US2492235A - Wave-signal translating apparatus chassis - Google Patents

Description

Dec. 27, 1949 D. H MITCHELL WAVE-SIGNAL TRANSLATING APPARATUS CHASSIS 3 Sheets-Sheet 1 Filed May 30, 1945 INVENTOR. DONALD H. MITCHELL E l i l L ATTORNEYS Dec. 27, 1949 D. H. MITCHELL 2,492,235

WAVE-SIGNAL TRANSLATING APPARATUS CHASSIS Filed May 30, 1945 3 Sheets-Sheet 2 mmmwzmc zoo n IVENTOR. DONALD H. MITCHELL ATTORNEY5 D. H. MITCHELL WAVE-SIGNAL TRANSLATING APPARATUS CHASSIS Filed May 30, 1945 Dec. 27, 1949 3 Sheets-Sheet 3 04 on C5 m INVI'ZN TOR.

D ONALD H. MITCHELL WWW ATTORNEYS Patented Dec. 27, 1949 v WAVE-SIGNAL TRANSLATING APPARATUS CHAS SIS Donald H. Mitchell, Chicago, Ill., assignor to Motorola, Inc., a corporation of Illinois Application May 30, 1945, Serial No. 596,783

2 Claims. (Cl. 173328) This invention relates to wave-signal translating apparatus chassis which is substantially free from bonded circuit connections and, while it is of general application, it is particularly suitable for embodiment in low-cost radio broadcast re ceivers adapted to be manufactured in large volume.-

It is well known that one of the principal cost factors of a radio broadcast receiver is the labor cost in assembling the extremely largenumber of circuit elements in their appropriate places and in making bonded connections to and between such elements, usually by soldering. Numerous attempts have heretofore been made toward the design of a radio broadcast receiver in which all of the parts would be completely preformed and would have connection provisions such that a mere assembly of the several elements on the supporting chassis would. complete the necessary connections without requiring any permanent bonding or soldering of auxiliary connectors to complete the circuit; that is a solderless receiver substantially free from bonded connections. However none of the arrangements so far proposed has met with commercial success usually because of one or more of the following factors: (1) The fabrication process was too complicated or too costly, or both, for practical use; (2) there was no practicable way for procuring simple circuit cross-over connections; and (3) certain of the circuit connections were impermanent and'became noisy in operation.

It is an object of the invention, therefore, to provide a new and improved wave-signal translating apparatus chassis substantially free from bonded circuit connections which is effective to overcome one or more of the above-mentioned disadvantages and limitations on such apparatus heretofore proposed.

It is another object of the invention to provide a new and improved wave-signal translating ap.. paratus chassis substantially free from bonded circuit connections which is relatively simple and inexpensive to fabricate and at the same time is rugged in construction.

It is another object of the invention to provide a new and improved wave-signal translating apparatus chassis of the type described incorporating simple circuit cross-over provisions.

It is another object of the invention to provide a new and improved wave-signal translating apparatus chassis of the type described in which all of the circuit connections are permanent and are quiet in operation.

In accordance with the invention, a wavesignal translating apparatus chassis substantially free from bonded circuit connections comprises a pattern sheet of insulation material having a plurality of prearranged group of apertures adapted to receive plug-in devices such as vacuum tubes, circuit-element assemblies, and the like. The chassis also includes a plurality of preformed circuit connectors disposed on the sheet, each including terminal elements disposed to be received in certain of the apertures of the sheet and to engage contact elements of predetermined ones of the devices and constituting substantially the sole connections between the devices, and means for securing the connectors in place on the sheet.

Further in accordance with the invention, the method of fabricating a wave-signal translating apparatus chassis of the type described comprises the step of perforating a sheet of insulation material to form a plurality of prearranged groups of apertures adapted to receive plug-in devices, such as vacuum tubes, circuit element assemblies, and the like. The method also includes the steps of preforming a plurality of circuit connectors with terminal elements and constituting substantially the sole connections between the devices, disposing the connectors on the sheet with their terminal elements received in certain of the apertures thereof, and securing the connectors in placeon the sheet.

Further in accordance with the invention, in a wave-signal translating apparatus chassis of the type described, there is provided a cross-over unit comprising a pattern sheet of insulation material, a plurality of preformed circuit connectors disposed on the sheet, such sheet being formed with a non-linear aperture therein defining a tongue of such sheet. A first of the preformed connectors has an offset portion proportioned to underlie such tongue while the second of the preformed connectors is disposed to overlie the tongue and to extend approximately normal to the first connector.

Further in accordance with the invention, in a wave-signal translating apparatus chassis of the type described there is included an arrangement for connecting an individual circuit element to the chassis comprising a pair of spaced apertures in the sheet, the apertures being disposed to register with two predetermined connectors and the connectors including provisions registering with the apertures for frictionally engaging circuit element connectors inserted therethrough.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken accompanying drawings pointed out in the appended in connection with the while its scope will be claims.

Refering now to the drawings, Fig. 1 is a schematic physical layout of a wave-signal translating apparatus chassis embodying the invention and utilized in a five-tube A, C.-D. C. radio broad cast receiver; Fig. 2 is a fragmentary perspective view of a portion of the chassis of Fig. l illustrating a circuit cross-over unit thereof; Fig. 3 is a detailed perspective view of an arrangement for connecting a circuit element such as a condenser into the chassis of Fig. 1; Fig. 4 is a view in elevation of a complete radio broadcast receiver embodying the chassis of the invention; while Fig. 5 is a schematic circuit diagram of a radio broadcast receiver corresponding to the physical layout of Fig. 1.

Referring now to Fig. 1 of the drawings, there is represented a schematic physical layout of a wave-signal translating apparatus chassis embodying the invention and substantially free from bonded connections. Specifically, the chassis represented is that of a five-tube A. C.D. C. broadcast receiver, although it will be understood that the invention is equally applicable to chassis of other wave-signal translating apparatus or to sub-assemblies or sub-chassis thereof, and the term chassis" as used herein and in the appended claims is intended to refer to any of such chassis, sub-chassis or subassembly.

The chassis of Fig. 1 comprises a pattern sheet ll of insulation material, such as a thermoplastic or thermosetting resin, having a plurality of prearranged groups of apertures ll-l8, inc. Each of these groups of apertures is adapted to receive a plug-in device; for example, the groups II, I I, II, II and I! are adapted to receive respectively a type 12SA7 oscillator-modulator tube, a type 128K! intermediate-frequency amplifier tube, a type 12SQ7 detector and first audio amplifier, a type 5016 beam-power audio-frequency ampliher, and a type 3525 rectifier, while the groups I! and II are adapted to receive intermediatefrequency selectors l9 and 20, respectively, and the group I8 is adapted to receive the local oscillator coil assembly 2|.

The chassis also includes a plurality of preformed strip-like circuit connectors, such as connectors 22-29, inc., comprising interconnections for the plug-in devices and the connectors and II comprising the +3 and B power supply buses, respectively. There are also a group of similar preformed connectors, such as the connectors 32-38. inc., for making connection between the several plug-in devices and the external circuits of the chassis. All of the connectors 22-", inc., described are top side of the pattern sheet ll, as viewed in Fig. 1, while there is also provided a preformed connector 3.9 disposed on the opposite side of the pattern sheet Ill and constituting the ground or reference potential bus of the chassis.

As shown more clearly in Fig. 2, each of the connectors, such as connectors I0 and II. includes one or more terminal elements. such as the terminal elements Ina and Ila, disposed to be received in certain of the apertures of the pattern sheet l0: in the case of the terminal elements Illa and Ila, to engage two of the apertures of the group I8 into which the oscillator coil assembly is to be plugged. As shown in Fig. 2, each of the terminal elements Illa, Ila comprises an elongated resilient contact clip exinc., and the condensers tending from its respective preformed connector and through its respective aperture in the pattern sheet ill. Preferably, the preformed connectors of the type described constitute substantially the sole connections or the entire connections between the several plug-in devices, such as the vacuum tubes described and the plug-in units is, 20 and ii, and to all external circuits to the chassis.

The chassis of Fig. 1 also includes a plurality of circuit cross-over units or arrangements for the connectors. These may be identified as the circuit cross-overs I2I8a, inc. Each of these cross-over units may be either single or double, by way of example the double cross-over I2 being represented in detail in Fig. 2. As shown in this figure, the cross-over I2 comprises a U-shaped aperture I2a punched or otherwise formed in the pattern sheet Hi and a first preformed connector, for example the B bus 3|, having an oiiset portion lla proportioned and disposed to underlie the tongue I2b between the arms of the U-shaped aperture In. The cross-over connectors In and II are disposed to overlie the tongue I2b and to extend approximately parallel thereto and approximately normal to the connector II. In this fashion, it is seen that the cross-over connectors II, It and II are completely insulated from each other and at the same time permanently retained out of contact with each other.

The chassis of Fig. 1 also includes a plurality of arrangements for connecting individual circuit elements to the chassis, such as resistors Ri-Ra. C1-C1, inc. For example, one such arrangement is shown in Fig. 3 illustrating the connection of the condenser C1 to the preformed connectors II and II. As illustrated in Fig. 3, the pattern sheet III is provided with a pair of llb, respectively, of the condenser Ca. For example, the connector II is formed with a small diamond-shaped aperture 3Ia having a pair of opposed peripheral fingers lIb. The connector elements are preferably of resilient material such as Phosphor bronze and the fingers, such as the fingers III), are offset from the plane of the connector so that they resiliently grip the circuit element connector 50b inserted through the apertures Ma and Ilb. This arrangement for connecting individual circuit elements merely by inserting or plugging them into appropriately spaced apertures in the several connectors is the manner of connection of the resistors R1-Ra, inc., and the condensers are It has been found that, with the construction illustrated, a permanent and quiet electrical connection is established between the circuit element connectors, such as the connectors "a, "b of condenser Ca, and the preformed chassis connectors and that this engagement is sufficiently strong that if it is attempted to remove the circuit elements, such as the condenser C1, the connectors "a, no may be torn from the circuit element or broken or, in some cases, the connection with the preformed chassis connectors permanently deformed.

The chassis of Fig. 1 also incorporates means for securing the several preformed circuit connectors 22-38, inc., in place on the pattern sheet C1-C1, inc., and the resistors R1-Rs, inc.

ner. The-sheets II and II are. secured together by screws, bolts, rivets, or the like, not shown.

The chassis of Fig. 1 is also adapted tobe connected to other elements of a radio broadcast receiver not forming a part of .the chassis per se. For example, the circuit connectors 32 and 34 are provided with terminals 32a and Ne, respectively, adapted to be connected to an external loop or antenna ground circuit. Similarly, the connectors 31 and II are provided with terminals 31a and Ila, respectively, which are adapted to be bridged by the back cover of the receiver carrying the loop, as described hereinafter, in order to open the power circuit to the chassis when the cover is removed and the various circuit elements of high potential are exposed. Further there is provided a separate volume control unit 82 having a conventional flexible connector no to the B bus ll. Also the receiver includes a sound reproducer or loud speaker I having an operating mechanism a which is connected to preformed connectors 54 and I8 constituting additional ground connectors and disposed on the opposite side of the pattern sheet 5| The speaker operating mechanism 53a is also provided with an external connection plug 53b having the connection prongs indicated as SP, 8+8 and SF andadapted to be connected to a conventional socket 530 having connections to points correspondingly identified on the chassis. The receiver is also provided with an electrolytic filter condenser Cs connected by conventional leads 56, 51 and 58 to the circuit connectors 16,

30 and 3|, respectively. Power for the receiver chassis is derived from an ordinary commercial power circuit by means of a removable plug 59 having leads 5! and Si connected to the bus connector 3| and to the connector 38, respectively.

In the fabrication of the wave-signal translating apparatus chassis of Fig. 1 described above, the pattern sheet iii of insulation material is perforated with registering groups of apertures ll-ll, inc., for the plug-in vacuum tubes and selector and oscillator-coil assemblies and with a plurality of pairs-of spaced apertures, such as the apertures 49a, 49b, for receiving the indi vidual circuit elements such as the condensers The sheet Si is also perforated with groups and pairs of apertures registering with those of pattern sheet it, one such aperture Sla being shown in Fig. 3. The pattern sheet It is also punched or stamped to provide a plurality of U-shaped apertures, such as the aperture 42a, to permit the formation of the cross-over units 424, inc.

The chassis circuit connectors, such as the connectors 2248, inc., are then stamped or otherwise formed from strip or sheet material, preferably of a resilient spring metal such as Phosphor bronze. Portions of the preformed connectors are formed into elongated resilient contact clips, such as the clips a, tin of Fig. 2, extending therefrom substantially normal to the plane of groups of apertures "-48, inc. In predetermined .6 to engage appropriateones ofthe ones cfztbe ,chcuit connectors 21-", inc., to

which individill circuit elements are to be attached, there are formed in pairs provisions for frictionally engaging the individual circuit element connectors when inserted through the pairs of apertures formed in the sheets ll andliregistering therewith. The frictional engaging provisions may be of the form illustrated in Fig. 3 and described. above. Theconnectors I240, inc., are thereupon disposed on one side of the pattern sheet II with their terminal elements or clips, such as the clips or, a, received in and extending through theircorresponding apertures inthe sheet II. The preformed ground connector II is disposed on the opposite side of the pattern sheet .IO and secured thereto in any suitable fashion while the ground connectors l4 and. II are disposed on the inner side of the sheet II and secured thereto.

Each of the U-shaped apertures, such as the apertures "a, is located at one of the circuit cross-over points of two of the preformed connectors 22-, inc., to form the cross-over units 4248a, inc. To this end, such of the circuit connectors as are involved in the circuit cross-over have a portion thereof offset, such as the offset portion Ila (Fig. 2) of connector fl, to underlie the tongue of the associated aperture in the sheet II, while the crossing connector or connectors are disposed and arranged to overlie the tongue and extend approximately normal to the underlying connector.

Thereupon the several connectors are secured in place. This may be eflfected in any convenient manner but preferably and as illustrated by juxtaposing the pattern sheet ii upon the pattern sheet it with their apertures in register and securing them together by any suitable means such as screws, rivets, or the like, (not shown) to retain the circuit connectors in place.

In Fig. 4 is illustrated a view in elevation, partly in section, of a complete radio broadcast receiver incorporating the chassis apparatus of the invention. This receiver comprises an enclosing cabinet or housing ill with the chassis comprising the pattern sheets i0 and Si mounted vertically therein and extending substantially across the inside of the cabinet. The various vacuum tubes, such as the tube 8i, and the various coil assemblies, such as the oscillator assembly 2|, are plugged in to the chassis of the set and extend horizontally therefrom. Also secured to the chassis by screws, bolts, rivets, or the like, is the volume control unit 52 provided with a manually operable adjusting knob 52a mounted on a shaft 52b extending through the front of the cabinet. The loud speaker 53 is also secured to the chassis sheets and SI by means of screws or bolts "b which also engage the ground or reference potential buses 54, it, thereby grounding the unit. The tuning condensers are likewise secured to and supported from the chassis sheets l0 and ii and are provided with a tuning knob 62 secured to a shaft 82a extending through the front of the cabinet and connected to adjust the tuning condensers through gearing 2b. The back of the cabinet It is closed by a panel member ll spaced from the chassis sheets l0 and Si by suitable posts It having pins "a engaging the terminal contacts 32a and "a. A receiving loop antenna 05 is mounted on the back plate It, while this plate also carries a the connectors and at predetermined spaced 1 bridging contact (not shown) for the power supnon-linear slot therein of, a first one 01' said --set portion 01 such a,saa,ass

is an entirely conventional five-tube A (1-D. C. I

superheterodyne receiver, the operation of is well understood in the art, it is believed that an explanation of such operation is unnecessary herein. While the invention has been illustrated and described as applied to a conventional fivetube A. (1-D. C. superheterodvne-broadcast receiver, it is to be understood that this embodiment is purely illustrative and that the chassis oi the invention is applicable generally to chassis of wave-signal translating apparatus, including receivers and transmitters, comprising either the complete chassis of the wave-signal translating apparatus or a sub-chassis or sub-assembly thereof.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

What is claimed as new is:

1. A chassis for supporting and interconnecting electrical devices oi the plug-in type, said chassis comprising a fiat sheet of insulating which material having apertures arranged to conform with a predetermined pattern for receiving the plug portions of the electrical devices, a plurality of rigid strip conductors respectively extending between predetermined ones of said apertures, and holding means for securing said conductors to said insulating sheet, said conductors having integral spring contact clips respectively positioned in certain of said apertures in said sheet for directly receiving the plug portions and atiording unbonded electrical connections therewith, said insulating sheet having at least one defining a tongue thereconductors having an 01!- configuration to be transversely lnsertable in said slot to underlie said tongue, another one 01 said conductors being disposed to overlie said tongue and extend approximately normal to said first conductor, whereby said tongue extends between such conductors to insulate them one from the other, said spring contact clips and said offset portion or said conlog electrical devices first insulating slot said insulating sheet. 7

2. A chassis for supporting and interconnectci. the plug-in ype. said chassis comprising a first fiat sheet of insulating material having apertures arranged to conform with a predetermined pattern for receiving the plug portions or all said devices, a plurality of rigid strip conductors respectively extending between predetermined ones of said apertures, and a second insulating sheet secured to the first insulating sheet with said conductors of such configuration to be transversely insertable in said slots to underlie said tongues. said spring contact clips and said ofiset portions of sheet, being respectively disposed to overlie said tongues to provide insulated cross-overs between said conductors.

DONALD E. CHELL.

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

UNITED s'rs'rns PATENTS Number Name lite 878,949 Hanson Feb. 11, 1908 1,691,877 Alden Nov. 13, 1928 1,718,993 Wermine July 2, 1929 1,755,934 Reyner Apr. 22, 1930 1,892,148 Harshberger Dec. 27, 1932 1,939,130 Dec. 12, 1933 1,984,998 Boreny Dec 18, 1934 1,997,270 Titus Apr. 9, 1935 2,019,625 O'Brien Nov. 5, 1935 2,068,876 Carpenter Jan. 5, 1937 2,151,433 Mac'rwigaan Mar. 21, 1839 2,268,619 Reid Jan. 8, 1942 2,309,971 McLarn Feb. 2, 1943 1,364,846 Hartman Dec. 12, 1944 2,390,706 Hearon Dec. 11, 1945

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