US2629994A - Straight bar knitting machine - Google Patents

Description

March 3, 1953 A. P. SAUNDERS 2,629,994

STRAIGHT BAR KNITTING MACHINE Filed Sept. 2. 1950 6 Sheets-Sheet l Inventor March 3, 1953 Filegi Sept. 2. 1950 A. P. SAUNDERS STRAIGHT BAR KNITTING MACHINE Fla #2 6 Sheets-Sheet 2 Inuenior i March 3, 1953 I A, SAUNDERS 2,629,994

STRAIGHT BAR KNITTING MACHINE Filed Sept. 2. 1950 6 Sheets-Sheet 3 Inventor Mm u March 3, 1953 A. P. SAUNDERS 2,629,994

STRAIGHT BAR KNITTING MACHINE Filed Sept. 2. 1950 e Sheets-Sheet 4 Inventor mm /2 WW March 3, 1953 A. P. SAUNDERS 2,629,994

STRAIGHT BAR KNITTING MACHINE Filed Sept. 2. 1950 6 Sheets-Sheet 5 Inventor 40/70 I, JWIVMIJ yg i March 3, 1953 A. P. SAUNDERS 2,629,994

STRAIGHT BAR KNITTING MACHINE Filed Sept. 2, 1950 6 Sheets-Sheet 6 Inventor Patented Mar. 3, 1953 STRAIGHT BAR KNITTING MACHINE Alfred Percy Saunders, Leicester, England, assignor to Wildt and Company Limited, Leicester, England, a British company Application September 2, 1950, Serial No. 183,020 In Great Britain September 5, 1949 12 Claims.

This invention relates to straight bar knitting machines, and has reference particularly to mechanism incorporated in such a machine for efiecting and controlling movements of a member or members in opposite directions in suitable timed relation with the operation of the machine, for any appropriate purpose.

Broadly speaking, the invention is concerned with any such mechanism of the class comprising a threaded member or members engaged with a threaded portion or portions of a rotary screw, and controlled means for driving the said screw in an appropriate manner in either a clockwise or an anti-clockwise direction, according to requirements.

In this connection it is principally the intention to apply the invention to a mechanismof the kind comprising a pair of threaded members respectively engaged with right-hand and lefthand threaded portions of a rotary screw, although the invention is not necessarily limited in this respect as it may also be applied to a mechanism including but a single threaded member movable axially in opposite directions upon a correspondingly single threaded portion of a rotary screw.

The invention, moreover, is primarily concerned with the pivoted fashioning head of a straight bar knitting machine which head, as well known to those acquainted with theart concerned, comprises right-hand and left-hand groups of transfer points adapted for use in the transference of knitted loops from appropriate needles to adjoining needles in the shaping of garments, e. g. hose blanks. In such a head the said groups of transfer points are associated with threaded carriers respectively engaged with righthand and left-hand threaded portions of a screw which is adapted to be racked round in either direction, by pawl and ratchet gearing controlled by or from the timing or controlling means of the machine, for the purpose of traversing the groups of transfer points laterally towards or away from each other, according to requirements. These lateral movements of the groups of transfer points are efiected in timed relation with up and down movements of the pivoted fashioning head, the sequence of operation bein such that the points move first down to receive knitted loops from appropriate needles, then up again whereupon they are racked laterally in either direction, say to the extent of one or-two needle spaces, preparatory to moving down again to replace the knitted loops on adjoining needles.

The threaded members in a mechanism of the particular kind herein referred to may, in a further application of the invention, constitute or serveto control stops for determining the variable extents to which yarn carriers are traversible.

Accordingly, the term threaded members used in this specification and in the appended claims is sufficiently broad to cover not only transfer point carriers and stops or stop controlling means, but also any other appropriate parts in a straight bar knitting machine which require to be moved towards and away from each other consequent upon the turning ofa screw, whether the screw moves with the pivoted narrowing head or is mounted in stationary bearings.

It is desirable to incorporate in a mechanism of the class concerned means for limiting the extents of the movements of the threaded member or members in both directions, since other- Wise there would be a risk of breakage and other damage to the machine in the event of the latter being or becoming incorrectly timed.

For instance, in the absence of any limiting means, incorrect timing of a straight bar knitting machine would result in the groups of trans fer points travelling beyond their normally safe positions. The provision of limiting means, moreover, definitely restricts the width between the groups of transfer points to the extent of a predetermined number of needles, even in the event or the means for racking the transfer point carriers making more racks than necessary, thereby ensuring that the terminal ends of the garments or blanks produced are of uniform width when pressed oil.

The primary object of the present invention, then, is to provide improved means of a particularly simple, efficient and compact character for positively limiting the extents of the move-- ments OI the aforesaid threaded member or members. In this connection the principal aim is the incorporation, in the pivoted fashioning head of a straight bar knitting machine, of means, arranged remotely from the rotary screw, for automatlcally determining in a positive manner, and without any direct contact with the threaded members, the safe limits of the inward and outward lateral movements of the two groups of transfer points.

Another ob ect of the invention is to provide, in a straight bar knitting machine, an improved arrangement of the pawl and ratchet gearing for racking the transfer point carriers of 1a pivoted fashioning head as will be hereinafter described.

According to this invention the rotary screw of a mechanism of the class concerned is driven by means capable of being so influenced as to effect interruption of the drive in either direction and thereby arrest the movement of the threaded member or members, and there is provided in association with the driving means a trip or stopmechanism including. a component movable between limits in timed relation with the movements of the rotary screw, the said component being adapted, when moved to the limit in one direction or the other, dependingon the direction, or the respective directions, of

movement of the threaded member or members,

to influence the driving means for the purpose aforesaid.

For the sake of convenience the said com- 7 ponent which is movable between limits will be referred to as the trip or stop component.

Moreover, also for the sake of convenience in the following further descripton, the invention" will be described as applied to a mechanismof the kind herein referred to, i. e. wherein a pair of threaded members are respectively engaged with right-hand and left-hand threadedportions of arotary screw, without, however, limitation in this respect. Thus, as will be appreciated, whenever such threaded members are moved. inwards towards each other the trip or stop component will be moved in one direction towards one limit and'whenever the said membersv are moved-outwards" away from each other the trip e! stop component will be moved in the opposite direction towards the other limit.

The idea-is-that during normal working of a straight bar knitting machineto which the invention is applied, the trip or stop mechanism shall remain inactive, thetrip or stop componentmerely moving idly. back and forth between the two limits'in-sympathy with the movementsoftherthreaded members, butthat when, for instance as a consequence of the machine being out oftime, the said component is moved to: the limit in either direction, the trip or stop mechanism; shall then function automatically to stop the rotary screw. In this way the threaded members engaged with the rotary screw will positively be prevented from moving towardsor away from each other beyond predetermined safe limits. In short, the trip or stop mechanism functions only in an emergency.

According to a further improvement provided by. this. inventionthe pawl and ratchet gearing customarily provided for racking. the screw in the pivoted fashioning head of a straight bar knitting machine is mount'ed'entirely on the said head; the construction and arrangement being, however, such that the racking takes place independently of the pivotal movements of the head.

A specific constructional example of the invention as applied to" the fashioninghead of a straight barknitting machine will now be' described with reference to the accompanying drawings, wherein,

Figure l is afragmental detail view partly in section-of the elements shown in the lower portionof'Figure 3.

Figure lA-is afront view, partly in section, of so much of the said fashioning headand adjoining parts-of the straight bar knitting machine as arenecessaryto an understanding of the invention,

Figure. Zis a detail part-sectional. end view, taken onthe line. II -II of FigurezlA showing 4 an indexing or check wheel on th drive shaft to which the rotary screw is geared,

Figure 3 is, in part, a vertical sectional view taken on the line IIIIII of Figure 1A depicting the trip or stop component in relation to the blufiing members controlled thereby, and showing also the means for timing or: controlling the racking of the rotary screw,

Figure 4 is an end elevational view of bluffs and control means therefor for determining the direction and extent of racking of the screw,

Figure 4A is an end elevational view of the bluffs: andicontrol means which are joined to the end of the slideshown in Figure 4.

Figures 5 andG' are two detail views illustrating these bluffs and control means in respectively different positions hereinafter to be described, and

Figure '7 is a detail part-sectional elevation of the control drum of the machine and associated connections for initiating movement'of the controlmeans illustrated in Figure 3.

Like parts are designated by similar reference characters throughout the drawings.

Referring to Figure 1A, it will be seenthat the machine is provided with a pivoted fashioning (or narrowing) head the frame of which comprises two spacedcarrier arms I fulcrummed to turn about the aXis a and connected. by a longitudinally extending. shaft 2. Onthis shaft are secured appropriately spaced brackets 3, 4 and 5 having therein bearings for a rotary screw; 6. The screw has a comparatively coarsepitched right-hand threaded: portion 6a anda similarly pitched left-hand portion 61) with which portions are respectively engaged. two complementarily threaded carriers 7 and 8 suitably formed for en.- gagement slidably with: guide. bars 9 and. I0 and serving to carry right-hand and left-handgroups of transfer points. I I and I2, The. transfer points are adapted for use, as previously ex:- p1ained-,in the transference of knitted loops-from appropriate ones: of the: needles, indicated diagrammatically at l"3 in Figure lA,.to adjoining needles in the shaping; of garment. blanks.-- The sinkers and dividers of the machineare indi cated at M, and the knock-over hits at l5 l6 represents a'yarn-carrier. The right-hand end ofthe rotary screw 6 (as viewed from the front of the knitting machine) extends through the bracket 5 and is fittedwith a spur pinion I1 arranged in. mesh, as shown more clearly in Fig:-v ure 2,.witha spur gear IBsecured to an off-setrack shaft (1; e. drive shaft). l9. which is? disposedv parallel to. the screw 6.- The; pinion I! is secured upon a reduced end of the screw 6 -by means of a nut 20. The inner end of the rack shaft I9 is mounted'to rotate in a bearing provided in the bracket 5 whilst the outer end of thesaid shaft is similarly mounted to rotate; in a bearing in a further carrier bracket 2| which iszspaced apart from andrigidly connectedzto the bracket 5 by means. of the shaft 2 anda pair. of connecting rods 22. On the rack shaft [5 are secured two ratchetzwheelszii and 24 which, as shown in Figure 1A, are arranged closely. side by side and respectively formed with oppositely directed teeth 23a and. 2411. For co-op'era'tion' with the ratchet wheels 23 and 24=there are provided two oppositely arranged pawls 25 and. 26 for racking round the shaft l9: and hencenal'so the rotary screw 6, through the medium of the. gearing l! and I8,- in respectively opposite d'rrections. The pawls 25 and 26-are pivotally connected toarmsl'l and 28 mountedtoturn freely about the shaft [9, these arms being in turn connected, by means of links 29 and 36, to a common pawl-operating lever 3| adapted to be actuated, through intermediate connections now to be described with reference to Figures 3 and 7, from the main control means of the machine. Thus, the pawl-operating lever 3| is rigidly secured, by means of screws 32 (Figure 3), to a lever 33 which is fulcrummed at 34 upon the right-hand carrier arm I of the pivoted fashioning head. The lower end of the lever 33 is furnished with a roller 35 arranged to make contact with an oscillatory cam 36 freely mounted upon the fulcrum shaft F of the pivoted frame of the fashioning head. The cam 36 is connected, by a link 31, with one arm 38a of a suitably fulcrummed two-armed control lever 38 the other arm 38b of which has fixed therein a stud S upon which is mounted a laterally slidable roller 39. This roller 39 is carried by a lever 40 which is laterally displaceable against the action of a compression spring 4| (Figure 1), and is arranged to be acted upon by a lever 42 fulcrummed Within a bifurcated part 43 fixed on the main frame 44 of the machine (see Figure 1). The lever 42, moreover, is connected at 45 to one end of a flexible cable 46 which works in a tubular housing 41 and is anchored at its opposite end to a lever 46. As shown in Figure 7, the last mentioned lever is fulcrummed at 49 and formed with a nose 48a arranged to be acted upon at required times by cams, such as 50, appropriately arranged on the control drum of the machine. The opposite ends of the tubular housing 41 are respectively secured in the frame 44 and a support 52. For action upon the roller 39 there is provided a continuously rotatable track cam 53 rigidly secured upon the main shaft 54 of the machine. Normally, the spring 41 holds the lever 40 and hence also the rollers 39 clear of the cam 53. The construction and arrangement are therefore such that at required times, determined by the layout of the cams 50 on the control drum 5|, the lever 48 (Figure 7) will be rocked suchwise as to pull the cable 45 and cause the lever 42 to press the lever 40 aside against the spring action thereby moving the roller 39 into the path of the cam 53: as a consequence (and for so long as the roller 39 is allowed to be acted upon by the cam 53) the lever 33 and, through the medium of the link 31, also the cam 36 will be oscillated, these movements being transmitted to the links 29 and 30 through the medium of the combined levers 3i and 33. In this way the two pawls 25 and 26 are operated together.

For determining the direction and extent of racking of the screw 6 there are provided, in association with the oppositely arranged pawls 25 and 26, two bluffs 55 and 56 in the form of discs having cut-away portions (Figures 4, 5 and 6) these bluffs being arranged to be operated conjointly from the control means of the machine in a manner hereinafter to be described. The blufis 55 and 56- are mounted for movement angularly about the rack shaft l9 and are disposed side by side immediately adjacent to the ratchet wheels 23 and 24. The operative arcuate portions 55a and 56a of the peripheries of the bluffs 55 and 56 are on the same radius as the points of the teeth 23a and 24a. The pawls 25 and 26 are formed with lateral extensions 25a and 26a adapted for contact with the said operative arcuate portions 55a and 56a respectively. The cutaway portions of the bluffs are indicated at 55b and 561). Each of the said two bluffs is capable of being disposed in one of three positions, viz. a closed position in which the corresponding pawl will be prevented from turning its ratchet wheel, and two open positions in which the said pawl will be permitted to turn the ratchet wheel to the extent of one or two teeth respectively. In Figure 4, the bluff is shown in its fully open position so as to enable the pawl 25 to turn the ratchet wheel 23 to the extent of two teeth, whilst the bluff 56 is shown closed so that the pawl 26 will be prevented altogether from turning the ratchet wheel 24. In Figure 6, on the other hand, the bluff 55 is shown closed so that the pawl 25 will be prevented from turning the ratchet wheel 23, and the bluff 56 is shown open to the.

extent only of enabling the corresponding pawl 26 to rack round the wheel 23 one tooth. In Figure 5, the bluifs 55 and 56 are so arranged that both pawls will be prevented from turning their respective wheels; the pawl 25 will, however, register with a tooth of the wheel 23. The bluff 56 is controlled by a tension spring 5! (see Figure 4) and is fitted with a stop pin 58 adapted, upon release of the said bluff, to be moved under the action of the spring 51 into contact with a fixed hook-shaped check member 59. Thi check member is so adjusted as to determine the closed position of the bluff 56. To enable the bluff 56 to be accurately set, the check member 59 is mounted for adjustment longitudinally upon a fixed bracket 60 and is adapted to be set, after such an adjustment, by means of screws 6|. The bluff 55 has formed therein a narrow radial slot 550 into which extends a lug 62a formed on a reciprocatory control slide 62 mounted and guided within the fixed bracket 66. The slide 62 is controlled by a tension spring 63. In the bluff 56 there is formed a comparatively wide slot 560, the left-hand edge of which (as viewed in Figures 4, 5 and 6) is also arranged to be acted upon at appropriate times by the lug 62a. Generally speaking, the arrangement is such that when the slide 62 is moved to the left in Figure 4:, the bluff 55 is turned clockwise and closed to prevent racking by the pawl 25 of the ratchet wheel 23, and the bluff 56 is also turned in the same direction against the action of the spring 51 and thereby opened to permit racking by the pawl 26 of the ratchet wheel 24, and vice versa. It will be noted, however, that in the specific arrangement illustrated, a full movement of the slide 62 to the left will cause the bluff 55 to be turned clockwise to an angular extent equal to two ratchet teeth, whereas, by reason of the fact that the slot 560 in the bluff 56 is wider to a predetermined extent than the radial slot 550 in the bluff 55, the bluff 56 will be turned clockwise, after a lag, to the extent of only one tooth. Movements of the control slide 62 in either direction to the permitted varying extents therefore controls the angular extent of the racking of the screw 6. As: shown in Figure 4A, the control slide 62 is furnished with a flanged roller 64 with which is engaged a positioning lever 65 fulcrumed at 66. The positioning lever 65 is formed with a protuberance 65a arranged to be acted upon by a vertically slidable stepped component 67. This component is infiuenced by a tension spring 68, and is adapted to be pulled down to different extents and released at predetermined times by a cable 69 connected and operable by a cam-actuated lever (not shown) at the dictates of cams on the control drum 5| of the machine.

Mounted and operated entirely on the pivoted trauma fashioning same is an auxiliary tank pawl in which, as clearly shown in Figure 3, is provided for action at appropriate times on the ratchet wheel 2 This auxiliary pawl is fulcrumed at Tl upon the carrier arm" I and is adapted to be swung up into an inoperative position clear of the ratchet wheel 24, or released so as todrop 'into engagementwith the teeth 24a of the said Wheel, according to requirements, at the dictates ofc'ams on the control drum; through the medium ofa cable 12 connected atits' appropriate endto the tail portion b of the shank 70d of the pawl Ill. The sha'nk 70a is slotted at 10c for slidable' engagementwith the fulcrum H, and the auxiliary pawl is influenced by a-tension spring 13 oneend of which is anchored to the said shank and the other end to the carrier arm I. Provided on" the shank 70a and depending from the lower edge thereof is a lug 14 arranged to be acted upon by the-leading end of an adjustable screw 'mounted anupward extension 36a of the aforementioned oscillatory cam 36. Thus, at each forward swing of the cam 36, the two main pawls and 26 will simultaneously have imparted thereto an operative stroke, as previously described, whilst at each'backvvard swing of the said cam theauxiliary rack pawl Til is movedforward; 1. e. has imparted thereto an operative stroke againstthe action of the spring 73. In other words, when the main pawls' 2 5 and 26- are making operative strokes, the auxiliary pawl 10 is making an idle stroke, and vice versa. Whenever the auxiliary pawl 18 is in action, the shaft i9 is moved two steps forward and one back, although, of course, this-is only one arrangement'which may be varied, according to requirements. Moreover, the con- .struction'and arrangement are such that all of the racking movements, both main and'auxiliary, are efiected andcontrolled fromthe same cam 53 on the-maincam shaft 54.

As will be appreciated, unless some means are provided for limiting the extents of the movemerits of the threaded transfer point carriers 1- and 81in both directions, there wou-ldbe' a risk of breakage and other damage to the machine in the event of the latter being or becoming incorrectly timed- The extents of the movements of these carriers is limited, according to this in vention, by the means new t'o-be described:

The rack shaft I9 extends through an exteriorly and finely threaded sleeve 56" which is rigidly. secured in the carrier bracket 21. This threaded sleeve extends laterally inwards for some distance from the carrier bracket?!" and, in effect, serves as an additional bearing'foifthe racks haft'lfl. Engaged with the finely threaded sleeve F5 is a complementari ly internally threadeddrum-lilw nut Ti'havin'gfoi'rned thereon two angularly spaced an'd o'utwardly'extend ing contact lugs 78' and 19'; The Hut 'i'l', moreover, is longitudinally grooved at 11a for engagemeht with a driving'arrr; 88 projecting later} allyfrom a collar fil'fix'ed'up'o'n the rackshaft l9 adjacent to the bluff's 55' and 56. The inner end of the driving arm' Bllis attached to the collar 8] by'n'iean's of screws such as '82; Consequently, whenever the shaft I9 is turned in'either'direc tion by the pawl and ratchet gearing. these movements will be transmitted, via the'drivin'g arm 86, to the nut T! which, by virtue of its engage"- ment'with the relatively fixed threadedsleeve-Hi will be caused to move laterally, either"t'owards' the carrier bracket 2! (one limit) or towards 'the" collar 8! (the other limit).

In association with each of'the pawls' 25 and 8 21? there is" provided a pivoted tmemg member in the farm of a suitably shaped arni. The blufiingmember associated-with: the pawl- 2-5" is-indieate'd by" the numeral 83 and is mounted in a pivoted socket 84" located at one sideof the collar 8-1. The hlufii'n'g member 83" is so arranged that consequent upon a turning movement of the pivoted socket- 84 anti-clockwise (as viewed in Fig ure 3)", it will actupon a-pin 85 fixed in and ext'endi'n'g laterally from anupstanding' lug or ear 2511 on the pawl 25 suchwise as to lift the latter clear of the teeth 23d of the ratchet wheel 23, thereby arresting the movement of the rotary screw G-andpennitting-the said pawl to be moved back and-- forth idly. In the pivoted socket 84 is secured a contact piece 36 (Figure 3) arranged so as to be in the pathof; and be acted upon by, thecontact' lug' 18o'n the nut '17- if and when this ever reaches thepredetermined limit of its axial movement to the left-as viewed in Figure 1. Engagement of the Contact piece 8% with the lug TE'tu-rns the pivoted socket B4 andso lifts the p'aw-l 2'5 with the result" aforesaid The bl'ufli'ng member associated with the pawl 2am the other hand; is indicated by the numeral 8 and is mounted in a pivoted socket 8 8 at the opposite side of thecollar 81, this socket extending the full length of the finely threaded sleeve it and having fi-ttedin its (and remote from the blufilng member 81 an intur'ne'd contact piece 88'. This last mentioned contact piece isarranged so as to be inthe path of, and acted upon by, the contact lug T9 on the nut-11 1f and when this'ever reaches the limit of itsaxial movement to the right, i. 6. towards the carrier bracket 21. Engagement'of the contact-piece- 89' with the his 19' turns the elongated pivoted socket-88 in a clockwise directio'n (Figure 3') and thereby swings the bluffihg rheihbe'r'BT outwardsfor action upon a late'ral p'in 90'fix'ed in an upstanding lug or ear 2% on the pawl 26' as a result-ofwhich the latter is lifted clearof the teeth are of the ratchet Wheel 24; The blufhng members 33 and 8'! are influenced by' tension springs-gland 92 respectively.

The Contact lugs l8 and 79 on the nut may, in desired, be adjustable so that any predetermined r'ack' at either end'of thestroke; theblufiingmembers 83 and 87' can be actuated to lift the'pav'vls 25' and 25 clear of the" ratchet wheels 23' and 2t.

A stop arm the form of a lug on the fixed finely threaded'sleeve'lfl is-provided for contact by a stop 94 on thedrum-like n-ut "i-I. when these stops are in contact, the rotary screw 6 is' d'efiniteiypositioned witheach of the threaded carriers 1 and 8 at the appropriate safeoutward limit of its perniitted'lateraltravel and correctly set for the commencement ofa fresh garment or hose'b'la'nk. The said stops can be brought into contact either manually, e. g. by the turning of a handle 95, 01 automatically.

The rack shaft IShas rigidly secured thereon asshown m'or'eclearly in Figure 2, an indexing or check wheel 96 arranged for co-operation with a spring centrolled plunger 91 which is mountedin a'hcusmgss attached to the bracket 5 and isiurnished'with aknob 99 whereby it can be raised clear-"oftheindexing or check wheel, as occasion demands In. the specific example herein described the entirje pawl'and ratchet gearing is mounted on the pivoted franie ofthe fashioning head in such a way ast'o' permit rackingof'the shaft i9 without arrecting -themovements of the said head during transfef'operations'.

What I claim then is:

1. In a straight bar knitting machine, mechanism comprising, in combination, a rotary screw having right-hand and left-hand threaded portions, a pair of threaded members respectively engaged with the said rightand left-hand threaded portions, means adapted to drive the said screw in either direction so that the said threaded members are movable inwards towards each other and outwards away from each other, according to requirements, a pair of movable members each adapted, when actuated, to render the driving means inoperative, means for controlling the driving means, an internally threaded stop component, a fixed complementarily threaded body with which the stop component is en gaged, means for conveying rotary motion to the stop component from the means for driving the screw whereby as the said component is turned in either direction in sympathy with the movements of the screw it will also, by virtue of its engagement with the threaded body, he traversed laterally in the relevant direction towards a limit, and a pair of projections on the stop component for contact with the aforementioned movable members, whereby whenever the threaded members are moved inwards towards each other the stop component will be traversed in one direction towards one limit at which (in an emergency) the appropriate projection on the stop component will contact the relevant movable member and so render the driving means inoperative to stop the screw, and whenever the threaded members are moved outwards away from each other the stop component will be traversed in the opposite direction towards the other limit at which (in an emergency) the other projection on the stop component will contact the other movable member with the same result.

2. Mechanism according to claim 1, wherein the pitch of the threads formed on the stop component and the relatively fixed complementarily threaded body is fine compared with the pitch of the right-hand and left-hand threads on the rotary screw, for the purpose specified.

3. In a straight bar knitting machine, mechanism comprising, in combination, a rotary screw, at least one complementarily threaded member engaged with said screw, controlled means adapted to drive the said screw in either direction and so traverse the threaded member to either side, according to requirements, a pair of movable members each adapted, when actuated, to

render the driving means inoperative, an internally threaded stop component, a fixed complementarily threaded body with which the stop component is engaged, means for conveying rotary motion to the stop component from the means for driving the screw whereby as the said component is turned in either direction in sympathy with the movements of the screw it will also, by virtue of its engagement with the threaded body, be traversed laterally in the relevant direction towards a limit, and a pair of projections on the stop component for contact with the aforementioned movable members, whereby when, in an emergency, the threaded member is in danger of being traversed to either side beyond a normally safe position, the stop compo nent will be moved right to the limit in the appropriate direction where the relevant projection thereon will contact and actuate the corresponding drive-interrupting member suchwise as to stop the rotary screw.

4. Mechanism according to claim 3, wherein the pitch of the threads formed on the stop component and the relatively'fixed complementarily threaded body is fine compared with the pitch of the right-hand and left-hand threads on the rotary screw, for the purpose specified.

5. Mechanism according to claim 3, wherein gearing is provided between the rotary screw and a drive shaft with which are associated the means for driving the said screw in either direction, and the ratio of the gears is such as to ensure that the movements of the stop component between the two limits are small compared with the movements imparted by the screw to the threaded member.

6. In a straight bar knitting machine, mechanism comprising, in combination, a pivoted fashioning head, right-hand and left-hand groups of transfer points provided on said head, threaded carriers for the said points, a rotary screw having right-hand and left-hand threaded portions with which the said threaded carriers are engaged, a drive shaft, gearing between the rotary screw and the drive shaft, pawl and ratchet gearing for racking round the drive shaft in either direction and so traversing the groups of transfer points laterally towards and away from each other, according to requirements, the said gearing comprising two ratchet wheels with oppositely directed teeth, a pair of oppositely disposed pawls for co-operation with the said wheels, bluffs for controlling engagement of the said pawls with the ratchet wheels, control means for timing the bluffs so as to determine the direction and extent of turning movement imparted to the screw, additional blufling means operable to render the pawl and ratchet gearing inoperative at required times and stop means including a component which, during normal working of the machine, moves idly back and forth between two limits in sympathy with the movements of the transfer point carriers, whereby when, in an emergency, the groups of transfer points are in danger of travelling beyond their normally safe positions, the stop component will be moved right to the limit in the appropriate direction and there function to cause actuation of the additional bluffing means and so stop the rotary screw.

'7. In a straight bar knitting machine, mechanism comprising, in combination, a pivoted fash ioning head, right-hand and left-hand groups of transfer points provided on said head, threaded carriers for the said points, a rotary screw having right-hand and left-hand threaded. portions with which the said threaded carriers are engaged, a drive shaft, gearing between the rotary screw and the drive shaft, pawl and ratchet gearing for racking round the drive shaft in either direction and so traversing the groups of transfer points laterally towards and away from each other, according to requirements, the said gearing comprising two ratchet wheels with oppositely directed teeth, a pair of oppositely disposed pawls for co-operation with the said wheels, bluffs for controlling engagement of the said pawls with the ratchet wheels, control means for timing the bluffs so as to determine the direction and extent of turning movement imparted to the screw, an internally threaded stop component, a fixed complementarily threaded body with which the stop component is engaged, means for conveying rotary motion to the stop component from the pawl and ratchet gearing whereby as the said component is turned in either direction in sympathy with the movements of the screw it will also, by virtue. of its engagement with the threaded body, be traversed laterally in the relevant direction towards a limit, a pair of spaced projections on the stop component, and, in association with each of the pawls, an additional blufiing member adapted to be actuated, in anemergency, by one of the projections on the stop component for the purpose of moving the said pawl clear of the corresponding ratchet wheel and so interrupting the drive to the screw, the construction and arrangement being such that during normal working of the machine the stop component will move idly back and forth between the twolimits but that when, in an emergency, the groups of transfer points are in danger of travellingbeyond their normally safe positions, the stop component will be moved right to the limit in the appropriate direction and there function to actuate the relevant addition bluffing member with theresult described.

8. Mechanism according to claim 7, wherein the stop component is grooved for engagement with a driving arm pro ecting laterally from a collar fixed upon the drive shaft.

9. Mechanism according to claim 8, wherein the drive shaft has secured thereon an indexing or check wheel arranged for co-operation with a plunger adapted to be moved clear of the said wheel as occasion demands.

10. In a straight bar knitting machine, mechanism comprising, in combination, a pivoted fashioning head, right-hand and left-hand groups of transfer points provided on said head, threaded carriers for the said points, a rotary screw having right-hand and left-hand threaded portions with which the said threaded carriers are engaged, pawl and ratchet gearing for racking round the screw in either direction for the purpose of traversing the groups of transfer points laterally towards and away from each other, according to requirements, means for controlling the operation of the pawl and ratchet gearing, blufiing means operable to render the pawl and ratchet gearing inoperative at required times, a stop component in the form of an in-- I ternally threaded nut having a stop thereon, a fixed exteriorly threaded cylindrical body with which the said stop component is engaged, the said body being provided with a stop for contact by the stopon the stop component so that when these stops are in contact the rotary screw will be definitely positioned with each of the threaded transfer point carriers at the safe outward limit of its permitted lateral travel, and means for con-' veying rotary motion to the stop component from but that when, in an emer ency, the groups-o1 transfer points are in danger of travelling beyond their normally safe positions, the stop component will be moved right tothelimit in the appropriate direction and there function to cause actuation of the 'bluffing means and thereby influence the pawl and ratchet gearing such-wise as to stop the rotary screw.

11. In a straight bar knitting machine, mechanism comprising, in combination, a rotary screw having right-hand and left-hand threaded portions, a pair of threaded members respectively engaged with the said right and left-hand threaded portions, means adapted to drive the said screw in either direction so that the said threaded members are movable inwards towards each other and outwards away from each other, according to requirements, the said driving means being capable of being influenced suchwise as to effect interruption of the drive and so arrest the movement of the threaded members whenever, in an emergency, the latter are in danger of being moved beyond their normally safe positions, means ,for controlling the driving means, an :internally threaded .stop component, a fixed complementarily threaded body with which the stop component is engaged, and means for conveying rotary motion to the stop component from the means for driving the screw so that as the said component is turned in either direction in sympathy with the movements of the screw it will also, by virtue of its engagement with the threaded body, be traversed laterally in the relevant direction towards a limit, whereby whenever the threaded members are moved inwards towards each other the stop component will be moved in one direction towards one limit at which (in an emergency) it functions to influence the driving means for the purpose specified, and whenever the said members are moved outwards awaykfrom each other the stop component will be moved in the opposite direction towards the other limit at which (also in an emergency) it functions similarly to influence the driving means.

12. Mechanism according to claim 11, wherein the rotary screw is geared to a drive shaftwith which are associated the means for driving the screw in either direction, and the internally threaded stop component is rotatable together with and movable laterally relatively to the said shaft. ALFRED PERCY SAUNDERS.

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

UNITED STATES PATENTS Number Name Date 1,935,408 Lieberknecht Nov. 14, 1933 1,957,068 Schweistres July 17, 1934 2,076,127 Howie Apr. 6, 1937 2,489,141 Kaul et a1 Nov. 22, 1949 2,489,658 Miller Nov. 29, 1949

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