Engine multi-valve mounting device and using method

Abstract

The invention discloses an engine multi-valve mounting device and a using method. The mounting device comprises a frame, and a pair of sliding ways is fixedly connected to the middle of the frame; a cylinder cover of the engine can be located on the pair of slideways and translated from one side of the frame to the other side of the frame; the positioning tray is positioned between the pair of slideways, and the lower part of the positioning tray is connected with the jacking mechanism; the limiting air cylinder is located on one side of the positioning tray and fixedly connected to the frame. A plurality of conical surface positioning pins are fixedly arranged at the upper end of the positioning tray and correspond to connecting holes preset in the lower end of the cylinder cover; lock clamp mounting holes in one-to-one correspondence with air valves of the cylinder cover are formed in a top plate of the frame; a valve pressure plate seat is arranged under the lock clamp mounting hole, a through hole is formed in the center of the valve pressure plate seat, the valve pressure plate seat is connected to a top limiting plate, and the top limiting plate is connected to the lower side of the top plate. Manual work is replaced by machinery, the multiple air valves of the air cylinder cover simultaneously press the air valve springs and install the lock clamps, the air valve installation efficiency of the air cylinder cover is improved, and manpower is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of engine production, and in particular relates to an engine multi-valve installation device and a use method thereof. Background Art

[0002] The valve mechanism is an important part of the engine's valve train. Its main function is to open and close the intake and exhaust valves according to the engine's working cycle requirements to control the air entering the cylinder combustion chamber and the exhaust gas discharge. The valve mechanism directly affects the engine's combustion performance and power output. The installation reliability of the engine's valves is of great significance to the performance of the entire machine.

[0003] The common engine valve mechanism is composed of valves, valve seats, valve guides, valve springs, valve spring seats and lock clips. The valve mechanism is usually installed by passing the valve through the valve guide and installing it on the valve seat, compressing the valve spring and spring seat to expose the slot on the valve stem and install the lock clip, and finally loosening the valve spring. The tension of the valve spring acts on the lock clip to make it tightly clamped on the valve stem, so that the valve and valve seat are fitted and fixed.

[0004] The invention with application number CN201410276073.3 discloses a valve installation device, which is composed of a valve pressure rod, a valve pressure plate and other structures. The valve pressure plate and the valve pressure rod are connected by a slider, and the pressure rod applies force to the pressure plate to compress the valve spring to facilitate the installation of the lock clamp. The device has a simple structure and is easy to install. It saves time and effort when disassembling and assembling the valve. It can adapt to cylinder heads of different shapes and sizes by adjusting the position of the slider and replacing the pressure plate. However, the device still needs to manually adjust the position of the cylinder head and the pressure rod, which requires a certain amount of manpower, and can only press-fit one valve at a time, so the installation efficiency is low. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the existing defects and provide an engine multi-valve installation device and a method of use, the purpose of which is to use machinery to replace manual labor, to achieve the simultaneous compression of valve springs and installation of locking clips of multiple valves in the cylinder head, and to improve the efficiency of cylinder head valve installation.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an engine multi-valve installation device, comprising a frame, a pair of slideways are fixedly connected in the middle of the frame; the cylinder head of the engine can be seated on the pair of slideways and translated from one side of the frame to the other side; a positioning tray is located between the pair of slideways, and a lifting mechanism is connected to the lower part of the positioning tray, so that the positioning tray can be raised and lowered; a limit cylinder is located on one side of the positioning tray and is fixedly connected to the frame, and its telescopic rod can block the translation of the cylinder head when it is extended; a plurality of conical positioning pins are fixedly arranged on the upper end of the positioning tray, and the conical surface The locating pin corresponds to a preset connecting hole at the lower end of the cylinder head, and is used for inserting the conical locating pin into the connecting hole to fix the position of the cylinder head when the locating tray is lifted; locking clip mounting holes corresponding to the valves of the cylinder head are provided on the top plate of the frame; a valve pressure plate seat is provided directly below the locking clip mounting hole, and a through hole is provided in the center of the valve pressure plate seat, and its periphery is connected to the top limit plate; the top limit plate is connected to the lower side of the top plate, and is used for allowing the valve pressure plate seat to press against the spring of the valve to compress it when the cylinder head is lifted.

[0007] As a further optimization, the jacking mechanism includes a pallet seat connected to the lower end of the positioning pallet, the lower end of the pallet seat is connected to a jacking bracket, the jacking bracket is connected to the telescopic rod of the driving cylinder, and the lower end of the driving cylinder is fixedly connected to the bottom plate of the frame; a sliding sleeve is fixedly connected to the back side of the jacking bracket, the sliding sleeve is mounted on the guide rod, the upper and lower ends of the guide rod are respectively fixedly connected to the vertical plate, and the lower end of the vertical plate is fixedly connected to the bottom plate.

[0008] As a further optimization, the valve pressure plate seat is detachably connected to the top limit plate; the top limit plate is detachably connected to the top plate.

[0009] As a further optimization, the limit cylinder is fixedly connected to the limit cylinder bracket, and the side surface of the limit cylinder bracket is fixedly connected to the frame.

[0010] As a further optimization, it also includes a locking clamp installation mechanism; the locking clamp installation mechanism includes a liftable rubber tube located above the locking clamp installation hole; a core block is fixedly provided at the inner center of the lower end of the rubber tube, and the locking clamp of the engine valve is filled in the gap between the core block and the inner wall of the rubber tube.

[0011] As a further optimization, the locking clamp installation mechanism also includes a lifting cylinder, the telescopic rod of the lifting cylinder is fixedly connected to the top end of the rubber tube, the upper end of the lifting cylinder is fixedly connected to the support frame, and the lower end of the support frame is fixedly connected to the upper end of the top plate of the frame.

[0012] As a further optimization, it also includes an input device and an output device corresponding to the height position of the slide and located on the left and right sides of the frame respectively, which are used to transport the cylinder head into the frame and receive the cylinder head output from the frame respectively.

[0013] The present invention also provides a method for using the engine multi-valve installation device, using the engine multi-valve installation device as described above, comprising the following steps:

[0014] S1: Turn on the control switch of the limit cylinder to extend the telescopic rod of the limit cylinder to the limit position;

[0015] S2: Move the cylinder cover onto the slideway until the telescopic rod of the limit cylinder reaches the limit position;

[0016] S3: Turn on the control switch of the driving cylinder to make the lifting mechanism drive the positioning tray to move upward until the cylinder head is lifted. The lifting mechanism continues to rise until the valve spring seat of the cylinder head presses against the valve pressure plate seat, and the valve stem passes through the through hole of the valve pressure plate seat and leaks out of the lock clip installation position;

[0017] S4: Insert the lock clip through the through hole in the center of the valve plate seat;

[0018] S5: Turn off the control switch of the driving cylinder to make the cylinder cover fall back onto the slideway, and the lifting mechanism and the positioning tray return to their initial positions;

[0019] S6: Turn off the control switch of the limit cylinder and move the cylinder head to the next process.

[0020] As a further optimization, the locking clamp is automatically inserted through a locking clamp installation mechanism; the locking clamp installation mechanism includes a liftable rubber tube located above the locking clamp installation hole; a core block is fixedly provided at the inner center of the lower end of the rubber tube, and the locking clamp of the engine valve is filled in the gap between the core block and the side wall of the rubber tube; after step S3, the rubber tube holding the locking clamp moves downward until it is fitted onto the upper end of the valve stem, and through the elastic deformation of the rubber tube, the locking clamp bypasses the wide part of the upper end of the valve stem until the locking clamp reaches the preset slot on the valve stem; in step S5; as the cylinder head falls, the rubber tube detaches from the upper end of the valve stem, and the rubber tube rises to return to its initial position.

[0021] As a further optimization, the rising and falling of the rubber tube is achieved by a lifting cylinder; the telescopic rod of the lifting cylinder is fixedly connected to the top end of the rubber tube, and its upper end is fixedly connected to the support frame, and the lower end of the support frame is fixedly connected to the upper end of the top plate of the frame.

[0022] Compared with the prior art, the beneficial effects of the present invention are: the present invention uses machinery to replace manual labor, realizes the simultaneous compression of valve springs and installation of locking clips for multiple valves of the cylinder head, improves the cylinder head valve installation efficiency, and saves manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention;

[0024] Figure 2 It is a schematic diagram of the partial structure of the locking clip installation location in Example 1 of the present invention;

[0025] Figure 3 It is a structural schematic diagram of the jacking mechanism of Example 1 of the present invention;

[0026] Figure 4 It is a schematic diagram of the local structure of the locking clip installation location of Example 2 of the present invention.

[0027] In the figure: 1. frame; 11. locking clamp mounting hole; 12. rubber tube; 13. core block; 14. telescopic rod of lifting cylinder; 2. top limit plate; 3. valve pressure plate seat; 4. limit cylinder bracket; 5. limit cylinder; 6. slideway; 7. lifting mechanism; 71. lifting bracket; 72. tray seat; 73. guide rod; 8. positioning tray; 81. conical positioning pin; 9. driving cylinder; 100. locking clamp; 200. valve stem. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Example 1, please refer to Figure 1-3 .

[0030] The present invention provides a technical solution: The present invention provides a technical solution: A multi-valve installation device for an engine, comprising a steel frame 1, a top limit plate 2, a valve pressure plate seat 3, a limit cylinder bracket 4, a limit cylinder 5, a slideway 6, a lifting mechanism 7 (including a lifting bracket 71, a tray seat 72 and a guide rod 73), a positioning tray 8, a driving cylinder 9 and a cylinder control switch.

[0031] It is characterized in that: the metal frame 1 is positioned and fixed between two sections of roller conveyors or conveyor belts by four legs, the metal frame 1 includes three layers of plates, the upper, middle and lower layers, the upper and middle layers are hollow in the middle, and the top limit plate of the cylinder head and the positioning tray 8 are respectively installed, the lower layer is used to place the lifting mechanism 7 driving cylinder 9, and a vertical plate perpendicular to the lower layer is welded to fix the guide rod 73; the top limit plate 2 is fixed to the bottom of the upper layer of the metal frame 1 by bolts and locking nuts; the valve pressure plate seat 3 is installed on the valve groove of the top limit plate 2 for positioning, and the screws are passed through the top limit plate 2 and screwed to the mounting threads of the valve pressure plate seat 3; the limit cylinder bracket 4 is fixed to the side of the middle plate of the metal frame 1 close to the cylinder head after installation and removal, and the bracket height is lower than the slide 6 height; the limit cylinder 5 is fixed to the bottom of the limit cylinder bracket 4 by screws to ensure that the extended position of the telescopic rod can just block the cylinder head from moving forward to ensure that the cylinder head is fixed in a suitable position; the slide 6 is fixed to the metal by positioning threaded pins The middle plate of the metal frame 1 is perpendicular to both sides of the forward direction to ensure that the slide is aligned with the front and rear rollers or conveyor belts; the lifting bracket 71 includes a top plate, side plates and rib plates. The guide nylon slider is fixed on the side plate with bolts, and the positioning is maintained by the groove on the bottom of the top plate and the dome plate of the driving cylinder 9; the bottom of the tray seat 72 is fixed to the top plate of the lifting bracket 71 with screws; the guide rod 73 is fixed to the lower vertical plate of the metal frame 1 through the upper and lower pipe clamps to ensure that the guide rod is vertical to the horizontal plane; the positioning tray 8 is fixed to the top of the tray seat 72 by screws, and the upper plane of the positioning tray 8 is processed with a process hole consistent with the center position of the cylinder head valve, and a conical positioning pin is installed at the corresponding cylinder head fixing hole position. When the driving cylinder 9 is not working, the positioning tray 8 and its positioning pin must be lower than the upper plane of the slide 6 to avoid interference with the cylinder head; the driving cylinder 9 is fixed to the bottom plate of the metal frame by screws and the cylinder bottom plate, and then the fixing screws are passed through the waist-shaped holes of the bottom plate to fix the driving cylinder 9 to the lower plate of the metal frame. Figure 1

[0032] To ensure that the valve spring seat of the cylinder head can be aligned and pressed against the valve pressure plate seat 3 when the assembled engine multi-valve installation device is working, the mounting holes of the top limit plate 2 and the bottom plate of the driving cylinder 9 are both waist-shaped holes, which are convenient for adjusting the valve position alignment of the top limit plate 2 and the positioning tray 8. The process holes on the positioning tray 8 are used to check the alignment effect.

[0033] The lifting mechanism 7 is constrained in horizontal position and vertical movement direction by the top plate of the driving cylinder 9 and the guide rod 73. The lifting mechanism 7 is made into a separate structure for easy assembly and adjustment according to the actual matching size. Figure 3

[0034] The lifting mechanism 7 and the positioning tray 8 together complete the rising movement of the cylinder head, and the top limit plate 2 and the valve pressure plate seat 3 together complete the press-fitting positioning of the cylinder head valve spring seat. Figure 2The two are made into separate components to achieve the purpose of replacing a small number of parts to adapt to different cylinder heads, which can reduce costs and improve versatility.

[0035] The telescopic rod of the limiting cylinder 5 basically limits the forward position of the cylinder head, and the positioning pin of the positioning tray 8 accurately positions the cylinder head in the horizontal direction. The positioning pin on the positioning tray 8 has a cone above and a cylindrical structure below. When the positioning tray 8 is rising, the cone structure is first inserted into the cylinder head fixed installation hole. Under the action of gravity, the cylinder head adjusts its position slightly along the cone structure until the cylinder head fixed installation hole is fully inserted into the positioning pin cylinder to achieve complete positioning.

[0036] When performing the cylinder head valve press-fitting operation, the specific installation process is described as follows:

[0037] S1: Turn on the control switch of the limit cylinder 5 to extend the telescopic rod of the limit cylinder 5 to the limit position;

[0038] S2: Move the cylinder cover onto the slideway 6 until the telescopic rod of the limit cylinder 5 is limited;

[0039] S3: Turn on the control switch of the driving cylinder 9 to make the lifting mechanism 7 drive the positioning tray 8 to move upward until the cylinder head is lifted, and the lifting mechanism 7 continues to rise until the cylinder head valve spring seat is pressed tightly on the valve pressure plate seat 3, and the valve stem 200 passes through the valve pressure plate seat 3 and leaks out of the installation position of the locking clip 100;

[0040] S4: insert the locking clip 100 of each valve through the central through hole of the valve pressure plate seat 3;

[0041] S5: Turn off the control switch of the driving cylinder 9 to make the cylinder cover fall back onto the slideway 6, and the lifting mechanism 7 and the positioning tray 8 return to the initial position;

[0042] S6: Turn off the control switch of the limit cylinder 5 and move the cylinder head to the next process.

[0043] The advantages of this embodiment are as follows.

[0044] (1) The stable mechanical structure can be used to automatically adjust the spatial position of the cylinder head in a small range, which basically does not require manual intervention and adjustment, thus reducing the difficulty of operation and improving installation reliability.

[0045] (2) By lifting the cylinder head to the top limit plate 2, the valve springs of the multiple valves of the cylinder head are simultaneously compressed, and the locking clip 100 is inserted to achieve simultaneous installation and fixation of the multiple valves of the cylinder head, which greatly improves the installation efficiency.

[0046] (3) By replacing the top limit plate 2 or the valve pressure plate seat 3, cylinder heads with different valve structures and sizes can be adapted; by replacing the positioning tray 8, the positioning of cylinder heads with different structural sizes can be met; and by adjusting the distance between the slideways 6, cylinder heads with different external sizes can be accommodated.

[0047] (4) Through the cylinder control switch, on the one hand, the limit cylinder 5 is controlled to work so as to stop the cylinder head at the work station and release it after installation; on the other hand, the lifting mechanism 7 is controlled to drive the cylinder 9 to work so as to lift the cylinder head and complete the tightening and loosening of all valve springs. The cylinder work replaces the manual work, which is simple and efficient to operate, ensures the work quality, increases the work efficiency, and has high practical value.

[0048] In summary, this embodiment uses machinery to replace manual labor to achieve simultaneous compression of valve springs of multiple valves of the cylinder head and installation of the locking clip 100, thereby improving the efficiency of cylinder head valve installation and saving manpower.

[0049] Example 2, please refer to Figure 1-4 .

[0050] The difference between this embodiment and embodiment 1 is that the locking clip 100 is automatically inserted through a locking clip installation mechanism; the locking clip installation mechanism includes a rubber tube 12 that can be raised and lowered and is located above the locking clip installation hole 11; a core block 13 is fixedly provided at the inner center of the lower end of the rubber tube 12, and the locking clip 100 of the engine valve is filled in the gap between the core block 13 and the side wall of the rubber tube 12; after step S3, the rubber tube 12 clamping the locking clip 100 moves downward until it is fitted onto the upper end of the valve stem 200, and through the elastic deformation of the rubber tube 12, the locking clip 100 bypasses the wide part of the upper end of the valve stem until the locking clip 100 reaches the preset slot on the valve stem 200; in step S5; as the cylinder head falls, the rubber tube 12 detaches from the upper end of the valve stem 200, and the rubber tube 12 rises to restore its initial position.

[0051] A more preferred embodiment is that the rising and falling of the rubber tube 12 is achieved by a lifting cylinder; the telescopic rod 14 of the lifting cylinder is fixedly connected to the top end of the rubber tube 12, and its upper end is fixedly connected to the support frame, and the lower end of the support frame is fixedly connected to the upper end of the top plate of the frame 1.

[0052] After expansion, the installation device of this embodiment is upgraded to a fully automated device. The slideway 6 is replaced with an automated conveyor belt, and a position sensor is used to receive the forward and upward position signals of the cylinder head, and the two cylinders are automatically controlled by writing a program into the PLC, and a locking clamp installation mechanism is used.

[0053] In this way, after the cylinder head is transferred to the right place, the lifting mechanism 7 drives the cylinder 9 to automatically lift the cylinder head. After the cylinder head rises to a certain height, the valve spring is compressed, the lock clamp installation mechanism starts to put in the lock clamp 100, and then the lifting mechanism 7 drives the cylinder 9 to fall back, the limit cylinder 5 starts to work to control the telescopic rod to descend, and the cylinder head is released normally. It can be applied to standard automated assembly line production.

[0054] It can be seen that this embodiment has a higher degree of automation than embodiment 1, no human intervention is required, and fully automated installation is achieved with higher efficiency.

[0055] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An engine multi-valve mounting device, comprising a frame (1), characterized in that: A pair of slideways (6) is fixedly connected in the middle of the frame (1); the cylinder head of the engine can be seated on the pair of slideways (6) and can be translated from one side of the frame (1) to the other side; a positioning tray (8) is located between the pair of slideways (6), and its lower part is connected to a lifting mechanism (7) for lifting the positioning tray (8); The limiting cylinder (5) is located on one side of the positioning tray (8) and is fixedly connected to the frame (1). When the telescopic rod is extended, it can block the cylinder cover from translating. A plurality of conical positioning pins (81) are fixedly arranged at the upper end of the positioning tray (8), and the conical positioning pins (81) correspond to connection holes preset at the lower end of the cylinder head, so that when the positioning tray (8) is lifted, the conical positioning pins (81) are inserted into the connection holes to fix the position of the cylinder head; A locking clamp mounting hole (11) corresponding to the valve of the cylinder head is provided on the top plate of the frame (1); a valve pressure plate seat (3) is provided directly below the locking clamp mounting hole (11); a through hole is provided at the center of the valve pressure plate seat (3), which is connected to the top limit plate (2); the top limit plate (2) is connected to the lower side of the top plate, so that when the cylinder head is lifted, the valve pressure plate seat (3) can be pressed against the spring of the valve to compress it.

2. An engine multi-valve installation device according to claim 1, characterized in that: The lifting mechanism (7) comprises a tray seat (72) connected to the lower end of the positioning tray (8), the lower end of the tray seat (72) is connected to a lifting bracket (71), the lifting bracket (71) is connected to the telescopic rod of the driving cylinder (9), and the lower end of the driving cylinder (9) is fixedly connected to the bottom plate of the frame (1); the back side of the lifting bracket (71) is fixedly connected with a sliding sleeve (74), the sliding sleeve (74) is sleeved on the guide rod (73), the upper and lower ends of the guide rod (73) are respectively fixedly connected to the vertical plate (75), and the lower end of the vertical plate (75) is fixedly connected to the bottom plate.

3. The engine multi-valve installation device according to claim 1, characterized in that: The valve pressure plate seat (3) is detachably connected to the top limit plate (2); the top limit plate (2) is detachably connected to the top plate.

4. The engine multi-valve installation device according to claim 1, characterized in that: The limiting cylinder (5) is fixedly connected to the limiting cylinder bracket (4), and the side surface of the limiting cylinder bracket (4) is fixedly connected to the frame (1).

5. The engine multi-valve installation device according to claim 1, characterized in that: The invention also comprises a locking clamp installation mechanism; the locking clamp installation mechanism comprises a rubber tube (12) which is liftable and located above the locking clamp installation hole (11); a core block (13) is fixedly arranged at the inner center of the lower end of the rubber tube (12); the locking clamp (100) of the engine valve is filled in the gap between the core block (13) and the inner wall of the rubber tube (12).

6. An engine multi-valve installation device according to claim 5, characterized in that: The locking clamp installation mechanism also includes a lifting cylinder, the telescopic rod (14) of the lifting cylinder is fixedly connected to the top end of the rubber tube (12), the upper end of the lifting cylinder is fixedly connected to the support frame, and the lower end of the support frame is fixedly connected to the upper end of the top plate of the frame (1).

7. The engine multi-valve installation device according to claim 1, characterized in that: It also includes an input device and an output device corresponding to the height position of the slideway (6) and located on the left and right sides of the frame (1), respectively, for transporting the cylinder head into the frame (1) and receiving the cylinder head output from the frame (1).

8. A method for using an engine multi-valve installation device, characterized in that: The engine multi-valve installation device according to any one of claims 1 to 7 comprises the following steps: S1: Turn on the control switch of the limit cylinder (5) so that the telescopic rod of the limit cylinder (5) extends to the limit position; S2: Move the cylinder cover onto the slideway (6) until the telescopic rod of the limit cylinder (5) reaches the limit position; S3: Turn on the control switch of the driving cylinder (9) to enable the lifting mechanism (7) to drive the positioning tray (8) to move upward until the cylinder head is lifted, and the lifting mechanism (7) continues to rise until the cylinder head valve spring seat presses against the valve pressure plate seat (3), and the valve stem (200) passes through the through hole of the valve pressure plate seat (3) and leaks out of the installation position of the locking clip (100); S4: insert the locking clip (100) through the through hole in the center of the valve plate seat (3); S5: Turn off the control switch of the driving cylinder (9) to make the cylinder cover fall back onto the slideway (6), and the lifting mechanism (7) and the positioning tray (8) return to their initial positions; S6: Turn off the control switch of the limit cylinder (5) and move the cylinder head to the next process.

9. An engine multi-valve installation device according to claim 8, characterized in that: In the step S4, the locking clamp (100) is automatically inserted by a locking clamp installation mechanism; the locking clamp installation mechanism comprises a rubber tube (12) which is liftable and located above the locking clamp installation hole (11); a core block (13) is fixedly arranged at the inner center of the lower end of the rubber tube (12), and the locking clamp (100) of the engine valve is filled in the gap between the core block (13) and the side wall of the rubber tube (12); After step S3, the rubber tube (12) holding the locking clip (100) moves downward until it is fitted onto the upper end of the valve stem (200), and the locking clip (100) is caused to bypass the wide portion of the upper end of the valve stem (200) through elastic deformation of the rubber tube (12) until the locking clip (100) reaches a preset slot on the valve stem (200); In step S5, as the cylinder head falls, the rubber tube (12) is separated from the upper end of the valve stem (200), and the rubber tube (12) rises to restore the initial position.

10. An engine multi-valve installation device according to claim 9, characterized in that: The rise and fall of the rubber tube (12) are achieved by a lifting cylinder; the telescopic rod (14) of the lifting cylinder is fixedly connected to the top end of the rubber tube (12), and its upper end is fixedly connected to a support frame, and the lower end of the support frame is fixedly connected to the upper end of the top plate of the frame (1).

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