U.S. patent number 3,749,371 [Application Number 05/162,470] was granted by the patent office on 1973-07-31 for dental material mixer.
This patent grant is currently assigned to Dentsply International Inc.. Invention is credited to Richard P. Folkenroth, William G. Mader.
United States Patent |
3,749,371 |
Folkenroth , et al. |
July 31, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
DENTAL MATERIAL MIXER
Abstract
A mixer for dental material adapted to agitate such materials in
a conventional mixing capsule supported between the outer ends of a
pair of arms which are actuated to oscillate the capsule along a
closed path by an electric motor which drives a diagonal bushing
that causes oscillation of said arms.
Inventors: |
Folkenroth; Richard P. (York,
PA), Mader; William G. (York, PA) |
Assignee: |
Dentsply International Inc.
(York, PA)
|
Family
ID: |
22585754 |
Appl.
No.: |
05/162,470 |
Filed: |
July 14, 1971 |
Current U.S.
Class: |
366/209; 248/605;
366/602 |
Current CPC
Class: |
B01F
11/0028 (20130101); A61C 5/68 (20170201); B01F
15/00746 (20130101); Y10S 366/602 (20130101) |
Current International
Class: |
A61C
5/06 (20060101); A61C 5/00 (20060101); B01F
11/00 (20060101); B01F 15/00 (20060101); B01f
011/00 () |
Field of
Search: |
;259/DIG.20,72,75,91
;248/15,18,358R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Price; William I.
Assistant Examiner: Coe; Philip R.
Claims
We claim:
1. Apparatus for mixing different dental materials comprising in
combination:
a. A base adapted to be disposed upon a supporting surface,
b. frame means comprising brackets connected to and extending
upward from said base,
c. motor support means,
d. vibration absorbing means interconnected between said motor
support means and said brackets to minimize transmission of
vibrations therebetween,
e. a motor connected to said motor support means,
f. capsule supporting means,
g. drive means for said capsule supporting means connected thereto
and to said motor and operable to oscillate said capsule supporting
means, and
h. movement limiting mechanism including elastic means connected to
said drive means and operable to restrain the oscillating movement
of said capsule supporting means within predetermined limits.
2. The mixing apparatus according to claim 1 in which said brackets
are positioned adjacent opposite sides of said motor and said
vibration-absorbing means between said brackets and motor support
means being positioned substantially opposite the center of gravity
of said motor and drive means connected thereto.
3. The mixing apparatus according to claim 1 in which said motor
support means is a substantially U-shaped frame member having
opposite legs which are connected to said brackets by said
vibration-absorbing means.
4. The mixing apparatus according to claim 3 in which said U-shaped
frame member is connected to said motor by additional
vibration-absorbing means disposed between said frame member and
motor.
5. The mixing apparatus according to claim 4 in which the bight
portion of said U-shaped frame member is positioned above said legs
in the operative position of said apparatus and said motor is
connected to said frame member below said bight portion in
depending manner.
6. The mixing apparatus according to claim 5 further including a
stabilizing member depending from said motor and said apparatus
further including movement-absorbing means mounted between said
stabilizing member and said base to limit the vibration of said
motor relative to said base when said apparatus is operating
without appreciably transmitting such vibrations to said base.
7. The mixing apparatus according to claim 1 in which said motor
has a shaft projecting from one end thereof,
i. bushing means fixed to said shaft having an axis at an acute
angle to the axis of said shaft and extending rotatably through a
bearing in one end of said capsule supporting means,
j. and a plurality of elastic means supporting in opposition to
each other and engaging said one end of said capsule supporting
means at opposite sides thereof, whereby a nutational path of
movement of said other end of said capsule supporting means is
effected when said motor is energized and said path of movement is
elastically restrained within predetermined limits.
8. The mixing apparatus according to claim 7 in which the other end
of said capsule supporting means comprises a pair of arms
respectively engageable with opposite ends of a mixing capsule to
support the same with the axis of said capsule disposed generally
parallel to the axis of said motor.
9. The mixing apparatus according to claim 7 which further includes
a bracket having a pair of arms supported by said motor support
means and said arms extending toward said one end of said capsule
oscillating means, the outer ends of said arms being spaced
substantially equally at opposite sides of the axis of said motor,
and said elastic means comprising tension springs, the outer ends
of said arms respectively engaging one end of each of said springs
and the opposite ends of said springs being connected to opposite
sides of said one end of said capsule oscillating means.
10. The mixing apparatus according to claim 9 in which said one end
of said capsule supporting means is provided with a pair of ears
respectively projecting diametrically away from the axis of said
motor and said opposite ends of said springs being connected
respectively to said ears.
11. The mixing apparatus according to claim 9 in which said motor
support means is substantially U-shaped and the bight portion
thereof being supported by said brackets of said frame means and
adapted to permit limited pivotal movement of the arms of said
motor support means about an axis extending transversely between
the arms of said motor support means.
12. The mixing apparatus according to claim 7 further including a
hub of substantial mass and weight fixed to said motor shaft and
rotatable therewith, said hub being adjacent said bushing means and
providing a flywheel effect.
13. The mixing apparatus according to claim 12 in which said
bushing is fixed directly to the outer end of said hub by a bolt
which is coaxial with the shaft of the motor and hub and is
threaded at the inner end thereof into said hub.
Description
CROSS-REFERENCE TO RELATED APPLICATION
The instant application covers the mechanical novelty of a dental
material mixer of which the aesthetic design aspects comprise the
subject matter of a design patent application filed on even date
herewith.
BACKGROUND OF THE INVENTION
In the practice of dentistry, it is essential that certain dental
materials be mixed to thoroughly blend the same in order to prepare
them for use in certain types of dental prosthesis. Typical
examples of dental materials of this type are dental cements,
cavity liners, non-metallic filling materials, and amalgams. The
individual ingredients which are mixed to produce a compound dental
material used in such dental prosthesis are maintained in separate
condition until such use is desired. Within certain periods of time
after the various types of materials are mixed, they harden or set
after application thereof to dental cavities and the like incident
to effecting such prosthesis.
It is conventional practice to mix such ingredients for said dental
materials of the aforementioned type within a small capsule into
which measured quantities of the various ingredients are
introduced. The capsules are then placed within certain well-known
types of mixing devices which provide a rapid oscillatory movement
of the capsule in order to thoroughly mix the dental ingredients
and materials. Under some circumstances, it is conventional to
introduce a small weighted member, known as a pestle, within the
capsule in order to enhance the mixing of the materials.
Typical examples of the mixing devices commonly used heretofore and
at present are illustrated in U.S. Pat. Nos. 2,286,599, dated June
16, 1942; 3,222,037, dated Dec. 7, 1965; and 3,411,755, dated Nov.
19, 1968. A more recent and also more sophisticated type of dental
amalgam-preparing apparatus comprises the subject matter of U.S.
Pat. No. 3,533,601, dated Oct. 13, 1970. Said structure includes
means for discharging measured quantities of desired ingredients
from reservoirs which are included with the apparatus into an
oscillating member having a mixing compartment in which the
ingredients are blended into an amalgam.
One of the principal difficulties resulting from operation of
mixing devices such as those illustrated in said patents is that
very objectionable noise is produced by the vibration of the
machine. The noise is somewhat in the nature of a penetrating-type
hum due to the imbalance of the vibrating means which supports the
capsules or equivalent mixing chambers. In addition, said prior
devices occupy a substantial amount of space in a dental
operatory.
SUMMARY OF THE INVENTION
It is the principal object of the present invention to provide a
dental material mixer which minimizes the vibration of the
oscillatory means by which the materials are mixed when enclosed
within a conventional capsule by insulating various essential parts
of the mixer from each other in a manner which transmits a minimum
amount of vibration to the base of the machine, and
correspondingly, to any supporting surface upon which the machine
is positioned in a dental operatory or otherwise, such minimizing
of vibration similarly minimizing the resulting noise produced by
the machine when operating.
It is another object of the invention to introduce a certain amount
of equilibrium into the means in the apparatus which restrain the
oscillating elements of the mixer to operation within predetermined
limits and thereby minimize wear upon the driving mechanism for the
oscillating members, as well as permit the motor to initiate
operation under a balanced load rather than an unbalanced load as
is customary in substantially all of currently used mixers of the
type to which the present invention pertains.
It is a further object of the invention to eliminate all rigid
connections between the oscillating elements of the mixer and the
base and enclosing housing thereof through the employment of a
plurality of vibration-absorbing members in the various connections
between certain elements and devices of the mixer, rubber grommets
of suitable elastic property, without restriction thereto, being
the preferred form of vibration-insulating means employed in the
mixer.
Details of the foregoing objects and of the invention, as well as
other objects thereof, are set forth in the following specification
and illustrated in the accompanying drawings comprising a part
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of a dental material mixer embodying
the principles of the present invention, part of the casing broken
away to illustrate certain details thereof.
FIG. 2 is a side elevation of the mixer shown in FIG. 1 as viewed
from the right-hand side thereof, part of the casing being broken
away to expose details of some of the operating mechanism with
greater clarity.
FIG. 3 is a top plan view of the mixer shown in FIGS. 1 and 2 with
part of the casing being broken away to expose details of the
operating mechanism in the mixer.
FIG. 4 is a side elevation of the operating mechanism of the mixer
which is exposed in FIG. 3, part of the illustration in FIG. 4
being shown in section, and the housing being removed to simplify
the view.
FIG. 5 is an enlarged fragmentary vertical elevation of part of the
driving mechanism for the oscillatory portion of the mixer
illustrated in the preceding figures.
FIG. 6 is a detailed plan view of part of the vibration damping
means included in the operating mechanism as seen on the line 6--6
of FIG. 4.
FIG. 7 is a fragmentary diagrammatic view illustrating the path of
movement described by the capsule-supporting portion of the
oscillatory mechanism of the mixer which is produced by a
diagonally extending bushing on the drive shaft of the motor which
is illustrated in FIG. 5.
FIG. 8 is a vertical sectional elevation of one example of
vibration-absorbing means employed between two elements of the
mixer as viewed on the line 8--8 of FIG. 3, said elements being
illustrated in phantom.
FIG. 9 is a perspective diagrammatic view showing in full lines the
various vibration-absorbing means and movement restraining elements
employed in the mixer, the elements with which said
vibration-absorbing and movement restraining means are associated
being illustrated in phantom in order to simplify the view and
otherwise to orient the relationship between said various means in
a concise manner.
DETAILED DESCRIPTION
Referring to FIGS. 1 and 2, it will be seen that the mixer
comprising the present invention includes a casing or housing 10
which may be made by molding or casting from any suitable material,
such as metal, synthetic resin, or otherwise. The base 16 is
provided with a sloping front panel 12 upon which suitable control
knobs 14 and 15 are mounted. A preferably planar base 16 also is
provided which may be made preferably from rigid material, such as
sheet metal. Said base also preferably is provided with resilient
feet or knobs 18, one example of which may comprise rubber
buttons.
The supporting elements 18 are adapted to rest upon a suitable
supporting surface 20, such as a counter in a dental operatory, the
top of a suitable cabinet, or even the bottom of a drawer within
which the mixer may be positioned and readily concealed when not in
use. To adapt the same to storage within a drawer, for example, it
will be seen, especially from FIGS. 1 and 2, that the vertical
profile of the machine is relatively low and the mechanism enclosed
therein has been suitably proportioned and arranged to make such
low profile possible. The base 16 may be secured, for example, to
the molded casing 10 by any simple, suitable means, such as
relatively long screw 22 which is threaded into an appropriate boss
24 formed in the casing 10.
The operating mechanism of the mixer comprising the invention
includes an electric motor 26 of suitable horsepower. Frame means
28 comprising a plurality of interrelated elements supports the
motor 26 relative to the base 16. Said frame means 28 comprise a
similar pair of vertical brackets 30 which may be formed from sheet
metal, for example, and are provided with horizontal feet 32 which
are suitably fixed to the base 16 by any appropriate means, such as
rivets, screws, or otherwise.
The frame means also include a U-shaped member 34, which also may
be formed from sheet metal. As best seen from FIG. 2, the member 34
is mounted with the horizontal bight portion 36 uppermost, whereby
the legs of the member 34 depend downwardly therefrom. The member
34 is of limited width, as best seen from FIG. 3, and an extension
plate 38 projects essentially horizontally in one direction from
the under surface of the bight portion 36 of U-shaped frame member
34, the plate being affixed thereto by spot-welding, rivets or
otherwise, not shown.
As indicated above, one of the principal objectives of the present
invention is to minimize the transmission of vibration, in
particular to the base 16 and supporting surface on which it rests
from the motor 26 and certain driving mechanism connected thereto
and actuated thereby, which is described in detail hereinafter.
Minimum vibration also produces minimum noise resulting from
operation of the mixer, and the latter especially is a further
objective of the invention. To this end, it will be seen that the
downwardly extending legs of the U-shaped bracket 34 are connected
to the upstanding brackets 30 by vibration-absorbing means or units
40, details of which are best shown in FIG. 8.
It will be seen that said vibration-absorbing means in the specific
illustration shown in FIG. 8 and certain of the other figures,
preferably comprise a grommet 42, formed from rubber or rubber-like
material, the periphery of which is provided with an angular groove
which receives the perimeter defining a hole 44 formed in each of
the depending side legs of the U-shaped frame member 34. The
grommet 42 is formed with a central hole of suitable size to
receive the shank of a connecting screw 46 which is threaded into
complementary threads formed within the flanged tubular nuts 48,
industrially known as Tee Nuts, the flanged head preferably being
of a geometrical configuration, such as a hexagon, to permit the
use of a wrench therewith.
The upper end portion of each of the brackets 30 also is provided
with a suitable hole through which the shank of screw 46 extends.
The head 50 of the screw engages the outer surface of bracket 30
and secures the same against one face of the grommet 42, while the
head of the tubular nut 48 engages the opposite face of grommet 42
and thereby secures the legs of the U-shaped framed member 34
respectively to the brackets 30 in a manner which will minimize the
transmission of vibration from the member 34 to the brackets and,
correspondingly, to the base 16 and casing 10 of the mixer.
To further augment the vibration-absorbing effect afforded by the
grommet 42, it will be noted especially from FIGS. 3 and 4 that the
motor 26 has one end of its shaft 52 projecting outwardly beyond
the bracket 30 and U-shaped frame member 34 for purposes of
supporting and actuating capsule supporting and oscillating means
54. Considering the motor and said capsule supporting and
oscillating means 54 as a unit, which they actually comprise, it
can be observed from FIGS. 3 and 4 that the centers of the several
vibration-absorbing means 40 are substantially in line with the
center of gravity of the combined motor 26 and capsule supporting
and oscillating means 54, which is the theoretic no-motion
location, thereby further contributing substantially to
minimization of transmission of vibration from said combined
mechanism to the base 16 and/or casing 10, as well as any
supporting surface 20, upon which the mixer rests for support.
To further contribute to the insulation of vibration from said
motor and capsule supporting and oscillating means to the base 16
and casing 10, attention is directed to FIGS. 3, 4 and 9, wherein
it will be seen that the bight portion 36 of the member 34 and
extension plate 38 support additional vibration-absorbing units 56,
which, for simplicity, preferably are similar to the
vibration-absorbing means 40, described hereinabove and also
illustrated in said figures, as well as FIG. 8. Referring
particularly to FIG. 4, it will be seen that the
vvibration-absorbing units 56 comprise grommets 58 which are
similar to the grommets 42. The angular grooves in the grommets 58
receive the perimeters which define holds 60 which are formed in
extension plate 38.
Flanged, tubular nuts 62, similar to nuts 48, extend through
central holes in grommets 58 to receive clamping bolts 64 which are
threaded into suitable sockets formed in the upper end of the
housing of motor 26, as is clearly evident from FIG. 4. Such
arrangement very largely insulates from the frame means 28
vibrations which are generated by the motor 26 and the capsule
supporting and oscillating means 54 which are directly connected
thereto. Thus, it will be seen further that the vibration-absorbing
units 56 supplement and cooperate with the vibration-absorbing
means 40, described above, to minimize the transmission of
vibrations directly to the base 16 of the mixer unit.
The shaft 52 supports and drives a relatively heavy hub 66 which is
of such size that it functions to an effective extent as a
flywheel. As seen from FIG. 4, a flat 68 is formed in shaft 52 and
the inner end of a setscrew 70 or similar locking member engages
said flat 68 to effect locking of the shaft 52 and hub 66 against
relative rotation, as well as against relative longitudinal,
separative movement.
Referring to FIG. 5, it will be seen that hub 66 is centrally bored
inward from its outer end to receive a bolt 72 by means of which an
oscillation-producing bushing or driving member 74 is tightly
clamped to the hub 66 for rotation therewith. The bushing 74 has a
central bearing portion 75 which is cylindrical and the bushing is
bored diagonally to the axis of said central portion so that the
axis of the bore is at a very acute angle to the axis of said
central bearing portion and bolt 72, as well as the axis of the
motor 26.
The inner races of a pair of similar anti-friction bearings 76 are
mounted upon the central portion 75 of bushing 74 and are suitably
fitted so as to be rotatable therewith. The outer races of the
bearings 76 are received within a complementary cylindrical opening
78 which is formed in oscillatory arm 80. The lower end of said arm
is slotted at 82, as shown in FIG. 2, and a clamping bolt 84
extends through suitable holes in the projecting lower end portions
of the slotted end of arm 80 in order to tighten said opening 78 of
arm against the outer races of bearing 76.
The arm 80 also is provided at diametrically opposite sides of the
intermediate portion thereof with pairs of similar ears 86, which
are best shown in FIGS. 2 and 3. Pins or bolts 88 extend
perpendicularly through said ears in parallel manner with respect
to the axis of opening 78 in the arm 80, for purposes to be
described hereinafter.
Oscillatory movement of the arm 80 is restrained to operation
within a predetermined limit by means of a bracket 90 which may be
formed from wire or rod stock, for example. The shape of said
bracket is best seen from FIGS. 2-4. The bracket is somewhat
U-shaped and has a bight portion 92 which is supported in a pair of
simple bearing members 94 which are suitably connected to the bight
portion 36 of frame member 34 which is nearest the hub 66 by any
suitable means, such as bolts 96, to provide limited pivotal
movement of the bracket relative to frame member 34, by which it is
supported. The side arms or legs 98 of bracket 90 preferably form
obtuse angles with the bight portion 92 of the bracket, so that it
will be seen that the shape of the bracket is not exactly U-shaped,
but only generally so. For purposes of ready designation, however,
bracket 90 is considered to be substantially U-shaped in this
description, as well as the appended claims.
The arms 98 terminate in notch-forming ends 100 for purposes of
loops on the outer ends of tension springs 102 being disposed
within the bases of said notches, while the opposite ends of the
springs have loops through which the pins or bolts 88 extend. It
will be seen that such an arrangement produces an equilibrium
condition with respect to the oscillatory arm 80 upon the central
portion 75 of bushing 74, in such manner that the energizing of the
motor may occur under a balanced load condition rather than an
unbalanced load situation as is that in dental mixing devices
presently used, examples of which are illustrated in said
aforementioned patents. Such balanced feature is considered to be
one of the novel and meritorious features of the present
invention.
The oscillatory arm 80 of the capsule supporting and oscillating
means 54 supports a pair of arms or legs 104, one end of each of
which are disposed within suitable shallow grooves, not shown,
which are formed in opposite faces of the upper portion of the arm
80. The upper portions of the arms 104 are provided with oppositely
extending recessed means 106 within which the opposite ends of a
mixing capsule 108 may be securely mounted for oscillatory movement
of the capsule by the means 54. Firm lodging and retention of the
opposite ends of capsule 108 within the recessed means 106 is
assured by the provision of a plurality of relatively strong leaf
springs 110, which bear against the mid portions of the outer sides
of arms 104 and the overlying end portions of said springs and arms
are effectively secured to the upper end of oscillatory arm 80 by
means of bolts 112.
OPERATION
The motor 26 is energized by means of current supplied through
power conduit 114 which is connected to a starting switch that is
operable by button 115, which is associated with control knob 15
that operates a timer unit 116, shown in FIG. 2. Suitable
circuitry, not shown, also connects an adjustable speed control
unit 117 of commercial type in the circuit between the starting
switch and the motor 26, said speed control unit being adjusted and
actuated by knob 14. In view of the fact that circuitry of this
type is of conventional nature, detailed description thereof is
believed to be unnecessary.
When the motor 26 has been energized by means of the aforementioned
button 115 of the starting switch and the time period of operation
has been selected by disposing timer knob 15 where desired, the
oscillatory unit 54 which supports the capsule 108 is oscillated at
a speed determined by the setting of the speed control unit 117
which is operated by knob 14. Different types of dental products
require different optimum time periods and speeds of oscillation to
effect the thorough mixing of the ingredients thereof. Certain
cements, for example, must be mixed quickly and used quickly before
final setting occurs, whereas the mixing of metallic amalgams
require longer periods of time and at different speeds from those
required for mixing cements.
Referring to FIG. 7, a diagrammatic illustration is included in the
form of a path outline 118, defined by successive arrows, which is
generated by the oscillatory means 54 upon the capsule 108. It will
be seen that the path is somewhat in the nature of a figure eight.
If viewed axially of the motor 26, however, the path is somewhat
arcuate, generally about the axis of bolt 72. Such a movement of
the capsule has been found to effect highly desirable results in
the mixing of substantially all types of dental material which
require such mixing. The path or orbit within which the capsule 108
moves may be considered to be a nutation, and correspondingly, the
oscillatory means 54 can be termed a nutation assembly.
In considering the nutational orbit or path of movement of the
capsule 108, it can be appreciated that such movement, particularly
at the upper end of an arm of reasonable length which is composed
of oscillatory arm 80 and the pair of arms 104 which are secured
thereto, very substantial vibration is imposed upon the motor 26,
the shaft 52 of which comprises substantially the main support of
the oscillatory means 54. In view of the purposely provided mass
and weight of the hub 66, however, which is directly rotated by the
motor shaft, a certain amount of gyroscopic effect is produced
which tends to minimize vibration of the motor. Also, the
cooperating pairs of vibration-absorbing means of units 40 and 56
additionally and substantially insulate the base 16 from receiving
such vibrations imposed upon the motor 26. Further, the mounting of
vibration-absorbing units 40 opposite the center of gravity of the
motor and oscillating means 54 thereon, as well as the provision of
the equilibrium condition which the springs 102 and their
supporting means tend to produce with respect to the support of the
oscillatory arm 80 upon the motor shaft, also tend to minimize the
vibration imparted to the motor, as distinguished from the result
of using only a single movement-restraining spring connected to the
oscillatory arm and the lack of any vibration-absorbing means, as
is conventional in dental mixing devices presently in use.
A further means tending to insulate movement of the motor 26 and
means 54 from being transmitted to the base 16 is provided in the
form of a pin having a threaded nut thereon or a bolt 120 which is
connected to the lower portion of the motor 26, near the rear end
thereof, as best shown in FIG. 4. A rigid disc-like supporting
member 122 is secured by rivets 124 or the like, see FIGS. 4 and 6,
to the rim portion of a large hole formed in base 16. The
supporting member 122 also is provided with a large hole within
which a rubber grommet is mounted. The periphery of the grommet is
grooved to receive the perimeter of said large hole formed in
member 122 and the center of the grommet is provided with a
perpendicularly extending hole which preferably contains a
thin-walled metal sleeve 128 through which the pin or bolt 120
extends. The material from which the rubber grommet 126 is formed
is preferably quite pliable so as to minimize the transmission of
vibratory movement of the motor to base 16.
The grommets 42 of vibration-absorbing units 40 and grommets 58 of
vibration-absorbing units 56 preferably are formed from rubber
compounds having a Shore A durometer number between approximately
50 and 75, the optimum number being approximately 70. The grommet
126 attached to member 122 also has similar characteristics. Said
grommets may also all be formed from synthetic resins suitably
formulated to provide equivalent physical characteristics, within
the spirit and purview of the present invention.
Without restriction thereto, the mixing device comprising the
present invention is capable of operating within a speed range, for
example, of between approximately 2,500 and 7,000 r.p.m. Such a
range affords a wide latitude which is highly useful to adapt the
mixer to accommodating substantially all types of dental materials
which require mixing through vibration within capsules and similar
mechanisms.
From the foregoing, it will be seen that the present invention
provides a dental mixer which is capable of a wide range of speeds
which, in conventional mixers, tend to produce substantial and
objectionable vibration which produces irritating and highly
objectionable noise in a dental operatory. The noise is of a type
which is very penetrating and actually is a loud irritating hum of
substantial magnitude. By minimizing the transmission of such noise
between the elements of the mixer which produce the same and the
base of the mixer which supports the mechanism, the resulting
vibration which is imparted to the base and casing of the mixer is
tremendously minimized and reduced over that which is found in
conventional dental mixers.
Such minimizing of the vibration upon the base of the mixer and,
correspondingly, upon any surface which supports the same, is
effected by the utilization of appropriate vibration-absorbing
means at critical locations, certain of which are adjacent the
center of gravity of the motor and oscillatory unit operated
thereby. The use of a heavy hub, in conjunction with the rotor of
the motor, serves in the capacity of a flywheel and produces a
certain amount of gyroscopic effect which also contributes to the
desired results of reducing or minimizing vibration and noise.
Still further, the equilibrium provided by using a pair of
movement-restricting springs which are connected to opposite sides
of the capsule supporting an oscillating means contributes to the
desired effect, as well as increasing the life of the driving
mechanism.
While the invention has been described and illustrated in its
several preferred embodiments, it should be understood that the
invention is not to be limited to the precise details herein
illustrated and described since the same may be carried out in
other ways falling within the scope of the invention as illustrated
and described.
* * * * *