1. A method for blow molding a workpiece, the method comprising the steps of:
(a) forming a parison having a wall of multiple layers of polymer including a barrier layer, and open ends, each end having a end surface extending around the periphery of the respective end;
(b) forming a mold comprising first and second sections enclosing a cavity, a pinch-off spaced outward from a bottom of the cavity, first and second zones arranged along parting planes between the sections in series with and outboard of the pinch-off, the first zone located between the pinch-off and the second zone and having a lateral dimension larger than a lateral dimension of the pinch-off and smaller than a lateral dimension of the second zone, and a third zone arranged along the parting lines and inboard of the pinch-off;
(c) closing the mold sections on the parison such that in the mold at each end of the parison, a first portion of each end surface is compressed against a second portion of the respective end surface;
(d) closing the mold sections further on the parison such that the barrier layer of the first portion and second portion of the end surface at each parison end are joined and welded mutually along a continuous seal line which starts in the third zone; and
(e) removing a formed part from the mold.
2. The method of claim 1 wherein step (d) further comprises:
closing the mold sections further on the parison such that the layers of the first portion and second portion of the end surface at each parison end are joined and welded mutually along the seal line.
3. The method of claim 1 wherein step (d) further comprises:
closing the mold sections on the parison at a first, relatively high speed until the first portion and second portion of surfaces at each end form a seal line and the two mold halves are a first predetermined distance apart.
4. The method of claim 3 wherein step (d) further comprises:
closing the mold sections further on the parison at a second speed that is slower than the first speed until the two mold sections are a second predetermined distance apart that is less than the first predetermined distance.
5. The method of claim 4 wherein step (d) further comprises:
closing the mold sections further on the hollow parison at a speed that is intermediate the first speed and the second speed.
6. The method of claim 1 wherein step (a) further comprises the step of extruding a hollow cylindrical tube, each end having an edge extending around a perimeter of a respective end of the tube.
7. The method of claim 1 further comprising:
closing the mold sections; and
shaping the parison to inner surfaces of the mold by injecting a fluid at elevated pressure into the mold, thereby forcing the parison against the inner surfaces of the mold.
8. The method of claim 1 wherein the first and second portions of the two barrier layers at the end surfaces are welded over at least a portion of the length of the seal line.
9. The method according to claim 1, wherein a formed part removed from the mold is a fuel tank.
10. The method of claim 1 wherein two sheets of polymer located at an end of the parison are sealed mutually to form the workpiece.
11. The method of claim 1 further comprising:
cooling an outer surface of the parison before closing the mold, the cooling being sufficient to change the viscosity of said outer surface relative to the viscosity of other layers in the parison.
12. A method for blow molding a workpiece, the method comprising the steps of:
(a) forming a parison having a wall of multiple layers of polymer including a barrier layer, and open ends, each end having a end surface extending around the periphery of the respective end;
(b) forming a mold comprising first and second sections enclosing a cavity, a pinch-off spaced from a bottom of the cavity by a transition having a width that decreases as distance from said bottom increases, first and second zones arranged along parting planes between the sections in series with and outboard of the pinch-off, the first zone located between the pinch-off and the second zone and having a lateral dimension larger than a lateral dimension of the pinch-off and smaller than a lateral dimension of the second zone, and a third zone arranged along the parting lines and inboard of the pinch-off;
(c) closing the mold sections on the parison such that in the mold at each end of the parison a first portion of each end surface is compressed against a second portion of the respective end surface;
(d) closing the mold sections further on the parison at a first, relatively high speed until the first portion and second portion of surfaces at each end form a seal line and the two mold halves are a first predetermined distance apart;
(e) closing the mold sections further on the parison at a second speed that is slower than the first speed until the two mold sections are a second predetermined distance apart that is less than the first predetermined distance;
(f) closing the mold sections further on the parison at a speed intermediate the first speed and the second speed until the barrier layer of the first portion and second portion of the end surface at each parison end are joined and welded mutually along a continuous seal line which starts in the third zone; and
(g) removing the workpiece from the mold.
13. The method of claim 12 wherein step (a) further comprises the step of extruding a hollow cylindrical tube having opposite ends, each end having a circumferential edge extending around a perimeter of a respective end of the tube.
14. The method of claim 12 wherein step (d) further comprises:
shaping the parison to the inner surfaces of the mold by injecting a fluid at elevated pressure into the mold, thereby forcing the parison against the inner surfaces of the mold.
15. The method of claim 12 wherein the first and second portions of the two barrier layer materials at the end surfaces are welded over at least a portion of the length of the seal line.
16. The method of claim 12, wherein the workpiece removed from the mold is a fuel tank.
17. The method of claim 12 wherein two sheets of polymer located at an end of the parison are sealed mutually to form the workpiece.
18. The method of claim 12 further comprising:
cooling an outer surface of the parison before closing the mold, the cooling being sufficient to change the viscosity of said outer surface relative to the viscosity of other layers in the parison.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of receiving and exposing user-generated lists of items, the method comprising:
providing, in association with an electronic catalog of items, a user interface that includes functionality for users to interactively create lists of items selected from the electronic catalog, and to submit the lists for viewing by other users;
receiving user-created lists of items, said user-created lists created and submitted by users via the user interface;
ranking, with one or more computer processors, at least one user-created list relative to other user-created lists based at least partly on effectiveness levels of the user-created lists as measured based on monitored user behaviors of users that access such user-created lists;
receiving a search query submitted by a user to conduct a search of the electronic catalog; and
selecting, with one or more computer processors, at least one user-created list to expose to the user with results of the search query, said selecting based at least partly on the search query and the ranking of the user-created lists.
2. The method of claim 1, wherein the effectiveness levels of the user-created lists are based at least partly on an observed tendency of users who view the user-created lists to subsequently purchase items.
3. The method of claim 1, wherein ranking the user-created lists comprises collecting and analyzing data reflective of a tendency of users who access particular user-created lists to thereafter select an item for purchase.
4. The method of claim 1, wherein selecting at least one user-created list to expose comprises:
identifying, by execution of the search query, a set of search result items; and
selecting the at least user-created list to expose based at least partly on the set of search result items.
5. The method of claim 4, wherein selecting at least one user-created list to expose comprises searching for user-created lists that include one or more of the search result items listed thereon.
6. The method of claim 4, wherein selecting at least one user-created list to expose comprises calculating degrees of similarity between the set of search result items and individual user-created lists.
7. The method of claim 4, wherein selecting at least one user-created list to expose comprises using item similarity data to identify user-created lists whose items are similar to one or more of the search result items.
8. The method of claim 1, further comprising generating, in response to the search query, a search results page that lists (1) catalog items that are responsive to the search query, and (2) the at least one user-created list selected to expose.
9. The method of claim 8, wherein the search results page includes, for each selected user-created list, a link for accessing the list and a textual description supplied by a creator of the list.
10. The method of claim 1, wherein the items include musical works.
11. Physical computer storage that stores executable code modules that direct an interactive computing system to perform a process that comprises:
providing, in association with an electronic catalog of items, a user interface that includes functionality for users to interactively create lists of items selected from the electronic catalog, and to submit the lists for viewing by other users;
receiving user-created lists of items, said user-created lists created and submitted by users via the user interface;
ranking at least one user-created list relative to other user-created lists based at least partly on effectiveness levels of the user-created lists as measured based on monitored user behaviors of users that access such user-created lists;
receiving a search query submitted by a user to conduct a search of the electronic catalog; and
selecting at least one user-created list to expose to the user with results of the search query, said selecting based at least partly on the search query and the ranking of the user-created lists.
12. An interactive system comprising one or more physical computers, said one or more computers configured to provide:
a user interface that includes functionality for users to interactively create lists of items selected from an electronic catalog, and to submit the lists for viewing by other users;
a data repository that stores user-created lists submitted by users via the user interface; and
a list selection system configured to select, from the data repository, one or more user-created lists to expose to a user based at least partly on
(1) a search query submitted by the user, and
(2) rankings of the user-created lists, said rankings based at least partly on effectiveness data reflective of effectiveness levels of particular user-created lists, as measured based on monitored behaviors of users that access such user-created lists.
13. The interactive system of claim 12, wherein the user interface provides at least one field for a list creator to enter a textual description of a list, and the interactive system is configured to expose the textual description to other users in conjunction with the list.
14. The interactive system of claim 13, wherein the one or more computers are additionally configured to expose to other users, in association with the list, creator-supplied information about the creator of the list.
15. The interactive system of claim 12, wherein the user interface provides item-specific fields for a list creator to enter textual comments regarding individual items on a list, and the interactive system is configured to expose the textual comments to users who access the list.
16. The interactive system of claim 12, wherein the effectiveness data is based at least partly on an observed tendency of users who access the user-created lists to subsequently acquire an item.
17. The interactive system of claim 12, wherein the list selection system is configured to rank the user-created lists based at least partly on the effectiveness data.
18. The interactive system of claim 12, wherein the list selection system is configured to select the one or more user-created lists to expose based at least partly on a set of search results items resulting from execution of the search query.
19. The interactive system of claim 18, wherein the list selection system is configured to use item similarity data to identify user-created lists that list at least one item that is similar to a search results item.
20. The interactive system of claim 18, wherein the list selection system is configured to measure degrees of similarity between the set of search result items and individual user-created lists.
21. The interactive system of claim 12, further comprising a server configured to generate, in response to the search query, a search results page that lists (1) items that are responsive to the search query, and (2) the one or more selected user-created lists.
22. The interactive system of claim 21, wherein the search results page includes, for each selected user-created list, a link for accessing the list and a textual description supplied by a creator of the list.
23. The interactive system of claim 12, wherein the list selection system is additionally configured to select, from the data repository, user-created lists to expose on item detail pages of the electronic catalog.