US3550459A - Pushbutton tuner - Google Patents

Description

Dec. 29, 1970 T R ET AL 3,550,459

PUSHBUTTON TUNER Filed Jan. 22, 1969 5 Sheets-Sheet 1 FIG. 4.

INVENTORS THOMAS E GOSNELL ATTORNEY FER/VA/VD FPELLET/ER' D66. 29, 1970 F, F PELLETlER ET AL 3,550,459

PUSHBUTTON TUNER Filed Jan. 22: 1969 3 Sheets-Sheet 2 FIG. 2.

FER/VA/VD F PELLET/ER THOMAS F GOSNEL L INVENTORS BY w.

ATTORNEY Dec. 29, 1970 F, PELLET|ER ET AL 3,550,459

PUSHBUTTON TUNER Filed Jan. 22, 1969 3 Sheets-Sheet 3 INVENTORS FER/VA/VD F PFELLET/ER [2, BY THO/14A S 4 [014.13% ATTORNEY United States Patent 3,550,459 PUSHBUTTON TUNER Fernand F. Pelletier and Thomas F. Gosnell, Baltimore,

Md., assignors to The Bendix Corporation, a corporation of Delaware Filed Jan. 22, 1969, Ser. No. 793,120 Int. Cl. F16h 35/18 US. Cl. 74-1033 6 Claims ABSTRACT OF THE DISCLOSURE A pushbutton t-uner useful with radio receivers used in mobile vehicles such as automobiles having stringent space requirements is described. The inventive pushbutton mechanism permits a substantial decrease in the size of the tuner mechanism. This is accomplished by using the pushbutton as an extension of the slide bar which tunes the radio. The pushbutton also serves as a guide member for the slide resulting in a reduction of the number of parts required for the tuner mechanism.

As the safety and entertainment requirements for mobile vehicles such as automobiles increases the space shortage for incorporating such instruments into the vehicles becomes more critical annually. As an example, whereas initially automobiles contained only an AM radio as an entertainment element, today automobiles frequently include AM and FM radio reception as well as tape recorders. The room available in the vehicles for such elements has remained substantially constant and therefore the elements themselves must be reduced in size. One perplexing problem which exists relates to the reduction of the mechanical section of the pushbutton tuner which is used to tune a radio receiver in such vehicles.

The pushbutton tuners presently available can be used to tune the radio either by the turning of a knob or the pushing of a particular button representing a particular station. In such tuners, in order to set the pushbutton at a particular station the radio is tuned to that station by use of a rotating knob located on the vehicle dashboard. Rotation of the knob electrically tunes the tank circuit of the radio and simultaneously rotates a treadle bar which is composed of two parallel rods joined together to rotate about an axis midway between the two rods. As the radio is tuned from the highest to the lowest frequency the treadle bar rotates approximately 60. A series of slide bars are arranged perpendicular to the axis of the treadle bar and are located such that they pass between the rods thereof. The slide bars are actuated by pushing the pushbuttons located on the face of the radio in the vehicle dashboard. A rotatable cam is mounted on each of the slide bars, the cam being configured such that it interferes with the rods composing the treadle bar. Also located on the slide member is a detent which is used to inhibit the rotation of the cam member.

In order to set a particular pushbutton to repeatedly select a particular station, the receiver is tuned to that station by use of the tuning knob located on the face of the radio. This causes the treadle bar to assume a particular angular position. The pushbutton is set by pulling it outwardly thereby releasing the detent allowing the cam member to rotate more freely than the treadle bar. The pushbutton is then pressed forward causing the cam member to engage the rod members of the treadle bar. This causes the cam member to assume the same angular position as the treadle bar. As the pushbutton is continued to be pushed forwardly the detent engages the cam member locking it into that particular angular position. After the receiver is det-uned from that particular station and the knob is pushed in an attempt to select that station, the cam member moves forward engaging the rods of the 3,559,459 Patented Dec. 29, 1970 ice treadle bar causing the treadle bar to assume the same angular position as the cam member.

These two systems have long been used in the radio art and have been found to be quite satisfactory for their intended usage. However, they do suffer the disadvantage of requiring a substantial amount of room for the mechanical mechanism. This is so because the pushbutton itself is useful only in engaging and disengaging the detent and in actuating the slide bar. The guide member for the slide bar is a separate element as is the biasing member for the detent.

It is therefore an object of this. invention to provide a pushbutton tuner which is substantially smaller than presently available tuners useful for the same purpose.

It is another object of this invention to provide such a tuner which has a pushbutton construction which enables the pushbutton to serve as an extension of the actuating slide resulting in a reduction of the physical size of the tuner.

It is another object of this invention to provide such a tuner wherein the pushbutton also serves as a guide for the slide member.

It is another object of this invention to provide such a tuner wherein the pushbutton serves to bias a detent which is included as a functional element of the tuner.

It is another object of this invention to provide such a tuner including a sloped surface on the slide member for engaging a guide bar thereby assuring repeatability of station selections.

Further objects, features and advantages of the invention will become apparent from the following description and claims when read in view of the accompanying drawings, wherein numbers indicate like parts and in which:

FIG. 1 is a partially sectioned pictorial view of a preferred embodiment of the instant invention.

FIG. 2 is a sectional view taken along line II-II of FIG. 1.

FIG. 3 is a sectional view taken along line IIIIII of FIG. 1.

FIG. 4 is a sectional view showing the elements in their position when the pushbutton is depressed and also showing features which assure the repeatability of frequency selection.

In FIG. 1 the inventive tuner is indicated generally by reference numeral 10. The tuner includes a treadle bar comprised of two rods 11 and 12 mounted on opposite sides of a disc 13. The disc 13 and rods 11 and 12 therefore rotate as a unit (hereinafter referred to as a treadle bar) about an axis 14. It should be noted that rods 11 and 12 are also mounted on another disc at the other end thereof to maintain their parallel relationship. The axis 14 of disc 13 is connected to the tuning knob located on the vehicle dashboard by use of a tuning mechanism well known in the art and therefore not fully described therein. Such a tuning mechanism is fully shown in US. Pat. No. 2,863,043 by O. Schmidt et al.

Tuning of the radio effects rotation of the treadle bar about axis 14 approximately 30 on each side of the vertical position. A pushbutton 16 is mounted on the face plate 17 of the radio receiver. Face plate 17 includes a plurality of guide holes 18 for receiving the pushbutton 16. The back plate 19 of the tuning mechanism is held in a parallel position with respect to face plate 18 by slide members 21. Back plate 19 includes a plurality of guide slots 22. A slide member 23 is supported between guide slots 22 and pushbutton 16. A spring 24 biases slide 23 outwardly toward pushbutton 16. A cam 26, having two contact surfaces 27 and 28, is rotatably mounted on slide 23 by means of a rivet 29 or some other convenient means. A detent 31 which extends .into pushbutton 16 acts against cam 26 to inhibit rotation thereof when in the locked position.

A clear picture of the inventive tuner can be obtained by viewing FIG. 2 which shows a sectional view of the inventive tuner in the unactuated position. The slide member 23 includes a shank portion 37, the extreme end 38 of which is in physical contact with the inside surface of pushbutton 16. Slide 23 therefore extends from pushbutton 16 through guide slot 22 such that the end of slide 23 extends beyond the back plate 19. Slide 23 is biased into pushbutton 16 by spring 24 which acts against surfaces 34 and 36 of the slide member 23. Rejection of the slide member 23 from pushbutton 16 is prevented by ex tensions 32 and 33 of slide 23, which act against the inside of face plate 17. Contact surfaces 27 and 28 of cam 26 extend radially from the rotational axis of cam 26 a distance sufficient to insure contact between the surfaces 27 and 28 and rods 11 and 12.

FIG. 3 shows that the internal surface of pushbutton 16 is constructed to include a slot 39 which is configured similarly to the cross-sectional configuration of slide 23. One side of the outside of slot 39 is configured to include a surface which is parallel to slot 39 for a portion 41 of its length and a sloped portion 42 for the remainder of its length. Detent 31 is spaced away from slide 23 by use of a spacer 43 and is held in place by a rivet 44 or some other connecting element. Detent 31 is therefore free to rock slightly about the axis 46 running through its mounting point and perpendicular to the longitudinal axis of slide 23. With detent 31 in the position shown in FIG. 3 the end 47 of detent 31 presses tightly against cam 26, thereby greatly inhibiting rotation of said cam member.

Operation of the invention can best be understood by viewing FIGS. 2 and 3. Assume that the radio is tuned to a station such that the treadle bar has caused rods 11 and 12 to assume the positions shown as 11a and 12a, respectively, and it is desired to tune the radio to a station in which the treadle bar would assume the position shown at 11 and 12. In order to accomplish this the cam 26 would be in the angular position shown in FIG. 2. In order to tune the radio to the desired station pushbutton 16 is depressed against the action of spring 24. As the slide moves to the right as shown in the figures, surface 28 of cam 26 will first engage rod 11 as it lies in the position 11a. Because cam 26 is inhibited from rotating due to the action of detent 31 the treadle bar will rotate causing rod 12 to move from its position 12a toward the position 12. When both rods 11 and 12 are in contact with surfaces 28 and 27, respectively, the radio is tuned to the desired station and no further rotation of either the treadle bar or cam 26 is possible. When the pushbutton 16 is released spring 24 returns slide 23 to its neutral position permitting tuning of the radio by either another pushbutton or the tuning knob on the face of the radio.

The manner of setting cam 26 in a position assuring the repeatability of the selection of the station represented by the positions 11a and 12a can be best understood by first assuming that the treadle bar is in a position such that the rods 11 and 12 are in the positions 11a and 12a. In order to set the cam to this angular position pushbutton 16 is pulled outwardly, to the left as shown in the figure. This causes detent 31 to move along surface 41 to the sloped portion 42. As detent 31 moves along sloped portion 42 the biasing force applied to cam 26 is substantially reduced. This permits a substantially more free rotation of cam 26. Consequently, after the outward most position of pushbutton 16 is reached and the pushbutton 16 is pushed inwardly, slide 23 will slide within slot 22 of back plate 19 against spring 24. This sliding action continues until surface 28 of cam 26 contacts bar 11 in the position 11a. When contact between surface 28 and rod 11 is made cam 26 begins to rotate counterclockwise. The counterclockwise rotation continues until surface 27 of cam 26 contacts rod 12 in the position 12a. At the instant this contact is made rotation of cam 26 or of the treadle bar 13 can no longer be realized and consequently the further pushing force on pushbutton 16 causes detent 31 to slide up sloped surface 42 until the rear end 48 of detent 31 contacts tl1 e.back of .pushbutton 16, .or untilextensions 32 and 33 of slide 23 prevent further insertion of slide 23 into pushbutton 16. When pushbutton 16 is released it is biased into its neutral position by spring 24 and the tuner is tuned to the desired station.

Repeatability in selecting the desired station is assured because detent 31 has returned to the position shown in FIG. 3 and consequently, rotation of cam 26 is substantially inhibited and therefore the treadle bar rotates more freely than cam 23. Consequently, any time selection of the station is desired it can be achieved simply by depres sing pushbutton 16 causing the surfaces 27 and 28 of cam 26 to contact the bars 11 and 12 of treadle bar 13, thereby causing rods 11 and 12 to assumethe angular position of cam 26 set in the setting process.

It should be noted that although the tuning mechanism shown in the previous figures is quite satisfactory for'many purposes one slight difiiculty can arise if rather accurate tuning is desired. This difficulty arises from the fact that the slide 23 is free to slide through guide slot 22, thereby permitting a small'amount of vertical play of slide 23 within the slot. If accurate tuning is required this play may permit a sufficient difference in the angular setting of treadle bar 13 to result in ineffectual tuning. This difii culty can be easily overcome by adding the modifications shown in FIG. 4 to the slide 23 and cam 26.

FIG. 4 shows the tuner mechanism in the position it asumes when the pushbutton 16 is fully depresed. In order to assure repeatability of tuning it is necessary that the center 51 of cam 26 lies on the line connecting centers 49 and 50 of rods 11 and 12, respectively. This is accomplished by dimensioning cam 26 such that the contact surfaces 27 and 28 contact rods 11 and 12 at a point which is offset from center 51 a distance equal to the radius of said rods. The contact surfaces 27 and 28 are therefore offset from the rotational axis 51 of cam 26 by an amount equal to this radius. By so dimensioning cam 26 and contact surfaces 27 and 28 the rotational axis 51 will always fall along the line connecting centers 48 and 49 of rods 11 and 12, respectively, irrespective of the angular position of the cam and the treadle bar 13. I

The linear alignment of slide 23 with respect to the axis of the tuning mechanism can be guaranteed by assuring that the bottom surface of slide 23 contacts the bottom surface of slot 22. This can be accomplished by dimensioning the forward portion 52 to be smallerthan the width of slot 22. The rearwardmost portion of slide 23 is dimensioned to be larger than the vertical dimension of slot 22. The linear sloped portion 53 connects the wide and narrow portions of slide 23. In this manner the sloped portion of slide 23 will always int'erferewith the top portion of slot 22, thereby guaranteeing that the bottom of slide 23 rests on the bottom of slot 22 when the pushbutton 16 is fully depressed.

An alternative method of assuring accurate alignment of slide 23 is illustrated in FIG. 2. By sloping the outer surface 54 of pushbutton 16 downwardly and outwardly, a slight turning force will be applied to the pushbutton when it is depressed. Pushbutton 16 will therefore rotate counterclockwise within guide 18. Rotation of pushbutton 16 will result-in a slight rotation of slide 23 thereby causing the upper surface of slide 23 to interfere with the top of slot 22. The possibility of binding between slide 23 and the top of slot 22 can be eliminated by slightly rounding or leveling corner 55 of slot 22.

Although this invention has been described with respect to a particular embodiment thereof, it is not to be so limited, as changes and modifications may be made therein which are within the spirit and scope of the invention as defined by the appended claims.

The. invention claimed is:

, 1. In a pushbutton tuner of the type having an axially movable actuating slide, a cam rotatably mounted on said actuating slide, and a treadle bar for effecting-the tuning action, said treadle bar including parallel longitudinal members arranged diametrically opposed about the axis of rotation of said treadle bar, said cam, including extended surfaces for contacting said longitudinal members whereby rotation of said treadle bar is effected by engagement of said cam with said treadle bar;

the improvement which comprises:

means within and integral with said pushbutton for slidably receiving said actuating slide, said means for receiving including a slot internally configured similarly to the cross-sectional configuration of said actuating slide, and externally configured to have a biasing portion and a slanted portion; and

detent means for inhibiting rotation of said cam when said pushbutton is in a frequency selecting position and permitting rotation of said cam when said pushbutton is extended into a frequency setting position, said detent means including a resilient member which engages said cam and said biasing portion of said receiving means when said pushbutton is in said frequency selecting position and engages said cam and said slanted portion of said receiving means when said pushbutton is in said frequency setting position.

2. The tuner of claim 1 wherein said tuner further includes a support plate having guide means for receiving the free end of said actuating slide, said guide means having first and second surfaces; the major portion of said actuating slide being incapable of entering said guide means and said free end being angularly reduced over a portion thereof to enable said free end to enter said guide means, said angularly reduced portion contacting said first surface when said free end enters said guide means whereby said actuating slide is precisely positioned by said guide means.

3. The tuner of claim 2 wherein said extended surfaces are offset from the axis of rotation of said cam by a distance equal to one-half the cross-sectional dimension of said longitudinal members 4. The tuner of claim 1 wherein said tuner further includes a guide member having an orifice therein for receiving said free end of said actuating slide; said actuating slide includes substantially parallel slides and a sloped portion at said free end, the dimension between said parallel sides exceeding the dimension of said orifice and the dimension at the end of said sloped portion being less than the dimension of said orifice; and wherein said treadle bar includes parallel positioned rods lying diametrically opposed about the axis of rotation of said treadle bar; and wherein said carn includes wings for contacting said rods and effecting rotation of said treadle bar.

5. The tuner of claim 4 wherein said wings are offset from the axis of rotation of said cam by a distance equal to the radius of said rods.

6. A tuner as recited in claim 1 further including a support plate having guide means for receiving the free end of said actuating slide, said guide means having first and second surfaces, and wherein said pushbutton includes a sloping face portion whereby pressure applied to said face portion produces a rotational motion of said pushbutton and said actuating slide, thereby forcing one surface of said actuating slide against said first surface of said guide means.

References Cited UNITED STATES PATENTS 2,424,845 7/ 1947 Plensler 74l0.33 3,403,564 10/1968 Ohashi 74--10 .33

FOREIGN PATENTS 742,939 1/1956 Great Britain 74l0.33

MILTON KAUFMAN, Primary Examnier US. or xn, 334-7

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