US1571541A - Plated metal - Google Patents

Description

` Feb..\2 1926. 1,571,541

. V. D. DAVHGNON PLATED METAL Filed July 25, 1924 y Patented Feb. 2, 1926.

UNITED STATES PATENTo Frio VICTOR D. DAVIGNON, OF NORTH ATTLEBORO, MASSACHUSETTS, .ABSIIIGN'OB G-li ',ERAL PLATE COMPANY, 0F ATTLEBOBO, MABBAOHUBETTB, A CORPORATION 0F MASSACHUSETTS.

PLATED METAL. f

To all whom it may concern.'

Be it known that I, VICTOR lD. a citizen of the United of North Attleboro, in the county .of Bristol and State ofl Massachusetts, have invented an Improvement in Plated Metal, of which the following descri tion, in connection with the accompanying rawings, is a specification, like characters on the drawings representing like parts.

This invention relates to plated metal and consists in improvements in that class of plated product which comprises a backin or base of relatively .cheap metal, surfaced with a thin film of relatively precious metal, produced by a process of mechanical attenuation. t

In the production of plated metal of this class it is customary to start with a block or bar of cheap base metal, such, for exemple, as brass, on which is placed a thin sheet of precious metal, such as gold, with an interposed thin sheetv of fusible solder, such as silver solder. The recious metal is then fused to the base metaFin a soldering furnace, and the blank comprising this composits block or-bar subjected to a'rolling, drawing, or other mechanical process designed to reduce the aggregate thickness* in a' unitary piece, such process being carried DAvIaNoN,

- to` a point where the precious metal'is left as a thin surface coating) on the usual relatively thick base metal ody.

In the production of the more inexpensive grades of plated ware, the mechanical attenuation is carried to the point where the surface coating is reduced to a very thin hn and, if carried far enough, where the particles of the base metal tend to co-mingle at p'oints in the'surface with particles of the precious metal. This is apparently due in part to the working of the precious metal into the underlying soft base metal so that the continuity ofthe precious metal is broken at intervals and becomes replaced at the surface by particles of the base metal. It also appears to be due to the fact that the solder, when fused, tends to soften and draw into its mass more or less of both the precious metal and the base metal and cause them States, and a resident successlve rolling actions,

`ticles on the precious metal plate.

Application med my as; 1924. serial no. 72u34.

further co-min le the two metals and the base meta to the surface. vBetween it `is necessary to sub]ect the product to a high annealing temperature which again gives opportunity for this cosmingling action, and this el'ect is further aggravated by the subsequent rolllng process.

In the. production of inexpensive gold'or other precious metal rolled plate, the point is soon reached where the product is subto co-mingle, the rolling action tending-t0 3W g ject'to discoloration orl oxidization due to the effect of exposure of the base metal par- This readily becomes apparent by subjecting the `material to the well known'v test with nitric acid. This characteristic renders the product less available foruse in the jewelry manufacture or other similarpurposes. v

The present invention contemplates the production of mechanical processes similar to those heretofore employed of a plated metal product comprising a surface of gold or other precious metal on a base of relatively inexpensive metal where the precious metalv surface may be reduced to a thinness heretofore incapable ofl resisting the acid test, but nevertheless presenting a resist ance to the acid test and to discoloration and tarnishing similar to that of heavier and more expensive plate.

The invention will be best understood by reference to the following description when taken in connection with. the accompanying illustration of one specific embodiment thercof, While its scope will be more particularly pointed out in the appended claims.

The drawing shows more or less diagramc matically and conventionally a cross section of a composite bar or block used in carrying out one'form of theherein described process. vTo illustrate one this invention, the tively cheap base as brass or nickel silver, is first procured. The dimensions are immaterial, but for the sake of.. illustration the block may be 12 or 14 inches long, -from 2 to 4 inches wide method of carrying fout block or bar 1 of a relawhich may be metal, such, for example,

and of ai inch thick. on top of this block or bar is placed a thin sheet 2 of solder which, for example, may be silver solder sheet 3 of metal suciently malleable to respond to the rollingv'process, but relatively ard as com ared to the base metal so as to present a ard, tenacious backin onl which the precious-metal may be effectively rolled. Such metal should also be capable of withstanding-high temperatures, such, for example, as 12502132,-Wlnch approximates those customaril employed in the soldering furnace and t e annealing ovens, and of so separating the base metal. from lthe previous metal under such conditions that the fusion of the solder can have no tendency to cause particles of the precious metal to co-mingle with the metal of either 'the base or the backing. I have found that a suitable metal for thispurpose is ordinary machine `steel. This has sufficient malleability to undergo the rolling operations without damage to the product and sufficient hardness to permit the precious metal to be rolled out into a th'Lnner unbroken film than has heretofore been prac.- tically obtainable. The best results may be had by using cold rolled steel.

The sheets 3 of backing metal may be of any desired thickness, but in the illustrative example a sheet .010 to .0M of an inch thick will sufice. On the top of the backing sheet 3 there is then laid another sheet .ofA solder 4,' similar to the sheet 2, and

on top of these assembled layers there is placed a sheet 5 of gold or such other precious metal as is to be used for the plating operation. The thickness of the preciouszzmetal sheet will depend on the quality of the plate desired, and in the illustrative example might vary from .01 to .25 of an inch, or might even be outside of these limits.

The assembledparts are then clamped together or otherwise placed under pressure in the soldering furnace and fused together, making a blank in the form of a composite block composed of the base metal, the precious metal sheet and an interposed sheet of relatively hard but malleable and heat resisting metal.

If desired, the backing 3 might be irst assembled and fused to the base metal block and the resulting composite block then assembled With the precious metal and the latter fused thereto, or the backing sheet and precious metal might first be assembled and united and then together united to the base metal.

The compositeblock is then subjected to the usual mechanical operation heretofore practised, such, for example, as a succesform of plate, the composite block as de-v scribed may be rolled to a certain degree `of thinness and then cut into smaller portions which may be fused each to another block of base metal, and the latter each subjected to further mechanical thinning operation. Or, on the other hand, if desired, the base of the plate, instead of consisting of the cheap metal base 1 and the backing 3, might consist entirely -of machine steel.

In the use of this composite material inv the rolling or drawing operation, the gold or other precious metal may be reuced to an unusual thinness Without disruption of its continuity. The base metal is prevented by the steel backing from co-mingling Wit the reciousmetal, either through 'the action o mechanical attenuation or through the agency of the fused solder.. The backing is not only too hard and dense to work into and through the precious metal coating, but offering, as it does, a hard, smooth and dense surface over which precious metal is Worked, as by rolling, the latter may be carried to a more advanced point than heretofore While still maintaining an unbroken film of the precious metal.

A relatively cheap plate may thus be produced having durability and Wear resisting qualities heretofore possessed only by higher grades of plate. Such plate is capable to withstanding Without effervescence the usual acid test Which consists in applying to the plate so-called 36 degree nitric acid.

The same principle may be obviously applied to the production of double plated material; that is to say, Where the plated Ware presents a plated surface on both its opposite sides, each surface having an acid resisting backing.

While I have herein shown and described for the purposes of illustration one specific embodiment of the invention, it is to be understood that the same is not limited to the details hereof but that extensive deviations may be made therefrom Without departing from the spirit thereof.

I claim: p 4

l. cA- composite plated metal having a finely attenuated surface of precious metal, a thin backing of steel, and a relatively thick base of metal relatively soft as compared With the backing and relatively cheap as compared With the surface.

2. A composite plated metal having a finely attenuated'surface of precious metal, a thin backing of malleable steel, and a relatively thick hase of metal relatively soft a backing sheet of steel united thereto, andv as compared with the backing and relaa surface sheet of preciousn metal united tively cheap as compared with 'the surto the backing sheet. 10 face. v In testimony whereof, I have signed my 5 3. A com osite metal blank for producname to this specification.

ing a plate product comprising a relatvely thick body of relatively cheap base metal, VICTOR D. ])AVI(;`rl\T( )l\T.V

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