Patent Application
20070057006
The present invention relates generally to fastener-driving tools used to drive fasteners into workpieces, and specifically to pneumatically powered fastener-driving tools, also referred to as pneumatic tools. More particularly, the present invention relates to improvements in a device or assembly which adjusts the depth of drive of the tool. Other types of fastener driving tools such as combustion, powder activated and/or electrically powered tools are well known in the art, and are also contemplated for use with the present depth of drive adjustment assembly. The use of “fastener driving tools” in this application is considered to encompass all such tools, suitable examples of which are sold under the PASLODE brand manufactured by Illinois Tool Works, Vernon Hills, Ill.
Power fastener-driving tools of the type used to drive nails, staples and other types of fasteners typically include a housing, a power source, a supply of fasteners, a trigger for operating the power mechanism and a workpiece contacting element. The latter component is typically reciprocally slidable relative to the housing and connected to the trigger mechanism in some way, so that the fastener will not be driven unless the tool is pressed against a workpiece. Examples of such a prior fastener-driving tool is disclosed in U.S. Pat. Nos. 4,629,106 and 6,543,664, which are incorporated by reference.
One operational characteristic required in fastener driving applications, particularly 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.
A conventional arrangement for depth adjustment involves the use of respective overlapping plates or tongues of a workpiece contact element and a wire form or valve linkage. At least one of the plates is slotted for sliding relative length adjustment. Threaded fasteners such as cap screws are employed to releasably secure the relative position of the plates together. The depth of fastener drive is adjusted by changing the length of the workpiece contact element relative to the wire form. Once the desired depth is achieved, the fasteners are tightened.
It has been found that users of such tools are inconvenienced by the requirement for an Allen wrench, nut driver, screwdriver or comparable tool for loosening the fasteners, then retightening them after length adjustment has been completed. In operation, it has been found that the extreme shock forces generated during fastener driving cause the desired and selected length adjustment to loosen and vary. Thus, the fasteners must be monitored for tightness during tool use.
To address the problem of maintaining adjustment, grooves or checkering have been added to the opposing faces of the overlapping plates to increase adhesion when the fasteners are tightened. However, to maintain the strength of the components in the stressful fastener driving environment, the grooves have not been made sufficiently deep to provide the desired amount of adhesion. Deeper grooves could be achieved without weakening the components by making the plates thicker, but that would add weight to the linkage, which is undesirable.
In other conventional tools, a fluted, threaded barrel is threadably engaged with a threaded end of a wire form workpiece contact element. Rotation of the fluted barrel adjusts the depth of drive. A biased, locking mechanism engages the flute to maintain position. In operation, impact forces have been known to cause unwanted movement of the barrel, changing the depth adjustment.
Other attempts have been made to provide tool-less depth of drive adjustment, but they have also employed the above-described opposing face grooves for additional adhesion, which is still prone to the adhesion problems discussed above.
Another design factor of such depth adjustment or depth of drive (used interchangeably) mechanisms is that the workpiece contact elements are often replaced over the life of the tool. As such, the depth adjustment mechanism preferably accommodates such replacement while retaining compatibility with the wire form, which is not necessarily replaced.
Accordingly, there is a need for a fastener driving tool depth of drive adjustment device or assembly where the adjustment is secured without the use of tools and is maintained during extended periods of fastener driving. There is also a need for a fastener depth adjustment device or assembly which provides for more positive retention of the relative position of the workpiece contact element without reducing component strength.
The above-listed needs are met or exceeded by the present tool-less depth adjustment assembly for a fastener-driving tool which overcomes the limitations of the current technology. Among other things, the present assembly is designed for more securely retaining the workpiece contact element relative to a wire form linkage during tool operation, while at the same time providing adjustability by the user without the use of tools.
More specifically, an adjustable depth of drive assembly for use with a fastener driving tool is provided and includes a workpiece contact element having a contact end and an adjustment end, a rotatable adjustment member configured for being securable to the tool and being displaceable between an adjustment position in which the workpiece contact element is movable relative to the tool, and a locked position where the adjustment end is non-movable relative to the tool. The rotatable adjustment member engages the adjustment end whereby rotation of the rotatable adjustment member causes movement of the workpiece contact element relative to the tool. Further, at least one locking detent is disposed on the rotatable adjustment member and configured for being reciprocally engaged and disengaged from at least one locating hole by manually overcoming a spring bias to displace the rotatable adjustment member from the locked position to the adjustment position. The adjustment position permits the securing of the adjustment end in a selected locked position relative to the housing without the use of tools.
In a preferred embodiment, a locking member is disposed on the tool and has a locating structure disposed thereon. A spring is configured to axially bias the rotatable adjustment member towards the locking member. Disposed on the rotatable adjustment member is at least one locking detent configured to engage the locating structure in the locked position, and to disengage from the locating structure in the adjustment position when the spring bias is overcome.
Referring now to
Extending from the housing 14 is a nosepiece 22 configured for receiving fasteners from a magazine 24, also as is well known in the art. A workpiece contact element 26 is configured for reciprocal sliding movement relative to the nosepiece 22 and, in the preferred embodiment, surrounds the nosepiece on at least three sides. The present depth of drive assembly 10 is configured for adjusting the relative position of the workpiece contact element 26 to the upper work contact element 16, which in turn alters the relative position of the workpiece contact element to the nosepiece 22. Generally speaking, as the nosepiece 22 is brought closer to the workpiece surface, fasteners driven by the tool 12 are driven deeper into the workpiece.
An adjustment end 28 of the workpiece contact element 26 is preferably threaded (See
Referring now to
A locking member 38 is disposed on the tool, preferably integral with the central portion 18. The locking member 38 preferably includes two opposing legs 40, extending transversely from the central portion 18, and defining a rotating space therebetween. Preferably located on each opposing leg 40 is a throughbore 42 which is generally linearly aligned with the throughbore 42 on the opposite leg (
Referring to
On a top, exterior surface 48 of the rotatable adjustment member 34, at least one locking detent 50 is preferably disposed. Preferably a raised formation, the locking detent 50 is preferably non-resilient. Further, preferably both the locking detent 50 and the rotatable adjustment member 34 are made of stainless steel. In the preferred embodiment, two locking detents 50 are disposed generally 180-degrees apart, but other numbers and arrangements of locking detents 50 are contemplated. Further, other materials, shapes and sizes of locking detents are contemplated.
Now referring to
In
As will be explained in further detail below, the rotatable adjustment member 34 is securable to the tool 12 and is movable between the adjustment position, in which the workpiece contact element 26 is movable relative to the tool 12, and the locked position where the adjustment end 28 is secured to the tool. A feature of the present system 10 is that the displacement of the rotatable adjustment member 34, and the associated locking compression spring 60, between the adjusting position and the locking position, is accomplished without the use of tools.
When the rotatable adjustment member 34 is disposed between the opposing ends 40, an internally threaded hollow or tubular pin 68 is inserted up through the internal wall 62. Concentric with the threaded pin 68, the rotatable adjustment member 34 is maintained between the opposing legs 40 by the insertion of the threaded pin 68 through the throughbore 42 of each opposing leg.
The threaded pin 68 is preferably pressure fit with the rotatable adjustment member 34. Preferably constructed of mild carbon steel, the threaded pin 68 is fixed relative to the rotatable adjustment member 34, to rotate with the rotatable adjustment member. While in the preferred embodiment the threaded pin 68 is a separate piece from the rotatable adjustment member 24, a one-piece rotatable adjustment member 34 with a threaded interior is contemplated. The threaded pin 68 preferably extends through each throughbore 66 of the opposing ends 40, however other configurations that permit the rotation of the pin and the adjustment member 34 are contemplated.
Inside the threaded pin 68, a threaded interior surface 70 is configured to receive the adjustment end 28 of the workpiece contact element 26. When the rotatable adjustment member 34 is rotated, and thus the threaded pin 68 is rotated with the adjustment member, the threaded surface 70 acts on the adjustment end of the workpiece contact element 26. Depending on the direction of threads, rotation of the adjustment member 34 in one direction causes the workpiece contact element 26 to displace upwards, while rotation of the adjustment member 34 in the opposite direction causes the workpiece contact element to displace downwards.
On the locking member 38, preferably at the opposing leg 40 adjacent the top surface 48 of the rotatable adjustment member 34, is at least one locating structure 72. Preferably holes punched into the opposing leg 40 having generally the same dimensions as the locking detent 50, the locating structure 72 is configured to positively receive the locking detent.
When the locking detents 50 are disposed in the locating structure 68, the rotatable adjustment member 34 is in a locked position, prevented from movement.
To move the rotatable adjustment member 34 to an adjustment position, the axially directed spring bias must be overcome by axially displacing the adjustment member away from the opposing leg 40. As the rotatable adjustment member 34 is displaced away from the opposing leg 40, the detents 50 disengage from the locating structure 72. When the detents 50 are disengaged, the adjustment member 34 is freely rotatable and, as a result of the rotation, the workpiece contact element 26 displaces up or down in the threaded pin 68.
In the locked position, the workpiece contact element 26 cannot move axially relative to the rotatable adjustment member 34, thus maintaining the desired depth of drive adjustment, even during the stressful environment of repeated actuation (for non-combustion tools) or combustion events, which is known to cause structural stresses on the workpiece contact element 26. It will be seen that the length of the threaded pin 68 and the adjustment end 28 of the workpiece contact element 26 allows the workpiece contact element to be adjusted axially relative to the rotatable adjustment member 34 to achieve a variety of depth adjustment positions to account for a variety of workpiece situations and length of fasteners.
Additionally, it is contemplated that the locked position of the rotatable adjustment member 34 may be manually overridden. Depending on the compression strength of the compression spring 60, the user is able to manually override the locking member 38 by rotating the adjustment member 24 out of engagement with the locating structure 68 without first displacing the member away from the opposing leg 40. In this configuration, the user is able to rotate the adjustment member 24 against the bias of the compression spring 60 until the detent 50 engaged in the locating structure 68. This provides small incremental rotations, or “fine-adjustment,” of the depth of drive assembly 10.
While a particular embodiment of the present tool-less depth adjustment for a fastener-driving tool has been described herein, 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.
