SYSTEM OF THE STABILIZER OF THE CARRIER AND CONTROL OF SPEED FOR TOOLS WITH COMBUSTION ENGINE
BACKGROUND OF THE INVENTION The present invention relates generally to improvements in portable combustion engine fastener driving tools, and specifically to improvements related to the control of output power and the maintenance of a stable alignment of a tool such as those mentioned in a work piece. Portable combustion engine tools, or brand-name tools called IMPULSE® for use in drive fasteners within workpieces, are described in the patents commonly assigned to Nikolish, US Patent Reference Number 32,452, and US Patent Nos. 4,552,162 , 4,483,473, 4,483,474, 4,403,722 and 5,263,439, all of which are incorporated by reference herein. Nail drive tools and staples with a similar combustion engine are commercially available from ITW-Paslode of Lincolnshire, Illinois under the IMPULSE® brand. These tools incorporate a tool frame that contains a small internal combustion engine. The engine is powered by a pressurized fuel gas receptacle, also called a fuel cell. A battery powered electronic power distribution unit produces the spark for ignition, and a fan located in the combustion chamber provides efficient combustion within the chamber for both, and facilitates sweeping, including the discharge of secondary products from the combustion chamber. the combustion. The engine includes a reciprocating piston with an elongated and rigid blade of the drive mechanism disposed within a piston chamber in the body of a cylinder. The valve sleeve is axially reciprocable in relation to the cylinder and, through a link, moves to close the combustion chamber when a work contact element at the end of the link is pressed against a work piece. This pressure action also activates a fuel metering valve to introduce a specified volume of combustible gas into the closed combustion chamber. After triggering the trip switch, which ignites a gas charge in the combustion chamber of the engine, the piston and the drive blade are fired down to impact a positioned bracket and push it into the Workpiece. As the piston is driven down, a displacement volume contained in the piston chamber below the piston is forced towards the outlet through one or more outlet ports disposed at the lower end of the cylinder. After the impact, the piston then returns to its original or "ready" position through differential pressures of the gas inside the cylinder. The fasteners are fed loader style into the nosepiece, where they are held in an appropriately positioned orientation to receive the impact of the drive blade. The combustion engine tools can show differences of conventional powder gun activated (PAT) tools, which employ a cannon-powered cartridge to propel the thrust member in order to drive a fastener into a workpiece . The PAT tools generate an explosion in a combustion chamber that creates high pressures to urge the thrust member at a high speed toward the fastener. The relatively small volume of the combustion chamber and the explosive combustion combine to create a rapid acceleration of the thrust member for the speed required for the proper thrust of the fastener. In contrast, combustion engine tools usually provide much slower acceleration than the thrust member. This is due to the relatively large size of the combustion chamber, and the requirement of the preferred fuel to obtain atmospheric oxygen for combustion (gunpowder in the PAT tools incorporates its own oxygen). Therefore, in combustion engine tools, the combustion process is a relatively gradual process. The commercially available combustion engine tools have relatively short cylinder bodies, so the thrust member is unable to achieve speeds comparable to those of the PAT tools. A tool with a high-speed combustion engine of the type described above and having an extended cylinder or piston chamber is the subject of the pending patent application, serial number 08 / 536,854, filed on September 29, 1995. The cylinder Extended piston stroke increases, thereby allowing increased piston speed and energy transfer from the drive blade to the fastener. In one embodiment, the extended length also allows an operator to remain standing generally during the drive of the fasteners that are at floor level. A number of factors influence the piston's speed, including piston diameter and stroke, but these factors are set by the design on a given tool. One way to vary the power of a combustion engine tool is by controlling the fan speed in the combustion chamber, as described in the pending United States patent application serial number 08 / 337,289 , filed on November 10, 1994. A circuit is used to vary the fan speed, and the increasing speed of the fan produces additional power. However, in most conventional combustion engine tools, the piston speed is set by the design. In conventional combustion engine tools, the fixed piston speed prevents an operator from controlling the depth of momentum of the fastener being pushed into a particular type of workpiece or substrate. In addition, depending on the composition of the workpiece or substrate, the lack of speed control can prevent an operator from obtaining a desired consistent depth of momentum. An identical speed of the drive blade, when converted to force applied to a driven fastener within wood, for example, will result in a different depth when applied to a driven fastener inside a steel beam. This speed will result in even another depth when applied to a fastener that is driven into a metal sheet that is fastened to a truss. Therefore, depending on the design of the tool, there may be insufficient power to adequately drive a fastener into all the desired work pieces. An additional problem, limited mainly to tools with extended high speed cylinder, refers to the stability of the tool during operation. The increased stroke of the extended-length combustion tools, used to increase both speed and energy transfer, also increases the delay between combustion and the drive of a fastener into the substrate. This increased delay can reduce the amount of control and applied power of the tool, because the tool recedes in reaction to the combustion, causing the tool nosepiece to move relative to the workpiece before driving the fastener. The disadvantages of this operation are fasteners that are misaligned or impeded. Accordingly, one of the objects of the present invention is to provide an improved combustion engine tool that offers control to the operator for the pulse depth of the fastener. Another object of the present invention is to offer a tool with improved combustion engine, in which the speed of the piston and the blade of the drive can be varied by adjusting the operator of the volume of the displaced air leaving the cylinder. Another object of the present invention is to provide a tool with an improved combustion engine, in which the objective holder remains fixed after combustion until the impact of the blade of the drive with the fastener. A further object of the present invention is to offer an improved extended stroke combustion engine tool, having a nosepiece that is mechanically isolated from the remaining portions of the tool, and which remains fixed up to the impact of the drive blade. with a bra. COMPENDIUM OF THE INVENTION The aforementioned objectives are met or exceeded by the current fastener tool with improved combustion engine, which allows adjustment of the effective size of the outlet port through which the volume of air displaced from the cylinder exits as it exits. the piston and the drive blade advance down the cylinder to impact with a fastener. One or more output ports are supplied near the end of the cylinder terminal. An output port adjustment ring limits the cylinder and has openings corresponding to the output ports. In a first position, the openings are aligned with the output ports in such a way that the output ports are fully exposed. The rotational adjustment of the ring to the other positions will cause the portions of the ring to partially block the exit ports, thereby reducing their effective size. As the effective size of the output ports is reduced, the flow resistance of the displacement volume outside the cylinder increases, and a corresponding increase in the resistance to piston travel towards the terminal end of the chamber of the piston is created. piston. Therefore, the piston speed and the subsequent applied impact force can be reduced incrementally by successfully reducing the effective size of the exit ports through the adjustment of the ring. More specifically, the present invention offers a combustion engine tool that features a self-contained internal combustion energy source, constructed and arranged to create a combustion event to drive a drive blade to impact with a fastener and push it inside. of a piece of work. The tool includes a frame that has a main chamber containing the power source, and a cylinder inside the main chamber that contains a piston to drive the blade of the drive along the length of the cylinder. The advance of the piston displaces an air displacement volume disposed in the cylinder on one side of the piston. The tool also includes at least one displacement volume outlet port disposed in the cylinder to allow the displacement volume to exit the cylinder as it is displaced by the advancing piston, and has an adjustment device for adjusting the resistance in the output of the displacement volume from the cylinder, through at least one output port. In accordance with another feature of the present invention, the nosepiece that guides the blade of the drive to impact with the fastener remains in position against the workpiece after combustion and until the fastener is impacted, even when used a cylinder of extended length. The nosepiece is mechanically isolated in the piston chamber and the remaining portions of the tool. A preferred structure for effecting mechanical isolation is at least one spring. One or more springs disposed between the nosepiece and the remaining portions of the tool absorb the recoil of the tool that is presented in response to the combustion that drives the piston. Although combustion can cause the rest of the tool to move relative to the fastener and the workpiece or substrate, the spring separates the lens holder from the movement in such a way that the lens holder remains fixed with respect to the holder and the substrate until impact. BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a side view of a combustion holder tool with extended stroke according to the present invention, with the portions shown in a partial cross section; FIGURE 2 is an exploded side fragmentary view showing the end portion of the nosepiece of the tool of FIGURE 1; FIGURES 3-7 are schematic sectional views showing the relationship between the output ports of the displacement volume and an output port adjustment ring in different states of rotation of the output port adjustment ring; and FIGURES 8 and 9 are side views assembled from the portion of the tool shown in FIGURE 2, at different times of the operation of the tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2, the preferred embodiment of a high speed, extended length combustion fastener tool, suitable for practicing the present invention, is generally referred to as FIG. A main frame 12 of the tool 10 contains a self-contained internal power source 16. The power source includes a combustion chamber 20 communicating with a cylinder 22. A piston 24, including the discharging gas breakers 26, is positioned inside the cylinder 22 and is connected to a blade of the drive 28. In the preferred embodiment, the cylinder 22 is of extended length type and as such, is considerably larger than the blade of the drive 28. Under the circuit breakers 26, a peripheral bottom flange of the piston 24 includes at least one piston ring (not shown) to create a seal with internal walls of the piston chamber 22. Through the depression of a trigger 30, an operator induces the combustion of a measured amount of propellant, such as, for example, MAPP gas, within the combustion chamber 20. In response, the piston 24 is urged toward an end of terminal 32 of cylinder 22. As piston 24 approaches the end of terminal 32, the driver blade 28 will be guided within a nosepiece 34 and will impact with a fastener ( not shown) placed on a work piece through the lens holder. Although it is contemplated that the present tool will be used with a variety of fasteners, it is preferred that the fastener be of the so-called pin type, described in more detail in U.S. Patent No. 5,199,625, which is incorporated by reference. The impact of the drive blade 28 drives the fastener into a workpiece or substrate. As a safety feature, and to regulate the use of fuel, the discharge of the tool will not occur unless the objective holder 34 is pressed against the workpiece. This positioning causes a link rod 35 to be pushed upward, which moves a valve sleeve (not shown) to seal the combustion chamber 20. Details concerning the sealing of the combustion chamber 20, and related mechanisms can be found in the previously mentioned Nikolich patents, which are incorporated by reference. A volume of displaced air V is defined inside the cylinder 22, and below a lower side 27 of the piston 24. After the ignition of the fuel in the combustion chamber 20 the air in volume V is driven downwardly of the piston 22 and towards out through the exit ports of the displacement volume 40 and through the discharge ports 41 by advancing the piston 24 towards the terminal end 32 of the cylinder 22. A damper 42 defines the end of the stroke of the piston 24 towards the end of the terminal 32. The discharge ports 41 are exposed to the outside under the control of a tongue valve (not shown) or other suitable valve type, located on a port 44. When the piston 24 reaches the end of the terminal 32 , the discharge gas from the combustion chamber 16 flows through the piston towards the circuit breakers 26 in the piston and through the discharge ports 41., which are located on the piston 24 in its position at the end of the terminal. In the same way, once the piston 24 reaches the bottom of its stroke, the displacement volume V will have exited through either of the exit ports 40, which are located below the end of the terminal 32, or through of the discharge ports 41. The displacement volume V can only exit the discharge ports 41 before the piston passes the ports 41 as it advances towards the end of the terminal 32. Any remaining discharge gas remaining behind of the piston 24 (on the combustion side) will then come out through the tab valve due to its higher temperature and pressure. As the gas in the combustion chamber cools, the tab valve closes, and the volume of the gas decreases, creating a vacuum in the combustion chamber that drives the piston 24 back to its starting position. The return of the piston 24 near the combustion chamber 20 places the tool 10 in a position ready for another discharge, and the additional fasteners fed into the objective holder 34 from a tubular magazine 46 can be driven in an identical manner. The tool 10 illustrated in FIGURE 1 is an embodiment of a so-called extended length cylinder. The extended length cylinder 22 allows an operator to stand generally to operate the tool 10 in order to drive the fasteners to the floor level. An important additional feature of the extended length tool 10 is the increase in the stroke of the piston 24. Through the increased stroke, the piston speed during impact and the efficiency of the energy transfer increase, when compared with a tool with identical combustion engine that has a smaller stroke. For example, a standard tool with extended cylinder commercially available at ITW-Paslode of Lincolnshire, Illinois, has a career of approximately 3.5 inches. The volume of the combustion chamber is approximately 16 cubic inches. From an available of approximately 120 joules of energy available during combustion, this tool imparts approximately 41.7% (approximately 50 joules) to a fastener. By keeping all other factors identical, an extended cylinder tool with a stroke of approximately 7 inches imparts approximately 83.3% of the 120 joules available to a fastener. The extended stroke length allows the piston 24 and the associated drive blade 28 to achieve a higher speed and a higher percentage of acceleration before impact with the fastener, than those available with conventional combustion engine tools. " with standard length cylinder ". By lengthening the piston stroke, combustion engine tools can currently achieve drive blade speeds that are comparable to those of PAT tools, which usually have high pressure and a higher drive blade speed .
The cylinder 22 in the tool of extended length has a length that exceeds that of the blade of the drive 28. To keep the blade 28 generally centered during travel, at least two vertically extended stabilization members 47 of the piston 24 they make contact with the inner wall of the piston chamber 22. However, the efficiency of the energy transfer and the piston speed in a given standard tool or in a tool with extended cylinder, is fixed by the design. Between two different combustion engine tools, the stroke can be different and the separate tools could in this way develop different piston speed and energy transfer efficiency. Similarly, alternating the diameter of the piston, the weight of the piston, the volume of the combustion chamber, and the pressure of the initial combustion chamber between two tool designs, could alter the speed and the transfer of energy between the tools . In conventional tools, the fixed nature of the aforementioned parameters prevents an operator from adjusting the drive depth of a fastener. The speed of the piston 24 and the blade of the drive 28 affect the depth of drive, but conventional tools do not offer the adjustment of the speed. An operator using a tool such as those mentioned does not have the ability to control the driving depth, which can result in excessive or poor drive of the fasteners. In addition, when moving from a particular type of substrate, such as concrete, to another, such as steel, the use of a commercially available combustion engine tool can result in inconsistent drive depth. For these and for similar reasons apparent to those skilled in the art, a tool with adjustable piston speed could advantageously allow control of the drive depth of a fastener. By providing an adjustable control of the speed of the piston, the tool 10 of the present invention includes a ring for adjusting the size of the outlet port 48 (best shown in FIGURE 2). In the illustrated embodiment, the adjusting ring 48 fits over an outer jacket 50. The jacket 50 is adhered in an adjusted manner to an outer surface 54 of the cylinder 22, and includes holes spaced in a circumferential shape 52 corresponding to the output ports 40. Similarly, the circumferentially spaced outlet port openings 56 disposed between the solid portions 58 of the adjusting ring 48 can be aligned with both the exit ports 40 and the ports 52. In the In a preferred embodiment, the adjusting ring is plated to provide a positive grip surface. Referring now to FIGS. 2-7, modification of the effective size of the exit ports 40 can be accomplished through the rotary adjustment of the adjustment ring 48. To facilitate this adjustment, the adjustment ring 48 includes a plurality of laterally spaced positioning holes 60 configured and arranged to engage through a short pin 62, which extends radially from an outer surface of the sleeve 50. Each of the separate positioning holes 60 represents a rotational position other than the ring of adjustment 48. One of the positioning holes 60 can align the openings of the exit port 56 exactly with the exit ports 40. In this position, (best shown in FIGURE 3) the exit ports 40 will be fully exposed, and the effective size of the output ports 40 is at the maximum point. The maximum speed of the piston, and the depth of drive of the fastener are achieved when the effective size of the output ports 40 is maximized. In this condition, the flow of the displaced volume of air or gas V which is compressed and pushed downwardly by the piston 24 as it approaches the end of the terminal 32, is subject to the lower resistance. Accordingly, resistance to piston movement or back pressure caused by displacement volume V is also at a minimum. The reduction of the effective size of the exit ports 40 through the rotation of the adjusting ring 48, provides a more restricted path for the flow of the displacement volume, and increases the resistance to the travel of the piston toward the end of the terminal 32. Through successive reductions in the effective size of the exit port, an operator can realize the successive reductions in the depth of drive on a given substrate. Additionally, the consistent drive depth of the fasteners in different types of substrates, such as wood and steel, can be obtained through altering the effective size of the exit ports 40. The successive reductions in the effective size of the ports of output 40 are illustrated schematically in FIGS. 4-7. As the adjusting ring 48 moves in a counter-clockwise manner, successive reductions in the effective size of the output port are obtained through different degrees of alignment of the solid portions 58 of the adjusting ring. 48 with the exit ports 40. In each of FIGURES 4-7, the solid portions 58 progressively cover, to an increasing degree, the exit ports 40. Each reduction in the effective size of the exit port further restricts the way for the displacement volume flow V outwardly through the output ports 40. Each reduction in the exposure of the output ports 40 reduces the effective size of the output ports, and serves to reduce the speed of the piston. In FIGURE 7, the output ports 40 are essentially closed and thus provide the maximum reduction in the speed of the piston. In the illustrated embodiment, the adjustment ring 48 achieves the reduction of the effective size of the exit port. It is contemplated that other mechanical structures for successively restraining the flow path of the displacement volume from the exit ports 40 according to the present invention, are apparent to trained technicians. Referring now to FIGURES 2 and 8-9, a further feature of the invention relates to maintaining the stability of the tool 10 with respect to a workpiece or substrate until the blade of the drive mechanism 28 impacts with a fastener . If the tool moves with respect to the workpiece or the substrate before impact, the transfer of energy to the fastener, and the contact angle between the objective holder 34 and the fastener may be adversely affected. It can be especially difficult to maintain stability in extended length cylinder tools. In these tools, the piston 24 takes longer to travel to the end of the terminal 32, as compared to a tool with a shorter cylinder, and the recoil of the tool 10 in response to combustion can occur before the The piston has completed its travel, and before the blade of the drive 28 impacts with the fastener. During combustion, the released energy pushes the piston 24 down and the tool upwards. In the "standard length" combustion engine tools, this reaction is not perceived by the user due to the greater mass of the tool in relation to the force of the impact. However, in an extended length tool, the time between combustion and the impact of the fastener is large enough to be noticed, and will move the tool up approximately V by the time the drive blade 28 hits. the pin. As discussed above, the largest length of the cylinder 24 in the present tool 10 allows the blade of the drive 28 to achieve, despite being in a longer period of time, a speed comparable to the speeds achieved by the competitive tools PAT, with pressure higher and higher percentages of acceleration. By focusing on this stability problem, the objective holder 34 that positions and holds the fasteners is mechanically isolated against retraction of the remaining portions of the tool 10. At least one, and preferably a plurality of spring 64, allows the cylinder 24 to move in Independently of the lens holder 34 within a limited range, while the lens holder remains stable. Each spring 64 is retained around a vertical ring 65 in the objective holder 34. The adjusting screws 66 connect the cylinder lock 68 with the sleeve 50 in such a way that the cylinder seal will move with the sleeve 50 and the cylinder 24. The shock absorber 42 is threaded into a nipple 69 of the nosepiece 64, with a flange 70 of the shock absorber pressing against a flange 72 of the cylinder closure 68. Movement of the cylinder 24 towards the nosepiece 34 will compress the springs 64 as the closure of the cylinder 68 exerts force on the springs 64. However, the obturator 42 and the objective holder 34 are mechanically isolated from this movement by the springs 64 and remain stable. Advantageously, the insulation serves to maintain the objective holder 34 and the shock absorber 64 stable, even if the remaining portions of the tool 10 undergo a setback in combustion before the impact of a driver blade 28 with a fastener. This aspect of the invention is further illustrated in FIGURES 8 and 9. In FIGURE 8, the cylinder closure compresses the springs 64 in response to the pressure applied by the operator in the alignment of the tool 10 for unloading. In this position, the rim 72 moves downward and separates from the flange 70. The objective holder 34 and the obturator 42 remain fixed as the springs 64 are compressed. In FIGURE 9, the situation after combustion is indicated. Due to the recoil generated by the combustion, the springs 64 decompress, pushing the cylinder 22 and the components attached upwards. While the springs 64 relax, the driver blade 28 has time to impact with a fastener. The upward movement of the cylinder is terminated by the engagement of the flange 72 against the flange 70. In this way, the objective holder 34 and the obturator 42 remain fixed against the workpiece even during combustion. In this way, the blade of the drive mechanism 28 has sufficient time to make its downward travel of the cylinder, to make an impact with the fastener and to propel precisely into the workpiece. As described above with reference to the illustrations, the features of the present invention provide the user with controlled adjustments of the piston speed, as well as mechanical isolation of the tool nose to increase the accuracy of the fastener placement. While a particular embodiment of the objective stabilizer and speed control system for a combustion engine tool of a fastener of the invention has been shown and described, those skilled in the art will appreciate the changes and modifications made to the invention. may be carried out to the present without departing from the invention in its broader aspects and in accordance with the stipulations of the following claims.