Two types of Grinding Roller are available
i) Long roll grinder ii) Traverse Grinder.
1. Long roll grinder:
It is a steel shaft about 7 inch in dia and 42 to 47 inch long. The roll is carried on a shaft about 1. 125 " in dia. The grinder roll is entirely covered with emery fillet.
It is equipped with, a traverse motion to give a short (endwise) traverse. The usual length of traverse is 3/4 inch. The. drive to long roll grinder is given as shown in the fig. 2. Traverse Grinder:
This consists of a narrow roll, 3. 5 " wide and 7" in dia (mounted on a hollow steel shell 46" long. Within the hollow shell is the traverse screw, a long central shaft in which are cut two wide threads, one right hand and one left hand, which join at the two ends. This makes art endless spiral path around
the shaft which reverses at each end and returns. There is a follower which projects from the narrow grinding roll, through a long slot in the shell into the thread of the screw. By turning the shell the grinding roll is turned for grinding. By turning the screw at different rate of speed than that of the shell, the grinding roll is made to traverse to and for across the card.
The shell is driven by a band from cylinder pulley and so turns the 22 gear. The 16T and 15T gears are fast together and are driven from 22 T gear. The 15 T gear turn the 23 gear, which engage with the end of the screw.
so, for one one rotation of shell, the turns of the Screw is (22 X 15)/(16 X 23) = 0.897
This means screw losses 0.103 turns for every turn of shell. Pitch of the screw is 1. 5 inch. So, for one turn difference between screw and shell, the grinding roller moves 1. 5 inch. But here difference is 0. 103 turns. So 0.103 x 1.5=0.1545 inch is moved (Grinding Roller) for one turn of the shell.
By changing the gear we can alter the traverse per minute of Grinding roller.
BACK OF POINT GRINDING:
The direction of rotation for metallic wire grinding are normally arranged so that the Back edge of the tooth is first to pass under the grind stone.
This method of grinding is safe to use in practice and is by far the most widely accepted method used in mills, giving perfectly satisfactory results.
But with the disadvantage of leaving a temporary rough edge or burr, on the important leading edge of the carding tooth.
This burr tends to mask the real condition of the true leading edge so that experience is necessary to access the precise state of leading edge when making microscopic examination following grinding:
AGAINST THE POINT GRINDING:
In this method of grinding whereby the leading edge of the tooth is first to pass under the grind stone, so that the grinding burr is formed at the back edge of the point.
This leaves the leading edge clear for examination of the true condition after grinding. However, a marked disadvantage is the real danger of serious accident to operators because the points are leading during grinding operation and this method is sot to be recommended.
TOP GRINDING: This consists of grinding away the top of the wire to make the top end of every wire flat and in the sake plane as all other. This gives what is called a chisel point.
SIDE GRINDING OR NEEDLE GRINDING: This consists of grinding away the little from the side of- each point making it some what narrower at the point.
PLOW GRINDING: This consists of grinding the sides of each wire so as to leave more space for the cotton fibres, this gives a tapered point.
