close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2271809

код для вставки
Feb. 3, 1942.
2,271,809
F. W. THOMPSON
LABORATORY BALANCE
Filed Feb. .3, 1941
2 Sheets-Sheet 1
INVENTOR.
5750 M i/cwpso/v;
BY
|
ATTORNEY.
Feb. 3, 1942.
F, w. THOMPSON
LABORIATORY BALANCE
2,271,809
Filed Feb. 3, 1941
2 Sheets-Sheet 2
.him,
32H"I,
5 mm
__.._\
_____._
\mx
1,w\\\
m‘\1
w
_
BY
_INVENTOR.
f/a’lsp M 7/710MP50/Y.
%:TfoR/v£y.
Patented Feb. 3, 1942
2,271,809
UNITED STATES " PATENT OFFlCE'
2,271,809
LABORATORY BALANCE
Fred W. Thompson, Denver, Colo.
Application February 3, 1941, Serial No. 377,156
’
7 Claims.
(Cl. 265-54)
This invention relates to an analytical or labo
have any standard construction. Typical stand
ratory balance. The usual analytical balance is
ard parts of a balance are designated by numerals
on the drawings as follows: beam l0, pans ll,
provided with a hollow shaft or pedestal rising
from the ?oor within the balance case for sup
pan bails I2, stirrups l3, knife edges [4, bearing
posts l5, pivot studs l6, beam lifting yokes ll,
rider shifting rod l8, agate bearings 30, plumb
line 33, plumb indicating point 34, leveling legs
35, pointer 51, and indicating scale 58.
porting the beam pivots and the beam lifting
mechanism.
The principal object of this invention is to
eliminate the post within the case and to support
the beam and all related apparatus directly from
The balance illustrated is enclosed in a glass
the back wall of the case, such a construction 10 case consisting of metal frame Hi, the sides of
which contain glass panes 20 and the front of
and to a much more economical and facile meth
which is closed by a liftable glass door enclosed
od of manufacture.
in a metallic door frame 2|. The top is covered
results in greater accessibility to the balance pans
Other objects of the invention are to provide
a laboratory balance in which all the operating .
mechanism for lifting the beam will be accessible
on the exterior of the case for repair, lubrication
by a metal top plate 22, and the bottom is closed
by means of a downwardly ?anged floor plate 23.
The back of the case, however, is closed by
two glass panes 55 which are separated vertically
at the middle of the case by means of a tapered
metallic supporting member 24 which extends as
a unit from a middle leg 25, which supports the
case at the rear, to the top plate 22. The member 24 is secured by means of cap screws 3| to
the rear ?ange of the floor plate 23. It is also
and adjustment; to provide guide bearings for
the beam lifting mechanism which can be quick
ly and easily machined without requiring micro
metric boring and turning operations, which will
be free from bearing looseness, and which can be
easily adjusted to take up any wear or looseness
which may occur in use.
provided with a plumb post 32 from which the
Other objects and advantages reside in the de— 25 plumb line and plumb 33 depend over the indicat
tail construction of the invention, which is de
ing point 34 on the ?oor.
signed for simplicity, economy, and efficiency.
On the front of the member 24, below the
These will become more apparent from the fol
beam H], a pyramidal boss 26 is formed extend
lowing description.
ing forwardly into the case. An angle bracket
In the following detailed description of the 30 21 is bolted to the boss 26 by means of suitable
invention reference is had to the accompanying
attachment bolts 28 and extends forwardly in the
drawings which form a part hereof. Like nu
case beneath the beam In. The two bearing posts
merals refer to like parts in all views of the draw‘
l5 are attached to this angle bracket by means of
ings and throughout the description.
suitable attachment screws 29 and ‘extend ?xedly
In the drawings:
35 upward therefrom in parallel relation, terminat
Fig. 1 is a front view of a laboratory balance
ing in the usual agate bearings 33 for the knife
constructed in accordance with the principles of
edges [4. Thus, the beam and ‘its operating
this invention:
mechanisms are supported in their proper posi
Fig. 2 is a rear view thereof;
tion within the case without the use of any in
Fig. 3 is an enlarged vertical section there 40 ternal post or pedestal.
through, taken on the line 3—3, Fig. 1;
The beam lifting yokes ll are secured to the
Fig. 4 is an enlarged fragmentary rear view
forward extremity of a horizontal bracket mem
with the cover plate removed to show the beam
ber 36, preferably T-shaped in cross section,
lifting rod;
Fig. 5 is a fragmentary horizontal section look
45
ing downward on the line 5-5, Fig. 3;
Fig. 6 is a similar section looking downward
on the line 6—6, Fig. 3; and
Fig. 7 is an enlarged fragmentary section taken
on the line l—-'l,.Fig. 4, illustrating the bearing
which is ?xedly formed on, and at right angles
to, a vertical lifting rod 31. The bracket member
extends through an opening 56 in the supporting
member.
The lifting rod 31 extends vertically
downward in a channel formed in the rear of the
member 24. The rod 31 is formed with two bear
for the lifting rod employed in the improved
ing portions 33, one being positioned adjacent
balance.
The principal feature of this invention is the
improved construction for supporting and lifting
the beam. The remainder of the balance may 55
the top of the rod and one adjacent the bottom
thereof. Opposite these portions of the rod, the
channel at the rear of the member 24 is formed
With two angularly-positioned, opposed, vertical
l
2
2,271,809
bearing surfaces 39, against which the bearing
of the plate frictionally engage the two sides of
the member 24 which are extended outwardly to
enclose the lift rod and channel. The vertical
A bearing plate 40 is secured across the chan
edges of the cover plate 50 extend into vertical
nel opposite each bearing portion 38 of the rod.
A U-shaped bearing piece 4| extends vertically Cl grooves 54 formed in the member 24 so as to
form a concealed joint with the supporting mem
between each plate 40 and the bearing portions
ber 24.
38 of the rod. The turned ends of the bearing
While a speci?c form of the improvement has
pieces 4| rest in notches in the upper and lower
been described and illustrated herein, it is de
edges of the plates 40. An adjusting screw 42
sired to be understood that the same may be
extends through each plate 40, by means of which
varied, within the scope of the appended claims,
its bearing piece 4| can be brought against the
without departing from the spirit of the inven
bearing portion of the rod to hold the latter
tion.
against its two opposed surfaces 39 without side
portion 38 of the rod rides.
'
Having thus described the invention, what is
claimed and desired secured by Letters Patent is:
1. In a laboratory balance, the combination
Thus, it can be seen that due to the fact that
with a case having side walls, a back wall, a top,
the bracket member 36 is formed at a ?xed angle
and a floor, a supporting member at the mid
with the rod 31, the overhanging weight thereof
portion of said back wall; a bracket member ex
is absorbed in the two three-line bearings on the
rod 31, formed by the inclined channel sides 20 tending forwardly into the case from said sup
porting member; means for supporting a scale
and the bearing pieces 4|.
beam from said bracket member; vertically
An adjustable lift screw 43 is threaded into the
aligned bearings on the rear of said supporting
lower extremity of the rod 31. The head of the
member; a lifting rod vertically slidable in said
screw 43 bears against an eccentric 44 secured
bearings; a beam lifting arm ?xed to said lift~
on an eccentric shaft 45 extending forwardly
ing rod at its upper extremity and extending for
across the case beneath the floor 23 and termi
wardly through said supporting member above
nating in a knurled head 46. Thus, by rotating
play and yet allowing free vertical movement
thereof.
the head 46 in one direction, the rod 31 can be
said bracket member, and means on said lifting
arm for lifting a beam from its bearings on said
forced upwardly to cause the lifting yokes l1 to
engage the studs l5 and lift the knife edges l4 30 bracket member.
2. In a laboratory balance, the combination
from their bearing agates 311. The amount of
with a case having side walls, a back wall, a
lift should be exceedingly small, possibly two
top, and a floor, a supporting member forming
thousandths of an inch, so that very little swing
the mid-portion of said back wall; a bracket
ing movement is imparted to the pans ||. The
member extending forwardly into the case from
amount of lift can be easily adjusted by means
said supporting member; means for supporting
of the adjustable lift screw 43. It is also essen
a scale beam from said bracket member; verti
tial that the lifting yokes |1 ascend in accurate
cally aligned bearings on the rear of said sup
vertical alignment with the studs I6 so that no
porting member; a lifting rod vertically slidable
sideward movement will be imparted to the
in said bearings; a beam lifting arm ?xed to
beam. This vertical alignment is attained by
said lifting rod at its upper extremity and ex
means of a guide post 41 which extends down
tending forwardly through said supporting mem
wardly through an enlarged opening 48 in the
ber above said bracket member, and means on
angle member 21. A contact screw 49 is threaded
said lifting arm for lifting a beam from its bear
into each side of the angle member into contact
with the post 41. By relative adjustment of
ings on said bracket member; each of said ver
tically aligned bearings comprising, a channel
these screws, the lifting yokes H can be accu
rately aligned with the studs It. The horizon
open on the rear of said supporting member,
tal bracket member 36 is perforated for the pas
oppositely inclined vertical side walls in said
sage of the bearing posts and is entirely free
channel against which said rod rests, and means
therefrom.
50 for holding said rod against said inclined side
The simplicity of the beam support and its lift
walls.
ing mechanism is apparent to anyone skilled in
3. In a laboratory balance, the combination
the art. All of the accurate drilling and ream
with a case having side walls, a back wall, a
ing for the lifting rod and the accurate machin
top, and a floor, a supporting member forming
ing of the lifting rod has been entirely elimi
the mid-portion of said back wall; a bracket
nated. The diameters of the rod are unimport
member extending forwardly into the case from
ant since it will always find a vertical bearing
said supporting member; means for supporting
against the angular surfaces 39 and no drilling
a scale beam from said bracket member; ver
or reaming is necessary Any looseness that
may develop in the usual construction re
quires entire rebuilding.
Any looseness which
may develop in this construction can be quickly
taken up by simply adjusting the screws 42. It
is also desired to call attention to the fact that no
?oor space is occupied by any beam supporting
mechanism. All supporting is accomplished
from the rear wall of the case.
tically aligned bearings on the rear of said sup
porting member; a lifting rod vertically slidable
in said bearings; a beam lifting arm ?xed to
said lifting rod at its upper extremity and ex
tending forwardly through said supporting mem
ber above said bracket member, means on said
lifting arm for lifting a beam from its bearings
on said bracket member; each of said vertically
aligned bearings comprising, a channel open on
The lifting mechanism and its bearings are
the rear of said supporting member, oppositely
concealed and protected by means of a channel
inclined vertical side walls in said channel against
shaped cover plate 50. The cover plate is formed 70 which said rod rests; a cover member extending
with a hinge rod 5| extending across its channel
across each channel, and an adjusting screw in
at the top thereof which engages in a receiving
each
cover member for urging said rod against
notch 52 in a projecting boss 53 on the member
said inclined side walls.
24. To place the cover plate in place, it is only
4. In a laboratory balance, the combination
necessary to engage the rod 5| in the slot 52 and
with a case having side walls, a back wall, a top,
then swing the cover plate inwardly. The sides
2,271,809
and a floor, a supporting member forming the
mid-portion of said back wall; a bracket mem
ber extending forwardly into the case from said
supporting member; means for supporting a scale
beam from said bracket member; vertically
aligned bearings on the rear of said supporting
member; a lifting rod vertically slidable in said
bearings; a beam lifting arm ?xed to said lifting
rod at its upper extremity and extending for
3
ing strap against said rod, said rod and its bear
ing channels being exposed on the rear of said
supporting member on the exterior of said case,
and a removable cover plate concealing the same.
6. Means for supporting the bearings of a lab
oratory scale beam and means for lifting said
beam from its bearings comprising: a vertical
supporting member; a bracket extending from
supporting member; bearing means carried
wardly through said supporting member above 10 said
by said bracket for said scale beam; an inverted,
said bracket member, means on said lifting arm
for lifting a beam from its bearings on said
bracket member; each of said vertically aligned
bearings comprising, a channel open on the rear
of said supporting member, oppositely inclined
vertical side walls in said channel against which
said rod rests; a bearing strap extending ver
tically against said rod opposite said inclined
side walls, and means for holding said bearing
strap against said rod.
5. In a laboratory balance, the combination
with a case having side walls, a back wall, a
top and a floor of a supporting member forming
the mid-portion of said back wall; a bracket
member extending forwardly into the case from
said supporting member; and means for sup
porting a scale beam from said bracket member,
vertically aligned bearings on the rear of said
supporting member; a lifting rod vertically slid
able in said bearings; a beam lifting arm ?xed
to said lifting rod at its upper extremity and
extending forwardly of said supporting member
L-shaped lifting member having a horizontal,
upper leg and a vertical lifting rod ?xedly joined
at right angles to each other, the lifting rod
extending between said beam and said bracket
member and carrying means for lifting the beam,
the rod extending vertically along one face of
the supporting member in a receiving channel
therein; oppositely inclined side walls in said
channel against which said rod bears along ver
tical lines; means for holding said rod against
said side walls; and means for lifting said rod.
7. Means for supporting the bearings of a lab
oratory scale beam and means for lifting said
beam from its bearings comprising: a vertical
supporting member; a bracket extending from
said supporting member; bearing means carried
by said bracket for said scale beam; an inverted,
L-shaped lifting member having a horizontal,
upper leg and a vertical lifting rod ?xedly joined
at right angles to each other, the lifting rod
extending between said beam and said bracket
member and carrying means for lifting the beam,
the rod extending vertically along’ one face of
above said bracket member, and means on said
lifting arm for lifting a beam from its bearings
the supporting member in a receiving channel '
on said bracket member, each of said vertically 35 therein; oppositely inclined side walls in said '
aligned bearings comprising, a channel open on
channel against which said rod bears along ver
the rear of said supporting member, oppositely
tical lines; a cover plate‘ extending across said
inclined, vertical side walls in said channel
channel; an adjusting screw in said cover plate
against which said rod rests, a bearing strap
for urging said rod against its inclined side walls;
extending vertically against said rod opposite said
and means for lifting said rod.
inclined side Walls, means for holding said bear
FRED W. THOMPSON.
Документ
Категория
Без категории
Просмотров
0
Размер файла
630 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа