| 摘要 |
A pair of spaced apart gripping formations are located at an angle to each other, the gripping formations being operative to engage a pair of adjacent edges of a backing member meeting at a common corner in positions spaced from the common corner and also to engage sheet material superimposed on a front face of the backing member. A resilient locking element connects the two gripping formations and is arranged to extend along the rear of the backing member across the common corner in a position spaced therefrom, and a catch formation extends transversely from the locking element and is engageable and disengageable with a recess in the rear face of the backing member by displacement of the locking element in a direction transverse to the plane of the backing member, the locking element being operative resiliently to bias the catch formation towards engagement with the recess in the backing member. |
