JP2001294139A - Hand guide roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hand guide roller of high safety capable of surely preventing sudden descending from being initiated even when an engine is suddenly stalled in compaction work or the like in a slope face. SOLUTION: A detection means for detecting an engine-stalled condition of an engine E, and a stopping means 42 for stopping a supply of hydraulic fluid to a negative brake mechanism 23 when the stalled condition of the engine E is detected by the detection means are provided in this guide roller provided with a clutch mechanism 10 connected when an engine speed reaches to a prescribed speed, a closed circuit 14 formed of a hydraulic pump P driven by the engine E via the clutch mechanism 10 and formed of travel hydraulic motors M1, M2 for driving travel rolls (a front roll 2 and a rear roll 3), a charge pump Pc rotated with the rotation of the hydraulic pump P to replenish the hydraulic fluid to the closed circuit 14, and the negative brake mechanism 23 for conducting braking operation when the supply of the hydraulic fluid from the charge pump Pc is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hand guide roller used for compaction of asphalt pavement or the like.

[0002]

2. Description of the Related Art A hand guide roller is a relatively compact and lightweight non-boarding type vehicle among compaction vehicles that compact a road surface with running rolls, such as an initial rolling pressure of asphalt pavement, a road shoulder, a sidewalk, a narrow alley, and the like. Because of its excellent workability in compaction, it is widely used for municipal road maintenance and environmental improvement. At the rear of the traveling body, an operation rod with an operation panel at the tip is extended, and the operator moves the forward / reverse lever provided on the operation panel from the "neutral" position in the upright position to the front side. The aircraft is moved forward and backward by tilting to the "forward position" by tilting to the "forward position" and tilting to the "reverse position" by tilting to the rear side.

FIG. 7 shows a conventional example of a hydraulic circuit relating to a traveling system of a hand guide roller. Reference numeral C denotes a clutch mechanism such as a centrifugal clutch that is connected when the engine speed reaches a predetermined speed. The hydraulic pump P is, for example, a swash plate type variable displacement piston pump, and is driven by an engine E via a clutch mechanism C and driven by traveling hydraulic motors M5 and M6 which respectively drive traveling rolls (front roll 71 and rear roll 72). A hydraulic closed circuit 81 is configured. The hydraulic pump P switches the angle of the internal swash plate in response to the tilting operation of the forward / backward movement lever to the “forward position” or the “reverse position”, whereby the amount of pressure oil in the closed circuit 81 and The flow is switched between forward and reverse. Therefore, the hand guide rollers move forward or backward as the traveling hydraulic motors M5 and M6 rotate forward and backward with the flow of the pressure oil in the forward and reverse directions. When the forward / reverse lever is set to the “neutral” position, the swash plate position of the hydraulic pump P also becomes neutral, and the hydraulic pump P not only does not circulate the oil in the oil passage but also actively shuts off the oil. The hand guide roller stops running.

The reason why the clutch mechanism C is interposed between the engine E and the hydraulic pump P is that the hand guide roller has a manual cranking mechanism for starting the engine. To prevent the engine E at the time of stop from receiving the starting load from the power transmission device such as the hydraulic motor P and to allow the operator to easily turn the cranking handle with a small force. is there. As described above, the hand guide roller is compact and lightweight as a compacting vehicle, so the mounted engine is also small, so that the engine can be started by manual cranking. According to the configuration provided, not only the economical advantage that the cell motor can be omitted, but also the case where the cell motor stops operating in cold weather is effective.

The closed circuit 81 functions as a transmission for continuously changing the traveling hydraulic motors M5 and M6 by controlling the flow rate in the circuit.
Generally, hydrostatic transmissions (HS
T), and when there is no pressure oil flow due to the closed circuit, a braking force (generally called an HST brake) based on the hydraulic load is generated regardless of the driving state or the stopped state of the engine E. Let it. Sign P
c rotates with the rotation of the hydraulic pump P to rotate the oil tank 73.
Shows a charge pump for replenishing the closed circuit 81 with pressure oil through the check valve 74 or 75, and replenishes the low pressure side of the closed circuit 81 with an insufficient flow rate of the pressure oil. Symbols 76 and 7
Reference numeral 7 denotes a negative brake mechanism that performs a braking operation when the supply of pressure oil from the charge pump Pc stops.
The brake is released when pressure oil is supplied, such as during steady engine rotation. Thus, for example, when the engine E is stopped, the rotation of the hydraulic pump P stops, that is, the flow of the pressure oil in the closed circuit 81 stops, the HST brake acts on the traveling roll, and the rotation of the charge pump Pc. Negative brake mechanism 7 that supply of pressure oil was cut off because it stopped
6,77 brakes will also operate.

[0006]

However, the hand guide roller having the hydraulic circuit described above has the following problems. For example, during compaction work on a slope such as a slope (when the forward / reverse lever is at the “forward position” or the “reverse position”), the engine E stops for some reason such as running out of fuel. Assuming the case, the hand guide roller tries to drop on the slope by its own weight, that is, the traveling roll rotates and the traveling hydraulic motor M
5 and M6 try to rotate, and this traveling hydraulic motor M5
The rotation of M6 performs a pumping action to generate a flow of pressure oil in the closed circuit 81 to rotate the hydraulic pump P. However, since the hydraulic pump P is connected to the engine E, the engine E becomes a load and so-called engine braking is effective, so that the hand guide roller should not suddenly go down the slope.

However, as described above, the engine E
A clutch mechanism C is connected between the hydraulic pump P and the hydraulic pump P when the engine speed reaches a predetermined speed. By C, the engine E and the hydraulic pump P are disconnected. Therefore, in this case, since the load on the engine E and the engine brake are not applied, the flow of the pressure oil easily rotates the hydraulic pump P. At this time, the charge pump Pc
Also rotates at the same time, and the negative brake mechanism 7
6, 77 is supplied with pressure oil, and the brake is released. Therefore, in such a case, the flow rate of the pressure oil in the closed circuit 81 increases due to the rotation of the hydraulic pump P, and the hand guide rollers with the increased rotation of the traveling hydraulic motors M5 and M6 suddenly cut the slope without applying any brake. There was a risk of starting to descend.

If the forward / reverse lever is returned to the "neutral" position at this time, the oil passage in the hydraulic pump P is cut off, so that the flow of the pressure oil in the closed circuit 81 stops and the HST brake operates. At the same time, the rotation of the charge pump Pc is stopped, so that the negative brake mechanisms 76 and 77 operate to apply the brake. However, in the hand guide roller that has begun to descend suddenly, it may be impossible to operate the lever to rotate from the inclined "forward position" or "reverse position" to the "neutral" position in the upright state. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and even if the engine suddenly stops at the time of compaction work on a slope, etc., the present invention is intended to suddenly start descending. It is an object of the present invention to provide a more secure hand guide roller in which the hand guide roller is reliably prevented.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a clutch mechanism connected when an engine speed reaches a predetermined speed, and an engine driven by the engine via the clutch mechanism. A closed circuit formed by a hydraulic pump to be driven and a traveling hydraulic motor that drives a traveling roll; a charge pump that rotates with the rotation of the hydraulic pump to supply pressure oil to the closed circuit; A negative brake mechanism that performs a braking operation when the supply of pressurized oil is stopped,
Detecting means capable of detecting a stopped state of the engine, and stopping means for stopping supply of pressure oil to the negative brake mechanism when the detecting means detects the stopped state of the engine.

Further, the detecting means comprises an engine oil pressure sensor for detecting an engine oil pressure.

Further, when the engine switch for starting the engine is turned off, the supply of the pressure oil to the negative brake mechanism is stopped.

Further, a brake switch is provided for stopping the supply of pressure oil to the negative brake mechanism regardless of whether the engine is driven or stopped.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 (a)
FIG. 1B is a plan view of the hand guide roller, FIG. 1B is a side view of the same, FIG. 2 is a hydraulic circuit diagram relating to the traveling system, FIG. 3 is a sequence control circuit diagram showing detecting means and stopping means, and FIG. FIG. 5 is a side sectional explanatory view showing a brake mechanism, FIG. 5 is a side sectional explanatory view showing a brake release state of a negative brake mechanism, and FIG. 6 is a structural sectional view of a main part when the traveling hydraulic motor is viewed from the front.

In FIG. 1, a hand guide roller H is attached to a body 1 by an engine E serving as a drive source for traveling and the engine E
A hydraulic pump P (omitted in FIG. 1) driven by the motor is mounted. The hydraulic pump P is, for example, a swash plate type variable displacement piston pump. A pair of front and rear traveling rolls (a front roll 2 and a rear roll 3) are provided at a lower portion of the body 1, and traveling hydraulic motors M1 and M2, each of which operates by receiving supply of pressure oil from a hydraulic pump P, are provided inside. ing. The negative brake mechanism described in detail later includes only the traveling hydraulic motor M2 on the rear roll 3 side. An operation rod 5 is extended from a rear portion of the body 1 via a connecting bracket 4, and a handle 6 and an operation panel section 7 that are gripped by an operator are provided at a distal end of the operation rod 5. The operation panel section 7 includes a forward / backward lever 8 that is turned forward when the front panel is tilted, a reverse position when the rear panel is tilted, and a neutral position when the vehicle is in the middle standing position, and an engine switch 9 for starting the engine. Installed.

A drive mechanism between the engine E and the hydraulic pump P is provided with a clutch mechanism 10 connected when the engine speed reaches a predetermined speed. As shown in FIG. A V-belt 13 is looped between a pulley 11 connected to the output shaft of the engine E via a mechanism 10 and a pulley 12 mounted on the input shaft of the hydraulic pump P. In the present embodiment, a centrifugal clutch is used as the clutch mechanism 10. However, a configuration that is connected when the engine speed reaches a predetermined speed as a result, such as an electromagnetic clutch that operates by detecting a voltage generated by the engine. The present invention does not particularly limit the structure and control form of the clutch as long as it has the following. The reason why the clutch mechanism 10 is interposed is as described above, and the hand guide roller H has a manual cranking mechanism (not shown) for starting the engine.

In FIG. 2, a hydraulic circuit relating to the traveling system of the hand guide roller H constitutes a closed circuit 14 by a hydraulic pump P and traveling hydraulic motors M1 and M2, and one hydraulic oil port Pa of the hydraulic pump P is connected to the traveling hydraulic pressure. The hydraulic oil port M1a of the motor M1 travels through the pipeline T1, and the other hydraulic oil port Pb of the hydraulic pump P and the hydraulic oil port M2a of the travel hydraulic motor M2 travel through the pipeline T2 with the hydraulic oil port M1b of the travel hydraulic motor M1. The hydraulic oil port M2b of the hydraulic motor M2 is connected to each other by a conduit T3. Accordingly, the closed circuit 14 generates the HST brake when the flow of the pressure oil is not occurring.

The hydraulic pump P is provided with the aforementioned forward / reverse lever 8.
Is tilted from the "neutral" position to the "forward position" or the "reverse position", whereby the angle of a swash plate (not shown) in the hydraulic pump P is switched, and the amount of pressure oil and the amount of pressure oil in the closed circuit 14 are changed. The flow is switched in the forward and reverse directions. Then, the traveling hydraulic motors M1 and M2 rotate forward and backward with the flow of the pressure oil in the forward and reverse directions, so that the hand guide roller H moves forward or backward. When the forward / reverse lever 8 is set to the "neutral" position, the swash plate is in the neutral position, the pump operation is stopped, and the oil passage in the hydraulic pump P is actively shut off, so that the hand guide roller H stops running. Becomes

In the closed circuit 14 of the present embodiment, the check valves 15, 16,
A high-pressure relief valve 17 and a manual switching valve 18 are interposed. Reference numeral Pc denotes a charge pump that rotates with the rotation of the hydraulic pump P and supplies pressure oil to the closed circuit 14, and is provided integrally with the hydraulic pump P. The suction port is connected to the oil tank 20 via a pipe T4 with a filter 19 interposed, and the discharge port is connected to a pipe T5. The pipe T5 is branched into a pipe T6 and a pipe T7, and the pipe T6 is connected to the oil tank 2 through the relief valve 21.
0 and the check valves 15, 16
Connected between. As a result, the charge pump Pc
Pipe line T which has become low pressure through check valve 15 or 16
Replenish the insufficient flow of pressure oil to one of T1 and T2.

The pipe T7 branches into a pipe T8 and a pipe T9 via a three-port electromagnetic switching valve 22, one pipe T8 is connected to the oil tank 20, and the other pipe T9 is running. It is connected to the pressure oil port 24 of the negative brake mechanism 23 in the hydraulic motor M2. When the engine E is driven, the switching valve 22 is in a state where the solenoid is excited and the line T7 is connected to the line T9. Therefore, at this time, the negative brake mechanism 23 receives the supply of the pressure oil from the charge pump Pc and The brake is released.

The traveling hydraulic motor M2 is, as shown in FIG.
On the fixed part 25 side, the output part 28 side, which is fastened and fixed to the bracket 1 a attached to the body 1 with a bolt 26 at the flange part formed on the outer periphery thereof and is rotatable with respect to the fixed part 25 via the bearing 27, , Bolts 29 are fastened and fixed to a head plate 30 fixed in the rear roll 3. In this embodiment, the traveling hydraulic motor M2 is a known orbit motor (registered trademark). To explain the schematic structure,
As shown in FIG. 6, a giroller ring 31 having a hollow portion having a substantially star-shaped cross-section so as to have a plurality of internal teeth (seven teeth in FIG. 6) is fixed to the fixed portion 25 side. A girola star 32 having a substantially star-shaped cross section and having a number of teeth (six in the figure) one less than the number of internal teeth of the girola ring 31 is mounted on the outer periphery of the portion. A spline groove is formed on the inner periphery of the girler star 32, and one end of the drive 33 is spline-coupled to the spline groove as shown in FIG. The other end of the drive 33 is spline-coupled to a spline groove of a shaft 34 fixed to the output unit 28 side. Note that a planetary reducer 35 is attached to the shaft 34.

As described above, the pressure oil port M2a or M2b
When the pressurized oil flows into the girola ring 31 through (FIG. 2), the girella star 32 slides on the internal teeth of the girola ring 31 and revolves (the locus of the center of the girella star 32 is denoted by reference character O). ), And only the rotation is taken out by the drive 33, and the output unit 28, that is, the rear roll 3 is rotated via the shaft 34. The traveling hydraulic motor M1 attached to the front roll 2 side
Has the same configuration as that of the traveling hydraulic motor M2 except that the negative hydraulic brake system does not include the negative brake mechanism 23.

The structure of the negative brake mechanism 23 is not particularly limited, such as a disk type, but the present embodiment is a pin-lock type brake mechanism having a simple structure. A piston cover 36 that forms a brake oil chamber is attached to an end of the fixed portion 25. The piston pin 37 having a pin portion 37a formed on a head surface portion 37b and a piston pin 37 formed in the piston cover 36 are provided on the drive 33 side. A compression spring 38 constantly biased toward the housing is housed. The pressure oil port 24 is provided so as to face the head part 37 b of the piston pin 37. On the other hand, drive 33
An engagement hole 33a into which the pin 37a can be inserted is formed in the end face on the one end side.

With the above structure, when the pressure oil is not supplied, the piston pin 37 is pressed toward the drive 33 by the urging force of the compression spring 38, and the drive 3
When the pin 3 rotates and the engaging hole 33a reaches a predetermined position on the locus O, the pin 37a is inserted into the engaging hole 33a to lock the rotation of the drive 33 and apply the brake. Also, the charge pump Pc is activated to operate the pressure oil port 2
When the pressurized oil flows in from 4, the pressurized oil presses the piston pin 37 at the position of the head surface portion 37b in a direction away from the drive 33 against the urging force of the compression spring. As a result, as shown in FIG.
The drive 33 is unlocked and the brake is released.

Now, the hand guide roller H is provided with a detecting means 41 capable of detecting the stop state of the engine E and a detecting means 4.
A stopping means for stopping supply of pressure oil to the negative brake mechanism when the engine detects a stop state of the engine; Here, an engine oil pressure sensor that detects the pressure of engine oil (lubricating oil) when the engine is driven is attached to the hand guide roller for the purpose of preventing seizure of the engine. Warning lamps and buzzers alert workers. In this embodiment, the detecting means 4
1 uses this engine oil pressure sensor. In the case of a hand guide roller, the pressure value of the engine oil when the engine is driven is usually 9.8 × 10 ⁻² MPa.
Has a ~4.4 × 10 ^-1 MPa, when the pressure value is reduced to 1.96 × 10 ^-2 MPa in the present embodiment, an engine oil pressure sensor 4 as an engine E is stopped
6 (FIG. 3).

Other examples of the detecting means 41 include a method of detecting a voltage and a current from a power generating coil of the engine, a method of using an engine speed sensor, and a method of detecting an intake pressure of the engine. However, by using a sensor for detecting the engine oil pressure as in the present embodiment, a simple electric circuit can be used as the detecting means and an economical hand guide roller can be obtained.

The stopping means 42 is configured as follows. In FIG. 3, the S terminal of the engine switch 9 and the B terminal
The terminals are connected to a start terminal S and a battery input terminal B of the starter 43, respectively. The voltage generated by the generator 44 is output from its terminal via a regulator 45, and this terminal is connected to the M terminal of the engine switch 9. That is, the M terminal is a terminal to which a voltage is applied when the generator 44 is generating power. Stopping means 4
Reference numeral 2 denotes a configuration in which the solenoid S1 of the switching valve 22 is connected to the M terminal via a wiring 51 via a relay R1, and the exciting coil of the relay R1 is connected to the M terminal and the engine oil pressure sensor 46. .

Next, the operation of the present invention will be described.
First, the state in which the compaction work is normally performed while the hand guide roller H moves forward or backward will be described. The hydraulic pump P is rotated by the drive of the engine E via the clutch mechanism 10, and the lever 8 is located at the “forward position” or the “reverse position” and the oil passage in the hydraulic pump P is in an open state, so that the hydraulic pump P generates a flow of pressurized oil in the closed circuit 14 by the pump action. As a result, the traveling hydraulic motors M1 and M2 rotate, and the hand guide roller H moves forward or backward.

At this time, since the coil of the relay R1 is energized and the wiring 51 is conducted (closed state), the switching valve 22 excites the solenoid S1 and connects the line T7 to the line T9. In this state, the pressure oil is supplied to the negative brake mechanism 23 through the paths of T5, T7, and T9 by the charge pump Pc that rotates with the rotation of the hydraulic motor P, and as shown in FIG. 37a is the engagement hole 33a of the drive 33
And the brake is in the released state.

Next, a description will be given of a case where the engine E suddenly stops due to an engine trouble, running out of fuel, or the like during compaction work on a slope, for example. When the engine speed drops to a predetermined speed, the clutch mechanism 10 is stopped. Are disconnected, and the engine E and the hydraulic pump P are disconnected. At this time, the conventional hand guide roller rotates the traveling hydraulic motor in an attempt to suddenly run on the slope by its own weight, and the hydraulic pump P (and the charge pump Pc) that has lost the load on the engine E is pumped by the traveling hydraulic motor. As described above, there is a risk of rotation in response to this.

However, in the hand guide roller H according to the present invention, the following operations occur. When the engine E is stopped, the engine oil pressure becomes a predetermined pressure value (1.96 in this embodiment).
When the pressure drops to × 10 ^-2 MPa), the engine oil pressure sensor 46 operates to open the relay R1, and thus the solenoid S1 is de-energized, so that the switching valve 22 connects the pipes T8 and T9. It switches to the side to do. That is, the supply of the pressure oil from the charge pump Pc to the negative brake mechanism 23 is forcibly stopped. Then, the pressure oil remaining in the piston cover 36 is returned to the oil tank 20 through the pipes T9 and T8, so that the pin portion 37a of the piston pin 37 is inserted into the engagement hole 33a of the drive 33. The fitting brake is applied, and sudden running of the hand guide roller H is prevented.

The hand guide roller H uses the V belt 13 together with the clutch mechanism 10 as drive transmission between the engine E and the hydraulic pump P as described above.
Even if the V-belt 13 breaks during compaction work on a slope, the hydraulic pump P, which has also lost the engine brake of the engine E, rotates by receiving the pumping action of the traveling hydraulic motors M1 and M2, The charge pump Pc also rotates, and the brake of the negative brake mechanism 23 does not operate, so that the hand guide roller H may suddenly go down the slope. Reference numeral 47 in FIG. 3 indicates a brake switch for solving the problem,
It functions to stop the supply of the pressure oil to the negative brake mechanism 23 regardless of the stop state. The brake switch 47 is a push-button type two-circuit, two-contact switch provided on the operation panel unit 7 as shown in FIG. 1, and is located between the M terminal of the wiring 51 and the relay R1 on the electric circuit. The C terminal, which is a common terminal, is connected to the M terminal of the engine switch 9, and the NC (normally closed) terminal is connected to the relay R1.

Normally, the brake switch 47 is in a state where the C terminal and the NC terminal are connected as shown in FIG. Then, for example, when the V-belt 13 suddenly breaks during the compaction work on a slope and the hand guide roller H tries to go down the slope, when the operator presses the brake switch 47 to operate the switch, the brake switch is activated. 47 is connected between the C terminal and the NO (normally open) terminal. Therefore, when the solenoid S1 is de-energized, the switching valve 22 is switched to the side that connects the pipeline T8 and the pipeline T9. The following operation is the same as that of the stopping means 42 described above, and the pressure oil remaining in the piston cover 36 is returned to the oil tank 20 via the pipes T9 and T8, so that the piston pin 37 The pin portion 37a is inserted into the engagement hole 33a of the drive 33 to apply a brake, thereby preventing the hand guide roller H from running suddenly.
The brake switch 47 is not limited to a push button type, but may be a toggle type switch or a rotary switch. With such a configuration provided with the brake switch 47, the switch operation is compared with the lever operation of rotating the forward / reverse lever 8 from the "forward position" or the "reverse position" to the "neutral" position in the upright state. Therefore, the operator can easily operate the brake switch 47 even with the hand guide roller that has started to go down the slope suddenly, and the negative brake mechanism 23 can be braked.

Further, the hand guide roller H is driven by the engine E
In the case where a diesel engine is mounted, the engine does not stop even if the engine switch 9 is turned off, so that the pressure oil flows through the closed circuit 14 and the negative brake mechanism 23 does not perform the braking operation. Therefore,
Even when the engine switch 9 is turned off, if the supply of the pressure oil to the negative brake mechanism 23 is stopped, this is effective for a vehicle equipped with a diesel engine.

The preferred embodiment of the hand guide roller according to the present invention has been described above. However, each constituent means is not limited to the contents described in the drawings, and the design can be changed as appropriate without departing from the spirit of the present invention. It is.

[0036]

According to the present invention, the following effects can be obtained. (1) If the configuration is provided with a detecting means capable of detecting the stop state of the engine and a stopping means for stopping the supply of the pressure oil to the negative brake mechanism when the detecting means detects the stop state of the engine, the slope can be provided. Even if the engine suddenly stops during compaction work, etc., the negative brake mechanism performs braking operation reliably, so that it does not suddenly start to descend on a slope, and a highly safe hand guide roller can be constructed . (2) If the detecting means is constituted by an engine oil pressure sensor for detecting the engine oil pressure, a simple electric circuit is sufficient and an economic hand guide roller can be obtained. (3) Also, set the engine switch for starting the engine to OF
If the configuration is such that the supply of the pressurized oil to the negative brake mechanism is stopped at the time of F, it is effective when the hand guide roller is a vehicle equipped with a diesel engine. (4) Further, if a brake switch for stopping the supply of the pressure oil to the negative brake mechanism is provided irrespective of the driving state or the stopped state of the engine, for example, the V-belt breaks during compaction work on a slope. For example, even when the engine and the hydraulic pump are disconnected while the engine is running, the negative brake mechanism performs a braking operation, so that a more secure hand guide roller can be constructed.

[Brief description of the drawings]

FIG. 1A is a plan view of a hand guide roller, and FIG. 1B is a side view of the same.

FIG. 2 is a hydraulic circuit diagram relating to a traveling system.

FIG. 3 is a sequence control circuit diagram showing a detecting unit and a stopping unit.

FIG. 4 is an explanatory side sectional view showing a traveling hydraulic motor and a negative brake mechanism.

FIG. 5 is an explanatory side sectional view showing a brake release state of the negative brake mechanism.

FIG. 6 is a structural sectional view of a main part when the traveling hydraulic motor is viewed from the front.

FIG. 7 is a hydraulic circuit diagram relating to a traveling system in a conventional hand guide roller.

[Explanation of symbols]

 E Engine H Hand guide roller M1, M2 Travel hydraulic motor P Hydraulic pump Pc Charge pump 1 Body 2 Front roll (travel roll) 3 Rear roll (travel roll) 8 Forward / reverse lever 9 Engine switch 10 Clutch mechanism 14 Closed circuit 22 Switching valve 23 Negative brake mechanism 41 Detecting means 42 Stopping means 46 Engine oil pressure sensor 47 Brake switch

Continued on the front page F term (reference) 2D052 AA03 AD04 AD13 AD17 BB01 BB10 3D046 AA06 CC01 CC02 EE02 GG02 HH03 HH16 HH17 LL14 LL37 LL43 3D048 AA05 BB07 CC64 HH15 HH44 HH60 HH66 HH67 KK09 KK06 Q

Claims (4)

[Claims] 1. A clutch mechanism connected when an engine speed reaches a predetermined speed, a hydraulic pump driven by an engine via the clutch mechanism, and a traveling hydraulic motor driving a traveling roll. A closed circuit that is formed; a charge pump that rotates with the rotation of the hydraulic pump to supply pressure oil to the closed circuit; and a negative brake mechanism that performs a braking operation when the supply of pressure oil from the charge pump is stopped. In the hand guide roller, a detection unit capable of detecting the stop state of the engine, and when the detection unit detects the stop state of the engine,
A hand stop roller for stopping the supply of pressure oil to the negative brake mechanism. 2. The hand guide roller according to claim 1, wherein said detecting means comprises an engine oil pressure sensor for detecting an engine oil pressure. 3. An engine switch for starting the engine is set to O.
3. The hand guide roller according to claim 1, wherein when the FF is set, the supply of the pressure oil to the negative brake mechanism is stopped. 4. 4. A brake switch for stopping supply of pressure oil to said negative brake mechanism irrespective of a driving state or a stopped state of said engine. The described hand guide roller.