CN2358847Y - Bone screw - Google Patents

Abstract

The utility model discloses a medical appliance used in the bone injury departments in hospitals, particularly a bone setting nail. The bone setting nail is composed of a reverse frustum-shaped screw cap of which the surface is in the shape of a convex arc, a screw rod core, right-angled triangle screw threads on the screw rod core and a screw tip. The screw rod core is in the shape of a cone. The outer circles of screw threads on the screw rod core are in the shape of a cylinder except screw threads on the screw tip. The combined part of the screw rod core and the screw cap is circular arc connection. The screw threads arranged from the tip to the bottom of the screw rod core of the bone setting nail are in the shape of gradually changing from a right-angled triangle to a right-angled trapezoid. Under the condition of the same diameter and length, the screw has high strength. When used, the bone setting nail does not easily loosen. The combined part of the screw cap and the screw rod core is not easily broken. Due to the adoption of the shape of screw threads, the bone setting nail is caused to be more and more tight, and thus, the bone setting nail dose not easily loosen.

Description

The synthetism nail

This utility model belongs to securing member, relates in particular to the synthetism nail that is used for medical orthopedics department.

At present for fracture patient, bone fracture person especially, hospital's orthopedics department generally all is to adopt blade plate and synthetism nail, and synthetism is followed closely blade plate and bone fixation together.Because man-hour is wanted back chipping adding in the screw cap of synthetism in the past nail and screw rod core joint portion, makes the joint portion form wedge angle; The screw rod core of this screw all is consistent near the part of tip with root diameter (RD), and in use, the place of the stressed maximum of whole screw is at root, and owing to said structure, root is easy to generate stress concentration and makes screw extraction.In addition, the form of thread tip on the screw rod core is consistent with root, all is right angled triangle; So after screw was screwed into bone, the screw thread of its root was stressed very little, in use, make screw loosening easily, finally make between blade plate and the bone and produce displacement.Being easy to a blade plate or synthetism nail like this fractures.

The purpose of this utility model is: a kind of synthetism nail is provided, under its diameter and the length situation identical with existing synthetism nail, has higher-strength, and in use be not easy to become flexible.

For achieving the above object, medical synthetism nail described in the utility model, be to make by corrosion-resistant metal materials, it is made up of right angled triangle screw thread and screw tip on inversed taper platform shape nut, screw rod core, the screw rod core, the screw rod core is cone, except that the screw thread at screw tip place, the screw thread cylindrical on the screw rod core is cylinder, and the screw rod core is that circular arc is connected with the joint portion of nut.

Further technical scheme is followed closely in described medical synthetism: the rectangular triangle of screw thread on the screw rod core of described synthetism nail from the tip to the root carries out the transition to right-angled trapezium gradually.

The further again technical scheme of described medical synthetism nail is: the inversed taper platform shape surface of described synthetism oncomelania medicated cap is the protrusion arcuation.

Advantage of the present utility model is: the nut and the screw rod core joint portion of synthetism nail are not easy to fracture, and it is tight more that the screw thread form of employing makes the synthetism nail go up more, is not easy to become flexible.

Below in conjunction with accompanying drawing this utility model is described in further detail:

Fig. 1 is the schematic appearance of this utility model synthetism nail;

Fig. 2 is the A-A profile of this utility model synthetism nail schematic appearance;

Fig. 3 is the screw thread form of this utility model synthetism nail root

Fig. 4 is the screw thread form of this utility model synthetism nail tip

In Fig. 1, Fig. 2, medical synthetism nail described in the utility model, be to make by corrosion-resistant metal materials, it is made up of screw thread 4 on inversed taper platform shape nut 1, screw rod core 6, the screw rod core 6 and screw tip 5, screw rod core 6 is cone, except that the screw thread at screw tip 5 places, the screw thread cylindrical on the screw rod core 6 is cylinder, and screw rod core 6 is that circular arc 3 is connected with the joint portion of nut 1.

In Fig. 2, Fig. 3, Fig. 4, the screw thread 4 on the screw rod core 6 carries out the transition to right-angled trapezium gradually from tip 5 to rectangular triangle the root circular arc 3.The inversed taper platform shape surface 2 of described synthetism oncomelania medicated cap 1 is the protrusion arcuation.

Claims (3)

1, a kind of medical synthetism nail, be to make by corrosion-resistant metal materials, it is made up of right angled triangle screw thread and screw tip on inversed taper platform shape nut, screw rod core, the screw rod core, it is characterized in that: the screw rod core is the circular cone stage body, except that the screw thread at screw tip place, screw thread cylindrical on the screw rod core is cylinder, and the screw rod core is that circular arc is connected with the joint portion of nut.

2, synthetism nail according to claim 1, it is characterized in that: the rectangular triangle of the screw thread on the screw rod core from the tip to the root carries out the transition to right-angled trapezium gradually.

3, synthetism nail according to claim 1 and 2, it is characterized in that: the inversed taper platform shape surface of nut is the protrusion arcuation.

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