Elongated-member-driving apparatus – With means to move or guide member into driving position – Including supply magazine for constantly urged members
Reexamination Certificate
2000-08-11
2002-07-23
Smith, Scott A. (Department: 3721)
Elongated-member-driving apparatus
With means to move or guide member into driving position
Including supply magazine for constantly urged members
C227S008000, C227S136000, C227S138000
Reexamination Certificate
active
06422447
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to automatic fastening devices and, in particular, a fastening device that drives a fastener into a workpiece by effecting multiple blows upon the fastener. More specifically, the invention relates to a fastening device having a feed assembly operatively connected to a nose assembly for mechanically advancing the fastener into a fastener drive channel. Furthermore, the invention relates to a fastening device wherein a fastener drive channel has a guide surface adjacent the aperture of the nose assembly to direct the fastener as it is driven into the workpiece. The invention also relates to a fastening device having a releasable fastener assembly for releasably securing the nose assembly to the housing of the fastening device. The invention also relates to a fastening device having a control assembly for controlling the operation of the fastening device to conserve energy. Finally, the present invention relates to a coil of collated roofing nails wherein each of the nails is coated with a thermoplastic material that serves as a lubricant which facilitates driving of the nails. The coil of collated roofing nails is adapted for use with the fastening device.
BACKGROUND OF THE INVENTION
The most typical type of nailing or fastening device used to drive a fastener into a workpiece is that of the “single stroke” type. In these types of devices, a driver assembly is driven to fasten a fastener into a workpiece with single blow or impact. A disadvantage of these devices is that they require very high levels of impact energy, especially when longer fastener lengths are used.
There have been some attempts to provide a “multi-stroke” fastening device, which employs a striker assembly, which is driven to provide a plurality of blows or impacts upon the fastener head for progressively fastening the fastener into a workpiece. Such devices have been proposed by U.S. Pat. Nos. 1,767,485; 2,796,608; 3,203,610; 4,183,453; 4,724,992; and 4,807,793. The disadvantage with these proposed devices is that the fastener striker assembly is driven through a plurality of driving strokes, the lengths of the strokes are progressively increased as the fastener is progressively driven into the workpiece. As a result, the timing for driving the striker assembly becomes more difficult to manage. In addition, because the stroke length of the striker assembly increases during the course of each fastening cycle, the “feel” of the tool is somewhat irregular. Therefore, there is a need for a multi-stroke fastening device having a uniform stroke length.
Prior art fastening devices that drive a fastener into a workpiece with a single blow need not be concerned with the fastener driver maintaining a coupled relation with respect to the fastener being driven. Multi-blow fastening devices, on the other hand are presented with a unique problem in that if a plurality of fastening impacts are to be imparted upon a single fastener to drive the fastener into the workpiece, the tool tends to bounce off the fastener head with each drive stroke. This may lead to an inefficient and rather clumsy operation of the tool.
Typical multiple blow fastening devices are pneumatically operated, therefore there has been little concern to conserve power. A battery operated fastening device is a lot more mobile and requires less equipment and assembly to operate than pneumatically operated devices. Therefore, there is a need for a fastening device that is battery operated and is constructed and arranged to conserve power during a fastening operation.
Power fastening devices for driving nails into a workpiece come in a variety of types. The fasteners used in such fastening devices vary according to the application. Most fasteners are made from a steel material. It is known in the art that the diameter of the fastener shank has a bearing on the strength of the connection provided. Basically, the greater the shank diameter, the greater the securing function provided.
For certain applications, such as in, pneumatically operated framing nailers, it has been known that the framing nails can be coated with a thermoplastic material that partially liquifies while the nails are being driven and then acts as an adhesive when the thermoplastic again solidifies after the nails are driven into the workpiece.
The adhesive nature of the thermoplastic is advantageous for certain applications because it increases the strength of the connection without requiring enlargement of the metal shank diameter. An ancillary benefit to providing the thermoplastic coating is that it reduces the energy required to drive the nail into the workpiece.
A disadvantage of providing a thermoplastic coating onto fastening nails is that it significantly increases the cost of manufacture in comparison with the same nails that are not so coated.
Roofing nails, which typically have a shank diameter of about 0.120″±0.0015″ and a head diameter of about 0.350″-0.438″, are typically used to fastener shingles onto a roof. Heretofore, roofing nails have not been coated because the shank and head dimensions are sufficiently large to provide a relatively strong connection, particularly in light of the typically relatively soft shingle material that often tears before the nails would be pulled out. The cost of coating roofing nails has been considered to far outweigh any benefit to be gained.
Through experimentation with the unique fastening device described herein, applicants have recognized that in the particular application of a battery operated roofing fastener assembly, conservation of energy (i.e., battery life) is critical. Therefore, although roofing nails provide a more than adequate securement of shingles without the need for coating the same, and although thermoplastic coating significantly adds to the cost of manufacture, applicants have determined that the amount of increase in battery life results from providing coated roofing nails warrants the added cost for this particular application.
In order to remove jams and repair fastening devices, it is necessary to remove the nose assembly of the fastener assembly. Typically, the nose assembly is fastened to the housing and requires tools to disassemble, thus increasing downtime. Therefore, there is a need for a fastening device which facilitates quick and easy removal of the nose assembly to remove jams, thus reducing downtime.
Because the fasteners of fastening devices are typically collated by a flexible collation material, the leading fastener tends to pivot about the collation material, as the fastener is driven into the workpiece, until the collation fractures. Substantial movement can disorient the fastener in the drive track. This may cause the fastener to be deformed and/or driven into the workpiece incorrectly. Therefore, there is a need to adjust the orientation of the fastener while the fastener is being driven into the workpiece.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a multi-stroke fastening device for driving fasteners into a workpiece. This multi-stroke fastening device provides a housing, a fastener drive track carried by the housing, a striker assembly guide track mounted within the housing, a striker assembly mounted in slidable relation within said guide track, a power drive assembly, and a feed mechanism. The striker assembly includes a driver member constructed and arranged to strike a fastener disposed in the fastener drive track. The striker assembly is constructed and arranged to be moved along the guide track through a plurality of alternating drive strokes and return strokes to effect a plurality of impacts of the driver member upon the fastener in order to drive the fastener into the workpiece. The striker assembly has a substantially constant drive stroke length relative to the guide track. The power drive assembly is constructed and arranged to drive the striker assembly to effect the plurality of impacts of the driver member upon the fastener, and the feed mechanism is constructed a
Hewitt Charles W.
White Brian M.
Pillsbury & Winthrop LLP
Smith Scott A.
Stanley Fastening Systems, L.P.
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