Elongated-member-driving apparatus – With interlock means
Reexamination Certificate
2000-03-31
2001-04-03
Smith, Scott A. (Department: 3721)
Elongated-member-driving apparatus
With interlock means
C227S142000, C227S120000
Reexamination Certificate
active
06209770
ABSTRACT:
BACKGROUND OF THE INVENTION
Power operated fastener driving devices are in widespread use in the construction and building trades and typically include a power operated driving mechanism mounted within a housing that powers the driving movement of a drive element slidably mounted within a drive track that extends through a nose piece mounted to the housing. Typically when the driving mechanism is actuated, the drive element moves in a fastener driving direction through a drive stroke and then moves in the opposite direction through a return stroke during one cycle of operation. A trigger mechanism that is movable through an actuation stroke is commonly provided on the exterior of the housing to initiate an operating cycle.
A magazine assembly mounted to the housing supplies a series of fasteners to the drive track through a lateral opening in the same and the leading fastener in the drive track is driven outwardly of the drive track into a workpiece by the driving movement of the drive element when the driving mechanism is actuated. Typically a spring biased fastener feeding device advances the fasteners through the magazine toward and into the drive track.
It is not desirable to actuate the driving mechanism when there is no fastener in the drive track or when the drive track is not in contact with a workpiece that will receive the fastener, because it is preferable that the energy transferred to the driving element and related structures during the drive cycle be absorbed by the movement of the fastener into the workpiece. When no fastener is present in the drive track when the driving mechanism is actuated, for example, the driving device must absorb all of the energy generated during the drive stroke and this subjects the device to an undesirable level of stress. It is also undesirable to actuate the driving mechanism when no fastener is in the drive track and the nosepiece is against the workpiece because the driving element typically extends out of the nosepiece when the driver is at the lowermost point of its power stroke so that the fastener can be driven flush or countersunk in the workpiece. Thus, if no fastener is present in the drive track, the driving element will mar the surface of the workpiece.
Power operated fastener driving devices typically include a trip assembly mounted on the nosepiece and operatively associated with the trigger mechanism to prevent the driving mechanism from being actuated when the nosepiece is not in contact with a workpiece. Typically, when the nosepiece is placed in contact with the workpiece, the trip assembly moves with respect to the workpiece and places the trigger mechanism in an active condition so that the driving mechanism can be actuated by movement of the trigger mechanism through its actuation stroke. Conventionally constructed trip assemblies do not prevent the driving mechanism from being actuated when the magazine is removed from the housing and/or the magazine is empty or nearly empty to prevent actuation of the driving mechanism when there is not fastener in the drive track, however, and this is a significant shortcoming of prior trip assembly design because it can result in damage to or marring of the surface of the workpiece. A need exists, therefore, for a power operated fastener driving device that cannot be actuated when the magazine is removed from the housing or when the magazine is empty or nearly empty.
Often the trip assemblies of fastener driving devices include adjustable mechanisms that can be adjusted to control the depth to which a fastener is driven into the workpiece. Typically these adjustments to a trip assembly require the use of hand tools and are time consuming to effect. A need exists for a trip assembly that can be easily adjusted manually without the use of hand tools to change the depth to which the fasteners are driven.
SUMMARY OF THE INVENTION
To meet these needs, the present invention provides a safety trip assembly that is easily manually adjusted without the use of hand tools to adjust the depth to which a fastener is driven into a workpiece. More specifically, the invention provides a fastener driving tool for driving fasteners into a workpiece that includes a housing assembly and a nosepiece assembly included in the housing assembly that defines a longitudinally-extending fastener drive track. A fastener driving mechanism carried internally of the housing assembly is constructed and arranged to drive a fastener through the fastener drive track and into a workpiece when the fastener drive mechanism is selectively activated by a user. A manually actuatable trigger mechanism is constructed and arranged to activate the fastener driving mechanism when manually actuated by a user.
A safety trip assembly is coupled to the housing assembly for longitudinal movement with respect to the nosepiece assembly. The safety trip assembly includes a trigger enabling portion and a workpiece engaging portion releasably coupled to the trigger enabling portion. The safety trip assembly is constructed and arranged to be movable between an extended position and a retracted position whereby the trigger enabling portion 1) enables the trigger mechanism to activate the fastener driving mechanism when manually actuated by a user when the safety trip assembly is in the retracted position and 2) disables the trigger mechanism when the safety trip assembly is not in the retracted position.
The safety trip assembly is constructed and arranged to be biased toward the extended position and to be moved toward the retracted position by engaging a longitudinal end of the workpiece engaging portion with a surface of a workpiece and pressing the housing assembly toward the workpiece, thereby moving the safety trip assembly against the bias with respect to the nosepiece assembly and a body portion of the housing assembly.
The safety trip assembly includes a releasable coupling mechanism for releasably coupling the trigger enabling portion to the workpiece engaging portion. The workpiece engaging portion of the safety trip assembly is constructed and arranged to be movable with respect to the trigger enabling portion when the workpiece engaging portion is uncoupled from the trigger enabling portion to permit adjustment of a longitudinal length of the safety trip assembly.
The releasable coupling mechanism includes fixed locking structure formed on an exterior portion of the workpiece engaging portion and a manually operable locking mechanism that is carried by the trigger enabling portion. The locking mechanism includes a locking member mounting structure rigidly attached to the trigger enabling portion adjacent the fixed locking structure formed on the workpiece engaging portion and a manually-operable, movable locking member mounted on the locking member mounting structure so as to be movable with respect thereto between a locking position and a releasing position. The movable locking member is constructed and arranged to engage the fixed locking structure when the movable locking member is in the locking position to interlock the movable locking member and the fixed locking structure to thereby prevent relative movement between the workpiece engaging portion and the trigger enabling portion and to disengage from the fixed locking structure when the movable locking member is in the releasing position to thereby permit relative movement between the workpiece engaging portion and the trigger enabling portion.
A locking member biasing mechanism is operatively associated with the movable locking member and is constructed and arranged to generate a biasing force to urge the movable locking member into its locking position. The movable locking member and the locking member biasing mechanism are constructed and arranged to permit the movable locking member to be manually moved against the biasing force by a hand of the user engaging the movable locking member to move the movable locking member from its locking position to its releasing position and to permit the movable locking member to automatically return to the locking positio
Pillsbury Madison & Sutro LLP
Smith Scott A.
Stanley Fastening Systems, LP
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