Lifting equipment for maintenance of compressor

Abstract

The invention provides lifting equipment for compressor maintenance, and relates to the technical field of lifting equipment, the lifting equipment comprises two supporting frames, a connecting column is fixedly mounted at the upper end of each supporting frame, a cross rod is fixedly mounted at the upper ends of the connecting columns on the two sides, and first sliding rails are arranged on the two sides of the cross rod respectively; a plurality of hoisting assemblies used for hoisting a compressor are slidably installed in the first sliding rails, a quick disassembling assembly used for quickly disassembling and assembling the hoisting assemblies is installed in the middle of the transverse rod, supporting feet are installed at the bottoms of the supporting frames on the two sides, and moving assemblies used for moving equipment are installed in the supporting frames on the two sides. According to the hoisting equipment, through cooperation of the quick disassembly assembly and the hoisting assemblies, the multiple hoisting assemblies can be quickly taken out only by rotating the first rotary knob, compared with existing hoisting equipment, the multiple hoisting assemblies can be quickly taken out, one-by-one disassembly by an operator is not needed, during installation, only the hoisting assemblies need to be quickly inserted, and combined insertion blocks need to be closed; and the maintenance efficiency is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of lifting equipment, and in particular to a lifting equipment for compressor maintenance. Background Art

[0002] Compressors may fail after long-term use. When repairing compressors, due to the different sizes of compressors, it is necessary to use a lifting device to lift the compressor for the convenience of repair when repairing a larger compressor. For example, patent announcement number CN209721410U is a lifting device for mechanical equipment maintenance, including a keel and two bottom plates, and the left and right sides of the keel are fixedly installed with support frames, and the support frames include a first support plate and a second support plate, and the first support plate is movably installed on the side away from the keel. The lifting device for mechanical equipment maintenance is provided with a lifting rope, a positioning plate, a hollow rod and a positioning inner rod. The user connects the mechanical equipment to be lifted through a hook device, turns on the lifting motor, and the lifting motor drives the winding rod to rotate and reel in the lifting rope to pull the mechanical equipment to be lifted up, and the positioning inner rod shrinks into the hollow rod. The hollow rod and the positioning inner rod restrict the positioning plate from shaking. In this way, when lifting the mechanical equipment, the mechanical equipment will not shake, eliminating the troubles of the user and facilitating the troubles of the user.

[0003] However, when the existing lifting equipment is in continuous use, the lifting rope needs to be replaced and maintained. When the existing lifting equipment is disassembled, the lifting device needs to be removed from the bracket. When multiple lifting devices are disassembled, different lifting devices need to be disassembled frequently, which makes maintenance more cumbersome. For this reason, the present application designs a lifting equipment for compressor maintenance, which can quickly replace the rope and maintain the lifting device. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a lifting device for compressor maintenance, which solves the problem that the existing lifting equipment is relatively cumbersome when maintaining the lifting tools.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A lifting device for compressor maintenance comprises two support frames, each of which has a connecting column fixedly mounted on the upper end, a cross bar fixedly mounted on the upper ends of the connecting columns on both sides, first slide rails are respectively arranged on both sides of the cross bar, a plurality of lifting components for lifting the compressor are slidably mounted inside the first slide rails, a quick-release component for quickly disassembling and assembling the lifting components is installed in the middle of the cross bar, supporting feet are installed at the bottom of the support frames on both sides, and moving components for moving equipment are installed inside the support frames on both sides.

[0007] Preferably, the quick-release assembly includes a combination slot, which is opened in the middle of the cross bar, and a combination plug-in block is slidably installed inside the combination slot. Second slide rails are arranged on both sides of the combination plug-in block, and the second slide rails are aligned with the first slide rails on both sides.

[0008] Preferably, a first screw hole is penetrated through the upper middle side of the cross bar, a first screw rod is threadedly installed inside the first screw hole, a first knob is fixedly installed on the upper end of the first screw rod, and the lower end of the first screw rod is rotatably connected to the upper surface of the combined plug block.

[0009] Preferably, the movable component includes a plurality of movable through holes, which are opened through the bottom of the support frame, each of which is provided with a movable seat, each of which is provided with a rotating seat at the bottom, and each of which is provided with a movable pulley rotatably installed inside.

[0010] Preferably, a connecting rod is commonly installed on the upper end of the movable seat on each side, a limiting seat is fixedly installed in the middle of the connecting rod, a movable through hole is opened in the middle of the support frame, and the limiting seat is located inside the movable through hole.

[0011] Preferably, a second screw hole is opened inside the limit seat, a second screw rod is rotatably installed inside the movable through hole, a second knob is fixedly installed on the upper side of the second screw rod, and the second screw rod shaft is threadably matched with the second screw hole.

[0012] Preferably, an expansion frame is fixedly mounted on the outer side of each movable seat, and an auxiliary pulley is rotatably mounted inside each expansion frame.

[0013] Preferably, the lifting assembly includes a component frame, a connecting slide is installed on the upper end of the component frame, the connecting slide is slidably matched with the first slide rail, extension frames are respectively provided on both sides of the component frame, support rollers are rotatably installed inside the extension frames through bearing seats, lifting ropes are arranged on the outer sides of the support rollers on both sides, and a falling roller is movably provided at the lower end of the lifting rope, a placement seat is installed on the outer side of the falling roller, and a connecting lifting plate is fixedly installed on the bottom of the placement seat.

[0014] Preferably, a rotating disk is rotatably arranged in the middle of the component frame, and a first wire drum and a second wire drum for reeling in and releasing the wire are respectively installed on the upper ends of the rotating disk, the wire groove diameter of the first wire drum is larger than the wire groove diameter of the second wire drum, the interiors of the first wire drum and the second wire drum are respectively connected to the two ends of the lifting rope, and the winding directions of the lifting ropes inside the first wire drum and the second wire drum are opposite.

[0015] Preferably, an extension column is fixedly mounted on the bottom of the rotating disk, and a plurality of toggle rods are fixedly mounted on the outer side of the extension column.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The first screw rod can be rotated by holding and rotating the first knob, and the first screw rod and the first screw hole are threadedly matched, wherein the first screw rod is rotatably connected to the upper surface of the combination plug block, so that the combination plug block can slide and adjust the upper and lower positions inside the combination slot, wherein when the combination plug block moves downward, the second slide rail and the first slide rails on both sides are staggered, and space for quickly removing the lifting components is reserved, so that the application only needs to rotate the first knob to realize the rapid removal of several lifting components. Compared with the existing lifting equipment, the application can quickly remove multiple lifting components without the need for operators to disassemble them one by one, and when installing, it only needs to quickly insert the lifting components and close the combination plug block, which greatly improves the maintenance efficiency;

[0018] Similarly, by rotating the first knob in the opposite direction, the combined plug block can be quickly raised so that the second slide rail is aligned with the first slide rails on both sides, so that the lifting component can move inside the second slide rail and the first slide rail to facilitate the distribution of different lifting component positions. The present application can accommodate several lifting components through the above structure, and the corresponding number of lifting components can be installed according to the lifting points, so that the present application can be used for lifting different similar compressors, further improving its scope of application.

[0019] 2. The second screw rod is rotated by turning the second knob. When the second screw rod rotates, its rod body will cooperate with the second screw hole thread, and the limit seat and the movable through hole are used to limit the cooperation, so that the limit seat can be moved downward and the movable seat can be moved downward by the connecting rod, so that several movable pulleys and auxiliary pulleys can contact the ground, and the support feet can be replaced to support the present application, so that the present application can be freely adjusted as needed to facilitate the movement of the present application, and stable support can also be provided during maintenance to ensure the stability of the lifting.

[0020] 3. The extension column can be driven to rotate by rotating the toggle lever, and the rotating disk can drive the first wire drum and the second wire drum above to rotate synchronously, wherein the wire groove diameters between the first wire drum and the second wire drum are different. When rotating clockwise, the lifting rope in the large wire groove is recovered, and the lifting rope in the small wire groove is released. In this process, the diameter difference is utilized to cause the mounting seat and the connecting lifting disk to rise, thereby lifting the compressor. Conversely, when rotating counterclockwise, the lifting rope in the large wire groove is released, and the lifting rope in the small wire groove is recovered, thereby lowering the compressor. Each lifting component is independently adjusted, so that when different lifting components are set, the present application can perform corresponding connection lifting according to the different lifting point heights of the compressor.

[0021] 4. In the present application, in order to enable the lifting assembly to cooperate with the quick-release assembly to achieve quick disassembly and assembly, a connecting slide is installed on the upper end of the assembly frame, wherein the connecting slide will slide with the first slide rail and the second slide rail to achieve position movement and quick disassembly and assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0023] Figure 2 It is a front view structural schematic diagram of the present invention;

[0024] Figure 3 yes Figure 2 Schematic diagram of the cross-section structure at AA in the middle;

[0025] Figure 4 It is a schematic diagram of the structure of the present invention when viewed from above;

[0026] Figure 5 yes Figure 4 Schematic diagram of the cross-section structure at BB in the middle;

[0027] Figure 6 yes Figure 4 Schematic diagram of the cross-section structure at CC;

[0028] Figure 7 It is a three-dimensional structural diagram of the lifting assembly;

[0029] Figure 8 It is a side view structural diagram of the hoisting assembly;

[0030] Fig. 9 yes Figure 8 Schematic diagram of the cross-section structure at DD in the middle;

[0031] Fig.10 It is a schematic diagram of the three-dimensional structure of the sliding component.

[0032] In the figure: 1, support frame; 2, connecting column; 3, cross bar; 4, first slide rail; 5, quick release assembly; 501, combination slot; 502, combination plug block; 503, first screw hole; 504, first screw rod; 505, first knob; 506, second slide rail; 6, lifting assembly; 601, assembly frame; 6011, connecting slide seat; 602, rotating disk; 6021, first wire drum; 6022, second wire drum; 603, extension frame; 6031, bearing seat; 6032, support Roller; 604, extension column; 6041, toggle rod; 605, lifting rope; 606, placement seat; 6061, falling roller; 607, connecting hanging plate; 7, support leg; 8, moving component; 801, movable through hole; 802, movable seat; 8021, rotating seat; 8022, moving pulley; 8023, auxiliary pulley; 8024, extension frame; 803, connecting rod; 804, limit seat; 8041, second screw hole; 805, second screw rod; 8051, second knob. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figures 1 to 10 As shown, a lifting device for compressor maintenance includes two support frames 1, a connecting column 2 is fixedly installed on the upper end of each support frame 1, a cross bar 3 is fixedly installed on the upper ends of the connecting columns 2 on both sides, first slide rails 4 are respectively arranged on both sides of the cross bar 3, a plurality of lifting components 6 for lifting the compressor are slidably installed inside the first slide rail 4, a quick-release component 5 for quickly disassembling and assembling the lifting components 6 is installed in the middle of the cross bar 3, supporting feet 7 are installed at the bottom of the support frames 1 on both sides, and moving components 8 for moving equipment are installed inside the support frames 1 on both sides.

[0035] In this embodiment, the quick-release assembly 5 includes a combination slot 501, which is opened in the middle of the cross bar 3. A combination plug-in block 502 is slidably installed inside the combination slot 501. Second slide rails 506 are arranged on both sides of the combination plug-in block 502, and the second slide rails 506 are aligned with the first slide rails 4 on both sides.

[0036] It should be noted that a first screw hole 503 is opened through the upper middle side of the cross bar 3, a first screw rod 504 is threadedly installed inside the first screw hole 503, a first knob 505 is fixedly installed on the upper end of the first screw rod 504, and the lower end of the first screw rod 504 is rotatably connected to the upper surface of the combined plug-in block 502.

[0037] By holding and rotating the first knob 505, the first screw rod 504 can be rotated, and the first screw rod 504 and the first screw hole 503 can be threadedly matched, wherein the first screw rod 504 is rotatably connected to the upper surface of the combination plug block 502, so that the combination plug block 502 can slide and adjust the upper and lower positions inside the combination slot 501, wherein when the combination plug block 502 moves downward, the second slide rail 506 will be staggered with the first slide rails 4 on both sides, and a space for quickly removing the hanging assembly 6 will be reserved, so that the present application only needs to rotate the first knob 505 to realize the rapid removal of several hanging assemblies 6. Compared with the existing lifting equipment, the present application can quickly remove multiple hanging assemblies 6 without the need for operators to disassemble them one by one, and during installation, it is only necessary to quickly insert the hanging assembly 6 and close the combination plug block 502, which greatly improves the maintenance efficiency;

[0038] Similarly, by rotating the first knob 505 in the opposite direction, the combined plug block 502 can be quickly raised so that the second slide rail 506 is aligned with the first slide rails 4 on both sides, so that the lifting component 6 can move inside the second slide rail 506 and the first slide rail 4 to facilitate the distribution of the positions of different lifting components 6. The present application can accommodate several lifting components 6 through the above structure, and the corresponding number of lifting components 6 can be installed according to the lifting points, so that the present application can be used for lifting different similar compressors, further improving its scope of application.

[0039] In this embodiment, the movable component 8 includes a plurality of movable through holes 801, and the movable through holes 801 are opened through the bottom of the support frame 1. A movable seat 802 is arranged inside each movable through hole 801, and a rotating seat 8021 is arranged at the bottom of each movable seat 802. A movable pulley 8022 is rotatably installed inside each rotating seat 8021, and an expansion frame 8024 is fixedly installed on the outside of each movable seat 802, and an auxiliary pulley 8023 is rotatably installed inside each extension frame 8024.

[0040] The upper end of each movable seat 802 is commonly equipped with a connecting rod 803, the middle of the connecting rod 803 is fixedly equipped with a limited seat 804, the middle of the support frame 1 is provided with a movable through hole 801, and the limited seat 804 is located inside the movable through hole 801;

[0041] A second screw hole 8041 is provided inside the limiting seat 804 , a second screw rod 805 is rotatably installed inside the movable through hole 801 , a second knob 8051 is fixedly installed on the upper side of the second screw rod 805 , and the shaft of the second screw rod 805 is threadedly matched with the second screw hole 8041 .

[0042] The second screw rod 805 is rotated by turning the second knob 8051. When the second screw rod 805 rotates, its rod body will be threadedly engaged with the second screw hole 8041, and the limit seat 804 and the movable through hole 801 are used to limit the cooperation, so that the limit seat 804 can be moved downward and the movable seat 802 can be moved downward by the connecting rod 803, so that several movable pulleys 8022 and auxiliary pulleys 8023 can contact the ground, and replace the support foot 7 to support the present application, so that the present application can be freely adjusted as needed to determine whether it can be moved, so as to facilitate the movement of the present application, and stable support can also be provided during maintenance to ensure the stability of the lifting.

[0043] In the present application, the lifting component 6 includes a component frame 601, a connecting slide 6011 is installed on the upper end of the component frame 601, the connecting slide 6011 is slidably matched with the first slide rail 4, and extension frames 603 are respectively provided on both sides of the component frame 601. Support rollers 6032 are rotatably installed inside the extension frame 603 through bearing seats 6031. Lifting ropes 605 are arranged on the outside of the support rollers 6032 on both sides. A falling roller 6061 is movably arranged at the lower end of the lifting rope 605. A placement seat 606 is installed on the outside of the falling roller 6061, and a connecting lifting plate 607 is fixedly installed on the bottom of the placement seat 606.

[0044] In the specific setting, a rotating disk 602 is rotatably arranged in the middle of the component frame 601, and the first wire drum 6021 and the second wire drum 6022 for reeling in and releasing the wire are respectively installed on the upper ends of the rotating disk 602. The wire groove diameter of the first wire drum 6021 is larger than the wire groove diameter of the second wire drum 6022. The interiors of the first wire drum 6021 and the second wire drum 6022 are respectively connected to the two ends of the lifting rope 605, and the winding directions of the lifting rope 605 inside the first wire drum 6021 and the second wire drum 6022 are opposite.

[0045] An extension column 604 is fixedly installed at the bottom of the rotating disk 602 , and a plurality of toggle rods 6041 are fixedly installed on the outer side of the extension column 604 .

[0046] By rotating the toggle lever 6041, the extension column 604 can be driven to rotate, and the rotating disk 602 can drive the first wire drum 6021 and the second wire drum 6022 above to rotate synchronously, wherein the wire groove diameters between the first wire drum 6021 and the second wire drum 6022 are different, and when rotating clockwise, the lifting rope 605 in the large wire groove is recovered, and the lifting rope 605 in the small wire groove is released, and in this process, the diameter difference is utilized to make the placement seat 606 and the connection hanging plate 607 rise, so as to lift the compressor, and vice versa, when rotating counterclockwise, the lifting rope 605 in the large wire groove is released, and the lifting rope 605 in the small wire groove is recovered, so as to lower the compressor, and each lifting assembly 6 is independently adjusted, so that when different lifting assemblies 6 are set, the corresponding connection lifting can be performed according to the different lifting point heights of the compressor;

[0047] In the present application, in order to enable the lifting assembly 6 to cooperate with the quick-release assembly 5 for quick assembly and disassembly, a connecting slide 6011 is installed on the upper end of the assembly frame 601, wherein the connecting slide 6011 will slide with the first slide rail 4 and the second slide rail 506, thereby achieving position movement and quick assembly and disassembly.

[0048] The working principle of this lifting equipment for compressor maintenance:

[0049] When in use, firstly, the second screw rod 805 is rotated by turning the second knob 8051. When the second screw rod 805 rotates, its rod body will be threadedly matched with the second screw hole 8041, wherein the limiting seat 804 is limitedly matched with the movable through hole 801, so that the limiting seat 804 can be moved downward and the movable seat 802 can be moved downward by the connecting rod 803, so that a plurality of movable pulleys 8022 and the auxiliary pulley 8023 can contact the ground, and the support leg 7 is replaced to support the present application, so that the present application can be quickly moved above the compressor without the need for personnel to check it in;

[0050] After being moved into place, the first screw rod 504 can be rotated by holding and rotating the first knob 505, and the first screw rod 504 and the first screw hole 503 are threadedly matched, wherein the first screw rod 504 is rotatably connected to the upper surface of the combination plug block 502, so that the combination plug block 502 can slide and adjust the upper and lower positions inside the combination slot 501, wherein when the combination plug block 502 moves downward, the second slide rail 506 will be staggered with the first slide rails 4 on both sides, and space for quickly installing the lifting component 6 will be reserved, and then the corresponding number of lifting components 6 will be installed according to the lifting needs;

[0051] After the installation is completed, the combined plug block 502 can be quickly raised by rotating the first knob 505 in the opposite direction so that the second slide rail 506 is aligned with the first slide rails 4 on both sides to prevent the hanging assembly 6 from falling off;

[0052] After completion, the extension column 604 can be driven to rotate by rotating the toggle rod 6041 as needed, and the rotating disk 602 drives the first wire drum 6021 and the second wire drum 6022 above to rotate synchronously, and the height of the connecting hanging plate 607 is adjusted to connect with the compressor to realize the hoisting operation;

[0053] During maintenance, the first screw rod 504 can be rotated by holding and rotating the first knob 505, and the first screw rod 504 can be threadedly engaged with the first screw hole 503, wherein the first screw rod 504 is rotatably connected to the upper surface of the combination plug block 502, so that the combination plug block 502 can slide and adjust the upper and lower positions inside the combination slot 501, wherein when the combination plug block 502 moves downward, the second slide rail 506 will be staggered with the first slide rails 4 on both sides, and space will be reserved for quickly removing the lifting components 6, so that the present application only needs to rotate the first knob 505 to achieve the rapid removal of several lifting components 6.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A lifting device for compressor maintenance, comprising two support frames (1), characterized in that: A connecting column (2) is fixedly mounted on the upper end of each support frame (1), and a cross bar (3) is fixedly mounted on the upper ends of the connecting columns (2) on both sides. First slide rails (4) are respectively arranged on both sides of the cross bar (3), and a plurality of lifting components (6) for lifting the compressor are slidably mounted inside the first slide rail (4). A quick-release component (5) for quickly disassembling and assembling the lifting components (6) is installed in the middle of the cross bar (3). Support feet (7) are installed at the bottom of the support frames (1) on both sides, and moving components (8) for moving equipment are installed inside the support frames (1) on both sides.

2. A lifting device for compressor maintenance according to claim 1, characterized in that: The quick-release assembly (5) comprises a combination slot (501), wherein the combination slot (501) is arranged in the middle of the crossbar (3), a combination plug-in block (502) is slidably installed inside the combination slot (501), second slide rails (506) are arranged on both sides of the combination plug-in block (502), and the second slide rails (506) are aligned with the first slide rails (4) on both sides.

3. A lifting device for compressor maintenance according to claim 2, characterized in that: A first screw hole (503) is formed through the upper middle part of the cross bar (3); a first screw rod (504) is threadedly installed inside the first screw hole (503); a first knob (505) is fixedly installed at the upper end of the first screw rod (504); and the lower end of the first screw rod (504) is rotatably connected to the upper surface of the combined plug block (502).

4. A lifting device for compressor maintenance according to claim 1, characterized in that: The movable assembly (8) comprises a plurality of movable through holes (801), wherein the movable through holes (801) are opened through the bottom of the support frame (1), a movable seat (802) is arranged inside each of the movable through holes (801), a rotating seat (8021) is arranged at the bottom of each of the movable seats (802), and a movable pulley (8022) is rotatably installed inside each of the rotating seats (8021).

5. A lifting device for compressor maintenance according to claim 4, characterized in that: A connecting rod (803) is commonly installed at the upper end of the movable seat (802) on each side, a limiting seat (804) is fixedly installed in the middle of the connecting rod (803), a movable through hole (801) is opened in the middle of the support frame (1), and the limiting seat (804) is located inside the movable through hole (801).

6. A lifting device for compressor maintenance according to claim 5, characterized in that: A second screw hole (8041) is provided inside the limit seat (804), a second screw rod (805) is rotatably installed inside the movable through hole (801), a second knob (8051) is fixedly installed on the upper side of the second screw rod (805), and the shaft of the second screw rod (805) is threadedly matched with the second screw hole (8041).

7. A lifting device for compressor maintenance according to claim 4, characterized in that: An expansion frame (8024) is fixedly mounted on the outside of each movable seat (802), and an auxiliary pulley (8023) is rotatably mounted inside each expansion frame (8024).

8. The lifting device for compressor maintenance according to claim 1, characterized in that: The hoisting assembly (6) includes an assembly frame (601), a connecting slide (6011) is installed on the upper end of the assembly frame (601), and the connecting slide (6011) is slidably matched with the first slide rail (4). Extension frames (603) are respectively provided on both sides of the assembly frame (601), and support rollers (6032) are rotatably installed inside the extension frames (603) through bearing seats (6031). Lifting ropes (605) are arranged on the outer sides of the support rollers (6032) on both sides, and a falling roller (6061) is movably mounted on the lower end of the lifting rope (605). A placement seat (606) is installed on the outer side of the falling roller (6061), and a connecting hoisting plate (607) is fixedly installed on the bottom of the placement seat (606).

9. A lifting device for compressor maintenance according to claim 8, characterized in that: A rotating disk (602) is rotatably arranged in the middle of the component frame (601), and a first wire drum (6021) and a second wire drum (6022) for reeling in and releasing wires are respectively installed at the upper ends of the rotating disk (602), the wire groove diameter of the first wire drum (6021) is larger than the wire groove diameter of the second wire drum (6022), the interiors of the first wire drum (6021) and the second wire drum (6022) are respectively connected to the two ends of the lifting rope (605), and the winding directions of the lifting rope (605) inside the first wire drum (6021) and the second wire drum (6022) are opposite.

10. A lifting device for compressor maintenance according to claim 9, characterized in that: An extension column (604) is fixedly mounted on the bottom of the rotating disk (602), and a plurality of toggle rods (6041) are fixedly mounted on the outer side of the extension column (604).

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