US3244380A

US3244380A - Coil handling apparatus

Info

Publication number: US3244380A
Application number: US331741A
Authority: US
Inventors: Hoyne Benjamin Luke
Original assignee: American Can Co
Current assignee: Primerica Inc
Priority date: 1963-12-19
Filing date: 1963-12-19
Publication date: 1966-04-05
Anticipated expiration: 1983-04-05

Description

April 5, 1966 B. 1 HOYNE 3,244,380

COIL HANDLING APPARATUS Filed Dec. 19, 196.3 2 Sheets-Sheet l BYgM April 5, 1966 B. L. HOYNE COIL HANDLING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 19, 1963 INVENTOR, flf/Vf/lM/A/ (UK f HOV/I6.

United States Patent 3,244,380 COIL HANDLING APPARATUS Benjamin Luke Hoyne, Lyndhurst, N..I., assignor to American Can ompany,'New York, N.Y., a corporation of New Jersey Filed Dec. 19, 1963, Ser. No. 331,741 8 Claims. (U. 242-786) The present invention rel-ates generally to apparatus for handling coil stock and more particularly to apparatus for preventing damage to a coil of sheet metal stock when it is mounted on the expanded jaws of a supporting mandrel by automatically reducing the outward pressure of the jaws disposed within the core of the coil when the thickness of the coil is decreased to a predetermined dimension.

In the feeding of coils of sheet metal stock, such as tin plate, to cutting or other type equipment, a rotatable mandrel normally is disposed within the core of each coil and is provided with expansible jaws in firm contact with the interior surface of the coil so that it will rotate with the mandrel. 'Because of the tremendous weight of a coil of sheet metal stock (approximately 16,500 lbs. for the average coil of tin plate to be used in making cans), it is necessary that high fluid pressures of about 700 lbs/sq. in. be utilized to expand the jaws against the interior surface of the coil in order to prevent slippage between the coil and the jaws.

After a substantial portion of the coil is fed to the cutting equipment to thus reduce both the weight and thickness of the coil, it has been found that the high pressure utilized to expand the jaws against the coil forces the thinned coil to expand unevenly to cause deformation and consequent spoilage of the stock adjacent the coil core. This deformation normally occurs when the coil is decreased to a thickness of approximately one inch or less. The specific thickness at which the undesirable coil deformation begins and the extent of the damage to the stock adjacent the coil core for a given coil thickness is, of course, dependent on the weight of the sheet material in the coil.

In order to prevent this deformation and consequent spoilage of the stock adjacent the coil core, the present invention contemplates novel apparatus for automatically reducing the fluid pressure on the mandrel jaws when the coil is decreased to a thickness of approximately one inch. This is accomplished by providing a photoelectric cell and a light source in alignment therewith on opposite sides of the coil and so positioned that the coil cuts off the light source from the photo-electric cell until the thickness of the coil is decreased to approximately one inch. When the coil thickness is so decreased, the light source energizes the photo-electric cell to supply current to an amplifier connected thereto. The amplifier in turn energizes a control solenoid for a valve in the fluid supply line connected to the jaw expanding mechanism. The energization of the solenoid opens the valve to bring a pressure reduction valve into communication with the fiuid supply line to reduce the pressure therein to approximately 40 lbs/sq. in. This reduction in pressure reduces the force of the jaws on the thinned coil sufficiently to prevent the above described deformation and resulting spoilage of the coil stock adjacent the coil core, while firmly retaining the thinned coil on the mandrel.

It is an object of the present invention, therefore, to provide apparatus for handling coils of sheet metal stock in a manner to prevent damage to the stock.

Another object is the provision of rotatable apparatus which is insertable into the core of a coil of sheet met-a1 stock and expansible under adjustable pressure into firm contact with the interior of the coil so that the coil may be rotated therewith to feed the sheet metal stock to cutting or other type equipment.

A further object of the present invention is to provide such an apparatus wherein the outward pressure thereof on the interior of the coil is automatically reduced when the coil is decreased to a predetermined thickness to thus prevent deformation and consequent spoilage of the sheet metal stock adjacent the coil core.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

FIGURE 1 is a side elevational view of the apparatus constructed according to the principles of the instant invention, showing a coil of sheet metal stock mounted on the instant apparatus and being fed between a pair of feed rolls;

FIG. 2 is a sectional view taken substantially along line 22 of FIG. 1, with parts broken away, and showing in schematic form the electrical, mechanical and fluid control system for controlling the holding or mandrel jaw pressure on the interior of a coil mounted on the instant apparatus;

FIG. 3 is an enlarged elevational view of a portion of the apparatus shown in FIG. 1, with parts broken away, showing a coil of sheet metal stock after it has been decreased to a predetermined thickness and after the holding pressure of the mandrel jaws on the interior portion thereof has been reduced to prevent deformation of the coil stock adjacent the core thereof; and

FIG. 4 is a view similar to FIG. 3, showing the de formation and consequent spoil-age of the sheet metal stock adjacent the coil core when the outward or holding pressure of the mandrel jaws is not reduced as the coil thickness is decreased to a predetermined dimension.

As a preferred and exemplary embodiment of the instant invention, FIG. 1 illustrates a coil supporting and feeding apparatus 10' comprising -a supporting frame 11 having a base 12 on which there is adjustably mounted a bracket 14. The bracket 14 supports a suitable light source such as an incandescent or vapor type lamp which is connected to a suitable source of power by wires 17. The light source 16 is so mounted on the bracket 14 that its light beams L are directed substantially upwardly for a purpose to be described more fully hereinafter.

Extending upwardly from and rigidly secured to the frame :base 12 are a pair of substantially parallel frame members 18 and 20 which are integrally connected by a substantially horizontal frame member 21 (see FIG. 2). Rigidly mounted on the horizontal frame member 21 and extending upwardly therefrom is an auxiliary frame 22 having a. bracket 24 (FIG. 1) adjustably mounted on the upper portion thereof. The bracket 24 preferably supports a light [responsive photo-emissive device such as a photo-electric cell 26 which is in substantial alignment with the light beams L from the light source 16. The photo-electric cell 26 is connected by conductors 2'7 to a control circuit which will be described hereinafter.

A rotatable, hollow, coil-supporting mandrel 28 having expansible curved jaws 30 of identical construction mounted thereon and evenly spaced therearound is dis posed within the core 32 of a coil C of sheet metal stock S. The jaws '30 are expanded into firm contact with the interior surface of the coil C and are rotated with the mandrel 28 to feed the sheet stock S from the coil C to a pair ofguide or feed rolls 34 or other suitable means for directing the sheet stock S toapparatus for cutting or performing some other operation on the stock S.

The light source 16 and photo-electric cell 26 preferably are so disposed with respect to the mandrel 2S and coil C mounted thereon that the coil C is normally disposed between the light source 16 and photo-electric cell 26 to prevent energization of the cell 25 .by the light source 16 until the coil C is decreased to a predetermined radial thickness, e.g., approximately one inch, the purpose of which will be fully apparent from the description heretin after.

Referring now to FIG. 2, the hollow mandrel 23 is rotatably mounted in bearings 3d and 38 which are integral with the frame members 13 and Zll, respectively. The frame members 13 and 20' are also provided with bearings 4i and 42, respectively, in which there is rotatably mounted a drive shaft 44 which is driven by any suitable drive means such as a motor (not shown). A driving gear 46 is rigidly mounted on the drive shaft 44 between the bearings 40 and 42 and is in engagement with a driven gear 48 which is bolted to a radially extending flange Q rigidly mounted on the mandrel 28. The rotation of the mandrel 23, therefore, is controlled by the drive shaft 54 and the drive means for the latter.

A second radially extending flange 52 is rigidly mounted on a portion of the mandrel 28 which is disposed within the coil core 32. Each of the expansible jaws 34B is provided with a recess 54 in radial alignment with the radially extending flange 52 so that the latter is receivable therein. A pair of depending arms 56 are provided on each of the jaws 3t? and are disposed on opposite sides of the flange 52. Laterally extending rods 58 are rigidly supported at one end on the depending arms 56 and are rigidly secured at the other end to a pair of depending jaw arms (not shown) in lateral alignment with and identical in construction to the pair of depending arms 55. An anti-friction roller 66 is rotatably mounted on each of the laterally extending rods 58 and is in contact with the adjacent surface of the radially extending mandrel flange 52. The flange 52, therefore, serves the purpose of preventing axial movement of the jaws 3G with respect to the mandrel 28 and thus limits the movement of the jaws 3b to inward or outward radial movement with respect to the mandrel 2%. The anti-friction rollers 619' in engagement with the sides of the. lange 52 reduce the friction between the flange 52 and the jaws 3% so that the jaws 3d are freely movable in a radial direction.

Slidably mounted on the outer, reduced diameter end 61 of the mandrel 28 disposed within the coil core 32 is a cylindrical slide member 62 having three radially extending arms 64 equally spaced on the periphery thereof. Each of the arms 64 terminates in a radially or laterally extending, oblique guide or wedge member 66 which is slidably disposed in a correspondingly oblique dovetailed guide slot 68 provided in a radially inwardly extending portion 7% on the adjacent jaw 31 As shown in FIG. 1, the mutually engaging wedge or eam faces of the member 66 and slot 68 are arcuate in cross-section.

The slide member 62 is provided with three radially extending trunnions 72 equally spaced on the periphery thereof which are in axial alignment with three radially extending trunnions 72 equally spaced on the periphery of a second slide member 76 which is annular in con figuration and slidably mounted on the mandrel 28. Tie rods '78 are disposed between the trunnions '72 and '74 and extend through apertures 79 in the radial mandrel flange 52. Each of the tie rods 78 is provided with threaded end portions 89 which extend through the adjacent trunnions "1'2 and '74, and nuts 82 are threaded on the end portions 80 to secure the trunnions' 72 and 74 and thus the slide members 62 and 76, respectively, on the tie rods 78. It will be readily seen that, because of the tie rods 78, the slide members 62 and 76 are axially slidab-le in unison on the mandrel 28 and there can be n axial movement of one slide member independently of the other. Also, the slide members 62 and 76 are rotatable in unison with the mandrel 28 since the tie rods 78 extend through the apertures 79 in the mandrel flange 4 52 so that they are rotated therewith and thus in turn rotate the slide members 62 and 76.

The slide member 76 is provided with three radially extending arms 84 equally spaced on the periphery thereof and in alignment with the mandrel jaws 30. Each of the radial extending arms 84 terminates in a radially or laterally extending, oblique guide or wedge member 86 which is slidably disposed in a correspondingly oblique, lovetailed guide slot 88 provided in 21 depending portion 96 of the adjacent jaw 3d. The members and slots 89 are similar in construction and function to the previously described members 66 and slots 68. Because of the obliqueness of the guide slots 68 and 88 and the respective guide members 66 and so disposed therein, axial movement of the slide members 62 and 76 on the mandrel 28 results in radial movement of the jaws 30 with respect to the mandrel 28. Thus, when the slide members 62 and 76 are moved axially towards the supporting frame 11 (to the right as seen in FIG. 2), the jaws 30 are moved radially outwardly into firm contact with the interior surface of the coil C mounted thereon. In order to properly position the coil C on the jaws 34 a radially extending flange 91 is provided on the outer surface of each of the jaws 30 and is in contact with the adjacent portion of the coil C.

The slide members 62 and 76 are moved axially on the mandrel 28 by a shaft 92 extending longitudinally or axially through the mandrel 28 and having one end thereof provided with a threaded portion 94 which extends through an aperture 9:: in the slide member 62 and is secured thereto by a nut 98. The other end of the shaft 92 is rigidly secured to a piston rod 165! that is in turn secured to a piston 1412. The piston 102 is slidably disposed in a hydraulic cylinder 104 that is rigidly secured to a supporting bracket 1% that in turn is bolted to the frame member 20 of the supporting frame 11.

A pair of fluid supply lines 108 and 1119 are connected at one end to the cylinder 104 and at the other end to a reversing valve 112 of conventional construction having an operating lever 113. A fluid conduit 114 extends from the reversing valve to a fluid reservoir 115 of any suitable or conventional type, and a second conduit 118 extends from the reversing valve 112 to a pressure reducing valve 120. A thirdconduit 122 connects the pressure reducing valve to a pressure producing device such as a highpressure pump P which in turn is brought into communication with the reservoir 116 through a conduit 124. The pump-P is of conventional construction and is driven by any suitable drive means such as a motor M, and may be capable of producing hydraulic pressures of 1500 lbs./

sq. in.

A fifth conduit 126 is connected at one end to the third conduit 122 and is connected at the other end to a second pressure reducing valve 128. The pressure reducing valve 128 is connected by a sixth conduit 129 to a control device or piston valve 139 which in turn is connected to the conduit 114 by a seventh conduit 131. The piston valve 130 comprises a piston 132 which is slidably mounted in a valve housing 133 and connected to a movable core 134 of a control solenoid 136. The piston 132 is normally maintained in the position shown in FIG. 2, wherein it cuts off the sixth conduit 129 from the seventh conduit 131, by a spring 138 surrounding the movable core 134 and disposed between the piston 132 and the upper end of the valve housing 133. The control solenoid 136 is connected by conductors 1449 to an amplifier and powersupply unit 142 of conventional construction which in turn is connected-tothe photo-electric cell 25 by conductors 27.

The just described hydraulic system is filled with a hydraulic fluid of any suitable type.

In operation, when the operating lever 113 of the reversing valve 112 is in the position shown in FIG. 2,

the feed line 168 is connected through the valve 112 to the conduit 114 leading to the reservoir 116, and the feed line 110 is connected through the valve 112 to the second conduit 118 leading to the pressure reducing valve 120. As an illustrative example, the pump P preferably is operated to create a pressure in excess of 700 lbs./ sq. in. in the third conduit 122 connected to the pressure reducing valve 120. The pressure reducing valve 120 preferably is constructed'to convey pressures of 700 lbs./ sq. in. or less, if the pressure in the system be less, to the second conduit 118 connected to the reversing valve 112. Since the pump P creates a pressure in excess of 700 lbs./ sq. in. in the third conduit 122, the pressure reducing valve 120 passes a'pressure of 700 lbs/sq. in. to the second conduit 118, which pressure is conveyed through the second conduit 118, the reversing valve 112 and the feed line 110 to the interior of the cylinder 104. The pressure of 700 lbs/sq. in. in the cylinder 104 moves the piston in a direction away from the feed line 110 (to the right as seen in FIG. 2).

The shaft 92 connected to the piston rod 100 is thus moved axially or longitudinally within the mandrel 28 in a direction the same as that of the piston 102 to thereby axially move the slide members 62 and 76 on the mandrel 28 to the position shown in FIG. 2. When the slide members 62 and 76 are so moved, the wedging or camming action of the oblique guide members 66 and $6 in the corresponding guide slots 68 and 88, respectively, causes the jaws 30 to move radially outwardly on the mandrel flange 52 into firm engagement with the interior surface of the coil C mounted thereon. Because of the tremendous weight of a coil of sheet metal stock, it is desirable that a relatively high pressure of approximately 700 lbs./ sq. in. be applied to the piston 102 in cylinder 104, and thus through the shaft 92 and slide members 62 and 76 to the jaws 30, so that the coil C will be firmly engaged by the jaws 30 and rotated with the mandrel 28 in order to feed the sheet metal stock S thereof. It is for this reason that the pressure reducing valve 120 preferably is constructed to pass pressures of up to 700 lbs./ sq. in. It is noted, however, that the maximum pressure passed by the pressure reducing valve 120 and thus that applied to the piston 102 will necessarily vary with the size of the coil C and the type of sheet metal stock S mounted on the coil supporting and feeding apparatus 10. The recited holding pressure of 700 lbs/sq. in., therefore, is merely illustrative and is not meant to limit the present invention.

- As the mandrel 28 is rotated by the drive shaft 44 to feed the sheet stock S from the coil C to the feed or guide rolls 34, the thickness and thus the mass of coil C is gradually decreased. It has been found that under a holding pressure of approximately 700 lbs/sq. in. exerted by the jaws 30 on the interior of the coil C, the sheet metal stock S adjacnt the coil core tends to be creased or deformed when the thickness of the coil C is reduced to approximately one inch or less, depending on the type of sheet metal stock S. This deformation of the coil stock C on a thinned coil S is illustrated in FIG. 4, wherein relatively heavy creases 146 are shown as being formed in thesheet metal stock S when the coil C is decreased to a thickness of approximately one inch or less and is still under an internal holding pressure of approximately 700 lbs/sq. in. exerted by the jaws 30. These heavy creases 146 are undesirable since they result in a downgrading or spoilage of the stock S remaining in the thinned coil C. In addition to the creases, under some circumstances actual stretching of the stock in the coil C may be encountered when the initially high holding pressures are exerted against a thinned coil.

This undesirable deformation of the coil stock S in the thinned coil C is prevented by the present invention. As shown in FIGS. 1' and 2, when the coil stock .C is decreased to a predetermined thickness of approximately one inch, the coil C no longer is interposed between the light source 16 and the cell 26 and the photo-electric cell 26 is exposed to the light source 16. The photo-electric cell 26 thus is energized to generate an electrical impulse which is amplified by the amplifier and power supply unit 142 to energize the control solenoid 136. The movable solenoid core 134 thus is moved upwardly and the valve piston 132 connected thereto is moved against the force of the spring 138 to open the valve 130 and connect the sixth conduit 129 and seventh conduit 131, thereby open ing a low-pressure by-pass circuit in the hydraulic system. The second pressure reducing valve 128, therefore, is connected to the conduit 114 leading to the fluid reservoir 116. a

The pressure reducing valve 123 preferably is constructed to pass relatively low pressures of approximately 40 lbs/sq. in. or less and thus reduces the pressure in the whole hydraulic system, including the fifth conduit 126, the third conduit 122, the second conduit 118, the feed line 110, the conduit 108 and the conduit 114 to approximately 40 lbs/sq. in. The pressure in the cylinder 104 acting on the piston 102 is similarly reduced to in turn correspondingly reduce the holding pressure of the jaws 30 on the thinned coil C. It is noted that the reduced pressure of 40 lbs/sq. in. is an illustrative example only and that any suitable reduced pressure could be used. This reduction in holding pressure when the coil C is decreased to a predetermined thickness of approximately one inch prevents the undesirable deformation and consequent spoilage of the sheet metal stock S on the thinned coil C, and is sufiicient to retain the thinned coil C on the jaws 30 for rotation with the mandrel 28.

When the sheet metal stock S of the coil C is completely fed to the guide or feed rolls 34, the jaws 30 may be moved radially inwardly to receive a new coil by the manual or automatic shifting of the operating lever 113 of the reversing valve 112 to connect the feed line 108 with the second conduit 118 and to connect the feed line 110 to the conduit 114 leading to the fluid reservoir 116. The pressure in the cylinder 104 acting on the piston 102 is thus relieved through the feed line 110 and transmitted to the reservoir 116, while the feed line 108 conveys fluid pressure from the second conduit 118 to the opposite side of the piston 102 to move it towards the jaws 30 (to the left as seen in FIG. 2).

This reverse piston movement causes the shaft 92 to move in the same direction (to the left as seen in FIG. 2) which in turn results in axial movement of the slide members 62 and 76 on the mandrel 28 to thus move the jaws 30 radially inwardly with respect to the mandrel 28. At this time, the valve 112 may be moved to a third or cut-off position, thus locking the jaws 30 in their inward position.

A new coil C may then be mounted on the jaws 30 in any suitable or conventional manner to again out off the photo-electric cell 26 from the light source 16.

This results in the de-energization of the control solenoid 136 and in the movement of the valve piston 132 by the spring 138 into blocking relation between the sixth conduit 129 and the seventh conduit 131. The pressure reducing valve 128, therefore, is no longer effective since it is not connected to the reservoir 116, and the pressure in the second conduit 118 will again increase to 700 lbs./ sq. in. under the control of the pressure reducing valve 120. When the reversing valve 112 is again moved to the position shown in FIG. 2, the 700 lbs/sq. in. pressure in the second conduit 118 will again be conveyed to the cylinder 104 by the feed line 110 to move the piston 102 to the position shown in FIG. 2, thereby again expanding the jaws 30 into firm contact with the new coil C under a holding pressure of approximately 700 lbs/sq. in. The above cycle in the feeding of the coil stock S from the coil C on the jaws 30 by the rotation of the mandrel 28 is again repeated as hereinbefore described.

It is noted that any suitable mechanism other than the aligned photo-electric cell 26 and light source 16 could be utilized to open the piston valve 139 to reduce the mandrel jaw pressure when the coil C is decreased to a predetermined thickness. For example, a switch actuating or feeler member of any suitable construction could be biased into contact with the exterior of the coil C so as to close a switch and actuate the control solenoid 136 to open the valve 13% when the coil C reaches the predetermined thickness. Also, the valve 13% could be opened or closed mechanically through a suitable control linkage, rather than utilizing the control solenoid 136.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invent-ion or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. Apparatus for handling and feeding a coil of sheet metal stock having a core, comprising:

expansihle members disposed within the coil core and expanded under a first relatively high pressure into firm contact with the interior surface of the coil,

means operatively connected to said expansible members for producing said first pressure, and

a mechanism for preventing damage to the sheet stock remaining on the coil, owing to said first relatively high pressure on said expansible members, when the coil is decreased to a predetermined thickness, comprising:

means for sensing the reduction of the thickness of said coil to said predetermined thickness, and

means connected to said sensing means and said pressure means for reducing said first relatively high pressure on said expansible members to a second relatively low pressure when said coil is decreased to said predetermined thickness.

2. In an apparatus for handling and feeding a coil of sheet metal stock having a core, wherein the coil is supported on a rotatable mandrel having mounted thereon expansible jaws which are disposed within the coil core, means for expanding said jaws under a first relatively high predetermined pressure into firm con-tact with the interior surface of the coil,

a mechanism for preventing deformation of the sheet stock remaining on the coil, ow ng to said first relatively high predetermined pressure on said expansible jaws, when the coil is decreased to a predetermined thickness, comprising:

means connected to said sensing means and said expanding means for reducing said first predetermined pressure on said expansible jaws to a second relatively low predetermined pressure when said coil is decreased to said predetermined thickness.

3. The apparatus of claim 2 wherein said sensing means comprises:

a light source and a light responsive device mounted on opposite sides of said coil and so positioned that said coil is normally disposed therebetween until it is decreased to said predetermined thickness to thereby expose said light responsive device to said light source.

4. The apparatus of claim 2 wherein said expanding means comprises a fluid-operated actuating device opera- ..tively connected to said expansible jaws, and

a system for supplying fluid at said first predetermined pressure to said actuating device. 5. The apparatus of claim 4 wherein said actuating device comprises:

a cylinder, and a piston slidably mounted in said cylinder and operatively connected to said expansible jaws; and

said fluid supplying system comprises:

a fluid reservoir,

first conduit means connecting said reservoir and one end of said cylinder,

a pump connected to said first conduit means for producing a pressure in a portion thereof in excess of said first predetermined pressure, and

a first pressure reducing valve disposed in said first conduit means between said portion thereof and said cylinder for reducing said pump-created pressure to said first predetermined pressure.

6. The apparatus of claim 5 wherein second conduit means connect said reservoir and the other end of said cylinder, and

said pressure reducing means comprises:

a second pressure reducing valve connected to said first and said second conduit means and adapted to pass a pressure equal to or less than said second predetermined pressure, and

a control device disposed between said second reduc ing valve and said second conduit means for normally cutting ofi communication therebetween,

said control device being connected to said sensing means and being responsive thereto to establish communication between said second reducing valve and said second conduit means when the thickness of said coil is decreased to said predetermined thickness.

'7. The apparatus of claim 6 wherein said control device comprises a solenoid-operated valve, and

said sensing means comprises:

a light source and a photo-emissive device mounted on opposite sides of said coil and so positioned that said coil is normally disposed therebetween until it is decreased to said predetermined thickness to thereby expose said photo-emissive device to said light source,

said photo-emissive device being operatively connected to said solenoid-operated valve.

8. Apparatus for handling and feeding a coil of sheet metal stock having a core, comprising:

a rotatable mandrel having mounted thereon expansible jaws which are disposed within the coil core,

a fluid-operated actuating device connected to said expansible jaws for expanding them into contact with the interior surface of said coil,

means for supplying fluid at a first relatively high predetermined pressure to said actuating device to expand said jaws into firm contact with the interior surface of said coil, and

a mechanism for preventing deformation of the sheet stock remaining on the coil resulting from said first relatively high predetermined pressure on said expansible jaws when the coil is decreased to a predetermined thickness, comprising:

means for sensing the reductionof the thickness of said coil to said predetermined thickness, and

means connected to said sensing means and to said fluid supplying means for reducing said first relatively high predetermined pressure on said actuating device to a second relatively low predetermined pressure when said coil is decreased to said predetermined thickness, thereby reducing the force of said jaws on the interior surface of said coil.

References Cited by the Examiner UNITED STATES PATENTS 1,988,255 1/1935 SOons 242-57 X 2,202,563 5/1940 Mikaelson 242-721 X 2,556,149- 6/1951 Talbot 24278.l 2,936,132 5/1960 Tracy 24278.1

MERVIN STEIN, Primary Examiner.

STANLEY N. GILREATH, Examiner.

Claims

1. APPARATUS FOR HANDLING AND FEEDING A COIL OF SHEET METAL STOCK HAVING A CORE, COMPRISING: EXPANSIBLE MEMBERS DISPOSED WITHIN THE COIL CORE AND EXPANDED UNDER A FIRST RELATIVELY HIGH PRESSURE INTO FIRM CONTACT WITH THE INTERIOR SURFACE OF THE COIL, MEANS OPERATIVELY CONNECTED TO SAID EXPANSIBLE MEMBERS FOR PRODUCING SAID FIRST PRESSURE, AND A MECHANISM FOR PREVENTING DAMAGE TO THE SHEET STOCK REMAINING ON THE COIL, OWING TO SAID FIRST RELATIVELY HIGH PRESSURE ON SAID EXPANSIBLE MEMBERS, WHEN THE COIL IS DECREASED TO A PREDETDERMINED THICKNESS, COMPRISING: