Patent Publication Number: US-10329736-B2

Title: Grip heater apparatus for construction machine

Description:
TECHNICAL FIELD 
     The present invention relates to a construction machine such as a hydraulic excavator. 
     BACKGROUND ART 
     Generally, a construction machine such as a hydraulic excavator includes a self-propelled lower track structure, an upper swing structure provided in an upper portion of the lower track structure in such a manner as to be swingable, and a front work device provided in a front portion of the upper swing structure in such a manner as to be capable of being elevated. 
     Further, the upper swing structure substantially includes a swing frame that serves as a base, an operating room located on the left side of the front work device and provided on the swing frame, a counterweight provided in a rear end portion of the swing frame and maintaining a weight balance with the front work device, an engine mounted in the swing frame, and an exterior cover that covers mounted devices such as a hydraulic pump. An operator seat on which an operator is seated, left and right travel lever pedals for operating the lower track structure, left and right operation levers for operating the front work device, and the like are arranged in the operating room. 
     Types of the operating room of the construction machine are roughly classified into an open canopy type and a closed cab type. Patent Document 1, for example, discloses a construction machine with a canopy type operating room. Patent Document 2, for example, discloses a construction machine with a cab type operating room. 
     In a case of a hydraulic excavator equipped with the canopy type operating room, the operator seated on the operator seat operates the left and right operation levers while directly viewing the front work device and can carry out earth and sand excavation work or the like using the front work device. In a case of a hydraulic excavator equipped with the cab type operating room, the operator seated on the operator seat operates the left and right operation levers while viewing the front work device through a windshield on a front surface of the cab and can carry out earth and sand excavation work or the like using the front work device. 
     PRIOR ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: JP-2007-62506-A 
     Patent Document 2: JP-2007-50785-A 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     However, in the case of the hydraulic excavator equipped with the canopy type operating room described in, for example, Patent Document 1, an interior of the operating room is exposed to outside air, with the result that operator&#39;s hands get cold and the operator finds it difficult to carry out fine operation at a time of work in a cold region. 
     On the other hand, in the case of the hydraulic excavator equipped with the cab type operating room described in, for example, Patent Document 2, it is unlikely that operator&#39;s hands get cold in a normal state since the cab closes off the interior of the operating room from outside air. However, when the operator carries out work in a state that a cab door is left open in order to secure, for example, a wide field of vision of surroundings of a machine body, the interior of the operating room is exposed to the outdoor air, the operator&#39;s hands get cold, and operability is affected similarly to the case of the canopy type. 
     The present invention has been achieved in the light of the problems described above, and an object thereof is to provide a grip heater apparatus for a construction machine that can improve operability by heating the grip portions of left and right operating levers and maintaining a favorable operating environment for the left and right operating levers when work is carried out in a cold region and the operator&#39;s hands get cold. 
     Means for Solving the Problems 
     To attain the object, the present invention provides a grip heater apparatus for a construction machine, the grip heater apparatus being provided in the construction machine that includes: a self-propelled lower track structure; an upper swing structure provided in an upper portion of the lower track structure in such a manner as to be swingable; a front work device provided in a front portion of the upper swing structure in such a manner as to be capable of being elevated; an engine mounted in the upper swing structure; a hydraulic pump driven by the engine; a plurality of hydraulic actuators driven by a hydraulic fluid supplied from the hydraulic pump, and driving the lower track structure, the front work device, and the upper swing structure; a plurality of directional control valves controlling flows of the hydraulic fluid supplied from the hydraulic pump to the respective plurality of hydraulic actuators; an operating room provided in the upper swing structure; left and right operation levers for operating the front work device; and a gate lock lever provided at an entrance of the operating room, and provided such that the gate lock lever can be operated to a getting-on/off permission position at which operation on the plurality of directional control valves is disabled and a getting-on/off prevention position at which the operation on the plurality of directional control valves is enabled, the grip heater apparatus controlling a temperature of a grip section of each of the left and right operation levers. The grip heater apparatus includes: left and right grip heaters provided in the grip portions of the left and right operation levers, respectively; a battery supplying electric power to the left and right grip heaters; a heater switch for instructing the left and right grip heaters to be turned on or off; and a control device supplying the electric power from the battery to the left and right grip heaters only when the engine is running, the gate lock lever is at the getting-on/off prevention position, and the heater switch instructs the left and right grip heaters to be turned on. 
     Advantages of the Invention 
     According to the present invention, it is possible to improve operability by heating the grip portions of left and right operating levers and maintaining a favorable operating environment for the left and right operating levers when work is carried out in a cold region and the operator&#39;s hands get cold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external view of a hydraulic excavator that is equipped with a grip heater apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a perspective view of an operating room of the hydraulic excavator that is equipped with the grip heater apparatus according to the first embodiment of the present invention. 
         FIG. 3  is a perspective view illustrating a lower space of an operator seat of the hydraulic excavator that is equipped with the grip heater apparatus according to the first embodiment of the present invention. 
         FIG. 4  is a configuration diagram of a hydraulic drive system mounted in the hydraulic excavator that is equipped with the grip heater apparatus according to the first embodiment of the present invention. 
         FIG. 5  is a functional block diagram of the grip heater apparatus according to the first embodiment of the present invention. 
         FIG. 6A  is a flowchart illustrating a process by a heater control section of a controller provided in the grip heater apparatus according to the first embodiment of the present invention. 
         FIG. 6B  is a flowchart illustrating a process by the heater control section of the controller provided in the grip heater apparatus according to the first embodiment of the present invention. 
         FIG. 7  is a front view of a display device arranged in an operating room of the hydraulic excavator that is equipped with a grip heater apparatus according to a second embodiment of the present invention. 
         FIG. 8  is a functional block diagram of the grip heater apparatus according to the second embodiment of the present invention. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described hereinafter with reference to the drawings. In the drawings, the same portions are denoted by the same reference characters and repetitive description is omitted as appropriate. 
     [First Embodiment] 
       FIG. 1  is an external view of a hydraulic excavator that is equipped with a grip heater apparatus according to a first embodiment of the present invention. 
     In  FIG. 1 , a hydraulic excavator  1  includes a self-propelled crawler-type lower track structure  2 , an upper swing structure  3  provided in an upper portion of the lower track structure  2  in such a manner as to be swingable, a swing post  4  provided in a front portion of the upper swing structure  3  in such a manner as to be rotationally movable in left and right directions, and a multijoint-type front work device  5  coupled to the swing post  4  in such a manner as to be vertically and rotationally movable (to be capable of being elevated). 
     The lower track structure  2  includes a track frame  6  that is a substantially H-shape in a view from above, left and right driving wheels  7  (only the left side is shown) rotatably supported by vicinities of rear ends of left and right sides of the track frame  6 , left and right driven wheels (idlers)  8  (only the left side is shown) rotatably supported by vicinities of front ends of left and right sides of the track frame  6 , and left and right crawler belts (crawlers)  9  (only the left side is shown) wound around the left and right driving wheels  7  and driven wheels  8 . The left and right driving wheels  7  are driven by left and right travelling hydraulic motors  10  (only the left side is shown), respectively. 
     A blade  11  for earth removal is provided on a front side of the track frame  6  in a vertically movable manner. By driving a blade hydraulic cylinder (not shown) to be expanded/contracted, the blade  11  vertically moves. 
     The upper swing structure  3  includes a swing frame  12  that serves as a base lower structure, a canopy type operating room  13  provided on the swing frame  12 , a counterweight  14  provided in a rear end portion of the swing frame  12 , and an exterior cover  15  covering most of portions on the swing frame  12  except for the operating room  13 . Devices such as an engine and a hydraulic pump driven by the engine are accommodated in an engine room  16  defined by the exterior cover  15  between the operating room  13  and the counterweight  14 . 
     A slewing ring  17  is provided in a central portion of the track frame  6  of the lower track structure  2 , and the swing frame  12  of the upper swing structure  3  is provided swingably via the slewing ring  17 . A swing hydraulic motor (not shown) drives the upper swing structure  3  to swing relatively to the lower track structure  2 . 
     The swing post  4  is provided on a front side of the swing frame  12  of the upper swing structure  3  in such a manner as to be rotationally movable in left and right directions. By driving a swing hydraulic cylinder (not shown) to be expanded/contracted, the swing post  4  rotationally moves in left and right directions and the front work device  5  thereby rotationally moves in left and right directions. 
     The front work device  5  includes a boom  18  coupled to the swing post  4  in such a manner as to be vertically and rotationally movable, an arm  19  coupled to the boom  18  in such a manner as to be vertically and rotationally movable, and a bucket  20  coupled to the arm  19  in such a manner as to be vertically and rotationally movable. By driving a boom hydraulic cylinder  21 , an arm hydraulic cylinder  22 , and a bucket hydraulic cylinder  23  to be expanded/contracted, the boom  18 , the arm  19 , and the bucket  20  vertically and rotationally move. 
     An operator seat (seat)  24  on which an operator is seated is arranged in the operating room  13 . Left and right travelling lever pedals  25  (only the left side is shown) capable of being operated by either hands or feet and instructing a motion of the left and right travelling hydraulic motors  10  (that is, the left and right crawler belts  9 ) by being operated forwardly and backwardly are arranged in front of the operator seat  24 . 
       FIG. 2  is a perspective view of the operating room  13  of the hydraulic excavator  1 . 
     In  FIG. 2 , a crisscross operating type arm/swing operation lever (left operation lever)  26  instructing a motion of the arm hydraulic cylinder  22  (that is, the arm  19 ) by being operated forwardly and backwardly, and instructing a motion of the swing hydraulic motor (that is, the upper swing structure  3 ) by being operated left and right directions is provided on the left side of the operator seat  24 . A gate lock lever  27  capable of being operated to a down position (getting-on/off prevention position) for preventing the operator from getting on or off the hydraulic excavator  1  and to an up position (getting-on/off permission position) for permitting the operator to get on or off the hydraulic excavator  1  is provided in front of the left operation lever  26  (that is, at an entrance of the operating room  13 ). 
     A crisscross operating type boom/bucket operation lever (right operation lever)  28  instructing a motion of the boom hydraulic cylinder  21  (that is, the boom  18 ) by being operated forwardly and backwardly and instructing a motion of the bucket hydraulic cylinder  23  (that is, the bucket  20 ) by being operated left and right directions, and a blade operation lever (not shown) instructing a motion of the blade hydraulic cylinder (that is, the blade  11 ) by being operated forwardly and backwardly are arranged on the right side of the operator seat  24 . A display device  29  displaying various information about the hydraulic excavator  1  in response to operator&#39;s operation is provided in front of the right operation lever  28 . A key switch  30  instructing start/stop of the engine, a dial (not shown) instructing a target revolution speed of the engine, and the like are arranged in rear of the right operation lever  28 . 
     Left and right grip heaters  31  and  32  each having a heater line or a flexible heat transfer substrate are contained in grip portions of the left and right operation levers  26  and  28 , respectively, and a temperature sensor  33  is contained in the grip section of any one of the left and right operation levers  26  and  28  (the right operation lever  28  in the present embodiment). An alternate heater switch  34  for instructing the left and right grip heaters  31  and  32  to be turned ON/OFF is arranged in an operation section of the display device  29 . As shown in  FIG. 3 , the left and right grip heaters  31  and  32  are controlled by a controller  35  arranged in a lower space of the operator seat  24 . A function of the controller  35  will be described later. 
       FIG. 4  is a configuration diagram of a hydraulic drive system mounted in the hydraulic excavator  1 . For the sake of simplification of description,  FIG. 4  illustrates only configurations related to driving of the left travelling hydraulic motor  10  and the boom hydraulic cylinder  21  and does not illustrate configurations related only to driving of the right travelling hydraulic motor, the arm hydraulic cylinder  22 , the bucket hydraulic cylinder  23 , the turning hydraulic motor, the swing hydraulic cylinder, and the blade hydraulic cylinder. 
     In  FIG. 4 , the hydraulic drive system includes an engine  36 , a hydraulic pump  37  and a pilot pump  38  each driven by the engine  36  and delivering a hydraulic fluid, an alternator  39  driven by the engine  36  and generating electric power, a battery  40  charged with electric power by the alternator  39  and supplying the electric power to electric components such as the left and right grip heaters  31  and  32 , a hydraulic pilot type operating device  41  including the left travelling lever pedal  25 , a left travelling directional control valve  42  controlling a flow of the hydraulic fluid from the hydraulic pump  37  to the left travelling hydraulic motor  10  in response to a forward or backward operation on the left travelling lever pedal  25 , a hydraulic pilot type operating device  43  including the boom/bucket operation lever  28 , and a boom directional control valve  44  controlling a flow of the hydraulic fluid from the hydraulic pump  37  to the boom hydraulic cylinder  21  in response to a forward or backward operation on the boom/bucket operation lever  28 . 
     The left travelling directional control valve  42 , the boom directional control valve  44 , and other directional control valves (which specifically include a right travelling directional control valve, an arm directional control valve, a bucket directional control valve, a turning directional control valve, a swing directional control valve, and a blade directional control valve that are not shown) are of center bypass type, and each include a center bypass passage located on a center bypass line  45 . The center bypass passage of each directional control valve, which is connected to the center bypass line  45  in series, opens the center bypass line  45  when a spool of each directional control valve is at a neutral position, and interrupts the center bypass line  45  when the spool is switched to a left or right switching position in  FIG. 4 . An upstream side of the center bypass line  45  is connected to a delivery line  46  of the hydraulic pump  37 , and a downstream side of the center bypass line  45  is connected to a tank line  47 . 
     The left travelling directional control valve  42  is switched by a pilot pressure outputted from the operating device  41 . The operating device  41  includes the left travelling lever pedal  25  and a pair of pilot valves (not shown) each generating a pilot pressure in response to a forward or backward operation on the left travelling lever pedal  25  using a delivery pressure of the pilot pump  38  as an original pressure. When the left travelling lever pedal  25  is operated forward from a neutral position, the pilot pressure generated by one of the pilot valves acts on a pressure receiving section, which is on the right side in  FIG. 4 , of the left travelling directional control valve  42  in response to an operation amount, and the left travelling directional control valve  42  is switched to the switching position on the right side in  FIG. 4 . The left travelling hydraulic motor  10  thereby rotates in a forward direction to drive the left driving wheel  7  and the crawler belt  9  forward. On the other hand, when the left travelling lever pedal  25  is operated backward from the neutral position, the pilot pressure generated by the other pilot valve acts on a pressure receiving section, which is on the left side in  FIG. 4 , of the left travelling directional control valve  42  in response to an operation amount, and the left travelling directional control valve  42  is switched to the switching position on the left side in  FIG. 4 . The left travelling hydraulic motor  10  thereby rotates in a backward direction to drive the left driving wheel  7  and the crawler belt  9  backward. 
     The boom directional control valve  44  is switched by a pilot pressure outputted from the operating device  43 . The operating device  43  includes the boom/bucket operation lever  28  and a pair of pilot valves (not shown) each generating a pilot pressure in response to a forward or backward operation on the operation lever  28  using the delivery pressure of the pilot pump  38  as the original pressure. When the operation lever  28  is operated forward from a neutral position, the pilot pressure generated by one of the pilot valves acts on a pressure receiving section, which is on the right side in  FIG. 4 , of the boom directional control valve  44  in response to an operation amount, and the boom directional control valve  44  is switched to the switching position on the right side in  FIG. 4 . The boom hydraulic cylinder  21  is thereby contracted to move down the boom  18 . On the other hand, when the operation lever  28  is operated backward from the neutral position, the pilot pressure generated by the other pilot valve acts on a pressure receiving section, which is on the left side in  FIG. 4 , of the boom directional control valve  44  in response to an operation amount, and the boom directional control valve  44  is switched to the switching position on the left side in  FIG. 4 . The boom hydraulic cylinder  21  is thereby expanded to move up the boom  18 . 
     A pilot relief valve  49  is provided in a delivery line  48  of the pilot pump  38  for keeping the delivery pressure of the pilot pump  38  constant. A lock valve  50  is also provided in the delivery line  48  of the pilot pump  38  and the lock valve  50  is switched in response to operation on the gate lock lever  27 . Specifically, when the gate lock lever  27  is operated to the down position, a lock switch  51  is closed to carry a current to a solenoid drive section of the lock valve  50 , and the lock valve  50  is switched to a communication position which is on the lower side in  FIG. 4 . The original pressure is thereby supplied from the pilot pump  38  to the operating devices  41 ,  43 , and the like, and the operating devices  41 ,  43 , and the like are capable of operating the directional control valves  42 ,  44 , and the like. On the other hand, when the gate lock lever  27  is operated to the up position, the lock switch  51  is opened to stop carrying the current to the solenoid drive section of the lock valve  50 , and the lock valve  50  is switched to a neutral position, which is on the upper side in  FIG. 4 , by a force of a spring. Supply of the original pressure from the pilot pump  38  to the operating devices  41 ,  43 , and the like is thereby interrupted, and the operating devices  41 ,  43 , and the like are incapable of operating the directional control valves  42 ,  44 , and the like. 
       FIG. 5  is a functional block diagram of the grip heater apparatus. 
     In  FIG. 5 , a grip heater apparatus  100  includes the controller  35 , the alternator  39 , the lock switch  51 , the temperature sensor  33 , the heater switch  34 , and the left and right grip heaters  31  and  32 . 
     The controller  35  includes a heater control section  35   a  that controls the left and right grip heaters  31  and  32  on the basis of input signals from the alternator  39 , the lock switch  51 , the temperature sensor  33 , and the heater switch  34  and a predetermined set temperature. 
       FIGS. 6A and 6B  are flowcharts illustrating processes by the heater control section  35   a . A flow shown in  FIG. 6A  is a flow for monitoring ON/OFF states of the heater switch  34 , while a flow shown in  FIG. 6B  is a flow for controlling the grip heaters  31  and  32 . The heater control section  35   a  executes the two flows shown in  FIGS. 6A and 6B  in parallel. The flows will be described below in sequence. 
     In the flow of  FIG. 6A , the heater control section  35   a  first judges whether the heater switch  34  on the display device  29  has been depressed (Step S 110 ). 
     When it is judged in Step S 110  that the heater switch  34  has not been depressed (NO), the heater control section  35   a  returns to Step S 110 . 
     On the other hand, when determining in Step S 110  that the heater switch  34  has been depressed (YES), the heater control section  35   a  determines whether a switch state flag is OFF (Step S 120 ). It is noted here that the switch state flag is a flag that indicates which state, ON or OFF, the alternate heater switch  34  is in and is stored in a memory (not shown) of the controller  35 . 
     When it is judged in Step S 120  that the switch state flag is OFF (YES), the heater control section  35   a  sets the switch state flag to ON (Step S 130 ), and returns to Step S 110 . 
     On the other hand, when it is judged in Step S 120  that the switch state flag is ON (NO), the heater control section  35   a  sets the switch state flag to OFF (Step S 140 ), and returns to Step S 110 . 
     In the flow of  FIG. 6B , the heater control section  35   a  first judges whether the engine  36  is running on the basis of the signal from the alternator  39  (Step S 210 ). 
     When it is judged in Step S 210  that the engine  36  is running (YES), the heater control section  35   a  judges whether the gate lock lever  27  is at the down position on the basis of the signal from the lock switch  51  (Step S 220 ). 
     When it is judged in Step S 220  that the gate lock lever  27  is at the down position (YES), the heater control section  35   a  determines whether the switch state flag is ON (Step S 230 ). 
     When it is judged in Step S 230  that the switch state flag is ON (YES), the heater control section  35   a  turns on the left and right grip heaters  31  and  32  and adjusts the electric power supplied to the left and right grip heaters  31  and  32  in such a manner as to reduce a difference between a temperature of the grip section of the right operation lever  28  detected by the temperature sensor  33  and the predetermined set temperature (Step S 240 ), and returns to Step S 210 . 
     On the other hand, when it is judged NO in any one of Steps S 210 , S 220  and S 230 , the heater control section  35   a  turns off the left and right grip heaters  31  and  32  (Step S 250 ), and returns to Step S 210 . 
     The grip heater apparatus  100  according to the present embodiment configured as described above improve operability by heating the grip portions of left and right operating levers  26  and  28  and maintaining a favorable operating environment for the left and right operating levers  26  and  28  when work is carried out in a cold region and the operator&#39;s hands get cold. 
     Furthermore, when the engine  36  is stopped or when the gate lock lever  27  is at the getting-on/off permission position (that is, when the operation on the left and right operation levers  26  and  28  is disabled), the supply of the electric power from the battery  40  to the left and right grip heaters  31  and  32  is stopped whether the heater switch  34  is turned on or off. It is thereby possible to prevent unnecessary power consumption due to, for example, an omission to turn off the heater switch  34  when the operator temporarily gets off the hydraulic excavator  1 . 
     [Second Embodiment] 
     A grip heater apparatus according to a second embodiment of the present invention will be described while centering on differences from the first embodiment. The grip heater apparatus according to the present embodiment is configured such that a temperature adjustment function for the left and right grip heaters  31  and  32  is added to the grip heater apparatus  100  (refer to  FIG. 5 ) according to the first embodiment. 
       FIG. 7  is a front view of the display device  29  provided at the operator seat  24  of the hydraulic excavator  1 . 
     In  FIG. 7 , not only the heater switch  34  but also an alternate temperature increase switch  52  for instructing the temperatures of the left and right grip heaters  31  and  32  to be increased and an alternate temperature decrease switch  53  for instructing the temperatures of the left and right grip heaters  31  and  32  to be decreased are provided in an operation section  29   a  of the display device  29 . Furthermore, a set temperature indicator  54  for displaying a set temperature of the left and right grip heaters  31  and  32  is provided in a display section  29   b  of the display device  29 . 
       FIG. 8  is a functional block diagram of the grip heater apparatus according to the present embodiment. 
     In  FIG. 8 , a grip heater apparatus  100 A includes a controller  35 A as an alternative to the controller  35  (refer to  FIG. 5 ) according to the first embodiment, and further includes the temperature increase switch  52 , the temperature decrease switch  53 , and the set temperature indicator  54 . 
     In  FIG. 8 , the controller  35 A includes a heater temperature setting section  35   b  in addition to the heater control section  35   a  (refer to  FIG. 5 ) according to the first embodiment. 
     When the temperature increase switch  52  is depressed, the heater temperature setting section  35   b  increases the set temperature of the left and right grip heaters  31  and  32  stepwise, and lengthens the lit-up portion of the set temperature indicator  54  of the display section  29   b  stepwise. When the temperature increase switch  52  is depressed, the heater temperature setting section  35   b  decreases the set temperature of the left and right grip heaters  31  and  32  stepwise, and shortens the lit-up portion of the set temperature indicator  54  of the display section  29   b  stepwise. 
     The grip heater apparatus  100 A according to the present embodiment configured as described above can attain similar effects to those of the first embodiment. Furthermore, by providing the temperature increase switch  52 , the temperature decrease switch  53 , and the set temperature indicator  54 , it is possible to adjust the temperatures of the left and right grip heaters  31  and  32  depending on an operating condition of the left and right operation levers  26  and  28  (such as whether the left and right operation levers  26  and  28  are operated with bare hands or with work gloved hands) and an operating environment (such as an outside air temperature). 
     While the grip heater apparatus  100  or  100 A according to the embodiments described above is applied to the hydraulic excavator  1  equipped with the canopy type operating room  13 , the present invention is not limited to this application and is also applicable to a hydraulic excavator equipped with a cab type operating room. In that case, the grip heater apparatus  100  or  100 A can improve operability by heating the grip portions of left and right operating levers  26  and  28  with the left and right grip heaters  31  and  32  turned on and maintaining a favorable operating environment for the left and right operating levers when work is carried out in a cold region with the cab door left open in order to secure, for example, a wide field of vision of surroundings of a machine body. 
     Moreover, the present invention is not limited to the embodiments described above and encompasses various modifications. For example, although the abovementioned embodiments have been described in detail for describing the present invention so that the present invention is easy to understand, the present invention is not necessarily limited to the embodiments having all the configurations described above. Moreover, the configuration of an embodiment can be partially replaced by the configuration of another embodiment or the configuration of an embodiment can be added to the configuration of another embodiment. Furthermore, for a part of the configuration of each embodiment, addition, deletion, or replacement of the other configuration can be made. 
     DESCRIPTION OF REFERENCE CHARACTERS 
     
         
           1 : Hydraulic excavator (construction machine) 
           2 : Lower track structure 
           3 : Upper swing structure 
           4 : Swing post 
           5 : Front work device 
           6 : Track frame 
           7 : Driving wheel 
           8 : Driven wheel 
           9 : Crawler belt 
           10 : Left travelling hydraulic motor (hydraulic actuator) 
           11 : Blade 
           12 : Swing frame 
           13 : Operating room 
           14 : Counterweight 
           15 : Exterior cover 
           16 : Engine room 
           17 : Slewing ring 
           18 : Boom 
           19 : Arm 
           20 : Bucket 
           21 : Boom hydraulic cylinder (hydraulic actuator) 
           22 : Arm hydraulic cylinder (hydraulic actuator) 
           23 : Bucket hydraulic cylinder (hydraulic actuator) 
           24 : Operator seat 
           25 : Left travelling lever pedal 
           26 : Arm/swing operation lever (left operation lever) 
           27 : Gate lock lever 
           28 : Boom/bucket operation lever (right operation lever) 
           29 : Display device 
           29   a : Operation section 
           29   b : Display section 
           30 : Key switch 
           31 : Left grip heater 
           32 : Right grip heater 
           33 : Temperature sensor 
           34 : Heater switch 
           35 ,  35 A: Controller (control device) 
           35   a : Heater control section 
           35   b : Heater temperature setting section 
           36 : Engine 
           37 : Hydraulic pump 
           38 : Pilot pump 
           39 : Alternator 
           40 : Battery 
           41 : Operating device 
           42 : Left travelling directional control valve 
           43 : Operating device 
           44 : Boom directional control valve 
           45 : Center bypass line 
           46 : Hydraulic pump delivery line 
           47 : Tank line 
           48 : Pilot pump delivery line 
           49 : Pilot relief valve 
           50 : Lock valve 
           51 : Lock switch 
           52 : Temperature increase switch 
           53 : Temperature decrease switch 
           54 : Set temperature indicator 
           100 ,  100 A: Grip heater apparatus