FASTENER DRIVING TOOL WITH IMPROVED
MAGAZINE AND FEED MECHANISM
The present invention relates to fastener driving de- 5 vices and more particularly to fastener driving devices of the type adapted to drive fasteners held in a plastic strip capable of being formed into a rolled or coiled package.
Devices of the type herein contemplated are exempli- 10 fied by the nailer tool disclosure in U.S. Pat. No. 3,543,987. U.S. Pat. No. 3,450,255 discloses a nail fastener package used with the device. Another example of a device as herein contemplated is the screw driving tool disclosed in U.S. Pat. No. 3,450,255. The screw 15 fastener package used with this device is disclosed in U.S. Pat. No. 3,885,669.
Still another device which exemplifies the devices herein contemplated is the combined impacting and turning tool disclosed in Japanese patent publication 20 No. 46991/82 published Oct. 6, 1982. A preferred bullet pointed screw fastener package for use with the impacting and turning tool is disclosed in commonly assigned U.S. application Ser. No. 704,476 now abandoned filed concurrently herewith. 25
The present invention is more particularly concerned with improving the driving action irrespective of the particular fastener being driven (i.e. whether a nail or a screw or a combination thereof). The present invention relates to the tool structure which handles the fastener 30 strip supporting the fasteners so as to enable the fasteners to be carried and driven in a more reliable fashion. Conversely, for the tool to achieve such reliability requires cooperation with a particular type of fastener plastic strip carrier. 35
A fastener plastic strip carrier of the type disclosed in U.S. Pat. No. 3,450,255 or 3,885,669 supports the fastener by a pair of hinged carrier tabs each having a fastener receiving slot which allows the fastener to be stripped laterally therefrom during the driving move- 40 ment. As the fastener head moves downwardly during the driving movement, the tabs are engaged and hinged downwardly. The action is such that as the fastener is driven, a transverse pull is imposed upon the fastener shank so that its pointed end may be moved in the drive 45 track in an inclined position. If the size of the slot is enlarged so as to reduce the pull, the fastener has a greater tendency to be accidentally stripped from the carrier in the tool magazine or elsewhere.
The strip feeding mechanism in the tool using the 50 hinged tab plastic strip is constructed to have a pawl member which engages a portion of the strip to push and feed the strip forwardly. The strip is subject to being deformed since it is usually made of a thin plastic sheet. In some instances, the strip is deformed so far as 55 to fail to engage with the pawl member thereby to cease its supply, thus raising a serious defect that the strip is not supplied reliably.
It is an object of the present invention to provide a tool which will obviate the disadvantages noted above. 60 In accordance with the principles of the present invention the tool of the present invention preferably utilizes a coiled fastener package of the type disclosed in the aforesaid application which includes a multiplicity of fasteners supported in vertically extending parallel row 65 formation by a horizontally elongated thin walled plastic carrier strip. The carrier strip includes a series of longitudinally spaced pairs of upper and lower fastener
retaining walls, each pair of upper and lower walls extending generally horizontally and being disposed in generally vertical spaced parallel relation with respect to one another, a vertical wall connected between one pair of corresponding edges of each pair of upper and lower walls, the lower walls being longitudinally interconnected at their edges opposite from the one edge, and a continuous wall longitudinally interconnecting the upper walls at their edges opposite from the one edge. The continuous wall extends vertically downwardly from the opposite edges of the upper walls and terminates in a lower edge forming a continuous longitudinally extending gap therebelow and above the interconnected opposite edges of the lower walls. The upper and lower walls have longitudinally spaced aligned pairs of openings formed in central areas thereof configured to releasably support the fasteners with their axes extending vertically in a parallel row formation with respect to one another in such a way that each fastener including the head thereof can be moved a'xially from the pair of walls supporting the same without substantially unbalanced transverse forces being applied thereto. The lower edge of the continuous wall has a multiplicity of feeding notches therein opening into the gap spaced apart a longitudinal distance generally equal to the longitudinal spacing between fasteners.
In accordance with the principles of the present invention the tool includes a tool body defining a fastener drive track, a fastener driving element mounted in the drive track for movement through successive operative cycles each including a providing interior space for retaining a coiled carrier strip with supported fasteners, a guide passage leading from the magazine to the drive track along which a leading end portion of the strip with supported fasteners can be moved, and a fastener feeding mechanism for moving the leading end portion of the strip with fasteners along the guide passage. The feeding mechanism includes an L-shaped member having a horizontally extending portion and a vertical portion extending upwardly therefrom. The L-shaped member is disposed with respect to the guide passage such that the horizontal extending portion extends through the gap in the strip and the vertically extending portion extends alongside the inner surface of the continuous wall of the strip. The feeding mechanism also includes a feeding pawl mounted for movement through successive operative cycles each of which includes a feed stroke and a return stroke, and a piston and cylinder unit for effecting movement of the pawl such that the same will be engaged within a strip notch at the end of each return stroke so that the strip will be moved with the pawl during the drive stroke thereof.
Another difficulty with prior art tools of the type described arises from the fact that fasteners used with tools of this kind have several different lengths according to their applications. Therefore, in order to move these fasteners out of the magazine toward the supply passage, the magazine is required to be equipped with some adjusting means to accommodate the different lengths of the fasteners. Each time a different kind of fastener is used, the adjusting means must be readjusted in a complicated manner.
Accordingly another object of the present invention is to alleviate the problems of magazine adjustment noted above. In accordance with the principles of the present invention this objective is obtained by providing a magazine which includes a fixed section and a movable section mounted with respect to the fixed sec