JP2009228297A - Work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance safety by a simple configuration without occupying the floor part of a cabin having a front door. <P>SOLUTION: This work vehicle includes a working device operated by hydraulic cylinders 6, 7, a door switch 53D installed on a front door openably formed at an entrance opening at the front of the cabin, pilot hydraulic control valves 31-33 for operating a main pump 14 and the cylinders 6, 7 which are installed in a hydraulic oil supply line 35 for connecting the main pump 14 to the cylinders 6, 7, and a traveling-handling interlock controller 54 which connects a pilot supply line 34 for supplying a pilot pressure oil to pilot valves 31P-33P for operating the control valves 31-33 by the pilot pressure oil, which has a load handling lock valve 52 in the pilot supply line 34, and which outputs a load handling lock signal to the load handling lock valve 52 according to a front door 11 opening detection signal by the door switch 53D. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a work vehicle having a work device driven by a hydraulic work drive device, and a front door that is provided in a freely openable / closable opening at a front surface of a cabin.

  A small work vehicle such as a conventional skid steer loader has a cockpit surrounded by a cabin installed in the center of the vehicle body, and a pair of left and right work booms extending forward from both sides of the rear of the vehicle with the cabin in between. It is rotatably supported by. And the bucket is supported by the front end part of the left and right work booms so as to be rotatable in the vertical direction. And the boarding / alighting opening part is formed in the cabin front surface, and it gets on and off to the cockpit in a cabin across a bucket.

  By the way, in the work vehicle used in a warm climate, since the cabin only needs to block direct sunlight and ensure air permeability, the entrance / exit opening is opened. However, in a work vehicle used in a cold climate, a front door is provided at the entrance / exit opening so as to be openable and closable in order to block the cabin from outside air.

By the way, when the front boom is opened and the work boom is raised and lowered or the bucket is rotated, the front door may be damaged or the operator may be exposed to danger.
For this reason, in Patent Document 1, when it is detected that the front door is open, a safety device is provided that prevents the cargo handling pedal from being locked and depressed by raising the lock bar by a solenoid and engaging and fixing the lock bar to the bottom of the cargo handling pedal. Additional work vehicles have been proposed.
Japanese Utility Model Publication 4-31328

  However, in the above configuration, mechanical parts such as shafts, lock bars, and levers must be disposed in the space below the cargo handling pedal on the cockpit floor, and sufficient space for the safety device is provided on the narrow cabin floor. There is a problem that it is necessary and the inside of the cabin tends to be narrow.

  An object of the present invention is to solve the above problems and provide a work vehicle that can improve safety with a simple configuration in a work vehicle equipped with a cabin having a front door.

  According to the first aspect of the present invention, there is provided a work vehicle having a front door having a front door that can be freely opened and closed at a passenger opening formed on a front surface of a cabin surrounding a cockpit, and is driven by a hydraulic work drive device. And a door opening / closing detector for detecting opening / closing of the front door, and operating the work driving device on the hydraulic oil supply line connected between the hydraulic pump driven by the engine and the work driving device. A pilot hydraulic work operation valve is provided, an operation pilot valve for supplying and discharging pilot pressure oil to the pilot portion of the operation operation valve is provided, and a cargo handling lock is provided on a pilot supply pressure line for supplying pilot pressure oil to the operation pilot valve. A valve is provided and a cargo handling lock signal for stopping the supply of pilot pressure oil is handled based on the door opening detection signal from the door opening / closing detector. It is provided with a interlocking controller to be output to Kkubarubu.

  According to a second aspect of the present invention, in the configuration according to the first aspect, a seat bar for detecting the seating of an operator is provided in the seat of the cockpit, and the seat bar is provided at the front portion of the cockpit so as to be able to be opened and closed freely. And a bar opening / closing detector for detecting opening / closing of the seat bar, and the interlock controller outputs a door opening detection signal, a separation detection signal output from the seating detector, and the bar opening / closing detector. When any one of the bar opening detection signals is input, the cargo handling lock signal is output to the cargo handling lock valve.

  According to a third aspect of the present invention, in the configuration according to the second aspect, a brake valve that operates by supplying and discharging hydraulic oil to and from a brake cylinder of the traveling brake device is provided to control a traveling motor that rotationally drives the traveling wheels. An operation valve and a travel lock valve interposed in a travel supply pressure line for supplying operating pressure oil to the travel operation valve are provided, and the interlock controller brakes the travel wheels to the brake valve simultaneously with the cargo handling lock signal. A lock signal and a travel lock signal for stopping the supply of pilot pressure oil to the travel operation valve are output to the travel lock valve.

  According to the first aspect of the present invention, when the front door is opened, the door opening / closing detector detects and outputs a door opening detection signal to the interlock controller. The interlock controller outputs a cargo handling lock signal to the cargo handling lock valve, stops the supply of pilot pressure oil to the work operation valve, locks the work operation valve, and thereby stops the work drive device. Therefore, the work device is not operated in a state where the front door is opened, the door can be prevented from being damaged by the work device, and the safety of the operator can be improved. Further, since it is constituted by a valve or a detector provided in the hydraulic piping, the floor portion of the cabin is not greatly occupied with a simple configuration.

  According to the configuration of claim 2, in addition to the door opening detection signal output from the door opening / closing detector when the front door is opened, the seating detection signal output from the seating detector when the operator leaves the seat. When the seat bar is opened, the bar opening / closing detection signal output from the bar open / close detector outputs a cargo handling lock signal from the interlock controller to the cargo handling lock valve, which locks the work operation valve and drives the work. Since the apparatus is stopped, safety can be further improved.

  According to the configuration of the third aspect, when any one of the door opening detection signal, the separation detection signal, and the bar opening detection signal is output, the driving motor is locked and the traveling motor is stopped and the traveling brake device is operated. Since the vehicle body is braked, safety can be further improved.

Embodiments of a work vehicle according to the present invention will be described below with reference to the drawings.
[Embodiment]
As shown in FIG. 3, a skid steer loader that is a small work vehicle includes a body 1 having a pair of left and right front wheels (traveling wheels) 2F and a pair of left and right rear wheels (traveling wheels) 2R. A working device 4 is provided. The work device 4 includes a pair of left and right work booms 5 that are supported on the both sides of the rear part of the vehicle body 1 so as to be pivotable in the vertical direction and extend forward, and the front end parts of the work booms 5 are rotated in the vertical direction. A boom 3 (work drive device) 6 that includes a bucket 3 that is movably supported and is connected between the rear portion of the vehicle body 1 and the front end side of the work boom 5 is rotated in the vertical direction. The bucket 3 is rotated in the vertical direction by a bucket cylinder (work drive device) 7 connected between the front end side of the work boom 5 and the back surface of the bucket 3.

  A pilot seat 8 disposed between the left and right work booms 5 at the center of the vehicle body 1 is provided with a cabin 9 surrounded by left and right side plates, a back plate, and a ceiling plate. A getting-on / off opening 9a is formed so that the operator can get on and off the bucket 3 and get on and off. A single-open front door 11 is provided at the entrance / exit opening 9a through a hinge 11a so as to be freely opened and closed. In addition, on the left and right sides of the front of the seat 12 installed in the cockpit 8, an overlaid seat bar 13R that prevents the operator from jumping out of the seat 12 in a horizontal posture and opens the seat 12 in a standing posture. , 13L are provided so as to freely open and close.

  As shown in FIG. 2, a hydraulic main pump (hydraulic pump) 14, a sub pump (hydraulic pump) 15, and left and right traveling pumps 21 </ b> R and 21 </ b> L that are rotationally driven by an engine 10 are mounted on the vehicle body 1. A work controller 30 for operating the device 4, a traveling device 20 for driving the left and right front and rear wheels 2F, 2R, a traveling brake device 40, and a safety device 50 according to the present invention are provided.

  In the traveling device 20, a hydraulic left traveling motor 23L is connected to the left traveling pump 21L via a left closed loop line 22L, and the left front and rear wheels 2F and 2R are connected to the left traveling motor 23L via a speed reducer. Are each driven to rotate. Also, a hydraulic right traveling motor 23R is connected to the right traveling pump 21R via a right closed loop line 22R, and the right front and rear wheels 2F and 2R are coupled to the right traveling motor 23R via a speed reducer, and are driven to rotate. Is done. The left and right traveling pumps 21R and 21L are variable displacement axial piston pumps having control operation cylinders 21a and 21b capable of operating the discharge amount and the discharge direction, and the left and right traveling motors 23R and 23L are constant displacement orbits. It is a motor (torque motor).

  A traveling operation pressure supply line 25 for supplying and discharging operating pressure oil is connected between the left and right closed loop lines 22R and 22L and the control operation cylinders 21a and 21b of the left and right traveling pumps 21R and 21L. Left and right traveling operation valves 24R and 24L are interposed in the branch line of the line 25, respectively. The left and right travel operation valves 24R, 24L are configured to be operated by a left / right steering lever (not shown) or a joystick lever disposed only on the left side. Thereby, the operation pressure oil supplied to the traveling operation valves 24R and 24L from the traveling operation supply pressure line 25 is controlled by the left and right traveling operation valves 24R and 24L, respectively, and is supplied to and discharged from the control operation cylinders 21a and 21b. The rotational speed and direction of the left and right traveling motors 23R, 23L are controlled.

A solenoid type travel lock valve 51 constituting the safety device 50 is interposed in the travel operation supply pressure line 25.
The traveling brake device 40 that brakes the vehicle body 1 includes a solenoid and a pedal-operating brake valve 41, and braking cylinders 42R and 42L that brake the output shafts of the left and right traveling motors 23R and 23L by brake members, respectively. The hydraulic oil discharged from the sub pump 15 is sent from the sub hydraulic oil supply line 43 to the brake valve 42, and is further sent from the brake valve 42 to the brake cylinders 42R and 42L to operate the travel brake device 40, and the travel motor 23R. , 23L are braked respectively.

  The work controller 30 is interposed in a hydraulic oil supply line 35 that feeds hydraulic oil from the main pump 14 to the boom cylinder 6 and the bucket cylinder 7 and a separately attached work attachment (not shown). A pilot hydraulic boom control valve (work operation valve) 31, a pilot hydraulic bucket control valve (work operation valve) 32 for operating the bucket cylinder 7, and a pilot hydraulic ATT control valve for operating the work attachment ( A boom pilot valve 31P for operating the boom control valve 31, a bucket pilot valve 32P for operating the bucket control valve 32, and an ATT control valve 33. ATT pilot valve 33P are respectively provided, each of these pilot valve @ 31 P, @ 32 P, 33P is configured to operated by for example the operation pedal or the operation lever. Pilot pressure oil for driving the pilot valves 31P, 32P, 33P is supplied through a pilot supply pressure line 34 branched from the sub hydraulic oil supply line 43, respectively. Further, a solenoid-type cargo handling lock valve 52 capable of stopping the supply of pilot pressure oil is interposed in the pilot supply pressure line 34. Reference numeral 36 denotes a hydraulic pressure discharge line for discharging pilot pressure oil from the pilot valves 31P, 32P, 33P and surplus hydraulic oil from the control valves 31, 32, 33.

  The safety device 50 is installed in the vicinity of the hinge 11a at the lower part of the front door 11 and is installed in a door switch (door open / close detector) 53D for detecting the open / closed state of the front door 11 and in the seat 12 to be seated / separated by the operator. A safety detection unit 53 comprising three types of detectors: a seat switch (sitting detector) 53S for detecting a seat and left and right seat bar switches (bar opening / closing detectors) 53B for detecting the up-and-down opening / closing state of the seat bars 13R and 13L. And a travel / load handling interlock controller (interlock controller) 54 operated based on each detection signal from the safety detection unit 53, and a travel lock solenoid 51 s operated by the travel / load handling interlock controller 54. A cargo handling lock having a lock valve 51 and a cargo handling lock solenoid 52s. It is composed of a valve 52 and brake valve 41 having a brake lock solenoid 41s.

  In this safety device 50, 1) When the front door 11 is opened, a door open detection signal is output from the door switch 53D that detects this to the traveling / loading interlock controller 54, and 2) the operator leaves the seat 12 Then, a seat separation detection signal is output from the seat switch 53S that detects this to the traveling / loading interlock controller 54, and 3) when the seat bars 13R and 13L are raised and opened, the seat bar switch 53B that detects this is detected. The bar opening detection signal is output to the traveling / loading interlock controller 54 from the vehicle. When one of the detection signals 1) to 3) is input to the traveling / loading interlock controller 54, the loading / unloading lock signal is output to the loading / unloading solenoid 52s of the loading / unloading lock valve 52 to lock the traveling lock. A signal is output to the travel lock solenoid 51s of the travel lock valve 51, and a brake lock signal is output to the brake lock solenoid 41s of the brake valve 41.

  When the cargo handling lock signal is output to the cargo handling lock solenoid 52s, the cargo handling lock valve 52 is switched to the closed position, and the pilot pressure oil is supplied from the pilot supply pressure line 34 to the pilot valves 31P, 32P, 31P of the work controller 30. Is stopped. Thereby, since each control valve 31,32,33 is each locked, even if an operation pedal or an operation lever is operated, the working device 4 is not actuated.

  When the travel lock signal is output to the travel lock solenoid 51s, the travel lock valve 51 is switched to the closed position, and the supply of operation pressure oil sent from the travel operation pressure supply line 25 to the travel operation valves 24R and 24L is stopped. Is done. Thus, the travel operation valves 24R and 24L are locked, and the travel pumps 21R and 21L are not driven even when the steering lever is operated.

  Further, when a brake lock signal is output to the brake lock solenoid 41s, the brake valve 41 is turned on and held, hydraulic oil is supplied to the brake cylinders 42R and 42L, and the output shafts of the travel motors 23R and 23L are braked, respectively. And locked. Thereby, even if the brake pedal is released, the braking state is continued and the vehicle body 1 is stopped.

  According to the above embodiment, when opening of the front door 11 is detected by the door switch 53D and a door opening detection signal is output to the traveling / loading interlock controller 54, the traveling / loading interlock controller 54 loads the cargo handling lock valve. Since the cargo handling lock signal is output to 52, even if the operation pedal or the operation lever is operated, the pilot pressure oil is not sent from the pilot valves 31P, 32P, 33P to the control valves 31, 32, 33. The valves 31, 32 and 33 are locked, and the boom cylinder 6, the bucket cylinder 7 and the work attachment are driven and stopped. Thereby, the work boom 5 and the bucket 3 are not operated in a state where the front door 11 is opened, and safety can be improved. Moreover, since the structural members of these safety devices are composed of a plurality of detectors and valves, they can be configured easily and do not occupy the floor surface of the cabin 9.

  In addition, in the traveling / loading interlock controller 54, in addition to the door opening detection signal output from the door switch 53D, any of the separation detection signal output from the seat switch 53S and the bar opening detection signal output from the seat bar switch 53B is used. Even when one of them is output, the cargo handling lock signal is sent to the cargo handling lock valve 52 and locked, and the work device 4 is stopped, so that safety can be further improved.

  Further, in the traveling / loading interlock controller 54, any one of the door opening detection signal output from the door switch 53D, the separation detection signal output from the seat switch 53S, and the bar opening detection signal output from the seat bar switch 53B. When one of these is output, a cargo handling lock signal, a traveling lock signal, and a brake lock signal are output, respectively, and the traveling lock valve 51 and the brake valve 41 are locked together with the cargo handling lock valve 52, and the work device 4 is stopped. Since the stop of the traveling steering and the braking of the vehicle body 1 are performed at the same time, the safety can be further improved.

It is a schematic perspective view which shows embodiment of the skid steer loader which concerns on this invention, and shows arrangement | positioning in a cabin. It is a block diagram which shows the structure of a skid steer loader. It is a front perspective view which shows a skid steer loader.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2F Front wheel 2R Rear wheel 3 Bucket 4 Work device 5 Work boom 6 Boom cylinder (work drive device)
7 Bucket cylinder (work drive unit)
8 Control seat 9 Cabin 9a Entrance door 11 Front door 12 Seat seat 13R, 13L Seat bar 20 Travel device 21R, 21L Travel pump 21a, 21b Control operation cylinder 22R, 22L Closed loop line 23R, 23L Travel motor 24R, 24L Travel operation valve 30 Work controller 31 Boom control valve (work operation valve)
31P Boom pilot valve (operating pilot valve)
32 Bucket control valve (work operation valve)
32P bucket pilot valve (operating pilot valve)
33 ATT control valve (work operation valve)
33P ATT pilot valve (operating pilot valve)
34 Pilot supply pressure line 35 Hydraulic oil supply line 40 Travel brake device 41 Brake valve 41s Brake lock solenoids 42R, 42L Brake cylinder 43 Sub hydraulic oil supply line 50 Safety device 51 Travel lock valve 51s Travel lock solenoid 52 Cargo lock valve 52s Cargo lock Solenoid 53 Safety detector 53D Door switch (door open / close detector)
53S Seat switch (sitting detector)
53B Seat bar switch (Bar open / close detector)
54 Travel and cargo handling interlock controller (interlock controller)

Claims (3)

A work vehicle having a front door that can be opened and closed at a passenger opening formed on the front surface of a cabin surrounding a cockpit,
A work device driven by a hydraulic work drive device is provided,
A door open / close detector is installed to detect the opening and closing of the front door.
Provided with a hydraulic hydraulic supply line connected between the hydraulic pump driven by the engine and the work drive device, a pilot hydraulic work operation valve for operating the work drive device,
An operation pilot valve for supplying and discharging pilot pressure oil to the pilot portion of the work operation valve is provided,
A cargo handling lock valve is provided in a pilot supply pressure line for supplying pilot pressure oil to the operation pilot valve,
A work vehicle comprising: an interlock controller that outputs a cargo handling lock signal for stopping the supply of pilot pressure oil to a cargo handling lock valve based on a door opening detection signal from the door opening / closing detector. A seat detector for detecting the operator's seating is provided on the cockpit seat,
A seat bar provided in the front part of the cockpit to be freely opened and closed, and a bar opening / closing detector for detecting opening and closing of the seat bar are provided.
The interlock controller receives a door opening detection signal, a separation detection signal output from the seating detector, and a bar opening detection signal output from the bar opening / closing detector. The work vehicle according to claim 1, wherein the work vehicle is configured to output a signal to a cargo handling lock valve. A brake valve that operates by supplying and discharging hydraulic oil to the braking cylinder of the traveling brake device is provided.
A travel operation valve that controls a travel motor that rotationally drives the travel wheels, and a travel lock valve that is interposed in a travel supply pressure line that supplies operation pressure oil to the travel operation valve,
The interlock controller simultaneously outputs a brake lock signal for braking the traveling wheel to the brake valve and a travel lock signal for stopping the supply of pilot pressure oil to the travel operation valve to the travel lock valve simultaneously with the cargo handling lock signal. It is comprised so that it may output. The work vehicle of Claim 2 characterized by the above-mentioned.

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