US3494163A

US3494163A - Automatic coiling apparatus

Info

Publication number: US3494163A
Application number: US679451A
Authority: US
Inventors: Edward M Wight
Original assignee: Tracor Inc
Current assignee: Tracor Inc; Tracor Aerospace Austin Inc
Priority date: 1967-10-31
Filing date: 1967-10-31
Publication date: 1970-02-10
Anticipated expiration: 1987-02-10

Description

Feb. 10,1970 v} 3,494,163

AUTOMATIC 001mm APPARATUS Filed Oct. 51, 1967 i 2 Shet s-Sheet 1 fa wara 1/. M A

' INV EN TOR 11 TTOR NE YS Feb. 10, 1970 1 v I s. MWKGHT 3',

AUTOMATIC COILII IG APPARATUS File d Oct. 51, I967 4 z Sheefs-Shet? Edward M 14096? INVENTOR /1 TTOR NE YS United States Patent O 3,494,163 AUTOMATIC COILING APPARATUS Edward M. Wight, Austin, Tex., assignor to Tracor, Inc., Austin, Tex., a corporation of Texas Filed Oct. 31, 1967, Ser. No. 679,451 Int. Cl. B21c 47/04 US. Cl. 72-129 Claims ABSTRACT OF THE DISCLOSURE Apparatus for automatically coiling strips of metal foil. The apparatus includes a first portion for crimping, metering and shearing a continuous strip of foil and a second portion for coiling the sheared foil strips including a bobbin and a plurality of pivotally mounted contact arms biased to contact the perimeter of a coil as the coil is wound on the bobbin. A first drive means is provided for the first portion which is controlled by a programed control unit. A second drive means is provided for the bobbin of the second portion. Control means synchronizes the operation of the second drive means to the operation of the first drive means. The first portion is mounted on a vertically oriented and vertically movable first platform, and the second portion is mounted on a vertically oriented and pivotally movable second platform. Control means are provided to decrease the speed of the second drive means as the diameter of a coil being wound on the bobbin increases and when the second platform is pivotally rotated towards the first platform. Means are also provided to move the first platform vertically as the diameter of a coil being wound on the bobbin increases. Further, means are provided to stop operation of the first drive means when the first platform moves vertically a predetermined distance.

BACKGROUND OF THE INVENTION This invention relates generally to automatic devices, and in particular to a device for automatically packaging strips of metal foil.

Thin strips of metal foil, referred to as chaff, have been used as a radar counter measure since World War II. According to the Encyclopaedia Britannica, aluminum foil cut into strips about half a wave length long and at the radar frequency was commonly used during World War II to give false echos when dispersed from aircraft. Typically, the strips are on the order of 50 mils wide and less than 1 mil thick. The length depends on the radar frequency, which according to the Encyclopaedia Britannica may be 1 or 2 centimeters to a few meters.

At shorter wave lengths, from 1 to or centimeters for example, the packaging of the foil does not present much of a problem since the strips are relatively short. Strips less than 10 centimeters in length are commonly packaged in bales with the foil strips in parallel axial alignment. However, longer strips, over 20 centimeters in length for example, lack the axial rigidity or stiffness to be packaged in this manner.

A novel chaff package has been devised for the longer chaff wherein the foil strips are coiled rather than baled. In this package the strips are wound on the coil with each strip overlapping the succeeding strip. While the package is technically successful, hand packaging techniques have been too expensive to make the package economically feasible.

The present invention is a device for automatically packaging metal foil in a coil package. With this device, foil can be economically packaged at an increment of the cost of packaging by hand techniques.

SUMMARY OF THE INVENTION In accordance with this invention, the packaging device includes a crimping and metering portion which is mounted on a vertically movable and a vertically oriented platform and a packaging portion which is horizontally movably mounted on a second vertically oriented platform.

In the crimping and metering portion, a foil strip is passed through crimper wheels which crimp the foil and thus increase the axial stiffness of the foil. The crimper wheels may also provide the motivation to the foil as it is taken from a supply source and passed to the packaging portion. After leaving the crimper wheels, the foil passes through a shearing mechanism which shears the foil after a desired length of foil is metered out.

The packaging portion includes a bobbin on which the foil strips are wound. A plurality of contacting arms are provided to retain the foil on the bobbin as the coil is wound.

Drive means which is operated by a programmed control unit is provided for the crimper wheels and shearing mechanism. Drive means is also provided for the bobbin along with control means for synchronizing the operation of the bobbin drive means to the operation of the crimper wheel drive means. The control means also varies the bobbin speed as the coil on the bobbin increases in diameter.

The packaging platform is horizontally or pivotally movable so that when the bobbin speed exceeds the foil strip speed, such as during acceleration of the crimper wheels, the platform and bobbin are moved towards the crimping and metering portion. Means are provided to reduce the bobbin speed whenever the packaging platform is moved from its normal position.

Because of the relative flexibility of the foil strips, it is critically important that the foil strips contact the coil tangentially during the packaging process. Means are provided to move the crimping and metering support platform vertically as the coil package increases in size, thereby maintaining the tangential relationship of the strip to the coil.

The invention will be more fully understood from the following description and appended claims when taken with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an isometric view of a typical strip of metal foil or chaff.

FIGURE 2 is a view of metal strip just as it is to be wound on a partially filled package.

FIGURE 3 is a plan view of apparatus in accordance with this invention.

FIGURE 4 is a schematic diagram of apparatus in accordance with the invention.

FIGURE 5 is a schematic diagram of the voltage controlled oscillator of FIGURE 4.

FIGURE 6 is a schematic diagram of the vertical servo mechanism of FIGURE 4.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS Before proceeding with the description of the illustrative embodiments of the present invention, a brief description of the metal foil and coil package will be helpful. FIGURE 1 is an isometric view of a typical strip of metal foil. As described above, the foil strip 1 is of the order of 50 mils wide, less than 1 mil thick, and from less than 1 centimeter to over 1 meter in length. The strip is crimped to increase its stiffness or resistance to bending stresses. However, because of the small width and thickness dimensions, longer strips are easily bent even when crimped.

To overcome the problem of packaging the longer strips, the coil package has been devised. The strips are wound on the coil with each strip overlapping the succeeding strip as shown in FIGURE 2. In FIGURE 2, coil 5 includes strip 6 which is partially wound on the coil. Contacting arm 7, partially shown, retains strips 6 on the coil and provides a stop for the end portion of the strip which is spring biased against the stop. Strip 9, shown about to be wound on the coil, is moved tangentially to the coil and overlapped by the end portion of strip 6. Because of the susceptibility of the strip to bending, it is critical that the incoming strip remains tangent to the coil. Thus, since the coil increases in size as the coil is wound, the foil must be moved vertically to maintain the strip in tangential alignment with the coil.

Referring now to FIGURE 3, a plan view of one embodiment of the automatic coiling apparatus is shown. The apparatus includes a crimping and metering portion and a packaging portion 16.

The crimping and metering portion 16 includes a vertically movable supporting platform 20 on which is mounted crimping wheel 21, backup wheel 22 and shearing mechanism 23.

The packaging portion 16 includes a rotatable supporting platform 25 on which are mounted bobbin 26 and a plurality of movable contact arms 27.

The crimper Wheel 21 and backup wheel 22 of the crimping and metering portion are driven by suitable drive means and pull foil strip 30 from a foil roll 39 over

guide rollers

31, 32, 33 and 34. Roller 35 which is mounted on movable rod 36 functions to take up slack in the foil strip as the crimper wheel 21 and backup wheel 22 are stopped and started.

The crimping wheel 21 crimps the strip of foil as shown in FIGURE 1, and pushes the crimped strip through shearing mechanism 23 to the coil 38 on bobbin 26.

A conventional tape control means is provided for controlling the operation of the drive means for the crimper wheel 20, backup wheel 22, and shearing mechanism 23. For example, the mill machine control, Model No. TCIR 1008 manufactured and sold by the Superior Electric Company is suitable.

A drive means is provided for the bobbin 26 in the packaging portion 16, and a control means is operably connected with the drive means for the crimper wheel 21 to synchronize the operation of the two drive means. The control means also decreases the bobbin speed as the coil 38 on the bobbin 26 increases in diameter.

The drive means and control means constitute a closed loop servo system, whereby the bobbin 26 seeks a perfect velocity match with the crimper wheel 21. The bobbin is provided with greater acceleration than the crimper wheel 21 because there can be no compression stresses in the foil during start-up. It is preferable to always maintain a slight tension in the foil.

In the illustrated embodiment the packaging platform 25 is rotatable so that when the bobbin speed exceeds the coil strip speed the bobbin 26 is moved horizontally to ward the crimping and

backup wheels

21 and 22 respectively. However, the platform 25 could be supported on on rollers so that the entire platform is horizontally movable. Means are provided to reduce the speed of bobbin 26 whenever the packaging platform 25 is rotatably moved from its normal position, thereby achieving the velocity match between the bobbin 26 and the crimper Wheel 21.

FIGURE 4 is a schematic diagram of the apparatus in FIGURE 3 showing the drive means and various control means. Stepping motor 40 drives backup wheel 22 and crimper wheel 42 through the gear train shown generally at 43. Stepping motor 40 and solenoid 45 which operates shearing mechanism 23 are controlled by a tape control unit (not shown). Gear train 43 also drives a DC. generator 48 which forms part of the control means for stepping motor 49 which drives bobbin 26 through means of belt drive 51. The DC. voltage output of generator 48 is connected through potentiometer 54 to a voltage controlled oscillator 55. Potentiometer 54 is geared to contact arm 27 which contacts the perimeter of coil 38 on the bobbin 26 so that the movable arm of potentiometer 54 changes position as the coil increases in diameter. Operation of the potentiometer 24 will be more fully described below with reference to the voltage controlled oscillator shown in FIGURE 5.

Packaging platform 25, shown partially in section and which is pivotally mounted by pin 61, is normally maintained in a position abutting stop 62 by means of spring 63. Pivotal movement of the platform toward shear mechanism 23 changes the position of the movable arm of potentiometer 64 through means of rack and pinion 65. Operation of potentiometer 64, which is electrically connected to the voltage controlled oscillator 55, will be described below with reference to FIGURE 5.

Voltage controlled oscillator 55 produces a pulsed voltage output with the pulse rate being a function of the speed of drive motor 40, the position of contact arm 27 which senses coil diameter, and the position of platform 26 which are measured by means of generator 48, potentiometer 54 and potentiometer 64, respectively. The pulse rate of the output voltage of the voltage controlled oscillator 55 controls the speed of stepping motor 49 whose speed is a function of the pulses per second of the control voltage applied thereto.

Contact arm 27 is also geared to potentiometer 68 which is operably connected to servo amplifier 69 for servo-motor 70. The servo-motor 70 drives vertical lead screw 71 which moves the crimper and meter platform 20 (shown partially in section) vertically. As the diameter of coil 38 increases, the setting of potentiometer 68 is changed and servo-motor 70 is energized and raises platform 20 by means of the vertical lead screw 71. Thus, the coil strip 74 is maintained at a tangent to the coil 38 as the coil increases in diameter.

When coil 38 is full, platform 20 contacts microswitch 75 which blocks further operation of stepping motor 40.

FIGURE 5 is a schematic diagram of the voltage controlled oscillator 55 in FIGURE 4. The positive terminal of generator 48 is connected to a positive supply voltage terminal +V. The negative terminal of generator 48 is serially connected through potentiometer 54 to the +V supply terminal. The movable arm of potentiometer 54 is connected to the base of PNP transistor 82. The emitter of the transistor 82 is connected through resistor 83 and potentiometer 64 to the -]V supply terminal. The collector of transistor 82 is coupled to ground through capacitor 85, and the collector is also connected to the emitter electrode of unijunction transistor 86. One base electrode of unijunction transistor 86 is connected serially through resistors 87 and 88 to the +V supply terminal, and the other base electrode of the unijunction transistor 86 is connected through resistor 89 to ground and to the base of transistor 90 through resistor 94. A Zener diode 91 shunts resistor 87, unijunction transistor 86 and resistor 89, with the anode of diode 91 connected to ground. The emitter of NPN transistor 90 is connected to ground and the collector is connected through resistor 92 to the cathode of diode 91 and the common terminal of resistors 87 and 88. The oscillator output terminal 93 is connected to the collector of transistor 90.

In operation, transistor 82 is turned on by the voltage from potentiometer 54 when generator 48 produces a DC. voltage. The conductivity of the transistor 82 depends on the voltage output of the generator 48 and the setting of the contact arm of the potentiometer 54. When transistor 82 is conducting, a current flows through potentiometer 86, resistor 83 and transistor 82 and charges capacitor 85, the charging current depending on the setting of potentiometer 64 and the conductivity of transistor 82. The voltage accumulated on capacitor triggers unijunction transistor 86 and a positive voltage is developed at the base of the unijunction transistor 86 which forward biases NPN transistor 90 through current limiting resistor 94. The charge on capacitor 85 drains through the unijunction transistor 86 until an insufficient charge remains on the capacitor 85 to maintain the conducting state of transistor 86. The unijunction transistor 86 then becomes nonconductive until the capacitor 85 recharges.

The voltage at the output terminal 93 of the oscillator is positive when transistor 90 is not conducting. However, when the transistor 90 receives the positive voltage from unijunction transistor 86 and becomes conductive, the output voltage drops to near ground potential. Thus, the triggering of transistor 90 develops a pulsed voltage at output terminal 93, the pulse rate depending on the voltage generated by generator 48 and the settings of

potentiometers

54 and 64. Zener diode 91 maintains a constant level positive voltage for the output terminal 93.

FIGURE 6 is a schematic diagram of the vertical servo mechanism which moves the crimping and metering platform 20 vertically in response to changes in the coil diameter. Potentiometer 68 is connected between +V supply terminal and ground. The movable arm of the po tentiometer 68 is connected through resistor 101 to one input terminal of amplifier 102, the other input terminal of the amplifier being grounded. Potentiometer 105 is connected through resistor 106 and variable resistor 107 to a V supply terminal. The movable arm of potentiometer 105 is connected through resistor 108 to the first input terminal of amplifier 102. Capacitor 109 is connected between ground and first terminal of amplifier 102. The amplifier 102 drives servo-motor 70. Motor 70 drives the vertical lead screw 71 which moves the crimping and metering platform 20 and also the wiper arm of potentiometer 105.

In operation, the wiper arm of potentiometer 68 moves vertically as a coil being wound increases in diameter. This is accomplished by contact arm 56 of FIGURE 4 which is geared to the wiper arm of potentiometer 68. The increased positive voltage on the wiper arm is transmitted through resistor 101 to amplifier 102 which then drives servo-motor 70 and raises the platform 20. The motor 110 also moves the wiper arm of potentiometer 105 vertically and increases the negative voltage on the wiper arm until the increase in negative voltage returns the voltage on the first input terminal of amplifier 102 to zero. At this time the motor 110 is turned off. Thus, the foil strip being wound on the coil is maintained at a tangent to the coil by means of this servo mechanism while the coil is being wound.

As stated above with reference to FIGURE 2, the packaging platform 25 can be horizontally movable as well as pivotally movable so long as the bobbin 26 is movable towards the metering portion 15. Also, while the

platforms

20 and 25 are described as vertically oriented, other orientations can be provided. Thus, while the invention has been described with reference to specific embodiments, the description is illustrative and is not to be construed as limiting the scope of the invention. Various modifications and changes may occur to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. Apparatus for coiling strips of foil comprising a first portion including means for pulling a strip of foil from a supply source and means for shearing said strip of foil into desired lengths, and

a second portion including a bobbin on which said strips of foil are wound and a plurality of movable contact arms biased to engage the perimeter of a coil as the coil is wound on the bobbin,

said first portion is mounted on a vertically movable and vertically oriented platform and said second portion is mounted on a movable vertically oriented platform.

2. Apparatus for automatically coiling strips of foil comprising a vertically movable and vertically oriented first platform,

a first portion mounted on said first platform for metering, crimping and shearing,

a continuous strip of foil including rollers for metering and crimping said continuous strip of foil,

drive means for said rollers, and

means for shearing said foil in strips,

a horizontally movable and vertically oriented second platform,

a. second portion mounted on said second platform for coiling the foil strips including a bobbin, drive means for said bobbin, and a plurality of movable contact arms biased to engage a coil as the coil is wound on the bobbin, automatic control means for said drive means for said rollers and said means for shearing said foil, and control means for synchronizing the operation of said drive means for said bobbin to the operation of said drive means for said rollers.

3. Apparatus in accordance with claim 2 and further including sensing means for sensing the diameter of a coil as said coil is wound on said bobbin, and

means responsive to said sensing means for moving said first platform vertically as said coil increases in diameter.

4. Apparatus in accordance with claim 3 and further including means for stopping operation of said first drive means when said first platform is moved vertically a predetermined distance.

5. Apparatus in accordance with claim 2 and including means for sensing the diameter of a coil as said coil is wound on said bobbin, and wherein said control means decreases the speed of said drive means for said bobbin as the diameter of a coil on said bobbin increases and as said second platform is moved horizontally towards said first platform.

6. Apparatus for automatically metering out and crimping a continuous foil strip, shearing said strip into desired lengths and winding said foil strips into a coil comprising a first portion for metering, crimping and shearing the continuous strip of foil including,

rollers for metering and crimping said continuous foil strip, first drive means for said rollers, means for shearing said foil into said strips, and a vertically oriented and vertically movable first platform on which said rollers, said first drive means and said means for shearing are mounted, a second portion for coiling said strips including a bobbin, second drive means for said bobbin, a plurality of movable contact arms biased to engage a coil as the coil is Wound on the bobbin, and a vertically oriented and horizontally movable second platform on which said bobbin, said second drive means and said plurality of contact arms are mounted, and control means for synchronizing the operation of said second drive means to the operation of said first drive means.

7. Apparatus in accordance with claim 6 and further including sensing means for sensing the diameter of a coil as said coil is Wound on said bobbin, and

8. Apparatus in accordance with claim 6 and including means for sensing the diameter of a coil as said coil is wound on said bobbin and wherein said control means decreases the speed of said second drive means as the diameter of a coil on said bobbin increases and decreases the speed of said second drive means as said second platform is moved horizontally toward said first platform. V

9. Apparatus in accordance with claim 8 and further including means for stopping operation of said first drive means when said first platform has moved vertically a predetermined distance.

10. Apparatus in accordance with claim 6 wherein said second drive means includes a stepping motor the speed of which is proportional to the pulses per second of the electrical voltage applied thereto, and

References Cited UNITED STATES PATENTS 3/1942 Nyberg 72146 12/1967 Properzi 72l48 LOWELL A. LARSON, Primary Examiner US. Cl. X.R.