To obtain the dynamic response characteristics of operators under vertical vibrations, we sought the correlations between the acceleration of a vibrator or a tractor seat and the acceleration of the waist, shoulder and head of operator seated on it. (1) Assuming that man-machine system was linear, we obtained the satisfactory results on human dynamic response charactristics by spectrum analysis. (2) Resonant frequencies of human body were in the low frequency area (under 10Hz). Namely, they were in the nearly 5Hz range at the waist and the head and nearly 3.5Hz range at the shoulder. But in a strained posture larger resonance appeared at the sholder in the nearly 9Hz range. (3) The transmissibility (the ratio of the body part acceleration amplitude to seat acceleration amplitude) remarkably decreased over 10-20Hz range and the values were under 0.1. The acceleration power spectral density (P. S. D) of the waist increased at the frequency affected by engine revolution, but the P. S. D of other parts hardly varied over 50Hz range.
The aim of this study was to find out the relationship between the slippage and the sinkage of wheels in tractor drawbar pull operations and a method to determine the potential sinkage of driving wheel through transient processes. Prior to the experiment, the theoretical discussions were introduecd based on some assumptions. Soil bin testing device facilty was constructed for the experiments, and was used during the test. Results of the experiments may be summarized as follows: 1) The transient phenomenon of slip-sinkage of tractor drive wheels in operation can be simulated as a first order linear damping system which is used in automatic control engineering. 2) With an increment of the slippage, the time constant of the slip-sinkage curve system becomes small. 3) The relationship between the slippage, s, and the potential sinkage, h0, can be expressed as a linear system. In this experiment, some unsatisfactory data ware resulted from non-homegeneity of soil compaction and the uneveness or irregularities of soil surfaces.
The method and the most important conclusions of this investigation are as follows: 1. High-speed Annular Shear Device KS-2 for laboratory use was designed and built by which soil shearing stress, normal stress, annulus sinkage and horizontal displacement are measured simultaneously and continuously under the shearing speed of about 1 to 600cm/sec. Fly-wheel rotates the turn table on which cylindrical soil bin is placed immediately. Shear head permitted friction-free vertical movement is prevented from rotating by side arm. This configuration turned out to be profitable to measure soil-shearing stress in high-speed shearing. 2. Thirteen variables such as internal or external soil-shearing stress (S or F), cohesion or adhesion (c or a), bulk density of soil (ρ), coefficient of viscosity of soil (μ), mean diameter of soil particles (D), mean diameter of annulus (d), section width of annulus (b), grouser height (h), grouser span (λ), normal stress (σ), shearing speed (V), annulus sinkage (Z), and horizontal displacement (J) were assumed to be indispensable to soil-annulus shearing. 3. Buckingham's Pi Theorem led f(π1, π2, …, π10)…|π1′, π8′| (1) in which π1=S/ρV2, π1′=F/ρV2, π2=h/b, πn3=b/d, π4=λ/d, π5=ρVd/μ, π6=D/d, π7=σ/ρV2, π8=c/ρV2, π8′=a/ρV2, π9=Z/J, and π10=J/λ and the nomenculature |π1′, π8′| means both π1′ and π8′ are exchangeable with π1 and π8. 4. Component equation of Eg. (1) π1c=fc(π2, π3, π4, π5, π6, π7, π8, π9, π10)…|π1c′, π8′| (2) in which π9 was assumed to be negligible and the bar denotes constant values was considered. Let π5 and π7 be eliminated on dry sand and soft clay respectively, then π1 sand=Const⋅f1(π7)+π8 sand…|π1′sand, π8′sand| (3) and π1clay=const⋅f2(π5)+π8clay.…|π1′clay, π8′ clay| (4) 5. In the experiment in which ρ and μ were held constant and the condition of Component Eq. (2) was satisfied, it was observed that the functions f1 and f2 were both exponential functions. 6. It was assumed that the component Eq. (2) could be obtained as the sum of Eqs. (3) and (4). Then π1c=k1π7m+k2π5n+π8…|π1c′, π8′| (5) in which k1, k2, m, and n are dimensionless constants. 7. If both sides of Eq. (5) are multiplied by ρV2, there results S=c+Kσ⋅V2(1-m)⋅σm+Kv⋅Vn |F, a| (6) in which m, n, Kσ and Kv are new soil values. The equation would be a extended equation of soil-annulus shearing considering shearing speed.
For studying the similitude technique of the soilmachine system, the long rectangular blades which the ratio of two side lengths of 1:3 were tested on dry sand and mud in a soil bin. It became evident fron the tests that there were not substantial differences between the actions of cutting or bulldozing by the blades and the results of former test of the horizontal penetration of the cones. And we found that 1) The relation R=A1Hk1 were obtained between the side length of the blade H and draft R and the mean values of k1 were 2.21 on sand and 2.12 on mud. The draft force was not affected by the density or hardness of sand in the range of this test conditions and it increased with the cutting depth on sand, but, on the contrary, the depth did not affect on mud and the moisture contents, that is, the hardness had direct effects. 2) The relation of the depth and the draft on sand was represented by R′=A2z′k2 and the mean value of k2 was 1.13. 3) The differences of the actions of the blades to soil due to change of the cutting angle α and β, did not affect to the draft force on mud except the case of the angle α on sand. 4) In addition to draft force R, side length of blade H, the specific weight of soil γ, the penetrating resistance p, the shear resistance τ, and the depth of blade z were included as the variables for the similitude studies of this system by the dimensional analysis, And Pi terms of these variables were ∏1=R/pz2, ∏2=γz/p, ∏3=H/z, ∏4=α, ∏5=β and the functional relationship of these Pi terms may be expressed as ∏1=f(∏2, ∏3, ∏4, ∏5) The both systems including the penetrating resistance p and the shearing resistance τ were considered as the another system and separated individually as p-system and τ-system to find which is the better variable for this system on similitude study. 5) There were the following relations between ∏1 and the other ∏ terms. ∏1=A6∏2k6, ∏1=A7∏3k7, ∏1=A8∏4k8 And further, it may be found that these individual formulas were able to combine to the product of each Pi terms as ∏1=A∏2k6, ∏3k7, ∏4k8, ∏5k9 Then, if the design conditions were satisfied, the similarity of this system would be valid and the values of ∏1 would be able to predict from the model tests. 6) But, there are a problem that the control of the soil strengths is very difficult and the design conditions are not satisfied easily, then, the distorted model must be used. 7) When the both model and prototype were tested on the same soil conditions and same depth, we had simpler relation between the distortion factor and prediction factor than on test under the same condition of ∏3, that is, z/zm=nH. On the test under the same soil and same dapth, ∏3 was distorted and distortion factor of this term β2 and the prediction factor δ2 on ∏1 terms may be represented as δ2=-β2-k7=nHk7 where nH was the scale length, k7 was the exponent shown in the above. Then, the draft force of protototype R was calculated from R=nHk7Rm Rm: Draft force on model blade
This is a report on how to make a seedbed by using harrowing rotors. Mainly the degree of pulverizing was examined when the revolving speeds of the harrowing rotors were varied with three types of harrowing tines being tried. 1) This method features combined application of the harrowing elements and partial harrowing of tilth. 2) Pulverizing pitch and cutting speed of the harrowing tine have shown a power functional relation among the weight mean diameters of the clod. 3) Between breaking ratio and non-dimensional term (Dw1-h/Pi-h, Vc-h/V1) related to the revolving speed of the harrowing rotor there existed an exponential relation. 4) Although the pulverizing performance of the soil was slightly affected, a good result was obtained either with h2 (knife tine) and h3 (L-tine). 5) The harrowing element viewed from the pulverizing extension index has shown a higher value when shielded and was found that it gave a higher pulverizing efficiency. 6) The working performance and power performance have been influenced considerably by shielding or non-shielding. 7) If the mechanical operating condition were taken as a factor when the three elements, vis., the tilling rotor, shield, and harrowing rotor, were jointly used, the weight mean diameter of the clod of the seedbed may be expressed by the following equations: Dw2=[1-(A2B2π2)]×(A0⋅Pin1)⋅CT-n2, (mm) or Dw2=[1-(A3B3π3)]×(A0⋅Pin1)⋅CT-n2, (mm) where π2=Dw1-h/pi-h, π3=Vc-h/V1, Dwi-h=(A0⋅Pin1)⋅CT-n2
We performed the motion and time study of harvesting and transporting when used the cart for transporting and used the hand-basket that is customary working, by using model cucumber plan ting, The results were as follows: (1) we prepered three kinds of designated model cucumbers which resemled real ones in size and hanged them on a model device together with other model cucumbers. After that, we let a person pick the designated model cucumbers. The accuracy of picking incresed with increase of picking time but thers was a limit in the increase of picking accuracy. There was not very much change in the accuracy when the number of the designated model cucumbers was varied. (2) The picking motion of the picker was classified into three groups, viz, the standing posture, the half sitting posture and the stooping posture. The time of picking increased with increase of the number of designated model cucumbers and the increased time was roughly equal to the increase in time due to half sitting and the stooping motions. (3) when the number of the designated model cucumbers increased, the number of times of each posture also increased. Above all the increase in the case of half sitting posture was remarkable. (4) The coefficient of variation of time of the half sitting and the stooping postures was increased with increase of the number of designated model cucumbers. It showed that the time of above two postures became irregular with increase of the number of designated model cucumbers. The relation between the number of designated model cucumbers and the coefficient of variation of time of the standing posture was not clear. (5) The motion and time study showed no difference between applying a cart and the customary working methed. Therefore it may be concluded that the motion of a picker could not be simplified by using a cart.
1. The existing centrifugal distributors appear to attain uniform distibution of particles by means of placing the feed position whithin the free radius, making the angle between feed pipe and blade by 90 degrees, and putting the flight direction of particles at random. The writers made an attempt to widen the distribution of particles and distribute them uniformey by fixing the flight position of particles through controlling their fiight direction and falling position. 2. In order to make flight direction exact, the influence of important factors, especially feed position, number of blade, peripheral velocity, kind of fed material, presence or non-presence of blade cover, angle between feed pipe and spinner, and angle between feed pipe and blade, were exemined with a model. 3. The drag angle and the flight direction of particles conincide with theoretical values without suffering the influence of kind of fed material, peripheral velocity, and feed position at all. 4. The number of blade exerts great influence upon the drag angle and the flight direction. The minimum number of necessary blades is decided by the peripheral velocity and the feed position. 5. The angle between feed pipe and blade exerts an influence upon the drag angle. The drag angle tends to increse when the angle between feed pipe and blade is near 90 degrees. The initial velocity of particles is influenced by the degree of the angle between feed pipe and spinner. Generally the bouncing of particles occurs on the spinner when the angle is over 45 degrees. The flight direction can not be controlled in this condition. This phenomenon is changed according to the kind of fed material. 6. The writers made a test machine with several feed positions which could distribute particles in several density curves with normal distibution and attained the resultant of them, on the basis of the above results. Wide and uniform distribution of parfictes was obtained by this new machine without suffering the influence of kind of fed material and spinner speed.
In order to improve separating performance in pneumatic grain casing, the authors studied and experimented air velocities and separation of grains in the casing having a diffuser, which was theoretically shaped and was combined with an air chamber. Results of our study are as follows; (1) The diffuser casing gave a uniform air speed distribution and the effect of separation was increased. The optimum angle of diffuser divergence was 6-8°. (2) The air chamber attached further raised, the effectiveness of the diffuser. (3) We recognized a correlation between the air speed deviation and the separating efficiency of grains.
The passing period of tea leaves in a continuous type tea steaming machine was surveyed by the activable tracer experiment which is one of the nuclear power technique. In this experiment, gold was used as a activable tracer. The distribution of the passing period of tea leaves was analyzed statistically by the equation of the gamma distribution. Among three angles (2.0°, 4.8°, 6.5°) of the steaming drum tested, the mean passing periods of tea leaves became shorter by increasing of the angle However, the variance of the distribution of the passing period showed the smallest value at 4.8° and became larger on the both sides of 4.8°. The mumber of revolutions of the agitating hand in the steaming drum per minute did not affect the mean passing periods of tea leaves significantly when it was in the range of 320rpm to 560rpm. But the variance of the distribution showed the smallest value under the condition of 460rpm and became larger on the both sides of 460rpm. The charging rate of tea leaves to the steaming machine influenced on the distribution of the passing period. When the over or under amount of tea leaves for the optimum amount of the tested machine was charged, the variance of the distributions of the passing periods became larger.
As the preliminary study for the analysis of management work in the dairy barn, the author investigated the relationships between increasing rate of heart rate and relative metabolic ratio (RMR) by static and dynamic muscular works. The following experiments were carried out: (1) Measurement of heart rate and RMR of an adult male subject when he walks on the belt tread mill as dynamic muscular work. (2) Measurement of heart rate and RMR of the subject when he holds one or two heavy things by various postures as static muscular work (Fig. 2) The results obtained are as follows. 1) There was a very close positive correlation between increasing rate of heart rate and RMR in each case of static and dynamic muscular works (Table 1). The relation of these two indexes could be shown by a linear equation Y=aX+e (Y: increasing rate of heart rate, X: RMR, a: coefficient, e: error). 2) Numeral values of coefficient a varied with a character of work, that is, the coefficient a of static muscular work is larger than that of dynamic muscular work. 3) For static muscular works, the coefficient a varied a little with work posture, and was from 11.92 at bending forward posture (1) to 7.95 at sitting posture. The suthor intends to determine the value of coefficient a of management work in the dairy barn.