

In the loom, during the braking, the inertia force acting on the shaft (driving transmission shaft) by the driving motor and the opening device is generally greater than the inertia force acting on the shaft (driving shaft) by the main shaft, the beating device, or the like. Therefore, compared with the configuration of the related art in which the driving shaft is the braking shaft, the load applied to the connection configuration during the braking is small in the configuration of the present invention in which the driving-force transmission shaft is the braking shaft. Therefore, according to the present invention, damage to the connection configuration is prevented as much as possible.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment (example) of a loom to which the present invention is applied will be described with reference toFIGS.1and2.

In a loom1, a frame10includes a pair of housing-shaped side frames12and12, and the side frames12are configured to be connected by a plurality of beam materials. The loom1includes a driving motor20, and is configured to drive a main shaft5of the loom1by the driving motor20. The driving motor20is provided on one side frame12(hereinafter, referred to as “driving-side frame”) side of the pair of side frames12and12.

The driving-side frame12is configured of a frame body14that is a main portion, and a frame cover16attached to the frame body14. Specifically, the frame body14is formed in a housing shape having a space therein, and a portion (portion corresponding to a swing mechanism60or the like described later in a width direction) in a side wall (outer wall portion)14a, which is an outside in the width direction of the loom1, is open. The frame cover16is a member formed in a plate shape, and has a size capable of covering an opened portion (opening portion)14cof the frame body14. The driving-side frame12is configured such that the frame cover16is attached to the frame body14in a form of covering the opening portion14c. Therefore, the side wall (outer wall)12aof the driving-side frame12that is the outside in the width direction is configured of the outer wall portion14aof the frame body14and the frame cover16that covers the opening portion14cthereof. The frame cover16is attached to the frame body14by using screw members (not illustrated) such as bolts, and the frame cover16can be attached or detached to or from the frame body14.

The loom1includes a driving shaft30which is interposed between a driving motor20and a main shaft5, is rotationally driven by the driving motor20, and rotationally drives the main shaft5. The loom1includes a swing shaft50for driving a locking shaft44to swing in a beating device40, and a swing mechanism60for connecting the swing shaft50and the driving shaft30. The present example is an example in which a crank mechanism is adopted as the swing mechanism60. The driving shaft30, the swing shaft50, and the swing mechanism60are disposed to be located within a range of the opening portion14cin the driving-side frame12as viewed in the width direction, and are accommodated in the space within the driving-side frame12. Details of each configuration in such a loom1are as follows.

The driving shaft30is formed as a shaft having a dimension (length dimension) in an axial direction, which is larger than a dimension of the driving-side frame12in the width direction. However, the driving shaft30is a crank-shaped shaft formed as an eccentric portion32of which an intermediate portion is eccentric with respect to portions of both sides (both-side portions). The driving shaft30is rotatably supported by both side walls12aand12bof the driving-side frame12via bearings in an orientation in which the axial direction matches with the width direction, and is accommodated in the driving-side frame12in such a form.

The support position is located such that the driving shaft30is located below an intermediate portion in the opening portion14cin the frame body14when the driving-side frame12is viewed in the width direction. The driving shaft30is supported by the frame cover16at one end thereof in one end side. Therefore, the driving shaft30is in a state where a portion including the other end is provided in a form of protruding, on the other end side, from an inner wall (inner wall portion)14bof the frame body14in the width direction. The driving shaft30is supported by the inner wall portion of the frame body14at a portion on the driving-side frame12side from the protruding portion. The main shaft5is connected to the other end of the driving shaft30by a coupling member70.

Similar to the driving shaft30, the swing shaft50is formed as a shaft of which a dimension is larger than the dimension of the driving-side frame12in the width direction. Similar to the driving shaft30, the swing shaft50is supported by the both side walls12aand12bof the driving-side frame12via bearings in the orientation parallel to the driving shaft30, and is accommodated in the driving-side frame12. Similar to the driving shaft30, the support position is a position within the range of the opening portion14cin the frame body14when the driving-side frame12is viewed in the width direction, and is a position above the driving shaft30. The swing shaft50is also supported by the frame cover16at one end thereof, a portion including the other end is provided so as to protrude from the inner wall portion14bof the frame body14, and is supported by the inner wall portion14bof the frame body14at the other end side thereof. A locking shaft44that supports the reed42is connected to the other end of the swing shaft50by a coupling member72.

As described above, the swing mechanism60is the crank mechanism and includes a swing arm62which is provided so as not to rotate relative to the swing shaft50, and a connection lever64which is a link for connecting the swing arm62and the eccentric portion32of the driving shall30. In the illustrated example, the swing shaft50and the swing arm62are integrally formed. The connection lever64is relatively rotatably connected to the swing arm62and the driving shaft30(eccentric portion32). In the swing mechanism60, the driving shaft30is rotationally driven and the eccentric portion32is rotationally moved at a position eccentric from a shaft center of both-side portions, and thereby the swing arm62(swing shaft50) connected to the eccentric portion32via the connection lever64is driven to swing. Therefore, in that configuration, a part of the driving shaft30also functions as the swing mechanism60. As described above, the swing shaft50is driven to swing, and thereby the locking shaft44connected to the swing shaft50and the reed42supported by the locking shaft44move to swing, and the beating operation is performed.

In the loom1described above, the loom1includes a driving-force transmission mechanism80that connects the driving shaft30and the driving motor20. Therefore, the driving shaft30connected to the main shaft5is rotationally driven by the driving motor20. The driving-force transmission mechanism80is configured to include a driving-force transmission shaft82connected to the driving motor20and a transmission mechanism84connecting the driving-force transmission shaft82and the driving shaft30. A braking device110included in the loom1to apply a brake to the main shaft5is provided to apply a direct brake to the driving-force transmission shaft82. An opening device120that reciprocates a heddle frame (not illustrated) in a vertical direction uses the driving motor20as a driving source, and is connected to the driving-force transmission shaft82which is connected to the driving motor20. Details of the loom1of the present example are as follows.

The driving-force transmission shaft82is formed as a shaft of which a dimension (length dimension) in the axial direction is larger than the dimension of the driving-side frame12in the width direction and is larger than the length dimension of the driving shaft30. The driving-force transmission shaft82is provided to be supported by the inner wall12bof the driving-side frame12via a bearing on one end side thereof in the orientation parallel to the driving shaft30, and penetrate the outer wall portion14a(outer wall12aof the driving-side frame12) of the frame body14, and the other end thereof is located on the outside of the outer wall portion14a. Therefore, the driving-force transmission shaft82is in a state where a portion between the portion supported by the bearing and the outer wall portion14ais accommodated within the driving-side frame12. However, as described above, although the driving-force transmission shaft82is supported by the inner wall12bon the one end side, the driving-force transmission shaft82also protrudes from the inner wall12bso that the one end is located on the outside of the inner wall12b. The driving-force transmission shaft82provided as described above is connected to the driving shaft30by the transmission mechanism84within the driving-side frame12.

The support position of the driving-force transmission shaft82is a position outside the range of the opening portion14cin the frame body14, and is a position separated downward from the driving shaft30. In the outer wall portion14aof the frame body14, a through hole14dis formed at a position corresponding to the support position to allow the driving-force transmission shaft82to penetrate as described above.

In the present example, the transmission mechanism84is configured as a gear train including two gears accommodated within the driving-side frame12. Specifically, the transmission mechanism84is configured of a driving gear84aattached so as not to rotate relative to the driving-force transmission shaft82, and a driven gear84bthat meshes with the driving gear84aand is attached so as not to rotate relative to the driving shaft30. The position where the driving gear84aand the driven gear84bare attached to each shaft is a position on the inner wall12bside of the driving-side frame12in the width direction from the connection position between the driving shaft30(eccentric portion32) and the swing mechanism60(connection lever64). That is, in the present example, the driving-force transmission shaft82and the driving shaft30are connected at a position on the inner wall12bside of the driving-side frame12in the width direction from the connection position between the driving shaft30and the swing mechanism60.

The driving-force transmission shall82is a driving mechanism90for rotationally driving the driving-force transmission shaft82on the other end side, and is connected to the driving mechanism90including the driving motor20. In addition to the driving motor20, the driving mechanism90includes a driving gear train92that connects the output shaft22of the driving motor20and the driving-force transmission shaft82. The driving mechanism90is configured to have a housing-shaped driving box94as a base, the driving motor20is attached to the outer surface of the driving box94, and the driving gear train92is accommodated within the driving box94.

In the driving box94, the driving motor20is attached to an outer surface94a1of one side wall94aof the pair of side walls94aand94bfacing each other, and the both side walls94aand94bare provided to be parallel to the outer wall12aof the driving-side frame12. The driving box94is provided to overlap the driving-side frame12in the back and forth direction of the loom1. As described above, since the driving-force transmission shaft82protruding from the driving-side frame12is connected to the driving gear train92accommodated within the driving box94, the driving-force transmission shaft82penetrates the other side wall94bof the pair of side walls94aand94bin the driving box94, and the portion of the other end side is located within the driving box94(accommodated in the driving box94). Therefore, a through hole94dthat allows the penetration of the driving-force transmission shaft82is formed on the other side wall94bin the driving box94.

As described above, the driving-force transmission shaft82protruding from the driving-side frame12is supported by one side wall94ain the driving box94via a bearing at the other end. However, the driving box94is provided such that the other side wall94bthrough which the driving-force transmission shaft82penetrates is separated from the driving-side frame12.

The driving motor20is attached to the driving box94by bolts or the like (not illustrated) such that the output shaft22is oriented toward the driving-side frame12side at a position separated upward with respect to the driving-force transmission shaft82supported as described above. A through hole94cis formed on one side wall94ain the driving box94to which the driving motor20is attached to allow the output shaft22of the driving motor20to penetrate at the attachment position. Therefore, as described above, in a state where the driving motor20is attached to the driving box94, the output shaft22extends within the driving box94in the width direction and exists to be parallel to the driving-force transmission shaft82. The output shaft22is connected to a portion of the driving-force transmission shaft82on the portion of the other end side of via the driving gear train92within the driving box94.

Similar to the gear train84connecting the driving shaft30and the driving-force transmission shaft82, the driving gear train92is configured of two gears. Specifically, the driving gear train92is configured of a driving gear92athat is attached so as not to rotate relative to the output shaft22of the driving motor20, and a driven gear92bthat meshes with the driving gear92aand is attached so as not to rotate relative to the driving-force transmission shaft82.

The driving mechanism90includes an opening shaft96to which the opening device120in the loom1is connected, and an opening gear train98that connects the driving-force transmission shaft82and the opening shaft96. The opening shaft96is formed as a shaft having a dimension (length dimension) in an axial direction, which is larger than a dimension of the driving box94in the width direction. The opening shaft96is supported by both side walls94aand94bof the driving box94via bearings in an orientation parallel to the driving-force transmission shaft82at a position spaced downward with respect to the driving-force transmission shaft82. The opening shaft96is provided so that one end thereof protrudes from one side wall94aof the driving box94. The opening shaft96is connected to the opening device120at the protruding one end portion thereof.

The opening shaft96is connected to the driving-force transmission shaft82via the opening gear train98within the driving box94. The opening gear train98is configured of two gears like the driving gear train92. Specifically, the opening gear train98is configured of a driving gear98aattached so as not to rotate relative to the driving-force transmission shaft82, and a driven gear98bthat meshes with the driving gear98aand is attached so as not to rotate relative to the opening shaft96.

The braking device110is an electromagnetic brake and is provided so as to directly apply a brake to the driving-force transmission shaft82. In the present example, the braking device110is provided at a position inside from the inner wall12bof the driving-side frame12in the width direction. The braking device110is mainly configured of a housing-shaped body case110a, and is attached to the inner wall12bof the driving-side frame12in the body case110a. The braking device110includes a braking member110band a braked member110caccommodated in the body case110a, and the braked member110cis disposed to be directly attached to one end (end protruding from the inner wall12b) of the driving-force transmission shaft82.

The braked member110cis a disk-shaped member and is attached so as not to rotate relative to the driving-force transmission shaft82in a state where the driving-force transmission shaft82is inserted through a through hole formed in a boss portion at a center. The braking member110bis urged by an urging member (not illustrated) such as a spring member in the axial direction of the driving-force transmission shaft82to which the braked member110cis attached. In the braking device110, a built-in exciting coil (not illustrated) is put into an excited state (or a non-excited state), so that the braking member110bis configured to be displaced to a braked member110cside against an urging force by the urging member. Thus, in a state where the braking member110bis pressed against the braked member110c, the braking device110applies the brake to the driving-force transmission shaft82, and further applies the brake to the driving shaft30, the driving motor20, and the opening device120connected to the driving-force transmission shaft82.

In the illustrated example, the frame body14has a protruding portion14eformed to protrude from the outer wall portion14atoward the driving box94side around the through hole14din the outer wall portion14a. On the other hand, the driving box94also has a protruding portion94eformed to protrude from the other side wall94btoward the driving-side frame12side around the through hole94din the other side wall94b. The frame body14and the driving box94are connected such that the both protruding portions14eand94eare fitted to each other. In spaces inside the protruding portions14eand94e, oil seals100are provided between inner peripheral surfaces of the protruding portions14eand94e, and the driving-force transmission shaft82.

According to the loom1of the present example configured as described above, during the braking of the loom1(main shaft5), since the brake is directly applied to the driving-force transmission shaft82by the braking device110, the load applied to the transmission mechanism84that connects the driving-force transmission shaft82and the driving shaft30is smaller than that of the device of the related art.

More specifically, the braking device110is actuated, a braking force by the braking device110directly acts on the driving-force transmission shaft82, and the brake is applied to the driving-force transmission shaft82. When the brake is applied to the driving-force transmission shaft82, the brake is applied to the driving shaft30connected to the driving-force transmission shaft82, and the brake is also applied to the driving motor20and the opening device120. The brake of the driving shaft30is performed in a form of the brake of the main shaft5and the beating device40connected to the driving shaft30. For the brake of the driving shaft30(main shaft5and beating device40), as described above, since the driving-force transmission shaft82and driving shaft30are connected via the transmission mechanism84(driving gear84aand driven gear84b), the driving gear84aattached to the driving-force transmission shaft82acts the braking force on the driven gear84battached to the driving shaft30.

When the braking is applied to the driving-force transmission shaft82, an inertia force acts on the driving-force transmission shaft82by the inertia of the driving motor20and the opening device120to which the brake is applied accordingly. Along with this, the braking force that acts on the driven gear84bby the driving gear84abecomes a force having a size weakened by the inertia force of the braking force by the braking device110due to the action of the inertia force. That is, during the braking, in the transmission mechanism84, the driving gear84acauses the braking force of such a size to act on the driven gear84b. On the other hand, when the brake is applied to the driving shaft30, the inertia force acts on the driving shaft30by the main shaft5and the beating device40. The inertia force acts on the driving gear84avia the driven gear84bas a force against the braking force in the transmission mechanism84.

As described above, in a case where the driving-force transmission shaft82and the driving shaft30are connected by a gear train such as the transmission mechanism84, during the braking, the gear (driving gear84a) on the braking side causes the braking force to act on the gear (driven gear84b) on the braked side, and the gear on the braking side receives a force against the braking force from the gear on the braked side. The greater those forces acting in this way, the greater the load is applied to the transmission mechanism84. In the loom, the inertia force (inertia force by the driving motor20and the opening device120) acting on the driving-force transmission shaft82with the brake is generally greater than the inertia force (inertia force by the main shaft5and the opening device120) acting on the driving shaft30. Therefore, if the loom is configured to directly brake the driving-force transmission shaft82having a large inertia force acting during the braking, both the above-mentioned braking force and the force against the braking force become a small force compared to that of the case of the device of the related art. Therefore, the load applied to the transmission mechanism84is smaller than that of the device of the related art, and as a result, the transmission mechanism84is prevented from being damaged as much as possible.

In the above, one embodiment (hereinafter, referred to as “the above example”) of the loom to which the present invention is applied is described. However, the present invention is not limited to the configuration described in the above example, and can be implemented in other embodiments (modified examples) as described below.

(1) Regarding the connection position of the braking device with respect to the driving transmission shaft, in the above example, the connection position is inside the driving-side frame12in the width direction. However, in the present invention, the connection position is not limited to the inside of the driving-side frame, and may be outside. In that case, the braking device may be attached to the outer wall of the driving-side frame or attached to the side wall of the driving box.

(2) Regarding the transmission mechanism that connects the driving shaft and the driving transmission shaft, the transmission mechanism is not limited to the gear train configured of two gears of the driving gear84aand the driven gear84bwhich are accommodated within the driving-side frame12as in the above example. For example, the transmission mechanism may be one that is also configured of the same gear train, or may be a gear train that is configured of three or more gears. The transmission mechanism is not limited to one configured of the gear train, and may be configured to connect a pulley attached to the driving shaft and a pulley attached to the driving-force transmission shaft with a timing belt.

The configuration in which the driving motor and the opening device are connected to the driving-force transmission shaft is not limited to the gear train configured of two gears as in the above example, and as in the case of the transmission mechanism described above, the gear train may be configured of three or more gears, or may be connected by a pulley and a timing belt. As described above, in the configuration in which the driving motor and the opening device are connected to the driving transmission shaft, a configuration may be provided in which one of the driving motor and the opening device is connected to the driving-force transmission shaft via a coupling member or the like.

(3) Regarding the position where the driving shaft and the driving-force transmission shaft are connected by the transmission mechanism, in the above example, the connection position is the inner wall12bside of the driving-side frame12with respect to the eccentric portion32of the driving shaft30in the width direction. However, the connection position may be on the outer wall12aside of the driving-side frame12with respect to the eccentric portion32of the driving shaft30in the width direction.

(4) Regarding the swing mechanism, the above example is an example of the present invention applied to the loom in which the crank mechanism is adopted as the swing mechanism60. In the above example, the swing arm62in the swing mechanism60is integrally formed with the swing shaft50. However, even in the crank mechanism as in the above example, the swing mechanism may be configured such that the swing arm and the swing shaft are formed as separate members, and both are connected so as not to rotate relative to each other. The swing mechanism is not limited to the crank mechanism as in the above example, and may be a cam mechanism. In that case, the shaft to which the cam is attached becomes the driving shaft in the present invention.

Further, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of tine present invention.