US3509673A

US3509673A - Modular partition wall system

Info

Publication number: US3509673A
Application number: US717498A
Authority: US
Inventors: Edward R Witkosky; Henry F Golder
Original assignee: Woodwork Corp of America
Current assignee: Woodwork Corp of America
Priority date: 1968-04-01
Filing date: 1968-04-01
Publication date: 1970-05-05
Anticipated expiration: 1987-05-05

Description

y 1970 E. R. WITKOSKY ET AL 3,509,673

MODULAR PARTITION WALL SYSTEM Filed April 1, 1968 4 Sheets-Sheet 1 L\ Y W NM 111/ 1 A 1 4 252:: R J RN RN \NWNW Ow QR Nb bw M QM imfm y 5, 1970 E. R. WITKOSKY ETAL MODULAR PARTITION WALL SYSTEM Filed April 1. 1968 4 SheetsSheet 2 E. R. WlTKOSKY ET MODULAR PARTITION WALL SYSTEM May 5, 1970 Filed April 1, 1968 5 m a F W 3 x w w 8 7 a 5 a 4 M 5 5 5 H fl w m 2 a 3 A. 2: A w\\w\w \m W fi K n 3 O W 6 m 9 ma 5 5 J 2 U2 Z 5 W a 5 F 1970 a. R. WITKQSKY ET AL 3,509,673

MODULAR PARTITION WALL SYSTEM Filed April 1, 1968 4 Sheets-Sheet 4 F155 Ma FIT-35 :1 I J82 3 95 676 515 l 5 9! United States Patent O 3,509,673 MODULAR PARTITION WALL SYSTEM Edward R. Witkosky, Chicago, and Henry F. Golder, Riverdale, Ill., assignors to Woodwork Corporation of America, a corporation of Illinois Filed Apr. 1, 1968, Ser. No. 717,498 Int. Cl. E04!) 2/08, 2/72; E04h 1/00 US. Cl. 52242 13 Claims ABSTRACT OF THE DISCLOSURE A modular partition wall system which includes a plurality of rectangular panels and five different types of interlocking components which are used in combination with the panels for the following purposes:

(1) To arrange two or more panels in alignment and in spaced relationship to one another with their adjacent vertical ends secured together by friction connector means which cooperate to form hollow post-like structures;

(2) To join the adjacent vertical ends of two panels which are aligned with one another to the adjacent vertical end of a single panel which is at right angles to the two aligned panels to form a T corner;

(3) To connect the adjacent vertical ends of two aligned panels with the adjacent vertical ends of two other aligned panels which are at 90 to the first pair of panels at the corner of four enclosures;

(4) To join the adjacent vertical ends of two panels which are at right angles to one another with the ends of the adjacent panels exposed, and conceal the exposed end with a corner closure member which frictionally engages with elements on the adjacent vertical ends of the two panels.

BACKGROUND OF THE INVENTION The art contains a wide variety of modular partition wall. systems which are used for dividing a large room into a number of smaller enclosures. In some cases only a single divider wall is required to divide a single room into two smaller rooms. In other cases there must be provision for walls to meet at right angles, either in a junction or an intersection, or for walls to provide a corner of an enclosure within the room. A modular partition wall system which is adequate to meet all the requirements of modern commercial and industrial building structures must be extremely flexible, and in view of the high labor costs involved in installing and removing partition walls the components must be capable of being both assembled and disassembled rapidly while affording structures which are strong and solid in use.

Other requisites of a modular partition wall system are that it be attractive in structure, and that all the necessary permutations and combinations for a flexible system be available with a relatively small number of basic components so as to reduce inventory and simplify the selection of components for a custom installation.

SUMMARY OF THE INVENTION In accordance with the present invention, a modular partition wall system includes rectangular panels each of which includes a rectangular wood frame having front and rear faces and vertical ends and horizontal ends, with parallel slots formed from end to end of one or both of the vertical ends. A panel body on the frame includes sound attenuating means and decorative sheet material which provides skins over both surfaces of the sound attenuating means and over the front and rear faces of the wood frame. Each of the slotted vertical ends of the rectangular wood frame is provided with a 3,509,673 Patented May 5, 1970 continuous, extruded metal connector strip which has a base with parallel ribs frictionally engaged in the slots in the vertical end of the panel to fixedly secure the connector strip to the vertical end. The connector strip has a generally planar outer surface, and a pair of rigid, integral friction flange means are formed on the outer sur-' face of the base where they may be engaged with connector elements having fingers which make a frictional interlocking engagement with a friction flange on the connector strip.

If two panels are to be connected in alignment with one another, both are provided with identical connector strips that have connector flanges with gripping ribs which extend toward the two surfaces of the panel and are engaged by fingers of connector elements which are positioned with their respective fingers extending toward one another and engaged with both gripping ribs on each of the panel connector strips. The connector elements have planar outer surfaces which are flush with the surfaces of the panels when assembled with the latter, and the adjacent panel vertical ends and friction connector elements cooperate to form a hollow enclosure between the adjacent vertical panel ends so that the enclosure may be used as a wireway if desired.

If a third panel is to be connected with the first two at right angles to them, to form a T-corner, one of the two friction connector elements is eliminated and the third panel has a vertical end which is adjacent the first two panels provided with a connector element which is structurally precisely like the one which is eliminated but for the fact that it has a pair of parallel ribs that frictionally engage the slots in the adjacent vertical end of the third panel.

If four panels are to "be joined at the intersection of four walls the arrangement is the same as just described for three panels, and in this case the second connector element of the straight wall assembly is also eliminated and the adjacent vertical edge of the fourth panel is provided with a connector element like that on the vertical edge of the third panel.

Where two panels are to be joined at right angles, the first panel is provided with a connector strip as originally described. A second panel is provided with a connector element which is mechanically like the connector element used in the three or four wall intersection, but which is structurally slightly different. When one finger on the connector element of the second panel is frictionally engaged with one friction flange of the connector strip on the first panel the two panels are secured together with their adjacent ends exposed. The open corner is then finished with a corner closure member which is an angle member with first and second legs at right angles to one another. A first leg is positioned parallel to the body of the connector member and has a finger which is identical with a finger on the connector member and is engaged with the second gripping rib on the first panel connector strip. The second leg of the corner closure member is provided with one friction flange means which is identical with those on the panel connector strip, and that one friction flange means is engaged with the second finger of the connector element on the end of the second panel. When assembled the corner closure member has the outer faces of its two legs flush with the outer surfaces of the two panels so as to provide an attractively finished corner.

In common with other modular panel systems, the system of the present invention utilizes a base structure including inverted channels on which the bottoms of the panels and connectors rest, so that the base structure provides a wireway for electrical utility installation. Likewise, as in other modular panel systems there is a generally conventional top finished assembly which encloses the upper ends of the panel and connector structure, and

which may be mounted on the ceiling if the panels are of full room height or which may be spaced below the ceiling if the panels form only a partial partition form of enclosure.

Likewise, the complete system includes panels which are of less than full height to aiford window openings or so that they may be surmouned by opaque or transparent glazed panels, full glazed panels may be substituted for the panels heretofore described, and the system also includes doors and door frames. However, all of the last mentioned elements are conventional components which are generally common to all modular partition wall systems, and accordingly they are not illustrated or described herein.

The principal object of the present invention, therefore, is to provide a modular partition wall system in which full flexibility for custom installation is possible with a relatively small number of stock components.

Another object of the invention is to provide a modu lar partition wall system in which all the connections between panels are afiorded by friction means so that, once the supporting mean is in place and brackets are secured to the walls for fastening the end panels of the layout, the entire wall system may be assembled without the use of tools except as a screwdriver may be needed to hang door hinges.

Yet another object of the invention is to provide a modular partition wall system which may be rapidly as sembled by relatively unskilled workmen, which is extremely rigid and solid when assembled, but which may be rapidly disassembled when it is necessary to change the partition arrangement in the space.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a horizontal sectional view of a panel wall system embodying the invention, with the panels broken to save space, and illustrates the four different types of connector assemblies and the five different types of connector components which are required to make such assemblies.

FIG. 2 is a fragmentary front elevational view, with parts omitted and parts broken away for clarity taken substantially as illustrated along the line 22 of FIG. 1;

FIG. 3 is a vertical section taken substantially as indicated along the line 33 of FIG. 1 with the panels broken to conserve space;

FIG. 4 is an end elevational view of a connector strip on an enlarged scale;

FIG. 5 is an end elevational view of a connector element on an enlarged scale;

FIG. -6 is an end elevational view of a connector element for a three wall or four wall intersection on an enlarged scale;

FIG. 7 is an end elevational view of a connector element for an outside corner intersection of two panels on an enlarged scale;

FIG. 8 is an end elevational view of a corner closure member on an enlarged scale;

FIG. 9 is a greatly enlarged detail illustrating the engagement between a connector strip rib and a connector element finger; and

FIG. 10 is an end elevational view of a panel member.

DETAILED DESCRIPTION Referring to the drawing in greater detail, and referring first to FIGS. 1 to 3, the modular partition wall sys tem of the present invention consists generally of supporting means, indicated generally at S; a panel and con nector system which forms the body of the wall, indicated generally at W, and consists of panels P1, P2, etc. and connector assemblies C1, C2, etc.; and upper channel means, indicated generally at U. As is customary in such systems, the supporting means S and the upper channel means U extend continuously beneath and above the body of the wall W, so as to support and conceal the lower and upper ends of the panels and connectors and give a finished appearance. Since the base means and the upper channel means are a part of the entire system, but are not a part of the invention, they will be described only in suflicient detail to provide an understanding of their function.

The supporting means S is best seen in FIG. 3 to include an extruded metal channel 20, modular lengths of which are positioned end to end on a strip of tape 21 which has pressure sensitive adhesive on both faces so as to adhere both to a floor F and the channel 20. A plurality of inverted U-shaped raceway members 22 having upwardly and outwardly inclined top flanges 23 are positioned at spaced intervals along the channel 20 to support the body of the wall W; and a pair of plastic molding strips 24 which extend continuously along the supporting means are formed to engage the top flanges 231 and be gripped between the upright walls 20a of the channel 20 and the side walls of the raceway members 22.

The upper channel means U consists of a single channel member 25 having a top 26 and sides 27. The channel member 25 is secured to the ceiling X of a room by means of a double adhesive strip of tape 28 which is like the previously described tape 21, and each of the channel walls 27 has a continuous guideway 27a to receive a decorative trim strip 29. The vertical length of the wall body W is sufliciently less than the distance from the tops of the raceways 22 to the top 26 of the upper channel U that its lower end W1 may clear the tops of the raceway flanges 23 when its upper end W2 is abutted against said top 26.

Referring now particularly to FIG. 1, it is seen that panels P1, P2 and P3 are joined by connector assemblies C1 and C2 in alignment with one another to provide a straight wall. Also secured to connector assembly C2 is a panel P4 which is at right angles to the panels P2 and P3. The panel P4 is joined by a connector assembly C3 with panels P5, P6 and P7 to provide a four wall intersection; while a connector assembly C4 joins panel P3 with a panel P8 to form an outside corner. Thus, FIG. 1 illustrates all of the panel connector arrangements of the present modular partition Wall system.

Each of the panels P illustrated in the drawings consists of a rectangular wood frame, indicated generally at 30, having a front face 31, a rear face 32, vertical ends 33 and 33a (FIG. 1), and horizontal ends 34 and 34a (FIG. 3). As best seen in FIG. 10 the vertical end 33, and in some cases also the vertical end 33a, are provided with parallel slots 35 which extend from end to end of said vertical end. Within the frame 30 is a mass 36 of sound attenuating material both surfaces of which are covered by solid panels 37, and skins 38 of decorative sheet material cover the panels 37 and the frame 30.

The first element of the connector means C consists of an extruded aluminum connector strip, seen in FIG. 4 and indicated generally at 40, which has a base 41 with a generally planar outer surface 42. A pair of parallel ribs 43 project from the under surface of the connector strip base 41 and are frictionally engaged with the slots 35 of the panel frame so that the connector strip is fixedly secured to a vertical end 33 or 33a of a panel and extends from end to end of said vertical end. With the exception of the panel P1, each panel has a connector strip 40 along each of its vertical ends, but this is not necessary for the panel P1 because its vertical end 33a which is adjacent a building wall Y is received in a vertically mounted channel 25 which is exactly like the channel 25 which is used on the ceiling X.

As best seen in FIG. 4 the connector strip 40 also includes a pair of rigid, integral friction flange means 44 which project from the outer surface 42 of the connector strip base and include parallel spacer portions 45 with oppositely extending gripping ribs 46 at the free ends of the spacer portions, the ribs 46 being substantially parallel to the planar surface 42 and having friction bosses 47 which project toward such planar surface. Each of the friction bosses 47 has a forward surface 48 which extends diagonally inwardly toward the planar surface 42, and an apex 49. Thus, the friction bosses of the gripping ribs may be firmly engaged with a complementary friction connector element, indicated generally at 50, as will be described in more detail.

Each of the friction connector elements 50 is best seen in FIG. 5 to include a body 51 which is substantially the same length as the vertical end of a panel, and a pair of parallel fingers 52 which are at the ends of the body and perpendicular to it. Each of the fingers 52 includes a base portion 53 having a planar outer face 54 which is seen in FIG. 3 to be positioned in facing engagement with the planar outer surface 42 of a connector strip 40 when the two parts are assembled. At the outer extremity of the finger base portion 54 is a shoulder 55 which extends away from the connector strip base 41 when the parts are assembled, so that the outer portion 56 of the finger is spaced from the connector strip base 41 when they are assembled. As seen in FIG. 3, each of the connector element fingers 52 is positioned and proportioned to extend into the space between a connector strip base 41 and a gripping rib 46; and each finger has at its free end an enlarged camming portion 57 which is best seen in FIG. 9 to include a diagonal forward camming surface 58 and a generally flat face 59. As a friction connector element 50 is slid into engagement with the connector strips 40 of two adjacent panels such as the panels P1 and P2, each diagonal forward camming face 58 engages the diagonal forward surface 48 of the gripping rib 46 so as to spring the fingers slightly outwardly as the parts are engaged, so that when the connector element 50 and the connector strip 40 are fully engaged there is a heavy frictional engagement between the apexes 49 of the connector strip bosses 47 and the finger surfaces 59.

As seen from the connector assembly C1 of FIG. 3, two connector elements 50 are used to make a connection between two panels which are aligned with one another, with the fingers 52 of the two connector elements 50 extending toward each other and engaging with the oppositely extending friction flange means 45 and gripping ribs 46 of the two panels. When assembled the connector element bodies 51 have their outer faces substantially aligned with the outer and inner faces 31 and 32 of the panels P1 and P2; and each of the connector elements 50 preferably has its body 51 provided with outwardly extending flanges 51a to receive a decorative trim strip 51b.

It is clear from the foregoing description of the connector strips 40 and the connector elements 50 that two panels P1 and P2 may be connected together in longitudinal alignment merely by mounting them with their upper ends extending into the upper channel U and their lower ends supported upon the raceways 22 and manually engaging the two connector elements 50 with the two connector strips 40 of the pannels. When assembled the parts are firmly held together to provide a very solid and rigid structure, but the parts may be readily disassembled by prying the connector elements 50 out of engagement with the connector strips 40.

Referring now to the connector assembly C2 of FIG. 3, and also to FIG. 6 of the drawings, where a three wall intersection is to be formed including the panel P2, the panel P3, and the panel P4, one of the connector elements 50 is eliminated and the panel P4, equipped with a connector element 60, is secured to the panels P2 and P3 in place of the eliminated element 50. Comparison of FIGS. 5 and 6 shows that the

connector elements

50 and 60 are mechanically identical insofar as their engagement with the connector strips 40 is concerned; but the element 60 lacks flanges such as the flanges 51a, and instead has a body 61 with ribs 61b which are seated in slots in the frame of the panel P4 so as to fixedly secure the element 60 to the panel.

Referring now to the four wall junction of FIG. 1 which is formed by the connector assembly C3, it includes the panel P4, a panel P5 aligned therewith, and a pair of panels P6 and P7 which are aligned with one another at right angles to the panels P4 and P5. The connector assembly C3 includes, on the pannels P4 and P5, connector strips and on the panels P6 and P7, connector elements 60. The engagement of the two connector elements with the two connector strips 40 locks the four panels together in a rigid assembly.

Finally, the connector assembly C4 joins the panel P8 and the panel P3 at right angles to one another in an outer corner structure which is strong, stable, attractive, and easy to assemble. That assembly requires a connector strip 40, a connector element indicated generally at 70, and a corner closure indicated generally at 80. As best seen in FIG. 7 the connector element 70 is substantially identical with the connector element 60, except that it has one finger 72 which is inset from the adjacent end of the connector body 71 so as to provide, in effect, an extension 710 of the body beyond the finger 72. The purpose of this change is to permit the corner closure member 80 to be engaged with the finger 72 and still have its

legs

181 and 281 aligned respectively with the outer faces of the panels P3 and P8.

Referring to FIG. 8, the corner closure member 80 is an angle member having a first leg 181 and a second leg 281. On the leg 181 is a single finger 82 that is functionally identical with the

fingers

52, 62 and 72 but differs structurally by reason of the fact that it has a base 83 which terminates generally flush with the leg 181. The base 83, however, is seen in FIG. 1 to have a planar outer face 84 which cooperates in the same way with the planar face 41 of the connector strip 40 as does the face 54 of the finger 52. The second leg 281 of the corner closure member 80 is provided with a single rigid, integral friction flange 184 which is identical with the friction flange 44 of the connector strip 40.

Thus, the corner closure member 80 is assembled with the connector strip 40 on the panel P3 and with the connector element 70 on the panel P8, as seen in FIG. 1, by moving the corner closure linearly toward the open end of the panel P8 to engage its finger 82 with the friction flange 44 of the connector strip 40 and to engage its friction flange 184 with the finger 72, in which position the leg 281 abuts against the end portion 710 of the connector element 70.

Because the

legs

181 and 281 of the corner connector 80 have exposed outer surfaces they are provided with

flanges

181a, 281a, and a double corner flange 182, so thatbthey may accommodate decorative strips 181b and 281 FIG. 1 also illustrates the fact that an open panel end, not secured to a wall, may be finished by using a channel member 25 like those which are used for the upper channel U and the wall connector. When used to finish the end of a panel the channel 25, in addition to the decorative strips 29 on its two sides, has a decorative strip 29a mounted in channels 2711.

Although not illustrated herein, where the top of a panel is to be below ceiling level, and particularly where it may be visible, the top of the panel is capped by a channel member 25 which is provided with a decorative strip 29a in the same manner as has just been described for an open panel end.

It is seen from the foregoing detailed description that with a relatively small number of extruded aluminum components, which are basically alike in structure, all

the necessary connector assemblies for a partition wall system may be made. 1

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, as some modifications will be obvious to those skilled in the art.

We claim:

1. A panel for a modular partition wall system comprising, in combination:

a rectangular wood frame having front and rear faces and vertical ends and horizontal ends, there being parallel slots from end to end of one of said vertical ends;

a panel body on said frame including sound attenuating means and decorative sheet material forming skins over said sound attenuating means and the front and rear faces of the wood frame to provide first and second panel faces; and

a continuous connector strip extending along said one vertical end, said connector strip having a base with parallel ribs frictionally engaging the slots in said vertical end to fixedly secure the strip to said end and having a generally planar outer surface, and a pair of rigid, integral friction flange means on the outer surface of the base, said flange means including parallel spacer portions extending outwardly from the base and gripping ribs at the outer ends of the spacer portions, said ribs being substantially parallel to the planar surface and having free ends which extend, respectively toward said first and second panel faces, there being a friction boss adjacent each of said free ends which projects toward said surface and extends a substantial distance along the vertical end of the panel.

2. A panel for a modular partition wall system comprising, in combination:

a rectangular frame having vertical ends and horizontal ends, there being parallel slots from end to end of one of said vertical ends; panel body mounted in said frame which includes first and second panel faces; and continuous connector strip extending along said one vertical end, said connector strip having a base with parallel ribs frictionally engaging the slots in said vertical end to fixedly secure the strip to said end and having a generally planar outer surface, and a pair of rigid, integral friction flange means on the outer surface of the base, said flange means including parallel spacer portions extending outwardly from the base and gripping ribs at the outer ends of the spacer portions, said ribs being substantially parallel to the planar surface and having free ends which extend, respectively toward said first and second panel faces, there being a friction boss adjacent each of said free ends which projects toward said surface and extends a substantial distance along the vertical end of the panel.

3. In a modular partition wall system which includes means for supporting the wall system on the floor of a building, a plurality of rectangular panels adapted to be mounted on said supporting means to provide room dividers, and connector means for securing panels together with adjacent vertical panel ends in predetermined spaced relationships, in combination:

a first panel which has first and second faces and a connector strip extending continuously along one of its vertical ends, said strip including a base with a generally planar outer surface covering the panel end, means fixedly securing the base to the panel end, and a pair of rigid, integral friction flange means on the outer surface of the base, said flange means including parallel spacer portions extending outwardly from the base and gripping ribs at the outer ends of the spacer portions, said ribs being substantially parallel to the planar surface and having free ends which extend, respectively toward said first and second panel faces, there being a friction boss adjacent each of said free ends which projects toward said surface and extends a substantial distance along the vertical end of the panel;

a friction connector element that includes a body which is substantially the same length as the vertical end of a panel, and a pair of parallel fingers integral with said body, each of said fingers being positioned and proportioned to extend into the space between a con nector strip base and a gripping rib, and each of said fingers extending a substantial distance along said body and having at its free end an enlarged camming portion that engages the friction boss on the gripping rib to spring the finger and the boss into firm frictionally interfitting engagement with one another, one of said connector elements being at the vertical end of a panel with its body normal to the base of the connector strip on the panel and a first of its fingers frictionally interfitted with a first gripping rib on said strip; and

second panel engaged with the friction connector element.

4. The combination of claim 3 in which the second panel is fixedly secured to the body of the connector element so as to be fixedly positioned at right angles to the first panel and form an open corner therewith, and in which there is a corner closure member comprising an angle member which is substantially the same length as the first panel and the body of the connector and has first and second legs at right angles to one another, said corner closure member having its first leg positioned parallel to the body of the connector member and having a finger on said leg which is identical with a finger on the connector member, said finger on said first leg being frictionally interfitted with the second gripping rib boss on the first panel connector strip, and the second leg of the corner closure member being provided with one friction flange means which is identical with those on the first panel connector, said one friction flange means having a gripping rib with a boss that is frictionally interfitted with the second finger of the connector element.

5. The combination of claim 3 in which the vertical end of the first panel has a pair of parallel slots from end to end, and in which the base of the connector strip has a pair of parallel ribs frictionally engaged in said slots to fixedly secure the strip to the panel end.

6. The combination of claim 3 in which each finger on the connector element has a base portion with a planar outer face that slidingly engages the planar outer surface of the connector strip base, and in which a shoulder at the outer extremity of said finger base portion extends away from the connector strip base and the outer portion of the finger is spaced from said connector strip base when assembled therewith.

7. The combination of claim 6 in which the camming portion of each finger includes a diagonal forward surface which carnmingly engages a complementary forward surface of the friction boss as the connector element is frictionally interfitted with the connector strip so as to spring the finger.

8. The combination of claim 3 in which the second panel has a vertical end in parallel spaced relationship to the one vertical end of the first panel, said second panel has fixedly secured to said vertical end a connector strip identical with that on said one vertical end of said first panel, the friction connector element has the second one of its fingers frictionally interfitted with a first gripping rib boss on said identical connector strip so the two panels are aligned in series, and in which a second friction connector element which has a body and a pair of parallel fingers identical with the fingers on the first described connector element is positioned with its fingers extending toward those of the first connector element and with each of its fingers frictionally interfitted with the second gripping rib boss on each of the two adjacent connector strips.

9. The combination of claim 8 in which a third panel is fixedly secured to the body of the first of the connector elements so as to be positioned at right angles to said first and second panels and form a closed corner with said panels.

10. The combination of claim 9 in which a fourth panel is fixedly secured to the body of the second of the connector elements so as to be aligned in series with said third panel and at right angles to said first and second panels.

11. The combination of claim 3 in which the friction bosses on the panel connector strip have forward surfaces which extend diagonally toward the planar outer surface of the base.

12. The combination of claim 11 in which each finger on the connector element has a base portion with a planar outer face that slidingly engages the planar outer surface of the connector strip base, and in which a shoulder at the outer extremity of said finger base portion extends away from the connector strip base and the outer portion of the finger is spaced from said connector strip base when assembled therewith.

13. The combination of claim 12 in which the camming portion of each finger includes a diagonal forward surface which cammingly engages the forward surface of the friction boss as the connector element is moved into engagement with the connector strip so as to spring the finger.

References Cited HENRY C. SUTHERLAND, Primary Examiner 20 J. L. RIDGILL, JR., Assistant Examiner US. Cl. X.R. 52281, 578, 497