Dispenser for viscous materials

A dispenser for paste and other viscous materials, comprising a carrier including a housing having an open end;

• a cylinder movably mounted in and extending into said housing through said open end, said cylinder defining a material-confining chamber having a first end and a second end and said cylinder including a tubular wall surrounding said chamber and a wall member at said one end of said chamber, said wall member having at least one material-discharging outlet in communication with said chamber;
• a piston movably installed in said tubular wall at the other end of said chamber, said piston including a bottom wall adjacent said chamber and a skirt adjacent said tubular wall, said cylinder being movable relative to said housing in a first direction to move said wall member toward said piston with resulting expulsion of material from said chamber by way of said at lest one outlet and a reduction of the effective volume of said chamber, and in a second direction counter to said first direction;
• and means for coupling said cylinder with said piston for movement in said second direction so that the effective volume of the chamber remains at least substantiallly unchanged during joint movement of said cylinder and said piston in said second direction, said coupling means including resilient means for biasing said skirt against said tubular wall.