US2969614A - Charge forming apparatus - Google Patents

Description

1, 1951 A. H. STEWART 2,969,614

CHARGE FORMING APPARATUS Filed May 4, 1956 2 Sheets-Sheet 1 /9a JF'IG. Z 42 44 INVENTOR. a ANDREW/i STEWA R 7' 'L hcW' M 1961 A. H. STEWART 2,969,614

CHARGE FORMING APPARATUS Filed May 4, 1956 2 Sheets-Sheet 2 INVENTOR. Awake-W16! STE/444R 7' HIS A TTORNEVS.

'and article-forming temperatures. 'particularly to these matters from the standpoint of the United States Patent CHARGE FORMING APPARATUS Andrew H. Stewart, Windy Ghoul, Beaver, Pa. Filed May 4, 1956, Ser. No. 582,867

2 Claims. (Cl. 49--55) This invention deals with the providing of charges in a formable state or to the controlled feeding of them, employing a molten vitreous or plastic type of material. The invention particularly relates to the forming of rela- "tively large size charges or gobs and at a desired timed interval without spoiling the charge from the standpoint of its formability.

. Ihave previously set forth some of the difiiculties which are present in feeding charges of larger size and at a slower rate than usual practice. In recent work in this particular field, I have found that important controlling factors in successfully providing a large gob, such as may be used in making a large pressed lighting fixture bowl or street lighting globe, arise out of the change in viscosity of .the plastic or vitreous material as caused by time delays and a cooling ambient atmosphere, by reason of diiferent thicknesses of the material along its extent or body, and may also arise from the forming of layers of the material within a particular charge or gob. Cords, seeds, folds, striations, laps, bubbles and other imperfections are to be avoided in a charge or gob if it is to produce a satisfactory quality product as formed.

' My present invention deals particularly with the above problem and with means for providing the charge material with proper holding, gob feeding and forming, severing The problem applies forehearth or boot of the furnace for supplying the molten material.

'a charge of molten material that is to be formed into an article while in a molten condition; A still further object of my invention has been to devise improved control apparatus for feeding charges or gobs of molten material;

These and many other objects of my invention will appear to those skilled in the art from the illustrated embodiment and the description as set forth herein.

In the drawings: Figure 1 is a side view in elevation and partial section of apparatus employed in accordance with my invention;

it shows feed control means at or approaching its extreme lower or down feed position and prior to or just before the start of its return or reverse movement;

.Figure 2 is a somewhat fragmental side section in elevation of the apparatus of and on the scale of Figure 1;

this figure illustrates another feeding position of the feed control means wherein such means has started its return or upward movement and is efiecting a slight attenuation of the neck of a suspended charge by reason of a slight withdrawal of molten material upwardly within a feed orifice;

Figure 3 is a view on the scale of and similar to Figure 2, but showing the feed control means in an intermediate upper position between the positions of Figures 2 and 4, and further illustrates the severing of a formed charge and the reception of the charge within an articleforming mold;

Figure 4 is a side section in elevation on the same scale as Figures 2 and 3, illustrating the attainment of a. maximum upward position of the feed-control means and the filling of the feed orifice which may follow from holding the control means in the position of Figure 4 or from an immediate reversal to start the movement of the control means vertically-downwardly toward the feed orifice; and

Figure 5 is a fragmental side section in elevation on the scale of Figures 1 to 4, inclusive, illustrating a position of the feed control means intermediate the positions of Figures 4 and 1, and further illustrating the downward or forward strokeof the control means as employed in forming a charge or gob; this figure also shows a slightly modified construction wherein a larger annular space is provided about the bottom portion of the control means.

In carrying out my invention, I employ a somewhat conventional forehearth, feeder boot or channel 10 which defines an upper or normal supply chamber A for the molten material contained therein. I provide the forehearth with a relatively large size or diameter of discharge or feed opening through its floor portion. The forehearth 10 thus provides an upper, primary holding and primary delivery chamber A for the molten material that is to be formed as a charge, and that is to be delivered to a suitable article-shaping means.

Also, in accordance with my invention, molten material or glass is fed in a controlled manner from the discharge opening or orifice of the primary chamber A into a lower, secondary or feed chamber A (A" of Figure 5) of greater depth, but of lesser effective diameter or width. A suitable feed control means, such as a plunger 35, is operatively mounted for reciprocation from the upper chamber A downwardly through its feed opening, and along the lower feeding, gob or charge-forming chamber A. It will be noted that the control means 35 is positioned and operates in alignment with discharge or feed orifices. The molten material within the lower chamber A is surrounded by a heating chamber B to supplement the heat retained from the melting operation and to offset heat losses incident to the flow of the material into and in the retention of the material within the secondary chamber A.

As shown particularly in Figure 1 of the drawings, the molten material may be discharged and formed as a gob or charge C, beneath the feed orifice of the secondary chamber A, and at the best effective temperature or attendant viscosity for the type of material involved, as well as with uniformity of texture, and without seeds, air bubbles, and stratification. The lower chamber A, as shown in the illustrated embodiments of my invention, cooperates with the plunger 35 to provide, discharge, and shape a charge or gob C of the desired size and characteristics.

Employing the principles of my invention makes it possible to provide any desired, relatively large size of gob or charge, at a suitable timed interval between charges, of a proper and most effective temperature or viscosity, and without defects in its uniformity, characteristics, etc.

Referring particularly to the drawings, I have shown a forehearth, boot or feed channel for formable molten material, such as glass or plastic, as provided by a refractory enclosure 10. This enclosure has a feed opening directly into the lower or secondary chamber A.

or portion a in its bottom wall which is of relatively wide extent and of such greater extent or diameter than in ordinary feed opening, to supply the molten material The lower feed chamber is defined by .an extension sleeve or hollow refractory wall member 11. The member 11 has an upper mounting flange portion 11a which is held in position about and in alignment with the feed portion 10a of the forehearth 10 by a metal mounting ring 12 of angular section. The ring 12 engages or fits over the flange portion 11a and holds the member 11 in a suspended position beneath the forehearth 10.

It will be noted that the mounting ring 12 is secured, as .by weld metal, to a metalwall or enclosure member 13. An outer and upper fiangeportion 13a is secured or suspended in position from an under-carriage or frame 14 of the apparatus and particularly, from horizontal or transverse portions 14a thereof. A bottom feed or orifice ring 15 is positioned about the open bottom end portion of the member 11 and upon its bottom lip edges by a .bottom-positioning or support ring 16 of metal having an angleshape section. Bolt and nut assemblies 17 may, as

.shown, be employed to removably secure the support ring 16 to a bottom or floor portion of the enclosure member 13.

It will be apparent that the walls, including'the cylindrical side wall of the enclosure member 13 defines a heating chamber substantially along the full depth or vertical extent of the inwardly-positioned refractory wall member 11. Heat may be supplied to the heating chamber B by a burner unit 24 see particularly Figure l of the drawings. The burner unit 20 may be of conventional construction, but is shown provided with an inner gassupply throat 20a, a surrounding and outer air-supply throat or passageway 29b, and supply lines or pipes 21a and 21b for connecting the respective chambers 20a and 20b to suitable sources of gas and air. It will be noted that a control and shut-off valve is shown mounted in the gas supply line or conduit 21a.

I have somewhat diagrammatically illustrated a cooperating pair of shear blades 18 beneath the orifice defined by the ring 15 to sever a formed charge or gob C of the material. The gob is thus delivered directly to a suitable article-shaping mold or (as shown in Figure 3) indirectly through the agency of an inclined chute 55. As shown particularly in Figure 1, the under-frame 14 cooperates with and is secured to a side and overhead support frame structure 19.

To facilitate providing a uniformity of texture of the material, I have shown an agitator sleeve or tube 22 of refractory material, as depending through a top opening 1% in the furnace forehearth 10. The sleeve or tube member 22 is adapted to project depthwise for substantially the full level of the molten material within the chamber A and, at its upper end, has an enlarged bearing-mount, banding and top closure portion 22a. The portion 22a is journaled within a Timken bearing 29 to take both axial and radial loads under rotative movement. A relatively large chain sprocket 23 is secured to the portion 22a and rotates it through a chain 24 and a relatively smaller sprocket 25. Thus, the unit or assembly 23, 24 and 25 serves as a speed reduction unit for driving the sleeve 22 at a relatively low stirring or agitating speed.

The smaller sprocket 25 is secured on a shaft'26a of a .geanreduction unit 26 which, with reversible electric drive motor 27, is bolted to a support wing member 28. The wing member 28 has a forwardly-horizontally projecting arm portion 28a which carries the bearing 29 and has a vertically-mounted split-sleeve clamp 39. The clamp 30 is carried by the support member 28'to adjustably receive a vertical support rod 32. A threaded thumb screw 31 is threaded between split portions of the clamp 30 to grip the rod 32 at a desired vertical positioning of it in the clamp 30. The lower end portion of the rod 32 is secured by a cross pin 33 to a mounting collar 34. As shown in Figure l, the collar 34 may be secured to project from the under-frame 14.

The depending, rotating sleeve or tube 22 and its complete driving assembly may thus be vertically ad usted on the rod 32 to a proper operating relationship with respect to the molten material within the chamber A of the forehearth 10.

A feed control plunger '35, shown of substantially cylindrical shape, is operatively suspended through the feed opening ltlb in the forehearth 10 and within the chambers A and A. The lower end of the plunger 35 is shown as having a bulbous knob portion 35a to enter the orifice defined by the ring 15 and further the chargefeeding and controlling operation. The plunger 35, as shown, has an enlarged top end or piston-like portion 35b that is adapted to operate or reciprocate within the tube or sleeve 22. A support and drive rod 36 projects upwardly from the portion 35b and through a sleeve bearing 37 that is carried by the portion 22a of the sleeve and that journals the rod 36 for vertical movement therein. A horizontally-projecting side arm 39 that is secured to the framework 19 carries a collar 38 which also slidably receives the drive rod 36, and in a spaced relationship above the sleeve bearing 37.

A cross pin 41 is secured to project from the rod 36 at its upper end portion, and to be slidably received within a bifurcated or forked portion 42a of a cam-actuated swing arm 42. The arm 42, at its other end, is pivoted by a pivot pin mounting assembly 43. The latter is secured on a vertical slide block 44 which is mounted for vertical adjustment within a slotted portion of an upper mount part 19a of the frame structure 19. The slide block 44 may be secured in an adjusted position by a set 'screw 44:: which projects through the mount portion 19a and engages the slide block 44, see Figure 1.

The arm 42 is provided substantially centrally along its length with a downwardly-projecting under-cam face or rider portion 42b that operates in engagement with a properly shaped peripheral edge of a timer cam 45. A weight 40 that is mounted on the operating end of the arm 42, maintains edges of the cam 45 in engagement with the cam portion 42b, and provides a more positive down action of the plunger 35, as supplemented by the effect of the weight .40 on the plunger and its assembly. The shape of the cam 35 may be varied to produce any desired type of reciprocation of the plunger 35. However, the shape shown has been employed as practical in producing relatively large size gobs at a relatively slow rate of two to three a minute.

The cam 45 is secured on a cross drive shaft 46. As shown particularly in Figures 1 and 2, a beveled gear 47 on the shaft 46 meshes with a beveled gear 48 on a longitudinal drive shaft 49. The shaft 49 is carried in a *stand 50 and has a sprocket 51 secured on its outer end to drive it through chain 52, a smaller motor sprocket 53, and an electric motor 54. The drive arrangement of the sprockets 51 and 53 shown is such as to produce a reduction of speed and increase 'in power as to rotative movement provided by the motor 54, and made effective in the rotation of the cam 45.

In the drawings, Figure 1 shows the plunger 35 at or .near its final down position. It will be noted that at this time, the plunger '35 defines a downwardly-converging spacing from the feed orifice 10a, as effected in co operation with the inner face of a downwardly-inwardly sloped or converging cone-shaped Wall 11b of the mem- .ber 11.

The portion 11b terminates somewhat intermediate the depth of the member 11 and is joined to the vinner face of a substantially cylindrical, lower wall portion 11c. It will be noted that the portion defines a substantially narrow cylindrical material-receiving cross-area with the plunger 35.

plunger. Since the molten material cannot initially readily and speedily flow between the plunger 35 and the sleeve wall member 11, due to the narrowness of the spacing at 11c, and the friction of the material adhering to the plunger, the 'void is at least partially filled by withdrawing the material back from or through the orifice of the ring 15. t

The effect of the initial upward pull of the means 35 is illustrated in Figure 2. That is, since the weight of the gob or charge C is still being pulled vertically-downwardly by gravity, the net effect of withdrawing some of the material back through the orifice, is to neck or narrow the charge, just below the orifice, and preliminary to the severing or shearing-01f operation as effected by closing the pair of blades 18, see Figure 3. The charge C may fall vertically (as shown in Figure 3) into the feed chute 55 that leads to an article-forming mold, and while the cut-off stub D is being drawn backwardly and, in some cases, through the feed orifice.

I, however, prefer to design the apparatus so as to stop the draw-back of the stub D, so that it does not go upwardly beyond the opening or orifice of the ring 15. This assures the elimination of air bubbles in a subsequently discharged gob. That is, there is a tendency to trap air when the glass or molten material is drawn too far or upwardly beyond the feed orifice. The speed of withdrawal is also an important factor in this connection and I prefer a relatively slow speed, so that the voids may be properly filled by the moten material rather than by an extraneous agent.

The clearance between the member 11 and the plunger 35 may be varied by changing the diameter of the member 11 or of the plunger 35. A tighter or closer clearance area or spacing may be employed to provide for a smaller size gob or a slower timing of gob formation (see the chamber A' of Figures 1 to 4), and a larger clearance area or spacing may be provided for a faster or larger size of gob formation (see the chamber A" of Figure 5.) Also, in forming larger gobs or charges, a larger plunger is preferably used with, of course, a correspondingly greater size of sleeve. The stroke of the plunger may also be varied to provide a longer stroke or shorter stroke, depending on the size of the charge required. The shorter stroke, of course, is employed for a smaller charge.

In raising the plunger 35, I find that it should, as previously intimated, be raised rather slowly, at least until it reaches a position between Figures 3 and 4. This is done to increase the feeding interval and to accommodate the fill-up of the material downwardly from the forehearth 10, and between the plunger and the member 11 within the lower chamber A. However, I found that it is necessary to gradually increase the rate of upward movement as the plunger 35 moves towards its exit from the sleeve wall member 11. This is due to the gradually more rapid flow of the material into the chamber A, due to the constantly decreasing frictional area between the plunger and the sleeve.

Once the plunger 35 has left the sleeve member 11, the material readily flows by gravity towards the lower or outer feed orifice and a new gob C or charge may start to form, see Figure 4. At this time, the upward movement of the plunger is greatly increased and its downward course is effected to force the material through the orifice of the ring 15 to stuff the charge or gob to the size or shape required. The shape of the cam 45 imparts the desired speed to the downward movement of the plunger to provide the size and shape of gob C as required.

It may be noted that the member 11 may be of cylindrical form, but is preferably flared-outwardly towards its top end and away from the plunger 35. If desired, the plunger 35 may be tapered to conform somewhat to the shape or flaring of the member 11. There are considered instances where it is not necessary to draw the plunger completely out of the memberll. 'The plunger 35 may have a smooth orrough surface texture and may be solid or tubular. It may also be made with a short cylindrical. section on its bottom, instead of the knob 35a, without departing from the spirit and scope of the invention. ,7 V r The upward movement of the plunger or plug 35 is important, especially from a down position (such as shown in Figure l) to an up position wherein its lower end has cleared the smaller diameter or lower wall portion (see Figure 4). When the plunger 35 is moving away from theorifice 15, along the narrow chamber defined by the wall portion 11c, I operate at a rate to provide a proper balance (as effected by suction) between down pull of the molten material and up pull of the stub of material that is adjacent to or within the orifice 15. Ordinarily the down pull is to be the predominating action. Both a slower rate and a larger spacing provide a greater elfectiveness of the so-called down pull. In the construction here involved, gravity alone will not make the feeding apparatus work properly. In accordance with my invention, gravity is overcome during the retarding period.

During the feed period, the material is removed from the orifice at a rate faster than gravity alone can replace it; initial replacement may be accomplished by a positive down movement of the plunger. It will be noted that control of the material is accomplished without relying basically on adhesion of the material to adjacent surfaces, such as of the plunger 35.

The material is pulled downwardly into the narrow part of the chamber A to fill up the under-area of the plunger end during its upward movement and the orifice stub of material is held in position, both by suction of the plunger or plug 35. The material is not free flowing within the chamber defined by the wall 110 and during the period the plunger 35 defines a restricted annular or cylindrical passageway or chamber therewith.

My invention may be employed with either a so-called deep boot or shallow boot or forehearth channel. In the former type, if the rate of feed is to be somewhat faster, the enclosure or oven chamber B may be eliminated and an orifice-heating annulus or ring heating unit (gas or electric) may be used. In any event, the molten vitreous or plastic material that is to be feed-formed as a charge should be maintained at an elevated temperature conducive to the steps involved.

What I claim is:

1. In a feeder apparatus for hot plastic or vitreous material having a forehearth and a support frame to supply molten material downwardly in the form of gob charges therefrom, and a plunger projecting downwardly through an opening in the top of said forehearth to control the shaping and delivery of the gob charges from said forehearth, means for providing a uniformity of texture of the molten material which is discharged from said forehearth, said means comprising a rotatable refractory agitator sleeve operatively projecting downdownwardly through the opening in the top of said forehearth, said sleeve extending circumferentially about said plunger and into the molten material within the forehearth, an L-shaped cantilever support wing connected to one side of the support frame and projecting over and along the top of said forehearth, a bearing carried in said support wing co-axially above said plunger to rotatably suspend said refractory sleeve about said plunger, a. motor mounted on said support wing and operatively connected to said sleeve to impart rotational movement thereto, and connecting means on said support frame for vertically-adjusting said support wing to simultaneously adjust the vertical positioning of said sleeve and said motor with respect to said forehearth so that power from said motor may be continuously supplied to said sleeve to continuously rotate said sleeve during the positioning and at all desired vertical posia swing arm having means at one end operatively engaging said drive rod to vertically reciprocate said rod and said plunger, apivot mounting assembly securedto the other side ofsaid support frame, the other end of said swing arm swingably secured to said pivot mounting assembly for pivotable movement with respect thereto, an actuating cam mechanism operatively positioned on-saidsupport frame and engaging an intermediate portion of said swing arm to actuate it in a timed relationship to reciprocate said plunger, means for vertically adjusting said pivot mounting assembly to selectively adjust the height of reciprocation of said plunger, and weight .meanson said swing arm to maintain said swing arm inoperable engagement with said cam mechanism andprovide a positive down action of constant magnitude .0]: said plunger for controlling gob formation.

2. In a feeder apparatus as defined in claim 1 where- "inQa second motor is mounted on said supportframe and 8 pperatively connected to said actuating cam mechanism for driving said cam mechanism independently of the rotation of said agitator sleeve.

References Cited in the file .of this patent UNITED STATES PATENTS 1,564,909 Steimer Dec. 8, 1925 1,582,725 Bethel et al. Apr. 27, 1926 1,717,802 Miller r June 18, 1929 1,810,736 'Soubier .7..... June 16, 1931 1,825,416 Owens Sept. 29, 1931 1,828,442 Rank-in Oct. 20, 1931 1,828,443 Rankin Oct. 20, 1931 1,830,849 Miller Nov. 10, 1931 1,843,248 'SoubierJ, ..Feb. 2, 1932 1,934,811 Miller Nov. 14, 1933 2,305,739 Shackelford Dec. 22, ,1942 2,470,558 Honiss May 17, 1949

Images