Note: Descriptions are shown in the official language in which they were submitted.
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INVERTED CONVEYOR
FIELD OF THE INVENTION
This invention relates to conveyors for transporting parts, products or
materials in
manufacturing, assembly or treatment operations.
BACKGROUND OF THE INVENTION
Overhead conveyors are utilized in various production, assembly and treatment
environments to transport parts of products through various operational
stages. Typically,
such conveyors employ a rotating, generally horizontal drive tube or shaft
that supports
trolleys from which the load is suspended. Wheels on the trolleys ride on the
upper surface
of the rotating drive tube, and each is mounted for rotation about a driven
wheel axis that is
non-parallel and non-perpendicular to the drive tube axis, preferably at an
acute angle to the
drive axis. Overhead conveyors utilizing a drive where the load is suspended
beneath the
drive tube are disclosed, for example, in U.S. patent No. 4,203,511, issued
May 20, 1980 to
Uhing.
Overhead conveyors of this type, however, are restricted to applications in
which the
products being transported may be suspended beneath the drive tube.
Accordingly, belt
conveyors and similar configurations are typically used when it is desired to
transport products
or materials along a path that is spaced above the conveyor drive. However,
belt conveyors
do not provide the advantages of conveyors powdered by a rotating drive tube
in quiet
operation and the safely provided by the friction drive which stops the
advancement of the
conveyed products if resistance to movement is encountered.
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SUMMARY OF THE INVENTION
In an embodiment of the present invention the aforementioned problem is
addressed
by providing a conveyor powered by a rotating, generally horizontal drive
shaft or tube
engaged by angularly disposed trolley drive wheels, wherein trolleys support
the conveyed
products or materials above the drive tube and clear of any parts of the
conveyor structure that
would interfere with the desired path of travel. Each of the trolleys is
provided with load
wheels which ride on load rails above the drive tube and associated drive
wheels, thereby
providing a structure upon which a platform or other support may be mounted
for bearing the
transported products.
In a broad aspect, the present invention provides a conveyor system for
carrying a load
along a generally horizontally extending conveying path comprising: a drive
shaft extending
along the conveying path and mounted for rotation about a shaft axis, at least
one trolley above
said drive shaft and adapted to support a load, and having a plurality of
driven wheels
engaging said drive shaft and mounted for rotation about a corresponding
plurality of driven
wheel axes non-parallel and non-perpendicular to said shaft axis, load rail
structure above said
drive shaft, extending generally parallel thereto and presenting elongated,
upper and lower
running surfaces, said trolley having upper load wheels thereon running on
said upper running
surface, lower load wheels running on said lower running surface, upper and
lower parts
carrying said upper and lower load wheels respectively, and a resilient
element connected with
said parts and yieldably biasing said upper load wheels into running contact
with said upper
running surface, and a product support carried by said trolley above said
drive shaft for bearing
transported products, each of said upper and lower parts being elongated,
extending
longitudinally along the conveying path and having a transverse, inverted U-
shaped
configuration, there being a plurality of said resilient elements connected
with said parts for
yieldably biasing said upper load wheels into running contact with said upper
running surface.
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In another broad aspect, the present invention provides a conveyor system for
carrying
a load along a generally horizontally extending conveying path comprising: a
drive shaft of
consistent diameter presenting a longitudinally continuous surface extending
along the
conveying path and mounted for rotation about a longitudinally extending shaft
axis, at least
one trolley above said drive shaft and adapted to support a load, and having a
plurality of
driven wheels engaging said surface of the drive shaft and mounted for
rotation about a
corresponding plurality of driven wheel axes non-parallel and non-
perpendicular to said shaft
axis, load rail structure above said drive shaft, extending generally parallel
thereto and
presenting an elongated, upwardly facing running surface and a lower,
downwardly facing
running surface, said trolley having upper load wheels thereon running on said
upper running
surface, lower load wheels running on said lower running surface, upper and
lower parts
carrying said upper and lower load wheels respectively, and a resilient
element connected with
said parts and maintaining said load wheels in running contact with said
running surfaces, and
a product support carried by said trolley above said drive shaft for bearing
transported
products, each of said upper and lower parts extending longitudinally along
the conveying path
and having a transverse, inverted U-shaped configuration, there being a
plurality of said
resilient elements connected with said parts for yieldably biasing said upper
load wheels into
running contact with said upper running surface.
Other advantages of this invention will become apparent from the following
description taken in connection with the accompanying drawings, wherein is set
forth by way
of illustration and example, an embodiment of the present invention.
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BRIEF DESCRIPTION OF THE DRAWINGS
[00071 Fig. 1 is a side elevational view of a conveyor powered by a drive tube
beneath
the product support, parts thereof being broken away or shown in broken lines
for clarity (driven
wheels behind the drive tube are shown in full lines).
[00081 Fig. IA is an enlarged view of a portion of one of the trolleys shown
in Fig.1.
[00091 Fig. 2 is a vertical cross-section through the conveyor at a right
angle to the drive
tube, showing a trolley of the present invention as viewed in the direction of
the transporting
path, an upper connecting spring of the trolley being removed for clarity.
[00101 Fig. 3 is a view similar to Fig. 2 showing the trolley including the
upper
connecting spring.
[00111 Fig. 4 is a side elevational view of one of the trolleys of the present
invention
removed from the drive tube and associated conveyor structure for clarity.
[0012] Fig. 5 is a perspective view of the trolley of Fig. 4.
[00131 Fig. 6 is a perspective view similar to Fig. 5 but viewing the trolley
from the
opposite side thereof.
[00141 Fig. 7 is an end view looking essentially along the axis of the
transporting path of
the conveyor.
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DETAILED DESCRIPTION
100151 Referring to the drawings, Fig. 1 illustrates a stretch of a
horizontally extending
conveyor comprising a portion of a horizontal span of a drive beam 10 to which
longitudinally
spaced bearing units 12 are mounted for the purpose of supporting a drive
shaft or tube 14 of the
conveyor system, two trolleys 16 thereof being shown. Legs 18 of upright
supports (one of
which is shown in Fig. 1) elevate the conveyor system in the conventional
manner above a floor
or other underlying surface (not shown) and also maintain a predetermined
spacing between the
drive tube 14 a pair of spaced load rails 20 disposed above the drive tube 14.
As shown in Fig. 2,
an upright frame comprising an inverted, U-shaped hanger assembly 22 supports
the load rails 20
above a cross bar 19. Drive is provided typically by an electric motor 24
coupled via gearbox 26
to a drive pulley 28 connected to drive tube 14 via belt 30.
[00161 Referring particularly to Figs. 3-6, each of the trolleys 16 of the
present invention
is inverted as compared with trolleys of prior overhead conveyors where
products are carried by
the conveyor beneath the trolleys. A yoke plate member 32 carries four driven
wheels 34 as is
clear in Figs. 3 and 5, all of which contact the surface of the drive tube 14.
The axes of the four
driven wheels 34 are at an acute angle with respect to the axis of the drive
tube 14 as is typical in
conveyor systems in order to propel the trolley 16 in an axial direction with
respect to the drive
tube 14 when the latter is driven by the motor 24. The wheels 34 are pressed
into contact with
the drive tube 14 by a vertically oriented coil spring component 36 that is
coaxial with and
surrounds a depending stem 38 (Fig. 3) to which the yoke plate 32 is mounted.
It will be
appreciated that two spaced stems 38 and associated coaxial springs are
employed at the front
and rear of the trolley 16, one of which is seen in the figures. As will be
further appreciated
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hereinbelow, the trolley 16 comprises two vertically spaced parts (spaced
upper and lower
sections 39 and 41) each elongated in the direction of travel and having an
inverted, U-shaped
transverse configuration. The sections 39 and 41 are maintained in operative
interrelationship by
a pair of coil springs 40, both of which can be seen in the side view of Fig.
4. Lateral
displacement is prevented by two pairs of guide wheels 37 on lower section 41
which rotate
about vertical axes and contact the respective inner faces of load rails 20.
[00171 A pair of upstanding trolley tabs 42 (see particularly Fig. 2) each
secured by two
vertically spaced bolts 43 to the center portion of the lower trolley section
41 are received in
respective spaced slots 44 (Figs. 4 and 6) in an elongated, inverted U-shaped
top plate 46 of the
upper section 39 of the trolley and thus permit the upper and lower trolley
sections to be united
and held by the springs 40, upper section 39 being movable vertically on tabs
42 against the bias
of springs 40 to conform to any irregularities in the load rails 20. A channel-
shaped load bar 48
atop the trolley 16 (Fig. 2) has an opening in its base receiving a load bar
pin 53 and is seated on
a thrust bearing 50 and secured by a snap ring 52. The pin 53 is secured by an
upright retaining
screw 51. It should be understood that in Figs. 4-6 the thrust bearing 50 is
directly beneath the
snap ring 52 as the trolley is shown separately removed from the conveyor for
clarity. Installed
and in operation as illustrated in Figs. 1 and 2 supported by two spaced
trolleys 16, the load bar
48 is interposed between the thrust bearing 50 of each trolley and the
associated snap ring 52.
[00181 A horizontal product platform 54 or other support as desired is welded
to the load
bar 48 and thus may receive parts, products or other items as required (not
shown) for movement
along the conveyor line. It should be noted in this respect that platform 54
and the load items to
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be placed thereon are entirely clear of the underlying conveyor apparatus
throughout the desired
path of travel of the conveyed items along the conveyor line.
[00191 The lower, inverted U-shaped section 41 of the trolley body extends
fore and aft
and has four load wheels 56 comprising a front and rear pair thereof as is
clear in Figs. 5 and 6.
Similarly, the upper, inverted U-shaped section 39 has front and rear pairs of
load wheels 58, the
load wheels 58 and 56 cooperating to embrace the two laterally spaced load
rails 20 and run on
the upper and lower surfaces thereof as shown in Figs. 1-3. Therefore, in
operation the four load
wheels 56 of the lower trolley section bear against and ride on the parallel,
elongated lower
surfaces of the two load rails 20, and the four load wheels 58 of the upper
trolley section ride on
the parallel, elongated upper surfaces of the two load rails 20. Accordingly,
under the action of
the two springs 40 that unite the upper and lower trolley sections, the load
wheels 58 and 56
embrace the load rails 20 and run on the top and bottom surfaces thereof and
thus are confined to
the path defined by the load rails 20, while the four drive wheels 34 are
maintained in contact
with the drive tube 14 by the action of springs 36. A transported load on
platform 54 of each
conveyor unit of the system is thus carried and maintained above the
underlying conveyor
apparatus and clear of all of the drive components.
100201 It should be understood that while certain forms of this invention have
been
illustrated and described, it is not limited thereto except insofar as such
limitations are included
in the following claims.
