US3029482A - Mold conveying system - Google Patents

Description

April 17, 1962 J. M. BURNETT MOLD CONVEYING SYSTEM 3 Sheets-Sheet i Filed March 30, 1959 INVENTOR. JOEL M. BURNETT NN @ml/J,

QM n., mw QN April 17, 1962 J. M. BURNETT 3,029,482

' MOLD CONVEYING SYSTEM Filed March 30, 1959 A 5 Sheets-Sheet 2 April' 17, 1962 J. M. BURNETT 3,029,482

MOLD CONVEYING SYSTEM Filed March 30, 1959 5 Sheets-Sheet 3 JOEL M. BURNETT BY l 03mm, FP

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ates

Patented Apr. 17, 1962 3,029,482 MLD CONVEYING SYSTEM v Joel M. Burnett, Chagrin Falls, hio, assigner, by mesu assignments, to Bartlett-Snow-Pacilic, inc., a corporation of California Filed Mar. 30, 1959, Ser. No. 802,769 16 Claims. (Cl. f2.2-4.0)

rIhis invention relates to an improved method of han# dling molds in a closed molding system and to apparatus for the practice of such method.

The closed loop type of foundry system is of course old and widely used and is basically comprised of a continuous conveyor which defines the loop and, distributed therealong, the various machines and devices needed for molding in flasks carried by the conveyor. The conventional distribution of this appurtenant equipment is such that the loop is, in effect, divided into a set-out zone in which either a closed mold is placed on the conveyor or the cope and drag deposited for assembly while on the conveyor, a pouring zone in which the molten metal for the castings is poured into the closed molds, a cooling zone for setting of the metal, and a removal zone where the molds are transferred to a shakeout machine for separation of the castings and return of the molds to the molding machine which serves the set-out zone. Each mold on the conveyor in such a system travels from the point of set-out successively through these zones in the order indicated to the removal point, and the cooling required must take place between the pouring zone and the shakeout; the time for cooling is thus conventionally determined by the speed of the conveyor and the aforesaid distance over which the casting is carried.

lt is a primary object of my invention to improve such a system by substantially increasing the cooling time, without, as would normally be expected, increasing the over-all length of the usual closed loop or requiring the conveyor speed to be reduced.

Briefly, such improvement is realized by providing at least two laterally spaced lines of molds about the loop, performing the set-out and pouring functions in one such line and the removal for shakeout in the other line, and appropriately shifting the molds from one `line to the other so that each mold moves, without interference, in an overlapping path or distance greater than the actual length of the conveyor. In the preferred embodiment of the invention to be described hereinbelow, two such mold lines are provided, the mold set-out and pouring are accomplished in the outer line, the molds are shifted from the outer to the inner line just in advance of the set-out station, and the molds are removed from the inner line at the side of the loop opposite that at which they were set out. Such handling will readily be seen substantially to increase the cooling time as compared to a conventional system occupying the same space, with, the new arrangement actually serving the purpose of a system twice as long in this preferred embodiment and the effect even further increased should more than two mold lines be used. Y

It will be further seen that this mold handling method provides high rates of production even where space is limited, high molding rates usually requiring higher conveyor speeds, longer cooling times, and usually longer pouring zones. That is, as compared to a conventional foundry system of given size or area, the same space can be utilized in accordance with the invention to provide higher rates of production or the same rate of production as before can be realized in much less space than previously used. Y

The lateral arrangement and shifting of the molds as discussed provides an additional advantage when mold weights are employed, since a poured mold with the 2 weight thereon will be alongside each newly set-out mold and the weight easily transferred from the former to the latter. Special weight conveyors are therefore unnecessary, and it is no longer required to transfer the weights longitudinally'from one point to another on the loop.

It is also an object of my invention to provide mold handling apparatus operative to transport molds in the manner indicated, including such lateral shifting of the same.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features herein after fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. l is a partially broken and somewhat simplied top plan view of a molding system in accordance with the present invention;

FIG. 2 is a vertical section as viewed from the plane of the line 2- 2 in FIG. l;

FIG. 3 is another vertical section of the system taken in the plane of the line 3-3 in FIG. l;

FIGS. 4 and 5 are further vertical sections the planes of which are indicated respectively by the lines 4-4 andv 5 5 in FIG. 1.

Referring now to the drawings in detail, the illustrated embodiment of the invention comprises a continuous car type mold conveyor 10 arranged in a loop having straightl parallel sides and semi-circular ends. Each car platform 11 is of a width to accommodate two of the molds 12 to be handled in side-by-side relation with respect to the longitudinal axis of the conveyor, with the platforms shown being of a length each to support two outer and two inner molds.

The car platforms 11 are of the configuration shown and articulated for passage about the curved ends of the loop, with the undercarriage of the conveyor including wheels 13, which ride on rails 14, and a universal type of chain 15 which is driven by appropriate power means, not shown. As indicated earlier, the construction of such conveyor, and the drive therefor as well, are known and commercially available, such equipment being regularly supplied, for example, by The C. O. Bartlett & Snow Co. of Cleveland, Ohio, the assignee of this application. It will also be understood that the conveyor details are not per se important in the present invention, and any known type of closed mold conveyor can be used as long as the same will accommodate at least'inner and outer lines of molds.

The molding machine located within the loop and designated by reference numeral 16 is likewise conventional,

and a roller conveyor 17 extends substantially horizontally therefrom at an elevation higher than the conveyor 1G,

with its outer end approximately at the longitudinal center of the conveyor near one end of a straight side section of the same. The cope and drag molds formed in the machine are moved by the machine operator along this conveyor 17, and another operatory standing at the out! side `of the car conveyor 10 takes each drag, places the same on the adjacent, outer half lof a mold car therebeneath and closes the mold with the cope.

The conveyor moves counter-clockwise as viewed in FIG. l, and as the cars advance in such direction, they are of course loaded in the same manner to form an outer line of molds. To assist the setting out of the molds, a vertical guide 18 depends from the end of the mold-supplying conveyor 17 and extends along the centerline of the conveyor l0, with its bottom edge fairly close to the top of the latter, thereby marking the division for the outer and inner mold lines.

Mold weights 19 are used in this illustrated embodiment and, for the moment, it will be simply noted that such a weight is placed on each closed mold at this setout station.

The pouring zone in this system may extend over the area from the dashed line 20 about the conveyor in the direction of its advance to the further dashed line 21, with the molten metal 'being poured into the closed and weighted molds in the outer line of the conveyor 10 over such section thereof. It is not necessary for full and proper understanding of the present improvements to illustrate particular structure for the molten metal handling and pouring, since any suitable apparatus of this nature may be employed, but it will be seen that the zone for pouring is of substantialy length in relation to the over-all size of the loop.

The poured molds on the conveyor 10 in the outer line thereof move around the other end of the loop, the right end in FIG. 1, and encounter a lateral transfer station designated generally by reference numeral 22 at which they are shifted individually transversely from the outer line to corresponding positions on the inner half of the conveyor, thereby to form the inner mold line. The mechanism here illustrated for such shifting comprises a vertical pusher plate 23 arranged alongside the conveyor 1G, with its bottom edge slightly above the top of the conveyor to clear the same and the area of this plate preferably being somewhat larger than the side area of the closed mold 12. Such plate 23 is reciprocably supported by means of two rods 24 secured to the outer side of the same and slidably passing through stationary guiding and supporting sleeve members 25. A fluid-actuated piston cylinder assembly 26, with its piston rod 27 secured centrally to the outer face of the plate, provides the desired controlled reciprocation of Such plate, and a stop 28 is disposed at the inside of the conveyor 1G in opposition to the pusher plate 23.

Accordingly, as each closed and poured mold 12 in the outer line moves alongside the normally retracted pusher plate 23, the latter is actuated through appropriate control of its drive cylinder 26 to advance against the mold to push the same from the outer to the inner half of its conveyor car, with the inner stop 2S of course limiting such shifting of the mold.

The poured molds now continue to advance in the inner line of the mold conveyor through the set-out zone, behind the guide 18. As each of these molds passes beyond the forward end of such guide, the operator shifts the weight .1.9 thereon to the newly set-out mold now outside the former, this transfer requiring only a small lateral and easily accomplished movement of the weight. The first considered molds, now disposed in the inner line, advance along the loop through the pouring zone, in which the new molds of the outer line receive the molten metal, to a removal point indicated generally by reference numeral 29 at the other side of the loop.

At this removal point, each inner mold is intercepted by a pair of curved plows 30 which direct the same inwardly, olf the conveyor car and onto a line of power driven rolls 31. The plows extend over the conveyor 10, while such rolls commence beneath the inner peripheral edge of the conveyor. Such take-ott arrangement will be seen to utilize the power of the mold conveyor as the initial motivating force for removal, the frictional drag being sufficient to turn the molds and start them onto the power driven rolls 31.

With particular reference to FIG. 2, in which the mold conveyor 10 has for convenience been turned to be perpendicular to the plane of this section, the power driven rolls 31 advance each poured, and now cooled, mold angularly inwardly in the same general direction to vibrating shakeout rails 32 oi conventional type, and the mold advance is taken over by a shakeout mold puller 33 which is reciprocated by a fluid-actuated piston cylinder assembly 34. This mold puller, which is not shown in FIG. l since it would unduly obscure the illustration of the latter, is guided on rails 55 and has a depending pivoted arm 36 which can swing out of the way to clear the mold as the puller approaches and moves over the samej` when the puller clears the mold, the arm swings down to a vertical stop position to engage behind the mold for pulling in the manner indicated by comparision of the full and dasher line representations of the mold puller in FIG. 2. Such puller guides each mold across the shakeout rails and deposits the same on an inclined roll conveyor 37.

The contents of the llaslf. are of course dropped by the shakeout operation and fall to a vibrating shakeout conveyor 38 which extends along beneath the power driven rolls 21, the shakeout rails 32, and a portion of the roll conveyor 37. Such shakeout conveyor has a grid or partially opened oor portion, as indicated at 39 in FIG. l, through which the sand from the asli falls into a hopper 46, while the casting continues to the end of the shakeout conveyor and falls therefrom into a liquid-containing castings cooling tank 41. The castings are picked up in such tank by a conveyor 42 and carried thereby across the mold conveyor 10 in upwardly spaced relation to a delivery point 43 outside the latter.

Each now empty mold flask moving along the roll conveyor 37 from the shakeout is transferred to a belt conveyor 44 and delivered by the latter to a roller platform 4S adjacent the molding machine 16 to be conveniently available for re-use in the latter.

In the arrangement illustrated, new sand for the molds is supplied through a oor hopper 46 outside the loop and carried along a vibrating spill conveyor 47 which passes beneath the molding machine 16, which is situated over a grid topped spill hopper 48, to the aforementioned hopper 40 which receives the used sand from the shakeout machine. The new and used sand is transported by a vertical elevator 49 to a rotating inclined screen cleaner 50 at the top of a storage bin 51. Tailings and the like pass from the lower end of the screen cleaner to a tailings chute 52 which extends downwardly and outwardly over the mold conveyor 10 to a tailings box 53, while the clean sand of course passes through the wall of the screen to the bin 51. The sand is withdrawn from the bottom of this bin, through a batch hopper 54, to a conventional muller 55 which is also supplied with the binder employed by means not shown, and the mold or prepared sand is delivered to a horizontal belt 56 which discharges the same into the lower end of a second vertical elevator 57. This last elevator `delivers the sand to a prepared sand bin 58 positioned over the molding machine 16 and having a bottom batch hopper 59 for supply of the sand to the latter.

It will accordingly be seen that mold cooling in this system takes place from the end 21 of the pouring zone, or wherever within the indicated pouring zone the particular mold was poured, back through the set-out area and the pouring zone to the shakeout, whereas in a conventional conveyor system, cooling takes place only between the pouring zone and the shakeout. With the two mold lines described, which may incidentally be reversed in the sense that the pouring could be done on the inner line and the other stations corerspondingly changed, a given foundry operation can be accomplished with a conveyor only half as long as one of conventional design. For example, in a comparative mathematical analysis in which:

E=the length between the portion of the loop between the shakeout and the start of the pouring zone;

P=the length of that portion of the loop within the pouring zone;

Dc=the pouring length of that portion of the loop from the end of the pouring zone to the shakeout in a conventional loop;

Dn=the length of the portion of the loop from the end of the pouring zone to the shakeout in a loop in accordance with the present disclosure;

Lc=the total length of the conventional loop;

Ln=the total length of the new loop;

S=the speed of the conveyor; and

T=the cooling time required on the loop,

with E, l?, S and T being the same in both loops for proper comparison, then in the conventional loop:

LFE-tintoc Expressed another way, one mold conveyor of deiinite length in accordance with the invention can therefore serve the purpose of an ordinary mold conveyor twice as long.

The other advantages of the invention discussed at the outset above are thus manifest in the illustrative embodiment described in detail.

Insofar as I am aware, the concept of shifting between plural lines of molds on the same conveyor, and there may be more than the illustrated two lines if desired, with appropriate 'positioning of the work stations with respect to such lines is entirely new in the art, although it may be old simply to carry plural molds on the same conveyor car, without operative distinction in the handling of the same. The transverse shifting which I have disclosed can obviously be Aaccomplished by a wide variety of mechanical devices other than the fluid cylinder specifically described.

Other rnodes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. The method of mold handling which comprises forming at least two lines of molds that extend in laterally spaced relation about a major portion of a closed loop, advancing said lines of molds about the loop, setting out new molds in one such line, pouring molten metal in the molds disposed in such one line, shifting the poured molds from such one line to another line in which the poured molds continue to move about the loop at least through the place of setting out new molds and substantially through the zone of pouring for such new molds in the one line, the poured molds thereby being cooled, and thereafter removing the poured and cooled molds from the loop for subsequent handling.

2. The method set forth in cla-im 1 in which said one line is the outer mold line of the loop and the molds are shifted inwardly to and subsequently removed from an inner mold line.

3. The method set forth in claim l in which new molds are formed within the loop and the poured molds removed from such other line are transferred to a shakeout station likewise within the loop, the mold flasks being delivered from the shakeout station to the place of forming the new molds.

4. The method set forth in claim l in which Weights are placed on the newly set-out molds in said one line,

closed loop mold conveyor, the steps of forming a first` line of molds on such conveyor at a mold set-out station, pouring molten metal in such molds as they advance on the conveyor in said first line through a pouring zone, transversely shifting each poured mold in the first line on the conveyor before the same returns to the set-out station to a laterally displaced position, with the poured molds thus shifted forming a second line on the conveyor, the molds in such second line being advanced through the set-out station and a substantial distance therebeyond together with newly set-out molds in the first line, and thereafter removing the poured molds from the second mold line on the conveyor.

6. In the operation of a foundry system including a closed loop mold conveyor, the steps of forming a rst line of molds on such conveyor at a mold set-out station, pouring molten metal in such molds as they advance on the conveyor in said iirst line through a pouring zone, shifting each poured mold inwardly on the conveyor as the same approaches the set-out station to a laterally dis# placed position, with the thus shifted molds forming a second inner line on the conveyor, and removing the poured molds from the second inner line at a region considerably beyond the set-out station, whereby each mold placed on the conveyor travels more than completely once around the loop and thus a substantial distance beyond the point at which it receives the molten metal for cooling of the same prior to removal from the conveyor.

7. The method set forth in claim 6 in which weights are placed on the newly set-out molds in the first line, with such weights being transferred laterally from poured molds in the second line to adjacent new molds in the rst line.

S. A mold conveying system comprising driven conveyor means for conveying at least two laterally adjacent lines of molds about a closed loop, means for delivering new molds to a set-out station at which they are placed on the conveyor means substantially uniformly in a rst longitudinal portion of the same, means in advance of such set-out station, in the direction of the conveyor travel, for shifting each mold which has moved about the loop from the set-out station to such advance point laterally on the conveyor means to another longitudinal portion of the same, so that the molds thus returned to the area of the set-out station can continue therethrough without interfering with new molds placed on the conveyor means at said station, and means for removing the thus shifted molds from the conveyor means at a region in advance of the location of said means for shifting the molds.

9. A mold conveying system comprising driven conveyor means for conveying at least tWo laterally adjacent lines of molds about a closed loop, means for delivering new molds to a set-out station at which they are placed on the conveyor means substantially uniformly in a first longitudinal portion of the same, reciprocable mold shif ing means alongside the conveyor means at a region relatively closely in advance of such set-out station, said shifting 'means being operative to extend transversely over Y the conveyor means to engage molds thereon and shift the same from such first to another longitudinal portion of the same, whereby such shifted molds can continue `on the conveyor means with further molds placed thereon at the set-out station, and means for removing the thus shifted molds from the conveyor means at a region in advance of the location of said means for shifting the molds.

l0. A mold conveying system comprising driven conveyor means for conveying at least two laterally adjacent lines of molds about a closed loop, means for delivering new molds to a set-out station at which they are placed spaanse on the conveyor means substantially uniformly in a first longitudinal portion of the same, reciprocahle mold shifting means alongside the conveyor at a region relatively closely in advance of such set-out station, said shifting means being operative to extend transversely over the conveyor means to engage molds thereon and shift the same from such rst to another longitudinal portion of the same, stop means generally opposite said mold shifting means for limiting the extent to which the latter can move the molds on the conveyor means, whereby such shifted molds can continue on the conveyor means with further molds placed thereon at the set-out station, and means for removing the thus shifted molds from the conveyor means at a region in advance of the location of said means for shifting the molds.

11. A mold conveying system comprising driven conveyor means for conveying at least two laterally adjacent lines of molds about a closed loop, means for delivering new molds to a set-out station at which they are placed on the conveyor means substantially uniformly in a iirst longitudinal portion of the same, guide means extending longitudinally closely over the conveyor means at such set-out station and defining the longitudinal conveyor means portion to receive the new molds, means relatively closely in advance of such set-out station, in the direction of the conveyor meanstravel, for shifting each mold which has moved about the loop from the set-out station to such advance point laterally on the conveyor means to another longitudinal portion of the same, so that the molds thus returned to the area of the set-out Station can continue therethrough without interfering with new molds placed on the conveyor means at said station, and means for removing the thus shifted molds from the conveyor means at a region in advance of the location of said means for shifting the molds.

12. In a foundry system including a closed loop driven mold conveyor and having a pouring zone extending over a peripheral portion of the same, means for delivering new molds to a longitudinal half-section of the conveyor at a set-out station at the same peripheral side of the loop as such pouring zone but in advance of the latter, mold shifting means reciprocable over the conveyor at a region beyond the forward end of the pouring zone and operative to shift the molds laterally on the conveyor to the other longitudinal half-section of the same, said mold s," shifting means being in advance of the set-out station thus to shift the molds to clear the first mentioned conveyor section for placement of new molds on the latter at such station, and means for removing the molds from such other longitudinal half-section of the conveyor at a region in advance of said mold shifting means.

13. The combination set forth in claim 12 characterized further in that the new mold delivery means serves the outer half of the conveyor, and said mold shifting means is disposed at the outside of the conveyor to push the molds inwardly when advanced,

14. The combination set forth in claim 13 characterized further in that said means for removing the molds comprises curved guide means extending over the conveyor for intercepting and directing inwardly the molds on the inner half of the conveyor.

15. The combination set forth in claim 14 characterized further by the provision of driven take-off conveyor means arranged alongside the loop to receive the molds guided from the latter by said curved guide means.

16. The method of molding which comprises: advancing a mold from a set-out station along a path that extends in a first section thereof from said station and through a pouring area, about a loop, and back through the set-out station and pouring area in the same direction as originally but in a second section of the path which is laterally displaced with respect to the first section of the same, the second section of the path thereby being overlapped with the first in spaced relation; pouring metal in the mold while in the first section of the path extending through the pouring area, with the poured mold thus being advanced along the loop and the overlapping second section of the path for extension of its travel and therefore increase in the time for cooling of the poured mold; and subsequently removing the poured and cooled mold for further handling.

References Cited in the file of this patent UNlTED STATES PATENTS 453,056 Welsh May 26, 1891 972,108 Herbert Oct. 4, 1910 1,123,914 Munford Jan. 5, 1915 2,068,835 Wurster lan. 26, 1937 2,229,492 Christensen et al Jan. 21, 1941

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