UL1838
各位大侠：这个 “knockouts”是什么东东？见过的同学放张图片上来看看。
41 Tests on knockouts
41.1 A force of 10 lbs (4.5 kg) shall be applied to a knockout for 1 minute by means of a 1/4 in (6.4 mm)
diameter mandrel with a flat end. The force is to be applied in a direction perpendicular to the plane of the
knockout and at the point causing movement. The knockout shall remain in place and the clearance
between the knockout and the opening shall be no more than 0.063 in (1.6 mm) measured after the force
has been removed.
谢谢！:)
顶杆
解释：1.被打入某些物体中的薄壁管(如以后将灌入混凝土的管形钢柱)内的临时内支柱。2.一种用来顶出已成型工件的棒。3.穿入【金属】型腔背面的销杆,用以顶出制成件。4.早期来复枪枪管尾端中的细钢杆,弹丸由推弹杆撞入顶住钢杆并配合来复线塞紧。
一般遇到这种情况，在顶杆的末端会加一个弹性卡簧，且不易造成脱落 来个图你看看吧
灯具上Knock Out 常见于接线盒上，又叫预冲孔，敲一下会打开的，一般用于电管安装，如图：
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