Tool with nosepiece for bending fastener upon installation and fastener therefor

#The present invention relates generally to fastener driving tools used for driving fasteners into workpieces to secure materials to the workpieces (referred to as workpiece materials), and specifically to fastener driving tools configured for driving two-legged fasteners, one example of such being referred to as a staple.

#Conventional fastener driving tools feature a reciprocating driver blade which impacts a fastener fed to a nosepiece by a magazine. Whether powered pneumatically, manually, by combustion or electricity, such tools provide sufficient force to the driver blade that it separates the fastener from adjacent fasteners in the magazine, and drives the fastener so that the fastener is sufficiently embedded in the workpiece.

#Commercially available two-legged fasteners include a pair of separated, generally parallel legs separated by a crown to form an inverted “U”-shape. Such fasteners are typically used in the installation of workpiece materials such as asphalt roofing shingles, building siding, wallboard, Romex® wire, Nomex® wire, Tyvek® insulation wrap, other insulation felts and other similar applications. One operational problem of two-legged fasteners is that the legs are sometimes driven too deeply into the workpiece, causing the crown to pierce the surface of the workpiece material. When this happens, the workpiece material is not as securely held. In other words, the amount of force needed to pull the workpiece material away from the workpiece (“pull through”) decreases when the workpiece material has been pierced. A side effect of this piercing is that the workpiece material may be damaged.

#FIG. 1 is a fragmentary front perspective view of a fastener driving tool featuring the present deformation formation;

#FIG. 2 is a fragmentary exploded view of the operation of the driver blade of the present tool upon the present fastener which is being driven into a workpiece;

#FIG. 3 is a front elevational view of the present fastener;

#Referring now to FIGS. 1 and 2, a fastener driving tool suitable for use with the present invention is generally designated 10 and includes a housing 12 enclosing a reciprocating driver blade 14, and a magazine 16 configured for providing a sequence of fasteners for driving. The tool 10 may be pneumatic, combustion-powered, manual, electrically-powered or powder activated, and a variety of such configurations of such tools are known in the art. Examples of such tools are sold under the trademark PASLODE® by Illinois Tool Works, Inc., the present assignee. A nosepiece 18 receives fasteners through a fastener opening 20, and is configured for positioning a next-to-be-driven fastener 22a for engagement by the descending driver blade 14.

#Referring now to FIGS. 2-4, the fastener preferred for use in the tool 10 is a two-legged fastener 22, in some cases known as a staple, having two legs 24, each leg having a point 26 shaped to pierce and become embedded in a workpiece 28 and joined together by a crown 30. In conventional staples, the crown is generally linear or straight, and the fastener forms an inverted “U”-shape. In an effort to increase the utility of two-legged fasteners, the present fastener 22 is provided with a crown 30 that is less likely to pierce or damage workpiece material 32 which is to be attached to the workpiece 28, and also which has relatively greater clamping force over the workpiece material 32 than standard inverted “U”-shaped fasteners. For the purposes of this discussion, the workpiece material 32 is intended to be attached to the workpiece or substrate 28, and the fastener legs 24 are configured, depending on the type of material, to either penetrate or avoid the material 32 and penetrate the substrate, while the crown 30 typically is designed to hold the material against the substrate.

#The present crown 30 includes a pair of shoulders 36 separated by a deformation portion 38. While it is contemplated that the deformation portion 38 may have a variety of shapes, as is discussed below, it is preferred that the portion defines a general “V” configuration which depends from the shoulders 36 and is generally coplanar with the fastener 22. As an alternative, and referring to FIG. 5, it is also contemplated that a fastener 39 may be provided to the tool 10 in a format in which, prior to driving, the deformation portion 38a projects at an angle to the plane of the fastener. As will be seen below, the deformation portion 38 provides enhanced clamping force over conventional staples, and, at the same time, reduces the possibility that the workpiece material 32 will be pierced or otherwise damaged in the fastener driving operation.