Lever Return Spring

A return spring, or restoring spring, is a coil spring that moves something, such as a valve or diaphragm back to its normal position and holds it there.

Lighting Circuit

The automobile lighting circuit includes the wiring harness, all the lights, and the various switches that control their use. The complete circuit of the modern passenger car can be broken down into individual circuits, each having one or more lights and switches. In each separate circuit, the lights are connected in parallel, and the controlling switch is in series between the group of lights and the fuse box. The parking lights, are connected in parallel and controlled by a single switch. In some installations, one switch controls the connection to the fuse box, while a selector switch determines which of two circuits is energized. The headlights, with their upper and lower beams, are an example of this type of switch. Again, in some cases, such as the courtesy lights, several switches may be connected in parallel so that any switch may be used to turn on the lights.

Lifter Body

The valve lifter body houses the valve lifter mechanism. The valve lifter is the unit that makes contact with the valve stem and the camshaft. It rides on the camshaft. When the cam lobes push it upwards, it opens the valve.

Limiting Coil and Operating Coil

The limiting coil passes the current from the battery to the common connection of two coils at the lower terminal on the dash unit. This current may pass from either the operating coil of the dash unit and the other over to the tank sending unit. When the fuel tank is low or empty, the sliding brush cuts out all resistance in the tank unit. Then the current will passes through the tank unit circuit because of the low resistance, and only a small portion will pass through the operating coil to the dash unit. This coil is not magnetized enough to move the dash unit pointer, which is then held at the "Empty" position by the limiting coil.

When the tank is full or partly full, the float of the tank unit will rise to the surface of the fuel and move the sliding brush over the rheostat, putting resistance in the tank unit circuit. This results in more current will then passing through the operating coil to give a magnetic pull on the pointer, which overcomes some of the pull of the limiting coil. When the tank is full, the tank unit circuit contains the maximum resistance to the flow of the current. The operating coil will then receive its maximum current and exert pull of the pointer to give a "Full" reading. As the tank empties, the operating coil loses some of its magnetic pull and the limiting coil will still have about the same pull so that the pointer is pulled Toward the lower reading.

Top