Hammer for impact printing device

Claim 2

A printing hammer for striking a web backed by a rigid backing member comprising: a hammer body; a tip having areas overlapping and abutting said hammer body; and a buffer of resilient material disposed between said body and tip in said overlapping and abutting areas for transmitting impact force from said body to said tip, said resilient material having a modulus of elasticity lower than the modulus of the portions of said hammer body and tip immediately behind and in front of it.

Claim 3

The printing hammer described in claim 1 wherein: said tip has a portion forward of said body and a pair of legs extending rearwardly on either side of said body; and said buffer is disposed between said body and said tip portion which is forward of said body, and between said body and each of said legs. 3. A printing hammer comprising: a substantially flat hammer body portion of rigid construction; a tip of rigid material having an area abutting said hammer and at least one portion overlapping said hammer; and a layer of elastomeric material substantially more elastic than said tip and body portions, disposed between said tip and body portion in the abutting area and in the overlapping portion.

Claim 4

The printing hammer described in claim 3 wherein: said tip is of substantially U-shape with legs extending on either side of said flat body portion; and said layer of elastomeric material is joined to said body sides and legs of said tip. 5. In a printer including a rotating character member for printing on a web when the web is struck thereagainst by a hammer, the improvement comprising: a hammer body; means for moving said body toward and away from said character member; a tip of rigid material positioned on said hammer body for striking said web against said character member, said tip having areas overlapping and abutting said hammer body; and buffer means of elastomeric material having a smaller modulus of elasticity than said tip, joining said tip and body in the abutting and overlapping areas to permit limited moveMent of said tip with a tangential component of said rotating character member when they are in contact, without corresponding movement of said hammer body, whereby to prevent damage by upward or downward movement of said body when no web is present. 6. The improvement described in claim 5 wherein: said tip includes a front portion positioned forward of said hammer body, and legs extending from said front portion and positioned on either side of said body; and said buffer means is disposed between said body and said front portion and legs of said tip. 7. In a printer including a rotating character member for printing on a web when the web is struck thereagainst by a hammer, the improvement comprising: a hammer body; means for moving said body toward and away from said character member; a tip of rigid material positioned on said hammer body for striking said web against said character member, said tip having a front portion positioned forward of said hammer body and legs extending from said front portion and positioned on either side of said body; and buffer means of elastic material disposed between said body and said front portion and legs of said tip, for joining said tip and body to permit limited movement of said tip with a tangential component of said rotating character member when they are in contact, without corresponding movement of said hammer body; the depth of said legs and of the portion of said buffer means thereagainst being at least twice as great as the thickness of the body portion between said legs, whereby to secure said tip on said body against large upward or downward impulses when said tip contacts said character member.

Claim 5

In a printer as recited in claim 7 wherein said web is a web of paper; and wherein said elastic material of said buffer means has a modulus of elasticity when stressed by the impact of said hammer tip on said web, which is at least twice as great as the modulus of elasticity of said web when it is stressed as said tip strikes it.