Tohnichi Mfg. Co., Ltd.

Shibaura Institute of Technology

Tomohiro Ogata

Seiji Ito

Kyoichi Komatsu

Hiroshi Tsuji

Shozo Aikawa

Yasuhiro Yamamoto

Yuji Kato

Tetsuya Yokoyama

Satoshi Takaku

Naoya Masuda

Koichi Shimura

Kyo Kan

Shinji Hashimura

Provided is a nut and a bolt tightening method for fastening an object, wherein a tightening force is applied on the object by rotating a nut or a bolt in a state in which a predetermined tension force is applied on the bolt in the axial direction of the bolt. When the tensile force exerted on the bolt decreases as the tightening force increases and after a timing when an inflection point occurs in a time course change in a ratio of an amount of change in the tensile force exerted on the bolt to an amount of change in an angle of rotation of the nut or the bolt, the tightening resulting from the rotation of the nut or bolt is terminated and the tensile force applied on the bolt is removed.

Nut and bolt tightening method and tightening device

Tightening device can fasten a fastening element by a target tightening force with good accuracy and facilitate automation. The tightening device includes a cylindrical drive socket holding a nut in the lower end opening thereof; a nut holder disposed inside the drive socket, a bolt passing through a bottom thereof, and regulating movement of the nut held by the drive socket toward the tip end of a threaded par; a tension rod which is disposed inside the nut holder and the lower end face of which has a threaded hole into which a portion of the threaded part that is further on the tip end side than the nut is screwed; a sensor for detecting tension force; a first motor for turning the tension rod around an axis that extends in the vertical direction; and a second motor for turning the drive socket around an axis.

Tightening device

A fastening device for fastening a bolt to a fastening target object, wherein the bolt has a bolt head female screw section in an inner circumferential surface of a recess provided in an upper surface of a bolt head section. The fastening device includes a tension rod having a rod male screw section engaging the bolt head female screw section; a drive socket circumferentially surrounding the tension rod and having a lower end section with a grasper for laterally grasping the bolt head section; a supporter circumferentially surrounding the drive socket and having a lower end section protruding downward beyond a lower end section of the drive socket; a sensor for sensing compression force acting on the supporter in the upward/downward direction; a first motor for rotating the tension rod around an axis extending in the upward/downward direction; and a second motor for rotating the drive socket around the axis.

Fastening device

In a fastening device for fastening a bolt, a male thread is formed on a side surface of a bolt head part, and a part to be engaged is formed on a top surface of the bolt head part. The fastening device includes a bit having a tension rod having a rod female thread part, and an engaging part installed inside the tension rod and engaging the engaged part, the bit causing the bolt to rotate where the engaged part and engaging part are engaged; a supporter surrounding the tension rod in the circumferential direction such that the lower end part thereof protrudes below the lower end part; a sensor for sensing vertical compression force acting on the supporter; a first motor for causing the bit to rotate about the axis; and a second motor for causing the tension rod to rotate about the vertically extending axis.

A tightening tool such as a torque wrench is provided in which electric power can be fed to an electronic circuit with eliminating the need for a battery and achieving daily maintenance-free. In the tightening tool, when a tightening torque has reached a set torque value and a torque limiter is actuated, an electronic circuit unit that has obtained a detection signal outputted from a torque limiter actuation detection unit outputs a tightening completion signal. The tightening tool has a power generation unit for feeding electric power to the electronic circuit unit at least during the actuation of the torque limiter. The power generation unit performs photovoltaic power generation, electromagnetic induction power generation, power generation by conversion from mechanical energy into electrical energy, or temperature difference power generation.

Tightening tool

A torque wrench equipped with a cam-type torque detection mechanism is provided which is capable of detecting a torque with high accuracy, providing a non-unusual-feeling of handle operation after torque has been detected, and enabling tightening of fastened members such as bolts with safety. In a torque wrench equipped with the cam-type torque detection mechanism, a cam portionformed on the outer circumference of a tubular camincludes: a static engagement cam surfacewith which a roller memberin a static status engages in a non-operated status; a gradually increasing torque peak cam surfacewhich is connected to the static engagement cam surfaceand with which the roller memberis brought into contact while moving to thereby gradually increase the torque peak value; a cam top surfaceforming the cam top portion continued to the gradually increasing torque peak cam surface; a gradually decreasing torque cam surfacefor gradually decreasing a plus torque to the roller memberto zero; and a minus torque cam surfacefor imparting a minus torque to the roller memberhaving passed over the gradually decreasing torque cam surface

Torque wrench

To make improvements in torque wrenches with a torque limiter that uses a cam mechanism and to provide a torque wrench that realizes more stable operation and is capable of highly precise tightening. In a torque wrench with a torque limiter that uses a cam mechanism, a solid columnar roller memberis engaged with a cam partof a cam shaftsuch that it is rotatably supported by a roller support lever membermounted in a head portionsuch as to be rotatable around a support shaftand such that it is pressed against the cam partby a spring force transmitting rodbiased by a torque setting spring. The roller support lever memberis configured such that the distance rfrom the support shaftto a point of application of force of the spring force transmitting rodis longer than the distance rfrom the support shaftto the roller member

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Tokyo, Japan

Tomohiro Ogata