Patent Description:
The technology disclosed herein relates generally to linear fastener driving tools and, more particularly, is directed to portable tools that drive staples, nails, or other linearly driven fasteners. At least one embodiment is disclosed as a 'main' pressurized storage chamber (the 'pressure chamber') that is used in a linear fastener driving tool, in which a working cylinder that becomes filled with compressed gas is used to quickly force a piston through a driving stroke movement through the working cylinder, while also driving a fastener into a workpiece. The working cylinder is in fluidic communication (via an end cap) with the pressure chamber which holds most of the compressed gas that is used to "fire" the piston. A fill valve is provided in a side portion of the end cap, which is fastened to the top portion of the pressure chamber. The end cap also covers the top region of the working cylinder.

The fill valve is designed to allow a user to safely refill (or bleed off) the pressurized gas into (or from) the combination pressure chamber and working cylinder. This fill valve is fastened into place near the very top portion of the end cap, but off to the side, so that it does not physically interfere with the working cylinder. The fill valve has an outer cover that can be easily removed by a human user, to quickly obtain access to that fill valve without disassembling any portion of the tool's outer casing. Once the fill valve cover is removed, the threads that held it in place become exposed. A human user can easily attach a refill adapter subassembly to those exposed threads (at the fill valve cover's former location). Once the refill adapter subassembly is attached, pressurized gas can be forced through a hose on the refill adapter subassembly from a gas pressure source, through the fill valve in the end cap, and then into an interior chamber that is formed by the end cap's structure. From that location, the pressurized gas can further travel into the pressure chamber and into the working cylinder.

The preferred fill valve is a Schrader valve, which also allows the human user to bleed out some of the pressurized gas, if desired. The 'output side' of the fill valve is in fluidic communication with a relatively small gas passageway that leads to the interior chamber that is in fluidic communication with the 'main' pressure chamber of the tool. That interior chamber is also in fluidic communication with another gas passageway (at the top) that leads to the displacement volume of the working cylinder. Therefore, when the tool is fully assembled, the main pressure chamber, the interior chamber, the 'top' gas passageway, and the working cylinder displacement volume are all in fluidic communication.

Another feature of the end cap is that it can be removed by a human user to obtain access to the interior parts of the working cylinder, if desired for repair, or for replacement of worn or broken parts. When in use with the tool, the removable end cap is attached to the outer wall of the pressure chamber by multiple threaded screws, and the shapes of the end cap with its large O-ring seal, allows the pressurized gas to begin to safely escape while those screws are being loosened. By the time the final screw is loosened to the point where the end cap can be physically removed from the pressure chamber outer wall, the majority of the pressurized gas will have been reduced to a safe pressure magnitude, so that the human user is not in danger of having any portions of the tool 'explode' in his face by a sudden unsafe discharge of that gas.

Many conventional fastener driving tools use a piston to move a driver blade that forces a nail or staple into a target workpiece, as part of their operational cycle. These pistons are typically driven by compressed air, or in some cases, by combustion air. In a product line of pressurized air tools known as FUSION® that are sold by Senco, pressurized air is stored in a main storage chamber and that air is not vented to atmosphere, but instead is re-used multiple times, and can drive multiple driving strokes (including operational cycle counts in the thousands, per charge of pressurized air).

An early air spring fastener driving tool is disclosed in <CIT>. The Sollberger patent used a rack and pinion-type gear to "jack" the piston back to its driving position. A separate motor was to be attached to a belt that was worn by the user; a separate flexible mechanical cable was used to take the motor's mechanical output to the driving tool pinion gear, through a drive train.

Another air spring fastener driving tool is disclosed in <CIT>. This Kondo patent used a separate air replenishing supply tank with an air replenishing piston to refresh the pressurized air needed to drive a piston that in turn drove a fastener into an object.

One of the Senco FUSION nailer tools known in the prior art is generally designated by the reference numeral <NUM> on <FIG>. As noted above, this tool is sold by Kyocera Senco Industrial Tools, Inc. under the trademark FUSION. This is the original embodiment of the FUSION tool, and the more recent versions do not look exactly like what is depicted on <FIG>; however, the newer versions of the FUSION tool include the same basic parts that work on the same basic principles.

The nailer tool <NUM> includes a pressurized chamber portion <NUM>, an exit end (where the nails are shot) <NUM>, a fastener magazine portion <NUM>, and a hand-operated trigger <NUM>. This is a partial cutaway view, so many of the internal components are visible. This tool has no fill valve.

Another air spring fastener driving tool is disclosed in published patent application No. <CIT>, which uses a rack and pinion to move the piston back to its driving position. The rack and the pinion gear are decoupled during the drive stroke, and a sensor is used to detect this decoupling. The Pedicini tool is disclosed as having a "release valve" to replenish the air that is lost between nail drives.

This Pedicini disclosure places the air refill valve at the very back (or "top") of the working cylinder that drives the blade that shoots the nail. The actual physical structure of such a refill valve is not illustrated in the drawings of Pedicini, however, it clearly shows the valve is to be placed in the center of the back (or top) portion of the working cylinder. Note that, in most nail driving guns, the orientation of the tool has the nail outputting portion of the tool aimed toward the bottom, so that the nail is being shot in a downward, more or less vertical direction. Therefore, the "top" of the tool is essentially the same thing as the back or rear portion of the working cylinder, as illustrated in Pedicini <FIG>.

Kyocera Senco Industrial Tools, Inc. ("Senco") sells a product line of automatic power tools referred to as nailers, including tools that combine the power and the utility of a pneumatic tool with the convenience of a cordless tool. One primary feature of such tools is that they use pressurized air to drive a piston that shoots the nail. In some Senco tools, that pressurized air is re-used, over and over, so there is no need for any compressed air hose, or for a combustion chamber that would require fuel.

Although Senco "air tools" are quite reliable and typically can endure thousands of shooting cycles without any significant maintenance, they do have wear characteristics for certain components. For example, after thousands of operations, the gas pressure inside the pressure chamber can slowly leak down to a pressure level that will need to be increased, or the tool will begin to fail to drive the fasteners successfully into their target workpiece. When that occurs, additional pressurized gas should be added into the pressure chamber. Moreover, if an "air tool" undergoes a mechanical failure (such as a jam), then the tool will need to be disassembled-that requires the pressurized gas to be bled off from the pressure chamber.

In the past, a Senco "air tool" that needed to be replenished with pressurized gas had to be sent to a Senco regional service center. The procedure to refill the tool with additional pressurized gas was not one that a normal user could perform. Special fixtures were required, and furthermore, this type of tool can cause an injury if the user ignores warnings and chooses to improperly service the pressure chamber. The gas pressure is still quite high, even if it has been reduced to an ineffective pressure level for driving nails; it could still injure someone if they tried to "open" the tool without the special fixtures.

Various types of "air tools" have been manufactured and sold over the years that use external air fittings that are connected by hoses to sources of compressed air to provide the power necessary to drive the piston of the fastener driving tool. In many of those "air tool" designs, the compressed air attachment points were fittings that were external to the air tool's overall shape and thereby increased the dimensions. This may not have been much of a disadvantage in air tools that have long air hoses connected to the tool for their normal operations, because the air hoses themselves were always going to be in the way of any movements by the human user of that air tool. However, in the line of tools sold by Senco known as FUSION™, this type of "air tool" has no external hoses or fittings, and therefore, a refill valve mechanism that extended outward from the tool would truly be somewhat of an impediment for the movements of the tool when handled by a user. Therefore, care should be taken when providing a gas refill valve mechanism, so that the tool does not become significantly larger in size and potentially awkward for handling by the user.

In some ways, the FUSION type of "gas-spring tool" has matured to a certain extent, and it has been determined by more than one manufacturer of such tools that a gas refill valve is desirable, mainly because these tools are quite reliable, and typically undergo thousands upon thousands of operating cycles. Only after many such thousands of cycles will some internal parts begin to wear, and only then would you see a typical slight gas leak out of the storage chamber and working cylinder combination, and in that circumstance, an additional charge of pressurized gas into those chambers would be desirable.

Another possibility is that the tool can become damaged, particularly when a fastener such as a nail becomes jammed while being driven by the driver blade, and in that situation, the tool may need to be opened to repair or replace the internal parts; or as a minimum, it needs to have the jammed nail removed from the driver track so that the tool can be continued to be used by a human operator. There are newer patent applications that disclose use of refill valves that are also used as "release" valves so that the pressurized gas inside the working cylinder and/or pressurized storage chamber can be discharged through such a release valve, and thereby make it safe to open the tool for repair, when that action may become necessary.

One example of this type of patent disclosure is a published patent application Number <CIT>. This Wyler published application discloses a fill valve <NUM> that is illustrated in <FIG>. The fill valve is mounted to a square footpad metal base (or "footer") that protrudes from the side of the cylindrical pressure chamber, about half-way between the guide body and the top of the pressure chamber. The placement of the fill valve <NUM> is important, because it is contained within a hollow space of the tool's handle, and in that manner the fill valve is not in the way of any hand movements of the human operator when using the tool. On the other hand, the fact that the fill valve is inside the tool's handle means that the casing of the tool must be at least partially disassembled before access to the fill valve is possible.

Another gas spring fastener driving tool with a fill valve is disclosed in published application number <CIT>, owned by Hitachi Koki Company, Ltd. In Komazaki, the fill valve is referred to as an "intake valve" at reference numeral <NUM>, and it is positioned at the very top of the pneumatic chamber, much like that disclosed in Pedicini, discussed above. Moreover, the Komazaki intake valve is just that: it can be used only for placing additional pressurized gas into the pneumatic chamber, because it is a one-way check valve, and even has some type of switch lever to open the air passageway, or to keep it closed. If pressurized gas is to be released from this tool, then a separate "relief" valve <NUM> is added to the top of the tool, as illustrated in FIG.

Yet another gas spring fastener driving tool with a fill valve is disclosed in published application number <CIT>. This published application illustrates a "filling valve" at reference numeral <NUM> on <FIG>, and is mounted to a bottom wall of the pressurized gas chamber. This filling valve <NUM> is also a single-direction gas valve, because the same figure shows a second "relief valve" <NUM> that is to be operated to discharge the gas within the compression chamber. Both of these valves are mounted on the bottom wall of the main storage pressure chamber. Yet a further gas spring fastener driving tool with a fill valve is disclosed in published application number <CIT>. In Pomeroy, Figs. 1A-<NUM> illustrate a gas spring-powered fastener driver <NUM> operable to drive fasteners (e.g., nails, tacks, staples, etc.) into a workpiece. The fastener driver <NUM> includes a gas cylinder assembly <NUM> removably coupled to a mounting plate <NUM> of an internal frame structure <NUM> (i.e., housing). The gas cylinder assembly <NUM> includes an inner piston cylinder <NUM> and a moveable piston <NUM> positioned within the inner cylinder <NUM>. The fastener driver <NUM> does not require an external source of air pressure, but rather the gas cylinder assembly <NUM> further includes an outer cylinder <NUM> containing pressurized gas (e.g., air) in fluid communication with the inner cylinder <NUM>. The driver further comprises a cylinder spacing member <NUM> comprising an opening that allows for fluid communication between the piston bore <NUM> and the gas storage chamber <NUM> formed by outer cylinder <NUM>. A fill valve is depicted at reference numeral <NUM> on <FIG>, and is coupled to a rear wall <NUM> of outer cylinder <NUM>. Pomeroy's fill valve <NUM> is shown positioned directly above a piston <NUM> and a driver blade <NUM>, and the fill valve <NUM> is in direct pneumatic communication with outer cylinder <NUM>.

Accordingly, it is an advantage of the present technology disclosed herein to provide a fastener driving tool that operates on a gas spring principle, in which the pressure chamber includes a refill valve subassembly positioned near the top of the tool.

It is another advantage of the present technology to provide a fastener driving tool that operates on a gas spring principle and provides a refill valve subassembly that is permanently mounted to an end cap that itself is fastened to a main pressurized storage chamber, and provides a refill valve subassembly that is permanently mounted to an end cap that itself is fastened to a main pressurized storage chamber, using a set of fasteners that can be released in a controlled manner so as to allow the pressurized gas inside the main storage chamber to be safely released before obtaining access to the interior portion of the working cylinder of the tool.

It is a further advantage of the present technology to provide a fastener driving tool that operates on a gas spring principle, in which the tool includes an end cap that is fastened to a main pressurized storage chamber using a set of fasteners that can be loosened in a controlled manner so as to release the internal gas pressure in a controlled manner that is safe for a normal human user without special fixtures, and thereby enabling that user to access the internal portions of the tool for repair or for replacement of worn parts, for example.

It is yet another advantage of the present technology to provide a fastener driving tool that operates on a gas spring principle, in which the tool includes a refill valve subassembly that is positioned alongside of the working cylinder and within an end cap that covers a distal end of the working cylinder, and in which the refill valve has a connecting passageway to an interior chamber of the end cap that is in fluidic communication with a main pressurized storage chamber and also is in fluidic communication with a displacement volume of the working cylinder.

It is a yet further advantage of the present technology to provide a fastener driving tool that operates on a gas spring principle, in which the tool includes a refill valve subassembly that is positioned in an end cap near the top of the tool, and wherein the refill valve is covered by a valve cover that is easily removable by a human operator to obtain quick access to the refill valve, without having to disassemble any portion of the enclosure or housing of the tool.

It is still a further advantage of the present technology to provide a fastener driving tool that operates on a gas spring principle, in which the tool includes a refill valve subassembly in which the refill valve can act both as a "fill valve" and as a "release valve," so that the pressurized gas within the main storage chamber and within the end cap interior chamber and the displacement volume of the working cylinder can be easily reduced in pressure, for example, after a filling operation has occurred, in which that filling operation has somewhat overpressurized the interior portions of the tool, including the pressurized gas chamber.

It is still a further advantage of the present technology to provide a fastener driving tool that operates on a gas spring principle, in which the tool includes a refill valve subassembly that is able to receive a relatively quick connect and disconnect refill adapter subassembly and nozzle.

Additional advantages and other novel features will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the technology disclosed herein.

To achieve the foregoing and other advantages, and in accordance with one aspect, a fastener driving tool is provided, which comprises: a working cylinder that includes a movable piston, the cylinder including a variable displacement volume on a first side of the piston, and the cylinder including a variable venting volume on a second, opposite side of the piston; a storage chamber; an end cap that is attached to at least one of the cylinder and the storage chamber near an end portion of the fastener driving tool, the end cap including at least one first gas passageway that is in fluidic communication with the cylinder and with the storage chamber; a movable driver that is in mechanical communication with the piston; a guide body that guides movements of the driver; and a fill valve that is mounted at a side portion of the end cap, the end cap including a second gas passageway that travels between an inner end of the fill valve and the at least one first gas passageway of the end cap; wherein: the variable displacement volume of the cylinder, the storage chamber, and the at least one first gas passageway of the end cap all contain pressurized gases when the fastener driving tool is in use; and the pressurized gases are not vented to atmosphere after a drive stroke, but instead the pressurized gases are re-used for a plurality of operating cycles.

In accordance with another aspect, a method for filling pressurized gas in a fastener driving tool is provided, in which the method comprises the following steps: (a) providing a fastener driving tool that includes: a working cylinder that includes a movable piston, the cylinder including a variable displacement volume on a first side of the piston, and the cylinder including a variable venting volume on a second, opposite side of the piston; a storage chamber; an end cap that is attached to at least one of the cylinder and the storage chamber near an end portion of the fastener driving tool, the end cap including at least one first gas passageway that is in fluidic communication with the cylinder and with the storage chamber; a movable driver that is in mechanical communication with the piston; a guide body that guides movements of the driver; and a fill valve that is mounted at a side portion of the end cap, the end cap including a second gas passageway that travels between an inner end of the fill valve and the at least one first gas passageway of the end cap; (b) attaching a pressurized gas source to an outer end of the fill valve; and (c) pumping pressurized gas through the fill valve, from the pressurized gas source, and thereby filling the storage chamber with additional pressurized gas.

In accordance with yet another aspect, a fastener driving tool is provided, which comprises: means for storing a pressurized gas; valve means for introducing additional pressurized gas into the means for storing a pressurized gas; means for propelling a reciprocating element in a drive stroke using the pressurized gas, wherein the pressurized gas is not vented to atmosphere after the drive stroke, but instead the pressurized gas is re-used for a plurality of operating cycles of the reciprocating element; and means for propelling the reciprocating element in a return stroke, to complete an operating cycle.

Still other advantages will become apparent to those skilled in this art from the following description and drawings wherein there is described and shown a preferred embodiment in one of the best modes contemplated for carrying out the technology. As will be realized, the technology disclosed herein is capable of other different embodiments, and its several details are capable of modification in various, obvious aspects all without departing from its principles. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the technology disclosed herein, and together with the description and claims serve to explain the principles of the technology. In the drawings:.

Reference will now be made in detail to the present preferred embodiment, an example of which is illustrated in the accompanying drawings, wherein like numerals indicate the same elements throughout the views.

It is to be understood that the technology disclosed herein is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The technology disclosed herein is capable of other embodiments and of being practiced or of being carried out in various ways. Unless limited otherwise, the terms "connected," "coupled," or "mounted," and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, or mountings. In addition, the terms "connected" or "coupled" and variations thereof are not restricted to physical or mechanical connections or couplings. Furthermore, the terms "communicating with" or "in communications with" refer to two different physical or virtual elements that somehow pass signals or information between each other, whether that transfer of signals or information is direct or whether there are additional physical or virtual elements therebetween that are also involved in that passing of signals or information. Moreover, the term "in communication with" can also refer to a mechanical, hydraulic, or pneumatic system in which one end (a "first end") of the "communication" may be the "cause" of a certain impetus to occur (such as a mechanical movement, or a hydraulic or pneumatic change of state) and the other end (a "second end") of the "communication" may receive the "effect" of that movement/change of state, whether there are intermediate components between the "first end" and the "second end," or not. If a product has moving parts that rely on magnetic fields, or somehow detects a change in a magnetic field, or if data is passed from one electronic device to another by use of a magnetic field, then one could refer to those situations as items that are "in magnetic communication with" each other, in which one end of the "communication" may induce a magnetic field, and the other end may receive that magnetic field, and be acted on (or otherwise affected) by that magnetic field.

The terms "first" or "second" preceding an element name, e.g., first inlet, second inlet, etc., are used for identification purposes to distinguish between similar or related elements, results or concepts, and are not intended to necessarily imply order, nor are the terms "first" or "second" intended to preclude the inclusion of additional similar or related elements, results or concepts, unless otherwise indicated.

In addition, it should be understood that embodiments disclosed herein include both hardware and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware.

However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the technology disclosed herein may be implemented in software. As such, it should be noted that a plurality of hardware and software-based devices, as well as a plurality of different structural components may be utilized to implement the technology disclosed herein. Furthermore, if software is utilized, then the processing circuit that executes such software can be of a general purpose computer, while fulfilling all the functions that otherwise might be executed by a special purpose computer that could be designed for specifically implementing this technology.

It will be understood that the term "circuit" as used herein can represent an actual electronic circuit, such as an integrated circuit chip (or a portion thereof), or it can represent a function that is performed by a processing circuit, such as a microprocessor or an ASIC that includes a logic state machine or another form of processing element (including a sequential processing circuit). A specific type of circuit could be an analog circuit or a digital circuit of some type, although such a circuit possibly could be implemented in software by a logic state machine or a sequential processor. In other words, if a processing circuit is used to perform a desired function used in the technology disclosed herein (such as a demodulation function), then there might not be a specific "circuit" that could be called a "demodulation circuit;" however, there would be a demodulation "function" that is performed by the software. All of these possibilities are contemplated by the inventors, and are within the principles of the technology when discussing a "circuit.

Referring now to <FIG>, a new embodiment of a FUSION-type tool is illustrated. The pressurized chamber subassembly is shown from the side in a cross-section view, and is generally designated by the reference numeral <NUM>. The outer sleeve or wall of the pressure chamber is illustrated at <NUM>, and the top portion of the pressure chamber is covered by an end cap subassembly, designated by the reference numeral <NUM>. There is a similar cross-section view illustrated in <FIG> that shows fewer components, and both of these cross-section views are taken along the section line <NUM>-<NUM> on <FIG>.

Referring now to <FIG>, a movable piston is illustrated as being within a working cylinder, in which the outer cylindrical wall of the working cylinder is designated at <NUM>. In this embodiment, the piston is provided as two separate parts, in which the top portion of the piston at <NUM> is made of a non-metallic material, such as Delrin, and the bottom portion of the piston at <NUM> is made of a metallic material, such as aluminum. In this embodiment the two piston halves are threaded together along threads <NUM> into a single reciprocating subassembly, which are external threads for the bottom of the piston (the aluminum portion), and are internal threads for the upper non-metallic portion <NUM>. It will be understood that the exact shape and construction of such a reciprocating piston can be quite different while still remaining within the principles of this technology being disclosed herein.

The upper piston portion <NUM> includes some outer channels in its cylindrical outer surface so that an annular piece of foam containing lubricant can be positioned within that upper channel, in this case the upper foam at <NUM>. The next groove in the piston contains a quad-seal at <NUM>. The next lower groove in the outer portion of the piston contains another annular piece of foam at <NUM>, which can either contain lubricant or not have lubricant. The choice of with, or without, lubricant for the lower foam piece <NUM> is up to the system designer of the entire tool.

On <FIG>, the piston subassembly is illustrated at a mid-position, and it can reciprocatingly move farther up (in this view) towards the end cap <NUM>, or can move farther down (in this view) toward a piston stop <NUM>. (The piston stop is also referred to as a bumper. ) The variable volume "above" the piston in this view (at reference numeral <NUM>) is referred to as the "displacement volume" which is pressurized, whereas the volume "below" the piston in this view (at reference numeral <NUM>) is a variable volume referred to as "venting chamber" volume, which is open to atmosphere at a lower portion of the tool. As is understood in this area of technology, as the piston moves up and down in a reciprocating fashion, the displacement volume decreases and increases with each up and down stroke, and the venting chamber volume below the piston correspondingly also increases and decreases as the piston moves up and down. The overall internal working cylinder volume is referred to by the reference numeral <NUM> on <FIG>, which is essentially a combination of the displacement volume and the variable venting chamber volume, and further includes the volume that the piston would normally take. As can be seen in <FIG>, there is no piston, so the working cylinder open volume at <NUM> is completely empty, which is for illustrative purposes only. As can be understood, in the illustrated design, this overall internal working volume <NUM> does not vary in size, since the cylinder walls are rigid.

The bottom piston half <NUM> is attached to a driver <NUM> by use of a pair of pins <NUM> and <NUM> that are inserted through small channels, as can be seen in <FIG>, that also extend through openings in the driver. The driver itself goes through an opening of the piston stop <NUM>, and further into a guide body <NUM>, which guides the driver in its movements for driving a fastener. The driver <NUM> is also referred to in many other patents as a hammer or as a blade. In the illustrated embodiment, the driver <NUM> includes a series of openings at <NUM>, which are used for catching against a latch (not shown in this embodiment) that can inhibit the downward movement of the driver at times in which it is inappropriate for the driver to be moving in a downward direction. This aspect of the driver and the latch will not be further described for this embodiment-see the description in connection with <FIG>.

There is a main storage chamber that is pressurized with gas, generally designated by the reference numeral <NUM>, which is also referred to herein as the "pressure chamber. " In this embodiment, the pressure chamber <NUM> comprises an annular space that partially surrounds the working cylinder wall <NUM>, and the pressurized space at <NUM> is essentially between the outer surface of the working cylinder wall <NUM> and the inner surface of the pressure chamber outer wall <NUM>.

The main purpose of the pressure chamber is to hold additional pressurized gas for use in driving the piston subassembly in its downward or "driving stroke" direction, in which it will be driving a fastener such as a nail or a staple. This additional pressurized gas in the pressure chamber allows for a sufficient force to be imparted against the upper surface of the top portion of the piston at <NUM>, while forcing a nail or staple into a target surface, such as a piece of wood. This storage volume <NUM> that represents the pressure chamber allows a lower overall gas pressure to be used in the overall workings of this fastener driving tool to provide a gas spring effect without requiring an extremely high pressure that would otherwise be required in the displacement volume above the piston within the working cylinder, if there was no pressure chamber to hold additional pressurized gas.

Referring now to the exploded view of <FIG>, The end cap subassembly <NUM> includes a metal end cap <NUM>, which is fastened to the uppermost portion of the outer walls of the pressure chamber by fasteners <NUM>. It can be seen that there are several fasteners that hold either the end cap <NUM> or the guide body <NUM> to the pressure chamber outer wall, at a pair of flanges <NUM> and <NUM>. The flanges have extensions (or bosses) with openings in them for holding the fasteners, which in this embodiment are a set of screws or bolts. For example, the flange <NUM> has openings for holding the screws <NUM> that hold the end cap <NUM> in place; similarly, the flange <NUM> has openings for holding the screws <NUM> that hold the guide body in place. On the end cap portion, there are washers <NUM> that are mated with the screws <NUM>, that are helpful for holding the end cap in place, as well as maintaining the internal gas pressure, without leakage.

The end cap <NUM> has a mating flange <NUM> that mounts against the flange <NUM> that is part of the pressure chamber outer wall <NUM>. Similarly, the guide body <NUM> has a mating flange <NUM> that is to be mounted against the flange <NUM> that is on the opposite side of the pressure chamber. The end cap <NUM> also has a circular bottom surface at <NUM> that mates to the similar circular outer surface of the pressure chamber <NUM>, all in the same area as the flanges <NUM> and <NUM>; the details of the structures can be seen on <FIG> and on <FIG>.

As noted above, the portion of the tool that is referred to by the reference numeral <NUM> is the entire working cylinder subassembly, which is under pressure once a pressurized gas is introduced into the system. With that in mind, there are additional seals to help hold that pressure within the combination of the pressure chamber <NUM> and the other portions that contain pressurized gas, including the displacement volume <NUM> and other passageways in the end cap <NUM>. On the end cap subassembly <NUM> of this first embodiment, there are two seals (which are O-rings) at the reference numeral <NUM>, and on the opposite end there are seals (which are O-rings) at the reference numeral <NUM>. The exact placement of these O-rings can be seen in the cross-section view of <FIG>.

Also viewable in <FIG> is a washer <NUM> that sits atop the piston stop <NUM>, and provides some extra cushioning effect with regard to the impact of the metal portion of the piston <NUM>. In addition, the cylinder sleeve wall is thickened and becomes curved into a larger outer diameter at a portion <NUM>, which extends against the inner surface of the pressure chamber outer wall; at this juncture between those two structures is where the O-rings <NUM> are positioned-this again is viewable in <FIG>. Note that the precise number and placement of such seals are up to the tool's designer and, for example, a single seal <NUM> can suffice.

Further details of the end cap <NUM> are viewable on <FIG>. A portion of the working cylinder wall <NUM> extends farther above the pressure chamber and becomes essentially surrounded by the end cap. This portion is designated by the reference numeral <NUM> on <FIG>; however, it should be noted that the structure at <NUM> is merely a portion of the overall cylinder outer wall <NUM>, and has the same dimensions with regard to inner and outer diameters as the rest of the working cylinder (until reaching the portion at <NUM> where the cylinder wall becomes thicker and larger in diameter).

When the tool is assembled, there is a set of passageways within the end cap that allow pressurized gas to flow between the pressure chamber <NUM> and the displacement volume <NUM>. There is an outer gas passageway at the reference numeral <NUM> and an inner gas passageway at the reference numeral <NUM>, and both are within the structure of the end cap <NUM>. The outer gas passageway <NUM> allows pressurized gas to flow between the pressure chamber <NUM> and the inner gas chamber passageway <NUM>; the inner gas passageway <NUM> allows pressurized gas to flow between the outer gas passageway <NUM> and the displacement volume <NUM> of the working cylinder. In the illustrated embodiment, these gas passageways <NUM> and <NUM> are in fluidic communication with both the displacement volume <NUM> and the pressure chamber <NUM> at all times. It should be noted that the gas passageways <NUM> and <NUM> can be referred to herein, either singly or combined together, as "at least one first gas passageway" which is/are in fluidic communication with the "cylinder" (e.g., the displacement volume <NUM>) and/or with the "storage chamber" (e.g., the pressure chamber <NUM>).

The overall shape and structure of the end cap and its mating flange surfaces to the top of the pressure chamber are designed so that a human user can safely remove the end cap merely by loosening the screws <NUM>, even though the working cylinder and the pressure chamber still contain a relatively high gas pressure therewithin. As a human user begins to remove the screws <NUM>, the pressurized gas will safely begin to escape around the edges of the bottom surfaces <NUM> of the end cap, and that gas is essentially released at a controlled rate because of two main factors: in the first place there are the O-ring seals <NUM> (or a single seal), and in the second place it will take some time to remove the screws to even begin to allow gas to start escaping around the perimeter of the outer flange surfaces <NUM> and <NUM>. As the screws are loosened, the pressurized gas will eventually escape, and by the time the final screw is totally removed, the internal gas pressure will be at a safe magnitude, and the end cap can then safely be entirely removed from the top of the pressure chamber <NUM>, thereby exposing the interior of the working cylinder so that the piston and other internal components can be replaced, as desired.

Referring now to <FIG>, the top portion of the end cap <NUM> is seen, in which the four fasteners <NUM> are seated down against the flange surfaces <NUM> of the end cap. These screws are placed in an area where there is sufficient ease of access for removal.

The end cap subassembly <NUM> includes rather more structure than merely the gas passageways <NUM> and <NUM>, and the flanges and the screws for holding the end cap to the pressure chamber. In addition to what has been discussed above, there also is a fill valve subassembly <NUM> (see <FIG>) that includes a fill valve at <NUM>. In the illustrated embodiment, the fill valve <NUM> is a Schrader valve. In the illustrated embodiment, the fill valve <NUM> is threaded into a portion of the end cap along the outer side of the outer gas passageway <NUM>. In this manner, the fill valve only adds a minor amount of extra "territory" or footprint to the end cap itself, and at the same time, the fill valve remains completely outside of the moving parts of the working cylinder. As can be seen in the top view of <FIG>, this fill valve <NUM> really does not add any extra size to the outer surfaces of the tool, except (as can be seen in <FIG>) the fill valve has a higher surface along the top of that side of the end cap, as compared to the opposite side of the end cap outer dimension.

After the fill valve <NUM> has been assembled into the end cap, then a small O-ring <NUM> is installed to a threaded valve cover <NUM>, and they are installed above the fill valve <NUM>. In this manner, the valve cover <NUM> acts as a dust and debris cover to prevent physical damage to the fill valve, and with the O-ring <NUM> acting as a seal, this helps to prevent any gas pressure from seeping out through the fill valve back into the atmosphere from the interior portions of the pressurized chamber and working cylinder.

As can be seen on <FIG> and <FIG>, there is a gas passageway <NUM> that extends from the bottom of the fill valve into the outer gas passageway <NUM> of the end cap. Another way of describing the gas passageway <NUM> is that it travels between an inner end of the fill valve and the outer gas passageway <NUM> of the end cap <NUM>. Note that the fill valve exhibits both an inner end and an outer end; the inner end is in fluidic communication with the gas passageway <NUM>, and the outer end is typically covered by the valve cover <NUM> during normal use of the tool. It should be noted that the gas passageway <NUM> also can be referred to herein as "a second gas passageway" that travels between an "inner end of the fill valve" and "at least one first gas passageway" of the end cap <NUM>.

It can be clearly seen from viewing <FIG> and <FIG> that the side portion of the end cap where the fill valve <NUM> mounts is located at a position that is outside the boundaries of the working cylinder wall <NUM>, and for that matter, its position is also outside the boundaries of the pressure chamber outer wall <NUM> and the gas passageways <NUM> of the end cap. Furthermore, the side portion of the end cap where the fill valve mounts is outside a boundary of an imaginary cylinder that extends through and beyond the working cylinder.

Since the outer passageway <NUM> is in fluidic communication with both the working cylinder displacement volume <NUM> and the pressurized chamber <NUM>, then any additional pressurized gas introduced through the fill valve <NUM> will also end up in those important regions of the gas spring fastener driving tool.

In essence, if the tool has been disassembled by removing the end cap subassembly <NUM>, which will de-pressurize the internal chambers, such as the pressure chamber <NUM> and the displacement volume <NUM>, then after the tool has been repaired (or has otherwise had some worn parts replaced, for example, as preventative maintenance), then the tool must then be somehow re-pressurized. That of course is the main function of the fill valve subassembly <NUM>, and that procedure includes a few additional parts that will be needed to create a refill "system. " For example, there will need to be a source of pressurized gas, some type of hose, and some type of hose connector that will mate to the fill valve <NUM>. Examples of those devices are illustrated on <FIG>, which is discussed below.

In the first place, the fill valve cover <NUM> must be unscrewed, and in the illustrated embodiment, that cover <NUM> has a hexagonal head and can be removed by a standard hex wrench. Once that has been removed, access is now immediately available to the top of the fill valve <NUM>. A "refill adapter subassembly" <NUM> will then be screwed onto the threads above the fill valve <NUM> where the threaded valve cover <NUM> was just removed.

Referring now to <FIG>, the view shows a refill adapter subassembly <NUM>. The refill adapter subassembly <NUM> has a fill valve fitting <NUM> on one end that attaches to the fill valve <NUM> on the tool. Inside the fill valve fitting <NUM> is a fill needle <NUM> (see <FIG>) which is attached to a pressure regulator <NUM>. The pressure regulator <NUM> is attached to a filter <NUM>, which is attached to a hose fitting <NUM> at a distal end from the fill valve fitting <NUM>. The hose fitting <NUM> is coupled to an air or gas source. These parts are temporarily coupled to the refill valve <NUM> when a user desires to add pressurized air (or other gas) into the pressurized chamber <NUM>, and further details of this procedure are provided below.

Referring now to <FIG>, the same components from <FIG> are illustrated in an exploded view, and are used only during a refill procedure. The fill valve fitting <NUM> is used only during a refill procedure, and it screws into the fill valve <NUM>. (The fill valve cover <NUM> first must be unscrewed from the fill valve <NUM>. ) A nozzle <NUM> is then placed into and through the fill valve fitting <NUM>. A blow gun or an air hose (not shown) would be coupled to the hose fitting <NUM>, for use with an external gas pressure source. Once the tool's pressure chamber has reached an appropriate gas pressure, the refill adapter subassembly <NUM> can be removed, by unscrewing the fill valve fitting <NUM>.

It should be noted that, if a standard Schrader valve is used as the fill valve <NUM>, then pressurized gas may not only be introduced into the tool's inner pressurized chambers, but pressurized gas can also be removed from those chambers, if desired. This can be important if the human user puts an excessive amount of pressurized gas into the storage chamber <NUM> during a refill procedure. If that indeed happens, then the human user can take a pressure gauge and measure the internal pressure by accessing the top of the fill valve <NUM>, and if that pressure is excessive, the user can easily press against the plunger of the Schrader valve to release some of that pressurized gas from the internal chambers of the tool. In this way, even though a Schrader valve is a one-way valve and acts like a check valve, it still is readily configurable to allow gas to move in the opposite direction to lower the internal pressure, as desired by the user. In other words, if a Schrader valve is used for the fill valve <NUM> (as discussed above), then that "fill valve" can also be used as a pressure release valve.

Referring now to <FIG>, an earlier embodiment of a Senco nailer tool is generally designated by the reference numeral <NUM>. This tool is sold by Senco under the trademark FUSION. This is the original embodiment of the FUSION tool, and the more recent versions do not look exactly like what is depicted on <FIG>. However, the newer versions of the FUSION tool include the same basic parts that work on the same basic principles, as appropriate for use in the present nailer tool described herein.

The nailer tool <NUM> includes a pressurized chamber portion <NUM>, an exit end (where the nails are shot) <NUM>, a fastener magazine portion <NUM>, and a hand-operated trigger <NUM>. This is a partial cutaway view, so many of the internal components are visible.

Referring now to <FIG>, an alternative embodiment fastener driving tool is depicted, showing a fastener driver portion <NUM> of an older Senco tool design. <FIG> illustrates the mechanisms that will actually drive a fastener into a solid object. This includes a driver <NUM>, with driver teeth <NUM>, a driver track <NUM> along a guide body <NUM>, a rotary-to-linear lifter <NUM> subassembly, and a latch <NUM>. The rotary-to-lifter <NUM> is also sometimes referred to herein simply as a "lifter. " Driver <NUM> is rather elongated, and exhibits multiple protrusions, or "teeth," <NUM> that are positioned along the longitudinal surfaces of the driver. In the illustrated embodiment, these teeth <NUM> are spaced-apart not only in a transverse direction from the elongated centerline of driver <NUM>, but they are also spaced-apart from one another along the outer longitudinal edges of the driver <NUM>. It will be understood that the precise positions for the teeth <NUM> could be different from those illustrated for the driver <NUM> without departing from the principles of the present technology.

There is a cylinder base <NUM> that mainly separates the gas pressure portions of the fastener driver portion <NUM> from the mechanical portions of that driver portion. The venting of air from the cylinder's venting chamber passes through the cylinder base <NUM>. The mechanical portions of <FIG> begin with a rotary-to-linear lifter <NUM> which was briefly mentioned above, along with a lifter drive shaft <NUM>. Drive shaft <NUM> protrudes through the center portions of the fastener driver portion <NUM> and through the center of the lifter <NUM>, and this shaft is used to rotate the lifter, as desired by the tool's control system.

Lifter <NUM> is not designed with an entirely circular outer perimeter, but instead is arcuate and portions of its perimeter exhibit an eccentric shape of a cam. A portion of the lifter's outer perimeter is mainly circular for about half of a circle (designated by the reference numeral <NUM>), but the other half of the lifter's outer perimeter is more eccentric, which provides an elliptical surface that is designated by the reference numeral <NUM>. The rotary-to-linear lifter <NUM> also includes three cylindrical protrusions (or "extensions") that will also be referred to herein as "pins. " The first such pin ("pin <NUM>") is designated <NUM>, the second pin ("pin <NUM>") is designated <NUM>, while the third pin ("pin <NUM>") is designated <NUM>. Furthermore, there is a fourth cylindrical pin ("pin <NUM>") that protrudes from the opposite side of the lifter <NUM>, which fourth pin is designated <NUM>.

It should be noted that <FIG> depicts a "back" side of the first three pins <NUM>, <NUM>, and <NUM>, in which this view essentially shows a "boss portion" of those pins. These boss portions of the pins <NUM>, <NUM>, <NUM> are not entirely necessary for the proper functioning of the rotary-to-linear lifter <NUM>, however, the boss portions are illustrated in the figures of this patent document for ease of description. (In other words, the surface of the lifter <NUM> could be perfectly smooth at those locations rather than exhibiting a "boss. ") It should be understood that the "working side" of these three pins <NUM>, <NUM>, and <NUM> is on the opposite side of the lifter <NUM> in the view of <FIG>. It should also be noted that pins <NUM>, <NUM>, <NUM>, and <NUM> are illustrated as having circular cross-sectional shapes, which is desirable for this embodiment, although other cross-sectional shapes could instead be used without departing from the principles of the present technology, particularly for the fourth pin <NUM>.

The latch <NUM> has a latch shaft <NUM> protruding therethrough, and this shaft rotates the latch <NUM> as determined by the tool's controller. Latch <NUM> includes a latch "catching surface" at <NUM>.

When the rotary-to-linear lifter <NUM> and the latch <NUM> are in their respective positions at the end of a firing (driving) stroke (not shown on <FIG>), the latch <NUM> is rotated so that its latching surface <NUM> is moved to a location that will not interfere with the teeth <NUM> of the driver <NUM>. This is necessary so that the driver <NUM> can make a linear stroke from its top-most position to its bottom-most position. However, the latch <NUM> will later be slightly rotated by the latch shaft <NUM> (which is spring-loaded) so that its catching surface <NUM> will be able to interfere with the teeth <NUM>.

After the fastener driving tool has been used to drive a fastener, the tool now must cause the driver <NUM> to be "lifted" back to its top-most position for a new firing (driving) stroke. This is accomplished by rotating the lifter <NUM>, which is actuated by a motor <NUM>, through its gearbox <NUM>-see <FIG>.

As rotary-to-linear lifter <NUM> rotates, at least one of its pins <NUM>, <NUM>, or <NUM> will come into contact with one of the teeth <NUM> along the left side (as seen in <FIG>) of the driver <NUM>. This will cause the driver to be "lifted" upward (as seen in <FIG>). As the lifter <NUM> rotates, one of the teeth <NUM> will be in contact with one of the rotating pins <NUM>, <NUM>, <NUM> throughout a portion of the rotational travel of the lifter, and the "next" pin will then come into contact with the "next" tooth <NUM> so that the driver <NUM> continues to be moved upward. This will remain true until the eccentric cam surface <NUM> comes into play, and since there are no "working" lifter pins protruding along that surface, the driver <NUM> will not continue to be driven upward while the eccentric cam surface <NUM> is positioned along the right portion (as seen in <FIG>) of the rotary-to-linear lifter <NUM>. However, when this occurs, the latch <NUM>, which is spring-loaded, will have its latch catching surface <NUM> in a proper location to "catch" the closest tooth <NUM> along the right-hand side (as seen in <FIG>) of the driver <NUM>, thereby preventing the driver from falling downward for any significant distance. After this occurs, the "next" lifter pin (which will be the pin <NUM>) will then come along and again make contact with one of the teeth <NUM> along the left-hand side (as seen in <FIG>) of the driver <NUM>, thereby continuing to lift the driver toward the top (as seen in <FIG>) of the cylinder.

In this illustrated embodiment, the rotary-to-linear lifter <NUM> makes two complete rotations to lift the driver <NUM> from its lower "resting" position to its upper "ready" position. At the end of the second rotation, the parts will be configured as illustrated in <FIG>. The piston (not shown in <FIG>) is once again near the top of the cylinder, and the combined volumes of the main storage chamber and displacement volume have now been reduced to a smaller volume, which means their gases are under a greater pressure, since the gas that was above the piston and in the storage chamber was compressed during the lift of the driver. During the lift of the driver, the latch <NUM> was "engaged" with the driver teeth <NUM>, however, in this embodiment the latch has a smooth surface in one direction that allows the teeth <NUM> to push the latch out of the way during the upward lift of the driver. This is much like a ratchet-type action, remembering that the latch is spring-loaded so as to act in this manner.

The "last" tooth <NUM> along the right-hand side (as seen in <FIG>) of the driver <NUM> is engaged with the latch catching surface <NUM>, and so latch <NUM> now prevents the driver from being moved downward (as seen in this view). The third pin <NUM> is still in contact with the lower-most tooth <NUM> along the left-hand side (as seen in <FIG>) of the driver <NUM>, at this point in the rotational travel of the rotary-to-linear lifter <NUM>. There is a sensor which, in the illustrated embodiment, is a limit switch (not shown), that detects the rotational movements of the lifter <NUM>. This sensor detects the rotational position of the fourth pin <NUM>.

When the sensor detects the fourth pin <NUM> a first time (in this embodiment), the control system turns off the solenoid (not shown), which will then allow the latch <NUM> to engage the right-hand teeth (in these views) of the lifter <NUM>. Note that the solenoid can also be turned off earlier during the lift, if desired. When sensor detects this pin <NUM> a second time (in this embodiment), the current to the motor <NUM> is turned off, and the motor thus is deenergized and stops the lifting action of the driver <NUM>. Later in the operating cycle, the solenoid acts as a latch actuator.

Due to the gas pressure above the piston, the driver/piston subassembly will drift downward (in these views) a small distance until the tooth <NUM> contacts the latch surface <NUM>. This is the position illustrated in <FIG> of these components, and this configuration is considered to be the "rest" position of the tool. (It is also the "ready" position of the driver. ) Although the gas pressure in the combined main storage chamber and displacement volume is near its maximum, the latch <NUM> prevents the driver from being moved further downward, so the piston is essentially locked in this position until something else occurs.

When it is time to drive a fastener, the next action in the embodiment of <FIG> is to cause the motor <NUM> to become energized once again. This occurs by two independent actions by the user: the safety contact element of the nose <NUM> (see <FIG>) must be pressed against a solid surface, and the trigger actuator <NUM> must be actuated. When both of these actions properly occur, current is delivered to the motor <NUM> which will once again turn the rotary-to-linear lifter <NUM>. Also, the controller will energize the solenoid, which will rotate the latch <NUM> a small angular distance to disengage the latch catching surface <NUM> from one of the teeth <NUM> of the driver <NUM>. More specifically, this would be the "last" tooth <NUM>.

It should be noted that the rotary motion of the lifter <NUM> will cause a small upward movement of the driver <NUM> so that the latch <NUM> can easily disengage from the "last" tooth <NUM> of the driver <NUM>. Thus, there will not be a binding action that might otherwise cause the mechanism to jam.

Now that all this has occurred, the latch <NUM> is in its disengaged position so that its catching surface <NUM> will not interfere with any of the teeth <NUM> along the right-hand side (as seen in <FIG>) of the driver <NUM>; also the eccentric cam surface <NUM> is now facing the teeth <NUM> along the left-hand side (as seen in <FIG>) of the driver <NUM>, and none of the three "working" pins of the lifter will interfere with those left-hand teeth <NUM>. Once the driver tooth "drops off" the last lifting pin <NUM>, the driver <NUM> is quickly thrust downward in a linear stroke, due to the high gas pressure within the main storage chamber and displacement volume. (This is the "gas spring" effect. ) Along the way, the driver <NUM> will pick up a fastener that is waiting at a feeder carriage (not shown), and drive that fastener to the exit area at the bottom (at the area <NUM> on <FIG>). After this action has occurred, the driver <NUM> will be situated at a lower position in the driver track.

As the driver <NUM> is being moved downward, the piston <NUM>-<NUM> forces air out of the cylinder venting chamber <NUM> that is below the piston-see <FIG>. This volume of air is moved through a vent to atmosphere, and it is desired that this be a low resistance passageway, so as to not further impede the movement of the piston and driver during their downward stroke. The gas above the piston is not vented to atmosphere, but instead remains within the displacement volume <NUM>, which is also in fluidic communication with the main storage chamber <NUM> (through the end cap <NUM>).

Note that some of the embodiments illustrated herein do not have all of their components included on some of the figures herein, for purposes of clarity. To see examples of such outer housings and other components, especially for earlier designs, the reader is directed to other U. patents and applications owned by Senco. Similarly, information about "how" the electronic controller operates to control the functions of the tool is found in other U. patents and applications owned by Senco. Moreover, other aspects of the present tool technology may have been present in earlier fastener driving tools sold by the Assignee, Kyocera Senco Industrial Tools, Inc. , including information disclosed in previous U. patents and published applications. Examples of such publications are patent numbers <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>; also published <CIT> and published <CIT>. These documents are incorporated by reference herein, in their entirety.

It will be further understood that any type of product described herein that has moving parts, or that performs functions (such as computers with processing circuits and memory circuits), should be considered a "machine," and not merely as some inanimate apparatus. Such "machine" devices should automatically include power tools, printers, electronic locks, and the like, as those example devices each have certain moving parts. Moreover, a computerized device that performs useful functions should also be considered a machine, and such terminology is often used to describe many such devices; for example, a solid-state telephone answering machine may have no moving parts, yet it is commonly called a "machine" because it performs well-known useful functions.

As used herein, the term "proximal" can have a meaning of closely positioning one physical object with a second physical object, such that the two objects are perhaps adjacent to one another, although it is not necessarily required that there be no third object positioned therebetween. In the technology disclosed herein, there may be instances in which a "male locating structure" is to be positioned "proximal" to a "female locating structure. " In general, this could mean that the two male and female structures are to be physically abutting one another, or this could mean that they are "mated" to one another by way of a particular size and shape that essentially keeps one structure oriented in a predetermined direction and at an X-Y (e.g., horizontal and vertical) position with respect to one another, regardless as to whether the two male and female structures actually touch one another along a continuous surface. Or, two structures of any size and shape (whether male, female, or otherwise in shape) may be located somewhat near one another, regardless if they physically abut one another or not; such a relationship could still be termed "proximal. " Or, two or more possible locations for a particular point can be specified in relation to a precise attribute of a physical object, such as being "near" or "at" the end of a stick; all of those possible near/at locations could be deemed "proximal" to the end of that stick. Moreover, the term "proximal" can also have a meaning that relates strictly to a single object, in which the single object may have two ends, and the "distal end" is the end that is positioned somewhat farther away from a subject point (or area) of reference, and the "proximal end" is the other end, which would be positioned somewhat closer to that same subject point (or area) of reference.

It will be understood that the various components that are described and/or illustrated herein can be fabricated in various ways, including in multiple parts or as a unitary part for each of these components, without departing from the principles of the technology disclosed herein. For example, a component that is included as a recited element of a claim hereinbelow may be fabricated as a unitary part; or that component may be fabricated as a combined structure of several individual parts that are assembled together. But that "multipart component" will still fall within the scope of the claimed, recited element for infringement purposes of claim interpretation, even if it appears that the claimed, recited element is described and illustrated herein only as a unitary structure.

All documents cited in the Background and in the Detailed Description are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the technology disclosed herein.

Claim 1:
A fastener driving tool (<NUM>), comprising:
a working cylinder (<NUM>, <NUM>) that includes a movable piston (<NUM>, <NUM>), said cylinder including a variable displacement volume (<NUM>) on a first side of said piston, and said cylinder including a variable venting volume (<NUM>) on a second, opposite side of said piston;
a storage chamber (<NUM>) that is operable to be pressurized with gases which are not vented to atmosphere after a drive stroke but re-used for a plurality of operating cycles;
an end cap (<NUM>) that is attached to at least one of said cylinder and said storage chamber near an end portion of said fastener driving tool, said end cap including at least one first gas passageway (<NUM>, <NUM>) that is in fluidic communication with said cylinder and with said storage chamber;
a movable driver (<NUM>) that is in mechanical communication with said piston;
a guide body (<NUM>) that guides movements of said driver; and
a fill valve (<NUM>) that is mounted at a side portion of said end cap, said end cap including a second gas passageway (<NUM>) that travels between an inner end of the fill valve and said at least one first gas passageway (<NUM>, <NUM>) of the end cap, said fill valve being quickly accessible without having to disassemble any portion of a housing of the fastener driving tool;
wherein:
said variable displacement volume (<NUM>) of the cylinder (<NUM>, <NUM>), said storage chamber (<NUM>), and said at least one first gas passageway (<NUM>, <NUM>) of the end cap (<NUM>) all contain the pressurized gases when said fastener driving tool (<NUM>) is in use
wherein-said pressurized gases are not vented to atmosphere after a drive stroke, but instead said pressurized gases are re-used for a plurality of operating cycles.