Note: Descriptions are shown in the official language in which they were submitted.
"LINK FOR A LINKED ROW TYPE CONVEYOR"
BACKGROUND OF THE INVENTION
This invention relates to a link for use in a
linked rod type conveyor of the type which may be used in
a potato harvester or similar machine.
Generally such linked rod conveyors include a
plurality of links each of which has a transverse
straight portion extending fully across the width of the
conveyor and defining the surface of the conveyor. A
pair of loop members are arranged at respective ends of
the straight portions so as to extend forwardly therefrom
to engage the next adjacent link particularly at the ends
of the straight portion thereof. Thus forward motion is
transmitted from one link to the next through the loop
members with the forward extent of the loop members
defining the spacing between each straight portion and
the next adjacent straight portion.
Generally conveyors of this type wrap around
rollers or sprockets at a forward and rearward end of the
conveyor run so as to form a continuous chain of the
links. In one example of a machine of this type, a blade
engages the ground ahead of a forward roller of the con-
voyeur so as to lift broken earth from the ground onto the
lo
top of the conveyor run so the earth is carried rearward-
lye on the conveyor run while acting to separate potatoes
or the like from the earth.
It will be appreciated that, as the links move
around the front roller and the drive sprocket of the
conveyor run, it is necessary for rotation to occur
between the loop member of one link and the straight
portion of the next adjacent link. This rotation occurs
only over a limited angular extent of the next Addison
rod and occurs only at the front and rear ends of the
conveyor run; however it occurs under highly stressed and
contaminated conditions. In particular the soil
particles can enter into the spaces between the loop
member and the rod and can thus act as a highly effective
abrasive. No lubrication is of course possible in this
area.
This vigorous working of the loop member on the
next adjacent link thus causes rapid and highly damaging
wear. In particularly harsh conditions, the rod conveyor
which acts upon the ground can last only approximately
one wee of operating time before it is necessary to
replace the links.
Normally each link is formed solely from a rod
of approximately 1/2 inch diameter which is bent to form
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the transverse straight portion and the forwardly extend-
in loop members. One example of a device of this type
is shown in United States patent no: 2,555,~92 (Hatch).
In this arrangement the inventor attempts to reduce the
wear by increasing the length of contact between the loop
member and the next adjacent link. This is obtained by
forming a rearwardLy curved portion at the next adjacent
link so that the loop member and the rearward curved
portion are more closely interlined around a greater
angular extent thereof. However this device has not
proved satisfactory and for more than 40 years the simple
rod link conveyor has been available and farmers have
been obliged to put up with the unsatisfactory wear
characteristics.
SUMMARY OF THE INVENTION
It is one object of the present invention,
therefore, to provide an improved link for a linked rod
conveyor of this general type which significantly
increases the life of the links before wear causes their
replacement.
According to the invention, therefore, there is
provided a link for use in a linked rod conveyor comprise
in a single rod bent to form a generally straight
portion for extending transversely of the conveyor and a
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pair of loop members each at a respective end of the
straight portion and arranged to extend forwardly there-
from to engage around a next adjacent link to transmit
forward movement therefrom to the link and two additional
portions attached to the rod each at a respective loop
member, extending to one side thereof and defining a
curved bearing surface for engaging around the next
adjacent link.
Preferably the additional portion attached to
the link at the loop member is formed from an initially
flat strip of steel which is bent to define the curved
bearing surface and is welded to an inner side of the
loop member to form a bearing surface contiguous there-
with. Preferably the angularly spaced edges of the bear-
in surface taper inwardly as the distance from the loop
member increases so as to reduce the angular extent of
the bearing surface as the distance increases. This
enables the next adjacent rod to sit in the recesses of
the sprocket wheel and to engage the teeth of the
sprocket wheel without the additional portion interfering
with the proper engagement. Preferably the sides of the
additional portion taper from an angular extent greater
than ]80 to an angular extent lets than 90.
With the foregoing in view, and other ad van-
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taxes as will become apparent to those skilled in the art
to which this invention relates as this specification
proceeds, the invention is herein described by reference
to the accompanying drawings forming a part hereof, which
includes a description of the best mode known to the
applicant and of the preferred typical embodiment of the
principles of the present invention, in which:
DESCRIPTION OF THE DRAWINGS
Figure 1 is side elevation Al view of the front
conveyor chain of a potato harvester omitting for convent
fence of illustration the frame structure.
Figure 2 is an isometric view showing the
interconnection between one link and the next adjacent
link at one end of the links.
Figure 3 is a plan view of an additional
portion of one of the links prior to bending to define
the curved bearing surface.
Figure 4 is a plan view of the conveyor of
Figure 1 showing a part only thereof adjacent the
sprocket wheel.
Figure 5 is a side elevation Al view of one link
showing the addition portion attached thereto.
In the drawings like characters of reference
indicate corresponding parts in the different figures.
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DETAILED DESCRIPTION
Referring firstly to Figure 1 there is shown
the general system of a potato harvester of the type with
which the present invention is particularly concerned.
Specifically there is provided a front bar 10 which is
an elongate rod of the order of one inch in diameter
which engages the ground and is driven forwardly into the
ground by the. supporting frame structure (not shown).
Immediately rearwardly of the rod 10 is provided a guide
plate 11 which carries the broken and cut soil from the
rod 10 generally in an inclined upwardly direction toward
the conveyor chain indicated at 12. The conveyor chain
is formed from a plurality ox rod type links each of
which is of the construction shown in Figures 2 through 5
and includes a straight portion 13 which extends trays-
tersely across the conveyor from one side to the other
and a forwardly extending loop portion 14 which wraps
around the next adjacent forward link so as to transmit
force from the forward link to the rearward lynx and thus
throughout the whole chain.
The complete continuous chain wraps around a
front roller AYE defined by two roller parts which are
spaced apart so they engage effectively only the loop
members leaving the central area of the conveyor defined
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by the straight portions 13 of the rods for grasping and
carrying the soil and harvested potatoes. At a rear end
of the conveyor is provided a drive sprocket AYE which
includes teeth 17B and recesses 17C for engaging around
the outermost ends of the straight portion as shown best
in Figure 4 for generating the forward motion of the
links of the chain.
In operation the soil cut and lifted by the rod
is transported over the upper run of the conveyor
chain so that soil breaking away from the potatoes falls
through the spaces between the rods while the spacing is
chosen to collect and carry potatoes of a reasonable
size.
Rearwardly of the conveyor is provided a pour-
amity of further conveyors which further separate soil
and in addition which are arranged with larger spacing so
as to carry the foliage from the potato plant away from
the crop of potatoes.
Turning in more detail to the links individual-
lye each link includes the straight portion 13 which monocled a slight upward inclination adjacent the outer-
most end so that the central straight portion lies in a
slightly lower plane than the inner end of the loop
member 14.
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From the outermost end of the straight portion
13 adjacent the root of the loop member, the loop member
includes an inwardly and forwardly extending portion I
a bight portion I which lies substantially in a vertical
plane and a rearwardly, downwardly and slightly inwardly
extending tail portion 17~
The construction described to this point is of
a conventional nature and has operated in the manner
described for at least 40 years.
The present invention provides the improvement
of an additional bearing portion generally indicated at
18. The additional bearing portion is shown as a flat
blank in Figure 3 indicated at 19. It will be noted that
an innermost edge 20 of the portion is of a treater
length than an outermost edge 21 so as to define tapering
sides 22 and 23. In manufacture, the blank 19 is formed
into a curve so that the inner surface thereof has a
radius of curvature substantially equal to or slightly
greater than the radius of curvature of the rod. This
curvature it substantially equal to the curvature of the
bight portion 16 so that the bight and the additional
portion 18 wrap closely around the straight portion of
the next adjacent link.
In Figure 4 the position of the links in
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engagement with a sprocket wheel AYE is shown. Generally
the sprocket wheels are spaced so that they run on the
links just inside the innermost extent of the additional
portions 18. However in operation it it quite common for
the conveyor chain to slightly wander transversely so the
additional portions 18 on one side of the links overlap
the adjacent sprocket wheel. In this case, as shown in
Figure 4, the taper of the edges 22 and 23 is arranged Jo
that the angular extent thereof at the edge 21 remote
from the respective bight portion is less than 90 so
that the additional portion can lie in a recess 18 of the
sprocket wheel 16 effectively without engaging the sides
of the teeth 17. The extent of the edge 20 of the add-
tonal portion is such that when it wraps around the rod
it extends over an arc slightly greater than 180~ and
defines a loose fit bearing surface around therefore
approximately one half of the straight portion of the
next adjacent rod.
The link of the invention is therefore formed
by a single rod which is bent as in the conventional type
link to form the straight portion and the loop member
extending forwardly therefrom and is modified by the
addition of the particularly shaped additional bearing
surface which extends outwardly to one side of the loop
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member.
Since various modifications can be made in my
invention as hereinabove described, and many apparently
widely different embodiments of same made within the
spirit and scope of the claims without departing from
such spirit and scope, it is intended that all matter
contained in the accompanying specification shall be
interpreted as illustrative only and not in a limiting
sense.
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