Dowel joint system for connecting elements of a solid material

A drilling assembly for drilling a blind hole in a material from a surface of the material, the blind hole having a second hole portion spaced from the surface which is of a diameter greater than that of a first hole portion thereof adjacent the surface, the drilling assembly comprising:

• a drilling assembly body having a first drilling element and a second drilling element each arranged for common rotation with the drilling assembly body;
• means mounting the second drilling element on the body for movement relative to the first drilling element in response to pressure applied longitudinally to the drilling assembly body;
• chuck means for grasping the drilling assembly body for rotating the drilling assembly body and for applying pressure longitudinally to the drilling assembly body;
• means locking the second drilling element against said movement relative to the first drilling element such that the pressure and rotation applied to the drilling assembly causes the first drilling element to effect cutting of a cylindrical hole defining said first hole portion by engagement of the material with the first drilling element;
• an actuating member mounted on the drilling assembly body at a position thereon arranged for engaging the first surface of the material after drilling the cylindrical hole to a predetermined depth;
• the rigid locking member in a locking position being held by the actuating member in engagement with a first surface fixed on the first drilling element and a second surface fixed on the second drilling element so as to hold the first and second drilling elements in common fixed position;
• the actuating member being moveable relative to the first and second surfaces;
• said actuating member being arranged such that drilling of the first portion to a predetermined depth causes said movement of the actuating member relative to the first and second surfaces to release the locking member from said engagement with one of said first and second surfaces to allow said second drilling element to be moved by said longitudinal pressure to a position to cut from said cylindrical hole said second hole portion.

A method of fastening a dowel to a part of a solid material comprising:

• providing a first part of the solid material having an outside surface thereof;
• drilling a blind hole in the outside surface of the first part, the blind hole having a first hole portion thereof adjacent the outside surface, which has an inside surface which is cylindrical, and a second hole portion spaced from the surface which has an inside surface which is substantially frusto-conical increasing in diameter from a first diameter equal to that of the first portion to a second diameter which is greater than the first diameter;
• providing a dowel which is shaped with a first portion and a second portion corresponding to the first and second hole portions respectively, the dowel being shaped and arranged such that, in an initial, relaxed condition of the dowel, the first and second portions of the dowel each have an outside surface which is substantially equal in outside shape to the inside surface of the first and second portions of the hole;
• the dowel having a bore therealong;
• the dowel being formed so as to define a plurality of angularly separated parts at the second portion allowing the second portion to be compressed radially inwardly;
• compressing the second portion radially inwardly so that the second portion is substantially cylindrical with a diameter substantially equal to the first diameter;
• with the second portion compressed, inserting an end of the dowel into the blind hole through the outside surface;
• allowing the second portion of the dowel to expand to its initial, relaxed condition radially outwardly into the second hole portion;
• and providing a plug which is inserted into the bore at the expanded second portion so as to provide a head of the plug at the second portion so that the second portion is prevented by the head from being compressed radially inwardly.

A method of fastening a dowel to a first and a second part of a solid material comprising:

• providing a first part of the solid material having an outside surface thereof;
• drilling a blind hole in the outside surface of the first part, the blind hole having a first hole portion thereof adjacent the outside surface, which has an inside surface which is cylindrical, and a second hole portion spaced from the surface which has an inside surface which has a part thereof which is of a second diameter which is greater than the first diameter;
• providing a second part of the solid material having an outside surface thereof;
• drilling a blind hole in the outside surface of the second part, the blind hole having a first hole portion thereof adjacent the outside surface, which has an inside surface which is cylindrical, and a second hole portion spaced from the surface which has a part thereof which is of a second diameter which is greater than the first diameter;
• providing a dowel having a first end and a second end for cooperation respectively with the blind holes in the first and second parts, each end being shaped with a first portion and a second portion corresponding to the first and second hole portions respectively, the dowel being shaped and arranged such that, in an initial, relaxed condition of the dowel, the first and second portions of the dowel each have an outside surface which is shaped to co-operate with the inside surface of the first and second portions of the hole;
• the dowel having a cylindrical bore therealong;
• the dowel being formed so that the second portion of each end is defined by a plurality of angularly separated parts allowing the second portion of each end to be compressed radially inwardly;
• providing an elongate plug member for extending along the full length of the dowel;
• providing on the plug member a first head at one end for insertion into the cylindrical bore at a respective second portion of one end of the dowel, a second head at an opposed end for insertion into the cylindrical bore at a respective second portion of the other end of the dowel, the heads each having an outer diameter matching that of the cylindrical bore, and a portion between the heads which is of reduced transverse dimensions relative to the diameter of the heads;
• compressing the second portion of the first end radially inwardly so that the second portion is substantially cylindrical with a diameter substantially equal to the first diameter;
• with the second portion of the first end compressed, inserting the first end of the dowel into the blind hole in the first part through the outside surface;
• allowing the second portion of the first end of the dowel to expand radially outwardly into the second hole portion of the first part;
• locating the plug member in the dowel such that one of the heads is located inside the bore in the dowel spaced axially from the respective second portion at the first end of the dowel and the other of the heads is located outside the dowel beyond the second end thereof;
• compressing the second portion of the second end radially inwardly so that the second portion is substantially cylindrical with a diameter substantially equal to the first diameter;
• with the second portion of the second end compressed, causing insertion of the second end of the dowel into the blind hole in the second part through the outside surface and allowing the second portion of the second end of the dowel to expand radially outwardly into the second hole portion of the second part;
• said insertion causing movement of the plug member axially relative to the dowel such that the first and second heads each simultaneously move to a position inside the respective second portion of the first and second ends so that each second portion is prevented from being compressed radially inwardly.