CN117658021A - Telescopic fork and stacker - Google Patents

Abstract

Embodiments of the present disclosure disclose a telescoping fork and stacker. One embodiment of the telescopic fork comprises: the first single fork mechanism and the second single fork mechanism are used for bearing goods; the first single-fork mechanism and the second single-fork mechanism comprise fixed fork arms, middle fork arms and transmission components, and the fixed fork arms are positioned between the middle fork arms and the transmission components; the driving mechanism is connected with the transmission assembly of the first single-fork mechanism, and the transmission assembly of the first single-fork mechanism is connected with the transmission assembly of the second single-fork mechanism; the middle fork arm is provided with a rack on the end face facing the fixed fork arm, and the rack extends along the length direction of the middle fork arm; the transmission assembly comprises a transmission gear and is fixed on the fixed fork arm; the fixed fork arm is provided with a matching through hole, and the transmission gear is meshed with the rack on the middle fork arm through the matching through hole. This embodiment relates to warehouse logistics technology and realizes the telescopic movement of fork through gear drive structure. The device can be more compact in structure, and transmission noise can be reduced.

Description

Telescopic fork and stacker

Technical Field

The embodiment of the disclosure relates to the technical field of warehouse logistics, in particular to a telescopic fork and a stacker.

Background

Modern logistics develop rapidly and warehouse automation is increasing. Pallets are often the usual carriers for goods in a warehouse area. When pallet goods are taken and transported, telescopic pallet forks are generally used. The telescopic fork is widely applied, and can be applied to various carriers, such as an automatic guide vehicle, a stacker and the like, and the telescopic fork can be configured for carrying out pallet cargo transportation.

However, the inventors have found that the telescopic movement of the forks is generally achieved using a sprocket and chain drive. The parts of the chain drive will generally be relatively bulky, which increases the overall structural volume of the device. And the noise of the chain drive will be greater.

The above information disclosed in this background section is only for enhancement of understanding of the background of the inventive concept and, therefore, may contain information that does not form the prior art that is already known to those of ordinary skill in the art in this country.

Disclosure of Invention

The disclosure is in part intended to introduce concepts in a simplified form that are further described below in the detailed description. The disclosure is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Some embodiments of the present disclosure propose a telescoping fork and stacker to address one or more of the technical problems mentioned in the background section above.

In a first aspect, some embodiments of the present disclosure provide a telescopic pallet fork comprising: the first single fork mechanism and the second single fork mechanism are used for bearing goods; the first single-fork mechanism and the second single-fork mechanism comprise fixed fork arms, middle fork arms and transmission components, and the fixed fork arms are positioned between the middle fork arms and the transmission components; the driving mechanism is connected with the transmission assembly of the first single-fork mechanism, and the transmission assembly of the first single-fork mechanism is connected with the transmission assembly of the second single-fork mechanism; the middle fork arm is provided with a rack on the end face facing the fixed fork arm, and the rack extends along the length direction of the middle fork arm; the transmission assembly comprises a transmission gear and is fixed on the fixed fork arm; the fixed fork arm is provided with a matching through hole, and the transmission gear is meshed with the rack on the middle fork arm through the matching through hole, so that the telescopic movement of the middle fork arm is realized under the action of the driving mechanism.

In some embodiments, the middle fork arm is provided with first guide grooves on two sides of the rack on the end surface facing the fixed fork arm; the fixed fork arm is provided with a plurality of supporting parts matched with the first guide grooves, and the supporting parts are arranged at intervals along the length direction of the fixed fork arm.

In some embodiments, the plurality of supporting members include a plurality of rollers and a plurality of supporting blocks, the plurality of rollers are symmetrically arranged at two sides of the fixed fork arm, the plurality of supporting blocks are symmetrically arranged at two sides of the fixed fork arm, and the rollers and the supporting blocks at the same side are alternately arranged at intervals.

In some embodiments, the rotational axis of the roller is parallel misaligned with the mounting axis, and the diameter of the roller is greater than the height of the support block.

In some embodiments, the middle yoke is located at the upper end of the fixed yoke and the drive assembly is located at the lower end of the fixed yoke; wherein the upper end and the lower end are opposite ends, and the lower end is one end facing the ground.

In some embodiments, the first and second single-prong mechanisms further include an upper prong, the middle prong being located between the fixed prong and the upper prong.

In some embodiments, a groove is formed on the end surface of the upper fork arm facing the middle fork arm and is used for accommodating the middle fork arm, and a plurality of supporting parts are arranged on two inner side walls of the groove and are arranged at intervals along the length direction of the upper fork arm; second guide grooves are formed on two side surfaces of the middle fork arm and are matched with the supporting parts in the grooves.

In some embodiments, traction components and guide rollers are arranged on two sides of the middle fork arm, and the guide rollers are arranged at positions, close to two ends, of the middle fork arm; the two sides of the fixed fork arm are provided with adjusting parts at positions close to the first end, and the adjusting parts are used for adjusting the tension of the traction part; one end of the traction component is connected with the first end of the upper fork arm, and the other end bypasses the guide roller at the second end of the middle fork arm and is connected with the adjusting component; the first end and the second end are opposite ends in the length direction, and the second end is one end extending out when the fork stretches out and draws back.

In some embodiments, a detecting component is further installed on the telescopic fork and is used for detecting whether the upper fork arm is retracted and reset; the detection assembly comprises a proximity switch and a sensing plate, wherein the proximity switch is installed on one side face of the fixed fork arm, and the sensing plate is installed on the same side face of the upper fork arm.

In some embodiments, the drive assembly includes a plurality of drive gears aligned along the length of the stationary yoke; the transmission assembly further comprises a transmission box which is fixed on the fixed fork arm, and a gear in the transmission box is meshed with one transmission gear in the plurality of transmission gears; the transmission case in the first single-fork mechanism is connected with the transmission case in the second single-fork mechanism through a universal coupling.

In some embodiments, the drive mechanism includes a drive motor and a drive gear mounted on a shaft of the drive motor; the transmission case in the first single-fork mechanism is provided with a driven gear on the outer end surface on the same side as the driving gear, and the driven gear is connected with the driving gear through a transmission part; the driven gear is arranged on a rotating shaft of the transmission case through a torque limiter, and each gear adopts a positive displacement gear.

In a second aspect, some embodiments of the present disclosure provide a stacker comprising: an apparatus main body; a telescopic fork, which adopts the structure of the telescopic fork described in any implementation manner of the first aspect; and the moving mechanism is arranged on the equipment main body and used for driving the telescopic fork to do lifting motion along the equipment main body.

The above embodiments of the present disclosure have the following advantageous effects: the telescopic fork of some embodiments of the present disclosure may promote compactness of the device structure, and also help reduce noise generated during telescopic power transmission. In particular, the parts of the chain drive are typically relatively large in size, with the same power being transmitted, or the equipment being moved the same distance, which increases the overall structural volume of the equipment. And the noise of the chain drive will be greater. Based on this, the telescoping prongs of some embodiments of the present disclosure may be engaged with the drive gear of the drive assembly by forming a rack on the end of the middle prong that faces the fixed prong. And then the power generated by the driving mechanism is transmitted to the middle fork arm in a gear transmission mode, so that the telescopic movement of the middle fork arm is realized. The gearing helps to increase the compactness of the device, so that the overall volume of the device can be reduced. In addition, the noise generated will be relatively small compared to a chain drive, contributing to a reduction in ambient noise.

Drawings

The above and other features, advantages, and aspects of embodiments of the present disclosure will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. The same or similar reference numbers will be used throughout the drawings to refer to the same or like elements. It should be understood that the figures are schematic and that elements and components are not necessarily drawn to scale.

FIG. 1 is a schematic top view of some embodiments of the telescoping forks of the present disclosure;

FIG. 2 is a schematic bottom view of some embodiments of the telescoping forks of the present disclosure;

FIG. 3A is a schematic view of the first single-fork mechanism in a contracted state;

FIG. 3B is a schematic view of the first single-fork mechanism in an extended state;

FIG. 3C is a schematic diagram of an exploded construction of the first single-fork mechanism;

FIG. 3D is a schematic cross-sectional structural view of the first single-fork mechanism;

FIG. 4A is a right side structural schematic view of some embodiments of a middle yoke;

FIG. 4B is a schematic cross-sectional view of the middle yoke shown in FIG. 4A at B-B';

FIG. 5 is a schematic view of some embodiments with one side hidden by the fixed yoke;

FIG. 6A is a schematic diagram of some embodiments of a transmission case;

FIG. 6B is an exploded view of the transmission case of FIG. 6A;

FIG. 6C is a schematic diagram of other embodiments of a transmission case;

FIG. 6D is an exploded view of the transmission case of FIG. 6C;

fig. 7 is an enlarged schematic view of the telescopic fork at a shown in fig. 2.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It should be understood that the drawings and embodiments of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings. Embodiments of the present disclosure and features of embodiments may be combined with each other without conflict.

It should be noted that the terms "first," "second," and the like in this disclosure are merely used to distinguish between different devices, modules, or units and are not used to define an order or interdependence of functions performed by the devices, modules, or units.

It should be noted that references to "one", "a plurality" and "a plurality" in this disclosure are intended to be illustrative rather than limiting, and those of ordinary skill in the art will appreciate that "one or more" is intended to be understood as "one or more" unless the context clearly indicates otherwise.

The names of messages or information interacted between the various devices in the embodiments of the present disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Fig. 1 illustrates a schematic structural view of some embodiments of the telescopic forks of the present disclosure. As shown in fig. 1, the telescopic fork may comprise a first single fork mechanism 1, a second single fork mechanism 2 and a drive mechanism 3. Here, the first single fork mechanism 1 and the second single fork mechanism 2 can be used for carrying goods. The first single-fork mechanism 1 and the second single-fork mechanism 2 may each comprise a fixed yoke, a middle yoke and a transmission assembly. As shown in fig. 3A, the first single-fork mechanism 1 may include a fixed yoke 11, a middle yoke 12, and a drive assembly 13.

Here, the fixed yoke 11 may be located between the middle yoke 12 and the transmission assembly 13. As shown in fig. 3D, the middle yoke 12 may be formed with a rack C at an end surface facing the fixed yoke 12. The rack C extends along the length of the middle yoke. Meanwhile, as shown in fig. 2, the transmission assembly 13 may include a transmission gear 131. The transmission gear 131 may be fixed to the fixed yoke 11. In addition, as shown in fig. 3D and 5, the fixed yoke 11 may be formed with a fitting through hole at a position corresponding to the transmission gear 131. At this time, the transmission gear 131 can be engaged with the rack C on the middle yoke 12 through the fitting through hole.

In some embodiments, as shown in fig. 1 and 2, the drive mechanism 3 may be coupled to a transmission assembly 13 of the first single fork mechanism 1. And the transmission assembly 13 of the first single-fork mechanism 1 is connected with the transmission assembly 23 of the second single-fork mechanism 2. In this way, under the action of the driving mechanism 3, the telescopic movement of the middle fork arm can be realized through the gear transmission of the transmission gear and the rack.

Compared with a chain transmission mode, the gear transmission mode has more compact structure under the condition of transmitting the same force. In this way, it is helpful to reduce the overall structural size of the fork. At the same time, the gear drive is typically relatively less noisy than the chain drive, helping to reduce the environmental noise. In addition, during the transmission, the chain is easily elongated and worn, causing its pitch to become large. And then the dislocation condition appears when meshing with the sprocket, influences equipment life. Compared with chain transmission, the service life of the gear transmission is often longer, and the service life of the equipment can be prolonged. The specific structure of each mechanism component is not limited herein.

In some embodiments, in order to ensure the smoothness of the telescopic movement of the middle yoke, as shown in fig. 3A to 3D, the middle yoke 12 may be formed with first guide grooves D1 on both sides of the rack C on the end surface facing the fixed yoke 11. And the fixed yoke 11 may be mounted with a plurality of support members 14 at corresponding positions. The plurality of support members 14 may be engaged with the first guide groove D1. These support members 14 are provided at intervals along the longitudinal direction of the fixed yoke 11. In this way, the support member 14 can perform a supporting and guiding function when the middle yoke 12 performs a telescopic movement with respect to the fixed yoke 11. Multiple of embodiments of the present disclosure generally refer to at least two.

As an example, the support member 14 may be a support block 141. The heights of the supporting blocks 141 are the same, i.e., the sizes in the direction perpendicular to the ground are the same. And the mounting heights of the supporting blocks 141 on the fixed yoke 11 are the same. Here, each of the supporting blocks 141 may be symmetrically installed at both sides of the fixed yoke 11. Alternatively, they may be alternately installed at both sides thereof at intervals. For example, the support member 14 may be a roller 142 to ensure smooth extension and contraction of the middle fork arm and reduce resistance. The diameter and mounting height of each roller 142 are the same. For another example, the plurality of supporting members 14 may be a combination of a plurality of supporting blocks 141 and a plurality of rollers 142 in order to reduce the production cost while securing the movement stability. As can be seen in fig. 3C, the plurality of supporting blocks 141 and the plurality of rollers 142 may be symmetrically disposed at both sides of the fixed yoke 11. Meanwhile, the supporting blocks 141 and the rollers 142 positioned at the same side of the fixed yoke 11 may be alternately arranged at intervals.

In some embodiments, as shown in fig. 3C and 3D, the diameter of the roller 142 may be greater than the height of the support block 141. Thus, when the middle fork arm 12 moves telescopically, the roller (especially the surface facing the middle fork arm) can roll along with the contact position of the first guide groove D1. Meanwhile, the supporting block 141 can be used for positioning limitation, and other movements of the middle fork arm except the telescopic movement in the horizontal direction are avoided or reduced. In addition, the roller 142 herein may be an eccentric roller. I.e., the rotational axis of the roller 142 and the mounting axis are parallel to each other but do not coincide. The eccentric structure can reduce or avoid the influence of factors such as manufacturing or installation errors, and the like, so that the installation position can be adjusted adaptively.

It should be noted that the middle yoke 12 may be located at an upper end of the fixed yoke 11, and the transmission assembly 13 may be located at a lower end of the fixed yoke 11. Wherein the upper end and the lower end are opposite ends. While the lower end is typically the end facing the ground. This can raise the usable (length) dimension of the overall yoke. Meanwhile, the occurrence of equipment failure or damage caused by deposition of foreign matters such as dust can be reduced or avoided.

Further, in order to increase the telescopic range of the forks, the first single-fork mechanism 1 and the second single-fork mechanism 2 further comprise upper fork arms. As shown in fig. 3A to 3D, the middle yoke 12 may be located between the fixed yoke 11 and the upper yoke 15.

Here, in order to achieve the telescopic movement of the upper yoke 15, as shown in fig. 3C, both sides of the middle yoke 12 may be provided with a traction member 16 and a guide roller 17. As shown in fig. 4A, the guide roller 17 may be installed at a position of the middle yoke 12 near both ends. Meanwhile, as shown in fig. 3C, both sides of the fixed yoke 11 may be provided with an adjusting member T for adjusting the tension of the traction member 16 at a position near the first end. The first end and the second end are generally two opposite ends in the length direction. And the second end is typically the end of the fork that extends out when it is extended and retracted, as shown at the right end in fig. 3A-3C.

At this time, one end of the traction member 16 may be connected to a first end (left end as viewed in the drawing) of the upper yoke. The other end of the traction member 16 may bypass a guide roller 17 located at the second end (right end as shown in the drawing) of the center yoke 12 and be connected to the adjustment member T. Thus, when the middle fork arm 12 extends, the guide roller 17 at the second end can push the traction component 16, so that the upper fork arm is driven to extend forward. The traction means may be a chain (e.g. a pallet chain) or a rope or the like. In addition, in order to move the traction member 16 along the guide roller 17, the guide roller 17 may be a belt edge (belt flange) roller as shown in fig. 4B. The guide roller 17 can be fixed to the intermediate yoke 12 by means of a bearing ZC, a swivel Z and an end cap DG. In addition, both sides of the middle yoke 12 may be formed with guide grooves for receiving the traction members 16 and the guide rollers 17.

In some embodiments, to ensure the stability of the telescopic movement of the upper yoke, as shown in fig. 3D, the end surface of the upper yoke 15 facing the middle yoke 12 may be formed with a groove for receiving the middle yoke 12. I.e. the upper yoke 15 may be snapped onto the middle yoke 12. A plurality of support members 18 may also be provided on both inner side walls of the recess. These support members 18 may be spaced apart along the length of the upper yoke 15. Meanwhile, the middle yoke 12 may also be formed at both sides thereof with second guide grooves D2. The second guide groove D2 may cooperate with the support member 18 in the recess to guide and support the upper yoke 15. The support members 18 may be rollers, such as eccentric rollers as described above, which may be symmetrically mounted on both sides of the upper yoke 15.

It can be appreciated that in the telescopic fork of the present disclosure, the connection manner of the driving mechanism and the transmission assembly can be set according to the actual situation. As an example, as shown in fig. 5, the transmission assembly 13 may include a plurality of transmission gears 131. These transmission gears 131 may be arranged in a longitudinal direction of the fixed yoke 11. The plurality of transmission gears 131 may be large gears meshed with each other, or may be a gear combination of alternately arranged large gears and small gears. Thus, the gear transmission acting surface can be increased, the transmission efficiency is improved, and the weight of equipment is reduced.

As an example, the driving mechanism 3 may be directly connected to a certain transmission gear among the plurality of transmission gears 131. For example, the transmission gear can be connected with a rotating shaft of the driving motor. Meanwhile, the transmission gear can be coaxially arranged with a corresponding transmission gear in the second single fork mechanism. For another example, the transmission assembly may also include a transmission case. The transmission case may be fixed to the fixed yoke. At the same time, the gear in the transmission case can be meshed with one of the plurality of transmission gears. As shown in fig. 1 and 2, the gear box 132 in the first single-fork mechanism 1 and the gear box 232 in the second single-fork mechanism 2 may be connected by a universal joint W.

Here, the driving mechanism 3 may include a driving motor 31 and a driving gear 32. The driving gear 32 is mounted on the rotation shaft of the driving motor 31. At this time, the transmission case 132 in the first single fork mechanism may be provided with a driven gear on the outer end surface on the same side as the drive gear 32. Wherein, driven gear and the gear in the transmission case are coaxial setting. The driven gear and the drive gear 32 may be connected by a transmission member, thereby effecting connection of the drive mechanism to the transmission assembly. The transmission member may be a member capable of transmitting power such as a chain or a belt. In addition, the driving motor 31 may be a servo motor with an encoder at the tail end. Thus, the travelling distance of the telescopic fork can be calculated through the number of turns of the encoder.

As can be seen in fig. 6A to 6D, the overall structure of the gear box 132 and the gear box 232 is substantially the same, and is composed of a shaft Z, a key J, a shaft end cover DG1, a bearing ZC, a spacer GT, a box XT, a gear CL, and a bearing end cover DG 2. In contrast, the axis Z in the gear box 132 is longer than the axis Z in the gear box 232. And the two ends of the central shaft Z of the transmission case 132 extend out, one end is connected with the universal coupling, and the other end is connected with the driven gear.

In some embodiments, to increase the useful life of the telescoping forks, as shown in FIGS. 1 and 2, the driven gear may be mounted on the shaft of the transmission box 132 by a torque limiter 19. Thus, when the desired torque exceeds a set point due to overload (overweight of the load) or mechanical failure, it limits the torque transmitted by the transmission system in the form of slip. When the overload situation disappears, the connection can be restored by itself. So that the device can be overload protected.

In addition, each gear mentioned in the embodiments of the present disclosure, such as a transmission gear, a driven gear, a driving gear, and the like, may employ a positive displacement gear. The positive displacement gear is usually a gear cut by the dividing line of the rack knife far away from the center of the gear, and the displacement coefficient of the positive displacement gear is usually positive. Therefore, the abrasion resistance of the gear can be improved, the service life of the gear is prolonged, and the service life of the telescopic fork is prolonged. However, when the chain wear pitch becomes large, the chain is easily disjointed when engaged with the sprocket, and the cost of reinstallation and maintenance is high. The maintenance costs of the gear drive may be relatively low compared to chain drives.

In some embodiments, as shown in fig. 2, a detecting component JC may be further installed on the telescopic fork, for detecting whether the upper fork arm is retracted and reset. As an example, the detection assembly may be mounted on the first single-fork mechanism or the second single-fork mechanism. For another example, to ensure that the upper fork arms in both single fork mechanisms retract to zero reset, a detection assembly may be mounted on both single fork mechanisms.

The structure of the detection unit JC is not limited, and may be a contact type detection unit or a noncontact type detection unit. As an example, the detection component JC may be an infrared transceiver and a baffle. The infrared transceiver may be mounted on a fixed yoke (or upper yoke). The baffle may be mounted to the upper yoke (or fixed yoke). When the baffle blocks the infrared rays emitted by the infrared emitter and the infrared receiver cannot receive the infrared rays, the upper fork arm can be determined to shrink and reset. For another example, the detection component JC may be a proximity switch and a sensing board. As shown in fig. 7, the proximity switch KG may be mounted on one side of the fixed yoke 11 by a mounting plate AZB. And the sensing plate GY may be mounted on the same side of the upper yoke. Thus, during retraction of the upper yoke, a command signal may be generated when the proximity switch KG detects the approaching sensor plate GY, indicating that the upper yoke has been reset.

The embodiment of the disclosure also provides a stacker. The stacker may include: the device comprises a device main body, a telescopic fork and a moving mechanism. Wherein the device body may function as a support. And the telescopic fork can be mounted on the apparatus body by a moving mechanism. Which may employ the structure of the telescopic fork described in any of the implementations of the above embodiments. The moving mechanism can be installed on the equipment main body as well and is used for driving the telescopic fork to do lifting motion along the equipment main body, thereby realizing the stacking function. The structure of the moving mechanism is not limited as well, and can be a motor, a belt, a hydraulic rod or the like.

The foregoing description is only of the preferred embodiments of the present disclosure and description of the principles of the technology being employed. It will be appreciated by those skilled in the art that the scope of the invention in the embodiments of the present disclosure is not limited to the specific combination of the above technical features, but encompasses other technical features formed by any combination of the above technical features or their equivalents without departing from the spirit of the invention. Such as the above-described features, are mutually substituted with (but not limited to) the features having similar functions disclosed in the embodiments of the present disclosure.

Claims (12)

1. A telescopic pallet fork, comprising:

the first single fork mechanism and the second single fork mechanism are used for bearing goods;

the first single-fork mechanism and the second single-fork mechanism comprise fixed fork arms, middle fork arms and transmission components, and the fixed fork arms are positioned between the middle fork arms and the transmission components;

the driving mechanism is connected with the transmission assembly of the first single-fork mechanism, and the transmission assembly of the first single-fork mechanism is connected with the transmission assembly of the second single-fork mechanism;

the middle fork arm is provided with a rack on the end face facing the fixed fork arm, and the rack extends along the length direction of the middle fork arm;

the transmission assembly comprises a transmission gear and is fixed on the fixed fork arm;

the fixed fork arm is provided with a matching through hole, and the transmission gear is meshed with the rack on the middle fork arm through the matching through hole so as to realize the telescopic movement of the middle fork arm under the action of the driving mechanism.

2. The telescopic fork according to claim 1, wherein the middle fork arm is formed with first guide grooves on both sides of the rack on an end surface facing the fixed fork arm;

the fixed fork arm is provided with a plurality of supporting parts matched with the first guide grooves, and the supporting parts are arranged at intervals along the length direction of the fixed fork arm.

3. The telescopic fork of claim 2, wherein the plurality of support members comprises a plurality of rollers and a plurality of support blocks, the plurality of rollers are symmetrically disposed on both sides of the fixed fork arm, the plurality of support blocks are symmetrically disposed on both sides of the fixed fork arm, and the rollers on the same side are alternately disposed at intervals with the support blocks.

4. A telescopic pallet fork according to claim 3, wherein the rotational axis of the roller is parallel misaligned with the mounting axis and the diameter of the roller is greater than the height of the support block.

5. The telescoping fork of claim 2, wherein said middle yoke is located at an upper end of said fixed yoke and said drive assembly is located at a lower end of said fixed yoke; the upper end and the lower end are opposite ends, and the lower end is one end facing the ground.

6. The telescoping fork of claim 1, wherein the first and second single-prong mechanisms further comprise an upper prong, the middle prong being located between the fixed prong and the upper prong.

7. The telescopic fork according to claim 6, wherein the end surface of the upper fork arm facing the middle fork arm is formed with a groove for accommodating the middle fork arm, and a plurality of supporting members are arranged on two inner side walls of the groove and are arranged at intervals along the length direction of the upper fork arm;

second guide grooves are formed on two side surfaces of the middle fork arm and matched with the supporting parts in the grooves.

8. The telescopic fork according to claim 7, wherein both sides of the middle fork arm are provided with traction members and guide rollers, the guide rollers being installed at positions of the middle fork arm near both ends;

the two sides of the fixed fork arm are provided with adjusting parts at positions close to the first end, and the adjusting parts are used for adjusting the tension force of the traction part;

one end of the traction component is connected with the first end of the upper fork arm, and the other end of the traction component bypasses the guide roller at the second end of the middle fork arm and is connected with the adjusting component;

the first end and the second end are two opposite ends in the length direction, and the second end is one end extending out when the fork stretches out and draws back.

9. The telescopic pallet fork according to claim 6, wherein a detection assembly is further mounted on the telescopic pallet fork for detecting whether the upper fork arm is retracted and reset;

the detection assembly comprises a proximity switch and a sensing plate, wherein the proximity switch is arranged on one side face of the fixed fork arm, and the sensing plate is arranged on the same side face of the upper fork arm.

10. The telescopic pallet fork according to any one of claims 1-9, wherein the drive assembly comprises a plurality of drive gears arranged in a longitudinal direction of the fixed fork arms;

the transmission assembly further comprises a transmission box which is fixed on the fixed fork arm, and a gear in the transmission box is meshed with one transmission gear in the plurality of transmission gears;

the transmission case in the first single-fork mechanism is connected with the transmission case in the second single-fork mechanism through a universal coupling.

11. The telescopic pallet fork of claim 10, wherein the drive mechanism comprises a drive motor and a drive gear, the drive gear being mounted on a shaft of the drive motor;

the transmission case in the first single-fork mechanism is provided with a driven gear on the outer end face on the same side as the driving gear, and the driven gear is connected with the driving gear through a transmission part;

the driven gear is arranged on a rotating shaft of the transmission case through a torque limiter, and each gear adopts a positive displacement gear.

12. A stacker comprising:

an apparatus main body;

a telescopic fork, adopting the structure of the telescopic fork as claimed in any one of claims 1-11;

and the moving mechanism is arranged on the equipment main body and used for driving the telescopic fork to do lifting motion along the equipment main body.