Device for displacing a tenser in a two-for-one twister

A device for displacing a tenser in a two-for-one twister, comprising:

• a cylindrical housing;
• a lower supporting member secured within the housing;
• a yarn guide pipe inserted into the housing and being movable up and down;
• an upper supporting member secured to the yarn guide pipe;
• a tenser held between the lower supporting member and the upper supporting member;
• a means for locating upper and lower positions of said yarn guide pipe;
• a spring for axially urging the yarn guide pipe;
• and
• a magnet provided on the housing to attract and hold the tenser at a position displaced from a yarn running area;
• wherein the means for locating upper and lower positions of the yarn guide pipe comprises a pin and a cam member formed with a cam groove in engagement with the pin;
• wherein said pin is provided to be projected into the housing, and said cam member has a cam groove for locating upper and lower positions of the yarn guide pipe, said cam member being rotatably disposed around the yarn guide pipe whereby said cam groove is formed about the outer periphery of the yarn guide pipe;
• and
• wherein the cam groove comprises a first recess for determining a lower position of the cam member, a second recess for determining an upper position of the cam member, a first guide groove and a second guide groove to make the first recess continuous to the second recess, and a third guide groove to make the second recess continuous to the first recess to thereby form a guide groove in the form of a closed loop.