US2174948A

US2174948A - Take-down mechanism

Info

Publication number: US2174948A
Application number: US175972A
Authority: US
Inventors: Raven Reginald Frank; Raynor Harry Avery
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-09-17
Filing date: 1937-11-22
Publication date: 1939-10-03
Anticipated expiration: 1956-10-03

Description

Oct. 3, 1939. R. F. RAVEN E1- 2,174,948

TAKE-DOWN MECHANISM Filed Nov. 22, 1937 5 Sheets-Sheet 1 mmg lmmr K -PAV 69 g 0 5 l/VVEA/TO/QS 57 Y r w 4 ATTORNEYS 1 @HHPaY w/e Oct. 3, 1939. R. F. RAVEN ET AL 2,174,943

CHANISM Filed Nov. 22, 1957 5 Sheets-Sheet 2 Fig,2.

(w m m m m m A 1. JL\

s w w ATTORNEYS Oct; 3, 1939.

R. F. RAVEN ET AL TAKEDOWN MECHANISM Filed Nov. 22, 193'! 5 Sheets-Sheet 3 HA 84 W01 N VE N 7095 ATTORNEYS Oct. 3, 1939. R. F. RAVEN El AL TAKE-DOWN MECHANISM Filed Nov. 22, 1937 5 Sheets-Shet 4 AW w w Q .m

m AAl @IW Oct. 3, 1939. R. F. RAVEN ET AL TAKE-DOWN MECHANISM Filed Nov. 22, 1937 5 Sheets-Sheet 5- I I m 2 F. PA VEN 6 H 4. E4 y/we Patented Oct. 3, 1939 UNITED STATES PATENT OFFIQE TAKE-DOWN MECHANISM Reginald Frank Raven,

Bceston, and Harry Avery Raynor, Wollaton Park, Nottingham,

England 11 Claims.

This application is a continuation-in-part of our co-pending application filed September 16,

1936, Serial No. 101,140, for Corsets and like garments, and the present invention is for improvements in or relating to take-down or drawoff mechanism and is chiefly concerned with fabric take-down or draw-off mechanism suitable for use in knitting machines, although the invention is not restricted in this respect for the mecham nism may be employed in other machines, such for example as looms. More specifically, however, it is an object of the invention to provide fabric take-down mechanism, of a simple construction, suitable for use with fabric the elasticity of which l in the direction of its length, or its resistance to drawing-off, varies across its width, and the mechanism provided by this invention is designed for use in the production of comparatively smalldiameter tubular fabric of this nature, such as tubular fabric for surgical hose.

In the case of a small-diameter tube of fabric it is only practicable to locate the entire fabricgripping mechanism outside the tube. From this it follows that the tube must be flattened between the rollers that grip it, and this flattening in fact has no deleterious effect on the fabric. On the other hand the fact that the double thickness of fabric is gripped between the rollers, one roller making contact with the outer face of one layer of the fabric and the opposing roller making contact with the outer face of the other layer, renders it highly desirable that both rollers shall be driven if the best results are to be obtained.

Therefore the present invention provides fabric take-down or draw-off mechanism, comprising a plurality of pairs of take-down rollers for engaging in their nips different portions in the width of the fabric being drawn-off, whereof the rollers of one pair are co-axial with the rollers of the next pair but whereof the two rollers forming each pair are rotatable independently of those forming the next pair and are connected together for rotation in opposite directions to pass the fabric through the nip between them, means for rotating each pair of rollers, and means for automatically varying the speed of rotation, and therefore the speed at which the fabric engaged by a pair of rollers is drawn-off, in accordance with the linear rate of production, or the resistance to drawing oh. This mechanism is simple, and is eminently well suited for use in a circular knitting machine producing the elastic tubular fabric of small diameter employed, without cutting-out to shape, for surgical hose or the like, in which machine the linear rate of production varies as between different portions in the circumference of the tube (e. g., so that the fabric comes off the machine in a sinuous or curved form).

Conveniently, adjacent co-axial rollers are received on a spindle which is common to them both, Two co-axial pairs of rollers will be found sufficient for small diameter tubular fabric, and the provision of only two pairs simplifies the driving mechanism, for each pair of rollers must be driven independently of the other pair. Hence according to an important subsidiary feature of the invention there are two pairs of the aforesaid rollers, and independent operating means for each pair is located at the outer ends of the rollers (those ends of the co-axial rollers that are adjacent being regarded as the inner ends).

One roller of each pair must be rotated in a clockwise direction, and the other in an anticlockwise direction looking from one end of the mechanism. The best way of achieving this result, while employing two similar sets of operating means, is to apply the drive to the front roller of one pair and the back roller of the other pair (for these two rollers rotate in the same direction when each is viewed from its outer end) and to transmit the drive thence to the other roller of each pair.

There may be for each pair of rollers operating means including a yieldable biassing device that is responsive to the resistance to drawing-off exerted by the fabric. More specifically, the said operating means may include an oscillating driving member and means (e. g., the biassing device aforesaid) for varying the amplitude of its oscillations in accordance with the resistance to drawing-off exerted by the fabric.

This mechanism may comprise, for each pair of rollers, a ratchet wheel, a pawl, positive means for moving said pawl periodically in one direction, and spring means for moving it in the other. Advantageously the spring means is arranged to move the pawl in its operative stroke. Therefore if the resistance exerted by the fabric to drawing off is greater than the effort exerted by the spring upon the pawl the latter is rendered inoperative. That is to say (as will appear from a consideration of the ensuing drawings and the appended description) if the resistance exerted by the fabric is too great to be overcome wholly or in part by the spring, the latter remains in a highlystressed condition and prevents, wholly or in part, the movement of the pawl by the said positive means and nullifies or modifies the action of said pawl. Hence, if the resistance to drawing ofi varies as between two portions in the Width of the fabric, one pair of rollers will continue to Operate to take up that portion of the fabric offering the least resistance, while another pair of rollers remains stationary or operates at a less speed. This permits the mechanism to be applied to a knitting machine that produces a length of fabric which departs radically from the straight, for example fabric which is curved or is sinuous in form.

In order that the invention may be better understood reference will now be made to the accompanying drawings, in which Figure 1 shows a length of tubular fabric with constricted panels at intervals in its length and at diiferent parts of its circumference, it being in connection with knitting machines for producing such fabric that this invention is particularly useful,

Figure 2 is an enlarged view of the fabric.

Figure 3 shows the main parts of one form of take-down or draw-off mechanism according to this invention,

Figure 4 is a plan view in greater detail of a preferred form of the mechanism,

Figure 5 is an elevation thereof,

Figure 6 is a scrap View thereof, partly in section,

Figure 7 is an end view thereof,

Figure 8 is an elevation showing certain parts of a knitting machine for producing the fabric shown in Figs. 1 and 2, and

Figure 9 is a plan view thereof.

By Way of example the improvement will be described as applied to take-down mechanism of the kind described in British patent specification No. 357,323 wherein the fabric is taken down between gripping rollers geared for opposite rotation and racked by pawl and ratchet mechanism comprising a plurality (e. g., two) of ratchet wheels with co-acting pawls spaced around a circle and each pawl being carried by a pivoted arm which is rocked by the travelling engagement of a roller on said arm with a suitably disposed ring or race, the intermittent rocking of the pawl-carrying arms rotating the ratchets and fabric gripping rollers.

In this invention the opposed fabric gripping rollers (Fig. 3) are divided in their length so as to provide two pairs of

rollers

52, 52a, one pair 52 being rotated by one ratchet Wheel 53 and the other pair by a second ratchet wheel 54, the two pairs of rollers being axially aligned on loosely inserted spindle members 55. On the two roller driving spindles carrying the

ratchets

53, 54, are pivotally mounted two

rockers

56, 56a, each rocker carrying at one side of its pivot a roller or its equivalent 5'! and having connected at the opposite side of the pivot a tension spring (biassing spring) 58 anchored to a relatively stationary part. Each rocker also carries a pivoted pawl 59, the two pawls coact- .ing with the

ratchet wheels

53 and 54 respectively. The small rollers 51 on the

rockers

56, 56a extend beneath and are adapted to coact with the under face of a ring or race which is fixed at a suitable inclination to the horizontal or is suitably shaped on its under face so that as the take-down mechanism rotates about a vertical axis, the rockers 56, 5611 are, by virtue of the engagement of the roller elements 51 with said ring 60, pivotally displaced against the influence cf the springs 58 to lower the pawls 59 to the extent of one or more teeth on the

ratchets

53, 54, an opposite pivotal movement being imparted to the rockers by the springs 58 to rack the ratchet wheels as the rollers 51 travel to a higher part of the ring or race 60. It will be appreciated that each time a ratchet is racked, the pair of fabric gripping rollers influenced by said ratchet are rotated to draw-off or takedown the fabric. In this invention the strength or tension of the biassing springs 58 is so determined that, should the resistance to stretch of the fabric in the direction of the stitch wales be greater than the force or effort exerted by a spring, said spring will be tensioned and will be prevented from pivoting the rocker member to effect a racking motion, whereas if the resistance exerted by the fabric being drawn off or taken down is insuificient to overcome the pull of a rocker spring, said spring will pivot the rocker and in so doing rack the draw-off rollers associated therewith. By this means when fabric is being taken down embodying constricted panels or portions A such as are hereinafter described with reference to Figs. 1 and 2, the resistance to draw-off exerted by that half or part of the circumference of the fabric embodying a constricted portion overcomes the influence of the rocker spring 58 and prevents H the appropriate pair of fabric gripping rollers 52a from being rotated; whereas at the other half or part of the circumference of the fabric the other pair of rollers 52 are racked to take down the fabric. Thus it will be appreciated that while the part C of the fabric of a less constricted nature is being taken down at each revolution of the machine, the other part or half at which a constricted panel portion A is passing between the first-mentioned pair of rollers 52a is taken down at a lesser speed seeing that said pair of rollers 52a are racked at less frequent intervals and will only be racked when the resistance to take-down has become sufficiently reduced to permit of the rocker spring 58 operating the ratchet and rotating said pair of rollers 52a.

If the fabric being taken down is of uniform or substantially uniform elasticity throughout its circumference in the direction of the wales then the ratchets appertaining to both pairs of

rollers

52, 52a will be operated with equal frequency.

In the construction shown in Figs. 4 to 7 inclusive the cam ring is divided into two semicircular portions Ella, 60b pivoted at 6| as shown in Fig. 5, oppositely inclined so that two racks are given to the take-down mechanism for every revolution of the machine. The angle of inclination of each half of the cam ring is adjustable, for each half-ring is provided with a trunnion nut 54 that is screwed on to a spindle 62 depending from and rotatably mounted in the base 63 of the machine. A knob 65 is provided for rotating each spindle and associated with this knob there is an indicator 56 to facilitate the adjustment of both halves of the ring to the same angularity. Alternatively means may be provided for simultaneously adjusting both halves. For example the two halves of the ring may be connected by convergent links (as in a toggle) to a common nut mounted on a spindle adjacent to the axis 6|.

In the arrangement illustrated it is convenient to provide a lock nut 61 under each trunnion nut 64.

Each pair of take-down

rollers

52 and 52a are threaded on loose spindles 55 and near their ends are geared together by gears 68 and are mounted in brackets 69 depending from a part H! of the machine that rotates in relation to the and, r

part 63. In order to facilitate the insertion of the fabric the rollers may be moved apart by means of a lever H and mechanism substantially similar to that described with reference to Fig. 4 of patent specification No. 357,323. Screw means indicated at 12 may be provided for adjusting the gap between the pairs of rollers in accordance with the grip desired upon, or the thickness of, the fabric. It will be noticed that the rollers 51 on the rockers or truck levers 56 engage the upper surface of the cam ring 60 and are biased in a downward direction by springs 58.

There is a tendency for each pair of rollers to rotate in the reverse direction under the pull of the fabric. In order to prevent this a second clawker or pawl I3 is associated with each ratchet wheel such as 64 and is drawn into engagement with it by a spring 14.

It is pointed out that in each of the constructions hereinbefore described, the pawl-andratchet driving mechanism for one pair of rollers is identical with that for the other pair, and that the drive is applied to the front roller of one pair and to the back roller of the other pair, and is thence transmitted to the other roller of each pair.

The application of the take-down mechanism to a knitting machine for producing the fabric illustrated in Figs. 1 and 2 will now be described with reference to Figs. 8 and 9. These figures illustrate a circular rib knitting machine. This machine provided with two stitch thread feeders It and H located at diametrically opposite positions and an elastic thread feeder l2 located intermediate of said stitch thread feeders. The cylinder and dial needles of the machine are operated by knitting cams to draw loops from the two stitch threads l3 and M in opposite directions and produce rib knitted fabric therefrom. The needles appertaining to the cylinder and dial may be arranged in any suitable rib disposition, say for example 2 x 1. The elastic thread l5 fed at the feeder I 2 is laid in between the oppositely drawn stitch loops so as to be enclosed by them but not knitted. Advantageously the elastic thread I5 is fed under a suitable degree of tension between opposed truncated conical rollers l6, the degree of tension being adjusted in any suitable manner such as by raising and lowering the guides ll relatively to the rollers [6 by rotation of a screw member it along which a bracket 69 carrying said guides H is adapted to travel. The rotation of the feed rollers l6 and the consequent feeding of the thread i5 is effected from the needle cylinder through the intermediary of intermeshing gears 2i 2| and 22, the firstnamed gear 2% meshing, with a gear wheel rotating with the cylinder, or alternatively with the cylinder needles so as to be rotated thereby and the lastnamed wheel 22 being mounted On the axis of one of the feed rollers It.

At one or more positions in the length of the tube or garment being knitted a predetermined batch of successive or adjacent needles of one set, less than the complete set, are rendered inactive at one of the stitch thread feeders, while at another position or positions in the circumference of the tube or garment a different batch of successive or adjacent needles can be rendered inactive at the other stitch thread feeder. Advantageously the batch or batches of needles rendered inactive at predetermined times appertain to the cylinder needles, the full complement of dial needles being continuously operated at each feed. Assuming for example that a surgical hose is being knitted such as is shown in Fig. 1, during the knitting of a panel portion A at the top and back of the calf or at the back of the knee, a batch of the cylinder needles which would normally take thread and knit at said portion is caused to miss at one feeder for several successive courses, all of the needles meanwhile functioning to knit in the normal manner around the remaining part of the circumference of the fabric. As knitting progresses the inactive cylinder needles are again brought into operation and at another position in the length of the hose, say for example at the instep portion, another batch of the cylinder needles diametrically opposed to the last named batch is temporarily rendered inactive at the second feeder so as to produce the panel B. This results in the elastic thread l5 being laid more frequently or being more closely pitched in the panel portions A and 13, thereby constricting the hose at these panel portions and shaping or curving same. During the knitting of the remaining part C of the hose the full complement of the needles of both sets take thread and knit at both of the stitch thread feeders.

The batch or batches of needles may be rendered inactive in numerous ways, say for example by withdrawing a feeder from operation while said batch of needles passes the same, or by maintaining the needles in a retracted position so as not to take thread.

We claim:

1. Fabric take-down or draw-off mechanism, comprising a plurality of pairs of rollers for engaging in their nips different portions in the width of the fabric being drawn ofi, whereof eac roller of one pair has its axis parallel to the axis of a roller of the next pair, a support for the rollers, means connecting the two rollers of each pair together for rotation in opposite directions, and driving means for each pair of rollers, each of which driving means comprises a yielding member which yields in response to resistance to rotation of said rollers.

2. Fabric take-down or draw-off mechanism, comprising a plurality of pairs of rollers for engaging in their nips different portions in the width of the fabric being drawn off, each pair consisting of a front roller and a back roller, means supporting the rollers with the axes of the front rollers in one plane and the axis of each of the back rollers parallel to the axes of the corresponding front roller in a plane parallel to said first plane, means connecting the front and back rollers of each pair together for rotation in opposite directions to pass the fabric through their nip, and means for rotating each pair of rollers independently, including means for automatically varying the speed of rotation of one pair in relation to that of the remainder in response to variation in the resistance to take off.

3. Fabric draw-off or take-down mechanism, comprising a plurality of independently-rotatable pairs of draw-off rollers which pairs are arranged to engage different portions in the width of the fabric, said width lying substantially in a plane, and the rollers constituting each pair being connected together for rotation in opposite directions to pass the fabric through the nip between them, a ratchet wheel connected to a roller of one pair and another ratchet wheel connected to a roller of the other pair, a pawl for moving each ratchet wheel to rotate the associated rollers, means for intermittently moving said pawls independently of one another in the return direction of their stroke, and spring means for moving said pawls in the operative direction of their stroke.

4. Draw-off mechanism for drawing off a flat web of fabric comprising two pairs of rollers, which pairs of rollers extend across different portions in the width of the fabric being drawn off and have their nips lying substantially in a common plane, means connecting the rollers of a pair together for rotation in opposite directions to draw said fabric flatly through thenips of the rollers in said plane, and operating mechanism for each pair of rollers, which operating mechanism comprises a ratchet wheel, a pawl co-operating therewith, spring means for moving said pawl in its operative stroke, and positive means for moving the pawl in its inoperative stroke and for simultaneously stressing said spring means.

5. In a circular knitting machine for knitting tubular elastic fabric including local areas, extending over only a portion of the circumference, which areas are of decreased elasticity or are produced at a lesser linear rate of production, draw-off mechanism for drawing off the tube in flattened form which mechanism comprises a plurality of pairs of rollers for accommodating between them the entire width of the flattened tube, at least one pair of which rollers receives the said areas as the fabric passes from the needles, a support for the rollers, means connecting the two rollers of each pair together for rotation in opposite directions, and driving means for the rollers including means for driving said one pair independently of the other rollers, including means for automatically changing the rate of drive of said one pair in response to change in those characteristics h-ereinbefore mentioned of the area taken down by said pair.

6. In the combination claimed in claim 5, an annular member within which the rollers are located, which member lies in a plane transverse to the direction of take-off and to the axis of the machine, means for effecting relative rotation about said axis between the rollers as a whole and said member, a part movable to and fro and connected to said pair of rollers to drive them during its movement in one direction, means upon said annular member for moving said part in one direction upon the aforesaid relative rotation, and a spring for moving said part in the reverse direction.

'7. Fabric take-down or draw-off mechanism, comprising a plurality of pairs of take-down rollers for engaging in their nips different portions in the width of the fabric being drawn-off", whereof the rollers of one pair are co-axial with the rollers of the next pair but whereof the two rollers forming each pair are rotatable independently of those forming the next pair and are connected together for rotation in opposite directions to pass the fabric through the nip between them, and means for rotating each pair of rollers, including means for automatically varying the speed of rotation, and therefore the speed at which the fabric engaged by a pair of rollers is drawn-off, in accordance with the linear rate of production, or the resistance to drawing-off.

8. Mechanism according to claim 7, comprising spindles, each common to adjacent co-axial rollers and each having said adjacent co-axial rollers received thereon.

9. Fabric take-down or draw-off mechanism, comprising two pairs of take-down rollers for engaging in their nips diiferent portions in the width of the fabric being drawn off, whereof the rollers of one pair are coaxial with the rollers of the other pair but whereof the two r011- ers forming each pair are rotatable independently of those forming the other pair, a support for the rollers, means connecting together the rollers forming each pair for rotation in opposite directions to pass the fabric through the nip between them, and independent operating means for each pair of rollers, located at the outer ends thereof, for rotating said rollers, including means for varying the take-up speed of each pair of rollers in accordance with the. linear rate of production of that part of the fabric engaged by said pair.

10. Fabric take-down or draw-off mechanism, comprising a plurality of pairs of rollers for engaging in their nips different portions in the width of the fabric being drawn off, each pair consisting of a front roller and a back roller, means supporting the rollers with the axes of the front rollers in one plane and the axis of each of the back rollers parallel to the, axis of the front roller, means connecting the front and back rollers of each pair together for rotation in opposite directions to pass the fabric through their nip, an inclined annular cam member rotatable relatively to the rollers about an axis which is substantially central of the length of the rollers and is normal to the roller axes, means for effecting said relative rotation, and spring-returned pawl-and-ratchet mechanism operated by said cam member in its rotation to drive each pair of rollers independently, which mechanism includes means for automatically varying the speed of rotation of one pair of rollers in relation to that of the remainder in response to variation in the resistance of take-off.

11. Fabric take-down or draw-off mechanism, comprising a. plurality of pairs of rollers for engaging in their nips different portions in the width of the fabric being drawn off", each pair consisting of a front roller and a back roller, means supporting the rollers with the axes of the front rollers in one plane and the axis of each of the back rollers parallel to the axis of the front roller, means connecting the front and back rollers of each pair together for rotation in opposite directions to pass the fabric through their nip, a cam-ring comprising two opposite inclined halves, means for effecting relative rotation between said ring and rollers about an axis which is substantially central of and normal to the axes of the rollers, and means for rotating each pair of rollers independently including pawland-ratchet mechanism operated by said ring in said relative rotation and means for automatically varying the speed of rotation of one pair of rollers in relation to that of the remainder in response to variation in the resistance to take-off.

R. FRANK RAVEN. H. A. RAYNOR.