Lattice assembly, e.g. for mosaic tiles, electrical circuit elements and display systems
[ 51 Apr. 15, 1975 LATTICE ASSEMBLY, E.G. FOR MOSAIC TILES, ELECTRICAL CIRCUIT ELEMENTS AND DISPLAY SYSTEMS Primary Examiner-Ernest R. Purser Assistant Examiner-Carl D. Friedman Attorney, Agent, or Firm-Karl E. Ross; Herbert Dubno [57] ABSTRACT A latticework is formed from a plurality of cell-forming elements connected by bolts to anchors. Each element has at least two connection portions each formed with at least one lateral face abuttable with a similar face of another like element. The anchor is formed with a threaded hole having a counterbore into which a tooth or tab formed on each of a pair of connection portions engage when a bolt is screwed into the hole and its head bears against the respective connection portions. Tiles which may carry a schematic drawing of the circuitry they cover or which may carry circuit elements are fitted over each cell of the lattice.  
 7 Claims, 8 Drawing Figures LATTICE ASSEMBLY, E.G. FOR MOSAIC TILES. ELECTRIC AL CIRCUIT ELEMENTS AND DISPLAY SYSTEMS FIELD OF THE INVENTION The present invention relates to a construction element for forming a covered latticework. More specifically this invention concerns a lattice assembly for a control panel for electrical circuitry.  
 BACKGROUND OF THE INVENTION Control panels often are formed on lattice work with cover plates or tiles covering each opening in the lattice. These tiles may carry indicia indicating the circuitry they cover or can act as mounts for switches. pilot lights, meters, and the like. It is also known to draw an overall schematic of the circuitry over a whole wall of such tiles with the specific circuit elements, junctions, and the like shown on each tile being accessible by removal of that particular tile. Such a control panel is used often in high-power electrical generation plants where a schematic traced along the surface of the tiles is interrupted by meters indicating the current or voltage at a particular diagrammatically illustrated point and by switches and similar controls to allow adjustment of the installation. In this manner it is possible to have a very clear view of exactly what is happening in the installation, while it is possible to control particular parameters simply by reference to the circuit drawn on the panel.  
  The lattice elements can be either generally starshaped. i.e. having a plurality of arms extending from a common center, or closed, i.e. constituting a continuous usually polygonal frame. The ends of the arms or the corners of the frames are constituted as connection portions which are secured to anchors usually by means of bolts. One such bolt is frequently passed through holes formed in overlapping connection portions of several elements to secure all of these elements to a single anchor. To this end some of the connection portions are formed to lie offset to the plane of the generally planar lattice elements. In this type of arrangement it is necessary to completely withdraw the fastener bolt to remove or add a single element to the latticework array.  
  It is also known to secure the connection portion simply under the edges of the fastener bolt, but such an arrangement is frequently inadequately strong. Numerous solutions to this problem have been suggested. but  
 none offer adequate rigidity in the finished installation as well as low cost.  
 OBJECTS OF THE INVENTION It is an object of the present invention to provide an improved lattice assembly of the above-described general type.  
  Another object is the provision of such a latticework which is inexpensive and simple to manufacture and which can be assembled in an easy manner.  
  Yet another object is to provide a lattice assembly which can be adapted to a plurality of shapes.  
 SUMMARY OF THE INVENTION These objects are attained according to the present invention by a lattice assembly having a plurality of rigid lattice elements each having at least two connection portions each formed with at least one lateral face adapted to abut a similar face of a similar portion on another such element. Anchors are provided which are formed with a threaded hole itself having a counterbore. Each lattice element is formed at the edge of its connection portion with a tab which projects from the plane of the element parallel to the axis of the counterbore and this tab is engaged in the counterbore. The fastener bolt is screwed down into the hole in the anchor so that its head lies over the connection portions ofall the lattice elements whose tabs are engaged in the counterbore.  
  According to another feature of the invention each connection portion has two such lateral faces which lie in planes that intersect at the central axis of the bolt. Between these faces the connection portion is formed with a circularly arcuate surface whose center of curvature also lies on this axis. The tab lies along this arcuate edge and therefore has the shape of a segment of a cy lindrical annulus. The lattice elements according to this invention are stamped out of heavy sheet metal and the tabs are also formed in the stamping operation.  
  In accordance with yet another feature of the invention the bolt has a shank which is unthreaded adjacent its head in the region engaged against the curved edge of the connecting portion. In such an arrangement it is possible to add, remove. or replace a lattice element simply by screwing out the bolt a distance sufficient to free the tab from the counterbore or to allow another tab to be fit in the counterbore.  
  With such an arrangement the lattice elements are securely held to the anchors. Forces orthogonal to the plane of. the elements, or to a plane tangential to slightly arcuate or dished elements, are easily taken up by the bolt and the anchor in compression and tension. Forces toward and away from the bolt are taken up either by pressing of the edge against the bolt or by the tab against the inside of the counterbore.  
 DESCRIPTION OF THE DRAWING The above and other objects. features and advantages will become apparent from the following description, reference being made to the accompanying drawing in which:  
  FIG. 1 is a front elevational view of a first embodiment of the present invention;  
 FIG. 2 is a side elevational view of the first embodi ment;  
  FIG. 3 is a large-scale view of the detail indicated by arrow III in FIG. 1;  
  FIG. 4 is a section taken along line IV IV of FIG.  
  FIGS. 5 and 6 are views similar to FIGS. 1 and 2, respectively, showing a second embodiment of the invention; and  
  FIGS. 7 and 8 are views similar to FIGS. 3 and 4, respectively, showing a third embodiment of the present invention.  
 SPECIFIC DESCRIPTION As seen in FIGS. 1 and 2 a latticework 1 is formed of a plurality of cruciform elements 3 forming cells covered by mosaic face plates 2 for use as a control panel. Each cross 3 has four arms 10 clamped with three other such arms to one end of a spacer or anchor 5 by a screw 7. The other end of the spacer 5 is similarly fastened to four crosses. In this manner a two-level lattice is formed which is rigid and can stand with the planar elements 3 vertical. The crosses 3 on one side at least of the lattice are provided at their very centers with spring clips 11 having four clips adapted to snap into and hold the tiles 2 in place.  
  FlGS. 2 and 3 show how each end 4 of each arm 11 is formed as a connecting portion for attachment of that element to one of the spacers 5. The spacers 5 are cylindrical aluminum bars whose outlines are shown in dot-dash lines in FIG. 3.  
  Each end 4 has a pair of faces 16 lying at 90 to each other and at 45 to the longitudinal axis of the respective arm 10. A small round cutout is formed at the very point of each end 4 to accomodate the fastening bolt 7. The surfaces of the faces 16 and of the cutout 15 extend at right angles to the plane of the respective element 3.  
  The screw 7 has a threaded shank 17 received in a threaded bore 8 in the spacer 5 and a head 9 overhanging the ends 4 and engaging them with its bottom surface. Between the threaded region l7 and the head 9 the bolt 7 is formed with a short unthreaded region 14 having a diameter (1 and a length I.  
  The bore, 8 is formed with a counterbore 12 having a diameter D substantially larger than the diameter (1 and concentric to the axis A of the bolt 9. In addition each connection portion 4 is formed along the circularly arcuate edge 15, which is centered on the axis A in the assembled condition shown in FIG. 3, with a short projecting tab 13 of constant and rectangular cross section which has a width w which is slightly less than the difference between diameters D and (I. In this manner the tab 13 fits in the counterbore 12. The lattice elements 3 are stamped out of sheet metal having a thickness T and the tabs 13 are formed simultancously during the stamping operation so that a step is also formed in the face of the element opposite to that of the tabs 13. The length I is larger than the thickness T and the height ll of the tabs 13 so that the connection portions 4 do not bear against the threads of the shank region 17 at all in the assembled latticework 1.  
  FIG. 1 shows at R the distance between centers of the elements 3. This distance is equal to the distance A from the center of each star-shaped element 3 to the inside edge of the tab or tooth 13 plus D/2. or equal to the distance a from the elements center to the outside edge 15 plus 11/2. In this manner when tension is applied to an arm l0 its tab 13 will engage against the inside of the counterbore l2 and catch, and when the arm is placed under compression its edge 15 will press against the shank region 14. A very stiff arrangement is formed in this manner. one capable of withstanding relatively great stresses.  
  FIG. 1 also shows how a meter M can be mounted in a tile 1 with a schematic depiction S of its connections being provided on the neighboring tiles. in addition a circuit subassembly or rack C having a switch SW and a pilot light PL can be fitted into a cell of the lattice, a correspondingly drilled-out tile would be fitted over the cell subsequently.  
  FlGS. 5 and 6 show an arrangement wherein rectangularly annular elements 22 are provided. each having four sides 22a and four corners 27. Bolts 24 identical to the bolts 9 hold the elements 22 down against spacers identical to those of FIGS. 1 4. The corners 27 constitute connecting regions and have faces 30 which lie in surface contact with the faces 30 of the adjacent element 22. In addition each spacer only has two diago- LII nally opposite tongues 29 on its end surface which engage through the respective eorners 27 to prevent them from canting. Tiles 2] are snapped over the heads of the bolts 24.  
  It should be noted that instead of square annular elements 22 triangular ones also could be employed.  
  FIG. 7 shows a plurality of elements 62 which have three arms 62a 62c extending at to one another so that they form a honeycomb lattice. In all other respects these elements 62 are identical with the elements hitherto described. lt should be clear that along the same lines a variety of geometric shapes can be formed. and that elements of different configuration can be combined to provide a multiplicity oflattice variations.  
  In FIG. 8 elements 82 and 102 are shown separated by spacers 93. These elements are arcuate and the elements 102 are somewhat smaller than the elements 82 to permit fabrication of a lattice that is curved in one or two planes. depending on whether each element is simply curved or dished. It should be clear that the curvature and the length of the spacers 93 determines the relative sizes of the elements 82 and I02.  
 I claim:  
 1. A lattice assembly comprising:  
 a plurality of generally planar rigid cell-forming lattice elements each having a connection portion formed with at least one arc-segmental tab projecting laterally from the plane of the respective element. said connection portions meeting at corners of the cells:  
 a plurality of anchors at said corners and each formed with a threaded hole having a counterbore. said tabs at each corner being engaged in the respective counterbore; and  
 a plurality of fastener bolts each having a threaded shank received in said hole and a head engaging and overlying the respective connection portions of the elements having tabs in the respective counterbore to clamp said respective connection portions against said anchor. said tabs lying between a surface of said shank and a wall of the respective counterbore.  
  2. The assembly defined in claim 1. further comprising a plurality of mosaic titles of polygonal outline each having corners releasably engaging the heads of respective bolts.  
  3. The assembly defined in claim 2 wherein said bolts have a shank formed adjacent the bolt head with an unthreaded region, said connection portions each being formed with a curved edge snugly engageable against a respective unthreaded region.  
  4. The assembly defined in claim 3 wherein each of said connection portions is formed to each side of said curved edge with a lateral face adapted to abut a similar face of a similar portion of another such element. said edge being circularly arcuate.  
  5. The assembly defined in claim 4 wherein said hole and said counterbore are cylindrical and coaxial. said tab having the shape of a segment of a cylindrical annulus.  
  6. The assembly defined in claim 5 wherein said elements are formed with a plurality of arms extending from a common center and each having at its free end one such connection portion.  
  7. The assembly defined in claim 5 wherein said elements are annular and have corners formed with said connection portions.