MXPA98008983A - Tool driven by combustion with a closure for the combust camera - Google Patents

Abstract

The present invention relates to a combustion-driven tool that has an internal combustion power source built in and placed to create a combustion to drive a drive blade to collide with a fastener and push it into a workpiece, which comprises: a box built and placed to enclose the source of power, a combustion chamber defined in the box, a cylinder placed in the box to be in fluid communication with the combustion chamber, a piston associated with the driving blade and configured to move reciprocally within the cylinder between a starting position located at a first end of the cylinder and a pulse position located at a second end of the cylinder; gas control mechanisms to open the combustion chamber to the atmosphere when the tool is not contact with a work surface, a trigger switch assembly placed in the box and including a trigger, a closing mechanism connected to the trigger switch assembly to prevent combustion in the combustion chamber until the chamber is thermospherically sealed, and delay mechanisms connected to the trigger switch assembly to delay the opening of the combustion chamber by the closing mechanism after releasing the trigger and until the piston returns to the starting position after pushing the clamp

Description

TOOL DRIVEN BY COMBUSTION WITH A CLOSURE FOR THE COMBUSTION CHAMBER BACKGROUND OF THE INVENTION The present invention, in general, relates to improvements in tools for placing fasteners that are driven by combustion, and specifically relates to improvements related to the opening delay after combustion of the combustion chamber. to allow the piston to return properly to the initial position. Tools of this type, known as IMPULSE®, Portable, combustion-driven for use with fasteners driven or placed in workpiece are described in the patents commonly assigned to Nikolich: Re. U.S. Patent No. 32,452 and patents from the United States Nos. 4,552,162; 4,483,473; 4,483,474; 4,403,722 and 5,263,439, which are incorporated herein by reference. Similar, combustion driven tools that place staples and nails are commercially available from ITW-Paslode of Lincolnshire, Illinois under the IMPULSE® brand. These tools have a generally gun-shaped housing that contains a small internal combustion engine. The engine is activated by a fuel gas can, under pressure, which is also known as a fuel cell. The electronic energy distribution unit that uses a battery produces a spark for the start-up, and a fan placed in the combustion chamber is provided which helps both to have a more efficient combustion and to facilitate the expulsion, including the escape of the secondary products of combustion. The motor includes a reciprocating piston with a rigid, elongated driving blade, which is disposed within the cylindrical body. A valve sleeve is axially reciprocal about the cylinder and, through a link, moves to close the combustion chamber when the contact work element is pressed at the end of the link against the workpiece. This pressing action also drives a fuel metering valve to introduce a specific volume of fuel into the closed combustion chamber. After pulling the trigger switch, which causes the ignition of the gas charge in the combustion chamber of the engine, the piston and the drive blade are struck down to strike the fastener in place and propel it towards the work piece. Then the piston returns to its original position, or "ready" position, through the differences in gas pressure inside the cylinder. The fasteners are in a reservoir or feeding chamber that provides them in the nose piece, where they are held in an orientation placed in an appropriate manner to receive the impact of the driving blade. One of the criteria for designing conventional combustion tools is that the trigger can not be activated or operated until the nose of the part, or tool, is pressed against the work piece. This aspect delays the ignition until the combustion chamber is closed. In U.S. Patent No. 4,483,474 it presents an adequate mechanism for closing or blocking the trigger, which is incorporated herein by reference. In the patent 474, a cam and a lever mechanism prevent the trigger from being pulled until the nose piece is pressed against the work piece, closing the combustion chamber. After activation, the combustion chamber can not be opened until the trigger is released. A recent development in combustion tools is the creation of high-energy tools that produce more force to drive the fasteners into the workpiece. In some of these tools, the additional force is obtained with the use of an extended cylinder through which the piston travels, thus a piston with a longer stroke is provided. In other designs with higher energy, the volume of the combustion chamber is increased. In this designs, you try to minimize the surface area, increased, of the combustion chamber, and the surface area can remain the same. There is more combustion energy, but equivalent there is no more surface area to cool and a differential pressure is created to return the piston to its initial position. Consequently, the piston returns more slowly. In tools with a longer length, the time it takes to return the piston while increasing the length of the cylinder increases. It was found that, in some of the recently developed, high-energy combustion tools, the piston requires approximately twice the length to return to its initial position, than that required by conventional combustion tools that have a relatively longer stroke. short. Obviously, the tool should not be turned on until the piston has completely returned to its initial position. In the equipped combustion tools described above, in the event that the switch trigger is released and the tool is lifted from the workpiece before the piston has returned to its initial position, the valve connection allows the the combustion chamber is opened, thus eliminating the difference in gas pressure that assists in the upward movement in the return of the piston. In order to have consistent shots, the size of the combustion chamber must always be the same. Accordingly, it is an object of the present invention to provide an improved combustion driven tool that prolongs the sealing condition in the combustion chamber until the piston has returned to its initial position prior to combustion. Another object of the present invention is to provide an improved combustion driven tool having mechanical characteristics to keep the combustion chamber closed until the piston returns to its initial position. Another object of the present invention is to provide an improved combustion driven tool in which the combustion chamber is kept closed until the piston returns to its position by means of a mechanism that delays the release of the trigger switch, and through a connection with a closing mechanism, thus the opening of the combustion chamber is definitively retarded. A further objective of the present invention is to provide an improved combustion driven tool having a trigger switch that is relatively easy to press or activate when it returns to its initial, non-active position.

BRIEF SUMMARY OF THE INVENTION The objects mentioned above are achieved or even exceeded by the present tool driven by improved combustion, which has a delay apparatus to delay the opening of the combustion chamber after combustion until the piston has returned to the combustion chamber. your initial position In the embodiment, the tool has a mechanism, operated with a trigger, that closes the combustion chamber, which prevents the combustion chamber from opening, when it is not desired, until the trigger is released after which it shoots. The delay apparatus delays the movement of the trigger from the ON position to the OFF position, thereby providing additional time for the piston to return to its initial position. More specifically, the present invention provides a combustion-driven tool that has an internal source of energy for combustion which is constructed or arranged to create a combustion that drives a blade that impacts the fastener and propels it toward the workpiece . The tool of the present invention includes a housing constructed and arranged to contain an energy source, a combustion chamber defined at an upper end of the housing, a cylinder disposed in the housing which is in fluid communication with the combustion chamber. , a piston associated with a driving blade and configured to perform a reciprocal movement within the cylinder between the initial position placed at the first end of the cylinder and the driven position placed at the second end of the cylinder, a device for controlling the gas to periodically open the combustion chamber into the atmosphere, and a delay apparatus connected to the gas control device to delay the opening of the combustion chamber until the piston returns to its initial position after the fastener is driven.

BRIEF DESCRIPTION OF THE DIVERSE VIEWS OF THE DRAWINGS Figure 1 is a fragmentary, side view of a combustion-driven fastener tool according to the present invention, showing the combustion chamber open and the trigger or trigger in the OFF position, the tool is presented in a partial cut for clarity; Figure 2 is a fragmentary, side view of a combustion driven fastener tool of Figure 1, showing the combustion chamber closed and the trigger in the ON position, the tool is presented in a partial cut for greater clarity; Figure 3 is an enlarged sectional view of the trigger assembly and pneumatic retard valve of the present invention, presented in the OFF position; and Figure 4 is a partial, enlarged sectional view of the trigger assembly and the pneumatic retard valve of Figure 3, which is shown in the ON position.

DETAILED DESCRIPTION OF THE INVENTION Referring now to Figures 1 and 2, the combustion driven tool of the type suitable for use with the present invention is generally designated with the number 10. The tool 10 has a housing 12q which includes a camera for the main power source 14 with the dimensions to fit the internal source of energy for combustion 16, the fuel cell chamber 18 is generally parallel and adjacent to the main chamber 14, and the portion of the handle or handle 20 which extends from one side of the fuel cell chamber and opposite the main chamber. In addition, the feeder reservoir 22 is generally positioned to extend parallel to the handle portion 20 from the point of engagement with the nose piece 26, depending on the first and second end 28 of the main chamber 14. provides a battery (not shown) for supplying electrical power to the tool 10, and is received, releasably, in a tubular compartment (not shown) located on the opposite side of the housing 12 from the Feeding reservoir of fasteners 22. According to its use in the present, "lower" and "upper" are used to refer to the tool 10 is operational guidance as presented in Figures 1 and 3; however, it will be understood that this invention can be used in a variety of orientations depending on the application. The opposite lower end 28 of the main chamber is the second end, or upper end 30, having a plurality of vents for the air inlet 32. In a preferred embodiment, a solenoid-type fuel gauge valve is provided. , electromagnetic (not shown) or an injection valve of the type described in U.S. Patent No. 5,263,439 for introducing or supplying fuel to the combustion chamber as known in the art. The patent identified with No. 5,263,439 is incorporated herein by reference. The fuel cell containing a liquid hydrocarbon under pressure, such as MAPP, is placed in the chamber of the fuel cell 18 and pressurized with a propellant as is known in the art.

Back in the main chamber 14, the head of the cylinder 34 is disposed at the upper end 30 of the main chamber, defining an upper end of the combustion chamber 36 and with a mounting point for a head switch 38, a spark plug 40, an electric motor for the fan 42 and an O-ring for sealing 44. The fan for the combustion chamber 46 is attached to the structure 48 of the motor 42 or placed inside the combustion chamber to improve the combustion process and to facilitate cooling and exhaust. The fan motor 42 is controlled by the head switch 38, as shown in more detail in the aforementioned patents which are incorporated herein by reference. The reciprocal valve member, generally cylindrical 50, moves within the main chamber 14 by an element that is in contact with the workpiece 52 in the nose piece 26 using a connection 54 in the known manner. The valve member 50 serves as a device for controlling the gas in the combustion chamber 36, and the side walls of the combustion chamber are defined by the valve member, the upper end of which comprises an o-ring 44 to seal the upper end of the combustion chamber (which is best seen in Figure 2). The lower portion 56 of the valve member 50 circumscribes a body of the cylinder or cylinder 58. The upper end of the cylinder body 59 has an O-ring 60 that engages with the corresponding portion 62 of the valve member 50 (which can be seen better in Figure 2) to seal the lower end of the combustion chamber 36. Within the cylinder body 58 there is reciprocally disposed a piston 64 which is attached to an elongated, rigid driving blade 66 used to drive the fasteners (not shown), properly positioned in the nose piece 26, towards the workpiece (not shown). The lower end of the cylindrical body defines a seat 68 for a shock absorber 70 that defines a lower limit of travel or displacement of the piston 64. At the opposite end of the cylinder body 58, a retaining ring is fixed to stop the piston 72 to limit the downward travel of the piston 64. The controls for operating the tool 10 are located on the handle portion 20 of the housing 12. The trigger switch assembly 74 includes a trigger switch 76, a trigger 78 and a return member. flexed 80, which, in the preferred embodiment in a spiral spring. The unit for the electric control 82 under control of the trigger switch 76 activates the spark plug 40.

The operation of the trigger 78 between the OFF position (FIG. 1) and the ON position (FIG. 2) is controlled by means of a cam or trigger closing mechanism, generally referred to as number 84, which prevents the trigger from being activated. unless the tool 10 is pressed against the work piece. This pressure causes the nose piece 26 to sink, causing the connection 54 to move the valve member 50 upwards to close the combustion chamber 36 and seal the air inlet. More specifically, and in reference now to the Figures 1-4, the locking mechanism 84 includes a support for the trigger 86 which is secured to one end of the trigger 78 and in the other has an angle arm 88 that is provided with a transverse pivot pin 90. Generally, the cam of release, in triangular shape 92 that engages with the pin 90 has an open end slot 94 with the necessary dimensions to engage, slidably, the pin 90. Also in the cam 92 there is provided a through hole 96 which is hooked in shape coupled with the pivot 98, and a stabilizing tab of the cam 100. Referring now to Figure 1, the stabilizing tab of the cam 100 engages at one end of a generally U-shaped bar 102, when the combustion chamber 36 opens to the atmosphere. This latch prevents the trigger or trigger 78 from being depressed, and thus prevents ignition. Referring now to Figure 2, since the u-shaped bar 102 is attached to the valve member 50, while the combustion chamber 36 is closed by means of the valve member, the bar 102 moves upwards with the member of the valve, which creates a release for the movement of the release cam 92 after the bar. With the cam 92 free to move, the trigger 78 can be depressed to cause the ignition. This closing mechanism 74 is described in more detail in U.S. Patent No. 4,483,474. As the trigger or trigger 78 is pulled, a signal is generated from the central distribution and control unit of the electricity 82, to cause a discharge in the electrode spacing of the spark plug 40, which ignites the fuel that was injected in the combustion chamber 36 and vaporizing or fragmenting with the fan 46. The ignition forces the piston 64 and the driving blade downwards along the cylinder body 58 until the driving blade touches a fastener and places or inserts it in the substrate in the manner known in the art. Then, the piston returns to its original position or "list" through the pressure difference inside the cylinder, which is maintained in part by the sealed condition of the combustion chamber. If the combustion chamber 36 is opened before the piston returns to its initial position, which is seen in Figures 1 and 2, the differential pressure ratio of gas is destroyed, which interferes with the return of the piston. It was found that when the combustion driven tools have a relatively long cylinder body 58 or a wide combustion chamber, additional time is required for the piston 64 to return to the initial position, as seen in Figures 1 and 2. These models, there is a potential, after the release of trigger 78, so that the combustion chamber is opened before the right time. It will be appreciated in Figures 1 and 2 that as long as the trigger 78 remains depressed, the U-shaped bar 102 can not be moved downward to release the valve member 50 from its position, sealing the combustion chamber. However, once the trigger 78 is released, the cam 92 moves to the position of Figure 1 and allows the bar 102 to move downward, opening the combustion chamber. As mentioned above, it is important that the combustion chamber 36 does not open before the piston returns to the initial position. Thus, an important aspect of the present invention is the provision of the retarder apparatus for delaying the opening of the combustion chamber. In the preferred embodiment, this is achieved by delaying the release of the trigger 78 from its depressed or ON position, until the piston 64 returns completely. Referring to Figures 3 and 4, the retarder apparatus of the invention, generally designated with the numeral 104, as well as in the preferred embodiment, has a pneumatic check valve configured to retard the action of the flexed back or spring member in spiral 80, which returns the trigger 78 to the released or OFF position, which is shown in Figure 3. The pneumatic check valve includes a cavity 106 defined by an internal, generally cylindrical, wall 108 positioned within the trigger 78. The pushbutton 110 is fixed at the end of the base 112 to support the formation in the housing 12 by tight friction, the threaded fastener or any other type of fastener known in the art. At the opposite end or tip 114, the push-button 110 engages in engagement with the cavity 106. In the preferred embodiment, the push-button 110 is equipped with a seal member 116 secured within the annular groove 118 located near the tip 114. The friction fit and / or chemical adhesives can be used to secure the sealant member 116 in place. Sealing member 116, preferably known as a "U-shaped cup" seal, has an outer lip 120 that projects at an oblique angle relative to the longitudinal axis of push button 110 to form a tongue or a configuration of the type of arrow head. Thus, the lip 120 engages, neatly, with the inner wall 108 of the cavity 106 and creates a friction that counteracts the action of the return flexed member 80 and retards the return of the trigger 78 to the OFF position. In other words, the sealing member 116 is disposed on the push button 110 so that the trigger is easily pulled to the ON position (Figure 4), but slowly returns to its OFF position (Figure 3). When the trigger 78 is depressed, the movement of the trigger on the pusher 110 forces a substantial amount of vertical air from the cavity 106, creating a relative void in the region 122 of the cavity behind the sealing member 116. Due to the coherent imperfections in the sealing member 116, which preferably is made of buna-N or butyl rubber, or equivalents, a total vacuum is not achieved and, as a result of the force applied by the flexed return member 80, the air it slowly escapes in region 122, thus allowing spring 80 to push trigger 78 to return to the OFF position. Those skilled in the art will appreciate that the sealing member 116 should not be made to create a total seal, so as to create a vacuum that can prevent the trigger 78 from returning to its OFF position. In some applications, the lip 102 can be coated with grease to slide more easily into the cavity 106. In the preferred embodiment, the pusher 110 and the cavity 106 have the dimensions such that the vacuum that occurs in the region 122 is sufficient to delay the placement of trigger 78 in the OFF position until piston 64 returns to the initial position. It has been found that incorporation of the delay apparatus of the present invention 104 into the tool 10 generally requires twice as much time to return the trigger 78 to its OFF position when compared to conventional combustion driven tools. When equipped with the apparatus of the present invention, the time necessary for the trigger 78 to reach its OFF position from the ON position is approximately 200 milliseconds. Thus, it will be appreciated that the retardation mechanism of the present invention, in the form of a pneumatic valve, provides sufficient delay in the movement of the trigger to its OFF position, and finally, retards the opening of the combustion chamber 36 until the piston 64 reaches its initial position. It will be appreciated that other mechanisms known to those skilled in the art may be used to keep the combustion chamber closed until the piston reaches its initial position, and this still belongs to the scope of the invention. While a particular embodiment has been presented for closing the combustion chamber in the combustion driven tool of the invention, those skilled in the art will appreciate that changes and modifications may be made thereto, without departing from the broad aspect of the invention and in accordance with what is specified in the appended claims.

Claims (12)

1. A combustion driven tool that has an internal combustion energy source constructed and arranged to create the combustion that drives a driving blade to strike the fastener and apply it to the work piece, this tool comprises: a housing constructed and arranged to contain The source of energy; a combustion chamber defined at the upper end of the housing; a cylinder disposed in the housing that is in fluid communication with the combustion chamber; a piston associated with the driving blade and configured to reciprocate with the cylinder within the cylinder between the initial position placed on the first end of the cylinder and the active position placed on the second end of the cylinder; the gas control mechanism for periodically opening the combustion chamber to the atmosphere; and the delay mechanisms connected to the mechanism for controlling the gas, to retard the opening of the combustion chamber until the piston returns to its initial position after it drives the fastener.

2. The tool according to claim 1, in which this tool includes a trigger switch assembly having a trigger that operates between the OFF and ON position, the retarder mechanism is configured to delay the movement of the trigger from the ON position to the OFF position until the piston returns to its initial position.

The tool according to claim 2, wherein the trigger switch assembly includes this trigger, a trigger switch, a flexed return member and a pneumatic check valve configured to delay the action of the flexed member back.

The tool according to claim 3, in which the pneumatic check valve includes a cavity with the internal walls located in the trigger, the push-button is fixed in the housing and is hooked, in a coupled manner, in the cavity, The pusher has a seal member to neatly engage the inner walls, so that it engages the sealing member with the cavity to create a friction that counteracts the action of the bent member back and delays the return of the trigger to its OFF position.

5. The tool according to claim 4, wherein the sealing member has a lip projecting at an angle relative to the longitudinal axis of the push button.

The tool according to claim 1, wherein the mechanism for controlling the gas is a reciprocal valve member that moves within the housing by means of a contact element with the workpiece, the valve member being builds and arranges to seal, so that it can be released, the combustion chamber of the atmosphere, the tool includes a trigger switch assembly that has a trigger that operates in the OFF and ON positions, and a mechanism to close the trigger , this mechanism is configured to delay the opening of the valve by means of a closing mechanism, delaying the movement of the trigger to its OFF position.

The tool according to claim 6, wherein the trigger switch assembly has a trigger, a trigger switch, a flexed or bent return member and a pneumatic check valve configured to retard the action of the return spring.

The tool according to claim 7, in which the pneumatic check valve includes a cavity with internal walls placed on the trigger, a pushbutton fixed to the housing and hooked, coupled to the cavity, the pushbutton has a sealing member for neatly engaging the inner walls so that the engagement of the sealing member with the cavity creates the friction that counteracts the action of the bent spring member, and delays the return of the trigger to its OFF position.

9. A combustion-driven tool having an internal combustion energy source constructed and arranged to create the combustion that drives a driving blade to strike the fastener and apply it to the workpiece, this tool comprises: a housing constructed and arranged to contain the power source; a combustion chamber defined at the upper end of the housing; a cylinder disposed in the housing that is in fluid communication with the combustion chamber; a piston associated with the driving blade and configured to reciprocate with the cylinder within the cylinder between the initial position placed on the first end of the cylinder and the active position placed on the second end of the cylinder; a trigger switch assembly disposed in the housing and connected to the power source to initiate combustion in the combustion chamber, the trigger switch assembly includes a trigger that operates between the OFF and ON positions; the assembly of the valve for sealing, so that it can be released, the combustion chamber from the atmosphere; the delay mechanism connected to the trigger switch assembly to delay the opening of the combustion chamber until the piston returns to the initial position after it drives the fastener, the delay mechanism incorporates a vacuum assisted friction force to delay the movement of the trigger from the ON position to the OFF position until the piston returns to its initial position.

10. A combustion driven tool having an internal combustion energy source constructed and arranged to create the combustion that drives a driving blade to strike the fastener and apply it to the workpiece, this tool comprises: a housing having a main camera which encloses the source of energy; a combustion chamber that is defined within the main chamber; a cylinder inside the main chamber and a piston, the cylinder encloses the piston to drive the driving blade toward the fastener as the piston is pushed towards the second end of the cylinder, and the piston is configured to reciprocate within the cylinder between the initial position located at the first end of the cylinder and the driven position located at the second end of the cylinder; the trigger switch assembly arranged in the housing and connected to the power source to initiate combustion in the combustion chamber, the trigger switch assembly includes a trigger or trigger that operates between the ON and OFF positions; the valve assembly for releasing, so that it can be released, the combustion chamber of the atmosphere; the closing mechanism connected to the trigger switch assembly and the valve assembly to prevent the combustion chamber from opening to the atmosphere until the trigger is released from the position SWITCHED ON; and the delay mechanism connected to the trigger switch assembly to delay the opening of the combustion chamber until the piston returns to the initial position after it drives the fastener.

The tool according to claim 10, wherein the delay mechanism is configured to delay the return of the trigger to the OFF position.

12. The tool according to claim 10, wherein the trigger switch assembly includes a trigger and a bent return member, and the delay mechanism includes a pneumatic check valve which, in turn, includes a cavity with localized interior walls in the trigger, and a push-button fixed to the housing and hooked, in a coupled manner, in the cavity, the push-button has a sealing member to hook, in a clean manner, the internal walls so that the sealing member engages with the cavity creating a vacuum, improved by friction that counteracts the action of the return member, bent, and delays the return of the trigger to its OFF position.