Abstract: A tamper resistant and tamper-proving odometer construction. Driving of the odometer mechanism in the reverse direction to lower the count is prevented by a one-way locking mechanism associated with the lowest order digit wheel. A marking mechanism is associated with the two highest order digit wheels to clearly indicate if tampering has taken place in the lower mileage range up to 10,000 miles and in the higher mileage range up to 100,000. A continuous drive between the two highest order wheels can also be used to indicate tampering in the range below 10,000 miles.

Abstract: An indicating instrument for vehicles incorporating a piston which is so arranged that a slight movement causes a much larger displacement of a liquid level in a liquid column which is visible through a transparent housing of the instrument. In one embodiment the piston is movable in response to intake manifold pressure of an engine to indicate the efficiency of fuel utilization and in another embodiment, the piston is movable in response to a pendulum to indicate that the vehicle is either accelerating or decelerating.

Abstract: An underground conduit holder including a pair of identical conduit holding frames held together in spaced relationship by a pair of identical clamping structures. The clamping structures include latch portions which flex to facilitate easy attachment and detachment to holding frames without the requirement of special tools.

Abstract: A downrigger for use in controlling the depth in the water of a weight suspended from a boat and detachably carrying a fishing line to a desired fishing depth. The downrigger has a horizontally mounted reel driven through a selectively operable clutch device so that the trolling weight may be lowered by unreeling line or may be raised by winding the reel in the opposite direction. The downrigger may be positioned in selective positions on a boat and the line to the weight is fed through a deep grooved, swivelable pulley facilitating alignment of the trolling line and the downrigger for all of its selected positions. The trolling weight detachably holds the fishing line by a release mechanism which permits the angler to select the amount of pull required for the fishing line to release from the trolling weight.