US3420562A

US3420562A - Magnet holder for door closures and the like

Info

Publication number: US3420562A
Authority: US
Inventors: Peter Simon
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-08-31
Filing date: 1967-08-25
Publication date: 1969-01-07
Anticipated expiration: 1986-01-07
Also published as: AT286817B

Description

Jann?, 1969 P, S|MON 3,420,562

MAGNET HOLDER FOR DOOR CLOSURES AND THE LIKE Filed Aug. 25, 1967 Sheet of 3 Jan. 7, 1969 P. slMoN 3,420,562

MAGNET HOLDER FOR DOOR CLOSUR S AND THE LIKE Sheet Filed Aug. 25, 1967 Jan. 7, 1969 P. slMoN 3,420,562

MAGNET HOLDER FOR DGOR CLOSURES AND THE LIKE Filed Aug. 25, 1967 Sheet 3 lo1 5 F' .11 12 @el Inventor:

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I L n United States Patent O 3,420,562 MAGNET HOLDER FOR DOOR CLOSURES AND THE LIKE Peter Simon, Schramberg, Germany, assignor to Karl Simon, Schramberg, Germany Filed Aug. 25, 1967, Ser. No. 663,308 Claims priority, application Germany, Aug. 31, 1966, S 105,614; Apr. 13, 1967, S 109,310 U.S. Cl. 292-2515 31 Claims Int. Cl. Ec 17/56; E05c I9/16 ABSTRACT OF THE DISCLOSURE Magnet holder for door closures and the like which comprises in combination a housing; a magnet assembly disposed in said housing; an armature plate forming part of said magnet assembly; at least one pole piece arranged for contacting said armature plate under the action of the coersive power of the magnet; an abutment plate for bracing the magnet during its action, the said abutment plate being deflectably disposed in said housing opposite said armature plate so as to permit the Ibase line of the abutment plate to shift in a plane about parallel to the direction of the coersive action of the magnet; abutment surfaces provided on said abutment plate, at least one of said abutment surfaces thus being adapted, upon deflection of said abutment plate, for limited movement relative to said housing; and stop means on said magnet assembly for cooperating with said abutment surfaces.

BACKGROUND OF THE INVENTION Magnet holders are known for door closures and similar articles in particular furniture doors in general which comprise a permanent magnet system of which pole pieces can contact an armature plate which is fastened to the door or the door frame.

The magnet system in this type of magnet holder consisting of two parallel pole pieces and a permanent magnet arranged between the pole pieces is usually disposed in a housing which is penetrated at its frontal wall partly 'by the pole pieces. The pole pieces have stops at opposite sides which abut in a close t the inside yface of the stationary and rigid frontal wall of the housing. The magnet system therefore cannot move and the pole pieces can come into full contact with the armature plate only if the armature plate is exactly parallel to the Contact faces of the pole pieces. Such alignment usually is not accomplished since door and door frame are apt to get warped. A mounting true to the angle involved of the magnet holder and of the armature plate at the furniture parts is usually not possible.

To avoid these diiculties it has been proposed to use armature plates which are arranged in a special armature plate holder for limited angular movement. This kind of structure however is rather complex and has a comparatively great height so that it is diicult to mount.

It has also `'become known to use instead of the movable armature plate a rigid thin plate Awhich is attached to the furniture part and instead to mount the magnet system lfor movement in the magnet holder housing. A magnet holder of this type which is on the market has a magnet system which is provided with a rod-shaped pivot which extends from pole piece to pole piece and which rests against the projection of the rigid housing face which projection is directly inwardly and serves as an abutment. This structure likewise is rather complex and expensive. Besides in order to prevent a dropping out of the magnet it is necessary to enclose the housing from all sides which again results in complications during the manufacture.

3,420,562 Patented Jan. 7, 1969 ICC SUMMARY oF THE INVENTION It is therefore an object of the invention to form a magholder which is provided with a magnet system that is disposed for limited oscillation in a housing in order to cause the pole pieces at all times to make close tting contact with the armature plate.

Itis a more general object of the invention to avoid the shortcomings of the known magnet holders of this type.

It is furthermore an object of the invention to provide for a simplified structure which can be manufactured easily and is adapted to have substantial coercive powers and a substantial reliability of operation.

The invention has also the object to iform a magnet holder of the type indicated which consist-s only of comparatively few parts and can easily be assembled without special tools.

These objects are met `by a magnet holder comprising, in combination a housing; a magnet assembly disposed in said housing; an armature plate forming part of said magnet assembly; at least one pole piece arranged for contacting said armature plate under the action of the coersive power of the magnet; an abutment member for bracing the magnet during its action, the said abutment memlber being deectably disposed in said housing opposite said armature plate so as to permit the base line of the abutment member to shift in a plane about parallel to the direction of the coercive action of the magnet; abutment surfaces provided on said abutment member, at least one of said abutment surfaces thus being adapted, upon deection of Isaid abutment member, for limited movement relative to said housing; and stop means on said magnet assembly for cooperating with said abutment surfaces.

The novel features which are considered as characteristic for the invention are `set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objections and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a part, diagrammatic view of a furniture door and the magnet holder shown in closing position by way of one embodiment of the invention;

FIG. 2 is a front view of the magnet holder of FIG. l;

FIG. 3 is a cross section through the magnet holder of FIG. 2 along lines 3 3;

FIG. 4 is a cross section through the magnet holder of FIG. 2 along lines 4--4;

FIG. 5 is a bottom view of the housing of the magnet holder shown in FIG. 2 after removal of the magnet assembly from the housing;

FIG. 6 is an exploded perspective view of the magnet assembly of the magnet holder of FIG. 2;

FIG. 7 is a top view of the abutment plate of the magnet holder of FIG. 2, the abutment plate being under the coercive power P of the magnet which is not shown;

FIG. 8 is a Side View of the abutment plate of the magnet holder of FIG. 2, the abutment plate being under the coercive action P of the magnet (not shown);

FIG. 9 shows a modication of the front wall of the magnet holder of FIG. 2;

FIG. 10 shows another modication of the front wall of the magnet holder of FIG. 2;

FIG. 1l is a bottom View of the other embodiment of the magnet holder;

FIG. 12 is a section through the magnet holder of FIG. 11 along lines 12-12;

3 FIG. 13 is a front view of the magnet holder of FIGS. ll and 12;

FIG. 14 is an exploded perspective view of the ma-gnet assembly of the magnet holder of FIGS. 1l to 13; and

FIG. 15 is an enlarged perspective view of a detail of the magnet holder of FIGS. l1 to 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As has been stated above, the abutment in this case is provided in the front wall of the housing. This results in a particularly simple and reliable structure. It is very easy to assemble this type of magnet holder and the abutment plate can support comparatively high coercive force in spite of a relatively thin structure. A further advantage is that there is obtained almost frictionless oscillation of the magnet system. It is therefore easier to accomplish a smooth abutment of the magnet parts to the armature plate. In many cases this will result in a higher coercive force at the same strength of the permanent magnet.

The abutment surface preferably is formed rigidly and more preferably formed in one piece with the abutment plate.

A particularly preferable embodiment consists in a magnet holder where the abutment plate is disposed in an opening in the front wall of the housing. It thus forms part of the front wall itself. The abutment plate preferably is formed in one piece with the contiguous stationary housing parts. The housing and the abutment can for instance be formed as one part by casting or spraying from a synthetic material or other suitable structural substance. The` housing can be formed in the structure of the invention in the manner that the magnet assembly is self-supporting without the requirement of a separate bottom plate for the housing. This can be accomplished particularly by using a rib-like projection in the rear wall of the housing. The magnet holder of the invention thus is characterized by a minimum of parts. The housing for instance can be formed by a spraying process without the requirement for subsequent further finishing. l

The magnet system preferably comprises a magnet and two plate-like pole pieces, the magnet being held between the pole pieces. This is the advantage that the magnet systern can be assembled without further equipment and that first one pole piece and the permanent magnet and then the other pole piece can successively be introduced into the housing. Preferably, the stop places are provided only at the pole pieces while the permanent magnet itself is force-locked between the pole pieces. If the magnet system is formed of one piece or if the pole pieces are rigidly connected to the permanent magnet it is of course possible also to provide for a stop on the permanent magnet itself. The movability of the abutment surfaces provided on the abutment plate can be affected in many different ways. Frequently it is preferable to provide the abutment plate for oscillation in the housing. The journalling of the abutment plate can for instance be carried out by means of spring locks for instance in the form of strips or similar which can be formed for torsion or for bending and can be rigidly connected to a stationary part of the housing and to the abutment plate itself. The locks or strips can also be formed in one piece with the abutment plate and the housing. Their width, length and location must be arranged so that the required mobility of the abutment plate and of the abutment surfaces is effected. It may be advantageous to arrange the lugs by means of a universal joint for the abutment plate. Preferably, in this case there are four lugs which may be aligned in pairs. It is also possible to have two lugs arranged in pairs and still provide for a universal joint arrangement for the abutment plate and to provide for both torsional and bending movement of the lugs. Obviously, the oscillating disposition of the abutment plate can also be accomplished in other manners for instance by means of a separate pivot which is provided in a bore or similar. However, this kind of structure would have certain disadvantages compared with the previously indicated form.

It is a further preferred arrangement that at least part of the abutment plate is formed with at least one springy abutment surface in order to provide `for at least some of the required movability. This will result in a particular simplified structure. The magnet system in order to obtain a smooth close contact with the armature plate must be adapted for oscillating movements about two pivot axes which are directed at right angles to each other or in other words it must be arranged to have two degrees of pivot movement. The axes should extend about parallel to the front face of the housing. This can be accomplished easily in the magnet holder of the invention. It is not necessary in this case to have pivots as physical parts. The disposition of the pivot axes relative to the housing need not be immovable since the definition of the movability of the magnet system by means of the mentioned axes is merely a theoretical assumption. However, all this does of course not exclude that there may lbe physical parts constituting pivots vfor the abutment plate.

The lmagnet system in a preferred embodiment rests on at least three and more preferably four abutment surfaces provided in the abutment member which preferably is formed as a plate, the several abutment surfaces forming the corner points of the polygon of the abutment member. Generally, the polygon should .be plane, but it may also be three-dimensional. This provision of abutment surfaces has the advantage that no separate pivots for the stop points are necessary. A particularly simple form of abutment member is possible if the abutment member has only a single abutment base line. Abutment base line in this connection means the connecting line between two spaced abutment surfaces. If one of the abutment surfaces is substantially linear then the abutment base line is formed by the longitudinal center line of this linear abutment surface. The term is to be understood in this manner throughout the specification.

Preferably, there are two spaced abutment surfaces, one for each of the pole pieces. The abutment surface may be in form of a linear plane surface or it may be in form of two aligned surfaces. In case that there are several different abutment base lines it is possible to provide -for a suitable number of abutment surfaces along this line. It is preferred that the magnet system has a limited degree of oscillation about the abutment base line. This will permit a really smooth close fitting with the armature plate when used in connection with the oscillation of the abutment base itself.

A particularly preferred form provides for a ribbonlike strip in the front face of the housing preferably in an opening in that front face. In this embodiment at least one abutment surface is provided for the abutment base line. The strip is formed in a manner that the abutment surface can elastically yield to the coercive force exerted by the magnet assembly. The length of the strip preferably is larger than its width and the Strip may be connected rigidly at its narrow sides to the housing or may be fastened thereto. The strip can also be subdivided in several parallel segmental strips in which case each of these segmental strips should have at least one abutment surface. It is preferable for the oscillation of the abutment that the abutment base line is procided in the center of the strip and that it extends parallel to the narrow sides of the strip if there is no force exerted upon the strip.

The abutment and its suspension can be formed of any suitable material, preferably of a synthetic material with good elastic properties. For instance a plastic such as an acetal resin made of polymerized anhydrous formaldehyde (polyoxymcthylene) may `be used for this pul.` pose.

Now referring to the drawings which illustrate particular embodiments the following is noted.

In FIG. 1, indicates the door of a `furniture piece and 11 indicates the door frame. An armature 12 consisting of sheet steel is fastened to the door by means of a screw 13. A magnet holder 14 is likewise fastened to the door frame 11 by means of screws such as indicated at 15. A magnet assembly 21 is provided in the magnet holder 14 comprising

pole pieces

16 and 17 which abut with their plane contact surfaces 18 and 19 (FIG. 2) smoothly to the armature plate by virtue of the oscillating arrangement.

The magnet holder 14 which has illustrated in greater detail in FIGS. 2 to 8, comprises a lhousing 20 in which the magnet assembly 21 is disposed to permit oscillation thereof. The housing has an inner space 22 and an open floor as well as a ceiling 23, a frontal wall 24, a rear wall 25 and two

side walls

26 and 27. The usual shoulders for

fastening purposes

28 and 29 are provided on the housing and longitudinal slots 30 are provided through which the holding screws 15 extend.

A central rib 3-1 is disposed in the rear wall 25. The magnet in released condition will abut against this central rib 31 and will thus be prevented from dropping out of the housing without causing any difficulties to the successive introduction of the various parts of the magnet assembly during mounting. Two wedge-like projections 32 are provided in the ceiling 23. The protruding portions 33 which are close to the face wall 24 also serve as support plates to the magnet assembly 21 without interfering with its oscillation. The projecting portions 33 are therefore disposed slightly above the upper edge 35 of an opening provided in the frontal wall through which the pole piece 16 of the magnet extends. The frontal wall of the housing has a stationary part and a movable abutment member in the form of an abutment plate 41 which parts both are plane and of equal thickness. Both parts are formed in one piece by means of

central ribs

42, 42 which permit oscillation of the abutment 41 that is located in the opening of the frontal wall 24 about an axis 70. The abutment member y41 has two

rectangular apertures

36 and 39 for the

pole pieces

16 and 17. The abutment member is disposed itself in a rectangular opening of the stationary part `40 of the front wall at a small spacing from the circumferential Wall 43 of the aperture.

The circumferential walls of the

openings

36 and 39 surround the

pole pieces

16 and 17 in a substantially close iit and therefore form an additional support for the magnet assembly 21.

The magnet system 21 itself comprises a parallelepipedon shaped permanent system and two

pole plates

53 and 54 that are force-locked on its plane faces of the

magnets

51 and 52. The pole plates can also be rigidly connected to the permanent magnet 50, however the assembly will be easier if they are merely locked by force to the magnet 50.

The two pole plates are of even shape and are provided on opposite sides each with two stepped ledges. The ledges are indicated by the

reference numbers

55, 55", 55"', 56, 56', S6, and 56 and their purpose will be further discussed below. The

pole pieces

16 and 17 themselves form parts of the

pole plates

53 and 54.

Four abutment surfaces to 63 are provided in the rear face of the abutment plate 41 next to the

apertures

36 and 39 for the

pole pieces

16 and 17. The abutment surfaces are part of the abutment plate and form the corner points of a rectangular polygon. The stops provided on the magnet pole plates in the form of stepped

ledges

55, 55', 55", and 55" are provided for abutment to the abutment surfaces in response to coercive -action of the magnet.

In this embodiment there are provided parts of the abutment plates as

spring tongues

46 and 47. These are the parts laterally of the oscillation axis 70. These spring tongues are adapted to be bent and twisted out of the frontal plane of the housing under the coercive action P of the magnet. This bending and twisting is in addition to the twisting of the

ribs

42 and 42. This enables the oscillation of the base line of the abutment which is formed by the abutment surfaces of the abutment plate as has been explained. This is particularly illustrated in FIGS. 7 and 8. The frontal plane of the housing is indicated as 44. As is shown in FIGS. 7 and 8, the flexibility of the

tongues

46, 47 results in the pivoting of the base of the

abutment plate

41, 45 about the pivot axes 70 and 71 shown in FIG. 2. Additionally there is the oscillation of the ribs 42 and 42' which is of advantage in view of the comparatively extended width of the magnet system.

The

ledges

56, 56', 56, and 56" of the pole shoes 53 and 54 are provided in a manner to form abutments which are supported on the inner faces 68 of the stationary part 40 of the frontal wall of the housing if the magnet system 21 protrudes or oscillates to a corresponding degree from the frontal plane. Thus, an overloading of the abutment and its suspension upon opening of the door 10 will be prevented.

The magnet system 21 in the FIGS. 2 to 8 rests against the rib 31 only when not in action. As soon as the coercive force is exerted in the direction of the arrow A (FIG. 4) the magnet system will be lifted from the rib 31 (FIG. 4) and can then oscillate practically without friction in the described manner. Thus, the coercive force can have its maximum effect.

The magnet holder shown in FIG. 9 corresponds in all details to the described embodiment except that the

ribs

42 and 42"' are of greater extent. The same reference numbers are therefore used in this figure. The extension of the ribs beyond that shown in the previous figures has the advantage that in itself this permits an oscillation of the magnet system about its two axes 70 and 71 (FIG. 2) since the ribs act not only as torsion springs but also as leaf springs. Thus, the ribs 42" and 42 as well as the

tongues

46 and 47 have the effect to provide for a journalling of the magnet system which has two freedoms of oscillation. These two effects are added and each oscillating system is therefore under less strain. In certain cases of course only one of these oscillations or deflections will be suiicient.

The desired flexibility of the above abutment member can also be obtained by a universal joint suspension of the abutment as indicated in FIG. 10. This would be the case if for some reason it was desired to form the abutment as a substantially rigid plate. The rigid abutment member 41 of this figure is disposed in a ring 73 which forms part of the frontal wall by means of the

central ribs

42a, 42b, thus permitting oscillation around a pivot axis 7 0. The ring 73 in turn is provided for oscillation on the stationary part 40 of the frontal wall 24 of the housing 20 by means of the two central ribs 74 and 74', the oscillation taking place around the pivot axis 71 which is at right angles to the pivot axis 70. In other respects the magnet holder of which the abutment surfaces are indicated as 60' to 63 and the pole pieces as 16 and 17 is similar to the previous embodiment and does not require further explanation.

The magnet holder which is shown in FIGS. 11 to l5 shows a housing 20' in the form of a parallelepipedon in which the magnet system indicated as 21 is located for oscillation. The housing has a floor 12 in which an opening 34 is provided and which has the frontal wall 24", a rear wall 25', a ceiling 23', and lateral walls 26' and 27.

Longitudinal apertures

37 and 38 are provided in the lateral walls to permit the application of screws by which the magnet holder can be fastened on the furniture piece.

The magnet holder 21 has a permanent magnet in the form of a parallelepipedon 50 which is made of an oxide-ceramic material and which has pole surfaces 51', 52' provided on the

pole plates

53 and 54 madev of soft iron and held by force-fit. Each pole plate has a

pole piece

48, 49 and each pole piece has a slotted

aperture

66, 67 and is thereby subdivided into two

segments

75, 78 of equal form and equal polarity. The bottom of each opening forms a support for a stop 66', 67 for the magnet system in cooperation with the abutment 72 as will be explained further below. Both stops are located in a plane of symmetry of the magnet system which is at right angles to the planes of the pole pieces and pole surfaces 18' and 19'. The width of the pole pieces is substantially greater than the distance between them.

The pole pieces protrude through

longitudinal slots

79 and 80 provided in the front wall 24 of the housing. The upper longitudinal edge 81 of the slot 79 is formed by an edge of the stationary housing in order to facilitate assembly is flush with the inner face 82 of the ceiling 23. This inner face 82 extends from the longitudinal edge 81 in the direction towards the rear wall 25 of the housing and slants upwardly in order to permit oscillation of the magnet system in direction of the arrow B. The assembly of the magnet holder is affected by rst introducing the pole plate 54 in the housing into the position shown in FIG. 12, then placing upon it the permanent magnet 50 and finally introducing the pole plate 53.

A ribbon-like strip 90 extends between the pole plates and is provided with two

elastic ribs

90 and 90 and is connected in one piece at its

small sides

91 and 92 with the housing. In the center it has two lateral pro truding ends 93 and 94 which extend into

apertures

66 and 67 of the pole plates. Semi-circular curved rib-like abutment surfaces 95 and 96 are provided on the rear sides of the protruding projections as shown in FIG. 15. These abutment surfaces 95 and 96 are in alignment and the

stops

66 and 67 of the pole plates can be caused to come in Contact with them during the oscillation. The abutment surfaces 95 and 96 are clearly shown in FIG. 15 which is an enlarged part perspective rear view of the abutment 93. These support surfaces define a base line 97 of the abutment Iwhich is adapted to adjust itself in the direction of the arrow F in a slanting way towards the frontal `wall by means of the torsion effects on strip 90. The

projections

93 and 94 have the effect that the base line of the abutment is longer than the width of the strip 90 which is favorable for the operation of the device. The abutment surfaces 95y and 96 are formed as one coherent rib to facilitate the manufacture.

The abutment surfaces 95 and 96 of the abutment form oscillating pivots for the magnet system. The magnet system therefore is adapted for limited oscillation in the direction of the double arrow C (FIG. l1) about the base line 97 of the abutment. It can thus adjust itself in a second plane of oscillation which is at right angles to the previously mentioned first plane of oscillation and parallel to the armature plate. Thus, an optimum contact or abutment between the magnet system and the armature plate is always effected. Spaces are provided between the inner faces 98 and 99 of the housing in the pole plates which spaces are sufliciently large so that the magnet system can oscillate laterally in the direction of the double arrow C as necessary.

A semi-circular curved rib 85 is provided on the rear face 89 of the inside of the housing. This rib is also a pivot for the oscillation of the magnet system which is also favorable for the journalling of the magnet system in the housing and does not in any way interfere Iwith the pivoting about the abutment surfaces 95 and 96.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

What is claimed is:

1. A magnet holder for door closures and the like, the said magnet holder comprising a housing; a magnet assembly disposed in said housing; an armature plate coacting with said magnet assembly; at least one pole piece arranged for contacting said armature plate under the action of the coercive power of the magnet; an abutment member having at least one base line and bracing the magnet assembly during its action, the said abutment member being deectably disposed in said housing opposite said armature plate so as to permit at least said one base line of the abutment member to shift in at least one plane about parallel to the direction of the coercive action of the magnet; at least one abutment surface provided on said abutment member, the said abutment surface thus being adapted for limited movement relative to said housing upon deliection of said abutment member; and stop means on said magnet assembly for cooperating with said abutment surface.

2. The magnet holder of claim 1 wherein at least one abutment surface forms part of the abutment member.

3. The magnet holder of claim 1 wherein an opening is provided in the front wall of the housing opposite the armature plate and wherein the abutment member has the form of a plate and is disposed in said opening.

4. The magnet holder of claim 1, wherein the abutment member is formed in one piece with the contiguous parts of the stationary housing.

5. The magnet holder of claim 1 wherein apertures are provided in the front wall of the housing opposite the said armature plate and wherein the magnet assembly includes pole pieces that penetrate -through said apertures `and wherein a support is provided in the rear wall of the housing to prevent disengagement of the magnet and wherein the bottom of the housing is open.

6. The magnet holder of claim 5, wherein the support is disposed at the rear wall of the housing in the form of a rib-like projection.

7. The magnet holder of claim 1 wherein the abutment member and the housing are made of one piece.

8. The magnet holder of claim 1 wherein the magnet assembly includes pole plates carrying said pole pieces and wherein stop means are provided on the pole plates for cooperation with the abutment surfaces of the abutment member.

9. The magnet holder of claim 1 wherein the abutment member is disposed swingingly within the housing.

10. The magnet holder of claim 9 wherein the abutment member is connected with the housing by means of springy tongue pieces, the ends of the tongue pieces being connected at one end to the abutment member and at the other end to the stationary housing.

11. The magnet holder of claim 10 wherein at least one tongue piece is adapted for Oscillation by torsional movements.

12. The magnet holder of claim 10 wherein at least one tongue piece is adapted for deformation by bending.

13. The magnet holder of claim 1 wherein the abutment member is connected to the housing by a universal joint.

14. The magnet holder of claim 1 wherein at least one part of the abutment member carrying at least one of said abutment surfaces is formed of a springy material.

15. The magnet holder of claim 1 wherein four abutment surfaces are provided, said four abutment surfaces being arranged 'as the corner points of a polygon.

16. The magnet holder of claim 1 wherein longitudinal slots are provided in the abutment member, the pole pieces penetrating said slots and the abutment surfaces being disposed laterally of the said slots.

17. The magnet holder of claim 1 wherein two tongue `pieces are provided centrally on said abutment member and in alignment with each other, the said tongue pieces being connected to stationary parts of the housing and forming central pivot points for the oscillation of the abutment member.

18. The magnet holder of claim 1 wherein two lateral wings are provided on the abutment member extending in opposite directions parallel to the front wall of the housing, at least one abutment surface provided on each of said wings.

19. The magnet holder of claim 18, wherein the wings are adapted for torsional yand pivoting movements.

20. The magnet holder of claim 8, wherein recesses are provided in the pole shoes and wherein the stop means are disposed in said recesses.

21. The magnet holder of claim 20 wherein the recesses are centrally disposed on the pole pieces thus dividing the pole pieces into two about equally sized portions.

22. The magnet holder of claim 1 wherein at least one pivot is provided for supporting the magnet system for oscillations about an axis formed by the base line of the abutment member.

23. The magnet holder of claim 22 wherein the pivot is formed as a projection on the abutment member.

24. The magnet holder of claim 22 wherein two abutment surfaces are provided each serving as pivot supports for one of the pole plates of the magnet system.

25. The magnet holder of claim 22 wherein at least one pivot is disposed on the at strip extending between pole pieces of opposite polarity, the ends of the strip being rigidly connected to stationary parts of the housing, the strip being adapted for torsional movements.

26. The magnet holder of claim 1 wherein the magnet assembly includes two pole plates and wherein two stops are provided on each pole plate disposed at the lateral sides of the pole pieces.

27. The magnet holder of claim 26 wherein at least one stop is in the form of a stepped offset formed in the pole plate.

28. The magnet holder of claim 21 wherein lat least one base line of the `abutment member extends in a central plane of the magnet assembly.

29. The magnet holder of claim 1 wherein stops are provided as part of the magnet Iassembly for limiting the movement of the magnet assembly by cooperation with parts of the stationary housing.

30. The magnet holder of claim 1 wherein at least one aperture is provided in the front wall of the housing for said pole piece and wherein the aperture is in proximity to the ceiling rof the housing and wherein the inner face of the ceiling extends slanting upwards from the said aperture in the direction of the rear wall.

31. The magnet holder of claim 1 wherein at least one abutment surface is provided at the ceiling of the housing in proximity to the front wall thereof, the said abutment surface being adapted to support the magnet assembly.

References Cited UNITED STATES PATENTS 2,770,759 11/1956 Ahlgren 292-2515 X 2,896,991 7/1959 Martin 292-2515 3,294,433 12/1966 Granzow 292-2515 FOREIGN PATENTS 1,366,145 6/1964 France.

MARVIN A. CHAMPION, Primary Examiner. E. I. MCCARTHY, Assistant Examiner.