US 2051735 A
Description (OCR text may contain errors)
1936. K. MICHELSON 24,
TENSIONING DEVICE FOR FLEXIBLE MEMBERS Filed April 27, 1934 Fig.1.
a/ on Patented Aug. 18, 1936 UNITED STATES PATENT orgies TENSIONING DEVICE FOR FLEXIBLE MEIVIBERS Konstantin Michelson, Tallinn-Reval, Esthonia Application April 27, 1934, Serial No. 722,772 I In Finland April 10, 1933 4 Claims.
My invention relates to tensioning devices for flexible members, such as cables, or the cords connecting telephones, flat irons, lamps, and other electrical appliances, to a system. Such 5 cords are subject to damage as they mostly hang downfreely on account of their length and so get kinked or looped, and finally break. The cords are also very troublesome in the manipulation of the appliances to which they are connected, as they have a tendency to get entangled and must be disentangled before the appliance can be used. v
It is an object of myinvention to eliminate the diificulties involved by the use of such cords so as to prevent breaking and entangling, and other unfavorable occurrences. To this end, in a tensioning device for flexible i members according to my invention, I provide a shaft, means such as a frame in which the shaft is mounted, for supporting the shaft through the member which is to be tensioned, and on this i shaft I arrange a rotary drum for winding the flexible member.
My novel device is so designedthat itcan be connected to the flexible member, or cord, without any alterations in the member, and without disconnecting the member. The device is fitted to any cord or the like by a few manipulations, without disconnecting one end of the cord, and so it may be. fitted, for instance, to existing telephones in which the receiver is permanently connected to the apparatus.
In a preferred embodiment of my invention, the shaft on which the rotary drum is mounted, is carried by a frame equipped with guiding rollers for the flexible member and is supported on the member by means of the rollers.
In the accompanying drawing, a device embodying my invention is illustrated by way of example.
In the drawing Fig. 1 is a plan view, and
Fig. 2 is an elevation of the device,
Fig. 3 is a section on the line III-III in Fig. 2,
Fig. 4 is a section on the line IV--IV in Fig. 3.
Fig. 5 is an axial section of a coiled spring by which the drum is connected tothe shaft.
Fig. 6 is a section on the line VIVI in Fig. 2, and
Fig. '7 illustrates the arrangement of my device on a telephone.
Referring now to the drawing, and first to Figs. 1 to 3, the drum comprises a hollow barrel 2, and a pair of side plates l at opposite ends of the barrel. The side plates l are held against the ends of the barrel .2 by stays 9, Fi and crozes are formed in the side plates for locating the barrel. 'The sidezplates are equipped with central bosses for the reception of ashaft l which is held against rotation in the two members 5 and 5 of a frame, by screws 6. w r
The drum is insulated, or, preferably, made of insulating material, such as compositions known by the trade names of bakelite, galalith, etc.
Housed within the barrel of the drum is a torsion spring 3 which, as best'se'en in Fig. 5, com prises an outer portion 3a, and an inner portion 3b which is arranged co-aXially in'the'outer portion 3a. Theoverall size of the spring is reduced by the co-axial arrangement of its portions. The two portions are wound froma singlewire but they might also be'separate members. a
One end of the spring' '3 is at the upper endof its co -axial inner portion3b, andis connected to the shaft 4 at 3c, Fig. 3. The other'end 3d of the spring is at the upper end of its outer portion 3a, and is attached to one of the stays 9 of the drum. In this manner, the ends'of thespr'ing are anchored to the shaftll and, through the shaft, to the frame 5,-and to the drum,- respectively, and the spring serves for rotating'the drum and for Winding the flexible member or cord ll.
Any suitable means, for instance a hook Hi0, as illustrated in Fig. 4, may be provided for securing the cord II to the drum. Preferably, however, a connection is provided which does not project outwardly from the barrel 2, like the hook Illa, because such a projecting member may interfere with the winding of the cord on the barrel. Preferably, the barrel has a recess or depression III, as also shown in Fig. 4, and a slide Illa which is mounted in grooves lllb at the sides of the recess or depression ill, for partly closing the recess, so as to retain the cord in the recess.
The frame 5, 5' encloses the drum, as shown in Fig. 1, and has two arms at whose ends a grooved roller 6 and a plain roller 1, and a grooved roller 6 and a plain roller 1, respectively, are arranged to rotate about stays, 8, 8a and 8', 8a, respectively. The stays are threaded so that any one of the rollers may be removed after unscrewing its stay. One reach of the cord I I is guided by the rollers 6 and 1, and the other reach by the rollers 6' and l. The individual pairs of rollers are staggered with respect to the central plane l2l2 of the drum, as shown in Fig. 1, in order to effect uniform winding of the individual reaches.
The frame 5, 5 is insulated or, preferably, made of insulating material, like the drum, so that short-circuiting is avoided if the insulation of the cord II is defective. The frame members have a somewhat complicated configuration, with portions having bends or kinks. In order to make the frame members strong enough, notwithstanding their being of insulating material, strengthening ribs are provided at the sharper kinks, for instance at l3 and [4 on the frame member 5 where a rib I5 is formed on the outer side of the frame member, and a rib I6 on its inner side, respectively. Similar ribs are provided at corresponding points of the frame member 5, and elsewhere, as may be required. Portions which are bent less abruptly, for instance the portion which extends from the kink M of frame member 5 to the shaft 4, may be re-inforced by insertions ll of fibrous material, to prevent breaking of the frame members when dropped.
In operation, the stays 8 of the roller 6', and 8a. of the roller 1, are unscrewed, and the rollers 1 and 6 are removed. The cord II is then doubled up to form a loop. Before this is done, the drum must obviously be rotated several times in order to put tension on the spring 3, in conformity with the length of the cord l I. After the cord has been looped, and the loop placed in the recess or depression [0, the: slide Illa is pushed forward to retain the loop which is now locked in its position. The drum is now released and rotated by the reaction of the spring 3a, windmg the two reaches of the cord on the drum from opposite sides. The cord II is placed on-the rollers 6 and I, and the rollers and 6' are reinserted, their stays 8a and .8 being screwed into the frame member 5'. The device is now supported by the cord ll.
Fig. 7 illustrates the arrangement of my device on a telephone. Only the drum is illustrated in Fig. 7. The cord H is attached to the casing 20 of the telephone at one end, and to its receiver 2| at the other end. When the receiver 2| is raised, the cord II is unwound from the drum, and tension is put on the spring 3. When the receiver is returned into its initial position, the spring 3 turns the drum in opposite direction, winding the cord ll uniformly on the drum. The cord is always under tension and the formation of loops, and other undesirable events, are prevented.
1. In a tensioning device for flexible members, a shaft, means for supporting said shaft on the member to be tensioned, a rotary drum on said shaft for winding the member, said drum having a recess for the reception of a portion of member, and a slide on said drum which spans said recess and is mounted for displacement parallel to the axis of said drum, for retaining the member in the recess.
2. A tensioning device for electrical conducting cords and the like, including a shaft supported by the cord, a drum adapted for winding the cord rotatable on the shaft including a hollow cylindrical body, means for detachably connecting the cord to the body of the drum consisting of a longitudinally extending recess depressed in the periphery of the body of the drum, and an arcuate member partially closing the recess and slidably engaged with the walls thereof.
3. A tensioning device for electrical conducting cords and the like, including a shaft supported by the cord, a drum adapted for winding the cord rotatable on the shaft, means for detachably connecting the cord to the drum, and a supporting frame associated with the drum and including a series of bends of varying sizes, reinforcements at the bends, the reinforcements at the larger bends being in the form of strengthening ribs while the reinforcements at the smaller bends consist of fibers embedded in the material of which the frame is formed. 7
4. A tensioning device for electrical conducting cords and the like including a shaft supported by the cord, a drum adapted for winding the cord rotatable on the shaft, means for detachably connecting the cord to the drum, and a single torsion spring formed from a single piece of material and consisting of two parts in coaxial relation to each other, both parts being arranged between the drum and the shaft and also in coaxial relation therewith.