US3035446A

US3035446A - Instrument panel assemblies

Info

Publication number: US3035446A
Application number: US810906A
Authority: US
Inventors: Raymond W Ross
Original assignee: Leeds and Northrup Co
Current assignee: Leeds and Northrup Co
Priority date: 1959-05-04
Filing date: 1959-05-04
Publication date: 1962-05-22
Anticipated expiration: 1979-05-22

Description

May 22, 1962 R. W. ROSS INSTRUMENT PANEL ASSEMBLIES Filed May 4. 1959 4 Sheets-Sheet 1 Fig. l

y 1962 R. w. R088 3,035,446

INSTRUMENT PANEL ASSEMBLIES Filed May 4, 1959 4 Sheets-Sheet 2 F g. J: I I I I I I I I MN-NAM IIIIIIIII.

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May 22, 1962 R. W. ROSS INSTRUMENT PANEL ASSEMBLIES Filed May 4, 1959 one 4 Sheets-Sheet 3 May 22, 1962 R. w. R058 INSTRUMENT PANEL ASSEMBLIES Filed May 4, 1959 4 Sheets-Sheet 4 4a 60 q I, 20c A:.: s2 l9f- I99 I96 g -20. l8 p, 1 B 20 l6f 6g l8f 3,035,446 INSTRUMENT PANEL ASSEMBLIES Raymond W. Ross, Cheltenham, Pa., assignor to Leeds and Northrup Company, Philadelphia, Pa, a corporation of Pennsylvania Filed May 4, 1959, Ser. No. 810,906 11 Claims. (Cl. 73-432) This invention relates to measuring instrument panel structures and has for an object the provision of a panel assembly for receiving flush-mounted instruments and accessories of widely differing dimensions and which has structural provisions avoiding the need to cut openings in solid panel structures, thereby to eliminate waste of material while at the same time providing a structure which is strong, rigid, and unusually attractive in appearance and one which may at any time be enlarged without destroying its attractive appearance.

For many years measuring and controlling instruments have been supported upon solid panels having cut-outs to receive the various instruments. Such panels have been made of a variety of materials including slate and steel, which materials, in general, have required relatively expensive operations to provide the necessary cutouts, and much material has been wasted.

In carrying out the present invention, there is provided a panel assembly for instruments for measuring and controlling magnitudes of conditions in which the width of the openings for the instruments correspond with the sum of the widths of a selected number of panel members and in which the heights of said openings are determined by the lengths of the panel sections above and below the location of a particular opening. The panel members are of differing widths and are so disposed in the panel assembly as to provide in that assembly openings of diflerent widths, each selected to accommodate an instrument of the corresponding width. In this manner, there are avoided the operations incident to cutting from a solid panel openings to receive instruments of variable dimension. Not only is there achieved a saving in labor and materials, but there is also achieved a construction highly versatile in its ability to accommodate with a minimum of operations instruments of widely differing dimensions.

Further in accordance with the present invention, the several panel members are formed of extruded material, such as aluminum. The several panel members, including those of variable width, have on their front faces vertically extending flutes and ribs disposed in symmetrical array. By means of mechanical interlocking structure, such as tongues and grooves, the panel members interconnect one with the other to maintain across a plurality of panel members the symmetrical disposition of the flutes and ribs. In this manner, there is provided a panel assembly uniform in appearance notwithstanding the presence of individual panel members of variable width. The extruded panel members respectively include rearwardly extendingribs adjacent edge portions thereof to provide the requisite rigidity for each panel member. Because of the rearwardly extending ribs, the panel members may be of relatively thin cross-section. Each extruded panel member additionally includes a pair of spaced parallel ribs having a series of opposed -serrations for receiving therebetween the threads of fastening bolts or screws. Thus, cap screws may be located as desired lengthwise of the plurality of panel members to secure them to additional supporting structure and bracing members.

Further in accordance with the invention, the extruded end-panel members include not only the serrated screwreceiving ribs, but also larger rearwardly extending ribs providing rigid column supports for the panel together with threaded elements adjustable relative to the column members for fastening thereto additional supporting structure for the panel.

It is also an object of the invention to provide a lowcost, attractive, and durable means for applying to a panel structure graphic representations of a process.

For further objects and advantages of the invention, and for a more detailed discussion of the manner in which it may be utilized in panel assemblies, references is to be had to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an isometric view of a panel assembly embodying the invention;

FIG. 2 is an enlarged sectional view taken on the line 2--2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken on the line 3--3 of FIG. 1;

FIG. 3A is an end view of a modification illustrating a combined trim strip and channel cross-brace;

FIG. 4 is an enlarged fractional View of a portion of the panel assembly of FIG. 1 and to which there have been added panel-marking members;

FIG. 5 is a sectional view of a modified form of rib and flute configuration with marking members;

FIG. 6 is an isometric view of a panel-marking member;

FIG. 6A is an end view of a modified form of marking strip;

FIG. 7 is a rear view of a portion of the panel assembly of FIG. 1; and

FIGS. 8, 9 and 10 are enlarged cross-sectional views which together have been taken along the

section line

8, 9 and 10 of FIG. 1.

Referring now to FIG. 1, there has been illustrated a panel assembly embodying the invention and comprising two panel sections 10a and 10b. In panel section lllb there are illustrated openings or windows to receive instruments for the measurement and/or control of variable conditions. Such instruments may widely differ in width and height. For example, the recording and measuring instrument 31 of panel 10a requires an opening,

such as opening 11, much larger than the opening 12 of a size to accommodate a control-instrument 32. The instrument 33 is of a still different size and requires an opening 13 diflering from openings 11 and 12.

In accordance with the present invention, it is to be noted that the

openings

11, 12 and 13 have been provided by the simple expedient of cutting panel members to predetermined lengths. A number of the panel members 142ti are of differing widths and in the regions of the openings they have been assembled so that the sum of the widths of a selected number of panels will be equal to the desired width dimension for the respective openings. The

end panel members

14 and 20 of sections 10a and 10b, FIGS. 1,8 and 10, are continuous from top to bottom. The panel member 15, FIGS. 1

and 10, comprises a lower portion 1511, FIG. 1, having a length such that the top thereof terminates at the bottom of the opening 11. The upper portion 15b has a length such that its lower end terminates at the upper edge of opening 11. Similarly, panel members 1618, FIGS. 1, 8-10, are made up of lower portions 16a--18a, FIG. 1, intermediate portions 16b18b, 16c18c and upper portions 16d18d. This is true with respect to panel members 17a-17b. The panel member 19, FIGS. 1 and 8, has a lower portion 1911, FIG. 1, and an upper portion 1917. It is to be understood that the several panel members are all extruded, as from aluminum, and all are delivered with predetermined lengths. Thus, to provide the individual portions of a panel member, such for example, as panel member 17, it is only necessary to cut from a single length of stock the

several portions

17a, 17b, 17c and 17d. Thus, there is avoided all loss of stock material, notwithstanding the provision of the three windows illustrated in the embodiment of FIG. 1.

As shown in FIGS. 1, 8, 9 and 10, the

panel members

15 and 19 have equal widths of 3%". The

panel members

16 and 18 have equal widths of 2%", while the panel member 17 has a width of Thus with the tongues set in the cooperating grooves, the opening 11 has a width of 16 /3, adequate to accommodate the width of instrument 31. Opening 12 has a width of the same as the width of opening 13. Instrument 33 requires a window 13 of greater height than window 12 and as will be seen, this is provided by reducing the lengths of the lower portions 16a, 17a and 18a by appropriate amounts. In the embodiment of the invention illustrated in FIG. 1, the

openings

11, 12 and 13 had heights respectively of 18%;", 6 4 and 10%;".

The panel assembly 10 has a top trim strip 21 formed by an angle-member, the front portion of which, FIG. 2, extends along the front of the panel and the top portion of which covers the top of the panel. The trim strip or angle-member 21 is secured in place as by a plurality of bolts and nuts 22 which extend through openings in the top portion of angle-member 21 and through mating openings in a channel-shaped brace or cross-member 23 having inturned ends 2311 and 23b. The upper portion 18d of panel member 18 is secured to the panel member 23 by a machine screw 24. The manner in which the screws 24 secure panel portions in place will be readily understood in connection with the description of the sectional views of FIGS. 8 to 10.

A trim strip 25 formed by an angle-member is provided at the lower end of the panel assembly 10 and is fastened to a channel member 26, FIG. 3, also having inturned ends. These inturned ends are arranged to nest within grooves in a nut 27 which receives a cap screw 28 to secure together an angularly-shaped corner plate 29 and a 90 angle bracket 30 through which may extend a screw 34 to anchor the panel assembly to the floor. Braces 35 are secured to the back of the panel and to the floor, one such brace appearing in FIG. 1 and two of them appearing in FIG. 7.

Referring now to FIG. 3A, it will be observed that the channel 26 and the trim strip 25 of FIG. 3 have been combined into a single extruded structure including the channel 26a and the forward trim strip 25a. The structure of FIG. 3A may be utilized for the top trim panel and channel structure as shown in FIG. 2. By utilizing the structure of FIG. 3A, the upper and

lower channels

23 and 52 of FIG. 7 may extend the full width of the panel section 10b, and if desired, it may extend across all panel sections, that is to say, across both panel sections 10a and 10b of FIG. 1. Thus, the extruded trim and channel section of FIG. 3A may in some instances be preferred in that it will simplify the assembly of the several parts and will provide added rigidity.

In order to provide a symmetrical and pleasing pattern for the front of the panel assembly, the panel members have vertically extending flutes and ribs best shown in FIG. 4 and in FIGS. 8-10. Thus as viewed in FIG. 4, the flutes and ribs render indistinguishable the meeting lines of the several panel members. The flutes and ribs have additional functions. Thus, the recording and indicating instrument 31 may have in association therewith a graphic representation of the apparatus from which measurements are being made and recorded by the instrument 31. As shown in FIG. 4, the instrument 31 is located in associaton with a representation of a vessel 36 from which there extends a flow line 37 which on the panel as a whole leads to other associated apparatus (not shown). An additional flow line 38 extends from the representation of vessel 36 to other associated apparatus not shown in FIG. 4.

For an electrical measuring circuit or a circuit for controlling the magnitude of the condition under measurement, there appears representation of an electrical line 39 extending from the instrument itself to another portion of the panel assembly. While representations on panels of instruments, lines and circuits have heretofore been utilized, and are commonly referred to as Graphic Panels, the flutes and ribs of the panel assembly of the present invention have been utilized for the achievement of great flexibility in the kind of flow diagrams which may be utilized. Thus, by providing channel-shaped marking members 40, such as shown in FIG. 6, made of a plastic material and distinctively colored, graphic representations may be added to, changed, and otherwise utilized to provide the maximum information on the face of the panel as to the nature and character of the measurements and controlling operations performed by the instruments on the panel assembly.

While synthetic resins and plastic materials of the type which may be readily extruded and available in distinctive colors are to be preferred, it is to be understood that channel members of other materials and of shape similar to the one illustrated in FIG. 6 may be utilized with or without the inturned ends 40a and 4012. These inturned ends, as illustrated in FIG. 5, are preferably utilized when the flutes have dovetail shapes, as shown in FIG. 5. Two adjacent

channel marking elements

41 and 42 have their side portions pressed into a flute 43 of a panel member 44 with their opposite edge portions pressed into

flutes

45 and 46. It is in this manner, as shown in FIG. 4, that graphic representations may be placed on a panel with the measuring instruments. By utilizing channel markers in spaced relation spanning alternate ribs as illustrated for the line 39, it will be seen that a wide variety of combinations of colors in solid and broken-line array may be utilized for symbolic representations of complicated systems. Since the channel markers are made of a synthetic, resilient plastic, such as polyvinyl chloride or polyethylene, they are readily cut to length and shape by ordinary shears, scissors or a sharp knife. As shown in FIG. 6A, the channel markers may embrace more than a single rib, and such channel markers may be die-cut into more complicated designs representative of valves and the like. As shown in FIG. 6A, there extend from the front surface 70 three

legs

70a, 70b and 700.

Legs

70a and 70c correspond with those illustrated in FIG. 6. The intermediate leg 70b is of double thickness and has a V- shaped cut-out (formed during the extruding process) to make easier the insertion of the central leg in one of the flutes and with retainment of the advantages of the locking-beads 7012 provided on opposite corners of the central leg 70b.

Referring now to FIG. 7, there appears a rear view of the panel section 10b and a portion of the panel section 10a. Across the top of panel section 10b there extends the channel 23. This channel, like channel 50 of FIGS. 8 and 10, terminates adjacent columnar portions of

end panel members

14 and 20. It will be observed, FIGS. 8-10, that the several panel members are mechanically interlocked. Thus, the left-hand edge of panel member 20 has a groove to receive a projecting tongue of panel member 19. Similarly, the left-hand edge of panel member 19 has a groove to receive a tongue of panel member 18. The opposite edge of panel member 18, FIG. 9, has a groove to receive a tongue of the wider centnal panel member 17. The left-hand edge of this panel member 17 also has a tongue which fits into a groove of panel member 16. Panel member 16 is identical in construction with panel member 13. Panel member 15 corresponds with panel member 19 and has a tongue at its lefthand edge portion, FIG. 10, fitting into a groove of panel member -14. This panel member 14 is of the same construction as panel member 20.

Each panel member has a plurality of rearward extensions. Thus, at the right-hand edge of panel member 19 there is provided a rib or extension 1% and, at the lefthand portion, two closely spaced

ribs

19f and 19g. These ribs have serrations extending lengthwise of the ribs and of shape generally complementary to the threads on fastening screws 48 extending through the web of channel member 50. The wider central panel member 17 has its parallel

serrated ribs

17 f and 17g intermediate its ends and in addition, has adjacent the edges reinforcing ribs 17m and 1711. Thus it will be seen that each panel member or a portion thereof is provided with a plurality of stiffening and supporting ribs respectively tightly clamped to the channel 50 and similarly clamped against

additional channel members

23, 51 and 52, two of which as shown in FIG. 7, extend across the upper ends of the panel members adjacent the openings 11 and 13. The several panel members are characterized by the provision of a plurality of such stiffening ribs, at least one of which is located adjacent the respective edge-portions of such panel members. In addition, stiffening ribs including provisions to receive cap screws are provided adjacent the tongue and groove interlocking assembly of adjacent panels. Thus while the cap screw 48 is effective through the tongue and groove connection 18p in cooperation with the stiffening rib 18e, for the panel 17 the serrated ribs 18,-f and 18g and the serrated ribs 16f and 16g are effective through the tongue and

groove connections

16p and 18p to clamp the

stiffening ribs

17m and 17m against channel member 50.

The

channel members

23 and 52 are secured to the

end panel members

14 and 20 by means of corner plates 29. The

intermediate channel members

50 and 51 are secured to the

end panel members

14 and 20 by means of T-shaped plates 54. There will be included, as required, additional panel portion supporting and reinforcing members for the panel structure, such for example, as member 55 which, it will be observed, is located intermediate the

openings

12 and 13 and has a length sufliciently greater than these openings so that it will be fastened to supported panel portions 15a and 18a and, in turn, support the

panel portions

16b, 17b and 18b (FIG. 1). Such intermediate supporting members may be located in any selected position, either in the position shown in FIG. 7 or nearer to one or the other of

openings

12 and 13.

The instruments 31--33 of 'FIG. 1 are mounted on the panel assembly as follows. Each instrument is provided with a rim or flange of greater width and height than the associated opening. Thus an instrument can be pushed through the opening from the front of the panel toward the rear thereof. For heavy instruments the associated flanges may have extending rearwardly therefrom studs which may be received by openings 57, FIG. 7, provided in

panel members

14 and 20. Inasmuch as the channel member 50 has an upper edge coinciding with the lower edge of opening 11, it will be seen that the weight of the instrument for that opening will be taken by the channel member. Thus the studs which will protrude through openings 57 serve to hold the instrument snug against the front of the panel and not to provide the whole support thereof from the panel members. The panel members can support the instruments, however.

Thus, an instrument mounted in opening 12 may have studs extending through openings 58 to which there will, of course, be applied washers and nuts.

An additional variation has been illustrated for the opening 13. Though the instrument does not appear in FIG. 7, there have been illustrated clamping plates 59, one of which is received on studs carried by the instrument and extending through the opening 13 adjacent the boundaries thereof. By tightening fastening nuts, the clamping plates 59 are pressed against the adjacent panel members to clamp the instrument in fixed position.

Referring now to FIGS. 8, 9 and 10, it is to be noted that while the section line =8, 9, 11 has been taken across the panel section 10a, and with the instrument 31 omitted therefrom, the reference characters for the parts are the same as for the panel section 10b, the parts being identical in the two panels. Referring to the right-hand panel section 20, FIG. 8, it will be observed that there is included a channel section 200 arranged to receive a threaded member 60 which by means of a cap screw 61 secures the T-shaped member 54 thereto. For ease in threading the screw 61 into member 60, a compression spring 62 holds the threaded member 60 against the inturned ends of the panel section 290 of panel member 20. The righthand end of panel member 20 has a rearwardly extending side to provide additional strength to the panel assembly and to conceal the T-shaped member 54 and the heads of the cap screws. The intermediate channel member 50 has its web portion secured to the

ribs

20 and 20g of panel member 20 as by a cap screw. The channel member 50 is also secured to the T-shaped member 54 as by cap screw 63 and by a cooperative nut and spring assembly like that described for cap screw 61.

As already described, the panel section 19 is clamped against channel member 59 as is each of the panel members 15-19. The left-hand panel member 14, FIG. 10, is identical with panel member 20, but it will be noted that it has been turned end-for-end. The left-hand T- shaped member 54 of FIG. 7 appears in FIG. 10 and has associated therewith cap screws 61a and 63a which in conjunction with associated fastening means like that of FIG. 8 secure together panel member 14 and channel member 5%. The left-hand panel member 14 of panel section 111a is bolted to panel member 26 of section 10b (FIGS. 1 and 10) by a plurality of bolts, one of which, the bolt 65, is shown in FIG. 10.

It will be observed that a spacer 66 separates the two panel members 14 and 2t} and that there is interposed between them a rectangular-shaped member 67 which provides at the front of the panel a back surface for the space between them in duplication of the back wall of a flute. In this connection, it will be noted that the groove 20: FIG. 8, is formed by a narrow, deeper groove adjacent a shallower and wider groove, the latter providing space for the spacer member 67, the deeper groove being provided to receive the tongue of other of the panel members when desired.

The panel assembly as a whole is rigid, mechanically interlocked, with as many weight-carrying columns and cross-channel members as needed to carry loads of any magnitude which may be imposed by instruments of widely differing character. The panel assembly is characterized by the multiplicity of panel members, all of ex truded material, such as aluminum, and which by reason of the provisions described above provide great fiexibility in assembly with the simplest of mechanical operations to provide most openings at almost any desired locations, together with an attractive appearance which may include flow charts and other symbolic representations of processes or systems for which the panel assembly is to be used.

What is claimed is:

1. A panel assembly of substantial width and height for instruments comprising a plurality of extruded panel members, each of said panel members along opposite edges having means for mechanically interlocking them one with the other, a substantial number of said panel members.

being of substantially different widths to provide differing distances from an edge of one panel member to an opposite edge of another panel member, the sum of the widths of selected panel members being at least equal to the width of an instrument to be carried by them to provide a horizontal dimension for a panel opening to receive such instrument, said panel members terminating lengthwise along horizontal lines corresponding with the height of the instrument at the desired location in the panel assembly whereby instruments may be mounted at selected positions determined by the length of the panel members above and below the instrument location, and cross-members extending across the panel members in line with an opening and secured to panel members adjacent said opening.

2. The panel assembly of claim 1 in which each said panel member has adjacent at least one edge thereof a rearwardly extending rib for strengthening said panel along the edge portion thereof, said strengthened edge through said mechanical interlocking means likewise providing strength for the edge of an adjacent panel member.

3. The panel assembly of claim 2 in which a plurality of said panel members are provided with spaced rearwardly extending ribs having serrations on opposing surfaces adapted to receive threaded screws at any selected position along the lengths thereof, and bracing members overlapping a plurality of said panels and secured thereto with screws extending into said serrated ribs for stiffening said panels to hold them in position to maintain said symmetrical pattern, said rib adjacent an edge thereof having the same rearward dimension as said spaced ribs for contact with the said bracing member.

4. The panel assembly of claim 1 in which said mechanical engaging means for said panel comprises tongues and grooves at adjacent edges of said panels for interlocking engagement one with the other.

5. A panel assembly of substantial width for measuring instruments comprising a plurality of panel members having at their respective longitudinal edges tongues and grooves disposed for interlocking engagement to form tongue and groove joints, each said panel member having rearwardly extending stiffening ribs adjacent each said joint, a cross-member against which said ribs are disposed to bear, said ribs of said several panel members having provisions to receive threaded fastening members adjacent each said tongue and groove joint for stiffening said panels by the clamping action of the ribs on opposite sides of each said tongue and groove joint against said cross-member.

6. The panel assembly of claim 5 in which a plurality of panel members intermediate the end panel members are made up of a plurality of portions of differing lengths to provide a plurality of openings through which instruments may extend, there being adjacent a plurality of said openings, channel members for additional stiffening of said panels and for carrying the weight of the instruments.

7. A panel assembly of substantial width for measuring instruments, comprising a plurality of panel members having on their front faces vertically extending flutes and ribs in symmetrical array, each of said panel members .along their longitudinal edges having means for mechanically interlocking them one with the other and in a spaced relation which maintains the symmetrical pattern from one panel to another, each said panel member having adjacent at least one edge thereof a rearwardly extending rib for strengthening said panel along the edge portion thereof, said strengthened edge through said mechanical interlocking means likewise providing strength for the edge of an adjacent panel member, said panel members having Widths to provide in a selected location of the assembled panel members an opening having a dimension extending from an edge of one selected panel member to an opposite edge of another selected panel member equal to the width required for a measuring instrument, said panel members in the region of said opening being of decreased length to provide a panel opening equal to the height of said instrument, and cross-members overlapping and secured to a plurality of said panel members.

8. The panel assembly of claim 7 in which a plurality of said panel members are provided with spaced rearwardly extending ribs having serrations on opposing surfaces adapted to receive threaded screws at any selected position along the lengths thereof, and bracing members overlapping a plurality of said panels and secured thereto with screws extending into said serrated ribs for stiffening said panels to hold them in position to maintain said symmetrical pattern, said rib adjacent an edge thereof having the same rearward dimension as said spaced ribs for contact with said bracing member.

9. A panel assembly of substantial width for measuring instruments, comprising a plurality of panel members having on their front faces vertically extending flutes and ribs in symmetrical array, each of said panel members along their longitudinal edges having means for mechanically interlocking them one with the other and in a spaced relation which maintains the symmetrical pattern from one panel to another, a plurality of said panel members including channel-shaped sections to provide columnar supports, each of said channel portions having inturned ends for supporting threaded members slidable lengthwise thereof, said panel members having widths to provide in a selected location of the assembled panel members an opening having a dimension extending from an edge of one selected panel member to an opposite edge of another selected panel member equal to the width required for a measuring instrument, said panel members in the region of said opening being of decreased length to provide a panel opening equal to the height of said instrument, and cross-members overlapping and secured to a plurality of said panel members.

10. A panel assembly of substantial width for measuring instruments, comprising a plurality of panel members having on their front faces vertically extending flutes and ribs in symmetrical array, each of said panel members along their longitudinal edges having means for mechanically interlocking them one with the other and in a spaced relation which maintains the symmetrical pattern from one panel to another, said panel members having widths to provide in a selected location of the assembled panel members an opening having a dimension extending from an edge of one selected panel member to an opposite edge of another selected panel member equal to the width required for a measuring instrument, said panel members in the region of said opening being of decreased length to provide a panel opening equal to the height of said instrument, cross-members overlapping and secured to a plurality of said panel members, and plastic strips generally of U-shape and complementary to the shape of said ribs, the thickness of the legs of each U-shaped strip being less than that of the grooves between adjacent ribs, whereby a pair of said legs can be pressed into a groove to provide substantially continuous coverage of selected areas of said ribs.

11. An instrument panel comprising panel structure having throughout its front face a plurality of vertical ribs and grooves, a plastic strip generally of U-shape and complementary to the shape of the ribs, the thickness of the legs of said U-shaped strip not exceeding half the width of the grooves between adjacent ribs, whereby said legs can be pressed into said ribs frictionally to engage the same to hold said strips in place and to form a continuous line of said plastic strip extending laterally across said ribs and grooves, said plastic strip having a width overlapping a plurality of said ribs, said strip including a plurality of U-shaped sections, each complementary to the shape of said ribs, the thickness of the legs at the edges of said strip being less than that of the groove between adjacent ribs and the thickness of the intermediate legs corresponding with the width of said groove, each intermediate leg having a notched end to impart flexibility to the end portion thereof, each said intermediate leg including along opposite edges beads to engage said ribs to hold said plastic strip in place.

References Cited in the file of this patent UNITED STATES PATENTS 2,062,094 Kip Nov. 24, 1936 10 Bloedow June 2-9, 1954 Dreyfuss Sept. 21, 1954 Aorarnson Oct. 16, 1956 Baldanza Mar. 31, 1959 OTHER REFERENCES Process Control by Graphic Panel by David M. Boyd, 11. Instruments, November, 1944, vol. 22, pages 1054 to Rowley et a1 Apt 27, 1937 10 1056- (Ph py in ivi i n