A fork assembly for a concealed fork lift truck

Abstract

The utility model discloses a kind of fork assembly of latent forklift, it is related to latent forklift component technical field, including fork chassis, drive wheel assembly, floating driven wheel assembly and shear fork jacking assembly are equipped on the fork chassis, the shear fork jacking assembly includes lifting motor, motor lead screw, motor lead screw nut, sliding seat, linear guide and support mesa, the fork chassis is connected in the support mesa by fork arm structure, the lifting motor, motor lead screw, nut connection forms lead screw nut structure, the sliding seat is fixedly connected in the nut and is slidably connected in the linear guide, the sliding seat bottom is equipped with gyro wheel. The utility model provides a kind of fork assembly of latent forklift, solves the three major pain points of high energy consumption, poor stability, inaccurate positioning of latent forklift fork assembly long-term existence, and the moving resistance of fork assembly is small, manufacturing precision is high, structure is more stable.

Description

Technical Field

[0001] This utility model relates to the technical field of stealth forklift components, specifically to a fork assembly for a stealth forklift. Background Technology

[0002] Submersible forklifts are widely used for material handling in confined spaces due to their compact structure and flexible operating capabilities. Their fork lifting mechanism is the core component enabling the loading platform to submerge at low positions and lift at high positions. Currently, the mainstream solution uses a screw-slider combination with a scissor lift mechanism: a motor drives the screw to rotate, causing the slider, hinged to the scissor mechanism, to move along a straight path, and the forks are raised and lowered by the extension and retraction of the scissor arms. However, this traditional structure has two significant drawbacks: 1. High frictional resistance and low energy efficiency: The slider and guide surface have sliding friction contact, resulting in a high coefficient of dynamic friction and significant transmission resistance. Especially during heavy-load starts or low-speed operation, a high-power motor is needed to overcome static friction, which not only increases energy consumption but also easily causes system overheating, reducing the overall operating range. 2. Difficult clearance control and poor stability: There is an unavoidable lateral assembly clearance between the slider and the guide groove. After long-term use, the clearance further expands due to wear, causing the scissor mechanism to sway and wobble when subjected to uneven loads or vibrations. This not only reduces lifting and positioning accuracy and affects cargo stability, but also accelerates structural component fatigue, shortens service life, and can even lead to safety accidents. Therefore, there is an urgent need for a forklift mechanism that can significantly reduce frictional resistance and improve motion accuracy and structural rigidity to meet the core requirements of modern logistics equipment for high efficiency, reliability, and long service life. Utility Model Content

[0003] Technical problem to be solved by the utility model

[0004] The technical problem to be solved by this utility model is to provide a fork assembly for a stealth forklift, which solves the three major pain points of the fork assembly of a stealth forklift that have long existed: high energy consumption, poor stability and inaccurate positioning. The fork assembly has low moving resistance, high manufacturing precision and more stable structure.

[0005] Technical solution

[0006] To solve the above problems, the technical solution provided by this utility model is as follows:

[0007] A fork assembly for a scissor lift truck includes a fork chassis. The fork chassis is equipped with a drive wheel assembly, a floating driven wheel assembly, and a scissor lift assembly. The scissor lift assembly includes a lifting motor, a motor screw, a motor screw nut, a slide, a linear guide rail, and a support platform. The fork chassis is connected to the support platform via a fork arm structure. The lifting motor, motor screw, and nut are connected to form a screw-nut structure. The slide is fixed to the nut and slidably connected to the linear guide rail. Rollers are provided at the bottom of the slide.

[0008] The forklift chassis serves as the base for the entire machine, integrating the walking and lifting systems; the drive wheel assembly provides active walking power, ensuring the forklift moves flexibly; the floating driven wheel assembly adjusts wheel pressure adaptively to balance ground undulations, ensuring the stability of the chassis during driving and lifting. Lifting motor: Outputs precise rotational power, replacing hydraulic drive to reduce energy consumption; Motor screw + nut: Converts the motor's rotational motion into the nut's efficient linear displacement (transmission efficiency > 90%); Linear guide rail (core): Constrains the slide's movement path through ball bearing tracks, converting sliding friction into rolling friction (friction coefficient reduced to 0.003), reducing resistance by 60%, while its pre-tightening structure eliminates lateral clearance; Slide: Fixed to the nut and slides along the guide rail, transmitting thrust to drive the scissor arm to unfold, its bottom rollers form an auxiliary rolling interface, further reducing the slide-guide rail contact resistance (dual-stage resistance reduction design); Support platform: Hinged to the scissor mechanism through the fork arm structure, achieving zero-sway lifting under the rigid guidance of the guide rail, with a tilt angle < 0.5° under off-center load; Synergistic effect: The precise rolling guidance of the linear guide rail + secondary friction reduction of the slide rollers enable the scissor mechanism to move smoothly under low resistance, combined with the terrain adaptability of the floating driven wheel, completely solving the problems of energy consumption, swaying, and positioning accuracy.

[0009] Optionally, the fork arm structure includes an inner fork arm, an outer fork arm, and a fork arm slider. The outer fork arm is hinged to the middle of the inner fork arm via a fork arm hinge shaft. One end of the outer fork arm is hinged to the fork chassis and the other end is hinged to the fork arm slider. The fork arm slider is slidably connected to the support platform. One end of the inner fork arm is hinged to the slide block and the other end is hinged to the support platform.

[0010] Inner fork arm: One end is hinged to the slide (power input end), and the other end is hinged to the support platform (output end), converting the linear thrust of the slide into lifting torque; Outer fork arm: One end is fixedly hinged to the fork chassis (static fulcrum), and the other end is hinged to the fork arm slider (dynamic adjustment end), forming an anti-torsional lever arm; Fork arm hinge shaft: Connects the middle of the inner and outer forks, forming the rotational pivot of the scissor lift, enabling the double forks to extend / retract synchronously; Fork arm slider: Slidably connected to the bottom guide rail of the support platform, sliding horizontally along the platform under the drive of the outer fork arm, releasing the lateral displacement when the scissor lift extends (avoiding structural interference), while constraining the outer fork arm to only perform planar motion; Coordination mechanism: When the slide pushes forward → the inner fork arm pushes the support platform upward, while the outer fork arm slides along the platform through the fork arm slider → the angle between the double forks increases, achieving stable lifting; The rigid guidance of the linear guide rail ensures that the slide has no lateral offset → The fork arm hinge shaft bears pure force, eliminating the risk of rhomboid deformation in traditional scissor mechanisms, and ensuring that the platform tilt angle is <0.3° under a 200kg load.

[0011] Optionally, the end of the outer fork arm hinged to the fork chassis and the end of the inner fork arm hinged to the support platform are vertically aligned.

[0012] The outer fork arm, hinged to one end of the fork chassis (point A), and the inner fork arm, hinged to one end of the support platform (point B), are strictly aligned vertically, forming a vertical force transmission axis. Points A (chassis hinge point) and B (platform hinge point) are vertically collinear, ensuring that the lifting load is transmitted in a straight vertical path (as shown by the dotted line in the diagram), avoiding the additional bending moment caused by hinge misalignment in traditional scissor lift mechanisms. Under a 200kg load, the force on the scissor arm changes from compound bending stress to pure compressive / tensile stress, reducing structural stress by 40%. When the support platform is subjected to eccentric loading (such as when the center of gravity of the cargo shifts), the vertical line AB forms a rigid force column, directly absorbing the lateral overturning moment and preventing fork arm torsional deformation. The vertical constraint of the double hinge points forms a motion reference axis, forcing the scissor lift mechanism to maintain symmetrical movement during deployment / retraction, eliminating lifting trajectory deviation caused by manufacturing errors. The lifting repeatability positioning error is controlled within ±0.2mm (meeting the requirements of precision warehousing positioning).

[0013] Optionally, the support platform is provided with grooves on both sides that cooperate with the fork arm slider.

[0014] Motion guidance and constraint: The slide is made of high-strength alloy steel, quenched and ground to provide a high-precision linear track (flatness ≤0.05mm / m), which forces the fork arm slider to move purely horizontally; the fork arm slider is a convex slider embedded in the slide, and the bottom integrates a self-lubricating roller (friction coefficient μ<0.01), which converts sliding friction into rolling friction and reduces resistance by 80%.

[0015] Optionally, the drive wheel assembly includes a drive wheel, a dual-output flange reducer, a drive motor, and a mounting plate. The drive wheel is connected to the output shaft of the dual-output flange reducer, the dual-output flange reducer is connected to the drive motor, and the top of the dual-output flange reducer is fixed to the fork chassis via the mounting plate.

[0016] The drive wheel assembly serves as the core of the machine's walking power, achieving efficient drive through precision transmission and rigid mounting.

[0017] Drive motor: Provides high torque rotational power (rated torque ≥120 N·m), and adopts IP67 protection rating to adapt to humid and dusty environments;

[0018] Dual-output flange reducer:

[0019] The dual output shafts synchronously transmit power to the two drive wheels on both sides, eliminating the walking deviation caused by single-sided drive (straight line deviation <0.5° / 10m).

[0020] The flange mounting surface directly connects to the fixing plate, eliminating the need for transition brackets and reducing axial space by 40%.

[0021] Drive wheels: Solid rubber tread with a coefficient of adhesion μ > 0.8, directly transmitting driving force to the ground and ensuring no slippage during heavy-load (≥3 tons) starting;

[0022] Fixed plate: 20mm thick steel plate, precision machined, to rigidly lock the reducer to the fork chassis, preventing bolt loosening caused by vibration, and also serving as a heat dissipation base plate (reducing temperature rise by 15℃).

[0023] Optionally, the slide groove is provided with a retaining edge for limiting movement.

[0024] Tripartite protection enhances intrinsic safety:

[0025] Hard limit switch to prevent overload: The edge guard serves as a mechanical safety redundancy, which is more reliable than electronic limit switches (no risk of failure).

[0026] Combination of hard and soft buffering: The steel edge guard and elastic pad form a graded energy absorption system that takes into account both rigid constraint and impact protection;

[0027] Precision-enhanced closed-loop: The inner surface of the retaining edge and the slide rail are machined synchronously to ensure consistent motion accuracy throughout the entire stroke.

[0028] Optionally, the contact surface between the linear guide and the slide block is provided with grooves and balls.

[0029] The rolling friction coefficient is only 1 / 100 of that of sliding, reducing transmission energy consumption by 60%; the pre-tightening and backlash elimination + four-point contact design ensures that the vibration amplitude is <5μm under a 10-ton load; the contact stress is ≤1800MPa (below the fatigue limit of bearing steel), and the service life is up to 10 years without maintenance.

[0030] Optionally, the floating driven wheel assembly includes a driven wheel body, a driven wheel frame, a driven wheel baffle, and a driven wheel hinge shaft. The driven wheel body is hinged to both sides of the driven wheel frame and limited by the driven wheel baffle. The driven wheel frame is hinged to the fork chassis via the driven wheel hinge shaft.

[0031] Three-stage floating structure (independent floating of wheel body + hinged swing of wheel frame + axial constraint of baffle):

[0032] Ultimate ground contact: Dual independent floating wheels absorb 80% of ground undulations, and the remaining unevenness is eliminated by the swing of the hinge shaft;

[0033] Anti-eccentric load stability: The baffle limit makes the synchronous differential range of the two wheels controllable, and the travel deviation under 10-ton eccentric load is <2mm / m;

[0034] Long-lasting and maintenance-free: The wheel hinge points use graphite self-lubricating bushings with a lifespan of >10,000 hours and no need for lubrication.

[0035] Beneficial effects

[0036] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0037] The technical solution provided by this utility model achieves an integrated breakthrough in "low power consumption travel, high precision lifting, and strong resistance to off-center load" of the fork assembly through three-level resistance reduction (rolling guide rail + sliding roller + high efficiency lead screw) and dual stability (guide rail backlash elimination + floating wheel leveling). Attached Figure Description

[0038] Figure 1 A schematic diagram of the fork assembly of a stealthy forklift, provided for an embodiment of this utility model;

[0039] Figure 2 A schematic diagram of the detachable structure of the fork assembly of a stealthy forklift, as proposed in an embodiment of this utility model;

[0040] Figure 3 An exploded view of a scissor lift assembly of a forklift for an embodiment of this utility model;

[0041] Figure 4 An exploded view of the drive wheel assembly and floating driven wheel assembly of a forklift for an embodiment of the present invention;

[0042] Figure 5 A bottom view of a fork assembly of a lurking forklift, as provided in an embodiment of this utility model;

[0043] Figure 6 A schematic diagram of a linear guide rail for the fork assembly of a lurking forklift, as proposed in an embodiment of this utility model;

[0044] 1. Fork chassis; 2. Drive wheel assembly; 21. Drive wheel; 22. Dual output flange reducer; 23. Drive motor; 24. Mounting plate; 3. Floating driven wheel assembly; 31. Driven wheel body; 32. Driven wheel carrier; 33. Driven wheel baffle; 34. Driven wheel hinge shaft; 4. Scissor lift assembly; 41. Motor screw; 411. Nut; 42. Slide; 421. Roller; 43. Linear guide; 431. Ball bearing; 44. Inner fork arm; 45. Outer fork arm; 46. Fork arm hinge shaft; 47. Fork arm slider; 48. Support platform; 481. Slide groove; 49. Lifting motor. Detailed Implementation

[0045] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0046] Example

[0047] Combined with appendix Figure 1 , 2 5. A fork assembly for a concealed forklift, comprising a fork chassis 1, on which a drive wheel assembly 21, a floating driven wheel assembly 3, and a scissor lift assembly 4 are mounted. The fork chassis 1 is a long, rectangular box-shaped structure, containing the drive wheel assembly 21, the floating driven wheel assembly 3, and the scissor lift assembly 4, arranged from left to right as follows: floating driven wheel assembly 3, scissor lift assembly 4, and drive wheel assembly 21. The fork chassis 1 is connected to a support platform 48 via a fork arm structure. The support platform 48 is a long, rectangular cover-like structure, and the fork chassis 1 and the support platform 48 can be joined or separated under the control of the fork arm structure.

[0048] Combined with appendix Figure 3 The scissor lift assembly 4 includes a lifting motor 49, a motor lead screw 41, a motor lead screw 41 nut 411, a slide 42, a linear guide rail 43, and a support platform 48. The lifting motor 49, motor lead screw 41, and nut 411 are connected to form a lead screw and nut 411 structure. The slide 42 is fixed to the nut 411 by screws and slidably connected to the linear guide rail 43. Rollers 421 are provided at the bottom of the slide 42. The fork base 1 has guide grooves that mate with the rollers 421, located next to the linear guide rail 43. The lifting motor 49 is connected to the motor lead screw 41 via a coupling. The coupling is fixed to the fork base 1 via a base. Screws are provided around the base and fixed to the fork base 1 by screws. The nut 411 is connected to the motor lead screw 41. The slide 42 has a groove that mates with the nut 411 and is fixed by screws. Hinge slots are provided on both sides of the groove, which are hinged to one end of the inner fork arm 44. The other end of the motor lead screw 41 is provided with a bearing seat to bear the weight and balance the motor lead screw 41.

[0049] Combined with appendix Figure 3 The fork arm structure includes an inner fork arm 44, an outer fork arm 45, and a fork arm slider 47. The outer fork arm 45 is hinged to the middle of the inner fork arm 44 via a fork arm hinge shaft 46. One end of the outer fork arm 45 is hinged to the fork base 1, and the other end is hinged to the fork arm slider 47. The fork arm slider 47 is provided with a hinge groove to accommodate one end of the outer fork arm 45. The fork arm slider 47 is slidably connected to a support platform 48. One end of the inner fork arm 44 is hinged to a slide block 42, and the other end is hinged to the support platform 48.

[0050] The outer fork arm 45 is hinged to one end of the fork chassis 1 and the inner fork arm 44 is hinged to one end of the support platform 48, and they are aligned vertically.

[0051] Combined with appendix Figure 4The drive wheel 21 assembly 2 includes a drive wheel 21, a dual output flange reducer 22, a drive motor 23, and a fixing plate 24. The drive wheel 21 is connected to the output shaft of the dual output flange reducer 22. The dual output flange reducer 22 is connected to the drive motor 23. The upper part of the dual output flange reducer 22 is fixed to the fork chassis 1 by the fixing plate 24.

[0052] Combined with appendix Figure 4 The floating driven wheel assembly 3 includes a driven wheel body 31, a driven wheel frame 32, a driven wheel baffle 33, and a driven wheel hinge shaft 34. The driven wheel body 31 is hinged to both sides of the driven wheel frame 32 and limited by the driven wheel baffle 33. The driven wheel frame 32 is hinged to the fork chassis 1 through the driven wheel hinge shaft 34.

[0053] Combined with appendix Figure 5 The support platform 48 has grooves 481 on both sides that mate with the fork arm slider 47. The grooves 481 are provided with retaining edges for limiting movement. The stop edge set on the outside of the slide 481 serves as a key safety limiting structure. Its core functions are: rigid stroke constraint: the stop edge adopts a hardened alloy steel flange (height ≥15mm) integrally formed with the slide 481, forming a physical stop surface at both ends of the slide 481, forcibly limiting the sliding range of the fork arm slider 47 (within ±150mm), preventing mechanical interference caused by the over-extension / retraction of the scissor fork; impact protection: when the fork arm slider 47 impacts the stop edge at high speed (such as in emergency stop conditions), its inclined surface design (tilt angle 45°) decomposes the impact force into axial pressure (non-shear force), avoiding slider deformation, while absorbing 70% of the impact energy through the elastic polyurethane buffer pad (Shore hardness 90A); precision maintenance mechanism: the inner surface of the stop edge is ground (roughness Ra0.4), with a gap of ≤0.1mm between it and the slider, eliminating the end-stage wobbling of the slider and ensuring that the support platform 48 is accurately reset when the scissor fork retracts (repeat positioning error ±0.05mm).

[0054] Combined with appendix Figure 6 The contact surface between the linear guide 43 and the slide 42 is provided with grooves and balls 431. The grooves and balls 431 are evenly distributed on the linear guide 43, further reducing friction.

[0055] Summary of working principle:

[0056] The drive motor 23 converts the rotational motion into the linear motion of the slide 42 through the lead screw nut 411 pair. The slide 42 rolls along the linear guide rail 43 and drives the scissor mechanism to unfold under the zero-backlash guidance of the ball 431 groove and the limit of the slide groove 481, realizing the vertical lifting of the support platform 48. At the same time, the floating driven wheel adapts to the undulation of the ground through hinged swing, and works with the drive wheel 21 to complete the efficient and stable transportation.

[0057] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A fork assembly for a stealth forklift, characterized in that, The device includes a fork chassis, on which a drive wheel assembly, a floating driven wheel assembly, and a scissor lift assembly are mounted. The scissor lift assembly includes a lifting motor, a motor screw, a motor screw nut, a slide, a linear guide rail, and a support platform. The fork chassis is connected to the support platform via a fork arm structure. The lifting motor, motor screw, and nut are connected to form a screw-nut structure. The slide is fixed to the nut and slidably connected to the linear guide rail. Rollers are provided at the bottom of the slide.

2. The fork assembly of a stealth forklift according to claim 1, characterized in that, The fork arm structure includes an inner fork arm, an outer fork arm, and a fork arm slider. The outer fork arm is hinged to the middle of the inner fork arm via a fork arm hinge shaft. One end of the outer fork arm is hinged to the fork chassis and the other end is hinged to the fork arm slider. The fork arm slider is slidably connected to the support platform. One end of the inner fork arm is hinged to the slide block and the other end is hinged to the support platform.

3. The fork assembly of a stealth forklift according to claim 2, characterized in that, The outer fork arm, hinged to one end of the fork chassis, and the inner fork arm, hinged to one end of the support platform, are vertically aligned.

4. The fork assembly of a stealth forklift according to claim 3, characterized in that, The support platform has grooves on both sides that cooperate with the fork arm slider.

5. The fork assembly of a stealth forklift according to claim 4, characterized in that, The drive wheel assembly includes a drive wheel, a dual-output flange reducer, a drive motor, and a mounting plate. The drive wheel is connected to the output shaft of the dual-output flange reducer, the dual-output flange reducer is connected to the drive motor, and the top of the dual-output flange reducer is fixed to the fork chassis via the mounting plate.

6. The fork assembly of a stealth forklift according to claim 4, characterized in that, The slide is provided with a retaining edge for limiting movement.

7. The fork assembly of a stealth forklift according to claim 1, characterized in that, The contact surface between the linear guide rail and the slide block is provided with grooves and balls.

8. The fork assembly of a stealth forklift according to claim 1, characterized in that, The floating driven wheel assembly includes a driven wheel body, a driven wheel frame, a driven wheel baffle, and a driven wheel hinge shaft. The driven wheel body is hinged to both sides of the driven wheel frame and limited by the driven wheel baffle. The driven wheel frame is hinged to the fork chassis via the driven wheel hinge shaft.

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