US2493769A - Machine for lead coating - Google Patents

Description

' Jan. 10, 1950 J, MA MN 2,493,769

\ MACHINE FOR LEAD COATING A Filed July 8, 1944 2 Sheets-Sheet 1 2: 22 1 J0 2'17 26\ -2 my fll! I 27 M Z;

w era or Jan. 10, 1950 J, MAGMN 2,493,769

- MACHINE FOR LEAD COATING Filed July 8, 1944 2 Sheets-Sheet 2 Patented Jan. 10, 1950 MACHINE FOR LEAD COATING Jacques Magnin, Chestnut Hill, Pa., assignor to Horace C. Knerr Application July 8, 1944, Serial No. 544,072

1 My invention relates to coating metal parts with lead as a lubricant to facilitate successive cold working operations changing the shape of the metal without necessity for intermediate annealings and/or picklings. Commercially pure lead is ordinarily used.

The main purpose of the invention is to produce a surface which is coated with lead and in which the lead adheres even after numerous cold passes.

A further purpose is to perform the lead coating of metals in a single operation.

A further purpose is to dip the metals to be coated through the flux into the lead, to move the articles to be coated back and forth within the lead and flux and to advance the articles along a path from the position of flux covering to the position of ultimate withdrawal from the molten lead, passing them through the flux and bath repeatedly but finally withdrawing the articles which have been coated by the lead.

A further purpose is to pass the articles to be coated through the flux into the molten lead,

- to expose the articles to different parts of the lead bath while shifting them within it and finally to withdraw the articles through a lead surface free from flux coating.

A further purpose is to dip the articles by a mechanical dipping device such as a conveyor chain, to heat the device so that it will not chill the lead and to reciprocate the articles within the molten lead during their progress from a point at which they lie below the flux to a point at which they are withdrawn from the lead.

Further purposes will appear in the specification and in the claims.

Figure 1 is a vertical section taken upon the line i--l of Figure 2.

Figure 2 is a fragmentary section of the structure of Figure 1 taken at right angles to that of Figure 1.

Figure 3 is a fragmentary section on line 3--3 of Figure 2 and is largely a side elevation showing a ratchet mechanism seen in Figures 1 and 2.

In the drawings similar numerals indicate like parts.

This application is a continuation in part of my abandoned application for Process or method of lead coating, Serial No. 466,195, filed November 19, 1942.

Under this invention the coating of lead applied to the surface of the metal functions as a so much superior lubricant that frictional resistance is greatly reduced even after many successlve cold passes.

7 Claims. (Cl. 91-122) I have discovered that excellent results can be attained by a dry dipping process without any preliminary wet process step such as, for example, a bichloride of mercury step. I use a salt derived from a metal which has affinity for (i. e. tends to alloy with) both the lead and the metal which is to be coated with the lead. I pickle in the usual way.

The salts preferably used are the chlorides, acetates, borates and sulphates.

In my dipping operation I dip through a flux which may cover a part only of the surface of the lead bath, so that the dipped metal may be withdrawn from a clear lead surface beyond a partition; Or the metal may be dipped into a completely flux-covered lead bath and withdrawn through the floating flux of the same bath.

Because each of themetals, tin, cadmium and antimony, etc. has an affinity for (this may be but another way of stating "will form an alloy with) the metal to be coated and with lead, its salts form molten fluxes by which the surface of the metal can be covered'with lead. This is true of metals generally, that they can be lead coated by dipping into a molten bath of commercially pure lead through a molten flux if the flux tends to alloy with the metal to be coated,

and also with the lead.

The lead coated articles are then withdrawn from the lead bath and allowed to cool when they are ready for such operations as drawing, wire drawing, rolling or deep stamping without intermediate annealing, picklingand again lubricating.

Because other materials than lead, whether definitely hardening the surface of the lead or forming an alloy with lead of inferior lubricant quality or not, act as impurities to reduce the effectiveness of the lead as a lubricant, it is quite desirable to have pure lead. It is difllcult, or at least expensive to get chemically pure lead but I have secured excellent results with a bath of what is known as commercially pure lead.

The principal benefit of my invention lies in the fact that the union of the lead with the outer part of the metal coated includes a permeation of the metal surface by the lead much like impregnation and possibly designated as impregnation. It may be a case of alloying with both metals.

I have found that a better coating of lead is secured where the metal to be coated, herein referred to generally as the work, is passed through the fiux and then is reciprocated or otherwise moved back and forward in the flux and lead. In order that the work may engage 'a ratchet plunger 36..

aeea'ree to be coated, as any such desired movement of the work articles can be effected by hand manipulation, dipping the articles into the bath in any suitable container, preferably in the form of a cage or basket, closed to retain the work pieces but permitting free flow of bath through 5.1 The basket and work piece content are moved about in the bath as desired. However, an effective movement can be secured by mechanism. For this reason a suitable machine has been illustrated in Figures 1, 2 and 3 and will now be described.

A platform3 is supported upon legs Ill and II, resting upon any suitable base, here shown as the upper rim l2 of the pot 5'. ,'The platform supports a motor I3 connected by belt l4 with a pulley ii. The speed of rotation is reduced through any suitable gear box IE so that the rate of rotation of 4 a position slightly to the right of that shown in Figure 2, after which the baskets and the hooks are slid to the left so that the hooks 43 come beneath guards 41, holding the baskets in position upon the flights, even when the baskets are turned upside down, as takes place when the sprocket chains are moving upwardly to the left (Figure 1) of the partition 3ll.

The lower parts of the sprocket chains pass about wheels 42 down in the bath, which wheels need not be sprocket wheels but may be pulleys merely. Bearings for the pulley shaft 43 are supported by stays 44 extending down from the partition 30. It has not been considered necessary to show the supports in detail. other than to indicate them at 45 in Figure 2.

The pot 5' is conventionally shown as seated in a concrete bed having a rim 41 upon which the flange 43 of the pot may be rested.

In order that the metal of the conveyor, such as the chains and the flights, may not chill the shaft I! will be lowenough for present. purposes.

ports connected with the chains at convenient points by attachment to tabs 23.

A partition or division plate 30 suitably supported from the side structure 3| and brackets 32, dips down into the lead bath 6 to prevent the flux 8 from distributing over the surface of the bath. The flux is otherwise confined by box 33.

I The conveyor bars on their downward strokes pass through the flux into .the bath.

The connecting rod 20 is pivoted to a rocker arm 34 at a distance (rocker arm length or throw) from shaft 23 large enough so that rotation of the crank arm- It will cause oscillation only of the arm 34. The arm 34 carries a holder 35 for e plunger is drawn toward engagement with the teeth of the ratchet wheel ."by spring 31, capable of being withdrawn therefrom by handle 38 so that the ratchet disc and sprocket wheels can be rotated by hand to anyextentdesired when the ratchet plunger 36 has been withdrawn from the teeth of the ratchet wheel. This makes it possible to turn the conveyor to any point desired, moving baskets 33 by the flights upon the sprocket chains through the flux back and forth across the flux line.

The reciprocation seems .to have a scrubbing action and if the metal to be coated be finally taken out of the lead at a lead surface free from flux there seems to be no film of flux on the coating. Even where the metal coated comes out through flux there is little trace of flux and the flux can be selected to be as little objectionable as possible.

As seen in Figure 2 the preferably closed work cages or baskets for the articles to be coated are hung by hooks 40 from bars or flights 21. 1 The hooks are connected with the bars or flights in lead bath, a heater is supplied, including a gas pipe 43 controlled by valve 52. It discharges gas through a burner nozzle 5| so that hot air at 52 may be fed through an upright pipe 43 and a manifold 34. The manifold distributes the hot products of combustion against the chain, preferably on the down side of the conveyor, heating the conveyor sufficiently so that there is no chilling of the molten lead. The bath may also be heated separately as by an electrical heating unit within the bath. Heater I! is. conventional and is supplied with current through wires 56 protected by conduit 31.

Notwithstanding that there is individual merit in the particular mechanismshown and that this mechanism will be claimed, the drawing is intended to be conventional to the extent that it represents one mechanism by which the haskets for the metal to be coated may be moved back and forward within the lead bath and across the fluxline. I

In operation, articles to be coatedand subsequently to be cold-processed are placed within the basket and the basket is attached to a flight of the conveyor, after which the ratchet plunger is withdrawn from the teeth of the ratchet wheel while the sprockets and chains are turned to carry the basket through the flux and into the lead bath and back again so that with reciprocation due to the mechanism the basket will reciprocate back and forward past the flux line.

The ratchet tooth is reset within the ratchet wheel at such a point in the revolution of crank arm it that the reciprocation will take place initially over the desired range in the depth of the molten pool of lead. The revolution of the crank arm It will cause oscillation of the arm 34 with corresponding oscillation of the ratchet wheel and the sprocket wheels, and with successive reversals of limited movements of the sprocket chains.

When there has been sufficient reciprocation of the basket for the articles properly to be coated, the ratchet plunger is withdrawn from the ratchet wheel, the sprocket chains are advanced a distance suflicient to carry the basket through the lead and out to a part of the bath at which reciprocation is within 'thelead alone and the articles are withdrawn. The ratchet plunger is allowed to enter a diflerent notch in the ratchet wheel. Reciprocation of a new basket is begun while other baskets along the conveyor are reciprocated where they may be.

While the movement of the basket has been called reciprocation, because during a considerable part of the distance travelled the container will move in a straight line and back again, as seen in Figure 1, there may also be oscillatory movement of the basket where it travels about the curved portion of the wheel at the bottom of the bath. Adjoining the straight stretches of the sprocket chains there will be movements which will be partially reciprocations and partially oscillations. It is my intention ot use reciprocatio to cover these various movements.

When there has been suflicient reciprocation of the baskets within the molten bath and flux, the ratchet tooth is withdrawn from the ratchet wheel and the sprocket chains are turned to bring the baskets out from the bath, the container is drained in a trough 58 or other resting place and is subsequently cooled.

The coating is followed by cold-process working in dies or by other tools securing the lubricant advantages.

The invention has been quite successful in making cartridge casings from a cupped or flat blank which is first cupped and then successively drawn to the final size of the casing needed. With the lead coating I have performed five successive drawing operations before annealing and then, with a controlled atmosphere I have been able to anneal'without losing the lead coating nor the quality of the lead coating, continuing to perform other successive drawing operations.

The. lead coating forms a basis for continuing cold processing without annealing and these operations are contemplated in connection with the coating. i

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefitsof my invention without copying the structure shown, and I, therefore, claim all such in so far as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention what 1" claim as new and desire to secure by. Letters Patent is:

1 In a device for dipping objects through a molten flux into a molden bath of lead, a container for a molten bath, a conveyor, wheels guiding the conveyor, located at the upper end of the container to bring the objects outside the bath and at the lower end of the container to immerse the objects within the bath, between and about which wheels the conveyor stretches extend, means for mounting upon the conveyor the objects to be coated, means for oscillating the wheels at the upper end and throughout an adjustable range, and means for releasing the oscillating means from the wheels for the conveyor and setting it at a diflferent point to oscillate the conveyor throughout a diiferent range, thereby positioning the objects to be coated at a new point for further oscillation.

2. In a machine for dipping objects to be coated through a molten flux. into and from a molten bath, a container for the said bath, a conveyor movable into and out of the said bath, wheel supports for the conveyor above the bath and within the bath, containers for the objects to be coated adapted to be mounted at variant points upon the conveyor, means on the conveyor for mounting the containers, a ratchet wheel adapted respect to the flux level.

to drive the conveyor and having teeth, means for driving the conveyor from the ratchet wheel, a plunger cooperating with the ratchet, engageable and releasable with and from the said teeth, an arm carrying the plunger and pivoted adjacent the ratchet axis, and rotary means for oscillating the arm, the position of any given portion of the conveyor moved by said oscillation being determined by the point in the ratchet wheel at which the plunger engages said wheel.

3. A pot having a molten pool therein, and flux floating on the pool, means for confining the flux to one part of the pool, a conveyor having stretches reaching down through the flux and up through the surface of the pool, free from the flux, means. for securing articles to be coated to said conveyor, oscillating means for moving the conveyor stretches alternately up and down and means for changing the point upon said conveyor at which said oscillating means is connected.

4. A holder for molten treating material having a molten bath therein, a conveyorguided into and out of the bath at points above and within the bath, means for attaching the objects to be treated upon said conveyor, means for shifting the conveyor up and down and means for adjusting points at which the shifting means is connected with the conveyor.

5. A holder for molten coating material having a molten bath therein, a conveyor having flights guided into and out of the bath at points above within the bath, means for attaching to the conveyor the objects to be treated, means for shifting the conveyor up and down'and means for heating the conveyor flights so as not to chill the molten bath.

6. A pot-having a molten pool therein and a flux floating on the pool, means for keeping a portion of the pools surface free from flux, means for dipping articles to be coated through the flux into the pool and bringing them out through the portion of the pool surface free from flux and oscillating means for moving the dipping means to carry the articles into the pool through the flux and remove them from the pool through the flux successively and for changing the level at which the dipping means oscfllates the articles with '7. A pot having a molten pool therein and a flux floating on the pool, means for dipping articles to be coated into the pool through the flux and :out again, reciprocating them backward and forward through the flux and ratchet adjusting means progressively varying the extent to which the articles are submerged in the pool.

JACQUES MAGNIN.

REFERENCES CITED The following references are of record in the

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