EP0149338A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Windshield wiper transmission
Assignee: Motors Liquidation Co
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Filing: 1984-12-14
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Granted: —
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Expires: 2004-12-14
Abstract
Abstract @ A transmission (42) for a windshield wiper includes a non-circular pinion gear (86) having a closed pitch curve (89) with a basic elliptical segment (102) and a circular segment (108) and a non-circular output gear (90) having an open pitch curve (94) with a third order elliptical segment (110) and a circular segment (116). The pinion and the output gears (86,90) mesh such that the basic elliptical and third order elliptical pitch curve segments (102,110) roll against each other and the circular pitch curve segments (108,116) roll against each other so that the gear ratio of the combination varies sinusoidally through a first included angle of output gear rotation and remains substantially constant through a second included angle of output gear rotation.
Inventors
- 👤 Harry Charles Buchanan, Jr.
- 👤 William Richard Mack
- 👤 Jagmohan Krishan Malhotra
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 16:29
CPC Classifications
B; B60; B60S; B60S1/00; B60S1/02; B60S1/04; B60S1/06; B60S1/16; F; F16; F16H; F16H19/00; F16H19/001; F16H35/00; F16H2035/003; Y; Y10; Y10T; Y10T74/00; Y10T74/18; Y10T74/18856; Y10T74/1888; Y10T74/19; Y10T74/1987; Y10T74/19884
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
268 words
A windshield wiper transmission (42) mounted between a wiper assembly (30) pivotable through a wiping arc having an outer wipe limit (30') and an inner wipe limit (30") and through a secondary arc between said inner wipe limit (30") and a parked position (30"') and a constant speed, constant torque electric motor (38) having an armature shaft (48) rotatable in either direction through a first included angle corresponding to said wiping arc and through a second included angle corresponding to said secondary arc, characterised in that the transmission comprises: an output shaft (72) rotatable as a unit with said wiper assembly (30) about a first axis (69) of said transmission (42); a support shaft (54) rotatable about a second axis (57) of said transmission (42); fixed gear ratio gear means (48,52) between said motor (38) and said support shaft (54) operative to rotate the support shaft in directions and through included angles corresponding to the direction of rotation and included angles of said motor armature shaft (48); and variable gear ratio gear means (86,90) between said support shaft (54) and said output shaft (72) operative to rotate the output shaft and said wiper assembly (30) through said wiping arc during rotation of said motor armature shaft (48) through said first included angle, with said gear ratio varying sinusoidally from maximum at each of said inner and said outer wipe limits to minimum midway therebetween, and through said secondary arc during rotation of said motor armature shaft (48) through said second included angle, with said gear ratio remaining substantially constant at said maximum gear ratio throughout said secondary arc.
Claim 2
Dependent Claim
268 words
A windshield wiper transmission (42) mounted between a wiper assembly (30) pivotable through a wiping arc having an outer wipe limit (30') and an inner wipe limit (30") and through a secondary arc between said inner wipe limit (30") and a parked position (30"') and a constant speed, constant torque electric motor (38) having an armature shaft (48) rotatable in either direction through a first included angle corresponding to said wiping arc and through a second included angle corresponding to said secondary arc, characterised in that the transmission comprises: an output shaft (72) rotatable as a unit with said wiper assembly (30) about a first axis (69) of said transmission (42); a support shaft (54) rotatable about a second axis (57) of said transmission (42); fixed gear ratio gear means (48,52) between said motor (38) and said support shaft (54) operative to rotate the support shaft in directions and through included angles corresponding to the direction of rotation and included angles of said motor armature shaft (48); and variable gear ratio gear means (86,90) between said support shaft (54) and said output shaft (72) operative to rotate the output shaft and said wiper assembly (30) through said wiping arc during rotation of said motor armature shaft (48) through said first included angle, with said gear ratio varying sinusoidally from maximum at each of said inner and said outer wipe limits to minimum midway therebetween, and through said secondary arc during rotation of said motor armature shaft (48) through said second included angle, with said gear ratio remaining substantially constant at said maximum gear ratio throughout said secondary arc.
Claim 3
Dependent Claim
76 words
A windshield wiper transmission (42) according to claim 1, characterised in that said variable gear ratio gear means includes a pinion (86) rotatable with said support shaft (54) and defining a closed pitch curve (89) including a basic elliptical segment (102) and a circular segment (108), and an output gear (90) rotatable with said output shaft (72) and defining an open pitch curve (94) including a third order elliptical segment (110) and a circular segment (116).
Claim 4
Dependent Claim
259 words
A windshield wiper transmission (42) according to claim 1, characterised in that said first axis (69) is parallel to said second axis (57), the fixed gear ratio means comprises a worm shaft (48) rotatable by said motor (38), and a worm gear (52) rigidly attached to said support shaft (54) and engaging said worm shaft (48), and the variable gear ratio means comprises a non-circular pinion gear (86) rigidly attached to said support shaft (54) and defining a closed pitch curve (89) including a basic elliptical segment (102) and a circular segment (108), and a non-circular output gear (90) rigidly attached to said output shaft (72) and defining an open pitch curve (94) including a third order elliptical segment (110) and a circular segment (116), said pinion and said output gears (86,90) engaging together so that said basic elliptical pitch curve segment (102) rolls against said third order elliptical pitch curve segment (110) during rotation of said worm shaft (48) through said first included angle so that the gear ratio between said pinion gear (86) and said output gear (90) varies sinusoidally from a maximum at each of said inner and said outer wipe limits to a minimum midway therebetween, and so that said pinion pitch curve circular segment (108) rolls against said output gear pitch curve circular segment (116) during rotation of said worm shaft (48) through said second included angle so that the gear ratio between said pinion gear (86) and said output gear (90) remains substantially constant at said maximum gear ratio throughout said secondary arc.
References Cited (Backward Citations)
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