Ladas & Parry
Fastener for form panels
 A fastening device to fasten at least two edge-to-edge contiguous panel facings includes a plurality of looped members projecting from the back face of each panel facing along the longitudinal sides thereof. Each looped member has an engagement face spaced parallely from the back face and two opposed angled flanks connected to the back face. Key members are to be inserted into the looped members, each having an insert rod portion and a handle rod portion which forms an angle with the insert rod portion, the insert rod portion having a pair of first opposed longitudinal faces, and a pair of second opposed longitudinal faces. The distance between the first opposed faces is smaller than the distance between the engagement face and the back face so that the insert rod portion can be inserted into two aligned looped members, and the distance between the second opposed faces is greater than the distance between the engagement face and the back face. The second opposed faces engage with the engagement face and the back face when the insert rod portion is turned an angle after being inserted. 
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inventional additional inventional inventional
Yuan-Ho
Lee