Patent Application
20130031795
This invention was not made by an agency of the United States Government nor under a contract with an agency of the United States Government.
Not Applicable.
Not Applicable.
The Rod End Wear Detection Device (REWDD) is a fully portable, light weight apparatus designed for the measurement of bearing wear in two axes, including but not limited to, measurement of rod end bearing wear in both the radial and axial directions. REWDD is capable of taking measurements to one one-thousandths of an inch without the need to reorient or permanently modify the subject bearing.
A rod end bearing, also known as a heim joint or rose joint, is a mechanical articulating joint. Such joints are used on the ends of control rods, steering links, tie rods, or anywhere a precision articulating joint is required. In certain applications, such as aircraft, the rod end bearings must be monitored for signs of fatigue, wear or damage where failure of the equipment can have catastrophic consequences. Wear-indicating rod ends have been trialed in the past (document USAAMRDL-TR-76-14 Kaman Aerospace Corporation, Old Windsor Road, Bloomfield, Conn. 06002). A measuring pin is permanently trapped in a bushing which is welded in place in the bearing outer race. The pin is restricted from moving outward by a shoulder which contacts the welded bushing and from moving inward by contact with the spherical ball. The inner surface of the pin coincides with the inner surface of the bearing liner. The pin will be worn the same amount as the bearing liner. The top of the pin protrudes above the adjacent outer surface of the rod end bearing. The long axis of the pin coincides with the long axis of the rod end bearing, which is the axis of applied load and greatest wear.
At the time of manufacture the ball is loaded into intimate contact with its spherical seat on the side toward the pin. The protruding portion of the pin is machined off until the pin height above the adjacent surface is equal to or slightly less than the allowable internal clearance.
Prior inventions Apparatus for Measuring Wear of Rod End Bearings (U.S. Pat. No. 3,845,735) and Wear Measuring Arrangement for Bearings (U.S. Pat. No. 4,509,364) also describe apparatus for the measurement of bearing wear. However, none of the aforementioned inventions are capable of providing wear measurement in both the axial and radial directions without permanent modification to the rod end. As shown above, none of the prior inventions are able to provide accurate wear measurement without the requirement to permanently modify the subject bearing. Whereas the disclosed apparatus is light weight, portable and requires no modification to the bearing to provide accurate measurements of wear in two axis.
A potential patent classification for REWDD is Class 73 (Measuring and Testing), Subclass 7 (By Abrasion, Milling, Rubbing, or Scuffing). Class 73 includes processes and devices designed for measurement or testing of any kind. Subclass 7 includes those processes and devices designed for wear tests.
The Rod End Wear Detection Device (REWDD) is an apparatus designed for the measurement of bearing wear in two axes, including but not limited to, measurement of rod end bearing wear in both the radial and axial directions. The inner element of bearing is placed on an expanding mandrel and the external element clamped to hold the bearing perpendicular to the expanding mandrel, which is then secured to the internal indicator plate such that the relative movement between the fixed and moving elements of the bearing may then be measured.
An eccentric cam is utilized to operate the movement of a plate within the devise in either the axial or radial direction. The plate transfers the motion of the bearings free play to an indicator displaying the relative movement between internal and external elements of the bearing.
The Rod End Wear Detection Device (REWDD) is an apparatus designed for the measurement of bearing wear in two axes, including but not limited to, measurement of rod end bearing wear in both the radial and axial directions. A rod end bearing is a mechanical articulating joint used where a precision articulating joint is required, such as the ends of control rods, steering links, or tie rods. In certain applications, such as aircraft, the rod end bearings must be monitored for signs of fatigue, wear or damage where failure of the equipment can have catastrophic consequences.
The objectives of the invention are (1) the quantifiable detection of wear in a rod end or rolling element bearing, (2) the wear to be detected in a bearing in two orthogonal orientations, (3) the ability to quantifiably detect wear in a bearing in two directions without a requirement to permanently modify the bearing, (4) the ability to quantifiably detect wear in a bearing in two directions without a requirement to reorient the rod end, (5) to allow such quantifiable wear in both the axial and radial direction to be measured using a single indicator and (6) allow the use of the device on any rod end or rolling element bearing.
The disclosed apparatus allows measurements of wear in bearings to within one one-thousandth of an inch to be taken in the radial and axial directions. When employed for the measurement of rod ends, the apparatus is capable of taking measurements in confined spaces, without the requirement to completely remove the link from its installed position and without the need to reorient the rod end to facilitate both axial and radial measurements. By using the disclosed apparatus a user may ascertain the serviceability of a rod end by detecting the level of wear in the rod end bearing allowing timely replacement and/or repair.
The rod end bearing is placed on an expanding mandrel and the rod end shaft clamped using an appropriate clamping arrangement, including but not limited to a vee clamp or a flat clamp. The jaws of the clamping device are manufactured from engineering grade nylon or other appropriate material to alleviate any potential damage to the component being inspected. This also allows for interchangeability of the jaws providing suitable height adjustment for varying rod end designs and offsets.
Clamping the bearing in the foregoing manner causes the bearing to be held perpendicular to the expanding mandrel. The mandrel is then expanded into the bore of the bearing thus locking both the internal and external elements of the bearing. The expanding mandrel is then secured to the internal indicator plate such that the relative movement between the fixed and moving elements of the bearing may then be measured.
Individual axis locks (axial or radial) may then be released allowing relative motion between the internal and external elements of the bearing in a controlled manner by use of the appropriate actuator. Said actuators consist of an eccentric cam retained within the internal workings of the devise. These cams operate the movement of a plate within the devise in either the axial or radial direction.
The plate transfers the motion of the bearings free play to an indicator (or transducer and digital display) displaying the relative movement between internal and external elements of the bearing. The design of the plate is such that both axial and radial motions are transmitted to the indicator by the use of a precision machined angle on the plate and a corresponding contact on the indicator. Thus both axial and radial clearances of the subject bearing are able to be precisely measured without the need of additional indicators.
The configuration of the actuators and axis locks may also be adapted to suit specific needs. For example moving the locks and actuators from left to right or radial and axial moved from front to back.
Provisional Patent Application Number: 61/574,367 Filing Date: Aug. 2, 2011Relationship: Provisional application was for the same invention
| Number | Date | Country | |
|---|---|---|---|
| 61574367 | Aug 2011 | US |
