Description:FORM 2
THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See Section 10, Rule 13]

A ROTARY CAM ASSEMBLY FOR A MACHINE PRESS

BY
MAHINDRA & MAHINDRA LIMITED, A COMPANY REGISTERED UNDER THE INDIAN COMPANIES ACT, 1913, HAVING ADDRESS AT MAHINDRA RESEARCH VALLEY (MRV), MAHINDRA WORLD CITY, PLOT NO.41/1, ANJUR P.O., CHENGALPATTU, KANCHIPURAM DISTRICT, TAMILNADU – 603004, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A ROTARY CAM ASSEMBLY FOR A MACHINE PRESS
FIELD OF THE INVENTION
The present disclosure relates to a rotary cam assembly for a machine press.

BACKGROUND OF THE INVENTION
For manufacturing of certain vehicle parts, a machine press is used. The machine press consists of a plurality of dies. The vehicle parts are formed after a sheet metal passes through all the dies of the machine press. For manufacturing of a fender of the vehicle, the sheet metal passes through four dies. The fender of the vehicle has a complex structure and has a negative feature. The negative feature is a portion of the fender which is not perpendicular to the machine press direction. The negative feature of the fender is formed in the fourth die of the machine press.
Conventionally, for the formation of the negative feature, a double acting drop cam is used. The double acting drop cam is a type of cam which uses a combination of vertical, horizontal, and angular movements for the formation of a component in the machine press. The double acting drop cam has a complicated assembly with a plurality of moving parts. The double acting drop cam used for manufacturing the negative feature of the fender has a driver, a slider, and a drop cam. The driver is a part of the upper die and it moves in the vertical direction. The slider is a part of the lower die and it moves in the horizontal direction. The drop cam is a part of the lower die and it moves in the angular direction. The double acting drop cam forms the negative feature by the combined motion of all three parts of the double acting drop cam. The double acting drop cam requires a lot of space. Due to its complex design, the fenders formed by the double acting drop cam also have quality issues like, poor finish of the surface.
Therefore, there is a need for a compact way of manufacturing the vehicle component in the machine press, that is not complex and provides high quality parts without issues.

SUMMARY OF THE INVENTION
In one embodiment of the present disclosure, a rotary cam assembly for a machine press is provided. The rotary cam assembly includes a cam slider fixedly coupled to a ram of the machine press. The cam slider is movable along both vertical direction and horizontal direction between a top dead center (TDC) and a bottom dead center (BDC). The cam slider has an insert attached thereon and a retraction spring operatively coupled along the horizontal direction. The rotary cam assembly also includes a rotary cam unit fixedly coupled to a holder of the machine press. The rotary cam unit has a cam casing. The rotary cam unit also has a rotor rotatably disposed in the cam casing. The rotor rotates about an axis perpendicular to the vertical direction and the horizontal direction of the cam slider movement. The rotor has a wear plate on which the cam slider slides in an oblique direction at a particular cam angle, thereby, causing the rotor to rotate. The rotor receives the cam slider and the insert therein at the BDC to form a negative feature on a sheet metal disposed between the insert and the rotor. The rotary cam unit further includes an actuator having a plunger. The actuator is operatively coupled to the rotor. The rotary cam unit also includes a sensor communicably coupled to the rotor, the actuator, and a controller of the machine press. The sensor detects the position of the rotor when cam slider starts sliding on the wear plate of the rotor and the rotor starts rotating. The controller is configured to actuate the actuator to rotate the rotor and to move the ram of the machine press down along the vertical direction simultaneously, thereby, allowing the cam slider to reach the BDC based on the position of the rotor. Further, the controller is configured to actuate the actuator to rotate back the rotor once the ram of the machine press starts moving vertically upwards. The retraction spring pushes the cam slider in horizontal direction at original position when the cam slider loses the contact with the wear plate of the rotor. The controller is also configured to send a signal to the machine press for removal of the formed sheet metal from the rotary cam assembly.
According to the present invention, the actuator of the rotary cam unit and the cam casing of the rotary cam unit are mounted on a cam mounting base which is fixedly coupled to the holder.
According to the present invention, the actuator is a pneumatic actuator.
According to the present invention, the rotary unit has a rotor stopper mounted on the cam casing to stop the rotation of the rotor and a pair of guiding plates to guide the rotor.
According to the present invention, the sensor is a proximity sensor.
According to the present invention, the cam slider has a pair of slider guide wear plates to guide the cam slider in an upper die of the machine press.
According to the present invention, the retraction spring is a gas spring.
According to the present invention, the wear plate of the rotor has a sensor attachment disposed thereon.

BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 illustrates an exploded view of a rotary cam assembly, according to the present disclosure;
FIG. 2 illustrates a perspective view of a slider of the rotary cam assembly, according to the present disclosure;
FIG. 3 illustrates a perspective view of a rotary cam unit, according to the present disclosure;
FIG. 4 illustrates a perspective view of the slider and the rotary cam unit at a top dead centre (TDC), according to the present disclosure;
FIG. 5 illustrates a perspective view of the slider and the rotary cam unit at a bottom dead centre (BDC), according to the present disclosure;
FIG. 6 illustrates a perspective view of a sheet metal being formed in the rotary cam assembly, according to the present disclosure;
FIG. 7 illustrates a perspective view of a fender of a vehicle, according to the present disclosure; and
FIG. 8 illustrates a flow chart of various steps for manufacturing the fender using the rotary cam assembly, according to the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawings.
Embodiments are provided to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth relating to specific components to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
References in the present disclosure to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in an embodiment” or “in an implementation” in various places in the specification are not necessarily all referring to the same embodiment or implementation.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises,” “comprising,” “consists,” “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated elements, modules, units and/or components, but do not forbid the presence or addition of one or more other elements, components, and/or groups thereof.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
FIG. 1 illustrates an exploded view of a rotary cam assembly (100) for a machine press (not shown). The rotary cam assembly (100) consists of a cam slider (102), and a rotary cam unit (104). The cam slider (102) is fixedly coupled to a ram (not shown) of the machine press. The cam slider (102) has an insert (106) attached thereon. In the illustrated embodiment of the present disclosure, the insert (106) has a square shape. It should be noted that the insert (106) may have any other shape as per application requirement without limiting the scope of the present disclosure. Further, a retraction spring (108) is operatively coupled to the cam slider (102). In the illustrated embodiment of the present disclosure, the retraction spring (108) is a gas spring. It should be noted that the retraction spring (108) may have any other type without limiting the scope of the present disclosure. Further, the cam slider (102) also has a pair of slider guide wear plates (110) and a safety guide plate (112) attached thereon. The slider guide wear plates (110) guide the cam slider (102) in an upper die (not shown) of the machine press. The safety guide plate (112) ensures the cam slider (102) is safely held on the ram of the machine press.
As illustrated in FIG. 2, the cam slider (102) is movable along both a vertical direction and a horizontal direction. The cam slider (102) moves between a top dead center (TDC) and a bottom dead center (BDC) of the ram. The retraction spring (108) is operatively coupled to the cam slider (102) along the horizontal direction.
Referring to FIG. 1, the rotary cam unit (104) is fixedly coupled to a holder (114) of the machine press. The rotary cam unit (104) has a cam casing (116), a rotor (118), an actuator (120), a sensor (122), and a controller (not shown). The rotor (118) is rotatably disposed in the cam casing (116). The cam casing (116) performs the function of guiding and housing the rotor (118). Further, the cam casing (116) has a rotor stopper (124) and a pair of guiding plates (126). The pair of guiding plates (126) guide the rotor (118) in the cam casing (116) and also lock side motion of the rotor (118). The rotor stopper (124) ensures the rotor (118) is stopped positively. A wear plate (128) is fixedly attached on the rotor (118). The wear plate (128) provides a sliding surface to the cam slider (102) and guides the cam slider (102) when cam slider (102) slides on the wear plate (128).
The actuator (120) is a pneumatic actuator. Further, the actuator (120) is a double acting pneumatic actuator. The actuator (120) is operated by compressed air of the machine press. The actuator (120) and the cam casing (116) are mounted on a cam mounting base (130). The cam mounting base (130) is fixedly coupled to the holder (114) of the machine press. The actuator (120) is operatively coupled to the rotor (118). Further, the actuator (120) includes a plunger (132). The plunger (132) of the actuator (120) is connected to a rotor attachment (134). In the illustrated embodiment of the present disclosure, the rotor attachment (134) is a universal joint. It should be noted that the rotor attachment (134) may have any other type without limiting the scope of the present disclosure.
In the illustrated embodiment of the present disclosure, the sensor (122) is a proximity sensor. It should be noted that the sensor (122) may have any other type without limiting the scope of the present disclosure. The sensor (122) is communicably coupled to the rotor (118), the actuator (120), and the controller of the machine press. Further, a sensor attachment (136) is disposed on the wear plate (128) of the rotor (118). The sensor attachment (136) helps sense BDC condition of the rotor (118).
In the illustrated embodiment of the present disclosure, the controller is configured to send a first signal to actuate the actuator (120) for rotation of the rotor (118) and to move the ram of the machine press down along the vertical direction simultaneously, thereby, allowing the cam slider (102) to reach the BDC. Further, the controller is configured to actuate the actuator (120) to rotate back the rotor (118) once the ram of the machine press starts moving vertically upwards. The controller actuates the actuator (120) once the ram starts moving vertically upwards. The controller is also configured to send a signal to the machine press for removal of the formed sheet metal (137) from the rotary cam assembly (100).
As illustrated in FIG. 3, the rotor (118) rotates about an axis perpendicular to the vertical direction and the horizontal direction of the cam slider (102) movement.
FIG. 4 illustrates the rotary cam assembly (100) when the ram is at the TDC. At TDC, a sheet metal (137) is disposed into the rotary cam assembly (100) between the insert (106) and rotor (118). After the sheet metal (137) is disposed in the rotary cam assembly (100) the ram moves in the vertically downward direction. The cam slider (102) moves along with the ram. The cam slider (102) is guided along the guide wear plates (110). When the cam slider (102) contacts the wear plate (128) of the rotor (118), the cam slider (102) starts sliding in an oblique direction, at a particular cam angle, on the wear plate (128) of the rotor (118), thereby, causing the rotor (118) to rotate. The sensor (122) detects the position of the rotor (118) when cam slider (102) starts sliding on the wear plate (128) of the rotor (118) and the rotor (118) starts rotating. The controller sends the first signal to actuate the actuator (120) to rotate the rotor (118) and simultaneously move the ram down along the vertical direction when the cam slider (102) slides on the wear plate (128) of the rotor (118). The rotor attachment (134) converts the axial motion of the plunger (132) of the actuator (120) into rotary motion of the rotor (118). The sliding of the cam slider (102) along the wear plate (128) and the action of the actuator (120) combined, rotate the rotor (118).
As illustrated in FIG. 5, the rotor (118) receives the cam slider (102) and the insert (106) therein at the BDC to form a negative feature (138) on the sheet metal (137) disposed between the insert (106) and the rotor (118). The negative feature (138) is a portion of a fender (140) which is not perpendicular to the machine press direction. The negative feature (138) is formed on the sheet metal (137) by the combined motion of the rotor (118) and the insert (106), when the rotor (118) is stopped by the rotor stopper (124).
As illustrated in FIG. 6, the negative feature (138) is formed on the sheet metal (137). After the negative feature (138) is formed, the ram starts moving in a vertically upward direction. The retraction spring (108) pushes the cam slider (102) in horizontal direction at original position when the cam slider (102) loses the contact with the wear plate (128) of the rotor (118). The controller then sends the signal for removal of the sheet metal (137) from the rotary cam assembly (100).
FIG. 7 illustrates the fender (140) manufactured from the sheet metal (137) with the negative feature (138).
FIG. 8 illustrates a flow chart (800) of various steps for manufacturing the fender using the rotary cam assembly. At step 802, the process starts. At step 804, the ram moves vertically downwards after the sheet metal is disposed between the insert and rotor in the rotary cam assembly at TDC. At step 806, the cam slider then slides along the wear plate of the rotor in an oblique direction, at a particular cam angle, causing the rotor to rotate. At step 808, the sensor senses the position of the rotor. At step 810, the controller actuates the actuator to rotate the rotor. At step 812, the controller simultaneously lowers the cam slider along the vertical direction to reach at BDC, to form the negative feature. At step 814, the ram moves vertically downwards till the rotor is stopped by the rotor stopper. At step 816, the ram then moves vertically upwards. At step 818, the controller actuates the actuator to rotate back the rotor. At step 820, the retraction spring pushes the cam slider in a horizontal direction when the ram moves vertically upwards. At step 822, the controller sends a signal to the machine press to remove the formed sheet metal from the rotary cam assembly. At step 824, the process ends.
The present invention provides a compact alternative to the double acting drop cam for the formation of a fender in the machine press.
The present invention also eliminates the need for a fourth die for formation of the negative feature of the fender. The fender is manufactured by passing through three dies in the machine press.
The elimination of the fourth die reduces the machine time of the component to be formed and eliminates the cost of manufacturing of the fourth die.
The present invention provides a better quality of the vehicle part formed.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
Any discussion of devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
, Claims:
1. A rotary cam assembly (100) for a machine press, the rotary cam assembly (100) comprising:
a cam slider (102) fixedly coupled to a ram of the machine press, the cam slider (102) is movable along both vertical direction and horizontal direction between a top dead center (TDC) and a bottom dead center (BDC), the cam slider (102) has an insert (106) attached thereon and a retraction spring (108) operatively coupled along the horizontal direction; and
a rotary cam unit (104) fixedly coupled to a holder (114) of the machine press, the rotary cam unit (104) having:
a cam casing (116);
a rotor (118) rotatably disposed in the cam casing (116) and rotating about an axis perpendicular to the vertical direction and the horizontal direction of the cam slider (102) movement, the rotor (118) has a wear plate (128) on which the cam slider (102) slides in an oblique direction at a particular cam angle, thereby, causing the rotor (118) to rotate, the rotor (118) receives the cam slider (102) and the insert (106) therein at the BDC to form a negative feature (138) on a sheet metal (137) disposed between the insert (106) and the rotor (118);
an actuator (120) having a plunger (132), the actuator (120) operatively coupled to the rotor (118);
a sensor (122) communicably coupled to the rotor (118), the actuator (120), and a controller, the sensor (122) is configured to detect the position of the rotor (118) when cam slider (102) starts sliding on the wear plate (128) of the rotor (118) and the rotor (118) starts rotating; and
the controller is configured to:
actuate the actuator (120) to rotate the rotor (118) and to move the ram of the machine press down along the vertical direction simultaneously, thereby, allowing the cam slider (102) to reach at the BDC based on the position of the rotor (118);
actuate the actuator (120) to rotate back the rotor (118) once the ram of the machine press starts moving vertically upwards, the retraction spring (108) pushes the cam slider (102) in horizontal direction at original position when the cam slider (102) loses the contact with the wear plate (128) of the rotor (118); and
send a signal to the machine press for removal of the formed sheet metal (137) from the rotary cam assembly (100).
2. The rotary cam assembly (100) as claimed in claim 1, wherein the actuator (120) of the rotary cam unit (104) and the cam casing (116) of the rotary cam unit (104) are mounted on a cam mounting base (130) which is fixedly coupled to the holder (114).
3. The rotary cam assembly (100) as claimed in claim 1 or claim 2, wherein the actuator (120) is a pneumatic actuator.
4. The rotary cam assembly (100) as claimed in any one of claims 1 to 3, wherein the rotary cam unit (104) has a rotor stopper (124) mounted on the cam casing (116) to stop the rotation of the rotor (118) and a pair of guiding plates (126) to guide the rotor (118).
5. The rotary cam assembly (100) as claimed in claim 1, wherein the sensor (122) is a proximity sensor.
6. The rotary cam assembly (100) as claimed in claim 1, wherein the cam slider (102) has a pair of slider guide wear plates (110) to guide the cam slider (102) in an upper die of the machine press.
7. The rotary cam assembly (100) as claimed in claim 1, wherein the retraction spring (108) is a gas spring.
8. The rotary cam assembly (100) as claimed in claim 1, wherein the wear plate (128) of the rotor (118) has a sensor attachment (136) disposed thereon.