Railroad car draft gear having a long travel

A friction/elastomeric draft gear comprising:

• a hollow housing open at a first end and closed toward a second end, said housing defining a major axis and having a series of longitudinally extended tapered inner surfaces opening toward and longitudinally extending from a front portion arranged adjacent the first end of said housing;
• a series of equally and annularly spaced friction shoes arranged for limited radial movement relative to the major axis of said housing, with each friction shoe including a first end portion with a first inner angled surface, a second end portion, and an outer surface between said first and second end portions, with the outer surface of each friction shoe being slidably engagable with one of the respective radially opposed longitudinally extended tapered inner surfaces on said housing, and wherein said outer surface for each friction shoe and the radially opposed longitudinally extended tapered inner surface on said housing each being disposed in a plane defining a first selected angle relative to the major axis of said housing;
• a wedge arranged for axial movement relative the open end of said housing, said wedge having a free end extending outwardly beyond the first end of said housing and against which an external force can be applied, said wedge defining a series of outer tapered surfaces which engage and slide along the first inner angled surface on each friction shoe, with the outer tapered surfaces on the wedge and the first inner angled surface on each friction shoe each being disposed in a plane defining a second selected angle relative to the major axis of said housing, and with the wedge defining a generally centrally disposed axial bore open at opposite ends;
• a spring seat arranged within and at a generally normal disposition relative to the major axis of said housing, said spring seat defining on one side thereof a face which engages a surface disposed adjacent the second end portion on each friction shoe, with the face on said spring seat and the surface disposed adjacent the second end portion of each friction shoe each being disposed in a plane defining a third selected angle relative to the major axis of said housing, and with said spring seat defining a generally centrally disposed throughbore;
• an elastomeric spring within said hollow housing between the closed end of said housing and a side of the spring seat opposed to said one side whereby said spring package stores energy applied to said wedge during compression of said draft gear;
• said elastomeric spring including a series of elastomeric pads arranged in stacked relation relative to each other, with each elastomeric pad in said stack defining a centralized bore extending therethrough;
• a guide extending from the closed end and extending toward the open end of said housing, said guide passing endwise through the centralized bore in the elastomeric pads comprising said elastomeric spring, through the centralized bore in said spring seat, and at least partially through the throughbore in said wedge for promoting axial contraction/expansion of said elastomeric spring in response to the axial forces applied to said draft gear, and
• wherein said elastomeric spring in combination with the configuration of said housing, said wedge, said friction shoes and said spring seat along with the angularity of said first selected angle, said second selected angle and said third selected angle permitting said draft gear to resist impact forces applied thereto while cushioning said impact forces over an extended range of operation exceeding an axial cumulative length in excess of 7 inches.

A fiction/elastomeric draft gear comprising:

• a hollow housing open at a first end and closed toward a second end, said housing defining a major axis and having a series a series of longitudinally extended tapered inner surfaces opening toward and longitudinally extending from a front portion arranged adjacent the first end of said housing, and wherein the first and second ends of said housing define generally parallel surfaces with a predetermined length therebetween;
• a series of annularly spaced friction shoes, each friction shoe including a first end portion with a first angled surface and a second end portion and an outer surface between said first and second end portions, with the outer surface of each friction shoe being slidably engagable with one of the respective radially opposed longitudinally extended tapered inner surfaces on said housing, and wherein said outer surface for each friction shoe and the radially opposed longitudinally extended tapered inner surface on said housing each being disposed in substantially matching relation relative to each other and in a plane defining a first selected angle relative to the major axis of said housing;
• a wedge arranged for axial movement relative the open end of said housing, said wedge having a free end extending outwardly beyond the first end of said housing a distance of about 118 mm when said draft gear is at a full operative length and against which an external force can be applied, said wedge defining an outer tapered portion which combines with said first inner angled surface on each friction shoe to urge said shoes radially outward relative to the major axis of said housing upon compression of said draft gear;
• a spring seat arranged within and at a generally normal disposition relative to the major axis of said housing, said spring seat defining on one side thereof a face which combines with said second end portion on each friction shoe and which defines a third selected angle relative to the major axis of said housing;
• an elastomeric spring within said hollow housing between the closed end of said housing and a side of the spring set opposed to said one side whereby said spring package store energy applied to said wedge during compression of said draft gear from said fill operative length, with said elastomeric spring being compressed under a preload;
• and
• wherein the angles provided between said housing, said friction shoes, said wedge, and said spring seat are such that said draft gear provides a working stroke of about 118 mm and an available travel to installed length ratio of about 0.21.