U.S. patent number 3,669,245 [Application Number 05/002,638] was granted by the patent office on 1972-06-13 for tilt type conveyors.
This patent grant is currently assigned to Aerojet-General Corporation. Invention is credited to George J. Einfeldt, Warren D. Neal, Robert D. Wooten.
United States Patent |
3,669,245 |
Wooten , et al. |
June 13, 1972 |
TILT TYPE CONVEYORS
Abstract
A closed loop conveyor provides a simple arrangement of tracks
on which roll a plurality of cargo carrying devices which are
connected to each other by means of a drive chain adjacent one of
the tracks and which chain is driven by a sprocket wheel. The chain
is of a type having horizontally and vertically pivotal links so
that flexibility is provided whereby the tracks can have horizontal
bends and vertical slope, the cargo carrying devices thus being
enabled to follow a track system which may extend circuitously on
the floor of a warehouse and then rise to another floor and
ultimately return to the first-mentioned floor. The system is
provided with at least one loading station and a plurality of
discharge stations at predetermined places along the track circuit.
Each cargo carrying device has a normally level load carrying
member which can be tilted at any selected station so that cargo
can slide gravitationally into a chute or other conveyor means at
the selected station, on either side of the track. The drive chain
is retained in such a manner that it maintains all of the cargo
carrying devices, such units properly disposed on the tracks
without any need for additional guide members or specially shaped
tracks. The invention is susceptible to use in systems having load
carrying members which are trays of sufficient area to support a
large cargo load, for example, a postal sack, or where the load
carrying members can be relatively narrow slats such that a
plurality of slats support an elongated loading. For example, the
U.S. Pat. to Atanasoff et al. No. 3,233,720, issued Feb. 8, 1966,
and owned by the assignee of the present application, shows a basic
arrangement of a plurality of relatively narrow slats wherein
several slats can carry a large elongated load, such slats being
sequentially tilted at any selected station for discharge.
Inventors: |
Wooten; Robert D. (Rockville,
MD), Neal; Warren D. (Walkersville, MD), Einfeldt; George
J. (Glen Burnie, MD) |
Assignee: |
Aerojet-General Corporation (El
Monte, CA)
|
Family
ID: |
21701733 |
Appl.
No.: |
05/002,638 |
Filed: |
January 13, 1970 |
Current U.S.
Class: |
198/370.04;
198/802 |
Current CPC
Class: |
B65G
47/962 (20130101) |
Current International
Class: |
B65G
47/96 (20060101); B65G 47/74 (20060101); B65g
015/00 () |
Field of
Search: |
;198/154,155,158 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Wegbreit; Joseph
Assistant Examiner: Lane; H. S.
Claims
We claim:
1. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; wherein said track means comprises a pair of spaced channel
members and said chain retaining means comprises a channel member
carried by one of said track members, said chain having a plurality
of rollers disposed in said chain retaining channel member whereby
said rollers are laterally confined by flanges of said latter
channel member; said cargo carrying devices each comprising a load
carrying member and a carriage, pivotal support means whereby said
loading carrying member is tiltably carried by respective carriages
so as to be tilted reversibly in a plane transverse of the plane of
movement of said cargo carrying devices; a tilt control mechanism
incorporated in said track means and comprising a first pair of
cams (225) having a common origin and divergent spacing
therebetween diverging in the direction of movement of said cargo
carrying devices and further comprising an additional pair of cams
(232) having portions spaced inwardly and parallel to respective
cams in said first pair of cams to effect a pair of divergent
channels in correspondingly divergent directions; guide follower
means carried by said cargo carrying devices receivable in either
divergent channel and connected to respective load carrying members
to effect tilt thereof when said guide follower means is received
in one of said channels; including a pair of switch levers for
effecting diverting of said guide follower means selectively to
either divergent channel.
2. A system as set forth in claim 1, wherein each cam of said first
pair of cams has a guide member pivotally mounted at a downstream
end thereof and effecting an elongation of the respective divergent
channel; wherein said guide members can be engaged by and pivoted
out of the path of the guide follower means of load carrying
members which have been previously tilted.
3. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means;
said cargo carrying devices each comprising a load carrying member
and a carriage, pivotal support means whereby said load carrying
member is tiltably carried by respective carriages so as to be
tilted reversibly in a plane transverse of the plane of movement of
said cargo carrying devices; a tilt control mechanism incorporated
in said track means and comprising a pair of cams (225) having
divergent spacing therebetween, said cams diverging in the
direction of movement of said cargo carrying devices; said tilt
control mechanism further comprising an additional pair of cams
(232) having portions spaced inwardly and parallel to respective
cams in said first pair of cams to effect channels in
correspondingly divergent directions; and guide follower means
carried by said cargo carrying devices receivable in said channels
and connected to respective load carrying members to effect tilt
thereof when said guide follower means is received in one of said
channels, including a pair of switch levers to effect diverting of
said guide follower means selectively to either divergent channel;
said switch levers being spacedly mounted and having respective
opposed edges substantially parallel and normally forming a guide
channel intermediate said pairs of cam members, means pivotally
actuating said levers; actuating means for pivotally actuating said
levers; each lever effecting an extension of a side of a respective
divergent channel when it is actuated to thereby effect diverting;
wherein said switch levers effect a path through the spacing
therebetween when not actuated so as to guide said guide follower
means through said tilt control mechanism without effecting
tilting, and wherein either lever, when actuated, guides said
follower means to a respective divergent channel to effect
tilting.
4. A system as set forth in claim 3, and respective spring bias
means for normally maintaining said switch levers in position to
effect said spacing therebetween, said actuating means for said
levers being selectively operable for either lever pivotally.
5. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; said cargo carrying devices each comprising a carriage
having a load carrying member and said load carrying members being
tiltably carried by respective carriages so as to be tilted
reversibly in a plane transverse of the plane of movement of said
cargo carrying devices; a tilt control mechanism and a guide track
leading thereto; said tilt control mechanism comprising a pair of
cams (225) having divergent spacing therebetween, said cams
diverging in the direction of movement of said cargo carrying
devices, and said tilt control mechanism further comprising an
additional pair of cams (232) having portions spaced inwardly and
parallel to respective cams of said first pair of cams to form
divergent channels; respective load carrying members having guide
follower means (132) receivable by said guide track (35) for
guidance to said divergent channels whereby to effect tilting in a
respective rotative direction when said guide follower means is
received in one of said divergent channels, including a pair of
switch levers (238R, 238L) for effecting diverting of said guide
follower means selectively from said guide track into either
channel; each cam of said first pair of cams (225) having a
pivotally mounted extension end (470) thereof effecting an
elongation of the respective divergent channel; the said pivotally
mounted extension ends being engageable by unguided guide follower
means entering said tilt control mechanism so as to be swung out of
the path of said guide follower means, thus permitting said guide
follower means to move unimpeded exteriorly of either divergent
channel.
6. A system as set forth in claim 5, said guide track being
disposed in alignment with the spacing between said switch levers
when said switch levers are not actuated; and cam members disposed
on opposite sides of said guide track to be engaged by any guide
follower means to effect full tilting of the respective load
carrying members in the event that any such guide follower means is
approaching said tilt control mechanism askew of said guide track,
in order to insure clearance of any such guide follower means in
respect to said tilt control mechanism to move without interference
therepast.
7. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; wherein each said cargo carrying device comprises a carriage
having a load carrying member with a support post pivotally carried
by the respective carriage, said load carrying members and said
support posts having a center of gravity disposed in a vertical
plane with the pivotal axis thereof when said load carrying member
is in level position and said center of gravity being disposed
above said pivotal axis, whereby when said load carrying member is
in tilted position it remains in tilted position by virtue of the
displaced center of gravity; said track means including a tilt
control mechanism and having a guide track extending to said tilt
control mechanism upstream thereof and a continuation of said guide
track extending from said tilt control mechanism downstream
thereof; said tilt control mechanism comprising a plurality of
members effecting divergent channels diverging directionally
downstream; switch control means intermediate said divergent
channels comprising levers having a spacing therebetween aligned
with said guide tracks and effecting a central channel in
conjunction therewith and relative to the divergency of said
divergent channels; said support posts having respective guide
follower means movable from said upstream guide track through said
central channel to the downstream guide track and maintaining said
posts vertical so that respective load carrying members are
maintained level when respective cargo carrying devices move past
said tilt control mechanism; means for actuating either of said
switch levers to guide a guide follower means into a diverging
channel for effecting tilt of a respective load carrying member;
cam means (212) upstream of said switch levers disposed adjacent
said upstream guide track to tiltably divert any guide follower
means misaligned in approaching said tilt control mechanism so as
to permit passage thereof without interference with said tilt
control mechanism.
8. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; wherein each said cargo carrying device comprises a carriage
having a load carrying member with a support post pivotally carried
by the respective carriage, said load carrying members and said
support posts having a center of gravity disposed in a vertical
plane with the pivotal axis thereof when said load carrying member
is in level position and said center of gravity being disposed
above said pivotal axis, whereby when said load carrying member is
in tilted position it remains in tilted position by virtue of the
displaced center of gravity; said track means comprising a leveling
mechanism upstream of said drive means for leveling load carrying
members arriving at said leveling mechanism in tilted condition;
said leveling mechanism comprising a pair of fixed converging cam
members and said support posts having guide follower means
engageable with either of said cam members dependent upon
respective direction of tilt of said support posts, whereby said
cam members effecting swinging of support posts to substantially
vertical condition to level respective load carrying members; guide
track means extending from the convergent ends of said cam members
to said drive means to receive said guide follower means as they
leave said convergent ends with the respective posts substantially
vertical; and a pivotal cam plate intermediate said fixed
convergent cam members and pivotally mounted upstream of the
convergency thereof and having a tongue extending downstream and
through the convergency thereof; said pivotal cam plate being
disposed to be engaged by guide follower means for pivotal movement
in either direction; stop means engageable by said tongue to
predetermine the limits of movement of said cam plate upon
engagement by guide follower means; said cam plate having edges
effecting channels in conjunction with respective fixed convergent
cam members whereby any guide follower means engaging said pivotal
cam plate effects pivotal movement to form a channel so as to be
guided thereby in the transition through said leveling mechanism to
said drive means.
9. A system as set forth in claim 8, including cam means upstream
of said leveling mechanism for tilting all load carrying members
arriving thereat in level condition prior to entering said level
mechanism.
10. A system as set forth in claim 9, wherein said cam means
comprises an offset channel leading angularly away from the path of
movement of said cargo carrying devices on said track means; said
system comprising a guide track upstream of said cam means and
extending thereto for guiding any guide follower means into said
latter channel; whereby any load carrying member arriving in level
condition is tilted prior to entry into said leveling
mechanism.
11. In a system as set forth in claim 10, including a pivotal cam
element effecting an extension of a side of said channel and
engageable by any guide follower means of which the load carrying
member is tilted in a direction to effect an engagement on the
outside of said channel; whereby said extension serves for further
tilting guidance of load carrying members arriving in level
condition and wherein said extension is pivotally actuated out of
path of guide follower means when engaged thereby outside said
channel.
12. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; each said cargo carrying device comprising a load carrying
member wherein all of said load carrying members are closely spaced
with respect to each other; said drive means comprising a sprocket
wheel around which said chain passes; each said load carrying
member having a guide follower means; a guide track coacting with
said guide follower means to normally maintain respective load
carrying members in level condition, said guide track passing
arcuately around said sprocket wheel in an arcuate path and being
sloped so as to retain its relative orientation with respect to
guide follower means when said load carrying members are tilted in
passing around said sprocket wheel, said guide track being formed
to move said guide follower means radially inwardly at the upstream
end of said sprocket wheel for effecting positively controlled tilt
of respective load carrying members in order to provide spacing
between the inner radial corners thereof to avoid interference in
passing around said sprocket wheel.
13. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; including load carrying members comprising a plurality of
relatively narrow, closely spaced slats carried by respective cargo
carrying devices; said drive means comprising a sprocket wheel; and
means for tilting said slats to effect spacing between the ends
thereof to avoid interference in passing around said sprocket
wheel.
14. A conveyor system comprising extended track means and plurality
of cargo carrying devices movably supported thereon; a chain
connecting said cargo carrying devices; said chain being flexible
in a horizontal plane and drive means for actuating said chain; and
chain retaining means for confining and guiding said chain whereby
said chain maintains said cargo carrying devices on said track
means; said cargo carrying devices having load carrying members and
means whereby said members are tiltably mounted so as to be tilted
in a plane transverse to the plane of movement for discharging
cargo; said drive means comprising a substantially horizontally
disposed drive wheel encompassed by said chain; levelling means for
ensuring levelling of said load carrying members prior to movement
around said wheel with said chain; and tilt means upstream of said
latter means for ensuring tilt of all load carrying members prior
to movement to said levelling means.
Description
Briefly, the invention contemplates the provision of a simple,
trestle-like support structure for a pair of tracks on which roll a
plurality of carriages, each carriage having a load support member
supported on a pivotally carried post. A guide track is engaged by
each support post roller wherein the support post effects a
vertical level column for support of the respective load carrying
member. Such guide track is intermediate the load carrying tracks
on which the carriages roll and maintains the support post vertical
to maintain a level condition of the respective load carrying
member for loading.
This basic arrangement is not new, being shown in the
aforementioned patent. However, there are several simplifying
differences in the present invention, as compared to the prior
patent, in that the carriages are not directly articulated to each
other as in the prior patent, but are connected by means of a
confined drive chain which also maintains them on the tracks. This
permits a simplicity of mechanical structure as well as affording a
system in which the load carrying members can follow a curvilinear
path in horizontal and vertical planes. The arrangement also
simplifies the actual power drive mechanism as compared with the
prior patent which required the load carrying members to move from
an upper to a lower flight on the return run, whereas in the
present invention the return is accomplished by movement around a
horizontally disposed sprocket wheel. Further, in the prior patent
the tilting of the slats was maintained by means of special side
rails into which the roller of each post of a load carrying member
moved and remained to the very end of the run. In the present
invention such side rails are eliminated and the load carrying
members and their posts are suitably fashioned so that once tilted
they remain tilted by virtue of the center of gravity being shifted
in the tilted position with respect to the pivotal axis.
Other simplifying structure is provided in the present invention as
will be subsequently described and claimed.
A detailed description of the invention now follows in conjunction
with the appended drawing in which:
FIGS. 1A and 1B represent a composite plan view of an over-all
conveyor system of the kind described herein;
FIG. 2 is a fragmentary elevation partially in section, showing one
of the tiltable tray units and the chain drive;
FIG. 2A is a chain detail;
FIG. 3 is an elevation taken on the section line 3--3 of FIG.
2;
FIG. 4 is a fragmentary plan view of one of the tilt control
mechanisms for effective tray tilting;
FIG. 5 is an elevation on the section line 5--5 of FIG. 4;
FIG. 6 is a longitudinal elevation taken on the section line 6--6
of FIG. 4 and showing the solenoid drive for the tilt control
mechanism;
FIG. 7 is a plan view of a device for leveling tilted trays just
prior to their approach to the main drive sprocket wheel of the
conveyor system;
FIG. 8 is a longitudinal elevation on the section line 8--8 of FIG.
7;
FIG. 9 is a longitudinal fragmentary elevation partially in section
of a modification of the invention showing a series of tiltable
slats in level position, together with a common drive chain
therefor, wherein the slats are narrower than the trays in the
direction of travel and a single cargo would be carried on a
plurality of slats;
FIG. 10 is a transverse elevation partially in section showing the
suspension system comprising rollers for one of the slats of the
modification of FIG. 9 and also showing portions of circular guide
tracks utilized in this modification;
FIG. 11 is a plan view of the modification of the invention at the
drive end of a conveyor loop;
FIG. 12 is a fragmentary plan view of a tilt device for ensuring
tilting of all load carrying members prior to being actuated to
level position;
FIG. 13 is a fragmentary plan view of a modified detail of a
tilting mechanism as used at a discharge station.
Referring to FIGS. 1A and 1B, the over-all system comprises a pair
of tracks 10 and 15, suitably supported on structural framework as
indicated at 18 and forming a complete conveyor loop, the
configuration of which is a matter of choice depending on specific
installation and desired location of a loading platform 22 and
discharge stations such as 25. Several loading platforms can be
used.
Rollable on the tracks are a plurality of articulated trays 30
which are maintained in level position by means of certain
components to be described co-acting with a guide track 35 which
extends intermediate the tracks 10 and 15. All of the trays are
articulated by means of a drive chain 40 which makes a complete
loop suitably guided so as to follow the configuration of the
tracks. Each tray is secured to the drive chain 40 and the drive
chain is in turn driven by a large sprocket wheel 45, having
suitable structural bearing support as at 48 on a vertical axis and
being rotated via a chain 52 coupled to a reduction geared motor
55.
Upstream of the drive sprocket wheel is disposed a fixed tilt
channel 58 and leveling means 60 which serve the purpose of tilting
any level tray and then leveling all trays going to the sprocket
wheel.
The directional arrows "D" in FIGS. 1A and 1B show the direction
movement of the trays in their circuit about the loop, and it will
be noted that they pass a loading platform 22 which may be of
manual or automatic type, and subsequently move past discharge
station 25. Prior to each discharge station is a tilt control
mechanism 65, whereby any tray can be tilted in either direction
(FIG. 3) so that cargo thereon can slide in the respective
direction onto a suitable conveyor or other receiving means, e.g.,
a chute at any discharge station 25.
It will be appreciated that tray loading and discharge at selected
stations, and conveyor carry-off thereat can be in accordance with
any programmed system, in accordance with known prior art and which
system does not form any part of this invention.
Suitable guides and wear surfaces are provided for the chain 40,
for example, a channel 68 (also see FIG. 3) and an arcuate
wearstrip 72 around which the chain rolls in traversing any bend in
the system, for example, as shown for the return bend in FIG.
1B.
Normally, channel 68 retains and confines the chain for movement in
a predetermined path, and the chain effects retention of cargo
carrying devices having transversely tiltable load carrying
members, all as hereinafter des-cribed, such retention being on the
tracks 10 and 15 by virtue of confinement of the chain.
Referring to FIGS. 2 and 3, each tray 30 will be seen to have fore
and aft flanges 75a/75b, respectively, with a spacing therebetween
such that the tray is sufficiently long in the direction of travel
and sufficiently wide transversely thereto to carry a cargo unit.
For example, a packing carton or a mail sack which may be of the
order of a couple of hundred pounds in weight or more. Fore flanges
75a are somewhat shorter than flanges 75b, transversely. The tray
is made of stamped, heavy-gauge sheet metal and is supported by a
pair of sheet metal brackets 78 which are bolted as at 82 to
reinforcing ribs such as 85 pressed out of the bottom of the tray.
The brackets 78 have vertical flanges 88 bolted as at 92 to
respective sides of a support post 95 which serves as a column for
supporting the tray and its load. Post 95 has a section 96 with
bearing collar 100 integral therewith from which depends a
tilt-control arm 104 integral with the collar. Collar 100 is
pivotally carried on a pin 108, having its ends supported in
vertical flanges 112, suitably secured as by a welded construction
in conjunction with abutment plates 115 to a base plate 120 of a
tray support carriage 125. The base plate 120 has a suitable
opening 128 through which the arm 104 descends, whereby the arm can
rock on pin 108 in a transverse vertical plane when actuated in a
manner to be described by engagement of a guide roller 132 carried
at the lower end of arm 104. Roller 132 normally rides in the guide
track 35 to maintain the post 95 vertical and the tray level.
Rocking of the post and thus tilting of the tray can be effected by
switch levers and cam mechanism indicated by the reference numeral
65 in FIG. 1B and as shown in detail in FIGS. 4 and 5, later
described.
Still referring to FIGS. 2 and 3, each carriage 125 has side
flanges 135 which carry outrigger rollers such as 138 on stub
shafts, there being four such rollers in order to provide rolling
support for the carriage and thus for the post 95 and tray 30 of
the respective carriage. The rollers 138 roll on horizontal flanges
142 of respective tracks 10 and 15 which may be comprised of
channel members having opposite flanges bolted to the structural
framework 18, as shown in FIG. 3. Thus, tracks 10 and 15 can be
conventional channels bolted as at 146 to side angle members 150
comprised in framework 18, and having floor support members
154.
The guide track 35 may be suitably carried on a horizontal bed
plate 158 of the support structure 18 which comprises trestles 162
made up of angle irons 165 and 166 to which plate 158 is
attached.
The chain 40 (FIG. 3) is retained in chain track 68 which may be a
channel member as shown and suitably secured as by welding to angle
iron members such as 174 periodically spaced and secured to the web
of the channel which comprises track 15. It will be noted that
chain 40 is thus retained in its channel track 68. The chain is
secured as by pins 178 to the base plate 120 of the carriage. As
seen in FIG. 2, each carriage is secured by two spaced pins 178 to
the chain and the spacing between such pins is equal to the pitch
of the chain which is the distance between rollers such as 182 that
ride in the chain track 68. The distance between rollers is, of
course, such as to fit between teeth of the sprocket wheel 45
(FIG.1A) which can be made as radially extending rods for all
practical drive purposes. The chain 40 comprises pairs of parallel
long links such as 184 and short links such as 188. Between each
pair of parallel long links 184 there are short links 188 pinned as
by pins 192 to the adjoining ends of the contiguous long links. The
short links have solid ends through which pass pins 192 via bores,
and are pivotally connected as by pins 196 in a plane at right
angles to the plane of pins 178 and 192. The short links can bs of
a tongue and slot type, as shown in FIG. 2A. Accordingly, chain 40
can pass around bends in a horizontal plane by virtue of pins 178
and 192, and can also bend in a vertical plane by virtue of pins
196.
From the foregoing, it will be appreciated that the conveyor
construction is thus not limited to movement of the trays in a
horizontal plane, but that, in fact, the track construction can be
fabricated to move trays on upward and downward slopes, for
example, from floor-to-floor in a storage warehouse.
It will be noted that the pivotal chain links, such as 184 and 188,
are omitted below the carriage base 120 of the tray, but that chain
tension continuity is provided for by a pair of links such as 200
which extend spacedly between rollers 182 and are connected thereto
at the link ends by the pins 178, which pins being secured to
carriage base 120, ties that base to the chain. The distance
between pins 178 attached to base 120 is not so great as to
preclude movement of the carriage in an arc of suitable radius in a
vertical plane, considering that the local sections of the chain
upstream and downstream of the carriage are provided with
horizontal pivot pins 196 to render sufficiently flexible the
length of chain underlying the respective tray and carriage.
Referring to FIG. 3, the phantom line positions of the tray 30 show
the transversely tilted positions to left and right of the path of
movement for cargo discharge. The carriage 125 has rubber-cushion
bumper buttons 205 which are carried by inclined flanges 208,
extending from the side walls 135. When a tray is tilted, a
reinforcing rib 85 engages one or more buttons 205 to act as a
cushioning stop, in either direction of tilting. The center of
gravity of the tray, or any load carrying member including its'
integral components, is shown generally at C. G., being above the
pivotal axis. Accordingly, the tray remains in either tilted
condition.
Referring to FIGS. 4, 5 and 6, the tilt control mechanism 65 is
illustrated which comprises certain switching elements which the
guide roller 132 engages, in accordance with selected control for
the purpose of rocking the support post 95 by engagement with cam
members to effect tilting of the tray.
In the plan view of FIG. 4 the guide track 35 has an upstream
portion shown as guiding a guide roller 132 (solid lines) toward
the mechanism 65 in the direction of the arrows, and the upstream
portion extends to a pair of triangular horizontal cam members 212
having outward sloping edge surfaces such as 215. In the event of
roller 132 having been previously actuated to tilt its respective
tray, it would necessarily be as shown in phantom in FIG. 3, either
to the left or to the right of the erect position. If either
position shown in phantom in FIG. 3 were retained during the course
of subsequent travel of the tray, roller 132 and respective post 95
would clear switch mechanism 65 without harm. However, owing to
possible mishap, such as failure of a load to slide off a tray and
causing an unbalance,a post 95 and roller 132 may be in a position
such that roller 132 might bounce and drag against the side of the
track 35 on the exterior thereof. In such case, either cam edge 215
would engage roller 132 dependent on which side of track 35 it was
on, to insure full angularity of post 95 so as to clear all
elements of switch mechanism 65 without collision or interference.
The pair of cams 212 are simple triangular plates carried by
vertical guide plates 218 which form short extensions downstream of
the portion of upstream track 35. It will be understood that
assembly of these components can readily be effected as by welding
to track 35 and to a horizontal plate extension 220 and respective
curved guide plates 222.
Plates 222 form initially linear extensions of respective plates
218, and thereafter curve to join respective tilt cams 225, there
being a pair of such cams supported as by welding to respective
angle iron sections 228 and sloping outwardly in the downstream
direction. The cams 225 may be rods or rails which diverge, as
shown in FIG. 4 A pair of inwardly disposed cams 232 having
divergent portions are carried on angle iron sections 235. Thus,
portions of cams 225 and cams 232 are parallel to constitute a
divergent channel on each side of the centerline of travel of the
trays 30 with respect to tracks 10 and 15.
The downstream ends of cams 232 assume parallelism. However, it
should be particularly noted that such downstream ends of cams 232
terminate shortly beyond the switch mechanism 65 as seen in FIG. 4,
and are only long enough to ensure full tilt of post 95. In other
words, once a tray has been tilted it remains tilted by virtue of
its own unbalance until the end of its run as it approaches the
leveling mechanism 60 of FIG. 1A and there is no need to extend
cams 232 for the purpose of maintaining constant engagement with
roller 132 to insure maintenance of tilt.
As seen in FIG. 4 a central guide channel is formed by a sequential
arrangement of members, such channel being indicated by the
straight line of arrows from the upstream end of track 35 to the
downstream continuation guide channel effected by plates 239.
Thus, a composite central guide channel traverses the tilt control
mechanism 65 and is comprised of plates 218, the parallel portions
of plates 222, the opposed respective straight and parallel
portions of a pair of switch arms or levers 238L and 238R, and the
pair of parallel plates 239 which are secured to a base 240.
With the switch levers in the non-actuated position as shown in
full lines in FIG. 4, all rollers 132 will pass through the central
guide channel formed by the above described aligned members and no
tilting will take place.
Actual tilting is readily effected by the downstream divergent
angularity of the cams with respect to the centerline of the track
35 in conjunction with switch arms or levers 238L and 238R.
The cams are given some upward slope although maintaining general
parallelism for the channel portions described, since it is obvious
from FIG. 3 that as roller 132 swings transversely left or right it
is moving upwardly in an arc. Hence, the upward slope insures
engagement of the cams with the roller 132 until ultimately the
roller rides along the downstream segment of either cam 232
parallel to tracks 10 and 15. The tray is then fully tilted for
cargo discharge by gravity, the cargo sliding on to a station
conveyor, e.g, a chute as shown at 25 in FIG. 3.
From all the foregoing, it will be apparent that by virtue of the
center of gravity of the tray and post 95 assembly being displaced
out of the vertical plans containing the pivotal axis of post 95,
such tray once tilted would normally reamin tilted until
subsequently levelled by the instrumentality 60. However, since
mishaps are always possible, the cams 212 are provided upstream of
each switch mechanism 65 so as to render certain full tilt of any
tray in the event that it was not actuated to full tilt position,
or for some reason was swung back in the course of its travel to
less than full tilt position, all as previously set forth.
The support means for the various angle iron sections such as 228
and 235 is comprised of a channel member base 240 to which such
iron angles may be welded and which channel member base 240 has
flanges 241 suspended as by angle iron elements 243 to the lower
flanges of tracks 10 and 15 all as clearly shown in FIG. 5.
Channel member 240 also supports the switch levers 238L and 238R
and solenoid actuators therefor for diverting rollers 132 toward
the left or right by actuation of respective switch levers. Thus,
switch levers 238L and 238R effect diverting of rollers 132 to the
left and right respectively.
Lever 238R is pivoted by pin 258 to the web of base 240 with
suitable spacing collars, as shown in FIG. 5, and the lower end of
the pin has rigidly secured thereto a lever 260 which, as seen in
FIG. 6, is articulated via a link 264 to the plunger 267 of
solenoid 270. Normally, the lever 260 is maintained in position by
a tension spring 274 suitably secured to base 240, so that the
switch lever is maintained in the position shown in solid lines on
FIG. 4. If, however, solenoid 270 is energized, lever 260 is swung
to actuate switch lever 238R to the dotted line position whereat it
blocks the channel from track 35 and plates 218, causing the
approaching roller 132 to ride on the guiding edge cam surface 238R
of the lever so as to ride between the right-hand pair of cams
225-232, as shown in the upper portion of FIG. 4, roller 132
approaching from the right. When the solenoid is de-energized
spring 274 pulls switch lever 238R back to the normal position and,
assuming the levers in the position shown in FIG. 4, all rollers
132 thereafter can then traverse the switch mechanism 65 without
being acted upon, riding between the switch levers and guide plates
carried by base 240 and forming a guide channel to the downstream
portion of track 35 from the channel formed by the spaced
levers.
In a completely similar manner, a respective solenoid 280, acting
through a lever 284 and a pivot pin 288 to which the switch lever
is attached, as well as a spring 292, effects control of switch
lever 238L so as to move it to the phantom line position for
diverting roller 132 to the left to effect tilt by the action of
the cam pair 225-232 at the left of the path of approach of roller
132.
The action for control of switch lever 238L is identical to that of
switch lever 238R, and need not be further described.
Preferably, a rubber cushion bumper, such as pad 296, fastened to
an angle 300 is disposed at each side of a respective switch lever
to cushion the effect of pull back of respective springs, and also
to ensure the switch levers being in proper aligned initial
position to readily permit rollers 132 to pass therebetween when no
tilting is to occur.
It should be noted that the upstream end of switch lever 238L is
bent (FIG. 6) so as to be in a lower plane than the lever 238R, in
order that the levers will not interfere with each other when
either lever is actuated. The extent of actuation of the switch
levers is governed by the extent of travel of the respective
solenoid armatures, although either lever could engage the opposite
pad 296 as a limit stop as will be obvious from FIG. 4.
FIGS. 7 and 8 illustrate the leveling means 60 which levels all
trays prior to reentry to the upstream side of the drive sprocket
wheel 45 (FIG. 1A). Thus, tracks 10 and 15 are fragmentarily
disclosed in FIG. 7, and it will be understood that tilted tray, as
evidenced by the guide roller 132, shown in solid lines for an
exemplary tray, is moved in the direction of the arrows.
The upstream section of guide track 35 terminates prior to the
beginning of the leveling means 60 and a downstream portion begins
at the downstream end, as will be apparent from consideration of
FIG. 7. Thus, the upstream portion of the guide track will, as
noted on FIG. 1A, lead guide rollers such as 132 into the leveling
means, while the downstream portion will receive the rollers, the
trays then being leveled, and guide the tray around the sprocket
wheel 45, maintaining the level condition.
As seen in FIG. 7, the leveling means comprises a bed plate 310
secured in any suitable manner to the tracks 10 and 15. The bed
plate may be a channel having flanges bolted to the tracks, as
indicated, and having a surface flush with the surface of bed plate
158, shown as upstream and downstream sections, and which latter
bed plate supports the guide track 35 as heretofore described,
which is thus interrupted at the leveling means 60.
The leveling means comprises a pair of converging cams 315 which
may be downwardly sloped in the direction of roller movement,
secured as by structural angles 320 to bed plate 310 in a
completely symmetrical arrangement wherein the widest portion of
cams 315 forms a mouth into which rollers 132 in tray tilted
condition have entrance. It will be readily understood that whether
the trays are tilted left or right, one or the other will gradually
swing the roller, and therefore its respective tray, back to a tray
level position, such position being reached at the narrowest
downstream spacing between cams 315 wherein the rollers then pass
through an exit guide track section 324 secured by guide plates 328
to the downstream guide track section 35.
While it might normally be thought that no further mechanism is
required for leveling of trays other than cams 315 which serve as
leveling cams, owing to the speed of travel of the trays and to the
fact that certain trays may arrive at the leveling means in level
condition, it has been found that positive control of tray angle is
highly desirable to prevent wild oscillation and erratic behavior.
In other words, the trays should be kept under positive control at
all times while being manipulated from tilted to level position.
Accordingly, the leveling means also comprises a guide cam plate
330 pivoted as by a pin 334 to bed plate 310 so that it can pivot
in a horizontal plane. The pivot point is upstream of plate 330,
while the downstream end is supporting rollably on a ball 338
suitably carried and secured to the under side of plate 330, as by
a socket 342. Accordingly, plate 330 can swivel from the solid
position shown in FIG. 7 to the dotted line position with a minimum
of friction due to the rolling of ball 338 on the surface of bed
plate 310, and between the limits provided by the extending tongue
end 346 of plate 330 which can engage in either direction with a
cushion pad 350 secured to an angle 353, such limit stop being
provided on each side of exit track 324. Plate 330 will always be
in one position or the other, i.e.the solid and dotted line
positions of FIG. 7, depending on which side the last passing tray
was tilted, being held by friction at pin 334.
The edges of plate 330 are cam-shaped, being identical in shape on
both sides of the plate, which for lightness has a large cutout 356
at its center in order to reduce the effect of angular inertia. The
upstream end of plate 330 is formed with a rounded apex portion 360
of fairly small radius, such that the major portion of the rounded
surface is to one side or the other of the centerline of upstream
track section 35, or at least not dead centered therewith.
It will be apparent that tilted rollers 132 approaching the
leveling mechanism can engage initially either a straight portion
368 or 368a on one side or the other of cam plate 330, or initially
somewhere along a curved portion 365 or 365a leading to the
straight portion, swinging the plate to effect a guide channel in
conjunction with a fixed cam member 315.
Referring to FIGS. 9, 10 and 11, a variation of the invention is
disclosed wherein relatively narrow load carrying members 400 are
utilized of the general type shown in the previously mentioned
patent to Atanasoff et al U.S. Pat. No. 3,233,720. In such type of
narrow slat conveyor system, a plurality of slats carry a single
cargo unit, all as described in that patent. However, where it is
desired to use narrow load carrying members in the present
invention, a problem arises due to interference of the radially
inner ends or corners of the slats in passing around a sprocket
wheel such as the sprocket wheel 45 of FIG. 1A. Due to the close
adjacency of the transverse sides of the slats, when the slats are
angled with respect to each other the corners of adjacent slats
will approach each other and might clash, assuming very close slat
spacing. This problem has been overcome in a very novel manner,
albeit, quite simply, by tilting the slats as they pass around the
sprocket wheel.
Thus, as seen in FIGS. 9, 10 and 11 all reference characters
previously used are repeated for identical or substantially
identical parts, and hence no further description thereof need be
given. However, the normally straight guide track 35, as seen in
FIG. 9, is deflected inwardly in a bent section 410 as seen in FIG.
11, radially closer to sprocket wheel 45, and then passes arcuately
about sprocket wheel 45 below the chain wearplate 413 leaving the
downstream side thereof in the outwardly bent section 415.
The arcuate portion of track 35 is sloped as indicated by the
fragmentary portion 420 in FIG. 10 in order to maintain the flanges
of the channel section parallel to the axis of the guide roller 132
which remains in the track. Thus, due to the inward bend at 410,
each slat is tilted in turn so that their outer ends move
downwardly to thereby open a spacing such as 425 at the inward
ends, between slats, in order to prevent corner interference.
At the downstream bend 415 the slats are once more tilted to level
condition.
Referring particularly to FIG. 9, it will be noted that the chain
430 is somewhat different from the chain 40 of FIG. 2 in that only
single links are needed between carriages 125, this being due to
the closer spacing of the carriages when narrow slats 400 are used.
However, the biplanar construction of the chain is carried out in
the same manner by means of vertically and horizontally disposed
pins, as heretofore described in connection with FIG. 2 and as will
be readily understood by persons skilled in the art.
While a channel like the channel 68 (FIG. 3) for the chain could be
circuitously formed to guide the chain around the bend (FIGS. 1B
and 10), it has been found expedient to use a wear strip 413, of
plastic material, e.g., polyurethane. Such strip can readily be
secured as by rivets (not shown) to the inner track.
It will be appreciated that a wear strip is usable also for the
double link chain of FIG. 2. Such wear strip 72 is shown in FIG.
1B.
As seen in FIG. 10, a channel 435 guides the rollers 178 at one
side of the carriage 125 and has a flange above such rollers.
Such channel 435 is preferably used around the radially inner
rollers to ensure no vertical movement of the carriage and chain
above the inner support track 10 and wear strip 413 (FIG. 1B). The
channel is also used, but not shown, to capture the outer rollers
of carriage assemblies traveling around the drive sprocket wheel to
ensure no undesirable tilting of the carriage.
It has been found preferable to provide tilt of all trays prior to
their entry to the leveling means 60 and a device is shown in FIG.
12, indicated by the reference character 58 in FIG. 1A, to make
certain that all trays are tilted prior to entry to the leveling
mechanism. Thus, in FIG. 12, a base plate 450 of the same type
heretofore described for the base plate 240 is secured between the
tracks in the same manner as base plate 240 (FIG. 5) and carried on
the base plate is a fixed cam 455, generally S-shaped, and which
may be of rod construction such as cams 225 and 232 (FIGS. 5 and
6).
A parallel cam comprises the fixed cam 460 having a pivotal cam 470
disposed as an extension thereof and pivoted as by a pin 475 to the
base plate.
Accordingly, the fixed cams 455, 460 and pivotal cam 470 effect a
channel 472 from the downstream end of guide track 35 for guide
rollers of level load carrying members such as rollers 132, as have
heretofore been previously discussed, and such channel causes
tilting by virtue of the lateral offset or bending of the channel
so that when such rollers arrive at the leveling mechanism 60 their
load carrying members are fully tilted and then enter the levelling
mechanism to be levelled before going to the sprocket wheel 45 of
FIG. 1A.
The pivotal cam 470 which forms an extension end of the cam 460 may
be a bar suitably curved to give smooth roller path transition and
may as a matter of design rise upwardly in a vertical plane so as
to continue the upward rise of cam 460 for the purposes of
remaining in assured contact with rollers as they are tilted and
thus move in an ascending arc (FIG. 3) to tilt position. Such
upward rising of the cams is illustrated for the cams 225 and 232
on FIG. 6.
Sleeves or collars may be utilized below cam 470 in order to
situate it at the proper initial level at the pivot pin 475.
Persons skilled in the art will fully understand the construction
and design of cams for effecting the functions described and no
further detailed discussion need be given. However, at this point
it might be mentioned that all cams utilized in this system could
be level and have no upward rise provided rollers 132 had
sufficient axial length to maintain contact with them during the
course of being tilted and while moving transversely in an upward
swing, FIG. 3 illustrating such upward swing in degree for full
tilt.
Further referring to FIG. 12, it will be appreciated that the
construction provides for tilting of any level load carrying member
when it arrives at the tilting mechanism 58 coming from the
direction of the right hand arrow A. However, should a load
carrying member arrive in already tilted condition, the roller 132,
shown in full lines, will engage cam 470 and swing in out of the
way so as to pass unimpeded to the leveling mechanism 60. Likewise,
should a load carrying member be tilted in opposite direction so
that the roller is approaching on the opposite side of the channel
472 it will simply traverse the tilting mechanism without engaging
any component.
The pivoted cam member 470 need not be biased to any position. The
pivotal pin mount is made suitably tight to effect a frictional
holding effect for the position shown, or if this cam be swung by a
tilted roller 132 so as to block channel 472, then any roller
coming therethrough will push it back to the position shown. The
vertical flange of base plate channel 450 serves as a stop for such
return movement.
Referring to FIG. 13, a fragmentary portion of a switch lever
mechanism of the type shown in FIG. 4 is illustrated, all reference
characters being identical with that on FIG. 4, and wherein a
pivotal cam extension end 470 as hereinabove described has been
pivoted as by a pin 475 to the base plate 240. The purpose and
action of the pivotal cam member 470 is precisely as described in
connection with FIG. 12 and need not be repeated save to say that
it effects a smooth transition for rollers passing between the cams
225 and 232 in being transversely actuated to tilt load carrying
members. Obviously, both of the cams 225 shown in FIG. 4 would be
provided with such end cam members 470 as mirror images of each
other so that either of the divergent channels would afford smooth
tilting transitions.
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