Locking Connection For Supporting Grid Systems

Abstract

A first support member having a web with a slot therein and a second support member having a web upstanding from a pair of laterally extending support flanges and a locking connector formed integral with the web and extending axially therefrom for insertion in the slot. The connector has a locking tab engageable behind one side of the first support member web. The second support member has an offset end portion forming a continuation of the support flanges and adapted to overlie the first support member support flanges. The offset portion is provided with a transverse edge engageable with the other side of the first support member web to provide a rigid connection between the first and second support members. The offset portion has a thickness less than one-half the thickness of the support flanges with which it is integrally formed.

Parent Case Text

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a continuation-in-part of Application Ser. No. 806,977, filed Mar. 13, 1969 on a Locking Connection for Supporting Grid Systems now U.S. Pat. No. 3,584,904.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to structural connector elements and, more particularly, to rigid locking connections between support members used in supporting grid systems.

While not limited thereto, the present invention is particularly adapted for use in ceiling tile supporting grid systems of the type comprising a plurality of parallel spaced main grid members and cross grid members extending transversely between the main grid members and having end portions insertable through said main grid members and interlocking therewith.

Prior to the invention claimed and disclosed in application Ser. No. 806,977, these intersecting grid members often were provided with locking connectors having slots, notches or hooks intended to lock the grid members in place. Others employed short, resilient fingers stuck out from the body of the connector forming an opening so that the fingers could be cammed into the opening when inserted through a slot of a transversely extending main grid member and snapped into locking engagement behind the web portion of the main grid member when passed through the slot. Still others utilized separable locking connectors fixed to the end portions of the grid members. These locking connectors possessed certain disadvantages in that they often were relatively complicated or expensive, or excessive clearance was realized between the interlocking parts thereby effecting a loose and unsatisfactory connection between the grid members.

The invention claimed and disclosed in Application Ser. No. 806,977 obviated these disadvantages encountered in prior known locking connectors by forming locking connectors of a unitary, one-piece construction having a tab extending axially outwardly of the connector and reversely bent into a reinforced recess in the connector body to form a resilient locking member adapted to snap into firm locking engagement behind one side of the main grid support web to form a tight and rigid connection. However, to maintain the intersecting grid members in right angular relation, the tile supporting flanges of the cross grid terminated sufficiently inwardly of the locking connector member in an axial direction to accommodate the coplanar tile supporting flanges of the main grid member and abut the same with a tight fit. It can be appreciated that in such a connection, the width of the main grid member tile supporting flanges must be maintained within close tolerances to provide a tight, flush fit with the recessed ends of the cross grid member tile supporting flanges. Since these flanges are roll formed, the problem of maintaining accurate close tolerances is compounded and meticulous and diligent quality control must be exercised to maintain such flanges within these close tolerances. It is desirable, therefore, to eliminate the problem of maintaining the width of the tile supporting flanges within such close tolerances.

It has been proposed to offset the cross member of tile supporting flanges so as to rest upon the main grid member tile supporting flanges in the assembled relation. However, this poses a problem because the thickness of the reversely bent flanges causes the tiles to be tilted and inclined on the supporting flanges. This not only presents an uneven and irregular ceiling surface having sound and heat conducting openings therein, but detracts considerably from the decor of the ceiling surface.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a locking connection between intersecting grid members retaining the advantages found in the locking connector of Ser. No. 806,977 without requiring the maintaining of close tolerances in roll forming the main grid flanges.

The improved connection of the present invention is characterized by the provision of an offset portion located at opposite ends of a cross grid member having a flat edge engageable with the web portion of the intersecting main grid member. The offset portion has a thickness of less than one-half the thickness of the tile supporting flanges to minimize the tilting disposition of the tiles on the supporting flanges of the intersecting support flanges. The flat terminal edge of the offset portion is spaced from the cross grid member locking connector substantially the thickness of the main grid member web portion secured therebetween.

The foregoing and other objects, advantages and characterizing features of the present invention will become clearly apparent from the ensuing detailed description of an illustrative embodiment thereof, taken together with the accompanying drawings wherein like reference characters denote like parts throughout the various views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, perspective view of intersecting grid members incorporating the rigid locking connection of this invention;

FIG. 2 is a view similar to FIG. 1, but with the members disassembled;

FIG. 3 is a side elevational view, on an enlarged scale, of a supporting grid member incorporating the offset tile supporting flanges of this invention, being broken away for ease of illustration;

FIG. 4 is an enlarged, fragmentary, horizontal sectional view of the assembled members taken about on line 4--4 of FIG. 1;

FIG. 5 is a fragmentary, vertical sectional view thereof taken about on line 5--5 of FIG. 1;

FIG. 6 is a fragmentary, vertical sectional view thereof on a further enlarged scale, taken about on line 6--6 of FIG. 4;

FIG. 7 is a view similar to FIG. 6 but with the locking connectors removed; and

FIG. 8 is a fragmentary side elevational view of the offset supporting flange.

DETAILED DESCRIPTION OF THE PREFERRED FORM

Referring now in detail to the illustrative embodiment shown in the drawings, FIG. 1 shows a ceiling tile supporting grid system incorporating locking connectors of the present invention and comprising a main T support member, generally designated 10, detachable connected to a pair of cross T support members, generally designated 12. The main T member 10 can be conveniently fabricated from a single piece of any suitable material, preferably an inexpensive, lightweight metal such as soft steel for example, and is formed to provide a generally vertical web portion 14 upstanding from laterally projecting, tile supporting flanges 16 on opposite sides thereof and surmounted by a generally box-shaped, longitudinally extending, reinforcing member 18.

Web 14 is provided at spaced intervals with rectangular, normally vertical slots 20 for reception of the locking connectors of cross T members 12, only one such slot being illustrated. Slots 20 are generally H-shaped, being formed with downwardly and upwardly projecting tabs 22 and 24, respectively, at the top and bottom of the slot (FIG. 7) which serve as partitions or separators between the two cross T members 12 in the assembled joint.

Cross T members 12 can be similarly fabricated from a single piece of any suitable material, such as soft steel by way of example, and formed to provide a normally vertical web portion 26 upstanding from laterally projecting, tile supporting flanges 28 and surmounted by a generally flat, longitudinally extending, reinforcing member 30. It should be appreciated that reinforcing members 18 and 30 can take various shapes in transverse cross-section, such as a flat horizontal strip, a reinforced flat vertical edge having a thickness approximately twice that of the web portion, or a curved or rounded bulb shape, as desired.

Cross T members 12 are provided at their opposite ends with locking connectors, generally designated 40, extending from said opposite ends of each cross T member 12 and formed integral therewith. It should be noted that connectors 40 at opposite ends of cross T member 12 are offset and oriented in opposite lateral directions. As shown in FIG. 3, connectors 40 each include a tongue, generally designated 42, laterally offset from web 26 and projecting axially beyond the end of cross T member 12. A mechanical reinforcement is provided for each connector in the form of a channel 44 having a web body 46 and opposed longitudinally extending beads 48 and 50 defining a recess 52 therebetween. The leading edges of beads 48 and 50 are rounded, as shown at 60 and 62, to facilitate insertion of connector 40 into slot 20 of main T member web portion 14. To further facilitate continued insertion of connector 40 into slot 20, bead 50 is slightly tapered at its upper edge 51 longitudinally toward the leading edge thereof as shown in FIG. 3. Beads 48 and 50 are curved in transverse cross section so that the opposite sides thereof engage the sides of slot 20 and tabs 22, 24 to form a tight connection and prevent rotation of twisting of connector 40 within slot 20, as shown in FIG. 6. A small slot 53 is formed at the rear end of bead 50 for engaging the upper edge defining the slot portion between tab 22 and the side of slot 20 as will hereinafter become apparent.

A tab 54 initially extending axially beyond channel 44 and forming a continuation of web body 46 terminates in a generally flat edge 56. Tab 54 is bent back toward web body 46 with flat edge 56 adapted to engage behind main T member web portion 14 for locking engagement therewith in the assembled relation, as shown in FIG. 4. Tab 54 is partially disposed within recess 52 of channel 44 and is slightly inclined outwardly away from recess 52 and rearwardly toward web portion 26. Tab 54 is resiliently yieldable into recess 52, being held against complete collapse into recess 52 by means of a projection or stop 58 protruding from web body 56 toward tab 54. The material of connector 40 including tab 54 is relatively soft and ductile. However, stop 58 prevents tab 54 from being completely forced into recess 52 and taking a permanent set therein, thereby insuring an outwardly sloping disposition of tab 54 when assembled. Accordingly, tab 54 can be repeatedly installed, disconnected, and subjected to impact forces during handling an assembly without being sufficiently damaged to destroy its useful life.

A second channel member or elongated embossment 66 is disposed above channel 44 and oriented generally parallel thereto. Embossment 66 is provided with a web body 68 recessed laterally in the opposite direction from web body 46 of the adjacent channel 44 and forms an upward continuation of a portion of bead 50. Embossment 66 has a forward edge forming a stop shoulder 70 abutting web portion 14 of main T member 10 in the assembled relation. Embossment 66 extends inwardly of web portion 26 and tapers toward web portion 26 into which it finally merges. This embossment 66 not only provides a mechanical reinforcement for tongue 42 but also prevents lateral deflection of such tongue in the assembled connecting joint.

A significant feature of this invention is the provision of an offset portion 72 on the distal end of tile supporting flanges 28 adapted to overlie and rest on the tile supporting flanges 16 of main T support member 10. Offset portion 72 is less than one-half the thickness of flanges 28 and is offset upwardly to lie in a common plane with the upper folded portion of flanges 28 so as to present a substantially continuous coplanar surface as shown in FIG. 8. Cross T member 12 is fabricated from a suitable flat, one-piece blank with flanges 28 consisting of reversely bent portions 74 and 76 contiguously disposed and shaped by roll forming. Thus the thickness of flanges 28 is at least twice the thickness of the original blank or the summation of the thicknesses of portions 74, 76 and the inherent spaces or voids therebetween. Since offset portion 72 is a continuation of the underlying portion 74, its thickness is the same as said portion 74 or less than one-half the composite thickness of flanges 28. Offset portion 72 is formed by prenotching and then removing sections of material from opposite sides of the blank at the opposite ends thereof prior to the flange forming operation. After the flange forming operation, portion 72 is offset from the plane of portion 74 to the plane of portion 76 in a suitable press forming operation.

Offset portion 72 terminates in a flat terminal edge 78 which can have rounded corners and is adapted to abut and fully engage thereacross with web portion 14 of main T member 10. The spacing between edge 78 of offset portion 72 and the edge 56 of locking tab 54 is substantially the thickness of web portion 14 thereby insuring a rigid connection between main T member 10 and cross member 12 in the interlocking relation without any lateral rocking movement therebetween.

When assembling the grid system, connectors 40 are inserted into slots 20. In the illustrated joint, connectors 40 from the adjacent ends of aligned cross T members 12 extend side by side through web portion 14 of main T member 10, as shown in FIG. 4. Stop tabs 22 and 24 are vertically aligned, and divide each slot into a connected pair of slot portions, allowing connectors 40 to be inserted into each slot 20 from opposite sides of main T member web portion 14.

As each connector 40 is linearly inserted into its side of slot 20, tab 54 bears against the main T member web portion 14 defining that side of slot 20 and is cammed out of the way, into recess 52, permitting tab 54 to pass through slot 20. The resiliency of tab 54 permits deflection by such camming action. The forward end portion of tongue 42 is confined between tabs 22, 24 and the side of slot 20. During such tab insertion, offset portion 72 rides on the upper surfaces of flange 16 of main T member 10. Further insertion of connection 40 causes tab 54 to pass beyond web portion 14, allowing the resiliently displaced tab 54, urged by stop 58, to snap laterally outwardly from recess 52 to the locking position shown in FIGS. 4 and 5. Tab 54 is thereby positioned behind web portion 14 with tab edge 56 in locking engagement thereagainst, preventing withdrawal of connector 40 from slot 20 and holding the associated cross T member 12 connected to main T member 10. Because of the relatively long length of tab 54 as opposed to the short, struck-out fingers known in the prior art, tab 54 is cammed inwardly only slightly during insertion whereby upon outward urging thereof only a small, tolerable clearance exists between edge 56 and web portion 14, of negligible effect in achieving a tight assembled connection. In this locked position, terminal edge 78 of offset portion 72 engages against web portion 14 along with shoulder 70, to block further insertion of connector 40. The spacing between edge 78 of offset portion 72 and edge 56 of tab 54, is substantially the thickness of web portion 14 to insure a rigid connection between the intersecting T members 10 and 12 and maintain them in right angular relation.

As offset portion 72 of cross T member 12 rides on the upper surfaces of flange 16 of main T member 10 during the linear insertion of each connector 40 into its side of slot 20, connector 40 is urged upwardly against the upper edge of slot 20. The tapered edge 51 of bead 50 compensates for this and permits easier insertion of connector 40 into slot 20. Further insertion of connector 40 causes bead 50 to pass beyond slot 20 and slot 53 is advanced into registry with slot 20. The upward force exerted by offset portion 72 urges the bottom of slot 53 into engagement with the top edge of slot 20 to provide a second locking engagement between main T member web portion 14 and the rear end of bead 50 insuring that the associated cross T member 12 is positively held connected to main T member 10.

It should be appreciated that in forming grid members, the web portion is not always in perfect alignment along its entire length, i.e. it is not always centered true with respect to the edges of the grid member flanges. However, since the longitudinal or lengthwise spacing between edge 56 of tab 54 and edge 78 of offset portion 72 is constant in the present invention, a tight connection between T members 10 and 12 is insured regardless of the off-centered orientation of web portion 14 of main T member 10. Connector 40 of the other cross T member 12 is inserted through the other side of slot 20 in the same manner from the opposite side of main T member 10 to form a rigid joint. Web portions 26 of both cross T members 12 on opposite sides of main T member lie in a generally common plane. The engagement of edges 78 with web 14 maintains the intersecting members 10 and 12 in right angular relation, and together with shoulder 70 prevents vertical rocking of the cross T members.

In order to disconnect the grid member, bead 50 is depressed and tab 54 is resiliently displaced into recess 52 either by hand or with an appropriate tool to move edge 56 from behind main T member web portion 14. Tabs 54 face outwardly, as shown in FIG. 4, and are accessible for this purpose. With bead 50 and tab 54 depressed, connector 40 is easily withdrawn from slot 20 thereby disconnecting cross T member 12 from main T member 10.

From the foregoing, it is apparent that the objects of the present invention have been fully accomplished. By providing the cross support member with an integral offset portion having a transverse terminal edge adapted to engage the main support member web portion and spaced from the abutting edge of the locking connector substantially the thickness of each web portion, a strong, rigid joint is effected between the transversely extending support members. Moreover, the spacing between such transverse edge and the locking connector edge can be relatively easily maintained within close tolerances, as can the spacing between shoulder 70 and edge 56 thereby eliminating the much more difficult problem of maintaining close tolerances on the tile supporting flange width. Since the thickness of such offset portion is less than one-half the thickness of the tile supporting flanges, the difference in elevation is negligible in achieving a substantially continuous ceiling surface. Also, the urging of the bottom edge of slot 53 against the top edge of slot 20 by offset portion 72 provides a second locking engagement between the rear end of bead 50 and the main support member web portion 14 to further prevent withdrawal of connector 40 form slot 20.

A preferred embodiment of this invention having been disclosed in detail, it is to be understood that this has been done by way of illustration only.

Claims

What is claimed is:

1. A locking connection for supporting grid systems and the like comprising a first support member having flanges and a web upstanding therefrom provided with a slot; a second support member having flanges and a web upstanding therefrom provided with a locking connector extending axially therefrom and insertable through said slot; said locking connector having a portion engaging one side of said first support member web; said second support member having an end portion forming a continuation of said support flanges thereof and having a terminal edge below said locking connector portion engaging the other side of said first support member web; said locking connector having a stop shoulder above said locking connector portion engaging said other side of said first support member web above said end portion terminal edge and substantially vertically aligned therewith.

2. A locking connection according to claim 1 wherein said end portion has a thickness substantially less than the thickness of said flanges of said second support member.

3. A locking connection according to claim 1 wherein said end portion has a thickness less than one-half the thickness of said flanges of said second support member.

4. A locking connection according to claim 1 wherein said end portion has a thickness no greater than one-half the thickness of said flanges of said second support member.

5. A locking connection according to claim 1 wherein said end portion is offset and overlies a flange of the first support member.

6. A locking connection according to claim 1 wherein the spacing between said end portion terminal edge and said locking connector portion is substantially the thickness of said first support member web.

7. A locking connection according to claim 1 wherein said locking connector is provided with a bead along one longitudinal edge thereof, said bead having a tapered edge inclined toward the free end of said bead.

8. A locking connection according to claim 7 wherein said bead is provided with a slot at the end remote from said free end.

9. A locking connection according to claim 1 wherein the spacing between said end portion terminal edge and said locking connector portion is substantially the thickness of said first support member web; said end portion being offset and adapted to overlie a flange of the first support member; said end portion having a thickness substantially less than the thickness of said flanges of said second support member; a tapered bead along the outer longitudinal edge of said locking connector inclined toward the free end of said locking connector; the other end of said bead terminating in a slot.