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Патент USA US2408548

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Oct. 1, 1946.
Filed April 26; 1945
Patented Oct. 1, 1946
Joseph D. Bell, San Francisco, Calif.
Application April 26, 1943, Serial No. 484,646
6 Claims.
The present invention relates to improvements
in engines, and its principal object is to provide
improved means for transmitting motion from a
reciprocating piston to a rotary shaft. The pres
ent application is a continuation in part of my
co-pending application, Serial Number 434,094,
(01. 74-44) ’
I might say that my engine is intended partic
ularly to be of the slow speed type, while of
course, the principles involved may be developed
to apply to high speed engines.
Since the wedge drive is best adapted for wedg
ing the crank pin past dead center, while the
conventional piston rod drive operates best after
and introduces certain additional features tend
the crank arm has turned from dead center
ing to improve the operation of my invention,
through a considerable angle, I propose to utilize
The principal object of my invention is to in
troduce the principle of the Wedge drive into the 10 both drives, each at the point of its greatest ef?
ciency, and to provide means whereby the drive
transmission whereby the latter is rendered much
is shifted from the wedge to the conventional
more efficient than the vconventional connecting
piston rod' drive at a desired angle, and whereby
rod drive.
the shifting from one drive to the other takes
The wedge drive has been employed since time
immemorial for the lifting of heavy loads, and 15 place smoothly and without any sudden break in
the movement.
for transmitting power to perform heavy work,
And ?nally, it is proposed to provide a coop
and I have found through considerable experi
erating means tending to overcome any tendency
mentation that the wedge principle may be suc
at irregularity in motion or so-called slap that
cessfully employed in transmitting rotary move
might be inherent in the structure due to the dou
ment to a crank shaft from a reciprocating pis
ble drive on the crank pin.
ton at a great saving in power.
Further objects and advantages of my inven
It is well known that in the conventional con
tion will appear as the speci?cation progresses,
necting rod drive a great deal of power is lost
and the novel features of the same will be par
near the dead center points, and that the drive
does not really become ef?cient until after the 25 ticularly de?ned in the claims hereto attached.
The preferred forms of my invention are il
crank pin has passed the top dead center point
lustrated in the accompanying drawing, forming
by a considerable distance, while on the other
part of this application, in which:
hand, the efficiency becomes very low as the crank
Figure 1 shows a transverse sectional view
pin approaches bottom dead center.
In my present invention it is proposed to use 30 through my engine drive.
Figure 2, a section taken along line 2--2 of
a wedge drive,'particularly in the top dead center
Figure 1.
region whereby the power transmission is ren
Figure 3, a view of the same form showing the
dered very e?icient, and it is further proposed
connecting rod separate from the crank pin; and
to arrange the wedge drive in such a manner that
Figure 4, a fragmentary view of a slightly mod
it works'on the crank pin at a favorable lever 35
i?ed form of connecting rod.
age, which results in a corresponding increase in
While I have shown only the preferred form
I have found by practical experiments that to
lift a ten-pound weight by means of the conven
of my invention, I wish to have it understood
that various changes or modi?cations may be
40 made Within the scope of the claims hereto at
tional connecting rod drive, with the weight sus
tached without departing from the spirit of the
pended from a pulley equal in radius to the length
of the crank arm, it takes slightly above ten
Referring to the drawing in detail the piston
pounds to lift the weight when the force is ap
rod 2' is connected to the piston l’ by means of
plied With the crank arm in the most favorable
position, that is, at right angles to the direction 45 the pin 3’ and the crank shaft 4' has the crank
arms 5' and the crank pin 6' supported therein.
of force applied, while from that point in both
The crank is intended for rotation in clockwise
directions, the force necessary to lift the weight
direction, as indicated by the arrows‘.
rapidly increases to twenty or‘ thirty pounds.
The piston rod is formed with a slot 1' engag
In my invention, under the same conditions, I
ing over thercrank pin, with freedom of sliding
have found that the force necessary to lift the
ten-pound weight averages below ten pounds
movement, the slot being relatively short as com-'
throughout, and in fact, becomes quite low 'near
the dead centers, with the result thata relatively
small force will transmit a comparatively great
rollers mounted on opposite sides of the piston
amount of power.
pared with thediameter of the crank pin.
Wedging members 8' are shown in the form of
55 rod, somewhat to the rear of its centerline, and
wedging members 9’ are shown in the form of
crank pin and piston rod movement during the
eccentric cams secured upon the crank pin in
suction stroke only, a selected portion of the cam
the planes of the rollers for cooperation there
would be sufficient for this limited purpose.
with. The eccentrics are preferably positioned
In Figure 4 is shown a modi?ed form of slot 25
with their major axes leaning backward with re Cl for the piston rod 2', the slot being slightly kid
spect to the centerline of the drive when the
ney-shaped, that is, with a slight dent 26 in one
crank pin is in dead center position. Since only
side and a slight corresponding bulge 21 in the
the main projecting portion of each cam per
other side, and the slot is shown as being slightly
forms a function, the opposite portion, which
tilted with respect to the centerline of the piston
would substantially run into the outline of the 10 rod. This will offer a certain advantage on the
crank pin, has been omitted as shown at 20.
downstroke as tending to reduce friction during
The parts thus far described function substan
the wedging action.
tially as follows: At the beginning of the down
I claim:
ward stroke, the rollers 8' bearing on ‘the eccen
1. In a power transmitting device, a rotary
trics 9’ wedge the crank pin past dead ‘center in
member having a crank therein, a reciprocating
the direction shown in Figure 1, and, after the
member having a connecting rod pivoted thereto,
crank has reached a desired angle, the upper
cooperative wedge members on the crank and the
wall of slot 7’ bears down on the crank pin to
rod for transmitting motion from the rod to the
continue the drive.
crank, and cooperative members on the rod and
During the wedge drive, the slot '1’ of the pis
the crank for controlling lengthwise movement
‘ton rod on the side marked by numeral l3’ holds
with respect to the cam.
the wedging member 8’ in driving relation with
2. In a power transmitting device, a rotarir
cam ‘5’, until the upper wall of slot 1' takes over
member ‘having a crank therein, a reciprocating
the driving push. Just as the upper wall of the
member ‘having a connecting rod pivoted thereto,
‘slot has taken over the said drive, the wedging
cooperative wedge members on the rod and the
member 8'—“’ lose contact, but they are re
crank for rotating the crank when the recipro
engaged as the crank pin again approaches top
eating member moves toward the rotary member,
dead center, and they lift the piston rod back
means for vmaintaining the wedge members in
into its initial position.
driving relation during the wedging action, and
It appears desirable to provide ‘means for con 30 cooperative members on the crank and the rod
trolling relative movement between the piston
for controlling lengthwise movement of ‘the rod
and ‘crank pin outside of such movement as is
with respect to the crank.
inherent in the'desired drive, and to con?ne both
3. In a power transmitting device, a rotary
piston and crank pin to such co-related move
member having a crank therein, a reciprocating
ment as may be found by experience to develop
member having a connecting rod ‘pivoted thereto,
maximum e?iciency.
cooperative wedge members on the rod and the
To accomplish this I provide a pair of cooper
crank for rotating ‘the crank when the recipro
ating guide members on the piston and the crank
cating member moves toward the rotary mem
pin (on each side of the piston) in the form of
ber, means for maintaining the wedge members
a‘cam 2i and a roller 22.
The cam 23 is ?xed 40 in driving relation during ‘the wedging action,
to the crank pin and may be substantially con
centric with the latter, so that at the maximum
projection of ‘the cam 9' it is substantially ?ush
and cooperative members on ‘the crank and the
rod ‘for controlling lengthwise movement of the
rod with respect to ‘the crank, ‘the latter means
therewith, while diametrically opposite it pre
sents a relative wide margin beyond the cam 9'
comprising a cam on the crank and a cooperating
45 contact member ‘on ‘the rod.
even if the latter were continued clear around.
4.121 a power transmitting device, a rotary
member having va crank therein and having two
The relationship between the cams is most easily
understood by reference to Figure 3, which shows
cams of diiferent shapes on the crank, a recipro
the crank pin assembly by itself.
The rollers 22 are mounted on the piston rod,
in cooperative relation to the cams 2!, preferably
at the bottom and on the centerline, or possibly
diametrically opposite the rollers 8'.
eating member ‘having a connecting rod pivoted
thereto,‘means'including'a sliding connection and
engaging one of the'cams for transmitting move
ment from the rod to the crank and a member
on the rod ‘bearing on the second cam ‘for con
It will be noted that rollers 22 are always in
trolling the extent of the sliding movement.
contact with the faces of cams 2! at some point, 55
5. In- a power transmitting device, a rotary
while at the same time, on ‘the opposite side of
member ‘having a crank therein, a reciprocating
the center of cams 9’, either the upper wall of
member having a connecting rod pivoted thereto,
slot 1’ is engaged with the crank pin, or rollers
means including ‘a sliding connection ‘for trans
8' are engaged with cams s’. In either case,
mitting movement from vthe vrod to the crank and
there is suf?cient engagement, either between 60 cooperative means on ‘the crank and the rod for
the three walls of the slot 1', the rollers 22 and
controlling the extent of the sliding movement,
cams 2i, or between two walls of the slot 1’, the
the latter means comp-rising a cam on the crank
rollers 22 and cams 2i, combined with rollers 8'
and a cooperative contact member on the rod.
in engagement with cams 9', to prevent objec
6. In a power transmitting device, a rotary
tionable slap at all times.
65 member having a crank‘th'e'rein, a ‘reciprocating
The cam 2! is here shown as being circular in
member having a connecting rod pivoted thereto,
form, but that is not necessarily the most desir
the rod having a lengthwise slot engaging over
able shape. In fact, the cam would probably be
the crank and slidable thereon, cooperative wedge
slightly out of round or oblong, depending some
members on the rod and the crank ‘for transmit
what upon the amount of travel of the crank pin
ting ’motion from oneto the other, a cam on the
in the slot 1'. The exact form would best be
crank and a contact member on ‘the rod cooper
found experimentally, by tracing the desired
ating with the cam in controlling the extent of
course of the cam against the roller.
the sliding movement.
If it should be desired to con?ne the action of
the cam and the roller to coordination of ‘the
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