Methods and apparatus for an enhanced driving bit

Methods and apparatus for an enhanced driving bit according to various aspects of the present technology include a bit comprising a plurality of driving surfaces having a limited length and a shoulder portion positioned between the driving surfaces and a mid-body portion of the bit. The length of the driving surfaces is selected to allow complete insertion into a recessed socket area of a fastener such that the entire driving surface is positioned within the recessed socket area. The shoulder surface is configured to distribute localized stresses away from the driving surfaces to the mid-body portion more efficiently to reduce a potential for breakage of the driving surfaces during use.

BACKGROUND OF INVENTION

Presently fasteners are made with various recesses and matched driving tools, or bits, such as the Phillips® design, Torx®, straight walled hexagon, and other multi-fin geometries. Driving bits comprise driving walls and faces designed to fit within a recessed socket area of the fastener. However, to enable insertion of the driver into the recessed socket area, there must be some clearance between the driving tool and the recessed socket area of the fastener. As a result, the area of contact is typically less than full face-to-face contact between the driving tool and the recessed socket area of the fastener. In addition, the driving walls of the driving bit are longer than the recessed socket area of the fastener is deep such that a significant portion of the driving walls is not inserted into the recessed socket area. Consequently, when torque is applied by the driving bit to the fastener, the forces applied to the fastener head and driving walls are concentrated in localized stress regions. These localized stresses may lead to breakage of the bit. Efforts to increase the strength of the driving walls commonly focuses on the use of stronger materials or increasing the thickness of the driving walls. These efforts may provide some increased strength but the results are often limited due, at least in part, to size constraints of the related geometries.

SUMMARY OF THE INVENTION

Methods and apparatus for an enhanced driving bit according to various aspects of the present technology include a bit comprising a plurality of driving surfaces having a limited length and a shoulder portion positioned between the driving surfaces and a mid-body portion of the bit. The length of the driving surfaces is selected to allow complete insertion into a recessed socket area of a fastener such that the entire driving surface is positioned within the recessed socket area. The shoulder surface is configured to distribute localized stresses away from the driving surfaces to the mid-body portion more efficiently to reduce a potential for breakage of the driving surfaces during use.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present technology may be described in terms of functional block components and various processing steps. Such functional blocks may be realized by any number of components configured to perform the specified functions and achieve the various results. For example, the present technology may employ various types of materials, fastening devices, driver systems and the like, which may carry out a variety of functions. In addition, the present technology may be practiced in conjunction with any number of processes such as the manufacture of drivers for fasteners, mechanical attachment, and torque transmitting systems, and the system described is merely one exemplary application for the invention. Further, the present technology may employ any number of conventional techniques for metalworking, component manufacturing, tooling fabrication, and/or forming surfaces.

Methods and apparatus for an enhanced driving bit according to various aspects of the present technology may operate in conjunction with any suitable torque delivery system. Various representative implementations of the present technology may also be applied to any device capable of being inserted into and rotating a fastener.

Referring now toFIG. 1, in an exemplary embodiment of the present technology, an enhanced driving bit may comprise a bit102comprising a body having a shank portion106at a first end, a mid-body section108, and a driving portion112positioned at a second end. The bit102may comprise any suitable device or system for mating with the fastener104to facilitate a transfer of torque from the bit102to the fastener104. For example, the bit102may comprise a multi-lobular surface configured to be selectively inserted into and conform to a recessed socket area114of the fastener104and engage an inner surface of the recessed socket area114. The engagement between the bit102and the fastener104may create sufficient surface contact to couple the bit102and the fastener104together through a compressed or “stick fit” such that the fastener104does not fall off or otherwise automatically disengage from the bit102after the bit102has been inserted into the recessed socket area114of the fastener104.

The bit102may comprise any suitable material capable of withstanding torque forces between the fastener104and the bit102. For example, the bit102may comprise a metal or alloy that may be hardened or anodized. The material may also be capable of being subjected to one or more types of machining operations such as grinding, cutting, heading, hobbing, cold forming, or the like.

The shank portion106allows the bit102to be coupled to a device to allow the bit102to be rotated and apply a torque to the fastener104. The shank portion106may comprise any suitable size or shape and may be configured in any suitable fashion. For example, in one embodiment, the shank portion106may comprise a series of sidewall elements forming hexagonal shape to allow the bit102to be selectively inserted into a receiving mechanism such as a chuck of a mechanical screw gun, drill, robotic arm, or the like. In an alternative embodiment, the shank portion106may comprise a circular shape suitably configured to be coupled to a handle to form a manually operated device such as a screw driver.

The mid-body section108extends at least part way between the shank portion106and the driving portion112. The mid-body section108may be formed integrally with the shank portion106to create single unitary structure or may have a separate shape from the shank portion106. For example, the bit102may be formed from a single metal rod, wherein the mid-body section108retains the original dimensions of the metal rod and the shank portion106is subjected to a machining operation to form a surface that may be used to couple the bit102to a device such as a drill or other like device that is configured to rotate the bit102.

Referring now toFIG. 2, the driving portion112is configured to apply a torque force to the fastener104when the bit102is rotated. In one embodiment, the driving portion112may be adapted to provide a stick-fit when inserted into recessed socket area114such that the surface frictional forces between the driving portion112and the recessed socket area114of the fastener104are sufficient to couple the bit102and the fastener104together to allow single handed operation.

The driving portion112may comprise any suitable shape or size for engaging the recessed socket area114of the fastener104. For example, the driving portion112may comprise a shoulder surface208extending longitudinally away from the mid-body section108and a torque surface202extending outwardly from the shoulder surface208. The torque surface may be suitably configured to engage or otherwise substantially conform to a surface located within the recessed socket area114.

The torque surface202may extend between a base portion204and an end portion206. The torque surface202may be aligned substantially parallel to the shank portion106or the mid-body section108. Alternatively, the torque surface202may taper towards a longitudinal axis200of the bit102. A distance between the base portion204and the end portion206may comprise a length selected such that the entire torque surface202may be inserted into the recessed socket area114so that the shoulder surface208will abut the recessed socket area114and no portion of the torque surface202is positioned outside of the recessed socket area114when the bit102is used to torque the fastener104. Limiting the length of the distance between the base portion204and the end portion206ensures that the entire length of the driving surface is in contact with the recessed socket area114and is being used to transfer a torque to the fastener104. This substantially eliminates a situation where one portion of an individual torque surface202is applying a torque to the fastener104and a second portion of the individual torque surface202is not applying a torque because it is not in contact with the recessed socket area114of the fastener104. For example, the torque surface a prior art style driver bit has a length greater than the recessed socket area114of a standard screw head resulting in the torque surface the prior art style driver bit extending outward beyond the top of the screw head.

For example, in one embodiment, the distance between the base portion204and the end portion206may be less than two tenths of an inch when the recessed socket area114has a depth of about two tenths of an inch. In a second embodiment, the distance between the base portion204and the end portion206may be less than about five one hundredths of an inch when the recessed socket area114has a depth of between about five one hundredths of an inch and seven one hundredths of an inch.

In alternative embodiments, the distance between the base portion204and the end portion206may be determined according to a relationship between a length of the driving portion112and the shoulder surface208. Referring now toFIG. 8, in one embodiment, the distance between the base portion204and the end portion206may comprise a length L1and the shoulder surface208may comprise a length L2. L1may comprise a length at least as long as one-half of L2but not greater than twice L2. For example, in one embodiment, L1may comprise a length between about one and one and one-half times that of L2. Limiting the length of L1helps to ensure that the driving portion112may be fully inserted into the recessed socket area114of the fastener104.

Referring now toFIGS. 3 and 4, the torque surface202may further comprise a plurality of fins302that project outwardly from the longitudinal axis200. The plurality of fins may comprise any number and may be determined according to a particular type of fastener that the torque surface202is intended to engage. For example, the plurality of fins302may be oriented equidistantly around the longitudinal axis200and be suitably configured to engage standard Torx® and Phillips® style fasteners. Alternatively, and referring now toFIG. 5, the plurality of fins302may be spaced equidistantly around the longitudinal axis200and be configured with a customized geometry. In yet another embodiment and referring now toFIG. 6, the plurality of fins302may be oriented around the longitudinal axis200with a nonsymmetrical spacing between each individual fin from among the plurality of fins302. The number of fins302shown inFIGS. 3-6is representative illustrations only. In practice, the number of fins302making up the torque surface202may comprise any suitable number and may be determined according to any suitable criteria. For example, a customized bit102for use with a security fastener may comprise up to ten fins302and be arranged symmetrically or nonsymmetrically around the longitudinal axis200.

Each fin302may comprise a driving wall304, a removal wall306, and a first transition wall extending between the driving wall304and the removal wall306. The torque surface may also comprise a second transition wall extending between the driving wall304of a first fin and the removal wall306of a second fin. Each of these walls may be suitably configured to mate to a corresponding surface within the recessed socket area114of the fastener104. For example, the driving wall304may comprise a constant fin height from the base portion204to the end portion206that equals a height of a corresponding driving surface within the recessed socket area114. In addition, the driving wall304may be configured to be aligned with the axis200of the bit102such that there is substantially complete face-to-face contact between the driving wall304and the driving surface within the recessed socket area114during engagement. This allows the driving force to be spread across a larger area than is achievable through known fastener systems that only provide localized contact between the driving surface and a corresponding surface within the fastening device.

Similarly, the removal wall306may be configured to have the same dimensions as the removal surface212such that there is substantially complete face-to-face contact between the removal wall306and a corresponding removal surface within the recessed socket area114during engagement. For example, in one embodiment, the removal wall306may form a substantially mirror image of the driving wall304.

Alternatively, in a second embodiment, the removal wall306may form a non-vertical line relative to the axis200of the bit102as it extends from the base portion204to the end portion206in an equivalent manner to the removal surface. The non-vertical line may lie on an angle that causes the first transition wall to become progressively smaller as it descends toward the end portion206. Likewise, as the driving wall304, the removal wall306, the first transition wall, and a second transition wall progress to the end portion206of the torque surface202, each surface may taper inwardly towards the axis200such that the polygonal shape of the fins have a smaller area at the end portion206than at the base portion204. The end result is that the torque surface202tapers the same in every dimension as the recessed socket area114and is the same size at every corresponding position to the recessed socket area114. Accordingly, when the bit102is inserted into the recessed socket area114, the entire the torque surface202is in contact with every surface of the recessed socket area114both longitudinally and horizontally. The similar geometry allows the torque surface202to be wedged into the recessed socket area114to create a substantially 100% wedged fit between the bit102and the fastener104in all directions and with no portion of the torque surface202extending out of the recessed socket area114.

This wedged fit may further align the bit102and the fastener104during use by reducing tolerances between the torque surface202and the recessed socket area114. Reduced tolerances may result in a decreased likelihood that the bit102may wobble within the recessed socket area114when the driving force or removal force is being applied which reduces the chances of cam out and/or disengagement. The wedge fit during use may also decrease plastic deformation on the driving wall304and the removal wall306which results in decreased wear on the torque surface202and the recessed socket area114.

Referring now toFIG. 10, the driving portion112may further comprise a tapered nose section1002extending outwardly away from the torque surface202and towards the longitudinal axis200by an angle σ of between about sixty degrees and about seventy-five degrees relative to a sidewall of the mid-body section108. The tapered nose section1002may be configured to fit into a mating recess1004in the recessed socket area114. For example, in one embodiment, the angle σ may be equal to about seventy degrees to allow the tapered nose section1002to conform to a taper of the same amount present in a screw head.

The tapered nose section1002may help center the torque surface202during insertion or allow the torque surface202of a customized bit to be indexed more easily to a correct position and provide complete insertion of the driving portion112into the recessed socket area114. The tapered nose section1002may also allow for improved engagement between the torque surface202and the fastener104be reducing or eliminating a radius at an end of the torque surface202. For example, standard flat nosed driver bits often comprise a radius of at least 0.020 inches at the tip that prevents the driver bits from getting full engagement at insertion depth.

The tapered nose section1002may be formed in any suitable manner to allow for a tip of the driving portion112to be adapted to various types of recessed socket areas114. For example, referring now toFIG. 11, in one embodiment the tapered nose section1002may extend almost to a pointed tip1102that may only comprise a slightly blunted or flat surface that is suitably configured to reach all the way down to the bottom of the recessed socket area114. Referring now toFIG. 12, in an alternative embodiment, the tapered nose section1002may be formed to accommodate a security pin (not shown) positioned within the recessed socket area114. For example, the tapered nose section1002may comprise a shortened length that results in a larger and more blunt tip1202with respect to that shown inFIG. 10. The blunt tip1202allows for an opening1204to be positioned within the driving portion112that may receive the security pin.

In prior art driver bits, the transition between the torque surface202and the mid-body section108is abrupt commonly forms a substantially ninety degree angle. The abrupt transition creates a location of increased stress that increases a likelihood that one or more fins of the torque surface202will break during use since the torque forces are not efficiently transferred from the driving portion112to the mid-body section108of the bit102.

Referring again toFIG. 2, to reduce the potential for breakage of the torque surface202, the shoulder surface208is positioned between the mid-body section108and the base portion204of the driving portion112to help distribute torque forces away from the torque surface202by creating a more gradual transition between the mid-body section108and the driving portion112. The shoulder surface208may comprise any suitable shape or size for reducing localized stress regions on the driving portion112to reduce a potential for the fins to break during use. For example, the shoulder surface208may comprise a surface tapering towards the longitudinal axis200by an angle α of between about thirty degrees and about eighty degrees relative to a sidewall of the mid-body section108.

Referring now toFIG. 7, in an alternative embodiment, the shoulder surface208may comprise a curved surface702, or bullnose, that tapers towards the longitudinal axis200. The curved surface may be slightly convex and be configured to intersect each of the mid-body section108and the base portion204at an angle other than ninety degrees. Referring now toFIG. 8, in yet another embodiment, the shoulder surface208may comprise a curved concave surface802that tapers towards the longitudinal axis200and is configured to intersect each of the mid-body section108and the base portion204at an angle other than ninety degrees.

By shortening the length of the driving portion112to ensure full insertion into the recessed socket area114and incorporating the shoulder portion, overall strength of the driver bit102is increased and the likelihood of fin or torque surface202breakage is reduced. For example, in testing, a prior art Torx® style driver bit was inserted into a fastener head and torqued until the torque surface202broke. During testing, the prior art driver bit broke when subjected to approximately fifty-five to sixty inch pounds of torque. A driver bit102of the present technology was then subjected to the same testing and broke at approximately ninety-five to one hundred five inch pounds of torque. Similar increases in strength were found in other styles of driver bits evidencing the benefits of the reduce length of the driving portion112and the incorporation of the shoulder surface208between the driving portion112and the mid-body section108.

The shoulder surface208and the driving portion112may be formed by any suitable method such as by forming, forging, casting, cutting, grinding, milling, and the like. In one embodiment, the shoulder surface208and the driving portion112may be formed through a metal operation such as cold heading or hobbing. For example, referring now toFIG. 13, a wire blank may be fed into a heading machine and cut to a predetermined length (1301). The wire blank may then be positioned in front of a die (1302). The wire blank may then be forced into the die in a first blow forming an intermediate shape (1303). A second blow may be applied to the intermediate shape with a hammer that is suitably configured to form the torque surfaces202of the driving portion (1304). The bit102may then be ejected from the header machine (1305) and moved to a subsequent machining operation such as to form the shoulder surface208and the shank portion106(1306).

In an alternative embodiment, the shoulder surface208and the driving portion112may be formed through a series of computerized numerical controlled (“cnc”) machining steps. For example, the torque surface202may initially be milled on an end portion of a metal rod. The metal rod may then be positioned within a lathe to form the shoulder surface208and the tapered nose section1002.

In the foregoing specification, the invention has been described with reference to specific exemplary embodiments. Various modifications and changes may be made, however, without departing from the scope of the present invention as set forth in the claims. The specification and figures are illustrative, rather than restrictive, and modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents rather than by merely the examples described.

For example, the steps recited in any method or process claims may be executed in any order and are not limited to the specific order presented in the claims. Additionally, the components and/or elements recited in any apparatus claims may be assembled or otherwise operationally configured in a variety of permutations and are accordingly not limited to the specific configuration recited in the claims.