Patent Description:
The prior art is documented with examples of fasteners, such as which are configured in an attempt to prevent loosening when employed in dynamic environments. A first and most basic example of this is the conventional threaded bolt fastener with attachable and interiorly threaded nut. A spring washer can either be integrated into the nut or separately provided.

Other examples include the locking threaded fastener of<CIT>, which teaches a locking threaded fastener of the wedge-action type with threaded and threadless nut members with wedge elements therebetween for wedging the nut members apart when the threaded nut member is turned in the loosening direction. In a two-piece nut, the threadless nut member has a flat inner surface for engaging the workpiece and the wedge elements have engaging surfaces with a coefficient of friction therebetween which is less than that between the flat inner surface and the workpiece surface. In a three-piece nut, a third nut member, in the form of a washer, is provided with a flat inner surface for engaging the workpiece. The wedge elements have engaging surfaces with a coefficient of friction less than that between the third nut member and the threadless nut member which, in turn, is less than that between the third nut member in the workpiece.

<CIT>, teaches a vibration resistant fastener having a pin and a collar. The pin is threaded or peripherally grooved. At a central location, the major diameter of the thread or groove is reduced to a diameter which is still larger than its minor diameter. A collar is threaded or swaged on to the pin and collar material is pressed into an open region that was formed by the reduction of the major diameter, to form a thread lock.

<CIT> describes a bolt with a nut portion for tightening a bolt. The nut and the bolt are threaded so as to always rotate in opposite directions. An elastic body is sandwiched between the nut and the bolt so as to transmit the rotational motion.

<CIT> describes a structure for reducing loosening torque of a bolt by screwing a first auxiliary bolt until it is engaged with a locking stepped part. A bolt is screwed to a fitting body. A second auxiliary bolt is screwed so as to be abutted on the first auxiliary bolt.

<CIT> describes a locking structure for an object, constituted so that the locking of the object can be made stable by the use of an uncoupling prevention bolt.

<CIT> describes a nut having opposite screw threads.

<CIT> describes means for locking a nut on a bolt, comprising an inwardly tapered axial hole in the threaded end of the bolt, two diametrical slits at right angles to each other in the threaded end of the bolt which slits extend only partway along the threaded zone of the bolt, and a tapered pin adapted to be driven into the hole to expand the slit portion of the threaded zone of the bolt.

<CIT> describes a screw for holding including the female bolt having a flange-like holding part, in which a lock bolt insertion hole is passed through, that is formed in its one end, and an inner screw formed in its inner periphery, the male bolt having a flange-like holding part formed in its one end, an outer screw screwed in the inner screw of the female bolt, that is formed in an outer periphery of a rod-like part, and an inner screw screwing oppositely relative to the outer screw formed in the outer periphery of the rod-like part, that is formed in the inner periphery, and a lock bolt having an outer screw screwed in the inner screw formed in the rod-like part of the male bolt.

<CIT> describes a cylindrical body formed at a point of a first screw member, and screws are formed each on a peripheral face and on an inner circumference of the cylindrical body. A first screw member is inserted from the one side of a through hole formed in two pieces of plate materials, while a second screw member is inserted from the other side. Then, a third screw member is inserted into the cylindrical body of the first screw member from a through hole of the second screw member, and a screw of the third screw member is engaged in screws of the screw members, respectively.

According to a first aspect, there is provided a three-piece locking fastener according to the appended claims.

The present invention discloses a three piece locking fastener according to claim <NUM> including an interiorly threaded intermediate component open at opposite ends. A first screw having a first exterior thread pattern rotationally inter-engages with the interior threads of the intermediate component when installed through a first selected one of the opposite ends, the first screw having a hollow shaft exhibiting a further plurality of interior threads opposite a direction of the first thread pattern. A second screw has a second exterior thread pattern opposite the first pattern and, upon being installed within the other selected one of the opposite ends, rotationally inter-engages the interior threads of the first screw, so that loosening of either of the first and second screws being prevented by their counter-threaded orientation.

Additional features include each of the intermediate component and a selected one of the first and second screws having an enlarged head with a number of interconnected sides having a polygonal shape. The second screw further includes a curved and enlarged diameter head.

Other features include a tool bit engageable recess profile incorporated into the enlarged head. The intermediate component further includes an end proximate undercut recess for receiving the enlarged head of the second fastener. A recessed ledge is configured within the undercut recess of the intermediate component for seating an underside of the enlarged head of the second fastener in an installed position. A polygonal inner perimeter is configured in the undercut recess for communicating an extending stem of the second fastener within the intermediate component and in engagement with the hollow threaded interior of the previously installed first fastener.

Yet additional features include the intermediate component and the first and second fasteners each further including a rigid material not limited to a steel or heavy duty nylon construction. The first and second layers have aligning apertures through which a stem portion of the intermediate component extends, with the enlarged polygonal shaped heads established by the intermediate component and the selected one of the first and second screws compressing against opposite edge surfaces of the layers adjoining the apertures.

Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which:.

With reference to the following illustrations, the present invention discloses a three piece locking fastener for use such as in dynamic environments in which vibrations and other effects are in play. This can include without limitation such operating environments as skate blade fasteners for compressively attaching a first blade layer to a second layer, such as further including a support plate or the like formed with the bottom of the skate. Other applications include the three piece fastener being integrated into a wheel to hub attachment interface, such as for a vehicle.

As will be further detailed in reference to each of the alternate variants, the fastener assembly includes, at a minimum, an intermediate component which is interiorly threaded and open at opposite ends for receiving and first and second threaded screws. The first screw is exteriorly threaded for engaging with the threads of the intermediate component. The first screw includes a hollow shaft which, upon being installed within a first end of the intermediate component, subsequently receives in a counter-rotatatively threaded fashion a second threaded screw, with loosening of the opposing end screws being prevented via their counter-threaded orientation.

Referring initially to <FIG>, generally depicted at <NUM> is an assembled and partially transparent view of a three piece fastener according to a first variant of the present invention. As further shown in the exploded view of <FIG>, the three piece fastener includes intermediate component <NUM> and first (bottom) hollow screw <NUM> and second (top) solid screw <NUM>. Consistent with all of the variants, the intermediate component <NUM> and first <NUM> and second <NUM> fasteners can be constructed of any rigid material not limited to steel, carbon steel or any durable composite (e.g. nylon or polymer) material. As further understood, the screws <NUM> and <NUM> are also commonly termed as "threaded bolts" however can include any other suitable configuration for inter-engaging with the intermediate component <NUM> in the manner described herein.

<FIG> is a partially exploded view of <FIG> and illustrating the lower or first hollowed screw <NUM> engaged within the lower open and interiorly threaded end of the intermediate component <NUM> prior to engagement of the upper or second solid screw <NUM>. <FIG> is an axial cutaway view depicting the assembly of <FIG> and further showing first <NUM> and second <NUM> layers, each having aligning apertures depicted by inner perimeter surfaces <NUM> and <NUM>, respectively, and through which a stem portion (again at <NUM>) of the intermediate component extends. <FIG> further provides is an exploded axial cutaway view corresponding to <FIG> of the three piece fastener.

As previously described, the layers <NUM> and <NUM> are generally represented and can include any configuration or application not limited in one potential application to such as an attachment fastener for a skate blade to a flange, bracket or other support surface. In a further application, the layers <NUM> can correspond to an inner rim or wheel supporting a tire in attachment to a wheel hub. In each instance, the present invention serves to provide a durable fastener arrangement which resists loosening in response to vibrations and the like, such as which can be typical of dynamic operating environments.

The intermediate component includes an enlarged polygonal shaped head, such as which is depicted as a hex head configuration, see at <NUM>, which is shown proximate its upper open end. At least one of the selected screws <NUM>/<NUM> (or bolt threads) likewise include an enlarged hex head which is depicted in <FIG> by hex head <NUM> associated with the lower or first bolt <NUM>. Without limitation, the hex head can be substituted by any other circular or other type of fastening tool, such including but not limited to a multi-sided polygonal shape head having any of a triangular, square, pentagonal or other shape exhibiting a number of interconnected sides, it also being envisioned that the polygonal shaped enlarged heads can be reconfigured in other shapes consistent with the use of any tightening or loosening tool.

As also shown, the upper or second screw <NUM> includes a curved and enlarged diameter head <NUM>. A tool bit engageable recess (see square profile <NUM>) is formed in the enlarged head <NUM> to facilitate engagement by a tool bit (not shown) for securing the second (top) screw <NUM> following pre-threaded engagement of the exterior threads (at <NUM>) of the lower screw <NUM> within the interior threads (at <NUM>) of the intermediate component <NUM>.

As further shown, the first screw <NUM> includes a hollow shaft (see generally at <NUM> in <FIG>) exhibiting a further plurality of interior threads (further at <NUM>) opposite a direction of the first thread pattern <NUM>. In comparison, the second screw <NUM> exhibits a second exterior thread pattern <NUM> opposite said first pattern and upon being installed within the other selected one of the opposite ends (depicted as the upper end of the intermediate component <NUM> in <FIG>), results in rotationally inter-engaging of the thread pattern <NUM> with the matching interior thread pattern <NUM> of the first screw <NUM>, with loosening of either of the first <NUM> and second <NUM> screws being prevented by their counter-threaded orientation.

Additional features include the intermediate component <NUM> exhibiting an end proximate undercut recess, see annular inner rim surface <NUM> communicated with undercut ledge <NUM> in <FIG>, this for receiving and seating the enlarged head <NUM> of the second fastener <NUM> in the manner best further shown in <FIG>. A polygonal inner perimeter (see at <NUM>) configured in the undercut recess for communicating the solid extending stem (at <NUM> in <FIG>) of the second fastener within the intermediate component <NUM> and into engagement with the hollow threaded interior <NUM> of the previously installed first fastener <NUM>. The fasteners provided can again include, without limitation, any cross sectional shape not limited to circular or other configuration.

<FIG> is an assembled and partially transparent view of the three piece fastener as substantially shown in <FIG>, and further depicted at <NUM>' with the direction of the first and second screw threads being reversed as referenced by threads <NUM>' of the first fastener, at <NUM>' as further shown in <FIG>, arranged in a reversed directional pattern from those depicted at <NUM>' for second fastener <NUM>', as also shown in <FIG> is an exploded view depicting the three piece fastener of <FIG>, similar to that previously shown in <FIG> and again with the intermediate component <NUM>', first (bottom) hollow screw <NUM>' and second (top solid screw) <NUM>' with the reversed thread patterns <NUM>' and <NUM>'. An interior threaded pattern <NUM>' of the intermediate component <NUM>' (corresponding to that previously shown at <NUM> in <FIG>) is likewise opposite that of the exterior threads <NUM>'. Additionally, and for purposes of the present description, the reference to screw thread direction can also include the terms first/second, left/right or first and second opposing interchangeably and without limitation.

<FIG> correspond to <FIG> in the presentation of a three piece fastener according to a second variant of the present disclosure. For the purpose of clarity of description, additional figure descriptions for each of second variant of <FIG> (and related sub-variant <FIG>), as well as the third variant of <FIG> (and related sub-variant of <FIG>) will be limited to pointing out differences from that previously illustrated and described in the first embodiment. Similar features will remain as previously described or illustrated.

<FIG> is an assembled and partially transparent view of the three piece fastener according to a second variant of the present disclosure. <FIG> is an exploded view depicting the three piece fastener of <FIG> and, in differentiation from that shown in <FIG>, exhibiting an alternately configured intermediate component <NUM> with a non-recessed upper end surface <NUM>, this depicted in comparison to that shown in <FIG>, in combination with the first (bottom) hollow screw <NUM> and second (top) solid screw <NUM> as previously described and exhibiting the reversed thread directions.

<FIG> is a partially exploded view of <FIG> and illustrating the lower or first hollowed screw engaged within the lower open and interiorly threaded end of the intermediate component prior to engagement of the upper or second solid screw. <FIG> is an axial cutaway view of the depicting the assembly of <FIG> and in which the domed or arcuate profile <NUM> of the upper second screw <NUM> projects above the upper surface ledge <NUM> of the intermediate component <NUM> (and as opposed to being recess seated within the recess profile depicted at the upper end of the intermediate component <NUM> of <FIG> with the underside of the enlarged screw head of the second screw supported upon the undercut ledge <NUM> in <FIG>).

<FIG> is an exploded axial cutaway view corresponding to <FIG>, with <FIG> depicting is an assembled and partially transparent view of a three-piece fastener as substantially shown in <FIG> with the direction of the first and second screw threads being reversed. A square perimeter opening <NUM>' is referenced in the intermediate component <NUM> which corresponds to that shown at <NUM> in <FIG> and <FIG>, however is relocated more proximate the upper surface <NUM> of the intermediate component <NUM>. As with the first embodiment, the dimensions of the reduced dimension square profile enable inserting passage there-through of the threaded stem or shaft <NUM> of the upper screw <NUM> (see also again <FIG>). <FIG> is an exploded view depicting the three piece fastener of <FIG>, again with the intermediate component <NUM> and first (bottom) hollow screw and second (top solid screw) and reverse thread patterns (see also <FIG>) exhibited on the top and bottom screws and in the same manner previously described.

<FIG> is an illustration similar to previous <FIG> and <FIG> of an assembled and partially transparent view of a three-piece fastener according to a third variant of the present disclosure. <FIG> is an exploded view depicting the three-piece fastener of <FIG> with the intermediate component <NUM> and first (bottom) hollow screw <NUM> as depicted in <FIG>, the second (top) solid screw being alternately configured from that shown at <NUM> in <FIG>, and as further shown at <NUM> in <FIG>. In particular, the domed head <NUM> of the second screw <NUM> is reconfigured in this variant as a hex head <NUM> with a flat upper surface within which is configured the tool bit engaging square recess pattern <NUM>' reconfigured within the hex head <NUM>.

<FIG> is a partially exploded view of <FIG> and illustrating the lower or first hollowed screw <NUM> engaged within the lower open and interiorly threaded end of the intermediate component <NUM> prior to engagement of the upper or second solid hex head screw <NUM>. <FIG> is an axial cutaway view of the depicting the assembly of <FIG>, with <FIG> providing an exploded axial cutaway view corresponding to <FIG>.

<FIG> is an assembled and partially transparent view of a three piece fastener as substantially shown in <FIG> with the direction of the first and second screw threads being reversed, this further depicted in the exploded view of <FIG> with reversed thread patterns as previously shown in corresponding <FIG> (first variant) and <FIG> (second variant).

Referring now to <FIG>, an assembled and partially transparent view is generally shown at <NUM> of a three-piece fastener according to a further embodiment of the present invention. As additionally shown in the exploding and axial cutaway views in succeeding <FIG>, the three-piece fastener includes intermediate component <NUM> and first (bottom) hollow screw <NUM> and second (top) solid screw <NUM>.

As with the preceding variant, the intermediate component <NUM> and first <NUM> and second <NUM> fasteners can be constructed of any rigid material not limited to steel, carbon steel or any durable composite (e.g. nylon or polymer) material. As further understood, the screws <NUM> and <NUM> are also commonly termed as "threaded bolts" however can include any other suitable configuration for inter-engaging with the intermediate component <NUM> in the manner described herein.

<FIG> provides an axial cutaway view depicting the assembly of <FIG> and further showing the first <NUM> and second <NUM> layers (see also <FIG>) being secured together, each having aligning apertures again depicted by inner perimeter surfaces <NUM> and <NUM>, respectively, and through which the stem portion (again at <NUM>) of the intermediate component extends. <FIG> further provides is an exploded axial cutaway view corresponding to <FIG> of the three-piece fastener <NUM>.

As previously described, the layers <NUM> and <NUM> are generally represented and can include any configuration or application not limited in one potential application to such as an attachment fastener for a skate blade to a flange, bracket or other support surface. As also previously described, and in a further application, the layers <NUM> and <NUM> can correspond to an inner rim or wheel supporting a tire in attachment to a wheel hub such that the present invention serves to provide a durable fastener arrangement which resists loosening in response to vibrations and the like, such as which can be typical of dynamic operating environments.

The intermediate component <NUM> includes an enlarged polygonal shaped head, such as which is depicted as a hex head configuration at <NUM>, which is shown proximate its upper open end. At least one of the selected screws <NUM>/<NUM> (also again termed bolt threads) likewise include an enlarged hex head which is depicted in <FIG> by hex head <NUM> associated with the lower or first bolt <NUM>. As further again shown in <FIG>, the opposing inner ledge surfaces created by the enlarged hex heads <NUM> and <NUM> provide the sandwiching force to the proximate aperture surface perimeter locations of the layers <NUM>/<NUM> in the environmental illustration shown. Without limitation, the hex head can again be substituted by any other multi-sided polygonal shape head, not limited to any of a triangular, square, pentagonal or other shape exhibiting a number of interconnected sides, and it is also again envisioned that the polygonal shaped enlarged heads can be reconfigured in other shapes consistent with the use of any tightening or loosening tool.

The upper or second screw <NUM> includes a curved and enlarged diameter head <NUM>. A tool bit engageable recess (see as including a star profile <NUM> also known as a Torx style screw by non-limiting example) is formed in the enlarged head <NUM> to facilitate engagement by a tool bit (not shown) for securing the second (top) screw <NUM> following pre-threaded engagement of the exterior threads (at <NUM>) of the lower screw <NUM> within the interior threads (best shown at <NUM> in <FIG>) of the intermediate component <NUM>.

As further shown, the first screw <NUM> includes a hollow shaft (see generally at <NUM> in <FIG>) exhibiting a further plurality of interior threads (further at <NUM>) opposite a direction of the first thread pattern <NUM>. In comparison, the second screw <NUM> exhibits a second exterior thread pattern <NUM> which is opposite the first pattern and, upon being installed within the other selected one of the opposite ends (depicted as the upper end of the intermediate component <NUM>), results in rotationally inter-engaging of the thread pattern <NUM> with the matching interior thread pattern <NUM> of the first screw <NUM>, with loosening of either of the first <NUM> and second <NUM> screws being prevented by virtue of their counter-threaded orientation.

Additional features include the intermediate component <NUM> exhibiting an upper end proximate undercut recess, see annular inner rim surface <NUM> communicated with undercut ledge <NUM>, this for receiving and seating the enlarged head <NUM> of the second fastener <NUM> in the shown in <FIG> and <FIG>. A circular inner perimeter (see at <NUM>) is configured in the undercut recess for communicating the solid extending stem (at <NUM>) of the second fastener <NUM> within the open interior of the intermediate component <NUM> and into engagement with the hollow threaded interior <NUM> of the previously installed first fastener <NUM> according to the previously described counter-threaded and loosening preventative manner.

Claim 1:
A three-piece locking fastener (<NUM>), comprising:
an intermediate component (<NUM>) having a one piece body with an exterior surface and an enlarged polygonal shaped head (<NUM>), a first hollowed interior extending between opposite ends, said intermediate component (<NUM>) including a plurality of interior threads (<NUM>) arrayed in a first direction and extending from a first of said opposite ends, a recess (<NUM>) defined within said enlarged polygonal shaped head (<NUM>) and extending inwardly from the other of said opposite ends and terminating in an undercut ledge (<NUM>), a polygonal inner perimeter (<NUM>) configured in said recess (<NUM>) and communicating said first hollowed interior with said undercut ledge (<NUM>);
a first fastener (<NUM>) having a further one piece body with a first enlarged head (<NUM>) and a first stem with a second hollowed interior, a first exterior thread pattern (<NUM>) configured on said first stem extending in the first direction for rotationally inter-engaging with said interior threads (<NUM>) of said intermediate component (<NUM>) when installed through said first selected one of said opposite ends, said second hollowed interior of said first fastener (<NUM>) exhibiting a further plurality of interior threads (<NUM>) extending in a second direction that is opposite to the first direction; and
a second fastener (<NUM>) having a second enlarged head (<NUM>) and a second stem, upon which is configured a second exterior thread pattern (<NUM>) extending in the second direction and, upon being installed through said enlarged polygonal shaped head(<NUM>) and within the other selected one of said opposite ends of said intermediate component (<NUM>), said polygonal inner perimeter communicating said second stem within said intermediate component (<NUM>) and in engagement with said hollow threaded interior of said previously installed first fastener (<NUM>), with said second enlarged head (<NUM>) being received within said recess (<NUM>) and against said undercut ledge (<NUM>), said second fastener (<NUM>) rotationally inter-engaging said interior threads (<NUM>) of said first fastener (<NUM>) in the second direction, with loosening of either of said first and second fasteners (<NUM>, <NUM>) being prevented.