US3270479A

US3270479A - Suspension grid system for a ceiling construction

Info

Publication number: US3270479A
Application number: US301146A
Authority: US
Inventors: Roger N Weinar
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-08-09
Filing date: 1963-08-09
Publication date: 1966-09-06
Anticipated expiration: 1983-09-06

Description

Sept. 6, 1966 R. N. WEINAR 3,27

SUSPENSION GRID SYSTEM FOR A CEILING CONSTRUCTION Filed Aug. 9, 1963 5 Sheets-Sheet. 1

r, we W zrneys R. N. WEINAR Sept. 6, 1966 SUSPENSION GRID SYSTEM FOR A- CEILING CONSTRUCTION Filed Aug. 9, 1963 5 Sheets-Sheet. 2

INVENTOR.

im/j w megs R. N. WEINAR Sept. 6, 1966 SUSPENSION GRID SYSTEM FOR A CEILING CONSTRUCTION Filed Aug. 9, 1965 5 Sheets5heet 3 INVENTOR.

United States Patent 3,270,479 SUSPENSION GRID SYSTEM FOR A CEILING CONSTRUCTION Roger N. Weinar, 129 San Clemente Drive, Oxnard, Calif. Filed Aug. 9, 1963, Ser. No. 301,146 8 Claims. (Cl. 52-667) This invention relates to a suspended grid for a ceiling construction and more particularly to the attachment of cross Ts to the perimeter molding and to the main Ts.

One of the objects of the present invention is to provide cross Ts which can be rapidly and securely fastened at their opposite ends to perimeter molding or main Ts and which will adequately withstand the load, such as ceiling panels and the like, imposed upon the cross Ts.

Another object of the invention is to provide such a mounting for the ends of cross Ts which does not involve any fastening members other than the materials of the Ts and perimeter molding itself.

Another object is to provide such a mounting for the ends of cross Ts which does not involve any tools used in the actual attachment of the cross Ts to the main Ts or perimeter molding, it being merely necessary to twist the ends of the cross Ts in opposite directions, aline the same and release the cross Ts.

Another object of the invention is to provide such a mounting for cross Ts in which the ends of the cross Ts can be readily formed in the field by the use of a suitable machine.

Another object is to provide such a mounting for cross Ts which places the entire ceiling grid, composed of the connected perimeter molding, main Ts and cross Ts, under stress, thereby to provide freedom from noise, such as rattling in response to extraneous vibrations, or noise coming from expansion and contraction of the grid due to temperature changes.

Another object of the present invention is to provide a mounting for the opposite ends of cross Ts which permits the cross Ts to be arranged in longitudinal alinement, with each pair of opposing ends secured to the web of a common main T.

Another object of the invention is to provide a simple, low cost and secure splice plate between abutting ends of the main Ts.

Another object of the invention is to provide such a splice plate between the abutting ends of the main Ts which does not require any fastening devices other than those which are integral with the splice plate and main Ts themselves.

Another object is to provide such a splice plate for the abutting ends of main TS and does not require any tools for applying the splice plates to the abutting ends of the main Ts.

Other objects and advantages of the invention will be apparent from the following description and drawings in which:

FIG. 1 is a fragmentary perspective view of a portion of the grid structure for a ceiling, illustrating the perimeter molding, a main T and a cross T, the latter being secured to the main T and perimeter molding in accordance with the present invention.

FIG. 2 is a perspective view of a cross T in its normal unstressed state, illustrating the helical form of the web and flanges concentric with the longitudinal axis of the T.

FIG. 3 is an enlarged exploded perspective view of one end of a cross T and a socket or offset portion in the web of a main T for receiving the same to secure the cross Ts to the main Ts.

FIG. 4 is a transverse section through one end of a cross T before insertion into the sockets or offset portions of a main T.

FIG. 5 is a view similar to FIG. 4 illustrating the cross T after insertion into the sockets or offset portions and fully fastened in position.

FIG. 6 is a fragmentary vertical section taken on line 66, FIG. 1 and also showing the ceiling panels supported on the bottom flanges of the main Ts.

FIG. 7 is a fragmentary vertical sectional view taken on line 7-7, FIG. 6.

FIG. 8 is an exploded perspective view of a splice for opposing abutting ends of the main Ts.

FIG. 9 is an enlarged vertical sectional view taken on line 99 of FIG. 1 and showing the splice in cross sec-tion and in particular illustrating the detents for retaining the splice plate in position.

In the accompanying drawings the ceiling grid construction is shown as composed of a perimeter molding 20 which forms the margin of the entire grid; main Ts 21 connected with the perimeter molding in any conventional manner (not shown); splice plates 22 connecting abutting ends of the main Ts when required; and cross Ts 24, the opposite ends of which are fastened to the main Ts or perimeter molding in accordance with the present invention.

The perimeter molding 20 of the grid structure is shown as comprising a series of sheet metal bars each of which is generally L-shaped in cross section having a vertical web 30 and an integral flange 31 forming a horizontal continuation of the lower edge of this web, the opposite or upper edge of the web 30 being preferably beaded or folded over as indicated at 32 and the outboard edge of the flange 31 also preferably being beaded or folded over as indicated at 33. This represents a standard construction of the bars forming perimeter molding of the grid of a supported ceiling.

The main Ts 21 are also shown as being of conventional form and as each made of a sheet of metal including a vertical web 35, the upper edge of which is in the form of an integral tube 36 and the lower edge of which is continued horizontally to form a horizontal flange 38. The outboard edge of this horizontal flange 38 is continued to form a bottom plate 39 which extends along and in contact with the bottom face of the flange 39 beyond the web 35 so as to form a flange 40 projecting from the bottom of the main T a distance substantially equal to the flange 38 so that the main Ts are generally in the form of a sheet metal bulb bar. The outboard edge of the flange 40 is preferably beaded or reversely bent as indicated at 41.

At intervals, below the tubular upper extremities, the main Ts 21 are provided with bores 42 through which suspension wires 43 can be inserted, these suspension wires suspending the grid structure from an overhead support (not shown).

The ceiling grid structure may include a number of main Ts 21 arranged end-to-end and their abutting ends, illustrated in FIGS. 1, 8 and 9, are connected together by a splice plate 22 embodying the present invention. For attachment of the splice plates each end of each main T is provided with a pair of

horizontal slots

45, 46. These slots are shown as being of generally the same length arranged one above the other in the web 35 at opposite ends of each main T 21, each slot 45 being arranged immediately under and parallel with the bulb or tube 36 of each main T and each slot 46 being arranged immediately above the flange 38 and parallel therewith.

Each splice plate 22 is shown as having a body in the form of a flat plate 50 adapted to rest against either face of the webs 35 of the abutting ends of the main Ts 21 as best illustrated in FIGS. 1 and 9'. This body is provided with a pair of upward extensions 51 at its opposite ends and which are of semicylindrical form. These semicylindrical upward extensions 51 are offset to the same side of the plane of the body 50 and are coaxial, their axis being generally coincident with the plane of the body. The internal diameter represented 'by the faces 52 is substantially equal to the outside diameter of the bulb or tube 36 of the main T 21. The length of each of the semi-cylindrical extensions 51 is slightly less than the length of a slot 45 and the distance between these semicyclindrical extensions 51 is slightly greater than the distance between the slots 45 when a pair of main Ts 21 are arranged in end-to-end abutting relation to each other.

The body 50 of each splice plate 22 is provided with a pair of spaced horizontal flanges 53 which extends in the same direction from the bottom edge of the body. Each of these horizontal flanges is of a length, measured parallel with the main Ts, somewhat less than the length of the slots 46 and the distance between these bottom flanges 53 is somewhat greater than the distance between the opposed ends of a pair of the slots 46 when their main Ts 21 are arranged in end-to-end abutting relation. An important feature also resides in the fact that these horizontal flanges are provided with at least one, and preferably a series, of upwardly projecting detent teats 54.

In erecting the main Ts and the perimeter molding constructed as above described the lengths of perimeter molding are positioned around the walls (not shown) of the enclosure and the main Ts 21 secured thereto in any conventional manner (not shown), the main Ts being suspended at suitable intervals by the wires 43. Where the main Ts 21 are required to abut each other, as illustrated in FIGS. 1 and 8, the splicing plates 22 are applied. This is done at each joint by inverting the splicing plate so that the semicylindrical extensions 51 of the plate projects downwardly, the concave faces 52 of these extensions then being brought against the side of the bulbs or tubes 36 at the abutting ends of the main Ts 21 with the outboard ends of these semicylindrical extensions 51 in line with a pair of slots 45 at the ends of the abutting Ts. The splicing plate 22 is then swung downwardly with the axis of its semicylindrical extensions 51 coincident with the axis of the two bulbs or tubes 36 of the two Ts, this causing the semicylindrical upward extensions 51 to thread through the slots 45 and embrace the opposite sides of the bulbs or tubes 36 of the abutting main Ts 21. In bringing the body 50 of the splice plate into contact with the faces of the webs' 35 of the abutting ends of Ts 21, the flanges 53 of the splicing plate pass through the slots 46 at the opposing ends of the two Ts. These slots are sufficiently wide to frictionally permit the passage of the series of teats 54 with hand pressure but distortion of these teats occurs so that when the splice plate 22 reaches the face-to-face position with the webs of its T bars, as illustrated in FIG. 9, these teats 54 spring up so as to retain the flanges 53 against accidental retrograde movement such as might be caused by vibration and the like.

To the grid of perimeter molding and main Ts assembled and supported as above, is then applied, the cross Ts embodying the present invention, although it will be understood that, where required, bridging Ts (not shown) could be employed, these bridging the spaces between the main Ts and being of the same general construction except as to weight. The term supporting bars as used in the accompanying claims is meant to include perimeter molding as well as main and bridging Ts.

The cross Ts made in accordance with the present invention are each preferably made of a single strip of sheet metal of a length to bridge the space between the webs 35 of the main Ts 21 and also to bridge each space between the outermost rows of main Ts 21 and the perimeter molding 20.

Each of these cross Ts comprises a web portion 60 the lower longitudinal edge of which is beaded or reversely formed as indicated at 62. The opposite or lower longitudinal edge of this web is continued laterally to form a perpendicular or horizontal side flange 65. The outboard edge of the side flange 65 is continued in the form of a bottom plate 69 which is arranged in face-to-face relation to the bottom of the flange 65 and projects beyond the web 60 to form a flange 70 on the opposite side of the web and the outboard edge of which is preferably beaded, as indicated at 71. The ends 73 of the web 60 of each cross or supported T 24 project beyond the ends of the flanges 65 and 70 thereof, a distance slightly greater than the width of the

side flanges

31, 38 and 40 of the perimeter molding 20 and main Ts 21. Each end edge 74 of the web 60 is formed to provide a pair of attaching

wings

75, 75, these attaching wings projecting perpendicularly from the corresponding end edge 74 but in opposite direction, one wing 75 projecting from approximately one half the end edge 74 perpendicularly in one direction and the other attaching wing 75 occupying approximately the other half of this end edge 74 and projecting in the opposite direction. These wings are preferably severally reinforced by strengthening ribs 76 which extend lengthwise of the web 60 and also extend around and form part of the base for each attaching wing as best shown in FIG. 3.

Each of the attaching Wings 75, 75 is preferably in the form of the segment of a circle, one generally straight edge of which is integrally attached to the end edge 74 of the web and the other straight edge 78 of which is at an included angle somewhat less than 90 with reference to the attached edge of each wing 75 and terminates in a circular outer edge 79 of the wing. This circular outer edge is shown as being concentric with a major or longitudinal central axis of the cross or supported T 24 and each edge 78 is generally parallel with a radius of this axis.

A feature of the invention-is that in the normal or unstressed condition of each supported or cross T 24 its web 60, flanges 65 and 70, and also the bottom plate 69 are of helical form concentric with a major or central longitudinal axis of the cross or supported T 24. The lead of the edges of the helix so formed is such that one end edge 74 of the web 60 is about 90 or at right angles to the opposite end edge thereof as best illustrated in FIG. 2.

At the place where the end of a cross T 24 is to be attached to the web of either the perimeter molding 20 or main T 24, this web is provided with a pair of laterally offset portions or pockets indicated generally at 80, each of which in plan is also in the form of a segment of a circle.

The pair of portions 80 of one sup-porting bar, such as a main T or the perimeter molding, are offset toward the companion pair of offset portions 80 of the other supporting bar for a common cross T. The outer circular perimeter or walls 81 of each pair of segmental-shaped offset portions 80 are generally concentric with each other about a common horizontal axis extending transversely of the web from which the pair of offset portions are formed. Each offset portion 80 terminates in a vertical edge 82 formed by a vertical slot 83 in the offset portion. The vertical edges 82 of each companion pair of offset portions 80 are preferably parallel but in otfset relation to each other and each edge is provided with a central indentation or nick 84 to accommodate the reinforcing ribs 76 of the supported cross Ts 24 as hereinafter described. Each offset portion 80 is provided with a horizontally extending straight .wall 85 which is radial with respect to the circular wall 81 and which forms a seat 86 for the edge 78 of a companion wing 75 of a supported T 24. The interior of each offset portion 80 conforms in shape and size to the wing 75 which it receives.

With the supporting bars of the ceiling grid, namely the perimeter molding 20 and main Ts 21, erected as previously set forth, the attachment of the cross Ts 24 in the grid is a simple matter. One end of one of the cross Ts 24 is brought up to one pair of offsets 80, say, a pair in the perimeter molding 20. The edges 78 of its pair of wings 75 at that end of the cross Ts are then brought to a vertical position; the cross T 24 is brought to a generally horizontal position; and the pair of Wings 75 are brought against the web of the perimeter molding 20 with their edges 78 alongside the vertical slots 83 in the pair of offset portions 80 of the perimeter molding, this position of the parts being illustrated in FIG. 4.

The supported cross T 2-4 is then turned about its longitudinal axis, which is now horizontal and generally concentric with the pair of segment-shaped offset portions 80 and segment-shaped wings 75, this turning being in a clockwise direction as viewed in FIG. 4. This causes the two wings 75, at the end of the cross T being fitted to enter the slots 83 of the pair of offsets 80 in the perimeter molding and their curved edges 79 to travel along the insides of the curved walls 81 until the leading edges 78 of the pair of wings engage and seat against the seats 86 of the walls 85 of the pair of offsets.

The clockwise movement of the supported cross T 24 in a clock-wise direction about its major or longitudinal axis as viewed in FIG. 4 is then continued through manual pressure applied from the opposite or now free end of the cross T. This results in a twisting of the cross T 24 about its major or longitudinal central axis in a direction opposite to the lead of the initially helical outboard edges of its web and flanges and 70. Such torsional movement is permitted by the ends of these flanges 65, stopping short of the flange 31 of the perimeter molding and is continued until the Webs and

flanges

60, 65 and 70 are not only brought into planar form but are twisted into a helix having a reverse bend as compared with the helical lead of the longitudinal edges in the unstressed condition of the cross T 24 as illustrated in FIG. 12.

This twisting is continued until the edges 78 of the pair of wings at the free end of the cross T 24 are brought to a substantially vertical position, following which these edges are brought alongside the slot 83 of the companion pair of offset portions 80 of the main T 21. The manual pressure holding this free end of the cross T 24 is now rel-axed, permitting the cross T to untwist itself about its major or longitudinal central axis, this untwisting causing the leading edges 78 of the two Wings 75 at the free end of the cross T 24 to enter the slots 83 of the companion pair of offset portions 80 of the main T .21. This untwisting continues with the curved edges '79 of these wings 75 riding along the inside faces of the walls 8 1 of these offset portions 80 until the leading edges 78 of these wings seat against the seats 86 of these offset portions 80 which halts the untwisting.

When this occurs the web 60 and flanges 65, 70 of the cross T 24 are in planar form, as compared with the initial or unstressed helical form illustrated in FIG. 2, and the bottom of the flat bottom plate 69 of the cross T 24 forms a coplanar continuation of the bottoms of the flange 31 and bottom plate 39 of the perimeter molding 20 and main T 21 to 'which it is attached. It will be noted, however, that the connections between the cross T 24 and its supporting

bars

20, 21 is still under torsional stress from the cross T because it has not fully untwisted to its relaxed helical state illustrated in FIG. 2. Accordingly the entire grid is under stress so that the parts are prevented from rattling or making other noise due to either external vibrations or to thermal expansion of the parts due to temperature changes.

After the ceiling grid is completed ceiling panels 90 can be mounted on the bottom flanges of the perimeter molding, main Ts and cross TS in conventional manner as illustrated in FIG. 1.

As illustrated in FIG. 1, it will be noted that the mounting for the cross Ts forming the subject of the present invention permits these cross Ts 24 to be mounted in end-to-end or straight line relations. Thus, as the place where a main T 21 is to have a pair of cross Ts 24 projecting in opposite directions in straight line relation to each other, two pairs of segmental-shaped offset portions are provided, one pair projecting from one side of the web 35 of the main T 21 and the other pair projecting from the opposite side of the web, all of these segmental shaped offset portions being concentric with a major axis of the two cross Ts 24 supported thereby.

Ceiling grid structures frequently include bridging Ts which for simplicity of illustration have not been shown. These are merely supporting Ts or bars between the main Ts 21 or between main Ts 21 and the perimeter molding 20 and to which corresponding ends of the cross Ts are secured as above described. The term supporting bars as used in the accompanying claims is meant to include such bridging Ts as well as the main Ts 21 and the perimeter molding 20.

.It will be seen that so far as the mounting of the cross Ts 24 is concerned, they extend transversely of and bridge the space between the vertical webs 30, 35 of the supporting

bars

20, 21 which supporting bars each has at least one supporting shoulder 86 offset toward the other supporting bar and arranged at the corresponding end of the cross T but offset from the major axis of the latter. It will further be seen that there are the projections 75 on the opposite ends of the supported T 24 which in the normal unstressed condition of the supported T are out of engagement with the supporting shoulder 86 and are positioned to be engageable with these supporting shoulders 86 to support the supported T 24 on the supporting

bars

20, 21 upon manually twisting the supported T 24 about its major axis and thereafter releasing said supporting T to effect engagement between said projections '75 and supporting shoulder 86.

From the foregoing it will be seen that the present invention accomplishes the objects and has the advantages initially set forth.

What is claimed is:

1. A grid for a ceiling, comprising a pair of generally horizontal and parallel spaced supporting bars each having a vertical Web and at least one horizontal side flange extending longitudinally thereof, a generally horizontal supported T extending transversely of and bridging the space between said vertical webs and having a vertical web and a side flange extending longituidnally thereof, said web of each supporting bar having at least one supporting shoulder offset toward the other supporting bar and arranged at the corresponding end of said cross T but offset from the major axis of said supported T, and projections on the opposite ends of said supported T offset from said major axis thereof and in the normal unstressed condition of said supported T being out of engagement with said supporting shoulders, said projections engaged with said supporting shoulders thereby causing the grid to be under stress; the supported T being assembled by manually twisting said supported T about said major axis and thereafter releasing said supported T in position to effect engagement between said projections and supporting shoulders.

2. A grid for a ceiling as set forth in claim 1 wherein there are a pair of said shoulders on the web of each supporting bar with the shoulders of each pair being on opposite sides of said major axis of said supported T, and wherein there are a pair of said projections at each end of said supported T with the pair of said projections at one end of said supported T exerting pressure against the mating pair of shoulders in the opposite rotative direction of the supported T about its axis from the pressure exerted by the pair of projections at the opposite end of the supported T against the pair of shoulders mating therewith.

3. A grid for a ceiling, comprising a pair of generally horizontal and parallel spaced supporting bars each having a vertical web and at least one horizontal side flange extending longitudinally thereof, the webs of said pair of supporting bars having supporting shoulders arranged generally in transversely alined relation to each other, a generally horizontal supported T having a maximum length substantially equal to the distance between said webs and having a vertical web and a side flange extending longitudinally thereof, said web and flange of said supported T, in the normal unstressed condition thereof, being of helical form generally concentric with a major axis of said supported T, and projections on the opposite ends of said supported T offset from the major axis thereof and engaged with said supporting shoulders thereby causing the grid to be under stress, and in the normal unstressed condition of said supported T being out of engagement with said supporting shoulders, the supported T being assembled by manually twisting said supported T about said major axis and thereafter releasing said supported T in position to effect engagement between said projections and supporting shoulders.

4. A grid for a ceiling having a pair of generally horizontal and parallel spaced supporting bars having vertical webs and side flanges extending longitudinally thereof, a horizontally and laterally offset portion in the web of one of said supporting bars projecting toward the other supporting bar and forming an upwardly facing shoulder, a portion in the web of the other of said supporting bars being horizontally offset toward the first mentioned offset portion and forming a second upwardly facing shoulder, a generally horizontal supported T substantially equal in length to the distance between said webs and having a vertical web and a side flange extending longitudinal, thereof, said web and flange of said supported T, in the normal unstressed condition thereof, being of helical form generally concentric with a major axis of said supported T, and projections on the opposite ends of said supported T offset from the major axis thereof and engaged with said supporting shoulder thereby causing the grid to be under stress, and in the normal unstressed condition of said supported T being out of engagement with said supporting shoulders, the supported T being assembled by manually twisting said supported T about said major axis and thereafter releasing said supported T in position to effect engagement between said projections and supporting shoulders.

5. A grid for a ceiling, comprising a pair of generally horizontal and parallel spaced supporting bars each having vertical webs and side flanges extending longitudinally thereof, a generally horizontal supported T substantially equal in length to and arranged across the space between said webs and having a vertical web and a side flange extending longitudinally thereof, said web and flange of said supported T, in the normal unstressed condition thereof, being of helical form generally concentric with a major axis of said supported T, a horizontally and laterally offset portion in the web of one of said supporting bars projecting toward the other of said supporting bars and having a marginal portion substantially coincident with said axis, a partion in the web of the other of said supporting bars being horizontally and laterally offset toward the first mentioned laterally offset portion and also having a marginal portion substantially coincident with said axis, a transversely extending wing at each end of said supported T, each of said laterally oflset portions having a marginal slot adapted to receive the corresponding wing when said supported T is manually twisted into a helical form reverse to its said helical form in its said unstressed condition, said wings engaged with said offset portions thereby causing the grid to be under stress; the supported T being assembled by manually twisting said supported T about said major axis -and thereafter releasing said supported T in position to effect engagement between said wings and offset portions.

6. A grid for a ceiling as set forth in claim 5 wherein each of said supporting bars and said supported T is made of sheet metal bent to form its web and flange.

7. A grid for a ceiling as set forth in claim 5 wherein each of said laterally offset portions is in the form of a segment of a circle generally coincident with said axis with said slot being provided in one radial wall thereof and with the other radial wall forming said seat.

8. A grid for a ceiling as set forth in claim 7 wherein said slot is upright and said seats face upwardly.

References Cited by the Examiner UNITED STATES PATENTS 1,803,995 5/ 1931 Chilton 287-53 2,433,902 1/ 1948 Henrichsen 105-182 2,689,630 9/1954 Drury 52-475 2,990,921 7/1961 Wilde 52-475 X 3,119,475 1/1964 Adams 52-475 X 3,138,227 6/ 1964 Gordon.

FOREIGN PATENTS 1,010,046 3/1962 France.

564,707 11/ 1932 Germany.

FRANK L. ABBOTT, Primary Examiner. RICHARD W. COOKE, JR., Examiner.

M. O. WARNECKE, Assistant Examiner.

Claims

1. A GRID FOR A CEILING, COMPRISING A PAIR OF GENERALLY HORIZONTAL AND PARALEL SPACED SUPPORTING BARS EACH HAVING A VERTICAL WEB AND AT LEAST ONE HORIZONTAL SIDE FLANGE EXTENDING LONGITUDINALLY THEREOF, A GENERALLY HORIZONTAL SUPPORTED T EXTENDING TRANSVERSELY OF AND BRIDGING THE SPACE BETWEEN SAID VERTICAL WEBS AND HAVING A VERTICAL WEB AND A SIDE FLANGE EXTENDING LONGITUDINALLY THEREOF, SAID WEB OF EACH SUPPORTING BAR HAVING AT LEAST ONE SUPPORTING SHOULDER OFFSET TOWARD THE OTHER SUPPORTING BAR AND ARRANGED AT THE CORRESPONDING END OF SAID CROSS T BUT OFFSET FROM THE MAJOR AXIS OF SAID SUPPORTED T, AND PROJECTIONS ON THE OPPOSITE ENDS OF SAID SUPPORTED T OFFSET FROM SAID MAJOR AXIS THEREOF AND IN THE NORMAL UNSTRESSED CONDITION OF SAID SUPPORTED T BEING OUT OF ENGAGEMENT WITH SAID SUPPORTING SHOULDERS, SAID PROJECTIONS ENGAGED WITH SAID SUPPORTING SHOULDERS THEREBY CAUSING THE GRID TO BE UNDER STRESS; THE SUPPORTED T BEING ASSEMBLED BY MANUALLY TWISTING SAID SUPPORTED T ABOUT SAID MAJOR AXIS AND THEREOF RELEASE SAID SUPPORT T IN POSITION TO EFFECT ENGAGEMENT BETWEEN SAID PROJECTIONS AND SUPPORTING SHOULDERS.