# US 4,398,741 A · Anti-nose-dive apparatus of a motorcycle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,398,741 A - Document ID: US4398741A - Status: Granted - Kind: A - Application number: 06/333,485 - Filed: 1981-12-22 - Granted: 1983-08-16 - Earliest claimed: 1980-12-22 - Assignees: Kawasaki Jukogyo Kabushiki Kaisha - Inventors: Kinuo Hiramatsu - Web page: https://patentgrep.com/patent/US4398741A ## CPC - B62K 25/04: for mounting axles resiliently on cycle frame or fork (for sidecars, forecars or the like B62K27/06) - B62K: CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDECARS, FORECARS, OR THE LIKE ## Abstract This disclosure relates to apparatus for preventing the nose dive produced when a motorcycle is sharply braked. The motor cycle includes a frame, front and rear wheels, and front and rear mounting means for connecting the wheels to the frame. The anti-nose-dive apparatus includes a generally U-shaped torsion bar having a center portion and front and rear arms. The center portion is rotatably mounted on the frame, the front arm is connected to the front mounting means, and the rear arm is connected to the rear mounting means. When the vehicle is moving and is sharply braked, the front end of the frame tends to move down relative to the front wheel. This action twists the torsion bar causing the rear mounting means to tend to rise. The reaction on the torsion bar causes the rear end of the frame to move down relative to the rear wheel, thereby reducing the amount of the nose dive. ## Claims ### Claim 1 An anti-nose-dive apparatus for a motorcycle having a frame, front and rear wheels both movable in a generally vertical direction relative to said frame, and front and rear mounting members respectively connected to and movable with said front and rear wheels and connecting said wheels to said frame, said apparatus comprising a torsion bar extending generally in the direction of travel of said motorcycle and adapted to be journaled on said frame, said torsion bar terminating in front and rear arms which extend generally in the same lateral direction, first means adapted to pivotally interconnect said front arm with said front mounting member so that relative vertical movement between said frame and said front wheel rotates said torsion bar, and second means adapted to pivotally interconnect said rear arm with said rear mounting member so that said rotation of said torsion bar moves said frame relative to said rear wheel. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein said front arm includes an elongated plate part which is rotatable relative to the remainder of said torsion bar to thereby change the plane of said plate part. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein said motorcycle further includes a braking cylinder, and said apparatus includes third means adapted to connect the braking cylinder with said front arm for rotating said front arm when the cylinder produces braking pressure for said motorcycle. ### Claim 4 (depends on 1, 2, 3) The apparatus of any one of claims 1, 2 or 3, wherein said motorcycle further includes a front fork axially fixed to said frame and including a pair of bottom sleeves which are movable relative to said frame and which carry said front wheel, and a pair of swing arms which pivot on said frame and carry said rear wheel, said first means being connected to at least one of said bottom sleeves, and said second means being connected to at least one of said swing arms. ### Claim 5 (depends on 1, 2, 3) The apparatus of any one of claims 1, 2 and 3, wherein the motorcycle further includes shock absorbers connected between said frame and said rear mounting means. ### Claim 6 A motorcycle including anti-nose-dive apparatus, comprising a frame, front and rear wheels, front and rear mounting means connecting said front and rear wheels to said frame, a generally U-shaped torsion bar including a center portion and front and rear arm portions, said center portion extending lengthwise of said frame and rotatably attached to said frame, first means connecting said front arm to said front mounting means, and second means connecting said rear arm to said rear mounting means. ### Claim 7 (depends on 6) Apparatus according to claim 6, wherein said rear mounting means includes a shock absorber. ### Claim 8 (depends on 6, 7) Apparatus according to claim 6 or 7, wherein said front mounting means comprises a shock absorber including a cylinder attached to said front wheel and a rod attached to said frame, said front arm being connected to said cylinder. ### Claim 9 (depends on 6) Apparatus according to claim 6, wherein said front arm is adjustable between a highly rigid position and a relatively flexible position.