Slack adjuster

Claim 2

In a slack adjusting device comprising a pull rod having a threaded portion, a housing and an adjusting nut interconnecting said pull rod and said housing and having threads engaging said threaded portion, relative rotation between said nut and said rod being produced upon the application of a force to said rod directed longitudinally thereof thereby permitting relative movement of said rod and said housing longitudinally with respect to each other, and arresting means for arresting said relative rotation but permitting a predetermined amount of longitudinal relative movement of said rod and said housing when said relative rotation is arrested, the combination therewith of braking means in addition to said arresting means and actuated by at least one of said rod, said housing and said nut upon occurrence of said predetermined amount of relative movement for opposing said relative rotation between said rod and said nut, the force applied by said braking means to oppose said relative rotation being at least equal to 50 percent of the force required to prevent said relative rotation in the absence of said arresting means.

Claim 3

A slack adjusting device as set forth in claim 1, wherein said nut has a conical surface thereon which is movable in the direction of movement of said rod when said relative rotation is arrested and wherein said braking means comprises means secured to said housing and having a conical surface normally spaced from said conical surface on said nut but engageable and mating with said conical surface on said nut upon occurrence of said predetermined amount of relative movement.

Claim 4

A slack adjusting device as set forth in claim 2, wherein said force applied to said nut is at least equal to the force required to prevent said relative rotation in the absence of said arresting means.

Claim 5

A slack adjusting device as set forth in claim 3, further comprising spring means acting between said housing and said nut and urging said conical surface of said nut away from said conical surface of said means secured to said housing.

Claim 6

A slack adjusting device as set forth in claim 1, wherein said nut is rotatably mounted on said housing and is axially movable in a predetermined direction with respect to said housing by said predetermined amount of longitudinal relative movement, said nut is internally threaded, has ratchet teeth exteriorly thereof and has a circumferentially extending surface thereon facing in said predetermined direction, wherein said arresting means comprises a pawl on said housing engageable with said ratchet teeth and trigger means for causing said pawl to engage said ratchet teeth and arrest rotation of said nut with respect to said housing upon actuation of said trigger means and wherein said braking means comprises means non-rotatably secured to said housing and having A surface which complements said surface on said nut and which is normally spaced from the latter but is engageable therewith upon movement of said nut in said predetermined direction by said predetermined amount.

Claim 7

A slack adjusting device as set forth in claim 5, further comprising spring means acting between said housing and said nut and urging said surface on said nut away from said surface on said means non-rotatably secured to said housing.

Claim 8

A slack adjusting device as set forth in claim 6, wherein said surface on said nut and said surface on said means non-rotatably secured to said housing have the shape of truncated cones.

Claim 9

A slack adjusting device comprising a housing, an internally threaded adjusting nut rotatably mounted on said housing and movable axially in a predetermined direction by a predetermined amount with respect to said housing, said nut having a circumferentially extending, conical surface facing in said predetermined direction and having radially extending ratchet teeth on the periphery thereof, a pull rod having a threaded portion co-axial with said nut and engaging the threads of said nut, said nut being rotatable by said rod upon the application of a force thereto directed axially of said rod and thereby permitting movement of said rod with respect to said housing, a pawl mounted on said housing and engageable with said ratchet teeth, trigger means for controlling the position of said pawl and causing the latter to engage said ratchet teeth and arrest rotation of said nut upon actuation of said trigger means and upon movement of said rod in said predetermined direction, friction means mounted on said housing and having a conical surface complementary to the conical surface on said nut disposed in said predetermined direction with respect to said conical surface on said nut, the latter conical surface being engageable with the conical surface on said friction means upon movement of said nut in said predetermined direction by said predetermined amount, and spring means acting between said housing and said nut to urge said nut in a direction opposite to said predetermined direction whereby said nut is free to rotate with axial movement of said rod in said predetermined direction until said pawl engages said ratchet teeth and thereafter, with movement of said rod in said predetermined direction, said nut is moved by said rod in said predetermined direction causing said conical surface on said nut to engage said conical surface on said friction means and, by the friction therebetween, oppose rotation of said nut, the force applied to said nut by the friction between the conical surfaces to oppose rotation of said nut being at least equal to 50% of the force required to prevent rotation of said nut in the absence of engagement of said pawl with said ratchet teeth and with said nut in the position in which the conical surfaces are engaged.

Claim 10

A slack adjusting device comprising a housing, an internally threaded adjusting nut rotatably mounted on said housing and movable axially in a predetermined direction by a predetermined amount with respect to said housing, said nut having a circumferentially extending, conical surface facing in said predetermined direction and having radially extending ratchet teeth on the periphery thereof, a pull rod having a threaded portion co-axial with said nut and engaging the threads of said nut, said nut being rotatable by said rod upon the application of a force thereto directed axially of said rod and thereby permitting movement of said rod with respect to said housing, a pawl mounted on said housing and engageable with said ratchet teeth, trigger means for controlling the position of said pawl and causing the latter to engage said ratchet teeth and arrest rotation of said nut upon actuation of said trigger means and upon movement of said rod in said predetermined direction, friction means mounted on said housing and having a conical surface complementary to the conical surface on said nut disposed in said predetermined direction with respect to said conical surface on said nut, the latter conical surface being engageable with the conical surface on said friction means upon movement of said nut in said predetermined direction by said predetermined amount, and spring means acting between said housing and said nut to urge said nut in a direction opposite to said predetermined direction whereby said nut is free to rotate with axial movement of said rod in said predetermined direction until said pawl engages said ratchet teeth and thereafter, with movement of said rod in said predetermined direction, said nut is moved by said rod in said predetermined direction causing said conical surface on said nut to engage said conical surface on said friction means and, by the friction therebetween, oppose rotation of said nut, the force applied to said nut by the friction between the conical surfaces to oppose rotation of said nut being at least equal to 50% of the force required to prevent rotation of said nut in the absence of engagement of said pawl with said ratchet teeth and with said nut in the position in which the conical surfaces are engaged.

Claim 11

A slack adjusting device as set forth in claim 8, wherein said force applied to said nut by the conical surfaces is at least equal to the force required to prevent rotation of said nut in the absence of engagement of said pawl with said ratchet teeth and with said nut in said position.

Claim 12

A slack adjusting device as set forth in claim 8, further comprising a further pawl mounted on said housing and engageable with said ratchet teeth to prevent rotation of said nut in a direction opposite to that which it is rotated by movement of said rod in said predetermined direction, said trigger means controlling the position of said further pawl and causing it to engage said ratchet teeth when said trigger means is in its unactuated position.