DE2913557A1 - SOUND REDUCER FOR A COMBUSTION-ACTUATED FASTENING TOOL - Google Patents

Description

ELISABETH JUNG dr.phuγ-ipl-chem.

J ü H \ A Π NSCKIRDEV / AHN dr. here. has., dipl-phys.

GERHARD S CH M ITT- N I LS O N dr.-ing.

GERHARD 8. HAGEN dr.phil.

PETER HfRSCH dipl-ing.

PATENT LAWYERS

8000 MÖNCHEN 40, P.O. BOX40 1468 CLEMENSSTRASSE 30 TELEPHONE: (089) 34 50 TELEGRAM / CABLE: INVENT MUNICH TELEX: 5-29 686

April 4th 1979

Q 063 M + a (Dr.SchN / hm / ba)

Olin Corporation

New Haven, Connecticut 06511, V.St.A.

"Sound reducing valve for an internal combustion engine Fastening tool "

Claimed priority:

April 5, 1978, Australia, registration no. PD 3914/78

The invention relates to a Brennkraftbetatigt.es tool according to Preamble of claim 1.

The invention also relates to internal combustion operated, i. Propellant-operated tools of the type used for driving of fasteners !! or the like. into a solid base or support,

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for example wood, concrete or metal can be used. In particular The invention relates to tools with a piston that is used to drive in the fastener as a function from the detonation of an explosive charge.

Tools of the aforementioned type were due to excessive Noise generated by detonation of the explosive charge is deemed to be faulty or disadvantageous. In in some cases the noise or noise is close to the pain threshold. Attempts to eliminate this problem ^ were unsuccessful for various reasons. A major difficulty arises because of the conflicting requirements the noise suppression and the requirement of a clearance or space at the combustion zone to one to avoid adverse accumulation or residue. As for the last point, the essential thing is the structure or the accumulation of combustion by-products (residue) between the functional surface of the tool Avoid as this will lead to clogging or blockage of the tool and for the user can be life-threatening. If the free space between functional surfaces is increased to reduce the risk of Verr. Keeping stoofens as low as possible naturally follows that that noise suppression will also be a minimum. This means the relatively large amount of free space lets eäu large volume of combustion gas with high

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Pressure from the tool in an instant, so that an extremely loud noise is generated.

From US Pat. No. 3,743,048, a special construction is known which aims to suppress noise reach. In this construction, a sliding sleeve is provided around the tool barrel, around a To form a chamber into which the combustion gas can escape. The theory is that venting or venting the Gas over a relatively large area within the tool reduces the sound or noise-inducing impulse. A The disadvantage of this construction, however, is that the combustion gases around the functional surfaces of the tool barrel, which during of the operation to and fro, have to walk around and consequently residue build-up to an extent such surfaces occurs that the reciprocating motion of the barrel can be seriously decelerated. About that in addition, the outer sleeve hinders the introduction of the explosive charge and also hinders or prevents its use of fastener feeding devices, such as strip magazines, for the automatic feeding of fasteners one after the other into the tool.

According to ÜS-PS 3 86o 161, an attempt is made to use a integral compartment provided within the tool box or a pocket into which the combustion gases

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can expand after detonation of the cargo, a To achieve sound suppression. Since the combustion gases will follow the path of least resistance, it is This construction requires a tight fit or a tight fit between the barrel and the tool body to prevent the escape of gas through the upper part of the cargo zone. Consequently "

there is a significant risk of the barrel becoming clogged with residue or other foreign matter on the sliding surfaces.

The invention is based on the object of a simply constructed internal combustion-operated tool with a clogging-resistant tool To create noise reduction device.

This object is achieved according to the invention in a tool of the generic type solved by the features of the characterizing part of claim 1.

The invention has the advantage that a sound suppression without a resulting increase? the risk of clogging is achieved. Furthermore, with the work according to the invention ζ yours, that of relatively simple. construction is, accessibility, especially the introduction of explosive charges and / or fasteners, is not with special needs.

The invention creates a sound or noise reduction

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rer for a Brennkraftbetätiates fastening tool with a barrel that has an inner and an outer cylindrical wall which are radially spaced - to a gas expansion chamber to form between them. This chamber is for receiving combustion gases through openings or ducts geeianet in the inner wall. The gases can flow out of or out of the chamber in any suitable manner. are ejected, preferably at a location adjacent to the front end of the tool. With such an arrangement can give the outer wall of the barrel a relatively good or tight sliding fit in the tool holder will. The opening (s) of the expansion karamer can also be be so that a favorable flow pattern or a favorable streamline shape for the through this chamber outgoing combustion gases is generated.

The invention can be applied to fastening tools of various types. However, it is expedient to describe the invention with particular reference to a type of tool t which can be regarded as typical in the following. It is particularly emphasized that the invention is not limited to use in this typical tool design.

The invention is explained in more detail below with the aid of partially schematic drawings of two exemplary embodiments. Show it:

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Fig. 1 is a side view, partly in longitudinal section, of one Tool with built-in noise reducer;

Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1; Figure 3 is a cross-sectional view taken along line 3-3 of Figure 1;

4 shows a side view, partly in longitudinal section, of one second embodiment of a tool with built-in noise reducer; and

FIG. 5 is a cross section taken along line 5-5 of FIG. 4.

A typical tool to which the invention is applied can, has a main body or transducer with a cylindrical bore formed through one end la and a handpiece or handle 5 puf provided at its opposite end. A spring-operated firing pin 7 is in the earpiece end of the transducer 1 slidably attached and through

or at will a triggering device 9 selectively / releasable in order to penetrate into the bore la through the adjacent closed end of this bore .. A barrel 11 is sliding in the bore la of the transducer for a movement between a loading position and a tensioned position (ready to ignite) attached and has a charge-receiving cavity 13 or a recess in the end adjacent to the closed end of the receiving bore. When the barrel 11 is in the loading position, it is positioned forwardly relative to the susceptor so that a load can be introduced into the aforesaid cavity 13 through a window provided in the upper surface of the susceptor. In the cocked position

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the barrel 11 is in its rearmost, handle-facing position Position so that it is possible that the Laduna 15 after actuation of the release device 9 by the Firing pin 7 is hit or acted upon. Generally there is a spring device 17 for holding the barrel 11 provided in a relaxed position, which is set locally between the loading position and the cocked position and which is provided so that the charge 15 is not ignited by inadvertent actuation of the triggering device 9 can be.

A drive or thrust piston 19 is slidably mounted in a bore 11 a of the barrel 11. Between a head area 19a of the thrust piston 19 and the end wall of the barrel 11 containing the charge receiving cavity 13, a combustion chamber 21 is provided. Towards the At the mouth end of the tool, the thrust piston 19 has a reduced diameter in front of the head region 19a and thereby creates a free space 2o for receiving combustion products. Combustion products reach this free space 2o via a retraction slot 23 which is formed through the lower wall of the barrel 11 and the communicates directly with the combustion chamber 21 when the thrust piston head 19a moves out of the cocked position moved a short distance towards the front end of the tool.

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Tools of the aforementioned type are well known, so that further details regarding their construction and mode of operation may not be deemed necessary. That being said, however, it should be noted that the retractor slot 23 a locking member 25, for example in the manner of a locking pin or a pawl, which is attached to the underside of the Is attached transducer, slidably receives and that has the function of a front Grenzunassnerre for the barrel 11, and also to rearrange the thrust piston 19 with its head 19a in the vicinity of the charge-receiving Cavity 13 is used when the barrel 11 is moved into the loading position.

If a tool as described is modified to embody the invention or to incorporate the invention, the barrel 11 can be designed as a double wall construction so that a gas extension chamber 27 between the radially inner 11b and the radially outer wall lic des Run 11 is defined or limited. Since the thrust piston 19 is located within the inner wall 11b of the barrel 11 , it is necessary to form a retracting slot 23 in both walls if the locking member 25 is to serve to rearrange the thrust piston 19 as previously described, as a result of this a connection between the expansion chamber 27 and the annular free space or intermediate space 2o which surrounds the thrust piston 19. An additional device for communication or

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Connection due to openings 2 <r provided through the inner wall 11b on the side remote from the retraction slot 23 and on one toward the rear end of the barrel adjacent point are formed. The number and arrangement of these openings 29 can be determined in such a way that a subsequent to support the desired gas flow pattern described.

Gas can flow out of the expansion chamber 27 through a large number of openings 29, which are adjacent or adjacent to the front Are arranged at the end of the barrel 11, escape. For example, a green of this kind "through the inner wall 11b of the barrel 11 has openings 29 therethrough on each side

of the run
/be provided. These openings or perforations 29 lead the gas back into the free space 20 around the thrust piston 19. An escape of the gas from this zone to the atmosphere can be achieved through one or more suitable passages at the front end region of the tool. In one arrangement, the gas outflow path comprises the following in order: the aforementioned retraction slot 23, a space between the outer wall lic of the barrel 11 and the receiver core 1 in front of the locking member 25, a chamber 31 in a front end region of the receiver core 1 and finally a passage 33 which is formed by a wall of the sensor 1 and is in communication with the atmosphere.

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The aforementioned chamber 31 can be located between a front end portion of the receiving body 1 and a surrounding shield 35, which functions in a known manner, can be defined or limited.

In the structure described, the outer wall lic of the barrel 11 in the receiving bore la, at least for a part of this hole in front of the cargo window, have a good sliding fit. As a result of this, the The property or ability of the tool to suppress noise is significantly enhanced. Such a tight fit or a fit is possible, since with the described arrangement no residue build-up on the work surfaces des tool happens during combustion. Furthermore, if so desired, the outer wall lic of the barrel must be constructed in such a way that it is resiliently flexible depending on the detonation of the charge 15.

bzv- '. expands
further / and thereby instantaneously creates an essentially gas-tight seal between itself and the transducer 1. Such a seal prevents gas from escaping through the load window, which can be uncomfortable for the user, and also helps to achieve essentially complete combustion of the load 15 by maintaining a sufficient initial pressure within the tool.

Drives when using or operating the tool

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the detonation of the explosive Laduna 15 the thrust piston 19 forward and products of combustion can after the thrust piston 19 has traveled a short distance, escape from the combustion chamber 21 via the retraction slot 23. In this regard, the operation does not differ from prior art tools of the general ones described Art. Since there is little space (if any) between the outer surface of the barrel 11 and the surrounding bore surface of the transducer 1, the gas becomes this tend to move along the path of least resistance that of the expansion chamber 27 and its associated Openings 29 and passages 33 is formed. Some gas portions are grounded along the retraction slot 23 go forward or flow to flow out through the front end portion of the barrel 11 directly. An essential part of the gas, however, due to the substantial space available for pressure release, goes up into the expansion chamber 27 induced or conducted. The arrangement of the outlet openings 29 of the barrel is such that the gas in the expansion chamber 27 is caused to move in a spiral-shaped path to move towards the front end of the barrel. The resulting extension of the length of the Strömunasweg or the movement distance for the gas of course verorößern the entire pressure reduction and thereby trickle down the level the noise caused by the charge detonation is produced.

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As the combustion gases pass through a variety of chambers and connecting openings or passages flow or ventilated or be discharged, in contrast to the single high pressure imrmls that are usually found in tools is generated according to the prior art, a series of pressure pulses or bursts are generated. As a result of that, this is Noise or the sound that is generated during the detonation is significantly reduced. Even so, it is within the tool maintain sufficient pressure to ensure combustion of the powder that did not burn during the actual detonation process.

Residues or residues are emptied through the retraction slot 23 and / or in the expansion chamber 27. In both Cases, there is no adverse effect on the ignition or Combustion process. This is a major difference to constructions according to the state of the art, in which residues be dumped on one or more of the critical work surfaces of the tool.

Another advantage of the construction described is that it provides effective noise suppression without adverse effects Impairment of the charge loading device of the tool is achieved. As mentioned before, the one here Specially described construction is only a construction embodiment. For example, more than an expansion chamber 27 can be provided and this

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Chambers are arranged concentrically and / or in axially offset relationship to one another. Furthermore could the invention can also be applied to a tool or apparatus which has an automatic strip feed of charges as well as manual feeding or manual reloading of individual loads through a window, according to the description.

In the accompanying drawings are two possible inventive Embodiments shown. However, the peculiarity should These drawings are not to be understood in the sense that they represent the general idea or general validity replace the previous description.

Ultimately, it goes without saying that different alternatives, Changes and / or additions to the constructions and arrangements of the parts described above may be introduced without departing from the spirit, idea, or scope of the invention.

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Claims (6)

Expectations 1.J Brennkraftbetätiqtes tool with a pickup, which at one end has a cylindrical Blind hole and at the other end has a handle / a barrel, egg a load-receiving cavity and a includes axial bore and in the blind bore of the receiver for movement between a loading position and a tensioned Stelluno is slidably arranged, the barrel having the charge-receiving cavity in its closed Has the end of the blind bore of the transducer adjacent end, and a spring-operated firing pin that slides in the end of the retainer of the transducer is attached and which can be selectively released by a release device, characterized, that the barrel (11) has at least two cylindrical, concentric, radially spaced elements (Hb, lic) which between an expansion chamber is formed, and that all elements, except for the outermost element (lic) of the barrel, a Durchgangseinrichtunq (29) have, which for the passage of Verbreiinungscrasen between the bore (Ha) of the barrel and the expansion chamber (27) is suitable. 2. Tool according to / \ nsnruch 1, characterized in that that a drive piston (19) slidably in the barrel bore (11a) and a locking member (25) on the underside of the receptacle 909842/0786 ORiGtNAL INSPECTED (1) is attached, which is in a retractor slot (23), the is formed in the barrel (11), protrudes, and that the passage device (29) has a plurality of openings (29) in all girders except the outermost of the barrel / at a first location adjacent to the rear end of the barrel, at its remote from the retraction slot (23) Side, are formed. 3. Tool according to Ansoruch 1 or 2, characterized in that that the passage device (29) has a plurality of openings (29), which in all elements (11b, 11c), except the outermost of the barrel, are adjacent at a second location to the front end of the barrel (H) / are formed. 4. Tool according to one of claims 1 to 3, characterized in that that a chamber (31) in the front end of the transducer (1) ge ~ is formed with the retraction slot (23) by a (20) Space / is connected between the barrel (11) and the receiver (1) before the locking member (25), and that at least one formed in the receiver (1) through (33) connects the ^one chamber (31) with the atmosphere. . 5. Tool according to claim 3 or 4, characterized in that the openings (29) at the second point on both 909842/0788 the sides of the barrel (11) are arranged. 6. Tool according to one of claims 1 to 5, characterized , that the outer element (lic) of the barrel on a
Detonation of a charge (15) in the charge-absorbing cavity (13) is resiliently expandable to create momentarily a gas-tight seal between the outer element (lic) of the barrel (11) and the receiver (1). 909842/078 3