Abstract: A downrigger for releasably retaining a fishing line terminated by a lure and including a fishing line retainer for releasing the fishing line when a fish strikes. An alarm may be activated in response to the release. The downrigger is configured to reflect sonar signals for indicating the depth of the fishing line retainer. The downrigger is constructed to attach rotatably and removably to a cleat on a fishing vessel. The downrigger line may be electrically conductive to transmit the alarm signal on release of the fishing line.

Abstract: A temperature sensor indicates imminent mechanical failure of a device by detecting a sharp rise in temperature of the device above a normal operating temperature range. The sensor is a flexible container filled with a signal fluid and closed by a plug having a melting point which is above the normal operating temperature range of the device. Tube flexure allows it to conform substantially to the shape of a surface on the device being monitored. Flexing the tube changes its internal pressure but has no effect on the plug, which responds only to changes in temperature.

Abstract: A rotatable reflector for bicycles has a timer which intermittently completely halts rotation of the reflector in sequential positions in response to rotation of the reflector but independently of angular movement of a bicycle wheel. The reflector displays a changing colored reflective surface above a stationary housing of a contrasting color. The timer is liquid actuated and can be accurately calibrated by varying the viscosity of the liquid in the timer. Timed display of contrasting colored portions of the reflector attracts the attention of passing motorists by displaying a signal which appears to blink and change colors. The period during which each contrasting color is displayed is constant regardless of the velocity of the bicycle or relative wind velocity.