WO2018051375A1

WO2018051375A1 - Carrying stairs with a system to lock the wheels

Info

Publication number: WO2018051375A1
Application number: PCT/IT2016/000212
Authority: WO
Inventors: Filippo SONCIN
Original assignee: Soncin Filippo
Priority date: 2016-09-15
Filing date: 2016-09-15
Publication date: 2018-03-22

Abstract

Such invention concerns a ladder (1) of the transportable type comprising: A frame (2, 3, 4) suitable for allowing the arrangement of one or more supporting surfaces (6) through which a user can reach one or more different heights from the ground; At least a wheel (19) forming a support point to the ground, said wheel being suitable for allowing the movement of the ladder; A braking device (5, 10, 15, 20) to lock the wheels. According to the invention, such braking device comprises a braking body (5') cooperating with said wheel, said wheel being arranged in such a manner to result movable between an extended position, wherein it emerges respect to the braking body, contacting in use the ground, and a retracted position wherein, in use, the braking body contacts the ground exerting a braking action and wherein, further, pushing means (10) are comprised and configured in such a manner to maintain said wheel in said extended position for force values that act on it, in the direction of movement towards the retracted position, that are below to a predetermined threshold value and allow a movement of the wheel towards the retracted position, when reached or exceeded this threshold force value, in such a manner that when the wheel is retracting, the braking body moves to contact the ground.

Description

TITLE

CARRYING STAIRS WITH A SYSTEM TO LOCK THE WHEELS Technical field

The present invention refers to the technical field of the transportable ladders.

In particular, the invention refers to an innovative ladder, equipped with wheels, which results to be easily transportable and safer and more functional at the same time .

Background art

Transportable ladders have been known for a very long time. They have a wide use both in the domestic field and in working and professional field.

There are many types of transportable ladders, that have different materials, weight, resistances and sizes.

Generally, a transportable ladder is constituted by a frame which includes a couple of parallel bars mutually fixed and hinged to a second couple of parallel bars equipped with steps. The two mentioned couples of bars are hinged each other in such a way to open and close as scissors. The two couples of bars form the stable support to the ground at their extremity, in such a way to create four support points to the ground to make the ladder stable when they are opened. Furthermore, they are equipped with a leverage, that is automatically activated in response to the open or closed position of the bars, in such a manner that, in the open position, such leverage moves the support loading beds forming the steps. In this way, in the open position, the ladder is conformed in such a manner that results stable to the ground and with such loading beds overlapped one to the other and in horizontal position in such a manner that each one constitutes a step .

In closed position, a couple of bars approaches to the other and, at the same time, such loading beds fold up in a vertical closing position (that is more or less parallel to such couples of bars) , in such a manner that they minimize obstructions.

This type of technology has been known for a long time by now and numerous types of ladders of this aspect have been sold for a long time by now.

In another simpler case the steps are not rotating but instead fixed in horizontal position and so said leverage is not provided.

Other types of ladders are structurally simpler and are of the traditional type, that is they lean to a wall and are formed by superimposed diagonal beams that form the steps.

In all said cases, such types of ladders have the characteristic of having such weights and sizes in such a manner that a user can carry them manually on site to work at heights as required.

A critical element of every ladder is clearly its stability as, in the working position, it has to result fixed and stable to avoid the risk of falling of the user. At the same time, the ladder, in the working position, has also to be easily carried from a place to another one, without the necessity of closing and raising it, for example without necessarily closing it but leaving it in the configuration of use. For that purpose there are countless different types of ladder that are equipped with at least a couple of wheels in order to move them easily without necessarily closing and raising them.

For example, at the following internet address: https : //www. google . it/search?q=scale+con+ruote&biw=l

920&bih=963&tbm=isch&tbo=u&source=univ&sa=X&sqi=2&ved=0ahU

KEwily7nn4aTOAhXGshQKHW14CvQQsAQITw&dpr=l are visible images of ladders or working loading beds that are normally on sale and are equipped with wheels for an easy movement.

The wheels are clearly equipped with a braking system that prevents them from rotating in such a way that, during the use of said ladder by the worker, there is no risk of accidental movements that may cause the fall of the worker.

A technical problem that exists with said type of ladders, or also loading beds is that the wheels blocking system is particularly complex and additionally, it requires a voluntary activation by the user before climbing the ladder.

In that case, if the user, forgets to put the block of the wheels before using the ladder, the movement of the ladder can occur and cause a heavy and dangerous fall.

Disclosure of invention

It is therefore the aim of the present invention to provide a ladder of the transportable type, which solves said technical inconveniences.

In particular, it is the aim of the present invention to provide a ladder equipped with wheels for its portability but that, at the same time, it results fixed and stable during its use without necessarily requiring a manual insertion of a brake of the wheels before using the same ladder.

These and other aims are reached with the present ladder of the transportable type, as per claim 1.

The said ladder comprises:

A frame (2, 3, 4) usable for holding one or more loading beds (6), for example mobile or fixed, through which a user can reach one or more different heights from the ground;

At least a wheel (19), preferably linked to the frame, thus forming a support point to the ground, said wheel being suitable for allowing the movement of the ladder;

A braking device (5, 10, 15, 20) for blocking the ladder, for example operating by slithering to the ground.

According to the invention, such braking device consists of a braking body (5') cooperating with the wheel. The wheel results mobile between an extended position, wherein it emerges from the said braking body laying in use to the ground, and a retracted position wherein it retracts to the same level or behind the braking body and in such a manner that the braking body in use contacts the ground.

Pushing means (10) are further comprised and configured in such a manner to maintain said wheel in said extended position for force values that act on it, in the direction of movement towards the retracted position, that are below a predetermined threshold value and allow a movement of the wheel towards the retracted position, when reached or exceeded this threshold force value, in such a manner that when the wheel is retracting, the braking body moves to contact the ground.

In such way, when the wheel is in extended position, the wheel emerges and comes out from the braking body contacting the ground and carrying out its purpose. When instead the wheels retracts from the braking body, as a matter of the fact the braking body contacts the ground more than the wheel that can only touch lightly the ground, preventing the wheel from carrying out its purpose and carrying out a general blocking action to the ladder, prevailing to the action of the wheel.

In order to control the correct position of the braking device and therefore of the wheel, such pushing devices are comprised, configured in such a manner that they maintain said wheel in the extended position for the force values that act on it, in the direction movement towards the lifted position, that are below a predetermined threshold value and allow a movement of the wheel towards the retracted position, when reached or exceeded this threshold force value.

It is therefore enough to calibrate such pushing means in such a manner that, when there is no worker on the ladder, and so only the weight of the said ladder acts on the wheel as a reaction of the ground (or in any case a more restrained weight below an average weight of a person operates) , so the wheels maintain such extended position in contact to the ground and operating normally. In this way, the ladder is therefore easily transportable by dragging it through the wheel/s from a position to another one. When a worker climbs the ladder, the increasing of the weight is such that the preset threshold force value is reached and therefore the wheel pushes against the pushing means and, by compressing them, it moves toward the retracted position, allowing the braking body to contact gradually the ground (in fact the ladder is lowered in the amount of retraction of the wheel, leading to the braking body contact). In this configuration the wheel can no longer carry out its purpose, as its whole weight is mainly acting on the braking body with the unloaded wheel and the ladder remains firmly fixed in the position .

This solution is particularly advantageous not only because it is constructively easy but also because it does not need any prior activation by the user. Automatically, depending on the presence of the worker on the ladder (and so depending on the weight acting on the ladder) , such braking system activates or deactivates, making the ladder safe and the overall system extremely flexible and functional. The accidental occurrence where the user climbs the ladder and forgets to insert the blocking system cannot occur anymore.

It is also here described a ladder comprising a first couple of bars (2) hinged to a second couple of bars (3) and with said two pairs of bars mutually rotatable between a position of use wherein are spread out and a stand position wherein they are close to each other. It is therefore comprised a bar 43, hinged through one of its end to the frame and fixed through the opposite end to a loading bed (6')· Said bar 43 is rotatable between a position of use wherein it conducts said loading bed in stand at least on the end of one of the two couples of bars (2, 3) resulting in a horizontal position and a rest position wherein it rotates in proximity of the frame.

Further advantages are inferable from the depending claims .

Brief description of drawings

Further features and advantages of the present ladder, according to the invention, will result to be clearer with the description that follows of some embodiments, made to illustrate but not to limit, with reference to the attached drawings, wherein:

- Figure 1 shows a side view of the ladder according to the present invention;

- Figure 2 represents in a section the braking device applied to such ladder in the configuration wherein is allowed the movement of the wheel that emerges from the hollow body and with the hollow body raised with respect to the ground; - Figure 3 represents in a section the braking device applied to such ladder in the configuration wherein the wheel is internally retracted inside the hollow body and with the hollow body resting to the ground;

- Figure 4 and figure 5 show the ladder in the configuration with the extended wheels and therefore translatable and with the retracted wheels and therefore fixed to the ground;

- Te sequence of figures 6A and 6B represents a further variation of the invention;

- Figures from 7 to 9 show a utmost loading bed of the ladder, particularly functional, whose aim is to carry out a storage function.

Description of some preferred embodiments

Referring to figures from 1 to 5, a possible preferred first embodiment of such ladder of the transportable type is described and comprising:

A frame (2, 3, 4) suitable for allowing the arrangement of one or more supporting surfaces (6, 6') through which a user can reach one or more different heights from the ground;

At least a wheel (19) forming a support point to the ground, said wheel being suitable for allowing the movement of the ladder;

- A braking device (5, 10, 15, 20) to block the wheel.

The braking device comprises a hollow body (5) into which a septum (15) is arranged and to which said wheel is fixed, said septum (15) being arranged into said hollow body in a translatable manner in such a manner that it can move between said extended position, wherein the wheel results emerging from said hollow body and said retracted position, wherein the wheel results retracted inside said hollow body. Pushing means (10) are further comprised and configured in such a manner to maintain said septum in said lowered position for force values (R) that act on said septum, in the direction of movement towards the raised position, that are below a predetermined threshold value and allow a movement of the septum towards the raised position, when reached or exceeded this threshold force value.

More in detail, referring to figure 1, such ladder 1 is described.

Such ladder includes a frame (2, 3) formed by a first couple of bars that are generally parallel and distanced between them. They are generally in-built together through (one or more) diagonal bars, connecting them. Such couple of bars is then hinged to a further couple of bars 3, being also generally parallel, distanced and in-built each other.

Figure 1 shows with number 50 the hinging point between said two couples of bars, in such a manner that said two couples of bars (only the front ones are visible, as it is a lateral view) have a rotating motion around that point, opening and closing as a compass or as scissors .

Figure 1 represents the open configuration wherein the two couples of bars are distanced one to the other, thus defining four contact points to the ground, arranged in such a manner that such operating position results stable, as background art.

The opposing movement leads the two couples to an approaching position one to the other, thus closing the ladder at the end of use, for example in order to place it with little encumbrance, as background art.

According to the invention, the ladder is equipped with wheels 19, preferably one for each support point (preferably four wheels, that is one for each support point) , in such a way to be easily moved from a point to another one during its use, that is in its open configuration in use.

There are preferably four wheels, that is each bar (3, 4 ) is equipped with a wheel, for example of the adjustable or of the oscillating type, which are very well known in the technical field.

The wheel is though arranged in combination with an innovative braking system, by which, when the ladder is subjected to his weight only (or in any case it is subjected to a weight which is below a selected threshold value) , the wheels result working normally. When instead an excess load, which exceeds a preset threshold value, occurs on the ladder, in this way such system prevents automatically the normal operation of the wheels, anchoring the ladder to the ground, making it stable and safe .

In this way, when a user climbs the ladder, it results blocked to the ground and when he climbs down, the ladder can easily be moved thanks to the provided wheels.

Explaining more in detail this invention, at the ends of the bars (2, 3) (such ends forming the support points) a hollow body, preferably a cylindrical element 5' , is fixed through each end.

Inside such cylindrical element 5' , is arranged a first fixed septum 20 which can be fixed to the cylindrical element, for example using common screws or riveting 17, as shown in figures 2 and 3, or different connection systems such as high resistance adhesive.

At the same time such riveting can be used to block the end of the bar (2, 3) to such cylindrical element 5 ' .

Then is included an underlying septum 15, which is translatable through the cylindrical element wherein it is inserted in such a way to move closer or away in respect to the fixed septum. An end position is obviously provided. It blocks the maximum range of such mobile septum and it is represented below in figure 2 with the inserts 16 (for example screws or rivets) that form an end position shoulder.

Otherwise, a different production of the cylinder may be considered to form shoulders but in this case a possible access or opening on top would be necessary in order to assemble the different parts.

On the upper part the maximum stroke is obviously limited by the fixed septum 20.

Definitely, the mobile septum 15 shifts through the distance between the lower setscrew 16 and the upper septum.

As shown in figure 2 as well, the wheel is then connected to the lower septum 15, fixing the support 18 of the wheel to the septum, for example using common bolts and nuts.

Finally, a calibrated spring 10 is arranged in the space between the two septum, in such a manner that it maintains the mobile septum 15 in contact with the lower setscrew 16 for predetermined threshold force value.

The arrangement of the lower setscrew 16 and the sizes of the wheel with its support result in such a manner that in said position, (position on figure 2) the wheel emerges at least in part from the cylindrical element, thus resulting in contact with the ground and so with the cylindrical element which results raised from the ground .

In this way the wheel carries out its normal purpose and the ladder can be easily dragged from a point to another one.

The inner space of the cylindrical element results in such a manner that the wheel rotates freely if it is of the oscillating type. Therefore, the spring 10 is calibrated in such a manner that, if a force F acts by compressing it, being the force F below a preset threshold force value, then the wheel maintains said extended configuration.

In particular, the wheel undergoes a reaction R from the ground to the upper part and such reaction results obviously in the equivalent modulus to the weight load P including the ladder and possible other weights on it. The spring is therefore subjected to a compression load which is equivalent to the total weight acting on the ladder (obviously the weight of the ladder is considered) .

Such reaction, as shown in figure 2, is therefore opposed with the pushing force (Sp) of the spring. If the spring is calibrated correctly, the wheel can remain in the extended position (without the movement of the septum 15 towards the septum 20) when the ground reaction is below a threshold value. Such threshold value can be fixed to the weight value of the unloaded ladder or can be slightly superior to that value.

When instead a subject uses the ladder, the value in the form of reaction R increases considerably and therefore, if the predetermined threshold value has exceeded, the spring will begin to be compressed in such a manner that the septum 15 can move towards the septum 20. With a proper calibration of the spring, such movement continues until the wheel has returned into the hollow (as per figure 3) and with said hollow element that reaches the ground firmly. In this configuration, the wheel results de facto unloaded and so it is prevented from carrying out its purpose and the whole ladder rests firmly to the cylindrical element with its whole weight.

As per figure 4, the ladder configuration is shown without any person on it and so the emerging wheels allow the movement of the ladder in any direction. Figure 5 simulates the presence of a subject on the ladder. The ladder is affected by the additional weight which causes the compression of the spring and so the retraction of the wheels, thus acquiring the configuration where the wheels are completely retracted inside the cylindrical element.

Obviously the solution with the spring is the best one, as it is the simplest and the most functional constructively .

Moreover, thanks to that solution, no specific operation is required by the user, that means he does not need to activate any braking device, as such braking device is automatically activated depending on the weight acting on the ladder.

However, as an alternative, the spring may be replaced by hydraulic or pneumatic systems that are functional but for sure more complex and expensive and they complicate the structure of the solution.

For example, it may be possible to create a pneumatic circuit which injects air or gas between two septum according to a certain pressure depending on the measured weight (the weight is detected by a weight detector) in such a manner that the wheel emerges outwards. When the detector detects a weight increase over a preset threshold, so a progressive gas unloading can be considered, in such a manner that the septum can begin to shift towards the fixed septum.

As the description explains, such solution is possible but certainly more difficult.

The basis of the cylindrical body can be favourably covered by a high friction material, for example rubber.

A further variation of the invention is described in figures 6A and 6B.

In this variation the braking body can be constituted by the same end of the bar (2, 3) of the frame (generally covered by rubber material) . It is enough to couple the wheel which is linked to a spring 100 through a horizontal surface integrated to that end. The spring, in rest condition, maintains the wheels in extended position in respect to said end, as per figure 6A. As long as the ladder is unloaded, the wheels maintains such position. When a user climb the ladder, or a weight which exceeds the predetermined threshold value acts, so the spring compresses itself and the end of the bar contacts the ground, acting as braking body (see figure 6B) .

Going further with the structural description of the invention, the opening/closing system of the ladder comprises a leverage 4 which is described below.

As shown in figure 1, each step 6 has a couple of bars 40, separated one from the other, below the steps and connected to it (only the front one bar is shown as it is a lateral view) . Each bar is hinged to an oblique bar 42 linked to another bar 41 hinged through an end to said bar 42 and through the opposite end to the bar 2 to the frame. The bars 40 placed under the steps 6 are hinged through an end to the bar 3 of the frame.

In this way, when the two bars of the frame 2 and 3 are moved closer each other, the steps 6 rotate clockwise, raising vertically and when the two bars 2 and 3 are open, the steps rotate counterclockwise in horizontal position.

As further shown in figure 1 as well, the ladder is equipped with an upper loading bed 6' , which is created in such a way to result particularly stable, by allowing at the same time the support of more than 20 kilos weights.

Such loading bed is preferably of size between 58cm x 30 cm, even if, obviously, such sizes are not binding but only show the wide available area.

Such storage loading bed can be closed in a closing position wherein it is at the same level of the bar 3 or it is positioned in a position of use as per figure 1.

Describing more in details figure 7, there is a further bar 43 which is hinged to the same mutual hinging point between the bar 2 and 3.

Such bar is preferably comprised in the space between the bar 2 and 3 and hinged to the same hinging point of the bar 2 and 3.

The opposite part of the bar 43 is fixed to the loading bed 6' . Obviously, in this case too, the two parallel and distanced bars 43 are provided.

Such bar can be rotated from the working position, where the loading bed 6' rests on the end of the two bars 3 as per figure 7, that is it rotates towards the bar 3 and vice versa.

In this way, when the bar 3 is closed towards the bar 2, it is also possible to rotate the bar 43 near the bar 3, having a compact closed ladder, with all elements close each other.

Figure 7 shows further a safety block 51, in the form of an in-built protrusion to the bar 2 and where the bar 43 rests when it moves to the working position as per figure 8. In this way, the weight of the loading bed itself would rotate the bar 43 counterclockwise and so against such stop 51, guaranteeing a stable position. As per figure 9, a further safety can be constituted by a sliding and extractable stop 100, in such a manner that it can be inserted inside the receiving hole of the bar 3, blocking such position.

This solution of storage loading bed can be used on any ladder and not necessarily on the above mentioned ladder with such braking device.

In such description, with the term ladder is meant any type of device with superimposed loading beds which can be fixed or mobile (for example vertically translatable or in horizontal position when the ladder is open in configuration of use) to allow a user to reach more different heights, for example stairs, domestic or professional stairs that can be opened/closed as scissors or telescopic elevation stepladders, ladder of the platform type, platforms-ladder or even simple platforms- ladder with lifting loading bed movable to different heights or with more fixed superimposed loading beds, etc.

Claims

A ladder (1) of the transportable type comprising:

A frame (2, 3, 4) suitable for allowing the arrangement of one or more supporting surfaces (6) through which a user can reach one or more different heights from the ground;

A braking device (5, 10, 15, 20);

Characterized in that said braking device comprising a braking body (5') cooperating with said wheel, said wheel being arranged in such a manner to result movable between an extended position, wherein it emerges respect to the braking body, contacting in use the ground, and a retracted position wherein, in use, the braking body contacts the ground exerting a braking action and wherein, further, pushing means (10) are comprised and configured in such a manner to maintain said wheel in said extended position for force values that act on it, in the direction of movement towards the retracted position, that are below a predetermined threshold value and allow a movement of the wheel towards the retracted position, when reached or exceeded this threshold force value, in such a manner that when the wheel is retracting, the braking body moves to contact the ground.

A ladder (1), as per claim 1, wherein said braking device comprises a hollow body (5) into which a septum (15) is arranged and to which said wheel is fixed, said septum (15) being arranged into said hollow body in a translatable manner in such a manner that it can move between said extended position, wherein the wheel results emerging from said hollow body and said retracted position, wherein the wheel results retracted inside said hollow body.

3. A ladder (1), as per claim 1 or 2, wherein the wheel is arranged in correspondence or in proximity of the support point (5) of the frame to the ground.

4 . A ladder (1), as per claim 1, wherein said pushing means are in the form of elastic means (15, 20) .

A ladder (1), as per claim 4, wherein said elastic means are in the form of at least one spring.

6. A ladder (1), as per one or more previous claims, wherein said elastic means are arranged between said two septum (15, 20).

7. A ladder (1), as per claim 1, wherein said pushing means are of hydraulic or pneumatic type.

8. A ladder (1), as per one or more previous claims, wherein said hollow body (5) is in the form of a blind duct (5' ) wherein a chamber is comprised which is delimited on the upper part by a wall (20) which makes blind said hollow body and on the lower part by the translatable septum (15).

9. A ladder (1), as per claim 8, wherein said duct is of generally cylindrical shape.

10. A ladder (1), as per claim 8 or 9, wherein said duct is connected to the extremity of the support point.

11. A ladder (1), as per one or more previous claims, wherein said frame comprises a first couple of bars (2) hinged to a second couple of bars (3) and with said two pairs of bars mutually rotatable between a position of use wherein are spread out and a stand position wherein they are close to each other.

12. A ladder, as per one or more previous claims, wherein a bar (43), hinged through one of its end to the frame and fixed through the opposite end to a loading bed (6'), is comprised, said bar (43) being rotatable between a position of use wherein it conducts said loading bed in stand at least on the end of one of the two couples of bars (2, 3) resulting in a horizontal position and a rest position wherein it rotates in proximity of the frame .

13. A ladder, as per claim 12, wherein the couple of bars (3) has a superior length in comparison with the couple of bars (2) , in such a way that in said position of use the loading bed is in horizontal position in stand on the end of the bars