Automatic headlamp switching system

In a vehicle having an accessory unit attached thereto, the combination of:

• a primary circuit including a primary light source, an energy source, and first switch means for connecting said energy source and said primary light source so that said primary light source is selectively energizable;
• a coupling means for selectively connecting and disconnecting said accessory unit to said vehicle;
• a secondary circuit including a secondary light source;
• and
• a second switch means connectable with said primary and secondary light sources and operative when said coupling means connects said accessory unit to said vehicle and when said second switch means is activated to interrupt the primary circuit from said energy source to said primary light source and simultaneously complete said secondary circuit from said energy source to said secondary light source, wherein said second switch means is activated by said first switch means.

In a vehicle having an accessory unit attached thereto, the combination of:

• a primary circuit on said vehicle including a primary light source, an energy source, and a switch for connecting said energy source and said primary light source so that said primary light source is selectively energizable;
• a secondary light circuit on said accessory unit including a secondary light source;
• a coupling means for selectively connecting and disconnecting said accessory unit to said vehicle;
• and
• switching means automatically activated when said accessory unit is coupled to said vehicle to interrupt said primary circuit and to connect said secondary light circuit to said energy source so that said secondary light source is selectively energizable by said energy source and said primary circuit is de-energized.

A wiring harness for use in attaching an accessory unit to a vehicle of the type that includes vehicle headlamp means, vehicle headlamp connector means, an energy source, and first switch means, said first switch means when activated selectively connecting said energy source to cause the illumination of said vehicle headlamp means, and said accessory unit including secondary headlamp means, said wiring harness comprising:

• a harness primary headlamp connector means for engagement with said vehicle headlamp means;
• a harness secondary connector means for engagement with said vehicle headlamp connector means;
• a coupling means for electrically connecting said wiring harness to said accessory unit;
• a second switch means for selectively controlling the illumination of said vehicle headlamp means and said accessory unit headlamp means, said second switch means connecting said energy source to said vehicle headlamp means when said first switch means is activated and when said coupling means is not electrically connecting said wiring harness to said accessory unit, and said second switch means connecting said energy source to said accessory unit headlamp means when said first switch means is activated and when said coupling means is electrically connecting said wiring harness to said accessory unit;
• and
• a conductor means operatively interconnecting said harness primary headlamp connector means, said harness secondary connector means, said coupling means, and said second switch means.

An accessory unit for attachment to a vehicle of the type that has a primary light circuit including a primary light source, an energy source, a first switch means for connecting said energy source and said primary light source so that when said first switch means is activated said primary light source is selectively illuminated, said accessory unit comprising:

• a material handling unit,
• coupling means for selectively connecting and disconnecting said accessory unit to said vehicle;
• a secondary light circuit including a secondary light source on said accessory unit;
• a second switch means connectable into said primary and secondary light circuits, said second switch means operative, when said coupling means connects said accessory unit to said vehicle and when said first switch means is activated, to interrupt said primary light circuit and simultaneously complete said secondary light circuit by connecting said energy source to said secondary light source so that said secondary light source is illuminated and said primary light source is not illuminated,
• and wherein said secondary light source is mounted on said material handling unit.

In a vehicle having an accessory unit attached thereto, the combination of:

• a primary circuit on said vehicle including a primary light source, an energy source, and a switch for connecting said energy source and said first primary light source so that said primary light source is selectively energizable;
• a secondary light circuit on said accessory unit including a secondary light source;
• and
• switching means for interrupting the primary circuit and for connecting said energy source to said secondary light source so that said secondary light source is selectively energizable in response to said switch.