Film fasteners for flexible sheets

Claim 1

A locking device for frictionally engaging a portion of a sheet of material and securing such sheet of material against movement under tension in such sheet, the device comprising a fixed channel member having a base and first, second and third generally upwardly extending, spaced apart, co-extensive walls, the first wall having a first upper portion spaced from the base and extending toward the second wall to form a deep recess along the base of the fixed channel member at one edge thereof, the second wall having a second upper portion forming a first rib based from the base and extending toward the first wall to provide a second recess along the base of the fixed channel member spaced from the first recess to define a channel shaped space between the first and second walls, and the third wall being along the edge of the channel opposite from the first wall and having an upper portion forming a second rib positioned above the base and extending in an outward direction away from the second wall; a removable member associated with the channel member including a lock bar and a connected cover member, the cover member being made of an elastomeric material, the lock bar being positionable between the first and second walls and the cover member connected to the lock bar being extendible over the second and third walls in a generally planar orientation between the second and third walls, and thereby overlying the receptacle formed between the second and third walls; said cover member having a lip portion at its outer edge extending along the cover member for engaging the second rib of the third wall; the lock bar being positioned between the first and second walls in use and having a first lock bar edge portion fitting into the first recess and having a first resilient lock bar wall portion extending upwardly from the first lock bar edge portion to fit against the upper portion of the first wall of the fixed channel member which faces the second wall thereof; said lock bar having a shoulder along a second edge portion thereof which fits under the first rib, and a second lock bar wall portion at the lock bar second edge which extends upwardly to position above the second wall of the fixed channel member, said cover member being attached to the second lock bar wall portion substantially along the length of the lock bar; the cover member being of size to be placed in tension in direction between the second and third walls of the fixed channel member to urge the shoulder on the second edge portion of the lock bar toward the first rib, a sheet to be fastened being positioned over the first wall of the fixed channel member, under the lock bar, over the second wall of the fixed channel member, and under the cover in the space between the second and third walls of the fixed channel member so that portions of such sheet extending between the second and third walls of the fixed channel member are hidden by the cover member, and such sheet being subjected to tension in a direction relative to the first wall of the channel member opposite from the position of the second wall, said lock bar thereby being urged under tension in such sheet and by the tension in the cover member to cause the shoulder of the lock bar to pinch such sheet against the first rib and the first resilient wall portion of the lock bar being lifted to pinch such sheet against the upper portion of the first wall of the fixed channel member, the main portion of a sheet which is held by the locking device extending in a direction away from the locking device without overlying the locking device.