Latch improvement for overhead frame corners

Abstract

Improved latches for overhead corners which reduce the susceptibility of bundled frame components becoming unlatched and separated due to insufficient torque of latch knobs or to repeated shock. The improved latches retain the prior art notched latches along with their strength and simplicity, but are capable of absorbing shock by accommodating a rotational dynamic present in a latch-to-strike connection rather than attempting to prevent it. One of two styles of moveable, pressure-actuated latch keepers is joined to a notched latch of an overhead frame. One style of keeper provides a barrier into the latch's notch, while another style of keeper provides a barrier relative to the strike's features. The latch keepers provide a predetermined amount of resistance to a radial force applied to the latch. This force retains the strike into the latch's notch in a fully-seated orientation, yet allows for the beneficial shock-absorbing rotational movement of the latch to the strike. This use of pressure-actuated keepers eliminates the need for the prior art latch knob and thus also eliminates the subjectivity associated with determining the proper degree of torque required to sufficiently secure the latch to the strike under a range of conditions.

Claims

1. An improved latch for the corner structures of overhead frames, said corner structures being of the type comprising a length of tubular material formed into a right angle, said right angle comprising a vertical leg and a horizontal leg, the ends of said tubular material forming sockets oriented at 90 degrees to one another, each of said sockets capable of receiving a side of an overhead frame, said corner structures also comprising secondary fastener components affixed to said corner structures, said secondary fastener components comprising a latch retainer, a strike retainer, and a latch assembly, (a) said latch retainer comprising a first section of flat, rigid material having an upper face and a lower face, said latch retainer having a predetermined length and a width substantially equal to or less than the outside diameter of said tubular material of said latch corner and comprising a first threaded bore therethrough at a predetermined location, said latch retainer permanently affixed to said vertical leg of said latch corner in an orientation that is parallel to said horizontal leg of said latch corner, said lower face oriented toward said horizontal leg and at such a distance away from said horizontal leg that a swing side may be placed between said lower face and the upper surface of said horizontal leg, (b) said strike retainer comprising a second section of flat, rigid material having an upper face and a lower face, said strike retainer having a predetermined length and a width substantially equal to or less than the outside diameter of said tubular material of said strike corner and comprising a second threaded bore therethrough at a predetermined location, said strike retainer permanently affixed to said vertical leg of said strike corner in an orientation that is parallel to said horizontal leg of said strike corner, said lower face oriented toward said horizontal leg and at such a distance away from said horizontal leg that a swing side may be placed between said lower face and the upper surface of said horizontal leg, (c) said latch assembly comprising (1) a notched latch, said latch constructed of a third rigid material of predetermined size and shape and comprising a bolt bore therethrough near one end of said latch and an elongated notch therethrough of a predetermined size and shape near the other end of said latch, said latch being moveably fastened to said latch retainer by (2) a latch bolt, said latch bolt passing through said bolt bore of said latch and being joined to said latch retainer so that said latch is capable of being moved radially around a central axis of said latch bolt, the improvement of the present invention comprising (a) a strike, said strike comprising a predetermined size and shape relative to said size, shape and orientation of said latch so that a vertical disengagement of said latch from said strike is precluded; said strike being joined to said strike retainer and further being of a size and orientation so that said elongated notch of said latch is capable of radially engaging and radially disengaging from said strike when said corners are together positioned in a bundled orientation; said improvement further comprising (b) a latch keeper, said latch keeper being joined to said latch and comprising a moveable, pressure-actuated barrier constructed of a material capable of resisting a predetermined amount of radial force against said latch keeper, said latch keeper being located in a predetermined orientation relative to said strike when said strike is fully seated into said notch of said latch so that when said strike is fully seated into said notch of said latch, the resistance to said predetermined amount of radial force by said keeper against said strike is capable of holding said latch into contact with said strike, and so that said latch keeper is capable of allowing disengagement between said latch and said strike when a force greater than the resistance to said predetermined amount of radial force by said keeper is radially applied to said latch, whereby said bundled orientation of said overhead frames is maintained without the necessity of a latch knob and a related, subjective requirement of latch knob torque by an end user, thereby precluding an inadvertent separation of said frame components.

Description

DRAWINGSFIGURES

(1) FIG. 1Fully assembled frame with prior art corners

(2) FIG. 2Minimally disassembled frame in bundled configuration

(3) FIG. 3Detail of prior art corners; unlatched

(4) FIG. 4Prior art corners in latched position

(5) FIG. 5APreferred latch keeper; fully seated on strike

(6) FIG. 5BPreferred latch keeper; disengaging from strike

(7) FIG. 6Notched latchtop view

(8) FIG. 7Latch and keeper; exploded view

(9) FIG. 8Preferred Latch and Keeper; mounted

(10) FIG. 9Alternate preferred embodiment

(11) FIG. 10AAlternative latch

(12) FIG. 10BAlternative latch; exploded

(13) FIG. 10CAlternative latch; closed

(14) FIG. 10DAlternative Latch; open

(15) FIG. 11Alternative latch; mounted

(16) FIG. 12A2nd alternative latch with over-strike keeper

(17) FIG. 12B2nd alternative latch; side view

DRAWINGREFERENCE NUMERALS

(18) 20Swing Sides 21Main Sides 22Latch Corner 23Strike Corner 24Mounting Ears 26T-Handle Tension Bolts 28Latch Retainer 30Strike Retainer 32Notched Latch 33Latch Notch 34Latch Shoulder Bolt 35Latch Bolt Bore 36Strike 38Latch Knob 40Latch Keeper 42Keeper Tab 43Tab Void 44Boss 46Preferred Latch 48Boss Bore, countersunk 49Boss Screw 50Strike 54Alternate Keeper 56Latch Shell 58Latch Bolt Bushing 60Alternative Latch 62Pin Bore 64Lever Slot 66Latch Pin 67Thumb Lever 68Lever Bore 70Spring 72Pin Retainer Screw 802nd Alternative Latch Keeper 81Keeper Fastener 82Keeper Tab

DETAILED DECRYPTIONPREFERRED EMBODIMENTFIGS. 5A-8

(19) FIG. 5A shows a latch keeper 40 formed of a material of acceptable elasticity which, when joined to a latch 46, provides a movable, pressure-activated barrier into a latch's notch 33. The outer perimeter of keeper 40 and the rightmost half of the keeper's notch 33 perimeter match those of notched latch 46 of FIG. 6. A latch bolt bore 35 of keeper 40 is identical in size and relative orientation to the latch bolt bore 35 of latch 46. Positioning bosses 44 are located on the upper surface of keeper 40, as shown, and are sized and oriented to fit precisely into boss bores 48 of latch 46 when keeper 40 and latch 46 are joined as indicated in FIG. 7. Each of the bosses 44 include a bore of predetermined size through their central longitudinal axis to accommodate boss screws 49, as also in FIG. 7.

(20) In FIG. 5A, a cross section of a strike bolt 50 is shown as fully seated into notch 33. A keeper tab 42 is formed as part of keeper 40 as shown. Tab 42 provides the pressure-activated barrier into notch 33 as previously noted. Keeper and tab 40/42 are constructed of a material capable of resisting a predetermined amount of radial force so that when strike 50 is fully seated into notch 33, a resistance to force by tab 42 against strike 50 is capable of holding strike 50 into notch 33 until a greater force to disengage the latch is applied. Tab 42 is constructed in such a shape so that when keeper 40 is fully seated onto strike 50, tab 42 protrudes into notch 33 a predetermined distance and rests at a predetermined distance from strike 50. A tab void 43 is also shown. Void 43 is sized so that it is capable of fully receiving tab 42 when tab 42 is flexed aside as it passes by strike 50 during latching or unlatching, as indicated in FIG. 5B.

(21) FIG. 6 shows the preferred notched latch 46. As noted, bores 48 communicate with bosses 44 of keeper 40 when latch 46 and keeper 40 are mated to one another as indicated in FIG. 7. Bores 48 are countersunk to receive countersunk boss screws 49 so that the tops of screws 49 are flush with or below the upper surface of latch 46 when screws 49 are driven into bosses 44. The latch bolt bore 35 is sized to accommodate a latch shoulder bolt 34, as shown in FIG. 8, so that latch 46/40 is capable of rotational movement around the shoulder of bolt 34 when bolt 34 is joined to latch retainer 28. Notch 33 is sized to receive strike 50 and is located at a predetermined distance from bore 35 so that when the components of a minimally disassembled frame are bundled together, latch 46/40 is capable of rotating into a position in which strike 50 is fully seated into notch 33. In FIG. 8, due to the absence of latch knob 38, a shoulder bolt 50 is chosen as a strike to prevent latch 46/40 from vertical disengagement, or lifting off of strike 50 when strike 50 is radially engaged and fully seated.

OperationPreferred EmbodimentFIGS. 2, 8

(22) Components of a minimally disassembled overhead frame are bundled together as shown in FIG. 2. Latch and keeper 46/40 are rotated, as in FIG. 8, onto strike 50 until strike 50 is fully seated into notch 33 and behind keeper tab 43 (not seen). To release latch 46/40, the latch is pushed away from strike 50 until it is clear of the strike.

Alternate Preferred EmbodimentDescription and OperationFIGS. 9, 8

(23) FIG. 9 shows an alternate latch/keeper embodiment in which a keeper 54 is partially encapsulated within a latch shell 56. Latch shell 56 is of identical outer dimensions as latch 46 and retains the same latch bolt bore diameter 35 and position, and the same notch size 33 and position. Shell 56 is milled, cast, or otherwise formed with an outer perimeter as shown and is of a predetermined material having a composition so that keeper 54 is protected from and subsequently capable of withstanding a predetermined amount of force without undue distortion or breakage. Keeper 54 incorporates all elements of keeper 40 with the exceptions of having a smaller outer perimeter sized to fit into shell 56; a larger latch bolt bore 35 to receive a latch bolt bushing 58 that is joined to, cast or milled into shell 56; and elimination of bosses 44. Shell 56 and keeper 54 are secured to one another with countersunk latch screws (not shown) or other fasteners through bores 48 in the shell. Latch 56/54 and strike (not shown) are joined to retainers 28 and 30 in the same manner as the preferred embodiment. Operation is identical to that of the preferred embodiment in FIG. 8.

2nd Alternative EmbodimentDescriptionFIGS. 10A-10D

(24) FIG. 10A shows an exploded view of an alternative latch 60 and strike bolt 50 in position to be fastened to overhead corners. Latch 60 is joined to latch retainer 28 by shoulder bolt 34. Bore 35 in latch 60 is of a size that when bolt 34 inserted into bore 35 and threaded into retainer bore 34, latch 60 is capable of pivoting around bolt 34. A notch 33 is formed into latch 60 and is of such a size and is of such a distance from bore 35 that notch 33 is capable of pivoting onto and engaging with strike shoulder bolt 50 when the overhead frame components are bundled together as in FIG. 2.

(25) In FIG. 10B, the alternative latch 60 is shown in an exploded view. A latch 60 is formed with notch 33 and bore 35 as described above. A horizontal pin bore 62 is formed as shown. A lever slot 64 is formed above bore 62 and extends down into bore 62. Latch pin 66, sized to fit bore 62, is inserted into bore 62. Thumb lever 67, having a threaded lower end, is placed through 64 and is mated with threaded bore 68 of pin 66. Spring 70, also sized to fit bore 62, is then placed into bore 62. Pin retainer screw 72 is threaded into a threaded portion of bore 62 to retain spring 70 and pin 72.

2nd Alternative EmbodimentOperationFIGS. 10C, 10D, 11

(26) With latch 60 in closed position as in FIG. 10C, thumb lever 67 is retracted away from notch 33, as in FIG. 10D, until pin 66 is fully retracted. With pin 66 fully retracted, latch 60 is pivoted, as in FIG. 11, onto strike bolt 50 until notch 33 is fully engaged with strike 50. Thumb lever 67 is then released, and holds latch 60 captive onto strike 50.

3rd Alternative EmbodimentDescriptionFIGS. 12A, 12B

(27) In FIG. 12A, an alternative embodiment latch keeper is illustrated showing a latch keeper embodiment 80 mounted to a notched latch 32 by fasteners 81 and centered over notch 33. Keeper 80 is constructed of a predetermined material capable of resisting a predetermined amount of radial force so that when strike 50 is fully seated into notch 33, a resistance to force by tab 82 against strike 50 is capable of holding strike 50 into notch 33 until a greater force to disengage the latch is applied. In FIG. 12B, Keeper tab 82 is shown as extending out from keeper 80 and over a leading edge of strike 50. Keeper 50 and tab 82 are of a predetermined size and shape to fully receive strike 50 into notch 33, and to retain strike 50 into notch 33 of latch 32.

3rd Alternative EmbodimentOperationFIGS. 2, 12A, 12B

(28) Components of a minimally disassembled overhead frame are bundled together as shown in FIG. 2. Latch and keeper 80/32 are rotated, as indicated in FIG. 12A, onto strike 50 until strike 50 is fully seated into notch 33 and behind keeper tab 82. To release latch 80/32, the latch is pushed away from strike 50 until it is clear of the strike.

(29) Ramifications

(30) Thus the reader will see that the improved latch of the present invention reduces the possibility for a bundled overhead frame to become unlatched from shock or vibration due to insufficient torque of a prior art latch knob, and that the improved latch reduces the elapsed time for securing bundled frame components. While my above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible.

(31) For example, In FIG. 8, a shoulder bolt 50 is chosen as a strike to prevent vertical disengagement, or lifting off of latch 46/40 from strike 50 when strike 50 is radially engaged and fully seated. Other means of preventing vertical disengagement are possible, such as a bore through a strike and a pricket joined to a latch capable of communicating with the strike bore.

(32) The specification describes a notched latch being retrofitted with a latch keeper. This is due to current material availability regarding both adequate strength of a latch and required elasticity of the latch keeper. It is conceivable that a single material would adequately perform both duties, and thus provide a savings of time to manufacture and a reduction in the types and quantities of materials required for manufacture.

(33) The 2nd alternative embodiment illustrates a latch pin of specific shape. The given shape requires manual retraction of the pin in order to properly fasten to the strike bolt. It is possible that a latch pin having a beveled end (similar to the latch bolt on a door knob) would be capable of retraction by way of simple force of the latch pin against the strike without a need for pin retraction via the thumb lever. Such an improvement would enhance and speed the fastening process.

(34) Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.