US1870753A - Magnet unit - Google Patents

Description

H. SACHS MAGNET UNIT Aug. 9, 1932.

Filed May 11, 1931 vI/II/IIIII INVENTOH M Patented Aug. 9, 1932 PATENT, OFFICE HUGO SACHS, OF LEIPZIG, GEBMANY MAGNET UNIT Application filed May 11,1931, semi No. 536,583, and in Germany May 15, 19:0.

The invention relates to a magnet unit with armature adapted to vibrate in both directions between oppositely disposed poles and adjustable relatively thereto, for use in lolpd speakers, gramophone pickups and the Units of this kind are already known, in which the poles of the magnet are adapted to be displaced in the direction of vibration of the armature and are influenced by springs.

Such adjustability of the poles in the direction of vibration of the armature has the following disadvantages. If the poles are spring influenced, they themselves tend to vibrate, and the armature thus sustains losses of energy. If the springs are not of exactly equal strength, the one pole shoe may move further away from the armature than the H other, so that, eventually, the armature may still be adhering to the one pole shoe while already out of contact from the other. The same result also occurs when the armature is not accurately centered between the poles, to effect which exactitude is essential in the known units.

According to the invention, these drawbacks are obviated by forming the armature wedge-shaped between the poles, the poles or pole-shoes themselves being also of corre sponding form, so that, by sliding or turning the poles, which are perfectly rigid in the direction of vibration of the armature, or bymoving the entire frame of the magnet, transversely relatively to the direction of vibration of the armature, the distance between the armature and the pole-shoes can be diminished or increased at will, without causing the spacing between the pole-shoes and the armature to be unequal.

Thus in the electromagnetic unit of the present invention, the armature adapted to oscillate in both directions is arranged be tween oppositely disposed pole-shoes which are rigidly mounted in relation to each other but are adjustable as a whole in relation to the armature.

In addition to the improved and more accurate adjustment obtained in accordance with the invention, the assembling of the 50 unit is considerably simplified.

Various embodiments of units in accord ance with the invention are diagrammatically illustrated in the accompanying drawing, in which Fig. 1 is a side elevation of one embodip5 ment, and

Fig. 2 is a transverse section through Fig. 1. i

Fig. 3 is a sectional front elevation of a modification, and

Fig. 4 a side elevation thereof.

Fig. 5 is a perspective View of a further modification; and

Fig. 6 is a perspective view of the assembled unit according to Fig. 5.

In the drawing, like parts are denoted by like reference characters.

In the embodiment illustrated in Figs. 1 and 2, a, a denote two magnets which are rigidly connected with pole-shoes b and c by means of screws 6, 0 respectively. The magnets a and a are movably secured to a frame 6 by means of screws and nuts 8, s mounted in slots 7' of the frame 6. G denotes a bracket connected to the magnets a, a to .which bracket is anchored the head f of a screw spindle f. The spindle f passes through a correspondingly screw-threaded hole 6 in the frame 6. The free ends of the pole-shoes b and 0 are wedge-shaped and mounted therebetween is a wedge-shaped armature cl which is secured to the frame 6 by means of a lugor bracket d fast with the frame e. 'The armature d is connected by means of rods 0 p g to the diaphragm of a loud speaker (not shown). 70 denotes the energizing coils for the armature 05.

The poleshoes Z), c are. provided with holes or slots which are larger in the vertical direction than the diameter of the shanks of the retaining screws 6, 0 so as to enable each pole to be separately initially adjusted so as to make contact with the armature (Z when the retaining screws .7), c are eased.

The operation is as follows The magnets a, a and pole-shoes b, 0 are initially so adjusted that the pole-shoes b and a contact completely with the Wedgeshaped armature d which is fixed in relation to the frame 6. The retaining screws b", a v

are thereupon tightened and the screw spindle f is turned until the desired air gaps are obtained between the surfaces of the armature d and of the pole-shoes b and c.

The screw bolts 8 are thereupon tightened and the unit is ready for use.

Since the pole-shoes b, 0 are rigidly con nected with the magnets a, a which in turn are rigidly interconnected, the whole forms the unit which can be displaced horizontally in relation to the armatured, leaving the air gaps between the armature (Z and the poleshoes I; and 0 respectively always equal.

Figs. 3 and a illustrate an embodiment in which a single magnet a and its rigidly attached pole-shoes b, 0 are adapted to be swungabout the two pivots h, h in the frame 0, whilst the wedge-shaped armature (Z is secured on the frame 6 as in the embodiment shown in Figs, 1 and 2, In this embodiment, the air gap between the armature d and poleshoes Z) and 0 is increased by turning the magnet in one direction relatively to the stationary armature and decreased by turn ing the same in the opposite direction.

A further embodiment is shown in Figs. 5 and 6 in which the entire magnet a, including its rigidly attached pole-shoes Z), c, is adapted to swing about the pivots z, i. The ends of the armature d in this construction, are

wedge-shaped in opposite directions between the respective poles, the faces of which are correspondingly shaped.

As will be obvious from the drawing and description, the adjustment of the poles is always transverse relatively to the direction of vibration of the armature, and owing to the rigid mounting of the poles or pole-shoes thereby permitted, losses which would otherf wise occur through vibration of these mem-V bers themselves are precluded. Moreover, springs and the like are entirely dispensed with, and the wedge-shape of the armature enables very accurate adjustment to be effected,

I claim I 1. An electromagnetic unit for use in loud speakers, gramophone pickups and the like, comprising a frame, a magnet, pole pieces with oblique ends rigidly attached to the poles of said magnet with their oblique ends facing each other and converging, a vibratory-armature of a shape corresponding to the gap between the oblique ends of said pole pieces, located between said oblique ends and resiliently supported on said frame, energizing coils co-operating with said armature, and means for moving said pole pieces as a unit transversely to said armature to ensure equal adjustment of the :air gaps between comprising a frame, amagnet, pole-pieces with oblique ends rigidly attached to the poles of said magnet with their oblique ends facing each other to leave a wedge-shaped air gap, a vibratory wedge-shaped armature,

located between said oblique ends and resiliently supported on saic. frame, energizing coils cooperating with said armature, and means for moving said pole pieces as a unit transversely to said armature to ensure equal adjustment of the air gaps between each face of the armature and the corresponding oblique face of the pole piece.

3. An electromagnetic unit for use in loud speakers, gramophone pickups and the like, comprising a frame, a magnet, pole pieces with oblique ends rigidly attached to the poles of said magnet with their oblique ends facing each otherto leave a wedgeshaped air gap, a vibratory wedge-shaped armature, located between said oblique ends and resil iently supported on said frame, energizing coils cooperating with said armature, and a screw spindle for moving saidmagnet and the pole pieces as a unit transversely to said armature to ensure equal adjustment of the air gaps between each face of the armature and the corresponding oblique face of the pole piece.

4:. I Anelectromagnetic unit for use in loud speakers, gramophone pickups and the like, comprising a frame, a magnet, pole pieces with oblique ends rigidly attached to the poles of said magnetwith their oblique ends facing each other to leave wedge=shaped air gap, a vibratory wedge-shaped armature located between said. oblique endsand resiliently supported on said frame, energizing coils co-operating with said armature and pivots pivoting said magnet and pole pieces as a unit transversely to said armature to 7 ensure equal adjustment of the air gaps between each face of the armature and the corresponding oblique face of the pole piece.

5. An electromagnetic unitfor use in -loud speakers, gramophone pickups and the like, comprising a frame, 7 a magnet, pole pieces with two pairs of oblique ends attached to the poles ofsaid magnet with each pair of oblique ends facing each other to leave wedge shaped air gaps, a vibratory armature with its ends wedge-shaped located between said oblique ends and resiliently supported on said frame, energizing coils co-operating with said armature, and pivots pivoting said magnet and pole pieces as a unit transversely to said armature to ensure equal adjustment of the air gaps between each face of the armature and the correspending oblique face of the; pole piece. I

In testimony whereof, I ailix my signature.

' nueo SACHS,

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