Boom assembly for a trencher machine

A boom assembly for a trencher having a digging chain and tooth assembly entrained at one end about a chain drive sprocket, said boom assembly comprising:

• an elongated boom having a first end connected to said trencher for vertical movement about a generally horizontal axis, said boom having a bifurcated second end defining first and second apertured side walls;
• a boom end idler assembly rotatably arranged toward the second end of said boom between said side walls and about which the chain and tooth assembly is entrained, said boom end idler assembly including a boom end idler with an anti-friction bearing centrally accommodated therewithin, said bearing having inner and outer races with anti-friction rolling members entrapped therebetween;
• seals disposed between opposite sides of said bearing and said side walls of said boom for inhibiting debris from contaminating said bearing means;
• and
• a clamp mechanism having an outer periphery contained within an outer periphery of said side walls and passing through the apertures in said side members and at least partially within the inner race of said bearing means for defining the rotational axis of said boom end idler assembly said clamp mechanism clamping the side walls of the boom to each other to minimize clearances between the boom end idler assembly and the inner surfaces of the side walls of the boom, and wherein said clamp mechanism includes adjustable members readily accessible from opposite sides of said boom for variably adjusting the clamping force applied against the side members of the boom.

A trencher boom assembly adapted to have an endless digging chain with digging elements rotatable thereabout, said boom assembly comprising:

• a boom with rear pivot means for allowing said boom to vertically move about a generally horizontal axis between transport and digging positions, said boom including an elongated rigid housing having a rear end adapted for releasible securement to said pivot means and a forward end, said housing having a pair of side walls laterally spaced apart by a predetermined distance, each of said side walls defining an aperture toward a forward end of the side wall and with the apertures in said side walls being axially aligned relative to each other, said side walls being joined by top and bottom walls disposed between extended reaches of the endless chain;
• a boom end idler disposed between the side walls of said boom housing toward the forward end thereof, said boom end idler supporting the digging chain for movement about a fixed forward axis;
• bearing means accommodated within a central bore defined by said boom end idler, said bearing means including inner and outer races with a plurality of rolling members captively maintained therebetween;
• a pair of axially aligned members inwardly extending through the side walls of said boom housing in opposite directions toward each other and at least partially within the inner race of said bearing means for defining a fixed axis for said boom end idler, said axially aligned members exerting a clamping force which maintains minimum clearances between said side walls on the boom and the boom end idler;
• and
• seal means disposed between opposite sides of said bearing means and said side walls of said boom housing for closing the clearances between the side walls of the boom and the boom end idler thereby inhibiting dirt and other debris from contaminating said bearing means.

A trencher boom assembly adapted to have a digging chain and tooth assembly rotatable thereabout, said boom assembly comprising:

• a boom including a walled housing having rear and forward ends, said housing including a pair of side walls laterally spaced apart by a predetermined distance and joined by top and bottom walls extending for a portion of the length of the side walls and terminating short of the forward end of said housing;
• a boom end idler assembly rotatably mounted toward the forward end of the boom between said side walls and about which the chain and tooth assembly is entrained, said boom end idler assembly including a boom end idler supported for rotation by a bearing, said boom end idler having a thickness which is less than the predetermined distance between said side walls of the boom housing such that clearances are provided between the boom end idler and the boom housing to facilitate free rotation of the boom end idler assembly relative to the boom housing, and with said bearing means including end faces which project beyond opposite sides of the boom end idler and against the side walls of the housing;
• a pair of substantially identical clamp members passing inwardly through and from opposite sides of said side walls and for drawing the side walls of the boom housing toward each other and into abutting relation with the end faces of the bearing to minimize the clearances between the boom end idler assembly and the side walls of the boom housing thereby inhibiting contamination of the bearing from foreign matter passing through the clearances on opposite sides of the boom end idler assembly.

A trencher boom assembly adapted to have a digging chain and tooth assembly rotatable thereabout, said boom assembly comprising:

• a boom including a walled housing having rear and forward ends, said housing including a pair of laterally spaced side walls joined by top and bottom walls, said top and bottom walls terminating short of the forward end of the boom housing;
• a boom end idler assembly rotatably mounted toward the forward end of the boom between said side walls and about which the chain and tooth assembly is entrained, said boom end idler assembly including a boom end idler having an anti-friction bearing assembly journalled by boom end idler support means carried by said boom, said anti-friction bearing assembly including inner and outer races with a series of roller means captively maintained therebetween;
• and
• seal assemblies disposed between opposite sides of said bearing means and said side walls of the boom housing for inhibiting foreign debris from contaminating said bearing means, each seal assembly including a pair of non-metallic seal rings arranged in movable and layered relation relative to each other to facilitate rotation of the boom end idler relative to the boom housing, each of said rings having an inside diameter fitting about said boom end idler support means and an outside diameter which is greater than the outside diameter of the outer race of said bearing assembly.