US2972874A

US2972874A - Positive needle cam motion

Info

Publication number: US2972874A
Application number: US704071A
Authority: US
Inventors: Arthur J Cobert
Original assignee: BEAUTIFUL BRYANS Inc
Current assignee: BEAUTIFUL BRYANS Inc
Priority date: 1957-12-20
Filing date: 1957-12-20
Publication date: 1961-02-28
Anticipated expiration: 1978-02-28
Also published as: DE1180085B; NL6515638A; FR1217716A; GB908235A; BE572548A

Description

Feb. 28, 1961 A. J. COBERT POSITIVE NEEDLE CAM MOTION 2 Sheets-Sheet 1 Filed Dec. 20, 195? Feb. 28, 1961 A. J. COBERT 2,972,874

POSITIVE NEEDLE CAM MOTION Filed Dec. 20, 195-: 2 Sheets-Sheet 2 PGSITIVE NEEDLE CAM MOTION Arthur J. Cohert, (Ihattanoog'a, Tenn., assignor to Beau- I tiful Bryans, Incorporated, Chattanooga,'Tenn., a corporation of Tennessee Filed Dec. 20, 1957, Ser. No. 704,071

9 Claims. 01. 66-82) The present invention relates to animproved needle motion for a flat full-fashioned knitting machine.

It is a principal object of the invention to provide an improved vertical needle motion for use in such machines adapted to operate at very high speeds, in which the upward and downward movements of the needles are effected by means of separate up and down cam and follower connections.

It is more specifically an object of the invention to provide a vertical needle motion of this description which is constructed and arranged to effect the relatively extended high speed up and down movements of the needle bars along the length of the machine with smoothness and accuracy and with a minimum of vibration and jar to the machine.

It is a further object of the invention to provide a needle vertical motion having separate cam and follower connections for effecting respectively the upward and.

downward movement of the needles in which provision is made for idle coursing of the needles in a low inoperative position.

The positive needle motion both in the downward and upward direction is effected by operation of separate up and down needle cams and follower connections associated therewith which include separate needle motion up and down cam levers disposed in balanced -relation at opposite sides of the main cam shaft. This construction has the important advantage that a positive and accurate operation of the needles is insured even at very high speeds, and any tendency to vibration of the machine is at the same time reduced to a minimum. The operation of the machine is thus made smoother and a better fabric is produced. The illustrated construction which includes devices for separately disabling and disconnecting the operation of the needle motion up and down follower connections has the additional advantage that it provides for an automatically controlled idle coursing of the needles which is well adapted for use in connection with the automatic insertion and removal of the carriers from the needle field.

A feature of the invention consists in the provision of a device which acts independently of the similarly contoured needle up and down cams to support the needle vertical motion up and down cam follower levers in a predetermined angular relationship which may be adjusted to control the pressure exerted by the follower connections against the respective needle up and down cams, while at the same time the two levers are held against separation by a much heavier spring pressure sufficient to prevent the cam followers from leaving their respective cams. The construction has the particular advantage that the follower levers are at all times maintained in operative position with respect to their cams regardless of any irregularities or differences of contour which may exist as between the two cams. I

The several features of the invention together with the advantages to be obtained thereby will be readily appreciated by one skilled in the art from the following 2,972,874 Patented .Feb. 28, 1961 description taken in connection with the drawings in which:

Fig. 1 is a somewhat fragmentary section through the base of a full-fashioned knitting machine illustrating particularly the needle vertical motion mechanism;

Fig. 2 is an exploded isometric view of substantially the parts shown in Fig. 1; and

Fig. 3 is a detail perspective view of the latch member and pivotal support for the same normally connected betweenrthe needle'vertical motion up and down cam levers.

The positive needle cam motion which forms the subject matter of the present invention is shown as embodied in a full fashioned knitting machine of ordinary description, portions of the machine frame shown including a lower front rail 4, a rear rail 6 and a sinker rail 8. The

on pivot shaft 14 which is in turn carried by horizontally.

extending lever arms 16 secured to a needle vertical motion rock shaft 18 which extends parallel to the cam shaft 10 along the length of the machine.

Referring specifically to Fig. 1, vertical movements are imparted to the needle bar in an upward and downward direction respectively by means of a needle bar down cam 20 and a needle bar up cam 22, said

cams

20 and 22 being rigidly secured to the main cam shaft 10. Movement in a down direction is imparted to the needle bar from the cam 26 through connections which include a downwardly extending follower lever 24 with follower roll 25 secured to a hub 26on the needle vertical motion rock shaft 18. Movements are imparted to the needle.

' bar in an up direction from the needle bar up cam 22' through connections which include a follower lever 28 with follower roll 29 which is pivotally connected together with a short reinforcing arm 3! to the hub 26 on the needle vertical motion rock shaft 13.

As will be evident from a consideration of the drawings the follower lever 24 with follower roll 25 engages against cam 20 at one side of the cam shaft 10, whereas follower lever 28 with follower roll 29 engages against its cam 22 at the opposite side of the cam shaft 10. The two earns 26} and 22 are contoured to maintain constant the angular relation between the two follower levers 24 and 28.

The two levers 2d and 28 are held positively apart in the angular relation referred to established by the contours of the cams 2t), 22 by a spacer member 34 against the pressure of a heavy spring 36. The spacer member 34 which is in the form of a flat plate or bar having a right angle offset at its left hand as seen in Fig. 2 to which is fitted a small shaft extension 38 which is an ranged to pass through an aperture formed in a swivel pin 40 mounted on the-cam lever arm 28. The spacer member 34 is releasably connected to the needle bar down cam follower lever 24 by the engagement of a notch formed in the spacer member 34 with a pin 41 on the follower lever 24. The spacer member 34 is biased against the pin 41 by means of a tension spring 42 connected between the spacer member 34 and a pin on the follower lever 24. The shaft extension 38 is threaded to receive thereon an adjustable stop washer 44 which engages against the swivel pin 49 which thus provides a means of adjustment of the amount of spread between the two levers 24, 28. The cam levers 24, 28 are drawn towards one another by means of a powerful compression spring 36 which is coiled about the shaft'extension 38 and is seated at one end against the swivel pin ttl'and at its other end against

lock washers

48 and 50 threaded. to the outer end of the shaft extension 38 so that the aerasvc -1 shaft extension 38 is drawn through the swivel pin 4% to a position determined by the engagement of the stop washer 44 therewith. The compression spring 36 thus acts to-draw the two follower levers 24, 2% toward one another and to hold the

respective follower rolls

25, 29 against their cams at a pressure which is determinedby the adjustment of the stop washer 44.

The above described arrangement permits the follower levers 24, 23 to be held in the spaced relation determined by the contours of the two cams 2t), 22 and by the spacer member 34 under a pressure sufliciently heavy to prevent any possibility of separation under the stresses of high speed operation, while at the same time the actual pressure with which the

follower rollers

25, 29 are forced against the earns 21 22 is held to a predetermined low value by the adjustment of the stop washer 4 The cams will thus not be subjected to undue wear, while at the same time up cam lever 28 and follower 29 are held in position with relation to the down cam lever 2dto avoid any yield in the parts during the up movement of the needle bar. The spring 36 does permit the follower levers 24- and 28 to yield with relation to one another if any irregularity exists in the contours of the cams so that the levers may spread slightly to take up the shock of any such. irregularity or deviation in the cam contours. The resulting deformation of the heavy spring 36 in any event would be so slight so as to not cause any noticeable deformation in the needle motion. In this connection, it will be noted that there is a mechanical advantage between the cam rollers and the length of movement of the individual needles in a ratio of approximately 2 to 1.

For the performance of narrowing operations, it will be understood that each of the

earns

20, 22 above described will have mounted adjacent thereto a corresponding separate narrowing cam for eifecting respectively the up and down movements of the needle bars for narrowing. These narrowing cams are contoured to oppose each other in the same manner as the knitting cams 22 and to preserve unchanged the established angular spacing between the needle up and down cam levers 24, 28. When the main cam shaft 19 is shifted longitudinally to the narrowing position, the

rollers

25, 29 will be transferred from the main cams 2d, 22 to the narrowing cams in the usual manner and will similarly be transferred back to their.

knitting cams when the cam shaft id is returned to the knitting position.

In accordance with the invention the separate up and down cam actuated needle vertical motion above described is particularly constructed and arranged to be shifted between active operation and an idle coursing position in which the needles are held in a low inoperative position suitable for the introduction and removal of yarn carriers from the knitting zone in accordance with an automatic cycle of operation of the machine. In order to condition the separate up and down cam actuated needle vertical motion cam follower levers 24 and 28 above de-. scribed for idle coursing the down motion cam follower lever 24- which is positively connected to the needle rock shaft 18 is latched in its extreme outward position from the cam shaft in which the needles are down, and at the same time the needle up motion cam lever 28 is rendered inoperative to raise the needles by disengagement of the spreader member 34. The up cam lever 28 continues to move idly, being held against its cam 22 by means of a light spring 54 connected between the lever arm 28 and lever arm 24.

The mechanism by means of which these operations of disconnecting the needle up motion cam lever 28 and of locking the needle down cam lever 24 in the idle coursing position are performed comprises a rock shaft 53 extending along the length of the machine, having at intervals thereon rearwardly extending cam levers such as that shown at 60 in Fig. 2 provided with a follower roller 62 adapted for engagement with an idle coursing cam 64. The follower roller 62 is axially shiftable on a pivot pin 66 on the follower lever 60 between cam engaging and inoperative positions. A shifting fork 68 pivoted on the follower lever 60 is operatively connected at one end to the follower roller 62 and is connected by means of a Bowden wire 72 with the armature shaft of a. solenoid '74 which is arranged to be operated by connections not specifically shown from the pattern chain of the machine. A small tension spring 75 connected between the shifting fork 68 and a point on the machine tends normally to maintain the follower roller 62 in its disengaged inoperarive position. The mechanism controlled by the cam follower 6% and rock shaft 58 comprises a plurality of rearwardly extending lever arms 76 secured to the rock shaft 58, one such lever 76, as shown in Fig. 2, being associated with each spreader link 34 along the length of the machine. The lever 76 is provided with a laterally extending pin 73 adapted for engagement beneath the forward end of the spreader link 34, so that a rocking movement of the shaft 58 produced by the idle coursing cam .54 will have the eifect of raising the link 34 about the swivel pin 4% to disengage the notch in the link with the pin 41, and thus to disconnect the needle motion up cam lever 28 from its actuating mechanism including the down cam lever 24. At the same time, and as the cam down lever 24 reaches its extreme outward position, a latch lever 3t pivoted at 82 on a bracket 8 secured to the front rail 4 of the machine is rocked upwardly to engage a notch in the latch lever fit with a pin 86 on the lower end of the needle motion down cam lever 24, thus locking the needles in their extreme down position. This movement of the latch St is effected by means of a link 88 connected between the latch lever St) and the idle coursing cam lever 6i). It will be noted that the lever fill, while in its disengaged position is supported on a stop pin 90 mounted on a fixed portion of the machine at a low level which will permit the follower roller 62 carried on the cam lever 66 to be readily shifted between the cam engaging and idle position.

The idle coursing position of the needles may be maintained for a number of revolutions of the main cam shaft 10. During the course of each such revolution while the follower roller 62 is in its cam engaging posi tion the idle coursing cam lever 60 will be moved by means of a suitable contour of the cam 64, not specifically shown, downwardly to its roller transfer position and then upwardly to raise the spreader arm 3 and latch while the needles are down and before the needle motion down cam follower lever 24 would normally start to follow its cam inwardly with the rearward movement of the needle motion cam lever 28. The idle coursing cam 64 is preferably contoured to maintain the idle coursing lever 60, and the spreader lifting lever 76 and latch lever 80 raised until the down motion cam follower lever 24 and roller 25 ride again onto the high portion of the down cam 20. To avoid possible interference of the part the link 38 is yieldably extensible, being made of two relatively separable elements which are normally held together to move as a unit by means of a spring 22.

The adjustment of the spreader bar 34 and its adjusting nut 44 is such as to cause the two

cam follower rollers

25 and 29 to be held under some tension through the spring 36. The reason for this pressure consists in the fact that slight variations have been found to exist invariably in the diameter of the cams. if no pressure were applied on the rollers, there would he places on the periphery of the cams Where there would actually be displacementbetween the rollers, so that the needle bar would not then be held and guided too Well. Any lost motion or tolerance between the rollers and the cams would cause the needle bar to vibrate and not to follow the path of the main cam accurately. Under these circumstances provision must be made to overcome this pressure before it is possible to move the spreader member 34 into and out of engagement with the locking pin 38 as above described. To this end a cutout 97 is provided in the needle bar up motion cam 22 which is located on the half-round portion of the cam and not the working half, that is, on that portion of the cam engaged by the follower roller 29 when the needle bar is moving up and down. This cutout will arrive at the roller 29 during the thread laying part of the coulier motion when the needles are motionless. The cutout 97 is deep enough only to release the pressure between the rollers and their respective cams so that at this time it will be possible to raise and lower the spreader member 34 without difliculty and thus to engage the notch in the spreader member with the mating pin 41. The inward motion of the vertical needle motion up cam lever 6 the spreader member 34 and latch 80 are permitted to fall. When the cam 20 comes under the roller 25, it will raise the needle motiondown cam lever 24 just far enough to release the pressure on the latch 80 which is then permitted to drop down releasing the pin 86. Also the spreader member 34 will drop under the influence of its spring 42 but will not fully engage the recess of the spreader member for the reason that at this point of the knitting cycle there must be some pressure between the

rollers

25 and 29. However, the needle bar 12 will rise because of the tension exerted by the spring 54 as the machine continues to revolve, and the slope of the 28 toward the vertical motion needle down motion cam lever 24 permitted by the cutout 97 is limited by the engagement of a second stop member 98 with the pivot pin for the needle vertical motion up cam lever 28. The stop member 98 is provided with a screw adjustable stop nut 100 screw theraded to the stop member 98 which is rigidly connected with a stop member 102, on the needle vertical motion down cam lever 24. The stop member 98 with its adjustable stop nut 100 is arranged to engage against the abutment 102 at the same time that the roller 29 reaches the cutout portion 97 of the needle up motion cam 22.

The operation of the positive up and down cam and needle motion including the operation during idle coursing will be briefly described as follows:

During the normal operation of knitting or narrowing the vertical needle motion down cam lever 24, and the needle vertical motion up cam lever 28 are locked together through the spreader member 34 so that the

needle bar cams

20 and 22 can impart a positive motion downwardly through cam follower lever 24 to the needles, and thereafter a substantially positive upward motion to cam follower lever 28 backed by the heavy spring 36.

When it is desired to resort to idle coursing, as for example, during the automatic insertion of the reinforcing carriers from storage to their operating position, the machine is first slowed somewhat at least one course prior to the course in which the idler isto be used. Then at the correct revolution in response to a signal from the pattern machine or pattern card depending on the system of automatic control, the solenoid 74 is energized. Roller 62 is shifted from its inoperative position into engagement with an idle coursing cam 64 which is timed to raise the follower lever 60 during the couliering or thread laying part of the cycle. At the same time, the roller 29 of the needle vertical motion up cam lever 28 would have reached the cutout 97 on its cam 22 so that the spreader member 34 at its point of contact with the pin 41 will be freed from the pressure of spring 36, with only the force of spring 42 holding the members 34 down. Then as the idle coursing cam lever 60 rises spring 54 will hold the respective needle up cam lever 28 and needle down cam lever 24 against their

cams

22 and 20 taking the place of the disconnected spring 36.

The machine continues to turn until the needle bar 12 has been lowered by the action of cam 20. As the lever 24 moves outwardly pin 86 will snap into the latch 80 which will then hold the lever 24 stationary. The needle bar is now at its lowest position. As the machine continues to turn the needle bar would normally rise as the needle down cam follower lever 24 tends under the influence of spring 54 to move inwardly following the down slope of its cam 20, but is not permitted to do so because of the engagement of the latch 80 with the pin 86. Needle up motion cam lever 28 however following the contour of the cam will move to the left against the action of the spring 54.

When it is desired to return the needle bar to its working position, the solenoid 74 is released again during the normal thread laying part of the revolution. This action causes the roller 62 to move out of register with the cam 64. Then, as the machine continues to revolve,

cam 20 becomes lower. Then on the next yarn laying stroke as the roller 29 reaches the cutout 97 on the cam 22, the notch formed in the spreader member 34 will drop into engagement with the pin 41, and the idle course cycle is thus completed.

The invention having been described What is claimed 1. In a full-fashioned knitting machine having knitting devices and knitting needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle up and down motion rock shaft, separate cams on the cam shaft contoured to produce respectively the up and down movements of the needles, a needle down cam follower lever positively connected with said rock shaft and arranged for engagement with its cam at one side of the cam shaft, a needle up cam follower lever supported from said rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of the cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, means connected between said needle up and down cam follower levers to maintain constant the angular relation therebetween including a spacing device disposed to limit the relative approach of said follower levers to a minimum angular relation, spring means acting upon said follower levers to maintain said follower levers in said minimum angular relation, and means operable to disconnect said spacing device and said spring means from at least one of said follower levers and thereby to permit a free relative movement thereto, and additional spring means continuously biasing said follower levers against their respective cams.

2. In a full-fashioned knitting machine having knitting devices and knitting needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle up and down motion rock shaft, separate cams on the cam shaft contoured to produce respectively the up and down movements of the needles, a needle down cam follower lever positively connected with said rock shaft and arranged for engagement with its cam at one side of the cam shaft, a-needle up cam follower lever supported from said rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of the cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, and means connected between said needle up and down cam follower levers to maintain constant the angular relation therebetween comprising a spacer member constructed and arranged to permit a relative separating movement of said levers and having means for adjustment to provide a minimum angle of separation between said levers, and yieldable means connected between said needle up cam follower lever and spacer member to maintain said levers in said minimum angle position.

3. ma full-fashioned knitting machine having knitting devices including a series of needles movable as a unit in forward and back and up and down directions, and a aovasve cam shaft, the combination of a needle up and down motion rock shaft, a needle up cam and a needle down cam mounted on the cam shaft for producing respectively the up and down movements of the needles, a needle down cam follower lever positively connected with said rock shaft and adapted to engage its cam at one side of said cam shaft, a needle up cam follower lever pivotally supported from said rock shaft at an angle with relation to said needle down cam follower lever for en gagement with its cam at the opposite side of said cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, a spacing device connected between said needle up and down cam follower levers arranged to maintain said angular spacing between said cam follower levers and including spring means acting between said spacing device and one of said cam follower levers to bias said cam follower levers toward one another, and means acting when rendered operative to disconnect said spacing device from at least one of said cam follower levers.

4. In a full-fashioned knitting machine having knitting devices including a series of needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle up and down motion rock shaft, a needle up cam and a needle down cam mounted on the cam shaft for producing respectively the up and down movement of the needles, a needle down cam follower lever mounted on the rock shaft and adapted to engage its cam at one side of said cam shaft, a needle up cam follower lever mounted from the rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of said cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, means securing one of said follower levers rigidly to the rock shaft, means connected between said needle up and down cam follower levers to maintain a predetermined minimum angular relation therebetween including a spacing device disposed between said follower levers to limit the relative approach of said follower levers, spring means acting upon said follower levers to effect said relative approach of said follower levers and to maintain said levers in said minimum angular position, and means acting when rendered operative to disconnect said spacing device from between said follower levers.

5. In a full-fashioned knitting machine having knitting devices including a series of needles movable as a unit in forward and back and up an down directions, and a cam shaft, the combination of a needle up and down motion rock shaft, a needle up cam and a needle down cam mounted on the cam shaft for producing respectively up and down movements of the needles, a needle down cam follower lever positively connected with said rock shaft and adapted to engage the cam at one side of said cam shaft, a needle up cam follower lever pivotally supported from the rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of said cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, and a spacing device connected between said cam follower levers including a separating member disposed between said cam follower levers and slidably supported on one of them, an adjustable stop member on said separating member for engagement with said lever to provide a minimum angle of separation be tween said levers, and a heavy spring connected between said separating member and lever biasing the lever against said stop.

- 6. In a full-fashioned knitting machine having knitting devices and knitting needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle up and down motion rock shaft, separate cams on the cam shaft contoured to produce respectively the up and down movements of the needles, a needle down cam follower lever positively connected with said rock shaft and arranged for engagement with its cam at one side of the cam shaft, a needle up cam follower lever supported from said rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of the cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the up and down follower levers during rotation of the cam shaft, a spacer member connected between said cam follower levers, a latch operative to lock the needle down cam follower lever in an extreme outward needle down idle coursing position, cam actuated means acting when rendered operative to disconnect one of said cam follower levers from the spacer member, and simultaneously to actuate said latch to lock the needle down cam follower lever in said out'ward idle coursing position.

7. In a full-fashioned knitting machine having knitting devices including a series of needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle motion including a needle up and down motion rock shaft, a needle up cam and a needle down cam mounted on the cam shaft for producing respectively up and down movements of the needles, a down cam follower lever positively connected with said rock shaft and adapted to engage the cam at one side of said cam shaft, an up cam follower lever pivotally supported from the rock shaft at an angle with relation to-said down cam follower for engagement with its cam at the opposite side of the cam shaft from the down cam follower, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, and a spacing device connected between said cam follower levers including a separating member disposed between said cam follower levers having a swiveling sliding connection with the needle up cam follower lever, a separating stop adjustable on the separating member for engagement with said needle up cam follower lever, spring means connected between the needle up cam follower lever and the separating member to engage the needle up cam follower lever against said stop, a pin and slot locking connection between the separating member and the needle down cam follower lever, a latch operative to support the needle down cam follower lever 1n an extreme outward needle down idling coursing posi tion, and means acting when rendered operative to disconnect the separating member from the needle down cam follower lever and for latching said needle down cam follower lever in the outward needle down idle coursing position.

8. In a full-fashioned knitting machine having knitting devices including a series of needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle motion including a needle up and down motion rock shaft, a needle up cam, and a needle down cam mounted on the cam shaft for producing respectively up and down movements of the needles, a needle down cam follower lever posinvely connected with said rock shaft and adapted to engage its cam at one side of said cam shaft, and a needle up cam follower lever pivotally supported from the rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of said cam shaft from the down cam follower, said cams being contoured to maintain constant said angle between the up and down needle cam follower levers during rotation of the cam shaft, and a spacing device connected between said cam follower awas'm levers including a separating member disposed between said cam follower levers having a swiveling sliding connection with the needle up cam follower lever, a separating stop adjustable on the separating member for engagement with said needle up cam follower lever providing a position of minimum separation between said cam follower levers, spring means connected between the needle up cam follower lever and the separating member to engage the needle up cam follower lever against said stop, a releasable connection between the separating member and the needle downcam follower lever and means acting when rendered operative to rotate the separating member about said swiveling connection and thereby to disengage said releasable connection.

9. In a full-fashioned knitting machine having knitting devices including a series of needles movable as a unit in forward and back and up and down directions, and a cam shaft, the combination of a needle up and down motion rock shaft, a needle up cam and a needle down cam mounted on the cam shaft for producing respectively the up and down movement of the needles, a needle down cam follower lever mounted on the rock shaft and adapted to engage its cam at one side of said cam shaft, a needle up cam follower lever mounted from the rock shaft at an angle with relation to said needle down cam follower lever for engagement with its cam at the opposite side of said cam shaft from the needle down cam follower lever, said cams being contoured to maintain constant said angle between the needle up and down cam follower levers during rotation of the cam shaft, means securing one of said followers rigidly to the rock shaft, and a spacing device connected between said 10 needle up and down cam follower levers including a spacer member operatively connected between said cam follower levers to maintain a minimum spacing therebetween, a heavy spring connected between said spacer member and one of said cam follower levers acting to draw said cam follower levers together into said minimum spacing position, means for connecting and disconnecting said spacer member from the other of said cam follower levers, means to latch said needle down cam follower lever in an outward needle down idle coursing position, cam actuated means for disconnecting said spacer member and simultaneously for latching said needle down cam follower lever in said needle idle coursing position, an auxiliary tension spring connected between said cam follower levers, said needle up cam having formed therein a cutout to permit further movement of the cam follower levers toward one another during the cam actuated disconnection of the spacer member, and an auxiliary spacing device interposed between said cam follower levers to limit the further approach movement of said cam follower levers.

References Cited in the file of this patent UNITED STATES PATENTS 978,783 Rose Dec. 13, 1910 2,242,047 Strzalkowski May 13, 1941 2,426,036 Lynam Aug. 13, 1947 FOREIGN PATENTS 512,445 Belgium July 15, 1952