ES2786104A1 - Angled Permanent Contact Screw (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

The present invention refers to a connection system between two pieces; a driving tool, and a dental prosthesis fixation screw. This connection system is designed to ensure a perfect coupling between the tool and the screw head, even when the axes of both components are not completely aligned, allowing inclinations of the tool, with respect to the screw head axis, of up to 30º. The special design of the geometry of the connection between tool and screw allows that the same torque can be applied regardless of the angle formed by the axis of the screw and the axis of the driving tool. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Permanent contact connection system between drive tool and fixation screw for dental prostheses

Technical sector

The field of application of the present invention is framed within the field of dentistry - implantology, focusing specifically on the field of dental implants and in particular on structures made by conventional casting, subtraction (CAD-CAM milling) or addition (SLM , DMLS), or mass-produced parts. In any case, all of them are screwed onto dental implants.

Object of the invention

The present invention refers to a screw, and a tool, that form a fixing system to be used in structures made by conventional casting, subtraction (CAD-CAM milling) or addition (SLM, DMLS), or parts manufactured in series. Said structures are used in the manufacture of prostheses on dental implants.

The object of the present invention refers to a connection system between two pieces; a driving tool, and a dental prosthesis fixation screw. This connection system is designed to ensure a perfect coupling between tool and screw head, even when the axes of both components are not fully aligned, allowing inclinations of the tool, with respect to the screw head axis, of up to 30 °. The special design of the geometry of the connection between tool and screw allows that the same torque can be applied regardless of the angle formed by the axis of the screw and the axis of the driving tool.

The system incorporates advantages to improve the security of the screwing system, at the same time that it allows correcting a large number of problems; increase durability, provide solutions to solve aesthetic and functional problems, decrease the probability that the tool will disengage from the screw head during use, and increase flexibility of use.

Background of the invention

Currently there are systems that allow the screwing of a fixing screw when the drive axis of the tool and the screw are not aligned. But none of them rely on permanent contact between the screw head and the driving tool. Permanent contact occurs thanks to a particular design of the geometry of the connection between the screw head and the driving tool. And it will be explained in detail later.

This permanent contact ensures that the same torque can be applied regardless of the angle between the screw axis and the driving tool axis. This effect does not occur in any of the previously patented systems due to the fact that they are provided with connection geometries between tool and screw different from that of the present invention. These patents are cited below.

1.- Hexalobular system derived from a normalized torch system; Presented in patent ES 2 665548 T3. Wherein claim 1 of said patent states the following:

“Claim 1. Screw ( P) for a dynamic dental implantology abutment, the screw ( P) comprising a head ( P-1, P-11) with a cylindrical shape and a body that has a thread and a hemispherical shape in its part lower, the head ( P-1, P-11) of the screw ( P) having an internal part ( P-1-A, P-11-A) with a hexalobular female shape, with a circular center and six depressions and six summits alternated on the periphery, the screw ( P) being characterized in that the internal part with a hexalobular shape is presented according to the ISO 10664 standard, with

to. an external diameter ( DE-1) ranging from 1.8mm to 2.7mm in diameter,

b. a larger internal diameter ( DIMA-1) ranging from 1.3 to 2.4 mm,

c. a smaller internal diameter ( DIME-1) ranging from 1.0 to 2.0 mm,

d. an internal height ( AI-1) ranging from 0.5 to 1.5 mm,

and. a radius of depression ( RDP-1) ranging from 0.15 to 0.35 mm,

F. a radius of the summit ( RCP-1) varies from 0.15 to 0.35 mm,

so the internal hexalobe shape allows a 0 ° to 35 ° tilt for application of torque with a screwdriver. "

2. - Concave-convex curved recessed hexalobular system; Presented in patent ES 2577 509 T3. Wherein claim 2 of said patent states the following:

"Claim 2. Screw head ( 1) for use with a coupling tool according to claim 1, said head comprises a recess ( 3) having a bottom and a plurality of curved-convex axial projections ( 4) with a section decreasing towards the interior of the recess ( 3) and ending just before said bottom, said axial projections ( 4) are circumferentially separated from each other by a distance greater than the distance of the maximum width of said axial projections ( 4). "

3. - Hemispherical octagonal system; Presented in patent ES 2577509 T3. Wherein claims 7 and 3 of said patent state the following:

"Claim 3. The screwdriver according to claim 1 or 2, wherein the polygonal shape is an octagonal shape."

"Claim 7. A screw member for attaching dental structures to dental implants, comprising a threaded portion ( 31) at a first end and a screw member head ( 32) with a recess ( 33) at a second end to receive a tip portion of the screwdriver according to any of claims 1 to 6, characterized in that said recess has a substantially polygonal shaped cross-section in a radial plane with at least first and second diagonals ( 38, 39), which are extend perpendicularly to two opposite sides of the polygon, respectively, where said first diagonal ( 38) is larger than said second diagonal ( 39), where the relationship between the first diagonal ( 38) and the second diagonal ( 39) are selected in the range 1.2 to 1.3. Four. Five"

4. - Conical polygonal system; Presented in patent ES 2 551 863 T3. Wherein claim 3 of said patent states the following:

"Claim 3. A combination according to any preceding claim, wherein the apical end of the screw hole is conical ( 330), having the widest point at the apical end of the recesses ( 350)."

5.- Polygonal system based on the clearance between tool and screw: Presented in patent PCT / ES2016 / 000104. Wherein claim 1 sets forth the following:

"Claim 1. Thyme and drive tool for dental implantology; comprising: one of them, a toothed head ( 21). Rounded, with a series of teeth ( 22) distributed peripherally; and the other, a prismatic housing ( 13) with a plurality of longitudinal channels ( 14) distributed in its periphery; the number of channels being equal to or greater than the number of teeth ( 22) of the toothed head ( 21) and preferably a multiple thereof; characterized in that said longitudinal channels ( 14) have a width greater than the corresponding teeth ( 22), so that in the position of engagement of the screw with the driving tool, the toothed head ( 21) is enabled for a relative rotation of a determined amplitude ( a) within the prismatic housing ( 13) and with respect to the geometric axis of the thyme, between: "

Explanation of the invention

The present invention has as its object a driving tool for use with a screw head, which allows actions on the screw head, both in screwing and unscrewing operations, even when the tool is not aligned with the axis of said screw. head, being able to form with the same angles of up to 30 °.

Another object of the invention is to achieve a screw head capable of being actuated with a driving tool that allows the same tightening torque to be applied regardless of the angle formed by the axis of the screw head and the axis of the tool, both for the threaded and unscrewed, without risk of damage to these components.

These components are described below and how the interaction between them occurs when working together:

Screw head:

The screw head comprises a drive geometry that is made up of:

- A cylindrical hole, arranged coaxially with the axis of the screw (1.1).

- Some tetrahedral cuts (1.2), arranged perimeter around the coaxial hole (1.1), and are parallel to the axis of the screw head.

Drive tool:

The contact geometry of the driving tool with the screw head is formed by the intersection of three geometric surfaces:

- A cylinder (3.1): this forms the main core of the tool.

- A cross (3.2): it is formed by four rods (3.3), which are inscribed inside the cylinder that forms the main core of the tool. The center of the cross coincides with the axis of the cylinder of the main tool core.

- A sphere (3.4): this surface delimits the extension of the rods that make up the cross. The center of the sphere coincides with the center of the cross.

Interaction between drive tool and screw head:

For a better understanding of the working mode between tool and screw, the following premises must be taken into account:

- The center of rotation about which misalignment occurs between the tool axis (6.2) and the screw head axis (6.1) is the center of the cross (3.2), which is the same as that of the sphere that defines the length of the stems.

- When a 360 ° rotation occurs around the axis of the screw (6.1) of a tool that forms a certain angle with it (6.5), a precession movement occurs.

- This precessional movement is described by four singular situations located at 0 °, 90 °, 180 ° and 270 ° with respect to the origin of rotation. The transition from one singular position to another describes the movement of the point of contact of the shanks of the tool cross (3.3) along the tetrahedral cuts of the screw head (1.2).

- The mechanical interference between the tool (6.4) and the screw head (6.3) is what produces the transmission of movement.

- The area of the mechanical interference section is proportional to the maximum allowable tightening torque of the system.

Thus, from the foregoing, the system's working mode comprises the following characteristics:

The area of the contact surface between tool (6.4) and screw (6.3) throughout a complete 360 ° rotation cycle is always the same. Regardless of the angle between the screw and the tool.

Throughout a complete 360 ° rotation cycle, there is only one displacement of the contact point between tool (6.4) and screw (6.3). That is, the shanks of the cross of the tool (3.3) move along the tetrahedral grooves of the screw (1.2). It should be noted that in none of the previously patented systems within the scope of implant dentistry does it meet the work characteristics described here. The working mode of these elements is based on the operation of the power transmission of the Cardan joint. This type of transmission occurs without any gaps between the elements that make up the transmission.

The mechanical part on which this type of transmission is based is the Cardan crosshead (figure 7). It is important to note that the intrinsic figure that defines the geometry of the driving tool is said crosshead (figure 7). For constructional reasons in manufacturing and to guarantee mechanical resistance, the final geometry resulting from the tool comprises a cross (3.2), where the shanks of the cross (3.3) have a substantially rhomboidal section, and are delimited in their length by a spherical surface (3.4). But in reality all this geometry is inscribing a Cardan crosshead inside it. Thanks to this, Movement kinematics ensures that no play occurs between the transmitting and transmitted part of the movement.

All the patents filed above have in common that they allow misalignment between the axis of the tool and the screw thanks to a mechanical backlash that allows such misalignment. And this clearance varies depending on the angle of misalignment. So neither of them can guarantee permanent contact between the tool and screw intersection surfaces. That is, none of the above inventions can guarantee that the same torque can be applied at any angle of misalignment. For this reason, the connection system between tool and screw presented here is different, and is called:

"Permanent contact connection system between drive tool and fixing screw for dental prostheses".

Brief description of the drawings

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part of said description where, for illustrative purposes, and not limiting, what has been represented following:

Figure 1: Shows the plan and elevation views of the screw head, where:

1.1. - Sample cylindrical bore.

1.2. - Shows tetrahedral sections.

Figure 2: Shows the perspective view of the screw head.

Figure 3: Shows the plan and elevation views of the tip of the drive tool, where:

3.1. - Shows the cylinder that forms the main body of the tool.

3.2. - Shows the cross inscribed on the cylinder.

3.3. - Shows the stems of the cross.

3.4. - Shows the sphere that defines the length of the shanks of the cross.

Figure 4: Shows a perspective representation of the driving tool.

Figure 5: Shows a perspective representation of the coupling between the driving tool and the screw head.

Figure 6: Shows a representation of the cross section of the coupling between the driving tool and the screw head, where:

6.1. - Shows the axis of the screw head.

6.2. - Shows the axis of the driving tool.

6.3. - Shows the cross section of the screw head.

6.4. - Shows the cross section of the drive tool.

6.5. - Shows the misalignment angle between the axis of the head of the screw and the axis of the driving tool.

Figure 7: Shows three elevation geometric representations of:

7.1.- Cardan crosshead superposition, with the drive tool (grated surface).

7.2.- Cardan crosshead.

7.3.- Drive tool.

Figure 8: Shows a perspective representation of the Cardan crosshead.

Claims (2)

1. Actuation tool (figure 4) for use with a screw head (figure 2), said tool comprises a shank (3.1) characterized by a frusto-conical surface, an adjacent cross-shaped protrusion (3.2), where the The rods of the cross (3.3) have a substantially rhomboidal section, and are delimited in their length by a spherical surface (3.4), so that the geometric center of the cross and the spherical surface coincide in position, and these at their once they are located on the axis of the frustoconical surface of the tool. 2. Screw head (figure 2) for use with a driving tool (figure 4) according to claim 1, said head comprises a recess characterized in that it has a frusto-conical hole in the upper part, and in its lower part a hole cylindrical (1.1) with four tetrahedral cuts (1.2), parallel to the axis of the hole and located on its perimeter, separated from each other by an angle of 90 °, arranged together in the shape of a cross.