Fastening part structure for FRP member, metal collar, and method of attaching metal collar

A fastening part structure for an FRP member comprising

• a metal collar attached in a first through-hole formed in the FRP member, the metal collar forming a second through-hole extending through the FRP member, wherein
• the metal collar includes:
• a collar member, an outer circumferential surface of which is in contact with a hole inner circumferential surface of the first through-hole, a part of the collar member in a circumferential direction of the outer circumferential surface being provided with a slit communicating from one end face to another end face of the collar member;
• and
• a wedge member driven into the slit, the wedge member applying a pressing force in a direction in which inner surfaces of the slit separate in the circumferential direction, and
• the wedge member is held in the collar member by reaction of the pressing force, deforms the collar member for diameter expansion with the pressing force, and presses the outer circumferential surface of the collar member against the hole inner circumferential surface.

A method of attaching a metal collar in a first through-hole formed in an FRP member, the metal collar forming a second through-hole extending through the FRP member, the method comprising:

• preparing a metal collar including:
• an annular or tubular outer collar member which includes an outer circumferential surface that comes into contact with a hole inner circumferential surface of the first through-hole when the outer collar member is attached in the first through-hole, and which is provided with a slit in a part of the outer collar member in a circumferential direction of the outer circumferential surface, the slit communicating from one end face to another end face of the outer collar member, and thereby is configured to be deformable in a radial direction of the first through-hole;
• and
• an inner collar member including, at least in a part of an outer circumferential surface, a pressing surface capable of applying a pressing force outward in the radial direction to at least a part of an inner circumferential surface of the outer collar member when the inner collar member is fitted into the inner circumferential surface, the inner collar member including a flange section whose outer circumferential edge portion is located outside in the radial direction than the hole inner circumferential surface;
• fitting the outer collar member into the hole inner circumferential surface of the first through-hole;
• fitting the inner collar member into the inner circumferential surface of the outer collar member;
• bringing the pressing surface into contact with at least a part of the inner circumferential surface of the outer collar member to apply a pressing force outward in the radial direction from the pressing surface to at least a part of the inner circumferential surface by rotating the inner collar member around an axis of the first through-hole relative to the outer collar member,
• wherein the inner collar member is held in the outer collar member with reaction of the pressing force and deforms the outer collar member for diameter expansion with the pressing force to press the outer circumferential surface of the outer collar member against the hole inner circumferential surface.

A method of attaching a metal collar in a first through-hole formed in an FRP member, the metal collar forming a second through-hole extending through the FRP member, the method comprising:

• preparing a metal collar including:
• a collar member which includes an outer circumferential surface that comes into contact with a hole inner circumferential surface of the first through-hole when the collar member is attached in the first through-hole, and which is provided with a slit in a part in a circumferential direction of the outer circumferential surface, the slit communicating from one end face to another end face of the collar member, and thereby is configured to be deformable in a radial direction of the first through-hole;
• and
• a wedge member including pressing surfaces capable of, when the wedge member is driven into the slit, applying a pressing force to inner surfaces of the slit in a direction in which the inner surfaces separate from each other in the circumferential direction;
• fitting the collar member into the hole inner circumferential surface of the first through-hole;
• driving the wedge member into the slit;
• bringing the pressing surfaces into contact with the inner surfaces of the slit to apply, to the inner surfaces of the slit from the pressing surfaces, the pressing force in the direction in which the inner surfaces separate from each other in the circumferential direction;
• and
• holding the wedge member in the collar member by reaction of the pressing force and deforming the collar member for diameter expansion with the pressing force to press the outer circumferential surface of the collar member against the hole inner circumferential surface.

A fastening part structure for an FRP member comprising a metal collar attached in a first through-hole formed in the FRP member, the metal collar forming a second through-hole extending through the FRP member, wherein the metal collar includes:

• a first member including an outer circumferential surface in contact with a hole inner circumferential surface of the first through-hole and an inner circumferential surface located on an inner side of the outer circumferential surface in a radial direction of the first through-hole, a part of the first member in a circumferential direction of the outer circumferential surface being provided with a slit communicating from one end face to another end face of the first member;
• and
• a second member that applies a pressing force outward in the radial direction to at least a part of the inner circumferential surface, wherein the pressing force outward in the radial direction to at least the part of the inner circumferential surface is applied by a rotation of the second member around an axis of the first through-hole relative to the first member, and the second member is held in the first member by reaction of the pressing force and deforms the first member for diameter expansion with the pressing force to press the outer circumferential surface of the first member against the hole inner circumferential surface,
• the second member includes a flange section whose outer circumferential edge portion is located outside in the radial direction than the hole inner circumferential surface.

A metal collar to be attached in a first through-hole formed in an FRP member, the metal collar forming a second through-hole extending through the FRP member, the metal collar comprising:

• a first collar member which includes an outer circumferential surface that comes into contact with a hole inner circumferential surface of the first through-hole when being attached in the first through-hole and an inner circumferential surface located on an inner side of the outer circumferential surface in a radial direction of the first through-hole, and which is provided with a slit in a part of the first collar member in a circumferential direction of the outer circumferential surface, the slit communicating from one end face to another end face of the first collar member, and thereby is configured to be deformable in the radial direction of the first through-hole;
• and
• a second collar member including a pressing surface that applies a pressing force outward in the radial direction to at least a part of the inner circumferential surface, where the pressing force is applied when the second collar member is fitted into the inner circumferential surface of the first collar member and rotated around an axis of the first through-hole relative to the first collar member, wherein
• the second collar member is configured to be held in the first collar member by reaction of the pressing force and deform the first collar member for diameter expansion with the pressing force to press the outer circumferential surface of the first collar member against the hole inner circumferential surface,
• the second collar member includes a flange section whose outer circumferential edge portion is located outside in the radial direction than the hole inner circumferential surface.

A fastening part structure for an FRP member comprising:

• a metal collar attached in a first through-hole formed in the FRP member, the metal collar forming a second through-hole extending through the FRP member, wherein
• the metal collar includes:
• an annular or tubular outer collar member, an outer circumferential surface of which is in contact with a hole inner circumferential surface of the first through-hole, a part of the outer collar member in a circumferential direction of the outer circumferential surface being provided with a slit communicating from one end face to another end face of the outer collar member;
• and
• an inner collar member fitted into an inner circumferential surface of the outer collar member, at least a part of an outer circumferential surface of the inner collar member being in contact with at least a part of the inner circumferential surface to apply a pressing force outward in a radial direction of the first through-hole to at least the part of the inner circumferential surface, wherein the pressing force is applied by a rotation of the inner collar member around an axis of the first through-hole relative to the outer collar member, and
• the inner collar member is held in the outer collar member by reaction of the pressing force, and applies the pressing force to deform the outer collar member for diameter expansion and to press the outer circumferential surface of the outer collar member against the hole inner circumferential surface,
• wherein a self-tapping screw having an outer diameter larger than a value obtained by subtracting a double of thickness in the radial direction of the outer collar member from an inner diameter of the hole inner circumferential surface is formed on the outer circumferential surface of the inner collar member, and
• a screw thread of the self-tapping screw bites into the inner circumferential surface of the outer collar member to apply the pressing force outward in the radial direction to the inner circumferential surface.

A method of attaching a metal collar in a first through-hole formed in an FRP member, the metal collar forming a second through-hole extending through the FRP member, the method comprising:

• preparing a metal collar including:
• an annular or tubular outer collar member which includes an outer circumferential surface that comes into contact with a hole inner circumferential surface of the first through-hole when the outer collar member is attached in the first through-hole, and which is provided with a slit in a part of the outer collar member in a circumferential direction of the outer circumferential surface, the slit communicating from one end face to another end face of the outer collar member, and thereby is configured to be deformable in a radial direction of the first through-hole;
• and
• an inner collar member including, at least in a part of an outer circumferential surface, a pressing surface capable of applying a pressing force outward in the radial direction to at least a part of an inner circumferential surface of the outer collar member when the inner collar member is fitted into the inner circumferential surface;
• fitting the outer collar member into the hole inner circumferential surface of the first through-hole;
• fitting the inner collar member into the inner circumferential surface of the outer collar member;
• bringing the pressing surface into contact with at least a part of the inner circumferential surface of the outer collar member to apply a pressing force outward in the radial direction from the pressing surface to at least a part of the inner circumferential surface by rotating the inner collar member around an axis of the first through-hole relative to the outer collar member,
• forming, on an outer circumferential surface of the inner collar member, a self-tapping screw having an outer diameter larger than a value obtained by subtracting a double of thickness in the radial direction of the outer collar member from an inner diameter of the hole inner circumferential surface;
• and
• after fitting the outer collar member into the hole inner circumferential surface, screwing the self-tapping screw into the inner circumferential surface of the outer collar member and causing a screw thread of the self-tapping screw to bite into the inner circumferential surface of the outer collar member,
• wherein the inner collar member is held in the outer collar member with reaction of the pressing force and deforms the outer collar member for diameter expansion with the pressing force to press the outer circumferential surface of the outer collar member against the hole inner circumferential surface.