U.S. patent number 3,683,821 [Application Number 05/075,120] was granted by the patent office on 1972-08-15 for pallet.
Invention is credited to Robert T. Mangold.
United States Patent |
3,683,821 |
Mangold |
August 15, 1972 |
PALLET
Abstract
Stacked empty pallets having registering sockets in adjoining
surfaces are interlocked by latch members carried by yieldable arms
extending from the mid sections of the sockets and yieldably
projecting from the socket of one pallet into the corresponding
socket of an adjoining pallet.
Inventors: |
Mangold; Robert T. (Erie,
PA) |
Family
ID: |
22123682 |
Appl.
No.: |
05/075,120 |
Filed: |
September 24, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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38778 |
May 19, 1970 |
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Current U.S.
Class: |
108/53.1;
108/901 |
Current CPC
Class: |
B65D
19/0012 (20130101); B65D 2519/0096 (20130101); B65D
2519/00268 (20130101); B65D 2519/00557 (20130101); B65D
2519/00034 (20130101); B65D 2519/00069 (20130101); Y10S
108/901 (20130101); B65D 2519/00288 (20130101); B65D
2519/00318 (20130101) |
Current International
Class: |
B65D
19/00 (20060101); B65d 019/38 (); B65d
021/00 () |
Field of
Search: |
;108/51-58 ;220/84 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McCall; James T.
Assistant Examiner: Finch; Glenn O.
Parent Case Text
This invention is a continuation in part of application Ser. No.
38,778 filed May 19, 1970.
Claims
What is claimed is:
1. In a molded plastic pallet having vertically spaced load
carrying surfaces and means providing sockets extending in the
thickness direction between said surfaces with open ends presented
to said surfaces and registering with the open ends of sockets of
adjoining pallets in a stack of pallets of like construction, said
sockets having plastic walls extending in the thickness direction
inward from said surfaces, latch means having a stationary part
comprising a cross wall molded integral with one of said walls
inward of said surfaces and connected by resilient means to a
movable part outward of one of said surfaces in position to enter
the open end of a socket of an adjoining pallet of like
construction, said resilient means yielding to permit retration of
the movable part of the latch means into the associated socket.
2. The pallet of claim 1 in which the movable part of the latch has
a post guided in the stationary part.
3. The pallet of claim 1 in which the resilient means is a coil
spring surrounding the post and biasing the movable part outward of
the socket.
Description
This invention is an improvement on U.S. Pat. No. 3,363,590,
simplifying the latch construction for interlocking empty pallets
so as to hold them in stacked relation.
In the drawing,
FIG. 1 is a perspective of a stack of empty pallets,
FIG. 2 is a fragmentary bottom plan view of one of the pallets,
FIG. 3 is a section on line 3--3 of FIG. 2,
FIG. 4 is a view similar to FIG. 3 of a modification using a strip
spring to urge the latch member upward,
FIG. 5 is a fragmentary view showing the manner in which the strip
spring is secured to the socket,
FIG. 6 is a fragmentary end view of the groove in which the strip
spring is secured,
FIG. 7 is a sectional view on line 7--7 of FIG. 8 showing another
modification,
FIG. 8 is a plan view of the outer end of the latch, and
FIG. 9 is a plan view of the inner end of the latch.
In FIG. 1 there is shown a stack of a plurality of pallets 1 of
generally rectangular shape having peripheral side and end walls 2
each provided with a pair of fork entry openings 4 to provide the
usual four-way entry. Each pallet has upper and lower load carrying
surfaces 6 and 7. The particular pallet shown is constructed in
accordance with U.S. Pat. No. 3,307,504, incorporated by reference.
As described in greater detail in that patent, the load carrying
surfaces 6 and 7 of each pallet is associated with the lattice of
intersecting ribs presented edgewise to the surfaces and providing
a rigid construction which is adapted to molding from impact
resistant plastic such as polyethylene. This is merely one of the
pallets to which the present invention is applicable.
In order to hold the empty pallets in stacked relation as shown in
FIG. 1, at several (e.g. four) points around the periphery of the
pallet there are provided sockets 8 which extend between the
surfaces 6, 7. As shown in FIGS. 1 and 2, the sockets are spaced
inward from the outer walls 2 of the pallet. Each socket comprises
walls 9, 10, 11 and 12, each extending in the thickness direction
between the surfaces 6, 7 and each integral with the adjoining
sections of the pallet.
At the center of one end of each of the sockets 8 is a latch member
13 supported by one of the walls of the socket, for example the
wall 11. The latch member has rectangular sides 14 and ends 15 at
the center of which is a rounded projection 16. When the pallets
are stacked one on top of the other, the latches 13 enter the
sockets 8 in the adjoining pallet. The rectangular sides 14, 15
provide abrupt shoulders for holding the pallets in alignment. The
rounded projection 16 acts as a cam surface which allows the
pallets to slide into position as they are stacked. Once the
latches have entered the sockets 8, the stack of pallets is
interlocked by the latches so that they will remain in stacked
relation.
The manner of making the latch members 13 is shown in FIG. 3. As
molded, the latch member 13 is integral with the lower ends of arms
17, 18 of width substantially equal to the length of the latch.
When viewed in section, the arms 17, 18 and the associated latch 13
form a U with the latch at the base of the U and with the arms
offset laterally from the walls of the socket. The arm 18 is joined
to the socket wall 11 by a curved section 20. There is a similar
curved section 19 at the upper end of the arm 17 which has a cut or
interruption 19a so that after removal from the mold the latch
member 13 and the arms 17, 18 assume the position generally
indicated by dotted lines 13a, 17a and 18a. The arm 18 with the
associated section 20 forms a yieldable support for the latch
member 13 which permits the latch member 13 to be moved laterally
and in and out of the socket so as to prevent damage to the latch
members while the pallets are being used. For example, when the
pallet is supported by its lower surface 7, the latch members 13
are free to retract within the socket. While the pallets are being
stacked, the latch members 13 are free to move either laterally or
inwardly. When the latch members 13 come into alignment with a
socket 8 in an adjoining pallet, the latch members spring into
engagement with the adjoining socket and provide a mechanical
interlock which holds the pallets in stacked relation but which
yields to permit removal from the stack without injury to the latch
members or the associated parts of the pallet.
The arms 17, 18 and the section 20 are substantially wholly within
the sockets 8 and are well protected. The latch construction is
adapted to molded plastic pallets. The integral construction
provides reliability at minimal cost.
In order to increase the speed of operation of the latch member 13,
a supplemental strip spring 21 may be used. One end of the spring
has an angular section 22 seated on the inner surface 23 of the
latch member. The other end of the spring has a head 23 received in
a T-slot 24 molded integral with the wall 1. The head is provided
with inclined barbs 25 which dig into the bottom walls 26 of the
T-slot and resist movement out of the slot. The spring may be
easily installed by pushing the head 23 downward into the T-slot
until the lower end 22 seats on the surface 23 of the latch member
13. Once pushed into place, the barbs 25 resist outward movement
and hold the spring in assembled relation. The spring supplements
the inherent resilience of the arm 18 of the latch member and in
addition overcomes any tendency of the arm 18 to take a set if held
in its retracted position for a long period of time.
The T-slot 24 which may be molded integral with the pallet provides
a simple construction for fixing one end of the supplemental spring
to the pallet with minimal material and assembly cost.
In the modification of FIGS. 7-9, where corresponding parts of the
pallet are indicated by the same reference numerals, the stationary
part 27 of the latch comprises a cross wall or partition integral
with the socket walls 9, 10, 11 and 12 and having at its center an
integral tubular guide 28, preferably of square or other non
circular cross section. The movable part 29 of the latch is
slidable in the socket 8 and has outwardly projecting ribs 30
slidably engaging the socket walls 9, 10, 11 and 12. On its under
side the latch member has a hollow post 31 slidable in the guide
member 28. At the inner end of the post 31 are a plurality of
resilient fingers 32 having outwardly projecting hook or locking
projections 33 cooperating with the inner end of the guide 28 to
limit the outward movement of the latch member. Spring means such
as a coil spring 34 arranged between the latch member 29 and a
suitable part of the stationary member 27 urges the latch member
outward so that in the extended position shown in FIG. 7 the hook
members 33 stop against the inner end of the guide 28. When the
latch member 29 projects downward, as shown, gravity would provide
equivalent spring action. The coil spring 34 permits operation with
the latch member 29 extending upward. The latch member 29 and the
spring 34 are separately manufactured parts. In the assembly, the
spring 34 is assembled on the post 31 and the assembly is pushed
into the guide 28 until the hook members or projections 33 move
past the inner end of the guide 28. Upon reaching this position,
the hook members 33 spring outwardly and hold the latch member 29
in assembled relation to the stationary latch part 27.
The latch member 29 has abrupt surfaces 35 which when received in
the open end of one of the sockets 8 of an adjacent pallet
cooperate with the walls 9, 10, 11 and 12 of that socket and hold
the pallets in aligned relation. Because the locking surfaces 35
resist relative movement in all directions, only two latches per
pallet are needed to provide positive alignment in the stack. The
latch members 29 also have four inclined surfaces 36 which act as
cam surfaces to assist in leading the latch members into the
sockets so as to assist in bringing a pallet being stacked into
alignment with the other pallets in the stack. The cam surfaces 36
also assist in camming the latch members inward.
The reference to upper and lower load carrying surfaces of the
pallet refers to the position of the surfaces in the particular
stack. The stack could be inverted without changing the operation.
The terms upper and lower are, accordingly, interchangeable and not
words of limitation.
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