Improvements in Gear Case for Bloycles.
Year: 1894

page_text: Date of Application, 10th Apr., 1894-Accepted, 19th May, 1894
CUMI LEIE
Improvements in Gear Case for Bloycles.
1, ALFRED MARSHALL MOORE, 51 Fairmont Street Malden, Middlesex
County, State of Massachusetts, United States of America, Mechanic, 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 apparatus for protecting the mechanism which supplies
the motive power for bicycles, from dust, mud or other foreign particles which by
their presence not only create more friction but increase the wear of the operating
parts.
My invention consists in a gear-case, so-called, that is it is intended to enclose
within it the sprocket wheels and chain which constitute the running gear of a
bicycle. My invention is embodied in the special form and arrangement of the
several parts which go to form the gear-case as an entirety, whereby the device
may be made adjustable to suit bicycles of different styles as well as to make it
removable. In other words I have so constructed the various pieces that the
gear-case may be put on or taken off in a very short space of time.
The various adjustments and other characteristic features will be hereinafter
more fully set forth and explained.
The drawings herewith presented represent in Fig. 1 a side elevation of a gear-
case embodying my invention and applied to a bicycle frame in part.
Fig. 2 is a plan view of the gear-case.
Fig. 3 is a side elevation partly in section showing the several parts in their
relative positions, but disconnected for purposes of description.
Fig. 4 is a side and end elevation of the fastening device employed to attach the
gear-case to the frame of the bicycle.
In the drawings I have indicated at 2 the crank shaft of a bicycle with driving
sprocket gear at 3, the rear axle at 4 is fitted with the rear sprocket 5, while the
chain 40 interconnects the two as in general. The lower portion of the frame of
the machine is shown at 6, 61, 62, 6'. The gear-case is shown, as an entirety at 7,
and its purpose is to enclose the two toothed wheels or sprockets, as likewise the
chain, and thereby prevent dust or mud from lodging on the chain and being
carried to the sprockets with the result that friction is very much increased and the
parts wear out. By means of this gear-case the parts are so completely covered
that oil can be used with freedom and the friction greatly reduced. This gear-case
may be composed of any thin waterproof material as leatheroid, or it may be made
from thin sheet metals if so desired.
This gear-case is composed of five principal parts, an end piece 8 for the front
sprocket, and two interconnecting covers respectively upper 9 and lower 10, which
are curved at their extremities adjacent to the rear sprocket in order to serve as a
cover for the latter. Inside end-closers 12, 13 co-operate with the sprocket covers
to enable the gear-case to be put on or taken off while at the same time the sides
of the sprockets are completely concealed. In detail these several pieces which go
to make up the gear-case proper are as follows:-The front sprocket is covered by
a semi-circular hood 8, before alluded to, which is of a width to contain said
sprocket, while the central side portions 14 are recessed at 15 in order to allow the
hood to pass over and yet snugly fit the hub of the sprocket. To enclose the rear
sprocket, I have provided two curved covers 9, 10, which may be U shape or

page_text: otherwise in cross section in part adjacent to the sprocket, and are provided with
end lugs 16, 17 to receive a holding screw 18. The remaining portion of said
covers 9, 10, not employed in protecting the rear sprocket are made in the form of
a box 19, 191, rectangular in cross section and adapted to contain the chain.
To interconnect the hood 8 with these boxes 19, 191 screw-threaded bolts 20, 201,
are secured near the ends of said boxes which are of a size and shape to slide
within said hood, metallic hinged plates 21, 21' are rigidly attached to the hood,
while the free portion of these plates is slotted to engage the bolts 20, 20¹, and are
held fast thereto by nuts 23. This arrangement not only permits for end adjust-
ment, or telescoping of the gear-case to provide for different lengths of the chain,
but allows the hood to swing from off the sprocket and expose either the upper or
lower portion thereof. As this hood conceals only about one half the sprocket,
leaving the sides and the other portion of the periphery exposed, closers are
supplied. These closers are formed of parallel side pieces united by a connecting
web 24, while the unconnected parts are adapted to straddle the hood 8 and the
ends of the boxes contiguous thereto. These overlapping parts are confined
beneath ears 25, on the boxes and beneath the ears 26 on the hood. To further
brace and interlock these several parts, as an entirety, the web 24 is bent traus
versely at such an angle as will enable it to coincide with the surface of the
boxes 19 19 against which this rests and is here fitted with bolts 34 34. The
offsets 27 being slotted at 28 to allow of sliding adjustment of the parts.
The closer 13 for the protection of the periphery of the rear sprocket not
concealed by the covers 9, 10, acting conjointly, is similar in shape to the closer for
the front sprocket, except that the web 24' is fitted with a prong 30 which enters
an aperture 31 in the box 19; an ear 32 engages the edges of the closer 13 which
overlaps the covers 9, 10. Hence it will be understood that the several parts, as
above premised, when united, form a complete gear-case practically dust and mud
proof; the outer bounding surface being made up of the end portion of the hood,
the top of the cover 9, and the bottom of the lower cover 10, while the inside
bounding surface comprises the bottom of the box 191, the web 24, the top of the
box 19, and the web 24¹; furthermore as the gear-case fits snugly about the hubs
of the sprockets little or no foreign material can enter.
The gear-case is intended to be adjusted in position, so that the top portion of
the chain will approach very closely the upper part of said case, while that of the
lower portion of the chain, usually slack, is curved as shown in Fig. 1, to conform
to the drop of the chain or its deviation from a straight line.
The operation of applying a gear-case embodying my invention to a bicycle is as
follows: The several parts being disengaged as shown in Fig. 3. The chain is
first disconnected and taken off, and the ends inserted through the box portion of
the covers 9, 10, which are then positioned about the rear sprocket. The chain is
again united, after which the hood 8 is adjusted about the front sprocket and the
hinged plates inserted over the bolts 20 20' after which the nuts 23 are loosely
screwed up.
The bolt 28 is then employed to bring the ends of the covers 9, 10,
together some elastic substance being carried between the bosses 16, 17 to prevent
rattling. This part of the gear being properly adjusted about the hub of the rear
sprocket, the hood 8 is now thrust over the extremities of the boxes 19 19¹ until
the recess 15 rests snugly about the hub of the front sprocket when the nuts 23
are screwed home. Either of the closers may now be put in place; if that for the
front sprocket the overlapping edges are made to pass beneath the ears 25, 26, while
the offsets 27 are inserted over the bolts 34. The closer is now pushed towards
the hub of the sprocket until the desired adjustment is effected, when the nuts are
set up tightly. The closer for the rear sprocket is similarly positioned, except that
this piece is supposed to come in a fixed position every time, so the prong 30 is
made to enter the aperture 31 while the offset 35 engages the bolt 36, the over-
lapping edges hanging beneath the ears 32. In some instances the end-closer 26
may form a part of the upper cover 9 and this is of advantage since it reduces the
number of pieces, and enables the gear-case to be applied more quickly.. In lieu

page_text: of the positive engagement of the several parts of this device adapted for end wise:
adjustment and intended to telescope or slide upon each other, a flexible medium
after the manner of bellows may be substituted. This arrangement would serve
equally well, since the parts may be moved inwards or from each other, while the
mud and dust are excluded, the chamber or space in which the operating parts
move being still maintained tightly closed.
To provide for attachments of this gear-case to the frame of a bicycle in order
to maintain it clear at all parts from contact with the sprockets and with the chain,.
I have provided brackets or clamps 37, shown in detail in Fig. 4, while upon the
exterior surface of the gear-case are formed or affixed short offsets or rods 38..
The clamps consist of a screw-threaded rod 39 furnished at one end with adjustable
holding jaws 40 which grasp the frame of the bicycle. Transversely of the rod 39
are loosely mounted twin arms 41 curved at their ends to fit the offsets 38. Inter-
posed between said arms is an adjusting nut 42 which moves upon the rod 39. A
clamp-screw 45 serves to rigidly lock the outer ends of the arms from the offsets.
and likewise upon the rod 39. In this way any desired adjustment may be effected,.
since the rod 39 may be moved along on the frame until opposite an offset, when.
movement of the nut 42 up or down upon the rod 39 gives the desired level, when
the arms 41 may be swung about the rod 49 until the desired angle is attained..
The curved extremities are adjusted upon the offset, the screw 45 is put home
and the gear-case at this point is made fast to and rigid with the frame. In the
drawings Fig. 1, I have shown the gear-case attached to the frame at four different.
points.
When
The advantages of this gear case are primarily that mud and dust are excluded.
to a great degree and enables a free use of lubricant on the gearing. Furthermore
it is capable of adjustment for every type of bicycle and is easily removable, while
the sprockets are readily accessible by the removal of two or three nuts.
in position it forms a closed chamber, and since it may be made of leatheroid or
other light waterproof material, it adds little or no weight to the machine while at
the same time it is entirely noiseless.
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 gear-case for bicycles composed of a plurality of parts having adjustable
connections, so that said case may be shortened or lengthened to provide for
variations in distance between two revoluble wheels, substantially as explained.
2. The combination with a gear-case for bicycles composed of a plurality of parts.
which are adjustably connected, so that said case may be shortened or lengthened.
to accommodate variations in distance between the sprockets, of means for securing
said gear-case to the frame of a bicycle, substantially as described.
3. A gear-case, composed of a group of parts consisting of a hood, an upper
cover, a lower cover, and two end-closers adapted to interlock and form a chamber
to contain the two sprockets and the chain of a bicycle, the said upper and lower
covers being adjustably united to the said hood and said end-closers, substantially
as stated.
4. In combination with a hood, and two covers, upper and lower, two end-closers.
adapted for telescopic adjustment with respect to the covers, substantially as
specified.
5. In a gear-case, the combination with an upper cover in part a closed box, a
similar lower cover, both curved at their adjacent ends, and means for interlocking
the same, of a hood adapted to receive and slide upon the opposite extremities of
said covers, two closers to engage with the covers and hood, and mechanism for
adjusting and fastening together the various parts as a unit, substantially as
stated.
6. In a gear-case for bicycles the combination with two covering devices for
the front and rear sprockets, of two closed chain-boxes, the upper one of which is.

page_text: straight, and the lower one of which is bent to conform to the curvature of a slack
chain, and means for securing the said gear-case to the bicycle frame, substantially
as set forth.
Dated this 19th day of March 1894.
ALFRED MARSHALL MOORE.