Measuring and testing – Dynamometers – Responsive to torque
Reexamination Certificate
1999-11-23
2001-02-06
Noori, Max (Department: 2855)
Measuring and testing
Dynamometers
Responsive to torque
Reexamination Certificate
active
06182516
ABSTRACT:
TECHNICAL FIELD
This invention relates to a dynamometer that measures force imparted by a disk brake to a disk attached to the shaft of an engine.
BACKGROUND ART
As is known, dynamometers are devices which load engines while running, in order to determine information about the engines, such as torque as a function of speed. Dynamometers which use dual rollers driven by wheels of a vehicle are extremely complex and expensive. Even dynamometers heretofore available for small engines, which connect an axle to the shaft of the engine independently of the vehicle, cost more than several thousand dollars.
DISCLOSURE OF INVENTION
Objects of the invention include provision of an engine dynamometer which is capable of being manufactured at very low cost, which is uncomplicated and very easy to use, and which may provide readings which are direct (e.g., a gauge) or electronic (capable of being fed directly into electronic processing apparatus, such as a personal computer).
According to the present invention, a disk mounted to a shaft driven by an engine, the torque of which is to be measured, is loaded by a disk brake mounted on a brake support. Tangential counterforce applied to the disk brake as a result of applying a braking force to the disk is measured by a force transducer, such as a conventional electronic force transducer which provides a signal proportional to force, a conventional force gauge, a distance or position measurement, or a measurement of strain. The brake support may be a pendulum which is journaled on a shaft that is coaxial with, but independent of, the motor shaft; or it may be on a pendulum journaled on the motor shaft; or it may be a member slidable in a directional coaxial with the counterforce; or it may be a flexure member, in which case, instead of a force transducer, the readout mechanism might be a position sensor or a strain gauge. In one embodiment, the disk brake comprises a caliper having disk brake pads on both sides and actuated by means of hydraulic or pneumatic pressure provided by a manual pump; clamp brakes may be used instead.
The invention may be used, as in the exemplary embodiment herein, on internal combustion engines of the type useful in racing go-carts, which may be on the order of five horsepower, or may be used in high RPM fractional horsepower motors, such as in model airplanes and remote control dune buggies and the like, or it may be used on larger engines, including quarter midget racing engines in the 20 horsepower to 30 horsepower range, or full-sized engines, provided that the brake pads and the bottom of the disk may require immersion in water or other cooling. The invention may also be used on other engines and motors, including electric motors. The precepts of the invention can be expanded utilizing much larger components for engines and motors of any sort. As used herein, the term “engine” means any type of engine or motor that produces rotary mechanical power. The invention may be utilized by being connected directly to the output shaft of an engine, as in the exemplary embodiments herein, may be connected to the output shaft of a clutch or of a transmission, may be connected to a wheel turning shaft, such as an axle, or any other shaft driven by an engine.
The disk brake may be a hydraulically actuated, caliper disk brake as disclosed in the exemplary embodiment, or it may be a clamp brake, or it may be a cam actuated brake (of the type used in early model snowmobiles) or any other form of brake which is easily controlled by the operator. It is one of the advantages of the invention that the amount of pressure applied by the brake to the disk is irrelevant; all that needs to be known is the force exerted by the brake on the disk, which is equal to the measured counterforce, and the distance from the center of rotation of the disk to the point where the force is measured, whereby to indicate torque. These may all be measured more or less directly or indirectly (such as strain as a function of force).
The invention need not measure the torque extremely accurately, and it should be understood that the measurement of torque herein is deemed to include a substantial measurement of the torque (that is, measuring approximately the torque), since what is of interest is how an engine behaves one day compared with the next, or what effect a particular change in engine adjustments has on the engine, and the like.
The invention may be utilized with conventional tachometers to provide torque versus speed measurements, at a variety of engine speeds. Multiple brakes may be used, if desired.
Other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of exemplary embodiments thereof, as illustrated in the accompanying drawing.
REFERENCES:
patent: 3610342 (1971-10-01), Stainken
patent: 4412455 (1983-11-01), Borgersen
patent: 4685745 (1987-08-01), Reinecke
patent: 4833938 (1989-05-01), Reinwall et al.
patent: 5003829 (1991-04-01), DeConti et al.
Noori Max
Williams M. P.
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