Optical position sensing and method
First Claim
1. An improved optical position sensing device for a variable displacement type hydraulic pump/motor assembly including one of an angularly movable yoke and an angularly movable swashplate, an optical/electronic sensor unit capable of reading indicia markings, for sensing the movement of at least one of said yoke, said swashplate and means for moving said swashplate, relative to a reference location in a stationary housing of said pump/motor assembly,.said one of said yoke, said swashplate and said means for moving said swashplate, being provided with a plurality of absolute scale indicia markings, wherein said improvement comprises:
- a. said absolute scale indicia markings being in the form of a bar-type pattern and being located on a surface of one of said angularly movable yoke, said swashplate and said means for moving said swashplate; and
b. said optical/electronic sensor unit being fixedly located on said stationary housing and including an optical read head sealingly extending into the interior of said housing and being located at a predetermined, spaced distance from said indicia markings for sensing said indicia markings and producing an optical signal.
2 Assignments
0 Petitions
Accused Products
Abstract
In a variable displacement type hydraulic pump/motor assembly including at least one internally movable component, such as a yoke, a swashplate, and the means for moving the swashplate, the improvement includes imparting on this component absolute location indicia markings and the addition of an optical/electronic sensor unit capable of reading such indicia markings fixedly located on a housing of the pump/motor assembly and including an optical read head extending into the housing interior and located at a spaced distance from the indicia markings for reading same, relative to a reference location, and producing a signal indicative of the absolute position of the movable component. The signal can then, in turn, be used for controlling the displacement of the pump/motor assembly. A method for determining the absolute component position is also set forth.
30 Citations
46 Claims
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1. An improved optical position sensing device for a variable displacement type hydraulic pump/motor assembly including one of an angularly movable yoke and an angularly movable swashplate, an optical/electronic sensor unit capable of reading indicia markings, for sensing the movement of at least one of said yoke, said swashplate and means for moving said swashplate, relative to a reference location in a stationary housing of said pump/motor assembly,.said one of said yoke, said swashplate and said means for moving said swashplate, being provided with a plurality of absolute scale indicia markings, wherein said improvement comprises:
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a. said absolute scale indicia markings being in the form of a bar-type pattern and being located on a surface of one of said angularly movable yoke, said swashplate and said means for moving said swashplate; and
b. said optical/electronic sensor unit being fixedly located on said stationary housing and including an optical read head sealingly extending into the interior of said housing and being located at a predetermined, spaced distance from said indicia markings for sensing said indicia markings and producing an optical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for sensing the absolute position of an angularly movable swashplate/yoke in a variable displacement type hydraulic pump/motor assembly, said assembly including:
- said angularly movable swashplate/yoke;
means for moving said swashplate/yoke;
an optical electronic sensor unit capable of reading indicia markings for sensing the movement of at least one of said swashplate/yoke and said means for moving said swashplate/yoke relative to a reference location in a stationary housing containing said pump/motor assembly, said method including the steps of;
a. providing one of said swashplate/yoke and said means for moving said swashplate/yoke with absolute indicia markings;
b. forming said indicia markings in a bar-type pattern and locating same in a surface of one of said swashplate/yoke and said means for moving said swashplate/yoke;
c. fixedly locating said optical/electronic sensor on said stationary housing;
d. extending an optical read head, associated with said optical/electronic sensor, into the interior of said housing at a predetermined, spaced distance from said indicia markings; and
e. sensing said indicia markings and producing an optical signal indicative of the absolute position of said at least one of said swashplate/yoke and said means for moving said swashplate/yoke. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37)
- said angularly movable swashplate/yoke;
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38. An optical position sensing device in combination with a variable displacement type hydraulic pump/motor assembly including one of an angularly movable yoke and an angularly movable swashplate, and means for moving said swashplate, wherein the improvement comprises the addition of:
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a. absolute indicia markings, in the form of a bar-type pattern, on a surface of one of said yoke, said swashplate, and said means for moving said swashplate; and
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b. an optical/electronic sensor unit capable of reading said indicia markings fixedly located on a stationary housing of said pump/motor assembly and including an optical read head extending into the interior of said housing and being located at a predetermined, spaced distance from said indicia markings for sensing said indicia markings relative to a reference location in said stationary housing and producing an optical signal indicative of the absolute position of at least one of said yoke, said swashplate, and said means for moving said swashplate. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46)
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Specification