DE2930316C2 - Telescopic mast for forklifts - Google Patents

Description

: 5

is mobile. and further, the extensible piston rod 25 bears loads. The same goes for the other

the mast lift cylinder piston assembly is connected to an extending mast. characterized, that the piston rod (11) of the free stroke cylinder piston assembly (3, 3 ') before reaching the maximum possible extension length with a Stop (18, 19, 27) comes into contact with a mast part and together with her up to her end the piston rod (? 5) of the t'.ast stroke cylinder piston assembly (2) int parallel drive is extendable.

2. Lifting frame according to claim ·; h 1, characterized in that the maximum possible extension length of the piston rod (11) of the Frcihub -ylindcrkolbcnanordnung (3,3 ') is limited by a stop (21, 2Y) which is between the load receiving device State of the art.

The invention is based on the object in transition from the free lift to the telescoping of the mast a largely uniform speed to achieve a smooth transition.

This object is achieved according to the invention in that the piston rod of the free stroke cylinder piston arrangement before reaching the maximum possible extension length with a stop on a mast part in

J5 position comes and together with it until the end of its stroke the piston rod of the master stroke cylinder piston arrangement can be extended in parallel operation. Through this parallel operation there is an overlap in the transition between the two drive walls and compensation

tel (6) and its associated extension mast (5) 40 due to the merger of the two cylinders, see above

is arranged. that thereby a steady speed before

3. Mast according to claim I or 2. at wcl- all without overloading the drives, maintained

brazen a standing mast, a middle and an intimate one and a smooth transition with an even

Extending mast are arranged and the free lift cylinder speed is reached. This results in the

the piston arrangement at the base of the standing mast 45 transition area a partial relief of the drive

is provided, characterized in that the counter bearing (18, 19) on the central or inner extending mast (4,5) is arranged.

4. Lifting frame according to one of claims 1-3, at which the free lift cylinder piston arrangement is arranged hanging on an extendable mast part, and the top of this extension part is the base for this Frcihub cylinder piston arrangement forms, characterized in that the Gegenhigcr (27) on Standing mast (1) is arranged.

The invention relates to a telescopic mast for w> Forklifts, with a sense of purpose and at least one Extension mast. to your a load handling device and can be moved in the Frcihub by a lifting trowel. with two cylinder pulley arrangements, one of which a free lift cylinder piston assembly eiw; i with half hi Cylinder length with respect to the masts and the other a mast lift cylinder piston assembly with substantially the length of the masts corresponding cylinder bc. because the forces that occur in this area are from both cylinder piston arrangements can be taken over together, but then effective through the HubUetten or cold guides for an essentially uniform extension speed the load handling equipment is provided.

The maximum possible extension length of the piston rod of the free lift cylinder piston arrangement is particularly advantageous limited by a stop.

Yi which / wipe the load handling device and the extension arm assigned to it is arranged.

In another version of the mast, at which a standing, a middle and an inner one Ausfahrniiisi are disordered and the Frcihub-cylinder piston arrangement is provided at the base of the stand mast. see a particularly advantageous embodiment in front of the counterpart on the middle or inner Ausfahrmasi is arranged. But also when used deep inside stop in the Frcihub cylinder piston becomes the !! clashing of the trowels and parts of the system is not larger than groove / load and I-ügLMigcwicht require.

In a further expedient embodiment. in

which the Frcihub cylinder piston assembly on a Ausfahrpiastteil is arranged hanging and the upper end of this Ausfahrmastteüs the base for this Forms free lift cylinder piston assembly, the counter bearing is arranged on Siandmasi. If the retractable Abutment of the free stroke cylinder piston assembly cooperates with a Gegencniager, which on the inner Extending mast is arranged there is the advantage that the two cylinder-piston assemblies in the overlapping operation escaping forces act on the middle and inner extending mast.

An embodiment is reserved in which the free lift cylinder piston arrangement is attached to an extending mast part is arranged hanging and the upper end of this Ausfahrmastteiles the base for this free lift cylinder piston assembly forms to which the lifting chain is attached with its end remote from the load handling device is, wherein the counter bearing is arranged at the lower end of an adjacent mast part. It forms the free lift cylinder piston assembly practically Spreading means in overlapping operation. This is also with a very simple chain guide in one advantageous arrangement a largely uniform and smooth movement of the load handling device, even in the transition from the special free lift to the extension reached with the telescoping mast.

The invention is explained below using schematically illustrated exemplary embodiments that are only Specify the function, with the reservation that cylinder / piston arrangements are central and also nested or advantageously on the side in the case of free-lift scaffolding, possibly nested or separated, to arrange. The mast rails or guide means of the mutually movable parts correspond to the known designs and are not shown in more detail. Show in the drawing

Fig. La-d a principle view for a three-pole mast with free lift in various functional positions;

Figures 2a-d show another embodiment of a triple mask in the various functional positions;

3a-d shows a corresponding representation of various Functional positions of a double mast.

The connected parts have been assigned to one another Mast rails or guide rollers that run in these rails, which are known per se, and the insofar are not described in more detail.

It is common to all of the embodiments shown that a mast lift cylinder piston arrangement is present. whose cylinder 20 has substantially the same length as the mast rails, not shown, on which either the load handling device 6 can be raised, or between masts that can be extended to one another 4.5 are arranged. The free lift cylinder piston assembly 3 has a cylinder 13, which in comparison to have essentially half the length.

Both cylinders 13 and 20 are connected in parallel by a line 29 in which a pressure relief valve 30 is arranged in front of a pressure medium source or a pump assembly 31. In both cylinders, pressure is applied introduced with the same pressure. This connection is shown only once in each figure.

The two cylinder piston assemblies 2, 3 travel due to different dimensions of their effective Cross-sections or due to their arrangement in the assigned masts. or due to the leadership of Hub or SynehronketVn depending on the occurring forces or loads, one after the other to first perform the free lift and then the mast, d. H. at least one telescopic mast, extend, with the process in the opposite direction and when the mast is retracted takes place in reverse order.

In Figs. 1 and 2, like parts are like Reference numerals denoted. On a standing mast 1 is a mast lift cylinder piston assembly 2, whose Cylinder 20 is substantially the same length as the masts, and a Frcihub cylinder piston assembly 3 arranged, the cylinder 13 has substantially half the length of the masts. Each mast has a middle extendable mast 4 and an inner extendable mast 5. on which a load handling device 6, for example a normal sledge with a load carrying fork, is guided vertically.

The load handling device 6 is suspended from a lifting chain 7, which via guide means 3, for example a RoHe, at the upper end of the inner extendable mast 5 and from there via guide means 9, for example a roller, to the lower end of the extendable mast and from there via guide means 10, for example, a roller on the extendable end of the piston rod 11 of the free lift cylinder piston arrangement to

r> ner fasteners 12 is guided. which are in the example on cylinder 13 of the free lift cylinder piston assembly is located. This point could also be provided on the standing mast 1, since the free lift cylinder piston arrangement 3 is firmly arranged on this.

Furthermore, the designs according to FIGS. I and 2 have a so-called for the triple masts shown Synchronous chain 14, which is attached at 15 at the lower end of the inner extendable mast 5 and via guide means 16, in particular a role, at the upper end of the central extendable mast 4 also to a point, for example 12. are guided and fixed in their area, this point being firmly assigned to the standing mast 1 is.

According to FIGS. 1 and 2, a first abutment 17, in particular above the guide means 10, is arranged at the upper extendable end of the piston rod 11 of the free-lift cylinder piston arrangement 3. The versions according to the Fig.! and 2 differ in that according to FIG. 1 for the abutment 17 a counter-bearing 18 on the middle extension mast 4 and. According to Figure 2, a Gegencniager 19 is arranged on the inner extension mast 5. The abutment 17 strikes against this abutment. when the mast is extended. In the course of operation, the counter bearings 18 and 19 then lift off from the counter bearing 17 again.
To assess the function, the following applies:

Weight of the inner extension mast 5;

Weight of the middle extension mast 4:
Force in the lifting chain 7:

Then:

Force on the Frcihub cylinder3:
Force on the mast lifting cylinder cr2:

IN THE

MM F.

2F

2F + 2IM

+ MM.

lieide cylinders 13, 20 have in relation to those in them guided piston equally effective cross-sections. Due to the weight distribution mentioned above, to which

Always take into account that they are also under stress the load suspension device through a Las! remains echoed, Since this load is superimposed on the fundamental given values, the free lift cylinder piston assembly moves first 3 until the counter-stop 18 according to FIG. 1 on the central extension mast part or the Gcgcnan · 19 on Ausfahrmasi according to Fig. 19. 2 is reached. This position is shown in FIG. I b and 2b shown. Included the load handling device is especially in free lift up to close to the upper limit of its lifting distance on the inner in Extending mast 5 moved. As a result of the translation of the lifting chain 7 moved due to its described course the load handling device 6 moves at twice the speed on the extending mast 5, which initially remains at the bottom compared to the extension speed r. the piston rod II of the .Somlerfreihub cylinder piston assembly 3. When the first abutment 17 has reached the counter stop 18 or 19. does the free

by the resulting additional load with the mast: ο hub-cylinder piston assembly 2 together. This initiates a telescopic movement of the mast, initially the inner extension mast 5 as a result of the leadership with the Celts Translation twice as fast and the l.asinaufaufnahme-> -. medium 6 would move up four times as fast as the middle extending mast 4, if not in this one Transition area the two cylinders 13, 20 of the Frcihub cylinder-piston arrangement 3 and the mast lift cylinder piston assembly 2 would be fed in parallel. In- jo insofar as the resulting lifting speed of the load handling device 6 remains the same, because the constant The effective amount of pressure added is distributed between the two cylinders and the previous one with the same effective areas Lifting speed of the free lift cylinder piston> arrangement 3 is halved. In the case of telescoping, which is now taking place under these conditions, both act Cylinder piston assemblies share the forces

2 F + 2 F + 2 IM + MM = 4 / · '+ 2 IM + MM «, so each cylinder that lallte. These are:

22 the pressure medium is now fully applied to the mast lift / yliulerkolbenanorclnung so that. except for the previously described stroke of the extendable mast 5 by the short distance shown, the Teleskopbcwegung continued will. The load suspension device 6 has reached the previously described abutment 21 or 22 reached its highest position on the inner extension mast 5. The Tcleskophub is then carried out by means of the described Synchroiikcttc 14, wherein Simultaneously with the lift of the inner extendable mast 5 and the middle extendable mast 4, they are moved apart in the vertical direction will. The extension speed of the mast lift cylinder piston assembly 2 is doubled compared to the previous state because the Irciluib cylinder piston assembly is in its extended position Position remains. This, in conjunction with the trowel guides, ensures that the load handling device f> almost at the same speed up to now

as until now

above

will.

This force is in accordance with the force distribution given above on the free lift cylinder 13 and the Mast lift cylinder 20 between the two forces for which the cylinder piston assemblies 2 and 3 are each provided can be seen, so * Jass in the transition area there is a particularly large jointly effective cross-section and a smooth transition in operation is secured, in which the load suspension means 6 in its upper position on the inner extending mast 5 trans- v> is posed. When this upper position is reached (shown in Fig. Ic and 2c). becomes a second abutment closed. This second abutment is either in the version 21 between the inner extending mast 5 and the load handling device 6 arranged or in the mi Inside of the cylinder 13 of the special linear stroke cylinder piston arrangement 3. where this inner abutment is designated by 22. These / wide abutments 21,22 prevent Another extension of the Sonderfrcihiib-Zylinderkoibenanordnu.ng 3. When this / wide abutment hl is closed. the inner extension mast 5 is also off raised to its lower position. By closing the / wide abutment 21 or When using the stop 21, the chains are over what is required by the payload and dead weight Mali also burdened, and / was by the force that is created by a pressure on which an overpressure valve 30 is set in an associated hydraulic system for the pressure medium. When the inner stop 22 is used, the force on the Celts and other parts of the system is not greater uls results from the payload and dead weight. The latter version is therefore preferred.

If according to Fig. I the Sonderfrcihub-cylinder piston arrangement 3 and the mast-lift cylinder piston assembly 2 act on the same GegeneMager 18 is an absolutely parallel load at the transition between the positions according to Fig. Ib and c guaranteed. This The counter-bearing also forms the connection between the piston rod 25 of the mast lift cylinder piston arrangement 2 to the middle extension mast 4.

If according to FIG. 2 the abutment 17 with the abutment 19 cooperates on the inner extending mast 5, while the mast lifting cylinder piston assembly 2 with a counter-bearing 23 on the middle Ausfahrmasi 4 is in connection, result in the special free stroke cylinder piston arrangement 3 Forces from the load handling device β and the inner extension dimension 5. while the Masihub cylinder piston arrangement 2 via the synchronizer 14 takes over the weight of both extending masts.

The schematic execution in side view does not exclude the rest. that all cylinder piston assemblies split in pairs and on both sides of the mast, which is then designed like a portal, are arranged.

F i g. 3 shows a double mast that manages without a synchronous chain. In the manner already described it is a load handling device 6 guided via a lifting chain 7 on the inner extendable mast 5, which in turn on the Standmasi 1 is guided vertically. The mast lift cylinder piston assembly is on this stationary mast 1 2 supported below, while the Frcihub cylinder piston assembly 3 'is provided in this embodiment hanging isi and arranged with its cylinder 13 on an upper abutment 24 of the extendable mast serving as a base is. on which the piston rod 25 of the full-stroke cylinder-piston arrangement 2 also engages. It is the lifting chain 7 according to the previous embodiments via guide means 8 or a roller on upper F.ende of the inner extension mast 5 and a corresponding guide means 26 or a role on the

downwardly directed piston rod II of the I-Yeihiib /. ylinder piston arrangement 3 'to the extendable counter bearing 24 serving as the basis for the special free-stroke cylinder piston arrangement 3'. In this embodiment, too, both cylinder piston assemblies move. openings 2, 3 '/ by lifting the load handling device 6. /. by part individually / by part together, out and for lowering ^: n reverse order on. The lifting chain 7 is only loaded to the extent that it results from the payload and its own weight. In this embodiment, too, the cylinder 20 of the mast lift cylinder piston assembly 2 is about as long as the mast rails and is supported in the stationary mast, while the cylinder 13 of the special free lift cylinder piston assembly 3 'is about half the length, but its cylinder is at the upper end of the inside rcn extension mast 5 is attached. The piston rod II extends downwards. With this version the following force distribution results:

Force in the lifting chain ?: / ■ '_> o

Then force on the free lift cylinder 3 ': 2 1' Force on the mast lift cylinder 2: F + IM,

where the terms are explained above.

Is in this embodiment, Hubkettenführung shown also in view of the 2 ^r>, the effective cross section of the free lift cylinder piston arrangement 3 'twice as large as that of the mast lift cylinder piston arrangement.

Both cylinders 13, 20 of the cylinder piston arrangements 2, 3 are also connected in parallel in this embodiment. Due to the forces occurring and the effective cross-sections, the special free stroke cylinder piston arrangement 3 'first moves out, so that the load-bearing means 6 is brought into the position shown in FIG. 3b. In this place, the abutment 17 'is to be Gc cheek displaced 27 at the base of the fixed mast part I. During the transition from the position of F i g. 3b in position 3c, both cylinder piston assemblies 2, 3 are acted upon until either an outer abutment 21 'is reached between the load-bearing means 6 and the inner extending mast 5, or an inner stop 22' in the Sonderfrcihub cylinder piston assembly 3 '. When performing this telescopic stroke, the force is distributed across both cylinders:

45 2F + F + IM ~ 3F + IM

half per cylinder: 3 IM

2 ^{f +} T

As a result of the larger effective cross-sectional area of the Sonderfrcihub cylinder piston arrangement 3 ' in the lifting chain guide shown, the reduction in speed of the load-bearing means 6 resulting from the cylinder-piston arrangements between the positions in FIGS. 3b and c compensated by the fact that the extension mast 5 is raised at the same time. In further operation, the extending mast 5 then moves with the load-bearing M) at a standstill in relation to it. medium 6, that is, the absence of a movement transmission between the load handling device 6 and the extending mast 5, essentially at the same speed upwards as before, when the extendable mast 5 is raised by the mast lift cylinder piston assembly 2 alone. bS

In addition 6 sheets of drawings

Claims (1)

Patent claims: 1. Telescopic mast for forklifts, with a standing mast and at least one extending mast, on which a load handling device is guided and can be moved in free lift by a lifting chain, with two Cylinder piston assemblies, one of which is a free stroke cylinder piston assembly about halfway through Cylinder length with respect to the masts and the other a mast lift cylinder piston assembly with substantially the length of the masts corresponding to the cylinder length, the lifting chain from the load handling device via guide means arranged on the respective extension mast and via guide means on the extendible piston rod of the free lift cylinder piston assembly to the base of the free lift cylinder piston assembly is led. Both cylinders are joined together and their pistons can be extended one after the other as a result of the various loads s »9d, with the mast lift cylinder piston arrangement for telescoping the mast according to Reaching the highest position of the load handling equipment in the assigned mast rails alone is sufficient is. wherein the lifting chain from the load handling device is arranged on the respective extending mast Guide means and via guide means on the extendable piston rod of the free lift cylinder piston assembly is guided to the base of the free lift cylinder piston assembly, both cylinders joined together are and their pistons can be extended one after the other as a result of the various loads, the Mast lift cylinder piston assembly for telescoping the mast after reaching the highest Position of the load handling equipment in the assigned mast rails can be extended alone. and also the retractable one Piston rod of the Maslhub cylinder piston order is connected to an extending mast. F. such a design according to GB-PS 12 87 928 and also a design according to DE-PS 10 24 432 have the disadvantage that shocks occur during the transition from free lift to telescoping of the mast, because a successive use of the two cylinder piston arrangements takes place and also during use The second cylinder-piston arrangement is affected by signs of release or throwing off by drive components. According to GB-PS 12 87 928, when the laser slide lift changes to the extension of the mast, different IU