US20030146679A1 - Chassis arrangement for reducing flame emissions - Google Patents
Chassis arrangement for reducing flame emissions Download PDFInfo
- Publication number
- US20030146679A1 US20030146679A1 US10/067,718 US6771802A US2003146679A1 US 20030146679 A1 US20030146679 A1 US 20030146679A1 US 6771802 A US6771802 A US 6771802A US 2003146679 A1 US2003146679 A1 US 2003146679A1
- Authority
- US
- United States
- Prior art keywords
- pcb
- chassis
- heat sink
- card
- shields
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/14—Mounting supporting structure in casing or on frame or rack
- H05K7/1422—Printed circuit boards receptacles, e.g. stacked structures, electronic circuit modules or box like frames
- H05K7/1424—Card cages
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
- H04Q1/02—Constructional details
- H04Q1/035—Cooling of active equipments, e.g. air ducts
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2201/00—Constructional details of selecting arrangements
- H04Q2201/06—Cooling arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2201/00—Constructional details of selecting arrangements
- H04Q2201/10—Housing details
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2201/00—Constructional details of selecting arrangements
- H04Q2201/12—Printed circuits
Definitions
- the present invention relates to chassis for electronic enclosures, and more particularly to an apparatus for reducing flame emissions from such chassis.
- the NEBS standard includes criteria, described in Section 4.2, that provide minimum fire resistance recommendations for CO telecommunication equipment. These criteria are designed to minimize the fire propagation hazard, and to minimize the likelihood that an equipment assembly fire will spread beyond the structural elements of the equipment on fire. These criteria address measurable conditions that include ignition of material in adjacent equipment frames and assemblies, and visible flames extending beyond the horizontal or vertical confines of the equipment on fire. Compliance to the standard is tested by introducing a flame source into the equipment under test, and observing how the equipment reacts once ignition has occurred.
- the present invention is a chassis arrangement that minimizes the lateral flame spread from card to card within the chassis, and increases heat dissipation from the chassis.
- the invention comprises a heat sink attached to the underside of the chassis cover to dissipate excess heat from within the chassis, and PCB shields disposed between the circuit cards of the chassis and acting in concert with the heat sink to act as physical and thermal barriers to prevent lateral flame spread from card to card due to flame and hot gas wrap-around.
- FIGURE shows an exploded view of a preferred embodiment of the present invention.
- Chassis 1 and chassis cover 2 comprise an equipment enclosure that defines enclosed internal compartment 7 for holding printed circuit board (PCB) assemblies such as PCB 3 .
- PCB printed circuit board
- a PCB shield 4 is disposed between all circuit boards 3 .
- Heat sink 5 is thermally coupled to the bottom face of chassis cover 2 .
- PCB shields 4 are of approximately the same height and depth as PCB cards 3 , and are oriented approximately coplanar with PCB cards 3 . More particularly, chassis 1 and PCB shields 4 are dimensioned such that the front and rear edges of PCB shields 4 , when PCB shields 4 are installed in chassis 1 , are approximately flush with the front and rear faces of internal compartment 7 in which PCB cards 3 are installed. In the context of the present invention, approximately flush can also mean actually flush. In addition, PCB shields 4 and heat sink 5 are dimensioned such that, when chassis cover 2 is installed on chassis 1 , the top edges of PCB shields 4 are approximately flush with the bottom face of heat sink 5 .
- PCB shields 4 Having an approximately flush relationship between the front, rear and top edges of PCB shields 4 and the front and rear faces of internal compartment 7 and the bottom face of heat sink 5 , respectively, operates to reduce or eliminate lateral flame spread from card to card due to flame and hot gas wrap-around at the edges of PCB cards 3 .
- PCB shields 4 act as a physical and thermal barrier between adjacent PCB cards 3 such that a PCB card that is on fire or emitting hot gasses does not expose the opposing face of an adjacent PCB card to flame, excessive heat or hot gasses, and directs excessive heat towards heat sink 5 .
- the dimensioning of PCB shields 4 and the proximal relationship of the edges of PCB shields 4 to the faces of internal compartment 7 and the bottom face of heat sink 5 is such that lateral flame spread from card to card due to flame and hot gas wrap-around at the edges of PCB cards 3 is greatly reduced or eliminated.
- PCB shields 4 may only need to extend a small amount beyond the front and/or rear edges of PCB cards 3 to reduce lateral flame spread.
- PCB shields 4 may allow PCB shields 4 to be dimensioned smaller than PCB cards 3 and positioned between PCB cards 3 so as to be effective in reducing or eliminating flame spread from card to card.
- Other considerations in the positioning, orientation and thickness of PCB shields 4 include that the shields not adversely affect the internal normal operating temperature of the equipment assembly because of excessive air blockage or air flow impedance.
- PCB shields 4 comprise 0.019′′ galvanized sheet steel with a backing of flame retardant non-conductive fiberglass cloth tape.
- the tape also acts to prevent shorts on the card during installation and removal. This combination of materials proves to perform satisfactorily, is easy to fabricate, and is relatively inexpensive. Other materials may be used that satisfy specific design, performance and economic criteria.
- Heat sink 5 operates to dissipate heat from within internal compartment 7 so as to reduce the intensity of flames that may be present on PCB cards 3 , and to reduce the incidence of flame ignition on PCB cards 3 due to excessive heat build-up in internal compartment 7 .
- Heat sink 5 is dimensioned laterally such that it at least spans PCB cards 3 such that excess heat generated by ignition of combustible material on a card can rise and be transferred to heat sink 5 .
- heat sink 5 extends approximately the entire width of chassis cover 2 .
- heat sink 5 need only span sufficiently to dissipate excess heat generated from ignition and flames from PCB cards 3 , and also satisfy the desire to reduce card to card flame spread from flame wrap-around over the top edge of PCB cards 3 .
- heat sink 5 may not need to span the entire width of internal compartment 7 .
- heat sink 5 need only be sufficient to dissipate excess heat generated from ignition and flames from PCB cards 3 , and also satisfy the desire to reduce card to card flame spread from flame wrap-around over the top edge of PCB cards 3 .
- heat sink 5 extends from the front of internal compartment 7 to the vent holes at the rear portion of chassis cover 2 .
- the selection of material for heat sink 5 is based on criteria that include mass, flammability, thermal conductivity, linear thermal expansion, cost, availability and ease of fabrication. In the preferred embodiment, 0.3125′′ plate aluminum is used. However, any suitable material that satisfies the design and selection criteria may be used.
- Heat sink 5 is sufficiently thermally coupled to the bottom face of chassis cover 2 so as to allow the transmission of heat from heat sink 5 through chassis cover 2 and to the environment.
- the coupling means for attaching heat sink 5 to chassis cover 2 is not, per se, important, and may comprise, for example, screws, rivets, retaining tabs, or thermal coupling adhesive.
- An alternative embodiment for heat sink 5 and chassis cover 2 comprises a heat sink 5 having a longitudinal dimension that is shorter than that of PCB cards 3 , and includes non-flammable material, such as foam or tape, attached to chassis cover 2 adjacent to heat sink 5 , and above and approximately or actually flush with PCB cards 3 .
- heat sink satisfies the thermal related criteria, and heat sink 5 and the non-flammable material act in concert to reduce or eliminate lateral flame spread from card to card due to flame and hot gas wrap-around at the top edges of PCB cards 3 .
- a second alternative embodiment includes a thermal fuse attached to any cooling fans in the equipment assembly that may vent hot gasses and flames outside the equipment enclosure. In the event of a fire that produces excessive heat within the enclosure, the cooling fans shut down.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Networks & Wireless Communication (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
- Casings For Electric Apparatus (AREA)
Abstract
A chassis arrangement that minimizes lateral flame spread from card to card within the chassis, and increases heat dissipation from the chassis, comprising a heat sink attached to the inside of the chassis cover to dissipate excess heat from within the chassis, and PCB shields disposed between the circuit cards of the chassis and acting in concert with the heat sink to act as physical and thermal barriers to prevent lateral flame spread from card to card due to flame and hot gas wrap-around.
Description
- The present invention relates to chassis for electronic enclosures, and more particularly to an apparatus for reducing flame emissions from such chassis.
- For telecommunications equipment installed in central offices (COs) and other telephone buildings, it is recommended that the equipment meet certain minimum equipment-building interface, physical dimension and environmental performance criteria. One such set of criteria is Telcordia standards document GR-63-CORE, “Network Equipment-Building System (NEBS) Requirements: Physical Protection,” Issue 1, October, 1995.
- With certain equipment failures, it is possible for some components to overheat to the extent that they ignite a fire. The NEBS standard includes criteria, described in Section 4.2, that provide minimum fire resistance recommendations for CO telecommunication equipment. These criteria are designed to minimize the fire propagation hazard, and to minimize the likelihood that an equipment assembly fire will spread beyond the structural elements of the equipment on fire. These criteria address measurable conditions that include ignition of material in adjacent equipment frames and assemblies, and visible flames extending beyond the horizontal or vertical confines of the equipment on fire. Compliance to the standard is tested by introducing a flame source into the equipment under test, and observing how the equipment reacts once ignition has occurred.
- The present invention is a chassis arrangement that minimizes the lateral flame spread from card to card within the chassis, and increases heat dissipation from the chassis. The invention comprises a heat sink attached to the underside of the chassis cover to dissipate excess heat from within the chassis, and PCB shields disposed between the circuit cards of the chassis and acting in concert with the heat sink to act as physical and thermal barriers to prevent lateral flame spread from card to card due to flame and hot gas wrap-around.
- The FIGURE shows an exploded view of a preferred embodiment of the present invention.
- The FIGURE shows an exploded view of a preferred embodiment of the present invention. Chassis1 and
chassis cover 2 comprise an equipment enclosure that defines enclosedinternal compartment 7 for holding printed circuit board (PCB) assemblies such as PCB 3. A PCB shield 4 is disposed between allcircuit boards 3. Heat sink 5 is thermally coupled to the bottom face ofchassis cover 2. - In the preferred embodiment, PCB shields4 are of approximately the same height and depth as
PCB cards 3, and are oriented approximately coplanar withPCB cards 3. More particularly, chassis 1 and PCB shields 4 are dimensioned such that the front and rear edges of PCB shields 4, when PCB shields 4 are installed in chassis 1, are approximately flush with the front and rear faces ofinternal compartment 7 in whichPCB cards 3 are installed. In the context of the present invention, approximately flush can also mean actually flush. In addition, PCB shields 4 and heat sink 5 are dimensioned such that, whenchassis cover 2 is installed on chassis 1, the top edges of PCB shields 4 are approximately flush with the bottom face of heat sink 5. Having an approximately flush relationship between the front, rear and top edges of PCB shields 4 and the front and rear faces ofinternal compartment 7 and the bottom face of heat sink 5, respectively, operates to reduce or eliminate lateral flame spread from card to card due to flame and hot gas wrap-around at the edges ofPCB cards 3. In addition, PCB shields 4 act as a physical and thermal barrier betweenadjacent PCB cards 3 such that a PCB card that is on fire or emitting hot gasses does not expose the opposing face of an adjacent PCB card to flame, excessive heat or hot gasses, and directs excessive heat towards heat sink 5. Since heat, hot gasses and flames tend to naturally rise, a flush relationship between the bottom edge of PCB shields 4 and the bottom face ofinternal compartment 7 is not critical for the reduction of lateral flame spread from card to card due to flame and hot gas wrap-around at the edges ofPCB cards 3. - In general, the dimensioning of PCB shields4 and the proximal relationship of the edges of PCB shields 4 to the faces of
internal compartment 7 and the bottom face of heat sink 5 is such that lateral flame spread from card to card due to flame and hot gas wrap-around at the edges ofPCB cards 3 is greatly reduced or eliminated. For example, ifinternal compartment 7 is deeper thanPCB cards 3, PCB shields 4 may only need to extend a small amount beyond the front and/or rear edges ofPCB cards 3 to reduce lateral flame spread. Also, while design of PCB shields 4 to cover as much ofPCB cards 3 as possible will tend to minimize lateral flame spread, the positioning of combustible material and concentration of fuel load onPCB cards 3 may allow PCB shields 4 to be dimensioned smaller thanPCB cards 3 and positioned betweenPCB cards 3 so as to be effective in reducing or eliminating flame spread from card to card. Other considerations in the positioning, orientation and thickness of PCB shields 4 include that the shields not adversely affect the internal normal operating temperature of the equipment assembly because of excessive air blockage or air flow impedance. - In the preferred embodiment, PCB shields4 comprise 0.019″ galvanized sheet steel with a backing of flame retardant non-conductive fiberglass cloth tape. The tape also acts to prevent shorts on the card during installation and removal. This combination of materials proves to perform satisfactorily, is easy to fabricate, and is relatively inexpensive. Other materials may be used that satisfy specific design, performance and economic criteria.
- In the preferred embodiment, PCB shields4 are attached to
PCB cards 3 by screws and standoffs at the rear of the card at card handle 6, and at the front of the card. The flame retardant tape is applied to the face of PCB shield 4 that faces the PCB card to which the shield is attached. The specific means to dispose PCB shields 4 betweenPCB cards 3 is not important as long as the objectives of the present invention are met. - Heat sink5 operates to dissipate heat from within
internal compartment 7 so as to reduce the intensity of flames that may be present onPCB cards 3, and to reduce the incidence of flame ignition onPCB cards 3 due to excessive heat build-up ininternal compartment 7. - Heat sink5 is dimensioned laterally such that it at least spans
PCB cards 3 such that excess heat generated by ignition of combustible material on a card can rise and be transferred to heat sink 5. In the preferred embodiment, heat sink 5 extends approximately the entire width ofchassis cover 2. Generally, whereinternal compartment 7 may be wider than the portion reserved for card installation, heat sink 5 need only span sufficiently to dissipate excess heat generated from ignition and flames fromPCB cards 3, and also satisfy the desire to reduce card to card flame spread from flame wrap-around over the top edge ofPCB cards 3. Thus, heat sink 5 may not need to span the entire width ofinternal compartment 7. Similarly, generally, the longitudinal dimension of heat sink 5 need only be sufficient to dissipate excess heat generated from ignition and flames fromPCB cards 3, and also satisfy the desire to reduce card to card flame spread from flame wrap-around over the top edge ofPCB cards 3. In the preferred embodiment, heat sink 5 extends from the front ofinternal compartment 7 to the vent holes at the rear portion ofchassis cover 2. - The selection of material for heat sink5 is based on criteria that include mass, flammability, thermal conductivity, linear thermal expansion, cost, availability and ease of fabrication. In the preferred embodiment, 0.3125″ plate aluminum is used. However, any suitable material that satisfies the design and selection criteria may be used.
- Heat sink5 is sufficiently thermally coupled to the bottom face of
chassis cover 2 so as to allow the transmission of heat from heat sink 5 throughchassis cover 2 and to the environment. The coupling means for attaching heat sink 5 tochassis cover 2 is not, per se, important, and may comprise, for example, screws, rivets, retaining tabs, or thermal coupling adhesive. - An alternative embodiment for heat sink5 and
chassis cover 2 comprises a heat sink 5 having a longitudinal dimension that is shorter than that ofPCB cards 3, and includes non-flammable material, such as foam or tape, attached tochassis cover 2 adjacent to heat sink 5, and above and approximately or actually flush withPCB cards 3. In this arrangement, heat sink satisfies the thermal related criteria, and heat sink 5 and the non-flammable material act in concert to reduce or eliminate lateral flame spread from card to card due to flame and hot gas wrap-around at the top edges ofPCB cards 3. - A second alternative embodiment includes a thermal fuse attached to any cooling fans in the equipment assembly that may vent hot gasses and flames outside the equipment enclosure. In the event of a fire that produces excessive heat within the enclosure, the cooling fans shut down.
- While the present invention has been shown and described with respect to exemplary embodiments, it will be understood by those skilled in the art that modifications may be made thereto without departing from the scope and spirit of the invention. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.
Claims (5)
1. A chassis arrangement for reducing flame emissions, a chassis and chassis cover defining an internal compartment having printed circuit board (PCB) cards installed within, said chassis arrangement comprising:
a heat sink thermally coupled to the bottom face of the chassis cover so as to allow the transmission of excess heat from the internal compartment through said heat sink and the chassis cover and to the environment; and
PCB shields disposed between the PCB cards, said PCB shields acting as physical and thermal barriers between adjacent PCB cards, said PCB shields acting in concert with said heat sink to prevent or reduce lateral flame spread from PCB card to PCB card due to flame wrap-around and to direct excess heat toward said heat sink.
2. A chassis arrangement according to claim 1 , wherein the top edges of said PCB shields are approximately flush with the bottom face of said heat shield.
3. A chassis arrangement according to claim 1 , wherein the top edges of said PCB shields are approximately flush with the bottom face of said heat shield, and the front and rear edges of said PCB shields are approximately flush with the front and rear faces, respectively, of the internal compartment.
4. A chassis arrangement according to claim 2 , further comprising non-flammable material attached to the chassis cover, adjacent to said heat sink, and approximately flush with the top edges of the PCB cards, said non-flammable material acting in concert with said heat sink to prevent or reduce lateral flame spread from PCB card to PCB card due to flame wrap-around.
5. A chassis arrangement according to claim 1 , the chassis further comprising a forced air cooling system, said chassis arrangement further comprising a thermal fuse acting to shut down the forced air cooling system, thereby reducing the venting of hot gasses or flames outside the chassis.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/067,718 US20030146679A1 (en) | 2002-02-07 | 2002-02-07 | Chassis arrangement for reducing flame emissions |
CA002407931A CA2407931A1 (en) | 2002-02-07 | 2002-10-11 | Chassis arrangement for reducing flame emissions |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/067,718 US20030146679A1 (en) | 2002-02-07 | 2002-02-07 | Chassis arrangement for reducing flame emissions |
Publications (1)
Publication Number | Publication Date |
---|---|
US20030146679A1 true US20030146679A1 (en) | 2003-08-07 |
Family
ID=27658904
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/067,718 Abandoned US20030146679A1 (en) | 2002-02-07 | 2002-02-07 | Chassis arrangement for reducing flame emissions |
Country Status (2)
Country | Link |
---|---|
US (1) | US20030146679A1 (en) |
CA (1) | CA2407931A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070230123A1 (en) * | 2006-03-31 | 2007-10-04 | Koji Hata | Electronic apparatus |
CN108382684A (en) * | 2018-05-05 | 2018-08-10 | 广州智汇信息技术有限公司 | One kind being based on block chain believable intelligent contract hardened system |
Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5811050A (en) * | 1994-06-06 | 1998-09-22 | Gabower; John F. | Electromagnetic interference shield for electronic devices |
US6011701A (en) * | 1997-03-08 | 2000-01-04 | Dmt Gmbh, Feinwerktechnische Komplettlosungen | Component housing for integration with furniture |
US6285548B1 (en) * | 2000-08-18 | 2001-09-04 | Quantum Bridge Communications, Inc. | Face plate for a chassis for high frequency components |
US6288759B1 (en) * | 1997-10-02 | 2001-09-11 | Samsung Electronics Co., Ltd. | Display device having fire-retardant shield case |
US6301108B1 (en) * | 1999-12-27 | 2001-10-09 | Westell, Inc. | Chassis containing electronic components with fire containment trap door |
US6322377B2 (en) * | 1998-09-15 | 2001-11-27 | Tvm Group. Inc. | Connector and male electrical contact for use therewith |
US6354680B1 (en) * | 1999-08-26 | 2002-03-12 | Hon Hai Precision Ind. Co., Ltd. | Computer enclosure |
US6384331B1 (en) * | 2001-01-08 | 2002-05-07 | Micro-Star Int'l Co., Ltd. | Secured reinforcing support device for a heat sink |
US20020053861A1 (en) * | 1998-10-21 | 2002-05-09 | Steinberg Kari Frances | Computer monitor cover |
US20020093788A1 (en) * | 1997-10-25 | 2002-07-18 | Philon Rothschild | Housing for data storage devices or for accommodating such devices |
US20020108743A1 (en) * | 2000-12-11 | 2002-08-15 | Wirtz Richard A. | Porous media heat sink apparatus |
US20030062180A1 (en) * | 2001-10-02 | 2003-04-03 | Peter Jones | EMI shielding gasket construction |
US6626507B2 (en) * | 2001-07-09 | 2003-09-30 | Hewlett-Packard Development Company, L.P. | Fire shield for air ventilation holes of a computer chassis |
-
2002
- 2002-02-07 US US10/067,718 patent/US20030146679A1/en not_active Abandoned
- 2002-10-11 CA CA002407931A patent/CA2407931A1/en not_active Abandoned
Patent Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5811050A (en) * | 1994-06-06 | 1998-09-22 | Gabower; John F. | Electromagnetic interference shield for electronic devices |
US6011701A (en) * | 1997-03-08 | 2000-01-04 | Dmt Gmbh, Feinwerktechnische Komplettlosungen | Component housing for integration with furniture |
US6288759B1 (en) * | 1997-10-02 | 2001-09-11 | Samsung Electronics Co., Ltd. | Display device having fire-retardant shield case |
US20020093788A1 (en) * | 1997-10-25 | 2002-07-18 | Philon Rothschild | Housing for data storage devices or for accommodating such devices |
US6322377B2 (en) * | 1998-09-15 | 2001-11-27 | Tvm Group. Inc. | Connector and male electrical contact for use therewith |
US20020053861A1 (en) * | 1998-10-21 | 2002-05-09 | Steinberg Kari Frances | Computer monitor cover |
US6354680B1 (en) * | 1999-08-26 | 2002-03-12 | Hon Hai Precision Ind. Co., Ltd. | Computer enclosure |
US6301108B1 (en) * | 1999-12-27 | 2001-10-09 | Westell, Inc. | Chassis containing electronic components with fire containment trap door |
US6285548B1 (en) * | 2000-08-18 | 2001-09-04 | Quantum Bridge Communications, Inc. | Face plate for a chassis for high frequency components |
US20020108743A1 (en) * | 2000-12-11 | 2002-08-15 | Wirtz Richard A. | Porous media heat sink apparatus |
US6384331B1 (en) * | 2001-01-08 | 2002-05-07 | Micro-Star Int'l Co., Ltd. | Secured reinforcing support device for a heat sink |
US6626507B2 (en) * | 2001-07-09 | 2003-09-30 | Hewlett-Packard Development Company, L.P. | Fire shield for air ventilation holes of a computer chassis |
US20030062180A1 (en) * | 2001-10-02 | 2003-04-03 | Peter Jones | EMI shielding gasket construction |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070230123A1 (en) * | 2006-03-31 | 2007-10-04 | Koji Hata | Electronic apparatus |
US7551436B2 (en) * | 2006-03-31 | 2009-06-23 | Hitachi Communication Technologies, Ltd. | Electronic apparatus |
CN108382684A (en) * | 2018-05-05 | 2018-08-10 | 广州智汇信息技术有限公司 | One kind being based on block chain believable intelligent contract hardened system |
Also Published As
Publication number | Publication date |
---|---|
CA2407931A1 (en) | 2003-08-07 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: AG COMMUNICATION SYSTEMS CORP., ARIZONA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GLIESMAN, PAUL A.;RE, THOMAS W.;GILES, THOMAS C.;AND OTHERS;REEL/FRAME:012608/0834;SIGNING DATES FROM 20011127 TO 20011208 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |