US3477049A

US3477049A - Electromagnetic actuating apparatus with the armature and pole pieces having corresponding surfaces in continuous rolling contact

Info

Publication number: US3477049A
Application number: US646287A
Authority: US
Inventors: Alfred Kreidler
Original assignee: Metall Invent SA
Current assignee: Metall Invent SA
Priority date: 1966-06-17
Filing date: 1967-06-15
Publication date: 1969-11-04
Anticipated expiration: 1986-11-04
Also published as: CH1031267A4; CH445605A; FR1563645A; CH517335A; DE1564338B2; DE1564338A1; DE6609865U; GB1189004A

Description

Nov. 4. 1969 A. KREIDLER 3,477,049

ELECTROMAGNETIC ACTUATING APPARATUS WITH THE ARMATURE AND POLE PIECES HAVING CORRESPONDING SURFACES IN CONTINUOUS ROLLING CONTACT Filed June 15, 1967 6 Sheets-Sheet 1 FIG. 7

FIG?

Nov. 4, 1969 A. KREIDLER 3,477,049

I ELECTROMAGNETIC ACTUATING APPARATUS WITH THE ARMATURE AND POLE PIECES HAVING CORRESPONDING SURFACES IN CONTINUOUS ROLLING CONTACT Filed. June 15, 1967 6 Sheets-Sheet 2 fivvzvrae '44 A 50 (Q5/045 Nov. 4, 1969 A. KREIDLER 3,477,049

ELECTROMAGNETIC ACTUATING APPARATUS WITH THE ARMATURE AND POLE PIECES HAVING CORRESPONDING SURFACES IN CONTINUOUS ROLLING CONTACT Filed June 15, 1967 V 6 Sheets-Sheet 3 v FIG. 4

fivyzvroe. 14/ 50 fizmzz/g Nov. 4, 1969' A. KREIDLER 3,477,049

ELECTROMAGNETIC ACTUAT ING APPARATUS WITH THE ARMATURE AND POLE PIECES HAVING" CORRESPONDING SURFACES IN CONTINUOUS ROLLING CONTACT Filed June 15, 1967 I 6 Sheets-Sheet 4 FIG. 7

Ax Va/rae 40- 50 flea/p4 a Nov. 4, 1969 A. KREIDLER 3,477,049

ELECTROMAGNETIC ACTUATING APPARATUS WITH THE ARMATURE AND POLE PIECES HAVING CORRESPONDING SURFACES IN CONTINUOUS ROLLING CONTACT Filed June 3.5, 1967 6 Sheets-Sheet 5 hazy/we. firgzo (fez/[145g NOV. 4, 1969 KRElDLER 3,477,049

ELECTROMAGNETIC ACTUATINC APPARATUS WITH THE ARMATURE AND POLE PIECES HAVING CORRESPONDING SURFACES IN CONTINUOUS ROLLING CONTACT Filed June 15, 1967 6 Sheets-Sheet 6 FIG. 73

1": 1717172 3 1: 115 17"" ULFUULI'JUULIUUUU FIG. 75a

United States Patent US. Cl. 335-276 8 Claims ABSTRACT OF THE DISCLOSURE An electromagnetic actuating apparatus in which an armature is attracted by an electromagnet when current is switched on. This kind of apparatus is employed for actuating electric switches, such as clockwork winders or the like. The armature rolls upon the pole piece in continuous rolling contact so as to reduce noise of operation.

This invention relates to an electromagnet actuating apparatus in which an armature is attracted by an electromagnet when current is switched on. This kind of apparatus is employed for actuating electric switches, such as clockwork winders or the like.

Striking of the armature upon the pole piece of an electromagnet results in a brief impact noise which is undesirable in many cases. Various measures are known whose purpose is to eliminate or at least to reduce the aforementioned impact noise. It has been proposed to dispose an intermediate layer of damping material, such as foam rubber, between the armature and the pole piece. Quite apart from the fact that such measures can only reduce but not completely eliminate the noise, such damping suifers from the disadvantage of substantially weakening the force effect of the magnet because, owing to the presence of the damping material, a gap of considerable size remains between the armature and pole piece. It is also known to swing the armature past the pole piece of the electromagnet perpendicularly to its axis. Although this procedure is completely free of noise, it necessitates an air gap of considerable size between armature and pole piece which in turn results in a considerable deterioration of the force effect.

The invention provides a remedy and enables the deliberate striking noise to be entirely avoided without incurring any new disadvantages. The solution to the problem is obtained in an electromagnetic actuating apparatus of the kind heretofore described by constructing the armature as a member which rolls upon the pole piece of the electromagnet. It is appropriate for the armature and pole piece to be in physical contact in the quiescent condition at the starting position of the rolling motion.

Two different basic armature forms are possible: the armature may be constructed as rigid member whose shape and method of guiding permits rolling upon a pole piece. Alternatively, the armature may be constructed as a resilient strip adapted for progressive bearing upon the pole piece.

Based upon the foregoing, it is possible to devise a plurality of embodiments of the invention which attain the still further objects and features which will become apparent as the following description proceeds, the embodiments being shown by way of example only, wherein.

3,477,049 Patented Nov. 4, 1969 FIG. 1 is a sectional detail view of the device provided with a solenoid core having a planar end face and a curved armature and provided with a tension spring;

FIG. 2. is a view similar to FIG. 1 of an embodiment employing a non-magnetic spring;

FIG. 3 is a sectional detail view of an embodiment of the invention employing a solenoid core having a convex end face and a straight armature;

FIG. 3a is a schematic illustration of an embodiment of the invention employing a solenoid core with a convex end face, a straight armature, and a clock winder mechamsrn;

FIG. 4 is a sectional detail view of an embodiment provided with a convex end face for the solenoid core and an arcuate armature;

FIG. 5 is a sectional detail view of a further embodiment provided with a linkage mechanism;

FIG. 6 is a sectional detail view illustrating an arrangement of an arcuate spring disposed between the solenoid core and the armature;

FIG. 7 is an illustration showing parts in section of an arrangement wherein the solenoid core and the armature are provided with complementary interengaging teeth;

FIGS. 7 and 8a are schematic diagrams of an arrangement employing an arcuate pole piece having portions of differing curvatures;

FIG. 9 is a sectional detail view illustrating an embodiment of the invention including a solenoid core provided with a convex face and employing a resilient straight armature;

FIG. 10 is a schematic illustration of an arrangement similar to FIG. 9 employing a resilient curved armature;

FIG. 11 is a schematic illustration of an arrangement wherein the solenoid core is planar and a resilient armature is curved;

FIG. 12 is a sectional detail view illustrating a modification of the invention employing a resilient strip armature mounted in a pivoted cradle;

FIG. 13 is a sectional detail view of an embodiment of the invention having a strip armature of non-magnetic material provided with soft iron pieces thereon;

FIG. 14 is a partial enlarged plan view of the strip armature shown in FIG. 3.

FIG. 14a is a partial plan view of a modified form of a strip armature;

FIG. 15 is a partial plan view of a modified form of a strip armature having soft iron members disposed between two non-magnetic strips; and

FIG. 15a is a longitudinal sectional view of the strip armature shown in FIG. 15.

With continuing reference to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, reference numeral 1 designates the solenoid core of a cup magnet utilized in the various embodiments of the invention. The solenoid core is disposed centrally in a cup structure 2 and is joined to its base. The cup 2 and core 1 are constructed of magnetizable material, mainly soft iron. A winding 3 in the cup 2 surrounds the solenoid core 1.

As shown in FIG. 1, the pole piece 4 formed by the end face of the cup 2 together with the end face of the solenoid core 1 is constructed in planar form. The armature 5 on the other hand is curved. It is retained in its initial or starting position by a tension spring 6 while touching the pole piece 4 at a tangential position 7 and bearing on its other side upon a stop 8. A further stop 9 limits the rolling motion resulting from the magnet action in the attracted position of the armature 5. A pivoting eye for the mechanism to be actuated is provided at that end of the armature 5 which faces away from the operating position of the tension spring 6.

FIG. 2 illustrates an arrangement similar to FIG. 1 wherein the tension spring and the stop are replaced by a shaped spring 11 of non-magnetic material. The non-magnetic material may be, for example, bronze.

The spring 11 at the same time serves for guiding and resetting of the armature 5 and is secured directly to the cup 2.

The example illustrated in FIG. 3 diifers from that illustrated in FIG. 1 only in that a plane or straight armature 12 cooperates with a pole piece 13, of the solenoid core 2, having a convex curvature.

FIG. 3a illustrates schematically an embodiment of the device shown in FIG. 3 with the principal parts of a clockwork associated therewith. A contact roll 54 is located at the free end of the armature 12. The contact roll 54 cooperates with the tensioning lever 55 which swivels about a shaft 56 of the ratchet gear 57. Tensioning lever 55 carries at one end thereof a flywheel mass 58 and at its other end a pawl 59 which is provided with a leaf spring 66 and engages the teeth 61 of the ratchet gear 57. A rigidly mounted stop 62 limits the swinging movement of tensioning lever 55 which is engaged by clock spring 63. The clock spring is shown diagrammatically as a helical tensioning spring for the sake of simplicity. The clockwork proper is indicated schematically by

circles

64 and 65. A battery 66 is connected with the coil 3 of the magnet through the conductor lead 67. Armature 12 is electrically connected through lead 68 and tensioning spring 6 and through contact roll 54 conductively engaging tensioning lever 55 in the position shown. The circuit to the battery 66 is closed over the clock spring 63 and conductor lead 69.

At the location shown, the electromagnet coil 3 is supplied with current, the armature 12 is wound and the tensioning lever 55 swivels over roll 54 of the armature in the direction of arrow a thereby tensioning clock spring 63. When armature 12 comes to a standstill in the position shown in phantom lines, the tensioning lever 55 still moves by a certain angle as a result of the inertia of its flywheel mass 58 until it stops at the stop 62 indicated by the phantom line position of tensioning lever 55. In this position pawl 59 engages the teeth 61 of the wheel 57, thereby coupling the tensioned clock spring 63 with the

clockwork

64, 65. As soon as the tensioning lever 55 has left contact roll 54, the magnet coil 3 becomes currentless. The armature 12 is brought back by means of spring 6 into starting position and it remains there until the

clockwork

64, 65 driven by spring 63 has run down and the tensioning lever 55 again runs up against roll 54. With the current connection thus restored, the aforedescribed operation is repeated.

FIG. 4 illustrates an embodiment incorporating a pole piece 13 of convex curvature which is engaged by an armature 14 having a concave curvature of lesser concavity caused by a greater radius of curvature than the pole piece 13. A shaped spring 11 is also used for guiding and resetting.

The embodiment illustrated in FIG. 5 by contrast shows a plane pole piece 4 and an armature 15 having a convex configuration at whose approximate center there is an extending arm 16 mounted thereupon. A guide rod 18 is pivotally connected to and acts upon the end of the arm 16 at the pivot point located at the center of curvature 17 of the armature 15. The rod 18 together with three rollers 19 located fixedly relative to the surrounding space provides appropriate rectilinear guiding for controlling movement of the pivot point 17. The motion of the guide rod 18 is limited by

stops

20 and 20a. A helical tension spring 21 is provided for resetting. An additional stop 22 is provided on the cup 2 for direct bearing thereon of the armature 15 in the starting position.

The further example illustrated in FIG. 6 has a pole piece 23 of concave curvature and an armature 24 of corresponding convex curvature but with a somewhat smaller radius of curvature. At its center of curvature 25 the armature is hinged on a lug 26 which is pivotable about the stationary pivot 27 of the pole piece 23. A leaf spring 28 mounted on one side of the armature 24 near the starting position 7 of the rolling motion and on the other side on a position 29 stationary relative to the ambient space is provided for resetting and additional guiding. In order to provide the least possible obstruction to the close bearing of the armature 24 upon the pole piece 23 intended by the choice of similar curvature radii, it is possible for a small groove 30 to be provided in the armature for accommodating the leaf spring 28. The lug 26 in conjunction with the resetting spring 28 provides advantageous guiding for the armature 24.

FIG. 7 represents a variation of the preceding embodiment but being no less advantageous. In this embodiment the pole piece 23 and the armature 24 are provided with

alternate teeth

31 and 32 which enmesh on rolling. A leaf spring 34 is provided for resetting into the starting position limited by a stop 33.

FIGURES 8 and 8a show in particular in the two limiting positions and to an enlarged scale the rolling surface of pole piece and armature of an embodiment representing an improvement relative to the example illustrated in FIG. 6. In this embodiment the rolling surface of the pole piece 23 is divided into two

sections

35 and 36 of arcuate form while the rolling surface on the armature 24 represents a single section of arcuate configuration. The radius of curvature of the section 35 disposed forwardly in the direction of the rolling motion is larger than and the radius of curvature of the other section 36 is equal to the radius of curvature of the rolling surface of the armature 24. As indicated in FIG. 8a, the armature 24 bears completely upon the inner section 36 when said armature is in the attracted position.

FIG. 9 represents a first example of an embodiment with an armature constructed as a resilient strip. 37. The strip 37 may be constructed from a resilient plastic material which has been rendered magnetizable by the insertion of soft iron particles. Its end 38 is secured to the cup 2 and is provided at its other end with an eyelet 39 for connection to the mechanism to be actuated. In the static position the spring strip 37 is straight. When current is switched on it bears upon the curved pole piece 13 as indicated by the broken lines.

FIGS. 10 and 11 show two modifications. In the first of these the pole piece 13 is also curved and the spring strip 40 is pre-bent in approximate adaption to the aforementioned curvature. In the last-mentioned modification the pole piece 4 is planar and the spring strip 41 is curved away from the pole piece 4 when it is in its starting position.

FIG. 12 illustrates an example in which the pole piece 13 is once again constructed in curved form. The strip 42 is maintained tensioned in a rigid cradle 44 by means of a resilient section 43, the cradle 44 being pivoted by means of trunnions 45 on the bearing pedestal 46 so that said strip 42 touches the pole piece 13 at the starting position 7 of the rolling motion. When current is switched on the strip 42 together with the cradle 44 is attracted and bears resiliently and progressively upon the pole piece 13. It is also possible to employ with advantage a flexible soft iron strip which is tensioned by a resilient cradle.

As shown in FIG. 13 the strip 47 may be constructed from a non-magnetic resilient material. The strip 47 is preferably constructed of a non-magnetic metal and is provided with individual soft iron pieces 48 disposed closer adjacently in line. A greater force effect is obtained thereby when compared to a thin self-magnetiza'ble strip.

To increase the flexibility of the strip this may also be provided with recesses 49 formed in the edge thereof.

5 This is illustrated in an enlarged scale in FIG. 14. A ladder strip in which webs 51 remain between recesses 50 as indicated in FIG. 14a serves the same end.

FIGS. 15 and 15a illustrate an arrangement wherein a strip armature has soft iron members 52 welded between two plastic strips 53.

A latitude of modification, substitution and change is intended in the foregoing disclosure, and in some instances, some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

I claim:

1. An electromagnetic actuating apparatus comprising an electromagnet including a solenoid core provided with a pole piece, and a movable armature, said armature and said pole piece having corresponding surfaces in continuous rolling contact, both of said corresponding surfaces being curved, the radii of curvature of said corresponding surfaces differing only slightly.

2. An apparatus according to claim 1, wherein the surface of said pole piece comprises two circular arcs of different radius, said surface of the armature is curved in a single circular arc, the radius of the part of the pole piece disposed forwardly in the direction of said continuous rolling contact being larger than the radius of curvature of the armature, the radius of the adjacent curvature of the pole piece being equal to the radius of curvature of the armature.

3. An electromagnetic actuating apparatus comprising an electromagnet including a solenoid core provided with a pole piece, and a movable armature, said armature and said pole piece having corresponding surfaces in continuous rolling contact, said pole piece and said armature being provided with complementary intermeshing teeth.

4. An electromagnetic actuating apparatus comprising an electromagnet including a solenoid core provided with a pole piece, and a movable armature, said armature and said pole piece having corresponding surfaces in continuous rolling contact, said armature being of a resilient strip for progressively bearing upon said pole piece, said 5 strip being formed of a non-magnetic material, and a plurality of discrete soft iron members bonded to said strip.

5. An apparatus according to claim 4, wherein said strip is provided with recesses for increasing its flexibility.

6. An apparatus according to claim 5, wherein said pole piece has a curved surface.

7. An electromagnetic actuating apparatus comprising an electromagnet including a solenoid core provided with a pole piece, and a movable armature, said armature and said pole piece having corresponding surfaces in continuous rolling contact, said armature including a pair of resilient plastic strips, and a plurality of soft iron members disposed between and bonded to said strips.

8. An apparatus according to claim 1, wherein said armature and said pole piece are in physical contact in the static condition at the starting position of said continuous rolling contact.

References Cited UNITED STATES PATENTS 2,120,178 6/1938 Hausrath 335--270 XR 3,051,988 9/ 1962. Baermann 335303 XR FOREIGN PATENTS 688,832 6/1940 Germany.

G. HARRIS, Primary Examiner US. Cl. X.R. 335--279