Combined clamp applied to gearbox gear machining

Abstract

The invention discloses a combined clamp applied to gearbox gear machining. The combined clamp comprises a supporting base, a clamping structure arranged on the supporting base and used for fixing a gear and a positioning structure used for driving the clamping structure to move. A lifting structure is arranged on the upper surface of the base; a positioning structure is arranged on the upper surface of the lifting structure; the positioning structure comprises a fixed column fixed to the top of the lifting structure, the top of the fixed column is rotationally connected with a rotating disc, the upper surface of the rotating disc is fixedly connected with a supporting column, the top of the supporting column is fixedly connected with a traction plate, the traction plate is rotationally connected with a plurality of traction rods at equal intervals in the circumferential direction, and each traction rod is rotationally connected with a movable block. The positioning structure and the lifting structure are arranged and matched with the clamping structure, clamping of the inner ring and the outer ring of the gear can be completed only through one set of technical scheme, the structure is simplified, and operation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of gear processing, and in particular to a combined fixture used for gear processing of a gearbox. Background Art

[0002] In the motorcycle gear processing, the fixture plays a vital role, mainly in ensuring processing accuracy, improving production efficiency, expanding the process range of machine tools, and ensuring processing safety. In order to meet various requirements, many combined fixtures are designed in the prior art, but the structure of these combined fixtures is relatively complex. For example, the Chinese invention patent with the document number CN118848129A, named a combined fixture for automobile gearbox gear processing, and the Chinese invention patent with the document number CN112958854B, named a combined fixture for automobile gearbox gear processing, although these combined fixtures can realize gear positioning, but when clamping the inner ring and the outer ring of the gear, two sets of technical solutions are required to achieve it, so the structure is too complicated and the operation is inconvenient. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a combined fixture for gearbox gear processing. By setting a positioning structure and a lifting structure and cooperating with a clamping structure, only one set of technical solutions is needed to complete the clamping of the inner and outer rings of the gear, thereby simplifying the structure and facilitating operation.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a combined fixture used for gearbox gear processing, comprising a support seat, a clamping structure arranged on the support seat for fixing the gear, and a positioning structure for driving the clamping structure to move;

[0005] The support base includes a base, a workbench located above the base, and a first lifting column connected to the base and the workbench;

[0006] A lifting structure is arranged on the upper surface of the base, and a positioning structure is arranged on the upper surface of the lifting structure; the positioning structure comprises a fixed column fixed on the top of the lifting structure, a turntable is rotatably connected to the top of the fixed column, a pillar is fixedly connected to the upper surface of the turntable, a traction plate is fixedly connected to the top of the pillar, the traction plate is rotatably connected to a plurality of traction rods equidistantly along the circumferential direction, and each traction rod is rotatably connected to a movable block;

[0007] The workbench is provided with a plurality of clamping channels at equal intervals along the circumferential direction, and the movable blocks are located in the clamping channels and are slidably connected with the clamping channels.

[0008] Furthermore, a slot structure, a top structure, a sleeve structure, or a flange structure is provided at the bottom of the base.

[0009] Furthermore, the lifting structure includes a second lifting column fixed on the upper surface of the base, and an adjustment platform fixed on the top of the second lifting column.

[0010] Furthermore, the clamping structure includes a connecting screw threadedly connected to the movable block, and a main board threadedly connected to the connecting screw.

[0011] Furthermore, an extension plate is detachably connected to the side of the main board; there are a plurality of extension plates, and the plurality of extension plates are detachably connected in sequence.

[0012] Furthermore, the main board and the extension board are both arc-shaped.

[0013] Furthermore, a braking structure for fixing the turntable is arranged on the adjusting platform.

[0014] Furthermore, the braking structure includes two first brake rods and second brake rods symmetrically arranged on the outside of the turntable and fitted therewith; the first end of the first brake rod is rotatably connected to the first fixed shaft, and the first fixed shaft is fixedly connected to the turntable; the second end of the second brake rod is rotatably connected to the second fixed shaft, and the second fixed shaft is fixedly connected to the turntable; a manual rod is arranged on the outside of the second brake rod, the first end of the manual rod is rotatably connected to the second transmission rod, and the second transmission rod is rotatably connected to the first end of the second brake rod; the second end of the manual rod is rotatably connected to the first transmission rod, and the first transmission rod is rotatably connected to the second end of the first brake rod; the manual rod is rotatably connected to the third fixed shaft, and the third fixed shaft is fixedly connected to the adjustment platform.

[0015] Furthermore, a spring is arranged between the first end of the second brake rod and the first fixed shaft; when the manual rod is not subjected to external force, the spring is in a stretched state, and the turntable is squeezed and arranged between the first brake rod and the second brake rod; the second brake rod and the first fixed shaft are both connected to the spring through a connecting structure; the connecting structure includes a fixed block fixedly connected to the second brake rod or the first fixed shaft; the fixed block is provided with a spherical groove, and a movable ball is arranged in the spherical groove, and the diameter of the movable ball is smaller than the diameter of the spherical groove, and the two ends of the spring are respectively fixedly connected to the movable balls corresponding to the second brake rod and the first fixed shaft.

[0016] Furthermore, a rotating handle is fixedly installed on the turntable; baffles are vertically arranged on the lower surface of the workbench at both sides of the clamping channel; and a plurality of annular and concentric sink grooves are opened on the upper surface of the workbench.

[0017] The beneficial effects of the present invention are: 1. By setting a positioning structure and a lifting structure in cooperation with the clamping structure, when the clamping position needs to be changed from the inner ring of the gear to the outer ring, it is only necessary to lower the positioning structure, and then adjust the position of the clamping structure through the positioning structure, and then lift the clamping structure to position the gear. Only one set of technical solutions is needed to complete the clamping of the inner ring and the outer ring of the gear, which simplifies the structure, facilitates operation, and reduces costs.

[0018] 2. Because there are many types and sizes of gears, and the clamping forces that gears in different positions and with different functions can withstand are also very different, it may be troublesome to use a motor to drive and brake the positioning structure. Different gears require a separate adjustment control system, so a braking structure is set up, and the staff can easily and instantly control the clamping force according to the force that different gears can withstand. The operation is convenient, and the clamping force can be adjusted at any time according to the processing conditions; by setting up the clamping structure, it can be adjusted according to the size of the inner and outer rings of the gear to ensure a larger contact range, improve the clamping effect, and avoid excessive clamping force due to a small clamping range, thereby causing gear wear; there are multiple curvatures of the main board and extension plate, and different main boards and extension plates can be selected according to the size of the gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure;

[0020] Figure 2 It is a schematic diagram of the structure from a top view;

[0021] Figure 3 It is a schematic diagram of the clamping channel;

[0022] Figure 4 It is a schematic diagram of the local structure;

[0023] Figure 5 It is a schematic diagram of the structure of the disassembled state of the clamping plate;

[0024] Figure 6 is a schematic diagram of the brake structure;

[0025] Figure 7 is a schematic diagram of the connection structure;

[0026] Figure 8 It is a schematic diagram of the top structure of the fixed mounting seat;

[0027] Fig. 9 A schematic diagram of the shaft sleeve structure for fixing the mounting seat;

[0028] Fig.10 Schematic diagram of the flange structure of the fixed mounting base.

[0029] In the figure: 1, base; 2, slot structure; 201, top structure; 202, sleeve structure; 203, flange structure; 3, bottom support block; 4, first lifting column; 5, workbench; 6, top support block; 7, gear; 8, clamping channel; 801, baffle; 802, sink; 9, second lifting column; 10, adjustment platform; 11, positioning structure; 1101, fixed column; 1102, turntable; 1103, pillar; 1104, traction plate; 1105, traction rod; 1106, movable block; 12, clamping structure; 1201, Connecting screw; 1202, main board; 1203, screw hole; 1204, main board slot; 1205, extension plate; 1206, clamping strip; 1207, extension plate slot; 13, braking structure; 1301, first braking rod; 1302, second braking rod; 1303, first fixed axis; 1304, second fixed axis; 1305, manual rod; 1306, first transmission rod; 1307, third fixed axis; 1308, second transmission rod; 14, fixed block; 15, spherical groove; 16, movable ball; 17, rotating handle; 18, spring. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] The directional terms mentioned in the present invention, such as "up", "down", "front", "back", "left", "right", "inside", "outside", "side", "top" and "bottom", are only for reference to the orientation of the drawings. The directional terms used are used to illustrate and understand the present invention, but not to limit the present invention.

[0032] Embodiment 1:

[0033] like Figure 1-Figure 10 As shown, a combined fixture used for gearbox gear processing includes a support seat, a gear 7 placed on the support seat, a clamping structure 12 arranged on the support seat for fixing the gear 7, and a positioning structure 11 for driving the clamping structure 12 to move;

[0034] The support base includes a base 1, a workbench 5 located above the base 1, and a first lifting column 4 arranged vertically and connected to the base 1 and the workbench 5; the first lifting column 4 can be a cylinder or a hydraulic cylinder or an electric push rod, etc., or other structures capable of lifting and lowering can be used; a plurality of bottom support blocks 3 are symmetrically arranged on the outside of the base 1, and a top support block 6 corresponding in position and number to the bottom support block 3 is arranged on the outside of the workbench 5. There are a plurality of first lifting columns 4, the bottom of which is fixed on the bottom support block 3, and the top is fixedly connected to the top support block 6;

[0035] A lifting structure is provided on the upper surface of the base 1, and a positioning structure 11 is provided on the upper surface of the lifting structure; the positioning structure 11 comprises a fixed column 1101 fixed on the top of the lifting structure, a turntable 1102 is rotatably connected to the top of the fixed column 1101, a vertically arranged pillar 1103 is fixedly connected to the upper surface of the turntable 1102, a traction plate 1104 is fixedly connected to the top of the pillar 1103, the traction plate 1104 is rotatably connected to a plurality of traction rods 1105 equidistantly along the circumferential direction, and each traction rod 1105 is rotatably connected to a movable block 1106;

[0036] The workbench 5 is provided with a number of vertically penetrating clamping channels 8 equidistantly arranged along the circumference. The center of the workbench 5 and the center of the traction plate 1104 are located on the same vertical line. The movable block 1106 is located in the clamping channel 8 and is slidably connected thereto. All the clamping channels 8 are connected at the center of the workbench 5. The gear 7 is located at the center. The workbench 5 and the base 1 are both circular, so the center is the center of the circle.

[0037] A slot structure 2 or a top structure 201 or a sleeve structure 202 or a flange structure 203 connected to the gear processing table is provided at the bottom of the base 1; the slot structure 2 is mostly a combination of a trapezoidal slot and a trapezoidal block, and other types of slots can also be used for fixing; the top structure 201 includes a conical slot opened at the bottom of the base 1 and a conical column installed on the gear processing table; the sleeve structure 202 includes a shaft installed at the bottom of the base 1 and a sleeve installed on the gear processing table; the flange structure 203 includes flanges installed on the base 1 and the gear processing table that are compatible with each other.

[0038] The lifting structure includes a second lifting column 9 fixed on the upper surface of the base 1 and an adjustment platform 10 fixed on the top of the second lifting column 9 ; the second lifting column 9 is the same as the first lifting column 4 ; the fixed column 1101 is fixed on the upper surface of the adjustment platform 10 .

[0039] The clamping structure 12 includes a connecting screw 1201 which is vertically arranged and threadedly connected to the movable block 1106, and a main board 1202 which is threadedly connected to the connecting screw 1201 and is used to clamp the gear 7; the main board 1202 is vertically provided with a screw hole 1203, and the main board 1202 is connected to the connecting screw 1201 through the screw hole 1203 and the thread cooperation with the connecting screw 1201 to achieve its connection with the connecting screw 1201.

[0040] An extension plate 1205 is detachably connected to the side of the main board 1202; a main board slot 1204 is provided on the side of the main board 1202, and a clamping strip 1206 adapted to the main board slot 1204 is provided at a position on the side of the extension plate 1205 corresponding to the main board slot 1204, and the connection between the main board 1202 and the extension plate 1205 is achieved by plugging the clamping strip 1206 into the main board slot 1204; there are several extension plates 1205, and the several extension plates 1205 are detachably connected in sequence; a clamping strip 1206 is provided on one side of the extension plate 1205, and an extension plate slot 1207 is provided on the other side, and the extension plate slot 1207 is clamped with the clamping strips 1206 of other extension plates 1205 to achieve the connection between the two extension plates 1205.

[0041] The main board 1202 and the extension board 1205 are both arc-shaped, and the arc shape facilitates close contact with the inner ring or outer ring of the gear 7. The main board 1202 and the extension board 1205 have various curvatures and can be replaced according to the size of the gear 7.

[0042] A rotating handle 17 is fixedly installed on the upper surface of the turntable 1102 to facilitate the rotation of the turntable 1102; baffles 801 are vertically arranged on the lower surface of the workbench 5 at both sides of the clamping channel 8 to prevent the clamping structure 12 from detaching from the clamping channel 8 when it descends; a plurality of annular and concentric grooves 802 are provided on the upper surface of the workbench 5, and the centers of all the grooves 802 are located at the same point as the centers of the workbench 5 and the gear 7; the provision of the grooves 802 can further prevent the gear 7 from sliding during the processing process.

[0043] By setting a positioning structure and a lifting structure in coordination with the clamping structure, when the clamping position needs to be changed from the inner ring of the gear to the outer ring, it is only necessary to lower the positioning structure, and then adjust the position of the clamping structure through the positioning structure, and then lift the clamping structure to position the gear. Only one set of technical solutions is needed to complete the clamping of the inner and outer rings of the gear, which simplifies the structure, facilitates operation, and reduces costs.

[0044] Embodiment 2:

[0045] What is different from the first embodiment is that a brake structure 13 for fixing the turntable 1102 is provided on the adjustment platform 10. The brake structure 13 is provided to control the rotation and stop of the turntable 1102, and manual direct adjustment is convenient and quick.

[0046] like Figure 6As shown, the brake structure 13 includes two first brake rods 1301 and second brake rods 1302 symmetrically arranged on the outer side of the rotating disk 1102 and attached thereto; the first brake rod 1301 and the second brake rod 1302 each have two ends, which are parallel to each other; the first end of the first brake rod 1301 corresponds to the first end of the second brake rod 1302, and the second ends of the two brake rods correspond to each other; the first end of the first brake rod 1301 is rotatably connected to the first fixed shaft 1303, and the first fixed shaft 1303 is fixedly connected to the rotating disk 1102; the second end of the second brake rod 1302 is rotatably connected to the second fixed shaft 1304, and the second fixed shaft 1304 is fixedly connected to the rotating disk 1102; a manual rod 1305 is arranged on the outer side of the second brake rod 1302, the first brake rod 1301, the second brake rod 1302 and the manual rod 1305 are all located on the same horizontal plane, and the manual rod 1305 also has two ends, the first end of which corresponds to the first end of the first brake rod 1301, and the second end corresponds to the second end of the first brake rod 1301; Figure 6 In the figure, the first ends of the first brake rod 1301, the second brake rod 1302 and the manual rod 1305 are all their respective right ends, and the second ends are all their respective left ends; the first end of the manual rod 1305 is rotatably connected to the second transmission rod 1308, and the second transmission rod 1308 is rotatably connected to the first end of the second brake rod 1302; the second end of the manual rod 1305 is rotatably connected to the first transmission rod 1306, and the first transmission rod 1306 is rotatably connected to the second end of the first brake rod 1301; the right end of the manual rod 1305 is rotatably connected to the third fixed shaft 1307, and the third fixed shaft 1307 is fixedly connected to the adjustment platform 10.

[0047] A spring 18 is arranged between the first end of the second brake rod 1302 and the first fixed shaft 1303; when the manual rod 1305 is not subjected to external force, the spring 18 is in a stretched state, and the turntable 1102 is squeezed and arranged between the first brake rod 1301 and the second brake rod 1302; the second brake rod 1302 and the first fixed shaft 1303 are both connected to the spring 18 through a connecting structure; the connecting structure includes a fixing block 14 fixedly connected to the second brake rod 1302 or the first fixed shaft 1303, and the shapes of the two fixing blocks 14 are different, so as to make the two ends of the spring 18 at the same height, because the top of the first fixed shaft 1303 is wrapped in the first brake rod 1301, and the fixing block 14 connected to the first fixed shaft 1303 It is L-shaped, and the upper part of the fixed block 14 corresponds to the fixed block 14 of the second brake rod 1302; the fixed block 14 is provided with a spherical groove 15, and a movable ball 16 protruding from the surface of the fixed block 14 is arranged in the spherical groove 15, and the diameter of the movable ball 16 is smaller than the diameter of the spherical groove 15, and the two ends of the spring 18 are respectively fixedly connected to the movable balls 16 corresponding to the second brake rod 1302 and the first fixed shaft 1303, and the connecting structure is arranged so that the spring 18 is not affected when the first brake rod 1301 and the second brake rod 1302 rotate, and the spring 18 does not interfere with the movement of the second brake rod 1302; the length of the manual rod 1305 is longer than that of the first brake rod 1301 and the second brake rod 1302, so as to facilitate the rotation of the manual rod 1305.

[0048] Because there are many types and sizes of gears, and the clamping forces that gears in different positions and with different functions can withstand are also very different, it may be troublesome to use a motor to drive and brake the positioning structure, and different gears require separate adjustment of the control system. Therefore, a braking structure is set up, and the staff can easily and instantly control the clamping force according to the force that different gears can withstand. The operation is convenient, and the clamping force can be adjusted at any time according to the processing conditions; by setting up the clamping structure, it can be adjusted according to the size of the inner and outer rings of the gear to ensure a larger contact range, improve the clamping effect, and avoid excessive clamping force due to a small clamping range, thereby causing gear wear; there are a variety of curvatures for the main board and extension plate, and different main boards and extension plates can be selected according to the size of the gear.

[0049] Working process: install the device on the gear processing table, place the gear 7 on the workbench 5, adjust the first lifting column 4 to make the workbench 5 to a suitable processing position, see whether to process the inner ring or the outer ring, remove the clamping structure, adjust the second lifting column 9 to make the upper surface of the movable block 1106 lower than the upper surface of the workbench 5; in the vertical direction, the turntable 1102 is located between the first fixed axis 1303 and the second fixed axis 1304; hold the second end of the manual rod 1305 and rotate it clockwise. After the manual rod 1305 rotates, its first end drives the first end of the second brake rod 1302 to rotate clockwise around the second fixed axis 1304, so that the second brake rod 1302 is disengaged from the turntable 1102; the second end of the manual rod 1305 simultaneously drives the first end of the first brake rod 1301 to rotate clockwise around the first fixed axis 1303, and the first brake rod 1301 is disengaged from the turntable 1102.

[0050] Hold the rotating handle 17 and rotate the turntable 1102. The rotation of the turntable 1102 drives the pillar 1103. The pillar 1103 drives the traction plate 1104. The traction plate 1104 drives the traction rod 1105. The traction rod 1105 drives the movable block 1106 to move to the inner ring or outer ring of the gear 7. Then release the manual rod 1305. Under the action of the spring 18, the first brake rod 1301 and the second brake rod 1302 tightly squeeze and fix the turntable 1102. Adjust the second lifting column 9 to lift the movable block 1106. If it does not need to be lifted, directly install the clamping structure on the movable block 1106. Then repeat the above operation to make the main board 1202 and the extension plate 1205 tightly squeeze the inner ring or outer ring of the gear 7. Release the manual rod 1305 to complete the fixation.

[0051] The above description is only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A combined fixture used for gearbox gear processing, characterized in that: It comprises a support seat, a clamping structure (12) arranged on the support seat for fixing the gear (7), and a positioning structure (11) for driving the clamping structure (12) to move; The support base comprises a base (1), a workbench (5) located above the base (1), and a first lifting column (4) connected to the base (1) and the workbench (5); The upper surface of the base (1) is provided with a lifting structure, and the upper surface of the lifting structure is provided with a positioning structure (11); the positioning structure (11) comprises a fixed column (1101) fixed to the top of the lifting structure, the top of the fixed column (1101) is rotatably connected to a turntable (1102), the upper surface of the turntable (1102) is fixedly connected to a support (1103), the top of the support (1103) is fixedly connected to a traction plate (1104), the traction plate (1104) is rotatably connected to a plurality of traction rods (1105) equidistantly along the circumferential direction, and each of the traction rods (1105) is rotatably connected to a movable block (1106); The workbench (5) is provided with a plurality of clamping channels (8) at equal intervals along the circumferential direction, and the movable block (1106) is located in the clamping channel (8) and is slidably connected thereto.

2. The combined fixture for gearbox gear processing according to claim 1, characterized in that: The bottom of the base (1) is provided with a slot structure (2) or a top structure (201) or a sleeve structure (202) or a flange structure (203).

3. The combined fixture for gearbox gear machining according to claim 1, characterized in that: The lifting structure comprises a second lifting column (9) fixed on the upper surface of the base (1), and an adjustment platform (10) fixed on the top of the second lifting column (9).

4. The combined fixture for gearbox gear processing according to claim 1, characterized in that: The clamping structure (12) comprises a connecting screw (1201) threadedly connected to the movable block (1106), and a main board (1202) threadedly connected to the connecting screw (1201).

5. The combined fixture for gearbox gear processing according to claim 4, characterized in that: An extension plate (1205) is detachably connected to the side of the main board (1202); there are a plurality of extension plates (1205), and the plurality of extension plates (1205) are detachably connected in sequence.

6. The combined fixture for gearbox gear machining according to claim 5, characterized in that: The main board (1202) and the extension board (1205) are both arc-shaped.

7. The combined fixture for gearbox gear machining according to claim 1, characterized in that: The adjustment platform (10) is provided with a braking structure (13) for fixing the rotating disk (1102).

8. The combined fixture for gearbox gear processing according to claim 7, characterized in that: The braking structure (13) comprises a first brake rod (1301) and a second brake rod (1302) symmetrically arranged on the outside of the rotating disk (1102) and in contact with the rotating disk; a first end of the first brake rod (1301) is rotatably connected to a first fixed shaft (1303), and the first fixed shaft (1303) is fixedly connected to the rotating disk (1102); a second end of the second brake rod (1302) is rotatably connected to a second fixed shaft (1304), and the second fixed shaft (1304) is fixedly connected to the rotating disk (1102); a second brake rod (1302) is arranged on the outside of the second brake rod (1302). There is a manual rod (1305), the first end of the manual rod (1305) is rotatably connected to the second transmission rod (1308), and the second transmission rod (1308) is rotatably connected to the first end of the second brake rod (1302); the second end of the manual rod (1305) is rotatably connected to the first transmission rod (1306), and the first transmission rod (1306) is rotatably connected to the second end of the first brake rod (1301); the manual rod (1305) is rotatably connected to a third fixed shaft (1307), and the third fixed shaft (1307) is fixedly connected to the adjustment platform (10).

9. The combined fixture for gearbox gear machining according to claim 8, characterized in that: A spring (18) is arranged between the first end of the second brake rod (1302) and the first fixed shaft (1303); when the manual rod (1305) is not subjected to external force, the spring (18) is in a stretched state, and the rotating disk (1102) is squeezed and arranged between the first brake rod (1301) and the second brake rod (1302); the second brake rod (1302) and the first fixed shaft (1303) are both connected to the spring (18) via a connecting structure; the connecting structure It comprises a fixed block (14) fixedly connected to the second brake rod (1302) or the first fixed shaft (1303); the fixed block (14) is provided with a spherical groove (15), a movable ball (16) is arranged in the spherical groove (15), the diameter of the movable ball (16) is smaller than the diameter of the spherical groove (15), and the two ends of the spring (18) are respectively fixedly connected to the movable balls (16) corresponding to the second brake rod (1302) and the first fixed shaft (1303).

10. The combined fixture for gearbox gear processing according to claim 1, characterized in that: The rotating disk (1102) is fixedly mounted with a rotating handle (17); baffles (801) are vertically arranged on the lower surface of the workbench (5) at positions on both sides of the clamping channel (8); and a plurality of annular and concentric sink grooves (802) are provided on the upper surface of the workbench (5).

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