Hardware spring is metal spring. According to the mechanical properties, hardware spring can be divided into tension spring, compression spring, torsion spring and bending spring. According to the shape, hardware spring can be divided into disc spring, ring spring, plate spring, spiral spring, truncated cone scroll spring and torsion bar spring. According to the manufacturing process, hardware spring can be divided into cold coil spring and hot coil spring. Because of its simple manufacture, various types of springs can be made according to the loading conditions, and its structure is simple, so it has the widest application range and the largest number of uses.
We can do an experiment. 1. Stick a piece of white paper on the bottom plate to calibrate the scale. When there is no heavy object on the hook, the position of the pointer shall be set to zero scale, and then hang 1n, 2n, 3N, 4N, 5N and other hook codes on the hook in turn. Hang one hook code for each h, and mark the scale at the pointer. 2. Divide the distance between scales properly. Take a board of 310x80x5mm as the base plate, and nail a small board of 80x15x5mm on the upper end. In the center of the small board is a sheep eye ring as a lifting ring. One end of the spring is welded on the lifting ring, and the other end is welded with a piece of wire with a diameter of 2.5mm and a length of 150 mm. A hook is arranged at the lower end of the iron wire, and a thin iron plate is installed at the welding part between the upper end and the spring as the pointer. The pointer shall be perpendicular to the iron wire, and the position on the wire can be adjusted. Install a small iron wire frame bent into a semicircle on the bottom plate, and frame the iron hook to prevent the iron hook from swinging left and right.
Since the stiffness coefficient is defined as the total force divided by the total displacement, since the total displacement of two series springs is larger than the original one, the corresponding stiffness coefficient becomes smaller. In the case of parallel connection, it is just the opposite: the total force is and, and the total displacement is constant, so the stiffness coefficient of the spring system in series becomes larger. Let the elastic coefficients of the two springs be KL, K2 (and the original length of the spring is the same), but the elongation of the two springs is the same while the tension of the two springs is different. The total tension of the two sides of the parallel discerning group is the sum of the tension of the two springs. According to this relationship, we can get: T = (KL + K2) △ x, so the equivalent elastic coefficient K is KL + K2