Fatigue-resistant attachment for highly stressed members such as print hammers

Claim 2

A steel flexure-spring supported ballistic print-hammer apparatus comprising: a polymeric material hammer member having a holelike receptacle having substantially cylindrically shaped walls, the receptacle cylindrical axis being transverse to the length of said polymeric material hammer member; at least one steel flexure-spring fixedly connected at one end thereof to said polymeric material hammer member for supporting and guiding said polymeric material hammer member; a first layer of elastomeric structural adhesive material adherently disposed on said cylindrically shaped walls of said holelike receptacle of said polymeric material hammer member; said one end of said steel flexure-spring having a substantially closed circular shape including external and internal curving surfaces, said external curving surface being adherently mated with said first layer of elastomeric structural adhesive material within said holelike receptacle; a second layer of elastomeric structural adhesive material adherently disposed on said steel flexure-spring internal curving surface; and a polymeric material pin member of substantially circular cross section, said polymeric material pin member being located within said substantially closed circular shape of said end portion of said steel flexure-spring and being adherently mated with said second layer of elastomeric structural adhesive material; whereby said polymeric material pin member, said secOnd layer of structural adhesive material, said one end of said steel flexure-spring, said first layer of structural adhesive material, and said cylindrical walls of said holelike receptacle are arranged in a nested coaxial relationship wherein said external and said internal curving surfaces of said one end of said steel flexure-spring having said substantially closed circular shape provides both mechanical anchoring for said steel flexure-spring and a large bonding surface therefor.

Claim 3

A steel flexure-spring supported ballistic print-hammer apparatus as in claim 1 wherein said first and second elastomeric structural adhesive layers are made of epoxy adhesive material containing an acrylonitrile butadiene modifier.

Claim 4

A steel flexure-spring supported ballistic print-hammer apparatus as in claim 1 wherein the apparatus also includes a first metal plate member located at the end of said steel flexure-spring opposite said polymeric material hammer member, said first metal plate member being of width greater than the width of said steel flexure-spring; a first layer of elastomeric structural adhesive material adherently disposed on said first metal plate member and one lateral surface of said end of said steel flexure-spring opposite said polymeric material hammer member; a second metal plate member located at said end of said steel flexure-spring opposite said polymeric material hammer member, said second metal plate member being similar in size to said first metal plate member; and a second layer of elastomeric structural adhesive material adherently disposed on said second metal plate member and the remaining lateral surface of said end of said steel flexure-spring opposite said polymeric material hammer member.

Claim 5

A steel flexure-spring supported ballistic print-hammer apparatus as in claim 3 wherein said first and second layers of elastomeric structural adhesive material adherently disposed on said first and second metal plate members are composed of epoxy adhesive material containing acrylonitrile butadiene as a modifier.

Claim 6

A steel flexure-spring supported ballistic print-hammer apparatus as in claim 1 wherein said polymeric material hammer member including said cylindrically shaped walls upon which said first layer of elastomeric structural adhesive material is disposed are composed of nylon material containing short randomly oriented particles of fiberglass.

Claim 7

Stress limiting attachment apparatus for securely joining a metal flexure support element to an internal portion of a polymeric material printing member in a long-life coupling tolerant or repeated bending in said flexure support element and impact acceleration of said polymeric material printing member, said attachment apparatus comprising the combination of: a polymeric material body portion for said printing member, said body portion including cavity means located transverse of, and near an end of, said body portion for attaching said metal flexure support element to said body portion, said cavity means including a curving internal bonding surface portion and means for admitting said metal flexure support element thereto; a shaped end portion of said metal flexure support element, said shaped end portion having a curving configuration with an internal surface and an external surface, the external surface being closely conformed to the shape of said body portion cavity means curving internal bonding surface portion; an organic material cavity filling means member located within said curving configuration of said shaped end portion of said metal flexure support element and closely conformed in configuration with said shaped end portion interior surface for filling the unoccupied portion of said cavity means and for supporting said shaped end portion of said metal flexure support element in conformity with said cavity means curving internal bonding surface portion; elastomeric structural adhesive bonding means located between said shaped end poRtion external surface of said metal flexure support element and said cavity means internal bonding surface portion of said polymeric material body portion and between said shaped end portion internal surface of said metal flexure support element and said organic material cavity filling means for bonding said shaped end portion of said metal flexure support element to said polymeric material body portion cavity means and to said organic material cavity filling means; whereby said metal flexure support element is retained within said body portion by a combination of mechanical anchoring and structural adhesive bonding means, said structural adhesive bonding means also providing a stress limiting interface between the relatively hard and rigid metal of said flexure support element and the relatively soft and resilient polymeric material of said body portion during dimensional alteration thereof by the strain of high energy impact acceleration.

Claim 8

Stress limiting attachment apparatus for securely joining a metal flexure support element to an internal portion of a polymeric material printing member in a long-life coupling tolerant or repeated bending in said flexure support element and impact acceleration of said polymeric material printing member, said attachment apparatus comprising the combination of: a polymeric material body portion for said printing member, said body portion including cavity means located transverse of, and near an end of, said body portion for attaching said metal flexure support element to said body portion, said cavity means including a curving internal bonding surface portion and means for admitting said metal flexure support element thereto; a shaped end portion of said metal flexure support element, said shaped end portion having a curving configuration with an internal surface and an external surface, the external surface being closely conformed to the shape of said body portion cavity means curving internal bonding surface portion; an organic material cavity filling means member located within said curving configuration of said shaped end portion of said metal flexure support element and closely conformed in configuration with said shaped end portion interior surface for filling the unoccupied portion of said cavity means and for supporting said shaped end portion of said metal flexure support element in conformity with said cavity means curving internal bonding surface portion; elastomeric structural adhesive bonding means located between said shaped end poRtion external surface of said metal flexure support element and said cavity means internal bonding surface portion of said polymeric material body portion and between said shaped end portion internal surface of said metal flexure support element and said organic material cavity filling means for bonding said shaped end portion of said metal flexure support element to said polymeric material body portion cavity means and to said organic material cavity filling means; whereby said metal flexure support element is retained within said body portion by a combination of mechanical anchoring and structural adhesive bonding means, said structural adhesive bonding means also providing a stress limiting interface between the relatively hard and rigid metal of said flexure support element and the relatively soft and resilient polymeric material of said body portion during dimensional alteration thereof by the strain of high energy impact acceleration.

Claim 9

Stress limiting attachment apparatus as in claim 6 wherein said elastomeric structural adhesive bonding means includes an epoxy structural adhesive modified with acrylonitrile butadiene.

Claim 10

Stress limiting attachment apparatus as in claim 6 wherein said organic material cavity filling means member includes a pin member composed of epoxy structural adhesive material.

Claim 11

Stress limiting attachment apparatus as in claim 6 wherein said organic material cavity filling means member includes a pin member composed of nylon.

Claim 12

Stress limiting attachment apparatus as in claim 6 wherein said elastomeric structural adhesive bonding means includes adhesive bonding material extending along said metal flexure support element away from said shaped end portion and to the exterior of said polymeric material body portion whereby the stiffness of said metal flexure support element is graduated by said adhesive bonding material in the metal flexure support element region joining said shaped end portion.

Claim 13

Apparatus for supporting a nonmetallic printing member from a stationary structural portion of a printing mechanism; said apparatus comprising: at last one metal flexure support element connected at a first end portion thereof with said nonmetallic printing member and at a second end portion thereof with said stationary structural portion of said printing mechanism; attachment means for attaching said first end portion of said metal flexure support element to said nonmetallic printing member; a first plate member rigid with respect to said metal flexure support element and located adjacent said second end portion thereof, and located between said second end portion and said stationary structural portion of said printing mechanism, said plate member being of at least twice the lateral width of said flexure support element; a second plate member substantially similar in size to said first plate member and rigid with respect to said metal flexure support element and located facing said first plate member with said metal flexure support element second end portion being located between said first and second plate members; elastomeric structural adhesive bonding means located between said metal flexure support element second end portion and said first plate member and between said flexure support element second end portion and said second plate member for bonding said flexure support element second end portion to said first and second plate members and for uniting said flexure support element and said plate members into a unitary assembly; means for attaching said unitary assembly to said stationary structural portion of said printing mechanism; whereby said plate members and said elastomeric structural adhesive bonding means retain said second end portion of said metal flexure support element in a sandwichlike structure providing large bonding surfaces and graduated rigidity for said flexure support element at said second end portion, and said plate members provide a manifold structure capable of unitIng a plurality of flexure support elements and associated printing members into a unitary assembly for convenient insertion and removal from said printing mechanism.

Claim 14

Apparatus for supporting a nonmetallic printing member from a stationary structural portion of a printing mechanism; said apparatus comprising: at last one metal flexure support element connected at a first end portion thereof with said nonmetallic printing member and at a second end portion thereof with said stationary structural portion of said printing mechanism; attachment means for attaching said first end portion of said metal flexure support element to said nonmetallic printing member; a first plate member rigid with respect to said metal flexure support element and located adjacent said second end portion thereof, and located between said second end portion and said stationary structural portion of said printing mechanism, said plate member being of at least twice the lateral width of said flexure support element; a second plate member substantially similar in size to said first plate member and rigid with respect to said metal flexure support element and located facing said first plate member with said metal flexure support element second end portion being located between said first and second plate members; elastomeric structural adhesive bonding means located between said metal flexure support element second end portion and said first plate member and between said flexure support element second end portion and said second plate member for bonding said flexure support element second end portion to said first and second plate members and for uniting said flexure support element and said plate members into a unitary assembly; means for attaching said unitary assembly to said stationary structural portion of said printing mechanism; whereby said plate members and said elastomeric structural adhesive bonding means retain said second end portion of said metal flexure support element in a sandwichlike structure providing large bonding surfaces and graduated rigidity for said flexure support element at said second end portion, and said plate members provide a manifold structure capable of unitIng a plurality of flexure support elements and associated printing members into a unitary assembly for convenient insertion and removal from said printing mechanism.