Tool-less rotatable depth adjustment for fastener-driving tool

An adjustable depth of drive assembly for use with a fastener driving tool 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 adjusting position in which the workpiece contact element is movable relative to the tool and a locked position wherein the adjustment end is non-movable relative to the tool, and at least one locking detent being reciprocally engaged and disengaged from at least one locating hole by manually overcoming a spring bias to displace the rotatable member from said locked position to said adjustment position for securing said adjustment end in a selected locked position relative to said housing without the use of tools.

BACKGROUND OF THE INVENTION

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 are disclosed in U.S. Pat. Nos. 4,629,106 and 6,543,664, which are incorporated by reference. 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.

BRIEF SUMMARY OF THE INVENTION

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.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIG. 1, an improved adjustable depth of drive assembly is generally designated10, and is intended for use on a fastener driving tool of the type described above, and generally designated12. The tool12includes a housing14enclosing a combustion chamber (not shown) and a reciprocating valve sleeve (not shown) connected to an upper work contact element16, including a central portion18and an elongate arm20which is connected at the free end to the valve sleeve as is known in the art. In the preferred embodiment, the upper work contact element16and the central portion18are fabricated by being stamped and formed in single piece of metal, however other rigid durable materials and fabrication techniques are contemplated.

Extending from the housing14is a nosepiece22configured for receiving fasteners from a magazine24, also as is well known in the art. A workpiece contact element26is configured for reciprocal sliding movement relative to the nosepiece22and, in the preferred embodiment, surrounds the nosepiece on at least three sides. The present depth of drive assembly10is configured for adjusting the relative position of the workpiece contact element26to the upper work contact element16, which in turn alters the relative position of the workpiece contact element to the nosepiece22. Generally speaking, as the nosepiece22is brought closer to the workpiece surface, fasteners driven by the tool12are driven deeper into the workpiece.

An adjustment end28of the workpiece contact element26is preferably threaded (SeeFIG. 5). Opposite the adjustment end28, a contact end30is configured to contact a workpiece surface into which the fastener is to be driven, as is known in the art. In a preferred embodiment, the contact end30has a contact shield32disposed over the workpiece contact element26. The contact shield32preferably extends under the contact end30and over three sides of the workpiece contact element26to contact the workpiece surface.

Referring now toFIGS. 1 and 2, the present depth of drive assembly10extends generally coaxially with the nosepiece22and the workpiece contact element26has a generally elongate “U”-shape. The depth of drive assembly10includes a rotatable adjustment member34configured for engaging the adjustment end28of the workpiece contact element26and securing the same relative to the tool12. Preferably, the central portion18is secured to the tool12and the rotatable adjustment member34is secured to the central portion, as described below. While the central portion18is preferably integral with the elongate arm20, other configurations are contemplated.

A locking member38is disposed on the tool, preferably integral with the central portion18. The locking member38preferably includes two opposing legs40, extending transversely from the central portion18, and defining a rotating space therebetween. Preferably located on each opposing leg40is a throughbore42which is generally linearly aligned with the throughbore42on the opposite leg (FIG. 5).

Referring toFIG. 3, the rotatable adjustment member34is generally cylindrical and preferably has a gripping formation44, such as corrugations or flutes, on a generally circular, exterior surface46. The gripping formation44is the surface where the user contacts the adjustment member34to manually rotate the adjustment member with respect to the tool12.

On a top, exterior surface48of the rotatable adjustment member34, at least one locking detent50is preferably disposed. Preferably a raised formation, the locking detent50is preferably non-resilient. Further, preferably both the locking detent50and the rotatable adjustment member34are made of stainless steel. In the preferred embodiment, two locking detents50are disposed generally 180-degrees apart, but other numbers and arrangements of locking detents50are contemplated. Further, other materials, shapes and sizes of locking detents are contemplated.

Now referring toFIGS. 4 and 5, a bottom, exterior surface52of the rotatable adjustment member34has an inner diameter portion54and an outer diameter portion56. Disposed between the inner diameter portion54and the outer diameter portion56is a compression spring pocket58. A compression spring60(SeeFIG. 5) is inserted into the compression spring pocket58to be located between an internal wall62and an external wall64. When the compression spring60is not compressed, the spring protrudes from the compression spring pocket58.

InFIGS. 3-5, the internal wall62preferably defines a throughbore66. When the rotatable adjustment member34is disposed between the two opposing legs40of the locking member38, the throughbore42of each opposing leg lines up with the throughbore66of the rotatable adjustment member. Further, the top, exterior surface48of the rotatable adjustment member34is biased towards one of the opposing legs40, while the compression spring60pushes against the other of the opposing legs.

As will be explained in further detail below, the rotatable adjustment member34is securable to the tool12and is movable between the adjustment position, in which the workpiece contact element26is movable relative to the tool12, and the locked position where the adjustment end28is secured to the tool. A feature of the present system10is that the displacement of the rotatable adjustment member34, and the associated locking compression spring60, between the adjusting position and the locking position, is accomplished without the use of tools.

When the rotatable adjustment member34is disposed between the opposing ends40, an internally threaded hollow or tubular pin68is inserted up through the internal wall62. Concentric with the threaded pin68, the rotatable adjustment member34is maintained between the opposing legs40by the insertion of the threaded pin68through the throughbore42of each opposing leg.

The threaded pin68is preferably pressure fit with the rotatable adjustment member34. Preferably constructed of mild carbon steel, the threaded pin68is fixed relative to the rotatable adjustment member34, to rotate with the rotatable adjustment member. While in the preferred embodiment the threaded pin68is a separate piece from the rotatable adjustment member24, a one-piece rotatable adjustment member34with a threaded interior is contemplated. The threaded pin68preferably extends through each throughbore66of the opposing ends40, however other configurations that permit the rotation of the pin and the adjustment member34are contemplated.

Inside the threaded pin68, a threaded interior surface70is configured to receive the adjustment end28of the workpiece contact element26. When the rotatable adjustment member34is rotated, and thus the threaded pin68is rotated with the adjustment member, the threaded surface70acts on the adjustment end of the workpiece contact element26. Depending on the direction of threads, rotation of the adjustment member34in one direction causes the workpiece contact element26to displace upwards, while rotation of the adjustment member34in the opposite direction causes the workpiece contact element to displace downwards.

On the locking member38, preferably at the opposing leg40adjacent the top surface48of the rotatable adjustment member34, is at least one locating structure72. Preferably holes punched into the opposing leg40having generally the same dimensions as the locking detent50, the locating structure72is configured to positively receive the locking detent.

When the locking detents50are disposed in the locating structure68, the rotatable adjustment member34is in a locked position, prevented from movement.FIG. 6shows another embodiment of a locking member138having a locating structure172where the locating structure and a throughbore142are joined as a single hole through the leg40. Further,FIGS. 1 and 2show the locking member38having a locating structure72with a counterbore shape instead of a throughbore shape, however any shape which receives and locks the locking detent50is contemplated.

To move the rotatable adjustment member34to an adjustment position, the axially directed spring bias must be overcome by axially displacing the adjustment member away from the opposing leg40. As the rotatable adjustment member34is displaced away from the opposing leg40, the detents50disengage from the locating structure72. When the detents50are disengaged, the adjustment member34is freely rotatable and, as a result of the rotation, the workpiece contact element26displaces up or down in the threaded pin68.

In the locked position, the workpiece contact element26cannot move axially relative to the rotatable adjustment member34, 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 element26. It will be seen that the length of the threaded pin68and the adjustment end28of the workpiece contact element26allows the workpiece contact element to be adjusted axially relative to the rotatable adjustment member34to 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 member34may be manually overridden. Depending on the compression strength of the compression spring60, the user is able to manually override the locking member38by rotating the adjustment member24out of engagement with the locating structure68without first displacing the member away from the opposing leg40. In this configuration, the user is able to rotate the adjustment member24against the bias of the compression spring60until the detent50engaged in the locating structure68. This provides small incremental rotations, or “fine-adjustment,” of the depth of drive assembly10.