Abstract: A foldable structure for a hospital bed contains two mounts, a bed frame, and a bed plane, each mount including two rotary positioning pieces, wherein each rotary positioning piece has a hole and an arcuate groove to axially connect the each rotary positioning piece with two coupling elements of the bed frame, such that the bed frame rotates relative to the two mounts, the each rotary positioning piece has two orifices corresponding to two ends of the arcuate groove so that a spring pin of each side of the bed frame is inserted into one of the two orifices of the each rotary positioning pieces, hence the spring pin is pushed out of the one of the two orifices of the each rotary positioning pieces, a coupling element in the arcuate groove rotates smoothly relative to a coupling element in the hole, thus retracting or expanding the bed frame easily.

Abstract: An iron club head includes a striking plate for striking a golf ball and a body. The body includes an elastically deformable thin wall. An opening is defined in a front side of the body and surrounded by the thin wall. The striking plate is bonded in the opening. The thin wall has a thickness smaller than that of the striking plate. When the iron club head hits a golf ball, a momentum of striking generated as a result of hitting the golf ball causes elastic deformation of the striking plate and the thin wall to increase an overall deformation of the iron club head.

Abstract: An improved structure for expandable bicycles to facilitate storing of a bicycle includes a cross bar which has one end fastened to the front fork of the bicycle and a sliding member slidable horizontally on the cross bar to alter the relative position of the front fork and the rear fork. The sliding member has a fastening member to fasten the head and seat of the bicycle on selected locations. Thus the bicycle may be extended as desired and stored conveniently.