Abstract:
The present invention addresses the problem of providing an industrial vehicle in which an industrial device can be reliably prevented from turning in a near direction beyond a restricted position. The solution is an industrial vehicle provided with an industrial device configured so as to be capable of turning about a joint in a near direction or an away direction, and a control device for restricting the turning of the industrial device so that the industrial device does not turn in the near direction beyond a restricted position, wherein the control device is configured such that an offset position is set in the away direction beyond the restricted position, and the control device initiates an action that stops the industrial device from turning in the near direction when the industrial device, which is turning in the near direction, has turned to the offset position.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an art of an industrial vehicle. 
       BACKGROUND ART 
       [0002]    Conventionally, various arts concerning an industrial vehicle such as an agricultural vehicle, a construction vehicle, an industrial vehicle or the like are known. 
         [0003]    There is the industrial vehicle having a working device and a control device such as a backhoe. 
         [0004]    The working device of the industrial vehicle is equipped with an attachment such as a bucket, an oil pressure breaker, a fork or the like, and can rotate toward an approaching side or a separating side centering on a joint. 
         [0005]    There is the industrial vehicle having a control device which restricts rotation of the working device toward the approaching side from a restriction position so as to prevent the attachment of the working device from contacting a vehicle body when the industrial vehicle is rotated toward the approaching side (see the Patent Literature 1). 
       PRIOR ART REFERENCE 
     Patent Literature 
       [0006]    Patent Literature 1: the Japanese Patent Laid Open Gazette Hei. 10-8490 
       DISCLOSURE OF INVENTION 
     Problems to Be Solved by the Invention 
       [0007]    However, in the industrial vehicle, the state of rotation of the working device (for example, rotation speed of the working device) is not fixed always. 
         [0008]    In the industrial vehicle, according to the state of rotation of the working device (for example, in the state in which the rotation speed of the working device is high), the working device may be rotated toward the approaching side from the restriction position. 
         [0009]    The present invention is provided in consideration of the conditions as mentioned above, and the purpose of the invention is to provide an industrial vehicle which can prevent certainly rotation of a working device toward an approaching side from a restriction position. 
       Means for Solving the Problems 
       [0010]    The problems to be solved by the present invention have been described above, and subsequently, the means of solving the problems will be described below. 
         [0011]    According to the present invention, an industrial vehicle having a working device which is equipped with an attachment and can be rotated toward an approaching side and a separating side centering on a joint and a control device which restricts rotation of the working device toward the approaching side from a restriction position is characterized in that the control device is configured so that an offset position is set at the separating side from the restriction position, and when the working device rotating toward the approaching side reaches the offset position, an operation stopping the rotation of the working device toward the approaching side is started. 
         [0012]    According to the present invention, an engine and a hydraulic circuit which has a hydraulic pump driven with the engine as a power source, rotates the working device by supplying pressure oil from the hydraulic pump to the working device, and stops the rotation of the working device by stopping the supply of the pressure oil from the hydraulic pump to the working device are provided, and the control device performs correction that the offset position is shifted to the approaching side or the separating side based on an angle speed at the time of rotation of the working device, a temperature of the pressure oil and/or a rotation speed of the engine. 
         [0013]    According to the present invention, the control device is configured so that a restriction range is set at the separating side from the restriction position, and the rotation of the working device is restricted so as not to rotate the working device toward the approaching side when the rotation of the working device is stopped in the restriction range. 
         [0014]    According to the present invention, the control device restricts the rotation of the working device so as not to rotate the working device toward the approaching side when the angle speed at the time of rotation of the working device is not more than a predetermined speed in the restriction range. 
         [0015]    According to the present invention, the control device restricts the rotation of the working device so as not to rotate the working device toward the approaching side when a drop amount of rotation speed of the engine per unit time is not less than a predetermined amount in the restriction range. 
         [0016]    According to the present invention, the control device performs correction of narrowing the restriction range to the approaching side or correction of expanding the restriction range to the separating side based on the rotation speed of the engine. 
         [0017]    According to the present invention, in the state in which the rotation of the working device is restricted so as not to rotate the working device toward the approaching side, when an engine key switch is turned OFF while communication abnormality is detected, the control device releases the state of restricting the rotation of the working device toward the approaching side. 
       Effect of the Invention 
       [0018]    The present invention brings the following effects. 
         [0019]    According to the present invention, the rotation of the working device toward the approaching side from the restriction position can be prevented certainly. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]      FIG. 1  is a side view of an entire configuration of an industrial vehicle according to an embodiment of the present invention. 
           [0021]      FIG. 2  is a block diagram of a configuration of members connected to a control device of the industrial vehicle. 
           [0022]      FIG. 3  is a schematic drawing of a rotation state of a working device of the industrial vehicle. 
           [0023]      FIG. 4  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0024]      FIG. 5  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0025]      FIG. 6  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0026]      FIG. 7  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0027]      FIG. 8  is a flow chart of operation of the industrial vehicle. 
           [0028]      FIG. 9  is a flow chart of operation of the industrial vehicle. 
           [0029]      FIG. 10  is a flow chart of operation of the industrial vehicle. 
           [0030]      FIG. 11  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0031]      FIG. 12  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0032]      FIG. 13  is a diagram of relation between rotation speed of an engine and angle speed of an arm. 
           [0033]      FIG. 14  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0034]      FIG. 15  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0035]      FIG. 16  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
           [0036]      FIG. 17  is a flow chart of operation of the industrial vehicle. 
           [0037]      FIG. 18  is a flow chart of operation of the industrial vehicle. 
           [0038]      FIG. 19  is a flow chart of operation of the industrial vehicle. 
           [0039]      FIG. 20  is a flow chart of operation of the industrial vehicle. 
           [0040]      FIG. 21  is a flow chart of operation of the industrial vehicle. 
           [0041]      FIG. 22  is a flow chart of operation of the industrial vehicle. 
           [0042]      FIG. 23  is a flow chart of operation of the industrial vehicle. 
           [0043]      FIG. 24  is a schematic drawing of a rotation state of the working device of the industrial vehicle. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0044]    Next, a backhoe  1  which is an industrial vehicle according to an embodiment of the present invention is explained. 
         [0045]    Though the backhoe  1  is the embodiment of the industrial vehicle in below explanation, the industrial vehicle is not limited thereto and may alternatively be another agricultural vehicle, construction vehicle, industrial vehicle or the like. For facilitating the explanation, a direction of an arrow F in a drawing is regarded as the front direction of the backhoe  1 , and front, rear, left and right directions when riding on the backhoe  1  and turning to the front are regarded as the front, rear, left and right directions. 
         [0046]    The backhoe  1  described in  FIGS. 1 to 10  is explained. 
         [0047]    As shown in  FIG. 1 or 2 , the backhoe  1  has a traveling device  2 , a revolving device  3 , a working device  4 , a hydraulic circuit  20  and a control device  30 . 
         [0048]    The traveling device  2  of the backhoe  1  has a pair of left and right crawlers  5  and a traveling hydraulic motor (not shown). 
         [0049]    The traveling device  2  is configured so as to make the backhoe  1  (vehicle body) travels forward and rearward and turn by driving the crawlers  5  respectively by the traveling hydraulic motor. 
         [0050]    The revolving device  3  of the backhoe  1  has a revolving base  6 , an operation part  8  and an engine  9 . The revolving device  3  is configured by arranging the operation part  8  and the engine  9  on the revolving base  6 . 
         [0051]    The revolving base  6  is arranged above the traveling device  2  and supported rotatably by the traveling device  2 . The revolving base  6  is configured so as to revolve with respect to the traveling device  2  by a revolving motor (not shown). 
         [0052]    The operation part  8  has various operation instruments (a display device, an operation lever, an engine key switch directing start and stop of the engine  9 , and the like). 
         [0053]    The engine  9  is a power source of various devices of the backhoe  1 . 
         [0054]    The working device  4  of the backhoe  1  is equipped with an attachment and can rotate toward an approaching side and a separating side centering on a joint. 
         [0055]    The working device  4  mainly has a boom  10 , an arm  11 , a bucket  12 , a boom cylinder  13 , an arm cylinder  14 , and an attachment cylinder  15 . 
         [0056]    The boom  10  of the working device  4  of the backhoe  1  is configured so that one of ends of the boom  10  is rotatably supported by a boom fulcrum  10   a,  which is a joint, on a front part of the revolving base  6  of the revolving device  3 . 
         [0057]    The boom  10  is configured so as to be rotated centering on the boom fulcrum  10   a  by a boom cylinder  13  which is driven contractably. The boom  10  is configured so as to be rotated upward (a direction separating the other end of the boom  10  from the revolving base  6  of the revolving device  3 ) when the boom cylinder  13  is extended, and rotated downward (a direction making the other end of the boom  10  close to the revolving base  6  of the revolving device  3 ) when the boom cylinder  13  is contracted. 
         [0058]    The arm  11  of the working device  4  of the backhoe  1  is configured so that one of ends of the arm  11  is rotatably supported by an arm fulcrum  11   a  on the other end of the boom  10 . 
         [0059]    The arm  11  is configured so as to be rotated centering on the arm fulcrum  11   a  by an arm cylinder  14  which is driven contractably. The arm  11  is configured so as to be rotated toward the approaching side (a direction approaching to the revolving device  3 ) when the arm cylinder  14  is extended, and rotated toward the separating side (a direction separating from the revolving device  3 ) when the arm cylinder  14  is contracted. The arm  11  is configured so as to be rotated downward (a direction making the other end of the arm  11  close to the boom  10 ) when the arm cylinder  14  is extended, and rotated upward (a direction separating the other end of the arm  11  from the boom  10 ) when the arm cylinder  14  is contracted. 
         [0060]    The working device  4  of the backhoe  1  is configured so that a sensor  11   b,  which detects a rotation position of the arm  11  (swinging angle of the arm  11 ) and an angle speed at the time of rotation of the arm  11 , is provided at the one of the ends of the arm  11 . The sensor  11   b  is configured by a potentiometer. 
         [0061]    The bucket  12  of the working device  4  of the backhoe  1  is a kind of the attachment. 
         [0062]    The bucket  12  is rotatably supported by an attachment fulcrum  12   a,  which is a joint, on the other end of the arm  11 . 
         [0063]    The bucket  12  is configured so as to be rotated centering on the attachment fulcrum  12   a  by an attachment cylinder  15  which is driven contractably. The bucket  12  is configured so as to be rotated downward (a direction making the other end of the bucket  12  close to the arm  11 ) when the attachment cylinder  15  is extended, and rotated upward (a direction separating the other end of the bucket  12  from the arm  11 ) when the attachment cylinder  15  is contracted. 
         [0064]    As the above, the working device  4  of the backhoe  1  is equipped with the bucket  12  which is the attachment and performs digging of earth and sand and the like with the bucket  12 . 
         [0065]    Other than the bucket  12 , the attachment with which the working device  4  of the backhoe  1  is equipped includes an oil pressure breaker, a fork and the like for example. 
         [0066]    The hydraulic circuit  20  of the backhoe  1  has a hydraulic pump  21 , a switching valve (electromagnetic valve)  22 , a pressure oil thermometer  23  and the like. 
         [0067]    The hydraulic circuit  20  is configured so that pressure oil is supplied from the hydraulic pump  21  to the working device (the boom cylinder  13 , the arm cylinder  14  or the attachment cylinder  15 ) so as to rotate the working device (the boom  10 , the arm  11  or the bucket  12 ), and the supply of the pressure oil from the hydraulic pump  21  to the working device is stopped so as to stop the rotation of the working device. 
         [0068]    The hydraulic circuit  20  performs the supply of the pressure oil from the hydraulic pump  21  to the working device or the stop of the supply of the pressure oil from the hydraulic pump  21  to the working device by the switching valve  22  (ON/OFF operation of the switching valve  22 ). 
         [0069]    The hydraulic pump  21  of the hydraulic circuit  20  is configured so as to be driven with the engine  9  as the power source. 
         [0070]    The pressure oil thermometer  23  of the hydraulic circuit  20  is configured so as to measure temperature of the pressure oil of the hydraulic circuit  20 . 
         [0071]    The control device  30  of the backhoe  1  has an ECU, a hydraulic circuit control unit (not shown) and the like, and is connected to the traveling device  2 , the revolving device  3  (the revolving base  6 , the operation part  8  and the engine  9  of the revolving device  3 ), the working device  4  (the sensor  11   b  of the working device  4 ), the hydraulic circuit  20  (the hydraulic pump  21 , the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and the like. 
         [0072]    The control device  30  is configured so as to control the traveling device  2 , the revolving device  3  (the revolving base  6 , the operation part  8  and the engine  9  of the revolving device  3 ), the working device  4  (the sensor  11   b  of the working device  4 ), the hydraulic circuit  20  (the hydraulic pump  21 , the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and the like. 
         [0073]    Various programs for controlling the traveling device  2 , the revolving device  3  (the revolving base  6 , the operation part  8  and the engine  9  of the revolving device  3 ), the working device  4  (the sensor  11   b  of the working device  4 ), the hydraulic circuit  20  (the hydraulic pump  21 , the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and the like are stored in the control device  30 . The control device  30  can perform predetermined calculations according to these programs and can store results of the calculations and the like. 
         [0074]    The control device  30  of the backhoe  1  is connected to the engine  9 , the various operation instruments of the operation part  8 , the hydraulic circuit  20  (the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and the sensor  11   b  of the working device  4  (see  FIG. 2 ). 
         [0075]    The control device  30  is configured so as to transmit control signals to the engine  9 , the various operation instruments of the operation part  8 , the hydraulic circuit  20  (the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and the sensor  11   b  of the working device  4 , and obtain various kinds of information from the engine  9 , the various operation instruments of the operation part  8 , the hydraulic circuit  20  (the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and the sensor  11   b  of the working device  4 . 
         [0076]    The control device  30  is configured so as to obtain information about the rotation speed of the engine  9  from the engine  9 , information about the temperature of the pressure oil of the hydraulic circuit  20  from the pressure oil thermometer  23 , information about the rotation position of the arm  11  from the sensor  11   b  of the working device  4 , and information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4 . 
         [0077]    The control device  30  of the backhoe  1  stores restriction position information, offset position information and restriction releasing position information. 
         [0078]    The restriction position information of the control device  30  of the backhoe  1  concerns to a restriction position A restricting rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0079]    For preventing the working device  4  (the bucket  12  of the working device  4 ) from contacting the vehicle body (the boom  10  of the working device  4 ) when the working device  4  (the arm  11  of the working device  4 ) is rotated toward the approaching side, the control device  30  is configured so as to restrict the rotation of the working device  4  (the arm  11  of the working device  4 ) so that the working device  4  (the arm  11  of the working device  4 ) is not rotated toward the approaching side from the restriction position A (see  FIG. 3 ). 
         [0080]    The backhoe  1  is configured so that the working device  4  (the arm  11  of the working device  4 ) can be rotated toward the separating side even if the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted. 
         [0081]    The offset position information of the control device  30  of the backhoe  1  concerns to an offset position B at which an operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) is started in the case in which the rotation of the working device  4  toward the approaching side is restricted. 
         [0082]    The control device  30  is configured so that the offset position B is set closer to the separating side from the restriction position A. 
         [0083]    The control device  30  is configured so that the operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is started when the working device  4  (the arm  11  of the working device  4 ) rotating toward the approaching side (see  FIG. 4 ). 
         [0084]    The control device  30  is configured so that when the working device  4  (the arm  11  of the working device  4 ) rotating toward the approaching side reaches the offset position, the switching valve  22  of the hydraulic circuit  20  is turned ON so as to stop the supply of the pressure oil from the hydraulic pump  21  to the working device  4  (the arm  11  of the working device  4 ), whereby the operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) is started. 
         [0085]    The control device  30  of the backhoe  1  is configured to perform correction that the offset position B set actually is shifted to the approaching side or the separating side based on various kinds of information obtained from the hydraulic circuit  20  (the switching valve  22  and the pressure oil thermometer  23  of the hydraulic circuit  20 ) and/or the sensor  11   b  of the working device  4  (see  FIGS. 5 and 6 ). 
         [0086]    The control device  30  of the backhoe  1  is configured to perform correction that the offset position B set actually is shifted to the approaching side or the separating side based on the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ), the temperature of the pressure oil of the hydraulic circuit  20 , and/or the rotation speed of the engine  9 . 
         [0087]    At this time, the control device  30  refers to the angle speed of the working device  4  (the arm  11  of the working device  4 ), the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the offset position B, and sets the new offset position B at the approaching side or the separating side from the offset position B set actually, thereby performing the correction that the offset position B set actually is shifted to the approaching side or the separating side. 
         [0088]    The control device  30  is configured to perform correction that the offset position B set actually is shifted to the separating side when the working device  4  (the arm  11  of the working device  4 ) is relatively high, the temperature of the pressure oil of the hydraulic circuit  20  is relatively low, and/or the rotation speed of the engine  9  is relatively high. The control device  30  is configured to perform correction that the offset position B set actually is shifted to the approaching side when the working device  4  (the arm  11  of the working device  4 ) is relatively low, the temperature of the pressure oil of the hydraulic circuit  20  is relatively high, and/or the rotation speed of the engine  9  is relatively low. 
         [0089]    The restriction releasing position information of the control device  30  of the backhoe  1  concerns to a restriction releasing position C at which restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is released. 
         [0090]    The control device  30  is configured so that the restriction releasing position C is set closer to the separating side from the offset position B. 
         [0091]    The control device  30  is configured so that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted, when the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C, the restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is released (see  FIG. 7 ). 
         [0092]    The control device  30  of the backhoe  1  is configured to detect communication abnormality between the control device  30  and the devices of the backhoe  1  connected to the control device  30  (the traveling device  2 , the revolving device  3 , the working device  4  and the hydraulic circuit  20 ) (CAN communication abnormality). 
         [0093]    The control device  30  of the backhoe  1  is configured to detect turning OFF of the engine key switch of the operation part  8  when the engine key switch of the operation part  8  is turned OFF (operation of the engine  9  is stopped). 
         [0094]    The control device  30  is configured so that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted, when the engine key switch of the operation part  8  is turned OFF (the operation of the engine  9  is stopped) while the communication abnormality (CAN communication abnormality) is detected, the state in which rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is released. 
         [0095]    Next, referring to  FIG. 8 , a series of operation in the backhoe  1  that the control device  30  stops the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the working device  4  (the arm  11  of the working device  4 ) rotating toward the approaching side reaches the offset position B is explained. 
         [0096]    As shown in  FIG. 8 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9 , the temperature of the pressure oil of the hydraulic circuit  20  and the angle speed of the arm  11  of the working device  4  at the time of rotation (step S 1 ). 
         [0097]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9 , information about the temperature of the pressure oil of the hydraulic circuit  20  from the pressure oil thermometer  23  of the pressure oil of the hydraulic circuit  20 , or information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the rotation speed of the engine  9 , the temperature of the pressure oil of the hydraulic circuit  20  and the angle speed of the arm  11  of the working device  4  at the time of rotation. 
         [0098]    After detecting the rotation speed of the engine  9 , the temperature of the pressure oil of the hydraulic circuit  20  and the angle speed of the arm  11  of the working device  4  at the time of rotation (step S 1 ), the control device  30  shifts to a step S 2 . 
         [0099]    Next, based on the angle speed of the working device  4  (the arm  11  of the working device  4 ), the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9 , the control device  30  of the backhoe  1  performs the correction that the offset position B is shifted to the approaching side or the separating side from the offset position set actually (step S 2 ). 
         [0100]    At this time, the control device  30  refers to the angle speed of the working device  4  (the arm  11  of the working device  4 ) at the time of rotation, the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9  and the map stored previously in the control device  30  so as to calculate the correction value for correcting the offset position B. 
         [0101]    Subsequently, the control device  30  sets the new offset position B at the approaching side or the separating side from the offset position B set actually based on the calculated correction value for correcting the offset position B. 
         [0102]    As the above, based on the angle speed of the working device  4  (the arm  11  of the working device  4 ), the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9 , the control device  30  performs the correction that the offset position is shifted to the approaching side or the separating side from the offset position B set actually (see  FIG. 5 or 6 ). 
         [0103]    After performing the correction that the offset position B set actually is shifted to the approaching side or the separating side from the offset position set actually based on the angle speed of the working device  4  (the arm  11  of the working device  4 ), the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9  (step S 2 ), the control device  30  shifts to a step S 3 . 
         [0104]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side (step S 3 ). 
         [0105]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side. 
         [0106]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side (step S 3 ), the control device  30  shifts to a step S 4 . 
         [0107]    Next, based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side detected in the step S 3 , the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side reaches the offset position B or not (step S 4 ). 
         [0108]    When is judged not to be the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side is judged not to reach the offset position B, the control device  30  shifts to the step 
         [0109]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side is judged to reach the offset position B (see  FIG. 4 ), the control device  30  shifts to a step S 5 . 
         [0110]    Next, the control device  30  of the backhoe  1  starts the operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (step S 5 ). 
         [0111]    At this time, when the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side is rotated to the offset position (see  FIG. 4 ), the control device  30  turns ON the switching valve  22  of the hydraulic circuit  20  is so as to stop the supply of the pressure oil from the hydraulic pump  21  to the working device  4  (the arm  11  of the working device  4 ), whereby the operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) is started. 
         [0112]    Accordingly, in the backhoe  1 , when the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side is rotated to the offset position, the control device  30  performs the series of operation including starting for stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0113]    As the above, in the backhoe  1  in which the control device  30  starts the operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the offset position B is set closer to the separating side from the restriction position A and the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side is rotated to the offset position, the operation stopping the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is started when the working device  4  (the arm  11  of the working device  4 ) rotated toward the approaching side is rotated to the offset position B which is set closer to the separating side from the restriction position A. 
         [0114]    Then, according to the backhoe  1 , the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side from the restriction position A can be prevented certainly. 
         [0115]    As the above, in the backhoe  1  in which the control device  30  performs the correction that the offset position B is shifted to the approaching side or the separating side based on the angle speed of the working device  4  (the arm  11  of the working device  4 ) at the time of the rotation, the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9 , the correction that the offset position B is shifted to the approaching side or the separating side so as to stop the working device  4  (the arm  11  of the working device  4 ) at the restriction position A (near the restriction position A) can be performed corresponding to the angle speed of the working device  4  (the arm  11  of the working device  4 ) at the time of the rotation, the temperature of the pressure oil of the hydraulic circuit  20  and/or the rotation speed of the engine  9 . 
         [0116]    Then, according to the backhoe  1 , accuracy of stopping the working device  4  (the arm  11  of the working device  4 ) at the restriction position A (near the restriction position A) can be improved. 
         [0117]    At this time, for example, at the time of high idling of the engine  9 , when the working device  4  (the arm  11  of the working device  4 ) is operated at low speed, the control device  30  of the backhoe  1  performs the correction that the offset position B is shifted to the approaching side from the actual offset position B while weaving the angle speed of the working device  4  (the arm  11  of the working device  4 ) at the time of the rotation into the rotation speed of the engine  9  so as to prevent the working device  4  (the arm  11  of the working device  4 ) from being stopped at a position far from the restriction position A. 
         [0118]    Accordingly, in the backhoe  1 , at the time of high idling of the engine  9 , when the working device  4  (the arm  11  of the working device  4 ) is operated at low speed, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being stopped at a position far from the restriction position A. 
         [0119]    Next, referring to  FIG. 9 , a series of operation in the backhoe  1  is explained that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C, the control device  30  releases the restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0120]    As shown in  FIG. 9 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side from the sensor  11   b  of the working device  4  (step S 11 ). 
         [0121]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side. 
         [0122]    In the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, after detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side (step S 11 ), the control device  30  shifts to a step S 12 . 
         [0123]    Next, based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side detected in the step S 11 , the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C or not (step S 12 ). 
         [0124]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side is judged not to reach the restriction releasing position C, the control device  30  shifts to the step S 11 . 
         [0125]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side is judged to reach the restriction releasing position C (see  FIG. 7 ), the control device  30  shifts to a step S 13 . 
         [0126]    Next, the control device  30  of the backhoe  1  releases the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (step S 13 ). 
         [0127]    Accordingly, in the state of the backhoe  1  in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C, the control device  30  releases the restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0128]    As the above, in the backhoe  1  configured so that the control device  30  releases the restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C in the state in which the restriction releasing position C is set closer to the separating side from the offset position B and the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, by rotating the working device  4  (the arm  11  of the working device  4 ) toward the separating side to the restriction releasing position C in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side can be released. 
         [0129]    Then, according to the backhoe  1 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted can be released by easy operation of the working device  4 . 
         [0130]    Next, referring to  FIG. 10 , a series of operation in the backhoe  1  is explained that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the engine key switch of the operation part  8  is turned OFF (the operation of the engine is stopped) while the communication abnormality (CAN communication abnormality) is detected, the control device  30  releases the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0131]    As shown in  FIG. 10 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the control device  30  of the backhoe  1  detects the communication abnormality (CAN communication abnormality) between the control device  30  and the devices of the backhoe  1  connected to the control device  30  (step S 15 ). After detecting the communication abnormality (CAN communication abnormality) in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (step S 15 ), the control device  30  shifts to a step S 16 . 
         [0132]    Next, the control device  30  of the backhoe  1  detects turning OFF of the engine key switch of the operation part  8  (stopping of the engine  9 ) (step S 16 ). 
         [0133]    After detecting the turning OFF of the engine key switch of the operation part  8  (step S 16 ), the control device  30  shifts to a step S 17 . 
         [0134]    Next, the control device  30  of the backhoe  1  releases the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (step S 17 ). 
         [0135]    Accordingly, in the state of the backhoe  1  in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the engine key switch of the operation part  8  is turned OFF (the operation of the engine  9  is stopped) while the communication abnormality (CAN communication abnormality) is detected, the control device  30  releases the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0136]    As the above, in the backhoe  1  configured so that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the engine key switch of the operation part  8  is turned OFF (the operation of the engine is stopped) while the communication abnormality (CAN communication abnormality) is detected, the control device  30  releases the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, by turning OFF the engine key switch of the operation part  8  while the communication abnormality (CAN communication abnormality) is detected, the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted can be released. 
         [0137]    Then, according to the backhoe  1 , the state that each part of the backhoe  1  cannot be operated at the time of the communication abnormality (CAN communication abnormality) and the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side cannot be released can be prevented. 
         [0138]    In the backhoe  1 , the plurality of the restriction position information which are different from each other at the position restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side are stored in the control device  30 , and the restriction position information can be selected from the plurality of the restriction position information by operating the operation instruments of the operation part  8  so as to set the restriction position A. 
         [0139]    In the backhoe  1 , the restriction position A can be set regardless of the rotation position of the working device  4  (the arm  11  of the working device  4 ) (even if the rotation position of the arm  11  of the working device  4  is closer to the offset position B). 
         [0140]    Next, the backhoe  1  described in  FIGS. 9 and 11 to 24  is explained. 
         [0141]    In the explanation of the backhoe  1  described in  FIGS. 9 and 11 to 24 , parts of similar configuration to the backhoe  1  described in  FIGS. 1 to 9  are omitted and parts different from the backhoe  1  described in  FIGS. 1 to 9  are explained mainly. 
         [0142]    The restriction position information, the restriction releasing position information and restriction range information are stored in the control device  30  of the backhoe  1 . 
         [0143]    The restriction range information of the control device  30  of the backhoe  1  concerns to a restriction range D. 
         [0144]    The control device  30  is configured so that the restriction range D is set at the separating side from the restriction position A (see  FIG. 11 ). 
         [0145]    The control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D. 
         [0146]    The control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than a predetermined speed in the restriction range D (see  FIG. 12 ). 
         [0147]    The control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when drop amount of rotation speed of the engine  9  per unit time is not less than a predetermined amount in the restriction range D. 
         [0148]    The predetermined speed of the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is the rotation speed of the working device  4  (the arm  11  of the working device  4 ) in the state before increasing the speed suddenly and rotating the working device  4  (the arm  11  of the working device  4 ) in which the working device  4  (the arm  11  of the working device  4 ) may be rotated toward the approaching side from the restriction position A by increasing the speed suddenly and rotating the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (for example, the speed at which the arm  11  of the working device  4  is substantially stopped). 
         [0149]    The predetermined amount of the drop amount of rotation speed of the engine  9  per unit time is the drop amount of rotation speed of the engine  9  at the moment of starting the rotation (just after starting the rotation) in the state in which the working device  4  (the arm  11  of the working device  4 ) may be rotated toward the approaching side from the restriction position A by increasing the speed suddenly and rotating the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (for example, the drop amount of rotation speed of the engine  9  is 50 min-1) (see  FIG. 13 ). In the backhoe  1 , when the switching valve  22  is switched by operating the operation instruments of the operation part  8 , hydraulic load of the pressure oil of the hydraulic circuit  20  is increased. As a result, in the backhoe  1 , load of the engine  9  driving the hydraulic pump  21  is increased and the rotation speed of the engine  9  is dropped suddenly. Just after it, in the backhoe  1 , pressure of the pressure oil of the hydraulic circuit  20  is increased and the rotation of the working device  4  is started. 
         [0150]    The control device  30  of the backhoe  1  is configured to perform correction of narrowing the restriction range D set actually to the approaching side or correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0151]    The control device  30  of the backhoe  1  is configured by setting the restriction releasing position C at a boundary part between the restriction range D and the outside of the restriction range D at the separating side. 
         [0152]    The control device  30  of the backhoe  1  is configured so that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the working device  4  (the arm  11  of the working device  4 ) rotating toward the separating side reaches the restriction releasing position C, state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted is released (see  FIG. 16 ). 
         [0153]    Next, referring to  FIG. 17 , a series of operation in the backhoe  1  is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0154]    As shown in  FIG. 17 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 21 ). 
         [0155]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0156]    After detecting the rotation speed of the engine  9  (step S 21 ), the control device  30  shifts to a step S 22 . 
         [0157]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 22 ). 
         [0158]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0159]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0160]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0161]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 22 ), the control device  30  shifts to a step S 23 . 
         [0162]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 23 ). At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0163]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 23 ), the control device  30  shifts to a step S 24 . 
         [0164]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 23  (step S 24 ). 
         [0165]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step S 21 . 
         [0166]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 25 . 
         [0167]    Next, the control device  30  of the backhoe  1  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not (step S 25 ). 
         [0168]    At this time, the control device  30  obtains information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0169]    Then, the control device  30  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not based on the detected angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0170]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged not to be stopped in the restriction range D, the control device  30  shifts to a step S 26 . When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged to be stopped in the restriction range D (see  FIG. 12 ), the control device  30  shifts to a step S 28 . 
         [0171]    Next, the control device  30  of the backhoe  1  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D or not (step S 26 ). 
         [0172]    At this time, the control device  30  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D or not based on the angle speed at the time of rotation of the arm  11  of the working device  4  detected in the step S 25 . 
         [0173]    When the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is judged to be more than the predetermined speed in the restriction range D, the control device  30  shifts to a step S 27 . 
         [0174]    When the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is judged not to be more than the predetermined speed in the restriction range D, the control device  30  shifts to the step S 28 . 
         [0175]    Next, the control device  30  of the backhoe  1  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not (step S 27 ). 
         [0176]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0177]    Then, the control device  30  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not based on the detected rotation speed of the engine  9  (see  FIG. 13 ). 
         [0178]    When the drop amount of rotation speed of the engine  9  per unit time is judged to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 23 . 
         [0179]    When the drop amount of rotation speed of the engine  9  per unit time is judged not to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 28 . 
         [0180]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 28 ). 
         [0181]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0182]    As the above, in the backhoe  1  in which the control device  30  is configured so that the restriction range D is set at the separating side from the restriction position A and the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D when the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped, the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D. 
         [0183]    Then, according to the backhoe  1 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) at the separating side from the restriction position A (near the separating side from the restriction position A), when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being rotated toward the approaching side from the restriction position A. 
         [0184]    As the above, in the backhoe  1  in which the control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D, he rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the state in which the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D. 
         [0185]    Then, according to the backhoe  1 , in the state in which the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed, when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side while increasing the speed, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being rotated toward the approaching side from the restriction position A. 
         [0186]    As the above, in the backhoe  1  in which the control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D, the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D. 
         [0187]    As the above, in the backhoe  1 , the timing of restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is judged from the drop amount of rotation speed of the engine  9  caused by increase of the hydraulic load. Accordingly, in comparison with the configuration of performing the judgement from the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ), the judgement of restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side can be performed more quickly. 
         [0188]    Then, according to the backhoe  1 , in comparison with the configuration of performing the judgement the timing of restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) from the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ), when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side while increasing the speed, the working device  4  (the arm  11  of the working device  4 ) can be prevented more certainly from being rotated toward the approaching side from the restriction position A. 
         [0189]    As the above, in the backhoe  1  in which the control device  30  is configured so as to performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9 , the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side can be performed corresponding to the rotation speed of the engine  9  so as to stop the working device  4  (the arm  11  of the working device  4 ) at the restriction position A (near the restriction position A). 
         [0190]    Then, according to the backhoe  1 , accuracy of stopping the working device  4  (the arm  11  of the working device  4 ) at the restriction position A (near the restriction position A) can be improved. 
         [0191]    Next, referring to  FIG. 9 , a series of operation in the backhoe  1  is explained that in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the working device  4  (the arm  11  of the working device  4 ) is rotated to the restriction releasing position C, the control device  30  releases the restriction of the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0192]    As shown in  FIG. 9 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side from the sensor  11   b  of the working device  4  (step S 11 ). 
         [0193]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side from the sensor  11   b  of the working device  4  in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (step S 11 ), the control device  30  shifts to the step S 12 . 
         [0194]    Next, based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side detected in the step S 11 , the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C or not (step S 12 ). 
         [0195]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side is judged not to reach the restriction releasing position C, the control device  30  shifts to the step S 11 . 
         [0196]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side is judged to reach the restriction releasing position C (see  FIG. 16 ), the control device  30  shifts to the step S 13 . 
         [0197]    Next, the control device  30  of the backhoe  1  releases the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side (step S 13 ). 
         [0198]    Accordingly, in the state of the backhoe  1  in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C, the control device  30  releases the restriction of rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side. 
         [0199]    As the above, in the backhoe  1  in which the control device  30  is configured so that the restriction range D is set at the separating side from the restriction position A, and in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, when the working device  4  (the arm  11  of the working device  4 ) rotated toward the separating side reaches the restriction releasing position C, the restriction of the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is released, by rotating the working device  4  (the arm  11  of the working device  4 ) toward the separating side reaches the restriction releasing position C in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the restriction of the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side can be released. 
         [0200]    Then, according to the backhoe  1 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side, the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is restricted can be released by easy operation of the working device  4 . 
         [0201]    Next, referring to  FIG. 18 , a series of operation in the backhoe  1  of another embodiment is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0202]    As shown in  FIG. 18 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 31 ). 
         [0203]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0204]    After detecting the rotation speed of the engine  9  (step S 31 ), the control device  30  shifts to a step S 32 . 
         [0205]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 32 ). 
         [0206]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0207]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0208]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0209]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 32 ), the control device  30  shifts to a step S 33 . 
         [0210]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 33 ). 
         [0211]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0212]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 33 ), the control device  30  shifts to a step S 34 . 
         [0213]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 33  (step S 34 ). 
         [0214]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step S 31 . 
         [0215]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 35 . 
         [0216]    Next, the control device  30  of the backhoe  1  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not (step S 35 ). 
         [0217]    At this time, the control device  30  obtains information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0218]    Then, the control device  30  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not based on the detected angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0219]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged not to be stopped in the restriction range D, the control device  30  shifts to the step S 33 . 
         [0220]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged to be stopped in the restriction range D (see  FIG. 12 ), the control device  30  shifts to a step S 38 . 
         [0221]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 38 ). 
         [0222]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0223]    As the above, in the backhoe  1  in which the control device  30  is configured so that the restriction range D is set at the separating side from the restriction position A and the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D when the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped, the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D. 
         [0224]    Then, according to the backhoe  1 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) in the restriction range D, when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being rotated toward the approaching side from the restriction position A. 
         [0225]    Next, a series of operation in the backhoe  1  of another embodiment is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0226]    As shown in  FIG. 19 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 41 ). 
         [0227]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0228]    After detecting the rotation speed of the engine  9  (step S 41 ), the control device  30  shifts to a step S 42 . 
         [0229]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 42 ). 
         [0230]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0231]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0232]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0233]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 42 ), the control device  30  shifts to a step S 43 . 
         [0234]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 43 ). 
         [0235]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0236]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 43 ), the control device  30  shifts to a step S 44 . 
         [0237]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 43  (step S 44 ). 
         [0238]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step S 41 . 
         [0239]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 46 . 
         [0240]    Next, the control device  30  of the backhoe  1  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D or not (step S 46 ). 
         [0241]    At this time, the control device  30  obtains information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0242]    Then, the control device  30  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) in the restriction range D is not more than the predetermined amount or not based on the detected angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0243]    When the drop amount of rotation speed of the engine  9  per unit time is judged to be more than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 43 . 
         [0244]    When the drop amount of rotation speed of the engine  9  per unit time is judged not to be more than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 48 . 
         [0245]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 48 ). 
         [0246]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0247]    As the above, in the backhoe  1  in which the control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D, he rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the state in which the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D. 
         [0248]    Then, according to the backhoe  1 , in the state in which the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed, when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side while increasing the speed, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being rotated toward the approaching side from the restriction position A. 
         [0249]    Next, a series of operation in the backhoe  1  of another embodiment is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0250]    As shown in  FIG. 20 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 51 ). 
         [0251]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0252]    After detecting the rotation speed of the engine  9  (step S 51 ), the control device  30  shifts to a step S 52 . 
         [0253]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 52 ). 
         [0254]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0255]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0256]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0257]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 52 ), the control device  30  shifts to a step S 53 . 
         [0258]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 53 ). 
         [0259]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0260]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 53 ), the control device  30  shifts to a step SM. 
         [0261]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 53  (step S 54 ). 
         [0262]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step SM. When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 57 . 
         [0263]    Next, the control device  30  of the backhoe  1  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not (step S 57 ). 
         [0264]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0265]    Then, the control device  30  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not based on the detected rotation speed of the engine  9  (see  FIG. 13 ). 
         [0266]    When the drop amount of rotation speed of the engine  9  per unit time is judged to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 53 . 
         [0267]    When the drop amount of rotation speed of the engine  9  per unit time is judged not to be less than the predetermined amount in the restriction range D, the control device  30  shifts to a step S 58 . 
         [0268]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 58 ). 
         [0269]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0270]    As the above, in the backhoe  1  in which the control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D, the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D. 
         [0271]    As the above, in the backhoe  1 , the timing of restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side is judged from the drop amount of rotation speed of the engine  9 . Accordingly, in comparison with the configuration of performing the judgement from the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ), the judgement of restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side can be performed more quickly. 
         [0272]    Then, according to the backhoe  1 , in comparison with the configuration of performing the judgement the timing of restricting the rotation of the working device  4  (the arm  11  of the working device  4 ) from the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ), when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side while increasing the speed, the working device  4  (the arm  11  of the working device  4 ) can be prevented more certainly from being rotated toward the approaching side from the restriction position A. 
         [0273]    Next, a series of operation in the backhoe  1  of another embodiment is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0274]    As shown in  FIG. 21 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 61 ). 
         [0275]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0276]    After detecting the rotation speed of the engine  9  (step S 61 ), the control device  30  shifts to a step S 62 . 
         [0277]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 62 ). 
         [0278]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0279]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0280]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0281]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 62 ), the control device  30  shifts to a step S 63 . 
         [0282]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 63 ). 
         [0283]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0284]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 63 ), the control device  30  shifts to a step S 64 . 
         [0285]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 63  (step S 64 ). 
         [0286]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step S 61 . 
         [0287]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 65 . 
         [0288]    Next, the control device  30  of the backhoe  1  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not (step S 65 ). 
         [0289]    At this time, the control device  30  obtains information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0290]    Then, the control device  30  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not based on the detected angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0291]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged not to be stopped in the restriction range D, the control device  30  shifts to a step S 66 . 
         [0292]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged to be stopped in the restriction range D (see  FIG. 12 ), the control device  30  shifts to a step S 68 . 
         [0293]    Next, the control device  30  of the backhoe  1  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D or not (step S 66 ). 
         [0294]    At this time, the control device  30  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D or not based on the angle speed at the time of rotation of the arm  11  of the working device  4  detected in the step S 65 . 
         [0295]    When the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is judged to be more than the predetermined speed in the restriction range D, the control device  30  shifts to a step S 63 . 
         [0296]    When the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is judged not to be more than the predetermined speed in the restriction range D, the control device  30  shifts to the step S 68 . 
         [0297]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 68 ). 
         [0298]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0299]    As the above, in the backhoe  1  in which the control device  30  is configured so that the restriction range D is set at the separating side from the restriction position A and the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D when the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped, the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D. 
         [0300]    Then, according to the backhoe  1 , in the state in which the rotation of the working device  4  (the arm  11  of the working device  4 ) in the restriction range D, when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being rotated toward the approaching side from the restriction position A. 
         [0301]    As the above, in the backhoe  1  in which the control device  30  is configured so that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side when the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D, he rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the state in which the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D. 
         [0302]    Then, according to the backhoe  1 , in the state in which the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed, when the working device  4  (the arm  11  of the working device  4 ) is rotated suddenly toward the approaching side while increasing the speed, the working device  4  (the arm  11  of the working device  4 ) can be prevented from being rotated toward the approaching side from the restriction position A. 
         [0303]    Next, a series of operation in the backhoe  1  of another embodiment is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0304]    As shown in  FIG. 22 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 71 ). 
         [0305]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0306]    After detecting the rotation speed of the engine  9  (step S 71 ), the control device  30  shifts to a step S 72 . 
         [0307]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 72 ). 
         [0308]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0309]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0310]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0311]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 72 ), the control device  30  shifts to a step S 73 . 
         [0312]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 73 ). 
         [0313]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0314]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 73 ), the control device  30  shifts to a step S 74 . 
         [0315]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 73  (step S 74 ). 
         [0316]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step S 71 . 
         [0317]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 75 . 
         [0318]    Next, the control device  30  of the backhoe  1  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not (step S 75 ). 
         [0319]    At this time, the control device  30  obtains information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0320]    Then, the control device  30  judges whether the rotation of the working device  4  (the arm  11  of the working device  4 ) is stopped in the restriction range D or not based on the detected angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0321]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged not to be stopped in the restriction range D, the control device  30  shifts to a step S 77 . 
         [0322]    When the rotation of the working device  4  (the arm  11  of the working device  4 ) is judged to be stopped in the restriction range D, the control device  30  shifts to a step S 78 . 
         [0323]    Next, the control device  30  of the backhoe  1  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not (step S 77 ). 
         [0324]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0325]    Then, the control device  30  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not based on the detected rotation speed of the engine  9  (see  FIG. 13 ). 
         [0326]    When the drop amount of rotation speed of the engine  9  per unit time is judged to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 73 . 
         [0327]    When the drop amount of rotation speed of the engine  9  per unit time is judged not to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 78 . 
         [0328]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 78 ). 
         [0329]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0330]    Next, a series of operation in the backhoe  1  of another embodiment is explained that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D. 
         [0331]    As shown in  FIG. 23 , the control device  30  of the backhoe  1  detects the rotation speed of the engine  9  (step S 81 ). 
         [0332]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . After detecting the rotation speed of the engine  9  (step S 81 ), the control device  30  shifts to a step S 82 . 
         [0333]    Next, the control device  30  of the backhoe  1  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 82 ). 
         [0334]    At this time, the control device  30  refers to the rotation speed of the engine  9  and a map stored previously in the control device  30  so as to calculate a correction value for correcting the restriction range D. 
         [0335]    Then, based on the calculated correction value for correcting the restriction range D, the control device  30  sets the new restriction range D which is narrowed to the approaching side or expanded to the separating side from the restriction range D set actually. 
         [0336]    Accordingly, the control device  30  performs the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (see  FIG. 14 or 15 ). 
         [0337]    After performing the correction of narrowing the restriction range D set actually to the approaching side or the correction of expanding the restriction range D to the separating side based on the rotation speed of the engine  9  (step S 82 ), the control device  30  shifts to a step S 83 . 
         [0338]    Next, the control device  30  of the backhoe  1  detects the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 83 ). 
         [0339]    At this time, the control device  30  obtains information about the rotation position of the working device  4  (the arm  11  of the working device  4 ) from the sensor  11   b  of the working device  4  so as to detect the rotation position of the working device  4  (the arm  11  of the working device  4 ). 
         [0340]    After detecting the rotation position of the working device  4  (the arm  11  of the working device  4 ) (step S 83 ), the control device  30  shifts to a step S 84 . 
         [0341]    Next, the control device  30  of the backhoe  1  judges whether the rotation position of the working device  4  (the arm  11  of the working device  4 ) is in the restriction range D or not based on the rotation position of the working device  4  (the arm  11  of the working device  4 ) detected in the step S 83  (step S 84 ). 
         [0342]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged not to be in the restriction range D, the control device  30  shifts to the step S 81 . 
         [0343]    When the rotation position of the working device  4  (the arm  11  of the working device  4 ) is judged to be in the restriction range D (see  FIG. 16 ), the control device  30  shifts to a step S 86 . 
         [0344]    Next, the control device  30  of the backhoe  1  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) is not more than the predetermined speed in the restriction range D or not (step S 86 ). 
         [0345]    At this time, the control device  30  obtains information about the angle speed at the time of rotation of the arm  11  from the sensor  11   b  of the working device  4  so as to detect the angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0346]    Then, the control device  30  judges whether the angle speed at the time of rotation of the working device  4  (the arm  11  of the working device  4 ) in the restriction range D is not more than the predetermined amount or not based on the detected angle speed at the time of rotation of the arm  11  of the working device  4 . 
         [0347]    When the drop amount of rotation speed of the engine  9  per unit time is judged to be more than the predetermined amount in the restriction range D, the control device  30  shifts to a step S 87 . 
         [0348]    When the drop amount of rotation speed of the engine  9  per unit time is judged not to be more than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 88 . 
         [0349]    Next, the control device  30  of the backhoe  1  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not (step S 87 ). 
         [0350]    At this time, the control device  30  obtains information about the rotation speed of the engine  9  from the engine  9  so as to detect the rotation speed of the engine  9 . 
         [0351]    Then, the control device  30  judges whether the drop amount of rotation speed of the engine  9  per unit time is not less than the predetermined amount in the restriction range D or not based on the detected rotation speed of the engine  9  (see  FIG. 13 ). 
         [0352]    When the drop amount of rotation speed of the engine  9  per unit time is judged to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 83 . 
         [0353]    When the drop amount of rotation speed of the engine  9  per unit time is judged not to be less than the predetermined amount in the restriction range D, the control device  30  shifts to the step S 88 . 
         [0354]    Next, the control device  30  of the backhoe  1  restricts the rotation of the working device  4  (the arm  11  of the working device  4 ) so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D (step S 88 ). 
         [0355]    Accordingly, the series of operation in the backhoe  1  that the rotation of the working device  4  (the arm  11  of the working device  4 ) is restricted so as not to rotate the working device  4  (the arm  11  of the working device  4 ) toward the approaching side in the restriction range D of the backhoe  1  is performed. 
         [0356]    The backhoe  1  may be configured so that information about the restriction position, information about the offset position, information about the restriction releasing position and information about the restriction range are stored in the control device  30 . 
         [0357]    At this time, the control device  30  is configured so that the restriction range D is set at the separating side from the restriction position A and the offset position B (see  FIG. 24 ). 
       INDUSTRIAL APPLICABILITY 
       [0358]    The present invention can be used for an art of an industrial vehicle. 
       DESCRIPTION OF NOTATIONS 
       [0000]    
       
           1  backhoe 
           2  traveling device 
           3  revolving device 
           4  working device 
           9  engine 
           10  boom 
           11  arm 
           12  bucket 
           11   a  arm fulcrum 
           11   b  sensor 
           20  hydraulic circuit 
           21  hydraulic pump 
           22  switching valve 
           23  pressure oil thermometer 
           30  control device 
         A restriction position 
         B offset position 
         C restriction releasing position 
         D restriction range