AN EXTENSION DRIVE MECHANISM FOR INTRAMEDULLARY EXTENSION NAILS

Abstract

An extension drive mechanism which enables the intramedullary nails used in the orthopedic surgery in the bone extension nail systems to extend and shorten in the application area and enables the bone to extend or shorten in a controlled manner.

Claims

1. An extension drive mechanism which enables intramedullary nails used in orthopedic surgery in bone extension nail systems to extend and shorten in the application area and enables the bone to extend or shorten in a controlled manner, the extension drive mechanism comprising: a direction control part which has direction control pins on its bottom surface, has rotational movement; a bearing housing which is located on the bottom surface of the direction control part and has internal movement surfaces on its internal surface; needle bearings which are located within each of the internal movement surfaces in the bearing housing in the form of at least pairs and whose axes are changed by moving by means of the direction control pins; bearing springs which are located between the needle bearings and enable the needle bearings to remain separate by pushing each other from the side surface; a drive shaft which is located between the needle bearings from the lower end of the bearing housing and rotates clockwise or counterclockwise by the needle bearings; and a gear motor which is engaged with the upper end of the direction control part and enables the direction control part to be driven in the selected rotational direction for rotating the drive shaft.

2. An extension drive mechanism according to claim 1, wherein the internal movement surface is a combination of three different circles with different centers placed at an angle of 120° to each other.

3. An extension drive mechanism according to claim 1, wherein the direction control part comprises direction control pins on its bottom surface which are located at 120° angle to each other and are located between the needle bearings in the form of pairs in the internal movement surfaces for moving the needle bearings.

4. An extension drive mechanism according to claim 1, comprising, a drive shaft which is located between said needle bearings and makes rotational movement by moving the needle bearings of the direction control pins in the direction control part driven by means of the gear motor, clockwise or counterclockwise.

5. An extension drive mechanism according to claim 1, comprising, a bearing protection cover which is engaged to the bottom surface of said bearing housing and prevents the bearing springs to come out of the bearing housing by means of the needle bearings.

Description

FIGURES CLARIFYING THE INVENTION

[0025] FIG. 1: is the exploded perspective view of the inventive extension drive mechanism.

[0026] FIG. 2: is the front view of the bearing housing of the inventive extension drive mechanism.

[0027] FIG. 3: is the perspective view of the inventive extension drive mechanism.

[0028] FIG. 4: is the sectional view of the inventive extension drive mechanism.

DESCRIPTION OF THE PART REFERENCES

[0029] 10. Direction control part [0030] 11. Direction control pin [0031] 20. Bearing housing [0032] 21. Internal movement surface [0033] 30. Needle bearing [0034] 40. Bearing spring [0035] 50. Bearing protection cover [0036] 60. Drive shaft [0037] 70. Gear motor

DETAILED DESCRIPTION OF THE INVENTION

[0038] In this detailed description, the preferred alternatives of the inventive extension drive mechanism is described only for clarifying the subject manner such that no limiting effect is created.

[0039] In FIG. 1, the exploded perspective view of the inventive extension drive mechanism is given. Accordingly, the extension drive mechanism mainly comprises the following; a direction control part (10) which has direction control pins (11) on its bottom surface located at 120° angles to each other, has rotational movement, a bearing housing (20) which is located on the bottom surface of the direction control part (10) and has an internal movement surface (21) whose internal surface is located with 120° angle and is formed from three circles with different centers, needle bearings (30) which are located within each of the internal movement surfaces (21) in the bearing housing (20) in the form of at least pairs and whose axes are changed by moving by means of the direction control pins (11), bearing springs (40) which are located between the needle bearings (30), a bearing protection cover (50) which is engaged to the bottom surface of said bearing housing (20), a drive shaft (60) which is located between the needle bearings (30) from the lower end of the bearing housing (20) and rotates clockwise or counterclockwise, a gear motor (70) which is engaged with the upper end of the direction control part (10) and enables the direction control part (10) to be driven in the selected rotational direction for rotating the drive shaft (60).

[0040] The direction control part (10) on its lower surface has direction control pins (11) which are located at 120° angles to each other. The bearing housing (20) is connected to the bottom surface of the direction control part (10). As can be seen in FIG. 2, the internal surface of the bearing housing (20) has an internal movement surface (21) which is the combination of three different circles with different centers placed at an angle of 120° to each other.

[0041] There are needle bearings (30) within each of the internal movement surfaces (21) in the bearing housing (20), in the form of pairs and 6 in total. Said needle bearings (30) remain parallel to each other in the bearing housing (20) in the axes of their own internal movement surfaces (21). Bearing springs (40) are located between the needle bearings (30) and the needle bearings (30) which are in the form of pairs within the internal movement surfaces (21) are provided to remain separate by pushing each other from the side surface.

[0042] In order to change the operational axes of the needle bearings (30), direction control pins (11) in the direction control part (10) located on the upper surface of the bearing housing (20) is located between the needle bearings (30) which are available in the form of pairs in the internal movement surfaces (21) in the bearing housing (20).

[0043] The needle bearings (30) move in the internal movement surfaces (21) by means of the direction control pins (11) which are located on the bottom surface of the direction control part (10) and can move clockwise or counterclockwise on the central axis. Said direction control part (10) can be able to move with an angle of ±5° to ±10° clockwise or counterclockwise on the centra I axis. The direction control part (10) which is engaged with the bearing housing (20) at its bottom end receives its rotational motion from the gear motor (70) which is engaged to its upper end.

[0044] The bottom surface of the bearing housing (20) is closed with the bearing protection cover (50) which prevents the bearing springs (40) to come out of the bearing housing (20) by means of the needle bearings (30).

[0045] A drive shaft (60) is located on the center of the bearing housing (20) such that it is located in the lower end of the bearing housing (20). Said drive shaft (60) can rotate clockwise or counterclockwise depending on the movement of the needle bearings (30) within the bearing housing (20).

[0046] The operation principle of the extension drive mechanism subject to the invention seen in FIG. 3 is as follows;

[0047] Said direction control part (10) is moved with an angle of ±5° to ±10° clockwise or counterclockwise by means of the gear motor (70). Depending on the rotational movement of the direction control part (10), also the directions control pins (11) which are located between the needle bearings (30) available in the form of pairs within the internal movement surfaces (21) in the bearing housing (20) move in the same manner.

[0048] The axes of the needle bearings (30) change with their movement in the internal movement surfaces (21) depending on the rotational movement of the direction control pins (11). The needle bearings (30) whose axes change in the internal movement surfaces (21) rotate the drive shaft (60) in the rotational direction.

[0049] As can be seen in FIG. 4, in case the direction control pins (11) are in the middle point of each needle bearing (30) pair namely at 0°, the drive shaft (60) cannot move in both directions.