Title of Invention

THROTTLE OPERATING DEVICE

Technical Field

[0001]

The present invention relates to a throttle operating device that is applied to a work machine such as a brush cutter which transmits power from an engine via a power transmission shaft in an external tubular pipe to a blade of the brush cutter to perform mowing of grass, cutting of branches or the like, and contributes to a reduction in size of a structure near a throttle lever which adjusts an output of the engine.

Background Art

[0002]

Conventionally, in a shoulder- carried, back-carried or the like portable brush cutter, a throttle operating device is provided which adjusts the output of the engine that drives the blade.

The throttle operating device has a configuration that includes an external tubular pipe, an operation box which includes a throttle lever adjusting the output of the engine and a safety lever, and an operation grip which covers the external tubular pipe and is gripped by an operator.

A transmission mechanism in the external tubular pipe has a power transmission shaft that transmits the power from the engine located at a proximal end side thereof to the blade located at a tip side thereof. Furthermore, the operation grip is gripped by an operator.

[0003]

Moreover, in the throttle operating device having the configuration as mentioned above, an operation of the throttle lever is effective on the condition that an operator pulls the safety lever (grasps the operation grip), and the operation of the throttle lever is transmitted to a throttle valve of the engine through a throttle wire.

As a mechanism that adjusts the throttle of the engine through such a throttle wire, for example, Patent Documents 1 to 7 are known.

Citation List

Patent Document

[0004]

[Patent Document 1] United

[Patent Document 2] United

[Patent Document 3] UUnniitteedd States Patent No. 2480083

[Patent Document 4] UUnniitteedd States Patent No. 4633724

[Patent Document 5] UUnniitteedd States Patent No. 6223622 Bl

[Patent Document 6] UUnniitteedd States Patent No. 3472096

[Patent Document 7] UUnniitteedd States Patent No. 2602179

Summary of Invention

Technical Problem

[0005]

However, in the throttle operating device mentioned above, generally, the operation box and the operation grip are placed in the external tubular pipe in series. such an arrangement, in order for an operator to be able to operate the throttle lever and the safety lever with one hand while gripping the operation grip, it is desirable to place the operation box as close as possible to the operation grip.

[0006]

The present invention was made in view of the above circumstances, and an object thereof is to provide a throttle operating device of satisfactory operability that reduces the size of a structure near a throttle lever that adjusts the output of an engine, and is able to easily operate the throttle lever or the safety lever when an operator grips the operation grip.

Solution to Problem

[0007]

In order to achieve the above object, a throttle operating device of the present invention includes an external tubular pipe that accommodates a transmission mechanism which transmits the output from an engine; an operation box that is connected to the external tubular pipe and includes a throttle lever which adjusts the output of the engine, and a safety lever which makes the operation of the throttle lever effective or ineffective; an operation grip that is provided so as to cover the external tubular pipe and is gripped by an operator; wherein an end portion of the operation grip which is extended and which is overwrapped by the operation box, and the operation box and the operation grip are connected to each other in the end portion of the operation grip which is extended and overwrapped by the operation box.

Advantageous Effects of Invention

[0008] In the structure in which the operation box including the throttle lever and the safety lever and the operation grip are placed adjacent on the external tubular pipe, the end portion of the operation grip is extended and overwrapped by the operation box, and the operation box and the operation grip are connected to each other in the end portion of the operation grip which is extended and overwrapped by the operation box. Thus, the throttle lever and the safety lever included in the operation box, and the operation grip are placed adjacent to each other without being separated from each other like the conventional art. As a result, a structure near the throttle lever can be downsized, and it is possible to operate the safety lever and the throttle lever without difficulty when an operator grips the operation grip, whereby it is possible to realize a throttle operating device with satisfactory operability.

Brief Description of Drawings

[0009]

FIG. 1 is a perspective view that shows a portable brush cutter 1 (a work machine) according to an embodiment of the present invention.

FIG. 2 is a perspective view of a state in which a part of a casing 21 of an operation box 20 is notched in order to show a connection state of the operation box 20 and an operation grip 50 according to a first embodiment of the present invention.

FIG. 3 is a side view in which FIG. 2 is viewed laterally.

FIG. 4 is a cross-sectional view in which the operation box 20 is cut along an axis A.

FIG. 5 is a perspective view of a state in which a part of a casing 21 of an operation box 20 is notched in order to show a connection state of the operation box 20 and an operation grip 50 according to a second embodiment of the present invention. FiG. 6 is a side view in which FIG. 5 is viewed laterally.

Description of Embodiments

[0010]

(First Embodiment)

A first embodiment of the present invention will be described with reference to drawings FIGS. 1 to 4. FIG. 1 is a schematic diagram that shows a portable brush cutter 1 that is applied to the present invention.

As shown in FIG. 1 , the portable brush cutter 1 includes a power portion 4 that has an air-cooled engine 3 provided in a device main body 2, an external tubular pipe 5 that is extended forward from the power portion 4, and a cutter device 6 that is provided in a front end of the external tubular pipe 5.

[0011]

Moreover, the power of the engine 3 is transmitted to the cutter device 6 via a crankshaft (not shown) of the engine 3, a clutch (not shown), and a power transmission shaft 7 accommodated in the external tubular pipe 5, thereby rotating a movable blade 8 provided in the cutter device 6.

Furthermore, the external tubular pipe 5 is provided with an operation handle 9 for defining the operation direction of the portable brush cutter 1, an operation grip 50, and an operation box 20 for adjusting the output of the engine 3.

Furthermore, the portable brush cutter 1 is provided with a shoulder strap 10 for carrying the device main body 2.

[0012]

Next, a throttle operating device 100, which is constituted by the operation box 20 and an operation grip 50 connected to the operation box 20, will be described with reference to FIGS. 2 to 4.

The operation box 20 has a casing 21, and a throttle lever 22 and a safety lever 23 that are provided in the casing 21. The throttle lever 22 and the safety lever 23 are operated by an operator. The external tubular pipe 5 is placed so as to pass through holes 21 A and 21 B formed front and rear side of the casing 21.

The casing 21 of the operation box 20 has a half-division structure and is joined and integrated via a bolt (not shown).

[0013]

Furthermore, the throttle lever 22 is connected to an operation shaft of the engine 3 via a crank member (24) described later and a throttle wire (not shown) connected to the crank member (24).

Furthermore, the safety lever 23 is provided in a position that is separated by a predetermined distance outward in a radial direction of the operation grip 50 from the operation grip 50 so as to be easily operated by an operator.

[0014]

In addition, the present example is set so that, when the throttle lever 22 is rotated in a clockwise direction (an arrow bl direction) in FIG. 3, the throttle is opened to increase the output of the engine 3, and when the throttle lever 22 is rotated in a counterclockwise direction (an arrow al direction) in FIG. 3, the throttle is narrowed to decrease the output of the engine 3. Furthermore, the throttle lever 22 is biased in the counterclockwise direction (the arrow al direction) by a coil spring (29) described blow and is configured so that the throttle is narrowed.

[0015]

Furthermore, as shown in FIGS. 2 and 3, an operation grip 50 gripped by an operator is connected to the inner portion of the casing 21 of the operation box 20. The operation grip 50 is placed so as to cover the outer peripheral surface of the external tubular pipe 5. The operation grip 50 has an aluminum pipe 51 and a gripping portion 52. The aluminum pipe 51 is made such that one of the operation grip 50 is extended (the portion is called an extension portion 51 A) and protruded to the inner portion of the casing 21 via the through hole 21B of the casing 21 of the operation box 20. The gripping portion 52 is made of rubber and is placed so as to cover the outer peripheral surface of the aluminum pipe 51.

Moreover, by such a configuration, the extension portion 51 A of the aluminum pipe 51 that is extended and protruded into the casing 21 is overwrapped by a part of the casing 21 of the operation box 20.

[0016]

A first fastening member 54 is provided on a distal end side of the operation grip 50. The first fastening member 54 is inserted through a first fastening hole (not shown) which penetrates a laterally protruded plate portion 90 of the gripping portion 52 as shown in FIG. 2 and a laterally protruded plate portion of the aluminum pipe 51 (not shown). When the first fastening member 54 is fastened, a diameter of the aluminum pipe 51 is reduced so that the aluminum pipe 51 is fixed to the external tubular pipe 5. Accordingly, by fastening the first fastening member 54, the gripping portion 52 and the aluminum pipe 51 are fixed to the external tubular pipe 5. Therefore, the operation grip 50 is fixed to the external tubular pipe 5.

A second fastening member 64 is provided on a distal end side of the operation grip 50 so as to be adjacent to the first fastening member 54 as shown in FIG. 2. The second fastening member 64 is inserted through a second fastening hole (not shown) which penetrates the gripping portion 52 and the aluminum pipe 51. By fastening the second fastening member 64, the gripping portion 52 is fixed to the aluminum pipe 51. Accordingly, the gripping portion 52 does not dislocate relative to the aluminum pipe 51.

[0017]

A flange 53 (a first protrusion portion) is provided in a tip ortion of the aluminum pipe 51 which is located at the inner portion of the casing 21. The flange 53 is protruded from the outer peripheral surface of the aluminum pipe 51 outward in a radial direction of the aluminum pipe 51 (a radial direction of the external tubular pipe 5). The flange 53 is engaged with an inner side of an edge portion of the through hole 21 B in the casing 21, thereby connecting the aluminum pipe 51 to the casing 21 of the operation box 20. According to the engagement of the flange 53 with the inner side of an edge portion of the through hole 21 B in the casing 21 , the relative movement between the aluminum pipe 51 and the casing 21 of the operation box 20 are restricted in an axial direction of the external tubular pipe 5. Furthermore, the flange 53 is provided with square protrusions 71, 72 on the outer peripheral surface of the flange 53 so as to protrude from the outer peripheral surface of the flange 53 outward in the radial direction of the aluminum pipe 51. FIG. 2 shows two square protrusions 71 , 72 which are provided on the opposite side of the outer peripheral surface of the flange 53. Since the square protrusions 71, 72 engage with concave portions (not shown) formed inside the casing 21, the relative movement between the aluminum pipe 51 and the casing 21 of the operation box 20 are restricted in a circumferential direction of the external tubular pipe 5.

[0018]

The operation box 20 to be connected to the operation grip 50 will be described. As shown in FIGS. 2 to 4, the throttle lever 22 is integrally connected to the crank member 24 by a fastener (not shown) such as a bolt and a nut. The crank member 24 is supported by the casing 21 around a shaft body 25, which is perpendicular to the axis A, in a freely rotating manner.

As shown in FIG. 4, a gear 27 is provided around a rotation shaft 26 formed integrally with the crank member 24 in a freely rotating manner. Between the gear 27 and the crank member 24, a disc spring 28 is provided. The disc spring 28 slides over a side surface of the gear 27 so that the crank member 24 rotates relative to the gear 27 when an engaging member 31 (described later) locks the gear.

Furthermore, a coil spring 29 for biasing the crank member 24 in the counterclockwise direction (the arrow al direction) in FIG. 3 is provided between a periphery of the rotation shaft 26 which is integral with the crank member 24 and the casing 21.

In addition, frictional force of the disc spring 28 to the gear 27 is set to be greater than the rotational biasing force of the crank member 24 by the coil spring 29.

[0019]

The safety lever 23 is supported by the casing 21 around the rotation shaft 23 A in a freely rotating manner, and a pair of engaging members 30 and 31 is fixed to a proximal end portion thereof. Furthermore, a coil spring 32 for biasing the safety lever 23 in the clockwise direction (an arrow b2 direction) in FIG. 3 is provided between the rotation shaft 23 A of the safety lever 23 and the casing 21.

Since the crank member 24 is biased in the counterclockwise direction (an arrow a2 direction) when the safety lever 23 is not operated, a first engaging member 30 of the safety lever 23 is engaged with a step portion 24A of the crank member 24.

Accordingly, the throttle lever 22 is prevented from being operated. Furthermore, when the safety lever 23 is operated and is rotated in the counterclockwise direction (the arrow a2 direction) in FIG. 3, the first engaging member 30 releases the engagement with the step portion 24A of the crank member 24, and allows the operation (the movement in the clockwise direction (the arrow bl direction) in FIG. 3) of the throttle lever 22.

[0020]

A second engaging member 31 of the safety lever 23 is separated from teeth of the gear 27 when the safety lever 23 is not operated. Moreover, in this state, since the first engaging member 30 is in the state of being engaged with the crank member 24, the operator is not able to operate the throttle lever 22.

Furthermore, when the safety lever 23 is operated and the second engaging member 31 is rotated in the counterclockwise direction (the arrow a2 direction) in FIG. 3, the safety lever 23 is engaged with one of the teeth of the gear 27 to restrict the rotation of the gear 27. At this time, since the first engaging member 30 is in the state in which the engagement with the step portion 24 A of the crank member 24 is released, the crank member 24 can be rotated around the shaft body 25. However, the crank member 24 is connected to the gear 27 via the disc spring 28, and the frictional force of the disc spring 28 to the gear 27 is set to be greater than the rotational biasing force (the biasing force in the counterclockwise direction (the arrow al direction)) of the crank member 24 by the coil spring 29. Thus, unless an operator operates the throttle lever 22, the crank member 24 is not rotated around the shaft body 25.

Moreover, when an operator rotates the throttle lever 22 in the clockwise direction, the crank member 24 rotates around the shaft body 25 in the clockwise direction (the arrow bl direction) in FIG. 3. At this time, the crank member 24 slides relative to the gear 27 via the disc spring 28. Thereafter, even if an operator separates his/her finger from the throttle lever 22, the throttle lever 22 is maintained in the operation position by the frictional force between the disc spring 28 and the gear 27. As a consequence, the output of the engine 3 is kept constant.

[0021] To summarize the above points,

(1) In the state of FIG. 3 in which an operator does not operate the safety lever 23, the first engaging member 30 of the safety lever 23 is engaged with the step portion 24A of the crank member 24 biased in the counterclockwise direction (the arrow al direction), fixes the crank member 24, and prevents the throttle lever 22 from being operated. As a result, when an operator does not operate the safety lever 23, the throttle of the engine 3 is prevented from left open. Therefore, the cutter device 6 is not operated, and safety is maintained.

[0022]

(2) When an operator operates the safety lever 23 in the arrow a2 direction, the engagement of the first engaging member 30 with the step portion 24A of the crank member 24 is released. As a result, it is possible to operate the throttle lever 22 around the shaft body 25 in the clockwise direction (the arrow bl direction) in FIG. 3.

Accordingly, it is possible to perform the throttle operation of the engine 3 with the throttle lever 22, and the cutter device 6 can be driven.

[0023]

At the same time, by the rotation of the safety lever 23 in the counterclockwise direction (the arrow a2 direction), the second engaging member 31 shown in FIG. 3 is engaged with one of the teeth of the gear 27 to lock the gear 27 and restrict the rotation thereof. At this time, the gear 27 is connected to the crank member 24 via the disc spring 28, but the frictional force of the disc spring 28 to the gear 27 is set to be greater than the rotational biasing force (the biasing force in the counterclockwise direction (the arrow al direction)) of the crank member 24 by the coil spring 29. Thus, as long as the throttle lever 23 is not operated (even if a worker operates the safety lever 23), the crank member 24 is not rotated. Moreover, when, as mentioned above, an operator operates the throttle lever 22, the crank member 24 slides relative to the gear 27 via the disc spring 28, and then, even if an operator separates his/her finger from the throttle lever 22, the throttle lever 22 is maintained in the operation position after the rotation by the factional force between the disc spring 28 and the gear 27. As a consequence, the output of the engine 3 is kept constant, which makes it possible for the cutter device 6 to perform smooth lawn mowing and mowing work.

[0024]

Moreover, in a case where the operation by the cutter device 6 is finished, when an operator separates his/her hand from the throttle lever 22 and the safety lever 23, the safety lever 23 is rotated in the clockwise direction (the arrow b2 direction) by the biasing force due to the coil spring 32, and the pair of engaging members 30 and 31 is also rotated in the same direction.

At this time, since the second engaging member 31 is separated from the gear 27 to release the lock of the gear 27, the throttle lever 22 and the crank member 24 are forcibly rotated in the counter clockwise direction (the arrow al direction) narrowing the throttle of the engine 3 by the biasing force of the coil spring 29. When the first engaging member 30 is engaged with the step portion 24A of the crank member 24 in this state, the crank member 24 is fixed in the position shown in FIG. 3.

[0025]

As described in detail as above, according to the throttle operating device 100 of the portable brush cutter 1 described in the first embodiment, in a structure in which the operation box 20 including the throttle lever 22 and the safety lever 23 and the operation grip 50 are placed adjacent on the external tubular pipe 5, the end portion of the operation grip 50 is extended and protruded to be overwrapped by the operation box 20, and the operation box 20 and the operation grip 50 are connected to each other in the end portion of the operation grip 50 which is extended and overwrapped by the operation box 20.

Furthermore _; since the flange 53 and square protrusions 71, 72 are respectively engaged with the inner side of an edge portion of the through hole 21 B in the casing 21 and the concave portions (not shown) formed inside the casing 21, the casing 21 of the operation box 20 is connected to the aluminum pipe 51 of the operation grip 50 in the end portion of the operation grip 50 which is extended and overwrapped by the operation box 20 with the relative movement between the aluminum pipe 51 and the casing 21 of the operation box 20 in an axial and circumferential direction of the external tubular pipe 5 being restricted. As a result, the throttle lever 22 and the safety lever 23 included in the operation box 20 are placed adjacent to the operation grip 50. As a consequence, the size of the structure near the throttle lever 22 can be reduced, and an operator is able to operate the throttle lever 22 without difficulty when the operator grips the operation grip 50, whereby it is possible to realize a satisfactory throttle operation. Since the operation grip 50 is fixed to the external tubular pipe 5 by the first fastening member 54, the operation grip 50 is prevented from being moved along and around the axis A of the external tubular pipe 5. As a consequence, it is possible to hold the operation box 20 with respect to the operation grip 50 in a stable state. Since the gripping portion 52 is fixed to the aluminum pipe 51 by the second fastening member 64, the gripping portion 52 is prevented from falling off of the aluminum pipe 51. As a consequence, it is possible to maintain the operation grip 50 in a stable state.

[0026]

(Second Embodiment)

A second embodiment of the present invention will be described with reference to FIGS. 5 and 6. In this embodiment, members common to the members used in the first embodiment are designated by the same reference numerals, and a description thereof is omitted.

The second embodiment is different from the first embodiment in the connection structure between the operation box 20 and the operation grip 50 in the throttle operating device 100.

[0027]

Specifically, in a connection structure shown in FIGS. 5 and 6, where the operation box 20 including the throttle lever 22 and the safety lever 23, and the operation grip 52 are placed adjacent on the external tubular pipe 5, the end portion of the aluminum pipe 51 of the operation grip 50 is extended and protruded (indicated as the extension portion 51 A) and overwrapped by the casing 21 of the operation box 20.

Furthermore, in the second embodiment, the flange 53 is omitted which was provided in the extension portion 51 A of the aluminum pipe 51 in the first embodiment.

[0028]

In the overlapped location of the end portion of the aluminum pipe 51, a connection band 60 is wound around the outer peripheral surface of the extension portion 51A of the aluminum pipe 51. The connection band 60 is configured so that the respective end portions thereof are protruded outward in the radial direction of the aluminum pipe 51. The protrusion portions (reference numeral 60 A) overlap with each other, and the overlapped portion of the protrusion portions 60A is fastened by a fastener 62. The fastener 62 includes a fastening bolt 61 and a nut (not shown). Here, the operation grip 50 is fixed to the external tubular pipe 5 by fastening the fastener 62 of the connection band 60.

[0029] The connection band 60 is placed so as to protrude from the outer peripheral surface of the aluminum pipe 51 outward in the radial direction of the aluminum pipe 51. The protruded location is engaged with an inner side of an edge portion of the through hole 21 B in the casing 21, whereby the aluminum pipe 51 does not escape from the casing 21 of the operation box 20. Accordingly, the relative movement between the aluminum pipe 51 and the casing 21 is restricted in the axial direction of the external tubular pipe 5.

Furthermore, two square plates 81, 82 are provided on the opposite side of the outer peripheral surface of the extension portion 51 A so as to protrude from the outer peripheral surface of the extension portion 51 A outward in a radial direction of the aluminum pipe 51 (a radial direction of the external tubular pipe 5) as shown in FIGS. 5 and 6. Here, only the square plate 82 is visible in FIGS. 5 and 6. Since the square plates 81, 82 engage with concave portions (not shown) formed inside the casing 21, the relative movement between the aluminum pipe 51 and the casing 21 are restricted in a circumferential direction of the external tubular pipe 5.

[0030]

As described in detail as above, according to the throttle operating device 100 of the portable brush cutter 1 described in the second embodiment, the operation box 20 including the throttle lever 22 and the safety lever 23 and the operation grip 50 are placed adjacent on the external tubular pipe 5. Furthermore, in the end portion of the operation grip 50 which is extended and overwrapped by the operation box 20 where the end portion of the operation grip 50 is extended and protruded to be overwrapped by the operation box 20, the operation box 20 and the operation grip 50 are connected to each other by the connection band 60 fastened by the fastener 62. Thus, the throttle lever 22 and the safety lever 23 included in the operation box 20 are placed adjacent to the operation grip 50. As a result, the size of the structure near the throttle lever 22 can be reduced, and an operator is able to operate the throttle lever 22 without difficulty when the operator grips the operation grip 50, whereby it is possible to realize a satisfactory throttle operation.

[0031]

Furthermore, in the throttle operating device 100 of the portable brush cutter 1 of the second embodiment, the protrusion portion 60A of the connection band 60 and the fastener 62 which fastens the protrusion portion 60A are fitted into the concave portion 21 C formed inside the casing 21 of the operation box 20. Accordingly, the operation grip 50 is prevented from coming out of the operation box 20, by means of the protrusion portion 60A and the fastener 62 fitting into the concave portion 21 C. Since the square plates 81, 82 engage with concave portions (not shown) formed inside the casing 21, the relative movement between the aluminum pipe 51 and the casing 21 are restricted in a circumferential direction of the external tubular pipe 5. Since the operation grip 50 is fixed to the external tubular pipe 5 by the connection band 60 fastened by the fastener 62, the operation grip 50 is prevented from being moved along and around the axis A of the external tubular pipe 5. As a consequence, it is possible to hold the operation box 20 with respect to the operation grip 50 in a stable state.

[0032]

Furthermore, the throttle operating device 100 mentioned above is applied to the portable brush cutter 1, but may also be applied to a small power work machine such as a power generator in which the output of the engine 3 is adjusted by the operation box 20 without being limited thereto, and the application scope thereof is not limited.

[0033]

As mentioned above, the embodiments of the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to the embodiments, and a design modification or the like of the scope not departing from the gist of the present invention is also included.

Industrial Applicability

The present invention relates to a throttle operating device that is applied to a work machine such as a brush cutter which transmits power from an engine via a power transmission shaft in an external tubular pipe to a blade of the brush cutter to perform mowing of grass, cutting of branches or the like, and contributes to a reduction in size of a structure near the throttle lever which adjusts the output of the engine.

Reference Signs List

[0034]

1 portable bush cutter (work machine)

3 engine

5 external tubular pipe

20 operation box

21 casing

22 throttle lever

23 safety lever

50 operation grip

51 aluminum pipe

51 A extension portion

53 flange (first protrusion portion)

54 fastening bolt (fastening portion)

60 connection band A protrusion portion (second protrusion portion) fastener

0 throttle operating device