Roll-away wheel truck and lift table assembly

A system for allowing a wheeled truck to be rolled on and off a vertically extendable lift table assembly, whereby material handling operations between one vertical elevation, and one horizontal location, and the second vertical location, at a second horizontal location, will be facilitated. The roll-away lifting combination herein essentially comprises a vertically extendable lift table assembly with a cooperating wheeled truck assembly that can be selectively superposed, i.e., moved on or off, a lift table assembly which in turn allows the entire assembly to be conveniently moved from one horizontal location to another. The lift table itself preferably has a double scissor-jack linkwork, which allows the wheeled truck to be raised, for example, to heights of approximately seven feet above a horizontal ground reference. The improved roll-away combination taught herein comprises a particular form of mating between at least one horizontally and longitudinally disposed flange and guideway, on the lift table, and an engaging wheel contact means, on the wheeled truck. The present invention teaches a manner of allowing such a modified wheeled truck to be easily positioned upon said lift table, elevated to any vertical level, or moved to any horizontal location. The truck is temporarily retained upon the table by a frictional resistance against longitudinal roll-away of the truck.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
A materials handling system comprising a roll-away wheel truck, and a lift 
table which allows the selective on and off loading of the wheel truck 
assembly, at any horizontal location. The present invention has particular 
utility in a loading dock situation, wherein materials have to be on, or 
off, loaded from a vehicle trailer, at one horizontal location, and one 
vertical elevation, and thereafter transported to a second horizontal 
location, and vertical elevation. The present invention constitutes 
further improvement upon my above-noted copending application, insofar as 
the present mating of the truck and lift table allows for a frictional 
engagement which resists, yet does not totally prevent, roll-away of the 
wheeled truck at any vertical elevation, in addition to a ground 
elevation. 
While lift tables per se are known in the prior art and of course, wheeled 
push-type trucks are also per se well known in the prior art, the present 
invention constitutes a functional and structural improvement which 
greatly enhances the utility of such known types of device. The present 
invention teaches a synergistic cooperation which results from certain 
specific modifications of the wheel truck and the lift table, whereby 
conventional elements have a functional utility together, which neither 
possessed alone, prior to the modification taught herein. 
2. Description of the Prior Art 
The prior art, known to applicant, which is pertinent to the present 
application is adequately discussed in my copending application Ser. No. 
46,521. 
To summarize the state of that prior art, there are known to be various 
forms of elevating truck-like devices, although prior teachings have 
incorporated elevating mechanisms upon wheeled sub-carriages. The present 
invention, as in the case of my copending application, takes a 
categorically different approach. Herein, an otherwise conventional 
wheeled truck is modified so it can be wheeled upon a lifting table which, 
itself, can also be moved to various horizontal locations. Accordingly, 
the present invention has a greater degree of flexibility, in that a 
wheeled truck can be horizontally moved on or off a lift table which can 
be then placed in any desired horizontal location, and thereafter raised 
to any desired vertical elevation. It should be manifestly apparent that 
the present invention departs from prior material handling teachings in 
that only one lifting platform device need be supplied, in order to serve 
a plurality of modified wheel truck assemblies, i.e., several mating wheel 
truck assemblies can be serviced efficiently by one lifting table device, 
as taught hereinafter. The present invention is also novel in the sense 
that a lift table assembly can function as a vertical lifting device at a 
given horizontal location, for a plurality of the modified wheel truck 
assemblies. 
SUMMARY OF THE INVENTION 
A roll-away combination which essentially comprises a vertically extendable 
lift truck assembly and a cooperating wheeled truck assembly that is 
operable to be selectively rolled on or off a lift table assembly, for 
material handling purposes. The lift table assembly itself consists of a 
horizontally extending working platform that is positioned, in the 
vertical sense, by a scissor jack linkwork assembly. In the preferred 
embodiment, a double scissor jack linkwork assembly is taught, in order to 
conveniently allow the lift table to be raised, for example, to heights of 
approximately seven feet above a ground reference. The double linkwork 
mechanism, as well as the lift table itself, are per se conventional in 
the materials handling field. However, the present combination is the 
result of certain specific modifications which synergistically allow a 
cooperative function for a combination; which either a wheeled truck 
assembly, or a lift table, alone, does not contemplate. The preferred 
embodiment requires modification of a lift table working platform with the 
addition of at least one horizontally extending and longitudinally 
disposed flange which cooperates with at least one horizontally extending 
guideway for maintaining a superposed wheeled truck in a frictional 
engagement during any lift table movement. 
The second essential part of the combination, as taught hereafter, is a 
wheeled truck assembly which is conventional, except for certain 
specifically taught modifications. The wheels maintain a load platform at 
a particular first distance above a ground reference, and this first 
distance allows the truck to be horizontally wheeled, in a longitudinal 
direction, so that certain structure on the underside of the truck load 
platform interacts with certain lift table load platform structure. The 
truck assembly can be wheeled, for example, onto a horizontally extending 
flange which extends, in a longitudinal direction, from the working 
platform surface of the lift table. The wheeled truck further includes an 
inwardly open, channel-like structure which longitudinally extends, and 
will vertically surround a horizontally extending guideway that is spaced 
above the flange of the lift table. Accordingly, when the thusly modified 
wheel truck assembly is operably positioned upon that flange, the truck 
will be maintained against any transverse movement by a cooperation 
between the guideway and engaging means on the wheeled truck. Furthermore, 
the guideway is so configured that there will be a relatively slight 
frictional engagement between the horizontally extending guideway of the 
lift table, and at least one surface of an inwardly open channel which may 
define the wheeled truck engaging means. In this fashion, a wheeled truck 
will be maintained, frictionally, as the lift table is either used to 
vertically raise the assembly, or used to move the assembly to a second 
horizontal location. 
It is a primary object of the present invention to teach certain additional 
improvements upon the system taught in my copending application Ser. No. 
46,521, and to particularly also allow a modified wheeled truck to be on 
or off loaded at any vertical elevation desired. It is a significant 
object of the invention to teach a system which essentially requires only 
one relatively expensive lift table assembly to serve a plurality of wheel 
trucks which need be raised and moved in vertical and horizontal 
directions. It is a related object of the present invention to teach a 
manner of modifying certain relatively conventional material handling 
equipment, so as to allow a novel and synergistic cooperation of two 
structures, into a singularly effective lifting combination. 
Other features, advantages and objects of the present invention will become 
more apparent from the detailed description which follows, wherein 
reference is made to the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A novel lift table, and cooperating wheel truck assembly, according to the 
teachings of my parent application is repeated herein at FIG. 1. A wheel 
truck, 2, with handle 10, is in a superposed mating relation upon a lift 
table assembly, 4. The wheel truck 2 is shown directly resting upon a 
working platform, 6; there is an engagement between the under-surface of 
the truck and the top of the lift table, with wheels, 14, 16, freely 
suspended. 
The FIG. 1 combination is more particularly taught in parent application 
Ser. No. 46,521, and for that purpose is incorporated by reference, 
herein. By way of summary, FIG. 1 shows a single linkwork assembly, 
wherein a single hydraulic cylinder, 42, urges upward a first link, 34. A 
second link, 32, pivots about a pin connection, 36, with first link, 34. 
Fluid for this scissor jack actuation is supplied through a conventional 
pumping circuit to the hydraulic cylinder, 42, as shown generally at 38, 
with power input being, for example, through an electric receptacle, 40. 
The lift table assembly further comprises a subcarriage support, 18, which 
may be independently moved in any horizontal manner, for placement on any 
ground reference point. As shown in FIG. 1, this earlier teaching includes 
placement of the table 4, and then a superposed mating engagement of a 
wheeled truck at a ground level. Hence, as in FIG. 1, materials can be 
moved from a building platform, 20, directly upon a raised wheeled truck 
which, then is lowered and removed from the lift table assembly. The lift 
table assembly can be horizontally moved by engaging a dolly device under 
the yoke, 24, thereby trailing the entire device by a horizontal bearing 
upon the wheels, 22. Having now reviewed the operation of the device shown 
in FIG. 1, and more particularly described in my copending parent 
application, I will now describe more particularly the present 
improvements as they relate to a roll-away lifting combination. 
FIG. 2 is a preferred embodiment for the roll-away lift table and wheel 
truck assembly which is taught herein, and in certain respects there is a 
similarity of the presently taught invention and the earlier teachings 
which are summarized herein at FIG. 1. 
The present invention departs from the lift table and cooperating wheel 
truck assembly of the parent application in that the present invention 
allows a uniquely modified wheeled truck to be on or off loaded from the 
lift table at any desired elevation. The lift table assembly comprises a 
working platform, 56, which is operable to be vertically extended by a 
scissor jack linkwork assembly, illustrated generally at 68. A double jack 
linkwork assembly is preferred, to greatly raise the work platform, 56, 
with respect to a lift table sub-carriage, identified generally at 54 in 
FIG. 2. 
The superposed truck assembly, 52, essentially comprises a load platform, 
66, which is normally supported by conventional pivotable wheels, 62, 64. 
Hence, the underside of load platform, 66, is maintained at a first 
distance above any ground reference, and this distance may be chosen to 
allow a certain frictional contact between the wheeled truck and some 
structure of the lift table work surface, 56. The working platform further 
comprises at least one horizontally extending, and longitudinally disposed 
flange, 58, and at least one horizontally extending guideway, 60. When the 
wheel truck is selectively positioned as shown in FIG. 2, the guideway, 
60, and the flange, 58, may preferably define an outwardly open channel, 
with the guideway selectively engaging an inwardly-open channel member of 
the wheel truck, as shown. This inwardly open channel is spaced 
sufficiently above a ground contact level, by the wheels 62, 64, to allow 
the truck assembly to be horizontally wheeled onto the flange, whereby the 
inwardly facing engaging means on the wheel truck will vertically surround 
the horizontally extending guideway, 60, on the lift table. In the 
illustrated, preferred embodiment there is a frictional contact between at 
least one surface of the inwardly open truck guide means, 66, and the 
horizontal lift table guideway, 60. This engagement resists any 
possibility that the wheeled truck, 52, will move while positioned upon 
the lift table assembly, during lift table movement. 
As further shown in FIG. 2, the subcarriage, 54, of the lifting table 
assembly can be moved horizontally by raising a yoke, 78, through a dolly 
service, 86, wherein the subcarriage wheels, 76, will then enable 
horizontal movements of the entire assembly. The preferred embodiment 
illustrates a double scissor jack assembly, shown generally at 68. The 
first linkwork has a first link, 70, which is pivotally attached to one 
link, 72, of a second linkwork. A hydraulic cylinder, 80, urges up the 
assembly by a contact with the link, 72, as by the pivot, 82. The first 
linkwork assembly also includes a second pair of links which have lower 
ends which travel horizontally upon guideways, 74, located as shown within 
the subcarriage, 54. As previously noted, a double scissor linkwork as 
taught herein is per se conventional, and further illustration of this 
aspect of the present combination is not considered necessary. 
FIG. 3 shows an environmental application of the combination taught 
according to the present invention. The material handling problem 
illustrated in FIG. 3 is the off or on loading of a truck bed, 92, which 
is maintained at a given vertical elevation. The operation is shown 
pushing a wheel truck, 52, (modified as taught herein) from the vertical 
elevation, 92, onto the horizontal flange, 58, and into engagement with 
the guideway, 60, of the working platform, 56. Such a longitudinal 
movement of the wheeled truck is ensured by the cooperation of the wheels 
and the engaging means on the bottom or underside of the wheeled truck. 
The lift table sub-carriage, 54, is supported upon a ground reference, 90, 
and may then be moved from that position by conventional use of dolly, 86, 
which raises the entire assembly backwardly and upon the sub-carriage 
wheels, 76. The entire assembly can be moved into any location, for 
example where the exemplary goods, 100, need to be handled. For example, 
and as illustrated in FIG. 3, there may be a protectively enclosed space, 
96, which will allow the present invention to be used as a portable 
elevator device, for raising the load, 100, up to a second vertical 
elevation, 94. The operation contemplates use of a plurality of additional 
modified wheel truck assemblies, 98, with a single lifting table working 
surface, 56. 
Manifestly, the present invention expands the utility of the known wheeled 
truck, by the novel concept of employing a plurality of specifically 
improved wheeled trucks to mate in a particular way, with the upper 
surface of a conventional lift table. The present invention is a roll-away 
lifting combination, which greatly facilitates material handling in a 
warehouse type environment, since a number of modified wheeled platform 
trucks can be used to mate, in a roll-away fashion, with a single lifting 
platform. The present invention does not require a lifting mechanism for 
each truck, nor does the present invention require any involved mechanical 
interactions for initially placing a wheeled vehicle into place on the 
lifting table working platform. 
Since certain adaptations and modifications of the present invention will 
be apparent to those of ordinary skill in this art, it is to be understood 
that the invention is to be limited solely by the scope of the appended 
claims.