US2087330A - Composite article - Google Patents

Description

July 20, 1937. w. H. PAGENKOPF ET Al. 2,087,330

COMPOSITE ARTICLE Filed NOV. lO, 1934 Patented july 20, 1937 i" for Application November ld, i934, Serial Na, i525@ l Claimso This invention relates to composite articles, and more particularly to terminal banks for rotary telephone switches.

One type of terminal bank used in telephone selector switches includes a plurality of superimposed or piled up rows of individual terminals arranged in groups of two rows spaced a desired distance apart by an insulator blank, the terminals of each row being uniformly spaced in a lateral direction. At one side this insulator blank lies flush with the ends of the terminals so as to space them a definite distance apart. Each group of terminals is spaced from the adjacent group a desired distance by a pair of spaced insulator blanks and a metal ground plate filling the space between the blanks. The whole pileup of uniformly spaced groups of terminals with their insulator blanks and ground plates is clamped under pressurebetween upper and lower mounting plates with the terminals projecting on either side from the insulator blanks and the ground and mounting plates. ln this type of terminal bank it has been difficult to provide a uniform desired spacing between the two rows oi terminals of each group as well as between the groups due to variations in the thickness of the individual insulator blanks used in the pileup. Furthermore, it has been the practice to rely chiey on the carefulness in carrying out the assembly operations to prevent the individual terminals from being dislocated during their initial assemblage in the pile-up and in their iinal assemblage the pressure exerted on the clamped pile-up has been relied upon to maintain the individual terminals in their desired spaced relation. Due to the arrangement of the terminal bank above described it is not possible to provide vertical guides for positively locating the terminals during assembly. l

An object of the present invention is tol'- provide an improved composite article wherein the parts thereof have a desired spacing and are rrnly united to prevent relativedisplacement therebetween. j y

in accordance with the above objects, wherein one embodiment of the inventionQis applied to the production of terminal banks of the' type hereinbeiore referred to, the terminal banks are built up from a plurality of previously formed (Cl. it-UBM) blank for each terminal unit is selected for thickness so as to provide a desired overall height at the completion of -its assemblage with the terminals. Thereafter the conducting terminals are deposited in a desired spaced arrangement upon the coated surface of the phenol fibre blank which is supported on a fixture. The blank with the terminals thereon is then placed between heating and compressing members and subjected to heat and pressure to bring them to a desired overall height during which the dry coating of phenol varnish upon the blank is first softened, thereby yielding under pressure, and while pressure is maintained the softened phenol varnish is cured. rThis results in a terminal unit of a desired overall height with the terminals firmly adhering 'to the blank in their desired spaced arrangement thereon. The method of assembling the units into a completed 'terminal bank will e described in detail hereinafter.

Other objects and advantages of this ini/en tion will more fully appear from the following description taken in connection with the accompanying drawing, wherein- Fig. l is a top plan view of an assembled tei'- minal bank comprising a plurality of superiinm posed composite terminal units embodying the features of this invention;

Fig. 2 is an enlarged fragmentary vertical section taken on the line 2 2 of Fig. l;

Fig. 3 is a fragmentary vertical section, still further' enlarged, taken on the line 3--3 of Fig. 2;

Fig. l is a side view of a iixture which may be used in assembling the phenol fibre phenol varnish coated blanks and the superimposed conducting terminals;

Fig. 5 is a fragmentary top plan view of Fig. l on a reduced scale, and

Fig. d is an enlarged vertical section taken on the line @-55 of Fig. 5.

rl terminal bank comprising a plurality of superimposed composite terminal units embodying the features of this invention may be produced by first producing a number of arcuate-shaped strips or blanks l@ and il of different areas and thicknesses, each serving in the nished terminal bank in a particular manner which will be reierredto hereinafter. The blanks lll and Il are formed from sheets of different areas and thicknesses, comprising laminations of fibrous material, such as paper or fabric, each lamination thereof having been impregnated with a phenolic condensation product and the whole united and completely cured by the application of heat and pressure to produce a sheet of an incompressible, infusible, and insoluble character and a desired accurate thickness, within tolerance limits, the blanks lll and ll then being cut from the sheets. The sheet material just described is commonly known as phenol fibre.

The sheet of phenol b-re from which the blanks lll are formed and previous to the cutting of the blanks therefrom is preferably fairly heavily coated on one of its side surfaces, as indicated at l2 (Figs. 2 and 3), with a thermosetting resin in solution, such as phenol varnish, which is allowed to dry. The resin of course is not completely cured at this time. Phenol varnish which has been found suitable for coating the surface of this blank is of a type which upon drying for a suitable period of time will be dexible and non-brittle, but upon the application of heat and pressure it will rapidly change from a dry to a tacky state and then change from a tacky to a dry hardened and fully cured state, thus giving it good adhesive dualities. This coating if of phenol varnish, which. after curing is infusible and insoluble, has eircellent electrical insulation properties at high humidities.

"While a phenol varnish comprising a solution of a phenolic condensation product is preferred for the coating, other thermosetting resins which harden under the action of heat may be employed, providing their dielectric properties are satisfactory.

Each terminal unit in the embodiment illustrated includes ten conducting terminal strips iii of a desired thickness and contour which may be formed from brass sheets. .Dit the rear each terminal is extended and offset to form a soldering portion iti.

Referring particularly to Fig. 2 a plurality of perforations ill are formed in the phenol fibre blanks lil and il, which in the assembly of the blanks with the conducting terminals i5 into a terminal unit are alined, the perforations being used in the assemblage of the blanks and the terminals l5 into terminal units and subsequently in the assembling of a plurality of terminal units into a finished terminal bank.

in uniting the phenol libre blank l0 having upon one of its side surfaces a fairly heavy coating it? of dried phenol varnish of the type previously described and a set of ten terminals into an integral terminal unit, the phenol varnish coated blank llt, which is selected as to thickness so as to provide a desired overall height when finally assembled with the terminals l5 and thereby an accurate and uniform spacing between the rows of terminals, is mounted upon an arcuate-shaped fixture (Figs. 4, 5 and d) comprising a base ifi having a plurality of vertically disposed metal alining pins i9 which extend freely through the spaced perforations il? formed in the blank. The opposite arcuate sides of the base l are provided with vertical flanges 20, each of which upon its upper surface is formed with a plurality of notches or nests 2l having a predetermined uniform spacing and depth.

After the accurate positioning of the blank lil upon the base lil in the manner described the assembling xture is located under a mechanism (not shown) which includes ten supply magazines for the terminals l5 having discharge openings for each of the terminals, the openings being spaced for alinemcnt with the nests 2l in the opposite flanges 2B of the base I8 when the xture is correctly located thereunder, for supplying to and locating the terminals on top of the phenol varnish coated upper surface of the blank l0 in their accurate desired positions. rI'he terminal supp-lying mechanism is then operated and ten 'terminals i5 are deposited on top of the blank I0, the opposite ends of the terminals being located in the nests 2l which serves to prevent their displacement-relative to each other and to the blank in subsequent assembly operations, their relative positions being shown in Figs. l and 5. The terminals may of course be placed in the nests 2| by hand if desired. lThe assemblage of the superimposed blank l correctly positioned and retained upon the base E8 by the pins i9 and the terminals ib correctly located and retained on the blank by their opposite ends positioned in the nests 2l of the flanges of the base i8 is then inserted between compressing members (not shown), the upper one being a heating member, the projecting ends of the pins lil being alined with suitable apertures provided in the adjacent heating member. The lower surface of the heating member is preferably formed with extending 2 portions which have a lateral spacing similar to that of the terminals i5 and alined therewith so that the heat is applied directly to the upper surfaces of the terminals Where it is needed to soften the phenol varnish coating on the blank l (i, directly under the terminals, and consequently the coated surface of the blank between the terminals is not so greatly affected. The heating and compressing members are then relatively moved to compress the assemblage of the blank lil and the terminals l5, the fairly heavy coating of phenol varnish directly under the terminals irst softening and then yielding under pressure until a desired overall height of the blank and terminals is reached, which is reached when stop surfaces on the heating and compressing members engage each other. The heating member above referred to is heated in anysuitablemanner and the heat applied to the phenol varnish not only softens the varnish. to cause it to yield, but

is applied long enough to cure and harden the varnish as is Well understood in the art of thermosetting resins. Thereafter the assemblage comprising the blank I 0 and the terminals l 5 is cooled either by room temperature after ceasing to apply heat to the heating member or by applying a cooling medium thereto by suitable means and simultaneously therewith the compressive action on the superimposed blank and terminals is maintained. The finished terminal units are indicated by the numeral 22 (Figs. 2 and 3). With the termination of the cooling step the terminals l il are firmly united to the phenol varnish coated top surface of the phenol fibre blank l0 due to the adhesive action of the phenol varnish between the terminals and the blank, which varnish upon the setting or baking thereof becomes hard and cured and provides a firm bond between the parts. rThe resultant integral structure has a desired overall height and the terminals l5, due to their adherence to the top surface of the blank it, will not be dislocated in subsequent handling of the terminal units 22 prior to or during the iinal assemblage operations into a finished terminal bank.

aoaaseo It is to be understood that during the application of heat and pressure to the superimposed phenol fibre phenol varnish coated blank l@ and the terminal l5, no change in the individual thickness of the blank I occurs, since the blank, as hereinbefore described, hasbeen completely cured before assemblage with the terminals l into an incompressible, infusible, and insoluble blank.

Since the heating and compressing operations may be performed in'any convenient apparatus, a disclosure of a specific apparatus for accomplishing these operations is not believed necessary to a full understanding of this invention and have been omitted.

Although in the above described method of forming terminal units to a desired overall height it is stated that the phenol fibre blank l@ and the terminals l5 are of selected thicknesses and the blank as being fairly heavily coated with a thermosetting resin, which upon being softened yields under pressure to a thickness governed by the stops on the heating and compressing members toprovide a desired overall height to the unit; if the blanks and terminals are sufficiently carefully selected as to thickness the stops may be omitted and suiiicient pressure applied to insure a layer of coating material of negligible thickness between the blank and the terminals. In this case less coating material is required.

In producing a multiple unit terminal bank7 referring particularly to Figs. l and 2, which includes a pile-up of predeterminedly spaced and alined preformed terminal units 22 of the type previously described, there are provided top and bottom mounting or clamping plates 23 of metal, the top plate only being shown. rlhe plates are arcuate-shaped and formed with a plurality of perforations 2li similar to and spaced for alinement with the perforations lll formed in the phenol fibre blanks ld and lll. in assembling the bank thebottom plate is `first positioned on an assembling fixture (not shown) provided with a plurality of removable vertically disposed metal alining pins which register with the alined perforations of the various terminal units 22, spacers, and plates used in building a nished terminal bank. Upon the top of the lower clamping plate is positioned a preformed terminal unit 22 and upon the top of the latter a phenol fibre blank ll of the type previously described. Another preformed terminal unit 22, only reversed in position so that the lower surfaces of the conducting 'terminals l5 will abut the upper surface of the phenol nbre blank lll, is then positioned on top of the latter blank. This is followed by placing an arcuate-shaped perforated metal ground plate 25 of a desired thickness on the upper surface of the phenol fibre blank lil of the last mentioned terminal unit 22. Thereafter another preformed terminal unit 22 with the terminals l5 thereof uppermost is positioned on the top of the ground plate 25 and then the order of assembly of the preformed terminal units 22, phenol fibre spacer blanks il, and ground plates 25 is continued until the desired number of terminal units have been superimposed upon the pins of the assembling fixture to provide a terminal bank of the desired number of terminals. Upon the uppermost terminal unit 22 of the bank the upper mounting or clamping plate 23 is positioned. Thereafter the pins of the assembling fixture are removed, one or a small number at at time, preferably in the following manner: First, one of the end pins is removed and a screw 2t is passed through the alined perforations of the blanks and plates, and then the opposite end pin is replaced by a screw 26, and so on until all of the pins have been replaced by screws. Since the screws 26 accurately t the perforations of the blanks and plates they serve to iirmly hold the units 22 and plates from relative longitudinal and lateral displacement, when removed from the fixture. The assembly with the associated screws Zit is then removed from the fixture .and nuts are then threaded onto the ends of the threaded ends of the screws and tightened until the required overall height of the assembled terminal bank is reached. i

llhe upper and lower mounting or clamping plates 23 are formed with the usual perforations 2l in order that the terminal bank may be secured to the switch frame. It will be noted, referring to Fig. l, that the conducting terminals l5, which are disposed close to the screws 2E, are notched, as indicated at 28, upon opposite edges and in line with the screws so that no short circuit or path of low conductance between the terminals and the screws at this point can occur.

From the above description it will be apparent that by practicing the method of the invention a terminal bank may be economically and efflciently produced wherein the several rows of preformed terminal units predeterminedly spaced from each other by insulating and metal spacing strips and plates, respectively, of selected accurate thicknesses will have a desired accurate spacing upon complete assemblage into a bank and the individual terminals of each row will be maintained firmly in their desired laterally spaced relation. This primarily results from the described methods of preforming the individual terminal units 22 from completely cured phenol nbre strips lil of selected thicknesses and having the described surface coating lf-l of phenol varnish on one side with the conducting terminals l5 accurately arranged on top of the coated surface. rfhe assembled strip and terminals comprising the terminal unit is `thus formed into a Yfirmly united composite structure of a desired overall height wherein the strip and terminals are firmly bonded to each other due to the adhesive action of the phenol varnish coating on t-he phenol Fibre strip upon completion of the heating and compressing steps of the method.

While a manual method of assembling the preformed units 22 into completed banks has been described, the terminals are sufficiently rmly attached to the insulating strips that if desired.

machine methods of assembly may be used.

l/Vhle the foregoing describes but one embodiment of a composite article of this invention, it will be understood 'that the invention is capable of application to other types of articles and is only limited by the scope of the appended claims.

What is claimed is:

l. A unit for use'in building a multiple unit terminal bank, said unit comprising an insulating strip, a series of terminals and an adhesive securing said terminals to said strip, said adhesive consisting of a thermosetting resinous material cured under heat and pressure to make a good bond between the strip and the terminals and to bring 'their combined thickness to a desired value.

2. A terminal bank comprising-a plurality of units, each unit comprising an insulating base having 'terminal strips secured thereto by a fully cured thermosetting resin, the units being individual and preformed to a predetermined size and means for clamping the units together to form a single unitary structure.

3. A terminal bank comprising a plurality of units, each unit comprising an insulating base having terminal strips secured thereto by a fully cured phenol varnish, the units being individual and preformed to a desired overall height, and means for clamping the units together to form a single unitary structure.

4. A terminal bank comprising a plurality of units, each unit comprising a base of completely cured phenol bre of an accurate thickness having terminal strips secured thereto by a fully cured thermosetting resin, the units being individual and preformed to a predetermined size, and means *for clamping the units together to form a single unitary structure.

5. A terminal bank comprising a plurality of units, each unit comprising an insulating base of an accurate thickness having a plurality of laterally spaced metal terminal members of a desired thickness secured. thereto by a fully cured thermosetting resin, the units being individual and preformed to a desired overall height, and means for clamping the units together to form a single unitary structure.

6. A terminal bank for telephone exchange systems comprising a plurality of units, each unit comprising a base of completely cured phenol bre of an accurate thickness having a plurality of laterally spaced metal terminal members of a desired thickness secured thereto by a fully cured phenol varnish, the units being individual and preformed to a desired overall height, and means for clamping the units together to form a single unitary structure.

7. A. terminal bank for telephone exchange systems comprising a pile-up of units alternately reversed in position and alternate elements of insulation and electrical conducting material of a predetermined accurate thickness between successive terminal units, each of said units comprising an insulating base having a plurality of laterally spaced metal terminal members of a desired thickness secured thereto by a fully cured thermosetting resin, the units being individual and preformed to a desired overall height, and means for clamping the units together to form a single unitary structure.

WALTER I-lf. PAGENKPF. RODNEY HANSN.

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