Abstract: A lock for the ignition circuit of an automobile is disclosed. The lock includes a Hall effect sensor element which is activated by a control magnet on the cylinder member of the lock so that when the cylinder is rotated by a key to its start position the Hall effect sensor element is activated. The activation of the sensor element provides one of several starting criteria to an ignition circuit for starting an automobile. An anti-tampering magnet on the cylinder member lies directly under the sensor element in the off position and biases the Hall effect sensor element to its off position so hard that other magnetic forces induced from the exterior of the lock cannot overcome the bias and activate the sensor.

Abstract: The safety interlock prevents the starting of a device if one or more safety switches is not first cycled through its operational cycle. Since the safety switches must be operated before starting, the device will not operate if the switches have been tampered with or have failed. The interlock includes a digital memory unit connected to the switch which stores information indicative of the cycling of the switch. The output of the memory unit is interconnected with the starting system of the device such that starting is prevented unless the stored information indicates that each switch has been cycled. In a preferrred embodiment the interlock includes a microprocessor.

Abstract: The present invention discloses an engine primer bulb assembly having a base, a primer bulb and a retaining ring for securing the primer bulb to the base. The retaining ring is self-locking and provides a circumferential force against the bulb to seal it with the base to provide a primer chamber.

Abstract: An adjustable ignition shut-off switch for lawnmower engines is disclosed in which a tab attached to the bale lever moves a resilient switch contact away from a ground terminal when the lawnmower is in its run position. When the bale lever is released, the tab disengages the switch contact, permitting the resilient switch contact to make an electrical connection with the ground terminal. Since the switch contact is also electrically connected to the engine ignition system, ignition pulses are grounded to stop the engine when the switch contact is electrically connected to the ground terminal. The height of the tab is adjustable so that the shut-off switch may be adapted to different lawnmower applications.