TWI864546B - Screws for plastic materials - Google Patents

Abstract

The present invention provides a screw for use in plastic materials, comprising a head, a tip, a rod and a thread, wherein the thread surrounds the outer surface of the rod in a spiral protrusion, the ridge section of the thread is in an arc shape, the intersection of the thread and the rod is in a concave arc shape, the curvature of the concave arc shape of the thread forward surface is smaller than the curvature of the concave arc shape of the thread reverse surface, the concave arc shape of the thread reverse surface is connected to the arc shape of the thread ridge line, and the reverse direction of the thread is The surface of the screw thread and the rod body form a concave arc surface that is approximately perpendicular to each other. The other side of the arc shape of the thread ridge line extends to connect with the concave arc shape of the thread forward surface. The thread forward surface extends toward the rod body and connects with the concave arc shape of the thread reverse surface, and forms a large concave arc shape with the thread bottom. The entire shape is presented as a curved surface. The screw of the present invention is less likely to damage the plastic workpiece when it is screwed into the plastic workpiece, and can avoid generating a large internal stress, and increase the pull-out force of the screw.

Description

Screws for plastic materials

The present invention relates to screws, and in particular to a screw used in plastic materials.

Generally, when a screw is locked into a workpiece, it cuts the workpiece with its thread and then screws into the workpiece. In order to cut into the workpiece, the traditional thread is designed to be angular, such as right angles or sharp angles, or sharp blades. However, when such a traditional screw is locked into a workpiece made of plastic material, due to the special properties of plastic materials, the thread of the screw often damages the surface of the plastic workpiece where the screw contacts the screw. Especially when used on a plastic workpiece made of fiberglass, the fiberglass will be cut and affect the structure of the material. What's worse, when such a traditional screw is drilled into a plastic workpiece, it may cause internal stress in the plastic material, reducing the material performance.

The present invention provides a screw for use in plastic materials, comprising a head, a tip, a rod and a thread, wherein the thread surrounds the outer surface of the rod in a spiral protrusion, the ridge cross section of the thread is in an arc shape, the intersection of the thread and the rod is in a concave arc shape, the concave arc radius r1 of the thread forward surface is greater than the concave arc radius r2 of the thread reverse surface, and in an embodiment, the concave arc radius r1 of the thread forward surface is greater than the concave arc radius r2 of the thread reverse surface. The curvature of the concave arc shape of the reverse surface of the thread is less than that of the reverse surface of the thread. The concave arc shape of the reverse surface of the thread is connected to the circular arc shape of the thread ridge line, and the reverse surface of the thread and the rod body form an approximately perpendicular concave arc surface. The circular arc shape of the thread ridge line is connected to the concave arc shape of the thread forward surface. Between the two threads, the thread forward surface extends toward the rod body and connects to the concave arc shape of the reverse surface of the thread, and forms a large concave arc shape with the thread tooth bottom.

The thread and the rod between the threads of the present invention are all arc-shaped or concave arc-shaped curved surfaces, so it is less likely to damage the plastic workpiece when screwing into the plastic workpiece. Unlike the thread of a traditional screw, which has an angular shape and cuts or squeezes the plastic workpiece when contacting the plastic workpiece, causing damage, and the contact with the plastic workpiece is more difficult. The contact surface is relatively smooth, which can prevent the screw and the plastic workpiece from being damaged due to the generation of large internal stress. The concave curved surface on the reverse side of the thread, which is approximately perpendicular to the rod body, can increase the pull-out force of the screw, preventing the screw from slipping out of the plastic workpiece when subjected to external force, solving the problem of traditional screws mentioned in previous technologies.

100: Screws used for plastic materials

10: Rod body

20: Thread

21: Forward surface

22: Reverse side

24: Arc shape

26: Large concave arc shape

28: Inclined surface

27: Concave curved surface

30: Head

40: Tip

r1: Radius of the longitudinal surface

r2: Reverse surface radius

Figure 1 is a three-dimensional diagram of the screw used for plastic material of the present invention.

Figure 2 is a plan view of Figure 1.

Figure 3 is a longitudinal cross-sectional view of a portion of Figure 1.

Figure 4 is a partially enlarged schematic diagram of Figure 3.

Figure 5 is a partially enlarged schematic diagram of Figure 1.

In order to enable the examiner to have a further understanding of the characteristics and features of the present invention, the following preferred embodiments are listed and illustrated as follows: FIG1-FIG5 shows a screw 100 for use in plastic materials provided by the present invention, comprising a head 30, a tip 40, a rod 10 and a thread 20, the thread 20 being spirally protruding around the outer surface of the rod 10, and FIG3-FIG4 showing that the ridgeline section of the thread 20 is in the shape of an arc. 24, the direction of the thread 20 facing the screw tip 40 is defined as the forward surface 21, and the direction of the thread 20 facing the screw head 30 is defined as the reverse surface 22. The forward surface 21 and the reverse surface 22 of the thread 20 are concave arc-shaped at the intersection with the rod 10 (see r1 and r2). The concave arc-shaped radius r1 of the forward surface 21 of the thread 20 is greater than the concave arc-shaped radius r2 of the reverse surface of the thread 20. Alternatively, as can be seen from FIGS. 3-4, the forward surface 21 of the thread 20 is concave arc-shaped. The curvature of the concave arc shape of the thread 21 is smaller than the curvature of the concave arc shape of the reverse surface 22 of the thread 20, that is, the concave arc shape of the forward surface 21 extends toward the rod 10 in a manner with a smaller degree of bending, while the concave arc shape of the reverse surface 22 extends in the reverse direction of the rod 10 in a manner with a larger degree of bending. In the embodiment, when viewed from the screw head 30 in the direction of the screw, the reverse surface 22 of the thread 20 is approximately perpendicular to the rod 10, and the concave arc shape of the reverse surface 22 of the thread 20 is approximately perpendicular to the rod 10. There is a concave arc surface 27 approximately perpendicular to the rod body between the arc shape 24 of the thread ridge line, and the other side of the arc shape 24 of the thread ridge line is extended to connect with the concave arc shape of the forward surface 21 of the thread 20, and between the two threads 20, the forward surface 21 of the thread 20 extends toward the rod body 10 and connects with the concave arc shape of the reverse surface 22 of the thread 20, and forms a large concave arc shape 26 with the tooth bottom of the thread 20, and the shape of the screw of the present invention is formed by repeated connection. In addition, there is an inclined surface 28 between the concave arc shape of the forward surface 21 of the thread 20 and the arc shape 24 of the thread ridge line, and the inclined surface 28 is a curved surface. Therefore, the threads 20 in the screw of the present invention and the surface of the rod 10 between the threads 20 are both curved surfaces.

The above is an introduction to the components and features of a screw 100 for plastic materials provided by a preferred embodiment of the present invention. The use features of the screw are described as follows: When the screw of the present invention is locked into a plastic workpiece, the plastic workpiece is broken by the tip 40, and then the thread 20 is screwed into the plastic workpiece. The thread 20 of the present invention and the surface of the rod 10 between the threads 20 are either arc-shaped or concave arc-shaped curved surfaces. Therefore, during the operation, the contact surface between the rod 10 and the plastic workpiece is relatively smooth. Unlike traditional screws, which have angular threads and cut or squeeze the plastic workpiece when in contact with it, causing damage, more importantly, it can avoid generating internal stress like traditional screws, which damages both the screw and the plastic workpiece. The reverse surface 22 of the thread 20 of the present invention is a concave curved surface 27 that is approximately perpendicular to the rod 10. After the screw is locked into the plastic workpiece, the concave curved surface 27 can function as a barrier to prevent the screw from slipping out of the plastic workpiece when subjected to external force or vibration, thereby increasing the pull-out force of the screw.

The above disclosure is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes made by relevant technical personnel in the technical field based on the present invention should fall within the scope of the present invention.

100: Screws used for plastic materials

10: Rod body

20: Thread

21: Forward surface

22: Reverse side

24: Arc shape

26: Large concave arc shape

28: Inclined surface

27: Concave curved surface

30: Head

40: Tip

Claims (10)

A screw used for plastic material includes a rod and a thread, the thread surrounds the outer surface of the rod in a spiral protrusion, wherein the ridge section of the thread is in an arc shape, the intersection of the thread forward surface and the rod is in a concave arc shape, the intersection of the thread reverse surface and the rod is in a concave arc shape, and the radius of the concave arc shape of the thread forward surface is larger than the radius of the concave arc shape of the thread reverse surface. As described in item 1 of the patent application scope, the screw used for plastic material, the concave arc shape of the thread forward surface between two threads is connected with the concave arc shape of the reverse surface, so that the space between the two threads and the bottom of the thread form a large concave arc shape. As described in item 1 of the patent application scope, a screw used for plastic material, wherein the concave arc shape of the thread longitudinal surface is connected to the circular arc shape of the thread ridge line. A screw used for plastic material includes a rod and a thread, the thread is spirally protruding around the outer surface of the rod, wherein the ridge section of the thread is in an arc shape, the intersection of the thread forward surface and the rod is in a concave arc shape, the intersection of the thread reverse surface and the rod is in a concave arc shape, and there is an approximately vertical concave arc surface between the concave arc shape of the thread reverse surface and the arc shape of the thread ridge line. As described in item 4 of the patent application scope, the screw used for plastic material, wherein the concave arc shape of the thread forward surface between two threads is connected with the concave arc shape of the reverse surface, so that the space between the two threads and the root of the thread form a large concave arc shape. As described in item 4 of the patent application scope, a screw used for plastic material, wherein the concave arc shape of the thread longitudinal surface is connected to the circular arc shape of the thread ridge line. A screw used for plastic material includes a rod and a thread, the thread is spirally protruding around the outer surface of the rod, wherein the ridge section of the thread is in an arc shape, the intersection of the thread forward surface and the rod is in a concave arc shape, the intersection of the thread reverse surface and the rod is in a concave arc shape, and the curvature of the concave arc shape of the thread forward surface is smaller than the curvature of the concave arc shape of the thread reverse surface. As described in item 7 of the patent application scope, a screw used for plastic material, wherein a slope is formed between the concave arc shape of the thread longitudinal surface and the circular arc shape of the thread ridge line, and the slope is a concave arc curved surface. A screw for plastic material includes a rod and a thread, wherein the thread surrounds the outer surface of the rod in a spiral protrusion, wherein the ridge cross section of the thread is in an arc shape, the intersection of the thread forward surface and the rod is in a concave arc shape, the intersection of the thread reverse surface and the rod is in a concave arc shape, and the thread between the two threads is in a concave arc shape. The concave arc shape of the forward surface is connected with the concave arc shape of the reverse surface, so that the two threads and their tooth bottoms form a large concave arc shape. There is an approximately vertical concave arc surface between the concave arc shape of the reverse surface of the thread and the arc shape of the thread ridge line. There is an inclined surface between the concave arc shape of the forward surface of the thread and the arc shape of the thread ridge line, and the inclined surface is a concave arc surface. As described in item 9 of the patent application scope, the screw used for plastic material, wherein the curvature of the concave arc shape of the thread forward surface is smaller than the curvature of the concave arc shape of the thread reverse surface.

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