DESC:FIELD OF INVENTION

[001] The present invention relates to sanding of ring gears. In particular, the present invention relates to a single touch ring gear sanding machine. More particularly, the present invention relates to a special purpose machine which is used for single-touch sequential sanding of multiple ring gears.

BACKGROUND OF THE INVENTION

[002] Ring gears are used in many types of gearing arrangements in mechanical engineering, e.g. flywheel ring gears and combining case in tractors and in starter motors. Normally, the non-engaging surfaces of the ring gears are painted to protect it from corrosion in contaminated environment.

[003] The applicant is one of the leading manufacturers of tractors and agricultural and farm equipment and such ring gears form one of the important components of their product line. A recent product launched in the market was reported having paint peel-off defects in many ring gears used therein. This resulted in bare surfaces and the corrosion thereof was observed, which is unacceptable from the customer goodwill in the market and from the utility point of view thereof.

[004] The cause and effect analysis pointed to two main probable reasons for this defect, the first reason could be the material having high roughness average (Ra) value used for making these ring gears and the second reason could be non-uniform load application during the sanding operation of these ring gears. Both these could have led to these ring gears failure in paint adhesion tests.

[005] Ring gear painting operation basically involves making or obtaining unpainted ring gears, then sanding their non-engaging outer periphery manually and finally painting the surface thereafter. Since the existing process of ring gear painting is a completely manual process, there is little control over the uniformity of sanding operation on these ring gear surfaces.
PRIOR ART

[006] At present, two-axis sanding and polishing machine like HBS 1600 is available for sanding various components. Similarly, multi-axis sanding machines are also available, which include an automatic compact robotic sanding system, however it is quite complex due to multiple axis thereof, which are actually not required and not useful for simple single surface sanding applications like in ring gears.

[007] US2735242 discloses a multiple sanding device having at least two operating parts permanently secured thereto, which may be interchangeably connected automatically with a single driving force by mere tilting of the housing of one to another operating position by using a hand operated coupling lever.

DISADVANTAGES WITH THE PRIOR ART

[008] The ring gear painting application requires painting only on the outer circumference thereof and there is little check over the load applied during sanding of ring gears. So, ensuring a uniform sanding on the surfaces of the ring gears subsequently to be painted, is quite a difficult task. Moreover, the productivity of the available sanding machines is very low and thus cost per job is substantially higher. Further, no digitized sanding machines with applied load indication are presently available in the market.

[009] Therefore, there is an existing need for developing a low-cost ring gear sanding machine, which is simple and easy to manufacture and maintain, and which can facilitate a uniform load application during sanding of ring gears.

[010] This ring gear sanding machine should also satisfy the high-productivity demanded in today’s competitive market, in order to obtain a uniformly sanded ring gear. This would improve the quality of subsequent painting operation thereon and completely eliminate the paint peel-off defect, often observed in such ring gears.

DESCRIPTION OF THE PRESENT INVENTION

[011] The applicant’s chassis painting application also uses 7-axis robots with rotary movement for chassis painting applications costing about 2 crores in one of their farm-equipment manufacturing facilities, which actually became the starting point for development of a simple, low-cost, 2-axis ring gear sending machine with a linear movement along with the rotation of the ring gears to be sanded.

[012] Accordingly, a fixture specially configured with guide rods for placing ring gears in linear position is made. It comprises a load cell installed with a sanding machine to check the load applied on ring gears to be sanded and displaying this load on the control unit thereof. It further includes a clamping cylinder, preferably with a 25 mm stroke, for adjusting the sanding process during oscillations. A gear box unit is used to rotate the ring gears at a low-speed of about 17 rpm. An electronic timer is also incorporated in the control circuit logic to adjust the cycle time in the control unit.

[013] Accordingly, sanding of about 14 ring gears can be done in one cycle. The main components of this ring gear sanding machine are:

• Fixture 90 for holding a plurality of ring gears 80 to be sanded.

• First pneumatic cylinder 30 for vertical movement of sanding unit 10, preferably having 600 mm stroke.

• Second pneumatic cylinder 40 for clamping the sanding unit 10 to ring gears, preferably having 25 mm stroke.

• Sanding unit 10, preferably a 5” unit rotating at 2000 rpm.

• Load cell 20 (capacity 0-10 kg) with a digital display controller.

• Control unit ECU incorporating an electronic timer ET, preferably a star-delta timer provided in its control circuit logic to adjust the cycle time.

• Low-speed gear box 50 driven by an electric motor 60, preferably a 3-phase induction motor to rotate the plurality of ring gears 80 loaded on fixture 90, preferably at about 17 rpm.

• Control panel CP for operating the sanding machine.

[014] The characteristic features of this new sanding machine are as given below:

- Robust and unique configuration having a fixture loaded with ring gears rotating at low speed for sanding by linearly moving sanding unit.

- Pneumatic and electronic circuit.

- Integrated load cell to display the load applied by the sanding unit during sanding operation therewith.

- Higher productivity.

- Uniform sanding operation, thereby eliminating paint peel-off defect.

- Improves the ring gear quality.

- Eliminates non-value adding activities of operator, thus improves operator’s efficiency.

- Offers substantial cost-saving of input materials, e.g. sand paper.

OBJECTS OF THE INVENTION

[015] Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

[016] An object of the present invention is to provide a robust, low-cost, high-productivity sanding machine.

[017] Another object of the present invention is to provide a sanding machine with linear movement.

[018] Still another object of the present invention is to provide an improved sanding machine to eliminate paint peel-off defect after painting of sanded ring gears.

[019] Yet another object of the present invention is to provide an improved single-touch sanding machine which displays sanding load applied on ring gears during sanding thereof.

[020] A further object of the present invention is to provide an improved single-touch sanding machine which improves the productivity of ring gear sanding process.

[021] A still further object of the present invention is to provide an improved single-touch sanding machine which improves the operator’s efficiency during ring gear sanding process.

[022] These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

[023] In accordance with an embodiment of the present invention, there is provided an electronically-controlled, single-touch, multiple ring-gear sanding machine comprising:

• a sanding unit;

• a load cell integrated with the sanding unit;

• a first cylinder to operate the sanding unit;

• a second cylinder to operate the first cylinder;

• a gear box to operate the second cylinder;

• an electric motor for operating the gear box;

• a rotatable fixture for stacked mounting of a plurality of ring gears to be sanded before painting thereof;

• a table for mounting the first and second cylinders, the gear-box connected to the electric motor and the rotatable fixture; and

• an operator’s box provided beside the table for accommodating a control panel of the single touch ring gear sanding machine;

wherein the sanding unit comprises an electronic control unit (ECU) having an electronic timer (ET) for adjusting cycle time thereof, depending on number of ring gears to be sanded per cycle, the electronic control unit (ECU) and the load-cell display fitted on the operator’s box.

[024] Typically, the sanding unit is a linearly moving sanding unit comprising a sanding tool rotating at a speed varied from 1500 rpm to 2000 rpm.

[025] Typically, the load cell is integrated with the sanding tool to continuously measure the load applied on the ring gears during sanding thereof and to display on the electronic control unit (ECU) fitted on the operator’s box, and the load cell comprises digital display controller with load measuring capacity in the range of 0-10 kg.

[026] Typically, the first cylinder is configured for vertical to-and-fro movement of the sanding unit depending on the number of ring gears loaded on the rotatable fixture to be sanded per cycle.

[027] Typically, the first cylinder is a pneumatic cylinder having a 300-1400 mm stroke.

[028] Typically, the second cylinder is configured for clamping the sanding unit to the ring gears loaded on the rotatable fixture; and the second cylinder is a pneumatic cylinder having a 15-35 mm stroke.

[029] Typically, the gear-box is a low-speed gear-box to rotate the plurality of ring gears, the gear box rotating at a speed varied from 15 rpm to 20 rpm.

[030] Typically, the electric motor is a 3-phase induction motor.

[031] Typically, the sanding unit is vertically moved multiple times to obtain the targeted surface roughness (Ra) for subsequent painting operation on the ring gear.

[032] In accordance with another embodiment of the present invention, there is provided an electronically-controlled, single-touch, multiple ring-gear sanding machine comprising:

• a linearly moving sanding unit comprising a sanding tool rotating at a speed varied from 15 rpm to 20 rpm;

• a load cell integrated with the sanding unit to continuously measure load applied on the ring gears and display on a digital display controller; the load cell has a load capacity in a range of 0-20 kg;

• a first cylinder configured as a pneumatic cylinder for vertical to-and-fro movement of the sanding unit, the pneumatic cylinder having about 500-800 mm stroke based on the number of ring gears to be sanded per cycle;

• a second cylinder to operate the first cylinder configured for clamping the sanding unit to the ring gears, and having a 15-35 mm stroke;

• a low-speed gear-box to rotate the plurality of ring gears as well as to operate the second cylinder, the gear box rotating at about 15-20 rpm;

• a motor for operating the gear box;

• a rotatable fixture for stacked mounting of the ring gears to be sanded before painting thereof;

• a table for mounting the first and second pneumatic cylinders, the gear-box connected to the motor and the rotatable fixture; and

• an operator’s box provided beside the table for accommodating a control panel of the single touch ring gear sanding machine;

wherein the sanding unit comprises an electronic control unit (ECU) having an electronic timer (ET) for adjusting the cycle time thereof, depending on the number of ring gears to be sanded per cycle, the electronic control unit (ECU) and the load-cell display fitted on the operator’s box; and wherein the sanding unit is vertically moved to-and-fro multiple times depending on targeted surface roughness (Ra) for subsequent painting operation on the ring gears.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[033] The present invention will be briefly described with reference to the accompanying drawings, which include:

[034] Figure 1 shows a linearly moving sanding machine configured in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[035] In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

[036] Figure 1 shows a linearly moving sanding machine configured in accordance with the present invention. It comprises a sanding unit 10 equipped with a load cell 20 and operated by means of a first pneumatic cylinder 30, which in turn is moved by a second pneumatic cylinder 40 operated by a gear box 50 run by a 3-phase induction motor 60. The cylinders 30, 40, gear box 50 and motor 60 are mounted on a table 70. A plurality of ring gears 80 to be sanded are mounted stacked on a rotatable fixture 90 also mounted on table 70. An operator’s box 100 is also provided beside the table 70 accommodating the sanding machine. The sanding unit is vertically moved to-and-fro (in direction V) by means of the first pneumatic cylinder 30 which in turn is connected to the second pneumatic cylinder 40 linearly (in direction L) operated the gear box 50. Thus, the ring gears 80 loaded on rotatable fixture 90 are vertically moved (in direction R) multiple times, e.g. three times, depending on the targeted surface roughness (Ra) on these ring gears 80 for subsequent painting operation to be done externally thereon after sending operation.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

[037] The low-cost, high-productivity single-touch sanding machine configured in accordance with the present invention has the following advantages:

- Robust and unique configuration.
- Linear movement of ring gears.
- Pneumatic and electronic circuit.
- Integrated load cell to display the applied load.
- Higher productivity.
- Uniform sanding operation.
- Improved the ring gear quality.
- Operator’s non-value adding activities eliminated to improve his efficiency.
- Substantial cost-saving by using less sand papers.

[038] It is to be understood that the present invention is not limited in its application to the details of the construction and to the arrangements of the components as mentioned in the above description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the terminologies used herein are for the purpose of description and should not be regarded as limiting.

[039] The foregoing description of the specific embodiments will 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. 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 distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

[040] The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

[041] Therefore, while the embodiments herein have been described in terms of preferred embodiments, the skilled person will recognize that the embodiments herein can be practiced with modification within the spirit and scope of embodiments described herein.

[042] The skilled person can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

[043] The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

[044] Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

[045] The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. ,CLAIMS:We claim:

1. An electronically-controlled, single-touch multiple ring-gear sanding machine comprising:

• a sanding unit (10);

• a load cell (20) integrated with said sanding unit (10);

• a first cylinder (30) to operate said sanding unit (10);

• a second cylinder (40) to operate said first cylinder (30);

• a gear box (50) to operate said second cylinder (40);

• an electric motor (60) for operating said gear box (50);

• a rotatable fixture (90) for stacked mounting of a plurality of ring gears (80) to be sanded before painting thereof;

• a table (70) for mounting said first and second cylinders (30, 40), said gear-box (50) connected to said electric motor (60) and said rotatable fixture (90); and

• an operator’s box (100) provided beside said table (70) for accommodating a control panel of said single touch ring gear sanding machine;

wherein said sanding unit (10) comprises an electronic control unit (ECU) having an electronic timer (ET) for adjusting cycle time thereof, depending on number of ring gears (80) to be sanded per cycle, said electronic control unit (ECU) and said load-cell (20) display fitted on said operator’s box (100).

2. Sanding machine as claimed in claim 1, wherein said sanding unit (10) is a linearly moving sanding unit comprising a sanding tool rotating at a speed varied from 1500 rpm to 2000 rpm.

3. Sanding machine as claimed in claim 1, wherein said load cell (20) is integrated with said sanding tool to continuously measure the load applied on said ring gears (80) during sanding thereof and to display on said electronic control unit (ECU) fitted on said operator’s box (100) and said load cell comprises digital display controller with load measuring capacity in the range of 0-10 kg.

4. Sanding machine as claimed in claim 1, wherein said first cylinder (30) is configured for vertical to-and-fro movement of said sanding unit (10) depending on the number of ring gears (80) loaded on said rotatable fixture (90) to be sanded per cycle.

5. Sanding machine as claimed in claim 4, wherein said first cylinder (30) is a pneumatic cylinder having a 300-1400 mm stroke.

6. Sanding machine as claimed in claim 1, wherein said second cylinder (40) is configured for clamping said sanding unit (10) to said ring gears (80) loaded on said rotatable fixture (90) and said second cylinder (40) is a pneumatic cylinder having a 15-35 mm stroke.

7. Sanding machine as claimed in claim 1, wherein said gear-box (50) is a low-speed gear-box to rotate said plurality of ring gears (80), said gear box is rotating at a speed varied from 15 rpm to 20 rpm.

8. Sanding machine as claimed in claim 1, wherein said electric motor (60) is a 3-phase induction motor.

9. Sanding machine as claimed in claim 1, wherein said sanding unit (10) is vertically moved multiple times to obtain targeted surface roughness (Ra) for subsequent painting operation on said ring gears (80).

10. An electronically-controlled, single-touch, multiple ring-gear sanding machine comprising:

• a linearly moving sanding unit (10) comprising a sanding tool rotating at a speed varied from 1500 rom to 2500 rpm;

• a load cell (20) integrated with said sanding unit (10) to continuously measure load applied on said ring gears (80) and display on a digital display controller; said load cell has a load capacity in a range of 0-20 kg;

• a first cylinder (30) configured as a pneumatic cylinder for vertical to-and-fro movement of said sanding unit (10), said pneumatic cylinder having about 500-800 mm stroke, based on the number of ring gears (80) to be sanded per cycle;

• a second cylinder (40) to operate said first cylinder (30) configured for clamping said sanding unit (10) to said ring gears (80), and having a 15-35 mm stroke;

• a gear-box (50) to rotate said plurality of ring gears (80) as well as to operate said second cylinder (40), said gear box rotating at a speed varied from 15 rpm to 20 rpm;

• a motor (60) for operating said gear box (50);

• a rotatable fixture (90) for stacked mounting of said ring gears (80) to be sanded before painting thereof;

• a table (70) for mounting said first and second cylinders (30, 40), said gear-box (50) connected to said motor (60) and said rotatable fixture (90); and

• an operator’s box (100) provided beside said table (70) for accommodating a control panel of said single touch ring gear sanding machine;

wherein said sanding unit (10) comprises an electronic control unit (ECU) having an electronic timer (ET) for adjusting cycle time thereof, depending on the number of ring gears (80) to be sanded per cycle, said electronic control unit (ECU) and said load-cell display fitted on said operator’s box (100); and wherein said sanding unit (10) is vertically moved to-and-fro multiple times depending on targeted surface roughness (Ra) for subsequent painting operation on said ring gears (80).

Digitally Signed.

Dated: this day of 31st October 2017. (SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT.