Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-04-26
2001-05-22
Hofsass, Jeffery (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S683000, C184S108000
Reexamination Certificate
active
06236328
ABSTRACT:
TECHNICAL FIELD
This invention relates a device for the monitoring of bearing performance in apparatus having one or more apertures sized and configured for grease fittings, as well as bearing housings which are specifically configured to enable monitoring of bearing performance. As used herein, the term bearings includes, but is not limited to, ball bearings, rotary bearings, and bushings.
BACKGROUND
U.S. Pat. No. 5,691,707 describes a device for monitoring bearing performance in apparatus having at least one aperture sized and disposed to connectably receive a grease fitting for providing lubricant to the bearing. The device comprises a sensing fitting sized and configured to be connectably received in the aperture. The sensing fitting can include temperature sensing means, vibration sensing means, or both, to enable detection of impending bearing failure.
While the fittings and related methods of use taught in U.S. Pat. No. 5,691,707 constitute an important advance in the art, they do not address concerns about exposure of the sensing means to weather or other harsh environmental conditions over time. Furthermore, integration of the fittings into an electronic monitoring system of commercial scale can prove difficult when sensing means signal strength is important.
A need thus continues to exist for devices which enable the monitoring of bearing performance while enduring harsh environmental conditions and producing strong signals useful in a commercially viable, integrated monitoring system.
SUMMARY OF THE INVENTION
The invention described herein is deemed to constitute such a contribution by providing, inter alia, a device for monitoring bearing performance in apparatus having at least one aperture sized and disposed to connectably receive a grease fitting for providing lubricant to the bearing. The device comprises a sensing fitting sized and configured to be connectably received in said aperture. The sensing fitting comprises a fitting body; at least one sensor; and at least one electronic component which is rigidly attached to the fitting body and electronically coupled to the sensor. The sensor is capable of (1) detecting change in temperature, (2) detecting vibration, or (3) detecting both vibration and a change in temperature, and the electronic component is configured to receive and amplify one or more signals from the sensor. The electronic component in devices of this invention is rigidly attached to the fitting body to provide ruggedness to the device, and to reduce the occurrence of interfering signal noise between the sensor and the electronics which amplify the sensor signals, thereby improving the quality of the amplified signal generated by the electronic component. This rigidity is preferably provided by embedding the electronic component and at least a portion of the fitting body in an encapsulating solid material which is non-conductive and thermally stable during use of the device and which provides water resistance to the electronic component(s) and sensor(s), as needed.
In one embodiment of the invention, the sensor is a combination of two devices which enable the sensor to detect vibration and change in temperature to enable detection of impending bearing failure. Thus, in this embodiment, impending bearing failure can be sensed by either or both of two indicators of impending bearing failure—an increase in temperature and an increase in vibration. In another embodiment, the sensor is capable of detecting change in temperature alone, while in yet another embodiment, the sensor is capable of detecting vibration alone. All such systems are effective for early detection of the inception of bearing failure.
In preferred embodiments including a temperature sensor, the temperature sensor more preferably further comprises either (i) a thermistor temperature detector, which undergoes a change in resistance in response to a change in temperature within the apparatus, or (ii) a thermocouple sensing element, which undergoes a change in current in response to a change in temperature within the apparatus. It is particularly preferred that the electronic component be adapted to send its amplified signal to a receiver capable of converting the amplified signal into an audible or visual record of the temperature within the apparatus and/or producing an audible or visual alarm if the temperature reaches a preselected level. It is also particularly preferred that the electronic component be adapted to constantly send the amplified signal, and that the receiver be capable of trending the data produced by conversion of that signal to provide trended data regarding temperature levels and impending bearing failure.
In preferred embodiments including a vibration sensor, the vibration sensor is preferably capable of detecting vibration within an x, y and/or z plane. It is particularly preferred that the electronic component be adapted to send its amplified signal to a receiver capable of converting the amplified signal into an audible or visual record of the vibration within the apparatus and/or producing an audible or visual alarm if the vibration reaches a preselected level. It is also particularly preferred that the vibration sensor be adapted to constantly send the amplified signal, and that the receiver be capable of trending the data produced by conversion of that signal to provide information regarding vibration levels and impending bearing failure.
In another embodiment of this invention, the sensing fitting is in addition a grease fitting for providing lubricant to said bearing. Here it is particularly preferred that the sensing fitting have an axial bore throughout and be configured on one end (at a connecting end portion) to be detachably yet fixedly inserted into an aperture sized and configured to receive a grease fitting. As used herein, “axial” is deemed to mean parallel to the longitudinal axis of the device, but not necessarily coaxial therewith. The other end of the sensing fitting opposite the connecting end portion is configured to function as a grease fitting through which lubricant may be injected into the apparatus via the axial bore. Thus, in this embodiment, the grease fitting is integral to the sensing fitting, and the device may be substituted for a conventional grease fitting to permit monitoring of bearing performance and to enable detection of impending bearing failure, without sacrificing the utility of a conventional grease fitting.
In another particularly preferred embodiment, the sensing fitting is separate from, but employed in conjunction with, a grease fitting. In this embodiment, the sensing fitting is configured, at its connecting end portion, to be detachably yet fixedly inserted into an aperture of the apparatus containing the bearing, the aperture being sized and configured to receive a grease fitting. The sensing fitting has an axial bore throughout which is stepped, if necessary, so that the portion of the bore proximate to the other end of the fitting, the receiving end portion, opposite the connecting end portion is sized and configured to provide an aperture for the detachable yet fixed attachment of a grease fitting. In this particularly preferred embodiment, the sensing fitting provides an intermediate connection between the grease fitting and the apparatus containing the bearing. The fitting thereby acts as a supplement to a grease fitting to permit monitoring of bearing performance and to enable detection of impending bearing failure, without sacrificing the utility of a grease fitting.
This invention also provides a bearing housing comprised of a housing body which defines a cavity, a fitting body which is attached to said housing body and which defines a grease path in communication with the cavity, a sensor, and an electronic component which is rigidly attached to said fitting body and coupled to said sensor, wherein said sensor is capable of (1) detecting change in temperature, (2) detecting vibration, or (3) detecting both vibration and a change in temperature, said electronic component being configured to receive and
Davies, Jr. William F.
Smith Charles C.
Smith Eric C.
Hofsass Jeffery
Pham Toan
Scientific Operating Systems, Inc.
Sieberth & Patty L.L.C.
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