US2914263A - Winding mechanism - Google Patents

Description

Fi lllllllllllll 54 ATT RNEY v United States Patent ffice i Patented Nov. 24, 1959` WINDING MECHANISM Application March 29, 1954, Serial No. 419,507

2 Claims. (Cl. 242-55.11)

This invention relates to winding mechanism adapted to receive and accumulate a length of flexible material and to maintain tension in the material as it is received and during the winding operation.

Many types of mechanisms perform operations on material in the form of strips, cords, tapes, strings, wire or cable, and at the termination of the operation the material is accumulated and stored on a reel, vbobbin, spindle or cylinder in one or more successive layers. In order to prevent the formation of a loop of material between the mechanism and the take-up reel, tension is maintained by the reels on the material in transit between them and, when the mechanism speed is constant, this involves driving the take-up reel at varying speeds as the diameter of material accumulated thereon varies.

Such take-up reels are commonly associated with motion picture cameras and projectors, wire drawing benches, automatic telegraph tape perforators and transmitters, Wheatstone recorders, rolling mills, and many other types of mechanisms. In all of them the take-up reel has a requirement that when the linear speed of the strip or wire is constant the take-up reel must be made to rotate at speeds varying inversely with the diameter of the material accumulated thereon.

Another equally important requirement for the takeup reel is that upon stopping of the mechanism the reel shall maintain tension on the wire or strip until the mechanism has come to a complete rest. If the take-up reel should stop first, even by a fraction of a second tension would not be maintained in the wire or strip entering it and in some cases slack would be formed causing malfunction.

The formation of slack on stopping can be eliminated by driving both mechanism and the take-up reel from the same mechanical power source. It is, however, convenient in some cases to drive the take-up reel separately because it simplies solution of the variable speed requirement. However it aggravates the requirement that the take-up reel shall not stop before the mechanism. If, for example, the mechanism and the take-up reel are rotated by two separte electric motors, and if when the mechanism is stopped by opening its motor circuit the take-up reel motor circuit is also opened, either the mechanism or the take-up reel may tend to stop first, depending on which has the less stored rotational energy or which has the greater friction. If the mechanism tends to stop first the tension in the strip or wire is maintained until both mechanism and reel stop. If, however, the take-up reel tends to stop first the mechanism will run after the take-up reel has stopped, causing loss of tension, slack, formation of a loop, or pile-up of the material. t

One obvious solution to this difliculty is to employ a slow release relay controlling the take-up motor. The instant invention employs another solution which eliminates the use of the relay and which has been found simpler in some cases.

In brief, the present invention provides a rotatable inertia element` having a relatively large amount of inertia, and a plurality of clutch and coupling devices to connect the driving element, the driven take-up reel and the rotatable element. The driving element stores some rotational energy in the rotatable element while driving the take-up reel, the coupling to the element being such as not to interfere with required rapid acceleration of the take-up reel when it is started from rest. When electric power inputs to the mechanism and to the reel driving element are cut off at the same time, the driven reel either is declutched from the driving element or remains coupled to it if the frictional resistance of the driving element is low enough to permit. In addition the driven reel is clutched to the rotatable element so as to be driven by it. The torque of the reel is then maintained by absorption of energy from the inertia element until the mechanism shall have come to a complete stop.

The principal purpose of this invention is to provide a winding mechanism Vwhich maintains continuous tension on the material wound thereon.

A more specific purpose of this invention is, to provide a winding mechanism which maintains tension on the' material being transferred thereto from a feeding mechanism until the feeding mechanism has come to rest.

A further understanding of this invention may be secured from the detailed description and drawings, in which:

Figure 1 illustrates a motion picture projector including a film strip take-up reel.

Figure 2 depicts a side'view of the take-up reel of Fig. l and associated equipment for controlling the reel in accordance with one embodimentof this invention.

Figure 3 is a detailed View of clutch suitable for use with the embodiment illustrated in Figs. l and 2.

Figure 4 illustrates another embodiment of this in-l vention.

Referring now to Fig. l, a motion picture projector includes a base 11 with projection mechanism 12 secured thereon. The mechanism 12 contains a motor having an electric supply cable 13. Motion picture film to be exhibited is stored in drum 14 on a storage reel, and is drawn off by projector 12. After passage of film 16 through the projector the film is reeled on the take-up reel 1'7 in take-up drum case 18. The take-up reel is driven by a gear motor 19, Fig. 2, through a self-contained speed-reducing gear box 21 at an average reel speed of 70 r.p.m. The motor 19 has a nominal speed of 1700 rpm. and is provided with a shaft at each end, its rotor shaft 22 projecting from the case end opposite to the gear box. The shaft 22 carries a loose flywheel 23 the bore of which forms a sleeve bearing having a running fit on the shaft 22. The flywheel 23 is provided with an overrunning clutch 24 which can transmit power from the ywheel to the shaft but which cannot transmit power from the shaft to the flywheel.

This overrunning clutch may be of any of the numerous Well-known forms, all having the characteristic that the clutch transmits power when the speed of one member tends to be greater than that of the second member, and de clutches when the speed drops below that of the second member. One form of such clutch is illustrated in Fig. 3. The hub 25 of flywheel 23 is bored to form a sleeve bearing having a running fit on shaft 22. This bearing has sufficient friction so that rotation of shaft 22 will gradually bring the flywheel up to shaft speed' but has small enough friction not to load the shaft materially in comparison with the load imposed by the take-up reel. Rotation is in the direction of the arrow 26. The clutch itself is formed of a spring steel five-turn wire helix 27 having a free diameter slightly less than the shaft diameter encircling shaft 22, thus bearing on the shaft with a slight spring pressure. One end of the spring is secured to the hub 24 by a screw 28, the other end being free.

In operation from rest, when shaft 2'2 commences to rotate it tends to turn spring 27 in the direction to loosen it, therefore the spring does not clutch the shaft. The slight friction of the spring on the shaft and friction of the sleeve bearing gradually bring the flywheel up to the same speed as the shaft. When power is removed from shaft 22 the flywheel tends to keep rotating at its attained speed because of its angular momentum which is effectively greater than that of the shaft 22 and attached parts. The shaft speed therefore tends to drop below that of the flywheel. When, however, the shaft speed drops a very small amount below that of the flywheel the relative rotation causes wire '27 to seize the shaft the energy stored in the flywheel is communicated to the shaft, driving it. The shaft 22 in turn applies torque to the take-up reel 17, Fig. 1, motor 19, Fig. 2, having been deenergized, the torque being sulllcient to maintain tension in the lm strip 16 and to continue winding it on the take-up reel until the projector 12 shall have come to a complete stop.

Obviously, in place of the friction drive constituted by the sleeve bearing of flywheel 23, any other form of friction drive may be employed such as the disc type which can be conveniently placed within hub 25. By use of a spring the disc pressure can be adjusted to adjust the time required for the flywheel to attain full speed. It is to be noted that the friction drive of the fly-v wheel through the sleeve bearing by the shaft is entirely distinct from the overrunning clutch wire 27 in both structure and function. The former drives the flywheel from the shaft and the latter drives the shaft from the flywheel.

In thus describing this embodiment of the invention it is assumed that the driving device, such as motor 1-9, has negligible internal friction and therefore can remain coupled after power has been removed. A form of the invention in which the driving device drives through an overrunning clutch, so that this assumption need not be made, is illustrated in Fig. 4. In this form the invention is applied to control of a take-up reel or drum 29 on which a cord or wire 31 is taken up from a mechanism 32. The drum is driven by motive device 33. The mechanism 32 is so driven relative to driving device 33 actuating the take-up drum that the described problem arises.

Driving device l33 drives an overrunning clutch 34 which clutches when the power is applied from shaft 36 and declutches when power is applied from shaft 37. Shaft 37 actuates a speed changing gear 38 in which may be included a slip clutch or a constant torque device as may be required by the dynamic characteristics of drum 29. Bevel gears 39 and 41 connect shaft 37 to shaft 42, although connection may alternatively be made by spur gears or otherwise. Shaft 412 drives a disc 43 which, together with friction wheel 44, comprises a variable speed drive. Wheel 44 is secured to a shaft 46 rotatably bearing a sleeve 47 and having a collar 48 pinned to its end. Between sleeve 47 and collar -48 four links 49, S1, `52 and 53 carry two ilyballs `54 and 56. A spring 57 urges the balls together. A loose ring 58 is rotatably held in a groove in sleeve 47, the ring 58 being secured to the frame. The combination of balls 54 and S6, their links and collars, spring 57 and shaft 46 thus forms an inertial governor. An oil or air dashpot 59 secured by a swivel 61 to shaft 46 retards shaft movement toward the left but does not retard its motion toward the right.

When the driving device 33 and mechanism 32 are at rest, ilyballs 54 and 56 are in their innermost positions, wheel 44 is at its farthest right position and its point of contact with disc 43 is at a very slight distance to the left of the disc center. Upon starting mechanism `32 and driving device 33 the latter applies torque to drum 29 so as to `maintain tension in cord 31. The inertia of the flyballs 54 and 56 does not at starting appreciably load driving device 33 both because they rotate at short radii and because they are driven with great speed reduction and by friction through disc 43 and wheel 44. However, as the llyballs gain angular momentum they move away from each other, extending spring 57 and moving wheel 44 at a rate controlled by dashpot -59 leftward toward the periphery of disc 43, increasing the speed of shaft 46 and of the llyballs themselves.

When, during operation, power is removed from mechanism 32 and driving device 33, the speed of driving device `33 and shaft 36 drops below that of shaft 37 and clutch 34 declutches. Power stored in ilyballs l54 and 56 because of their angular momentum now feeds from them through variable speed wheel 44 and disc 43, shaft 42, bevel gears 39 and 41, and gears 38 to drum 29, maintaining tension on cord 31. As the angular momentum of lyballs S4 and 56 is expended they are drawn together by spring l57. This increases the speed ratio of drive through wheel 44 and disc `413 so that the speed of drum 29 tends to be maintained in spite of decreasing available energy in the tlyballs.

What is claimed is:

1. A winding mechanism comprising, a take-up reel for accumulating and storing elongated flexible material, feeding means feeding said material to said take-up reel, a drive shaft connected to said take-up reel, a motor, an overrunning clutch interconnecting said motor and said drive shaft, said clutch being arranged to apply power in the direction from said motor to said take-up reel, an inertial governor, a wheel and disc speed changing mechanism connected to drive said governor, said speed changing mechanism being connected to said drive shaft at a point intermediate said overrunning clutch and said take-up reel whereby said inertial means drives said take-up reel when the rate of deceleration thereof is greater than the rate of deceleration of said inertial governor.

2. A winding mechanism comprising, a take-up reel for accumulating and storing elongated flexible material, feeding means feeding said material to said take-up reel, a drive shaft for said take-up reel, a motor, an overrunning clutch interconnecting said motor and drive shaft, said clutch being arranged to apply power in the direction from said motor to said take-up reel, an inertial governor, and means coupling said governor to said drive shaft subsequent to said clutch, whereby in one condition of operation of said clutch power is applied from said motor to said take-up reel and said governor and in another condition of operation of said clutch, from said governor to said take-up reel.

References Cited in the file of this patent UNITED STATES PATENTS 1,861,584 Readeker et al .lune 7, 1932 2,098,387 Heine Nov. 9, 1937 2,106,338 Black Jan. 25, 1938 2,113,256 Jeanne Apr. 5, 1938 2,123,084 Tanson July 5, 1938 2,173,048 Von Madaler et al Sept. 12, 1939 2,233,284 Collins Feb. 25, 1941 2,364,148 Kellogg Dec. 5, 1944 2,398,265 Tyler Apr. 9, 1946 2,496,977 Bechle IFeb. 7, 1950 FOREIGN PATENTS 103,863 Australia Mar. l5, 1926

Images