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på denna ville han anföra de med »S K F» märkta
cigaretter, som deltagarna i lunchen bjudits på.
Han tog för givet, att dessa cigaretter skulle bliva
lika uppskattade som alla övriga artiklar med
samma märke.
Lunchen avslutades med ett fyrfaldigt leve för
SKF, varefter gästerna begåvo sig i väg, en del
till Windsor för att bese Kungl. Slottet, de övriga
till Konungens Garden Party i Buckingham Palace.
S. J. Aries.
SYNOPSIS OF CONTENTS
Power Savings by means of Antifriction
Bearings
As the question of power economy with the use-of
antifriction bearings is very extensive, the author has had to
confine himself to treat in detail of but two branches
where anti-friction bearings have been introduced.
Railways are the first to be discussed. In Sweden, where
during the last ten years extensive trials with ball and
roller bearings in locomotives and railway carriages have
been carried out, it has been found that the running
security with these types of bearings is practically absolute.
It has been ascertained that the following average savings
in coal consumption are possible in a country with a
climate resembling that of Sweden:—
For locomotives of the highest efficiency 4.25
kilogrammes of coal per 1000 tons kilometres, and up to 5
kilogrammes of coal per 1000 tons kilometres for locomotives
of less efficiency.
This saving represents 11% to 14% of the amount of
coal necessary for the propulsion of trains.
Hot rolling mills for iron and steel are the second branch.
Trials with these machines show a power saving of no less
than 45%. If the price of power is as low as 2,61 ore per
K. w. hour, this represents no less than Kr. 2: 10 per ton
of steel wire.
Finally, the author states that in these two branches
the bearing conditions are similar, and that the economy
figures can therefore be regarded as quite reliable. In other
branches this is not the case, as the bearing conditions
vary considerably. He gives, however, in the following
table the greatest and lowest savings effected during tests,
and the average figure suggested by the experience of
SKF engineers.
Saving in power after the introduction of antifriction
bearings.
Industries Largest saving according to
measurements Smallest saving according to
measurements Probable saving in per cent of total power
consumption
Mines................ 23,7 /o _ 5 /o
Machine Industries.... 35,9 /o 10 % 20 0/ /o
Cement Industries .... 40 % 8 % 18 0/ /o
Tube Mills only ...... 17 % 15 /o
Wood Working Ind. . . 33 /o •— 10 /o
Paper Industries...... 3° 0/ /o 7,5 % 11 /o
Flour Milling Ind..... 35 /o 12,2 % 14 /o
Sugar Refineries...... 25 0/ /o 20 o/o 15 0/ /o
Dairies.............. 25,5 /o 4 % 10 /o
Textile Industries .... 35.7 0/ /o 5,4 % 15 0/ /o
Leather Industries .... 19.3 /o 6,4 % 11 /o
Ground Threading Tap s of unusual
dimensions
The article gives a description of some staybolt taps
with ground threads manufactured and delivered by S K F
a few months ago to a large locomotive manufacturing
concern in Sweden. These taps were the largest ones ever
made with ground threads and special arrangements had
to be made to facilitate the grinding of them.
The length of the longest tap, see fig. 1, is more than
2 y4 meters, the others more than 1 y2 metres, and the
diameters vary between 26 and 36 mm. The pitch of the
largest tap is 11 threads in one inch, and the distance
between the threaded parts is 1,600 mm.
It is easy to understand the high degree of accuracy to
be observed in the manufacture of such a tap, when it is
borne in mind that these parts must be so placed in
relation to each other, that there is exactly one continuous
thread along the entire threaded part of the tap.
The author then goes on to show how necessary it is
to employ the taps at the same temperature as that, at
which they are manufactured. For instance, one of the
longest taps was cleaned in boiling hot soda water after
having been ground, and the deviation in pitch was then
found to be % of a thread between the threaded parts;
after the tap had cooled down to the temperature of the
room the deviation was less than 0,16 mm.
These taps are used in the manufacture of boilers for
locomotives for the Russian Government, and the
controlling engineers are extremely strict as far as accuracy
is concerned. Not until the SKF taps were used was it
possible to fulfil all requirements in this respect.
Fig. 2 shows staybolt taps of a unique design, as they
are probably the only taps ever produced with spiral
flutes. They are provided with an adjusting sleeve, by the
aid of which it is always possible to obtain a continuous
thread for various lengths of boilers.
Fig. 3 shows a nut tap 3%" in diameter and 500 mm.
long, and for the sake of comparison an ordinary tap,
illustrating the various demands anticipated.
SKF at Fairs and Exhibitions
The present number of Sfären shows several pictures
of fairs and exhibitions where SKF have exhibited.
Illustration No. 1 shows the SKF exhibit at the
International Flying Machine Exhibition in Prague.
The adjoining photographs are of the Motor Car Salon
in Turin, centre of the Italian motor car industry. The
SKF office in Milan exhibits ball bearing applications in
general, pulleys and transmissions, and demonstrates by
means of scales the lightness of our pulleys and hangers.
The photographs, drawings and motor car details also
serve to make the exhibit very instructive.
The following picture represents the SKF pavilion at
the exhibition at Reval, Esthonia.
As usual SKF had an exhibit at the Brussels Fair this
year (fig. 5) that attracted much attention.
The SKF representatives in Australia have recently
taken part in a large exhibition, the »Sydney Royal
Agricultural Show». At this Show SKF have always at their
command exhibit section No. 1 through which all visitors
must pass. This year there were 120,000 in one day.
The SKF exhibit at the Barcelona fair this year is shown
in fig. 7. Unfortunately the SKF letters have not been
placed in a conspicuous spot. It is gratifying to note the signs
fastened on various machines equipped with SKF bearings.
Fig. 8 shows an exhibit arranged by the SKF
representative in Portugal at the International Motor Car,
Aero-and Sports Exhibition at Oporto.
Finally, there is a snapshot from an exhibition in
Switzerland, where the SKF exhibit has attracted great attention.
WALD. ZACHRISSONS BOKTRYCKERI A.-B
©OTEBORG 1924
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