| 摘要 |
<p>The invention relates to a scissor jack (1) comprising four arms (4) hingedly arranged to provide two opposite elbows (5,6) between a base (2) and a load support (3). A first collar (15) provided at one of the elbows supports a ball screw assembly (19) in engagement with threads on the shaft (18). The jack (1) includes a brake mechanism (51) to resist rotation of the shaft (18). The ball screw assembly (19) has a cylindrical body (20) housed at least partly within the first collar (15) and a flange (21) that is secured against a face (22) on an outer side of the first collar (15). The other elbow has a second collar (16) located over the journal on the shaft (18). The second collar (16) supports a mounting bracket (30) for a planetary gearbox (31). Trunnions (7, 8) with screw-threaded spigots (27) at their inner ends engage in screw-threaded holes (26) in either side of the first and second collars (15, 16). The trunnions (7, 8) each have a journal (28), which locates in corresponding openings (14) at the elbows (5, 6) of the arms (4) and a head (29) at its outer end which locates against the arm (4).</p> |
