U.S. patent application number 10/620282 was filed with the patent office on 2005-01-20 for bare die tray clip.
Invention is credited to Bradley, Scott C., Pylant, James D., Waber, Alan.
Application Number | 20050011056 10/620282 |
Document ID | / |
Family ID | 34062747 |
Filed Date | 2005-01-20 |
United States Patent
Application |
20050011056 |
Kind Code |
A1 |
Pylant, James D. ; et
al. |
January 20, 2005 |
Bare die tray clip
Abstract
A clip is provided for holding a stack of at least one tray and
tray cover. Stack compressive, forces applied by the clip are
substantially limited to tray and cover perimeter rail portions.
The clip has a channel base with left and right side retaining
walls attached for restricting movement of a stack in left and
right directions. Left and right rods protrusions above the base
extend inward towards the walls of the channel from the left and
right side walls respectively for captivating the stack in an
upward direction. Spring protrusions extend upward from the base on
input and output ends of the channel, and are configured for
applying an upward spring force on opposing bottom edge areas of
the stack.
Inventors: |
Pylant, James D.; (Temecula,
CA) ; Bradley, Scott C.; (Carlsbad, CA) ;
Waber, Alan; (Wildomar, CA) |
Correspondence
Address: |
PILLSBURY WINTHROP LLP
2550 Hanover Street
Palo Alto
CA
94304
US
|
Family ID: |
34062747 |
Appl. No.: |
10/620282 |
Filed: |
July 14, 2003 |
Current U.S.
Class: |
24/570 |
Current CPC
Class: |
H01L 21/67333 20130101;
Y10T 24/44983 20150115 |
Class at
Publication: |
024/570 |
International
Class: |
A44B 021/00 |
Claims
1. An apparatus for clamping together in a stack at least one tray
adapted to hold a plurality of integrated circuits in pockets
disposed therein and a cover, the apparatus comprising: a base
forming a bottom of a channel, the channel allowing for the
insertion and removal of the stack; first and second restraining
segments attached to the base that together with the base form a
channel structure, wherein the channel structure restricts
substantial movement of the stack both transverse to a length of
the channel and perpendicular to a plane of the base; and at least
two pressure members attached to the channel structure for
providing pressure on a perimeter of the stack to clamp the stack
together between each of the pressure members and a portion of the
channel structure, thereby preventing movement of the tray
independent of the cover and ensuring that the integrated circuits
maintain disposed within the pockets of the tray.
2. An apparatus as recited in claim 1 wherein only the at least two
pressure members apply pressure to the stack, and include: a first
resilient member extending from the base on one end of the channel;
and a second resilient member extending from the base on a second
end of the channel that is opposite the one end of the channel.
3. An apparatus as recited in claim 1 wherein the first and second
restraining segments each include: a wall extending upward from the
base, each wall disposed on respective opposing sides of the
channel; and a protrusion attached to the wall above the base and
extending inwards towards the channel so as to extend over the
perimeter of the stack when the stack is inserted in the
channel.
4. An apparatus as recited in claim 3 wherein the portion of the
channel structure is the protrusions: and wherein the at least two
pressure members include: a first resilient member extending from
the base on one end of the channel; and a second resilient member
extending from the base on a second end of the channel that is
opposite the one end of the channel.
5. An apparatus as recited in claim 3 wherein the portion of the
channel structure is the protrusions: and wherein the two pressure
members include: a first pressure member extending from the base
and positioned adjacent the one side of the channel; and a second
pressure member extending from the base and positioned adjacent the
opposing side of the channel.
6. An apparatus as recited in claim 3 wherein the portion of the
channel structure is the base; and wherein the two pressure members
include: a first pressure member extending from one of the
protrusions and positioned adjacent the one side of the channel;
and a second pressure member extending from the other of the
protrusions and positioned adjacent the opposing side of the
channel.
7. An apparatus as recited in claim 1 wherein only the at least two
pressure members apply pressure to the stack, and include: a first
pressure member extending from one of the base and one of the
protrusions and positioned adjacent the one side of the channel;
and a second pressure member extending from one of the base and the
other of the protrusions and positioned adjacent the opposing side
of the channel.
8. The apparatus according to claim 1 wherein the apparatus is
injection molded in one piece using an injection molding
material.
9. The apparatus according to claim 8 wherein the at least two
pressure members each are disposed in a first plane different than
a second plane formed by a surface of the channel structure to
which each of the at least two pressure members are attached.
10. An apparatus as recited in claim 9 wherein the first and second
restraining segments each include: a wall extending upward from the
base, each wall disposed on respective opposing sides of the
channel; and a protrusion attached to the wall above the base and
extending inwards towards the channel so as to extend over the
perimeter of the stack when the stack is inserted in the
channel.
11. An apparatus as recited in claim 10 wherein the portion of the
channel structure is the protrusions: and wherein the at least two
pressure members includes: a first resilient member extending from
the base on one end of the channel; and a second resilient member
extending from the base on a second end of the channel that is
opposite the one end of the channel.
12. An apparatus as recited in claim 10 wherein the portion of the
channel structure is the protrusions: and wherein the two pressure
members include: a first pressure member extending from the base
and positioned adjacent the one side of the channel; and a second
pressure member extending from the base and positioned adjacent the
opposing side of the channel.
13. An apparatus as recited in claim 10 wherein the portion of the
channel structure is the base; and wherein the two pressure members
include: a first pressure member extending from one of the
protrusions and positioned adjacent the one side of the channel;
and a second pressure member extending from the other of the
protrusions and positioned adjacent the opposing side of the
channel.
14. An apparatus as recited in claim 8 wherein only the at least
two pressure members apply pressure to the stack,
15. An apparatus as recited in claim 1 wherein only the at least
two pressure members apply pressure to the stack.
16. An apparatus for clamping together in a stack at least one tray
and a cover, the apparatus comprising: horizontal restraining means
for restraining the stack laterally in one direction; vertical
restraining means for restraining the stack in a vertical
direction; and pressure means for application of a force to urge
the stack into contact with a portion of the vertical restraining
means, wherein the pressure means is configured for applying the
force only to a perimeter of the stack.
17. An apparatus as recited in claim 16 wherein: the horizontal
restraining means includes first and second side walls spaced apart
to form a channel; and the vertical restraining means includes a
base and first and second protrusions each extending inwards from
the first and second walls.
18. An apparatus as recited in claim 17 wherein the pressure means
is attached to the base.
19. An apparatus as recited in claim 18 wherein the pressure means
includes a first resilient member disposed at a first end of the
channel and a second resilient member disposed at a second end of
the channel.
20. An apparatus as recited in claim 18 wherein the pressure means
includes a first resilient member disposed on the base opposite the
first protrusion and a second resilient member disposed on the base
opposite the second protrusion.
21. An apparatus as recited in claim 17 wherein the pressure means
is attached to the first and second protrusions.
22. An apparatus as recited in claim 21 wherein the pressure means
includes a first resilient member attached to the first protrusion
and a second resilient member attached to the second
protrusion.
23. A method of holding a plurality of integrated circuits within
pockets of a tray, and wherein the tray has a cover disposed
thereover so that the tray and the cover form a stack, the method
comprising the steps of: inserting the plurality of integrated
circuits within the pockets of the tray; covering the tray with the
cover to form the stack; and clamping the stack by applying a force
only at a perimeter of the stack using a one-piece re-usable
assembly, the step of clamping applying the force at opposite ends
of the stack to maintain stability of the stack and ensuring that
the integrated circuits maintain disposed within the pockets of the
tray.
24. An apparatus as recited in claim 1 wherein said pressure is
additionally applied to a non-perimeter area.
25. An apparatus as recited in claim 16 wherein a force is
additionally applied to a non-perimeter area.
26. A method as recited in claim 23 wherein pressure is
additionally applied to a non-perimeter area.
Description
[0001] This application is related to U.S. patent application
entitled "Open Frame Tray Clip" [Attorney Docket No. 67810-0304489]
filed the same day as this application, and which is expressly
incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to apparatus for securing
trays that are used in storing or transporting components such as
semiconductors, and more particularly to a clip for securing a tray
and cover or stack of trays and a cover that places stack
compression forces on tray perimeter rails in order to minimize
tray distortion caused by clip forces.
[0004] 2. Description of the Prior Art
[0005] Small components such as semiconductors are often stored or
shipped in molded plastic trays such as tray 10 shown in FIG. 1.
With the components (not shown) in pockets 12, a cover such as
cover 14 is placed over the tray 10 for captivating the components
in the pockets 12. It is then often necessary to apply a device to
secure the top 14 to the tray 10. For example, FIG. 2 illustrates a
two part clip apparatus 16 used to clamp a tray and cover together,
or a stack of trays and a cover together. The height of leg 18 is
designed to accommodate the height of the stack. FIG. 3 illustrates
the use of a two part clip apparatus 20 for securing a cover 22 to
a tray 24. FIG. 4 illustrates another type of tray clip 26.
[0006] In order for the stack of trays to be secure, the clip
provides a compressive force to the stack. Prior art designs apply
force to a central area of the bottom of the stack, which
eventually causes permanent warp/distortion of the trays. Prongs
such as 28 (FIG. 2) are used at the stack top, with the opposing
force in the central area of the bottom of the stack. In FIG. 2,
each of the extensions 30 slide under the corresponding mating part
and provide an interference, causing the base 32 to bend in a
manner that results in the clip applying a spring force when the
clips are installed on a stack.
[0007] FIG. 4 shows another clip apparatus 26 with two leaf springs
34 for application of force to a stack inserted in the clip 26. The
designs of FIGS. 2-4 apply a leverage to the tray, operating
between each of the top prong contact points and the corresponding
area of contact on the central area of the bottom of the stack..
The leverage applied to the tray by the spring force is
proportional to the distances roughly indicated for example by
dimensions D.sub.1 and D.sub.2 resulting in application of a
bending force to the trays. This force causes damage due to the
application of the force in the thin and-weak central area. As the
trays warp over time, gaps are produced between trays in a stack.
In some cases, the components stored in a tray can fall through the
gaps, or be pinched in a gap, causing damage to the component. In
addition, when a stack of trays is removed from a clip, and a tray
is presented to an automated pick and place machine, the warped,
distorted tray can cause pick-up errors. The problem of warped
trays is augmented in situations when trays are recycled i.e.
re-used after having been used in a stack and become warped. For
example, if a used warped tray is placed in a stack with a new tray
or new cover, significant gaps are possible, causing tray
components to fall out.
SUMMARY
[0008] It is an advantage of this invention in that it provides an
improved clip for securing a stack of trays that minimizes warp due
to tray clip forces.
[0009] It is a further advantage of this invention in that it
provides a clip for securing a stack of trays that confines the
retaining forces to the tray edges and therefore minimizes leverage
to the stack and reduces tray warpage.
[0010] In one embodiment of the present invention, a clip is
provided for holding a stack of at least one tray and tray cover.
The clip has a channel structure providing a channel, and having
first and second restraining segments positioned on opposing sides
of the channel. The segments are attached to a channel base. The
restraining segments and base restrict lateral and vertical
movement of a stack of trays placed in the channel. At least one
pressure member is provided that applies a vertically directed
pressure component on a perimeter portion of the stack, forcing the
stack into contact, with an opposing portion of the channel
structure. Stack compressive forces applied by the clip are
substantially limited to tray and cover perimeter rail portions. In
a particular embodiment, the clip has a channel base with left and
right side retaining walls attached for restricting movement of a
stack in left and right directions. Left and right side protrusions
above the base extend inward towards the center of the channel from
the left and right side walls respectively for captivating the
stack in an upward direction. The pressure members include
resilient protrusions extending upward from the base on input and
output ends of the channel that are configured for applying an
upward spring force on corresponding bottom edge/perimeter areas of
the stack.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a prior art tray and cover;
[0012] FIG. 2 illustrates a prior art two piece clip;
[0013] FIG. 3 illustrates a clip of the type shown in FIG. 2
holding a stack;
[0014] FIG. 4 shows a prior art clip having two centrally located
springs for applying stack pressure;
[0015] FIG. 5 is a perspective view of a clip according to the
present invention, and a representative tray with cover in a
position for installation in the clip;
[0016] FIG. 6 is a bottom perspective view of the clip of FIG. 5
with a stack installed;
[0017] FIG. 7 is a top perspective view of the assembly of FIG.
6;
[0018] FIG. 8 illustrates a tray using springs to apply force to
the left and right edge areas;
[0019] FIG. 9 shows an alternate clip design for applying force to
right and left tray perimeter areas;
[0020] FIG. 10 shows another alternate clip design using spring
protrusions to apply force to left and right side tray perimeter
areas, and shows a tray and cover in position for insertion in the
clip, and shows retainer protrusions from a tray base for resisting
longitudinal stack movement;
[0021] FIG. 11 shows a stack installed in the clip of FIG. 10;
and
[0022] FIG. 12 is a cross sectional view from FIG. 11, showing the
position of the retainers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] While the present invention will be described herein with
reference to particular embodiments thereof, a latitude of
modifications, various changes and substitutions are intended, 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 described with respect to the preferred embodiments
set forth herein.
[0024] Referring now to FIG. 5 of the drawing, a particular
embodiment of the present invention is shown in the form of a clip
36 for holding a stack, such as stack 38 including a tray 40 and
cover 42. The clip 36 forms a channel structure providing a channel
44. The structure includes a clip base 46, and has first and second
retaining segments 48 and 50 that can be of various forms,
illustrated in FIG. 5 as vertically oriented walls providing left
and right captivation of a stack. The retaining segments and base
restrict lateral and vertical movement of a stack of trays placed
in the channel. Vertical captivation of a stack in the particular
embodiment of FIG. 5 is provided in the upward direction by right
side and left side protrusions 52 and 54, positioned above a
channel base 46, and inwardly directed towards a central area of
the channel 44 from left and right side restraining apparatus 48
and 50 respectively. The protrusions 52 and 54 are positioned above
the base 46 so as to lie above the right and left side edges/rails
56 and 58 of a stack 38 positioned in the channel 44 of the clip
36.
[0025] According to the present invention, a pressure member is
provided that applies a vertically directed pressure component on a
perimeter portion of the stack, forcing the stack into contact with
a opposing portion of the channel structure. The pressure member in
the particular embodiment of FIG. 5 is shown as first and second
resilient members 60 and 62 extending from the base 46 at first and
second opposing ends 64 and 66 of the channel 44. The members 60
and 62 as shown are resilient protrusions from the base 46,
extending in an upward direction, having contact areas 68 and 70
positioned so as to contact and apply an upward force on
perimeter/edge/rail portions 72 and 74 (FIG. 6) of a bottom tray of
a stack inserted in the clip 36. The edge/perimeter/rail portions
72 and 74 are the portions as shown surrounding the bottom cavity
75 of the tray 40. FIG. 6 is a bottom view of the clip 36 of FIG. 5
with the stack 38 inserted in the channel 44. FIG. 6 clearly shows
the resilient first and second members 60 and 62 deflected by-the
edge portions 72 and 74 of the tray 40, the members applying a
force on the edge portions 72 and 74, forcing the stack 38 into
contact with the protrusions 52 and 54, and thereby captivating the
stack in the clip 36.
[0026] FIG. 7 is a top perspective view of the assembly of FIG. 6,
showing the protrusions 52 and 54 extending over the edge portions
56 and 58 of the stack 38.
[0027] The above-described embodiment is given by way of example.
This embodiment of the present invention substantially restricts
the application of force by a clip to perimeter areas near the
edges of the trays, applying the force to the side rail portions of
72 and 74. Various alternate embodiments will be apparent to those
skilled in the art upon reading the present disclosure, and these
alternate embodiments are included in the spirit of the present
invention. For example, instead of the single leaf type members 60,
62 as shown in FIGS. 5-7, other configurations could be used,
including a plurality of members on either or both of the input
and/or output of the channel 44. For example, FIG. 8 shows a clip
76 with springs 78 positioned under the protrusions 80 and 82 for
applying a spring force substantially at the perimeter side rail
areas of a tray according to the spirit of the present invention. A
simple elongated spring of various designs could alternatively be
used on each side instead of the two springs 78 per side. FIG. 9
shows a further alternate embodiment of a clip 84 wherein resilient
members 86 are shown having an integral, molded design similar to
the members 60 and 62 of FIGS. 5-7, but smaller and placed near the
right and left tray edges, instead of making contact under the
front and back tray edge areas as in FIGS. 5-7. The springs 78 as
shown, are positioned/configured for pressuring a stack of trays
against the under side of the protrusions 80 and 82. As a alternate
embodiment, springs 83 similar to springs 78 can be alternatively
positioned and attached to the protrusions 80 and 82 for pressuring
perimeter portions of a stack of trays, forcing the stack against
the base 85. As a still further embodiment of the present
invention, an apparatus is provided in a plurality of parts,
wherein each part provides a clamping action on a perimeter portion
of a stack. For example, referring again to FIG. 8, if the portion
designated by dashed lines 77 were removed, the result would be two
parts 79 and 81 which could be used to restrain a stack in a
similar way as described above in describing the clip 76.
[0028] A further alternate embodiment 88 of a clip according to the
present invention is illustrated in FIG. 10. Pressure members in
the form of resilient leaf members 90 and 92 are shown positioned
so as to bring leaf surfaces 94 and 96 into contact with edge
portions of a tray 98 when inserted into the clip channel 100. The
surfaces 94 and 96 are most effectively positioned below the
protrusions 102 and 104. As a further alternate embodiment, the
clip 88 can additionally include flexible retainers 106 and 108
that extend upward-from clip base 110 for assisting in securing a
stack in the clip. FIG. 11 shows a stack 114 including the tray 98
and cover 112 installed in the clip 88.
[0029] FIG. 12 is a cross section A-A from FIG. 11 showing the
positions of the retainers 106 and 108 that protrude into the tray
bottom cavity 116 to provide added resistances to movement of the
stack 114 for retaining the stack 114 in the clip 88. FIG. 12 shows
gaps 109 and 111 between the ends of the retainers 106 and 108. The
present invention includes any size gap, including no gap i.e. an
interference fit that would more strictly prevent tray movement.
The function of retainers 106 and 108 can be accomplished with
other structures that will be apparent to those skilled in the art
upon reading the present disclosure. In addition to other retaining
structures built into the clip, a cut-out such as shown by dotted
lines 115 in the tray 98 of FIG. 10 can be included, into which the
leaf 92 would reside upon insertion of the tray 78 in the clip 88.
The tapered edges 117 would allow the tray 98 to be forced out of
the clip, while providing sufficient resistance to retain the stack
under normal forces of handling and other anticipated forces,
etc.
[0030] Although the designs of FIGS. 5-7 and 9-12 are described as
a single molded piece, the present invention applies also to clips
constructed forming a plurality of separate parts. Also, various
types of materials can be used to fabricate the clip. For example,
the present invention applies to a clip apparatus with pressure
members that are separately manufactured parts. The clip body can
also be constructed with two or more parts, such as a separate clip
for each of two ends of a stack that restrict the forces to tray
perimeter/edge areas.
[0031] The preferred embodiments as described above, and variations
that will be apparent to those skilled in the art, limit the
application of pressure to the trays to the perimeter area. As a
further alternative embodiment, pressure can additionally be
applied to non-perimeter areas.
[0032] 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.
* * * * *