Headlamp levelling system

Claim 2

A headlamp levelling system for a road vehicle, comprising a two terminal d.c. electric motor operable to drive a linearly movable member coupled to a headlamp for adjusting the headlamp in a manner to vary the direction of the light beam emitted by the headlamp; an electrical supply across the terminals of which the motor is connected by way of an electrical circuit including a plurality of spaced pairs of fixed electrical contacts and first and second switch means operated by a common operating member; and a rotatably mounted conductive bridging member associated with said pairs of fixed electrical contacts, the conductive bridging member undergoing rotational movement relative to said pairs of fixed electrical contacts in response to linear movement of said driven member so that, in each of a plurality of discrete positions of the driven member and hence said headlamp, the bridging member electrically connects all but a respective pair of said fixed contacts; the first switch means including a plurality of normally open switches, one for each of said pairs of contacts, and being movable between a plurality of switch positions in each of which one of said normally open switches is closed to supply current to the motor to move said driven member until it reaches the discrete position in which the pair of contacts associated with said closed switch are not electrically connected by the bridging member, whereupon the supply of current to the motor is terminated; and said second switch means being operable to reverse the connections between the motor and the terminals of the electrical supply when the first switch means is moved from one switch position to a further switch position after its preceding movement had been from said further position to said one position.

Claim 3

A system as claimed in claim 1, and further including a second two terminal d.c. electric motor operable to drive a second linearly movable member coupled to a second headlamp for adjusting the second headlamp in a manner to vary the direction of the light beam emitted by the second headlamp; said second motor being connected across the terminals of said electrical supply by way of an electrical circuit including a plurality of spaced further pairs of fixed electrical contacts and said first and second switch means; and a second rotatably mounted conductive bridging member associated with said further pairs of fixed electrical contacts, the second bridging member undergoing rotational movement relative to said further pairs of fixed electrical contacts in response to linear movement of said second driven member so that, in each of a plurality of discrete positions of the second driven member and hence said headlamp, the second bridging member electrically connects all but a respective pair of said further fixed electrical contacts; the first switch means including a plurality of further normally open switches, one for each of said further pairs of contacts, and being movable between a plurality of further switch positions in each of which one of said further normally open switches is closed so that said further closed switch serves to supply current to the second motor to move said second driven member until it reaches the discrete position in which the further pair of contacts associated with said further closed switch are not electrically connected by the second bridging member; and said second switch means being operable to reverse the connections between said second motor and the terminals of the electrical supply when the first switch means is moved from one switch position to a further switch position after its preceding movement had been from said further position to said one position.

Claim 4

A system as claimed in claim 1, wherein said first and second switch means form part of an electrical switch assembly including a fixed part, said common operating member being mounted for angular movement relative to the fixed part about an axis of the operating member; first contact means movable with the operating member to control in turn operation of the plurality of electrical switches of the first switch means; second contact means coupled to the operating member so as to be capable of a limited degree of angular movement with the operating member to control said second switch means; and fixed abutment means carried by the fixed part to prevent said second contact means undergoing more than said limited degree of angular movement, the arrangement being such that said operating member is movable relative to said second contact means, when the latter is held by said abutment means.

Claim 5

A system as claimed in claim 3, wherein the second contact means is supported by a carrier assembly including a plate formed with at least one arculate slot in which said abutment means is slidably received so that the opposite ends of the slot define the limits of the permitted angular movement of the second contact means.

Claim 6

A system as claimed in claim 4, wherein the carrier assembly is mounted on the operating member for angular movement relative thereto and supports a fixed component of a detent mechanism for releasably retaining the operating member in a plurality of spaced angular positions, the movable component of the detent mechanism being rigidly connected to the operating member so that the detent mechanism serves to couple the carrier assembly to the operating member during said limited degree of angular movement of the second contact means.

Claim 7

A system as claimed in claim 5, wherein the fixed component of the detent mechanism is defined by a spring-urged ball and the movable component is defined by a toothed wheel, said ball being urged between successive adjacent teeth of the wheel in said angular positions respectively of the operating member.

Claim 8

A headlamp levelling system for a road vehicle, comprising a two terminal d.c. electric motor operable to drive a linearly movable member coupled to a headlamp for adjusting the headlamp in a manner to vary the direction of the light beam emitted by the headlamp; an electrical supply across the terminals of which the motor is connected by way of an electrical circuit including switch means and a plurality of spaced pairs of fixed electrical contacts; and a rotatably mounted conductive bridging member associated with said pairs of contacts, the bridging member undergoing rotational movement relative to said contacts in response to linear movement of said driven member so that, in each of a plurality of discrete positions of the driven member and hence the headlamp, the bridging member electrically connects a single, different pair of said electrical contacts; said switch means including a plurality of normally closed switches, one for each of said pairs of contacts, and being movable between a plurality of switch positions in each of which one of said normally closed switches is open so that when the switch means is moved to open one of said switches, current can flow to the motor to move the driven member until the bridging member electrically connects the pair of contacts associated with said open switch, whereupon the supply of current is terminated.

Claim 9

A headlamp levelling system for a road vehicle, comprising a two terminal d.c. electric motor operable to drive a linearly movable member coupled to a headlamp for adjusting the headlamp in a manner to vary the direction of the light beam emitted by the headlamp; an electrical supply across the terminals of which the motor is connected by way of an electrical circuit including switch means and a plurality of spaced pairs of fixed electrical contacts; and a rotatably mounted conductive bridging member associated with said pairs of contacts, the bridging member undergoing rotational movement relative to said contacts in response to linear movement of said driven member so that, in each of a plurality of discrete positions of the driven member and hence the headlamp, the bridging member electrically connects a single, different pair of said electrical contacts; said switch means including a plurality of normally closed switches, one for each of said pairs of contacts, and being movable between a plurality of switch positions in each of which one of said normally closed switches is open so that when the switch means is moved to open one of said switches, current can flow to the motor to move the driven member until the bridging member electrically connects the pair of contacts associated with said open switch, whereupon the supply of current is terminated.

Claim 10

A system as claimed in claim 7, and further including a second two terminal d.c. electrical motor operable to drive a second linearly movable member coupled to a second headlamp for adjusting the second headlamp in a manner to vary the direction of the light beam emitted by the second headlamp; said second motor being connected across the terminals of said electrical supply by way of a further electrical circuit including said switch means and a plurality of spaced further pairs of fixed electrical contacts; and a second rotatably mounted bridging member associated with said further pairs of electrical contacts, the second bridging member undergoing rotational movement relative to said further pairs of electrical contacts in response to linear movement of said second driven member so that, in each of a plurality of discrete positions of the second driven member and hence said second headlamp, the second bridging member electrically connects a single different pair of said further electrical contacts; said further electrical circuit connecting each of said normally closed switches of the switch means to a respective further paid of electrical contacts so that when the switch means is moved to open one of said switches, current can flow to the second motor to move said second driven member until the second bridging member electrically connects the further pair of contacts associated with said open switch.