Knitting Cam | Function of Knitting Cam | Action of Knitting Cam

Cams are the devices , which convert the rotary machine drive in to a suitable reciprocating action for the needles and other elements. In general there are two types of cams.
  1. Engineering cam.
  2. Knitting cam.
Engineering cam:  These are of circular type and indirectly control the motions of bares of elements. They are attached to a rotary drive shaft situated parallel to and bellow the needle bar, a number of independent cams correctly aligned movement. The drive is transmitted and adapted cam-followers, levers and rocker shafts. One complete 360-degree revolution of the drive shaft is equivalent to one knitting cycle.

In warp knitting machines four Types of cam have been employed.
  1. Single acting cams
  2. Cam and counter cam
  3. Box cam or enclosed cam
  4. Counter cam/ring cam/pot cam
Due to excessive vibration at speeds above 800 courser/minute for engineering cams eccentric drive is employed where speed is 2000courser/minute or more.

Knitting Cam:  The knitting cam is of angular type and acts directly on to the butt of needles or other elements to produce individual movement in the tricks of needle weft knitting machine as the butts pass through the stationary cam system or the cams pass across the stationary tricks. 
Knitting cam
Knitting cams are attached either individually or in unit form to a cam plate and depending upon the machine design, are fixed exchangeable or adjustable. At each of at least a raising cam, a stitch cam and an up throw cam whose combined effect is required. Usually four main types of knitting cams are used.

i. Raising cam:  The raising cam causes the needle to be lifted to either tuck, clearing loop transfer or needle transfer depending upon machine design.

ii. Stitch cam:  The stitch cam controls the depth to which the needle descends thus controlling the amount of yarn drawn in to the needle loop. It al so a knock-over cam.

iii. Up throw or counter cam:  The up throw or counter cam takes the needles back to the rest position and allows the formed loops to relax.

iv. Guard cam:  The guard cam is often placed on the butts and to prevent needles from falling out of track.

Function of Cam:  The functions of cam are as follows
  1. To produce motion to needles .
  2. To drive the needles.
  3. Formation of loops.
Cam Type:
a. Engineering ----------------------- Circular type
b. Knitting ------------------------------- Angular motion

Engineering cam are 4 types :
  1. Single active .
  2. Cam and counter cam .
  3. Box cam .
  4. Counter cam / pot cam .
Knitting cam are also 4 types :
  1. Stitch cam .
  2. Raising cam .
  3. Up throw cam .
  4. Guard cam .
Knitting action :
  1. Rest position .
  2. Clear position .
  3. Yarn feeding position .
  4. Knock – over –position .
  5. Holding Down position . 


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