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Patent Abstract
A hand truck with an integral load restraining device comprised
of an uptight frame with a handle area, a toe plate which extends
forwardly from the bottom of the upright frame and a pair of wheels
mounted on the lower rear of the upright frame. Hand truck is equipped
with integral universal clamping system arranged for restraining
loads of varying geometric configurations back and against the upright
frame of the hand truck. The integral clamping system is comprised
of a telescoping clamp bar carrying a gear operated load restraining
clamp equipped with universal load gripping fingers. Clamp bar and
clamp telescope inwardly and outwardly to accommodate cargo of varying
depth and are pivotally mounted to a lug inside the vertical slide
track, allowing the clamping system to function over the entire
height of the hand truck, pivot up and down, swing horizontally
from side to side or, be stowed completely out of the way inside
the slide track for conventional use of the hand truck
Patent Claims
What is claimed is:
1. A universal hand truck with integral load restraining device
for transporting loads of varying geometric configuration comprising:
an upright frame, said upright frame having an upper end and a lower
end with a height measured therebetween, said upper end and lower
end being substantially connected by a pair of generally vertical
parallel tube sections with width measured therebetween, said parallel
tube sections being further connected by a handle at said upper
end, and a plurality of cross ties generally equally spaced between
said upper end and said lower end of said upright frame with said
upright frame defining a generally vertical load supporting surface
of said upright frame; a toe plate, said toe plate fixedly attached
to and extending generally perpendicular and forward from said lower
end of said parallel tube sections of said upright frame, said toe
plate defining generally a horizontal load supporting surface; a
pair of rotatably mounted wheels mounted one on either side of said
lower end of said vertical tube sections extend generally rearward
from said lower end of said upright frame; a slide track having
a top end and a bottom end and a length therebetween, said slide
track positioned approximately equidistant and parallel to said
parallel tube sections with said length of said slide track substantially
fixed to said cross ties of said upright frame, said bottom end
of said slide track being substantially connected to top surface
of said toe plate on said lower end of said upright frame, said
slide track providing means for sliding attachment of a coaxial
clamping bar, said coaxial clamping bar to project generally outwardly
from said slide track of said upright frame and travel generally
vertically up or down said slide track between said upper end and
said lower end of said upright frame, said attachment means of said
coaxial clamping bar to be pivotal allowing said coaxial clamping
bar unrestricted vertical, horizontal and angular movement over
length and width of said upright frame said coaxial clamping bar
comprised of a telescoping arrangement whereby a plurality of bar
sections are slidably received one inside the other with provision
for said bar sections to be locked together at a plurality of points
providing a means for adjustment of said coaxial clamping bar to
varying working lengths, a locking clamp arranged to be slidably
positioned and locked at an infinite number of points on at least
one of said bar sections of said telescoping arrangement said locking
clamp provided for with a plurality of downwardly extending load
restraining fingers arranged to apply force to said load restraining
fingers in a backward direction against said vertical load supporting
surface of said upright frame, whereby said outwardly extending
toe plate of said hand truck is slid under a load to be transported,
said coaxial bar and said locking clamp is extended over said load,
said coaxial clamp bar is positioned and locked at a required working
length and said locking clamp with said load restraining fingers
is positioned contacting said load and locked; keeping said load
in position back and against said vertical load supporting surface
and resting on said toe plate when said hand truck is tilted back
locating the load over said wheels in preparation for transport.
2. The hand truck of claim 1. wherein said slide track comprises
a length of tubing having a wall thickness and a circular cross
section, said circular cross section having an inside diameter providing
for a cylindrical shaped sliding lug, said sliding lug being a short
length and of a diameter allowing free sliding contact between said
inside diameter of said slide track and outside surface of said
sliding lug, a forward facing section of said slide track equaling
approximately one sixth of the circumference of said circular cross
section to be open over the length of said slide track providing
a clearance for attachment of said coaxial clamping bar to said
sliding lug, said sliding lug being slotted over it's entire length,
said slot arranged perpendicular to the diameter of said sliding
lug with a depth of approximately two thirds of the way through
the diameter of said sliding lug, said slot having a width dimension
allowing for swivel attachment of said coaxial clamping bar, said
inside diameter of said cross section of said slide track being
of a dimension so as to allow said telescoping coaxial clamping
bar to be received substantially within said inside dimension of
said slide track, said slide track having a plurality of holes arranged
approximately three inches apart over the length of said slide track,
said holes to be approximately five sixteenths inches in diameter
and substantially through both said wall thicknesses of said cross
section of said slide track, said holes to provide for installation
of a stop pin, said stop pin to provide a means for limiting the
travel of said sliding lug inside said slide track when said stop
pin is placed substantially through said holes.
3. The hand truck of claim 2 wherein said telescoping arrangement
comprises a coaxial clamping bar and a clamp said coaxial clamping
bar further comprised of at least one inside bar and one outside
bar, inside bar to be rectangular in cross section and approximately
24 inches long, said inside bar having a plurality of detents cut
into the top surface and along the length of said inside bar providing
means for locking said inside bar to said outside bar at a plurality
of lengths, and an outside bar of hollow tubular cross section;
rectangular in shape and approximately 24 inches in length, inside
geometry of said hollow tubular cross section of said outside bar
allowing for said outside bar to telescopingly receive said inside
bar, said outside bar to have gear tooth profile formed into at
least one outside surface; and over the total length of said outside
bar one end of said outside bar to be equipped with a spring loaded
locking arrangement for interlocking with said detents on said inside
bar providing a means for locking said inside bar and said outside
bar to any one of a plurality of lengths, said locking clamp to
be fitted to said coaxial clamping bar in a manner allowing for
sliding fit of said locking clamp allowing for inwardly and outwardly
sliding of said locking clamp over the length of said outside bar
of said coaxial clamping bar or locking to said tooth profile of
said outside bar at an infinite number of positions over said length
if said outside bar, said clamp to be equipped with load restraining
fingers providing a means for mating with a plurality of geometric
shapes.
4. The hand truck of claim 3 wherein said locking clamp is gear
driven comprised of a body, a clamp handle with gear teeth, a clamp
locking means and a set of flexibly mounted load restraining fingers
said body comprised of a base, a front surface, a back surface and
cheeks which extend vertically from either side of said body; integral
to said body, and arranged to provide a generally rectangular clearance
providing sliding fit for said outside bar of said coaxial clamping
bar therebetween, said cheeks provided with a radius on their uppermost
surfaces with ratchet teeth formed integral to said radius for interfacing
with mating ratchet teeth on said locking clamp, said cheeks of
said body arranged with means for pivotaly attaching said clamp
handle with gear teeth substantially between said cheeks wherein
said gear teeth of said handle will mesh with said geared tooth
profile of said outside bar when said handle is in the engaging
position, said handle with gear teeth pivotally mounted between
said cheeks whereby said handle can be at a first non engaged position
where clearance is provided by a gear heel, said heel of said gear
being void of said gear teeth enabling free bi-directional sliding
movement of said gear driven locking clamp on said outside bar;
or at a second engaged position allowing said gear teeth to mesh
with said geared tooth profile on said outside bar to provide backward
motion and apply a force to said geared locking clamp, said clamp
lock being a spring loaded two position device providing a means
for holding said clamp handle of said gear driven locking clamp
in a locked position, comprised of a hollow square cross section
of tubing with a top end for griping by an operator, a bottom end
with integral ratchet teeth for mating with said ratchet teeth of
said cheeks on said body, inside geometry of said hollow cross section
of tubing of a dimension allowing for sliding fit over said handle,
said top end of said clamp lock arranged for comfortable gripping
and easy lifting motion, said top end of said square cross section
of tubing of said clamp lock substantially closed except for a single
hole providing means for sliding attachment to said handle, said
integral ratchet teeth at said bottom end of said square cross section
of tubing arranged to interlock with said ratchet teeth on said
cheeks, said interlock to be provided by a spring positioned between
said handle and said top end of said clamp lock, said spring arranged
to apply force to said clamp lock in a downward direction maintaining
said interlock between said ratchet teeth on cheeks and said ratchet
teeth on bottom end of said clamp lock, load restraining fingers
provided with means for substantial attachment to said body of said
clamp, comprised of inverted "U" shaped fingers arranged
to extend downward from said clamp body providing means for substantial
contact with said load; transmits force applied by said locking
clamp to said load, said load restraining fingers to be of a material
allowing said fingers to flex when said clamp handle is moved to
said second engaged position and said force is applied to said load
5. A track mounted, telescoping, gear actuated load clamping device
for hand trucks comprising: an upright frame whereto said load clamping
device is substantially attached, said upright frame having an upper
end and a lower end with a height measured therebetween, said upper
end and lower end being substantially connected by a pair of generally
parallel vertical tube sections with width measured therebetween,
said parallel tube sections being further connected by a handle
at said upper end, a toe plate fixedly attached to and extending
generally perpendicular and forward from said lower end of said
parallel tube sections of said upright frame, a plurality of cross
ties equally spaced between said upper and said lower ends of said
upright frame with said cross tie ends fixedly attached to back
side of said parallel tube sections between said upper end and said
lower end of said upright frame, said vertical parallel tube sections
of upright frame defining a generally vertical load supporting surface,
and said toe plate of said upright frame defining a horizontal load
supporting surface, two rotatably mounted wheels mounted on brackets,
one on either side of said lower end of said upright frame, said
brackets extend generally rearward from said lower end of said upright
frame allowing for rolling engagement of said wheels when said upright
frame is tilted backwards, a single track carrying a short cylindrical
shaped sliding lug internally providing means for sliding attachment
of a telescoping, coaxial bar mounted gear clamp, said single track
is fixedly attached to top side of said toe plate, and extends generally
vertical on said upright frame to a point slightly above uppermost
said cross tie and is fixedly attached to each of the said cross
ties approximately equidistant between said vertical tube sections,
said track is circular in cross section, substantially forward facing
portion of said cross section equal to approximately one sixth of
the circumference of said circular cross section removed over entire
length of said track providing clearance for attachment of telescoping
member of said gear actuated load clamping device to said internally
carried cylindrical shaped sliding lug, said sliding lug to be slotted
lengthwise perpendicular to it's diameter with slot geometry arranged
to accommodate use of a pin providing a means to pivotally join
one end of said telescoping coaxial bar to said slot of said lug,
Said single track provided for with a plurality of holes arranged
for receiving a stop pin; providing a means for restricting the
sliding travel of said lug within said track, a telescoping coaxial
bar pivotally attached at one end to said sliding lug providing
variable length arm for mounting said gear clamp, said coaxial bar
arranged for an inner bar to be telescopically received by an outer
bar; one inside the other; with provision for said bar sections
to be locked together at a plurality of points providing a means
for adjustment of said coaxial bar to a plurality of working lengths,
said outer bar of said coaxial bar having geared tooth profile on
the top surface arranged to mesh with gears of said gear actuated
load clamping device, said gear actuated load clamping device arranged
to slidably fit over said outer bar of said coaxial bar and arranged
to provide a backwardly directed restraining force to said load,
said gear actuated load clamping device provided with spring loaded
locking and actuating handle, said actuating handle arranged for
comfortable griping by operator, said handle having a first position
providing means for free slide positioning of said gear actuated
load clamping device; and a second position providing engagement
of said tooth profile of said outside bar and said gear on said
clamp providing a means for gear actuated movement of said clamping
device; applying load restraining force back and toward said vertical
load supporting surface, a means for locking said clamping device
at an infinite number of points on said outside bar of said coaxial
clamping bar, said clamping device having a set of downwardly extending
load restraining fingers arranged to mate with a plurality of geometric
load configurations and apply load restraining force to said load
in a direction backwardly and against said vertical load supporting
surface of said upright frame, wherein said track mounted telescoping
gear actuated load clamping device extends outwardly from said slide
track of said upright frame, providing for a load restraining device
that can apply a backward force and be locked over a load at an
infinite number of extended positions within the operational length
of said telescoping coaxial bar, and is provided for with a means
to travel generally vertically up or down said single track, providing
said backwardly directed load restraining force at any point between
said upper end and said lower end of said upright frame
Patent Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to hand trucks and more
particularly to a two-wheeled hand truck with integral universal
clamping system for securing a load to the hand truck.
[0002] Conventional upright two wheeled hand trucks of various
designs are well known and have been in use in and around warehouse
spaces and cargo docks for many years. They are generally of simple
metal construction consisting of an upright frame extending vertically
from a load bearing platform or toe plate, a handle area at the
top of the upright frame and a set of wheels located near the bottom
of the upright frame located on either side of the toe plate. Although
hand trucks in their basic simple form are reasonably functional,
a universal and common problem involving the use of this type of
load transporting device has been the actual loading of cargo onto
the hand truck and restraining or securing to the hand truck the
many shapes and sizes of loads they are required to accommodate
in normal operation. The general procedure for loading a hand truck
requires the operator to slide a toe plate located at the base of
the upright frame under the load to be moved, then hold the cargo
back against the upright frame of the hand truck with one hand while
tilting or pivoting the frame back locating the load directly over
the wheels into the balanced position necessary for easy transport
It is often necessary when a particular load is too great in one
or more dimensions to secure the help of another person to provide
back pressure necessary for holding the load back in place against
the upright frame and on the toe plate of the hand truck while the
operator pivots or tilts the load back over the wheels into the
balanced position for transport. It is also necessary in most cases
for the operator to hold or stabilize the load with one hand to
insure that the load remains in place on the hand truck while simultaneously
keeping the load balanced over the wheels while pushing and steering
the hand truck to it's destination with the other hand.
[0003] In an effort to better contain loads and simplify the overall
handling and operation of hand trucks, a number of solutions to
the loading and load restraining problem have been introduced ranging
from the addition of specialized clamping or strapping mechanisms
to complete and radical reconfiguration of hand truck geometry.
The result has been the development of a multitude of different
types of specialized hand trucks designed specifically to contain
or handle a particular shape or geometric configuration of load
such as filing cabinets, gas bottles, barrels and drums, luggage
etc. Although these modifications have provided solutions to specific
problems, they often times take away from the hand trucks ability
to be used as a general-purpose device.
PRIOR ART
[0004] An example of a specialized configuration of hand truck
would be Turek and Schobergs U.S. Pat. No. 4893824 wherein a hand
truck for file cabinets is shown. Although the invention is equipped
with a restraining device for containing a file cabinet, it is limited
to use on loads that are roughly of the same square or rectangular
configuration and size as a file cabinet if the restraining device
is to be used. A load or cargo with considerably less depth than
that of a file cabinet that is held in place with this retaining
arm and clamping mechanism would require the unused or excess length
of the retaining arm be extended back through the upright frame
area where the operator is standing creating an obstruction for
the operator and resulting in difficult manipulation of the hand
truck. Additionally, the upright frame consists of an upper frame
and a lower frame that are telescopingly mated with the retaining
arm extending from the upper frame section. The result of this design
characteristic is that the retaining arm will only be functional
over the upper half of the hand truck making it difficult to restrain
flatter shaped loads or cargo with less height than a single drawer
file cabinet.
[0005] Mr. Morissette's U.S. Pat. No. 4,257,729, Hand Truck, is
another example of the more specialized approach; arranged with
a system for clamping the bead rim of a barrel or drum thus restraining
it to the hand truck. The mechanism outlined in this patent for
restraining the load would be of little use for loads that did not
have a bead rim or were not a similar cylindrical geometric configuration
as a barrel or drum.
[0006] The "Clamping device for use on hand truck" outlined
under Mr. Dunnings U.S. Pat. No. 4,492,505 is a load-clamping device
added to or mounted on the upright frame sections of a hand truck.
This approach is quite satisfactory for a number of load shapes
and sizes. It is however somewhat more complicated to use in that
the operator is required to select and mount a specific extension
bar into an extension housing for restraining a particular type
of load. The extension bar required would be dependant upon the
type or shape of the load to be secured to the hand truck. It is
important to note that the device of this invention secures the
load to the hand truck with downward force compressing the load
between the clamping mechanism and the toe plate of the hand truck.
Although this downward force seems to be suitable for restraining
certain geometric shapes of cargo for transport. In most cases it
lends little support in the actual loading process as a back force
which presses the load back against the upright frame of the hand
truck is usually required to keep the load on the toe plate and
in place against the upright frame of the hand truck when the upright
frame is tilted or pivoted back over the wheels to balance the load
for transport. In cases where the load extends outwardly from the
upright frame of the hand truck any appreciable distance beyond
the support of the toe plate, considerable downward clamping pressure
would be required to hold the load securely between the clamp and
toe plate to insure that the load remains against the upright frames
when the hand truck is tilted back to locate the load over the wheels
As mentioned earlier, this particular step in the loading process
generally requires that the load receive a backwards pressure holding
the load against the upright frame of the hand truck Excessive downward
pressure as would be required to keep the load in place would further
complicate the loading process if the cargo container is not substantially
rigid on all surfaces such as a common square or rectangular cardboard
shipping box, or if the load container has insufficient inside reinforcement.
In this case it may not be possible to apply the necessary downward
pressure required to keep the load back against the upright frame
without collapsing the container at the point where the clamping
pressure actually contacts the load.
SUMMARY
[0007] These are but a few of the examples that demonstrate the
need for a hand truck that is truly universal, in that it will accommodate
and restrain cylindrical and irregular shaped cargo as well as rectangular
shapes over the entire height of the hand truck frame, is easily
loaded by one person, has the capability to provide the load holding
or restraining forces back against the entire length of the upright
frame where it does the most good and can still be used in a conventional
manner if clamping or load restraint is not necessary. The present
invention offers forth a universal hand truck with an integral clamping
system designed to overcome the problems outlined above; comprising
an upright frame section formed by two parallel tubular sections
joined on the top end to form a handle, a toe plate which joins
the upright frame sections at the bottom and extends forward or
outward from the base of the upright frame providing for a load
bearing surface. A pair of wheels mounted one on either end of the
toe plate in such a way as to allow the upright frame to be pivoted
or tilted back to locate the load over the wheels or free stand
when not in use, supported by the two wheels and the toe plate.
A plurality of horizontal metal straps are provided as cross ties
extending between the two upright tubular sections adding strength
and rigidity to the upright frame of the hand truck. Cross ties
are formed in a slight concave arc to provide clearance for a vertical
slide track and substantially fixed horizontally between the toe
plate and handle of the two upright tubular sections that form the
upright frame with approximate equal spacing
[0008] A vertical slide tack for carrying a sliding piston or slide
lug and the load-clamping device is fixedly attached to each of
the cross ties at a point equal distance between and parallel to
the parallel tubular sections that form the upright frame. The vertical
slide track is fixedly attached to the top of the toe plate and
extends to the uppermost cross tie located a short distance below
the frame handle at the top of the hand truck. A front portion of
the tubular wall section of the vertical slide track is cut away
over the entire length of the vertical slide track to allow for
clearance of a coaxial clamping bar and clamping device which pivotally
attaches the slide lug to the coaxial clamping bar allowing the
load clamping device to be slid from the toe plate to the top of
the vertical slide track providing for the ability to clamp or restrain
a load over the entire vertical capacity of the upright frame of
the hand truck.
[0009] A load clamping device designed to provide for load restraint
by applying a clamping force back against the upright frame portion
of the hand truck is capable of securing cylindrical, rectangular
or irregular shaped loads that fit within an envelope defined by
the height of the hand truck and the length of a coaxial bar clamping
device. The clamping device consists of a telescoping coaxial clamping
bar and a clamp body provided for with load retaining fingers. The
coaxial bar which the clamp body is fitted to consists of a plurality
of sections, one fitting inside the other and allows for telescopically
extending the bar of the clamping device without overhang or obstruction
created by an unused portion of a clamping bar when containers or
loads that have minimal depth are secured to the hand truck. The
clamping body is arranged to slide over the outside tube of the
coaxial bar and is equipped with a means for rapidly locating and
locking the clamping body to any point along the length of the outside
tube of the coaxial bar The clamping body has dual flex mounted
clamping fingers located on either side of the clamping body and
extending downward and arranged to restrain flat, cylindrical and
irregular shaped containers or loads Clamping fingers are engaged
providing the necessary back directed force for securing or restraining
the load by a simple operator activated handle conveniently located
on the top of the clamping body.
[0010] When not in use, the telescoping coaxial clamp bar is collapsed,
the clamping body is slid to a stop at the outermost end of the
outside tube of the coaxial clamping bar. The clamping device is
pivoted to a vertical position on the slide lug and the slide lug
and clamping device is slid down into a vertical slide track to
a stored position freeing the hand truck for conventional uses that
do not require clamping or restraint of the load
[0011] It is the object of this invention to provide a hand truck
with an integral load-restraining device. It is also an object of
this invention to provide a load-restraining device that can accommodate
both cylindrical and rectangular shaped cargo. It is a further objective
of this invention to restrain the load by applying a backward force.
It is still a further objective to provide a clamping device that
collapsible and can be retained inside the hand truck when not in
use The foregoing objects including other advantages of the present
invention will become obvious to those skilled in the art to which
the invention pertains upon review of the following detailed description
and drawings in which,
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective view of the primary components of
the hand truck with an exploded view of the clamping components.
[0013] FIG. 2 is a top view of hand truck
[0014] FIG. 3 is a perspective detail view of slide lug attachment
to inside bar
[0015] FIG. 4 is a perspective dew view of the coaxial clamp bar
lock
[0016] FIG. 5 is an exploded view of the clamp components
[0017] FIG. 6 is a side view of clamp handle free sliding position
and engagement
[0018] FIG. 7 is a side view of clamp travel
[0019] FIG. 8 is a side view showing hand truck load clamping characteristics
and clamp stowage when not in use.
DETAILED DESCRIPTION
[0020] Referring now to FIG. 1 which shows an exploded view of
the hand truck 10 of the present invention including upright frame
11, a pair of wheels 12, a toe plate 13 a vertical slide track 14,
a slide lug 15, a telescoping coaxial clamping bar 16 comprising
an inside bar 17, an outside bar 18, a slide lug 15, and a geared
clamp 19.
[0021] Where in upright frame 11 of hand truck 10 is of a standard
height for hand trucks, (approximately 48 inches) and constructed
of a tubular metallic material. Upright frame 11 is comprised of
a flat metal toe plate 13, of hand truck 10. Toe plate 13 is fixedly
attached to the bottom of parallel tube sections 20 which extend
vertically from toe plate 13 and define the vertical load supporting
surface of hand truck 10. Parallel tube sections 20 are formed at
bend 30 and substantially joined at the top of upright frame 11
to form handle 21, which spans between parallel tube sections 20
and provides a means for the operator to manipulate hand truck 10.
A pair of ground engaging wheels 12 are rotatably fitted to either
end of axel 24. Wheels 12 and axel 24 are mounted to the lower back
of parallel tube sections 20 on triangular shaped brackets 26 which
extend rearward and are fixedly attached to rear of parallel tube
sections 20. Wheels 12 are mounted at an attitude where wheels 12
point of contact 27 with the ground is on the same horizontal plane
as the bottom surface of toe plate 13 when upright frame 11 is setting
vertically and unsupported.
[0022] Referring now to FIG. 1 and FIG. 2. A plurality of slightly
crescent shaped metal cross ties 22, evenly spaced one above the
other between toe plate 13 and handle 21 span between and are fixedly
attached to the back of parallel tube sections 20 and vertical slide
track 14 providing for increased rigidity of upright frame 11. Cross
ties 22 are crescent shaped to allow for clearance between vertical
slide track 14 and parallel tube sections 20 when loads are placed
on hand truck 10 and secured substantially with backward force against
parallel tube sections 20.
[0023] Vertical slide track 14 is constructed of a heavy wall tubular
member of approximately 21/2 inches in diameter with a portion of
the front face cut away 28 providing for clearance and pivotal attachment
of inside bar 17 of coaxial clamping mechanism 16 to slide lug 15.
(see FIG. 3). Vertical slide track 14 is fixedly attached at right
angles to each of the crossties 22 at points 25 approximately centered
and equidistance from parallel tube sections 20. The base end 29
of vertical slide track 14 is fixedly attached to the top surface
of Toe plate 13 and extends vertically and parallel to parallel
tube sections 20. Vertical slide track 14 is of a length approximately
equal to the longitudinal dimension of upright frame 11, as defined
by parallel tube sections 20,to a point where parallel tube sections
20 begin to form handle 21 at bend 30 of upright frame 11. Vertical
slide track 14 inside diameter is of a dimension which will allow
slide lug 15 to fit loosely inside vertical slide track 14 and slide
freely within the entire length of vertical slide track 14. Referring
again to FIG. 1 and slide lug 15 detail drawing FIG. 3 where slide
lug 15 comprises a metal or composition portion of bar stock approximately
1 7/8 inches in diameter and 2 1/2 inches long slot 31 in slide
lug 15 is approximately {fraction (5/16)}" wide and 1 inch
deep and provides for pivotal attachment of inside bar 17 of coaxial
clamping bar 16 to slide lug 15 with slide lug pin 32 which passes
through slide lug 15 pin hole 33, through pin hole 34 of inside
bar 17 and through slide lug pin hole 33 on the opposite side of
slide lug 15. It is important to note that slide lug pin holes 33
are arranged with a press fit clearance for slide lug pin 32 while
pin hole 34 of inside bar 17 is provided for with a loose fit clearance
between pin hole 34 and slide lug pin 32 thus allowing coaxial clamping
bar 16 to extend substantially up or vertical and axially aligned
with vertical slide track 14 to allow for stowage of coaxial clamping
bar 16 down and substantially inside vertical slide track 14 when
load restraining is not required. It should be noted that vertical
slide track 14 and slide lug 15 are cylindrical in cross section
allowing for coaxial clamp bar 16 and clamp 19 to be axially rotated
inside vertical slide track 14 as necessary to provide additional
clearance for clamp 19 when coaxial clamping bar 16 and clamp 19
are in the stowed position inside vertical slide track 14 (see FIG.
8D)
[0024] Referring again to FIG. 1A plurality of lug stop holes 37
are arranged over the length of vertical slide track 14 to provide
for stop pin 35 for the purpose of limiting the travel of slide
lug 15 and allowing for angular clamping of loads or clamping of
loads of irregular configuration when required (see ghost lines
in FIG. 8D). Lug stop holes 37 to be drilled through both walls
of vertical slide track 14 are sized to provide a slip fit for stop
pin 35 which limits the downward travel of slide lug 15 when stop
pin 35 is secured substantially through any of the plurality of
lug stop holes 37 in vertical slide track 14. A lanyard 36 of light
cord or wire is fixed on one end to a cross tie 22 or some other
portion of frame 11 and the other end to stop pin 35 preventing
stop pin 35 from being misplaced or lost when not inserted into
one of the lug stop 37 holes. Lanyard 36 to be of a length to allow
stop pin 35 to be placed into any of the plurality of lug stop holes
37 in vertical slide track 14.
[0025] Referring again to FIG. 1 where coaxial clamp bar 16 comprises
an inside bar 17, an outside bar 18 with clamp slide stop 38. Coaxial
clamp bar 16 is a telescoping arrangement which allows for varying
length of coaxial clamp bar 16 thus enabling clamping of a plurality
of load configurations without excessive outward overhang "O"
of the coaxial clamp bar 16 from the load (see FIG. 8C) thus contributing
to improved and less restricted maneuverability of hand truck 10
when working in confined areas. Inside bar 17 of coaxial clamp bar
16 measures approximately 1/4 inch thick by 1 inch wide is approximately
24 inches long and arranged for a sliding fit inside cavity 39 of
outside bar 18 with the other end pivotally attached to slide lug
15 as outlined previously. A plurality of detents 40 approximately
1/4" deep and located approximately 3 inches apart over the
length and on the upper or top side of inside bar 17 are provided
to mate with tang 41 on clamp bar lock 42 located on the end of
outside bar 18 (see FIG. 4) for the purpose of locking coaxial clamp
bar 16 to a particular operational length as might be desired by
the operator. Outside bar 18 of coaxial clamp bar 16 comprises a
cast or molded tubular component with a rectangular cross section
measuring approximately 1 1/2 inches high and 1 inch in width and
approximately 26 inches in length. Outside bar 18 to have a rectangular
hole through its length, forming cavity 39 with cavity 39 being
of a dimension offering proper slip fit clearance for inside bar
17 to be telescopingly received by outside bar 18. Outside bar 18
is provided for with geared surface 53 arranged in a configuration
that will provide for geared tooth 54 (see FIG. 4) profile and pitch
to properly mesh with tooth profile of gear 64 on handle 65 of clamp
19 (see FIG. 7) A screw threadedly attached to the slide surface
55 (see FIG. 6) of outside bar 18 on the end opposite face 52 of
outside bar 18 serves as slide stop 38 preventing clamp 19 from
being slid off the end of outside bar 18.
[0026] Referring now to FIG. 4 showing clamp bar lock 42 and geared
surface 53 of outside bar 18 which extends over entire length of
outside bar 18. Geared surface 53 adjacent to face 52 end of outside
bar 18 is provided for with relief 44, spring seat 49 and ramps
43 to facilitate operational attachment of clamp bar lock 42. Clamp
bar lock 42 to be a pressed, stamped or molded component approximately
3/4 inches wide and 2 1/4 inches in length and provides for maintaining
length adjustment of coaxial clamp bar 16 as might be required by
operator to contain various load configurations on hand truck 10.
Clamp bar lock 42 is pivotally mounted in relief 44 between ramps
43 located on face 52 end of outside bar 18, and secured with retaining
pin 45 which is press fit through pivot holes 50 in ramps 43 of
outside bar 18 and provided for with a slip fit through retainer
holes 46 on tabs 51 on clamp bar lock 42. A return spring 47 is
provided for applying upward force to bottom side of press tab 48
resulting in a pivotal motion of clamp bar lock 42 around retaining
pin 45 resulting in a downward or locking force to lock tang 41
holding lock tang 41 substantially in detent 40 as shown in FIG.
6. Return spring 47 seat 49 is a shallow indentation of about 0.050
inches in depth and is located in relief 44 of outside bar 18 seat
49 retains return spring 47 in relief 44 maintaining proper vertical
alignment of return spring 47 between bottom side of press tab 48
and relief seat 49. In operation, when press tab 48 is depressed,
clamp bar lock 42 pivots on retaining pin 45 causing locking tang
41 to be lifted from detent 40 of inside bar 17 allowing inside
bar 17 to slide freely within cavity 39 of outside bar 18 to facilitate
lengthening or shortening coaxial clamping bar 16 as required by
the operator for restraining a particular load configuration with
outside bar 18 in the approximate position required, the nearest
detent 40 on inside bar 17 is aligned with locking tang 41, press
tab 48 is released allowing locking tang 41 to seat into detent
40 of inside bar 17 locking the length of coaxial clamping bar 16
to the particular desired length
[0027] NOTE. In reference to the following clamp description. As
there are a number of gear types and profiles that could be utilized
while staying within the confines of this invention actual engineering
specifications for gear profile, design and tolerances of the clamp
are not outlined as part of this description.
[0028] Referring now to FIG. 5 showing a blowup view of gear clamp
19 whereby clamp 19 comprises a body 56 which is molded of a composition
material, cast from metal, or otherwise fabricated. Body 56 to be
approximately 6 1/4 inches high from base 57 to top of body ratchets
58, approximately 1 7/8 inches from front surface 59 to back surface
60 and 11/2 inches in width measured between outside surfaces of
cheeks 61. Each of the two cheeks 61 are provided for with a molded
in unidirectional tooth or ratchet profile 58 for mating with ratchet
teeth 86 on clamp lock 69. Ratchets 58 are configured to allow clamp
lock 69 of clamp 19 to be moved to the "E" or engaged
position (see FIG. 6) or "C", clamped position (see FIG.
7) and be automatically locked in position by downward pressure
of spring 85 of clamp lock 69 Two integral spacers 62 approximately
1/4 inch in diameter are molded or otherwise provided between inside
surfaces of cheeks 61 for the purpose of adding strength to body
56 and maintaining slip fit containment of outside bar 18 between
base 63 of body 56 and gear 64 located on the lower end of handle
65. Holes 66 are bored substantially through each cheek 61 of clamp
body 56 to provide for pivotal attachment of handle 65. Holes 66
to be approximately 3/8" diameter. Holes 66 location to be
the center point of radius "A" 67. (See FIG. 6) Radius
"A" 67 to be approximately 1 1/2 inches also defines the
radius of ratchets 58 located on cheeks 61 of body 56.
[0029] Handle 65 on clamp 19 is provided for applying the force
required to move clamp 19 along outside bar 18 back toward parallel
tube sections 20 of upright frame 11 and hand truck 10. Handle 65
of clamp 19 to be a metal or composition material approximately
7 inches long with core 68 cross section to be approximately 1/2
inch square in shape providing a dimension that will allow for a
sliding fit of clamp lock 69 when clamp lock 69 is slid over core
68 for reasons that will be explained later. Gear 64 to have a radius
of approximately 11/4 inches measured from the center of hole 71
on handle 65 with a pitch diameter and gear tooth profile arranged
mate with geared surface 53 when outside bar 18 is assembled into
clamp body 56. Gear 64 to be manufactured substantially integral
to handle 65. Hole 71 to be approximately 3/8 inches in diameter
and bored substantially through core sides 72 of core 68 on vertical
centerline 73 of core 68. Hole 71 provides for pivotal mounting
of handle 65 into clamp body 56 when assembled and retained with
pin bearing 74. Bushing collars 76 defmed by a raised portion of
material approximately {fraction (1/32)} inches high around the
circumference of hole 71 on either side of core 72 serves to decrease
friction between core sides 72 of handle 65 and inside surfaces
of cheeks 61 when handle 65 is assembled in body 56. Handle 65 is
assembled into body 56 by first orienting heel 77 of gear 64 to
face toward the back surface 60 of body 56. Handle 65 is then slid
straight down between inside of cheeks 61 and spacers 62 to a point
where hole 71 in handle 65 is directly aligned with cheek holes
66. Pin bearing 74, sized to slip fit into holes 66 in cheeks 61
and hole 71 in handle 65 to be inserted through first cheek hole
66, through hole 70 of handle 65 and on through second cheek hole
66 and seated to a point where head 78 of pin bearing 74 contacts
outer surface of cheek 61 on body 56. Snap ring 80 to be inserted
into pin bearing groove 79 securing handle 65 into clamp body 56.
[0030] Gear 64 on handle 65 is arranged with heel 77 providing
a relief for disengagement clearance between teeth on gear 64 and
geared surface 53 of outside bar 18 when handle 65 is in the "S"
or slide position (see FIG. 6) allowing clamp 19 to be slid freely
in either direction on outside bar 18.
[0031] Clamp lock 69 is comprised of cast metal or molded composition
material having a stem 92 that is rectangularly hollow to provide
for sliding over handle 65 with the exception of the top end being
at a point adjacent to pocket 83 providing for hole 82. Outside
surfaces of stem 92 to be of square cross section measuring approximately
7/8 inches on each side. Stem 92 to be provided for with a with
a griping surface 84 on one end for the purpose of lifting clamp
lock 69, compressing spring 85 and disengaging ratchet teeth 86
located on the lower end of clamp lock 69 from ratchets 58 of clamp
body 56. Disengagement of ratchet teeth 86 provides for unrestricted
movement of handle 65 in either direction. To assemble clamp lock
69 onto handle 65. Stem 92 of clamp lock 69 is slid over handle
65 to a point where stud 81 of handle 65 protrudes through hole
82 in pocket 83 of grip 4. Clamp lock 69 is held in the normal downward
locking position by spring 85 which is fitted over stud 81 on handle
65 between pocket 83 and underside of cap 87 during assembly. Cap
87 is fixedly attached to stud 81 on handle 65 with retaining screw
88. Retaining screw 88 passes through hole 89 in cap 87, through
spring 85 and is threadedly secured in threaded hole 90 to a point
where head of retaining screw 88 is seated in countersink 91 of
cap 87. Ratchet teeth 86 are formed into base end of stem 92 of
clamp lock 69 and are configured with a tooth geometry and radius
that will provide for mated engagement with ratchets 58 on cheeks
61 of clamp body 56. A light upward or lifting motion by the operator
applied to grip 84 on handle 65 disengages clamp lock 69 ratchet
teeth 86 from ratchets 58 allowing for free movement of handle 65
back to the "S" position (see FIG. 6) allowing clamp body
56 to move outwardly on outside bar 18 thus relieving pressure of
clamp 19 and fingers 94 on the load to enable unclamping of load.
Flex pad 93 with load restraining fingers 94 threadedly attached
to front surface 59 of clamp body 56 provide for direct contact
and containment of load between fingers 94 of clamp 19 and parallel
tube sections 20 of hand truck 10. Fingers 94 are arranged to accommodate
both flat surface loads and cylindrical shaped loads by allowing
clearance for the radius of cylindrical shaped loads between fingers
94. Flex pad 93 to be stamped, molded or otherwise constructed of
a material with substantial spring like characteristics in an inverted
"U" configuration approximately 10 inches wide measured
from outside to outside of fingers 94 and approximately 6 inches
high measured from top of spring back 95 to tip of fingers 94. Spring
back 95 of flex pad 93 to be of material approximately 1/8.sup.th
inch thick and 11/2 inches wide and formed to a concave configuration
with approximately 7/8 inches between front surface 96 at the point
where mounting holes 97 pass through spring back 95 to front faces
100 of fingers 94. This distance also defines the amount of flex
or "F" of spring back 95 and flex pad 93 as shown in FIG.
6. Fingers 94 of flex pad 93 to extend in a downward direction from
top of spring back 95 approximately 6 inches. Fingers 94 to be approximately
11/2 inches wide and bent back at point 99 where they converge with
ends of spring back 95 to an attitude where front faces 100 of fingers
94 are roughly parallel to front surface 59 of clamp body 56. Flex
pad 93 to be threadedly attached to face 59 of clamp body 56 with
four mounting screws 101 which pass through mounting holes 97 in
spring back 95 of flex pad 93 and seat into each of four threaded
holes 102 located on lower face 59 of clamp body 56.
[0032] Referring again to FIG.6 illustrating a side view of clamp
19 and coaxial clamping bar 16 for the purpose of operational explanation
wherein press tab 48 on clamp bar lock 42 is depressed allowing
operator to slide outside bar 18 either inwardly or outwardly on
inside bar 17 to the approximate desired length and allowing locking
tang 41 to seat into one of the plurality of detents 40 on inside
bar 17 when press tab 48 is released thus locking coaxial clamping
bar 16 at the approximate length required as determined by the operator.
With handle 65 in the "S" or slide position, as shown
with the ghost lines, heel 77 of gear 64 is rotated to a position
allowing for clearance between geared surface 53 of outside bar
18 and heel 77 of gear 64 of handle 65 allowing operator to freely
slide or position clamp 19 in either direction on outside bar 18
as required to provide for initial contact of fingers 94 of clamp
19 to contact load positioned on hand truck 10. Upon contact of
fingers 94 to the load., clamp handle 65 is rotated forward approximately
45 degrees to the "E" or engaged position where tooth
geometry of gear 64 engage the tooth geometry of geared surface
53 of outside bar 18.
[0033] Referring now to FIG.7 which shows the actual clamping process
wherein tooth geometry of gear 64 on handle 65 of clamp 19 is fully
engaged with tooth geometry of geared surface 53 of outside bar
18 resulting in clamp 19 travel "T" as required for secure
clamping when handle 65 is advanced approximately 70 degrees and
toward the clamped or "C" position. Fingers 94 of clamp
19 will be retained in position by the interlocking of ratchet teeth
86 on clamp lock 69 and ratchets 58 on cheeks 61 of body 56 until
operator lifts grip 84 on clamp lock 69 disengaging ratchet teeth
86 from ratchets 58 on cheeks 61 of body 56 thus allowing handle
65 to be moved back to the slide or "S" position, relieving
clamping pressure on fingers 94.
[0034] Referring now to FIG. 8 showing side views of the various
types of loads hand truck 10 can accommodate. Wherein FIG. 8-A depicts
the maximum size load "A" that can be clamped on hand
truck 10 where maximum horizontal length of the load "D"
is determined by the distance measured between fingers 94 of clamp
19 and parallel tube sections 20 of upright frame 11 of hand truck
10 and maximum load height "H" will be determined by the
measurement between the top surface of toe plate 13 on upright frame
11 and the uppermost point of vertical slide track 14, where slide
lug 15 and Coaxial clamping bar 16 can be positioned.
[0035] FIG. 8-B shows a flat load configuration "B" wherein
clamp 19, coaxial clamping bar 16 and slide lug 15 have been slid
down and positioned near the bottom of vertical slide track 14 for
the purpose of clamping and transporting a geometrically flat load
with hand truck 10.
[0036] FIG.8-C shows load "C" of a configuration that
is relatively high but with little depth. It is important to note
that with loads of this geometric configuration, coaxial clamp bar
16 provides for clamp 19 and outside bar 18 to be telescoped or
slid substantially over inside bar 17 resulting in a considerable
reduction in overhang "O" of the clamping system thus
allowing for easier and less restricted maneuvering of hand truck
10.
[0037] FIG. 8D shows the ability of coaxial clamp bar 16 and clamp
19 to be utilized at various angles as illustrated by positions
"W", "X", and "Y" as might be required
for clamping irregular shaped loads "I". Also shown in
FIG. 8. D, Stop pin 35 inserted into one of the plurality of lug
stop 37 holes which retains slide lug 15 at a selected height in
vertical slide track 14 as may be required by operator to aid in
clamping various irregular shaped loads on hand truck 10 Ghost lines
show coaxial clamp bar 16 in position "Z" angled vertically
on slide lug 15 and in position to stow the clamping system by sliding
coaxial clamp bar 16, and slide lug 15 down the inside of vertical
slide track 14 providing for conventional use of hand truck 10 which
may not require clamping of the load It can be seen that the forgoing
description of the preferred embodiment satisfies the objectives
of the invention in that the load-restraining device for the hand
truck is an integral part of the hand truck frame however can be
completely stowed within the frame allowing for conventional use
of the hand truck when required. The restraining unit also is capable
of clamping a wide variety of load configurations including cylindrical
shapes by applying a backward force against the upright frame and
has clamping capability over the entire height of the hand truck
frame. The preferred embodiment as described herein has been presented
for the purposes of illustration and description and is not intended
to be exhaustive or to limit the invention to the precise form disclosed.
Modifications and variations to the hand truck frame as well as
the clamping system as outlined herein are possible in light of
the above teaching. It is intended that the scope of the invention
not be limited by this detailed description but rather by the claims
appended hereto. |