Year: 1887

page_text: Date of Application, 16th Aug., 1887
Specification Accepted, 23rd Sept., 1887.
I, SYDNEY PITT of Sutton in the County of Surrey, Gentleman, (a communication
to me from abroad by Frank Abbott of New York City, County and State, United
States of America, Dentist) 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 :-
The invention relates to improvements in dental pluggers of the type known as
"hand "pluggers (as distinguished from engine driven pluggers) in which the blows
of the sliding hammer are communicated to the plugger point by means of a spring
operated by the pressure of the plugger point upon the filling which is to receive the
blow, and which is to be impacted or condensed in the cavity of the tooth.
The object of the invention is to improve hand-pluggers by simplyfying their
construction, and improving the effectiveness of their operating organism.
To this end the invention consists of certain novel organizations of parts and
combination of devices which will first be described, with the aid of the accompanying
drawings, in detail, as embodied in the best way now known to me, and then particularly
recited in the claims at the close of this specification.
In said drawings
Figure 1 is a view in elevation of the improved plugger, about the usual size of
such instruments.
Figure 2 is a longitudinal section therethrough enlarged for the sake of clearer
illustration, and showing the parts in their normal position, or at rest.
Figure 3 is a view of the front end of the internal parts of the instrument, partly
in section, and showing the parts in the position they occupy in operating, with the
hammer raised and just prior to being tripped to deliver its blow upon the plugger
point or tool holder.
Figure 4 is a view substantially similar to that of Figure 3, with the sliding hammer
This view shows more
and tripping portion of the instrument shown in dotted lines.
clearly the blow-receiving collar and its hard-rubber or equivalent facing of the tool-
carrying shaft or spindle, and the spring which acts upon the hammer-raising

page_text: tripping lever carried by said spindle, and also the position of the parts just after the
lifting lever has been tripped and the hammer thrown forward to strike the blow-
receiving surface or end of said spindle collar.
Figure 5 is a view of a portion of the instrument, showing, more particularly, the
front section of the casing and the tripping case, the blow receiving collar and the
spindle being drawn back, and the front end of the handle or middle section of
the casing being shown detached and in section.
Figure 6 is a view of the tripping case detached, showing, more particularly, its
slotted side to accommodate movements of the tripping lever rocking therein.
Figure 7 is a view of the end of said tripping case showing slots or recesses therein
to receive the projecting ends of a pin which pivots the tripping lever in the spindle,
and which passes through the blow-receiving collar, said pin ends fitting said slots or
recesses of the tripping case to prevent the spindle from turning.
Figure 8 is a view in elevation of the encased hammer impelling or striking
spring.
Figure 9 is a view of the main portion of the rear casing section; and
Figure 10 is a view of the minor or other portion of said rear casing section,
showing its connection with a mail screw-tube which reciprocates a female screw-tube
or nut, to control the power of the hammer or striking spring to regulate the blow to
be struck.
Figure 11 is a perspective view of the retaining plate coupling the two portions of
the rear casing section together, with the capacity of the minor or end portion to turn
relatively to the other portion, in regulating the power of the impelling or striking
spring.
The casing of the instrument is preferably tubular, and made in three main sections,
a front section A, a main or handle section A¹ and a rear section A A³. The front
section is or may be roughened, as at a, to afford a better grasp for the fingers of the
operator, and is screw-threaded, so as to screw into the front internally-threaded end
of the main section A'. The front end of the rear section A2 A3 is likewise threaded,
to screw into the rear internally-threaded end of said main section A. Said rear
section is made up of two portions A2 A³ the portion A³ fitting in the portion A2 by
means of a front sleeve A forming part of the portion A³ and said portion A³ having
an annular groove a¹ to receive the bent end a' of a plate A fastened on said portion A³
with its bent end a passing through a slot a' into said groove a¹. By this coupling of
the portions A A³ together, the portion A swivels or turns on the portion A³ so as
to revolve the sleeve A for a purpose which will hereafter appear. A central spindle B
passes through the casing from end to end, and its ends are screw threaded to receive
the threaded ends of the tools or plugger points b one for each end of the instrument,
as is common, so that thrust and pull blows can be delivered, and all character of
fillings reached.
Separate views of the tools are, also, shown in Figure 1, and they may, of course,
be secured in the tool holding spindle in other ways than by the screw-threaded ends.
The hammer C is fitted to the spindle B so as to be guided and slide freely thereon,
without frictional contact at its periphery. This permits easy action. The bore of
the hammer is preferably of smaller diameter at its ends than between them, so as to fit
the hammer to slide on the spindle by end bearings c c. This reduces the friction to
a minimum.
The hammer C is thrown forward by an impelling or striking spring D when the
hammer is moved back to compress said spring and is then released or tripped, in the
usual way. This spring, however, is peculiar. It has no frictional bearing at its
outer side against the interior of the casing, which is objectionable. On the contrary, it
is fitted with a covering such as leather, having frictional contact with the casing and
in which the spring may be compressed and expanded in action. This covering has
another function. It prevents noise from the spring, stopping vibration and making
the action of the spring noiseless. The front end of said striking spring D bears
against the rear end of the hammer, and its rear end against the front end of an
adjusting nut or thimble E. This adjusting nut is internally-threaded, and works on

page_text: male threads of the sleeve A* of the swivelling portion A' of the rear casing section.
The nut is held from turning by the front bent end at of the plate A' which passes
through a hole a in the casing section A* A³ into a longitudinal slot e of said
nut E.
Obviously, upon turning the sleeve A of the swivelling portion A³ of the rear
section of the casing, the nut E may be moved back and forth, to regulate the tension
or force of the striking spring D and, consequently, the force of the blows administered
by the hammer to the plugging point or tool.
The front end of the hammer is the striking end, and normally rests upon an
annular shoulder formed by the rear end of a sleeve F, which I term the tripping
case, see Figure 2. This tripping case is confined between a shoulder a' of the main
casing section A¹ and a shoulder or shoulders of the front casing-section A as, for
instance, at a³ and a' and is locked from turning by a lug or pin f which enters a
slot in the casing section A. See Figures 2 and 5. The spindle B passes through
this tripping case F and its front end is much reduced, so as to permit the rear end
of the case-raising spring G to be fitted thereon, and bear against the tripping case as
a shoulder. The front end of said case-raising spring bears against a shoulder formed
by a collar H pinned to the spindle B, the rear reduced end h of said collar H forming
a sleeve, and the space between the rear end of said sleeve and the front end of the
tripping case defines and limits the range of end-wise movement of the casing of the
instrument on the central spindle.
The case-raising spring G, like the hammer spring D, is fitted with a cover g such
as leather, and for the same purposes.
Within the tripping case the spindle B is slotted, as at 6 for example, to receive
a rocking hammer-raising and tripping lever or latch I pivoted by means of a through
pin i. The ends of said pin also pass through a blow-receiving collar J so as to unite
said collar firmly to the spindle B. This blow-receiving collar is fitted to work or
slide in the enlarged bore of the rear end of the tripping case F. One side of said
tripping case is slotted to permit of the passage of the tripping lever I and enable its
tail end to rock or vibrate therein.
A spring acts on the tail end of the tripping lever I with a tendency to throw
the rear or hammer end of said lever crosswise of the slot in the spindle in which it
is pivoted.
The lever I is peculiar. It has a curved end, the centre of the curve being the
axis of the lever. The end of the hammer against which this curved end of the
lever acts, is correspondingly curved, so that the rocking of the lever on its pivot
morely causes its end to rub over the curved surface of the hammer end, without, by
the rocking of the lever per se causing any elevation of the hammer, as a square or
flat surface would do. This lessens friction and conduces to regular smooth action.
The tail end of the tripping lever has a curved or cam surface to work against a
cam surface of the tripping case F.
The operation of the instrument is as follows:-The normal position of the parts is
as represented in Figure 2. Now place the point of the plugging tool on the filling to
be compacted. Press on the casing or push or pull according to which end of the
instrument is used. This causes the casing to slide on the spindle, and as the end of
the hammer-raising and tripping lever is in contact with the hammer forces the
hammer to slide on the spindle and compress its impelling spring. As the
pressure continues the cam surface on the tail end of the lever begins to work on
the cam surface of the tripping case, and it is rocked inwards, so as to carry both
ends of said lever within its slot in the spindle, and, of course, its hammer end out of
lifting contact with the hammer. At the end of the necessary movement, the lever is
entirely withdrawn from contact with the hammer, or is tripped and released, and at
this moment the striking-spring, with its accumulated, power, impels the hammer
quickly against the blow-receiving surface of the collar J, which during the movement
of the casing on the spindle, has been protruded or exposed, as in Figures 3 and 4,
beyond the end of the tripping case. The blows thus received on the collar J are
communicated to the tool or point through the spindle B.

page_text: The blow-receiving collar is, preferably, provided with a hard rubber collar J¹ to
deaden the sound of the blows administered by the hammer.
The advantages of the instrument are simplicity of construction and easy effective
operation.
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 casing, the hammer, the striking-spring of the hammer,
the slotted adjusting nut of said spring, the swivelling portion of the casing having
an annular groove, and the interlocking connection of the casing fitting said slotted
nut and annular groove substantially as described.
2. The combination of the casing, an inclosed expanding and contracting spring,
and a sound-destroying cover for said spring between it and said casing, substantially
as described.
3. The combination, in a dental plugger, of detachable casing sections fitted with an
internal detachable tripping case confined between shoulders of said detachable casing
sections, substantially as described.
4. The combination of the annular tripping case, the spindle, the hammer fitted to
slide on said spindle, and the pivoted hammer-raising and tripping-lever substantially
as described.
5. The combination of the casing, the slotted spindle, the hammer, the tripping
lever pivoted in the slot of said spindle and a cam surface in said casing to rock said
lever to release the hammer substantially as described.
6. The combination with the hammer having a curved seat on its striking end,
of a hammer-raising and tripping lever, having a curved lifting end to fit said curved
striking end of the hammer substantially as described.
Dated this 16th day of August 1887
CARPMAEL & Co.,
Agents for the Applicant