A screw jack

Abstract

The present invention discloses a screw jack, which relates to the field of screw jacks and includes a bottom box and a lifting plate. Both ends of the top surface of the bottom box are rotatably connected with rotating gears, and a driving mechanism matched with the rotating gears is installed on the top surface of the bottom box. Both ends of the top surface of the bottom box are connected with outer sleeves respectively rotatably connected with each rotating gear. In the present invention, an oil outlet pipe connected to the middle section of the top of the bottom box is connected to the outer sleeve, and an oil inlet pipe connected to both ends of the bottom box is connected to the inner sleeve, so that the lubricating oil inside the outer sleeve and the lubricating oil inside the bottom box form a cycle. During operation, when the screw descends, the lubricating oil with dust adhered to its thread is scraped off by the thread ring and falls between the inner sleeve and the outer sleeve, and enters the bottom box through the oil outlet pipe. At the same time, the clean lubricating oil filtered by the filter screen enters the inner sleeve through the oil inlet pipe to lubricate the screw, preventing dust from increasing the wear of the screw rod, so as to ensure the service life of the screw jack.

Description

Technical Field

[0001] The present invention relates to the field of screw jacks, and specifically to a screw jack. Background Art

[0002] A screw jack, also known as a screw drive mechanism, is mainly used to convert rotational motion into linear motion or vice versa. There are those mainly for transmitting motion, such as the feed screw of a machine tool worktable; and there are also screw drive mechanisms for adjusting the relative positions between parts. Screw jacks are divided into sliding friction mechanisms and rolling friction mechanisms. The sliding screw nut mechanism has a simple structure, is convenient to process, has a low manufacturing cost, and has a self-locking function, but its frictional resistance moment is large and the transmission efficiency is low. Although the ball screw nut mechanism has a complex structure, a high manufacturing cost, and no self-locking function, its great advantages are small frictional resistance moment, high transmission efficiency, high precision, good system stiffness, reversible motion, and long service life.

[0003] A screw jack is composed of a worm reducer and a screw rod. Its reduction component is a worm drive. The worm drives the worm wheel to achieve reduction. The worm wheel is equivalent to the nut of the lifting screw rod and matches with the lifting screw rod. During the working process of the screw jack, the motor drives the worm to drive the worm wheel to rotate, and the thread drives the screw rod to rotate and cooperate with the nut sleeve to drive the lifting plate to rise and fall, and then to lift an object up and down.

[0004] In order to reduce the wear of the screw rod, it is generally necessary to apply grease or lubricating oil on the screw rod to lubricate the screw rod to reduce the friction between the screw rod and the nut sleeve. However, the working scenario of the screw jack is generally dusty, resulting in that when the screw rod extends, the grease or lubricating oil on its surface may adhere to a large amount of dust. When the screw rod retracts, the dust adhered to it will increase the friction with the nut sleeve, making the wear of the screw rod and the nut sleeve more serious, and leading to a rapid reduction in the service life of the screw jack. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a screw jack to solve the technical problem that in the existing screw jack, when the screw rod retracts, the dust adhered to it will increase the friction with the nut sleeve, making the wear of the screw rod and the nut sleeve more serious, and leading to a rapid reduction in the service life of the screw jack.

[0006] To achieve the above object, the present invention provides the following technical solution: A screw lift, comprising a bottom box and a lifting plate. Both ends of the top surface of the bottom box are rotatably connected with rotating gears, and a driving mechanism cooperating with the rotating gears is installed on the top surface of the bottom box. Both ends of the top surface of the bottom box are connected with outer sleeves respectively rotatably connected with each rotating gear, and a threaded ring is arranged at the inner top end of the outer sleeve. Both ends of the bottom surface of the lifting plate are provided with screws cooperating with the threaded ring, and both ends of the top surface of the bottom box are connected with inner sleeves rotatably connected with the rotating gears. The inner sleeve is located inside the outer sleeve and cooperates with the screw. The top surface of the rotating gear is connected with a sliding rod slidably connected with the screw. The bottom end of the inner sleeve is connected with an oil inlet pipe connected to both ends of the bottom box, and the bottom surface of the outer sleeve is connected with an oil outlet pipe connected to the top surface of the bottom box. Both ends inside the bottom box are slidably inserted with filter screens.

[0007] The present invention is further configured as follows: The driving mechanism includes a driving motor, a speed reducer, a worm and a gear set. Both ends of the top surface of the bottom box are respectively rotatably connected with gear sets meshing with the rotating gears, and driving motors are installed at both ends of the top surface of the bottom box. Both ends of the top surface of the bottom box are connected with speed reducers with inputs cooperating with the driving motors, and the output ends of the speed reducers are connected with worms meshing with the gear sets.

[0008] The present invention is further configured as follows: Rack teeth are arranged on both sides of the bottom surface of the lifting plate, and centrifugal locks meshing with the rack teeth are rotatably connected to both sides of the top surface of the bottom box.

[0009] The present invention is further configured as follows: Telescopic cylinders are arranged at the four corners of the top surface of the bottom box, and telescopic rods slidably connected with the telescopic cylinders are arranged at the four corners of the bottom surface of the lifting plate.

[0010] The present invention is further configured as follows: A support sleeve is wrapped around the outer surface of the outer sleeve. Multiple limiting chutes are formed on the outer surface of the screw, and multiple limiting sliders slidably connected with the limiting chutes are arranged on the support sleeve.

[0011] The present invention is further configured as follows: Protrusions are arranged at both ends inside the bottom box, and the surfaces of the protrusions facing each other and the surfaces of the filter screens facing each other are located on the same horizontal plane.

[0012] The present invention is further configured as follows: Slide bars are arranged on the top and bottom surfaces of the filter screen, and slide ways cooperating with the slide bars are formed inside the bottom box.

[0013] The present invention is further configured as follows: Oil pumps are installed on both the oil inlet pipe and the oil outlet pipe.

[0014] In summary, the present invention mainly has the following beneficial effects:

[0015] In the present invention, an oil outlet pipe connected to the middle section of the top of the bottom box is connected to the outer sleeve, and an oil inlet pipe connected to both ends of the bottom box is connected to the inner sleeve, so that the lubricating oil inside the outer sleeve and the lubricating oil inside the bottom box form a circulation. During operation, the screw descends, and the lubricating oil with dust adhering to its thread is scraped off by the thread ring and falls between the inner sleeve and the outer sleeve, then enters the bottom box through the oil outlet pipe. At the same time, the clean lubricating oil filtered by the filter screen enters the inner sleeve through the oil inlet pipe to lubricate the screw, preventing dust from intensifying the wear of the screw rod and ensuring the service life of the screw jack. Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of the second perspective of the present invention;

[0017] Figure 2 is a schematic structural diagram of the first perspective of the present invention;

[0018] Figure 3 is a cross-sectional view of the first perspective of the present invention;

[0019] Figure 4 is a cross-sectional view of the second perspective of the present invention;

[0020] Figure 5 is a schematic structural diagram of the extended state of the present invention;

[0021] Figure 6 For the present invention Figure 2 an enlarged view of A in;

[0022] Figure 7 For the present invention Figure 3 an enlarged view of B in;

[0023] Figure 8 For the present invention Figure 3 an enlarged view of C in;

[0024] Figure 9 For the present invention Figure 3 an enlarged view of D in;

[0025] Figure 10 For the present invention Figure 5 an enlarged view of E in.

[0026] In the figure: 1. Bottom box; 2. Lifting plate; 3. Driving mechanism; 301. Driving motor; 302. Reducing box; 303. Worm; 304. Gear set; 4. Rotating gear; 5. Outer sleeve; 6. Thread ring; 7. Screw; 8. Inner sleeve; 9. Support sleeve; 10. Limiting slider; 11. Limiting chute; 12. Expansion rod; 13. Expansion cylinder; 14. Rack; 15. Centrifugal lock; 16. Oil outlet pipe; 17. Oil inlet pipe; 18. Oil pump; 19. Filter screen; 20. Slide bar. Detailed Embodiments

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0028] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0030] The embodiments of the present invention will be described below according to the overall structure of the present invention.

[0031] A screw jack, as Figures 1 - 10 shown, includes a bottom box 1 and a lifting plate 2. Rotating gears 4 are rotatably connected to both ends of the top surface of the bottom box 1, and driving mechanisms 3 are installed at both ends of the top surface of the bottom box 1 and are respectively engaged with the two rotating gears 4. During operation, the driving mechanism 3 drives the rotating gears 4 to rotate. Sleeve barrels 5 are connected to both ends of the top surface of the bottom box 1 and are respectively rotatably connected to each rotating gear 4. A threaded ring 6 is provided at the top end inside the sleeve barrel 5. Screws 7 that are rotatably connected to the threaded ring 6 are rotatably connected to both ends of the bottom surface of the lifting plate 2. A sliding rod 20 that is slidably connected to the screw 7 is connected to the top surface of the rotating gear 4. The joint surface of the sliding rod 20 is a regular polygon. When the rotating gear 4 rotates, the screw 7 can be driven to rotate through the sliding rod 20. The rotation of the screw 7 in cooperation with the threaded ring 6 can lift and lower, driving the lifting plate 2 to lift and lower.

[0032] At both ends of the top surface of the bottom box 1, inner sleeves 8 rotatably connected to the rotating gears 4 are connected. The inner sleeves 8 are located inside the outer sleeves 5 and cooperate with the screw rods 7. The bottom ends of the inner sleeves 8 are connected to the oil inlet pipes 17 connected to both ends of the bottom box 1. The bottom surface of the outer sleeves 5 is connected to the oil outlet pipes 16 connected to the top surface of the bottom box 1. Oil pumps 18 are installed on both the oil inlet pipes 17 and the oil outlet pipes 16. At both ends inside the bottom box 1, filter nets 19 are slidably inserted. When the screw rods 7 descend, the oil pumps 18 extract the lubricating oil between the inner sleeves 8 and the outer sleeves 5 and enter the bottom box 1 through the oil outlet pipes 16. At the same time, the oil pumps 18 pump the clean lubricating oil filtered by the filter nets 19 inside the bottom box 1 into the inner sleeves 8 through the oil inlet pipes 17. Due to the flow direction of the lubricating oil inside the outer sleeves 5, the dirty lubricating oil scraped off by the screw rods 7 when descending will be driven by the lubricating oil inside the outer sleeves 5 to enter the bottom box 1 through the oil outlet pipes 16 and will not enter the inner sleeves 8 to affect the lubrication of the screw rods 7 by the clean lubricating oil.

[0033] Wherein, sliding strips are provided on both the top surface and the bottom surface of the filter net 19, and sliding grooves matching the sliding strips are formed inside the bottom box 1. The filter net 19 is slidably connected to the bottom box 1 through the sliding strips and the sliding grooves. When the filter net 19 is blocked, the filter net 19 can be taken out for cleaning. Convex platforms are provided at both ends inside the bottom box 1, and the surfaces of the convex platforms close to each other and the surfaces of the filter net 19 close to each other are located on the same horizontal plane, so that a concave pit is formed in the middle inside the bottom box 1, and the outlet of the oil outlet pipe 16 corresponds to this concave pit. Debris in the lubricating oil, such as dust, can precipitate in this concave pit. When the oil inlet pipe 17 extracts the lubricating oil, it is also difficult to drive the debris precipitated in this concave pit, greatly reducing the blocking speed of the filter net 19 and reducing the frequency of taking out the filter net 19 for cleaning.

[0034] To ensure that the lubricating oil will necessarily pass through the filter net 19 for filtration when entering the bottom box 1 from the oil outlet pipe 16 and then entering the inner sleeve 8 through the oil inlet pipe 17, the filter net 19 is located between the connection ports of the oil outlet pipe 16 and the oil inlet pipe 17 with the bottom box 1.

[0035] The specific structure of the driving mechanism 3 is as Figure 1 shown. Driving motors 301 are installed at both ends of the top surface of the bottom box 1, and reduction boxes 302 with input ends connected to the output ends of the two driving motors 301 respectively are connected to both ends of the top surface of the bottom box 1. The output ends of the reduction boxes 302 are both connected with worm gears 303. The driving motors 301 can first drive the worm gears 303 to rotate through the reduction boxes 302 for speed reduction. At both ends of the top surface of the bottom box 1, gear sets 304 meshing with the rotating gears 4 are respectively rotatably connected. The gear sets 304 cooperate with the worm gears 303. When the worm gears 303 rotate, they drive the gear sets 304 to rotate, and then drive the rotating gears 4 meshing with them to rotate. Through double reduction by the reduction boxes 302 and the worm gears 303, a greater torque is provided and heavier objects can be lifted.

[0036] To prevent the lifting plate 2 from falling rapidly due to a failure of the driving mechanism 3, racks 14 are provided on both sides of the bottom surface of the lifting plate 2, and centrifugal locks 15 that mesh with the racks 14 are rotatably connected to both sides of the top surface of the bottom box 1. When the lifting plate 2 is lifted and lowered at a normal speed, the centrifugal locks 15 are driven by the racks 14 to rotate normally. If the falling speed of the lifting plate 2 is too fast, the racks 14 drive the centrifugal locks 15 to descend rapidly, so that the locking structure inside the centrifugal locks 15 is thrown out due to centrifugal force to fix the racks 14, that is, the lifting plate 2.

[0037] If the screw rod 7 extends too long and the lifting plate 2 rises too high, it will cause the overall center of gravity of the device to rise and the contact between the screw rod 7 and the inner sleeve 8 to decrease, both of which will lead to a decrease in the stability of the lifting plate 2. A support sleeve 9 is sleeved on the outer surface of the outer sleeve 5. A plurality of limiting sliding grooves 11 are formed on the outer surface of the screw rod 7, and a plurality of limiting sliding blocks 10 slidably connected to the limiting sliding grooves 11 are arranged on the support sleeve 9. When the screw rod 7 extends until the limiting sliding blocks 10 move to the other end of the limiting sliding grooves 11, the support sleeve 9 will be driven to rise synchronously, and the screw rod 7 is further supported by the support sleeve 9 to enhance the stability of the lifting plate 2.

[0038] At the same time, by connecting telescopic cylinders 13 and telescopic rods 12 that are slidably connected to each other at the four corners of the top surface of the bottom box 1 and the four corners of the bottom surface of the lifting plate 2, the lifting of the lifting plate 2 is made more stable, the lifting plate 2 is prevented from shaking, and the screw rod 7 is prevented from being broken due to the center of gravity of the items placed on the top surface of the lifting plate 2 being skewed.

[0039] During use, the driving motor 301 first drives the worm 303 to rotate through the speed reducer 302 to reduce the speed, and then drives the gear set 304 to rotate to drive the rotating gear 4 meshing with it to rotate. When the rotating gear 4 rotates, the screw rod 7 can be driven to rotate through the sliding rod 20. The rotation of the screw rod 7 cooperates with the threaded ring 6 to lift and lower, driving the lifting plate 2 to lift and lower. When the screw rod 7 descends, the oil pump 18 pumps the lubricating oil between the inner sleeve 8 and the outer sleeve 5 through the oil outlet pipe 16 into the bottom box 1. At the same time, the oil pump 18 pumps the clean lubricating oil filtered by the filter screen 19 in the bottom box 1 into the inner sleeve 8 through the oil inlet pipe 17. Due to the flow direction of the lubricating oil inside the outer sleeve 5, the dirty lubricating oil scraped off by the screw rod 7 when it descends will enter the bottom box 1 through the oil outlet pipe 16 driven by the lubricating oil inside the outer sleeve 5.

[0040] Although the embodiments of the present invention have been shown and described, the specific embodiments are only explanations of the present invention and do not limit the invention. The specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art can, without departing from the principles and purposes of the present invention, make modifications, substitutions and variations that do not contribute creatively to the embodiments as needed, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A screw jack, comprising a bottom box (1) and a lifting plate (2), characterized in that: Both ends of the top surface of the bottom box (1) are rotatably connected with rotating gears (4), and a driving mechanism (3) matched with the rotating gears (4) is installed on the top surface of the bottom box (1). Both ends of the top surface of the bottom box (1) are connected with outer sleeves (5) respectively rotatably connected with each rotating gear (4). A threaded ring (6) is arranged at the top end inside the outer sleeve (5). Screws (7) matched with the threaded ring (6) are arranged at both ends of the bottom surface of the lifting plate (2). Inner sleeves (8) rotatably connected with the rotating gears (4) are connected to both ends of the top surface of the bottom box (1). The inner sleeve (8) is located inside the outer sleeve (5) and is matched with the screw (7). A sliding rod (20) slidably connected with the screw (7) is connected to the top surface of the rotating gear (4). An oil inlet pipe (17) connected to both ends of the bottom box (1) is connected to the bottom end of the inner sleeve (8). An oil outlet pipe (16) connected to the top surface of the bottom box (1) is connected to the bottom surface of the outer sleeve (5). Oil pumps (18) are installed on both the oil inlet pipe (17) and the oil outlet pipe (16). Filter nets (19) are slidably inserted into both ends inside the bottom box (1).

2. The screw jack according to claim 1, characterized in that: The driving mechanism (3) includes a driving motor (301), a reduction box (302), a worm (303) and a gear set (304). Gear sets (304) meshed with the rotating gears (4) are respectively rotatably connected to both ends of the top surface of the bottom box (1). Driving motors (301) are installed at both ends of the top surface of the bottom box (1). Reduction boxes (302) with inputs matched with the driving motors (301) are connected to both ends of the top surface of the bottom box (1). A worm (303) meshed with the gear set (304) is connected to the output end of the reduction box (302).

3. The screw jack according to claim 1, characterized in that: Racks (14) are arranged on both sides of the bottom surface of the lifting plate (2). Centrifugal locks (15) meshed with the racks (14) are rotatably connected to both sides of the top surface of the bottom box (1).

4. The screw jack according to claim 1, characterized in that: Telescopic cylinders (13) are arranged at the four corners of the top surface of the bottom box (1). Telescopic rods (12) slidably connected with the telescopic cylinders (13) are arranged at the four corners of the bottom surface of the lifting plate (2).

5. The screw jack according to claim 1, characterized in that: A support sleeve (9) is sleeved on the outer surface of the outer sleeve (5). A plurality of limiting sliding grooves (11) are formed on the outer surface of the screw (7). A plurality of limiting sliders (10) slidably connected with the limiting sliding grooves (11) are arranged on the support sleeve (9).

6. The screw jack according to claim 1, characterized in that: Protrusions are arranged at both ends inside the bottom box (1). The surfaces of the protrusions close to each other and the surfaces of the filter nets (19) close to each other are located on the same horizontal plane.

7. The screw jack according to claim 1, characterized in that: Sliding strips are arranged on both the top surface and the bottom surface of the filter net (19). Sliding channels matched with the sliding strips are formed inside the bottom box (1).

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