US 2884698 A
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y 1959 w. wURscH MAGNETIC HOLDING DEVICE WALTER WURSCH Filed June 5, 1957 INVENTOR.
AGENT United States Patent MAGNETIC HOLDING DEVICE Walter Wiirsch, Frauenfeld, Switzerland, assignoroffiftypercent'to Emannel S. Klausner Inc., New York, NIY.
Application June 3, 1957, Serial No. 663,140 Claims priority, application Switzerland June 6, 19561 1"Claim. (Cl; 33-75) My present invention relates to a magnetic holding device, adaptedto maintain two pieces of iron or. steel in aodesired relative position.
An object of this invention is to provide a devicefor. securely holding in position, at a selected angle to. each. other, two. pieces of ferrous metal to be joined together by, welding,soldering orother temporary or permanent bonding processes.
Another object of this invention isto provide a. device-of this character havingmeansfor immediately and. P cisely indicating the angle enclosed by two workpieces held thereby.
In accordance with a feature of my invention I provide a holding device comprising a pair of pivotally inter-- connected, relatively swingable arms each bearing on. its free end, remote from their pivot, a magnetic retain-.-
ing head having a housing with a fiat work face whence emanate-the lines of force-of one or more magnets positioned withinthe. housing. The arms are provided with clamping means, such as a handle threadedly engaging a boltserving astheirpivot, for locking them in a selected relative angular position.
According to-another feature of my inventionthere are provided two relatively-movable indicator'members, such as a scale and a pointer, respectively supported bythe two arms so as to enable a'direct reading of their relative angular position. Advantageously, the indicator members are calibratedto give a zero reading in a position of coplanarity of the two work faces. The arms may further beprovided with co-operating abutment means-establishing a limiting position therefor, this limiting position being preferably displaced by an angle o f.90 from their position of coplanarity.
A further feature of my invention resides ina novel construction of each retaining head designed to furnish a maximum of magnetic flux paths adapted to be closed through a ferromagnetic member placed in contact with the gripper face. In accordance with this feature I position one or more magnets, preferably of the permanent type, in an annular zone spaced from the rim of the generally cup-shaped, ferromagnetic housing so that the pole face or faces thereof are flush with this rim, whereby a first annular air gap is formed between this zone and the rim; and I also insert into the housing a central ferromagnetic stud, spaced from the magnet or magnets, so that a second annular air gap is formed between this stud and the magnetic zone. The voids left between the rim, the stud and the magnet or magnets may be filled up, in whole or in part, with coplanar spacers of non-magnetic material which together with the former define the work face of the retaining head. The axes of the two work faces are preferably located in a common plane transverse to the pivotal axis of the swingable arms.
A device of this type may be employed not only in welding or otherwise joining two members together but also to facilitate the scribing of a ferrous body in a pre-.
determined angular position relative to a support, as well as for a variety of other uses.
The above-and other objects, features and advantages of my invention will become more fully apparent from the following detailed description, reference being had to. the -accompanying drawing in which:
Fig. 1 is an elevational view, partly in section, of a device embodying the. invention;
Fig. 2 is atop plan view, partly in section on the line II.--II ofFig. 1, of the samedevice;
Fig. 3 isv a bottom view ofv one of the grippers of the device, taken on the line III--HI of Fig. l; and
Figs. 4 and 5 are views similar to Fig. 3, showing two modifications.
The device shown in Figs. 1-3 comprises two arms 1 and 2, which are relatively swingable about a pivot constituted by a threaded bolt 14; Each of arms 1 and 2. has secured-to it, by; means of a screw 4, a magnetic retaining head 3. Arm 1 terminates, at its end opposite the one bearing its head3', in a disk-shaped coupling element 5 integral with that arm and provided with a conicalcentral boss 6; this boss has an axial bore 7 whose female threads 8 matingly engage the male threads on bolt 14. For its properpositioning inside the bore 7, bolt 14 is provided witha hexagonal socket13 adapted to receive a complementary wrench not shown.v It will be understood that. threaded bore 7, which is only in part occupied by the. bolt 14, may also receive. male fastening means, such as a screw 32 (as shown in dotdash lines), by which the device may be secured to an external support.
Arm 2.terminates, atits end opposite tothe one bearing, the other head 3', in a disk-shaped coupling element 9 integral withit and complementary to coupling mem-. her 5; Coupling element 9 is offrustoconical configuration and has an axial bore 10 which is unthreaded andlargeenough to be traversed by the bolt 14 with some clearance. The base of'the frustocone is stepped to form shoulders 11. and 12 received'in complementary recesses of coupling element 5. Thus, element 9 is positively maintained in a position of concentricity with element 5.
into a lockingposition.
Each'of theheads 3 comprises, agenerally cup-shaped housing 17 of soft iron in which is seatedan' annular permanent magnet 18*magnetized in an axial direction, its two poles having been indicated at N and S. The height of magnet 18 equals that of the cylindrical portion of housing 17 so that one of its poles (here the South pole S) lies flush with the rim of that housing. A soft-iron stud 19 is centrally positioned within housing 17 and magnet 18 and is held in position by the screw 4, its length equaling the axial length of the magnet. The voids formed between the magnet and its yoke 17, 19 are filled, at least in the region remote from the bottom of cup 17, by annular spacers 20 and 21 of non-magnetic material, e.g. brass, spacer 20 being interposed between boss 19 and magnet 18 while spacer 21 is inserted between the latter and housing 17. Thus, the aligned extremities of members 1721 constitute an unbroken surface 23 against which a work piece, such as a sheet 26 or 27 as indicated in dot-dash lines in Fig. 1, may come to rest. The work faces 23 of the two retaining heads are parallel to the axis of pivot 14 and equidistant therefrom.
The flux emanating from magnet 18 has been indicated by lines of force 22 which emerge from the work face 23 and, in the absence of a work piece, close through the annular air gaps existing across the spacer rings 20 and 21. This flux will thus almost entirely pass through the work piece when the latter is operatively positioned against the retaining head, thereby firmly keeping this work piece attracted.
A degree scale 24, provided'on' the conical face of coupling element 9, and a pointer 25, provided on a pcripheral zone of element 5 surrounding this scale, cooperate to indicate the relativeangular position of the work faces 23 of the two heads 3. In the position illustrated in Figs. 1 and 2, the pointer 25 is aligned with the zero mark of scale 24 to indicate that the two work'faces, and therefore the Work pieces 26 and 27 held by them, are in exact alignment with each other. It will be noted that the general direction of the arms 1 and 2 is inclined 1 relatively to their respective Work faces so that anangle other than zero is enclosed by these arms in the illustrated position of operative alignment. The arms are, furthermore, provided with abutments 28, 29 which, by their mutual engagement, define a limiting angular position in which the work faces 23 are exactly perpendicular to each other, the pointer 25 then indicating an angle of 90 on the scale 24. The total range of relative rotation of the two arms, indicated by the arrows 30, is ap proximately 270.
' For a more accurate determination of the angular position of the work faces, the pointer 25 may form part of a vernier scale 31 provided on coupling element 5.
pole faces of like polarity (here their North poles) flush with the rim of housing 217a. Rings 220a, 220k and 221a, 2211; of brass or other non-magnetic material serve as spacers between the magnets and the yoke, all the elements shown in Fig. 5 being level with one another to define again an unbroken work face.
Other modifications and adaptations of the principles herein disclosed will readily be apparent to persons skilled in the art and are intended to be embraced in the scope of my invention as defined in the appended claim. Thus, for example, it may be desirable (especially for larger devices) to use a larger number of magnetic zones and/ or to replace the permanent magnets by electromagnets.
I claim: a
A magnetic holding device comprising a generally cupshaped first coupling member, a generally disk-shaped second coupling member concentric with and rotatably received said first coupling member, a pair of arms 2 each provided with a vflat work face and extending from a respective one of said coupling members, said arms be-' ing swingable about the common axis of said coupling members and enclosing with each other an obtuse angle in a eo-planar position of said work' faces, said coupling It will he noted that the largest radius of the coupling elements, i.e. the outer radius of the annular zone of element 5 bearing the Vernier scale 31, is less than the distance of the plane of either face 23 from the pivotal axis of the arms 1 and 2 so that these elements will not interfere with the positioning of the Work pieces 26 and 27 which are to be welded together or otherwise operated upon in a selected relative position.
In Fig. 4 I have shown a modified retaining head 103 whose housing 117, stud '119 and annular spacers 120, 121 are similar to the elements 17, 19, 20 and 21 of the preceding embodiment but wherein the single annular magnet 18 has been replaced by a series of rod magnets 118. The operation of this retaining head is similar to that of head 3 in that a strong magnetomotive force is again developed across the major portion of its working surface.
A retaining head according to the invention may also be provided with more than one annular magnetic zone. In Fig. 5 the head 203 is provided, between the periphery of its housing 217a and its center stud 219, with a dividing ring 217b of soft iron which together with the elements 217a and 219 of like material constitutes a threelegged yoke. Concentrically positioned between the legs of this yoke are two annular magnets 218a, 218b having member having a conical face hearing some of said mark-" ings 3 References Cited in the file of this patent UNITED STATES PATENTS 678,005 Myers July 9, 1901 1,121,303 Smith Dec. 15, 1914 1,260,292 Anderson Mar. 26, 1918 2,108,077 Robinson Feb. 15, 1938 2,287,286 Bing et a1. June 23, 1942 2,390,865 Bemis Dec. 11, 1945 2,471,067 Hitchcock May 24, 1949 2,585,714 Wrobel Feb. 12, 1952. 2,615,738 Johnson Oct. 28, 1952 2,623,256 Fibelman Dec. 30, 1952. 2,803,208 Bernard Aug. 20, 1957 FOREIGN PATENTS members being provided on adjacent surfaces'vvith cooperating markings indicating the angle enclosed by said work faces in different relative angular positions of said arms, abutment means on said arms engaging each other in a limiting position in which said angle is said abutment means enabling a relative rotation of said arms through an angle of substantially 270, and locking means traversing said coupling members for releasably securing them in a selected angular position, said second coupling- Sweden Mar, 29,1955