Deep hole turning tool bar rolling support structure

Abstract

This utility model discloses a rolling support structure for deep hole turning tool holders, specifically relating to the fields of deep hole turning and boring machining. It includes a tool holder with a cutting head connected to one end. A ceramic bearing is fitted around the outside of the tool holder, with its inner ring adapted to the outer surface of the tool holder. A support sleeve is fitted around the ceramic bearing, and the outer wall of the support sleeve has multiple equidistant arc grooves. By setting up a support assembly composed of a ceramic bearing and a support sleeve, this utility model significantly reduces the torque generated by friction between the tool holder and the inner wall of the hole during deep hole turning and boring, thanks to the extremely low coefficient of friction of the ceramic bearing. Combined with the friction-reducing characteristics of rolling or sliding bearings, it significantly reduces energy loss and tool wear caused by friction. Simultaneously, it can also counteract the radial force generated during cutting, effectively suppressing tool holder deformation and vibration. This not only improves the rigidity of the tool holder but also ensures the stability of product dimensional accuracy and geometric tolerances.

Description

Technical Field

[0001] This utility model relates to the field of deep hole turning and boring technology, specifically to a rolling support structure for deep hole turning tool holders. Background Technology

[0002] Deep hole turning tool holders are important tools in the field of deep hole machining, playing a key role in deep hole turning and boring. They are usually made of high-strength alloy steel and undergo special heat treatment processes to ensure excellent strength and rigidity. The tool holders have an ingenious structural design, and their slender shape is specially designed to machine deep holes into the workpiece.

[0003] However, in deep hole machining, the slender tool holder, like a fragile cantilever suspended in the air under cutting forces, is prone to elastic deformation and vibration. This not only affects machining accuracy but also accelerates tool wear and shortens service life. Using a fixed support to enhance rigidity significantly increases the cutting torque, causing the torsional stress on the tool holder to accumulate continuously. Once the limit is exceeded, it is prone to breakage, resulting in tool damage and workpiece scrap. At the same time, the elastic deformation of the tool holder, the thermal expansion of the workpiece material caused by cutting heat, and the micro-vibrations of the machine tool system all contribute to deviations in the machined hole diameter, cylindricity deviations, and deterioration of surface roughness. These technical bottlenecks, formed by insufficient tool holder rigidity, excessive support torque, and multiple factors interfering with accuracy, make deep hole machining a recognized problem in the field of machining, seriously restricting the efficient production of high-precision deep hole parts. Therefore, a rolling support structure for deep hole turning tool holders is proposed. Utility Model Content

[0004] The purpose of this invention is to provide a rolling support structure for deep hole turning tool holders to address the aforementioned shortcomings in the technology.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a rolling support structure for deep hole turning tool holders, including a tool holder, one end of which is connected to a tool head. The tool holder includes a first rod body, a second rod body, and a third rod body connected in sequence. The first rod body has a conical structure, and the large-diameter end of the first rod body is coaxially connected to one end of the second rod body. The second rod body is an intermediate connecting section, which is cylindrical in shape and is used to transitionally connect the first rod body and the third rod body.

[0006] Preferably, a ceramic bearing is sleeved on the outside of the tool holder, the inner ring of the ceramic bearing is adapted to the outer circular surface of the tool holder, and a support sleeve is sleeved on the outside of the ceramic bearing.

[0007] Preferably, the ceramic bearing is sleeved on the outside of the third rod, and the end of the third rod away from the second rod is connected to the cutter head.

[0008] Through the above technical solution:

[0009] In deep hole turning and boring, the support assembly consisting of the ceramic bearing and the support sleeve significantly reduces the torque generated by friction between the tool holder and the inner wall of the hole due to the extremely low coefficient of friction of the ceramic bearing. Combined with the anti-friction characteristics of rolling or sliding bearings, it reduces energy loss and tool wear caused by friction. At the same time, it can also counteract the radial force generated during cutting, effectively suppressing the deformation and vibration of the tool holder. This not only improves the rigidity of the tool holder but also ensures the stability of product dimensional accuracy and geometric tolerances. In addition, the efficient distribution of radial force by the bearing can reduce the diameter of the tool holder, reduce its weight, and enhance dynamic response. The structure is simple and compact, easy to install and maintain, and can improve machining efficiency. It is suitable for precision machining of deep holes of a single size and can also be extended to various machining scenarios with extended tool holders.

[0010] Preferably, the outer wall of the support sleeve is provided with multiple arc grooves at equal intervals.

[0011] Specifically, in use, the arc groove plays a crucial chip removal role in the deep hole turning tool holder structure. By optimizing the chip removal path, the groove utilizes the centrifugal force generated by the tool rotation and the flushing effect of the cutting fluid to guide the chips to be quickly discharged out of the hole along the arc groove, effectively preventing chips from accumulating and clogging in the deep hole. At the same time, the smooth curved surface of the arc groove reduces the frictional resistance between the chips and the tool holder surface, reducing the risk of chips scratching the machined surface. Combined with the friction-reducing and rigidity-enhancing design of the support component, it can significantly improve the continuity and surface quality of deep hole machining.

[0012] Secondly, coating the outer circle of the support sleeve with wear-resistant coatings such as TiN and TiAlN (not shown in the figure) can reduce friction with the hole wall and extend service life. In addition, the support sleeve on the outer circle of the support sleeve can be designed as a spiral (not shown in the figure), which can enhance chip removal capability by utilizing the centrifugal force generated by the flow of cutting fluid and the rotation of the tool holder, and avoid chip accumulation.

[0013] In addition, during assembly, first install the ceramic bearing on the third rod of the tool holder, then put on the support sleeve, and finally install the tool head. After installation, the support sleeve should rotate flexibly without jamming. When in use, after adjusting the turning position of the tool holder, apply wear-resistant grease to the outer surface of the support sleeve to reduce the friction of the tool holder during feed.

[0014] Preferably, the tool holder is provided with a lubrication component for continuously delivering and supplying lubricating oil to the ceramic bearing through a "storage-adsorption-extrusion" cycle, thereby maintaining the lubrication state of the ceramic bearing.

[0015] Preferably, the lubrication assembly includes an oil reservoir formed on the inner wall of the tool holder, and a plurality of through holes are formed on the outer wall of the tool holder outside the oil reservoir, with a plug embedded at the lower end of each of the plurality of through holes.

[0016] Preferably, each of the multiple through holes has a retainer fixedly connected to its upper end. A sponge block is embedded inside the retainer. A connecting rope is connected through the retainer. One end of the connecting rope extends into the oil reservoir, and the other end of the connecting rope passes through and extends into the retainer to contact the sponge block.

[0017] Preferably, the outer wall of the plug is provided with a plurality of slots at equal intervals, and each of the plurality of slots is provided with a plug, which is fixedly connected to the inner wall of the through hole.

[0018] Preferably, the lubrication assembly further includes an inlet groove formed on the outer wall of the tool holder and located on one side of the oil reservoir.

[0019] Through the above technical solution:

[0020] Before use, lubricating oil is first injected into the oil storage tank through the inlet groove. This allows the cutter bar to store some lubricating oil, avoiding the tedious operation of frequent oiling. When lubricating the ceramic bearing, the connecting rope uses capillary action to draw lubricating oil from the oil storage tank. The lubricating oil rises along the tiny channels inside the rope and moves towards one end of the sponge block, where it is absorbed and stored. The vibration of the cutter bar causes the sponge block to be squeezed, forcing out the lubricating oil and applying it to the ceramic bearing. Through this "storage-absorption-squeezing" cycle mechanism, continuous lubrication of the ceramic bearing is achieved. This ensures long-term stable operation. Secondly, the operation is based on vibration-triggered on-demand oil supply, avoiding continuous dripping and contamination. Capillary action ensures a continuous supply of small amounts of oil, preventing the problems of excessive oil supply or instantaneous depletion that occur with traditional oil supply methods. This ensures that the lubricating oil accurately penetrates the bearing contact surface. In addition, its precise control capability adapts to the varying working conditions of the tool holder speed and load in deep hole machining, maintaining low friction and low wear operation of the bearing. Stable lubrication can be achieved without frequent maintenance, effectively reducing temperature rise, wear and vibration, extending bearing life, improving the rigidity and machining accuracy of the tool holder, and providing reliable support for deep hole machining.

[0021] Preferably, a plug is fitted into the inlet end of the liquid inlet tank, and a ring block is threadedly connected to the connecting end of the plug, and the ring block is fixedly connected to the inner wall of the liquid inlet tank.

[0022] Specifically, after oil injection, the plug is embedded in the inlet groove to block the lubricating oil and prevent it from overflowing during use. The plug and ring are threaded together to ensure a stable and reliable seal. This threaded connection not only facilitates the installation and removal of the plug for subsequent lubrication replenishment but also effectively prevents the plug from loosening and falling off under conditions of high-speed rotation and frequent vibration of the tool holder, avoiding contamination or lubrication failure caused by oil leakage. (The plug has multiple small vent holes, not shown in the figure; these vent holes employ a microporous capillary structure design with extremely small pore diameters.) (e.g., at the micrometer level) The inner wall of the pores utilizes the material's own properties to form a microscopic rough texture similar to capillaries. Air molecules can freely pass through the pores using the principle of gas diffusion, enabling air circulation. This balances the internal and external air pressure of the oil reservoir, preventing negative or positive pressure from forming in the oil reservoir due to temperature changes or lubricant consumption during the use of the tool holder, which could affect the normal operation of the lubrication components. At the same time, based on the surface tension of the lubricating oil and the tiny size of the vent holes, the lubricating oil will not leak through the vent holes, ensuring that while achieving the air pressure balance function, the effective storage amount of lubricating oil in the oil reservoir is maintained, guaranteeing a continuous lubrication supply to the ceramic bearing.

[0023] The technical effects and advantages provided by this utility model in the above technical solution are as follows:

[0024] 1. By setting up a support assembly consisting of ceramic bearings and a support sleeve, during deep hole turning and boring, the extremely low coefficient of friction of the ceramic bearings significantly reduces the torque generated by friction between the tool holder and the inner wall of the hole. Combined with the anti-friction characteristics of rolling or sliding bearings, this significantly reduces energy loss and tool wear caused by friction. At the same time, it can also counteract the radial force generated during cutting, effectively suppressing tool holder deformation and vibration. This not only improves the rigidity of the tool holder but also ensures the stability of product dimensional accuracy and geometric tolerances. Secondly, by efficiently distributing the radial force through the bearings, the diameter of the tool holder can be appropriately reduced, reducing the weight of the tool holder while enhancing its dynamic response performance. In addition, the structure is simple and compact, easy to install and maintain, and effectively improves machining efficiency while ensuring high-precision machining. It is especially suitable for precision turning and boring operations of single-size deep holes, providing a reliable solution to deep hole machining problems and can be extended to various extended tool holder machining scenarios.

[0025] 2. By incorporating a lubrication system, lubricating oil is injected into the reservoir through the inlet groove during use, allowing for oil storage within the tool holder. This avoids the tedious operation of frequent oiling. Its vibration-triggered dynamic oil supply mode releases lubricating oil as needed, effectively preventing cutting fluid contamination and waste caused by continuous dripping. Furthermore, the capillary action of the connecting rope ensures a continuous supply of lubricating oil in minute quantities. This prevents splashing contamination caused by excessive oil volume in traditional supply methods and avoids dry friction caused by instantaneous oil depletion due to vibration. It ensures that lubricating oil penetrates precisely to the bearing contact surface at a stable flow rate. This precise control capability allows it to adapt to the frequent changes in tool holder speed and cutting load during deep hole machining, maintaining a low-friction, low-wear operating state for the ceramic bearing. Consequently, it eliminates the need for frequent maintenance during long-term machining, effectively reducing bearing temperature rise, wear, and vibration caused by poor lubrication, extending bearing life, and simultaneously improving the overall rigidity and machining accuracy of the tool holder, providing reliable support for efficient and precise deep hole machining. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0027] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0028] Figure 2 This is a schematic diagram showing the connection between the ceramic bearing, support sleeve, and tool holder of this utility model;

[0029] Figure 3 This is a three-dimensional structural diagram of the support sleeve of this utility model;

[0030] Figure 4 This is a three-dimensional structural diagram of the tool holder of this utility model;

[0031] Figure 5 This is a schematic diagram of the prior art of this utility model;

[0032] Figure 6 This is a schematic diagram showing the connection between the lubrication component and the tool holder of this utility model;

[0033] Figure 7 This is an enlarged schematic diagram showing the connection between the connecting rope and the sponge block in this utility model;

[0034] Figure 8 This is a schematic diagram showing the disassembled parts of this utility model;

[0035] Figure 9 This is an enlarged schematic diagram showing the sponge block and connecting rope of this utility model disassembled;

[0036] Figure 10 This is an enlarged schematic diagram showing the disassembled plug and liquid inlet tank of this utility model.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Tool holder; 11. First rod body; 12. Second rod body; 13. Third rod body; 2. Tool head; 3. Ceramic bearing; 4. Support sleeve; 5. Arc groove; 6. Lubrication assembly; 61. Oil reservoir; 62. Through hole; 63. Plug; 64. Sleeve; 65. Sponge block; 66. Connecting rope; 67. Groove; 68. Insert; 611. Liquid inlet groove; 612. Plug; 613. Ring block. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0040] This utility model provides, for example Figure 1 , Figure 2 , Figure 4 and Figure 5 The deep hole turning tool holder rolling support structure shown includes:

[0041] The tool holder 1 has a tool head 2 connected to one end. The tool holder 1 includes a first rod body 11, a second rod body 12, and a third rod body 13 connected in sequence. The first rod body 11 has a conical structure, and the large-diameter end of the first rod body 11 is coaxially connected to one end of the second rod body 12. The second rod body 12 is an intermediate connecting section and is cylindrical in shape, used to transition between the first rod body 11 and the third rod body 13.

[0042] This utility model provides, for example Figures 1-3 The deep hole turning tool holder rolling support structure shown has a ceramic bearing 3 sleeved on the outside of the tool holder 1. The inner ring of the ceramic bearing 3 is adapted to the outer circular surface of the tool holder 1, and a support sleeve 4 is sleeved on the outside of the ceramic bearing 3.

[0043] The ceramic bearing 3 is sleeved on the outside of the third rod 13, and the end of the third rod 13 away from the second rod 12 is connected to the cutter head 2.

[0044] Through the above technical solution:

[0045] In deep hole turning and boring, the support assembly consisting of ceramic bearing 3 and support sleeve 4 significantly reduces the torque generated by friction between the tool holder 1 and the inner wall of the hole due to the extremely low coefficient of friction of ceramic bearing 3. Combined with the anti-friction characteristics of rolling or sliding bearings, it reduces energy loss and tool wear caused by friction. At the same time, it can also counteract the radial force generated by the cutting tool, effectively suppressing the deformation and vibration of the tool holder 1. This not only improves the rigidity of the tool holder 1, but also ensures the stability of product dimensional accuracy and geometric tolerances. In addition, the efficient distribution of radial force by the bearing can reduce the diameter of the tool holder 1, reduce its weight and enhance dynamic response. The structure is simple and compact, easy to install and maintain, and can improve machining efficiency. It is suitable for precision machining of deep holes of a single size, and can also be extended to various machining scenarios of extended tool holder 1.

[0046] Further, see Figure 3 As shown, the outer wall of the support sleeve 4 is provided with multiple arc grooves 5 at equal intervals.

[0047] Specifically, in use, the arc groove 5 plays a crucial chip removal function in the deep hole turning tool holder structure. This groove optimizes the chip removal path and utilizes the centrifugal force generated by the tool rotation and the flushing effect of the cutting fluid to guide the chips to be quickly discharged out of the hole along the arc groove, effectively preventing chips from accumulating and clogging in the deep hole. At the same time, the smooth curved surface of the arc groove 5 reduces the frictional resistance between the chips and the surface of the tool holder 1, reducing the risk of chips scratching the machined surface. Combined with the friction reduction and rigidity enhancement design of the support component, it can significantly improve the continuity and surface quality of deep hole machining.

[0048] Secondly, coating the outer circle of the support sleeve 4 with wear-resistant coatings such as TiN and TiAlN (not shown in the figure) can reduce friction with the hole wall and extend service life. In addition, the support sleeve 4 on the outer circle of the support sleeve 4 can be designed as a spiral (not shown in the figure), which can enhance the chip removal ability by utilizing the centrifugal force generated by the flow of cutting fluid and the rotation of the tool holder 1, and avoid chip accumulation.

[0049] In addition, during assembly, first install the ceramic bearing 3 on the third rod 13 of the tool holder 1, then put on the support sleeve 4, and finally install the tool head 2. After installation, the support sleeve 4 should rotate flexibly without jamming. When using, after adjusting the turning position of the tool holder 1, apply wear-resistant grease to the outer surface of the support sleeve 4 to reduce the friction of the tool holder 1 during feed.

[0050] This utility model provides, for example Figures 6-9 The deep hole turning tool holder rolling support structure shown has a lubrication component 6 on the tool holder 1, which continuously delivers and supplies lubricating oil to the ceramic bearing 3 through a "storage-adsorption-extrusion" cycle to maintain the lubrication state of the ceramic bearing 3.

[0051] The lubrication assembly 6 includes an oil reservoir 61 formed on the inner wall of the tool holder 1. Multiple through holes 62 are formed on the outer wall of the tool holder 1 and located outside the oil reservoir 61. A block 63 is embedded in the lower end of each of the multiple through holes 62.

[0052] Multiple through holes 62 are fixedly connected to the upper part of the inside of each sleeve 64. A sponge block 65 is embedded inside the sleeve 64. A connecting rope 66 is connected through the block 63. One end of the connecting rope 66 extends into the inside of the oil reservoir 61, and the other end of the connecting rope 66 passes through and extends into the inside of the sleeve 64 to contact the sponge block 65.

[0053] The outer wall of the block 63 is provided with multiple slots 67 at equal intervals, and each slot 67 is provided with a block 68, which is fixedly connected to the inner wall of the through hole 62.

[0054] The lubrication assembly 6 also includes an inlet groove 611 that is formed on the outer wall of the tool holder 1 and located on one side of the oil reservoir 61.

[0055] Through the above technical solution:

[0056] Before use, lubricating oil is first injected into the oil storage tank 61 through the inlet tank 611. This allows the cutter bar 1 to store some lubricating oil, avoiding the tedious operation of frequent oiling. When lubricating the ceramic bearing 3, the connecting rope 66 uses capillary action to draw lubricating oil from the oil storage tank 61. The lubricating oil rises along the tiny channels inside the rope and moves towards one end of the sponge block 65, where it is absorbed and stored. The vibration of the cutter bar 1 causes the sponge block 65 to be squeezed, squeezing out the lubricating oil and applying it to the ceramic bearing 3. Through the "storage-absorption-squeezing" cycle mechanism, continuous lubrication of the ceramic bearing 3 is achieved. To ensure its long-term stable operation, the operation is based on vibration-triggered on-demand oil supply, avoiding continuous dripping and contamination. Capillary action ensures a continuous supply of small amounts of oil, preventing the problems of excessive oil supply or instantaneous depletion that occur with traditional oil supply methods. This ensures that the lubricating oil accurately penetrates the bearing contact surface. In addition, its precise control capability adapts to the working conditions of varying speed and load of the tool holder 1 in deep hole machining, maintaining low friction and low wear operation of the bearing. Stable lubrication can be achieved without frequent maintenance, effectively reducing temperature rise, wear and vibration, extending bearing life, improving the rigidity and machining accuracy of the tool holder 1, and providing reliable support for deep hole machining.

[0057] Further, see Figure 8 and Figure 10 As shown, a plug 612 is fitted into the inlet end of the liquid inlet tank 611, and a ring block 613 is threadedly connected to the connecting end of the plug 612. The ring block 613 is fixedly connected to the inner wall of the liquid inlet tank 611.

[0058] Specifically, after oil injection, the plug 612 is embedded in the inlet groove 611 to block the lubricating oil and prevent it from overflowing during use. The plug 612 and the ring block 613 are threaded together to ensure the stability and reliability of the seal. The threaded connection not only facilitates the installation and removal of the plug 612 for subsequent lubricating oil replenishment, but also effectively prevents the plug 612 from loosening and falling off under the conditions of high-speed rotation and frequent vibration of the tool holder 1, avoiding contamination or lubrication failure caused by lubricating oil leakage. (The plug 612 has multiple small vent holes, not shown in the figure. These vent holes adopt a microporous capillary structure design.) The diameter is extremely small (e.g., micrometer level), and the inner wall of the channel utilizes the material's own properties to form a microscopic rough texture similar to a capillary. Air molecules can freely pass through the channel by means of gas diffusion, enabling air circulation. This is used to balance the internal and external air pressure of the oil reservoir 61, preventing negative or positive pressure from forming in the oil reservoir 61 due to temperature changes or lubricant consumption during the use of the tool holder 1, which would affect the normal operation of the lubrication component 6. At the same time, based on the surface tension of the lubricating oil and the tiny size of the vent hole, the lubricating oil will not leak through the vent hole, ensuring that while achieving the air pressure balance function, the effective storage amount of lubricating oil in the oil reservoir 61 is maintained, ensuring a continuous lubrication supply to the ceramic bearing 3.

[0059] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A rolling support structure for deep hole turning tool holders, characterized in that, include: A tool holder (1) is connected to a tool head (2) at one end, and a ceramic bearing (3) is sleeved on the outside of the tool holder (1). The inner ring of the ceramic bearing (3) is adapted to the outer circular surface of the tool holder (1), and a support sleeve (4) is sleeved on the outside of the ceramic bearing (3). Multiple arc grooves (5) are equidistantly opened on the outer wall of the support sleeve (4). The tool holder (1) is provided with a lubrication component (6) for continuously supplying lubricating oil to the ceramic bearing (3) through a "storage-adsorption-extrusion" cycle, thereby maintaining the lubrication state of the ceramic bearing (3).

2. The deep hole turning tool holder rolling support structure according to claim 1, characterized in that: The tool holder (1) includes a first rod (11), a second rod (12) and a third rod (13) connected in sequence. The first rod (11) has a tapered structure, and the large-diameter end of the first rod (11) is coaxially connected to one end of the second rod (12). The second rod (12) is an intermediate connecting section, which is cylindrical in shape and is used to transitionally connect the first rod (11) and the third rod (13).

3. The rolling support structure for deep hole turning tool holders according to claim 2, characterized in that: The ceramic bearing (3) is sleeved on the outside of the third rod (13), and the end of the third rod (13) away from the second rod (12) is connected to the cutter head (2).

4. The rolling support structure for deep hole turning tool holders according to claim 1, characterized in that: The lubrication assembly (6) includes an oil reservoir (61) formed on the inner wall of the tool holder (1). The outer wall of the tool holder (1) and the outer side of the oil reservoir (61) are provided with a plurality of through holes (62). The lower end of the interior of each of the plurality of through holes (62) is fitted with a plug (63).

5. The deep hole turning tool holder rolling support structure according to claim 4, characterized in that: A sleeve (64) is fixedly connected to the upper part of the interior of each of the multiple through holes (62). A sponge block (65) is embedded inside the sleeve (64). A connecting rope (66) is connected through the block (63). One end of the connecting rope (66) extends into the interior of the oil reservoir (61), and the other end of the connecting rope (66) passes through and extends into the interior of the sleeve (64) to contact the sponge block (65).

6. The rolling support structure for deep hole turning tool holders according to claim 5, characterized in that: The outer wall of the block (63) is provided with a plurality of slots (67) at equal intervals, and each slot (67) is provided with an insert (68), which is fixedly connected to the inner wall of the through hole (62).

7. The rolling support structure for deep hole turning tool holders according to claim 6, characterized in that: The lubrication assembly (6) also includes an inlet groove (611) provided on the outer wall of the tool holder (1) and on one side of the oil reservoir (61). A plug (612) is embedded at the inlet end of the inlet groove (611). A ring block (613) is externally threaded to the connecting end of the plug block (612). The ring block (613) is fixedly connected to the inner wall of the inlet groove (611).

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