Referring now to
As described in U.S. Pat. No. 5,263,439, incorporated by reference, inserted into the fuel cell chamber 14 is a fuel cell, generally designated 20, the general construction of which is well known in the art pertaining to combustion tools. The particular construction of the present fuel cell 20, having an internal fuel metering valve 22 (
Other major components of the fuel cell 20 include an outer shell 30, a closure 32 crimped over an upper end of the shell, and a snap fit stem protector 34. Frictionally engaged in the closure, the stem protector 34 includes a generally cylindrical sleeve 36 surrounding and extending vertically beyond an upper end of the stem 24. The sleeve 36 protects the stem 24 from damage or unwanted actuation to avoid inadvertent dispensing of fuel.
Also included on the nailer 10 is a fuel cell actuator assembly generally designated 38 which is in operational relationship with the fuel cell chamber 16 and is constructed and arranged for exerting an axial force on the fuel cell stem 24. This axial force causes the stem 24 to dispense a measured dose of fuel to the combustion chamber 14 prior to each combustion event to initiate combustion. A main component of the actuator 38 is at least one generally elongate actuator element 40 configured for exerting an axial force on the stem 24, releasing the dose of fuel. In the preferred embodiment, the element 40 is in actual contact with the stem 24.
In a generally inverted “U”-shaped channel 42 defined by the actuator element 40 is disposed a fuel delivery apparatus including a stem receiver block 44. The stem receiver block 44 is held within the channel 42 by at least one pin (not shown) passing through a corresponding bore on both the actuator element 40 and the stem receiver block. However, other types of fastening arrangements, such as threaded fasteners, chemical adhesives or the like are also contemplated. While the stem receiver block 44 is located at an end of the actuator element 40, other locations on the element are contemplated. A depending nozzle 48 on the stem receiver block 44 matingly engages the sleeve 36 and defines a socket 50 dimensioned for positively and sealingly engaging the valve stem 24. Note that in this embodiment, the nozzle 48 passes within the sleeve 36 for direct engagement with the valve stem 24.
Also included in the fuel delivery apparatus is an internal passageway 52 (shown hidden) in the stem receiver block 44 that places the fuel cell valve stem 24 in fluid communication with a fuel conduit 54 associated with the actuator element 40, in this case by being located in the channel 42. It will be understood that the passageway 52 generally defines a right angle, so that fuel dispensed by the generally vertically oriented fuel cell 20 and the stem 24 is diverted to a generally horizontal direction. However, the configuration of the passageway 52 may vary to suit the application. The fuel conduit 54 places the fuel cell valve stem 24 in fluid communication with the stem receiver block 44 and also with a cylinder head 56 of the tool 10. As is known in the art, the cylinder head 56 is one of the components defining the combustion chamber 14. Also, the fuel conduit 54 is preferably a segment of flexible tubing and is joined both to the cylinder head 56 and to the stem receiver block 44 by corresponding barbed fittings 45 (
The actuator element 40 pivotally engages the cylinder head 56 through a pinned connection of at least one and preferably two tabs 58 at an opposite end of the element from the location of the stem receiver block 44. The tabs 58 engage ears 60 extending in a spaced, generally parallel orientation from the cylinder head 56. This pivoting connection allows the actuator 38 to be pivoted out of the way to permit a fuel cell exchange (
Also included on the actuator 38 is a pivot member 62 provided for transmitting the axial force to the actuator which dispenses the measured dose of fuel from the fuel cell 20. This force originates through the retraction of a workpiece contact element (not shown), depending from a lower end of the tool. As is well known in the art of fastener driving tools, as the tool 10 is pressed against the workpiece prior to driving a fastener, the workpiece contact element retracts relative to the rest of the tool. This retraction is used to mechanically trigger other operations of the tool 10, such as the closing of a combustion chamber by a valve sleeve. In the present application, the movement of the workpiece contact element relative to the tool 10 also is used to initiate the axial force on the fuel cell stem 24 to dispense the fuel.
More specifically, the workpiece contact element is mechanically coupled to a valve sleeve 64 having at least one and preferably a plurality of vertically projecting lugs 65, (
A laterally extending lug 70 extends from the pivot member 62 and pivotally engages a corresponding socket or opening formation 72 (
Once the tool 10 is pressed against a workpiece and the workpiece contact element is retracted relative to the tool, the link rods 64 extend upwardly, pivoting the pivot member 62 about the lugs 70, causing the bar 68 to axially depress the actuator element 40, which in turn presses an engagement surface 74 on the stem receiver block 44 downwardly against the stem 24. This downward axial force overcomes the bias of the stem 24 and is stopped by engagement between the stem receiver block 44 against the sleeve 36, however, the vertical travel of the stem receiver block is sufficient to depress the stem 24 to release and dispense the measured dose of fuel. Thus, the actuator 38 is configured for receiving a force in a first axial direction, and associated with the actuator element 40 for generating an opposite axial force on the stem. At the conclusion of the combustion cycle, when the tool 10 is lifted from the workpiece, the link rods 64 retract and the actuator 38 resumes the rest position of
Referring now to
More specifically, the actuator block 82 shares many components with the stem receiver block 44, but also defines a stem cavity 86 dimensioned to envelop the main stem 24 without contacting the stem when the fuel cell 20 is adapter-free. As seen in
Referring now to
An upper portion of the adapter body 92 defines a locator ring 100 with an open upper end 102 for receiving the actuator block 82 (
Also on the first end is an annular foot 114 which acts as a stop against the fuel cell closure 32. This stop is important in restricting the amount of depression of the main stem 24 through operation of the actuator 38 or other vertical force, even that generated by a user. Excessive depression of the main stem 24 may cause more than the predetermined dose of fuel to be dispensed.
A second end 116 of the hub 106 opposite the first end 108 is configured for engaging and being in sealed fluid communication with the actuator block 82. Preferably, the second end 116 of the hub 106 and the stem cavity 86 are complementarily shaped to have a tight friction fit. This tight fit facilitates physical connection between the hub 106 and the block 82 and maintains a sealing relationship to prevent fuel leakage. However, additional fastening and sealing formations, such as lugs and detents, locking clips, annular lip seals or crush ribs or other fastening and sealing formations for releasably and sealingly securing the actuator block 82 upon the hub are contemplated.
A feature of the adapter 84 is that the hub 106 is reciprocally movable relative to the body so that the hub can follow the cyclical movement of the main stem 24. Thus, the hub 106 accommodates the motion induced into the system by the actuator 38, as well as by the spring 26 in the fuel cell 20. In the preferred embodiment, the reciprocal movement is provided by at least one curved flexible member 118 which is secured at a first end to the adapter body 92 and at an opposite end to the hub 106. The flexible members 118 are designed to add only a negligible force to that required to depress the fuel valve stem 24 in the fuel cell 20. In construction, the flexible members 118 are spiral in shape and have a generally circular cross-section to enhance the flexibility while reducing torsional stiffness.
There are preferably three curved flexible members 118, and they basically suspend the hub 106 relative to the body 92. In addition to the suspending function, the flexible members 118 bias the hub to a rest position shown in
Referring now to
Included on the hub 126 is a lower end defining an internal bore 110 dimensioned to slidably receive the valve stem 24, and the fuel bore 112 in communication with the internal passageway 52 in a modified actuator block 134. The block 134 includes a depending sleeve 136 dimensioned to slidably and matingly engage the opening 132 and also to contact an upper surface 138 of the flange 128. As is the case with the adapter 84, in the adapter 120 the hub 126, shown with a truncated conical configuration 140, tightly yet releasably engages a complementarily-shaped recess 142 in the actuator block 134 so that there is tight, leak resistant fluid communication between the fuel cell valve stem 24 and the internal fuel passageway 52.
It will be seen that with the present fuel delivery apparatus, and specifically the actuator block 82, for fuel to ultimately be communicated from the fuel cell 20 to the combustion chamber 14, the adapter 84, 120 must be in place. Otherwise, the hubs 106, 126 will merely engage the fuel cell closure 32 and not the valve stem 24. Absent the adapter 84, 120, the actuator 38 will not actuate the valve stem 24.
While particular embodiments of the present enhanced fuel passageway and adapter for combustion tool fuel cells have been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.
This application claims priority from co-pending U.S. provisional patent application Ser. No. 60/817,864 filed Jun. 30, 2006, which is incorporated herein by reference.
Number | Date | Country | |
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60817864 | Jun 2006 | US |