The present invention relates generally to fastener driving tools such as combustion powered tools, pneumatic tools, cordless framing tools and the like. More particularly, the present invention relates to improvements in a device which adjusts the depth of drive of the tool.
As exemplified in Nikolich, U.S. Pat. Re. No. 32,452, and U.S. Pat. Nos. 4,552,162; 4,483,473; 4,483,474; 4,404,722; 5,197,646; 5,263,439; 5,558,264 and 5,678,899 all of which are incorporated by reference, fastening tools, and particularly, portable combustion powered tools for use in driving fasteners into workpieces are described. Such fastener-driving tools are available commercially from ITW-Paslode (a division of Illinois Tool Works, Inc.) of Vernon Hills, Ill., under the IMPULSE® brand.
Such tools incorporate a generally gun-shaped tool housing enclosing a small internal combustion engine. The engine is powered by a canister of pressurized fuel gas, also called a fuel cell. A battery-powered electronic power distribution unit produces the spark for ignition, and a fan located in the combustion chamber provides for both an efficient combustion within the chamber, and facilitates scavenging, including the exhaust of combustion by-products. The engine includes a reciprocating piston having an elongate, rigid driver blade disposed within a piston chamber of a cylinder body.
The wall of a combustion chamber is axially reciprocable about a valve sleeve and, through a linkage, moves to close the combustion chamber when a workpiece contact element at the end of a nosepiece connected to the linkage is pressed against a workpiece. This pressing action also triggers a fuel metering valve to introduce a specified volume of fuel gas into the closed combustion chamber from the fuel cell. The metering valve may take the form of a solenoid valve, which is powered by the battery, or may be a purely mechanical valve.
Upon the pulling of a trigger, which causes the ignition of a charge of gas in the combustion chamber of the engine, the piston and driver blade are shot downward to impact a positioned fastener and drive it into the workpiece. As the piston is driven downward, a displacement volume enclosed in the piston chamber below the piston is forced to exit through one or more exit ports provided at a lower end of the cylinder. After impact, the piston then returns to its original, or “ready” position through differential gas pressures within the cylinder. Fasteners are fed into the nosepiece from a supply assembly, such as a magazine, where they are held in a properly positioned orientation for receiving the impact of the driver blade. The power of the tools differs according to the length of the piston stroke, volume of the combustion chamber, fuel dosage and similar factors.
Combustion powered tools have been successfully applied to large workpieces requiring large fasteners, for framing, roofing and other heavy duty applications. Smaller workpiece and smaller fastener trim applications demand a different set of operational characteristics than the heavy-duty, “rough-in”, and other similar applications. Other types of fastener driving tools such as pneumatic, powder activated and/or electrically powered tools are well known in the art, and are also contemplated for use with the present adjustment mechanism.
One operational characteristic required in trim applications is the ability to predictably control fastener driving depth. For the sake of appearance, some trim applications require fasteners to be countersunk below the surface of the workpiece, others require the fasteners to be sunk flush with the surface of the workpiece, and some may require the fastener to stand off above the surface of the workpiece. Depth adjustment has been achieved in pneumatically powered and combustion powered tools through a tool controlling mechanism, referred to as a drive probe, that is movable in relation to the nosepiece of the tool. Its range of movement defines a range for fastener depth-of-drive. Similar depth of drive adjustment mechanisms are known for use in combustion type framing tools.
Existing depth adjusting mechanisms do have some drawbacks. One disadvantage of previous depth adjusting mechanisms is that they will only allow one speed of adjusting, usually gross adjustment. Many projects require the user to accurately set the depth of drive at a specific measurement. This can be difficult to accomplish when the adjusting mechanism only allows for gross adjustments, and therefore the user may have to adjust the depth of drive several times through trial and error in order to obtain the correct measurement for the depth of drive.
Consequently, one object of the present invention is to provide an improved depth of drive adjustment drive for use in a fastener driving tool, which allows the user to adjust the depth adjusting mechanism in either a fine or gross adjustment setting.
Another object of the present invention is to provide an improved depth of drive device for a fastener driving tool which allows for convenient and easy switching between fine and gross adjustments without releasing latches or other mechanisms.
Still another object of the present invention is to provide an improved depth of drive adjustment device for a fastener driving tool which is relatively inexpensive to manufacture and simple to assemble.
The above-listed objects are met or excluded by the present adjustable depth of drive device for use on a fastener driving tool, such as a combustion type framing tool or the like. An important feature of the present device is a spring loaded thumb wheel or barrel which is constructed and arranged to adjust the position of the workpiece contact element relative to the nosepiece so that either gross or fine adjustments may be made in virtually the same user motion, without the use of complicated latch mechanisms.
More specifically, the present invention provides an adjustable depth of drive device for use on a fastener driving tool having a housing structure which defines an axis, and encloses a combustion chamber, and a nosepiece which extends generally axially from the housing with a workpiece contact element. The device includes a thumb post which is mounted to, and extends from the workpiece contact element. A thumb wheel is adjustably engaged on the thumb post, and a spring member is engagable with the thumb wheel in at least two positions. In a first position, the spring member is frictionally engaged with the thumb wheel to prevent unwanted movement of the thumb wheel relative to the thumb post. In a second position, the spring member is disengaged from the thumb wheel to permit free rotation of the thumb wheel on the thumb post.
The spring member exerts a biasing force against the thumb wheel, and in the first position, the thumb wheel is manually movable when the biasing force is overcome, allowing for fine adjustments of the position of the work piece contact element relative to the nosepiece. Also, in the preferred embodiment, the spring member has a thumb lever for moving the spring member into the second position, allowing for gross adjustments of the position of the workpiece contacting element relative to the nosepiece.
As seen in
Referring now to
In the first position, the spring member 22 exerts a biasing force against the thumb wheel 20, and the thumb wheel is manually movable when the biasing force is overcome, allowing for fine adjustments of the position of the work piece contact element 16 relative to the nosepiece 14. It is an advantage of the present invention to allow a user to make fine adjustments to more accurately set the depth of drive without having to manually disengage the spring member 22, or any other extra latch member.
In both
In the preferred embodiment as seen in
The spring member 22 itself includes a plate 38 and a securing tab 40 that are disposed in a parallel, displaced relationship with respect to one another. Also included is at least one shoulder flange 42, which connects the plate 38 to both the thumb lever 24 and the securing tab 40. As seen in
Still referring to
Again referring to
Also in the preferred embodiment, as seen in
Referring now to
When the adjustable depth of drive device 10 is completely assembled and attached to the housing structure 12 as shown in
The present device allows the user to adjust the depth of drive with fine or slow adjustments by turning the thumb wheel 20 in either direction while the spring member 22 is exerting a biasing force against the thumb wheel. The user can adjust the depth of drive with gross, or faster adjustments by depressing the thumb lever 24, so that it is no longer in contact with the thumb wheel 20 which allows the thumb wheel to rotate freely. The user is allowed to adjust the depth of drive with the present invention when the fastening tool is in an actuated or non-actuated position.
While a particular embodiment of the adjustable depth of drive device of the invention has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.
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Number | Date | Country |
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0 298 594 | Jan 1989 | EP |
Number | Date | Country | |
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20020121540 A1 | Sep 2002 | US |