US1978583A - Electrical pick-up apparatus - Google Patents

Description

Oct. 1934. c K'ENTNER 1,978,583

ELECTRICAL RICK-UP APPARATUS Filed Nov. 14, 1951 I N V E 16R. Cqrro U. D. fi entner;

I- r HIQSATTORNEY. 2

Patented Oct. 30, 1934 PATENT OFFICE ELECTRICAL PICK-UP arrm'rus I Carroll D. Kentner, Collingswood, N. .L, assigncr to Radio Corporation of America, a corporation of Delaware Application November 14, 1931, Serial No. 574,961

' 6 Claims. (01. 84-408) My invention relates to improvements in electrical pick-up apparatus l adapted, particularly,

for embodimentin electrical musical systems,'

such as electric carillons, chimes, pianos, and the like.

In systems of the character referred to, a single note is sounded by striking a suitable vibratory member, associated with an electrical pick-up device. This member forms part of a magnetic circuit and, upon vibrating, causes a current wave to be developed in the pick-up coil, corresponding t0 the note to which the member is tuned. The

note is made audible by amplifying the current wave and supplying the same to a loudspeaker.

In constructing an electrical musical instrument having a relatively large number 01 units to produce as many different notes, there is the problem oi arranging and supporting the large number of pick-up devices in a compact and convenient way without giving rise to a condition wherein operation of any one device will, on account of its close mechanical association with the others, cause one or more of the same to operate at least in some degree and, thereby, to produce an accompanying and undesirable note along with' the particular note being sounded at the time. This undesirable eflect has been attributed to the mechanical transmission of. vibration from the operated device to one or more or the others supported in close proximity thereto and to the phenomenon of mutual inductance between adiacent device's. These difliculties increase as the individual pick-up devices are arranged closer together to obtain the best advantage in the way of compactness of construction.

with the foregoing in mind, it is one of the objects oi my invention to provide improved pickup apparatus, 01' the character referred to, which I comprises any desired number of individual pickup devices, the supporting structure and the construction and arrangement of the various parts of the individual devices being such that the same may be arranged conveniently in bank formation and in close proximity to each other to obtain the best advantage as regards compactness and sime plicity of construction while, at the same time,

preventing operation, in any eiiective degree, of

Figure 1 is a fragmentary, perspective view,

partly in section, oi. electrical pick-up apparatus embodying my invention, one of the parts being removed;

Fig. 2 is an elevational view, partly in section, looking toward the right in Fig.1; and

Fig. 3 is a diagrammatic, perspective view of an electric carillon system embodying the pick-up apparatus shown in Figs. 1 and 2.

In Fig. 1, three of the pick-up units, constructed in accordance with my invention, are designated, respectively, by the reference- numerals 10, 11 and 12. These units, as shown, are arranged in row formation, spaced from each other, and are provided, respectively, with vibratory members 13, 14 and 15 having different periods of vibration corresponding to different notes in the musical scale.

As these units are of identical construction, description of one will suiiice for all. With reference, more particularly, to'Fig. 2, the. unit 10 comprises complementary pole elements 16 and 17, having pole portions 18 and 19. The pole elements 16 and 1'7 are secured. by bolts 16a and 17a to a nonmagnetic supporting member-21. The pole elements are provided with shoulders 22 and 23 which fit the adjacent edges 01' the member 21, whereby the latter acts as a gauge or spacing member to hold the pole elements in fixed relation with their pole portions 18 and 19 spaced properly to provide an air gap 241.

By reason or the close fit of the shoulders 22 and 23 with the edges of the member 21, the pole elements 16 and 17 are held against pivotal move ment about the axes of the securing bolts 16a and 17a.

A pick-up coil 25 is disposed, as shown, be a For the purpose of holding the member 13 in flxedposition for tree vibratory movement without contacting with thepole portions 18 and 19, the coil 25, or the edge oi the opening 29, an L-shape supporting member 9 is secured to the pole element 1'7, for which purpose this member is tapped to receive the threaded end of the bolt 170 which passes loosely through the member 21 and the pole element 17. The tip 300! the end portion 28 is clamped between a block 81 and the member 9, for which purpose the latnected in parallel in the material.

ter is adapted to receive bolts 32. By unscrewing the bolts 32, the straight, end portion 28 of the member 13 can be adjusted longitudinally to change the period of vibration and therefore the note produced.

The member 13 is caused to vibrate upon being struck by a peg 33 of suitable nonmetallicmaterial, such as gut or wood, which rests upon a core 34 of magnetic material. These parts have a free fit in the central opening of a solenoid winding 35, which, upon being excited, causes the core to move almost instantly to the center of the winding, whereupon the peg 33 strikes the member 13 sharply to cause the same to vibrate.

The member 9, the block 31 and the bolts 32 are made of brass or other suitable nonmagnetic As shown in Fig. 1, the supporting member 21 is common to the units 10, 11 and 12, and supports the same in row formation, adjacent units being spaced only a relatively short distance from each other to obtain the advantage of compactness.

The supporting member 9, also, is common to the various units, and operates to support all of the vibratory members 13, 14 and 15.

A suitable horse-shoe magnet 36 embraces the member 9 and the associated parts, as shown, and remains in position by reason 015 its attraction to the pole elements 16 and 1'7.

For the purpose of utilizing my improved pickup apparatus in a system for playing a tune,

chimes, or any desired sequence of musical notes,-

the individual units may be connected as shown diagrammatically in Fig. 3, wherein the pick- up coils 25, 37 and 38 of the units 10, 11 and 12, respectively, are connected in series, the series being connected as shown in the input circuit of a suitable amplifier 39. The amplified current waves are caused to p'ass through the usual electromagnetiocoils 40 of loudspeakers 41, conoutput circuit of the amplifier. i

The solenoid coils 35, 42 and 43 associated, respectively, with the vibratory members 13, 14 and 15, are each connected across a battery 44, through keys or switches 45, 46 and-4'7, respectively. Upon depression of any one of the keys to complete the circuit, the associated solenoid coil becomes excited to cause the corresponding vibratory member to be struck and set into vibration, thereby changing the flux distribution in the air-gap to induce a corresponding voltage wave in the pick-up coil. The note, corresponding to the period of vibration of this member, is then sounded from the loudspeakers 41.

WhileI have shown but three of the units, 10, 11, and 12, it is proposed to mount any desired number of these units in row formation, as shown in Fig. 1, the supporting members 21 and 9 being common to all. As before, the pick-up coils would be connected in series, parallel, or series-parallel, with the input circuit of the amplifier, and the respective solenoid coils would be connected in the same manner as coils 35, 42

and 43 in Fig. 3, a separate key or switch being supplied for each, and arranged with the others in the form of a keyboard for convenient operation.

While but one embodiment of my invention has been disclosed, it will be understood that various changes might be made, such as in the size, shape and arrangement of the various parts, without departing from the spirit of my invention or the scope of the claims.

I claim as my invention:

1. In pick-up apparatus of the character described, a plurality of pick-up units arranged in row formation and spaced from each-other, each of said units comprising complementary pole elements having pole portions, a member of nonmagnetic material common to said units and to which the complementary pole elements of each unit are secured with the respective pole portions held in spaced relation to provide air gaps, said member provided with openings opposite to the respective air gaps, vibratory members associated respectively with said units and. extending freely through said openings and said air gaps, and means supporting said vibratory members in fixed position for vibration free from said pole portions and the edges of said openings.

2. In an electrical pick-up device,-complementary pole elements having pole portions and supported with said portions in spaced relation to provide an air gap, an elongated vibratory member having an end portion disposed between said elements and extendingthrough said gap, and

means secured to one of said elements and hold respective air gaps, vibratory members associatedrespectively with said units and extending freely through said openings and said air gaps, and means secured to one of said pole elements of each unit for supporting said vibratory members in fixed position for vibrationfree from said pole portions and the edges of said openings.

4. In an electrical pick-up device, complementary pole elements having pole portions and supported .with said portions in spaced relation to provide an air gap, an elongated vibratory member having an end portion disposed between said elements and extending through said gap, a sub-- stantially L-shape support secured to one of said elements, and means clamping the tip of said end portion to said support to hold said member in fixed position for free vibratory movement from said tip.

5. In an electrical pick-up device, complementary pole elements supported in spaced relation to provide an air gap, an elongated vibratory member having an end portion disposed between said elements and extending through said gap, a sup- 3 port secured to one of said elements, and means clamping the tip of said end portion to said support to hold said member in fixed position for free vibratory movement from said tip.

6. In an electrical pick-up device, complementary pole elements supported in spaced relation to provide an air gap, an elongated vibratory member having an end portion disposed between said elements and extending througl said gap, a pick-up coil disposed between said elements and having a central opening through which said end portion of said member extends, and a support secured to one of said elements and holding said member for free vibratory movement from said support to the free end of said member.

CARROLL D. KENTNER.

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