U.S. patent number 3,921,790 [Application Number 05/351,924] was granted by the patent office on 1975-11-25 for conveying of cigarettes and other rod-like articles.
This patent grant is currently assigned to Molins Limited. Invention is credited to Peter Alec Clarke, Dennis Hinchcliffe.
United States Patent |
3,921,790 |
Hinchcliffe , et
al. |
November 25, 1975 |
Conveying of cigarettes and other rod-like articles
Abstract
Tray filling or unloading machine includes a junction zone from
which cigarettes pass into a delivery channel (e.g. a chute); means
for delivering articles into the junction zone; and a reservoir
comprising a conveyor for carrying a stack of articles into or from
the junction zone as required, the speeds of the conveyor while
moving in opposite directions being different, so that the
reservoir absorbs or discharges articles at the full rate at which
the machine is capable of handling articles while each tray is
being replaced by the next, and discharges or absorbs the articles
at other times at a slower speed.
Inventors: |
Hinchcliffe; Dennis (London,
EN), Clarke; Peter Alec (London, EN) |
Assignee: |
Molins Limited (London,
EN)
|
Family
ID: |
10113668 |
Appl.
No.: |
05/351,924 |
Filed: |
April 17, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Apr 21, 1972 [UK] |
|
|
18510/72 |
|
Current U.S.
Class: |
414/403;
198/347.3; 198/601; 198/573; 198/577 |
Current CPC
Class: |
A24C
5/352 (20130101) |
Current International
Class: |
A24C
5/352 (20060101); A24C 5/00 (20060101); B65G
043/08 () |
Field of
Search: |
;198/76,69,37,2C
;214/302 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Blunk; Evon C.
Assistant Examiner: Watts; Douglas D.
Attorney, Agent or Firm: Smith, Jr.; John C.
Claims
We claim:
1. A cigarette tray handling machine including means defining a
junction zone; means defining a delivery channel for receiving a
stack of cigarettes from said junction zone, said delivery channel
having a width sufficient to accommodate a plurality of cigarettes
in side-by-side relation; means for delivering cigarettes into the
junction zone; and a reservoir comprising a conveyor for carrying a
stack of cigarettes into or from the junction zone as required, and
means for continuously driving the conveyor at a first
predetermined speed while moving in one direction and at a second
predetermined speed while moving in the opposite direction, so that
the reservoir absorbs or discharges cigarettes at the full rate at
which the machine is capable of handling cigarettes while each tray
is being replaced by the next tray, and discharges or absorbs the
cigarettes at other times at a slower speed.
2. A machine according to claim 1 further comprising sensor means
for detecting the level of cigarettes in said junction zone and to
control movement of the reservoir conveyor in both directions to
maintain the level of cigarettes in the junction zone within
predetermined limits.
3. A machine according to claim 1 in which the delivery channel
extends downwards from the junction zone, and in which the
reservoir conveyor extends substantially horizontally from the
junction zone.
4. A machine according to claim 3 including a top band which is
parallel to the reservoir conveyor to confine the upper surface of
the stack of cigarettes in the reservoir and means for concurrently
driving said top band in the same direction and at the same speed
as said reservoir conveyor.
5. A machine according to claim 1 wherein said means for delivering
cigarettes into the junction zone comprises parallel bands arranged
to grip the cigarettes in a single row between them and deliver the
single row of cigarettes into the junction zone.
6. A cigarette tray filling machine including means defining a
junction means; means defining a delivery channel for receiving a
stack of cigarettes from said junction zone, said delivery channel
having a width sufficient to accommodate a plurality of cigarettes
in side-by-side relation; means for delivering cigarettes into the
junction zone; and a reservoir comprising a conveyor for carrying a
stack of cigarettes into or from the junction zone as required, and
means to continuously drive the conveyor in a first direction at a
first, high predetermined speed from a substantially predetermined
starting position, whereby the reservoir absorbs cigarettes at the
full rate at which the machine is capable of receiving cigarettes
while each tray is being replaced by the next tray, and in the
opposite direction at other times at a second, slower,
predetermined speed, whereby the reservoir conveyor gradually
returns to the starting position from which it can again begin to
receive cigarettes at said full rate for a predetermined
period.
7. A machine according to claim 6 wherein said means for driving
the conveyor comprises reversible drive means for selectively
driving said conveyor in said first and opposite directions and
different-ratio transmission means for selectively driving said
conveyor at said first and second predetermined speeds.
8. A machine according to claim 7 further comprising means for
exchanging trays.
9. A machine according to claim 6 wherein said means defining a
delivery channel comprises wall means defining a channel below and
communicating with said junction zone, said wall means including
two walls at opposite sides of said channel which diverge in the
downward direction from said junction zone to a point where the
distance between said two walls is substantially the same as the
width of a tray, and a flow divider positioned in said channel
between said diverging walls forming two downwardly diverging
channels, each defined by said flow divider and one of said
diverging walls, whereby the stream of cigarettes moving downwardly
from said junction zone is divided into two narrower streams by
said flow divider, said narrower streams flowing through said
respective downwardly diverging channels and merging to form a
single wide stack of cigarettes in said channel below said flow
divider.
10. A machine according to claim 9 wherein said flow divider
comprises a longitudinal member extending substantially parallel to
said two diverging walls, said member including two further
diverging walls, each said further diverging wall defining with one
of said diverging walls one of said diverging channels and
rotatably driven means along the lower edge of each of said further
diverging walls for directing cigarettes from said diverging
channels beneath said flow divider to form said wide stack of
cigarettes.
11. A cigarette tray unloading machine including means defining a
junction zone; means defining a delivery channel for receiving a
stack of cigarettes from said trays, said delivery channel having a
width sufficient to accommodate a plurality of cigarettes in
side-by-side relation; means for delivering cigarettes into the
junction zone; and a reservoir comprising a conveyor for carrying a
stack of cigarettes into or from the junction zone as required, and
means to continuously drive the conveyor in a first direction at a
first, high predetermined speed from a substantially predetermined
starting position, whereby the reservoir discharges cigarettes at
the full rate at which the machine is capable of delivering
cigarettes while each tray is being replaced by the next tray, and
in the opposite direction at other times at a second, slower,
predetermined speed, whereby the reservoir conveyor gradually
returns to the starting position from which it can again begin to
discharge cigarettes at said full rate for a predetermined
period.
12. A machine according to claim 11 wherein said means for driving
the conveyor comprises reversible drive means for selectively
driving said conveyor in said first and opposite directions and
different-ratio transmission means for selectively driving said
conveyor at said first and second predetermined speeds.
13. A machine according to claim 12 further comprising means for
exchanging trays.
14. A machine for loading cigarettes and other rod-like articles
into a sequence of trays comprising:
a. means defining a junction zone for containing said articles at a
substantially constant rate,
b. means for delivering said articles into said junction zone,
c. means defining a delivery channel for receiving a stack of said
articles from said junction zone and delivering said articles to
said trays, said delivery channel having a width sufficient to
accommodate a plurality of cigarettes in side-by-side relation,
and
d. a reservoir communicating with said junction zone and comprising
a conveyor for carrying a stack of said articles into and from said
junction zone and means for continuously driving the conveyor in a
direction away from said junction zone at a fast predetermined
speed sufficient to absorb said articles at the full rate at which
the machine is capable of handling said articles while each tray is
being replaced by the next tray and for driving the conveyor in the
opposite direction towards said junction zone at a slower
predetermined speed to discharge said absorbed articles into said
junction zone while each tray is being filled.
15. A machine according to claim 14 further comprising sensor means
for detecting the level of cigarettes in said junction zone and to
control movement of the reservoir conveyor in both directions to
maintain the level of cigarettes in the junction zone within
predetermined limits.
16. A machine according to claim 14 wherein said means defining a
delivery channel comprises wall means defining a channel below and
communicating with said junction zone, said wall means including
two walls at opposite sides of said channel which diverge in the
downward direction from said junction zone to a point where the
distance between said two walls is substantially the same as the
width of a tray, and a flow divider positioned in said channel
between said diverging walls forming two downwardly diverging
channels, each defined by said flow divider and one of said
diverging walls, whereby the stream of articles moving downwardly
from said junction zone is divided into two narrower streams by
said flow divider, said narrower streams flowing through said
respective downwardly diverging channels and merging to form a
single wide stack of articles in said channel below said flow
divider.
17. A machine according to claim 16 wherein said flow divider
comprises a longitudinal member extending substantially parallel to
said two diverging walls, said member including two further
diverging walls, each said further diverging wall defining with one
of said diverging walls one of said diverging channels and
rotatably driven means along the lower edge of each of said further
diverging walls for directing articles from said diverging channels
beneath said flow divider to form said wide stack of articles.
18. A machine for unloading cigarettes and other rod-like articles
from a sequence of trays comprising:
a. means defining a junction zone for containing said articles,
b. means defining a delivery channel for receiving a stack of said
articles from said trays and delivering said articles to said
junction zone, said delivery channel having a width sufficient to
accommodate a plurality of cigarettes in side-by-side relation,
c. means for discharging said articles from said junction zone at a
substantially constant rate, and
d. a reservoir communicating with said junction zone and comprising
a conveyor for carrying a stack of said articles into and from said
junction zone and means for continuously driving said conveyor in a
direction away from said junction zone at a slow predetermined
speed sufficient to absorb some of said articles from said junction
zone while each tray is being discharged into said delivery channel
and for driving the conveyor in the opposite direction towards said
junction zone at a faster predetermined speed to discharge said
absorbed articles into said junction zone while each tray is being
replaced by the next tray.
19. A machine according to claim 18 further comprising sensor means
for detecting the level of cigarettes in said junction zone and to
control movement of the reservoir conveyor in both directions to
maintain the level of cigarettes in the junction zone with
predetermined limits.
20. A machine according to claim 1 wherein said means for driving
the conveyor comprises reversible drive means for selectively
driving said conveyor in said one and opposite directions and
different-ratio transmission means for selectively driving said
conveyor at said first and second predetermined speeds.
21. A machine according to claim 20 further comprising means for
exchanging trays.
22. A cigarette tray handling machine including means defining a
junction zone; means defining a delivery channel for receiving
cigarettes from said junction zone; means for delivering cigarettes
into the junction zone; a reservoir comprising a conveyor for
carrying a stack of cigarettes into or from the junction zone as
required; and means for driving the conveyor, comprising a
reversible motor, different-ratio transmissions, and a plurality of
unidirectional clutches to selectively drive said reservoir
conveyor at different predetermined speeds while moving
respectively in opposite directions; so that the reservoir absorbs
or discharges cigarettes at the full rate at which the machine is
capable of handling cigarettes while each tray is being replaced by
the next tray, and discharges or absorbs the cigarettes at other
times at a slower speed.
23. A machine according to claim 22 in which the delivery channel
extends downwards from the junction zone, and in which the
reservoir conveyor extends substantially horizontally from the
junction zone.
24. A machine according to claim 23 including a top band which is
parallel to the reservoir conveyor to confine the upper surface of
the stack of cigarettes in the reservoir and means for concurrently
driving said top band in the same direction and at the same speed
as said reservoir conveyor.
25. A machine according to claim 22 further comprising sensing
means to detect the level of cigarettes above said junction zone
and to control movement of the reservoir conveyor in both
directions to maintain the level of cigarettes in the junction zone
between predetermined limits.
26. A machine according to claim 22 in which said means for
delivering cigarettes into the junction zone comprises parallel
bands arranged to grip the cigarettes in a single row between them
and deliver the single row of cigarettes into the junction
zone.
27. A machine according to claim 22 further comprising means for
exchanging trays.
28. A cigarette tray filling machine including means defining a
junction zone; means defining a delivery channel adapted to receive
a stack of cigarettes from said junction zone and carry the stack
towards a tray; means for delivering cigarettes into the junction
zone; a reservoir comprising a conveyor for carrying a stack of
cigarettes into or from the junction zone as required; and driving
means for continuously driving the conveyor in a direction away
from the junction zone at a faster speed sufficient to absorb
cigarettes at the full rate at which the machine is capable of
receiving cigarettes while each tray is being replaced by the next
tray, and towards the junction zone at other times at a slower
speed so that the reservoir conveyor gradually returns to its
starting position from which it can again begin to receive
cigarettes at said full rate when the next tray is changed.
29. A machine according to claim 28 wherein said means for driving
the conveyor comprises reversible drive means for selectively
driving said conveyor both away from the junction zone and towards
the junction zone and different-ratio transmission means for
selectively driving said conveyor at said faster speed and said
slower speed respectively.
30. A cigarette tray filling machine according to claim 28 in which
said driving means is adapted to drive the reservoir conveyor at
different predetermined speeds in different directions.
31. A cigarette tray filling machine according to claim 28 arranged
to deliver cigarettes as a wide stack, corresponding to the width
of a tray, in a downward direction into the tray, the delivery
channel including wall means defining a channel below and
communicating with said junction zone, said wall means including
two walls at opposite sides of said delivery channel which diverge
in the downward direction from said junction zone to a point where
the distance between said two walls is substantially the same as
the width of a tray, and a flow divider positioned in said channel
between said diverging walls forming two downwardly diverging
channels, each defined by said flow divider and one of said
diverging walls, whereby the stream of cigarettes moving downwardly
from said junction zone is divided into two narrower streams by
said flow divider, said narrower streams flowing through said
respective downwardly diverging channels and merging to form a
single wide stack of cigarettes in said channel below said flow
divider.
32. A cigarette tray filling machine according to claim 31 in which
said flow divider comprises a longitudinal member extending
substantially parallel to said two diverging walls, said member
including two further diverging walls, each said further diverging
wall defining with one of said diverging walls one of said
diverging channels and rotatably driven means along the lower edge
of each of said further diverging walls for directing cigarettes
from said diverging channels beneath said flow divider to form said
wide stack of cigarettes.
33. A cigarette tray filling machine according to claim 28
including sensing means to sense the level of cigarettes in the
junction zone, said driving means being controlled in response to a
signal derived from said sensing means.
34. A cigarette tray unloading machine including means defining a
junction zone, means defining a delivery channel for receiving a
stack of cigarettes from the junction zone, said delivery channel
having a width sufficient to accommodate a plurality of cigarettes
in side-by-side relation; means defining an input channel having a
width of several cigarette diameters and adapted to deliver a stack
of cigarettes into the junction zone from the trays; a reservoir
comprising a conveyor for carrying a stack of cigarettes into or
from the junction zone as required; and driving means for
continuously driving the conveyor in a direction towards the
junction zone at a high speed sufficient to discharge cigarettes
from the reservoir at the full rate at which the machine is capable
of delivering cigarettes while each tray is being replaced by the
next tray, and away from the junction zone at other times at a
slower speed so that the reservoir gradually absorbs cigarettes so
that it can again discharge cigarettes at the full rate when the
next tray is changed.
35. A machine according to claim 34 wherein said means for driving
the conveyor comprises reversible drive means for selectively
driving said conveyor both towards the junction zone and away from
the junction zone and different-ratio transmission means for
selectively driving said conveyor at both said high speed and said
slower speed respectively.
36. A cigarette tray unloading machine according to claim 34 in
which said driving means is adapted to drive the reservoir conveyor
at different predetermined speeds in different directions.
37. A cigarette tray unloading machine according to claim 34 in
which said input channel, said reservoir, and said delivery channel
meet at said junction zone to form a T-shaped junction having two
arms extending substantially in line and the third arm
substantially at right-angles to the two in-line arms.
38. A cigarette tray unloading machine according to claim 37 in
which the two in-line arms of the T-junction are substantially
horizontal.
39. A cigarette tray unloading machine according to claim 38 in
which the two horizontal arms of the T-junction are the input
channel and the reservoir.
40. A cigarette tray unloading machine according to claim 38 in
which the input channel, the delivery channel, and the reservoir
are all adapted to accommodate stacks of substantially the same
height.
41. A cigarette tray unloading machine according to claim 34
including sensing means to sense the level of cigarettes in the
junction zone, said driving means being controlled in response to a
signal derived from said sensing means.
Description
This invention is particularly concerned with tray systems for
cigarettes, but can also be used in connection with similar
rod-like articles, for example cigarette filter rods and smokable
rods other than cigarettes. The term "cigarette" will for
convenience be used throughout this specification and is intended
to include other similar rod-like articles.
Tray systems for cigarettes commonly involve occasional temporary
stoppage of the flow of the cigarettes while each tray is being
replaced by the next tray. For example, in a tray filling machine
the delivery of cigarettes to the filling position stops while each
full tray is being replaced by the next tray ready for filling; on
the other hand, in a tray unloading machine (i.e. for emptying
trays) it may be desirable (as described for example in U.S. Pat.
No. 3,759,408) to stop withdrawing cigarettes in the region of the
unloading hopper while each empty tray is being replaced by the
next full tray to reduce the distance through which the cigarettes
from the full tray must drop onto the surface of the cigarettes
remaining from the previous tray.
According to a first aspect of the present invention a tray filling
or unloading machine includes a junction zone from which cigarettes
pass into a delivery channel (e.g. a chute); means for delivering
articles into the junction zones; and a reservoir comprising a
conveyor for carrying a stack of articles into or from the junction
zone as required, the speeds of the conveyor while moving in
opposite directions being different, so that the reservoir absorbs
or discharges articles at the full rate at which the machine is
capable of handling articles while each tray is being replaced by
the next, and discharges or absorbs the articles at other times at
a slower speed. The delivery channel and reservoir conveyor may
extend respectively downwards and substantially horizontally from
the junction zone. Alternatively, the reservoir may comprise two
vertically movable bands extending downwards from the junction zone
and carrying a wall forming the bottom end of the reservoir, and
the delivery channel may extend horizontally from the junction
zone; such an arrangement is described in patent application Ser.
No. 408,256 filed Oct. 23, 1973.
In the case of a tray filling machine, while each full tray is
being replaced by an empty tray, the reservoir receives all the
articles which are delivered into the junction zone, for example by
a cigarette or filter rod making machine, for which purpose the
reservoir conveyor moves at a relatively high speed away from the
junction zone. Then while the next tray is being filled, the
reservoir conveyor moves relatively slowly towards the junction
zone so that the reservoir is substantially empty by the time the
tray is full, so as to be ready to receive the full flow of
articles into the junction zone while the next tray change is
taking place.
In the case of a tray-unloading machine, the articles are
preferably carried horizontally out of each tray in turn on a
delivery conveyor, preferably in stack formation, and are delivered
by the delivery conveyor to a junction zone above a chute. While
the delivery conveyor is delivering articles into the junction
zone, the reservoir conveyor moves slowly away from the junction at
a speed such that the reservoir is substantially full by the time
the tray has emptied. Then while the empty tray is being replaced
by a full tray (during which period the delivery conveyor is
stopped) the reservoir conveyor moves at a relatively fast speed
towards the junction zone to deliver articles at the rate at which
the articles are required to pass down the chute.
Preferably the movement of the reservoir conveyor in both
directions is controlled by a sensor (for example, a pivoted plate)
above the junction zone to maintain the level of articless in the
junction zone within predetermined limits.
According to another aspect of this invention, a tray filling
machine delivers the cigarettes as a wide stack (corresponding to
the width of a tray) moving downwards into the tray, the wide stack
being formed by delivering the cigarettes into a junction zone from
which the cigarettes are fed along two downwardly diverging
channels from the lower outlet ends of which the cigarettes of each
channel are spread horizontally, for example by rollers, to form
the wide stack. There is preferably a reservoir communicating with
the junction zone in accordance with the first aspect of this
invention.
Examples of arrangements according to the invention are shown in
the accompanying drawings wherein:
FIG. 1 shows a tray filling system according to the invention;
FIG. 2 is a diagrammatic illustration of a drive system suitable
for a tray filling system as shown in FIG. 1; and
FIG. 3 shows diagrammatically a tray unloader according to the
invention.
As shown in FIG. 1 a single row of cigarettes 2 is fed sideways
between delivery bands 4 and 6 which move along a curved path
defined by a fixed member 8 in contact with the band 6. Tension in
the bands (and particularly the band 4) results in the cigarettes
being gripped between the bands so that they can be fed firmly into
a junction zone 10. Above this junction zone there is a sensor
comprising intermeshing arms 12 and 14 which are pivoted at 12A and
14A so as to be able to move up and down in response to the
pressure of cigarettes in the junction zone 10.
The two sensor arms may be linked by a lost-motion linkage to a
common conveyor control mechanism, basically as described in U.S.
Pat. No. 3,561,585 dated Feb. 9, 1971. Alternatively, in a
preferred arrangement each arm may be arranged to operate one
switch when it reaches a lower limit (i.e. approximately as shown
in solid outline) and a second switch when it reaches an upper
limit (shown in dotted and dashed outline); the operation of the
sensor will be described further on.
Opposite the cigarette delivery bands 4 and 6 there is a reservoir
formed basically by a reversible conveyor band 16 to which is
attached an end wall 18. The reservoir also includes a top band 20
which is driven at the same speed and in the same direction as the
band 16 to define the top surface of the cigarette stack 21 in the
reservoir. The bands 16 and 20 pass round pulleys 16A, 16B, 20A,
20B as shown.
From the junction zone 10 the cigarettes pass downwards towards a
tray filling device (not shown) which is basically as described in
British patent specification No. 1,093,532 (U.S. Pat. No.
3,320,717). On the way down to the tray filling device, the flow of
cigarettes divides so as to pass downwards along opposite sides of
a flow divider 26. More specifically, the cigarettes pass downwards
as two similar stacks 28 and 30 which re-combine below the flow
divider 26 to form a wide stack corresponding to the width of the
trays to be filled. The flow divider 26 basically comprises three
walls 26A, 26B and 26C but includes also rollers 32 and 34 which
rotate in the directions shown to assist the cigarettes from the
stacks 28 and 30 to move inwards below the bottom wall 26C.
The top corner of the flow divider 26 is formed by a manually
rotatable roller 36 including a groove 36A. This roller 36 is used
to extract a cigarette from the general flow when necessary for
inspection, for which purpose the roller 36 is turned manually
through one revolution, so that a cigarette falls into the groove
36A and then drops out of the groove and onto the bottom wall 26C,
from which position it can readily be removed.
FIG. 1 just shows the top ends of two vertical walls 36 and 38
which confine the sides of the wide stack of cigarettes moving into
the tray filling device below.
While a tray is being filled, the reservoir conveyor bands move
slowly to the left so as to deliver cigarettes at a rate of 600 per
minute into the junction zone 10. The bands 4 and 6 deliver
cigarettes continuously from a cigarette making machine at a rate
of, for exmaple, 4,000 per minute. Thus a total of 4,600 cigarettes
per minute passes down from the junction zone and into the tray.
If, at any moment, both sensor arms reach their upper limits,
operation of both the upper limit switches results in the reservoir
bands stopping; as soon as both arms drop and thus release their
corresponding upper limit switches, the reservoir bands start
again, at the set speed, to deliver cigarettes into the junction
zone.
The capacity of the reservoir and the speed of its bands are such
that the end wall 18 is nearly at its extreme left position
(corresponding to the reservoir-empty condition) by the time the
tray is full. A master switch (not shown) is operated automatically
by a sensor when the tray is full, and this results in the full
tray being moved away and being replaced by an empty tray, during
which changeover period the reservoir bands are driven in the
opposite direction to draw cigarettes into the reservoir at a rate
of 4,000 per minute (i.e. equal to the rate at which cigarettes
continue to be delivered to the junction zone by the bands 4 and
6); the flow of cigarettes downwards from the junction zone is
stopped during the tray changeover period, for example as described
in British patent specification No. 1,093,532.
During the tray changeover period, if both sensor arms at any
moment reach their lower limiting positions, the operation of the
lower limit switches results in the reservoir bands stopping; the
bands start again when both arms rise and release their lower limit
switches.
The two speed drive of the reservoir bands (i.e. in opposite
directions) may be achieved as shown in FIG. 2. Similar gear wheels
40 and 42 are connected respectively to the pulleys 20A and 16A.
These gear wheels are interconnected via two idler gear wheels 44
and 46 (rotating about fixed axes) so that the two-pulleys always
rotate at the same speed but in opposite directions. Also connected
to the two pulleys 20A and 16A are two drive pulleys 44B and 46B
which are driven in the same direction via belts 48 and 50 from a
drive motor 52, the speeds of the two pulleys 44B and 46B
corresponding respectively to the slow and fast motions required of
the reservoir bands. The pulleys 44B and 46B drive the pulleys 20A
and 16A through unidirectional couplings 44A and 46A. Thus the
motor automatically transmits a fast drive to both bands when
running in one direction (clockwise) and a slow drive when running
in the opposite direction. It will be understood that the
unidirectional coupling 46A can only transmit a drive (fast) in a
clockwise direction, whereas the coupling 44A can only transmit a
drive (slow) in an anticlockwise direction.
In the event of the wall 18 reaching a position in which it
obscures a photo cell 22 (FIG. 1), a signal is derived from the
photo cell 22 to indicate that the reservoir is nearly full. In the
event of the wall 18 reaching its extreme right position, it
obscures a photo cell 24 which automatically stops the whole
machine.
The double arm sensor comprising the arms 12 and 14 may be replaced
by a single arm sensor resting more or less centrally on the
cigarettes in the junction zone 10.
FIG. 3 shows diagrammatically a tray unloader according to this
invention. Each tray 54 in turn is inverted at an unloading
position (as shown) so that a stack of cigarettes 56 can be carried
away by a conveyor 58 towards a junction zone above a chute 59
leading to a packing machine. While each tray is being unloaded, a
pair of reservoir conveyors 60 and 62 with an end wall 64 draw
cigarettes slowly from the junction zone, under the control of a
sensor 66, so that the reservoir is substantially full by the time
the tray has been emptied. Then while the empty tray is being
replaced by a full tray, the conveyors 60 and 62 move more rapidly
in the opposite direction (i.e. to the right) to deliver the
cigarettes back into the junction zone to continue the supply of
cigarettes to the packing machine through the chute 59.
* * * * *