Roving or sliver clamping device for a drafting frame or a spinning machine

A roving clamping device for use in a drafting unit of a spinning machine, said drafting unit having an upper inlet roller and a lower inlet roller engaging a roving between them, said device comprising:

• clamping means swingable to enter between said upper inlet roller and said lower inlet roller to raise the upper inlet roller from the lower inlet roller for clamping a roving against said upper inlet roller in an operative position of said clamping means;
• actuating means operatively connected with said clamping means and including a first force-generating element biasing said clamping means in a direction of movement into said operative position and freely shiftable in said direction at all times by a first force contributed by said element;
• and
• holding means for retaining said actuating means against said force for holding said actuating means against movement in said direction solely by force balance and without a mechanical locking of said actuating means, said holding means including:
• a second force-generating element operatively coupled to said actuating means for generating a second force acting counter to said first force contributed by said first force-generating element, and
• means connected to one of said force-generating elements for controlling same to relieve the effect of said second force and release said actuating means so that said first force can insert said clamping means between said upper inlet roller and said lower inlet roller.