A composite coil spring includes a coil body that extends along a coiled axis. The coil body includes a core and fiber layers impregnated with a polymer material. The fiber layers are arranged around the core at different radial distances from the coiled axis. Each fiber layer extend around the coiled axis at an oblique fiber angle to the coiled axis. The fiber layers include at least one glass fiber layer and at least one carbon fiber layer. Each fiber layer includes a number of fibers that is a product of a common base number of fibers multiplied by a positive non-zero integer from a set of positive non-zero integers. The positive non-zero integer of at least one of the fiber layers is different from the positive non-zero integer of at least one other of the fiber layers.

A composite coil spring includes a coil body that has a core and fiber layers impregnated with a polymer material. The fiber layers are wound around the core. The fiber layers extend around the coiled axis at oblique fiber angles. Each of the fiber layers includes a number of fibers that is a product of a common base number of fibers multiplied by a positive non-zero integer from a set of positive non-zero integers from 1 to 20. The positive non-zero integer of at least one of the fiber layers is different from the positive non-zero integer of at least one other of the fiber layers. At least one of the fibers layers is glass fibers and another of the fiber layers is carbon fibers, and each of an innermost fiber layer and an outmost fiber layer of the fiber layers is independently selected from glass fibers and carbon fibers.

A composite coil spring includes a coil body that has a core and fiber layers impregnated with a polymer material. The fiber layers are wound around the core. The fiber layers extend around the coiled axis at oblique fiber angles. Each of the fiber layers includes a number of fibers that is a product of a common base number of fibers multiplied by a positive non-zero integer from a set of positive non-zero integers from 1 to 20. The positive non-zero integer of at least one of the fiber layers is different from the positive non-zero integer of at least one other of the fiber layers. At least one of the fibers layers is glass fibers and another of the fiber layers is carbon fibers, and each of an innermost fiber layer and an outmost fiber layer of the fiber layers is independently selected from glass fibers and carbon fibers.

A composite coil spring (20) includes a coil body (2) that extends along a coiled axis (24). The coil body includes a core (38) and a plurality of fiber layers (32) impregnated with a polymer material. The plurality of fiber layers are arranged around the core at different radial distances from the coiled axis. Each of the plurality of fiber layers extends around the coiled axis at an oblique fiber angle to the coiled axis. Each of the plurality of fiber layers includes a number of fibers that is a product of a common base number of fibers multiplied by a positive non-zero integer from a set of positive non-zero integers. The positive non-zero integer of at least one of the plurality of fiber layers is different from the positive non-zero integer of at least one other of the plurality of fiber layers.

Various embodiments of the present technology may provide methods and apparatus for a 3D-printed spring. The 3D-printed spring may be formed from a plurality of toroidal elements spaced apart from each other and connected with a plurality of connectors. Each connector connects one toroidal element to a directly adjacent toroidal element.

A torsion spring may be configured as a torsion bar or a helical spring made of a spring wire made of fiber-composite material. The torsion spring may have a plurality of layers of fiber reinforcement that have been saturated with a matrix material, wherein the layers may have fibers that are tension-loaded and fibers that are compression-loaded. The at least one compression-loaded group may have a lower group stiffness than the tension-loaded group with the highest group stiffness. Methods for designing or making torsion springs made of fiber-composite material are also disclosed.

A torsion spring may be formed as a bar spring or helical spring comprising a spring wire of fiber composite material. In some examples, the torsion spring comprises a number of layers of fiber reinforcement, which are impregnated with a matrix material. The layers may comprise tensile-loaded fibers and compression-loaded fibers. Groups of layers of the same loading direction may exist and, seen from an inside to an outside, the group stiffness of at least two groups may differ. Likewise, methods for making such torsion springs of fiber composite material are disclosed.

A pocketed spring assembly comprises parallel strings, each string joined to at least one adjacent string. At least some of the strings have springs of different gauge wire and some of the pockets of the strings having springs of different gauge wire are spliced together. At least some of the strings have springs of different geometries and some of the pockets of the strings having springs of different geometries are spliced together. At least some strings may have end sections with springs different than a middle section therebetween, the springs of the end sections being firmer than the springs of the middle section.