MXPA99008370A - Threaded insert that has a removed tongue - Google Patents

Abstract

The present invention relates to a threaded insert, comprising a helical body of a cable having a helical shape, the helical body having a front end portion and a rear end portion, and a removable tongue connected to a first end of the wire in the front end portion of the helical body, characterized in that the rear end portion has a pair of adjustment slots formed on opposite sides on an internal surface of the final portion of the rear portion.

Description

THREADED INSERT WITH A REMOVABLE TONGUE Background of the Invention Field of the Invention The present invention relates to a thread insert having a removable tongue, which is screwed into a hole formed in a work to provide a female thread on the inner surface of the hole.

Description of the Related Art Thread inserts are helical parts used to form a female thread on the inner surface of an orifice formed in a work, which is made of a material having a relatively low hardness, such as plastics or aluminum. Figures 20-22 illustrate an example of conventional thread inserts. The thread insert is formed by winding a metal wire in helical form, and a male screw 31 and a female screw 32, respectively, are formed on the outer and inner surfaces of the helical wire. At the front end of the helical wire, a first coil portion 33 having a smaller diameter is formed, so that the thread insert can be screwed uniformly into a hole from the side of the first portion of the coil 33.

A removable tab 34 is formed at the front end of the first portion of the turn 33 to extend towards the center of a first portion of the turn 33, and a groove 35 is formed on the wire by cutting between the first portion of the turn 33. and the tongue 34 to facilitate the removal of the tongue 34. When the thread insert is used, the removable tongue 34 is held by a tool (not shown) inserted through the thread insert, and the thread insert is screwed into the tongue. a hole of a work by the tool. Next, the removable tab 34 is pushed by another tool inserted through the screwed insert, and the tab 34 is removed by breaking the wire in the slot 35. After the assembly of the tab 34, it is possible to screw a screw into the insert further. beyond the length of the insert. To remove the screwed insert at work, as shown in Figure 23, a stripping tool 37 is pushed towards the rear end portion 36 of the thread insert, so that a pair of cutting edges 35 of the tool 37 bite the internal thread 32 of the insert. Next, tool 37 is rotated to unscrew the work insert. However, the above thread insert has the following disadvantages. That is to say, that the previous thread insert can not be extracted unless a special disassembly tool 37 having sharp edges is used. Further, if the pushing force of the stripping tool 37 is too weak, the tool 37 does not form slots 38 having a sufficient depth, and it is not possible to rotate the thread insert by the tool 37. In contrast, if the The pushing force of the stripping tool 37 is too strong, the tool 37 elongates the diameter of the threaded insert, and there is a risk that the inner surface of the hole will be damaged. If the inner surface of the hole is damaged, it would be necessary to screw the hole to mount a new thread insert in the same hole, and the new thread insert should be larger than the original if the internal diameter of the hole was lengthened by the rerroscado . Therefore, the operation of the disassembly tool 37 is not easy and requires the skill of an expert. Additionally, because the slot 35 is formed on the front surface of the wire as shown in Figure 21, when the tongue 34 is pushed by the tool inserted through the thread insert, a fracture of the back surface 35a is generated. opposite the slot 35. However, the rear surface 35a is uniform, the stress generated by the push of the tongue 34 is not concentrated on a single point in the wire, and the breaking of the wire requires a large load.

Further, because the trailing end 36 of the insert is flat, when the thread insert is unscrewed, the edge 36a of the trailing end 36 scrapes the inner surface of the hole. Scraping along the trailing edge 36a not only increases the rotational resistance of the insert, but also increases the risk that the internal surface of the hole will be damaged.

Brief Description of the Invention An object of the present invention is to provide a thread insert, which can be easily removed without a special tool and the skill of an expert. To achieve the above object, the thread insert comprises a helical body having a front end portion and a rear end portion, and a removable tab connected to the front end portion of the helical body, where at least one engagement slot is formed in the posterior end portion of the helical body. In the thread insert of the present invention, by inserting a general tool, such as an extraction tool (flat head screwdriver) into the coupling slot, it is possible to rotate the screw insert firmly screwed into the work, and it is possible to Easily remove the threaded insert without the skill of an expert.

The rear end portion may have a pair of mating slots formed at a 180 ° interval on the inner surface of the rear end portion. The helical body may comprise a female thread formed on an inner surface of the helical body, and a male thread formed on the outer surface of the helical body. In addition, the removable tab can have a circular portion having an external diameter, which is smaller than that of the helical body. Another object of the present invention is to facilitate the disassembly of the removable tab after the insert is screwed into a job. To achieve this object, at least one cutting groove can be formed between the front end portion of the helical body and the removable tongue on at least one of a surface facing the rear end portion and a surface facing a central axis of the helical body. In this case, when the removable tab is pushed forward, the stress will be concentrated on the bottom of the cutting slot, and a fracture will be generated from the bottom of the cutting slot. Therefore, it is possible to facilitate the cutting of the detachable slot. The cutting groove may have a "V" shaped cross section, and may be formed between the front end portion of the helical body and the circular portion of the removable tongue. The rear end portion may have a beveled rear end face on an outer side of the helical body. In this case, because the rear end portion does not scrape the inner surface of the insert when the thread insert is unscrewed, it is possible to prevent damage to the inner surface of the hole in which the thread insert was screwed. The rear end surface of the rear end portion may additionally have a planar face perpendicular to an external surface of the helical body, and the entire circumferential edge of the planar face may be bevelled. In addition, the coupling groove may have a tool contact surface, which intersects the internal surface of the helical body at a substantially right angle or an acute angle, and which is also oriented towards the direction of rotation of the hands. of the clock. In this case, the rotational force applied to a screwdriver tool can be effectively transmitted to the coupling slots.

Brief Description of the Drawings Figure 1 is a rear view of a thread insert according to the first embodiment of the present invention. Figure 2 is a side view of the thread insert according to the first embodiment. Figure 3 is a front view of the thread insert according to the first embodiment. Figure 4 is a cross section in the plane B-B • in Figure 3. Figure 5 is an enlarged view of the rear end of a wire forming the thread insert of the first embodiment. Figure 6 is a rear view of a thread insert of the first embodiment when unscrewed. Figures 7 and 8 are, respectively, a front view and a side view of a thread insert according to the second embodiment of the present invention. Figure 9 is a cross section of the C-C plane in Figure 7. Figure 10 is a view illustrating a method for forming the coupling slots in the third embodiment of the present invention. Figure 11 is a view illustrating the method for forming the coupling slots in the fourth embodiment of the present invention.

Figure 12 is a view illustrating a method for forming the coupling slots in the first embodiment of the present invention. Figures 13-17 are cross sections illustrating modifications of the cutting groove. Figures 18 and 19 are rear views illustrating modifications of the beveling of the end of the wire. Figure 20 is a rear view of an example of a conventional thread insert. Figure 21 is a side view of the conventional thread insert. Figure 22 is a front view of the conventional thread insert. Figure 23 is a rear view of the conventional thread insert when unscrewed.

Detailed Description of the Invention Figures 1-6 illustrate a thread insert having a removable tab according to the first embodiment of the present invention. This thread insert comprises a helical body having a front end portion 3 and a rear end portion 6, and a removable tongue 4 connected to the front end portion 3 of the helical body. The removable tongue 4 is used to apply a rotational force to the thread insert when the thread insert is screwed into a job. A female thread 2 is formed on the inner surface of the helical body, and a male thread 1 is formed on the outer surface of the helical body. In this embodiment, the helical insert is manufactured by forming a spiral-shaped metal wire, and the metal wire has a rhomboidal cross-section. The wire is made of a metal that has a hardness greater than that of the work for which the thread insert is used. A pair of coupling slots 10 are formed on the inner surface of the rear end portion 6 of the helical body at a 180 ° interval. As shown in Figure 1, each of the coupling slots 10 has a concave surface 10a intersecting the inner surface of the helical body at an obtuse angle, and a tool contact surface 10b, which is substantially perpendicular. to the internal surface of the helical body. The tool contact surface 10b may be formed to intersect the internal surface of the helical body at an acute angle. The contact surfaces 10b are oriented in the direction of clockwise movement when the thread insert is viewed from behind, and the contact surfaces 10b engage with both side ends of a tool 13 (eg, a tool extraction), as shown in Figure 6, when the tool 13 unscrews the thread insert. As shown in Figure 3, the removable tab 4 consists of a semicircular portion 3a having an outer diameter, which is smaller than that of the helical body, and a straight portion 4a extending from the front end of the portion circular 3a towards the central axis of the helical body. Between the circular portion 3a and the front end portion 3 of the helical body, a cutting groove 11 is formed to separate the detachable tab 4 on a rearward facing surface. In other words, the cutting groove 11 is positioned at the point of modification of the radius of curvature of the wire, and the cutting groove 11 is oriented rearwardly. As shown in Figures 3 and 4, the cutting groove 11 is a groove with a "V" shaped cross section having first and second surfaces Ia and 11b, and a transverse line 11c formed between the first and second surfaces. 11 and 11b, so that it extends substantially perpendicular to the internal surface of the helical body. The thread insert 11 and the coupling groove can be formed simultaneously by stamping or die cutting a straight metal wire before forming the metal wire into a spiral shape. In this case, the productivity for manufacturing thread inserts can be improved, and it is not necessary to use machining oil, which can be harmful to the atmosphere. However, the cutting groove 11 and the coupling groove 10 can be formed by machining or grinding after or before forming the metal wire in a spiral shape. Figure 5 illustrates the trailing end of the wire that forms the insert. As shown in Figures 5 and 1, a central planar surface 20 and beveled surfaces 15, 16, 17 and 18 are formed surrounding the flat surface 20 on the trailing end of the wire. The beveled surface 15-18 prevents the rear end portion 6 from scraping the inside surface of a work hole when the thread insert is unscrewed, thus, it is possible to decrease the rotational resistance of the insert and the risk that the inner surface of the hole is damaged. The flat surface 20 is perpendicular to a longitudinal direction of the wire, and the flat surface 20 avoids forming a sharp point in the center of the trailing end of the wire. The beveled surfaces 15-18 and the flat surface 20 can be formed by the aforementioned marking or die cutting at the same time as the formation of the grooves 10 and 11. However, those surfaces 15-20 can be formed by machining or rectification after or before forming the metal wire in a spiral form. In this embodiment, although the front end of the detachable tab 4 also has a beveled shape similar to that of the rear end of the rear end portion 6, the front end of the removable tab 4 may have another shape. To mount the thread insert in a pink hole of a job (not shown), a tool (not shown) is inserted through the thread insert from the rear end portion 6, and the removable tab 4 is held by the tool. Then, the thread insert is screwed, by turning the tool, towards the work hole by means of a self-tapping screw. When the insert is screwed to a predetermined depth, the tool is pulled from the screwed insert. Next, a second tool, such as a bolt through the thread insert, is inserted, and the removable tongue 4 is slit by the second tool to break the tongue 4 at the point of the cutting groove 11. When the tongue removable 4 is pushed by the second tool, because the cutting groove 11 is formed to face the rear end portion 6, the pushing force affects the cutting groove 11, so that the groove 11 widens, and can a fracture is easily generated from the transverse line 11c at the bottom of the groove 11. Therefore, the disassembly of the tongue 14 can be facilitated.

After removal of the tab 4, the tab 4 is removed, and a calibration inspection is performed to determine if the front end portion 3 was deformed to prevent the screws from being screwed. If there is no deformation of the thread insert, the insert assembly operation ends. Then, to remove the thread insert from the work, as shown in Figure 6, a third tool 13 is inserted along both coupling slots 10. This third tool can be, for example, an extraction tool that it has a tip width, which is greater than the internal diameter of the thread insert and smaller than the maximum distance between both coupling slots 10. Then, the third tool 13 is rotated in the counter-clockwise direction clock while coupling the tool 13 with the contact surfaces 10b of the coupling slots 10, and the thread insert is unscrewed and removed from the work hole. According to the thread insert of the present embodiment, because the coupling slots 10 are preformed in the rear end portion 6, it is possible to safely rotate the screwed insert using an ordinary tool, such as an extraction tool. , and the unscrewing of the insert can therefore be facilitated. Furthermore, it is not necessary to make the edges of the tool bite the inner surface of the insert, and there is no risk of the inner surface of the hole being damaged by the elongation of the insert. Additionally, because the cutting groove 11 is formed to be oriented rearwardly, when the removable tab is pushed forward, the stress will be concentrated at the bottom of the cutting groove 11, and a fracture will be generated from the bottom of the groove 11. cutting groove 11. Further, because the cutting groove 11 has a "V" shaped cross section, the fracture is easily generated from the transverse line 11c at the bottom of the V-shaped groove. , it is possible to facilitate the cutting of the detachable tongue 4. In the present embodiment, since the cutting of the detachable tongue 4 can be easily effected in comparison with the case of the conventional insert, the circular portion 3a of the tongue 4 can be lengthened without degrading the ease of cutting the tongue 4. Therefore, the outer diameter of the front end of the circular portion 3a can be decreased, and it is possible to improve the uniformity of the insertion of the Thread in the work hole. This effect is important, especially in the case where the diameter of the thread insert is large.

In addition, because the back end of the wire forming the insert is bevelled when surfaces 15-18 are beveled, when the thread insert is unscrewed by a tool, the rear end of the wire does not scrape the inner surface of a threaded hole. of a job. Therefore, it is possible to decrease both the rotational resistance of the thread insert and the risk that the inner surface of the hole will be damaged. Although four beveled surfaces 15-18 are formed in this embodiment, it may also be possible to form only one bevelled surface on the outer side of the helical body. Additionally, because the flat surface 20 formed on the trailing end of the wire to prevent a sharp point from being generated, the risk that the trailing end of the wire will wound or puncture the skin or clothing of the operator can be prevented. Further, in the present embodiment, because each coupling groove 10 has a concave surface 10a intersecting the internal surface of the helical body at an obtuse angle and a tool contact surface 10b intersecting the inner surface of the helical body at an acute angle or right angle, an operator can easily notice if a tool rotates in the direction of the screw insertion of the thread insert. Therefore, it is possible to prevent the internal surface of the threaded hole from being damaged by excessive screwing of the thread insert. Furthermore, in the case where the tool contact surface 10b intersects at an acute angle with the internal surface of the helical body, inserting the second tool in the rear end portion 6, and rotating the tool in the opposite direction to the hands of the watch, both side edges of the tool are firmly coupled with the acute angle of the coupling slot 10, and the rotational force is effectively transmitted to the thread insert. Figures 7-9 illustrate a second embodiment of the present invention, and this second embodiment is characterized in that a cutting groove 11 is formed on the internal surface (i.e., on the female thread 2) of the helical body. The cutting groove 11 has a "V" shaped cross section, and the depth thereof is about half the thickness of the helical body. However, the depth of the cutting groove is not limited in the present invention, and can be modified as the case may be. In this embodiment, when the detachable tab 4 is pushed forward by the second tool, the stress is concentrated on the point lie in which the transverse line 11c intersects the back surface of the wire, and a fracture will easily be generated from the point lie. . Therefore, the tongue 4 can be easily separated with a reduced thrust force. Figures 10-12, respectively, illustrate the modifications of the coupling grooves 10. In the embodiment illustrated in Figure 10, a pair of grooves 10 are formed having a square cross section in a straight wire, as shown in FIG. Figure 10 (a), and the wire is bent into a helical shape, as shown in Figure 10 (b), so that the slots 10 remain on the inner surface of the helical body at a 180 ° interval. In this case, because each coupling groove 10 has a pair of surfaces, which are substantially perpendicular to the internal surface of the helical body, it is easy to rotate the thread insert, using a tool, such as an extraction tool, towards both of the unscrewing direction and the screwing direction In the embodiment shown in Figure 11, a pair of grooves 10 are formed having an arched cross-section and a straight wire, as is shown in Figure 11 (a), and the wire bent into a helical shape, as shown in Figure 11 (b), so that the slot 10 has a semicircular cross section that remains on the inner surface of the helical body .

Further, in the embodiment shown in Figure 12, a pair of slots 10 having a trapezoidal cross-section in a straight wire are formed, as shown in Figure 12 (a), and the wire is bent into a helical shape in a shape as shown in Figure 12 (b), so that the slot 10 remains on the inner surface of the helical body. One side face of the coupling groove 10, intersects the inner surface of the helical body at an acute angle, and the other side face intersects the internal surface of the helical body at an obtuse angle. In this case, it is possible to obtain the same effects as those of the first modality. Furthermore, because the coupling groove 10 has a lower face, which is parallel to the longitudinal direction of the wire, the width of the opening of the coupling groove 10 is greater, therefore, the insertion of the second tool It can be facilitated. The shape of the coupling groove is not limited to those shapes, but can be modified to any shape if only the coupling groove can be coupled with an ordinary tool, such as an extraction tool. Also, the number of coupling slots 10 can be one or three, or more. For example, it is preferred to provide four coupling slots at a 90 ° interval, because, in this case, one of two positions of insertion of the tool can be selected according to what is preferred. Figures 13-17, respectively, illustrate the modifications of the cutting groove 11. As shown in Figure 13, the cutting groove 11 can be formed more deeply than that of the first embodiment. Also, as shown in Figures 14-17, the direction toward which the cutting tool 11 is oriented may be changed if necessary. In addition, the beveling of the rear end of the wire can be modified as long as the scraping of the inner face of the work hole is prevented. For example, only the outer edge of the final face can be beveled, as shown on face 18, or both outer and inner edges of the final face can be beveled, as shown in Figure 19. Although several modalities were explained of the present invention, the present invention is not limited to those embodiments, but it is also possible to combine selected features of each modality with each other.

Claims (10)

1. CHAPTER CLAIMEDICATORÍO Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following CLAIMS: 1.
2. A threaded insert having a removable tongue, characterized in that it comprises a helical body having a front end portion and a rear end portion, and a removable tongue connected to the front end portion of the helical body, where at least one tongue groove is formed. coupling in the posterior end portion of the helical body.
3. The thread insert according to claim 1, characterized in that a female thread is formed on an internal helical body surface, a male thread is formed on an external surface of the helical body, and the removable tongue has a circular portion that It has an external diameter, which is smaller than that of the helical body. 3.' The thread insert according to claim 1, characterized in that at least one cutting groove is formed between the front end portion and the removable tongue on at least one of a surface facing the rear end portion, and a surface facing a central axis of the helical body.
4. The threaded insert according to claim 1, characterized in that the rear end portion has a beveled rear end face on an external side of the helical body.
5. The thread insert according to claim 4, characterized in that the rear end surface of the rear end portion additionally has a flat face perpendicular to an external surface of the helical body.
6. 6. The thread insert according to claim 3, characterized in that the cutting groove has a "V" shaped cross section.
7. The thread insert according to claim 2, characterized in that the cutting groove is formed between the end portion of the helical body and the circular portion of the removable tongue.
8. The thread insert according to claim 1, characterized in that the rear end portion has a pair of coupling grooves formed at a 180 ° interval on the inner surface of the rear end portion.
9. 9. The thread insert according to claim 1, characterized in that the coupling groove has a tool contact surface, which is substantially perpendicular to the inner surface of the helical body and oriented towards the clockwise rotation direction, when seen from the back. The thread insert according to claim 1, characterized in that the coupling groove has a tool contact surface, which intersects the internal surface of the helical body at an acute angle and is oriented towards the direction of rotation of the hands of the clock, when seen from the back.