Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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l This invention relates -to flights for conveyor chains
and more particularly to polymeric flights attachable to chains
for conveying loose material.
Conveyor chains employing a continuous chain moving in
the direction of its length are used widely for the conveying of
material. Flights extend from the sides of the chain in
directions transverse to the direction of movement of the chain
for applying the conveying force of the chain. The flights can
be of various types and shapes for different conveying
purposes. Examples include pusher flight attachments, blade
flights for chain -that is used in digging, and flat top flights
for carrying articles. A common type of flight used for
conveying loose material has arms extending from each side of a
central chain which is moving through a chute such that the
flights push the material as they move along the floor of the
chute.
Before the advent of polymeric materials usable in
conveyor chain applications, ~he flights were usually of steel
and were either welded or bolted to the chain links. For very
heavy duty applications, steel flights welded or bolted to the
chain links are still preferred. However, there are several
problems relating to the use of steel flights. One of these is
that they are expensive both due to high material cost and due to
a larye amount of labor required to weld or bolt the steel
flights to the chain links. Another problem of steel flights is
that they are heavy and thereby make the chain difficult to
handle and increase the amount of power xequired to drive the
chain.
Polymeric links are relatively easy to fabricate,
lighter in weight, easy to handle and require less energy to
drive as part of a conveyor chain. Polymeric links may also be
relatively easy to attach to the chain links, however, the mode
of attachment must nevertheless be of sufficient strength to
transfer the driving force of the chain to the flights.
Conveyor flights of both the steel and polymeric type
are subject to undue stresses due to obstructions or binding of
the material being conveyed which provides a force resisting the
1 driving force of the conveyor chain. The result is that the
flight may be d~maged or may be detached from the chain link or
the chain link may be damaged. Breakage of the flight is more of
a problem with polymeric flights than with steel flights due to
the lower strength characteristics of polymeric materials. Thus,
there is a need for improved polymeric flight attachments which
have a greater ability to transfer obstruction or binding
resistive forces to the chain link wi-thout either breaking or
detaching from the link.
It is a general object of this invention to provide a
polymeric flight element for a conveyor chain which has a
structure and is attached to the chain such that the load
carrying force applied to the flight element by the chain and
forces resisting the load carrying force are transferred between
the flight element and the chain in a manner minimi~ing breakage
of the flight element or its detachment from the chain.
The invention is accomplished by providing a polymeric
flight element having a side member attached to a sidebar of a
link of a conveyor chain, a conveyor arm extending laterally from
the side member in-termediate the ends of the side member, and at
least one button positioned on the side member at a distance from
the conveyor arm and projecting from the side member through an
opening in the sidebar and engaging the sides of the sidebar
opening such that force due to the conveying movement of the
chain and forces resisting the con~eying force are transferred
through the buttons to the side member and conveyor arm. By
spacin~ the button at a distance from the arm extending from the
sidebar, the amount of stress on the side member is distributed
along the length of the side membar at the locations of
attachment of the arm to the side member and the location of the
engagement of the button with the sidebar.
The side member may be attached to the chain link
sidebar by a pin integral with the side member and extending
through a hollow rivet connecting parallel chain sidebars. The
button functions as a load carrying means receiving and
transferring a por-tion of the force that would be otherwise
applied to the pin to thus reduce the forces applied to the
1 pin. The conveyor arm of the flight element may have a weakened
area extending across its width. At the weakened area, the arm
bends when obstructed or bound by the material it is moving to
thereby decrease the amount of resis~ing force in the path of the
arm and assist in its being freed of the obstruction or binding
xesistance.
A more thorough understanding oF the present invention
will be gained by reading the following description of -the
preferred embodiments with reference to the accompan~ing drawings
in which:
Figure 1 is a top view o~ a conveyor chain includin~ a
flight element in accordance wi-th the present inven-tion;
Figure 2 is a perspective view of one-half of the
fli~ht element shown in Figure l;
Figure 3 is a broken-away top view, par-tially in
section, of the conveyor chain and flight element shown in Figure
1 ;
Figure 4 is a side view of the chain and flight
element; and
Figure 5 is a top view of a portion of the flight
element showing it in a bent condi-tion.
Referring to Figures 1 and 4, a flight element 2
according to the invention is shown mounted on a conveyor chain 4
which is typically made of steel. The chain 4 comprises a
plurality of inner chain links 6 and a plurality of outer chain
links 8. The inner chain links 6 each include parallel inner
sidebars 10 and 12 respectively having opposite ends 14 and 16
and opposi-te ends 18 and 20. The outex chain links 8 each
include parallel outer sidebars 22 and 24 respectively having
opposite ends 26 and 28 and opposite ends 30 and 32. The ends 14
and 18 and the ends 16 and 20 of the sidebars 10 and 12 are
connected together by bushings 34 which have an interference fit
with the sidebars 10, 12. The connected ends 14, 18 and 16, 20
o~ the sidebars 10, 12 which comprise the inner chain links 6 are
respectively joined by bushings in the form of hollow rivets 36
to ends 26, 30 and 28, 32 of the sidebars 22, 24 of outer links
21~D
1 8- The rivets 36 have an interference fit with the sidebars 22,
24 and a clearance fit with the bushings 34 so that the rivets 36
and -thereby the outer chain links 8 are ~ree to ro-tate relative
to the inner sidebars lO, 12. In the illustrated embodimen-t,
rollers 38 are mounted on the bushings 34.
The flight elements 2 each include two integral, molded
polymeric material conveyor members 42 and 60 which may be
identical to each other. The conveyor member 42 includes a slde
member 46, a pin 48 and a conveyor arm 44 having a weakened area
56. The conveyor member 60 similarly includes a side member 62,
a pin 64 and a conveyor arm 66 having a weakened area 68. Due to
the identity of these elements of the conveyor members 60 and 42,
onl~ components of conveyor member 42 will be described in
detail. The side member 46 is positioned adjacent to and
preferably against the sidebar 22 of outer chain link 8 and
includes ends 50 and 52 respectively juxtaposed with the ends 26
and 28 of the sidebar 22. The conveyor arm 44 extends away from
the chain 4 and transverse to the direction of movement of the
chain at a position intermediate the ends 50 and 52 of the side
member 46.
The conveyor member 60 has an end 88 from which the pin
extends through hollow rivet 36 and the side member 46 of the
conveyor member 42. The side member 46 includes a receptacle 70
having a varying inside diame-ter which corresponds to a varying
outside diameter of the end of the pin 64 such -that the pin 64 is
received with a snap fit in the receptacle 70. ~imilarly, the
pin 48 extending from the end 52 of the side member 46 has a
varying outside diameter which is received with a snap fit in a
receptacle 58 having a varying outside diameter and located at
the end of side member 62. In this manner the conveyor members
42 and 60 are connected together to form the flight element 2 and
are attached to and move with the chain links 8 of the chain 4.
The side member 46 includes a pair of buttons 72 and 74
positioned along the length of the member 46 at a distance spaced
from the arm 44 and projecting toward the sidebar 22. The side
member 62 includes a pair of buttons 76 and 78 positioned along
the length of the member 62 at a distance spaced from the arm 66
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1 and projectlng toward the sidebar 24. The sidebar 22 has a pair
of openin~s 80 and 82 positioned along the length of -the sidebar
22 at positions opposite the but-tons 72 and 74 and the sidebar 24
has a pair of openings 84 and 86 similarly posi.tioned along the
length of the sidebar 24 at positions opposite the buttons 76 and
78. The buttons 72, 74 and 76, 78 respectively project into and
engage the sides of the openings ao, 82 and 84, 86.
In conveying loose material 54 as -the chain 4 moves in
the direction of the arrow (see Figures 1 and 5) along a chute or
trough, typicall~ by pushing the material 54 with the arms 4~ and
6~ of the flight elements 2, obstructions or binding of the
material being conveyed may occur and cause excessive resistance
force to the chain driving force on the arms 44 and 66. The
effort of the chain to move the arms past the obstructions or to
overcome the binding may cause the detachment of the side members
from the chain links and/or the breaking of the pins or conveyor
arms. However, the provision of the buttons 72, 74 and 76, 78
such that they project through the sidebars 22 and 24 and bear
against the sides of the openings 80, 82 and 84, 86 in the
direction of the forces applied to the pins results in the
buttons carrying a portion of the load or forces applied to the
flight elements 2 by the chain 4 or the obstructing forces.
Thus, the full application of such forces to pins 48 and 64 is
prevented. Also important in minimi~ing breakage of the flight
25 elements is the spacing of the buttons 72, 74 and 76, 78
respectively from the positions of the arms 4~ and 66. Such
spacing separates the high stress areas at the locations of the
attachment of the arms to their side members, the engagement of
the huttons with the chain links, and the attachment of the side
members to the chain links through the pins. As a consequence,
the flight elements 2, even though they are made from a polymeric
material, can withstand a much greater resistance to the driving
force of the conveyor chain 4 and the the obstructing forces so
that problems due to breaking of the flight elements or their
detachment from the chain links are considerably decreased.
A further improvement to the flight elements 2 in the
way of avoiding breakage of the elements is the provision of the
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1 weakened lines or areas 56 and 68 which cooperate with the
buttons 72, 74 and 76, 78 to prevent failure of the fliyht
elements 20 In the event that the arms 44 and 66 are unduly
obstructed, they will bend at the weakened areas to assist in the
release of the arms from -the obstruction. ~hus, through the
cooperation of the buttons 72, 74 and 76, 78 and the weakened
areas on the arms 44, 66, the ability of the flight elements 2 to
avoid breakage is considerably enhanced.
It will be understood -that the foregoing description of
the present invention is for purposes of illustration only and
that the invention is susceptible to a number of modifications or
changes, none of which entail any departure from the spirit and
scope of the present invention as defined in the hereto appended
claims.
