Actuator And Signal Device For A Lifting Magnet

Abstract

An electromagnet-lifting device employed to remove metallic charging hole covers includes a movable actuator member that has a length greater than the thickness of the magnet. When the bottom surface of the magnet is positioned on top of a charging hole cover the actuator is displaced upwardly relative to the magnet and closes a switch in the circuit to energize the magnet and engage the charging hole cover. A relay in the circuit closes a separate switch in another circuit to actuate a signal device that indicates the charging hole cover is engaged by the lifting device.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a signal device for an electromagnet and more particularly to a signal device for indicating the engagement of a lifting magnet to a metallic coking chamber charging hole cover.

2. Description of the Prior Art

Horizontal coking ovens are charged with coal to be coked through vertical charging holes in the roof of the coke oven battery. The charging holes are generally cylindrical in shape and have a relatively heavy unwieldy cover that closes and seals the charging holes during the coking operation. The charging hole covers are removed from the charging holes by electromagnet lifting devices that are suspended from the larry car. It is desirable and often considered essential to indicate either optically or acoustically to the charging machine operator by a signal that the charging hole covers have been lifted by the magnets and the charging holes are open for lowering the feed pipes from the charging larry for feeding the coal charge into the oven chamber.

When the coke oven is being prepared for charging there is a substantial amount of smoke and hot gasses present adjacent the charging holes so that it is difficult for the charging machine operator to determine visually whether the charging hole covers have been removed from all of the charging holes of the coke oven chamber to be charged. Also, the charging machine operator's compartment is usually positioned at a location where it is difficult for the charging machine operator in the operator's compartment to visually observe whether all of the charging hole covers have been removed so that the feed pipes may be positioned in the charging holes.

Presently, indicating apparatus is provided in the cover-lifting magnets for indicating when the charging hole cover is engaged by the lifting magnet. The indicating apparatus includes a magnetically actuated switch that actuates a signalling device. The magnetic switches must be accurately adjusted and at times are inoperative with various charging hole covers because of the different magnetic properties present in the various charging hole covers. Other indicating devices have signaling switches which are operated by eccentric pins of small diameter when the covers are engaged and suspended. The eccentric-type pin is inoperable with a lifting device that includes a cover-turning device for rotating the charging hole cover because the pins jam when the turning device is actuated. Both the magnetically actuated switch and the eccentric switch actuator require a separate circuit from the operator's compartment to a location on the lifting magnet. The separate circuits frequently are damaged by the high temperatures present adjacent the charging holes.

SUMMARY OF THE INVENTION

The instant invention is directed to a signaling device that does not require a separate signal circuit adjacent the electromagnet and is not dependent on a magnetic actuator or an eccentric actuator. The signaling device includes an actuator that is movably mounted on the electromagnet and depends below the bottom surface of the magnet. When the electromagnet is positioned in overlying relation with the charging hole cover, the actuator moves upwardly relative to the electromagnet and closes a switch in the circuit to the electromagnet and thus completes the circuit. A remotely positioned signal device is provided that is responsive to the flow of current in the first circuit to indicate the engagement of the electromagnet to the charging hole cover. The electromagnet is thus not energized until the actuator closes the normally open switch in the electromagnet circuit. With this arrangement a separate circuit to the electromagnet for a signal device is eliminated.

Accordingly, the principal object of this invention is to provide a signal device to indicate the engagement of the electromagnet to a charging hole cover that does not require a separate signal circuit to the electromagnet.

Another object of this invention is to provide an actuator for a signal device that is associated with the electromagnet and is not dependent on either magnetic forces between the switch and the charging hole cover or an eccentric pin-type actuator.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a diagrammatic illustration of the charging hole cover with the electromagnet lifting device positioned thereabove.

FIG. 2 is a view similar to FIG. 1 illustrating the charging hole cover engaged to the electromagnet with the actuator closing switch to complete the circuit and close a second switch in a separate circuit to provide the signal.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and particularly to FIG. 1, there is diagrammatically illustrated a coking chamber 10 having a cylindrical charging hole 12 that extends downwardly into the chamber 10 from the battery roof 14. A metallic charging hole cover 16 is positioned in the charging hole 12 and abuts the annular lip 18 to seal the charging hole 12. The charging hole cover 16 has an upper surface 20 with a circular central opening 22 forming a recess 24. A transverse member 26 is formed in the recess 24 for manually handling the charging hole cover 16.

An annular electromagnet generally designated by the numeral 28 has a body portion 30 with an annular coil diagrammatically illustrated at 32 therein. The body portion 30 has an upper surface 34, a lower surface 36 and a central axial passageway 38. The electromagnet 28 is suspended from the larry car by cables 29 and is arranged to be lowered by the cables onto the upper surface 20 of the charging hole cover 16. A cylindrical actuator 40 is movably positioned in the electromagnet axial passageway 38 and has a bottom wall 42 and a top wall 44. The actuator 40 may be fabricated from various materials, preferably nonmagnetizable materials. The actuator 40 should, however, have sufficient mass or weight to assume the positions illustrated in FIGS. 1 and 2 even when the cylindrical wall of the passageway 38 is coated with carbonaceous dust particles present in the coke oven gas. The actuator 40 has an annular recessed portion 46 adjacent the top wall 44 in which a ring member 48 is positioned. The ring member 48 has a peripheral dimension greater than the dimension of the axial passageway 38 and limits the downward movement of the cylindrical actuator 40 as illustrated in FIG. 1 by abutting the electromagnet upper surface 34. The longitudinal dimension of the cylindrical actuator 40 is greater than the dimension of the electromagnet between the top surface 34 and the bottom surface 36 so that the lower portion of the bottom wall 42 extends below the electromagnet bottom surface 36 when the electromagnet 28 is suspended as illustrated in FIG. 1.

A source of current for a plurality of lifting electromagnets 28 on each larry car is supplied through conductors 50 and 52. A circuit generally designated by the numeral 72 includes branch conductors 54 and 56 that connect the source of current with the coil 32 to supply current thereto. A double pole switch 58 is connected to a switch actuator 60 such as a relay in the operator's compartment. A second switch 62 is provided in conductor 54 adjacent the electromagnet 28. The switch 62 has a housing 64 with an arm 66 extending laterally therefrom. A roller 68 is rotatably secured to the end of arm 66 and is positioned on the upper surface 44 of actuator 40. The switch 62 is normally open and is arranged to be closed by upward pivotal movement of arm 66. A relay diagrammatically illustrated at 70 is actuated by current flowing through the conductor 56. A second signal circuit generally designated by the numeral 74 is connected to conductors 76 and 78 of a second power source and includes conductors 80 and 82. A switch 84 in conductor 80 is also connected to the actuator 60 in the operator's compartment or at a location remote to the electromagnet 28. The connection between actuator 60 and switch 84 is diagrammatically illustrated as a rod and designated by the numeral 86. Thus the operator by means of actuator 60 closes the double switch 58 in circuit 72 and also switch 84 in circuit 74. A second switch 88 in circuit 74 is controlled by the relay 70 in circuit 72 and a signal device 90 is positioned in series with the switch 72 in circuit 74.

With the above arrangement, the operator energizes the actuator 60 which may be a relay or the like to close the double switch 58 in circuit 72 and the switch 84 in circuit 74. Current from the main power source is supplied to the circuit 72 through the conductors 54 and 56. The switch 62, however, maintains the circuit 72 open so that current is not supplied to the coil 32 until the switch 62 is closed. Also, the relay 70 in circuit 72 is deenergized until the circuit 72 is complete by the closing of switch 62.

As illustrated in FIG. 2, when the electromagnet lifting device 28 is lowered into overlying relation with the charging hole cover 16 so that the bottom surface 36 abuts the charging hole cover upper surface 20, the actuator 40 moves vertically upwardly in the axial passageway 38 to thus pivot the arm 66 and close switch 62 to thereby close the circuit 72 and supply current to the coils 32 and exert an electromagnetic force to magnetically engage the charging hole cover 16 to the electromagnet 28.

FIG. 2 illustrates the charging hole cover 16 after it has been magnetically engaged by the electromagnet 28 and lifted by the electromagnet 28 from its covering position, as illustrated in FIG. 1. When switch 62 in circuit 72 is closed, the relay 70 is energized to close the switch 88 in the second circuit 74. Closing switch 88 energizes the remotely positioned signal device 90 to indicate that the charging hole cover 16 is magnetically engaged by the electromagnet 28. Other means can be associated with relay 70 to provide both an audio signal and an interlock with the charging machine when the relay 70 is subsequently deenergized while switch 58 is closed to indicate that the charging hole cover 16 is no longer engaged by the electromagnet 28 as may occur when the charging hole cover 16 is inadvertently released by the electromagnet 28 while the charging hole cover is in a suspended position.

The transverse radial dimension of the actuator 40 is such that positive closing of the switch 62 is assured even though the electromagnet 28 is not centered in relation to the charging hole cover 16 and an edge portion of the actuator 40 is in overlying relation with the recess 24. The radial dimension of the actuator 40 is greater than the radial dimension of the annular opening 22 in the charging hole cover top surface 20. With this arrangement the relay 70 which is connected in series with the coil 32 is positioned at a location remote from the heat present at the coke oven charging hole 12.

If the cover 16 falls during the lifting by the electromagnet 28, the actuator 40 drops downwardly to the position indicated in FIG. 1 and switch 62 is opened to interrupt the supply of current to the electromagnet coil 32. The opening of circuit 72 deenergizes the relay 70 and switch 88 in circuit 74 is opened and the signal 90 is deenergized. Another signal can be transmitted by other actuators in the relay 70 to indicate that the cover has dropped. Also, contacts within relay 70 can interrupt subsequent charging operations until the charging hole cover 16 is again engaged by the electromagnet 28.

It should also be noted with the previously described actuator that it is now possible to turn the charging hole cover 16 without damaging the actuator and the actuator 40 is not subject to jamming in the passageway 38 because of its relatively high specific weight.

According to the provisions of the patent statutes, the principle, preferred construction and mode of operation of this invention have been explained, and what is considered to represent its best embodiment has been illustrated and described.

Claims

I claim:

1. A signal device for an electromagnet comprising,

an electromagnet for lifting a metallic member,

an actuator movably secured to said electromagnet and having an end portion extend beyond a surface of said electromagnet a preselected distance,

a first circuit for supplying current to the coil of said electromagnet,

a first normally open switch in said circuit associated with said actuator,

said actuator operable to move relative to said electromagnet upon positioning said metallic member adjacent said surface a distance less than said preselected distance to thereby close said first normally open switch in said circuit to complete said circuit and supply current to said coil and energize said electromagnet, and

a remotely positioned signal device responsive to the flow of current in said first circuit to indicate the engagement of said metallic member to said electromagnet.

2. A signal device for an electromagnet as set forth in claim 1 in which,

said first normally open switch includes a switch arm having an end portion in overlying relation with said actuator so that movement of said actuator pivots said switch arm to close said first normally open switch.

3. A signal device for an electromagnet as set forth in claim 1 which includes,

a relay positioned in said first circuit,

a second circuit for energizing a remotely positioned signal device,

a normally open second switch in said second circuit controlled by said relay positioned in said first circuit,

said relay operable upon flow of current through said first circuit to close said switch in said second circuit and energize said signal device.

4. A signal device for an electromagnet as set forth in claim 1 in which,

said electromagnet includes an annular body member housing an annular coil and having an axial aperture therethrough,

said actuator includes a rod member movably positioned in said annular aperture and having an enlarged head portion and a bottom end portion extending beyond the lower surface of said electromagnet.

5. A signal device for indicating the engagement of a lifting magnet to a metallic coking chamber charging hole cover comprising,

an electromagnet arranged to be suspended from a larry car for magnetically removing a metallic charging hole cover,

an actuator movably secured to said electromagnet and having an end portion extend beyond the lower surface of said electromagnet,

a first circuit for supplying current to the coil of said electromagnet,

a first normally open switch mounted on said electromagnet and arranged to be closed by said actuator,

said actuator operable to be displaced vertically relative to said electromagnet upon lowering said electromagnet into overlying relation with said charging hole cover to thereby close said first normally open switch in said first circuit and complete said circuit to supply current to said coil and energize said electromagnet, and

a signal device positioned remotely from said electromagnet and responsive to the flow of current in said first circuit to indicate the engagement of said electromagnet to said charging hole cover.

6. A signal device for indicating the engagement of a lifting magnet to a metallic coking chamber charging hole cover as set forth in claim 5 in which,

said first normally open switch is mounted on the upper surface of said electromagnet and includes a laterally extending switch arm with an end portion in overlying relation with said actuator so that upward movement of said actuator relative to said electromagnet pivots said switch arm and closes said normally open first switch.

7. A signal device for indicating the engagement of a lifting magnet to a metallic coking chamber charging hole cover as set forth in claim 5 which includes,

a relay positioned in said first circuit,

a second circuit for energizing a signal device positioned remotely from said electromagnet,

a normally open switch in said second circuit controlled by said relay in said first circuit,

said relay operable upon flow of current through said first circuit to close said switch in said second circuit and energize said signal device.

8. A signal device for indicating the engagement of a lifting magnet to a metallic coking chamber charging hole cover as set forth in claim 5 in which,

said electromagnet includes an annular body member housing an annular coil and having an annular axial aperture therethrough,

said actuator including a cylindrical rod member having a longitudinal dimension greater than the dimension between the top surface and bottom surface of said electromagnet so that said actuator bottom portion extends beyond the bottom surface of said electromagnet,

said actuator having an enlarged top portion that limits downward movement of said actuator.