Elongated-member-driving apparatus – With interlock means
Reexamination Certificate
2001-01-16
2003-08-12
Rada, Rinaldi I. (Department: 3721)
Elongated-member-driving apparatus
With interlock means
C227S130000, C227S120000
Reexamination Certificate
active
06604664
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to pneumatic fastener driving tools, and more particularly to a new and improved pneumatic fastener driving tool wherein the tool has incorporated therein a control system which ensures the safe operation of the tool while effectively permitting the operation of the tool within either one of two rapid fire modes.
BACKGROUND OF THE INVENTION
Pneumatic fastener driving tools are well known in the art and are exemplified by means of U.S. Pat. No. 4,550,643 which issued to Schwartzenberger on Nov. 5, 1985, U.S. Pat. No. 4,405,071 which issued to Austin on Sep. 20, 1983, and U.S. Pat. No. 3,888,404 which issued to Ramspeck et al. on Jun. 10, 1975. Such fastener driving tools conventionally incorporate therein trigger and workpiece contact mechanisms both of which must be activated in order to achieve the discharge or firing of a fastener from the tool. More particularly, a mechanical linkage is operatively connected to a pilot valve such that activation of the pilot valve by means of the mechanical linkage causes the fastener driving tool to cycle and thereby discharge or fire a fastener. The linkage is constructed in such a manner that the movement required to activate the pilot valve is derived from the combined movements of the trigger and workpiece contact mechanisms, although the trigger and workpiece contact mechanisms do not have to be depressed or actuated in any particular manner or order.
Accordingly, if, for example, an operator manipulates or holds the tool in such a manner that the workpiece contact element or mechanism of the tool is constantly maintained in contact with the workpiece or structure, then the tool can discharge or fire a fastener whenever the trigger element or mechanism is also depressed. This mode of operation of the tool is commonly known or referred to as “trigger firing” and obviously provides the operator with a first mode of operation or means for achieving a high level of productivity. This mode of operation is also appreciated to be inherently safe because the workpiece contact element or mechanism is always disposed in contact with a workpiece prior to depression or actuation of the trigger element or mechanism. Alternatively, if, for example, the operator grasps the fastener driving tool by means of its handle in such a manner that the trigger element is constantly depressed, then the tool can discharge or fire a fastener whenever the workpiece contact element is also depressed. This mode of operation of the tool is commonly known or referred to as “bump-firing” and provides the operator with a second mode of operation or means for achieving a high level of productivity. The obvious disadvantage of this mode of operation of the tool is that the tool can be accidentally, inadvertently, or unintentionally discharged or fired if, for example, while the operator is carrying or transporting the tool between different worksites, and while the trigger element is depressed, the workpiece contact element of the tool is inadvertently, accidentally, or unintentionally depressed such as, for example, when the workpiece contact element is accidentally, inadvertently, or unintentionally engaged or moved into contact against some relatively solid object, including the operator, another person, or onsite worker, other than an intended workpiece.
Accordingly, safer versions of pneumatic fastener driving tools require that the trigger and workpiece contact elements of the tool be depressed in a particular order in order to discharge or fire the tool, that is, the workpiece contact element must first be depressed against an intended workpiece, and subsequently, the trigger element must then be actuated. This mode of operation of the fastener driving tool is commonly known or referred to as “sequential firing”. Mechanical linkages incorporated within such tools therefore require that the trigger mechanism must be released and subsequently again depressed or actuated each time a fastener is to be discharged or fired. While the operation of this type of fastener driving tool is thus rendered safer than the previously noted “bump-fire” type of fastener driving tool, it can be readily appreciated that this type of fastener driving tool does not permit the tool operator to achieve a level of productivity which is comparable to that achieved by means of the aforenoted type of fastener driving tool which is being operated in the “bump-firing” mode.
Accordingly, a need exists in the art for a new and improved pneumatic fastener driving tool wherein the trigger and workpiece contact elements are not required to be depressed or actuated in a particular manner or order whereby the tool is able to be operated in both high-speed bump-fire and trigger-fire modes of operation, and yet, the tool is also able to be operated in a safe manner so as to prevent the inadvertent, accidental, or unintentional discharge or firing of the tool despite the fact that an operator may carry or transport the tool between different worksites with the trigger element constantly depressed.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a new and improved pneumatic fastener driving tool.
Another object of the present invention is to provide a new and improved pneumatic fastener driving tool which effectively overcomes the various disadvantages and operational drawbacks characteristic of PRIOR ART pneumatic fastener driving tools.
An additional object of the present invention is to provide a new and improved pneumatic fastener driving tool which is able to be operated in either one of two high-speed bump-fire and trigger-fire operational modes.
A further object of the present invention is to provide a new and improved pneumatic fastener driving tool which is in effect a hybrid type pneumatic fastener driving tool in that the tool is able to be operated in either one of two high-speed bump-fire and trigger-fire operational modes and yet, under certain circumstances, in order to render the tool safe during periods in which fasteners are not to be discharged or fired, the tool cannot be recycled or again discharged or fired unless the tool is initially activated in accordance with a sequential firing mode of operation subsequent to which the tool can also again be discharged or fired in either one of the two high-speed bump-fire or trigger-fire operational modes so as to achieve the desirable high level of productivity.
SUMMARY OF THE INVENTION
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of a new and improved pneumatic fastener driving tool which comprises a housing within which a main valve is disposed and which is adapted to be vented through means of a pilot valve assembly. A workpiece contact element linkage mechanism is operatively connected to a fill valve which is movable so as to fluidically connect the interior of the tool handle, into which compressed air is conducted by means of a suitable fitting, to a reservoir tank. The reservoir tank is in turn fluidically connected to an enable valve assembly so as to provide signal air thereto, and a trigger element or mechanism is operatively connected to the pilot valve assembly as well as to a relief valve assembly.
Accordingly, and initially, when the workpiece contacting element is engaged with a workpiece prior to the depression of the tool trigger element or mechanism, the compressed air is permitted to enter the reservoir tank through means of the fill valve so as to provide the reservoir tank with pressurized reservoir air, the pressurized reservoir air maintains the relief valve assembly closed and is also conducted to the enable valve assembly by means of a signal line, and the compressed air also pressurizes the main valve through means of the pilot valve assembly and the enable valve assembly. Upon subsequent depression of the trigger element or mechanism, the pilot valve assembly is opened, the pressurized reservoir air maintains the r
Ho Tara
Illinois Tool Works Inc.
Rada Rinaldi I.
Schwartz & Weinrieb
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