Patent ID: 7784159

Claim:
A spring fastener comprising: a first side and a second side opposite the first side, the first side connected to the second side thereby forming a U-shaped structure, a bottom portion wherein the first side and the second side are connected, a first engagement spring, connected to the first side in the vicinity of the bottom portion, the second side comprising second barbs having second front ends, and a second engagement spring, connected to the second side in the vicinity of the bottom portion, each of the first and second engagement springs having a substantially flat engagement region with a hindrance portion, the hindrance portion comprising one to three ripples, each ripple having the form of a depression on said hindrance portion, the depression having a deepest part, a front side, a back side and a width, and the hindrance portion having a surface, wherein the depth of each ripple is the distance between the surface of the hindrance portion and the deepest part of the respective ripple, thereby resulting in the hindrance portion having a non-uniform thickness, wherein at least one barb is cut from its respective side, flexible, and bent at its respective front end.