U.S. patent number 3,877,386 [Application Number 05/412,130] was granted by the patent office on 1975-04-15 for apparatus for controlling conveyance of articles.
This patent grant is currently assigned to Nakanishi Metal Co., Ltd.. Invention is credited to Takao Wakabayashi.
United States Patent |
3,877,386 |
Wakabayashi |
April 15, 1975 |
Apparatus for controlling conveyance of articles
Abstract
A conveyor system comprises a first conveyor for conveying
articles and a second conveyor disposed at one end of the first
conveyor transversely thereof for receiving the articles therefrom.
The second conveyor, adapted to accumulate the articles, includes a
plurality of support rollers arranged in two rows longitudinally
thereof, a drive chain interposed between the two rows of rollers,
pushers tiltably mounted each at the approximate midportion of its
length on the drive chain at specified spacing and each having an
upper end projecting upward from the chain to engage the article
and a lower end carrying a roller and projecting downward from the
chain, and levers tiltably mounted each at the approximate
midportion of its length on the drive chain and positioned in front
of the pushers in mating combination therewith, each of the levers
being adapted to be pushed down by contact with a stopped article
while travelling with the drive chain and to thereby tilt the
mating pusher. Disposed forwardly of the first conveyor in opposing
relation to the front end thereof and under the drive chain of the
second conveyor is a cam upwardly movable to come into contact with
the roller at the lower end of the pusher to position the pusher
upper end below the upper end of the support roller and downwardly
movable out of contact with the lower end of the pusher. At the end
of the first conveyor, there are provided pushing members pivotally
reciprocally movable between an upper position and a lower position
with respect to the upper ends of article supporting rollers
included in the first conveyor. When moving from the lower position
to the upper position, the pushing members come into contact with
the rear end of the article to push the article toward the second
conveyor and to thereby discharge the article completely from the
first conveyor at the upper position. Further disposed forwardly of
the first conveyor are receiving members pivotally reciprocally
movable between an upper position and a lower position with respect
to the upper ends of article supporting rollers of the second
conveyor. At the upper position, the receiving members receive the
article sent out from the first conveyor and, in the course of the
forward movement from the upper position, the receiving member
place the article onto the support rollers of the second
conveyor.
Inventors: |
Wakabayashi; Takao (Osaka,
JA) |
Assignee: |
Nakanishi Metal Co., Ltd.
(Osaka, JA)
|
Family
ID: |
14538733 |
Appl.
No.: |
05/412,130 |
Filed: |
November 2, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Nov 4, 1972 [JA] |
|
|
47-110553 |
|
Current U.S.
Class: |
104/172.1;
198/426; 198/465.1; 198/602; 198/732; 198/463.3; 198/598;
198/721 |
Current CPC
Class: |
B65G
19/265 (20130101) |
Current International
Class: |
B65G
19/00 (20060101); B65G 19/26 (20060101); B61b
013/00 () |
Field of
Search: |
;198/2R,21,24,106,168,170,172,173 ;104/88,172R,172BR,172B,172C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Keen; D. W.
Attorney, Agent or Firm: Armstrong, Nikaido & Wegner
Claims
What I claim is:
1. In a conveyor system having a first conveyor for conveying
articles and a second conveyor disposed at one end of the first
conveyor transversely thereof for receiving the articles from the
first conveyor, an apparatus for controlling conveyance of articles
comprising the second conveyor including a number of rotatable
supporting members arranged in two rows longitudinally thereof for
supporting the articles, a drive chain interposed between the two
rows of supporting members in parallel thereto and positioned below
the supporting members, a number of normally raised pushers
tiltably pivoted, each at an intermediate portion of its length, to
the drive chain at specified spacing and each having an upper
projection and a lower projection, the upper projection being
engageable with an article on the supporting members when in its
raised position and disengageable from the article when tilted and
means for tilting the pusher engaging an advancing article when the
article approaches a preceding article stopped during transport; an
upwardly and downwardly movable cam disposed forwardly of the first
conveyor in opposing relation to the front end thereof and
positioned under the drive chain of the second conveyor, the cam
having a horizontal upper surface of a length approximately equal
to the width of the first conveyor and downwardly slanting surfaces
at its front and rear ends respectively, the cam being operable to
push up the lower end of the pusher by the horizontal upper surface
when moving upward to bring the upper end thereof down to a level
lower than the supporting members and to bring the horizontal upper
surface out of contact with the lower end of the pusher when moving
downward; and means for transferring the conveyed articles from the
first conveyor onto the second conveyor.
2. The apparatus for controlling conveyance of articles as set
forth in claim 1 wherein the pusher is maintained in its raised
position under gravity acting on the portion thereof below a pivot
supporting the pusher, the lower end of the pusher projecting
downward from the drive chain and being provided with a roller
rollable on the cam.
3. The apparatus for controlling conveyance of articles as set
forth in claim 1 wherein the pusher tilting means comprises levers
disposed in front of the pushers in mating combination therewith
respectively, each of the levers having an upper projection, lower
projection, a roller mounted on the upper projection and rollable
in contact with the under surface of the article, a rear projection
extending from the upper projection toward the pusher and a link
connecting the rear projection to a front projection extending from
the pusher toward the lever, each of the levers being tiltably
pivoted to the drive chain at an intermediate portion of its length
and normally maintained in its raised position under gravity acting
on the portion thereof below its pivot, whereby the pusher is
rendered tiltable in operative relation to the tilting of the
lever.
4. The apparatus for controlling conveyance of articles as set
forth in claim 1 wherein the transferring means is disposed at the
end of the first conveyor and comprises means for pushing out the
conveyed articles on the first conveyor from the same conveyor
toward the second conveyor and means for receiving the articles
pushed out from the first conveyor by the pushing means and
transferring the articles onto the rotatable supporting members of
the second conveyor.
5. In a conveyor system having a first conveyor for conveying
articles and a second conveyor disposed at one end of the first
conveyor transversely thereof for receiving the articles from the
first conveyor, an apparatus for controlling conveyance o f
articles from the first conveyor, an apparatus for controlling
conveyance of articles comprising the second conveyor including a
number of rotatable supporting members arranged in two rows
longitudinally thereof for supporting the articles, a drive chain
interposed between the two rows of supporting members in parallel
thereto and positioned below the supporting members, a number of
normally raised pushers tiltably pivoted, each at an intermediate
portion of its length, to the drive chain at specified spacing and
each having an upper projection and a lower projection, the upper
projection being engageable with an article on the supporting
members when in its raised position and disengageable from the
article when tilted and means for tilting the pusher engaging an
advancing article when the article approaches a preceding article
stopped during transport; an upwardly and downwardly movable cam
disposed forwardly of the first conveyor in opposing relation to
the front end thereof and positioned under the drie chain of the
second conveyor, the cam having a horizontal upper surface of a
length approximately equal to the width of the first conveyor and
downwardly slanting surfaces at its front and rear ends
respectively, the cam being operable to push up the lower
projection of the pusher by the horizontal upper surface when
moving upward to bring the upper projection thereof down to a level
lower than the supporting members and to bring the horizontal upper
surface out of contact with the lower projection of the pusher when
moving downward; means disposed in the end of the first conveyor
for pushing out the conveyed articles of the first conveyor from
the same conveyor toward the second conveyor; and means disposed at
the end of the first conveyor for receiving the articles pushed out
from the first conveyor by the pushing means and transferring the
articles onto the rotatable supporting members of the second
conveyor.
6. The apparatus for controlling conveyance of articles as set
forth in claim 5 wherein the pushing means includes frames disposed
in the first conveyor, a rod rotatably supported by the frames
transversely thereof, pivotal members fixed to the rod proximate to
the opposite ends thereof respectively and extending upward, an ear
extending downward from the midportion of the rod and a hydraulic
cylinder having a piston rod with an end pivoted to the ear,
whereby the pivotal members are rendered reciprocally movable
between an upper position and a lower position with respect to the
upper ends of rotatably supporting members of the first conveyor,
the pivotal members being operable to push an advancing article
toward the second conveyor in contact with the rear end of the
article when moving upward from the lowered position so as to
discharge the article completely from the first conveyor when in
the elevated position.
7. The apparatus for controlling conveyance of articles as set
forth in claim 5 wherein the receiving and transferring means
comprises frames disposed in the second conveyor, two rods
rotatably supported by the frames transversely thereof and spaced
apart by a specified distance, pivotal members fixed to each of the
rods proximate to its opposite ends respectively and extending
upward, rollers each rotatably mounted on the upper end of each of
the pivotal members, downardly extending levers each fixed to one
end of each rod, a link interconnecting both the levers and a
hydraulic cylinder having a piston rod with its distal end pivoted
to an intermediate portion of one of the levers, the rollers on the
pivotal members having their support pins positionable at right
angles to those of the supporting members of the second conveyor
and in alignment with supporting members of the first conveyor, the
rollers further being positionable slightly above the rotatable
supporting members of the second conveyor but at the same level as
the rotatable supporting members of the first conveyor, the pivotal
members thus being reciprocally movable between an upper position
and a lower position with respect to the upper ends of the
rotatable supporting members of the second conveyor to receive an
article sent out from the first conveyor when in elevated position
and to place the article onto the rotatable supporting members of
the second conveyor in the course of downward movement from the
elevated position.
8. The apparatus for controlling conveyance of articles as set
forth in claim 5 wherein a pair of article discharging chains are
disposed in the front portion of the first conveyor and followed by
its drive chain, each of the discharging chains being equipped with
at least one pusher for pushing the articles from behind.
9. The apparatus for controlling conveyance of articles as set
forth in claim 5 wherein each of the first and second conveyors is
provided with a pair of guide rails extending along the opposite
sides of the articles to be conveyed, and at the junction of both
the conveyors one of the guide rails of the second conveyor is
partially removed over a distance corresponding to the space
between the pair of guide rails of the first conveyor to form an
opening at the removed portion, the first conveyor further
including pivotal members composed of bars secured to a rod and
rollers each mounted on the upper end of each bar, the rollers
being horizontally positionable at the opening when the pivotal
members are at an elevated position so as to cooperate with the
guide rails of the second conveyor.
10. The apparatus for controlling conveyance of articles as set
forth in claim 5 wherein the article to be conveyed is a pallet
including lugs attached to the midportions of its four sides
respectively with which the pusher is engageable from inside, guide
rails each extending between each pair of the lugs opposing each
other to guide rollers on levers and slider surfaces extending
lengthwise and widthwise of the pallet respectively for movable
contact with the rotatable supporting members of the first and
second conveyors.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for controlling
article conveying operation, more particularly to an apparatus to
be incorporated in a conveyor system having a first conveyor for
conveying articles and a second conveyor disposed at one end of the
first conveyor transversely thereof to receive the articles from
the first conveyor, the apparatus being operable to control the
article conveying operation of the first and second conveyors.
Throughtout the specification and the appended claims, the terms
"front" or "forward" and "rear" or "rearward" are used with respect
to the direction of travel of the conveyor. Thus "forward" refers
to the direction of advance of the conveyor, while by "rearward" is
meant the direction opposite thereto.
In the case where articles are transported on conveyors, there
arises a need to stop the articles in the course of conveying
operation at an intermediate position of the path of travel of the
articles for working, inspection, testing or like purposes. On such
occasion, it is more convenient to accumulate a number of articles
in the form of a row of closely arranged articles than to leave
them separated from each other. To assure such convenience,
conveyors have already been provided and put to use which comprise
a drive chain having a number of pushers mounted thereon at
specified spacing and engageable with and disengageable from the
articles to be conveyed and rotatable support members adapted to
merely support the articles so as to accumulate the articles.
If the aforementioned second conveyor is used as a main conveyor
for conveying articles all the time, with the first conveyor
serving as a branch conveyor for transferring the articles onto the
second conveyor or main conveyor only when so required, it will be
more advantageous to employ a conveyor of the accumulation type for
the second conveyor at least for the foregoing reason. However, the
conveying system will then involve the following problem. Since the
accumulation-type conveyor has the construction described, the
pushers on the drive chain invariably project upward from the
rotatable support members and therefore impede the transfer of the
articles from the first conveyor onto the second conveyor.
Furthermore, inasmuch as the direction of advance of the first
conveyor and that of the second conveyor intersect each other at
right angles, it is difficult to transfer the articles
smoothly.
These difficulties heretofore experienced have made it impossible
to employ the accumulation-type conveyor for the second or main
conveyor.
SUMMARY OF THE INVENTION of comprising drive
The object of this invention is to provide an apparatus for
controlling conveyance of articles employable in a conveyor system
including a first conveyor and a second conveyor connected thereto
in a T-shaped arrangement and serving as the main conveyor so as to
permit the use of a conveyor of the accumulation type as the second
conveyor. The second conveyor according to this invention comprises
a number of article supporting rotatable members arranged in two
rows longitudinally thereof; a drive chain interposed between the
two rows of supporting members in parallel thereto and positioned
below the supporting members; a number of normally raised pushers
tiltably pivoted, each at an intermediate portion of its length, to
the drive chain at specified spacing and each having an upper
projection and a lower projection, the upper projection being
engageable with an article on the supporting members when in raised
position and disengageable from the article when tilted; and means
for tilting the pusher in engagement with an advancing article when
the article approaches a preceding article stopped during
transport, whereby when the desired one of a great number of
articles is stopped the following articles can be brought to a halt
one after another in accumulated fashion.
Disposed forwardly of the first conveyor in opposing relation to
the front end thereof and positioned under the drive chain of the
second conveyor is an upwardly and downwardly movable cam having a
horizontal upper surface of a length approximately equal to the
width of the first conveyor and downwardly slanting surfaces at its
front and rear ends. The lower projection of the pusher projecting
downward from the chain is pushed upward by the horizontal surface
when the cam ascends to bring the upper projection of thereof down
to a level lower than the supporting members. When descending, the
horizontal surface moves out of contact with the lower projection
of the pusher. When the article is to be transferred from the first
conveyor to the second conveyor, the article advancing on the first
conveyor is brought to a halt just before the junction between the
two conveyors. Simultaneously with this, the pusher on the drive
chain of the second conveyor which pusher is positioned in front of
the front end of the first conveyor over the distance corresponding
to the width of the first conveyor is lowered by the cam to a level
below the upper ends of the rotatable supporting members so that
the pushers will not interfere with the article to be transferred
onto the second conveyor. The apparatus further includes means for
transferring articles from the first conveyor onto the second
conveyor, whereby the articles can be transferred from the former
to the latter free of trouble, although the direction of travel of
the former intersects that of the latter at right angles.
This invention will be described below in greater detail with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view showing an embodiment of the apparatus for
controlling article conveying operation of this invention wherein
the T-shaped junction of a first conveyor and a second conveyor is
illustrated;
FIG. 2 is a view in section taken along the line II--II in FIG. 1,
part of the first conveyor being broken away;
FIG. 3 is a side elevation showing the second conveyor in FIG. 1
partly broken away to illustrate article receiving and transferring
means;
FIG. 4 is a bottom view of a pallet which is the article to be
conveyed;
FIG. 5 is a side elevation of the pallet;
FIG. 6 is a front view of the pallet;
FIG. 7 is a plan view on an enlarged scale showing part of a drive
chain having a pusher and a pusher tilting lever in combination
therewith;
FIG. 8 is a view in section taken along the line VII--VII in FIG.
7;
FIG. 9 is a side elevation of the drive chain of FIG. 7, the view
particularly showing an article in engagement with the pusher and
advancing with the drive chain as it is approaching a preceding
stopped article, the articles being shown partly in section;
FIG. 10 is a side elevation corresponding to FIG. 9 and showing the
drive chain in FIG. 9 in further advanced position and front and
rear articles in accumulated state;
FIG. 11 is a side elevation corresponding to FIG. 7 and showing the
article while advancing in engagement with the pusher in the
absence of a stopped article and when a cam is in its lowered
position; and
FIG. 12 is a side elevation corresponding to FIG. 11 and showing
the cam in its elevated position and the pusher and the lever for
operating the pusher as positioned below the upper ends of the
supporting rollers.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 to 3, there is shown a conveyor system
including a first conveyor 1 for conveying articles and a second
conveyor 2 disposed at one end of the first conveyor 1 transversely
thereof for receiving the articles from the first conveyor 1. The
second conveyor 2 serves as the main conveyor. The second conveyor
2 includes posts 3 spaced apart by a specified distance
transversely thereof in pairs and disposed at predetermined spacing
longitudinally of the conveyor 2. A beam 4 extends between and
secured to the transverse pair of posts 3 at the approximate middle
of height of the posts. Mounting plates 5 are fixed to one side
surface of each beam 4 toward the opposite ends of the beam
respectively. Longitudinal bars 6 at right angles to the beams 4
and extending in parallel to each other lengthwise of the second
conveyor 2 are fixed to the upper ends of the mounting plates 5. A
number of support rollers 7 are mounted on each of the longitudinal
bars 6 at specified spacing longitudinally thereof. Toward the
midportion of each beam 4, a pair of vertical angle bars 8 are
secured to the beam as if in suspension. Secured to the upper ends
of the angle bars 8 are upper rails 9 extending longitudinally of
the second conveyor 2 at right angles to the beams 4 and having a
U-shaped cross section, with their opening sides opposing each
other. Like the upper rails 9, lower rails 10 L-shaped in cross
section are secured to the angle bars 8 at their lower ends. At the
center of the second conveyor 2, an endless chain 11 extends
between and in parallel to the two rows of support rollers 7, the
chain 11 being positioned at a lower level than the rollers 7. The
endless chain 11 is provided on its opposite sides with rollers 12
rollable along the rails 9 and 10, the rollers 12 being mounted on
each connecting portion of the links constituting the chain 11. The
chain 11 is driven by an unillustrated electric motor and known
transmission means, with the upper side of the chain travelling in
the direction of the arrow in FIG. 1 all the time. Guide rails 13,
C-shaped in cross section, are secured to the two rows of posts 3
arranged longitudinally of the conveyor 2 at the inner sides of
upper ends of the posts. The opening sides of the rails 13 are
directed outwardly of the conveyor 2.
FIGS. 7 to 10 show the details of the drive chain 11, especially
the pushers and levers for tilting the pushers. The chain 11
comprises pairs of inner links 14 and pairs of outer links 15
arranged alternately and connected together by pins 16 each
carrying the rollers 12 at its opposite ends respectively. Inner
links 17 spaced by a distance greater than the length of articles P
are formed at their opposite ends with upstanding portions 18 and
19 unlike the other inner links 14. Each pusher 21 is tiltably
mounted, at an intermediate portion of its length, on the rear
upstanding portions 19 by means of a pivot 20. The pusher 21 is
composed of two plates connected together and spaced by a
predetermined distance and has an upper projection 21a projecting
obliquely upward and engageable with the article P, a lower
projection 21b of a greater width carrying a roller 22 on a pin 23
at its lower end and projecting downward from the chain 11, and a
front projection 24 extending horizontally forward approximately
from the position of the pivot 20. A tiltable lever 26 mating with
the pusher 21 to tilt the same is mounted, at an intermediate
portion of its length, on the front upstanding portions 18 by means
of a pivot 25. The lever 26 is composed of two plates connected
together and spaced by a smaller distance than the two plates of
the pusher 21. The lever 26 has an upper projection 26a carrying a
roller 27 on a pin 28 at its upper end, a rear projection 29
extending substantially toward the pusher 21 and overlapping the
front projection 24 of the pusher 21, and a lower projection 26b
having a lower end slight projecting from the lower end of the
links of the chain 11 and having a large width. A vertical link 30
is interposed between the front projection 24 of the pusher 21 and
the end of rear projection 29 of the lever 26. The link 30 is
pivotally connected, at its upper end, to a pin 31 on the end of
rear projection 29 and, at its lower end, to a pin 32 on the end of
front projection 24. Both the pusher 21 and lever 26 are normally
maintained in raised position under gravity acting on the portions
thereof under the pivots 20 and 25 respectively, and the vertical
front surface of the lower projection 21b and the vertical rear
surface of the lower projection 26b abut against the pins 16
positioned immediately below the pivots 20 and 25 respectively,
whereby they are made retainable in position. More specifically,
the pins 16 serve as stoppers for preventing the upper projection
21a of the pusher 21 from turning rearward from the raised position
and for preventing the upper projection 26a of the lever 26 from
turning forward, respectively. The upper end of upper projection
21a of the pusher 21 is positioned above the roller 27 of the lever
26. The article P on the second conveyor 2 is supported on the
rollers 7 and travels with the drive chain 11 by virtue of
engagement with the pusher 21 on the chain 11, with its widthwise
side surfaces moving along the guide rails 13.
The first conveyor 1 shown in FIGS. 1 and 3 is of the accumulation
type substantially the same as the second conveyor 2. However, the
front part of the frist conveyor extending from its front end some
distance rearward includes a pair of endless chains 34 disposed in
parallel side by side longitudinally of the conveyor and equipped
with pushers 33 only, the chains 34 being adapted to send out the
articles. Pushers 33 are mounted on the links of the chains 34 in
upright position and carry rollers 42 at their upper ends. Provided
in the rear of the chains 34 in overlapping relation thereto is a
drive chain which is substantially equivalent to the drive chain 11
incorporated in the second conveyor 2 and equipped with pushers 21
and levers 26. By an electric motor and transmission means, both
the chains are driven in synchronism, with the upper sides thereof
travelling in the directions of arrows in FIGS. 1 and 2. Since the
drive chain of the first conveyor 1 is not different from the drive
chain 11 of the second conveyor 2 as described above, it is not
shown in the drawings. Sprocket wheels 35 around which the chains
34 are reeved (rear sprocket wheels, not shown) are mounted on a
shaft 38 supported by bearings 37 on outer frames 36. A pair of
longitudinal bars 39 extending in parallel longitudinally of the
first conveyor 1 are provided, on the inner surfaces thereof, with
a number of rollers 40 arranged at specified spacing. The upper
ends of rollers 40 of the first conveyor 1 are positioned at a
slightly higher level than the rollers 7 of the second conveyor 2.
Guide rails 41 disposed outside the longitudinal bars 39 are
positioned above the guide rails 13 of the second conveyor 2 by the
difference in level between the rollers 40 and the rollers 7. One
of the two guide rails 13 in the second conveyor 2 which is
positioned toward the first conveyor 1 is partially cut away at the
junction of the first conveyor 1 and the second conveyor 2 to form
an opening 43, the removed length of the rail corresponding to the
space between the two guide rails 41 of the first conveyor 1.
With the first conveyor 1, each article P is supported on the
rollers 40 and is advanced by virtue of engagement with the pusher
on the drive chain while the lengthwise sides thereof are being
guided by the rails 41. When approaching the front end of the first
conveyor 1, the article is freed from engagement with the pusher
but is subsequently engaged by the pushers 33 on the chains 34,
whereby it is sent forward. If the chain corresponding to the drive
chain 11 should extend to the front end of the first conveyor 1,
the pusher which has been in engagement with the front end of the
article P would be moved out of engagement with the article P when
the drive chain travels around the periphery of the associated
sprocket wheel as will be apparent from the drawing, allowing the
article to remain on the support rollers 40 instead of being
forwarded toward the second conveyor 2. Supposedly, the succeeding
pusher would push the article P forward, but the pusher-tilting
lever positioned in front of the particular pusher will then come
into contact with the article P to move the pusher downward before
the pusher engages the rear portion of the stopped article P as
will be described later. Consequently, the succeeding pusher will
pass away under the bottom of the article without engagement. For
this reason, the article discharging chains 34 are used. The chains
for sending out the articles may alternatively be of a known
construction.
The first conveyor 1, which is employed as a branch conveyor, need
not necessarily be of the accumulation type but may be a usual belt
conveyor, chain conveyor, drive-type roller conveyor or the like.
Apparently, the article discharging chains 34 can then be dispensed
with.
In the present embodiment which is given for illustrative purposes
only, the article P to be conveyed is exemplified as a pallet,
which is specifically shown in FIGS. 4 to 6 and FIGS. 9 to 12. The
pallet comprises a rectangular loading plate 44 as a main body.
Projecting downward from the under surface of the loading plate 44
at the midportions of its four sides are lugs 45 and 46 with which
the upper projection 21a of the pusher 20 on the drive chain 11 is
engageable from inside. Rails 47 and 48 of inverted hatlike cross
section for rolling contact with the roller 27 of the lever 26
extend between the pair of lugs 45 opposing each other lengthwise
of the loading plate 44 and between the pair of lugs 46 opposing
widthwise of the loading plate, respectively. These rails are
secured to the under surface of the loading plate 44. The rails 47
and 48 have a width which is smaller than the space between the two
plates constituting the pusher 21 and are formed, each at its
opposite ends, with upwardly slanting portions 47a and 48a for
permitting the roller 27 to come into or out of rolling contact
with the rails smoothly. Of course, the lugs 45 and 46 have a
greater width than the rails 47 and 48 so that the two plates of
the pusher 20 can contact therewith. Further to enable the roller
27 to come into or out of rolling contact with the rails, the lower
ends of the lugs 45 and 46 coincide with the outer ends of the
slanting portions 47a and 48a. The loading plate 44 is fixedly
provided on its under surface with pairs of parallel slider members
49 and 50 of inverted hatlike cross section for moving contact with
the supporting rollers 7 and 40 included in the second and first
conveyors 1 and 2 respectively. The lower ends of the slider
members 49 and 50 and those of the rails 47 and 48 are all included
in the same plane and, where any two of these members or rails
intersect each other, one of them is partially cut away at the
intersection to render them flush with each other. On the opposite
sides of the lugs 46, lugs 51 project downward from the loading
plate 44 with which pushers 33 on the two article discharging
chains 34 come into contact from outside. Although not shown, the
second conveyor 2 is likewise equipped at its front end with
pusher-carrying chains substantially equivalent to the chains 34 in
the first conveyor 1. Accordingly, downwardly projecting lugs 52
are similarly provided on the opposite sides of the lugs 45 so that
the pushers will contact with the lugs 52 from outside. The lower
ends of the lugs 51 and 52 are positioned in the same plane as the
outer bottom surfaces of the rails 47 and 48 and those of the
slider members 49 and 50. A pair of triangular reinforcing plates
53 bear against each of the lugs 51 and 52 and are fixed to the
under surface of the loading plate 44. The lugs 45, 46, 51 and 52
are symmetrically disposed in pairs so as to render the pallet
usable reversibly with respect to the opposite sides. Workpieces or
the like to be conveyed are placed on such pallet and are sent
forward on the conveyors 1 and 2.
FIGS. 9 and 10 illustrate the operation to accumulate articles
which are being conveyed continuously on the conveyor at
predetermined specing. At a specified portion of the second
conveyor 2, an unillustrated stopper is disposed which is movable
into or retractable from the path of movement of the upper end of
the lever 26. When the articles are to be accumulated, the stopper
is advanced into the path of movement. As will be stated later, the
stopper may be a cam or like member which is movable into or
removable from the path of travel of the roller 22 on the pusher
21. The stopper thus positioned pushes down the lever 26 in front
of the pusher 21 in engagement with the front lug 45 of a first
advancing article P.sub.1, causing its rear projection 29 to
descend. Consequently, the link 30 acts to depress the front
projection 24 of the pusher 21. This movement tilts the pusher 21,
disengaging the upper projection 21a thereof from the lug 45 of the
article P.sub.1, whereby the first article P.sub.1 is brought to a
halt. By the "first article" herein referred to is meant one of a
number of travelling articles which is to be stopped first. When
the first article P.sub.1 is thus stopped, a second article P.sub.2
and the succeeding articles are still travelling with the drive
chain 11 (see FIG. 9). The lever 26 for the pusher 21 engaging the
article P.sub.2 then comes into contact with the preceding first
article P.sub.1, which in turn acts on the lever 26 like the
aforementioned stopper. The resulting inclination of the lever 26
pushes down the pusher 21 out of engagement with the second article
P.sub.2, which therefore comes to a halt adjacent the first article
P.sub.1 in accumulated state. The roller 27 on the lever 26
advances in rolling contact with the under surface of rail 47 on
the first article P.sub.1. The upper projection 21a of the pusher
21, located at a lower level than the roller 27 when in tilted
position, will not come into contact with the first article P.sub.1
(see FIG. 10). Inasmuch as the stopper is disposed in front of the
front end of the first article P.sub.1, the lever 26 which has
moved past the front end remains inclined until it passes by the
stopper, retaining the pusher 21 also in its tilted position.
Accordingly the pusher 21 will not rises to engage the lug 45 of
the article P.sub.1 as shown in FIG. 9 upon the lever 26 moving
past the front end of the article P.sub.1. As the drive chain 11
travels forward, a third article and the following articles are
brought into halt one after another, each in end-to-end contact
with the preceding article in accumulated fashion.
To move a group of stopped articles P again, the stopper is
retracted from the path of movement of the lever 26. This permits
the lever 26 advancing from behind to rise under gravity, the
moment when it passes by the lug 45 of the first article P.sub.1
since it is freed from the pressure of the article P.sub.1 at that
moment. Consequently, the pusher 21 is raised under gravity and by
the upward movement of rear projection 29 of the lever 26 which is
transmitted through the link 30 to the front projection 24 of the
pusher 21. Thus the upper projection 21a of the pusher 21 engages
the lug 45 of the article P.sub.1 to advance the article P.sub.1.
It will be apparent that as the first article P.sub.1 moves forward
which has been serving as a stopper, the succeeding pushers 21 come
into engagement with the second and following articles P.sub.2 one
after another, respectively, to thereby bring the articles P.sub.1
into travel.
The articles P are carried on the second conveyor 2 serving as a
main conveyor, each with its length positioned longitudinally of
the conveyor 2. To transfer the articles P sent forward by the
first conveyor 1 which is a branch conveyor onto the second
conveyor 2 without changing the orientation of the articles P, the
articles P are conveyed on the first conveyor 1, each with its
width positioned longitudinally of the conveyor. The articles P
thus positioned on the first conveyor 1 are transferred onto the
second conveyor 2 by pushing means 54 and receiving and
transferring means 55 shown in FIGS. 1 to 3. The pushing means 54
comprises inner frames 56 disposed in the front portion of the
first conveyor 1, a rod 58 supported by bearings 57 on the frames
56 and extending transversely of the frames 56, pivotal bars 60
fixed to the opposite ends of the rod 58 respectively and each
extending upward to carry a roller 59 at its upper end, an ear 61
extending downward from the midportion of the rod 58, and a
hydraulic cylinder 65 having a piston rod 62 whose end is pivoted
to the ear 61 and a base end 63 whose ear is pivoted to an ear
attached to a support 64 for frames 56. The receiving and
transferring means 55 comprises base frames 66 included in the
second conveyor 2 and disposed forwardly of the first conveyor 1,
two rods 68 spaced apart from each other by a specified distance
and extending transversely of the base frames 66, the rods 68 being
supported by bearings 67 on base frames 66, pivotal bars 70 fixed
to each of the rods 68 proximate to its opposite ends and each
extending upward to carry a roller 69 at the upper end thereof,
substantially L-shaped downwardly extending levers 71 each fixed to
one end of each rod 68 which end extends outward from the bearing
67, a pair of links 72 connecting the two levers 71, and a
hydraulic cylinder 75 having a piston rod 73 whose distal end is
pivoted to lengthwise midportion of one of the levers 71 and a base
end 74 whose ear is pivoted to a support member on the base frame
66.
When articles P are transferred from the first conveyor 1 onto the
second conveyor 2, the pushers 21 and levers 26 on the second
conveyor 2 positioned at a higher level than the rollers 7 would
impede the advance of the articles. FIGS. 1 and 3 show cam means 76
for bringing the pushers 21 and levers 26 down to a level lower
than the upper ends of the rollers 7. The cam means 76 comprises a
barlike cam 77 disposed forwardly of the first conveyor 1 in
opposing relation to the front end thereof and positioned under the
drive chain 11 of the second conveyor 2 and pairs of elongated
parallel links 78 having upper ends pivotally supporting the cam 77
and lower ends secured to the same rods 68 as the pivotal bars 70.
The cam 77 has a horizontal upper surface 77a longer than the width
of the first conveyor 1 and downwardly slanting surfaces 77b at its
opposite ends. Each pair of the parallel links 78 are positioned on
the opposite sides of the cam 77 to support the cam 77 at a
position close to each end of the cam.
When the piston rod 62 is extended by the operation of the
hydraulic cylinder 65, the pivotal bars 60 of the pushing means 54
are inclined rearward, bringing the rollers 59 at their upper ends
to a level lower than the upper ends of the supporting rollers 40
as shown in the solid line in FIG. 2. When retracted, the piston
rod 62 turns the pivotal bars 60 to upright position, bringing the
rollers 59 to horizontal position above the upper ends of the
supporting rollers 40 as indicated in the dot-and-dash line in FIG.
2. The article P carried on the first conveyor 1 is sent toward the
second conveyor 2 by the discharging chains 34, more specifically
by the rollers 42 on the upper ends of the pushers 33 mounted on
the chains 34. At this time the longitudinal center line of the
article P must be brought into alignment with the center line of
the second conveyor 2 correctly. In other words, the lugs 45 at the
widthwise midportion of the article P must be positioned in the
path of travel of the pushers 21 on the drive chain 11. Otherwise,
it would be impossible for the pusher 21 to engage the article P to
advance the same. The pushing means 54 assures accuracy in bringing
the article P to the correct position. Thus when the pivotal bars
60 turn in a counterclockwise direction in FIG. 2 from inclined
position to upright position, namely when the rollers 59 on the
upper ends thereof shift from lower position to elevated position,
the article P which has been pushed forward by the pushers 33 as
already described is further pushed by the rollers 59 on its rear
side, the rollers 59 thus acting to place the article P correctly
on the second conveyor 2 when brought to their elevated position.
Since the first conveyor 1 is employed as a branch conveyor, the
articles P are usually conveyed predominantly on the second
conveyor 2. Since the opening 43 is formed at the junction of the
first conveyor 1 and the second conveyor 2, the article P which has
been guided by the guide rails 13 may possibly be guided improperly
and displaced sidewise at this position. To avoid this, the pivotal
bars 60 which are normally in upright position permit the
horizontally positioned rollers 59 on their upper ends to guide one
side of the article P when the article passes the opening portion
43. Further only when the article P is to be transferred from the
first conveyor 1 onto the second conveyor 2, a limit switch and
photoelectric tube or like detecting means detect that the article
is brought close to the front end of the first conveyor 1 so that
the pivotal bars 60 are inclined rearward temporarily before the
article P is positioned above the pushing means 54. Upon lapse of a
predetermined period of time, a timer actuates the pivotal bars 60
into the foregoing operation to send out the article P.
The hydraulic cylinder 75 operates to extend the piston rod 73,
which in turn brings the pivotal bars 70 of the receiving and
transferring means 55 to substantially upright position as
indicated in the solid line in FIG. 3, thereby permitting the
rollers 69 on their upper ends to assume a substantially vertical
posture. In this state, the support pins of the rollers 69 are at
right angles to those of the supporting rollers 7 on the second
conveyor 2, and the rollers 69 are in alignment with the supporting
rollers 40 on the first conveyor 1. Furthermore, the supporting
rollers 69 are positioned slightly above the supporting rollers 7
but at the same level as the supporting rollers 40 of the first
conveyor 1. When retracted, the piston rod 73 inclines the pivotal
bars 70 and brings the rollers 69 to a level lower than the
supporting rollers 7. Before the article P is transferred from the
first conveyor 1 onto the second conveyor 2, the four pivotal bars
70 are raised. Subsequently, the rollers 69 on their upper ends
receive the article P sent out onto the second conveyor 2. The
pivotal bars 70 are then turned in a counterclockwise direction in
FIG. 3 to inclined position, namely the rollers 69 are brought from
elevated position to lowered position to place the article P on the
rollers 69 onto the supporting rollers 7.
As already described, it is required that at the junction of the
first and second conveyors 1 and 2 the pusher 21 and lever 26 on
the drive chain 11 should not project upward from the level of the
supporting rollers 7 during the foregoing article transferring
operation. This requirement is fulfilled by the cam means 76 shown
in FIGS. 1 to 3 and FIGS. 11 and 12.
The parallel links 78 of the cam means 76 are supported on the same
rods as the pivotal bars 70 and are pivotally movable in
synchronism therewith. When the parallel links 78 are upright as
indicated in the solid line in FIG. 3, the cam is positioned close
to the drive chain 11 and is located in the path of movement of the
roller 22 at the lower end of the pusher 21, whereas when the
parallel links 78 are in their inclined position as indicated in
the dot-and-dash line in the same figure, the cam 77 is remote from
the drive chain and is positioned below the path of movement of the
roller 22. Normally, the cam 77 is in its lowered position along
with the rollers 69 of the receiving and transferring means 55. The
article P on the second conveyor 2 therefore moves along at the
junction of the first and second conveyor 1 and 2, free of
interference with the cam 77 and the rollers 69 (see FIG. 11). When
the article P is to be transferred from the first conveyor 1 onto
the second conveyor 2 as described above, the cam 77 and rollers 69
are brought up to elevated positions at the same time.
Consequently, the roller 22 on the pusher 21 rolls up along the
rear slanting surface 77b of the cam 77. This movement turns the
pusher 21 about the pivot 20, causing the lower projection 21b
thereof to rise while conversely lowering its upper projection 21a.
As a result, the tilting movement of the pusher 21 inclines the
lever 26 to which the pusher is linked as at 30. While the roller
22 is rolling along on the horizontal upper surface 77a of the cam
77 at its elevated position, the pusher 21 and lever 26 remain
inclined below the upper ends of the support rollers 7. When the
article P sent out from the first conveyor 1 and supported on the
rollers 69 is placed onto the supporting rollers 7 by virtue of
inclination of the pivotal bars 70 of the receiving and
transferring means 55, the cam 77 descends simultaneously,
permitting the pusher 21 to rise under gravity. Thus the pusher
advancing from behind the article P now stopped on the supporting
rollers 7 comes into engagement therewith to advance the article.
When the article P has moved past the junction of the first and
second conveyors 1 and 2, the cam 77 and rollers 69 are shifted to
their elevated positions to incline the pusher 21 and lever 26. At
the same time, another article P subsequently discharged from the
first conveyor 1 onto the second conveyor 2 is received by the
rollers 69. Through the repetition of the same operation, the
articles P sent forward on the first conveyor 1 are transferred
onto the second conveyor 2 one after another.
During the transfer operation described, there arises a need to
stop a group of articles before the junction of the first and
second conveyors 1 and 2 while the articles are being sent forward
on the second conveyor 2. To this end a stopper may be provided at
the position before the junction. It will be apparent that in the
same manner as described with reference to FIGS. 9 and 10, the
advancing articles will then be brought to a halt one after another
in accumulated fashion. Even in the absence of such stopper, the
articles can be stopped before the junction by the cam 77 as
apparent from FIG. 12. In this case, however, the spacing between
the pushers 21 must be taken into consideration.
The means for receiving and transferring the articles P may
alternatively comprise an endless drive chain which is positioned
in the second conveyor 2 transversely thereof in alignment with the
first conveyor 1 or drive rollers having axes positioned
longitudinally of the second conveyor 2, such alternative means
being rendered movable upward and downward with respect to the
upper ends of the supporting rollers 7.
The conveyor of the accumulation type shown in the foregoing
embodiment is a novel conveyor for which a separate patent
application has already been filed. If a known conveyor of the
accumulation type is used which is adapted to push articles from
behind, special lugs can be dispensed with, so that the article to
be conveyed need not be a pallet as herein shown specifically.
The present invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The presently disclosed embodiments are therefore to be
considered in all respects as illustrative and not restrictive, the
scope of the invention being indicated by the appended claims
rather than by the foregoing description, and all changes which
come within the meaning and range of equivalency of the claims are
therefore intended to be embraced therein.
* * * * *