# US 2018/0025857 A1 · Key device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0025857 A1 - Document ID: US20180025857A1 - Status: Published application - Kind: A1 - Application number: 15/367,375 - Filed: 2016-12-02 - Published: 2018-01-25 - Earliest claimed: 2016-07-20 - Assignees: Lite-On Electronics (Guangzhou) Limited; Lite-On Technology Corporation - Applicants: Lite-On Electronics (Guangzhou) Limited; Lite-On Technology Corporation - Inventors: MING-FU YEN - Web page: https://patentgrep.com/patent/US20180025857A1 ## CPC - H01H 3/125: {using a scissor mechanism as stabiliser} - H01H 3/122: {with enlarged actuating area, e.g. of the elongated bar-type; Stabilising means therefor} - H01H 13/705: characterised by construction, mounting or arrangement of operating parts, e.g. push-buttons or keys - H01H 2217/004: Larger or different actuating area - H01H 2221/058: to avoid tilting or skewing of contact area or actuator - H01H 2231/002: Calculator, computer - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) ## Abstract A key assembly including a base plate, a keycap, and at least one balance link. The balance link is disposed between the base plate and the keycap, the balance link having a top lever and two side levers, wherein the two side levers being connected to the top lever at both ends thereof, two ends of the two side levers away from the top lever being connected to the base plate, the top lever being connected to the keycap. The top lever and/or the two side levers include a plastic portion, the parts of the top lever and the two side levers other that the plastic portion being made of metal such that the balance link is a composite structure. The balance link contacts at least one of the keycap and the base plate via the plastic portion. ## Claims ### Claim 1 A key assembly, comprising: a base plate; a keycap; and at least one balance link located between the base plate and the keycap, the at least one balance link including a top lever and two side levers, wherein the two side levers are connected to both ends of the top lever respectively, the ends of the two side levers that are away from the top lever being connected to the base plate, and the top lever being connected to the keycap, wherein the top lever and/or the two side levers have a plastic portion, and the part of the top lever and the part of the two side levers other than the plastic portion are made of metal in such a manner that the at least one balance link is a composite structure, and wherein the at least one balance link is in contact with at least one of the keycap and the base plate via the plastic portion. ### Claim 2 (depends on 1) The key assembly according to claim 1, wherein the top lever includes at least one first pivot portion and the plastic portion that is formed into the at least one first pivot portion, and wherein the keycap includes at least one second pivot portion corresponding to the at least one first pivot portion, the at least one first pivot portion being pivotally connected to the at least one second pivot portion. ### Claim 3 (depends on 1) The key assembly according to claim 1, wherein the top lever includes a plurality of first pivot portions and the plastic portion that is formed into the first pivot portions, each first pivot portion including a cylindrical pivot shaft, in which the cylindrical pivot shafts are connected to each other, the top lever including a through hole located near each cylindrical pivot shaft, wherein the keycap includes a plurality of second pivot portions respectively corresponding to the first pivot portions, each second pivot portion including a support member and a pivot hole, the support member protruding from the keycap and corresponding to the through hole, the pivot hole being disposed in the support member and corresponding to the cylindrical pivot shafts, wherein each cylindrical pivot shaft is pivotally connected to each corresponding pivot hole of the second pivot portions, and each support member is received by each corresponding through hole of the top lever. ### Claim 4 (depends on 1) The key assembly according to claim 1, wherein the two side levers each include a slide-fit portion at the ends thereof that are away from the top lever, the two side levers including the plastic portion that is formed into the first slide-fit portions, and wherein the base plate includes two second slide-fit portions corresponding to the first slide-fit portions respectively in a manner such that the first slide-fit portions is slidably fitted to the second slide fit portions. ### Claim 5 (depends on 1) The key assembly according to claim 1, wherein the top lever has a reinforcing portion at the center part thereof. ### Claim 6 A balance link for a key assembly, the balance link comprising a top lever and two side levers, the two side levers being connected to both ends of the top lever respectively, wherein the top lever and/or the two side levers have a plastic portion, and the other parts of the top lever and the two side levers other than the plastic portion is made of metal in such a manner that the at least one balance link is a composite structure, and wherein the at least one balance link is in contact with at least one of a keycap and a base plate via the plastic portion. ### Claim 7 (depends on 6) The balance link for a key assembly according to claim 6, wherein the top lever includes at least one first pivot portion and the plastic portion that is formed into the at least one first pivot portion. ### Claim 8 (depends on 6) The balance link for a key assembly according to claim 6, wherein the top lever includes a plurality of first pivot portions, each first pivot portion including a cylindrical pivot shaft, in which the cylindrical pivot shafts are connected to each other, the top lever having a through hole located near each cylindrical pivot shaft. ### Claim 9 (depends on 6) The balance link for a key assembly according to claim 6, wherein the two side levers each include a slide-fit portion located at the ends thereof that are away from the top lever, the two side levers including the plastic portion that is formed into the first slide-fit portions. ### Claim 10 (depends on 6) The balance link for a key assembly according to claim 6, wherein the top lever has a reinforcing portion at the center part thereof.