CN204484286U - A kind of for the screw thread in pedicle screw - Google Patents
A kind of for the screw thread in pedicle screw Download PDFInfo
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- CN204484286U CN204484286U CN201520029482.3U CN201520029482U CN204484286U CN 204484286 U CN204484286 U CN 204484286U CN 201520029482 U CN201520029482 U CN 201520029482U CN 204484286 U CN204484286 U CN 204484286U
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- plush copper
- screw thread
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Abstract
The utility model discloses a kind of for the screw thread in pedicle screw, described screw thread comprises the external screw thread on the female thread that is positioned at pedicle nail afterbody and nut corresponding with it, the thread of described female thread has upwards or/and downward plush copper and in convex hook shape, described externally threaded thread has corresponding with the thread of described female thread downwards or/and plush copper upwards, same in convex hook shape, and described female thread and described externally threaded all bent angles are fillet.When tightening, between described female thread and described external screw thread, there is space, thus there is the effect be better locked; The relative position of internal and external threads can be controlled better, reduce difficulty of processing, improve tolerance and coordinate control accuracy; When screw thread generation non-horizontal contacts, reduce thread root stressed, reduce the problem that knuckle place stress is concentrated.
Description
Technical field
This utility model relates to technical field of medical instruments, is specifically related to a kind of screw thread for pedicle screw afterbody.
Background technology
Common rectangular thread, triangle thread, trapezoidal thread, saw-tooth thread design, and when internal and external threads is locked, external screw thread and female thread produce radial component mutually.Concerning external screw thread, it is subject to the radial distracting force that female thread produces; Internal threads, its externally threaded radial compression power be subject to.Therefore can find out, female thread sidewall has separately trend, and distance increases, and is unfavorable for the locking of internal and external threads and fixes.
And when internal and external threads is subject to radial pressure, common screw thread design can cause the stress of screw thread to concentrate on thread root, easily produce screw thread fracture.
In addition, in female thread and externally threaded mutual tolerance fit, desirable tolerance fit makes internal and external threads coaxial, and circumferential direction internal and external threads contact area is impartial.Regular screw threads design is except improving the machining accuracy of internal and external threads entirety, and be difficult to accurately control tolerance fit, easily cause internal and external threads tolerance excessive, locking effect is undesirable; Or internal and external threads bias coordinates, make screw thread contact area large, another side contact area is little, and unbalance stress causes thread looseness.
The patent No. is: 200910047307.6, and the applying date is the patent of invention of 2009-03-10, discloses a kind of locking screw thread of pedicle screw afterbody.Its design screw thread design reduces the effect of screw head tension force when can play locking, the inner core of nut is convenient to locking and the removal of nut, is avoided stripped thread and nut to expand.But when internal and external threads non-horizontal contacts, face originally-face contact becomes line-face contact, and contact position is uncertain, causes, in the stressed increase in knuckle place, easily causing thread abrasion, or damage inactivation.Knuckle place is that right angle then more easily causes stress to be concentrated, and thread damage occurs.
Utility model content
Because the above-mentioned defect of prior art, technical problem to be solved in the utility model is: when screw thread generation non-horizontal contacts, the problem that the stressed increase of solution thread root, knuckle place stress are concentrated.
For achieving the above object, this utility model provides a kind of for the screw thread in pedicle screw, described screw thread comprises the external screw thread on the female thread that is positioned at pedicle nail afterbody and nut corresponding with it, the thread of described female thread has upwards or/and downward plush copper and in convex hook shape, described externally threaded thread has corresponding with the thread of described female thread downwards or/and plush copper upwards, same in convex hook shape, and described female thread and described externally threaded all bent angles are fillet.
Preferably, when tightening, between described female thread and described external screw thread, there is space.
In a kind of preferred implementation of the present utility model, the thread of described female thread is lower convex hook-type, described lower convex hook has plush copper, the second longitudinal edge and the second widthwise edge under the first widthwise edge, the first longitudinal edge, arc successively, is spaced apart the 3rd longitudinal edge between the lower convex hooks of two row; The shape of described external screw thread thread is epirelief hook-type, the 4th longitudinal edge is spaced apart between two row epirelief hooks, described epirelief hook is corresponding with described lower convex hook, there is plush copper, the 6th longitudinal edge and the 4th widthwise edge successively on the 3rd widthwise edge, the 5th longitudinal edge, arc, and the bent angle between described each widthwise edge and longitudinal edge, between longitudinal edge and arc plush copper is fillet.Preferably, when tightening, under arc between plush copper and the 3rd widthwise edge, and arc is line-face contacts between plush copper with the second widthwise edge.
In another kind of preferred implementation of the present utility model, described female thread and externally threaded thread are upper and lower convex hook-type, described upper and lower convex hook to have on the first widthwise edge, the first longitudinal edge, arc plush copper, the 3rd longitudinal edge, the second widthwise edge under plush copper, the second longitudinal edge, arc successively, be spaced apart the 4th longitudinal edge between the upper and lower convex hook of two row, and the bent angle between described each widthwise edge and longitudinal edge, between longitudinal edge and arc plush copper is fillet.Preferably, when tightening, under the arc of female thread between plush copper and externally threaded first widthwise edge, and the arc of female thread is line-face contacts between plush copper with externally threaded second widthwise edge.
Further, in above preferred embodiment, described widthwise edge and longitudinal edge can be all the combination of straight line, curve or straight line and curve.
Preferably, in described screw thread, the scope of the angle of contingence of the junction of all straight lines and curve all (does not comprise end points) between 0 ~ 15 °.
In this utility model, when described female thread and described external screw thread are tightened, between screw thread, there is space, in the course of processing, as long as control the size of female thread arc plush copper and external screw thread arc plush copper, just indirectly can control space between the two, play the effect controlling internal and external threads relative position.In addition, this line-face contact relation between upper and lower plush copper and widthwise edge adds the pressure acted on widthwise edge, can play the effect be locked further.
When female thread or external screw thread processing occur eccentric, only need control the distance size between upper and lower plush copper and corresponding longitudinal edge, the length of thread can be controlled, thus make stress equalization on the thread of internal and external threads both sides.
When female thread contacts with external screw thread generation non-horizontal, owing to just requiring that when designing material can sustain the stress of a face or the contact generation of line face, and the place contacted with thread at turning carries out is fillet design, add the space between internal and external threads, thus stress concentration phenomenon can be made to be down to minimum degree.
This utility model has following Advantageous Effects:
1, there is the effect be better locked;
2, the relative position of internal and external threads can be controlled better, reduce difficulty of processing, improve tolerance and coordinate control accuracy;
3, when screw thread generation non-horizontal contacts, reduce thread root stressed, and reduce the concentrated problem of knuckle place stress.
Be described further below with reference to the technique effect of accompanying drawing to design of the present utility model, concrete structure and generation, to understand the purpose of this utility model, characteristic sum effect fully.
Accompanying drawing explanation
Fig. 1 is the longitudinal cross-section schematic diagram of convex hook and external screw thread epirelief hook under this utility model preferred embodiment female thread;
Fig. 2 is the perspective view of this utility model preferred embodiment female thread;
Fig. 3 is the externally threaded perspective view of this utility model preferred embodiment;
Fig. 4 is the structural representation after the assembling of this utility model preferred embodiment internal and external threads;
Structural representation when Fig. 5 is eccentric about this utility model external screw thread;
Structural representation when Fig. 6 is eccentric about this utility model female thread;
Fig. 7 is the longitudinal cross-section schematic diagram that another preferred embodiment female thread of this utility model and external screw thread are upper and lower convex hook.
Detailed description of the invention
Be a kind of preferred embodiment of the present utility model as shown in figures 1-4, a kind of screw thread in pedicle screw provided in this preferred embodiment comprises the external screw thread on the female thread that is positioned at pedicle nail afterbody and nut corresponding with it, the shape of described female thread thread is lower convex hook-type, described lower convex hook 1 has successively and is spaced apart the 3rd longitudinal edge 16 under the first widthwise edge 11, first longitudinal edge 12, arc between plush copper 13, second longitudinal edge 14 and the lower convex hook 1 of the second widthwise edge 15, two row; The shape of described external screw thread thread is epirelief hook-type, the 4th longitudinal edge 21 is spaced apart between two row epirelief hooks 2, described epirelief hook 2 is corresponding with described lower convex hook 1, there is plush copper 24, the 6th longitudinal edge 25 and the 4th widthwise edge 26 successively on the 3rd widthwise edge 22, the 5th longitudinal edge 23, arc, and the bent angle between described each widthwise edge and longitudinal edge, between longitudinal edge and arc plush copper is fillet; In addition, when described female thread and described external screw thread are tightened, under arc between plush copper 13 and the 3rd widthwise edge 22, and arc is line-face contacts (corresponding to point cantact in Fig. 1) between plush copper 24 with the second widthwise edge 15.When therefore tightening, space is there is, in the course of processing, as long as the size of plush copper 13 and plush copper 24 on external screw thread arc under controlling female thread arc between described female thread and described external screw thread, just indirectly can control space between the two, play the effect controlling internal and external threads relative position.In addition, this line-face contact relation adds the pressure acted on the 3rd widthwise edge 22 and the second widthwise edge 15, can play the effect be locked further.
Further when internal and external threads is tightened, female thread is subject to the pulling force pointing to screw axle center, and has the trend of outer, makes external screw thread be subject to the pulling force in screw axle center dorsad; In this process, under female thread arc on the left side of plush copper 13 and external screw thread arc the right side of plush copper 24 mutually against, play the effect preventing external screw thread from deviating from.Meanwhile, under female thread arc on the left of plush copper 13 with plush copper 24 on external screw thread arc on the right side of interaction also shared the stress acting on external screw thread the 4th longitudinal edge 21 and the 3rd widthwise edge 22 junction.
Due to the impact of the factors such as the precision of process equipment, labour variance in the actual course of processing, the situation of tapped eccentric may be there is, when female thread or external screw thread processing occur eccentric, namely female thread or externally threaded side thread protrude more, and opposite side thread protrudes less (as shown in Figure 5 and Figure 6).Such as in Figure 5, on the right of external screw thread, thread is longer than left side thread, in order to make stress equalization on the screw thread of internal and external threads both sides, the distance size on arc between plush copper 24 and female thread second longitudinal edge 14 is controlled during processing, the length of thread can be controlled, the length of the second widthwise edge 15 or the 3rd widthwise edge 22 reduces, otherwise under arc on plush copper 13 or arc the size of plush copper 24 increase, to reach the object of both sides stress balance.
And regular screw threads are when above-mentioned bias occurs, because rectangular thread, triangle thread do not have the second longitudinal edge 14 and the 5th longitudinal edge 23, the 3rd longitudinal edge 16 and the 6th longitudinal edge 25 therefore can only be relied on to control the distance of internal and external threads.Cannot control further and remedial measure for above-mentioned situation.
Non-horizontal contact refers to that the horizontal thread of female thread and external screw thread thread non-horizontally contact, or the horizontal thread of external screw thread and female thread thread non-horizontally contact.For regular screw threads, the contact form of thread becomes a face or line face from plane-plane contact and contacts, add the stress of root part of screw tooth, owing to just only considering that when designing material can sustain the stress of plane-plane contact generation, therefore material likely destroys in this case.For the screw thread in this preferred embodiment, owing to just requiring that when designing material can sustain the stress of a face or the contact generation of line face, therefore, even non-horizontal contact, material also can bear stress in this case, is not damaged.Fillet design is carried out in the place contacted with thread at turning, reduce further the stress concentration phenomenon of root part of screw tooth.
In another kind of preferred implementation of the present utility model, described female thread and externally threaded thread are upper and lower convex hook-type, as shown in Figure 7, described upper and lower convex hook to have on the first widthwise edge 31, first longitudinal edge 32, arc plush copper 35, the 3rd longitudinal edge 36, second widthwise edge 37 under plush copper 33, second longitudinal edge 34, arc successively, be spaced apart the 4th longitudinal edge 38 between the upper and lower convex hook of two row, and the bent angle between described each widthwise edge and longitudinal edge, between longitudinal edge and arc plush copper is fillet; In addition, when described female thread and described external screw thread are tightened, under the arc of female thread between plush copper 35 and externally threaded first widthwise edge 31, and the arc of female thread is that line-face contacts between plush copper 33 with externally threaded second widthwise edge 37.
More than describe preferred embodiment of the present utility model in detail.Should be appreciated that those of ordinary skill in the art just can make many modifications and variations according to design of the present utility model without the need to creative work.Therefore, all technical staff in the art according to design of the present utility model on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment, all should by the determined protection domain of claims.
Claims (8)
1. one kind for the screw thread in pedicle screw, it is characterized in that, described screw thread comprises the external screw thread on the female thread that is positioned at pedicle nail afterbody and nut corresponding with it, the thread of described female thread has upwards or/and downward plush copper and in convex hook shape, described externally threaded thread has corresponding with the thread of described female thread downwards or/and plush copper upwards, same in convex hook shape, and described female thread and described externally threaded all bent angles are fillet.
2. as claimed in claim 1 for the screw thread in pedicle screw, it is characterized in that, when tightening, between described female thread and described external screw thread, there is space.
3. as claimed in claim 1 for the screw thread in pedicle screw, it is characterized in that, the thread of described female thread is lower convex hook-type, described lower convex hook has plush copper, the second longitudinal edge and the second widthwise edge under the first widthwise edge, the first longitudinal edge, arc successively, is spaced apart the 3rd longitudinal edge between the lower convex hooks of two row; The shape of described external screw thread thread is epirelief hook-type, the 4th longitudinal edge is spaced apart between two row epirelief hooks, described epirelief hook is corresponding with described lower convex hook, there is plush copper, the 6th longitudinal edge and the 4th widthwise edge successively on the 3rd widthwise edge, the 5th longitudinal edge, arc, and the bent angle between described each widthwise edge and longitudinal edge, between longitudinal edge and arc plush copper is fillet.
4. as claimed in claim 3 for the screw thread in pedicle screw, it is characterized in that, when tightening, under arc between plush copper and the 3rd widthwise edge, and arc is line-face contacts between plush copper with the second widthwise edge.
5. as claimed in claim 1 for the screw thread in pedicle screw, it is characterized in that, described female thread and externally threaded thread are upper and lower convex hook-type, described upper and lower convex hook to have on the first widthwise edge, the first longitudinal edge, arc plush copper, the 3rd longitudinal edge, the second widthwise edge under plush copper, the second longitudinal edge, arc successively, be spaced apart the 4th longitudinal edge between the upper and lower convex hook of two row, and the bent angle between described each widthwise edge and longitudinal edge, between longitudinal edge and arc plush copper is fillet.
6. as claimed in claim 5 for the screw thread in pedicle screw, it is characterized in that, when tightening, under the arc of female thread between plush copper and externally threaded first widthwise edge, and the arc of female thread is line-face contacts between plush copper with externally threaded second widthwise edge.
7. as described in any one of claim 3-6 for the screw thread in pedicle screw, it is characterized in that, described widthwise edge and longitudinal edge are the combination of straight line, curve or straight line and curve.
8. as claimed in claim 7 for the screw thread in pedicle screw, it is characterized in that, in described screw thread, the scope of the angle of contingence of the junction of all straight lines and curve is all between 0 ~ 15 °.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520029482.3U CN204484286U (en) | 2015-01-16 | 2015-01-16 | A kind of for the screw thread in pedicle screw |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520029482.3U CN204484286U (en) | 2015-01-16 | 2015-01-16 | A kind of for the screw thread in pedicle screw |
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| Publication Number | Publication Date |
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| CN204484286U true CN204484286U (en) | 2015-07-22 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201520029482.3U Active CN204484286U (en) | 2015-01-16 | 2015-01-16 | A kind of for the screw thread in pedicle screw |
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| CN (1) | CN204484286U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020224657A1 (en) * | 2019-05-09 | 2020-11-12 | The University Of Hong Kong | A novel thread design for bone screw |
-
2015
- 2015-01-16 CN CN201520029482.3U patent/CN204484286U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020224657A1 (en) * | 2019-05-09 | 2020-11-12 | The University Of Hong Kong | A novel thread design for bone screw |
| US11596459B2 (en) | 2019-05-09 | 2023-03-07 | The University Of Hong Kong | Thread design for bone screw |
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