Improvements in Drive Chains.
Year: 1898

page_text: Improvements in Drive Chains.
I, ERNST GUSTAV HOFFMANN, of 43, Beech Street, Barbican, London,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in drive chains adapted for chain
driven cycles as well as for driving various machinery and apparatus.
The chain according to my invention is provided with a roller against which
the teeth of the sprocket or like wheel bear and antifriction balls inserted between
both the rollers and the links and independent rivets or pins on which the parts
work said rivets or pins being grooved with a series of races for a series of balls
which are maintained in same and so prevented from moving laterally.
The grooves or races in the pins or rivets are preferably of the same curvature
as that of the balls and bear on a considerable surface of same. The interior
faces of the roller and the openings in the links of which the chain is com-
posed are not grooved but bear only upon the balls at a small point of same.
The pins or rivets are adapted to be passed into the rollers and links and to
be secured in further links outside same which in one form of the invention act
as the connecting link only as distinguished from the working link.
Means are provided at one point of the chain for opening one of the con-
necting links to separate the chain preferably by causing the pins or rivets to
be held in key-hole slots in same.
To prevent the balls of the end series from falling out when the chain is thus
opened they may be held in the chain by a slotted metal strip bent around and
holding said balls in the slots of same as in a frame or cage. The arrangement
is also adapted for what are known as "block
Dated the 11th day of Rohr 1898
33
chains.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, W.C.,
Chartered Patent Agent for the Applicant.

page_text: easily understood.
Fig. 1 is a sectional plan of several links of a chain.
Fig. 2 is a side elevation.
Fig. 3 is a detail to show one side of the chain opening connecting link, its
pin or rivet, and an arrangement for holding the balls during withdrawal of
the rivet.
Fig. 4 is a similar view shewing the opposite connecting link and its corre-
sponding arrangement of parts.
Fig. 5 is a sectional plan shewing two ends of the working links with which
the above connecting links engage.
Fig. 6 is an elevation of a pin or rivet of the chain opening link.
Fig. 7 is an elevation of a pin or rivet of the ordinary links.
Fig. 8 is a plan of a piece of metal employed in holding the balls in the chain
opening link and
Fig. 9 is a side elevation of one of the chain opening connecting links.
The chain illustrated is made up of plates a forming the connecting links and
plates forming the working links the latter having between them at each end
a bushing forming a roller c though a block forming a part of the links b may
be used in place of the roller as is well understood.
In Fig. I is shown a portion of a chain in which occurs the link provided for
the opening of same and such link is provided out of one of the connecting
links and is formed of the plates a¹ as shown.
The plates a (and of course the plates a¹) on each side are united by pins or
rivets which pass through openings in the plates b and through the rollers c.
The pins or rivets are provided with a number of grooves a shown in Figs. 6
and 7 such grooves having a rounded surface formed practically of the same
curvature as that of balls f forming a series of races for such balls which by
reason of the curve of such grooves are provided with a large wearing surface
on the pin. Suitable plane surfaces are left between each groove e to separate
each series of balls. The plates 6 of the working links and the rollers both
bear on these balls in the interior of the openings of same such openings being
plain curved surfaces without any races so that the balls have a bearing only
on a small point of such surfaces.
Each end of the pins or rivets of the ordinary links are reduced in diameter
as shown in Fig. 7 and when in position in the chain with the balls in place are
rivetted over as shown at g at either end of Fig. 1.
In the case however of the links that require to be opened the pins or rivets
are formed as shewn in Fig. 6 with one reduced end which may be rivetted on
the plate a¹ as shewn in Fig. 1 and a head g² adapted to pass into a keyhole
shaped opening a² Figs. 1, 2, 3, 4 and 9 of the plate a¹ which will be held by
same when the narrow end of such opening is brought under the head g³ as it
would be when the chain is in tension.
The arrangement preferred is to arrange the plates a¹ so that one of the slots a
comes at the opposite end to the one on the other side as shown in the drawing
whereby each pin or rivet d is firmly held by one of the plates.
To open the chain the two working links connected by such plates a¹ are
forced toward each other so as to press the headed ends of the pins or rivets

page_text: into the larger end of the keyhole slots a³ which will enable one or both of the
plates a and its attached pin or rivet to be withdrawn.
In the ordinary course the withdrawal of the pin or rivet d will cause it
to bring with it the balls f and as this would necessitate their being replaced
separately when putting together the chain an arrangement is employed for
holding the balls in their races during the withdrawal of the pin and so that they
remain on such pin as shown in Figs. 3 and 4, Fig. 5. showing the ends of two
working links from which such pins have just been withdrawn. The device
employed for this purpose consists of a piece of thin sheet metal h Fig. 8 provided
with a number of long slots i one slot being for each of the series of balls.
This is bent around the balls and pin so that the balls project for a part of
their diameter through the slots i before the pin is placed in position in the
chain and thus holding the balls to the pins whenever it is desired to remove
the latter. The ends of the plate may overlap as shown in Figs. 3 and 4 at j
such ends serving to strengthen the plate. They are of such a width that they
will lie in the ordinary space left between any two of the balls. The retaining
device is shown in position in the chain in Figs. 1 and 2.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is::
1. In a drive chain, a pin having grooves in same balls carried in such grooves
and a bushing surrounding the balls and pin and forming a roller of the chain
substantially as described.
2. In a drive chain, a pin, a series of grooves in same, plates forming links in
the chain through openings in which the pin passes, a bushing forming a roller
between said plates and surrounding the pin, and balls in the grooves of the pin
forming an antifriction bearing for both the plates and roller substantially as
described.
3. In a drive chain, a grooved pin, a series of balls in said grooves and a
plate having a series of slots, one for each series of balls said plate being bent
around the pin and balls so that the latter project through the slots but are
held by the plate in their grooves on the pin substantially as described.
Dated this 10th day of November 1898.
PHILIP M. JUSTICE,
Chartered Patent Agent,
55 & 56, Chancery Lane, London, W.C.,
For the Applicant.
PHILIP M. JUSTICE,
Chartered Patent Agent,
55 & 56, Chancery Lane, London, W.C.,
For the Applicant.