CA2141345A1 - Dock leveler having a ramp movable to a raised position by inflation of an inflatable member, with a filler for occupying volume within the inflatable member - Google Patents

Abstract

DOCK LEVELER HAVING A RAMP MOVABLE TO A RAISED
POSITION BY INFLATION OF AN INFLATABLE MEMBER, WITH A FILLER FOR OCCUPYING VOLUME WITHIN
THE INFLATABLE MEMBER
ABSTRACT OF THE DISCLOSURE
A dock leveler including a ramp is movable to a raised position by inflation of an inflatable member, such as an air bag assembly. One or more filler members are located within an internal cavity defined by the air bag assembly, to occupy void volume therein. The filler members expedite inflation of the bag assembly when an inflating device is operated to introduce air under pressure into the bag assembly. The filler members also function to maintain the bay assembly in an engaged condition with the underside of the ramp, and to prevent the air bag assembly from fully collapsing in order to prolong bag life.

Description

2~ ~034~
. , , , ~ . .;
- 1 - ..
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, :,, ,, ~ ,:......
,. :;, -: ",',::

~ 21~03~ ". ~
. "., . . ;` :,.

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 `-: '. ':' "

. ., \`
j 21~03 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.

''`.''.' ' ''.''.
, , .: .. ( . -. ' ,' '~.

~ 21~03~5 ;: :
.. ..: . .

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. ~;

' `'' .! ~ 2 1 ~ 0 3 ~ ~j -- 5 -- .
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. ;.

;~",, ~- 21~03~l~
.:
- 6 ~
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.

-~:: ,: .

~ 2 1 ~ 0 3 ~ 5 . , 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 ~ ~ 0 3 4 ~

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.

Claims (18)

1. In a dock leveler including a ramp movable between a lowered position and a raised position, an inflatable member located below the ramp for moving the ramp to its raised position upon inflation of the inflat-able member, the inflatable member including an internal cavity and being collapsible, and a selectively operable inflating arrangement for introducing pressurized air to the internal cavity of the inflatable member, the im-provement comprising a filler member located within the inflatable member internal cavity for keeping the inflat-able member from collapsing under its own weight to expe-dite filling of the internal cavity with air upon opera-tion of the inflating device.

2. The improvement of claim 1, wherein the inflatable member comprises an airbag assembly having an upper chamber and a lower chamber, and wherein a filler member is located within each of the upper and lower chambers.

3. The improvement of claim 2, wherein the airbag assembly includes a wall interposed between the upper and lower chambers and one or more openings formed in the wall for establishing communication between the upper and lower chambers, and wherein the filler member includes an opening in alignment with the one or more openings.

4. The improvement of claim 1, wherein the inflatable member includes a wall having an inlet into which pressurized air is supplied upon operation of the inflating device, and wherein the filler member is in engagement with the wall and includes an opening disposed in alignment with the inlet.

5. The improvement of claim 1, wherein the filler member is formed of a foam material.

6. The improvement of claim 5, wherein the inflatable member internal cavity is defined by a pair of spaced walls, wherein the walls are arranged so as to be farther apart at a first end of the cavity than at an opposed second end, and wherein the filler member com-prises a wedge-shaped piece of foam material having a reduced end located toward the first end of the cavity and an enlarged end located toward the second end of the cavity.

7. The improvement of claim 1, wherein the dock leveler includes a surface engageable by the inflat-able member where the inflatable member is inflated to raise the ramp, and within the filler members functions to maintain the inflatable member in contact with the surface.

8. For a dock leveler including a ramp movable to a raised position by operating an inflating device to fill an inflatable member with air, a method of expedit-ing filling of the inflatable member with air, comprising placing a filler member in the inflatable member for occupying space within the interior of the inflatable member.

9. The method of claim 8, wherein the inflat-able member comprises an airbag formed from a sheet of folded material having a first seamless end defined by the fold of the material and a second end defined by overlying end portions of the sheet of material, and wherein the step of placing a filler member in the in-flatable member comprises placing the filler member on a surface of the sheet of material, folding the sheet of material over the filler member, and subsequently secur-ing the overlying end portions of the sheet of material together.

10. The method of claim 8, wherein the step of placing a filler member in the inflatable member compris-es placing a filler member constructed of a foam material within the inflatable member.

11. The method of claim 8, wherein the inflat-able member includes an inlet for communicating air to the interior of the inflatable member, and further com-prising forming an opening in the filler member such that the opening is disposed in alignment with the inlet.

12. A dock leveler assembly, comprising:
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 inflatable member to raise the ramp; and a filler located within the inflatable member for occupying space therewithin to expedite filling of the inflatable member with air upon operation of the inflating device.

13. The dock leveler assembly of claim 12, wherein the ramp defines a downwardly facing surface with which the inflatable member is engageable to move the ramp to its raised position upon operation of the inflat-ing device to inflate the inflatable member.

14. The dock leveler assembly of claim 13, further comprising a support spaced below the downwardly facing surface of the ramp, wherein the inflatable member is disposed between the support and the downwardly facing surface, and wherein the filler functions to maintain the inflatable member in a position in which the inflatable member substantially fills the space between the support and the downwardly facing surface to prevent entry of debris or other objects between the inflatable member and the ramp downwardly facing surface.

15. The dock leveler assembly of claim 14, wherein the filler member functions to maintain an upper surface of the inflatable member in engagement with the ramp downwardly facing surface.

16. The dock leveler assembly of claim 14, wherein the inflatable member includes an upper chamber and a lower chamber, and wherein a filler is located within each of the upper and lower chambers.

17. In an assembly including a member movable between first and second positions in response to intro-duction of pressurized air from an inflating device to an internal cavity defined by a collapsible inflatable member, the improvement comprising a filler disposed within the internal cavity of the inflatable member for occupying space therewithin to expedite inflation of the inflatable member upon operation of the inflating device.

18. The improvement of claim 17, wherein the filler functions to prevent the inflatable member from collapsing when the inflating device is not being operat-ed to inflate the inflatable member.