scholarly journals Experimental study on the factors affecting torque of beam-type implant torque wrenches

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hiroki Shiba ◽  
Yuji Sato ◽  
Junichi Furuya ◽  
Tokiko Osawa ◽  
Akio Isobe ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Leading Edge ◽  
Beam Width ◽  
Factors Affecting ◽  
Tightening Force ◽  
Torque Wrench ◽  
Screw Breakage ◽  
Beam Type ◽  
Accuracy And Repeatability ◽  
Excellent Accuracy

Abstract Background Screw breakage and loosening are the most common mechanical complications associated with implant treatment, and they may occur due to excess or inadequate screw tightening torque. When fastening and fixing the implant superstructure, screws are tightened using a torque wrench, which is essential for an accurate tightening force. However, the characteristics of the torque wrench have not been fully verified. Therefore, we aimed to clarify the factors affecting the torque with a focus on beam-type torque wrenches, which are the main types of wrenches. Methods The torque values generated by beam-type torque wrenches from eight manufacturers were measured using a torque gauge. To investigate the influence of the location of the beam relative to the scale, measurements were performed with a scale aligned with the trailing edge, center, and leading edge of the beam respectively. Additionally, measurements were taken at 90°, 60°, and 30° to examine the effect of the angle at which the examiner read the torque value. Under each condition, a single examiner applied the recommended torque to each manufacturer's screws five times in a clockwise direction. The average measured torque, standard deviation, bias, and coefficient of variation were calculated and compared accordingly. Results Wrenches from six manufacturers demonstrated excellent accuracy for measurements at the center of the beam (bias within ± 4%). For measurements at 90°, equipments from five manufacturers displayed excellent accuracy (bias within ± 7%), and seven showed excellent repeatability (coefficient of variation ≤ 2%). Conclusion The scale should be aligned with the center of the beam and read from 90° while using a torque wrench. The accuracy and repeatability torques generated by the wrenches differed according to the manufacturer, scale width, scale line width, beam width, and distance between the scale and beam center. Based on these results, we suggest that a torque wrench must be selected after determining the difference in the structure of the torque wrench.

Discrete modular serpentine robotic tail: design, analysis and experimentation

Robotica ◽  
2018 ◽  
Vol 36 (7) ◽  
pp. 994-1018 ◽  
Author(s):  
Wael Saab ◽  
William S. Rone ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Dynamic Models ◽  
Design Analysis ◽  
Degree Of Freedom ◽  
Legged Robots ◽  
Design Parameters ◽  
Inertial Loading ◽  
Forward Kinematic ◽  
The Impact ◽  
Accuracy And Repeatability ◽  
Two Degree Of Freedom

SUMMARYThis paper presents the design, analysis and experimentation of a Discrete Modular Serpentine Tail (DMST). The mechanism is envisioned for use as a robotic tail integrated onto mobile legged robots to provide a means, separate from the legs, to aid stabilization and maneuvering for both static and dynamic applications. The DMST is a modular two-degree-of-freedom (DOF) articulated, under-actuated mechanism, inspired by continuum and serpentine robotic structures. It is constructed from rigid links with cylindrical contoured grooves that act as pulleys to route and maintain equal displacements in antagonistic cable pairs that are connected to a multi-diameter pulley. Spatial tail curvatures are produced by adding a roll-DOF to rotate the bending plane of the planar tail curvatures. Kinematic and dynamic models of the cable-driven mechanism are developed to analyze the impact of trajectory and design parameters on the loading profiles transferred through the tail base. Experiments using a prototype are performed to validate the forward kinematic and dynamic models, determine the mechanism's accuracy and repeatability, and measure the mechanism's ability to generate inertial loading.

Teaching Mechanism Calibration to Engineering Students

2014 ◽  
Vol 615 ◽  
pp. 171-176
Author(s):  
Ana Cristina Majarena ◽  
Jorge Santolaria ◽  
David Samper ◽  
Juan Jose Aguilar Martín
Keyword(s):  
Engineering Students ◽  
Kinematic Model ◽  
Calibration Procedure ◽  
Design Parameters ◽  
Test Accuracy ◽  
Practical Application ◽  
Mechanism Optimization ◽  
Kinematic Mechanisms ◽  
Accuracy And Repeatability ◽  
Mechanism Kinematic

A new practical application for teaching mechanism calibration to engineering students in senior undergraduate courses is presented in this paper. The modelling, characterization and calibration of kinematic mechanisms is performed. This application presents a special interest in kinematic mechanisms in areas such as industry and research. The application interface allows the students to carry out the different steps of the calibration procedure in an easy way, to change different variables and to analyze results. This application therefore presents an important utility as a teaching tool for the learning process and analysis of the different steps in the mechanism optimization. The application developed allows students: to design their own mechanisms and to analyze the mechanism workspace by changing some design parameters, to test accuracy and repeatability of mechanism components, to introduce the mechanism kinematic model, to evaluate the mechanism performance before calibration, to calibrate the mechanism and, finally, to analyze the improvement in the system accuracy.

Experimental Investigation on the Friction Coefficients for Different Materials, Lubrication Conditions and Coatings in Bolted Joints

2020 ◽  
Author(s):  
Dario Croccolo ◽  
Massimiliano De Agostinis ◽  
Stefano Fini ◽  
Giorgio Olmi ◽  
Francesco Robusto ◽  
...  
Keyword(s):  
Bolted Joints ◽  
Design Parameters ◽  
Bolted Joint ◽  
Treatment Change ◽  
Friction Coefficients ◽  
Actual Application ◽  
Iron Aluminum ◽  
Torque Wrench ◽  
Zinc Coatings ◽  
Lubrication Conditions

Abstract The present paper investigates the influence of several design parameters on the frictional response of a bolted joint, involving screws from strength grades 8.8 to 12.9, with black oxidization coating or zinc coatings. The experimentation deals with different underhead and nut materials (cast iron, aluminum), lubrication conditions (dry, lubricated, two different threadlockers: medium and strong), roughness condition in the underhead (cast, machined, painted, underhead washers) and cosidering also the effect of repeated tightenings. The friction coefficients of the actual application, retrieved based on the relevant operating parameters, are needed to support a correct design. The experimentation has been carried out by a purposely developed specimen, consisting of two parts: an instrumented sleeve, with a double array of strain gauges capable of sampling both the axial preload and the underhead torque, and interchangeable underhead washers. The testing apparatus is provided with a device which allows preventing undesired rotation of the washers. The washer material and surface treatment change among the different specimen sets. The tightening torque is applied by means of a 10-120Nm digital torque wrench. The collected data have been processed by the tools of ANoVa. Such tools allowed assessing the significance of each factor, as well as related interactions.

Numerical and experimental analysis of fluid–fluid interaction and flow through micro clearance to estimate leakages in a fuel injection pump

2016 ◽  
Vol 231 (11) ◽  
pp. 2054-2065
Author(s):  
Balasakthivel Kamaraj ◽  
Shankar C Subramanian ◽  
Baskaran Rakkiappan
Keyword(s):  
Fuel Injection ◽  
Engine Oil ◽  
Emission Spectrometry ◽  
Design Parameters ◽  
Engine Fuel ◽  
Injection Pump ◽  
Lubrication Oil ◽  
Fuel Injection Pump ◽  
Flow Through ◽  
Accuracy And Repeatability

It has been observed during the operation of the diesel engine fuel injection pump that the fuel and the lubrication oil leak through the working clearance between the piston and the cylinder bore and mix with each other. The leakage of lubrication oil to fuel (OtF) leads to injector nozzle coking and emission, which necessitates the automotive industry to design a robust fuel injection pump to meet stringent emission norms. Similarly, the leakage of fuel to lubrication oil leads to depreciation of lubrication property of the oil, thereby reducing the life of engine oil lubricated components. In this research, the leakage flow through this clearance gap was studied using the numerical simulation tool, Ansys CFX, to estimate the volume flow rate of lubrication oil to fuel and fuel to lubrication oil. Pressure and drag effects are two important mechanisms that drive the leakage process. The simulation was carried out for various design parameters such as clearance, clearance taper and speed, and experiments were performed to determine the lubrication oil to fuel and fuel to lubrication oil flow rates. The diluted samples collected from fuel and lubrication oil tanks were analyzed using ICP-AES (inductively coupled plasma – atomic emission spectrometry) for calcium and barium element tracing. Calibration was performed on the ICP bench to study the accuracy and repeatability of the test sample analysis method. The results of numerical simulations and experiments were compared for various design parameters. The proposed analysis could serve as a valuable aid in the fuel injection pump development process.

Determining Accuracy and Repeatability of Torque Through Powered Equipment

2017 ◽  
Author(s):  
Scott Hamilton ◽  
Benjamin F. Hantz ◽  
Jason Wright
Keyword(s):  
Axial Load ◽  
Calibration Method ◽  
Flange Joint ◽  
Physical Strength ◽  
Industry Standards ◽  
Torque Wrench ◽  
Industrial Assembly ◽  
Bolted Flange ◽  
Accuracy And Repeatability ◽  
Joint Assembly

This paper explores torque wrench accuracy, one source of the overall inaccuracy associated with bolted flange joint assembly. The accuracy and repeatability of various pneumatic torque wrenches were tested and analyzed. Pneumatic torque wrenches were benchmarked against a hydraulic wrench which has a lower perceived bolt load scatter. The testing was performed on two mock-up flanges, NPS 8 Class 150 and NPS 16 Class 300 raised-face flanges with spiral-wound gaskets. The analysis compares the accuracy and repeatability of the following: each tool versus its manufacturer’s claims; duplicate models of the same tool; and overall tool type (pneumatic or hydraulic) versus another tool type. Because accuracy is closely related to tool calibration, torque wrench calibration method and frequency are also discussed. There are several methods of applying axial load through torque that have been used within the industrial assembly of Bolted Flanged Joint Assemblies (BFJA’s). The most common tool used within the industry is the manual torque “clicker” wrench which traditionally allows an assembler to reach 600ft/lbs. While companies make wrenches that achieve higher amounts of torque, they are harder on the assembler to use so other tools, such as hydraulic and pneumatic torque wrenches (Powered Equipment), that require less physical strength are used instead. This paper will discuss the accuracy and repeatability of pneumatic and hydraulic wrenches and compare them to the manufacturer’s/industry standards.

Optimal design of manipulator parameter using evolutionary optimization techniques

Robotica ◽  
2009 ◽  
Vol 28 (3) ◽  
pp. 381-395 ◽  
Author(s):  
B. K. Rout ◽  
R. K. Mittal
Keyword(s):  
Optimal Design ◽  
Differential Evolution ◽  
Dynamic Models ◽  
Optimal Parameter ◽  
Optimization Technique ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Evolutionary Optimization Techniques ◽  
Accuracy And Repeatability ◽  
Uncertainty In Design

SUMMARYA robot must have high positioning accuracy and repeatability for precise applications. However, variations in performance are observed due to the effect of uncertainty in design and process parameters. So far, there has been no attempt to optimize the design parameters of manipulator by which performance variations will be minimum. A modification in differential evolution optimization technique is proposed to incorporate the effect of noises in the optimization process and obtain the optimal design of manipulator, which is insensitive to noises. This approach has been illustrated by selecting optimal parameter of 2-DOF RR planar manipulator and 4-DOF SCARA manipulator. The performance of proposed approach has been compared with genetic algorithm with similar modifications. It is observed that the optimal results are obtained with lesser computations in case of differential evolution technique. This approach is a viable alternative for costly prototype testing, where only kinematic and dynamic models of manipulator are dealt with.

scholarly journals Factors Affecting Torque of Beam Type Implant Torque Wrench 

2021 ◽  
Author(s):  
Yuji Sato ◽  
Junichi Furuya ◽  
Tokiko Osawa ◽  
Akio Isobe ◽  
Myu Hayashi ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Beam Width ◽  
Factors Affecting ◽  
Tightening Torque ◽  
Torque Wrench ◽  
Screw Breakage ◽  
Beam Type ◽  
The Difference ◽  
Torque Values ◽  
Accuracy And Repeatability

Abstract Background: Screw breakage and loosening are the most common mechanical complications in implant treatment. One of the causes is the excess or deficiency of the screw tightening torque; thus, the use of a torque wrench is a prerequisite for achieving an accurate tightening torque. Therefore, we focused on the beam-type torque wrenches, which are the main type, to clarify the factors affecting this torque.Results: The torque values of the beam-type torque wrenches for the eight manufacturers were measured using a torque gauge. For investigating the influence of the location of the beam placed on the scale, the measurement was performed with the scale aligned with the upper edge, center, and lower edge of the beam. Additionally, measurements were taken at 90°, 60°, and 30° to examine the effect of the angle at which the examiner read the torque value. Under each condition, a single examiner applied the recommended torque value of each manufacturer's screws five times clockwise. The average measured torque, standard deviation, bias, and coefficient of variation were calculated and compared. Equipment from six manufacturers demonstrated the best accuracy for measurements at the center of the beam (bias within ± 4%). For measurements at 90°, equipment from five manufacturers displayed the highest accuracy (bias within ± 7%), and seven showed the highest repeatability (coefficient of variation 2% or less).Conclusion: It was recommended that the center of the beam should be aligned with the scale and read from 90°, while tightening the torque wrench. The accuracy and repeatability differed according to the manufacturer, scale width, scale line width, and beam width, while the distance between scale and beam center was related to accuracy and repeatability. Based on these results, it was suggested that a torque wrench must be selected after grasping the difference depending on the structure of the model to be used.

Tissue section lifting for electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 86-87
Author(s):  
Adrian F. van Dellen
Keyword(s):  
Infectious Disease ◽  
Electron Microscopy ◽  
Tissue Culture ◽  
Organ System ◽  
Surrounding Tissue ◽  
Paraffin Sections ◽  
Surface Areas ◽  
Specific Determination ◽  
High Degree ◽  
Accuracy And Repeatability

The morphologic pathologist may require information on the ultrastructure of a non-specific lesion seen under the light microscope before he can make a specific determination. Such lesions, when caused by infectious disease agents, may be sparsely distributed in any organ system. Tissue culture systems, too, may only have widely dispersed foci suitable for ultrastructural study. In these situations, when only a few, small foci in large tissue areas are useful for electron microscopy, it is advantageous to employ a methodology which rapidly selects a single tissue focus that is expected to yield beneficial ultrastructural data from amongst the surrounding tissue. This is in essence what "LIFTING" accomplishes. We have developed LIFTING to a high degree of accuracy and repeatability utilizing the Microlift (Fig 1), and have successfully applied it to tissue culture monolayers, histologic paraffin sections, and tissue blocks with large surface areas that had been initially fixed for either light or electron microscopy.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

Sign in / Sign up

Export Citation Format

Share Document