US3672596A

US3672596A - Feeding device for strapping machine

Info

Publication number: US3672596A
Application number: US839010A
Authority: US
Inventors: Anton R Hoffmann
Original assignee: A J Gerrard and Co
Current assignee: A J Gerrard and Co
Priority date: 1969-07-03
Filing date: 1969-07-03
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A feed device for supplying a continuous length of strapping band from a supply reel having an accumulator assembly and an intermittent drive assembly. The accumulator assembly stores a variable segment of the strapping band to provide a constant supply of the strapping band to a strapping machine. The intermittent drive assembly starts to feed strapping band into the accumulator upon the stored segment reaching a certain low value at a rate greater than the withdrawal rate from accumulator and continues this feeding process until the stored segment reaches a certain high value.

Description

[ 1 June 27, 1972 Unite States Patent Hoftmann 2,934,338 4/1960 3,116,032 12/1963 Roberts 3,175,776 3/1965 Butterfield....

Primary Examiner--George F. Mauti A. J. Gerrard & Company, Des Plaines, Ill. Assistant Examiner-Milton Gerstein [73] Assignee:

[22] File? y 3 1969 Attorney-Johnson, Dienner, Emrich, Verbech & Wagner ABSTRACT [21] App]. No.2

A feed device for supplying a continuous length of strapping 242/47-O1 band from a supply reel having an accumulator assembly and "mm- B6511 25/32 an intermittent drive assembly. The accumulator assembly 142/7544, 75-43, stores a variable segment of the strapping band to provide a 242/ 156, 47.01, 55- constant supply of the strapping band to a strapping machine.

a l m d Ld mm .d 5 l [52] US. CL...

The intermittent drive assembly starts to feed strapping band References Cited into the accumulator upon the stored segment reaching a cer- UNITED STATES PATENTS tain low value at a rate greater than the withdrawal rate from accumulator and continues this feeding process until the 1 H1953 stored segment reaches a certain high value, 1 l/ l 926 1 1/ 1949 7 Claims, 6 Drawing Figures Ewing 242/47 01 x Jefi'eries..... ..242/47.0l x Lederer 242/47 01 PATENTEUJUMN m2 sum 1 OF 3 j w w H I 1.2!!!! a I FEEDING DEVICE FOR STRAPPING MACHINE BACKGROUND OF THE INVENTION This invention relates to a feeding device for providing a constant supply of strapping band to a strapping machine. One of the problems encountered in designing such a feeding device is that all strapping machines use the strapping band at an uneven withdrawal rate. To overcome this problem, the prior art feed devices have used an accumulator assembly which stores a sufficient length of strapping band to meet the immediate needs of the strapping machine. These prior art accumulator assemblies are generally quite complicated in design and do not generally have sufficient storage capacity to supply the strapping machine when wrapping large containers.

Another problem encountered in designing strapping band feeding devices is to provide an adequate driving assembly for feeding the strapping band from a supply reel to the accumulator assembly. This problem has become acute in designing a drive assembly for large size supply reels since the inertia of the large supply reel is difficult to control. The reason for this problem is that since the strapping machine withdraws strapping band from the accumulator at an uneven rate, it is necessary that the supply reel be driven for a short period of time and then stopped, i.e., an intermittent drive.

Accordingly, one of the objects of this invention is to provide a feed device for a strapping machine, which includes an accumulator assembly having a large storage capacity and which is simple but unique in construction.

Another object of this invention is to provide a feed device for a strapping machine having an intermittent drive assembly which drives astrapping band supply reel and feeds the band to an accumulator assembly at a greater rate than the rate at which the strapping band is being withdrawn from the accumulator assembly, whereby the drive mechanism for the intermittent drive assembly is energized when the strapping machine starts to operate and whereby the intermittent drive assembly starts to feed the strapping band to the accumulator assembly when the stored segment of strapping band reaches a certain low value and continues to supply the strapping band until the value reaches a certain high value.

Another object of this invention is to provide a feeding device for a strapping machine which automatically brakes the supply reel from further rotation upon each termination of withdrawing the strapping band from the feeding device.

A still further object of this invention is to provide a feeding device for a strapping machine, having an accumulator assembly for storing a sufficient segment of the strapping band that is used during one tying operation of the strapping machine, wherein the accumulator assembly has a unique but simple construction which is inexpensive to manufacture and requires little maintenance.

Another object of this invention is to provide a feeding device for a strapping machine, having an accumulator assembly for storing a sufficient segment of the strapping band to complete one tying operation of the strapping machine and having an intermittent drive assembly to supply the strapping band to the accumulator assembly from a supply reel at a greater rate than the withdrawal rate from the accumulator as sembly, whereby the intermittent drive assembly has a means for keeping the length of strapping band extending between the supply reel and intermittent drive assembly in a taut condition.

Another object of this invention is to provide a feeding device for a strapping machine having a supply reel for carrying the strapping band, an accumulator assembly for storing a sufficient segment of the strapping band to complete one tying operation of the strapping machine and an intermittent drive assembly for driving the supply reel and feeding it to the accumulator assembly to replenish the withdrawn strapping band from the accumulator assembly, whereby the entire feeding device is supported by a frame member and the parts are arranged thereon in such a manner as to require very little floor space.

Further objects and advantages of the present invention will become apparent as the following specification proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed and forming a part of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a side elevational view of a new and improved feeding device for a strapping machine constructed in accordance with the features of the present invention;

FIG. 2 is an end view of the feeding device illustrated in FIG. 1, showing the discharge end of the feeding device;

FIG. 3 is a cross sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along the line 4-4 of FIG.

FIG. 5 is a sectional view taken along the line 5-5 of FIG. I; and

FIG. 6 is a partial front elevational view of FIG. 1 taken along the line 6-6 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT There is illustrated in FIG. 1, a feeding device, generally designated by the reference numeral 10, embodying the principles of my invention and consisting of three major components: a supply reel assembly, generally designated by the reference numeral 12; an intermittent drive assembly, generally designated by the reference numeral 14; and an accumulator assembly, generally designated by the reference numeral 16. All of the components of feeding device 10 are supported by a frame, generally designated by the reference numeral 18, having a base member 20 and a vertical frame member 22. The supply reel assembly 12, is rotatably mounted on the lower portion of the vertical frame member 22 and disposed above it is the intermittent drive assembly 14, which has a housing 23 that is secured to the vertical frame member 22 by cross bars 24 and 25 (FIG. 2). To support the accumulator assembly 16, an integral arm member 26 extends upwardly and forwardly from the upper end of housing 23.

To provide a constant supply of strapping band to the strapping machine, the accumulator assembly 16 stores therein a sufficient quantity of strapping. band B to make one tie around a container being wrapped. Each time the stored segment in the accumulator assembly 16 reaches a certain low value, the intermittent drive assembly 14 is actuated to drive the supply reel assembly 12 and replenishes the supply of strapping band in the accumulator assembly 16 until the stored segment reaches its maximum storage capacity.

The accumulator assembly 16 has a simple but unique construction of upper and lower C-shaped

tubular members

27 and 28 through which a segment of the strapping band is threaded and stored therebetween. The upper tubular member 27 is secured to the forward upper end of vertical frame member 26. To permit the strapping band B to enter and exit form the accumulator assembly 16, the upper tubular member 27 is formed as two quarter

arcuate section

30 and 32, which are open at both ends and offset from each other (FIGS. 1 and 2). The lower C-shaped tubular member 28 has a semicircular configuration with open ends which are flared outwardlyand is supported in space by the stored segment of the strapping band B. To guide the lower tubular member 28 in a substantially vertical path as the stored segment increases and decreases in length, guide rods 34 and 35 (FIG. 2) may be provided which are secured between the extension 33 (FIG. I) of base member 20 and the upper end of vertical frame member 26 to serve as a track or guideway for a carriage 80, as shown in FIGS 2 and 3. Carriage SO-consists of a tubular member 82 having two ball bushings supported in its inner bore and two cross bars 84 and 86 extending perpendicular from its upper and lower ends. Cross bar 84, having a rectangular-shaped cross section, fits through a rectangular opening in cross bar 88 of lower tubular member 28 and has an opening 90 in its outer end through which guide rod 35 is threaded. Similarly, lower cross bar 86 fits through a rectangular opening in the middle section of tubular member 28 and has an opening in its outer end adapted to be disposed around guide rod 35.

It will be appreciated that the accumulator assembly 16 can be designed to store any desired length of strapping band and that its storage capacity is determined by the distance the upper tubular member 24 is disposed above the base member 20. It is generally desirable to design the accumulator assembly 16 to have sufficient capacity to supply one tie for a container being wrapped in the strapping machine.

To replenish the supply of stored strapping band Bin accumulator assembly 16 as it is withdrawn by the strapping machine, an intermittent drive assembly 14 is provided which drives the supply reel assembly 12 and feeds a length of strapping band B into the accumulator assembly 16. The intermittent drive assembly includes a cylindrical drum 36 mounted on the end of a drive shaft 38 (FIG. 2) which extends horizontally from the upper portion of vertical frame member 22. To guide the strapping bands around the periphery of the cylindrical drum 36 in a spaced spirally-wound fashion, a guide member 40 (See FIGS. and 6) is provided, which consists of a plurality of U-shaped rod elements 42 disposed in close spatial relationship to the lower portion of the cylindrical drums peripheral surface across the width of the drum 36. Each U-shaped element 42 has a relatively rigid structure extending at a slight transverse angle relative to drum 36 and its

opposite ends

43 and 45 are secured to

cross bars

49 and 51 of the housing 23, as depicted in FIG. 5. As can be seen from FIGS. 1, 5 and 6, strapping band B coming from the supply reel assembly 12 starts to wrap around the peripheral surface of the cylindrical drum 36 at the right edge thereof and after several convolutions, is fed from the left edge of the drum 36 through channel guide member 47 to the accumulator assembly 16. To keep the length of strapping band B taut between the supply reel assembly 12 and the intermittent drive assembly 14, a pressure roller 44 (FIGS. 1 and 5) is pivotally mounted to the side wall 46 of housing 23 such that the roller 44 rests on the peripheral surface of cylindrical drum 36. Thus, as the strapping band enters the intermittent drive assembly 14, it rolls between the peripheral drum surface and the roller 44 to maintain the strapping between this point and the supply reel assembly 12 in a taut condition.

The means for driving the drive shaft 38 and associated cylindrical drum 36 is provided by an electric motor 50 which is interconnected to the drive shaft 38 through a conventional chain and sprocket assembly, generally designated by the reference numeral 52, which is housed in the vertical frame member 22 as illustrated in FIG. 2. The circuit to the electric motor 50 is closed by a conventional fluid-actuated valve switch assembly 54 which is actuated by a signal received through hose 55 that is connected to the strapping machine. When a signal is received by the fluid actuated switch assembly 54, it closes the electrical circuit to energize electric motor 50 which starts to drive the drive shaft 38 and associated cylindrical drum 36. The motor 50 continues to drive the drive shaft 38 at a constant speed until the signal from the strapping machine terminates.

The supply reel assembly 12 consists of a spool or reel structure 56 having circular plate members 60 and 62' fixedly mounted on a mandrel 64. The spool 58 is rotatably mounted in a bearing assembly 66, supported in an opening formed through the sides of vertical frame member 22. Because the supply reel 12 has a large mass, its inertia will continue to rotate spool 56 after the pulling force from drive assembly 14 terminates, which makes it necessary to provide some sort of braking means for spool 56. To keep the spool 56 from rotating after the driving force from intermittent drive assembly 14 terminates, an air brake 68 is provided, which is energized when lower tubular member 28 drops to its lowermost position, it contacts a sensing device 72 (See FIGS. 2 and 4), which actuates air brake 68. The sensing device is depicted in FIGS. 2 and 4 as an air valve 74, but any other conventional sensor could be used, such as a microswitch. The air valve 74 is preferred, however, in this embodiment since it can be connected directly into the air system leading to air brake 68 (not shown).

For purposes of better understanding the operation of my invention, a brief description of the operation of feed device 10 will now be given. Before the strapping machine starts withdrawing strapping band B from the accumulator assembly 16, the parts of the accumulator assembly 16 would be in the position shown in FIG. 1, with the maximum amount of stored band B being stored therein. Also the convolutions of strand B wrapped around the cylindrical drum 36 would be in an expanded, nonfrictional engagement position. When the strapping machine is energized a signal will be received via air tube 55 from the strapping machine actuating the fluid actuated switch assembly 54 to close the electrical power circuit connected to the electric motor 50, which starts to drive the drum 36 at a constant speed. Since the convolutions of strapping barld wrapped around the drum 36 are in nonfrictional engagement, the rotation of the drum 36 does not provide a pulling force on the supply reel 56. When the strapping machine starts withdrawing band B from the accumulator assembly 16, the lower tubular member 26 is pulled upwardly along the vertical axis of the accumulator assembly 16 and the loop of wire in the accumulator assembly 16 exerts a stronger pulling force on the strip of band extending from the drum 36, which causes the convolutions wrapped around drum 36 to contract and frictionally engage the periphery of the drum 36. When all the convolutions of strapping band frictionally en gage the peripheral surface, a pulling force is exerted on the strip of band extending between the drum 36 and the reel 56 which causes the reel to be driven and band B is fed through the intermittent drive assembly to the accumulator assembly 16. This driving of the supply reel assembly 12 and feeding the strapping band B to the accumulator assembly 16 continues until the maximum segment of band is again stored in the accumulator assembly 16, as shown in FIG. 1, and thereafter the length of band, between the upper tubular member 32 and the cylindrical drum 36 which can no longer freely feed forward, creates a back force on the convolutions around the drum, which back force pemrits the convolutions to expand away from the surface and immediately stop the pulling force exerted on supply reel assembly 12. It is noted that in order for the feeding apparatus 10 to operate in the manner just described, it is necessary that the intermittent drive assembly feed the strapping band into the accumulator assembly 16 at a greater rate than it is withdrawn from the accumulator as sembly by the strapping machine. The intermittent drive assembly 14 will, of course, be energized each time the stored segment in the accumulator assembly 16 reaches the minimum quantity that permits the convolutions around the periphery of drum 36 to frictionally engage the peripheral surface thereof.

When the stored segment in the accumulator 16 reaches its maximum stored quantity, lower tubular member 28 has dropped to its rest position on top of air valve 74 to close its top opening, which sends a signal through an air system to actuate air brake 68 and thereby halt the inertial rotation of spool 56.

I claim:

1. A feed device for supplying a continuous length of strapping band to a strapping machine comprising a rotatably mounted supply reel adapted to carry a continuous length of strapping band, accumulator means for storing a variable segment of the strapping band to provide a constant supply of strapping band to a strapping machine and a means for intermittently driving said supply reel and feeding the strapping band to said accumulator means at a greater rate than the withdrawal rate of strapping band from said accumulator means, wherein said intermittent drive means automatically commences driving said supply reel when said segment reaches a certain minimum length and terminates driving said supply reel when said segment reaches a certain maximum length and comprises a drum mounted on a drive shaft, means for driving said drive shaft, and means for guiding the strapping band around the periphery of said drum to form at least two spaced spirally-wound convolutions, wherein when said stored segment reaches said minimum length the pulling force on said convolutions is increased a sufficient amount to cause said convolutions to contract into frictional engagement with said periphery of said drum providing a steady pulling force on said supply reel until said stored segment reaches said maximum length which causes a back force in the length of band between said drum and accumulator, resulting in a nonfrictional loose engagement of said convolutions with said drums periphery and preventing further feeding to said accumulator.

2. A feed device as defined in claim 1 wherein said accumulator means consist of upper and lower strap guide means through which said segment of the strapping band is threaded to form a variable length loop configuration, means for mounting said upper strap guide means above said lower strap guide means, and track means for guiding said lower strap guide means in a straight path towards and away from said upper strap guide means, wherein said lower strap guide means moves upwardly towards said upper strap guide means as said segment of the strapping band decreases towards said minimum length.

3. A device as defined in claim 2, further comprising means to brake said supply reel against further rotation in response to said lower strap guide means moving downwardly to a position where said maximum segment is stored in said accumulator.

4. A feed device as defined in claim 1, wherein said said drive shaft is driven by the output shaft of a motor, and means for energizing said motor in response to a signal received from the strapping machine.

5. A feed device as defined in claim 3, wherein said brake means includes an air valve disposed adjacent to the position of said lower strap guide means when said segment reaches said maximum length and an air brake mounted on the shaft of said supply reel, whereby said air brake is actuated when said air valve is closed by said lower strap guide means.

6. A feed device for supplying a continuous length of strapping band to a strapping machine, comprising a frame member, a first drive shaft rotatably mounted on said frame member and carrying a supply reel adapted to hold a continu ous length strapping band, a second drive shaft rotatably mounted on said frame member adjacent to said first drive shaft and carrying a cylindrical drum, means mounted on said frame member for guiding the strapping band around the periphery of said drum to form at least two spaced spirallywound convolutions, means for driving said drum, and accumulator means supported by said frame member to store a variable segment of the strapping band for providing a constant supply of the strapping band to a strapping machine, wherein said drive means intermittently feeds the strapping band to said accumulator means at a greater rate than the withdrawal rate of strapping band from said accumulator.

7. A feed device as defined in claim 6, wherein said accumulator means consist of upper and lower strap guide means through which said segments of the strapping band is threaded to form a variable length loop configuration, means for supporting said upper strap guide means above said lower strap guide means on said frame member, a pair of spaced vertical rods supported between said upper strap guide means and the base of said frame member for guiding said lower strap guide means towards and away from said upper strap guide means, whereby said lower tubular member moves upwardly as said segment of strapping band is decreased in length.

Claims

1. A feed device for supplying a continuous length of strapping band to a strapping machine comprising a rotatably mounted supply reel adapted to carry a continuous length of strapping band, accumulator means for storing a variable segment of the strapping band to provide a constant supply of strapping band to a strapping machine and a means for intermittently driving said supply reel and feeding the strapping band to said accumulator means at a greater rate than the withdrawal rate of strapping band from said accumulator means, wherein said intermittent drive means automatically commences driving said supply reel when said segment reaches a certain minimum length and terminates driving said supply reel when said segment reaches a certain maximum length and comprises a drum mounted on a drive shaft, means for driving said drive shaft, and means for guiding the strapping band around the periphery of said drum to form at least two spaced spirally-wound convolutions, wherein when said stored segment reaches said minimum length the pulling force on said convolutions is increased a sufficient amount to cause said convolutions to contract into frictional engagement with said periphery of said drum providing a steady pulling force on said supply reel until said stored segment reaches said maximum length which causes a back force in the length of band between said drum and accumulator, resulting in a non-frictional loose engagement of said convolutions with said drum''s periphery and preventing further feeding to said accumulator.

2. A feed device as defined in claim 1, wherein said accumulator means consist of upper and lower strap guide means through which said segment of the strapping band is threaded to form a variable length loop configuration, means for mounting said upper strap guide means above said lower strap guide means, and track means for guiding said lower strap guide means in a straight path towards and away from said upper strap guide means, wherein said lower strap guide means moves upwardly towards said upper strap guide means as said segment of the strapping band decreases towards said minimum length.

6. A feed device for supplying a continuous length of strapping band to a strapping machine, comprising a frame member, a first drive shaft rotatably mounted on said frame member and carrying a supply reel adapted to hold a continuous length strapping band, a second drive shaft rotatably mounted on said frame member adjacent to said first drive shaft and carrying a cylindrical drum, means mounted on said frame member for guiding the strapping band around the periphery of said drum to form at least two spaced spirally-wound convolutions, means for driving said drum, and accumulator means supported by said frame member to store a variable segment of the strapping band for providing a constant supply of the strapping band to a strapping machine, wherein said drive means intermittently feeds the strapping band to said accumulator means at a greater rate than the withdrawal rate of strapping band from said accumulator.