EP1726560B1 - Scissor type lifting table - Google Patents

Abstract

Scissor-type lifting table (1) comprises a drive for pivoting the scissor parts (3, 4) and for lifting or lowering an upper frame (2). The drive has a traction mechanism (7) which is in contact with both scissor parts. The drive is in contact with a first contact point (10) arranged on the first scissor part (4), a second contact point (9) arranged on the second scissor part (3) and a third contact point (8) which is arranged on the first scissor part. The second contact part lies higher or lower than the first or third contact point when the upper frame is lowered. Preferred Features: The drive has a winding shaft (13) for winding the traction mechanism. The winding shaft is fixed to the first scissor part.

Description

The present invention relates to a scissor lift with a top frame and a scissors mechanism carrying the top frame, wherein the scissor mechanism has at least one scissor cross consisting of intersecting scissor members and the scissor members for raising or lowering the upper frame relative to each other are pivotable, wherein a drive for pivoting the scissor members to each other and is thus provided for raising or lowering the upper frame, which has a standing with two scissor members in contact traction means.

Scissor lift tables have long been known and are used in many ways. Frequently, the known scissor lift tables have two scissor crosses arranged parallel to one another, the scissor members of which can be pivoted relative to one another in order to raise or lower the upper frame connected to the scissors mechanism. In this arrangement, it is ensured that the plane formed by the upper frame is moved in parallel during pivoting of the scissor members. Most scissor lift tables are used in automotive technology but also in logistics, for example as a mechanical lift. Frequently, the scissor lift tables are provided with a hydraulic drive. However, the hydraulic drive requires a fairly high maintenance. Furthermore, such systems can cause damage to leaks, soiling of products and buildings. To avoid this, additional measures, e.g. the provision of a separator, be taken. In addition, increasingly stringent environmental regulations must be met, making the use of hydraulic drives less attractive.

Therefore, scissor lifting tables with a traction mechanism have already been proposed. For example, this describes DE 26 35 197 such a scissor lift. This scissor lift consists of two arranged by two between a lower and a platform covered with a top frame, formed by a pair of outer and inner shanks scissors, each connected to the lever ends via trusses and in each case two adjacent between lower and upper frame truss axes hinged to the lower and upper frame and are slidably mounted in guides of the upper and lower frame, wherein a drive unit causes the drive for the height adjustment of the scissor lift. To such a scissor lift with the help of a traction means, such. B. a drawstring or a chain drive To raise, a kind of winding element is generally provided on the lifting means of the upper frame, the traction means can be wound up. By winding the traction means a force is exerted on the scissor members of the scissors cross, so that they pivot relative to each other.

It is obvious that the force introduction in the deepest, i. lowered state of the scissor lift is not optimal. With the help of the traction means namely the lower ends of the two scissor members are acted upon with force. In the lowered state, however, the effective force component for erecting the scissor cross is very small, since the majority of the applied force is absorbed via the pivot connection.

This has the consequence that the drive must be dimensioned correspondingly larger. In addition, the traction means is initially very heavily loaded when lifting from the lowered position. In order to provide a sufficient effective force component for lifting the upper frame, these scissor lift tables often can not be completely lowered, which requires additional space.

In particular, in order to improve the Zugmittelgeometrie in the fully lowered state is in the DE 26 35 197 has already been proposed to provide two bearing blocks in a lower frame on which the traction means rests in the lowered state, in addition a Kettenführungsrad is provided on a scissor member, which comes to lie in the lowered state between the two bearing blocks. This has the consequence that in the lowered state when lifting initially in addition to the Kettenführungsrad a force is exerted on the relevant scissor member.

However, this embodiment has the disadvantage that on the one hand bearing blocks on the ground or a corresponding subframe must be provided and that the traction means leaves the bearing blocks relatively shortly after the lifting process, so that abruptly after leaving the bearing blocks a considerably larger force are applied to the traction means must to raise the scissor lift further.

Therefore is also in the DE 26 35 197 already an embodiment ( FIGS. 6 and 7 ), in which the Kettenführungsrad is attached to a projecting rod, which dips over a larger area between the bearing blocks. However, here a deep recess in the ground is necessary to accommodate the Kettenführungsrad in the lowered state. Even if it is ensured by this measure that the Kettenführungsrad During lifting a longer time remains in contact with the traction means, it will eventually lift off the traction means, resulting in an abrupt change in the introduction of force with the disadvantages mentioned above.

Furthermore, from the DE 103 14 967 a scissor lift known, in which the winding shaft is fixed to the ground or on the subframe and the traction means engages on the one hand at one end of a scissor member and on the other hand on an additionally provided projection. This projection is only in the lowered or almost lowered state of the scissor lift in contact with the traction means. Again, an additional force is exerted on the corresponding scissor member by the connection between the projection on the one hand and traction means on the other hand in the almost lowered state. However, as soon as the projection with the traction means disengages, a considerably higher force must be abruptly applied to continue the lifting operation. In addition, either a subframe is mandatory or the winding shaft must be fixed stationary on the ground, which greatly affects the mobility of the scissor lift.

The EP 1 375 410 describes a scissor lift with a top frame, which is supported by two lateral shears and guided in parallel, with a lifting device which has a drivable winding device, a traction means and a plurality of pulleys for the traction means. In this embodiment, all points of attack are in the lowered state of the upper frame at a height.

Based on this prior art, it is an object of the invention to provide a scissor lift of the type mentioned above, which is inexpensive to manufacture, is sufficiently mobile, d. H. can be moved as possible from one place to another with a few simple steps, and in which a smaller and above all more uniform force is sufficient for lifting the scissor lift.

According to the invention, this object is solved by the features of claim 1.

In the following it is assumed without restriction of generality that the second point of attack is higher than the first or third point of attack at least in the lowered state of the upper frame. However, it is understood that the same inventive effect can also be achieved if the second point of attack is at least in the lowered state of the upper frame lower than the first or third point of attack in principle, an embodiment the invention, in which the second point of attack at least in the lowered state of the upper frame is higher than the first or third point of attack is simply rotated by 180 ° and be placed upside down, so that the upper frame comes to lie down to get to an embodiment in which the second point of attack is at least in the lowered state of the upper frame lower than the first or third point of attack. Therefore, if it is assumed in the following that the second point of attack is higher than the first or third point of attack at least in the lowered state of the upper frame, it is understood that it could instead be lower.

The fact that the points are all attached to the scissor members, a total of a much more compact design is possible. In addition, now the scissor lift can be easily brought from one place to another, without having to be unscrewed any bearing blocks or winding shafts and remounted elsewhere. In addition, no recess must be provided in the ground.

Since when lifting the scissor lift all attack points, since they are located on the scissor members, move up - albeit to varying degrees -, the traction means remains longer in contact with the attack points, which means a better initiation of traction power. Also, when the traction means detaches from a point of attack, the transition is less abrupt.

In a further particularly preferred embodiment, the drive has a winding shaft for winding the traction means, wherein the winding shaft is preferably fastened to a scissor member, particularly preferably to the first scissor member. This measure also leads to improved mobility of the scissor lift. There is no additional attachment of the winding shaft necessary.

Furthermore, it is advantageous that, at least in the lowered state of the upper frame of the first point, the second point and the third point in the horizontal direction on the same side of the pivot axis about which the two scissor members are pivoted to each other, are arranged. As a result, the introduction of force is further improved because an optimal force effect is achieved by the guidance of the traction means at least in the lowered state.

In a particularly preferred embodiment, it is provided that the two longitudinal axes of the scissor members include an increase in the lifting of the upper frame opening angle, the second point at an opening angle less than 35 °, preferably less than 45 ° and more preferably less than 60 ° with the Traction means in engagement stands. In contrast to the isolated in the prior art proposed projections so here the second point remains during a large part of the lifting operation of the scissor lift in contact with the traction means. This has the advantage that no abrupt change in the application of force occurs.

In principle, it is best, according to the invention, if the second point of attack is almost during the entire lifting process, i. also in the fully raised position of the upper frame, remains in contact with the traction means, even if in this position, the second point of attack contributes to any significant improvement in the geometry of the force more.

Experiments have shown that with such an arrangement of the attack points a nearly continuous change of the force geometry can be achieved without abrupt jumps. The life of the traction device and the entire construction is thereby improved.

In a further particularly preferred embodiment, the traction means is fixed to a scissor member, preferably on the second scissor member. This measure leads to a more compact design and in particular to an increase in the mobility of the scissor lift.

Furthermore, it is advantageous if a deflection roller is provided on a scissor member on which the traction means abuts. Thus, for example, the winding shaft could be attached to the lower end of the first scissor member and the deflection roller may be arranged at the lower end of the second scissor member. The traction means would then, starting from the winding shaft of one scissor member, be guided via the deflection roller on the other scissor member to a fixed point on one of the scissor members. Now, if the winding shaft is actuated, this leads to the fact that the two ends of the different scissor members are moved toward each other by the winding of the traction means.

A further advantageous embodiment provides that the traction means, starting from the fixation on the scissor member, first over the third point of attack, then over the second point of attack, then over the first point of attack, then guided over the pulley and finally to the winding shaft. This arrangement has proven to be particularly effective for the introduction of force from the traction means on the scissors cross.

Although in principle the scissor lift can be realized with a single scissors cross, two scissor crosses or two double scissor crosses are preferably provided, which are arranged substantially parallel to each other. By this measure, the stability the upper frame significantly improved. Furthermore, even more scissor crosses can be provided behind or next to each other in order to realize even large scissor lift lengths or widths. The use of several scissor crosses over each other, ie the use of double scissor crosses or multi-scissor crosses, increases the achievable lifting heights.

According to the invention, it is possible to dispense with any lower frame and to place the lower end of a scissor member directly on the ground. Such a scissor lift can be easily transported from place to place, which is particularly advantageous if, for example, work should be carried out at a certain height on a longer building, because then any scaffolding could be dispensed with.

In another particularly preferred embodiment, a locking device is provided, which in the locked state, a pivoting of the scissor members to each other to lower the upper frame, prevented. By such a locking device, the train can be reduced to the traction means, which extends the life of the traction device.

Advantageously, the locking device is coupled to the traction means, so that when tearing the traction means, the locking device locks the scissor lift. If it comes due to improper handling of the scissor lift to damage the traction device, so that it ruptures during operation, the automatically locking locking device prevents a sudden "crashes" of the upper frame.

In a preferred embodiment, the locking device on a lever which is fixed to the one scissor member, and a detent having a plurality of detent positions, which is attached to the other scissor member, wherein the lever rests on the traction means in operation and upon tearing of the traction means gravity falls into a detent position of the catch.

Figur 1

eine Teilseitenansicht einer ersten Ausführungsform des erfindungsgemäßen Scherenhubtisches in der angehobenen Position,

Figur 2

eine Seitenansicht der Ausführungsform des Scherenhubtisches von Figur 1 in der abgesenkten Position,

Figur 3

eine Teilansicht von oben auf den Scherenhubtisch,

Figur 4

eine Teilseitenansicht des Scherenhubtisches in der angehobenen Position,

Figur 5

eine Seitenansicht des Scherenhubtisches in der abgesenkten Position,

Figur 6

eine Teilseitenansicht einer zweiten Ausführungsform des erfindungsgemäßen Scherenhubtisches in der angehobenen Position,

Figur 7

eine Seitenansicht der Ausführungsform des Scherenhubtisches von Figur 6 in der abgesenkten Position,

Figur 8

eine Teilansicht von oben auf den Scherenhubtisch von Figur 6,

Figur 9

eine Teilseitenansicht des Scherenhubtisches von Figur 6 in der angehobenen Position,

Figur 10

eine Seitenansicht des Scherenhubtisches von Figur 6 in der abgesenkten Position,

Figur 11

eine Teilseitenansicht einer dritten Ausführungsform des erfindungsgemäßen Scherenhubtisches in der angehobenen Position,

Figur 12

eine Seitenansicht der Ausführungsform des Scherenhubtisches von Figur 11 in der abgesenkten Position,

Figur 13

eine Teilansicht von oben auf den Scherenhubtisch von Figur 11,

Figur 14

eine Teilseitenansicht des Scherenhubtisches von Figur 11 in der angehobenen Position und

Figur 15

eine Seitenansicht des Scherenhubtisches von Figur 11 in der abgesenkten Position.

Further advantages and features of the present invention will become apparent from the following description of a preferred embodiment and the accompanying figures. Show it:

FIG. 1

1 is a partial side view of a first embodiment of the scissor lift according to the invention in the raised position,

FIG. 2

a side view of the embodiment of the scissor lift of FIG. 1 in the lowered position,

FIG. 3

a partial view from the top of the scissor lift,

FIG. 4

a partial side view of the scissor lift in the raised position,

FIG. 5

a side view of the scissor lift in the lowered position,

FIG. 6

a partial side view of a second embodiment of the invention Scherenhubtisches in the raised position,

FIG. 7

a side view of the embodiment of the scissor lift of FIG. 6 in the lowered position,

FIG. 8

a partial view from above of the scissor lift of FIG. 6 .

FIG. 9

a partial side view of the scissor lift of FIG. 6 in the raised position,

FIG. 10

a side view of the scissor lift of FIG. 6 in the lowered position,

FIG. 11

a partial side view of a third embodiment of the invention Scherenhubtisches in the raised position,

FIG. 12

a side view of the embodiment of the scissor lift of FIG. 11 in the lowered position,

FIG. 13

a partial view from above of the scissor lift of FIG. 11 .

FIG. 14

a partial side view of the scissor lift of FIG. 11 in the raised position and

FIG. 15

a side view of the scissor lift of FIG. 11 in the lowered position.

In FIG. 1 is a partial view of an embodiment of the scissor lift 1 shown. The scissor lift 1 has a top frame 2, which is supported by a scissors mechanism. The scissors mechanism consists of two scissor crosses, each having two scissor members 3, 4. The view shows only a pair of scissors. The second scissor member 3 is connected to a pivot axis 11 with the upper frame 2. The first scissor member 4 has at its the upper frame 2 end facing a roller 12, on the the upper frame 2 rests movably. The two scissor members 3, 4 are connected to each other at the pivot axis 6.

In FIG. 2 is a side view of the scissor lift 1 to recognize in the lowered state. It can be seen that at the lower end of the first scissor member 4, a winding shaft 13 is arranged. Furthermore, a deflection roller 14 is provided at the lower end of the second scissor member 3. The winding shaft 13 serves to receive a traction means. The traction means, which may for example consist of a drawstring, a rope or a chain, starting from the winding shaft 13 via a tension roller 15 first to the deflection roller 14. From there, the traction means initially reaches the first engagement member 4 connected to the first point of attack on the shaft or roller 10 is located. Thereafter, the traction means 7 reaches the roller 9 on the second scissor member 3, which provides the second point of application. Finally, the traction means reaches the roller 8 on the first scissor member 4, which provides the third point of application, and ends at the attachment 5, which provides a firm connection between traction means 7 on the one hand and scissor member 3 on the other. Now, starting from the in FIG. 2 shown position, the winding shaft 13 is driven, so that the traction means 7 is wound on the winding shaft 13, it is ensured by the arrangement of the rollers 8, 9, 10 and the three points of attack that connected to the first scissor member 4 rollers 8 and 10th which provide the first and third points of attack are raised.

If one waived the points of attack, as is partially the case in the state of the art, it would be, as one could say FIG. 2 can make clear, the power transmission very unfavorable, since only a small fraction of the applied by the winding shaft 13 to the traction means 7 force has an effective component that leads to an erection of the scissor lift 1. Without the three points of attack, therefore, the scissor lift 1 can not be lowered as far as in FIG. 2 is shown. The arrangement of the three shafts or rollers 8, 9 and 10 on one side of the pivot axis 6 ensures that upon actuation of the winding shaft 13, a large part of the applied force has an effective force component.

With the lifting of the scissor lift will eventually occur the situation in which the first point of attack with the traction means 7 is disengaged. Nevertheless, the second engagement point, which remains in engagement, ensures that there is improved power transmission. The two scissor members form an opening angle α, which increases with lifting of the scissor lift. Preferably, the second point or the roller 9 is up to a maximum opening angle with the traction means 7 in contact.

It will be understood that the points of engagement need not necessarily be provided by additional rollers or rollers. So it would be conceivable, for example, to dispense with the rollers 8 and 9. In this case, the guide roller 14 would provide the first point of application, the roller 10 the second point of attack and the attachment 5 the third point of application. It would also be possible to dispense with the roller 10 instead, so that the roller 9 provides the first, the roller 8 the second and the attachment 5, the third point of application.

The FIGS. 3 to 5 show partial views from above or from the side, which illustrate the course of the traction means 7.

Although a subframe is provided in the embodiment shown, it is clear that could be completely dispensed with by the inventive arrangement of winding shaft and the corresponding points on a lower frame. All forces remain within the scissor system and drive, traction means and the corresponding points of attack are attached only to the scissor links.

The scissor lift table can be used both for normal lifting operation and as an installation platform. The winding shaft 13 is preferably driven by an electric gear motor. The traction means is preferably formed by a belt. The various pulleys, rollers and support rollers are arranged to move substantially in the vertical direction so that an effective force component is achieved.

Furthermore, the arrangement of the points of attack or deflection rollers is such that, in principle, over almost the entire stroke range, the support via the second point of application or the deflection roller 9 is maintained.

It should be noted at this point that, of course, additional attack points can be provided to further reduce the effort. Furthermore, it is possible to arrange the drive or the winding shaft 13 also outside of the scissors mechanism. An alternative exemplary arrangement is shown in FIGS FIGS. 2 and 3 indicated by dashed lines on the left. This arrangement has the advantage that the drive can be easily maintained.

In the FIGS. 6 to 10 is a second embodiment of a scissor lift 1 'shown. As far as possible, the same reference numbers have been used for the same elements.

Unlike in the FIGS. 1 to 5 Shown embodiment, the attachment 5 of the traction means 7 is provided here on the roller 8. All other elements are identical to those in the FIGS. 1 to 5 shown embodiment.

In the FIGS. 11 to 15 3 shows a third embodiment of the scissor-type lifting table 1 ", where the same reference numbers have been used for the same elements as far as possible FIGS. 1 to 5 shown embodiment in that a locking device 16 to 20 is provided. The locking device consists of a lever 16 and a catch 20. The lever 16 is attached via the pivot axis 17 to the one scissor member 4. The lever 16 has a lever roller 19 and a lever tip 18. The lever roller 19 rests on the traction means 7. A catch 20 with different locking positions is arranged on the other scissor member 3. If there is a sudden tearing of the traction means 7, the lever 16 is no longer held due to the contact between the lever roller 19 on the one hand and the traction means 7 on the other hand in the raised position, but pivots in the direction of arrow due to gravity, so that the lever tip 18th engages in one of the locking positions of the catch 20 and thus provides a locking of the two scissor members to each other. The upper frame 2 can then not be lowered further.

It is understood that other embodiments are conceivable. Thus, it is for example possible to move the guide roller 9 in one of the embodiments shown upwards, so that it projects beyond the upper frame 2 in the lowered state of the scissor lift. As a result, the overall height of the scissor lift in the lowered state can be reduced.

In addition, it is possible to provide further points of application for the traction means, so that the traction means always alternately comes into contact with the first and the second scissor member.

Of course, a plurality of pairs of scissors members can be arranged side by side or one above the other.

LIST OF REFERENCE NUMBERS

1

Scissor

2

top frame

3.4

scissor members

5

attachment

6

swivel axis

7

traction means

8, 9, 10

Roll / wave

11

swivel axis

12

role

13

winding shaft

14

idler pulley

15

idler

16

lever

17

Lever pivot axis

18

lever tip

19

lever

20

notch

Claims (12)

1. A scissor lifting table (1) comprising an upper frame (2) and a scissor mechanism carrying the upper frame (2), wherein the scissor mechanism has at least one scissor cross comprising mutually crossing scissor members (3, 4) and the scissor members (3, 4) are pivotable relative to each other about a pivot axis (6) for raising or lowering the upper frame (2), wherein there is provided a drive for pivoting the scissor members (3, 4) relative to each other and thus for raising or lowering the upper frame (2), which has a pulling means (7) in contact with both scissor members (3, 4), and the pulling means (7) is in contact at least in the lowered condition of the upper frame (2) in succession with a first engagement point (10) arranged on the first scissor member (4), with a second engagement point (9) arranged on the second scissor member (3) and a third engagement point (8) arranged on the first scissor member (4), characterised in that at least in the lowered condition of the upper frame (2) the second engagement point (9) is higher or lower than the first or third engagement point (8, 10), wherein all engagement point move to differing degrees upon raising of the scissor lifting table.
2. A scissor lifting table (1) according to claim 1 characterised in that the drive has a winding shaft (13) for winding on the pulling means (7), wherein the winding shaft (13) is fixed preferably to a scissor member (3, 4), particularly preferably to the first scissor member (4).
3. A scissor lifting table (1) according to claim 1 or claim 2 characterised in that at least in the lowered condition of the upper frame (2) the first engagement point, the second engagement point and the third engagement point are arranged on the same side of the pivot axis (6) in the horizontal direction.
4. A scissor lifting table (1) according to one of claims 1 to 3 characterised in that the two longitudinal axes of the scissor members (3, 4) include an opening angle (α) increasing when the upper frame (2) is raised, wherein the second engagement point is in engagement with the pulling means (7) at an opening angle (α) of less than 35°, preferably less than 45° and particularly preferably less than 60°.
5. A scissor lifting table (1) according to one of claims 1 to 4 characterised in that the pulling means (7) is fixed to a scissor member (3, 4), preferably to the second scissor member (3).
6. A scissor lifting table (1) according to one of claims 1 to 5 characterised in that provided on a scissor member (3, 4) is a direction-changing roller (14) against which the pulling means (7) bears.
7. A scissor lifting table (1) according to claim 5 or claim 6 characterised in that starting from the fixing to the scissor member (3, 4) the pulling means (7) is firstly passed over the third engagement point, then over the second engagement point, the over the first engagement point and then over the direction-changing roller (14) to the winding shaft (13).
8. A scissor lifting table (1) according to one of claims 1 to 7 characterised in that there are provided two scissor crosses arranged in substantially mutually parallel relationship.
9. A scissor lifting table (1) according to one of claims 1 to 8 characterised in that no lower frame is provided but the lower end of the one scissor member (3, 4) stands directly on the ground.
10. A scissor lifting table (1) according to one of claims 1 to 9 characterised in that there is provided an arresting device which in the arrested condition prevents pivotal movement of the scissor members relative to each other to lower the upper frame.
11. A scissor lifting table (1) according to claim 10 characterised in that the arresting device is coupled to the pulling means so that when the pulling means tears the arresting device arrests the scissor lifting table.
12. A scissor lifting table (1) according to claim 11 characterised in that the arresting device has a lever fixed to the one scissor member and a latching means having a plurality of latching positions and fixed to the other scissor member, wherein in operation the lever bears against the pulling means and when the pulling means tears drops under the force of gravity into a latching position of the latching means.

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