Title:
Operator's seat supporting device for service vehicle
Kind Code:
A1


Abstract:
An operator's seat (6) is mounted via a posture adjusting mechanism (40) on a supporting plate (3) supported by at least two damper cylinders (50, 30) at a place where an operator's seat is installed, and at least one of the damper cylinders (50, 30) is used as a damper cylinder (50) for reducing vibrations by making use of a magnetic rheological fluid.



Inventors:
Tsuji, Hideki (Hiratsuka-shi, JP)
Tamaru, Masatake (Osaka, JP)
Application Number:
10/922268
Publication Date:
04/07/2005
Filing Date:
08/19/2004
Assignee:
KOMATSU LTD. (Tokyo, JP)
Primary Class:
International Classes:
B60N2/54; (IPC1-7): A47C3/025
View Patent Images:
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Primary Examiner:
GARRETT, ERIKA P
Attorney, Agent or Firm:
HOLTZ, HOLTZ & VOLEK PC (NEW YORK, NY, US)
Claims:
1. An operator's seat supporting device for a service vehicle, wherein at least biaxially supported by damper cylinders each are arranged along an axial line parallel to a vertical line passing through a shoulder of an operator sitting on a seat, and the operator's seat supporting device includes a posture adjusting mechanism provided by the sections supported by the damper cylinders and the seat.

2. An operator's seat supporting device for a service vehicle, wherein an operator's seat is mounted via a posture adjusting mechanism on a supporting plate supported by at least two damper cylinders at a place where an operator's seat is installed, and at least one of the damper cylinders reduces vibrations by making use of a magnetic rheological fluid.

3. The operator's seat supporting device for a service vehicle according to claim 2, wherein, in the damper cylinder for reducing vibrations by making use of the magnetic rheological fluid, a buffering cylinder and a control cylinder for controlling vibrations with the magnetic rheological fluid are monolithically formed.

4. The operator's seat supporting device for a service vehicle according to claim 2, wherein the damper cylinder has a biaxial slide supporting structure, and a coil spring is provided in the inner side or in the outer side from a shaft body having dual-shafts.

5. The operator's seat supporting device for a service vehicle according to claim 3, wherein the damper cylinder has a biaxial slide supporting structure, and a coil spring is provided in the inner side or in the outer side from a shaft body having dual-shafts.

6. The operator's seat supporting device for a service vehicle according to claim 2, wherein an operator's seat rotating mechanism is provided on the supporting plate supported by the damper cylinders.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an operator's seat supporting device for a service vehicle having a variable damping mechanism provided mainly in an operator's cabin of a construction machinery and capable of improving the availability.

2. Description of Related Art

The conventional type of supporting device for an operator's seat provided in an operator's cabin of a construction machine such as a hydraulic shovel or a bulldozer receives a larger shock delivered to the seat on which the operator sits as compared to that delivered to an operator's seat in a general industrial vehicle, and there have been proposed various measures for a suspension structure for reducing the shock.

As a suspension structure for an operator's seat in this type of service vehicle, there has been known one, for instance, as shown in FIG. 9A and FIG. 9B. In this suspension structure, an X-shaped link 102 with the link members crossing each other in the longitudinal direction and linked to each other with a pin 103 at a crossing point on a base member 101 are provided with a prespecified space in both right and left sides thereof, and a link 110 with the height adjustable is provided between the right and left X-shaped links 102, 102.

In the X-shaped link 102, a base edge of one link member 102a is pivotably connected to the base member 101 with the other edge connected to a seat mounting base frame 104 with a pin 105, and a lower edge of another link member 102b can move on the base member 101 with the upper edge connected to the seat mounting base frame 104 with a pin 106, and the cushioning capability is provided by a suspension cylinder 107.

The height-adjustable link 110 is rolled in the state in which a roller 111 provided at a lower edge thereof is engaged with a guide rail 108 provided on the base member 101 with an upper edge thereof linked to an edge of a coil spring 112 on the seat mounting base frame 104 so that the tension is energized in the erecting direction, and further an adjustment knob 113 capable of adjusting the weight and height by displacing the link 110 in the vertical direction by means of adjusting tension of the spring 112 is provided therein. In the figures, the reference numeral 115 indicates a seat, and the reference numeral 116 indicates a suspension cover.

Reference 1 (Japanese Patent Laid-Open Publication No. HEI 9-209406) discloses a suspension structure in which a forward section thereof is supported with a rubber spring system which elastically deforms little in the vertical direction, and a rear section thereof is supported by a coil damper unit system which elastically deforms largely in the vertical direction. In addition, a suspension mechanism for an operating seat using the X-shaped link is disclosed, for instance, in Reference 2 (Japanese Patent Laid-Open Publication No. HEI 11-280117).

However, with the supporting means for an operator's seat employing the X-shaped link 102 as used in the conventional technology, the link 102 occupies a space under the seat 115, which narrows a space under the operator's feet.

Further there is another disadvantage that a damper is provided externally, which disables effective utilization of the space.

In addition, the X-shaped link is generally made from flat steel bars, so that the rigidity in the lateral direction is disadvantageously low, and as the joint section includes a pin, and therefore there is another disadvantage that it is difficult to insure strength against load.

As the mechanism for adjusting a body weight is integrated with that for adjusting the height, it is difficult to achieve the complete balance between an operator's body type and the operator's body weight.

Namely, when an operator is a person not having the standard body type such as a relatively heavy person having the low seating height or a person having the relatively high seating height against the body weight, if a seat height is adjusted to the operator's posture, the buffering function is disadvantageously lost, which is another problem.

In the suspension seat structure as disclosed in the cited reference 1, as dampers having different structures respectively are provided in the front of and at the back of the seat, and the dampers are required to be adjusted discretely, and in addition the damper provided at the back of the seat is attached to an outer side of a backrest of the seat, so that, when an inclination of the backrest is changed, the buffering effect also varies, which is disadvantageous from a view point of structure and not preferable because of its complicated structure.

The suspension device in the operator's seat device disclosed in the cited reference 2 also has the problems as described above.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an operator's seat supporting device for a service vehicle with a compact suspension mechanism with improved functions and capable of ensuring operator's comfortable posture during the operation.

In an operator's seat supporting device for a service vehicle according to an aspect of the present invention, at least biaxially supported by damper cylinders each are arranged along an axial line parallel to a vertical line passing through a shoulder of an operator sitting on a seat, and the operator's seat supporting device includes a posture adjusting mechanism provided by the sections supported by the damper cylinders and the seat.

In an operator's seat supporting device for a service vehicle according to another aspect of the present invention, an operator's seat is mounted via a posture adjusting mechanism on a supporting plate supported by at least two damper cylinders at a place where an operator's seat is installed, and at least one of the damper cylinders reduces vibrations by making use of a magnetic rheological fluid.

Preferably, with the above operator's seat supporting device for a service vehicle, in the damper cylinder for reducing vibrations by making use of the magnetic rheological fluid, a buffering cylinder and a control cylinder for controlling vibrations with the magnetic rheological fluid may be monolithically formed.

Preferably, with the operator's seat supporting device for a service vehicle, the damper cylinder may have a biaxial slide supporting structure, and a coil spring may be provided in the inner side or in the outer side from a shaft body having dual-shafts.

Preferably, with the operator's seat supporting device for a service vehicle, an operator's seat rotating mechanism may be provided on the supporting plate supported by the damper cylinders.

With the configuration as described above, an area occupied by a seat supporting section on a floor surface can be reduced, whereby a wide space can be provided under an operator's feet to secure that the operator can take a comfortable posture during the operation.

Further there is also provided the advantage that a floor surface of the operator's cabin can easily be cleaned.

With the configuration as described above, in addition to the advantages described above, there is provided the advantage that the height adjustment of the seat can be carried out independently from adjustment of a body weight of an operator sitting thereon with the optimal height provided to secure that the operator can take a more comfortable posture during the operation. Further by making use of a magnetic rheological fluid, a vibration damping force can variably be set according to change of the magnetic field, and a damping force can previously be set according to an operator's body weight, which advantageously improves the buffering effect against a shock by an external force.

When the configuration as described above is employed, the structure is compact, so that a space required for installation thereof can be reduced, so that the occupied space under operator's feet can be minimized to secure that the operator can take a comfortable posture during the operation.

With the configuration described above, a damper cylinder functioning as a supporting body has a biaxial slide structure, so that only a further small space is required, and a load is shared by a plurality of damper cylinders, so that the stable supporting force can be obtained without causing any saccadic movement.

Further with the configuration described above, a rotating mechanism is provided on a supporting plate supported by the damper cylinder, so that a rotating movement can be carried out without spoiling the buffering function of the seat.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view showing a first embodiment of an operator's seat supporting device for a service vehicle according to the present invention;

FIG. 2 is a side elevational view of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view showing a damping function control mount;

FIG. 4 is a cross-sectional view showing the primary portion of the damping function control mount cylinder;

FIG. 5 is a longitudinal cross-sectional view showing a supporting damper;

FIG. 6 is a cross-sectional view showing a second embodiment of a damping function control mount cylinder;

FIG. 7 is a cross-sectional view showing the primary portion of the damping function control mount cylinder according to the second embodiment;

FIG. 8 is a cross-sectional view showing a third embodiment of a damping function control mount cylinder;

FIG. 9A is a side elevational view showing an embodiment of a supporting structure for an operator's seat based on the conventional technology; and

FIG. 9B is a view showing the operator's seat based on the conventional technology viewed from the front side.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

Embodiments of an operator's seat supporting device for a service vehicle according to the present invention is described below with reference to the related drawings.

First Embodiment

FIG. 1 is a front elevational view showing a first embodiment of the operator's seat supporting device for a service vehicle according to the present invention; FIG. 2 is a side elevational view of FIG. 1; FIG. 3 is a longitudinal cross-sectional view showing a damping function control mount; FIG. 4 is a cross-sectional view showing the primary portion of the damping function control mount cylinder; and FIG. 5 is a longitudinal cross-sectional view showing a supporting damper.

An operator's seat supporting device 1 according to this embodiment includes two damper cylinders 50, 30 erecting from and provided on a floor surface 2 of an operator's cabin with a prespecified space; a posture adjusting section 40 provided on a movable supporting plate 5 disposed via a rotating mechanism 4 on a supporting plate 3 supported by these damper cylinders 50, 30; and an operator's seat 6 mounted via this posture adjusting section 40.

Of the damper cylinders 50, 30, one is a damping function control mount 50 (described simply as a damper cylinder 50 hereinafter) having a magnetic rheological fluid control function, and the other is a damper cylinder 30 for supporting (supporting damper).

The damper cylinder 50 having a magnetic rheological fluid control function includes, as shown in the cross-sectional view in FIG. 3, a buffering cylinder 53 externally and coaxially engaging a fixed member 51 having a mounting base 52 against the floor surface 2 (corresponding to the biaxial slide support structure according to the present invention), a coil spring 59 for restoring a damper provided inside the fixed member 51, and a control cylinder 60 for a magnetic Theological fluid associated with the buffering cylinder 53 and capable of controlling operations of the buffering cylinder 53, and a mounting base plate 58′ for mounting the supporting plate 3 thereon is provided on a top of the buffering cylinder 53.

The buffering cylinder 53 is a tubular cylinder including a movable member 54 provided outside and the fixed member 51 provided inside and coaxially engaged therewith.

The movable member 54 is so connected that a male screw 54b formed on an external peripheral surface of an upper end of the cylinder member 54a is screwed to a female screw 54d formed on an internal peripheral surface of a drooping spherical base section 54c. Further, a female screw 54e is formed on an inner peripheral surface of a lower end of the cylinder member 54a, to which a cover member 54f with a male screw formed is screwed.

An internal capacity of the cylinder is controlled to a prespecified value by the cylinder member 54a, the base section 54c and the cover member 54f.

The buffering cylinder 53 is slidably assembled with the fixed member 51 with a circular projection 55 functioning as a piston integrally provided at an intermediate section of the fixed member 51, and a seal ring 55b is engaged in a groove section 55a formed on an outer peripheral surface of the circular projection 55 and contacts an internal surface of the movable member 54 (cylinder member 54a) with a first chamber 56a and a second chamber 56b defined vertically.

Incidentally, the internal peripheral surface of the cylinder member 54a located at an upper edge section of the first chamber 56a is projected in a ring-shaped manner, and a seal ring 56c is fitted to a groove formed at the tip end thereof. Further, the screwing portion of the cover member 54f located at a lower edge section of the second chamber 56b is formed cylindrical, and seal rings 56d and 56e are fitted to grooves formed on upper and lower sides of the internal peripheral surface thereof. With the use of the seal rings 56c, 56d and 55b, the sealability of the first chamber 56a and the second chamber 56b is secured. Additionally, the seal ring 56e inhibits the dust entering from the outside.

The control cylinder 60 includes a cylindrical main body 61, an upper cover member 63 and a lower cover member 63′ that cover holes 62 opening at the upper and lower part of the cylindrical main body 61.

An insert body 64 is provided inside the cylindrical main body 61 on the center line of the cylindrical main body 61, the upper and lower edges of the insert body 64 is joined and fixed to the cylindrical main body 61 as well as to the lower cover member 63′.

The insert body 64 includes a clearance forming section 64a made of a magnetic material such as electromagnetic soft iron, and a shaft 64b made of a non-magnetic material such as stainless, the shaft 64b press-fitted to the upper and lower edges of the clearance forming section 64a.

On the other hand, as shown in FIG. 4, a bobbin 61a made of a non-magnetic material is embedded on an inner peripheral surface of the cylindrical main body 61 corresponding to the position of the clearance forming section 64a. A coil 61b with a lead wire being winded is provided around the bobbin 61a, the end of the lead wire being connected to a controller provided at the outside of the damper cylinder 50. The bobbin 61a and the coil 61b function as an electromagnetic control section that controls the viscosity of the magnetic rheological fluid flowing through the cylinder.

Two connecting holes 65 are formed at the upper and lower parts of a lateral surface of the cylindrical main body 61 to communicate the inside and the outside thereof, and the connecting holes 65 are respectively connected to two connecting holes 54g penetrating the inside and the outside of the cylinder member 54a via a cylindrical connecting member 66. It is to be noted that the one of connecting holes 54g is connected to the first chamber 56a while the other one is connected to the second chamber 56b.

Further a buffering chamber 67 is provided below the upper cover member 63, so that expansion of the magnetic rheological fluid to be sealed therein due to temperature change can be accommodated.

When the insert body 64 is installed in the cylindrical main body 61, as shown in FIG. 4, the interior of the cylindrical main body 61 is divided into the upper side chamber 62a and the lower side chamber 62b by interposing the clearance forming section 64a, thereby forming a space S between the inner surface of the cylindrical main body 61 and the outer surface of the clearance forming section 64a. The space S functions as a restrictor for adjusting the fluid flow rate flowing between the upper side chamber 62a and the lower side chamber 62b.

A magnetic rheological fluid (such as, for instance, iron carbonyl particles suspended in mineral oil as a carrier) is filled in each of the control cylinder 60 and the buffering cylinder 53 each having the configuration as described above.

In contrast to the damper cylinder 50 as described above, the damper cylinder 30 for supporting includes, as shown in FIG. 5, a fixed member 31 having a column-like form with a mounting base 32 attached at a lower edge thereof, a tubular movable member 34 engaged with this fixed member 31 and having a base plate for mounting the supporting plate 3 thereon; and a coil spring 37 provided concentrically with the lower edge supported by a top surface of a bottom edge member 31a of the fixed member 31 and also the upper edge thereof contacting an internal bottom surface of a mounting cap member 35 of the movable member 34.

The fixed member 31 has the structure in which the bottom edge member 31a which is a tubular body having prespecified dimension and closes the lower edge section of the fixed member 31 is attached, and the mounting base 32 is monolithically attached to this bottom edge member 31a with the upper edge section opened.

A circular member 34a is monolithically attached to an upper edge section of the movable member 34, and the cap member 35 is screwed into an upper edge section of this circular member 34a to close the upper section. Monolithically attached to a top surface of this cap member 35 is a mounting base plate 38 for supporting the supporting plate 3.

Bearings 36, 36′ are monolithically attached to an internal peripheral surface of the circular member 34a of the movable member 34 and a portion 34b thereof with the internal peripheral section of the lower edge section having a smaller diameter respectively so that the fixed member 31 can be slid in the vertical direction without losing the concentric positional relation thereto.

As shown in FIGS. 1 and 2, the damper cylinders 50, 30 having the configuration as described above respectively are provided in the erecting state on a floor surface of the operator's cabin so that the center line is substantially aligned to a vertical plane (vertical line C) passing through a shoulder Q′ of an operator Q when the operator Q sits on the seat 6 with the normal posture with the mounting bases 52, 32 attached to the damper cylinders 50, 30 respectively. These two damper cylinders 50, 30 support the supporting plate 3 having a dimension slightly larger than the width of a seat plate section 6a of the seat 6.

With the configuration as described above, the operator Q sitting on the seat 6 is supported by the damper cylinders 50, 30 at a position on a line passing through a gravity center or a position close to the gravity center of the operator Q, so that, although the operator Q is supported by two damper cylinders, vibrations in the longitudinal direction and those in the lateral direction do not occur, and the seat 6 is securely supported with the simple supporting structure.

A swivel ring (rotating mechanism 4) is provided with the shaft center positioned at a central position of a line connecting centers supported by the damper cylinders 50, 30 on the supporting plate 3, and the movable supporting plate 5 is attached thereto with a supporting member 4b attached to the swivel ring so that the swivel ring can freely swivel.

Slide mechanisms 41 each for adjusting an operator's position in the longitudinal direction as a posture adjusting section 40 and a height adjusting mechanism 42 are provided on the movable supporting plate 5, and the seat 6 is attached thereto via the height adjusting mechanism 42.

The slide mechanisms 41 each extending in the longitudinal direction are arranged with a prespecified space in the lateral direction, and a mounting base member 7 of the seat 6 is supported by the movable member. The slide mechanism 41 has a known structure, and a movable member can intermittently move in the longitudinal direction thereon along a rail so that a position of the operator Q in the longitudinal direction can be adjusted.

The height adjusting mechanism 42 having a known structure is provided on the mounting base member 7, and a seat plate section 6a of the seat 6 is attached with a known means to a seat mounting frame body above this height adjusting mechanism 42. The height adjusting mechanism 42 employed in the present invention can adjust a position in the vertical direction with cross links. It is to be noted that also the height adjusting mechanism 42 not employing the cross links may be used in the present invention.

The reference numerals 8 and 8′ each indicate a console in which an operating lever or other operating sections of machines and equipments are accommodated, and this console 8 is monolithically attached with a bracket to the mounting base member 7, and can move in the vertical direction and swivel together with the operator's seat 6 to allow for operations without requiring an operator to change the positional relation therewith. The reference numeral 6b in the figure indicates a backrest.

The operator's seat supporting device 1 according to this embodiment is installed in an operator's cabin (not shown) of a service vehicle, and supports the operator's seat 6 as described above.

The operator's seat supporting device 1 having the configuration as described above according to this embodiment can set an operator's position in the longitudinal direction with the slide mechanisms 41 and the operator's height with the height adjusting mechanism 42 respectively, when the operator adjusts the operating posture.

The two damper cylinders 50, 30 are balanced with the energizing forces of the coil springs 59, 37 respectively in the normal state to support the operator's seat 6.

Vibrations due to a shock or any other load from the outside during the operation are damped by the two damper cylinders 50, 30 supporting the seat 6, and one damper cylinder 50 has a function for controlling attenuation with an electromagnetic control section with a magnetic rheological fluid included therein, and with the configuration as described above, a signal from a sensor for detecting vibrations previously installed in an operator's cabin or on a machine frame is received by the controller, and a current is flown at a required rate to the coil 61b of the control cylinder 60 according to an output signal generated by comparing the received signal to preset data, so that the vibrations are quickly damped by controlling the pressure difference generated between the first chamber 56a and the second chamber 56b in the buffering cylinder 53 from the control cylinder 60, thus the vibration-controlling function being provided.

The other damper cylinder 30 has the function for dampening a shock by following the vibration controlling and buffering function of the damper cylinder 50 with a cushioning function with the coil spring 37 with the movable member 34 against the fixed member 31 provided therein. Therefore, even when a large shock is applied thereto, vibrations can quickly be absorbed and dampened.

As for the vibration controlling action by the damper cylinder 50, when vibrations are delivered from a vehicle's body, the movable member 54 displaces against the fixed member 51 in the axis line direction. When the movable member 54, for example, moves in the downward direction of the vertical direction against the energizing force by the coil spring 59,the cylinder member 54a of the movable member 54 acts to push down the magnetic Theological fluid in the first chamber 56a.

As shown in FIG. 4, the magnetic Theological fluid in the first chamber 56a is pushed out into an upper side chamber 62a of the control cylinder 60 through the connecting hole 54g, the connecting member 66 and the connecting hole 65 by pushing down action of the magnetic rheological fluid. In this step, a reduced pressure state is generated in the second chamber 56b of the buffering cylinder 53, so that the magnetic Theological fluid is fed from a lower side chamber 62b of the control cylinder 60 through the connecting hole 65, the connecting member 66 and the connecting hole 54g into the second chamber 56b.

When the magnetic Theological fluid in the first chamber 56a is moved into the upper side chamber 62a of the control cylinder 60 in association with the downward movement of the movable member 54 in the buffering cylinder 53, the pressure of the second chamber 56b is reduced, so that the pressure of the lower side chamber 62b of the control cylinder 60 communicating the second chamber 56b through the connecting hole 65, the connecting member 66 and the though hole 54g is also reduced.

Therefore, the upper side chamber 62a of the control cylinder 60 enters the pressurized state, while the lower side chamber 62b enters the reduced pressure state, so that the magnetic rheological fluid filled in the upper side chamber 62a flows toward the lower side chamber 62b due to the pressure difference.

In this step, a flow rate of the magnetic rheological fluid is restricted at the space S between the outer surface of the clearance forming section 64a and the inner surface of the cylindrical main body 61, the space S separating the upper side chamber 62a from the lower side chamber 62b.

A vibration signal indicating vibrations of the fluid passing through the space S is sent from the sensor (not shown) to the controller, and the coil 61b is energized at a prespecified current rate based on preset data so that the magnetic field corresponding to the current is generated between the clearance forming section 64a made of a magnetic material and the cylindrical main body 61 with the flowing magnetic Theological fluid magnetized, thereby the magnetic rheological fluid being magnetized to change the viscosity. In other words, fluidity of the magnetic Theological fluid changes in proportion to intensity of the magnetic field.

When the movable member 54 moves in the upward direction, the magnetic Theological fluid flows between the control cylinder 60 and the buffering cylinder 53 in the direction reverse to that in the operating sequence described above with the flow state controlled.

By changing the flow state of the magnetic rheological fluid as described above to change the flow resistance of the magnetic rheological fluid in flowing, the movement speed in the vertical direction of the buffering cylinder 53 is controlled to dampen a shock loaded thereto.

In a case of an operator's seat in an operator's cabin provided in a bulldozer, when a large shock such as that experienced in running over a large rock or a projection, for instance, when a vehicle moves backward is loaded thereto, for dampening the vibrations caused by the shock, with the use of the above-described electromagnetic control section in the control cylinder 60, by raising a rate of a current loaded from the controller to a level higher than that in the normal state to raise the intensity of a magnetic field generated between the cylindrical main body 61 and the clearance forming section 64a proportionately, the apparent viscosity of the magnetic rheological fluid flowing through the space S is made larger with the flow resistance at space S raised, so that the flow velocity of the movable member 54 is reduced.

In other words, the cushioning function of buffering a sudden and heavy shock with a soft buffering action provided by a soft spring action and also suppressing vibrations occurring after the shock is loaded by giving a damping force with the control cylinder 60 is achieved in the present invention as described above.

Against the small and successive shocks experienced when driving on an irregular ground surface, by sending a control signal in the direction for lowering the intensity of a magnetic field from the controller to the coil 61b in response to a detection signal from the sensor to lower the magnetic flux density to the magnetic rheological fluid in the control cylinder 60 with the electromagnetic control section, the flow resistance is reduced with the fluidity of the magnetic rheological fluid raised contrary to the case described above, so that a movement rate of the movable member 54 in the axial direction in the buffering cylinder 53 is reduced, and therefore soft and smooth action for dampening vibrations is provided.

In contrast to the damper cylinder 50 having the functions as described above, the other damper cylinder 30 has a supporting function with a simple structure including the coil spring 37 for buffering therein, and performs the supporting function in association with actions of the damper cylinder 50 as a damper cylinder supporting the whole seat 6 leaving a main portion of the vibration-controlling function for dampening vibration to the damper cylinder 50.

With the configuration, the seat 6 is smoothly buffered against vibrations with the two damper cylinders 50, 30, thus comfortable and smooth operations being insured to an operator.

As described above, the operator's seat supporting device 1 according to this embodiment has the configuration in which vibrations are dampened with a vibration buffering device completely different and independent from the seat height adjusting mechanism 42, so that adjustment in response to an operator's body weight is not required, and the efficient buffering function can be provided in the optimal state only by carrying out positional adjustment according to the operator's body type, thereby the operator performing required operations in the comfortable state. Further a wide space can be secured under an operator's feet, so that the problem of narrow space under the operator's feet as experienced in the supporting device based on the conventional technology can be eliminated, whereby there is provided the advantage that an operator can perform various operations in a relaxed and comfortable posture.

Second Embodiment

Next, referring to FIG. 6, a second embodiment of the present invention is described below.

In the present embodiment, it is only different from the operator's seat supporting device I according to the first embodiment that the structure of the damper cylinder 50 (damping function control mount cylinder) is modified. In the following, the description of the components have been described already or that of the same components as the above-described components will be omitted or simplified.

The damper cylinder 10 according to the second embodiment having a magnetic Theological fluid control function includes, as shown in the cross-sectional view in FIG. 6, a buffering cylinder 13 externally and coaxially engaging a fixed member 11 having a mounting base 12 against the floor surface 2 (corresponding to the biaxial slide support structure according to the present invention), a coil spring 19 for restoring a damper provided inside the fixed member 11, and a control cylinder 20 for a magnetic rheological fluid associated with the buffering cylinder 13 and capable of controlling operations of the buffering cylinder 13, and a mounting base plate 18′ for mounting the supporting plate 3 thereon is provided on a top of the buffering cylinder 13.

The buffering cylinder 13 is a tubular cylinder including a movable member 14 provided outside and the fixed member 11 provided inside and coaxially engaged therewith. The movable member 14 has a thick circular member 14b connected to and integrated with an upper edge section of the cylinder member 14a and also has a circular head member 14c screwed into a lower edge section thereof, and controls an internal capacity of the cylinder to a prespecified value with an internal lower edge of the circular member 14b fixed to an upper edge section of the cylinder member 14a and an internal upper edge of the head member 14c.

The buffering cylinder 13 is slidably assembled with the fixed member 11 with a circular projection 15 functioning as a piston integrally provided at an intermediate section of the fixed member 11, and a seal ring 15b is engaged in a groove section 15a formed on an outer peripheral surface of the circular projection 15 and contacts an internal surface of the movable member 14 (cylinder member 14a) with a first chamber 16a and a second chamber 16b defined in front and at the back thereof. A seal ring 16d is engaged in each of the first chamber 16a and the second chamber 16b to restrict the fluid from leaking from the inside of the cylinder.

Bearing bushes 17 guided by the fixed member 11 are provided in the circular member 14b and the head member 14c each connected to the movable member 14 respectively, and with the bearing bushes 17 the movable member 14 can slide up and down being aligned with the center line and also accommodate a load applied to the supporting plate 3 in the stable state. Therefore the two bearing bushes 17, 17 should preferably be arranged with a space between the two within a reasonable range. A seal member 17′ is provided in the engaging state at an outer side from the engaging position of the bearing bush 17 so that the chambers 16a and 16b are water-tight against the outside. A cap member 18 is screwed into the circular member 14b at a top section of the buffering cylinder 13 having the configuration as described above, and a mounting base plate 18′ for mounting the supporting plate 3 thereon is attached to this cap member 18.

The control cylinder 20 has a hole 22 with a prespecified internal diameter penetrating through a main body 21 with prespecified dimensions in the vertical direction and also has an upper cover member 23 and a bottom cover member 23′ provided to close two edge sections of this penetrating hole 22. A supporting member consisting of a coil section 25 and a sleeve 24a is provided between the upper cover member 23 and the bottom cover member 23′, and the supporting member is so arranged that the coil section 25 is located at an intermediate position of the supporting member supported by the sleeve 24a made from a non-magnetic material with the upper and bottom sections engaged with the supporting member.

A slight clearance “a” is formed between an internal peripheral surface of the main body 21 and an external peripheral surface of a bobbin 25a of the coil section 25. A lead wire 27 extending over a controller not shown enabling electric control is connected to a coil 25b of the coil section 25, and the coil 25b is attached to the bobbin 25a made of magnetic material as the core of a wire-wound section of the coil section 25 with the small clearance “a” defined and maintained between the bobbins 25a and an internal peripheral surface of the cylinder member 26 to form an electromagnetic control section causing a flow resistance of the magnetic Theological fluid. The main body 21 is made from an electromagnetic soft iron for example so that a magnetic field is strongly formed only in the range of the bobbin 25a.

In the main body 21, connecting holes 28a and 28b communicating to the first chamber 16a and the second chamber 16b inside the cylinder member 14a of the buffering cylinder 13 are provided with appropriate spaces from the cylinder member 26 respectively so that the magnetic rheological fluid can flow from the control cylinder 20 to the buffering cylinder 13. Further a buffering chamber 29 with gas such as the air included therein is provided at the top of the control cylinder 20 so that expansion of the magnetic rheological fluid due to temperature change can be accommodated. A magnetic rheological fluid (such as, for instance, iron carbonyl particles suspended in mineral oil as a carrier) is filled in each of the control cylinder 20 and the buffering cylinder 13 each having the configuration as described above.

As shown in FIG. 7, the electromagnetic control section causing a flow resistance in the magnetic rheological fluid in the control cylinder 20 includes a cylinder member of the control cylinder 20 and the coil section 25 provided therein, and also includes a known controller not shown and connected with the lead wire 27 to the coil section 25. The coil section 25 is energized via the controller through the lead wire 27.

The electromagnetic control section controls a signal from a sensor for detecting vibration provided, for instance, in an operator's cabin not shown, and changes intensity of a magnetic flux generated between the bobbin 25a and the main body 21 by flowing a prespecified rate of electric current to the coil section 25 according to an output signal therefrom, so that the electromagnetic control section can increase or reduce the flow resistance by changing the apparent viscosity (fluidity) of the magnetic rheological fluid within the magnetic field when the magnetic Theological fluid flows through the narrow clearance “a” formed between the bobbin 25a and an internal wall of the main body 21 to control the vibration-controlling function.

Even when such damper cylinder 10 according to the second embodiment is applied to the operator's seat supporting device 1, the same advantages as that of the first embodiment can be obtained.

Third Embodiment

Next, FIG. 8 is a cross-sectional view showing a third embodiment of a damping function control mount cylinder.

Basic configuration of the damping function control mount cylinder (described simply as a damper cylinder 10A hereinafter) is the same as that in the embodiment described above, but the combinatorial structure is different from that in the embodiment described above. Therefore the basic actions and effects are the same as those described in the respective embodiments described above. It is to be noted that the same reference numerals are assigned to the same components as those in the embodiment described above and detailed description is omitted herefrom. Therefore description is made only to components having different functions respectively.

The damper cylinder 10A according to this embodiment has a control cylinder 20A incorporated in and at a central position of the buffering cylinder 13A.

Further a coil spring 19A for restoration is provided between a mounting base 12A provided outside the buffering cylinder 13A and attached to a lower edge of the fixed member 11A and a mounting base plate 18a provided at an upper edge of the movable member 14A.

The buffering cylinder 13A includes the fixed member 11A having the mounting base 12A and the movable member 14A sliding in the axis line direction in the inner side therefrom, which are combined with each other.

The fixed member 11A constituting the buffering cylinder 13A has the mounting base 12A in the lower section, and in the upper section, a head member 11b is screwed into and fixed to an upper edge section of the cylinder member 11a which is a main body of the fixed member 11A.

Further a lower section member 11c is fixed to a lower edge section of the cylinder member 11a, and a circular projection 15A of the movable member 14A is slidably provided between an upper edge of the lower section member 11c and a lower edge of the head member 11b, so that the first chamber 16a is separated from the second chamber 16b by the circular projection 15A.

The movable member 14A is a tubular body slidably and coaxially engaged in the fixed member 11A, in which an upper edge section thereof protrudes by an appropriate length from an upper edge of the fixed member 11A, and at the top, the mounting base plate 18a monolithically formed with a screwed cap 18A for supporting the supporting plate 3 is attached thereto, while a screw mounted cover 14e is provided at the lower edge section to function as a piston and a rod.

The circular projection 15A is provided on an external peripheral surface of the intermediate section of this movable member 14A, and a seal ring 15b is engaged in a groove section 15a formed on the external peripheral surface and contacts an internal peripheral surface of the cylinder member 11a of the fixed member 11A to define a third chamber 16f and a fourth chamber 16g in the cylinder.

The control cylinder 20A is coaxially provided and engaged in the movable member 14A.

At a center of this control cylinder 20A, a supporting member consisting of a coil section 25 and the sleeve 24a is provided with a lower edge thereof engaged in and supported by a shaft supporting hole 14f provided on a top surface of the screw mounted cover 14e and also with an upper edge thereof engaged in a shaft hole 14f′ provided at a center of a bottom surface of a supporting piece 14h engaged in the movable member 14A, and further a cylinder member 26A made from electromagnetic soft iron is concentrically provided outside the supporting member with both edges thereof held by the screw mounted cover 14e and the supporting piece 14h. The coil section 25 is provided at the intermediate position with the upper and lower sections thereof supported by a non-magnetic sleeve 24a with a slight clearance left with an internal peripheral surface of the cylinder member 26A made from electromagnetic soft iron.

A bobbin 25a made of a magnetic material are provided at the wire-winded section of the coil section 25 so as to be the core of the wire-winded section, and a narrow clearance “a” is formed between the bobbin 25a and an internal peripheral surface of the cylinder member 26A. The lead wire 27 leading to a controller (not shown) through inside of the supporting member is connected to the coil 25b of the coil section 25, and a required current is fed through the lead wire 27 under control by the controller.

An internal peripheral surface of the circular projection 15B protruding inward from an internal peripheral section of the movable member 14A slidably contacts an external peripheral surface of the cylinder member 26A of the control cylinder 20A via a seal ring 15d engaged in a groove section 15c provided on the peripheral surface so as to be slidable, and the third chamber 16f and the fourth chamber 16g partitioned in the vertical direction by the circular projection 15B is formed between the cylinder member 26A and an internal peripheral surface of the movable member 14A.

A connecting hole 14j communicating to the first chamber 16a and the third chamber 16f and a connecting hole 14k communicating to the second chamber 16b and the fourth chamber 14g are provided above and under internal and external circular projections 15A, 15B of the movable member 14A, and further a connecting hole 26a communicating to the third chamber 16f and the upper side chamber 22a inside the control cylinder 20A and a connecting hole 26b communicating to the fourth chamber 16g and the lower side chamber 22b of the control cylinder 20A are provided in the cylinder member 26A respectively.

The chambers described above are filled with a magnetic rheological fluid. Further seal rings are provided at an upper edge section of an internal peripheral surface of the head member 11b positioned on the fixed member 11A and at a lower edge section of an internal peripheral surface of the lower section member 11c respectively to keep inside of the cylinder water-tight.

The damper cylinder 10A having the configuration as described above is arranged like in the embodiment described above and is used to excite the coil section 25 of the control cylinder 20A under control by the controller, and the functions are the same as those described in the embodiment above.

As for the flowing state of the magnetic rheological fluid, when the movable member 14A is pushed down, the circular projections 15A, 15B move downward, so that, in the buffering cylinder 13A, the fluid in the second chamber 16b is pressurized and flows through the connecting hole 14k into the fourth chamber 16g, and is further fed from this fourth chamber 16g through the connecting hole 26b into the lower side chamber 22b of the control cylinder 20A. In contrast, the first chamber 16a and the third chamber 16f in the buffering cylinder 13A enter the reduced pressure state, so that the fluid in the upper side chamber 22a of the control cylinder 20A passing through the connecting hole 14j flows from the third chamber 16f into the first chamber 16a due to a pressure difference.

In the control cylinder 20A, the magnetic rheological fluid flows from the lower side chamber 22b through the clearance “a” into the upper side chamber 22a due to a pressure difference between the lower side chamber 22b and the upper side chamber 22a.

With the configuration, movement velocity of the buffering cylinder 13A is controlled by controlling a signal from a detection sensor (not shown), which is provided in the machine side against the magnetic rheological fluid and detects vibrations of the magnetic rheological fluid passing through the clearance “a”, with the controller based on data to feed a current at a required rate through the lead wire 27 to the coil section 25 and generate a magnetic field corresponding to the current value around the bobbin 25a for the purpose to change fluidity of the magnetic Theological fluid to control the flow resistance.

The descriptions above assume the configuration in which two units of damper cylinders are employed to support an operator's seat, but the present invention is not limited to this configuration, and for instance, another additional damper cylinder for supporting may be provided in the front side or in the rear side, if necessary. With the configuration, even when a large load is applied to the front side or the rear side of the operator's seat, the load can be accommodated and dampened.