RU2297383C2 - Load lifter of load-lift truck - Google Patents

Abstract

FIELD: material handling facilities; loading and transporting equipment.

SUBSTANCE: invention can be used in load-lift trucks and electric loaders. Proposed load-lift truck has fixed and movable sections, load carriage with grip, flexible pulling member, for instance, chain, lift hydraulic cylinder and chain travel stop. Movable section is connected with fixed section for upwards travel, carriage is connected with movable section for upwards travel, first second and third pulleys are fitted on piston of hydraulic cylinder, on movable section and on fixed section, respectively. One end of chain is attached to load carriage and it successively passes over top of second pulley, over bottom of third pulley and over top of first pulley. Second end of chain is attached to movable section. Sprocket can be used instead of third pulley. Travel limiter of flexible pulling member is made for locking the member in any or in several fixed positions.

EFFECT: prevention of loss of carriage lifting height in rooms.

2 cl, 8 dwg

Description

The offer relates to material handling equipment and can be used in auto and electric forklifts.

A forklift is known, comprising a fixed and movable section, a load carriage, at least one lift cylinder, a chain and a pulley, the movable section being connected to the fixed section so that it can move up, the load carriage is connected to the movable section so that it can move up, on the stock a hydraulic pulley is placed, through which a chain is thrown from above, the ends of which are attached to the fixed section and the load carriage [A. Vainson Hoisting-and-transport machines, M .: Mechanical Engineering, 1989, p. 495, paragraph 5]. The disadvantage of this forklift is the lack of special free-wheeling of the ability, without increasing the overall height of the forklift, to move up the load carriage with the load gripping device to a height commensurate with the height of the cargo being handled, which limits the possibility of handling goods with this forklift in rooms with low ceilings (wagons, trucks, containers), since this forklift is not able to handle the cargo placed on the second and subsequent tiers.

Known forklift comprising a fixed and a movable section, a cargo carriage, at least one lifting cylinder, two chains and two pulleys, and the movable section is connected to the stationary section with the possibility of its movement up, the cargo carriage is connected to the mobile section with the possibility of its movement up, the first pulley is attached to the hydraulic cylinder rod, through which the first chain is thrown from above, the ends of which are attached to the movable and fixed sections, the second pulley is attached to the movable section, through ory transferred second top chain, the ends of which are fixed to the fixed section and cargo carriage [FRG patent №3139758, IPC B 66 F 9/08, 1981]. The disadvantage of this forklift is also the lack of special freewheeling.

A forklift is known, comprising a fixed and movable section, a load carriage, a lift cylinder, a freewheel, a chain and two pulleys, the movable section being connected to the fixed section with the possibility of its movement up, the cargo carriage is connected to the movable section with the possibility of moving up, to a free-wheeling cylinder is attached to the movable section, to the rod of which a first pulley is attached, through which a chain is thrown, the ends of which are attached to the movable section, and through second to the movable section of the second pulley to the load carriage [Pat. France No. 2460883, IPC B 66 F 9/08, 1980]. The disadvantage of this forklift is the presence of an additional unit - a freewheel with elements for supplying it to the movable section of high-pressure fluid, which makes this forklift difficult and unreliable.

Known forklift truck containing a stationary and movable sections, a carriage, a flexible traction element (for example, a chain), a limiter for moving a flexible traction element, a lifting cylinder and three pulleys, the movable section being connected to the stationary section with the possibility of its movement up, the cargo carriage is connected with a movable section with the possibility of its upward movement, the lifting cylinder and the limiter for moving the flexible traction element are attached to the fixed section, the first pulley is attached is attached to the rod of the lift cylinder, the second pulley is attached to the movable section, the third pulley is attached to the fixed section, the ends of the flexible traction element are attached to the movable section and to the load carriage, the flexible traction element bends around the second, bottom third and top first pulleys (FR 2057287 A1 , 05/21/1971).

The disadvantage of this forklift is that when the carriage is raised to a height exceeding its stroke relative to the movable section, the carriage is not in its highest position relative to the movable section, which leads to a loss in the height of the load in the premises.

The technical effect of the proposal lies in the fact that it implements the mode of lifting the load "under the ceiling", i.e. this mode, in which the carriage is lifted to any (not higher than maximum) height that exceeds its stroke relative to the movable section, while the carriage reaches its highest position relative to the movable section, and, as a result, the loss of the height of the load in the premises is prevented.

This technical result is achieved by the fact that in the forklift of the loader containing the fixed and movable sections, the load carriage, a flexible traction element, made, for example, in the form of a chain, a limiter to move the flexible traction element, a lifting cylinder, and the movable section is connected to the stationary section with the possibility of its upward movement, the load carriage is connected to the movable section with the possibility of its upward movement, the first pulley is attached to the piston of the lifting hydraulic cylinder, to the movable section The second pulley is insulated, the third pulley or sprocket is attached to the fixed section, the ends of the flexible traction element are attached to the movable section and to the load carriage, the flexible traction element bends around the second pulley from above, the third pulley or sprocket from below and the first pulley from above, while the lifting cylinder and limiter flexible traction element attached to the fixed section, the limiter movement of the flexible traction element is configured to block the latter in any or some fixed positions.

Moreover, the limiter of movement of the flexible traction element may have a latch with a drive made with the possibility of moving the latch relative to the said sprocket, interacting with the chain and made with protrusions for interacting with the latch.

The graphic materials depict:

figure 1 - a forklift in its original position;

figure 2 - forklift in maximum freewheel;

figure 3 - a forklift in the mode of lifting the load to maximum height;

figure 4 - a forklift in the mode of lifting cargo to a maximum height when working in a room with a low ceiling;

figure 5 - forklift in the intermediate position of the mode of "lifting cargo under the ceiling";

6 is a forklift in the final position of the mode "lifting cargo under the ceiling";

7 and 8 - an embodiment of the limiter displacement of the flexible traction element in the off and on states.

The forklift contains a fixed 1 and a movable 2 sections (hereinafter referred to as HC 1 and PS 2), a load carriage 3 to which a load gripping device 4 (for example, forks) is attached, a lifting cylinder 5 (hereinafter referred to as a CPU) with a piston 6, a flexible traction element 7 (for example, a chain, hereinafter - GTE), pulleys 8, 9 and 10, a limiter for the movement of GTE 11 (hereinafter - the stop). The PS 2 moves up along the PS 1 using the rollers 12, the carriage 3 moves along the PS 2 using the rollers 13. In the lowermost position, the PS 2 is located on a support 14 mounted on the PS 1. The pulleys 8, 9 and 10 are located respectively on the piston 6, PS 2 and HC 1. One end of the GTE 7 is attached to the carriage 3, and the second to the PS 2.

The limiter 11 may, at the choice of the operator (driver of the loader), be in the off or on state. In the off state, the limiter 11 does not impede the movement of the GTE 7, and in the on state it blocks the possibility of moving relative to the HC 1 (at least in the direction in which the carriage 3 moves upwards) of the portion of the GTE 7 on which it acts. The impact can be carried out on any section of GTE 7 located between the pulleys 8 and 9.

An embodiment of the limiter 11 is shown in Fig.7 (in the off state) and 8 (in the on state). In this embodiment, the PGE 7 is made in the form of a chain, the pulley 10 is in the form of an asterisk to which one or more protrusions 15 are attached, with which the latch 16 can interact. The latch 16 drive can be mechanical, electrical, etc. In Figs. 7 and 8 for example, a retractor relay 17 of an electric drive is shown, the switch of which is located on the control panel of the loader. In the off state of the limiter 11, i.e. when applying power to the retractor relay 17, the latch 16 rises to the upper position, so the pulley 10 can rotate freely, and thus, there are no obstacles to moving the GTE 7. In the on state of the limiter 11, i.e. when removing power from the relay 17, the latch 16 under the action of its weight or spring (not shown) lowers to the lower position and, interacting with the protrusion 15, prevents the pulley 10 from rotating, at least in the direction in which the carriage 3 moves up ( in the diagram - clockwise), and, therefore, the movement of the above section of the GTE 7 relative to HC 1.

In other embodiments, the implementation of the limiter 11, the force of the retainer or brake pads can directly affect the GTE 7.

NS 1 can be attached to the body of the loader or be part of more complex (3-, 4-section or more) forklifts.

In the initial position (Fig. 1), the piston 6 is completely retracted into the CPU 5, the PS 2 is in its lowest position, relying on the support 14. The carriage 3 is also in its lowest position, being suspended from the stretched GTE 7.

The forklift can operate in three modes.

Freewheel mode (figure 2). In this mode, the limiter 11 is constantly off. After the high pressure liquid is supplied to the CPU 5, its piston 6 moves up and acts on the GTE 7 through the pulley 8, while the following forces act vertically on the PS 2:

- the weight P _PS PS 2 applied to its center of gravity and directed downward;

- two forces applied to the pulley 9 and directed downward, equal to each T, where T is the tension of the GTE 7. Neglecting friction in the pulleys 8, 9 and 10, we will assume that T is the same along the entire length of the GTE 7;

- the force T applied to the attachment point of GTE 7 to PS 2 and directed upward;

- the friction force F _TR.KAR between the PS 2 and the carriage 3, applied to the attachment point of the rollers 13 and directed upward;

- friction force F _TR.NS between PS 2 and HC 1, applied to the attachment point of the rollers 12 and directed downward;

- upward force F _OP reaction support 14.

As a result, force acts on PS 2

Given that

we get

those. the force F is directed downward, in magnitude no less than the weight of PS 2, and is countered by the reaction of the support F _OP . As a result, the PS 2 remains in its original position, located on the support 14.

The pulleys 9 and 10 function as fixed blocks, and the pulley 8 as a movable block, so the carriage 3 moves upward at a distance 2 times greater than the movement of the pulley 8, equal to the stroke 6, i.e. 2 A _CPU

When the condition is met

the carriage 3 will occupy its highest position relative to the PS 2 at the time of the full extension of the piston 6, i.e. under this condition, the maximum possible value (equal to A _CAR ) of the free wheeling is achieved for the given geometric dimensions of the elements of the forklift, or the free wheeling is full-sized.

When depressurizing the CPU 5, the carriage 3, under the influence of its weight (as well as the load gripping device 4 and the load, if any) moves down, and with it the piston 6 returns to its original position.

The mode of lifting cargo to a maximum height (figure 3). In this mode, the limiter 11 is turned on before lifting. At the same time, the GTE section 7 located between the pulleys 9 and 10 has a tension equal to (P _KAR + P _GZP + R _GR ), and the GTE section 7 located between the pulleys 8 and 10 is equal to (P _PS + P _KAR + R _GZP + P _GR ), i.e. the total moment of forces applied to the pulley 10 tends to rotate it in the direction in which the limiter 11 prevents this (clockwise in the drawing), and the GTE 7 actually splits into two independent sections, one of the ends of each of them being stationary relative to NA 1 as if these ends were attached to it. After applying pressure to the CPU 5, its piston 6 moves up and acts on the gas turbine engine 7 via a pulley 8, which performs the function of a movable unit. Therefore, the movement of the piston 6, and with it the pulley 8 upwards by the amount A of the _CPU, leads to the movement of the PS 2 upwards by a factor of two, i.e. 2 A _CPU . Together with PS 2, the pulley 9 attached to it, which now functions as a movable unit, moves up by the same amount. In this case, the carriage 3 moves upward by an amount twice as large as the movement of the pulley 9 or PS 2, i.e.

When the condition [4] is fulfilled, the carriage 3 will occupy its highest position relative to the PS 2 at the moment the piston 6 is fully extended, and the PS 2 itself will also rise upwards by 2 A of the _CPU , at which rigidity and strength of the forklift are still provided.

When the pressure in the CPU 5 is removed, the PS 2 under the influence of its weight moves down to the stop 14, the carriage 3 under the influence of its weight (as well as the load gripping device 4 and the load, if any) moves down, and with them the piston returns to its original position 6. After complete lowering of the PS 2 and its contact with the support 14, the limiter 11 can be turned off.

The mode of lifting cargo "under the ceiling". Let the forklift work indoors, and the distance from the top point of the PS 2 of the forklift to the ceiling is A _POT , where

In this case, in freewheeling mode, the load can be raised to a height of not more than H _CX equal to A _CAR . In the mode of lifting the cargo to the maximum height (Fig. 4), the PS 2 can move upward by a distance of no more than the value of A _POT , since at this moment, the upper part of PS 2 will come into contact with the ceiling. In this case, the stem 6 will be extended by half the amount equal to A _POT / 2. As a result, according to [5], the height to which the load in the room can be lifted to the maximum height is 2 A _POT .

As can be seen in figure 4, at this moment, the carriage 3 is not in the maximum position relative to the PS 2 (this position in the mode of lifting the load to the maximum height, it reaches only at the time of the maximum extension of the PS 2), which leads to a loss of the height of the load these conditions.

Lifting the load "under the ceiling" is carried out in two stages. First (Fig. 5), the carriage 3 is lifted with a load in freewheeling mode (limiter 11 is turned off) to a height H _KAP1 equal to

Piston 6 for the first stage will move up by

Since at the first stage the ascent is performed in the freewheel mode, SS 2 remains in place. Then, in the second stage, the limiter 11 includes a further lift (Fig.6) is carried out in the mode of lifting the load to maximum height. The piston 6 in the second stage moves up by

in this case, PS 2 moves upward by a factor of two, i.e. And _POT , and carriage 3 - by an amount 4 times larger, i.e.

Thus, in two stages PS 2 will move up by an amount equal to A _POT , i.e. reaches the ceiling, and the carriage 3 moves up relative to the floor by an amount

and with respect to PS 2, by a value of 2 A of the _CPU , and when the condition [4] is fulfilled, it will occupy the highest position relative to it. Thus, the loss of height of the load does not occur. The above is true if the design of the limiter 11 allows you to block the movement of GTE 7 in any of its position. If the design of the limiter 11 allows you to block the movement of GTE 7 only in some fixed positions (for example, N times for each revolution of the pulley 10, where N is the number of projections 15), then the loss of the lifting height of the load in this mode can, in the worst case, be TT / 2N, where D is the diameter of the pulley 10. By increasing N, one can reduce losses to an acceptable value.

Lowering the load also occurs in 2 stages. When the pressure in the CPU 5 is removed, the PS 2 moves down to the stop 14 under the influence of its weight, the carriage 3 moves down under the influence of its weight (as well as the load gripping device 4 and the load, if any), and the piston 6 also moves down with them. After the PS 2 is completely lowered and its contact with the support 14 (the carriage 3 at this moment will be at a height H _KAP1 ), the load on the part of the _{gas turbine} 7 connected with the PS 2 will be removed and the limiter 11 can be turned off. The carriage 3 lowers further, causing through GTE 7 the further lowering of the piston 6, which the limiter 11 does not interfere with, since it is turned off when the PS 2 contacts the support 14.

The load capacity of the forklift in the mode of lifting the load to the maximum height is

Where

m is the number of lifting cylinders,

R _CPU - working fluid pressure in the CPU 5,

S _CPU - the working cross-sectional area of the piston 6.

The coefficient 1/4 is present because in this mode, when moving by the value of h, the carriage 3 with the load moves by the value of 4h. In the freewheel mode with the same movement of the rod 6, the carriage 3 with the load moves by half as much as 2h, i.e. in the absence of other restrictions, the load capacity of the forklift in freewheel is 2 times greater than in the mode of lifting the load to the maximum height, which corresponds to the usual practice of storing heavier loads on the lower tiers, and lighter on the upper tiers.

Claims (2)

1. A forklift truck containing a fixed and movable section, a load carriage, a flexible traction element, made, for example, in the form of a chain, a limiter for moving the flexible traction element, a lifting cylinder, the movable section being connected to the stationary section with the possibility of its movement upward, the load carriage connected to the movable section with the possibility of its movement upward, the first pulley is attached to the piston of the lifting hydraulic cylinder, the second pulley is attached to the movable section, attached to the fixed section a third pulley or sprocket, the ends of the flexible traction element are attached to the movable section and to the carriage, the flexible traction element bends around the second pulley from above, the third pulley or sprocket from the bottom and the first pulley from above, while the lifting cylinder and the limiter of the flexible traction element are attached to the fixed section, characterized in that the limiter of movement of the flexible traction element is configured to block the latter in any or some fixed positions. 2. The forklift according to claim 1, characterized in that the limiter displacement of the flexible traction element has a latch with a drive made with the possibility of moving the latch relative to the sprocket, interacting with the chain and made with protrusions for interacting with the latch.

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