AN INSTRUMENT CLUSTER AND METHODS THEREOF FIELD OF THE INVENTION

The present invention relates to an instrument cluster, more particularly relates to an improved instrument cluster having a Printed Circuit Board (PCB) which holds the pointer drive source and an illumination source of pointer. The instrument finds its potential application in automobile industry.

BACKGROUND OF THE INVENTION AND PRIOR ARTS

The instrument clusters mainly comprised of pointers to indicate the speed or RPM of an engine and fuel level on an index plate/dial. Normally the pointer moves with respect to dial center from position '0' to maximum position of the dial. During the pointer rotation, pointer may produce shadow on the dial. Further the shadow may lead to poor aesthetic look and may also disturb the user.

Figure 1 provides for lαiown art of pointer indication method which contains the following components for indicating speed or RPM of the vehicles

• pointer (11)

• PCB bottom and top (5 and 500)

• stepper motor/drive source (7)

• indication panel (100)

• indication plate (200)

• index parts (201)

• light source for- illuminating the indication panel (100), and

• frame (300)

The limitations in the existing method of pointer indication are;

• The product construction requires at least two PCB (Top and Bottom), wherein the bottom PCB is for holding stepper motor (2) and the top PCB is for light source assembly (Light Emitting Diode),

• New connector is also required to connect said two PCB's.

• Geometry of the pointer leads to difficulty in assembling the PCB assembly into the instrument cluster,

• An additional frame is used for holding the two each other indication panel, indication plate and the light source,

• The product construction requires more spaces for accommodating the both electronics and mechanical components. This is not suitable for very compact design of instrument clusters,

• Additional component No 3 is used for pointer illumination,

• Additional component No 4 is used for holding the PCB, and

• Geometry of the pointer may produce warp.

The aforesaid disadvantages of the related art in-turn increase the cost and require more space of the instrument cluster.

OBJECTS OF THE INVENTION

The principal object of the invention is to develop an instrument cluster having one PCB.

Still another object of the instant invention is to provide for a method of operating the instrument cluster.

Yet another object of the instant invention is to provide for a method of assembling of the instrument cluster.

STATEMENT OF THE INVENTION

Accordingly, the instant invention provides for an instrument cluster comprising; Printed Circuit Board [PCB (I)] assembly having a predetermined shape comprising a drive source connecting to the PCB (1) and is mounted at predetermined location for driving a pointer, a light guide above the PCB (1) comprising a light source (6a) at predetermined location and a reflector (3) mounted above the light source (6a) , a pointer characterized into a bottom pointer (4) and a top pointer (5), wherein said bottom pointer (4) is connecting the drive source and said top pointer (5) is connecting to the bottom pointer (4), to illuminate the dial (7), and case assembly (13) having a predetermined shape for

supporting the PCB assembly, the instant invention also provides for a method of operating instrument cluster, said method comprising acts of; rotating shaft of drive source to rotate pointer connected to the drive source, illuminating the pointer by a light source mounted onto Printed Circuit Board [PCB (I)] for dial (7) indication, and also provides for a method of assembling an instrument cluster, said method comprising acts of assembling of Printed Circuit Board [PCB (I)] comprising acts of connecting pointer drive source to Printed Circuit Board [PCB (I)] in a predetermined manner, mounting a light guide (6) at top of the PCB (1), connecting base pointer with the drive source, connecting top pointer (5) with the bottom pointer (4), wherein said pointer illuminates dial (7) having predetermined graduations for the instrument cluster and mounting said PCB assembly with a case assembly (13) for supporting the PCB assembly.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, in which

Figures 1 and 2: shows existing pointer indication method.

Figures 3 and 4: shows proposed pointer indication method in instrument cluster for automobile applications.

Figure 5 shows layout of the Instrument cluster

Figure 6a: shows the front view of the assembly printed circuit board (PCB) having the diffuser sheet (14).

Figure 6b: shows the cross sectional view of the assembly printed circuit board (PCB) having the diffuser sheet (14).

DETAILED DESCRIPTION OF THE INVENTION

The present invention is in relation to an instrument cluster comprising; Printed Circuit Board (PCB) assembly having a predetermined shape comprising a drive source connecting to the PCB (1) and is mounted at predetermined location for driving a pointer, a light guide (6) above the PCB (1) comprising a light source (6a) at predetermined location and a reflector (3) mounted above the light source (6a), a pointer characterized

into a bottom pointer (4) and a top pointer (5), wherein said bottom pointer (4) is connecting the drive source and said top pointer (5) is connecting to the bottom pointer (4), to illuminate the dial (J), and case assembly (13) having a predetermined shape for supporting the PCB assembly.

In still another embodiment of the present invention the PCB assembly is having predetermined geometric shape, preferably flat.

In yet another embodiment of the present invention the drive source is preferably a stepper motor (2) which is mounted below the PCB assembly.

In still another embodiment of the present invention said stepper motor (2) is mounted in such a way that, stem of the stepper motor (2) faces towards bottom side of the PCB (1) and is pressed from the bottom side of the PCB (1).

In still another embodiment of the present invention the light source (6a) is preferably a Liquid Crystal Display (LCD) and is mounted at the periphery.

In still another embodiment of the present invention the LCD is assembled with a diffuser sheet (14) to diffuse the light all around the LCD surface evenly.

In still another embodiment of the present invention said light guide (6) comprises a warning compartment (10) to indicate the warning signals.

In still another embodiment of the present invention said case assembly comprises of a grommet (11) at its peripheral end to prevent entry of dust and water inside the instrument cluster.

In still another embodiment of the present invention said bottom pointer (4) and top pointer (5) are connected using snap fit.

In still another embodiment of the present invention said dial (7) and diffuser sheet (14) are assembled to LCD holder using screws and guide pinch of the light guide.

In still another embodiment of the present invention the bottom pointer (4) is connected with a counter weight (12) at its other end to balance with respect to its rotating axis.

In still another embodiment of the present invention the case assembly (13) is connected with a PCB assembly by using overhanging support element along with screw and guiding pinch.

In still another embodiment of the present invention said instrument cluster is attached with symbol sheet at warning compartment (10) to glow warning symbols in color code indication.

In still another embodiment of the present invention said instrument cluster is attached with an aluminum dial (8) to indicate the dial major divisions.

The present invention is in relation to a method of operating instrument cluster, said method comprising acts of; rotating shaft of drive source to rotate pointer connected to the drive source, illuminating the pointer by a light source (6a) mounted onto Printed Circuit Board [PCB (I)] for dial (7) indication.

In still another embodiment of the present invention said rotation of pointer indicates the reading of speed/RPM of an engine.

In still another embodiment of the present invention said illuminating of the pointer is carried-out by light source (6a) of Liquid Crystal Display and by a reflector (3).

In still another embodiment of the present invention said pointer is rotated at periphery of the dial (7).

In still another embodiment of the present invention said pointer picks the light from reflector (3) all around its sweep angle.

The present invention is in relation to a method of assembling an instrument cluster, said method comprising acts of assembling of Printed Circuit Board [PCB (I)] comprising acts of connecting pointer drive source to Printed Circuit Board [PCB (I)] in a

predetermined manner, mounting a light guide (6) at top of the PCB (1), connecting base pointer with the drive source, connecting top pointer (5) with the base pointer (4), wherein said pointer illuminates dial (7) having predetermined graduations for the instrument cluster and mounting said PCB assembly with a case assembly (13) for supporting the PCB assembly.

The pointers are mainly used in instrument cluster to indicate the speed or RPM of an Engine and Fuel level on an index plate/ dial. Normally the pointer moves from 0 position to maximum position with respect to dial center. During the Pointer rotation, pointer may produce some shadow on the dial. This shadow produces poor aesthetic and disturbs the rider. But in case of the instant invention the pointer moves on the periphery of the index plate/dial with respect to dial center to overcome the problem of shadow on the dial.

Referring to Figures 3 to 5, in Assembly PCB the front mount stepper motor (2) assembled in bottom side of the PCB (1) by using solder process. The PCB (1) designed with pigtail wiring harness along with Grommet (11) and the grommet (11) is assembled with outer case during the final assembly to arrest the water and dust to the instrument cluster. Also the assembly PCB having the light guide and the same mounted in PCB (1) by using screw along with two guide pinches.

Followed by the Light guide, the Liquid Crystal Display (LCD) is assembled along with diffuser sheet (14) (as shown in figure 6a and figure 6b) to diffuse the light all around the LCD surface evenly. After the assembly of LCD, the outer dial and its diffuser are assembled along with LCD holder by using screws and one guiding pinch.

A warning compartment (10) is also assembled with PCB (1) by using screws and guiding element.

Both the pointer and stepper motor (2) are in PCB Assembly. The stepper motor (2) is assembled in PCB (front mount) in such a way that, stem of the stepper motor (2) focusing towards bottom side of the PCB (1) and the pointer bottom is pressed from the bottom side of the PCB (1). The counter weight (12) attached with bottom pointer by

insert plastic molding process to making the pointer balance with respect to its rotating axis.

Finally in assembly PCB the pointer top is assembled with pointer bottom by using snap fit.

Assembly Case

The outer case has a provision to fit the instrument cluster on a vehicle and also has a provision to assemble with the grommet (11).

The assembly PCB is assembled with outer case by using overhanging support element along with screw and guiding pinch. Then the symbol sheet pasted on the warning compartment (10) to glow the warning symbol along with color code indication. The Spun aluminum dial also mounted/affixed on the symbol sheet with gun profile and spun finish to indicate the dial major divisions.

Finally a glass (9) is assembled along with front ring (by rolling process) to give the better visibility to the driver as well as arrest the water, moisture and dust entry into the instrument cluster.

Advantages in proposed new method:

• The product construction needs only one PCB (1) for holding the pointer drive source and illumination sources of the pointer

• Since the pointer is divided into two parts and geometry of the pointer also ensure that easy assembly process

• Front mount stepper motor (2) used (Upside Down) below the PCB (1) in order to avoid the many no of PCB (1) and easy function of the Pointer

• No frame used

• Even though the size of the instrument cluster is very small and the product construction provides for more spaces for accommodating the both electronics and mechanical components. This is suitable for very compact design instrument cluster.

• Geometry of the pointer does not produce any warp edges in the components and easy for tooling process.

• The pointer designed in such a way that it can pick the light from the Reflector (3) all around its sweep angle.

• No additional components are used to hold PCB (1)

• No additional components are used for the illumination

The above advantages in-turn increases quality and decrease the cost of the product of instrument cluster.

Instant invention involves only one PCB (1) used by using the front mount stepper motor (2) or pointer drive source mounted at bottom side of the PCB (1) by assembling upside down condition.

Both the pointer and stepper motor (2) come in PCB Assembly, the stepper motor (2) assembled in PCB (1) (Front mount) in such a way that stem will focus towards Bottom side of the PCB (1) and the pointer Bottom will be pressed from the Bottom side of the PCB (1). The Counter weight (12) attached with bottom pointer by insert plastic molding process to making the pointer balance with respect to its rotating axis.

The light source for the pointer and dial numerals are also placed on the top side of the same PCB (1) along with its supportive parts.

Steps followed to reduce the components which are used for holding the PCB (1) (Figure

The pointer designed in such a way that it can pick the light from the light source around its sweep angle help of the below indicated components (***).

Component No.4 used for holding the PCB

Only one component used that is reflector (3) to illuminate the pointer all around its Sweep. Where as five components used in the existing method (Figure 2 with *** indication) and no separate component used to hold the PCB.

Referral Numerals

PCB: 1

Stepper motor: 2

Reflector: 3

Bottom pointer: 4

Top Pointer: 5

Light Guide: 6

Lighting Device (LED): 6a

Dial: 7

Al. Dial: 8

Glass: 9

Warning Compartment: 10

Grommet: 11

Counter weight: 12

Case Assembly: 13

Diffuser Sheet: 14

The invention has been described in connection with its preferred embodiments. However, it is not limited thereto. Changes, variations and modifications to the basic design may be made without departing from the inventive concepts in this invention. In addition, these changes, variations and modifications would be obvious to those skilled in the art having the benefit of the foregoing teachings. All such changes, variations and modifications are intended to be within the scope of this invention. The technology of the instant Application explained with the examples should not be construed to limit the scope of the invention.