U.S. patent number 3,782,069 [Application Number 05/198,167] was granted by the patent office on 1974-01-01 for bag closing machine with fluidic control system.
This patent grant is currently assigned to Dave Fischbein Manufacturing Co.. Invention is credited to Harold Fischbein, I. George Fischbein, Sam Shark.
United States Patent |
3,782,069 |
Fischbein , et al. |
January 1, 1974 |
BAG CLOSING MACHINE WITH FLUIDIC CONTROL SYSTEM
Abstract
An automatic bag closing machine for bags moving along a path
wherein tape is folded over and along the open ends of successively
arriving bags and then stitched to the bags to close them and the
tape clipped adjacent leading and trailing edges of each bag. A
fluidic control system with fluidic bag detection apparatus,
including sensors located at spaced intervals along the path of the
bags, actuates a sewing head when a bag is detected and continues
sewing head operation until the bag passes through the machine. The
fluidic control system also actuates a tape clipper assembly
including a moving knife, swinging the knife to clip the tape
adjacent the leading and trailing edges of the bag, the tape
clipper assembly further including a pair of alternating pistons
operatively connected to the knife to swing it across the path and
return, a first piston being actuated by the control system when
the detection apparatus signals the control system that the bag is
a predetermined distance upstream from the knife, and a second
piston being actuated to again swing and return the knife when the
bag is a predetermined distance downstream of the knife. The
invention also includes a method of closing taped bags with a bag
closing machine having a fluidic control system wherein bags
passing through the machine are detected by a fluidic bag detection
apparatus.
Inventors: |
Fischbein; I. George
(Minneapolis, MN), Fischbein; Harold (Edina, MN), Shark;
Sam (Minneapolis, MN) |
Assignee: |
Dave Fischbein Manufacturing
Co. (Minneapolis, MN)
|
Family
ID: |
22732259 |
Appl.
No.: |
05/198,167 |
Filed: |
November 12, 1971 |
Current U.S.
Class: |
53/67; 53/76;
53/136.5; 53/138.5; 83/371; 112/130; 112/272; 112/276 |
Current CPC
Class: |
D05B
13/02 (20130101); B65B 57/02 (20130101); B65B
51/07 (20130101); Y10T 83/543 (20150401); D05D
2303/02 (20130101); D05D 2305/12 (20130101) |
Current International
Class: |
B65B
57/02 (20060101); B65B 51/00 (20060101); B65B
51/07 (20060101); B65b 057/02 (); B65b
061/06 () |
Field of
Search: |
;53/14,67,75,76,139
;112/219B ;83/371 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGehee; Travis S.
Attorney, Agent or Firm: George F. Williamson et al.
Claims
We claim:
1. An automatic bag closing machine for bags moving along a path
wherein tape from a tape reel is folded over the open ends of
successively arriving bags and then stitched to the bags to close
the bags and the tape is clipped adjacent leading and trailing
edges of each bag, the machine using a shop supply of pressurized
air comprising:
a sewing head adjacent said path positioned to stitch the tape to
each successively arriving bag as it moves along said path;
a motor for driving said sewing head;
a wholly fluidic control system including a fluidic logic network,
a fluidic clutch interface valve and fluidic brake interface valve,
each said interface valve constructed to transmit pressurized air
through the valve when the valve is opened by a fluidic command
signal delivered to said valve and to otherwise prevent fluid flow
therethrough, each said interface valve being connected in fluid
flow relationship with said fluidic logic network so as to be
opened when a command signal is received by each said valve from
said logic network;
a pneumatically actuated clutch linking said motor and said sewing
head to transmit driving energy from said motor to said sewing head
and connected in fluid flow relationship with said clutch interface
valve to receive pressurized air from said clutch interface valve
when said clutch interface valve is open;
a pneumatically actuated brake positioned to stop operation of said
sewing head and connected in fluid flow relationship to said brake
interface valve to receive pressurized air from said brake valve
when said brake valve is open;
a pneumatically actuated, tape clipper assembly located along said
path, including a knife to sever the tape joining successfively
stitched bags, the tape clipper assembly being connected in fluid
flow relationship with the said wholly fluidic control system;
a fluidic bag detection apparatus, said detection apparatus
connected in fluid flow relationship to said fluidic logic circuit
of said fluidic control system and having a first sensor positioned
to detect a bag along said path at a first predetermined distance
upstream of the knife, a second sensor positioned at a second
predetermined distance upstream of the knife and a third sensor
positioned at a first predetermined distance downstream of the
knife, each said sensor providing a signal when a bag is detected
at any of said predetermined distances; and
said fluidic logic network including a plurality of pressure
sensitive fluidic switches and fluidic or circuits, said switches
operatively connected to receive signals from said sensors and in
response thereto fluidically actuate a plurality of said fluidic or
circuits to fluidically open said clutch interface valve thereby
engaging said clutch when a bag is detected by said first sensor at
said first predetermined distance upstream and thereafter retaining
said clutch interface valve in an open condition until the bag
passes said third sensor at said first predetermined distance
downstream, thereby maintaining the sewing head in operation while
the bag is detected by said third sensor at said first
predetermined distance downstream, a plurality of said fluidic or
circuits fluidically actuating said tape clipper assembly in
response to a said pressure sensitive switch receiving a signal
from said second sensor when a bag is detected at said second
predetermined distance upstream so as to sever the tape extending
in a downstream direction from the leading edge of the bag to
control tape length, a plurality of said fluidic or circuits
fluidically actuating said tape clipper assembly in response to a
said pressure sensitive switch receiving a signal from said
detection apparatus when the bag is no longer detected by said
third sensor at said first predetermined distance downstream from
said knife, thereby severing the tape adjacent the trailing edge of
the bag to separate the taped and stitched bag from a successive
bag, and a plurality of said fluidic or circuits fluidically
opening said brake interface valve to engage the brake in response
to no bag being detected by said sensors.
2. The combination according to claim 1 wherein said fluidic
control system includes a pressure regulator operatively connected
to the source of pressurized air to provide air at reduced pressure
for said fluidic logic network, and and each said plurality of
pressure sensitive fluidic switch has a control channel connected
in fluid flow relationship to said fluidic bag detection apparatus
and an inlet channel connected in fluid flow relationship to said
pressure regulator to receive air at reduced pressure
therefrom.
3. The combination according to claim 1 wherein each said fluidic
or circuit and said pressure-sensitive fluidic switch has a primary
outlet channel and a secondary outlet channel, each said secondary
outlet channel of said switches exhausting to the atmosphere and
each said primary outlet channel of said switches being connected
in fluid flow relationship to one of said fluidic or circuits.
4. The machine according to claim 1 wherein said tape clipper
assembly further includes:
first and second fluidic interface valves, each said interface
valve constructed to transmit pressurized air through the valve
when the valve is opened by a fluidic command signal delivered to
said valve and to otherwise prevent fluid flow therethrough, each
said interface valve being connected in fluid flow relationship
with said fluidic logic network so as to be opened when a command
signal is received by each said valve from said logic network;
first and second pistons; a housing including first and second
piston cylinders slideably mounting said first and second pistons,
respectively, said first and second cylinders connected in fluid
flow relationship to said first and second interface valves,
respectively, to deliver pressurized air to said cylinders from
said valves;
a crankshaft rotatably mounted in said housing for rotational
movement about its longitudinal axis;
a crank fixedly mounted on said crankshaft for movement with said
crankshaft;
first and second connecting rods pivotally mounted to said crank
and to said first and second pistons, respectively, said rods
transmitting longitudinal sliding piston movement along said
cylinder to said crank to produce limited rotational movement of
said crank and crankshaft about said crankshaft axis;
a knife shaft rotatably mounted in said housing for movement about
its longitudinal axis, said knife shaft mechanically coupled to
said crank for reciprocating swinging rotation about its
longitudinal axis in response to rotation of said crank and
crankshaft about said crankshaft axis; and
said knife being mounted adjacent an end of said knife shaft,
exterior to said housing, and positioned to swing across said path
as said knife shaft reciprocatingly rotates thereby severing the
tape extending from a bag.
5. An automatic bag closing machine using a supply of pressurized
air in which open top bags move along a path and have tape folded
over their open tops and attached thereto for closure, the tape
interconnecting successive bags and the continuous tape thereafter
being severed to separate one bag from the next comprising:
means for attaching the tape to each bag wherein the tape is folded
over the open top of each bag and attached to the bag;
a pneumatically actuated tape clipper assembly including a knife
positioned to sever the otherwise continuous length of tape
interconnecting successively closed bags;
a fluidic bag detection apparatus located along said path including
a first sensor positioned to detect a bag at a predetermined
distance from said knife, said apparatus producing a signal on
detection;
a wholly fluidic control system connected in fluid flow
relationship between said sensor and said clipper assembly to
receive said signal, said fluidic control system including a
fluidic logic network and a first interface valve constructed to
permit flow of pressurized air therethrough when actuated by said
fluidic logic network and otherwise to prevent air flow
therethrough, said first interface valve connected in fluid flow
relationship between the source of pressurized air and said tape
clipper assembly and also connected to said fluidic logic network
to permit flow of pressurized air through said first valve to said
tape clipper assembly when said first valve is opened by said
fluidic logic network, actuating said tape clipper assembly to
sever the tape interconnecting successive bags, said fluidic logic
network being responsive to a signal from said detection apparatus
to open said first interface valve when a bag is detected at the
predetermined distance from said knife by said first sensor.
6. The bag closing machine according to claim 5 wherein said bag
detection apparatus has a second sensor positioned to detect a bag
at a second predetermined distance from said knife to produce a
signal on detection of a bag at said second predetermined distance,
and said fluidic control system includes a second interface valve
constructed to permit fluid flow therethrough when fluidically
actuated by said fluidic logic network and to otherwise prevent
fluid flow therethrough, said second interface valve connected in
fluid flow relationship between said tape clipper assembly and the
source of pressurized air to said second interface valve to
energize said second valve, and connected in fluid flow
relationship to said fluidic logic network, said fluidic logic
network fluidically opening said second interface valve, in
response to said logic network receiving a signal from said
detection apparatus that a bag is detected by said second sensor at
said second predetermined distance, thereby energizing said tape
clipper assembly with pressurized air and severing the tape.
7. The machine according to claim 6 wherein said tape clipper
assembly includes first and second pneumatic pistons connected in
fluid flow relationship to the downstream side of said first and
second interface valves, respectively, to receive pressurized air
from said valves and said knife is swingably mounted along said
path of the bags to swing across said path from the starting
position clear of said path and return to the starting position in
response to a said piston being extended by pressurized air from a
said interface valve when a said interface valve is opened by said
fluidic logic network, said pistons being mechanically coupled to
said knife such that a stroke by said first piston in a single
direction swings said knife across said path of the bag and returns
it to starting position, said second piston then assuming a cocked
position from which it can, when actuated by pressurized air from
said second interface valve, deliver a stroke to swing said knife
across said path and return it to starting position, said first and
second pistons operating alternately as said first and second
interface valves, respectively, are opened by said fluidic control
system, thereby severing the tape extending from the edges of each
bag.
8. The bag closing machine according to claim 7 wherein said tape
clipper assembly further includes:
a housing including first and second piston cylinders slideably
mounting said first and second pistons, respectively, and connected
in fluid flow relationship to said first and second interface
valves, to respectively, receive pressurized air from said
valves;
a crankshaft rotatably mounted in said housing for rotational
movement about its longitudinal axis;
a crank fixed to said crankshaft for movement with said
crankshaft;
first and second connecting rods pivotally mounted to said crank
and to said first and second pistons, respectively, said rods
transmitting longitudinal piston movement to said crank to produce
limited rotational movement of said crank and crankshaft about said
crankshaft axis;
a knife shaft rotatably mounted in said housing for movement about
is longitudinal axis, said knife shaft mechanically coupled to said
crank for reciprocating swinging rotation about said knife shaft
longitudinal axis in response to rotation of said crank and
crankshaft about said crankshaft axis, said knife being mounted
adjacent an end of said knife shaft exterior to said housing and
swinging across said path as said knife shafe reciprocatingly
rotates thereby severing the tape extending from a bag.
9. The bag closing machine according to claim 8 and further
including a knife drive lever fixed to said knife shaft and having
a bifurcated cam extending outwardly therefrom and a drive link
with an end pivotally mounted to said crank and the remaining end
pivotally mounted to said bifurcated cam, said drive link
transmitting movement from said crank to said knife drive lever to
reciprocatingly rotate said knife shaft.
10. An automatic bag closing machine for bags moving along a path,
the machine using a shop supply of pressurized air comprising:
a sewing head adjacent said path positioned to stitch closed each
successively arriving bag as it moves along said path;
a motor for driving said sewing head;
a wholly fluidic control system including a fluidic logic network
and a clutch interface valve and brake interface valve, each said
interface valve constructed to transmit pressurized air through the
valve when the valve is opened by a fluidic command signal
delivered to said valve and to otherwise prevent fluid flow
therethrough, each said interface valve being connected in fluid
flow relationship with said fluidic logic network so as to be
opened when a command signal is received by each said valve from
said logic network;
a pneumatically actuated clutch linking said motor and said sewing
head to transmit driving energy from said motor to said sewing head
and connected in fluid flow relationship with said clutch interface
valve to receive pressurized air from said clutch valve when said
clutch valve is open;
a pneumatically actuated brake positioned to stop operation of said
sewing head and connected in fluid flow relationship to said brake
interface valve to receive pressurized air from said brake valve
when said brake valve is open;
a fluidic bag detection apparatus, said detection apparatus
connected in fluid flow relationship to said fluidic logic circuit
of said fluidic control system and have a first sensor positioned
to detect a bag along said path at a first predetermined distance
upstream of said sewing head and a second sensor positioned at a
first predetermined distance downstream of said sewing head, each
said sensor providing a signal when a bag is detected at any of
said predetermined distances; and
said fluidic logic network including a plurality of pressure
sensitive fluidic switches and fluidic or circuits, said switches
operatively connected to receive signals from said sensors and in
response thereto fluidically actuate a plurality of said fluidic or
circuits to fluidically open the clutch interface valve thereby
engaging said clutch when a bag is detected by said first sensor at
said first predetermined distance upstream and thereafter retaining
said clutch interface valve in an open condition until the bag
passes said second sensor at said first predetermined distance
downstream, thereby maintaining the sewing head in operation while
the bag is detected by said second sensor at said first
predetermined distance downstream, a plurality of said fluidic or
circuits fluidically opening said brake interface valve to engage
said brake in response to no bag being detected by said first and
second sensors.
Description
The purpose of the foregoing abstract is to enable the Patent
Office and the public generally, and especially the scientists,
engineers, or practitioners in the art who are not familiar with
patent or legal terms of phraseology, to determine quickly from a
cursory inspection the nature and essence of the technical
disclosure of the application. The abstract is neither intended to
define the invention of the application, which is measured by
claims, nor is it intended to be limiting as to the scope of the
invention in any way.
BACKGROUND OF THE INVENTION
The present invention relates to the field of industrial bag
closing machines and provides a bag closing apparatus utilizing a
fluidic control system and fluidic bag detection apparatus thereby
providing an extremely reliable, long lasting, trouble free machine
with a greatly reduced number of moving parts in the control
system.
Many industries require reliable, high speed bagging of their
products as they pass along power conveyors to the final shipping
point, and often thousands of bags per hour may pass through such a
bag closing machine. To insure a continued flow of bags from the
production line to the shipping point, it is essential that such a
bag closing machine function smoothly and efficiently with a
minimum of downtime and maintenance. When a machine fails, the
plant output is immediately affected, the product flow rapidly
slowing down and soon coming to a halt. Such stoppage is felt at
all points along the production line. It is an object of the
present invention to provide an automatic bag closing machine
requiring a minimum of supervision and repair and a maximum of
smooth, trouble-free operation.
Many bag closing machines close an open top bag by stitching the
top of the bag to prevent the contents escaping. A problem often
arises with this closure technique if the contents of the bag are
powdery since such material can escape between the stitches or even
through the holes in the bag made by the sewing head needle. To
meet this problem, bags containing such material have a length of
tape folded over the open top of the bag, the tape being supplied
from a tape reel attached to the sewing machine and the tape
unreeling continuously as bags flow through the machine and have
the tape folded over each successive bag. Even if the contents of
the bag are not powdery it is popular with many manufacturers to
stitch a tape over bags that are to contain consumer products since
a taped closure presents a more marketable appearance.
Another object of the invention is to provide an automatic
apparatus to clip the tape at predetermined distances from the
leading and trailing edges of the bag. Many manufacturers prefer an
"ear" of tape to extend from each side of the bag closure to reduce
the likelihood of the stitching unraveling and to improve the
appearance of the bag, the ear length varying to suit the
preference of individual manufacturers. Consequently the bag
closing machine must be capable of producing a range of required
ear lengths.
Taped closures over bag tops are known to the art and such bag
closing machines are well established. All such known machines,
however, have elaborate electrical, mechanical, or
electro-mechanical control systems for actuating the machine. These
control systems usually have quite elaborate electrical or
mechanical systems and numerous moving parts which wear rapidly and
require frequent repair when subjected to the heavy bag volume of
most industries. The high volume places a severe strain on these
elaborate control systems, and the numerous moving parts and
component systems associated with the prior art bag closing control
systems have substantially reduced the reliability of such control
systems, resulting in substantial downtime and maintenance expense,
and even more important, production line stoppage when bag flow
comes to a halt due to control system failure.
SUMMARY OF THE INVENTION
The invention comprises an automatic bag closing and taping machine
provided with a fluidic control system and fluidic bag detection
apparatus for actuating a sewing head and a tape clipper assembly
with a swinging knife.
The control system used with the invention is a fluidic system
having a plurality of logic networks therein and actuated by a
supply of pressurized air. Because the fluidic control system has
no moving parts and is actuated by the signals from the fluidic bag
detection apparatus which is also without moving parts, the
likelihood of control system failure is minimized, resulting in
greatly decreased downtime and repair expense and greatly increased
reliability, performance, and efficiency.
The bag detection apparatus includes fluidic sensors mounted along
the path followed by the bags and located at first and second
predetermined distances upstream of the knife of the tape clipper
assembly and a predetermined distance downstream of the knife.
When a bag is detected by the detection apparatus, a signal is
produced thereby to which the control system is responsive, the
control system then causing a clutch to engage to actuate the
sewing head to begin stitching the bag as the bag passes through
the machine, the sewing head continuing operation until a bag is no
longer detected by the bag detection apparatus. As the bag reaches
a point a predetermined distance upstream of the knife, a sensor
detects it and signals the control system to actuate the tape
clipping assembly with its knife which swings across the path of
the bag and returns to its starting position to sever the tape
extending downstream from the leading edge of the bag. This permits
the length of the tape ear at the leading edge of the bag to be
closely controlled. As the bag leaves the sewing head and is no
longer detected by the detection apparatus a signal is produced and
the control system actuates the tape clipper a second time thereby
clipping the tape a predetermined distance from the trailing edge
of the bag to determine the length of that tape ear. By proper
spacing of the sensors of the bag detection apparatus relative to
the tape clipper, the lengths of the tape ears extending from front
and trailing edge of the bag can be closely controlled to meet the
requirements of any industry.
When a signal from the detection apparatus is received by the
fluidic control system, the control system actuates one or more
interface valves which permit pressurized air to flow to clutch,
brake, or tape clipper assembly. If no bag is detected by the bag
detection apparatus, the control system opens an interface valve to
actuate the brake, causing the brake to engage and the sewing head
to stop operation. When a bag is detected, the control system
ceases to actuate the valve associated with the brake and instead
actuates a second interface valve causing the clutch to engage to
start the sewing head.
The tape clipper assembly has a pair of alternating pistons coupled
to a pivoting crank which actuates a knife, causing the knife to
swing across the path of the bags, the forward movement of a single
piston being adequate to swing the knife across the path and return
and simultaneously causing the remaining piston to be cocked such
that as it moves forwardly from the cocked position it also swings
the knife across the path and back. Both pistons are pneumatically
actuated and each piston is supplied with pressurized air from
interface valves controlled by the fluidic control system. The
control system actuates a first piston when a bag is detected a
predetermined distance upstream of the clipper in order to clip the
leading edge of the tape and actuates the second piston when the
bag detection apparatus no longer detects a bag thereby assuring
that the tape is clipped a predetermined distance from the trailing
edge of the bag as it leaves the machine and that successive bags
are separated from one other.
The invention also includes a method of closing taped bags with a
bag closing machine having a fluidic control system wherein bags
passing through the machine are detected by a fluidic bag detection
apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective of a bag closing machine embodying
the invention.
FIG. 2 is a schematic circuit diagram showing the fluidic control
system and its relationship to the bag closing machine.
FIG. 3 is a side elevational view of the sewing head of the bag
closing machine showing the external structure of the tape clipper
assembly.
FIG. 4 is a bottom view of the bag closing machine taken in the
direction of arrows 4--4 of FIG. 1 showing the location of sensors
along the path of the bags.
FIG. 5 is a sectional perspective showing the internal structure of
the tape clipper assembly.
FIG. 6 is an enlarged view of a switching subnetwork of FIG. 2.
DESCRIPTION AND OPERATION OF THE INVENTION
Referring now to FIG. 1, the automatic bag closing invention 10 is
shown positioned beside conveyor 11 by which bags are moved in a
downstream direction 32 along a path 12 through the bag closing
machine for closure. A sewing head 13 located adjacent path 12 and
disclosed in U.S. Pat. No. 3,478,709 is powered by a motor 14, the
sewing head and motor being coupled by a clutch 15 and a brake 16
being provided to stop the sewing head, both clutch and brake being
commercially available pneumatically actuated units.
A reel 17 supporting a supply of tape is attached to the machine
and tape 18 is fed through the sewing head 13, passing about
stationary tape guide 19 and folding apparatus 20 which folds the
tape over the open top of each bag passing through the closing
machine 10 to produce the result shown on bag 21 where the tape 18
has been stitched to the bag by the sewing head 13. The details of
the guide 19 and folding apparatus 20 are known to the art and will
not be further discussed. As the bag passes through the sewing head
the bag top 22, which is already folded as shown and covered with
tape as it enters the sewing head has the tape stitched to the bag,
providing positive and reliable closure. A tape clipper assembly 23
is located along the path 12 of the bags adjacent the sewing head,
the internal structure and operation of the tape clipper assembly
to be described hereafter.
A control box 24 houses the fluidic control system which actuates
the bag closing machine 10. Pressurized air is supplied to the
control box 24 from factory air supply 25 through supply hose 26
and system air filter 27, assuring a supply of relatively clean
air.
Referring now to FIG. 2, which shows a fluidic control system 28
within the dotted outline and useable with the invention. A factory
supply 25 of pressurized air is connected by hose 26 to system air
filter 27, from which the air flows through a valve 29, providing a
means by which pressurized air to the machine 10 can be easily
turned off. Valve 29 is connected by hose 30 to a system manifold
31 to which air lines 33, 34, 35, 36, 37 and 38 are connected.
Air line 34 supplies air at factory pressure to a filter 39, which
further purifies the air before passing it to the fluidic logic
circuit 40. A pressure regulator 41 establishes an optimum pressure
level for the logic circuit, to be described hereafter.
Air line 33 extends to a pressure regulator 42 and thence to hose
47, emitter manifold 43, and emitter nozzles 44, 45 and 46 which
are mounted on guide 48 along the bag path 12 and form a portion of
a bag detection apparatus which will be described further
hereafter. Each of these nozzles emits a jet of air across the path
12 followed by bags as they pass through the machine 10.
From system manifold 31 air line 35 extends to clutch interface
valve 49 from which another air line 50 extends to clutch 15, the
clutch being selected among commerically available units such that
the clutch engages to transmit energy from motor 14 to the sewing
head 13 when a command signal such as a supply of pressurized air
reaches the clutch through interface valve 49. The interface valve
49 is also selected from commerically available valves, the valve
passing pressurized air from hose 35 to hose 50 when the valve is
opened by pressurized air from hose 51 supplied by the logic
circuit 40 as will be discussed hereafter. Unless the valve 49 is
opened by pressurized air from the logic circuit the valve 49 does
not permit air flow to the clutch. All of the interface valves
described in this disclosure function in identical fashion and
serve merely as a kind of pneumatic relay by which a low pressure
air flow from the logic circuit 40 can produce a higher pressure
air flow to apparatus such as brake, clutch and tape clipper
assembly to actuate them.
The system manifold 31 is also connected by hose 36 to brake
interface valve 52 throughwhich pressurized air is supplied to hose
53 which extends to brake 16, air passing through valve 52 only
when the valve is opened by a command signal such as pressurized
air supplied along hose 54 from the logic circuit 40.
The brake 16 is selected from commerically available brakes and is
constructed to engage and prevent operation of the sewing head 13
when a supply of pressurized air is supplied to it through
interface valve 52 and hose 53. When no pressurized air flows to
the brake, it disengages and does not retard sewing head
operation.
System manifold 31 is connected by air line 38 to interface valve
55 throughwhich pressurized air is supplied to hose 56 and thence
to piston No. 1 of the tape clipper assembly 23, air flowing
through the valve 55 only when the valve is opened by pressurized
air flow along hose 57 from the logic circuit 40.
Interface valve 58 is connected to system manifold 31 through air
line 37 and is arranged to pass air therethrough to hose 59 and
thence to piston No. 2 of the tape clipper assembly 23 only when
the valve 58 is opened by air flow along hose 60 from the logic
circuit 40.
An air line 34 extends from the system manifold 31 to a final
filter 39 to purify the shop air to a level compatible with the
narrow air passages of the fluidic logic network 40. The air from
filter 39 is delivered to a pressure regulator 41 from which
pressurized air at a lowered, but optimum pressure, enters the
fluidic logic network, which will now be described in detail.
Pressurized air flows directly from the regulator to inlet channels
61, 62, 63, 64 and 65 of logic subnetworks 66, 67, 68, 69 and 70,
respectively. Subnetworks 66, 67 and 68, all substantially
identical to one another, are pressure sensitive switches of a type
well known to those skilled in the fluidic logic art. Since these
switches are substantially identical, detailed structure will be
explained only for subnetwork 66.
Referring now to FIG. 6, air from regulator 41 enters inlet channel
61 of subnetwork switch 66, most of the air flow passing straight
through and out primary outlet channel 71. A small amount of fluid,
however, follows channel 72a and flows out the subnetwork along
control channel 72 in direction 73, the hose 74 and nozzle 75
forming part of sensor 76 to detect a bag obstructing the nozzle.
The nozzle 75 emits air therefrom and is positioned along the path
12 followed by the bags (FIG. 2), being positioned in confronting
relationship with air nozzle 44, already described. These two
emitting nozzles and hose 74 form a sensor well known to the
fluidic art and consequently not described further in this
disclosure. A secondary outlet channel 77 diverging at an angle
from the inlet channel 61 (FIG. 6) provides an alternative flow
path for air leaving inlet channel 61.
If a bag passes between nozzles 44 and 75 (FIG. 2) the pressure
within nozzle 75 and hose 74 (FIG. 6) increases due to the
obstructing effect of the bag, causing generation of a back
pressure and a flow reversal in control channel 72 such that air
within control channel 72 flows toward the juncture of primary
outlet channel 71 and secondary outlet channel 77, the resulting
flow along control channel 72 diverting the principal flow of air
from primary outlet channel 71 to secondary outlet channel 77 where
it exhausts to the atmosphere. When no bag is detected by the
sensor 76 the flow along control channel 72 toward the juncture
diminishes and air is instead emitted at the nozzle 75, causing the
principal flow of air to switch back from secondary outlet channel
77 to primary outlet channel 71. Due to the described behavior of
subnetwork 66, when a bag is detected at nozzle 75 the network
switches its output flow to secondary outlet 77, the buildup of
back pressure in hose 74 and resulting flow reversal providing a
signal to which subnetwork 66 responds by switching the air flow to
channel 77.
Correspondingly, the control channel 78 for subnetwork 67 is
operatively connected through hose 79 to nozzle 80 which along with
nozzle 45 collectively form a second sensor 81 substantially
identical to the sensor 76 already described. Similarly, control
channel 82 of switching subnetwork 68 is connected to hose 83 and
nozzle 84, which along with nozzle 46 comprise a third sensor 85,
all the sensors being located at predetermined locations along the
path of the bag as will be described hereafter. These three sensors
collectively comprise a bag detection apparatus and provide input
signals to the control system thereby enabling the control system
to actuate bag closing machine components at appropriate intervals
as described hereafter. It should be understood that the shown
fluidic bag detection apparatus is but one type of usable fluidic
detection apparatus and that other compatible apparatuses and other
arrangements and numbers of sensors may be used, all such
alternatives being within the purview of the invention.
Referring now to FIG. 2 the primary outlet channel 71 of switching
subnetwork 66 is connected directly to control channel 86 of
subnetwork 87 known as an "or" circuit. Network 87 has its inlet
channel 88 connected to the primary outlet channel 89 of switching
network 68. The primary outlet channel 90 of subnetwork 87 exhausts
to the atmosphere, and the secondary outlet channel 91 is connected
to the control channel 92 of a second "or" circuit 93.
The "or" circuit 93 has its primary outlet channel 94 connected to
interface valve 49 to actuate valve 49, such that when low pressure
air is supplied from channel 94 to the interface valve 49, the
valve opens, supplying air at shop air pressure to the clutch 15
which then engages to permit motor 14 to drive the sewing head,
resulting in a bag being stitched closed and moved through the bag
closing machine 10.
The secondary outlet channel 95 of "or" circuit 93 is connected to
interface valve 52, the interface valve opening to pass air from
hose 36 to hose 53 thereby causing brake 16 to engage to prevent
operation of the sewing head when air is supplied to interface
valve 52 instead of valve 49. Since air flow will occur through
either channel 94 or 95 of circuit 93, but never both, there is no
chance of clutch and brake operating simultaneously.
Switching subnetwork 67 has its primary outlet channel 96 connected
to control channel 97 of "or" circuit 98, whose inlet channel 99 is
supplied from the primary outlet channel 89 of switching subnetwork
68. The primary outlet channel 100 of "or" network 98 is permitted
to exhaust to the atmosphere, and the secondary outlet channel 101
as connected to the control channel 102 of "or" circuit 103 whose
primary outlet channel 104 is connected to interface valve 58, the
secondary outlet channel 105 being connected to interface valve 55.
Consequently when pressurized air leaves primary outlet channel 104
it opens interface valve 58 causing high pressure air to flow from
hose 37 to hose 59 actuating piston No. 2 and causing it to swing
knife 106 across the path of the bag to cut the tape extending from
the leading edge of the bag as will be further described hereafter.
When fluid instead flows out secondary outlet channel 105 of
subnetwork 103 the air flow is delivered to interface valve 55 and
opens valve 55 to transmit high pressure air to actuate piston No.
1 resulting in the knife 106 swinging across the path of the bags
to cut the tape adjacent the trailing edge of the bag to separate
the bag from the successively stitched bag.
It should be understood that the shown fluidic control system 28
and its included logic network 40 are but illustrations of types of
fluidic circuitry useful to actuate the components of the disclosed
automatic bag closing machine and that those skilled in the art can
vary and modify the shown fluidic control system to produce
substantially equivalent results, all such variations and
modifications being within the purview of the invention claimed
herein.
Referring now to FIG. 5 wherein the internal structure of the tape
clipper assembly 23 is shown, a housing 107 contains piston
cylinders 108 and 109 in which pistons 1 and 2 respectively are
mounted for sliding movement. A chamber 110 contains a crank 111
swingably mounted on crank shaft 112, the shaft being mounted in
the housing 107. The crank 111 has connecting rods 113 and 114
pivotally mounted thereto and extending to the pistons 1 and 2
respectively, the connecting rods being arranged such that when
either piston moves forwardly in the direction of arrow 115 in
response to a burst of pressurized air entering a piston cylinder,
the crank 111 pivots about the axis of shaft 112. The crank 111 has
a pivotally mounted drive link 116 extending to a bifurcated cam on
the knife drive lever 117 which is securely attached to a knife
shaft 118, the link 116 also being pivotally mounted to the cam on
the lever 117. The knife shaft 118 is journaled in the housing 107
for limited rotational movement so as to swing in the directions of
arrow 119 to in turn swing knife 106 across the path of the bags to
cooperate with anvil 120 to sever the tape.
The knife 106 has a bifurcated mounting 106a and is securely
attached to knife shaft 118 by screws 118a; the knife has a
replaceable knife edge 121. A spring 122, under compression, rests
against washer 123 and housing 107 and urges knife shaft 118 in the
direction 124 to insure positive contact between knife edge 121 and
anvil 120. The crank 111, link 116 and drive lever 117 are arranged
such that a single forward piston stroke of piston 1 causes the
knife to swing across the path of the bags to alternate position
125 (FIG. 3) and then to return to starting position 126
simultaneously moving the other piston to a cocked position 127.
The knife behaves in exactly the same fashion when piston 2 slides
forwardly to an extended position. Pistons 1 and 2 are provided
with conventional sealing apparatus to provide acceptable seals
between pistons and cylinders.
A cylinder head 128 closes the cylinder 108 and is retained against
washer 129 and shoulder 130 by snap ring 131, sealing between head
and cylinder being handled by an O-ring 132. A bumper plate 133
absorbs piston impact as the piston moves toward the cylinder head.
An elbow 134 is threaded into the cylinder head 128 and extends to
hose 56 and interface valve 55 from which air under pressure is
supplied to piston 1.
Piston 2 is substantially identical in construction to piston 1,
and the two pistons are connected to crank 111 in the shown manner
such that one piston is always extended and the other in a cocked
position permitting each piston to actuate the knife 106 and the
pistons to operate alternately. Cylinder 109 is supplied with
bursts of pressurized air through elbow 135 which communicates with
hose 59 extending from interface valve 58.
In operation, an operator first determines the proper placement of
sensors 76, 81 and 85 (FIG. 4). Nozzles 44 and 75 of sensor 76 are
moved to a position along guides 48 and 48a, respectively where
they are near the sewing needle 136 and feed dog mechanism of the
sewing head 13 since the sensor's purpose is to detect an
approaching bag so that control system 28 can actuate the sewing
head to close the bag. The sensor 76 is located a first
predetermined distance upstream of the knife 106 and also upsteam
of the needle 136. It should also be understood that all the sensor
nozzles are placed on the machine 10 at a height below the level of
the tape on each bag and thus only encounter the moving bags and do
not detect the tape.
Because sensor 81 generates the signal to cause the knife 106 to
sever the tape extending in a downstream direction 32 (FIG. 1) from
the leading edge 137 of a bag 21 passing through the machine, the
sensor 81 is positioned at a second predetermined distance upstream
of the knife along guides 48 and 48a such that the desired ear
length of tape will be extending forwardly from the leading edge of
the bag up to the knife when the bag obstructs sensor 81, thereby
assuring that the knife 106 will sever the tape at this desired
distance from the bag. This results in the downstream ear 138
having a length substantially equal to the predetermined distance
from knife to sensor 81. It should be understood that when
distances along the bag path are referred to and measured from the
knife, the measurement is made along the path 12 from the point at
which the swinging knife crosses the path.
Sensor 85 is positioned at a first predetermined distance
downstream of the knife 106 on guides 48 and 48a such that a
desired length of tape will be extending upstream from the trailing
edge 139 of the bag 21 when the bag passes sensor 85 and is no
longer detected thereby. When the bag is not detected by sensor 85
the sewing head ceases to operate and the knife 106 swings across
the path 12 to cut the tape this desired distance at the rear of
the bag thereby creating an ear 140 having a length equal to the
distance between sensor 85 and knife 106. The exact positioning of
sensors 76, 81 and 85 can be easily adjusted by loosening screws
141 which (FIG. 4) retain the sensors in position on the
guides.
After these sensors are positioned in desired locations at the said
predetermined distances from the knife, the operator connects the
system filter 27 to a factory supply of pressurized air at an
acceptable pressure such as 90 p.s.i. and opens valve 29 permitting
the air to be purified as it passes through the filter 27 and then
flows into control box 24 through hose 30, entering system manifold
31.
From the manifold 31 pressurized air flows through pressure
regulator 42 and to the emitter manifold 43 (FIGS. 2, 3 and 4) from
which it is delivered to nozzles 44, 45 and 46 on guide 48
positioned opposite nozzles 75, 80 and 84, respectively. In
addition factory air is delivered to the interface valves 49, 52,
58 and 55 through hoses 35, 36, 37 and 38, respectively, the
factory air being prevented from flowing through any of these
valves unless the valve is opened by means of a pressure impulse
delivered from the fluidic logic network 40.
Pressurized air flows from the manifold 31 through filter 39 and
pressure regulator 41 which establishes a desired optimum pressure
level of air supplied to the fluidic logic network 40 through hose
142 which provides a common connection to inlet channels 61, 62,
63, 64 and 65 within the fluidic logic network.
When no bags are detected by the bag detection apparatus comprised
of sensors 76, 81 and 85 air flows through the fluidic logic
network and control system in the following fashion. Pressurized
air flows down inlet channel 61 of subnetwork 66, leaving the
network by primary outlet channel 71 since there is no obstructing
of nozzle 75 of sensor 76 and consequently there is no back
pressure in control channel 72 to cause air flow to divert to
secondary outlet channel 77. Consequently air flows along channel
143 to control channel 86 of "or" circuit 87. Since switching
subnetwork 68 also detects no bag, it behaves in identical fashion
to subnetwork 66 and pressurized air flows along inlet channel 63
and out primary outlet channel 89 and along channel 144 entering
inlet channels 88 and 99 of "or" networks 87 and 98. Air flowing
along inlet channel 88 of circuit 87 is diverted into secondary
outlet channel 91 by the flow from control channel 86. This fluid
leaves secondary outlet channel 91 and enters control channel 92 of
"or" circuit 93 causing the stream of pressurized air from inlet
channel 64 to be diverted into secondary outlet channel 95 which is
connected through hose 54 to interface valve 52 thus supplying a
command signal to valve 52 to cause it to open.
Pressurized air reaching interface valve 52 is adequate to open the
valve and permit factory pressure air to be transmitted directly
along hose 53 to the brake 16 causing the brake to engage and
prevent operation of the sewing head. It should be understood that
the electric motor 14 of sewing head 13 is activated at the same
time the factory air supply is turned on, the motor being run
continuously and coupled to the sewing head by clutch 15 when
stitching is desired.
While no bag is detected by the bag detection apparatus, fluidic
switching subnetwork 67 behaves in identical fashion to switching
subnetwork 66 and pressurized air flows directly in inlet channel
62 and out primary outlet channel 96 then flowing along channel 145
to control channel 97 of "or" circuit 98, causing the air stream
originating at primary outlet channel 89 of switching subnetwork 68
to be diverted into secondary outlet channel 101 of the "or"
circuit 98. Consequently the pressurized air flows to the control
channel 102 of "or" circuit 103 causing the air flow to be diverted
to secondary outlet channel 105 and thence along hose 57 to
interface valve 55, opening the valve and permitting factory air to
flow from manifold 31 through hose 38, valve 55, hose 56 and to
piston No. 1. Such air enters piston cylinder 108 (FIGS. 2 and 5)
through elbow 134. Since piston No. 1 is in an extended position,
it cannot move forwardly and consequently there is no further
movement of piston No. 1 or of the knife 106. It is thus seen that
when no bag is detected by the bag detection apparatus neither
sewing head nor tape clipper assembly operates.
As a bag moves along the path 12, the bag first encounters sensor
76 and obstructs the air being emitted from the nozzles 75 and 44,
resulting in a pressure buildup in hose 74 which produces a flow
reversal in the control channel 72 diverting the air stream from
primary outlet channel 71 to secondary outlet channel 77 from which
the air exhausts to atmosphere. This results in no air stream along
connecting channel 143 and consequently the air stream entering
input channel 88 of "or" circuit 87 is no longer diverted along
secondary outlet channel 91 and switches to primary outlet channel
90, exhausting to the atmosphere. This in turn eliminates the
supply of pressurized air reaching control channel 92 of "or"
circuit 93, causing the air stream from inlet channel 64 to divert
from secondary outlet channel 95 to primary outlet channel 94.
Since interface valve 52 then no longer has a pressure impulse from
hose 54 opening the valve, it closes, and the brake 16 is no longer
supplied with factory air along hose 53, and consequently, it
releases. Simultaneously, interface valve 49 is opened by an air
flow command signal from primary outlet channel 94 and opens,
causing the clutch 15 to be supplied with factory air through hose
50 resulting in the clutch engaging the sewing head with the
already operating motor 14 and the sewing head beginning operation
to stitch the tape 18 (FIG. 1) over the bag top and urge the bag
through the sewing head. It should, of course, be understood that
the bag has already been folded closed prior to entering the sewing
head and has had tape folded over the open top as it entered the
sewing head. The sewing head stitches the tape securely to the bag
and at this time the bag has a length of tape extending forwardly
from the leading edge of the bag.
As the bag moves through the sewing head along the path 12 it next
reaches sensor 81 and obstructs its nozzles 80 and 45 which
generates sufficient pressure in hose 79 to cause the air to
reverse its flow in control channel 78 and divert the air stream
passing along inlet channel 62 from primary outlet channel 96 to
secondary outlet channel 147, exhausting to the atmosphere. Since
no flow now passes through connecting channel 145, pressurized air
entering inlet channel 99 of "or" circuit 98 is no longer diverted
to secondary outlet channel 101 and returns to primary outlet
channel 100, exhausting to the atmosphere. Consequently the control
stream 102 of "or" circuit 103 no longer passes significant air
flow and air entering inlet channel 65 switches from secondary
outlet channel 105 to primary outlet channel 104. Since interface
valve 55 is no longer supplied with an air flow, the valve 55
closes and no more factory air reaches piston 1. Simultaneous with
the closing of interface valve 55, pressurized air is supplied to
interface valve 58, opening the valve 58 and sending pressurized
air to piston 2 through hose 59 and elbow 135. This drives piston 2
forward to an extended position, the connecting rod 114 swinging
crank 111 about crank shaft axis 112. As the crank swings, drive
link 116 swings knife drive lever 117 resulting in partial rotation
of knife shaft 118 in one direction and then the other. This
partial rotation is ample to swing the knife 106 across the path of
the bag to position 125 (FIG. 3) and back again to starting
position 126. The knife edge 121 cooperates with anvil 120 (FIG. 5)
to clip the tape 18 extending in a downstream direction 32 from the
leading edge 137 (FIG. 1) of the bag. Naturally, the knife severs
any cord or thread chain from the sewing head which may be
extending between the bag and the sewing head. As the piston 2
reaches its extended position, piston 1 is restored to a cocked
position by movement of crank 111 transmitted to the piston 1
through connecting rod 113. Continued transmission of factory air
to piston cylinder 109 retains the piston 2 in an extended
position.
As the bag continues to move through the sewing head it is detected
at sensor 85 causing the air emitted from nozzles 84 and 46 to be
partially obstructed causing a buildup of pressure in control
channel 82 and a reversal of flow in subnetwork 68. This flow
reversal diverts air flow from primary outlet channel 89 to
secondary outlet channel 149, exhausting to the atmosphere. When
this occurs no air flow is delivered to inlet channels 88 and 99 of
"or" circuits 87 and 98 respectively, resulting in no fluid flow
passing along channels 91 and 101 to control channels 92 and 102,
respectively, of "or" circuits 93 and 103, respectively.
Consequently air flows directly down inlet channel 64 of "or"
circuit 93 and out primary outlet channel 94 to interface valve 49,
thus assuring that the clutch 15 is supplied with factory air to
maintain it in engagement and actuate the sewing head even if the
bag is no longer detected at sensor 76. Consequently the sewing
head continues operation until no bag is detected at either sensor
76 or sensor 85.
So long as a bag is detected at sensor 85, there is no air flow in
control channel 102 of "or" circuit 103 resulting in the air flow
from inlet channel 65 of circuit 103 passing straight through the
circuit and leaving by primary outlet channel 104 causing interface
valve 58 to open and piston 2 to receive factory air. Since piston
2 is already extended, no further clipping action occurs as
yet.
At the instant that the bag passes sensor 85 and no longer
obstructs air flow from the nozzles 84 and 46, pressurized air
passing down inlet channel 63 of switching subnetwork 68, flows
straight out primary outlet channel 89, dividing to enter inlet
channels 88 and 99 of "or" circuits 87 and 98, respectively. Since
neither sensor 76 nor 81 now senses any bag, air flow passes
directly through subnetworks 66 and 67 leaving by primary outlet
channels 71 and 96, respectively. Air flow from subnetwork 67 flows
directly to control channel 97 of "or" circuit 98 diverting the air
flow from primary outlet channel 100 to secondary outlet channel
101. Air flows from secondary outlet channel 101 into control
channel 102 of "or" circuit 103 causing the air flow of circuit 103
to be diverted to secondary outlet channel 105 to open interface
valve 55. Factory air flows through interface valve 55, entering
piston cylinder 108 and driving piston 1 forward, resulting in the
crank 111 swinging to in turn move link 116 and rotate knife shaft
118 about its axis and return it to starting position causing knife
106 to swing across the path 12 to sever the tape 18 a
predetermined distance from the trailing edge 139 of the bag 21,
(FIG. 1) the movement of piston 1 also resulting in piston 2 being
retracted to a cocked position.
Simultaneous with the actuation of piston 1, air flows from primary
outlet channel 89 of subnetwork 68 to inlet channel 88 of "or"
circuit 87 and is diverted to secondary outlet channel 91 by flow
along control channel 86 from switching subnetwork 66. This results
in air flowing to control channel 92 of "or" circuit 93, diverting
the air flow from primary outlet channel 94 to secondary outlet
channel 95. Since flow then no longer can reach interface valve 49,
the clutch 15 disengages. Pressurized air is instead supplied to
interface valve 52 which opens to pass factory air to brake 16
which then engages and the sewing head 13 ceases operation until
the next successive bag is detected by the bag detection
apparatus.
The described bag closing machine thus detects an approaching bag
with sensor 76, releases the brake 16, and engages the clutch 15 to
start sewing head operation to attach the tape to the bag, sewing
head operation continuing until no bag is detected at sensor 85.
When the bag is detected by sensor 81, the tape extending
downstream of the leading edge of the bag is clipped. When the bag
is detected by sensor 85, the sewing head operation is continued
even if sensor 76 is not obstructed. When sensor 85 ceases to
detect a bag, the tape extending upstream from the trailing edge of
the bag is clipped and the clutch disengaged and the brake engaged
to stop sewing head operation.
It should also be understood that the tape clipper assembly, the
fluidic control system, and the bag detection apparatus disclosed
herein may form an accessory which may be attached to already
manufactured tape bag closing machines. If it is not necessary that
the sewing head be stopped and started by the accessory, one can
further simplify the fluidic control system. Such simplification is
well within the skill of the art and will not be described further
herein, but it should be understood that such an accessory, whether
or not with a simplified control system, is within the purview of
the claimed invention.
While the preferred embodiments of the present invention have been
described, it should be understood that various changes,
adaptations and modifications may be made therein without departing
from the spirit of the invention and the scope of the appended
claims.
* * * * *