US1193322A

US1193322A - Fluid-metal-injecting mechanism for type-casting machines

Info

Publication number: US1193322A
Authority: US
Publication date: 1916-08-01
Anticipated expiration: 1933-08-01

Description

APPLICATION FILED IAN. I6, IBIS.

Patented Aug. 1, 1916.

4 SHEETSSHEET I.

W. L WALTZ. FLUHJ METAL INJECTING MECHANISM FOR TYPE CASTING MACHlNkS.

Patented Aug. 1, 1916.

4 SHEETS'SHEET 2.

MHZ/2.1.11.1

W. L. WALTZ.

FLUID METAL INJECTING MECHANISM FOR TYPE CASTING MACHINES.

APPLICATION FILED JAN. 16, 1915.

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W. L. WALTZ. FLUID METAL lNlECTlNG MECHANISM FOR TYPE CASTING MACHINES.

APPLICATION FILED IAN. I6 1915- 1,193,322. Patented Aug. 1,1916.

4 SHEET$-$HEET 4.

fluwwto p wi tmewao UNITED STATES PATENT OFFICE.

WILLIAM L. WALTZ, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO LANSTON MONO- TYPE MACHINE COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF VIRGINIA.

Specification of Letters Patent.

Patented Aug. 1, 1916.

Application filed January 16, 1 915. Serial No. 2,788.

T 0 all whom it may concern:

Be it known that I, \VILLIAM L. \Vanrz, a. citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Fluid- Metal-Injecting Mechanism for Type-Casting Machines; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this s ecification, and to the figures and letters 0 reference marked thereon.

This inventionjrelates to a new and improved fluid meta-l; injecting mechanism of that type commonly employed in type cast ing machines for supplying metal to the" mold, in which the type 15 given its form.

Machines of the character mentioned are now well understood and in extensive use and the present inventionfor the purposes of this application is illustrated in connection with the fluid metal injecting mechanism described in the patents to J. S. Bancroft, No. 625,998, May 30, 1899, and 674,374, May 21, 1901, to which patents reference may be had for a more complete understand ing of the known parts of the apparatus illustrated herein, and some only of which will be hereinafter referred to in connection with the description of the invention.

The objects of the invention are to provide an exceedingly simple arrangement of the pump mechanism and parts associated therewith for controlling the movements of the molten metal whereby the type cast in the mold will be substantially free from internal cavities of a )preciable size and will not only have a etter appearance but will be of correspondingly greater strength and durability as well as more uniform in character than are the type produced by the standard commercial machines.

In accomplishing the results aimed at, provision is made whereby the movements of the molten metal in the pump cylinder and passages associated therewith will be more definitely and accurately controlled so as to reduce the draw-back of the metal from the nozzle and insure a complete filling of the pump cylinder and passages with molten metal free from air, which metal will be advanced by the pump piston to completely fill the mold in making the cast,

Referring to the accompanying drawm-gs,-Figure 1 is a top plan view of a type casting machine embodying the present invention but with man of the well known parts omitted. Fig. 2 is an elevation partly in section of the pump mechanism, the point of view being at the right hand of the machine shown in Fig. 1. Fig. 3 is a sectional elevation through the pump and melting pot, with certain parts of the casting machine and mold. Fig. 4 is a detail section on an enlarged scale of the pump cylinder, nozzle, and passages for the admission and discharge of the molten metal. Fig. 5 is a perspective view showing the arrangement of the valve operating mechanism shown in plan in Fig. 1 and in elevation in Fig. 2.

Like letters of reference in the several fig ures indicate the same parts.

As hereinbefore stated, the present invention is illustrated in connection with a castmg machine, such as that set forth in Patent 625,998, and in order that the parts of the machine illustrated in the accompanying drawings may be recognized in connection w th the corresponding partsiIIuStrated in said patent "they are identified by corresponding reference numbers; thus, the reference number 370 indicates the main shaft, which is one'of the cam shaftsof the machine, and carries at one end the fast and loose pulleys 373. One of the pairs of cams rotated by the shaft. 370 is indicated at 377 being designed to operate the type ejector or pusher 259, through the intermediate bell crank lever 331, connecting rod 332 and operating lever 333. So far as the other portions of the machines are concerned, they are or may be in all respects similar to that illustrated in the said patent and need not be hereinafter referred to, inasmuch as they have no direct operative connection with the metal injecting mechanism of the present invention.

Specifically, and excluding the mechanism of the present invention, the fluid metal injecting mechanism illustrated, corresponds to that illustrated in the other of the two above mentioned patents, to-wit: 674.374 and reference numbers have been applied thereto corresponding to the reference numbers in said patent; thus, the pump plunger or piston is indicated at 15 and the body of the pump at 16.

17 indicates the arm through which the discharge or eduction passage is formed and 18 the nozzle for cooperation with the nozzle plate or base of the mold. The body of the pump is given a movement toward and from the mold by mechanism including the levers 23 and 24, and the pump piston or plunger is moved or reciprocated through the medium of

levers

35 and 36 connected together by an intermediate link 37, the outer ends of said levers being in pivotal engagement with the pump body and plunger respectively. The inner end of lever 36 pivotally engages a swivel 48 on the cross head 57, and the inner end of lever 35 engages the lower end of the upwardly extending rod 41 working in a head or arm 40 connected with a vertically movable operating head 39. Above the arm 40 and surrounding the rod 41 is a spring 43, through which the power for advancing the plunger is transmited, whereby the plunger may be arrested in its movement, while the operating head continues to make its full stroke. The melting pot 12 is supported upon a vertically movable and swinging frame 2, carried by a fixed part of the main frame 1 and adapted to be elevated or lowered by a screw 3, all corresponding to the commercial machine and as set forth in said last above aentioned patent.

In the operation of the metal injecting mechanism or pump it will be understood that the nozzle is seated in contact with the nozzle plate or base of the mold 100, after which the pump plunger 15 is caused to descend so as to force the molten metal through the discharge passage into the mold, and as soon as the metal in the mold has sufliciently hardened to prevent the same from running out, the plunger is retracted or elevated and the nozzle lowered so as to permit of the removal of the type from the mold and the preparation of the parts for the casting of the next type. To prevent clogging of the nozzle or the freezing of the metal therein, as well as to prevent the untimely discharge of metal from the nozzle, it has been customary to draw or permit the metal in the nozzle to flow back for a certain distance in the discharge passage, provision being made, however, to permit the pump to receive an additional increment of molten metal through an induction passage, which in some instances extends partly through the wall of the pump body and partly through the plunger and piston itself.

In the present invention provision is made whereby the supply of metal to the pump cylinder may be accurately controlled regardless of the variation of pressure within and without the pump cylinder, due to the piston movement, by providing a valve in the intake passage, which valve is operated independentlv of the operation of the pump piston, whereby the movements of the two may be made non-synchronous, thus providing for a close and accurate control of the suction exerted by the piston on the metal in the discharge passage. The withdrawal of said metal from the end of the nozzle may thus be made suflicient to insure proper clearance, but insuflicient to permit of the entry of air in quantity which would be diflicult to get rid of and which would, therefore, tend to become incorporated in the body of the casting. In connection with the mechanically operated valve for controlling the admission of fresh molten metal to the pump cylinder, a non-return valve is preferably employed near the discharge end of the eduction passage, such valve being usually located at the base of the nozzle. This valve is of a type, which while it will permit of the free flow of the metal toward the discharge, will check the return of such metal after a limited quantity has passed the valve. The desired result can best be obtained by providing a valve which will float in the molten metal, such for example, as a ball valve, and permitting it to have a movement sufiicient to insure the return of a portion of the metal from the nozzle before the valve is carried down to its seat either by the rush of metal from the nozzle passage or by the lowering of the level of the metal around the valve.

By reference to Figs. 3 and 4 it will be seen that the pump cylinder 101 is provided with an eduction or discharge duct 10-2 extending through the arm 17 and through the nozzle 18, and it is also provided with an induction or inlet passage 103 which communicates with a valve chamber 104 having an inlet port or passage 105 usually arranged around the valve stem 106. The valve stem carries a valve 107, preferably a conical valve, adapted to seat upwardly for closing the port or passage 105 and to open downwardly or in the direction in which the metal flows into the valve chamber and induction passages. Conveniently, the valve chamber is formed in an offset 108 of the pump body closed at the lower side, and a guide formed for the lower end of the valve stem by a thimble or plug 109 which is forced into place with a tight fit and prevented from escaping by a retaining arm 110 clamped to the pump body by a closure 111 customarily employed at the lower end of said body. Vith this construction the commercial form of pump body now in use may be employed, the arrangement being such that all metal admitted to the pump cylinder enters through the valve controlled induction passage 103 105.

The upper end of the valve stem 100 (see Figs. 2 and 5) is pivotally connected to a lever 112 fulcrumed on a standard 113 carried by the frame forming a part of or connected with the pump body, and said valve stem is normally held upwardly or with the valve closed by a spring 111, surrounding a fixed rod 115, also carried by the frame forming a part of the pump body. Said spring exerts a downward pressure on the lever 112 on the opposite side of the fulcrum from-the pivotal connection with the valve stem. Ad'ustment of the tension of the spring is e ected by an adjustable stop preferably in the form of a lock nut and washer 116 on the upper end of the rod 115.

For the purpose of accurately controlling the movement of molten metal under the influence of the pump, and to overcome the tendency of the metal to surge into the passages and pump cylinder, due to the movement of the arts, it has been found necessary to controi the opening and closing movements'of the valve independently of the movement of the pump piston or plunger and while the movements of the valve might be effected through various mechanical agencies associated with parts of themachine which move in proper timed re lation to the movements of the piston and pump parts, it has been found that excellent practical results are attained by operating the valve from the part of the casting machine which also operates the ejector or pusher for discharging the type from the type carrier into the type channel. This ejector orpusher is indicated at 259 in Fig. 1 of the drawing, and the upper end of its operating lever at 333 in Fig. 5. The re- -verse movement of the operating lever is utilized for effecting the opening movement of the valve and the mechanical connections whereby the desired result is obtained embodies a crank shaft 117 journaled in bearings 118 on the frame 2, one arm 119 of said crank shaft being connected through a link or pull rod 120 with the lever 112. The link 120 preferably passes loosely through both the lever 112 and crank arm 119 there being interposed below the crank arm a spring 121 and above thelever 112, an adjustable abutment formed by lock nuts 122, whereby the length of the rod may regulated and the pressure transmitted through the crank shaft is a yielding pressure due to the action of the spring 121, thus preventing any strain or breaking of the parts should the movement of the valve be arrested. The

other arm 123 on the crank shaft is connected by a long link 124 with the lower end of a lever 125 pivotally mounted intermediate its ends on the machine frame, and at its upper end provided with a projection 126 adapted to be struck and moved rearwardly Liy a cooperating projection 127 on the rear and of the rod 332. The projection or arm 127 is preferably clamped between the lock nuts 128 forming the rear abutment ou the rod 332, with whiehthe eye on the end of the lever 333 cooperates to move said rod reversely, and the engagement of the proection or arm 127 with the upper end of the lever 125 preferably occurs during the reverse or rearward movement of the pusher or ejector 259. The range of movement imparted to the lever 125 and valve operated thereby, as well as the position of the lever with respect to the operating arm or proection 127 may be adjusted by varying the point of connection between the lower end of the lever 125 and the end of the link 124, and for this purpose a series of holes 125 are provided in the lower end of the lever, as shown clearly in Fig. 5. 1

Provision is made whereby the link 12-1 may be disconnected from the crank arm 123, as for example, when the pump frame is to be swung away from its operative pos tion, and this may be accomplished by providmg a slot 129 in the end of the link for cooperation with the pin in the end of the crank arm 123 whereby by lifting the link out of engagement with the pin the parts are disconnected and the pump frame may then be swung around in the well understood manner. lVhen the link 124 is disconnected, as above stated, and dropped down along side of the machine frame it naturally falls into position in front of the head for operating the belt shifter 3-14 and will therefore lock the shifter against movement in a direction to inaugurate the opera tion of the machine, thus constituting an automatic safety device for preventing the operation of the machine until the parts are properly connected up for use.

Referring again to Figs. 3 and 4 of the drawing it will be seen that at the base of the nozzle 18 the arm 17 is provided with a chamber 130 in which is located a ball valve 131 which seats downwardly to prevent the flow of metal toward the pump cylinder but which when lifted fromits seat leaves an unobstructed passageway for the flow of metal toward the nozzle. The ball valve 131 is preferably a steel ball, the specific gravity of which is less than that of the molten metal The valve tends to float in said metal and will, therefore, during the time the chamber 130 is filled, fioat at the top of the chamber immediately under the duct extendingup through the nozzle. It is, therefore, in position to be depressed toward its seat by any reverse flow of metal in the nozzle duct and the proportions are preferably such that the valve will move or be moved down to its seat when the metal has drawn back only a short distance in the induction passage, it thus automatically checks the flow of metal and prevents the entry of any great volume of air into or through the induction passages and at the same time the .metal within such passages will be maintained in a molten condition andthe forma tion of a plug of frozen metal prevented by the heat of the surrounding walls of the arm and nozzle. It will be understood thatthis heat is maintained by the immersion of these parts in the molten 'metal of the melting pot, although other means for heating may be employed if .so desired.

In operation, and assuming that the nozzle has been seated in the seatprovided therefor, at the bottom of the mold, and the pump piston or plunger has been operated through its operating mechanism and spring 43, to exert the desired pressure on themetal in the pump cylinder, which pressure is maintained until the metal in the mold is sufficiently hardened or frozen to preventbeing withdrawn, or to prevent it from running out, or that the sprue between the nozzle and mold has hardened sufficiently to'form a dam, the parts are operated to retract the piston or plunger and the nozzle is withdrawn from its engagementwith its seat. This results in a drawback of the. metal in the nozzle, as hereinbefore explained, and almost immediately the valve 107 is opened,-thereby permitting a fresh charge or increment of molten metal to enter the pump cylinder so as to completely fill the latter without a possibility of the entrv of air which would have to be discharged either ahead of or with the metal into the mold at the next casting operation.

While it is believed that the conditions and operation just described are ideal, it may happen in some instances as for example where the type to be cast is ver small, the spring pressure exerted on the plunger will not be relieved until after the valve 107 has opened, in which event there will be a certain portion of the metal forced out of the pump cylinder past the valve 107, preliminaryuto the movement of the plunger, tending to draw metal in to the cylinder. Such action, however, is not detrimental, inasmuch as the operation of the plunger and valve being non-synchronous the flow of metal may be accurately controlled;

While the operation of the piston or plunger of the pump and the opening and closing of the valve are non-synchronous inasmuch as the movements do not begin and end simultaneously, as would be the case were the valve in the intake passage a simple check valve, and while the opening and closing of the valve are practically inde pendent of variation of pressure between the pump cylinder and melting pot due to the piston movements, still the valve itself is a spring-seated valve and might under some circumstances be opened by excessive.

difference in pressure between the melting pot and cylinder. By the cmployment of a spring seated valve the operating mechanism is simplified and the proper non-synchronous timing secured without lost motion or loose connections in the chain of operating connections.

'hat I claim is:

1. In a type casting machine, the combination of a melting pot, a pump having a discharge duct for supplying molten metal to the mold, and an intake duct, a reciprocatory piston in the pump, a .non-return valve in proximity to the end of the discharge duct, a spring pressed intake valve controlling the intake passage. means for reciprocating the piston embodying a yielding connection, and means for opening and closing the intake valve independently of the variation of pressure between, the pump cylinder and melting pot due to the piston movements.

2. A fluid injecting mechanism for type casting machines, embodying a pump having a reciprocatory piston, induction and eduction passages, a check valve in the eduction passage, an intake valve in the induction passage, and mechanicalmeans for operatmg both said intake valve and piston nonsynchronously.

3. A fluid injecting mechanism for type casting machines}embodyinga pump, having induction and eduction passages, a check valve in the eduction passage, with means whereby said valve will be momentarily sustained in an open position to. permit a limited reverse flow in the eduction passage, a reciprocatory piston, an intake 'valve in the induction passagesupported to open inwardly to admit molten metal to the pump andmechanica'l means to operate said intake valve "and piston non-synchronously.

4. A fluidinetalinjecting mechanism for type casting machines embodying a pump having induction and eduction passa es, a reciprocatory piston, an outwardly c osing spring-seated valve in the induction passage, means for reciprocating the piston, and means for opening said valve positively against the pressure of its closing sprin 5. In a type castmgmachme, the combination of the following instrumentalities, to wit: a mold, a pusher for transferring the type cast in the mold, a melting pot, a pump for'injecting fluid metal from the melting pot into the mold and having induction and eduction passages, a reciprocatory piston in the pump, an intake valve in the induction passage of the pump, and connections intermediate said valve and )usher mechanism for opening the valve 'in ependently of the movements of the piston.

6. In a type casting machine. the combination of the following instrumentalities, to wit: a mold, a pusher for transferring the type cast in the mold. operating mechanism for the pusher embodying an operating lever, a melting pot. a pump for supplying molten metal from the pot to the mold having induction and eduction passages, a reciprocatory piston in the pump, an inwardly opening valve in the induction passage, an outwardly opening valve in the eduction passage and operating connections intermediate the valve in the induction passage and operating lever for the pusher, whereby the valve will be opened independently of the reciprocations of the piston.

7. In a type casting machine, the combination of the following instrumentalities. to wit: a mold, a melting pot, a pump for supplying molten metal from the melting pot to the mold having induction and eduction passages, a reciprocatory piston, an inwardly opening, spring-seated valve in the induction passage, a lever connected with said valve for opening the same and operating connections for said lever timed to open said valve independently of the reciprocations of the piston.

8, In a fluid metal in ecting mechanism for type casting machines, the combination of a pump having an induction passage and an eduction passage terminating in an up wardly directed nozzle, a floating check valve located in the eduction passage at the base of the nozzle, and adapted to seat in line with and below the nozzle passage to check the return flow of metal through the eduction passage, a reciprocatory piston in the pump. an inwardly opening valve in the induction passage, a spring for normally holding said valve closed, and means for positively opening said valve non-synchronously with the rearward movements of the piston.

\VILLIAM L. \VALTZ.

\Vitnesses:

KATHRYN E. SEPP, HARRY L. NEFF.