A screening, crushing or mixing bucket is formed into a bucket of an excavating machine or bucket loader. The lamp assembly includes a lamp casing having elastic tongues at both sides thereof and mounted with a lamp therein, and a transparent cover having locking depressions at both sides thereof and inserted into the lamp casing. The sheath is made of a compliant or partially compliant material, including latex, vinyl, natural and synthetic rubbers, silicone, nylon, polyethylene, polypropylene, and non-degradable or degradable elastomers. A flexible, elongate support element is secured between each of the clips and the respective end portions of the support tube.