JPS6020819Y2 - bolt - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bolt that is unlikely to suffer from poor tightening due to seizure.

Conventional ordinary bolts have effective threads with the same thread shape, root diameter, and effective diameter at the same pitch from the tip of the bolt shaft to the required location, so it is difficult to screw nuts such as detent nuts. When tightening the nut, it may not bite properly, and while the nut is rotated until the required tightening force is obtained, the material of the bolt may have poor thermal conductivity, or there may be scratches or paint on the effective thread. There is a problem of seizing and poor tightening, especially when nuts such as detent nuts are screwed to the tightening position close to the bolt head, such as bolts used for tightening pads for fixing automobile tanks. For bolts that require sufficient clearance between the tip of the bolt shaft and the threaded nut, it is possible to tighten the bolt to a position quite far away from the tip of the bolt shaft without seizing the nut. The development of such a bolt is strongly desired in the industry, as it needs to be easy to thread and have good bite.

The present invention was completed with the aim of producing a bolt that met the above-mentioned demands, and as shown in the illustrated embodiment, an effective threaded portion provided on the front portion of the bolt shaft portion 1 is used. No. 2 is characterized in that a guide screw portion 3 having the same thread shape and pitch and slightly smaller outer diameter, root diameter, and effective diameter is provided following the effective screw portion 2.

When a bolt configured in this way is used in the same way as a conventional bolt to screw into a bolt having a female threaded part that matches the effective threaded part 2, the front part of the bolt shaft part 1 is Since it is formed in the guide thread part 3, which has the same thread shape and pitch as the effective thread part 2 provided in the guide thread part 3 and has a slightly smaller outer diameter, root diameter, and effective diameter, it has good bite. By lightly rotating the screwdriver, it can easily advance toward the effective threaded portion 2 under the guidance of the guide threaded portion 3, and there is no risk of seizing during this time.

Moreover, this guide thread part 3 is provided at the front end of the bolt shaft part 1 following the effective thread part 2, with the thread shape and pitch being the same, and the outer diameter, root diameter, and effective diameter being slightly smaller. By continuing to rotate further, the bolt moves smoothly to the effective threaded part 2, and the normal threading to the effective threaded part 2 is performed, and it is tightened at a position that leaves a sufficient margin from the tip of the bolt shaft part 1. Since the screwing distance of the bolt to the effective threaded part 2 can be kept to the minimum necessary, seizure will not occur regardless of the material of the bolt, scratches, or adhesion of paint, and there will be no seizure failure due to seizure. There is no risk of

Furthermore, even if the Naratoi loosens and becomes unscrewed from the effective threaded portion 2, the Naratoi will remain threaded onto the guide screw portion 3 of a considerable length, thereby accurately preventing the Naratoi from falling off. There are some advantages to doing so.

Note that the diameter of the guide screw portion 3 needs to be made smaller as the tightening torque increases, but it is optimal to make the diameter of the effective screw portion 2 about as small as the diameter of the effective screw portion 2.

Therefore, the present invention has great practical value as a bolt that eliminates the drawbacks of conventional bolts.

[Brief explanation of the drawing]

The drawing is a partially cutaway front view showing an embodiment of the present invention in use. 1: Bolt shaft part, 2: Effective thread part, 3: Guide thread part.

Claims (1)

[Scope of utility model registration request] The effective thread part 2 provided in the front part of the bolt shaft part 1 is a guide thread part 3 which has the same thread shape and pitch and has a slightly smaller outer diameter, root diameter, and effective diameter. Holt characterized by being provided following part 2.