US2857820A

US2857820A - Machine for trimming fins from ingot moulds

Info

Publication number: US2857820A
Application number: US499834A
Authority: US
Inventors: Harold M Wilgus; Sola Battista
Original assignee: Valley Mould & Iron Corp
Current assignee: Valley Mould & Iron Corp; VALLEY MOULD AND IRON Corp
Priority date: 1955-04-07
Filing date: 1955-04-07
Publication date: 1958-10-28
Anticipated expiration: 1975-10-28

Description

Oct. 28, 1958 'H. M. WILGUS Em. 2,857,820

MACHINE FOR TRIMMING FINS FROM INGOT MOULDS Filed April 7, 1955 8 Sheets-Sheet l l/arb/a M W/lgl/S Baff/sfa 50/0 M7, Maw/ 19,58 H. M. WILGUS ET AL v 2,857,820

MACHINE FOR' TRIMMING FINS FROM INGOT MOULDS Filed April 7, 1955 8 Sheets-Sheet 2 TO All? SUPPLY (29 ATTORNEYS Oct. 28, 1958 H. M. WILGUS ETAL 2,857,820

MACHINE FOR TRIMMING FINS FROM INGOT MOULDS Filed April 7, 1955 8 Sheets-Sheet 4 I RE'Pl-EN/SH OIL RETURN l l IN V EN TOR. Hare/0 M W// U5 BY Ba/f/s/O $0 a Oct. 28, 1958- H. M. wlLeus ETAL 2,857,320

MACHINE FOR TRIMM INGFINS FROM INGOT MOULDS Filed April '7, 1955 I 8 Sheets-Sheet 6 FEED RE TAA C 7' DRA //v REPLEN/Sh' OIL RE TURN RETURN GAUGE INVENTOR. Hare/a M W// us Buff/5 50 a Oct. 28, 1958 H. M. WILGUS ETAL 2,857,

MACHINE FOR TRiMMING FINS FROM INGOT MOULDS Filed April 7, 1955 8 Sheets-Sheet 7 TO POWER SUPPLY IN V EN TOR. Haro/o M W/ @05 BY Bmf/s fa 50/0 T0 POWER SUPPLY ATTORNEYS Oct. 28, 1958 H. M. WILGUS ETAL- 2,857,820

MACHINE FOR TRIMMING FINS FROM INGOT MOULDS Filed Apri1 7, 1955 s Sheets-Sheet a @Q" 9 F? a? 18.9

' 187T I I 7'0 PO W519 SUPPL Y INVENTOR. f/aro/d M. W/(gu5 PUSH/0N 2 I United States Patent MACHINE FoR TRIMMING FINS FROM INGoT MoULns Harold M. Wilgus, Babylon, N. Y., and Battista Sola, Clitfside Park, N. .1, assignors to Valley Mould and Iron Corporation, Hubbard, Ohio, a corporation of New York Application April 7, 1955, Serial No. 499,834

8 Claims. (Cl. 90-243) This invention relates to a machine for the trim- Ining of fins from cast ingot moulds.

Ingot moulds for the casting of steel ingots are themselves cast from ferrous metal, either -molten iron direct from the blast furnace (direct metal), or cast iron. These moulds are very heavy castings, often having a wall several inches in thickness and a total weight of up to 40 or 50 tons. In the casting of these moulds, the moulding sand may fall away, or the sand mould may become shifted or slightly tilted, or for some other reason, fins are formed on the casting projecting outwardly around the ends of the mould more or less perpendicular to the center line of the mould.- These fins, which are somewhat tapered towards their free edges, are made up partly of metal and partly of .sintered sand, and may extend only part way around one or more sides of the mould. Since such fins will interfere with the functioning of ingot moulds in the casting of steel ingots, it is customary to remove the fins from the mould.

The above-described fins ordinarily have one side lying in the plane of an end of the mould. The fins are trimmed from the mould along a surface which is the general continuation of the outside surface of the mould. It is customary to remove the thinner fins by use of chipping hammers or cold cutters. Thicker fins may be removed by first cutting a scarf along the end surface of the mould and then breaking the fins off along the line of the scarf by impact of a heavy block,

known as a bumping block. Fracturing of the heavier pins requires the use of an overhead crane from which the block is swung.

According to the present invention the fin is cut and broken from the mould by a pneumatic hammer delivering a heavy impact blow, the hammer being mounted on a carriage for both transverse up and down movement. In order to permit the operator to rapidly and accurately trim the fin, the hammer and cutting-tool are automatically positioned and guided responsive to the outside contour of the mould. In trimming fins extending generally horizontally across the top and the bottom of the mould, the vertical position of the cutter is governed by a tracer contacting the outer surface of the mould behind the fin, the traversing movement of the tool along the fin being controlled by the operator. The cutter, which is chisellike and of substantial lateral extent, is mounted for rotation to follow the curved contour of the mould, and when the edge of the cutter extends vertically for trimming the fins from the sides of the mould, the automatic controls operate to move the cutter horizontally, vertical traversing movement of the cutter along the generally vertically extending fins being controlled by the operator.

Among the objects of the present invention are to provide an improved machine for facilitating the trimming of heavy fins from ingot moulds, and to provide such a machine that is rapid and which utilizes automode in which we have contemplated carrying out our I invention is illustrated in the accompanying drawings forming part of this specification, in which:

Fig. 1 is a more or less diagrammatic, isometric view of a machine according to the present invention for trimming an ingot mould, a portion of the mould being shown positioned on racks for trimming.

Fig. 2 is a somewhat schematic longitudinal section of the cutter, air hammer and tracer for severing fins, a portion of an ingot mould being indicated.-

Fig. 3 is a fragmentary top plan view of the cutter controls, including the cam and switches, for controlling the automatic positioning of the cutter. v Fig. 4 is an elevation .of. the control mechanism shown in Fig. 3, a portion of the mechanism being shown in vertical section.

Fig. 5 is a schematic diagram of the hydraulic system for horizontal traverse of the machine and cutter.

Fig. 6 is a schematic diagram of the hydraulic system for vertical traverse of the cutter.

Fig. 7 is a schematic diagram of the hydraulic sys-' tem for advancing and retracting the cutter and air hammer.

Fig. 8 is a schematic wiring diagram of the electrical I by the operator or as required by the contour of I the outside of the mould.

Fig. 9 is a schematic wiring diagram showing connections for the coils of the relays shown in Fig. 8 and the interlock and cam-operated switches necessary to change the automatic control of the positioning of the pneumatic hammer and cutting tool between horizontal and vertical control as the tracer is moved about the outer periphery of the mould.

Fig. 10 is a schematic wiring diagram of the electrical controls for advancing and retracting the pneumatic hammer and cutting tool;

Fig. 11 is a fragmentary diagrammatic view showing a section of the mould, and the tracer head for automatically controlling positioning of the pneumatic ,hammer and cutting tool in accordance with the contour of the outside of the mould.

Referring now to Fig. 1, a portion of a typical mould 12 is shown positioned for cutting a fin therefrom. The mould 12, which often has a wall thickness of several inches and a total weight of up to 40 or 50 tons, is usually cast from direct metal and is cast in a sand mould. Frequently, outwardly projecting fins, such as the fin 14 shown in the drawings, are formed at the lower end of the mould during casting. The fin 14, which may be two inches or more in thickness, is formed partly of the cast metal and partly of sintered sand inclusions from the sand mould. Sometimes it is relatively short and at other times it may extend for most or all the distance about the outside of the ingot mould. One side of the fin 14 is normally in the plane of the end surface 15 of the mould, and the opposite side of the fin may merge with the outer surface of the mould, the fin usually being somewhat tapered towards its outer edge.

The mould 12 is shown positioned on a rack 16 adapted to support the weight of the mould during the tin trim ming operation, only a short section of the rack being shown. Normally, the rack 16 is sufficiently long to support at least several moulds 12 in generally parallel, sideby-side relation. This type of rack for supporting moulds during finishing operations is in general use and is wellknown in the industry.

The mould-trimming machine of the present invention comprises a relatively massive pneumatic hammer 17 for supporting and driving a cutting tool 19. The hammer 17 is supported by a lift frame 2i) which is mounted for vertical movement on a main frame or carriage 21 which is in turn mounted for movement along a pair of horizontal guides or

tracks

2 and 24. The

tracks

22 and 24 extend parallel to the rack 16 so as to permit the machine to be positioned for operating on any mould positioned on the rack. Controls are provided for properly positioning the pneumatic hammer 17 and cutting tool 19 and for operating the hammer and cutting tool, certain of the controls being manual, and certain of the controls being automatic in order to position the tool in response to the outsidecontour of the mould. The various elements of the machine will be described in greater detail hereinafter.

Pneumatic hammer (Fig. 2; see also Fig. 1)

The pneumatic hammer 17 is in most respects the conventional pilot-'valve-operated type, having a multi-part body 25 provided with a stepped bore 26 (Fig. 2). A reciprocating piston or ram 27 is received within the bore 26, portions of the ram being of different diameters to fit the diameters of the bore. The ram 27 is operated by a compressed air supply, preferably furnished at about 100 lbs. 'pfers inch, through an air supply pipe 29 to a pilot-controlled valve 30 of the reciprocating piston type mounted on the body 25 of the hammer.

In general, the operation of the hammer 17 is that air pressure forces a piston-like valve member 31 of the pilotcontrolled valve 30 to one end of a bore in the valve body 32 of the valve, admitting air to one side of the ram 27 so as toforce the ram to move towards the opposite end of the stepped bore 26. As the ram approaches the opposite end of the stepped bore, the ram itself covers certain air passages and uncovers other air passages in the side wall of the bore so as to cause the valve member 31 to be moved by pressure of the incoming air to the opposite end of the valve body so as to change the distribution of air and return the ram for the next blow of the hammer. In general, movement of the valve member 31 always precedes movement of the ram 27. This is more or less conventional in pneumatic hammers of the general type shown.

In the ordinary air hammer, the energy per blow of the ram varies as a square of the maximum velocity of the ram in its power stroke and, therefore, varies generally as a square of the number of strokes per minute of the ram, since the period of the return stroke is not controlled. In such a hammer, the number of strokes per minute of the ram and the energy delivered per stroke are not independently varied. However, in the hammer 17 of the present invention the energy delivered per blow of the ram is largely independent of the number of strokes per minute of the ram, due to a construction to be explained.

The pneumatic hammer 17 has a pair of check valves 34, 34 located in the wall of the smaller diameter portions of the stepped bore 26 and having ball-

type valve members

35, 35, one check valve being located towards each end of the bore and being alternately closed and permitted to open by operating movement of the ram 27. Both ends of the ram 27 are more or less chanifered so as to cause the valve member 35 to ride up on the 4 l ram when the small diameter of the ram passes under the valve members, thus closing valve 34. As the ram 27 returns to the opposite end of the bore 26, the check valve is uncovered and opens so as to vent the end of the piston-like valve member 31 of the valve 30. This arrangement is more or less conventional. However, in the airhammer of the present machine a solenoid-operated valve 36 is interposed in the line between the check valve 34 closed by the ram 27 in its operating stroke (right hand one in Fig. 2) so as to control and, if desired, prevent venting of the air contained in the end of the valve 30 and, therefore, retard or prevent movement of the valve member 31 to that end of the valve body 32, which would initiate a successive stroke of the ram 27.

A pressure relief valve 37 is provided for venting air trapped in the larger diameter portion of the stepped bore 26 when the air has been compressed to a predetermined pressure by forward movement of the ram 27 in its operating stroke. As the ram 27 moves forward in its operating stroke and the larger diameter portion 39 thereof passes the port 40 in the wall of the bore 26, air will be compressed within the end of the larger diameter portion of the bore so as to cushion the operating stroke of the ram in the event that little or no opposition is encountered by the cutting tool 19. The compressed air used for cushioning the ram 27 after retarding or stopping the forward motion of the ram then expands so as to aid in returning the ram for the next succeeding operating stroke. In the hammer of the present invention, the valve 37 is provided to prevent the cushioning air from rising above a certain pressure, thus dissipating energy rather than storing it to be used later in return of the ram 27. In this respect, the pressure relief valve 37 and associated parts of the hammer act as a shock absorber to dissipate energy when there is little opposition to forward movement of the ram. In operation of the hammer when there is much resistance to forward movement of the ram 27 in its operating stroke, the forward edge of the larger diameter portion 39 of the ram will be stopped before closing the port 40 in the bore 26. If there is less resistance to forward motion of the ram 27, the larger diameter portion 39 of the ram will move beyond the port 40, trapping air which Will be more or less compressed so as to cushion the stroke of the ram. If little opposition to the operating stroke of the ram is encountered, the air will be compressed before the portion 39 of the ram to such an extent that the pressure relief valve 37 will open to vent off the excess pressure and thus dissipate energy of the hammer blow.

The volume and pressure of air supplied to the air hammer 17 and, therefore, the energy delivered per blow, is controlled by a throttle valve 41 in the air line 29. Opening the throttle valve 41 admits air to the hammer 17 to institute its operation. In addition, the solenoidoperated valve 42, also in the air supply pipe 29, which is normally closed, opens automatically when the electric circuits for control of the machine (to be described) are energized.

The air supply to the left end of the bore 26 for driving the ram 27 in its power stroke is conducted from the valve 30 through a passage 44, which may be within the wall of the multipart body 25 of the air hammer, and then through a series of external pipes 45 to a port communicating with the bore 26 to the left of the large diameter portion 39 of the ram. A check valve 47 interposed in the line between the port 46 and the air valve 30 provides for forward flow of air, but prevents back flow of exhaust air after the operating stroke of the ram 27.

In addition, an air control valve 49, which is normally open, in the air exhaust line 50, which may be a continuationof the line 45, is operated by air pressure from the line 45 to close the exhaust line, so as to prevent venting'of the. operating air. during the power stroke of theram .27. Air from the air exhaust line. may be utilized to return the cutting tool 19 for the next succeeding blow of the hammer, as will be explained,.a ny excess pressure being vented to atmosphere through a pressure relief valve. 51. i y

The cutting tool 19 is received within an extension 52 of the multipart body 25. The cutting tool comprises a tool bit 54 having a general chisel formation and is mounted in the forward end of a shank 55 which maybe generally rectangular in cross-section. The shank 55 terminates at its inner end in an anvil 56 which may be circular in outline, and is positioned to be struck by the forward endof the ram 27 and driven forward in a bore 57 in a stationary portion 59 of the extension 52 of the multipart air hammer body. A rubber or rubberlike cushion 60 on the back side of the anvil 56 serves to cushion forward movement of the anvil and cutting tool 19 when there is little opposition to forward motion of the cutting tool.

The bore 57 serves as a cylinder and the anvil56 as a piston to return the cutting-tool 19 after each cutting stroke. For this purpose, the air exhausted at the end of each operating stroke of the ram 27 may be utilized,

- the exhaust air being conducted to the backside of the anvil 56 by a line 61. If exhaust air is insufficient to return the cutting tool 19 and anvil56, new air under pressure can also be used.

In trimming a protruding fin 14 from a mould 12, it has been found preferable to maintain the mould stationary andto adjust the position of the cutting tool 19 to follow the contour of the outer surface of the mould. The chisel-like tool bit 54 has a short, straight edge which must be maintained generally coincident with the outer surface of that portion of the mould upon which the tool is operating. Accordingly, the cutting tool 19, including the bit 54, shank 55 and anvil.56 may be rotated about their common axis by means of a rotatable end section 62 of the extension 52 of the hammer body, protruding handles 64 (Fig. 1) being provided for rotation of these parts by the operator.

To provide for automatic adjustment of the position of the cutting tool 19 towards and away from the center of the mould, a tracer arm 65 is provided for following the contour of the outside surface of the mould behind the fin to be trimmed. The tracer arm, which is generally L-shaped, is pivotally mounted on the rotatable end section 62 of the hammer body, the tracer arm locking in the operating position shown in Fig. 2 and also being capable of being swung out of the way, as diagrammatically indicated in broken lines in the drawing.

Preferably, the tracer arm 65 is provided with a heavy cushioning pad 66 extending along the portion ofthe arm confronting the cutting tool 19. The pad 66, which may be formed largely of rubber, serves to prevent damage to the arm from impact of portions of the fin 14 being severed and broken from the mould. The tracer arm 65 has a stylus 67 for following the contour of the outer surface of the mould wall, the operation of the stylus and associated mechanism being described in detail in connection with the automatic controls.

Supporting framework for hammer (Figs. 1 and 2) The pneumatic hammer 17 is supported on a hammer carriage 69 which is provided with four or more rollers 70 for moving the carriage along a pair of carriage guides, one guide 71 being shown. Preferably, the hammer 17 is mounted on the carriage 69 by at least four bolts 68 and springs 73 to cushion vibration of the hammer.

In order to move the hammer 17 and cutting tool 19 towards or away from a mould to be trimmed (advance or retract the tool), the carriage guides 71 are mounted on an operators platform 72 which is supported on the lift frame 20, the guides extending horizontally. A hydraulic cylinder 74 (Fig. 2) is supported by the platform 72 (Fig.1) between the carriage guides 71 and receives a piston (not shown), the piston rod 75 being secured t6 the hammer carriage 69 to move the hammer 17 and cut-. ting tool 19 towards or away from the mould and to press the cutting tool with a predetermined pressure against the fins to be trimmed. V

The operatorsplatform 72, upon which thehammer carriage 69 is supported, is a portion of the lift frame 20. The lift frame 20 has four rollers 76 (three shownin Fig. 1) for mounting the lift frame for vertical movement along a pair of channel-shaped

guides

77, 77, which form a portion of the main frame or carriage 21. A pair of

counterweights

79, 79 connected with the lift frame 20 by

steel cables

80, 80 reeved over

pulleys

81, 81 mounted on the main frame 21 counterbalance most of the weight of the lift frame and the parts supported by it. A vertically extending hydraulic cylinder 82 mounted on the lift frame and a cooperating piston rod 84 mounted on the main frame serve to raise and lowerv the lift frame 20 so as to position the cutting tool 19 at the proper elevation for trimming the fin 14 from the mould.

The main frame or carriage 21 is supported for lateral (horizontal traversing) movement along the horizontal tracks22 and 24 by a series of rollers 85 mounted on the frame, one of the rollers 85 being driven by a hydraulic motor 86 to move the carriage along the tracks. Electric power is supplied to the carriage for powering and controlling the hydraulic system, to be described," by a pick-up consisting of conductors 87, 87 mounted parallel to the track 22 and a pick-up generally designated as. 89 mounted adjacent to the top of the main frame ,or carriage 21. The

tracks

22 and 24 may be mounted on frame work such as a column 90 for supporting the build-'' ing and crane runway. Compressed air for operating the pneumatic hammer 17 may be supplied by a hose (not shown) which is preferably carried on an automatic take-up reel (not shown).

Hydraulic tool positioning systems Positioning of the cutting tool 19 must be susceptible of rapid and precise control. Accordingly, hydraulic systems, which have these desirable operating characteristics, are utilized for horizontal traverse .of the main frame 21 along the

guides

22 and 24, for raising'and lowering the lift frame 20 in the main frame (vertical traverse) and for advancing and retracting the pneumatic hammer 17 with relation to the mould 12. These three hydraulic control systems are indicated more or less diagrammatically in Figs. 5, 6 and 7, respectively, of the drawings, and are housed in ventilated

cabinets

88 and 93 shown in Fig. l.

Horizontal traverse (Fig. 5)

The control system for horizontal traverse of the main frame 21 (Fig. 1) is powered by an electric motor '91 which operates constantly during operation of the machine. The motor 91 drives a variable delivery, reversing pump 92 which pumps fluid to drive the motor 86. The pump 92 may be of the piston-type in which a yoke is moved to control the volume of delivery between zero and a maximum amount and the direction of flow. The position of the yoke (not shown) of the pump 92 is controlled by a stem 94 (Fig. 8). The control of the yoke position will be explained later. I

Flow from the pump 92 passes through a single solef noid-controlled, spring offset, pilot-operated valve 95; The pilot valve spool 96 of the valve 95 is biased to the left as shown in the drawings by a spring 97 except when the solenoid 99 is energized, at which time the valve spool 98 will be moved to the left by the pilot oil pressure so as to close both of'the lines from the motor 86 and interconnect the delivery' and return lines of the pump 92 to unload the pumps and prevent any horizontal creep or movement of the main frame or carriage 21 due to the yoke of the pump 92 not being precisely in the position of zero delivery. The solenoid 99 is energized when the horizontal traverse of the carriage is under map ual control and the control handle (not shown) is in neutral position, as will be explained.

The hydraulic motor 86 for moving the main frame 21 along the horizontal guides 22 and 24 is of the constant displacement piston type, reversing the direction of flow of fluid to the pump. Direction and speed of rotation of the motor 86 and hence the motion of the main frame 21, is controlled by changing the direction of fluid flow and rate of flow delivered by pump 92. At such times as the inertia of the main frame and parts carried thereby causes the motor 86 to rotate at a rate greater than that corresponding to the rate of fluid delivery from the pump 92 a braking force will be applied to the motor by fluid flowing through the combination relief and replenish unit described in the following paragraph. At zero flow of fluid, the motor 86 operates as a brake to hold the main frame 21 against movement.

A combination relief and replenish unit 100 is connected across the fluid lines from the pump 92 to the motor 86 in order to control the braking action of the motor 86, limit the pressure in the system to a safe value, and supply fluid to make up for leakage. The relief and replenish unit 100 includes a pair of adjustable, springloaded

pressure relief valves

101, 101, a pair of

springloaded check valves

102, 102 to prevent back-pressure on the relief valves, and a pair of spring-loaded

check valves

104, 104 for controlling the admission of replenishing fluid. The throttling effect of the

pressure relief valves

101, 101 provides for braking the motor 86. The various parts of the unit are connected as indicated in the drawlugs.

In operation of the horizontal traverse under manual control or when the horizontal traverse is being automatically controlled, as will be explained, the solenoid 99 is not energized and the pilot valve spool 96 is positioned as indicated in the drawings, the speed and direction of rotation of the motor 86 being controlled by the position ofthe yoke of pump 92. When horizontal traverse of the carriage 21 is under manual control but not being moved, the solenoid 99 is energized, the pilot valve spool 96 is at the opposite end of its travel, and the valve 95 is set to interconnect the lines from the pump 92 to unload the pump so as to prevent any fluid being pumped to the motor 86, and, in addition, to close both of the lines to the motor.

Vertical traverse (Fig. 6)

The vertical movement or traverse of the lift frame (see also Fig. 1) within the main frame 21 is accomplished by the hydraulic cylinder 82 and piston rod 84, the cylinder 82 being secured to the lift frame 20 and the ends of the piston rod 84 being secured to the main frame 21. The hydraulic cylinder 82, which is double-acting, not only serves to move the lift frame 20 within the main frame 21, but also serves to hold it in adjusted position against the force of gravity. The

counter-weights

79, 79, previously described, counterbalance in part the weight of the lift frame 20, the parts mounted thereon, and the machine operator, but the counterweights are so chosen so as not to completely counterbalance, and the lift frame is biased downwardly.

The hydraulic system for providing vertical traverse of the lift frame 20 and associated parts is powered by an electric motor 105 which is constantly operating during operation of the machine. The motor 105 is connected to drive a variable delivery reversing pump 106 which may be of the piston type similar to the pump 92 for the horizontal traverse system. The pump 106 may be of the type in which a yoke (not shown) may be moved by a stern 107 (Fig. 8) to control the volume of flow between zero and a maximum and to reverse the direction of flow of fluid from the pump. Operation of the stem 107 will be described hereinafter.

The pump 106 discharges to a single solenoid-controlled, spring offset, pilot-operated valve 109 whichmay be similar to the valve of the horizontal traverse system. A solenoid 110 and spring 111 control the position of a pilot spool 112 which in turn controls the flow of fluid pressure from a pilot fluid supply line 114 so as to actuate a valve spool 115 which controls the flow of fluid pressure to the hydraulic cylinder 82.

A combination relief and fluid replenish unit 116, which may be similar in all respects to the unit 100 previously described in connection with the horizontal traverse mechanism, is connected between the fluid lines to the hydraulic cylinder 82 and functions similarly.

As above described, the piston rod 84 is affixed to the main frame 21 and, therefore, the rod and a piston 117 mounted thereon are not moved vertically. Instead, the hydraulic cylinder 82, which is secured to the lift frame 20, is raised or lowered by fluid pressure within the ends of the cylinder. As above mentioned, the weight of the lift frame 20, the parts carried thereby and the machine operator isnot completely counterbalanced and, there fore, the lift frame 20 and cylinder 82 are biased downwardly due to gravity. To avoid downward creep of the lift frame 20 due to leakage in the vertical traverse fluid system as a whole, a pilot operated check valve 119 is connected between the fluid lines to the cylinder 82, and a counterbalance valve 120 is connected into the line from the top of the cylinder 82 and beyond the valve 119. The pilot operated check valve 119 includes a spring-pressed check ball 121 which normally prevents fluid from flowing from the cylinder 82 above the piston 117 so as to prevent the lift frame 20 from slowly settling. Upon fluid pressure being applied to the fluid line leading to the cylinder 82 below the piston 117, a piston member 122 is forced upwardly to unseat the check ball 121 so as to open a passage from the cylinder 82 above the piston 117. Further increase inpressure in the line from the top of the cylinder 82 will raise the valve spool 124 of the counterbalance valve 120 so as to permit the fluid to flow from the upper part of the cylinder 82 and thereby lower the 'lift frame 20.- On the other hand, fluid pressure applied in the opposite direction will unseat the check ball 123 of the counterbalance valve 120 and then directly displace the check ball 121 and fluid will flow into the upper part of the cylinder 82 so as to raise the lift frame 20.

Tool feed (Fig. 7)

The hydraulic system for feeding and retracting the pneumatic hammer 17 and cutting tool 19 includes an electric motor 125 which operates at all times that the machine is being used and drives a two-pressure, fixed displacement pump unit 126 which may be of the vane type. A first pump 127, having a smaller displacement, and a second pump 129, having a larger displacement, are connected in parallel with a check valve connected between the discharge lines of the two pumps to prevent flow of fluid from the discharge line of the first pump 127 to the discharge line of the second pump 129 but to permit reverse flow. An unloading valve 131 acts to unload the second pump 129 when the pressure exceeds a fixed amount, e. g. 200 p. s. i., so as to return the fluid from the pump 129 to the oil supply. The organization is such that at pressures below the operating pressure of the unloading valve 131, the

pumps

127 and 129 are pumping in parallel, the check valve 130 remaining open. At pressures above the operating pressure of the unloading valve 131, the second pump 129 will be unloaded and the check valve 130 will close to prevent unloading of the first pump 127. A pressure relief valve 132 in the discharge line of the pump 127 limits the pressure in the hydraulic system to a safe amount.

The discharge line from the first pump 127 then leads to a volume control unit 134 for controlling the flow of hydraulic fluid so as to maintain the flow constant at any set value within the range of the control, independent of load resistance variations within the range covered by the setting of pressure control valve 137. The unit 134 entering and exit sides of a rotatable flow control plug 136 so as to maintain a constant pressure difference across the flow control plug and, therefore, a constant flow rate for a given setting of the control plug. Rotation of the'plug 136 to enlarge or restrict the passage will vary the volume of flow. Excess volume of flow delivered from the pump unit 126 is discharged either through the pressure relief valve 132 or the pressure control valve 137, to be described.

The flow of fluid from the unit 134 discharges to a pilot-operated valve 139 having a double solenoid, springcentered pilot spool 140. A left hand solenoid 141.is actuated to move the pilot spool 140 to the right in the oriented position shown in the drawings, which will cause the pilot oil supply to move a valve spool 142 of the valve to the left so as to direct the fluid flow to the right hand end of the cylinder 74 to move the piston rod 75 to the left and retract the hammer 17 and cutting tool 19 away from the mould 12. On the other hand, ener gizing the right hand solenoid 144 causes the pilot oil supply to displace the valve spool 142 to the right so as to direct the fluid flow to the left end. of the cylinder 74 to move the' piston rod 75 to the right for. tool feed. When neither solenoid is operated, the valve spools 140 and 142 are in mid-position and the hydraulic fluid flows through a check valve 145 which serves to maintain the hydraulic pressure in the system somewhat above atmospheric pressure. With the valve spool 142 in midposition, thelines to both ends of the cylinder 74 are closed and the hammer 17 is heldagainst either feed or retraction.

A relief and replenish unit .146 is connected between the two lines leading from the pilot-operated valve 139 to the ends of the cylinder 74, the function of the unit 146 being similar to that of the

units

100 and 116 previously described.

p The discharge line from the first pump 127 also connects with the pressure control valve 137 to provide for adjustment of the maximum pressure developed by the first pump 127. The control valve 137 comprises a spool 143, the position of which is controlled by the pressure developed by the first pump 127 applied to the bottom of the spool and the pressure at the outlet of a pressure regulator valve 152 (to be described) applied at the top of spool 143. The pressure delivered by the pressure regulator valve 152 to the top of spool 143 will determine the pressure at which the pressure control valve 137 will open and relieve the pressure developed at the outlet of the first pump 127. 7

An impact control switch unit 147 is connected to the fluid line to the left or feed side of the cylinder 74, this line being the high-pressure line when driving the piston rod 75 to the right for tool feed. The impact control switch unit 147 is connected through a flow restrictor 149 which serves to dampen out rapid pressure fluctuations between the line to the left end of the cylinder 74 and the switch unit 147. .The impact control switch unit 147 includes a spool 15% which operates an electrical switch 151 controlling, operation of the pneumatic hammer 17. The pneumatic hammer 17 is so arranged as to be inoperative unless the switch 151 is closed, as will be explained.

The position of the spool 150 is determined by the pressure in the line to the left end of the cylinder 74 balanced against the pressure within the upper portion of the impact control switch unit 147. The upper portion of the switch unit 147 is connected to the pilot oil supply through an adjustable pressure regulator valve.152 to provide for the electrical switch 151 to be closed at a tool pressure on the mould adjustable from 270 to 2245 lbs., determined by adjustment of the pressure regulator valve 152. The areas of the pressure control valve 137 and impact control switch unit 147 on which the various fluid pressures act are designed so that the electrical. switch 151 closes at approximately of the fluid pressure at which the control valve 137 operates to relieve the pressure developed by the first pump 127. A bleed orifice 148 allows a constant small flow of fluid through the pressure regulator valve 152 to stabilize its operation. I

The pilot oil supply and replenish oil for the entire hydraulic system may be combined and supplied by a pump (not shown) at a pressure of p. s. i., the

check valves in the replenish units requiring 65 p. s. i. to operate. The various oil drains of the system serve to return the oil to a common sump from which it is pumped by the various pumps.

Control of cutting tool position (see particularly Figs. 11, 4, 3, 8 and 9) draulic systems is controlled by an electrical control system, to be described.

Referring to Fig. 11, a diagrammatic cross-section of a typical rectangular mould 12 is shown having a marginal fin 14 to be trimmed. As above mentioned, in trimming the fin 14 it is imperative that the cutting tool 19 follow closely the outside surface of the mould. Since the mould is generally rectangular in cross-section and is resting on the rack 16 (Fig. 1) which extends horizontally, two sides of the generally rectangular mould 12 will extend generally horizontally and two sides will extend generally vertically. The corners of the mould 12 are somewhat rounded. In following the cutting tool 19 along the outer surface of the mould 12, the cutter will be moved sidewise of itself after each blow or group of blows that servea particular section of the fin. The amounts of the sidewise movements (horizontal movement in trimming the fins at the top and bottom inFig. 11, and vertical movement in trimming the fins at the sides in Fig. 11) need not be precise, since insutficient traverse of the cutter will only make for slower cutting, and too great traverse after serving a section of the fin will only skip over the adjacent section of the ly positioning the cutter towards and away from the center of the mould (operating in vertical direction in trimming the fins at the top and bottom in Fig. 11 and operating in horizontal direction in trimming the fins at the two sides in Fig. 11) is provided.

This automatic control includes the tracer arm 65, previously described in connection with Fig. 2, having the stylus 67 for following the contour of the outer surface of the mould. As above described, rotation of the end section 62 of the pneumatic hammer 17 rotates the cutting tool 19 and also the tracer arm 65. gear 154 (Fig. 4) mounted on the shank 55 of the cutting tool is rotated with the cutting tool so as to rotate a second gear 155 which through a pair of

intermeshed gears

156 and 157 drive a cam shaft 159, rotation of the cuttingtool 19 causing a corresponding rotation of the shaft 159. A cam 160, aflixed=to the cam shaft 159, actuates switches, to be described, for determining whether the tracer arm 65 and its stylus control vertical or horizontal movement of the cutting tool, and whether in moving the cutting tool 19 in towards the center of the mould, the tool is moved downwardly or upwardly, or to the left or to the right.

As previously described, the tool 19 is moved vertically or horizontally by the vertical and horizontal tool positioning hydraulic systems.

Horizontal traversing movement is controlled by the position of the yoke of the variable delivery reversing pump 92 (Fig. 8), and vertical traversing movement is controlled by the position of the yoke of the variable delivery reversing pump 106 (Fig. 8). The electrical controls, to be described, operate on these two pumps to control the rate and di rection of flow of hydraulic fluid therefrom.

Referring to Fig. 8, a horizontal traverse servo group 161 includes a servo motor 162, which may be of the two-phase, low inertia motor and gear reducer type fed from an amplifier 164 which may be of either the magnetic or electronic type. The amplifier 164 is fed from a pair of potentiometers. One of the pair isa feed back potentiometer 165 always in circuit to the input of the amplifier 164, and the other potentiometer in the circuit with the input of the amplifier is determined by the position of the tracer arm. The slider of the potentiometer 165 is connected to and moved by control stem 94 in such a manner that when the yoke of the variable delivery reversing pump 92 is in zero delivery position, the slider of the potentiometer 165 is in the center of the potentiometer resistance.

Assuming that horizontal traverse of the cutting tool 19 (which includes bit 54) is under manual control, the potentiometer166 will be connected with the feed back potentiometer 165 and the amplifier 164 by a triple-pole double-throw magneticrelay 167. The potentiometer 1 66 is manually operated, as by a lever (not shown) to position the slider of the potentiometer. Any movement of the slider of the potentiometer 166 from mid-position will produce an electric current to the amplifier 164. The amplifier 164 will cause the servo motor 162 to change the position of the yoke of the pump 92, and likewise move the slider of the potentiometer 165 to a position corresponding to the position of the slider of the potentiometer 166. If initial movement of the servo motor 162 is insufiicient or excessive, the different positions of the sliders of the

potentiometers

165 and 166 will correct its position. Accordingly, when horizontal traverse is under manual control, the slider of the feed back potentiometer 165 will always follow the position of the slider of the potentiometer 166, thus positioning the yoke of the variable delivery reversing pump 92 to discharge fiuid at a rate proportional to, and in the direction determined by, the displacement of the slider of potentiometer 166 from its mid-position.

The vertical traverse servo group 169 is similar to the horizontal traverse servo group 161 and controls the variable delivery reversing pump 106. This group includes a servo motor 170, an amplifier 171 and a feed back potentiometer 172. When the vertical traverse of the cutting tool 19 is under manual control, the servo group 169 is connected through a 3-pole double-throw relay 175 to a potentiometer 174 which is manually operated, as by a lever (not shown). The operation of the servo group 169 for vertical traverse is similar to the operation previously described of the servo group 161 for horizontal traverse.

The tracer arm 65 carries a stylus 67 (previously described) which operates a potentiometer 176 built into the tracer arm. The potentiometer 176 has the same resistance as the potentiometers of the

pairs

165, 166 and 172, 174 previously described. The cutting edge of the tool bit 54 (indicated in Fig. 8) is aligned with the mould-contacting end of the stylus 67 when the slider of the potentiometer 176 is at mid-point, at which point the position of the slider of the potentiometer 176 corresponds with the position of the yokes of the variable delivery pumps 92 and 106 for no delivery. In addition, a potentiometer 177, similar to

potentiometers

174 and 166 previously described, is associated with the automatic cutter positioning control.

A pair of 3-pole, double-

throw relays

179 and 180 serve to selectively connect the potentiometers 176 and p 177 with either the servo group 161' or 169, the potentiometer 176 being connected with the vertical traverse servo group 169 in trimming the top and bottom of the mould (

positions

1 and 3 of Fig. 11), and the potentiometer 177 being connected with the horizontal traverse servo group 161 during such positions. In trimming the sides of the mould (positions 2 and 4 in Fig. 11), the potentiometer 176 is connected with the horizontal traverse servo group 161 and the potentiometer 177 is connected with the vertical traverse servo group 169.

A 3-pole, double-throw relay 181 in the lines from the potentiometer 176 serves to reverse the action of the vertical traverse servo group 169 when the tracer arm is inverted (i. e., shifted from position 1 to position 3 in Fig. 11), and to reverse the action of the horizontal traverse servo group 161 when the position of the tracer arm is reversed (i. e., shifted from position 2 to position 4 in Fig. ll).

The wiring diagram for the operating windings of

relays

167, 175, 179, 180 and 181 is indicated in Fig. 9. In all tracer arm positions when under automatic operation, relays 167 and are energized so as to disconnect the

servo groups

161 and 169, respectively, from the

manual control potentiometers

166 and 174. In

tracer arm positions

1 and 3, relays 179 and 180 are not energized, and in tracer arm positions 2 and 4 these two relays are energized. The vertical traverse servo group 169 is connected for automatic control when these two relays are not energized, and the horizontal traverse servo group is connected for automatic control when these relays are energized. The reversing relay 181 is energized for tracer arm positions 3 and 4 only. In addition, a normally open, double-pole, single-throw relay 182 (see Fig. 9) serves to simultaneously operate

relays

179, 180 and 181 in tracer arm position 4. Energizing these various relays according to

tracer arm positions

1, 2, 3 and 4 is accomplished in response to rotation of the end section 62 of the hammer, section 62 carrying the tracer arm 65 and the rotation of section 62 being transmitted to cam 160 as explained in connection with Fig. 4 under the heading Control of Cutting Tool Position. The cam 160 has a lobe extending for about 90, which is shown in Fig. 9 in the position corresponding to tracer arm position 1. As the tracer arm 65 is rotated in either direction past 45, cam 160 operates successive switches controlling the energizing of

relays

179, 180, 181 and 182. The first switch is a single-pole, doublethrow switch 184 located so as to be operated by the leading edge of the cam lobe (coinciding with zero degree line, Fig. 9) as the tracer arm 65 is moved across the

line separating positions

1 and 2 of Fig. 11. The second switch is a single-pole, double-throw switch 185 which is operated by the leading edge of the lobe of cam 160 as the tracer arm 65 is moved across the

line separating positions

2 and 3 of Fig. 11. The third and last switch is a normally open, single-pole single-throw switch 186 which is similarly operated by the earn 160 as the tracer arm is moved across the line separating positions 3 and 4.

Relays

167 and 175 are energized by swinging the tracer arm 65 into operable position, indicated in Fig. 2. Preferably, a series of two single-pole, single-

throw switches

187 and 189 in the circuit to these relays are closed, one switch being closed by swinging the tracer arm 65 in operable position and the other switch being closed by locking it in position. In addition, a normally closed, single-pole, single-throw switch 190 in series with the

switches

187 and 189 may be provided for opening the circuit to

relays

167 and 175 whenever it is desired to have manual control of both the vertical and horizontal traverse at such times as the tracer arm 65 is locked in operating position.

Control of tool feed (Fig. J 0; see also Figs. 2 and 7) The electrical circuit for control of the tool feed hydraulic system serves to open the air supply pipe 29 to the pneumatic hammer 17 whenthe control circuits are energized,-to feed, stop or retract the cutting tool 19 and to operate the pneumatic hammer 17 either manually when-desired or automatically when the tool contact pressure attains a predetermined amount. This system, which is energized at all times that the control system is energized, includes the solenoid controluvalve 42 in the air supply line 29, the valve 42 being normally closed and being opened to supply air to thehammer upon energizing the control circuit and mechanism. In addition, the hammer control circuit includes the

solenoids

144 and 141 of the pilot operated valve 139 controlling feeding and retraction of the cutting tool 19. A normally closed, single-pole, single-throw stop switch 191 in series with the solenoids of the pilot-operated valve 139 serves, when opened, to stop all motion of the tool feed system. In addition, a single-pole, double-throw switch 192 controls the tool feed. The switch 192 is biased to retract the cutting tool 19, but when depressed will advance the tool. In addition, a normally closed, single pole, single-throw switch 194 serves as a limit switch to open the circuit to the solenoid 141 when the pneumatic hammer 17 and its associated parts are in fully retracted position.

The solenoid control valve 36 (previously described) which is normally closed and which controls venting of the end of the chamber of the valve member 31 so as to control operation of the hammer 17, is connected in series with the pressure operated switch 151 so as to energize the solenoid 36 and open the valve to cause operation of the hammer whenever the tool pressure has reached the predetermined amount. In addition, a normally open, single-pole, single-throw switch 195 may be depressed so as to energize the solenoid and open the valve 36 to operate the pneumatic hammer 17 even though the tool pressure is below the predetermined amount. A single-pole, double-throw switch 196 of the maintaining contact button type permits choice of either manual or automatic operation of the hammer.

Miscellaneous In trimming the fin 14 from the curved portions of the mould 12 connecting the horizontal and vertical walls of the mould as positioned in Fig. 11, the automatic control of the positioning of the cutting tool 19 will operate to traverse the tool vertically until such a time as the tool is rotated 45 in either direction from position 1, at which time the automatic control will operate to traverse the cutting tool horizontally. Likewise, in trimming the fin from a generally circular mould, the controls will work similarly.

The method and machine herein described provide for the rapid trimming of fins from various sizes of ingot moulds, the positioning of the cutting tool and the operation of the cutting tool being in large part under automatic control, but at the same time being under the immediate, overriding control of the machine operator.

We claim:

1. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing laterally projecting fins from the outer surfaces of said moulds, said machine comprising a power-driven, reciprocating, chisel-like cutter mounted for both horizontal and vertical traverse, a tracer for following the contour of the outer surface of the mould on the opposite side of the fin from the cutter and having a mould-contacting portion generally aligned with the cutter, said cutter and tracer being mounted for simultaneous rotation about an axis extending in the direction of reciprocation of the cutter, means for traversing the cutter both horizontally and vertically, means for controlling traverse of the cutter in one of such directions in response to contour of that portion of the mould surface contacted by the tracer, and means for shifting the traverse control means between 14' control of vertical traverse and control of horizontal traverse as the cutter and tracer are rotated. H I

. 2. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing. laterally projecting fins from the outer surfaces of said moulds, said machine comprising a power-driven, reciprocating chisel-like cutter mounted for both horizontal and vertical traverse, a tracer for following the contour of the outer surface of the mould on the opposite side of the fin from the cutter and having a mould-contacting portion gen-- erally aligned with the cutter, said cutter and tracer being mounted for simultaneous rotation about an axis extending in the direction of reciprocation of the cutter, hydraulic means for traversing the cutter both horiz0ntally and vertically, means for controlling traverse of the cutter in one of such directions in response to contour of that portion of the mould surface contacted by the tracer, and means for shifting the traverse control means between control of vertical traverse and control .ofhori zontal traverse as the cutter and tracer are rotated.

3. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing laterally projecting fins from the outer surfaces of said moulds, said machine comprizing a power-driven, reciprocating chisel-like cutter mounted for both horizontal and vertical traverse, a tracer for following the contour of the outer surface of the mould on the opposite side of the fin from the cutter and having a mould-contacting portion generally aligned with the cutter, said cutter and tracer being mounted for simultaneous rotation about an axis extending in the direction of reciprocation of the cutter, hydraulic means, including variable delivery pumps and fixed displacement hydraulic motors, for traversing the cutter both horizontally and vertically, means for controlling traverse of the cutter in one of such directions in response to contour of that portion of the mould surface contacted by the tracer, and means for shifting the traverse control means between control of vertical traverse and control of horizontal traverse as the cutter and tracer are rotated.

4. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing laterally projecting fins from the outer surfaces of said moulds, said machine comprising a power-driven cutter mounted for both horizontal and vertical traverse, and means for controlling traverse of the cutter in one of such directions in response to contour of the outer surface of the mould on the opposite side of the fin from the cutter.

5. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for'severing laterally projecting fins from the outer surfaces of said moulds, said machine comprising a power-driven, reciprocating, chisel-like cutter, means for rotating the cutter to follow the contour of the outer surface of the mould, means for traversing the cutter horizontally, means for traversing the cutter vertically, and means for controlling operation of one of the cutter-traversing means in response to contour of the outer surface of the mould on the opposite side of the fin from the cutter, and for shifting said control between horizontal and vertical as the cutter is rotated.

6. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing laterally projecting fins from the outer surfaces of said moulds, said machine comprising a power-driven, reciprocating, chisel-like cutter mounted for both horizontal and vertical traverse, a tracer for following the contour of the outer surface of the mould on the opposite side of the fin from for traversing the cutter both horizontally and vertically,

means for controlling traverse of the cutter in one of such directions in response to contour of that portion of the mould surface contacted by the tracer, means for shifting the traverse control means between control of vertical traverse and control of horizontal traverse as the cutter and tracer are rotated, and means for reversing the direction of traversing movement under control of the mould contour when the tracer is rotated to a generally opposite position.

7. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing laterally projecting fins from the outer surface of said moulds, said machine comprising a power-driven reciprocating cutter, means for traversing the cutter towards and away from prolongation of the outer surface of the mould by movement in a direction perpendicular to the direction of cutter reciprocation, means for advancing and retracting the cutter towards and away from the fin by movement in the direction of cutter reciprocation, and means to render the cutter inoperative unless the cutter is positioned against the fin to be cut.

8. In the art of finishing cast ingot moulds for the casting of steel ingots, a machine for severing laterally projecting fins from the outer surface of said moulds,

said machine comprising a power-driven reciprocating References Cited in the file of this patent UNITED STATES PATENTS 1,760,354 Gartin May 27, 1930 2,028,053 Errig Ian. 14, 1936 2,074,257 Ernst et a1 Mar. 16, 1937 2,151,078 Bouvier Mar. 21, 1939 2,681,595 Le Compte June 22, 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,857,820 October 28, 1958 Harold M, Wilgus et a1 It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 45, for "pins" read fins line 50, after "transverse" insert and column 10, line 42, for "serving" read 'severing Signed and sealed this 10th day of February 1959.

SEAL) ttest:

KARL Itx AXLINE ROBERT c. WATSON Attesting Oflicer Commissioner of Patents