US2422200A - Machine for making grommets - Google Patents

Description

June 17, 1947. w, M LEE 2,422,200

MACHINE "FoR MAKING GROMMETS Filed Ma 22, 1945 FIG. 4

WILLIAM M.' LEE QwLW FIG. 2

Patented June 17, 1947 UNITED STATES PATENT I OFFICE (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 4 Claims.

This invention relates to machines for making grommets and more specifically to machines for forming grommets from continuous lengths of fibrous material.

Heretofore, it has been the practice to make grommets from lengths of fibrous material such as cotton rope by wrapping a length of the material in an open spiral on a mandrel and thenplacing the mandrel in the crotch between the thumb and the forefinger, wrapping the thumb and forefinger about the mandrel, and. either pulling the mandrel in a direction to roll the helices of the fibrous material lengthwise thereof thereby to bring the entire length of material into substantially the same plane in the form of a ring or grommet, or by moving the hand in a direction to push the fibrous material along the mandrel thereby to roll it into grommet shape. This hand method of manufacture is tedious and. slow, and. hence, costly.

It is an object of this invention to provide a machine for carrying out the aforesaid method of making grommets from lengths of fibrous material which will be comparatively simple to operate and with which grommets may be manufactured at a rapid rate.

Accordingly, invention resides in a grommet making machine comprising a mandrel adapted to support a length of fibrous material in an open spiral, means dapted to substantially engage the mandrel at opposite sides thereof, means for moving the mandrel longitudinally progressively to feed the spirally arranged fibrous material toward the first named means, and means for moving the first named means in a direction to cause its surfaces to roll the open helices of the fibrous material together into a grommet on the mandrel. More specifically, the mandrel is provided with means for retaining the fibrous material thereon, an air operated piston is connected, to the mandrel to reciprocate the same longitudinally, and a pair of grooved rubber rolls are arranged to substantially engage the opposite sides of the mandrel, the rolls being rotated'in a direction opposite to the direction of movement of the mandrel by air operated motors. In practice, the terminal end of a length of fibrous material is given a turn about the mandrel close to the rubber rolls and is then wound in an open spiral along the mandrel, that is, away from the rolls, the end of the fibrous material which is connected to the source of material being held taut, hence, there is associated with one of the aforesaid rolls, means for severing the finished grommet from the source of fibrous material.

The invention will now be described with reference to the accompanying drawing, in which:

Fig. 1 is a schematic view of the machine for forming grommets showing a length of cotton rope wound in an open spiral thereon;

Fig, 2-is a detail of one of the rubber rolls showing a groove in its peripherical surface;

Fig. 3 is a perspective view of the grommet making machine;

Fig. 4 is a finished grommet; and

Fig. 5 is a detail view showing a mandrel.

Referring to Fig. 1, the grommet making machine is shown schematically as consisting of a mandrel W, a pair of rolls I2 and [4 arranged to substantially engage the mandrel at opposite sides thereof, a cross head H3 for reciprocating the mandrel in a longitudinal direction between the rolls and a pair of shafts l8 and. 2t" for efiecting rotation of the rolls in a, direction which is opposite to the direction of movement of the mandrel during the grommet forming operation. In manufacture of a grommet with the apparatusoutlined above, a continuous length 22 of cotton rope, sliver, yarn or string or any other fibrous material whether of wool, paper fiber or cellulose fiber is given a turn around the mandrel adjacent to the rolls l2 and M to secure it to the mandrel and then is wrapped in an open spiral downwardly from the rolls toward the end of the mandrel and is held taut while the machine goes through a cycle of forming a grommet such as is illustrated in Fig. 4. The forming operation consists of imparting longitudinal movement to the mandrel with respect to the rolls l2 and M to draw the open spiral of cotton rope toward the rolls l2 and I4. As the mandrel moves through the rolls, the oppositely moving surfaces of these rolls tend to scuff or roll the cotton rope along the surface of the mandrel and to bring the open helices of the rope into substantially the same plane, thereby to form a circular or grommet shaped member. More specifically, the machine as shown in Fig. 3, in perspective, comprises a post 24 secured in an upright position to a base 20, the post having a bent over terminal end 28 to which is attached a cylinder 30. Within the cylinder there is arranged to reciprocate a piston (not shown) to which the mandrel I5? is removably attached for reciprocal motion in a substantially vertical position by air pressure, for example, supplied by hose connection 35. Projecting laterally from opposite sides of the cylinder 39 are a pair of arms 32 to which are attached driving means 34, the specific means shown herein, consisting of air operated motors with hose connections, as indicated at 31 and 38. The driving means 34, however, may be electric motors or any other type of means suitable for the purpose of driving the shafts l8 and 20, The rolls I2 and it preferably are formed of rubber and are grooved, as shown in Fig. 2, so as to embrace the mandrel. These rolls, however, may be made of any suitable material andrmay be covered With-leatheraor'fabric,

While a pair of motors have been shown for driving the rolls l2 and 4, it is also within the scope of the invention to use a single motor and suitable gearing to drive the two rolls or if desired, foot power operated means may beemployed for driving the rolls. While it is possible to employ short lengths of fibrous rope :in zmaking'grommets by securing the rope at both ends to the mandrel, it is preferable to use a continuous length of material and for .this reason, there is provided means for severing the finished grommet from the source of supply when it has been rolled into shape. As-illustrated herein, this is provided for Iby disc shaped cutting member 35 mounted on .thesha'ft of one of the rolls [2 or M preferably for rotary movement therewith, and against which the cotton rope may be held to sever it at the end of the grommet forming operation.

In order to collect the grommets as they are pushed off the end of the mandrel, a container 38 is placed beneath the mandrel on the stand 26 into which they will fall. As indicated, the cutter 36 is of larger diameter-than the adjacent roll M and is disposed in a plane substantially parallel to and adjacent to the .plane which includes said rolls and mandrel. The cutter is thus disposed to readily sever the rope as the mandrel moves between the rolls at the end of the grommet formingoperation.

'The mandrel l is shown as cylindrical in cross section, however, it is possible .to make it of any cross section desired and in order to improve the rolling action, which compacts the fibers and twists the helices together toform the grommet, it is desirable to roughen the surface of the mandrel to some degree, for example, by knurling, grooving or by having a coating on the surface of the mandrel which will afiord some resistance to sliding .of the rope on the surface of the mandrel. Such va coating preferably is of rubbe Fig. 5, but may be leather, fabric or a suitable paint or lacquer.

In operating the machine to form grommets, a continuouslength of cotton rope or analogous material is secured to-the mandrel mat its free end by giving it a twist or suitable lap turn in the known manner around the mandrel adjacent to the rolls [2 and I4 and then wrapping it in an open spiral away from the rolls toward the end of the mandrel. The rope running from the end 7 of :the mandrel to thesource of supply is held taut,

whereupon the operator actuates means, not shown, :acting through air hose connections, as indicated at 35 and 3-1, 38 for causing the piston to .move upwardly in the cylinder '30 and hence the mandrel to be withdrawn from between the rolls :l2 and J4 and from simultaneously causing the rolls to .rotatein-directions so that their surfaces move in directions :opposite to the movement of the mandrel. As soon as the mandrel reaches a point between the rolls where the action of the rolls has formed the grommet and forcedit nearly to the end ofthe'mandrel onits up stroke, the rope being held taut is thus brought into position :against the cutting means 36, thereby tosever the cotton rope and thezcompleted grommet then .drnps into the .container .38. The .ma-

4 chine is then stopped and the rolls cease turning, and the spindle or mandrel drops back to its lower position read for forming the next grommet.

The'invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of zany royalties thereon or therefor.

What is claimed is:

l. A grommet making machine comprising a mandrel adapted to support a length of fibrous material in an open spiral, rolls disposed adjacent the mandrel on opposite sides thereof, means for moving the :mandrel longitudinally progressively to feed the spiral of fibrous material toward and between the rolls and mandrel, means for rotating the rolls in directions to cause a grommet to be rolled from said fibrous material between the surfaces of the rolls and the mandrel, and a cutting member mounted on said machine and disposed adjacent to one of said rolls, said cutting member being so mounted on said machine as to cut the fibrous material on the grommet forming stroke of the mandrel, thereby severing the completed grommet from the remaining fibrous material.

2. A grommet making machine comprising a mandrel adapted to support a length of fibrous material in an open spiral, rolls disposed adjacent the mandrel on opposite sides thereof, means for moving the mandrel longitudinally progressively to feed the spiral of fibrous material toward and between the rolls and mandrel, means'for rotating the rolls in directions to cause agrommet to be rolled from said fibrous material between the surfaces of the rolls and the mandrel, and a cutting membermounted'on said machine and disposed adjacent to one of said rolls, said cutting member being so mounted on said machine as to cut the fibrous material on the grommet forming stroke of the mandrel, thereby severing the completed grommet from the remaining fibrous material, said cutting member being mounted on the shaft of said adjacent roll.

3. A grommet making machine comprising a mandrel adapted to support a length of fibrous material in an open spiral, ,rOllS disposed adjacent the mandrel on opposite sides thereof, means for moving the mandrel longitudinally progressively to feed the spiral of fibrous material toward and between the rolls and mandrel, means for rotating the rolls in directions to cause a grommet to be rolled from said fibrous material between the surfaces of the rolls and the mandrel, and a cutting member mounted on said machine and.

disposed adjacent to one .of said rolls, saidcuttin'g member being somounted on said machine as to cut the fibrous material on the grommet forming stroke of the mandrel, thereby severing the com-' pletedgrommet from the remaining fibrous :material, said cutting.member-comprising a cutting disc of larger diameter .thanithe adjacentroll and being fixedly mounted on the shaft of the adjacent roll for rotation with said roll.'

4. A grommet making machine comprising .a mandrel adapted to support alength of Ifibrous material in an open spiral, rolls disposed adjacent the mandrel on opposite sides thereof, means fo moving the mandrel longitudinall progressively to feed the spiral of fibrous material toward and between the rolls and mandrel, means for rotating the rolls in directions to causeagrommet to berolled from said fibrous material between the surfaces of the rolls and the mandrel, and

a cutting member mounted on said machine and disposed adjacent to one of said rolls, said cutting member being so mounted on said machine as to cut the fibrous material on the grommet forming stroke of the mandrel, thereby severing the completed grommet from the remaining fibrous material, said cutting member being disposed in a plane substantially parallel to and adjacent to the plane including said rolls and mandrel.

WILLIAM M. LEE

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Young Aug. 3, 1920 Lurcott Oct. 24, 1922 Beyea Jan. 26, 1926 Young et al May 21, 1929 Young Dec. 10, 1940

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