US3538960A

US3538960A - Twist-tie bag closing machine

Info

Publication number: US3538960A
Application number: US706572A
Authority: US
Inventors: John D Tetrick
Original assignee: Doughboy Industries Inc
Current assignee: Doughboy Industries Inc; Doboy Packaging Machinery Inc
Priority date: 1968-02-19
Filing date: 1968-02-19
Publication date: 1970-11-10
Anticipated expiration: 1987-11-10
Also published as: GB1264993A; DE1761001A1; JPS4834160B1

Description

United States Patent [72] inventor John D. Tetrick White Bear Lake, Minnesota [2i] Appl. No. 706,572

[22] Filed Feb. 19, 1968 v [45] Patented Nov. 10, 1970 [73] Assignee Doughboy industries, Inc.

New Richmond, Wisconsin a corporation of Wisconsin [54] TWIST-TIE BAG CLOSING MACHINE 3,369,573 -2/l968 Bakeretal Primary ExaminerLowell A. Larson Attorney-Williamson, Palmatier and Bains ABSTRACT: A machine for closing the open, gathered ends of flexible bags incorporates a rotatably mounted cam plate and roller assembly which serves to carry out the several functions of feeding a length of tying strip into position, actuating a knife which cuts off the desired length of tying strip, drives a forming arm which forms the ribbon in a loop around the neck of the bag to be closed, and actuates the drive mechanism for rotating the hooked twister which twists the ends of the tying strip together. A clutch mechanism connected to the drLvc shaft for the cam plate and roller assembly is arranged to be engaged and disengaged by a movable member which is actuated by the neck of a bag when it is moved into position to be closed by the tying machine.

' Panama Nov. 10,1970 5 3,538,960

, Sheefiof? mvsw'roa Jo /v D. TETE/GK A fro/24151 5 Patnted Nov. 10,1970

Sheet I 'INVENTOR.

Jew/M2. TETE/CK 1 TWIST-TIE BAG CLOSING MACHINE Packaging machines of the type which close the open, gathered ends of flexible bags, such as the plastic bags in which produce and bakery goods are packaged, by twisting a flexible tie strip around the neck of the bag are known and in widespread use. Most of these machines are designed and constructed to accommodate a production line type of operation wherein bags to be packaged are fed by the machine on a conveyor, and the gathering and tying of the bag neck are carried out automatically. Production line machines of this type are necessarily quite sophisticated and expensive.

l have developed a small, twist-tying machine, which is particularly designed for but not limited to manual operation, and which is particularly characterized by its simplicity of construction and operation.

These desirable objectives are obtained by virtue of an operating mechanism which incorporates as its basic operating component a cam assembly which initiates all of the necessary mechanical steps in the tying operation as it moves through the predetermined path. Not only does the aforesaid cam assembly actuate the tying strip feed and cutoff devices, but it also operates a linkage mechanism for moving a forming arm which bends the tying strip back on itself around the neck of a bag.

As a further advantageous feature of my improved tying machine, the cam assembly is arranged to actuate a rotating mechanism for a twister hook which twists the ends of the tying strip together, the cam assembly being moved to initiate this twisting operation after the tie strip forming step has been completed.

A particularly unique and important feature of my invention resides in the utilization of a movable member responsive to the movement of a bag into a tying position at the head of the machine to engage and disengage a clutch which transmits rotary power to a drive shaft for the aforesaid cam assembly.

These and other objects and advantages of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings. wherein like reference numerals are used to refer to like elements throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of the tying machine of this invention with the various parts shown in the position they will assume prior to the initiation of a tying operation;

FIG. 2 is a perspective view of the double-hook tying device; I

FIG. 3 is a perspective view showing the cooperative relationship of the tying strip cutoff knife and cutting block;

FIG. 4 is a top view similar to FIG. 1 showing the operative parts at an intermediate stage of the tying operation;

FIG. 5 is a top view of the tying machine showing the parts in the position they will assume as the tying operation is being completed;

FIG. 6 is an enlarged, fragmentary view showing the twister in engagement with the ends of the tying strip;

FIG. 7 is a bottom view of the tying machine showing the clutch and drive mechanism;

FIG. 8 is am exploded perspective view of the clutch mechanism; and

FIG. 9 is a perspective view of a bag having a gathered neck tied by the machine of this invention.

The bag tying apparatus of this invention is shown in FIG. 1 as mounted on a plate ll having a head 2 which is slotted at 4 to accommodate the gathered neck of a bag. Head 2 is normally covered by a housing and infeed guide member 6. A spool 8 carrying a roll of tying ribbon 10 is rotatably mounted within recess 12 of plate 1 on shaft 14. Ribbon 10 may be any strip of material which is flexible, and capable of holding a twisted shape. Paper or plastic coated wire has been found to be particularly suitable for this purpose. Ribbon 10 is taken off the top of spool 8 and directed over the top of brake arm l6 through guide sleeve 18 to a feed mechanism. Brake arm 16 is pivotally mounted at its lower end to support bar 20, and normally rests on the top of spool 8 to prevent the uncoiling of tying ribbon 10. When ribbon 10 is pulled by the advancing mechanism described below, it will lift arm 16 allowing spool 8 to rotate and release the desired amount of ribbon.

In order to prepare the tying machine for operation, tape All is fed by hand between rotatably mounted, rubber idler wheel 22 and cam surface 24 of cam plate 26. The end of tape it) is then directed through guide sleeve 28, and aperture 36 in entoff block 32. Slotted guide member 34 adjacent cutting block 32 serves to guide ribbon 10 forwardly to the outer extremity of pivotally mounted forming finger 3, which has a ribbonforming recess 38 therein. Forming finger 36 is pivoted about point 39 by interconnected links 14) and 41 assembled at the forward end of arm 42. Arm 42 pivots about point 4-3, and carries ribbon cutoff knife 44- on the inside face of its forward end. As is best shown in FIG. 3, knife 4% is positioned adjacent forward face 31 of cutting block 32, and cooperates therewith to sever ribbon 10 as arm 42 is pivoted in the direction indicated by the arrow.

Pivotal movement is imparted to arm 42 by roller cam 46 which is rotatably mounted on cam plate 26 to form a unitary cam assembly therewith. Cam plate 26 extends between arm 42 and plate 1 in order to permit cam surface 2 thereof to drivingly engage ribbon llll against idler 22 as well as to allow carn roller 46 to engage indented follower surface .-8 on arm 42. Cam plate 26 is rotated by a drive mechanism hereinafter described in order that cam surface 24 and roller 46 may initiate the ribbon feeding, cutoff, forming and tying operations as described below.

For the purpose of twisting the ends of a length of ribbon it together so as to tightly close the neck of a bag, I provide hook 50 mounted on the end of rotatably supported shaft 52. With reference to FIG. 2, hook 50 is provided with oppositely turned hook end portions Sll and 53 which engage the op posite ends of a length of tying ribbon as shaft 52 is rotated. Shaft 52 is rotated by means of a pull cord 54 which is coiled around shaft 52 and fastened thereto at one end 55. Referring again to FIG. 1, a coil spring 56 is also secured to shaft 52 and serves to return it to its rest position after pull cord 54 has been released.

One end of pull cord 54 is attached to linkage arm 58, which has gear 60 connected to one end thereof and is rotatable therewith about pivot point 62. The teeth on gear 66 mesh with the teeth on drive gear 64 which is rotated by linkage arm 66 to which it is connected. The rotational movement of arm 66 about pivot point 6% so as to accomplish the actuation of pull cord 54 is achieved by rotating roller cam 46 against the upper end of arm 66. Attached to the upper end of linkage arm 66 at floating pivot point'70 is link 72 which is connected to arm All by means of slot '74 therein.

For the purpose of rotating the assembly of cam plate 26 and roller 46 so as to carry out the various steps in a bag tying operation, I provide a drive mechanism which will now be described with reference to FIGS. 7 and 8. Connected to the underside of cam plate 26 and extending downwardly therefrom through an aperture 76 in plate 1 is a drive shaft 76. Rotatably supported on the lower end of drive shaft 76 below plate 1, as viewed from its bottom side in FIG. 7, is a sprocket assembly 80'. Sprocket assembly 80 is held in place on shaft '76 by a collar 82, and is comprised of a sprocket wheel SM and a star wheel 86. A drive chain $8 extends around sprocket wheel 84 and is connected at its opposite end to a similar drive sprocket connected to the output shaft of a motor (not shown). Rotary power is intermittently transmitted to earn drive shaft 76 from sprocket assembly 80 by a clutch mechanism consisting of clutch arm and clutch dog 92. Clutch arm 90 is drivingly connected to cam shaft 76 by a pin 94 extending through collar 96 and an aligned hole drilled through the lower end of shaft 76. A bushing 98, and one-way clutch 100 are also mounted on the lower end of drive shaft '76 between the bottom of plate I and collar 96 of clutch arm 9% One-way clutch 100 insures that cam plate 26 will rotate in only the desired direction. Clutch dog 92 is pivotally secured to arm 90 by means of pin 102, which extends through bushing 104 in arm 90 and has grip ring 106 attached to its upper end. Release pin lllfl for clutch dog 92 extends upwardly therefrom. Clutch dog 92 is biased towards a position in driving engagement with star wheel 86 by spring 110. A clutch actuating assembly consisting of pivotal arm 112 having

fingers

113 and 114 at its opposite ends serves to hold clutch dog 92 in a normal position out of engagement with star wheel 36. Arm 112 is pivotally connected to plate 1 by means of cap screw 116, sleeve 118, and bushing 120. Spring 122 urges arm 112 towards the normal position indicated in phantom lines in FlG. 7 wherein finger 114 engages pin 108 and holds dog 92 out of contact with star wheel 86. Slide bar 12 extending in alignment with slot 4 is connected at its inner end to arm 112. Outer end 125 of slide bar 124 overlaps the inner end of slot 4 in position to be contacted by the neck ofa bag inserted within slot 4.

in order to ready the tying machine for operation, the motor to which drive sprocket 88 is connected is started, thereby causing sprocket assembly 80 to rotate. in order to engage the clutch mechanism and start cam shaft 76 rotating, the gathered neck portion R28 of a bag 126 is inserted into slot 4 and forced against end 125 of slide bar 124, thereby forcing bar 124- to the left in the direction indicated by the solid arrow in FlG. 7. The inward movement of slide bar 124 will pivot clutch actuating arm 112 from the phantom line position to the solid ine position shown in FlG. 7. Finger 114 will thus be moved out of engagement with pin 108 on dog 92, thereby permitting spring 120 to pull dog 92 into one of the pockets in star wheel 86. As star wheel 86 continues to rotate it will engage dog 92. and force clutch arm 90 to rotate in the direction indicated by the arcixtte arrow. Cam drive shaft 76, being connected to collar 96 of clutch arm 90, will rotate therewith, thus starting cam plate 26 and roller 46 to rotate through a predetermined operational path. Assuming that cam plate 26 is in the position shown in FlG. 1 with a length of tying strip already having been advanced into position, the rotation of cam plate 26 by shaft 76 will bring roller 46 into engagement with follower surface 48 of arm 42. As roller 46 bears against arm 5-2 in the manner shown in FIG. 4, arm 42 will pivot in a counterclockwise direction so as to move cutting knife 44- across cutoff block 32 to sever a length 11 of the tying ribbon. This same movement of pivotal arm 42 will cause

links

40 and 41 connected thereto to simultaneously swing forming fingers 36 about pivot point 39 to the position shown in FIG. 4. As finger 36 rotates around pivot point 39 recess 33 therein will bend ribbon strand it around bag neck 128 to the position shown in FIG. 4. As cam plate 26 continues to rotate, roller cam 46 will be brought to bear against the upper end of linkage arm 66 thereby moving arm 66 in a clockwise direction as indicated by the arrows in FlG. 5. As arm 66 pivots about point 68, gear attached thereto will rotate in the same direction, thereby driving gear 60 in a counterclockwise direction. Linkage arm 58 connected to gear 60 will thus rotate in the same direction about pivot point 62, thereby exerting a pulling force on cord 54. As cord 54 is pulled by linkage arm 58 shaft 52 will rotate, and hook 50 at the outer end thereof will twist-tie ribbon strand ll about neck 12% of bag 126.

The ribbon twisting action of rotary hook 56 is best illustrated in FlG. 6. Oppositely turned, hooked end portions Si and 53 of hook 50 will engage opposite ends 13 and 15 of riblion strand ll and twist them together from the end ofshaft 52 towards bag neck 126. As a result of the uniform twisting action of double hooks 51 and 53, ends 13 and 15 of ribbon strand it will be tied together in a tight, even twist.

As cam roller 46 moves from the position shown in FIG. 4 to that shown in FIG. 5, linkage arm 66 will first push floating link 72 through a lost motion path in which slot 74 therein :nidcs upwardly over fastener 75 secured to arm 42. During this time arm 42 will thus be maintained in the position shown in FlGS. and 5 wherein forming finger 36 holds wrapper strand 11 around bag neck 126 while linkage arm 66 rotates a sufficient distance to carry out the aforesaid twisting opera tion by hook 5t Slot 74 is of such a length that it will move back and forth over fastener 75 on arm 4-2 as linkage arm 6f.- movcs to effect the ribbon twisting operation. As roller "16 continues to rotate against arm 66, the further clockwise movement thereof will bring the outer end of slot 74 to bear against fastener 75, and arm 42. will he pulled back to the starting position shown in FIG. 1. As cam drive shaft 76 continues to rotate roller 46 through the arcuate path indicated at 45 in FIG. 5, roller 46 will eventually be moved out of engagement with linkage arm 66. When this happens, coil spring wrapped around hook shaft 52 will exert a counterrotational force on shaft 52, whereby cord 54 will pull linkage arm 58 back to its original position. The return pivotal movement of arm 58 will cause linkage arm to also rotate back to its original position by the mechanism of meshing gears 60 and 64. At this time, cam roller 46 will have gone through approximately two thirds ofa revolution. lf bag neck 128 is left in slot 4 in engagement with slide bar 124, clutch actuating bar 2.1.2 will be maintained in the solid line position shown in FlG. 7, and finger 1. 13 thereof will interact with rotating clutch dog If. to prevent the further rotation of cam drive shaft 76. After clutch dog 92 has rotated through two thirds of a revolution from the solid line position shown in FIG. 7. release pin 1C3 attached thereto will strike finger 113 thereby forcing dog 92 out of engagement with star wheel When bag neck i233 is removed from slot 4, spring 122 will act to pivot clutch actuating arm 112 to the phantom line position shown in FlG. 7. /'.s a result, finger US will release pin ROS and clutch dog 92 and Clutch arm will continue to rotate until finge 1E4 disengages dog 92 from star wheel 86. Drive shaft 76 will now have completed one complete revolution. During the last one third of this revolution, the rotation of cam plate 26 will move earn surface 24 thereof through an arc in cooperative engagement with idler 22, whereby another length of tying ribbon will be advanced therebetween to the tying position shown in FIG. 1. The machine is now ready to begin another cycle of operation. It is to be noted that spring biased bar l9 wedges ribbon 10* against guide block 18 so as to prevent ribbon .41 from moving in a reverse direction after the required length for a tying operation has been cut off.

lf bag neck 128 is removed from slot 4 after drive shaft 76 has completed two thirds of a revolution, spring 1.22 will pivot clutch actuating bar 112 back to the phantom line position shown in FlG. 7. Finger 113 will thus be removed from the path of dog release pin 103, and cam shaft 76 will continue to rotate so as to advance an additional length of rib on into tying position. After drive shaft 76 has completed one revolution, finger 114 will strike release pin 108 and disengage clutch dog 92 from star wheel 86.

FIG. 9 shows bag 126 with its gathered neck 123 closed by

twisted ends

13 and 15 of ribbon strand 1!.

Although my improved bag tying machine is primarily designed for manual operation wherein a bag neck is gathered by hand and then moved in and out of slot manually. it would be possible to adapt my machine to a higher volume production operation wherein the bags move along on a conveyor and are automatically moved in and out of slot 4. The tying machine will normally be mounted with plate l disposed horizontally. Base 3 shown in FlG. may be utilized to support plate I in the desired horizontal position.

Those skilled in the art will readily appreciate tha the unique drive arrangement described above wherein a single cam assembly comprised of cum plate 26 and roller -35 cooperates with various linkages to as to carry out all of the necessary steps in the tying operation greatly minimizes the number and complexity of moving parts. The construction and operation of the machine is thus greatly simplified, thereby significantly reducing construction and maintenance costs. The novel bag-actuated clutch mechanism permits the drive motor to be run continuously with the tying operation being started and stopped as a bag neck is moved in and out ofslot 4.

tightly l contemplate that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the spirit and scope of my invention as defined by the following claims.

I claim:

1. ln a bag tying machine having mechanisms for feeding a strip of ribbon into position to tie a bag, cutting off the ribbon strip, forming the strip around the neck of the bag and twisting the ends of the ribbon strip together, improved actuating means for said mechanisms comprising:

a rotatably mounted cam member having cam elements thereon operative to engage and actuate said mechanisms as said elements move through a predetermined path, said cam elements comprising an extended surface on said cam member and a second cam element secured thereto for rotation therewith, said ribbon cutting, forming and twisting mechanisms having actuating elements disposed in the path of said second cam element for operation thereby in' a predetermined sequence as said second cam element rotates through said predetermined path, and further including; and

an idler wheel with which said extended surface on said cam member cooperates to feed a strip of ribbon therebetween as said cam member rotates.

2. A bag tying machine as defined in claim 1 wherein said mechanism for cutting off said ribbon strip comprises a knife mounted on an actuating element in the form of a pivotal arm which reciprocates said knife back and forth across the path of said ribbon in response to the movement of said second cam element thereagainst.

3. A bag tying machine comprising:

means for advancing a strip of tying ribbon from a ribbon roll into position to be secured around the neck of a bag;

a pivotally movable knife for cutting off said strip of ribbon;

a pivotally mounted forming finger for looping said ribbon strip around said bag neck;

common actuating means for said knife and forming finger operatively associated therewith for moving said knife and finger so as to cutoff and loop said ribbon strip; and

actuating means comprises a pivotal arm to which said knife I and forming finger are connected, whereby the movement of said arm as it is engaged by said cam element simultaneously actuates said knife and said forming finger.

S. A bag tying machine as defined in claim 4 and further including:

a twisting hook for twisting the ends of said strip of tying ribbon together, said hook being mounted on a rotatably supported shaft; and

drive means for rotating said shaft, said drive means including an actuating element therefor disposed in said path of said movable cam element, whereby said drive means is operated by the movement of said cam element against said actuating element.

6. A bag tying machine as defined in claim 5 wherein:

said drive means for said twisting hook comprises a pull cord wrapped around said shaft and having one end secured to pull means;

said actuating element for said drive means comprises a pivotal linkage arm operatively associated with said pull means, the pivotal movement of which by said cam element operates said pull means to rotate said hook shaft; and further including a return spring connected to said hook shaft and operative to return said shaft, pull means and linkage arm to their rest positions after said cam element rotates out of engagement with said linkage arm.

7. A bag tying machine as defined in claim 5, and further including a connecting link extending between said actuatin element for said drive means and said pivotal arm, said hn being operative to return said arm, and said knife and forming finger therewith, to their rest positions by the pivotal movement of said actuating element at the termination of the ribbon twisting operation.