Brake apparatus and plural and independent actuators therefor

Claim 2

A brake apparatus for motor vehicles comprising a rotatable brake drum having a friction surface, a stationary backing plate, a pair of brake shoes mounted on said backing plate and arranged adjacent said friction surface of said brake drum, an actuating means positioned between only a first opposed ends of each of said brake shoes for selectively moving said first ends into contact with said friction surface, and mechanical expanding means for selectively moving the other opposed ends of said brake shoes and said first opposed ends of said brake shoes into contact with said friction surface and maintaining said contact, by all four of said ends of said shoes, said mechanical expanding means comprising a link and toggle means for expanding said other opposed ends and for simultaneously expanding said first opposed ends, the braking caused by said mechanical expanding means being stronger than the braking caused by said actuating means.

Claim 3

A brake apparatus as claimed in claim 1, wherein said actuating means is slidably mounted relative to said backing plate and forms part of said link and toggle means.

Claim 4

A brake apparatus as claimed in claim 1, wherein said actuating means is mounted on said backing plate and comprises a cylinder enclosing a pair of pistons forming a part of said link and toggle means.

Claim 5

A brake apparatus as claimed in claim 1, wherein said link and toggle means includes a floating anchor positioned between said brake shoes in parallel with said actuating means.

Claim 6

A brake apparatus as claimed in claim 4, wherein said floating anchor is adapted to regulate the clearance between said brake drum and said brake shoes.

Claim 7

A brake apparatus as claimed in claim 1, further comprising a rigid member mounted on said backing plate and having said other opposed ends of said brake shoes rockably and slidably connected thereto for serving as an anchor; and wherein a portion of said link and toggle means is arranged between said first opposed ends of said brake shoes for serving as a floating anchor; the arrangement being such that one of said other opposed ends of said brake shoes acts as an anchor when said mechanical expanding means is actuated.

Claim 8

A brake apparatus for motor vehicles as in claim 6, wherein one part of said link and toggle means is arranged in the vicinity of said rigid member and adapted for expanding the opposed ends of the brake shoes on the side of said rigid member, and a second part of said link and toggle means is disposed on the side of said actuating means, the arrangement being such that the input on said link and toggle means adjacent said rigid member is transmitted to an actuating member part of said link and toggle means, so that the opposed ends of said brake shoes beside said rigid member engage with said brake drum, yet the opposed ends of said brake shoes on the side of said actuating means are capable of further expansion.

Claim 9

A brake apparatus for motor vehicles as claimed in claim 6, wherein said mechanical expanding means comprises a first actuating lever having an L-shape and which is manually operable at its one end and the other end thereof is in contact with one of said brake shoes, a second actuating lever pivotally mounted at its one end on an intermediate portion of said first lever, and a third actuating lever having an L-shape and connected to the other end of said second lever and pivotally mounted on the other brake shoe at the side of said other opposed ends thereof for transmitting force to expand said first opposed ends of said brake shoes.

Claim 10

A brake apparatus as claimed in claim 1, further comprising a rigid member mounted on said backing plate and having said other opposed ends of said brake shoes rockably and slidably connected thereto for serving as an anchor; and wherein said actuating means includes a fixed cylinder enclosing a pair of pistons arranged in a manner to prevent movement of one of said pistons from being transmitted to the other of said pistons; and said link and toggle means includes a pair of force transmitting members operatively connected to said brake shoes, respectively, whereby said first opposed ends of said shoes are moved into contact with said friction surface through said force transmitting members even if said other opposed ends have been moved into contact with said friction surface; the arrangement being such that diagonally positioned two ends of said brake shoes act as anchor means during the braking caused by said mechanical expanding means thereby creating the braking of said mechanical expanding means which is stronger than the braking caused by said actuating means.

Claim 11

A brake apparatus for motor vehicles as claimed in claim 9, wherein said force transmitting members are comprised of a pair of link means which are symmetrically disposed on each brake shoe.

Claim 12

A brake apparatus for motor vehicles as claimed in claim 9, wherein said mechanical expanding means comprises a first actuating lever having an L-shape and which is manually operable at its one end, a second actuating lever pivotally mounted at its one end on the intermediate portion of said first lever, a pair of third actuating levers pivotally mounted on each of said brake shoes at the side of said second opposed ends thereof and each kept in contact at one end thereof with the other ends of said first and second actuating levers, each other end of said third actuating levers being pivoted to one end of said force transmitting members, and a pair of fourth actuating levers pivotally mounted on each of said brake shoes at the side of said first opposed ends thereof and each kept in contact at one end thereof with the other ends of said force transmitting members, the other end of each fourth actuating lever being kept in contact with said actuating means.