Field of the Invention

This invention generally relates to provide a floating fastener within the profile of an entity of a system to fasten another entity by coupling a screw with the said floating fastener, where nut fastener is used for fastening it with a screw.

Background of the Invention

Telecommunication circuit networks essentially consist of electronic devices arranged in a system. This system provides for a front panel consisting of a face plate, Printed circuit board (PCB), card cage and a latch mechanism on either side of the face plate to fasten the front panel with the chassis. The face plate area through the openings is the access point to the services offered by the PCB. The front panel with the PCB is guided by a card cage to attach the PCB with the back plane of the system. To firmly secure the front panel with the card guide attached to the chassis, a screw nut mechanism is provided on its either sides. The major consideration was fixing the screw with the nut in effective alignment with the axis of the screw and nut. This offset caused an assembly issue when the card is assembled to the chassis. Further repeated Jack-in and Jack-out of the front panel from the card cage and re-fixing the screw with the nut in spite of this offset damages the card guide as well as the face plate and renders it unfit for further use. Moreover, the pitch between the two nuts of the respective card guides on either side fails to maintain any tolerance so as to adjust with the screw and nut axis because in manufacturing it is difficult to maintain the pitch within 0.2 mm tolerance as lot of assemblies are involved. Another solution would be to use a standard floating nut. The limitation in the standard floating nut is that the nuts require a minimum card guide width of 17.6 mm. Therefore to provide a floating nut on card guides having a width less than 17.6 mm so as to maintain a tolerance of at least 1mm is required to minimize/ eliminate the JIJO (Jack-in-and jack- out) issues caused due to manufacturing.

Summary of the Invention

An aspect of the present invention it to address at least the above mentioned problems or disadvantages and to provide the advantages as below:

Accordingly an aspect of the present invention is to provide a floating fastener within the profile of the Card Guide. The floating fastener is provided with one or more obstructions, externally on at least one entity and integrally with the fastener. In one such embodiment the obstruction is provided integrally to the fastener by riveting the fastener to a piece of sheet metal which would be later assembled within the profile of the card guide. This sheet of metal housing the fastener has protrusions in plurality of shapes and in one embodiment of the invention the shape includes a rectangle, projecting like wings at its either ends. This protrusion is mounted on small rectangular slots provided on either side of the card guide profile as an obstruction on the other entity. The embodiments of the invention provide for appropriate slots matching the shape of the protrusion on the profile of the card guide. The floating movement of the fastener with the other entity is caused by engendering a relative motion between the floating fastener and the other entity such that the relative motion is limited on its horizontal, angular and planar movement. The floating fastener is arrested in a manner preventing any absolute rotational movement of the nut along its axis. Another aspect of the invention is to provide the floating fastener to perform in a manner of angular self-alignment with the screw thus eliminating the need to have an exact fit for both the screw and the axis of the floating fastener. The floating fastener with obstructions engaged within the slot provide for necessary anti-torque thus limiting their rotational movement (anti- torque) in a manner facilitating the coupling of the fastener with the screw.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

Brief description of the drawings

The features, advantages and other aspects of the embodiments of the present invention will be obvious to any person skilled in the art to appreciate the invention when read with the following description taken in conjunction with the accompanying drawings.

FIG 1 shows an isometric view of the floating fastener in accordance with the principles of the present invention.

FIG 2 shows an isometric rear view of the card guide in accordance with the embodiments of the present invention.

FIG 3 shows an isometric rear view of the floating fastener mounted on the respective slot on the card guide in accordance with the principles of the present invention.

FIG 4 shows the assembling sequence of the floating fastener with the card guide in accordance with the embodiments of the present invention.

FIG 5 shows the front view of the card guide engaged with the floating fastener in accordance with the embodiments of the present invention.

The figures are not drawn to scale and are illustrated for simplicity and clarity to help understand the various embodiments of the present invention. Throughout the drawings it should be noted that like reference numbers are used to depict the same or similar elements, features and structures.

Detail description of the Invention

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

Figs. 1 to 5 discussed below and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way that would limit the scope of the disclosure.
Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged systems. The terms used to describe various embodiments are exemplary. It should be understood that these are provided to merely aid the understanding of the description, and that their use and definitions in no way limit the scope of the invention.

Any term specifically reciting some of the present invention's characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including tolerances, measurement error, measurement accuracy limitations and other factors known to those of skilled in the art, may occur in amounts that do not preclude the effect the present invention was intended to provide.

Figure 1 depicts the floating fastener 15 in accordance with the embodiments of the present invention. In an embodiment of the invention a metal sheet 10 is customised to form a structure as shown in figure 1 with its body 10b having rectangular protrusions 10c on its both horizontal ends. The top vertical end surface 10e of the metal sheet 10 is flat which is followed by two adjacent inclined surfaces 10d on its either sides. Similar symmetrical shape encompasses the bottom surface (as shown partially in figure 1). The ends of the inclined surface 10d is bent perpendicularly towards the protrusion 10c such that the protrusion with its adjacent sides 10h resemble a rectangular flap having as its sides 10i along its length and 10j along its breadth. Through the metal sheet structure 10, a cylindrical threaded standoff 10a is riveted through the body of the metal sheet 10b such that the maximum area 10b of the metal sheet is enclosed by the cylindrical threaded standoff 10c. The forward projection of the cylindrical standoff 10a and its diameter are of specified dimensions so as to suit its varied applications. The front portion of the standoff comprises of a threaded hole having an outer circumference 10k and an inner circumference 10L. The inclined surface 10f connects the outer circumference 10k with the inner circumference 10L of the threaded standoff. The cylindrical threaded standoff 10a with the metal sheet 10 comprise to form a floating fastener 15 with its axis along 10g.

Figure 2 depicts a portion of the card guide frame 20 in accordance with the embodiments of the present invention. The card guide 20 is a C- shaped rectangular metal frame with its side 20b along its breadth having openings 20f at regular intervals. The side 20a bent backwards perpendicular to the side 20b is projected to a determined length. The top layer of the projected length is provided with slots 20d at regular intervals exactly coinciding with the openings 20f on the side 20b. The side 20g which is bent backwards perpendicular to the side 20b and parallel to the side 20a is an elongated metal frame which guides Circuit boards, PCB's though the grooves 20e to attach it with the chassis and to the back plane of the system. The side 20g is provided with slots 20i of similar dimension as that on 20a at regular intervals exactly coinciding with the openings 20f on 20b.

Figure 3 depicts a portion of the card guide frame 20 with the floating fastener 15 mounted on the C-profile of the card guide in accordance with the embodiments of the present invention. The protrusion 10c on the left side of the floating fastener is engaged with the slot 20i on the side 20g of the card guide and the protrusion 10c on the right side of the floating fastener is placed on the slot 20d on the side 20a of the card guide. The engagements of the protrusions with the slots are made easy as the width of the slots 20d and 20i on all its sides are greater than the width of the protrusion 10c on all its sides. The engagement of the protrusions with the slots ensures that the outer circumference 10k of the cylindrical portion 10a of the floating fastener matches the outer circumference of the circular opening 20f on the side 20b of the card guide such that the entire forward projection of the cylindrical portion 10a is inside the card guide frame facing the opening 20f on the side 20b of the card guide frame and its riveted junction 10m facing opposite to the opening 20f.

Figure 4 shows the assembling sequence of the floating fastener with the card guide frame 20 in accordance with the embodiments of the present invention. The protrusion 10c when mounted on the slot 20d on the card guide frame 20a is covered on three of its sides leaving one side open. A card guide plate 30 is attached to the open end of the protrusion. The card guide plate is a rectangular metal sheet with holes provided on its opposite ends along its breadth. The card guide plate 30 is mounted to the card guide frame such that its length 30a on its attaching side, covers the open ended surface of the protrusion 10c mounted on the slot 20d of the card guide frame 20a through screw nut fastening mechanism 40 enabled through the holes provided on the card guide plate 30 and the flaps 20h. The arrangement arrests the floating fastener 15.

Figure 5 shows the isometric front view of the floating fastener mounted on the C-profile of the card guide embodying the principles of the invention. The outer circumference 10k of the cylindrical portion 10a of the floating fastener coincides with the opening 20f on the side 20b of the card guide. As the outer circumference 10k of the floating fastener is merged with the opening 20f on the side 20b of the card guide, the inclined surface 10f (as shown in figure 1) ending with the inner circumference 10L of the floating fastener is visible apparently. The slot 20i on the side 20g of the card guide holds the right side protrusion 10c of the floating fastener with its extreme sides 10j visible externally. The C-profile of the card guide encompassing the sides 20a, 20b, 20c and 20g can house as many floating fasteners as required by the system. The illustrated card guide frame shows three such floating fasteners.

The vertical height of the slots 20d and 20i on sides 20a and 20g respectively on the C-profile of the card guide is bigger in size to that of the rectangular protrusion 10c of the floating fastener. The horizontal width of the slots 20d on side 20a and 20i on side 20g on the C-profile of the card guide is lesser than that of the length 10i of the protrusion 10c of the floating fastener. This arrangement provides for horizontal and vertical gaps for the protrusion 10c of the floating fastener on all its sides such that the floating fastener has a limited; floating; horizontal; angular and planar movement within the slot 20d and 20i on the C-profile of the card guide. The vertical gaps thus provided between the slots 20d, 20i and the protrusion 10c of the floating fastener enables the floating fastener to have a limited rotational movement along its axis 10g.
The horizontal gap due to the relative size difference between the horizontal slot width and the width of the protrusion 10c on all its other sides enables the floating fastener to have a limited horizontal and planar movement. The desired limited movement of the floating fastener along its vertical, horizontal and angular plane can be accomplished by allowing a pre-determined gap between the slot and the floating fastener so that the edges of the surfaces 10h,10i of the protrusion 10c encounters the inner surface of the slots 20d and 20i when it rotates at an angle or tends to make any to and fro motion and further rotation or to and fro movement is prevented due to the resistance offered by the inner slot surface to the sides of the protrusion 10c.

These pre-determined horizontal and vertical gaps thus provided to the floating fastener 15 on all its sides, engendered by relative size difference between the slots 20d, 20i and the protrusion 10c facilitates self-aligning feature. As shown in figure 5 the outer circumference 10k of the threaded standoff which coincides with the circumference of the opening 20f on side 20b of the card guide is inclined to fall at an angle to end with the inner circumference 10L of the floating fastener. The surface 10f inclined at an angle connecting the inner and outer circumferences of the floating fastener hole is at a pre-determined length. When a screw is projected towards the floating fastener for fastening, the posterior end of the screw touches at any point either on the inclined surface 10f or the threaded portion 10n of the floating fastener. The downward force exerted by the posterior end of the screw on the inclined surface 10f makes the floating fastener 15 to slide along the horizontal and vertical direction depending upon the point of impact of the posterior end of the screw. Similarly, when the posterior end of the screw touches the threaded portion 10n of the floating fastener, the relative gap between the slot width and the protrusion width enables the floating fastener 15 to have a floating movement along the horizontal and vertical direction. The floating movement of the floating fastener 15 is limited to the extent of the pre-determined gap allowed between the slots 20d, 20i and the protrusion 10c. The exertion of downward force of the posterior end of the screw will continue till it finds the axis 10g of the floating fastener. The floating fastener 15 by performing a sliding motion aided by the downward force of the posterior end of the screw aligns itself with the screw axis for coupling. The pre-determined gap between the slot and the protrusion can be of any dimension depending upon its application. The pre-determined gap in the preferred embodiment is at least 1 mm between the slot and the floating fastener on all of its sides so as to provide a floating fastener with a tolerance of 1mm thus enabling the floating fastener to have a limited horizontal, vertical and planar movement.

An aspect of the present invention is to remove the disadvantage of the existing prior art by providing at least a tolerance level of one mm between the floating fastener's axis and screw axis on a card guide whose width 20b is at least a minimum of 12 mm; where the prior art failed to maintain any tolerance for fastening the screw with the nut.

Further, in addition to the above illustrated floating fastener which is one among the embodiments of the present invention, it is possible to have floating fasteners of varying shapes and structures having additional components. The inventor envisages few among such floating fasteners in the shape of octagonal, hexagonal, pentagonal, triangular etc., In such sizes and shapes, the slot 20d as shown in figure 2 can be designed to provide the necessary width, matching the dimensions of the floating fastener so as to provide the floating fastener with limited vertical, horizontal and planar movement along with self-aligning feature by allowing pre-determined horizontal and vertical gaps such that necessary anti-torque is provided by limiting the rotation of the floating fastener well within its gaps between the slot and the protrusion 10c.

The foregoing merely illustrates the principles of the invention. The above illustrated floating fastener embodying the principles of the invention can have floating feature by holding the floating fastener stationary and causing a floating movement with the other entity that is fastened with this floating fastener. For example, the floating feature can be used in applications where the part fastened of to the floating fastener is required to have a controlled movement like a rocking action or any movement of the assembled part to accommodate 2nd layer/stage of assembly. This will help in aligning the assembly to latch on or fix onto other assembly. Thus floating movement embodied in the above invention is caused by engendering a relative motion between the floating fastener and the other entity.

A method of the above self-aligning floating fastener pursuant to the principles of the invention can be made from any desired material. Indeed, it can be made of steel, mild steel, die-cast materials, plastic, fibre, moulded material depending upon its applications.

Advantages:

1. The existing prior art did not provide for any tolerance for coinciding of screw axis with the nut axis enabling to fasten the screw with the nut on the card guide having a width less than 13mm. One embodiment of the present invention provided a tolerance level of at least 1 mm each on either of two card guides thereby allowing a smooth attachment of the face plate with the card cage. Further this reduced the stress upon the fastening mechanism on repeated jack-in and jack-out of the Printed Circuit Board.

2. Another solution to address the above issue was to have a standard floating nut. But the standard floating nuts require a minimum card guide width of 17.6 mm.

One embodiment of the present invention provided a floating fastener that would fit into C- profile of the card guide of the size 12.0 mm within the confined space thereby dispensing with the requirement of standard floating nut.

3. The embodiments of the above invention can be applied to any card guides with varying sizes where space constraints are involved.

4. The embodiments of the above invention can be also used in any floating nut mechanisms where space constraints are involved.

5. The embodiments of the above invention involved no new components.

6. The embodiments of the above invention made it possible to provide a floating fastener in the card guide with limited modification of the form fit or function of the card guide.

It will thus be appreciated that those skilled in the art will be able to device numerous alternative arrangements that, while now shown or described herein, embody the principles of the invention and thus are within its spirit and scope.

We claim:

1. The method for a floating fastener by

Providing one or more obstructions, externally on at least one entity and integrally with the fastener; and

Limiting the movement of the fastener so obstructed, by engendering relative motion between the fastener and the said entity such that the relative motion is limited in horizontal, angular and planar movement.

2. The method of claim 1 wherein integrally provided obstruction includes a sheet integral with the fastener, sheet fixed to the fastener with any self-locking mechanism, sheet riveted with the fastener or attached to the fastener by a threaded mechanism

3. The method of claim 2 wherein obstruction has surface area of at least one amongst any plurality of shapes including a rectangle, square, triangle, octagonal, hexagonal, circular, semi-circular, conical, pentagonal etc.,

4. The method of claim 1 wherein entity is provided with an external obstruction including a slot having surface area of at least one amongst any plurality of shapes including a rectangle, square, triangle, octagonal, hexagonal, circular, semi-circular, conical, pentagonal etc., such that the floating fastener, has a limited; horizontal, angular and planar movement relative to the external obstruction.

5. The method of claim 1 wherein the floating fastener enables coinciding of its axis with the screw axis during its coupling.

6. The method of claim 1 wherein limiting the movement prevents any 360 degree rotational movement of the floating fastener along its axis.

7. The method of claim 4 wherein slot includes creating an interface by cutting, slitting, drilling, plunging, stamping, bending or removal of material etc.,

8. The method of claim 1 wherein the fastener that is floated includes a threaded standoff, off the shelf nut, caged nut, captive floating nut, recess nut, any internally threaded entity, floating fastener etc.

9. The method of claim 1 wherein entity includes any two faces with the defined distance between them which includes a Card guide, chassis, Fan Tray Unit, hollow frames, solid frames, angle beam, etc.

10. The method of claim 1 wherein the floating fastener is made of any solid material including metals, die cast material, plastic, fibre, molded materials etc.

11. The floating fastener comprising of:

One or more obstructions, externally on at least one entity and integrally with the fastener, so as to engender relative motion between the fastener and the said entity such that the relative motion is limited in horizontal, angular and planar movement.

12. The floating fastener substantially described with reference to the accompanying drawings.