Method for stacking receptacles

The invention, in one embodiment, is a method for stacking receptacles. The method comprises stacking a first receptacle on a second receptacle; and inverting the stacked first and second receptacles to engage the first and second receptacles.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to a receptacle and, more particularly, to 
a method for stacking receptacles. 
2. Description of the Related Art 
Stackable receptacles are commonly used in many areas of industry. One such 
use is the handling of electronic components during their manufacture, 
shipment, and assembly into computers. For instance, when a personal 
computer manufacturer receives electronic components, the components may 
be tested before their assembly into personal computers. The tested 
components are then placed into receptacles called "trays." The trays are 
stacked as they are filled. Finally, stacks of trays are moved to 
transport the tested components to their destinations in the assembly 
facility. 
These stacks of trays containing electronic components are frequently 
vulnerable to spillage. A stack may be unstable because individual trays 
do not mate well or are stacked too high. Also, a stack may be knocked 
over while colliding with another stack, a piece of machinery, or even a 
passing pedestrian. Stabilizing measures may be taken to help prevent 
spillage. For instance, a rubber band or a strap might be wrapped around 
the stack. However, rubber bands and straps may be difficult to apply and 
may be prone to breaking in some contexts. 
Some stabilizing measures interlock the stacked trays to achieve greater 
stability. Exemplary interlocking, stabilized receptacles are disclosed, 
for instance, in U.S. Pat. Nos. 1,137,759; 2,561,561; 3,259,263; and 
4,293,072. Each of these receptacles employs interlocking stabilizing 
measures that are difficult to use, or time-consuming, or both. For 
instance, U.S. Pat. No. 1,137,759 teaches stacking of folding boxes using 
U-shaped retaining clips along the bottom edges of the four sides of a 
box. The clips fall into position when stacking under the action of 
gravity to engage upper edge portions of the underlying box to interlock 
the boxes and prevent sliding movement. However, gravity will act to 
extend the clips before a box is actually stacked, thereby aggravating the 
difficulties in aligning the box for stacking. 
The present invention is directed to overcoming, or at least reducing the 
effects of, one or more of the problems set forth above. 
SUMMARY OF THE INVENTION 
The invention, in one embodiment, is a method for stacking receptacles. The 
method comprises stacking a first receptacle on a second receptacle; and 
inverting the stacked first and second receptacles to engage the first and 
second receptacles.

While the invention is susceptible to various modifications and alternative 
forms, specific embodiments thereof have been shown by way of example in 
the drawings and are herein described in detail. It should be understood, 
however, that the description herein of specific embodiments is not 
intended to limit the invention to the particular forms disclosed, but on 
the contrary, the intention is to cover all modifications, equivalents, 
and alternatives falling within the spirit and scope of the invention as 
defined by the appended claims. 
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
Illustrative embodiments of the invention are described below. In the 
interest of clarity, not all features of an actual implementation are 
described in this specification. It will of course be appreciated that in 
the development of any such actual embodiment, numerous 
implementation-specific decisions must be made to achieve the developers' 
specific goals, such as compliance with system-related and 
business-related constraints, which will vary from one implementation to 
another. Moreover, it will be appreciated that such a development effort, 
even if complex and time-consuming, would be a routine undertaking for 
those of ordinary skill in the art having the benefit of this disclosure. 
A First Embodiment of an Assembly of Stacked Receptacles 
FIG. 1 illustrates one embodiment of an assembly 10 of stackable 
receptacles 12a-c in accord with the present invention. The assembly 10 in 
the embodiment of FIG. 1 comprises three receptacles 12a-c, but the number 
of receptacles is not material to the practice of the invention. The 
receptacle 12a is in the process of being placed on the receptacle 12b 
that was previously stacked on the receptacle 12c. None of the receptacles 
12a-c is engaged with any other of the receptacles 12a-c in FIG. 1. 
The embodiment of the assembly 10 illustrated in FIG. 1 actually includes 
four points 15 of engagement between each of the receptacles 12a-c. The 
precise number of engagement points 15 is implementation specific and may 
be more or fewer than four. Each engagement point 15 is constructed using 
the slot and engaging member combination illustrated in FIG. 2 and 
discussed more fully below. However, in embodiments having more than one 
engagement point 15, the engagement points 15 may have differing 
constructions. 
FIG. 2 is a partial cross-section of the assembly 10 in FIG. 1 taken along 
the line 2--2 of FIG. 1. More particularly, FIG. 2 illustrates the 
relationship of the stacked receptacles 12b-c in cross-section. The 
receptacle 12b includes a first side 14 with a first slot 16 therein. The 
receptacle 12c includes a second side 18 with a second slot 20 therein. An 
engaging member 22 reciprocates within the second slot 20 to extend 
therefrom into the first slot 16 responsive to gravity to engage the 
receptacle 12b and the receptacle 12c as discussed in more detail below. 
Referring now to both FIGS. 1 and 2, the receptacles 12a-c in the 
particular embodiment illustrated are modular although this is not 
necessary to the practice of the invention. Each of the receptacles 12a-c 
has the same construction and is interchangeable with the others. More 
particularly each of the receptacles includes a body 25 having a first 
surface 14 and a second surface 18. The first surface 14 includes the 
first slot 16 obliquely disposed relative thereto. The second surface 18 
includes the second slot 20 obliquely disposed relative thereto in 
parallel relation to the first slot 16, the opening 40 of the second slot 
20 being vertically aligned with the opening 38 of the first slot 16 as 
best shown in FIG. 3A. As mentioned above, the engaging member 22 
reciprocates within the second slot 20. 
In the particular embodiment illustrated, the first and second receptacles 
12a and 12b include numerous characteristics that may be varied in 
alternative embodiments. More particularly: 
both the first surface 14 and the second surface 18 are quadrilaterally 
shaped. However, virtually any geometric shape may be employed and the 
first surface 14 and the second surface 18 may differ in shape; 
both the first and second surfaces 14 and 18 are continuous. In other 
embodiments, either, or both, of the first and second surfaces 14 and 18 
may be alternatively formed. For instance, the first and second surfaces 
may comprise the ends of legs in which the engagement points 15 may be 
formed. 
there are four engagement points 15, one in each corner of the 
quadrilaterally shaped surfaces 14 and 18. Alternative embodiments might 
employ only a pair of engagement points 15 that are horizontally displaced 
or placed in opposite corners. 
each body 25 is quadrilaterally shaped in horizontal cross-section although 
other geometric shapes may suffice and the body 25 of each receptacle 
12a-c may differ from one or more of the others. 
the first surfaces 14 parallel the second surfaces 18. As those in the art 
having the benefit of this disclosure will appreciate, still other 
variations on the particular embodiment might be employed in alternative 
embodiments. 
FIGS. 3A-3B and 4-5 illustrate the principles of engagement between the 
receptacle 12b and the receptacle 12c and the engagement points 15 in the 
embodiment of FIGS. 1-2. More particularly, FIGS. 3A-3B are fragmented 
views of the partial cross-section in FIG. 2. FIGS. 4-5 illustrate one 
embodiment of the engaging member 22 employed in the assembly 10 of FIG. 
1. 
The engaging member 22 is shown retracted into the slot 20 in FIG. 3A. As 
is apparent from FIGS. 4-5, the engaging member 22, in this particular 
embodiment, is a pin having a conical cross-section although this is not 
necessary to the practice of the invention. The engaging member 22, as 
shown best in FIG. 5, comprises a first part 24 having a first diameter 
D.sub.1 and a second part 28 having a second diameter D.sub.2 greater than 
the first diameter D.sub.1. The engaging member 22 at one end 32 is angled 
and at the other end 34 is flat. The angle .alpha. of the end 32 is not 
material to the practice of the invention and the end 32 may by flat like 
the end 34 in some embodiments. 
Returning to FIG. 3A, the slots 16 and 20 in the particular embodiment 
illustrated also have conical cross-sections as best shown in FIG. 4. The 
slots 16 and 20 are designed to accommodate the engaging member 22 without 
restricting its reciprocal movement. The slot 20 therefore has a diameter 
D.sub.2 ' slightly larger than the diameter D.sub.2 and the slot 16 has a 
diameter D.sub.1 ' slightly larger than the diameter D.sub.1. The openings 
38 and 40 of the slots 16 and 20, respectively, therefore also align when 
the receptacles 14 and 16 are stacked as is shown in both FIG. 2 and FIG. 
3A. 
This particular embodiment also includes a means for retaining the engaging 
member 22 in the slot 20 to help prevent loss of the engaging member 22. 
The engaging means illustrated in FIG. 4 is a rosette 42 comprised of a 
plurality of flexible tabs 44. The slot 20 includes a cutout 46 shown best 
in FIG. 3B into which the tabs 44 are displaced when the engaging member 
22 is forcibly inserted into the slot 20. When the engaging member 22 is 
extended as discussed more fully below, the shoulder 48 on the engaging 
member 22 defined by the differing diameters D.sub.1 and D.sub.2 will stop 
against the flexible tabs 44, thereby discouraging removal of the engaging 
member 22 from the slot 20. The design and construction of the rosette 42 
is well known in the art. 
As A Method of Stacking and Engaging the Receptacles 
Returning to FIG. 1, the receptacles 12a-c are first stacked. In the 
embodiment illustrated, stacking includes not only placing the receptacles 
12a-c one upon the other, but also first aligning them so that the lip 58, 
shown best in FIGS. 2 and 3A, of each receptacle mates with the shoulder 
60, shown best in FIG. 4, of the receptacle on which it is placed. 
However, in some alternative embodiments, alignment may be unnecessary if 
the receptacles are in some manner self-aligning. 
Once the receptacles 12a-c are stacked, they are inverted to engage the 
receptacles 12a-c. In the embodiment illustrated, the receptacles 12a-c 
have no lid or cover from the compartment to contain the contents. Thus, 
the receptacle 12a on the top of the stack is left empty and provides a 
lid for the receptacle 12b. The receptacle 12b likewise provides a lid for 
the receptacle 12c. In this manner, each receptacle provides a lid for the 
receptacle below it in the assembly 10. However, in embodiments in which 
the receptacles 12-12c have lids or covers, the top receptacle 12a may be 
filled. 
Inverting the stacked receptacles 12a-c engages the receptacles 12a-c as 
the engaging members 22 extend responsive to gravity as shown in FIGS. 
6-7. As shown in FIG. 7, the engaging member 22 of the receptacle 12a, now 
on the bottom after inversion, retracts when the assembly 10 is placed on 
the surface 60. The engaging members 22 of the receptacles 12b-c, however, 
do not retract and maintain the engagement of the receptacles 12a-c to 
secure the assembly 10. 
A Second Embodiment for an Engagement Point 
FIGS. 8-10 illustrate a second embodiment 15a of an engagement point 
including engaging member 62 alternative to the engaging member 22 of 
FIGS. 4-5. This particular embodiment of the engaging member 62 is 
quadrilateral rather than conical in cross-section, but is otherwise 
designed and constructed as is the engaging member 22. The slot 64, being 
designed to accommodate the engaging member 62, is also quadrilateral in 
cross-section and includes a rosette 66. The rosette 66 is quadrilateral, 
but is otherwise designed and constructed like the rosette 42 in FIGS. 
4-5. Although not shown, the mating receptacle will include a slot such as 
the slot 16 that is also quadrilateral in cross-section, but will be 
otherwise designed and constructed like the slot 16 in FIGS. 4-5. 
A Third Embodiment for an Engagement Point 
FIGS. 11-13 illustrate a third embodiment of an engagement point 15b. This 
particular embodiment is designed and constructed in the same manner as 
the embodiment of FIGS. 3A-5, except as noted. First, the retaining means 
of the embodiment in FIGS. 11-13 differs from that previously discussed. 
Instead of a rosette, the embodiment of FIGS. 11-13 includes a split, or 
C, ring 70 installed in a groove 72 that stops the extension of the 
engaging member 74. The split ring 70 is compressed enough to slide into 
the slot 76 over the first end 78 of the first part 80 of the engaging 
member 74. The split ring 70 is pushed down the first part 80 until it 
reaches the groove 72, whereupon it decompresses to install. Thereafter, 
the extension of the engaging member 74 is halted when the shoulder 82 
defined by the difference in the first diameter DD.sub.1 and the second 
diameter DD.sub.2 of the first part 80 and the second part 88, 
respectively, contacts the split ring 70. Second, the first end 78 is flat 
rather than angled. 
Remarks 
The particular embodiments disclosed above are illustrative only, as the 
invention may be modified and practiced in different but equivalent 
manners apparent to those skilled in the art having the benefit of the 
teachings herein. Furthermore, no limitations are intended to the details 
of construction or design herein shown, other than as described in the 
claims below. For instance, it is contemplated that some features of the 
three embodiments described herein, including, but not limited to, the 
retaining means and rosettes, may be combined in alternative ways to 
create still other embodiments in light of this disclosure. It is 
therefore evident that the particular embodiments disclosed above may be 
altered or modified and all such variations are considered within the 
scope and spirit of the invention. Accordingly, the protection sought 
herein is as set forth in the claims below.