Timer switch assembly having escapement mechanism
OwnerWallace Leon Linninventor
Life of this patent
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Abstract
An escapement mechanism for an appliance timer includes a cylindrically shaped driving member which is concentric with the axis of the appliance timer program wheel. One or more cam lobes providing camming surfaces are formed on an interior cylindrical wall of the driving member. A ratchet wheel is disposed for rotation within the driving member. The ratchet wheel is drivingly connected to the program wheel. A pawl having a ratchet wheel engaging tooth at one end and a cam follower at the other end is actuated by the camming surfaces on the driving member to cause the pawl to move a predetermined distance in a first direction, engage the ratchet wheel, and then return the same distance in the opposite direction to advance the ratchet wheel and the program wheel in response to rotation of the driving member.
Claims9
In combination, a timer comprising a program wheel and an escapement mechanism for driving said program wheel, said escapement mechanism comprising a drive wheel rotatable about its axis and having a portion radially inwardly from its outer periphery defining a housing with an outer, generally cylindrical wall extending generally coaxially with said drive wheel, a ratchet wheel disposed for rotation on an output shaft, said ratchet wheel being disposed concentrically within said housing, a pawl for engaging said ratchet wheel, said pawl being disposed within said housing, means for providing a camming surface, said camming surface means projecting peripherally and radially inwardly toward said axis from said housing wall, means for following said camming surface, and means for urging said following means into contact with said camming surface, said following means being coupled to said pawl to move said pawl a distance determined by said camming surface in a first direction and to allow said pawl to engage said ratchet wheel and to return the same distance in a second and opposite direction to advance said ratchet wheel and output shaft a predetermined amount in response to rotation of said drive wheel, and said output shaft driving said program wheel.
A timer comprising an axially narrow program wheel defining an axis and an axially narrow escapement mechanism for driving said wheel, said timer comprising a housing having at least one wall, said mechanism comprising a coaxial output shaft, a generally-cylindrical drive wheel mounted in said housing for rotation about said axis, said drive wheel providing, at its outer periphery, an axially and peripherally extending wall, said drive wheel having an axial aperture therein for receiving said output shaft, a ratchet wheel attached to said output shaft, a camming surface formed interiorly of the wall of said drive wheel by at least one peripherally and radially inwardly extending cam lobe, a pawl having a proximal end formed to engage said ratchet wheel and a distal end providing a follower for engaging said camming surface, said pawl being generally arcuately shaped and disposed generally adjacent said wall of said drive wheel, and means for urging said follower into engagement with said camming surface, relative motion of said camming surface and said follower by rotation of said drive wheel actuating said pawl to move a predetermined distance in a first direction and said urging means causing said pawl to move the same distance in a second and opposite direction in engagement with said ratchet wheel to rotate said ratchet wheel and output shaft, said program wheel being drivingly connected to said output shaft.
Dependencies are inferred from the claim text.