US3107870A

US3107870A - Wire feeding apparatus

Info

Publication number: US3107870A
Application number: US793182A
Authority: US
Inventors: Thaddeus S Cetnar
Original assignee: WUNDERLICH SPRING MACHINERY CO
Current assignee: WUNDERLICH SPRING MACHINERY CO
Priority date: 1959-02-13
Filing date: 1959-02-13
Publication date: 1963-10-22
Anticipated expiration: 1980-10-22
Also published as: GB932909A

Description

Oct. 22, 1963 T. s. CETNAR WIRE FEEDING APPARATUS 6 Sheets-Sheet l Filed Feb. l5, 1959 INV ENT OR. mw Qzfzaf' ,BM/Mm $2/ Oct. 22, 1963 T. s. cr-:TNAR

WIRE FEEDING APPARATUS e sheets-sheet 2 Filed Feb. l5, 1959 T. S. CETNAR WIRE FEEDING APPARATUS Oct. 2 2, 1963Y 6 Sheets-Sheet 5 Filed Feb. 13, 1959 INVENTOR. w'fmr BY j Oct. 22, 1963 1'. s. CE1-NAR WIRE FEEDING APPARATUS 6 Sheets-Sheet 4 Filed Feb. 13, 1959 o ct. 22, 1.963

6 Sheets-Sheet 5 Fiied Feb. 13, lse

Oct.v 22, 1963 T. s. cETNAR a WIRE FEEDING APPARATUS v e sheets-sheet e To* 220 v -s Powe-.f sysrfl/ Filed Feb. 13, 1959' United States Patent i 3,107,870 WIRE FEEDING APPARATUS.

Thaddeus S. Cetnar, Lombard, lll., assignor to Wunderlich Spring Machinery Company, Chicago, Ill., a corporation of Iliinois Filed Feb. 13, 1959, Ser. No. 793,182 Claims. (Cl. 242-45) This invention relates to apparatus for feeding flexible material, and llas its most important application in the feeding of semi-rigid materials, such as steel wire or the like, from a roll or bundle, where it is desir-able to feed the material with a fixed degree of tension or slack there- 1n.

One particularly advantageous application of the invention is in machines for fabricating wire products, such as coil springs and the like, where there are usually provided wire feeding `apparatus which unwinds wire from a relatively large and beavy roll of wire mounted on a rotatable reel, and intermittently delivers a fixed, predetermined length of wire to the article-forming mechanism of the machine. The wire feeding apparatus often comprises one or more pairs of separable, rotating pressure rollers between which an unwound portion of the Wire passes and is fed by .the friction between the rollers and the wire. Intermittent feeding of a predetermined length of Wire is obtained, for example, by bringing together the separable pressure rollers for the required time necessary to feed the length of wire required. Obviously, the proper amount of material will not be fed to the article-forming mechanism if slippage occurs lbetween the pressure rollers and the wire, and the prevention of :such slippage has, heretofore, been a problem in many cases, resulting in rthe fabrication of ldefective wire products by the machine involved. The problem of slippage is particularly aggravated by forces developed in the wire which oppose the forward movement of the wire between the pressure rollers, such opposition forces, for example, being caused by friction or other forces opposing the free rotation of the wire roll Isupporting reel. This problem has frequently restricted the weight and hence the size of the rolls of wire which could be used.

It is, accordingly, one object of the present invention to provide apparatus for feeding flexible material, particularly semi-rigid material such as wire, intermittently or continuously in a relatively slack condition by simple and reliable means. Another object of the invention is to provide feeding apparatus which feeds the flexible material involved by force of friction between a movable feeding means and the flexible material and with little or no slippage therebetween, even when the material is supplied in large, heavy rolls which normally would provide a slippage problem due to the factors mentioned above. Still another object of the present invention is to provide feeding apparatus -as just described wherein the flexible material fed to the feeding means is maintained in `a slack condition and under variable feeding rates.

In accordance with one application of the present invention involving the feeding of the flexible material by force of friction, there are provided -a variable speed auxiliary feeding means behind the friction feeding means, and means responsive to the degree of slack or tension in the portion of the flexible material moving toward the friction feeding means for varying the feeding rate of the auxiliary feeding means so as to maintain the latter portion of the flexible material in a substantially slack condition which prevents lor minimizes slippage between the friction feeding means and the flexible material. This combination of means is` useful for lboth continuous or intermittent feeding of the flexible material by the friction feeding means.

3,!.01870 Patented Qct. 22, 1963 ly spaced points, so that the teasing of this portion of the flexible material will raise the same and a reduction in the tension thereof will lower the same. A first means is positioned above the suspended portion of the flexible material, which means is responsive to the raising thereof above a given elevation by increasing the feeding rate of a variable speed feeding means to provide slack in the flexible material. A second means is provided below .the suspended portion of the flexible material which is responsive to the lowering thereof 'below a given elevation by decreasing the feeding rate of the variable speed feeding means to prevent .the complete collapse of the suspended portion of the flexible material.

The aforesaid first and second means are most desirably contact members ad-apted to be engaged by the flexible material when it respectively rises above and falls below the aforesaid upper and lower elevations. `In this embodiment of the invention, the flexible material is most desirably made of lor includes a conductive material which is grounded, so that the contact members are grounded whenever the flexible material touches the same. Ground ing of the upper contact member completes an electrical circuit which progressively increases the feeding rate as long as contact is maintained between the upper contact member and the Iflexible material. When the lower contact member is grounded, another electrical circuit is energized which progressively decreases the feeding rate as long as the flexible material and the lower contact member are in engagement. When the 4flexible material is out of engagement with the contact members, the feeding rate is maintained at. its last adjusted feeding rate. This arrangement will automatica-lly keep the suspended portion of the flexible material in Ia given range of slack determined by the spacing 'between the upper and lower contact members.

The variable speed feeding means most advantageously includes a control member whose position determines the feeding rate of the variable speed feeding means.v The shaft of `a reversible speed control motor having a first input for driving the motor in one direction and a -second input for driving 4the motor in the other direction is coupled .to this control member, and the energization of the first and second inputs to this motor vare respectively controlled by the aforesaid electrical circuits associated with the upper and lower contact members.

With the arrangement just described, where the variable speed feeding means is used in conjunction with a main friction feeding means, the variable speed auxiliary feeding means may -be continuously driven even when the friction feeding means provides `an intermittent -feed of the flexible material. Where the length of flexible material to be intermittently fed by the friction feeding meansvis to be varied due to a change in the size or construction of the article being made, the average feeding rate of the auxiliary feeding means must also vary'. In such case, it has been found desirable to provide variable upper and lower limits -to the feeding rate of the auxiliary feeding means. To this end, a follower potentiometer or other voltage (or current) varying device is provided whose wiper or voltage varying member is driven by the yspeed control motor. The upper and lower limi-ts of the feeding rate of the auxiliary feeding means are independently adjustable by means including respective manually adjustable pctentiometers or similar voltage (or current) varying device-s. A first electrical circuit is provided which is responsive to the variable voltage (or current) outputs of the follower potentiometer and the manually adjustable, low limit setting potentiometer for deenergizing the input to the speed control motor which controls the rotation thereof in the direction which moves the aforesaid control member in a direction which progressively decreases the feeding rate of the auxiliary feeding means when lthe wiper of the follower potentiometer reaches or passes a position corresponding to the position of the wiper of the manually adjustable, low limit setting potentiometer. A second electrical circuit is provided which is responsive to the variable voltage outputs rate of the auxiliary feeding means are remotely controlled to accommodate dierent feeding rates of the machine.

In the case where the flexible material is supplied to the feeding apparatus in roll form, it is most advantageously supported on a platform or other support for rotation about a vertical axis which is coextensive with the axis of the roll. However, the broader 4aspects of the invention contemplate the use of rolls oriented 'with their axes horizontal. Feeding means drives the platform or other support in a direction to unwind the flexible material from the roll. In the case where the flexible material is semirigid, as in the case of steel wire, it is particularly advantageous to provide means for `automatically stopping the roll support platform when the wire or similar material unwinds at an excessive speed, as for example, where a coil of wire slips off of the roll. To this end, means are provided, preferably in the form of a ring of conductive material, yforming a contact member which surrounds the portion of lthe wire leaving the roll. When the wire contacts the ring, an electrical circuit is completed which effects the stopping of the `friction feeding means and the roll support platform. An excessive unwinding rate caused lby coil slippage or any other reason will throw the wire against the contact ring.

Other objects, advantages and features of the invention will 4become apparent upon making reference to the specification, the claims and the drawings wherein:

FIG. l is a diagrammatic View of a form of the invention applied to the feeding of wire from a roll;

FIG. 2 is Kan elevational view of a preferred embodiment of the invention shown in FIG. l applied toV a coil kspring producing machine;

FiG. 3 is a plan View of the apparatus shown in FIG. 2;

FIG. 4 is an enlarged perspective View of the assembly of contact members which controls the feeding rate of the roll support platform forming part of the apparatus 1 along section line 8 8 therein;

FIG. 9 .is an enlarged elevational view of the wire roll support platform and the means for driving the same;

FIG. l is a plan view of the wire roll support platform shown in FIG. 9;

FIG. ll is an enlarged fragmentary view of the top portion of the wire roll support platform shown in FIGS. 9 and l0;

FIG. l2 is an enlarged perspective view of the variable speed driving means for the wire roll support platform;

4 FIG. 13 is a fragmentary elevational View, partly broken away, of the Variable speed driving means of FIG. l2;

FIG. 14 is a horizontal sectional view through the variable speed driving rneans in FIG. 13, taken along section line 14-14 therein; and

FIG. l5 is a circuit diagram of the electrical control circuits which control the motors of the apparatus shown in FIGS. 2-14. i

General Description Referring now to FIG. l which illustrates diagrammatioally one application of the invention, where .steel wire 2 wound in a -toroidal-shaped roll 4 is fed to a pair of separable friction .

feed rollers

5 and 6 both continuously driven by a constant Xspeed drive motor 7 coupled thereto through gearing and the like (not shown), the upper pressure roller 6 is, in any' suitable manner, supported for movement toward and away from'the pressure roller 5 by roller lifter mechanism -generally indicated by reference numeral The roller lifter mechanism Sis constructed to lower intermittently the roller 6 upon the roller 5 for a predetermined (but variable) interval, so that a given amount of wire i-s fed to suitalble Wire cutting and forming `means used lto fabricate the particular wire article involved.V The means which interconnect the drive motor and the pressure rollers and the lifter mechanism 8 are old and well-known and form no part of the present invention. Such apparatus is disclosed, for example, in U.S. Patent No. 2,836,208, granted May 27, 1958. As previously indicated, an object of the invention is to feed the wire 2 between the

rollers

5 and 6 in a relatively slack condition, so that little or no slippage occurs between the

rollers

5 and 6 and the wire 2 (or other flexible material involved).

The roll of wire 4 is most advantageously supported upon a rota-table platform 1t) with the axis of rotation of the platform 10 coextensive with the axis of the roll 4. The platform 1t? carries a roll centering means 12 which tion of the platform 10. The platform 10 may be carried Y upon a rotatably supported shaft memberl which is driven 'by what has been generally referred to as an auxiliary feeding means generally indicated by reference numeral `17, which feeding means drives the platform 10 thro-ugh the member 16 at a speed which maintains a given degree or range of slack in the Wire 2.

In itsmost preferred form, the auxiliary feeding means includes a speed -control member 1S which may be associated with a variable speed drive i9 driven by a constant speed motor 2G. The position of the speed control `member 18 determines the speed at which the platform it) is driven and, as will appear, -the position thereof isV controlled by the degree of slack or tenseness of an unsupported portion of -the wire 2 suspended between two horizontally spaced points a and b.

The means for controlling the position of the speed control member 18 may comprise vertically spaced control means 22 and 24 respectively positioned above and below the suspended portion of the wire 2 when the wire has the desired amount of slack therein. In the most preferred `for-m of the invention, control means 22 and n 24 are electrical contact members, and the wire is grounded through the platform liti on which the roll 4 ofwire rests.

tween the

pressure rollers

5 and 6 and the wire 2 passing therebetween.

It can be seen that the elevation of the suspendedV portion of the wire 2 is a function of the degree-of slack pl D The upper contact member 22 is connected by a conductor 26 to a motor control means 30 which may include a iirst electrical circuit which, when grounded through contact member 22, effects the euergization of a first input 32 of a reversible speed control motor 36 which rotates the shaft 36' -thereof in one direction. The shaft 36 is coupled through suitable coupling means 37 to drive the con-trol member 18 in a direction which will progressively increase the speed of rotation of the platform when the speed control motor 36 is driven in said one direction. As long as the suspended portion of the wire 2 touches the upper contact member 22, the latter is grounded so as to effect the energization of the input 32 to the speed control motor 36. Any increase in speed of the platform 10 will unwind the wire from the roll 4 `at a faster speed which will reduce the tension in the suspended portion of the wire and, therefore, drop the wire.

The bottom contact member 24 is connected by a conductor 33 to the motor control means 30 which may include a second electrical circuit which, when grounded through the contact member 24, effects the energization of a second input 34 to the speed control motor 36 which will rotate the motor 36 in the opposite direction to drive the speed control motor 18 in a direction which will progressively decrease the speed of rotation of the platform 10 to reduce the degree of slack in the wire 2.

The drive motor which drives the Variable speed drive 19 may be controlled from a control panel 42 having a start push button 44 and a stop push button 46. The push 4buttons 44 and 46 have contacts electrically connected to the motor control means 30' which may include relays or the like which, in turn, control the energization of the motor 20.

The drive motor 7 which drives the

pressure feed rollers

5 and 6 may be controlled from the

push buttons

44 and 46, but, as illustrated, is most advantageously controlled from separate start and stop

push buttons

44 and 46 connected to a motor control circuit 47.

In accordance with another aspect of the present invention, means are provided for independently varying the upper and lower limits of the speed of operation of the variable speed drive means 19 as determined by the position of the speed control member 18. This means may include manually adjustable potentiometers of similar voltage (or current) varying means 48 and 50, sometimes referred to as low limit and high limit setting potentiometers, respectively, Whose wipers or movable control members are manually adjustable from knobs on the control panel 4Z. A follower potentiometer or similar voltage (or current) varying means 52. driven by the speed control motor 36 is also provided, wherein the position of the wiper or movable control member corresponds or is a direct function of the position of the speed control member 18. The voltage outputs of the

potentiometers

48, 50 and 52 are coupled to the motor control means 30 which may include a third electrical circuit responsive to the variable voltage outputs of the follower potentiometer 52 and the manually adjustable low limit setting potentiometer 48, which circuit de-energizes or prevents the energization of the low speed input 34 of the speed control motor 36 when the wiper of the follower potentiometer 52 reaches or passes a position corresponding to the manually adjusted position of Vthe wiper of potentiometer 48. The motor control means 30 yalso includes a fourth circuit responsive to the outputs of the follower potentiometer 52 and the -manually adjustable high limit setting potentiometer 58, which circuit de-energizes or prevents the energization of the high speed input 32 of the speed control motor 36 when the wiper of the follower potentiometer reaches or passes a position corresponding to the manually adjusted position of the wiper of the high speed setting potentiometer 50. Thus, by varying the knobs controlling the wipers of the

potentiometers

48 and 50, the upper and lower limits of the speed of the variable drive means 19, as controlled by the position of the speed control member 18, can be independently remotely adjusted.

In order to prevent a `fouling of the wire 2 due to an excessive unwinding speed of the Wire from the roll 4 caused, for example, by the slippage of a coil of wire from the roll 4, shutdown control means are provided preferably in the form of a rectangular ring of metal 53 through which passes the suspended portion of the wire 2 vadjacent the roll 4. The spacing of the vertically spaced horizontal 53a and 53h of the ring 53 is such that the wire 2 will not make contact therewith when the wire is raised or lowered to elevations which just bring it into engagement with the upper and

lower contact members

22 and 24. This condition is obtained since the portion of the wire 2 adjacent the roll 4 will vary in elevation to a smaller extent than will a portion thereof near the center of the suspended portion of the wire. The wire 2 will contact a side of the ring 53 only when the unwindin-g rate of the Wire is so abnormally high that centrifugal force or slippage of Ia coil of wire from the roll 4 will throw the wire against the ring 53.

The control ring 153 is connected by a conductor 54 to the motor control means 30 where it is associated with a fifth `electrical circuit which, when -grounded through the ring 53 by the contact of the latter with the wire 2, is engaged to operate a relay or yother control means which will de-energize the drive motor 20 to stop the rotation of the wire support platform 16. The relay or control means also effects the de-energization ofk the drive motor 7 for the

pressure feed rollers

5 and 6. To this end, a conductor 55 is shown extending to the motor control circuit 47.

Since the roll of wire 4 may be quite heavy, the inertia thereof may make it diticult to stop the platform 10 as soon as the drive motor 20 is de-energized, and, accordingly, this invention includes means for stopping the platform under these conditions. While various means may be utilized for this purpose, the platform 16 may, .for purposes of illustration herein, be provided with an upstanding peripheral wall 56 against Which la brake shoe 57 rides which is effective to stop the platform 14N Whenever the drive motor 20 is de-energized.

In the case where the pressure rollers 5 and 6 'provide an intermittent feed of the Wire, it should be apparent that, upon sep-aration of the

rollers

5 and 6, the wire 2 must not advance longitudinally of the lower roller 5 while the wire roll 4 continues to be rotated. Prevention of this longitudinal movement of the roll 4 may be inherently prevented by virtue of the construction of the wire cutting and forming means to which the Wire is fed, or it may be provided by various other means which will hold the wire in position on the roller 5.

Exemplary Embodz'ment of the Invention Shown in FIGS. 2-14 In FIGS. 2 and 3 there is shown a coil-spring producing machine 57 disclosed in U.S. Patent No. 2,836,- 205 to which is added or which incorporates the wire feeding apparatus of the present invention. The coilspring producing machine includes the aforesaid

pressure feed rollers

5 and 6 and also a second set of pressure feed rollers 5 and 6' which operate respectively in the same manner as

pressure rollers

5 and 6. The machine 57 may include at the wire-receiving end thereof a wire supplying mechanism 58 which removes kinks in the wire. The wire supplying mechanism comprises a circumferentially spaced series of rollers 59 between which the wire is looped once. The wire leaving the wire supplying mechanism 58 passes through a wire straightener 60 and between the rollers 5-6 and 5-6'. A coiling mechanism generally designated at 62 receives the wire discharged from the pressure rollers 5-6', and a transfer mechanism generally designated at 64 and comprising a plurality of coil-spring carrying arms 65 carries the coil springs from the coiling mechanism 62 to wire knotting and crimping mechanism generally designated at 66 for knotting and crimping one end of the coil spring. After the knotting and crimping mechanism 66 has performed its function, the transfer mechanism 64 carries the coil springs to a second knotting and crimping mechanism generally designated at 68 which knots and crimps the other end of the coil spring. The transfer mechanism then carries the completed coils of the coil spring to a stacking mechanism generally designated at 71B. The Various moving parts of the coil-spring producing machine, including the pressure rollers S--6 and 5 6', the transfer mechanism 64 and the knotting and crimping mechanisms 66 and 6s are all operated in timed relation throughvarious gears, cams and the like which may be operated from the aforesaid drive motor 7.

In the most preferred form of the invention, the upper and

lower contact members

22 and 24 previously described (FIG. l) are constructed and arranged together in an integral assembly illustrated in FIGS. 4-5. The upper contact member 22 is shown as an inverted U-shaped vmember which is supported in confronting relation to the legs of a U-shaped bottom contact member 24. The upper and lower contact members are held in spaced insulated relationship by a strip of insulating material 74 extending along the outside of each confronting pair of legs thereof. Nut and bolt assemblies 76 secure the insulating strips 74 to the ylegs of the contact members.

Extending along the outside of each insulating strip is a metal strip 7S having holes 8) receiving the projecting outer ends of the nut and bolt assemblies 76, the projecting ends thereof being spaced from the defining walls of the holes Sil, so that the contact members are insulated from the associated metal strips 78. Each metal strip 73 is fixed to the associated insulating strip 74 by nut and bolt assemblies 82, the heads of the bolts thereof being recessed within'counterbores 83 formed in the outer face of the insulating strip 74, so that the bolt heads do not touch the legs of the

contact members

22 and 24. The conductor 26 extending from the upper contact member 22 may be secured to one of the legs of the upper contact member by means including a terminal eyelet 26 secured to the end of the conductor 26 and a screw S4 passing through the terminal eyelet 26 and threading into the latter leg of the contact member 22. The conductor 26 is encased by insulating material 86 which, in turn, is surrounded by a cable sheath SS.

The conductor 33 associated with the bottom contact member 24 may be secured thereto'by means including a terminal eyelet 33' secured to the end of the'conductor k33 by a screw 99 passing through the terminal eyelet and threading into a leg of the lower contact member 2d. The conductor 33 is surrounded by insulating material 92 which, in turn, is surrounded by the aforesaid cable sheath 88 containing the other insulated conductor 26.

The assembly of the upper and lower contact members is supported for horizontal adjustment by means including a threaded rod 94 welded or otherwise secured to one of the metal strips 78 and threading into a horizontal tapped hole 96 in a clamping block 98., The threaded `rod 94 may be locked in any of its adjusted positions by a locking nut 99 threading therearound and bearing against a face of the clamping block 93. The clamping block 98 has a vertical hole 100 slidably receiving a vertical support post 102 anchored to a base 1&3 bolted or otherwise secured to the floor or a raised platform 164. rl`he block 9S is split between the hole 1619 and the face thereof opposite the one containing the hole 96. The block 98 is clamped in any one of its adjusted vpositions on the post 102 by a screw 105 which draws the split ends of the block 98 together.

The shutdown control ring 53 may be supported for vertical adjustment in a vertical guide 10S (FIGS. 7-8) by means including a vertical slide member 116 welded or otherwise secured to control ring 53 and slidable in the guide 1118 and lockable in any one of a number of Azontal leg 174 of a support Ybracket 176. lThe bracket.

motor 2d is deenergized.

vertical positions by screws 111 passing through vertical slots 112 in the member 110 and threading into holes The rotatable platform 1d, the drive motor 20, the

variable speed drive 19 and the speed controi motor 36 preferably are arranged in an integral assembly (FIGS. 9-10) supported upon a base plate 126 suitably anchored to the door or platform 104. The variable speed drive 19 and the drive motor 2f) are arranged together in coaxial relation upon the base plate and the speed control motor 36 is supported in a housing 122 fixed to the top of the variable speed drive 19. The construcp tional details of the variable speed drive 19 and its relationship to the speed control motor 36 will be described hereinafter.

Extending up from the base plate 12d adjacent the variable speed drive 19 is a boss 124 which has a vertical bore 126 supporting an upstanding stationary post 128. Mounted in any suitable way upon the top of the bossV 124 is a thrust bearing assembly 131i which surrounds the `post 128. The thrust bearing assembly 130 rotatably supports a gear 132 which is driven by the variable speed drive 19 in a manner to be explained. The gear 132 has an upwardly extending sleeve portion 134 surrounding the post 12S and upon which is secured a flange 136 by screws 13%. The flange 136 is connected to the bottom of a sleeve 141i surrounding the post 128 and having an upper flange 142. The platform 10 is supported for rotation upon the flange 142 by means including a series of depending bosses 144 welded or otherwise secured to the bottom of the platform 10 and a series of screws 146 passing through the flange 142 and threading into tapped holes in the bosses 144.

The wire roll centering means 12 in the center of the Y Vplatform 10 may comprise an open-ended metal cylinder 148 concentrically related with yrespect to the axisV of the post 123 and positioned on top of the platform 10. The cylinder fixedly carries on the top thereofa cap member 158 which, by means of bolts 160 or other suitable means, carries a bearing assembly 162 which engages with and rotatably supports the cylinder 148 about the top of the post 128.

Extending radially outwardly from the cap member 158 are a series of circumferentially spaced rods 164 which are welded or otherwise secured to the cap member 158. A downwardly and outwardly extending arm 166 is fixed to the end of each rod 164. Each arm 166`has ^a split upper end 168 and a lateral hole joining the Asplit .end and receiving the `end of the rod 164. Thesplit end of the arm 166 is clamped on the rod 164 by a screw 171i'. The toroidal-shaped wire roll 4 rests on the platform 10 and the inner margin thereof engages the arms 166 which hold the roll '4- in a position Where its axis is coextensive with the axis of rotation of the platform 10.

As previously indicated, the platform wis providedV with an upstanding peripheral wall 56 along the outside of which rides a brake shoe 57 which applies suicient braking forces to stop Vthe platform 1t) when the drive In the embodiment orf the invention being described, the brake shoe 57 is pivotally supported upon the upper offsetend of a vertical arm 172 ivotally supported intermediate its ends ion the hori- 176 has a vertical leg 177 secured to the Abase plate V120. Threaded through a horizontal tapped bore 178 in the bottom end of the verticalY arm 172 is an adjusting screw 181i. The adjusting screw 130 has a flange 19t) spaced from the inner end thereof which provides a shoulder against which bears one end of a coil spring 192. The other end of the coil spring 192 bears against a shoulder 194 provided on the vertical leg 177 of the bracket 176. The ends of the coil spring 192

surround extensions

191 and 197 located respectively on the end of the screw 180 and on the bracket leg 177. The coil spring 192 urges the bottom end `of the vertical arm 172 outwardly and, in so doing, urges the brake shoe 57 -against the peripheral platform wall 56. By adjusting the degree to which the adjusting screw 180 is threaded into the tapped hole 17S at the bottom of the vertical arm 172, the braking pressure between the brake shoe 57 and the peripheral platform Wall 56 is varied.

Referring now to FIGS. 'l2-14, the construction of the variable speed drive 19 and its connection with the reversible speed control motor 36 and the gear 132 which drives the platform 10 are shown therein. The variable speed drive 19 is one currently being manufactured by Graham Transmissions, Inc., or Menominee Falls, Wisconsin and comprises a rotatably supported carried 2% which is coupled to the `drive shaft of the constant speed motor 2G. A series of tapered rollers 261 are supported for independent rotation upon the carrier 2Go and the axes of the rollers incline at an angle equal to their taper, so that their 'outer edges are maintained parallel 'to the axis of rotation of the carrier 200. The aforesaid speed control member 13 is, in the embodiment of the variable speed drive illustrated, a ring supported for axial sliding movement upon a pair lof stationary rods 294. The control ring 18 carries slide members 266 which slide upon the rods 204. The outer ends of the tapered rollers 201 carry pinion gears 298 which mesh with an internal ring gear 210. The inside surface of the control ring 18 engages the outer edges of the tapered rollers 2M, and the path of rotation of the internal ring gear 210 is a function of the axial position of the control ring 18 with respect to the tapered rollers. It can be shown that maximum speed is obtained when the control ring 18 is in its far right hand position where it engages the wide end of the tapered rollers. The speed of rotation of the internal ring gea-r 210 will progressively decrease as the control ring 1S is moved progressively to the left of the latter position.

The axial position of the control ring 18 is varied by means including a control segment 212 which is pivotally supported upon the lframe of the variable speed drive 19 for movement about a verticalyaxis. A suitable connection is made between the control segment 212 and thev control ring 1S, so that pivoting of the control segment will move the control ring axially to a position depending upon the angular position of the control segment.

The control segment has gear teeth on the perimeter thereof which mesh wtih a pinion 2114 carried on the bottom end of a shaft v216 driven by the reversible speed control motor 3-6 mounted within the housing 122. As the shaft 216 is driven in one direction or the other, the segment 2.12 will be rotated in one direction or the other to move the control ring 18 to the right or to the left. The shaft 216 also carries a pinion gear 218` which meshes with a gear 220 driving the wiper of the aforesaid follower potentiometer 52 which is mounted within the housing 122 through a gear 221.

The ring gear 210 drives a worm wheel 222 which meshes with a gear 224 carried at the bottom end of a shaft 226. The shaft 225 carries on the top thereof a gear 227 which meshes with the aforesaid gear 132 which drives the platform 10.

Motor Control Circuits (FIG.

In FIG. l5 there is shown a circuit diagram of the various circuits which control the operation of the aforesaid drive motor 7, drive motor 2o and speed control motor 36. This circuit diagram includes what is repre` sented as motor control means 3? and motor control circuit 47 in FIG. 1. The circuits there shown may be operated from a 220 volt alternating current'supply fed to the primary 230 of a transformer 232. The transformer 232 has a secondary winding 2134 which provides, for example, 6 volts across a pair orf power conductors 236-4237, the power conductor 236`be`ing shown as a grounded conductor. The start and stop push button switches 44 and `i6 for the drive motor 7 as aboveindicated are associated with the circuit 47 containing relays and contacts thereof to be described. EIn the description to follow, the relay contacts are shown in their positions when the associated relay coils are de-energized. Also, the contacts for a particular relay are identiiied by reference characters corresponding to that used to identify the coil of that relay with a number added to identify the set of contacts involved.

The circuit 47 comprises a start relay R1 connected to the power conductor 2137, normally-open push button switch 44' connected in parallel with normally-closed push button switch 46 and normally-open holding contacts R1-1 in series therewith, and normally-closed contacts R2-1 of -a shutdown control relay R2 connected to the other power conductor 236. Momentary depression of start push button switch 44 will energize start relay R1' which will be locked in upon closure of the holding contacts -R1-1. Relay R1 has a series of normally-open contacts R1'-1, R1-2 and R1-3 controlling the power input to the drive motor 7. The drive motor 7 is shown as a 3-phase electric motor having three input lines respectively leading to a S-phase voltage supply through the normally-open contacts R11, R1'-2 and R13. Momentary :depression of the stop push button switch 416 will break the holding branch including holding contacts Rill so as to de-energize the start relay R1 which de-energizes the drive motor 7.

A second circuit 213-8 is provided for controlling the energization of the drive motor 20 and includes a start relay R1 connected to the power conductor 2317, a parallel circuit including normally-open push button switch 44 in one branch and normally-open holding contacts Rel and normally-closed stop push button switch 46 in the other branch, and normally-closed contacts R2-2 of shutdovm control relay R2 connected to the other power conductor 236. Start relay R1 has normally-open contacts R14, R1-2 and R1-3 in the respective inputs of the drive motor 20 which is a 3-phase motor. Momentary depression of start push-button switch 44 will energize start relay R-l to close holding contacts R1-1 and thus lock in the energization of start relay R1 to effect energization of the drive motor 2t); Momentary depression of stop push butt-on switch 46 will break the holding branch to start relay R1 to de-energize the same and effect opening of the contacts R1-1, R1-2- and R14,` to de-energize the drive motor 20.

A third circuit 239 is provided including the shutdown control ring 53 connected through conductor 54 to the shutdown control relay R2 connected to the power conductor 237. Whenever the wire 2 touches the ring 53, the l-atter is grounded .through conductor 236 to energize shutdown control relay R2. Energization of shutdown control relay R2 opens the aforesaid contacts R2-1 and R2-2 in motor control circuits 47 `and 238 to break the holding branches of start relays R1 and R1 to thereby de-energize the

drive motors

7 and 20.

The speed control motor 36 is `shown operated from a Z-phase voltage source obtained from a secondary winding 242 Iof the transformer 232 which secondary winding has a pair of

power conductors

244 and 246 connected thereto. The speed control motor 36 is a reversible type motor which has a iirst input 24S which, when energized, will rotate the shaft of the speed control motor in a direction which will drive the control ring 1-8 to the right so as to progressively increase Ithe speed of rotation of the wire roll 4. The motor 36 has a second input 25) which, when energized, operates the shaft of the speed control motor in the opposite direction which drives the control ring 18 to the left so as to decrease progressively `the speed of rotation of the wire roll 4. The input 248 is connected to the power conductor 244 through normally-open contacts R53-1 of a high speed limiting control relay R and normallyopen contacts R4-1 of a speed-up control relay 'R4 associated with the upper contact member 22. The input 250 is connected to the power conductor 244 through a set of normally-open contacts R6-1 of ya low speed limiting control relay R6 and a set of vnormally-open contacts R3-1 of a slow-down control relay R3 associated with the lower Contact member 24.

The speed-up control relay R4 is connected between the power conductor 237 and the conductor 26 leading to the upper contact member 22. When the wire 2 touches the upper contact member 22, the latter contact member will be connected to the grounded power conductor 236 to energize speed-up control relay R4 resulting in the closure of contacts Rit-1 associated with the input 24S to the speed control motor 36. This energizes the speed control motor to drive the shaft thereof in one direction provided the contacts lRS-l are closed. As will be explained, these contacts are closed so long as the adjusted upper speed limit of the variable speed drive 19 has not been reached.

The slow-down control relay R3 is connected between power conductor 23.7 and the conductor 33 leading to the bottom contact member 24. When the wire 2 touches the latter contact member, slow-down control relay R3 is energized which closes contacts 1R34 associated with the input 25@ `of the speed control motor 36 to energize the latter to drive the shaft thereof in the opposite direction, provided contacts R-l are closed. As will appear, the latter contacts are closed as long as the adjusted lower speed limit of the variable speed drive means 19 has not been reached.

The provision of the speed limiting control contacts 11S-1 and 'R6-1 provides for automatic shutdown of the speed control motor 36 whe-never the drive motors 7 and/ or 20 are dre-energized. In such case, the suspended portion of the wire will be in one of three positions, in contact with upper contact member 22, between the

contact members

22 and 24 or -in contact with lower contact member 24. Ot course, if the wire is not touching either

contact member

22 or 24, relays R3 and R4 will be de-energized and their contact-s R3-1 and ARf-1 associated with

inputs

248 and 250 will be open to deenergize the motor 36. If the wire is contacting either the upper or

lower Contact members

22 or 24, as will appear, the speed control motor will be continuously energized so as to drive the Wiper of follower potentiometer 52 to a position where high or low speed limiting relays R5 or R6 will operate to open the contacts R5-1 or Rc-l associated with the energized motor input in- A volved.

The aforesaid high and low speed limiting control relays R5 and R6 are associated with a potentiometer circuit generally indicated by reference numeral 252 with which the aforesaid follower potentiometer 52 and the low and high limit setting potentiometers 48 and `5i) are associated. The circuit 252 includes a pair of

power input transformers

254 and 256 whose

primary windings

258 and 26? are connected to the secondary winding 242 of transformer 232. Transformer 254 Vhas a secondary Winding 262 which is connected to the input of a conventional full wave diode rectier circuit 264. The transformer 256 has a Asecondary winding 266 which is connected to a conventional full wave diode rectifier circuit 268. The outputs of lthe rectiiier circuits 264 and 'of the low and high

limit setting potentiometers

48 and 50 and the follower potentiometer 52. The positive ter- Y 12 minal of the tilter 270 is connected to the bottom ierminals of the potentiometers 48, v50 and 52. The wiper or movable Contact of the high limit setting potentiometer 50, indicated by reference numeral 50', is associated with a transistor circuit generally indicated by reference numeral 276. The wiper or movable contact ofthe low limit setting potentiometer 4S, indicated by reference numeral 48', is associated with a transistor circuit generally indicated by reference numeral 273. The wiper or movable contact of the follower potentiometer 52, indicated by reference numeral 52', is associated with both transistor circuits 276 and 278.

Transistor circuit 276 includes a pair of PNP

type junction transistors

286 and 282. The transistor 280 has an emitter electrode 284 connected to the positive terminal of the iilter 272, a collector electrode 286 connected through a resistor 288 to the negative terminal of the iilter 272, and a base electrode 290 connected to the wiper 50 of the high limit setting potentiometer 5t) by a conductor `2911. The other transistor 282 has an emitter electrode 296 connected to the positive terminal of the -iilter 272, a collector electrode 292 connected through the aforesaid high speed limiting control relay RS to the negative terminal of the 1iilter `272, and a base electrode 294 connectedV to the junction between resistor 288 and the collector electrode 286 of the transistor 280. The wiper 52 of .the follower potentiometer is connected by a conductor 295 to the negative lterminal of the filter 272. l

As is well known, with the connection of the 'PNP type transistor 282 described, it will be a non-conductive state which will dez-energize high speed limiting control relay R'S when the base electrode 294 thereof is positive with respect to the emitter electrode 290. Conversely, the transistor 232 will be in a conductive state to energize the relay R5 when the base electrode V294 Vis negative with respect to the emitter electrode 290. Accordingly, transistor 282 will be in a conductive state to energize relay R5 when transistor 280 is in a nonconductive state, since, then, the base electrode 294 will be connected to the negative terminal of the ilter 272 through the resistor 282. Conversely, transistor 282 will be in a non-conductive state when ltransistor 280` ispconductive. Since transistor` 28o is the same kind of Aa transistor as transistor 282, the former will be in a nonconductive state to effect .the energization of relay R5 as long as the wiper 52' of the follower potentiometer V52 is in a position above that corresponding to the position of the wiper 5%' of the high limit setting potentiometer 50, wherein the wiper 50 connected to Vbase electrode 299 is `positive with respect to the emitter electrode 284 which is always at the potential of the wiper 52 o-f the follower potentiometer `52. As previously indicated, when relay R5 is energized, its normally-open contacts R5-1 associated with the speed-up input 248 of the speed control motor 36 will be closed to effect speed-up of the variable speed drive 19 as long as the wire 2 is contacting conductor 22. When, however, the follower potentiometer wiper 52' reaches or just moves beyond the corresponding posi-tion of the wiper 50' of high limit setting potentiometer 50, the potential of base electrode 293 of transistor 28S will be negative lwith respect to the emitter electrode 284 which will render the transistor 280 conductive. This, as above indicated, will render transistor 282 non-conductive and de-energize lthe relay R5 to open contacts RS-l which disables or de-energizes the speed-up input 248 to the speed Vcontrol motor 36.

The transistor circuit 27S associated with the low limit setting Ypotentiometer 48 includes one PNPl type junction transistor 298 and one NPN junction type transistor 300. The transistor 298 has an emitter electrode 302 `connected to the positive terminal of the lter 272, a collector electrode 304 connected through a resistor 306 to the negative terminal of the tilter 272, and a base elec- '13 trode 308 connected to the wiper `i8 of the low limit setting potentiometer 43 by a conductor 369'.

The transistor 309 has a collector electrode 308 connected to the positive terminal of the fil-ter 272, an emitter electrode 310 connected through the low speed limiting relay R6 to the negative terminal of the filter 272, and a base electrode 312 connected to the junction between resistor 366 and the collector electrode 3M of transistor 298. The NPN type transistor 31Miis conductive to energize relay R6 which closes contacts Rd-l in the slow-down input 250 of speed control motor 36 when the base electrode 312 is positive with respect to the emitter 310. This occurs when the transistor 298 is in a conductive state. Conversely, transistor 300 is in a non-conductive state when its base electrode 312 has the potential of the negative terminal of the filter 272 effected by the non-conductive state of transistor 298. Transistor 298 is conductive as long as the Wiper 52' of follower potentiometer 52 is below a position corresponding to the` position of the wiper 4S of the low limit setting potentiometer 48. Whenever the Wiper 52 of the follower pctentiometer reaches or goes slightly beyond the corresponding position of wiper 48', the transistor 29S will become conductive which will render the transistor 309 nonconductive and de-energize relay R6. This opens contacts R6-'1 associated with the slow-down input 25@ to speed control motor 36 to deenergize the same.

I-t should be understood that numerous modifications may be made in the exemplary and preferred forms of the invention just described Without deviating from the broader aspects of the invention.

What l claim as new and desire to protect by Letters Patent of the United States is:

1. Apparatus for feeding flexible material comprising: first feeding means for engaging the longitudinal surface of said flexible material and imparting intermittent for- Ward longitudinal movement thereto, second feeding means for advancing said flexible material to `said first feeding means in a slack condition, means responsive to the degree of slack in said flexible material being fed to said feeding means for progressively adjusting the feeding rate of said second feeding means to maintain the flexible material in a lslack condition, first feed rate limit control means for adjusting the upper limit of the speed of operation of said -second feeding means, and second feed rate limit control means for adjusting the lower limit of the speed of operation of said second feeding means independently of the adjusted upper limit thereof.

2. Apparatus for feeding a predetermined length of flexible wire material from a wound roll thereof having a diameter many times the thickness of the roll, said apparatus comprising: first feeding means for engaging the longitudinal surface of an unwound section of said flexible material and imparting forward longitudinal movement thereto, roll support means for rotatably supporting -said roll of flexible material for rotation about a generally vertical axis, driving means for driving said support means to advance said `flexible material to said first feeding means in a slack condition, `the flexible material having at least one portion between said roll support means and said first feeding means which is suspended between two horizontally spaced points, means responsive to ythe raising of said suspended portion above a predetermined elevation by the tensing of said flexible material for controlling said driving means to provide increased f slack in said flexible material, and means responsive to the dropping of said suspended portion of said flexible material below a given elevation for controlling said driving means lto prevent the complete collapse of said suspended portion of said flexible material.

3. Apparatus for feeding flexible material comprising: first feeding means for engaging the longitudinal surface of said flexible material and imparting intermitted forward longitudinal movement thereto, second feeding means for advancing said flexible material to said first feeding means in a slack condition, the flexible material having at least one portion between said first and second feeding means which is suspended between two horizontally spaced points, means responsive to the raising of said suspended portion above a predetermined elevation by the tensing of said flexible material by progressively increasing the feeding rate of said second feeding means to provide additional slack in said flexible material, means responsive 'to the dropping of said suspended portion of said flexible material below a given elevation by progressively decreasing the feeding rate of said second feeding means, and limit control means for independently varying the upper and lower limits of the feeding rate of said second feeding means.

4. Apparatus for feeding flexible conductive material from a roll thereof, said apparatus comprising: first feeding means for engaging the longitudinal surface of an unwound section of said flexible conductive material and imparting intermittent forward longitudinal movement thereto, support means for rotatably supporting said roll of flexible conductive material, driving means for driving said `support means to advance said flexible conductive material to' said first feeding means in a slack condition, the flexible conductive material having a portion suspended between said roll and Ia point spaced horizontally thereof, and speed control means responsive to the degree of slack in said suspended portion of said flexible conductive material for controlling the speed of operation of said driving means to maintain a given degree of slack in said flexible conductive material, said control means comprising insulated upper and lower Contact members located respectively above and belovt said suspended portion of said flexible conductive material which touches said upper contact member when it is raised thereagainst by increased tension in the `flexible conductive material and which touches said lower contact member when lowered thereagainst by decreased tension in the flexible conductive material, first electrical circuit means in which said flexible conductive material and upper contact me-mber are electrically connected for progressively speeding up said driving means as long as said flexible conductive material touches said upper contact member, and second electrical circuit meansin which said flexible conductive material and lower contact member are electrically connected for progressively slowing down said driving means as long as said flexible conductive material touches said lower contact member, said driving means remaining at the last adjusted speed thereof when the flexible conductive material is out of contact with said upper and lower contact members, and shutdown means for stopping said driving means when the latter feeds said flexible conductive material at an abnormal feeding rate in excess of the rate which initially brings said flexible conductive material into contact with said lower contact member, said shutdown means including a contact member substantially completely encircling and normally spaced from the portion of the flexible conductive material leaving said roll at a normal rate and being in the path of movement thereof when being fed at said abnormal feeding rate when the conductive material abnormally flies off said rollin a random direction and an electrical circuit in which said flexible conductive material and said last mentioned contact member are electrically connected for stopping said driving means when said flexible conductive material touches said last mentioned contact member.

5. Apparatus for feeding a predetermined length of metal wire from a wound roll thereof having a diameter many times the thickness of the roll, said apparatus comprising: first feeding means for engaging the longitudinal surface iof -an unwound section of said Wire and imparting forward longitudinal movement thereto, support means for rotatably supporting 4said roll of wire for rotation about a generally vertical axis, driving means for driving said support means to yadvance said aroasvo wire to said first feeding means in a slack condition, the wire having a portion between said support means land said first feeding means which is suspended between said roll `and a point spaced :horizontally thereof, and speed control means responsive to the `degree of slack in said suspended portion of said wire Ifor controlling the speed of operation of said driving means .to maintain a fixed degree of slack in said Wire, said control means comprising insulated upper and lower contact members located respectively above and below said suspended portion of said wire which touches said upper contact member when it is raised thereagainst by increased tension in the wire and which touches said lower contact member when it is lowered thereagainst by decreased tension in the wire, first electrical circuit means in which said wire and upper contact member are electrically connected for progressively speeding up said driving means as long as said wire touches said upper contact member, second electrical circuit means in which said wire and lower contact member are electrically con'- nected for progressively slowing down said driving means as long as said wire touches said lower contact member, said driving means remaining at the last adjusted speed thereof when the wire is out of contact with said upper and lower contact members, and shutdown means for stopping said driving means when a coil of wire slips ofi said roll and moves in any one of a number of directions, said shutdown means including a contact member substantially completely encircling and normally spaced from the portion of the wire leaving said roll, and an electrical circuit in which said wire and last mentioned contact member are electrically connected for stopping said driving means when the wire touches said last mentioned contact member.

6. Apparatus for feeding flexible material from a roll thereof said apparatus comprising: first feeding means for engaging the longitudinal surface of an unwound section of said flexible material and imparting intermittent forward longitudinal movement thereto, roll support means for rotatably supporting said roll of flexible material, variable speed drive for rotating said support means to advance said fiexible material to said first feeding means in a slack condition, said lieXible material extending between said first feeding means and said roll support means with at least one portion therebetween suspended between two horizontally spaced points, variable speed drive means including a speed control member which progressively increases the speed `of said drive means when 4moved progressively in one direction and which progressively 4decreases the speed of said drive means when moved progressively in the other direction, a reversible speed control motor for controlling the movement lof said speed control member and including a first input which, when energized, drives the speed control motor in one `direction to drive said speed control member in said one direction to increase the speed of said variable speed drive means, and -a second input which, when energized, drives the speed control motor in the opposite direction to drive said yspeed control member in the opposite direction to decrease the speed of said variable speed drive means, a tension sensing member above said Suspended portion of said flexible material, said tension sensing member being responsive to the raising 'of said suspended portion above =a first elevation by tension in the iiexible material by energizing said first input of said speed control `motor only as long as the suspended portion remains above said first elevation, an excessive slack sensing member below said suspended portion responsive to the dropping of the suspendedpoi'tion below a second elevation lower than said first elevation by energizing said second input of said speed control motor only as long as the suspended portion remains below said second elevation, and means for independently varying the upper and lower limits of the speed of said variable speed drive means comprising a follower 'control unit having a it? Y voltage varying member driven by said speed control motor so as to occupy a position representing the position of said speed control member, a high limit setting control unit having a manually adjustable voltagevarying member for setting an upper limit to the speed of said variable speed drive means, a low limit setting con-k trol unit having a manually adjustable voltage varying member for setting a lower limit to the speed of said variable speed driving means, a first electrical circuit responsive to the variable voltage outputs of said follower control unit and said high'limit setting control unit for cle-energizing the first input of said speed control motor when the voltage varying member of said follower control unit reaches a position corresponding to the position of the voltage varying member of said high limit setting control unit, and a second electrical circuit responsive to the variable voltage outputs of said follower control unit and said low limit setting control unit for de-eners gizing the second input of said speed control motor when the vol-tage varying member of said follower control unit reaches a position corresponding to the position 'of the voltage varying member of the low limit setting control unit. s

7. Variable speed drive means including'a speed control member which progressively increases the speed of said drive means when moved progressively in one direction and which progressively decreases the speed of said drive means when moved progressively in the other direction, a reversible speed control motor for controlling the movement of said'speed control member and including a first input which, when energized, drives the speed control motor in one direction to drive said speed control member in said one direction to increasethe speed of said variable speed drive means, and a second input which, when energized, drives the speed'control motor in the opposite direction to drive said speed 'control member in the opposite `direction to decrease the speed of `said variable Vspeed drive means, means for energizing said first input, means for energizing said second input, and means for independently varying the upper and lower limits of the speed of said variable speed drive means comprising a follower control unit having a voltage varying member driven by said speed cont-rol motor so as to occupy aposition representing the position of said speed control member, a high limit setting control unit having a manually `'adjustable voltage varying member for setting an upper limit to the speed of said variable speed drive means, a low limit setting controlunit having a manually adjustable voltage varying rnember for setting a lower limit to the speed of said variable speed driving means, a rst electrical circuit responsive tothe variable voltage outputs -of said follower control unit and said high limit setting control unit for de-energizing .the first input of said speed control motor when the voltage varying member ofrsaid follower control unit reaches a position corresponding to the position yof the voltage varying member of said high limit setting control unit, Aand a second electrical circuit responsive to the variable voltage outputs of said follower control unit and said low limit setting control runit for de-energizing the second input of said speed control motor when the voltage varying member of said follower control unit reaches a position corresponding to the position of the voltage varying member of thelow limit setting control unit.

8. Variable speed drive means including a speed control member which progressively increases the speed said drive means when moved progressively in one d1- rection and which progressively decreases the speed of said drive means when moved progressively in the other direction, a reversible speed control motor for controlling the movement of said speed control member, and means for independently varying the upper and lower limits of :the speed yof said variable speed driving means comprising a source of voltage having a pair of output terminals, a follower potentiometer comprising a resistance having a pair of outer -terminals and a movable contact driven by said reversible speed control motor for making progressive connection With different points along said resistance, a high limit setting potentiometer comprising a resistance having a pair of outer terminals and a manually adjustable movable contact for making progressive connection with different po'mts dong said latter resistance, a low limit setting potentiometer comprising a resistance having a pair of outer terminals and a manually adjustable movable contact for making progressive connection with different points along said last mentioned resistance, means 'connecting said outer terminals of said potentiometer resistances in parallel across said output terminals of said voltage source, a first voltage difference sensing circuit responsive to the difference in voltage at the movable contacts of said follower potentiometer and said high limit setting potentiometer ffor de-energizing said speed control motor to prevent said speed control member from exceedinU a high speed position thereof, a second voltage difference sensing circuit responsive to the difference in voltage at the movable contacts of said follower potentiometer and said low limit setting potentiometer for deenergizing said speed control motor to prevent said speed control member from exceeding a low speed position thereof.

9. Apparatus for feeding ilexible material in a slack condition, said apparatus comprising feeding means for feeding said flexible material at a `controlled rate from a roll of such material, slack responsive means responsive -to a degree of slack in said flexible material below a first amount of slack by increasing the feeding rate of said feeding means for increasing the slack in said flexible matern'al and responsive `to a degree of slack in said flexible malteiial above a second amount of slack in excess of said rst amount of slack by decreasing the speed of said feeding means for decreasing the slack in said flexible material, and shutdown control means including encircling means adjacent to said roll and substantially completely encircling and normally spaced from an unwound portion of said flexible material leaving said roll, and means responsive to the movement of said unwound portion of said flexible material contiguous to said encircling means for stopping said feeding means, the spacing between said flexible material and shutdown control means Ibeing such that said ilexible matenial moves into contiguous relation with the shutdown control means when an abnormal amount of said flexible material is fed from said roll in excess of that required to initially operate said slack responsive means.

10. Apparatus for feeding ilexible material in a slack condition, said apparatus comprising: feeding means yfor feeding said flexible material from -a roll of such material, slack responsive means responsive to the degree of slack of said flexible material -for controlling said feeding means to maintain a given degree of slack in said flexible material, and shutdown control means including encircling means adjacent to said roll and substantially completely encircling and normally spaced from an unwound portion of said flexible material leaving said rolls, and means responsive to the movement of said unwound portion of said flexible material contiguous to said encircling means for stopping said feeding means, the spacing between said flexible material and shutdown control means being such that the flexible material moves into contiguous relation with the shutdown control means when the degree of slack or tension in said wire is in excess of that to be controlled by said slack responsive means.

References Cited in the le of this patent UNITED STATES PATENTS 1,773,709 Daniels Aug. 19, 1930 1,828,506 Morse Oct. 20, 1931 2,208,340 Parsons July 16, 1940 2,270,064 Littell Jan. 13, `1942 2,603,428 Newco-mbe July 15, 1952 2,725,508 Bailey et al. Nov. 29, 1955 2,734,253 Suggs Feb. 14, 1956 2,771,984 Ranney Nov. 27, 1956 2,800,326 Berger July 23, 1957 2,828,455 Kraay et al Mar. 25, 1958 2,877,397 Poschner et al. Mar. 10, 1959

Claims

1. APPARATUS FOR FEEDING FLEXIBLE MATERIAL COMPRISING: FIRST FEEDING MEANS FOR ENGAGING THE LONGITUDINAL SURFACE OF SAID FLEXIBLE MATERIAL AND IMPARTING INTERMITTENT FORWARD LONGITUDINAL MOVEMENT THERETO, SECOND FEEDING MEANS FOR ADVANCING SAID FLEXIBLE MATERIAL TO SAID FIRST FEEDING MEANS IN A SLACK CONDITION, MEANS RESPONSIVE TO THE DEGREE OF SLACK IN SAID FLEXIBLE MATERIAL BEING FED TO SAID FEEDING MEANS FOR PROGRESSIVELY ADJUSTING THE FEEDING RATE OF SAID SECOND FEEDING MEANS TO MAINTAING THE FLEXIBLE MATERIAL IN A SLACK CONDITION, FIRST FEED RATE LIMIT CONTROL MEANS FOR ADJUSTING THE UPPER LIMIT OF THE SPEED