US1974144A - Casting machine - Google Patents

Description

p 1934- R. o. WATKINS CASTING MACHINE Fi led June 20, 1952 5 Sheets-Sheet 1 0. Z l/ai'im fijuzlovv 7 a Sept, 18, 1934. R. o. WATKINS CASTING MACHINE Filed June 20, 1932 5 Sheets-Sheet 2 Sept; 18, 1934. R. o. WATKINS CASTING MACHINE Filed June 20, 1932 5 Sheets-Sheet 5 5 7% xw mp fwenir 0. ZUCZZ U25 R. o. WATKINS CASTING MACHINE Sept; 18, 1934.

Filed June 20, 1932 5 Sheets-Sheet 4 flay 0. 206141-71: yfiyww m xw Sept- R. o. WATKINS CASTING MACHINE Filed June 20, 1952 5 Sheets-Sheet 5 Patented Sept. 18,1934

PTENT OFFICE (CASTING MACNE Ray 0. Watkins, Chicago, 111., assignor to Universal Battery Company, Chicago, 111., a corporation of llllinois My invention relates in general to casting machines and more in particular to a casting machine for producing storage battery grids.

The principal object of the invention is the provision of an improved casting mechanism.

Another object is the provision of an improved mechanism for casting grids in which the lead alloy is pumped from a lead kettle into molds in synchronism with the driving means for the mold.

Another object is the provision of improved pouring mechanism adapted to operate in combination with a mold carrying frame.

Another object is the provision of an improved pouring mechanism including improved means for controlling the amount of metal poured and the flow thereof.

Another object is the provision of an improved lead pump mechanism.

Other objects and features of the invention will ing detailed description taken with the accompanying drawings, wherein Fig. 1 is a plan view of the entire mechanism, the usual lead pot being partly broken away to conserve space;

' Fig. 2 is a side elevational view thereof, part of the mechanism being shown in section;

Fig. 3 is an elevational view partly in section looking at right angles to Fig. 2;

Fig. 4 is an elevational view partly in section looking at the opposite side of Fig. 2;

Fig. 5 is a plan sectional view taken along the line 5-5 of Fig. 2;

15 Fig. 6 is a sectional view taken along the line 66 of Fig. 3;

Fig. '7 is an enlarged fragmentary vertical view taken on the line '7'7 of Fig. 1:

Fig. 8 is a transverse section taken through the lead pump on the line 8-8 of Fig. '7;

Fig. 9 is a slightly irregular sectional view taken on the line 9--9 of Fig. 8.

Referring now to the drawings, the mold supporting and operating mechanism includes a main base frame 11 which carries a stationary vertical shaft 12 to which a head 13 is secured against'rotation. A mold carrying frame 14 is rotatably supported on the shaft 12 and has secured thereto a 'mold frame extension 16 which actually carries the molds. A frame 14 is shaped on its under side with a plurality of edge radial slots 01' grooves 17 into which one of three rollers 18 carriedv on a three arm spider 19 is adapted to engage and intermittently rotate the entire frame.

be apparent from a consideration of the follow- I For driving the three arm spider I provide a motor 21, the drive shaft of which has a small sprocket gear 22 which drives a sprocket chain 23, the sprocket chain in turn driving arelatively larger sprocket gear 24 carried on a shaft 26. of) This shaft has a worm 2'7 which meshes with a worm gear 28 carried on a shaft 29, which shaft 29 is suitably journaled in the main base frame. The three-arm spider 19 is keyed to an upright shaft 31 and beveled gears 32 and 33 carried reso spectfully by the shafts 31 and 29 transmit the movementof the shaft 29 to the shaft 31.

The shaft 31, therefore, rotates continuously and the three-arm spider also rotates continuously. The arms and slots 1'7 are so dimensioned that a roller 18 enters a slot just as another roller 18 leaves a slot. At this time the portion of the slot which the rollers engage is substantially tangent to the circle described by the rollers 18 so that as a result the frame 14 is held stationary for a short length of time. When the frame 14 moves, it accelerates until the parts are in the position shown in Fig. 5, at which place the frame is moving at its most rapid rate. As the three-arm spider, however, continues to move in the direction indicated by the arrow, movement of the frame 14 is gradually decelerated until just as the arm is about to move the roller out of a slot, movement of the frame 14 is entirely arrested. By designing the drive so that 35 one arm is engaging as the other arm is disengaging, I find that it is possible to obtain substantially any desirable control of the mold carrying frame. I may even cause the frame to move slightly backwardly as the roller 18 leaves the slot. Modifications of the movement obtained by the structure shown, however, will usually require that the slots 1'7 be so shaped as to be no longer truly coincident with the radius of the frame.

The molds carried by the mold carrying frame are bi-part, one. part 34; being stationary and the other 'part 36 being relatively movable. The molds, six in number, are carried radially of the frame and there being six slots 1'7 and the threearm spider 19 being proportional accordingly, each movement of the frame will be equivalent to the circumferential space between centers of the molds. In this Way, the molds seriatim will be presented to the mold pouring position A (Fig. 1) at which place the molds having previously been emptied are filled with lead alloy.

A cam 3'7 on the underside of the head 13 controls the movement of the movable mold portion. A plurality of rollers 38 confined in the l cam 37 are moved by the cam and are provided with connections, as shown, to the movable mold whereby movement of the rollers is imparted to the movable molds. As Fig. 1 shows, the molds are opened at a mold dumping or grid discharging position B.

Molten lead alloy in suitable amounts is maintained in a lead pot 39 and I employ lead pumping mechanism for Withdrawing the lead from the pot and discharging the same in the form of a sheet into the mold during the brief interval at which the mold carrying frame is stationary and the empty mold is presented to the lead pouring position.

Now, as to the details of the lead pumping mechanism, I provide a lead cylinder 41 (Fig. 7) closed at the bottom by a plate 42 and having a piston 43 reciprocable therein. This entire assembly is buried under the liquid lead so that litharge, oxides, dirt or foreign matter which may fioat on the top of the lead under no circumstances will be permitted to enter the lead pump. 1

A piston rod 440, is pivotally supported on the inside of the piston and is reciprocable in a manner to be described to operate the piston up and down whereby, by means of the valve mechanism employed, lead is withdrawn from the lead pot and fed to the mold.

The piston 43 is hollow and lead is delivered to the cylinder by passing through valve control ports 44 in the base of the piston. A valve 46 has its stem extending through the piston face and the stem has a rim 47 for holding the valve in position. When the piston is drawn up, it is ob'vious'that the lead will pass through the ports 44, forcing the valve away fromits seat. The valve, however, being made of steel, is lighter than the lead and tends to float to the top of the lead in the cylinder and close the ports. When the piston is moved downwardly, the valve already being substantially against its seat is forced still tighter against its seat and closes the ports 44. I

The lead delivered from the lead pump passes upwardly through a pipe 47a into a delivery nozzle 48. This delivery nozzle comprises a lower portion 49 and an upper portion 51 secured together by machine screws 52. The lower portion is provided with an extension 53 for securing the spout to a bracket 54, which bracket is attached to the side of the lead kettle by cap screws 56 (Fig. 1). The lower portion also has a boss 57 into which the pipe 47a is threaded, whereby lead delivered through the pipe 47a is passed to the interior of the spout.

The lead delivery spout is fan shaped, as shown in Fig. 1, and the delivery opening is substan' tially as wide as the gate of the grid mold. At the delivery end the vertical distance between the two portions of the spout is relatively small. A small but sharp projection 58 runs entirely across the delivery opening.

As the lead is delivered from the pump to the delivery opening in the spout, the entire spout and the pipe 47a are maintained filled with lead. To prevent this lead from running back and also to insure a refilling of the cylinder on the upstroke of the piston, I provide a ball check valve 59 (Fig. 9). This ball check valve is in a relatively restricted chamber, the upper portion being formed to provide a seat 61. Above the seat a radial chamber 62 is provided communicating with the interior of the cylinder below the piston. A chamber 63 communicates with the chamber housing the ball. The ball 59 is steel and being lighter than the lead, it also tends to float against the seat 61. The body of lead in the pipe 47a and above it tends to maintain this ball against the seat. The pumping or downstroke of the piston, however, will force the ball away from its seat sufiiciently to pass the lead into the chamber 63 and thence through the delivery pipe 47a.

Any suitable means for supporting the pump in the body of lead may be employed. In the present embodiment, the cylinder 41 has side projections to which rods are attached, these rods being carried in projections 65 from the bracket or frame 54. In this way the lead pump once being set is always maintained in the same position in the lead pot. This construction, moreover, supports the lead pump firmly and facilitates the operation of the piston and piston rod.

I operate the piston so that it moves downwardly and delivers a flat sheet of lead to the mold at the instant that the mold comes to a stationary position. The lead pump, therefore, is driven in synchronism with the mold moving and operating mechanism.

For operating the lead pump, I provide a cam 66 on the shaft 29. This cam engages a roller 67 carried on an arm 68, which arm 68 is keyed to a transverse shaft 69. The end of the shaft 69 projecting through the base 11 has keyed thereto an arm '71. The movement of the arm 68 by the cam 66, therefore, through the shaft 69, operates the arm 71; and the movement of the arm 71 is transmitted to the piston.

A rod 72 is pivoted to the arm 71 at 73. A bracket 74 carried by the frame has a fork shaped projection 76 through which the rod extends, and a spring '77 has one end bearing against the projection 76 and the other end bearing against a nut 78 adjustable on a threaded sleeve 79 pinned to the rod. At the upper part of the rod, a sleeve 81, loose on the rod, has one side bearing against a collar 82 pinned to the rod and the other side against a spring 83, the opposite end of the spring being retained by a nut 84.

The sleeve 81 carries a pin 86 which extends through a boss 87 on an arm 88 pinned on a rocker shaft 89. This rocker shaft carries a second arm 91 provided with a boss through which a pin 92 projects, this pin being a projection from a sleeve 93 adjustable on the piston rod 44a.

With the construction described, the piston is raised when the arm 68 is depressed by the cam 66 and at the same time the spring '77 is compressed. When the cam rotates until a lower portion is adjacent the roller 6'7, the spring 77 is allowed to expand, thus forcing the piston down on a pumping stroke and causing the roller to follow the cam. The spring 83assists in smoothing out the action and is also of value should the lead become cold and freeze in the pump. In this case, the rod 72 would continue to move up and down, but the only action would be to alternately compress and expand the springs '77 and 83. It should be remembered that the spring '77 is considerably stronger than the spring 83.

As shown, particularly in Fig. 2, the cam 66 is a three part cam,one rotation of the cam causing the pump operating rod to move through three cycles of operation. Since the cam is operated at the same speed as the shaft 31. carrying the three-arm driving spider, the movement of the pump and the movement of the molds is always in synchronism. Moreover, the cam is forcing the arm 68 downwardly at the same time that the molds are being rotated; and at the stationary position of the molds, the spring 7'7 is moving the rod to cause the lead to be pumped. The speed at which the rod '72 is returned is determined by the tension of the spring 77 and accordingly this spring can be adjusted to regulate the speed of the pumping action.

I may also' regulate the length of stroke by controlling the rocking movement of the shaft 69. This may, of course, be accomplished by substituting the cam 66-for a cam of different contour. I control the movement of the shaft, however, so that the same efiect is obtained as if the cam were changed.

The shaft 69 has a control arm 96 keyed to it and this control arm projects underneath a vertically movable threaded rod 97 (carried by the base 11). By rotating this arm, its bottom end which is engaged by the arm is adjusted. If this rod is rotated until it moves at an extreme upper portion, the roller 6'7 will be permitted to follow the cam all the way in to the lowest portion thereof as the cam rotates. By lowering the rod 97, however, the arm 96 which moves upwardly with the arm 68 will have its upward movement arrested by engaging the rod 97. This will prevent the roller 6'7 from following the cam which will have substantially the same effect as if the shape of the cam were changed. Since the movement of the piston rod 4.4 is directly proportional to the movement of the operating rod 72, and the operating rod '72 in turn depends upon the rocking movement of the shaft 69, it follows that limiting the movement of the arm 68 keyed to the shaft 69 will limit the stroke of the pump piston.

I also provide this arm 96 for preventing the movement of the lead pump entirely if necessary; A shut off arm 98 is pivoted to the frame at 99 and has its lower end rounded and adapted to engage a roller 101 on the arm 96 cam fashion. so that movement of the arm in a counter-clockwise direction (Fig. 4) will move the arm 96 downwardly and take the roller 6'7 entirely out of contact With the cam 66.

A shut-off arm 102 for the entire mechanism is provided at a place convenient to the operator. This arm rotates a shut-off rod 103 which through suitable mechanism disengages a main clutch 104. This clutch is on the shaft 26, which is driven directly from the sprocket chain 23. Since the movement of all of the parts is from the shaft 26, disengaging the clutch 104 will shut off the entire mechanism. This is a temporary shut off, however, as when the mechanism is entirely shut down, current to the motor is shut off by means of a suitable electric switch.

The mechanism operates substantially automatically, a single workman being sufiicient to care for the grids as they are discharged from the molds, to replenish the lead kettle periodically and to generally supervise the entire operation. At each time that the mold carrying frame stops, a mold is presented to the pouring position and the pump is operated. The shape of the spout is of importance in connection with the pouring. A wide fiat sheet is delivered to the mold each time the piston moves downwardly. The sharp projection 58 at the mouth of the spout serves a useful purpose. The

' surface characteristics of the lead .are such that when the movement of lead through the spout is ceased, the lead will bead up along the sharp projection and be held there by its own surface tension characteristics and its own weight, so as to seal the opening and prevent the entrance of air which would cause an oxidation of the lead. The only portion. of the lead, therefore, which is exposed to the air is a very small portion immediately at the mouth of the spout.

Lead kettles vary in shape and since it sometimes becomes necessary to employ my mechanism with different types of lead kettles, there are times when the pump has to be set at an extreme angle. It is, of course, understood that I contemplate the slight changes necessary in the check valve so that the ball 59 will seat properly with the pump at any angle.

What I claim as new and desire to protect by' Letters Patent of the United States is:

1. In a casting mechanism of the character described, a lead pump adapted for mounting in a lead pot including a stationary cylinder and a piston movable therein, a source of fiuid lead in said pot, a rotatable cam having a cam periphery with high and low points thereon, an arm engaging the periphery of the cam, a rocking shaft for carrying said arm, connections between said arm and the piston of the lead pump for reciprocating the piston, and stop means operating on said rocking shaft for preventing the arm from following the periphery of the cam into the lowermost points thereof whereby the stroke of the piston may be controlled.

2. In a battery grid casting apparatus, a lead pump adapted for mounting in a lead pot, said pump including a cylinder removably supported in said pot and a reciprocable piston, a piston rod, a bell crank lever mechanism, one arm of the bell crank lever mechanism connected to said piston rod, a cam having a peripheral cam surface with high and low points thereon, a bell crank mechanismxadjacent thecam and having one arm engaging the surface of the cam, an actuating rod connected to one arm of the bell crank mechanism associated with the piston and to one arm of the bell crank mechanism associated with the cam whereby to reciprocate the piston in accordance with the peripheral shape of the cam.

3. A casting mechanism as defined in claim 2, including a spring, a bracket engaging one end .of the spring and adjustable means carried on the actuating rod engaging the opposite end of the spring, whereby said rod is moved in one direction by the spring and in the opposite direction by the cam, and whereby the compression in said spring may be controlled by said adjustable means to determine the rate of return movement.

4. A casting mechanism as defined in claim 2, including a rocking shaft for the bell crank mechanism adjacent the cam, a second arm secured to said rocking shaft, and a stop acting on said second arm to limit the movement of the actuating rod.

5. A casting mechanism as defined in claim 2 wherein the engagement between the rod and first mentioned bell crank mechanism includes 'a sleeve carried by an arm of said bell crank mechanism, the rod projecting through the sleeve, a collar on the rod engaging the sleeve at one end ill thereof, a spring engaging the opposite end of direction when spring is released, the first mentioned spring co-operating with the second mentioned spring to permit movement of the actuating rod upon the freezing of the piston in the cylinder:

-6. Ina battery grid casting mechanism, a lead pump including a cylinder adapted to be supported in a lead pot, a piston recipro'cable in said cylinder, an intake valve mechanism in the base of the piston to supply the cylinder withleaol upon movement of the piston, a discharge port in said cylinder having a check valve therein, and a spout having connecting means extending from said discharge port, with said spout being relatively fan shaped with a restricted opening at the delivery end thereof, and means in said spout co-operating with the check valve and intake valve to maintain said spout filled with lead to the opening in the delivery end thereof.

7. The combination defined in claim 6, wherein said spout comprises a lower and an upper portion, and a relatively sharp upwardly extending projection from the lower portion adjacent the outer extremity thereof running the full width of the mouth of the spout to facilitate control of the lead at said spout.

8. In a casting mechanism of the character described, a lead pump consisting of a stationary cylinder and a piston movable therein, the pump being disposed in a body of molten lead, a rotary cam, a rod, means for moving said piston in response to end movement of said rod, a spring surrounding said rod, a stationary stop engaging one end of the spring, a. stop adjustably carried by the rod engaging the opposite end of the spring, and connections between the cam and rod to move the rod against the tension of the spring, said piston moving means operating to withdraw the piston when the rod is moved loy the cam, whereby said rod is returned by the spring on the working stroke of the piston, the speed of return being regulated by the adjustable stop on said rod.

9. In a casting mechanism of the character described, a cylinder adapted to be inserted in a lead pot containing a supply of molten lead, means for holding said cylinder at an angle in said lead pot, a cylinder head closing the lower end of the cylinder, a cup-shaped piston reciprocable in the cylinder, 9. piston rod pivotally secured to the piston intermediate the ends thereof, a valve port in the base of the piston, a valve slidable in the base of the piston adapted to cover said port on the pressure stroke of the piston but to allow lead to flow through the port into the cylinder on the suction stroke of the piston, a discharge nozzle, 2. connection to the discharge nozzle at the lowermost edge of the cylinder, and a check valvein said cylinder discharge connection.

10. In a casting mechanism of the character described, a cylinder adapted to be inserted in a lead pot containing a supply of molten lead, means for holding said cylinder at an angle in said lead pot, a cylinder head closing the lower end of the cylinder, a cup-shaped piston reciprocable in the cylinder, a piston rod pivotally secured to the piston intermediate the ends thereof, a valve port in the base of the piston, a valve slidable in the base of the piston adapted to cover said port on the pressure stroke of the piston but to allow lead to flow through the port into the cylinder on the suction stroke of the piston, a discharge nozzle. a connection to the discharge nozzle at the lowermost edge of the cylinder, and a check valve in said cylinder-discharge connection, said nozzle being fan shaped and having a width substantially equal to a mold into which it is adapted to discharge, but restricted vertically, with a continuous sharp projection at its lower edge.

11. In a casting mechanism of the character described, a source of molten lead, a discharge nozzle, pump means for withdrawing lead from said source and delivering the same to the nozzle, said nozzle being fan shaped and inclined to the horizontal, the delivery mouth relatively wide but narrowed vertically, and having a continuous sharp upward projection at its lower edge, whereby lead is discharged in a fiat sheet, and after discharge a lead seal is formed at said delivery mouth and only a small area of lead is in contact with air.

RAY O. WATKINS.

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