US2691880A

US2691880A - Rib hole-detector for revolving and stationary head rib knitting machines

Info

Publication number: US2691880A
Application number: US305860A
Authority: US
Inventors: Vossen Edward
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-08-22
Filing date: 1952-08-22
Publication date: 1954-10-19
Anticipated expiration: 1971-10-19

Description

Oct. 19, 1954 E. vossEN RIB HOLE-DETECTOR FOR REVOLVING AND STATIONARY HEAD RIB KNITTING MACHINES 3 Sheets-Sheet 1 Filed Aug. 22, 1952 ll l llbhl nulmlm N. m5 m A TIDE/V5) Oct. 19, 1954 v E. VOSSEN RIB HOLE-DETECTOR FOR REVOLVING AND STATIONARY HEAD RIB KNITTING MACHINES I 3 Sheets-Sheet 2 Filed Aug. 22, 1952 HOV TRANSFORMER 2 3 /3 R E L L l\ O R T N 0 c INVENTOR fDW/MD V0551 ATT NEY Oct. 19, 1954 E. VOSSEN 2,691,880

RIB HOLE-DETECTOR FOR REVOLVING AND STATIONARY HEAD RIB KNITTING MACHINES Filed Aug. 22, 1952 :s Shee ts-Sheet 3 I |l256 M 252 fHWflED .VOSSEN.

Patented Oct. 19, 1954 UNITED STATES PATENT OFFICE RIB HOLE-DETECTOR FOR REVOLVING AND STATIONARY HEAD RIB KNITTING MA- CHINES 14 Claims. -1

This invention relates to a rib hole-detector for revolving and stationary head rib knitting machines. It also relates to the stop-motion devices which are associated with said hole-detector and which said hole-detector actuates in order to stop said rib knitting machines upon the detection of a hole or similar defect in the knitted fabric.

The rib hole-detector which is herein described and claimed is applicable to three kinds of rib knitting machines. One of these knitting machines is provided with a revolving head. In this machine the knitted fabric is stationary in the sense that it does not revolve. The second machine is provided with a stationary head and here, of course, the knitted fabric does revolve. This machine has no take-up arms. The third machine is also provided with a stationary head but in addition it is equipped with vertical revolving take-up arms. In this machine the knitted fabric revolves with the revolving takeup arms. All three machines may be grouped under the broad heading or classification of circular knitting machines.

The rib hole-detector which comprises the present invention is universally adaptable to all three knitting machines above described. When it is installed in the stationary head rib knitting machines where the knitted fabric revolves, it is held in a stationary position. When it is installed in the revolving head rib knitting machine where the knitted fabric is stationary, it is made to revolve with the revolving head and relative to the knitted fabric. In all cases, the rib holedetector is mounted within the knitted fabric tube and its action is directed radially outwardly.

The rib hole-detector herein claimed may also be made to operate from the outside of the knitted fabric tube radially inwardly, if this should be desired. This would particularly be true where the knitted fabric revolves and in such case the rib hole-detector would be mounted stationary on the outside of the knitted tube.

More specifically, the rib hole-detector which comprises this invention includes two basic elements: The first is a double ring frame which engages the knitted fabric to spread it taut for the hole detection process. The second is a holedetector assembly which includes a plurality of probes or feelers which engage the knitted fabric in the area which is spread taut by the double ring frame. In some cases, the double ring frame and the hole-detector assembly are mounted together, the latter being supported by the former. In other cases, the double ring frame may be mounted within the knitted tube and the hole-detector assembly may be mounted outside of the tube. When the hole-detector assembly is mounted within the tube, its probes or feelers press radially outwardly against the taut area of the tube. Where the hole-detector assembly is mounted on the outside of the knitted tube, its probes or feelers press radially inwardly against said taut area.

In all cases an electric switch mechanism is provided for stopping the knitting machine when a hole or similar defect is encountered and detected by one of the probes or feelers of the rib hole-detector. This switch mechanism is mounted on the outside of the knitted tube. Hence, it may be incorporated into the rib hole-detector when said detector is mounted outside said knitted tube but it must constitute a completely separate and independent device when the rib hole-detector is mounted within the knitted tube.

In the latter case it is necessary to provide an actuating mechanism between the rib hole-detector on the inside of the knitted tube and the switch mechanism on the outside thereof. This actuating mechanism comprises two elements: one is mounted within the tube and the other is mounted outside of the tube. The inner element is actuated by the hole-detector. The outer element is actuated by the inner element. The switch mechanism is actuated by the outer element. Thus a chain reaction is set up when a hole or flaw is detected in the fabric, beginning within the knitted tube, permeating or passing through the wall of said tube, and ending outside of the tube. The inner element includes a bumper or plunger which is normally in retracted position. It is always under the influence of a spring, however, which tends to urge it radially outwardly and into engagement with the taut area of the knitted tube. A trigger mechanism is also included which releases said bumper or plunger when a hole or other flaw is detected in the knitted tube. Upon the happening of this occurrence, the bumper or plunger shoots radially outwardly against the knitted tube, distorting or stretching it sufiiciently to enable said bumper or plunger to project beyond the double ring frame. In this position, the bumper or plunger encounters an outside arm or the like which constitutes the outside element above mentioned and dislodges it from its normal or inoperative position. This has the effect of actuating the switch mechanism and stopping the machine.

Where the switch mechanism and the hole-detector are mounted together in a single assembly, there is no need for an actuating mechanism of the type last above described. Instead, the holedetector acts directly upon the switch mechanism immediately and automatically upon the detection of a hole or other flaw in the knitted material.

In both cases last mentioned, that is, in the case of the switch mechanism and the hole-detector being mounted together to form a single assembly and in the case of the hole-detector being mounted within the knitted tube and the switch mechanism being mounted outside of the knitted tube, r e-setting means is provided in order to start the knitting machine and to reactivate the hole-detecting mechanism. In the case of the hole-detector and switch mechanism being incorporated into a single assembly, a manually operated handle is provided which is connected both to the hole-detector and to the switch mechanism. All that need be done to reset said hole-detector and said switch mechanism is to pull upon the handle. This can very readily be done since in such ase, the hole-detector and switch mechanism assembly are located outside of the knitted tube within convenient reach of the operator of the machine. In the other case, the bumper or plunger may be engaged from the outside of the knitted tube in order to reset the hole-detector which is located within the tube. This is very simply done by merely pressing upon said bumper or plunger until it regains its .retracted position. Similarly, the arm on the outside of the knitted tube which the bumper or plunger engages through the knitted material when a hole is encountered is simply swung hack to its normal position where it may be engaged by said bumper or plunger. This has the effect of re-setting the switch mechanism which in this case .is also located outside of the knitted tube.

The rib hole-detector herein described and claimed aifords many important advantages and possesses many important features. Among these advantages and features may be listed the following:

1. The double ring frame which engages the knitted material and holds it in proper position and in proper condition for the hole-detecting process is an extremely important element. In the first place, it takes the place of the conventional spreader rings which are today employed for the same purpose. These spreader rings are made in various sizes to fit the various sizes of knitted tubes. Each tube requires .a spreader ring of corresponding size and a spreader ring made for any one size of knitted tube cannot be used for any other size of knitted tube. In the present invention, on the other hand, a single size double ring frame may be employed in connection with knitted tubes of every conventional diameter. It should of course be small enough to enter the smallest tube and this is the only prerequisite to its universal use. If it fits the smallest tube, it will fit all of the larger tubes.

It is not essential that the double ring frame be .concentric with the knitted tube. It suflices that the curvature of .the double ring frame approximate the curvature of the knitted tube. An important aspect of this double ring frame is its adjustability relative to the tubular material. It;

may be shifted toward or away from the knitted tube in order to compensate for the various sizes of knitted tube which may be encountered.

2. The adjustable feature of the double ring condition. In other words, the knitted material which at "any particular moment -is disposed between the two rings of the frame constitutes a relatively wide belt or zone which is maintained by said rings in taut condition. A taut zone or belt of this character cannot be achieved by the single spreader rings of the prior art.

4. A further advantage resides in the fact that the two rings of the double ring frame are offset from each other to conform to the taper of the knitted tube. It is well known that the knitted tubes which circular knitting machines produce are not perfectly cylindrical in shape. Instead, they taper inwardly from relatively large proportions at their upper end to relatively small proportions at their lower end. It is this taper to which the double ring frame of the present invention conforms.

5. Still another important feature is the vertical bar which links the two rings immediately adjacent the series :of probes or feelers which said double ring frame supports. This vertical bar precisely positions the taut belt of the knitted material relative to the probes or feelers. Said vertical bar is inclined to correspond to the .taper of the knitted tube, just as.

the two rings of the double ring frame are offset for the same purpose. The vertical bar cooperates with the two rings of said frame to hold the knitted material so precisely in place that it is possible to set the probes or feelers most accurately and sensitively relative to said knitted material. This is essential to the precise functioning of the apparatus herein claimed. The vertical bar also serves another purpose: it helps prevent the knitted material from being pushed inwardly beyond the range of its normal stretch or elasticity when the bumper or plunger above mentioned is returned to its retracted inoperative position.

6. An important advantage of the double ring frame is the double bearing which the two rings provide for the hole detecting mechanism, both when the mechanism is stationary and when it is in motion. The double bearing renders it .possible to set the hole detecting mechanism very precisely relative to the knitted material and the double bearing will maintain such precise setting or adjustment indefinitely.

7. The switch mechanism in the present device also provides important advantages over the prior art. It performs two functions: in the first place, it acts as a switch to stop the machine as soon as a hole or other similar defect is detected. In the second place, it serves as a cutoff switch which disconnects. the unit from the knock-off controller. This is important because .the hole detecting mechanism would otherwise keep on knocking 01f the machine when the fabric is found to be faulty over a relatively large area, whereas this feature enables the operator of the machine to render the hole detecting mechanism inoperative until the fabric runs whole again.

frame is important for an entirely different pur- Once the fabric runs clear of defects, the switch mechanism may be re-set to its normal position, ready to detect other defects in the fabric.

Preferred forms of this invention are shown in the accompanying drawing in which:

Fig. '1 is a vertical section through a revolving head rib knitting machine and the knitted tube which it produces, showing a rib-hole detector made in accordance with one form of this invention, said hole-detector being mounted within the knitted tube for revolving movement with the head of said knitting machine.

Fig. 2 is a fragmentary top view thereof.

Fig. 3 is a view similar to that of Fig. 2 but showing one of the probes or feelers caught in a hole in the knitted fabric and showing the bumper or plunger in forwardly projecting position as a result thereof.

Fig. 4 is an enlarged view of the hole detecting mechanism following its detection of a hole and showing the bumper or plunger in its forwardly projecting position in engagement with the knitted fabric.

Fig. 5 is a fragmentary enlarged front view of said hole detector.

Fig. 6 is a fragmentary vertical section showing the hole detecting mechanism within the knitted tube and the switch mechanism outside of the knitted tube which is actuated by the hole detecting mechanism when a hole is detected in the fabric.

Fig. 6A is a fragmentary top view of the mechanism shown in Fig. 6, but showing that the bumper or plunger may be disposed on the opposite side of the hole detector from the side which it occupies in the preceding figures of the drawing, said view being taken on the line 6A-6A of Fig. 6.

Fig. 6B is a sectional view showing the hollow spindle or shaft of another type of knitting machine having a revolving head and showing a switch mechanism mounted within the knitted tube and connected to the stop motion mechanism by means of a conductor which extends through said hollow spindle or shaft.

Fig. '7 is a top view of a hole detector made in accordance with a second form of this invention, showing it in engagement with the outside of a knitted tube which is produced by a stationary head rib knitting machine.

Fig. 8 is an enlarged front end view of said hole detector, looking in the direction of

arrows

8, 8 of Fig '7.

Fig. 9 is an enlarged side view of said hole detector, showing the switch mechanism theron.

Fig. 10 is a view similar to that of Fig. 9 but showing the switch mechanism in closed position.

Fig. 11 is a wiring diagram showing the electric circuit of the hole detecting mechanism herein claimed.

Fig. 12 is an enlarged sectional View showing a modified form of double ring guides.

Referring now to the first form of this invention as shown in Figs. 1 to 5 inclusive it will be seen that a conventional revolving head circular knitting machine 10 is provided. The knitted tube [2 which is made on said machine is stationary in the sense that it does not revolve. Within said tube is a vertically extending shaft M which is connected to the revolving head of the machine and which rotates therewith on its own longitudinal axis.

Secured to shaft 14 is a bracket l6 having arms I8. It will be noted that these arms support the double ring frame 20 and the latter, in turn, carries hole-detector 22 for engagement with the knitted tube l 2. Double ring frame 20 comprises an upper ring member 2A and a lower ring member 26 which are connected at their respective end portions to blocks 28 and 30 and a pair of

rods

32 and 33 which are secured to said blocks 28 and 30 by means of set screws 34. It will be seen that these rods 32 are in spaced parallel relation to each other and that they occupy a common horizontal plane. They are slidably mounted in blocks 36 of arms l8 of the bracket and set screws 38 are provided for securing said rods to said blocks. It is by means of set screws 38 that rods 32 may be adjustably positioned on bracket I6 relative to vertical shaft I 4 and relative to the knitted tube I2. It is by this means that the double ring frame may be shifted into proper position relative to knitted tubes of various proportions. It is also by this means that the double ring frame may be made to apply greater or lesser pressure upon the knitted tube.

Ring members 2:3 and 26 may be cast integrally with blocks 28 and 30 and hence integrally with each other. If desired, they may be secured by conventional fastening means and methods to said blocks and in such case they would, of course, be separate and independent elements, either cast or machined, as desired. But whether they are cast together or fastened together ring members 24 and 26 are maintained in spaced parallel relationship and occupy spaced horizontal planes which are situated above and below the common plane which rods 32 occupy. The leading edges of the two ring members are arcuate in shape as Figs. 2 and 3 clearly show. It will be seen that the two ring members are offset from each other, the upper ring member projecting slightly beyond the lower ring member. These two ring members are offset to the same extent that the knitted tube I2 is tapered. See Fig. 1. Hence, the two ring members will exert a substantially equal force or pressure against the knitted tube.

Secured to the two ring members 24 and 26 is a vertically extending bar id which has horizontally extending arms &2 and M respectively. These arms abut the facing sides of the two'ring members and they are secured to said ring members by means of screws 46 or any other suitable fastening means. Vertical bar it is positioned centrally of the two ring members and its outer face is substantially fiush with the curved edges of said ring members. Consequently, vertical bar 4!? is inclined in the same measure that the ring members are offset and to the same extent that the knitted tube i2 tapers.

It will be seen in the drawing that the curved ed es of ring members 2 3 and 26 are normally in engagement with the inner surface of knitted tube I2 and this is also true of the vertical bar 40. The knitted fabric is held relatively taut between the two ring members so that any holes or other defects of like nature which may happen to be formed therein will very readily be detected by the hole-detecting mechanism which will hereinafter be more fully described.

Hole-detector 22 is mounted between the two ring members 24 and 26 as Fig. 4 clearly shows. The ring detector is thereby supported both on top and on the bottom and it is thereby provided with a very secure and rigid anchorage. This is extremely important for the proper functioning of the device and particularly when it reacts to the detection of a hole in the knitted fabric. More specifically, hole-detector 22 includes a casing 48 which has a top wall 58, a bottom wall 52, and one side wall 54. The other side of said casing is open. The top and bottom walls of the casing are secured to the upper and lower rin members by means of screws 56. It is this casing which supports the moving parts of the hole-detecting mechanism.

Slots 58 are formed in the top and bottom walls of the casing and it will be understood that these slots are in registration with each other and extend longitudinally of the casing. A pin 69 projects through these slots and mounted on said :aeeigsso pin, between the upperand lower walls of the casing, is a block 62. Pin 60 serves as a pivot or pintle for said block 62, enabling the block to pivot into and out of the casing. See Fig. 3. It will also :be noted that the two outwardly projecting ends of pin to are engaged by tension springs 6'4 and that the opposite ends of said springs are anchored to the top and bottom walls of the easing by means of rivets 66. These springs tend to pull pin 69 in the direction of the ring members 24 and 2E, leftwardly, as viewed in Figs. 2 and 3. The reason for this will shortly become apparent.

Block "52 has a plurality of spaced parallel holes 88 "formed therein and occupying said holes are tubular members it. These tubular members are closed at both ends, their closed forward ends being shown in Fig. 5 of the drawing. Slots 72 are provided in the front closed ends of tubes '19 and probes or feelers it are slidably mounted in said tubes with their front ends projecting through said slots. The end portions of said probes or feelers are reduced for ready penetration into any holes or similar flaws which may be encountered in the knitted fabric. Within tubes it are springs (not shown) which act upon the probes or feelers and urge them resiliently forwardly. It is these springs which maintain the probes or feelers in tensioned engagement with the knitted fabric.

It will be seen that a pair of projections or bosses T8 are provided on the forward end of block 62. It will also be seen that a pair of catch members 822 are formed at the corresponding end of casing 48. When block 62 is swung into position within casing 48, catch members as engage bosses 18 and tend to prevent said block from swinging outwardly from said casing. The bosses are held in tensioned engagement with said catch members by means of springs 54 which act upon block -52 through pin 66.

Arrow 82 in Fig. 2 indicates the direction of movement of the entire assembly mounted on shaft 14, more specifically, bracket it, double ring frame 2t and hole-detector 22. As this entire assembly revolves about the axis of shaft I4, probes or feelers ill scan the knitted tube and when a hole 234 is encountered in said tube, the probe or feeler which encounters it will enter said hole as Fig. 3 clearly shows. Since the hole is formed in a stationary tube, further movement of the assembly last mentioned will produce the eiiect also shown in Fig. 3 of block E2 swinging out of casing 18. This is the first step in the stop-motion chain of events which leads to the stopping of the knitting machine.

Secured to block 52 is a bar 86 which serves as a trigger with respect to a bumper or plunger 83. Bumper or plunger 58 is a J-shaped member having a longitudinal portion es and an arcuate end portion 52. At the proper time, that is when a hole is detected in the knitted fabric, this bumper or plunger thrusts forwardly into engagement with said fabric as Figs. 3 and 4 clearly show. The eifect of this action will shortly appear.

A block 94 is secured by means of screws 95 to casing #28 and it will be noted that said block has a channel formed therein to accommodate the longitudinal portion 96 of the bumper or plunger 88. Said longitudinal portion at is slidably movable through said channel in block 94 so that the bumper or plunger may move from its retracted position in Fig. l to its projected position in Fig. 4 and back again to its Fig. 1 position. A crossbar $3 is secured to the back end of longitudinal portion til Of the bumper or plunger and a pair of coil springs Hit are secured at one end V bracket 52b.

8 to said crossbar and at the opposite end to screws Hi2 on block M. Thus it is, that the plunger or bumper is urged by said springs to its projected position shown in Fig, 4 and when said plunger or bumper is returned to its retracted position as shown in Fig. 1, this movement takes place against the action of springs it!!! and it has the eifect-of loading said springs.

It has been said that bar '86 serves as a trigger which releases the bumper or plunger from its retracted position and enables it to move forwardly under the influence of springs [09. Bar engages a second bar I0 through a slot I06 in casing 48. Bar m4 is pivotably secured to block 94 and a leaf spring Hi8 engages said pivoted bar we to hold it in engagement with bar 86 on block 82. A plate i it is fastened to block 94 by means of screws l l2 and it will be seen that said plate secures the leaf spring N38 to said block 54 and holds said left spring in engagement with bar me.

It will be seen in Fig. 3 that a shoulder lid is provided on bar lot. When the bumper or plunger is in its retracted position, shoulder H4 engages crossbar ii and prevents the bumper or plunger from moving forwardly under the action of springs liiil. When block 62 is caused to pivot to its Fig. 3 position, when a hole or other defect of like nature is encountered in the knitted fabric, bar 8"5 cams pivoted bar Hid outwardly until crossbar 98 clears shoulder H4. The bumper or plunger is now free to thrust forwardly under the action of springs Hit to its Fig. 4 position in engagement with the knitted fabric.

When it is desired to reset the mechanism last above described, the bumper or plunger is pushed backwardly, through the knitted fabric, until its back end encounters bar 86. Further backward movement of the bumper or plunger causes block 6-2 to pivot backwardly from its Fig. 3 position to its Fig. 2 position. Not only is block 62 caused to pivot as aforementioned, but it is also caused to slide backwardly a sunicient distance to enable its bosses 8 to clear the clips Bil of the casing. At the same time, pivoted bar EM is rendered free to swing back from its Fig. 3 position to its Fig. 2 position and its shoulder H4 re-engages crossbar 98 to hold the bumper or plunger in retracted position.

It will be noted that all of the above action takes piace between the two ring members 2t and 26 of the double ring frame. All of the pivoted parts above described are provided with double bearings, that is, with a bearing support on each side thereof. Not only is this true of the pivotedparts but it is also true of the casing 53 which supports them, the upper wall of said casing being secured to ring 2 3 and the lower wall to ring 26.

Th next step in the chain of events which stops the knitting machine takes place outside of t e knitted tube. See Fig. 6. It will be noted that the bumper or plunger 88 causes a bulge i it (Fig. 4) to form in the knitted fabric, beyond vertical bar it and beyond the curved edges of ring members 2d and 28. The bumper or plunger is now in a position where it is able to encounter a pivoted arm 518 which is supported by a A set screw i221) in said bracket engages said arm H8 and it is the means by which said arm may be adjustably positioned in said bracket. Bracket $26 is adjustably secured to a shaft 22 which is rotatably supported by a second bracket iZd. Said second bracket is mounted on a frame member 126 of the knitting machine. A collar I28 above bracket I24 and a second collar :30 below said bracket are socured to shaft I22 to prevent axial shiftin or dislodgement thereof. When the bumper or plunger 88 strikes arm IIB through the bulge in the knitted tube, said arm is caused to swing from one position to another and thereby shaft I22 is also caused to turn on its longitudinal axis a corresponding angular distance.

A recess or depression I32 is formed in shaft I22 to accommodate a ball I3 2. This ball is mounted in a hole I36 formed in bracket I2 5. A compression spring I38 in said hole bears against ball I34 and holds it in tensioned engagement with shaft I22. A screw threaded plug I46 retains said spring in said hole. It will be understood that when ball I 34 is in recess I32, shaft I22 will be tensionally held in its operative position shown in Fig. 6, ready for engagement with bumper Or plunger 38. A positive force is required to dislodge said ball from said recess and thereby to free the shaft and arm I I6 for angular movement. This force is provided by the bumper or plunger. A diametrically opposite recess I22 is also provided in shaft I22 so that when said shaft and its arm I I8 are turned a full 180, ball I34 will enter said diametrically opposite recess I42 and said shaft and said arm will once again be resiliently locked in position and they will remain in such position until dislodged therefrom by a positive force. In this case, the force will be manually effected and directed and said shaft and its arm will thereby be returned to their Fig. 6 positions.

The top end of shaft I22, designated in the drawing as I22a, is reduced in size and cut down to the shape of a flat bar. Fiber insulation N14 is provided on both sides of said fiat end portion I22a to serve as electrical insulation. It will be noted in Figs. 6 and 611 that a fiber or plastic tube I26 is disposed in a vertical hole M8 in bracket I24. A rod I56 is rotatably mounted in said fiber or plastic tube and its upper end I52a s also reduced and cut away to the shape of a flat bar. A pair of brass or copper leaves I52 is secured at one end to flat portion I501]. of rod I56 and the opposite ends of said leaves abut fiber insulation I l i. When arm II8 and shaft I22 are in their Fig. 6 and 6a positions, fiber insulation M4 will prevent leaves I52 from making electrical contact with fiat end portion I22a of shaft I22.

When a defect is encountered in the knitted fabric, one of the probes or feelers will be caught in it and block 62 will be swung to one side of its casing 48. This will release bumper or plunger 88 for engagement with arm I I6 and said arm will be swung laterally out of its Figv 6 position. Flat end portion I22a will thereby be caused to engage levers I52 and an electric circuit will there by be closed in order to actuate the stop-motion mechanism of the knitting machine. The operator of the machine may now swing arm II 8 a full 180 from its Fig. 6 position until ball I3 seats itself in recess I42. This outward position of arm I I3 provides two advantages: In the first place, it serves notice of a defect in the knitted fabric which must be cleared before the machine is set back into operation. In the second place, it prevents the hole detecting mechanism from knocking-off the machine before the operator of the machine has an opportunity to clear the knitted fabric. The reason for this is plain: when arm II 3 is disposed diametrically opposite its Fig. 6 position, fiber pads I44 will prevent contact between fiattened end portion I22a of shaft I22 and contact leaves I52. When the fabric is cleared, arm H8 is returned to its Fig. 6 position and it is once again ready for engagement with bumper or plunger 88 when another defect in the fabric is detected.

Fig. 6B shows a modified form of the hole detecting mechanism last above described, the modification being principally in its switch mechanism rather than in the hole detecting mechanism. It will be noted that a block I63 of insulating material is secured to casing I6 and a leaf type of contact member I62 is secured at one end to said block. The opposite end projects forwardly of crossbar 98 and it will be noted that the intermediate portion of said leaf is bowed to avoid contact with said crossbar when the latter is in its retracted position. When a hole is detected in the knitted fabric, the process above described will take place and the bumper or plunger will be thrust forwardly against the knitted fabric. The crossbar will, of course, move together with the bumper or plunger and it will then engage the free end of leaf I62. This will close the circuit to the stop motion mechanism, thereby stopping the knitting machine.

In this form of the invention, there is no need for arm I I8 and for the switch mechanism which said arm controls. Instead, a conductor I64 is connected to contact leaf I62 and said conductor I64 projects up through the hollow shaft I66 of the knitting machine. It is then connected to the stop-motion mechanism in the usual manner. The sole difference, to the extent that concerns the present invention, between the knitting machine of Fig. 6B and the knitting machine of Fig. 1, is the difference between solid shaft I4 and hollow shaft I66. It is patently impossible to draw a wire up through the solid shaft and it is therefore necessary to provide a switch mechanism on the outside of the knitted tube. In some of the more modern knitting machines, the central shaft is hollow and it is therefore possible to connect the hole detecting mechanism to the stop motion mechanism by means of a conductor drawn through the hollow shaft. The bumper or plunger 88 is used in this form of the invention only for the purpose of resetting the hole detecting mechanism from outside the knit ted fabric. It is not used to actuate a switch mechanism located outside the knitted fabric.

Turning now to the second form of this invention and to Figs. 7, 8', 9 and 10, it will be seen that a hole detector 200 is provided on the outside of knitted tube 202. This hole detector includes a casing 264 which has a block 266 connected to its back wall. A bracket 208 projects into a hole in block 266 and supports said block and said casing. It will be noted that this hole, designated 2H1 in the drawing, extends vertically of block 266 and a vertical portion 2 I2 of bracket 268 projects into said hole. It is therefore possible to swing casing 204 about said vertical portion 2I2 of the bracket to any desired position. A set screw 2 I 4 or a pair of set screws are screwed into block 206 for engagement with said vertical portion 2I2 of the bracket to hold the casing in any desired position thereon.

Pivotally and slidably mounted in casing 204 is a block 2I6 which corresponds to block 62 of the first form of this invention. More specifically, block 2 I6 has a pair of pins 2 I 8 projecting outwardly therefrom on a common axis. These pins project through registering slots 226 which are formed in the top and bottom walls 222 of the casing. Since pins 2 I8 are mounted in slots 226 it is possible for block 2 I6 to engage both in pivotal and slidable movement in the casing. Springs 224 are provided adjacent walls 222 of the casing and oneend of said springs is secured to said walls by means of pins or rivets 226 and the opposite end of said springs is secured to pins 218. These springs are thereby enabled to act upon block 2 l 6 and to urge it forwardly in the direction of the knitted tube 262. The back wall 228 of the casing is provided at its front end with. a pair of clips 239 which project in front of block 2E6 when said block is in its retracted position in the casing. The forward end of said block is provided with a pair of bosses 232 which are engageable with clips 230 to hold the block in retracted position in the casing. Springs 224 tend to hold said block 2l6 in its forwardmost position, that is, with its bosses 232 in tensioned engagement with clips 230 of the casing. This arrangement of parts is similar to the arrangement of parts of the first form of this invention above described.

A plurality of holes 234 is formed in block 2 Hi, longitudinally thereof, and in spaced, parallel relationship to each other. Fixed in said holes are tubes 236 which are held in place therein by means of set screws 238. The forward ends of said tubes are provided with caps 24!) and said caps have slots 242 formed therein to accommodate probes or feelers 244. These probes or feelers have reduced forward ends for ready penetration into holes or other similar defects in the knitted fabric. Springs (not shown) are provided in tubes 236 for engagement with probes or feelers 244 to urge them resiliently forwardly.

It will be noted in Fig. 9 that when the probes or feelers are in scanning engagement with the outside of the knitted tube, they assume staggered or offset positions relative to each other in order to adapt themselves to the taper of the knitted tube. When a hole is encountered by any one of these probes or feelers, its reduced forward end projects into said hole as Fig. '7 clearly shows. In the knitting machine, under discussion, the knitted tube rotates and the hole detector is maintained in a stationary position. Hence, when one of the probes or feelers enters a hole in the knitted tube, and said tube rotates in the direction of arrow 246, the effect will be to swing block 2 I 6 out of its casing to its dotted line position shown in Fig. '7. When this takes place, the switch mechanism 248 on casing 204 is actuated and the knitting machine caused to stop. The switch mechanism will now be described.

A switch box 250, made of electrically non-conductive material, is secured to the outside of wall 228 of the casing by means of

screws

252 and 254. Mounted within the switch box is a pair of leaf springs 256 which are secured to a pair of bind ing posts 258. These leaf springs serve as electrical contact members with respect to a slidable contact member 260. This slidable contact member has a longitudinal portion which is slidably mounted in a channel 262 formed in wall 228 of the casing. It has a pair of sidewardly extending fingers 264 at its back end and a lug 266 at its forward end, projecting in the opposite direction from fingers 254. It will be noted that when the slidable contact member 260 moves backwardly, its fingers engage leaf springs 256, thereby closing the circuit which will hereinafter be described. Its lug 266 is engageable with the forward end of block 2H6 and when the block is in retracted position within the casing, said block prevents the slidable contact member from moving backwardly into engagement with the two 12 leaf springs 255. When block 215 is pulled outwardly from its casing to its dotted line position in Fig. '7, it disengages lug 266 and thereby frees the slidable contact member for backward movement into engagement with the leaf springs.

This backward movement of the slidable contact member takes place under the influence of a tension spring 268. The forward end of said spring is connected to the slidable contact member by means of a pin or stud 212. This stud projects through a slot 222 formed in channel portion 262 of the back wall 228 of the casing and it is movable forwardly and backwardly through said slot. The back end of the spring is secured to said back wall of the casing by means of a. pin or stud 216. Hence, when a hole is encountered in the fabric and block 296 is pulled out of engagement with lug 265, said slidable contact member is pulled backwardly into contact with the two leaf springs 256.

It will be noted that spring 268 acts against springs 22 above mentioned. Spr ngs 224 tend to urge block 2H5 forwardly and spring 268 acts to pull the slidable contact member 262, and with it said block 2V6, backwardly. The two springs 224 are, however, stronger than. spring 258 and hence they prevail as. long as block 2 it and lug 265 are in engagement with each other. When the block disengages the lug, spring 2% is free to pull the slidable contact member into engagement with leaf springs 256. It will be noted that a pair of pins 218 are fixed to the switch box 250 for engagement with leaf springs 256. These pins tend to prevent the leaf springs from engaging the slidable contact member prematurely.

The resetting mechanism for resetting both block 2 I 6 and the switch mechanism is manually operable by means of a knob 213 which is slidably movable on a bar 28!! which is secured to block 206 of the casing. A wire 282 is secured at its back end to knob 218 by means of a set screw 284. The forward end of said wire is looped around a second wire 286- which is secured to the back end of block 2H2. When knob 27B is pulled backwardly on bar 282, its wire 282 pulls upon block 2 l G and draws it backwardly into the casing. It will be understood that the backward movement of block 2H5 is from its dotted line position in Fig. 7. Since wire 2% is offset from the axial center of block 2H5, the backward pull on said block through said wire has the effect of swinging it back from its angular position indicated by the dotted lines in Fig. 7 to its longitudinally aligned position shown in Figs. 8 and 10 This brings the forward end of block 2H5 into renewed engagement with lug 265 of the slidable contact member and when the knob is released, springs 224 will return block 216 to its forwardly extending position and by the same token slidable contact member 252 will also be thrust forward until its fingers 262 are out of engagement with leaf springs 256. The circuit is now open.

A bumper is provided to prevent the knob from being pulled backwardly beyond a predetermined point. This bumper comprises a plate 238 on back wall 228 of the casing, a laterally bent end piece 299 on said plate, a dog 292 which is secured to wire 232, still another wire 2% secured to said dog and a compression spring 295 which is mounted on wire 2%. Dog 222 projects through a slot 228 in the back wall 228 of the casing and a registering slot 320 which is formed in plate 288. When knob 218 is retracted on bar 280, the ends of spring 296 are brought into abut: ment with dog 232 and end piece 290. The move- 13 ment of said dog toward said end piece will be limited by spring 296 and so will the backward movement of knob 218, wire 232 and block 2 [6.

End piece 291! and its plate 288 also perform another extremely important function. When a long run of defective material is encountered and the knitting machine is stopped as soon as the first hole is detected, it becomes necessary to run the machine until the fabric clears without interference on the part of the hole-detecting mechanism. This can be effected by simply pushing end piece 2% forwardly until the slidable contact member 260 disengages the fixed contact members 256. The machine may now be run without interruption until the fabric clears. Knob 218 may then be pulled backwardly to reset both the hole-detecting mechanism and the switch mechanism. Both will be reset simultaneously and without any danger of the operator of the machine resetting the one while forgetting to reset the other.

Fig. 11 shows an electrical diagram of the electrical system controlled by the hole-detect ing mechanism herein. described and claimed. In the diagram, reference characters 3M and 3% represent conventional stop-motion devices of a conventional circular knitting machine. The reference character 3M represents a hole-detect ing device made in accordance with this invention. It will be noted that the high side of a transformer 306 is connected by conductors 308 and 3H) to a suitable source of alternating electric current. Conductors 3l2 and 3M are connected to the low side of the transformer. It will be noted that conductor SM is connected by means of conductors 3 i t, 35 8 and 321) respectively to stop-motion devices 300 and 392 and hole-detector 304. Reference character 322 indicates the ground connection of hole-detector 3M. A sec=- ond conductor 324 is connected to hole-detector 3534 and to one side of a signal bulb 326. Another conductor 328 is connected to the opposite side of the bulb and it is also connected, together with conductor M2, to a controller 336. A slidably mounted rod 332 is controlled by said controller and said rod is connected. in conventional manner to the clutch of the knitting machine so that movement of said rod in one direction stops the machine and movement in the opposide direction frees the machine for further operation.

The controller is conventional and its rod 332 is spring-urged for movement in the direction which enables it to stop the machine. When one of the probes of hole-detector 3% is caught in a hole in the knitted fabric, one of the above described switches mechanisms (for

example switch members

256 and 260 in Figs. 9 and 10) which is connected to said hole-detector closes and grounds the unit. The circuit to the controller is thereby closed through the ground and an electro-magnet (not shown) in the controller actuates a release mechanism which releases rod 332 for spring-urged movement in the direction required for stopping the machine. A switch (not shown) in the controller is also actuated when the electro-magnet is energized and the controller circuit through the ground is thereby broken. The signal light is now energized and it flashes to call the attention of the operator of the machine to the fact that the fabric is defective and the machine is stopped.

Fig. 12 shows a variation in construction of the double ring guide which engages the knitted tube and holds it taut for the hole-detecting proce- 1d dure. The double ring guide first above described has an upper and a lower ring member which are offset from each other to conform to the curvature or taper of the knitted tube. It is possible to conform the double ring guide to the knitted tube without offsetting the two ring members from each other and this is shown in Fig. 12. It will there be seen that a double ring guide'is provided which has an upper ring member 408, a lower ring member 402, a pair of end blocks 466 to which the end of said ring members are secured and a vertical bar 404 which extends from the upper ring member 400 to the lower ring member 402 at the forward or operative edges of said ring members. These forward or operative edges register with each other since the upper and lower ring members are not offset from each other in any respect whatsoever.

Rods 4% correspond to

rods

32 and 33 of the first form of this invention. At their back ends they are supported by a bracket such as bracket I 6. At their forward ends they are provided with enlarged circular portions M0 which are provided with centered holes to accommodate bolts H2. enlargements 4W of rods 408. It is possible by loosening these bolts to swivel or pivot blocks 406 about the axis of said bolts. Since the two ring members 400 and 402 are secured to blocks 406, the effect is to cause them as well as said blocks to pivot about bolts H 2. This pivoting movement enables the double ring guide to conform to the curvature or taper of the knitted tube i2 as Fig. 12 clearly shows. In other words, the double ring guide shown in Fig. 12 is adjustable to the taper or curvature of the knitted tube, whatever that taper or curvature may be.

The foregoing is illustrative of preferred forms of this invention. It will be understood and appreciated that these preferred forms may be modified and other forms may be provided within the broad spirit of the invention and the broad scope of the claims.

I claim:

1. In a hole-detecting mechanism for detecting holes in the knitted tube which is produced on a circular knitting machine, a double guide which engages the inside of the knitted tube, said guide having an upper horizontally extending guide member and a lower horizontally extending guide member, said guide members being vertically spaced from each other and having arcuate edges which engage the knitted tube and hold that portion of the knitted tube which is disposed between said guide members taut, and a plurality of spring-urged probes which engage the taut portion of the knitted tube in the area between said guide members.

2. In a hole detecting mechanism, the combination set forth in claim 1, wherein the upper and lower guide members are oiTset from each other to correspond to the taper of the knitted tube.

3. In a hole detecting mechanism, the combination set forth in claim 1, wherein the upper and lower guide members are offset from each other to correspond to the taper of the knitted tube, a vertically extending guide bar being secured to said upper and lower guide members and being disposed at an inclined angle from the arcuate edge of the lower guide member to the arcuate edge of the upper guide member to conform to the taper of the knitted tube.

4. In a hole detecting mechanism, the combination set forth in claim 1, wherein the spring- These bolts secure blocks 406 to circularv urged probes are supported by and between the upper and lower guide members of the double:

guide.

5. In a hole detecting mechanism, the combination set forth in claim 1, wherein the double guide is adjustably positioned within the knitted tube for engagement with said tube irrespective of. the diameter of said tube.

6. In a hole detecting mechanism, the combination set forth in claim 1, wherein the double guide is mounted on the inside of the knitted tube and the spring urged probes are mounted on the outside of the knitted tube.

7. In a hole detecting mechanism, the combination set forth in claim 1, wherein the double guide and the spring-urged probes are all mounted Within the knitted tube and wherein there is relative movement between the probes and the knitted tube, a pivotally mounted block being provided for carrying said probes, said block being caused to pivot when one of said probes is caught in a hole in the knitted tube, a spring-urgedplunger supported adjacent said block for forward movement into engagement with the knitted tube in response to its spring action and for backward movement out of engagement with said knitted tube against said spring action, a catch which engages said plunger and prevents it from moving forwardly into engagement with the knitted tube and a trigger mechanism which is engageable with said catch to release the catch and thereby free the plunger for forward movement into engagement with the knitted tube in response to its spring action, said trigger being actuated by the pivotally mounted block so as to release the catch and free the plunger when the block engages in pivotal movement.

8. In a hole detecting mechanism, for circular knitting machines, a block which is pivotally mounted within the knitted tube produced on said machines, a plurality of spring-urged probes on said block, relative movement between the knitted tube and the probes being provided, said probes being maintained by said block in engagement with said knitted tube, whereby the block is caused to pivot when any one of said probes is caught in a hole in the knitted tube, a springurged plunger mounted adjacent said block for forward movement under its spring action into engagement with the knitted tube to form a bulge therein and for backward movement in opposition to its sprng action to disengage said knitted tube, a spring-urged catch which holds the plunger in retracted position out of engagement with the knitted tube, a trigger on said block which is pivotally engageable with said catch to release said catch and thereby to free the plunger for forward movement into engagement-with the knitted tube when a probe is caught in a hole in the knitted tube and the block is thereby caused to pivot, an arm pivotally mounted outside of the knitted tube for engagement with the plunger when said plunger engages the knitted tube and forms a bulge therein, a switch mechanism connected to said arm and a stop-motion device controlled by said switch mechanism, whereby engagement of the p unger with said arm causes the arm to pivot and the switch mechanism to close, thereby actuating the stop-motion device.

9. In a hole detecting mechanism, the combination of claim 8, wherein a double ring guide is mounted within the knitted tube and in engagement therewith, one of the rings of said guide being disposed above the probes and the other being disposed below the probes and supporting theblock between them for pivotal movement. relative to them, whereby the knitted tube is held in taut condition between the two rings of said guide to enable the probes to engage in smooth and precise scanning of the knitted tube.

10. In a hole detecting mechanism, the com bination of claim 8, wherein the back end of the plunger is engageable-with the trigger on the bloc-k when the block is in pivoted position and the plunger is moved backwardly, whereby the block is returned to its original non-pivoted position.

11. In a hole detecting mechanism, the combination of claim 8, wherein the switch mechanism comprises a shaft to which the arm is secured and which is rotatably mounted for rotary movement on its longitudinal axis, one end of said shaft being flattened on at least one side thereof and insulated on said flattened side, anda contact member which is mounted for engagement with said insulated, side of the shaft when said shaft is in one angular position and which is engageable with a non-insulated part of said shaft when the shaft is turned to another angular position.

12. In a hole detecting mechanism, the combination of claim 8, wherein the switch mechanism comprises a shaft to which the armis-secured and which is rotatably mounted for rotary movement on its longitudinal axis, one end ofsaid shaft be-- ing flattened on diametrically opposite sides and being insulated on said flattened sides, and a pairof contact members which are mounted for engagement with said insulated sides of the shaft when said shaft is in one angular position and,

which are engageable with non-insulated parts of said shaft when the shaft is turned to anotherangular position.

13. In a hole detecting mechanism, a switch mechanism comprising a bracket, a shaft mounted. in said bracket for rotary movement on its longitudinal axis, an arm secured to said shaft and.

extending laterally thereof to control the angular position of said shaft in said bracket, one of the ends of said shaft being flattened and insulated. on both sides, and a pair of spring contact mem-- bers which are supported at one end by said bracket and which are insulated from said bracket, the opposite ends of said spring contact, members being engageable with the insulated sides of the shaft when the shaft is in one angular position in said bracket and also when the shaft is in another angular position in said bracket,

removed from the first position, and which are engageable with non-insulated parts of the shaft, when the shaft is turned to any other angular position.

14. In a hole detecting mechanism, the-combination of claim 13, wherein the shaft is provided with a pair of recesses formed therein on diametrically opposite sides, a spring-urged ball being mounted within the bracket for engagement with said recesses to resiliently hold the shaft in the first mentioned position and in the position which is 180 removed therefrom.

References Cited in the file. of this patent UNITED STATES PATENTS- Number Name Date 1,081,410 shimer Dec. 16, 1913 2,259,607 Berthold' Oct. 21, 1941 2,570,995 Vossen Oct. 9, 1951 2,571,211 Crawford Oct. 16, 1951