Lash adjuster

Abstract

A lash adjuster is provided of which the adjusting screw can be repeatedly and easily brought into the initial set position. In a lash adjuster including a nut member 14 having an internal thread 20 on the inner periphery thereof, an adjusting screw 15 having an external thread 19 on the outer periphery thereof that is in threaded engagement with the internal thread 20, and a return spring 17 biasing the adjusting screw 15 in the direction to protrude from the nut member 14, a washer 18 is provided which is axially deformed and produces frictional resistance to rotation that serves to prevent rotation of the adjusting screw 15 by its elastic restoring force when the adjusting screw 15 is threaded into the nut member 14.

1 . A lash adjuster comprising:
 a nut member ( 14 ) having an internal thread ( 20 ) on an inner periphery thereof:   an adjusting screw ( 15 ) having an external thread ( 19 ) formed on an outer periphery thereof and in threaded engagement with the internal thread ( 20 );   a return spring ( 17 ) biasing the adjusting screw ( 15 ) in a direction to protrude from the nut member ( 14 ); and   an initial setting means ( 18 ) configured to be deformed in an axial direction when the adjusting screw ( 15 ) is threaded into the nut member ( 14 ), thereby producing frictional resistance to rotation that tends to prevent rotation of the adjusting screw ( 15 ) due to an elastic restoring force of the initial setting means ( 18 ).   
     
     
         2 . The lash adjuster of  claim 1  wherein said initial setting means ( 18 ) produces said elastic restoring force so as to be symmetrical with respect to the axis. 
     
     
         3 . The lash adjuster of  claim 1  wherein said initial setting means ( 18 ) is an elastic member located so as to oppose an end of the adjusting screw ( 15 ) that is inserted in the nut member ( 14 ). 
     
     
         4 . The lash adjuster of  claim 3  wherein said elastic member is a washer ( 18 ) comprising an annular sheet having circumferentially extending spring pieces ( 26 ) formed by cutting and raising portions of the annular sheet. 
     
     
         5 . The lash adjuster of  claim 4  wherein said spring pieces ( 26 ) are cut and raised in a direction to bias the adjusting screw ( 15 ) in a loosening direction. 
     
     
         6 . The lash adjuster of  claim 5  wherein said washer ( 18 ) is formed by pressing spring steel. 
     
     
         7 . The lash adjuster of  claim 3  wherein said elastic member is a toothed washer ( 28 ) comprising an annular sheet and teeth radially extending from the annular sheet. 
     
     
         8 . The lash adjuster of  claim 7  wherein the teeth ( 27 ) of the toothed washer ( 28 ) are twisted in a direction to bias the adjusting screw ( 15 ) in a loosening direction. 
     
     
         9 . The lash adjuster of  claim 8  wherein said toothed washer ( 28 ) is formed by pressing spring steel. 
     
     
         10 . The lash adjuster of  claim 3  wherein said elastic member is a conical spring washer. 
     
     
         11 . The lash adjuster of  claim 3  wherein said elastic member is a corrugated spring washer. 
     
     
         12 . The lash adjuster of  claim 3  wherein said elastic member is a spring washer. 
     
     
         13 . The lash adjuster of  claim 2  wherein said adjusting screw includes a head ( 91 ) protruding from the nut member ( 14 ) and having an outer diameter larger than the inner diameter of the nut member ( 14 ), whereby said adjusting screw serves as said initial setting means ( 15 ). 
     
     
         14 . The lash adjuster of  claim 13  wherein said adjusting screw ( 15 ) has a tapered surface ( 92 ) formed on its portion protruding from the nut member ( 14 ), said tapered surface ( 92 ) being configured to be brought into contact with a tapered surface ( 93 ) formed on the nut member ( 14 ) when the adjusting screw ( 15 ) is threaded into the nut member ( 14 ), thereby producing frictional resistance to rotation. 
     
     
         15 . The lash adjuster of  claim 14  wherein said adjusting screw ( 15 ) and the nut member ( 14 ) are degreased. 
     
     
         16 . The lash adjuster of  claim 2  wherein said initial setting means ( 122 ) is an annular member engaged in a circumferential groove ( 121 ) formed in an outer periphery of a portion of the adjusting screw ( 15 ) protruding from the nut member ( 14 ) and having an outer diameter larger than the inner diameter of the nut member ( 14 ). 
     
     
         17 . The lash adjuster of  claim 16  wherein said annular member is an O-ring ( 122 ) made of rubber. 
     
     
         18 . The lash adjuster of  claim 16  wherein said annular member is a ring made of an elastic resin. 
     
     
         19 . The lash adjuster of  claim 16  wherein said annular member is a conical coil spring ( 123 ) having a small-diameter end engaged in the circumferential groove ( 121 ) with a radial interference fit. 
     
     
         20 . The lash adjuster of  claim 16  wherein said annular member is a cylindrical coil spring ( 126 ) comprising two coil windings and engaged in the circumferential groove ( 121 ) with a radial interference fit. 
     
     
         21 . The lash adjuster of  claim 16  wherein said annular member is a cocoon-shaped clip ( 132 ) comprising two C-shaped annular portions ( 133  and  134 ) having different centers and coupled together, one of said two C-shaped annular portions ( 133 ) being corrugated in the axial direction, and wherein said cocoon-shaped clip ( 132 ) is slidable between a position where said one C-shaped annular portion ( 133 ) is engaged in the circumferential groove ( 121 ) and a position where the other C-shaped annular portion ( 134 ) is engaged in the circumferential groove ( 121 ). 
     
     
         22 . The lash adjuster of  claim 21  wherein said C-shaped annular portions ( 133  and  134 ) are circular or polygonal. 
     
     
         23 . The lash adjuster of  claim 16  wherein said annular member is a set clip ( 128 ) comprising a C-shaped annular portion ( 129 ) engaged in the circumferential groove ( 121 ) with a radial interference fit, and a pair of resetting tabs ( 130 ) extending from two ends of the C-shaped annular portion ( 129 ), respectively. 
     
     
         24 . The lash adjuster of  claim 23  wherein the C-shaped annular portion ( 129 ) is corrugated in the axial direction. 
     
     
         25 . The lash adjuster of  claim 19  wherein the conical coil spring ( 123 ) has a large-diameter end, and includes a resetting tab ( 124 ) radially outwardly extending from the large-diameter end. 
     
     
         26 . The lash adjuster of  claim 20  wherein the cylindrical coil spring ( 126 ) includes a resetting tab ( 127 ) radially outwardly extending from one end thereof. 
     
     
         27 . The lash adjuster of  claim 24  wherein the resetting tab ( 130 ) extending from one end of the C-shaped annular portion ( 129 ) crosses the resetting tab ( 130 ) extending from the other end of the C-shaped annular portion ( 129 ). 
     
     
         28 - 30 . (canceled)