GB1566137A

GB1566137A - Loop hold-down device for use in conjunction with a knitting machine

Info

Publication number: GB1566137A
Application number: GB1966/77A
Authority: GB
Original assignee: EWE HOSIERY
Current assignee: EWE HOSIERY
Priority date: 1977-01-18
Filing date: 1977-01-18
Publication date: 1980-04-30
Also published as: DE2802057A1; BE862969A; FR2377465B1; FR2377465A1; JPS53114953A; IT1102292B; IT7847669A0; DE2802057B2; DE2802057C3; CH618483A5; JPS6026858B2

Description

(54) LOOP HOLD-DOWN DEVICE FOR USE IN CONJUNCTION WITH A KNITTING MACHINE (71) We, THE EWE HOSIERY COMPANY LIMITED, a British Company, of Penn Street, Derbyshire, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The subject of this invention is a loop hold-down device for fitting to a knitting machine, particularly a knitting machine of the flat V-bed type having at least two sets of latch needles normally movable diagonally across one another between raised and lowered positions by action of a cam as a carriage carrying the cam moves to and fro across the bed of the machine.

In normal operation of such a machine the loops of yarn being knitted must slide down the raised needles after being formed so that they slip over the latches on to the shanks of the needles preparatory to closing the latches as the needles are retracted. The conventional method of achieving this object is to attach a weight to the end of the formed fabric, the weight causing the fabric to be pulled downwardly thus causing each loop when formed to be pulled down the shank of the associated needle and over the latch.

For the performance of certain knitting operations it is necessary to hold one set of needles static and inoperative with loops of fabric on them while the other set of needles, the active needles, continues knitting. In this case the necessary tension to pull the loops on the active needles down the shanks of the needles cannot be obtained by weights on the knitted fabric because the pull of the weights is supported by the loops on the static needles which are further down the knitted fabric than the loops on the active needles. The result is that the loops on the active needles do not move down over the latches on the active needles as they are formed and a proper knitting action cannot be obtained.Several mechanisms for moving the loops on the active needles are available all incorporating loop hold-down elements, sometimes referred to as presser feet which press into the groove at the junction line formed by the intersection of the layer of fabric being knitted on the active needles and the layer of fabric held static on the static needles. One known construction incorporates a swing arm the lower end of which engages this groove. Some form of longitudinal movement is necessary because the loop hold-down element must be clear of and in advance of the point where knitting is actually taking place and since knitting takes place in both directions of movement of the carriage on such a knitting machine it is necessary for a loop hold-down element always to be present in advance of the knitting point as the direction of knitting reverses across the piece being knitted.The swing arm provides this effect but suffers from the disadvantage that according to the size of the angle of swing the position assumed by the part of the arm in contact with the groove changes. Also according to the size of the angle of swing the longitudinal position of the part of the arm in contact with the groove i.e. its distance from the knitting point, varies.

In another construction two loop holddown elements spaced along the length of the needle rows are alternately engageable with the portion of the groove in advance of the knitting point in each direction of movement of the carriage, each loop holddown element being alternately operative in the to and fro movement of the carriage.

It would be of advantage to be able to eliminate any kind of swinging movement of the loop hold-down element and to be able to set easily the loop hold-down element in the best operative position.

It is an object of the present invention to provide a loop hold-down device which is easily set to engage and hold-down the loops on the active needles in the best chosen position and which operates by simple rectilinear motion.

A loop hold-down device according to the invention incorporates a carrier member attachable to the cam-carrying movable carriage of a flat knitting machine, at least one bar supported by the carrier member and reciprocable and rotatable therein, the bar being reciprocable in a direction which is transverse with respect to the direction in which the carriage is arranged to move When the device is attached to the carriage, means operative to reciprocate the bar in the carrier at the end of each traverse of the carriage between an extended loop engaging position and a retracted inoperative position, means operative to rotate the bar through an angle of 1800 while it is retracted, and a loop hold-down element attached to and projecting from the end of the bar which is lowermost when the device is attached to the carriage, the means for rotating the bar being arranged when in operation to rotate the bar to the position in which the loop hold-down element projects rearwards with respect to the direction in which the carriage is about to move.

Where the carrier member incorporates a single bar with attached loop hold-down element the member may be attachable to the carriage by an attachment permitting the carrier member to slide with respect to the carriage in the same direction as the carriage moves along the needle bed. This is to permit the loop hold-down element to be moved to a position in advance of the cam riage at each traverse of the carriage along the needle bed.

The bar may be of rectangular section, particularly oblong section, the thickness being small enough to permit the bar to penetrate into the groove between the needles of the two beds.

The carrier member may support a cam mechanism engageable by a convenient fixed part of the machine when the carrier member is in position on the carriage so that the cam is actuated at opposite ends of the travel of the carriage to cause the bar to reciprocate and rotate and in a device incorporating a single loop hold-down element the carrier member to slide in the carriage as described.

The cam mechanism may include a cam plate slidable in the carrier member and the cam plate may carry a cam surface engageable with the bar and a rack engageable with a pinion on the bar when the bar is at the appropriate end of its reciprocating stroke so that sliding movement of the cam plate causes the bar to reciprocate and rotate. Alternatively the cam plate may carry only a cam surface and the carrier member may carry a helical cam element formed with a helical cam surface engageable by a cam follower projecting transversely from the bar and engageable with the helical cam surface as the bar nears the retracted position during its reciprocating movement.

The loop hold-down element may be a length of spring wire attachable to the appro priate end of the bar and projecting trans versely from the bar.

The means for rotating the bar is normally so set that when the carrier member is attached to the carriage the loop hold-down element always projects in the trailing direc tion as the carriage moves first one way and then the other.

The cam mechanism may be arranged to urge the bar to move in one direction, spring means being provided to move the bar in the other direction.

The carrier member may support two bars spaced longitudinally with respect to a carriage to which the device is attachable, the two bars being synchronized with one another and operatively coupled preferably to the same cam mechanism so that both bars reciprocate in unison. A helical cam member may be provided for each bar to effect the rotation of the bar. In this construction the carrier member is fixed to the carriage and the two bars are located to be on opposite sides of the knitting point.

A practical embodiment of the loop holddown device of the invention incorporating two loop hold-down elements is illustrated in the accompanying drawings in which Fig.

1 is a side elevation of the device in section and Fig. 2 is a section through the device on the plane indicated by 2-2 in Fio. 1.

In the drawings 1 denotes generally a carrier member attachable to the cam-carrying carriage of a knitting machine i.e. the car riage which supports the cam which is moved along the machine bed to actuate successively the needles in the two rows of needles disposed in V-formation and forming the needle bed. The carrier member 1 supports a block 2 which is slidable along two guide pins 3 in a direction transverse to the direction of movement of the carrier member alona the needle bed. The block 2 supports slidable therein two sleeves 4 within each of which there is disposed a bar 5 to the lower end of which is attached a loop hold-down ele ment. Each bar 5 is rotatable within its sleeve 4 but cannot move axially relatively to the sleeve 4. Springs 7 connected between pins 8 screwed into the block 2 and pins 9 attached to the sleeves 4 urge the sleeves to move downwardly in the block 2 to the extended position illustrated. The block 2 supports a cam follower 10 which engages a cam groove 11 formed in a plate 12 mounted in the carrier member 1 to be slid able throuh the carrier member in a direc tion parallel with the direction of movement of the carrier member along the needle bed.

The cam follower 10 also engages a slot 13 in a plate 14 fixed to the carrier member 1, the slot 13 being parallel to the guide pins 3. A transverse pin 15 mounted in the upper end of each bar 5 is engageable with a helical cam face 16 presented by a helical cam member 17 mounted in the top of the carrier member when the bar 5 is moved to its retracted position. 18 denotes latch neFes disposed diagonally with respect to r3ne another and forming the needle bed.

iln operation af a knitting machine to iich the device illustrated in the drawings is fitted, as the carriage moves along the needle bed in one direction the cam raises and lowers consecutively the needles of one set which may be referred to as the active needles and leaves the other set of needles static, the static needles holding loops pre weusSy formed thereon on the previous transverse of the carriage when they were the active needles.Assuming that the carriage is moving to the right as illustrated in the drawings the cam plate 12 is in the position .ilkSrated with respect to the carrier member so that the bars 5 mounted in the sleeves 4 are in the extended loop-engaging position shown with the loop hold-down element 6 pressing into the angle formed by the crossed needles 18. As the elements 6 are disposed one in advance and one behind the knitting position the loops on the active needles are held down so that they can engage the latches on the active needles as these needles are raised and lowered by the cam as the carriage moves.

When the carriage approaches one end of the needle bed the cam plate 12 supported by the carriage member 1 comes against an abutment at the end of the needle bed and can thus move no farther. Continued movement of the carriage towards the end of the needle bed then causes the cam plate 12 to assume a position relatively to the carrier 1 such that the cam plate 12 projects from the left hand side of the carrier member 1.

As the cam plate 12 moves to the left relatively to the carrier member 1 the cam slot 11 guides the cam follower 10 to rise up to the apex of the cam slot, this action causing the block 2 to slide along the guide pins 3 towards the top of the carrier member 1 retracting the sleeves 4 and the bars 5 held therein. The loop hold-down elements 6 are thus raised out of the groove formed by the two banks of needles 18. When the block 2 approaches the top of its movement the pins 15 supported by the bars 5 engage the helical cam faces 16 and continued upward movement of the block 2 causes the helical cam faces 16 to effect a rotary displacement of the pins 15 causing the bars 5 to rotate through 1800 within the sleeves 4 and causing the loop hold-down elements 6 now to project to the right.As the cam follower 10 passes over the apex of the cam slot 11 the block 2 is moved towards its lowermost position again, assisted by the action of springs 7. The downward movement continues until the loop hold-down elements 6 are again fully extended and resting in the angle between the needles 18. The carriage is then ready to begin its movement in the opposite direction along the needle bed. As the cam plate 13 is now projecting from the new leading end of the carrier member it is ready to operate when the other end of the needle bed is reached to raise and rotate the loop hold-down elements to cause them to project again to the left.

In the form of the device incorporating only a single loop hold-down element and having consequently only one reciprocable bar the carrier member is mounted on the carriage to be movable with respect to the carriage. The operation of retracting and rotating the loop hold-down element is performed exactly as described in connection with the carrier member incorporating two loop hold-down elements but this time when the carriage comes to each end of the needle bed the carrier member is moved along the carrriage far enough to transfer the single loop hold-down element from one side of the needle-actuating cam to the other so that in each movement along the needle bed the single loop hold-down element is always in advance of the knitting point.

WHAT WE CLAIM IS:- 1. A loop hold-down device incorporating a carrier member attachable to a camcarrying movable carriage which is a normal part of a flat knitting machine, at least one bar supported by the carrier member and reciprocable and rotatable therein, the bar being reciprocable in a direction which is transverse with respect to the direction in which the carriage is arranged to move when the device is attached to the carriage, means operative to reciprocate the bar in the carrier member at the end of each traverse of the carriage between an extended loop engaging position and a retracted inoperative position, means operative to rotate the bar through an angle of 1800 while it is retracted and a loop hold-down element attached to and projecting from the end of the bar which is lowermost when the device is attached to the carriage, the means for rotating the bar being arranged when in operation to rotate the bar to the position in which the loop hold-down element projects rearwards with respect to the direction in which the carriage is about to move.

2. A loop hold-down device as claimed in claim 1 incorporating a single bar in which the carrier member is furnished with an attachment by which the carrier member may be attached to the carriage while permitting the carrier member to slide with respect to the carriage in the same direction

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

the slot 13 being parallel to the guide pins 3. A transverse pin 15 mounted in the upper end of each bar 5 is engageable with a helical cam face 16 presented by a helical cam member 17 mounted in the top of the carrier member when the bar 5 is moved to its retracted position. 18 denotes latch neFes disposed diagonally with respect to r3ne another and forming the needle bed.

iln operation af a knitting machine to iich the device illustrated in the drawings is fitted, as the carriage moves along the needle bed in one direction the cam raises and lowers consecutively the needles of one set which may be referred to as the active needles and leaves the other set of needles static, the static needles holding loops pre weusSy formed thereon on the previous transverse of the carriage when they were the active needles.Assuming that the carriage is moving to the right as illustrated in the drawings the cam plate 12 is in the position .ilkSrated with respect to the carrier member so that the bars 5 mounted in the sleeves 4 are in the extended loop-engaging position shown with the loop hold-down element 6 pressing into the angle formed by the crossed needles 18. As the elements 6 are disposed one in advance and one behind the knitting position the loops on the active needles are held down so that they can engage the latches on the active needles as these needles are raised and lowered by the cam as the carriage moves.

When the carriage approaches one end of the needle bed the cam plate 12 supported by the carriage member 1 comes against an abutment at the end of the needle bed and can thus move no farther. Continued movement of the carriage towards the end of the needle bed then causes the cam plate 12 to assume a position relatively to the carrier 1 such that the cam plate 12 projects from the left hand side of the carrier member 1.

As the cam plate 12 moves to the left relatively to the carrier member 1 the cam slot 11 guides the cam follower 10 to rise up to the apex of the cam slot, this action causing the block 2 to slide along the guide pins 3 towards the top of the carrier member 1 retracting the sleeves 4 and the bars 5 held therein. The loop hold-down elements 6 are thus raised out of the groove formed by the two banks of needles 18. When the block 2 approaches the top of its movement the pins

15 supported by the bars 5 engage the helical cam faces 16 and continued upward movement of the block 2 causes the helical cam faces 16 to effect a rotary displacement of the pins 15 causing the bars 5 to rotate through 1800 within the sleeves 4 and causing the loop hold-down elements 6 now to project to the right.As the cam follower 10 passes over the apex of the cam slot 11 the block 2 is moved towards its lowermost position again, assisted by the action of springs 7. The downward movement continues until the loop hold-down elements 6 are again fully extended and resting in the angle between the needles 18. The carriage is then ready to begin its movement in the opposite direction along the needle bed. As the cam plate 13 is now projecting from the new leading end of the carrier member it is ready to operate when the other end of the needle bed is reached to raise and rotate the loop hold-down elements to cause them to project again to the left.

In the form of the device incorporating only a single loop hold-down element and having consequently only one reciprocable bar the carrier member is mounted on the carriage to be movable with respect to the carriage. The operation of retracting and rotating the loop hold-down element is performed exactly as described in connection with the carrier member incorporating two loop hold-down elements but this time when the carriage comes to each end of the needle bed the carrier member is moved along the carrriage far enough to transfer the single loop hold-down element from one side of the needle-actuating cam to the other so that in each movement along the needle bed the single loop hold-down element is always in advance of the knitting point.

WHAT WE CLAIM IS:- 1. A loop hold-down device incorporating a carrier member attachable to a camcarrying movable carriage which is a normal part of a flat knitting machine, at least one bar supported by the carrier member and reciprocable and rotatable therein, the bar being reciprocable in a direction which is transverse with respect to the direction in which the carriage is arranged to move when the device is attached to the carriage, means operative to reciprocate the bar in the carrier member at the end of each traverse of the carriage between an extended loop engaging position and a retracted inoperative position, means operative to rotate the bar through an angle of 1800 while it is retracted and a loop hold-down element attached to and projecting from the end of the bar which is lowermost when the device is attached to the carriage, the means for rotating the bar being arranged when in operation to rotate the bar to the position in which the loop hold-down element projects rearwards with respect to the direction in which the carriage is about to move.
2. A loop hold-down device as claimed in claim 1 incorporating a single bar in which the carrier member is furnished with an attachment by which the carrier member may be attached to the carriage while permitting the carrier member to slide with respect to the carriage in the same direction

as the carriage is arranged to move along the needle bed.
3. A loop hold-down device as claimed in claim 1 in which the bar is of rectangular section.
4. A loop hold-down device as claimed in claim 1 including a bar-operating mechanism engageable by a convenient fixed part of the machine when the device is mounted on the carriage of a knitting machine and the carriage is at the ends of its travel whereby to cause the bar-operating mechanism to operate to cause the bar to reciprocate and rotate.
5. A loop hold-down device as claimed in claim 4 in which the bar-operating mechanism includes a cam plate slidable in the carrier member and presenting a cam surface engageable with the bar and operative to communicate reciprocating movement to the bar and a rack engageable with a pinion on the bar so that the sliding movement of the cam plate causes the bar to reciprocate and rotate.
6. A loop hold-down device as claimed in claim 4 in which the bar-operating mechanism includes a cam plate slidable in the carrier member and presenting a cam surface engageable with the bar and the carrier member carries a helical cam element formed with a helical cam surface engageable by a cam follower projecting transversely from the bar and engageable with the helical cam surface for rotating the bar as the bar nears the retracted position during its reciprocating movement.
7. A loop hold-down device as claimed in claim 4 in which the carrier member supports two bars spaced longitudinally with respect to a carriage to which the device is attachable, each bar supporting a loop holddown element, the two bars being synchronized with one another and operatively coupled to the same bar-operating mechanism which is a cam mechanism so that both bars reciprocate in unison and each bar carries a cam follower engageable with a helical cam member when the -bar is re tracted, said helical cam member being operative to rotate the bar through 1800.
8. A loop hold-down device as claimed in claim 7 in which the carrier member supports a block guided to move in a direction transversely of the direction of movement of the carriage to which the device is attachable, said block supporting slidable therein and spaced in the direction of movement of the carriage two parallel sleeves in each of which a bar supporting a loop hold-down element is rotatably supported, the block presenting a cam follower engaged with a cam surface formed in a cam plate slidable in the carrier member in the same direction of movement as the carriage to which the carrier member is attachable, said cam surface being so shaped that during sliding movement of the cam plate relative to the carrier member the cam plate is operative to cause the block to move transversely of the direction of movement of the carriage whereby to cause the bars to move from an extended position to a retracted position and back to the extended position and each bar carrying a transversely projecting cam follower engageable with a helical cam surface on a helical cam element supported by the carrier member when the bars are moved to the retracted inoperative position, the helical cam elements being operative to rotate the bars within the sleeves through an angle of 1800.
9. A loop hold-down device substantially as described with reference to the accompanying drawings.