Patent ID: 6262378
Filing Date: 2001-07-17
Classification: H01H

Abstract:
A rotary switch comprising:a housing defining a chamber and having a second central through hole, said housing forming on a first side a plurality of axially extending cams separated by grooves and spaced circumferentially around the second central through hole, and an axially extending ring coaxial to the second through hole and located near the periphery of said housing;a rotary dial forming a first central through hole, a cylindrical, binding member extending from a peripheral edge of said first through hole on a first side of said rotary dial, circular support projections peripherally and concentrically extending axially from the first side of the rotary dial and having a central groove so as to engage with said ring of said housing, and an indexing band frame extending from the first side and being tangential to said plurality of cams when said housing and said rotary dial are engaged;an indexing band comprising a central ridge, said indexing band being held by said indexing band frame and mounted so that said central ridge is operatively engageable with said plurality of cams on said housing for holding said rotary dial and;an operation shaft including an upper portion that extends upward through the binding member and the first through hole, and a lower portion having two diametrically opposed wing protrusions extending radially from a lower end of said operation shaft, said lower portion of said operation shaft forming a central axially extending recess for receiving a complementary resilient bushing;a contact plate having a central square shaped through hole and a plurality of contact protrusions axially extending in a predetermined sequence, wherein the lower portion of the operation shaft and said binding member slidably extend through said second through hole and said third through hole, said binding member being held in position with said contact plate so that said rotary dial and said contact plate are rigidly joined;a planar plate-shaped circuit board forming two grooves for receiving said two wing protrusions of said operation shaft, said circuit board having a contact member array operably engageable against said contact protrusions, a shaft contact portion arranged so as to engage with a lower end of said operation shaft, said shaft contact portion operating when pressed by the lower end of the operation shaft in accordance with axial movement of said operation shaft, wherein said housing connects to said circuit board so as to allow said rotary dial to rotate together with said contact plate, said housing and said circuit board being stationary independent of the axial movement of the rotary dial and the contact plate, said shaft contact portion and said contact member array being connected to a mutual terminal and a plurality of connecting terminals C1, C2, C3, C4, C5;wherein, as the rotary dial is rotated, the contact plate is rotated so that at least one contact protrusion is brought into electrical contact with a linear contact member of said contact member array, an output circuit being formed with said mutual terminal and said connecting terminals when said operating shaft is depressed, whereby rotation of said rotary dial is guided by the ring of the housing.