Patent Publication Number: US-2020276681-A1

Title: Tool Holder Having An Arrangement For Delivering Coolant And Transmitting Electric Power

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to relates to tool holders and more particularly to a tool holder having an arrangement for delivering coolant and transmitting electric power. 
     2. Description of Related Art 
     Conventional high precision machining including drilling, milling, boring, cutting and polishing often uses computer numerical control (CNC) machine as an auxiliary device in cooperation with tools such as drills, cutters, or the like. The tools are shaped as an elongated handle. A tool holder may secure the tool to the spindle of the CNC machine. The spindle rotates in high speed to rotate the tool fastened by the tool holder for machining a workpiece. 
     Typically, coolant is used to cool and lubricate a workpiece being machined so as to obtain the following benefits; keeping the workpiece at a stable temperature. Very warm is acceptable, but extremely hot or alternating hot-and-cold are avoided. maximizing the life of the cutting tip by lubricating the working edge. Ensuring safety for the people handling it and for the environment upon disposal. Preventing rust on machine parts and cutters. Conventionally, the coolant is delivered through a chuck or the like in a machining process. 
     It is known that the tool holder may vibrate strongly in machining and it may interfere with the machining, resulting in a poor quality of the finished workpiece. Further, components may collide one another resulting in undesired vibration which may interfere with the high frequency vibration. An in turn, it may adversely affect precision of the workpiece, and damage both the machine and the tool holder. 
     In a cutting process, any vibration between the tool holder and the workpiece may undesirably affect cutting and unsmooth surface and unacceptable quality of the workpiece. To the worse, the vibration may damage the tool holder and/or the tool. It is found that the longer of the tool holder the more serious of the vibration. Elongated tool holders are disclosed by U.S. Pat. Nos. 1,502,528, 2,716,030 and 8,821,084. For high length to diameter ratio, the precision of the workpiece may be very low or even be impossible of being machined due to rigidity of the material of the tool holder. These are problems encountered by the conventional machines. It may cause strong interference to undesirably vibrate the tool holder. The cutting effect is adversely affected. Also, smoothness and quality of the workpiece are low. To the worse, the machines are damaged. 
     Thus, the need for improvement still exists. 
     SUMMARY OF THE INVENTION 
     It is therefore one object of the invention to provide a tool holder having an arrangement for delivering coolant and transmitting electric power wherein the actuator is disposed in the tool mounting member so that the path for transmitting electric power can be greatly decreased. Further, undesired vibration to the tool holder by the high frequency vibration may be eliminated. Furthermore, the inadequate rigidity of the material of the conventional tool holder having a high L/D ratio is improved. In addition, smoothness and quality of the workpiece are improved. In addition, coolant delivery through the first channel and wire passing through the second channel for transmitting electric power are made independently. Additionally, the provision of the sleeves may lengthen the tool holder if such need arises. 
     It is another object of the invention to provide a tool holder having an arrangement for delivering coolant and transmitting electric power wherein the inadequate rigidity of the material of the conventional tool holder having a high L/D ratio is improved, and the high L/D ratio is significantly decreased. As shown in  FIG. 1 , the length to diameter ratio before the installation of the actuator labeled L 1 /D is decreased to L/D after the installation of the actuator. Further, the provision of at least one sleeve can lengthen the tool holder while the L/D is fixed irrespective of the value of L 1 . 
     It is a further object of the invention to provide a tool holder having an arrangement for delivering coolant and transmitting electric power wherein the length of the tool holder can be changed by providing at least one sleeve interconnecting a connector and a tool mounting member. 
     For achieving above an other objects of the invention, there is provided a tool holder used in a machine which supplies power via a spindle and deliveries coolant, comprising a connector received in the spindle; a conductive ring disposed on the connector and electrically connected to the spindle so as that power is configured to supply to the tool holder; a tool mounting member including an axial hole for fastening a portion of a tool; an actuator disposed in the tool mounting member and electrically connected to the conductive ring so that power supplied to the actuator is configured to transmit to the tool via the axial hole; an axial passageway disposed through both the connector and the tool mounting member; and a waterproof dividing member for dividing the axial passageway into a first channel for delivering coolant and a second channel for passing a wire; wherein the first channel is spaced from the second channel so that electric power transmission and coolant delivery are made independently. 
     Preferably, the waterproof dividing member includes a plurality of dividing elements complimentarily secured together. 
     Preferably, the connector includes an axial tunnel for conveying coolant from the spindle to the first channel. 
     Preferably, the actuator is an oscillator for producing ultrasonic vibration, an electric device, or a pneumatic device. 
     Preferably, the tool mounting member further comprises a flexible chuck having the axial hole disposed therein, the flexible chuck including a plurality of lengthwise parallel slits each having an open end, and a plurality of latches each disposed between two adjacent ones of the slits; and a fastener disposed on an end of the flexible chuck so that a force exerted upon the flexible chuck is configured to flexibly deform the latches to fasten the tool in the flexible chuck. 
     Preferably, the tool mounting member further comprises an axial tunnel member for delivering coolant from the first channel to the flexible chuck. 
     Preferably, there is further provided at least one sleeve interconnecting the connector and the tool mounting member. 
     Preferably, each sleeve includes a projection at one end and a receptacle at the other end so that the at least one sleeve is configured to complimentarily attach to both the connector and the tool mounting member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, as well as its many advantages, may be further understood by the following detailed description and drawings in which: 
         FIG. 1  is a longitudinal sectional view of a tool holder having an arrangement for delivering coolant and transmitting electric power according to the invention; and 
         FIG. 2  is a detailed view of the area in right side of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 and 2 , a tool holder having an arrangement for delivering coolant and transmitting electric power according to the invention is used in a machine which supplies power via a spindle (not shown). The tool holder comprises a connector  10  received in the spindle, a conductive ring  11  disposed on the connector  10  and electrically connected to the spindle so that power may be supplied to the tool holder; a substantially cylindrical tool mounting member  20  including an axial hole  21  for fastening a portion of a tool (e.g., tool handle but not shown); and an actuator  30  disposed in the tool mounting member  20  and electrically connected to the conductive ring  11  so that power may be supplied to the actuator  30 . The produced vibration of high frequency is transmitted to the tool via the axial hole  21 . 
     The tool holder further comprises an axial passageway  50  through both the connector  10  and the tool mounting member  20 , and a waterproof dividing member  51  for dividing the axial passageway  50  into a first channel  52  for delivering coolant and a second channel  53  for passing a wire. The first channel  52  is spaced from the second channel  53  so that electric power transmission and coolant delivery can be made independently. As a result, the actuator  30  can greatly decrease the path for transmitting electric power. 
     The actuator  30  is implemented as an oscillator for producing ultrasonic vibration, an electric device, or a pneumatic device. When the actuator  30  is a pneumatic device, the conductive ring  11  can be replaced with a pneumatic member and the second channel  53  can be replaced with a gas channel by one skilled in the art. 
     The connector  10  has a stepped-diameter outer surface  15  which is configured to receive in the spindle of a machine. Thus, the tool holder may be aligned with the spindle to be secured together. The connector  10  includes an axial tunnel  16  for conveying coolant from the spindle to the first channel  52 . 
     The substantially cylindrical tool mounting member  20  includes a flexible chuck  22  having the axial hole  21  formed therein, a plurality of lengthwise parallel slits  23  each having an opening at one end, a plurality of latches  24  each disposed between two adjacent ones of the slits  23 , and a fastener  25  disposed on one end of the flexible chuck  22  to exert a force to flexibly deform the latches  24  so that a tool (not shown) disposed in the flexible chuck  22  can be fastened. The fastening of the tool using the flexible chuck  22  is one of a plurality of fastening methods. Those skilled in the art may be aware of other fastening methods. 
     The waterproof dividing member  51  includes a plurality of dividing elements  54  complimentarily secured together. Further, two ends of the waterproof dividing member  51  are secured to inside of the connector  10  and inside of the tool mounting member  20  respectively. Thus, the desired positioning and waterproof characteristics of the invention are obtained. O-rings, gaskets, washers or the like may be used to fill the space between two mating surfaces of the two adjacent dividing elements  54  (or two mating surfaces of the dividing element  54  and an adjacent member) to prevent water from the first channel  52  and/or the second channel  53  entering the joined objects while under compression. Likewise, in the implementation of conveying gas, the sealing members can prevent gas including air from entering the joined objects while under compression. This is well known to those skilled in the art. 
     The dividing element  54  includes the axial first channel  52  for delivering coolant having a circular section. The second channel  53  for passing a wire hole having a circular section is formed between the dividing element  54  and an inner surface of the axial passageway  50 . 
     The tool mounting member  20  further comprises an axial tunnel member  27  for delivering coolant from the first channel  52  to the flexible chuck  22 . 
     A wire  13  has one end electrically connected to the actuator  30  and the other end electrically connected to the conductive ring  11  by passing through the second channel  53 . A non-contact conductive connection (e.g., electromagnetic induction) can be implemented between the conductive ring  11  and the spindle of the machine. Alternatively, a two-terminal conductive contact between the conductive ring  11  and the spindle of the machine can be implemented. As a result, power is supplied to the conductive ring  11 . Details thereof are omitted herein for the sake of brevity. 
     In another preferred embodiment of the invention, there is further provided a plurality of (e.g., two) sleeves  40  disposed between the connector  10  and the tool mounting member  20 . Each sleeve  40  includes a projection  41  at one end and a receptacle  42  at the other end so that the projection  41  of one sleeve  40  can be complimentarily attached to the receptacle  42  of the other sleeve  40 . A protrusion  14  is provided at one end of the connector  10  for complimentarily attaching to the receptacle  42  of one sleeve  40 , and a cavity  26  is provided at the other end of the tool mounting member  20  for complimentarily attaching to the projection  41  of the other sleeve  40 . As a result, the connector  10 , the sleeves  40  and the tool mounting member  20  are secured together. The number of the sleeves  40  can be increased or decreased depending applications. Thus, the length of the tool holder can be adjusted. 
     It is envisaged by the tool holder having an arrangement for delivering coolant and transmitting electric power of the invention that the actuator is disposed in the tool mounting member so that the path for transmitting electric power can be greatly decreased. Further, undesired vibration to the tool holder by the high frequency vibration may be eliminated. Furthermore, the inadequate rigidity of the material of the conventional tool holder having a high L/D ratio is improved. In addition, smoothness and quality of the workpiece are improved. In addition, coolant delivery through the first channel and wire passing through the second channel for transmitting electric power are made independently. Additionally, the provision of the sleeves may lengthen the tool holder if such need arises. 
     Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.