JP6832841B2 - Work vehicle - Google Patents

Description

The present invention relates to a work vehicle suitable for traveling on an uneven road surface.

Conventionally, four traveling wheels are supported on the vehicle body via an articulated link mechanism having two joints and can be flexed and extended, and each joint is provided with an electric motor and a reduction gear mechanism. In some cases, the articulated link mechanism can be flexed and extended by the driving force of a plurality of electric motors (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 9-142347

The wheel support structure in the conventional configuration makes it possible to maintain the vehicle body in an appropriate posture while bending and stretching the link mechanism even if the traveling road surface is uneven. Therefore, it is conceivable to apply such a wheel support structure to an agricultural work vehicle traveling on a work site having an uneven traveling road surface.

However, in the above-mentioned conventional configuration, each of the plurality of joints is provided with an electric motor for driving, a reduction gear mechanism, and the like, which has a disadvantage that the driving structure becomes complicated and the cost increases.

Therefore, there has been a demand for a work vehicle capable of maintaining the vehicle body in an appropriate posture even in a work place having many irregularities while being able to simplify the drive structure.

The characteristic configuration of the work vehicle according to the present invention is
With the vehicle body
A plurality of traveling devices located on the left and right sides of the vehicle body, respectively, and
A plurality of articulated link mechanisms in which a plurality of links are pivotally connected so as to have at least two or more joints, and the traveling device is supported on the vehicle body so as to be able to move up and down separately.
A drive operating means capable of changing the posture of the articulated link mechanism is provided.
The first link, which is located closest to the vehicle body among the plurality of links, is swingably supported around the horizontal axis with the main body side connecting point as a fulcrum.
A manually operated position fixing means capable of selectively fixing the first link at any of a plurality of preset swing switching positions is provided.
The position fixing means includes a vertical position in which the first link is in a substantially vertical posture, an inward swing position in which the first link swings inward in the front-rear direction of the vehicle body with respect to the vertical position, and a vertical direction. It is configured so that the position can be fixed at each of the outward swinging position that swings outward in the front-rear direction of the vehicle body with respect to the position.
The drive operating means is to change the posture of a link other than the first link among the plurality of links.

According to the present invention, a plurality of traveling devices are supported by an articulated link mechanism so as to be vertically movable with respect to the vehicle body. By changing the posture of the articulated link mechanism by the drive operating means, the height (relative height) of each of the plurality of traveling devices with respect to the vehicle body can be changed. That is, since the heights of the traveling devices provided on the left and right sides of the vehicle body can be changed, the plurality of traveling devices stably support the ground even when traveling on uneven ground. However, it is possible to drive the vehicle while maintaining the vehicle body in an appropriate posture.

The first link among the plurality of links can be switched to a plurality of swing switching positions by swinging around the horizontal axis with the main body side connecting point as a fulcrum, and the first link can be manually switched to any position. It can be fixed by an operation-type position fixing means. The posture of the links other than the first link can be changed by the driving operation means.

For example, the position of the first link is switched to a position suitable for the work and fixed according to the difference in the type of work, and the posture of the other link is switched by the drive operation means to bring the vehicle body to the proper posture. It becomes possible to maintain and run. As a result, the drive operating means can simplify the drive structure without using a device for changing the posture of the first link, while maintaining the vehicle body in a posture suitable for work. It becomes possible to work and run.

Therefore, while it is possible to simplify the drive structure, it is possible to carry out the work while maintaining the vehicle body in an appropriate posture even in a work place having many irregularities.

In the present invention, in the articulated link mechanism, as the other link, one end is swingably supported by the other end of the first link around the horizontal axis, and the traveling device is supported at the other end. It is preferable to have a second link to support.

According to this configuration, an articulated link mechanism is configured by the first link and the second link, and the second link is rocked while the first link is switched to a swing switching position suitable for work. Therefore, the traveling device can be supported up and down with respect to the vehicle body. Since the drive operating means has a configuration in which only one of the two links is operated to change the posture, the drive configuration becomes simple.

In the present invention, it is preferable that the drive operating means is a hydraulic cylinder.

According to this configuration, the attitude change operation of the articulated link mechanism is performed by the hydraulic cylinder, and the hydraulic cylinder is invaded by fine dust, moisture, etc., as compared with the configuration in which the electric motor and the gear mechanism are combined. Even if there is, there is little possibility that it will be adversely affected and cause malfunction.

In the present invention, the articulated link mechanism is supported by the vehicle body so as to be reorientable around the vertical axis core.
It is preferable that a hydraulic cylinder for turning operation for changing the direction of the articulated link mechanism is provided.

According to this configuration, by changing the orientation of the articulated link mechanism around the vertical axis core, the left-right orientation of the traveling device with respect to the vehicle body can be changed. When turning to the left or right, by changing the direction of the traveling device in the turning direction, it is possible to drive the traveling device without applying an excessive lateral force to the traveling device.

It is an overall side view of a work vehicle. It is an overall plan view of a work vehicle. It is a top view of the refraction link mechanism. It is a side view of the refraction link mechanism. It is a front view which shows the attachment state of the refraction link mechanism in the removed state. It is a front view which shows the mounting state of the refraction link mechanism in the mounted state. It is a top view which shows the left-turning state by a turning mechanism. It is a top view which shows the right-handed turning state by a turning mechanism. It is explanatory drawing of the state which the 1st link is in the vertical position. It is explanatory drawing of the state in which the 1st link is in the inward swing position. It is explanatory drawing of the state which the 1st link is in the outward swing position. It is explanatory drawing of the four-wheel running state. It is explanatory drawing of the free movement state. It is a side view of the slope running state. It is a front view of the straddling running state.

Hereinafter, embodiments of the work vehicle according to the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the work vehicle includes a substantially rectangular frame-shaped vehicle body 1 that supports the entire vehicle, a plurality of (specifically, four) hydraulically driven traveling devices 2, and a plurality of hydraulically driven traveling devices 2. A plurality of auxiliary wheels 3 provided corresponding to each of the traveling devices 2, and a refraction link mechanism 4 as a plurality of articulated link mechanisms for supporting the plurality of traveling devices 2 on the vehicle body 1 so as to be freely repositionable. A hydraulically operated drive operating means 5 capable of changing and operating the refraction link mechanism 4 and a hydraulic oil supply device 6 as a hydraulic source for supplying hydraulic oil are provided. The drive operating means 5 is composed of a hydraulic cylinder 26.

Each of the four traveling devices 2 includes a drive wheel 7 rotatably supported around the horizontal shaft core, and a hydraulic motor 9 provided at a shaft support of the drive wheel 7. Each traveling device 2 can rotate and drive the drive wheels 7 separately by operating the hydraulic motor 9.

In this embodiment, when defining the front-rear direction of the vehicle body, it is defined along the vehicle body traveling direction, and when defining the left-right direction of the vehicle body, the left and right are defined in the state of being viewed in the vehicle traveling direction. That is, the direction indicated by the reference numeral (A) in FIG. 1 is the vehicle body front-rear direction, and the direction indicated by the reference numeral (B) in FIG. 2 is the vehicle body left-right direction.

The vehicle body 1 includes a rectangular frame-shaped support frame 10 that surrounds the entire circumference of the vehicle body 1 and supports the entire circumference. The hydraulic oil supply device 6 is housed and supported inside the vehicle body 1. Although not described in detail, the hydraulic oil supply device 6 includes a hydraulic pump driven by an engine mounted on a vehicle to deliver hydraulic oil, a plurality of hydraulic cylinders 26, and a hydraulic oil supply / discharge operation to a plurality of hydraulic motors 9. It is equipped with a hydraulic control unit that controls the flow rate, a hydraulic oil tank that stores hydraulic oil, and the like.

The vehicle body 1 is provided with a control device 11 that controls the operation of the hydraulic oil supply device 6. Although the control operation of the control device 11 is not described in detail, the flood control is based on the command information input by a manual input device (for example, a remote controller or the like) (not shown) or the command information set and stored in advance. Controls the operation of the control unit.

Next, a support structure for supporting the traveling device 2 on the vehicle body 1 will be described.
Each of the four traveling devices 2 is supported by the refraction link mechanism 4 so as to be vertically movable with respect to the vehicle body 1. The refraction link mechanism 4 is supported by the vehicle body 1 so that the direction can be changed around the vertical axis core by the turning mechanism 12.

As shown in FIG. 2, the refraction link mechanism 4 is swingably supported by the support frame 10 around the vertical axis core Y via the swivel mechanism 12. The swivel mechanism 12 is connected to the support frame 10 and swingably supports the refraction link mechanism 4 on the vehicle body side (see FIGS. 3 and 4) and the refraction link mechanism 4 for swiveling operation. It is provided with a hydraulic cylinder 14 (hereinafter, referred to as a swivel cylinder).

As shown in FIGS. 3 to 6, the vehicle body side support portion 13 is sandwiched from the lateral side to a pair of upper and lower square tubular front-rear facing frame bodies 15 provided at the lateral side portion of the support frame 10. The connecting member 16 that is fitted and engaged in the state and is detachably bolted, the outer side pivot bracket 17 located at the outer side portion of the connecting member 16 in the vehicle body front-rear direction, and the vehicle body front and rear of the connecting member 16. An inner pivot bracket 18 located at a location on the inner side in the direction and a vertical rotation support shaft 19 supported by the outer pivot bracket 17 are provided, and the axis Y of the rotation support shaft 19 is provided. The refraction link mechanism 4 is rotatably supported around it.

The refraction link mechanism 4 has a base end portion 20 supported by the vehicle body side support portion 13 rotatably around the vertical axis core Y in a state where the vertical position is fixed, and one end portion of the base end portion 20. A first link 21 swingably supported around the horizontal axis X1 at the bottom, and one end swingably supported around the horizontal axis X2 at the other end of the first link 21 and at the other end. It is provided with a second link 22 on which the traveling device 2 is supported. That is, the first link 21 located on the side closest to the vehicle body 1 of the two links 21 and 22 in the refraction link mechanism 4 swings with the main body side connecting point (lower part of the base end portion 20) as a fulcrum. The second link 22 is movably supported, and the second link 22 is swingably supported with the connection point with the first link 21 as a fulcrum.

To add an explanation, the base end portion 20 is provided in a rectangular frame shape in a plan view, and is rotatable around the vertical axis core Y via the rotary support shaft 19 at a portion deviated inward in the width direction of the vehicle body. It is supported by the outer side pivot bracket 17 of the vehicle body side support portion 13. One end of the swivel cylinder 14 is rotatably connected to the inner pivot bracket 18, and the other end is laterally displaced with respect to the rotary support shaft 19 at the base end 20. It is rotatably connected.

A support shaft 23 provided on one end side of the first link 21 is rotatably erected and supported over both left and right sides of the base end portion 20, and the first link 21 is a support shaft with respect to the lower portion of the base end portion 20. It is rotatably connected around the axis of 23. As shown in FIG. 4, a proximal end side arm portion 21b extending diagonally upward and outward when the first link 21 is in the vertical posture is integrally formed at the proximal end side portion of the first link 21. Has been done.

As shown in FIG. 3, the second link 22 includes a pair of left and right strip-shaped plate bodies 22a and 22b, and is formed in a bifurcated shape in a plan view. A pair of plate bodies 22a and 22b are spaced apart from each other at the connection points of the second link 22 with respect to the first link 21. A connecting support shaft 24 for connecting to the first link 21 is rotatably supported in a region sandwiched between the pair of plate bodies 22a and 22b. The traveling device 2 is supported at the swing-side end of the second link 22 opposite to the connection point with respect to the first link 21.

A swing position adjusting unit 25 as a manually operated position fixing means capable of fixing the first link 21 at a plurality of swing switching positions set in advance to each of the four refraction link mechanisms 4, and a first A hydraulic cylinder 26 as a drive operating means 5 capable of changing the swinging posture of the second link 22 with respect to the one link 21 is provided. The hydraulic cylinders 26 are arranged so as to be lined up in the vicinity of the first link 21. The first link 21 and the hydraulic cylinder 26 are arranged so as to be located between the pair of plate bodies 22a and 22b of the second link 22 in a plan view.

The swing position adjusting unit 25 will be described.
The swing position adjusting unit 25 swings the first link 21 in a vertically oriented position (see FIG. 10) in a substantially vertical posture and a set amount of swinging inward in the front-rear direction of the vehicle body with respect to the vertical position. Positions can be fixed at each of the orientation swing position (see FIG. 9) and the outward swing position (see FIG. 11) that swings a set amount toward the outward side in the front-rear direction of the vehicle body with respect to the vertical position. It is configured in. To add an explanation, a locking action portion 27 is integrally formed with the first link 21, and an insertion hole 28 is formed in a state of being inserted into the locking action portion 27 in the left-right direction.

The regulation member 29 is provided so as to overlap the position where the insertion hole 28 of the first link 21 passes in a side view. The regulating member 29 is integrally connected and fixed to the base end portion 20 of the refraction link mechanism 4. When the first link 21 is switched to the vertical position, the inward swing position, and the outward swing position, the insertion hole 28 formed in the first link 21 faces the regulating member 29. Engagement holes 30 for position regulation, which are inserted in the left-right direction, are formed at each location. Then, in a state where the first link 21 is switched to any of the vertical position, the inward swing position, and the outward swing position, the engagement hole 30 of the regulation member 29 and the insertion hole 28 of the first link 21 By inserting and inserting the locking rod 31 over the above, the relative position of the first link 21 with respect to the vehicle body 1 can be fixed.

When the work vehicle travels on a flat ground, such as when traveling on a ridge or in a field, the first link 21 is switched to a vertical position as shown in FIG. Work and run in a state of being. In this state, there is little possibility that an excessive force in the twisting direction is applied to the swing position adjusting portion 25 at the support position on the vehicle body side of the first link 21, and the load of the vehicle body 1 is mainly caused by the hydraulic cylinder 26. Can receive. As a result, the hydraulic control can be easily performed, and the posture control of the vehicle body 1 can be performed accurately.

For example, when the work vehicle turns in a relatively narrow work area, when the work vehicle is stored in a storage place, or when the work vehicle is transported by a transport vehicle, the first link 21 is provided as shown in FIG. Switch to the inward swing position. In this state, the external dimensions of the work vehicle in the front-rear direction are reduced to obtain a compact shape.

When the work vehicle travels on a slope or on a flat and leveled road surface at high speed, the first link 21 is switched to the outward swing position as shown in FIG. Work run. In this state, the distance between the front and rear traveling devices 2 becomes wide, and the vehicle can travel stably in a low center of gravity state.

The hydraulic cylinder 26 is located on the outer side in the front-rear direction of the vehicle body with respect to the first link 21, and is provided so as to substantially follow the longitudinal direction of the first link 21. The hydraulic cylinder 26 is interlocked with the base end side arm portion 21b whose base end side (upper side) end portion is integrally formed on the base end side of the first link 21. The swing side (lower side) end of the hydraulic cylinder 26 is interlocked and connected to the arm portion 22A integrally formed at the base end side portion of the second link 22 via the arc-shaped first interlocking member 32. ing. The swing-side end of the hydraulic cylinder 26 is also interlocked and connected to the swing-end side of the first link 21 via another second interlocking member 33. The ends of both sides of the first interlocking member 32 and the second interlocking member 33 are pivotally connected so as to be relatively rotatable.

When the hydraulic cylinder 26 is expanded and contracted, the second link 22 and the traveling device 2 are integrally formed with the first link 21 and the second link 22 while the posture of the first link 21 with respect to the vehicle body 1 is maintained constant. It swings around the horizontal axis X2 of the connection point of.

The auxiliary wheels 3 are supported by the intermediate refraction portions of each of the four refraction link mechanisms 4 so as to be freely rotatable. As shown in FIGS. 1 and 2, the training wheels 3 are composed of wheels having substantially the same outer diameter as the drive wheels 7 of the traveling device 2. As shown in FIG. 3, the connecting support shaft 34 that pivotally connects the first link 21 and the second link 22 is extended so as to project outward in the lateral width direction of the vehicle body from the second link 22. .. The training wheels 3 are rotatably supported at the extension protruding portion of the connecting support shaft 24. That is, the connecting support shaft 24 that pivotally connects the first link 21 and the second link 22 is configured to also serve as the rotating support shaft of the training wheels 3, and the configuration is simplified by also using the members. ing.

As shown in FIGS. 7 and 8, the refraction link mechanism 4, the traveling device 2, the training wheels 3, and the hydraulic cylinder 26 are integrally rotatably outward around the axis Y of the rotation support shaft 19. It is supported by the lateral pivot bracket 17. Then, by expanding and contracting the swivel cylinder 14, they are integrally rotated. The traveling device 2 can be turned by about 45 degrees in each of the left turning direction and the right turning direction from the straight traveling state facing the front-rear direction.

When the bolt connection of the connecting member 16 to the front-rear frame body 15 is released, the swivel mechanism 12, the refraction link mechanism 4, the traveling device 2, the training wheels 3, and the hydraulic cylinder 26 are integrally assembled. Then, it can be removed from the vehicle body 1. Further, by bolting the connecting member 16 to the front-rear frame body 15, the devices can be attached to the vehicle body 1 in a state of being integrally assembled.

The hydraulic oil is supplied and discharged from the hydraulic oil supply device 6 to the hydraulic cylinders 26 of each of the plurality of refraction link mechanisms 4, so that the hydraulic cylinders 26 can be expanded and contracted. By adjusting the flow rate of the hydraulic oil with respect to the hydraulic motor 9, the rotation speed of the hydraulic motor 9, that is, the drive wheels 7 can be changed.

As shown in FIG. 1, this work vehicle is equipped with various sensors. Specifically, the hydraulic cylinder 26 is provided with a first head side pressure sensor S1 and a first cap side (anti-head side) pressure sensor S2. The first head side pressure sensor S1 detects the oil pressure in the head side chamber of the hydraulic cylinder 26. The first cap side pressure sensor S2 detects the oil pressure in the cap side chamber of the hydraulic cylinder 26. Although not shown, each of the hydraulic cylinders 26 and 14 has a stroke sensor capable of detecting the expansion / contraction stroke amount, and is configured to feed back the operating state to the control device 11.

The mounting positions of the pressure sensors S1 and S2 are not limited to the above positions. The pressure sensors S1 and S2 may be provided in the pipe between the valve mechanism and the corresponding cap side chamber or head side chamber as long as the oil pressure of the corresponding cap side chamber or head side chamber can be detected (estimated).

Based on the detection results of these sensors, the force required to support the vehicle body 1 is calculated, and the supply of hydraulic oil to each hydraulic cylinder 26 is controlled based on the result. Specifically, based on the detected value of the first head side pressure sensor S1 and the detected value of the first cap side pressure sensor S2, the cylinder of the hydraulic cylinder 26 is based on the differential pressure between the cap side chamber and the head side chamber of the hydraulic cylinder 26. The thrust is calculated.

The vehicle body 1 is provided with an acceleration sensor S3 including, for example, a three-axis acceleration sensor. Based on the detection result of the acceleration sensor S3, the inclination of the vehicle body 1 in the front-rear and left-right directions is detected, and the posture of the vehicle body 1 is controlled based on the result. That is, the supply of hydraulic oil to each hydraulic cylinder 26 is controlled so that the posture of the vehicle body 1 becomes the target posture.

The traveling device 2 is provided with a rotation sensor S4 that detects the rotation speed of the drive wheels 7. Based on the rotation speed of the drive wheels 7 calculated by the rotation sensor S4, the supply of hydraulic oil to the hydraulic motor 9 is controlled so that the rotation speed of the drive wheels 7 becomes a target value.

As described above, the work vehicle of the present embodiment has a configuration in which the posture of the refractory link mechanism 4 supporting the drive wheels 7 is changed by the hydraulic cylinder 26, and the traveling drive is also performed by the hydraulic motor 9. Therefore, unlike an electric motor or the like, it is not easily affected by moisture or fine dust, and is suitable for agricultural work.

When traveling on a flat ground, it is possible to travel in any of a plurality of different traveling modes. That is, as shown in FIGS. 9 to 11, all four drive wheels 7 and four auxiliary wheels 3 are in contact with the ground, and as shown in FIGS. 12 and 15, all four drive wheels 7 are in contact with the ground. In addition, all four auxiliary wheels 3 are in a four-wheel running state in which they rise from the ground. FIG. 15 shows a state in which the vehicle travels across the ridges. In addition to the above-described traveling mode, as shown in FIG. 13, it is also possible to levitate all four sets of drive wheels 7 and switch to a free moving state for use. In this case, it is not possible to drive the vehicle, but it can be easily pushed and moved manually.

In this work vehicle, in addition to traveling on a flat surface as described above, as shown in FIG. 14, all four sets of first links 21 are switched to outward swing positions, and the drive wheels 7 and training wheels 7 and auxiliary wheels are switched. It is possible to drive while climbing up the slope with all 3 and 3 touching the ground. In this traveling mode, the ground contact width along the front-rear direction of the vehicle body is widened, and even on a slope with a large inclination, the vehicle can travel in a stable state without tipping over.

[Another Embodiment]
(1) In the above embodiment, the articulated link mechanism is configured to include two links 21 and 22, and the drive operating means 5 is configured to include one hydraulic cylinder 26. It may be configured as follows.

The articulated link mechanism is configured to include three or more links that are pivotally connected so as to have three or more joints, and the posture of links other than the first link is changed as a driving operation means. It may be configured to include one or more hydraulic cylinders. Further, as the drive operating means, a hydraulic motor may be provided at the swing fulcrum portion of the refraction link mechanism 4, and the posture of the refraction link mechanism 4 may be changed by the hydraulic motor.

(2) In the above embodiment, the traveling device 2 is driven by the hydraulic motor 9, but instead of this configuration, for example, the power of the engine mounted on the vehicle is a mechanical transmission mechanism such as a chain transmission mechanism. It may be configured to be supplied to the drive wheels 7 via.

(3) In the above embodiment, the traveling device 2 is provided with one drive wheel 7, but instead of this configuration, the traveling device 2 is a crawler traveling device in which a crawler belt is wound around a plurality of wheels. It may be configured to include.

(4) In the above embodiment, the traveling devices 2 are provided in pairs on the front and rear sides of the vehicle body 1, but the traveling devices 2 are provided in three or five or more traveling devices 2. It may be provided.

(5) In the above embodiment, the hydraulic cylinder 14 for turning operation is provided, but the turning operation may be performed by an electric motor or a hydraulic motor, and the structure does not include an actuator for such turning operation. May be good. In that case, the drive speeds of the left and right traveling devices on the leading side in the traveling direction may be different so that the traveling devices may be turned.

(6) In the above embodiment, as a manually operated position fixing means, the locking rod 31 is inserted and inserted through the engaging hole 30 of the regulating member 29 and the insertion hole 28 of the first link 21 to form three positions. Although the configuration that can be switched to is shown, instead of this configuration, the manual handle is rotated by using a configuration in which it is fixed with a locking rod at four or more positions, or a gear-type boosting mechanism or the like. By doing so, the first link 21 may be configured so that the position can be held steplessly at the position where the position changes.

The present invention can be applied to a work vehicle suitable for traveling on an uneven road surface.

1 Vehicle body 2 Traveling device 4 Articulated link mechanism 5 Drive operation means 14 Hydraulic cylinder for turning operation 21 First link 22 Second link 25 Position fixing means 26 Hydraulic cylinder Y axis

Claims (4)

With the vehicle body
A plurality of traveling devices located on the left and right sides of the vehicle body, respectively, and
A plurality of articulated link mechanisms in which a plurality of links are pivotally connected so as to have at least two or more joints, and the traveling device is supported on the vehicle body so as to be able to move up and down separately.
A drive operating means capable of changing the posture of the articulated link mechanism is provided.
The first link, which is located closest to the vehicle body among the plurality of links, is swingably supported around the horizontal axis with the main body side connecting point as a fulcrum.
A manually operated position fixing means capable of selectively fixing the first link at any of a plurality of preset swing switching positions is provided.
The position fixing means includes a vertical position in which the first link is in a substantially vertical posture, an inward swing position in which the first link swings inward in the front-rear direction of the vehicle body with respect to the vertical position, and a vertical direction. It is configured so that the position can be fixed at each of the outward swinging position that swings outward in the front-rear direction of the vehicle body with respect to the position.
The drive operating means is a work vehicle that changes the posture of a link other than the first link among the plurality of links. In the articulated link mechanism, as the other link, one end is swingably supported by the other end of the first link around the horizontal axis, and the other end supports the traveling device. The work vehicle according to claim 1, which comprises a link. The work vehicle according to claim 1 or 2, wherein the drive operating means is a hydraulic cylinder. The articulated link mechanism is supported by the vehicle body so that the orientation can be changed around the vertical axis core.
The work vehicle according to any one of claims 1 to 3, further comprising a hydraulic cylinder for a turning operation for turning and operating the articulated link mechanism.

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