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Патент USA US3094119

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June 18, 1963
Filed Feb. 23', 1961
2 Sheets-Sheet 1
June 18, 1963
Filed Feb. 23, 1961
2 Sheets-Sheet 2
58. 8% e4‘, 5/2.
I‘ ,
United States Patent O?ice
William L. El?nger, Jr., Harnden, Comm, assignor to The
Patented June 18, 1963
Another object is to provide such brake means ar
ranged to perform its automatic coupling and uncoupling
action by the action of centrifugal force.
Another object is to enable the engine driven rotor
to become uncoupled from the engine body before it
A. C. Gilbert Company, New Haven, Conn, a corpora
has completely dissipated the energy stored therein by
tion of Maryland
its manual prewinding for starting the engine.
Filed Feb. 23, 1961, Ser. No. 91,032
The foregoing and other objects of the invention will
12 Claims. (Cl. 123-179)
become apparent from the following description of suc
This invention relates to starting devices for internal 10 cessful embodiments of the improvements having refer
combustion engines particularly of the very small sizes
ence to the appended drawings wherein:
used to drive model airplanes, boats, toy vehicles and
FIG. 1 is a perspective external view of a miniature
the like.
single cylinder internal combustion engine rigged to drive
It has been proposed to start such engines by manually
a toy airplane propeller and incorporating starting de
tensioning a spiral spring and then releasing it to whirl 15 vices embodying the invention.
the engine shaft in running ‘direction. The spring has
FIG. 2 is a somewhat similar view of the same engine
been so tensioned by a few spring winding manually
with the propeller ‘and starting devices removed to expose
impelled turns of the engine-driven rotor in backward
the crankshaft of the engine.
direction opposite to the intended direction of engine
FIG. 3 is a perspective view of the starting devices
running. In the case of a toy airplane engine, the rotor 20 removed from the propeller and the engine parts of
FIGS. 1 and 2.
is a driven propeller ?xed to the engine shaft and serving
as a crank handle by which to wind up the spring for
FIG. 4 is a fragmentary enlarged side elevation of the
engine starting action when manually released. Obvi
engine, propeller and starting devices in FIG. 1 showing
ously when once started and engine driven the propeller
the starting device vand propeller hub in section on angu
shaft must be able to continue its engine driven rotation 25 larly related radial planes 4-4 in FIG. 5.
in the proper direction free of hindrance by the spring.
FIG. 5 is a view taken in section on the plane 5-5 in
Many engines of the type here most concerned can
FIG. 4 looking in the direction of the arrows.
?re as readily in one direction of running as in the other,
FIG. 6 is a view taken in section on the plane 6-6
depending on minute variations in the time and speed
in FIG. 4 looking in the direction of the arrows.
of the crankshaft with respect to occurrence of the ex 30
FIG. 7 is a view similar to FIG. 5 showing on an
plosion when the piston reaches and passes top center
enlarged scale a modi?ed embodiment of the invention.
in the stroke of the crankshaft.
FIG. 8 is a view taken in section on the plane 8-8
Thus an engine of this type after starting to run in
in FIG. 7 looking in the direction of the arrows.
one direction can, upon suf?cient reduction of speed
FIG. 9 shows a modi?ed construction of the centrifugal
incurred by increase in load, or failure of fuel supply, 35 clutch of FIGS. 7 and 8.
automatically reverse its direction of running for lack
FIG. 1'10 shows a further modi?ed construction of cen
of sufficient momentum in the moving parts to carry the
trlifugal clutch taken partially in section ‘on a diametral
p ane.
piston fully over top center at the time the engine ?res.
It has been proposed to accomplish such automatic
FIG. 11 is a view taken in section on the plane 11--1‘1
freeing of the engine shaft from the driving action of
in FIG. 10 looking in the direction of the arrows.
the spring by permanently anchoring one end of the
FIG. 1 represents the body 12 of a typical miniature
starter spring to the engine body and permitting the
single cylinder combustion engine equipped at each side
opposite end of the spring to uncouple automatically
with a lug 13 containing holes 14 for mounting the en
from its rotor driving connection. Hence, prior to the
gine removably on the framework of a toy airplane (not
present improvement, it has been proposed that the starter 45 shown) or other small craft, boat or vehicle to be pow
spring remain stationary with the engine body after hav
ered by the engine. Engine ‘body ‘12 conventionally in
ing functioned to start the engine.
cludes a power cylinder 15, an air intake 16, a fuel
In this previous way of starting engines there has been
intake 17, exhaust cooling ?ns ‘18 and the crankcase 119.
no safeguard against ?ring of the engine in a way that
The crankcase portion of the engine body includes
can run the engine in the wrong direction. Frequent 50 bearing structure 211 in which the crank shaft 20 is
need of corrective stopping and restarting of the engine
journalled. Such structure comprises a cylindrical boss
has been taken for granted.
containing an external notch 24 providing a stationary
An object of this invention is to provide a spring action
detent shoulder 22. The crankshaft projects from its
starting device of required simplicity, low cost, durability,
bearing to receive ?xedly on its knurled portion 30 the
and positiveness of action which positively restricts run 55 hub 31 of an engine driven rotor including the hollow
ning of the engine to a single intended forward direction
spring barrel 32. Barrel 32 always turns in unison with
of rotation at all times.
shaft 20 and houses between its rim- 33- and the stationary
A related object is similarly to inhibit running of the
boss 21 of the engine body a spirally coiled engine start
engine in reverse or backward direction even if the engine
ing band spring 34 having its outer end permanently
attempts to reverse its direction of running at any time 60 secured to the drum ring 33 by a rivet 37 ‘and carrying
after having been started initially in the forward or
?xed to its inner end by rivets 36 a weighty catch or latch
right direction.
35. Spring 34 is so resiliently conditioned that it nor
mally biases the latch 35 radially inward into wiping
Another object is to enable the starter spring to rotate
contact with boss 21 so that the latch automatically
bodily in unison with the engine ‘driven rotor instead of
remaining stationary with the engine body, so that the 65 seeks and becomes seated in the stationary notch 24 in
hooked engagement with a keeper for-med by the detent
weight of the revolving starter parts may serve as a
shoulder 22.
fly-wheel on the engine shaft with bene?t to the smooth
ness of running of the engine.
Latch 35 has su?icient weight to be sensitive to cen
Another object is to interpose improved brake means
trifugal force and thereby can be ?ung radially out
between the starter spring and ‘the engine body as part 70 ward away ‘from hearing boss 21 and clear of the notch
of connections operatively couplingthe engine driven
shoulder 22 by rapid speed of rotation of barrel 32 with
rotor to the engine body.
engine shaft 20' when such force is great enough to
l l
overcome. the. natural bias in spring 34 and cause ?exure
of the. spring in an unwinding direction. Thus the en
gagement and disengagement of catch or latch 35 with
notch shoulder 22 of the keeper functions automatically
in response to variation in speed of the engine shaft in
such manner that when stationary, or revolving at rela
tively slow speed, the turning of shaft 20 counterclock
wise in FIG. 5 (clockwise in FIGS. 1 and 6) will act
to permit engine drive of the propeller in forward di
rection, namely counterclockwise in FIGS. 1 and 6 (clock
wise in FIG. 5) because the catch can always ride freely
out of notch 24 in ‘that direction.
The above described characteristics of a starter operat
ing on the principles of this invention differ from com
parable starters, as heretofore constructed and function
ing, in that the starter spring in previously known starters
has been disenabled to operatively connect the engine
sion therein which subsequently can operate automati 10 driven rotor and the engine body by a break in trans
mission of spring power to the engine driven rotor instead
cally to whirl shaft 20 in counterclockwise or forward
of by breaking the retentive anchorage of the spring to the
running direction in FIGS. 1 and 6 (clockwise in FIG.
stationary engine body, and the disenabling of the starter
5.). This will whirl the crankshaft so rapidly past top
to wind up spring 34 to a limited extent and store ten
center position of the piston that starting of the engine
spring can occur before it has become completely un
ordinarily will take place in the intended forward di-. 15 wound or deenergized. The bene?ts arising from the
present improvements are derived in part from ability of
rection, If it does not, and if; faulty ?ring causes acci
dental starting of the engine in reverse direction, the
the starter spring to become thus automatically freed by
catch 35 immediately reengages with notch shoulder 22
centrifugal force from anchorage to the engine body even
‘and checks turning of the shaft in such wrong direction
while the spring remains partially energized.
whereupon the momentum of the rotor parts such as 32
turning in wrong direction will automatically repeat a
winding up of the spring so that when the back ?ring
force of the engine is spent the spring will again auto
In the modi?ed construction shown in FIGS. 7 and 8,
the radially outermost end of the starter spring 34’ is per
manently secured by a rivet 37 to the rim 33 of an en
gine driven rotor which includes the spring barrel 32 as
in FIGS. 1 to 6. But in place of a catch like 35 ?oating
gine running direction and thereby restart the engine 25 with the radially innermost end of spring 34’ the inner
in proper direction without manual attention. Such au
spring end is permanently secured to the rim 49 of a cup
tomatic checking of backward rotation followed by en
shaped brake ring 50 by a rivet 51. This ring has a loose
matically function to whirl the shaft in forward or en
gine restarting automatic drive of‘ the shaft in forward
running ?t in a circumferential bearing groove 52 on the
direction will occur at any time when temporary reduction
of speed results in accidental back-?ring of the engine
while it is running.
In the drawings the load to be rotated by crankshaft
20 is represented by the propeller 49 of a toy or model
aircraft whose hub 41 is ?xedly interlocked with spring
barrel 32 by the mutual engagement of radially disposed
and mating ridges and grooves 42 on the propeller hub
and ‘43 on the mating face of the barrel hub 31. The
propeller is removably secured on the crankshaft 20 by
a retaining nut 44 and slip washer 45.
In starting an engine by use of the invention when 40
external cylindrical surface of the boss 21’ of the engine
body 19 thus deriving axial thrust from the side shoulders
of such groove. Within the annular space intermediate
the rim 49 of the brake ring 56 and the bearing boss 21'
embodied in the form of mechanism shown in FIGS.
1 to 6, inclusive, the engine is assumed ?rst to be, at
rest with the catch 35 biased against, the stationary
there are pivotally carried two or more detent pawls 53
independently swingable on pivot studs 54 ?xed in the
web wall 55 of brake ring 50, preferably at diametrically
opposite sides of the ring respectively.
Each pawl 53 is individually biased by a short leaf
spring 56 ?xed thereon and bearing outward against the
inner surface of ring rim 49 in a manner constantly to
urge the hook head 57 of the pawl toward the stationary
bearing boss 21' and into releasable latching engagement
with either of the shoulders 22 of notches 24 in the sta
tionary bearing boss. Each pawl head 57 is weighted by
bearing boss 21, ready automatically to enter the notch
an insert 58 of substance such as lead or steel having heav
,24 in releasable hooking relation to notch shoulder 22. 45 ier speci?c gravity than the material of the pawl which
A ?nger of the operator’s hand is applied to impeller
may be nylon. Such weighting will aid in enabling cen
40 in a manner to swing it a few turns clockwise as
trifugal force exerted on the pawl head to overcome the
viewed in FIG. 1. The catch 35 will seek and enter
resilient resistance of pawl springs 56 and swing the pawl
the notch 24 and be held stationary by notch shoulder
counterclockwise in FIG. 7 and out of detentive engage
22 while a subsequent few turns of the spring barrel 32 50 ment with notch shoulder 22 and maintain such disengage
clockwise in FIG. -1 prewind or store up engine starting
ment as long as brake ring 50 is rotated by engine drive
tension in the spring. The operator’s ?nger ‘tip, can then
be withdrawn abruptly and safely from the extreme end
of the propeller blade. Spring 34 will immediately de
with su?icient angular speed to generate the required
centrifugal force.
turns clockwise. Engine shaft 20 thereby becomes effec
thrusts against, instead of pulling on, the keeper shoulder
63 of notch 62 in the bearing boss 61 of the engine body.
This keeper shoulder is inclined at a slightly obtuse angle
The pawls 53 are sometimes referred to herein as the
liver its stored up energy to the rotor 32 by rapid un 55 latch elements of a centrifugal brake. A simpli?ed form
winding ?exure which whirls spring barrel 33 a few
of such pawls is shown at 53' in FIG. 9 wherein the pawl
tively “cranked” in engine running direction causing the
engine to ?re and take over the drive of the shaft, the
spring, spring barrel and the propeller, all in unison. 60 rather than an acute angle with respect to tangency to its
Thereupon these engine driven rotor parts pick up
circle of rotation.
and run ahead of the initial rotor driving action of the
In FIG. 9 one of the pawls 53' is shown drivingly en
starter spring. Catch 35 will be ?ung by centrifugal
gaged with its keeper shoulder 63 while the other is
force radially outward away from its anchored reten
shown disengaged therefrom merely to illustrate the en
tion by keeper 22 as permitted by flexure of the starter
gaged and disengaged positions between which the pawl
spring 34 and Will be maintained thus freed from en
can swing. It will be observed that the eccentric portion
gagement with bearing boss 21 so long as the engine
of the pawl body that engages the keeper shoulder 63 is
continues to impart rapid; rotation to the spring as the
more massive than in the pawls 53 of FIG. 7 whereby to
latter travels in unison with the engine driven rotor.
be self reactive to gravity and centrifugal force so that
In the absence of the action of centrifugal force, spring 70 pawls 53’ will fall into engagement with notches 62, and
34 could not be relied on to insure starting or automatic
automatically withdraw therefrom, without need of pawl
restarting of the engine. in correct or forward direction
biasing springs such as 56 in FIG. 7. Pawls such as 53'
in the event of backward ?ring of the engine. How
are preferably made very loosely swingable about their
ever the action of such centrifugal ‘force is not necessary
pivot studs 54.
for freeing catch 35 from notch shoulder 22 merely 75
FIGS. 10 and 11 show a still further modi?ed con
struction wherein ring 68 drives brake ring 67 and to
gether therewith and can be anchored against rotation at
of said spring in position to be permitted by ?exure of
said spring to engage retentively with and to disengage
respectively di?ferent speeds as well as in predetermined
direction, by a claw tooth or teeth 66 projecting from and
forming part of a brake ring 67. This provides a claw
from said keeper.
type of centrifugal brake in which ring 67 is joined by
leaf springs 73 in spaced and axially slidable relation to
automatically from retentive engagement with the said
keeper by centrifugal force exerted on the said starter
spring and generated by relatively high angular speeds of
4. The combination de?ned in claim 3, in which the
said latch is weighted in a manner to be caused to escape
‘clutch ring 68, which latter is arranged and connected to
function in relation to the other parts of the starter like
said rotor and said spring in unison.
part 50 in FIGS. 7 to 9 inclusive.
5. The combination de?ned in claim 4, in which the
‘In FIGS. 10 and 11 an axially facing shoulder 69 on
said starter spring is statically conditioned by its own
bearing boss 70 is provided with as many notches 71 hav
resilience to bias the said latch in direction to seek and
ing keeper shoulders 72 as there are claw teeth 66 on
automatically resume retentive engagement with the said
brake ring 67, all being equally spaced circumferentially.
keeper when relieved of the said centrifugal force after
Brake ring ‘67 is joined to ring 68 ‘by two or more pairs
being disengaged thereby from said keeper.
of the aforesaid radially extending bowed spring leaf
6. The combination de?ned in claim 1, in which the
arms 73 which at their radially outermost ends are ?xed
said brake means comprises, a stationary keeper on the
together and ?xedly carry weights 74. When brake ring
engine body, a brake ring drivably connected to the said
67 is driven to rapid rotation through spring arms 73
engine starting resilient means, a rotor bearing con?ning
by ring 67 the radially outward pull of weights 74 on 20 said brake ring to circular movement coaxially of the said
the bowed spring arms 73 in response to centrifugal force
engine driven rotor, and at least one latch element driven
tend to straighten the spring arms with consequent draw
by the said brake ring in shiftable relation thereto in a
ing of brake ring 67 toward the left in FIG. 10'. There
circular path enabling said element by shifting position
upon all of the claw teeth 66 become disengaged from the
relatively to said brake ring to engage retentively with
stationary bearing boss notches 71 and free brake ring 25 and disengage from the said keeper on respectively differ
67 from anchorage coupling to the body of the engine.
In the absence of sufficiently high speed of rotation of
ent occasions.
ring 68 the resilience in spring arms 73 restores the brake
latch element is a detent pawl pivotally mounted on the
7. The combination de?ned in claim 6, in which the said
ring 67 into anchored engagement with the stationary
said brake ring in swingable relation thereto.
bearing boss 7 0 of the engine body.
8. The combination de?ned in claim 7, in which the
Certain advantages arise from maintaining the starter
said detent pawl is shaped and disposed in respect to its
spring permanently connected to the engine driven rotor
mounting on the said brake ring to be urged to shift
so as always to travel bodily in unison therewith whether
the brake is a centrifugal clutch or simply a one-way hold
relatively thereto in a direction to disengage automatically
from the said keeper responsively to centrifugal force gen
ing brake permitting the engine driven rotor to outrun 35 erated by rotation of said brake ring.
the initial driving action of the starter spring in one di
9. The combination de?ned in claim 8, together with a
rection. These and all other variations of the exact kind
spring reactive between the said brake ring and the said
and arrangements of parts herein proposed are intended
detent pawl urging the latter in direction to engage de
to be covered by the appended claims if coming within
tentively with the said keeper.
a broad interpretation of their terminology.
10. The combination de?ned in claim 6, in which the
What is claimed is:
said latch element is shiftable in relation to the said brake
l. The combination with the driven rotor and stationary
ring in a direction parallel with the axis of rotation of
body of an internal combustion engine of, connections for
the latter.
elastically coupling said rotor to said engine body com
11. The combination de?ned in claim 10, together with
prising at least in part, engine starting resilient means 45 a governor
spring connecting the said latch element to the
permanently attached to said rotor to travel in unison
said brake ring in a manner to bias said element toward
therewith, and positively self latching brake means opera
the said keeper, and a weight carried by said governor
tively interposed between said resilient means and said
spring in a manner to ?ex said governor spring in direc
engine body operative automatically to couple and un
to disengage said latch element from retentive engage
couple said rotor and engine body in respectively opposite
ment with said keeper in response to centrifugal force
directions of rotation of the former relative to the latter.
generated by rotation of said brake ring.
2. The combination with the driven rotor and stationary
12. The combination de?ned in claim 1, in which the
body of an internal combustion engine of, connections for
direction of rotation in which the said self latching
elastically coupling said rotor to said engine body com
prising at least in part, engine starting resilient means 55 brake means is operative automatically to uncouple the
said rotor and the said engine body is the same rotary
permanently attached to said rotor to travel in unison
direction as that in which the engine is started to run by
therewith, and self latching brake means including a
the power of the said resilient means, whereby said rotor
keeper in ?xed relation to said engine body and a catch
must be turned in the opposite direction to tension said
cooperative with said keeper mounted to revolve with
resilient means to deliver said power.
said rotor and shiftable relatively thereto in- a direction
automatically to couple and uncouple said rotor and engine
References Cited in the ?le of this patent
body responsively respectively to changes in centrifugal
force at diiferent angular speeds of rotation of said rotor
relative to said engine body.
McRoskey et a1. _______ __ Oct. 7, 1958
3. The combination de?ned in claim 1, in which the 65 2,869,682
De Millar _________ __v__ Jan. 20, 1959‘
said resilient means is a coiled starter spring and the said
brake means comprises a stationary keeper on the said
engine body cooperative with a latch carried on an end
Barr ________________ __ Mar. 10, 1959*
De Groat ____________ __ Mar. 8, 1960
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