It is shown that a higher accuracy in measurement of optical path difference between two domains than conventional techniques can be obtained by a double diffraction interferometer. The interferometer consists of similar components to a Schlieren system but contains a fine wire instead of a knife edge. The object space is occupied by a test brock which is made up of three chambers between two optical flats. Optical path difference is given by adjusting air pressure in one of them. Light intensity is measured by a photomultiplier tube behind a pinhole in an opaque plate at the image plane. When the wire is travelled along optical axis, the intensity varies in various manner that depends on fractional part of the ratio of the optical path difference to the wave length. Because the relations among the fractional part, position of the wire and the intensity can be theoretically found, the former one may be deduced from measured results of the latter two. Experimental results show that observation error of the fractional part in the new technique can be restricted within 0.02.

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The early fracture of P 20 carbide tool was investigated on the interrupted turning of steel (S 45 C) under the four kinds of the tool/work engagement and disengagement conditions in order to get the basic idea for the development of carbide tools of the higher early fracture resistance. The results were discussed using the cutting speed (V)-feed rate (F) diagram, and the mean normal (σ) and shearing stress (τ) on the rake versus cutting temperature (T) diagram under the steady state condition. The influence of the tool/work engagement conditions on the tool fracture was found primarily dependent upon the feed rate (F), on the other hand, the influence of the tool/work disengagement conditions on the tool fracture was dependent upon the cutting speed (V). The experimental fracture criteria of P 20 were discussed on σ-τ-T map transcribed from V-F diagram. It was concluded that the early fracture can be classified into the following three mechanisms, such that ; 1) tool/chip welding-fracture in the lower temperature region, 2) mechanical stress-fracture in the medium temperature region and 3) plastic deformation-fracture in the higher temperature-higher pressure region.

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The arc of tool-work interface and cutting force pulses from individual cutting edges in surface belt grinding were investigated to clear the role of elastic deformation of a contact wheel. The arc was measured directly from a workpiece obtained by a quick-stop device enabling the work to be suddenly disengaged from the abrasive belt. The results revealed that the radius of this arc for a comparatively soft contact wheel (durometer index: 35) became even 10-50 times that of the undeformed wheel. The force pulse results were obtained using a high-frequency piezo-electric dynamometer, showing that the active cutting space became greater and inversely the cutting force smaller with reducing the rigidity or increasing the elastic deformation of the contact wheel. This result appearing to be an important factor for high performance of belt grinding was proved by a theoretical consideration on the basis of a grinding model using the radius of arc measured.

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The threaded bars twist around their axes when they are pulled axially. This phenomenon is one of the causes of loosing bolt nut units in use. In this paper, authors report the experimental result of the values of four frictional torques, i. e. frictional torque T_sf between threaded parts of bolt nut units in loading, ditto T_st in unloading, the torque T_wf between nut and its bearing surface in loading, and ditto T_st, in unloading. And they propose that bolt nut unit looses in use when T_st > T_wf and T_wl > T_st simultaneously. Besides, they measure the loosing angle of nuts in the repeated tensile loads, following after J. N. Goodier and R. J. Sweeney.

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This study is on a moving robot with the tactile sensor, which is able to autonomously find the path to move. The f unction of the tactile sensor which is installed on the moving robot was described in the previous report. This paper describes the control method of the robot and the path-finding algorithm. The algorithm actively uses the information concerning obstacles obtained by the tactile sensor during the movement of the robot. The robot has three control modes; it can move straight forward or backward, or can make a turn on the spot. These modes are commanded by a mini-computer. The path-finding algorithm described here may be called as "Groping method". This algorithm consists of the following three sub-algorithms as "Normal searching", "Decision of steering clear of obstacle" and "Reverse searching". The abilities of the robot are shown by the experimental results.

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When a solid body slides on a vibrated surface, effective friction is apparently reduced. This paper treats such a case as a solid body sliding on a surface vibrated elliptically, though in the previous paper it is vibrated rectilinearly. If the velocity ratio V (the velocity of the solid body X to the vibration velocity A_ω) is nearly zero, then it is shown afteranalytical calculations that the coefficient of effective kinetic friction, μ_k' gradually approaches a value that is not zero, when the frictional surface is vibrated elliptically with a component in the normal direction. Under certain conditions, however, , μ_k' becomes an equivalent negative value ; and therefore, in the present paper it should be called "the negative coefficient of the effective kinetic friction". When it is elliptically vibrated without a component in the normal direction, μ_k' gradually approaches zero and is not negative. However, equivalent effects on friction are larger than in the case of rectilinear vibration. Thus, there are some substantial differences between them. These theoretical results have also been confirmed by experimental studies. The analytical calculation in this paper is to be applied to the effects of vibration on friction as a general theory.

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The effect of shape of tool point on the cutting-ability has been studied for various sized drilling. The ratio of chip-weight to the chip-weight plus burr-weight of a drilled part is defined for the cutting-ability; the higher ratio means the higher cutting-ability. 0.02% C steel was selected as the testing material and its thickness was adjusted to be equal to the drill-diameter in order to keep the shape of a drilled part same and compare the cutting-ability becomes worse with decrease of diameter, but it becomes better contrary with further decrease of the diameter. This phenomenon is independent of the drilling speed and of the condition of pre-heat-treatment of the testing material. The most outstanding finding in this work is that the improved cutting-ability in the case of very small diameter drills is not so deterrented even when their tool points are fairy dull. This fact suggests that a generally accepted drilling-mechanism is not applicable to the micro-drilling probably because of rather different plastic deformation due to its smallness of drilled-depth per one revolution and the smallness of drilled part. The difference in the plastic deformation seems to be the reason why a drilling with very small drills show a good cutting-ability with little burr.

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In order to improve the reliability of seismic sensors used in the seismic safety equipments, this paper examines and estimates the influential factors on the frequency characteristics of the mechanical sensors through classifying the approximate equations of their simplified motion and comparing numerical solutions with experiments under the sinusoidal vibration. Both slipping and rolling or rocking motion of such mechanism as steelballsupporting plate, inversed inertia, etc., represented approximately by a motionless zone and a non-positive spring constant and/or especially by an ideal relay system, give good detecting characteristics of acceleration, i. e. flat pass in a low frequency range and sharp cut off of 12 dB/oct in a higher range. The slip motion lowers the initial load constant and consequently raises the detecting sensitivity as much as a kinematic friction. The perfectly rocking motion, more sensitive than the above because of the phase in harmony with exciting force, is quite reliable on the frequency response. The cut-off frequency is estimated by only the function of a distance between the center of inertia and the contact point. As the experimental results have justified all the theoretical data, the simplified equations and their few factors are of use for the design of the acceleration sensors.

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In order to operate effectively a mixed-model production line on which a variety of models of the same general product is intermixed, it is essential to determine the sequence in the flow of models. For a practical large-scale mixed-model production line which is subject to system variability, this paper develops a heuristic procedure which iteratively improves a given sequence into the optimum or near-optimum solution by inserting a model of the sequence into other positions and interchanging model pairs of the sequence. By extensively discussing solution times, the quality of solutions obtained by this procedure, and the probability that a given initial sequence reaches the optimum solution, the paper has shown that the procedure generates the optimum and near-optimum solutions highly effectively. Run times grow approximately as M^2.2 with the size (M) of models, and linearly with the number of stations.

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The measurement of the pitch error is widely used for the accuracy test of a gear. However, the unevenness of the measured result is a big problem. Also, there are some unknown natures in the single pitch error, and in the accumulative pitch error and the pitch variation which are numerically obtained from the data of the single pitch error. For clarifying these natures, the formulas of the pitch errors are induced from the Fourier expansion formula that expresses the transmission error of a gear. Then, the meanings, problems and utilities of the pitch errors are studied with these formulas. As the result, the following things are obtained. 1) In the accumulative pitch error, there is a complicated problem of mixing the suspected lower order component and the setting position of the feelers are very important in the measurement. 2) In the pitch variation, there is the nature of selectivity of the components by the number of the order and the value of the variation has close relationship to the amount of the dynamic load on the gear tooth only for the lower order component of the transmission error. For the more effective use of the measurement, the discriminating method of the suspected lower order component from the total components of the accumulative pitch error is introduced and the necessity of developing the measurement method that does not affected by the roughness of the tooth surface is explained.

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In this paper, the torque and the angle control methods, which are most usually used in screw tightening, and the newly developed gradient control method are compared and a policy for the selection of them is discussed. For this purpose a tightening test machine which can test the above three methods is designed and manufactured. Firstly, using the machine, fundamental experiments are carried out taking account of the following factors : pitch of screw threads (A), surface treatment (B), lubrication (C) and tightening speed (D), and it is pointed out that the effect of the lubrication condition is especially significant. Secondly, in the case where the factors (A), (B) and (D) are fixed and the factor (C) is with or without lubrication, the three control methods are compared, and it is found that the dispersions of clamping force become greater in order of the angle, the gradient and the torque control methods. Finally, a new tightening method is presented, in which bolted joints are tightened with the torque or the angle control methods using the value of the torque or the angle found in the case of tightening them with the gradient control method, and this method is confirmed to be efficient.

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In order to investigate the fracture process of electrodeposited metal film and the mechanism of crack initiation, fatigue tests of the electrodeposited copper single crystal film were performed. The electrodeposited single crystals with crystal orientation of {001}, {110} and {111} were prepared by vacuum evaporation and electrodeposition. The crack initiation was originated at extrusion and intrusion, whose cross-sections cut by an ultramicrotome were observed by electron microscope. A unique pattern in thin film was found in which the extrusion and intrusion initiated along the common slip plane on the surface and on opposite sides. Initiation form of fatigue cracks can be roughly estimated from the crystal orientation. However, as is seen in the specimen with {110} plane and <001> stress axis, crack growth was sometimes remarkably suppressed due to action of Cottrell's sessile dislocation. The growth rate of cracks propagated from a notch by shearing stress was found to be constant. Crack initiation process accorded with stochastic process, and frequency of initiating cracks depended upon crystal orientation.

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The purpose of this study is to investigate the influences of the grinding conditions, the rubber hardness and the peripheral surface of the contact wheel upon the grinding temperature and the affected layer in the belt grinding. The results obtained are as follows :
(1) It is found that the well-known theory on the grinding temperature by using grinding wheel can be applied to the belt grinding, considering the elasticity of the coated abrasive belt and the contact wheel. The calculated values of the peak temperature at contact zone between the coated abrasive belt and the workpiece coincide fairly with the experimental results.
(2) The peak temperature at contact zone and the depth of affected layer in the serrated contact wheel are lower than those in the plain-faced one and decrease with a decrease of the rubber hardness and the shape factor.

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The purpose of the present study is to improve an accuracy by decreasing the fluctuation of translation speed of a moving carriage in an automatic laser interferometer for the calibration of standard scales up to 2 m. The translation system is analyzed of the carriage and a new device is introduced in order to decrease the speed fluctuation. Teflon slide bearings, which have a relatively low and velocity dependent coefficient of friction, are used as the device in place of the two of the eight roller bearings of the carriage. In consequence, the rate of the speed fluctuation obtained by the device is shown to become considerably smaller than the rate by only the roller bearings and the value to be less than 0.4% at the typical speed 100 mm/min. Decreasing the speed fluctuation, the standard deviation is experimentally estimated to be less than 0.04 μm in repeated measurements of a one millimeter line interval of a standard scale.

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