Concrete screw

Claim 2

A screw for anchoring objects to a body of concrete, brick or like dusting materials by being threaded directly into a hole of a predetermined diameter in the body, said screw comprising an elongated body of lesser diameter than said hole and having a generally sharp end, an opposite end and a sharp-crested single thread having a maximum diameter larger than the diameter of the hole into which it is to be inserted and extending from adjacent one of said ends to adjacent the other of said ends, said thread having convolutions which are spaced from one another at their roots by a distance at least as great as the axial, crosssectional length of a single convolution, each convolution of said thread forming an acute angle with the axis of said screw such that said screw can be inserted into the hole only by applying a rotative force thereto, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately maximum diameter of said thread, said first region having at the maximum three convolutions of approximately maximum diameter, convolutions of said second region being of approximately maximum diameter, said third region having at least two convolutions, said convolutions of said third region having a maximum diameter lying in a range from the root diameter of said thread and a diameter less than the diameter of said hole, the diameter of the convolutions of said third region and the spacing therebetween comprising means for loosely storing the material removed from the wall of the hole during threading of said screw into the hole.

Claim 3

A screw for anchoring objects to concrete, brick or like dusting materials by being threaded directly into a hole of a predetermined diameter in said material, said screw comprising an elongated body of lesser diameter than said hole and having a generally sharp end, an opposite end and a sharp-crested single thread having a maximum diameter larger thAn the diameter of the hole into which it is to be inserted, and extending from adjacent one of said ends to adjacent the other of said ends, said thread having convolutions which are spaced from one another at their roots by a distance approximately as great as the axial, cross-sectional length of a single convolution, each convolution of said thread forming an acute angle with the axis of said screw such that said screw can be inserted into the hole only by applying a rotative force thereto, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately maximum diameter of said thread, said first region having at the maximum three convolutions of approximately maximum diameter, convolutions of said second region being of approximately maximum diameter, and said third region having at least two convolutions, said convolutions of said third region having a maximum diameter lying in a range from the root diameter of said thread and a diameter less than the diameter of said hole, the diameter of the convolutions of said third region and the spacing therebetween comprising means for loosely storing the material removed from the wall of the hole during threading of said screw into the hole.

Claim 4

A screw for anchoring objects to concrete, brick or like dusting materials by being threaded directly into a hole of a predetermined diameter in said material, said screw comprising an elongated body of lesser diameter than said hole and having a generally sharp end, an opposite end and a sharp-crested single thread having a maximum diameter larger thAn the diameter of the hole into which it is to be inserted, and extending from adjacent one of said ends to adjacent the other of said ends, said thread having convolutions which are spaced from one another at their roots by a distance approximately as great as the axial, cross-sectional length of a single convolution, each convolution of said thread forming an acute angle with the axis of said screw such that said screw can be inserted into the hole only by applying a rotative force thereto, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately maximum diameter of said thread, said first region having at the maximum three convolutions of approximately maximum diameter, convolutions of said second region being of approximately maximum diameter, and said third region having at least two convolutions, said convolutions of said third region having a maximum diameter lying in a range from the root diameter of said thread and a diameter less than the diameter of said hole, the diameter of the convolutions of said third region and the spacing therebetween comprising means for loosely storing the material removed from the wall of the hole during threading of said screw into the hole.

Claim 5

The combination according to claim 2 wherein the convolutions of said third region adjacent said second region increase in diameter from the diameter of said third region to the maximum diameter of the convolutions of said second region.

Claim 6

The combination according to claim 2 wherein the hole in the material has a predetermined depth and wherein the screw is intended to pass through a hole in a wall of an object located a predetermined distance above the surface of the material, said screw being of such axial length that at least four convolutions of said second region enter the hole in the material and engage the material defining the side of the hole.

Claim 7

In combination a body of concrete, brick or like dusting material having a hole of a predetermined diameter formed therein and a screw which may be threaded directly into the hole in said body, said screw comprising an elongated body having a generally sharp end, an opposite end adapted to receive a device for rotating said screw and a sharp-crested single case-hardened thread of a maximum diameter greater than the diameter of the hole and a root diameter less than the diameter of the hole, extending from adjacent one of said ends to adjacent the other of said ends, said screw having threads of a pitch such that the screw must be inserted into the hole by rotation, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately the maximum diameter of said thread, said first region having at the maximum three convolutions of approximately maximum diameter, the majority of said convolutions of said second region being of approximately maximum diameter, said third region having at least two convolutions, said convolutions having a maximum thread diameter lying in a range from the root diameter of said thread and a diameter greater than said root diameter and less than the diameter of the hole, said convolutions being spaced from one another by a distance such as to accommodate in loosely compacted form between the convolutions of said third region, the dust created by the convolutions of said first region during insertion of said screw in said body.

Claim 8

In combination a body of concrete, brick or like dusting material having a hole of a predetermined diameter formed therein and a screw which may be threaded directly into the hole in said body, said screw comprising an elongated body having a generally sharp end, an opposite end adapted to receive a device for rotating said screw and a sharp-crested single case-hardened thread of a maximum diameter greater than the diameter of the hole and a root diameter less than the diameter of the hole, extending from adjacent one of said ends to adjacent the other of said ends, said screw having threads of a pitch such that the screw must be inserted into the hole by rotation, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately the maximum diameter of said thread, said first region having at the maximum three convolutions of approximately maximum diameter, the majority of said convolutions of said second region being of approximately maximum diameter, said third region having at least two convolutions, said convolutions having a maximum thread diameter lying in a range from the root diameter of said thread and a diameter greater than said root diameter and less than the diameter of the hole, said convolutions being spaced from one another by a distance such as to accommodate in loosely compacted form between the convolutions of said third region, the dust created by the convolutions of said first region during insertion of said screw in said body.

Claim 9

The combination according to claim 5 wherein the volume of space defined between the convolutions of said second region of sAid screw and the wall of the hole in said body is such as to accommodate in generally loosely compacted form, the dust created by the convolutions of said second region upon insertion of said screw in said body.

Claim 10

In combination a body of concrete, brick or like dusting material having a hole of a predetermined diameter formed therein and a screw which may be threaded directly into the hole in said body, said screw comprising an elongated body having a generally sharp end, an opposite end adapted to receive a device for rotating said screw and a sharp-crested single case-hardened thread of a maximum diameter greater than the diameter of the hole and a root diameter less than the diameter of the hole, extending from adjacent one of said ends to adjacent the other of said ends, said screw having threads of a pitch such that the screw must be inserted into the hole by rotation, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately the maximum diameter of said thread, said first region having at the maximum two convolutions of approximately maximum diameter, the majority of said convolutions of said second region being of approximately maximum diameter, said third region having at least two convolutions, said convolutions having a maximum thread diameter lying in a range from the root diameter of said thread and a diameter greater than said root diameter and less than the diameter of the hole, said convolutions being spaced from one another by a distance such as to accommodate in loosely compacted form between the convolutions of said third region, the dust created by the convolutions of said first region during insertion of said screw in said body.

Claim 11

In combination a body of concrete, brick or like dusting material having a hole of a predetermined diameter formed therein and a screw which may be threaded directly into the hole in said body, said screw comprising an elongated body having a generally sharp end, an opposite end adapted to receive a device for rotating said screw and a sharp-crested single case-hardened thread of a maximum diameter greater than the diameter of the hole and a root diameter less than the diameter of the hole, extending from adjacent one of said ends to adjacent the other of said ends, said screw having threads of a pitch such that the screw must be inserted into the hole by rotation, said thread having three distinct regions arranged along the axis of said screw, a first region adjacent said sharp end, a second region adjacent said opposite end and a third region lying between said other regions, said first region including a plurality of convolutions increasing from a minimum diameter at said pointed end to approximately the maximum diameter of said thread, said first region having at the maximum two convolutions of approximately maximum diameter, the majority of said convolutions of said second region being of approximately maximum diameter, said third region having at least two convolutions, said convolutions having a maximum thread diameter lying in a range from the root diameter of said thread and a diameter greater than said root diameter and less than the diameter of the hole, said convolutions being spaced from one another by a distance such as to accommodate in loosely compacted form between the convolutions of said third region, the dust created by the convolutions of said first region during insertion of said screw in said body.