| 摘要 |
A retractable mechanism for a writing element especially the expendable refill of a ball-point writing pen, is disclosed. A manually depressible plunger (4) advances a latch member (7) biased to retract the plunger (4). The latch member (7) has a pair of latch arms (11,12) one of which in an advanced or retracted position thereof engage a latch means (5,6). Depression of the plunger (4) releases the engaged latch arm (11 or 12) from its latch means (5,6). The resultant of the force on the plunger (4) and bias on the writing element (1) then laterally aligns the other latch arm (12 or 11) with its latch means (6 or 5). On release of the plunger (4), the bias on the writing element (1) brings a co-operating notch (16) and pivot edge (15) of the aligned latch arm (11,12) and latch means (5,6) into register for pivot action therebetween. This pivot action and rocking of the latch member (7) about its fulcrum (9) positions the latch member rearward limb (23) in readiness for the next depression of the plunger (14) whereby the writing element (1) may be displaced between its retracted and projected positions (or vice versa) in response to successive depressions of the plunger (4). |
