FR2673926A1 - Scissor-type lifting platform - Google Patents

Abstract

The invention relates to a scissor-type lifting platform controlled by an actuating cylinder articulated to a base. The platform according to the invention includes a calliper (8) mounted so that it can pivot on at least one of the arms (6) of the lowermost scissor element, the said calliper (8) including at least two branches (17, 18), for example in the shape of an L or U, one of the branches (17) of which is pivotally connected to the end (7b) of the actuating cylinder (7) located opposite that connected to the base (1) so that it can come to bear on a face, preferably a lower face, of one of the arms (6) of the lowermost scissor element, under the action of the actuating cylinder (7), and the other branch (18) of which is laid out to come to bear on one of the arms (9, 10) of the upper scissor element directly adjacent to the lowermost scissor element (6, 7), also under the action of the actuating cylinder (7). Application to lifting platforms.

Description

Scissor lift platform.

The present invention relates to a scissor lift platform comprising a base, a support platform which can be selectively lowered or raised relative to the base to respectively occupy a low position called transport or a high position called work, and a linking mechanism connecting the base and the support platform, the assembly being intended for lifting loads and / or personnel.

Work elevating platforms, including those of the scissor type are known. The oldest devices consisted of a double row of scissors arranged parallel and actuated separately or not by means of one or more hydraulic cylinders connected, for example, to a crank equipped at one of its ends with a roller and pivotally mounted on the pivot axis of one of the scissors, in accordance with the elevator described in EP-A-374500. However, these elevators had a number of drawbacks such as their size, which limited their use, and their cost.

To respond to this problem, manufacturers have turned to elevators comprising a single row of scissors, in accordance for example with the devices described in patents DE-A-3151031 and WO-A-90.01456. These elevators may, in accordance with DE-A-3151031, comprise a single scissor, the L-shaped arms of which are pivotally connected to one another and are actuated by means of a hydraulic cylinder connected to a lever arm disposed between said arms of the chisel. On the contrary, according to another embodiment in accordance with WO-A-90.01456, they can consist of several scissors pivotally connected to each other by means of a particularly simple articulation device. These devices, which overcome the problem of 'size, however still require the provision of a significant thrust at the start of the lifting operation of the platform, which requires the use of a powerful cylinder, therefore expensive.

One of the aims of the present invention is therefore to propose a scissor lift platform enabling the lifting operation to be carried out smoothly and without discontinuity while using a hydraulic actuator of low reduced power.

Another object of the invention is to propose an elevating platform of which the constituent elements are few so as to allow standardized and inexpensive manufacturing and rapid assembly of the assembly.

To this end, the invention relates to a scissor lift platform comprising a base, a support platform that can be selectively lowered or raised relative to the base to respectively occupy a low position called transport or a high position called work , a connecting mechanism connecting the base and the support platform, this connecting mechanism comprising at least two scissors, each scissor consisting of a first arm and a second arm interconnected by a pivot at a point located between their respective ends, generally in the middle, and the ends of which are pivotally connected to the ends of the arms of the adjacent chisel, one end of the first lower chisel arm being pivotally mounted and sliding on the base, one end of the second arm of the lowest chisel being pivotally mounted on the base, one end of the first arm of the highest chisel being rel pivoted and sliding on the platform, one end of the second highest scissor arm being pivotally connected to the platform, an actuating cylinder whose body is pivotally connected at one end to the base, characterized in that it comprises a stirrup mounted pivoting on at least one of the arms of the lowest chisel, said stirrup comprising at least two branches, for example in the form of L or U, one of the branches of which is connected pivoting at the end of the actuating member arranged opposite to that connected to the base so as to be able to come to bear on a face, preferably lower, of one of the arms of the lowest scissor under the action of the actuating cylinder, and the other branch of which is arranged to come to bear on one of the arms of the upper chisel directly adjacent to the lower chisel also under the action of the actuating cylinder.

Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows with reference to the appended schematic drawings, which description and drawings are given mainly by way of example. In these drawings
Figure 1 shows an overview of a flat
scissor lift form according to an example of
realization of the invention; Figure 2 shows a
front view of the lower part of the platform
lifting at the start of the lifting operation; figure 3
represents a front view of the lower part of the
lifting platform at the end of the lifting operation and the
Figure 4 shows a perspective view of the stirrup
swivel.

In accordance with FIGS. 1 to 3, the scissor lift platform comprises a base 1, a support or work platform 2 and a connection mechanism connecting the base 1 and the platform 2. This connection mechanism is constituted on the one hand by at least two scissors having a particular arrangement, on the other hand by a particular actuation device. The scissors which form the main constituent elements of the connection mechanism connecting the base 1 and the platform 2 both have two arms connected together by a pivot 3 which preferably interconnects the middle section of the first arm with the middle section of the second arm , it being understood that any other point situated between the respective ends of each of the scissor arms may be suitable for the positioning of the pivot 3. The ends of the arms constituting the scissors are pivotally connected to the ends of the arms of the adjacent scissor. Thus, in FIG. 1, the median chisel consisting of the arms 9 and 10 has ends respectively designated by 9a, 9b, 10a and 10b which are pivotally mounted on the ends 5b, 12a, 6b, 11a of the arms of the adjacent scissors , the lower chisel to the middle chisel being constituted by the arms 5 and 6, the upper chisel to the middle chisel being constituted by the arms il and 12.

In the example as shown in FIG. 1, the arms 5 and 6 form the lowest chisel of the lifting platform and the arms 11 and 12 form the highest chisel; this is why these scissors have arms whose certain ends are particular. The example shown in Figure i therefore shows a particularly simple structure of the lifting platform, but it is possible while remaining within the scope of the invention to have one or more scissors identical to the middle scissor, consisting of arms 9 and 10, between the scissors 4 and 13. This gives an elevating platform capable of working at particularly high heights.

The lowest and highest scissors have special configurations due to their respective connection with the base 1 and the working platform 2. The lowest 5.6, scissors of the lifting platform, is formed by the interconnection of the arms 5 and 6 at the pivot 3. The arm 5 has one end 5a connected to pivoting and sliding to the base 1 and one end 5b connected to the pivoting at the end of the arm of the adjacent chisel.

The end 5a is provided with a transverse axis 14, the end of which is equipped with a roller 15 guided in rotation inside a slide 16 arranged parallel to one of the edges of the base 1 in accordance with the FIG. 1. Thus, during the lifting operation, during which the arms of each scissor approach the vertical, the caster 15 rotates, allowing the end 5a to move in translation, in the direction of the arrow of Figure 1.

At the same time, the end 5a pivots around the axis 14.

The end 5a is therefore, thanks to this device, mounted at the same time pivoting and sliding on the base 1. Obviously, any other device can be used to obtain this pivoting and sliding movement.

The end 6a of the second arm 6 forming the lowest chisel is in turn only pivotally mounted on the base 1.

The ends iib and 12b of the arms 11 and 12 forming the highest chisel of the lifting platform are respectively mounted on the platform nacelle or nacelle 2, in a similar manner, at the ends 5a and 6a of the arms 5 and 6 forming the lowest scissor. Indeed, the end iîb of the arm 11 is pivotally and slidingly mounted on the platform 2 by means of a device which can be identical to that described in the case of the end 5a, while the end 12b is, in the same way as the end 6a, mounted only pivotally on the platform 2.

The lifting platform is also equipped with an actuating member 7 which can, in accordance with FIGS. 1 and 2, be constituted by a telescopic jack. The body of the jack 7 is connected at one of its ends 7a to the base 1 in a pivoting manner. The free end 7b of the rod of the jack is pivotally connected to a branch 17 of a stirrup 8 mounted pivoting about an axis 22 carried by at least one of the arms 5 or 6 of the lowest chisel. This axis 22 is preferably an axis crossing the arm 6 of the chisel 4 and disposed parallel to the pivot axis 3 interconnecting the arms 5 and 6 of the lowest chisel. This axis 22 is, in the example shown, arranged at the intersection of the branches of the L forming the stirrup 8.

The stirrup 8, which in the example shown has the shape of an L but which can also have the shape of a U, open or not, has a second branch 18 capable of coming to bear on one of the arms adjacent to the lowest scissor at the start of the lifting operation (Figure 2).

Thus, the operation of the stirrup 8 during the lifting operation is as follows in the lowered or transport position of the platform 2 (FIG. 2), the branch 18 of the stirrup 8 grips the sides of the arm 6 constituting one of the lower scissor arms.

Indeed, as can be seen in FIG. 4, the stirrup 8 consists of two flanges 20a and 20b arranged opposite one another and respectively affecting the shape of an L.

One of the branches of said L forming one of the flanges is connected, by means of a plate 21, to the branch of the other flange disposed opposite so as to provide a bearing surface. The other branches of the flanges separated from one another provide an empty space between them, the width of which is at least equal to the section of the arm 6 so that the arm 6, in the lowered position of the platform 2, is housed between the branches 20'a and 20'b of the flanges 20a and 20b forming the stirrup 8. It should be noted that the flanges 20a and 20b constituting the stirrup 8 also have two through holes 24 intended to receive axis 22.

Under the action of the jack 7, at the start of the lifting operation, the stirrup 8 pivots about its axis 22 so that its branch 18 comes to bear on one of the arms of the chisel adjacent to the most chisel lower, in this case the arm 9 in the example shown in Figure 2. This arm 9 is equipped with a shoe 23 which has at least one longitudinal guide groove (not shown) so that the branch 18 of the stirrup 8 and more particularly the end of this branch 18, slides inside this guide groove to a position designated by 26 in FIG. 2. At 26, the branch 18, if it continues to pivot around the axis 22 under the action of the jack 7, will no longer be supported on the arm 9, this is why, at this instant, the other branch of the stirrup, namely the branch 17, comes in support on the arm 6 of the lower chisel carrying the pivot axis 22 of the stirrup 8. The lifting operation always continues under the action of the jack 7, but thanks to the support existing between the surface 21 of the stirrup 8 and the face, preferably lower, of the arm 6 forming one of the arms of the lowest chisel.

Conversely, when it is desired to lower the platform 2, the support used in the first place is the support existing between the branch 17 of the stirrup 8 and the underside of the arm 6 then the support existing between the branch 18 bracket 8 and the underside of arm 9.

Note that, in the example shown in Figures 2 and 3, the arms which come into contact with the legs of the stirrup 8 are parallel arms (arms 6 and 9 in the drawing). However, it is possible that the branches of the stirrup 8 come to bear on two arms having a common articulation (arms 6 and 10 for example) but it will be necessary in this case to plan to mount the stirrup 8 or the shoe 23 offset from such that the branch 18 of the stirrup 8 is in the same plane as its support point (s) on the corresponding arm.

Thanks to the fact that during the lifting operation, the support points on the scissor arms are changed, it is possible to reduce the power required to start the lifting.

Finally, to allow a limitation of the number of parts necessary for the manufacture of the assembly, there are tie rods 27 (FIG. 1) which connect one of the ends of a first arm of a chisel to the end of the first arm of the adjacent chisel while also being fixed at the pivot 3 interconnecting two arms of the same chisel. Thus, in the example shown in FIG. 1, the tie rod 27 connects the end 6a of the arm 6 of the lowest chisel to the end 10a of the middle chisel passing through the pivot 3.

These tie rods 27 allow the use of hinge pins 3 of identical length regardless of their location on the chisel arm, that the chisel arm, whether in its middle ends, so as to thereby eliminate any risk of error. at the time of assembly.

Claims (9)

Claims.  Scissor lift platform comprising a base (1), a support platform (2) which can be selectively lowered or raised relative to the base (1) to respectively occupy a low position called transport or a high position called work, a connecting mechanism connecting the base (1) and the support platform (2), said connecting mechanism comprising at least two scissors, each scissor consisting of a first arm and a second arm interconnected by a pivot (3) at a point between their respective ends, generally in the middle, and the ends of which are pivotally connected to the ends of the arms of the adjacent chisel, one end (5a) of the first arm (5) of the lowest chisel being pivotally and slidingly mounted on the base (1), one end (6a) of the second arm (6) of the lower scissor being pivotally mounted on the base (7), one end (they) of the first arm ( 11) cisea u the highest being pivotally and slidingly connected on the platform (2), one end (12b) of the second arm (12) of the highest chisel being pivotally connected on the platform (2), a actuating cylinder (7) whose body is pivotally connected at one end (7a) to the base (1), characterized in that it comprises a stirrup (8) pivotally mounted on at least one of the arms ( 6) of the lowest chisel, said stirrup (8) comprising at least two branches (17,18), for example in the form of L or U of which one of the branches (17) is pivotally connected at the end (7b) of the actuating cylinder (7) arranged opposite to that connected to the base (1) so as to be able to come to bear on a face, preferably lower, of one of the arms (6) of the lower chisel under the action of the actuating cylinder (7), and the other branch (18) of which is arranged to come to bear on one of the arms (9, 10) of the upper chisel directly adjacent to the the lower chisel (6, 7) also under the action of the actuating cylinder (7). 2. Scissor lift platform according to claim 1, characterized in that the support of each of the branches (17, 18) of the stirrup (8) pivoting on the arms of the lowest scissor (6,7) and the upper chisel (9,10) directly adjacent to the latter is carried out in a predetermined order during the lifting operation of the platform (2). 3. lifting platform according to claim 2, characterized in that the branch (18) of the stirrup (8) which is mounted free comes to bear on one of the arms (9,10) of the chisel adjacent to the chisel the lowest (6.7) at the start of the lifting operation. 4. lifting platform according to claim 3, characterized in that said support is a mobile support (26) produced by sliding of said branch (18) of the stirrup (8) inside a guide groove formed in the vicinity of the chisel arm (9,10) adjacent to the lowest chisel (6,7) 5. lifting platform according to one of claims 1 to 4, characterized in that the branch (17) of the stirrup (8) pivoting articulated on the actuating member (1) does not bear on the '' one of the arms of the scissor (6,7) which is lower than from the moment when the other branch (18) of the stirrup (8) is no longer resting on the arm of the chisel (9,10 ) adjacent to the lowest scissor (6,7). 6. lifting platform according to one of claims 1 to 5, characterized in that the stirrup (8) is pivotally mounted about an axis (22) disposed substantially parallel to the axis of the pivot (3) interconnecting the arms (5,6) of the lower chisel. 7. lifting platform according to one of claims 1 to 6, characterized in that the stirrup (8) consists of two flanges (20a, 20b) arranged opposite one another and affecting the shape an L or a U, one of the branches of which forms one of the flanges and is connected by means of a plate (21) to the branch of the other flange disposed opposite so as to provide a bearing surface coming into contact with the lower scissor arm (6,7). 8. lifting platform according to one of claims 1 to 7, characterized in that the support points of the legs (17,18) of the stirrup (8) are arranged on parallel arms (6,9) of two adjacent scissors. 9. lifting platform according to one of claims 1 to 8, characterized in that tie rods (27) connect one end of an arm of a chisel to the end of the arm of the adjacent chisel through the pivot (3) interconnecting the arms of one of the two scissors.