GB2056711A - Electrical position-control device - Google Patents

Abstract

A device for controlling the orientation of a floodlight, includes a manually-operable electrical switching (11), having a plurality of predetermined positions, and an electric motor (13), controlling, through an actuator, the position assumed by a control rod for the floodlight. A second electrical switching means (15), mechanically operated by the motor (13), is positioned in correspondence to predetermined positions of the control rod. The switches are so interconnected that the motor until the control rod has reached a manually predetermined position. In order to prevent overshoot of the predetermined position due to the inertia of the floodlight positioning mechanism the second switching means (15) is arranged to short- circuit the supply terminals of the motor (13) when the control rod attains the predetermined position. <IMAGE>

Description

SPECIFICATION Electrical control device for controlling the orientation of a floodlight This invention relates to an electrical control device for controlling the orientation of apparatus, for example floodlights, in particular, but not exclusively, vehicle head lamps.

In particular, the present invention relates to a device for the type comprising: first manually operable electrical switching means arranged to assume a plurality of predetermined positions, with each of which there being associated a corresponding configuration of electrical connections; an electric motor; actuator means operated by the electric motor for controlling the orientation of the floodlight; second electrical switching means, mechanically operated by the motor and arranged to assume a plurality of positions, with each of which there corresponds a predetermined position of the actuator means and a predetermined configuration of electrical connections; the second electrical switching means being arranged to cooperate with the first electrical switching means in order to connect the motor to an electrical supply source until the actuator means have reached a predetermined position corresponding to a manually chosen position in the first electrical switching means. Any control device of the type heretofore described is indicated hereinafter for brevity as a "control device of the type heretofore specified".

In known control devices of the type heretofore specified, when the actuator means attain the said predetermined position, the second electrical switching means, which generally comprise a rotary switch, cut off the supply to the electric motor which consequently stops.

In practice, as the motor and the actuator means together possess.a considerable mechanical inertia, the motor still continues to rotate briefly after the moment in which the supply is cut off. Consequently, the final position assumed by the actuator device is indeterminate overall, as is the inclination given to the floodlight by actuator means.

The object of the present invention is to provide a device for controlling the orientation of a floodlight which is free from the aforesaid drawback of known devices.

The present invention provides a device of the type heretofore specified for controlling the orientation of a floodlight, in which the motor is effectively connected in series with the first and second switching means, and when the actuator means attain the said predetermined position, the switching means short-circuit the supply terminals of the motor.

A preferred embodiment of the invention will now be described by way of non-limiting example, with reference to the accompanying drawings in which: Figure 1 is an operating diagram of the electrical control part of a control device according to the present invention; Figure 2 is a perspective view from above of a mechanically assembled detail of Fig. 1; and Figures 3, 4 and 5 are elevational and sectional views of three different embodiments of actuator means for the device according to the present invention.

Fig. 1 shows the electrical part, indicated overall by 10, of a device for controlling the orientation of a floodlight, in particular a vehicle headlamp. The electrical part 10 comprises substantially a double preselection switch 11, a two-way inverter 1 2 mechanically operated by the switch 11, a pair of motors 1 3, 14, two switches 15, 1 6 operated respectively by said motors, and a connector block 9 comprising eight pairs of connection terminals indicated respectively by the numbers 1 to 8 and 1' to 8'. The double switch 11 comprises a pair of annular conducting tracks 17, 18 deposited on support discs 51, 52. These latter are rotatable about their axis of symmetry such that each annular track 17, 1 8 slides relative to a respective direct current supply brush 19, 20.The tracks 17, 1 8 which are coupled together angularly, have respectively a radial cavity 21 and a radial appendix 22 in equal respective angular positions.

In addition, four equally spaced-apart coliector brushes 23 rest on the track 1 7 and are in electrical contact with said track 1 7 only in proximity to the outer peripheral edge thereof, so that they do not come into electrical contact with the track at the cavity 21. Likewise, four equidistant collector brushes 24 are disposed about the annular track 18, their distance from the centre of said track being greater than the outer radius of the track, and being such as to allow electrical contact between each of said brushes and the radial appendix 22.

The inverter 1 2 is constituted by a pair of double-throw switches 27, 28, each of which has a common terminal 29, 30 connected respectively to the terminal 7' and terminal 6' of the block 9. The double-throw switches are also provided with a first and second switching terminal 31, 33 and 32, 34 respectively.

The double-thrown switches 27, 28 constituting the inverter 1 2 assume either the position shown in Fig. 1 or an opposite position, according to the direction of rotation imposed on the annular tracks 17, 1 8 of the double switch 11.

The letters a, b, c, d and e indicate four angular positions which said tracks can assume. In particular, position a can be assumed only by the tracks 17, 1 8 making a complete rotation in a clockwise direction, while position e, which coincides angularly with position a, can be assumed only by said tracks 17, 18 making a complete rotation in the anti-clockwise direction.

The rotary switch 1 5 comprises an annular track 36 deposited on a relative support base 40 and comprising on its outside five semicircular cavities, of which four are spaced apart by 90 , while the fifth is disposed between two of these latter. A semicircular conducting portion 38 suitably spaced from the facing edge of the track 36 is deposited inside'each cavity 37. A radial rotary brush 39 is also provided, carrying a contact element (not shown) arranged to slide only in proximity of the outer peripheral edge of the track 36 and portions 38, and in particular having a thickness less than the space between each portion 38 and the track 36 in order to prevent any short-circuiting between these latter.

With regard to the switch 11, the brushes 23, 24, with which the letters a, b, c, d are respectively associated, are connected together and connected respectively to the terminals 1', 2', 3' and 4' of the block 9. The terminal 5' of said block is connected to the switching terminals 34 and 31 of the inverter 1 2 and to the supply brush 19, and the terminal 8' of said block is connected to the switching terminals 32 and 33 of the inverter 1 2 and to the supply brush 20. In the block 9, the terminals 1' to 8' are connected respectively to the terminals 1 to 8 of the block 9. The terminals 2, 3 and 4 are connected to corresponding conducting portions 38 indicated by the side letters b, c, d, and the terminal 1 is connected to two adjacent conducting portions 38 indicated by the side letters a and e.The terminal 5 of the block 9 is connected to the annular track 36, the terminals 6 and 7 are connected to opposite poles of a direct current supply source, for example a supply battery of said vehicle, and the terminal 8 is connected to a first supply terminal of the motor 13, the second terminal of which is connected electrically to the brush 39.

The terminals 1, 2, 3, 4, 5 and 8 are connected to the motor 14 and the rotary switch 1 6 in a manner which is not illustrated but is analogous to that described with reference to the motor 1 3 and switch 1 5.

Fig. 2 shows an assembly example of the double switch 11 and inverter 12. In particular, the annular tracks 1 7 and 18 of the switch 11 are conducting tracks of a printed circuit deposited on said insulating support disc 51, 52 respectively, each of which is torsionally coupled to a shaft 53 which also operates the inverter 12. Said shaft 53 can be rotated about its axis by a knob 54, and has keyed on to it a disc 55, the surface of which comprises the circular concave seats 56.

These latter are arranged to cooperate with a ball b7 urged into contact with the surface of the disc 56 by the action of a cylindrical spring 58 which is compressed inside a cup support element 59 connected to the support frame (not shown) of the switch 11. Finally, a radial pin 60 cooperates with a helical groove 61 in the shaft 53 over an angle of 360 , in order to prevent said shaft and thus the discs 51 and 52 from making an angular rotation greater than one complete revolution.

A positioning unit is associated with each rotary switch 15, 1 6 in a manner not illustrated, this unit comprising a disc with concave seats for snap-engaging by a ball in a manner similar to that described with reference to the disc 55 and ball 57, in order to ensure correct positioning of the brush 39 at each conducting portion 38.

Fig. 3 shows an actuator device, indicated overall by 100, for transmitting an axial translatory movement to a control rod 101 for a floodlight, not shown.

The device 100 comprises substantially a motor, for example the motor 1 3 of Fig. 1, a speed reduction unit 102 and a unit 103 for converting rotary motion into translatory motion, these being contained within a substantially tubular casing 104 closed at opposite ends by covers 105 and 106 respectively.

The reduction unit 102 is an epicyclic unit, and comprises substantially a ring gear 107 provided in the casing 104, a planetary gear 108 driven by a pinion 109 carried by the shaft 110 of the motor 13, and also engaging with the fixed ring gear 107 and a ring gear 111. This latter is rotatably mounted about its axis and is provided with a number of teeth which differs from the number of teeth of the ring gear 107 for example by one tooth. The ring gear 111 is provided in one end of a cylindrical member 112, the other end of which extends in the form of a pin 11 3 housed in a seat correspondingly provided in the cover 106.The cylindrical member 11 2 forms part of the converter unit 11 3, and comprises on its lateral surface a helical groove 114 which is engaged by a tooth 115 extending radially towards the inside of the casing 104 through a slot 11 6 provided in a side wall 11 7 of the casing 104.

The tooth 11 5 forms part of a slide 11 9 slidable axially along a pin 120 housed in a seat 121 provided in the outer surface of said side wall 11 7. The slide 11 9 comprises a tubular appendix 1 22 which extends outside the side wall 11 7 and is coupled -to a threaded portion 123 of the rod 101. The brush 39 of Fig. 1 is mounted rigid with the pin 113, and rests on the annular track 36 (not visible in Fig. 3) deposited on the support board 40. Finally, a connector block 125 extends outwards from the cover 106 to enable the track 36 and motor 1 3 to be electrically connected to the terminals 1, 2, 3, 4, 5 and 8 of the block 9 of Fig. 1. Fig. 4 shows an actuator device, indicated overall by 150, for controlling the axial position of a control rod 151 for a floodlight, not shown. The device 1 50 comprises a motor, for example the motor 1 3 of Fig. 1, a speed reduction unit 1 52 and a unit 1 53 for converting rotary motion into translatory motion. These units, together with the motor 13, are contained inside a substantially tubular casing 1 54 closed upperly and lowerly by respective covers 1 55 and 156, and comprising internally a longitudinal dividing wall 1 57 and a transverse dividing wall 1 58 defining overall two lower chambers 1 59 and 160 and two upper chambers 161 and 162.The chamber 159 houses the motor 13, of which the shaft 1 63 has keyed thereon a pinion 1 64 coupled with a ring gear 1 65 rotatably mounted about a support pin 1 66. On this latter there is keyed a pinion 1 67 coupled to a ring gear 1 68 which rotates about a relative pin 1 69 carrying a pinion 1 70. By way of a planetary gear 171, said pinion 1 70 engages with a fixed ring gear 1 72 formed in the casing 154, and is also rotatable about a support pin 1 73 carried eccentrically by a disc 1 74 angularly coupled to one end of a shaft 1 75. At the other end to the disc 174, the shaft 1 75 supports a spiral guide 176, with which a slide 1 77 cooperates. This latter is mounted rigid with a tubular member 1 78 into which a threaded portion 179 of the rod 151 is screwed. This tubular member 1 78 is arranged to slide axially in a tubular guide 180 comprising a radial slot 181, in which said slide 1 77 slides.The board 40 carrying the track 36 on which said brush 39 slides (see Fig. 1) is connected to an inner lateral wall of the casing 1 54 bounding the chambers 1 59 and 1 61. Said board 40 can be connected electrically to the outside by means of a connector block 182, so enabiing the switch 1 5 and motor 1 3 to be supplied in accordance with the diagram of Fig. 1. Fig. 5 shows an actuator device, indicated overall by 200, arranged to transmit a translatory movement to a rod 201 of a floodlight, not shown.

The device 200 comprises a motor, for example the motor 1 3 of Fig. 1, a speed reduction unit 202 and a unit 203 for converting rotary motion into translatory motion, these being substantially contained in a casing 204. This latter comprises a lower tubular portion 205 closed lowerly by a cover 206 and containing the motor 13, said portion 205 being connected upperly to a cup portion 207 in which the reduction unit 202 and converter unit 203 are substantially housed.

A worm 209 is keyed on to the shaft 208 of the motor 13, and cooperates with a helical gear 210 rotatably mounted between two intermediate walls, 211 a, 21b which extend parallel to each other inside the casing 204 from an upper wall of the cup member 207.

Said helical gear 210 is rotatable about a support pin 212 on which is keyed a pinion 213 which itself engages with a ring gear 214 carried by a shaft 215. The shaft 215 is torsionally coupled to a spiral guide 21 6 extending outside the casing 204, and coupled to a slide 21 7 mounted rigid with a tubular member 218. This latter is internally threaded and is engaged by a threaded portion 219 of the rod 201, and is further slidable in a tubular guide 220 comprising a radial slot 221 in which the slide 217 can move.

At the other end to that angularly coupled to the spiral guide 216, the shaft 215 supports the brush 39 indicated in Fig. 1, which can slide on said board 40. Finally, a connector block 222 is provided to enable the motor 1 3 and the tracks provided on the board 40 to be electrically connected to the outside.

The operation of the electrical part 10 of the control device according to the invention will now be described with particular reference to Fig. 1, in which the terminals 42 and 41 are assumed to be connected respectively to the positive and negative pole of a direct current supply source, for example the accumulator of said motor vehicle. It will also be assumed that the rest position of the tracks 1 7 and 18 of the switch 11, as shown in Fig.

1, has been reached by making a complete clockwise rotation of the switch to attain the position indicated by the letter a.

Under these conditions, a positive voltage signal is fed to the annular track 1 7 by way of the double-throw switch 27 and supply brush 19, and a negative signal is fed to the track 1 8 by way of the double-throw switch 28 and supply brush 20. A positive signal is also fed to the annular track 36 by way of the doublethrow switch 27, and to the conducting portions 38 bearing the letters b, c, d by way of the collector brushes 23 which receive said signal from the annular track 1 7. Finally, a negative voltage signal is fed to the first connection terminal of the motor 1 3 by way of the double-throw switch 28, and the conducting portions 23 bearing the letters a and e are also connected to the negative pole by the collector brush 24 which rests on the radial appendix 22 of the annular track 1 8.

As the second terminal of the motor 1 3 is connected via the brush 39 to the conducting portion 38 of negative voltage, said motor 1 3 has its opposing terminals short-circuited, be cause of which it is kept at rest as it is not electrically supplied. The brush 39, to which the various motion transmission units illustrated in Figs. 3 to 5 are connected, is therefore kept at rest in the angular position indicated by the letter a.

It will be assumed that the double switch 11 is now moved into the position indicated by b. As this position is reached by a rotation in the anti-clockwise direction, i.e. in the opposite direction to that made previously for reaching position a, the inverter 1 2 is consequently changed over, so that the double throw switches 27 and 28 now respectively connect the common terminals 29 and 30 to the respective switching terminals 32 and 34.

In consequence of this switching operation, a negative voltage signal is fed to the track 1 7 while a positive signal is fed to the track 18.

A positive signal is also fed to the first terminal of the motor 13, while a negative signal is fed to the track 36 in which the conducting portions 38 bearing the letters a, e, c, d are also at negative voltage as they are connected to the respective brushes 23 resting on the annular track 1 7. The only exception is the conducting portion 38 in position b which is at positive voltage, it being supplied by the collector brush 24 which in position b cooperates with the appendix 22 of the annular track 1 8. Thus a positive signal reaches the motor 1 3 from the terminal 8 and a negative signal reaches it from the brush 39.Consequently, said motor operates and rotates the brush 39 anti-clockwise, this overcoming by inertia the space between the portion 38 in position a and the annular track 36, and thus sliding on said track until it reaches the conducting portion 38 in position b. Under these conditions, two positive voltages are present at the opposing terminals of the motor 1 3. The motor 1 3 is therefore short-circuited so that its rotation stops suddenly and the brush 39 is kept in the conducting position 38 in position b. The said positioning unit, in which said ball engages in a corresponding concave seat present in the disc facing it, also helps to maintain correct positioning of the brush 39.

In this manner, the brush 39 is prevented from stopping in the space between the portion 38 and the track 36, in which it would not be able to receive any further electrical supply signal to feed to the motor 13.

A further angular movement of the double switch 11 progressively towards the positions c, d, e is effected by the motor 1 3 and rotary switch 1 5 in the manner heretofore described for attaining position b.

Any reversal in the rotation given to the switch 11, for example for attaining position a, immediately causes the inverter 1 2 to return to the position shown in Fig. 1 and thus a reversal in the polarity of the supply signal fed to the motor 13, which therefore begins to rotate clockwise.

The motor 14 interlocked with the rotary switch 1 6 partly shown in Fig. 1 behaves in a like manner. The behaviour of this unit is however totally separate from the behaviour of the motor 1 3 and relative track 36.

The operation of the actuator devices 100, 1 50 and 200 illustrated in Figs. 3, 4 and 5 respectively is described hereinafter briefly, as this operation is substantially obvious.

With particularly reference to Fig. 3, the rotation of the shaft 110 of the motor 1 3 is transmitted by the pinion 109 and planetary gear 108 to the ring gear 111, which rotates the helical guide 11 4 formed in the cylindrical member 11 2. The angular position assumed by said member 11 2 determines the consequent axial position of the slide 11 9 relative to the support pin 120, because the tooth 11 5 of said slide engages with the helical guide 11 4 and moves in the slot 11 6 according to the angular position assumed by the cylindrical member 11 2.

With particular reference to Fig. 4, the rotation of the shaft 1 63 of the motor 1 3 is transmitted by the pinion 1 64, the gear wheel 1 65 and the relative pinion 1 67 to the gear wheel 168, the pinion 1 70 of which cooperates with the planetary gear 171 and the ring gear 1 72 to rotate the disc 1 74 and thusthe spiral guide 1 76. By means of a system of known type; this latter engages with the slide 1 77 to move it axially in the relative tubular guide 180, and with it the rod 1 51 which controls said floodlight.

With particular reference to Fig. 5, the rotary motion of the shaft 208 of the motor 1 3 is transmitted by the worm 209 and helical gear 210 to the pinion 213, which itself engages with the ring gear 214. Consequently, this latter rotates together with the shaft 215, and by way of the spiral guide 216 transmits a translatory movement to the slide 217, which thus slides axially in said tubular guide 220 carrying with it the control rod 201 for said floodlight. From an examination of the characteristics of the present invention, it can be seen that the corrector device according to the invention enables the aforesaid objects to be attained.

In particular, on reaching the predetermined position, the terminals of the motor 1 3 are short-circuited to ensure immediate stoppage of the motor and thus absolute precision in the position attained. The precision of the positioning of the brush 39 is further improved, taking account of said positioning unit which maintains the brush 39 in contact with the portion 38 until a different electrical displacement signal is received.

The particular configuration of the conductins tracks 17, 18 of the switch 11, and the conducting track 36 of the switch 1 5 enable five different angular rest positions to be obtained at choice, although having available only four collector brushes for each track 17, 18.

Finally, the total separation of the control between the motors 1 3 and 14 is particularly advantageous, each of these being independent in-that it is served only by the relative rotary switch 15, 16, and therefore is not influenced by any operational faults in the other. It is apparent that modifications can be made to the orientation control device according to the present invention without leaving the scope of the inventive idea.

For example, the conducting portions 38 associated with the letters a and e could be connected respectively in a stable manner to negative and positive supply poles, using for example in each case two pairs of diodes which take a signal from downstream of the switch 12. The collector brushes 23 and 24 of the double switch 11 relative to the positions indicated by a and e could then be dispensed with. The positions a and e in the rotary switch 1 5 can only be attained by the brush 39 at the end of a complete clockwise and anti-clockwise rotation respectively, at which the relative conducting portions 38 must be at negative and positive potential respectively, whereas the potential assumed by said portions when the brush 39 of the switch 1 5 moves towards one of the positions b, c, d is of no importance.Consequently, the motor 1 3 is always stopped when the mobile brush 39 of the switch 1 5 reaches one of the end positions on termination of a complete clockwise or anti-clockwise rotation.

The modification heretofore described is of particular importance in preventing faults or stalling of the motor 1 3 following errors in the manipulation of the double switch 11. In order to better understand this, it will be assumed that the switch 11 is moved from position a to position d, and that during the movement of the brush 39, said switch is brought into position c before the brush 39 has reached this latter position.

With reference to the diagram of Fig. 1, the supply polarity of the motor 1 3 would have been reversed, with instantaneous reversal of the direction of rotation thereof, because of which not only would the brush 39 never have reached position c, but on reaching the end position a the motor 1 3 would not have stopped, so transmitting to the relative converter 100, 1 50 or 200, mechanical stresses which could have damaged the converter itself. With the modified connection heretofore described, such a drawback is totally overcome, because when the brush 39 connected to the second terminal of the motor 1 3 reaches the end position a or e, the relative conducting portion 38 is at the same potential as the first terminal of the motor 13, because of which this latter is obliged to stop.

Wide modifications can be made to the structure of the switches 11, 15, and particularly to the relative conducting tracks 17, 1 8 and 36, which for example could extend through an arc of a circle less than 360 , or could be linear. In this latter case, a modification would have to be correspondingly made to each actuator 100, 1 50 or 200, for exam ple by making the brush 35 operated by a slide which slides rigidly with the rod of said floodlight.

Finally, although said device has been described for preferably controlling the orientation of a vehicle headlamp, it could be advantageously used for remote control of the orientation of any floodlight, or of an antenna.

Claims (9)

1. A device for controlling the orientation of an apparatus, of the type comprising first manually operable electrical switching means arranged to assume a plurality of predetermined positions, with each of which there being associated a corresponding configuration of electrical connections; an electric motor; actuator means operated by the electric motor for controlling the orientation of the apparatus; second electrical switching means, mechanically operated by the mot and arranged to assume a plurality of positions, with each of which there corresponds a predetermined position of the actuator means and a predetermined configuration of electrical connections, the second electrical switching means being arranged to cooperate with the first electrical switching means in order to connect the motor to an electrical supply source until the actuator means have reached a predetermined position corresponding to a manually chosen position in the first electrical switching means, the motor being effectively connected in series with the first and second switching means, and when the actuator means attain the said predetermined position, the second switching means short-circuit the supply terminals of the motor.

2. A device according to claim 1 in which the actuator means is arranged to convert rotary motion of the shaft of the motor into translatory motion in order to control the position assumed by a control rod for the floodlight.

3. A device as claimed in claim 1 or 2, in which the first electrical switching means comprise a first and second annular conducting track angularly coupled together and rotatable about the same axis, each of the tracks cooperating with a respective supply brush for connection to a respective pole of a direct current supply source, there being further provided a first and second group of radial collector brushes disposed respectively about the first and second track and electrically connected together in pairs; the first and second track respectively comprising a radial cavity and a projection, the first and second group of brushes being mounted at a radial distance from the relative track such that when a collector brush of said first group engages with the cavity, a corresponding collector brush of said second group cooperates with the projection; and the second electrical switching means comprise a fixed annular track in which there is provided a plurality of angularly spaced-apart conducting portions electrically insulated from said annular track, each conducting portion being connected to a respective pair of said collector brushes, there being also provided a rotary brush operated by the motor and slidable on said annular track so that it becomes connected alternately with portions of said track and with each of said conducting portions; opposite poles of said supply source being connected to said annular track and to a first terminal of the motor respectively, the second terminal of the motor being connected in series with the rotary brush.

4. A device as claimed in claim 3, comprising an inverter electrically connected between the supply brushes for said tracks and the opposite poles of the supply source; the Inverter being angularly coupled to the first and second tracks and being arranged to connect the brushes to a first and second pole of the opposite poles respectively, or vice versa, according to the direction of rotation followed in manually operating the first and second annular tracks.

5. A device as claimed in one of the preceding claims, comprising resilient snap coupiing means angularly connected to the first and/or secpnd switching means in order to prevent the switching means fluctuating about the respective said predetermined positions.

6. A device as claimed in claim 5, in which the resilient coupling means comprise a pair of facing elements, of which one is fixed and one is rotatable, and urged into contact by the action of resilient means; one of said elements comprising at least one convex portion, and the opposite one comprising at least one concave portion arranged for engagement by said convex portion.

7. A device as claimed in one of the preceding claims, in which the actuator means comprise a unit for converting rotary motion into translatory motion; the unit comprising a substantially cylindrical member rotatable about its axis as a result of mechanical action exercised by the motor, and provided with a helical groove on a side surface, and a slide axially slidable along a support shaft and carrying a radial tooth which engages in the helical groove.

8. A device as claimed in one of the preceding claims, in which the apparatus is a floodlight.

9. A device according to claim 9 in which the floodlight is a motor vehicle headlamp.

1 0. A device for controlling the orientation of a floodlight, substantially as described with reference to the accompanying drawings.