|
Patent Abstract
A novel two wheel-hand truck for easy, semi-automatic, loading and
unloading, is equipped with a means, which is installed in the platform
of the hand-truck, including but not limited to, double layers,
upper and lower layer, of staggered rollers in the platform, a synthetic
rubber belt optionally surrounding the upper layer rollers to fill
the clearances, and two wheels. The rollers are constructed of cast
iron having outer diameter of 3 to 30 mm. Diameter of all the rollers
of the upper layer and the lower layer may be the same. More than
one row of the double layers may be installed in row in a platform.
The front edge of the platform is tapered for easy access of the
bottom of the luggage to be loaded.
Patent Claims
What is claimed is:
1. A semi-automatic loading/unloading two wheel-hand truck is comprised
of two wheels, rail arms, crossing bars, handles, toe platform having
tapered front nose and void in the middle, and plurality of double
layer staggered rollers, the upper layer rollers and lower layer
rollers consist a triangle with the three centers of neighboring
three rollers contacting directly each other on the other layer
meanwhile avoiding contact with other rollers on the same layer,
which are made of cast iron rods having outer diameter of 3 to 30
mm and engaged to the platform by dust cover equipped bearings,
in the platform.
2. The outer diameter of the rollers, in claim 1, is the same as
the inner diameter.
3. The outer surface of the rollers of the upper layer, in claim
1, is coated with a synthetic rubber.
4. The upper layer's rollers, in claim 1, are surrounded with a
synthetic rubber belt.
Patent Description
[0001] This invention relates to a semi-automatic two-wheel hand
truck enabling easy loadings and unloading of a luggage.
FIELD OF THE INVENTION
[0002] A novel two-wheel hand truck has double layers, staggered
rollers in the platform for easy loading and unloading of luggage.
DESCRIPTION OF THE PRIOR ARTS
[0003] U.S. Pat. No. 2,578,887 to Jackson et. al, U.S. Pat. No.
2,766,543 to Beck, U.S. Pat. No. 2,360,799 to Slingsby, and U.S.
Pat. No. 1,710,893 to Phillips illustrate a two wheel hand trucks,
which have various shape of pushing means for unloading luggage
on the cart. The user operates the pushing means by hands. U.S.
Pat. No. 2,838,193 to Statton, U.S. Pat. No. 2,476,202 to Lozon,
Sr., and U.S. Pat. No. 528,443 to Randall illustrate hand trucks,
which have luggage pushing means operated by a user's foot. Purpose
of those pushing means is to accomplish an easy unloading.
[0004] None of prior art utilizes rollers for dolly or hand trucks.
[0005] U.S. Pat. No. 6,471,045 to Harden illustrates a roller and
belt conveyor system with several roller assemblies supporting a
plurality of conveyor belt sections for conveying articles. U.S.
Pat. No. 5,152,522 to Yamashita illustrates a roller assembly, on
one of a pair of shafts are axially arranged in staggered positions
with those on the other shaft.
[0006] U.S. Pat. No. 4,546,631 to Eisinger, U.S. Pat. No. 4,287,743
to Hantschk, U.S. Pat. No. 2,769,478 to Schane, U.S. Pat. No. 2,749,962
to Kitselma, illustrate roller mechanism and method for forming
helical structures from a feed wire or rod. Pluralities of rollers
are staggered.
[0007] U.S. Pat. No. 4,214,379 to Hope, et al. illustrates a gear
driven transport rollers arranged in a staggered pattern. It carries
the film through the rack along a sinuous path. All of the prior
art rollers illustrate staggered roller for transporting a thin
material between the rollers.
[0008] None of the prior art illustrates a simple, easy and novel
method of loading/unloading and transporting mechanism of this invention
utilizing an assembly of staggered rollers.
SUMMARY OF THE INVENTION
[0009] It is the purpose of this invention to provide a novel easy,
safe and semi-automatic loading/unloading hand truck. A novel two
wheel-hand truck for that purpose is equipped with a means, which
is installed in the platform of the hand-truck, including but not
limited to, double layers, upper and lower layers, of staggered
rollers in the platform, a synthetic rubber belt optionally surrounding
the upper layer rollers, and two wheels. The rollers are constructed
of cast iron having outer diameter of 3 to 30 mm. Surface of the
rollers may be coated with synthetic rubber. Diameter of all the
rollers of upper layer and lower layer may be the same. More than
one row of the double layers may be installed in a row in a platform.
The front edge of the platform is tapered for easy access of the
bottom of the luggage to be loaded.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of the two-wheel hand truck
of this invention.
[0011] FIG. 2 is a cross sectional side view of the staggered rollers
in the platform of the hand truck of this invention along the line
`A-A` in the FIG. 1.
[0012] FIG. 2-1 is a cross sectional side view of the staggered
rollers in the platform of the hand truck of this invention along
the line `A-A` in the FIG. 1 when a synthetic rubber belt is optionally
engaged.
[0013] FIG. 3 is a schematic drawing showing the relative movement
of rollers, luggage, and hand truck of this invention when loading
a luggage.
[0014] FIG. 4 is a schematic drawing showing how to use the hand
truck to move to another place with luggage.
[0015] FIG. 5 is a schematic drawing showing the relative movement
of rollers, luggage, and hand truck of this invention when unloading
a luggage.
[0016] FIG. 6. is an exploded schematic drawing showing the connection
of the rollers to the dust cover equipped bearings in the side wall
of the platform of the hand truck of this invention.
[0017] FIG. 7. is a partial perspective view of a conventional
dust cover equipped bearings installed to the hand truck of this
invention.
[0018] FIG. 8 is a side view of a roller showing the triangular
shaft for engaging to the bearing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] FIG. 1 is a perspective view of the two-wheel hand truck
of this invention. The hand truck has two wheels (1), rail arms
(2), crossing bars (3), handles (4) and toe platform (5), and plurality
of rollers (6).
[0020] FIG. 2 is a cross sectional side view of the staggered rollers
in the platform of the hand truck of this invention along the line
`A-A` in the FIG. 1. The upper layer rollers (6u) and lower layer
rollers (6d) are staggered with respect to each other in a way of
consisting a triangle (7) by the three centers (8) of neighboring
three rollers. The outer face (9) of each roller contacts directly
to the neighboring roller's outer surface (9) of the opposite layer.
Rollers on the same layer do not contact each other. The upper surface
of the upper layer's roller (6u) emerges above the upper surface
(10) of the platform and the lower surface of the lower surface
of the lower layer's roller (6d) emerges below the lower surface
(11) of the platform. The outer surface (9) of the upper layer's
rollers may be coated with a synthetic rubber. A synthetic rubber
belt (9-1) is engaged optionally surrounding the upper layer's rollers
(6u) as shown in FIG. 2-1.
[0021] FIG. 3 is a schematic drawing showing the relative movement
of rollers (6), luggage (13), and hand truck (12) of this invention
when loading a luggage. When loading a luggage (13), a user put
the hand truck (12) of this invention in front of the luggage (13)
and pushes the hand truck (12) forward to the direction of the luggage
(13). The tapered nose (14) of the platform, firstly, inroad into
the under side of the luggage (13). For further pushing of the luggage,
the bottom of the luggage (15) is mounted on the platform (5) and
contacts the upper surfaces of the upper layer's rollers (6u), which
are exposed above the upper surface (10) of the platform (5). As
shown in FIG. 3, when a user pushes the hand truck forward, the
lower layer's rollers (6d), contacting the ground (16), turns clockwise
(17). It is clear that at the opposite side the lower layer rollers
look (6d) turning counter-clockwise. At the same time, the upper
layer's rollers (6u) turns counter-clockwise (18), induced by the
rotation of the lower layer's rollers (6d). The upper layer's rollers
movement drags the bottom of the luggage (15) into the direction
of the rail arm (2). Pushing of the hand truck (12) more forward
moves the luggage (13) from the front tip (14) of the platform to
the inner side of the hand truck. For moving from one place to another
place, the hand truck should be leaned backward as shown in FIG.
4.
[0022] Likewise, an unloading the luggage (13) is much easier.
FIG. 5 is a schematic drawing showing the relative movement of rollers,
luggage, and hand truck of this invention when unloading a luggage.
Putting the hand truck (12) in an up-right position and pulling
the truck backward is illustrated in FIG. 5. The lower layer's rollers
(6d) turn counter-clockwise (19) and this time turns the upper layer's
rollers (6u) clockwise (20). The upper layer's rollers (6u) drags
the luggage (13) to the front side of the hand truck (12) and finally
unloads it.
[0023] FIG. 6. is an exploded schematic drawing showing the connection
of the rollers (6u and 6d) to the dust cover equipped bearings (21)
in the side wall (22) of the platform of the hand truck of this
invention. The bearings (21) are mounted in the side wall (22) of
the platform. Their relative positions are decided by the relative
position of the rollers. As indicated as (23) in FIG. 6 and shown
in FIG. 2, the upper layer rollers (6u) and lower layer rollers
(6d) are staggered with each other in a way of constituting a triangle
(7) by the three centers (8) of neighboring three rollers. The upper
surface of the upper layer's roller (6u) emerges above the upper
surface (10) of the platform and the lower surface of the lower
surface of the lower layer's roller (6d) emerges below the lower
surface (11) of the platform. But the bearings (21) are installed
within the limit of the boundary of the side wall (22) of the platform
(5). The centers of the bearings (21) match the rotational centers
of the rollers (6u and 6d). The rollers (6u and 6d) are engaged
to the bearings (21) by the triangular shaft (24).
[0024] FIG. 7. is a partial perspective drawing of a conventional
dust cover equipped bearing (21), with triangular window (25) for
receiving a triangular shaft (24) of the rollers (6), installed
to the hand truck of this invention. FIG. 8 is a side view of a
roller showing the triangular shaft (24) for engaging into the bearings
(21). |