US2186074A

US2186074A - Magnetic work holder

Info

Publication number: US2186074A
Application number: US273553A
Authority: US
Inventors: Koller Steven
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-05-13
Filing date: 1939-05-13
Publication date: 1940-01-09
Anticipated expiration: 1957-01-09

Description

Jan. 9, 1940. s. KOLLER MAGNETIC WORK HOLDER Filed May 13, 1959 2 Sheets-Sheet 1 Sieren Kalle? W QWN S. KOLLER MAGNETIC WORK HOLDER Filed May 13, 1939 2 Sheets-Sheet 2 gwuc/wboas (q Sieve}: K lie? Patented Jan. 9, 1 940 UNITED STATES PATENT OFFICE "Steven Koller, Detroit, Mich.

- Application May 13, 1939, Serial No. 273,553

Claims.

This invention relates to improvements in work holding devices and pertains particularly to an improved magnetic chuck.

The present invention has .for its primary object .to provide an improved permanent magnet chuck by means of which articles of magnetic material which are to be worked upomfor example,to beground, are held in a desired working position by magnetic force, the device including means whereby the piece of work may be released through the shifting of the permanent magnets to a non-working position.

Another object of the invention is to provide in a permanent magnet chuck of the character specified, novel means for divertingthe flow of magnetic flux between the poles of the permanent magnets forming a part of the device whereby the flux wil become effective to hold a magnetic body in position on the chuck, orv for shunting the-magnetic fiux from the body of magnetic material so that it will flow directly between the poles of the permanent magnets and thereby release the magnetic body from holding position.

Ihe invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not to be confined to any strict conformity with the showing of the drawings butmay be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

Fig. 3 is a sectional view taken substantially on the line 3--3 of Fig. ,2. v

-Fig. 4 isa fragmentary view illustrating the position to which a magnet unit may be oscillated from the position in which the units are shown in Fig. 2. g

Fig. 5 is a sectional view on the line 5-5 of Fig. v2, showing the magnet unit in off or nonholding position with respect to a body of work 7 which may be placed upon the top of the chuck.

Fig. 6 is a sectional View corresponding to Fig. 5, but showing the magnetic unit turned to on or work holding position.

Referring now more particularly to the drawings, the numeral I generally designates the bottom or base plate of the present permanent magnet chuck, which plate may be secured in any desired manner to a suitable supporting base. 5

Disposedover and resting upon the base I is a box unit 2 which has the upstanding side and

end walls

3 and 4, respectively, and the integral top wall '5- in which is formed anopening- 6 which extends longitudinally of the top wall and 10 through the ends thereof, the sides of this opening 6 being downwardly divergent so that the opening in cross-section is of dove-tail form.

Designed to be fitted into the opening 6 is a unit indicated generally by the numeral 1 and -made up of longitudinally extending strips of soft iron 8 and non-magnetic material 9, such as brass or the like arranged alternately as shown in Figs. 5 and 6. These strips which make up the unit 'I are secured together by the transversely extending pins ll) of brass or other non-magnetic material and this unit, which in effect constitutes the work supporting head or work holding head, is positioned in the opening 6 by being inserted-longitudinally from one end across the top edge of an end wall 4, as illustrated in Fig. 3.

After the head unit I is located in position, it is secured against longitudinal movement by the attachment of end cover plates H which are secured by screws l2 or in any other suitable manner to the end walls 4.

The box 2 is secured to the base plate I by suitable vertical securing pins or bolts l3 which, as shown in Figs. 2 and 3, pass upwardly through the base into the walls of the box. I

Within the chamber C which is formed by the box or casing 2; there is arranged a series or group of permanent magnet units, each of which units is indicated by the numeral 14. Each of these units is' made up of a plurality of horseshoe mag- 40 nets 15 which are secured together in side by side relation, as shown by bolts I6 of non-magnetic material which pass through the magnets between the legs thereof. These bolts also pass through the vertically arranged side plate ll of an angle bracket of' non-magnetic material, the other plate of which is indicated by the numeral l8 and is horizontally arranged, passing beneath the magnets l5, as shown in Fig. 5.

The bottom plate l8 of each magnet unit supporting bracket has secured to it a pivot pin or stud J9, which extends ,downwardly through a bearing unit 20 which'is disposed in a suitable opening 2| within the base plate I, the stud I9 beingheld against removal from the bearing s5 unit by a screw and washer assembly 22, as'

shown in Figs. 5 and 6. By this arrangement each magnet unit is supported for oscillation on a vertical axis. The ends of the legs of the magnets are directed upwardly and are disposed in close proximity to the underside of the workholding head unit I.

The numeral 23 designates an actuating plate by means of which the simultaneous oscillation of the magnet units I4 is effected. This plate is disposed upon the top of the base I for sliding or shifting movement transversely thereof, beneath the plates l8 of the magnet unit supporting brackets and it is provided with the series or group of longitudinally extending slots 24, each of which receives a coupling pin 25 which is carried by the adjacent bracket plate l8 and which extends downwardly therefrom adjacent a corner of the magnet unit. As shown in Fig. 2, the coupling pin receiving slots are so arranged that when the plate 23 is in one position or is adjacent one side of the chamber C, all of the magnet units within the chamber will be arranged so that the path of magnetic flux between the poles of the magnets of each unit will flow longitudinally of the work holding unit 1, thereby following the soft iron strips 8 of this unit. When the plate 23 is shifted across the chamber C, it will effect the oscillation of the magnet units through a quarter turn so as to bring each of these units into the position illustrated in Fig. 4, and also in Fig. 6, which position is at right angles to the position of these units as they are shown in Figs. 2 and 3. When in this position, it will be apparent that the path of magnetic flux cannot flow between the poles of the magnets of the units because such path will be at right angles to the length of the soft iron strips 8 which have interosed between them the non-magnetic material 9.

The oscillation of the plate 23 is effected by the provision of a boss 25' on the top of the plate at substantially its transversecenter, to which is attached one end of a shift 26 which passes through a suitable collar 21 mounted in the adjacent wall of the box 2, the rod terminating in the knob 28.

It is believed that it will be readily apparent from the foregoing that when a body of work W, consisting of a magnetic material, is placed upon the work receiving head and the magnet units are arranged as shown in Fig. 6, so that the path of magnetic flux betweenv the legs of the magnets through the soft iron strips 8 is interrupted, this path will be extended upwardly as indicated by the arrows in Fig. 6 to include the magnetic. body W, and in this manner the body will be firmly retained upon the work holding head. When the body W is to be released, the magnet actuating plate 23 is shifted horizontally across the chamber C soas to turn the magnet units to the position in which they are shown in Figs. 2, 3 and 5. The path of magnetic flux between the poles of the magnets will then'pass into and longitudinally through the soft iron strips 8 so that it will be deliverted away from or shunted from the magnetic body W and the body will be released for removal.

In the construction of the magnetic chuck described, it is preferred that use be made of the horseshoe type of permanent magnet as magnets of this character are made which are capable of lifting approximately forty times their own weight whereas the use of the old-fashioned straight magnets is undesirable because they have the ability only of lifting approximately four times their own weight.

By the grouping of such horseshoe magnets in the manner shown and by the arrangement of such groups or units in a series, as illustrated, it will be readily apparent that a particularly powerful holding action may be obtained upon a body of magnetic material placed upon' the disposed beneath said head with the ends of the side portions thereof directed toward the head. and supporting means facilitating the oscilla tion of said magnet on an axis perpendicular to the head whereby said magnet may be turned to either of two positions with respect to the head to cause the magnetic flux between the poles of the magnet to pass longitudinally through said magnetic strips or to divert said flow upwardly through the magnetic strips and between the non-magnetic strips to pass through the magnetic body upon the head.

2. A magnetic work holder, comprising a chambered body having a top plate provided with an opening, a magnetic material supporting head secured in said opening and consisting of a series of alternately arranged parallel strips of magnetic and non-magnetic material, a plurality of magnetic units within the chamber eachunit consisting of a group of horseshoe magnets\secured in side by side relation and having their poles directed toward the underside of said head and in close proximity thereto, a supporting bracket for each group of magnets, and means operable from outside said chamber for turning said supporting brackets and the group of magnets carried thereby through a substantially 90 path whereby said magnet groups may be shifted from a position where all are arranged to permit the path of magnetic flux between their poles to extend longitudinally along the said magnetic strips or to a position where said path will be at right angles to said strips.

3. A magnetic work holder, comprising a body forming a base, a second body forming a casing supported upon the base, the casing including a horizontal top wall having an opemng therein, a work supporting head secured in said opening and consisting of alternately arrangedstrips of magnetic and non-magnetic material. a plurality of magnet units disposed within the casing beneath said head and each consisting of a group of horseshoe magnets arranged in side by side relation with their poles directed toward, the underside of the head and in close'proximity thereto, a bracket supporting each group of magnets, a pivot pin carried by each bracket and extending downwardly into said base whereby each group of magnets may be oscillated on an axis extending perpendicular to the head, and means common t simultaneous oscilla ion of the same through a 90 arc whereby said units may be arranged to cause the paths of magnetic'flux between the poles of the magnets to extend longitudinally of the strips or to extend transversely thereof.

4. A magnetic work holder, comprising a head unit designed to support a body of work of magsaid brackets for efiecting flux longitudinally netic materialand having inner and outer plane s between the magnetic strips and through the magnetic piece of work and when in another position relative to the head unit releasing the piece of work through passage-of the magnetic of the magnetic strips from one pole to the other pole, and means for oscillating one unit relative to the other on an axis perpendicular to the work supporting plane surface of the head unit.

5. A magnetic work holder, comprising a work supporting head having inner and outer plane surfaces, said head consisting of alternately arranged strips of magnetic and non-magnetic material, a permanent magnet supported beneath said head for turning on a vertical axis, said magnet having poles disposed in a plane spaced from but adjacent to the inner plane surface of the head, and means for turning said magnet to either of two positions, in one of whichvpositions the magnetic flux path between the poles will pass vertically through and transversely between said magnetic strips through work on the head to hold the work thereon and in the other position the flux will pass longitudinally of the v magnetic strips to shunt the flux out of the work to release it from the head. STEVEN KOLLER.