Patent Application
20090158569
The present invention relates to an installation tool used when a helical coil insert of diamond-shaped cross section is inserted into an internally threaded part, as well as to a correction tool used when the installed helical coil insert is corrected.
When a steel bolt is threadably inserted into an internally threaded part (female thread part) formed in a member made of aluminum or another such soft material, the internally threaded part sometimes deforms.
One corrective measure is to form an internally threaded part with a somewhat large diameter in the soft material, to insert a steel helical coil insert having a diamond-shaped cross section into the internally threaded part, and to form a new internally threaded part using this helical coil insert. Since the helical coil insert is made of steel, the new thread is more rigid and deformation is not a concern.
Helical coil inserts are formed by winding a steel wire having a diamond-shaped cross section, with one end of the winding bending towards the center. This bent portion is referred to as a tang. This tang is held with a tool and is inserted into the internally threaded part while the helical coil insert is rotated.
After insertion, the tang is an unnecessary hindrance. Since a notch is formed in the base of the tang, the tang can be broken off at the notch and removed by shaking the distal end of the tang.
A specialized tool disclosed in, e.g., Japanese Patent Laid-Open Publication No. 11-156751 (JP 11-156751 A) is needed to remove the tang. This specialized tool is described hereinbelow with reference to
As shown in
A helical coil insert 108 is inserted in advance into the member 101. A tang 109 provided at one end of the helical coil insert 108 is located deep within the hole. To bend the tang 109, the handle 105 is lowered to lower the shaft 104.
When brought into contact with the tang 109, the hook 107 rotates counterclockwise in the diagram around the pin 106, as shown in
Next, when the hook 107 falls below the tang 109, the hook rotates by its own weight clockwise in the diagram around the pin 106, as shown in
The tang 109 must be powerfully pulled up with the hook 107 in order to bend the tang 109. It is difficult to regulate this force. If the upward force is too great, a first coil 111 of the helical coil insert 108 separates from the internally threaded part 112 as shown by the broken lines in
In conventional practice, an inspection is conducted, and the helical coil insert 108 is replaced with a new insert if the first coil 111 has separated. The helical coil insert then becomes useless and replacement costs are incurred.
An installation tool for inserting the helical coil insert 108 into the internally threaded part 112 and a tang-breaking tool 100 for bending the tang are also required, and therefore the number of tools increases.
In view of this, there is a need for a multifunction tool whereby the helical coil insert can be used effectively and the number of tools can be reduced.
According to a first aspect of the present invention, there is provided a helical coil insert installation tool for use in installing a helical coil insert into an internally threaded part, the helical coil insert being formed by winding a wire of diamond cross section into a coil and having one end extending into a center of the coil to provide a tang, the helical coil insert installation tool comprising: a rod-shaped tool shaft; a tang pincer provided at one end of the tool shaft for pinching the tang when the helical coil insert is threadedly inserted into the internally threaded part or when the tang is folded over; a hook provided on the tool shaft for hooking onto a distal end positioned next to the tang of the helical coil insert; and a handle provided at an opposite end of the tool shaft for turning the tool shaft when the helical coil insert is threadedly inserted into the internally threaded part.
The tang is pinched by the tang pincer, and the tool shaft is turned with the handle, whereby the helical coil insert is threadably inserted into the internally threaded part. The tool shaft then moves in the axial direction while the tang is pinched by the tang pincer. The tang can thereby be removed from the helical coil insert. If a first winding of the helical coil insert separates from the internally threaded part, the first winding is hooked and returned to the internally threaded part by the hook.
Thus, according to the invention, a multifunction took is provided, wherein three different operations can be carried out with one tool.
If the first winding of the helical coil insert separates from the internally threaded part, the helical coil insert does not need to be replaced with a new insert because the first winding can be returned to the internally threaded part by the hook. Therefore, the helical coil insert can be used effectively.
Preferably, the tool shaft has a cylindrical weight disposed on the tool shaft and vertically slidable therealong to impart an impact to the shaft tool to thereby guide the distal end of the helical coil insert into the internally threaded part when the distal end is displaced from the internally threaded part.
When the first winding of the helical coil insert has separated from the internally threaded part, the first winding often rests on the crest of the internally threaded part. When the portion resting on the crest is subjected to an impact, this portion easily fits into the recession of the internally threaded part. Specifically, the helical coil insert can be easily corrected by creating a force of impact with the cylindrical weight.
In a preferred form, the hook comprises a groove formed by cutting out a part of the tool shaft. Since there is no need to prepare new material to form the groove, the cost of the helical coil insert installation tool can be reduced.
Desirably, the hook comprises a projection formed protruding in an axially perpendicular direction from the tool shaft. The projection can be seen through the entrance in the internally threaded part. The operation is simplified because the projection can easily hook onto the helical coil insert.
According to a second aspect of the present invention, there is provided a helical coil insert correction tool for returning a first winding of a helical coil insert to an internally threaded part when the first winding has separated from the internally threaded part, the helical coil insert correction tool comprising: a rod-shaped tool shaft; and hooks that are provided to the tool shaft and that hook onto one end of the helical coil insert.
The helical coil insert correction tool is a simple tool having merely a hook provided to a rod-shaped tool shaft. Since the structure is simple, the cost of the helical coil insert correction tool can be reduced.
Preferably, the tool shaft has a cylindrical weight disposed on the tool shaft and vertically slidable therealong to impart an impact to the shaft tool to thereby guide the distal end of the helical coil insert into the internally threaded part when the distal end is displaced from the internally threaded part.
When the first winding of the helical coil insert has separated from the internally threaded part, the first winding rests on the crest of the internally threaded part. When this portion is subjected to impact, this portion easily fits into the recession of the internally threaded part. Specifically, the helical coil insert can be easily corrected by creating a force of impact with the cylindrical weight.
In a preferred form, the hook comprises a projection formed protruding in an axially perpendicular direction from the axis of the tool shaft. The projection can be seen through the entrance of the internally threaded part. The operation is simplified because the projection easily hooks on the helical coil insert.
Desirably, the hooks are provided to both ends of the tool shaft, and one hook is larger than the other hook.
The member has two internally threaded parts, a small-diameter threaded part and a large-diameter threaded part; and a single helical coil insert correction tool can be used to make a correction in cases in which the distal end of the helical coil insert has separated from both internally threaded parts. Consequently, it is possible to create a helical coil insert correction tool having multiple functions.
In
The handle 15 is composed of an L-shaped handle shaft 16, a handle grip 18 that can be grasped by an operator, a nut 17a for fixing the handle grip 18 to the handle shaft 16, and a nut 17b for fixing one end of the handle shaft 16 to the tool shaft 11.
The hook 14 is, e.g., a groove 19 formed by cutting out a part of the tool shaft 11.
The following is a description of the action of the helical coil insert installation tool 10 having the configuration described above.
A helical coil insert 21 is a metal component wherein a coil having a diamond-shaped cross section is wound into a coil shape, and one end of the wire extends into the center of the coil to form a tang 22, as shown in
When the helical coil insert 21 is threadably inserted into the internally threaded part 23 as shown in
As a result, the tang 22 bends and separates from the helical coil insert 21 as shown in
The fact that the first winding 26 has separated from the internally threaded part 23 can be confirmed by viewing the internally threaded part 23 from above.
When it is determined that the first winding 26 has separated from the internally threaded part 23, the tool shaft 11 is turned as shown by the arrow (4). The tool shaft 11 is then raised as shown by the arrow (5), and the groove 19 is made to face the first winding 26.
The groove 19 then hooks onto the first winding 26, as shown in
As described above, the helical coil insert installation tool 10 can be used to carry out three steps, including a step for threadably inserting the helical coil insert 21 into the internally threaded part 23, a step for bending the tang 22, and a step for returning the first winding 26 to the internally threaded part 23.
The groove 19 for carrying out a correction step is a groove formed by cutting out a recession in the tool shaft 11 orthogonal to the axial direction. Since new material does not need to be prepared in order to form the groove 19, the cost of the helical coil insert installation tool 10 can be reduced.
In the example above, the hook 14 is composed of the groove 19, but the hook 14 can also be embodied in another form. Another embodiment is described in the following diagram.
The hook 14 may be a projection 28 such as is shown in
Next, a modification of the helical coil insert installation tool will be described in
A cylindrical weight 41 for subjecting the tool shaft 11 to impact in the pulling direction of the hook 14 is provided to a helical coil insert installation tool 40 to be capable of moving in the axial direction, as shown in
The groove 19 hooks onto the first winding 26 of the helical coil insert 21, as shown in
Specifically, the first winding 26 that has separated from the internally threaded part 23 often rests on the crest of the internally threaded part 23. When this portion resting on the crest is subjected to impact, this portion easily fits into the recession of the internally threaded part 23. Specifically, the helical coil insert 21 can be easily corrected by creating a force of impact with the cylindrical weight 41.
With the helical coil insert installation tools 10, 40 described above, one tool can be used to carry out three steps, including a step for threadably inserting the helical coil insert 21 into the internally threaded part 23, a step for bending the tang 22, and a step for returning the first winding 26 to the internally threaded part 23.
Although the threadable insertion step and the step for bending the tang are vital, the correction step is not always necessary. One possibility, which is thought to increase operating efficiency, is to perform the correction step as necessary separately from the threadable insertion step and the step for bending the tang.
To perform the steps separately, a specialized tool for the correction step is preferably prepared in addition to the helical coil insert installation tools 10, 40.
In view of this, the following is a description of a helical coil insert correction tool as this specialized tool for the correction step.
As shown in
The projection 53 then hooks onto a first winding 56 of a helical coil insert 54 in
The helical coil insert correction tool 50 is configured from the rod-shaped tool shaft 51 and the projection 53, and therefore has a simple structure. Therefore, the cost of the helical coil insert correction tool 50 can be reduced. If a projection 53 is used, the projection can be visually inspected with ease through the internally threaded part 55. Therefore, the projection 53 can easily hook onto the first winding 56.
The helical coil insert correction tool 50 may also be a helical coil insert correction tool 50B or 50C in the embodiments described below.
A cylindrical weight 57 for subjecting the tool shaft 51 to impact in the pulling direction of the hook 52 is provided to a helical coil insert correction tool 50B while allowed to move in the axial direction of the tool shaft 51, as shown in
When the cylindrical weight 57 collides with the stopper 58, the projection 53 subjects the helical coil insert to impact and returns the helical coil insert to the internally threaded part.
The helical coil insert correction tool 50C has a small hook 62 provided to one end of a tool shaft 61, and a large hook 63 provided to the other end of the tool shaft 61, as shown in
The workpiece has two internally threaded parts, a small-diameter threaded part and a large-diameter threaded part; and a single helical coil insert correction tool 50C can be used to make a correction in cases in which the distal end of the helical coil insert has separated from both internally threaded parts. Consequently, it is possible to create a helical coil insert correction tool having multiple functions.
Instead of a round bar, the tool shaft may be a square or hexagonal bar, and the cross-sectional shape thereof is arbitrary. Instead of a cylinder, the cylindrical weight may be a square or polygonal block, and the cross-sectional shape thereof is arbitrary.
The projection was described as being integrated on the tool shaft in the embodiments, but the projection may also be formed as a protrusion fixed in place on the tool shaft by welding or bolts. The protrusion is not limited to being integrated on the tool shaft or subsequently attached.
As described above, the present invention can be used as a tool in the operation of installing a helical coil insert in an internally threaded part.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-157763 | Jun 2006 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2007/060321 | 5/15/2007 | WO | 00 | 12/4/2008 |
