Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-04-10
2003-11-11
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S594000, C029S606000, C029S828000, C029S855000, C029S856000, C324S207160, C324S207260, C324S236000, C324S237000, C264S272130, C264S272150, C264S272160, C264S272190, C264S328120, C425S125000, C425S145000, C425S146000, C425S147000
Reexamination Certificate
active
06643909
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a proximity probe and, in particular, to an encapsulated proximity probe and its manufacturing method for providing an accurate encapsulated proximity probe that is impervious to the predations of its environment and that is used to, inter alia, monitor vibration of rotating and reciprocating machinery.
BACKGROUND OF THE INVENTION
Proximity probe systems that analyze and monitor, for example, rotating and reciprocating machinery are known in the art. These systems typically include one or more proximity probes: noncontacting devices that measure displacement motion and position of the observed conductive target material relative to the probe. Typically, each proximity probe is located proximate a target object such as a rotating shaft of a machine or an outer race of a rolling element bearing being monitored and is connected to conditioning circuitry which in turn is coupled to analyzing apparatus for data reduction and display. By known techniques, these systems analyze and monitor rotating and reciprocating machinery for providing, inter alia, indications of incipient problems. A variety of proximity probe systems with a variety of different proximity probes are at the present time being sold by the assignee of this application, Bently Nevada Corporation of Minden, Nev.
In general, proximity probes are required to operate with precision under very adverse physical, chemical, and mechanical conditions and are often difficult to replace. Thus, there is an ongoing effort to make the proximity probe one of the most accurate and reliable parts of any proximity probe system.
The assignee's untiring commitment to improving proximity probes and the methods of manufacturing such probes for making the proximity probe one of the most accurate and reliable parts of any proximity probe system is chronicled in the seven patents to Van Den Berg (U.S. Pat. Nos.: 6,131,270; 6,131,267; 6,072,312; 5,818,224; 5,770,941; 5,712,562; and 5,685,884), the two patents to Schutts (U.S. Pat. Nos.: 5,021,737 and 5,016,343), and the single patent to Van Den Berg, et al. (U.S. Pat. No.: 5,351,388) all of which are hereby incorporated by reference in their entireties. However, it is stipulated that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the present invention as disclosed in greater detail hereinafter and as particularly claimed.
Hence, the assignee's patents as identified hereinabove reflect a line of proximity probes and the methods of manufacturing such probes. In their essence, these patents delineate a variety of different proximity probe tips, a variety of different bobbin or preform configurations, and how proximity probe manufacturing has evolved from the process of simply placing and epoxying a plastic insulating cap over a combined sensing coil, bobbin (or preform) and a fixed cable length assembly to an injection molding process of the coil, bobbin (or preform) and the fixed cable length assembly using radial and axial pin pulling techniques.
Heretofore, both the epoxying process and the injection molding process used to cover the sensing coil have been known to leave seams or interruptions that are susceptible to, inter alia, predations of the environment such as fluid and/or vapor ingress (e.g., oil, oil vapor, water, and/or water vapor) into the interior of the probe thereby causing probe deterioration leading to, inter alia, inaccurate and unreliable probe measurements.
For example, the pins employed in the radial and axial pin pulling process have been known to cause areas that fail to be filled in with moldable material during the encapsulation process such that an opening, slit, or the like is formed that allows fluid and/or vapor ingress into the interior of the probe thereby causing probe deterioration leading to, inter alia, inaccurate and unreliable probe measurements.
Furthermore, the radial and axial pin pulling processes are problematic in that the sensing coil, preform and fixed cable length assembly may become misaligned within the encapsulation thereby altering the desired spacing between a target object and the sensing coil of the probe such that inaccurate and unreliable measurements are obtained when in operation.
Specifically, it is critical that the displacement motion or position between the target object and the sensing coil of the proximity probe remains within the linear range of the proximity probe for providing accurate and reliable measurements over a wide range of circuit and environmental conditions in order to operate rotating and reciprocating machinery safely and efficiently. Thus, if the coil becomes skewed within the encapsulation the displacement motion or position between the target object and one area of the skewed coil will be different than the displacement motion or position between the target object and another area of the skewed coil thereby providing erroneous and undependable probe measurements when in operation. In fact, if the coil becomes skewed within the encapsulation the displacement motion or position between the target object and the sensing coil may completely fall out of the linear range of the proximity probe resulting in flawed probe measurements when in operation.
Moreover, a typical pin pulling process requires locating and aligning each of the coil and cable assemblies within a lower mold cavity via radial and axial pins, lowering or closing an upper mold cavity, injecting moldable material within the mold cavities, retracting the pins and further injecting moldable material within the mold cavities heretofore occupied by the retractable pins for fully encapsulating the coil and fixed cable length assembly. Hence, the pin pulling process requires that the molds be outfitted with precision retractable pins that are required to keep the coil and fixed cable length assembly located and aligned within the mold cavity during a first injection process. Then, the pins are timely retracted with precision such that the coil and cable assembly remains properly located and aligned within the mold cavity during a second injection molding process that fills the areas previously occupied by the retractable pins. Thus, this process not only requires a precision mold but also requires retractable pins to be movably disposed within the mold with precision. Additionally, this process requires pin actuators for moving the pins into and out of the mold cavity and supporting electronics that may require programming for orchestrating the timing of pin insertion and retraction. As a result, the pin pulling process relies on a multiplicity of components operating with precision and in synchrony for carrying out the two-step encapsulation process delineated in the prior art noted hereinabove.
For the foregoing reasons, there is a need for a proximity probe that is impervious to the predations of the environment and a method of manufacturing such a probe whereby the manufacturing problems and complexities of the prior art manufacturing processes are substantially eliminated.
Specifically, there is a need for a method of manufacturing proximity probes that can be repeatedly used to encapsulate sensing coils in a symmetrically manner (i.e., without the coils being skewed within the encapsulation). Additionally, there is a need for a method of manufacturing proximity probes that eliminates interruptions, openings, slits or the like that are formed within the encapsulation by internal parts such as sleeves covering the sensing element and/or by the encapsulation (injection molding) process itself. Furthermore, there is a need for a method of manufacturing proximity probes that eliminates the retractable pins, the pin actuators, and the supporting electronics associated with the prior art processes thereby eliminating the expense, unreliability and time consumption associated with these processes.
SUMMARY OF THE INVENTION
The present invention is distinguishable over the known prior art in a multiplicity of ways. F
Bently Nevada LLC
DeBoo Dennis A.
Kim Paul D
Vo Peter
LandOfFree
Method of making a proximity probe does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of making a proximity probe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of making a proximity probe will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3171473