| 摘要 |
<p>Knockout (22) circular shape is defined in enclosure (21) by circular groove (23) and has a cavity (27) extending in a generally radial directions and with a base surface inclined to the plane of knockout (22). Knockout (22) is attached to enclosure (21) by shearable material (26). The attachment between enclosure (21) and material (26) features sharp edge (24), while the attachment between knockout (22) and material (26) features arcuate edge 25. An operator employs tool (30) (e.g. a screwdriver blade) located by cavity (27), to apply force to the knockout (22) in order to tear material (26), detaching the knockout (22) from enclosure (21) and creating an aperture of a precise, predetermined size, suitable for insertion of a cable. The tear initiation point 40 corresponds with the comer of tool (30). Arcuate edge (25) serves to increase substantially the likelihood of shearable material (26) tearing near to sharp edge (24) when force is applied to knockout (22), thereby providing greater consistency in the dimensions and finish of the resulting aperture, by ensuring that material (26) is more resistant to shearing at arcuate edge (25).</p> |
