Positioning device for right-angle milling head spindle of numerical control boring and milling machine and assembling and operating method

Abstract

The invention provides a numerical control boring and milling machine right-angle milling head spindle positioning device and an assembly operation method. The spindle positioning device comprises a positioning block, a plug pin is horizontally installed in the positioning block in a sliding mode, the tail end of the plug pin is sleeved with a spring used for resetting, and the spring is limited in the positioning block through an end cover; a first plane groove is machined in the plug pin, and an inclined sliding groove is machined in the first plane groove. A pressing rod is vertically installed in the positioning block in a sliding mode, a second plane groove used for being matched with the first plane groove is machined in the bottom end of the pressing rod, a bearing is installed on the second plane groove through a cylindrical pin, the bearing is in sliding fit with the inclined sliding groove, and the horizontal telescopic motion of the plug pin is driven through the lifting motion of the pressing rod. The device can be used for positioning the milling head main shaft of a heavy numerical control boring and milling machine and a gantry milling machine accessory, so that reliable positioning of the milling head main shaft is realized, and the device is stable and reliable in operation and low in manufacturing cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of numerical control machine tools, and mainly relates to a spindle positioning device and an assembly operation method for a right-angle milling head of a numerically controlled boring and milling machine. Background Art

[0002] For heavy-duty numerically controlled boring and milling machines or gantry mills to expand their processing performance and achieve five-sided machining, they are usually equipped with right-angle milling heads and universal milling heads. The machine tool spindle and the accessory milling head should be accurately docked. At the same time, in order to reduce the docking time, the accessory milling head should have an automatic spindle positioning function.

[0003] The structural form commonly adopted by the spindle positioning mechanism at present is to use the milling head housing as the main body and install relevant moving parts in combination. The advantage of this structure is that it is overall compact, but the disadvantage is that the layout of the milling head housing is complex, the processing accuracy requirements are high, and it is not convenient for installation, disassembly and maintenance. Moreover, as the use time prolongs, the wear gap between the milling head housing and the moving parts increases, resulting in a decrease in the spindle positioning accuracy, and it is easy to damage the machine tool spindle and the accessory milling head due to misalignment. The repair process has a long cycle and high costs. Summary of the Invention

[0004] To solve the above technical problems, the object of the present invention is to provide a spindle positioning device and an assembly operation method for a right-angle milling head of a numerically controlled boring and milling machine. This device can be used for spindle positioning of the accessory milling head of a heavy-duty numerically controlled boring and milling machine and a gantry mill, thereby realizing reliable positioning of the milling head spindle. Moreover, this device operates stably and reliably and has a low manufacturing cost.

[0005] To achieve the above technical features, the object of the present invention is realized as follows: A spindle positioning device for a right-angle milling head of a numerically controlled boring and milling machine, the spindle positioning device includes a positioning block, an insertion pin is horizontally slidably installed inside the positioning block, a spring for resetting is sleeved at the tail end of the insertion pin, and the spring is limited inside the positioning block by an end cap; A first flat groove is machined on the insertion pin, and an inclined sliding groove is machined on the first flat groove; A pressure rod is vertically slidably installed inside the positioning block, a second flat groove for cooperating with the first flat groove is machined at the bottom end of the pressure rod, a bearing is installed on the second flat groove through a cylindrical pin, the bearing forms a sliding fit with the inclined sliding groove, and the horizontal telescopic movement of the insertion pin is driven by the lifting movement of the pressure rod.

[0006] Preferably, the positioning block includes a positioning block main body, mounting ear plates are symmetrically arranged on both sides of the top end of the positioning block main body, a first stepped bolt hole and a first positioning pin hole are machined on the mounting ear plates, a first blind hole for installing the pressure rod is vertically machined inside the positioning block main body, a pin hole for installing the insertion pin is horizontally penetrated and machined inside the positioning block main body, a part of the inner wall of the pin hole penetrates through the first blind hole, a end cap installation groove is machined at the tail of one side of the pin hole, and a first bolt hole is machined on the end cap installation groove.

[0007] Preferably, the position where the end - cover mounting groove is located is used for mounting the end - cover, and the end - cover is fixed by socket - head cap screws that match the first bolt holes.

[0008] Preferably, the plug pin includes a plug - pin rod. A conical tip is provided at one end of the head of the plug - pin rod, a spring positioning post is provided at the other end of the tail of the plug - pin rod. A first flat groove is machined on the plug - pin rod. A second bolt hole is machined at the center of the tail end of the spring positioning post, and the diameter of the spring positioning post is smaller than that of the plug - pin rod.

[0009] Preferably, the pressure rod includes a pressure - rod body. A second flat groove is machined at the bottom end of the pressure - rod body. A pin hole is machined on the second flat groove, and a cylindrical pin is fixedly installed in the pin hole. A third bolt hole is machined at the top end of the pressure - rod body.

[0010] Preferably, the end - cover includes an end - cover body. Second stepped bolt holes arranged in a circle are machined on the end - cover body, and the second stepped bolt holes are used to cooperate with socket - head cap screws. A spring positioning cavity for positioning the spring is machined on the inner end face of the end - cover body.

[0011] Preferably, the bearing adopts a powder - metallurgy copper - based bearing.

[0012] Preferably, during installation, the spindle positioning device is fixed on the right - angle milling head housing through a positioning pin and socket - head cap screws.

[0013] On the other hand, the present invention provides an assembly and operation method for the spindle positioning device of a right - angle milling head of a CNC boring and milling machine, including: Assembly of the spindle positioning device: It is carried out after the internal assembly of the right - angle milling head is completed. Position the positioning block with a positioning pin and fasten it on the shoulder surface of the right - angle milling head housing with socket - head cap screws. Pre - assemble the pressure rod, cylindrical pin and bearing into a component; horizontally insert the plug pin and vertically insert the pressure - rod component. After the two are matched, install the spring and end - cover in sequence and fasten them with socket - head cap screws; press down the pressure rod, align the plug pin with the V - shaped groove of the milling head combination key block and then release it. The plug pin is automatically positioned. At this time, the end - face key groove on the combination key block will be in the horizontal zero position, and the pressure rod will reset to the uppermost end of its stroke under the action of the spring; Operation process: Adjust the relative position between the right - angle milling head and the machine tool spindle. The spindle stops accurately at the zero position and slowly approaches the right - angle milling head housing. The end - cover of the ram first contacts the pressure rod and presses it down. The bearing on the pressure rod pushes the plug pin to move backward through the inclined groove, the spring is compressed, and the plug pin gradually disengages from the combination key block. At the same time, the key at the end of the boring - machine milling shaft slowly inserts into the end - face key groove on the combination key block. When the end - cover of the ram fits with the end face of the right - angle milling head housing, the feed of the boring - machine ram stops, and the spindle positioning step of the right - angle milling head is completed; The disengagement process is as follows: The main shaft stops at the zero position. After the ram end cover moves away from the end face of the right-angle milling head housing, the spring pushes the pressure rod upward through the plug pin, bearing, and cylindrical pin. The plug pin continues to move forward and inserts into the V-shaped groove of the combined key block for positioning. The key at the end of the milling shaft of the boring machine gradually disengages from the end face keyway of the combined key block until it is completely disengaged.

[0014] Preferably, it also includes a replacement method for the main shaft positioning device. When the relevant moving parts of the main shaft positioning device are worn and the clearance is too large to accurately position, the module needs to be replaced. First, remove the hexagon socket head cap screws and the end cover, remove the spring, pull out the pressure rod and the plug pin, and finally remove the positioning pin and the hexagon socket head bolts to remove the positioning block, and then replace it with a new main shaft positioning device.

[0015] The present invention has the following beneficial effects: 1. The milling head main shaft positioning device of the present invention simplifies the design of the right-angle milling head housing, reduces its processing difficulty, eliminates the wear between the main shaft positioning moving parts and the milling head housing, and extends the service life of the important part, the milling head housing. It has a simple structure, low manufacturing cost, accurate and reliable positioning, and is easy to replace.

[0016] 2. The milling head main shaft positioning device of the present invention can form different specifications and models according to the type and external dimensions of the attached milling head, and can be widely used for the automatic positioning of the main shafts of medium and large-sized attached right-angle milling heads and universal milling heads, having a certain universality.

[0017] 3. Through the above-mentioned positioning block as the installation basis of the whole device.

[0018] 4. Through the above-mentioned plug pin, it can be used in cooperation with the pressure rod, and then drive the telescopic movement of the plug pin through the lifting of the pressure rod, and realize the reset of the plug pin through the spring.

[0019] 5. Through the above-mentioned pressure rod, it can be used to overcome the elastic force of the spring, and then drive the telescopic movement of the plug pin.

[0020] 6. Through the above-mentioned end cover, it can be used to limit the spring and facilitate the subsequent installation of the plug pin after disassembly.

[0021] 7. Through the bearing, a good lubrication effect is achieved, the friction force is reduced, and the smoothness of the sliding is ensured. Description of the Drawings

[0022] The following further describes the present invention in conjunction with the drawings and embodiments.

[0023] Figure 1 It is a three-dimensional sectional view of the main shaft positioning device of the present invention.

[0024] Figure 2 It is a top view of the main shaft positioning device of the present invention.

[0025] Figure 3 For the present inventionFigure 2 A-A view of the main spindle positioning device.

[0026] Figure 4 For the present invention Figure 2 B-B view of the main spindle positioning device.

[0027] Figure 5 Main perspective view of the main spindle positioning device of the present invention.

[0028] Figure 6 Front view of the combined installation of the main spindle positioning device of the present invention and a right-angle milling head.

[0029] Figure 7 Partial connection view of the combined installation drawing of the main spindle positioning device of the present invention and a right-angle milling head.

[0030] Figure 8 Top view of the positioning block of the present invention.

[0031] Figure 9 Front view of the positioning block of the present invention.

[0032] Figure 10 For the present invention Figure 8 C-C view of the positioning block.

[0033] Figure 11 For the present invention Figure 9 D-D view of the positioning block.

[0034] Figure 12 3D view of the positioning block of the present invention.

[0035] Figure 13 Front view of the pressure bar of the present invention.

[0036] Figure 14 Side view of the pressure bar of the present invention.

[0037] Figure 15 3D view of the pressure bar of the present invention.

[0038] Figure 16 Front view of the plug pin of the present invention.

[0039] Figure 17 Top view of the plug pin of the present invention.

[0040] Figure 18 3D view of the plug pin of the present invention.

[0041] Figure 19 Front view of the end cap of the present invention.

[0042] Figure 20 For the present invention Figure 19 E-E view of the end cap.

[0043] Figure 21 This is the 3D drawing of the end cover of the present invention.

[0044] In the figure: spring 1, hexagon socket head screw 2, bearing 3, cylindrical pin 4, plug pin 5, end cover 6, pressure bar 7, positioning block 8, ram end cover 9, key for milling shaft end of boring machine 10, combined key block 11, spindle positioning device 12, right angle milling head housing 13, positioning pin 14, hexagon socket head bolt 15; Plug pin rod 501, conical tip 502, first flat groove 503, inclined chute 504, spring positioning column 505, second bolt hole 506; Pressure bar body 701, second flat groove 702, pin hole 703, third bolt hole 704; Positioning block body 801, end cover mounting groove 802, first bolt hole 803, first stepped bolt hole 804, mounting ear plate 805, first positioning pin hole 806, first blind hole 807, plug pin hole 808. Detailed implementation mode

[0045] The following further describes the implementation mode of the present invention in conjunction with the attached drawings.

[0046] Embodiment 1: Refer to Figure 1-21 , for the spindle positioning device of the right angle milling head of a CNC boring and milling machine, the spindle positioning device 12 includes a positioning block 8, a plug pin 5 is horizontally slidably installed inside the positioning block 8, a spring 1 for resetting is sleeved on the tail end of the plug pin 5, and the spring 1 is limited inside the positioning block 8 by the end cover 6; a first flat groove 503 is machined on the plug pin 5, and an inclined chute 504 is machined on the first flat groove 503; a pressure bar 7 is vertically slidably installed inside the positioning block 8, a second flat groove 702 for cooperating with the first flat groove 503 is machined at the bottom end of the pressure bar 7, a bearing 3 is installed on the second flat groove 702 through a cylindrical pin 4, the bearing 3 forms a sliding fit with the inclined chute 504, and the horizontal telescopic movement of the plug pin 5 is driven by the lifting action of the pressure bar 7. This device can be used for the spindle positioning of a heavy-duty CNC boring and milling machine and the milling head attachment of a gantry milling machine, thereby realizing the reliable positioning of the milling head spindle. Moreover, this device operates stably and reliably, and has a low manufacturing cost. During the specific use process, by driving the pressure bar 7, the pressure bar 7 will drive the plug pin 5 to horizontally telescopic move, the plug pin 5 continues to move forward and inserts into the V-shaped groove of the combined key block 11 for positioning, thereby realizing its positioning. When the pressure bar 7 is released, the plug pin 5 will complete the reset and disengage from the lock under the action of the spring 1.

[0047] Further, the positioning block 8 includes a positioning block main body 801. Mounting lugs 805 are symmetrically arranged on both sides of the top end of the positioning block main body 801. A first stepped bolt hole 804 and a first positioning pin hole 806 are machined on the mounting lugs 805. A first blind hole 807 for mounting the pressure rod 7 is vertically machined inside the positioning block main body 801. A pin hole 808 for mounting the insertion pin 5 is horizontally and penetratingly machined inside the positioning block main body 801. The part of the inner wall of the first blind hole 807 is penetrated by the pin hole 808. An end cover mounting groove 802 is machined at one side tail of the pin hole 808. A first bolt hole 803 is machined on the end cover mounting groove 802. The above-mentioned positioning block 8 serves as the installation foundation of the entire device.

[0048] Further, the position where the end cover mounting groove 802 is located is used for mounting the end cover 6. The end cover 6 is fixed by an internal hexagonal screw 2 that mates with the first bolt hole 803. Through the above installation structure, the reliable positioning and installation of the end cover 6 are ensured.

[0049] Further, the insertion pin 5 includes an insertion pin rod 501. A conical tip 502 is provided at one end of the head of the insertion pin rod 501. A spring positioning post 505 is provided at one end of the tail of the insertion pin rod 501. A first flat groove 503 is machined on the insertion pin rod 501. A second bolt hole 506 is machined at the center of the tail end of the spring positioning post 505. The diameter of the spring positioning post 505 is smaller than the diameter of the insertion pin rod 501. Through the above insertion pin 5, it can be used to cooperate with the pressure rod 7, and then drive the expansion and contraction of the insertion pin 5 by the lifting of the pressure rod 7, and the insertion pin 5 is reset by a spring.

[0050] Further, the pressure rod 7 includes a pressure rod main body 701. A second flat groove 702 is machined at the bottom end of the pressure rod main body 701. A pin hole 703 is machined on the second flat groove 702. A cylindrical pin 4 is fixedly installed in the pin hole 703. A third bolt hole 704 is machined at the top end of the pressure rod main body 701. Through the above pressure rod 7, it can be used to overcome the spring force, and then drive the expansion and contraction of the insertion pin 5.

[0051] Further, the end cover 6 includes an end cover main body 601. Second stepped bolt holes 602 arranged in a circle are machined on the end cover main body 601. The second stepped bolt holes 602 are used to cooperate with the internal hexagonal screws 2. A spring positioning cavity 603 for positioning the spring 1 is machined on the inner end face of the end cover main body 601. Through the above end cover 6, it can be used to limit the spring 1 and facilitate the subsequent installation of the insertion pin 5 after disassembly.

[0052] Further, the bearing 3 is a powder metallurgy copper-based bearing. The bearing 3 has a good lubrication effect, reduces the friction force, and ensures the smoothness of sliding.

[0053] Further, during installation, the spindle positioning device 12 is fixed to the right-angle milling head housing 13 by a positioning pin 14 and an Allen bolt 15. The above installation structure facilitates the subsequent fixation of the spindle positioning device 12.

[0054] Embodiment 2: The present invention provides an assembly and operation method for a spindle positioning device of a right-angle milling head of a CNC boring and milling machine, including: Assembly of the spindle positioning device 12: It is carried out after the internal assembly of the right-angle milling head is completed. Position the positioning block 8 with a positioning pin 14 and fasten it to the shoulder surface of the right-angle milling head housing 13 with an Allen bolt 15. Pre-assemble the pressure rod 7, cylindrical pin 4, and bearing 3 into a component; horizontally insert the plug pin 5 and vertically insert the pressure rod 7 component. After the two are fitted, sequentially insert the spring 1 and end cover 6, and fasten them with Allen screws 2; press down the pressure rod 7, align the plug pin 5 with the V-shaped groove of the milling head combination key block 11 and then release it. The plug pin 5 automatically positions itself. At this time, the end face key groove on the combination key block 11 will be in the horizontal zero position, and the pressure rod 7 will reset to the uppermost end of its stroke under the action of the spring 1; Operation process: Adjust the relative position between the right-angle milling head and the machine tool spindle. The spindle is accurately stopped at the zero position and slowly approaches the right-angle milling head housing 13. The ram end cover 9 first contacts the pressure rod 7 and presses it down. The bearing 3 on the pressure rod 7 pushes the plug pin 5 to move backward through the inclined groove, the spring 1 is compressed, and the plug pin 5 gradually disengages from the combination key block 11. At the same time, the milling shaft end key 10 of the boring machine slowly inserts into the end face key groove on the combination key block 11. When the ram end cover 9 fits with the end face of the right-angle milling head housing 13, the ram of the boring machine stops feeding, and the spindle positioning step of the right-angle milling head is completed; The disengagement process is as follows: The spindle stops at the zero position. After the ram end cover 9 leaves the end face of the right-angle milling head housing 13 and moves backward, the spring 1 pushes the pressure rod 7 to move upward through the plug pin 5, bearing 3, and cylindrical pin 4. The plug pin 5 continues to move forward and inserts into the V-shaped groove of the combination key block 11 for positioning. The milling shaft end key 10 of the boring machine gradually disengages from the end face key groove of the combination key block 11 until it is completely disengaged.

[0055] Further, it also includes a replacement method for the spindle positioning device 12. When the relevant moving parts of the spindle positioning device 12 are worn and the clearance is too large to accurately position, the module needs to be replaced; first, remove the Allen screw 2 and end cover 6, remove the spring 1, pull out the pressure rod 7 and plug pin 5, and finally remove the positioning pin 14 and Allen bolt 15 to remove the positioning block 8, and then replace it with a new spindle positioning device 12.

Claims

1. A spindle positioning device for a right-angle milling head of a CNC boring and milling machine, characterized in that, The spindle positioning device (12) includes a positioning block (8). An insertion pin (5) is horizontally and slidably installed inside the positioning block (8). A spring (1) for resetting is sleeved at the tail end of the insertion pin (5). The spring (1) is limited inside the positioning block (8) by an end cover (6). A first flat groove (503) is machined on the insertion pin (5), and an inclined sliding groove (504) is machined on the first flat groove (503). A pressure rod (7) is vertically and slidably installed inside the positioning block (8). A second flat groove (702) for cooperating with the first flat groove (503) is machined at the bottom end of the pressure rod (7). A bearing (3) is installed on the second flat groove (702) through a cylindrical pin (4). The bearing (3) forms a sliding fit with the inclined sliding groove (504), and the horizontal telescopic movement of the insertion pin (5) is driven by the lifting movement of the pressure rod (7).

2. The spindle positioning device of the right-angle milling head of the numerically controlled boring and milling machine according to claim 1, characterized in that: The positioning block (8) includes a positioning block main body (801). Mounting ear plates (805) are symmetrically arranged on both sides of the top end of the positioning block main body (801). A first stepped bolt hole (804) and a first positioning pin hole (806) are machined on the mounting ear plates (805). A first blind hole (807) for installing the pressure rod (7) is vertically machined inside the positioning block main body (801). A pin hole (808) for installing the insertion pin (5) is horizontally and penetratingly machined inside the positioning block main body (801). The part of the inner wall of the pin hole (808) that penetrates the first blind hole (807) is provided. A tail end on one side of the pin hole (808) is machined with an end cover installation groove (802), and a first bolt hole (803) is machined on the end cover installation groove (802).

3. The positioning device for the spindle of the right-angle milling head of the numerically controlled boring and milling machine according to claim 2, characterized in that: The position where the end cover installation groove (802) is located is used to install the end cover (6). The end cover (6) is fixed by an internal hexagonal screw (2) that cooperates with the first bolt hole (803).

4. The positioning device for the spindle of the right-angle milling head of the numerically controlled boring and milling machine according to claim 1, characterized in that: The insertion pin (5) includes an insertion pin rod (501). A conical tip (502) is provided at one end of the head of the insertion pin rod (501). A spring positioning column (505) is provided at one end of the tail of the insertion pin rod (501). A first flat groove (503) is machined on the insertion pin rod (501). A second bolt hole (506) is machined at the center of the tail end of the spring positioning column (505). The diameter of the spring positioning column (505) is smaller than the diameter of the insertion pin rod (501).

5. The positioning device for the spindle of the right-angle milling head of the numerically controlled boring and milling machine according to claim 4, characterized in that: The pressure rod (7) includes a pressure rod main body (701). A second flat groove (702) is machined at the bottom end of the pressure rod main body (701). A pin hole (703) is machined on the second flat groove (702). The cylindrical pin (4) is fixedly installed on the pin hole (703). A third bolt hole (704) is machined at the top end of the pressure rod main body (701).

6. The positioning device for the spindle of the right-angle milling head of the numerically controlled boring and milling machine according to claim 3, characterized in that: The end cover (6) includes an end cover main body (601). Second stepped bolt holes (602) arranged in a circumferential pattern are machined on the end cover main body (601). The second stepped bolt holes (602) are used to cooperate with the internal hexagonal screws (2). A spring positioning cavity (603) for positioning the spring (1) is machined on the inner end face of the end cover main body (601).

7. The positioning device for the spindle of the right-angle milling head of the numerically controlled boring and milling machine according to claim 3, characterized in that: The bearing (3) uses a powder metallurgy copper-based bearing.

8. The positioning device for the spindle of the right-angle milling head of the numerically controlled boring and milling machine according to claim 1, characterized in that: During installation, the spindle positioning device (12) is fixed to the right-angle milling head housing (13) by a positioning pin (14) and an Allen bolt (15).

9. The assembly and operation method of the spindle positioning device of the right-angle milling head of the numerically controlled boring and milling machine according to any one of claims 1-8, characterized in that, It includes: Assembly of the spindle positioning device (12): This is carried out after the internal assembly of the right-angle milling head is completed. Position the positioning block (8) with the positioning pin (14), and fasten it to the shoulder surface of the right-angle milling head housing (13) with an Allen bolt (15). Pre-assemble the pressure rod (7), cylindrical pin (4), and bearing (3) into a component; horizontally insert the plug pin (5), vertically insert the pressure rod (7) component, and then sequentially insert the spring (1) and end cap (6) after they are fitted together, and fasten them with an Allen screw (2); press down the pressure rod (7), align the plug pin (5) with the V-shaped groove of the milling head combination key block (11) and then release it. The plug pin (5) will be automatically positioned. At this time, the end face key groove on the combination key block (11) will be at the horizontal zero position, and the pressure rod (7) will reset to the uppermost end of its stroke under the action of the spring (1). During operation: Adjust the relative position between the right-angle milling head and the machine tool spindle. The spindle stops accurately at the zero position and slowly approaches the right-angle milling head housing (13). The ram end cap (9) first contacts the pressure rod (7) and presses it down. The bearing (3) on the pressure rod (7) pushes the plug pin (5) to move backward through the inclined groove, the spring (1) is compressed, and the plug pin (5) gradually disengages from the combination key block (11). At the same time, the milling shaft end key (10) of the boring machine slowly inserts into the end face key groove on the combination key block (11). When the ram end cap (9) fits with the end face of the right-angle milling head housing (13), the feed of the boring machine ram stops, and the positioning step of the right-angle milling head spindle is completed. The disengagement process is as follows: The spindle stops at the zero position. After the ram end cap (9) leaves the end face of the right-angle milling head housing (13) and moves backward, the spring (1) pushes the pressure rod (7) to move upward through the plug pin (5), bearing (3), and cylindrical pin (4). The plug pin (5) continues to move forward and inserts into the V-shaped groove of the combination key block (11) for positioning. The milling shaft end key (10) of the boring machine gradually disengages from the end face key groove of the combination key block (11) until it is completely disengaged.

10. The assembly and operation method of the spindle positioning device of the right-angle milling head of the numerically controlled boring and milling machine according to claim 9, characterized in that, It also includes a method for replacing the spindle positioning device (12). When the relevant moving parts of the spindle positioning device (12) are worn and the clearance is too large to accurately position, the module needs to be replaced; first, remove the Allen screw (2) and end cap (6), remove the spring (1), pull out the pressure rod (7) and plug pin (5), and finally remove the positioning pin (14) and Allen bolt (15) to remove the positioning block (8), and then replace it with a new spindle positioning device (12).

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