US2911274A

US2911274A - Desk top construction

Info

Publication number: US2911274A
Application number: US579554A
Authority: US
Inventors: Karl P Grube
Original assignee: All Steel Equipment Inc
Current assignee: All Steel Equipment Inc
Priority date: 1956-04-20
Filing date: 1956-04-20
Publication date: 1959-11-03
Anticipated expiration: 1976-11-03

Description

Nov. 3, '1959 K. P. GRUBE 4 DESK TOP CONSTRUCTION Filed April 20, 1956 2 Sheets-Sheet 1' 30 J2 ,zkz/eni'or 36 [fir-Z F 672656 B W (30 "1 17a Nov. 3, 1959 K. P. GRUBE 2,911,274

DESK TOP CONSTRUCTION Filed April 20, 1956 2 Sheets-Sheet 2 fizz/6272,5297 KarZ P Grue United States Patent ment Inc., a corporation of Illinois Application April 20, 1956, Serial No. 579,554 8 Claims. (Cl. 311-106) This invention relates to a desk top employing-a sandwich type construction, and more particularly is concerned with the specific constructional features and methods employed in providinga sandwich arrangement for use as a desk top in order to achieve uniform quality desk tops over a wide range-of. sizes and shapes.

In the prior art a wide variety of desk top arrangements are known, with each arrangement emphasizing certain features of construction at the sacrifice of others. For example, such'tops', when'rnade of wood, have ordinarily been constructed in one piece or in laminar form, or, 'if made of metal, of hollow form employing internal spaced reinforcing members, and such designs emphasize one or more specific advantages, such as low cost, light weight, high strength, high rigidity, flatness, etc., while compromising other features not considered important 2,911,274 Patented Nov. 3, 1959 Other objects and. advantages of the invention will be apparent during the course of the following description.

In the accompanyingdrawings forming a part of this specification and in which like numerals are employed t'oidesignate like parts throughout the same.

Fig. 1 is a fragmentary perspective view of 'one corner of a desk and illustrates the desk top construction of this invention, the corner portion of the desk top being broken away to more clearly illustrate'the form of the several elements comprising the desk top;

Fig. 2 is an enlarged exploded view of the corner portions of :the elements of the desk top;

Fig. 3-is an enlarged fragmentary sectional view illustratingrdetails of the desk top construction and is taken on the line 3-3 of Fig. 1;

I Fig. 4 is a plan view of a desk having an oversized and irregularly contoured top;

I Fig. 5 is an enlarged fragmentary sectional view illustrating; the details of the desk top shown in Fig. 4 and is takenon the line 55 of Fig. 4;

Fig. 6 is a fragmentary perspective view of the formed angles employed inthe edge construction of Fig. 5; and

Fig. 7 is adetailed view similar to Fig. 5 but illustrating a modified form of edge construction.

Basically, the desk top consists of a filler 10 of cellular structure that preferably resembles a honey combiand which may be formed from kraftpaper impregnated with a. phenolic resin and rigidly bonded between two flat to some given application. Thus; the desk art has "not developed a universally applicable desk top construction.

Accordingly, it is the principal object of the invention to overcome the deficiencies of the prior art arrangements and provide a single desk top. construction that exhibits a maximum strength to weight ratio; that is of uniform cross sectional configurationjfthat is uniformly rigid; that provides a uniform and permanent flat upper surface; that is durable, fire-resistant and pest resistant; and that lends itself ;to low cost mass production techniques.

, Prior art desk tops involve a variety of different construction and production techniques whereasthe universal applicability, of the construction of the present invention to desk and table tops of various external configurations allows standardized production 'techniqUes to be employed. This possibility for standardization that is offered by the'invention contributes,toujadditional, savings in manufacturing costs and mininiiz l theplantequipment required. 1 v

Gen'erally speaking, the sandwich construction forthe desktop of this invention consists of top and. bottom 1 metal plates or'p an s spaced apart bya filler composed of a cellular paper arrangement whichfin cross section preferably' simulates a honey comb. Special'techr' iquesand methods are employedto makenthis construction suitable to the production of an economical high quality desk and great care is taken in bonding the plates or pans to the "fillerlin order to achieve a permanent and uniform adhesion] In the case of desks of conventional shape, thev edge construction and ornamentation may be applied according to conventional practices.- Howeveniinfthe case of desk tops of irregular shapes which present difficult manufacturing problems as respects the edge: ,construction, simplified constructions and methods have been developed that .oiferin portaut pportunities for standardization andfits accompanying economy of manufacture. h form cross sectio1ial configuration is arranged for use with'blind fasteners of sturdy construction and superior holding power I i I ing structure.

sandwich co nstructiiinljemploying a ifiller of uniwhich secure the desk top to its s'upportsh pp ng.

- sheets or pans ,of steel. Of course, other types of honey comb or cellular structures may be used. The filler whether in one piece or several may be cut to shapeby a band saw or in any other convenient way. This impregnated paper type-of filler is moisture and fire resistant and is. .not.subject to deterioration.

The topv and bottom sheets are of any suitable sheet metal material, and preferably of 22 gauge steel, and are designated 11 and 12, respectively. As indicated, a top covering 13 is bonded to the flat outer surface presented by top sheet 11. Any. conventional covering material may be employed for this top covering 13 and by way of a specific example, linoleum or Textolite are frequently used. The edges of the steel sheets are provided with vmarginal overlapping flanges, and are masked by a suitable decorative edging 14 which is fastenedin place by suitable sheet nietalscrews'le' which, preferably, also'secure-the flanges together. T

This'basic'ar'rangement fulfills the requirements of all known ,desk top applications. Invaddition, this single arrangement offers vastly superior physical characteristics and is capable vof replacing all of the many and varied desktop constructions presently employed. The resultant standardization made possible by the present invention oifers important economies in the desk manufacturing art v Among the many highly advantageous physical characteristics thefact that the present desk top construction'exhibitsa substantially higher strength toweight ratio than any of the priorart'airrangements. The desk top of the inventionis approximately sixteenv times.as rigid as" a, conventional steel desktop of the same weight. The weight of a honey comb sandwich. type desktop 6 O" x 30") is only 48 pounds whereas the weight of a conventional steel reinforced desk top of the same dimension is.about 60 pounds. Furthermore, a honey comb conventi'onal.,,s'teel reinforced .topover the same span;

Not only areidesk. topsen bodying the light weight honey comb sandwich. type construction easier to I handle, Y but they also effect va considerable savings in -freight and 'i, i V I Another feature which renders this construction pan ticularly effective inthe production of desk tops, is the fact that its cross section is everywhere uniform such that no special reinforcing problems arise in the production of irregularly shaped tops. Similarly, all areas of the desk top are equally well adapted for attachment to the supporting pedestal. This uniform construction results in a highly desirable inherent rigidity for the top structure which is so important in oversize desktops which have become increasingly popular in recent years. tion, this inherent rigidity prevents machines supported on the desk top from jumpng or moving about on the top during operation, as so often happens with conventional steel reinforced tops.

Probably the most important single requirement of a desk top is that it be flat and the honey comb sandwich type construction is particularly eflicacious in achieving this goal. Apart from the obvious desirability of providing a flat writing surface, the absolute flatness of the honey comb construction improves the bonding between the top covering 13 and the upper surface of the top pan 11. In this connection it should be noted that the rigidity and flatness of the honey comb top renders this top readily adaptable to the use of a squeeze roll press for applying the top covering material to the top pan. It has been observed that conventional steel reinforced tops eventually develop waves or high spots directly over the reinforcing members, but this objectionable characteristic can never arise due to the more uniform supporting action built into the present arrangement.

The desk tops of the present invention are constructed according to the following procedures:

A. Adhesive is applied to the contacting surfaces of the paper honey comb and the top and bottom pans;

Preferably a roller coater is employed for applying adhesive to the honey comb structure while the adhesive may be sprayed on to the metal pans.

The adhesive preferably employed is of the class called synthetic rubber adhesive (solvent). The adhesive consists of a mixture of neoprene and resin dissolved in a ketone solvent such as acetone, methyl ethyl ketone, etc. This combination produces high initial tack and strength after the solvent has been driven off. The resin then affords much higher strength upon aging while the neoprene lends the characteristic of toughness Without embrittlement.

B. In production of limited quantities these parts may then be hung up overnight to allow the adhesive to dry. However, the arrangement is readily adapted to mass production techniques and in such an instance an infra red drying oven is employed to reduce the adhesive drying time to a matter of minutes.

C. The principal parts of the desk top are then assembled, preferably, in inverted relationship. Thus, the requisite number of honey comb pieces are properly located on top of the inner surface of the' top pan and the bottom pan is then applied to complete the sandwich. Of course a single appropriately contoured honey comb piece may be used if desired.

In addirectangular shape is shown, it will be seen that the top and bottom steel pans may be formed from steel sheets of appropriate shape. The straight sided sheet metal pans are formed with arcuate cutouts 20 at their corners. In forming the rounded corners on the top and bottom pans, the straight sides are first bent down to form right angle flanges and then suitable drawing dies are employed to form the arcuate corner flanges 21. The flange portions 22 of the top pan are formed with a rib or bead 23 so that when the parts are asesmbled, the flange portions of the top pan nest within the flange portions 24 of the bottom pan with the upper edges of the bottom flanges closelyadjacent to the bead 23 (see Fig. 3).

The manner of arranging and forming the flanges has only been briefly described herein but is generally similar to that shown and described in United States Patent No. 2,646,327 to F. A. Saaf.

After the sandwich has been completely assembled, as described, with the parts bonded together and a top covering of linoleum or other suitable material applied, the edge molding 14 is secured to the flanges. For this purpose the flange portions are formed with registering apertures 26 at spaced points about the periphery of the desk top and the molding is secured through these apertures.

The molding consists of a channel shaped retaining member 27 which preferably is a flexible strip of extruded aluminum adapted for mounting and retaining an ornamental covering strip 28 which may be of extruded or molded pliant material such as a vinyl plastic. The screws 15 engage in the apertures 26 to fasten the retaining member 27 to the overlapping

flanges

22 and 24, and then the ornamental strip 28 is fitted into place and it serves to mask the fastening screws.

The present invention employs a highly effective arrangement for attaching the desk top to the supporting structure 30 as shown in Fig. 3 wherein a headed fastener 31 is inserted in a countersunk opening 32 in the bottom pan and is mounted with its head 33 in flush relation with the bottom pan 12. These punched and embossed openings 32 for the fasteners 31 are formed when the pan is flat. The fastener 31 is applied to the desk top assembly by a special tool (not shown) which exerts compression between the head 33 and a threaded bore 34 D. In the production of limited quantities of desk tops the assemblage is heated in a steam heated hydraulic platen press for approximately five minutes. In a mass production arrangement, this operation may be accomplished by means of an infra red oven for heating andla squeeze pressure roll machine for bondin'g'the parts together under pressure.

B. After the bonding operation the tops. are stacked on a flat surface and suitably covered'for assuring uniform cooling. After they have been cooled, they are ready for the final assembly operations of applying the top covering which as previously pointed out may also be accomplishedby means of a squeeze roll press and finally the edging is securedto the assembled top.

Depending upon the configuration of the desk top,

slightly different edge constructions are employed, Re-

ferring now to Figs. 1-3, wherein .a desk top. of generally 'to desk tops of conventional shape.

structure.

formed in the fastener to upset the shank of the fastener and form a retaining shoulder 35. Thus the bottom pan 12 is gripped between the head 33 and shoulder 35 of the fastener. The threaded bore 34 subsequently receives anattaching screw 36 that is passed through the supporting structure 30 and held therein by a suitable washer 37. While the specific fastener shown herein is not new per se, its use in the disclosed manner in connection with the desk top construction of the present invention offers unique advantages. It will be apparent that the honey comb structure yields as required in response to the concentrated forces developed in the region of the countersunk openings, without interfering with the firm bonding of the filler 10 to the top and bottom pans 11 and 12.

The arrangement allows a blind fastener to be connected with equal facility at any desired point on the bottom pan and this is a particularly important factor in the case of desks having tops of unusual configuration. When spaced reinforcing members of the prior art are employed in a desk top construction, care must be given to their location in order to insure that the desk top may be attached to the supporting structure in proper relationship.

The flanged edge construction of Figs. 1 3 is well suited However, attractively contoured desk top configurations, such as shown 'at 38 in Fig. 4,'involving a continuously curving edge surface have become increasingly popular and the problem of economically producing such configurations is for the first time achieved by means of the honey comb In addition, the honey comb sandwich type arrangement due to its uniform rigidity and high strength permits such arrangements to overhang the supporting structure by appreciable amounts without fear of damage when the overhanging portion is used to support people or office machines. The basic arrangement and construction of the sandwich is similar to; that outlined'hereinbefore, however, special techniques are employedfo'rthe edge construction.

A preferred form of edge construction is shown in Fig. 5 wherein it will be seen that the top and

bottom members

11a and 12a, respectively, are perfectly fiat and have no integral depending flanges. Thus, theymay readily be die cut into any desired shape or size. 'In order to provide a curved edge construction, formed angles are preferably spot welded to the top and bottom sheets. As indicated in Fig. 6, the horizontally disposed

flanges

40 and 41 of these angles are formed with a plurality of notches 42 in order to permit the angle to be bent to any desired curved shape. After forming, these horizontal flanges are then secured to the marginal edges of the top and bottom sheets as indicated in Fig. 5. Again the arrangement is such that the top sheet with its-ledge flanges nests within the edge flanges of the bottom sheet and the flanges are formed .with. registering apertures, either before or after welding, that'receive the mounting screws 15 for the retaining strip. I

It will be apparent that this construction is applicable to desk tops of any desired contour. Here again, a headed blind fastener 31 having an upsettable portion forming a gripping shoulder 35 is employed for attaching the top to its supporting structure 30.

In lieu of employing continuous angles, a plurality of appropriately spaced individual brackets may be secured about the periphery of the

sheet metal members

11a and 12a to receive the edge molding. In this connection, it should be noted that it is not impractical to provide'only one of the pans with depending flanges for mounting the edge molding since the adhesive together with the edge construction can be depended upon" to maintain the sandwich unitary.

An alternative arrangement for providing edges on curved desk tops is illustrated in Fig. 7 wherein the top and bottom pans 11b and 12b are shown as including integral rolled over

flange portions

44 and 45, respectively. Angle edging machines for this purpose are well known in the art and are readily able to form right angle flanges on plates having curved marginal areas. One such hand operated angle edger is known as Model F produced by the Maplewood Manufacturing Company of Chicago, Illinois.

In the construction of Fig. 7 the top and bottom sheets are flanged prior to the assembly of the sandwich and, also priorto their assembly, a continuous flexible strip 46 is inserted between the marginal edges of the top and bottom flanges. This strip is of a greater height than the vertical spacing between the opposed flanges and'as the molding strip 27 is applied suitableholes are drilled through the

strips

27 and 46 to receive self tapping screws 15 to holdthemolding or retaining strip 27 in place.

Thus it will be seen that the objects of the invention have been accomplished in that the standardized honey comb filler structure provides high strength, light weight, economical desk tops regardless of the configuration desired. In addition, the tops may readily be provided with a decorative edging and they accommodate sturdy fasteners for facilitating their attachment to the supporting structure, as shown in Fig. 4.

g'inal flange, a composite cellular filler structure interposed between said pans with bonding material securing the filler structure to the pans, a layer of desk top material overlying the exterior of the upper one of said pans with bonding material adhering substantially the entire expanse of said layerto said upper pan, and a flexible molding overlying and masking themar'ginal flange and including attachment means engaging said flange to secure said flexible molding in place. I i

V 2. In combination, a supporting structure including a substantially flat surface having spaced openings, a desk top including top and bottom flat sheet metal pans and an interposed compositecellular filler structure secured thereto by bonding material, a layer of desk top material overlying the exterior of said upper pan with bonding material adhering substantially the entire expanse of said layer to said upper pan, said bottom metal .pan having spaced inwardly embossed portions formed with openings arranged for registration with the openings in said flat plate, said filler structure being yieldable in response to the localized pressures in the region of said embossed portions, mounting'fasteners disposed in the openings in the bottom panand each including a head and deformable shoulde'r'means gripping the embossed portions surrounding the openings in the bottom pan with the head lying flushwith the outer surface of:the bottom pan, said fasteners having threaded bores, and threaded attachment means passing through the openings in the flat surface "of said supporting structure and said bottom pan and engaged between said flat surface and the threaded bores of said fasteners to secure the desk top to the supporting structure.

3. A desk top comprising a pair of flat sheet metal pans "and an interposed composite cellular filler structure secured thereto by bonding material, each pan including inturned marginal flanges arranged in overlapping nesting relationship and formed with registering openings, a layer of desk top material overlying the exteriorof the upper oneof said pans with bonding material adhering substantially the entire expanse of said layer to said upper pan, and a flexible molding overlying and masking the marginal flanges and including attachment means engaging the openings in said flanges to secure said flexible molding in place.

4. A desk top comprising a pair of flat sheet metal pans, each including inturned marginal flanges, a composite cellular filler structure and a surrounding attachment strip interposed between said pans and spacing said flanges apart a distance less than the width of the attachment strip, bonding material securing said filler structure to said pans, a layer of desk top material overlying the exterior of the upper one of said pans with bonding ma- It should be understood that the description of illus- I trative forms of the invention are for the purpose of complying with Section 112, Title 35 of the United States Code and that the appended claims should beconstrued as broadly as the prior art will permit.

I claim: I

1. A desk top comprising a pair of. flat sheet. metal pans, at least one of said pans includingan inturned marterial adhering substantially the entire expanse of said layer to said upper pan, and a flexible molding overlying and masking the marginal flanges and attachment strip and including attachment means engaging said strip such that said strip abuts against said flanges and holds said flexible molding in place. i

5. A desk top comprising a pair of sheet metal pans each including inturned marginal flanges, a reinforcing structure and a surrounding strip interposed between said pans'and spacing said pans apart a distance less than the width of the attachment strip, means for securing said reinforcing structure to said pans, and a flexible molding overlying and masking the marginal flanges and attachment strip and including attachment means passing between said flanges and engaging said strip such that said strip abuts against said flanges and holds said flexible molding in-place.

6. A contoureddesk top of irregular shape comprising a pair of fiat sheet metal pans and an interposed composite cellular structure secured thereto by bonding material, a layer of desk top material overlying the exterior of the upper one of said pans with bonding material ad- 7 said upper pan, each pan having inturned marginal flanges comprising formed angles secured to the pans proper and arrangedin overlapping nesting relationship, said overlapping flanges having registering openings, and

a flexible molding overlying and masking the flanges and including attachment means engaging the openings in said flanges to secure said flexible molding in place.

7. The method of constructing a desk top of any desired contour which comprises forming top and bottom metal plates of the desired contour, providing laterally extending marginal flange means on at least one of said plates, shaping a composite cellular filler structure substantially coextensive with said plates to the desired contour, bonding the top and bottom plates to the filler structure to provide a desk top having a uniform cross sectional construction of the desired contour, shaping a layer of desk top material substantially coextensive with the upper plate, bonding substantially the entire expanse of said layer to the exterior of said upper plate, and securing a flexible edging at spaced points to the marginal flange means to mask'the same.

8. The method of construcing a desk top of any desired contour which comprises forming top and bottom metal pans of the desired contour and inwardly embossing and aperturing the bottom pan at spaced points, providing inwardly extending marginalflange means on at least one of said pans, shaping acomposite cellular filler structure substantially coextensive with said pans to the desired contour, pressure bonding the top and bottom pans to the filler structure such that the filler yields in response to the localized pressures'in the region of the embossed points and said pans are disposed'inparallel relation, attaching headed fasteners to said embossed portions with the heads thereof in flush'relation with said bottom pan, shaping a layer of desk top material substantially coextensive with the upper pan, pressure bonding substantially the entire expanse of said layer to the exterior of said upper pan,and securing a flexible edging at spaced points to the marginal flange means to mask the same.

References Cited in the file of this patent UNITED STATES PATENTS 1,779,426 Frederick Oct. 26, 1930 1,873,932 Hunter." Aug. 23, 1932 1,876,330 Loetscher Sept. 6, 1932 2,269,331 Arborn Ian. 6, 1942 2,461,823v Jones Feb. 15, 1949 2,477,852. Bacon Aug. 2, 1949 2,479,342 Gibbons Aug. 16,1949 2,609,068' Pajak Sept. 2, 1952 2,646,327 Saaf July 21, 1953 2,739,640 Brinker March 27, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,911,274 November 3, 1959 Karl P. Grube It is hereby certified that error appears in the printed specification of the above numbered patent requiring correct-ion and that the said Letters Patent should readas corrected below.

Column 6, 1111620, for "plate" read surface column '7, line" 22, for "construcing" read constructing Signed and sealed this 26th day of April 1960.

(SEAL) Attest:

KARL H. AXLINET Attesting ()flicer ROBERT C. WATSON Commissioner of Patents