GB2031675A - Keyboards for pre-set tuning - Google Patents

Abstract

In a keyboard for presetting tuning in e.g. an automobile radio a pivoted bracket 27 is mechanically connected to a tuning system of the radio for programming a memory plunger 14 of each key 10. Horizontal sections 33 (33', Fig. 2) of the bracket 27 are arranged over opposite faces of a fixed support plate 1 so as to engage with plungers 14 of two series of keys 10 one above the other. When a key is pulled outwardly a resilient lock 13 releases a plunger 14 of that key and enables a tuning knob 6 to adjust bracket 27 to the required station. On pressing in the key the plunger engages a horizontal section 33 of the bracket and is locked by 13 in this position. When that key is subsequently pressed a slide 21 declutches the bracket 27 from the tuning knob 6, the memory plunger 14 positions the bracket to the required position and a slidable latch 2 retains the key. <IMAGE>

Description

SPECIFICATION Improvements in or relating to keyboards for preselection of electromagnetic signals This invention relates to a keyboard for tuning preselection of electromagnetic signals, for instance for an automobile radio.

Such keyboards are designed for memorizing, in a presetting mode of operation, different positions of a movable tuning element, each position for a particular key, and for resetting the tuning element, during a resetting mode, to each different predetermined position by acting on the corresponding key.

Each key can assume two stable positions: an inoperative position in which the key establishes no electrical or mechanical connection and produces no information, thus permitting use of manual tuning, and a second or operative position which will be defined here as the resetting of tuning to a preselected transmitting station corresponding to the position of the key completely pushed in.

A keyboard of this type is described in the Italian Patent No. 1,021,917, and a type of key suited for this keyboard is described in the Italian Patent Application No. 52 129 An6, filed on November 11, 1976.

In the above-mentioned Patents, which disclose the general operation of this type of keyboard, with particular reference to the reduction of play among the various working elements, achieved through spring elements, a tuning tie bar is employed which works in conjunction with the ends of elbow levers which are pivoted on a frame plate. The function of these elbow levers is to engage the memorization plunger element of a corresponding key.

According to the present invention, there is provided a keyboard for use with a tuning mechanism for preselection of electomagnetic signals, comprising a fixed support frame plate, a plurality of keys arranged to slide transversally with respect to the plate and protruding from the front of the plate and provided with mechanical memory elements, a tie bar for key positioning and pick-up of mechanical play arranged to slide longitudinally along the frame plate, a slider controlled by the keys and arranged to slide longitudinally along the frame plate for disengaging a clutch device of the manual tuning mechanism, and a bracket pivoted in two upright appendixes integral with the frame plate and disposed at its sides, the bracket being arranged to oscillate around its pivots and to transversally sweep the surface of the plate. the bracket being arranged to be mechanically connected to the tuning mechanism so that movement of one determines the position of the other, the bracket being constantly urged towards the front of the plate by elastic means, and the mechanical memory elements of the keys being arranged to be preselected through contact between the memory elements and the bracket in order to establish desired positions of the tuning mechanism.

A preferred embodiment of the present invention may be used to replace the known system of connecting the tuning mechanism and the preselecting key, which is based on the translating action of the tie bar on the plane of the frame plate, and the rotating action of the elbow levers on the same plane of the frame plate, with a different and improved system of connection between the preselection keys and the tuning system consisting of a bracket pivoted in the area of the side ends of the frame plate and oscillating about its pivots, thus sweeping the plane of the frame plate.The number of elements which constitute the keyboard may thus be reduced with a consequent improvement in simplicity of construction also enabling the number of keys which may be applied to the frame plate, to be doubled while still maintaining the same operating accuracy and the same sturdiness in construction.

It is known that automobile manufacturers must comply with specific dimensional and constructional specifications (DIN 75500) concerning the space and louver allowed in the dash board of automobiles for the insertion and connection of a radio.

With the coming of automobile radios incorporating a cassette recording and replaying deck, which necessarily occupies a certain amount of the allowed space, the room left for the tuning preselection device is substantially reduced both in height and width. The research effort of automobile radio manufacturers is hence directed towards obtaining a predeterminable automatic tuning key board device which complies with safety of operation and sturdiness specifications, and that at the same time complies with the necessity of having to be contained in the space allowed by the above mentioned DIN specifications.

A preferred embodiment of the present invention provides a keyboard containing doublethe amount of keys possible with the keyboard illustrated in the Patent Specifications mentioned hereinbefore. This may be achieved by vertically utilizing the room at the side of the automobile radio space without further occupying the intermediate space taken by the frame plate of the keyboard.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic top view of a keyboard constituting a preferred embodiment of the invention; and Figure 2 is a schematic side view cross-section of the keyboard, along line ll-ll of Figure 1.

With reference to the drawings, reference number 1 indicates a frame plate of a keyboard. The frame plate is preferably a single piece obtained by casting.

A tie bar 2 for positioning and play pick-up is placed near the back side of the frame plate. The tie bar slides longitudinally and is guided between studs placed in the frame plate schematically indicated at 3.

The tie bar 2 is urged upwards by a spring 5 as viewed in Figure 1, and a stop 4, integral with the frame plate 1, arrests it at its uppermost position. The tie bar may be slided longitudinally against the action of spring 5 by pressing a turning knob 6, which operates through a lever 7 pivoted to the frame plate, thus resetting the keyboard. A series of pins 8 (one of which is shown in Figure 1) is disposed on the tie bar 2, each pin 8 matching a cam 9 of a respective key 10 (Figure 1). The cam 9 of each key lOis shaped so that, by pushing the key towards the back end of the frame plate, the tie bar 2 is translated against the action of its spring 5 by engaging with pin 8, which in turn locks the key.

As shown in Figures 1 and 2, a plurality of the keys 10 is mounted on each face of the frame plate 1. (In Figure 1 only one key of the whole sequence, mounted on the upper face of the frame plate 1, has been illustrated for sake of simplicity). To provide memory elements contained in the keys for preselection of tuning position, the keys 10 may be of the type described in the above mentioned Italian Patent Application No.52 129 A,76. These keys include a cap which, when pulled, disengages a pin 12 from a resilient appendix 13, thus freeing a plunger 14 which forms the memory element and is spring biased by a spring 15 in a direction towards engagement with a bracket element interlocked with the tuning, and which will be described later.However, the keys described herein differ from those disclosed in the Italian Patent Application 52 129 A/76 in that the keys 10 are guided in their sliding movement transversally with respect to the plate 1 through studs 16 moulded in the plate 1 and are limited by a peg 17 of the key and an abutment 18 integral with the frame plate. The keys 10 are driven towards their front protruding position, with respect to the frame plate, by a spring 19 between the frame plate 1 and the key 10. Holding back of the key 10 on the plane of the frame plate 1 is assured by covers 20 (Figure 2) attached to the frame plate 1.

A slider 21, disposed longitudinally with respect to frame plate 1 for controlling the disengagement of a friction clutch (not shown in the drawing) of the manual tuning mechanism controlled by the tuning knob (also not shown in the drawing), comprises a laminar elongate element guided by two pins 22 (Figure 1) attached to the basic frame plate 1 and coupled in corresponding slots machined in the slider 21 itself The slider is shown only schematically in the Figures, its function and arrangement being similar to the slider described in the previously mentioned Italian Patent No. 1,021,917. The configuration of the slider 21 is essentially of a saw tooth form, each tooth 23 (Figure 1) corresponding to a key 10. One end 24 (Figure 1) of the slider 21 is connected to the clutch device (not shown).The slider 21 is constantly under the action of a spring (not shown in the Figures) which drives it in the direction of direct translation towards the clutch device. The slider 21 is inserted in a cavity 25 (Figure 2) machined along the thickness of the plate 1. The slider 21 cooperates with cams 26 of the cap 11 of each key 10, which acts on the corresponding tooth 23, translating the slider 21 and disengaging the transmission of the mechanism controlling manual tuning and uncoupling the clutch device.

The sweeping element or bracket, identified in Figure 1 by 27, for performing the task of establishing the position of the memory elements or plungers 14 for automatic tuning preselection will now be described.

The frame plate 1 has vertical appendixes 28 placed at each side end of the plate itself and integral with it. The appendixes 28 have a V shaped notch 29, and two spring seats 30.

The sweeping element, or bracket, 27 consists of two vertical sections 31 and 31', each of which has a pivot 32 and 32' on its top.

Two horizontal sections 33 and 33' are rigidly attached to the lower ends of the vertical sections 31 and 31'.

The pivots 32 and 32' of the bar 27 are inserted in the V shaped notch 29 of the appendixes 28 and held in rotational engagement with the notch 29 by means of a spring 34 (Figure 2), placed in the seats 30 of the appendixes 28.

The horizontal sections 33 and 33' are placed respectively on the upper and lower faces of the frame plate 1, so that the bracket 27 may oscillate around the pivots 32 and 32'. The horizontal sections 33 and 33', during this oscillation, sweep the upper and lower surface of plate 1.

The pivot 32', situated on the side housing the tuning mechanism, is connected rigidly to the tuning mechanism itself so that a well determined angular asset of bracket 27 corresponds to each position of the said tuning mechanism.

This connection (not shown in the drawings for sake of simplicity) may be made in any suitable way, for example, by means of a worm screw and cogwheel mechanism.

The bracket 27 is limited in its stroke, on one side by a stop 35 (Figure 2), and on the other side by the covers 20 of the frame plate, the bracket being constantly urged by a spring 36 towards the front of the keyboard.

For preselection of a tuning position, therefore, the cap 11 of one of the keys 10 is pulled forward thus releasing the plunger 14. The tuning knob 6 is then turned to manually determine the tuning position which moves the bracket 27 to a particular location.

Finally the key 10 is fully pressed bringing the plunger 14 into contact with the horizontal section of the bracket 27, locking, at the same time, the plunger in position and resetting the cap 11 in its usual place. In thiswaythe plunger 14 memorizes the tuning position and, in a later automatic selection, the plunger 14, by coming into contact with the bracket 27, will move it exactly to the desired tuning position.

During the operation of automatic tuning through the key, the key itself will move the slider 21 releasing the clutch engagement of the manual tuning, as happens in other known types of keyboards.

By vertically utilizing the space at the side of the frame plate by means of the appendixes 28 and the vertical sections 31 and 31' of the bracket 27, the sweeping element is provided by means of one single component, namely the bracket 27, which may serve both the upper and lower face of the frame plate, thus allowing the number of keys permissible in the keyboard to be doubled.

Claims (9)

1. A keyboard for use with atuning mechanism for preselection of electromagnetic signals comprising a fixed support frame plate, a plurality of keys arranged to slide transversally with respect to the plate and protruding from the front of the plate and provided with mechanical memory elements, a tie bar for key positioning and pick-up mechanical play arranged to slide longitudinally along the frame plate, a slider controlled by the keys and arranged to slide longitudinally along the frame plate for disengaging a clutch device ofthe manual tuning mechanism, and a bracket pivoted in two upright appendixes integral with the frame plate and disposed at its sides, the bracket being arranged to oscillate around its pivots and to transversally sweep the surface of the plate, the bracket being arranged to be mechanically connected to the tuning mechanism so that movement of one determines the position of the other, the bracket being constantly urged towards the front of the plate by elastic means, and the mechanical memory elements of the keys being arranged to be preseiected through contact between the memory elements and the bracket in order to establish desired positions of the tuning mechanism.

2. A keyboard as claimed in claim 1, in which the bracket comprises two legs having the pivots at their upper ends and two elongate sections parallel and oextensive with the plate rigidly connected to the lower ends of the legs, the two sections being placed over respective opposite faces of the plate.

3. A keyboard as claimed in claim 1 or 2, in which the upright appendixes integral with the plate have respective V-shaped notches in which the pivots of the bracket are housed and held in place by elastic elements engaged with the appendixes.

4. A keyboard as claimed in any one of the preceding claims, in which the tie bar for positioning of the keys and for play pick-up is positioned at the rear of the plate.

5. A keyboard as claimed in any one of the preceding claims, in which the keys are guided in their transversal sliding action with respect to the plate by studs integral with the plate and disposed at the sides of the keys.

6. A keyboard as claimed in any one of the preceding claims, in which the slider for control of the disengagement of the tuning clutch device is disposed in a cavity machined in the thickness of the plate.

7. A keyboard as claimed in any one of the preceding claims, in which a first series of the keys is disposed on one face of the plate and a second series of the keys is disposed on the opposite face of the plate.

8. A keyboard for the preselection of electromagnetic signals, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

9. A radio including a keyboard as claimed in any one of the preceding claims.