1. The utility model provides a high fork truck safety formula fork is piled to unmanned, includes fork frame (1) and symmetry setting two fork (2) that just can remove about just in fork frame (1), fork (2) are got a group by the fork of the upright part of vertical setting and level setting and are constituteed, are "L" shape structure, its characterized in that: an electric lifting sliding table (3) electrically connected with a forklift control system on a forklift is fixedly arranged at the center of the front surface of the fork frame (1), and a connecting rod (7) capable of moving up and down is transversely arranged on the electric lifting sliding table (3); a group of distance measuring adjusting devices (5) capable of moving up and down are respectively arranged on the symmetrical surfaces of the two forks (2), the two groups of distance measuring adjusting devices (5) are symmetrical left and right and are electrically connected with a forklift control system, and the tops of the distance measuring adjusting devices (5) are movably connected with the connecting rod (7) through a connecting plate; the pallet fork is characterized in that a pallet detection mechanism (4) electrically connected with the forklift control system is movably arranged on the vertical part of the pallet fork (2), and the pallet detection mechanism (4) can sense the position information of a pallet (8) which is forked on the forking part.

2. The unmanned forklift safety pallet fork of claim 1, wherein: the front end of the forking part on the fork (2) is sleeved with a touch detection mechanism (6) which can be movably connected with the front and the back of the fork.

3. The unmanned forklift safety pallet fork of claim 1, wherein: the electric lifting sliding table (3) comprises a sliding table support (31), a driving motor (32) is fixedly arranged at the top of the sliding table support (31), a rotary screw rod (33) is vertically arranged on the front surface of the sliding table support, the top of the rotary screw rod (33) penetrates through the sliding table support (31) to be in transmission connection with the driving motor (32), the bottom of the rotary screw rod (33) is movably connected onto the sliding table support (31) through a screw rod bearing (37), a sliding block (35) in clearance fit with the screw rod bearing (37) is sleeved outside the screw rod bearing (37), the sliding block (35) is fixedly connected with a screw rod nut (34) matched with the outside of the rotary screw rod (33), the screw rod nut (34) can be driven to move up and down by rotating the rotary screw rod (33) so as to drive the sliding block (35) to move synchronously, and the connecting rod (7) is fixedly connected to the front surface of the sliding block (35) through a bolt; the position symmetry that slip table support (31) openly is located rotatory lead screw (33) left and right sides is provided with guide post (36) of two vertical settings, the position that corresponds guide post (36) on slider (35) sets up the direction slide opening of two upper and lower intercommunications, and two guide post (36) wear to establish respectively in two direction connecting holes that correspond, guide post (36) with direction slide opening sliding fit.

4. The unmanned forklift safety pallet fork of claim 1, wherein: the tray detection mechanism (4) comprises a movable turning plate (41) which can be matched with the front face of the vertical part on the fork (2), the position, close to the top, of the side face of the movable turning plate (41) is movably connected to the vertical part of the fork (2) through a pin shaft (43), a pin is fixedly arranged at the position, located on the rear side of the pin shaft (43), of the side face of the movable turning plate (41), a positioning screw (45) is fixedly arranged on the face, on the same side with the pin, of the vertical part of the fork (2), the positioning screw (45) is close to the bottom position of the vertical part and vertically corresponds to the pin, a first reset spring (44) is connected between the positioning screw (45) and the pin, and the lower end of the front face of the movable turning plate (41) obliquely bounces forwards under the action of the first reset spring (44) and the pin shaft (43); the side surface of the upright part of the pallet fork (2) is fixedly provided with a first micro switch (42) which is electrically connected with the forklift control system, the first micro switch (42) is positioned right above the side surface of the movable turning plate (41) and close to the top of the side surface of the movable turning plate (41), the first micro switch is fixed on the pallet fork (2) through a switch fixing bolt (46), and when the movable turning plate (41) is pushed backwards, the top of the side surface of the movable turning plate (41) can touch the corresponding first micro switch (42).

5. The unmanned forklift safety pallet fork of claim 1, wherein: guide sliding chutes (71) are symmetrically arranged at the positions, close to the left end and the right end, of the front face of the connecting rod (7), the guide sliding chutes (71) are transversely arranged, a connecting plate is arranged in each guide sliding chute (71), the connecting plate is in sliding fit with the guide sliding chutes (71) from left to right, and sleeve-joint holes which are communicated up and down are formed in the connecting plate; the distance measurement adjusting mechanism (5) comprises a sensor support (51), a laser distance measurement sensor (54) electrically connected with the forklift control system is fixedly arranged at a position, close to the bottom, on the front surface of the sensor support (51), a pull rod (55) is fixedly arranged at a position, close to the top, of the sensor support (51), the pull rod (55) is vertically arranged, the top of the pull rod passes through a sleeve hole in a corresponding connecting plate and upwards extends to the outer side of the top of the sleeve hole, an adjusting screw (56) in threaded fit with the pull rod (55) is arranged at a position, extending to the outer side of the top of the sleeve hole, on the pull rod (55), the position of the pull rod (55) on the connecting plate can be limited through the adjusting screw (56), and slipping is prevented; the back of the sensor support (51) is provided with a roller (57) at a position close to the bottom, a Z-direction sliding block (52) is fixedly arranged at a position close to the top, a guide rail (53) in sliding fit with the Z-direction sliding block (52) is arranged on the Z-direction sliding block, and the guide rail (53) is vertically and fixedly arranged on the side face of the vertical part of the fork (2) through a bolt.

6. The unmanned forklift safety pallet fork of claim 5, wherein: the laser ranging sensor (54) and the pull rod (55) are fixedly connected to the sensor support (51) through a fixing bolt (58).

7. The unmanned forklift safety pallet fork of claim 2, wherein: the touch detection mechanism (6) comprises a fork sleeve (61) which can be matched with the front end of the forking part on the fork (2) in a sleeved mode, a second reset spring (64) which is abutted against the front end of the forking part is arranged inside the fork sleeve (61), a positioning hole communicated with the inside of the fork sleeve is formed in the top of the forking part, a guide limiting groove with an upward opening is formed in the position, close to the front end, of the top of the forking part, a limiting sliding block (62) in sliding fit with the guide limiting groove is arranged in the guide limiting groove, the fork sleeve (61) is fixedly connected onto the limiting sliding block (62) through a sliding block bolt (65), a second micro switch (64) is fixedly arranged at the position, close to the rear end of the fork sleeve (61), of the forking part is arranged on the inner side of the forking part, the second micro switch (64) is electrically connected with a forklift control system, and the fork sleeve (61) can touch the corresponding second micro switch (64) when moving backwards.

8. The unmanned forklift safety pallet fork of claim 2, wherein: the top surfaces of the fork sleeves (61) are flush with the top surface of the forking part on the pallet fork (2), two second return springs (64) are arranged in each fork sleeve (61), and an elastic distance is kept between the rear end of each fork sleeve (61) and the second microswitch (64) under the action of the second return springs (64).

Background

Along with the continuous progress of science and technology, the unmanned technology is gradually popularized in various industries, and the unmanned forklift is undoubtedly one of the applications which are rapidly popularized.

The unmanned forklift for stacking does not have great difference from the traditional forklift for manually driving in essential characteristics, and is mainly used for two modes of plane carrying and stacking. The fork position is judged by the visual sense of a driver when the manually-driven forklift with the stacking mode stacks goods or picks up the goods from a high place, the unmanned forklift needs to judge by various sensors when in stacking operation, and the main parts related to the picking and placing of the unmanned forklift are the fork assembled by the forklift, a pallet bearing the goods, a goods shelf arranged in a warehouse and the like.

The existing unmanned high-stacking forklift operation flow mainly comprises the following steps: the vehicle starts from a parking space, then lifts the fork to a certain height away from the ground, and starts to walk to a target point for carrying goods according to an instruction sent by a scheduling system, when a goods tray is forked from the ground, a control system of the vehicle can adjust the height of the fork to a position which can be just inserted into the bottom of the tray according to a task instruction, the height of the fork from the ground is measured by a height encoder arranged on a vehicle door frame, due to the limitation of the structure, the measured accurate height can only be used as a standard according to a fork hanging frame of the fork, and the height of the front end of the fork inserted into the tray can be changed along with the levelness of the ground, so that some protective devices are required to be loaded on the fork, and the collision between the fork and the tray is prevented. At present, the laser measuring sensor is fixedly arranged on the side surface of the fork in the industry, and the laser beam of the sensor is parallel to the upper surface of the fork and has a fixed distance. The protective performance of the structure is not problematic when empty pallet forks take pallets, but when the pallets are loaded on the pallet forks, the detection mode of the side-fixed sensor loses the effect when a vehicle stacks the pallets with goods or places the pallets on a storage shelf, because the lowest point of the pallet forks is 80-100mm lower than the detection point of the sensor, although the vehicle has a reserved space when controlling the height, the lifting of the forklift has certain flexibility by a hydraulic mode, the pallet forks bearing the goods can generate corresponding deformation along with the weight of the load, the levelness of the ground directly influences the verticality of the forklift gantry and the ground, the height change of the lowest point of the pallet loading the goods can be influenced by a series of factors, and the safety influence is exerted on the goods loading into the shelf or the goods stacking.

Disclosure of Invention

The invention aims to solve the technical problem of providing a safety type fork of an unmanned high-rise forklift, which can improve the safety of the unmanned high-rise forklift during forking and stacking of goods.

In order to solve the technical problems, the invention is realized by the following technical scheme: a safety type fork of an unmanned forklift comprises a fork frame and two forks which are symmetrically arranged on the front side of the fork frame and can move left and right, wherein each fork is composed of a vertical part which is vertically arranged and a fork taking part which is horizontally arranged and is of an L-shaped structure, an electric lifting sliding table which is electrically connected with a forklift control system on the forklift is fixedly arranged in the center of the front side of the fork frame, and a connecting rod which can move up and down is transversely arranged on the electric lifting sliding table; a group of distance measuring adjusting devices capable of moving up and down are respectively arranged on the symmetrical surfaces of the two forks, the two groups of distance measuring adjusting devices are symmetrical left and right and are electrically connected with a forklift control system, and the tops of the distance measuring adjusting devices are movably connected with the connecting rod through a connecting plate; the pallet fork is characterized in that a pallet detection mechanism electrically connected with the forklift control system is movably arranged on the vertical part of the pallet fork, and the pallet detection mechanism can sense the pallet position information forked on the forking part.

Furthermore, the front end of the fork-taking part on the goods fork is sleeved with a touch detection mechanism which can be movably connected with the front end and the back end of the fork-taking part.

Furthermore, the electric lifting sliding table comprises a sliding table support, a driving motor is fixedly arranged at the top of the sliding table support, a rotary screw rod is vertically arranged on the front surface of the sliding table support, the top of the rotary screw rod penetrates through the sliding table support to be in transmission connection with the driving motor, the bottom of the rotary screw rod is movably connected onto the sliding table support through a screw rod bearing, a sliding block in clearance fit with the screw rod bearing is sleeved outside the screw rod bearing, the sliding block is fixedly connected with a screw rod nut matched with the outer part of the rotary screw rod, the screw rod nut can be driven to move up and down by rotating the rotary screw rod to drive the sliding block to move synchronously, and the connecting rod is fixedly connected to the front surface of the sliding block through a bolt; the sliding table support is characterized in that two guide posts which are vertically arranged are symmetrically arranged at positions, located on the left side and the right side of the rotary screw rod, of the front face of the sliding table support, two guide sliding holes which are communicated up and down are formed in the position, corresponding to the guide posts, of the sliding block, the two guide posts are respectively arranged in the two corresponding guide connecting holes in a penetrating mode, and the guide posts are in sliding fit with the guide sliding holes.

Furthermore, the tray detection mechanism comprises a movable turning plate which can be matched with the front side of the vertical part on the fork, the position, close to the top, of the side surface of the movable turning plate is movably connected to the vertical part of the fork through a pin shaft, a pin is fixedly arranged at the position, located on the rear side of the pin shaft, of the side surface of the movable turning plate, a positioning screw is fixedly arranged on the surface, on the same side with the pin, of the vertical part of the fork, the positioning screw is close to the bottom position of the vertical part and vertically corresponds to the pin, a first reset spring is connected between the positioning screw and the pin, and the lower end of the front side of the movable turning plate obliquely bounces forwards under the action of the first reset spring and the pin shaft; the side surface of the vertical part of the fork is fixedly provided with a first microswitch which is electrically connected with the fork truck control system, the first microswitch is positioned right above the side surface of the movable turning plate and close to the top of the side surface of the movable turning plate, the first microswitch is fixed on the fork through a switch fixing bolt, and when the movable turning plate is pushed backwards, the top of the side surface of the movable turning plate can touch the corresponding first microswitch.

Furthermore, guide chutes are symmetrically arranged at the positions, close to the left end and the right end, of the front face of the connecting rod, the guide chutes are transversely arranged, a connecting plate is arranged in each guide chute, the connecting plates are in sliding fit with the guide chutes left and right, and sleeve holes which are communicated up and down are arranged on the connecting plates; the distance measurement adjusting mechanism comprises a sensor support, a laser distance measurement sensor electrically connected with the forklift control system is fixedly arranged at a position, close to the bottom, of the front face of the sensor support, a pull rod is fixedly arranged at a position, close to the top, of the sensor support, the pull rod is vertically arranged, the top of the pull rod penetrates through a sleeve hole in a corresponding connecting plate and extends upwards to the outer side of the top of the sleeve hole, an adjusting screw in threaded fit with the pull rod is arranged at a position, extending to the outer side of the top of the sleeve hole, on the pull rod, and the position of the pull rod on the connecting plate can be limited through the adjusting screw to prevent slipping; the back of the sensor support is provided with a roller near the bottom, a Z-direction sliding block is fixedly arranged near the top, a guide rail in sliding fit with the Z-direction sliding block is arranged on the Z-direction sliding block, and the guide rail is vertically and fixedly arranged on the side face of the vertical part of the fork through a bolt.

Furthermore, the laser ranging sensor and the pull rod are fixedly connected to the sensor support through fixing bolts.

Further, touching detection mechanism including can with fork front end cup joint complex fork cover on the goods fork, the inside second reset spring who conflicts with fork front end that is provided with of fork cover, the top is provided with rather than the inside locating hole that is linked together, the position that fork top is close to the front end is provided with the ascending direction spacing groove of opening, is provided with rather than sliding fit's spacing slider in the direction spacing groove, the fork cover passes through slider bolt fixed connection on spacing slider, the inboard fixed position that is close to the fork cover rear end of fork of taking portion is provided with the second micro-gap switch, this second micro-gap switch and fork truck control system electric connection, the fork cover can touch corresponding second micro-gap switch when backward moving.

Furthermore, the top surface of the fork sleeve is flush with the top surface of the fork taking part on the fork, two second return springs are arranged in each fork sleeve, and an elastic space is reserved between the rear end of the fork sleeve and the second microswitch under the action of the second return springs.

Compared with the prior art, the invention has the advantages that: the safety type pallet fork of the unmanned high-stacking forklift can be accurately inserted into the pallet when the unmanned high-stacking forklift is used for unmanned high-stacking forklift operation, the pallet can not collide with each other when placed on a pallet or taken out from the pallet, the safety of the unmanned high-stacking forklift when the pallet is forked to pick and stack goods is improved, and the safety type pallet fork is simple in structure and easy to popularize.

Drawings

The invention is further described below with reference to the accompanying drawings.

FIG. 1 is a schematic view of a safety pallet fork of an unmanned forklift truck according to the present invention;

FIG. 2 is a schematic structural view of an electric lifting sliding table in a safety pallet fork of the unmanned forklift truck according to the invention;

FIG. 3 is a schematic structural view of a pallet detecting mechanism in a safety pallet fork of the unmanned forklift truck according to the invention;

FIG. 4 is a schematic structural view of a distance measuring and adjusting mechanism in a safety type fork of the unmanned forklift;

fig. 5 and 6 are schematic structural views of a touch detection mechanism in a safety type fork of the unmanned forklift according to the invention;

FIG. 7 is a schematic side view of the safety pallet fork of the unmanned forklift of the present invention when empty;

FIG. 8 is a schematic side view of the safety pallet fork of the unmanned forklift of the present invention;

FIG. 9 is a schematic front view of the safety pallet fork of the unmanned forklift of the present invention when empty;

fig. 10 is a schematic front structural view of the safety type pallet fork of the unmanned forklift according to the present invention.

In the figure: 1. a fork carriage; 2. a pallet fork; 3. an electric lifting sliding table; 31. a sliding table bracket; 32. a drive motor; 33. rotating the screw rod; 34. a stop rod nut; 35. a slider; 36. a guide post; 37. a screw bearing; 4. a tray detection mechanism; 41. a movable turning plate; 42. a first microswitch; 43. a pin shaft; 44. a first return spring; 45. a set screw; 46. a switch fixing bolt; 5. a distance measurement adjusting mechanism; 51. a sensor holder; 52. a Z-direction slider; 53. a guide rail; 54. a laser ranging sensor; 541. detecting a probe beam; 55. a pull rod; 56. adjusting screws; 57. a roller; 58. fixing the bolt; 6. a touch detection mechanism; 61. a fork sleeve; 62. a limiting slide block; 63. a second microswitch; 64. a second return spring; 65. a slider bolt; 7. a connecting rod; 71. a guide chute; 8. a tray.

Detailed Description

The invention is described in detail below with reference to the following figures and embodiments:

fig. 1 shows a safety type fork of an unmanned forklift truck, which comprises a fork frame 1 and two forks 2 symmetrically arranged on the front side of the fork frame 1 and capable of moving left and right, wherein the fork frame 1 is matched with a track of a forklift truck portal channel steel through rollers arranged on supporting plates on two sides, and then lifting action is realized through chain pulling, the forks 2 are composed of a vertical part vertically arranged and a fork taking part horizontally arranged and are of an L-shaped structure, an electric lifting sliding table 3 electrically connected with a forklift truck control system on the forklift truck is fixedly arranged in the center of the front side of the fork frame 1, and a connecting rod 7 capable of moving up and down is transversely arranged on the electric lifting sliding table 3; a group of distance measuring adjusting devices 5 capable of moving up and down are respectively arranged on the symmetrical surfaces of the two forks 2, the two groups of distance measuring adjusting devices 5 are symmetrical left and right and are electrically connected with a forklift control system, and the tops of the distance measuring adjusting devices 5 are movably connected with the connecting rod 7 through a connecting plate; the pallet fork 2 is characterized in that a pallet detection mechanism 4 electrically connected with the forklift control system is movably arranged on the vertical part of the pallet fork, and the pallet detection mechanism 4 can sense the position information of a pallet 8 which is forked on the forking part.

In order to prevent the fork 2 from being blocked by a barrier and colliding with the fork 2, the front end of the forking part on the fork 2 is sleeved with a touch detection mechanism 6 which can be movably connected with the front end and the back end of the forking part.

As shown in fig. 2, the electric lifting sliding table 3 includes a sliding table support 31, a driving motor 32 is fixedly arranged at the top of the sliding table support 31, a rotary screw 33 is vertically arranged on the front surface of the sliding table support 31, the top of the rotary screw 33 penetrates through the sliding table support 31 to be in transmission connection with the driving motor 32, the bottom of the rotary screw is movably connected to the sliding table support 31 through a screw bearing 37, a slider 35 in clearance fit with the screw bearing 37 is sleeved outside the screw bearing 37, the slider 35 is fixedly connected with a screw nut 34 fitted outside the rotary screw 33, the screw nut 34 can be driven to move up and down by rotating the rotary screw 33 to drive the slider 35 to move synchronously, and the connecting rod 7 is fixedly connected to the front surface of the slider 35 through a bolt; the sliding table support 31 is characterized in that two guide posts 36 which are vertically arranged are symmetrically arranged at positions, located on the left side and the right side of the rotary screw rod 33, of the front surface of the sliding table support, two guide sliding holes which are communicated up and down are formed in the position, corresponding to the guide posts 36, of the sliding block 35, the two guide posts 36 are respectively arranged in the two corresponding guide connecting holes in a penetrating mode, and the guide posts 36 are in sliding fit with the guide sliding holes.

As shown in fig. 3, the tray detecting mechanism 4 includes a movable turning plate 41 capable of being in positive fit with the vertical part of the fork 2, a position of a side surface of the movable turning plate 41 near the top is movably connected to the vertical part of the fork 2 through a pin 43, a pin is fixedly arranged at a position of the side surface of the movable turning plate 41 behind the pin 43, a positioning screw 45 is fixedly arranged on a surface of the vertical part of the fork 2 on the same side as the pin, the positioning screw 45 is close to the bottom of the vertical part and vertically corresponds to the pin, a first return spring 44 is connected between the positioning screw 45 and the pin, and the lower end of the front surface of the movable turning plate 41 is obliquely sprung forward under the action of the first return spring 44 and the pin 43; a first micro switch 42 electrically connected with the forklift control system is fixedly arranged on the side surface of the upright part of the pallet fork 2, the first micro switch 42 is positioned right above the side surface of the movable turning plate 41 and close to the top of the side surface of the movable turning plate 41, the first micro switch 42 is fixed on the pallet fork 2 through a switch fixing bolt 46, and when the movable turning plate 41 is pushed backwards, the top of the side surface of the movable turning plate 41 can touch the corresponding first micro switch 42.

As shown in fig. 1, in order to ensure that the pallet fork 2 does not interfere with the distance measuring adjusting mechanism 5 when moving left and right, guide chutes 71 are symmetrically arranged at the positions of the front side of the connecting rod 7 close to the left and right ends, the guide chutes 71 are transversely arranged, a connecting plate is arranged in each guide chute 71, the connecting plate is in sliding fit with the guide chutes 71 left and right, and the connecting plate is provided with vertically communicated sleeving holes; as shown in fig. 4, the distance measuring and adjusting mechanism 5 includes a sensor bracket 51, a laser distance measuring sensor 54 electrically connected to the forklift control system is fixedly disposed at a position close to the bottom of the front surface of the sensor bracket 51, a pull rod 55 is fixedly disposed at a position close to the top, the pull rod 55 is vertically disposed, the top of the pull rod 55 passes through a sleeve hole on a corresponding connecting plate and extends upwards to the outside of the top of the sleeve hole, an adjusting screw 56 in threaded fit with the pull rod 55 is disposed at a position on the pull rod 55 extending to the outside of the top of the sleeve hole, and the position of the pull rod 55 on the connecting plate can be limited by the adjusting screw 56 to prevent slipping; a roller 57 is arranged at a position, close to the bottom, of the back surface of the sensor support 51, a Z-direction sliding block 52 is fixedly arranged at a position, close to the top, of the back surface of the sensor support 51, a guide rail 53 in sliding fit with the Z-direction sliding block 52 is arranged on the Z-direction sliding block 52, and the guide rail 53 is vertically and fixedly arranged on the side surface of the vertical part of the pallet fork 2 through a bolt; the fork 2 can drive the ranging adjusting mechanism 5 to synchronously move when moving, and the ranging adjusting mechanism 5 moves synchronously in the guide sliding groove 71 of the connecting rod 7 without interference when moving leftwards and rightwards due to the sliding fit between the connecting plate and the connecting rod 7.

In order to facilitate the installation and the removal of the laser ranging sensor 54 and the pull rod 55 on the sensor bracket 51, the laser ranging sensor 54 and the pull rod 55 are fixedly connected to the sensor bracket 51 through a fixing bolt 58.

As shown in fig. 5 and 6, the touch detection mechanism 6 includes a fork sleeve 61 capable of being in fit with the front end of the forking part of the fork 2, a second return spring 64 abutting against the front end of the forking part is arranged inside the fork sleeve 61, a positioning hole communicated with the inside of the fork sleeve is arranged at the top of the fork sleeve, a guiding limiting groove with an upward opening is arranged at a position close to the front end of the top of the forking part, a limiting slide block 62 in sliding fit with the guiding limiting groove is arranged in the guiding limiting groove, the fork sleeve 61 is fixedly connected to the limiting slide block 62 through a slide block bolt 65, a second micro switch 64 is fixedly arranged at a position close to the rear end of the fork sleeve 61 inside the forking part, the second micro switch 64 is electrically connected with a forklift control system, and the fork sleeve 61 can touch the corresponding second micro switch 64 when moving backwards.

In order to prevent the fork sleeve 61 from interfering with the insertion between the forking part and the tray 8, the top surface of the fork sleeve 61 is flush with the top surface of the forking part on the pallet fork 2, two second return springs 64 are arranged in each fork sleeve 61, and an elastic distance is kept between the rear end of the fork sleeve 61 and the second microswitch 64 under the action of the second return springs 64.

The specific working principle is as follows: when the unmanned forklift is used for forking the goods tray 8 on the ground, as shown in fig. 7 and 9, when the goods tray 8 is not loaded on the fork 2, the slide block 35 on the electric lifting sliding table 3 is at the position of the top dead center (i.e. the highest position), the connecting rod 7 mounted on the slide block 35 pulls the pull rod 55 on the sensor bracket 51 through the connecting plate, so that the laser ranging sensor 54 is at the highest position, and the detection light beam 541 of the laser ranging sensor 54 is close to the upper surface of the forking part on the fork 2. As shown in fig. 8 and 10, when the pallet 2 is loaded with the pallet tray 8, the movable flap 41 of the pallet detection mechanism 4 is pushed to the vertical position of the upright part of the pallet 2, the top of the side surface of the movable flap 41 pushes the first micro switch 42 upwards to close, the first micro switch 42 feeds back a signal to the forklift control system, the forklift control system receives the signal that the first micro switch 42 is opened, the forklift control system outputs a signal to the driving motor 32 of the electric lift slide 3, the driving motor 32 starts to rotate and drives the rotary lead screw 33 to rotate, the rotary lead screw 33 rotates to drive the lead screw nut 34 to move downwards and further drive the slide block 35 to move synchronously, the slide block 35 is pushed to the bottom dead center position (i.e. the lowest position) through the lead screw nut 34, the connecting rod 7 mounted on the slide block 35 synchronously descends to the bottom dead center position, at this time, the sensor bracket 51 mounted with the laser distance measuring sensor 54 loses the traction force of the connecting rod 7, with the lifting of the pallet fork 2, the sensor bracket 51 provided with the laser ranging sensor 54 keeps moving vertically downwards with the guide rail 53 through the Z-direction slide block 52 under the action of self gravity, and automatically slides downwards until the adjusting screw 56 on the pull rod 55 is contacted with the connecting plate on the connecting rod 7 again to stop. At this moment, the fork 2 of the unmanned stacking forklift is completely hidden in the tray 8, the laser ranging sensor 54 falls to the lowest point position of the tray 8, the detection light beam 541 of the laser ranging sensor 54 is close to the lower surface of the forking part on the fork 2, when the unmanned stacking forklift places the tray 8 on the rack, the horizontal heights of the laser ranging sensor 54 and the unmanned stacking forklift cannot interfere with each other, judgment can be accurately made, and the situation that the position exceeds the reserved height of the system is not worried. After the unmanned forklift is placed on the tray 8, goods are delivered, 2 withdraws from the tray 8, the movable turning plate 41 on the tray detection mechanism 4 loses the thrust applied by the tray 8, the movable turning plate turns over a certain angle under the traction force of the first reset spring 44, the front end of the bottom of the movable turning plate bounces previously, the lower part of the rear side of the top of the side surface turns over, meanwhile, the first microswitch 42 installed on the side surface of the pallet fork 2 does not have the thrust of the side edge of the movable turning plate 41 and returns to a closing state, the forklift control system sends a reverse operation signal to the driving motor 32 on the electric lifting sliding table 3 after receiving the closing signal of the first microswitch 42, the driving motor 32 rotates in the direction, the lead screw nut 34 drives the sliding block 35 to ascend, and the sliding block 35 drives the connecting rod 7 to ascend synchronously and return to the upper dead center position. In order to prevent the side surfaces of the front ends of the forks 2 from interfering with each other, a touch detection mechanism 6 is designed at the front end of each fork 2, under normal conditions, the fork sleeve 61 is ejected out to the front of the fork 2 by the second return spring 64, and a certain distance is kept between the fork sleeve 61 and the second microswitch 63 by the limit slide block 62; when the pallet fork 2 extends forwards, the pallet fork meets an obstacle to block the fork sleeve 61, at the moment, the fork sleeve 61 overcomes the pushing force of the second return spring 64 to move towards one side of the second micro switch 63, when the rear end of the fork sleeve 61 completely touches the second micro switch 63, the second micro switch 63 is started, a signal for starting the first micro switch 42 is transmitted to the forklift control system, the forklift control system immediately stops the forward movement of the pallet fork 2, and the collision degree is prevented from being aggravated.

The safety type pallet fork of the unmanned high-stacking forklift can be accurately inserted into the pallet when the unmanned high-stacking forklift is used for unmanned high-stacking forklift operation, the pallet can not collide with each other when placed on a pallet or taken out from the pallet, the safety of the unmanned high-stacking forklift when the pallet is forked to pick and stack goods is improved, and the safety type pallet fork is simple in structure and easy to popularize.

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.