Safety trip assembly and trip lock mechanism for a fastener driving tool

Abstract

A fastener driving tool includes a housing assembly with a nosepiece assembly defining a drive track. A driving mechanism is housed within the housing assembly to drive a fastener through the drive track and into a workpiece in response to a trigger. The tool includes a safety trip assembly which includes a trigger enabling portion and a workpiece engaging portion and is movable between an extended disabling position and a retracted enabling position. The safety trip assembly is biased toward the extended position and is moved toward the retracted position by engagement between the workpiece and the workpiece engaging member. The workpiece engaging portion is movable to permit adjustment of a length of the safety trip assembly. The safety trip assembly includes a coupling mechanism including a fixed locking structure formed on an exterior portion of the workpiece engaging portion and a manually operable locking mechanism. The locking mechanism is carried by the trigger enabling portion and includes a locking member mounting structure and has a manually operable locking member mounted thereon. The movable locking member is biased into a locking position, engaging the fixed locking structure and preventing relative movement between the workpiece engaging portion and the trigger enabling portion and may move into a releasing portion disengaging the fixed locking structure and permitting such relative movement. A user may manually move the locking mechanism against the bias by engaging the movable locking member and moving it from the locking position to the releasing position.

Description

[0001]This application claims benefit to provisional application Ser. No. 60 / 127,836 filed Apr. 5, 1999.BACKGROUND OF THE INVENTION[0002]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.[0003]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 fas...

AI Technical Summary

Benefits of technology

[0007]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.

[0011]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.

[0016]The fastener feeding mechanism is constructed and arranged to engage the trip lock mechanism when the fastener supply channel is empty to move the fastener lock member from the neutral orientation to the locking orientation to prevent the trigger mechanism from being activated when the fastener supply channel is empty.

Problems solved by technology

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 drive 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.

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.

Typically these adjustments to a trip assembly require the use of hand tools and are time consuming to effect.

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