JP3831864B2 - Output control device and power work machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an output control device for controlling the output of a prime mover and a power work machine including the output control device.
[0002]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that it is possible to quickly accelerate the prime mover, and to easily maintain the output of the prime mover at a predetermined set output level, and the power provided with the output control device. It is to provide a working machine.
[0003]
[Means for Solving the Problems]
    In order to solve the above-mentioned problem, an output control device according to the present invention described in claim 1 is a motor and an operation member for controlling the output of the motor., Non-operating position,An operation member having a predetermined operation position corresponding to a predetermined set output level of the prime mover, and temporarily setting the output of the prime mover in response to an operation of the operation member to the predetermined operation position. A transmission return mechanism for making the output larger and then returning the output of the prime mover to the set output level.,WithThe transmission control mechanism includes a first return chamber that defines a first fluid chamber and a second fluid chamber between each other and moves relative to each other to change a volume of the fluid chamber. A member, a second member, and a first member and the second member disposed between the first member and the second member so that their relative positions are maintained in an initial state corresponding to the non-operation position of the operation member. Always-acting biasing means, a large fluid passage hole for discharging the fluid in the first fluid chamber relatively rapidly, and a small fluid for discharging the fluid in the second fluid chamber relatively slowly And a check valve that allows the fluid to flow into the second fluid chamber when the fluid is discharged from the first fluid chamber, wherein the first member is the predetermined operation of the operation member. The operating member is driven simultaneously with the operation to the position The second member is operatively connected, and the second member is constantly urged in a direction to decrease the output of the prime mover, and is driven against the urging force so as to increase the output of the prime mover. The flow resistance that is operatively connected to the prime mover and is provided by the small fluid passage hole corresponds to the operation of the operation member, and the second member integrally with the first member outputs the output of the prime mover as the set output. It is set to such an extent that it is temporarily driven so as to be larger than the level, and further, between the first member and the second member, from the second fluid passage hole to the second fluid chamber. The stopper is provided to stop the change in the relative position of the second member with respect to the first member due to the outflow of the fluid, and to keep the output of the prime mover at the set output level.
[0004]
According to the present invention, when the operation member is operated to the predetermined operation position, the output of the prime mover temporarily exceeds the set output level by the transmission action of the transmission return mechanism. Therefore, the prime mover accelerates quickly. Thereafter, the output of the prime mover is automatically returned to the set output level and held by the return action of the transmission return mechanism. For this reason, the prime mover can be quickly accelerated only by operating the operating member to the predetermined operation position, and the output of the prime mover is automatically returned to the set output level, and the level can be easily set. It can be held.
[0005]
  Also,As the transmission return mechanismFlowUsing body circulation resistanceBecause we adopt the thingCompared to a transmission return mechanism using a mechanical or electrical control means, etc., there are advantages such as a simple structure that contributes to cost reduction, and is strong against shocks such as vibration and has good durability.
[0007]
  in frontThe operation memberFrom non-operating positionWhen operating to the predetermined operating position, the first member is simultaneously driven accordingly. At this time,secondSince the internal pressure of the fluid chamber is increased, the fluid in the fluid chamber issmallIt tries to flow out from the fluid passage hole. However, thesmallSince the flow resistance of the fluid passage hole is set to the predetermined level, the amount of fluid flowing out per unit time is small. Therefore, the second member is also driven integrally with the instantaneous driving of the first member, and thereby the output of the prime mover becomes larger than the set output level. However, since the second member is constantly urged in a direction that reduces the output of the prime mover, the fluid in the second fluid chamber issmallThe second member gradually flows out from the fluid passage hole, and gradually returns in the direction of decreasing the output of the prime mover. Eventually, the stopper stops the change in the relative position of the second member with respect to the first member, and the output of the prime mover is maintained at the set output level.Next, when the operation member is returned to the non-operation position, the second member is constantly urged in a direction to decrease the output of the prime mover, whereby the first member and the second member are These members are returned together while keeping their relative positions constant. At the same time, the relative position of the first member and the second member returns to the initial state by the action of the biasing means. In this returning operation, the check valve is opened by increasing the volume of the second fluid chamber due to the action of the urging means, and the fluid in the first fluid chamber flows from the large fluid passage hole. It is completed instantly and reliably by being quickly discharged.
[0008]
  Claim2For example, the first member is formed by one of a cylinder member and a piston member that are slidably fitted to each other, and the second member is formed by the cylinder member and the piston. It is preferable to form with the other of the members.
[0009]
  Claim3The output control apparatus according to the present invention described in claim 1Or 2An automatic return-type operation member that automatically returns to a predetermined non-operation position where output to the power work member of the prime mover is cut off when the operation member is released from the predetermined operation position. And an operation position fixed operation member capable of adjusting the set output level of the prime mover when the automatic return operation member is operated to the predetermined operation position.
[0010]
  Claim4A power working machine according to the present invention described in claim1, 2 or 3And a power working member that is connected in driving to the prime mover.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of the invention will be described with reference to the accompanying drawings.
[0012]
1 is an overall schematic perspective view showing a brush cutter as an example of a power working machine including an output control device according to an embodiment of the present invention, and FIG. 2 is an overall perspective view of a throttle lever device in FIG. 3 is an exploded perspective view of FIG. 2, FIG. 4 is a perspective view of the main part of the throttle lever device, and FIG. 5 is a partial cross-sectional view of the throttle lever device including a cross-section taken along the line V-V of FIG. 6 is an explanatory diagram showing an operating force transmission system between the throttle lever device and the carburetor.
[0013]
First, referring to FIG. 1, the brush cutter has a rotary cutting blade 2 as a power working member at a front end portion of the operation rod 1 extending in the front-rear direction, and a rear end portion of the operation rod 1. Moreover, for example, a small air-cooled two-cycle internal combustion engine 3 is provided as a prime mover. The driving force by the internal combustion engine 3 is transmitted to the cutting blade 2 through a transmission shaft 4 inserted into the operation rod 1. An appropriate type of centrifugal clutch 5 is interposed between the internal combustion engine 3 and the transmission shaft 4. When the rotational speed of the internal combustion engine 3 exceeds a predetermined value, the rotational driving force is reduced. This is output to the cutting blade 2.
[0014]
A hanging bracket 6 is attached to a portion of the operating rod 1 close to the internal combustion engine 3. By hanging a shoulder belt (not shown) on the hanging metal fitting 6, the operator can hold the brush cutter with a good balance on the shoulder.
[0015]
On the operation rod 1, two front and rear grip portions 7 and 8 are provided, each of which mainly uses rubber having good vibration absorption. Normally, in the vicinity of the front grip portion 7 held by the left hand of the operator, the cutting blade 2 is braked to a position where the brake can be released with fingers while holding the front grip portion 7. A brake lever device 9 is attached. The brake lever device 9 is operatively connected to a brake device 56 disposed in the cutting blade 2 part via a brake driving force transmission cable 55. The brake lever device 9 instantaneously stops the rotation due to the inertia of the cutting blade 2 when the internal combustion engine 3 is decelerated so that the centrifugal clutch 5 is disconnected and the driving of the cutting blade 2 is stopped. This is to increase the safety of the brush cutter.
[0016]
On the other hand, in the vicinity of the rear grip portion 8 that is normally gripped by the operator's right hand, a throttle lever is located at a position where the internal combustion engine 3 can be increased / decreased with fingers while holding the rear grip portion 8. A device 10 is attached.
[0017]
As clearly shown in FIG. 6, the throttle lever device 10 is a throttle of the carburetor 12 which is an output control member of the internal combustion engine 3 through a throttle operation Bowden cable 11 which can be pushed and pulled. Operationally connected to the valve 12a. In the present embodiment, as the vaporizer 12, a float type with a piston valve, which is known per se, is illustrated. The throttle valve 12a is constantly urged in a direction to automatically return to the idle rotation opening degree by an urging means such as a throttle valve return spring 60, and the throttle operation Bowden cable 11 connected thereto is connected. When the inner wire 13 is pulled for a predetermined length or more from the non-operating state by the grip operation of the throttle lever device 10, there is no play in the inner wire 13, and the throttle valve 12a is moved from the idle rotational opening to the internal combustion engine 3. It starts to open in the direction of increasing speed (output increasing).
[0018]
As shown in FIG. 2, in this embodiment, the throttle lever device 10 having two throttle levers 14 and 15 of different types is employed. These two throttle levers 14 and 15 are output operation members for controlling the output of the internal combustion engine 3 to the cutting blade 2 by controlling the opening and closing of the throttle valve 12a. Here, the one main throttle lever 14 is an automatic return type, and the other sub throttle lever 15 is an operation position fixed type. That is, the main throttle lever 14 automatically returns to the original non-operating position P1 (see FIG. 6) together with the throttle valve 12a when the hand holding it is released and released. The throttle lever 15 is of a type that can be held in a desired operation position in an immobile state. As described above, the two throttle levers 14 and 15 having different types are provided because the main throttle lever 14 of the automatic return type is always used regardless of the output level to the cutting blade 2. So that the throttle lever device 10 can be used while being held at a stable predetermined maximum operation position P2 (see FIG. 6). This is to increase safety.
[0019]
That is, conventionally, as a throttle lever type, an automatic return type and an operation position fixed type have been proposed, both of which have advantages and disadvantages.
[0020]
Specifically, the automatic return lever has the advantage that it is safe because the internal combustion engine automatically returns to the idling state when the hand is released. Since the lever must be held with a finger at all times and maintained at a desired operation position, when used at an intermediate opening, the finger becomes tired and the output to the cutting blade is not constant. There is.
[0021]
On the other hand, according to the lever with the fixed operation position, it can be held in a fixed state even if it is released to the desired operation position, so that the fingers are free and the workability is good, the output is constant, and the fingers are tired. However, when stopping output to the cutting blade, an intentional operation is required to put the finger on the lever and return it to the idle position. As a result, there is a problem that the output to the cutting blade cannot be stopped immediately, which is inferior to the automatic return type in terms of safety.
[0022]
Therefore, in the present embodiment, the automatic return type lever and the operation position fixed type lever are combined, and the throttle lever device having high operability and high safety is obtained by taking advantage of only the advantages thereof. is there.
[0023]
As shown in FIG. 2, the throttle lever device 10 includes a throttle lever case member 16 that supports the main throttle lever 14 and the sub-throttle lever 15 in a swingable manner. The throttle lever case member 16 includes a left cover case 18 and a right cover case 19 that are coupled to each other with a plurality of screws 17 so as to sandwich the operation rod 1 from the left and right, and in front of the rear grip 8. Located adjacent to it.
[0024]
Similarly, as shown in FIG. 2, a sliding stop switch for stopping the internal combustion engine 3 by short-circuiting energization to the ignition plug 22 (see FIG. 1) of the internal combustion engine 3 is provided in the throttle lever case member 16. 23 is provided. A conductive cord (not shown) extending from the switch 23 passes through the inside of the rear grip portion 8 together with the throttle operation Bowden cable 11 from the inside of the throttle lever case member 16 toward the internal combustion engine 3 side. It is pulled out backwards.
[0025]
As shown in FIG. 6, the main throttle lever 14 has the non-operation position P1 indicated by a solid line in FIG. 6 and the maximum operation position P2 indicated by a two-dot chain line in FIG. , And can be swung freely. When the main throttle lever 14 is in the non-operation position P1, the operation portion 20 is moved from the lower position of the rear portion of the throttle lever case member 16 to below the rear grip portion 8 as shown in FIG. It extends obliquely downward at a predetermined angle. On the other hand, when the main throttle lever 14 is at the maximum operation position P2, the operation portion 20 is fitted into a lever housing concave groove 21 formed at a lower portion of the rear grip portion 8, and the rear grip portion The cross section including the outer shape of FIG. For this reason, grip operability is good. The main throttle lever 14 is urged by a main throttle lever return spring 61 (see FIG. 3) or the like so that the operation portion 20 is held at the non-operation position P1 farthest downward from the rear grip portion 8. Always energized by means.
[0026]
In FIG. 3, the main throttle lever 14 is curved forward and upward from a portion of the cylinder portion 25 that receives the pivot shaft 24 in a relatively rotatable manner, in addition to the operation portion 20. And an extended lever action portion 26. It is preferable that the lever lever 26 has a shape that is appropriately curved in the left-right direction so as to avoid interference with the outer peripheral shape of the operating rod 1 because the throttle lever device 10 is compact. The pivot shaft 24 of the main throttle lever 14 extends horizontally in the left-right direction, and both left and right outer ends thereof are supported by the left and right cover cases 18 and 19 as lightly press-fitted.
[0027]
In the present embodiment, as shown in FIGS. 4 and 6, the throttle 20 is operated by rotating the operation portion 20 of the main throttle lever 14 upward from the non-operation position P1 to the rear grip portion 8 side. The inner wire 13 of the operation Bowden cable 11 is pulled forward of the operation rod 1 via an output control amount enlargement mechanism 27 and a pulley 28 as a turning member.
[0028]
The output control amount increasing mechanism 27 increases the opening / closing amount of the throttle valve 12a corresponding to the operation amount of the main throttle lever 14 and the sub throttle lever 15, and this is provided for the main throttle. This is because the occupied area for the rotation operation of the lever 14 and the sub-throttle lever 15 is reduced, and the throttle lever device 10 is made as compact as possible.
[0029]
For example, as shown in FIG. 4, the output control amount enlarging mechanism 27 includes a lever member 30 supported by a support shaft 29 extending in the vertical direction so as to be horizontally swingable. The upper and lower ends of the support shaft 29 of the lever member 30 are supported inside the right cover case 19 (see FIG. 3).
[0030]
As shown in FIGS. 3 and 4, the front end of the inner wire 13 of the throttle operation Bowden cable 11 is disposed at the distal end portion (left end portion) of the long swing arm 31 that is the left half of the lever member 30. An end fitting 32 attached to the portion is fitted and locked. As shown in FIG. 6, the front end portion of the outer tube 33 of the throttle operation Bowden cable 11 is fixed to the throttle lever case member 16.
[0031]
On the other hand, one end fitting 36 of a folding wire 35 as a flexible interlocking member is fitted into the distal end portion (right end portion) of the short-side swing arm 34 that is the right half of the lever member 30 to be locked. Has been. The folding wire 35 is wound around the pulley 28 from below and folded forward, and the other end fitting 37 is fitted into the distal end portion of the lever operating portion 36 of the main throttle lever 14. Are locked.
[0032]
In the output control amount enlarging mechanism 27 shown in FIG. 4, when the operation portion 20 of the main throttle lever 14 is rotated upward toward the rear grip portion 8, the lever member 30 swings on the short side. The arm 34 is pulled rearward through the folding wire 35, and the lever member 30 rotates in the clockwise direction when viewed from above. Accordingly, the long-side swing arm 31 of the lever member 30 is rotated. Thus, the inner wire 13 of the throttle operation Bowden cable 11 is drawn forward. In this case, the lever ratio of the lever member 30 increases the amount of tension of the inner wire 13 of the throttle operation Bowden cable 11 by the main throttle lever 14, and the opening / closing control of the throttle valve 12 a by the main throttle lever 14. The amount is expanded. For this reason, the opening / closing control of the throttle valve 12a can be performed by a small operation of the main throttle lever 14, and the apparatus can be reduced in size and weight.
[0033]
Further, in the present embodiment, the pulley 28 is forcibly moved in the direction of pulling the inner wire 13 of the throttle operation Bowden cable 11 and the direction of loosening it (front-rear direction) so that it does not move at any adjustment position. A pulley position adjusting mechanism 38 for maintaining the state is provided.
[0034]
For example, as shown in FIG. 5, the pulley position adjusting mechanism 38 supports the pulley 28 so as to be rotatable and swings itself, and swings the swinging body 39. The sub-throttle lever 15 is provided.
[0035]
The swing body 39 is supported inside the right cover case 19 so as to be swingable in the front-rear direction about a pivot axis Z extending in the left-right direction. Here, the bearing portion 40 formed on the right cover case 19 supports the right shaft portion 41 of the rocking body 39, and the bearing portion 43 formed on the intermediate member 42 separate from the right cover case 19 The left shaft portion 44 of the rocking body 39 is supported, and the intermediate member 42 is attached to the right cover case 19.
[0036]
The sub-throttle lever 15 is fixed to the right shaft portion 41 of the rocking body 39 that protrudes rightward from the right cover case 19. In the illustrated example, a serration portion 45 is formed on the outer periphery of the front end portion of the right shaft portion 41 of the rocking body 39, and a serration portion 46 fitted therewith is also formed on the sub-throttle lever 15. , 46 are fitted together, and the sub-throttle lever 15 is integrally fixed to the rocking body 39 with a screw 47.
[0037]
The pulley 28 is housed in a pulley housing portion 48 formed on the rocking body 39. The support shaft 49 of the pulley 28 is press-fitted and supported by the rocking body 39 and extends in parallel with the pivot axis ZZ of the rocking body 39. Further, the central axis Y of the support shaft 49 is located upward by a predetermined distance D from the pivot axis ZZ of the rocking body 39. Therefore, the pulley 28 is moved in the front-rear direction by swinging the sub-throttle lever 15 in the front-rear direction, and the pulling operation and the return operation of the inner wire 13 of the throttle operation Bowden cable 11 are performed. Can do.
[0038]
As shown in FIG. 5, a push button shaft 50 is provided on the sub throttle lever 15 so as to be slidable in the vertical direction. The push button shaft 50 is inserted into a push button sleeve 51 formed integrally with the sub-throttle lever 15 and is always urged upward by a compression coil spring 52 interposed in the push button sleeve 51. The upper end portion 50a protrudes upward from the push button sleeve 51. Further, the lower end portion of the push button shaft 50 protrudes downward from the push button sleeve 51 and is bent to the left side, and a sawtooth movable side tooth portion 53 is integrally formed upward. . On the other hand, a sawtooth fixed side tooth portion 54 with which the movable side tooth portion 53 meshes is integrally formed downward on the upper side of the right cover case 19. As shown in FIG. 3, the fixed tooth portion 54 is formed in the front-rear direction so as to draw an arc centered on the pivot axis ZZ of the sub-throttle lever 15.
[0039]
In the pulley position adjusting mechanism 38 shown in FIG. 5, when the upper end portion 50 a of the push button shaft 50 is pressed, the push button shaft 50 is lowered, and the movable side tooth portion 53 and the fixed side tooth portion 54. The meshing state is released. Therefore, when the sub-throttle lever 15 is rotated backward while the pushbutton shaft 50 is being pressed, the pulley 28 pulls the inner wire 13 of the throttle operation Bowden cable 11 (rear of the operation rod 1). ). In this state, when the pressing of the push button shaft 50 is released, the movable side tooth portion 53 is reengaged with the fixed side tooth portion 54 at a new position of the fixed side tooth portion 54, and the sub-throttle lever 15. And the pulley 28 are held at the rotation operation position at that time.
[0040]
Since the pulley 28 acts as a moving pulley, when the pulley 28 is moved, the inner wire 13 of the throttle operation Bowden cable 11 is pulled by a length twice as much as the movement amount. Therefore, in addition to the operation of the output control amount expansion mechanism 27, the opening / closing control amount of the throttle valve 12a is further expanded. Therefore, the opening / closing control of the throttle valve 12a can be performed by a small operation of the sub-throttle lever 15. Thus, the apparatus can be reduced in size and weight.
[0041]
The front / rear swinging width of the sub-throttle lever 15 is regulated within a predetermined angle range. That is, the sub-throttle lever 15 has a maximum forward operation position where the pulley 28 brings the inner wire 13 of the throttle operation Bowden cable 11 into the non-operating state, and the pulley 28 allows the play of the inner wire 13 to move. It can be swung between the maximum backward operation position to be eliminated. Then, the sub-throttle lever 15 is swung to the maximum rearward operation position (there is no play of the inner wire 13), and in this state, the main throttle lever 14 is swung to the maximum operation position P2. When the operation is performed, the output level of the internal combustion engine 3 becomes maximum (full throttle state). When the main throttle lever 14 is released from this state, the main throttle lever 14 automatically returns to the non-operation position P1, and the internal combustion engine 3 enters an idling state.
[0042]
The throttle lever device 10 is used as follows, for example. Now, it is assumed that the brush cutter is in an inoperative state and the sub-throttle lever 15 is in the maximum forward operation position (therefore, the inner wire 13 is in a non-operation state). At this time, the play (loosening) of the inner wire 13 of the throttle operation Bowden cable 11 is maximized.
[0043]
The operator performs a start operation of the internal combustion engine 3 with a recoil starter 3a (see FIG. 1), and when the internal combustion engine 3 is in an idling state, the operator holds the brush cutter on the shoulder with the shoulder belt, and the rear grip The main throttle lever 14 is gripped together with the portion 8, and the main throttle lever 14 is swung to the maximum operation position P2. Then, the inner wire 13 of the throttle operation Bowden cable 11 is pulled for a predetermined length via the output control amount enlargement mechanism 27 and the pulley 28. For example, there is no play of the inner wire 13, and the throttle wire The valve 12a starts to open, and a small output that does not connect the centrifugal clutch 5 is started.
[0044]
Next, the operator presses the upper end portion 50a of the push button shaft 50 with the thumb of the hand holding the rear grip portion 8 while holding the main throttle lever 14 at the maximum operation position. The sub throttle lever 15 is tilted to the rear of the operating rod 1 so that the output to the cutting blade 2 is raised to a desired level. Then, the pulley 28 is forcibly displaced rearward, and the inner wire 13 of the throttle operation Bowden cable 11 is pulled by a length corresponding to twice the moving amount, so that the throttle valve 12a is opened. The degree is adjusted in the fully open direction, and the output of the internal combustion engine 3 to the cutting blade 2 is increased.
[0045]
Since the sub-throttle lever 15 is held in a desired operation position by the meshing of the movable side tooth portion 53 and the fixed side tooth portion 54, the operator can set the output by the sub-throttle lever 15. Can be released from the sub throttle lever 15. Therefore, the burden on the operator's fingers is reduced. While the operator is holding the main throttle lever 14 together with the rear grip 8, the operator operates the operating rod 1 and swings the cutting blade 2 to the left and right. Just work.
[0046]
The operator releases the main throttle lever 14 when the internal combustion engine 3 is returned to the idling state in order to temporarily interrupt the brushing operation. Then, due to the biasing force of the throttle valve return spring 60, the throttle valve 12a is automatically and instantaneously returned to the idling rotational opening, the centrifugal clutch 5 is disengaged, and the cutting blade of the internal combustion engine 3 is released. Output to 2 stops.
[0047]
When the brushing operation is resumed from the idling state of the internal combustion engine 3, the operator grasps the operation portion 20 of the main throttle lever 14 to the maximum operation position P2 to the full. Then, the engine output at the same level as the output set up to that point by the sub-throttle lever 15 is automatically obtained. Therefore, the cutting blade 2 can be rotationally driven at the same speed as before, and the mowing operation can be resumed.
[0048]
As described above, according to the brush cutter, when used in a work environment in which the output level of the internal combustion engine 3 to the cutting blade 2 does not need to be frequently changed, When the main throttle lever 14 can be used at the maximum operating position P2, which is always a stable operating position, and it is desired to change the output level of the internal combustion engine 3 to the cutting blade 2 once set. The sub-throttle lever 15 of the operation position fixed type may be operated. Therefore, it is not necessary to use the main throttle lever 14 in an unstable intermediate operation position, and there is no fatigue of the operator's fingers, so that workability is good and if the main throttle lever 14 is released, the internal combustion engine Since the engine 3 returns to the idling state instantaneously and the output to the cutting blade 2 is stopped, the operability when the output to the cutting blade 2 is stopped is good and the safety is high.
[0049]
By the way, in the brush cutter as described above, when the operation position of the sub throttle lever 15 is adjusted to an arbitrary intermediate operation position ahead of the maximum rear operation position, the main throttle lever 14 is fully extended. Even if it is gripped and operated to the maximum operating position P2, the output of the internal combustion engine 3 does not reach the full throttle state. For this reason, problems such as an extra acceleration time than that of the conventional system are also expected. In general, for example, when the output of an internal combustion engine is controlled by an automatic return type throttle lever, the operator temporarily operates the throttle lever large to obtain a good engine acceleration at the time of startup. Usually, the internal combustion engine is blown to full throttle, and then the operation position of the throttle lever is returned to the intermediate operation position corresponding to the desired output level so that the output of the internal combustion engine is brought to the desired level. is there.
[0050]
Therefore, in the output control device according to the present embodiment, the engine acceleration is the same as in the conventional general case.BlowingIn order to obtain a scare effect, a transmission return mechanism described in detail below is employed.
[0051]
6 and 7 show a first embodiment of the transmission return mechanism. As shown in FIG. 6, the transmission return mechanism 62 is interposed in an operating force transmission system between the throttle lever device 10 and the throttle valve 12a of the carburetor 12, for example, as shown in FIG. Thus, it arrange | positions in the position which does not become the trouble of the brushing work by the said brush cutter, such as the rear end position of the said operating rod 1.
[0052]
That is, in the illustrated example, the throttle operation Bowden cable 11 is divided into a lever side Bowden cable 63 and a throttle valve side Bowden cable 64, and the transmission return mechanism is provided between these two cables 63, 64. 62 is interposed. As clearly shown in FIG. 6, the casing 65 of the transmission return mechanism 62 has a rear end portion 66a of the outer tube 66 of the lever side Bowden cable 63 and a throttle valve side at positions facing each other. The front end 67a of the outer tube 67 of the Bowden cable 64 is fixed to each other.
[0053]
For example, a cylinder member 69 as a first member having a cylinder hole 68 having a uniform inner diameter is accommodated in the casing 65 such as a split-type casing so as to be movable in a predetermined stroke or more in the axial direction thereof. A piston member 70 as a second member that can reciprocate along the axis is fitted and inserted into 68. A seal member such as an O-ring 71 is mounted on the outer peripheral surface of the piston member 70 in order to maintain airtightness and appropriate sliding resistance with the inner peripheral surface of the cylinder hole 68. A rear end 73a of the inner wire 73 of the lever side Bowden cable 63 is connected to one end side end plate 72 of the cylinder member 69, and the other end side end plate 74 of the cylinder member 69 passes through the piston member 70. The front end portion 75a of the inner wire 75 of the throttle valve-side Bowden cable 64 is connected. Between the inner wire 75 of the throttle valve side Bowden cable 64 and the wire insertion hole 76 of the end plate 74 of the other end of the cylinder member 69, airtightness between them is maintained and the inner wire is maintained. An appropriate seal member 77 that allows movement in the length direction of 75 is interposed.
[0054]
The piston member 70 divides the inside of the cylinder member 69 into two air chambers (fluid chambers) 78 and 79, and the piston member 70 moves between the piston member 70 and the cylinder member 69 due to the movement of the piston member 70. The volume of the two air chambers 78 and 79 defined is changed. The first air chamber 78 located on the throttle lever device 10 side (the volume is zero in the state of FIG. 6) is passed through a large vent hole 80 formed in the one end side end plate 72 of the cylinder member 69. It communicates with the internal space 65a of the casing 65 having air permeability. Ventilation resistance (flow resistance) due to the large ventilation hole 80 is extremely small and sufficient to allow instantaneous relative movement of the piston member 70 or the cylinder member 69 in the direction of reducing the volume of the first air chamber 78. The amount of ventilation is guaranteed by the large ventilation hole 80.
[0055]
On the other hand, the second air chamber 79 located on the throttle valve 12a side allows the inflow of air into the second air chamber 79 and prevents the outflow of air from the second air chamber 79. The valve 81 communicates with the internal space 65 a of the casing 65. The check valve 81 is attached to an extended vent 82 extending outward of the cylinder member 69 so as not to hinder reciprocal sliding of the piston member 70 in the cylinder hole 68. .
[0056]
The piston member 70 is provided with a small air hole 83 that allows the first air chamber 78 and the second air chamber 79 to communicate with each other as a fluid passage hole. The ventilation resistance (flow resistance) by the small vent 83 is large, and the relative movement of the piston member 70 or the cylinder member 69 in the direction of reducing the volume of the second air chamber 79 causes the fluid in the small vent 83 to flow. The throttle action restricts the speed to a very moderate speed.
[0057]
Means always exerting an urging action between the piston member 70 and the cylinder member 69 so as to keep the relative position between them in the initial state corresponding to the non-operation position P1 of the main throttle lever 14. For example, an initial state holding compression coil spring 84 is interposed. The biasing force by the initial state holding compression coil spring 84 is smaller than the biasing force by the throttle valve return spring 60 transmitted to the piston member 70 through the inner wire 75 of the throttle valve side Bowden cable 64. Is set to
[0058]
The operation of the transmission return mechanism 62 will be described with reference to FIGS. FIG. 7 is an explanatory view showing the operation of the transmission return mechanism 62 in time series. As shown in FIG. 7, in the transmission return mechanism 62, the relative positions of the piston member 70 and the cylinder member 69 with respect to the casing 65 and the members 69, 70 in accordance with the operation of the main throttle lever 14. The relative position between changes.
[0059]
Now, it is assumed that the internal combustion engine 3 is in an idling state and the position of the sub-throttle lever 15 is adjusted to the intermediate operation position ahead of the maximum rear operation position. In this state, when the main throttle lever 14 is in the non-operation position P1 shown by a solid line in FIG. 6, a little play remains on the inner wire 13 of the throttle operation Bowden cable 11 as a whole. The throttle valve 12a is held at the idle rotation opening by the biasing force of the throttle valve return spring 60. Correspondingly, the transmission return mechanism 62 holds the initial state shown in FIGS. 6 and 7A, for example.
[0060]
The relative positional relationship between the piston member 70 and the cylinder member 69 in the initial state (a) will be described in detail. The piston member 70 keeps the throttle valve 12a at the idle rotation opening. Therefore, corresponding to the length of the inner wire 75 of the throttle valve side Bowden cable 64, for example, as shown in FIG. 6 and FIG. is doing. This state of the piston member 70 is referred to as an initial state of the piston member 70.
[0061]
On the other hand, the cylinder member 69 is held in the initial state shown in FIGS. 6 and 7A with respect to the piston member 70 by the biasing force of the initial state holding compression coil spring 84, for example. At this time, the cylinder member 69 is positioned near the right end in the casing 65 as seen in FIGS. 6 and 7A, and is defined in the cylinder member 69 by the piston member 70. The first air chamber 78 has a minimum volume (zero in the illustrated example), and the second air chamber 79 has a maximum volume. This state of the cylinder member 69 is referred to as an initial state of the cylinder member 69.
[0062]
In order to start the output to the cutting blade 2 of the internal combustion engine 3 from the initial state (a) of the transmission return mechanism 62, the operator pushes the main throttle lever 14 with a two-dot chain line in FIG. When the swing operation is quickly performed to the maximum operation position P2 shown, the cylinder member 69 is simultaneously and integrally pulled to the left in FIG. 7A by the inner wire 73 of the lever-side Bowden cable 63, and For example, the transmission return mechanism 62 is in the acceleration state shown in FIG. When the cylinder member 69 shifts from the initial state (a) to the acceleration state (b), the air in the second air chamber 79 in the cylinder member 69 is caused by the action of the check valve 81. The air in the second air chamber 79 cannot flow out to the outside, and the air in the second air chamber 79 is substantially negligible from the small vent 83 formed in the piston member 70 toward the first air chamber 78. Therefore, the piston member 70 is also instantaneously forcedly moved to the left in FIG. 7 along with the cylinder member 69 due to the compressed air pressure in the second air chamber 79. I'm damned. As a result, the inner wire 75 of the throttle valve side Bowden cable 64 is pulled largely, and the throttle valve 12a is greatly opened in the fully open direction. Therefore, the acceleration performance of the internal combustion engine 3 is good, and a large output to the cutting blade 2 can be obtained instantaneously.
[0063]
However, the acceleration state in FIG. 7B is a very temporary state, and the internal state of the transmission return mechanism 62 begins to gradually shift to the set output state in FIG. 7C. That is, the piston member 70 is moved to the position of the initial state (a) via the inner wire 75 of the throttle valve side Bowden cable 64 by the biasing force of the throttle valve return spring 60. The force to return is always acting. For this reason, the compressed air in the second air chamber 79 is gradually pushed out toward the first air chamber 78 through the small vent 83 of the piston member 70. Eventually, the piston member 70 moves toward the position of the initial state (a) when the volume in the second air chamber 79 is minimized, and the other end side of the cylinder member 69 serving as a stopper. It is regulated by the end plate 74 and the compression coil spring 84 for maintaining the initial state that has been compressed, and stops. This state is the state at the time of setting output in FIG. Corresponding to the return movement of the piston member 70 from the acceleration state (b) to the set output state (c), the opening of the throttle valve 12a decreases, so that the cutting blade of the internal combustion engine 3 The output level to 2 starts to decrease from the high output level at the time of acceleration corresponding to FIG. 7B, and eventually settles to a predetermined intermediate set output level preset by the sub-throttle lever 15 by the operator. Therefore, the operator may continue the brushing operation while holding the main throttle lever 14 at the maximum operation position P2.
[0064]
FIG. 8 is a graph showing the change in the output level of the internal combustion engine 3 described above in relation to time. As shown by the solid line in the figure, according to the output control device of the present embodiment, the output level of the internal combustion engine 3 instantaneously exceeds the set output level LW during acceleration and becomes a high output level LH. Eventually, the set output level LW is settled. On the other hand, when the transmission return mechanism 62 is not provided, as shown by a broken line in FIG. 8, the output level of the internal combustion engine 3 during acceleration slowly rises from the output level LI during idling. Smoothly set output levelLWTo reach. If these are compared, the good acceleration performance by the output control device according to the present embodiment becomes clearer.
[0065]
When returning the internal combustion engine 3 to the idling state in order to stop the mowing work, the operator releases the main throttle lever 14. Then, due to the biasing force of the throttle valve return spring 60, the piston member 70 is returned to the position in the initial state (a) as the first return stage together with the cylinder member 69, and the state shown in FIG. It will be in the state shown. At the same time, as a second return step, only the cylinder member 69 is returned to the position in the initial state (a) by the biasing force of the initial state holding spring 84, and the state of the entire transmission return mechanism 62 is It returns to the initial state shown in FIG. The return operation of the cylinder member 69 from the first return stage state of FIG. 7D to the initial state of FIG. 7A is due to the increase in volume of the second air chamber 79. By the opening operation of the check valve 81 accompanying the lowering of the internal pressure and the quick exhaust action of the air in the first air chamber 78 by the large vent hole 80 of the cylinder member 69, the operation is completed instantly. Simultaneously with the return of the piston member 70 to the initial state (a), the throttle valve 12a returns to the idle rotational opening, the centrifugal clutch 5 is disconnected, and the output of the internal combustion engine 3 to the cutting blade 2 is output. Stops.
[0066]
As a modification of the first embodiment, in contrast to the first embodiment, the cylinder member 69 is connected to the throttle valve 12a side, and the piston member 70 is moved to the main throttle lever 14 side. Even if connected, the same effect can be obtained.
[0067]
The small vent 83 is not necessarily formed in the piston member 70 and does not hinder the return movement of the piston member 70 from the acceleration state (b) to the set output state (c). An appropriate position of the cylinder member 69, for example, the other end side end plate 74 of the cylinder member 69 may be drilled.
[0068]
FIGS. 9 and 10 show a transmission return mechanism 85 according to a second embodiment that exhibits the same effect as that of the first embodiment. 10 is a cross-sectional view taken along the line XX of FIG. The arrangement position of the transmission return mechanism 85 according to the second embodiment and the relationship with the throttle operation Bowden cable 11 are the same as those in the first embodiment.
[0069]
In FIG. 9, for example, a cylinder member 88 as a first member having a cylinder hole 87 with a uniform inner diameter is accommodated in a casing 86 such as a split type so that the cylinder member 88 can move by a predetermined stroke or more in its axial direction. In the cylinder hole 87, a piston member 89 as a second member that can reciprocate along the axis is fitted and inserted. The rear end portion 73a of the inner wire 73 of the lever-side Bowden cable 63 is connected to the one end side end plate 90 of the cylinder member 88, and the other end side end plate 91 of the cylinder member 88 is connected to the piston member 89. The front end portion 75a of the inner wire 75 of the throttle valve side Bowden cable 64 extending through is connected. Between the inner wire 75 of the throttle valve side Bowden cable 64 and the wire insertion hole 92 of the end plate 91 on the other end side of the cylinder member 88, airtightness between them is maintained and the inner wire is maintained. An appropriate seal member 93 that allows movement in the length direction of 75 is interposed. Further, the cylinder member 88 is closed except for the wire insertion hole 92, and the sealing member 93 keeps the airtightness in the cylinder hole 87 completely.
[0070]
The piston member 89 divides the inside of the cylinder member 88 into two air chambers (fluid chambers) 94 and 95, and the piston member 89 is moved between the piston member 89 and the cylinder member 88 by the movement of the piston member 89. The volume of the two air chambers 94 and 95 defined in the above changes. Here, the first air chamber 94 (the volume is zero in the state of FIG. 9) located on the throttle lever device 10 side is a fluid penetrating the piston member 89, as clearly shown in FIG. A large ventilation hole 96 as a passage hole and a small ventilation hole 97 as a fluid passage hole formed between the inner circumferential surface of the cylinder member 88 by forming a groove in the outer circumferential surface of the piston member 89. Through the second air chamber 95. Ventilation resistance (flow resistance) due to the large ventilation hole 96 is extremely small and sufficient to allow instantaneous relative movement of the piston member 89 or the cylinder member 88 in the direction of reducing the volume of the first air chamber 94. The amount of ventilation is guaranteed by the large ventilation hole 96. On the other hand, the ventilation resistance (flow resistance) by the small ventilation hole 97 is large, and the relative movement of the piston member 89 or the cylinder member 88 in the direction of reducing the volume of the second air chamber 95 causes the small ventilation hole 97 to move. The fluid throttle action restricts the speed to a very moderate speed.
[0071]
The piston member 89 is provided with a check valve 98 that allows only air flow from the first air chamber 94 side to the second air chamber 95 side through the large vent hole 96. For this reason, the relative movement of the piston member 89 or the cylinder member 88 in the direction of increasing the volume of the second air chamber 95 is performed quickly. On the other hand, the relative movement of the piston member 89 or the cylinder member 88 in the direction of increasing the volume of the first air chamber 94 is restricted by the large ventilation resistance of the small ventilation hole 97 and becomes extremely gradual.
[0072]
Here, the check valve 98 is formed of a circular thin plate member having an area sufficient to cover the large vent hole 96. The check valve 98 is inserted into the inner wire 75 of the throttle valve-side Bowden cable 64 and a valve stopper 99 fixed to the inner wire 75 is used to control the opening and closing of the large vent 96. It is restricted to as many strokes as necessary.
[0073]
The valve stopper 99 abuts on the other end side end plate 91 of the cylinder member 88 as a stopper, thereby reducing the volume of the second air chamber 95 or the piston member 89 or the cylinder member. The effect | action which regulates the relative moving amount of 88 is also show | played.
[0074]
Between the piston member 89 and the cylinder member 88, as a means for always exerting a biasing action so as to keep the relative position between them in the initial state shown in FIG. A coil spring 100 is interposed. The biasing force by the initial state holding compression coil spring 100 is set to be smaller than the biasing force acting on the piston member 89 by the throttle valve return spring 60.
[0075]
The operation of the transmission return mechanism 85 will be described with reference to FIG. FIG. 11 is an explanatory view showing the operation of the transmission return mechanism in a time series as in FIG. 7, and FIGS. 11 (a) to 11 (d) are (a) to (d) in FIG. It corresponds to each.
[0076]
The relative positional relationship between the piston member 89 and the cylinder member 88 in the initial state of the transmission return mechanism 85 in FIG. 11A will be described in detail. The main throttle lever 14 is in the non-operation position. Since the throttle valve 12a is held at the idle rotational opening when it is at P1, the piston member 89 corresponds to the length of the inner wire 75 of the throttle valve side Bowden cable 64, for example, As shown in FIG. 11 (a), the casing 86 is located in an approximately middle portion in the initial state as an initial state.
[0077]
On the other hand, the cylinder member 88 is held in the initial state shown in FIG. 11A with respect to the piston member 89 by the biasing force of the initial state holding compression coil spring 100, for example. At this time, the cylinder member is positioned near the right end in the casing 86 as seen in FIG. 11A, and the first piston member 89 is partitioned in the cylinder member 88. The volume of the air chamber 94 is minimal (zero in the illustrated example), and the volume of the second air chamber 95 is maximal.
[0078]
In order to start the output of the internal combustion engine 3 to the cutting blade 2 from the initial state (a) of the transmission return mechanism 85, the operator moves the main throttle lever 14 to the maximum operating position P2. When the swing operation is quickly performed, the cylinder member 88 is pulled to the left in FIG. 11A by the inner wire 73 of the lever side Bowden cable 63, and the transmission return mechanism 85 is, for example, shown in FIG. ) The acceleration state shown in When the cylinder member 88 shifts from the initial state (a) to the accelerated state (b), the large vent hole 96 is closed by the check valve 98. For this reason, the air in the second air chamber 95 in the cylinder member 88 merely moves to the first air chamber 94 side from the small vent hole 97 in a substantially negligible amount. Due to the compressed air pressure in the second air chamber 95, the piston member 89 is also forcibly moved to the left in FIG. As a result, the inner wire 75 of the throttle valve side Bowden cable 64 is pulled largely, and the throttle valve 12a is greatly opened in the fully open direction. Therefore, the acceleration performance of the internal combustion engine 3 is good, and a large output to the cutting blade 2 can be obtained instantaneously.
[0079]
However, the acceleration state in FIG. 11B is a very temporary state, and the internal state of the transmission return mechanism 85 starts to gradually shift to the set output state in FIG. That is, the piston member 89 is moved to the position of the initial state (a) via the inner wire 75 of the throttle valve side Bowden cable 64 by the biasing force of the throttle valve return spring 60. The force to return is always acting. For this reason, the compressed air in the second air chamber 95 moves little by little to the first air chamber 94 side through the small vent hole 97 of the piston member 89. Eventually, the movement of the piston member 89 toward the position of the initial state (a) is stopped by the valve stopper 99 coming into contact with the other end side end plate 91 of the cylinder member 88, and at this time, The volume in the second air chamber 95 is minimized. This state is the setting output state shown in FIG. Corresponding to the return movement of the piston member 89 from the acceleration state (b) to the set output state (c), the opening of the throttle valve 12a decreases, so that the cutting blade of the internal combustion engine 3 The output level to 2 starts to decrease from the high output level LH at the time of acceleration corresponding to FIG. 11B, and eventually reaches a predetermined intermediate set output level LW preset by the operator with the sub-throttle lever 15. Calm down. Therefore, the operator may continue the brushing operation while holding the main throttle lever 14 at the maximum operation position P2.
[0080]
When returning the internal combustion engine 3 to the idling state in order to stop the mowing work, the operator releases the main throttle lever 14. Then, due to the urging force of the throttle valve return spring 60, the piston member 89 is returned to the position in the initial state (a) as the first return stage together with the cylinder member 88, as shown in FIG. 11 (d). It will be in the state shown. At the same time, as a second return step, only the cylinder member 88 is returned to the position in the initial state (a) by the biasing force of the initial state holding compression coil spring 100, and the state of the transmission return mechanism 85 as a whole. However, it returns to the initial state of FIG. The return operation of the cylinder member 88 from the state shown in FIG. 11D to the state shown in FIG. 11A is caused by a pressure drop in the second air chamber 95 due to an increase in the volume of the second air chamber 95. The opening operation of the check valve 98 and the quick exhaust action of the air in the first air chamber 94 by the large vent 96 are completed instantly. Simultaneously with the return of the piston member 89 to the initial state (a), the throttle valve 12a returns to the idle rotation opening, the centrifugal clutch 5 is disconnected, and the output of the internal combustion engine 3 to the cutting blade 2 is output. Stops.
[0081]
According to the transmission return mechanism 85 according to the second embodiment, since there is no movement of fluid inside and outside the cylinder member 88, an appropriate liquid such as oil is sealed inside the cylinder member 88 instead of air. You can also In this way, there is an advantage that the response operability of the throttle valve 12a is further improved when the main throttle lever 14 is operated to the maximum operation position P2, and the acceleration performance is further improved.
[0082]
In the case of the transmission return mechanism 85 according to the second embodiment, as in the case of the first embodiment, as a modification, the cylinder member 88 and the piston member 89 are disposed with the directions reversed. You may set up.
[0083]
The output control device according to the present invention can be applied to various power working machines.For example, in addition to the illustrated brush cutter, when applied to a handheld or portable power working machine such as a hedge trimmer, Particularly preferred.
[0084]
In the present embodiment, the transmission return mechanism using fluid flow resistance has been described in detail, but it is needless to say that other mechanisms, electrical control means, and the like can be applied.
[Brief description of the drawings]
FIG. 1 is an overall schematic perspective view showing a brush cutter as an example of a power working machine including an output control device according to an embodiment of the present invention.
2 is an overall perspective view of the throttle lever device in FIG. 1. FIG.
FIG. 3 is an exploded perspective view of FIG. 2;
FIG. 4 is a perspective view of a main part of the throttle lever device.
5 is a partial cross-sectional view of a throttle lever device including a cross-sectional view taken along line VV in FIG.
FIG. 6 is an explanatory diagram showing an operating force transmission system between a throttle lever device and a carburetor.
FIG. 7 is an explanatory diagram showing the operation of the transmission return mechanism according to the first embodiment in time series.
FIG. 8 is a graph illustrating the change in the output level of the internal combustion engine in relation to time.
FIG. 9 is a longitudinal sectional view of a transmission return mechanism according to a second embodiment.
10 is a cross-sectional view taken along arrow XX in FIG. 9;
11 is an explanatory view showing the operation of the transmission return mechanism shown in FIG. 9 in time series.
[Explanation of symbols]
  2 Cutting blade (power work member)
  3 prime mover
  14 Main throttle lever (operating member, automatic return type operating member)
  15 Sub-throttle lever (Operation position fixed operation member)
  P2 Predetermined operation position
  62 Transmission return mechanism
  69 Cylinder member (first member)
  70 Piston member (second member)
  74 End plate on the other end of the cylinder member (stopper)
  78 First air chamber (first fluid chamber)
  79 Second air chamber (secondFluid chamber)
  80 Large ventilation holes (large fluid passage holes)
  81 Check valve
  83 Small ventilation holes (smallFluid passage hole)
  84 Compression coil spring for holding initial state (biasing means)
  85 Transmission return mechanism
  88 Cylinder member (first member)
  89 Piston member (second member)
  91 End plate on the other end of cylinder member (stopper)
  94 First air chamber (first fluid chamber)
  95 Second air chamber (secondFluid chamber)
  96 Large vent (large fluid passage hole)
  97 Small ventilation holes (smallFluid passage hole)
  98 Check valve
  100 Initial state holding compression coil spring (biasing means)
  LW setting output level
  P1 Non-operating position
  P2 Predetermined operation position

Claims (4)

Prime mover (3),
An operation member (14) for controlling the output of the motor (3) , a non-operation position (P1) and a predetermined operation position corresponding to a predetermined set output level (LW) of the motor (3) (P2), an operating member (14) having:
In response to the operation of the operating member (14) to the predetermined operating position (P2), the output of the prime mover (3) is temporarily made larger than the set output level (LW) and thereafter the prime mover (3) An output control device comprising a transmission return mechanism (62, 85) for returning the output to the set output level (LW) and holding it;
The transmission return mechanism (62, 85)
A first fluid chamber (78, 94) and a second fluid chamber (79, 95) are defined between each other, and the volume of the fluid chamber (78, 94/79, 95) is changed by moving relative to each other. A first member (69, 88) and a second member (70, 89);
The first member (69, 88) and the second member (70, 89) are disposed between the first member (69, 88) and the relative position thereof corresponding to the non-operation position (P1) of the operation member (14). Urging means (84, 100) that always act so as to keep the initial state of
Large fluid passage holes (80, 96) for relatively quickly discharging the fluid in the first fluid chamber (78, 94);
A small fluid passage hole (83, 97) for discharging the fluid in the second fluid chamber (79, 95) relatively slowly;
A check valve (81, 98) that allows fluid to flow into the second fluid chamber (79, 95) when fluid is discharged from the first fluid chamber (78, 94);
With
The first member (69, 88) is operatively connected to the operation member (14) so as to be driven simultaneously with the operation of the operation member (14) to the predetermined operation position (P2).
The second member (70, 89) is constantly urged in a direction that reduces the output of the prime mover (3), and is driven against the urging force to thereby output the prime mover (3). Operatively connected to the prime mover (3) so as to increase
The flow resistance provided by the small fluid passage hole (83, 97) corresponds to the operation of the operation member (14), and the second member (70, 88) is integrated with the first member (69, 88). 89) is set to such an extent that it is temporarily driven so as to make the output of the prime mover (3) larger than the set output level (LW),
Further, between the first member (69, 88) and the second member (70, 89), the second fluid chamber (79) extends from the second fluid passage hole (83, 97). 95), the change in the relative position of the second member (70, 89) with respect to the first member (69, 88) due to the outflow of the fluid is stopped, and the output of the prime mover (3) is reduced. An output control device comprising a stopper (74, 91) for holding at the set output level (LW). The first member is formed by one of a cylinder member (69, 88) and a piston member (70, 89) that are slidably fitted to each other, and the second member is the cylinder member (69). , 88) and a formed in the other of said piston member (70,89), the output control device according to claim 1. The operating member is automatically returned to the non-operating position where the output of the power working member (2) is cut off (P1) of the to be released from the predetermined operating position (P2) the prime mover (3) And the set output level (LW) of the prime mover (3) when the automatic return type operating member (14) is operated to the predetermined operating position (P2). The output control device according to claim 1 or 2 , comprising an operation position fixing type operation member (15) that can be adjusted. A power work machine comprising the output control device according to claim 1, 2 or 3 , and comprising a power work member (2) connected in driving to the prime mover (3).

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