Improvements in Holders, especially applicable to Dental Drills.
Year: 1893

page_text: Date of Application, 4th Nov., 1893
Complete Specification Left, 3rd Aug., 1894--Accepted, 8th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements in Holders, especially applicable to Dental Drills.
We, HERBERT ARTHUR EDWARDS, Manager, and DUNCAN DEWAR HEPBURN,
Director, both of 6 to 10 Lexington Street, Golden Square, in the County of
Middlesex, do hereby declare the nature of this invention to be as follows :-
This invention relates to the class of instrument in which the tool is held in a
split tubular chuck received in a rotating sleeve. In such holders the chuck has
a cone at one end and a screw at the other. A nut upon the screw draws the
chuck into the sleeve and causes it by reason of the cone to grip the tool. It will
thus be seen that if the nut unscrews from any cause the tool becomes loose.
According to this invention this objection is overcome in the following manner:-
The inner end of the tool is wedge shaped, a notch being cut on one side of the
wedge to receive a pin projecting radially inwards from the chuck. A loose wedge
mounted on a slide on the outside of the chuck is also provided corresponding with
the wedge on the end of the tool the two together forming a cylinder fitting the
inside of the chuck the notch becoming a radial hole in this cylinder. So long
therefore as this wedge remains in place the tool cannot be withdrawn for it is in
fact pinned to the chuck but when the wedge is removed a slight turn of the tool
frees the pin from the notch.
Dated this 2nd day of November 1893.
HERBERT A. EDWARDS.
DUNCAN D. HEPBURN.
COMPLETE
SPECIFICATION.
Improvements in Holders, especially applicable to Dental Drills.
We, HERBERT ARTHUR EDWARDS, Manager, and DUNCAN DEWAR HEPBURN,
Director, both of 6 to 10 Lexington Street, Golden Square, in the County of
Middlesex, 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 the class of instrument in which the tool is held in a
split tubular chuck received in a rotating sleeve. In such holders the chuck has a
cone at one end and a screw at the other. A nut upon the screw draws the chuck
into the sleeve and causes it by reason of the cone to grip the tool. It will thus be
seen that if the nut unscrews from any cause the tool becomes loose.
According to this invention this objection is overcome in the following manner :-
The inner end of the tool is wedge shaped, a notch being cut on one side of the
wedge to receive a pin projecting radially inwards from the chuck. A loose wedge
mounted on a slide on the outside of the chuck is also provided corresponding with
the wedge on the end of the tool the two together forming a cylinder fitting the
inside of the chuck the notch becoming a radial hole in this cylinder. So long
therefore as this wedge remains in place the tool cannot be withdrawn for it is in
fact pinned to the chuck but when the wedge is removed a slight turn of the tool
frees the pin from the notch.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of the chuck and
Figures 2 and 3 are a side elevation and plan respectively of the tool.
Figures 4, 5 and 6 are a side elevation, an underside view and a plau respectively
of the loose wedge and slide.
Figure 7 is a longitudinal vertical section and Figure 8 a transverse section (on
the line 8-8 Figure 7) of the chuck with the tool and wedge in place in it.
a is the split chuck, is the tool and b¹ the notch in the wedge at its end. c is
the loose wedge fixed to the slide d and e is a screw pin fixed to the chuck a and
forming a guide for the slide d.
When the parts are in the positions shown at Figures. 7 and 8 the tool b cannot
be withdrawn from the chuck a being prevented by the pin e from moving
longitudinally and by the pin e aided by the wedge e from turning. If however the
wedge c be moved to the right of Figure 7 the tool & can be turned from left to
right of Figure 8 until the notch bin it is clear of the pin e and then it can be
withdrawn longitudinally. The parts b and c need not necessarily be wedge shaped
they might for example be semi-cylindrical.
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. The combination of the chuck, a pin or projection in the chuck, the tool end
so formed that it does not completely fill the chuck and having a notch or recess in
it to receive the pin or projection and a piece entering the chuck and fitting the end
of the tool substantially as described.
2. The means for holding tools substantially as described and shown in the
drawings.
Dated this 3rd day of August 1894.
HERBERT ARTHUR EDWARDS.
DUNCAN D. HEPBURN.