US1781143A - Method of making castings - Google Patents

Description

Nov. 11, 1930. J. H. WILLIAMS METHOD OF' MAKING CASTINGS 3 Sheets-Sheet 1 Filed March '7, 1927 WMM? 8 v via 5 .4 10J M 0 Z l 0 Nm Mw w 07oN na 0 7 5 l 3 Sheets-Sheet 2;

J. H. WILLIAMS METHOD OF MAKING CASTINGS Filed March 7, 1927 m wn/ (l1 Nov. 11, 1930.

Nov. 11, 1930. J. H. WILLIAMS METHOD oF MAKING CASTINGS Filed March 7, 1927 3 Sheets-Sheet 5 4free/yew satema ai. i930 JAMES H. WILLIAMS, OF DETROIT, IMICIEIIGAN', 'ASSIGNOB TO'DETBOIT AND SECURITY TRUST COMPANY, F DETROIT, MICHIGAN, A' CORPORATION OF MICHIGAN METHOD OF MAKING CASTINGS 'Ihe invention relates to the production of castings having either tubular or reentrant cross sections so that the casting when formed in the mold either wholly or partially embraces a part of the mold structure. Notable examples of such castings are internal gears and also laps of a certain type which resemble internal gears in form and which are adapted for use in the truing of external gears by the method devised by A. W. Copland and M. I. Mathewson and set forth in their U. S. Letters Patent No. 1,683,867. Such internal gears and laps are, of course, instances of castings of tubular cross section.

One of the principal objects of the invention is the provision of' an improved method by the use of which castingsof the character referred to can be produced with a high degree of accuracy.

Another object of the invention is the provision of an improved method by the use of which accurately formed castings of the char-v l'-acter last referred to can be produced with the metal of their inner surfaces highly chilled and having the fine-grain structure -characteristic of such chilled metal.

A further object of 'the invention, ancillary to those above noted, is the provision of an improved method for removing solid metal cores or mold sections from tubular or reentrant` section castings of the character referred-to.

The improved method consists essentially in pouring the casting in contact with anaccurately formed and smoothly finished metal core or other mold section having a form oomplimentary to that of the embracing surfaces of the casting to be produced; separating the casting and the core or mold section referred to from the remainder of the mold; subjecting the joint between the casting and core or mold section to liquid pressure until the liquid enters between and lubricates the abutting surfaces of the casting and core or other mold section; and then forcing the core or other mold section out of the embracing Walls of the casting. l

` As above stated, laps of the character referred to constitute a notable example of castings to which the invention is applicable, such laps being in the general nature of axially elongated internal gears, and for purposes of explanation and illustration the method and preferred apparatus for carryin it out will beidescribed in detail as applic to laps of thls character, reference being had to the accompanying drawings showing the preferred ap aratus.

n the drawings: Fig. l is a vertical section through the upper part of the apparatus for removlng the core from the casting. v

Fig. 2 is a vertical section on the line 2-2, Fig. 1.

Fig. 3 is an enlarged vertical section through a four-Way valve forming part of the apparatus.

Fig. 4 is a side elevation on a smaller scale of the entire apparatus.

Fig. 5 is a plan view of the apparatus shown in Fig. 4.

Fig. 6 is an enlarged vertical section of the lap casting and the core as they come from the mold.

Fig. 7 is a plan view of the parts illustrated in Fig.'6.

Figs. 8 and 9 show the core and lap, respectively, after they have been separated.

Fig. 10 isa vertical section on a reduced cale of the entire mold used in casting the aps.

Reference will first be made to Fi 10 which shows the main parts of a 'mol designed for the casting of the laps. The lap is to be formed with internal teeth complementar-y to those of the spur gears to be lapped thereby and consequently the metal core of the mold must be formed with external teeth similar to those of such gears. In Fig. 10 the `reference character 1 indicates the base portion of a mold which is formed of dry sand. Resting thereon in a central position is a spindle gate core 2 also of dry sand with sixteen spindles 3 formed thereon and vequally spaced around the core 2. In this core 2 at the base of the spindles 3 is an annular space 4, which serves to transfer molten metal from the feeder passage 5 and pouring gates 6 to the spindles 3 from there into the casting cavity 22 of the mold. A

- tion 7 and a lowersection 8, both formed of l ing out core 19', core12 and chills 10 and 18,

dry sand. The lower. bod'yportion -8 has a recess 15 in to which the core 2 is fitted. The spindle core 2 has a recess 9 in its upper face in which is inserted an iron chill 10.

j Complementary to core`2 and resting in a recess 11 in the upper body portion 7 of the mold is another dry sand core' 12, which has formed therein four openings '14 equally spaced around the core 12. In the up er and lower sides of the body portions 7 and 8 respectively, are recesses 16 which allow communlcation between the spindles 3 and the' cavity of the mold, and also between said cavity and the riser openings 14. The' core 12 has a recess 17 for the reception of a second iron chill 18.

In the center of the mold and resting on lower chill '10'is a steel core 19.` Extending through this core 19, and also lower core 2 chills 10 and 18, and u per core 12 is a central 4bore which is adapte to receive the central rod 20. Restin 'on the top of the core` 12 and rod 20 is a weig t 21. Surrounding the mold is a flask 22". A space 22b is provided between the walls of the mold and flask for the reception of green sand.

The mold is aembled and operated as follows: The base slab 1 is placed on a bottom of greensand, which is leveled oil' for the reception of the base. Core 2 is fitted into the recess 15 of lower body portion 8 andpis placed on base 1. Iron chill 10 is then placed in re cess 9. Steel core 19 is then placed in position, and upper body portion 7 is then placed on lower ody portion 8. Core 12 is then placed in recess 11 of mold section 7. If the steel core 19 does not match the mold in length, upper body portion 7 is rubbed on lower portion 8 until they do match. In practice port-ions 7 and 8 are purposely made longer than is required so as -to insure a proper'fit. The mold is then taken apart and the feeder assages 5 are cut. The mold is then reassem led leavand pouring gates 6 are then pasted thereon so that they will register with the feeder passages. The entire mold is then covered with paper. The flask 22 is placed around the `mold` and space 22 is packed with green sand until it is level with the top of the mold. The steel core 19 is then referably coated, while at a temperature of a out 100 F., with asolution of bone black in water. The chill 10, the steel core 19, chill v 18, core 12, rod 20 and weight 21 are all placed in position. Molten metal is then poured into gates 6 until it appears in risers 14. lThe castingis allowed to cool until it is thoroughly congealed and then the mold is broken away and the steel core 19 with the casting is removed and set upon its end to cool.

' With the above described mold and proceand dense. However, by a modified method it is possible to reduce soft iron laps or other castings. In t is latter case the chills 10 and 18 are omitted and the metal core 19 is preliminarily heated in a suitable manner to control its chilling eifectwhile, at the same time, theaJvant-a'ges of accurate form of the core are retained.

' Whether the casting produced as. above described be chilled or soft, as it cools itcontracts and more or less strongly grips the core 19 with the result that the removal of such a.

solid core from the casting without damaging the core or casting has heretofore been a practically insurmountable obstacle. But by my improved method and apparatus I am enabled to accomplish such removal.

The means for separating the lap from the' steel core 19 is shown in Figs. 1 to 9, inclusive.

The steel core 19 with a cast iron lap 23, as it comes from the mold, is shown in Figs. 6 and 7. The registering teeth of. the core and lap are indicated at 24 and 25, respectively.

Figs. 8 and 9 show the core and 1a after they have been separated by the metho and apparatus hereinafter described.

' Referring to Figs. 1,2' and 4 in detail: The apparatus has an up'per ri d clampin ring 30. Clamped to tlus ring y'means o bolts 31 and nuts 32 is anadapter plate 33. Dif# ferent size adapters can be used for diierent size laps. An opening 34 is provided centrally of the adapter so that the core 19 may be ejected from the la 23. .A boss 35 projects upwardly from t e adapter' plate and is arranged around the peri hery of the opening 34. This boss is provi ed with screw threads for the reception of a casing 36. A cover 37 is attached to the casing by means of screw threads or the like. Two openings 38 are provided in the' ring 30 for the reception of tie rods 82 for a purpose to be hereinafter described.

Arranged below and spaced from the clamping ring 30 and adapter 33, is a movable clamping plate 40. In the operation of the device the lap 23 is rigidly held between these clamping elements 33 and 40. Packing rings 41 and 42 are provided at the upper and lower ends of the lap 23'so as to prevent oil from escaping. A central bore 43 is provided in the plate 40 for the reception of a ram rod 44. It will benoted that on core 19 and lap 23 respectively, extensions 45 and 46 have been provided. Extension 45 extends into the 47 between the plate 40 and the core and lap,

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for a 'purpose to be hereinafter described.

The plate 40 is provided with a passageway .48 (Fig. 2) which leads to the annular space 47 for the passage of liquid under pressure.

A piston 53 is rigidly attached to this movable clamping plate by means of a split ring fitting into a groove 51 in the piston. This ringis secured to the plate 40 by means of screws 54. Thispiston is fitted into a recess 55 in the clamping plate 40.

The piston has an integral head 56 disposed in the cylinder 61. This head has an annular flange 57, to which the packing rings 58 and 59 are secured by means of bolts 60, thereby forming a liquid tight fit in the cylinder 61. n

The cylinder 61 is closed at both ends by means of plates 62 and 63 secured to the cylinder by means of tie bolts 64 and nuts 65. These bolts extend through the body of the cylinder and secure the plates to the ends thereof. .The plate-62 has an opening 66 in its center for the purpose of receiving the upper end of the piston 53. A liquid tight lit is provided between the piston 53 and plate 62 by a packing means 67 which is secured in the recess 68 of the plate by means of screws 69, acting on a clamping ring 69a.

An extension 75 is integral with the piston head 56, and reciprocates in an opening 70 in the lower cylinder plate 63, and thereby forms a guiding means for the piston. Suitable packing rings 71 are fitted in a recess 72 in the plate 63 and are held in place by meansv of a clamping plate 7 2"L and screws 73.

A bore 76 extends centrally of piston 53 and piston extension 75 for thereception of the yram rod 44. The lower end of extension 75 has a recess 77 cut therein. This recess together with packing 78 and cover 79 form a stuiiing box for the ram rod 44.

It will be noted from an examination of Fig. 1 that the cylinder 61 has two solid integral extensions80 arranged opposite each other and these extensions have openings 81 for the reception of tie rods 82, and also openings 83 for the reception of bolts 64. The remaining tie bolts 64 engage the cylinder through integral iianges 84, seen in Fig. 2. The lower end of ram rod 44 terminates in a piston 85. This piston has an integral flange 86 to which packing rings 87 are secured by means of plate 878L and screws 88. Enclosing the piston is a cylinder 89 having integral extensions 90 in which the openings 91 are provided for the reception of the tie rods 82.

The lower end of the cylinder 89 is closed by means of the plate 92 and stud bolts 93. The upper end is closed by means of a plate 94 and stud bolts 95. The plate 94 has a vcentral opening 96 for the passage of the ram rod 44. A suitable packing means 97 is provided in the opening 96 for the ram rod, so as to form a fluid tight connection.

The reference character 100 denotes a pipe line (see Fig. 2) which is connected at its lower end to a suitable oil pump or accumulator (not shown) for delivering oilv under pressure to the apparatus. Connected to the upper end of this pipe line is a flexible conduit 101, which in turnf is connected at its other end to a suitable connection 102 on the movable plate 40. This connection 102 is threaded into the outer end of passage 48 in the clamping plate. This conduit 101 is made exible so that.. the plate 40 will be free to move. A valve 103 of ordinary construction controls the How of oil to the movable clamping plate.

- The clampmg cylinder 61 has oil ports 104 i and 105 arranged at its upper and lower ends respectively, so as to allow oil under pressure to enter the said cylinder on either side of piston head 56 to control the movement of the same. Oil also exhausts through these which is shown in detail in Fig. 3. The valve casing 107 of this valve 106 has four openingsequally spaced around the same. The openings 108 is connected to the pressure line 1'00, and opening 109 is connected'to the exhaust line 110 which leads to a suitable oiLsupply reservoir (not shown). Openings 111 and 112 have connections which lead to the oil ports 104 and 105, respectively, of

ports 114, the other end of the cylinder will be in communication with the exhaust line 110, through the other valve port 114.

Cylinder 89 has ports 115 and 116 at opposite ends thereof. These ports are connected to supply line 100 and exhaust 110 by means of a second fourway valve 117. This four-way valve 117 is identical, in construction and operation, with valve 106v described above. The movement of piston 85 is controlled by the operation of the valve 117 in the same manner that piston head 56 is controlled by valve 106.

The upper end of ram rod 44, see Fig. 1, has a reduced extension 120 which projects into bore 43 of clamping plate 40. In this extension 120 is a right-angle passageway 121, which acts as a means for equalizing the oil presssure in a manner to be hereinafter .base 125 which'has a flange 126 provided arounditsouter edge so as to catch any oil which may leak out of theconnections.

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I'n the movable clamping plate 40an annular trough 127 is provided to catch the oil which may escape when the la 23 and core 19 are removed. vTrough 12 is connected with a return oil pipe A128 which leads to the supply reservoir. Base 125 is connected by means of conduit- 129 to this return pipe 4128. (See Fig. 4.) This base 125 is adapted to be mounted on Isome suitable support (not shown) s uch as a floor ofthe buildlng, or the like.

As `can be seen from an examination ofl seen from anexamination of Figs. 1 and 4.

Nuts 136, 137 and 138 are attachedA to the tie rods so as to draw the several parts together` on their spacing sleeves,'thereby rigidly securing the several parts to each other. The movable clamping plate has openings y 150 through which the tie-rods 82 and spacing sleeves 132 extend. This is for the purpose. of guiding the movement of the plate 'It will be seen from an examination of Figs. 1 and 2 that the steel core 19 has a bolt 145 with a beveled head 146 secured in its cent-ral opening 147 by means of a nut 148. The bolt 145 is placed in the opening so as not to allow any oil to pass linto casing 36 during one step in my process. It will be noted that between lthe cylin 'der 61 and the ring 30 I have shown the several spacing sleeves 133, 134 and 135 of different lengths. These sleeves are adapted to be removed or added at the will of the operator so, as to adapt the machine to different length laps 23.

vIn carrying out my .improved method, the operation of the apparatus is as follows: When the cast iron lap 23 and the embraced mold section (in this case the core 19) have cooled suilici'entlyafter'having been removed from the mold, the lap is machined or otherwise prepared for use. Then the bolt 145 is secured in the aperture 147 of the steel core 19 by means of the nut 148, and the steel core with the lap thereon is placed in position with the lap 19 registering with the opening 34 in the adapter plate 33. v The packing rings `41 and 42 having been placed in position, oil under pressure is admitted through four-way valve 106 tothe port 105 of the cylinder 61 thereby moving the piston 53 upwardly. This piston 53' carries the lower clamping plate 40 with it.-Y This plate 40 engages the projection 46 on the lap 23 and thereby firmly clamps the lap between it and the adapter plate 33. The projection 45 on the core 19 extends into the bore 43 of the plate`40. (lap 37- having been removed from the casing 36,

valve 103 is opened thereby allowing oil un der pressure to enter the annular space 47 formed at'the lower end of the lap and core, through the opening 48 in the plate 40. This Oil under pressure isl forced between the abutting surfaces of lteeth '24 and 25. This latter The above described operation isl in mostcase'ssucientto extract .the core from' chilled v ironlaps. .Shouldl this operation fail to do the work,`valve 117 is turned Iin such a manneras to allow oil under'pressure to enter through port 116 .to the cylinder 89. This operation will cause the piston carrying the ram rod 44 to move upward. vThe continuation of this upward movement of the ram rod 44 causes it to strikethe head 146 of the bolt 145 arranged in the central opening in the core and thereby mechanically eject the' core from the lap.

However, should this latter operation fail,

the core and lap are then. taken from between 'I the two clamping plates, the bolt 145 is re'- moved therefrom and the core and lap, are then placed between Athe two clamping plates as before and the cap 37 is placed inr position 'on casing 36.. It will be noted that the upper end of ram rod 44 and also the projection 45 on the lower end of the steel core fit loosely in the bore 43 of the movable clamping` plate. It will also be noted that a right-angle passageway 121 is Alocated in theupper end of the ram rod 44. Pressure is again admitted through valve 103 -to .the annulus 47. Oil under pressure will then find its wa into .the upper casing 36 due to the loose fittlng of the projection 45 with the bore 43, thepassage` way 121 and the central opening 147 in the core. Itwill be seen that oil under pressure is then being forced along the gear teeth 24 and 25 from both ends and this is continued until the oil has fully penetrated between and lubricated the abutting surfaces of the lap and core, and by expanding the lap or outer part, relieved the shrinkage pressure on the core, either in part or entirely, thereby causing separation of adjoining surfaces or relief of er part is thus under' pressure valve 117 is opened lto allow oil under pressure to pass through opening 116, raise piston 85, and ram 44, and thereby forcibly ejectV core 19 into casing 36. The pressure is cut off by proper manipulation of valves 117 and. 103, the cap bearing between them. While the lapor out- 37 is removed and the core is then lifted out of the casing.

When the abutting surfaces of the lap and core are lubricated in the manner described, the core can be forced from the lap without undue pressure and consequently without injury to the said surfaces. The result is that by my improved method of casting it is possible to produce a casting of annular or tubular cross section having its inner surfaces formed With a relatively high degree of accuracy. Also as pointed out, the casting can be made either chilled or soft.

I have referred to the casting 23 as a cast iron lap and to the part 19 as a steel core, but it will be understood that this is for illustrative purposes only and that the casting may be either in the form of a lap, an internal gear or any other casting of tubular or annular shape or having reentrant walls, which it is desired to form with Vaccurate surfaces or which it is desired tof'orm of chilled metal. Furthermore, it is obvious that the casting may be made of metals other than iron.

lVhile I have described the preferred procedure for the carrying out of my invention it will be understood that there can be wide variation therefrom without departing from the invention as defined in the appended claims.

VWhat I claim is 1. The method of forming annular or reentrant section castings which comprises pouring molten metal around a metal mold section; removing the casting and mold section from the remainder of the mold; subjecting the joint between the casting and mold section to the pressure of liquid outside the joint until the liquid enters between and lubricates the abutting surfaces of the casting and mold section; and forcing the mold section out of the embracing walls of the casting.

2. In the method of forming annular or reentrant section castings, the steps which comprise: pouring molten metal around a metal mold section; removing the casting and mold section from the remainder of the mold; subjecting the joint between the casting and mold section to the pressure of liquid outside the joint until the liquid enters between and lubricates the abuttingsurfaces of the casting and mold section and separates them.

3. In a method of forming annular or reentrant section castings, the steps which comprise: pouring molten metal around a metal mold section; removing the casting and mold section from the remainder of the mold; subj ecting the joint between the casting and entrant section castings, the steps which comprise pouring molten metal around a metal mold section; removing the casting and mold section from the remainder of the mold; subjecting the joint between the casting and mold section to liquid under pressure outside the joint at each end thereof until the liquid enters between and lubricates the abutting surfaces of the casting and mold section and separates them.

5. In a method of forming annular or reentrant section castings the steps which comprise pouring molten metal around a metal mold section; removing the casting and mold section from the remainder of the mold; subjecting the joint between the casting and mold section to liquid under pressure outside the joint at each end thereof until the liquid enters between and lubricates the abutting surfaces of the casting and mold section and separates them; 'and then forcing the mold section from the embracing walls of -the casting.

In testimony whereof I afiix my signature.

JAMES H. WILLIAMS.

mold section to the pressure of liquid outside the joint until the liquid enters between and lubricates the. abutting surfaces of the casting and mold section, thereby separating them; and then forcing the mold section out of the embracing Walls of the casting.

4. In a method of forming annular or re-

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