EP3181296B1 - Gas-fixing tool with a combustion chamber - Google Patents

Description

TECHNICAL AREA

The invention relates to a gas fastening tool with a combustion chamber or pre-combustion, such as for example a nailer.

STATE OF THE ART

The state of the art includes the document US 3,820,359 A which describes a fixing tool.

The invention relates to sealing or fixing tools, said gas, that is to say, the tools comprising an internal combustion engine operating by firing a combustion air mixture in a combustion chamber, the fuel being injected into the chamber by an injection device from a fuel container called a gas cartridge. Such tools are intended to drive fasteners in support materials to attach parts. Gas nailers are now widespread. As fuel for an internal combustion engine, there may be mentioned for example gasoline, alcohol, in liquid form and / or gas.

In general, such a tool is portable and comprises a housing in which is mounted the propulsion internal combustion engine of a driving piston of a fastener. Such a tool may also include a battery power supply and a handle, handling and shooting on which is mounted a detent actuating the tool.

A firing cycle includes several steps such as dispensing a quantity of fuel through the cartridge, admitting the fuel into the chamber, mixing the fuel with air in the chamber, igniting and combusting the fuel. mixing for driving the piston, and evacuation of combustion gases from the chamber.

A combustion chamber comprises at least one gas intake or exhaust valve. This valve comprises a body movable between a first closed position and a second open position of a gas intake or discharge orifice.

The valves used in the present art have disadvantages. Indeed, their configurations lead to significant pressure drops during the admission or evacuation of gas, which lengthen the duration of the firing cycle. For example, a valve is known whose moving body has an elongated shape along an axis and comprises gas passage orifices oriented radially with respect to this axis. The gas must pass radially through these radial orifices and then move longitudinally along the axis. This baffled path generates the above-mentioned head losses and tends to slow down the firing cycle of the tool.

The present invention provides a problem solution, which is simple, effective and economical.

SUMMARY OF THE INVENTION

The invention thus proposes a gas fastening tool, comprising an internal combustion engine with a piston and a combustion or pre-combustion chamber, this chamber comprising at least one valve, such as an intake or evacuation valve. of gas, said valve comprising a body movable between a first closed position and a second open position, characterized in that said body has an elongated tubular shape and comprises an internal bore opening at both longitudinal ends of said body to form respectively two orifices for longitudinal passage of gas.

In the present application, the term pre-combustion chamber, a chamber in which is intended to take place a precombustion of an air-fuel mixture, before the injection of this mixture into a combustion chamber to complete the combustion of the mixture.

According to the invention, the movable body of the valve is "hollow", that is to say that its internal bore is opening at both longitudinal ends of the body. The body thus comprises two axial or longitudinal orifices which allow the gas to circulate substantially in a straight line, and thus without a baffle. This makes it possible to limit the pressure losses during the admission or the evacuation of gas in the chamber, and thus optimize the duration of the firing cycle of the tool.

• ledit corps a une forme générale cylindrique,
• ledit corps porte à sa périphérie externe au moins un joint d'étanchéité,
• ledit au moins un joint d'étanchéité s'étend dans un plan transversal passant sensiblement par un des deux orifices précités,
• ledit corps est monté mobile en translation longitudinale dans un carter, formé de préférence par un assemblage de pièces ou d'éléments,
• ledit carter comprend un premier élément cylindrique tubulaire de forme allongée dans laquelle est logé et peut coulisser ledit corps,
• ledit carter comprend un second élément cylindrique configuré pour être engagé dans ledit corps lorsque ce dernier est en position de fermeture,
• ledit second élément porte à sa périphérie externe au moins un joint d'étanchéité configuré pour coopérer avec ledit corps, ledit au moins un joint d'étanchéité s'étendant de préférence dans un plan transversal passant sensiblement par un des deux orifices précités,
• ledit second élément comprend un rebord annulaire externe et est entouré par un ressort de rappel prenant appui respectivement sur ledit rebord et sur ledit corps, afin de solliciter ce dernier dans sa position d'ouverture,
• ledit carter comprend un troisième élément comportant un alésage interne dans lequel ledit corps est destiné à coulisser, ledit troisième élément comportant au moins un orifice de passage de gaz débouchant dans cet alésage et orienté sensiblement radialement par rapport à l'axe longitudinal dudit corps, cet orifice étant configuré pour être obturé par ledit corps lorsqu'il est dans sa position de fermeture et laissé libre lorsqu'il est dans sa position d'ouverture,
• ledit corps est relié par un organe de forme allongée à un clapet et/ou à un autre corps mobile de vanne,
• ledit corps est relié à une tige rectiligne s'étendant le long de l'axe longitudinal dudit corps et présentant un diamètre externe inférieur au diamètre interne de l'alésage dudit corps,
• ladite tige est reliée par des jambes à une des extrémités longitudinales dudit corps,
• ledit corps est relié soit à un fourreau présentant un diamètre interne sensiblement identique au diamètre interne de l'alésage dudit corps, soit à une ou plusieurs tiges rectilignes s'étendant sur une circonférence de diamètre sensiblement identique à celui dudit corps.

The chamber may comprise one or more of the following features, taken separately from each other or in combination with each other:

• said body has a generally cylindrical shape,
• said body carries at its outer periphery at least one seal,
• said at least one seal extends in a transverse plane passing substantially through one of said two orifices,
• said body is movably mounted in longitudinal translation in a housing, preferably formed by an assembly of parts or elements,
• said casing comprises a first tubular cylindrical element of elongated shape in which said body is housed and can slide,
• said casing comprises a second cylindrical element configured to be engaged in said body when said body is in the closed position,
• said second member carries at its outer periphery at least one seal configured to cooperate with said body, said at least one seal extending preferably in a transverse plane passing substantially through one of said two orifices,
• said second element comprises an outer annular flange and is surrounded by a return spring bearing respectively on said flange and on said body, in order to urge said body in its open position,
• said casing comprises a third element comprising an internal bore in which said body is intended to slide, said third element comprising at least one gas passage opening opening into said bore and oriented substantially radially with respect to the longitudinal axis of said body, this orifice being configured to be closed by said body when in its closed position and left free when in its open position,
• said body is connected by an elongate member to a valve and / or other movable valve body,
• said body is connected to a rectilinear rod extending along the longitudinal axis of said body and having an outer diameter smaller than the internal diameter of the bore of said body,
• said rod is connected by legs to one of the longitudinal ends of said body,
• said body is connected either to a sleeve having an inner diameter substantially identical to the internal diameter of the bore of said body, or to one or more straight rods extending over a circumference of diameter substantially identical to that of said body.

BRIEF DESCRIPTION OF THE FIGURES

• la figure 1 est une vue schématique partielle en coupe axiale d'une chambre de combustion d'un outil de fixation à gaz, selon l'invention, cette chambre comportant une vanne dont le corps mobile est en position d'ouverture ;
• la figure 2 est une vue correspondant à la figure 1 et dans laquelle le corps mobile est en position de fermeture ;
• la figure 3 est une autre vue schématique partielle en coupe axiale de la chambre de combustion de la figure 1 ;
• la figure 4 est une vue correspondant à la figure 1 et illustre une variante de réalisation de l'invention.

The invention will be better understood and other details, characteristics and advantages of the present invention will appear more clearly on reading the description which follows, given by way of non-limiting example and with reference to the accompanying drawings, in which:

• the figure 1 is a partial schematic view in axial section of a combustion chamber of a gas fastening tool, according to the invention, this chamber comprising a valve whose movable body is in the open position;
• the figure 2 is a view corresponding to the figure 1 and wherein the movable body is in the closed position;
• the figure 3 is another partial schematic view in axial section of the combustion chamber of the figure 1 ;
• the figure 4 is a view corresponding to the figure 1 and illustrates an alternative embodiment of the invention.

DETAILED DESCRIPTION

The attachment tool 10 is partially visible in the drawings. This tool comprises a housing 12 in which there is an internal combustion engine with a combustion chamber 14 (or a pre-combustion chamber and a combustion chamber) intended to contain a mixture of air and fuel whose firing causes the propulsion of a piston intended to drive a fastener extracted from a feed magazine, the fastener being intended to be anchored in a support material, at the exit of a guide-tip extending at the front of the case. All these components of gas fastening tools are well known to those skilled in the art and therefore they have not all been represented in the drawings.

The fuel supply to the combustion chamber 14 of the engine is effected, via an injection member, from a fuel gas cartridge.

The housing 12 of the tool comprises a handle 16 for gripping and handling the tool. The handle 16 is also used for firing, by an actuation trigger 18 mounted on it.

In the example shown, the combustion chamber 14 comprises a valve 20 for admitting the fuel gas delivered by the cartridge. This valve 20 is hollow or more exactly its movable body 22 is hollow.

The movable body 22 is movable between an open position of an inlet orifice 24, shown in FIG. figure 1 , and a closed position of the inlet orifice 24, shown in FIG. figure 2 .

The movable body 22 is movable in a fixed housing 26 of the combustion chamber, which is here formed by an assembly of parts or elements which will be described in detail in the following.

The body 22 has an elongate tubular shape and comprises an internal bore 28 opening at the two longitudinal ends 22a, 22b of the body to form respectively two orifices 30a, 30b of longitudinal passage of gas.

The body 22 has a generally cylindrical shape in the example shown. It comprises an outer cylindrical surface and has a substantially constant outer diameter. It comprises at its end 22a an external annular groove in which is mounted a seal 30 intended to cooperate with the housing 26. It further comprises, substantially in the middle, an outer annular groove 31 in which is intended to be engaged one end of a finger 34 actuated by the trigger 18.

The end 22a of the body includes an inner annular flange defining the orifice 30a, which is a gas outlet. The end 22b of the body includes an inner annular flange defining the orifice 30b, which is a gas inlet. These flanges have substantially the same internal diameter.

Although this is in no way limiting, the bore 28 of the body has a restriction 33 of its passage section substantially in the middle of the body. This restriction 33 defines an internal diameter substantially equal to that of the aforementioned flanges.

The restriction 33 and the groove 31 are substantially located in the same plane P1 transverse to the longitudinal axis X of the movable body 22. The seal 30 is located in another transverse plane P2 passing substantially through the orifice 30a of the body 22.

The housing 26 of the chamber comprises a tubular cylindrical element 32 in which is housed and can slide the body 22. This element 32 has an elongated shape with a longitudinal axis X.

The element 32 comprises an inner cylindrical surface cooperating with the seal 30 carried by the body 22.

In the example shown, the element 32 comprises a radial orifice (relative to the X axis) which can be traversed by one end of an ignition plug 36 to initiate the combustion of the air-fuel mixture in the bedroom. This candle 36 may be of the piezoelectric type and be actuated by the aforementioned finger 34 during the intervention of a user on the trigger 18.

The member 32 further includes a through radial lumen 38 which has an elongated shape along the X axis. The finger 34 includes an end that passes through the lumen 38 and is engaged in the groove 31 of the body. Upon actuation of the trigger 18, the finger 34 is moved in translation along the axis X, and its end slides in the light to drive the movable body 22 in the casing 26 of the chamber. It is thus understood that the length of the light (dimension along the X axis) depends on the expected stroke of displacement of the body 22. Advantageously and as is visible in the drawings, regardless of the position of the body 22 along of the axis, the light 38 is covered and thus closed by the body 22.

The casing 26 comprises another element 40 mounted at one longitudinal end of the element 32. This other element 40 comprises an internal bore 42 communicating with the internal housing of the element 32.

The bore 42 has a generally cylindrical shape of axis X of revolution and is therefore coaxial with the inner housing of the element 32. This bore 42 preferably has an internal diameter substantially equal to the internal diameter of the inner housing.

The body 22 of the valve is able to slide in the bore 42.

The element 40 comprises a radial orifice opening into the bore 42 and forming the aforementioned inlet 24. This orifice 24 communicates with the aforementioned injection member for fueling the combustion chamber.

As can be seen in the drawings, when the body 22 is in its open position ( figure 1 ), the orifice 24 is left free, which allows the fuel to enter the bore 42 and then to cross longitudinally the body 22 (see arrows). When the body 22 is in its closed position ( figure 2 ), the orifice 24 is hermetically sealed by the body 22.

It is thus understood that the displacement path of the body, between its two extreme positions, is greater than the diameter of the orifice 24, so that the body does not interfere with the passage of gas through the orifice 24. opening position (here high position) and that the body completely closes the orifice in the closed position (here low position).

The housing 26 further comprises another element 46 of generally cylindrical shape aligned on the axis X. This element 46 is disposed at one end of the chamber and is intended to be partially housed in the bore of the body 22, when last is in the closed position ( figure 2 ).

This element 46 comprises at its outer periphery an outer annular groove housing a seal 48 intended to cooperate with the rim of the end 30b of the body 22. The seal 48 is located in another transverse plane P3.

The element 46 comprises at its longitudinal end opposite the body 22 an outer annular flange 50 whose outer diameter is here substantially identical to that of the body 22. A return spring 44, here helical, is mounted around the element 46 and comprises a first end bearing on the flange 50 and an opposite end bearing on the end 30b of the body to urge it into its open position.

As can be seen in the drawings, element 46 may include an internal axial bore 52 for passage of a spark plug (not shown) in place of the aforementioned one. The bore 52 is here aligned on the X axis.

The end 30a of the body is connected to a cylindrical rod 54 of longitudinal axis X. This rod 54 has a diameter smaller than the internal diameter of the body. Its diameter is preferably between 0.1 and 0.3 times the internal diameter of the body, and is for example 0.15-0.16 times the internal diameter of the body.

The rod 54 has a length significantly greater than that of the body 22 and extends into the element 32 of the housing 26. Its longitudinal end located on the body side is connected to the end 30a of the body by two or three legs 56 , or more. These legs 56 are regularly distributed around the X axis and are therefore diametrically opposed when there are two of them. The legs 56 are intended to be traversed by the gas and are preferably profiled to limit the loss of load in operation (arrows).

As can be seen in figure 3 , the end of the rod 54 opposite the body may be connected to a valve 58 and / or to another valve 60, such as a discharge valve.

The valve 58 comprises for example a disk 62 traversed by the rod 54 and integral therewith. The disc 62 is intended to cooperate with an annular seat 64 of the element 32 of the housing. The figure 3 illustrates the valve 58 in the open position, the disk 62 being away from its seat. This case corresponds to the opening or upper position of the body 22 ( figure 1 ). In the closed or low position of the body 22, the disc 62 co-operates with the seat 64 to seal. The seat 64 can define a gas passage orifice from the combustion chamber 14, which is a pre-combustion chamber, to another chamber of combustion 66.

In the example shown, the valve 60 comprises a movable body 68 in the form of a disk or piston carrying at its outer periphery a seal 70 intended to cooperate with an internal cylindrical surface of a discharge orifice 72 combustion chamber combustion chamber 66.

It is important to note that this valve 60 could be equipped with a movable body similar to that 22 of the other valve.

The attachment tool 10 and the combustion chamber 14, 66 can operate as follows. In general, placing one end of the tool on the support material in which a fastener is to be placed releases a quantity of fuel from the cartridge, which is conveyed from the cartridge to the orifice of the cartridge. intake 24 of the element 40. The fuel enters the pre-combustion chamber 14 because the opening of the valve (movable body 22 in the up position or opening - figure 2 ). The user generally benefits from a duration of a few seconds, before the fuel is diffused into the atmosphere, to actuate the trigger 18. When the trigger 18 is actuated, the finger 34 is moved. which will cause both the displacement of the body 22 from its open position to its closed position, as well as the generation of a spark by the spark plug 36. This spark causes the precombustion of the air-fuel mixture in the combustion chamber 14, which causes an increase in pressure in the chamber 14, that is to say inside the element 32. When this pressure exceeds a certain threshold, the valve 58 opens and allows the mixture to pass into the combustion chamber, the pressure of which increases. Shortly thereafter, the flame in turn passes the valve 58 and ignites the combustion chamber 66 and causes the displacement of the piston and the ejection of a fastener in the support material. After the return of the piston to its rest position, the valve 60 opens to expel the combustion gases through the discharge orifice 72.

The figure 4 illustrates an alternative embodiment of the invention in which the rod 54 is replaced by a sleeve 54 'having an internal diameter substantially identical to the internal diameter of the bore 28 of the body 22, or rectilinear rods extending over a circumference of diameter substantially identical to that of the body.

Claims (14)

1. Gas fixing tool (10) comprising an internal combustion engine with a piston and a combustion or precombustion chamber (14), this chamber comprising at least one valve (20) such as a gas intake or exhaust valve, said valve comprising a body (22) able to move between a closed first position and an open second position, characterized in that the said body has a tubular elongate shape and comprises an internal bore (28) open at the two longitudinal ends (22a, 22b) of the said body to respectively form two longitudinal gas passage orifices (30a, 30b).
2. Tool (10) according to Claim 1, in which the said body (22) has a cylindrical overall shape.
3. Tool (10) according to Claim 1 or 2, in which the said body (22) at its external periphery bears at least one seal (30).
4. Tool (10) according to the preceding claim, in which the said at least one seal (30) extends in a transverse plane (P2) passing substantially through one (30a) of the two aforementioned orifices.
5. Tool (10) according to one of the preceding claims, in which the said body (22) is mounted with the ability to move in longitudinal translation in a casing (26) preferably made up of an assembly of parts or of elements (32, 40, 46).
6. Tool (10) according to the preceding claim, in which the said casing (26) comprises a first tubular cylindrical element (32) of elongate shape in which the said body (22) is housed and can slide.
7. Tool (10) according to Claim 5 or 6, in which the said casing (26) comprises a second cylindrical element (46) configured to be engaged in the said body (22) when the latter is in the closed position.
8. Tool (10) according to the preceding claim, in which the said second element (46) at its external periphery bears at least one seal (48) configured to collaborate with the said body (22), the said at least one seal preferably extending in a transverse plane (P3) passing substantially through one (30b) of the two aforementioned orifices.
9. Tool (10) according to Claim 7 or 8, in which the said second element (46) comprises an external annular rim (50) and is surrounded by a return spring (44) bearing respectively against the said rim and against the said body (22) so as to urge the latter into its open position.
10. Tool (10) according to one of Claims 5 to 9, in which the said casing (26) comprises a third element (40) comprising an internal bore (42) in which the said body (22) is intended to slide, the said third element comprising at least one gas passage orifice (24) opening into this bore and oriented substantially radially with respect to the longitudinal axis (X) of the said body, this orifice being configured to be shut off by the said body when it is in its closed position and left uncovered when it is in its open position.
11. Tool (10) according to one of the preceding claims, in which the said body (22) is connected by a member (54) of elongate shape to a valve shutter (58) and/or another mobile body (68) of the valve (60).
12. Tool (10) according to one of the preceding claims, in which the said body (22) is connected to a rectilinear rod (54) extending along the longitudinal axis (X) of the said body (22) and having an outside diameter smaller than the inside diameter of the bore (28) of the said body (22).
13. Tool (10) according to the preceding claim, in which the said rod (54) is connected by legs (56) to one of the longitudinal ends (22a) of the said body (22).
14. Tool (10) according to one of Claims 1 to 11, in which the said body (22) is connected either to a sleeve that has an inside diameter substantially identical to the inside diameter of the bore of the said body, or to one or more rectilinear rods extending on a circumference of a diameter substantially equal to that of the said body.

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