Note: Descriptions are shown in the official language in which they were submitted.
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DOCR ~EV~L~R ~a~ A RANP ~OVABL~ TO A RAI8ED
PO8ITION BY IN~ATION O~ A~ LATABL~ ~EMBBR,
WI~U A ~IL~ FOR OCCUPYIN~ VOLUME WI~IN ~ ~ ;
BACKGROUNp ~ND SUMMARY OF THE I~VENTION
This invention relates to a dock leveler, and
more particularly to a dock leveler having a ramp movable
to a raised position by in~lation of an inflatable member
disposed below the ramp.
In accordance with known construction, a dock
leveler typically includes a ramp ~or bridging the space
between a loading dock and the bed of a truck or other
carrier parked adjacent the loading dock. The ramp is
movable between a horizontal rest position and an in-
clined raised position. A lip is mounted to the outer
end of the ramp, and is disposed in a pendant inoperative
position when the ramp is in its rest position. Ater ~ -~
the ramp is moved to its raised position, the lip is
moved to an extended position and engages the truck bed
upon subsequent downward movement of the ramp to support
the outer end of the ramp.
Recent developments in dock leveler technology
have involved utilizing an inflatable member, such as an
airbag, to lift the ramp to its xaised position. Copend-
ing U.S. Patent Applications S.N. 08/131,981 filed Octo~
ber~4j 1993 and S.N. 08/131,983 filed October 4, 1993, as
wel~l as copending U.S. Patent Application ;~ -
filed ~ , disclose dock levelers of
this type, and the disclosures of thes~ applications are
l hereby incorporated~by reference.
he inflatable member or airbag is inflated
using an inflating device, which can be any source of
pressurized air. In one form, a fan or blower is mounted
to the airba~ support or to the ramp, and supplies low~
35 pressure air to the interior of the airbag assembly to ~;~
inflate the airbag assembly and to raise the ramp. As
can~be appreciated, when the fan or blower is operated,
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it has in the past been necessary to supply a sufficient
quantity of air to the interior of the airbag assembly to
completely occupy the entire volume defined by the inte- `
rior of the airbag assembly in order to introduce suffi-
cient pressure to the air to raise the ramp. This re-
quired the fan or blower to operate for several seconds ~;
without any movement whatsoever of the ramp, before the ;
airbag assembly was filled with a sufficient quantity of
pressuri2ed air to commence lifting of the ramp.
In addition, the airbag ~ssembly is typically ;~ ~;
constructed such that, when pressurized air is removed
from the interior of the airbag assembly, the airbag
assembly moves to a collapsed position under its own
weight. This created a space below khe ramp between the
15 upper surface of the airbag assembly and the underside of ;
the ramp. This space could collect debris or other
objects, creating the potential for puncturing the airbag ;-
upon inflation of the airbag and engagement with the
underside of the ramp. - ~ ;
~ 20 It is an object of the present invention to
; provide a means for expediting filling of the inflatable
member of a dock leveler with air upon operation of an
inflating device. It is a further object of the inven~
tion to provide such a means which does not affect the
overall structure or construction of either the inflat-
able member or any other component of the dock leveler.
A still Purther object of the invention is to provide a ~-
means for maintaining the inflatable member in engagement
with the underside of the ramp in order to eliminate the
; 30 l space between the bag and the ramp in which debris or
other objects can collect.
In accordance with the invention, a dock level-
er assembIy includes a ramp movable to a raised position
from a lowered position, an inflatable member located
below the ramp, an inflating device interconnected with
the inflatable member for introducing air into the inte- ;~
rior of the inflatable member to raise the ramp, and a
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filler member located within the interior of the inflat-
able member. The filler member functions to maintain the
inflatable member in a non-collapsed condition, in order
to reduce the amount of air which must be introduced into
the inflatable member in order to inflate the inflatable
member and raise the ramp. The filler member may take
any satisfactory form~ In one embodiment, the filler
member is constructed of a resilient foam makerial, which
is placed into the interior of the inflatable member upon
assembly of the inflatable member. The foam filler
prevents the inflatable member from collapsing, thus,
~;~ retaining air therewithin which would otherwise be ex-
~; hausted if the inflatable member were to collapse~ This
functions to significantly reduce the volume of air which
~15 must be intr~duced into the inflatable member in order to -~
raise the ramp. In an application where the inflatable
; member is not secured to the underside of the ramp, the
filler member is constructed so as to maintain~the upper ~ ~;
portion of the inflatable member in contact with the
underside of the ramp when the ramp is in its rest or
oper~tive position, in order to prevent debris or other -~
objects from coming between the ramp and the inflatable
member. In an arrangement in which the inflatable member `
has more than one chamber, a filler member is placed in
25 each chamber of the inflatable member to prevent ea~h -~
member ~rom collapsing n~ to prevsnt the upper portion
of the inflatable member from blocking openings communi-
cating between thé chambers.
The invention further contemplates a method of
30~ lexpedi~ing filling of an inflatable member in a dock
leveler, or in any other assembly having a member which ~ ~-
is movable to form one position to anothar in response to
filling an inflatable member with air. The method of the ;~
inventlon is substantially in accordance with the forego~
ing summary.
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Various other features, objects and advantages
of the invention will be made apparent from the following ;
description taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate the best mode presently
contemplated of carrying out the invention.
In the drawings:
Fig. 1 is a partial vertical section view of a
dock leveler assembly in which the ramp is raised upon
inflation of an airbag assembly, and incorporating filler
members for exp diting inflation of the bag assembly in
accordance with the present invention;
Fig. ~ is an isometric view of a member for
placement into the interior of the bag assembly for the
;15 dock leveler assembly of Fig. 1; and
Fig. 3 is a view similar to Fig. 1 showing the
dock leveler ramp in a lowered position and compression -
of~the filler members.
DETAILED DESCRIPTION OF THE PREFERRED_EMBODI~EN$ ;~
~eferring to Fig. 1, a dock leveler 10 is
mounted in a pit or depression 12 in a loading dock. The -~`;
lower~surface or floor 14 of pit 12 slopes downwardly and
forwardly, in a conventional manner. Dock leveler 10 is
` ~ ~ adapted to bridge the gap between the upper surface of ~ `
25 the loading dock and the bed of a truck or carrier parked ;
in~front of the loading dock, to facilitata loading or
unloading of the truck or carrier.
Dock leveler lO includes a frame or supporting
structure 16 mounted in pit 12, an~ the rear end of a
30~ ramp or deck plate 18 is pivotably mounted to the upper
end of frame 16 via one or more pins 20, again in a
conventional mannerO~ Ramp 18 is movable between a gener-
ally horizontal ~oe~ leval position as shown in Fig. 3,
in which ramp 20 is flush and substantially coplanar with
the upper surface of the loading dock, and an upwardly
inclined raised po~ition as shown in Fig. 1. ~;
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In a conventional manner, an extension lip (not
shown) is hinged to the forward end of ramp 18 via hinge
pins or the like. The extension lip is pivotable from a
pendant position to an outwardly extending position via a :
lip extensi~n mechanism which is actuated when ramp 18 is
moved to its raised position of Fig. 1 and then lowered.
~ When the lip is moved to its outwardly extending posi-
: tion, the lip is coplanar with ramp 18, forming an exten-
sion to ramp 18. The lip is moved from its pendant :::
~: 10 position to its extended position by any satisPactory
conventional mechanism, and comes to rest on the bed of
the truck or carrier upon downward movement of the ramp
~:~; from its raised position of Fig. 1 to its horizontal ~ock ~: :level position of Fig. 3. : ;
Ramp 18 is mountsd to a series of beams 22
which extend in a longitudinal front-rear direction
;~ between the forward and rearward ends of ramp 18. A
downwardly facing pressure plate 24 extends across beams ;~.
: 22 toward the rearward ends of beams 22, and is mounted
20 against beams 22 in any satisfactory manner such as by . .
; bolting, welding or the like. ~ `
A lifting assembly 26 is disposed between plate -.
24`and pit floor 14 and includes an infIatable member or .
bag assembly:28 including an upper bag 30 defining an
~ 25~ internal cavity 31 and a lower bag 32 defining an inter~
: ~ : : nal cavity 33. Bags 30, 32 are verticaIly superimposed,
with bag 30 overlying bag 32. Lifting assembly 26 fur~
: ther:includes a bag support assembly 34 and an inflating -~:.. ;
device in the form of a fan or blower 36. Bag support 34 ~.
30 ..l includes;a support plate 38 defining an upper surface ~
engaging the lower wall of lower bag 32 and a series of ` 5. ' -~} '
wheels 40 mounted to the forward end of bag support 34 .
and engaged with pit floor 14. A pin or shaft 42 is `.
: provided at th~ rearward end of bag support 34, and is
35 ~ received within a series of upwardly facing slots 44 .-
formed in bracket members 46 extending downwardly from .
the rearward end of ramp 18. ;.
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Fan 36 is mounted to a lower surface defined by ~ -
support plate 38 or, in any other satisfactory location,
and a pipe assembly 48 extends between the discharge of ~ ;
fan 36 and the interior of lower bag 32. Alternately,
pressurized air can be supplied to bag assembly 2B from
any satisfactory source, such as pressurized shop air.
Pipe assembly 48 includes a discharge nipple 50 which
extends through aligned openings formed in support plate
38 and in the lower wall of lower bag 32, with nipple 50
10 having its end disposed within internal cavity 33 of ~ ;
lower bag 32. Nipple 50 is provided with outer barbs 54
which engage a flexible molde~ mounting ring 52, such ~s
~lexible PVC, secured to the lower wall 63 of lower bag ;; ;i
32. ;-
The construction of bag assembly 28 is illus-
trated and described in copending United States patent
application S.N. 08/131,981 filed October 4, 1993. Bags :~;
30, 32 are preferably formed of fabric coated with a
thermoplastic resin. Bags 30, 32 have contiguous hori-
20 zontal walls 56, 58, respectively, in which aligned -
openings 60 are formed to establish communication between -
the internal cavities 31, 33 of bags 30, 32, respective- ~
~' ly. :, `.'',':,
; The upper surface of upper bag 30, defined by
an upper wall 62, bears against pressure plate 24 and the
lower surface of lower bag 32, defined by a lower wall
63, bears against support plate 38, for raising ramp 18 ;
to its raised position of Fig. 1, as will be explained.
Filler members 64 are located within internal ~-
l cavity~31 defined by upper bag 30 and internal cavity 33
defined by lower bag 32, respectively. Filler members 64
are wedge-shaped, with each defining a front surface 66,
a rear surface 68, a top surface 70 and a bottom surface
72. Front surface 66 has a height significantly greater
than rear surface 68. Filler members 64 are constructed
so as to occupy a majority of the volume defined by bag
internal cavities 31, 33.
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Filler members 64 each include a cut-out 74
extending between lower surface 72 and upper surface 70
forwardly from rear surface 68. Each cut-out 74 extends
throughout the central portion of rear wall 68. Cut-outs
74 are in co~iunication with the discharge of outlet
nipple 50, and with openings 60 in bag walls 56, 58.
Filler members 64 are placed into cavities 31, ~ ;
33 before the rear ~nds of bag walls 56, 58, 62 and 63
are brought into overlying relationship with each other ;~
10 adjacent the rea ~ ard end of support 34 by folding the ~;;
material of bags 30 and 32, at which time fillers 64 are
secured within cavities 31 and 33. The rear ends of bag ~;
walls~56, 58, 62 and 63 are then secured to support plate ;~
38 using a clamp bar 78 and a series of bolts 80 and ~-;
15~ associated nuts, or by any other satisfactory mounting
method.
Fig. 2 illustrates a filler 64 prior to place- ;;
mènt within bag cavities 31 and 33. Filler 64 is pref- ~ ;~
erably formed from~a block of resilient, compressible .`,
~open cell foam material.
In operation, dock leveler 10 and filler mem~
bers 64 function as~follows. ~ en ramp 18 is in its at~
rest~position not~supported by~bag assembly 28, in which
ramp~18 can either be in a horizont~l position or a non~
25 horizontal positionl filler members 64 maintain airbag ~ `~
assembly~28 in a raised, non-collapsed position in which
bottom wall 63 of lower bag 32 in engagement with support '~
plate 38 and the~forward end of upper bag 30;top wall 62 ~-;
is in engagement with the lower surface of pressure plate ;;
30j~l 24.~ In this~!manner, there~is no gap or spaceidefined
between bag upper wall 62 and pressure plate 24, which
could~otherwise~catch~debris or~other ob~ects which couId ~m~
puncture~ bag 30~upon inflation. Bag assembly 28 is then
inflated by operation of fan 36 or other means, during
which air~is introduce~ into the interior of lower bag 32
through the discharge of outlet nipple 50. Such air is ` i;~
received~in cut-out 74 of lower bag 32, and then passes
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through openings 60 into upper bag 30. Bags 30 and 32
are then fully inflated by continued operation of blower
36, to lift ramp 18 by engagement of bag assembly 28
between support plate 38 and pressure plate 24 and by
5 pressured air within internal cavities ~1, 33. Fillers ~ ;;
64 reduce the idle time which would otherwise be neces-
~ary to inflate air bag assembly 28 from its collapsed
position~ thus sub~tantially expediting the rai~ing of
ramp 18. Once ramp 18 is fully raised, operation of fan
36 is discontinued and ramp 18 is lowered to its Fig. 3
position in which the lip mounted thereto is supported by
the truck bed. During such lowering of ramp 18, air is ;~
exhausted through fan 36, and filler members 64 are
compressed to the position a- shown in Fig. 3. ~t all
15 times, filler members 64 function to prevent bags 30 and ~ ;~
32 from fully collapsing, thus preventing bags 30 and 32
from folding and to thereby prolong bag life. Upon ;; -~
subsequent inflation of bags 30, 32, filler members 64
return to their expanded condition as shown in Fig. 1 due
to the resiliency o~ the material making up filler mem-
bers 64.
It is understood that air bag assembly 28 could
be in any form of inflatable member and have any number
of chambers, and that any form of filler member could be
used to keep the inflatable member from collapsing and to
expedite inflation of the inflatable member.
It is further understood that any void-occupy-
ing structure could be used in place of foam filler
members 64, and that the invention contemplates numerous
30 ~l other embodiments not specifically shown or discussed.
Various alternatives and embodiments are con-
templated as being within the scope of the following
claims particularly pointing out and distinctly claiming
the subject matter regarded as the invention.
