US2061133A - Process for making spindles for lamp standards and the like and products thereof - Google Patents

Description

'A. H. BELL Nov. 17, 1936.

v PROCESS FOR MAKING SPINDLES FOR LAMP STANDARDS AND THE LIKE AND PRODUCTS THEREOF Filed Dec. 14, 1934 2 Sheets-Sheet l INVENTOR. ALLA/v H BELL .m 1 II,

AYKRNEY.

Nov. 17, 1936.

A. H. BELL 2,061,133 PROCESS FOR MAKING SPINDLES FOR LAMP STANDARDS AND THE LIKE AND PRODUCTS THEREOF Filed Dec. 14, 1934 2 Sheets-Sheet 2 INVENTOR. ALLAN/i BELL,

ATTORNEY.

Patented Nov. 17, 1936 PRQCESS FQR MAKING SPINDLES FOR LAMP STANDARDS AND THE LIKE AND PRODUCTS THEREOF Allan H. Bell, Alexandria, Ind, assignor to The Mantle Lamp Company of America, Chicago, lill., a corporation of lillinois Application December 14, 1934, Serial No. 757,499

9 Claims.

My invention relates to an improved process for casting hollow spindles for the standards of floor lamps, preferably by the slush method of casting, in such a manner that the spindles extend as integral and unitary structures, each substantially from the base of its standard to the head thereof, the spindle being adapted to be connected directly with the base and head por tion of the standard, thereby making the usual internal tie tube unnecessary.

In casting parts for standards of the kind referred to, it is of the utmost importance that the molds shall facilitate the accurate casting of desired ornamentation on said parts, that the molds and cast metal shall produce smooth, finished surfaces on said parts, and that the mold for any particular part may be used repeatedly in making said part, to the end that a great many of said parts may be made in the same mold and be identical with each other, and that the cost may be less than if a new mold were required for each piece cast.

To meet the requirements mentioned, the molds are made of metal or alloy, for example, brass or bronze, having a much higher melting point than that of the metal or alloy used in making the castings in said molds, said molds being referred to for convenience herein, as metal molds. So-called White meta has been found to give satisfactory results in casting lamp standard parts in metal molds, as it may readily be selected to have the requisite melting temperature and also to provide the strength and finished surfaces of castings required for such parts. Such white metal is preferably an alloy consisting, for example, largely of zinc, the percentage of which may in some cases be as high as 95%, and the other metals in said alloy may, for example, be aluminum and copperin desired proportions. As used herein, I mean by the term white metal, any metal or alloy having physical properties adapting it to be successfully cast in metal molds, to produce castings having finished surfaces and the strength and hardness required of the castings.

In casting hollow parts of white metal in metal molds, where it is not important that the inner surfaces of the parts shall have exact contours or a smooth finish, the sludge method of casting is eifectively used, as it materially lessens the cost of making the castings and at the same time produces castings having equally as good finish and strength, as though cores were used in making said hollow parts. For lamp structures having electric bulbs, it is desirable that the parts thereof shall be hollow to permit threading electric wires therethrough to supply the bulbs with current.

Heretofore, in using white metal in slush casting the spindles for the standards of floor lamps in metal molds, serious limitations have developed as follows. The white metal adapted to the purpose has high coefficient of contraction which may be as great, for example, as 1 3' of an inch per foot; it is usually desired that said spindles shall have at their ends, laterally projecting ornamental parts; the metal molds are rigid and do not yield under the pressures upon them produced by the cooling and contracting castings within them; as a result, for thicknesses of spindle wall that are practically permissible, the strains developed in the hollow spindle castings by their contraction in the molds, where the spindles have exceeded 12 to 18 inches in length, have exceeded not only the limit of elasticity, but also the limit of rupture of the casting at its weakest section, and such attempts to cast spindles longer than from 12 to 18 inches have failed, due to the rupturing of the castings. In view of this, since spindles of floor lamp standards must have a length of from 30 to 40 inches, it has been the practice heretofore in casting hollow spindles for such standards, to cast them in sections longitudinally, each at least as short as the limiting length permitted by the wall thickness of the spindle, and to assemble them on and hold them together by tie rods or tubes which are secured at their ends to the bases and heads of the standards.

By my improved process, I provide a metal mold for the spindle in which the mold proper has the same length as the complete spindle, less any contraction that occurs in the cast spindle, the mold being so made as to permit the entire cast spindle, with the possible exception of one end portion, to contract freely in and longitudinally of the mold as the cast metal chills and cools in the mold. Spindles so cast may have projecting ornamentation, providing said ornamentation interlocking with the mold to prevent free longitudinal contraction of the cast spindle in any case, is restricted to one end portion of the spindle and so related to the cross-section of that portion of the spindle, that the strains of contraction are less than the limit of rupture of that portion, the remaining and major portion of the length of the spindle which for convenience I term the free portion of the spindle, having no projections that interlock with the mold to prevent free longitudinal contraction in the mold, of said free portion, when the cast metal of the spindle chills and cools in the mold. The free portion of the spindle may be tapered from larger to smaller size beginning at the ornamented end portion of the spindle where such ornamentation is used, since with a tapered spindle the ornamentation is placed on the larger end of the spindle to prevent possible interlock of the free portion of the spindle with the mold during cooling and contraction of the spindle;

or, if desired, where casting metal having a sulficiently high coefiicient of contraction is used, the spindle may have a straight free portion of uniform cross-section, since the lateral contraction of said free portion will separate it sufiiciently from the mold to permit free longitudinal contraction of said free portion in and relatively to the mold. Where no projecting and interlocking ornamentation is desired on the spindle, the free portion referred to, extends from end to end of and constitutes the entire spindle. event, the free portion referred to may have ornamentation formed thereon by the mold, that is uniform longitudinally of the spindle, or tapered from larger to smaller size towards the free end of the spindle, for example, longitudinal grooves or ribs.

In this manner, I find that I am able to successfully cast such hollow spindles in metal molds, and to so produce each spindle as a complete and unitary structure and of a length of from 30 to inches without rupture, or longer if desired, since the limiting length of tubes so cast is determined only by the length or distance that the casting metal will fiow in the mold; the finish and strength of such spindles are unimpaired, and said spindles may be successfully so cast by the slush method, which, briefly, consists of filling the mold with the molten metal, and then, when the cast metal adjacent the surface of the metal mold has chilled and set to a desired thickness of cast wall, discharging from the mold the metal within the chilled and set walls, that is still molten.

In accordance with and as a part of my present invention to facilitate casting long spindles of white metal I provide an improved form of mold as follows. The mold proper is made of metal, of separable parts longitudinally of the mold to permit removing the cast spindles therefrom, which mold at one end is provided with a bent or hookshaped tubular extension from the mold proper which projects upwardly when the mold is in use, and is sufiiciently high to accomplish the results below described, said projecting portion being open at its upper end. The other or straight end of the mold is also in open and free communication with atmosphere, but without offset or bend, and in line with the mold praper. The mold thus made, is provided between its ends, with a laterally extending, horizontal trunnion by which the mold is supported during its use. The mold is preferably provided with handles for manipulating it during the casting of the spindles.

In using the mold to carry out my improved process, it is first tilted on its trunnion, until its straight end is substantially above the level of the trunnion and its hook or oifset end is approximately at the same level as the trunnion. It is usually not essential that any exact angle of inclination be given the mold at this time, as long as it is in approximately the position described. The molten metal is then introduced into the offset end of the mold until it reaches substantially the upper end of the offset portion, the latter serving as a riser for the mold, and as a reservoir of molten metal to supply the remaining part of the mold with said metal as the casting operation is continued. Promptly after this is done, the mold is tilted on its trunnion to depress its straight end, first, until the straight end is substantially at the same level as the trunnion, and then by continued tilting, until the straight end of the mold is so far below the level of the trun- In any nion, that the remaining molten metal within the chilled and set walls of cast metal in the mold, flows freely out of the open straight end of the mold, leaving the tubular cast spindle in the mold. The mold is then opened, the cast spindle is removed, the mold is again closed, and the casting operation is repeated. The spindle and mold proper may have any desired form of crosssection and the mold may consist of any number of separable parts required to remove the castings from the mold; in practice, I find that it is usually suflicient to meet practical requirements, to make the mold in two parts separable along a vertical plane extending longitudinally and substantially through the axis of the mold, suitable clamping devices being employed to hold the mold parts together during casting operations, and to release said parts for separation to remove the cast spindles. Where the mold is somade in two separable parts, its trunnion is preferably secured to and extends laterally from one of said parts, and the mold handles preferably are secured to and extend laterally from the other of said mold parts, whereby said handles serve not only to tilt the mold on its trunnion during casting operations, but also to handle the removable part of the mold which becomes highly heated during repeated casting operations, leaving the other mold part in supported position on the mold trunnion, which facilitates removing the cast spindles therefrom.

In casting the spindles as described, the tilting of the mold causes the molten metal in the offset or reservoir portion of the mold, to flow into the straight portion of the mold to complete the free portion of the spindle casting, the rate of flow and the thickness of the spindle wall being determined by the rate of tilting the mold.

Where interlocking ornamentation is desired on one end portion of the cast spindle, it is preferably placed in the end portion of the mold proper, adjacent the offset or pouring end of the mold, to allow any desired interval of chilling before the tilting of the mold is begun, depending upon whether a different thickness of wall of cast metal is desired at the portion of the mold adjacent its pouring end, than throughout the free portion of the cast spindle, and, furthermore, a graded thickness of wall may be given the spindle, by changing the rate of tilting of the mold, as the casting operation progresses. In this manner, the thickness of wall of the cast spindle may be controlled throughout, to a nicety.

My invention also includes the improved tubular structures cast as described.

My invention will best be understood by reference to the accompanying drawings showing a preferred exemplification thereof, in which Fig. 1 illustrates in side elevation, a floor lamp assembly having a standard construction as above described,

Fig. 2 shows in side elevation, the spindle of the standard construction shown in Fig. 1, removed from the rest of the lamp construction,

Fig. 3 is a horizontal, sectional view to an enlarged scale, of the spindle shown in Fig. 2, taken along the line 33.

Fig. 4 shows in vertical, sectional view to an enlarged scale, the upper part of the standard construction illustrated in Fig. 1,

Fig. 5 shows in central, vertical, sectional view, a lamp standard embodying my invention, in which the parts thereof are secured together by a tie rod or tube, the central portion of the spindle and tie rod or tube being broken away and omitted, to more clearly show the remaining parts,

Fig. 6 illustrates in side elevation, a construction of mold adapted to produce spindles by my improved process, and

Fig. 7 is a left hand end elevation of the mold shown in Fig. 6, to an enlarged scale.

Similar numerals refer to similar throughout the several views.

As shown in Fig. 1, the floor lamp standard illustrated, consists of a base Ill, a spindle II, a head I2, and lamps and mountings therefor not specifically described, as they do not constitute a part of the present invention.

As shown in Fig. 2, the spindle II has threaded ends I la and I II) for engaging similar threads carried respectively by the base IE! and the head I2. As shown in Fig. 3, the spindle II is hollow to form a continuous tube to permit wiring connected with the lamps to extend through said spindle. It will be noted that no tie rod or tube is necessary to hold the parts together, since the spindle, which may, for example, be from 30 to 40 inches long, is a single, unitary structure extending from the base III to the head I2, to which parts it is securely connected to constitute a rigid standard. However, if desired, a tie rod or tube may be used with the spindle II, as below described.

The parts described are preferably cast of white metal in metal molds by the slush method, the long spindles being successfully so cast as unitary and integral structures, as below described.

As shown in Figs. 1 and 2, the spindle II may be provided at one of its end portions with laterally extending ornamental projections, located as shown in said figures at the lower end portion of said spindle, which may for a short length of said spindle, interlock with the mold in casting the spindle, restricting free contraction of the cast metal in the mold, but not to a degree to produce strains in the casting as great as the limit of rupture of the end portion of the spindle. The remaining or free portion of the spindle is free from such interlocking projections, and is of uniform or tapered cross-section, as desired, and where the latter is the case, as illustrated in Figs. 1 and 2, the cross-section of the tapered portion decreases in size progressively, until the end of the free portion of the spindle, which is its upper end as shown in Figs. 1 and 2, is reached;

Spindles constructed as described, may have ornamental projecting portions on their free portions, provided said projecting portions do not interlock with the mold to restrict free contraction in the mold of said free portions; for example, as shown in Figs. 1, 2 and 3, for the spindle II, the free portion of the spindle may have formed thereon spaced and longitudinally extending ribs I I0, and intermediate and longitudinally extending smaller ribs I Id.

In Fig. 4, the head I2 is shown as extended downwardly at I211. and internally threaded to engage the threads I In by which the head is supported. In this view is also shown threaded into the head I2, a vertically extending support I3 carrying the central and vertically disposed lamp socket I4 of the floor lamp.

In Fig. 5, I show an assembly of parts similar to that shown in Figs. 1 and 4, excepting that the parts, including a spindle II made as above described, are secured together by a tie tube I6 extending through said parts, having threaded ends parts provided with nuts I! and engaging washers I8 and I9 which respectively press against the head I2 and the base I0. In this case, the socket I4 is shown as mounted on the upper end of the tube I6, and the head I2 includes as a supporting means, an intermediate short tubular member I5 of cast metal, resting upon the spindle I I.

In Fig. 6, I illustrate my improved mold, constituting a part of the present invention, at 2I, said mold having a laterally extending trunnion 22 mounted for turning movement in a support 23, to hold the mold in desired position. The mold as illustrated in Figs. 6 and 7, consists of two separate parts 2Ib and Zlc engaging each other in a vertical plane extending substantially through the longitudinal axis of the mold. The trunnion 22 extends from the part 2Ic, and the part ZIb is provided with handles 24 and 25 extending laterally therefrom to control the mold during casting operations, and to handle the part 2Ib when it is removed from the part 2Ic. The mold is provided with clamping devices for holding the parts of the mold together, each of said devices, as more clearly shown in Fig. 7, consisting of a lug 28 extending from the part Ho and pivotally supporting at 21, one end of a screw 26 provided with a wing nut 29 to engage a lug 30 extending from the part 2 lb, so that by tightening the wing nuts against the lugs 30, the parts 2Ib and 2Ic are securely clamped together, and by releasing said wing nuts, the screws 26 may be swung clear of the lugs 30, and the part 2Ib' may then be removed from the part ZIc. It will be understood that the clamp-ing devices shown, are illustrative only, and that any equivalent clamping devices may be employed, that will secure similar results.

As shown in Fig. 6, the right hand end portion of the mold 2|, is provided with an upwardly extending offset or hook portion 2 Ia, which is hollow and in communication with the mold proper, and open at its upper end to receive the molten metal poured into the mold. As indicated in Fig. '7, the mold is open to atmosphere at its other or straight end.

In using the mold 2 I, it is tilted on the trunnion 22 to approximately the position shown in full lines at A in Fig. 6, in which position the molten metal is poured into the open end of the offset portion 2 la until it is substantially filled, the straight end of the mold being at this time sufiiciently raised to prevent the flow from it of the molten metal. The mold is then tilted on its trunnion 22 to the position indicated at B, causing the molten metal in the mold to flow through the straight end portion of the mold to complete the casting of the tubular casting in the mold, and the tilting of the mold is continued until it reaches its draining position, for example, as indicated at C in Fig. 6, for which position the molten metal still within the chilled and set tubular wall of the casting, flows freely from the casing and out from the straight end of the mold.

The mold 2I contains a mold proper which is the counterpart of the tubular structure to be cast in the mold, and where laterally extending and interlocking projections or ornamental parts are desired on but one end portion of said cast tubular structure, they may to advantage be located at the end of the mold adjacent to the ofiset portion 2Ia, to facilitate producing the thickness of cast tubular wall desired at that location, the thickness of the cast tubular wall throughout the mold, being determine-d by the rate of tilting of the mold after the molten metal is poured into the offset portion, the latter serving as a riser or reservoir to supply the straight portion of the mold with molten metal, to progressively cast the tubular structure therein when the mold is tilted as described.

It will be understood that while the mold described is well adapted to produce hollow spindles of the type shown in Figs. 1 and 2, it may also be used effectively in casting tubular structures generally, whether they have free portions or not, and that this is particularly the case where the slush method of casting described, is employed.

In the manner described, I am able to cast in rigid molds, long tubular structures from metal having a large coefficient of contraction, meaning by the term long in this connection, a length approximately equal to times the external diameter of the tubular structure, or of greater length, the greater limit of said length being determined only by the distance the molten metal can be caused to flow in the mold.

From the above it will appear that I provide a process for successfully casting long tubular structures in rigid molds, that is particularly applicable where the cast metal has a large coefiicient of contraction, and that is particularly adapted to the casting of such structures having long end portions that are free from projecting and mold-interlocking parts, and that my invention includes the cast metal structures so made, as well as the process of making said structures, and the improved mold employed in carrying out said process.

In my copending application filed of even date herewith, I disclose an improved process for making spindles for lamp standards and the like, and products thereof, by restraining the spindles from contracting longitudinally in the molds in which they are made, and distributing the resulting strains in the cast spindles to prevent rupturing them, which I do not claim specifically in the present application.

While I have described my invention in the particular manner exemplified, I do not limit myself specifically thereto in carrying out my invention, as I may employ equivalents of the steps of treatment described, and produce and employ structures which are the equivalents of those described, without departing from the scope of the appended claims.

What I claim is:

1. The process of making long tubular slush cast metal structures in a rigid mold open at both of its ends, consisting of introducing the molten metal into one end of the mold with the latter in a position prevent-ing free flow of the molten metal through the mold, and then progressively casting the remainder of the cast structure by flowing the molten metal therethrough, and then discharging the remaining molten metal from the other end of the mold.

2. The process of making long tubular slush cast metal structures in a rigid mold open at both of its ends, consisting of introducing the molten metal into one end of the mold with the latter in a position preventing free flow of the molten metal through the mold, and then progressively casting the remainder of the cast structure by flowing the molten metal therethrough at a rate determining the thickness of wall of the cast structure, and then discharging the remaining molten metal from the other end of the mold.

3. The process of making long tubular slush cast metal structures in a rigid mold open at both of its ends, consisting of introducing the molten metal into one end of the mold, flowing the molten metal through the mold to progressively form a cast tubular structure thereof along the surface of the mold, and discharging the remaining molten metal from the other end of the mold.

4. The process of making long tubular slush cast metal structures in a rigid mold open at both of its ends, consisting of introducing the molten metal into one end of the mold, flowing the molten metal through the mold to progressively form a cast tubular structure thereof along the surface of the mold, controlling the rate of flow through the mold to produce a desired thickness of wall of the cast tubular structure, and discharging the remaining molten metal from the other end of the mold.

5. The process of making l-ong tubular slush cast metal structures in a rigid mold open at both of its ends, consisting of introducing the molten metal into one end of the mold, flowing the molten metal through the mold to progressively form a cast tubular structure thereof along the surface of the mold, and discharging the remaining molten metal from the other end of the mold, and permitting the cast tubular structure to contract freely longitudinally of the mold.

6. The process of making long unitary and tubular cast metal spindles adapted for use as lamp standards and other purposes requiring long, slender, tubular structures, consisting of introducing molten metal having a large coeflicient of contraction into one end of a mold having at one end portion a casting interlocking conformation and thereby partly filling the mold, and then progressively flowing the molten metal through the mold and chilling and setting said metal against the mold and discharging from the other end of the mold the still molten metal within the chilled tubular cast-metal wall, said casting excepting at said end portion being free from longitudinal restraint in the mold, whereby the tubular cast-metal structure contracts freely in the mold and rupturing strains therein are avoided.

7. The process of slush casting long unitary and tubular structures of white metal having a high coeflicient of contraction, consisting of first chilling and setting one end portion or" the cast structure having interlocking engagement with the mold, and then progressively forming, chilling and setting successive parts of the remaining portion of the cast structure unrestrained against contraction, whereby rupturing strains in the cast tubular structure are avoided.

8. A long slender tubular and unitary metal structure suitable for lamp spindles and the like, consisting of a slush. casting of white metal having a large coefiicient of contraction, said casting having mold interlocking projections on one of its end portions and being otherwise free from' such projections whereby said casting contracted lengthwise in the mold without rupture. I

9. The process of making long unitary and tubular cast metal spindles by the slush method of casting, consisting of introducing molten white metal into one end of a mold to progressively produce a chilled and set tubular wall of cast metal, and discharging the remaining molten metal in the casting out from the other end thereof.

ALLAN H. BELL-

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