Flexible Shafting is Employed.
Year: 1885

page_text: Flexible Shafting is Employed.
I, SYDNEY PITT of Sutton in the County of Surrey, Gentleman do hereby declare
the nature of this invention (a communication to me from abroad by Arthur
W. Browne of Westfield in the County of Richmond and State of New York one
of the United States of America, Mechanic) and in, what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
The first part of my invention relates more particularly to the method of
connecting the hand-piece casing and the tool-holder or chuck of dental and
similar engines with the supporting and driving connections thereof, respectively.
The objects of this part of my improvements are to permit of the ready
separation of the hand-piece casing and tool-holder or chuck thereof from the
supporting sleeve and driving shaft of the engine, whereby one style of hand-
piece may be readily removed or detached and another substituted in place thereof,
thus permitting, for instance, the removal or detachment of the usual straight hand
piece, and the substitution therefor of an angle hand-piece, or a hand-piece in which
the operating tool is driven at an angle relatively to the longitudinal line of the
hand-piece. In the straight or usual hand-piece the operating tool is driven in the
axial line of said hand-piece, as is well known to those familiar with the use of
dental engines.
The second part of my invention relates to improvements in the flexible shafting
or flexible couplings for shafting which is usually employed in dental and similar
engines to drive the chuck or tool-holder, and thereby also the operating tool; and
the object of this part of my invention is to provide a simple and efficient flexible
shaft, or a flexible coupling for stiff sections of shafting by which power is conveyed
from one driving shaft to another when they are not in line, or lie at an angle to
each other, or where one end of the flexible shaft may be fixed, and the opposite
end connected to a rotary chuck or tool holder or otherwise fitted to carry and
rotate an operating tool capable of being moved about to operate in various
directions.
The subject matter. claimed herein as of my invention is first particularly
described in detail as organized and constructed in the best ways now known to
me, and my improvements are then distinctly claimed in the summary at the close
of this specification.

page_text: Some of my said improvements so claimed by me may, of course, be used without
the others, and in organizations differing from that particularly shown in the
drawings, and in any connection in which they may be useful or for any purpose
to which they may be applicable.
In the accompanying drawings which form a part of this specification,
Figure 1 is a longitudinal central section of so much of the driving shaft, its
enveloping sleeve or sheath, and the rear end of a hand-piece casing, and tool-holder
or chuck thereof, as is necessary to illustrate the subject-matter claimed by me.
Figures 2 and 3 are detached views illustrating the slip joint or telescoping
driving connection between the rear end of the chuck or tool-holder of the hand-
piece, and the front end of the driving shaft.
Figures 4 and 5 show one form of spring catch which I may employ to secure
the rear end of the hand-piece casing on the front end of the sleeve or sheath of
the driving-shaft so as to permit the hand-piece to be readily detached while
securing it in place when in use.
Figure 6 is a view in elevation, showing the substitution for the usual straight
hand-piece, of a hand-piece in which the chuck which holds the operating tool, is
arranged to lie at an angle to the longitudinal line of the hand-piece and be driven
by suitable gearing in well known ways.
Figure 7 is a top or plan view of a portion of the shaft enveloping sheath or
sleeve, and the rear end of a hand-piece connected together.
Figure 8 is an enlarged view, showing a modification of the securing device
between the rear end of the hand-piece casing and the front end of the shaft
enveloping sheath, the modification consisting in substituting a sectional screw-
thread or ribs in place of the spring catch, shown in Figures 1, 4, 5, 6 and 7.
Figures 9, 10 and 11 are views more particularly illustrating this modified form
of readily detachable locking connection between the rear end of the hand-piece
casing and the front end of the shaft enveloping sleeve or sheath.
Figure 12 is a view in elevation of my improvements in flexible shafts or flexible
couplings for shafting: and
Figure 13 a similar view showing the shaft as operating while bent.
Figure 14 is a section through Figure 12 on the line 14, 14 of the latter.
Figure 15 is a view in elevation of a flexible shaft or coupling made up of spring
plates slightly different in form from that shown in Figures 12, 13, & 14, as shown
in the sectional view, Figure 16, which is a section through Figure 15, on the
line 16, 16 thereof.
Figure 17 is a view in elevation of the flexible shafting or coupling, made up of
another form of spring plates, which, in this instance, is shown as composed of thin
rings, as clearly shown in the sectional view Figure 18 which is a section through
Figure 17 on the line 18. 18. thereof.
Figure 19 is a view of the flexible shafting or coupling, still further modified in
that it consists of a tube having its walls cut through from opposite sides so as to
leave opposite connecting points, and these connecting points alternating and being
directly opposite for each successive spring plate formed by cutting the tube, see
Figure 20 which is a section through Figure 19 on the line 20, 20, thereof.
The part of my invention relating to the flexible driving shaft and the sheath
or cover thereof is designed, more especially, 'for use with dental engines where
it is desirable that short bends be made in the rotating shafting which drives
the operating tool in order to give wide scope and free range to said tool and
so that the point of the operating tool or drill, driven by the shafting may be
directed to places otherwise inaccessible but my improvements relating to the
shafting and its enveloping sheath or cover are not limited of course to their use
with dental engines as they may be used with other machines and in various
ways. For instance my improved flexible shaft or coupling, when made of the
proper size may be made to connect the shafting of machinery, so as to impart
motion to shafting which lie at an angle to the main driving shaft. In short

page_text: my improvements in flexible shafts and sleeves therefor are applicable to nearly
all machinery and all places where flexible coupling or universal joints may be
required. So also I desire it to be understood that the part of my invention.
relating to the hand piece may be used with different forms of flexible or other
shafting and various forms of enveloping sleeves or covers for such shafting other
than the improved forms of flexible shafting and sheath or cover shown by me.
A. A¹ represent two stiff sections of shafting joined together by my improved
flexible coupling or section of shafting. The stiff shaft sections A. A' are attached
respectively to discs or plates B. B¹ and these discs B. B¹ are connected together by
spring plates C, a series of which are employed. These spring plates C, are
parallel to each other, and are connected together by interposed washers or
separating pieces co by rivetting for example, so as to be held a short distance
apart, the first plate being connected to the second rigidly at two opposite
points c. c while the second plate is connected to the third also at two opposite
points, but these latter opposite points are at right angles to the connecting
points of the first and second plates, and thus the spring plates are rigidly con-
nected together at opposite points, and these opposite points alternate throughout
the series of plates, as clearly shown in the Drawings. The last spring plate is
rigidly connected to its disk B in the same manner as the first plate is connected to
the opposite disk B¹ whereby there results an exceedingly flexible joint between
the stiff sections A. A¹ of the shafting, which permits one section of said shafting
to be moved about at various angles in operation, relatively to the other section
without interfering with the rotating movement imparted from one shaft section to
the other. The flexible coupling is perfectly rigid as against rotatable or torsional
strain, while as stated, it permits one section of the shafting to be operated or
rotate at an angle relatively to the other. The spring plates C. which are rigidly
connected together as above described may be of various shapes. I have shown
several effective shapes in the drawing for instance in Figs. 1. 12. 13. and 14. The
flexible coupling or shaft section is made up of spring plates C having a central
portion with four radiating spring arms, two of which are united to the corre-
sponding arms of the plate on one side and the other two of which at right angles
to the first two, are rigidly connected to the corresponding arms of the plate on the
opposite side.
Figures 15 and 16 show substantially the same form of spring plate as is shown
in Figs. 1. 12. 13. and 14. but greater elasticity is given to the radiating arms
by reason of a central portion of less area or width than that of the plate shown
in Fig. 14.
In Figs. 17 and 18 the spring plates consist of thin flexible rings which are
rigidly connected together while held a short distance apart by riveting with small
interposed washers for example in the manner illustrated in connection with the
other plates. This form shown in Figs. 17 and 18 while giving greater strength
torsionally is not quite so elastic or flexible as the other forms described.
In Figs. 19 and 20 the same result substantially is attained as in the other
constructions of flexible coupling before described. In said figures the flexible
coupling is made of a metallic tube, the walls of which are alotted or cut through
so as to leave opposite connecting points between the rings thus formed and with
these connecting points arranged at right angles alternately as clearly shown.
In figure 20 a section of the slotted tube, Fig. 19 is shown which illustrates the
opposite connecting points between two adjacent rings formed by slotting a tube.
In the organization of the dental engine the shaft section A' may be extended
and have a bearing in the upper end or head of the usual foot power dental engine,
and be driven by a suitable pulley for example, while the front end of the shaft
section A has a connection with the rear or butt end of a chuck or tool holder of
the hand piece casing, so as to revolve said tool holder or chuck in bearings in said
casing when the flexible driving shaft is driven and thus revolve the operating tool
carried by said chuck or tool holder, the front end of the operating tool projecting
out in front of the band-piece casing to do its work.

page_text: In employing my improved flexible coupling or flexible shaft in the construction
of dental engines for example, I prefer to envelope the flexible shaft by a flexible
covering or sheath D, so that when the flexible shaft is being rotated in driving
the chuck or tool holder and the dental tool carried by the latter for instance,
there would be no danger of entanglement of the hair whiskers or clothing of the
patient, or of the operator, with the rotating shaft. To this end the stiff shaft
sections A, A¹ are mounted so as to turn or revolve in collars G. G¹ respectively
and said collars are connected together by a flexible tube E consisting of spirally
wound wire with the members of the spirals separated, as clearly shown in fig. 1,
and over this spiral wire tubing a covering F of flexible material preferably what
is known in the art as "kip" skin is tightly stretched whereby inasmuch as the
flexible coupling rotates within this cover or sheath, all danger of entanglement of
the hair or anything else with the rotating shaft is avoided. Said covering F is
preferably crimped between the coils of the wire tube E, as shown and the
collars G. G' have preferably cone surfaces f for the better securing and attachment
thereto of the ends of the said covering F.
The collar G' is preferably fitted with a thimble g¹ extending beyond the
reduced end g² of said collar so as to form a seat for an adjustable collar g
whereby the shaft section A' is secured from endwise movement in said collar G¹,
while fitted to rotate freely when driven by the rotating shaft section A', Figure 1,
on which, in the present example, the driving pulley of the engine may be mounted,
as is usual, instead of extending the shaft section A¹ in one piece for that purpose.
The collar G is preferably provided with a section G³ to a tubular extension g,
of which the rear section of the hand-piece casing H may be secured in any of
the usual well known ways. The main portion of the hand-piece H, as well as the
chuck or tool-holder I thereof, are not shown in Figure 1 of the drawing, as their
particular construction forms no part of the present invention, which is confined to
the improvements in the flexible shaft and sheath therefor, and to the manner of
connecting the rear end of a hand-piece casing and its chuck or tool-holder with
the front end of the shaft enveloping sheath or cover, and the front end of the
flexible shaft, respectively, by means of slip-joint or detachable connections which
permit the hand-piece, which includes the casing and chuck, to be readily detached
and applied as desired.
In Figure 6 the capability of the hand piece H to be turned at an angle to the
driving-shaft or sections A¹ A' is illustrated, and this is accomplished without
varying the length either of the flexible shaft or coupling, or of the flexible sleeve
or covering which envelops said shaft. When the hand-piece, in the manipulations
of the dentist, is turned or bent either to a greater or less extent in guiding or
directing the operating tool, the flexible shaft or coupling is contracted in length
or compacted on one side and expanded on the other, and this is due to the flexing
or bending of the spring plates making up the coupling; and a similar effect is
produced in the sheath or covering of said flexible coupling, by reason of the coils
or members of the spiral wire tube E being separated. The bending of the sleeve
contracts the members of the wire spiral on one side, and expands them on the
other, and, inasmuch as the covering F is flexible in the longitudinal line of the
shafting, it expands or is stretched at one side to accomodate the expansion of
the spiral tube.
In connecting stiff sections of shafting for general purposes in operative
machinery, where one section of the shaft is to be driven at an angle to the other
section, it may or may not be desirable to envelop the flexible coupling in a
covering or sheath. Where it is desirable to do so, the covering or sheath I have
described will be found very effective. In the example shown, particularly in
Figures 1, 6, 7, and 8 where I have shown my improvements in flexible shafts, and
in flexible sheaths or covers therefor, as adapted for use in dental engines, the
sheath or cover D for the flexible coupling is connected with the hand-piece H,
and in operation remains stationary while protecting the revolving shafts and
coupling within it, inasmuch as the handpiece of a dental engine is grasped by the

page_text: hand of the operator for the purpose of directing the revolving tool which is driven
by the rotating chuck of the hand-piece to do its work, the hand piece casing
remaining stationary in the hand.
It is to be understood that I do not limit myself to the details of construction of
the shaft, or to the particular metal or material of which the spring plates making
up the flexible coupling or shaft may be made as I believe myself to be the first
ever to have made a flexible shaft or a flexible coupling for stiff sections of shafting
made up of substantially parallel spring plates rigidly connected together, with the
capacity in said coupling or said shafting of affording a rigid rotating or torsional
driving connection, with the capability of flexing freely, so that one section of the
shafting may be operated at an angle to the other without interfering with the
driving power.
I will now describe my improvements in the manner of connecting the rear end
of the tool holder or chuck I and the rear end or section of the hand piece casing H
with the front end of the driving shaft and front end of the sheath or coupling
thereof, respectively, whereby one style of hand piece may be readily substituted
for another as before set forth.
The front end of the front shaft section A is fitted to turn in a bearing in the
front section G of the sleeve or cover D, by means preferably of a surrounding
sleeve A³ with which the shaft section A is rigidly connected by means of a
through pin a for example as shown in Figure 1 which through pin is shown as
passing through the plate or disc B, through the journal sleeve A³, and through
the stiff section A of the driving shaft uniting them all rigidly together, this
construction facilitating the fitting of the parts. The extreme front end of the
front stiff shaft section A of the driving shaft is fitted with a driving connection to
engage a driving connection i. of the rear end of the chuck or tool holder I of the
hand piece H. This chuck or tool holder I is fitted as usual as before stated to
rotate in a bearing or bearings in the hand piece casing, and without the capability
of endwise movement, so that while the chuck or tool-holder is free to revolve in
the hand piece casing, the two are connected together as far as endwise movement
is concerned, in operation. The driving-connection between the stiff shaft
section A, and the rear or butt end of the chuck or tool holder I consists preferably
of a tapered or bevelled end rib or projection of said chuck or tool-holder, which
fits a groove or seat between two forwardly projecting, and preferably tapered or
bevelled-end ribs or fingers a¹ a¹ on the front end of said shaft section a central
projection or pin a* also extends forward at the front end of the shaft Section A to
enter a socket i¹ in the rear end of the chuck or toolholder I and this projection or
pin a² is preferably split and thus provided with spring jaws, so that when the
driving connection is engaged between the front end of the shaft Section A and
the rear end of the chuck or toolhoolder I said projection enters the central opening
or socket in the rear end of said chuck or toolholder so as to form a steadying
connection between the chuck or toolholder and the driving shaft while the
engagement of the rib or projection i with either one of the ribs or projections a'
of the shaft A forms a rigid driving connection during the rotation of the driving
shaft. It will thus been seen that the driving connection between the front end of
the driving shaft and the rear end of the chuck or toolholder is a telescoping or
slip joint connection, and is made by moving the end of the chuck or toolholder
backwardly so as to engage its rigid rib with one of the rigid driving ribs or
fingers a¹ of the driving shaft and this engagement of the driving ribs or fingers
or the passage of the rib or finger i past the rib or finger a¹ is facilitated by the
tapered shape or beveled ends of the opposing ribs there being no danger by such a
construction of the driving ribs or fingers coming in contact end to end and thus
preventing the formation of a driving connection.
The connection between the rear end or section h of the hand-piece casing H and
the front end g of the front section G of the sleeve D also consists of a slip joint or
telescoping connection by reason of the reduced front end g of said sleeve section G
entering the rear end or rear section of the hand piece casing as clearly shown in

page_text: Figures 1. 8. 9. 10 and 11. When the rear end of the tubular hand-piece casing is
slipped upon the front end of the sleeve section G it is held thereon by the engage-
ment of the front shouldered or hooked end j of a spring latch J. which engages an
annular groove ¹ formed upon the interior surface of the rear end or rear section
of said hand-piece casing-Said latch J is fitted by a projection ; in a socket g³ in
the sleeve section G and is acted upon by a spring, the tendency of which, as
clearly shown in Figure 1 is to hold the front or hooked end j of the latch J. in
engagement with the annular groove h¹ of the rear section of the hand-piece
casing. Said hand-piece casing by means of the latch J is therefore not only
locked upon the shaft sleeve from endwise movement but in addition is free to
swivel or turn axially by reason of the annular groove h¹ to conform to the turning
movement of the hand of the operator when manipulating the Engine.
From the above description of the connections between the front end of the
driving shaft and rear end of the chuck or tool holder and front end of a shaft
enveloping sheath and rear end of the hand piece casing, it will be obvious that all
that it is necessary to do, to detach the hand piece casing and the chuch or tool
holder carried thereby from the driving shaft and the enveloping sleeve is to
depress the spring latch to release it from its hold in the annular groove h¹ of the
hand piece casing whereby said casing and chuck may be drawn off endwise and
detached when they may be again readily inserted in place and a firm driving
connection insured by the fitting of the parts together, as before described.
If it is desired to use in place of the usual straight hand-piece in which the tool
projects out forward in the axial line of the hand-piece a hand-piece in which a
tool is driven at an angle to the longitudinal line of said hand-piece, the first or
usual hand-piece may be readily detached and an angle hand-piece having corre-
sponding connections at its rear end be substituted in its place and this may be
readily accomplished as the work of the Dentist requires it as will be obvious and
as shewn in Figures 1. 6 and 7.
Instead of the latch connection J above described between the hand piece casing
and the shaft enveloping sheath or cover, the connection may be made in various
ways without departing from my Invention-For instance the connection may be
by sectional screw ribs as shown in Figures 8. 9. 10 and 11. In those Figures
there are sectional screw or cam ribs on the interior of the hand piece casing,
which may be slipped past corresponding external ribs on the front section G of
the sleeve or cover, and then turned to engage the ribs or cams so as to prevent the
accidental withdrawal of the hand piece from the front end of said sleeve.
It will be obvious from what has been said that in fitting the rear end of the
hand-piece casing upon the front end of the shaft enveloping sleeve that the rear
end of the chuck or tool holder will at the same time be engaged with the front
end of the driving shaft so as to form a driving connection between the two and
upon then turning the hand-piece casing to engage its ribs with those of the front
sleeve section, the parts will be locked in position for operation.
Other forms of slip joint or telescoping driving connections permitting of the
ready separation and connection of the parts may also be employed between the
front end of the driving shaft and the rear end of the chuck or tool holder.
I believe myself to be the first ever to have provided a hand-piece with a sliding
or readily detachable connection between the hand piece casing and its chuck
or tool holder and the shaft enveloping sleeve and driving shaft respectively and
this part of my Invention is therefore, not limited to the particular details of
construction illustrated and described herein.
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. The combination of the driving shaft with the chuck or tool holder by means
of a slip joint or telescoping driving connection consisting of rigid tapered or
bevelled end driving ribe or fingers onhotantialle.

page_text: 2.-The combination of the driving shaft with the chuck or tool holder by means
of a slip joint or telescoping driving connection consisting of rigid driving ribs or
fingers projecting from the chuck or tool holder, and the driving shaft respectively
and the central socket and pin guiding and steadying connection substantially as
described.
3. The combination of a hand-piece casing with a supporting sleeve, by means of
a telescoping or slip joint connection and a sectional screw rib locking connection
substantially as described.
4. The combination with the enveloping sleeve and the driving shaft thereof, of
a hand piece casing and its chuck or tool holder carried thereby by means of
detachable telescoping or slip joint connections substantially as described.
5. A flexible shaft or coupling consisting of a series of substantially parallel
spring plates rigidly connected together substantially as described.
6. A flexible shaft consisting of stiff sections connected together by a coupling
consisting of substantially parallel spring plates rigidly connected together at
opposite points and these points alternating so as to be at right angles, or sub-
stantially at right angles, to each other throughout the series of plates substantially
as described.
7. In combination with a flexible shaft a flexible sheath or cover consisting of
a tube of spirally wound wire, the spirals or members of which are separated so
that the tube may be bent without affecting its length and of a covering of elastic
material crimped between the coils of the wire substantially as described.
8. The improvements in flexible shafting and appliances in connection there-
with substantially as described and represented by the annexed drawings.
Dated this 29th der of Santamber 100K