EP2230395A2 - Carburettor for a combustion engine - Google Patents

Abstract

The carburetor (1) comprises a fuel supply channel (3), which is designed in a carburetor body, a throttle valve (4), and a choke valve are rotatably arranged in the fuel supply channel. A leverage is provided, which has a gas lever (7) fixed to a throttle shaft (5) and a choke lever (9) fixed to a choke shaft (8). The force of a spring loads a choke lever in the direction of an engaging plane with the gas lever.

Description

The invention relates to a carburetor for an internal combustion engine referred to in the preamble of claim 1 genus.

The DE 200 09 208 U1 describes a carburetor for an internal combustion engine of a motorized hand tool. The carburetor includes a throttle and a choke flap. To set the throttle and the choke valve in dependence on each other in several predetermined operating positions such as idle, cold start and warm start is a switch that is located directly on the carburetor and connected to the choke valve. In this case, the choke flap and the throttle flap are mechanically coupled to one another such that the switch assumes a different position in each operating position. When turning the switch a mounted on the choke shaft intermediate plate is pivoted and locked in a predetermined position with the throttle lever.

From the DE 198 53 612 A1 a carburetor for small internal combustion engines is known, comprising a throttle valve and a choke flap, wherein biasing means are provided, which the Choke the throttle valve and the choke flap in the direction of defined positions. It is provided a latching connection between the two flaps, which holds the two flaps against the biasing means in their starting positions. The latching connection can be released by a movement of the throttle valve from its starting position and has a choke lever and an associated intermediate lever, which can be brought into latching engagement with each other. The lock is released when an operator operates a throttle to accelerate the engine because it pivots the throttle lever and releases the intermediate lever.

In the known arrangements unlocking the latching is possible only when the throttle lever, in all other settings of the controls, the locking between throttle and intermediate lever is maintained.

The present invention has for its object to provide a carburetor referred to in the preamble of claim 1 genus in which an operating switch for different operating positions also includes an emergency stop position, and the emergency release the latch between the throttle lever and the Chokestellhebel is released.

This object is achieved by a gasifier with the features of claim 1.

By the invention it is achieved that the lever associated with the choke flap on the carburetor and also the choke flap itself are brought into a basic position, from the out a new actuation process can take place. If "Emergency Stop" is not activated, the triggering kinematics will not affect the throttle and choke flap lever kinematics.

According to a preferred embodiment of the invention, the Chokestellhebel is rotatably connected to the choke shaft and the spring loads the choke additionally in the direction of an open position. In this way, the number of components can be reduced. The device on the choke shaft is preferably mounted limited movable relative to the Chokestellhebel. In this way, the choke flap can be brought into its open position, although the operating switch remains in its "emergency stop" position. According to a first embodiment, it is advantageous that the device for unlocking moves the Chokestellhebel against the force of a spring axially on the choke shaft. By this movement of the Chokestellhebels, this passes into a different plane relative to the throttle lever, so that the locking is released.

According to a second embodiment of the Chokestellhebel is tiltably mounted on the choke shaft, and the device is formed by an actuating rod which generates the tilting movement. For this purpose, the Chokestellhebel is preferably mounted on a projecting through the choke shaft cross pin. In the Chokestellhebel expediently an elongated opening is provided into which one end of the choke shaft protrudes and between the contour of the opening and the end of the choke shaft is given a distance that allows a defined tilt angle. According to an advantageous embodiment, a concentric with the choke shaft arranged coil spring is provided which loads the Chokestellhebel in the direction of rotation and axial direction. In this way, the coil spring fulfills two functions, namely the return of the choke flap to its open position and the return of the Chokestellhebels.in the plane for the interaction with the throttle lever. In the first embodiment, the unlocking device suitably comprises a choke control lever which can be mechanically coupled to the choke lever. The choke control lever is fixed on the choke shaft, but freely rotatable with respect to this at least in one direction. This choke control lever comprises at least one driver, which engages in a recess of the Chokestellhebels. The driver is designed so that the choke control lever acts on the choke lever when the choke flap is to be closed.

To generate the axial movement of the Chokestellhebels it is expedient that the Chokesteuerhebel comprises at least one ramp which cooperates with the Chokestellhebel in the axial direction. It is also advantageous that two drivers are arranged on the Chokesteuerhebel, preferably diametrically relative to the choke shaft and at each of the drivers a ramp is formed. In this way, the forces can be divided evenly and jamming of the choke control lever is avoided. In order to reduce the actuating forces, it is expedient that inclined surfaces are formed on the Chokestellhebel having the same angle of inclination, as the ramps. It is also appropriate that on the Chokestellhebel a projection is provided which serves as a stop for the driver in the closing direction of the choke flap.

Fig. 1

eine perspektivische Ansicht einer ersten Aus- führungsform des Vergasers,

Fig. 2

eine Ansicht des Vergasers in Richtung auf eine Hebelanordnung für eine Drosselklappe und eine Choke- klappe in einer Stoppposition,

Fig. 3

eine vergrößerte Darstellung eines Ausschnitts des Vergasers im Wesentlichen in Richtung des Pfeiles III gemäß Fig. 2,

Fig. 4

eine Ansicht gemäß Fig. 2 mit der Hebelanordnung in Leerlaufstellung,

Fig. 5

eine Ansicht gemäß Fig. 3 in der Leerlaufstellung (in ähnlicher Perspektive),

Fig. 6

eine Ansicht gemäß Fig. 2 in einer Startposition der Hebelanordnung,

Fig. 7

eine Ansicht des Ausschnitts des Vergasers gemäß Fig. 3 in nach vorne geneigter Perspektive in der Start- position,

Fig. 8

eine Ansicht gemäß Fig. 2 in einer Chokeposition,

Fig. 9

eine Ansicht gemäß Fig. 7 in einer etwas um die Hoch- achse des Vergasers gedrehten Perspektive in der Chokeposition,

Fig. 10

eine Ansicht gemäß Fig. 2 in einer Zwischenposition der Bewegung der Hebel nach Betätigung des Bedienungsschalters in eine "Notaus-Stellung",

Fig. 11

einen Ausschnitt des Vergasers in perspektivischer Darstellung mit der Hebelanordnung in der Zwischen- position gemäß Fig. 10,

Fig. 12

eine perspektivische Ansicht einer zweiten Aus- führungsform des Vergasers,

Fig. 13

eine andere Ansicht des Vergasers in Fig. 12 mit einem Bedienungsschalter und einer Betätigungsstange,

Fig. 14

eine Darstellung gemäß Fig. 13 während der Auslöse- bewegung,

Fig. 15

eine geänderte Ansicht des Vergasers gemäß Fig. 12 in der entriegelten Position der Hebel.

An embodiment of the invention is explained below with reference to the drawing. In the drawing shows:

Fig. 1

a perspective view of a first embodiment of the carburetor,

Fig. 2

2 is a view of the carburetor in the direction of a lever arrangement for a throttle flap and a choke flap in a stop position,

Fig. 3

an enlarged view of a section of the carburetor substantially in the direction of arrow III according to Fig. 2 .

Fig. 4

a view according to Fig. 2 with the lever arrangement in idle position,

Fig. 5

a view according to Fig. 3 in idle position (in a similar perspective),

Fig. 6

a view according to Fig. 2 in a starting position of the lever arrangement,

Fig. 7

a view of the section of the carburetor according to Fig. 3 in a forward-leaning perspective in the starting position,

Fig. 8

a view according to Fig. 2 in a choke position,

Fig. 9

a view according to Fig. 7 in a perspective in the choke position, rotated slightly about the carburettor's vertical axis,

Fig. 10

a view according to Fig. 2 in an intermediate position of the movement of the levers after actuation of the operating switch in an "emergency stop position",

Fig. 11

a section of the carburetor in perspective with the lever assembly in the intermediate position according to Fig. 10 .

Fig. 12

3 is a perspective view of a second embodiment of the carburetor,

Fig. 13

another view of the carburetor in Fig. 12 with an operating switch and an operating rod,

Fig. 14

a representation according to Fig. 13 during the triggering movement,

Fig. 15

a modified view of the carburetor according to Fig. 12 in the unlocked position of the lever.

The Fig. 1 shows a carburetor 1 for an internal combustion engine, for example, in a working device, a carburetor housing 2 with a running therein mixture preparation channel 3 and a throttle valve 4 and a - in Fig. 1 invisible - includes choke flap. The throttle valve 4 is fixed to a rotatably mounted throttle shaft 5, which is provided at an end protruding from the housing 2 with an actuating lever 6 and at the other of the housing 2 projecting end with a throttle lever 7. On the actuating lever 6, a throttle linkage or a throttle cable is articulated to adjust the throttle valve 4 by turning the throttle shaft 5. This rotational movement also performs the non-rotatably mounted on the throttle shaft 5 Gasstellhebel 7.

Transverse to the mixture preparation channel 3, a choke shaft 8 is arranged in the carburetor housing 2, on which the in Fig. 1 invisible choke flap is attached. On the protruding from the carburetor housing 2 end of the choke shaft 8, a Chokestellhebel 9 is arranged, which is non-rotatably mounted on the choke shaft 8, but axially displaceable. In addition, at this end of the choke shaft 8, a choke control lever 10 is disposed which is rotatable relative to the choke shaft 8 and the choke lever 9. The choke control lever 10 has an opening 11 into which engages a control rod driven by an operating switch. The Chokesteuerhebel 10 has two parallel to the choke shaft 8 extending driver 12, which engage in recesses 13 of the Chokestellhebels 9.

In Fig. 2 the carburetor 1 is shown in a view of the lever assembly for the throttle and the choke flap in a stop position. Behind the carburetor housing 2 is on the left side of the actuating lever 6 protrudes. On the end the throttle valve shaft 5 is seated, the throttle lever 7, which comprises a parallel to a tangent of the throttle shaft 5 extending arm 14 and a right angle to the Chokestellhebel 9 bent leg 15. In this stop position, the leg 15 engages in a recess 16 at the edge of the Chokestellhebels 9. In this position of the Chokestellhebels 9 is on the right side of the carburetor housing from the mixture preparation channel outstanding Choke flap 22 in the fully open position. The Chokesteuerhebel 10 engages with its drivers 12 in the recesses 13 of the Chokestellhebels 9, and thereby lie the driver 12 at edges 28 of the Chokestellhebels 9. The positions of the throttle lever 7 and the Chokestellhebels 9 in Fig. 2 are taken due to the return springs acting on these levers. The position of the choke control lever 10 is determined by the already mentioned control rod or the operating switch of the implement.

The Fig. 3 shows an enlarged view of a section of the carburetor 1 substantially in the direction of arrow III in Fig. 2 , From the carburetor housing 2, the throttle shaft 5 protrudes, on the end of the throttle lever 7 is fixed. In addition, the protruding from the carburetor housing 2 choke shaft 8 can be seen, on which the Chokestellhebel 9 and the Chokesteuerhebel 10 are attached. Concentric with the choke shaft 8, a coil spring 17 is arranged, one end of which has a leg 18 which engages behind the throttle shaft 5 and the other end is bent to a hook 19 which is hooked to a projection 9 'of the throttle lever 9. The coil spring 17 has Thus, the function, the Chokestellhebel 9 and thus also the choke valve due to the position in which it completely opens the mixture preparation channel. In addition, the coil spring 17 acts as a compression spring, since it is supported on the one hand on the carburetor housing 2 and on the other hand on the Chokestellhebel 9 and thus presses the Chokestellhebel 9 against the Chokesteuerhebel 10.

The driver 12 on Chokesteuerhebel 10 project into the recesses 13 of the Chokestellhebels 9, wherein Fig. 3 it can be seen that the driver 12 has on one side a ramp 20 which rests against an inclined surface 27 of the edge 28. On the other hand, the driver 12 has a contour 26 extending at right angles to the choker lever 9. With this design, it is possible for the ramp 20 to slide on the inclined surface 27 in the clockwise direction of rotation of the choke control lever 10, thereby displacing the throttle lever 9 against the force of the helical spring 17 presses down, ie in the axial direction of the choke valve shaft. 8

In the direction of rotation of the choke control lever 10 counterclockwise, the driver 12 lies with its contour 26 to the projection 9 'and tows in this way the Chokestellhebel 9, whereby the choke valve is adjusted, in the sense of closing the mixture processing channel. The in Fig. 3 not visible other driver of the choke control lever 10 is also designed, this also applies to the other inclined surface 27 on the Chokestellhebel. 9

The Fig. 4 shows a view of the carburetor 1 according to Fig. 2 and the Fig. 5 shows a view according to Fig. 3 , each with the lever assembly in neutral position. This neutral position differs from that in the Figures 2 and 3 shown starting position by the changed position of the Chokesteuerhebels 10, because this is now with the contour 26 of its driver 12 at corresponding radial projections 9 ', 9 "of the Chokestellhebels 9. In the idle position, unlike the stop position, the ignition of the engine is turned on Fig. 5 it is clear that the throttle lever 7 and the Chokestellhebel 9 are in an engagement plane. It is off Fig. 4 It can be seen that on the Chokestellhebel 9 two inclined surfaces 27 are provided diametrically to the axis of rotation of the choke shaft 8. Incidentally, the reference numerals in the FIGS. 4 and 5 for equal parts with those of Figures 2 and 3 match.

The Fig. 6 shows a view of the carburetor 1 in a starting position of the lever assembly. To achieve this starting position, by means of the aforementioned control switch hinged to the operating lever 6 throttle cable and attached to the Chokesteuerhebel 10 control rod is moved so that the operating lever 6 with the throttle at a clockwise angle and the Chokesteuerhebel 10 with the Chokestellhebel 9 um an angle counterclockwise to be rotated. The movement of the gas actuating lever 7 causes the arm 14 is moved away from the Chokestellhebel 9 and the leg 15 far enough out of the recess 16 pivots out to allow rotation of the Chokestellhebels 9. The control rod moves the choke control lever 10 counterclockwise, whereby the Chokestellhebel 9 is entrained, the angle of rotation is sufficient that the leg 15 engages behind a detent 21 on the circumference of the Chokestellhebels 9 and rests against the Chokestellhebel. Then the choke flap is in the start position, ie it releases the cross section of the mixture treatment channel partially.

In Fig. 7 is a section of the carburettor 1 similar to that of Fig. 3 shows. From this illustration, the protruding from the carburetor housing 2 choke flap 22 can be seen. The leg 15 of the throttle lever 7 engages behind the locking lug 21, so that the Chokestellhebel 9 and the Chokesteuerhebel 10 are prevented from being reset by the coil spring 17 in the rest position. Incidentally, for the same parts, the reference numerals with those of Fig. 6 match.

The Fig. 8 shows a view of the carburetor 1 in a choke position of the lever assembly. In this position, the choke control lever 10 and the choke lever 9 are further rotated counterclockwise, whereby the choke flap is brought into its closed position. The throttle lever 7 remains unchanged, since the leg 15 is supported on a relative to the axis of rotation of the Chokestellhebels 9 uniform arc edge 23. The remaining reference numerals in the FIGS. 8 and 9 match for the same parts with those of the preceding figures.

In Fig. 9 a section of the carburetor is shown in the choke position of the lever assembly, wherein the curved edge 23, at the legs 15 is supported, it can be seen. In this position, the flaps in the carburetor 1, the engine can be started, wherein after starting the engine at the first actuation of the throttle lever by the operator of the throttle lever 7 is pivoted clockwise and thereby the Chokestellhebel 9 and the choke flap of the coil spring in the clockwise direction in the Be returned home position.

The Fig. 10 shows the carburetor 1 in the view of the lever assembly in an intermediate position of the lever during its movement after the operation of the control switch in the "emergency stop position". If the "emergency stop position" is set on the operating switch of the implement, while the lever arrangement on the carburettor 1 is still set in the starting position, then the actuating rod moves the choker control lever 10 in a clockwise direction. As a result, the ramps 20 of the driver 12 slide on the inclined surfaces 27 of the Chokestellhebels 9 (see. Fig. 3 ), which has the consequence that the Chokestellhebel 9 is moved in the axial direction of the choke shaft 8 against the force of the coil spring 17. The drivers are then based on the surface of the Chokestellhebels 9, as in Fig. 11 is shown. This axial displacement of the Chokestellhebels 9 is sufficient to bring the Chokestellhebel 9 in a plane below the throttle lever 7 and thus cancel the locking of the leg 15 to the locking lug 21, as from Fig. 11 is apparent. The coil spring 17 ensures that the Chokestellhebel 9 and the choke flap are moved back to the normal position. Since then the leg 15 again in the region of the recess 16 and the driver 12 in the region of Recesses 13 are located, the Chokestellhebel 9 is pressed by the coil spring 17 in the axial direction of the choke shaft 8 against the Chokesteuerhebel 10.

The Fig. 12 shows a second embodiment of a carburetor 31 having a housing 32 with a mixture-processing channel 33 extending therein and a throttle valve 34 and a - Fig. 12 invisible - includes choke flap. The throttle valve is fixed to a rotatably mounted throttle shaft 35, which is provided at an end protruding from the housing 32 with a gas lever 36. Transversely to the mixture preparation channel 33, a choke flap shaft is arranged in the carburetor housing 32, from the in Fig. 12 only one end 37 can be seen. On the choke valve shaft a Chokestellhebel 38 is arranged, which is in the representation in Fig. 12 in an engagement plane with the throttle lever 36 is located. For fixing the Chokestellhebels 38 on the choke shaft is a transverse pin 45, on which the Chokestellhebel 38 is pivotally mounted about the axis of the transverse pin 45.

Between the housing 32 and the Chokestellhebel 38, a coil spring 39 is concentrically provided on the choke shaft, which serves both to restore the choke flap in its fully open position and the Chokestellhebel loaded in the direction of the engagement plane. In the Chokestellhebel 38 is an elongated opening 40, in which the end 37 of the choke shaft protrudes, which is designed with respect to the cross section such that only in the longitudinal direction of the opening 40 and thus orthogonal to the longitudinal axis the transverse pin 45, a relative movement is possible. The position of throttle lever 36 and Chokestellhebel 38 in Fig. 12 corresponds to the in Fig. 6 shown starting position.

In Fig. 13 is the carburetor 31 according to Fig. 12 shown in another view, wherein additionally a control switch 41 and an actuating rod 42 are shown. The operating rod 42 is connected at one end 42 'to the operating switch 41, and another end 42 "is suspended in a corresponding receptacle 43 on the choke lever 38. Depending on the position set by the operating switch 41, the choking lever 38 is also adjusted, for example in Figs in Fig. 12 shown starting position. The throttle lever 36 mounted on the throttle shaft 35 and the choke lever 38 mounted on a choke shaft 44 are in the engagement plane in which cooperation of the levers is provided. The Chokestellhebel 38 is fixed by means of the transverse pin 45 to the choke shaft 44, wherein the coil spring 39 presses the Chokestellhebel 38 in the engagement plane. Out Fig. 13 is also located in the mixture processing channel 33 choke flap 46 can be seen.

When the operating switch 41 is moved to the "emergency stop position", this results in a movement of the operating rod such that the end 42 "presses on the choke lever 38. Since the point of introduction of force lies outside the axis of the transverse pin 45 the Chokestellhebel 38 is pivoted about this axis and the gas adjusting lever 36 facing the end 38 'of the Chokestellhebels 38 lowered against the force of the coil spring 39 Fig. 14 is a position during the geschilderten expiration of unlocking shown. Incidentally, for the same parts, the reference numerals with those of Figures 12 and 13 match.

The Fig. 15 shows a modified view of the carburetor 31 according to Fig. 12 In the unlocked state of throttle lever 36 and Chokestellhebel 38. In this case, the Chokestellhebel 38 is pivoted about the axis of the transverse pin 45, so that the end 38 'of the Chokestellhebels 38 is lowered below the lower edge of the throttle lever 36 and thus the mutual engagement is canceled. The coil spring 39 then returns the choke lever 38 and the choke flap 46 to the home position in which the choke flap 46 fully opens the mixture processing channel 33. In addition, the coil spring 39 presses the side of the Chokestellhebels 38, on which the end 38 'is up, so that the Chokestellhebel 38 is again in the engagement plane. Incidentally, for the same parts, the reference numerals with those of FIGS. 12 to 14 match.

Claims (14)

Carburettor (1) for an internal combustion engine with a mixture preparation channel (3) formed in a carburettor housing (2), in which a throttle valve (4) and a choke flap (22) are rotatably arranged and with a lever arrangement which is mounted on a throttle shaft (5). fixed throttle lever (7) and one on a choke shaft (8) fixed Chokestellhebel (9), wherein the throttle valve (4) and the choke flap (22) are adjustable in a plurality of operating positions and the lever assembly assumes corresponding positions, characterized in that a device for unlocking between the throttle lever (7) and the Chokestellhebel (9) is provided in an emergency stop operation and a spring (17) is present, the force of the Chokestellhebel (9, 38) in the direction of an engagement plane with the throttle lever (7, 36 ) charged. Carburettor according to claim 1,
characterized in that the Chokestellhebel (9) rotatably connected to the choke shaft (8) and the spring (17, 39) additionally loads the choke flap (22) in the direction of an open position. Carburetor according to claim 1 or 2,
characterized in that the device is mounted on the choke shaft relative to the Chokestellhebel (9) limited movable. Carburettor according to one of claims 1 to 3,
characterized in that the device for unlocking the Chokestellhebel (9) against the force of the spring (17) axially on the choke shaft (8) shifts. Carburettor according to one of claims 1 to 3,
characterized in that the Chokestellhebel (38) is tiltably mounted on the choke shaft (8) and the device is formed by an actuating rod (42) which generates the tilting movement. Carburettor according to claim 5,
characterized in that in the choke shaft (8) a transverse pin (45) is fixed, on which the Chokestellhebel (38) is tiltably mounted. Carburetor according to claim 6,
characterized in that in the Chokestellhebel (38) an opening is provided into which one end of the choke shaft (8) protrudes and between the contour of the opening and the end (37) of the choke shaft (8) is given a distance which defines a Tilt angle allows. Carburettor according to one of claims 1 to 7,
characterized in that a concentric with the choke shaft (8) arranged coil spring (17) is provided which loads the Chokestellhebel (9) in the direction of rotation and axial direction. Carburetor according to claim 3,
characterized in that the device comprises a Chokesteuerhebel (10) which is mechanically coupled to the Chokestellhebel (9). Carburetor according to claim 9,
characterized in that the Chokesteuerhebel (10) comprises at least one driver (12) which engages in a recess (13) of the Chokestellhebels (9). Carburettor according to one of claims 9 or 10,
characterized in that the choke control lever (10) comprises at least one ramp (20) cooperating with the choke lever (9) in the axial direction. Carburettor according to claim 11,
characterized in that two drivers (12) on the Chokesteuerhebel (10) are arranged and at each of the drivers (12) has a ramp (20) is formed. Carburettor according to claim 12,
characterized in that on the Chokestellhebel (9) inclined surfaces (27) are formed, which have the same inclination angle as the ramps (20). Carburettor according to one of claims 10 to 13,
characterized in that on the Chokestellhebel (9) at least one projection (9 ', 9') is provided which serves as a stop for the driver (12) in the closing direction of the choke flap (22).

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