Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates generally to flight
conveyors and more particularly to improved drag link chains
for moving bulk material along a trough or other conveying
surface. The chains are constructed from links having a
closed end and an open end.
Links are made by welding, casting or otherwise
fixedly securing one piece barrels to first ends of sidecars
forming the closed end of a link. A number of links as desired
or required are joined together in tandem fashion to form a
chain by inserting a pin through a barrel of a closed end
of a first link and press fitting the outer ends of the pin
in a second end of each sidecar forming the open end portion
of the link. The leading side of each link barrel has a
flat, vertical surface to act as a pusher of the material being
conveyed.
Drag or offset link chains are operated normally
with the "open end" of the link facing forward. When a chain
is run in this manner, wear is concentrated on both the outer
diameter of the pin and the inner diameter of the barrel.
If the direction of travel is reversed, and the closed end"
of the links is facing forwardly, there is caused a consider-
able, undesired amount of concentrated wear resulting from
joint articulation between the outer barrel surface of the
link and a sprocket tooth.
In the past, a number of attempts have been made to
solve the problems encountered and solved by the present
invention. In United States Patent No 581,689, which
issued to JOY. Brown on May 4, 1897 there is shown a chain
construction using links wherein apertures are formed that
include V-shaped projections for bearing against transverse
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pins having centrally enlarged portions concave on one side
and convex on the other side. Friction between pin and link
is presumably minimized by round surface contact of the pin
with knife end contact of the projection in the aperture of
a link.
US. Patent No. 1,951,764, which issued to FLY.
Morse on March 20, 1934 shows a drive chain having links
joined together by pins having an arcuate surface on one side
and a flat keying surface on the other side. The links
rotate about the round side of the ponytail but are restrained
from turning by the flat side.
US. Patent No. 2,956,442, which issued to CUB.
Krekeler on October 18, 1960 shows a mining chain having
block links joined together by ponytails having a flat side
and an arcuate side and further having a cut away, eccentric
inner arcuate surface and round outer end portions for fitting
in apertures or perforations of the links.
US. Patent No. 3,585,872, which issued to GAS.
McDowell on June 22, 1971 is similar to the Krekeler US.
Patent No. 2,956,442 and shows a cutter chain having cutter
bit links and connector links joined together by ponytails
shaped to provide outer shoulder portions with one side
arcuate and the other side flat, an intermediate, cut away
portion with an arcuate surface between the flat sided portions
of the shoulders.
US. Patent No. 3,880,014, which issued to WOW.
Kendall on April 29, 1975 shows a drive chain made from
link members serially connected in overlapping relationship
so that their connected portions form arcuate rocking bearing
surfaces there between.
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US. Patent No. 4,036,072, which issued to JO McKeon
on July 19, 1977 shows a steel roller chain wherein bushings,
with rollers free to rotate thereabout, are welded between
side bars to form a compact structure with no outward pro-
sections beyond the outside faces of the side bars, thus
reducing overall chain width.
Accordingly, it is a primary object of the present
invention to provide an improved construction of chain links
by seating the links on teeth of a sprocket so as to avoid
relative movement there between and thereby minimize wear that
usually occurs when teeth of a sprocket drive against the
barrel of a drag chain link. This object is achieved by
welding, casting or otherwise fixedly securing a one piece
barrel between first ends of a pair of sidecars to form a
lo closed end portion of a link, wherein the barrel has a flat
vertical surface facing inwardly of the link toward second
ends of the sidecars, the second ends of the sidecars forming
an open end portion of the link. A plurality of links are
joined together by inserting a pin through a barrel of a
closed end portion of a link and press fitting the outer
ends of the pin into ends of sidecars forming an open end
portion of a second link that has been positioned to overlap
the sidecars of the first link and have apertures aligned
coincidentally with the bore of the barrel of the first link.
A further advantage of the improved chain link
construction is to provide a closed end portion of a link
having disposed thereat a flat sided barrel facing toward an
open end portion of the link and a rounded portion of the
barrel seats on the root diameter of a sprocket tooth
restrained from rotation there between, thereby reducing
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wear on both the outer circumferential surface of the barrel
and teeth of the sprocket.
A further object of the present invention is to
provide an improved drag link construction wherein closed
end portions of links forming an endless conveyor chain
at times contact teeth of sprockets without relative
rotation there between.
An additional advantage of the present invention is
to provide an improved drag link construction wherein a
barrel is secured at a closed end portion thereof and the
barrel has a flat side portion oriented towards an open end
of the link, a plurality of links being joined together by
pins to form an endless conveyor chain wherein at times the
barrels seat on teeth of sprockets with no relative rotation
there between.
An improved drag link in accordance with the present
invention comprises a plurality of sidecars having portions
thereof angled obliquely inwardly to form first end portions
thereof, a barrel having formed there through a bore being
disposed substantially normal to and between the first end
portions of the sidecars and fixedly secured thereat to
form a closed end portion of a first link, the barrel having
a flat vertical surface formed thereon facing toward second
end portions of the sidecars forming an open end portion of
the first link, the flat vertical surface of the barrel
forming a plane normal to a longitudinal axis of the link,
the barrel of the link having a rounded exterior surface
formed to cooperate with and seat on a tooth of a sprocket
for driven engagement therewith, a pin for at times being
inserted through the bore of a barrel of a second link
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placed in juxtaposition between the second end portions of
the sidecars of the first link to fixedly secure the barrel
of the second link to the second end portion of the first
link sidecars, the barrel of each link being adaptable at
times to seat on teeth of the sprocket during driven
engagement therewith so that no relative rotation occurs
there between.
The foregoing and other characteristics, object,
features and advantages of the present invention will become
more apparent upon consideration of the following detailed
description, having reference to the accompanying figures of
the drawings, wherein:
Figure 1 is a perspective view of a pair of chain
links typical of offset drag chains which reflect the state
of the present art;
Figure 2 is a plan view of an assembly of links
showing the relationship of the component parts to each other
and to the driving sprocket;
Figure 3 is a sectional view taken along line 3-3
of Fig. 2 showing the point of articulation with the sprocket
and the links immediately preceding and following that point;
Figure 4 is a perspective view of a pair of chain
links fabricated and assembled in accordance with the present
invention;
Figure 5 is a top view of an assembly of links
similar to Fig. 2 and
Figure 6 is a sectional view taken along line 6-6
of Fig. 5 particularly pointing out the point of articulation
between the pin and the barrel bore so as to the manner in
which the present invention distinguishes over the structure
of Figs. 1-3.
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Referring now to the figures of the drawing, there
is illustrated a drag chain link generally identified by the
reference numeral 10. The link 10 comprises a pair of
sidecars 12 formed generally in the shape of a solid rectangle
or parallelopiped, each sidecar having a portion nearer one
of its ends being bent inwardly or obliquely for a predetermined
length and then being bent forwardly to assume a straight
position parallel to its other end. The two sidecars 12 are
placed parallel to and apart from each other having their
first ends 14 spaced apart a distance less than that separating
the sidecars at their second ends 16. Each sidecar 12 has
apertures 18 formed at its outer ends. The apertures 18
are disposed oppositely from each other along a longitudinal
coincident axis 20 when the sidecars are aligned in parallel
relationship.
A bushing or barrel 22 is disposed between the
sidecars 12 generally perpendicular or normal thereto at the
first ends 14 of the sidecars and is securely affixed thereat
as by welding, casting or the like. The barrel 22 has a
bore 24 formed there through. The bore 24 ox the barrel 22
has a longitudinal axis that is coincidental with the
longitudinal axis 20 of the apertures lo when the barrel
is securely disposed between the sidecars 12.
The barrel 22 when secured to the first ends of the
sidecars 12 cooperates therewith to form a narrow closed
end of the link 10, the closed end of the link being identified
generally by reference numeral 26. The second ends I of
the sidecars 12 cooperate to form a wider portion of the link
that comprises an open end thereof, the open end of the link
identified generally by reference number 28.
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1~3~L073
The barrel it formed to have a flat generally vertical
surface 30 on a first or a front side 32 and a round surface
34 on a second or back side 36. In Figs. 1-3, it will be
noted that the barrel is secured between the sidecars having
its first or front flat vertical surface 30 facing out-
warmly from the closed end and away from the open end of
the link, forwardly in the direction of travel of the chain
as represented by an arrow 38 in Figs. 2-3. In Figs. a-6/
it will be noted the barrel 22 is secured between the sidecars
12 having its first or front flat vertical surface 30 facing
inwardly toward the open end 28 of the link 10, but still
facing forwardly in the direction of travel of the chain as
represented by an arrow 40 in Figs. 5-6. The purpose of this
significant difference in orientation will be hereinafter
explained in greater detail.
A pin 42 is effective to connect together a plurality
of links so as to form an articulated joint there between.
A plurality of the pins 42 are utilized to join a series of
links in tandem relationship to form an endless chain. The
open end 28 of a first link is positioned over and about a
closed end 26 of a second link so that the apertures of the
sidecars of the first link are aligned with the bore of the
barrel secured between the sidecars of the second link. The
pin 42 is fitted through the bore of the barrel and has its
outer ends press fitted or otherwise secured into the apertures
18 of the sidecars 12 comprising the open end portion 28 of
the first link. The pin in its press fitted or otherwise
secured position is locked against rotation. Additional links
are joined in succession in similar fashion to form an endless
chain of a predetermined or desired length.
073
In prior art construction, as represented in Figs.
1-3, the chain has its links oriented with their closed ends
forward along with the flat side of each barrel facing for-
warmly so asset push material along a trough or other conveying
surface. As the sprocket rotates clockwise, a tooth 44 of a
sprocket 46 engages with and drives against a barrel, disposed
at a closed end 26 of a first link 48. Continued clockwise
rotation of the sprocket causes the link to fully seat on the
sprocket so that the rounded portion 34 of the carrel 22
of the fink 48 is seated against tooth 44 of the sprocket and
the open end 28 of link 48 forms a join of articulation with
the closed end 26 of a following link 50. As the sprocket
continues to rotate clockwise, the link 50 having its barrel
22 in seated engagement with a tooth 52 of the sprocket 46
forms a joint of articulation or slid able friction therewith
and results in maximum wear on both the barrel and the tooth of
the sprocket. As a barrel of each following or successive link
moves into engagement with a sprocket tooth, there is formed
an articulated joint between a barrel and a sprocket tooth
resulting in great stress and excessive wear there between.
As a consequence, there is caused premature wear of both the
barrel of a link and the tooth of a sprocket that ultimately
causes failure of one or both of these conveyor components.
Referring now to the link 10 shown in Fig. 4 of the
present invention, it will be readily observed that a sign-
ficant structural difference is depicted in that the flat
front vertical surface 30 of the barrel 22 faces in a forward
direction toward the open end 28 of the link 10. Drag type
chains as herein before discussed are constructed having the
flat front surface of the barrel facing in the direction of
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travel of the chain so that the chain can push material
efficiently along a trough or other conveying surface.
With reference specifically to Figs. 5-6, it will be
noted that the chain has its links disposed so that their
open ends 28 are oriented forwardly in the direction of travel
narrow 40) and the flat side 30 of each barrel 22 faces
forwardly for pushing material along a conveying surface. As
the sprocket 46 rotates clockwise, the tooth 44 of the
sprocket 46 engages with and drives against the rounded side
34 of a barrel 22 disposed at a closed end 26 of a preceding
link of the chain. As the sprocket continues to rotate, the
barrel 22 of a link 54 becomes fully seated against the tooth
52 of the sprocket 46.
Further clockwise rotation of the sprocket causes a
pin 42 of a following link 56 fitted within the bore 24
of the barrel 22 of the link 54 to form a joint of articulation
between the outer diameter of the pin and the inner diameter
of the bore 24 of the barrel 22. In this mode, the barrel is
stationary relative to the sprocket 46 while the pin 42 disposed
at the open end of link 56 rotates within and against the bore
24 of the barrel 22 of link 54. It will be noted that the
articulated joint formed between the barrel bore and pin outer
diameter occurs by contact between the rearward curved portion
of the barrel bore and a portion of the circumferential surface
of the pin. Rotation between the inner diameter of the bore
and the outer diameter of the pin permits the rounded outer
portion of the barrel to be fully seated on the root diameter
at the base of the sprocket tooth and thereby avoids forming
an articulated point between the barrel and a sprocket tooth.
The barrel maintains a fully seated non-rotative relationship
73
with the sprocket tooth throughout rotation ox the sprocket
and until the barrel is disengaged from the sprocket tooth.
Thus, there is no relative motion or slid able friction
between a barrel and a sprocket tooth. As a result, no stresses
of magnitude are created, nor is excessive wear caused on
a barrel of a link or a sprocket tooth that ultimately could
contribute to the failure of one or both of these conveyor
components.
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