SE544226C2 - Device and method for attaching a row unit and agricultural implements comprising such a device - Google Patents

Abstract

This document shows a device for attaching a row unit (2, 2a-2f) to a frame beam (11) of an agricultural implement (1). The device comprises a fastening frame (60), which has a base portion (601), and at least one engaging portion (602a, 602b; 603a, 603b). The engaging portion (602a, 602b; 603a, 603b) is designed to at least partially surround the frame beam (11) or a part thereof and to engage the frame beam (11) by means of at least one abutment surface (6061, 6071) facing the base portion (601). A biasing device, which comprises at least one wedge body (61a, 61b), which is displaceable along a plane (P) of the fastening frame (60) facing the frame beam (11), between an open position and a locking position, so that the wedge body (61a , 61b), in the locked position, provides a locking force between the mounting frame (60) and the frame beam (11), the beam (11) being clamped between the wedge body (61a, 61b) and the abutment surface (6061, 6071). The document also shows an agricultural implement comprising a several such devices as well as a method for mounting a row unit on an agricultural implement.

Description

TECHNICAL FIELD This document relates to a device for attaching a row unit to a support structure, such as a frame beam, in a row structure attachment, sàsom en rambalk.

Background Agricultural implements intended for feeding granular material to land over which the agricultural implement travels, for example seed drills or machines for distributing fertilizers and / or pesticides, may comprise a number of row units.

Each row unit has functionality to open a furrow in the ground, feed material to the furrow and then close the furrow. The loading of granules can be done individually, as in the case of precision seed, or volumetrically. The row unit may comprise a feeding device, for example in the form of a singulation device, as well as a container or buffer for the granular material.

Each row unit can usually operate independently of the other row units. Optionally, the feed rate of the row units can be controlled individually, for example to compensate for speed variations between row unit and ground, as occurs when cornering.

An agricultural implement can comprise several row units. For example, on the market, seed drills can have between 4 and 24 row units.

It is desirable to be able to adjust the agricultural implement, so that different spacing can be used when sowing different crops.

For this purpose, it is known to arrange a number of row units along the transverse frame beam of the agricultural implement. Adjustment of row spacing can be achieved by displacing the row units along the frame beam. In the desired position, the row unit is usually read relative to the frame beam by means of a clamping joint, which is usually actuated by means of some form of 2 bolt. Examples of such dressings are shown in US2015150184 AA and US2018146609AA.

There is a need to provide an improved attachment of the row unit to the frame beam, and in particular a fastening which makes it easier for one-user to adjust the row spacing of the agricultural implement.

SUMMARY It is thus an object to provide a device for attaching a row unit to a frame beam, which makes it easier for a user to set the area distance. A special purpose is to provide a safe and reliable device, which reduces the time it takes to change the agricultural implement.

The invention is defined by the appended independent claims. Embodiments appear from the dependent claims, from the following description and from the drawings.

According to a first aspect, a device for fastening a single-row unit to a frame beam of an agricultural implement is provided, comprising a fastening frame, which has a base portion, and at least one engaging portion. The engaging portion is designed to at least partially surround the frame beam or a part thereof and to engage with the frame beam by means of at least one abutment surface facing the base portion. A biasing device comprising at least one wedge body slidable along a plane of the mounting frame facing the frame beam between an open position and a reading position so that the wedge body, in the reading position, provides an expanding reading force between the mounting frame and the frame beam, the frame beam being clamped between the wedge body and the contact surface.

A "wedge body" is a body that is wedge-shaped, or has a wedge-shaped portion. The wedge body preferably has two flat surfaces, which form an acute angle relative to each other. The angle can be selected to be small enough to allow self-locking of the friction joint. Alternatively, the angle can be selected enlarged to allow self-locking, whereby the wedge bodies can instead be read with the aid of the crank body or its lever. Preferably the angle is in the order of 1-30 degrees, most preferably 5-15 degrees. The wedge body may be formed as a straight prism, with a constant cross-section at at least its wedge-shaped portion.

By "surrounding the frame beam or a part thereof" is meant that the fastening portion runs completely or partially around the cross section of the beam. Preferably, this can mean that the engaging portion allows such an engagement with the beam, that the fastening frame can only be removed by a displacement of the fastening frame along the longitudinal direction of the beam. However, the engaging portion must be designed so that there is sufficient clearance between the beam and the engaging frame so that displacement along the beam is facilitated.

For example, the engaging portion can completely enclose the beam, ie stretch sigrunnally the entire cross-sectional area of the beam, just like a U-shaped cramp.

Alternatively, the engaging portion may extend around a portion of the beam cross-sectional area, to engage with an opposite side of the beam, with a single heel of the beam or with a recess in the beam.

The abutment surface can be local, ie formed only over a part of the width of the fastening frame, such as over less than 25 ° />, or less than 10 ° /> of the width of the fastening frame.

Alternatively, the abutment surface may extend over a substantial portion of the width of the mounting frame, such as at least 75 ° /> of the mounting frame width, or at least 90 ° /> of the mounting frame width.

By utilizing a wedge body which acts between the fastening frame and the frame beam, a very large clamping force can be achieved. The mounting frame may have two engaging portions extending from respective ends of the base portion. The engaging portions may extend substantially perpendicularly from the base portion, and preferably beyond the plane. The engaging portions may be spaced apart in the vertical and / or horizontal directions.

An abutment portion can extend between the engaging portions.

The abutment portion may be formed by the base portion or a leg portion.

The biasing device may comprise a crank body and a link, the link being rotatably connected to an eccentric portion of the crank body and to the 4 wedge body, so that the displaceability of the wedge body is controllable by means of a single rotation of the crank body.

With the aid of the crank body and the link, the displacement of the wedge plug, which can be substantially linear, can be controlled by means of a rotational movement.

The device may further comprise a lever integrated with the crank body or a lever bracket.

By integrating a lever or a lever bracket with the crank body, it is possible to provide a sufficiently large torque on the crank body so that the wedge body can be brought into or out of engagement.

The crank body can be rotatably arranged relative to the base portion.

The crank body can be rotatably attached to the base portion by means of a shaft which is arranged in the heel of the crank body and the base portion.

Alternatively, one shaft can be integrated with the base portion or with the crank body and arranged in heel in the other of the crank body and the base portion.

The crank body can be displaceable relative to the base portion.

By making the crank body displaceable relative to the base portion, and particularly displaceable in a plane parallel to the base portion, it is possible to ensure that the same force is applied to more than one wedge body. Because the crank body is floatingly mounted against the base portion, the crank body can move, since the wedge bodies act with each other as abutment instead of with the crank body as abutment for either wedge body.

The crank body can be mounted by means of an elongate heel formed in the base portion.

The link can be slidably connected to the wedge body.

The fact that the link is "displaceably connected" means that the attachment of the link to the wedge body is displaceable. This can be achieved by either the wedge body or the link having an elongate heel in which a pin is arranged.

The device may further comprise an adjusting device, for adjusting the displaceability of the deflector relative to the wedge body.

For example, the displaceability of the link relative to the wedge body can be limited, to ensure that the wedge body does not engage too late.

With such adjusting devices on at least one wedge body, it is possible to balance the engagement of the wedge bodies.

The biasing device may comprise at least two wedge bodies which are displaceable in different, preferably opposite, directions.

The wedge bodies can be displaceable in substantially opposite directions.

Preferably, the wedge bodies are displaceable so that they move in substantially opposite directions, i.e. both are pushed out when the biasing device is actuated and both are retracted when the biasing device is released.

This is especially preferred in connection with a crank body being used to force the movement of several wedge bodies. Alternatively, a crank body can be provided for each wedge body.

It is conceivable to provide more than two wedge bodies, for example three-wedge bodies which are displaceable in three directions which deviate 120 degrees from each other. In such a system, the crank body can be mounted floating in more than one direction, for example because its mounting hole is circular, but larger than its axis. The mounting frame can have a ramp surface cooperating with the wedge body.

The film surface may have an angle relative to the surface of the frame beam, which is substantially the same as the wedge angle of the wedge body.

The contact surface can have a friction-reducing coating.

By providing the abutment surface with a friction-reducing coating, displacement of the row unit along the beam is facilitated. In addition, the risk of damage to the surface layer of the beam, which can be painted, is reduced.

The wedge body may have a first surface which is substantially parallel to the surface of the frame beam facing the base portion and a second surface which constitutes a single-frame surface.

According to a second aspect, an agricultural implement is provided, comprising a frame and a plurality of row units, the frame comprising a transverse frame beam, and the row units being attached to the frame beam by means of a respective device according to any one of the preceding claims. The frame beam may, on at least one surface portion against which abutment between the mounting frame and the frame beam is located, have a friction-reducing coating.

The bearing can be present when the row units are in a fixed condition, or during displacement of the row unit relative to the frame beam.

According to a third aspect, a method of attaching a single row unit to a frame beam of an agricultural implement is provided, comprising arranging a single mounting frame in at least partially enclosing engagement with the frame beam, arranging a wedge body in engagement between the mounting frame and the frame beam, and displacing the wedge body between and the frame beam.

An eccentric portion of a crank body may be connected to the wedge body by a link, the displacement of the wedge body being effected by turning the crank body.

Brief Description of the Drawings Fig. 1 shows a perspective view of an agricultural implement in the form of a precision seed drill.

Fig. 2 shows a perspective view of a part of an agricultural implement, comprising a row unit which is attached to a frame beam.

Fig. 3 shows a perspective view of a row unit.

Fig. 4 shows an exploded view of a fastening device.

Fig. 5 shows a sectional view of the fastening device, seen in a vertical plane which is perpendicular to the frame beam.

Fig. 6 shows a perspective view of the fastening device in the open condition.

Fig. 7 shows a perspective view of the fastening device in read condition.

Fig. 8a shows a sectional view of the fastening device, seen in a horizontal plane, and in the open condition.

Fig. 8b shows a sectional view of the fastening device, seen in a vertical plane, which is parallel to the frame beam, and in the open condition.

Fig. 9a shows a sectional view of the fastening device, seen in a horizontal plane, and in a read condition. Fig. 9b shows a sectional view of the fastening device, seen in a vertical plane, which is parallel to the frame beam, and in the locked condition. Fig. 10 shows a plan view of the fastening frame, seen from the front.

Detailed description Fig. 1 shows a perspective view of an agricultural implement 1 in the form of a precision seed drill.

The agricultural implement 1 comprises a number, in this example six, output units 2a-2f, also called "row units", which are arranged side by side and suspended on a transverse beam 11, which forms part of a frame, which is supported by two wheels 3a , 3b. The agricultural implement 1 is, by means of a fastening member 5 arranged at a free end of a longitudinal drawbar 10, arranged to be coupled to a towing vehicle, such as a tractor, and intended to be driven in a one-way direction indicated by the arrow F.

Each of the discharge units 2a-2f has a sowing device, which is arranged to, during the movement of the agricultural implement 1 over the soil to be sown, form a sap in the direction of travel of the agricultural implement 1, discharge material, in the case illustrated seed, and possibly also fertilizer and / or pesticides, to the saffron, after which it is sealed. In the example shown, each output unit 2a-2f has its own drive device (not shown), which may comprise an electric motor and a local control unit, which regulates the drive device and can function as an interface to a central control unit.

The discharge units 2a-2f can be movably fastened to the frame 10, 11 of the agricultural implement. In the example shown, the seed drill is thus a so-called precision seed drill, ie a seed drill which singles out the granules, such as seeds, to be distributed, and places them one by one at a certain distance in the direction of travel.

It will be appreciated that the invention may also be applied to other types of seed drills, such as volumetric feed drills, and in particular to such drills where the row units operate individually or in groups with respect to the amount of material discharged per unit length.

In addition, the invention can be applied to machines for distributing pesticides and / or fertilizers, in solid or liquid form, even provided that the discharge nozzles are individually or in groups controllable. Fig. 2 shows a perspective view of a row unit 2, which is fastened to transverse frame beam 11 by means of a fastening device 6, seen obliquely from behind. A parallel linkage 4 extends between the fastening device and the row unit 2.

Fig. 3 shows the row unit 2 with the parallel linkage 4 and the fastening device 6, seen obliquely from the front. Fig. 4 shows an exploded view of the fastening device 6. The fastening device 6 comprises a fastening frame 60, which comprises a base portion 601, which may be substantially flat and formed by a plate of sufficient thickness; a pair of leg portions 605a, 605b, which are also substantially flat and may be formed by respective plates of sufficient thickness; and a pair of abutment portions 606, 607, which may also be formed of respective plates of sufficient thickness.

Plate thickness for fastening portions and base portion can be in the order of 8-20 mm, preferably 9-15 mm. For the abutment portions, the plate thickness can be slightly smaller, for example 5-10 mm.

The leg portions 605a, 605b may be integrated, such as permanently joined, with the base portion 601 by means of a bolt / screw, weld or solder. Alternatively, the leg portions 605a, 605b and the base portion 601 may be formed in one piece, for example as a molded article.

The abutment portions 606, 607 may be joined to the leg portions 605a, 605b by welding or soldering.

Alternatively, the base portion 601 and one, or both, of the abutment portions 606, 607 may be formed of one and the same plate, which is bent substantially C-shape.

The base portion 601 may have a through heel 604 for mounting the biasing device. The tail can be elongated. In the example 9 shown, the hole 604 is elongated in a horizontal direction. A sleeve 66 and a bolt 67 can be used for said mounting of the biasing device.

The leg portions 605a, 605b have respective engaging portions 602a, 602b; 603a, 603b, which are designed to enclose at least a part of the frame beam 11. In the example shown, the engaging portions are specially designed to partially enclose a beam with "hourglass-shaped" cross-sections, as shown in Fig. 5, i.e. a beam whose cross-section has lugs.

The leg portions 605a, 605b may have a beam interface, in the form of one or a plurality of surface portions which are located in one and the same plane P and which face one and the same surface portion 110 of the beam 11. The engaging portions 602a, 602b; 603a, 603b extend beyond the plane P, and have abutment surfaces facing the plane P.

Recesses 608a, 608b are formed in the leg portions 605a, 605b. The recesses can extend perpendicularly inwards from the plane P. At the bottom of the recesses the respective ramp surfaces 610a, 610b can be present. The ramp surfaces are thus spaced from the plane P to the extent that they are retracted from the plane P. Adjacent to the recesses 608a, 608b, horizontal support plates 609a, 609b can be arranged. The support plates can help control the movement of the wedge bodies.

The biasing device further comprises a crank arrangement, comprising a crank body 62, which is rotatably mounted relative to the base portion 601 via a mounting hole 621. The crank body 62 may have a pair of eccentric holes 622a, 622b and a lever 623.

The wedge bodies 61a, 61b have an engaging portion 612 with a wedge surface 6121 and a flat surface 6122; and a coupling portion 613, which may be the recessed relative engagement portion, to leave space for the links 63a, 63b. The wedge body neck is made of metal, preferably steel.

The wedge bodies 61 a, 61 b can be connected to the crank body 62 via links 63a, 63b. Each link may be pivotally connected to the wedge body 61a, 61b and to the crank body 62, respectively.

The links can be designed as elongated flat plate parts with attachment halves and respective ends.

The wedge bodies 61 a, 61 b may be movable in directions parallel to the plane P. The expanding force produced by the ramp surface of the wedge bodies may have a largest force component in a direction perpendicular to the plane P.

The links 63a, 63b and the pins 64 may be dimensioned to allow certain play, especially in a horizontal plane, so that the wedge bodies are allowed to be displaced laterally slightly when they engage with the ramp surfaces 610a, 610b.

The hole 6133 in the wedge body may be elongate, to allow the pin 64 to be displaced slightly relative to the wedge body.

The beam 11 shown in Fig. 5 has a cross-section, which means that it is shaped to have a pair of opposite sides with recessed or countersunk surface portions 111 and a pair of opposite surface portions 110 which are flat.

A beam with an hourglass-shaped cross-section can be formed by rolling a beam blank with a rectangular or square cross-section in a manner known per se. Such hollow and hourglass-shaped beam profiles find special application when it is desirable to be able to use / or when it is desirable to be able to lower, for example, bolt heads or other fastening elements so that they do not interfere with, for example, cramps or mounting devices of this type extending around all or part of the beam, thereby providing greater freedom to mount equipment such as row units along the length of the beam.

The recessed sides 111 are delimited by ramp surfaces 112, 113, the normal directions of which form an angle which is 100-170 degrees relative to the normal directions of the planar sides, preferably 110-160 degrees.

As shown in Fig. 5, engaging surfaces 6061, 6071 of the abutment portions 606, 607 and / or of the engaging portions 602a, 602b, 603a, 603b engage the frame surfaces 112, 113 of the frame beam 11.

The base portion 601 may be substantially parallel to a front surface 110 of the hose frame beam 11. As shown in Fig. 5, the wedge portions act between the mounting frame 60 and the front surface 110 of the beam, and more particularly between the frame surfaces 610a, 610bhos of the mounting frame 60 and the front surface 110.

It will be appreciated that the engaging portions may be designed to completely or partially enclose a beam of circular or square cross-section; or to engage with, for example, a pair of flanges of an l-beam. Fig. 6 shows the fastening device in mounted and open condition. The crank body 62 is rotatably mounted relative to the base portion 601. The links 63a, 63b connect eccentric heels 622a, 622b of the crank body 62 to the wedge bodies 61a, 61b. As shown in Fig. 6, the crank body 62 is in a condition where the center centers 622a, 622b are laterally retracted, and thus the links 63a, 63b and the wedge bodies 61a, 61b are also laterally retracted.

The corresponding view is shown in Figs. 8a and 8b, where it can be seen that the wedge bodies 61a, 61b in this state have little, or no, engagement with the ramp surfaces 610a, 610b. As a result, little or no expanding force is generated between the fastening frame 60 and the beam 11. In Figs. 7 and 9a-9b the fastening device is shown in the read condition. As can be seen here, the crank body 62 is in a state where the eccentric heels 622a, 622b are in their laterally extreme extreme positions, and thus the wedge bodies 61a, 61b are also in their laterally extreme extremes.

The corresponding view is shown in Figs. 9a and 9b, where it can be seen that the wedge bodies 61a, 61b in this state have extensive, or complete, engagement with the frame surfaces 610a, 610b. This generates a strong expanding force between the mounting frame 60 and the beam 11. As the abutment surfaces 6061, 6071 engage the corresponding surfaces 112, 113 of the beam 11 as a counterweight, the beam 11 will, in the last position, be clamped between the abutment surfaces 6061, 6071 and the wedge bodies. 61a, 61 b.

In Fig. 10, the horizontally elongated heel 604 is shown in the base portion 601. Because the heel is elongated, the crank body 62 is limited slidably relative to the base portion 601, so that the horizontal position of the crank body relative to the base portion 601 can be determined by the grooves of the wedge bodies 61a, 61b. Thus, the entire horizontal force will act 12 between the wedge bodies, via the links and the crank body, instead of acting between the wedge bodies and the crank body 62. It is thus possible to ensure that both wedge bodies engage fully, as the risk of the single wedge body engaging before the other, then reduced. Pilot-like effect can be achieved by means of an elongated, or slightly oversized, heel in the crank body 62.

This therefore provides an opportunity to calibrate the fastening device 6 in order to be able to compensate for manufacturing tolerances.

As mentioned above, the wedge bodies may have an engaging hole 6133, which is elongate, in which the pin 64 connecting the wedge body 61a, 61b to the link 63a, 63b is received.

In addition, an adjusting screw 614 may be provided in the wedge body 61a, 61b, to limit the movement of the pin along the length of the hole 6133.

By screwing in the adjusting screw 614, it is possible to set at which positions the pin 64 should start pressing on the wedge body 61a, 61b. For example, the adjusting screw 614 can be screwed all the way in to read the pin at its innermost position.

This thus provides an additional possibility to calibrate the fastening device 6 in order to be able to compensate for manufacturing tolerances. In the example shown, the wedge bodies are displaced in horizontal directions, parallel to the longitudinal direction of the frame beam. It will be appreciated that the wedge bodies may instead be displaceable in other directions, which are preferably parallel to the counter-row unit facing the surface of the frame beam, but which do not have to be horizontal. For example, the wedge bodies can be displaced in vertical directions. Installation of a row unit with fastening device 6 as shown herein can be done as follows.

The biasing device is placed in its open position, ie the co-wedge bodies 61a, 61b retracted.

Thereafter, the row unit is threaded onto the frame beam along its longitudinal direction, the co-engaging portions 602a, 602b; 603a, 603b in engagement with the lugs of the dentim glass-shaped beam. Then the row unit 2 is moved to the desired position laterally. When the desired position is reached, the biasing device is actuated, for example by rotating the lever 623 or an extension thereof (not shown) so that the crank body 62 is rotated about the axis 66, 67, the links 63a, 63b push the wedge bodies 61a, 61b so that they are extended . The wedge body frame surfaces 6121 then engage the mounting frame frame surfaces 610a, 610b, so that the wedge body surfaces 6122 are pressed against the surface 110 of the beam 2 facing the row unit 2.

When sufficient attachment force is achieved, the lever 623 can be read relative to the attachment frame, to prevent the biasing device from being inadvertently released, for example due to vibrations.

When adjusting the positions of the row units, the biasing device can be released, the row unit moved to the desired new position, after which the biasing device is actuated again.

A friction-reducing coating 615 may be provided, either on the abutment surface 6061, 6071, or on the surface portion or portions of the frame beam 11 against which any portion of the mounting frame 60 will abut, or on bed abutment surfaces and the frame beam.

Claims (18)

1. Device for attaching a row unit (2, 2a-2f) to a frame beam (11) of a utility tool (1), comprising: an attachment frame (60), which has a base part (601), and at least one engagement part (602a, 602b; 603a, 603b), wherein the engaging part (602a, 602b; 603a, 603b) is designed to at least partially surround the frame beam (11) or a part thereof and to engage with the frame beam (11) by means of at least one against the base part (601) facing surface ( 6061, 6071), characterized by a biasing device, which comprises at least one wedge body (61a, 61b), which is displaceable along a plane (P) facing the frame beam (11) of the attachment frame (60), between an open position and an read position, say that the wedge body (61a, 61b), in the read position, produces an expanding reading force between the attachment frame (60) and the frame beam (11), whereby the frame beam (11) is clamped between the wedge body (61a, 61b) and the abutment surface (6061, 6071). 2. Device according to claim 1, wherein the attachment frame has two engagement portions (602a, 602b; 603a, 603b), extending from respective ends of the base portion (601). 3. Device according to claim 2, wherein an abutment portion (606, 607) extends between the engagement portions (602a, 602b; 603a, 603b). 4. Device according to any of claims 1-3, wherein the biasing device comprises a crank body (62) and a link (63a, 63b), wherein the link is rotatably connected to an eccentric portion (622a, 622b) of the crank body (62) and to the wedge body (61a, 61b), say that the displaceability of the wedge body (61a, 61b) is controllable by means of a rotation of the crank body (62). 5. Device according to claim 4, further comprising a lever arm (623) or lever bracket integrated with the crank body (62). 6. Device according to claim 4 or 5, wherein the crank body (62) is rotatably arranged relative to the base part (601). 7. Device according to claim 6, wherein the crank body (62) is displaceable relative to the base part (601). 8. Device according to claim 7, wherein the crank body (62) is mounted by means of an elongated hole (604) formed in the base part (601). 9. Device according to any of claims 4-8, wherein the link (63a, 63b) is displaceably connected to the wedge body (61a, 61b). 10.(614), for setting the displaceability of the link relative to the wedge body. Device according to claim 9, further comprising an adjustment device 11. Device according to one of the preceding claims, wherein the biasing device comprises at least two wedge bodies (61a, 61b) which are displaceable in different, preferably opposite, directions. 12. The frame (60) has a ramp surface (610a, 610b) cooperating with the wedge body (61a, 61b). Device according to any of the preceding requirements, wherein attachment 13.the contact surface (6061, 6071) has a friction-reducing coating. Device according to any of the preceding claims, whereby 14. (61a, 61b) has a first surface (6122) which is substantially parallel to a counter Device according to one of the preceding claims, wherein the wedge body 16 base portion facing surface of the frame beam and a second surface (6121) which constitutes a frame pyta. 15. Agricultural implements, comprising a frame and a plurality of row units, wherein the frame comprises a transverse frame beam (11), and wherein the row units (2, 2a-2f) are attached to the frame beam (11) by means of a respective device according to one of the preceding claims. 16. Agricultural implements according to claim 15, wherein the frame beam, on at least one surface against which there is contact between the attachment frame and the frame beam, has a friction-reducing coating. 17. Method for attaching a row unit (2, 2a-2f) to a single-frame beam of an agricultural implement, comprising: arranging an attachment frame (60) in at least partially enclosing engagement with the frame beam (11), arranging a wedge body (61a, 61b) in engagement between the attachment frame (60) and the frame beam (11), and displacing the wedge body (61a, 61b) to produce an expanding force between the attachment frame (60) and the frame beam (11). 18. Method according to claim 17, wherein an eccentric portion (622a, 622b) of a crank body (62) is connected to the wedge body (61a, 61b) via a link (63a, 63b), and wherein the displacement of the wedge body (61a, 61b) is accomplished by to turn the crank body (62).