TECHNICAL FIELD
[0001] The present invention generally relates to automotives and more particularly to control mechanism for controlling motion of windowpanes in automotives.

BACKGROUND OF THE INVENTION
[0002] Use of window regulators in vehicle doors for controlling motion of windowpanes is known. Conventionally  the window regulators have lift arm which is operably coupled to a motor which actuates or controls the movement of lift arm to raise or lower the windowpane. In such an arrangement  relative motion of a sector gear or rack and pinion gear mechanism is converted into linear motion which is translated to the lift arm for controlling motion of the windowpane.
[0003] One limitation associated with the window regulators of the type described above is inability to control the speed of the windowpane in different operations such as raising and lowering. The windowpane when raised to the top position with a uniform speed  hits the window frame at the same speed as it is travelling throughout the operation. This leads to noise and mechanical wear and tear.
[0004] Hence  there is a need for an improved mechanism for controlling the speed of the windowpane during its varied operations.

SUMMARY OF THE INVENTION
[0005] The above-mentioned shortcomings  disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification.
[0006] The object of the present invention is to provide an improved mechanism that reduces the noise generated by the operation of the windowpane.
[0007] In one embodiment  a window regulator mechanism is provided for moving a windowpane. The window regulator mechanism comprises a lift arm which is operably coupled to the windowpane through a window channel. The lift arm comprises an elongated slot with an angulation such that a substantial portion of the elongated slot is parallel to the central axis of the lift arm. The window regulator mechanism further comprises a pin which is configured to move within the elongated slot. Further  the pin is driven by rack and pinion gear mechanism.
[0008] In another embodiment  a window regulator mechanism is provided for moving a windowpane that comprises a rack having an elongated slot with an angular deviation. The window regulator mechanism further comprises a lift arm coupled to the rack  such that the lift arm comprises a pin at one of its end to move within the elongated slot. Further  a substantial portion of the elongated slot is parallel to the central axis of the lift arm.
[0009] Systems and methods of varying scope are described herein. In addition to the aspects and advantages described in this summary  further aspects and advantages will become apparent by reference to the drawings and with reference to the detailed description that follows.

BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG.1 shows a schematic diagram of window regulator mechanism having the illustrated windowpane in top position as described in one embodiment;
[0011] FIG.2 shows a schematic diagram of window regulator mechanism having the illustrated windowpane in bottom position as described in one embodiment;
[0012] FIG.3 and FIG.4 show a schematic diagram of window regulator mechanism having the illustrated windowpane in center position as described in one embodiment;
[0013] FIG.5 shows a schematic diagram of window regulator mechanism having the illustrated elongated slot in the lift arm;
[0014] FIG.6 shows a schematic diagram of window regulator mechanism having the illustrated pin positioned on rack;
[0015] FIG.7 shows a schematic diagram of window regulator mechanism having the illustrated windowpane in top position as described in another embodiment; and
[0016] FIG.8 shows a schematic diagram of window regulator mechanism having the illustrated elongated slot in the rack.
DETAILED DESCRIPTION OF THE INVENTION
[0017] In the following detailed description  reference is made to the accompanying drawings that form a part hereof  and in which is shown by way of illustration specific embodiments  which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments  and it is to be understood that other embodiments may be utilized and that logical  mechanical  electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is  therefore  not to be taken in a limiting sense.
[0018] To substantially eliminate the unwanted vibrations and noise caused while raising a windowpane in a vehicle  a window regulator mechanism is provided with a speed control mechanism. The speed control mechanism includes a pin and an elongated slot having an angulated portion provided within a lift arm. The pin is guided within the elongated slot such that constant velocity of a drive system is converted to variable velocity of the lift arm.
[0019] FIG. 1 and FIG. 2 show a window regulator mechanism configured for moving a windowpane 10 in a vehicle door 12. The windowpane 10 may be moved in the vertical direction from a first position 14 to a second position 16 for example from a top position to a bottom position. Accordingly  the windowpane 10 when moved in a first direction i.e.  from the first position 14 to the second position 16 allows proper ventilation for passengers. Similarly the windowpane 10 when moved in a second direction i.e.  from the second position 16 to the first position 14 prevents dust entering into passenger compartment of the vehicle.
[0020] For facilitating the motion of the windowpane 10  the window regulator mechanism comprises a lift arm 18. The lift arm 18 controls the raising or lowering of the windowpane 10. FIG. 1 and FIG. 2 show the window regulator mechanism operating the windowpane 10 in the first position 14 and the second position 16 respectively. The window regulator mechanism further comprises a drive system configured to initiate and control the motion of the lift arm 18. The first end of the lift arm 20 is operably coupled to the drive system and the second end of the lift arm 22 is configured to support the windowpane 10. Further  the window regulator mechanism comprises a windowpane channel 24 and a windowpane holding clips 26 to support the windowpane 10. The drive system may comprise any driving mechanism configured for inducing motion in the lift arm 18 of the window regulator mechanism.
[0021] One of the examples for the drive system is rack and pinion drive mechanism. The rack and pinion mechanism comprises a rack 28  a pinion gear 30 and a motor 32. Further  the rack 28 comprises a plurality of rack teeth 34. When powered by the motor 32 coupled to the rack 28  the pinion gear 30 travels through the rack teeth 34 to operate the lift arm 18. Further  the window regulator mechanism comprises a base plate 36 operably coupled to the rack 28 and the motor 32. The base plate 36 is assembled to the vehicle door 12 and the lift arm 18 is pivotally coupled to the base plate 36.
[0022] The window regulator mechanism further comprises a first arm 38 and a second arm 40 operatively coupled to the lift arm 18 by a rivet 42. The first arm 38 and the second arm 40 are configured to support the lift arm 18. Further  the first arm 38 is coupled to a fixed channel 44 and the lift arm 18. The second arm 40 is operably coupled to the windowpane channel 24 and the lift arm 18.
[0023] In one embodiment of the window regulator mechanism  the lift arm 18 comprises an elongated slot 46 at the first end of the lift arm 20. The elongated slot 46 provided comprises an angulated portion 48 and a substantial portion of the elongated slot 46 is parallel to the central axis of the lift arm 50. Further  the rack 28 comprises a pin 52 configured to slide within the elongated slot 46 so as to control the motion of the lift arm 18. The pin 52 sliding in the elongated slot 46 during the operation controls the movement of the lift arm 18 that in turn moves the windowpane 10 from the first position 14 to the second position 16 or vice versa.
[0024] FIG. 3 and FIG. 4 show the window regulator mechanism having the windowpane 10 positioned in center position 54. Moving the windowpane 10 from the first position 14 to the second position 16 or vice versa results in a complete cycle of motion of the pin 52 sliding within the elongated slot 46. That is  an execution of a complete cycle of sliding motion of the pin 52 within the elongated slot 46 results in the motion of the windowpane 10 from the first position 14 to the second position 16. Accordingly  during the initial setup  the pin 52 is positioned at the first end of the elongated slot 56 when the windowpane 10 is positioned at the first position 14  subsequently the pin 52 reaches the second end of the elongated slot 58 such that the windowpane 10 reaches the center position 54. Further  the pin 52 slides from the second end of the elongated slot 58 and slides towards the first end of the elongated slot 56 to move the windowpane 10 from the center position 54 to the second position 16. Similarly  the pin 52 sliding within the elongated slot 46 provided in the lift arm 18 completes one cycle to move the windowpane 10 from the second position 16 to the first position 14. This is further explained in conjunction with FIG. 5.
[0025] FIG. 5 shows operation of the window regulator mechanism in detail. As described in the above embodiment  the pin 52 is positioned on the rack 28 so as to facilitate the pin 52 to slide inside the elongated slot 46 to enable the raising and the lowering of the lift arm 18. More specifically  when the motor 32 is powered  the rack 28 is engaged through the pinion gear 30 and the uniform speed of the motor 32 is transferred to the rack 28. The uniform velocity of the rack 28 in turn is transferred to the pin 52 so as to move the pin 52 within in the elongated slot 46. Moving the pin 52 in such a way controls the movement of the lift arm 18.
[0026] As explained in the aforesaid embodiments  the velocity of the rack 28 is uniform due to uniform speed of the motor 32. To substantially eliminate the unwanted vibrations and noise caused while raising the windowpane 10 in the vehicle door 12  the angulated portion 48 of the elongated slot 46 facilitates speed control in the window regular mechanism. The angulated portion 48 provided in the elongated slot 46 reduces the speed of the windowpane 10 prior to the windowpane 10 reaching the first position 14. In the elongated slot 46  the deviation of the angulated portion 48 is provided such that the distance covered by the pin 52 within the deviated portion of the elongated slot 46 increases thereby decreasing the speed of the lift arm 18  which would otherwise be uniform had the deviation not been provided. During the motion of the windowpane 10 towards the first position 14  the pin 52 slides in the angulated portion 48 of the lift arm 18 such that the constant velocity of the rack 28  and the increased distance to be travelled by the pin 52  forces the lift arm 18 to exhibit non-uniform velocity that eventually results in reduced speed of the lift arm 18. Reduction in speed of the lift arm 18 when the pin 52 is sliding in the angulated portion 48  results in the windowpane 10 reaching the first position 14 with lesser speed thereby reducing noise.
[0027] For the arrangement described  depending on the angulation provided in the elongated slot 46 of the lift arm 18  the speed ratio of the rack 28 and the lift arm 18 movement may vary. Alternately  for the arrangement comprising an elongated slot 46 with straight portion the speed ratio of the rack 28 and the lift arm 18 movement is 1:1.
[0028] However  to avoid the variation of the velocity in the lift arm 18 when the windowpane 10 is reaching towards the second position 16  the pin 52 is positioned on the rack 28 such that the distance between the pin 52 and the first end of the rack 60 is less than the distance between the pin 52 and the second end of the rack 62.
[0029] To achieve the aforesaid function  the pin 52 is positioned on the rack 28 as shown in FIG. 6. When the pin 52 starts sliding in the elongated slot 46 to reach the first end of the elongated slot 56 passing through the angulated portion 48  the windowpane 10 moves to reach the second position 16. Due to the location of the pin 52  the rack 28 operates as a stopper in order to stop the pin 52 prior to the onset of sliding in the angulated portion 48 of the elongated slot 46 provided in the lift arm 18. By positioning the pin 18 closer to the first end of the rack 60  speed reduction of the windowpane 10 moving towards the second position 16 is achieved.
[0030] In another embodiment of the window regulator mechanism as shown in FIG.7 and FIG.8  the rack 100 comprises an elongated slot 102 provided along its length having an angulated portion 104 and substantial portion of the elongated slot 102 is parallel to the central axis of the lift arm 110. The lift arm 106 comprises a pin 108 at one of its end to move within the elongated slot 102 provided in the rack 100.
[0031] Although the drawings show the embodiments as used in cross arm window regulator mechanism  the invention can also be used in a single lift arm window regulator having only a single lift arm 18. Further  the invention may not be restricted to having a single elongated slot 46 and a pin 52 to slide within and hence the number of elongated slot 46 in the lift arm 18 and the pin 52 to slide within the elongated slot 46 may not restricted to one.
[0032] The advantage of the invention includes an improved arrangement to reduce noise and provide speed control for the window regulator mechanism.
[0033] This written description uses examples to describe the subject matter herein  including the best mode  and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims  and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims  or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

CLAIMS
WE CLAIM:
1. A window regulator mechanism for moving a windowpane  the window regulator mechanism comprising:
a lift arm operably coupled to the windowpane through a windowpane channel  the lift arm having an elongated slot with an angulation wherein a substantial portion of the elongated slot is parallel to the central axis of the lift arm; and
a pin configured to move within the elongated slot wherein the pin is driven by a drive system.
2. The window regulator mechanism according to claim 1  wherein the drive system comprises gear mechanism.
3. The window regulator mechanism according to claim 2  wherein the gear mechanism is rack and pinion.
4. The window regulator mechanism according to claim 1  further comprising a rack wherein the pin is positioned on the rack.
5. The window regulator mechanism according to claim 1  wherein the window regulator mechanism is cross arm type.
6. The window regulator mechanism according to claim 1  wherein the window regulator mechanism is single arm type.
7. A window regulator mechanism for moving a windowpane  the window regulator mechanism comprising:
a rack comprising an elongated slot having an angular deviation; and
a lift arm operably coupled to the rack; wherein the lift arm comprises a pin configured to move within the elongated slot and wherein a substantial portion of the elongated slot is parallel to the central axis of the lift arm.
8. The window regulator mechanism according to claim 7  wherein the rack is driven by a drive system.
9. The window regulator mechanism according to claim 7  wherein the pin is operably coupled to the elongated slot such that motion in the rack is transformed into motion of the lift arm.
10. The window regulator mechanism according to claim 7  wherein the drive system comprises gear mechanism and the gear mechanism is rack and pinion.