Dock leveler with integral bumpers

A dock leveler mountable in a pit including a rear wall, the leveler including a deck with a front end and that is capable of pivotal movement relative to the rear wall; a lip capable of movement to a substantially coplanar position relative to the deck; and a bumper mounted adjacent the deck front end beyond the lateral width of the lip.

FIELD OF THE INVENTION 
The present application discloses a dock leveler, and particularly a dock 
leveler including a widened deck member carrying integral dock bumpers. 
BACKGROUND OF THE INVENTION 
Dock levelers are widely used to facilitate the loading and unloading of 
vehicles at a loading dock. The dock leveler forms a bridge between the 
building, such as a warehouse or distribution facility, and the back end 
of the vehicle being loaded or unloaded. A gap typically exists between 
the building exterior wall and the rear end of the vehicle by virtue of 
the fact that the vehicle engages against bumpers on the exterior wall. 
The bumpers are disposed on the wall to protect both the vehicle and the 
wall against the damage that would result from the vehicle directly 
engaging the wall. A set of bumpers B, disposed on either side of a dock 
leveler D, are shown in the prior art FIG. 1. To bridge the gap thus 
formed, a dock leveler typically employs a deck member, labeled M in FIG. 
1, that is hingedly connected about its rear end at H to a support 
structure disposed within a pit P. Hingedly connected to the front end of 
the deck D is a lip L which is movable between a downwardly hanging, 
stored or "pendant" position and the extended position shown in FIG. 1. In 
the extended position, the lip would be placed in the rear of the vehicle 
being loaded or unloaded to bridge the gap from the vehicle into the 
building, and to facilitate loading and unloading. The hinged connection H 
of the deck to the supporting structure allows the entire leveler to move 
up and down with the vehicle as it is loaded and unloaded. As a vehicle is 
unloaded its suspension will tend to raise the floor of the vehicle, and 
thus the leveler itself. Similarly, as a vehicle is loaded the weight of 
the cargo will tend to depress the floor of the vehicle against the 
suspension. Dock levelers are also vertically adjustable in this manner as 
vehicles are disposed at a wide variety of heights relative to the 
roadway. 
In a typical installation, a pit is formed for receiving the dock leveler. 
The pit is indicated generally in FIG. 1 by the reference letter P. The 
pit provides space for the leveler itself, as well as for the actuation 
mechanism for raising and moving the leveler into its operating positions, 
and returning it to a stored position. The dock bumpers B are typically 
disposed on the vertical exterior building wall just laterally of the pit 
sidewalls. Under certain conditions, this arrangement can be problematic. 
In FIG. 1, the dock leveler is shown in a so-called below dock position. 
That is, the deck is disposed at a declined angle with respect to the 
floor F surrounding the pit P. As can be seen from FIG. 1, the front wall 
W of the building and the side wall S of the pit P thus form ledges at the 
front and side edges of the deck, respectively. Certain vehicles to be 
loaded or unloaded with the leveler may be wider than the width of the 
dock leveler. In such a situation, the presence of the ledges when the 
deck is in a below dock position may be a significant impediment to 
unloading the vehicle. For example, if a load were being removed from a 
vehicle with a fork truck disposed on the leveler in FIG. 1, and if that 
load had a width such that a portion of it extended beyond the lateral 
edge of the lip L and if, for example, there were insufficient headroom 
inside the vehicle preventing the load from being elevated, that cargo 
could strike the front wall W of the loading dock or the bumper B, leading 
to damage of the cargo and/or impeding the efficiency of the unloading 
process. For this reason, facilities that service a large number of wide 
vehicles (i.e., vehicles wider than the width of standard dock levelers) 
often employ truck levelers. Truck levelers are lifts that can lift the 
vehicle to a raised position relative to the loading dock, so that the 
vehicle can be serviced by a dock leveler without the need for the dock 
leveler to assume a below dock position as in FIG. 1, thus avoiding 
interference between the cargo and the dock wall W or bumper B. The 
problem of the front wall of the building and the side wall of the dock 
leveler pit forming a barrier to free and easy movement of cargo being 
loaded and unloaded could also be solved simply by having a dock leveler 
of a wider width. However, if a standard dock leveler were as wide a the 
vehicle itself, there would not be dock wall available for the purpose of 
mounting bumpers. Thus, there would be the risk that the vehicle would 
back directly into the leveler, damaging both the leveler and the vehicle 
itself including impeding the functionality of the dock leveler. 
SUMMARY OF THE INVENTION 
There is thus provided a dock leveler preferably of increased width, and 
which includes integrally-mounted bumpers. In a preferred embodiment, the 
deck of the dock leveler is wider than the lip, with the leveler extending 
laterally beyond the width of the lip on each side. Mounted to the front 
end of the deck, and disposed laterally to the lip, are the integral 
bumpers. These bumpers extend from the front end of the deck to a 
significant projection in front of the lip to ensure that the parking 
vehicle cannot back into the lip as it approaches the dock. A spacer 
member may preferably be included in the bumper assembly. Such a spacer is 
disposed adjacent the front end of the deck. The remainder of the bumper 
assembly is then mounted to the spacer member. The spacer insures that the 
bumper is disposed in front of the lip when the lip is in a pendant 
position to maintain a gap between the rear of the vehicle and the pendant 
lip. The spacer member may preferably include an access hole to allow 
insertion and removal of the hinge pin which hinges the lip to the deck. 
Alternatively, the spacer may be provided with an access notch for the 
hinge pin. Since the bumpers integrally carried on the deck will now be 
subject to the impact of the backing truck, which impact would 
conventionally be dispersed into the building wall, the dock leveler 
disclosed herein preferably includes a bumper support structure to absorb 
and distribute the additional forces exerted on the dock leveler by the 
vehicle contacting the integral bumpers. In a representative embodiment, 
the support structure includes a structural member disposed between a rear 
portion of the deck and the upstanding rear wall of the dock leveler pit. 
The dock leveler with integral bumpers disclosed herein assists in solving 
the problems typically associated with loading and unloading vehicles 
having a width greater than the width of the dock leveler, particularly in 
below dock situations. At the same time, it provides a solution that is 
economical, simple of construction that does not require a significant 
number of moving parts, and can provide a larger, unimpeded maneuvering 
surface for enhancing lift truck operation and safety.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Dock leveler 10 including integral dock bumpers 20 is depicted in FIGS. 2 
through 4 in an operative, below-dock position; an operative above-dock 
position; and a stored position, respectively. It will be apparent to one 
of skill in the art that the above and below dock positions in the Figures 
are representative, and that more extreme deck angles are possible, as 
levelers are typically capable of operating from 12 inches (30.5 cm) above 
to 12 inches (30.5 cm) below dock level. In FIG. 2, the leveler 10, 
including a deck 30 and a lip 40, shows lip 40 in the extended position 
relative to the deck 30. The term "deck" as used herein is intended to 
encompass not only the plate over which traffic passes, but ineed the 
various supporting structure (stringers, I-beams, headers, gussets and the 
like) making up the entire re-enforced platform. Much of the supporting 
structure included in the "deck" is seen most clearly in the plan view of 
FIG. 5. Returning to FIGS. 2-4, it will be appreciated by one of skill in 
the art that with lip 40 in the extended position as shown in FIGS. 2 and 
3, it will typically be disposed on the vehicle being loaded and unloaded 
to bridge the gap between that vehicle and the deck 30. The vehicle is not 
shown in FIGS. 2-4. As a comparison of FIG. 2 to prior art FIG. 1 reveals, 
the provision of the wide deck 30 with integral bumpers 20 mounted at the 
front end thereof, serves to widen the effective operating area of the 
dock leveler. In previous levelers like that shown in FIG. 1, below dock 
loads extending laterally beyond the width of the lip, and that could not 
be elevated above lip 30 because of space or equipment limitations, could 
not be withdrawn from the vehicle because of the presence of the barrier 
presented by the vertical dock wall W upon which the dock bumper B had to 
be mounted. Extending the deck laterally and mounting the bumpers 20 on 
that extended width eliminates this problem or conventionally-mounted 
bumpers. That is, loads can now extend laterally beyond the width of the 
lip without being exposed to the barrier of the dock wall itself, since 
the bumpers are now fixed in position at or slightly beneath the level of 
the deck, regardless of the deck's orientation. At the same time, the 
necessary and desirable functions of dock bumpers (protecting the vehicle 
and the dock equipment from damage caused by impact between the vehicle 
and that equipment and properly spacing the vehicle relative to the 
leveler to allow proper leveler operation) are realized. 
FIG. 3 shows the leveler 10 including integral dock bumpers in an 
above-dock position. The wider deck 30, as compared to a prior art 
leveler, gives the dock attendant a wider area over which to travel and 
operate without being concerned for running off the edge of the leveler at 
the step formed by the deck 30 raised above the dock floor D. Again, in 
prior art configurations where the desired separation between the dock 
bumpers required a narrower pit, this operating width of the upper deck in 
an above-dock position was more narrow. 
FIG. 4 shows the leveler 10 in the stored or "cross-traffic" position where 
the top of the deck 30 is coplanar with the surrounding dock floor D and 
the lip 40 is in its folded or pendant position. The integral dock bumpers 
20 extend forward of the folded lip 40 so that the vehicle approaching the 
loading dock will engage in impact against the bumpers 20 and remain 
spaced from the remaining components of the dock leveler when in the 
parked position. 
A more detailed view of leveler 10, including integral dock bumpers 20 is 
shown in the top plan view of FIG. 5. The leveler 10 is shown with the lip 
40 in its folded position relative to deck 30. The hinged connection 35 
between lip 40 and deck 30 is also shown. In order to place integral dock 
bumper 20 in a position in front of lip 40 (to the left in the sense of 
FIG. 5), the bumper may illustratively include a spacer member 60. The 
spacer member 60, as will be described in greater detail below, is 
illustratively mounted directly on the structure of deck 30. A base plate 
70 for the integral bumper is then mounted to the front face of spacer 
member 60. The contact member 80 of the integral dock bumper is then 
mounted on the base plate 70 in a way to be described in greater detail 
below. As a result, bumpers 20 have a contact surface for the approaching 
vehicle disposed forward of the lip 40 and which will maintain a space 
between the rear of the vehicle and the lip 40 once the vehicle engages 
against the bumpers 20. 
Further detailed views of the mounting of integral dock bumper to the deck 
30 are shown in FIGS. 6 and 7. In the top detail view of FIG. 6, it can be 
seen that in this embodiment the spacer member 60 is an open rectangular 
tube. Illustratively, that tube 60 is welded to a front header 32 of the 
deck 30. Header 32 is simply a plate of structural steel that is typically 
dependent perpendicularly from the deck 30, and to which are mounted the 
hinge spools 33 which mate with similar hinge spools on the lip to form 
the hinge 35 between the lip 40 and the deck 30. It is to this header 32 
that spacer member 60 is welded. Given that the vertical extent of the 
spacer member 60 extends beyond the vertical extent of the header 32, a 
gusset plate such as 36 may be welded to the bottom of the header 32 to 
give enhanced structural support to the spacer member 60 since it will be 
assisting in absorbing and transferring the impact of the backing vehicle. 
FIG. 7 also shows that the gusset plate 36 is further supported by an 
additional structure member 38 welded between the gusset plate 36 and an I 
beam 39 welded to the under side of the deck 30. These components, header 
32, gusset plate 36, structure member 38, and I beam 39 form a front 
portion of a bumper support structure 100, to be discussed in further 
detail below. 
As shown in FIGS. 6 and 7, spacer member 60 is disposed adjacent to hinge 
spool 33 on the header 32. To assemble the lip 40 to the deck 30, the 
complimentary hinge spools on the deck and lip are aligned and a hinge pin 
is then passed through the hinge 35 to secure the two members together. 
The spacer member 60, being disposed just adjacent to the last hinge spool 
33 on the header must therefore include some access to the aligned hinge 
spools so that the hinge pin can be inserted. Similarly, access to the 
hinge spool is important in the event that the hinge pin needs to be 
removed for the purpose of repairing or servicing the dock leveler. Toward 
that end, spacer member 60 includes a hinge pin access hole 62 which is 
aligned with the central opening in the hinge spool 33 to allow hinge pin 
HP (shown being withdrawn in FIG. 6) to be inserted and withdrawn into the 
hinge 35 as desired. 
Alternatively, spacer 60 may be notched or vertically truncated to allow 
access to the hinge pin, as shown in FIGS. 12 and 13. One of skill in the 
art will appreciate that other means of providing access to the hinge pin 
through bumper 20 are possible. 
Returning to FIG. 6, it also shows the remainder of the bumper structure in 
greater detail, comprising back plate 70 and contact member 80. The 
presently-preferred bumper configuration for the integral bumper on the 
dock leveler 10 is one having a construction similar to a dock bumper sold 
by Rite-Hite Aftermarket Corporation under the model name "Dok-Saver" 
bumper. In such a construction, contact member 80 is a formed steel box 
with an opening in the back. Base plate 70 includes a mounting structure 
that protrudes into the contact member 80 through the opening in the back. 
An elastic material (not shown) in the interior of the contact member 80 
helps to dissipate the force exerted on the bumper 20 by contact with the 
vehicle, and helps bias the contact member 80 outwardly with respect to 
the base plate 70. 
To facilitate insertion and removal of the integral bumper 20 from its 
position between the rear of a parked vehicle and the leveler, the front, 
contact surface 85 of the contact member may be tapered from top to 
bottom, as seen most clearly in FIG. 8. In operation, leveler 10 will 
typically be in the stored position (FIG. 4) when the vehicle backs into 
the dock. Although the vehicle V will typically "bounce" off of the 
bumpers, it is possible for the vehicle V to park with a portion of the 
vehicle "snug" to the bumpers, as shown in FIG. 8. To allow the lip 40 to 
attain its extended position relative to deck 30, the deck is typically 
raised upward until the lip 40 clears the vehicle, at which time lip 40 is 
extended, and deck 30 and extended lip 40 move downward to engage the 
vehicle. With vehicle V tight against bumpers 20, upward rotation of deck 
30 could be hampered by frictional engagement between the vehicle and a 
front surface of bumpers 20. Tapering of surface 85 minimizes this 
problem. 
Moreover, this tapering facilitates downward movement of the deck 30 and 
extended lip 40. If vehicle V slips backward (to the right in the sense of 
FIG. 8) when the deck is raised, it may be necessary to wedge bumpers 20 
back into the gap between the vehicle and the building wall. Tapering of 
surface 85 allows for such wedging as it forms a camming surface tending 
to move vehicle V away from the dock as the deck 30 is lowered. It may be 
advantageous or necessary in certain applications to power deck 30 
downward in order to force the bumpers 20 back into the gap. One of skill 
in the art will appreciate that the size of this gap may vary between the 
two bumpers due to such factors as the level and grade of the driveway, 
whether the vehicle is parked or approaching square to the dock, and the 
structural irregularities of the vehicle itself. 
To assist leveler 10 in absorbing and dispersing the impact forces caused 
by the vehicle impacting bumpers 20, a bumper support structure 100 may be 
included. Preferably, the support structure 100 is disposed between the 
portion of the deck behind the bumpers 20, and the rear wall RW of the pit 
P. Support structure 100, illustratively includes: I-beam 39, cooperating 
with front structure shown in FIGS. 6-8, and the rear structure shown in 
FIGS. 9 and 10. FIGS. 5 and 6 shows the widened deck section 31 to which 
one of bumpers 20 is mounted. FIG. 9 shows a detailed plan view of the 
rear portion of that section 31, and the rear portion of support structure 
100, and FIG. 10 shows it in perspective. Conventionally a rear angle R.A. 
is fixed to the corner formed by the rear wall of the pit P, and the 
surrounding floor. Rear angle RA is thus an extension of the rear wall RW 
of the pit P. The support structure 100 in FIGS. 9 and 10 includes a 
bearing or force distribution member in the form of a cylindrical rod 110. 
Rod 110 is disposed between the rear end of deck 30 and the rear wall RW 
of the pit P (i.e., rear angle R.A.). Rod 110 is mounted to deck 30 by 
being welded to a section of rear header 120 depending from and mounted to 
deck section 31. Other means of mounting rod 110 to deck 30 will be 
apparent to one of skill in the art. Disposed between rod 110 and affixed 
to rear angle R.A. are plates or shims 130, 131. These plates 130, 131 
help to distribute the impact forces on deck 30 across the rear wall RW of 
the pit P, and also serve to ensure a bearing engagement (i.e., no gaps) 
between rod 110 and the rear angle R.A. Round stock 110 was chosen as the 
preferred structure for the bearing or force distribution member as it 
gives the most consistent bearing engagement between the rear of the deck 
30 and the pit wall, while also minimizing the depression presently 
encountered by fork truck wheels in passing thereover. 
An alternative bearing or force distribution member is shown in FIG. 11 in 
the form of a box beam 110'. While an even smaller depression is formed as 
compared to rod 110, one of skill in the art will appreciate that the 
square corners of this structure may cause undesirable friction and 
binding with plates 130', 131' as the deck 30 pivots up and down about its 
rear hinge. 
There have thus been disclosed dock levelers having integral bumpers 
disposed on a front edge of the deck beyond the width of the lip. A bumper 
support structure is disposed between the bumper and the rear of the pit 
to assist in distributing and dispersing impact forces on the bumpers into 
the surrounding pit.