WO2020209982A1

WO2020209982A1 - Fiber optic hardware assembly having a panel locking feature

Info

Publication number: WO2020209982A1
Application number: PCT/US2020/022884
Authority: WO
Inventors: Christophe Desard
Original assignee: Corning Research & Development Corporation
Priority date: 2019-04-08
Filing date: 2020-03-16
Publication date: 2020-10-15

Abstract

A fiber optic hardware assembly is provided including a frame, a panel having a first end and a second end. The first end of the panel is pivotally coupled to the frame such that the panel is movable between an open position and a closed position. The fiber optic hardware assembly also includes a panel lock coupled to the second end of the panel. The panel lock incudes a first arm opposite a second arm, wherein the first arm and the second arm each include a locking feature configured to engage the frame to secure the panel in the closed position.

Description

FIBER OPTIC HARDWARE ASSEMBLY HAVING A PANEL LOCKING FEATURE

PRIORITY APPLICATION

[0001] This application claims the benefit of priority of U.S. Provisional Application No. 62/830,636, filed on April 8, 2019, the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD

[0002] This disclosure generally pertains to fiber optic hardware assemblies, and more particularly fiber optic hardware assemblies including a panel locking feature.

BACKGROUND

[0003] In fiber optic networks, fiber optic elements like fiber splices, splitters, fiber optic connectors, or excess length of fiber or fiber slack are often accommodated in drawers disposed in a cabinet, a rack, or a frame. From a fiber optic cable, individual fibers or groups of fibers are routed through the cabinet to the drawers, in which they are connected or spliced to other fibers, split, or stored and routed back inside the cabinet from the drawer to the same or a different fiber optic cable. Often, a plurality of such drawers is arranged in a rack of a fiber optic cabinet in a stacked manner to save space in the cabinet. Each individual drawer can be extended relative to the rack and/or other drawers. For example, each drawer may be pivoted about a pivot hinge defining a horizontal or vertical pivot axis into a position outside the stack of drawers, so that the drawer and the elements arranged in the drawer are accessible to an installer. It is advantageous to route fibers from the cabinet into a pivotable drawer close to the pivot axis of the drawer. This routing generally reduces pull stress on the fibers, when the drawer is pivoted from a pivot-in position ("storage position" or“closed position”) into a pivot-out position (“access position” or “open position”), and/or reduces fiber slack when pivoting back.

[0004] To maintain drawers in a closed position when not being serviced, a fastening device may be used. One such fastener may be a threaded screw configured to pass through an aperture in a front panel of the drawer and thread into a receiving aperture in a frame or housing.

However, screw fasteners may easily be subjected to overtightening that may cause subsequent opening of the front panel to be difficult or cause damage to the front panel, the fastener, and/or the frame. Further, screws may generate wear products, such as metal filings, during repeated use or be subject to fatigue including fracture and ductile failure.

[0005] Another common fastener may include quarter turn fasteners. Some example quarter turn fasteners have T-type fastening ends that are configured to pass through a slot aperture in the frame or housing and then be rotated 90 degrees, such that the T end is retained by the frame or housing. Other quarter turn fasteners may include fasteners that expand a rubber grommet when rotated, such that the expanded grommet is retained by the frame or housing. Although these fasteners are not as susceptible to over torqueing, they are subject to similar cyclic stresses and wear as the screw fasteners.

[0006] Still another type of fastener may include expanding plunger fasteners, sometime referred to as“Push-Pull” fasteners. When a head of the fastener is pushed, a plunger rod may cause a distal portion of the fastener to expand, as the plunger rod is pushed through a central aperture of the fastener. The expanded portion distal end of the fastener retains the panel in the closed position when the plunger is pushed in and retracts, releasing the panel, when pulled out. These fasteners may overcome the problem of over torqueing, but have significant cyclic stress on both the head of the plunger and the expanding portion of the distal end of the fastener.

SUMMARY

[0007] An embodiment of the disclosure is directed to a fiber optic hardware assembly including a panel lock. More particularly, the provided panel lock has a pair of opposing arms having a lock feature di sposed at the distal end of each and configured to engage the frame of the fiber optic hardware assembly. In an example embodiment, the locking features may be lock projections extending substantially perpendicular from the arms at a first end and corresponding apertures disposed in the frame. Additionally, in an example embodiment, the opposing arms include an actuator disposed at a second end opposite the first end. The actuators may include a portion of the first and second arm that curve in a direction opposite of the lock projection. In operation, a user pinches the actuators together causing the lock projections to expand away from one another, thereby releasing the frame.

[0008] To facilitate installation, including backwards compatibility, the panel lock includes a mounting plate. The opposing arms may be configured to pivot about the mounting plate between a locked position and an unlocked position. The mounting plate may also include one or more mounting clips configured to couple the panel lock to the panel. For example, the panel may include one or more apertures, including or in addition to apertures, configured to receive the opposing arms. The mounting clips may be configured to elastically deform to pass through the one or more apertures and return to their original shape once through, limiting or preventing removal of the panel lock from the panel. In some example embodiments, the mounting plate includes a guide feature configured to align the panel lock with the frame when moving from the open position to the closed position. For example, the mounting plate may include a guide feature corresponding to an aperture in the frame. Misalignment of the opposing arms with their respective apertures is corrected as the guide feature is received by the aperture in the frame, as the panel transitions from the open to the closed position.

[0009] The panel lock may be formed from a variety of materials including metal, plastic, or the like. In a preferred embodiment, the panel lock may be formed from injected molded plastic.

[0010] Additional features and advantages will be set forth in the detailed description which follows, and in part will be apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.

[0011] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.

[0012] The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings are illustrative of selected aspects of the present description, and together with the specification explain principles and operation of methods, products, and compositions embraced by the present description. Features shown in the drawing are illustrative of selected embodiments of the present description and are not necessarily depicted in proper scale.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the written description, it is believed that the specification will be better understood from the following written description when taken in conjunction with the accompanying drawings, wherein: [0014] FIG. 1 is a perspective view of a fiber optic hardware assembly including a panel lock according to an example embodiment;

[0015] FIGS. 2A and 2B are perspective views of a panel lock according to an example embodiment;

[0016] FIGS. 3A and 3B are perspective views of the panel lock of FIGS. 2A and 2B installed in a swivel drawer according to an example embodiment;

[0017] FIG. 4 is a perspective view of the panel lock of FIGS. 2A and 2B engaging a frame according to an example embodiment;

[0018] FIG. 5 is a cross-sectional perspective view similar to FIG. 4;

[0019] FIG. 6 is a perspective view similar to FIG. 4 including operational annotations according to an example embodiment;

[0020] FIG. 7 is a perspective view of the panel lock of FIGS. 2A and 2B securing a swivel drawer in a closed position; and

[0021] FIG. 8 is a perspective view of a panel lock of FIGS. 2A and 2B installed in a swivel drawer, with the swivel drawer being in an open position.

[0022] The embodiments set forth in the drawings are illustrative in nature and not intended to be limiting of the scope of the detailed description or claims. Whenever possible, the same reference numeral will be used throughout the drawings to refer to the same or like features. The drawings are not necessarily to scale for ease of illustration an explanation .

DETAILED DESCRIPTION

[0023] FIG. 1 depicts a perspective view of an example fiber optic hardware assembly 10 according to an example embodiment. The fiber optic hardware assembly 10 may include a frame 12 configured to support one or more fiber optic components including, but not limited to housings, cassettes, splitters, or the like. The frame 12 may be formed from steel, aluminum, or other suitable structural material. In some embodiments, the fiber optic hardware assembly 10 may include an enclosure 14 configured to protect the fiber optic equipment from a surrounding environment. The enclosure may be formed from steel, plastic, aluminum, or other suitable material. In a manner not entirely shown in FIG. 1, the enclosure 14 may include a base and an opposing top, first and second opposing side walls extending vertically from the base to the top, and a rear wall extending vertically from the base to the top and extending from the first side wall to the second side wall. The enclosure 14 may also include a forward opening disposed opposite the rear wall allowing access to the fiber optic equipment. An access door 16 may be disposed proximate to the forward opening and be configured to move between an open position and a closed position. The access door 16 encloses the forward opening in the closed position and allows access through the forward opening in the open position. In some example embodiments, the access door 16 and/or the periphery of the forward opening may include a seal material, such as rubber, polymers, or the like, to provide a barrier to the environment surrounding the fiber optic hardware assembly 10. In an example embodiment, a side wall and/or the rear wall may also include an opening and an access door 16, enabling access to further portions of the fiber optic hardware equipment assembly

10.

[0024] As discussed above, the fiber optic hardware assembly 10 may include one or more fiber optic components, which may be disposed in a drawer 18. The drawer 18 may be movable between an open position, e.g. an access position, enabling access to the fiber optic components, and a closed position, e.g. a storage position, limiting access to the fiber optic components. The drawer 18 may include a front panel 20 (“panel 20”) disposed at a forward end of the drawer 18. The panel 20 may be integral to the drawer 20, such that the panel 20 moves with the drawer 18 between the open position and the closed position. In an example embodiment, the drawer 18 may be a pull drawer configured to slide on rails in and out of the fiber optic hardware assembly 10. Additionally or alternatively, the drawer 18 may be a swing or otherwise pivotable drawer, as depicted in FIG. 1. The panel 20 of the swing drawer may include a first end 26 and a second end 28. The first end may be pivotably coupled to the frame 12, such as by a hinge 22. The panel 20 may be movable, e.g. pivotable, between the closed position and the open position. In still further embodiments, the panel 20 may be a blank configured to cover a space in the fiber optic hardware equipment assembly 10 that does not currently have a fiber optic component installed. In other words, the panel 20 in some embodiments may not necessarily be associated with a drawer yet still be movable between an open position and closed position.

[0025] The panel 20 may include a panel lock 24. The panel lock 24 may be coupled to either the first end 26 or the second end 28 of the panel 20 (coupling to the second end 28 is shown in FIG. 1). The panel lock 24 may be configured to engage the frame 12 to secure the panel 20 when the drawer 18 and/or panel 20 is in the closed position. [0026] The panel lock 24 discussed herein is depicted on a swing drawer for illustrative purposes. One of ordinary skill in the art would immediately appreciate that the panel lock 24 may be installed on a pull drawer, a blank panel, or the like.

[0027] FIGS. 2A and 2B depict perspective views of a panel lock 100 according to an example embodiment. The panel lock 100 may be similar to panel lock 24 discussed above in reference to FIG. 1. The panel lock 100 may include first and second opposing arms 101. Each of the opposing arms 101 may include a locking feature 102 disposed at a first end of each opposing arm 101. In an example embodiment, the locking feature 102 may comprise a lock projection extending substantially perpendicular from each opposing arm 101. The lock projections may be configured to engage a corresponding aperture 202 disposed in a frame 200, as depicted in FIGS. 4-6.

[0028] In an example embodiment, the panel lock 100 may include a mounting plate 104. The mounting plate 104 may be configured to couple the panel lock 100 to the panel 206, as depicted in FIGS. 3A and 3B. The mounting plate 104 may include one or more mounting clips 106 configured to couple the panel lock 100 to the panel 206. The mounting clips 106 may be configured to be compressed, e.g. elastically deform, to pass through one or more apertures 208 disposed in the panel 206. The one or more clips 106 may expand after passing through the apertures 208 thereby affixing the mounting plate 104 to the panel 204. In the example depicted in FIGS. 3 A and 3B, the panel lock 100 is mounted to the second end of a panel 206 disposed on a swing drawer, such as the swing drawer 18 depicted in FIG. 1. As discussed above, the swing drawer 18 is merely illustrative. The panel lock 100 may be mounted to blank panels, front panels on pull drawers, or the like. Further, a panel lock m ay be mounted on one or both ends of the panel 206, or in further locations. In some example embodiments, the panel lock 100 may be configured to be reverse compatible, such that the panel lock 100 may be installed in the existing fastener holes of previous model panels without need for additional fastener holes.

[0029] In some example embodiments, the mounting plate 104 may provide a fulcrum point for the opposing arms 101. The opposing arms 101 may be configured to pivot about the mounting plate 104 between a locked position, in which the locking feature 102 is engaged with the frame 200, and an unlocked position, in which the locking feature 102 is disengaged from the frame 200. In some example embodiments, a connection arm 107 may be disposed between the mounting plate 104 and the opposing arms 101 providing increased flexibility to the fulcrum point and reducing risk of brittle or ductile failure. In an example embodiment, one or more of the mounting clips 106 may be disposed on the connection arm 107. The panel lock 100 may be formed from plastic, metal, or other suitable material. In an example embodiment, the panel lock 100 may be formed from injection molded plastic enabling rigidity sufficient to resist opening of the panel when the panel lock 100 is in the locked position and enabling elastic deformation sufficient to allow the opposing arms 101 to pivot without causing plastic deformation. Operation of the opposing arms 101 and locking features 102 is discussed in further detail below in reference to FIG. 6.

[0030] In an example embodiment, the panel lock 100 may include a guide feature 108. The guide feature 108 may be configured to align the panel lock 100 with the frame 200 when the panel 206 is moving from the open position to the closed position. The guide feature 108 may include a projection configured to correspond with an aperture 202 in the frame 200, as depicted in FIG. 4. The guide feature 108 may extend from, and/or be integral to, the mounting plate 104. The guide feature 108 may include a beveled top edge and/or bottom edge, e.g. the width of the guide feature 108 increases from a distal end to a proximal end of the guide feature 108. Contact between the beveled top edge or bottom edge of the guide feature 108 with an edge of an aperture 202 in the frame, will cause the panel lock 100, and associated panel 206, to lower or raise, respectively, to align the opposing arms 101 with corresponding apertures 202 in the frame 200. Similarly, if the panel lock 100 and/or guide feature 108 orientation were rotated, the guide feature 108 may cause the panel lock 100 and associated panel 206 to move to one side or the other to align the opposing arms 101 with corresponding apertures 202 in the frame 200.

[0031] The panel lock 100 may also include one or more actuators 110. The actuators 1 10 may be disposed at the second end of the opposing arms 101. The actuators 110 may comprise an extension of the opposing arms 101 from the fulcrum point opposite the locking features 102. The actuators 110 may provide leverage to pivot the opposing arms 101 from the locked position to the unlocked position. In an example embodiment, the actuators 110 may comprise curved portions of the opposing arms 101. The curved portion of each of the opposing arms 101 may curve in a direction opposite the lock projection of the respective arm 101 (i.e., opposite the direction along which the lock projection extends). The curved portions may maximize leverage and/or provide an ergonomic contour for a user to operate the panel lock 100. [0032] FIG. 5 is a cross-sectional perspective view of the panel lock 100 engaging with a frame 200 according to an example embodiment. The cross-sectional view provides further detail of the features discussed above in reference to FIGS. 2-4.

[0033] Operation of the panel lock 100 according to an example embodiment is depicted in FIGS. 6-8. The panel 206 may start in the closed position with the panel lock 100 in the locked position engaged with the frame 200, as depicted in FIG. 7. An operator may squeeze the actuators 110 toward each other, as depicted by arrows D1 and D2 (FIG. 6). The opposing arms 101 may pivot about the fulcrum point defined by the mounting plate 104, causing the locking features 102 to deflect outward away from each other, as indicated by arrows D3 and D4. As the locking features 102 deflect outward, the locking features 102 disengage the frame 200. Once the locking features 102 have disengaged the frame 200, the panel lock 100 is in the unlocked position and the opposing arms 101 may be withdrawn from the apertures 202 in the frame 200, as the operator moves the panel 206 from the closed position to the open position, as depicted in FIG. 8. The operator may then release the actuators 110. The opposing arms 101 may return the locked position by rotating inward at the first end including the locking features 102 and away from each other at the second end including the actuators 1 10, e.g. in directions opposite the arrows D1-D4.

[0034] To lock the panel 206, the operator may squeeze the actuators 110 moving the locking features 102 to the unlocked position. The operator may then move the panel 206 from the open position to the closed position, in which the opposing arms 101 extend through the apertures 202 in the frame 200. Once the panel 206 is in the closed position, the operator may release the actuators 1 10 causing the locking features 102 to pivot toward each other engaging the frame 200.

[0035] In some example embodiments, the panel lock 100 may be configured to lock the panel 206 in the closed position when the panel 206 is transitioned from the open position to the closed position, without actuation of the panel lock 100. For example, the locking features 102 may include a beveled forward face. The beveled face may be configured, such that if the panel 206 is shut with the panel lock 100 in the locked position, the bevel face may contact the edge of an aperture 202 in the frame 200. The interaction between the beveled face and the edge of the aperture 202 may cause the locking features 102 to deflect away from each other in a manner similar to operation of the actuators 110 by the user, as discussed above. The locking features 102 may transition to the unlocked position as the beveled face passes through the aperture 202 and then return to the locked position. The beveled face enables the panel 206 to lock when pushed to the closed position without actuation of the panel lock 100.

[0036] As described above the panel lock provides a fastener that is not susceptible to over torqueing and is significantly less susceptible to cyclic stress. These advantages may limit or prevent damage to the frame, panel, enclosure, etc. as well as increase the effective life of the fastener. The panel lock also provides a tool-less method of locking and unlocking a panel that can be retrofit to previous panel designs.

[0037] In an example embodiment, a panel lock is provided including first arm opposite a second arm each including a locking feature disposed at a first end. The panel lock is configured to be operably coupled to an end of a front wall of a panel disposed in a fiber optic hardware assembly. The panel is pivotally coupled to a frame such that the panel is movable between an open position and a closed position. The locking features are configured to engage the frame of the fiber optic hardware assembly when the panel is in a closed position to prevent the panel from moving to the open position.

[0038] In an example embodiment, the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending substantially perpendicular from the first arm or the second arm and the lock projection of the first arm and the lock projection of the second arm are configured to engage a corresponding aperture in the frame.

[0039] In some example embodiments, the panel lock also includes a mounting plate and the first arm and the second arm are each configured to pivot relative to the mounting plate between a locked position and an unlocked position. In an example embodiment, the mounting plate includes one or more mounting clips configured to couple the panel lock to the second end of the panel. In some example embodiments, the mounting plate also include a guide feature configured to align the panel lock with the frame when moving the panel lock from the open position to the closed position.

[0040] In an example embodiment, the first arm and the second arm each include a first arm end at which the lock feature is disposed, a second arm end opposite the first arm end, and an actuator disposed at the second arm end. In some example embodiments, the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending in a direction substantially perpendicular from the first arm or the second arm and the actuator of the first arm and the actuator of the second arm each comprise a curved portion of the first arm or the second arm that curves in a direction opposite the direction along which the lock projection of the corresponding first arm or second arm extends. In some example embodiments, the panel lock is formed from molded plastic.

[0041] In further example embodiments, a panel for fiber optics equipment and a method including one or more of the features described above is provided.

[0042] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[0043] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the illustrated embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments that incorporate the spirit and substance of the illustrated embodiments may occur to persons skilled in the art, the description should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A fiber optic hardware assembly, comprising:

a frame;

a panel having a first end and a second end, wherein the first end of the panel is pivotally coupled to the frame such that the panel is movable between an open position and a closed position; a panel lock coupled to the second end of the panel, the panel lock comprising:

a first arm opposite a second arm, wherein the first arm and the second arm each include a locking feature configured to engage the frame to secure the panel in the closed position.

2. The fiber optic hardware assembly of claim 1, wherein the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending substantially perpendicular from the first arm or the second arm, and wherein the lock projection of the first arm and the lock projection of the second arm are configured to engage a corresponding aperture in the frame.

3. The fiber optic hardware assembly of either claim 1 or 2, wherein the panel lock further comprises a mounting plate, and wherein the first arm and the second arm are each configured to pivot relative to the mounting plate between a locked position and an unlocked position.

4. The fiber optic hardware assembly of claim 3, wherein the mounting plate comprises one or more mounting clips configured to couple the panel lock to the second end of the panel.

5. The fiber optic hardware assembly of either claim 3 or 4, wherein the mounting plate comprises a guide feature configured to align the panel lock with the frame when moving the panel from the open position to the closed position.

6. The fiber optic hardware assembly of any of claims 1-5, wherein the first arm and the second arm each include a first arm end at which the lock feature is disposed, a second arm end opposite the first arm end, and an actuator disposed at the second arm end.

7. The fiber optic hardware assembly of claim 5, wherein the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending in a direction substantially perpendicular from the first arm or the second arm, and wherein the actuator of the first arm and the actuator of the second arm each comprise a curved portion of the first arm or the second arm that curves in a direction opposite the direction along which the lock projection of the corresponding first arm or second arm extends.

8. The fiber optic hardware assembly of any of claims 1-7, wherein the panel lock is formed from molded plastic.

9. A panel assembly for fiber optic equipment comprising:

a panel having a first end and a second end, wherein the first end of the panel is configured to be pivotally coupled to a frame of a fiber optic hardware assembly, such that the panel is movable between an open position and a closed position when pivotally coupled to the frame; and a panel lock operably coupled to the second end of the panel, the panel lock comprising: a first arm opposite a second arm, wherein the first arm and the second arm each include a first arm end and a locking feature disposed at the first arm end, and wherein the l ocking feature of the first arm and the locking feature of the second arm are configured to engage the frame when the panel is in the closed position to prevent the panel from moving to the open positi on.

10. The panel of claim 9, wherein the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending substantially perpendicular from the first arm or the second arm, and wherein the lock projection of the first arm and the lock projection of the second arm are each configured to engage a corresponding aperture in the frame.

11. The panel of either claim 9 or 10, wherein the panel lock further comprises a mounting plate, and wherein the first arm and the second arm are each configured to pivot relative to the mounting plate between a locked position and an unlocked position.

12. The panel of claim 11, wherein the mounting plate comprises:

one or more mounting clips configured to couple the panel lock to the second end of the panel; and

a guide feature configured to align the panel lock with the frame when moving the panel from the open position to the closed position.

13. The panel of any of claims 9-12, wherein the first arm and the second arm each include a second arm end opposite the first arm end and an actuator disposed at the second arm end.

14. The panel of claim 13, wherein the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending in a direction substantially perpendicular from the first arm or the second arm, wherein the actuator of the first arm and the actuator of the second arm each comprise a curved portion of the first arm or the second arm that curves in a direction opposite the direction along which the lock projection of the corresponding first arm or second arm extends.

15. A method comprising:

providing a panel lock comprising a first arm opposite a second arm, wherein the first arm and the second arm each include a locking feature disposed at a first end

coupling the panel lock to an end of a panel disposed in a fiber optic hardware assembly, wherein the panel is coupled to a frame such that the panel is movable between an open position and a closed position, and wherein the locking features are configured to engage the frame of the fiber optic hardware assembly when the panel is in a closed position to prevent the panel from moving to the open position.

16. The method of claim 15, wherein the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending substantially perpendicular from the first arm or the second arm, and wherein the lock projection of the first arm and the lock projection of the second arm are each configured to engage a corresponding aperture in the frame.

17. The method of either claim 15 or 16, wherein the panel lock further comprises a mounting plate, and wherein the first arm and the second arm are each configured to pivot relative to the mounting plate between a locked position and an unlocked position.

18. The method of claim 17, wherein the mounting plate comprises:

19 The method of any of claims 15-18, wherein the first arm and the second arm each include a second arm end opposite the first arm end and an actuator disposed at the second arm end.

20. The method of claim 19, wherein the locking feature of the first arm and the locking feature of the second arm each comprise a lock projection extending in a direction substantially perpendicular from the first arm or the second arm, wherein the actuator of the first arm and the actuator of the second arm each comprise a curved portion of the first arm or the second arm that curves in a direction opposite the direction along which the lock projection of the corresponding first arm or second arm extends.