received by the International Bureau on 22 January 2014

1. A wiper motor drive system (28) comprising:

A motor (30), an output shaft (32) operatively connected to a wiper blade (26), and a breakaway clutch (34) operatively connected between said motor (30) and said output shaft (32);

said breakaway clutch (34) including a torque-sensitive releasable locking mechanism (52) having a first position (52A) wherein torque is translated from said motor (30) to said output shaft (32) through said breakaway clutch (34) to drive the wiper blade (26) across a surface to be wiped (20),

a second position (528) wherein torque is interrupted between said motor (30) and said output shaft (32) in response to a predetermined rotational torque differential acting on said output shaft. (32), said locking mechanism (52) being movable back to said first position (52A) when said differentia! torque is reduced on said output shaft (32);

and wherein said torque-sensitive releasable locking mechanism (52) further includes a groove (54) defined in said output shaft (32). a collar (56) disposed about said output shaft (32), said coliar (56) having a slot (58) aligned with said groove (54) of said output shaft (32) and being in driven, relationship with said motor (30), and a release member (60) disposed in said groove (54) of said shaft (32) and in said slot (58) of said collar (56), said release member (60) movable from said first position (52A) wherein torque is translated from said collar (56) to said output shaft (32) through said release member (60) and said second position (52B) wherein no torque is translated between said collar (56) and said output shaft (32).

2. The wiper motor drive system (28) as set forth in claim 1 , wherein said slot (58) of said collar (56) defines a pair of edges (62Λ, 62 B) disposed in spaced parallel relationship with respect to each other, said release member (60) has a cylindrical body which is carried in said groove (54) in releasable fashion and operatively engages each of said edges

(62A, 62B) of said slot (58) to thereby translate torque between said collar (56) and said output shaft (32).

3. The wiper motor drive system (28) as set forth in claim 2, wherein said groove (54) of said output shaft (32) has a concave profile.

4. The wiper motor drive system (28) as set forth in claim 1, wherein said torque- sensitive releasable locking mechanism (52) further includes a retaining mechanism (64; disposed about said collar (56) and movable between a first radial position (66 A) wherein said retaining mechanism (64) acts to keep said release member (60) disposed in said groove (54) of said output shaft (32), and a second radial position (66B) wherein said retaining mechanism (64) allows said release member (60) to move out of said groove (54) in response to a predetermined rotational torque differentia],

5. The wiper motor drive system (28) as set forth in claim 4, wherein said retaining mechanism (64 ) is a cylindrical ring having a gap (68) extending longitudinally substantially along the entire length of said retaining mechanism (64) such that said retaining mechanism (64) is movable from a first radial position (66A) to a second radial position (66B) in response to a predetermined radial force generated by said release member (60) as said release member (60) moves to said second position (52B).

6. The wiper motor drive system (28) as set forth in claim 4, wherein said output shaft (32) further includes a stop (70) operatively attached thereto and a washer (78) disposed between said stop (70) and said torque-sensitive releasable locking mechanism (52), such that said locking mechanism (52) is constrained longitudinally with respect to said output shaft (32) by said stop (70).

7. The wiper motor drive system (28) as set forth in claim 4, wherein said torque- sensitive releasable locking mechanism (52) furthef includes a gear (80) operatively attached to said collar (56), with said gear (80) being in driven relationship with said motor (30) so as to translate torque from said motor (30) to said collar (56).

8. The wiper motor drive system (28) as set forth in claim 7, wherein at least one of said gear (80) and said collar (56) has an alignment tab (84), and said retaining mechanism (64) has at least one alignment slot (86), with said alignment tab (84) being disposed in said alignment slot (86) such that said retaining mechanism (64) is substantially prevented from rotating with respect to said collar (56).

9. A wiper motor drive system (28) comprising:

a motor (30), a transmission (36) operatively connected to said motor (30), an output shaft (32) operatively connected to a wiper blade (26), and a breakaway clutch (34) operatively connected between said transmission (36) and said output shaft (32);

said breakaway clutch (34) including a torque-sensitive releasable locking mechanism (52) having a first position (52A) wherein torque is translated from said transmission (36) to said output shaft (32) through said breakaway clutch (34) to drive the wiper blade (26) across a surface to be wiped (20), a second position. (52B) wherein torque is interrupted between said transmission (36) and said output shaft (32) in response to a predetermined rotational torque differential acting on said output shaft (32), said locking mechanism (52) being movable back to said first position (52 A) when said differential torque is reduced on said output shaft (32); and

wherein said torque-sensitive releasable locking mechanism (52) further includes a groove (54) defined in said output shaft (32), a collar (56) disposed about said output shaft (32), said collar (56) having a slot (58) aligned with said groove (54) of said output shaft (32) and being in driven relationship with said transmission (36), and a release member (60) disposed in said groove (54) of said shaft (32) and in said slot (58) of said collar (56). said release member (60) movable from said first position (52A) wherein torque is translated from said collar (56) to said output shaft (32) through said release member (60) and said second position (52B) wherein no torque is translated between said collar (56) and said output shaft (32).

10. The wiper motor drive system (28) as set forth in claim 9, wherein said slot (58) of said collar (56) defines a pair of edges (62A, 62B) disposed in spaced parallel relationship with respect to each other, said release member (60) has a cylindrical body which is carried in said groove (54) in releasable fashion and operatively engages each of said edges (62A, 62B) of said slot (58) to thereby translate torque between said collar (56) and said output shaft (32).

1 1. The wiper motor drive system (28) as set forth in claim 10, wherein said groove (54) of said output shaft (32) has a concave profile.

12. The wiper motor drive system (28) as set forth in claim 9, wherein said torque - sensitive releasable locking mechanism (52) further includes a retaining mechanism (64) disposed about said collar (56) and movable between a first radial position (68A) wherein said retaining mechanism (64) acts to keep said release member (60) disposed in said groove (54) of said output shaft (32), and a second radial position (66B) wherein said retaining mechanism (64) allows said release member (60) to move out of said groove (54) in response to a predetermined rotational torque differential

13. The wiper motor drive system (28) as set forth in claim 32, wherein said retaining mechanism (64) is a cylindrical ring having a gap (68) extending longitudinally substantially along the entire length of said retaining mechanism (64) such that said retaining mechanism (64) is movable from a first radial position (66 A) to a second radial position (66B) in response to a predetermined radial force generated by said release member (60) as said release member (60) moves to said second position (52B).

14. The wiper motor drive system (28) as set forth in claim 12, wherein said output shaft (32) further includes a stop (70) operativeiy attached thereto and a washer (78) disposed between said stop (70) and said torque-sensitive releasable locking mechanism (52), such that said locking mechanism (52) is constrained longitudinally with respect to said output shaft (32) by said stop (70).

15. The wiper motor drive system (28) as set forth in claim 12, wherein said torque-sensitive releasable locking mechanism (52) further includes a gear (80) operatively attached to said collar (56). with said gear (80) being in driven relationship with said transmission (36) so as to translate torque from said transmission (36) to said collar (56).

16. The wiper motor drive system (28) as set forth in claim 15, wherein at least one of said gear (80) and said collar (56) has an alignment tab (84). and said retaining mechanism (64) has at least one alignment slot (86), with said alignment tab (84) being disposed in said alignment slot (86) such thai said retaining mechanism (64) is substantially prevented from rotating with respect to said collar (56).