Combustion-powered setting tool

Abstract

A combustion-powered setting tool (1) with a combustion chamber (24), a housing unit (4) for receiving a gas cartridge (17), a cylinder (27) containing vent holes 42 and exhaust openings 43, for receiving and guiding a piston (25) with piston head (26), a cylinder head 20, a muzzle part (31) and a buffer (40), characterized in that the setting tool 1 has closable valve openings (53) and (54) and the cylinder (27) form a non-displaceable unit with the combustion chamber 24 and the cylinder head (20).

Description

[0001] The invention relates to a combustion-powered setting tool for driving fasteners according to the preamble of claim 1.

[0002] As can be seen from US Patent Re. 32,452, US Patent 4,522,162, US Patent 4,483,474 and US Patent 4,403,722, a combustion-powered setting tool typically has a combustion chamber defined by a cylinder body with a piston and by a combustion chamber designed to open and close, and a cylinder head. In such a device, a piston is movably mounted in a cylinder to be propelled by the explosion of an air and fuel gas mixture injected into a combustion chamber from a gas cartridge and to drive in a fastener such as a nail, dowel or other means. The fasteners are stored in a magazine located in the area of ​​the muzzle of the setting tool. Operation is prevented by a support safety device if the setting tool is not pressed against a substrate.The support guard, located near the nozzle, is connected to the combustion chamber by a device, so that the combustion chamber forms openings between the cylinder, which guides the piston, and the cylinder head. These openings are closed when the setting tool is pressed against a surface. The cylinder head carries a spark plug that ignites the air and fuel gas mixture, and a fan that mixes this mixture.

[0003] Typically, the exhaust gases are directed directly to the outside through large openings in the housing.

[0004] A disadvantage of these conventional setting tools is that the combustion chamber must be guided axially on the cylinder. The combustion chamber guide elements in conventional setting tools are designed simply. This can cause the combustion chamber to jam when the setting tool is pressed against a surface, if the combustion chamber is intended to form a sealed combustion chamber with the cylinder and the associated cylinder head.

[0005] The object of the present invention is therefore to develop a setting device of the aforementioned type in which the combustion chamber is no longer displaceable relative to the cylinder and cylinder head and the ventilation and final ventilation of the combustion chamber is effected via valves.

[0006] According to the invention, the object is achieved in that the combustion chamber has at least one valve for ventilation with fresh air and at least one valve for venting the exhaust gases.

[0007] This problem is solved according to the characterizing part of claim 1.

[0008] Further embodiments of the invention can be found in the following description and the subclaims. Fig. 1 shows in perspective a combustion-powered setting device according to the invention Fig. 2 shows a partial axial section of a combustion-powered setting tool with a movable combustion chamber Fig. 3 shows a partial axial section of a combustion-powered setting tool according to the invention Fig. 4 shows in perspective a combustion-powered setting device according to the invention with an exhaust system Fig. 5 shows in perspective a combustion-powered setting device according to the invention Fig. 6 shows a section of a combustion-powered setting device according to the invention Fig. 7 shows a partial axial section of a combustion-powered setting tool according to the invention Fig. 8 shows a partial axial section of a combustion-powered setting tool according to the invention with the valve in the open position Fig. 9 shows a partial axial section of a combustion-powered setting device according to the invention with closed valve position

[0009] Fig. 1 to Fig. 3 shows a combustion-powered setting tool 1 with a housing part 2 for accommodating a cylinder 27, which in turn accommodates the piston 25 with its piston head 26, a combustion chamber 24, a cylinder head 20, which is equipped with a fan motor 21 with a rotor 23. The housing part 2 is provided with a housing cap 30 on the rear. The mouthpiece 31 carries the support lock 10, which can be axially displaced via a depth adjustment 11 in order to influence the setting depth of the fastening elements (not shown). The magazine 5 for the fastening elements is arranged between the mouthpiece 31 and the handle 3. The magazine slide 6 feeds the fastening elements (not shown) to the mouthpiece 31. The magazine 5 is connected to the handle 3 via the lock 8. The handle 3 carries a holder 12 and accommodates the battery 7 in the rear part. A housing unit 4 for accommodating the gas cartridge is formed between the handle 3 and the housing part 2.Below the gas cartridge is a trigger 35 with a switch 34 for controlling the electronic ignition unit (not shown in full). When the setting tool 1 is pressed against a surface, the bracket 41, which is attached to the trigger 35, can lock the combustion chamber 24 in the closed position via the groove 39 when the trigger 35 is pulled. The combustion chamber 24 is in contact with a slide 37, the base part 38 of which projects into the housing unit 4 to accommodate the gas cartridge 17. Advantageously, a gap forms between the base part 38 and the gas cartridge 17, so that a displacement of the combustion chamber 24 triggers the displacement of the gas cartridge 17 with a delay. The locking unit 9 is arranged on the housing unit 4. The housing unit 4 advantageously forms a curved track 16 that can accommodate the axis 13 of the locking unit 9.Via the cam track 16 in conjunction with the axis 13 and the cam 29 arranged on the locking unit 9, the locking unit 9 can be locked to the housing unit 4 and to the housing cap 30 by a simple pivoting movement. The locking unit 9 accommodates a connecting element 14, which is movably arranged in the locking unit 9. For connection to the setting tool, the connecting element 14 has an extension 15, which is tubular in shape here, for example. The extension 15 can be formed integrally with the connecting element 14 or, as shown here, in two parts. The connecting element 14 can accommodate the outlet 18 of a gas cartridge 17 when locking the locking unit 9. The connecting element 14 is held in the locking unit 9 under spring load by a spring 22. The buffer 40 is mounted on the front side of the muzzle part 31 and is located within the cylinder 27 of the piston guide.The cylinder 27 is connected to the muzzle part 31. . Fig. 3 shows the cylinder 27, which contains vent holes 42 and exhaust ports 43. The exhaust ports 43 are provided with the known check valves (not shown in full), which are connected via the shaft 44 and the transition channel 45 to the Fig. 4. The ventilation holes 42 also use the channel formed by the transition channel 45 and the exhaust system 46. The exhaust system 46 extends from the housing 2 as an exhaust and ventilation guide largely parallel to the handle 3 and thus forms a closed channel. Known means for reducing sound pressure (not shown) can be installed within this channel of the exhaust system 46. In this preferred example, the exhaust system 46 forms a support for the magazine 5. At the lower end of the handle 3, the exhaust system 46 preferably has an outlet opening 47. The outlet opening 47 can be oriented as desired, but should, if possible, point away from the user when using the setting tool 1. Fig. 5 and Fig. 6 show a combustion-powered setting tool according to the invention, in which the combustion chamber 24 is designed in one piece with the cylinder 27. The cylinder head 20 is in direct contact with the combustion chamber 24. The gas cartridge 17 is arranged here in the housing unit 4 of the housing part 2. The closure unit 9 can be pivoted laterally via the rotation axis 46 for opening, whereby the gas cartridge 17 can be inserted or removed. The closure unit 9 is spring-loaded via the rotation axis 46, so that the closure unit 9 is automatically returned to the starting position as shown in Fig. 5 shown swings back. Fig. 7 and Fig. 8 show a combustion-powered setting tool according to the invention, in which the valve openings 53 and 54 are open. These valve openings 53 and 54 are controlled, as shown here, by a valve piston unit 51. The valve piston unit 51 can be equipped with piston or O-rings 55 and 56. Guide surfaces 52 and 57 can be provided for better guidance of the piston or O-rings 55. The valve piston unit 51 can be axially displaced by means of a push rod 47, which is held in its initial position by a spring 49 via stops 48 and 49. The spring 49 can be supported against buckling during compression by means of a sleeve 58. The openings 53 and 54 can also be opened or closed by separate valve units (not shown), which are, for example, electrically driven systems. The opening and closing of the valve openings 53 and 54 can take place at different times, i.e.The valve opening 53 can close while the valve opening 54 is still open. This allows additional fresh air to be introduced into the combustion chamber 24.

[0010] Fig.Figure 9 shows a combustion-powered setting tool according to the invention, in which the valve openings 53 and 54 are closed. When the setting tool 1 is pressed against a substrate, the support lock 10, which is axially displaceable via a depth adjustment 11, and the push rod 47, which is in contact with the valve piston unit 51, can close the valve openings 53 and 54. This axial displacement of the support lock 10 actuates the cam 59, causing the gas cartridge 17 to release fuel into the combustion chamber 24. The rotor 23 mixes the fuel with the fresh air, creating an ignitable mixture that can be ignited by an ignition unit (not shown). The combustion process drives the piston 26, and a nail (not shown) can be driven into the substrate.After the setting tool 1 is lifted, the valve openings 53 and 54 open, allowing the exhaust gas to flow out of the combustion chamber 24 via the valve opening 53 by means of the rotor 23, and fresh air to be drawn in for refilling via the valve opening 54. Additionally, the valve opening 54 can also be equipped with an air flow generator (such as a fan, compressor, or turbocharger) not shown in order to introduce excess air into the combustion chamber 24.

Claims

[1] A combustion-powered setting device (1) with a combustion chamber (24), a housing unit (4) for receiving a gas cartridge (17), a cylinder (27) containing vent holes 42 and exhaust openings 43, for receiving and guiding a piston (25) with piston head (26), a cylinder head 20, a muzzle part (31) and a buffer (40), characterized by that the setting device 1 has closable valve openings (53) and (54) and the cylinder (27) with the combustion chamber 24 and the cylinder head (20) form a non-displaceable unit. [2] A combustion-powered setting device (1) according to claim 1, characterized by that the valve openings (53) and (54) are opened and closed via a valve piston unit (51). [3] A combustion-powered setting device (1) according to claim 1 to 2, characterized by that the valve openings (53) and (54) are controlled at different times. [4] A combustion-powered setting device (1) according to claims 1 to 3, characterized by that the valve openings (53) and (54) are provided with guide surfaces (52) and (54) for piston or O-rings (55) and (56).

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