Patent Application
20100213234
This invention relates to the field of devices used to drive fasteners into work pieces and particularly to a device for impacting fasteners into work pieces.
Fasteners such as nails and staples are commonly used in projects ranging from crafts to building construction. While manually driving such fasteners into a work piece is effective, a user may quickly become fatigued when involved in projects requiring a large number of fasteners and/or large fasteners. Moreover, proper driving of larger fasteners into a work piece frequently requires more than a single impact from a manual tool.
In response to the shortcomings of manual driving tools, power-assisted devices for driving fasteners into wood and other materials have been developed. Contractors and homeowners commonly use such devices for driving fasteners ranging from brad nails used in small projects to common nails which are used in framing and other construction projects. Compressed air has been traditionally used to provide power for the power-assisted devices. Specifically, a source of compressed air is used to actuate a piston assembly which impacts a nail into the work-piece.
In addition to driving fasteners, however, manual impacting devices are frequently used to move or adjust the position of a work piece prior to fastening the work piece. This practice is particularly common in stick framing where wood may be misaligned for a number of different reasons. In such situations, a user taps or strikes the work piece with a hammer until the work piece is properly aligned. The aligned work piece is then fastened in position. With the onset of pneumatic nailers, manual impacting devices are not always readily available. Accordingly, rather than climbing down from a work site and retrieving a hammer, many users simply use the pneumatic device as a manual impacting device. Since most pneumatic devices include a substantial amount of metal, users generally believe the pneumatic device to be able to withstand the manual impacting forces.
The top of a pneumatic nailer is typically somewhat flat and can be used as a manual impacting tool without exposing the hands of the user to the impact. Thus, users frequently use the top portion of the pneumatic tool housing as an impacting surface. The housing of pneumatic tools, however, is not commonly designed to withstand impacting forces. For example, pneumatic nailers are typically vented through the top of the device. In order to prevent blowing air into the face of the user, a deflector is positioned on the top of the pneumatic nailer to direct the vented air away from the user. The deflector may be mounted to the upper housing of the tool or the deflector may be formed integrally with the device housing.
In either event, the deflector, which is inherently weaker than other parts of the pneumatic nailer housing, is the part of the pneumatic nailer most frequently used as an impacting device. Thus, while repeated impacts can result in damage to various part of the tool and parts of the tool may even break off, the deflector is one of the most frequently damaged components of a pneumatic nailer.
What is needed is a device incorporating an element which can be used to absorb energy from an impact. What is further needed is a device incorporating an element which is simple, reliable, lightweight, and compact. A further need exists for a device that incorporates an energy absorbing element that has a long useful lifetime and that does not require extensive redesign of the device.
In accordance with one embodiment, there is provided a device for impacting a fastener that includes a housing with an upper housing portion, a middle housing portion, and a side housing portion extending between the upper housing portion and the middle housing portion, a drive cylinder configured to vent within the housing, an air passage extending through the housing and including a mouth at the upper housing portion, and a strike plate extending over the upper housing portion and including a top portion positioned apart from the upper housing portion, and a first side extension extending downwardly from the top portion along the side housing portion to a location above and spaced apart from an outwardly extending first surface of the middle housing portion.
In accordance with another embodiment, there is provided a device for impacting a fastener including a housing with an upper housing portion, a middle housing portion, and a side housing portion extending between the upper housing portion and the middle housing portion, a drive cylinder configured to vent within the housing, an air passage extending through the housing and configured to vent the housing, a strike plate extending over the upper housing portion and including a top portion, and a first side extension extending downwardly from the top portion along the side housing portion to a location above and spaced apart from an outwardly extending first surface of the middle housing portion, and a gasket positioned between the upper housing portion and the top portion of the strike plate.
In accordance with a further embodiment, a device for impacting a fastener includes a housing including an upper housing and a lower housing, a drive cylinder positioned within the housing and configured to vent into the housing, an air passage extending from within the housing to without the housing, a strike plate including a top surface positioned above the upper housing, and a first side extension extending downwardly from the top surface toward the lower housing to a location above and spaced apart from a horizontal surface of the upper housing, and a gasket positioned between the top of the upper housing and the top surface of the strike plate.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains.
The fastener cartridge 104 in this embodiment is spring biased to force fasteners, such as nails or staples, serially one after the other, into a loaded position adjacent a drive section 120, shown in
The strike plate 118, shown in additional detail in
The fastener well 152 of the strike plate 118 is positioned within a fastener well 158 of the upper housing 108. A fastener bore 160 is located at a lower portion of the well 152. A gasket 164 extends along the housing 108. A cup 166 is located within the fastener well 152 and includes a lip 168 that extends downwardly through the fastener bore 160 to a location adjacent the gasket 164 and abutting the housing 108. The fastener 148 clamps the cup 166 against the fastener well 152 and against the housing 108. The gasket 164 is formed to maintain a passage 170 between the upper housing 108 and the underside 172 of the top surface 140 between a vent 174 and the atmosphere. The vent 174 provides an air passage venting the interior of the housing 102 to atmosphere. Additional vents and passages may be provided.
If desired, the gasket 164 may be formed to extend between the upper housing 108 and the strike plate 118 along the two extensions 142 and 144. Moreover,
Returning to
With reference to
Movement of the strike plate 118 results in compression of the gasket 164 against the upper housing 108. In one embodiment, the gasket 164 is formed using a urethane material. Other materials that may be used as a gasket material include natural rubber and microcellular polyurethane elastomer (MPE). MPEs form a material with numerous randomly oriented air chambers. Some of the air chambers are closed and some are linked. Additionally, the linked air chambers have varying degrees of communication between the chambers and the orientation of the linked chambers varies. Accordingly, when the MPE structure is compressed, air in the chambers is compressed. As the air is compressed, some of the air remains within various chambers, some of the air migrates between other chambers and some of the air is expelled from the structure. MPEs thus exhibit good impact absorbing characteristics. One such MPE is MH 24-65, commercially available from Elastogran GmbH under the trade name CELLASTO®.
As the gasket 164 is compressed, some of the impact force is absorbed. Additionally, because the strike plate 118 is relatively stiff, the impact force transmitted to the gasket 164 is not concentrated at a small area of the gasket 164. Accordingly, any force acting through the top of the upper housing 108 is spread over a large surface area of the upper housing 108.
Additionally, as the strike plate 118 is forced toward the upper housing 108, the extensions 142 and 144 move closer to the flange 180, narrowing the gap between the base portions 190 and 192 and the channel bottoms 186 and 194. In this embodiment, the thickness of the gasket 164 is selected to be slightly less than the initial gap between the base portions 190 and 192 and the channel bottoms 186 and 194. Accordingly, as the gasket 164 approaches full compression, the base portions 190 and 192 contact the channel bottoms 186 and 194, respectively. Accordingly, any residual energy is transferred directly from the base portions 190 and 192 to the channel bottoms 186 and 194.
The lower portion 182 of the upper housing 108 is relatively thick and is thus able to absorb increased amounts of force. Moreover, because the ledge 188 is positioned directly in line with an upper surface of the lower housing 106, force is readily transmitted into the lower housing 106. Depending upon the particular materials and design, the foregoing sequence of events may differ. Accordingly, by varying the thickness of the gasket 164 and the gap between the base portions 190 and 192 and the channel bottoms 186 and 194, along with selection of specific materials for the strike plate 118 and the gasket 164, selective amounts of impact force may be directed away from the top of the housing 108.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the invention are desired to be protected.
