National Institute of Occupational Safety and Health, Japan
Experiments by Photoelasticity on Several Types of Lighting Clamps
SH-1958-3-1
T.HAKAMAZUKA
: This paper presents the results of model experiments by photoelasticity made on several types of lifting clamps and these experiments have revealed the patterns of the isochromatic lines, the isoclinics lines, the lines of principal stress.
The stress distributions of these types of clamps in following five models of material handling are also disclosed.
1. one or several steel plates, horizontally
2. one or several steel plates, vertically
3. cylindrical material
4. channel or angle steel
5. ingot steel
On the Strength of Steel Ring
SH-1958-3-2
Y.MORI and I.MAE
: We have tested the strength of the steel ring and found that the experimental values conform with the theoretical values calculated by the limit design method, as regards the yielding load in the ring.
Then, about an annealed SS41 steel ring which has a inside dia. four time as much as the dia. of the round steel bar, the yielding load Pe in kg may be expressed as follows :
Pe = 8 d2
where d is the dia. in mm of the round steel bar. Furthermore, the breaking load Pu in kg for the same ring may be expressed approximately as follows :
Pu = 60 d2
Therefor, the safe load Pai for the same ring can be expressed as follows :
Pal = 4 d2
The Influences on the Visual Acuity by Glare and the Necessary Intensity to See an Object in the Presence of Glare
SH-1958-3-3
R.TANAKA
: Glare must be considered as two adverse factors in safety i.e. disability and discomfort.
The former is that interferes with visual acuity and the latter is that discomforts one with brightness.
The author measured the decrease of visual acuity and the necessary increase of intensity of illumination to see an object, in the test with an incandescent lamp as a glare in front of an observer.
Then it was found that the nearer a glare source is, the higher the necessary minimum intensity of illumination is, and the lower the visual acuity is.
On Safety Provisions in Labor Agreement
SH-1958-3-4
H.MATSUZAWA and C.GOTOH
: Analyzing the provisions relating to safety in the labor agreements of thirty selective companies with more than 1,000 employees among various industries in Japan, the authors obtained the following classification :
1. Type following after the standard recommended by Japan Federation of Employers' Associations and the like.
2. Type solely depending on
a) governmental regulations
b) shop regulations
e) production committee
3. Type avoiding definite statements.
The general features of the above three types are as follows :
(1) The provisions have not been drafted through positive discussions between the two parties concerned
(2) The provisions are conventional and non-concrete
(3) Many provisions were copied from governmental regulations
(4) Many provisions failed to meet the requirements as an agreement which is specified by the authority
