clapper（n.）
13世纪晚期，"发出响亮、尖锐的声音的东西"，这是从 clap (v.)派生出的名词。"钟舌"的含义始于14世纪晚期。古英语中有 clipur。"在开始拍摄电影时，用于同步画面和声音的镜头前方的铰接板"的含义始于1940年。
Clappering.—It is still necessary to warn clergymen and churchwardens against allowing the lazy and pernicious practice of 'clappering,' i.e. tying the bell-rope to the clapper, and pulling it instead of the bell. More bells have been cracked in that way than by all other causes together, and there is not the least excuse for it .... [Sir Edmund Beckett, "A Rudimentary Treatise on Clocks and Watches and Bells," London, 1883]
敲击。—仍然有必要警告牧师和教堂管理员，不要允许那种懒散和有害的'敲击'习惯，即 i.e. 将铃绳系在铃舌上，而不是拉铃。这种方式导致的铃声裂纹比所有其他原因加起来还要多，对此没有任何借口.... [埃德蒙·贝克特爵士，《钟表和钟的初级论文》，伦敦，1883年]
该词起源时间：13世纪末