FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
"EXCELLED POTENTIOMETER LOCKING
ARRANGEMENT OF ELECTROMECHANICAL
HEAD LAMP LEVELING MOTOR"
MINDA INDUSTRIES LIMITED of Village Nawada Fatehpur, P.O. Sikanderpur Badda, Distt. Gurgaon, Haryana - 122004
The following specification particularly describes the invention and the manner in which it is to be performed.

"EXCELLED POTENTIOMETER LOCKING ARRANGEMENT OF ELECTROMECHANICAL HEAD LAMP LEVELING MOTOR"
Field of Invention
The present invention relates to a head lamp leveling apparatus of an automobile, particularly, the present invention relates to potentiometer locking mechanism of electromechanical head lamp leveling apparatus.
Background of invention
A head lamp leveling apparatus also known as head lamp leveling motor is used in the head lamps of automobiles for controlling the variation in required angle of head lamp beam with respect to the road surface under different loading condition of the vehicle. A component as potentiometer is required for feedback system from mechanical parts to electronic circuit. Similar kind of potentiometer locking arrangement had been disclosed in the European patent number EP0881120A2. Main drawback of the above system is that slider of potentiometer can be damaged at any point of time and system can loose it's prime function. It is due to the fact that material of the slider is thermoplastic and it always remains in friction with other rubbing parts as slider is sandwiched between gear top land and locking part. Another drawback of the above said system is that assembly of the parts is complex and time consuming because there are three numbers of parts involved in the above said system and these parts to be assembled separately and further it is to be assembled in the main assembly.
Objects of present invention:
The main object of present invention is to provide a head lamp leveling apparatus. Another object of the present invention is to provide a head lamp leveling apparatus with improved potentiometer locking arrangement.
Still another object of the present invention is to provide an improved potentiometer locking arrangement for a head lamp leveling apparatus in order to minimize the risk of damaging the potentiometer's slider.

Yet another object of the present invention is to provide an economic and cost effective head lamp leveling apparatus which withdraws lesser current and more vibration proof. Summary of invention:
The invention provides a head lamp leveling apparatus with a novel potentiometer locking arrangement. In the present head lamp leveling apparatus, shaft holder is provided with a locking means having a circular slot adapted for securing slider of the potentiometer so that the slider does not come in contact of surface of rotating gear of the head lamp leveling apparatus.
Brief Description of the drawings
Figure 1 illustrates isometric view of the potentiometer locking sub-assembly or
mechanism of a head lamp leveling apparatus or motor according to an embodiment of
the present invention.
Figure 2 shows an exploded view of potentiometer locking sub-assembly or mechanism
of a head lamp leveling motor assembly in accordance of an embodiment of the present
invention.
Figure 3 shows a shaft holder of potentiometer locking sub-assembly or mechanism of a
head lamp leveling motor assembly of the present invention according to an embodiment.
Figure 4 shows a sectional view of helical gear of the head lamp leveling apparatus
according to an embodiment of the present invention.
Figure 5 shows a vertical sectional view of the potentiometer locking sub-assembly or
mechanism of a head lamp leveling apparatus according to an embodiment of the present
invention.
Figure 6 illustrates isometric view of sub-assembly of potentiometer locking mechanism,
DC motor and PCB of a head lamp leveling motor assembly in accordance of an
embodiment of the present invention.
Detailed description of the present invention
Accordingly, the present invention provides a head lamp leveling apparatus comprising: a gear being driven by a motor based on feedback signal provided by a potentiometer;

a shaft holder securing a shaft is locked inside hub of the said gear against the relative rotation therewith so that shaft holder and the shaft is axially movable along with axial movement of the gear; characterized in that the shaft holder comprising a locking means for securing slider of the potentiometer so that the axial movement of the shaft holder moves the slider; said locking means is constructed so that the slider does not come in direct contact with surface of the rotating gear.
In an embodiment of the present invention the slider comprises a slider pin and the locking means comprises a circular slot for securing the said slider pin.
In another embodiment of the present invention the locking means comprises a pair of locking arms each of which provided with a cutout opposing each other so as to form the said circular slot for securing the slider pin.
In still another embodiment of the present invention the said locking arms is rigidly attached with flat end of the shaft holder or integrally formed with the said shaft holder.
In yet another embodiment of the present invention the said locking arms extend from the flat end of the shaft holder in zig-zag form aligning with the slider of the potentiometer and secure the slider pin.
In a further embodiment of the present invention the shaft holder comprises plurality of snaps for locking the shaft holder inside the hub of the gear.
In a further more embodiment of the present invention the gear is a helical gear being threadedly secured inside a housing so that rotaional motion of the gear by motor screw or unscrew the said gear with respect to the housing resulting into axial movement of the gear.

In another embodiment of the present invention the shaft holder has at least one flat surface and the housing has at least one corresponding flat surface for axially guiding the said shaft holder being keyed in the housing against the relative rotation therewith.
In still another embodiment of the present invention the shaft holder is provided with plurality of guiding ribs to be clearance fitted with inner diameter of the helical gear.
In yet another embodiment of the present invention the shaft comprises a threaded length to cooperate with corresponding threads provided inside the shaft holder for securing the said shaft with the shaft holder.
In a further embodiment of the present invention the motor is mounted on the printed circuit board (PCB) comprises one or more slots for extending there through one or more terminals for electrical connections.
In a further more embodiment of the present invention the locking arms being made of resinous plastic material so that the circular slot formed by a the cutouts is expandable for receiving the slider pin.
In another embodiment of the present invention the shaft is coupled with a reflector of the headlamp.
The present invention also provides a potentiometer locking arrangement for a headlamp leveling apparatus, said arrangement comprising a locking means rigidly connected with a shaft holder and said locking arm comprising a slot for securing slider of the potentiometer.
In another embodiment of the present invention the shaft holder is locked with a gear which is movable rotabaly and axially with respect to axis of the said gear.

In still another embodiment of the present invention the locking means comprises a pair of locking arms extending from a flat end of the said shaft holder, said arms comprises cutouts opposing each other thereby forming the slot for securing slider pin of the slider of the potentiometer.
In yet another embodiment of the present invention the locking arms extend from the said shaft holder in a zig-zag manner so during axial movement of the shaft holder, the slider pin does not come in contact with surface of the rotating gear.
The following paragraphs describe the present invention with reference to figures 1-6.
Figure 1 shows a sub-assembly of potentiometer locking arrangement of a head lamp leveling apparatus according to an embodiment of the present invention. As shown in figure 1, the head lamp leveling apparatus comprises a metallic shaft (la) which has a spherical ball (lb) attached at one end of the metallic shaft (la). The spherical ball (lb) can be press fitted with a thermoplastic mating coupler of a head lamp housing or reflector (not shown in the figure). With the help of the metallic shaft (la) axial stroke can be transmitted to the head lamp to tilt the head light beam with respect to road surface according to the requirement of the driver. The shaft (la) comprises a threaded length which can be screwed over a thermoplastic shaft holder (2). In other words, the threaded length of the shaft is secured inside the shaft holder (2). The shaft holder (2) is locked inside a blind hole of hub of a thermoplastic helix gear (3) through plural snaps. The helix gear (3) is driven by a gear train of a motor. The helix gear (3) comprises a threaded portion (4) be screwed or unscrewed to the thread provided in a housing (not shown in the figure). As shown in the figure 1, when the helix gear (3) rotates in clockwise or anticlockwise direction, the helix gear (3) starts moving downward along the axis and vice versa. According to the most favorite embodiment of the present invention, the said shaft holder (2) has at least one flat surface (5) which restricts the free rotation and guide the shaft holder (2) in similar mating surface of the of the said housing, in a direction of alignment of potentiometer's slider 7.

Figure 2 shows an exploded view of potentiometer locking sub-assembly or mechanism of a head lamp leveling motor assembly in accordance of an embodiment of the present invention. As shown in figure 2, a circular slot (6) is provided in the said shaft holder 2. In an embodiment of the present invention, the shaft holder is provided with a locking means having a circular slot for securing slider of the potentiometer. The assembly of said thread gear (3) and the shaft holder (2) is movable in upward and downward direction; as can be observed from figures 1 and 2, movement of the thread gear moves the slider (7) of the potentiometer (8) which is hinged with the circular slot of the shaft holder (2) potentiometer. The slider comprises a slider pin (7) which can be secured in the circular slot (6). The potentiometer (8) provides linear resistive feedback signals which are delivered to the other electrical components (such as motor) for further movement of said shaft (1) according to the driver's requirement of tilting the head light beam with respect to road surface.
Figure 2 also shows sequence of assembly of the components of the potentiometer locking arrangement according to an embodiment of present invention. The helix gear (3) is to be screwed in the threads provided inside the housing of the head lamp leveling motor and the shaft holder is pressed and locked with the helix gear (3) through the plurality of snaps provided in the shaft holder. A printed circuit board (PCB) (9) is then assembled to the said housing with two guide bosses of diameters suitable for the entry of through holes (10) and (11) in the PCB (9). In an embodiment of the present invention a double sided PCB can be used. The slider pin (7) is aligned with the circular slot (6) so that the axis of the circular slot passes through the centre of slider pin (7). The slider slides in the potentiometer (8) and reaches to the height of the circular slot (6) with respect to any horizontal plane of the housing. Furthermore, the slider pin rests at the slider's open position (12) and slider's locked position (13) (as shown in figure 3) which is achieved by slight pushing the slider by a thin tool. The said tool can be of any cross-section which is size smaller than the size of through slot of any shape provided in the said PCB for locking the potentiometer slider in the said shaft holder. For this purpose, the locking means comprises two thin arms or locking arms (14) having zig-zag section which are extended and made flexible enough to accommodate the slider according to an

embodiment of the present invention. Whenever the said slider tends to shift from the locked position (13), the thin arms expand outwardly in order to fit the slider in the circular slot and keep the slider to keep in locked position (13) of the said shaft holder. The locking arms (14) possess the least possible thickness so as to provide least possible contact area between said slider and locking arms resulting in enhanced life of the potentiometer's slider and slider pin. This is due to the reduced stress which might have produced in the slider due to misalignment between the slider's axis and the axis of the circular slot (6). The said misalignment could be generated if potentiometer is soldered in slightly tilted position deviating from the normal position.
As can be observed from figures 1-3, locking means comprises pair of locking arms each of which provided with a cutout opposing each other so as to form the said circular slot for securing the slider pin. The said locking arms can be rigidly attached with flat end of the shaft holder or integrally formed with the said shaft holder.
The locking arm (14) is extended in a zig-zag manner so that the slider pin is secured in the circular slot. With this construction, the slider pin does not come in contact with top land surface of the thread gear (3); hence, when the gear rotates and moves upward and downward direction the slider pin does not rub with the rotating gear (3) thereby life of the slider pin increases.
In an embodiment of the present invention, a plurality of guiding ribs (15) are provided on the shaft holder (2) which are to be clearance fitted with inner diameter (16) of the helical gear (3) so that there is no relative tilting/ rotation between the axes of the shaft holder and the helical gear. Thereby, helical gear (3) can be rotated, screwed or unscrewed over the threads of said housing smoothly and effectively. Moreover, for assembling the shaft holder (2) to the helical gear (3), a flat bottom face of end face (17) is mate assembled to a flat face (18) provided inside thread or helical gears (3, 4) (as shown in figure 3 and 4). A plurality of snap lock faces (19) are provided inside the thread gear (3, 4) which are mate assembled with top face of circular rib or snaps of the shaft holder in clearance fit. All mate faces of shaft holder and the thread gear (3, 4) are

assembled in accordance with some lubricating agent means over the positions (20), (21) and (22) as shown in figure-5 which allows rotation of the said helical gear over the said shaft holder smoothly and with the least friction for enhancing load carrying capacity of the mechanism.
Figure 6 illustrates isometric view of sub-assembly of potentiometer locking mechanism, DC motor and PCB of a head lamp leveling motor assembly. Figure 6 illustrates an embodiment of present invention, which relates to the robustness and constraints of the assembly of internal parts, leads to the effective and relatively more vibration free system resulting in reduced play among the PCB and other internal parts. Hence, relatively lesser current is withdrawn by the above head lamp leveling motor with the present system/apparatus. The PCB is seated/placed on flat top faces of two ribs in the said housing, through circular slots (23) and (24) forming surface contact. Two terminals (24) of a DC motor (25) which is fully constrained in the said housing, have been aligned to the centre of rectangular slots (26), as shown in figure 2, and soldered with the said PCB for fully constraining it in the said housing. In an embodiment of the present invention terminals can be soldered with the PCB and the motor can be directly soldered on the PCB.
The main advantage of the present invention is that the potentiometer locking arrangement of the present invention is extremely simple to manufacture and assemble. The head lamp leveling motor assembly of the present invention requires less number of parts as compared with the existing potentiometer locking arrangement thereby making the system of the present invention very economic and cost effective. Another advantage of the present invention is that as there is no rubbing or friction among the shaft holder locking arms, potentiometer's slider and top face of helical gear which enhances life of the potentiometer locking arrangement. The head lamp leveling motor assembly of the present invention is vibration proof resulting in reduced the current level withdrawn in comparison to the existing head lamp leveling motors.

The present invention is described with reference to the figures and specific embodiments; this description is not meant to be construed in a limiting sense. Various alternate embodiments of the invention will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such alternative embodiments form part of the present invention.

We Claim:
1. A head lamp leveling apparatus comprising:
a gear being driven by a motor based on feedback signal provided by a potentiometer; a shaft holder securing a shaft is locked inside hub of the said gear against the relative rotation therewith so that shaft holder and the shaft is axially movable along with axial movement of the gear; characterized in that the shaft holder comprising a locking means for securing slider of the potentiometer so that the axial movement of the shaft holder moves the slider; said locking means is constructed so that the slider does not come in direct contact with surface of the rotating gear.
2. A head lamp leveling apparatus as claimed in claim 1, wherein the slider comprises a slider pin and the locking means comprises a circular slot for securing the said slider pin.
3. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the locking means comprises a pair of locking arms each of which provided with a cutout opposing each other so as to form the said circular slot for securing the slider pin.
4. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the said locking arms is rigidly attached with flat end of the shaft holder or integrally formed with the said shaft holder.
5. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the said locking arms extend from the flat end of the shaft holder in zig-zag form aligning with the slider of the potentiometer and secure the slider pin.
6. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the shaft holder comprises plurality of snaps for locking the shaft holder inside the hub of the gear.

7. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the gear is a helical gear being threadedly secured inside a housing so that rotaional motion of the gear by motor screw or unscrew the said gear with respect to the housing resulting into axial movement of the gear.
8. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the shaft holder has at least one flat surface and the housing has at least one corresponding flat surface for axially guiding the said shaft holder being keyed in the housing against the relative rotation therewith.
9. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the shaft holder is provided with plurality of guiding ribs to be clearance fitted with inner diameter of the helical gear.
10. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the shaft comprises a threaded length to cooperate with corresponding threads provided inside the shaft holder for securing the said shaft with the shaft holder.
11. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the motor is mounted on the printed circuit board (PCB) comprises one or more slots for extending there through one or more terminals for electrical connections.
12. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the locking arms being made of resinous plastic material so that the circular slot formed by a the cutouts is expandable for receiving the slider pin.
13. A head lamp leveling apparatus as claimed in any of the preceding claims, wherein the shaft is coupled with a reflector of the headlamp.

14. A potentiometer locking arrangement for a headlamp leveling apparatus, said arrangement comprising a locking means rigidly connected with a shaft holder and said locking arm comprising a slot for securing slider of the potentiometer.
15. A potentiometer locking arrangement as claimed in claim 14, wherein the shaft holder is locked with a gear which is movable rotabaly and axially with respect to axis of the said gear.
16. A potentiometer locking arrangement as claimed in claims 14-15, wherein the locking means comprises a pair of locking arms extending from a flat end of the said shaft holder, said arms comprises cutouts opposing each other thereby forming the slot for securing slider pin of the slider of the potentiometer.
17. A potentiometer locking arrangement as claimed in claims 14-15, wherein the locking arms extend from the said shaft holder in a zig-zag manner so during axial movement of the shaft holder, the slider pin does not come in contact with surface of the rotating gear.
18. A head lamp leveling apparatus and a potentiometer locking arrangement for a headlamp leveling apparatus substantially as herein described with reference to the accompanying drawings.