Machine element or mechanism – Mechanical movements – Rotary to intermittent unidirectional motion
Patent
1996-03-11
1999-01-19
Marmor, Charles A.
Machine element or mechanism
Mechanical movements
Rotary to intermittent unidirectional motion
74122, F16H 346, F16H 2908
Patent
active
058603204
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a variable ratio power transmission and relates particularly, though not exclusively, to a gear box in which the gear ratio of the input and output shafts can be varied continuously between a maximum and a minimum.
BACKGROUND TO THE INVENTION
Fundamentally the function of a gear box is to change the speed from that of an input shaft to that of an output shaft whilst allowing the transmission of torque between the shafts. Typically gear boxes comprise several gear clusters or gear trains that can be coupled to each other in various configurations to give selected gear ratios of the input and output shafts.
One of the disadvantages of most conventional gear boxes is that the gear ratios that can be selected are fixed at certain preselected ratios that may or may not be optimum to derive maximum torque from the engine or other drive source. In motor vehicles it is desirable to maintain the internal combustion engine at an optimum speed, both from the point of view of fuel economy and to obtain maximum torque. Likewise, it is preferable to maintain the speed of certain types of electric motors within a prescribed RPM range in order to develop maximum torque efficiency. However this is not possible with a conventional gearbox and a compromise is made using preselected gear ratios.
Another disadvantage of most conventional gear boxes is that they are generally bulky and occupy a considerable volume in the drive train. A still further disadvantage of most conventional gear boxes is that the load must be disconnected when changing gears and when starting the engine or motor driving the load.
The present invention was developed with a view to providing a variable ratio power transmission that is able to overcome one or more of the above-noted disadvantages of the prior art.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a variable ratio power transmission comprising:
a first element rotatably mounted in connection with a first structure on a first axis, said first structure being pivotable about said first axis and being coupled to said first element via a first one-way coupling means, wherein pivoting movement of the first structure in a first direction about said first axis results in a torque being applied via the first one-way coupling means to the first element whereas pivoting movement of the first structure in the opposite direction has no effect via the first one-way coupling means on the rotation of the first element; and,
an actuating means which is mechanically coupled to said first structure, and wherein relative movement of said actuating means and said first structure about a second axis which is substantially perpendicular to said first axis produces an oscillating pivoting movement of said first structure about said first axis, and wherein means for varying the angle through which said first structure pivots is provided whereby, in use, an output torque transmitted via the first element can be varied independently of an input torque applied to the power transmission.
Preferably said first structure is one of a plurality of pivotable structures, each pivotable structure having one or more elements rotatably mounted in connection therewith on a respective axis, each said pivotable structure being pivotable about said respective axis and being coupled to said one or more elements by one or more one-way coupling means respectively.
In one embodiment said actuating member is rotatable about said second axis and is mechanically coupled to said first structure via a variable rotational coupling, and wherein the radius of orbit of said variable rotational coupling can be varied to vary the angle through which said first structure pivots.
Typically the radius of orbit of said rotational coupling can vary between zero, which results in the first structure remaining substantially stationary and no torque being transmitted to the first element, and a maximum value which results in a maximum torque being t
REFERENCES:
patent: 2636395 (1953-04-01), Salomon
patent: 2677968 (1954-05-01), Hubner
patent: 4336870 (1982-06-01), Shea
patent: 5269193 (1993-12-01), Rabinow
Fenstermacher David
Marmor Charles A.
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