Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
1998-09-11
2001-02-13
Scherbel, David A. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C081S057370, C081S435000
Reexamination Certificate
active
06186035
ABSTRACT:
The present invention relates to power-operated screwdriving devices.
Conventional power-operated devices having feeding mechanisms which feed subsequent collated screws into a drive track automatically in response to operation of the device. Some of these devices utilize a pawl or tooth which engages the underside of a subsequent lead screw, or the collation itself just beneath the subsequent lead screw. Movement of the pawl towards the drive track moves the subsequent lead screw into the drive track wherein it can be drive into a workpiece. An example of such a device is shown in U.S. Pat. No. 5,568,753.
One problem with the device of the '753 patent is the complexity of the feeding mechanism. In particular, the device of the '753 patent requires two small torsion springs to properly feed the screws. One of the spring moves the shuttle in the feeding direction and the other spring bias the feed pawl into engagement with the collation. Also, the shuttle requires a guiding track to guide its movement in the feeding direction. Assembling all of these individual components can be rather complex and increases manufacturing difficulties and cost.
It is therefore an object of the present invention to provide screwdriving device having a simplified yet functionally effective feeding mechanism. Thus, in accordance with the principles of the present invention there is provided a screwdriving device configured to be used with a rotary power source and a screw collation supply. The screw collation supply including a supply of screws releaseably mounted on a collation. The screwdriving device comprises a housing structure constructed and arranged to be engaged with the rotary power source. A feeding assembly defines a drive track constructed and arranged to receive a lead screw from the screw collation supply. A rotatable screw engaging bit member is constructed and arranged to be operatively connected with the rotary power source such that the rotary power source can rotate the rotatable screw engaging bit member during a screwdriving operation wherein the lead screw is driven into a workpiece.
The bit member is engageable with the lead screw and movable relative to the drive track such that rotation of the bit member and relative movement between the bit member and the drive track drives the lead screw into the workpiece during the screwdriving operation. The feeding assembly is constructed and arranged to move a subsequent lead screw from the screw collation supply into the drive track in a feeding direction and to move emptied portions of the collation outwardly from the drive track after driving the lead screw into the workpiece during the screwdriving operation. The feeding assembly includes a screw feeding structure movable between (1) a lead screw engaged position wherein the screw feeding structure engages the screw collation supply adjacent the lead screw so as to prevent the lead screw from is removed from the drive track in a removal direction opposite the feeding direction and (2) a subsequent lead screw engaging position wherein the screw feeding structure engages the screw collation supply adjacent the subsequent lead screw.
The feeding assembly includes a biasing element engaged with the screw feeding structure. The biasing element is positioned and configured such that the biasing element applies a biasing force to the screw feeding structure in the feeding direction so as to (1) bias the screw feeding structure from the subsequent lead screw engaging position towards the lead screw engaging position and (2) bias the screw feeding structure towards and into engagement with the screw collation supply. The feeding assembly is constructed and arranged such that the screw feeding structure moves against the biasing force of the biasing element from the lead screw engaging position to the subsequent lead screw engaging position in response to the bit member moving forwardly relative to the drive track during the screwdriving operation. The screw feeding structure engages the exterior surface of the subsequent lead screw so as to move against the biasing force of the biasing element away from the screw collation supply as the screw feeding structure moves from the lead screw engaging position to the subsequent lead screw engaging position, and then, after the screw feeding structure has cleared the subsequent lead screw, the biasing element applies the biasing force so as to move the screw feeding structure towards the screw collation supply and into the subsequent lead screw engaging position. The feeding assembly is constructed and arranged such that the biasing element moves the screw feeding structure from the subsequent lead screw engaging position to the lead screw engaging position in response to the bit member moving rearwardly relative to the drive track after the screwdriving operation so as to move the subsequent lead screw into the drive track.
Also, in conventional screwdriving devices the feeding pawl or tooth oftentimes engages and supports the screw in the drive track such that the operator cannot pull the collation so as to pull the screw out of the drive track opposite the feeding direction. One problem which occurs with such an arrangement arises in the event of jams or when debris enters the drive track. When such a situation arises, it is desirable to be able to clear the drive track and removing the screw from the drive track makes the task easier. However, the pawl engaged beneath the screw prevents the operator from removing the screw from the drive track simply by pulling the screw collation opposite the direction in which it was fed. Thus, the operator must cut the screw free from the collation or try to work around the screw while clearing the debris or jam.
It is therefore an object of the present invention to provide a screwdriving device from which the collated screws can be easily and quickly removed in order to facilitate the clearance of jams and debris. Thus, in accordance with the principles of the present invention there is provided a power-operated screwdriving device configured to be used with a rotary power source and a supply of screws releasably mounted on a collation. The screwdriving device comprises a housing structure constructed and arranged to be engaged with the rotary power source. A feeding assembly defines a drive track constructed and arranged to receive a lead screw from the supply of screws and a lead screw portion of the collation. The lead screw is releasably mounted on the lead screw portion of the collation. A rotatable screw engaging bit member is constructed and arranged to be operatively connected with the rotary power source such that the rotary power source can rotate the rotatable screw engaging bit member during a screwdriving operation wherein the lead screw is driven into a workpiece.
The rotatable screw engaging bit member is engageable with the lead screw and movable relative to the drive track such that rotation of the screw engaging bit member and relative movement between the screw engaging bit member and the drive track separates the lead screw from the lead screw portion of the collation and drives the lead screw into the workpiece during the screwdriving operation. The feeding assembly includes a screw feeding structure constructed and arranged to move a subsequent lead screw in a screw feeding direction into the drive track and to move the lead screw portion of the collation outwardly from the drive track after the lead screw has been driven into the workpiece during the screwdriving operation.
The screw feeding structure is movable between (1) a lead screw engaged position wherein the screw feeding structure engages one of the lead screw received in the drive track and the lead screw portion of the collation so as to prevent the lead screw and the lead screw portion from moving out of the drive track in a screw removal direction opposite the screw feeding direction and (2) a lead screw disengaged position wherein the screw feeding structure is disengaged from the lead screw received in the
Buzzeo David J.
Jalbert David B.
Russell James A.
McDonald Shantese
Pillsbury Madison & Sutro LLP
Scherbel David A.
Stanley Fastening Systems, L.P.
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