US3527065A

US3527065A - Fabric controlling means for circular knitting machines

Info

Publication number: US3527065A
Application number: US698094A
Authority: US
Inventors: Roland Peberdy
Original assignee: Bentley Engineering Co Ltd
Current assignee: Bentley Engineering Co Ltd
Priority date: 1967-01-13
Filing date: 1968-01-08
Publication date: 1970-09-08
Anticipated expiration: 1987-09-08
Also published as: DE1635752A1; GB1215448A; FR1561252A; DE1635752B2

Description

R." IPYEIEBYE'RDY Sept; 8, 1970 V 1 FABRIC CONTROLLING MEANS FOR CIRCULAR KNITTING MACHINES Filed Jan. 8, 1968 4 Sheets-Sheet l Sept 8,191 0 V I R.FIEYBEIDY -3,527, 065

FABRIC CONTROLLING MEANS FOR CIRCULAR KNITTING MACHINES Fiid Jim." 8, 1968 4 Sheets-Sheet 2 R. PVEBERDY i-FABRIC CONTROLLING MEANS FOR CIRCULAR KNITTING MACHINES iled Jan. 8, 1968 4 Sheets-Sheet 5 Qv-m oomm R. PEBERDY Sept; 8, 1910 FABRIC CONTROLLING'MEANS FOR CIRCULAR KNITTING MACHINES Filed Ja 8, 1968 r 4 Sheets-Sheet 4.

now l United States Patent Int. Cl. D041) /88 US. Cl. 66-14 4 Claims ABSTRACT OF THE DISCLOSURE 7 Fabric draw-off means in a circular knitting machine comprising fabric loop engaging instruments spaced apart around the circle of needles in a needle cylinder and mounted to operate in the neighbourhood of the needle circle at positions related to needle positions, such instruments being cam actuated in turn at a knitting station so that fabric loop engaging feet on them are moved first upwardly and outwardly to near the needle circle and then downwardly and inwardly to draw off fabric. The loop engaging instruments may be rocking instruments accommodated in internal tricks in a cylinder opposed to the needle cylinder and operated by appropriately timed raising and lowering cams and rocking cams.

This invention is for improvements in fabric controlling means for circular knitting machines and is concerned more particularly with the control of fabric as it is being formed and drawn inwards of the needle circle. It is an object of the invention to provide means capable of operating with precision to assist in the formation of fabric from the time such fabric is first set up on the needles.

In accordance with the invention there is provided fabric controlling means comprising fabric and/or loopengaging instruments spaced apart around, and in the neighbourhood of, the needle circle at positions related to positions of needles, mounting means for said instruments on which the instruments are mounted to direct them towards the needle circle, and means for operating the instruments to move their fabric and/0r loop-engaging portions sequentially each in a closed path with components of movement to and fro both in the radial and axial directions relatively to the needle cylinder and at the appropriate times to draw loops of freshly formed fabric inwardly from the needles. By this provision fabric can be urged away from the needles (as is required to perform the knitting action) from approximately the time the fabric is set up on the needles because the said instruments can engage loops of the fabric in the vicinity of the needles, and by continuing to do so during the formation of the fabric the said instruments assist in maintaining performance of the correct knitting action.

It is desired to provide a sufficient number of the said instruments uniformly spaced apart around the needle circle to ensure that all parts of the fabric around the needle circle have the requisite inward urge applied to them. To this end the said instruments may be equal in number to the number of sinkers or needles so that at least one of said instruments is associated with each needle position. A smaller number of such instruments may, however, be found satisfactory in some circumstances.

The mounting means for the aforesaid instruments is conveniently an opposed cylinder member mounted coaxially with the needle cylinder and having tricks formed in it to accommodate the stems of the said instruments. These may be formed as rocking instruments (similar to 3,527,065 Patented Sept. 8, 1970 known rocking selecting instruments employed in some circular machines) and they may be actuated by cams to eifect endwise sliding movement of the instruments and a cam to effect rocking of the instruments in their tricks. The cylinder for mounting the instruments is itself mounted so as to be in a fixed setting in relation to the needle cylinder. In the case of a rotary needle cylinder machine the cylinder forming the mounting for the tension applying instruments will rotate with the needle cylinder.

The invention may be applied to a circular knitting machine having co-axial opposed needle cylinders and equipped with double ended needles and sliders whereby such needles may be operated in either cylinder, in which case the cylinder for mounting the instruments is conveniently positioned within one of the needle cylinders and secured thereto and may have the instrument receiving tricks formed internally in it. When the invention is applied to a double cylinder machine having verge bits fitted to the upper cylinder, the instruments for urging fabric away from the needles may be mounted within the upper cylinder and conveniently also inwardly of the verge bits. As will appear later the invention can also be practised conveniently in connection with a single cylinder circular knitting machine.

Certain specific examples of applications of the invention to several different types of circular knitting machines are illustrated in the accompanying drawings and will now be described with reference to the drawings, in which- FIG. 1 is an elevation view in central cross-section taken through the adjacent ends only of the needle cylinders and showing only those parts necessary for an understanding of the invention,

FIG. 2 is a developed view of three cam rings shown in FIG. 1, as viewed from the inside of the rings, but with one ring (the bottom one) shown in plan view so that its form may be seen in relation to the two upper cams,

FIG. 3 is a view corresponding to a portion of FIG. 1 showing a modification in which the invention is applied to an opposed co-axial needle cylinder machine having verge bits operated in one manner;

FIG. 4 is a view corresponding to FIG. 3 but showing the invention applied to a machine having verge bits operated in a different manner, and

FIG. 5 shows another modification in which the invention is applied to a single cylinder machine having outside sinkers.

In FIG. 1, the upper needle cylinder is shown at 1 and the lower needle cylinder at 2. The cylinders have tricks 1a and 2a, provided to accommodate needles 3 and sliders 4. Located within the cylinder 2 is a sinker ring 5 carrying sinkers 6, the operating butts 6a of which co-operate with upper and

lower cams

7 and 8 in conventional fashion.

Cams

7 and 8 are secured to the sinker cup 9, which is maintained stationary while the sinkers and needle cylinders revolve around it. Thus the hooks of the sinkers 6 are given radial in and out motions by the action of their butts 6a in the track formed between the

cams

7 and 8.

Housed within the upper cylinder 1 adjacent to its lower end is a mechanism used in carrying out this invention. A short mounting cylinder 10 is located within the cylinder 1 and secured to it by screws such as 11. Spaced apart around the inside of cylinder 10 vertical slots or tricks 12 are cut to provide slide-ways for fabric and/or loop-engaging instruments 13. The instruments 13 are, in the example shown, equal in number to the spaces between needles in the needle circle. They are positioned above and in line with the sinkers so that between each two adjacent needles there is located in sinker 6 an instrument 13.

As can be seen in FIG. 1 each of the instruments 13 has a projecting butt 1311 which is guided in the track formed between the cams l4 and 15 to cause up and down movement of the instruments as they revolve around the cams. The track between

cams

14 and 15 can be seen in developed view, FIG. 2. In addition to vertical motion, each of the instruments is also capable of a radial rocking action, using a point opposite to and level with the butt 13a as a pivot point. The instrument shown on the right hand of FIG. 1 is in the inwardly rocked attitude and also the raised position, while the instrument shown on the left of FIG. 1 is in the outward and lowered position. The rocking action is obtained from the bottom cam 16, the outer edge of which is shaped in the manner shown in the developed view, FIG. 2, in which cam 16 is shown in plan view. A band spring 21 which encircles the instruments 13 maintains them in contact with the profile of cam 16 and is located vertically by a projection 13b positioned just above the foot of each instrument.

The tube 20 is mounted on a stationary central rod or stem 39 which projects below the tube 20 and hub ring 17 to carry a spacing sleeve 40 and a disc 41 forming a mounting for a fabric guide 42 which deflects downwardly fabric fed inwards by the instruments 13. The lat ter is in the form of a plate shaped to curved conical form and held in place against the underside of the disc 41 by a central long bolt 43 screwing into the bottom end of the rod or stem 39.

The mechanism functions in the following manner.

As the needle cylinders rotate, the butts 13a of the fabric and/ or loop-engaging instruments follow the track between

cams

14 and 15 in the direction of the arrow ED (FIG. 2). The majority of the track maintains the instruments 13 in the low position wherein serrations cut in the feet of the instruments are approximately level with the top of the sinker ring 5 which is built up cally at 5a to form a ledge against which the fabric or fabric loops will rest when engaged by the feed of the instruments 13. This built up surface contains radial slots which are automatically provided by the saw used to cut the arcuate slots for the sinkers 6. The slots in the built up surface 5a are directly below each instrument and therefore, when fabric is being produced and is being cast off inwards of the needles, the instruments will engage the fabric and resiliently depress it into the radial slots which are opened out slightly to form fabric receiving channels.

The instruments maintain their contact with the fabric for the majority of the time taken to complete one revolution of the needle cylinders. However, at each stitch making zone (and two such zones are shown at A and B in FIG. 2) the instruments 13 are first raised serially by the cam slope a to disengage them one after another from the fabric and then they are moved outwards by the slope 16a of the bottom cam 16. They then contact slope 14a of the top cam and are brought down into contact with the fabric just behind the needles and upon reaching the inward slope 16R of the bottom cam are urged inwards, resiliently and in engagement with the fabric, by the band spring 21.

The inward urging action of the instruments 13 is timed to commence approximately when the needles are moving down the stitch drawing cam and the old loops are being cast off over the heads of the needles. The instruments, therefore, provide an additional controlling means, functioning in co-operation with the needles and sinkers to complete the loop forming and casting oif process, and by a continuance of their action to urge the knitted fabric away from the needles, all in a manner which has heretofore not been accomplished in any such precise manner.

The timing of the movements of the instruments 13 in relation to the sinker movements is shown in FIG. 2 a development lay out of the sinker cam track between

cams

7 and 8 being shown at the bottom of the figure as viewed looking outwardly from within the cylinder 2. It will be seen that in the region of knitting zone A the sinker cam track indicated at 44 diverts upwardly at to move the sinkers outwards well in advance of the cam slopes 15a and 16a which cause the instruments 13 to be moved upwardly and then outwardly. The sinkers are moved further outwardly at the track portion 46 also in advance of the slopes 15a and 16a and afterwards are moved inwardly in two stages by the

track portions

47 and 48 the first of which corresponds in position to the inward slope 16R of cam 16 and the second of which, controlling the main return sinker movement is delayed to somewhat later after the instruments 13 have commenced their inward movements under the action of spring 21. Similarly at knitting zone B track portion 49 moves the sinkers outwards simultaneously with the action of cam slope 15a and slightly in advance of that of cam slope 16a. Also return track slopes and 51 are timed similarly to

track slopes

47 and 48.

FIG. 3 illustrates the application of the invention to an opposed co-axial cylinder maching having the upper cylinder equipped with verge bits (providing rib loop draw edges) which are capable of vertical movement en bloc. The bottom cylinder and its associated parts are constructed exactly as shown in FIG. 1 and bear the same reference numerals. Such parts are: bottom cylinder 2 having needle tricks 2a, sinker ring 5 having built up shelf portion 5a, sinkers 6,

sinker cams

7 and 8 and sinker cup 9. The upper needle cylinder is shown at 21 and it has external needle tricks 21a and formed internally in it are tricks 21]; for verge instruments 22. The latter have butts 22a which fit in a circumferential groove 23b in a cylinder 23 formed internally with tricks 23a. In the tricks 2311 there are contained rocking instruments 24 corresponding to the instruments 13 of FIG. 1 having butts 25 engaging between upper and lower cams 26 and 27 which correspond to the

cams

14 and 15 of FIG. 1. Also acting on the instruments 24 is a cam 28, which corresponds to the cam 16 of FIG. 1, and a band spring 128 positioned below cylinder 23 for urging the instruments 24 into engagement with cam 28.

The cylinder 23 is mounted to rotate with the upper needle cylinder 21 but to be slidable vertically to a limited extent in relation thereto in order to raise and lower all of the verge bits 22 en bloc. To this end the cylinder 23 is clamped to a ring 29 at angularly spaced intervals by means of bolts 30 which also hold dogs 31 arranged to engage in slots between splines 32 formed internally on the upper part of cylinder 21. The ring 29 is rotatably carried on a central fixed stem or rod 33 by being fitted together with an anti-friction supporting thrust bearing 34 between abutment rings 35 and 36 mounted on a sleeve 37 which is slidable vertically on the stem or rod 33, but prevented by a key 52 from rotating thereon. The stem or rod 33 also forms the support for a stationary hub ring 38 corresponding to the part 17 of FIG. 1, on which the cams 26 and 27 are mounted in the same manner as are the

cams

14 and 15 of FIG. 1.

By raising and lowering the sleeve 37 in known manner by instrumentalities operated from a main control drum, the cylinder 23 is raised and lowered to raise and lower the verge bits 22 at required times. At the lower end of the stem or rod 33 there is mounted a disc 53 forming a mounting for a fabric guide plate 54 held in place by a long bolt 55 as in the construction of FIG. 1.

In the modified construction of FIG. 4 the invention is shown applied to a machine having individual movable verge bits which are indicated at 56. In this case as before the bottom cylinder is indicated at 2, its tricks at 2a, a sinker ring at 5, sinker cams at 7 and 8, and sinkers at 6. The

cams

7 and 8 are carried by a sinker cup 57 of somewhat modified form compared with the sinker cup 9. The sinker ring 5 has a somewhat modified enlarged step portion indicated at 5b presenting a downwardly and inwardly sloping surface. The top needle cylinder is indicated at 58 and its tricks at 58a which receive the needle sliders. The cylinder 58 has fitted internally to it a lining cylinder 59 which is formed internally with deep tricks 59a in which are slidable the stem parts 56a of the verge bits 56. The stems 56a in their main portions are much shallower than the tricks 59a so as to allow room in the tricks 59a for the stem parts of fabric and/or loop engaging instruments '60 which can slide in the tricks in edge to edge relationship to the stem parts 561:. The internal cylinder 59 is fixed to the cylinder 58 by engaging partly around a circular rib 61 formed internally on cylinder 58 and being clamped to such rib by means of a clamping ring 62 and clamping screws '63 positioned at intervals around the ring 62.

The verge bits 56 have upstanding guiding spurs 56b which ride in vertical slots 64 formed internally in the lower part of the cylinder 58. They also have enlarged parts 56c at the upper ends of their stems 56a formed of the full depth of the tricks 59a and carrying operating butts '65 which are engaged between upper and lower cam plates 66 and 67 mounted externally on a central non rotary cam supporting ring '68. This is secured by a grub screw 69 to a sleeve 70 which is slidable vertically on a fixed stem or rod 71 corresponding to the stem or rod 33. The sleeve 70 is permitted limited up and down movement on the stem or rod 71 but prevented from turning thereon by means of a key 72. The sleeve 70 may be controlled for up and down movement in the same manner as sleeve 37. Thus the cams 66 and :67 which remain still whilst the cylinders '58 and 59 rotate to carry with them the verge bits 56, serve by engagement the butts '65 to provide for individual up and down movement of the verge bits 56 in a required manner, whilst the mount ing of cam ring 68 on the sleeve 70 enables the whole of the verge bits 56 to be moved en bloc up and down at appropriate times under the control of the main control drum.

The instruments :60 are movable up and down in the tricks 59a independently of movements of the verge bits 56 and they are also capable of rocking in the tricks about a fulcrum point against the stems 56a of the verge bits such fulcrum point being located near the upper part of the stems of the instruments 60 immediately, alongside an operating butt 73 on each instrument 60. The instruments 60 like those indicated at 24 in FIG. 3 are operated by engagement of their butts 73 between upper and lower cams 74 and 75. These correspond to the cams 26 and 27 of FIG. 3 and present between them a similarly shaped cam track which corresponds to the track between

cams

14 and 15 shown in FIG. 2. The cams 74 and -75 are fixed to a cam ring 76 which has an offset collar in which is screwed a grub screw 77. The cam ring 76 fits directly on to the stem or rod 71 and the grub screw 77 serves to secure the cam ring in fixed position on the stem or rod 71. The cam ring 76 has a central recess in which is located a compression spring 78 acting upwardly on the sleeve 70 and parts carried thereby to assist in raising the cam ring 68 when the verge bits '56 are required to be withdrawn. The spring 78 corresponds in function to a similar spring 79 in the construction of FIG. 3.

Rocking of the instrument 60 is controlled by a cam 80 which corresponds in its cam outline to the cams 16 and 28 of FIGS. 1 and 3. The instruments 60 are yieldably held by a band spring 81 in engagement with the periphery of cam 80 the latter being fixed by screws, one being shown at 82, to a disc 83 fitted on the bottom end of the stem or rod 71 and secured thereto by a grub screw 84. The disc 83 has its under face 85 formed of conical shape to form a fabric deflecting guide corresponding in function to the plates 42 and 54 previously described.

FIG. shows the application of the invention to a single cylinder circular knitting machine. The machine has a rotary needle cylinder which is indicated at 86 and has tricks 86a in which are slidable the stems of needles 87 having operating butts 88. Fixed to the upper end of the cylinder 86 so as to rotate therewith there are an internal sinker guide ring 89 and an external sinker ring 90 formed with tricks in which outside sinkers 91 are mounted for movement radially of the cylinder. The sinker guide ring 89 presents a built up surface 92 similar to and having the same function as the surface 5a in FIG. 1. Extending around and partly overlying the sinker ring 90 there is a stationary sinker cam ring indicated somewhat diagrammatically at 93 presenting a cam track 94 in which butts 95 on the sinkers 91 run in known manner. Inside the cylinder 86 there is a throated fabric receiving tube 96.

Above the cylinder 86 in vertical alignment therewith is an instrmnent-supporting cylinder 97 which is driven to rotate at the same speed as and in registry with the cylinder 86. In tricks 97a of cylinder 97 there are mounted fabric and/or loop engaging instruments 98 equal in number to the needles 87 in cylinder 86 and positioned between the needles so as to be approximately in line with the sinkers 91. The instruments 98 have operating butts 99 and also fulcrum points approximately level with these butts about which they can rock against the backs of the tricks 97a. In addition the instruments 98 have outward projections 100 accommodated in a recess 101 formed internally in the bottom of the cylinder 97. Between the projections 100 and the feed of the instruments 98 there is a band spring 102 encircling the instruments and corresponding in function to spring 21 of FIG. 1. The cylinder 97 is fixed at intervals by screws 103 to an upper ring 104 rotatably mounted on a fixed vertical spindle 105 and supported thereon by an anti-friction thrust bearing 106. The spindle 105 is secured by a mounting plate 107 and screws 108 to an arm 109 which can swing about a horizontal laterally offset axis for the purpose of raising and lowering the spindle 105 and the parts carried thereby. Mounted in bearings in the arm 109 there is a horizontal driving shaft 110 for driving the cylinder 97 in step with the needle cylinder 86, through a bevel gear 111 on shaft 110 meshing with a bevel gear 112 formed on or attached to the ring 104.

To the lower end of spindle 105 there is secured to it by means of a mounting plate 113 and screws 114 a cam supporting ring 115 which is restrained by a key 116 against turning on the spindle. Fixed to the cam supporting ring 115 by upper and lower sets of screws 117 there are upper and lower cam rings 118 and 119 and the lower screws also fix in place a bottom cam ring 120. The cam rings 118 and 119 correspond to the cam rings 14 and 15 of FIG. 1 and present between them a trackway like that shown in developed view in FIG. 2, in which trackway the butts 99 will run as cylinder 97 rotates. The bottom cam ring 120 corresponds to cam ring 16 of FIG. 1 and has a contour as shown for ring 16 in developed view in FIG. 2.

In the constructions of FIGS. 3, 4 and 5 the fabric and/or

loop engaging instruments

24, 60 and 98 are operated in the same manner and with substantially the same timing as are the instruments 13 of FIG. 1. However, because of the provision of' the verge bits 22 and 56 the instruments 24 and 60, in the constructions of FIGS. 3 and 4, may need to engage the fabric at positions slightly further from the needles than do the

instruments

13 and 98 of FIGS. 1 and 5. Should this be found to be disadvantageous the instruments 24 and 60 may be set sufficiently out of register with the respective verge bits 22 and 56 to enable them to operate alongside the verge bits in the spaces between needles. This may be effected in the FIG. 3 construction by slightly adjusting the angular setting of cylinder 23 in relation to cylinder 21, and in the FIG. 4 construction by making the stems of the instruments 60 and the verge bits 56 of the same width equal to the full depth of the tricks 59a (or somewhat shallower tricks) and fitting them one of each side by side in each of the cylinder tricks each of which would be made wider to receive the two stems.

An alternative way of avoiding difficulties due to the 7 presence of verge bits in an opposed needle cylinder machine, would be to practise the method of knitting in which rib stitches are drawn across the undersides of the sinker nibs, thereby avoiding the need for verge bits and enabling the construction of FIG. 1 to be used.

It may be found advantageous in some circumstances to position the fabric and/or loop-engaging instruments slightly to one side of the sinkers to avoid possible interference therewith or with sinker bluffs, or even to position the said instruments behind the needles. This can be achieved by appropriate angular adjustment, in the manner above-mentioned, of any of the

cylinders

10, 23, 59 and 97 in relation to the respective needle cylinders, any consequential modification of the in and out stroke of the

instruments

13, 24, 60 and 98 that may be needed being provided for by substituting a modified edge cam in place of the appropriate cam 16, 28, 80 or 120.

What I claim is:

1. In a circular knitting machine the combination comprising a circular knitting bed, needles mounted in said bed in circular arrangement, fabric loop engaging instruments spaced apart around and in the neighborhood of the needle circle at positions related to positions of the needles, mounting means carrying said instruments in positions directed towards the needle circle, means for operating the instruments to move their fabric loop engaging portions sequentially each in a closed path with components of movement to and fro both in the radial and axial directions relatively to the needle circle at appropriate times to draw loops of freshly drawn fabric inwardly from the needles, opposed co-axial needle cylinders one of which provides the said circular needle bed, means mounting said cylinders on the machine, the said needles constituted by double ended needles and sliders provided to support said needles in either cylinder, the mounting means for the said fabric loop engaging instruments being constituted by an internal cylinder positioned within the other of said needle cylinders and secured thereto and formed internally with instrument-receiving tricks to accommodate the fabric loop engaging instruments, and including means for rotating the opposed needle cylinders in step with one another, a central stationary stem portion projecting through the said other needle cylinder, a cam ring mounted on said stem and positioned within said other needle cylinder and earns extending around said cam ring for operating the fabric loop engaging instruments for to and fro movement longitudinally of the needle cylinders and having fabric engaging instruments formed as rocking instruments and a further cam provided on the cam ring for rocking the said instruments in the tricks of the said internal cylinder.

2. A machine according to claim 1 having mounted on the appropriate end of the said stem a fabric guide positioned to reach into the mouth of the cylinder opposite to that through which the stem projects to deflect outwardly fabric fed inwardly by the fabric loop engaging instruments.

3. In a circular knitting machine the combination comprising a circular needle bed, needles mounted in said bed in circular arrangement, fabric loop engaging instruments spaced apart around and in the neighborhood of the needle circle at positions related to positions of the needles, mounting means carrying said instruments in positions directed towards the needle circle, means for operating the instruments to move their fabric loop engaging portions sequentially each in a closed path with components of movement to and fro both in the radial and axial directions relatively to the needle circle at appropriate times to draw loops of freshly drawn fabric inwardly from the needles, opposed co-axial cylinders, the bottom one of said cylinders being a needle cylinder which provides the said circular needle bed, means for mounting said cylinders on the machine, the upper cylinder being a mounting means for slidably mounting the said fabric loop engaging instruments therein, the said upper cylinder being formed internally with instrument-receiving tricks to accommodate the fabric loop engaging instruments, the fabric loop engaging instruments having operative parts positioned closely adjacent to and within the needle circle, and means for rotating the opposed cylinders in step with one another, a central stationary stem portion projecting through the said upper cylinder, a cam ring mounted on said stem and positioned within said upper cylinder and cams extending around said cam ring for operating the fabric loop engaging instruments for to and fro movement longitudinally of the upper cylinders and having fabric engaging instruments formed as rocking instruments and a further cam provided on the cam ring for rocking the said instruments in the tricks of the said upper cylinder.

4. A machine according to claim 3 having mounted on the appropriate end of the said stem a fabric guide positioned to reach into the mouth of the cylinder opposite to that through which the stern projects to deflect outwardly fabric fed inwardly by the fabric loop engaging instruments.

References Cited UNITED STATES PATENTS 331,400 12/1885 Huse 66-90 901,839 10/1908 Scott 66-107 XR 925,036 6/1909 Scott 66-107 1,641,101 8/1927 Scott 66-149 XR 1,881,360 10/1932 Kent 66-90 XR 2,463,258 3/1949 Fuller 66-107 3,003,342 10/1961 Kent et a1. 66-150 3,283,539 11/1966 Peberdy 66-14 3,292,394 12/1966 Luchi 66-149 3,417,581 12/1968 Docekal et al 66-147 FOREIGN PATENTS 878,161 9/1942 France. 432,233 7/1935 Great Britain.

0 WILLIAM CARTER REYNOLDS, Primary Examiner U.S. Cl. X.R. 66-90, 107, 147