| abstract |
The invention relates to a device for administering a fluid, comprising a cylinder (13), a plunger (26) which can be moved in the cylinder (13) between a front and rear end position and which is connected to a plunger rod (25), and a clamping device (S) which is connected to the plunger rod (25), said clamping device (S) having a ramp (42) which can be rotated by a motor (51) and comprises a ramp track (41) extending along a helical line. The clamping device (S) additionally has a roller (40) which contacts the ramp track (41) and which is rotatably mounted in a carrier (31) connected to the plunger rod (25) so that when the ramp (42) is rotated along a first rotational direction (52), the ramp track (41) runs below the roller (40), which thus rotates, wherein the ramp track (41) is rotated for the clamping process such that the roller (40) runs on an ascending region (44) to a second plateau (45), and the plunger (26) is thereby moved into the rear end position of the plunger. For the dispensing process, the ramp track (41) is rotated on the basis of a contact between the roller (40) and the second plateau (45) until the roller (40) runs over a transition region (46) and accelerates towards the first plateau (43) on the basis of the pretension, and the plunger (26) is thereby moved towards an open dispensing end (14) of the cylinder (13). The ramp track (41) runs on the end face of a wall (85) extending along a circular path, wherein a cover (35) is provided which covers the ramp track (41), the carrier (31), and the roller (40), said cover having at least one scraper (80, 81, 82) which extends opposite the first direction and which extends within the wall (85) to the inner face (84) of the wall (85) and thus scrapes lubricant located on the inner face (84) from the inner face (84). |