Improvements in Friction Clutches for Conveying Rotary Motion.
Year: 1892

page_text: Date of Application, 6th Oct., 1892
Complete Specification Left, 6th July, 1893-Accepted, 30th Sept., 1893 .
PROVISIONAL SPECIFICATION.
Improvements in Friction Clutches for Conveying Rotary Motion.
We, FREDERICK LISTER CROFT and HENRY CHRISTIAN, both of Lower
Ernest Street, Bradford, in the County of York, Engineers, do hereby declare the
nature of this invention to be as follows:-
This invention relates to improvements in that type of friction clutch for
conveying rotary motion in which a clutch piece or segment or segments is or are
expanded against the periphery of a cylindrical or annular recess and its object is
to increase the frictional contact that is to say the "bite or hold of the engaging
faces.
"
For this purpose we form an annular groove or grooves of wedge shape or taper
section in the periphery of said recess and we form a projection or projections on
said segment or segments of similar section to the said groove or grooves. By this
arrangement when the segment or its equivalent is expanded the projection or
projections thereon are wedged into said grooves and the frictional contact thereby
greatly increased.
To allow of the introduction of the clutch piece or pieces the shell forming the
cylindrical recess may be made in two parts suitably secured together.
As a modification the annular groove or grooves may be cut in the external
periphery of a cylindrical or other suitably formed portion of the clutch and an
external clutch piece or clutch pieces having a projection or projections to fit said
groove or grooves is provided.
Dated this 5th day of October 1892.
DRACUP & NOWELL,
Bradford, Agents.
COMPLETE SPECIFICATION.
Improvements in Friction Clutches for Conveying Rotary Motion.
We FREDERICK LISTER CROFT and HENRY CHRISTIAN, both of Lower
Ernest Street, Bradford, in the County of York, Engineers, 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 improvements in that type of friction clutch for
conveying rotary motion in which a clutch piece or segment or segments is or are
expanded against the periphery of a cylindrical or annular recess and its object is
to increase the frictional contact that is to say the "bite or hold of the engaging
faces.
"
For this purpose we form an annular groove or grooves of wedge shape or taper
section in the periphery of said recess and we form a projection or projections on
said segment or segments of similar section to the said groove or grooves. By this
arrangement when the segment or its equivalent is expanded the projection or
projections thereon is or are wedged into said grooves and the frictional contact
thereby greatly increased.
Reference is to be had to the accompanying sheet of drawings forming a part of
this Specification in which similar letters of reference indicate corresponding parts
in each of the figures.
Figure 1, represents a diametrical section of a clutch constructed in accordance
with our improvements and having two clutch blocks or segments.
Figure 2, is a side elevation of the same.

page_text: Figure 3, is a separate side elevation of the two clutch blocks, and Figure 4, is
a diametrical section of the same on the broken line a, b in the former figure.
The shell A is keyed on the shaft B and annular grooves C of wedge shaped
cross section are formed in its inner periphery. Projections D of a similar but
slightly larger section to the said grooves are formed on the clutch blocks E, E.
The driving piece F keyed on the shaft G drives the blocks E in the ordinary
manner and the mechanism for expanding and drawing the blocks together is of
the usual well known type as well as the arrangement provided for the adjustment
of the blocks to compensate for any wear that may take place.
It is obvious that when the clutch is used to drive a pulley the pulley may be
secured to the shell A in the ordinary way.
Instead of forming the clutch blocks in two pieces they may be formed in one
piece as shown by E¹ Figure 5. In this case we divide the shell diametrically to
enable the block to be introduced and we connect the two halves securely together
in any convenient manner.
As a modification the annular groove or grooves may be cut in the external
periphery of a cylindrical or other suitably formed portion of the clutch and an
external clutch piece or clutch pieces having a projection or projections to fit said
groove or grooves is provided, but we find this arrangement to be more expensive.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:
1. A friction clutch in which the engaging faces have each a wedge shaped
groove or projection formed in or on them and adapted to interlock with each other,
substantially as herein shown and described.
2. The combination with a clutch block or blocks having one or more grooves or
projections on the engaging face or faces of a shell or its equivalent the internal
periphery or engaging face of which is adapted to fit and interlock with the said
clutch block or blocks, substantially as herein shown and described.
Dated this 4th day of July 1893.
DRACUP & NOWELL,
Bradford, Agents.