1. A method for rotation molding an article, comprising the steps of:
introducing a first flowable material into a mold having an insulating member mounted on a mold wall and having a protrusion extending through an aperture in the mold wall;
heating and rotating the mold so as to lay down the first material as a first layer having a thickness small enough so as to form a gap at the insulating member;
removing the insulating member so as to expose the gap;
introducing a second flowable material without opening the mold;
heating and rotating the mold so as to fully cure the second material as a second layer over the first layer and in the gap;
cooling the mold so as to solidify both the first and second layers,
where the second material is introduced into the mold through the aperture.
2. The method of claim 1 where the mold does not cool appreciably between the first and second heating operations.
3. The method of claim 1 where the first heating operation does not fully cure the first material.
4. The method of claim 3 where the first material fully cures during the second heating operation.
5. The method of claim 1 where at least one of the rotation operations is biaxial.
6. The method of claim 1 where all of the operations are performed in the order listed.
7. The method of claim 1 where the first material is a plastic resin.
8. The method of claim 7 where the first heating operation does not sinter the first material.
9. The method of claim 1 where the second material is a plastic resin.
10. The method of claim 9 where the second layer bonds to the first layer.
11. The method of claim 10 where the first and second layer bond integrally, without a perceptible joint.
12. The method of claim 1 where the second layer is transparent.
13. The method of claim 12 where the aperture forms an elongated sight line.
14. The method of claim 13 where the aperture runs substantially vertically when the article is in an upright position.
15. The method of claim 1 where the insulating member has a low thermal conductivity.
16. The method of claim 15 where the insulating member is made of a fluorocarbon.
17. The method of claim 1 further comprising covering the aperture in the mold wall before the second heating operation.
18. The method of claim 17 where the aperture in the mold wall is covered with a cover member having a high heat conductivity.
19. A method for forming a plastic container having a transparent sight line for measuring the level of a substance in the container, the method comprising:
introducing a first plastic material into a mold having an elongated insulating member in a position desired for the sight line, the insulating member mounted on a mold wall and having a protrusion extending through a slot in the mold wall to minimize buildup of the first plastic material thereon, where the insulating member is removable from outside of the mold, without opening the mold;
heating and rotating the mold so as to partially cure the first material as an outside layer on the mold wall with a gap at the protrusion;
removing the insulating member so as to expose the slot and the gap;
introducing a second, transparent plastic material into the mold through the slot when the insulating member is removed;
covering the slot;
heating and rotating the mold so as to distribute the second material as an inside layer over the outside layer and in the gap, and so as to fully cure both the first and second materials;
cooling the mold and releasing the container therefrom.
20. The method of claim 19 where the first heating and rotating operation is sufficient to distribute the first material on the mold wall, but does not sinter it.
21. The method of claim 20 where the second material sinters during the second heating operation.
22. The method of claim 19 where the mold is not cooled between the first and second heating operations.
23. The method of claim 19 where the insulating member does not contact any opposing portion of the mold wall spaced away from the slot.
24. The method of claim 19 where the insulating member resists buildup of the first material thereon.
25. The method of claim 19 where the insulating member is at least partially fabricated of a fluoropolymer.
26. The method of claim 19 where the insulating member has a low thermal conductivity.
27. The method of claim 19 where the slot is covered with a cover member attachable to the mold without opening it.
28. The method of claim 27 where the cover member is substantially flush with the inside of the mold wall in the region of the slot.
29. The method of claim 19 where the total thickness of the wall of the article in the region of the sight line is greater than about 80% of a nominal total thickness of the article wall in other regions thereof.
30. The method of claim 19 where the second heating operation bonds the inside layer to the outside layer.
31. The method of claim 1, further comprising covering the gap after introducing the second flowable material.
32. The method of claim 31 where the gap is covered by a member having a high heat conductivity.
33. The method of claim 31 where the gap is covered by attaching a member to the mold from outside the mold.
34. The method of claim 31 where the gap is covered by a member having a protrusion flush with an inside surface of a wall of the mold.
35. The method of claim 31 where the second layer is transparent.
36. The method of claim 35 where the aperture forms an elongated sight line.
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 storage system comprising:
rows and columns of pairs of spaced-apart supports;
a plurality of trays, each supported at opposite ends by one of the pair of spaced-apart supports; and
a plurality of tubs removably secured to a first subset of the plurality of trays.
2) The system of claim 1 wherein the plurality of trays each include a plurality of ribs extending transversely to a bottom wall.
3) The system of claim 2 wherein the plurality of trays each include a connector protruding upward from the bottom wall.
4) The system of claim 3 wherein the plurality of tubs each include a connector complementary to the connector on each of the plurality of trays.
5) The system of claim 4 wherein the plurality of tubs each include a pair of opposed first walls extending upward from a bottom wall, each tub further including a pair of opposed second walls that are each significantly shorter than the first walls.
6) The system of claim 5 wherein each tub further includes a lip protruding outwardly from an upper edge of the first walls and the second walls.
7) The system of claim 6 wherein the plurality of tubs are thermoformed.
8) The system of claim 4 wherein the connectors on the trays are recessed relative to the plurality of ribs.
9) The system of claim 8 wherein the connectors on the tubs protrude downward from the bottom wall.
10) The system of claim 9 wherein the connectors on the tubs include openings through the bottom wall.
11) The system of claim 1 wherein the tubs each include a bottom wall having a single wall thickness and without ribs.
12) The system of claim 11 wherein the plurality of tubs are thermoformed.
13) A tub and tray assembly comprising:
a tray including a plurality of reinforcement members; and
a tub removably secured to the tray.
14) The tub and tray assembly of claim 13 wherein the plurality of reinforcement members include support ribs that extend upward from a bottom wall of the tray and wherein the tub is supported on outer, free ends of the plurality of support ribs.
15) The tub and tray assembly of claim 14 wherein the tray includes a connector protruding upward from the tray.
16) The tub and tray assembly of claim 15 wherein the tub includes a connector complementary to the connector on the tray.
17) The tub and tray assembly of claim 16 wherein the connector on the tray is recessed relative to the support ribs.
18) The tub and tray assembly of claim 17 wherein the tub includes a pair of opposed first walls extending upward from a bottom wall, the tub further including a second wall that is significantly shorter than the first walls.
19) The tub and tray assembly of claim 18 wherein the tub further includes a lip protruding outwardly from an upper edge of the first walls and the second wall.
20) The tub and tray assembly of claim 19 wherein the tub is thermoformed.
21) The tub and tray assembly of claim 18 wherein the connector on the tub protrudes downward from the bottom wall.
22) The tub and tray assembly of claim 21 wherein the connector on the tub includes an opening through the bottom wall.
23) The tub and tray assembly of claim 22 wherein the opening includes a large portion and a small portion, the large portion larger than the connector on the tray, the small portion smaller than the connector on the tray.
24) The tub and tray assembly of claim 13 wherein the tub includes a single bottom wall without ribs.
25) A container comprising:
a bottom wall having a plurality of openings therethrough, at least one of the openings including a large portion and a contiguous small portion;
a pair of opposed first walls extending upward from the bottom wall; and
a pair of opposed second walls extending upward from the bottom wall.
26) The container of claim 25 wherein at least one of the second walls significantly shorter than the first walls.
27) The container of claim 25 wherein the container is thermoformed.
28) The container of claim 25 wherein the bottom wall is a single wall without ribs.
29) The container of claim 25 further including a lip protruding outwardly from an upper edge of the first walls and the second walls.
30) The container of claim 25 wherein the first walls and the second walls are angled away from one another, such that a similar container could be received therein.
31) The container of claim 25 wherein the bottom wall includes a flange portion around the large portion and the small portion of the at least one opening, the flange portion protruding downward from the bottom wall.
32) A method for making a storage system including the steps of:
forming a tub having a bottom wall and a pair of opposed walls;
forming a tray having a plurality of reinforcement members and at least one connector adapted to removably connect the tray to the tub; and
removably securing the tub to the tray via the at least one connector.
33) The method of claim 32 wherein said step a) includes the step of thermoforming the tub.
34) The method of claim 32 wherein said step a) includes the step of forming the bottom wall without ribs.
35) The method of claim 34 wherein said step a) further includes the step of forming at least one opening through the bottom wall, the at least one opening adapted to connect to the at least one connector of the tray.