Parking brake releasing mechanism

Claim 2

A parking brake release mechanism for use in association with a parking brake actuator member having a toothed quadrant disposed on a part thereof and movable between a brake applied and brake release position, said release mechanism comprising: a pawl which is engaged with said toothed quadrant for restraining the movement of said actuator member to its brake release position; a first stationary member rotatably supporting said pawl about a first axis; a first lever secured to said pawl and integrally rotatable with said pawl, said first lever having an intermediate portion terminating in a free end remote from said first axis; a second stationary member; a second lever pivotally coupled to said second stationary member for rotation about a second axis and having an intermediate portion terminating in a free end remote from said second axis, said free end of the first lever abutting the intermediate portion of said second lever at a first substantially single point of contact to maintain a lever ratio of the mechanism at one level while said pawl is engaged with said quadrant; means for imparting rotative force to said second lever to cause the intermediate portion of said second lever to move against the free end of said first lever solely at said first point of contact and rotate while maintaining said first point of contact to cause rotational movement of said first lever to disengage said pawl from said quadrant, said first lever being spaced from said second lever such that said first lever only contacts said second lever by engagement of said free end of said first lever abutting the intermediate portion of said second lever at said first point of contact during rotation of said first and second levers until disengagement of said pawl from said quadrant whereupon said free end of said second lever contacts said first lever solely at the intermediate portion of said first lever at a second substantially single point of contact to thereby effect a sudden decrease in lever ratio to a level lower than said one level upon further rotation of said second lever.

Claim 3

A mechanism in accordance with claim 1, wherein said first lever is of S letter shape.

Claim 4

A mechanism in accordance with claim 1, wherein said first lever is a straight bar-like member.

Claim 5

A mechanism in accordance with claim 1, wherein said pawl and said first lever are integrally manufactured.

Claim 6

A mechanism in accordance with claim 1, wherein said pawl and said first lever are separately manufactured for being connected together by a pin to be pivotally supported by said first stationary member.

Claim 7

A mechanism in accordance with claim 1, wherein said means for imparting rotative force to said second lever is a partly bent rod, which is slidingly movable by means of drawing with a knob, pivotally connected to said second lever.

Claim 8

A mechanism in accordance with claim 1, wherein said means for imparting rotative force to said second lever is a rotatable lever directly secured to said second lever.

Claim 9

A mechanism in accordance with claim 1, wherein said parking brake actuator member is a pedal which is rotatable about a third axis and is provided with said quadrant on an arcuate upper end thereof.

Claim 10

A mechanism in accordance with claim 8, wherein said first lever is disposed in a plane separate from and parallel to the plane in which said pedal is rotated.

Claim 11

A mechanism in accordance with claim 8, wherein said quadrant is disposed on a part of said pedal.

Claim 12

A mechanism in accordance with claim 1 wherein said actuator member is connected to a pedal and movable in a straight line direction in response to pedal movement.

Claim 13

A release mechanism for releasing a parking brake including an actuator member operated to apply a parking brake and having a toothed portion for locking the actuator member in a selected position, which comprises: a pawl supported pivotally about a first axis adjacent said toothed portion and engageable with the toothed portion; a first lever coupled to said pawl for pivotally moving said pawl about said first axis and having an intermediate portion and an end portion coupled to said intermediate portion; a second lever supported at one end thereof pivotally about a second axis and having an intermediate portion and an end portion coupled to the intermediate portion of said second lever; and a release member coupled to said second lever to pivot said second lever about said second axis and into contact with said first lever end portion at a first substantially single point of contact and rotate said second lever while maintaining said single point of contact, said intermediate portion of the second lever abutting the end portion of the first lever at said first substantially single point of contact during an initial pivotal motion of the second lever by said release member to rotate said first lever while maintaining said single point of contact until said pawl has been pivoted away from said toothed portion, said first and second levers being spaced from one another such that said first lever engages said second lever solely by the contact of said first lever end portion with the intermediate portion of said second lever at said first point of contact during rotation of said first and second levers until said pawl has been pivoted away from said toothed portion, whereupon said end portion of the second lever abuts the intermediate portion of the first lever at a second substantially single point of contact upon disengagement of said pawl from said toothed portion, said abutment of the end portion of the second lever with the intermediate portion of the first lever at said second point of contact effecting a sudden decrease in the lever ratio of the mechanism from one distinct ratio to another distinct ratio to thereby decrease a required force appled to said release member during said initial pivotal motion and decrease a required operation stroke of the release member during a following pivotal motion of the second lever by the release member after said disengagement of the pawl.

Claim 14

A release mechanism for releasing a parking brake including an actuator member operated to apply a parking brake and having a toothed portion for locking the actuator member in a selected position, which comprises: a pawl supported pivotally about a first axis adjacent said toothed portion and engageable with the toothed portion; a first lever coupled to said pawl for pivotally moving said pawl about said first axis and having an intermediate portion and an end portion coupled to said intermediate portion; a second lever supported at one end thereof pivotally about a second axis and having an intermediate portion and an end portion coupled to the intermediate portion of said second lever; and a release member coupled to said second lever to pivot said second lever about said second axis and into contact with said first lever end portion at a first substantially single point of contact and rotate said second lever while maintaining said single point of contact, said intermediate portion of the second lever abutting the end portion of the first lever at said first substantially single point of contact during an initial pivotal motion of the second lever by said release member to rotate said first lever while maintaining said single point of contact until said pawl has been pivoted away from said toothed portion, said first and second levers being spaced from one another such that said first lever engages said second lever solely by the contact of said first lever end portion with the intermediate portion of said second lever at said first point of contact during rotation of said first and second levers until said pawl has been pivoted away from said toothed portion, whereupon said end portion of the second lever abuts the intermediate portion of the first lever at a second substantially single point of contact upon disengagement of said pawl from said toothed portion, said abutment of the end portion of the second lever with the intermediate portion of the first lever at said second point of contact effecting a sudden decrease in the lever ratio of the mechanism from one distinct ratio to another distinct ratio to thereby decrease a required force appled to said release member during said initial pivotal motion and decrease a required operation stroke of the release member during a following pivotal motion of the second lever by the release member after said disengagement of the pawl.

Claim 15

A release mechanism in accordance with claim 12, wherein said actuator member comprises a brake pedal pivotable about a third axis and having said toothed portion along an arcuate periphery at one end thereof located adjacent said pawl.

Claim 16

A release mechanism in accordance with claim 13, wherein said first lever is disposed in a plane separate and parallel to the plane in which said pedal is rotated.

Claim 17

A release mechanism in accordance with claim 12, wherein said first lever is pivoted about said first axis.

Claim 18

A release mechanism in accordance with claim 12, wherein said release member comprises a rod slidably supported and having a bent portion pivotally coupled to the second lever.

Claim 19

A release mechanism in accordance with claim 12, wherein said pawl and said first lever comprise a single integral lever of generally S-letter shape having a free end forming the end portion which is turned toward the intermediate portion of said second lever, and the intermediate portion of the second lever has a straight surface abutting said free end of said first lever during said initial pivotal motion of the second lever.

Claim 20

A release mechanism comprising: a first member having an engaging end and an intermediate portion coupling said engaging end to a free end; means for rotatably supporting said first member; a second member having an intermediate portion coupled to a free end; means for rotatably mounting said second member; and means for moving the intermediate portion of said second member into contact with the free end of said first member at a first substantially single point of contact and rotate said second member while maintaining said first point of contact to cause rotational movement of said first member, said first and second members being cosntructed and arranged such that said first and second members engage one another solely by said contact of the intermediate portion of said second member with the free end of said first member at said first point of contact during rotation of said first and second members to produce a first distinct lever ratio until such time as further rotational movement causes the free end of said second member to contact the intermediate portion of said first member at a second substantially single point of contact and decrease said lever ratio from said one distinct ratio to another distinct ratio.

Claim 21

A release mechanism comprising: a first member having an engaging end and an intermediate portion coupling said engaging end to a free end; means for rotatably supporting said first member; a second member having an intermediate portion coupled to a free end; means for rotatably mounting said second member; and means for moving the intermediate portion of said second member into contact with the free end of said first member at a first substantially single point of contact and rotate said second member while maintaining said first point of contact to cause rotational movement of said first member, said first and second members being cosntructed and arranged such that said first and second members engage one another solely by said contact of the intermediate portion of said second member with the free end of said first member at said first point of contact during rotation of said first and second members to produce a first distinct lever ratio until such time as further rotational movement causes the free end of said second member to contact the intermediate portion of said first member at a second substantially single point of contact and decrease said lever ratio from said one distinct ratio to another distinct ratio.