US 6,644,967 B2Granted

Process for making an expansion screw for orthodontics and screw thus made

AssigneeLeone S.P.A.

InventorsPaolo Ceppatelli, Maurizio Dolfi, Gabriele Scommegna

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Abstract

The present invention refers to a process for making an expansion screw and a screw thus made; the expansion screw (100, 100′) has two bodies (1, 2) that can be spaced apart by acting on the driving portion (6) of a double screw (3) housed within threaded central bores (30) provided in the two bodies (1, 2); each of the bodies (1, 2) has at least one bore (5, 50) parallel to the threaded bore; also provided is at least a hollow cylindrical guide (9) housed within a corresponding pair of parallel bores (5, 50) disposed on the two bodies (1, 2) in facing relationship; inserted in each guide (9) is a pin (4) for sliding therein; each guide (9) is fixed to one of the bodies, while the relevant pin (4) held therein is fixed to the other body, and the sliding of the pin (4) relative to the guide (9) takes place with friction owing to the force exerted upon assembly.

Claims16

Dependent claims

A process for making an orthodontic expansion screw, the process comprising the steps of:

forming two main bodies each with a threaded bore and a parallel bore parallel to the threaded bore;
providing a double screw with a driving portion, the double screw having first and second spindles respectively fitting into a respective one of said threaded bores;
providing a guidepin disposed coaxial to each said parallel bore, said guide pin having a leading end and a trailing end;
disposing the two bodies in facing relationship so as to align opposite parallel bores by screwing the double screw within the corresponding threaded bores to connect the two bodies to each other to provide facing walls of the two bodies and to provide opposite outer walls of the two bodies;
inserting into the aligned opposite bores a hollow cylindrical guide having a leading end and a trailing end, an outer diameter of the guide pin being slightly greater than a leading end inner diameter of the hollow cylindrical guide;
fixing the trailing end of the hollow cylindrical guide to one of said bodies at or adjacent to the outer wall of said one of said bodies;
inserting the guide pin into the hollow cylindrical guide through the cylindrical guide trailing end and positioning the leading end of the guide pin in correspondence to the leading end of said hollow cylindrical guide and pushing the leading end of the guide pin through the leading end inner diameter of said hollow cylindrical guide by the application of force to overcome the interference due to a difference of the respective diameters;
and
fixing the leading end of the guide pin to the other of said bodies at or adjacent to the outer wall of said other of said bodies.

6 more elements

An orthodontic expansion screw comprising:

two main bodies each having a threaded central bore and a parallel bore, parallel to said central bore;
a double screw with a driving portion and spindles, each of the spindles engaging a respective one of said threaded bores of said two main bodies;
a guide pin disposed coaxial to each said parallel bore of said two main bodies;
a hollow cylindrical guide disposed within said parallel bore of one of said two main bodies and fixed to said one of said two main bodies and freely extendable through said parallel bore of the other of said two main bodies, said guide pin being inserted with an interference fit into said hollow cylindrical guide wherein an outer diameter of said guide pin is larger than an inner diameter of at least a portion of said hollow cylindrical guide prior to insertion to provide frictional contact between an outer surface of said guidepin and an inner surface of said portion of said hollow cylindrical guide, said guide pin being fixed to said other of said two main bodies.

1 more element

An orthodontic expansion screw comprising:

a first body having a threaded central bore and a parallel side bore, parallel to said central bore;
a second body having a threaded central bore and a parallel side bore, parallel to said central bore;
a double screw with a driving portion and a first spindle engaging said first body threaded bore and a second spindle engaging said second body threaded bore wit said first body and said second body having facing sides;
a guide pin disposed coaxial to each of said first body parallel side bore and said second body parallel side bore;
a hollow cylindrical guide disposed within said first body parallel side bore and fixed to said first body and freely extendable through said second body, said guide pin being inserted with an interference fit into said hollow cylindrical guide wherein an outer diameter of said guide pin is larger than an inner diameter of at least a portion of said hollow cylindrical guide prior to insertion to provide frictional contact between an outer surface of said guide pin and an inner surface of said portion of said hollow cylindrical guide, said guide pin being fixed to said second body, at least one of said first body parallel side bore and said second body parallel side bore having a constant diameter and the other of said first body parallel side bore and said second body parallel side bore having a varying diameter with a constant diameter first section extending a predetermined length and a second section, opposite to said first section, with a smaller minor diameter, said second section being opposite said facing sides.

2 more elements

Dependencies are inferred from the claim text.