DESC:FIELD OF INVENTION
[001] The presently disclosed subject matter relates to an apparatus and a method for measuring span of a gear. Specifically, the presently disclosed subject matter relates to the apparatus and the method for measuring gear tooth span of spur gears automatically.
CROSS REFERENCE TO RELATED INVENTION
[002] This invention takes priority from an earlier filed provisional patent application no. 201921004984 filed on February 8, 2019; which is incorporated herein as reference.
BACKGROUND
[003] Gears are one of the common components of many machines. It is very important for a gear to be in good condition in order to optimize the quality of final output from the machine. Moreover, it is essential to check working condition of a gear on regular basis due to wear and tear.
[004] It is often required to measure gear span and calculate tooth thickness or gear pitch. Gear span can be defined as the distance across several teeth of gear in a normal plane. There are existing devices and/or methods for measuring gear span. For example, devices such as dial gauges and vernier calipers are available to measure the span. Similarly, there are existing methods such as the base tangent method and the like. It is reported that these devices and/or methods either need a lot of manual intervention or involve errors due to inaccurate calculations.
[005] Further, the process of checking value of gear tooth span manually by using contacting surface micrometer is error-prone and time-consuming. Referring to FIG. 1, the inspection method of checking span value at multiple positions (1, 2, 3, 4) of gear 33 having bore (33a) is not preferred due to time constraints and dependency on skill and memory of human operator to confirm the exact value and position. Other disadvantage of the manual techniques is the possible dent/damage of the equipment due to manual handling by human operator.
[006] Accordingly, there is a need for an improved device and a method to overcome the problems and measure the span of the gear with least manual intervention and calculations in an efficient manner.
SUMMARY OF THE INVENTION
[007] It is an object of the presently disclosed subject matter to overcome prior art sufferings and develop a new equipment/method for checking/measuring gear tooth span value which is automatic, precise, fast, reliable and flexible.
[008] According to another object of the presently disclosed subject matter, an apparatus and a method for measuring span of a gear is disclosed.
[009] According to another object of the presently disclosed subject matter, it refers to an apparatus for measuring span of the gear, the apparatus comprising:
a clamping unit for clamping the gear;
a driving unit for rotating the gear;
a moving unit movably mounted on a surface;
a measuring unit mounted on the moving unit and configured to measure span of the gear; and
a control unit configured to control the clamping unit, the driving unit, the moving unit and the measuring unit.
[0010] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear with minimal human intervention.
[010] It is yet another object of the present presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the clamping unit comprises a collet, a spring for holding the collet in its position, a clamp actuator for controlling the collet, a spindle shaft and a taper mandrel.
[011] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the driving unit is configured to rotate the gear to allow measurement of span at multiple angular positions.
[012] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein a sensor is used for detecting the angular position of the gear and indexing the gear.
[013] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the control unit is configured for controlling the driving unit based on the readings received from the sensor.
[014] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the measuring unit comprises a contact assembly and a probe unit.
[015] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the contact assembly comprises a first contacting member and a second contacting member configured to allow relative movement between them.
[016] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the first contacting member comprises a first contacting surface to touch tooth of the gear.
[017] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the second contacting member comprises a second contacting surface to touch tooth of the gear such that the distance between the first contacting surface and the second contacting surface is measured by the probe unit.
[018] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the probe unit is configured to measure the distance between the first contacting surface and the second contacting surface.
[019] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the driving unit is configured to rotate the gear to match orientation of teeth of the gear with the first contacting surface and the second contacting surface.
[020] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein an actuating means is configured to move the moving unit and the measuring unit.
[021] It is yet another object of the presently disclosed subject matter, wherein the actuating means is controlled by the control unit.
[022] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the control unit comprises a memory module configured to store span measurements of the gear at different angular positions.
[023] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein a man machine interface is configured to display the gear parameters comprising at least one of span values of the gear at different positions, maximum span value of the gear, minimum span value of the gear, condition of the gear or a combination thereof.
[024] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the control unit comprises at least one of a microprocessor, a microcontroller, a PLC unit, or a combination thereof.
[025] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein the probe unit (32) is selected from a group consisting of an LVDT probe and a laser sensor.
[026] It is yet another object of the presently disclosed subject matter to provide an apparatus for measuring span of the gear, wherein a robotic arm is used for loading and unloading of the gear on the table.
[027] It is yet another object of the presently disclosed subject matter to provide a method for measuring span of a gear, the method comprising:
clamping the gear by a clamping unit;
rotating the gear by a driving unit when the gear is in clamped position;
declamping the gear;
moving a measuring unit which is mounted on a moving unit towards the gear, wherein the moving unit is mounted on a surface;
measuring the span of the gear with the measuring unit; and
wherein a control unit is configured to control the clamping unit, the driving unit, the moving unit and the measuring unit.
[028] It is yet another object of the presently disclosed subject matter to provide a method for measuring span of the gear, wherein the driving unit is configured to rotate the gear and allow measurement of span of the gear at multiple angular positions.
[029] It is yet another object of the presently disclosed subject matter to provide a method for measuring span of the gear, wherein the measuring unit comprises a contact assembly and a probe unit.
[030] It is yet another object of the presently disclosed subject matter to provide a method for measuring span of the gear, wherein the contact assembly comprises a first contacting member and a second contacting member configured to allow relative movement between them.
[031] It is yet another object of the presently disclosed subject matter to provide a method for measuring span of the gear, wherein the first contacting member comprises a first contacting surface to touch tooth of the gear and the second contacting member comprises a second contacting surface to touch tooth of the gear such that distance between the first contacting surface and the second contacting surface is measured by the probe unit.
[032] It is yet another object of the presently disclosed subject matter to provide a method for measuring span of the gear, wherein the moving unit and the measuring unit are moved by an actuating means controlled by the control unit.
[033] It is yet another object of the presently disclosed subject matter to provide an apparatus and a method for automatic measurement of gear tooth span.
[034] It is yet another object of the invention, wherein the clamp actuator is selected from a group consisting of a hydraulic cylinder, a pneumatic cylinder and a motor.
[035] It is yet another object of the invention, wherein the driving unit is selected from a group consisting of a servo motor, a stepper motor, a DC motor, a synchronous motor, an induction motor, a hydraulic motor and a pneumatic motor.
[036] It is yet another object of the invention, wherein the gear is configured to rotate at an angle varying from 5 to 200 degrees.
Automatic measurement according to the apparatus/method described in one or more embodiments/steps of the present invention can be enabled using a combination of control unit and software along with other necessary components.
The summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
DESCRIPTION OF DRAWINGS
In order to understand the invention and to see how it can be carried out in practice, non-limiting examples and embodiments will now be described with reference to the accompanying drawings, in which:
[037] FIG. 1 illustrates a manual method from prior art for checking of gear tooth span value by using contacting surface micrometer;
[038] FIG. 2 illustrates an isometric view of the apparatus for measuring span of the gear according to an embodiment of the invention;
[039] FIG. 3 illustrates an exploded view of the clamping unit according to another embodiment of the invention;
[040] FIG. 4 illustrates a sectional view of the apparatus according to another embodiment of the invention;
[041] FIG. 5A illustrates a sectional view of the clamping unit showing gear in a clamped position;
[042] FIG. 5B illustrates a sectional view of the clamping unit showing gear in a declamped position;
[043] FIG. 6 illustrates a sectional view of the apparatus showing the measuring unit;
[044] FIG. 7 illustrates a method for measuring span of the gear according to another embodiment of the invention;
[045] FIG. 8 illustrates a top view of the apparatus; and
[046] FIG. 9A to FIG. 9D illustrates the top view of the apparatus showing the gear at 4 different angular positions.
DETAILED DESCRIPTION OF THE INVENTION
[047] All the aspects described herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred aspects and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope herein without departing from the spirit and scope thereof, and the present invention herein includes all such modifications.
[048] FIG. 2 shows an apparatus (10) for measuring span of a gear (33) according to an embodiment of the invention. The apparatus (10) comprises a clamping unit (20) for clamping the gear (33); a driving unit (35) for rotating the gear (33); a moving unit (36) movably mounted on a surface (11); a measuring unit (30) mounted on the moving unit (36) and configured to measure span of the gear (33); and a control unit (50) configured to control the clamping unit (20), the driving unit (35), the moving unit (36) and the measuring unit (30).
[049] The gear can be a spur gear, a helical gear, a bevel gear, a spiral bevel Gear, a screw gear, a miter gear or any other gear known in the art. The apparatus (10) measures the span of the gear (33) at multiple angular positions.
[050] FIG. 3 illustrates an exploded view of the clamping unit (20) according to another embodiment of the invention. The clamping unit (20) comprises a rest pad (23) for supporting the gear (33) on the surface (11) in clamped/declamped position. The Clamping unit (20) further comprises a collet (22) having collet fingers (not shown), configured to clamp bore of the gear (33). The clamping unit (20) further comprises a taper mandrel (39) having a first end (391) and a second end (392). The first end (391) of the taper mandrel (39) is inserted into the collet (22) and the second end (392) of the taper mandrel (39) is connected to a spindle shaft (21). The spindle shaft (21) provides movement to the taper mandrel (39) in upward and downward directions, wherein the movement of the taper mandrel (39) in vertically-downward direction pushes the collet fingers of the collet (22) on the inner surface of bore of the gear (33) and clamps the gear (33). It is to be understood that other suitable means for clamping the gear (33) obvious to a person skilled in the art, can also be used without departing from the scope and spirit of the invention.
[051] The spindle shaft (21) comprises a top end (211) connected to the second end (392) of the taper mandrel (39) and a bottom end (212) connected a clamp actuator (34) as shown in FIG. 4. The clamp actuator (34) pushes the spindle shaft (21) upwards for declamping the gear (33). Further, a disc spring (24) is attached to the spindle shaft (21) near the bottom end (212) of the spindle shaft (21).
[052] According to a preferred embodiment of the invention, a pneumatic cylinder is used as the clamp actuator (34). However, other suitable means, for example, motor or hydraulic cylinder can also be used.
[053] The working of the clamping and declamping mechanism is as following:
a. The clamping unit (20) is in declamped position when the gear (33) is not loaded on the surface (11). The clamp actuator (34) provides the force for holding the spindle shaft (21) in upwards position. In this position, the disc spring (24) is in the compressed state due to the force provided by the clamp actuator (34).
b. When the gear (33) is loaded on the surface (11) for clamping, the clamp actuator (34) is deactivated which removes the force from the spindle shaft (21). This results in the expansion of compressed disc spring (24) and the expansion force thereof pulls the spindle shaft (21) downwards, thus clamping the gear (33).
c. When it is required to declamp the gear, the clamp actuator (34) is again activated which pushes the spindle shaft (21), thus again compressing the disc spring (24) and declamping the gear (33).
[054] FIG. 5A illustrates the gear (33) in the clamped position when the spindle shaft (21) is pulled downwards by the disc spring (24). FIG. 5B illustrates the gear (33) in declamped position when the spindle shaft (21) is pushed upwards by the clamp actuator (34).
[055] Referring to FIG. 3, a bearing housing (25) comprises a plurality of bearings for supporting the spindle shaft (21)
[056] In yet another embodiment of the invention, the disc spring (24) is attached between the bottom end (212) of the spindle shaft (21) and the clamp actuator (34). The pull and push forces on the spindle shaft (21) are provided by the clamp actuator (34). Further, other suitable means for pulling/pushing the spindle shaft (21) obvious to a person skilled in the art, can also be used.
[057] The spindle shaft (21) also rotates the gear (33) and changes the angular position of the gear (33) when the gear (33) is clamped by the collet (22). This solves the purpose of measurement of span of the gear (33) at multiple angular positions.
[058] Referring to FIG. 4, the spindle shaft (21) is configured to move in downward/upward directions for clamping/declamping the gear (33) and to rotate the clamped gear (33) by the driving unit (35).
[059] The driving unit (35) comprises an output shaft (351) coupled to the spindle shaft (21). Any of the assembly, for example a pulley assembly, gear assembly, friction cylinders assembly, etc, already known in the art can be used to couple the output shaft (351) of the driving unit (35) with the spindle shaft (21).
[060] According to still another embodiment of the invention, a servo motor is used as driving unit (35). However, other suitable means, for example, a stepper motor, a DC motor, a synchronous motor, an induction motor, a hydraulic motor and a pneumatic motor obvious to a person skilled in the art, can also be used.
[061] A sensor (41) is positioned to detect the angular position of the gear (33) as shown in FIG. 4. According to another preferred embodiment of the invention, the sensor (41) is an analog sensor. The driving unit (35) rotates the gear (33) and the sensor (41) measure the angular position of the gear (33) for indexing of the gear (33). The sensor (41) and the driving unit (35) work synchronously to provide an arrangement to rotate the gear and solve the purpose of measurement of span of the gear (33) at multiple angular positions.
[062] According to another embodiment of the invention, any sensor used for detecting position of the gear (33) for example a digital sensor, Capacitive displacement sensor, Eddy-current sensor, Hall effect sensor, magnetic sensors ,Inductive sensor, Laser Doppler vibrometer, Linear variable differential transformer (LVDT), Photodiode array, Piezo-electric transducer, Position encoders, Absolute encoder, Incremental encoder, Linear encoder, Rotary encoder, Potentiometer, Proximity sensor, String potentiometer (also known as string pot., string encoder, cable position transducer), Ultrasonic sensor obvious to a person skilled in the art, can also be used
[063] Referring to FIG. 2, the moving unit (36) is mounted on the surface (11) such that the moving unit (36) can smoothly move on the surface (11) along the y-axis. According to yet another preferred embodiment of the invention, the moving unit (36) is mounted on the surface (11) by rails (51), however, other suitable means obvious to a person skilled in the art, can also be used. Further, the actuating means (31) is mounted on the surface (11) and connected to the moving unit (36) for moving the moving unit (36) along the y-axis.
[064] According to yet another embodiment of the invention, a pneumatic cylinder is used as the actuating means (31), however, other suitable means for example motor, hydraulic cylinder obvious to a person skilled in the art, can also be used.
[065] The measuring unit (30) for measuring span of the gear (33) is mounted on the moving unit (36) such that the moving unit (36) moves the measuring unit (30) towards the gear (33) and away from the gear (33). As shown in FIG. 2 and FIG. 6, the measuring unit (30) comprises a contact assembly (40) and a probe unit (32). The contact assembly (40) further comprises a first contacting member (37) and a second contacting member (38). The first contacting member (37) and the second contacting member (38) are mounted on the moving unit (36) such that there is relative movement between them along the x-axis.
[066] According to yet another embodiment of the invention, the first contacting member (37) is a first anvil and the second contacting member (38) is a second anvil, however, other suitable members for example blocks, chucks, jaws, mandrels, arbors, solid shafts, hollow shafts obvious to a person skilled in the art, can also be used as respective contact members.
[067] According to yet another embodiment of the invention, the first contacting member (37) and the second contacting member (38) are mounted on the moving unit (36) along the same axis.
[068] The first contacting member (37) comprises a front end and a rear end, as shown in FIG. 6. The front end of the first contacting member (37) is located close to the gear (33) and the rear end of the first contacting member (37) is located away from the gear (33). Similarly, the second contacting member (38) comprises a front end and a rear end, the front end of the second contacting member (38) is located close to the gear (33) and the rear end of the first contacting member (38) is located away from the gear (33). The contact assembly (40) further comprises a first contacting surface (42) located at the front end of the first contacting member (37) and a second contacting surface (43) located at the front end of the second contacting member (38).
[069] According to another embodiment of the invention, the first contacting member (37) and the second contacting member (38) are mounted on the moving unit (36) such that both first contacting member (37) and the second contacting member (38) can move independently along the x-axis.
[070] The actuating means (31) is connected to the first contacting member (37) and the second contacting member (38) for moving the first contacting member (37) and the second contacting member (38) towards the gear (33) to touch the first contacting surface (42) and the second contacting surface (43) with teeth of the gear (33). The probe unit (32) is mounted on the moving unit (36) for measuring the distance between the first contacting surface (42) and the second contacting surface (43).
[071] In another preferred embodiment of the invention, one actuating means (31) is configured to move the moving unit (36), the first contacting member (37) and the second contacting member (38).
[072] According to another embodiment of the invention, the apparatus (10) comprises three actuating means, a first actuating means for moving the moving unit (36), a second actuating means for moving the first contacting member (37) and a third actuating means for moving the second contacting member (38).
[073] According to yet another embodiment of the invention, the apparatus (10) comprises two actuating means, a first actuating means for moving the moving unit (36) and a second actuating means for moving the first contacting member (37) and the second contacting member (38).
[074] According to another embodiment of the invention, the first contacting member (37) is mounted on the moving unit (36) such that the first contacting member (37) is movable along x-axis relative to the moving unit (36), whereas the second contacting member (38) is fixed on the moving unit (36). For measuring the span of the gear (33), the moving unit (36) is moved towards the gear (33), resulting in the second surface (43) to be in contact with tooth of the gear (33). After complete movement of the moving unit (36) towards the gear (33), the first contacting member (37) is moved towards the gear (33) to touch the first contacting surface (42) with tooth of the gear (33).
[075] According to another embodiment of the invention, the probe unit (32) comprises a first probe (321) and a second probe (322) as shown in FIG. 6. The first probe (321) is mounted on the moving unit (36), positioned near the rear end of the first contacting member (37). Similarly, a second probe (322) is mounted on the moving unit (36), positioned near the rear end of the second contacting member (38). The first probe (321) and the second probe (322) measure distance between the first contacting surface (42) and the second contacting surface (43), when the first contacting surface (42) and the second contacting surface (43) touch teeth of the gear (33), thus measuring the span of the gear (33).
[076] According to a preferred embodiment of the invention, the first probe (321) and the second probe (322) are LVDT (Linear Variable Differential Transformer) probes.
[077] According to another embodiment of the invention, when the second contacting member (38) is fixed on the moving unit (36), the probe unit (32) comprises of a single LVDT probe (321) mounted on the moving unit (36), positioned near the rear end of the first contacting member (37) for measuring the distance between the first contacting surface (42) and the second contacting surface (43).
[078] According to yet another embodiment of the invention, the probe unit (32) comprises a laser sensor mounted at the front end of the first contacting member (37) for measuring the distance between the first contacting surface (42) and the second contacting surface (43).
[079] According to yet another embodiment of the invention, the probe unit (32) comprises of a laser sensor mounted at the front end of the second contacting member (38) for measuring the distance between the first contacting surface (42) and the second contacting surface (43).
[080] Apart from the above-mentioned arrangements, any arrangement of distance measuring sensors already known in the art can be used as the probe unit (32) for measuring the distance between the first contacting surface (42) and the second contacting surface (43).
[081] According to another embodiment of the invention, a first flange is mounted on the front end of the first contacting member (37) and a second flange is mounted on the front end of the second contacting member (37) to provide the first contacting surface (42) and the second contacting surface (43).
[082] According to another embodiment of the invention, the front end of the first contacting member (37) and the front end of the second contacting member (38) are themselves designed as a balls, measuring wedges, knife edges etc and solve the purpose of the first contacting surface (42) and the second contacting surface (43).
[083] According to another embodiment of the invention, the control unit (50) is configured to control the clamp actuator (34), the driving unit (35) and the actuating means (31). The control unit (50) is further configured to receive angular position measurements from the sensor (41) and distance measurements from the probe unit (32). The control unit (50) comprises at least one of a microprocessor, a microcontroller, a PLC unit, a CPU or a combination thereof.
[084] As shown in FIG. 4, the control unit (50) controls the clamp actuator (34) and rotates the driving unit (35) based on the angular position measured by the sensor (41). The control unit (50) comprises a memory module configured to store span measurements of the gear (33) at different angular positions. The control unit (50) automates operation of the apparatus (10) by controlling various units using software or set of instructions stored in the memory module.
[085] According to an exemplary embodiment of the invention, the control unit (50) comprises a specific microprocessor specifically configured/trained to control various units of apparatus (10) and thus automating the method for measuring the span of the gear (33).
[086] According to another embodiment of the invention, the control unit (50) comprises a monitoring module configured to monitor one or more operational characteristics of the apparatus (10).
[087] According to another embodiment of the invention, the control unit (50) comprises a communication module to enable the communication of the control unit (50) with other external devices.
[088] According to another embodiment of the invention, the control unit (50) comprises a calculation module to calculate other gear parameters such as gear pitch, tooth thickness, condition of the gear, etc based on the measured span value. These calculated values can be stored in the memory module.
[089] The control unit (50) further comprises a display unit or a man machine interface configured to display different gear parameters. The gear parameters can be span values of the gear (33) at different positions, maximum span value of the gear (33), minimum span values of the gear (33) and/or condition of the gear (33). For example, display units, such as, but not limited to, conventional screen/monitor, liquid crystal display, LED display, or dot-matrix visual display can be used. Further, the man machine interface can be capable of presenting text, images, icons, graphic data and other information,
[090] FIG. 7 illustrates the method (700) for measuring span of the gear (33) according to another embodiment of the invention. As shown at S701, the gear (33) is loaded on the surface (11) by an operator or by a robotic arm.
[091] After loading the gear (33) on the surface (11), the gear (33) is clamped on the surface (11) by the clamping unit (20) as indicated at S702. The sensor (41) measures the angular position of the gear (33) and sends measurements to the control unit (50). Based on angular position measurements received from the sensor (41), the control unit (50) rotates the gear as indicated at S703. The gear (33) is rotated to match the orientation of teeth of the gear (33) with the first contacting surface (42) and the second contacting surface (43).
[092] When the desired angular position is achieved, the control unit (50) triggers the clamp actuator (34) to declamp the gear (33) as indicated at S704.
[093] After the gear (33) is declamped, the control unit (50) triggers the actuating means (31) to move the moving unit (36) towards the gear (33). When the moving unit (36) is at the desired position, the control unit (50) triggers the actuating means (31) to move the first contacting member (37) and the second contacting member (38) towards the gear (33) as indicated at S706. The first contacting member (37) and the second contacting member (38) are moved till the first contacting surface (42) and the second contacting surface (43) touch the teeth of the gear (33). The first contacting member (37) and the second contacting member (38) can be moved by the actuating means (31) towards the gear (33) according to another embodiment of the invention. According to the still another embodiment, only the first contacting member (37) is moved towards the gear (33) by the actuating means (31) described above.
[094] As is indicated at S707, when the first contacting surface (42) and the second contacting surface (43) touch the teeth of the gear (33), the distance between the first contacting surface (42) and the second contacting surface (43) is measured by the probe unit (32) and the measured distance is sent to the control unit (50). The control unit (50) stores the span measurements at that particular angular position in the memory.
[095] After the measured distance reading is sent to the control unit (50), the control unit (50) triggers the actuating means (31) to retract the moving unit (36), the first contacting member (37) and the second contacting member (38) away from the gear, as indicated at S708.
[096] After the moving unit (36) is fully retracted, the control unit (50) will check if another reading is required or not. If the desired number of readings has already been taken, the control unit (50) ends the process and the gear (33) is unloaded from the surface (11). The gear (33) can be unloaded from the surface (11) by the operator or by a robotic arm. If it is required to take another reading, the control unit (50) again repeats the method and perform steps from S702 to S708
[097] FIG. 8 shows the top views of the apparatus (10) with the gear (33) clamped on the surface (11). FIG. 9A to FIG. 9D shows the gear (33) at 4 different angular positions. Markings 1, 2, 3, 4 are marked on the gear (33) to display the angular position of the gear (33). As shown in FIG. 9A, the gear (33) is in a first position to measure span of the gear (33) at the position 1. When the span is measured, the gear (33) is rotated by 90 degrees to measure the span of the gear (33) at position 2, as shown in FIG. 9B. When the span has been measured at position 2, the gear (33) is further rotated to a third position to measure span at position 3 as shown in FIG. 9C and similarly to a fourth position to measure span at position 4 as shown in FIG. 9D. Once all readings are taken, the gear (33) is unloaded from the apparatus and the gear parameters are displayed on the man machine interface.
[098] Similarly, readings at multiple angular positions can be taken by above mentioned mechanism. The gear (33) is rotated by an angle based on the number of readings required to be taken. The driving unit (35) can rotate the gear (33) by an angle varying from 5 degrees to 200 degrees depending on the number of reading.
[099] As shown in FIG. 7 and FIG. 8, the span of the gear (33) is measured automatically by the apparatus (10) without any human intervention. The control unit (50) controls the various units for performing span measurement and the set of instructions for automatically controlling the various units are stored in the memory module of the control unit (50). This automatic span measurement reduces time and increases the accuracy of the span measurement process.
[0100] Although the invention has been described with regard to its embodiments, specific embodiments, and various examples, which constitute the best mode presently known to the inventors, it should be understood that various changes and modifications as would be obvious to one having the ordinary skill in this art may be made without departing from the scope of the invention. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. All changes that come with meaning and range of equivalency of the claims are to be embraced within their scope.
,CLAIMS:1. An apparatus (10) for measuring span of a gear (33), the apparatus (10) comprising:
a clamping unit (20) for clamping the gear (33);
a driving unit (35) for rotating the gear (33);
a moving unit (36) movably mounted on a surface (11);
a measuring unit (30) mounted on the moving unit (36) and configured to measure span of the gear (33); and
a control unit (50) configured to control the clamping unit (20), the driving unit (35), the moving unit (36) and measuring unit (30).
2. The apparatus (10) according to claim 1, wherein the clamping unit (20) comprises a collet (22), a spring (24) for holding the collet (22) in its position, a clamp actuator (34) for controlling the collet (22), a spindle shaft (21) and a taper mandrel (39).
3. The apparatus (10) according to claim 1, wherein the driving unit (35) is configured to rotate the gear (33) and allow measurement of span of the gear (33) at multiple angular positions.
4. The apparatus (10) according to claim 1, wherein the apparatus (10) comprises a sensor (41) for detecting angular position of the gear (33).
5. The apparatus (10) according to claim 4, wherein the control unit (50) is configured to control the driving unit (35) based on detection of angular position from the sensor (41).
6. The apparatus (10) according to claim 1, wherein the measuring unit (30) comprises a contact assembly (40) and a probe unit (32).
7. The apparatus (10) according to claim 6, wherein the probe unit (32) is selected from a group consisting of an LVDT probe and a laser sensor.
8. The apparatus (10) according to claim 6, wherein the contact assembly (40) comprises a first contacting member (37) and a second contacting member (38) configured to allow relative movement between them.
9. The apparatus (10) according to claim 8, wherein the first contacting member (37) comprises a first contacting surface (42) to touch tooth of the gear (33) and the second contacting member (38) comprises a second contacting surface (43) to touch tooth of the gear (33) such that the distance between the first contacting surface (42) and the second contacting surface (43) is measured by the probe unit (32).
10. The apparatus (10) according to claim 1, wherein the driving unit (35) is configured to rotate the gear (33) to match orientation of teeth of the gear (33) with the first contacting surface (42) and the second contacting surface (43).
11. The apparatus (10) according to claim 1, wherein the moving unit (36) and the measuring unit (30) are moved by an actuating means (31) controlled by the control unit (50).
12. The apparatus (10) according to claim 1, wherein the control unit (50) comprises a memory module configured to store span measurements of the gear (33) at different angular positions.
13. The apparatus (10) according to claim 1, wherein the control unit comprises at least one of a microprocessor, a microcontroller, a PLC unit, a CPU or a combination thereof.
14. The apparatus (10) according to claim 1, further comprises a man machine interface configured to display measured gear parameters.
15. A method for measuring span of a gear (33), the method comprising:
clamping the gear (33) by a clamping unit (20);
rotating the gear (33) by a driving unit (35) when the gear (33) is in clamped position;
declamping the gear (33);
moving a measuring unit (30), which is mounted on a moving unit (36), towards the gear (33), wherein the moving unit (36) is mounted on a surface (11);
measuring the span of the gear (33) with the measuring unit (30);
wherein a control unit (50) is configured to control the clamping unit (20), the driving unit (35), the moving unit (36) and measuring unit (30).
16. The method according to claim 15, wherein the driving unit (35) is configured to rotate the gear (33) and allow measurement of span of the gear (33) at multiple angular positions.
17. The method according to claim 15, wherein the measuring unit (30) comprises a contact assembly (40) and a probe unit (32).
18. The method according to claim 16, wherein the contact assembly (40) comprises a first contacting member (37) and a second contacting member (38) configured to allow relative movement between them.
19. The method according to claim 17, wherein the first contacting member (37) comprises a first contacting surface (42) to touch tooth of the gear (33) and the second contacting member (38) comprises a second contacting surface (43) to touch tooth of the gear (33) such that distance between the first contacting surface (42) and the second contacting surface (43) is measured by the probe unit (32).
20. The method according to claim 15, wherein the moving unit (36) and the measuring unit (30) are moved by an actuating means (31) controlled by the control unit (50).