US2481920A - Magnetic governor - Google Patents

Description

Sept. 13, 1949. Q z 2,481,920

MAGNETIC GOVERNOR Original Filed Aug. 15, 1941 r VIII/1151A." ill, I

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Patented Sept. 13, 1949 MAGNETIC GOVERNOR Charles LfFitz, Albany, Calif., assignor clone? half to Fred Dobbs and one-half to Charles Fitz, copartners, Three Lakes, Wis.

Original application August 15, 1941, Serial No. 406,942. Divided and this application July 12, 1945, Serial No. 604,626

invention relates to a magnetic governor. The present application is a division of my application Ser. No. 406,942, filed August 15, 1941, and issued October 2, 1945, for a Camera, as Patent No. 2,385,804, in which patent the governor is shown as a means of regulating the rate of movement of a camera shutter.

It is a primary object of the invention to provide a novel and improved governor preferably using a permanent magnet and adjustable as to the governing effect of such magnet with reference to a rotatable or oscillatable armature. My purposes will appear more fully in connection with the following disclosure of the invention.

In the drawings:

Fig. 1 is a plan view of apparatus embodying the invention.

Fig. 2 is a side elevation of the apparatus shown in Fig. 1, a cover plate and portions of a supporting frame being shown in section.

Fig. 3 is a detail view fragmentarily illustrating in plan a portion of the apparatus shown in Fig. 1.

While the mechanism governed in the accompanying disclosure of the invention happens to be a portion of the shutter operating-mechanism shown in the parent application above identified, it will, of course, be understood that the invention is of more general application. Merely by way of exemplification, the mechanism governed may comprise a gear 4 driven by a spring motor comprising the shell 5 and the torsion spring 6, the spring being connected, for winding, to the gear I.

The gear 4 driven by the spring motor is re,- ulated as to its rate of rotation by arotor which as shown, comprises a pinion 8 meshing with the gear and an armature which may constitute asegment 9, as shown in Figs. 1 and 2 or a complete annulus ID, as shown in Fig. 3. The rotors made up of disks or armatures 9 or- I0 and gear 9 preferably comprise ferrous or othermagnetic material and are mounted to turn unitarily on the headed stud II. Each of the armatures 9, I0 alternatively usable upon the gear 8 is provided with polar extensions I2 which preferably project axially as shown. The only difference between thearmature 9 and the armature I0 consists in the fact that armature I0 is provided with a complete annular series of the polar extensions I2, whereas armature 9 has the polar extensions about only a portion of its periphery. In the case of the armature 9, the magnetic governing action the armature only for the 'arcuate extent of its 11 Claims. (Cl. 188-404) seriesof polar extensions, whereas, in the case of the armature III, the arcuate extent of the series of polar extensions comprises a complete circle so that the magnetic governing action will be efiective continuously throughout armature rotation.

The frame member I3 is preferably likewise offerrous or other magnetic material, as are the .post I4 mounted thereon and the spring I5 supported by such post. The spring provides upward bias, as well as a fulcrum, for the bar magnet I6, the end of which is provided with a plurality of poles (preferably three in number) I'I,' I8. 19 which are formed concentric with the axis upon which the rotor 8, 9 revolves. Thus the polar extensions I2 of the armature rotate in immediate proximity to the poles I1, I8, I9 of the bar magnet I6. Additional upward bias for the bar magnet may be provided if desired by a supplementary spring 20 which preferably acts on the bar magnet substantially at its center. Opposed to spring 20 in its operation on the bar magnet is the adjusting screw. 2I threaded into a suitable boss in the cover plate 22 and adjustable against the bias of magnet It to force the magnet from the fully retracted position in which it is illustrated in full lines in Fig. 2 to the fully advanced horizontal position inwhich it is illustrated in broken lines ,in Fig. 2. In the horizontal position of the magnet, it develops its maximum braking effect'on the armature 9. In the course of armature rotation,'the

several poles I2 of the armature are rotated past with the poles I'I, I8, I9. Consequently, a retarding or braking eifect is exerted which tends to slow the rotation of the armature and'this effect may be regulated by means of the screw 2| and the opposing bias of the magnet whereby the magnet may be adjusted for any desired range of pivotal movement respecting the plane in which the armature rotates.

An additional braking action may be secured by using flexible brake shoes 23 of magnetizable materialacting between the frame member I3 and the rotor which comprises gear 8 and armature 8,

As shown, these shoes are riveted to the frame member l3 and have bearing portions in light friction contact with the under surface of gear 8. The particular arrangement is purely by way of exemplification. When the magnet I6 is in close proximity to the. rotor, some of its magnetism is communicated through the rotor to attract the magnetizable, flexible shoes 23 and thereby to increase their frictional bearing pressure on the rotor and, consequently, their drag or braking effect. Where the frame member l3, the support [4 and the spring l5 are all made of magnetizable material, a substantially closed magnetic circuit is established whereby the attraction between the shoes 23 and the parts frictionally engaged thereby is enhanced. The frictional braking pressure of the shoes 23, like the purely magnetic resistance developed in the armatures 9 or [0, depends for its intensity upon the position of the magnet 16. It will be relatively slight when the magnet is in the elevated position in which it is shown in full lines, and will be relatively strong when the magnet is in the horizontal position in which it is shown in broken lines.

While the members 9 or ID, with pinion 8, have been described as a rotor for the purposes of the present disclosure, it will be apparent that any one of these members may constitute the rotor in lieu of this composite rotor as illustrated. It will also be possible that a variety of changes are "portions in proximity to said rotor member whereby said magnet and its said connection and said support member and shoe and rotor member constitute a magnetic circuit substantially closed i save for the gap between the polar portions of the contemplated to be made within the scope of this disclosure and the appended claims.

I'claim:

l. A rotor comprising a rotatably mounted armature having polar extensions in arcuate series, in combination with a bar magnet having terminal polar projections complementary to those of the armature, and means supporting the bar magnet for relative adjustment of its polar projections to and from the plane of rotation of said armature and to and from proximity to the polar extensions of said armature.

2. In a governor, the combination with a rotor having polar projections in arcuate series, of a resiliently supported non-rotatable magnet having terminal polar projections complementary to those of the rotor and arranged for magnetic interaction therewith to develop a resistance to rotor rotation, means for yieldingly supporting the magnet for movement of its polar projections toward and away from the rotor, said magnet being biased for normal movement of its poles away from the rotor, and means for adjusting said magnet in opposition to its said bias, whereby to predetermine the normal spacing between its poles and those of the rotor to vary its initial responsiveness in the magnetic field of the rotor.

3. In a magnetic governor, the combination with a rotor and a magnet mounted for relative movement to and from each other, of a support in proximity to the rotor, and a magnetically remagnetically responsive material, and a magnet provided with an adjustable support on which said magnet is movable to and from said last mentioned member whereby to communicate to magnet and said rotor member, said magnet being adjustable upon its said connections whereby to vary said gap.

6. The combination with a magnet, a rotor member and a support member, of a shoe flexibly mounted on one of said members and in frictional engagement with the other and comprising magnetically responsive material, and means supporting said magnet for adjustment respecting at least one of said members said means and magnet and members and shoe comprising a magnetic circuit in which the adjustment of the magnet affords a variable gap for regulating the pressure contact of the shoe on the member frictionally engaged thereby. 1

'7. The combination with a support, of a rotor provided with axial polar projections in arcuate marginal series, at least one flexible brake shoe mounted on the support and flexibly engaging the rotor, a bar magnet having longitudinally projecting polar portions complementary to the axial polar extensions of the rotor, means mounting the end of the magnet remote from said polar portions for pivotal movement respecting the support whereby said magnet polar portions are movable to and from the plane of rotor rotation, and means for regulating the angular positioning of the magnet, said magnet and its mounting and the said support and rotor and shoe comprising magnetically responsive material in a circuit-substantially closed save as determined by the angular position of the magnet and the consequent gap between its polar portions and polar extensions of the rotor.

8. In a governor, the combination with a magnet member and an armature member mounted for relative rotation and having mutually complementary poles, the poles of one of said members being in arcuate series, said last mentioned member being rotatable and the arcuate extent of the poles of said series being less than 360 degrees, together with a supporting member adjacent the rotatable member, a brake shoe operative between the rotatable member and the supporting member and connected to one thereof, said brake shoe being of magnetizable material whereby its braking efiect will vary according to the continuity of the arcuate series of polar extensions on the rotatable member and the proximity of such polar extensions to the polar extensions on the first mentioned member.

9. In a governor, the combination with a magnetizable frame member, of a rotatable armature mounted thereon and having polar projections in arcuate series, a spring motor having gear con-- 'nection with said armature, a non-rotatable-magnetic brake resiliently mounted on said frame member and having terminal polar projections sv complementary to those of the armature, resilient means for normally retracting said brake to reduce the intensityof the magnetic field between it and the armature, and adjustable means for variably limiting the degree of brake retraction, whereby said brake is given a predeterminable range of movement in correspondence with the varying intensity of the magnetic field due to variations in the speed of the armature.

10. The combination with a magnetic rotor provided with poles and with a rotative mounting, of a non-rotative magnetic brake member provided with a support remote from said rotor and having a pivotal connection with said support, said member being provided with a free end portion adjacent the rotor having poles complementary to those of the rotor and movable about said pivotal connection to and from the plane of rotation of the rotor, together with means comprising an adjusting screw bearing on said member for adjustably determining the position of said member respecting said rotor, whereby to vary the magnetic braking interaction between the poles of said member and those of said rotor.

11. The combination with a magnetic rotor provided with poles and with a mounting for rotation, of a support remote therefrom, a flexible spring mounted on the support, a magnetic brake member carried by the spring and supported thereby from said support, said member being provided at its free end with poles complementary to those of the rotor and disposed in proximity thereto and relatively removable upon said spring pivotally to and from the plane of rotation of the rotor poles, and means comprising an opposing spring and screw bearing on said member for adjustably determining the relative positions of the poles of said member respecting those of said rotor.

CHARLES L. FITZ.

REFERENCES CITED The following references are of record in the file of this patent: 20

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