DESC:TECHNICAL FIELD
[001] The embodiments herein relate to an automatic tool changer system for a machine and a method of operating an automatic tool changer in the machine.

BACKGROUND
[002] Generally, an automatic tool changer (hereinafter referred to as ATC) is used in computerized numerical control (hereinafter referred to as CNC) machines to improve the production and tool carrying capacity of the CNC machine to work with a number of tools. The ATC changes the tool very quickly which in turn reduces the non-productive time. In some cases, ATC is also used to change worn out or broken tools from the CNC machines. Usually, the ATC is moved through a hydraulic motor to remove and insert tool(s) with respect to a machine spindle and a tool magazine. A splined shaft of the hydraulic motor is coupled to the ATC. The hydraulic motor is subjected to frequent premature failure, in which a helical geared piston shaft provided inside the hydraulic motor is subjected to wear and tear of gear teeth, and contaminants get accumulated at hydraulic reservoir and manifold block which in turn leads to failure of hydraulic valves, choking of filters and punctures in accumulator bladder. The frequent failure of the hydraulic motor would lead to higher break down time of the ATC which in turn results in reduced production. Further, the hydraulic motor is complex in design and the frequent premature failures of the hydraulic motor would require replacement of the hydraulic motor with a new hydraulic motor for effective functioning of the ATC. However, the replacement of the hydraulic motor with the new hydraulic motor is costly and effects the running cost of line.
[003] Therefore, there exists a need for an automatic tool changer system and a method of operating an automatic tool changer in a machine, which obviates the aforementioned drawbacks.

OBJECTS
[004] The principal object of embodiments herein is to provide an automatic tool changer system for a machine.
[005] Another object of embodiments herein is to provide a method of operating an automatic tool changer in a machine.
[006] Another object of embodiments herein is to provide an electro-mechanical automatic tool changer system for a machine.
[007] Another object of embodiments herein is to provide an automatic tool changer system for a machine, which is adapted to transport tool(s) between a tool magazine (magazine area) and a machine spindle (machining area).
[008] Another object of embodiments herein is to provide an automatic tool changer system for a machine, which is adapted to restrict a movement of an automatic tool changer at tool change positions against reaction force exerted during removal and insertion of tool(s) with respect to a tool magazine and a machine spindle.
[009] Another object of embodiments herein is to provide an automatic tool changer system for a machine, which changes tool within standard tool change time.
[0010] Another object of embodiments herein is to provide an automatic tool changer system for a machine, which is reliable and incurs less investment and maintenance costs.
[0011] Another object of embodiments herein is to provide an automatic tool changer system, which can be retrofitted to an automatic tool changer and provided in communication with a machine.
[0012] These and other objects of embodiments herein will be better appreciated and understood when considered in conjunction with following description and accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments 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 of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0013] The embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0014] Fig. 1 depicts a schematic diagram of an automatic tool changer system for a machine, according to embodiments as disclosed herein;
[0015] Fig. 2 depicts a cross-sectional view of the power transmission unit with a second coupling flange secured thereon, according to embodiments as disclosed herein;
[0016] Fig. 3 depicts a perspective view of a reduction gear rotatably connected with an input shaft of the power transmission unit, according to embodiments as disclosed herein;
[0017] Fig. 4 depicts a front view of a first coupling flange, according to embodiments as disclosed herein; and
[0018] Fig. 5 depicts a flowchart indicating a method of operating an automatic tool changer in the machine, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[0019] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed 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.
[0020] The embodiments herein achieve an automatic tool changer system for a machine. Further, embodiments herein achieve a method of operating an automatic tool changer in a machine. Further, embodiments herein achieve an automatic tool changer system, which is adapted to transport tool(s) between a tool magazine (magazine area) and a machine spindle (machining area) and to restrict a movement of the automatic tool changer at tool change positions against reaction force exerted during removal and insertion of tool(s) with respect to the tool magazine and the machine spindle. Referring now to the drawings Figs 1 through Fig. 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0021] Fig. 1 depicts a schematic diagram of an automatic tool changer system (100) for a machine, according to embodiments as disclosed herein. The automatic tool changer system (100) is adapted to transport tool(s) between a tool magazine (magazine area) and a machine spindle (machining area) and to restrict a movement of the automatic tool changer (10) at tool change positions against reaction force exerted during removal and insertion of tool(s) with respect to the tool magazine (not shown) and the machine spindle (not shown). In an embodiment, the automatic tool changer system (100) includes an automatic tool changer (10), a power transmission unit (102), a first coupling flange (103), a motor (104), a second coupling flange (105), a controller unit (106) and a plurality of presence detecting sensors (not shown). For the purpose of this description and ease of understanding, the automatic tool changer system (100) is explained herein with below reference to moving the automatic tool changer (10) between the tool magazine (not shown) and a computerized numerical control (hereinafter referred to as CNC) machine such as horizontal machining centers (hereinafter referred to as HMC). However, it is also within the scope of this invention to practice/implement the automatic tool changer system (100) for moving the automatic tool changer between the tool magazine and vertical machining centers or any other metal working machines or any other type of CNC machines or any other automatic machining machines, where tool change is required by the machine, without otherwise deterring the intended function of the automatic tool changing system (100) as can be deduced from the description and corresponding drawings.
[0022] The automatic tool changer (10) is adapted to transport tool(s) between the tool magazine (not shown) and the machine spindle (not shown). For example, the automatic tool changer (10) is adapted to remove a buffer tool (not shown) from the tool magazine (not shown) and transports the buffer tool (not shown) to the machine spindle (not shown). Thereafter, the automatic tool changer (10) replaces the working tool (not shown) with the buffer tool (not shown) in the machine spindle (not shown) by removing the working tool (not shown) from the machine spindle (not shown) and inserting the buffer tool (not shown) to the machine spindle (not shown). Thereafter, the automatic tool changer (10) transports the removed tool (not shown) from the machine spindle (not shown) to the tool magazine (not shown) and inserts the tool (not shown) to the tool magazine (not shown). The automatic tool changer (10) mainly includes a movable member (not shown), a tool changer slide (12), a tool changer arm (14), a linear motor (LM) rail (16) and a tool gripper (18). For the purpose of this description and ease of understanding, the movable member (not shown) of the automatic tool changer (10) is considered to be a movable shaft. The movable member (not shown) of the automatic tool changer (10) is rotatably coupled to the tool changer slide (12).
[0023] Fig. 2 depicts a cross-sectional view of the power transmission unit (102) with the second coupling flange (105) secured thereon, according to embodiments as disclosed herein. Fig. 3 depicts a perspective view of a reduction gear (102G) rotatably connected with an input shaft (102S) of the power transmission unit (102), according to embodiments as disclosed herein. In an embodiment, the power transmission unit (102) is adapted to be driven by the motor (104) and the power transmission unit (102) in turn drives the movable member (not shown) of the automatic tool changer (10) therein to move the automatic tool changer (10) between the tool magazine (not shown) and the machine spindle (not shown) to enable the automatic tool changer (10) to remove and insert tool(s) with respect to the machine spindle (not shown) and the tool magazine (not shown). In an embodiment, the power transmission unit (10) is adapted to increase the braking torque of the motor (104) and transmits required braking torque to the automatic tool changer (10) therein to lock the automatic tool changer (10) thereby restricting a movement of the automatic tool changer (10) at tool change positions. The power transmission unit (102) is coupled to the automatic tool changer (10) and the motor (104). The power transmission unit (102) is mounted to the automatic tool changer (10) through the first coupling flange (103). The power transmission unit (102) is adapted to be driven by the motor (104) at required frequency through the controller unit (106). In an embodiment, the power transmission unit (102) mainly includes an input shaft (102S), as shown in fig. 2 and fig. 3), at least one reduction gear (102G), as shown in fig. 2 and fig. 3), an output shaft (102P), a transmission housing (102H), oil seals (102N) and bearings (102BR). The input shaft (102S) of the power transmission unit is coupled with a shaft (104S), as shown in fig. 1) of the motor (104). The input shaft (102S) is rotatably connected with the reduction gear (102G). For the purpose of this description and ease of understanding, the input shaft (102S) is considered to be a worm shaft. It is also within the scope of this invention to consider the input shaft (102S) as any other type of shaft corresponding to the type of reduction gear used in the power transmission unit (102). The input shaft (102S) is transverse to the output shaft (102P) of the power transmission unit (102) and the movable member (not shown) of the automatic tool changer (10). The reduction gear (102G) is rotatably connected with the output shaft (102P) and the input shaft (102S). For the purpose of this description and ease of understanding, the reduction gear (102G) is considered to be a worm gear. However, it is also within the scope of this invention to provide any other type of reduction gears or any other type of gears or spur gear train, helical gear train or planetary gear train or any other gear trains without otherwise deterring the intended function of the reduction gear (102G) as can be deduced from the description and corresponding drawings. The output shaft (102P) is coupled with the movable member (not shown) of the automatic tool changer (10). The output shaft (102P) is rotatably connected with the reduction gear (102G). The output shaft (102P) is a splined shaft. The output shaft (102P) of the power transmission unit (102) is co-axial to the movable member (not shown) of the automatic tool changer (10) and transverse to the input shaft (102S) of the power transmission unit (102). The transmission housing (102H) is adapted to house the input shaft (102S), the reduction gear (102G), bearings (102BR) and a portion of the output shaft (102P). The oil seals (102N) are adapted to retain the oil provided inside the power transmission unit (102).
[0024] In an embodiment, the gear ratio of the power transmission unit (102) is at least 20:1. For example, the power transmission unit (102) is adapted to increase the braking torque value of the motor (104) by 20 times and transmits required brake torque to the automatic tool changer (10) therein to restrict a movement of the automatic tool changer (10) at tool change positions. However, it is also within the scope of this invention to provide the power transmission unit (102) with any other gear ratios, where moving of automatic tool changer and locking of automatic tool changer by providing braking torque to the automatic tool changer through power transmission unit (102) is required in accordance to the type and configuration of automatic tool changer and machine, without otherwise deterring the intended function of the power transmission unit (102) as can be deduced from the description and corresponding drawings.
[0025] In an embodiment, the power transmission unit (102) is at least a reduction worm gearbox with 90 degree input worm shaft (102S) and output shaft (102P) to accommodate the space constraint in the power transmission unit (102). However, it is also within the scope of this invention to provide any other type of reduction gearboxes or any other configurations of gearboxes, where moving of automatic tool changer and locking of automatic tool changer by providing braking torque to the automatic tool changer through power transmission unit (102) is required, without otherwise deterring the intended function of the power transmission unit (102) as can be deduced from the description and corresponding drawings. The power transmission unit (102) is transverse to the movable member (not shown) of the automatic tool changer (10).
[0026] Fig. 4 depicts a front view of a first coupling flange (103), according to embodiments as disclosed herein. In an embodiment, the first coupling flange (103) is adapted to mount the power transmission unit (102) to the automatic tool changer (10). One end of the first coupling flange (103) is fastened to the power transmission unit (102) and another end of the first coupling flange (103) is fastened to the automatic tool changer (10) therein to secure the power transmission unit (102) with the automatic tool changer (10). The first coupling flange (103) includes a body (103B), a first flange (103F) and a second flange (103S). The first flange (103F) is adapted to radially extend from the corresponding end of the body (103B) in an outward direction. The first flange (103F) defines a plurality of fastener receiving portions (103X) adapted to receive fasteners (not shown) therethrough to secure the first coupling flange (103) with the power transmission unit (102). The first flange (103F) is parallel and opposite to the second flange (103S). The second flange (103S) is adapted to radially extend from the corresponding another end of the body (103B) in an outward direction. The second flange (103S) defines a plurality of fastener receiving portions (103Y) adapted to receive another fasteners (not shown) therethrough to secure the power transmission unit (102) with the automatic tool changer (10).
[0027] In an embodiment, the motor (104) is adapted to drive the automatic tool changer (10) through the power transmission unit (102) therein to move the automatic tool changer (10) between the tool magazine (not shown) and the machine spindle (not shown) to enable the automatic tool changer (10) to remove and insert tool(s) with respect to the machine spindle (not shown) and the tool magazine (not shown). In an embodiment, the motor (104) is adapted to provide braking torque to the automatic tool changer (10) through the power transmission unit (102) therein to restrict the movement of the automatic tool changer (10) at tool change positions. The motor (104) is coupled to the power transmission unit (102). The motor (104) includes a shaft (104S) and a brake unit (104B) adapted to be mounted onto corresponding end of the shaft (104S). However, it is also within the scope of the invention to provide the brake unit external to the motor (104) without otherwise deterring the intended function of the brake unit (104B) as can be deduced from the description and corresponding drawings. The shaft (104S) of the motor (104) is coupled with the input shaft (102S) of the power transmission unit (102). The brake unit (104B) is adapted to provide braking torque to the automatic tool changer (10) through the power transmission unit (10). For the purpose of this description and ease of understanding, the brake unit (104B) is considered to be a disc brake. However, it is also within the scope of this invention to provide any other type of brake units, where restriction of rotation of the shaft (104S) to provide braking torque to the automatic tool changer (10) through the power transmission unit (102) is required, without otherwise deterring the intended function of the brake unit (104B) as can be deduced from the description and corresponding drawings. The motor (104) is mounted to the power transmission unit (102) through the second coupling flange (105). The motor (104) is provided in communication with the controller unit (106). For the purpose of this description and ease of understanding, the motor (104) is considered to be at least an induction brake motor. However, it is also within the scope of this invention to provide any other type of motors for driving the automatic tool changer (10) through the power transmission unit (102), locking the automatic tool changer (10) at tool change positions by providing braking torque to the automatic tool changer (10) and operating in conjunction with the controller unit (106) is required, without otherwise deterring the intended function of the motor (104) as can be deduced from the description and corresponding drawings.
[0028] The motor (104) is adapted to move the automatic tool changer (10) between tool change positions at desired speed (rpm) by controlling the frequency of current to the motor (104) through the controller unit (106). The motor (104) includes a brake unit (104B) adapted to engage the shaft (104S, as shown in fig. 1) of the motor (104) therein to restrict the rotation of the shaft (104S) of the motor (104) to lock the automatic tool changer (10) at tool change positions by providing braking torque to the automatic tool changer (10) through the power transmission unit (102). The braking torque of the motor (104) is increased to required value through the power transmission unit (102).
[0029] The controller unit (106) is adapted to control the speed of the motor (104) by controlling the frequency of current supplied to the motor (104). The controller unit (106) is provided in communication with the motor (104) and the machine controller unit (not shown). The controller unit (106) is adapted to control acceleration and deceleration of the motor (104) during start and end of movement cycle of the automatic tool changer (10) respectively. For the purpose of this description and ease of understanding, the controller unit (106) is considered to be at least a variable frequency drive. However, it is also within the scope of this invention to provide any other type of controllers, without otherwise deterring the intended function of the controller unit (106) as can be deduced from the description and corresponding drawings. The controller unit (106) includes a display unit (106D) and a frequency setting knob (106K). The frequency setting knob (106K) is adapted to set frequency of current supplied to the motor (104). For example, the frequency setting knob (106K) is adapted to set desired frequency of current to the motor (104) to rotate the motor (104) at required speed in accordance to the movement cycle of the automatic tool changer (10). In another example, the frequency setting knob (106K) is adapted to be moved to at least one of a plurality of frequency positions therein to change the frequency of current supplied to the motor (104).
[0030] In an embodiment, the combination of the power transmission unit (102), the motor (104) and the controller unit (106) with consideration of parameters like torque, power ratio, braking and performance parameters provides the automatic tool changer system (100) with optimal or required braking torque and tool change time.
[0031] The presence detecting sensors (not shown) are provided on the output shaft (102P) of the power transmission unit (102) to detect the positions of the tool changer slide (12) of the automatic tool changer (10) based on the rotation of output shaft (102P), where the positions of the tool changer slide (12) are the tool change positions with respect to the tool magazine side and the machine spindle side. The plurality of presence detecting sensors (not shown) is adapted to be provided in communication with the machine (not shown). The presence detecting sensor(s) (not shown) is adapted to detect the presence of the automatic tool changer (10) at tool change positions and provides information to the machine (not shown). The machine in turn provides information to the controller unit (106) which de-energizes the brake unit (104B) to engage the brake unit (104B) with the shaft (104S) therein to provide braking torque to the automatic tool changer (10) to lock the automatic tool changer (10) at tool change positions against reaction force exerted during removal and insertion of tool(s) with respect to the tool magazine (not shown) and the machine spindle (not shown). For the purpose of this description and ease of understanding, each presence detecting sensor (not shown) is considered to be a proximity sensor. However, it is also within the scope of this invention to provide any other type of sensors for detecting the presence of the automatic tool changer (10) at tool change positions, without otherwise deterring the intended function of the presence detecting sensors as can be deduced from the description and corresponding drawings.
[0032] Fig. 5 depicts a flowchart indicating a method (200) of operating the automatic tool changer (10) in the machine, according to embodiments as disclosed herein. For the purpose of this description and ease of understanding, the method (200) is explained herein below with reference to operating the automatic tool changer (10) in a CNC machine such as horizontal machining centers (HMC). However, it is also within the scope of this invention to practice/implement the entire steps of the method (200) in a same manner or in a different manner or with omission of at least one step to the method (200) or with any addition of at least one step to the method (200) for operating the automatic tool changer (10) in vertical machining centers or any other type of CNC machines or any other metal working machines or automatic machining machines, without otherwise deterring the intended function of the method (200) as can be deduced from the description and corresponding drawings. The method (200) includes, energizing a brake unit (104B) of a motor (104) by switching on the current supply to the brake unit (104B) through a controller unit (106) to dis-engage the brake unit (104B) from a shaft (104S) of the motor (104) when the controller unit (106) receives information from the machine, step (202); energizing the motor (104) by controlling frequency of current to the motor (104) through the controller unit (106) therein to rotate the motor (104) at required speed, step (204); rotating movable member of the automatic tool changer (10) through a power transmission unit (102) and the motor (104) to move the automatic tool changer (10) from the tool magazine (not shown) towards the machine spindle (not shown) therein to transport a buffer tool (not shown) from the tool magazine (not shown) towards the machine spindle (not shown) when tool change is required by the machine, step (206); reducing the speed of the motor (104) by controlling the frequency of current to the motor (104) through the controller unit (106) at end of movement cycle of the automatic tool changer (10), step (208); providing braking torque to the automatic tool changer (10) through the power transmission unit (102) and a brake unit (104B) of the motor (104) therein to lock the automatic tool changer (10) at tool change position to enable the automatic tool changer (10) to remove a working tool from the machine spindle and insert the buffer tool to the machine spindle on engagement of the brake unit (104B) with the shaft (104S) of the motor (104) by de-energizing the brake unit (104B) through the controller unit (106), step (210).
[0033] The method step (210) of providing braking torque to the automatic tool changer (10) through the power transmission unit (102) and the brake unit (104B) of the motor (104) therein to lock the automatic tool changer (10) at tool change position to enable the automatic tool changer (10) to remove a working tool from the machine spindle and insert the buffer tool to the machine spindle on engagement of the brake unit (104B) with the shaft (104S) of the motor (104) by de-energizing the brake unit (104B) through the controller unit (106) comprises, increasing the braking torque of the motor (104) through the power transmission unit (102) and transmitting required braking torque to the automatic tool changer (10) by the power transmission unit (102) therein to restrict a movement of the automatic tool changer (10) at tool change position, and de-energizing the motor (104) by switching off current supply to the motor (104) through the controller unit (106) at tool change position when the controller unit (106) receives information from the machine.
[0034] The method (200) includes removing the buffer tool (not shown) from the tool magazine (not shown) through the automatic tool changer (10), step (201) prior to method step (202) of energizing the brake unit (104B) of the motor (104) by switching on current supply to the brake unit (104B) through the controller unit (106) to dis-engage the brake unit (104B) from the shaft (104S) of the motor (104).
[0035] The method (200) includes detecting the position of a tool changer slide (12) of the automatic tool changer (10) through corresponding presence detecting sensor at tool change position with respect to the machine spindle and providing the information to the machine which in turn provides information to the controller unit (106), step (209) prior to method step (210) of providing braking torque to the automatic tool changer (10) through the power transmission unit (102) and the brake unit (104B) of the motor (104) therein to lock the automatic tool changer (10) at tool change position to enable the automatic tool changer (10) to remove the working tool from the machine spindle and insert the buffer tool to the machine spindle on engagement of the brake unit (104B) with the shaft (104S) of the motor (104) by de-energizing the brake unit (104B) through the controller unit (106).
[0036] The method (200) comprises, energizing the brake unit (104B) of the motor (104) by switching on current supply to the brake unit (104B) through the controller unit (106) to dis-engage the brake unit (104B) from the shaft (104S) of the motor (104) and energizing the motor (104) by controlling frequency of current to the motor (104) through the controller unit (106) therein to rotate the motor (104) at required speed when the controller unit (106) receives information from the machine, step (212).
[0037] The method (200) comprises, rotating the movable member of the automatic tool changer (10) through the power transmission unit (102) and the motor (104) to move the automatic tool changer (10) from the machine spindle towards the tool magazine therein to transport the removed tool from the machine spindle towards the tool magazine, step (214).
[0038] The method (200) comprises, reducing the speed of the motor (104) by controlling the frequency of current to the motor (104) through the controller unit (106) at end of movement cycle of the automatic tool changer (10), step (216).
[0039] The method (200) comprises, detecting the position of the tool changer slide (12) of the automatic tool changer (10) through corresponding another presence detecting sensor at tool change position with respect to the tool magazine and providing the information to the machine which in turn provides information to the controller unit (106), step (218).
[0040] The method (200) comprises, providing braking torque to the power transmission unit (102) through the motor (104) and increasing the braking torque of the motor (104) through the power transmission unit (102) and transmitting required braking torque to the automatic tool changer (10) by the power transmission unit (102) therein to restrict the movement of the automatic tool changer (10) at tool change position to enable the automatic tool changer (10) to insert the removed tool to the tool magazine on engagement of the brake unit (104B) with the shaft (104S) of the motor (104) by de-energizing the brake unit (104B) through the controller unit (106), and de-energizing the motor (104) through the controller unit (106) when the controller unit (106) receives information from the machine, step (220).
[0041] The working of the automatic tool changer system (100) in conjunction with the method (200) for operating the automatic tool changer (10) is as follows. When there is a requirement to change the working tool in the machine spindle (not shown) due to the requirement of different machining operations performed by the machine (not shown). The machine provides signal to the controller unit (106) which energizes the brake unit (104B) of the motor (104) to dis-engage the brake unit (104B) from the shaft (104S) of the motor (104). Thereafter, the controller unit (106) energizes the motor (104) by controlling frequency of current to the motor (104) therein to rotate the motor (104) at required speed. The motor (104) in turn drives the automatic tool changer (10) through the power transmission unit (102) to move the automatic tool changer (10) from the tool magazine (not shown) to the machine spindle (not shown) therein to transport the buffer tool (not shown) removed by the automatic tool changer (10) from the tool magazine (not shown) to the machine spindle (not shown). Thereafter, the controller unit (106) controls the frequency of current to the motor (104) to reduce the speed of the motor (104) thereby reducing the speed of the automatic tool changer (10) when the automatic tool changer (104) reaches at the end of the movement cycle. Thereafter, the presence detecting sensor (not shown) detects the position of the tool changer slide (12) of the automatic tool changer (10) at tool change position with respect to the machine spindle and provides the information to the machine which in turn provides signal to the controller unit (106). On receiving the signal, the controller unit (106) de-energizes the brake unit (104B) to engage the brake unit (104B) with the shaft (104S) to restrict the rotation of the shaft (104S) thereby providing braking torque to the power transmission unit (102) which in turn increases the braking torque of the motor (104) and transmits required braking torque to the automatic tool changer (10) therein to restrict the movement of the automatic tool changer (10) at tool change position. Thereafter, the controller unit (106) de-energizes the motor (104) by switching off the current supply to the motor (104). Thereafter, the automatic tool changer (10) removes the working tool from the machine spindle (not shown) and inserts the buffer tool (not shown) to the machine spindle (not shown).
[0042] Now, the transportation of removed tool from the machine spindle (not shown) to the tool magazine (not shown) through the automatic tool changer (10) is as follows. The machine (not shown) provides signal to the controller unit (106) which energizes the brake unit (104B) of the motor (104) to dis-engage the brake unit (104B) from the shaft (104S) of the motor (104). Thereafter, the controller unit (106) energizes the motor (104) by controlling frequency of current to the motor (104) therein to rotate the motor (104) at required speed. The motor (104) in turn drives the automatic tool changer (10) through the power transmission unit (102) to move the automatic tool changer (10) from the machine spindle (not shown) to the tool magazine (not shown) therein to transport the removed tool (not shown) from the machine spindle (not shown) to the tool magazine (not shown). Thereafter, the controller unit (106) controls the frequency of current to the motor (104) to reduce the speed of the motor (104) thereby reducing the speed of the automatic tool changer (10) when the automatic tool changer (104) reaches at the end of the movement cycle. Thereafter, the presence detecting sensor (not shown) detects the position of the tool changer slide (12) of the automatic tool changer (10) at tool change position with respect to the tool magazine and provides the information to the machine which in turn provides signal to the controller unit (106). The controller unit (106) in turn de-energizes the brake unit (104B) to engage the brake unit (104B) with the shaft (104S) to restrict the rotation of the shaft (104S) thereby providing braking torque to the power transmission unit (102) which in turn increases the braking torque of the motor (104) and transmits required braking torque to the automatic tool changer (10) therein to restrict the movement of the automatic tool changer (10) at tool change position. Thereafter, the controller unit (106) de-energizes the motor (104) by switching off the current supply to the motor (104). Thereafter, the automatic tool changer (10) inserts the removed tool (not shown) to the tool magazine (not shown).
[0043] Therefore, an electro-mechanical automatic tool changer system (100) and a method (200) for operating an automatic tool changer (10) in a machine (no shown), which is reliable and retrofitted to an automatic tool changer and changes tool within standard tool change time and incurs less investment and maintenance costs is provided.
[0044] 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, 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 embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.
,CLAIMS:We claim,
1. An automatic tool changer system (100) for a machine, said system (100) comprising:
a power transmission unit (102) adapted to move a movable member of an automatic tool changer (10); and
a motor (104) comprising a shaft (104S), said shaft (104S) adapted to be rotatably coupled with said power transmission unit (102), and at least one brake unit (104B), said brake unit (104B) mounted onto said shaft (104S),
wherein
said motor (104) is adapted to move the automatic tool changer (10) between a tool magazine and a machine spindle; and
said brake unit (104B) is adapted to provide braking torque to the automatic tool changer (10) at tool change positions.

2. The automatic tool changer system (100) as claimed in claim 1, wherein said automatic tool changer system (100) comprises a controller unit (106) adapted to rotate said motor (104) at desired speed by regulating frequency of current supplied to said motor (104).

3. The automatic tool changer system (100) as claimed in claim 2, wherein said controller unit (106) is adapted to receive information from the machine and accordingly said controller unit (106) is adapted to energize said brake unit (104B) to dis-engage said brake unit (104B) from said shaft (104S);
said controller unit (106) is adapted to energize said motor (104) by controlling frequency current to said motor (104); and
said motor (104) drives the movable member of the automatic tool changer (10) through said power transmission unit (102) therein to move the automatic tool changer (10) between the tool magazine and the machine spindle when tool change is required by the machine.

4. The automatic tool changer system (100) as claimed in claim 2, wherein said controller unit (106) is adapted to receive information from the machine and accordingly said controller unit (106) is adapted to reduce the speed of said motor (104) at end of movement cycle of the automatic tool changer (10) by controlling the frequency of current provided to said motor (104);
said controller unit (106) is adapted to de-energize said brake unit (104B) therein to engage said brake unit (104B) with said shaft (104S) to provide braking torque to said power transmission unit (102); and
said power transmission unit (102) increases the braking torque received from said motor (104) and transmits braking torque to the automatic tool changer (10) therein to restrict a movement of the automatic tool changer (10) at tool change positions.

5. The automatic tool changer system (100) as claimed in claim 2, wherein said controller unit (106) is adapted to control acceleration and deceleration of said motor (104) during start and end of movement cycle of the automatic tool changer (10) respectively.

6. The automatic tool changer system (100) as claimed in claim 1, wherein said automatic tool changer system (100) comprises a first coupling flange (103) adapted to mount said power transmission unit (102) to the automatic tool changer (10),
wherein
one end of said first coupling flange (103) is fastened with a transmission housing (102H) of said power transmission unit (102) and another end of said first coupling flange (103) is fastened with the automatic tool changer (10).

7. The automatic tool changer system (100) as claimed in claim 1, wherein said automatic tool changer system (100) comprises a second coupling flange (105) adapted to mount said motor (104) to said power transmission unit (102).

8. The automatic tool changer system (100) as claimed in claim 1, wherein said power transmission unit (102) includes,
at least one reduction gear (102G);
an input shaft (102S) adapted to be rotatably connected with said reduction gear (102G), where said input shaft (102S) is coupled with said shaft (104S) of said motor (104); and
an output shaft (102P) adapted to be rotatably connected with said reduction gear (102G), where said output shaft (102P) is coupled with the movable member of the automatic tool changer (10).

9. The automatic tool changer system (100) as claimed in claim 8, wherein said input shaft (102S) is at least a worm shaft;
said reduction gear (102G) is at least a worm gear; and
said output shaft (102P) is at least a splined shaft.

10. The automatic tool changer system (100) as claimed in claim 1, wherein a gear ratio of said power transmission unit (102) is at least 20:1.

11. The automatic tool changer system (100) as claimed in claim 2, wherein said controller unit (106) includes,
a display unit (106D); and
a frequency setting knob (106K) adapted to set frequency of current supplied to said motor (104).

12. The automatic tool changer system (100) as claimed in claim 8, wherein said output shaft (102P) is co-axial to the movable member of the automatic tool changer (10);
said input shaft (102S) is transverse to said output shaft (102P) and the movable member of the automatic tool changer (10); and
said power transmission unit (102) is transverse to the movable member of the automatic tool changer (10).
13. The automatic tool changer system (100) as claimed in claim 2, wherein said controller unit (106) is at least a variable frequency drive;
said power transmission unit (102) is at least a reduction worm gearbox;
said motor (104) is at least an induction brake motor;
said brake unit (104B) is at least a disc brake; and
the movable member of the automatic tool changer (10) is a shaft.

14. The automatic tool changer system (100) as claimed in claim 4, wherein said system (100) comprises a plurality of sensors adapted to detect the tool change positions and accordingly provides the information to the machine which in turn provides information to said controller unit (106).

15. A method (200) of operating an automatic tool changer (10) in a machine, said method (200) comprising:
energizing a motor (104) by controlling frequency of current to the motor (104) through a controller unit (106) therein to rotate the motor (104);
moving the automatic tool changer (10), by the motor (104) and a power transmission unit (102), between a tool magazine and a machine spindle when tool change is required by the machine;
reducing the speed of the motor (104) by controlling frequency of current to the motor (104) through the controller unit (106) at end of movement cycle of the automatic tool changer (10); and
providing braking torque to the automatic tool changer (10) through the power transmission unit (102) and a brake unit (104B) therein to restrict a movement of the automatic tool changer (10) at tool change positions.

16. The method (200) as claimed in claim 15, wherein said providing braking torque to the automatic tool changer (10) through the power transmission unit (102) and the brake unit (104B) therein to restrict the movement of the automatic tool changer (10) at tool change positions comprises,
de-energizing the brake unit (104B) by switching off the current supply to the brake unit (104B) through the controller unit (106) to engage the brake unit (104B) with a shaft (104S) of the motor (104) thereby providing the braking torque to the power transmission unit (102);
increasing the braking torque of the motor (104) and transmitting braking torque to the automatic tool changer (10) by the power transmission unit (102) therein to restrict a movement of the automatic tool changer (10) at tool change position; and
de-energizing the motor (104) by switching off current supply to the motor (104) through the controller unit (106) at tool change positions when the controller unit (106) receives information from the machine.

17. The method (200) as claimed in claim 15, wherein said method (200) comprises, energizing the brake unit (104B) of the motor (104) by switching on current supply to the brake unit (104B) through the controller unit (106) to dis-engage the brake unit (104B) from the shaft (104S) of the motor (104) when the controller unit (106) receives information from the machine prior to said energizing the motor (104) by controlling frequency of current to the motor (104) through the controller unit (106) therein to rotate the motor (104).

18. The method (200) as claimed in claim 15, wherein said method (200) comprises,
detecting the tool change positions and providing the information to the machine through sensors; and
providing information to the controller unit (106) by the machine prior to said providing braking torque to the automatic tool changer (10) through the power transmission unit (102) and the brake unit (104B) therein to restrict the movement of the automatic tool changer (10) at tool change positions