US2753678A

US2753678A - Method and apparatus for making grommets

Info

Publication number: US2753678A
Application number: US334694A
Authority: US
Inventors: Harry J Hansen; Arvin P Wiedemann
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1953-02-02
Filing date: 1953-02-02
Publication date: 1956-07-10
Anticipated expiration: 1973-07-10

Description

July 1o, 1956 H. J. HANSEN ETA; 2,753,678

METHOD AND lAPPARATUS FOR MAKING GROMMETS Filed Feb. 2, 1953 2 SheeS-Sheet l lllllu July 10, 1956 H. J. HANSEN ETAL 2,753,678

METHOD AND APPARATUS FOR MAKING GROMMETS Filed Feb. 2, 1953 2 sheets-sheet 2 FISE. il 7@ METHOD AND APPARATUS FOR MAKING GROMlVIETS Harry J. Hansen, Hamden, andy Arvin P. Wiedemann,

North Haven, Cnn., assigliors to United States SteelI Corporation, a corporation of New Jersey Application February 2, 1953, Serial No; 334,694l 7 Claims. (Cl..5-2`1) used in forming a grommet, other wire structures, such as` a single wire, rope or plastic mono-lament may also be used. For the. purposes of clarity and simplicity in describing the present invention, the element of which the grommet is formed will hereinafter be referredto as a strand. l

In a common grommet, they endporti'ons of :the single length of strand of which the grommet is made are straight, that is, free of any set or helical formation, andforin the core and tuck of the grommet. Themicl-portion ofthe strand has a preformed helicalset and forms the` outer layers.

An object of our yinvention is to provide an apparatus o and method for making a grommet from a single length of wire strand.

It is a further object of our invention to providefanV apparatus and method .formakinga grommet from a` single length of strand Vhaving av preformed helically set mid-portion and straightend portions.

These and other objects will becomefmore apparent after referring to the following specification adattached drawings, in which: p

Figure 1 is a side elevation of our invention;y

Figure 2 is an end elevationl of Figure 1;y p

Figure 3 is an enlarged .side elevation of a latchng mechanism;

Figure 4 is an end ,elevation of Figure 3; l

Figure 5 is a detail showing the upper half of a die block; n

Figure 6 is anl end elevation .of FigureS;

Figure 7 is a detail showing the l'o'wer half of a die block; n

Figure 8 i-s an end. elevationof` Figure 7'; and u Figure.9 is a viewshowing arrarrangement-ofthe straight and helical sections of a strandt Referring more particularly to the drawings, reference numeral 2 indicates a base on which two pairs of grooved rollers 4 and 6 are mounted in bearings 8 and 10 respectively. An interconnecting drive shaft 12 connects and drives the rollers 4. The drive shaft is rotated by means of a sprocket 14, which is rigidly mounted on the shaft intermediate its ends. A chain 16 connects the sprocket 14 with a sprocket 18 which is mounted on the shaft 20 of a speed reducer 22. The speed reducer, in turn, is operatively connected with a variable speed, reversible motor 24.

Rotor plates or

wheels

26 and 28 are rotatively mounted on the pairs of rollers as best shown in Figure 1. A cradle or cage 30 is rotatively supported between the

plates

26 and 28 for holding a supply reel 32 upon which lCe may be coiled a wire strand S of predeterminedlength to be formed into a grommet.

The ends of the cradle 30 are rotatively supported in

bearings

34 and 36 in

` plates

26 and 28,V respectively; by means of shafts 35-and 37 which project from the' .ends of the( cradle.- Shaft 377, which fits into the :bearing 36, is hollow. Each of the shafts 3 5 and 37 project outwardly beyond the .plates a short distance and have outer- Inner flanges 411 'and 43 are:

flanges 39 fittedy thereon. v fitted around each ofthe shafts 35 and37, respectively, inwardly of the plates 26 and 2S. y

The

plates

26 and 28 may beconnected together for unitary rotation by means offtie bars 38 and nuts 40.

The two side members 42 of the cradle 30 vare pro= vided with matching slots or notches `44 for supportingthe axial shaft 46 of the reel 32. A An angular plate extension 48 may be provided o-n each ofthe side members 42 adjacent and .below the slots 44`for pivotallymounting latches 50. Latches 50 function to keep the shaft 4,6 in position while the machine is operating. Latch 50, is maintained in operatingposition'by means of helical tension springs 52. A pair of small rollers 54'may be provided in opposed position,y one on each side. of the side members 42, adjacent'each of theslots 44 to engage and supportthe reel` shaft 46 and thus insure smooth rotation of the supply reel 32 asstrand is withdrawn therefrom.I y j A brace 56 extends between theside members 42 intermediate the slots 44 and the plateZS. A counterweight 5S is suspended from the brace 56 and another counter Weight 58 issuspended from the inner llange 41 for preventing rotation of thecradle 30 when platesA 2'6 andi-128i are rotated. A p A brake. mechanism 60 is provided. for applyingsuflicient restraint against rotation of the supply reel.3 2so that the reel will .not rotate unless the strandk S is being pulled. The brake mechanism includes a .pairof brake wheels 62 one of which is ltted on the supply reel shaft adjacent each side of the reel. A brake' rope 64frictionally. engages a substantial portion of the .gro'ov'ed periphery of each wheel. Each of the brake Vropes is anchored at one end to brackets 66'ailiXed to side'memf b'ers 42. Their other ends are adjustablyy attached to the` lower ends of vbrake levers 67 which are pivotally mounted on the side members 42. The upper end of each lever isrv connected with an adjusting screw 68 which,at its opposite end', threadingly engages a screw plate 70 which is mounted on the brace 56. Each of the brake wheels is. rigidly connected with its respective sidelof the supply reel-by means of integral pegs 72 .which Vproject from the yside ofy the.

brake wheels and iitint'osuitable holes in the sides of the' supply reel as best shown inv Figure 4. A

Die blocks 74 and. '74" are tted at a pointadjacent the periphery ofthe plates 26- and 2K8 respectively. The

upper halves

76 and 76"- of each ofthe die blocks'A is.

removable for a'purposewhich will become apparent as this desc''ptionproceeds.. y p l l y In operation, apredetermined'flength of .strand...-liaving` straight' end portions" S1l and S3A and 'a preformed helical'l mid-portion S2 is coiled about the supply reel 32, and the supply reel is mounted in the cradle 30 as described above.

Figure 9 illustrates a preferred arrangement of the straight and helical sections of the strand which is to be assembled into a grommet. Section S1 is straight and is equal in length to the circumference of the nished grommet desired. This straight portion will form the core C of the grommet. The length of the section S2 is equal to that of the circumference multiplied by the number of times the strand is to be wrapped about itself, multiplied by the secant of the angle of lay of the strands with respect to an axis coincident with the core of the 3 grommet. The number of times a strand is wrapped about itself in forming a grommet is usually -six but may be more or less than this number as desired. The end portion S3 is a relatively short length of straight strand which is tucked or rolled into the center of the grommet at its completion.

After the reel 32 bearing the coil of the strand S has been properly positioned in the cradle 30, the strand is passed manually from the reel through the central opening of the shaft 37 outwardly of the plate 2S and looped out and around the cradle as shown in Figure l, and then passed through the die block 74, then through the die block 74. A loop is then formed by seizing the lead end of the strand to the irst end P of the helically preformed mid-portion S2. The loop thus formed is of the same circumferential dimension as and constitutes the core C of the grommet to be made. After the loop has been thus formed, the motor 24 is actuated to rotate the

plates

26 and 28 which causes the loop to be thrown as a hoop around the cradle and the plates. As the plates rotate, the loop is continuously pulled manually in an axial direction from the plate 26 to plate 28 through the dies whereby the strand issuing from the plate 28 is laid on the core in helical convolutions. This is continued until the desired number of layers of helical convolutions have been laid about lthe core.

When the last end S3 of the strand emerges from the plate 28, the layers of helical convolutions are parted and a portion of the core adjacent the last end S3 is cut out and the end S3 is inserted in its place.

On completion of the grommet as described, the remov able portions 76 and 76' of the dies 74 and 74 are removed to permit removal of the grommet from the machine.

Although we have shown and described but one embodiment of our invention, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

We claim:

1. Apparatus for making grommets comprising a pair of wheelsrotatively disposed coaxially and in spaced relation to each other, a pair of supporting rollers engaging the periphery of each wheel, a frame vextending between and supported by said wheels for rotation with respect thereto, means attached to said frame tending to hold the same stationary when the wheels are turned, and means carried by said frame for supporting a reel, one of said wheels having a central eye through which strand coiled on said reel may be drawn off, said wheels having substantially aligned openings adjacent their periphery to receive said strand.

2. Apparatus for making grommets comprising a pair of vertical Wheels rotatively disposed coaxially and in spaced relation to each other, a pair of spaced supporting rollers below said wheels engaging the periphery thereof, a horizontal frame extending between and supported by said wheels for rotation with respect thereto, a weight supported by said frame below the axis thereof, said weight tending to hold said frame stationary when vthe wheels are turned, means carried by said frame for supporting a reel on a normally horizontal axis parallel to said wheels, one of said wheels having a central eye 'through which strand coiled on said reel may be drawn off, said wheels having substantially aligned openings adjacent their periphery to receive said strand, and means connected with said wheels for causing the same to rotate in synchronism.

3. Apparatus for making grommets as dened by claim 2 characterized by said frame having a hole in the end thereof adjacent said one of said wheels in alignment with said eye.

4. In a method of making a grommet, the steps including mounting a coil of wire strand of predetermined length between a pair of spaced coaxial wheels, threading one end of the strand through a central eye in one of the wheels, drawing out the strand to form a loop lying laterally of said wheels, threading said one end through the peripheries of the two wheels and seizing said one end into contact with the portion of the strand issuing from said eye to form a core in the shape of a closed loop, turning said wheels and throwing the loop as a hoop around the wheels and coil at each revolution of the wheels to wind the strand issuing from said eye about said core, and continuously pulling the core in an axial direction through the wheels whereby the strand issuing from the eye is laid on the core in helical convolutions.

5. In a method of making a grommet as defined by claim 4 including the steps of removing a portion of the core adjacent said one end, and inserting the other end of the strand in the space thus left vacant.

6. In a method of making a grommet, the steps including mounting a coil of wire strand between a pair of spaced coaxial wheels, said strand having a length necessary to form a grommet of the desired circumference, said strand having a helical formation except for a portion at each end thereof, one of said end portions having a length substantially equal to the circumference of the grommet to be formed, threading said last named end of the strand through a central eye in one of the wheels, drawing out the nonhelical end portion of the strand to form a loop lying laterally of said wheels, threading said last named end portion through the peripheries of the two wheels and seizing said end into contact with the helically formed portion of the strand issuing from said eye to form a core in the shape of a closed loop, turning said wheels and throwing the loop as a hoop around the wheels and coil at each revolution of the wheels to wind the strand issuing from said eye about said core, and continuously pulling the core in an axial direction through the wheels whereby the strand issuing from the eye is laid on the core in helical convolutions.

7. In a method of making a grommet as dened by claim 6 including the steps of removing a portion of the core adjacent said iirst named end, and inserting the other end of the strand in the space thus left vacant.

References Cited in the file of this patent UNITED STATES PATENTS 1,389,699 Rivett Sept. 6, 1921 1,457,691 Bull June 5, 1923 1,479,900 Dorner Jan. 8, 1924 1,587,856 Reed June 8, 1926