US3398560A - Control mechanism - Google Patents

Description

1968 M. B. BUNSON ETAL 3,398,560

CONTROL MECHANI SM 4 Sheets-Sheet 1 Filed April 5, 1966 INVENTO/PS MICHAEL E. BUNSON and THOMAS W. WILSON mm kw Attorney 7, 1968 M. B. BUNSON ETAL. 3,398,560

CONTROL MECHANISM 4 Sheets-Sheet Filed April INVENTORS MICHAEL E. ewvson/ and moms w wusou Afiorney 7, 1968 M. B. BUNSON ETAL 3,398,560

CONTROL MECHAN I SM Filed April 5, 1966 4 Sheets-Sheet Z Ill/VENTURE M/Ch'fiEL. E. BU/VSON and THOMAS K. WILSON Alla/nay M. B. BUNSON ETAL 3,398,560

CONTROL MEGHANI SM 4 Sheets-Sheet 4 Hill INVENTORS MICHAEL a. Bur/sow and moms w. wusmv 5y )5% Attorney Aug. 27, 1968 Filed April 5,

United States Patent "ice 3,398,560 CONTROL MECHANISM Michael B. Bunson, McKeesport, and Thomas W. Wilson,

Franklin Township, Westmoreland County, Pa., as-

signors to United States Steel Corporation, a corporation of Delaware Filed Apr. 5, 1966, Ser. No. 540,340 Claims. (Cl. 72-12) This invention relates to an improved mechanism for controlling an article-processing machine in accordance with a dimension of the article.

Although our invention is not thus limited, our control mechanism is particularly useful as applied to a mill for rolling wrought steel wheels for railroad cars. The practice in manufacturing such wheels is to forge a blank to a shape roughly resembling a wheel, and punch an opening through the middle. The outside diameter of the forged blank is several inches smaller than the final wheel diameter. The blank is reheated to a suitable rolling temperature and rolled to its final diameter in a wheel-rolling mill. Reference can be made to The Making, Shaping and Treating of Steel, published by United States Steel Corporation, for a description of a conventional wheelrolling mill. Earlier editions of this publication describe the mill in greater detail than more recent editions. The Fourth Edition, published in 1925, pages 620-633, furnishes a complete description of the mill, as well as of the manufacturing process. The Eighth Edition, published in 1964, pages 729-732, also furnishes a description, but in less detail. Past practice has been for an operator to actuate suitable electric switches manually to initiate various operations of the mill. Although the mill may be equipped with gages which tell the operator when different operations are to take place, the accuracy of timing depends largely on his skill.

In its broader aspects our invention has application elsewhere to control a machine by use of a probe which contacts work in the machine. Mechanisms of this type usually require either a mechanical movement of the probe on making contact, or a flow of electric current through the probe and work. Our control mechanism includes an electronic circuit connected to a probe, whereby mere contact of the probe with the work is sufiicient to effect control of the machine without any appreciable current flow. In this way we avoid hazards incident to exposed conductors which carry electric currents.

An object of our invention is to provide an improved control mechanism for a machine, such as a wheel-rolling mill, which mechanism automatically initiates various operations of the machine on contact with an article processed by the machine.

A further object is to provide a control mechanism of the foregoing type which includes an adjustable probe for contacting the article and an electronic circuit actuated by such contact for initiating operations of the machine.

A more specific object, as applied to a wheel-rolling mill, is to provide a control mechanism which automatically stops advance of the web rolls of a wheel-rolling mill when a wheel blank reaches a predetermined diameter and automatically retracts both the web and rim rolls when the blank reaches a predetermined larger diameter.

In the drawings:

FIGURE 1 is a front elevational view of a wheel-rolling mill equipped with our improved control mechanism;

FIGURE 2 is a horizontal section on line IIII of FIGURE 1;

FIGURE 3 is a front elevational view on a larger scale of the mechanical parts of our control mechanism;

FIGURE 4 is a side elevational view of the mechanical parts on a still larger scale;

3,398,560 Patented Aug. 27, 1968 FIGURE 5 is a vertical section on line VV of FIG- URE 3; and

FIGURE 6 is a schematic wiring diagram.

FIGURES 1 and 2 show a conventional vertical-type wheel-rolling mill which includes a bottom housing 10, a plurality of posts 12 extending upwardly from the bottom housing, and a top housing 13 supported on the posts and spaced above the bottom housing. A friction-driven tread roll 14 is journaled in a slide 15 supported on the bottom housing 10 (FIGURE 2). A screw 16 is connected to the slide. A motor 17, located on the top housing 13, drives screw 16 through appropriate gearing (not shown) and a vertical shaft 19 to adjust the position of the tread roll for wheels of different sizes. A set of opposed web rolls 20 are mounted on spindles 21 which are journaled in bearings 22 pivoted to the bottom housing on vertical axes (FIGURE 2). A motor 23, located on the bottom housing 10 behind the top housing 13, drives spindles 21 through appropriate gearing 24, shafts 25 and flexible couplings 26 to rotate the web rolls (FIGURE 2). Vertical shafts 27 are journaled in the two housings outside the respective spindles 21 and are connected to the spindles through linkages 28. A reversible variable speed motor 29, located on the top housing 13, drives shafts 27 through appropriate gearing (not shown), a screw 31, and linkages 32 to advance and retract the web rolls (FIGURE 1). A bottom set of opposed frictiondriven rim rolls 33 are journaled to horizontally movable carriers 34 mounted on the bottom housing 10 (FIG- URE 1). Similarly a top set of rim rolls 35 are journaled to carriers 36 mounted on the underside of the top housing 13. Pairs of screws 37 and 38 are connected to the respective carriers 34 and 36. A reversible variable speed motor 39, located to the right of the bottom housing 10, drives screws 37 and 38 through appropriate shafts 40 and gearing 41 to advance and retract the rim rolls (FIG- URE 1).

A forged and punched wheel blank W, previously heated to a suitable rolling temperature, is rotatably supported on a loosely fitting mandrel 42. The bottom housing 10 has horizontal slideways 43 in which the mandrel is mounted to enable it to move forwardly as the diameter of the blank expands during the rolling operation (FIGURE 1). The tread roll 14 bears against the circumference of the blank to shape the flange, etc., of the wheel. Motor 23 runs to drive web rolls 20 which bear against the web of the blank to reduce its thickness and expand its diameter. The web rolls also furnish the driving force for rotating the blank and holding it against the tread roll. At the start of a rolling operation, motor 29 runs at a slow speed to pivot the spindles 21 toward each other and thus advance the web rolls with respect to the blank. When the blank expands to a predetermined diameter, motor 29 stops and the web rolls cease to advance, but maintain their position and continue to rotate. All this while motor 39 operates at slow speed to advance the rim rolls 33 and 35 with respect to the blank. After motor 29 stops, motor 39 continues to operate to reduce the rim thickness until the blank reaches its final diameter. Thereafter motors 29 and 39 operate in the reverse direction at an accelerated speed to retract the web rolls 20 and rim rolls 33 and 35 and thus move them quickly out of engagement with the blank. The rolled wheel is removed from the mill for subsequent operations, such as coning and machining. Since the mill and its operation are well known and adequately described in the publication hereinbefore referred to, we oifer no more detailed description here.

Conventionally an operator must determine when the blank W reaches the diameter at which the web rolls 20 should cease to advance and manually actuate an electric switch to stop motor 29. Later he must determine when the blank reaches its final diameter and manually actuate other switches to stop motor 39 and reverse both motors 29 and 39 at an accelerated speed. Our invention affords a control mechanism which automatically initiates these operations.

We attach a horizontal rod 46 to the front of the bottom housing 10 and we pivot a gage arm 47 to this rod. We use adjustable collars 48 to position the arm on the rod, whereby we can move the arm along the rod for different wheel sizes (FIGURE The front of the bottom housing carries a fixed stop 49 which is located inwardly of rod 46 and on which arm 47 rests in its operative position. The back end of arm 47 carries a counterweight 50. We attach an operating handle 51 to the front portion of the arm. Thus by grasping this handle, an operator can lift the arm about its pivotand move it out of the way to enable a wheel blank W to be inserted 1n the mill or removed. The front end of the arm carries a probe holder 52 aligned with the wheel blank W when the arm is in its operative position.

The probe holder 52 carries lower and upper electrical- 1y conductive probes 53 and 54 (FIGURES 3 and 4). Each probe has an insulating sleeve 55 covering the portion which contacts the holder. Our preferred insulating material is a inch layer of epoxy resin reinforced with fiber glass, which can withstand the high temperatures encountered near the hot blank W. We position the lower probe 53 to abut the blank when the blank expands to the diameter at which the web rolls cease to advance. Since the blank continues to expand, we form the probe holder 52 in two sections, the lower of which is pivoted to the upper on a pin 56. We mount the lower probe 53 in the lower section of the holder, whereby it can swing downwardly after it abuts the blank (FIGURE 4). A leaf spring 57 bears against the two sections of the holder to return the lower probe to its operative position when free of a blank. We position the upper probe 54 to abut the blank when the blank expands to its final diameter.

We connect probes 53 and 54 in an electronic circuit arranged as FIGURE 6 shows. The circuit includes two Thyratron tubes 60 and 61, an isolation transformer 62, a plate filament transformer 63, and a number of relays hereinafter identified individually. The circuit of course includes an on-off switch and fuses and may include indicator lights to inform an operator when each step takes place. We have not shown these parts, since their use is well known.

We connect the primary winding of the isolation transformer 62 across lines 64 and 65 leading to a suitable A-C source. We connect the secondary winding of transformer 62 to the primary winding of the plate-filament transformer 63, which has two secondary windings 63a and 63b. We connect opposite ends of the secondary winding 63a with the filaments of both Thyratron tubes 60 and 61 via conductors 66 and 67 to energize the filaments at an appropriate voltage (for example 6.3 volts). We connect one end of the secondary winding 63b with the plate of tube 60 via the coil of a 10,000 ohm platesensitive relay A, a parallel capacitor 68 to prevent arcing, and a resistor 69 in series with the coil. Similarly we connect the same end of the secondary winding 63b with the plate of tube 61 via the coil of a relay B, capacitor 70, and resistor 71. We connect the other end of the secondary winding 63b and the cathodes and screen grids of both tubes 60 and 61 to conductor 67, which is grounded, as indicated at 72.

We apply to the control grids of both tubes 60 and 61 a negative bias which normally blocks flow of current between their plates and cathodes. For tube 60 we extend a conductor 73 from conductor 66 through a blocking diode 74, an adjustable arm 75, any one of a group of sensitivity resistors 76, and a fixed resistor 77, to the control grid. The diode acts as a half-wave rectifier to block positive pulses. Adjustment of the position of arm 75 varies the magnitude of the negative bias on the grid. The circuit also includesa blocking capacitor 78 and a circuit-suppressing capacitor 79 connected as illustrated. The circuit for tube 61 is the same; hence we do not repeat the description We connect the lower probe 53 with resistor 77 via a conductor 83. Similarly we connect the upper probe 54 with the corresponding resistor in the circuit for tube 61 via a conductor 84. The wheel blank W is grounded through the mill, as indicated at 85. When either probe abuts the blank, the corresponding control grid becomes grounded and the negative bias removed, whereupon current flows between the plate and cathode of the tube. When current flows through tube 60, relay A picks up and the plate circuit of the tube is locked in via a contact A and a ground 86. Similarly when current flows through tube 61, relay B picks up and the plate circuit of the tube is locked in via a contact B and ground 87.

Relay A has another normally open contact A in series with the coil of a relay C across lines 64 and 65, whereby relay C picks up with relay A. Relay C has a normally closed contact C in the circuit to motor 29, which contact opens as relay C picks up to stop the motor, whereupon the web rolls cease to advance. Relay B has another normally open contact B in series with the coil of a relay D across lines 64 and 65, whereby relay D picks up with relay B. Relay D has normally open contacts D and D in the circuit to motor 29, which contacts close as relay D picks up to energize the motor in reverse, whereupon the web rolls 29 commence to retract. Relay D has a normally closed contact D which opens as relay D picks up to disconnect the master switch through which motor 29 is actuated manually. Relay D has an additional normally open contact D in series with the coil of a relay E across lines 64 and 65, whereby relay E picks up with relay D. Relay E has a normally open contact E in an acceleration" circuit for motor 29. Relay E has a second normally open contact E in series with the coil of a relay F, whereby relay F picks up with relay. E. Relay F has a normally open contact F in a maximum acceleration circuit for motor 29. Closing of contact E accelerates the retraction of the web rolls 20, while closing of contacts F a moment later further accelerates this movement. We have not illustrated the circuits which energize motor 29, since these circuits are the same as those used when the motor is controlled by conventional manual actuation.

Relay D has further normally open contacts D and D in series with the coils of a relay G and a timedelay relay H across lines 64 and 65, whereby relay G picks up and relay H commences to time as relay D picks up. Relay G has a normally closed contact G1 which opens as relay G picks up to disconnect the master switch through which motor 39 is actuated manually. Relay G has another normally closed contact G in the circuit to motor 39, which contact opens as relay G picks up to stop the motor, whereupon the rim rolls 34 and 35 cease to advance. Relay G also has normally open contacts G and G in the circuit to motor v39, which contacts close as relay G picks up to energize the motor in reverse, whereupon the rim rolls 33 and 35 commence to retract. Relay G has a normally open contact G5 in series with the coil of a relay J across lines 64 and 65, whereby relay J picks up with relay G. Relay J has a normally open contact J in an acceleration circuit for motor 39, which contact closes as relay J picks up to accelerate movement of the rim rolls. The time-delay relay H has a normally closed contact H in series with'the coil of relay G, which contact opens as relay H times out to drop out relay G. Contacts G G and G open to stop motor 39 and drop out relay J. Contacts G and G close to condition the circuit to motor 39 for manual actuation in the forward direction for the next cycle.

We connect a normally open push-button switch 88 in series with the coil of a relay L across lines 64 and 65.

Relay L has normally closed contacts L L L and L, which open as the relay is energized on closing of the switch. We connect contact L between the control grid of tube 60 and the ground 86, and connect contact L between the control grid of tube 61 and the corresponding ground 87. We connect contact L in conductor 83 between the control grid of tube 60 and probe 53, and connect contact L in conductor 84 between the control grid of tube 61 and probe 54. When the web rolls 20 are fully retracted, we momentarily close switch 87, whereupon contacts L L L and L open and disconnect the grounds from the control grids of both tubes. The negative bias is restored and the plate currents cease. Relays A and B drop out, and with them relays C, D, E, F and H. Contacts D D E and F open to stop motor 29. Contact D closes to condition the circuit to motor 29 for manual actuation to start the next cycle. In the event a wheel blank is misshapen or the rolling operation does not take place properly, we can close switch 88 and actuate the master switches manually to control the web and rim rolls.

From the foregoing description, it is seen that our invention affords a simple mechanism for automatically controlling the web and rim rolls of a wheel rolling mill. Control is effected by mere contact between the probes and the work. We avoid any need for mechanical movement of the probes, except to get them out of the way, as well as avoiding any appreciable current flow through the work and the probes. It is also apparent that our invention has broader application than to wheel rolling mills. As already pointed out, the electronic portion of the circuit can be applied generally where it is desired to control without mechanical movement or current flow. We may also use the control mechanism with only one probe, commonly probe 54, and perform the function of the other probe manually.

While we have shown and described only a single embodiment of our invention, it apparent that modifications may arise. Therefore, we do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

We claim:

1. In a wheel-rolling mill which includes means for mounting a wheel blank, opposed web rolls and opposed rim rolls engageable with the blank, and drive means operatively connected with said rolls for advancing them with respect to the blank and thereby reducing its thickness while expanding its diameter, the combination therewith of a control mechanism comprising an electrically conductive probe adapted to abut the blank when it expands to a predetermined diameter, means supporting said probe on said mill, means electrically insulating said probe from said mill, an electronic circuit connected to said probe and actuated by contact of said probe with the blank, and means connecting said circuit with said drive means for reversing the drive means and retracting said rolls when said circuit is actuated.

2. A combination as defined in claim 1 in which said insulating means includes a sleeve of epoxy resin reinforced with fiber glass around said probe.

3. A combination as defined in claim 1 in which said supporting means includes an arm pivotally supported on said mill, a stop fixed to said mill, and a probe holder attached to the end of said arm and carrying said probe, said arm being movable between a position in which said holder is clear of a blank mounted in said mill and a position in which the arm engages said stop, said holder and probe being aligned with the blank when said arm is in the latter position.

4. A combination as defined in claim 1 in which said mechanism further comprises a second probe carried y said supporting means, means electrically insulating said second probe from said mill, said second probe being adapted to abut the blank when the blank expands to a predetermined diameter less than said first predetermined diameter, said second probe being connected to said circuit for actuating the circuit on contact with the blank to stop the drive means which advances said web rolls, but allowing said rim rolls to continue to advance until said first-named probe contacts the blank.

5. A combination as defined in claim 4 in which said supporting means includes an arm pivotally supported on said mill, a stop fixed to said mill, and a probe holder attached to the end of said arm and being formed of uppeer and lower pivotally connected sections, said firstnamed probe being mounted in said upper section, said second probe being mounted in said lower section to pivot out of the way of the blank after it abuts the blank until said first-named probe abuts, said arm being movable between a position in which said holder is clear of a blank mounted in said mill and a position in which said arm engages said stop, said holder and probes being aligned with the blank when said arm is in the latter position.

6. A combination as defined in claim 5 in which said holder includes a spring bearing against said section for holding said second probe in a position to abut the blank until contact is made therebetween.

7. A combination as defined in claim 1 in which said circuit includes a Thyrotron tube, means connected to said tube normally biasing it against conduction, means connecting said probe to said biasing means to remove the bias on contact of said probe with the blank, and a relay connected to said tube to be energized when the tube conducts and having contacts connected to actuate said drive means.

8. A combination as defined in claim 7 in which said probe grounds said biasing means through the blank and through said mill on contacting the blank.

9. In an article processing machine which includes means for mounting an article and means for acting on the article to alter a dimension thereof, the combination therewith of a control mechanism comprising an electrically conductive probe adapted to abut the article when it attains a predetermined dimension, means supporting said probe on said machine, means electrically insulating said probe from said machine, and an electronic circuit connected to said probe and actuated by contact of said probe with the article for terminating action of said machine on the article.

10. A combination as defined in claim 9 in which said circuit includes a Thyratron tube, means connected to said tube normally biasing it against conduction, means connecting said probe to said biasing means to remove the bias on contact of said probe with the article, and relay means connected to said tube to be energized when the tube conducts.

References Cited UNITED STATES PATENTS 2,132,370 10/1938 Hubbard 7287 2,307,191 1/1943 Bell et al. 7287 2,776,585 1/1957 Kendall 7287 3,186,202 6/1965 Ulrych 7287 3,172,311 3/1965 Kendall 7287 RICHARD J. HERBST, Primary Examiner.

Claims (1)

1. IN A WHEEL-ROLLING MILL WHICH INCLUDES MEANS FOR MOUNTING A WHEEL BLANK, OPPOSED WEB ROLLS AND OPPOSED RIM ROLLS ENGAGEABLE WITH THE BLANK, AND DRIVE MEANS OPERATIVELY CONNECTED WITH SAID ROLLS FOR ADVANCING THEM WITH RESPECT TO THE BLANK AND THEREBY REDUCING ITS THICKNESS WHILE EXPANDING ITS DIAMETER, THE COMBINATION THEREWITH OF A CONTROL MECHANISM COMPRISING AN ELECTRICALLY CONDUCTIVE PROBE ADAPTED TO ABUT THE BLANK WHEN IT EXPANDS TO A PREDETERMINED DIAMETER, MEANS SUPPORTING SAID PROBE ON SAID MILL, MEANS ELECTRICALLY INSULATING SAID PROBE FROM SAID MILL, AN ELECTRONIC CIRCUIT CONNECTED TO SAID PROBE AND ACTUATED BY CONTACT OF SAID PROBE WITH THE BLANK, AND MEANS CONNECTING SAID CIRCUIT WITH SAID DRIVE MEANS FOR REVERSING THE DRIVE MEANS AND RETRACTING SAID ROLLS WHEN SAID CIRCUIT IS ACTUATED.

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