US1507777A

US1507777A - Magnetic chuck

Info

Publication number: US1507777A
Application number: US288747A
Authority: US
Inventors: Karasick Samuel
Original assignee: Individual
Current assignee: Individual
Priority date: 1919-04-09
Filing date: 1919-04-09
Publication date: 1924-09-09
Anticipated expiration: 1941-09-09

Description

Sept: 9 1924.

s. KARASICK MAGNETIC CHUCK Filed April 9-. 1919 2 spun-sheet 1 Sept. 9', 1924. I

s". KARASICK MAGNETIC CHUCK Filed April 9.. 1919 2 Sheets-Shut 2 Patented Sept. 9, 1924.

UNITED STATES SAMUEL KARASICK, OF NEW YORK, N. Y.-

monnrro cnuox;

Application filed April 9,

i To all whom it may concern:

Be it known that I, SAMUEL KARASICK,

a citizen of the United States, residing at New York, State of New York, have invented a'new and useful Magnetic Chuck, of which the following is a specification. This invention relates to electromagnetic lifting and holding devices,.and more particularly to that class of devices which are known in the art as'magnetic chucks.

In devices of this character it has formerly been necessary to have a source of direct current to energize the same and in case only alternating current was available it was necessary to obtain a direct current generator in order to provide the necessary direct current.

The present invention has for its purpose the construction and arrangement of parts in a magnetic chuck, whereby the same may be energized by either direct or alternating current and whereby the work to be held is at all times firmly attracted to the device when actuated. This important result is obtained without readjustment of parts or without the heating of the'device.

It is also the purpose of this invention to provide a magnetic chuck which is simple to assemble, inexpensive to manufacture and which is reliable in operation. Other features not specifically mentioned will appear from the description and appended i il d I F i n t e rawin' i 1 represents a perspective view of a pr eferred formv of the invention. A portion of the chuck has been broken away in this view in order to partially show the arrangement of the parts; Fig. 2 shows a modified form of magnetic chuck also in perspective with a portion of the device broken away to show the construction and arrangement of parts; Figs. 3 and 4 show modifications wherein various parts of a chuck are provided with an arrangement for rendering certain portions of the device electrically sluggish 5 Fig. 5 shows a diagrammatic view of Fig. 3, and Fig. 6 is a diagram showin the relation between the flux and time w en the arrangements shown in Figs. 3, 4 and 5 are empkiyed.

eferrmg to Fig. l ofthe drawings, the.

. numeral 1 designates a-core. This core is built up of a pluralityof laminae, each of which Is made of a stamping from sheet metal having a body portion 2' provided frame; While thus arran .magnetic material, such as bb1tt1n 1919. Serial N0. 288,747.

with a series of integral uprights or co,

elements 3 and extensions terminatin in lugs 4. In casexthe chuck is designed to use alternating current, the laminae are first shellacked or enameled and then riveted together in any Well-known manner to form an integral structure. The core 1 when thus assembled is placed in a suitable mold or support and a base 5 of aluminum or other material having the properties and characteristics of this metal is molded about the core 1. The lugs 4 of the core are en aged by a lug 6 which is cast integral wit the base. When the base and assembled core have thus been made, each of the uprights or core elements is provided with a. spool 7 provided with awell-known coil or helix for its energization. It will be understood that these coils may be connected in any well-known manner in accordance with the character of the current to be supplied to the chuck. The chuck in this form is provided with a face plate on which the work to be held rests, and which prevents dust or moisture from entering into the core and coils of the device. Thisface plate is made up of a frame 8 and a series of polepieces 9-9, each polepiece being separated from the others and from the frame 8, as will be further described.- The polepieces 9, like the core, are also constructed of a series of laminae which may or may not beshellacked or enameled as in the case of the core, and

are held together by rivets 1O threaded through each of the laminae. It will be noted that the rivets compress the center portion of the laminae near the end of the polepieces so that the ends present a concave surface as shown in Fig. 1.. The lateral surface of the polepieces as well as the opposing inner surface of the frame, are provided with notches 11 which coo crate in the manner to be described. Iih assembling the face plate, the frame 8 is placed on a level surface and the polepieces 9-9 are also placed on this surface within the frame, care being taken to separate them from each other and from the surrounding ed suitable nonmetal, is poured in the spaces 12 between t e poleieces and between 'these pieces and the iiame. This metal when hardened engages the notches 11 of the frame and ole pieces and also engages the concave sur aces of the ends of the polepieces and the sides lateral surfaces of the polepieces are beveled so that their lower faces are substantially equal to the surface of the polepieces with which they engage, in order to lessen the leakage of flux between adjacent polepieces. On the side of the chuck there is mounted a switch box 13 in which is mounted a switch operating to make or break connection between the coils and the cable 14.

Referring to the modification of the invention shown in Fig. 2, there is provided a cast metal base 15 provided with threaded, raised portions 16 on its inner bottom surface. This form of magnetic chuck has a core element also made of a series of laminae riveted together of a form substantially the same as shown in Fig. 1, except 'that the lateral extensions andlugs l are not necessary in the present arrangement. In this case the core is fastened to the threaded, raised portions 16 by a brass screw 17. It will be noted that the core is also magnetically insulated from the base,

by brass washers 18. The uprights of the core are provided with spools 19 upon which are wound the energizing coils for the various elements of. the core. The open side of the base 15 is closed by a face plate 20. This face plate is substantially the same as the face plate of Fig. 1, except that the laminated polepieces have interlocking portions' The polepiece 21 is provided with laterally extending portions 23-2 3 which engage similar lateral extensions 24-24: of the polepiece 22. Theselateral extensions 23 and 24 of the polepieces 21 and 22 are each provided with an aligning opening 25 through which a rivet 26 is threaded to lock the adjacent polepieces in position; The polepieces thus assembled are.

placed on a level surface with the surrounding frame of the face plate properly positioned around them. Molten'non-mag netic material is then poured in the space between the polepieces and the frame, this non-magnetic material serving not only to I magnetically insulate each of the polepieces from each other and the frame, but also "serves to'lock the polepieces in the frame andgive strength and rigidity to the whole face plate.

When alternating current is employed to energize the chuck, the workto be held on the chuck may not-always be firmly-held on its surface unless it is provided with cer-' tain arrangements. In order to obviate this difficultyit is necessary to provide means which will maintain the flux in certain por- I tions of the core until the fluxhas been built up in other portions during each reversal of current. Several different modifications of means forthis pur so are shown. Flg. 3 a note '27 is cut longitudinally into the surface of the polepieces 9 and a band of copper isplaced in this notch and tions of each of the polepieces, as shown in Fig. 4.

These various flux-maintaining devices shown are merely typical and may he replaced by any arrangement in which certain portions of the chuck are rendered electrically sluggish.

The effect of these devices is best shown by reference to Fig. 6, which represents curves showing the relation between time and flux in the various portions of the cores of Figs. 3, 4 and 5. The flux in the portions of the core which are not provided with a copper jacket is illustrated by the curve A, whereas the flux through the'porti'ons of the core which are affected by the copper jacket is represented by the curve B. It will thus be seen that some portions of the polepieces are provided with magnetic flux, while the lines of force in the other portions of the polepieces have died down to zero.

It will be understood that the present invention, although shown in connection with I magnetic chucks, may be employed-in any relation where it is desired to lift, hold or carry magnetic articles. It will also be understood that where the copper jacket has been mentioned, any other metal may be the pole pieces, fixing the pole pieces with .a free surface of each in substantially the same plane, and placing said pole pieces ad- I jacent said core.

2. The method of forming electroma gnetic chucks which consists in assembling a core' of laminae, casting a base about said core, placing coils onv said core, assembling the pole pieces, fixing the pole pieces with a free surface of each in substantially the same plane, and placing saidpolefpieces adjacent said core."

3. The method of making electromagnetic chucks which consists of making a suitablecore element, casting a base about said element, placing coils on said core, assembling pole pieces of laminae, arranging the free parallel planes,-and placing said pole pieces I adjacent said core.

4. In an electroma etic chuck, a laminated unitary core e ement having a plusurfaces of said pole pieces in substantially 15 of extensions, a securing polepieces being in engagement with said projections but separated from said frame by non-magnetic material.

5. In an electromagnetic chuck, a laminated core element having three or more extensions, coils thereon, an inclosing structure formed of non-magnetic material cast integral with said core, pole pieces separated from each other but held in fixed relation by non-magnetic material cast inte ral therewith, said pole pieces being place adjacent said core.

6. In an electromagnetic chuck, an element formed of laminae having a plurality element for clamping the laminae together, a base of nonmagnetic material cast about and engaging the ends of said core, coils for said core, pole pieces extending at right angles to the plane of said laminae, said pole pieces being placed adjacent said core.

7. In an electromagnetic chuck, a core having three or more integral parallel extensions and free ends, a base of non-ma netic material and cast about'the free en 5 of said core, coils for said core, and a laminated pole piece engaging said extensions.

In witness whereof, I hereunto subscribe my name this 7 day of April, A. D. 1919.

SAMUEL KARASIGK.