A device for recycling waste lithium batteries

Abstract

The present application relates to the technical field of waste lithium battery recycling, and discloses a waste lithium battery recycling device, which comprises a rack, a secondary crushing box, a primary crushing box and a discharging box arranged in sequence on the surface of the rack, a discharging assembly arranged in the discharging box and used for discharging the lithium battery, the discharging assembly comprising an isolation frame, an extrusion plate and a pushing plate, the isolation frame being installed between the primary crushing box and the discharging box, and a slidingly installed isolation plate in the isolation frame. The discharging assembly is arranged, the needle on the surface of the extrusion plate gradually pierces the shell of the waste lithium battery, the battery is subjected to multi-point drilling, the internal electrolyte of the battery is relieved, the internal pole piece is short-circuited and discharged, the residual capacity of the battery is released, and the safety hazard of subsequent crushing is eliminated. The pushing plate slides along the pushing groove to push the stuck battery, the needle is automatically stripped, manual cleaning is not required, and continuous operation of the equipment is ensured.

Description

Technical Field

[0001] This invention relates to the field of waste lithium battery recycling technology, and in particular to a waste lithium battery recycling and processing device. Background Technology

[0002] With the rapid development of the new energy industry, lithium-ion batteries, with their advantages of high energy density, long cycle life, and environmental friendliness, are widely used in new energy vehicles, energy storage equipment, and digital electronic products. This has led to a large number of discarded lithium batteries. These batteries contain rare metals such as lithium, cobalt, nickel, and manganese, as well as recyclable metals like copper and aluminum, giving them high resource recovery value. However, if discarded lithium batteries are disposed of improperly, their electrolytes can leach toxic and harmful substances such as fluorides and organic pollutants, easily causing soil and water pollution. Furthermore, the residual charge in these batteries can easily trigger spontaneous combustion and explosions, posing significant safety hazards.

[0003] Currently, in the pre-treatment process for recycling waste lithium batteries, crushing and dissociation is the core process, and battery discharge pre-treatment is a key prerequisite for ensuring crushing safety. The traditional brine immersion discharge process is time-consuming and complicated, requiring supporting equipment for material retrieval, drying, and wastewater treatment. It involves high manual labor intensity and low overall operating efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a waste lithium battery recycling and processing device, which solves the problems of the traditional salt water immersion discharge process being time-consuming, complicated, requiring supporting equipment for material retrieval, drying, and wastewater treatment, resulting in high manual labor intensity and low overall operating efficiency.

[0005] To achieve the above objectives, the present invention provides a waste lithium battery recycling and processing device, including a frame. A secondary crushing box, a primary crushing box, and a discharge box are sequentially arranged on the surface of the frame. A discharge assembly is provided in the discharge box for discharging the lithium battery. The discharge assembly includes: An isolation frame is installed between the primary crushing box and the discharge box, and an isolation plate is slidably installed in the isolation frame to isolate the primary crushing box and the discharge box; An extrusion plate is symmetrically slidably installed in the inner cavity of the discharge box, and a piercing needle is fixedly installed on the side of the extrusion plate for piercing and discharging the lithium battery. A pusher plate is slidably installed inside the discharge chamber to detach lithium batteries stuck on the surface of the puncture needle.

[0006] The discharge box is also equipped with a feeding bin for placing used lithium batteries. An electric telescopic rod is fixedly installed on the side of the isolation frame. The telescopic end of the electric telescopic rod is fixedly connected to the isolation plate and is used to drive the isolation plate to move.

[0007] The extrusion plate has a first slider fixedly installed on its side, which is slidably connected to the discharge box. A threaded block is fixedly installed on the other side of the extrusion plate. A bidirectional lead screw is rotatably installed in the inner cavity of the discharge box, and the bidirectional lead screw is threadedly connected to the threaded blocks on both sides. A first motor is fixedly installed on the side of the discharge box, and the output end of the first motor is drivenly connected to the bidirectional lead screw.

[0008] The extrusion plate has a pusher groove on its surface that is compatible with the pusher plate. The pusher plate passes through the pusher groove to detach the lithium battery stuck on the needle surface. Slide rods are symmetrically fixed on the side wall of the pusher plate and are slidably connected to the discharge box.

[0009] A cylinder is fixedly installed on the side of the discharge box, a connecting rod is inserted into the cylinder, a piston is fixedly installed at one end of the connecting rod, and the other end of the connecting rod is fixedly connected to the pusher plate to drive the pusher plate to move.

[0010] The connecting rod is fitted with a first spring, one end of which is fixedly connected to the discharge box and the other end of which is fixedly connected to the piston. The spring is used to push the pusher plate away from the extrusion plate. The isolation frame is also equipped with an elastic airbag, and the elastic airbag is connected to the cylinder by an air pipe.

[0011] The secondary crushing box and the primary crushing box are equipped with crushing components for crushing waste lithium batteries. The crushing components include a first crushing roller and a second crushing roller. The first crushing roller is symmetrically rotated and installed in the primary crushing box. The primary crushing box is also equipped with extrusion teeth to cooperate with the first crushing roller to perform preliminary crushing of waste lithium batteries. The two first crushing rollers are connected by gear transmission, and one of the first crushing rollers is equipped with a first pulley at one end.

[0012] The second crushing roller is symmetrically rotated and installed in the secondary crushing box. The surface of the second crushing roller is provided with crushing blades for secondary crushing of waste lithium batteries. The two second crushing rollers are connected by gear transmission. One of the second crushing rollers is provided with a second pulley at one end. The first pulley and the second pulley are connected by a belt. A second motor is installed on the side of the primary crushing box. The output end of the second motor is connected to the first pulley for transmission.

[0013] The secondary crushing box is also equipped with a screening assembly for screening the crushed waste lithium batteries. The screening assembly includes a screen plate and a cam. The screen plate is slidably disposed under the second crushing roller. A reinforcing plate is fixedly installed at the bottom of the screen plate. A rotating shaft is rotatably installed in the secondary crushing box. The cam is fixedly installed on the surface of the rotating shaft and contacts the surface of the reinforcing plate.

[0014] The secondary crushing box has a sliding groove on its side wall, and a second slider is fixedly installed on the side of the screen plate. The second slider is slidably connected to the sliding groove. A second spring is also fixedly installed in the sliding groove. The other end of the second spring is fixedly connected to the second slider to push the screen plate down. A third pulley is fixedly installed at one end of the rotating shaft, and a belt is connected between the third pulley and the second pulley.

[0015] The advantages and positive effects of the waste lithium battery recycling and processing device of the present invention are as follows: 1. This invention sets up a discharge component, which uses needles on the surface of the extrusion plate to gradually puncture the waste lithium battery casing, drills holes in the battery at multiple points, depressurizes the electrolyte inside the battery, short-circuit discharges the internal electrode plates, releases the residual power of the battery, eliminates the safety hazard of subsequent crushing, and pushes the stuck battery out by the pusher plate sliding along the pusher groove, realizing automatic removal of the needles without manual cleaning and ensuring continuous operation of the equipment.

[0016] 2. This invention sets up a crushing component. The first crushing roller performs primary crushing of waste lithium batteries by squeezing and shearing, breaking the complete battery into large coarse particles, breaking the battery shell and separator, and completing the initial separation. The crushing blades on the surface of the second crushing roller perform fine secondary shearing and tearing of the primary coarse material, peeling the positive electrode black powder from the surface of the copper and aluminum electrode sheets, realizing the full separation of the material and ensuring uniform particle size.

[0017] 3. This invention, through the setting of a screening assembly, uses a second pulley to drive a third pulley to rotate via a belt, which in turn drives a rotating shaft to continuously rotate a cam. During the rotation of the cam, it intermittently pushes against a reinforcing plate, which, in conjunction with the elastic restoring effect of the second spring inside the chute, causes the screen plate to perform high-frequency reciprocating vertical vibration. The material after secondary crushing falls onto the surface of the vibrating screen plate. Material of qualified particle size falls through the screen holes of the screen plate and is collected. Large pieces of incompletely crushed material are thrown upwards and can re-enter the crushing area for secondary crushing, thus achieving material recycling and precise screening. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0019] Figure 1 This is a frontal perspective view provided by an embodiment of the present invention; Figure 2 This is a side perspective view provided by an embodiment of the present invention; Figure 3 This is a front cross-sectional view provided in an embodiment of the present invention; Figure 4 This is a side cross-sectional view provided in an embodiment of the present invention; Figure 5 This is provided by the embodiments of the present invention. Figure 4 Enlarged view at point B in the middle; Figure 6 This is a top sectional view provided in an embodiment of the present invention; Figure 7 This is provided by the embodiments of the present invention. Figure 6 Enlarged view of point A in the middle.

[0020] In the diagram: 1. Frame; 2. Secondary crushing box; 3. Primary crushing box; 4. Discharge box; 5. Feed hopper; 6. Discharge assembly; 601. Isolation frame; 602. Isolation plate; 603. Electric telescopic rod; 604. Extrusion plate; 605. Needle; 606. First slider; 607. Threaded block; 608. Double-acting lead screw; 609. First motor; 610. Pusher chute; 611. Pusher plate; 612. Slide rod; 613. Cylinder; 614. Connecting rod; 615. Piston ; 616, First spring; 617, Elastic airbag; 7, Crushing assembly; 701, First crushing roller; 702, Extrusion teeth; 703, First pulley; 704, Second crushing roller; 705, Crushing blade; 706, Second pulley; 707, Second motor; 8, Screening assembly; 801, Screen plate; 802, Slide groove; 803, Second slider; 804, Second spring; 805, Reinforcing plate; 806, Rotating shaft; 807, Cam; 808, Third pulley. Detailed Implementation

[0021] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0022] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0024] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] Please refer to Figures 1 to 7 This invention provides a waste lithium battery recycling and processing device, including a frame 1. A secondary crushing box 2, a primary crushing box 3, and a discharge box 4 are sequentially arranged on the surface of the frame 1. The surface of the discharge box 4 is also provided with a feeding bin 5 for placing waste lithium batteries. A discharge assembly 6 is provided in the discharge box 4 for discharging the lithium batteries. The discharge assembly 6 includes an isolation frame 601, an extrusion plate 604, and a pusher plate 611. The isolation frame 601 is installed between the primary crushing box 3 and the discharge box 4. An isolation plate 602 is slidably installed in the isolation frame 601 for isolating the primary crushing box 3 and the discharge box 4. An electric telescopic rod 603 is fixedly installed on the side of the isolation frame 601. The telescopic end of the electric telescopic rod 603 is fixedly connected to the isolation plate 602 for driving the isolation plate 602 to move.

[0026] Please refer to Figures 1 to 7 The extrusion plate 604 is symmetrically slidably installed in the inner cavity of the discharge box 4. A piercing needle 605 is fixedly installed on the side of the extrusion plate 604 for piercing and discharging the lithium battery. A first slider 606 is fixedly installed on the side of the extrusion plate 604 and is slidably connected to the discharge box 4. A threaded block 607 is fixedly installed on the other side of the extrusion plate 604. A bidirectional lead screw 608 is rotatably installed in the inner cavity of the discharge box 4 and is threadedly connected to the threaded blocks 607 on both sides. A first motor 609 is fixedly installed on the side of the discharge box 4 and is drivenly connected to the bidirectional lead screw 608.

[0027] Please refer to Figures 1 to 7 The pusher plate 611 is slidably installed in the inner cavity of the discharge box 4 to detach the lithium battery stuck on the surface of the puncture needle 605. The surface of the extrusion plate 604 is provided with a pusher groove 610 adapted to the pusher plate 611. The pusher plate 611 passes through the pusher groove 610 to detach the lithium battery stuck on the surface of the puncture needle 605. The side wall of the pusher plate 611 is symmetrically fixedly installed with a slide rod 612, which is slidably connected to the discharge box 4. The side of the discharge box 4 is fixedly installed with a cylinder 613, and a connecting rod 614 is inserted into the cylinder 613. A piston 615 is fixedly installed at one end of the connecting rod 614, and the other end of the connecting rod 614 is fixedly connected to the pusher plate 611 to drive the pusher plate 611 to move.

[0028] Please refer to Figures 1 to 7 A first spring 616 is sleeved on the surface of the connecting rod 614. One end of the first spring 616 is fixedly connected to the discharge box 4, and the other end of the first spring 616 is fixedly connected to the piston 615. It is used to push the pusher plate 611 away from the extrusion plate 604. An elastic airbag 617 is also provided in the isolation frame 601. An air pipe is connected between the elastic airbag 617 and the cylinder 613.

[0029] Working principle: First, the waste lithium batteries to be processed are fed into the inner cavity of the discharge box 4 through the feeding hopper 5. The first motor 609 is started, which drives the bidirectional lead screw 608 to rotate in the forward direction. The bidirectional lead screw 608 drives the threaded blocks 607 on both sides to move synchronously in opposite directions, so that the two sets of extrusion plates 604 move closer to each other. The piercing needles 605 on the surface of the extrusion plates 604 gradually pierce the waste lithium battery shell, making multi-point drilling of the battery. This achieves depressurization of the electrolyte inside the battery, short-circuit discharge of the internal electrode plates, releases the residual charge of the battery, and eliminates the safety hazards of subsequent crushing. However, some used lithium batteries may become stuck on the surface of the puncture needle 605 due to burrs on the casing and electrolyte adhesion, and cannot be reset and detached with the extrusion plate 604. At this time, the isolation plate 602 in the isolation frame 601 squeezes the elastic airbag 617 during the sliding process. The elastic airbag 617 supplies air to the cylinder 613 through the air pipe, which drives the piston 615 to move the connecting rod 614 forward, thereby pushing the pusher plate 611 to slide along the pusher groove 610, pushing the stuck battery, realizing the automatic removal of the puncture needle 605 without manual cleaning, and ensuring continuous operation of the equipment.

[0030] Please refer to Figures 1 to 7 The secondary crushing box 2 and the primary crushing box 3 are equipped with crushing components 7 for crushing waste lithium batteries. The crushing components 7 include a first crushing roller 701 and a second crushing roller 704. The first crushing roller 701 is symmetrically rotated and installed in the primary crushing box 3. The primary crushing box 3 is also equipped with extrusion teeth 702, which work in conjunction with the first crushing roller 701 to perform preliminary crushing of waste lithium batteries. The two first crushing rollers 701 are connected by gear transmission, and one of the first crushing rollers 701 is equipped with a first pulley 703 at one end.

[0031] Please refer to Figures 1 to 7 The second crushing roller 704 is symmetrically rotated and installed in the secondary crushing box 2. The surface of the second crushing roller 704 is provided with crushing blades 705 for secondary crushing of waste lithium batteries. The two second crushing rollers 704 are connected by gear transmission. One of the second crushing rollers 704 is provided with a second pulley 706 at one end. The first pulley 703 and the second pulley 706 are connected by a belt. The side of the primary crushing box 3 is equipped with a second motor 707. The output end of the second motor 707 is connected to the first pulley 703 for transmission.

[0032] Working principle: The discharged battery material falls into the primary crushing chamber 3. The second motor 707 is started. The second motor 707 drives the two sets of first crushing rollers 701 to rotate synchronously in opposite directions through the first pulley 703. In conjunction with the extrusion teeth 702 on the inner wall of the primary crushing chamber 3, the waste lithium battery is subjected to extrusion and shearing primary crushing, breaking the whole battery into large coarse particles, breaking the battery shell and separator, and completing the initial separation. The first pulley 703 drives the second pulley 706 to rotate synchronously through the belt, which in turn drives the two sets of second crushing rollers 704 to rotate synchronously in opposite directions. The crushing blades 705 on the surface of the second crushing rollers 704 perform fine secondary shearing and tearing of the primary coarse material, peeling the positive electrode black powder from the surface of the copper and aluminum electrode sheets, realizing the full separation of the material and ensuring uniform crushing particle size.

[0033] Please refer to Figures 1 to 7 The secondary crushing box 2 is also equipped with a screening assembly 8 for screening the crushed waste lithium batteries. The screening assembly 8 includes a screen plate 801 and a cam 807. The screen plate 801 is slidably disposed under the second crushing roller 704. A reinforcing plate 805 is fixedly installed at the bottom of the screen plate 801. A rotating shaft 806 is rotatably installed in the secondary crushing box 2. The cam 807 is fixedly installed on the surface of the rotating shaft 806 and contacts the surface of the reinforcing plate 805.

[0034] Please refer to Figures 1 to 7 The secondary crushing box 2 has a sliding groove 802 on its side wall. A second slider 803 is fixedly installed on the side of the screen plate 801. The second slider 803 is slidably connected to the sliding groove 802. A second spring 804 is also fixedly installed in the sliding groove 802. The other end of the second spring 804 is fixedly connected to the second slider 803 and is used to push the screen plate 801 down. A third pulley 808 is fixedly installed on one end of the rotating shaft 806. A belt is connected between the third pulley 808 and the second pulley 706.

[0035] Working principle: The second pulley 706 drives the third pulley 808 to rotate via a belt, which in turn drives the shaft 806 to drive the cam 807 to rotate continuously. During the rotation of the cam 807, it intermittently pushes the reinforcing plate 805. With the elastic restoring effect of the second spring 804 inside the slide groove 802, the screen plate 801 is driven to perform high-frequency reciprocating vertical vibration. The material after secondary crushing falls onto the surface of the vibrating screen plate 801. Material of qualified particle size falls through the screen holes of the screen plate 801 and is collected. Large pieces of incompletely crushed material are thrown upwards and can re-enter the crushing area for secondary crushing, realizing material recycling and precise screening, effectively improving the material crushing quality and resource recovery rate.

[0036] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A waste lithium battery recycling and processing device, comprising a frame (1), wherein a secondary crushing box (2), a primary crushing box (3), and a discharge box (4) are sequentially arranged on the surface of the frame (1), characterized in that, The discharge box (4) is equipped with a discharge assembly (6) for discharging the lithium battery. The discharge assembly (6) includes: An isolation frame (601) is installed between the primary crushing box (3) and the discharge box (4). An isolation plate (602) is slidably installed in the isolation frame (601) for isolating the primary crushing box (3) and the discharge box (4). The extrusion plate (604) is symmetrically slidably installed in the inner cavity of the discharge box (4). A piercing needle (605) is fixedly installed on the side of the extrusion plate (604) for piercing and discharging the lithium battery. Pusher plate (611), which is slidably installed in the inner cavity of the discharge box (4), is used to detach the lithium battery stuck on the surface of the needle (605).

2. The waste lithium battery recycling and processing device as described in claim 1, characterized in that: The surface of the discharge box (4) is also provided with a feeding bin (5) for placing waste lithium batteries. An electric telescopic rod (603) is fixedly installed on the side of the isolation frame (601). The telescopic end of the electric telescopic rod (603) is fixedly connected to the isolation plate (602) for driving the isolation plate (602) to move.

3. The waste lithium battery recycling and processing device as described in claim 1, characterized in that: A first slider (606) is fixedly installed on the side of the extrusion plate (604). The first slider (606) is slidably connected to the discharge box (4). A threaded block (607) is fixedly installed on the other side of the extrusion plate (604). A bidirectional lead screw (608) is rotatably installed in the inner cavity of the discharge box (4). The bidirectional lead screw (608) is threadedly connected to the threaded blocks (607) on both sides. A first motor (609) is fixedly installed on the side of the discharge box (4). The output end of the first motor (609) is connected to the bidirectional lead screw (608) for transmission.

4. The waste lithium battery recycling and processing device as described in claim 1, characterized in that: The surface of the extrusion plate (604) is provided with a pusher groove (610) that is compatible with the pusher plate (611). The pusher plate (611) passes through the pusher groove (610) to detach the lithium battery stuck on the surface of the needle (605). The side wall of the pusher plate (611) is symmetrically fixed with a slide rod (612), and the slide rod (612) is slidably connected to the discharge box (4).

5. The waste lithium battery recycling and processing device as described in claim 4, characterized in that: A cylinder (613) is fixedly installed on the side of the discharge box (4). A connecting rod (614) is inserted into the cylinder (613). A piston (615) is fixedly installed at one end of the connecting rod (614). The other end of the connecting rod (614) is fixedly connected to the pusher plate (611) for driving the pusher plate (611) to move.

6. The waste lithium battery recycling and processing device as described in claim 5, characterized in that: A first spring (616) is sleeved on the surface of the connecting rod (614). One end of the first spring (616) is fixedly connected to the discharge box (4), and the other end of the first spring (616) is fixedly connected to the piston (615). It is used to push the pusher plate (611) away from the extrusion plate (604). An elastic airbag (617) is also provided in the isolation frame (601). An air pipe is connected between the elastic airbag (617) and the cylinder (613).

7. The waste lithium battery recycling and processing device as described in claim 1, characterized in that: The secondary crushing box (2) and the primary crushing box (3) are equipped with crushing components (7) for crushing waste lithium batteries. The crushing components (7) include a first crushing roller (701) and a second crushing roller (704). The first crushing roller (701) is symmetrically rotated and installed in the primary crushing box (3). The primary crushing box (3) is also equipped with extrusion teeth (702) to cooperate with the first crushing roller (701) to perform preliminary crushing of waste lithium batteries. The two first crushing rollers (701) are connected by gear transmission. One of the first crushing rollers (701) is equipped with a first pulley (703) at one end.

8. The waste lithium battery recycling and processing device as described in claim 7, characterized in that: The second crushing roller (704) is symmetrically rotated and installed in the secondary crushing box (2). The surface of the second crushing roller (704) is provided with crushing blades (705) for secondary crushing of waste lithium batteries. The two second crushing rollers (704) are connected by gear transmission. One of the second crushing rollers (704) is provided with a second pulley (706) at one end. The first pulley (703) and the second pulley (706) are connected by a belt. The side of the primary crushing box (3) is equipped with a second motor (707). The output end of the second motor (707) is connected to the first pulley (703) for transmission.

9. The waste lithium battery recycling and processing device as described in claim 8, characterized in that: The secondary crushing box (2) is also equipped with a screening assembly (8) for screening the crushed waste lithium batteries. The screening assembly (8) includes a screen plate (801) and a cam (807). The screen plate (801) is slidably disposed under the second crushing roller (704). A reinforcing plate (805) is fixedly installed at the bottom of the screen plate (801). A rotating shaft (806) is rotatably installed in the secondary crushing box (2). The cam (807) is fixedly installed on the surface of the rotating shaft (806). The cam (807) is in contact with the surface of the reinforcing plate (805).

10. The waste lithium battery recycling and processing device as described in claim 9, characterized in that: The secondary crushing box (2) has a sliding groove (802) on its side wall. A second slider (803) is fixedly installed on the side of the screen plate (801). The second slider (803) is slidably connected to the sliding groove (802). A second spring (804) is also fixedly installed in the sliding groove (802). The other end of the second spring (804) is fixedly connected to the second slider (803) to push the screen plate (801) down. A third pulley (808) is fixedly installed at one end of the rotating shaft (806). A belt is connected between the third pulley (808) and the second pulley (706).

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