The present disclosure relates to the field of means and methods of error-proofing implemented in an automotive manufacturing plant. Particularly, the present disclosure relates to prevention of error due to non-engagement of locating pins with a component held in a fixture of a horizontal grinding machine.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Machining operations require precise positioning of a partially finished component on a fixture to ensure that the desired dimensional tolerances are achieved. Without precise positioning of the component, the surface of the component is likely to be under- or over- machined, or the component may move during machining, thereby leading to rejection of the component.
Locating pins, buttons, pads are locators that are used for location of the component relative to a plane surface of the station of a machining device. These locators are manufactured separately from the fixture or the jig. Locating pins are cylindrical components that are used as side stops or for locating inside holes formed in the component. Locating pins are located inside holes provided in the component by press fitting. Locating pins are either fixed to the surface of the fixture/pallet or are displaceable by means of a mechanism, in and out of the surface of the fixture/pallet.
Typically, an operator manually loads the component on a station such as a fixture. The operator manually inserts the locating pins in the component to align the component on the fixture. After the locating pins are inserted and the clamps of the fixture clamp the component in position, the operator pushes the "pallet ready" pushbutton on a PLC input panel, which commands the PLC to start the further cycle and machining starts on the component.

If the operator mistakenly forgets to insert the locating pins in the component, the reference points get shifted, which results into rejection of the component.
It is evident, therefore, that there is no means known for confirmation of insertion of the locating pins except for physically checking the insertion of the locating pins, since the locating pins are hidden from the sight underneath the component.
Therefore, a means, to prevent commencement of the machining operation by the machining tool until the component to be machined is operatively precisely clamped on the machining station, is desired.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a means for prevention of error due to non-engagement of locating pins with a component to be machined.
Yet another object of the present disclosure is to provide a means for prevention of error due to non-engagement of locating pins with a component to be machined, which is fool-proof.
Still another object of the present disclosure is to provide a means for prevention of error due to non-engagement of locating pins with a component to be machined, which is independent of human error and does not require human intervention.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

The present disclosure envisages a machining device for performing a machining operation by a machining tool on a component. The component is clamped on a machining station of the device. The machining device comprises means to prevent commencement of the machining operation by the machining tool until the component to be machined is operatively precisely clamped on the machining station.
In a preferred embodiment, the means comprises a plurality of locating pins, a locating pin actuator and a sensor. The locating pins are configured to be displaced to an engaging state out of a surface of the machining station and be engaged with corresponding holes provided in the component for precise placement of the component on the machining station. The locating pin actuator is configured to be actuated for displacing the locating pins in the engaging state. The control unit of the machining device is configured to control commencement of machining operation by the machining device. The sensor is communicatively coupled to the control unit. The sensor is positioned to detect the locating pin actuator in a position corresponding to the engaging state of the locating pins and generate a signal corresponding to detection of the locating pin actuator. The control unit of the machining device is configured to prevent machining operation of the machining device if the control unit does not receive the signal from the sensor.
In an embodiment, the locating pin actuator is provided with an appendage attached thereto. The appendage is configured to be displaced along with the locating pin actuator and be sensed by the sensor.
The sensor is a contact-type sensor or a non-contact-type sensor. In an embodiment, the sensor is a proximity sensor.
In an embodiment, the sensor is mounted on a sensor stand.
In an embodiment, the locating pin actuator is angularly displaceable.
In an embodiment, the machining station is a fixture

BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
A machining device of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 shows a front view of a fixture for holding a component for milling operation fitted on the machining device according to an embodiment of the present disclosure;
Figure 2 illustrates a close-up view of the error prevention means of the machining device of Figure 1;
Figure 3 shows an isometric view of the fixture of Figure 1;
Figure 4 illustrates a top view of the fixture showing locating pins in an engaged state; and
Figure 5 illustrates a top view of the fixture showing locating pins in a disengaged state.
LIST OF REFERENCE NUMERALS
100 station / fixture
10 fixture body
12 pallet
14 clamp
16 clamp screw
18 guiding member
20 locating pin
22 locating pin actuator
30 sensor

32 appendage
34 sensor stand
200 component
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as 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 and methods, 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.
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", "including" and "having" are open ended transitional phrases and therefore specify the presence of stated features, steps, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, steps, elements, components, and/or groups thereof.
When an element is referred to as being "mounted on", "engaged to", "connected to" or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element.

Terms such as "inner", "outer", "beneath", "below", "lower", "above", "upper" and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
A component to be machined on a machining device such as a horizontal milling centre (HMC) (not shown in Figure) is held in place on a station which can be a fixture. The component is brought over the fixture by hooking the component onto a hanger. The fixture has guiding members for guiding the placement of a component to be held therein at an approximately accurate position. The fixture is provided with displaceable locating pins that probe out of a pallet of the fixture when a locating pin actuator is actuated manually to that effect by an operator. The component is provided with holes that are positioned to press-fittingly receive the locating pins.
After placing the component on the pallet, if the operator fails to actuate the locating pin actuator to bring the locating pins in an engaged state from their disengaged state, the movement of the component is not properly constrained against the force of the grinding machine and nearby vibration. Therefore, there is a need of a means for prevention of error due to non-engagement of locating pins with a component to be machined, which is fool-proof, which is independent of human error and which does not require human intervention.
The present disclosure envisages a machining device for performing a machining operation by a machining tool on a component, as illustrated through Figures 1-5. The component 200 is clamped on a machining station of the device. The machining device comprises means to prevent commencement of the machining operation by the machining tool (hereinafter referred to as 'error prevention means' for the sake of brevity) until the component to be machined is operatively precisely clamped on the machining station. In an embodiment, the machining device is a horizontal grinding machine.
The means comprises locating pins 20, a locating pin actuator 22 and a sensor 30. The locating pins 20 are configured to be displaced to an engaging state out of a

surface of the machining station and be engaged with corresponding holes provided in the component for precise placement of the component 200 on the machining station. The locating pin actuator 22 is configured to be actuated for displacing the locating pins 20 in the engaging state. The control unit of the machining device is configured to control commencement of machining operation by the machining device. The sensor 30 is communicatively coupled to the control unit. The sensor 30 is positioned to detect the locating pin actuator 22 in a position corresponding to the engaging state of the locating pins 20 and generate a signal corresponding to detection of the locating pin actuator 22. The control unit of the machining device is configured to prevent machining operation of the machining device if the control unit does not receive the signal from the sensor 30.
In an embodiment, the locating pin actuator 22 is provided with an appendage 32 attached thereto. The appendage 32 is configured to be displaced along with the locating pin actuator 22 and be sensed by the sensor 30 in a position corresponding to the engaging state of the locating pins 20.
In an embodiment, the machining station is a fixture 100 for clamping the component 200 for machining operation. The fixture 100 has a pallet 12 for receiving the component 200 and clamps 14 for clamping the component 200 placed on the pallet 12. The clamps 14 have screws 16 for tightening the clamps 14 against the component 200.
In an embodiment, the locating pin actuator 22 is angularly displaceable. The locating pin actuator 22 is a handle 22 which turns a shaft (not shown in figures), and the shaft is coupled to the locating pins 20 which are raised out of the operative surface of the pallet 12 of the fixture 100. When the component 200 to be machined is placed on the pallet 12 and is clamped in position by tightening the screws 16 of the clamps 14, the handle 22 is turned to raise the locating pins 20 in an engaging state and press-fit the locating pins 20 into corresponding holes provided in the surface of the component 200 that is rested on the operative surface of the pallet 12. Along with the handle 22, the appendage 32 also turns

and comes in a position in which the appendage 32 is sensed by the sensor 30. The sensor 30 generates a signal that is communicated to the control unit of the horizontal milling centre. When the operator pushes a switch for initiating the machining operation of the horizontal milling centre, since the control unit has received the sensed signal from the sensor 30, the control unit allows the machining operation on the component 200.
Thus, by prevention of initiation of machining operation in the absence of precise positioning of the component 200, the error prevention means of the present disclosure prevents damage to the component 200 and resultant component rejection. Moreover, being automated and directly integrated with the control system of the milling machine, the error prevention means is fool-proof and does not require any human intervention.
In an embodiment, the sensor 30 is mounted on a sensor stand 34.
In an embodiment, the sensor 30 is a contact-type sensor. In another embodiment, the sensor is a non-contact-type sensor. In an embodiment, the sensor is a proximity sensor. The proximity sensor can be selected from the group consisting of an inductive proximity sensor, a capacitive proximity sensor, an ultrasonic proximity sensor, an optical proximity sensor, a Hall Effect proximity sensor, and an infrared proximity sensor.
Preferably, the control unit is a programmable control unit. The control unit is configured to cooperate with a repository of instructions. The control unit is configured to generate processing commands. The control unit can be implemented as one or more microprocessors, microcomputers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular

embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a machining device having means for prevention of error, wherein said means for prevention of error:
• is fool-proof; and
• is independent of human error and does not require human intervention.
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.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
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 of 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.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

WE CLAIM

1.A machining device for performing a machining operation by a machining tool on a component (200), said component (200) clamped on a machining station (100) of the device, said device comprising means to prevent commencement of the machining operation by the machining tool until the component (200) to be machined is operatively precisely clamped on the machining station (100).
2. The machining device as claimed in claim 1, wherein said means comprises:

• a plurality of locating pins (20) configured to be displaced to an engaging state out of a surface of the machining station (100) and be engaged with corresponding holes provided in said component (200) for precise placement of said component (200) on said machining station (100);
• a locating pin actuator (22) configured to be actuated for displacing said locating pins (20) in said engaging state;
• a control unit configured to control commencement of machining operation by said machining device;
• a sensor (30) communicatively coupled to said control unit, said sensor (30) positioned to detect the locating pin actuator (22) in a position corresponding to the engaging state of the locating pins (20) and generate a signal corresponding to detection of said locating pin actuator (22);
wherein the control unit of said machining device is configured to prevent machining operation of the machining device if the control unit does not receive said signal from said sensor (30).
3. The machining device means as claimed in claim 2, wherein said locating pin
actuator (22) is provided with an appendage (32) attached thereto, said

appendage (32) configured to displace along with the locating pin actuator (22) and be sensed by said sensor (30).
4. The machining device as claimed in claim 2, wherein said sensor (30) is a contact-type sensor.
5. The machining device as claimed in claim 2, wherein said sensor (30) is a non-contact-type sensor.
6. The machining device as claimed in claim 5, wherein said sensor (30) is a proximity sensor.
7. The machining device as claimed in claim 2, wherein said sensor (30) is mounted on a sensor stand (34).
8. The machining device as claimed in claim 2, wherein said locating pin actuator (22) is angularly displaceable.
9. The machining device as claimed in claim 1, wherein machining station (100) is a fixture.