Combination monitoring device and patch for a pneumatic tire and method of installing the same with a coupled antenna

Abstract: A monitoring device (31) and patch (16) combination used to monitor the conditions of a pneumatic tire having an innerliner includes a monitoring device and a patch. The monitoring device includes at least one sensing element (18) that is adapted to sense a condition of the pneumatic tire. The monitoring device also includes a first electrical pad (26) connected to the sensing element. The monitoring device and first electrical pad are preferably encapsulated in an encapsulation material. The patch (16) is adapted to carry the monitoring device and mount the monitoring device on the innerliner of the tire. An antenna (34) is embedded within the patch and a second electrical pad (36) is connected to the antenna. The monitoring device is disposed on the patch in a manner such that the first and second electrical pads are aligned to provide electrical coupling between the pads. The antenna is in communication with the sensing element through the electrical coupling between the pads. The monitoring device and patch may be manufactured in separate facilities and then brought together when they are connected to the innerliner of the tire without the requirement of a physical connection between the sensing element and the antenna.

Description: BACKGROUND OF THE INVENTION Technical Field The present invention generally relates to monitoring devices used to monitor the conditions of a pneumatic tire and, more particularly, to a monitoring device and patch combination with the antenna of the monitoring device disposed in the patch and being electrically coupled to the monitoring device when the combination is assembled. Specifically, the present invention relates to an encapsulated monitoring device having a first electrical pad that is aligned with a second electrical pad in a patch wherein the connection between an antenna in the patch and the monitoring device is established by electrical coupling between the aligned electrical pads. Background Information It is often desired in the art to monitor the conditions of a tire while it is installed and in use on a vehicle. Typical desirable measurements are tire wear, internal temperature, and internal pressure. These measurements are preferably taken while the tire is in use on the vehicle without having to remove the tire from the vehicle or specifically position the tire to take the measurement. Numerous types of monitoring devices are known in the art to perform these measurements. One type of monitoring device uses a passive integrated circuit embedded within the body of the tire that is activated by a radio frequency transmission that energizes the circuit by inductive magnetic coupling. Other prior art devices used for monitoring tire conditions include self-powered circuits that are positioned external of the tire, such as at the valve stem. Other active self-powered programmable electronic devices are disclosed in U.S. Patents 5,573,610, 5,562,787, and 5,573,611 which are assigned to the assignee of the present application. Each of the active self-powered programmable electronic devices includes an antenna that is used to transmit the data created by the monitoring device to the data gathering device positioned outside of the tire. One of the problems in the art is to position the antenna such that the data created by the monitoring device is accurately transmitted to the data gathering device outside of the tire. It is desired to position the antenna as close to the outside of the pneumatic tire as possible so that the transmissions pass through as little of the tire as possible. In the past, the antenna of the monitoring device generally extended into the interior chamber of the tire such that the radio waves had to pass first through the air inside the tire, through the innerliner, through the tire sidewall, and then through the air to the data gathering device. It is desired in the art to provide an antenna for an active, self-powered programmable electronic device that is positioned so that the radio waves do not have to first pass through the inner chamber of the tire before entering the tire sidewall. The bead ring and apex filler of the tire tend to block the radio transmission from the monitoring device. It is thus desired in the art to position the antenna away from the bead ring and apex filler so that the transmission through the tire sidewall is as strong as possible. On the other hand, it is also desirable to position the monitoring device as close to the bead ring as possible because that area of the tire sidewall experiences fewer forces and stretching than the middle portion of the tire sidewall. It is thus desired in the art to provide a method for attaching the antenna to the monitoring device that accommodates the ideal position for both elements. The monitoring devices known in the art are typically encapsulated with an encapsulation material that provides structural support to the monitoring device so that the device is not destroyed by the forces normally encountered and experienced by a pneumatic tire. In some applications, the process of encapsulation will take into account that the antenna must extend from the encapsulated monitoring device. It is desired to provide a monitoring device configuration that eliminates this encapsulation problem by positioning the antenna apart from the monitoring device. One method of connecting the monitoring device to the innerliner of a tire includes the use of a rubber attachment patch to carry the monitoring device with the inner surface of the rubber patch being configured to securely adhere to the innerliner of a tire. It is desired that the sensitive electronic monitoring device and the rubber patch be capable of being manufactured in separate locations and assembled when the monitoring device is attached to the innerliner of a tire. Separating the rubber attachment patch and the sensitive monitoring device also allows the rubber attachment patch to be aggressively attached to the innerliner of a tire without the risk of damaging the sensitive monitoring device. After the rubber attachment patch is securely anchored to the innerliner, the monitoring device may be attached to the patch. SUMMARY OF THE INVENTION In view of the foregoing, it is an objective of the present invention to provide a monitoring device and patch combination that does not require a physical connection between the antenna and the monitoring device. This and other objectives and advantages of the present invention are obtained by a monitoring device and patch combination used to monitor the conditions of a pneumatic tire having an innerliner, the combination comprising the features of claim 1. BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the invention, illustrative of the best mode in which the applicants contemplate applying the principles of the invention, are set forth in the following description and are shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims. FIG. 1 is a partial sectional view of a pneumatic tire with the monitoring device and patch combination connected to the innerliner of the pneumatic tire; FIG. 2 is a sectional side view of a monitoring device and patch combination; FIG. 3 is a sectional end view of the monitoring device and patch combination showing the alignment of the first electrical pad with the second electrical pad; FIG. 4 is a sectional view taken along line 4-4, FIG. 3; FIG. 5 is a fragmentary sectional view taken along line 5-5, FIG. 3 showing a portion of the encapsulated monitoring device in section and a portion of the patch in section; FIG. 6 is a sectional view similar to FIG. 1 showing an embodiment of the present invention; FIG. 7 is a sectional view similar to FIG. 6 showing the attachment of the monitoring device to the innerliner of a tire of the present invention; and FIG. 8 is a sectional view similar to FIGS. 6 and 7 showing a second different than that of the present invention. Similar numerals refer to similar parts throughout the drawings. DESCRIPTION OF THE PREFERRED EMBODIMENT A monitoring device and patch combination, not forming part of the present invention is depicted in FIGS. 1-5 and is indicated generally by the numeral 10. Combination 10 is connected to an innerliner 12 of a pneumatic tire 8 as shown in FIG. 1. Combination 10 preferably is connected to innerliner 12 by an attachment that is known in the art, such as a suitable adhesive. Combination 10 includes a monitoring device 14 and an attachment patch 16 that are fabricated separately. Monitoring device 14 includes at least one sensing element 18 that is configured and adapted to read at least one desired parameter or sense at least one desired engineering condition of pneumatic tire 8. Monitoring device 14 further includes a power source or battery 24 that supplies power to monitoring device 14. In addition to the devices discussed above, other examples of monitoring devices are shown in U.S. Patent No. 5,573,610, the contents of which are incorporated herein by reference. Sensing element 18 is connected to a first electrical pad 26 by a suitable connector 28 such as a wire. Electrical pad 26 may be spaced from monitoring device 14 or may be an integral element of monitoring device 14. Monitoring device 14 and first electrical pad 26 are preferably encapsulated by an encapsulation material 30 that serves to protect monitoring device 14. Encapsulation material 30 may be a suitable epoxy or plastic that provides a rigid structure around monitoring device 14 and electrical pad 26. Encapsulation material 30 forms an encapsulated monitoring device 31 that includes a bottom surface 32 that provides a mounting surface for encapsulated monitoring device 31. Bottom surface 32 has at least one portion that is substantially planar. First electrical pad 26 is substantially parallel to the planar portion of bottom surface 32 and is also adjacent to bottom surface 32, but is still completely surrounded by encapsulation material 30. Patch 16 includes an antenna 34 embedded within the body of the patch. A second electrical pad 36 is connected to antenna 34 and is also embedded within patch 16. Patch 16 may be formed from a suitable rubber or combination of rubbers that are compatible with and provide desirable adhesion properties with innerliner 12. Patch 16 has a top surface 38 sized and adapted to receive encapsulated monitoring device 31 such that bottom surface 32 lies against top surface 38 when encapsulated monitoring device 31 is connected to patch 16. Second electrical pad 36 is adjacent to top surface 38 but spaced therefrom by the material of patch 16. Second electrical pad 36 may be integrally formed with antenna 34 and, in some embodiments of the invention, may simply be a portion of antenna 34 disposed where it may electrically couple through the material of patch 16. Antenna 34 may be any of a variety of suitable antennas such as a wire, a bar, a plate, or the like. Patch 16 includes a foot portion 35 that extends away from top surface 38. Antenna 34 is embedded within foot portion 35 such that it is positioned away from encapsulated monitoring device 31. Foot portion 35 of patch 16 allows encapsulated monitoring device 31 to be positioned closer to the bead ring 37 and apex filler 39 of tire 8 than antenna 34. Such positioning allows the signals from antenna 34 to propagate around bead ring 37 and apex filler 39. First electrical pad 26 is aligned with second electrical pad 36 when encapsulated monitoring device 31 is mounted on patch 16. Although first and second electrical pads 26 and 36 are aligned, they remain spaced from each other by the intervening material of patch 16 and encapsulation material 30. Electrical pads 26 and 36 are close enough, however, to create an electrical coupling such that sensing element 18 is in communication with antenna 34. Such electrical coupling is known to those skilled in the art and allows a signal to be communicated between pads 26 and 36. Such alignment and spacing is in accordance with another objective of the present invention that allows encapsulated monitoring device 31 to be installed on patch 16 without requiring a direct physical electrical connection between antenna 34 and monitoring device 14. Monitoring device 14 and patch 16 may be connected to innerliner 12 in the following manner. First, monitoring device 14 is provided with sensing element 18, first electrical pad 26, and connector 28. Monitoring device 14 is then encapsulated with encapsulation material 30 to entirely encapsulate monitoring device 14 and first electrical pad 26. Patch 16 is then fabricated with antenna 34 embedded within the body of patch 16. Antenna 34 is connected to second electrical pad 36 that is also embedded within the body of patch 16. The steps of fabricating device 31 and patch 16 may be performed at separate locations because no physical connection between antenna 34 and device 31 is required. Pneumatic tire 8 is then selected having innerliner 12 where combination 10 is installed. Encapsulated monitoring device 31 first may be connected to patch 16 by aligning first electrical pad 26 with second electrical pad 36. Encapsulated monitoring device 31 is then connected to patch 16 by seating bottom surface 32 of encapsulated monitoring device 31 onto top surface 38 of patch 16. A suitable manner of connecting the two elements is used such as a suitable adhesive. Device 31 and patch 16 are then connected to innerliner 12 by a suitable connector such as an adhesive. The connection of combination 10 to innerliner 12 thus does not require a direct physical electrical connection between antenna 34 and monitoring device 14. The alignment of electrical pads 26 and 36 and the resulting electrical coupling provides the necessary communication between antenna 34 and monitoring device 14. Combination 10 may also be installed on pneumatic tire 8 by first connecting patch 16 to innerliner 12. Patch 16 may be aggressively stitched to innerliner 12 without the danger of damaging monitoring device 14 because monitoring device 14 is later connected to patch 16. After patch 16 is suitably connected to innerliner 12, monitoring device 14 is aligned with patch 16 as discussed above and connected by a suitable connector such as an adhesive. The communication between antenna 34 and monitoring device 14 is automatically created when electrical pads 26 and 36 are properly aligned, namely signal coupling is achieved between the antenna and monitoring device without any physical electrical connection therebetween. The invention is depicted in FIGS. 6 and 7. In this embodiment, an anchoring patch 100 is used to connect the encapsulated monitoring device 102 to the innerliner 104 of a tire 106. In accordance with one of the objectives of the present invention, an antenna 108 is embedded within an anchoring layer 110 of anchoring patch 100. Communication is provided between antenna 108 and a monitoring device 112 when monitoring device 112 is attached to anchoring layer 110. The communication is provided through electrical coupling. Anchoring patch 100 includes a cover 114 formed from any of a variety of cured rubbers that is separated from anchoring layer 110 by a layer of cure material 116 such as cure paper or cure cloth. Anchoring layer 110 is fabricated from an uncured rubber that may be a dual cure rubber or a rubber cured either by heat or by a chemical reaction. Examples of anchoring patch 100 and methods for using the patch are taught in United States Patent Applications Serial Nos. 09/206,273 and 09/205,931, filed December4, 1998. Antenna 108 is connected to an electrical pad 118 that helps provide the electrical coupling between antenna 108 and monitoring device 112. Electrical pad 118 may be an integral part of antenna 108, an extension of antenna 108, or a separate element that is connected to antenna 108. Electrical pad 118 may be positioned adjacent the outer surface of anchoring layer 110. Encapsulated monitoring device 102 includes monitoring device 112 surrounded by an encapsulation material 120. Encapsulated monitoring device 102 is mounted on an attachment patch 122 that is used to mount encapsulated monitoring device 102 on tire 106. Another electrical pad 124 is disposed in attachment patch 122 and is directly connected to monitoring device 112 by a suitable connector 126. In other embodiments of the invention, the connection between electrical pad 124 and monitoring device 112 is formed by electrical coupling as described above. As shown in the drawings, the position of antenna 108 may be located away from bead ring 128 and apex filler 130 while allowing monitoring device 112 to be disposed closer to bead ring 128. The length and configuration of antenna 108 is not limited by the overall size of encapsulated monitoring device 102 or attachment pad 122 and may be configured to provide reliable communication with the data-gathering device positioned outside tire 106. Monitoring device 112 may be mounted on tire 106 in tne following manner. First, anchoring patch 100 is adhered to innerliner 104 by a suitable adhesive or by curing anchoring patch 100 to innerliner 104. This cure may be a chemical cure or a heat cure performed during the curing of the green tire. After anchoring patch 100 has been cured, cover 114 and cure material 116 are removed to allow attachment patch 122 carrying encapsulated monitoring device 102 to be directly adhered to anchoring layer 110. Attachment patch 122 may be adhered to anchoring layer 110 by a suitable adhesive or by providing a layer of uncured rubber such as a cushion gum or dual cure rubber on the outer surface of attachment patch 122 which is then cured to anchoring layer 110. Encapsulated monitoring device 102 is first positioned such that electrical pads 118 and 124 are aligned. Encapsulated monitoring device 102 and attachment patch 122 are then attached to anchoring layer 110. Electrical pads 118 and 124 remain aligned but spaced such that they provide electrical coupling between antenna 108 and electronic monitoring device 112. In FIG. 8, the antenna 200 is embedded within the innerliner 202 of the tire 204. Antenna 200 is embedded within innerliner 202 during the manufacture of innerliner 202 and may be ideally configured to communicate with a data gathering device (not shown) that is positioned outside of tire 204. An electrical pad 206 is connected to antenna 200 and provides communication between antenna 200 and an electronic monitoring device 208. Electrical pad 206 may be an integral part of antenna 200 and simply may be a portion of antenna 200 that is disposed in the correct position to function as electrical pad 206. Electronic monitoring device 208 is encapsulated with an encapsulation material 210 to form encapsulated monitoring device 212. Encapsulated monitoring device 212 is mounted on attachment patch 214. Another electrical pad 216 is embedded within attachment patch 214 and directly connected to electronic monitoring device 208 by a suitable connector 218. The connection between electrical pad 216 and electronic monitoring device 208 may be the direct connection depicted in FIG. 8 or may be formed by electrical coupling as described above with respect to FIGS. 1-5. Encapsulated monitoring device 212 is attached to attachment patch 214 by suitable means such as an adhesive. Attachment patch 214 is connected to innerliner 202 by suitable means such as an adhesive. Communication between antenna 200 and electronic monitoring device 208 is provided by aligning electrical pads 206 and 216 and then connecting attachment patch 214 to innerliner 202. Electrical pads 206 and 216 are aligned but spaced to provide electrical coupling through the material of innerliner 202 and attachment patch 214. The electrical coupling provides communication between antenna 200 and electronic monitoring device 208. Accordingly, the improved monitoring device and patch combination is simplified, provides an effective, safe, inexpensive, and efficient device that achieves all the enumerated objectives of the invention, provides for eliminating difficulties encountered with prior devices, and solves problems and obtains new results in the art. In the foregoing description, certain terms have been used for brevity, clearness, and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirement of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described. Having now described the features, discoveries, and principles of the invention, the manner in which the monitoring device and patch combination is constructed and used, the characteristics of the construction, and the advantageous new and useful results obtained, the new and useful structures, devices, elements, arrangements, parts, combinations, and methods are set forth in the appended claims.

Claims: A monitoring device and patch combination used to monitor the conditions of a pneumatic tire (106) having an inner-liner (104), the combination comprising: a monitoring device (112) having at least one sensing element; an attachment patch (122) carrying said monitoring device; an anchoring layers (110) adapted to adhere to the innerliner of the tire; an antenna (108) carried by said anchoring layer; and said attachment patch attached to said anchoring layer with said monitoring device (112) and said antenna being aligned and spaced apart to provide a signal coupling between the monitoring device and the antenna. The combination of Claim 1, further comprising a first electrical pad (124) connected to said monitoring device and a second electrical pad (118) connected to said antenna; said pads being aligned and spaced apart to provide the signal coupling between the monitoring device and the antenna. The combination of Claim 2, wherein said first electrical pad (124) is carried by said attachment patch (122) and said second electrical pad (118) is carried by said anchoring layer (110).

Inventors: KOCH RUSSEL W, TREW ROBERT J, WILSON PAUL B, KOCH, RUSSEL W., TREW, ROBERT J., WILSON, PAUL B.
Applicants: BRIDGESTONE FIRESTONE NORTH AM, BRIDGESTONE/FIRESTONE NORTH AMERICAN TIRE LLC
Application year: 2000
Main classification: B60C23
IPC codes: H01Q1, B60C23