DE60316551T2 - Powered and user-worn tool equipped with an internal combustion engine - Google Patents

Abstract

The motor is the type fueled with gasoline mixture and synthetic oil for application in powered tools whose weight when operating is borne by the user whereby the sparking plug (1b) is the type with incandescent filament, the powering current of the plug (1b) is delivered only in the motor starting phase, and the compression ratio is such as to ensure that the temperature of the sparking plug filament (1b) at the end of an explosion reaches a value so high as to preserve the incandescence of the filament until the next explosion. <IMAGE>

Description

The The present invention relates to a powered and a user worn tool equipped with a gasoline internal combustion engine is and the improved properties in terms of cost, weight and dimensions, and in terms of reduction and simplification of the Has components.

General state of the art

Tools are known which are equipped with an endothermic engine which is ignited by means of a spark plug and operated with a gasoline-synthetic oil mixture and whose weight is carried by the user during use, such as garden tools, brush cutters, blowers , Atomizers, hedge trimmers, chainsaws and so on. An endothermic engine for such hand tools is in EP-A-0 631 040 disclosed. Such tools have desirable characteristics of ease of handling, reduced weight and dimensions, and low cost of ownership. A brief description of such a tool will be described below with reference to FIGS 1 and 2 given.

It Model airplane engines are also known with a spark plug with filament are equipped and only work with mixtures of methyl alcohol (and synthetic or castor oil) included in which the candle filament by supplying battery DC for the entire duration of the engine operation or kept glowing during the starting phase becomes.

The font US-A-3 435 404 discloses a glow plug connector that can be removably attached to a glow plug that is mounted in a generic model airplane engine to connect the glow plug of the engine to a battery during the engine startup phase. In the description of the prior art, the document mentions a model airplane engine that uses gasoline as fuel.

The font EP-A-0 485 676 addresses the problem of eliminating some complications (spark timing, boost coils, capacitors, break points) in spark ignition in gasoline powered gasoline engines and solves the problem by replacing the spark ignition with a glow plug glow using a glow plug housed in a special ignition chamber , which is separate from the combustion chamber, with a timing pre-chamber zone in which a catalyst is exposed.

Objects of the invention

Of the general purpose of the present invention is the realization a powered and user-worn tool, which is equipped with a gasoline engine and the improved properties in terms of weight and dimensions, in terms of reduction and simplification of components as well with regard to the reduction of acquisition, operating and maintenance costs having.

Brief description of the invention

The powered and user-carried tool according to the present invention is equipped with an internal combustion engine operated with a gasoline synthetic oil mixture having a combustion chamber (FIG. 1c ) and an ignition means ( 1b ), which is exposed in the combustion chamber, and is characterized in that:

• - the ignition means an incandescent candle is
• - of the Activation current of the filament candle only in the starting phase of the engine is supplied, and
• - the compression ratio of the engine so chosen is that guaranteed is that the temperature of the filament of the filament at the end of a filament Combustion rate reaches a value that is so high that the glow spiral to the next Combustion cycle is maintained.

drawings

The Features and advantages of the present invention are achieved by the following description explains with reference to the appended Drawings is given, which is an example of a brushcutter with a conventional one Illustrate engine. In particular, the FIGURES show the following:

1 is an overall perspective view of a conventional brushcutter, and

2 is an exploded view of some components of the same brushcutter.

Description of the invention

• – ein Gehäuse "a" zum Unterbringen eines Zweitaktmotors (1) und seiner Komponenten, wie zum Beispiel des Schwungrades, der Zündspule und so weiter,
• – ein Tank "b" für das Gemisch,
• – ein Bediengriff "c",
• – eine röhrenförmige Stange "d" zum Unterbringen der Kraftübertragungswelle,
• – ein Haltebügel "e",
• – einen Fadenkopf "f".

1 shows an overall perspective view of a conventional brushcutter. Its essential components are the following:

• A housing "a" for accommodating a two-stroke engine ( 1 ) and its components, such as the flywheel, the ignition coil and so on,
• A tank "b" for the mixture,
• A control handle "c",
• A tubular rod "d" for housing the power transmission shaft,
• - a headband "e",
• - a thread head "f".

• 1. ein Zylinder mit Kühlrippen 1a, eine Zündkerze 1b und eine innenliegende zylindrische Kammer 1c;
• 2. ein Kolben;
• 3. eine Pleuelstange, eine Kurbel und eine Antriebswelle;
• 4. ein Schwungrad, das auf der Antriebswellenabtriebsseite befestigt ist, bestehend aus einem Gebläse 4a und zylindrischen Segmenten 4b, die an einem Ende an Stiften des Gebläses angelenkt sind und in der Lage sind, bei laufendem Motor eine Kupplungsverbindung mit einem zylindrischen Becher 4c herzustellen, in dem sie montiert sind und der mit der Treibwelle 4d verkeilt ist, welche die Bewegung zu dem Fadenkopf überträgt;
• 5. ein Kasten, der nahe dem Schwungrad 4 montiert ist, zum Aufnehmen der Zündkerzenzündspule 1b; und
• 6. eine mechanische Vorrichtung zum manuellen Anlassen, wobei das Anlassen durch Ziehen eines Startseils 6a erfolgt.

2 shows an exploded view of the engine, which is housed in the housing "a", and some of its components. In particular, the following parts are shown:

• 1. a cylinder with cooling fins 1a , a spark plug 1b and an internal cylindrical chamber 1c ;
• 2. a piston;
• 3. a connecting rod, a crank and a drive shaft;
• 4. a flywheel, which is mounted on the drive shaft output side, consisting of a fan 4a and cylindrical segments 4b , which are articulated at one end to pins of the blower and are able, with the engine running, a coupling connection with a cylindrical cup 4c in which they are mounted and that with the drive shaft 4d is wedged, which transmits the movement to the thread head;
• 5. a box near the flywheel 4 is mounted, for receiving the spark plug ignition coil 1b ; and
• 6. a mechanical device for manual starting, wherein the starting by pulling a starter cable 6a he follows.

The structure of the flywheel 4 is quite expensive and complicated because it is made of die-cast aluminum and the blower 4a also includes permanent magnets intended to generate a rotating magnetic field to produce a (in 2 not shown) to energize the induction coil of the power generator, which feeds the ignition coil.

in the Following is the innovative solution discussed which the present invention compared to the illustrated above conventional Represents internal combustion engine.

The The idea underlying the present invention is that the ignition of the engine with a filament bulb of the type used in model aircraft engines from, for example, the O.S. type F brand with anomalous feed method compared to the conventional one Method of operating the engine with a filament plug to considerable To realize advantages.

For one Correct operation of the engines with filament candles will normally Mixtures not with gasoline but with methyl alcohol.

But the innovation of the present invention requires operation of the engine with a mixture of gasoline and a power supply to the spark plug coil only during the starting phase of the engine, because the helix after the starting phase of the engine kept permanently glowing by a suitable choice of the compression ratio becomes.

The suitable choice of the compression ratio to a permanent glow of the spark plug coil can be reached by gradually increasing the ratio compared to conventional Values until the temperature of the coil at the end of a combustion cycle reaches a value high enough that the glow up to the next Combustion cycle is maintained.

If we take the example of a well-known two-stroke brush cutter engine with a displacement of 30.5 ^cm3 and a compression ratio of 7.5, so it should be noted that if the relatively conventional spark plug is replaced with a candle with incandescent filament, such as Type F of the OS brand is sufficient to increase the compression ratio to 12.3, while, for example, a bulge is formed on the piston crown to achieve a permanent glow of the spark plug coil, even without it being supplied with power.

• – Die Verwendung einer Zündkerze mit Glühwendel ermöglicht den Verzicht auf die Zündspule und die Realisierung eines weniger komplizierten und leichteren Schwungrades ohne Dauermagneten und die Verwendung preisgünstigerer Materialien als Gussaluminium, weil es nur Kühlfunktionen und den Schwungradeffekt erbringen muss.
• – Bei Tests, die mit einem bekannten Motorsensenmotor durchgeführt wurden, der gemäß der vorliegenden Erfindung modifiziert wurde, wurde überraschend festgestellt, dass bei gleicher Leistung die Möglichkeit einer Senkung des Kraftstoffverbrauchs um mehr als 30% besteht, mit dem Vorteil sowohl geringerer Betriebskosten als auch einer geringeren Schadstoffemission.
• – Der Wegfall der Dauermagneten in dem Schwungrad führt zu einem geringeren Kraftaufwand beim Ziehen des Startseils, nicht nur wegen der geringeren Masse des Schwungrades, sondern auch, weil das rotierende Magnetfeld der Induktionsspule und das induzierte Magnetfeld und der Widerstand gegen das Drehen des induzierten Magnetfeldes wegfallen. Außerdem gestattet die verringerte Masse des Schwungrades und das Fehlen des besagten Widerstandes weniger Motorleistung bei gleicher Drehzahl. Der Wegfall von Magnetfeldern vermeidet auch die Gefahr von durch sie verursachten Interferenzen und Störungen von in der Nähe befindlichen elektronischen Geräten.
• – Der Wegfall der Zündspule und die Möglichkeit des Realisierens eines weniger komplexen und preisgünstigeren Schwungrades bedeutet nicht nur eine Senkung der Motorproduktions- und -unterhaltskosten, sondern auch weniger Gewicht und kleinere Abmessungen des Motors mit einer daraus resultierenden besseren Handlichkeit, Beweglichkeit und einer besseren Benutzerfreundlichkeit des Werkzeugs, in dem der Motor installiert ist. Außerdem ermöglicht die Vereinfachung des Zündsystems das Anlassen und Betreiben des Motors in der einen oder der anderen der beiden möglichen Drehrichtungen der Antriebswelle.
• – Dass die Zündkerze nur während der Motorstartphase mit Strom beaufschlagt wird, erlaubt die Verwendung von Aktivierungsbatterien, die, während eine lange Lebensdauer gewährleistet ist, kleiner und leichter sind, wie zum Beispiel zwei handelsübliche Taschenlampenbatterien mit 1,5 V vom Typ AA.

An internal combustion engine according to the innovative solution described above has considerable advantages:

• - The use of a spark plug with filament allows dispensing with the ignition coil and the realization of a less complicated and lighter flywheel without permanent magnets and the use of less expensive materials than cast aluminum, because it only has to provide cooling functions and the flywheel effect.
• It has surprisingly been found in tests carried out with a known brushcutter motor modified according to the present invention that with the same power there is the possibility of a reduction of the fuel consumption by more than 30%, with the advantage of both lower operating costs and one lower pollutant emission.
• - The elimination of the permanent magnets in the flywheel leads to less force when pulling the starter cable, not only because of the lower mass of the flywheel, but also because the rotating magnetic field of the induction coil and the induced magnetic field and the resistance to the rotation of the induced magnetic field omitted , In addition, the reduced mass of the flywheel and the absence of said resistance allows less engine power at the same speed. The elimination of magnetic fields also avoids the risk of interference and interference caused by them from nearby electronic devices.
• - The elimination of the ignition coil and the possibility of realizing a less complex and less expensive flywheel means not only a reduction in engine production and maintenance costs, but also less weight and smaller dimensions of the engine with a resulting better manageability, flexibility and ease of use of the Tool in which the engine is installed. In addition, the simplification of the ignition system allows the starting and running of the engine in one or the other of the two possible directions of rotation of the drive shaft.
• The fact that the spark plug is energized only during the engine starting phase allows the use of activating batteries, which are smaller and lighter while providing long life, such as two standard AA 1.5V flashlight batteries.

The Means that can be used to supply power to the spark plug only during To accomplish the starting phase, all you need is one Switch to exist in the circuit of the filament is used and by a control button, which is located on the handle of the power tool is in a closed state can be offset: a button that the user during the entire start phase pressed must hold.

One Shutting down the engine can also be accomplished by: you attach a control on the handle, which serves to fuel the supply to interrupt the engine.

As can be addressed above the batteries that can be used to operate the spark plug, commercially available flashlight batteries which can either be disposed of or are rechargeable. In view of this latter possibility, an embodiment of the powered tool include a charging device for the batteries, to make it easier for the user to recharge.

It it is understood that in the embodiments described above numerous modifications, adaptations, variants and substitutions of elements by other functionally equivalent elements can be without departing from the scope of the following claims.

So could for example, operating the spark plug only during the engine start phase be accomplished by means of a switch, which is not actuated by a key is, but by a timer when pulling the starter cord works automatically.

Claims (5)

Powered and user-worn tool equipped with an internal combustion engine operated with a gasoline synthetic oil mixture and a combustion chamber ( 1c ) and an ignition means ( 1b ) in the combustion chamber ( 1c ), characterized in that: - the ignition means ( 1b ) is an incandescent filament, - the activation current of the filament is supplied only in the starting phase of the engine, and - the compression ratio of the motor is selected so as to ensure that the temperature of the filament of the filament at the end of a combustion cycle reaches a value, the so high is that the annealing of the helix is maintained until the next combustion stroke. Powered and worn by a user tool according to claim 1, characterized in that the means for Accomplishing the activation limited to the starting phase of the engine the filament candle is used, consists of a switch operating in the circuit the filament candle added is and with the help of a control key, which the user during the entire engine start phase pressed must be able to be put into a closed state. Powered and worn by a user tool according to claim 1, characterized in that the switching off of the Motors is accomplished by means of a manual control element, the designed for it is to interrupt the fuel supply to the engine. Powered and worn by a user tool according to claim 1, characterized in that the stream, the Glow filament candle activated, supplied by Penlight batteries of the disposable or rechargeable type becomes. Powered and worn by a user tool according to claim 4, characterized in that it is a device to recharge the batteries.