WO2006093498A1

WO2006093498A1 - Shock absorbent end cap for trays

Info

Publication number: WO2006093498A1
Application number: PCT/US2005/006890
Authority: WO
Inventors: Robert J. White, Jr.
Original assignee: Peak International, Inc.
Priority date: 2005-03-02
Filing date: 2005-03-02
Publication date: 2006-09-08

Abstract

In one embodiment of the present invention, an end cap is provided in the form of a box with an open top, having a substantially rectangular base and four substantially rectangular sides, each attached to one of four corresponding edges of the base. Th cap open top has interior length and width dimensions providing clearance for a corresponding width and height respectively of a stack of trays. A depth of the inside of the end cap allows insertion of a terminal end of a stack of trays. The end cap is constructed from a shock, absorbent material of thickness and material properties designed to absorb shock for the purpose of protecting the trays and components in the trays. Shock absorbing end caps are placed over both ends of a stack of trays, and the assembly is placed in a dry-pack bag and sealed, and then placed in a cardboard box for transportation.

Description

SHOCKABSORBENT END CAP FORTRAYS

BACKGROUND OF THEINVENTION

FIELD OF THE INVENTION

[0001] The present invention relates to methods and apparatus for protecting a stack of trays and the components stored therein, such as semiconductors. More particularly the invention relates to a shock absorbing end cap that fits over terminal ends of a stack of trays.

DESCRIPTION OF THE RELATED ART

[0002] Trays for storing and transporting small components such as semiconductors are generally stacked in quantities of two or more trays. The stack is then secured by wrapping it, for example with straps, or/and secured with end caps. For transportation, the stack is placed in a box, surrounded with shock absorbing material such as foam or bubble wrap, etc. The addition of foam or bubble wrap requires larger boxes, which consume more storage space, which is a disadvantage. On occasion, the stacks are boxed with inadequate shock absorbing material, resulting in damage to the trays and components in the process of handling and transportation.

SUMMARY

[0003] It is an advantage of the present invention that it allows smaller sized boxes to be used in the transport and storage of stacks of trays.

[0004] It is a further advantage of the present invention in that shock absorbing packaging material is not generally required to assure protection during handling and transportation of stacks of trays.

[0005] The above advantages, among others, can be achieved singly or in combination. [0006] In one embodiment of the present invention, an end cap is provided in the form of a box with an open top, having a substantially rectangular base and four substantially rectangular sides, each attached to one of four corresponding edges of the base. The end cap open top has interior length and width dimensions providing clearance for a corresponding width and height respectively of a stack of trays. A depth of the inside of the end cap allows insertion of an end portion of the stack of trays. The end cap is constructed from a shock absorbent material of thickness and material properties designed to absorb shock for the purpose of protecting the trays and components in the trays. Shock absorbing end caps are placed over both ends of a stack of trays, and the assembly is placed in a dry-pack bag and sealed, and then placed in a cardboard box for transportation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Fig. 1 shows an end cap according to the present invention;

[0008] Fig. 2 illustrates end caps installed on ends of a stack of trays according to a method of the present invention;

[0009] Fig. 3 is a cross sectional view showing a stack of trays with end caps, installed in a box for storage or shipment;

[00010] Fig. 4 A illustrates an end cap constructed of shock absorbing and non- shock absorbing materials; and

[00011] Fig. 4B is a cross sectional view of Fig. 4A.

[00012] Fig. 5 A illustrates an end cap having a plurality of ribs in accordance with the present invention.

[00013] Fig. 5B illustrates another feature of the end cap of Fig. 5A.

[00014] Fig. 6 illustrates an angled resilient structure incorporated into a portion of the walls of the end cap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS [00015] Fig. 1 shows an end cap 10 according to the present invention, in the form of a box-like structure having a substantially rectangular base 12, and four walls 14, 16, 18 and 20, each extending from an edge of the base to an open end 22. The end cap 10 forms a cavity 24, and is for placement over an end portion of a stack of trays. The end cap 10 is constructed of shock absorbing material, such as rubber or any of various other materials for the purpose of absorbing shock that will be understood by those skilled in the art. The calculations for determining the optimum material and thickness will be understood by those skilled in the art, and need not be described for any particular sizes and weights in order for the present invention to be understood and implemented. A shock absorbing material by definition in the present disclosure includes materials that will be recognized by those skilled in the art for such a purpose, and is generally a compressible, and somewhat resilient material, in contrast to relatively non-compressible materials such as hard plastic and metal.

[00016] The shape of the end cap 10 as shown in Fig. 1 is given by way of example. Various other shapes that conform to the shape at an end of a stack of trays will also be effective for the purpose, as should be understood by reading the present disclosure.

[00017] Fig. 1 shows protrusions 28 and 30 of shock absorbing material extending from the back wall 12 into the cavity 24, for the purpose of supporting the more substantial end portion of a tray on each side of an elongated tab-like protrusion that is often included on a molded tray. The cap 10 as shown in Fig. 1 has enhanced material thickness at the corners 32 and 34, giving added protection to the more vulnerable/fragile corners of the trays.

[00018] Fig. 2 illustrates the method of the present invention wherein an end cap 10 is placed over each of the two ends of a stack 36 of trays. Although two trays, or a tray and cover are symbolically illustrated as items 38 and 40, the present invention includes end caps designed for use on stacks of any number of trays and tray covers. Fig. 2 also shows the alternative protrusions 28 and 30, dimensional to give support to the end portions of the trays and to provide clearance for and therefore protect the elongated tab extension/protrusion 44. [00019] Fig. 3 is a cross sectional view of an assembly of a stack 46 of trays or trays and cover, with shock absorbent end caps 10, enclosed in a box 48 for storage or transportation/shipment. End portions 42 of the trays are clearly shown in Fig. 3.

[00020] Figs. 4A and 4B illustrate an alternate embodiment end cap 50 including an inner layer 52 constructed of any of various materials, such as a rigid or semi-rigid plastic, configured for installation over an end portion of a stack of trays in the same manner as shown in Fig. -2 illustrating the use of end caps 10. The inner layer 52 is at least partially covered with an outer layer of shock absorbing material 54, such as an elastomeric material. As a still further embodiment, the inner layer 52 can be constructed from a shock absorbing material, and the outer layer 54 can be a rigid material. In this latter case, the outer layer 54 serves the function of distributing an impact over a larger area of the shock absorbing material of the end cap 50. The structure of Figs. 4A and 4B is illustrative of the concept of the present invention, and one alternate embodiment. Those skilled in the art will understand a variety of variations in design from reading the present disclosure, and these are also included in the present invention. For example, the end cap 50 may be any of a variety of shapes, and in the case when the inner layer 52 is rigid material, shock absorbing material can also be of various configurations, such as separated components of material placed at various places, for example only on the corners or edges of the inner layer 52, instead of over the entire base and a substantial portion of the sidewalls that make up the outer layer 54 as described previously.

[00021] Alternative configurations of the back wall 12 for supporting the tray in general are also part of the present invention. For example, the end caps may include a resilient structure molded into back wall 12 (the base of the end cap) to absorb the impact of any shock to the tray stack. Fig. 5 A illustrates one such tray wherein the resilient structure comprises a plurality of curved ribs 51 adjacent to one another on one surface of wall 12. The surface opposite of the ribs is indented to provide a more uniform thickness along back wall 12, resulting in a scalloped edge 59 on a second surface of wall 12. In a more preferred embodiment, the end cap of Fig. 5 A will also have ribs along the interior of sidewalls 14, 16. In addition, Fig. 5B illustrates a narrow protrusion 45 that may extend along wall 20, as well as wall 18 to further protect the contents of the trays from shock. The end caps shown in Figures 5 A and 5B are preferably formed out of a rubber shock absorbing material, such as for example Kraton® rubber manufactured by Kraton Polymers. Any other thermoplastic rubber with similar elastic properties as Kraton® rubber would be suitable for manufacturing the end cap shown in Figures 5 A and 5B.

[00022] Yet another alternative end cap having a resilient structure molded into back wall 12 is shown in Fig. 6. End cap 100 includes a resilient structure having a plurality of angled portions 72A and 72B integrally molded into the base. The plurality of angled portions include a first set of portions extending at a first angle and a second set of portions extending at a second angle on said base. Angle 60 of the angled portions preferably ranges from 150° - 170°.

[00023] Each of the first set of portions converges with one of the second set of portions within the cavity to form apexes 75. When a stack of trays are inserted into end cap 100 the terminal ends of the trays contact apexes 75-1, 75-2, 75-3, 75-4 and 75-5. Apexes 75-1 through 75-5 deflect outward due to the presence of slits 81 at predetermined positions on wall 12 and on walls 14 and 16. Thus slits 81 impart spring-like characteristics to apexes 75-1 through 75-5, thereby minimizing any damage that maybe caused during testing, shipping, or handling of the trays. Each apex 75 is independently deformable, and securely maintain the end caps on the trays. Slits 81 are preferably provided on one or more of the first set of portions and on one or more of the second set of portions to enhance the flexibility of the base. It is believed that the end caps would be sufficiently shock absorbent if slits 81 and angled portions 72 were omitted from walls 14 and 16. However, in a preferred embodiment, angled portions 72 and slits 81 are also present on walls 14 and 16.

[00024] The end cap of Fig. 6 is preferably formed out of a polymeric material. In a preferred embodiment, the end caps of Fig. 6 are formed of either polypropylene or carbon-filled polypropylene. The end caps may also be formed of any other plastic material having similar elongation properties as polypropylene or carbon-filled polypropylene.

[00025] While the present invention has been described herein with reference to particular embodiments thereof, a latitude of modifications, various changes and substitutions are intended in the foregoing disclosure, and it will be appreciated that in some instances some features of the invention will be employed without a corresponding use of other features without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. An apparatus for protecting an end of a stack of trays comprising: an end cap constructed of material including a shock absorbing material, the end cap including a base having a perimeter that conforms to a shape of the end of the stack of trays; side walls connected to and extending from the perimeter of the base thereby forming a cavity within which the end of the stack can be inserted.

2. An apparatus as recited in claim 1 wherein the perimeter has a rectangular shape.

3. An apparatus as recited in claim 1 wherein the side walls includes four connected wall sections each connected to a base, each wall section interconnected at substantially right angles to an adjacent wall section, thereby forming an end cap of substantially rectangular box shape with an open top.

4. An apparatus as recited in claim 3 wherein the end cap is a unitary structure.

5. An apparatus as recited in claim 4 wherein the end cap is formed from a material comprising polypropylene or polypropylene having a carbon filling.

6. An apparatus as recited in claim 1, wherein the base has at least two protrusions extending into the cavity of the end cap.

7. An apparatus as recited in claim 5 further including a plurality of openings in the base, the plurality of openings adapted to facilitate removal of the end cap from the stack of trays.

8. An apparatus as recited in claim 1 further including a resilient structure integrally molded into the end cap.

9. An apparatus as recited in claim 8, wherein the resilient structure is integrally molded into the base of the end cap.

10. An apparatus for protecting an end of a stack of trays comprising: an end cap constructed of material including a shock absorbing material, the end cap including a base having a perimeter that conforms to a shape of the end of the stack of trays; a resilient structure integrally molded into the base; side walls connected to and extending from the perimeter of the base thereby forming a cavity within which the end of the stack can be inserted.

11. The apparatus of claim 10 wherein the resilient structure comprises angled portions on said base.

12. The apparatus of claim 11 wherein the end cap is formed of polypropylene or polypropylene filled with carbon.

13. The apparatus of claim 12 wherein the resilient structure comprises a plurality of angled portions, said plurality of angled portions including a first set of portions extending at a first angle and a second set of portions extending at a second angle on said base.

14. The apparatus of claim 13, wherein an opening is provided in one or more of said first set of portions and in one or more of said second set of portions.

15. The apparatus of claim 14, wherein each of said first set of portions converges with one of a second set of portions within the cavity to form apexes that contact the ends of the trays.

16. The apparatus of claim 10 wherein the resilient structure comprises a plurality of curved ribs adjacent to one another.

17. The apparatus of claim 16 wherein the end cap is formed of a thermoplastic rubber material.

18. The apparatus of claim 12 further comprising a resilient structure integrally molded onto at least a portion of the sidewalls on an interior of the cavity.

19. The apparatus of claim 18 wherein the resilient structure comprises a plurality of curved ribs adjacent to one another.

20. A method of protecting a stack of trays comprising: placing first and second shock absorbing end caps over respective first and second opposing ends of the stack of trays, wherein each of the first and second end caps have a resilient-structure on their respective bases, each of said end caps being unitary structures constructed of a material including shock absorbing material that each envelope the first and second opposing ends of the stack of trays in a cavity.

21. The method according to claim 20 further comprising the step of removing each of the first and second shock absorbing end caps.