An Improved Device for Altering the Speed or Ratio of Transfer in Belt or Rope Driving Gear.
Year: 1898

page_text: Date of Application, 19th Jan., 1898-Accepted, 19th Feb.,
1898
COMPLETE SPECIFICATION.
An Improved Device for Altering the Speed or Ratio of Transfer in
Belt or Rope Driving Gear.
I, THEODOR BERGMANN, of Bergmann's Industriewerke, Gaggenau, Baden, in the
Empire of Germany, Manufacturer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention relates to a device for altering the speed or ratio of transfer in
helt or rope driving gear by means of adjustable and engageable stretching or
tension rollers and is shown in the accompanying drawings in Figures 1-5.
In Figures 1 and 3 a belt changing gear is shown in elevation and plan with
three belts, and in Figures 2 and 4 in elevation and plan a similar one with four
belts, that is to say for three and four different speeds respectively.
In this belt changing gear, the engagement of the various transfer mechanisms
takes place by a stretching of the belts which hang loose on corresponding step
pulleys, by means of one or more stretching or tension rollers which by axial adjust-
ment are adjusted each time to a belt giving the desired ratio of transfer, and
pressed on the same. Z is the driving and O the driven shaft, on which in the case
of three different ratios of transfer there are mounted three pairs of different step
pulleys I, II, III as well as three loose hanging belts n¹ n³n³. A stretching or tension
roller t which is arranged about in the centre between the two step disc spindles
Z and O and which when in a disengaged condition lies somewhat above the
highest belt is revolubly mounted on the end of a fork T' which is mounted on
an axially adjustable spindle N¹. The spindle N' is supported in two bear-
ings N2 N3, its support, the bearing N2, being not direct but in the hub or boss of a
lever 93 which is revolubly mounted in the bearing N2, and the said spindle N¹
is prevented rotating by means of keys or splines engaging in grooves in the lever
hub and can only revolve with the latter, but on the other hand is axially ad-
justable. On turning the lever q³ the spindle N¹ is turned with it and also the
fork T with the stretching roller t¹.
For axially adjusting the spindle N and the stretching or tension roller t¹, the
spindle N is coupled by means of a cross head w³ with an elbow lever q, which is
connected by means of a link q¹ with a hand lever P. By the adjustment of the
latter into any of the three positions p³, p² p³ shown in Figure 3, the shaft N1
may be so adjusted that the stretching roller t¹ lies over any one of the belts n¹ n² n³.
The throwing into gear of the stretching or tension roller t¹ on to the belts, that
is to say the turning of the spindle N¹, takes place by means of a lever P³ which
is connected by means of a link q² with the lever g³ mounted on the spindle N¹.
According as the lever P3 is brought into the position shown in full lines or in
dotted lines in Figure 1, the stretching roller will be either removed from the belt
or pressed on the same.
A somewhat modified form of construction of the belt changing gear is shown in
Figures 2 and 4 in the use of four belts n³n and two stretching rollers t¹ t² which
are arranged opposite one another in such a way that they either come to stand

page_text: over the centre of the first and third or the second and fourth belts in such a way,
that a stretching roller stands opposite each two smallest step discs in order that
when the belts are thrown into gear the periphery as far as possible of the smallest
step is embraced by the belt in order to obtain greater adhesion.
A movement of the hand lever P3 from the central position to p³ 2 is transmitted
by a link q² and the lever ³ to the spindle N¹ and in one case the stretching roller t¹
and in the other the roller t2 is pressed on a belt whilst the other roller is always
removed from the belt.
By adjusting the shaft N¹ in a similar manner to that hereinbefore described
the stretching rollers t¹ 2 may be adjusted by the same elbow pull to the adjacent
belts. Further the ratio of transfer may be employed as desired and instead of
belts, ropes may of course be employed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. A belt or rope changing gear characterised by a stretching or tension
roller (¹) being connected by a fork (T) with a spindle (N) adapted to be operated
in such a way that said roller may be pressed on any one of a group of belts, the
roller being axially adjustable with the shaft to enable it to be brought over a
required belt for altering the ratio of transfer, substantially as herein before de-
scribed.
2. A belt or rope changing gear characterised by two stretching or tension
rollers (2) being connected by means of forks (T¹ T2) opposite one another with a
spindle (N) adapted to be operated in such a way that on the said spindle (N¹)
being turned forwards or backwards, one or the other tension roller is brought into
engagement with and caused to bear on any one of a group of belts for altering
the ratio of transfer, the said spindle (N) being pushed axially to bring the roller
over a required belt, substantially as hereinbefore described.
3. In the herein described arrangements of belt or rope changing gear, the
mounting of the spindle (N¹) by means of splines or longitudinal keys in the nave
of its operating lever (g), which nave is provided with suitable key grooves to
receive said splines and is revolubly mounted in a fixed bearing (N2 Figure 4), sub-
stantially as herein before described.
Dated this 18th day of Ionum 1008
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.