Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to tailgate lift platform
mechanisms for trucks and the like.
In particular, this invention relates to an improved
retention Eence for a tailgate lift platform.
A retention fence for a tailgate lift pla-tEorm is
described in United States Paten-t No. ~,198,18~ dated April 15, 1980
issued to William V. Perkins. In this mechanism, the retaining
fence is in the form of a pair of rigid arms which are pivotally
connected to the slides on which the platform is pivoted at a
substantial distance above the platform. The arms pivot between an
upright position and a horizontal posltion in response to movement
of -the platform between its upright position and its horizontal
position. When in the upright position, the arms project above the
outer end of the platform and in many applications these arms may
project above the body of the truck to which the platform is
attached. There are many installations where restricted head room
is available for trucks backing in to loading docks and the side
~ences of this prior pa-tent can extend to a height above the body of
the truck so as to form an obstruction preventing backing up to a
loading dock.
Parallelogram linkage mechanisms are notoriously difficult
to maintain in good working order in environments where they are
subjected to impact loading and consequently, considerable
difficulty would be experienced in attempting to maintain the
parallelogram linkage mechanism used for deploying -the platform and
retaining arms of Perkins.
It is an object of the present inven-tion to pxovide a
simple and inexpensive retention ~ence mechanism which can be s-tored
in a compact conEi~uration in close proximity to the ~latforM when
it is in its storage position.
:Lt is a further object oE the present inventiotl to provide
a silnple ancl i.nexpensis7e retention Eence in which the deploymentt
mecharlism includes flexible side -Eences and flexible ties connected
to the distal end rigid arms which are pivotally connected to the
pla-tform adjacent the inner end of the platform.
Accordin~ to one aspect of the present invention, there is
provided in a tailgate loacler of a truclc or the like, having a load
elevator mechanism which cornprises a loading platfor~ which has an
inner end and an outer end and a pair of oppositely disposed side
edges and ~7herein the platEorm is pivotally mounted at its inner end
on a pair of slide rnembers :Eor mo~ement abou-t a Eirst axis between
an uE)righ-t storage position and a generally horizontal deployed
posit:ion, said slide members being movable relative to the truck to
raise and lower the plat:Eorm as required in use, the improvernen-t of
a load retention Eence comprises; a pair oE e:lonqated arms each
having a proximal end and a distal end, the proximal end ot each arm
being pivotally mounted on said plat:Eorm at a side edge -thereof at a
point adjacent said inner end of said platform, said arms being
movable relative to said platform bet~een a storage position in
which they are upright and extend substan-tially parallel to the
platform when the platform is in its storage posi-tion and a
deployed position in which they ex-tend upwardly and rearwardly
from the inner end of the platform when the platform is in its
deployed position, said arms having a sufEicient length to locate
the d:istal ends thereoE, a substantial distance above the
platform and overlying the outer portion o:E the platform when in
said cleployed position, flexible side fence means connecting the
distal end of each arm to an adjacent slide member so as to
prevent rotation of each arm relative to the platform beyond that
required for movement between said storage position and said
deployed position of said arms, said side fence means being
connected to said slide members at a height above the pivotal
connecl:ion of the platform to the slide members so as to extend
substantially hori20ntally when the a.rms are deployed to form a
load restraining side fence at each side of the platform,
flexible tie means connecting the distal end of each arm and -the
outer end of said platform, said flexible tie means having a
length so as to be taught when said platform is in its deployed
position and said arms are in their deployed position, said
flexible tie means serving to automatically deploy said arms in
response to movement of said platform between its storage
position and its deployed position, outer fence means detachably
mountable at the distal ends oF said arms to extend transverselY
therebetween when said a~l~s are deployed so as to Eorm a load
retaining fence at a subst.antial distance above the outer end of the
plat~orrn ~hen the platform is in its deployed positiorl, said outer
l.-ence means beincl de~achable so as to be removable to avoid forming
an obstruction when said arms are in their storaqe position~
PREFERRED_~MBODIMENT
The invention will be more clearly understood after
reEerence to the following detailed specification read in
conjunction with the drawings wherein,
Figure 1 is a pictorial side view of a li~t tailgate
showing the load xetention fence in its deployed position.
E`i~ure 2 is a partial view of the tailgate of Fi~ure 1
showing the platforrn and load retention Eence in their storage
position.
Figure 3 is an enlarged detailed view showinq the outer
fence mounted on the distal ends of the elongated arms.
With reEerence to Fi~ure 1 of the drawings the reference
numeral 10 refers generally to a tailgate loader constructed in
accordance with an embodiment of the present invention. The
tailgate loader is of a conventional type which includes an elevated
ride mechanism which is not shown which serves to raise and lower a
pair of slide members 12 which are slidably mounted in guide rail.s
14 which are mounted at the loadi7lcJ end of a truck generally
identified by the reference numeral 20. A platform 16 has its inner
end pivotally rnoullted on luqs 18 of the slide members 12 means of
pivot pin.s 22. rrhe platform 16 is movable between the deployed
generally horizon-tal position shown in E'igure 1 or -the drawings and
the upright storage position shown in E`igure 2 of the drawirlqs. In
mo~ing between the deployed position and the upriqht position, the
pla-tEorm pivots about the pivot ends 22 in the direction of the
arrow B. A pair oE brackets 2~ project laterally ~rom the opposite
side edges o~ the platform. As shown in Figur~ 2 oE the drawings,
the braclcet.s 24 serve as latches which ma~ be releaseably retained
by latch ~lates 26 t~ retain the platform 16 in its upright storage
position. The latch 24 may be positioned in the latch plate 26 or
released from the latch plate 26 by causing the slide mernbers 12 to
be lowered or raised in the direction of the arrows ~ oE Figure 1
when in the upright configuration.
The load re-tention fence comprises a pair o~ rigid arms
30, a pair of ~lexible side fence chains 32, a pair of ~lexible tie
chairls 34 and a detachable outer fence rail 36.
The elongated arms 30 each have a pro~imal end 3~ and a
distal end ~0. I'he proximal end 38 or each arm is pivotally
connected by means of a pivot pin 42 to a side edge of the plat~orm
16 closely adjacent the inner end of the platform 16. A lug 4~
projects laterally from the arms 30 and serves -to bear against the
back edge of the slide mernbers 12 as shown in Figure 2 of the
drawings when the arms 30 are in the upriqht storage position so
that the arms 30 are retained in the upright position between the
engagement with the slide member 12 and the latch 24.
A bracke-t 46 (Fig.l and Fig.3) is located at and projects
laterally from the distal end of each arm 30. The bracket 46 has
mounting passages 48 and 50 opening therethrough.
The arms 30 are movable relative to the platform between
the storage position shown in Figure 2 of the drawings in which they
are upright and extend substantially parallel to the platform and
the deployed position in which they extend upwardly and rearwardly
fro~l the inner end of the platEorm. The arms have a suEficient
length to locate the distal ends thereof a substan-tial distance
above the platform and overlying an outer portion of the platform
when in the deployed position. Preferably, the arms will have a
sufficient length to ensure that the distal end 40 of each arm is
positioned at a height of about 3 to 4 feet above the platform in
the deployed position so as to be suitable for supporting unstable
loads such as pressurized gas cylinders.
The flexible side fence chains 32 have one end connected
to a lug 52 located at the upper end of the slide 12 and their other
end located in the mounting passages 48 of the lugs 46 of the arms
30. The chains 32 are in the form of strong metal link chains are
proportioned to limit rotation of the arms 30 relative to the
platform 16 to that re~uired to deploy the arms 30 and to pre~ent
further rotation beyond the deployed position. The chains 32 are
connected to the slide 12 at a height above the platform so as to
extend substantially horizontally when the arms are deployed as
shown in Figure l of the drawings. The weight of the platform is
born by the chains 32 with the result that the chains are retained
in a taut condition and serve as load restraining side fences.
While the chains 32 are retained taut they are su:Eficiently
flexible that they will yield when subjected to a heavy loacl and
will not become inoperative by reason of deElection under the
influence o:E a load.
~ llhe flexible tie melnbers 34 are in the :Eorm of. metal link
chains havinq one end conllected to the d.istal end of each arm by
connection with the mounting passage 50 of the luq 46. The other
end of each fl.exible tie 3~1 is connected to a lug 54 which projects
~rom the inner face oE the latch 24. Thus it will be seen that the
f].e~ible tie chain 3~ serves to connect the distal ends of the arms
30 to the platform 16 adjacent the outer edae thereof. The lugs 46
and 54 are arranged such that when the arms 30 are in the deployed
position the :flexible tie chains 34 will extend substantially
vertically. The chains 34 have a length so as to be taut when the
platEorm i5 deployed in a generally hori~ontal plane and the arms
a.re in the their depl.oye~ position. The chains 34 and 36 serve to
automatically deploy the ~rms 30 in their deployecl position when the
platorm moves from its storage position to its depl.oyed posi-tion.
The outer fence member 3G is in the form of a tubular
member 60 which has a pair oE elbows 62 projecting one from each end
thereof. The elbows 62 are proportioned to fit within sleeves 64
which are secured as by welding to the inner faces 66 of the distal
ends of the arms 30. A lockinq pin 68 is removably mounted in a
passage 70 formed at the end of one of the elbows 62 so as to
provide a suEficient free vertical length of elbow 62 to permit the
other elbow 62 to be raised and lowered into and Ollt oE engagement
wi-th the socket 72 formed in the sleeve 64. This permi.ts the rail
. ~ .
36 to be raised to release one oE the elbows 62 from its socket 72
50 that the fence can be pivoted a~out its other end in the
direction o~E the arrows C shown in Figure l of the drawings. This
permits openinq and closinq oE the retaininy fence without -the need
to cornpletely remove the retaining Eence.
In use, the pl.atform 16, arms 30 and chains 32 and 34 are
sto:red in the con-fi~uration shown in Eigure 2 of the drawings with
the latch 24 positioned in the latch plate holder 26. If re~uired,
the outer fence rail 36 may be complete1y removed.
In order -to deploy tne plat~orm and the load retaining
fence, it is merely necessary to raise the platform Erom the
position shown in Figure 2 by raising the slides 12. After the
latch 24 has been raised out o:E engagement wi-th the latch plate 26,
the platEorm 16 may be manually engaged to cause it to pivot about
its pivotal connection with -the slides 12 to move toward the
horizontal deployed position shown in Figure 1. Generally the arms
30 will move outwarclly wi-th the platform 16 until the chains 32 are
drawn taut. Thereaf-ter, the platform 16 will pivot relative to the
arms 30 until the chains 34 are taut. When the chains 32 and 34 are
taut, the arms 30 and pla-tforms 16 are automatically retained in
their deployed position shown in Fi~ure 1. The platform may be
raised and lowered in the direction of the arrow A when in the
deployed position as is conven-tional practice. When a load is to be
unloaded from the body of the truck with the platform in the raised
position, the load may be positioned so as to bear against the side
~ence chains 32 and/or the outer fence 36. Additional tie members
may be provided (not ~hown) .tor tying the load me~bers a~ainst the
side fence chains 32 or the outer fence 36 as required in use.
After the platform is lowered to the position shown in ~`igure 1, the
outer Eence 3G ma~ be opened as previouslv descri~ed to permit -the
removal o~ the load from the platforrn. It will be apparent that in
some ci~curnstances i~ may be desirable to cornpletely remove the
outer ~ence 36 and this can be done with ea~se by removirlq the
loc~.ing pin 36.
In o.rde.r to return the platform 16 -to the storage
position, it is merely necessary to pivot the platEorm about its
pivot pins 22 in the direction oE the arrow ~ (Fig.~). Initially,
this action will cause the chains 34 to collapse and thereafter, the
bracket.s 24 will engage the distal ends of the arms 30 so that
continued movement will cause both the platform and -the arrns 30
to move to thei.r up.right posi-tion. By raising the slides 12 to a
position in which the latches 24 are disposed above the notches
which are Eormed in the latch plates 26, it is possible to position
the latch 24 in ali~nment with the notches of the latch plates 26
and therea.Eter to lower the latches 2~ into the latch plates 26~
Various modifications of the present invention will be
apparent to those skilled in the art. E'or example, it will be
apparent that the outer fence 36 may be in the form of a Elexible
chain ~Jhich is proportioned so as to be substantially taut when
extended between the distal ends of the arms 30 in use. Ln
addition, it will be apparent that because the arms 30 are pivotally
connected to the platform, the arms can be proportioned so as to
extend only a short distance above the outer edge oE the platform
r~hen i~ is in the storage position. This is of importance in
application where the vehicle is -to be loaded and unloaded at a
loadinq dock which is of a height substantially equal to the height
of the bed of the truck. It will be understood that the platforrn
illus~rated in Figure l ot the drawings can be moved to an upright
storaqe ~osition when the slides 12 are in the lowered position
shown in F`igure l in wnich case the outer edge oE the platform 16
will be located below the back edge of the floor 21 of the truclc.
Thus, by removing the rail 36, i-t is possible to load ancl unload the
truck with the bac~ end OL the truck closely adjacent the loading
dock.
It will also be apparent that when the platform 16 is in
the storage position shown in Figure 2 oE the drawings, the arms 3()
do not extend above the upper edge oE the platform 16 to an extent
greater than one half of the total height of the platform l6 in the
storage position. Thus, it will be seen that the arms 30 do not
represent a major obstruction to overhead canopies or doorway
headers when a truck is backed up to a loading bay. These and other
advantages of the retention fence of -the present invention will be
apparent to those skilled in the art.
