U.S. patent number 3,742,928 [Application Number 05/257,828] was granted by the patent office on 1973-07-03 for safety throttle for internal combustion engines.
This patent grant is currently assigned to Zeal Corporation. Invention is credited to Robert V. Albertson.
United States Patent |
3,742,928 |
Albertson |
July 3, 1973 |
SAFETY THROTTLE FOR INTERNAL COMBUSTION ENGINES
Abstract
A safety device for a throttle of the type which regulates a
carburetor gas flow valve by means of a throttle cable fixedly
connected at one end to a throttle lever and at its other end to a
gas flow control valve and in which the cable normally moves
reciprocally in a passageway as the throttle lever moves between
open and closed positions. An ignition circuit safety switch is
provided and safety switch control means are provided in the
passageway out of contact with a cable moving in normal
reciprocable fashion. For abnormal cable movement, however, the
cable is distorted in the passageway causing the cable to strike
the safety switch control means whereupon the safety switch
operates to shut off or otherwise disable the engine controlled by
the throttle. In one embodiment, the safety switch control means is
also manually moveable into contact with the cable irrespective of
the cable position or movement to provide for manual shutting off
of the engine.
Inventors: |
Albertson; Robert V. (Wayzata,
MN) |
Assignee: |
Zeal Corporation (Excelsior,
MN)
|
Family
ID: |
22977927 |
Appl.
No.: |
05/257,828 |
Filed: |
May 30, 1972 |
Current U.S.
Class: |
123/198DC;
180/271; 200/61.86 |
Current CPC
Class: |
F02D
11/02 (20130101); B60K 28/00 (20130101); F02D
17/04 (20130101); B62K 23/02 (20130101); H01H
2009/068 (20130101) |
Current International
Class: |
B60K
28/00 (20060101); F02D 11/00 (20060101); F02D
17/00 (20060101); F02D 17/04 (20060101); F02D
11/02 (20060101); F02b 077/08 (); B60k 033/00 ();
F02d 011/04 () |
Field of
Search: |
;123/198D,198DB,198DC,108,98 ;180/82,103 ;200/61.86,61.89,61.90
;340/53 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Al Lawrence
Claims
What is claimed is:
1. In combination with an internal combustion engine having a
throttle cable fixedly connected at one end to a throttle control
lever and at the other end to a gas flow control valve, and a
passageway for said cable having a cross-section larger than said
cable and in which the cable normally moves reciprocally as said
throttle lever is moved between open and closed positions, an
improved safety switch for enabling and disabling an ignition
circuit of the engine comprising:
a. switch control means having an electrical conductor mounted
adjacent to and accessible from said passageway but disposed out of
contact with said cable during normal reciprocal movement of said
cable in said passageway but contactable by said cable when, upon
movement of said throttle lever toward the closed position,
movement of said cable in said passageway is inhibited to produce
cable distortion which urges said cable into contact with said
conductor, and
b. means coupling said ignition circuit to said conductor whereby
said ignition is grounded when said distorted cable is urged into
contact with said conductor.
2. A safety switch as in claim 1 further comprising:
a. means mounting said switch control means adjacent said
passageway such that said conductor is moveable transverse to said
passageway between a first position permitting striking of said
conductor by said cable upon distortion of the cable and a second
position wherein said conductor is manually projected into contact
with said cable whereby grounding of said ignition can be manually
effected by movement of said conductor from said first to said
second position.
3. A safety switch as in claim 2 further comprising:
a. means for electrically insulating said conductor from ground
potential except through striking said cable.
4. A safety switch as in claim 3 further comprising:
a. bias means urging said conductor to its first position whereby
said conductor must be manually moved to its second position.
Description
BACKGROUND OF THE INVENTION
The present invention relates to throttles in general and in
particular to safety throttles, i.e., to throttles which turn off
or otherwise disable the engine controlled by the throttle upon
occurrence of conditions deemed unsafe.
Many vehicles such as snowmobiles, all terrain vehicles, minibikes,
etc. have a throttle system including a gas flow control valve on
the carburetor, a manually operable rotatable, throttle lever which
is usually mounted on a steering handle bar, and a steel cable
which connects the throttle lever to the gas flow control
valve.
The flexible cable is conventionally encased totally or, at least
partially, in a flexible steel sheath which serves to guide and
protect the cable. It is well known that these cables must be
properly lubricated regularly to prevent undue wear and sticking.
However, wear does occur and, eventually, because of either lack of
lubrication or otherwise, the cable becomes frayed and may stick or
bind. Also, the cable may stick because liquids, e.g., moisture
from condensation, from a break in the shroud, or indeed even the
lubricant itself, freeze in the cable shroud. Should the cable
become stuck in the open position, i.e., in the position in which
the gas flow control valve is open, serious injuries to the
operator and property damage could result.
In applicant's copending application, Ser. No. 71,600, filed Sept.
11, 1970, now U.S. Pat. No. 3,672,344, and entitled SAFETY DEVICE
FOR AN INTERNAL COMBUSTION ENGINE, there is disclosed an invention
which overcomes the disadvantages of the piror art throttle control
systems by providing a device for grounding the vehicle's
electrical ignition circuit whenever the throttle cable sticks in
an open position, thus preventing the engine from running and
therefore, preventing needless injury to individuals and damage to
valuable property. In accordance with the teaching of that
invention, disabling of the ignition circuit is accomplished by a
pair of cooperating electrical contacts of an ignition circuit
safety switch, one of the contacts being fixed to the cable and the
other being fixed to the throttle lever. Normally, the cable and
throttle lever move in unison and therefore there is no relative
movement between the switch contacts. However, when the throttle
cable fails to return the gas flow control valve towards a closed
position as the throttle lever is moved towards its closed
position, the switch contacts move relative to each other and
either open or close the switch. For the specific illustrated
embodiment the switch is normally open. Should the cable stick,
upon return of the throttle towards its closed position, cable and
throttle lever movement are no longer in unison. Instead, the
throttle lever moves relative to the stuck cable until the cable
contact and the lever contact close to ground the engine ignition
circuit.
In my copending application, a safety throttle is disclosed which
is particularly well suited for a number of different throttles,
including certain types of those throttles commonly referred to as
"twist-grip" throttles. Certain twist-grip throttles, however, are
mounted by means of a collar. The throttle cable passes through a
passageway in the collar and is fixedly secured to the throttle
lever, i.e., to the hand grip. These collar mounted throttles
permit only very limited relative movement between a stuck cable
and the throttle lever. Such a collar mounted type throttle is thus
more subject to inadvertent activation of a relative-movement
safety switch as disclosed in my copending application than a
throttle permitting a relatively large relative movement between
the cable and throttle lever.
The collar mounted throttle also has exposed safety switch contacts
so that they are either subject to icing or corrosion by the
elements or, alternatively, requires a bulky housing for enclosing
the switch contacts.
Accordingly, it is an object of the present invention to provide a
safety throttle, the operation of which is independent of relative
movement between a throttle cable and throttle lever which normally
move in unison.
Another object of the present invention is to provide a collar
mounted twist-grip safety throttle in which the safety throttle
switch components are an integral part of the collar and thus are
protected from icing and corrosion by the elements.
Yet another object of the present invention is to provide a simple
and reliable safety throttle which includes a twist-grip throttle
lever for an internal combustion engine and which grounds the
ignition of the engine controlled by the throttle in the event the
linkage cable sticks holding the gas flow control valve of the
engine carburetor in an open position when an attempt is made to
throttle down to an idle position.
It is a further object of the present invention to provide a safety
throttle wherein the linkage cable provides an electrical ground
contact and the safety switch is an electrical contact coupled to
the ignition whereby the ignition is electrically grounded whenever
the cable comes into contact with said electrical contact.
It is still another object of the present invention to provide a
safety switch on a twist-grip throttle lever wherein both automatic
and manual grounding of said ignition is accomplished.
BRIEF DESCRIPTION OF INVENTION
Briefly, the invention comprises the addition of safety switch
control means to a throttle in which a throttle cable normally
moves reciprocably in a passageway of the throttle. Abnormal
movement of the cable, such as is caused by sticking of the cable
in its sheath, distorts the cable in the passageway causing the
cable to strike the safety switch control means, which control
means controls an ignition circuit safety switch in response to
such a striking to shut off or otherwise disable the engine
controlled by the throttle.
Conveniently, the safety switch control means may be merely an
electrical contact accessible from the passageway but disposed out
of contact with the cable for normal reciprocal cable movement. The
cable and said electrical contact comprise the contacts of a
normally open switch. Distortion of the cable in the passageway
causing the cable to strike the contact, closes the switch to
complete a circuit for grounding an engine ignition circuit.
According to a preferred embodiment, the electrical contact of the
ignition circuit control means is a push-button switch which may be
manually pushed into contact with the cable irrespective of the
cable position or movement to provide for manual shut-off or
disablement of the engine. It will of course be appreciated that
the converse of this embodiment, i.e., a safety switch control
means which is physically moved in response to contact by a cable,
comprises a control switch, the normal state of which is either
normally open or normally closed to provide safety switches
suitable for grounding an ignition circuit and for opening an
ignition circuit path, such as the path between a magneto and spark
plug.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects of the invention will become apparent from the
following description taken in connection with the accompanying
drawings in which:
FIG. 1 is a schematic representation of the novel safety
throttle;
FIG. 2 is a cross-sectional view of the twist-grip throttle lever
and the novel safety switch control means incorporated therein;
and
FIG. 3 is a cross-sectional view of the invention shown in FIG. 2
and taken along the lines 3--3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, there is shown an internal combustion
engine indicated generally by numeral 10. The internal combustion
engine has a flywheel operated magneto (not shown) which functions
to provide high voltage to a spark plug 12 by way of a cable 14.
Engine 10 is also provided with a carburetor 16 having an internal
gas flow control valve (not shown) operated by an elbow linkage 18.
The elbow linkage 18 is normally urged by a spring 20 into a
position in which the flow control valve is closed.
Because the motor and associated linkage 18 are often in an
inconvenient or inaccessible location, means are provided for
adjusting the position of linkage 18, and hence for controlling the
flow of gas into the motor from a remote location. In the prior
art, it is quite conventional to utilize a coaxial cable 22 having
an outer sheath 24 and a central throttle cable 26 passing
therethrough. The outer sheath 24 is secured to the motor or
framework in which the motor is utilized by means of cable clamps
28. The throttle cable 26 is secured at one end to the elbow
linkage 18 and at the other end to a suitable throttle lever, such
that when the throttle lever is operated, the throttle cable 26
moves inside the sheath 28 to operate the elbow linkage 18.
In FIG. 1, the throttle lever is illustrated as a twist-grip handle
grip 30 mounted by a collar 32 to a handle bar 36 so as to be
rotatable as illustrated by the arrow 34. The grip 30 is normally
urged by means of spring 20 at carburetor 16 to a position in which
the gas flow control valve in carburetor 16 is in a closed or
idling position. However, a spring internally located in said grip
30 may be used to return said grip 30 to idle position if desired.
Such a spring is shown in FIGS. 2 and 3.
As can be seen in FIG. 1, a collar 32, which may be conveniently
constructed in halves, attaches grip 30 to handle bar 36 by means
of bolts 38. Collar 32 has an internal annular groove, shown in
detail in FIGS. 2 and 3, which receives a flange on the end of said
grip 30 and enables said grip 30 to turn freely about said handle
bars 36 while being held securely by said collar 32. Throttle cable
26 in sheath 24 enters and passes through a passageway in a
projecting neck 40 on said collar 32 and the end of said cable is
rigidly secured to said grip 30 as will be shown in detail in FIGS.
2 and 3. Thus, when the operator rotates grip 30, the cable 26 is
caused to move thus controlling the gas flow control valve on
carburetor 16.
A push-button switch 42 is mounted on neck 40 of collar 32 such
that an electrical conductor is projected through collar 32 to
within close proximity of said cable 26. Switch 42 includes a
spring 44 neck 40 and a head 46. A conductor 48 is secured to head
46 of switch 42 and is electrically connected to an inner
conductive contact of said switch 42. This inner conductive contact
is electrically insulated from the outer portion of said switch 42
as will be shown in FIGS. 2 and 3.
In FIG. 1, the grounded cable 26 and conductor 48 function as an
ignition circuit safety switch under the control of the push-button
switch 42. As will become more fully apparent upon reading the
following description of FIGS. 2 and 3, the inner electrical
contact of push-button switch 42 is operative to effectively close
the safety switch in response to distortion of the cable 26 causing
the cable to strike the contact and thereby complete an electrical
circuit between spark plug 12 and ground.
FIG. 2 is a cross-sectional view of the grip 30, collar 32, handle
bar 36 and switch 42. In this FIGURE, like numbers will be used for
identical components in FIG. 1 for ease of identification. Grip 30
is attached to handle bar 36 by means of collar 32 which is
comprised of two halves. Only one half of the collar is shown in
FIG. 2. Bolts 38 (shown in FIG. 1) which pass through holes 50 hold
the two halves together. It will be seen that collar 32 has an
annular internal groove 52 which receives a flange 54 on the end of
grip 30. Grip 30 rotates about handle bar 36 but is restrained
against movement axially along handle bar 36 by collar 32. Detent
56 on flange 54 rigidly secures the end of throttle cable 26 thus
providing movement of the cable 26 in unison with movement
(rotation) of the grip 30 to control the gas flow control valve
whenever grip 30 is rotated by the operator.
Push-button switch 42 is mounted on said collar 32 such that it
projects through collar 32 to within close proximity to cable 26.
If the operator desires to manually stop the engine, he depresses
pushbutton switch 42 against spring 44 until the inner conductive
contact, shown as 58, comes into physical contact with cable 26.
Since cable 26 is at ground potential and since conductor 48 is
coupled to the spark plug and to inner conductive contact 58, the
spark plug is grounded and the engine stops. It should be noted
that the inner conductive contact 58 of switch 42 is electrically
insulated from the collar 32 by means of an insulator 60. Feet 62
of the lower portion of said switch 42 secure it to collar 32 and
prevent the switch 42 from coming out of the collar 32. A spring 64
which may be in the form of a semi-coiled leaf spring biases grip
30 to its idle position; the spring 20 shown in FIG. 1 assists in
holding grip 30 in this position. So long as the cable 26 is
properly lubricated and in good working order, the spring 20 has
sufficient force to move the gas flow control valve to the closed
position and move cable 26 to the left when the operator returns
grip 30 toward its idle position. However, should the cable 26
become frayed or for any other reason bind within the sheath 25 in
a position holding the gas flow control valve on carburetor 16
open, when the 30 is 30is returned toward its idle position, cable
26, which is at ground potential, will tend to distort (as
indicated by the dashed line in FIG. 3) since it cannot move in the
sheath 24 to strike inner conductive contact 58 of switch 42. This
will complete the electrical circuit from ground (the cable 26)
through conductor 48 to ground spark plug 12 and shut off the
engine.
FIG. 3 is a sectional view of the view of FIG. 2 taken along lines
3--3. Here it can be seen that collar 32 is comprised of two
halves, 66 and 68, the two halves meeting at points indicated as 70
and 72. It can also be seen that inner conductive contact 58 of
switch 42 is in such close proximity to cable 26 that should cable
26 be prevented from moving in sheath 24, if grip 30 moves towards
its closed position (counter-clockwise in FIG. 3) detent 54 will
move cable end 56 to the left thus bowing cable 26 as indicated by
dotted line 74 causing it to make electrical contact with the inner
conductive contact 58 of switch 42 thus stopping the engine by
grounding theignition circuit. the ignition
It can thus be seen that the present invention provides a safety
throttle through a minor modification of the existing twist-grip
throttle, the modification of the illustrated preferred embodiment
providing both an automatic engine shut off if the throttle control
cable sticks or manual shut off if so desired by the operator.
The foregoing description and drawings clearly disclose preferred
embodiments of the invention, but it will be understood that this
disclosure is merely illustrative and that changes may be made
within the scope of the appended claims.
* * * * *