Image Number 4 for United States Patent #4273047.
Disclosed is a method and apparatus for attaching shaped charge units into a well perforating gun. The shaped charge unit has an ear shaped extension having a cavity for receiving a wire in the perforating assembly. A second extension is positioned on the perforating charge unit having a threaded hole for containing a screw which may be advanced into tight engagement with the wire in the cavity of the first extension. This arrangement allows perforating units to be quickly added or taken out of a perforating gun assembly by adjustment of the screws through the threaded assemblies of the perforating charges.