EP2627849B1

EP2627849B1 - Support apparatus and foldable ladder, stepladder or scaffolding with such a support apparatus

Info

Publication number: EP2627849B1
Application number: EP10771223.4A
Authority: EP
Inventors: Karolus Theodorus Wilhelmina Maria Bus; Arnaldo Roberto Vonk
Original assignee: SMART LEVEL CO BV
Current assignee: SMART LEVEL CO BV
Priority date: 2010-10-13
Filing date: 2010-10-13
Publication date: 2015-03-11
Anticipated expiration: 2030-10-13
Also published as: ES2538821T3; EP2627849A1; WO2012050433A1

Description

The invention relates to a support apparatus, comprising legs which at one end thereof are connected to each other by means of a hinge arrangement and which at the other end thereof comprise respective support feet, said legs each comprising leg sections which are adjustable with respect to each other for providing an adjustable leg length, a control arrangement being provided comprising a locking mechanism for locking respectively unlocking the leg sections of each leg as well as an operating mechanism allowing simultaneous operation of the locking mechanisms of respective legs. Such a support apparatus is for example known from US 3 016 103 .
Support structures comprising a frame having adjustable legs comprising a control arrangement with a locking mechanism and an operating mechanism as mentioned above have been described in yet unpublished patent applications by the inventor. Simultaneously unlocking the leg sections of each leg enables easy and careful stable positioning of a support structure such as a ladder or stepladder on uneven surfaces by individual adjustment of the leg sections with respect to each other. Furthermore, the adjustable leg sections may be used for level positioning of for example a bucket tray on the ladder or stepladder.
In an embodiment of a support structure according to the yet unpublished patent applications a ladder comprises adjustable legs that are hingedly connected with respect to each other and the operating mechanisms of which are interconnected by two rods that are rotatably connected to the frame of the ladder. The rods are interconnected by two elements that are hingedly connected with respect to each other. By displacing a manual-operating element one of the rods is rotated. When the ladder is in operational mode, rotation of the one rod causes an axial displacement of the hingedly connected beam elements resulting in a rotation of the other rod. This causes simultaneous unlocking of the locking mechanisms of all adjustable legs by the operating mechanisms. As a result, the leg sections of all legs can individually be adjusted with respect to each other to enable stable positioning of the ladder on a surface.
The interconnection in the ladders described in the yet unpublished patent applications for achieving simultaneous unlocking and locking of the adjustable legs involves many moving parts. Moreover, some of the moving parts are accessible from the outside. This could make them vulnerable for getting polluted and/or damaged as they are exposed to environmental influences such as dirt.
It is an object of the present invention to provide a support apparatus for application in a ladder or stepladder, which has an improved reliability.
This object is achieved by a support apparatus according to the present invention wherein elements of the operating mechanism are at least partly integrated in, or are at least partly located at, the hinge arrangement. In this way the hinge arrangement can have a double function. Besides its function to hingedly connect the adjustable legs of the support apparatus with respect to each other, the hinge arrangement, such as a commonly known rotary hinge, can also displace other elements of the operating mechanisms, which are not integrated in the hinge arrangement, for unlocking and locking the locking mechanisms of the connected adjustable legs. As a result, such hinge arrangement can enable a reduction of the number of moving parts of the operating mechanism. In addition, the elements of the operating mechanism that are integrated in the hinge arrangement are less vulnerable for getting polluted and/or damaged.
In an embodiment of the present invention the operating mechanism comprises at least one swivel member which is rotatable with respect to a hinge axis, as well as a transmission element which cooperates with said swivel member and with the locking mechanism of one of the legs providing control of said locking mechanism upon rotation of the swivel member. The double function of the hinge arrangement can be obtained by integrating the swivel member, e.g. a disc-shaped element that is rotatable around a hinge axis. Rotation of the swivel member results in an axial displacement of a cooperating transmission element, such as a rod or a bar, which is hingedly connected to the swivel member for example rotatable around a pivot point of the swivel member. Axial displacement of the cooperating transmission element leads to unlocking and locking of the locking mechanism of one of the hingedly connected legs of the support apparatus.
In an embodiment of the present invention a control element is provided for controlling the at least one swivel member, as well as with a manual operator, said control element providing rotation of the swivel member upon operation of the manual operator, said control element and manual operator being located at the other of the legs. The control element, which for example also is a rod or a bar, can axially be displaced in the direction of the at least one swivel member by manually operating the manual operator such as a lever. Such axial displacement of the control element can cause a rotation of the at least one swivel member around the hinge axis and consequently an axial displacement of the abovementioned transmission element, which results in unlocking of the locking mechanism of the one leg of the support apparatus. In this way an axial displacement of the control element that is located at the other leg leads to an axial displacement of the transmission element that is located at the hingedly connected one leg.
In an embodiment of the present invention a further transmission element is provided at said other leg, said further transmission element being operable by the manual operator and providing control of the locking mechanism of the other leg. By operating the manual operator the further transmission element, such as a rod or a bar, can be axially displaced. This axial displacement of the further transmission element can unlock and lock the locking mechanism of the other leg of the support apparatus.
As described above, the manual operator also cooperates with the control element. By operating the manual operator the control element and the further transmission element can be axially displaced simultaneously. However, for achieving simultaneous control of the locking mechanisms in the one and other legs of the support apparatus, the operating mechanism has to be arranged such that the control element and the further transmission element are axially displaced in opposite directions.
In an embodiment of the present invention the transmission element of said one leg is hingedly connected to the at least one swivel member. In this way the rotation of the at least one swivel member can be translated into an axial displacement of the transmission element, such as a rod or a bar in the one leg of the support apparatus. As described above the transmission element can for example be rotatable around a pivot point of the at least one swivel member.
In an embodiment of the present invention a swivel member has a control abutment that is located opposite the control element of said other leg in a first rotated position or in a first set of rotated positions of the legs with respect to each other and which is remote or removed from said control abutment in other rotated positions of the legs, so as to bring the control element in abutting relationship with the control abutment of said swivel member while the latter is in the first rotated position or in the first set of rotated positions. The control abutment can for example be a recess in a circumferential rim of the swivel member. Axial displacement of the control element in the direction of the swivel member can bring the control element in abutting relationship with the control abutment if the latter is positioned opposite the control element of the other leg. This can be done by rotating the one and other legs of the support apparatus with respect to each other such that a first rotated position is obtained. When in a first rotated position the control element can be brought in abutting relationship with the control abutment by an axial displacement of the former. As a result of the abutting relationship between the control element and the control abutment the swivel member is rotated around the hinge axis.
Depending on the arrangement of a single control abutment or on the implementation of multiple control abutments in the circumferential rim of the swivel member, the one and other legs can be rotated with respect to each other such that a position out of a first set of rotated positions is obtained in which the control abutment is positioned opposite the control element. In each of such positions simultaneous control of the locking mechanisms in the one and other legs of the support apparatus can be achieved.
In other rotated positions the control abutment is not positioned opposite and proximate the control element. As a result the control element cannot engage with the control abutment of the swivel member and the swivel member cannot be rotated around the hinge axis. In such cases, operating the manual operator only leads to controlling the locking mechanism of the other leg of the support apparatus.
In an embodiment of the present invention the legs are directly connected to each other through a hinge arrangement, the transmission element of said one leg and the control abutment for cooperation with the control element of the other leg being associated with one and the same swivel member. Such support apparatus can be applied in for example a ladder or stepladder.
In an embodiment of the present invention an intermediate section is provided and the legs are connected to opposite ends of said intermediate section through respective hinge arrangements, said hinge arrangements each being provided with a swivel member, said swivel members being interconnected through a coupling element allowing simultaneous and coupled rotation of said swivel members, the transmission element of said one leg being connected to the respective swivel member and the control abutment being arranged on the other swivel member. Such support apparatus can for example be applied in scaffolding and/or a platform ladder. In operation, the intermediate section is positioned substantially horizontally to enable level support e.g. of a person and/or of equipment. Simultaneously controlling the locking mechanisms in the one and other legs of the support apparatus can be achieved by operating the manual operator that is located at the other leg. As described above, operating the manual operator results in an axial displacement in opposite directions of the control and transmission elements in the other leg. The control element which is axially displaced in the direction of the abovementioned other swivel member can be brought into abutting relationship with the control abutment of the other swivel member when the one and other legs are positioned with respect to each other such that a first rotated position or a position out of a first set of rotated positions is obtained. As a result of the abutting relationship between the control element of the other leg and the control abutment the other swivel member, the other swivel member is rotated around the hinge axis. As the other and one swivel members are interconnected by a coupling element, such as a rod or a bar, of the intermediate section, a simultaneous and coupled rotation of these swivel members is achieved. As a result of the rotation of the one swivel member the cooperating transmission element of the one leg of the support apparatus is axially displaced such that the locking mechanism of the one leg can be controlled. It is clear that operating the manual operator located at the other leg results in a simultaneous unlocking and locking of the locking mechanisms of the one and other legs of the support apparatus comprising an intermediate section.
In an embodiment of the present invention blocking elements are provided which are displaceable between an active position in which the legs are blocked against rotation with respect to each other at a sharp angle, and an inactive position allowing rotation of the legs with respect to each other. The blocking elements enable fixation of the hinge arrangement such that in the active position the one and other legs of the support apparatus cannot be rotated with respect to each other. In this way a first rotated position or a position out of a first set of rotated positions in which the one and other legs are positioned at a sharp angle with respect to each other can be maintained. In this first rotated position the abovementioned simultaneous unlocking and locking of the locking mechanism can be achieved as the control abutment of the swivel member is positioned opposite the control element of the other leg. When the blocking elements are in the inactive position, the one and other legs of the support apparatus can be rotated freely with respect to each other. This for example allows for adjusting the angle between the one and other legs in any desired manner.
In an embodiment of the present invention the first rotated position or the first set of rotated positions is defined by said sharp angle. A sharp angle between the one and other legs allows the support apparatus to be used for example in a ladder and/or in scaffolding and/or in a platform ladder. Depending on the implementation of the control abutment of the swivel member, the locking mechanisms of the one and other legs can be unlocked and locked simultaneously when the control abutment is in a first rotated position or in a position out of a first set of rotated positions, which are defined by a sharp angle between the one and other legs.
In an embodiment of the present invention the blocking elements have a second active position in which the legs are aligned with respect to each other. In the second active position the hinge arrangement is blocked when the angle between the one and other legs of the support apparatus is 180°. In this case, the support apparatus can for example be used in a so-called lean-to ladder and/or in a stepladder. As mentioned above, the first rotated position or the first set of rotated positions is defined by a sharp angle. This means that when the blocking elements are in the second active position the control abutment of the swivel member is not positioned opposite the control element of the other leg. As a result, the locking mechanism of the one leg cannot be unlocked or locked by operating the manual operator. In this case, operating the manual operator only results in unlocking or locking the locking mechanism of the other leg.
In an embodiment of the present invention the hinge arrangement comprises essentially flat and parallel hinge plates which are rotatable with respect to each other around a hinge axis perpendicular with respect to said plates which are each connected to a respective leg, the swivel member being rotatable around said hinge axis as well.
In an embodiment of the present invention at least one of the hinge plates has a circumferential rim within which the swivel member is contained. In this way the swivel member is at least partly integrated such that it is at least not entirely accessible from the outside and is less vulnerable for getting polluted and/or damaged.
In an embodiment of the present invention the operating mechanism comprises a pulling member that extends between a locking mechanism located on the one leg and a manual operator located on the other leg and/or between a locking mechanism and a manual operator both located on the other leg. In the case that pulling members are provided between the locking mechanisms located on both the one and other legs and the manual operator located on the other leg, it is possible to simultaneously unlock and lock the locking mechanisms on both the one and other legs by moving the pulling member using the manual operator that is located on the other leg when the one and other legs are in a first rotated position or in a first set of rotated positions with respect to each other. In this case the support apparatus can be configured without rods to implement a transmission element between the swivel member and the locking mechanism on the one leg, a control element between the manual operator and the swivel member and a further transmission element between the manual operator and the locking mechanism on the other leg. An advantage of this embodiment of the support apparatus according to the present invention is that the support apparatus can be configured without many movable rods for simultaneously operating the locking mechanisms on the one and other legs. This leads to a simplified configuration of at least the operating mechanism and a reduction of possible failure of its operation. As a result, reliable operation of the support apparatus as a whole is improved.
In the case that a pulling member is provided only between the locking mechanism on the one leg and the manual operator on the other leg, a further transmission element still has to be applied between said manual operator and the locking mechanism on the other leg in order to enable simultaneous operation of the locking mechanisms on the one and other legs when these legs are in a first rotated position or in a first set of rotated positions with respect to each other.
In the case that a pulling member is provided only between the locking mechanism on the other leg and said manual operator, a control element between the manual operator and the control abutment of the swivel member and a transmission element between the swivel member and the locking mechanism on the one leg still have to be applied to enable simultaneous operation of the locking mechanisms on the one and other legs when these legs are in a first rotated position or in a first set of rotated positions with respect to each other.
In an embodiment of the present invention the pulling member is movable around a hinge axis of the hinge arrangement. The pulling member can thereby be supported and/or guided by a swivel member. It is also possible that the pulling member is supported and/or guided by the axis of the hinge arrangement.
In an embodiment of the present invention the pulling member is a cable or a chain or a belt. It will be clear to the person skilled in the art that more alternatives can be envisaged for implementation of the pulling member.
In an embodiment of the present invention a tensioning device is provided that is arranged for tensioning the pulling members such that operating the manual operator allows simultaneous operation of the locking mechanisms of the respective legs when these legs are in a first rotated position or in a first set of rotated positions with respect to each other. When the one and other legs are not in the aforementioned first rotated position or first set of rotated positions the tensioning device is not able to adjust the length of the pulling members such that simultaneous locking and unlocking can occur. As a result, the locking mechanisms located on the one legs remain locked while the locking mechanisms located on the other legs can be unlocked and locked by operating the manual operator.
According to another aspect of the present invention a foldable ladder or stepladder or scaffolding is provided comprising a first as well as a second support apparatus which are arranged parallel to each other and which are interconnected by means of parallel and evenly spaced beams, wherein the control arrangements of both support apparatuses are interconnected allowing simultaneous control of all four legs. The control arrangements of the first and second support apparatuses can be interconnected by a rod or a bar. The rod cooperates with the manual operator of at least one of the support apparatuses. By operating the manual operator of at least one of the support apparatuses the rod rotates and causes a simultaneous activation of the control arrangements of both support apparatuses. As a result, depending on the position of these legs, as has been described above, the length of all four legs can be adjusted simultaneously.
The rod that interconnects the control arrangements can for example be arranged below and/or behind one of the parallel beams that interconnect the first and second support apparatuses. However, the rod could also be integrated in one of these parallel beams. In that case the rod would not be accessible from the outside and less vulnerable for getting obstructed and/or damaged.
In an embodiment of the foldable ladder or stepladder or scaffolding according to the present invention activating elements are provided which are operable to manually activate the control arrangement of at least one of the support apparatuses. The activating elements can be levers that upon manual operation as described above allow simultaneous unlocking and locking of the locking mechanisms.
The invention will be explained in more detail below with reference to drawings in which illustrative embodiments of the invention are shown. The person skilled in the art will realize that other alternatives and equivalent embodiments of the invention can be conceived and reduced to practice without departing from the scope of the present invention.

Figure 1 shows a partly exploded view in perspective of a ladder comprising a first and a second support apparatus according to the present invention.
Figure 2 shows a perspective view of a lean-to ladder or stepladder comprising a first and a second support apparatus according to the present invention.
Figure 3 shows a perspective view of a scaffolding or platform ladder comprising a first and a second support apparatus according to the present invention.
Figure 4 shows a side elevation of a hinge arrangement according to the present invention, wherein a control abutment of a swivel member is positioned opposite a control element of the other leg when the legs of the support apparatus are in a first rotated position.
Figure 5 shows a side elevation of the hinge arrangement, wherein the control element is in abutting relationship with the control abutment of the swivel member.
Figure 6 shows a side elevation of the hinge arrangement, wherein the one leg and the other leg are aligned with respect to each other.
Figure 7 shows a front view of the hinge arrangement.
Figure 8a shows a perspective view of two interconnected control arrangements according to the present invention in the case that two support apparatuses have been applied in for example a ladder.
Figure 8b shows a perspective view of two interconnected control arrangements according to the present invention in the case that two support apparatuses comprising intermediate sections have been applied in a scaffolding or platform ladder.
Figure 9a shows a detailed side elevation of an embodiment of the control arrangement of the other leg of the support apparatus according to the present invention wherein the locking mechanism is in the locked position.
Figure 9b shows a perspective view of a catch element of the locking mechanism.
Figure 9c shows a detailed side elevation of the embodiment of the control arrangement of the other leg of the support apparatus according to the present invention wherein the locking mechanism is in the unlocked position.
Figure 10a shows a perspective view of two interconnected support apparatuses according to the present invention wherein the two operating mechanisms comprise pulling members for locking and unlocking the locking mechanisms located on the one legs of the support apparatuses.
Figure 10b shows a perspective view of two interconnected support apparatuses comprising intermediate sections that have been applied in a scaffolding or platform ladder, wherein the two operating mechanisms comprise pulling members for locking and unlocking the locking mechanisms located on the one legs of the support apparatuses.
Figure 11 shows a side elevation of a hinge arrangement according to the present invention, showing a pulling member that is arranged around a swivel member of a hinge arrangement when the legs of the support apparatus are in a first rotated position with respect to each other.

The figures are not necessarily drawn to scale. In the figures identical components are denoted by the same reference numerals.
Figure 1 shows a partly exploded view in perspective of a ladder 2 comprising a first support apparatus 1a and a second support apparatus 1b according to the present invention. The first and second support apparatuses 1a, 1b are arranged parallel to each other and are interconnected by means of parallel and evenly spaced beams 3. Each support apparatus 1a, 1b of the ladder 2 comprises two legs 4, 5 which in the remainder of this text will be indicated as the one leg 4 and the other leg 5, respectively. At one end, the one leg 4 and other leg 5 are connected to each other at a sharp angle (α) by means of a hinge arrangement 6. At the other end, the one leg 4 and other leg 5 comprise respective support feet 7. The legs 4, 5 each comprise leg sections 8, 9 which are axially adjustable with respect to each other for providing an adjustable leg length. The length, over which movement is possible, may for instance be 20 cm. Other lengths are possible.
Each support apparatus 1a, 1b is provided with a control arrangement which comprises a locking mechanism 11 for locking respectively unlocking the leg sections 8 of each leg 4, 5 as well as an operating mechanism allowing simultaneous operation of the locking mechanisms 11 of the one 4 and other 5 legs.
The operating mechanism comprises a swivel member 13which is integrated in the hinge arrangement 6 and is rotatable with respect to a hinge axis 14. The operating mechanism also comprises a transmission element 15 such as a rod or a bar which cooperates with swivel member 13 and with locking mechanism 11 of the one leg 4. By integrating a swivel member 13, e.g. a disc-shaped element, the hinge arrangement 6 has a double function. Besides its function to hingedly connect the adjustable legs 4, 5 with respect to each other, it can displace the transmission element 15 resulting in unlocking and locking of the locking mechanism 11 of the one leg 4.
At the other leg 5 a manual operator 16, e.g. a lever, and a control element 17, e.g. a rod or a bar, are provided. With the manual operator 16 in its initial position all locking mechanisms 11 are locked and the leg sections 8 can at least not axially be moved. By operating the manual operator 16 the control element 17 is axially displaced in the direction of the swivel member 13. As a result of this axial displacement swivel member 13 is rotated around hinge axis 14 and transmission element 15 is axially displaced in the direction of locking mechanism 11 of the one leg 4. In this way locking mechanism 11 of the one leg 4 can be unlocked by operating the manual operator 16.
To unlock the locking mechanism 11 of the other leg 5, a further transmission element 18, e.g. a rod or a bar, is provided which is axially displaceable at the same time as control element 17 by operating the manual operator 16. However, for achieving simultaneous control of the locking mechanisms 11 in the one leg 4 and the other leg 5 of support apparatus 1, the operating mechanism has to be arranged such that control element 17 and further transmission element 18 are axially displaced in opposite directions. This can be achieved by using a pushing block 19 that cooperates with the manual operator 16 and is located between control element 17 and further transmission element 18.
By interconnecting the control arrangements of the first and second support apparatuses 1a, 1b simultaneous adjustment of the length of all four legs 4, 5 of the ladder 2 can be achieved. This interconnection can be achieved by a rod or a bar 20 that cooperates with the manual operator 16 of support apparatus 1a. By operating manual operator 16 the rod 20 rotates and causes a simultaneous activation of the control arrangements of both support apparatuses 1a, 1b. As a result, depending on the position of the legs as has been described above, the length of all four legs can be adjusted simultaneously.
The rod 20 that interconnects the two control arrangements can for example be arranged below and/or behind one of the parallel beams 3 that interconnect the first and second support apparatuses 1a, 1b. However, the rod 20 can also be integrated in one of these parallel beams 3 as is shown in figure 1. In this case the rod 20 is not accessible from the outside and is therefore less vulnerable for getting obstructed and/or damaged.
Figure 2 shows a perspective view of a lean-to ladder or a stepladder 21 comprising a first support apparatus 1a and a second support apparatus 1b according to the present invention. In a lean-to ladder 21 the one leg 4 and the other leg 5 are aligned with respect to each other. As will be explained below, the swivel member 13 is arranged such that the when the angle (α) between the one and other legs 4, 5 is substantially 180°, operating the manual operator 16 only allows controlling the locking mechanisms 11 of the other legs 5 of the first and the second support apparatuses 1a, 1b.
Figure 3 shows a perspective view of a scaffolding or platform ladder 22 comprising a first and a second support apparatus 1a, 1b according to the present invention. In this case the support apparatuses 1a, 1b each comprise an intermediate section 23. The one and other legs 4, 5 are connected to opposite ends of said intermediate section 23 through respective hinge arrangements 6. Each of these hinge arrangements 6 comprises a swivel member 13. The swivel members 13 are interconnected through a coupling element 24 that is integrated in the intermediate section 23. The coupling element 24 allows simultaneous and coupled rotation of the swivel members 13. The transmission element 15 of the one leg 4 of the support apparatus 1a is connected to the one swivel member 13. The control element 17 of the other leg 5 can be brought into contact with the other swivel member 13 for making it rotate. This will be explained in more detail below.
Figure 4 shows a side elevation of a hinge arrangement 6 according to the present invention wherein a swivel member 13 has been integrated in the hinge arrangement 6. The hinge arrangement is rotatably connected to a hinge axis 14 and has a control abutment 25, which for example is a recess in a circumferential rim of the swivel member 13. The control abutment 25 is located opposite the control element 17 of the other leg 5 in a first rotated position or in a position out of a first set of rotated positions that can be obtained by rotating the one and other legs 4, 5 with respect to each other.
In different embodiments, the control abutment can be implemented as a single abutment or as multiple abutments 25 that are arranged at different positions along the circumferential rim of the swivel member 13. Depending on the implementation of the control abutment 25, the locking mechanisms 11 of the one and other legs 4,5 can be unlocked and locked simultaneously when the control abutment 25 is in a first rotated position or in a position out of a first set of rotated positions, which are defined by a sharp angle (α) between the one and other legs 4, 5.
In other rotated positions the control abutment 25 is not positioned opposite the control element 17. As a result the control element 17 cannot engage with the control abutment 25 of the swivel member 13 and the swivel member cannot be rotated around the hinge axis 14. In such cases, operating the manual operator 16 only leads to controlling the locking mechanism 11 of the other leg 5 of the support apparatus 1a; 1b.
The hinge arrangement 6 furthermore comprises a blocking element 26 which is displaceable between an active position and inactive position by a lever 27. In the active position the one and other legs 4, 5 are blocked against rotation with respect to each other at a sharp angle (α). In the inactive position the one and other legs 4,5 are allowed to rotate freely with respect to each other. This for example allows adjustment of the angle (α) between the one and other legs 4, 5.
Figure 4 shows the active position in which the blocking element 26 fastens the hinge arrangement 6 such that the one and other legs 4, 5 of the support apparatus 1a; 1b cannot be rotated with respect to each other. In this way, a first rotated position or a position out of a first set of rotated positions in which the one and other legs 4, 5 are positioned at a sharp angle (α) with respect to each other can be maintained.
In this first rotated position, the abovementioned simultaneous unlocking and locking of the locking mechanism 11 can be achieved as the control abutment 25 of the swivel member 13 is positioned opposite the control element 17 of the other leg 5.
Figure 4 also shows auxiliary elements 28 that are used for fastening the blocking element 26 and/or guiding the control element 17 and the transmission element 15. In the embodiment of the invention shown in figure 4 the transmission element 15 is connected to a pivot point 29 of the swivel member 13. In this way the rotation of the swivel member 13 can be translated into an axial displacement of the transmission element 15.
In another embodiment of the invention, swivel member 13 can be arranged to comprise a further control abutment. The further control abutment can be arranged to axially displace transmission element 15 in the direction of the locking mechanisms when the transmission element 15 and the control abutment are brought into abutting contact as a result of the rotation of swivel member 13. When the one and other legs are in the active position, the rotation of swivel member 13 is caused by operating the manual operator 16 such that control element 17 is axially displaced in the direction of control abutment 25 and abutting contact of these elements occurs.
Figure 5 shows a side elevation of the hinge arrangement, wherein the control element 17 is in abutting relationship with the control abutment 25 of the swivel member 13. As a result of operating the manual operator 16, the control element 17 is axially displaced in the direction indicated by arrow 30, the swivel member 13 is rotated around the hinge axis 14 in the direction on arrow 31, and the transmission element 15 is axially displaced in the direction of arrow 32. This leads to unlocking of the locking mechanism 11 in the one leg 4. Leg section 8 can now be moved in an axial direction with respect to leg section 9 for adjusting the length of the one leg 4.
When the manual operator is returned to its initial position the above mentioned elements move in the opposite direction, which results in locking of the locking mechanism 11 in the one leg 4. Leg section 8 is then fastened and cannot be moved any more in an axial direction with respect to leg section 9.
Figure 6 shows a side elevation of the hinge arrangement, wherein the one leg 4 and the other leg 5 are aligned with respect to each other. The blocking element 26 is in a second active position in which the hinge arrangement 6 is blocked such that the angle (α) between the one and other legs 4, 5 of the support apparatus 1a; 1b is substantially 180°. As mentioned above, the first rotated position or the first set of rotated positions is defined by a sharp angle (α). This means that when the blocking element 26 is in the second active position the control abutment 25 of the swivel member 13 is not positioned opposite the control element 17 of the other leg 5. The operating mechanism is also arranged such that in this case the control element 17 and the transmission element 15 cannot be brought into direct contact with each other. As a result, the locking mechanism 11 of the one leg 4 cannot be unlocked or locked by operating the manual operator 16. In this case, operating the manual operator 16 only results in unlocking or locking the locking mechanism 11 of the other leg 5.
Figure 7 shows a front view of the hinge arrangement 6. The hinge arrangement 6 comprises essentially flat and parallel hinge plates 70, 71 which are rotatable with respect to each other around a hinge axis 14 that is arranged perpendicular with respect to side plates 72, 73 which are each connected to respectively the one leg 4 and the other leg 5. Figure 7 also shows that the swivel member 13 is rotatable around the hinge axis 14 and that it is contained within a circumferential rim 74, 75 of the hinge plates 70, 71.
Figure 8a shows a perspective view of two interconnected control arrangements according to the present invention in the case that two support apparatuses 1a, 1b have been applied in for example a ladder 2. By operating the manual operator 16 the pushing blocks 19 that are positioned on the rod 20 that interconnects the first and second support apparatuses 1a, 1b, are rotated. This results in a simultaneous axial displacement of the further transmission elements 18 in the direction of the locking mechanisms 11 of the other legs 5 and of the control elements 17 in the direction of the swivel members 13. Provided that the one and other legs 4, 5 are in a first rotating position, the control elements 17 are brought into abutting contact with the control abutments 25 and the swivel members 13 are rotated around hinge axis 14. This rotation results in an axial displacement of the transmission elements 15 in the direction of the locking mechanisms of the one legs 4. In this way the locking elements are unlocked and the leg sections 8 can be moved in an axial direction with respect to leg sections 9 for adjusting the lengths of all four legs individually. As mentioned above, when the manual operator 16 is returned to its initial position the elements of the operating mechanisms move in the respective opposite directions and the locking mechanisms 11 are simultaneously locked.
Figure 8b shows a perspective view of two interconnected control arrangements according to the present invention in the case that two support apparatuses 1a, 1b have been applied in for example a scaffolding or platform ladder 22. In this case, each support apparatus 1a; 1b comprises two swivel members 13 that are interconnected by an intermediate section 23 which in use of the scaffolding 22 is positioned substantially horizontally to enable level support e.g. of a person and/or of equipment. Simultaneously controlling the locking mechanisms 11 in the one leg 4 and the other leg 5 of the support apparatus 1a; 1b can be achieved by operating the manual operator 16 that is located at the other leg 5. As described above, operating the manual operator 16 results in simultaneous axial displacement in opposite directions of the control elements 17 and further transmission elements 18 in the other legs 5. The control elements 17 which are axially displaceable in the direction of the other swivel members 13 can be brought into abutting relationship with the control abutments 25 of the other swivel members 13 when the one and other legs 4, 5 are positioned with respect to each other such that a first rotated position or a position out of a first set of rotated positions is obtained. As a result of the abutting relationship between the control elements 17 of the other legs 5 and the control abutments 25 of the other swivel members 13, the other swivel members are rotated around the hinge axis 14. As the other and one swivel members 13, 13' are interconnected by the coupling element 24, such as a rod or a bar, a simultaneous and coupled rotation of these swivel members 13, 13' is achieved. As a result of the rotation of the one swivel members 13' the cooperating transmission elements 15 of the one legs 4 are axially displaceable such that the locking mechanisms 11 of the one legs 4 can be controlled. It is clear that operating the manual operator 16 located at the other leg 5 results in a simultaneous unlocking and locking of the locking mechanisms 11 of the one and other legs 4, 5 of the support apparatuses 1a, 1b comprising an intermediate section 23. Furthermore, from figure 8b it is clear that the one swivel members 13' do not comprise control abutments 25, such as the other swivel members 13 do. This is not strictly required as the one swivel member 13' only has to act as an element that displaces the transmission element 15 as a result of the displacement of coupling element 24, which is displaced by rotation of the other swivel member 13 when the manual operator 16 is operated and the one and other legs 4, 5 are positioned in a first rotated position or in a position out of a first set of rotated positions with respect to each other. Therefore, the coupling element 24 is connected to a pivot point 29 of the one swivel member 13' in the same way as is the case for transmission element 15.
Figure 9a shows a detailed side elevation of an embodiment of the control arrangement of the other leg 5 of the support apparatus 1a; 1b according to the present invention wherein the locking mechanism 11 is in the locked position. In the embodiment shown, the house 60 is integrated in leg sections 9 of the one and other legs 4, 5. At one end of the house 60, a sliding bar 33 is slidably received. The sliding bar 33 may slide in an axial direction. At an upper end of the sliding bar 33, a stop is provided, to limit the extension, i.e. downward movement, of the sliding bar 33. The sliding bar 33 is connected to leg section 8 that has a foot part 7 for stable placement of the ladder 2 in a used position. Around the sliding bar 33 a spring 44 is positioned. The spring extends between the outer side of the house 60 and the upper part of leg section 8. At the other end of the house 60, a further transmission element 18, such as a rod or a bar, is slidably received. In the house 60 a spring 43 is provided, thereby contacting one end of the transmission rod 18. More upwards, the further transmission rod 18 is also slidably received in an auxiliary element, such as a guiding block 28. An upper end of the transmission rod 31 engages a pushing block 19, that is connected to a rod 20 that interconnects the control arrangements of the support apparatuses 1a, 1b. The pushing block 19 and rod 20 may rotate around the centre line of the rod 20. It is possible that a corner of the pushing block 19 rests on a surface in a locked position of the locking mechanism 11. For instance, it may be possible that the lower right corner of the pushing block 19 rests on the guiding block 28, and/or that the upper right corner rests on the inner part of the leg section 9, in a locked position of the locking mechanism 11. In this way, rotation of the pushing block 19 in one direction is prevented. This ensures that only a small rotational movement of the pushing block 19, and thus a small rotational movement of the cooperating manual operator 16, is sufficient for unlocking the locking mechanism 11.
In the house 60, a cam 36 is connected to the further transmission rod 18 at a hinge point 51. The cam 36 may engage two catches 34, 35. One catch 34 is provided at an upper end of the cam, and one catch 35 is provided at a lower end of the cam 36. An upper side 61 of the cam engages catch 34, and a lower side 62 of the cam 36 engages catch 35. The cam 36 may be made in the shape of a butterfly, i.e. having two legs that extend round the sliding bar 33. Each catch 34, 35 has one side thereof positioned in a groove 52, 53 of the house 60. The catch 34, 35 may tilt, or rotate, in the house 60 around a rotation axis formed by the lengthwise direction of the groove 52, 53. It is noted that in the embodiment shown, the catch 34, 35 has no fixed axis of rotation within the house 60. The catch 34, 35 is not connected to the house 60, but may freely move in the house 60 and in the cavity 52, 53. The outer end of the catch may move in a horizontal plane. With this, fewer parts are needed, and thus the locking mechanism 11 may be simplified, without compromising a tight and safe locking of the two leg sections 8, 9.
Figure 9b shows a perspective view of a catch 34 element of the locking mechanism 11. The catch 34 has a cavity 40 formed therein. The sliding bar 33 of leg section 8 is slidably received in the cavity 40 of the catch 34 as can be seen in figure 9a. The cavity 40 may be cylindrical in shape, although other shapes are possible. The catch 34 has a stopping surface 47. The stopping surface 47 may comprise the inner shell of the cavity 40. Preferably, the stopping surface 47 includes the edge 45 of the cavity 40 with the outer surface 54 of the catch 34. At the bottom of the catch 34, a similar edge exists. Additionally, a second U-shaped cavity 49 is provided in the catch.
The operation of the locking mechanism 11 will be explained next. In a locked position, shown in figure 9a, the further transmission rod 18 is in an upward position, wherein hinge point 51 of the cam 36 is also lifted upwards. The outer surfaces of the cam 36 are designed to enable the catches 34, 35 to rotate or tilt towards the centre of the house 60. When tilted, different parts of the stopping surface 47 of the cavity 40 of a catch 34, 35 will engage the sliding bar 33. More specifically, at least the two edges 45 of the cavity 40 will engage the sliding bar 33. Hereby, parts of the two edges 45 on both sides of the cavity 40 will contact the sliding bar 33. The edges may press into the sliding bar. The edges may also cut into the sliding bar 33. This ensures that a high locking pressure is obtained, and prevents the relative movement of the two leg sections 8, 9 with respect to each other. The upper edge 45, and the lower edge 45 engage with parts that are facing each other. Therefore, opposite perimeter parts of the sliding bar 33 are engaged. This imposes a moment on the sliding bar 33. As a result, the sliding bar 33 is pressed to both the house 60 and to the stopping surfaces 47. The sliding bar 33 is thus jammed by the catch 34 and the house 60. Each contact point will yield static friction, which prevents the sliding bar 33 from sliding in the house 60. It will therefore be impossible for the sliding rod to move, and thus axial movement of the leg is impossible.
It is noted that only a single catch 34 may be sufficient in order to fix the sliding bar 33. The additional catch 35 is positioned longitudinally from the first catch 34. This additional catch 35, in combination with the first catch 34 ensures a tight fix. It can be seen in figure 9a that the catches 34, 35 tilt in opposite directions. In this way, prevention of axial movement in both directions is ensured. Also, a tight fix is assured.
The springs 38, 39 that are provided next to the catches 34, 35 also ensure that the catches 34, 35 are rotated or tilted towards the centre of the house 60. The springs 38, 39 ensure that the catches 34, 35 are pushed towards a locked position. The springs 38, 39 also ensure an increased engagement of the stopping surfaces 47 on the sliding bar 33. In this way, a tight and safe fix of the sliding bar 33 in the locking mechanism 11 is achieved. In the embodiment shown, the springs are positioned parallel to, and around the sliding bar 33 of leg section 8. Other positions are possible however. Other elements for biasing the catch towards a locking position are also possible. For example, a spring that is positioned near to the further transmission element 18, and connected to botch catches 34, 35, may be used to pull the two catches 34, 35 towards each other, thus biasing the two catches towards a locking position.
Figure 9c shows a detailed side elevation of the embodiment of the control arrangement of the other leg 5 of the support apparatus 1a; 1b according to the present invention wherein the locking mechanism 11 is in the unlocked position.
Unlocking the locking mechanism 11 may be done as follows. By operating the manual operator 16, the pushing block 19 and rod 20 rotate and the further transmission element 18 is axially displaced in a downward direction. As a result, the hinge point 51 of the cam 36 will also move down. The cam 36 and house 60 are arranged such that this downward movement will result in rotation of the cam 36 around rotation point 51. The cam 36 is arranged such that the combined movement results in simultaneously tilting the two catches 34, 35 from a locking position to an open position. The movement of the cam 36 will lead to movement of the upper and lower surfaces of the cam 36, resulting in a tilting movement of both catches 34, 35 towards an outside part of the house 60. As a result, the stopping surface 47 of the cavity 40 will then be positioned at a certain distance from the sliding bar 33, enabling movement of the sliding bar 33 within the house 60. In this way, the other leg 5 of the ladder 2 may be extended or shortened in an axial direction.
It is noted that in a locked position of the locking mechanism 11, the cain 36 may freely rotate around hinge point 51. It is possible that the outer surfaces of the cam 36 are not in direct contact with the catches 34, 35. In that case, movement of the further transmission element 18 may be necessary to bring the outer surfaces of the cam 36 into contact with the catches 34, 35, enabling movement of the catches 34, 35 towards an open position. In this way, the locking mechanism 11 may only be brought to an open position by actual movement of the further transmission element 18. This ensures that the user has to unlock the locking mechanism 11 intentionally, and prevents accidental unlocking of the locking mechanism 11.
In an unlocked position, a longitudinal axis of the cavity 40 extends parallel to the sliding bar 33. This ensures that the area through which the sliding bar 33 may be slided is maximal, i.e. that there is a maximal aperture for the sliding bar 33. Accidental lock-ups may be prevented with this.
In an unlocked position, the spring 44 around the sliding bar 33 biases the extendible leg section 8 towards an extended position. Preferably, the force of the spring is designed such that it balances the weighing force of the object to be supported. This way, releasing the locking mechanism 11 will only result in the extendable leg being extendable, without actually sliding within the house 60. Releasing the locking mechanism 11 therefore does not result in an active shortening of the extendible leg due to gravitational forces. When multiple legs are used, the force of each spring is chosen such that the combined forces of the springs balance the weighing force of the object to be supported. The multiple springs may each have a different spring force, dependent on the weight distribution of the object to be supported. An object, such as a ladder 2, provided with a number of support apparatuses according to this embodiment, is relatively easy to position in any desired fashion. The effort needed to change the orientation of the object is relatively small, since the object is more or less self-supported by the biased springs.
When the manual operator 16 is returned to its initial position, the actions of the springs 38, 39 near the catches 34, 35, as well as the actions of the spring 43 near the further transmission element 18, will result in an axial displacement in an upward direction of the further transmission element 18, thereby locking the locking mechanism 11.
Figure 10a shows a perspective view of two interconnected support apparatuses according to the present invention wherein the two operating mechanisms comprise pulling members 80 to lock and unlock the locking mechanisms 11' located on the one legs 4 of the support apparatuses. The pulling members 80 are guided by swivel members 13" that are rotatable around a hinge axis 14 of the hinge arrangement 6. Contrary to swivel members 13, the swivel members 13" do not need to comprise a control abutment 25. When the one and other legs 4, 5 respectively of the support apparatuses are in a first rotated position or in a set of first rotated positions with respect to each other as is shown in this figure, operating the manual operator 16 will allow simultaneous unlocking and unlocking of the locking mechanisms 11, 11'. It is noted that locking mechanism 11' has to be constructed such that movement of the manual operator 16 out of its rest position results in the application of a pulling force on locking mechanism 11' by pulling member 80. As a result, locking mechanism 11' is unlocked and the length of the one leg 4 can be adjusted. When the manual operator 16 is returned to its rest position locking mechanism 11' is locked and the length of the one leg 4 is fixed.
Figure 10a furthermore shows a tensioning device 81 that is arranged for tensioning the pulling members 80 such that operating the manual operator 16 allows simultaneous operation of the locking mechanisms 11, 11' of the respective legs 4, 5 when these legs are in a first rotated position or in a first set of rotated positions with respect to each other. When the one and other legs 4, 5 respectively are not in the aforementioned positions with respect to each other the tensioning device 81 does not allow unlocking of the locking mechanisms 11' located at the one legs 4.
Figure 10b shows a perspective view of two interconnected support apparatuses comprising intermediate sections 23 that have been applied in a scaffolding or platform ladder, wherein the two operating mechanisms comprise pulling members 80 to lock and unlock the locking mechanisms 11' located on the one legs 4 of the support apparatuses.
Figure 11 shows a side elevation of a hinge arrangement 6 according to the present invention, showing a pulling member 80 that is arranged around a swivel member 13" that is rotatable around a hinge axis 14 of the hinge arrangement 6 when the one and other legs 4, 5 respectively of the support apparatus are in a first rotated position with respect to each other. This figure shows that swivel member 13" does not have a control abutment 25 as swivel members 13 do.
Variations on the embodiments shown are imaginable, without diverting from the main notion of the invention. It will be clear that the invention is described by using preferred embodiments. The invention is not intended to be limited to these embodiments. The scope of protection sought is determined by the following claims within the scope of which many modifications can be envisaged.

Claims

Support apparatus, comprising legs (4, 5) which at one end thereof are connected to each other by means of a hinge arrangement (6) and which at the other end thereof comprise respective support feet (7), said legs (4, 5) each comprising leg sections (8, 9) which are adjustable with respect to each other for providing an adjustable leg length, a control arrangement being provided comprising a locking mechanism (11, 11') for locking respectively unlocking the leg sections (8) of each leg (4, 5) as well as an operating mechanism allowing simultaneous operation of the locking mechanisms (11, 11') of respective legs (4, 5), characterized in that elements of the operating mechanism are at least partly integrated in, or are at least partly located at, the hinge arrangement (6).
Support apparatus according to claim 1, wherein the operating mechanism comprises at least one swivel member (13) which is rotatable with respect to a hinge axis (14), as well as a transmission element (15) which cooperates with said swivel member (13) and with the locking mechanism (11) of one of the legs (4, 5) providing control of said locking mechanism (11) upon rotation of the swivel member (13).
Support apparatus according to claim 2, wherein a control element (17) is provided for controlling the at least one swivel member (13), as well as a manual operator (16), said control element (17) providing rotation of the swivel member (13) upon operation of the manual operator (16), said control element (17) and manual operator (16) being located at the other (5) of the legs.
Support apparatus according to claim 3, wherein a further transmission element (18) is provided at said other leg (5), said further transmission element (18) being operable by the manual operator (16) and providing control of the locking mechanism (11) of the other leg (5).
Support apparatus according to any of claims 2-4, wherein the transmission element (15) of said one leg (4) is hingedly connected to the at least one swivel member (13).
Support apparatus according to any of claims 3 or 4, wherein a swivel member (13) has a control abutment (25) that is located opposite the control element (17) of said other leg (5) in a first rotated position or in a first set of rotated positions of the legs (4, 5) with respect to each other and which is remote or removed from said control abutment (25) in other rotated positions of the legs (4, 5), so as to bring the control element (17) in abutting relationship with the control abutment (25) of said swivel member (13) while the latter is in the first rotated position or in the first set of rotated positions.
Support apparatus according to claim 6, wherein the legs (4, 5) are directly connected to each other through a hinge arrangement (6), the transmission element (15) of said one leg (4) and the control abutment (25) for cooperation with the control element (17) of the other leg (5) being associated with one and the same swivel member (13).
Support apparatus according to claim 6, wherein an intermediate section (23) is provided and the legs (4, 5) are connected to opposite ends of said intermediate section (23) through respective hinge arrangements (6), said hinge arrangements (6) each being provided with a swivel member (13, 13'), said swivel members (13, 13') being interconnected through a coupling element (24) allowing simultaneous and coupled rotation of said swivel members (13, 13'), the transmission element (15) of said one leg (4) being connected to the respective swivel member (13') and the control abutment (25) being arranged on the other swivel member (13).
Support apparatus according to any of the preceding claims, wherein blocking elements (26) are provided which are displaceable between an active position in which the legs (4, 5) are blocked against rotation with respect to each other at a sharp angle (α), and an inactive position allowing rotation of the legs (4, 5) with respect to each other.
Support apparatus according to claim 9 when depending on any of claims 6-8, wherein the first rotated position or the first set of rotated positions is defined by said sharp angle (α).
Support apparatus according to claim 9 when depending on any of claims 6-8, wherein the blocking elements (26) have a second active position in which the legs (4, 5) are aligned with respect to each other.
Support apparatus according to any of the preceding claims, wherein each hinge arrangement (6) comprises essentially flat and parallel hinge plates which are rotatable with respect to each other around a hinge axis (14) perpendicular with respect to said plates which are each connected to a respective leg (4, 5), the swivel member (13, 13', 13") being rotatable around said hinge axis (14) as well.
Support apparatus according to claim 12, wherein at least one of the hinge plates has a circumferential rim within which the swivel member (13, 13', 13") is contained.
Support apparatus according to claim 1, wherein the operating mechanism comprises a pulling member (80) that extends between a locking mechanism (11') located on the one leg (4) and a manual operator (16) located on the other leg (5) and/or between a locking mechanism (11) and a manual operator (16) both located on the other leg (5).
Support apparatus according to claim 14, wherein the operating mechanism comprises a pulling member (80) that extends between a locking mechanism (11') located on the one leg (4) and a manual operator (16) located on the other leg (5) and a further transmission element (18) that extends between said manual operator (16) and a locking mechanism (11) located on the other leg (5).
Support apparatus according to claim 14 or 15, wherein operating the manual operator (16) allows simultaneous operation of the locking mechanisms (11, 11') of the respective legs (4, 5) via the pulling member (80) and possibly the further transmission element (18) when these legs are in a first rotated position or in a first set of rotated positions with respect to each other.
Support apparatus according to any of claims 14-16, wherein the pulling member (80) is movable around a hinge axis (14) of the hinge arrangement (6).
Support apparatus according to any of claims 14-17, wherein the pulling member (80) is a cable.
Support apparatus according to any of claims 14-17, wherein the pulling member (80) is a chain.
Support apparatus according to any of claims 14-17, wherein the pulling member (80) is a belt.
Support apparatus according to any of claims 14-20, wherein the legs (4, 5) are directly connected to each other through the hinge arrangement (6).
Support apparatus according to any of claims 14-21, wherein an intermediate section (23) is provided and the legs (4, 5) are connected to opposite ends of said intermediate section (23) through respective hinge arrangements (6).
Support apparatus according to any of claims 14-22, wherein a tensioning device (81) is provided that is arranged for tensioning the pulling members (80) such that operating the manual operator (16) allows simultaneous operation of the locking mechanisms (11, 11') of the respective legs (4, 5) when these legs are in a first rotated position or in a first set of rotated positions with respect to each other.
Foldable ladder or stepladder or scaffolding, comprising a first as well as a second support apparatus (1a, 1b) according to any of the preceding claims which are arranged parallel to each other and which are interconnected by means of parallel and evenly spaced beams (3), wherein the control arrangements of both support apparatuses (1a, 1b) are interconnected allowing simultaneous control of all four legs (4, 5).
Foldable ladder or stepladder or scaffolding according to claim 24, wherein activating elements (16) are provided which are operable to manually activate the control arrangement of at least one of the support apparatuses (1a, 1b).