Abstract The leaves of a book constructed and arranged for flexing during the act of thumbing are arranged as a sequential series of sections, each constituted of a group of leaves wherein the first page face carries indicia identifying that particular group. Each leaf immediately preceding the first leaf of the next following group is an indexing leaf having at its index side edge a marginal zone more flexible than the marginal zones at the index side edges of the immediately preceding and the next following group leaf. The index edges of all leaves have a thumb pressure point that lies in a plane common to all the points and normal to the turning axis of the leaves. The pressure points of the indexing leaves are constructed and arranged so that they are less influenced by thumb pressure than are the pressure points of the group leaf immediately preceding and the group leaf next following each indexing leaf.
Inventors
👤 A Friedman
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-02 17:01
CPC Classifications
B; B42; B42F; B42F21/00
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
112 words
In a book having its leaves constructed and arranged for progressive flexing in a thumbing operation and disposed as a sequential series of individual groups of consecutive leaves wherein the groups are separated by an indexing leaf immediately preceding the first leaf of each group and having therein a slit open to its outer side edge, each slit extending inwardly therein and making the area of that leaf adjacent the slit a pressure point more flexible under thumb pressure applied to that point than the remainder of the leaf, and all said indexing leaf slits being in a single plane common thereto and angled relative to the turning axis of the leaves.
Claim 2
Dependent Claim
112 words
In a book having its leaves constructed and arranged for progressive flexing in a thumbing operation and disposed as a sequential series of individual groups of consecutive leaves wherein the groups are separated by an indexing leaf immediately preceding the first leaf of each group and having therein a slit open to its outer side edge, each slit extending inwardly therein and making the area of that leaf adjacent the slit a pressure point more flexible under thumb pressure applied to that point than the remainder of the leaf, and all said indexing leaf slits being in a single plane common thereto and angled relative to the turning axis of the leaves.
Claim 3
Dependent Claim
34 words
In the book of claim 1, each indexing leaf slit overlying, when the book is closed, group identification indicia on the first page face of the group leaf which the indexing leaf immediately precedes.