GB2384526A

GB2384526A - Carburettor for cutting implements

Info

Publication number: GB2384526A
Application number: GB0201982A
Authority: GB
Inventors: Mario Possamai
Original assignee: ALPINA SpA
Current assignee: ALPINA SpA
Priority date: 2000-12-29
Filing date: 2002-01-29
Publication date: 2003-07-30
Anticipated expiration: 2022-01-29
Also published as: FR2819018A3; DE20120005U1; ES1050820Y; ES1050820U; GB0201982D0; GB2384526B; ITVE20000027U1; FR2819018B3

Abstract

A carburettor for implements, in particular trimmers and bush cutters using cutting line comprises a venturi diffuser 2 at its inlet with a manually-operated shutter operated by lever 8 providing a choke setting for engine starting. A fuel delivery tube 22 is provided with a spray nozzle 20 disposed in the diffuser, and its other end is disposed in the tank 24. The tube 22 has an internal annular rib (28) for supporting a ball (30), providing a non-return ball valve in the fuel delivery tube 22.

Description

CARBURETTOR FOR IMPLEMENTS, IN PARTICULAR TRIMMERS AND BUSH CUTTERS USING CUTTING LINE This invention relates to a carburettor for implements, in particular trimmers and bush cutters using cutting line.

Carburettors for forming the air and fuel mixture for feeding controlledignition engines are known.

These known carburettors generally comprise a main jet, an idling jet, an auxiliary jet, and throttle valves for operation during starting and acceleration.

An aim of the invention is to provide a fixed capacity carburettor which is of simple construction and easy manoeuvrability.

Accordingly, the present invention provides a carburettor for implements, in particular trimmers and bush cutters using cutting line, comprising a venturi diffuser provided at its inlet end with a manuallyoperated shutter, and a tube provided with a spray nozzle disposed in the diffuser and having its other end disposed in a tank, the tube being internally provided with an annular rib for supporting a ball formed of a material of specific gravity greater than that of the liquid feeding the carburettor.

The invention is described in detail hereinafter with reference to the accompanying drawings, in which: Figure 1 is a side view of a carburettor according to the invention, Figure 2 is a front view thereof in its starting configuration, and Figure 3 shows it in the same view as Figure 2, in the configuration in which the engine is operating at normal working speed.

As can be seen from the figures, the carburettor of the invention comprises substantially a venturi diffuser 2 provided externally with cooling

fins 4, at its inlet end 6 there being provided a lever 8 for operating a shutter

10.

The shutter consists of a plate hinged to the carburettor body on a pin 12 and movable between two end positions, in one of which it faces a small hole 14 at the end 6 of the diffuser 2 and in the other of which it presents to said end a hole 16 having the same dimensions as said end.

In a position downstream of the throat of the diffuser 2 (the term "downstream" referring to the direction of advancement of the mixture) there is inserted a tube 18 provided with a spray nozzle 20 housed in the actual diffuser 2.

The other end of the tube is sealedly engaged in a pipe 22 partly inserted into a petroJ or mixture tank 24.

In the pipe 22 there is inserted a bush 26 with its annular edge 28 flared to support a ball 30 formed of a material of specific gravity greater than that of the petrol or mixture.

The carburettor of the invention operates in the following manner : for engine ignition the lever 8 is positioned in the configuration shown in Figure 2 so that the air passes through the diffuser only via the hole 14. In this manner the air flow within the diffuser 2 creates during its passage through the throat a vacuum which draws the mixture or petrol from the tank 24 along the pipe 22, the mixture being enriched as it is mixed only with little air.

When the engine has started, the user rotates the lever ô in the direction which presents the hole 16 to the end of the diffuser 2, so increasing the air quantity and hence feeding a technically valid mixture to the engine.

At the moment in which feed to the engine is interrupted, the ball 30 falls by gravity to rest on the bush 26 and prevent the mixture located within the pipe 22 from returning to the tank.

From the foregoing it is clear that the carburettor of the invention has numerous advantages and in particular is of extremely simple construction while at the same time being easy to manoeuvre.

Claims

CLAIMS 1. A carburettor for implements, in particular trimmers and bush cutters using cutting line, comprising a venturi diffuser provided at its inlet end with a manually-operated shutter, and a tube provided with a spray nozzle disposed in the diffuser and having its other end disposed in a tank, the tube being internally provided with an annular rib for supporting a ball formed of a material of specific gravity greater than that of the liquid feeding the carburettor.
2. A carburettor as claimed in claim 1, wherein the shutter comprises a plate including two holes of different dimensions which are selectively presentable to the inlet opening of the diffuser.
3. A carburettor as claimed in claim 1, wherein the diffuser is provided externally with cooling fins.
4. A carburettor for implements, in particular trimmers and bush cutters using cutting line, substantially as hereinbefore described with reference to the accompanying drawings.