US2168984A - Construction and manufacture of radio receivers - Google Patents

Description

2 Sheets-Sheet l D. GRIMES Aug. 8, 1939 COESTRUCTION AND MANUFACTURE OF RADIO RECEIVERS Filed March 10, 1937 2 6 Z m r k C W) 2 m z 6 Z Z HHH". |H. U O B a M 8 o e 5 o f v Q 3 3 w v o o. g t v Aug. 8, 1939 D. GRIMES 2,168,984

CONSTRUCTION AND MANUFACTURE OF RADIO RECEIVERS Filed March 10, 1957 2 Sheets-Sheet 2 said shaft, and provides Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE CONSTRUCTION AND MANUFACTURE OF RADIO RECEIVERS David Grimes, Beverly,

Radio and Television N. 1., asslgnor to Philco Corporation, Philadelphia, Pa., a corporation of Delaware Application March, 10,

In Great Britain March 11,

8 Claims.

principal object of the invention is to provide a novel chassis structure and a novel structural arrangement of the parts or elements of a radio receiver, and to provide other specific features as set forth in detail hereinafter.

A more specific object of the invention is to provide a novel mounting for a unit including a tuning element having a control shaft, which mounting isolates the unit against extraneous vibrations, permits adjustment of the position of chimney-like structures at the sides of the unit, as fully described here inafter.

By the present invention, it is commercially practical in the manufacture of radio receivers to employ a plurality of units, each comprising certain elements arranged in predetermined relation to one another, and to arrange the units in predetermined relation to each other. In this manner, the units may be manufactured separately and may be tested individually, so that any defects that may occur are localized in the units and it is readily possible to locate and remedy such defects, thus eliminating the necessity of examining the entire receiver to locate such defects. Moreover, it is possible by the employment of units according to the present invention to manufacture various forms of each unit and, by the use of different combinations of the said forms, to manufacture different types of radio receivers. A large number of different types of receivers may thus be manufactured or built by manufacturing a relatively small number of different units and assembling the different units in various combinations.

The employment of units according to the present invention, and the predetermined design and assembly of the units, as above mentioned, results in other important advantages. For example, as will be described in detail hereinafter, the unit including the tuning element is nonmicrophonically and adjustably mounted and, furthermore, by the use of the invention the sensitive parts of the receiver are isolated thermally from the heat-generating parts or elements, and the other equally important advantages are obtained.

The invention will now be described ,in detail with reference to the accompanying drawings as 1937, Serial No. 130,202

applied to a conventional superheterodyne multiwave band receiver, but it will be understood that the invention is not thus limited but is applicable to any type of radio apparatus.

In the drawings:

Fig. 1 is a plan view of the radio receiver with in a cabinet;

Fig. 2 is a front view of Fig. 3 is a sectional line 33 of Fig. 1;

the vacuum tubes removed and before mounting the receiver; detail view taken along Fig. 4 is an exploded perspective view of a front mounting for the R. F. unit; and

Fig. 5 is a sectional detail view of the said mounting.

In accordance with the invention as disclosed in the drawings, a superheterodyne multi-band receiver may be constructed as follows:

The receiver is built in ments (transformer l, rectifier electrolytic filter condensers 3, audio output elements (power sockets 4). In receivers of this three units A, B and C. One unit A may comprise the power supply eletube socket 2, etc.) and the amplifier tube type, the field coil of the loud speaker may be used as a filter choke.

A second unit B may comprise the radio frequency portion of the receiver, which includes the R.

F. amplifier tube socket 5, electrolytic frequency amplifier portion of the receiver and the second detector, and may include the I. F.

amplifier tube socket H, the shielded I. F. coils I2, the second detector tube socket 13, etc.

The

units are assembled adjacent one another in the order named, with the second or R. F. unit B mounted between the other two units, as shown clearly in Fig. 1.

The outer unit A may comprise a base or supporting plate i4 having a depending flange [5 (see Fig. 2) at its outer flange l6 at its inner edge. outer unit C may comprise a edge and an upstanding Likewise, the other base or supporting platell having a depending flange l8 at its outer edge and an upstanding flange I!) at its inner edge. The two plates mounted in predetermined space parallel bars 20 and 2| which are similar and The plates and their dependinterchangeable.

and

relation on two ing flanges are attached to the bars by bolts 22 or the like, and the plates thus serve to fix the bars in position and, together serve as a chassis or foundation with the bars, framework for the receiver parts. The plates l6 and I! also I serve cooperatively to support the inner unit B.

This unit comprises an inverted box-like base or support 23 floatingly attached to the upstanding flanges i6 and I9 of the said plates and to a rear supporting plate 48 by means of resilient mounting members 24 and 25. Thus, unit B is floatingly mounted at three points and is held in spaced relation to the other units, as will be discussed in further detail later.

The radio frequency unit B, which contains the most sensitive elements of the receiver, is isolated against extraneous vibrations by virtue of its floating mounting, and microphonic action is thus prevented. This unit is also isolated thermally from the other two units, so that the frequency of the oscillator, which depends in part at least on the temperature of its tuned circuit parts, is substantially unaffected by heat from the power unit. The mounting of the R. F. unit B spaces the side walls of its base 23 from the flanges l6 and I9 of the outer units, so that vertical chimney structures forming air spaces 26 are formed by these cooperating walls and the flanges on each side of the R. F. unit B. These air spaces serve to isolate the units B and C from each other and from unit A and they also serve to prevent the heat dissipated from unit A from causing temperature rises of the sensitive parts of units B and C. As some of the elements of both the R. F. amplifier unit 13 and the I. F. amplifier unit C are thermally sensitive and prone to vary electrically with variations in temperature, it will be apparent that the particular mounting provided by the invention serves a very important function in that it prevents the transfer of heat from unit A to the units B and C.

It is also characteristic of the R. F. unit B provided by this invention that the coils and waveband switches are mounted at the bottom of the unit within the box-like support 23 and are, therefore, placed further sources of heat in unit A. Moreover, the walls provided by the supporting bases of the several units serve thermally to isolate the R. F. unit, particularly the coils and padding condensers thereof. It will be obvious that these walls, being heat conductive and heat reflecting, tend to carry the heat off or to radiate it so that the heat is prevented from getting to the sensitive parts, such as the coils, padding condensers, etc. Moreover, the chimney-like structures above mentioned provide drafts of cool air flowing upward through the spaces 26, thus providing ventilation and cooling the walls of the R. F. unit, as well as aiding in the dissipation of heat from the rectifier and A. F. output tubes. 7

The shaft 49 of the wave-band switches is removably held in place by means of screws and indexing mechanism 5| (see Fig. 2).

The tuning condenser assembly i9 is mounted directly over the coil-switch assembly and is provided with terminal plates 39, so that the leads from the coil-switch assembly may be brought up through openings in support 23 to the terminal plates. The tuning condenser assembly is mounted on front lugs 3| and rear support 32.

To prevent straining the condenser frame, with consequent variations in its electrical characteristics, due to slight misalignment between the two front supports 3| and the rear support 32, such as might obtain in practice, the rear of the condenser assembly is resiliently mounted. This specific mounting of the tuning condenser assembly forms the subject of the copending applicafrom and below the tion of Elmer 0. Thompson, Serial No. 129,968, filed March 9, 1937.

To permit alignment of the condenser shaft with respect to the front of the radio cabinet, the position of the rear of the R. F. unit 13 is 5 adjustable as to height, the front supports '24 permitting pivotal movement of the front of the unit, as will be more clearly understood from the subsequent description of the front mountings. Thus, the entire unit B may pivot to a small extent about the front resilient supports 2 which permits the position of the shafts 35 and 36, which carry the tuning controls and tuning dial, to be adjusted with respect to the chassis. As mentioned above, this central unit, which carries the tuning condenser, tuning control shaft and its associated control knobs, tuning dial, etc., should be fioatingly mounted to avoid microphonics and undesirable vibration of the electrical parts which are sensitive to mechanical disturbances. The commercial manufacture of such a floating mounting, however, requires broad tolerances in the mounting and makes it impossible to align exactly the tuning control shaft with the holes in the cabinet through which this tuning shaft extends. By my invention, however, I have provided a means by which the position of the tuning shaft is made adjustable and thus the inaccuracies incurred by the required broad tolerances are overcome. It will be understood that it is not necessary to have the entire unit,

adjustable, but my invention contemplates a tuning unit having a control shaft in which the front of the unit is pivotally mounted, and the rear of the unit is adjustably mounted so that the position of the tuning shaft may be adjusted to compensate for the variations which will occur in the resilient mounting.

As shown in Fig. 3, the supporting member 48 is secured to the rear bar 2|, and also to the flanges i6 and I9. Member 48 carries the resilient member 25. A screw 46 extends through member 25 and through a slot 53 in the rear wall of support 23 and threadedly engages an adjusting member 54. A sleeve 55 and metal washer 56 prevents the screw from compressing the member. 25, while the flange 51 on sleeve 55 also serves with member 54 to lock the parts in position. A look washer 58 is preferably employed between member 54 and the wall of support 23. It will be seen that the screw 46 may be variously positioned in slot 53 to efiect. the desired adjustment. It will be noted also that the unit B may be removed by simply removing screw 66.

In assembling the units, the R. F. unit B is readily mountable between the units A and C by virtue of the mounting provided. The flanges l6 and i9 are flared outward at their front portions, as shown at ti in Figs. 1 and 4, and these flared portions are provided with elongated openings 42 within which the resilient members 24 may seat. Each of these resilient members comprises a ring or washer of rubber or like material having a seating portion 43 and a flange 44, as shown in Fig. 4. Each said member is secured to the side ,wall of the box-like support 23 by means of a flared stud 45 (see Fig. 5). The seating portion is adapted to seat in the elongated opening with which it is associated. It will be seen that in mounting the unit B, the members 24 may be placed between the flared portions of flanges l5 and I9 and then drawn back into the openings in the closer portions of the flanges.

The. washers 24 and 25 have their critical 7 dimension, 1. e. the dimensions transversely of the axes of the washers, arranged so that they may be accurately defined by the mold in which the washers are formed, while the axial diare not critical are determined of material placed in the mold. This insures that the said critical dimensions will be accurate.

It will be seen that the unit A is made or built with the A. F. power output tube sockets 4 at the rear, and with the transformer l and rectifier tube socket 2 at the center, with the tube socket I mounted on top of the transformer, the electrolytic filter condensers 3 being at the front. The A. F. output tubes are one of the principal sources of heat in the receiver, and by positioning these tubes at the rear, the heat is dissipated most effectively, it being remembered that the back of a radio cabinet is usually open or well ventilated, whereas the front is closed. The power supply transformer and rectifier tube are also sources of a substantial amount of heat and hence they are positioned adjacent the output tubes. Moreover, the rectifier tube, which, in operation, is the hotter forms the subject of my copending application, Serial No. 129,935, filed March 9, 1937.

This particular rectifier and transformer construction is useful in itself in minimizing the temperature rise of this particular apparatus. In

said shaft. The invention also contemplates broadly the provision of chimney-like structures on opposite sides of the said unit.

From the above description, it will be seen that the invention provides novel features of construction which facilitate and simplify commercial manufacture of radio receivers and which greatly improve the operation of the receiver.

I claim:

i. In a radio receiver, a unit comprising a plurality of elements including a tuning element having a control shaft mounted on a common support or base, means for pivotally mounting the front of said support, said means comprising a pair of opposed pivotal mountings on opposite sides of said support, each of said mountings comprising wall with an elongated openresilient member carried by said support adapted to be drawn into said openings so as to seat therein, and means for adjustably mounting the rear of said support to permit variation of the position of said shaft.

2. In a radio receiver, a pair of interconnected spaced units forming a supporting structure, another unit disposed between said first-mentioned units, and means for floatingly and ad- Justably mounting said other unit in spaced relation with respect to said first-mentioned units, said means comprising a pair of front mountings, and a rear adjustable mounting carried by the supporting structure.

3. In a radio receiver, a pair of spaced walls, a unit having opposed side walls mounted between said spaced walls in spaced relation thereto, whereby chimney-like spaces are formed by the said walls on opposite sides of said unit, means for resiliently attaching the side walls of said unit to said spaced side walls, and means for resiliently mounting the rear of said unit.

4. In a radio receiver, a pair of spaced walls, a unit having opposed side walls mounted between said spaced walls in spaced relation thereto, whereby chimney-like spaces are formed by the said walls on opposite sides of said unit, means to said spaced side walls, and means for resiliently and adiustably mounting the rear of said unit.

5. In a radio receiver, a pair of interconnected spaced units having inner vertical walls spaced from one another, and another unit having opposed side walls mounted between said vertical walls in spaced relation thereto, whereby chimney-like spaces are formed by the said walls on opposite sides of said other unit.

6. In a radio receiver, a pair of interconnected spaced units having inner vertical walls spaced from one another, another unit having opposed side walls mounted between said vertical walls in spaced relation thereto,

I said other unit. of said unit to permit variation of the position of 7. In a radio receiver, a pair of interconnected spaced units having inner vertical walls spaced from one another, another unit having opposed side walls mounted between said vertical walls in spaced relation thereto, whereby chimney-like spaces are formed by the said walls on opposite sides of said other unit, means for resiliently attaching said side walls to said vertical walls, and means for resiliently and adjustably mountin: the rear of said other unit.

8. In a radio receiver, a pair of spaced walls having an open space therebetween, and a chassis unit having opposed side walls mounted between said spaced walls in spaced relation thereto, and providing unobstructed chimney-like passages between said first-mentioned walls and the walls of said unit on opposite sides of said unit, said passages creating drafts of cool air therethrough to cool and ventilate said unit.

DAVE) GRIMES.

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