Improvements in Pitch Chains and Chain Wheels.
Year: 1887

page_text: Date of Application, 4th Feb., 1887
Complete Left, 4th Nov., 1887
Complete Accepted, 9th Dec., 1887
Improvements in Pitch Chains and Chain Wheels.
We, HERMANN RANDHAHN, Engineer, of Eisenberg, and FERDINAND WILHELM
HERING, of Osterfeld, both in the Empire of Germany do hereby declare the nature
of this invention to be as follows:-
This invention relates to pitch chains and chain wheels used in place of pulleys
and belts or cords for the purpose of driving machinery.
The improved pitch chain consists of links, which may be either rectangular in shape
and section, or circular in section, and of the ordinary shape. Some of the links are
provided upon each side with a projecting pin, such links being connected together by
plain links.
According to the purpose for which the chain is to be used and the size of the
wheels round which it passes, a larger or smaller number of intermediate links is
used; for large wheels, and some kinds of machinery a larger number of intermediate
links up to ten or more being used, whilst for smaller wheels for hoisting or purposes
of the like kind, a small number, or even one intermediate link only, is preferable.
The chain wheels, round which the chain passes are firmly fixed upon the driving
and driven shafts, and have a central groove formed completely round their circum-
ference into which fit the perpendicular links of the chain, whilst the alternate
horizontal links lie upon rings, surrounding the circumference and adjoining the
groove. The projecting pins already described upon each side of the horizontal links
fit between two rows of teeth formed completely round each edge of the circumference
of the wheel, so that the chains are effectually geared to the wheels, whilst the teeth
serve to guide the chain in its place. The teeth are made wider at the roots so as to
fit and hold the pins upon the chain, whilst their points are so formed that the links
readily leave them as the wheels revolve.
The rectangular shape and section of the links is preferable, as they fit better into
the groove in the wheel, and work more safely, and for large wheels, or long chains,
the use of a larger number of intermediate links is preferable.
It is advisable to arrange the distance between the several pairs of projecting pins
upon the links so that they do not always fit between the same teeth, as by bringing

page_text: them constantly into contact with fresh teeth the wear is greatly equalized. In order
readily and quickly to take apart the chain and put it together again, one or more
solid links may be used, having one end forked and embracing the end of the adjoining
link. Both ends are bored to receive pins which couple them together and the ends
of which fit between the teeth of the chain wheel, as already described. A projecting
key is fitted into the pin at the centre of its length, which fits into a corresponding
notch in the solid end of a link, whilst the forked end of the adjoining link which
embraces it, has a similar notch in each branch of the fork, the notches in the latter
not, however, corresponding with that in the former when the links are in a straight
line or nearly so, but only when they have been bent sufficiently out of the straight
line, in which latter position the pin can be readily removed or replaced, for the
purpose of disconnecting the chain and reconnecting it again.
1
T
1005

page_text: We, HERMANN RANDHAHN, Engineer, of Eisenberg, and FERDINAND WILHELM
HERING, of Osterfeld, both in the Empire of Germany, 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 pitch chains and chain wheels used in place of pulleys and
belts or cords for the purpose of driving machinery. The improved pitch chain
consists of links, which may be either rectangular in shape and section, or circular in
section, and of the ordinary shape. Some of the links are provided upon each side
with a projecting pin, such links being connected together by plain links.
According to the purpose for which the chain is to be used and the size of the
wheels round which it passes, a larger or smaller number of intermediate links is used;
for large wheels, and some kinds of machinery a larger number of intermediate links
up to ten or more being used, whilst for smaller wheels for hoisting or purposes of
the like kind, a small number, or even one intermediate link only, is preferable.
The chain wheels, round which the chain passes are firmly fixed upon the driving
and driven shafts, and have a central groove formed completely round their circum-
ference into which fit the perpendicular links of the chain, whilst the alternate
horizontal links lie upon rings, surrounding the circumference and adjoining the
groove. The projecting pins already described upon each side of the horizontal links
fit between two rows of tecili formed completely round each edge of the circumference
of the wheel, so that the chains are effectually geared to the wheels, whilst the teeth
serve to guide the chain in its place. The teeth are made wider at the roots so as to
fit and hold the pins upon the chain, whilst their points are so formed that the links
readily leave them as the wheels revolve.
The rectangular shape and section of the links is preferable, as they fit better into
the groove in the wheel, and work more safely, and for large wheels, or long chains,
the use of a larger number of intermediate links is preferable.
It is advisable to arrange the distance between the several pairs of projecting pins
upon the links so that they do not always fit between the same teeth, as by bringing them
constantly into contact with fresh teeth the wear is greatly equalised. In order
readily and quickly to take apart the chain and put it together again, one or more solid
links may be used, having one end forked and embracing the end of the adjoining
link. Both ends are bored to receive pins which couple them together and the ends
of which fit between the teeth of the chain wheel, as already described. A projecting
key is fitted into the pin at the centre of its length, which fits into a corresponding
notch in the solid end of a link, whilst the forked end of the adjoining link, which
embraces it, has a similar notch in each branch of the fork, the notches in the latter

page_text: not, however, corresponding with that in the former when the links are in a straight
line, or nearly so, but only when they have been bent sufficiently out of the straight
line, in which latter position the pin can be readily removed or replaced, for the
purpose of dis-connecting the chain and re-connecting it again.
Referring to the annexed sheet of illustrative drawings,
Fig. 1 is a front view, and Fig. 2 a side view of driving gear provided with the
improved driving chain.
Figs. 3 to 7 inclusive are detail views hereinafter more fully referred to.
A chain according to this invention comprises chain links D (which may be of
rectangular section as in Fig. 3, or of ordinary section as in Fig. 4) provided with
pins or projections E that are preferably of round section.
These chain links D are connected together by intermediate plain links F, (as shown
in Figs. 3 and 4) of which there may be one or several between each link D, the
number varying according to the size of the chain wheels and to the object in view.
With large chain wheels and for hoisting apparatus in mines a large number for
example ten or more of the links F may be employed. With small chain wheels, and
for elevators, hoists, pulleys, and like applications one link F between two links D
may be found sufficient, but more than one may be employed if found desirable.
The chain wheels or pulleys G, (part of one of which is shown separately in section
in Fig. 5,) are mounted respectively on the driving shaft and the driven shaft. Each
wheel has around its circumference a groove H for the reception of the perpendicular
links F of the chain (i.e. those which lie in the plane of the chain); the groove H is
provided on both sides with ring surfaces K K.
The links at right angles to the plane of the chain are guided by the teeth L L the
pins of the links D engaging with these teeth in such a manner that the transmission
of power is effected by means of the engagement of the pins with the teeth L L the
said pins entering the spaces between the roots of the teeth.
The teeth are at their base spaced considerably further apart than is usually the
case in ordinary toothed gearing: and in order to provide for irregularities in the
spacing of the pins on the links D the teeth are high and pointed so as to facilitate
the entrance of the pins.
When the length of the links or the distance apart of the pins E is such that they
will not suit the pitch of the teeth, the pins will slip on the latier and thus stretch the
chain to the proper length, whilst the part of the chain which is too long and is
between the engaged pins of two of the links D will contract in proportion.
The driving chain illustrated in Fig. 3, has the advantage, by reason of the
rectangular shape of its links, of being properly guided into the corresponding groove
of the chain wheel.
When several intermediate links are employed, (which arrangement is convenient
for the sake of cheapness with long chains and large wheels), it is preferable to make
the distance between the centre lines of each pair of pins equal to a multiple of the
pitch of the teeth of the chain wheel, in order to be able, when shortening the chain,
to bring the shortened chain again into coincidence with the pitch of the teeth.
The pins will thus be caused to engage with different teeth thereby preventing
excessive wear thereof.
Figs. 6 and 7 show a modified arrangement of chain which has for its object to
enable the chain to be readily taken to pieces and put together again.
Each link M is forked and each of its ends is bored to the same diameter. In each
hole is arranged a groove, so situated that when two adjoining links lie in a straight
line, the grooves do not coincide but are somewhat askew in relation one to
another.
In the holes is fitted the pin N provided at its centre with a projection which is
of the same size as the grooves and is of a length equal to the thickness of the eye
end of the chain link.
On turning the two adjacent links in such a manner that the grooves are brought
opposite to each other, the pin can be pushed in, and if the chain be then allowed to
stretch itself the pin N will be firmly held in place in the middle groove.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. A pitch or driving chain in which links D connected by means of one or more
intermediate links are provided with lateral pins or projections E to enter between
and engage with teeth L L formed on chain wheels G such wheels being formed
at both sides with ring surfaces K K and intermediate groove H for the purpose set
forth.
2. The construction of individual links of a chain such as referred to in claim 1 of
rectangular form, for the purposes indicated.
3. In a pitch or driving chain with lateral projections, forming two such projections
by one pin N that serves to connect the forked end of one link M with the eye end of
another link such pin N being normally held in place when the links are in line by
means of a projection O and the arrangement being such that the said pin can only
be removed after the links have been turned into definite relative positions as set
forth.
4. Chain wheels substantially as described.
5. The gear shewn in and described with reference to Figs. 1 and 2.
Dated this 4th day of November 1881.
HERMANN RANDHAHN.
FERDINAND WILHELM HERING.