close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2095099

код для вставки
Oct. 5, 1937.
c. H. LITTLE
2,095,099
DRAFTING MACHINE
Filed Dec. 19, 1955
Sheets-Sheet 1
INVENTOR.
CHARLES H- L/TTAE
ATTORNEY5
Oct. 5, 1937.
2,095,099
c. H. LITTLE
DRAFTING MACHINE
Filed Dec. 19, 1935
2 Sheets-Sheet 2
FIG. 3
m VmR.
8
r}Z MW#0:E
“ M“
%
LA
5
2,095,099
Patented Oct. 5, 1937
UNITED STATES
PATENT OFFICE
2,095,099
nnar'rmo MACHINE
Charles a. Little, Cleveland Heights, Ohio
Application December 19, 1935, Serial No. 55,251
'1 Claims. (Cl. 33-'-79)
The present invention relates to drafting ma
chines of the wheel and band type, and more
applied to the band forming part of the protrac
tor parallelogram of the drafting machine shown
particularly to a guard or means for enclosing or
in Fig. 1; and
partially enclosing the band or bands thereof,
especially that portion of the band adjacent to
the protractor.
In the present day machines of the wheel and
band type the sharp edges of the bands are
ordinarily exposed over a considerable distance
10
and the operator is constantly exposed to the
danger of being cut or otherwise injured thereby.
This is especially true of that part of the band
adjacent to the protractor, which, during opera
tion, is rotated back and forth over the wheel
' immediately underneath or adjacent to the oper
ator’s hand. The possibility of the band breaking
under the high tension to which it is subject,
furthéer subjects the operator to the danger of
being injured by the ?ying band if either of the
20 bands employed should break under the consider
able tension at which they are operated. In order
to keep the bands taut and to prevent the same
from slipping on the wheels, it is not uncommon
for them to be operated under a tension of one
hundred pounds or more and they are stretched
accordingly. The back and forth rotation of the
bands over the wheels causes crystallization
thereof, due to which, or for various other rea
sons, the band is liable to break at any time
causing possible serious injury to the operator.
The object of the present invention is the pro
vision of a drafting machine of the wheel and
band type provided with a novel guard or cover
for the band adjacent the protractor which will
CG CI protect the operator from being cut or otherwise
injured thereby, together with means for stopping
the force of the bands in the event they should
break during operation of the machine.
The present invention resides in certain novel
40 details of construction and combinations and
arrangements of parts, and further advantages
thereof will be apparent to those skilled in the
art from the following description of the pre
ferred embodiment thereof, described with refer
ence to the accompanying drawings forming a
part of this speci?cation, in which similar refer
ence characters designate corresponding parts
throughout the several views, and in which:
Fig. 1 is a plan view of a drafting machine
50
embodying the present invention;
Fig. 2 is a front elevation of the protractor end
of modi?ed construction.
.
Referring to the drawings,v the drafting ma
chine shown therein comprises a parallel motion
mechanism or arm provided at one end with a
movable anchor A for attachment to a drawing
board or table, and at the other end with a pro 10
tractor assembly or head 13 including rulers l0
and II, etc. The parallel motion mechanism or
arm consists of two parallelograms comprising
endless ?at ?exible steel bands I2 and 13 en
circling equal diameter wheels held apart or in 15
spaced relation by adjustable struts C and D,
comprising tubular members ll provided with
end members i5 and I6 of any suitable shape,
which project over the respective wheels and
with respect to which they are rotatably con 20
nected.
‘
The protractor assembly B, per se, forms no
part of the present invention and a detailed de
scription thereof will not begiven. Suf?ce it to
say that preferably it is of the type which per- 25
mits rotation of the rulers through 360°. The
bands I 2 and i3 are preferably unattached to
the wheels except for the friction therebetween.
This construction allows the elbow of the arm
to be thrown to either side of the center line, "
thereby enabling every part of the board or table
to be reached. ,
>
As previously stated, the present invention con
templates means for protecting the operator from
injury by the band. To this end I have provided 35
a guard, designated generally by the reference
character E, which forms a ,complete‘cover for
that part or end of the band 13 adjacent the
protractor assembly. The guard may be of any
desired shape or construction so long as it pre
vents the hand of the operator from comingin
contact with the band or being caught between
the wheel and band during the normal operation
of the machine. As illustrated, the guard E com
prises a sector shaped portion 20 carried by or
attached to the right hand end of the member it
of the strut D, by a ?ange 2|, and provided with
two channel shaped members or rods 22 and 23
formed integral therewith, projecting towards
the left as viewed in the drawings. The outside 50
?anges 25 and 26 of the channel shaped mem
Fig. 3 is a perspective view of the guard or
cover for the band adjacent the protractor;
bers continue around the edge of the sector
shaped portion 20 to form a closed end about the
band. The channel shaped members or rods 22
Figs. 4 and 5 are perspective views of the guards
and 23 open downwardly, enclosing the band I3
of the drafting machine shown in Fig. 1;
55
'
Figs. 6, 7 and 8 are sectional views of bands
2
2,095,099
_
.
on three sides, and extend towards the elbow of . coating rubber or some such material on the inside
the machine a suitable distance where they are of the band also increases the friction between
connected to and supported by- the strut D the band and wheels, thereby reducing the tension
through the medium of a cross member 21 riveted required to prevent relative rotation therebe
or otherwise secured to the ends thereof and
connected to the strut in any convenient or suit
While the preferred embodiments of the inven
tween.
able manner. From the foregoing description of
the guard E, it will be apparent that with the
present construction it is impossible for the oper
ator to be injured by the band l3 either in the
normal operation of the machine or in' the event
the same should break.
I have also provided means for preventing the
band l2 of the anchor parallelogram from ?ying,
15 in the event it should break.
.
a
1
tion have been illustrated and described, I do not
wish to be limited to the particular construction
shown, which may be varied within the scope of
this invention, and I particularly point out and
claim as my invention the following:
'
10
l. A drafting ‘machine comprising a parallel
motion am, said arm comprising a plurality of
wheels, a ?exible band operatively connected to
Two different forms ' said wheels, a center strut operatively connected
of guards, designated generally by the reference
to said wheels for maintaining the same in spaced
characters F and H, are shown.
relation, and a guard attached to said strut cov
These‘ guards
maybe used together, as shown, or separately, as ering at least a portion of said band. '
will be hereafter more readily apparent. The ,_, __2. A drafting machine comprising a parallel
guard 1" consists of two channel shaped, rods or motion arm, said arm comprising a plurality of
members 30 and 3| opening downwardly, enclos
wheels, a ?exible endless‘ band extending about 20
ing opposite sides of the band i2 on three sides, the wheels, a center strut operatively connected
pivotally connected as by rivets 32 to opposite to the wheels for maintaining the same in spaced
ends of a cross member 33 carried by the strut C. relation, and guard means attached to the'strut g
The top and inside ?anges of channel shaped rods and extending laterally thereof vadjacent the 25
are preferably cut away intermediate the ends
band.
thereof forthe purpose of reducing the weight
3. A drafting machine comprising a parallel
motion arm, said am comprising’a plurality of
etc. As illustrated the rods 30 and 3| vare con
nected to the cross member 33 adjacent their
30 upper ends and the construction is such that if
the band breaks below the pivot or rivets 32, that
is, between the pivot and the elbow of the arm,
the movement of.,the free ends of the'band will
cause the rods 33 and 3| to pivot and kink or hold
the band within the channel thereof. If desired,
the ends of the ?anges of the rods or members 30
and 3| may be'bent inward, as shown at 34, to
assist in kinking and gripping the band upon
failure thereof. In the embodiment illustrated
(0 the rods 33 and 3| are relatively short and are
used in conjunction with the guards H, but the
latter guards may be omitted and the rods 30 and
3| extended to enclose any desired proportion ‘of
the band l3.
.
The guards H merely consist of a strip of metal
43 secured to the strut C and having the ends 4| '
bent in such a manner that they substantially
encircle the sides of the band l3. This construc
tion is very simple but effective and any desired
50 number of such guards may be employed. It will
also be apparent that the rods or members 22 and
23 of the guard E may be omitted altogether or
extend only a short distance from the protractor
assembly, and if desired, supplemented by one or
55 more guards similar to the guards F or H. If the
I rods or members 22 and 23 are made relatively
short, the support for the left hand ends thereof
may be omitted.
The possibility of the operator being injured
by the sharp edges of the band may be lessened
to some extent by either rounding the edges of
the band, or by coating or covering the edges
-
wheels, a ?exible endless band operatively con
nected to said wheels, a strut operatively con-' 30
nected to said wheels for maintaining the same
in spaced relation, and a pivoted guard member
supported by said strut and extending adjacent
to the band.
4. A drafting machine comprising a parallel 35.
motion arm, said arm comprising a pair ofwheels,
a ?exible band operatively connected to said
wheels, a center strut operatively connected to
said wheels for maintaining the same in spaced
relation, a protractor assembly operatively con
nected to one end of said arm, and a guard car
ried by said strut covering a portion of said band
adjacent said protractor assembly.
5. A drafting machine comprising a parallel
motion arm having a section including a plurality 45
of wheels, an endless ?exible band extending
about said wheels, a strut operatively connected
to the wheels for maintaining the same in spaced
relation, and a guard carried by said strut and
covering the curved portion of the band adjacent
one end of the arm section.
6. A drafting machine comprising a ‘parallel
motion arm having a section including a plurality
of wheels, an endless ?exible band extending
about said wheels, a strut operatively connected
to the wheels for maintaining the same in spaced
relation,-and a guard carried by said strut and
covering the curved portion of said band adjacent
one end of the section and also portions of the
straight sections of the band extending from said
curved portion.
I
7. A drafting machine comprising a parallel
thereof or the entire band with a non-metallic motion arm having a section including a plurality
substance such as rubber or the like. Fig. 6 of wheels, an endless ?exible band having curved
shows a band ll having rounded edges, as sug
portions extending about said wheels, and ‘a strut
gested above, Fig. 7 shows a band 48 having the . operatively connected to the wheels for maintain
sides thereof covered or ‘coated with rubber or the ing the-same in spaced relation, said strut having
like designated by the reference character 41, and a guard covering the outer side of at least a por
l?g.-8 shows an entire band vl8 provided with a
70 rubber or non-metallic coating 49. The use of a
tion of the curved part of said band.
._
I
CHARLES H. LITTLE.
'
70
Документ
Категория
Без категории
Просмотров
0
Размер файла
373 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа