FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICA TION
(See section 10, rule 13)
1. Title of the invention
AN IDLE MECHANISM
2. Applicant(s)
Name Nationality Address
EXCEL CONTROLINKAGE PVT. LTD INDIA W-68 MIDC INDUSTRIAL AREA, HINGNA ROAD,
NAG PUR -440016
3. Preamble to the description
COMPLETE SPECIFICA TION
The following specification particularly describes the invention and the manner in which it is
to be performed.

The disclosure relates to an idle mechanism for an engine. More particularly the disclosure relates to an automatic idle mechanism for an engine of a construction machine.
BACKGROUND
Construction or work machines include tractors, excavators, backhoes and other earth moving or mobile construction equipment. Such machines typically use hydraulic cylinders to control and operate a tool. Hydraulic systems may further be deployed to move the machine as well as rotate the machine body relative its undercarriage, if necessary.
When such construction machines are operating, the throttle of the engine is set at a relatively high level to provide the necessary power for the machine. However, such machines are often in a condition or on standby when no hydraulic function is operated. Typically, such machines are on idle between two tasks or when waiting for another task to complete. When the machines are not being used momentarily or for longer periods of time, the engine is often allowed to continue at the high throttle position consuming a substantial amount of fuel as well as causing undue wear.
Many solutions have been proposed to provide some automatic change in throttle position between a high throttle and a low throttle position when the machine is sensed to be in an idle condition. Such system may be electronic and therefore expensive or may be mechanical/electromechanical and often exceedingly complicated. One such system utilizes electronic controllers and sensors to determine when the machine is in idle and utilizes a hydraulic cylinder connected to the throttle and the lever for regulating fuel to the engine. When hydraulic load is sensed the mechanism returns the engine to a high idle position. However, while electronic based systems are costly to implement, known idle mechanisms typically require some level

of operator input in returning the engine to a high idle position, require operator force to move the throttle against a spring force or require operator force to hold throttle at a given position.
Figure 1 illustrates one such idle mechanism available in the art. A hand throttle lever is connected to the idle mechanism. A control rod links the idle mechanism to an engine throttle. The throttle controls fuel input to the engine (not shown) and consequently the engine RPM. The idle mechanism includes a pressure sensor (not shown) for sensing hydraulic load that actuates a solenoid valve. The solenoid valve is connected to a hydraulic cylinder actuating a lever to which the connecting rod for the throttle and the throttle arc connected. Movement of the lever, either in response to the solenoid valve or the throttle lever moves the throttle between the low idle and the high idle position. Movements of the throttle lever between the low idle and the high idle position result in corresponding movement of the throttle between the low idle and the high idle position. As the connections from the idle mechanism, particularly the connection to the throttle is through a solid rod linkage mechanism, the idle mechanism has to be positioned very close to the engine to prevent the linkage from becoming very complicated with several bends and links. Placing the idle mechanism proximate the engine however results in the following disadvantages:
a) Special mountings have to be created on the engine block to mount the idle mechanism;
b) Since the mechanism has to be very close to the engine and on account of the space restrictions on modern engines, the mounting becomes very complicated and requires a very skilled operator to mount it in the restricted space. Consequentially, maintenance or repairs become very cumbersome and time consuming as well.

c) Proximity to the engine results in the idle mechanism becoming very hot. Besides adversely affecting the life of the idle mechanism, any maintenance would require a cooling off period of several minutes to several hours.
d) Load incident on the cylinder by the mechanism (spring force) is not co-axial with the cylinder resulting in reduced life and seal failure of the hydraulic cylinder.
US 44740883 describe a fuel control modulation system for automatic transmissions that aims to avoid loads during shifting. In addition to the different purpose of the mechanism, the system is an electronic system requiring an electronic logic controller. Moreover, when the operator moves the throttle lever, he has to overcome the throttle load as well as the additional spring load of a coil spring. A torsional spring is also provided that is weaker than the coil spring to minimize the changes in load that the operator feels. However, there remains an additional load of the coil spring that the operator has to work against at all times. With use, this load increases significantly causing enhanced operator discomfort.
US 4643146 describe an apparatus for controlling the rotary speed of a diesel engine for a hydraulic excavator. The apparatus requires operator to overcome both the throttle load as well as the load of the entire hydraulic cylinder when moving the throttle to a high power position. When moving the throttle to a low idle position, the operator has to overcome a spring load. This additional load causes operator discomfort and tends to increase with use. Moreover, the apparatus permits the throttle to be set in only the fully open position,
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Figure 1 is a schematic diagram of an idle mechanism available in the art. Figure 2 is a schematic diagram of an idle mechanism in accordance with an embodiment of the invention.

Figure 3 is an isometric view of an idle mechanism in accordance with an embodiment of the invention.
Figure 4 is an isometric view of an idle mechanism in accordance with an alternative embodiment of the invention.
SUMMARY
An idle mechanism for regulating a throttle of an engine having a throttle lever is disclosed. The idle mechanism comprises of a housing and an actuating lever that is pivotally mounted on the housing and connected at one end to the throttle such that movement of the actuating lever from a first position to a second position moves the throttle between a low idle mode and a high idle mode. The actuating lever is connected at the other end to the throttle lever. The idle mechanism further comprises of a hydraulic cylinder connected to the actuating lever and is configured to move the actuating lever between the first position and the second position wherein the hydraulic cylinder is pivotally mounted on the housing.
DETAILED DESCRIPTION
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof. Throughout the patent specification, a convention employed is that in the appended drawings, like numerals denote like components.
Reference throughout this specification to "one embodiment" "an embodiment" or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in one embodiment", "in an embodiment" and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
Referring to Figures 2 and 3, an idle mechanism in accordance with an embodiment is disclosed. A first mechanical control cable 100 connects the idle mechanism 200 to a throttle lever (not shown). A second mechanical control cable 300 connects the idle mechanism 200 to an engine throttle (not shown). The throttle (not shown) controls fuel input to the engine (not shown) and consequently the engine RPM. The idle mechanism 200 includes a pressure sensor 400 for sensing engine load that actuates a solenoid valve 202. The solenoid valve 202 is connected to a hydraulic cylinder 204 that moves an actuating lever 206 to which the cables from the throttle (not shown) and the throttle lever (not shown) are connected. The hydraulic cylinder 204 and the solenoid valve 202 are rigidly mounted on a housing 210 of the idle mechanism 200. A resilient member such as spring 208 is provided between the actuating lever 206 and the first mechanical control cable 100. The movement of the actuating lever 206 in response to throttle lever movement to low idle does not extend the spring 208. However, where provisions to lock the throttle at a position are

provided, movement of the actuating lever 206 to push the throttle to a low idle position, in response to the solenoid valve 202. results in the spring 208 being extended without corresponding movement of the throttle lever. When the pressure sensor 400 subsequently detects load in the hydraulic circuit, it causes the solenoid valve 202 to stop flow to the hydraulic cylinder 204. The spring 208 force causes the actuating lever 206 to return to the high idle position resulting in the throttle moving to the high idle position. Movement of the actuating lever 206, either in response to the solenoid valve 202 or the throttle lever moves the throttle between the low idle and the high idle position.
Still referring to Figures 2 and 3, during machine start up both the throttle (not shown) as well as the throttle lever (not shown) is set to low idle. For machine operation, the throttle is moved to high idle resulting in movement of the throttle to the high idle position. When the pressure sensor 400 detects no hydraulic load an input is given to the solenoid valve 202 that directs hydraulic flow to the hydraulic cylinder 204. The hydraulic cylinder 204 moves the idle mechanism 200 to the low idle position and correspondingly the throttle (not shown) moves to the low idle position through movement of the second mechanical control cable 300. As soon as the operator actuates any hydraulic operation, the pressure sensor 400 detects increase in hydraulic load and through the solenoid valve 202, the hydraulic cylinder 204 moves to the high idle position causing the throttle (not shown) to move back to the high idle position.
Referring next to Figure 4, an idle mechanism in accordance with an alternate embodiment is disclosed. In the embodiment disclosed in Figure 3, when the spring 208 is extended it causes a cross load on the hydraulic cylinder 204. This cross load is on account of the spring axis and the hydraulic cylinder axis being parallel but some

distance apart. The cross load may effect the hydraulic cylinder 204 seal life. To overcome this, in the embodiment of Figure 4. the hydraulic cylinder 204 is mounted with a ball and socket joint 500 to the idle mechanism housing 210. The ball and socket joint 500 overcomes most if not the entire cross load incident on the hydraulic cylinder 204 on account of the extended spring 208. The provision of the ball and socket 500 significantly enhances the life of the hydraulic cylinder 204 and that of the idle mechanism 200.
In accordance with an embodiment, the idle mechanism 200 is provided with a delay timer that actuates the solenoid valve 202 for moving the throttle (not shown) to the low idle position only after a pre-determined time period has lapsed. The delay timer may be set to a few seconds or to a few minutes. The delay timer prevents the engine from unnecessary oscillations between low idle and high idle positions.
In accordance with an embodiment, the throttle is a positive lock throttle that allows the throttle to be locked at a certain position. A spring-loaded pin that locks into a slot may achieve the throttle locking. A release button provided on the throttle may release the throttle lock. The positive lock throttle would not move in response to the movement of the throttle to the low idle position when actuated by the actuating lever 204.
While example embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention as described in the claims.

SPECIFIC EMBODIMENTS ARE DESCRIBED BELOW
An idle mechanism for regulating a throttle of an engine having a throttle lever, the idle mechanism comprising a housing, an actuating lever pivotally mounted on the housing and connected at one end to the throttle such that movement of the actuating lever from a first position to a second position moves the throttle between a low idle mode and a high idle mode, the actuating lever connected at the other end to the throttle lever, and a hydraulic cylinder connected to the actuating lever and configured to move the actuating lever between the first position and the second position wherein the hydraulic cylinder is pivotally mounted on the housing.
Such idle mechanism(s), wherein the hydraulic cylinder is pivotally mounted on the housing by a ball and socket assembly.
Such idle mechanism(s), wherein a resilient member is placed between the actuating lever and the throttle lever.
Such idle mechanism(s), wherein the resilient member is positioned parallel to the hydraulic cylinder.
Such idle mechanism(s), wherein the actuating lever is connected to the throttle lever by a control cable.
Such idle mechanism(s), further comprising a sensor for determining the load on the engine and instructing the idle mechanism to move the engine between a low idle mode and a high idle mode.
Such idle mechanism(s), further comprising a solenoid configured to receive instructions from the sensor and to instruct the hydraulic cylinder to actuate the actuating lever.
Such idle mechanism(s), further comprising a control cable for connecting the actuating lever to the throttle.

INDUSTRIAL APPLICABILITY
The idle mechanism is essentially an electro-mechanical system not requiring any electronic components and can be fit on most existing vehicles, especially older construction vehicles.
The idle mechanism disclosed provides for a modular system that can be mounted at any convenient location and does not necessarily have to be placed proximate the engine. As the idle mechanism does not have to be placed close to the engine, problems relating to heat, dust, and excessive vibrations are overcome. Moreover, the modular design enables the idle mechanism to be mounted on a plurality of vehicles without the need of special mounts for each vehicle. The idle mechanism uses the existing cable/link mounting bracket provided obviating the need for any changes to the engine block. The modular system reduces time and eases both installation and maintenance.
The idle mechanism with the hydraulic cylinder mounted to the mechanism housing by a ball and socket joint further enhances the life of the mechanism and prevents premature failure of the hydraulic cylinder.

WE CLAIM:
1. An idle mechanism for regulating a throttle of an engine having a throttle lever, the idle mechanism comprising: a housing;
an actuating lever pivotally mounted on the housing and connected at one end to the throttle such that movement of the actuating lever from a first position to a second position moves the throttle between a low idle mode and a high idle mode; the actuating lever connected at the other end to the throttle lever, and
a hydraulic cylinder connected to the actuating lever and configured to move the actuating lever between the first position and the second position; wherein the hydraulic cylinder is pivotally mounted on the housing.
2. An idle mechanism as claimed in claim I wherein the hydraulic cylinder is pivotally mounted on the housing by a ball and socket assembly.
3. An idle mechanism as claimed in claim 1 wherein a resilient member is placed between the actuating lever and the throttle lever.
4. An idle mechanism as claimed in claim 3 wherein the resilient member is positioned parallel to the hydraulic cylinder.
5. An idle mechanism as claimed in claim 1 wherein the actuating lever is connected to the throttle lever by a control cable.

6. An idle mechanism as claimed in claim 1 further comprising a sensor for determining the load on the engine and instructing the idle mechanism to move the engine between a low idle mode and a high idle mode.
7. An idle mechanism as claimed in claim 6 further comprising a solenoid configured to receive instructions from the sensor and to instruct the hydraulic cylinder to actuate the actuating lever.
8. An idle mechanism as claimed in claim 1 further comprising a control cable for connecting the actuating lever to the throttle.
9. An idle mechanism for regulating a throttle of an engine having a throttle lever substantially as herein described with reference to and as illustrated in the accompanying drawings.