Insert nut structure, nut and shell assembly and method for assembling nut and shell assembly

A nut and shell assembly includes a shell and an inset nut structure. The shell has an inner surface that defines an inner shell space and a through hole to communicate the inner shell space with the outside. The insert nut structure includes an insert nut fixed in the through hole, and an elastic seal sleeved on the insert nut and in substantially tight contact with the shell in the through hole. The insert nut includes a columnar body fixed in the through hole, and a flange connected to one end of the columnar body. The flange has an outer diameter greater than that of the columnar body, and abuts against the inner surface of the shell.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwanese Application No. 100127580, filed on Aug. 3, 2011, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a nut structure, more particularly an insert nut structure, a nut and shell assembly and a method for assembling the nut and shell assembly.

2. Description of the Related Art

Conventionally, an insert nut is usually fixed into a blind hole of a plastic unit by heating and pressuring. A bolt can then be screwed to a screw hole in the insert nut for fixing an object. Since the insert nut is only fixed to the plastic unit by heating and pressuring, the insert nut has an insufficient resistance force against screw pull-out when a bolt is screwed to the insert nut.

Further, the applications of the nut differ depending on actual requirement. As such, how to conceptualize a structural design that can permit airtight and waterproof effects between a nut and a plastic unit when the nut is heated and fixed in a hole of the plastic unit becomes the subject of improvement of the present invention.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide an insert nut structure that can be be fixed conveniently to a shell and to increase a resistance force against screw pull-out, and to achieve a good waterproof effect.

According to one aspect of this invention, an insert nut structure includes an insert nut and an elastic seal sleeved on the insert nut. The insert nut includes a columnar body, and a flange connected to one end of the columnar body and having an outer diameter greater than that of the columnar body.

Preferably, the columnar body has an outer surface formed with a groove. The elastic seal is received engagingly in the groove.

Preferably, the elastic seal is sleeved on the columnar body and abuts against the flange.

Preferably, the columnar body has an outer surface formed with a groove proximate to a junction of the flange and the columnar body. The elastic seal is received engagingly in the groove.

Preferably, the elastic seal is made of one of natural rubber and synthetic rubber.

Preferably, the columnar body and the flange are integrally formed.

Another object of the present invention is to provide a nut and shell assembly that includes a shell and an insert nut structure. The insert nut structure can be be fixed conveniently to the shell to increase a resistance force against screw pull-out and to achieve a good waterproof effect.

According to another aspect of this invention, a nut and shell assembly includes a shell and an insert nut structure. The shell has an inner surface that defines an inner shell space, and a through hole to communicate the inner shell space with the outside. The insert nut structure includes an insert nut to be fixed in the through hole, and an elastic seal sleeved on the insert nut and in substantially tight contact with the shell in the through hole. The insert nut includes a columnar body fixed in the through hole, and a flange connected to one end of the columnar body. The flange has an outer diameter greater than that of the columnar body, and abuts against the inner surface of the shell. The insert nut has a T-shaped cross section. A thermal welding method for assembling the insert nut to the shell is accomplished by hot-melting from an interior to an exterior of the shell, which is different from the conventional hot coupling methods. Hence, the flange of the insert nut will abut against the inner surface of the shell. When a bolt is screwed to the insert nut from the exterior of the shell, a strong resistance force against screw pull-out can be provided. This makes it different from the conventional insert nuts.

Preferably, the shell further has a hole-defining wall that defines the through hole. The elastic seal is in substantially tight contact with the hole-defining wall when the insert nut is fixed in the through hole.

Preferably, the insert nut has an outer surface formed with a groove. The elastic seal is received engagingly in the groove.

Preferably, the elastic seal is sleeved on the columnar body and is in substantially tight contact with and is disposed between the flange of the insert nut and the inner surface of the shell.

Preferably, the insert nut has an outer surface formed with a groove proximate to a junction of the flange and the columnar body. The elastic seal is received engagingly in the groove.

Preferably, the elastic seal is made of one of natural rubber and synthetic rubber.

Preferably, the columnar body and the flange are integrally formed.

Yet another object of the present invention is to provide a method for assembling an insert nut and a shell. The insert nut can be fixed conveniently to the shell to increase a resistance force against screw pull-out and to achieve waterproof effect.

According to yet another aspect of this invention, a method for assembling an insert nut and a shell, where the shell has an inner surface and a through hole, and where the insert nut includes a flange, includes the steps of sleeving an elastic seal on the insert nut and fixing the insert nut to and in the through hole by thermal welding such that the elastic seal is in substantially tight contact with a hole-defining wall of the shell that defines the through hole, and such that the flange is in substantially tight contact with the inner surface of the shell.

The effect of the present invention resides in that because the flange of the nut abuts against the inner surface of the shell, a strong resistance force against screw pull-out can be provided. Further, because the elastic seal of the insert nut structure is in tight contact with the shell to achieve an airtight requirement, external water can be prevented from entering the shell.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1 to 4, a nut and shell assembly100according to the embodiment of the nut and shell assembly of the present invention comprises a shell1and an insert nut structure2.

With reference toFIG. 3, the shell1has an inner surface11that defines an inner shell space13, an outer surface15, and a through hole14that penetrates the inner and outer surfaces11,15such that the inner shell space13is connected spacedly to outside. The insert nut structure2includes an insert nut21insertedly fixed in the through hole14, and an elastic seal22sleeved on an outer surface of the insert nut21and in substantially tight contact with the shell1in the through hole14. Through this configuration, the waterproof effect between the insert nut structure2and the shell1can be achieved, so that external water can be prevented from entering the inner shell space13via the through hole14.

In this embodiment, the shell1is made of a plastic material. The shell1further has a hole-defining wall12defining the through hole14. The through hole14is circular.

The elastic seal22of the insert nut structure2is made of an elastic material. Because the elastic seal22can contact tightly with the hole-defining wall12, a good airtight effect between the elastic seal22and the hole-defining wall12can be achieved.

With reference toFIG. 4, the insert nut21includes a columnar body211, and a flange212connected to one end of the columnar body211and abutting against the inner surface11of the shell1when the columnar body211is fixed in the through hole14. An outer diameter of the columnar body211is slightly greater than that of the through hole14. An outer diameter of the flange212is greater than that of the columnar body211. The columnar body211and the flange212cooperatively define a screw-threaded hole213for receiving threadedly a bolt (not shown). The columnar body211has an outer surface formed with a first groove214that extends inwardly from the center thereof to receive engagingly the elastic seal22. Through this configuration, the elastic seal22can be stably and fixedly sleeved on the columnar body211and cannot be easily disengaged therefrom.

Alternatively, the outer surface of the columnar body211may be further formed with a second groove215that is spaced apart from the first groove214and that is proximate to a junction of the flange212and the columnar body211.

The elastic seal22is made of natural rubber, which has high elasticity and which can endure temperatures up to 250° C. The elastic seal22may also be made of silicone having similar properties as the natural rubber.

A method for assembling the insert nut21and the shell1according to the embodiment of the present invention is described below with reference toFIGS. 5,6,7and8.FIG. 5is a flow diagram of the method. The method includes steps91and92.

In step91, the elastic seal22is sleeved on the outer surface of the insert nut2. In this embodiment, the elastic seal22is sleeved on the columnar body211of the insert nut21such that the elastic seal22is engagingly received in the first groove214.

In step92, the insert nut21and the elastic seal22are fixed in the through hole14of the shell1by thermal welding.

As shown inFIG. 6, the insert nut structure2is first positioned in the through hole14of the shell1. At this time, the columnar body211abuts the inner surface11of the shell1, and a bottom end of the columnar body211extends into the through hole14.

With reference toFIGS. 7 and 8, alternatively, the flange212of the insert nut21is heated, for example, from 100° C. to 110° C., and is simultaneously pressed in the direction of an arrow (I). During heating and pressing of the insert nut21, the heat causes certain parts of the shell1to melt so that the columnar body211of the insert nut21can smoothly extend into the through hole14, and the elastic seal22can be compressed by the hole-defining wall12to extend into the through hole14. When the flange212abuts against the inner surface11(seeFIG. 8) of the shell1, the insert nut21cannot be moved further. After the melted material has solidified, the elastic seal22is positioned in a substantially tight contact with the hole-defining wall12. Thus, good airtight and waterproof effects can be achieved between the elastic sea22and the hole-defining wall12.

After the assembly is completed, because the flange212abuts against the inner surface11of the shell1, the insert nut21has a strong resistance force against screw pull-out, so that when a bolt is screwed to the insert nut21, the insert nut21cannot be easily displaced.

FIG. 9illustrates an alternative form of the insert nut structure2. In this embodiment, the elastic seal22is sleeved on the columnar body211and is in substantially tight contact with and is disposed between the flange212of the insert nut21and the inner surface11of the shell11. As such, a junction of the inner surface11and the elastic seal22is airtight, thereby preventing external water from entering the inner shell space13via the through hole14. Furthermore, the outer surface of the columnar body211is further formed with a second groove215(seeFIG. 4) proximate to a junction of the flange212and the columnar body211to receive engagingly the elastic seal22. Through this configuration, the elastic seal22can be stably and fixedly sleeved on the columnar body211and cannot be easily disengaged therefrom.

Referring toFIGS. 10 and 11, in combination withFIG. 5, in step91, the elastic seal22is sleeved on the columnar body211of the insert nut21until the elastic seal22is received engagingly in the second groove215, and in step92, the flange22of the insert nut21is heated and is pressed in the direction of the arrow (I) until the elastic seal22abuts against the inner surface11of the shell1(seeFIG. 11). The insert nut21cannot be further moved at this time. After the melted material solidified, the elastic seal22is positioned in a substantially tight contact with the inner surface11. Thus, good airtight and waterproof effects can be achieved in the junction of the elastic seal22and the inner surface11.

In summary, by sleeving the elastic seal22on the insert nut21of the insert nut structure2and by using a thermal welding method to fix the insert nut21in the through hole14of the shell1, the insert nut21can be conveniently assembled on the shell1, so that a good waterproof effect between the shell1and the insert nut21can be achieved. This results in reducing the assembling time and increasing the resistance force against screw pull-out. Hence, the objects of the present invention can be realized.