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Flexible sensor input assemblyFlexible sensor input assembly description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070182404, Flexible sensor input assembly. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND [0001] The present invention relates to a device for measuring oscillatory or rotational angular displacement of one component in a machine relative to another component, the second component being stationary, oscillating, or rotating at a different rate and/or direction with respect to the first component. [0002] In a machine with moving parts, oftentimes a component in the machine moves, rotates, or oscillates at a different rate than another component in the same machine. It is often desirable to measure the oscillatory or rotational angular displacement between the two components. A device can be installed between two parts of a machine to measure this displacement. The device has two ends; a first end coupled to a moving component of a machine and a second end coupled to a moving or stationary component of a machine that includes a portion of a measurement system to measure oscillation or rotational angular displacement of the first moving component. The two ends are connected to one another by a rigid member. In many cases, the measurement device is installed after the machine has been assembled and can be coupled to pre-existing attachment fixtures on the machine. Because the measurement device is typically installed after assembly of the machine, the attachment fixtures should be aligned such that the measurement device fits correctly within the machine. However, if tolerances of the machine parts or the attachment fixtures are such that proper alignment does not exist, the measurement device either cannot be installed, or if installation is possible, accurate and reliable measurement of the movement of a moving component with respect to another component is compromised, or the assembly is bent or fractured. SUMMARY [0003] The device of the present invention achieves accurate and reliable determination of the oscillatory or rotational angular displacement of a first component in a machine with respect to another component in the machine. The device is able to be installed between two components of a machine even if the pre-existing attachment fixtures or locations are misaligned. [0004] In one embodiment, the invention provides a sensor assembly for determining rotational angular displacement of a first moving component in a machine relative to a second component in the machine. The sensor assembly includes a base, a magnet housing, and a flexible member. The base is configured to be rigidly secured to the first moving component for movement therewith. The base defines a first axis of rotation. The magnet housing supports a sensor magnet and is rotatably received in the second component. The magnet housing defines a second axis of rotation. The flexible member has a first end rigidly secured to the magnet housing coaxially with the first axis of rotation. A second end of the flexible member is rigidly secured to the magnet housing coaxially with the second axis of rotation. A flexible body portion of the flexible member is capable of accommodating misalignment between the first and second axes of rotation. [0005] In another embodiment the invention provides an assembly including a stationary housing, a swashplate movable relative to the stationary housing, and a sensor assembly for determining rotational angular displacement of the swashplate relative to the stationary housing. The sensor assembly includes a base rigidly secured to the swashplate for movement therewith. The base defines a first axis of rotation. A magnet housing supporting a sensor magnet and being rotatably received in the stationary housing. The magnet housing defines a second axis of rotation. A flexible member has a first end rigidly secured to the base coaxially with the first axis of rotation, a second end rigidly secured to the magnet housing coaxially with the second axis of rotation, and a flexible body portion capable of accommodating misalignment between the first and second axes of rotation. [0006] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 is a perspective view of a measurement device of the present invention located in a portion of a machine whose components are to be measured. [0008] FIG. 2 is a perspective view of the measurement device shown in FIG. 1. [0009] FIG. 3 is a partial cross-section view of the measurement device of FIG. 2. [0010] FIG. 4 is an exploded view of the machine and measurement device shown in FIG. 1. DETAILED DESCRIPTION [0011] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings. [0012] FIG. 1 illustrates a portion of a pump, compressor, or other machine 10 having a first movable component 14 and a second stationary or movable component 18. In the illustrated embodiment, the machine is a variable displacement pump having a swashplate assembly 22. The swashplate assembly 22 includes a swashplate 26 coupled to at least one inner race member 30. Each inner race member 30 is positioned adjacent a respective outer race member 34. Rolling elements (not shown) are located between each inner race member 30 and outer race member 34 to allow the inner race member 30 to move with respect to the outer race member 34. The outer race member 34 is coupled to a bearing saddle, or cradle, 38 that is stationary. The swashplate assembly 22 also has a radially centered opening 42 for passage of a rotatable shaft (not shown). In operation, the swashplate 26 oscillates back and forth in the cradle 38 about an axis 46. The illustrated swashplate 26 can oscillate in the cradle 38 to each side of the axis 46 by about 20 to 25 degrees, however, the oscillation angle can vary as desired. The swashplate 26 is driving or being driven by pistons (not shown) reciprocating in a rotating cylinder block (not shown) of a fluid machine, as is understood to those skilled in the art. [0013] In the illustrated embodiment, the second stationary or movable component 18 is a stationary wall 50. The stationary wall 50 includes a bore 54 extending partially or entirely through the stationary wall 50. The bore defines an axis 48 (see FIG. 4). A sensor (not shown) is attached to the stationary wall 50 to communicate with the bore 54, and is operable to send signals to a processor, as will be described in more detail below. [0014] FIG. 1 also illustrates a measurement device, or flexible sensor input assembly 58 of the present invention. The flexible sensor input assembly 58 includes a base 60, a sensor magnet housing 64, and a flexible axial connecting member, or flexible member 68 interconnecting the base 60 and the sensor magnet housing 64. As illustrated in FIGS. 2 and 3, the base 60 of the flexible sensor input assembly 58 includes a body portion 72, that in the illustrated embodiment has a generally plate-like configuration, and a projecting portion 76, that in the illustrated embodiment has a generally cylindrical configuration. The body portion 72 includes an aperture 80 extending therethrough to facilitate mounting the body portion 72 to the swashplate 26 with a fastener 84 (e.g., a screw--see FIGS. 1 and 2), as will be described below. A protrusion 88 extends from the body portion 72 adjacent the aperture 80 for aligning the body portion 72 with respect to the swashplate assembly 22 during installation. [0015] The projecting portion 76 is sized and configured to be received in a receiving aperture 92 (see FIG. 4) in the swashplate assembly 22. The receiving aperture 92 is substantially coaxial with the axis 46 about which the swashplate 26 oscillates so that oscillation of the swashplate 26 causes rotation of the projecting portion 76 of the base 60 about the axis 46 when the projecting portion 76 is received in the aperture 92. As shown in FIG. 3, the projecting portion 76 also defines a receiving aperture 96 for receiving one end 100 of the flexible member 68. The receiving aperture 96 has a beveled end 104 that aids in locating the end 100 of the flexible member 68 axially. In other embodiments, the aperture 96 can have an alternative end geometry such as rounded, ovoid, cylindrical, conical, or the like. [0016] The base 60 is made of a suitable polymer or a metallic material. In the illustrated embodiment, the base 60 is a polymer that is molded about the flexible member 68. In other embodiments, the base 60 can be mechanically fixed to the flexible member 68 by any suitable means. [0017] With continued reference to FIG. 3, the sensor magnet housing 64 includes an aperture 108 for receiving the second end 112 of the flexible member 68. The sensor magnet housing 64 can be crimped or otherwise mechanically deformed to retain the second end 112 of the flexible member 68. Other mechanical securing means can also be employed. [0018] The sensor magnet housing 64 also includes a bore 116 that receives and supports a sensor magnet 120. In the illustrated embodiment, the sensor magnet 120 is molded into the bore 116 in the sensor magnet housing 64. The sensor magnet 120 is magnetized after final and complete assembly of the flexible sensor input assembly 58. Magnetization after final and complete assembly of the flexible sensor input assembly 58 establishes a closed polar magnetic field in a fixed angular relation to the base 60, and eliminates angular inaccuracies due to a tolerance stack-ups. The tolerance stack-ups can occur if the sensor magnet 120 was magnetized prior to assembly into the sensor magnet housing 64, or if the magnetization occurred prior to final and complete assembly of the flexible sensor input assembly 58. The sensor magnet housing 64 can be ferrous, or of any other composition such that the sensor magnet housing 64 aids in the formation of a closed polar magnetic field of sufficient strength to allow accurate measurement of minute angular displacements. An O-ring 124 around the outer circumference of the sensor magnet housing 64 helps to create a seal between the sensor magnet housing 64 and the bore 54 of the stationary wall 50 into which the sensor magnet housing 64 is inserted. [0019] The sensor magnet housing 64 incorporates axial and radial features to provide permanent axial retention and rotational registration of the sensor magnet 120 relative to the sensor magnet housing 64 and the base 60. For example, as shown in FIG. 3, a circumferential groove 128 in the bore 116 of the magnet housing 64 helps to retain and register the sensor magnet 120 with respect to the sensor magnet housing 64. The crimped connection between the sensor magnet housing 64 and the flexible member 68 maintains the relative position of the flexible member 68 in relation to the sensor magnet housing 64 and the sensor magnet 120. [0020] The flexible member 68 can be made of any strong flexible material such as a polymer, a woven metallic material, or a braided metallic material. As mentioned above, the material of the flexible member 68 can be chosen to facilitate molding the base 60 around the flexible member 68. Due to the fixed mechanical connection with each of the base 60 and the sensor magnet housing 64, the flexible member 68 transmits the rotation of the projecting portion 76 caused by oscillation of the swashplate assembly 22 to the sensor magnet housing 64. Rotation of the sensor magnet housing 64 is sensed by the sensor attached to the stationary wall 50, and a signal indicative of the angular position of the swashplate assembly 22 can be relayed to the processor. Continue reading about Flexible sensor input assembly... Full patent description for Flexible sensor input assembly Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Flexible sensor input assembly patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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