US1325914A - Lifting-magnet - Google Patents

Description

' L. D. ROWELL.

LIFTING MAGNET.

APPLICATION FILED OCT. 7, 1907.

1,325,914. Patented Dec. 23,1919.

5 SHEETS-SHEET l- Z7 Z2 Z1 3 Mm E 6 film a a? L. D. HOWELL.

LIFTING MAGNET.

IIIIIIIIIIIIIIIIIII 7. I907- 1,325,914; Patented Dec. 23,1919.

5 sssssssssss T g.

waif/e5 L. D. HOWELL.

LIFTING MAGNET.

A CATION FILED OCT. 7. I907. 1,325,914. Patented Dec. 23,1919.-

5 EEEEE S' EEEEE 3.

wing/fab gmwmm 4 ns L. D. HOWELL.

LIFTING MAGNET. APPLICATION FILED OCT. 7, 1901. 1,325,914. 7 Patented Dec. 23,1919.

5 SHEETSSHEET 4- |lllllllllllilllllllillll||"mm"llI Q (X /275 K I I L. D. ROWELL.

LIFTING MAGNET. I APPLICATION FILED OCT. 1. I90].

I 1 325,9 1 4. Patented D60. 23, 1919.

5 SHEETSSHEET 5.

, UNITED STATES PATENT OFFICE.

LEWIS 1). owen,

0F MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO THE CUTLER-HAMMER MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION or WISCONSIN.

, LIFTING-MAGNET.

I Specification of Letters Patent.

Patented Dec. 23, 1919..

Applicationfiled October 7, 1907. Serial No. 896,187.

'useful Improvements in Lifting Magnets,

of which the following is a full, clear. con; cise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to lifting magnets. 'One of the objects of the invention is to provide a lifting magnet which will readily withstand the shocks and strains to which it is subjected.

Another object is to provide a lifting magnet which will have a large lifting power for its size and weight.

-Another object is to provide a lifting magnet in which the energizing winding is thoroughly protected.

Another object is to provide an efficient magnet which will stand severe service and not require constant. repair.

Another object. is to provide a lifting magnet which will cause its load to be concentrated as it is released.

Various other objects and advantages will hereinafter appear.

1 The accompanying drawings illustrate an embodiment of the invention, and in said drawings:

, t Figure I is a cross-sectional viewon the line 11, Fig. III,

Fig. II is a horizontal sectional view on the line 2-2, Fig. I. e

Fig. III is a bottom plan view with the outer parts broken away to expose the interior parts,

Fig. IV is a sectional view on the line 4, Fig. I, showing the terminal housing.

' Fig. V is a plan View of the energizing coil with one of the outside insulating disks removed,

Fig. VI is a side view of the coil,

Fig. VII is aperspective view-looking at the inside of two adJacent inner sections of the ener izing coil,

Fig: III is a pig-iron,

Fig. TX is a similar view showingit at,- tracting a large plate, and

energizing winding.

I diagrammatic cross-,seo tlonal vlew of the magnet showing it lifting, V

' Manner pole view showing the magnet liftin a l-ar e plate and having an adapter applied to t e inner pole to eliminate the air gap between the inner pole and he plate. i The magnet has a cast steel frame 11 provided with a central or inner pole piece 12, and an outer pole iece 13. Between the outer and inner p0 e pieces-is an annular channel or recess 14; in which is located the energizing winding 15.

The outer periphery of the frame is provided with axial corrugations 16 which merge into radial corrugations 17, on the top of the frame. crease the radiating surface of t e .magnet. The magnet frame is further provided with a central opening or aperture 18 through which air may circulate to assist in cooling the magnet, and the walls'of this opening serve to increase the radiating surface.

' Eye-bolts 19 are preferably threaded into the top of the frameand chains 20 are attached to these eye-bolts for suspending the magnet. 1

Over the annular recess 14 is placed a non-magnetic circular cover plate or ring 21, which covers supports, and protects the This cover plate is provided at its oute wardly extending flange 22, and radial ribs 23 extend across the lower face of the cover plate to strengthen it.

The inner'pole piece 12 carries a ma netic pole shoe 24: which is held in place by means of bolts 25, threaded into the inner pole piece. This pole shoe is provided with a central opening 26, which communicates with a central openingin the magnet frame. The outer pole piece 13 is provided with a magnetic pole shoe 27, which is in the form of a ring, and is held in place by means of through-bolts 28. The heads of the bolts set on a flange formed on the pole piece 13 and are arranged'in the indentations between the corrugatlons 16, so as to be protected from injury. The nuts of the bolts are set in notches formed in the pole shoe 27 and are thus protected from injury, The cover plate 21 is held in place by means of the inner pole shoe 24 and the outer pole shoe 27, the

shoe beingformed with a shoulder-gin its outer periphery upon which the inner periphery of the cover plate rests, and

Fig, X is a diagrammatic eross-aectiomtlgJE 7 Ole $11 6.27 b9ii g provided with a r edge with a dowli-- These corru ations' inv shoulder in its inner periphery upon which I tom 0 I I The pole shoes are rigidly mounted upon their respective pole pieces-and directly or closely engage these pole pieces so that the the flange 22 of the cover plate rests, said flange alsm engaging the inner periphery of the pole piece 13. The flange 22 thereby prevents lateral movement of the pole shoe 27. The lateral-support thus provided relieves. the shearing strain on the bolts 28 when-the magnet is in use. It also aids 1n making the magnet a solid,'compact structure. j

The outer pole shoe 27 is made thick and rugged to withstand the shocks and strainsto which it is subjected. It projects downwardly sufiici'ently to ordinarily engage the materlalto be lifted before any other part of the magnet. It also extends downwardly a sufiicient distance to protect the'winding:

The outer pole piece 13 and its pole shoe 27 form an outerpole having its polar face atthe bottom of the outer ,shoe. The inner pole piece 12 and its pole. shoe 24 form an inner ole having its polar face at the botf the inner shoe. I

poles will have a low reluctance and the magnetic 'flux may readily pass between the pole pieces andthe pole shoes. 7

The poles are of-opposite polarity, and the flux created by the Winding passes from the frame and out through one pole, then across the space between the through the other pole.

poles and back The. attraction produced by thei flux is toward the polar faces and not the interveningspace between the poles. In conse- I ing from damage and the'plate from wear in engagement therewlith,;the entirej load be- 'ingjpenetrated itaattracted to the magn The pole 'shoes are rugged and strong so 5s "asto wahs the w Shocks and Warquence, when the material is attracted, it-is pulled toward the polar faces.

The poles project sufliciently below the winding and cover plate to protect the windwhen the, material is attracted, and only occasionally will 1 any material engage the cover plate.

If pig iron is being lifted some pigs will bridge the poles, being attracted at one end to the outer pole and at-the'other end to the inner pole, and others will simply hang down from the. poles and the pigs directly by the magnetic flux to keep occurring inservice, partlcularly in lifting rough material', such as pig ironandscrap.

e The'-outer ..pole extends sufiiciently below in the winding and cover plate to engage the-j the magnet islowered'or Z same, so as; to 'savethe'" material he s' 'an'st the j j I, windmg and-cover @P m blows" and fii'e e ia -ironic gagefiieiitwith the cover-plate. i

" wear} am am acts like a guard to ward placed upon the other,

and similarly the When the magnet is employed to lift rough material the inner pole doesnot project ordinarily as low as the outer pole but has its polar facereceded'so as to make the magnet face somewhat concave. This struc- .ture enables the outer' pole to come more readily in contact with the material and at-. tract the same thereto. Where the polar faces are in the same plane, the inner pole is liableto engagethe material first and thus keep the outer pole so far from engagement therewith as to lessen the material it will attract.

The energizingcoil or winding is located;

in the annular space'or channel between the inner pole and is surrounded by the outer. pole.

The windlng is composed of sections, one four sections being inner and outer poles. It surrounds the a shown. Each section of the winding comprises a strip of copper 30 wound flatwise in the form of a spiral and having a strip of asbestos or'other insulating material '31 wound therewith so as to insulate the turns from each other.

The sections are preferably wound upon a metallic tube'32, which is surrounded by a mica or other insulating covering 33. The tube 32 fits over the inner pole piece 12 of the magnet: The

ad acent sections of the winding are wound in different directionsso that the same will produce like polarity. For instance, the

first section is ,wound clockwise and the next section counter clockwise, and so on alternately in reverse direction. The outer ends 34 of the top and bottom sections form the terminals of the winding. Insulating disks 35 are placed above and below thew1nding and betweenits several sections. The inner ends of the top and bottom sections are connected to the-inner ends of the adjacent sections, and the outside ends of the two inter-' mediate sections are connected to each other.

The manner 'ofconnecting two sections of the winding is illustrated in Fig. VII, which 1s a perspective view looking at the inside of the top section and its adjacent intermediate section. The inner end of each section is folded to"extend at an angle and thus the inner ends of the two sectionsare over lapped, these overlapping ends being joined by a rivet orin any other suitable way.

The outer ends of the two intermediate secgles to extend upwardly and are. then bent- D Q the t p f he Wind ng nd attached to each section, the inner end of the coil is prefrun once around so 7 and bottomv sections arefolded at right anterminal bolts 36. Insulating pieces 37 arepreferably placed between the top disk 35 and the bent-over portions of the-ends 34.

.1 preferably place bands 38 around the outside of the winding the ends of which bands are drawn together by bolts 39 to firmly bind the bands around the winding. I preferably place one band around each of the top and bottom sections between the insulating disks and a single band around the two intermediate sections. These bands are insulated from the sections by some suitable material.

p or other suitable material which will readily conduct heat from the winding to the mag bear upon blocks of asbestos- The winding is firmly held in place by means of bolts 40' threaded through the outer pole piece and preferably equally spaced around .the Winding).0 These bolts ard 41, which bear upon the outside of the winding, these blocks being set in notches 42 in the insulat ing disk 35. A space is left between'the energizing winding and the outer pole in or- .der that the portions of the winding between the spacing blocks 41 may spread outwardly ,when the winding expands. The space between the winding and the walls of the annular recess may be filled with sand net frame from whichit will be dissipated.

V The top of the annular recess 14 is-provided with an indentation 43 to receive the bent-over portion of the terminal ends 34 of the winding. The terminal bolts extend upwardly through the magnet frame and are fastened to binding posts 44, which rest.upon an insulating block'45 of the magnet frame.

laced upon the top he bolts 36 are insulated from the frame by insulating tubes 46. These bolts are preferably attached to the binding posts 44 by means of nuts 47. The insulating block 45 is preferably attached to the magnet frame by means of bolts 48. Over the binding posts 44 extends a housing 49 which is secured to the to of the magnet frame by means of bolts 50. The top of the housing'is provided with water proof bushings 51, through which run the supply wires 52 from which power is taken to energize the Winding. These wires are connected to the binding posts 44.

The energizing winding composed of sections,,each comprising a flat strip in the form of a spiral coil, gives a greater numher of ampere turns. for a given voltage and a winding of a given diameter and cross sectional area thanv can be obtained under the same conditions with insulated circular wires. v

The inner polar face is of lessarea than the outer polar face so that the density of the magnetic flux-will be greater at the in ner pole than at the outer pole. Accordingly the inner pole is stronger than the outer pole. The inner polar face is receded orset of the hopper.

back of the plane in whichthe outer polar face is located, so that the-face of the magnet is what may be termed concave. These features make the magnet especially adapted to lift loose material from a pile, such as pig iron and other material of less length than the diameter of the magnet.

-Among the advantages and results which this magnet obtains over prior magnets, is that it has greater efficiency and a higher lifting capacity for a given weight and size. It has greater strength and will withstand more s ocks, blows, and strains. It

will give longer continuous service, and require less repair. Its wmdmg 1s thoroughly protected and is less liable to damage. v

I Fig. 8 shows the magnet lifting pig-iron. A number of pigs bridge the inner andouter poles and complete the magnetic circuit.

magnet. j The inner pole is strong enough to hold a number of pigs which hang down. It is found in practice that with the inner pole receded and of greater strength than be firmly held, and further by the fact that the inner pole willhold a number of pieces alone. In other words the load is concen trated toward the center. If the inner pole were not receded the chances are that it would directly engage the pile ofmaterial and prevent the outer pole from coming sufficiently close to' the material, to attract as many pieces. Moreover the outer pole would notbe sufficiently strong to draw. up the pieces attracted by the inner pole so that these pieces would bridge the two poles and be firmly held. Hence the fact that my magnet is especially adaptcdfor lifting pigiron and other loose material.

My magnet possesses another advantage in handling loose material, and this'advantage appears when the material is dropped from the magnet. Whenthe material is released from the magnet the pieces fall inwardly toward each other because the outer pole, which is-weaker than the inner pole,

will release the pieces first, and they will therefore swing inwardly. Accordingly if the .load is delivered to the ground it will be deposited in a compact pile, or if it is deliv- These pigs are thereby firmly held to the I and cause them to bridge the two poles and ered to a hopper it will not fly over the edges Where the magnet is'used' to lift steel gots, blooms, slabs or other material of greater length thanits diameter, it is preferable that the inner polar face and the outer polar face should be in the same plane, ,so i

that there will not be an air gap between the inner pole and the load.

In Fig. 9 I have diagrammatically illustrated the magnet lifting a slab. In order to eliminate the air gap between the inner pole shoe.

inner and outer poles of opposite polarity pole and the slab, I may place an adapter or explanation.

Having thus described my invention what I claim as new and desire to secure by Letters-Patent is: 1

1. A liftingmagnet having a frame, rigid inner and outer poles of opposite polarity depending from said frame, and a winding arranged Within the space between said poles, the outer pole projecting sufliciently below the winding to protect the same and take the shocks and strains to which the magnet is subjected.

2. A lifting magnet having a frame, rigid inner and .outer poles of oppositepolarity depending from said frame, a winding arranged within the space between said poles, and a cover plate for said winding, the outer pole projecting sufiiciently below the winding to protect the same and take the shocks and strains to which the magnet is subjected. 3. A lifting magnet having a frame,'rigid depending from said frame, a winding. ar-

ranged within the space between said poles,

'. and a cover plate for said winding, with the poles projecting sufliciently below the winding to protect the same and take the shocks and strains to which the magnet is subjected.

4. A lifting magnet having a pair of rigid magnetic polesfor engaging the material to be lifted, an energizing winding arranged between said les, and a non-magnetic cover for the winding, one of said .poles projecting sufficiently below the winding and cover to protect the same and take the shocks and strains to which the magnet is subjected.

-' 5; A lifting'magnet having a pair of rigid I magnetic poles of low reluctance for engaging the material tQbB lifted, an energizing winding located between said poles, and a non-magnetic cover plate for the windingv and supported by-the poles,one of said poles projectingsufiiclently belowthe cover plate .to guard the same and protect the winding and take theshocks and strains'to which the e [,to protect the. .p1ate and winding and take magnet is subjected.

sufficiently below the winding to protect the same and take the shocks and strains to which the magnet is subjected' 7. A lifting magnet having a frame, rigid magnetic poles of opposite polarity depending from said frame and having shoulders near their bottom ends, an energizing winding arranged between said poles, and a nonmagnetic cover plate resting upon the shoulders and covering the winding, the outer pole projecting sufficiently below the plate to protect the plate and winding, and take. the shocks and strains to .which the magnet' is subjected.- I

8. A lifting magnethavinga frame, rigid pole pieces of opposite polarity depending from said frame, a winding arranged within the space between said poles, and massive removable magnetic pole shoes projecting from said pole pieces, the outer pole shoe extending sufficiently below the winding to protect the sameand take the shocks and strains to which'the magnet is subjected.

9. A lifting magnet comprising a framehaving an inner pole surrounded by an outer pole with. an annular-recess between said poles, a flat spiral energizmg winding. arranged in sa1d recess, sa1d-winding being wound from a flat strip of conducting mate-' rial and carried by a spool adapted to sur-' round said inner pole and be readily removable therefrom, a non-magnetic platecovering said recess and removable pole shoes-of magnetic material covering the active faces of said poles, said shoes being adapted to support said nonmagnetic plate.

10. A lifting magnet comprising a cylin-.

drical frame having an annular recess in one of the end faces thereof, an energizing winding in said recess comprising a plural-.

ity of-fiat spiral coils wound from a flat strip of conducting material and arranged one above another on a supporting spool and connected together so that their efiectis cumulative, a non-magnetic plate covering said recess and removable, pole'shoe's of ma netic material covering the portions of sa1d face adjacent said recess, said. shoes being adapted to support said non-magnetic plate.

11. -A'lifting magnet having a frame, rigid pole pieces of opposite polarity depending from said frame, a winding arranged within the space between said poles, a non-' magnetic cover plate for said winding, and massive removable magnetic pole shoes projecting from said pole pieces and holding said cover plate in place, the outer'pole. shoe extending sufficiently below the cover plate the shocks and strains to which the magnet is subjected."

12. A lifting magnet having-a frame provided with an inner pole surrounded by anannular outer' pole, an energizing winding arranged in an annular recess between said 'j'ected.

poles, and a heavy removable magnetic pole shoe on the active face of the outer pole'to protect the winding and to take the shocks and strains to which the magnet is sub- 13. A lifting magnet having a frame provided with an inner pole surrounded by an annular outer pole; an energizing windin arranged in an annular recess between s'ai 4 poles, a non-magnetic plate covering said recess, and aheavy' removable magnetic pole shoe on the active face ofthe outer pole to protect the magnet against the shocks and strains to' which it is subjected.

14'. A lifting magnet having a frame provided with an inner pole surrounded by 'anannular outer pole, an'energizing winding arranged in an annular recess between said poles, a non-magnetic plate covering said a recess, and a heavy removable magnetic pole shoe on the active face of one of said poles to take the shocks and strains to which the aignet is subjected, said shoe projecting vided with an inner pole surrounded-by an outer pole, an energizing winding in a recess between said poles, and independently i-removable pole shoes of magnetic material on the bottom faces of both of said poles,

the under face of the shoe on the outer pole being lower than the under face of the shoe on the inner pole.

17. A lifting magnet having a frame provided with an inner pole surrounded by an outer pole, an. energizing winding in a re- ,cess between said poles, a non-magnetic plate covering said recess, andindependently re- I movable pole shoes of magnetic material on the. bottom faces of said poles, said shoes bein adapted to support said plate, the under face of the shoe on the outer pole being lower than the under face of the shoe on the inner pole.

than that of the outer pole facefwh'ereby ciently below the winding to protect the lifting magnet provided with a frame having an inner pole surrounded by ,a continuous outer pole, an energizing wind ing arranged in arecess between said'poles, the area-of'the inner pole face being less -whenthe magnet is deenergized thetouter pole releases 1ts load before the inner pole.

I 19: In a lifting magnet, in combination, a magnet frame having an inner and an outer. pole, an energizing winding arranged in an annular recess formed between said, poles, and a non-ma "etic ribbed plate arranged in the face 0 said magnet between said polesand covering. said recess to protect said-coil.

. 20. In a lifting magnet, in combination, a magnet frame having an inner and an outer pole, an energizing'coil arranged in an annular recess formed between said poles, re-

movable pole shoes fastened to said poles and a plate covering said recess and held in positionby said pole shoes, said plate being arranged to hold said pole shoes against lateral movement.

21. In a lifting magnet, in combination, a magnet frame having an inner and outer pole, an energizing coil arranged invan annular recess formed between said poles, a nonmagnetic plate arranged in the'face of said magnet between said poles andcovermg said recess to protect said coil, removable pole shoes arranged on said poles for supporting said plate, said plate having an angularly disposed annular-flange overlapping the inner faces of the outer pole and its pole shoe.

In 'a -lifting magnet, a magnet frame having an inner and outer pole, an energizing winding arranged in an annular recess formed between said poles, removable pole shoes covering theactive' faces of saidpoles,

the shoes on said poles being out'of alinement, and the active face of the outer ole shoe being inclined toward the active ace of the inner pole shoe.

23. A lifting magnet outer pole, an energizing coil arranged in an annular recess between said inner and outer pole, a, spacebe ng'left between said COII'aHd.

7 said outer pole, means passing through said pole shoes on the active faces of said poles arranged to hold said plate in position.

' 24. A lifting magnet having a frame provided with an inner and an outer pole, one of said poles being receded, pole shoes of magnetic material covering the active faces of said poles, and a supplemental pole ,shoe

arranged on the receded pole so as to locate the. polar faces in plane.

25. -A lifting magnet having a frame provided with an inner pole surrounded by an outer pole, the face of the'inner pole being receded, poleshoes of magnetic material covering the. active faces of said poles and a substantially the same 10! having a frame provided with an inner pole surrounded by an supplemental pole shoe on said inner pole for locating the inner polar facein substantially the same plane as the outer polar face.

' ceded, an energizing winding arranged in an annular recess formed between sa1d outer 26. -In a lifting magnet, in combination, a magnet frame provided with a central opening and having. an inner'and an outer pole, the face of said inner pole being reand innerpoles, a supplmental pole shoe placed upon said innerpole to locate the inner polar face in substantially the same plane as the outer pole face, a cross piece extending across the opening in saidmagnet frame, and 'a bolt connecting said cross plece said poles, the pole shoe on the outer pole .being deeper than the poleshoe on the central pole, such that its under face is lower than the under face of the pole shoe on the central pole.

29. A lifting magnet having a central pole,

an outer pole and removable pole shoes on the bottom faces of said poles, one of said .shoes projecting below and, being thicker i'than the other of said shoes.

30. A lifting magnet. provided with inner I and outer poles having an annular space between the same, an energizing winding comprising a plurality of coils of flat conducting strips wound flatwise, said coils arranged one above another in the annular space between said poles, an annular nonmagnetic plate arranged between said poles to support said winding and magnetic-. pele shoes detachably secured inclose magnetic contact with said poles, said shoessiipporting said plate at its inner outer peripheries.

31. A liftingrmagnet provided with a cir cular magnet ame having concentric inner and outer poles presentlng a concave active face, an energizlng winding comprising a plurality of fiat coils formedofflatconducb ing strips, said coils being placed one upon "another in the annular spacebetWeen said poles, a non-magnetic .plate arranged between-said poles for supportmg and rotecting said wmding and removable 1pc e shoes detachably secured to said poles; said plate being supported by said-pole shoesw j 32. A lifting magnet provided witha circular magnet frame havlngco'ncentric inner and outer poles presenting a concave actlve face, an energizing wlndmg compr smga plurality of flat coils formed-of fiat conducting strips, said coils being placed one upon another in the annular space between said poles, a non-magnetic plate arranged between said poles for supporting and protecting said winding and-removable pole shoes 'detachably secured tosaid poles, said plate being supported by said pole shoes, and engaging said frame and said shoes to resist lateral movement of the latter.

33. A liftin 'magnet having a magnet frame provided with inner and outer poles, the inner polar face being receded with respect to the outer polar face, coils in the in tor-polar space, said coils being spaced from the outer poles to permit expansion of said coils, means for securing said coils in said spaced relation, protecting plates filling the mter-polar space to protect said coils and.

removable inner and outer pole shoes attached to the respective poles. Y 34. A lifting magnet having a magnet frame provided with inner and outer poles, the inner polar face being receded with respect to the outer polar face, coils in the inter-polar space, said coils-being spaced from the outer poles to. permit expanslon of said .co1ls, means for securing sa1d coils-1n sa1d spaced relation, protecting plates filling the inter-polar space to protect said coils and removable inner and outer pole shoes attached to the respective poles, said outer pole shoe having its active face inclined toward'said inner pole shoe whereby a conoave' active face is provided for said magnet.

35. A lifting magnet having a frame provided with. an inner pole 'surrounded'by,

an outer pole, an energizing winding compr smg a 0011 wound of flat strlps arranged man annular recess between sa1d poles, a

a' gheiagay removable magnetic pole shoe on; the outer pole to support said plate and .to

.protect the magnet against the shocks and strains to which it is subjected.

36. A lifting magnet having a frame provid'ed with an inner pole surrounded-by an.

outer pole, an energizing windingin an an-- nular recess between said poles, a non-magnet1c retaming plate coveringsaid annular recess and supported by a shoulder on the ,inpn iiragnetic plate covering said recess, and.

outer pole, and, a removablemagnetic pole shoe on the inner pole supporting the inner edge of said plate- A liftingmagnet having a frame pro,- Vid "with an inner pole, an energizing windingsi rrounding said pole, 'said frame having an'roaiter pole surrounding said winding and projecting. sufliciently below the same to protect it, a non-magnetic plate supported by a'fihoulderon said outer pole, and

a removableginagnetic pole shoe on the inner pole for. supporting the inner edge of said plate. i

-A lifting magnet having a frame pro- 13,0

Corrections in Letters Patent No. 1,325,914

'also engaging the outer pole whereby the pole shoes are held against lateral movement.

39. A lifting magnet having a frame,

rigid pole pieces depending therefrom, a

wmding arranged within the space between}.

said pole pieces and formed of sections, each section comprising a spirally wound fiat I Signedandsealed'thia'i winding, removable magnetic pole shoes fastened directly upon said pole pieces so that the pole pieces and pole shoes form poles,

the cover plate being held in place by the pole shoes and the outer pole shoe proJecting sufiiciently below the plate and winding to protect the same and take the shocks and strains to which the magnet is subjected.

In witness whereof, I have hereunto sub-.

scribed my name in the presence of two witnesses.

LEWIS D. ROWELL.

Witnesses:

OSCAR A. KELLER, WALTER E. SABGENT.

lIg' hereby certified that in Letters Patent No; 1,325,914, granted December23, 1919, upon the application of Lewis D. Rowell, of Milwaukee, Wisconsin,for animprovernent in lifting-Magnets, errorsappear in the printed specification requiring correction as follows: Page 2 line. 11}, comme ncing the article "ThQf Strike out the-paragraph to and including the word winding, liilegll'? i 'jp age'd line l0,-cla.im 26, forthe word suppl'me'ntal read supplemental; and said Letters Patent'should be read these corrections therein that the I conform of thecase in. the Patent Otfice. v i i i ay'jof March QAa D lIY QZO. Q i.

M. H. coULsTouj 'amw-g mmim a; was

strip, a cover plate arranged below said

Images