Spring loaded gear bolt assembly and method

Repeated inserting, tightening, loosening, and removing of external threads to internal threads can increase the likelihood of cross threading and thread damage. A spring loaded gear bolt assembly, which promotes alignment of mating threads before applying torque, is described. A spring is disposed on the back end of a bolt shaft to promote alignment of lead mating threads before twisting to engage external to internal threads. A gear chain translates a single hand rotation to thread two bolts into respective affixed internal threaded holes, simultaneously. A spring loaded gear bolt assembly and method described herein promote increased thread life and ease of use ease for test plate securing. Efficient single handed manipulation of multiple bolts simultaneously can be achieved using a test plate assembly, which included spring loaded gear bolt assemblies, as described herein. Applications of a spring loaded gear bolt include infrared adapter test plate assemblies.

BACKGROUND OF THE INVENTION

The present invention relates generally to preventing thread damage across pairs of external bolt threads and internal mating threads. Thread damage is an ongoing challenge in bolt fastening applications. Numerous factors can contribute to thread damage. Repeated fastening and unfastening may add to the opportunity for damaging threads. Cross threading can lead to fastener failure. Different bolt applications and configurations can present additional challenges for potential cross threading as compared with a conventional straight on bolt and nut application.

It would be desirable to provide a method and system which promoted alignment of external bolt threads and internal mating threads to preserve external and internal threads.

SUMMARY OF THE INVENTION

The present invention addresses the issue of thread preservation in securing or fastening applications across external bolt threads and internal affixed. The present invention provides a spring loaded gear bolt assembly which protects lead threads and affords aligning the male and female threads before engaging mating threads. A test plate assembly comprising spring loaded gear bolt assemblies, in accordance with the present invention, permits simultaneous alignment of multiple sets of bolt threads and affixed internal threads with a single-handed operation. Certain aspects of the present invention are briefly described below but are not exhaustive. Further, any one embodiment in accordance with the present invention may include any of the certain aspects described below.

One aspect of the present invention is that it may be incorporated into a test plate assembly.

Another aspect of the present invention is that affords alignment of lead threads before application of torque upon the threads.

Another aspect of the present invention is that it promotes on axis contact of lead threads despite an off axis application of insertion force; and further, another aspect of the present invention is that it facilitates axial thread alignment despite the application of torque at an off axis point and the application of torque upon a bolt shaft at less than the bolt circumference.

Another aspect of the present invention is its ready incorporation into a single handed test plate mounting assembly.

Another aspect of the present invention is that the aligning force can be varied as needed for the application requirements.

Another aspect of the present invention is that the displacement afforded by the aligning force can be varied.

Another aspect of the present invention is that the aligning force and displacement can be varied independently.

Another aspect of the present invention is the binding-free mounting of a test plate assembly to an affixed assembly, which is afforded in part by spring loading, in accordance with an embodiment of the present invention.

Yet another aspect of the present invention is the relative hardness of parts in the gear bolt assembly, to preserve the gear bolt assembly as well as the lead threads on the bolt and in the mounting plate.

An aspect of the present invention is a decreased potential for cross threading; embodiments enable seating of the bolt evenly before turning to translate male threads of bolt shaft into female threads of affixed receptor, which decreases the chances of cross threading.

Another aspect of the present invention is the protection of threads during insertion and securing of multiple bolts simultaneously with a single hand.

Those skilled in the art will further appreciate the above-noted features and advantages of the invention together with other important aspects thereof upon reading the detailed description that follows in conjunction with the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The invention, as defined by the claims, may be better understood by reference to the following detailed description. The description is meant to be read with reference to the figures contained herein. This detailed description relates to examples of the claimed subject matter for illustrative purposes, and is in no way meant to limit the scope of the invention. The specific aspects and embodiments discussed herein are merely illustrative of ways to make and use the invention, and do not limit the scope of the invention. Element Reference numbers in the figures are consistent across figures, when possible. Parts are not necessarily identical across figures and are not necessarily consistent across embodiments.

FIGS. 1A-1Dshow a top view, side view, front isometric view, and a back view, respectively, of an embodiment of a test plate assembly utilizing a gear bolt assembly in accordance with an embodiment of the present invention.FIG. 1Ashows a top view of a face plate of a test plate assembly, in accordance with an embodiment of the present invention. Centered in the face plate110is grip120. A user will rotate grip120clockwise121to secure the test plate assembly100, shown inFIG. 1Bto the mounted receiving plate. And conversely, rotating grip120counter-clockwise122will loosen the test plate assembly100for removal. InFIG. 1A, dust cap130is shown secured to the adapter, not shown, while a dust cap holder132is within tether133distance for ready storage during testing.

FIG. 1Bshows a side view of a closed test plate assembly100in accordance with an embodiment of the present invention. Adapter125provides electrical connections for the desired voltage tests. Spring housings140,145extend outward from the face plate110on which they are mounted. As shown inFIG. 1A, spring housings140,145are at the lower left and upper right corners of the face plate110. For example, the depth of the adapter125, grip120and spring housings140,145may not be shown to scale. And these elements, for example, can vary in diameter and depth as desired in accordance with an exemplary embodiment of the present invention. Similarly, the height of the dust cap holder can vary and may be threaded.

FIG. 1Ashows the spring housing secured to the face plate10via a pair of screws18. Additional screws18secure the face plate10to the back plate90, where back plate90is shown in side viewFIG. 1B.

In diagonal corners opposite the spring housings45,40are aligning pin holes12,17, which extend through both the face plate10and the back plate90, as shown inFIGS. 1A and 1C. The aligning pins, not shown, are affixed to the receiving plate. The receiving plate, not shown, houses the pins or other connection types to be tested.

FIG. 1Cshows a front isometric view of spring housings40,45adapter25, and grip20, and their relative positions on face plate10.FIG. 1Calso provides a perspective view of aligning pin holes17,12on a first diagonal and the spring housings40,45on a second diagonal. Bolt shafts80,85extend out the back side91of back plate90. Turning toFIG. 1D, contact pin pads38extend through openings98in the back plate90. Bolt shafts85,80extend through the back plate as well.

FIG. 2shows an exploded perspective view of the test plate assembly100. The inside92of the back plate90faces the back of circuit board60. The gear chain350rests atop circuit board60, which is disposed between the face plate10and the back plate90.FIGS. 3A-3Bshow the gear chain and its relation to the gear housing70,76in greater detail. Bolt shafts80,85extend through back plate90before entering respective gear housings70,76. Inserted in gear housings70,76are respective springs80S,85S. The gear housing and bolt shaft are shown in greater detail inFIG. 4. Gear housings70,76extend from the gear chain350through face plate10. Spring housings40,45cover the portion of the respective gear housing, which extends out of the face plate210, and in which respective springs80S,85S are housed. The user grip20is mounted on the face plate10and is used by a user to secure and remove the test plate assembly,100from the receiving plate, not shown. Also shown extending from the front of the face plate is adapter25, which is capped by dust cap30.

In accordance with an exemplary embodiment of the present invention in ensemble of o-rings is used throughout the test plate assembly to withstand salt water and other corrosive environments. O-ring48frames circuit board60and is disposed between face plate10and back plate90.

FIG. 3Ashows a perspective view of the gear chain350, which is housed between face plate10and the back plate90, and just above the circuit board60. Circuit board60is disposed inside a large recess97of the inside92of back plate90. Gear housings70,76are shown extending out of inner sides92back plate90, whilst bolt shafts80,85extend out the opposite side91of the back plate90. Stem355engages, is connected to, center gear354, which connects the grip (not shown) to the gear chain350. In accordance with an exemplary embodiment, an over torque clutch is disposed between the grip and gear housing, to prevent over torque on the threads of the bolt shaft.

FIG. 3Bis an exploded view of the gear chain350and circuit board60in the back plate90. End gears358,353engage the respective gears75,78on the gear housings70,76. Gears in the gear chain rest between spacers373, separating the gear from the circuit board surface60. The gear chain350rests in the recess97of the back plate90. The gear75,78of respective gear housing70,76are also set into a recess97of back plate90, and rest on a respective spacer, not shown. The number of gears in the gear chain350and relative ratios may vary across embodiments, as desired or as space and load requirements dictate.

FIG. 4shows a detailed view of a gear bolt assembly400, in accordance with an exemplary embodiment of the present invention. Bolt shaft480has a thread-less insertion lead460with an outer diameter that is just less than the minor diameter of the internal threads in the receiving plate. The diameter of the thread-less insertion section460is also less than the minor diameter of the threaded bolt section456. The thread-less insert section backs up to the threaded portion456of the bolt shaft450. In accordance with the exemplary embodiment ofFIG. 4, the total threaded length is 0.20 inches. In alternate embodiments the thread length can be longer or shorter as desired or as needed to withstand the resultant load. According to one exemplary embodiment, the bolt shaft is under tensile load when bolted into the receiving plate. In alternate embodiments, the parameters, such as, pitch, major axis, minor axis, thread height, and thread length of the bolt shaft can vary as desired or as needed to meet application requirements. The material of the bolt shaft or threads can also vary.

A thread-less section455follows the threads456. The thread-less section455has an outer diameter less than the minor diameter of the threads456. Next to the thread-less section455is a displacement limiting shoulder section454. Referring toFIG. 2, back plate290has through-holes in diagonal corners through which bolt shafts280,285pass, where an exemplary bolt shaft is shown as450inFIG. 4. The upper end, or head end,452of bolt shaft450inserts into gear housing470. Bolt shaft450inserts into gear housing470, which has a spring end471and a gear and475. Gear housing470has an inner diameter which affords ready insertion of the bolt shaft450.

Bolt shaft450has a through hole452which is aligned with through slot473in the gear housing. Dowel472passes through the top slot473and hole452and out the bottom slot, not shown, of the gear housing. The distance of hole452to the head451of the bolt shaft is less than the distance of the slot to the471end of the gear housing470. After insertion of the bolt shaft into the gear housing and after insertion of dowel472through the slot473and whole452, there is empty headspace in gear housing470. Spring480inserts, at least partially, into gear housing470. The outer diameter of spring480fits easily into the diameter of the gear housing and rests against the head of the bolt451.

FIG. 5shows a cross section of a gear bolt assembly as disposed in a test plate assembly, in accordance with an embodiment of the present invention, along line X-X ofFIG. 1A. When the gear bolt assembly is mounted in a test plate assembly500, spring housing540fits over the head end of gear housing570and any spring portion580which extends past the housing570. Dowel572has an outer diameter which affords ready displacement along the gear housing axis riding in the slot573. In accordance with one exemplary embodiment the slot573permits 1/10 of an inch displacement of the bolt shaft relative to the gear housing. A method of securing a test plate assembly500to receiving plate and a method of assembling a spring-loaded gear bolt assembly are described in reference toFIG. 5.

In accordance with the present invention, an exemplary embodiment of a spring loaded gear bolt assembly comprises: a spring580580s; a spring housing540; a gear housing570with slot573and gear575; a bolt shaft550with a through hole553, a shoulder554, a threaded section556, and an insert section560; and a dowel572. Bolt shaft550inserts through opening in the back plate590and into gear housing570. Gear575of gear housing570rests in a recess597of back plate590while the head-end of gear housing570extends through face plate510. Disposed in the head end of the gear housing570and resting on the head end of bolt shaft550is spring580580s. Atop spring580and surrounding the portion of the gear housing, which extends past the face plate510, is spring housing540.

In accordance with an exemplary embodiment, insertion section560has radiused edges561and an outer diameter562, which is less than the minor diameter of internal receiving threads affixed in a receiving plate. An exemplary receiving plate is shown in FIG,7. A receiving plate, to which a test plate assembly in accordance with an embodiment of the present invention may be secured, may be an infrared adapter receiving plate. The infrared adapter receiving plate may be affixed on an aircraft, manned or unmanned, for which flare deployment is desired. Further, while embodiments of the present invention are described, for example inFIGS. 1-5, in relation to an infrared adapter, or infrared decoy flare receiving plate, a test plate assembly and spring loaded gear bolt assembly in accordance with the present invention can be modified and employed to other types of receiving plates. For example, a chaff, or electronic counter measure, receiving plate can be affixed to any aircraft and a test plate assembly housing a spring loaded gear bolt assembly, in accordance with an exemplary embodiment of the present invention, may be secured thereto for testing purposes. The placement of the spring loaded gear bolt assembly within the test plate assembly can be varied to align with affixed internal receiving threads, and the dimensions, e.g. frontal plane dimensions, of the test plate assembly can be varied as needed or desired to mount to a specific receiving plate.

FIG. 7does not show electrical contact pins of the receiving plate, which may align with some or all of contact pads38, shown inFIG. 1D. The number and placement of contact pads38in a test plate assembly, in accordance with the present invention, may also vary as desired or needed to correspond with electrical contacts in a receiving plate.FIG. 7shows affixed internal threads785a,780ainto which the bolts80,85(FIG. 1) will thread. In opposite corners, corresponding to the exemplary embodiment ofFIGS. 1A-1D, pins712aand717acorrespond to through holes17and12(FIGS. 1A and 1D).

After placing the gear housing570into recess597and after placing additional intermediate parts, such as the gear chain565and the circuit board, not shown, the face plate510and back plate590can be secured together. The bolt shaft550can be inserted through opening596and secured in the gear housing by aligning the hole553of bolt shaft550with the slot573of the gear housing570and inserting the dowel572, as shown inFIG. 5. In accordance with the embodiment ofFIG. 5, gear575rests on a washer578at its gear end575and up against spring housing540on its other end, fixing, at least in part, the position of the gear housing in the Z direction505. With a spring580splaced into the head end of the gear housing570, the spring housing540can enclose the spring580sand the exposed end of the gear housing570and can be secured to face plate510.

Once the test plate assembly500is assembled it can be secured to the receiving plate. In accordance with one exemplary embodiment, the receiving plate is a flare loading plate, which is affixed to, for example, an aircraft. In accordance with the present invention, single handed mounting, securing, and removing are enabled. Referring toFIG. 1B, grip120can be used to align the holes112and117to the receiving plate pins712a,717a(FIG. 7). Additionally, a notch113may be present and aligned on a receiving bar or channel lock. The inserting end560of bolt shaft,FIG. 5, will align with corresponding internal threaded holes in the receiving plate. Centering the single handed grip130,FIG. 1A, on the face plate110ergonomically favors balance across the test plate assembly100in both frontal plane directions x and y. According to one exemplary embodiment, the spring constant of spring580(FIG. 5) is one pound. When the insertion end of the bolt shaft560(FIG. 5) acquires an impacting force of one pound or greater, the bolt shaft550will displace along its axis as afforded by slot573and space595. This axial displacement will enable the lead external threads556to align with corresponding lead internal threads on the receiving plate. By compressing the spring and evenly seating the mating threads before rotating the grip, the likelihood of cross threading is reduced. Even with repeated securing and removal of the test plate assembly500to a receiving plate, threads556are preserved and protected. Further, this protection is provided to two spatially separated bolts simultaneously during the simultaneous securing of said two bolts from a single site of torque application, which is a user grip. Single handed securing and removing of a test plate assembly into a receiving plate is afforded by the present invention, while enabling alignment of threads before engaging and loading external and internal threads of two respective bolts.

In yet other embodiments, additional gear bolt assemblies can be employed. Possible configurations include a gear chain running across the opposite diagonal, referring toFIG. 3A. In another embodiment, the circuit board60(FIG. 2) can be displaced from the gear chain. For example a gear chain plate could be disposed on the face plate side of circuit board.

Referring toFIG. 1D, contact pads38, which are distributed across the face of the back plate, will depress corresponding pin contacts of the receiving plate when the test plate assembly is secured to the receiving plate. In accordance with one exemplary embodiment, thirty pounds of pressure are applied via the contact pads to depress the army of contact pins on the receiving plate. The desired electrical connection is provided from the receiving plate pins to adapter25(FIG. 1B) for testing. In alternate embodiments, the form of electrical connections between the receiving plate and the test plate assembly can vary as desired or as needed in accordance with the configuration of the receiving plate.

As described above, the present invention affords simultaneous alignment and subsequent securing of two bolts using a single handed operation. Additional gear bolt assemblies can be employed at additional places along the gear chain. The gear chain can be expanded or shortened in length. Similarly a gear chain running in the opposite direction, or another direction can be employed. Displacing the circuit board from the gear chain would afford multiple center gear, gear chain, to gear housing configurations. A single gear, e.g. a large gear at center gear354position, may replace the gear chain350to provide connection to gear end of gear housings78,75(FIGS. 3A and 3B), placed about the circumference of the single gear. Additional gear housings can be positioned along the circumference of the single gear as needed for load accommodation or receiving plate configuration.

In accordance with an exemplary embodiment, for example as shown inFIGS. 1A-1D, aligning pins on the receiving plate717a,712aare provided to assist in aligning the connection of the test plate assembly with the receiving plate. The translation afforded by space95and slot73(FIG. 5) may lessen binding of the test plate assembly on the pins during insertion. The binding-free, or reduced binding, mounting of a test plate assembly to an affixed receiving plate assembly is afforded in part by spring loading, in accordance with an embodiment of the present invention. The binding reduction can be adjusted by respective spring constants and by the number of springs employed, where a spring80S is comprised in a gear bolt assembly, shown for example inFIGS. 5 and 4.

Another aspect of the present invention is that the aligning force can be varied as needed for the application requirements. The aligning force can be adjusted by the choice of spring used in the gear bolt assembly. Another aspect of the present invention is that the displacement afforded by the aligning force can be varied. The displacement obtained in response to the applied aligning force can be adjusted by, for example, by the length of slot73and the depth of recess95. In turn, in accordance with embodiments of the present invention, the aligning force and displacement can be varied independently.

FIG. 6Ashows a block diagram of a method of securing a test plate assembly to an affixed receiving plate. Through holes in a test plate assembly are aligned with pins in a receiving plate610. The test plate assembly is pushed towards the receiving plate620. The lead end of at least one bolt is inserted into a corresponding internally threaded hole in the receiving plate630. Using a user grip, the user pushes on a face plate of the test plate assembly, which compresses a spring within the spring loaded gear bolt assembly and mates the corresponding lead threads640. Once the spring loaded gear bolt assembly compresses, the user may turn the user grip which will apply a torque on the bolt shaft, threading the external bolt threads into the internal threads650.

FIG. 6Bshows a block diagram of a method of simultaneously aligning at least two sets of lead external bolt shaft threads and affixed internal mating threads mounted in a receiving plate. A user first obtains spring loaded gear bolt assemblies615and a test plate assembly which housed at least two spring loaded gear bolt assemblies625. The user positions the test plate assembly juxtaposition the receiving plate with internal mating threads635. Contact is made between lead external threads and corresponding internal threads in the receiving plate645. Pressing on the front plate of the test plate assembly, compresses a spring in respective spring loaded gear bolt assemblies, displacing the at least two bolt shafts normal to the receiving plate aligning mating threads axially655. Then, turning a user grip on the front plate of the test plate assembly will apply a torque on the bolt shaft, threading the external threads into the mated internal threads of the receiving plate.

The present invention enables inserting and threading of two bolt shafts simultaneously with one hand, while aligning respective lead threads before torque application, which decreases the potential for cross threading, wherein the bolt threads are machine threads not designed to cut. While specific alternatives to steps or elements of the invention have been described herein, additional alternatives not specifically disclosed but known in the art are intended to fall within the scope of the invention. Thus, it is understood that other applications of the present invention will be apparent to those skilled in the art upon reading the described embodiment and after consideration of the appended claims and drawings.