KR20020084700A - Variable volume valve for a combustion powered tool - Google Patents

Abstract

PURPOSE: A variable volume valve for a combustion-powered tool is provided to measure fluids of regular volume, to supply regular driving force. CONSTITUTION: A variable volume metering chamber(24) and valve assembly for a combustion-powered tool includes a housing defining a metering chamber having an internal volume and including an inlet(20) and an outlet(22), and a plunger configured for reciprocal movement relative to the chamber for adjusting the internal volume of the metering chamber. The plunger is preferably adjustable by the user to alter the volume of fuel retained in the metering chamber. In the housing, a first valve controls control fluid flow through the inlet, a second valve(18) controls fluid flow through the outlet, and an actuator assembly(60), connected to the valves, is sequentially operable from a first position, in which the first valve is open and the second valve is closed, to a second position, in which the first and second valves are both closed, and a third position, in which the first valve is closed and the second valve is open.

Description

VARIABLE VOLUME VALVE FOR A COMBUSTION POWERED TOOL

<Related application>

This patent application is part of a continuing application of co-pending US patent application Ser. No. 09 / 849,606, filed May 4, 2001 entitled "Constant Volume Valves for Combustion Power Tools."

The present invention relates to a constant volume valve for a combustion powered tool, such as a power framing tool. More specifically, it relates to a constant volume valve assembly that measures a volume of fluid prior to being allowed to flow into a combustion chamber.

The invention also relates to pneumatically powered, combustion powered, or other rapidly acting fastener clamping tools of the type utilizing a collated fastener. Typically, Nikolich's U.S. Patent Reissue No. 32,452, Nikolich's U.S. Patent No. 4,522,162; US Patent No. 4,483,474 to Nikolich; As illustrated in U.S. Patent No. 4,403,722 to Nikolich and U.S. Patent 4,483,473 to Wagdy, combustion-powered fastener gripping tools are defined by valve sleeves and cylinder bodies arranged to open and close the combustion chamber. And a combustion chamber. In general, similar combustion powered nails and staple tools are commercially available from ITW Paslode (a business of Illinois Tool Works Inc.) in Burnon Hill, Ill., Under the trade name 'IMPULSE'.

In such a tool, it is desirable to apply a constant force to each fastener during a driving stroke when the fastener is embedded in the workpiece. The measurement of the amount of fuel for combustion powered tools or the amount of compressed gas for pneumatic powered tools helps to provide a constant force. A combustion powered fastener gourd tool that measures fuel by opening a valve for a length of time defined by the movement of the cam is described in US Pat. No. 4,721,240 to Cotta. The fuel passes through the fuel valve and into the combustion chamber conduit, the amount of which is equal to the volume passing through the needle valve for the time that the fuel valve is open. The measurement of fluid flow over time allows the amount of fuel supplied to the tool to change as the flow rate of the fluid changes. When the fuel cylinder is emptied, the flow rate of the fluid changes as the pressure of the cylinder drops. Similarly, changes in pressure or flow in conventional pneumatic fluid supply also cause differences in the amount of power supplied to the filling of each cylinder.

Control of the fuel entering the combustion chamber by the valve assembly is shown in US Pat. Nos. 655,996 and 1,293,858. These two references disclose pressurized fluid inlet valves and fluid outlet valves that function as brackets for machine-supply passages. The high pressure fluid is supplied to the machine through an inlet valve to supply power, and then through the outlet valve when the fluid is returned from the machine following the release of power. Neither of these references teach the use of a system that can supply a certain amount of fluid. In addition, after combustion of fuel or expansion of high pressure fluid, the fluid is no longer useful for powering the tool and the measurement at this point is ineffective.

U.S. Patent No. 4,913,331 to Utsumi discloses a device for driving a piston to an internal combustion engine using a measuring chamber to dispense a volume of fuel. The fuel piston comprising the measuring chamber is reciprocating in the fuel cylinder. The fuel inlet channel and fuel outlet channel are positioned such that the measuring chamber is filled and emptied by the movement of the piston between these inlet and outlet channels. Seals are located on both sides of the chamber between the fuel piston and the cylinder to prevent leakage of fuel from pressurized fuel supplied to the combustion chamber. The steady movement of the pistons can cause rapid wear on these seals because these seals are in constant contact with the surface of the cylinder.

One of the operational drawbacks of conventional combustion powered tools is that the pressure of the pressurized fuel drops when operated at relatively low temperatures, such as below 32 ° F. (0 ° C.), resulting in a large pressure difference between the atmosphere and the fuel. At such low pressures, fuel does not quickly dissipate into the combustion chamber through appropriate passages. This condition causes a combustion delay, which adversely affects the operating efficiency of the tool.

Another drawback in the operation of conventional combustion powered tools is the lack of air for combustion when operated at relatively high elevations or altitudes. As a result, when used at such high ground, conventional combustion powered tools with a volumetric fuel metering valve may have an excessively rich fuel / air mixture in the combustion chamber, which may lead to other operating conditions as well as to the fouling of the ignition system. It can cause difficulties. Thus, there is a need for a combustion powered tool with a fuel metering valve that has the function of regulating the amount of fuel in the combustible fuel / air mixture.

Accordingly, it is an object of the present invention to provide an improved constant volumetric fluid to a device such as a combustion powered tool so as to generate a constant driving force.

Another object of the present invention is to provide an improved constant volumetric fluid in a compact space.

It is a further object of the present invention to provide an improved constant volume valve assembly in which the seal in contact with the sealing surface is not continuously worn.

It is another object of the present invention to provide an improved constant volume valve assembly that facilitates the movement of fuel even when the pressure of the fuel drops, such as when the tool is exposed to low temperatures.

It is a further object of the present invention to provide an improved constant volume valve assembly which provides the function of adjusting the fuel mixture, for example when the tool is operated at relatively high altitude.

1 is a rear view of a constant volume valve assembly of the present invention attached to a fuel canister.

2 is a front vertical cross-sectional view of the constant volume valve assembly of the present invention.

3A-3C show a series of partial cross-sectional views of a constant volume valve assembly of the present invention showing three valve positions as the actuator assembly moves along an operational sequence.

4 is a partial cross-sectional view of the constant volume valve of the present invention shown with a disc for facilitating the movement of fuel from the measurement chamber to the combustion chamber.

5 is a partial cross-sectional view of an alternative embodiment of the constant volume valve of the present invention showing a sealed connection between the valve and the internal nozzle of the pressurized fuel cell.

FIG. 6 is a partial cross-sectional view showing an alternative embodiment of the valve assembly of the present invention, taken in the direction indicated by the arrows along lines 6-6 of FIG. 4.

FIG. 7 shows an alternative embodiment of the valve assembly shown in FIG. 6 in which a metering adjustment shaft is replaced with a heating element. FIG.

<Explanation of symbols for the main parts of the drawings>

10: valve assembly 12: housing

16, 18: first and second (spring deflection) valve

20: entrance 22: exit

24: surveying chamber

28: pressurized fluid bottle / fuel bottle, or fluid source

30, 32: seat 34, 36: (first and second) rods

38, 40 (first and second) springs 42, 44: fixed ends

46, 48: movable end 50: filter

51: nipple 52: upper passage

54: upper chamber 56: lower chamber

60: actuator assembly 62: upper arm

64: lower arm 66: control arm

67: notch 68: pivot link arm

69: tongue 70: combustion chamber passage

71, 72: first and second openers

These and other objects are met or met by the device of the present invention for measuring a volume of fluid to provide a constant energy to the tool. Such devices are most useful for portable fastener gourd tools, powered pneumatically or by an internal combustion engine. In a preferred embodiment, the configuration of the valve and the control mechanism also provides a delay between the closing of one valve and the opening of the other valve to ensure that the fluid is metered before moving downstream towards the combustion chamber.

More specifically, the present invention provides a variable volumetric measurement chamber, wherein the valve assembly for combustion-powered tools has an internal volume and is adapted to adjust the internal volume of the housing and the measurement chamber defined by the measurement chamber including an inlet and an outlet. A plunger configured to reciprocate with respect to the chamber. The plunger is preferably adjustable by the user to change the volume of fuel held in the measurement chamber. Within the housing, the first valve controls the flow of fluid through the inlet, the second valve controls the flow of fluid through the outlet, and the actuator assembly connected to these valves has the first valve open and the second valve From the closed first position, it is possible to operate sequentially from the second position in which both the first valve and the second valve are closed, and the third position in which the first valve is closed and the second valve is open.

The survey valve of the present invention also generates a constant driving force by the fastener clamping tool because it supplies a consistent amount and quality of fuel or hydraulic fluid each time the tool is fired. The supply of fluid to the powered tool of the present invention is measured by volume rather than time, thus providing a more accurate and more consistent supply of power to the tool. As the pressure changes, the density of the fluid changes in these systems because the molecules are denser or coarsely dense. However, in flow systems, the flow rate also changes when the pressure drop across the survey valve changes. The change in flow rate has no effect on the constant volume system as long as the constant volume chamber is filled at the time the inlet valve to the measurement chamber is opened.

In addition, in the present invention, the placement of the measurement chamber and the spring deflecting valve results in a compact space use, which is useful in small portable tools. The colinear arrangement of the valves and the inclination angle of the combustion chamber passages are characterized by a shorter distance from the pressurized fluid source to the combustion chamber compared to other designs.

It is also useful to use spring biased valves to control the flow of fluid. The seat of the valve, which forms a seal for the inlet and outlet of the metering chamber, is in contact with the walls of the chamber only for a relatively short time. When the valve opens and closes, no continuous rubbing of the seal and its adjacent wall occurs. This further extends the life of the seal.

Another advantage of the valve assembly of the present invention is that a disc spring facilitates the flow of fuel into the combustion chamber passage even under operating conditions where the flow of fuel deteriorates, such as when the external operating temperature drops below freezing. It is preferably provided on at least one of the deflection valves.

Another feature of the valve assembly of the present invention is the operation of the upper and lower spring deflection valves to ensure that a specified volume of fuel is retained in the measurement chamber before the lower valve releases fuel into the combustion chamber. The actuator assembly is configured to provide an inherent delay to the device. In a preferred embodiment, this delay is achieved in part by intentional loose engagement between the tongue of the actuator's pivotal link arm and the notch in the actuator's control arm. This loose coupling allows the actuator's control arm to not move continuously while the swing link arm is in constant motion due to the engagement of the tool to the workpiece, thus providing a brief "pause" for the action of the spring biased valve. ) "Is guaranteed. In this way, consistency of the volume of fuel temporarily held in the survey chamber is maintained.

Another feature of the valve assembly of the present invention is that the valve has a control for changing the amount of fuel delivered to the combustion chamber during each firing cycle. This is achieved in a preferred embodiment by providing an adjustable shaft that can be threadably advanced by the user into the fuel metering chamber to reduce the volume of the chamber and thus reduce the available space for incoming fuel. Thus, if more fuel or a richer mixture is desired, the shaft is retracted away from the fuel metering chamber to increase the volume of the chamber. A thinner fuel mixture is obtained by advancing the shaft into the fuel metering chamber.

Another feature of the valve assembly of the present invention is that the adjustable shaft described above can be replaced by an electric heating element for use when the tool is used in colder conditions of the type causing low fuel pressure. The heating element heats the fuel metering chamber itself or a peripheral portion of the valve housing.

<Example>

1 and 2, the constant volume valve assembly and measurement chamber are referred to generally by reference numeral 10. In the detailed description below, the terms "upper" and "lower" refer to assemblies in the orientation shown in the figures. However, it is also contemplated that the assembly of the present invention may be used in a variety of positions as is well known in the art. The valve assembly 10 of the present invention is particularly useful for pneumatic or combustion powered tools (not shown) having a valve housing 12 into which the fluid to be metered is injected under pressure. The valve assembly 10 provides a quantity of fuel to a combustion chamber (not shown) of the tool. Alternatively, it is also conceivable that the valve assembly of the present invention may also measure pressurized air (which is pressurized to be powered) supplied to a pneumatic tool. The valve assembly 10 of the present invention can be used in any tool or device that can benefit from a normal, uniform supply of pressurized fluid.

The housing 12 of the valve assembly 10 is at least two spring-biased valves that respectively control the flow of fluid to the inlet 20 and the flow of the fluid from the outlet 22 of the measurement chamber 24. valves, ie a first spring deflected valve 16 and a second spring deflected valve 18. Survey chamber 24 is defined by housing 12 and optionally has one or more ports in addition to inlet 20 and outlet 22 as described below. The shape of the measurement chamber 24 and the position of the inlet 20 or the outlet 22 are not particularly important. However, it is preferable to position the inlet 20 and the outlet 22 at opposite ends of the measurement chamber 24. In this configuration, the spring deflecting valves 16, 18 are preferably coplanar in approximately the axial direction, thus saving space. In this preferred configuration, the flow of fluid through the measurement chamber 24 flows from the inlet 20 to the outlet 22 generally parallel to the axes of the spring biased valves 16, 18.

Survey chamber 24 may be any type of chamber capable of providing a volume of space for measurement of a fluid, where the volume of fluid collected in the survey chamber is equal to the volume of fluid discharged from the survey chamber. Means. While the fluid is sealed in the measurement chamber 24, the pressure remains constant. The measurement chamber 24 may be a separate vessel or merely a cavity 24 in the housing 12. Housing 12 is also generally used to support other components of the propulsion system, such as pressurized fluid canister 28 (shown in FIG. 1) and spring deflected valves 16, 18. Also used for. Preferably, the measurement chamber 24 is fixed relative to the housing 12.

The volume of the measurement chamber 24 is preferably constant, but is selectively adjustable, for example, by placement of the movable wall or opening of the valve to an additional chamber (not shown). However, utility as a survey application depends on the ability of the chamber 24 to remain constant until some setting, valve or adjustment is intentionally changed.

Each of the spring biased valves 16, 18 preferably comprises conical seats 30, 32, rods 34, 36, and springs 38, 40, respectively. Although discussed in terms of first spring deflecting valve 16, it should be understood that the following description may also apply to corresponding portions of second spring deflecting valve 18. The seat 30 is configured and sized to engage tightly with the inlet 20 of the measurement chamber 24 when the spring biased valve 16 is in the closed position. The movement of the seat 30 between the open position and the closed position is controlled by the rod 34. Although spring 38 is an economical way of deflecting the valve, the use of other deflecting devices is also contemplated. The spring 38 is used to bias the valve 16 to the closed position. Each spring 38, 40 has an anchored end 42, 44 and a movable end 46, 48, respectively. The movable end 46 exerts a force on the seat 30 and moves the seat in the direction of the measurement chamber 24 by the force of the spring 40 which pushes the fixed end 42. The fixed end 42 can be fixed directly to the housing 12, but preferably the fixed end is seated in a compartment described in greater detail below.

The fluid is supplied to the housing 12 under pressure. In general, the tool is preferably portable, in which case the fluid is delivered from a pressurized fluid container 28 that is fitted or attached to the tool. If the tool is used at the factory or elsewhere where a large supply of pressurized fluid is available, the fluid is preferably available to the tool via a hose or similar device (not shown). The valve assembly 10 of the present invention is useful in any of these situations and may be considered for use in any environment. Since temperature and pressure affect the density of any fluid, these factors should be kept as constant as possible to minimize the change in the amount of fluid supplied.

Before entering the valve assembly 10, the fluid preferably passes through a filter 50 (see FIG. 2) to minimize unwanted contaminants. The filter 50 is preferably disposed at one end of the nipple 51, which nipple 51 is engaged in hermetically sealing engagement with the fluid cylinder 28. After passing through the filter 50, the fuel moves to an upper passageway 52. The upper passage 52 leads from the pressurized fluid source, such as the pressurized fluid container 28, to the inlet 20 of the measurement chamber 24. In order to obtain the most consistent amount of fluid, the upper passage 52 is preferably wide enough to achieve a consistent supply pressure prior to closing of the first spring biased valve 16. In some cases, it is desirable to provide the upper chamber 54 for the accumulation of pressurized fluid. Here, for example, the flow rate of the fluid is low, and the fluid accumulates in the upper chamber 54 and provides a predetermined amount of fluid to enter the measurement chamber 24 when the inlet 20 is open. Fluid discharged from the measurement chamber 24 flows into the lower chamber 56. Surveying is accomplished through opening and closing of the first and second spring biased valves 16, 18 by the actuator assembly 60. The actuator assembly 60 may be any mechanism capable of opening and closing the first and second spring biased valves 16, 18 in a particular sequence to allow measurement of the fluid in the measurement chamber 24. Although mechanical linkage is a preferred form of actuator assembly 60, one or more cams of computer control are also examples of possible alternative configurations.

In a preferred embodiment, the actuator assembly 60 is a rod 36 of an upper arm 62 and a second spring biased valve 18 connected to a rod 34 of the first spring biased valve 16. And an C-shaped actuator arm having a lower arm 64 connected thereto. The upper arm 62 and the lower arm 64 are connected to each other by a control arm 66 (see FIG. 1). Notches 67 in control arm 66 are engaged by pivoting link arms 68 which pivotally engage housing 12 at point '68a'. The specific engagement between the link arm 68 and the notch 67 is through the tongue 69. Swivel link arm 68 is actuated through the movement of a nosepiece valve linkage (not shown), the structure and operation of the nosepiece valve linkage being described in the Nikolich patent incorporated herein by reference. It is described.

An important feature of the actuator assembly 60 of the present invention is the movement of the arms 62, 64, 66 and deflection of the upper and lower springs by these arms so that a volume of pressurized fluid can be temporarily maintained in the measurement chamber 24. There is a delay in the operation of the valves 16 and 18. This delay is caused in part by loose interlocking engagement between tongue 69 and notch 67. In a preferred embodiment, the tongue 69 is provided with a reduced area compared to the notch 67, so that the pivot link arm 68 does not cause the movement of the arms 62, 64, 66 of its arcuate travel path. You can move a little along the way. The looseness or “sloppiness” of the coupling between tongue 69 and notch 67 may vary depending on the application, including notches in the link arm and tongues in the control arm 66. The specific configuration of the engagement coupling may also be changed.

The actuator assembly 60 moves the first and second spring biased valves 16, 18 in either the first valve sequence or the second valve sequence depending on which valve is open and which valve is closed. The valve sequence is determined in accordance with the combustion cycle in the case of combustion tools or in the impact cycle in the case of pneumatic tools.

Turning now to FIGS. 3A-3C, a sequence of valves is described. The start of the first valve sequence is defined when the tool is in use. In this position, the tool is in the ON state and ready for use, but not yet in contact with the workpiece to which the fastener is lodged. At this time, the actuator assembly 60 is in the first position, as shown in FIG. 3A, and the arm 62 is spaced at a maximum distance from the opposing wall of the housing 12. The first spring biased valve 16 is in the open position and the second spring biased valve 18 is closed. The measurement chamber 24 is thus filled with fuel or fluid as it is in circulation with the fuel cell / fluid cylinder 28 through the passage 52.

During the first valve sequence, the first spring deflected valve 16 moves from the open position to the closed position and the second spring deflected valve 18 opens, but the second valve remains until the first valve is fully closed. Do not start opening. This first valve sequence is generally triggered by some triggering action in preparation for the launch of the tool. To drive the fasteners with power, the measured fluid is moved to a location capable of generating such power, ie fuel is moved to the combustion chamber or air is moved to the expansion cylinder. The sequence is preferably initiated by any preparatory mechanism, such as contact of the tool to the workpiece, initiation of the pressing of the trigger mechanism, and the like. If a combustion powered work tool is used, the priming of the combustion chamber is preferably generated when the workpiece contact element is in contact with the workpiece, so that fuel flows out of the measurement chamber 24 and passes through the lower chamber 56. It enters the combustion chamber passage 70 and ultimately into the combustion chamber (not shown). In the preferred embodiment illustrated, the sequence is initiated by contacting the tool to the workpiece, which causes the pivot link arm 68 to begin its arcuate travel path indicated by arrow A (see FIG. 1).

It is important to note that the measurement chamber 24 is used only for the measurement of the fluid and there is no physical or chemical change in the fluid while it is sealed in the chamber. To provide a constant power, the fluid is preferably delivered at the same volume, temperature and pressure for each cycle. Since the fluid cannot be measured accurately during a chemical or physical reaction, the fluid preferably has the same chemical composition as it enters the measurement chamber when it is discharged from the measurement chamber 24.

Referring now to FIG. 3A, which corresponds to the first position in the preferred embodiment shown, in this position, fluid freely enters the measurement chamber 24. As the pivoting link arm 68 moves in an arc indicated by arrow A, the tongue 67 moves in the opposite arcuate direction. Thus, the upper upward pressure exerted on the first rod 34 by the upper arm 62 is released, so that the spring 38 deflects the first seat 30 of the first valve 16 so that the measurement chamber ( 24 is in engagement with the inlet 20.

At this point, the two spring deflecting valves 16, 18 are closed to prevent the flow of fluid from the fluid reservoir 28 to the measurement chamber 24 and the flow of fluid from the measurement chamber 24. This position is illustrated in FIG. 3B, which corresponds to the second position of the actuator assembly 60. The metering chamber 24 is closed at both the inlet 20 and the outlet 22 to seal off the fluid therein and provide a volume of fluid measured within the chamber.

The loose interlocking engagement between the tongue 69 and the notch 67 described above allows the second valve 18 to continue while the pivot link arm 68 continues its arcuate path, indicated by arrow A (see FIG. 1). Causes a momentary delay in opening. Due to the loose coupling, when the swing link arm 68 is moved, there is a delay while the upward deflection force that opens the first valve 16 is released, and the control arm 66 is still in the second valve 18. It did not move enough to open. This delay ensures that the volume of fuel in the measurement chamber 24 remains constant and prevents unwanted additional amounts from entering the chamber or premature leakage of fuel from the outlet 22 into the lower chamber 56. do.

The third position of the actuator assembly 60 is shown in FIG. 3C, which is achieved after the first valve 16 is completely closed and the second spring biased valve 18 is opened. In this position, fluid is discharged from the measurement chamber 24. In a preferred embodiment, the entirety of the first valve sequence is generated as the actuator assembly 60 moves from the first position through the second position to the third position.

Following the firing of the tool, a second valve sequence is initiated, in which the pivot link arm 68 moves the actuator assembly 60 from the third position to the second position by lifting the tool from the workpiece. Move to position 1. This sequence blocks the outlet 22 of the measurement chamber 24 to prevent flow downstream, and reopens the inlet 20 to allow flow of fluid back into the measurement chamber 24. Any triggering action after the launch of the tool but before the first valve sequence can be used for the initiation of this sequence.

The second valve sequence is the same as the first valve sequence but in the reverse order to move the first and second spring deflected valves. Starting from the third position of the actuator assembly 60 shown in FIG. 3C, the second spring biased valve 18 is separated from the outlet 22, thereby preventing fluid from flowing out of the measurement chamber 24. After the second valve is fully closed, a second position of the actuator assembly 60 as shown in FIG. 3B is obtained. Here both valves 16 and 18 are closed to prevent backflow of the fluid, and the measurement chamber 24 contains only the remaining amount of fluid. Finally, the first spring biased valve 16 is disconnected from the inlet 20 to allow free flow of fluid from the fluid source 28 to the measurement chamber 24, but the fluid is from the pressurized fluid source 28. Free flow to the combustion chamber passage 70 through the inlet 20 and the outlet 22 of the measurement chamber 24 is prevented.

In a preferred embodiment, this operation or valve sequence causes the actuator assembly 60 to be moved from the position where the upper arm 62 has the greatest distance from the housing 12 (FIG. 3A) from the housing 12 to the lower arm 64. It is controlled by the turning operation of the link arm 68 which moves to the position with the largest space | interval (FIG. 3C). In a preferred embodiment, in addition to the loose interlocking engagement between the notch 67 and the tongue 69, the actuator assembly 60 also has the closure of one of the valves 16, 18 and the other valve 18, 16. Also included is a delay mechanism that operates between closures. Any type of delay mechanism is suitable, such as electronic means of an electrical retarder or a mechanically delayed mechanism. In the most preferred mechanical delay mechanism, the actuator assembly 60 is slidably connected to each of the rods 34 and 36. The first rod 34 has a first opener 71, such as a C-clip secured to the rod 34, and the second rod 36 has a second opener 72. The spacing of the openers 71, 72 on the rods 34, 36 is preferably used to cause a delay in the closing of one valve 16, 18 before the other valve 18, 16 opens.

In the preferred delay mechanism, the control arm 66 of the actuator assembly 60 is longer than the housing 12 in which the valve assembly resides. This excess length allows the upper arm 62 and the lower arm 64 to have the housing 12 interposed between these arms with an excess space between the housing and the arms 62 and 64 of the actuator. Enough to do it. In response to the triggering action to trigger the valve sequence, the control arm 66 moves up and down (relative to the tool in the orientation of FIG. 3).

Referring now to FIG. 3A, as actuator assembly 60 moves through the first valve sequence. The upper arm 62 begins to contact the first opener 71. As the control arm 66 moves downwards. The release or expansion of the first spring 38 causes the first opener to be opened against the upper arm 62 until the first seat 30 contacts the inlet 20 of the surveying chamber to close the first spring biased valve. 71). After the control arm 66 has sufficiently moved so that the upper arm 62 is separated from the first opener 71 (as shown in FIG. 3B), the first spring 38 moves the valve 16 to the closed position. Deflect. During this movement of the control arm 66 from the first position (FIG. 3A) to the second position (FIG. 3B), the lower arm 64 moves along the second rod 36 and partially but not entirely. Decompress the spring 40. Next, upon movement of the control arm 66 from the second position (FIG. 3B) to the third position (FIG. 3C), the lower arm 64 slides along the second rod 36 and finally the second arm. In contact with the opener 72, the second spring 40 is compressed to open the second spring biased valve 18. The second valve sequence reverses the above steps in a similar manner, imparting a delay between the closing of the second spring biased valve 18 and the opening of the first spring biased valve 16.

Seals are used where appropriate to prevent flow of fluid into the valve assembly 10, the survey chamber 24, and the areas outside the housing 12. The exact number, shape and arrangement of these seals depends on the exact configuration of the valve assembly 10 for the particular application. In the preferred embodiment shown, a removable insert 74 has a rod 34 for each of the spring biased valves 16, 18 when the rod passes through the housing 12 and contacts the actuator assembly 60. And 36). O-rings 76, gaskets or similar devices are preferably used to prevent leakage between the removable insert 74 and the housing 12 or rods 34, 36. In some applications, it is desirable for the length of the springs 38, 40 to be larger than the dimensions of the upper chamber 54 or the lower chamber 56. When this is desirable, the removable insert 74 is configured to receive a portion of the length of the springs 38, 40 and to accommodate the fixed end 42 and is sized in a hollow compartment 78. It includes. The removable insert 74 also provides easy access to the spring biased valves 16, 18 and other components when a replacement part is installed.

Referring now to FIG. 4, the valve assembly 10 of the present invention includes a method for facilitating the movement or discharge of fuel from the measurement chamber 24, through the outlet 22 and finally to the passage 70 leading to the combustion chamber. It is preferred that a mechanism be provided. As mentioned above, it has been found that when this type of combustion powered tool is operated at low temperatures, such as below 32 ° F. (0 ° C.), the pressure of the fuel drops and it becomes more difficult to move the fuel into the combustion chamber. In order to solve this problem, the valve assembly 10 of the present invention preferably has a disk 80 fixed to the valve 18, in particular at the end of the rod 36 arranged in the survey chamber 24. Is provided. The disk 80 is preferably located closer to the inlet 20 when the valve 18 is closed. To this end, the disk 80 is fixed to a pedestal 82, which in turn is secured to a conical sheet 32. In a preferred embodiment, the disk 80 is made of brass or a material having equivalent stiffness and heat resistance, and the pedestal 82 is made of rubber or similar elastomeric or plastic material. However, other materials can also be considered. Preferably, the disk 80 is frictionally fitted to the pedestal 82 via a frictional engagement between lugs 84 on the pedestal and the axial bore 86 of the disk. . However, other methods of securing the disk 80 to the pedestal 82 may be contemplated, including but not limited to ultrasonic welding, insert molding, adhesives or other mechanical fasteners. The disk 80 is dimensioned to have a diameter closer to, but smaller than, the diameter of the measurement chamber 24.

In operation, when the valve 18 is opened, as described above in connection with FIG. 3C, the disk 80 is at its rest near the inlet 20 of the survey chamber 24 (best seen in FIG. 4). It moves with the seat 32 from a position to a position closer to the outlet 22. This movement pushes the remaining fuel from the measurement chamber 24 via the outlet 22 into the passage 70 which ultimately leads to the combustion chamber. In this way, fuel is mechanically moved out of the measurement chamber 24. However, since the problem of low fuel pressure is temperature-related, an alternative complementary exhaust passage 88 is provided, through which the hot exhaust gas from the combustion chamber heats up the measurement chamber during operation of the tool. . As an equivalent device, another known device is provided which maintains a satisfactory temperature in the measurement chamber 24 so as to maintain the pressure of the fuel or electrical heating element powered by a resistor.

Referring now to FIG. 5, the connection between the valve assembly 10 and the fuel container 28 is shown in great detail. It is important to establish a sealing relationship between the valve assembly 10 and the fuel container 28 not only to prevent fuel loss but also to prevent unwanted combustion. Fuel cell 28 is provided with an internal stem 90 that defines an outlet for fuel contained within the fuel cell under pressure, as is known in the art. As illustrated in US Pat. No. 5,115,944, which is well known in the art and incorporated herein by reference, the stem 90 surrounds an end of the fuel container 28 and has a rolled seam 94 thereon. It is secured to the end cap 92, which is formed and surrounded by the end cap.

Adapter 96 frictionally engages end cap 92 and surrounds protruding stem 90 to protect it. The axial passageway 98 is defined by the adapter 96 and receives the stem 90. In a preferred embodiment, the adapter 96 also includes a frangible end membrane 100 that blocks the passage 98 and provides a visual indication of whether the fuel container 28 has been used. . The thin film 100 is configured to be penetrated upon engagement with the nipple 51. Thus, the passage 98 is dimensioned to accommodate the nipple 51.

In addition, the nipple 51 is preferably generally cylindrical in shape such that a fluid flow relationship is established between the fuel container 28 and the valve assembly 10 and is dimensioned to be able to slide and engage with the passage 98. Has a defined diameter or cross-sectional parameter and a length of dimension that can be engaged with the end 102 of the stem 90. In a preferred embodiment, the nipple 51 is cylindrical, but other cross-sectional shapes other than circular may be contemplated, depending on the application, and include elliptical, square, rectangular and polygonal shapes.

In a preferred embodiment, the nipple 51 and the stem 90 are configured such that when in engagement coupling as illustrated in FIG. 5, a sealing relationship is achieved. This relationship to prevent unwanted loss of fuel can be achieved through frictional contact between the end 102 of the stem 90 and the end 104 of the nipple 51. However, it is preferable that some kind of sealing formation is provided on at least one of the nipple 51 and the stem 90. In a preferred embodiment, the seal formation is an elastic O-ring provided in the nipple 51. However, other known types of hermetic formations can be envisioned, including but not limited to ring seals, molded seals and flat washers.

In addition, the nipple end 104 of the present invention defines a chamber 108 for receiving or holding an elastic sealing member, such as an O-ring 106. More specifically, the end 104 is tapered or chamfered to retain the O-ring 106 and to facilitate insertion of the nipple 51 into the adapter passage 98. The tapered end 104 penetrates the membrane 100 more easily, especially when the nipple 51 is made of a metal such as brass, and the nipple 51 is preferably made of a metal such as brass, although other suitable Consider materials with stiffness and durability.

In order to further enhance the sealing relationship of the coupled nipple 51 and the stem 90, the end of the stem 102 is configured to engage or receive the O-ring 106 in engagement. As such, the end 102 is preferably provided with an annular groove 110. Naturally, the o-ring 106 or other resilient sealing member is alternatively mounted to the stem 90, or the nipple end 104 by an adhesive in a groove (not shown) or by another known type of O-ring attachment technique. It is also conceivable that it can be attached.

In addition, depending on the application, if fluid flow with the fuel container 28 is desired for any reason, the nipple 51 is in fluid flow with the fluid container or reservoir at the opposite end of the end 104, if desired. A connector may be provided.

In use, the fuel container 28 is inserted into the combustion tool such that the nipple 51 is engaged with the adapter 96. The fuel cell 28 is pressed against the nipple 51 so that the membrane 100 penetrates and enters the passage 98 until the nipple end 104 makes contact with the stem end 102. As mentioned above, it is also contemplated that other locking apparatus may be used to secure the fuel cell 28 in this position, as the sealing relationship is preferably obtained.

Thus, it will be appreciated by those skilled in the art that the valve assembly and measurement chamber of the present invention provide a simple method of supplying a volume of fluid to a powered fastener drive tool. Two spring-biased valves 16, 18 control a volume of inlet and outlet to the measurement chamber 24 to measure a certain amount of fluid regardless of fluctuations in the flow rate of the fluid. The actuator assembly 60 manipulates the opening and closing of the valves 16 and 18 to take the fluid from the pressurized fluid source 28 and survey it before flowing downstream to the combustion chamber or expansion chamber. This arrangement of valves 16, 18 minimizes wear on the seal and reduces maintenance.

Referring now to FIG. 6, another embodiment of a valve assembly of the present invention is generally referred to as reference numeral 120. Common components of the valve assemblies 10, 120 are identified by the same reference numerals. The main difference between the two valve assemblies 10, 120 includes a mechanism by which the valve assembly 120 changes the volume of the fuel measuring chamber 24, so that the volume of fuel sent by the valve assembly to the combustion chamber of the tool is determined. The user can selectively adjust. This adjustability is especially useful when used in high altitudes or elevations where air is scarce and less fuel is required for efficient combustion.

In a preferred embodiment, the mechanism for changing the volume of the fuel measuring chamber 24 is a dosage plunger 122, referred to in this embodiment as a plunger, which is oriented to reciprocate in a straight line with respect to the measurement chamber 24. Long absence. The plunger is preferably reciprocated along a longitudinal axis generally perpendicular to the operating axis defined by the valves 16, 18.

The plunger 122 is assumed to have any shape that can withstand the operating environment of the combustion tool and occupy the space of the measurement chamber 24, which is occupied by fuel if the plunger is not occupied. can see. In a preferred embodiment, the plunger 122 is an elongated metal shaft or rod having a valve end 124 and an adjusting end 126. As mentioned above, the valve end 124 is configured to reduce the volume of the measurement chamber 24 by occupying a certain space, which is occupied by fuel if the plunger is not occupied, prior to every firing cycle of the tool. It is composed. As illustrated herein, the valve end 124 is generally cylindrical with a truncated end, although the end may alternatively be considered to have a shape complementary to the wall 128 of the survey chamber 24. .

On the opposite side of the valve end 124, the adjusting end 126 is configured to allow for selective manipulation, here axial rotation, which is achieved by the screwdriver slot 130 in a preferred embodiment. do. Driver slots of any conventional shape are also considered suitable and include, but are not limited to, slotted Phillips Tor-x, etc., as well as hexagon wrenches for Allen wrenches or conventional sockets. On-demand adjustment schemes are also conceivable for use where the adjustment of the tool is permitted only to certain qualified service personnel.

Between the valve end 124 and the adjusting end 126, the plunger is preferably controlled so that the axial reciprocating motion of the valve end 124 can be reliably controlled into and out of the measurement chamber 24. Threaded portion 122 is provided. Any equivalent structure for achieving this purpose is also contemplated. In addition, the plunger 122 has a length sufficient to allow adjustment outside the valve housing 12.

The sleeve 132 is mounted to the valve housing 12 in an operative relationship and is configured to reciprocally receive the plunger 122. More specifically, the sleeve 132 surrounds and supports the plunger 122 and is preferably secured to the housing 12 by press fit to the bore 134. Bore 134 is in flow relationship with survey chamber 24. Other methods of securing the sleeve 132 to the housing 12 are also contemplated, including welding, chemical adhesives, and the like. Sleeve 132 is provided with a central, axial through bore 136 that is in flow communication with measurement chamber 24 and dimensioned to receive plunger 122. In order to properly support the plunger 122, the sleeve 132 has a sufficient length extending generally perpendicular to the valve housing 12. However, the plunger 122 is preferably longer than the sleeve 132. The outer end 138 of the sleeve 132 is preferably threaded to allow engagement with the threaded portion of the plunger 122. Corresponding threaded portions of the plunger 122 and sleeve 132 may be modified to suit the application.

Since not only the bores 134 but also the through bores 136 are in fluid communication with the measurement chamber 24, it is important that these bores are sealed to prevent unwanted fuel leakage. Thus, the sleeve 132 is preferably provided with an o-ring shaped seal 142 located in an o-ring groove 144 having appropriate dimensions. Depending on the application, groove 144 may be located on sleeve 132 or in bore 134. Plunger seal 146, which is also preferably an O-ring, also seals through bore 136 and is disposed in groove 148 in through bore 136 or plunger 122.

In order not to deteriorate the operation of the valves 16, 18, the plunger 122 is preferably arranged in the survey chamber at an offset position. In other words, the longitudinal axis of the plunger 122 is offset from the vertical plane which bisects the measurement chamber 24 in the reciprocating direction of the plunger. Indeed, and now referring to FIG. 6, the plunger 122 is located behind the axis of movement of the valves 16, 18.

Referring now to FIG. 7, another feature of the system 120 of the present invention is that the plunger 122 can be used even at relatively low temperatures (below 32 ° F = 0 ° C) when the fuel pressure drops as described above. Or sleeve 132 is heated. Heat is supplied electrically by connecting a live lead 150 which is powered by a battery (not shown) of the tool.

Alternatively, heat may be provided by replacing the plunger 122 with the fixed heating element 152. The heating element 152 may reciprocate in the sleeve 132 through frictional engagement, and it is also contemplated to be connected to the battery as is well known in the art. Additional heat may be provided from the combustion chamber, as described above in connection with the complementary exhaust passage 88 (see FIG. 4).

While particular embodiments of constant volume valve assemblies and measurement chambers have been shown and described, it will be understood by those skilled in the art that changes and modifications may be made to these embodiments without departing from the various aspects of the invention and the disclosure in the appended claims. .

As described above, the present invention is capable of supplying an improved constant volume of fuel even in dense spaces, reducing the wear of the seal against the sealing surface, and reducing the fuel pressure even when the tool is exposed to low temperatures and the pressure of the fuel drops. Easier transfer, smoother combustion improves operating efficiency, and also allows the proper fuel / air mixture to be supplied to the combustion chamber by controlling the amount of fuel even when the tool is operated at high altitude and the air for combustion is scarce. Has an effect.

Claims (11)

A volumetric metering chamber and valve assembly for use in a pressurized fluid supply comprising fluid in a combustion powered tool, the assembly comprising: A housing defining a survey chamber having a plurality of ports, including an inlet and an outlet; A first spring-biased valve disposed in the housing for controlling the flow of fluid through the inlet, A second spring biased valve disposed in the housing for controlling the flow of fluid through the outlet; The first and second spring deflected valves from a first position connected to the first and second spring deflected valves, the first spring deflected valve being open and the second spring deflected valve being closed; An actuator assembly that is sequentially operable to a second position where both are closed and to a third position where the first spring biased valve is closed and the second spring biased valve is open; A volume of fluid entering the chamber from the inlet at the first position to provide a volume of fluid for each sequential movement of the actuator from the first position to the third position The valve assembly collected within and confined within the measurement chamber at the second position and configured and arranged to be discharged from the measurement chamber at the third position. And a volumetric volumetric chamber and valve assembly. 2. The actuator assembly of claim 1 wherein the actuator assembly includes both the first and second spring biased valves from the third position where the first spring biased valve is closed and the second spring biased valve is open. The second position being closed and the first spring deflecting valve are open and operable to the first position being closed and the second spring biasing valve is closed, so that the first position from the third position of the actuator is For each sequential movement to one position, after the volume of fluid is discharged from the survey chamber at the third position to provide a volume of fluid, the survey chamber is opened at the second position. Hermetically sealed to prevent backflow of the fluid, wherein the survey chamber is refilled with a volume of fluid at the first location Ever measurement chamber and the valve assembly. The volumetric measurement chamber and valve assembly of claim 1, wherein the measurement chamber is configured and arranged such that the volume of fluid collected is equal to the volume of fluid discharged from the measurement chamber. The volumetric volumetric chamber and valve assembly of claim 1, wherein the survey chamber is provided with an apparatus for facilitating the discharge of fuel from the chamber. Further comprising a delay mechanism configured to cause a delay between the closing of one of the first and second spring biased valves and the opening of the other of the first and second spring biased valves. And a volumetric volumetric chamber and valve assembly. 6. The valve of claim 5, wherein each of the first and second spring biased valves comprises a biased rod, and the actuator assembly is slidably connected to each of the rods between the housing and the opener. And the opener is placed on the rod such that a delay is caused by a sliding motion of the actuator assembly between the opener of one of the spring biased valves and the opener of the other of the spring biased valves. A volumetric metering chamber and valve assembly positioned. 7. The actuator assembly of claim 6, wherein the actuator assembly is configured to engage the control arm to cause the actuation with a control arm configured to actuate the first and second spring biased valves. A pivoting link arm, wherein the control arm and the pivoting link arm are configured to have a loose interlocking engagement to cause the delay. The volumetric volumetric chamber and valve assembly of claim 1, further comprising means for adjusting the internal volume of the surveying chamber. 9. The volumetric volumetric chamber and valve assembly of claim 8, wherein the adjustment means comprises a plunger configured to make adjustable reciprocating motion relative to the measurement chamber. The volumetric volumetric chamber and valve assembly of claim 1, further comprising a heater provided in an operational relationship to the housing for heating the survey chamber. A housing having an internal volume and defining a survey chamber comprising an inlet and an outlet; Means for adjusting the internal volume of the survey chamber; And a variable volumetric measurement chamber and valve assembly for use in a combustion powered tool.