GB1578735A - Method and apparatus for making a sealing bellows - Google Patents
Method and apparatus for making a sealing bellows Download PDFInfo
- Publication number
- GB1578735A GB1578735A GB26128/76A GB2612876A GB1578735A GB 1578735 A GB1578735 A GB 1578735A GB 26128/76 A GB26128/76 A GB 26128/76A GB 2612876 A GB2612876 A GB 2612876A GB 1578735 A GB1578735 A GB 1578735A
- Authority
- GB
- United Kingdom
- Prior art keywords
- parison
- die
- sealing bellows
- bellows
- tool cavity
- 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.)
- Expired
Links
- 238000007789 sealing Methods 0.000 title claims description 42
- 238000000034 method Methods 0.000 title claims description 31
- 239000000463 material Substances 0.000 claims description 32
- 229920001169 thermoplastic Polymers 0.000 claims description 19
- 239000004416 thermosoftening plastic Substances 0.000 claims description 19
- 238000007664 blowing Methods 0.000 claims description 11
- 238000000071 blow moulding Methods 0.000 claims description 10
- -1 polyethylenes Polymers 0.000 claims description 9
- 239000004743 Polypropylene Substances 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- 229920001155 polypropylene Polymers 0.000 claims description 5
- 229920002635 polyurethane Polymers 0.000 claims description 5
- 239000004814 polyurethane Substances 0.000 claims description 5
- 239000004698 Polyethylene Substances 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 240000008100 Brassica rapa Species 0.000 claims description 2
- 238000001125 extrusion Methods 0.000 claims description 2
- 239000008187 granular material Substances 0.000 claims description 2
- 230000003301 hydrolyzing effect Effects 0.000 claims description 2
- 239000004033 plastic Substances 0.000 claims description 2
- 229920003023 plastic Polymers 0.000 claims description 2
- 238000009966 trimming Methods 0.000 claims description 2
- 229920001971 elastomer Polymers 0.000 description 3
- 238000000748 compression moulding Methods 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 125000000816 ethylene group Chemical class [H]C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
- B29C49/42—Component parts, details or accessories; Auxiliary operations
- B29C49/48—Moulds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J3/00—Diaphragms; Bellows; Bellows pistons
- F16J3/04—Bellows
- F16J3/041—Non-metallic bellows
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
- B29C49/42—Component parts, details or accessories; Auxiliary operations
- B29C49/48—Moulds
- B29C2049/4879—Moulds characterised by mould configurations
- B29C2049/4881—Moulds characterised by mould configurations having a mandrel or core e.g. two mould halves with a core in-between
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
- B29K2995/0026—Transparent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/703—Bellows
Description
(54) METHOD AND APPARATUS FOR MAKING A SEALING
BELLOWS
71) We, CAM GEARS LIMITED, a
British Company, of 45 Wilbury Way,
Hitchin, Hertfordshire SG4 OTU, do hereby declare the invention for which we pray that a Patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to a method and apparatus for making a flexible sealing bellows, which is particularly but not only, suitable for sealing the rack housing of a rack and pinion steering system.
In a rack and pinion steering system it is customary for the rack to extend through an elongate rack housing, the ends of the rack being coupled to suitable linkages for effecting the steering movement of the vehicle road wheels. The rack housing is sealed in order to prevent dirt from entering the housing and oil from leaving the housing. A convenient technique for effecting the sealing is to use a corrugated bellows having a larger end connected to the housing and an opposite smaller end connected to either rack or to the rods emanating from the rack ends. The advantage of a corrugated flexible bellows con struction is that it can contract and expand to accommodate the linear movement of the rack necessary to produce the required steering movement of the vehicle road wheels.
It has been previously proposed to manufacture the steering bellows by either compression moulding or injection moulding. With compression moulding a block of oil resistant rubber is compressed between heated inner and outer die members to form an appropriate shape for the bellows. With injection moulding, rubber at a high temperature and pressure is forced into a mould of the appropriate shape having a suitable core therein, and the rubber is then allowed to solidify. It is an aim of the invention to provide an improved rack sealing bellows, and a method of producing the bellows.
According to one aspect of the present invention, there is provided a method of forming a flexible sealing bellows, comprising passing particles of a suitable thermoplastics material along a thermally controlled feed device in which the material is melted, to a die defining a tubular die space, extruding the melted thermoplastics material through the die space to provide a parison, locating the paris on in a tool cavity defined by die members to have the required shape of the sealing bellows, and expanding the parison by blow moulding to take up the shape of the tool cavity.
Further according to the present invention there is provided a flexible sealing bellows made by the method described in the immediately preceding paragraph. The bellows may be made of any suitable material such as, for example, the ethylenes and the polypropylenes and a preferred material for the bellows is a polyurethane thermoplastics. Conveniently the bellows are formed to be at least partly translucent or transparent. In the commercial production of rack and pinion steering systems it is common practice to supply a vehicle manufacturer with the assembled system already filled with oil. Although it is customary for assembled gears to be inspected before being sent to a customer, there is of course a risk that a gear might pass through the inspection system and be sent out without its oil content. By providing at least partly translucent or transparent sealing bellows, such a risk is alleviated.
According to a further aspect of the invention, there is provided apparatus for forming a flexible sealing bellows comprising a thermally controlled feed device to extrude melted particles of a suitable thermoplastics material through a tubular die space to pro vide a parison, a tool cavity to receive the parison, said tool cavity being defined by die members to have the required shape of the sealing bellows, and means for expanding the parison in the tool cavity by blowing into the parison so that it takes up the shape of the tool cavity.
The parison may be expanded by sealing one end of the parison, nipping the other end
of the parison around a blow pipe communicating with the parison interior, and blowing air through the blow pipe into the parison to expand the parison. Conveniently the dimensions of the die space may be adjusted
to produce sealing bellows with desired wall
thicknesses, and where the die space is defined
by a die head extending into a hollow casing,
this may be done by adjusting the die head
with respect to the casing.
The invention will now be further des
cribed by way of example only, with reference
to the accompanying illustrative drawings, in
which:
FIGURE 1 is a side elevation of a rack
sealing bellows, and
FIGURE 2 and 3 are diagrammatic eleva
tions of different parts of one embodiment of
apparatus for blow-moulding the bellows of
FIGURE 1.
Referring to the drawings, granules of a
suitable thermoplastics material are loaded
into a hopper 2 and passed to a thermally
controlled feed device consisting of an Archi
median screw 4 extending along an elongate
barrel 6. On rotating the screw 4, the heated
and melted graules are passed along the feed
device to a die consisting of a die head 8 ex
tending into a hollow casing 10 to define a
tubular die space 12.
Referring to FIGURE 3, the die head 8
is vertically adjustable in the casing 10 to
vary the thickness of the wall of the extruded
tube or parison in the die space 12. The
melted thermoplastics material is extruded
through the die space 12 to provide a tube
or parison, and when this tube is of the re
quired length it is cut off and transported
downwardly into a temperature controlled tool cavity defined by two semi-tubular members 14.
A blow pipe 16 is inserted into the extruded rube or parison and rhe die members
14 are closed around the parison to pinch together the parison end 18 remote from the blow pipe to form a sealed end. The other end 20 of the parison is nipped tightly around the blow pipe 16 by the die members 14. Heated air is blown from the blow pipe 16 into the extruded tube thereby blowing out the tube which expands to take up the form of the die members 14 which are shaped in the required corrugated form of the sealing bellows.
The thermoplastics material at the opposite end of the tube to the blow pipe 16 is removed by a suitable trimming device, the blow pipe 16 is removed, and the die members 14 are withdrawn to release the formed sealing bellows. The thermoplastics material adjacent to the blow pipe 16 may be torn away by hand without damaging the formed bellows.
The tool cavity is then ready to receive the next extruded tube which has been formed with the die head.
A preferred material for the sealing bellows is a polyurethane plastics which is specially compounded for high strength and flexibility, and to be highly resistant to hydrolytic attack. However, polyethylenes or polypropylenes may be used. Preferably the thermoplastics material is such that the blowmoulded bellows are at least partly translucent or transparent.
An advantage of the blow moulding technique is that it can produce rack and sealing bellows at a higher speed than previously known methods.
Another feature of the blow moulding technique is that the die head can be easily and automatically adjusted during the extrusion process to produce an extruded tube, and hence a sealing bellows, of a desired varying wall thickness. This has the advantage that, after blowing out the parison to size, a more or less constant wall thickness can be maintained regardless of the blown diameters.
WHAT WE CLAIM IS:- 1. A method of forming a flexible sealing bellows comprising passing particles of a suitable thermoplastics material along a thermally controlled feed device in which the material is melted, to a die defining a tubular die space, extruding the melted thermoplastics material through the die space to provide a parison, locating the parison in a tool cavity defined by die members to have the required shape of the sealing bellows, and expanding the parison by blow moulding to take up the shape of the tool cavity.
2. A method as claimed in claim 1 including sealing one end of the parison, nipping the other end of the parison around a blow pipe communicating with the parison interior, and blowing air through the blow pipe into the parison to expand the parison.
3. A method as claimed in claim 1 or claim 2 which includes adjusting the dimensions of the die space to produce a sealing bellows of a desired wall thickness.
4. A method as claimed in any one of the preceding claims in which the material is selected from one or more of the polyethylenes.
5. A method as claimed in any one of claims 1 to 3 in which the material is selected from one or more of the polypropylenes.
6. A method as claimed in any one of claims 1 to 3 in which the material is selected from one or more of the polyurethanes.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (1)
- **WARNING** start of CLMS field may overlap end of DESC **.vide a parison, a tool cavity to receive the parison, said tool cavity being defined by die members to have the required shape of the sealing bellows, and means for expanding the parison in the tool cavity by blowing into the parison so that it takes up the shape of the tool cavity.The parison may be expanded by sealing one end of the parison, nipping the other end of the parison around a blow pipe communicating with the parison interior, and blowing air through the blow pipe into the parison to expand the parison. Conveniently the dimensions of the die space may be adjusted to produce sealing bellows with desired wall thicknesses, and where the die space is defined by a die head extending into a hollow casing, this may be done by adjusting the die head with respect to the casing.The invention will now be further des cribed by way of example only, with reference to the accompanying illustrative drawings, in which: FIGURE 1 is a side elevation of a rack sealing bellows, and FIGURE 2 and 3 are diagrammatic eleva tions of different parts of one embodiment of apparatus for blow-moulding the bellows of FIGURE 1.Referring to the drawings, granules of a suitable thermoplastics material are loaded into a hopper 2 and passed to a thermally controlled feed device consisting of an Archi median screw 4 extending along an elongate barrel 6. On rotating the screw 4, the heated and melted graules are passed along the feed device to a die consisting of a die head 8 ex tending into a hollow casing 10 to define a tubular die space 12.Referring to FIGURE 3, the die head 8 is vertically adjustable in the casing 10 to vary the thickness of the wall of the extruded tube or parison in the die space 12. The melted thermoplastics material is extruded through the die space 12 to provide a tube or parison, and when this tube is of the re quired length it is cut off and transported downwardly into a temperature controlled tool cavity defined by two semi-tubular members 14.A blow pipe 16 is inserted into the extruded rube or parison and rhe die members14 are closed around the parison to pinch together the parison end 18 remote from the blow pipe to form a sealed end. The other end 20 of the parison is nipped tightly around the blow pipe 16 by the die members 14. Heated air is blown from the blow pipe 16 into the extruded tube thereby blowing out the tube which expands to take up the form of the die members 14 which are shaped in the required corrugated form of the sealing bellows.The thermoplastics material at the opposite end of the tube to the blow pipe 16 is removed by a suitable trimming device, the blow pipe 16 is removed, and the die members 14 are withdrawn to release the formed sealing bellows. The thermoplastics material adjacent to the blow pipe 16 may be torn away by hand without damaging the formed bellows.The tool cavity is then ready to receive the next extruded tube which has been formed with the die head.A preferred material for the sealing bellows is a polyurethane plastics which is specially compounded for high strength and flexibility, and to be highly resistant to hydrolytic attack. However, polyethylenes or polypropylenes may be used. Preferably the thermoplastics material is such that the blowmoulded bellows are at least partly translucent or transparent.An advantage of the blow moulding technique is that it can produce rack and sealing bellows at a higher speed than previously known methods.Another feature of the blow moulding technique is that the die head can be easily and automatically adjusted during the extrusion process to produce an extruded tube, and hence a sealing bellows, of a desired varying wall thickness. This has the advantage that, after blowing out the parison to size, a more or less constant wall thickness can be maintained regardless of the blown diameters.WHAT WE CLAIM IS:- 1. A method of forming a flexible sealing bellows comprising passing particles of a suitable thermoplastics material along a thermally controlled feed device in which the material is melted, to a die defining a tubular die space, extruding the melted thermoplastics material through the die space to provide a parison, locating the parison in a tool cavity defined by die members to have the required shape of the sealing bellows, and expanding the parison by blow moulding to take up the shape of the tool cavity.2. A method as claimed in claim 1 including sealing one end of the parison, nipping the other end of the parison around a blow pipe communicating with the parison interior, and blowing air through the blow pipe into the parison to expand the parison.3. A method as claimed in claim 1 or claim 2 which includes adjusting the dimensions of the die space to produce a sealing bellows of a desired wall thickness.4. A method as claimed in any one of the preceding claims in which the material is selected from one or more of the polyethylenes.5. A method as claimed in any one of claims 1 to 3 in which the material is selected from one or more of the polypropylenes.6. A method as claimed in any one of claims 1 to 3 in which the material is selected from one or more of the polyurethanes.7. A method as claimed in any one of thepreceding claims in which the material is such that the blow-moulded bellows is at least partly translucent or transparent.8. A method of forming a flexible sealing bellows substantially as herein described with reference to the accompanying drawings.9. A flexible sealing bellows made by a method as claimed in any one of the preceding claims.10. Apparatus for forming a flexible sealing bellows comprising a thermally controlled feed device to extrude melted particles of a suitable thermoplastics material through a tubular die space to provide a parison, a tool cavity to receive the parison, said tool cavity being defined by die members to have the required shape of the sealing bellows, and means for expanding the parison in the tool cavity by blowing into the parison so that it takes up the shape of the tool cavity.11. Apparatus as claimed in claim 10 in which the expanding means comprises means to close both ends of the parison with a blow pipe communicating with the parison interior and to blow air into the closed parison.12. Apparatus as claimed in claim 10 or claim 11 in which the die space is defined by a die head extending into a hollow casing.13. Apparatus as claimed in claim 12 in which the die head is adjustable with respect to the casing to vary the wall thickness of the parison.14. Apparatus for blow moulding a flexible sealing bellows substantially as herein described with reference to the accompanying drawings.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB26128/76A GB1578735A (en) | 1976-06-23 | 1977-05-24 | Method and apparatus for making a sealing bellows |
| FR7716419A FR2356062A1 (en) | 1976-06-23 | 1977-05-27 | PROCESS FOR MANUFACTURING SEALING BELLOWS, APPARATUS FOR THEIR MANUFACTURING AND BELLOWS OBTAINED |
| IT2487877A IT1078305B (en) | 1976-10-14 | 1977-06-21 | Moulding see=through bellows seals for steering mechanisms - for visual detection of internal lubricant loss |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2621876A GB1553866A (en) | 1975-06-24 | 1976-06-23 | Construction of wall for a building and method of constructing the wall |
| GB4270376 | 1976-10-14 | ||
| GB26128/76A GB1578735A (en) | 1976-06-23 | 1977-05-24 | Method and apparatus for making a sealing bellows |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1578735A true GB1578735A (en) | 1980-11-05 |
Family
ID=27258496
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB26128/76A Expired GB1578735A (en) | 1976-06-23 | 1977-05-24 | Method and apparatus for making a sealing bellows |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR2356062A1 (en) |
| GB (1) | GB1578735A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009003892A1 (en) * | 2007-07-03 | 2009-01-08 | Special Springs S.R.L. | Guard for gas cylinder actuators |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2513568B1 (en) * | 1981-09-30 | 1986-03-14 | Kyoraku Co Ltd | ELASTIC SHAPE ARTICLE WITH POLYVINYL CHLORIDE LAYER |
| EP0093937A1 (en) * | 1982-05-10 | 1983-11-16 | Clinton E. Grove | Covering for rotating flexible axle joints |
| FR2554386B1 (en) * | 1983-11-07 | 1986-02-07 | Plastic Omnium Cie | METHOD FOR MANUFACTURING PROFILED TUBES IN PLASTIC MATERIAL, DEVICE FOR CARRYING OUT SAID METHOD, AND PROFILED TUBES OBTAINED |
| FR2596693B1 (en) * | 1986-04-04 | 1988-10-14 | Ouest Cie | METHOD AND DEVICE FOR INJECTION-BLOWING HOLLOW BODY WITH TWO THERMOPLASTIC COMPONENTS AND HOLLOW BODY THUS OBTAINED |
-
1977
- 1977-05-24 GB GB26128/76A patent/GB1578735A/en not_active Expired
- 1977-05-27 FR FR7716419A patent/FR2356062A1/en active Granted
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009003892A1 (en) * | 2007-07-03 | 2009-01-08 | Special Springs S.R.L. | Guard for gas cylinder actuators |
| EP2570712A1 (en) * | 2007-07-03 | 2013-03-20 | Special Springs S.r.l. | Guard for gas cylinder actuators |
| EP2160538B1 (en) | 2007-07-03 | 2015-06-24 | Special Springs S.r.l. | Gas cylinder actuators comprising a guard |
| US9133984B2 (en) | 2007-07-03 | 2015-09-15 | Special Springs S.R.L. | Guard for gas cylinder actuators |
| EP2963331A1 (en) * | 2007-07-03 | 2016-01-06 | Special Springs S.r.l. | Gas cylinder actuators comprising a guard |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2356062A1 (en) | 1978-01-20 |
| FR2356062B3 (en) | 1980-02-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3035302A (en) | Extrusion and forming of plastic tubing | |
| US2575138A (en) | Method and apparatus for packaging and package | |
| US2975473A (en) | Manufacture of hollow plastic articles | |
| US3309443A (en) | Plastic molding | |
| US2787023A (en) | Manufacture of bottles and the like from plastic materials | |
| YU48087A (en) | Device for producing ribbed tubes | |
| GB1578735A (en) | Method and apparatus for making a sealing bellows | |
| NZ337074A (en) | An apparatus and a method for producing an extruded hollow plastic section to be supported and guided by the extrusion apparatus | |
| US3514468A (en) | Method of producing oriented crystalline plastics | |
| EP0445592B1 (en) | Method of making a hollow article out of foam material | |
| IE40830B1 (en) | Process and preform-moulding apparatus for the production of oriented hollow thermoplastic material articles | |
| US2898633A (en) | Method of forming hollow plastic articles | |
| CA2215947A1 (en) | Process and device for extruding plastic melts to form hollow bodies | |
| US2935764A (en) | Method for blowing plastic bottles | |
| GB2031330A (en) | Moulding pipes | |
| GB2295349A (en) | Extruding curved pipes | |
| AU7085587A (en) | A method and an apparatus for the production of ribbed pipes | |
| JPS5736628A (en) | Method and apparatus for molding pipelike substance | |
| JPS6330850B2 (en) | ||
| GB1119855A (en) | Apparatus and method for the manufacture of plastics containers by the blowing method | |
| IE37791L (en) | Gorrugated plastics pipe with holes | |
| RU2762305C2 (en) | Method and device for manufacturing insert for composite vessel used under pressure | |
| GB1280863A (en) | Method and apparatus for the manufacture of hollow articles from thermoplastics | |
| US3256377A (en) | Extrusion of thermoplastic tubes | |
| GB1207448A (en) | Extrusion apparatus for the production of tubes and tubular films of synthetic organic thermoplastic polymeric material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |