CN215644032U - Pull plate insulation structure for dry type transformer - Google Patents
Pull plate insulation structure for dry type transformer Download PDFInfo
- Publication number
- CN215644032U CN215644032U CN202122084748.2U CN202122084748U CN215644032U CN 215644032 U CN215644032 U CN 215644032U CN 202122084748 U CN202122084748 U CN 202122084748U CN 215644032 U CN215644032 U CN 215644032U
- Authority
- CN
- China
- Prior art keywords
- insulation
- pulling plate
- pulling
- dry
- plate
- 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.)
- Active
Links
- 238000009413 insulation Methods 0.000 title claims abstract description 82
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 18
- 230000017525 heat dissipation Effects 0.000 claims abstract description 10
- 230000000452 restraining effect Effects 0.000 claims abstract description 3
- 239000012212 insulator Substances 0.000 claims description 33
- 239000004744 fabric Substances 0.000 claims description 10
- 239000004593 Epoxy Substances 0.000 claims description 9
- 239000011521 glass Substances 0.000 claims description 9
- 125000006850 spacer group Chemical group 0.000 claims description 3
- 229920001296 polysiloxane Polymers 0.000 claims 1
- 230000002035 prolonged effect Effects 0.000 abstract 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000000741 silica gel Substances 0.000 description 4
- 229910002027 silica gel Inorganic materials 0.000 description 4
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 239000003063 flame retardant Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000009428 plumbing Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Landscapes
- Transformers For Measuring Instruments (AREA)
Abstract
The utility model relates to a pulling plate insulation structure for a dry-type transformer, which belongs to the technical field of transformers and comprises an iron core column and pulling plates arranged on two sides of the iron core column, wherein pulling plate insulation is arranged between the pulling plates and the iron core column, the edge of the pulling plate insulation completely exceeds the edge of the pulling plates, clamping piece insulation is arranged on one side of the pulling plates, which is far away from the pulling plate insulation, a plurality of cushion blocks which are tightly attached to the iron core column are uniformly distributed on one side of the clamping piece insulation, which is close to the iron core column, and a heat dissipation groove for restraining the pulling plates and the pulling plate insulation is formed between the adjacent cushion blocks. According to the pull plate insulation structure for the dry-type transformer, the length edge of the pull plate insulation is firstly prolonged, the clamp insulation is adjusted to the side, far away from the pull plate insulation, of the pull plate, so that a gap is prevented from being generated between the pull plate insulation and the clamp insulation during assembly, the problem of reduction of insulation resistance caused by the existence of the gap is solved, the heat dissipation grooves among the cushion blocks can facilitate air flow to take away heat through the surfaces of the iron core columns, and the practicability is good.
Description
Technical Field
The utility model relates to a pulling plate insulation structure for a dry-type transformer, and belongs to the technical field of transformers.
Background
The transformer is a static electric equipment for transforming AC voltage and current to transmit AC energy, and realizes the transmission of electric energy based on the principle of electromagnetic induction. Transformers can be classified into power transformers, test transformers, instrument transformers, and transformers for special purposes, in terms of their use: the power transformer is necessary equipment for power transmission and distribution and power consumer distribution; the device is used for carrying out voltage withstand (boosting) test on electrical equipment by the test transformer; the instrument transformer is used for electrical measurement and relay protection of a power distribution system; the transformer for special purposes comprises a furnace transformer for smelting, an electric welding transformer, a rectifier transformer for electrolysis, a small-sized regulating transformer and the like. Power transformers are classified by insulating medium: oil-immersed transformers (flame-retardant type and non-flame-retardant type), dry-type transformers and gas-insulated transformers.
The dry-type transformer has the advantages of strong short-circuit resistance, small maintenance workload, high operation efficiency, small volume, low noise and the like, so the dry-type transformer is commonly used in places with high performance requirements on fire prevention, explosion prevention and the like, such as local illumination, high-rise buildings, airports, wharf CNC mechanical equipment and the like. The insulation performance of the dry power transformer plays a decisive role in the safe operation of the product, so the requirements of the insulation structure and the insulation material of the dry power transformer are stricter than those of an oil immersed type, and the requirements on the flame retardant performance of the insulation structure are higher.
The pulling plate in the existing dry-type transformer is usually made of stainless steel, and a pulling plate insulator and a clamping piece insulator are generally arranged between the pulling plate and the core limb to respectively insulate the pulling plate and the clamping piece. As shown in fig. 9, in the prior art, a pulling plate insulator 40 and a clamping piece insulator 50 are located between a core limb 10 and a pulling plate 30, a gap 1 exists between the pulling plate insulator 40 and the clamping piece insulator 50 during assembly, for example, if there are six pulling plates 30 inside a transformer, there are six pulling plate insulators 40 correspondingly, there is a gap 1 at both upper and lower ends of each pulling plate insulator 40, there are twelve gaps 1 inside the transformer, and after the transformer is installed and used in a basement or a ground distribution room, after normal power transmission for one week or more, the transformer is affected by underground moisture and humidity temperature, especially in a coastal and thunder and lightning prone area, alkaline moisture enters the inside of the transformer and adheres to the gap 1, and insulation resistance is obviously reduced due to the influence of alkalinity and humidity, and even multi-point grounding is caused, and normal operation of the transformer is affected. Therefore, how to improve the existing pulling plate insulation structure has important significance for improving the reliability of the pulling plate insulation structure.
Disclosure of Invention
Therefore, the utility model provides a pulling plate insulation structure for a dry type transformer, which comprises the steps of firstly extending the length edge of the pulling plate insulation to be completely beyond the edge of the pulling plate, and then adjusting the position of the clamping piece insulation to one side of the pulling plate far away from the pulling plate insulation, namely the inner sides of the pulling plate, an upper clamping piece and a lower clamping piece, so that the problem that the clamping piece insulation and the pulling plate insulation are arranged on the same side of the pulling plate to generate gaps is avoided. In order to achieve the above purpose, the utility model provides the following technical scheme:
the utility model provides a arm-tie insulation system for dry-type transformer, includes the core leg and sets up the arm-tie in the core leg both sides, it is insulating to be provided with the arm-tie between arm-tie and the core leg, the edge that the arm-tie is insulating surpasss the edge of arm-tie completely, it is insulating to keep away from one side of arm-tie on the arm-tie and is provided with the folder, one side evenly distributed that is close to the core leg on the folder is insulating has a plurality of cushions of hugging closely the core leg, forms between the adjacent cushion and is used for retraining the radiating groove that arm-tie and arm-tie are insulating.
As an improvement of the scheme, the pulling plate is provided with a pulling plate mounting hole, and the clamping piece is provided with an embedding hole corresponding to the pulling plate mounting hole in an insulating way.
As an improvement of the scheme, the pull plate extends outwards to form a positioning nail at a position close to the pull plate mounting hole, and the insulating nesting hole of the clamping piece is sleeved on the positioning nail.
As an improvement of the scheme, the iron core column is of a structure in a shape of a Chinese character ri, three groups of pulling plates are respectively arranged on two sides of the iron core column, and the clamping pieces are arranged on the pulling plates on the same side of the iron core column in an insulating mode.
As an improvement of the scheme, the pulling plate is provided with a strip-shaped hole.
As an improvement of the scheme, the pulling plate insulation and the clamping piece insulation are made of epoxy glass cloth plates.
As an improvement of the scheme, the cushion block is made of an epoxy glass cloth plate or a silica gel plate.
As an improvement of the scheme, a transformer coil is sleeved outside the iron core column.
The pulling plate insulation structure for the dry-type transformer provided by the utility model has the following two advantages:
(1) the length edge of the pulling plate insulation is extended, so that the edge of the pulling plate insulation completely exceeds the edge of the pulling plate, and the clamp insulation is adjusted to one side of the pulling plate far away from the pulling plate insulation, namely the inner sides of the pulling plate, the upper clamp and the lower clamp;
(2) the clamp is insulating can play the guard action of certain degree to the iron core post, and the insulating cushion of last on the clamp can form the radiating groove on the one hand, and on the other hand can support the iron core post, when the clamp tightens up, guarantees that the atress is even between clamp insulation and the iron core post, simultaneously because the transformer during operation iron core post can produce the heat, and the radiating groove that forms between the adjacent cushion can make things convenient for the air current to pass through the iron core post surface and will take away the heat to guarantee the smooth heat dissipation of iron core post terminal surface.
Drawings
Fig. 1 is a schematic structural view of a pull plate insulation structure for a dry-type transformer according to the present invention;
FIG. 2 is an enlarged view of a portion of area A of FIG. 1;
fig. 3 is a schematic view of a tab insulation structure for a dry type transformer according to the present invention, viewed from one side;
fig. 4 is a schematic structural view of a pulling plate used in a pulling plate insulation structure of a dry-type transformer according to the present invention;
fig. 5 is a schematic view of a tab in a tab insulation structure for a dry type transformer according to the present invention, viewed from one side;
fig. 6 is a schematic structural view of a tab insulation in a tab insulation structure for a dry-type transformer according to the present invention;
FIG. 7 is a schematic diagram of the structure of the clip insulation in the pull plate insulation structure of the dry-type transformer according to the present invention;
fig. 8 is a schematic view of the clip insulation in the tab insulation structure for a dry-type transformer according to the present invention, as viewed from one side;
FIG. 9 is a schematic view of a prior art assembled pulling plate insulator and clamping piece insulator;
fig. 10 is a schematic view illustrating the assembly of the tab insulation and the clip insulation in the tab insulation structure for the dry type transformer according to the present invention.
In the figure: 1-gap, 10-core column, 20-transformer coil, 30-pulling plate, 31-pulling plate mounting hole, 32-strip-shaped hole, 33-positioning nail, 40-pulling plate insulation, 50-clamping piece insulation, 51-cushion block, 52-nesting hole and 53-radiating groove.
Detailed Description
The present invention is described in terms of particular embodiments, other advantages and features of the utility model will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the utility model and that it is not intended to limit the utility model to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the present specification, the terms "inside" and "outside" are used for the sake of clarity only, and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship between the terms and the terms are also considered to be within the scope of the present invention without substantial changes in the technical content.
In the description of the embodiments that follow, unless explicitly stated or limited otherwise, the terms "disposed," "connected," and the like are to be construed broadly and include, for example, "connected" that may be either fixedly connected or detachably connected, or integrally formed; may be a mechanical, plumbing, or electrical connection, may be indirectly connected through intervening media, may be internal to two elements, or may be in an interactive relationship with two elements, unless expressly defined otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
As shown in fig. 1, 2, 3, 6, 7, 8, and 10, the present invention provides a pulling plate insulation structure for a dry-type transformer, including a core limb 10 and pulling plates 30 disposed at two sides of the core limb 10, wherein a pulling plate insulation 40 is disposed between the pulling plates 30 and the core limb 10, an edge of the pulling plate insulation 40 completely exceeds an edge of the pulling plate 30, a clamping piece insulation 50 is disposed at a side of the pulling plate 30 away from the pulling plate insulation 40, a plurality of spacers 51 tightly attached to the core limb 10 are uniformly distributed at a side of the clamping piece insulation 50 close to the core limb 10, and a heat dissipation groove 53 for restraining the pulling plates 30 and the pulling plate insulation 40 is formed between adjacent spacers 51.
The transformer coil 20 is sleeved outside the core limb 10, the pulling plate 30 is made of stainless steel, the pulling plate 30 and the core limb 10 are both arranged inside the transformer coil 20, the pulling plate 30 mainly plays a role in fixing the transformer coil 20, and the core limb 10 plays a role in forming a magnetic loop. In order to make the pulling plate 30 and the core limb 10 in an insulating state, the pulling plate insulator 40 needs to be arranged between the pulling plate 30 and the core limb 10, the pulling plate insulator 40 can be made of epoxy glass cloth plate with good insulation, and the edge of the pulling plate insulator 40 needs to completely exceed the edge of the pulling plate 30, so as to ensure that a reliable insulating structure is formed between the pulling plate 30 and the core limb 10. The edge of the tab insulator 40 is divided into a length edge in the length direction and a width edge in the width direction, and the length edge of the present application mainly extends the length edge.
The clip insulation 50 is located on the side of the pulling plate 30 away from the pulling plate insulation 40, i.e., the inner side of the pulling plate and the upper and lower clips, which are both located outside the clip insulation 50 (not shown). The structure that this kind of folder is insulating 50 and arm-tie is insulating 40 and sets up respectively in arm-tie 30 both sides of this application, can not have as shown in figure 9 folder is insulating 50 and arm-tie is insulating 40 and set up in arm-tie 30 homonymy and produce the problem of clearance 1, has avoided the problem that clearance 1 department insulating properties variation that the transformer exists when working in alkaline or humidity environment, has improved the insulating properties of arm-tie 30.
One side that deviates from the arm-tie insulation 40 on the arm-tie 30 sets up folder insulation 50, the one side evenly distributed that is close to the core leg 10 on the folder insulation 50 has a plurality of cushion blocks 51 of hugging closely core leg 10, form radiating groove 53 between the adjacent cushion block 51, hold and restraint arm-tie insulation 40 through radiating groove 53, the width of arm-tie insulation 40 is best no longer than radiating groove 53's width, like this when the insulating 50 cushion block 51 of folder hugs closely core leg 10, arm-tie insulation 40 just can restrict in radiating groove 53. The pulling plate 30 and the clamping piece insulator 50 are fixed together, so that the clamping piece insulator 50 is ensured to be in a fixed state, and the movement of the pulling plate 30 and the pulling plate insulator 40 is restrained and limited.
As shown in fig. 4 and 7, the pulling plate 30 is provided with a pulling plate mounting hole 31, and the clip insulator 50 is provided with a nesting hole 52 corresponding to the pulling plate mounting hole 31. The clip insulator 50 and the pulling plate 30 can be fastened together by fasteners, such as fastening bolts, passing through the pulling plate mounting holes 31 and the nesting holes 52. The pulling plate 30 and the pulling plate insulator 40 both penetrate through the heat dissipation groove 53, and both sides of the pulling plate 30 and the pulling plate insulator 40 are constrained by the heat dissipation groove 53, and after the clamping piece insulator 50 and the pulling plate 30 are tightly connected through the fastener, the pulling plate 30 is also positioned inside the heat dissipation groove 53, so that the pulling plate 30 is protected to a certain extent.
The heat dissipation grooves 53 can restrain and protect the tab 30 and the tab insulator 40, and can also form a ventilation structure on the surface of the core limb 10, thereby accelerating the heat dissipation of the core limb 10. The strip-shaped holes 32 are used for magnetic isolation, so that a magnetic circuit is prevented from being formed on the pulling plate 30, and additional loss is reduced.
As shown in fig. 5, in order to improve the fixing effect between the clip insulator 50 and the pulling plate 30, a positioning pin 33 is formed on the pulling plate 30 at a position close to the pulling plate mounting hole 31 and extends outwards, a nesting hole 52 of the clip insulator 50 can be nested on the positioning pin 33, and after the nesting hole 52 of the clip insulator 50 is nested on the positioning pin 33 of the pulling plate 30, the clip insulator is connected with the positioning pin 33 through a fastener, such as a nut.
The clip insulator 50 may be made of an epoxy glass cloth plate having the same material as the pull plate insulator 40, the pad 51 may be made of an epoxy glass cloth plate or a silica gel plate, and the silica gel plate may be used to flexibly support the surface of the core limb 10, but the service life of the silica gel plate is shorter than that of the epoxy glass cloth plate. The epoxy glass cloth plate is a laminated product formed by hot pressing glass fiber cloth which is chemically treated as a base material and epoxy resin as an adhesive, and has the advantages of high mechanical strength at high temperature and good electrical performance stability at high humidity.
In the above scheme, the core limb 10 is in a "r" shape, three groups of pulling plates 30 are respectively disposed on two sides of the core limb 10, and the clamping piece insulation 50 is disposed on the pulling plates 30 on the same side of the core limb 10. In the scheme, three embedding holes 52 need to be formed in the clamp insulation 50, and the three embedding holes 52 are respectively connected with the pulling plate mounting holes 31 on the pulling plate 30.
Although the present invention has been described in detail hereinabove with reference to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made to the embodiments of the present invention. Accordingly, such modifications and improvements are intended to be within the scope of the utility model as claimed.
Claims (8)
1. The utility model provides a arm-tie insulation system for dry-type transformer, includes the core leg and sets up the arm-tie in core leg both sides, it is insulating to be provided with the arm-tie between arm-tie and the core leg, the edge that the arm-tie is insulating surpasss the edge of arm-tie completely, its characterized in that: the pull plate is characterized in that a clamping piece insulator is arranged on one side, far away from the pull plate insulator, of the pull plate, a plurality of cushion blocks tightly attached to the iron core column are uniformly distributed on one side, close to the iron core column, of the clamping piece insulator, and heat dissipation grooves used for restraining the pull plate and the pull plate insulator are formed between the adjacent cushion blocks.
2. The pulling plate insulating structure for dry-type transformers according to claim 1, wherein the pulling plate is formed with a pulling plate mounting hole, and the clamping member insulating structure is formed with a nesting hole corresponding to the pulling plate mounting hole.
3. A tab insulation structure for a dry-type transformer as claimed in claim 2, wherein said tab is formed with a positioning pin extending outward from a position adjacent to said tab mounting hole, and said nesting hole of said clip insulation is fitted on said positioning pin.
4. The pulling plate insulation structure for dry type transformer as claimed in claim 1, wherein said core leg is a "r" shaped structure, three sets of pulling plates are respectively disposed on two sides of said core leg, and said clamping member insulation is disposed on the pulling plates on the same side of the core leg.
5. The pulling plate insulating structure for dry-type transformers according to claim 1, wherein the pulling plate is provided with a strip-shaped hole.
6. The tab insulation structure for a dry-type transformer according to claim 1, wherein said tab insulation and clip insulation are made of epoxy glass cloth plate.
7. The tab insulation structure for dry-type transformer according to claim 1, wherein the spacer (51) is made of epoxy glass cloth plate or silicone plate.
8. A tab insulation structure for a dry-type transformer as claimed in claim 1, wherein said core leg is externally fitted with a transformer coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122084748.2U CN215644032U (en) | 2021-08-31 | 2021-08-31 | Pull plate insulation structure for dry type transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122084748.2U CN215644032U (en) | 2021-08-31 | 2021-08-31 | Pull plate insulation structure for dry type transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215644032U true CN215644032U (en) | 2022-01-25 |
Family
ID=79904978
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122084748.2U Active CN215644032U (en) | 2021-08-31 | 2021-08-31 | Pull plate insulation structure for dry type transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215644032U (en) |
-
2021
- 2021-08-31 CN CN202122084748.2U patent/CN215644032U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2011072432A1 (en) | Thyristor converter valve module | |
| CN203310894U (en) | Novel field winding all-fiber current transformer | |
| CN215644032U (en) | Pull plate insulation structure for dry type transformer | |
| CN209071068U (en) | A kind of waterproof durable type transformer | |
| CN215644058U (en) | Iron yoke insulation structure for oil-immersed transformer | |
| US8279033B2 (en) | Transformer with isolated cells | |
| CN213519518U (en) | High-safety iron core reactor structure | |
| CN208938762U (en) | A kind of oil-immersed transformer resistant to high temperature | |
| CN208835689U (en) | A kind of flame-resistant insulation bus duct | |
| CN215770822U (en) | Dry-type insulating transformer | |
| CN220895299U (en) | Air-cooled transformer | |
| CN221486228U (en) | Transformer with protective structure | |
| Marchio | Designing with the PLA51 planar transformer for enhanced power density and efficiency | |
| CN202585072U (en) | Insulating sound barrier for outdoor transformer | |
| CN209843474U (en) | Series-parallel connection multipurpose high-reliability power transformer | |
| CN212648050U (en) | Transformer with lightning protection function | |
| CN216528356U (en) | High security power transformer core subassembly | |
| CN217507068U (en) | Transformer winding structure | |
| CN109411190A (en) | A kind of waterproof durable type transformer | |
| CN221573626U (en) | Self-cooling transformer | |
| KR101494599B1 (en) | Auto molded transformer for an electric-railroad power supply | |
| CN214428462U (en) | Aviation power transformer with good heat dissipation performance | |
| CN220604473U (en) | High-voltage-grade dry-type transformer | |
| CN217061682U (en) | Dry-type transformer with good heat dissipation performance | |
| CN211181826U (en) | Dry-type transformer drip proof device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: A pull plate insulation structure for dry-type transformers Granted publication date: 20220125 Pledgee: Industrial Bank Co.,Ltd. Shanghai Minhang sub branch Pledgor: SHANGHAI NAIJI ELECTRIC POWER GROUP CO.,LTD. Registration number: Y2024310000045 |
|
| PE01 | Entry into force of the registration of the contract for pledge of patent right |