IMPROVEMENTS IN CHAINS
Year: 1880

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for
an Invention of "IMPROVEMENTS IN CHAINS." A communication from
abroad by James Mapes Dodge, of Chicago, in the United States of America.
PROVISIONAL SPECIFICATION left by the said Sydney Pitt at the Office
of the Commissioners of Patents on the 15th June 1880.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN CHAINS,"
[A communication from abroad by James Mapes Dodge, of Chicago, in the United
States of America.]
This Invention has for its object improvements in chains.
For this purpose, in chains composed of alternate single and double bar links,
curved projections are combined with the bars or plates composing the links
to form tho bearings at the articulations of the links, and take the wear and strain
usually enforced upon the studs or bars that perform the office, also of tying
together the bars composing the double links. The said projections are so combined
and operating as to form male and female members of an articulate joint which
are capable of separation, but only when the parts are turned into a position which
they cannot assume during the working of the chain.
Sometimes the links are so made that each link is composed during a portion of
its length of two, and during the rest of its length, of one bar, and has its double
and single ends provided respectively with curved projections constituting
respectively female and male members of an articulate joint. The union of such
links forms a chain, the parts of which may be uncoupled only when turned out of
their working positions.
Also according to this Invention chains are constructed, the links of which are
coupled or jointed together, to give the chain the requisite flexibility by means of
bearing lugs on the end of one of two adjacent links which embrace projections on
the other links, and the said lugs and projections work together with a superficial
rolling motion. Provision is made for the disengagement of the parts.
For the purpose of working upon sprocket wheels having teeth that enter the
links, a detachable chain is made, the links of which are composed of two side
pieces and one cross piece, and the jointures or articulations are composed of curved
bearing projections working together as already described.
'

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sydney Pitt in the Great Seal Patent Office on the 14th December
1880.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN CHAINS."
A communication from abroad by James Mapes Dodge, of Chicago, in the United
States of America.
This Invention has for its object improvements in chains.
For this purpose, in chains composed of alternate single and double bar links,
curved projections are combined with the bars or plates composing the links to
form the bearings at the articulations of the links, and take the wear and strain
usually enforced upon the studs or bars that perform the office, also of tying
together the bars composing the double links. The said projections are so combined
and operating as to form male and female members of an articulate joint which are
capable of separation, but only when the parts aro turned into a position which
they cannot assume during the working of the chain.
Sometimes the links are so made that each link is composed during a portion of
its length of two, and during the rest of its length, of one bar, and has its doublo
and single ends provided respectively with curved projections, constituting
respectively female and male members of an articulate joint. The union of such
links forms a chain, the parts of which may be uncoupled only when turned out of
their working positions.
Figures 1, 2, 3, and 4 of the annexed Drawings are respectively a face view,
side view, longitudinal central section, and cross section of a chain constructed
according to this Invention. Figure 5 is a partial longitudinal section, showing
inore particularly how the links may be taken apart or uncoupled; and Figure 6 is
a similar sectional view, showing a modified form of chain, in which a somewhat
different manipulation of the parts is necessary in the uncoupling operation.
At Figures 7, 8, 9, and 10 I have shown respectively in top or face view, sido
view, longitudinal vertical section and longitudinal horizontal section, a modified
form of the Invention; while at Figures 11, 12, 13, and 14 I have shown by a
similar set of views another modification of the improved chain and at Figures
15, 16, and 17 by a top view, side view, and vertical longitudinal section, I have
shown still another modification of the Invention.
In the several Figures of each of the forms of chains shown the same parts will be
found designated by the same letters of reference.
In Figures 1 to 5 inclusive, A, A, represents the double bar links, and B, B, the
single bar links.
The single links are in this case shown as being of cast malleable iron of the
form clearly illustrated, and are made with lateral projections Cat or near cach end,
that are adapted to ongage, in a manner to be presently explained, with certain
projections on and the connecting rivets of the two bars of the double links, whilo
the latter are composed as shown of two bars or castings a, a, of the forms shown,
cach of which has an inwardly projecting rim or flange like device D at each end.
E are the rivets by means of which the bars or castings u, u, of each doublo link
are permanently united, and which are also utilized (in preference to the use of somo
auxiliary device for that purpose) for retaining the projections C in place within
or in a bearing condition against the projections D of the bars of the double links.
The bearing projections C of the single links it will be seen are each in form
substantially like one half of a short cylindrical tube, while the projections D of
the double links are also semi-tubular in shape, but having the curvature of their
interior surface about in conformity to the curvature of the exteriors of the
devices D, and the rivets E are of about a sufficient diameter to fill the semi-circular
concavity of the projections C.

page_text: By preference, the side picces or plates a of the double links are formed with a
rim-like flange projecting from their outer surfaces to render said plates as strong
as possible with a minimum amount of stock, but the form of these and other parts
is not of course material, so long as the chain embraces the principle of construction
of the Invention.
The single links could of course be stronger than each of the side bars a, a, of the
double links, since each single link has to withstand the same strain to which tho
two bars a, a, of each double link are subjected in the aggregate.
In a chain made as shown in theso Figures, and as first described, the single and
double links will be free, it will be seen, to articulate or turn about axes of motion
about coincident with the axes of the rivets or rivetting studs E to an extent more
than sufficient for any purposes for which such chain may be used, without any
liability or even possibility of any separation of the joints or articulated parts.
At the same time if it be desired for any purpose to separate the parts of the
chain at any one of its articulate points, such separation may be readily effected
by turning the parts adjacent to the joint at which it is desired to uncouple into a
relative position, such as seen at Figure 5, for when turned into this position the
coupled links may be separated by moving them apart in the manner and direction.
indicated by the dotted lines at said Figure.
As it is this position only of the parts (or in a similar one except at the link B
being turned to the same angle with the link A in an opposito direction) that any
separation can occur, and as this position can never be assumed by the chain in a
working condition, it follows that while the parts may be designedly uncoupled in
the manner shown and described, there is no liability of any casual separation of the
links whilo the chain is in a working condition.
It will be observed that while in any practical application of the chain of which
such chains are capable, would not require the turning of the links on their hinges
to a greater extent than a half circle sweep, the links of the chain shown may have
any two links turned relatively through an arc about equal to three quarters of a
circle before the parts can assumo a relation in which the uncoupling will be
possible.
It will be understood that in the pulling strain to which the chain is subjected,
the bearings between the jointed parts occur where the exterior semi-cylindrical
surfaces of the projections O of the single link come into contact with the internal,
similarly shaped surfaces of the projections D of the double links, and that in any
and all relative movements of the link (about their axes of articulation) the whole
frictional wear will come on these surfaces of contact; and since these surfaces can
necessarily be of greater extent than it would be possible to make any pivotal stud
or pintle passing through the bars a, a, it follows that the form of articulating
devices shown is much stronger or more durable than those beretofore usually
employed in the class of chain to which the Invention relates..
The rivets or side bar securement studs E serve also; it will be seen, to keep the
projection devices Cup to their working positions within the socket-like devices D,
or, in other words, prevent the devices and the links carrying them from backing
out of their bearings when the chain is slack.
AB, however, these studs E have to perform only this function, and that of tying
together the bars a, a, they need not be made very strong nor large, and hence the
side bars a, a, need not be materially weakened by the holes necessary for the
accommodation of these rivets or studs.
In lieu of having the single links shaped and relatively arranged in the manner
shown and first described, each of the semi-cylindrical hollow projections C may
have its edges extended in a substantially straight direction somewhat further, as
seen at Figure 6, in which case the separation of the parts cannot be effected
in precisely the manner shown at Figure 5, but can only be uncoupled by
the relative movement of three adjacent links into the positions shown at

page_text: '
the same principle of operation described as being peculiar to the Invention, as
illustrated in the preceding Figures; and the same is true of the other forms of chain
shown in the succeeding Figures of the Drawings. In Figures 7 to 10 inclusive,
the supplemental feature of the projections F are added to the side bars a, a, of the
double links to perform the function of holding or keeping the projections C of the
single links up to their bearing with the projections D, leaving the rivets or studs E
in such case to perform only the function of uniting the bars a, a, to form the
double link. In Figures 11 to 14 inclusive, the links are modified in form from
those first referred to by the addition of supplemental projections g, g, to the single
links, which projections, as shown, are rib-like, are arranged concentrically to tho
curved bearing surfaces of the devices C, and serve to come against the exterior
of the curved projections D of the double links to prevent the backing out, so to
speak, of the devices C from their bearing in D, thus leaving the studs E (as in the
last preceding mentioned form of links) to perform only the functions of uniting
the bars a, a, of the double link.
In Figures 15 to 17, the articulate or joint portions of the chain are about similar
to thoso of the first described chain, but each link has one single and one double
end, so that the chain is composed of duplicato links.
In other words, the chain instead of being composed, as in the other described
cases of alternate double and single links, oach double link containing two fomale
members and each singlo link two male members of the devices, by means of which
the joints or articulations of the parts are created, made up of duplicate herma-
phrodite parts, each link having a male member of a coupling at one end and a
female member at the other end.
The Invention may be applied to chains having the links multiplied widthwise
of the chain in the manner common to chains of the class to which the Invention
relates whenever it is desirable to increase the width of the chain.
Also, according to another part of this Invention, chains are constructed, the links
of which are coupled or jointed together to give the chain the requisite flexibility
by means of bearing lugs on the end of one of two adjacent links which embraco
projections on the other links, and the said lugs and projections work together
with a superficial rolling motion. Provision is made for the disengagement of tho
parts.
Figure 18 is a top or face view, Figuro 19 a side or edge view, Figure 20 a
longitudinal sectional view, and Figure 21 a horizontal section (at x, x, Figure 19)
of a chain made according to this part of the Invention.
Figure 22 is a side view showing the mode of uncoupling the links, and
Figure 23 is a sido view showing a modification which will be presently explained.
In tho several Figures the same parts will be found designated by tho samo letter
of reference.
A represents the single, and B the double link of the (chain, the latter being
made of two plates or bars b, b, united by the usual cross-tie studs or rivets c.
Each of the bars or plates 6 of the double link is formed or provided near each
end and on its inner face with a peculiarly shaped projection d, leaving within its
contour a sort of recess or depression e for the accommodation of a projecting lug
(of a given form) on one side near the end of each single link, and each of said single
links is formed or provided on each side with [two such [lugs f, such lugs being
located at or near the end of each side of the link, as clearly shown (see Figures 19
and 21.) When the parts are coupled together and in a working position the lugsƒ
will each be located and will work within one of the recesses e, and will bear at
its inner straight edge i (seo Figure 19) against the curved edge ; of the rib-liko
projection on the inner face of the side plate 6 of the double link.
And in any turning movement of the link relatively this straight bearing
edge of lug f will roll in one direction or another on the curved edge j of rib d.
The structure and conjoint arrangement of these parts will be best understood
by reference to Figure 19. By this construction and combination of parts it will
be seen the jointed links, instead of moving with the friction and wear consequent

page_text: to the usual hinge-like joints of chains of the class to which the Invention relates,
move with a sort of rolling or anti-frictional movement of the bearing devices, thus
enabling the chain when at work to operate with much less friction and to run a
given time under a given strain with very much less wear and with less consumption
of driving power.
Whenever it may be desired to uncouple any two links (for any of the usual and
well known purposes of detachable chains) by turning the parts desired to be
detached into the positions shown at Figure 22 they may be separated as illustrated
in that Figure.
It is for this purpose of detachability that the throat or opening is left at 8.
Wero the rib-like projections & made without any break in their contour (so as to
entirely surround the lugs f) the parts of the chain, after having been once put
together, and the rivets of the double link fastened, could not of course bo
uncoupled.
•
'
It will therefore be seen that, if desired,, the chain may be made non-detachable,
and so as to embody a part of the Invention without containing this other feature
of said Invention.
In the modification of the Invention shown at Figure 23 the lugs ƒ³ instead of
having straight working edges are curved, as seen at 1, so that the two surfaces
of the joint devices which come to a bearing against each other are curved
as seen.
It will be seen that in a chain constructed as above described, the frictional wear
and strain being distributed, as shown, over long bearing surfaces, and the motions
of the bearing parts being that of one rolling on the other instead of turning ono
on the other, as in the case of the socket and pintle of a hinge-like joint, tho chain
will enduro more strain and longer wear with a given amount of stock in tho
structure that can possibly be endured in a chain made according to any of the
heretofore practised modes of construction.
This improved chain in either a detachable or non-detachablo form possesses
many and great advantages over chains as heretofore made, especially for heavy
work, where the chain is subjected to great-strain and wear.
It may of course be made of any desired size and pattern of links, may have the
links duplicated widthwise of the chain to increase the width merely, and may be
varied in many details of the parts without losing the principle or advantages of
the Invention.
Another part of the Invention relates to chains for working upon sprocket
..wheels.
For the purpose of working upon sprocket wheels having teeth that enter the
links, a detachable chain is made, the links of which are composed of two side pieces
and one cross pieco, and the jointures or articulations are composed of curved
bearing projections working together as already described.
Figure 24 is a top viow; Figure 25 is a sido or edge view; Figure 26 is a central
vertical section, and Figure 27 is a central horizontal section of the chain, and in
the several Figures the same parts will be found designated by the same letter of
reference.
Each link is composed, as shown, of two side bars a, a, and a connecting cross-
bar b, located near two immediately opposito ends of the side bars; each cross
bar b serving in the chain as an end bar to each of two adjacent links.
In other words, in a series of links forming a chain, through each link has
apparently two side bars and two end bars (as common to most rag chains)
there aro in reality only half as many end bars (or cross bars) as there are sido
bars.
.
On the outer surfaces of the bars a, a, near two immediately opposite ends, are
two curved projecting ribs or bearers-c, c, and-on-the inner surfaces near the other
two ends of the said side bars are two curved projections d, d, between which and
shoulder-like projections e; e, are occasioned-recesses-ff, and-when-the parts of tho
chain are united in a working condition the projections c, c, are accommodated within

page_text: the recesses ff, and their convex 'surfaces bear on and work against the concave
surfaces of the rib-like projections d, d.
The disconnected ends of the bars a, a, of the link have cut outs (of a sort of
semi-cylindrical or U shaped contour) as clearly illustrated at g, and these ends of
said bars, it will be noticed, are somewhat nearer together than the opposite ends,
which are connected by the cross bar b.
This arrangement of the bars a, a, and this conformation of the link permits the
disconnected ends of the side bars of each link to be placed within inner faces of
the said bars near their connected end, in the manner shown, with the cross-bar b
partially within the cut outs g to prevent these cut ends of the side bars from
backing out from the bearings, and with the curved bearing projection c, c, in their
respective recesses and in engagement with the curved bearing surfaces of the
ribs d, d. Ati, i, on the inner faces of bars a, a, near where these bars are connected
by cross bar b are cut-aways or depressions such as shown, the object of which
is to permit the adjacent disconnected ends of the side bars of the next link to be
turned round far enough to effect an uncoupling of the links.
The necessary position of the parts for this uncoupling is illustrated at Figure 28,
where it will be seen that the link A. may be moved away from link B in the
direction of the arrow, and that but for the depressions i, i, to accommodate tho
projections c, c, the links could not have been turned in the relative positions in
which they are shown in this Figure.
The detail shapes, proportions, and sizes of the links and their parts may of
course be more or less varied without departing from the described principle of
construction by which, while the parts are capable of separation when turned out
of their working positions, and while they may turn relatively in the manner and
to the extent of the usual articulated chains of the class to which the Invention
relates, said parts are so jointed that at the turning points they work with bearings
of greater superficial surface and greater strength and durability than can possibly
be attained to in detachable rag-chains, such as heretofore made and used. The chain
links may in each case be stamped out of wrought iron or made of brass or :
malleable cast iron.
What I claim as new and desire to secure by Letters Patent, without restricting
the claim of Invention to the precise forms of parts, is,—
First. In a chain composed of articulated bars running in the direction of its
length and arranged alternately, singly, and doubly, substantially as set forth, the 3
articulations of the parts by means of curved projections at or in the vicinity of the
ends of the links, said projections being so combined and operating as to form male
and female members of an articulate joint which are capable of separation, but only
when the parts are turned into a position which they cannot assume during the
working of the chain.
Second. In a chain composed of links or bars running in the direction of the
length of the chain, and alternately single and double a link composed, during a
portion of its length, of two, and during the rest of its length, of one such bar, and
having its double and single ends provided respectively with curved projections
constituting respectively female and male members of an articulate joint, the
structure of the said link being such that the unison of two or more such links
will form a chain, the parts of which may be uncoupled only when turned out
of their working positions.
Third. A chain (see Figures 18 to 23) the links of which are coupled or jointed
together to give the chain the requisite flexibility by means of bearing lugs or their 5
equivalents on the end of one of two adjacent links, and embracing projections on
the other links, the said lugs and projections working together with a superficial
rolling motion as and for the purpose set forth.
Fourth. In a chain having the links coupled by means of lugs on one and
projections on the other working together, substantially as described in respect to 5
Figures 18 to 23, making provision for the disengagement of the parts, substantially
in the manner and for the purpose set forth.

page_text: Fifth. A detachable sprocket chain or rag-chain, the links of which are composed
of two sido pieces and one cross-piece, and the jointures or articulations of which
are composed of curved bearing projections working together in substantially the
manner shown and described in respect to Figures 24 to 28.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand and
seal, this Seventh day of December, in the year of our Lord One thousand
eight hundred and eighty.