Plural-part earth bit, and an improved bit head therefor

Claim 2

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially-extended cavity formed therein; said cavity defining a first wall, substantially smoothly threaded and of a given pitch diameter, which circumscribes said axis, wherein the improvement comprises: means lining said first wall defining a second, threaded wall which circumscribes said axis, said defined second wall having a thread with a pitch diameter which is less than said given diameter; wherein said lining means comprises means which, along a given radial plane drawn outwardly from said axis, defines a plurality of lamina; each lamina of said plurality, along said given plane, terminates radially inwardly in an individual, rigid, surface of a given axial dimension; the median of any one of said individual surfaces, of a plurality of said surfaces, measured along said given radial plane, is disposed at a given radial distance from said axis; and the median of another such surface immediately adjacent to said any one individual surface, measured along said plane, is disposed at a radial distance from said axis other than said given distance.

Claim 3

An improved bit head, for a plural-part earth bit, according to claim 1, wherein: said individual surfaces are all parallel with said axis.

Claim 4

An improved bit head, for a plural-part earth bit, according to claim 1, wherein: said lining means comprises a plurality of apertured discs.

Claim 5

An improved bit head, for a plural-part earth bit, according to claim 3, wherein: said discs all have a common outside diameter and a common inside diameter.

Claim 6

An improved bit head, for a plural-part earth bit, according to claim 3, wherein: said first wall has a thread lead of a given dimension X; and each of said discs has a thickness of approximately X/8.

Claim 7

An improved bit head, for a plural-part earth bit, according to claim 1, wherein: said cavity and lining means have means cooperative for retaining said lining means within said cavity.

Claim 8

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a pitch diameter which is less than said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; and each of said elements of said plurality is freely rotatable relative to any other thereof.

Claim 9

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a pitch diameter which is less than said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; and each of said elements of said plurality is freely rotatable relative to any other thereof.

Claim 10

An improved bit head, for a plural-part earth bit, according to claim 7, wherein a plurality of said elements are substantially identical.

Claim 11

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a pitch diameter which is less than said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; each of said elements of said plurality is freely rotatable relative to any other thereof; each of said elements has an aperture formed therethrough centrally thereof; said apertures of a given plurality of said elements are of a common dimension; and a plurality of said apertures are eccentrically disposed relative to said axis.

Claim 12

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a pitch diameter which is less than said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; each of said elements of said plurality is freely rotatable relative to any other thereof; each of said elements has an aperture formed therethrough centrally thereof; said apertures of a given plurality of said elements are of a common dimension; and a plurality of said apertures are eccentrically disposed relative to said axis.

Claim 13

An an improved bit head for a plural-part earth bit, according to claim 1, wherein: said first wall and lining means have means cooperative for retaining said elements within said bit head.

Claim 14

An improved bit head, for a plural-part earth bit, according to claim 10, wherein; said cooperative retaining means comprises a retainer; said bit head has a cavity formed therein; and said cavity has means for securing said retainer therewithin.

Claim 15

An improved bit, head, for a plural-part earth bit, according to claim 11, wherein: said securing means comprises a relief formed in said cavity.

Claim 16

An improved bit head, for a plural-part earth bit, according to claim 7, wherein: said first wall has a bearing surface lying normal to said axis; and said plurality of elements is walled-in, in said bit head, by said bearing surface.

Claim 17

An improved bit head, for a plural-part earth bit, according to claim 11, wherein: said cavity has means defining a first stabilizing surface of a given diametrical dimension, D, and means defining a second stabilizing surface of a diametrical dimension less than said given diametrical dimension, D; said second stabilizing surface has a prescribed axial length, L; and said prescribed axial length, L, is of a dimension which exceeds one-twentieth of said given diametrical dimension, D.

Claim 18

An improved bit head, for a plural-part earth bit, according to claim 11, wherein: said cavity (a) has an open end, (b) defines a bearing surface, lying normal to said axis, at a given distance, C, from said open end, (c) defines a first stabilizing surface of a given diameter, D, and (d) defines a second stabilizing surface, spaced apart from said first stabilizing surface, having a prescribed axial length, L; and said given distance, C, exceeds 0.45 times said given diameter, D, and said length, L exceeds 0.05 times said given diameter, D.

Claim 19

An improved bit head, for a plural-part with bit, according to claim 9, wherein: said elements of said given plurality thereof have a common outside diameter, and a common annular width defined by and between said outside diameter and said apertures therein; said first wall has a thread with a given depth; and

Claim 20

said annular width of said elements is greater than said given depth.

Claim 21

said annular width of said elements is greater than said given depth.

Claim 22

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially-extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; and each of said elements of said plurality is freely rotatable relative to any other thereof.

Claim 23

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially-extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; and each of said elements of said plurality is freely rotatable relative to any other thereof.

Claim 24

An improved bit head, for a plural-part earth bit, according to claim 17, wherein a plurality of said elements are substantially identical.

Claim 25

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially-extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; each of said elements of said plurality is freely rotatable relative to any other thereof; each of said elements has an aperture formed therethrough centrally thereof; said apertures of a given plurality of said elements are of a common dimension; and a plurality of said apertures are eccentrically disposed relative to said axis.

Claim 26

An improved bit head, for a plural-part earth bit, said head having a central axis, and an axially-extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining said first wall defining a second, threaded wall, circumscribing said axis, having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of individual, rigid, circular elements; each of said elements of said plurality is freely rotatable relative to any other thereof; each of said elements has an aperture formed therethrough centrally thereof; said apertures of a given plurality of said elements are of a common dimension; and a plurality of said apertures are eccentrically disposed relative to said axis.

Claim 27

An improved, plural-part, earth bit, comprising a bit shank having a threaded end, and a bit head, said head having a central axis, and an axially-extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread with a given pitch diameter, wherein the improvement comprises: means lining and engaging said first wall defining a second, threaded wall, which circumscribes said axis, and which threadedly engages said threaded end of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter, wherein said lining means comprises means which, along a given radial plane drawn outwardly from said axis, defines a plurality of lamina; each lamina of said plurality, along said given plane, terminates radially inwardly in an individual, rigid surface of a given axial dimension; the median of any one of said individual surfaces, of a plurality of said surfaces, measured along said given radial plane, is disposed at a given radial distance from said axis; and the median of another such surface immediately adjacent to said any one individual surface, measured along said plane, is disposed at a radial distance from said axis other than said given distance.

Claim 28

An improved, plural-part, earth bit, comprising a bit shank having a threaded end, and a bit head, said head having a central axis, and an axially-extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread with a given pitch diameter, wherein the improvement comprises: means lining and engaging said first wall defining a second, threaded wall, which circumscribes said axis, and which threadedly engages said threaded end of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter, wherein said lining means comprises means which, along a given radial plane drawn outwardly from said axis, defines a plurality of lamina; each lamina of said plurality, along said given plane, terminates radially inwardly in an individual, rigid surface of a given axial dimension; the median of any one of said individual surfaces, of a plurality of said surfaces, measured along said given radial plane, is disposed at a given radial distance from said axis; and the median of another such surface immediately adjacent to said any one individual surface, measured along said plane, is disposed at a radial distance from said axis other than said given distance.

Claim 29

An improved, plural-part, earth bit, according to claim 20, wherein: said individual surfaces are all parallel with said axis.

Claim 30

An improved, plural-part, earth bit, according to claim 20, wherein: said lining means is formed of a plurality of apertured discs.

Claim 31

An improved, plural-part, earth bit, according to claim 22, wherein: said discs all have a common outside diameter and a common inside diameter.

Claim 32

An improved, plural-part, earth bit, according to claim 22, wherein: said thread of said first wall has a thread lead of a given dimension X; and each of said discs has a thickness of approximately X/8.

Claim 33

An improved, plural-part, earth bit, according to claim 20, wherein: said bit head and lining means have means cooperative for retaining said lining means in engagement with said first wall.

Claim 34

An improved, plural-part, earth bit, comprising a bit shank which is threaded along a portion thereof, and a bit head, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining and engaging said first wall defining a second threaded wall which circumscribes said axis, and which threadedly engages said threaded portion of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of lamina; each lamina of said plurality presents an individual, rigid, circular surface circumscribing said axis; and each of said laminae is rotatable relative to any other thereof.

Claim 35

An improved, plural-part, earth bit, comprising a bit shank which is threaded along a portion thereof, and a bit head, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining and engaging said first wall defining a second threaded wall which circumscribes said axis, and which threadedly engages said threaded portion of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of lamina; each lamina of said plurality presents an individual, rigid, circular surface circumscribing said axis; and each of said laminae is rotatable relative to any other thereof.

Claim 36

An improved, plural-part, earth bit, according to claim 26, wherein: a given plurality of said laminae are substantially identical.

Claim 37

An improved, plural-part, earth bit, comprising a bit shank which is threaded along a portion thereof, and a bit head, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining and engaging said first wall defining a second threaded wall which circumscribes said axis, and which threadedly engages said threaded portion of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of lamina; each lamina of said plurality presents an individual, rigid, circular surface circumscribing said axis; each of said laminae is rotatable relative to any other thereof; each lamina of said plurality thereof has an aperture formed therethrough centrally thereof; said apertures of a given plurality of said laminae are of a common dimension; and a plurality of said common-dimension apertures are eccentrically disposed relative to said axis.

Claim 38

An improved, plural-part, earth bit, comprising a bit shank which is threaded along a portion thereof, and a bit head, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining and engaging said first wall defining a second threaded wall which circumscribes said axis, and which threadedly engages said threaded portion of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of lamina; each lamina of said plurality presents an individual, rigid, circular surface circumscribing said axis; each of said laminae is rotatable relative to any other thereof; each lamina of said plurality thereof has an aperture formed therethrough centrally thereof; said apertures of a given plurality of said laminae are of a common dimension; and a plurality of said common-dimension apertures are eccentrically disposed relative to said axis.

Claim 39

An improved, plural-part, earth bit, according to claim 26, wherein: said bit head and lining means have means cooperative for retaining said laminae in lined engagement with said first wall.

Claim 40

An improved, plural-part, earth bit, according to claim 26, wherein: said first wall has a bearing surface lying normal to said axis; and said laminae are held against axial removal from said bit head by said bearing surface.

Claim 41

An improved, plural-part, earth bit, according to claim 26, wherein: said first wall has means defining a first shank stabilizing surface of a given diametrical dimension and means defining a second shank stabilizing surface of a diametrical dimension less than said given dimension; one of said first and second stabilizing surfaces has a prescribed axial length; and said prescribed axial length is of a dimension which is more than one-twentieth of said given diametrical dimension.

Claim 42

An improved, plural-part, earth bit, comprising a bit shank which is threaded along a portion thereof, and a bit head, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining and engaging said first wall defining a second threaded wall which circumscribes said axis, and which threadedly engages said threaded portion of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of lamina; each lamina of said plurality presents an individual, rigid, circular surface circumscribing said axis; each of said laminae is rotatable relative to any other thereof; and said first wall (a) has a terminal end, (b) defines a bearing surface, lying normal to said axis, at a given distance, C, from said terminal end, (c) defines a first stabilizing surface of a given diameter, D, and (d) defines a second stabilizing surface, spaced apart from said first stabilizing surface, having a prescribed axial length, L; and said given distance, C, exceeds 0.45 times said given diameter, D, and said length, L, exceeds 0.05 times said given diameter, D.

Claim 43

An improved, plural-part, earth bit, comprising a bit shank which is threaded along a portion thereof, and a bit head, said head having a central axis, and an axially extended, circumferential, first wall, which circumscribes said axis, said first wall having a thread of a given pitch diameter, wherein in the improvement comprises: means lining and engaging said first wall defining a second threaded wall which circumscribes said axis, and which threadedly engages said threaded portion of said shank; said defined second wall having a thread with a pitch diameter which differs from said given diameter; wherein said lining means comprises a plurality of lamina; each lamina of said plurality presents an individual, rigid, circular surface circumscribing said axis; each of said laminae is rotatable relative to any other thereof; and said first wall (a) has a terminal end, (b) defines a bearing surface, lying normal to said axis, at a given distance, C, from said terminal end, (c) defines a first stabilizing surface of a given diameter, D, and (d) defines a second stabilizing surface, spaced apart from said first stabilizing surface, having a prescribed axial length, L; and said given distance, C, exceeds 0.45 times said given diameter, D, and said length, L, exceeds 0.05 times said given diameter, D.

Claim 44

An improved, plural-part, earth bit, according to claim 28, wherein: said laminae of said given plurality thereof have a common outside diameter, and a common annular width defined by and between said outside diameter and said apertures therein; said first wall has a thread with a given depth; and said annular width of said elements is greater than said given depth.