US2775414A - Constant tension control mechanism - Google Patents

Description

Dec. 25, 1956 D. B. RUSH ETAL CONSTANT TENSION CONTROL MECHANISM Filed July 9, 1953 IN VEN TORS. DAL: Hus, fl/JZLMM SEW/V6519, J'OXIVa THOMAS 6919/ flazvnzo .5. Waapx 5 AY'Y'O/F/VA'Y I: I I/ 4 V F 40 4---@ 4 nited Stat s Patent iice,

2,775,414 CONSTANT TENSION CONTROL MECHANISM Dale B. Rush and William E. Springer, Columbus, Ind, and John B. Thomas, Belmont, and Donald E. Woody, Medford, Mass., assignors, by mesne assignments, to

The Reliance Electric and Engineering Company, Cleveland, Ohio, a corporation of Ohio Application July 9, 1953, Serial No. 367,042 Claims. Cl. 242-75 The present invention relates to a drive for a storage roll for flexible material, and the primary object of the invention is to provide a mechanism which, in response to tendencies toward variation in a condition existing in a length of such material moving relative to the axis ofsaid roll, such as, for instance, tension, will automatically? vary the speed at which such a storage roll is driven, either for winding or for unwinding of the material, in

order to maintain such condition against substantial jects, our invention may be embodied in'the form illus trated in the accompanying drawings, attention being.

called to the fact, however, that'the drawings are illustrative only, and that change may be made in the specific construction illustrated and described, so long as the scope of the appended claims is not violated.

Fig. 1 is an end elevation of one form of the control of the present invention, assembled with a beam let-01f mechanism, fragmentarily and somewhat diagrammatically illustrated;

Fig. 2 is a side elevation thereof;

, Fig. 3 is an enlarged vertical section through a preferred form of combined variable speed and difierential mechanism which may be used in the practice of our invention; and

Fig. 4 is a section taken substantially on the line 4-4 of Fig. 3.

Referring more particularly to the drawings, it will be seen that we have shown a frame in which is journalled a shaft 11 upon which is carried a storage roll 12. A mass 13 of flexible material is shown wound upon the roll 12; and the parts are shown at a time, in the cycle of the suggested machine, very shortly after the initiation of an unwinding operation. It will be seen that the material is led from the mass 13 in a section 14 which is always tangent to the elfective surface of the mass 13 (sometimes referred to as the effective surface of the storage roll) and, after passing over a control element later to be described, extends in a run 16 to mechanism, suggested at 15, through which the material is forwarded at a constant lineal velocity to a point of use (not shown).

A trackway 17, which may comprise a pair of parallel, horizontal racks, as shown, is supported upon the frame 10 in a plane spaced from, but substantially parallel with, the axis of the roll 12, said trackway extending in a direction transverse to said axis. Wheels 18, which may be toothed cogs, as shown, for meshing engagement with the said racks, support an axle 19 upon said track- Patented Dec. 25, 1956 a way 17 for movement therealong; and a roller 20 is s'upported upon the axle 19 for free rotation about the axis thereof. The roller 20 constitutes the control element above referred to, sometimes called a bearing member.

5 As shown, the roller 20 may be the conventional whip iroll of a loom.

An arm 21 is mounted for oscillation about a fixed axis 22 which preferably coincides with the axis of the shaft 11. In the illustrated embodiment of the invention,

10 said arm is actually mounted upon a projection of said :ishaft; the arm being free, however,for'oscillation with respect to said shaft. The. arm 21 projects into'proximity with the trackway-17 and, at its outer end, is bifurcated to define a slot 23, elongated in the direction of length of the arm, and freely receiving aprojecting end 55.? of the axle 19. Thus, the 'roller is operatively connected to the arm 21, whereby movement of said roller along the trackway 17 willbe accompanied by oscillation of the arm 21 about its journal axis22. A cable 24' 20 has one end anchored to the-arm 21, passes over a pulley -35? 25, and supports a weight 26, whereby said arm is yield-, the left-hand-end of ably biased to hold the roller 20 at the trackway-17.

It will be seen that the roller 20 bears against the inner surface of the material 14 withinthat sector which is w: defined between the point of tangency of the section 14 with the effective surface of the roll, and a plane includin the axis of the roll 12 and normal to the run 16.

A shaft indicated at 27 is driven through suitable means 2;; warding means 15. A sprocket 28 on the shaft 27 is connected, through a chain 29, to drivea sprocket 30 on a shaft 31 of a control assembly indicated generally by the reference numeral 32, Said control assembly is illustrated in detail in Figs. 3 and 4..

7 Within a frame or housing 33 is journalled. a first shaft 31. ,A second shaft 34 is journalled in said frame 33 upon an axis parallel with the axis of the shaft .31; and a third shaft 35 is journalled in said frame upon an axis aligned with the axis. of the shaft 34. A sun gear 36 is :fixed on the shaft 34 and a sun gear 37 .is fixed on the shaft 35. A, differential housing or carrier 38 .isjour:

nalled to rotate upon the axis common to the shafts 34 and 35, and supports planetary gears 39 meshing with the sun gear 36 (Fig. 4) and planetary gears 40 meshing with the sun gear 37 and with the gears 39.

A sprocket 41 is fixed to the shaft 31, a

is fixed to the carrier 38,and a chain 43 provides affixedratio drive connection bet'ween the sprockets 41 and 42.

The differential mechanism thus comprises a first input 1 element 38, a second input element 34 and an output; element 35. If the shaft 34 and the carrier 38 are driven at a common velocity and in the same direction, the shaft 35 will be driven at the same velocityin the same direction. However,-any reduction in the velocity of the carrier 38 relative to that of the shaft 34 will result in a reduction in the velocity of the shaft 3 5, until, when the velocity of the carrier38 is one-half that of the shaft 34, the shaft 35 will be held against rotation. Any further 60 increase in the differential between the velocities of the input elements will result in rotation of the shaft 35 in the opposite direction. Thus, the speed and direction of' rotation of the output element 35 are measured by the differential between the speeds of the input elements.

An expansible V-pulley, indicated generally'by the reference numeral 44, is mounted on the shaft 31, and'comon the shaft 34 and comprises a coned disc 49 fixed to (not shown) at aconstant ratio with respecttothe for sprocket 42:

with the disc 46. A resiliently expansible V-pulley, indicated generally by the reference numeral 48, is mounted 3 said shaft, a mating coned. disc 50 axially adjustable toward and away from the disc 49,. and a spring unit indicated generally by the reference numeral 51, of conventional construction, tending always to press the disc 50 resiliently toward the disc 49. V -belt 52" provides a driving connection between: the pulleys 44 and 48; and it will be seen that this assembly constitutes a' variableratio. driving connection between the shaft 31 and the second input element 34 of the differential gear.

Upon a suitable pivot 53 within the frame 33 there is oscillably mounted a bell crank lever 54, one arm 55 of'which is formed as a yoke engaging the bearing housing 47 on opposite sides of the shaft 31, and the other arm 56 of which is disposed in the path of an actuator element 57. Said element 57 comprises a pin or rod reciprocablymountedin a wall of the frame 33 and provided with adjustable stop collars 58 and 59 limiting its stroke, said pin projecting outside theframe 33 fora purpose later to become apparent.

' A reduction gear, indicated by the reference numeral 60, comprises a worm 61 drivingly connected to the output shaft 35 of the assembly 32-, and a worm wheel 62 mounted on a shaft 63 which projects from the gear housing and externally carries a' sprocket 64 which,

through-a chain- 65, isconnected to, drive a sprocket 66 on the shaft 11'.

The arm 21 includes, or carries, a projection upon which is-formed' a cam surface 67 extending into cooperative engagement with the actuator 57.

When a loaded storage roll 12'is mounted in the frame 10, the arm 21, under the influence of the weight 26, will be in its extreme counter-clockwise position, in which the roller 20 on the axle 19" will be at the extreme lefthand end of. the track 17.. The end of the material on the roll will now be carried over the roller 20 and to the forwarding means 15, and thence to a point of use. When the forwarding means is energized, the shaft 27 will likewise be driven. The parts are so proportioned and designed that the carrier 38 will'thereby be driven at a velocity sufiiciently less than that of the shaft 34 that the roll 12 will be driven at an angular velocity such as to maintain a predetermined degree of tension in the run 16. As material is withdrawn from the mass 13,

the effective diameter of the roll. is decreased. Since the rollis turning, at a constant angular velocity, there is a tendency for the tension in the run 16. of material to increase. At the same time the point of tangency of thesection 14. withthe effective surface of the mass 13 moves gradually toward the right as viewed in Fig. 2. The combined effect of. these two tendencies will. be to increase the horizontal component of the force exerted upon the roller by the material, whereby the tendency of the weight 26 is overcome, and the roller 20 will be moved toward the right along. the trackway 17; Thereby, the arm 21- will be moved in a clockwise direction. The cam- 67 is so designed. that, such movement of the said arm willpermit the actuator 57' to rise, thereby permitting the lever 54 to;move in a clockwise direction and permittingthe disc 4610 move away from the disc 45, all under the influence, of the spring unit 51 which,.

as has been said, is constantly-tending to force the disc 50 toward the, disc 49, thereby squeezing the belt. 52.

outwardly between saiddiscs and pulling it more deeply between the discs 45 and 46. The result of such adjustment, of course,.will be to reduce the speed of the input element 34, thereby. reducing the differential between the speeds of the input elements 34 and 38, and increasing the-speed of the output shaft 35 and of the roll 12.

This adjustment continuesprogressively, as the effective diameter of the mass 13 (roll' 12) progressively decreases, to maintain constant tension upon the run 16 which. is continuously forwarded, at a constant lineal speed, by the forwarding-means 15-.

It will be clear that the illustrated mechanism could be used, also, in a winding. operation. In such. a case, the forwarding means 15 would, of course, move the material toward, instead of away from, the storage roll at a constant velocity; and the control mechanism would operate to reduce the angular velocityof the roll 11 progressively, under the domination of variations, or rather tendencies toward variation, in the tension in the section 16 of the material. The roller 20 would move progressively from its dotted line position toward its solid line position to permit the arm 21 to. move in a. counterclockwise direction, during such winding operation.

The variable-ratio drive means, of course, comprises the pulley pair 44, 48, while the constant-ratio-drive means comprises the sprockets 41 and 42. It will be clear that the sprockets 41 and 42. with the chain 43 are, in many respects, the equivalent of a pair of fixed-ratio pulleys with a connecting belt; and the expression pulley pair, as usedin the appended claims, is intended to include-a pair of sprockets suchas 41 and 42.

We claim as our invention:

1. Means for automatically controlling the rate of rotation of a storage roll for flexible material comprising, in combination with such a roll, alengthof flexiblematerial wound on said roll, means for forwarding said material substantially. in a plane at constant lineal ve locity, a differential gear including a first input element, a second input element, and an output element, means connecting input elements to control the speed of said output element in accordance with the differential between the speeds of saidinputelements, rotary means driven at a constant ratio with respect to said-forwarding means, constant-ratio drive means connecting said rotary means to drive said first inputelement, variable-ratio drive means connecting said rotary means todrive said second input element, an" arm mounted for oscillation about a fixed axis in a common plane with the axis' of said roll, means operatively engaging said arm andbearing against the innersurface of said material: at a point within the sector defined between the current point of tangency ofsaid material with the effective surface of said roll and a plane including the axis of said roll and normal to the plane of movement of said material, means yieldably urging said arm away from saidnormal' plane and toward said current point of' tangency, means connecting said arm to vary the ratio of said variableratio drive means in response to movement of'said' arm,

and means providing a driving connection between said material. wound on said roll, means for. forwarding said material at constant lineal' velocity, a differential gear including a first input element, a second input element, and an output element, means connecting said input elements to control the speedof'said'output element in accordance with the differential between the speeds of the input elements, rotary means driven at a constant. ratio with respect to said forwarding means, constant-ratio. drive means connecting said rotary means to drive said first input element, variable ratiodrive-means connecting said rotary means todrive said second" input element, an arm mounted for oscillation about the axis of said roll a trackway spaced from said axis; said trackway being disposed in a plane substantially parallelwith said axis and said trackway extending in a directiontransverse to the direction of length ofsaid axis, a bearing member supported on said trackway for movement therealong, bearing against the inner surface of said' material at a point within the sector" defined betweenthe current point said bearing member being operativelyconnected with said arm, said arm being yieldably biased away from said normal plane and toward said current point of tangency, means connecting said arm to vary the ratio of said variable-ratio drive means in response to movement of said arm, and means providing a driving connection between said output element and said roll.

3. Means for automatically controlling the rate of rotation of a storage roll for flexible material comprising, in combination with such a roll, a length of flexible material wound on said roll, means for forwarding said material at constant lineal velocity, a differential gear including a first input element, a second input element, and an output element, means connecting said input elements to control the speed of said output element in accordance with the differential between the speeds of said input elements, rotary means driven at a constant ratio with respect to said forwarding means, constantratio drive means connecting said rotary means to drive said first input element, variable-ratio drive means connecting said rotary means to drive said second input element, an element movable oppositely to vary oppositely the drive ratio of said variable-ratio drive means, an arm mounted for oscillation about the axis of said roll, a

trackway spaced from said axis, said trackway being disposed in a plane substantially parallel with said axis and said trackway extending in a direction transverse to the direction of length of said axis, a bearing member supported on said trackway for movement therealong, bearing against the inner surface of said material at a point Within the sector defined 'between the current point of tangency of said material with the effective surface of said roll and a plane including the axis of said roll and normal to the plane of movement of said material, said bearing member being operatively connected with said arm, said arm being yieldably biased away from said normal plane and toward said current point of tangency, means on said arm operatively engaging said actuator to shift the same upon movement of said arm, and means providing a driving connection between said output element and said roll.

4. Means for automatically controlling the rate of rotation of a storage roll for flexible material comprising, in combination with such a roll, a length of flexible material wound on said roll, means for forwarding said material at constant lineal velocity, a differential gear including a first input element, a second input element, and an output element, means connecting said input elements to control the speed of said output element in accordance with the differential between the speeds of said input elements, rotary means driven at a constant ratio with respect to said forwarding means, constantratio drive means connecting said rotary means to drive said first input element, variable-ratio drive means connecting said rotary means to drive said second input element, an arm mounted for oscillation about the axis of said roll, a trackway spaced from said axis, said trackway being disposed in a plane substantially parallel with said axis and said trackway extending in a direction transverse to the direction of length of said axis, an axle supported on said trackway for movement therealong, a roller supported on said axle for free rotation about the axis thereof, said roller bearing against and supporting the inner surface of said material at a point within the sector defined between the current point of tangency of said material with the eifective surface of said roll and a plane including the axis of said roll and normal to the plane of movement of said material, said arm being formed with a longitudinally-extending slot and said axle having operative engagement in said slot, means yieldingly urging said arm away from said normal plane and toward said current point of tangency, means connecting said arm to vary the ratio of said variable-ratio drive means in response to movement of said arm, and means providing a driving connection between said output element and said roll.

5. In a device of the class described, a frame, a storage roll for flexible material journalled in said frame, means on said frame providing a trackway spaced from the axis of said roll and extending transversely relative to said axis, an arm mounted for oscillation about the axis of said roll and extending into proximity to said trackway, a wheeled axle supported on said trackway for movement therealong and operatively connected to said arm, said arm being yieldably biased to hold said axle near one end of said trackway, a roller supported on said axle for free rotation about the axis thereof, said roller bearing against'said flexible material at a point between said roll and said forwarding means and being supported thereby against the bias of said arm, a differential mechanism mounted adjacent said roll axis and including a first input element, a second input element, and an output element, means connecting said input elements to control the speed of said output element in accordance with the differential between the speeds of said input elements, a driven shaft, constant-ratio driving means connecting said shaft to drive said first input element, variable-ratio driving means connecting said shaft to drive said second input element, an actuator shiftable oppositely to vary oppositely the ratio of said variable-ratio driving means, means carried by said arm and operatively connected to shift said actuator upon movement of said arm, and means providing a driving connection between said output element and said roll.

References Cited in the file of this patent UNITED STATES PATENTS 2,175,551 Perry Oct. 10, 1939 2,581,328 Malcom Ian. 1, 1952 2,608,741 Reeves Sept. 2, 1952 2,664,724 Lambach Jan. 5, 1954 FOREIGN PATENTS 235,025 Switzerland Nov. 15, 1944

Images