Year: 1887

page_text: 1, JOHN SMALLEY CAMPBELL, dentist, of 20 rue des Pyramides, Paris, France,
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:-
My improved dental engine has been devised mainly for the purpose of affording
every facility of direction of the hand-piece to the operator. Substantially speaking,
my dental engine is composed of a horizontal hollow bracket swivelling on a fixed
stand and receiving internally a slide, the outer end of which carries a vertical slide,
carrying, at its top end, the usual belt pulley connected to the driving spring, dental
tool and hand piece. Both slide pieces can be adjusted and set by means of
screws.
Driving motion is imparted to the dental tool by an endless belt passing over a
driving pulley set in motion by hand or foot power or by motive power, and over
intermediate pullies. Whenever the two slides are displaced and adjusted, the slack
of the endless driving belt is taken up by a spring or by a weight.
In the accompanying drawings,
Fig. 1 sheet 1 is an elevation and fig. 2 sheet 1 a plan of the dental engine.
Fig. 3, 4 sheet 2 and 5 sheet 3 show the same engine, together with its driving
mechanism, in different positions.
Fig. 6, 7 sheet 1 are details.
1 is a stand secured to a wall or otherwise and capable of receiving a loose
bracket 2, reinforced by a support 3. 4 is a collar forsetting the bracket 2 in any
required height. The bracket 2 is hollow for receiving a slide 5 which can be set by
a screw 6. The outer end of the slide is formed with a vertical hollow piece 7 for
receiving a vertical slide 8 which can be set by a screw 9. The top portion of the
vertical slide 8 is formed in the usual manner and carries a pulley 10, the axis of
which is connected by a usual spring or an equivalent device to the dental-tool held
in the usual hand-piece 11, fig. 1 & 2.
The rotary motion for the dental tool contained in the hand-piece 11 is derived

page_text: from a driving pulley 12 fig. 3 & 4 conveying an endless belt 13 over pullies 14, 14,
15, 15, 16, 16 to the pulley 10. The pair of pullies 15, 15 and 16, 16 are held
respectively in adjustable frames 18 which can be set by means of screws 19.
20 is a weight and 21 a rope or chain passing over pullies 22, 22, for putting a
constant tension on the driving belt 13.
In fig. 4, the horizontal slide 5 is brought out and the vertical slide 8 is raised up ;
the position of the driving belt 18 is modified accordingly, and the weight 20 has
been likewise displaced, but the tension of the belt 13 remains the same.
In fig. 5, the endless belt 13 passes directly from the pullies 14, 14, to the pullies
16, 16, avoiding the pullies 15, 15. This modification may be introduced if desired ;
the arrangement of the weight 20 remains the same.
23 is the
Fig. 6 & 7 are detail views of the pullies 14, 14 shown in fig. 3, 4 & 5.
frame provided at the top with an eye 24 for connecting the device to the rope 21 and
provided centrally with an axis, not shown, upon which are slipped the two pullies 14
& 14 and secured by screws 25, 25. 26, 26 are side pieces held by the screws 25, 25
and by a cross-piece 27 cast with the frame 23.
This device offers every facility for putting the belt 13 on and off, without taking
any piece apart.
Having now particularly described & ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
First. The hereinbefore described dental engine characterised by the following
main parts:
a) A bracket 2 loose on a stand 1.
b) A collar 4 with a set screw, for adjusting the bracket at any desired height.
A slide 5 capable of adjustment by a set screw 6.
d) A vertical slide 8 capablo of adjustment by a set screw 9.
Pullies 14, 14, 15, 15, 16, 16 & 10 and endless belt 13.
Adjustable pulley frames 18, 18.
Second. The construction of pulley frame 23 with cross-bar 27 eye 24 and side
pieces 26 with pullies 14, 14 and screws 25, for the purpose described and as illustrated
in fig. 6 and 7.
Third. The means of putting a constant tension of the driving belt 13 of a dental
engine, comprising a weight or spring or equivalent device 20, a rope or chain 21
passing over pullies 22, 22 and a set of two pullies 14, 14 secured to the opposite end
of the rope 21, as stated with reference to fig. 3 4 & 5.
Dated this 20th day of February 1887.