Mechanism for adjusting distance between first and second support members

Abstract

 A mechanism for adjusting distance between a first and a second support member (7, 8), preferably an elevating mechanism for an elevating table, and of the type with two-part legs (3) in pairs, each including a first upper arm (5) and a first lower arm (6) that each are connected with a support part (7 and 8, respectively) at one end and which are mutually connected by a first articulated joint (10) at their second ends. The two legs are mutually connected with a spindle (12) connected by threaded bushings (11) associated with each of the first articulated joints, producing a reduction of the angle between the first upper arm and the first lower arm by rotation of the spindle in one direction and increase of the angle by rotation of the spindle in the other direction, in order thereby to reduce or to increase the distance between the support members. A second upper arm (13) and a second lower arm (14) are provided for each leg (3), the second arms being connected at their first ends with the first upper arm and the first lower arm, respectively, at a position between the outer ends thereof, and which at the second ends are interconnected by a second articulated joint (21) which is provided farther from each other than the first articulated joints, and that a bearing (22) for the spindle is provided at the second articulated joint. The design provides a stable support, while at the same time being production- and mounting-friendly.

Description

Field of the Invention

[0001] The present invention concerns a mechanism for adjusting distance between a first and a second support member, preferably an elevating mechanism for an elevating table, and of the type two-part legs in pairs, each including a first upper arm and a first lower arm that each are connected with a support part at one end and which are mutually connected by a first articulated joint at their second ends, and where the two legs are mutually connected with a spindle connected by threaded bushings associated with each of the first articulated joints, producing a reduction of the angle between the first upper arm and the first lower arm by rotation of the spindle in one direction and increase of the angle by rotation of the spindle in the other direction, in order thereby to reduce or to increase, respectively, the distance between the support members. The support members may be a support upon a floor and against a working plate or frame for a working platform which is to be raised and lowered relative to the floor.

[0002] By the terms upper and lower as used in the present application, reference is made to an application with the legs largely vertically oriented. However, the mechanism may also be used with other orientations. It may, for example, be used for providing distance between two supporting plates for application with vertical orientation, e.g. for supporting shuttering in excavations.

Background of the Invention

[0003] Various types of mechanisms and frames for use in adjusting the distance between two support members, e.g. for lifting and lowering a platform, e.g. a working table. A mechanism of the type mentioned in the introduction is known from US 2002/013618. It is intended to produce a movement where a parallelism is maintained between a supporting part and a movable part, e.g. a working table. In practice, this mechanism appears to be unfavourable as it has insufficient stability in order to be used in the raised position, irrespectively whether this is a fully elevated position or a partially elevated position.

[0004] Furthermore, the mechanism is unfavourable as the legs are folded outwards, and are thus required to locate at a position some distance within under a tabletop. This also produces instability, causing that the tabletop cannot be loaded at the corners as a risk of tilting of the table is present.

Object of the Invention

[0005] It is the purpose of the present invention to indicate a mechanism where the above drawbacks are relieved and at the same time to provide an adjusting mechanism, preferably an elevating mechanism for an elevating table, which provides a stable support and which is production- and mounting-friendly at the same time.

Description of the Invention

[0006] This is achieved according to the present invention with a mechanism of the type specified in the introduction, which is peculiar in that a second upper arm and a second lower arm are provided for each leg, the second arms being connected at their first ends with the first upper arm and the first lower arm, respectively, at a position between the outer ends thereof, and which at the second ends are interconnected by a second articulated joint which is provided farther from each other than the first articulated joints, and that a bearing for the spindle is provided at the second articulated joint.

[0007] Using a leg with second upper and lower arms enables establishing stable legs and disposition of the spindle between the two legs engaging both first and second sets of arms provides a very stable support. With a construction of the legs including two sets of arms, it becomes possible to dispose the legs right at the ends of a working plate or similar which is disposed upon the support members, and to let one set of arms pivot in against the second leg by maintaining the position of the spindle in the bearing. This may e.g. be effected by letting a locking ring interact with a ring-shaped cutout so that the spindle is retained against displacing relative to the bearing. At the same time, support may be maintained approximately at the extreme ends of the working plate.

[0008] As the individual elements at the two legs can be made identical, the mechanism is furthermore a production- and mounting-friendly design.

[0009] According to a further embodiment, the mechanism according to the invention is peculiar in that the two legs are interconnected by a crossbar connected with the articulated joints. Thus not only the spindle but also the crossbar contribute to provide stability. This is particularly an advantage when the crossbar is connected to both sets of arms. The crossbar will preferably be secured to the articulated joints, which include the bearings and will be displaceably connected to the articulated joints that include the threaded bushings. The crossbar may hereby function as a guide for the displacement of the threaded bushing during the mutual pivoting of the arms, while the bearings remain in a securely retained position.

[0010] According to a further embodiment, the mechanism according to the invention is peculiar in that each arm includes two parallel arm elements. This provides increased stability. The arm elements may be disposed with mutual spacing, which is desired so that arm elements can be provided approximately under the corners of a working plate or similar placed on the support members of the mechanism.

[0011] According to a further embodiment, the mechanism according to the invention is peculiar in that the crossbar includes two parallel crossbar elements. This provides better rigidity and at the same time the articulated joints can be fastened between the two crossbar elements, thereby kept fixed in a particularly secure way without any risk of twisting, even under heavy load on a working plate placed on the mechanism.

[0012] According to a further embodiment, the mechanism according to the invention is peculiar in that one end of the spindle includes a left-handed thread for interacting with the threaded bushing in one leg, and that the other end of the spindle includes a right-handed thread for interacting with the threaded bushing in the other leg. This is a simple way of establishing the simultaneous reduction/increasing of the angle of the arms in each of the two sets of legs by rotating the spindle.

[0013] According to a further embodiment, the mechanism according to the invention is peculiar in that the support members include a support for disposition on a floor and an support for carrying a working platform, working plate or similar. This is particularly advantageous when the mechanism is used as support structure in an elevating table or as a support structure in an elevating platform, e.g. for use in a scaffold.

[0014] According to a further embodiment, the mechanism according to the invention is peculiar in that the second upper arm and the second lower arm are connected at about the centre of the first upper and lower arms. Hereby an advantageous geometry is obtained with optimal support where all arm elements can be disposed under a working plate, even when the legs are disposed in folded condition. At the same time, collapsing into a very flat construction may be effected, with the arm elements lying in parallel and largely in contact with each other.

[0015] By using four-edged pipes of about 40 x 40 mm, it has appeared possible to attain a total height in the lowered condition of about 200 mm and a total height of about 1200 mm in raised condition for a mechanism which is about 1200 mm in length and where the legs are disposed at each end of the mechanism. Each of the first arms has a length of 560 mm and each of the second arms has a length of 280 mm. The connection between the first and second arms will be provided at the centre between the ends of the first arms.

[0016] According to a further embodiment, the mechanism according to the invention is peculiar in that the bearing at the second articulated joint is adapted for securing at the outer ends of the spindle so that the second articulated joint and the support members in a leg are situated largely in the same plane during the changing of the distance between the support members. The legs may hereby be disposed at a position adjacent to the ends of a tabletop so that the tabletop may be loaded at the extreme ends without any risk of tilting.

[0017] According to a further embodiment, the mechanism according to the invention is peculiar in that at least one end of the threaded rod is provided with means for engaging drive means in the form of drive motor, crank handle, ratchet wrench or similar. If a fastened nut or Allen screw is used, then a standard drilling machine with suitable key insert can be used for lifting and lowering a tabletop on a support structure.

[0018] According to a further embodiment, the mechanism according to the invention is peculiar in that a pair of first upper arm elements are disposed in the same plane as a pair of second lower arm elements, and that a pair of second upper arm elements are disposed in the same plane as a pair of first lower arm elements. This provides a compact design and simultaneously a rigid construction, since the arms may be disposed in planes close to each other. The risk of twisting in the construction is also minimised hereby, even at great loads.

[0019] According to a further embodiment, the mechanism is provided with a support at one end of the mechanism. By elevation from fully lowered position, usually a large moment is required because of the folded state of the legs. The support, which has greater height than the height of the legs in the fully collapsed condition, ensures that the mechanism is not to carry the weight of the entire construction at the initial elevating. A substantially smaller moment may thus be applied for the initial elevation.

Description of the Drawing

[0020] The invention will then be explained in more detail with reference to the accompanying drawing, where

Fig. 1

shows a perspective view of a mechanism according to the invention in the form of a support structure for an elevating table in a raised position;

Fig. 2

shows a perspective view of the support structure shown in Fig. 1 in a lowered position;

Fig. 3

shows a side view corresponding to Fig. 1;

Fig. 4

shows a side view corresponding to Fig. 2;

Fig. 5

shows a perspective view of a further embodiment of a mechanism according to the invention in the form of a support structure for an elevating table in partly raised position;

Fig. 6

shows a side view corresponding to Fig. 5;

Fig. 7

shows a perspective view of an elevating table in partly raised condition with a support structure of the type shown in Figs. 1 - 4; and

Figs. 8 - 9

show side views of an alternative embodiment of the mechanism according to the invention in lowered and partly raised positions.

Detailed description of the invention

[0021] The same or identical elements will be designated by the same reference numerals in the subsequent figures. Therefore, no explanation of all details will be given in connection with each Figure.

[0022] A mechanism according to the invention is shown in Figs. 1 - 4 in the form of a support structure I for an elevating table 2 which is shown in Fig. 7. The support structure 1 includes two legs 3 for disposition at each end of a tabletop 4 and fastened thereto by means of not shown fastening means.

[0023] Each leg 3 is two-part and includes a first upper arm 5 and a first lower arm 6. The first upper arm 5 is formed by two parallel arm elements 5a and 5b and the first lower arm 6 is formed by two parallel arm elements 6a and 6b.

[0024] Each of the arms 5 is connected to a transverse support rod 7 which is fastened to both arm elements 5a and 5b and intended for supporting the tabletop 4. Each of the arms 6 is connected to a transverse support rod 8 which is fastened to both arm elements 6a and 6b and intended for being supported by a floor. The support rod 8 may optionally be provided with contact blocks 9 as shown in Fig. 7.

[0025] Each of the first upper arms 5 and the first lower arms 6 are connected with a first articulated joint 10 enabling mutual pivoting of the upper arm 5 and the lower arm 6.

[0026] In connection with the first articulated joint 10, at each leg 3 there is provided a threaded bushing 11 engaging a threaded spindle 12. The threaded bushings 11 are connected with the spindle 12 which has a first half 12a with left-handed thread and a second half 12b with right-handed thread, which are connected by threaded bushings associated with each of the first articulated joints 10, producing a reduction of the angle between the first upper arm 5 and the first lower arm 6 by rotating the spindle 12 in one direction and increase of the angle by rotating the spindle 12 in the other direction, in order thereby to reduce or to increase the distance between the support members 7 and 8.

[0027] At each leg 3 there are provided a second upper arm 13 and a second lower arm 14, the second arms being connected at their first ends 15 and 16, respectively, with the first upper arm 5 via an articulated joint 19 and the first lower arm 6 via an articulated joint 20, respectively, at a position between the outer ends of the first upper arm 5 and the first lower arm 6, respectively.

[0028] The second upper arm 13 and the second lower arm 14 are interconnected at the other ends 17 and 18, respectively, by a second articulated joint 21, and provided farther from each other than the first articulated joints 10.

[0029] The second upper arm 13 is formed by two parallel arm elements 13a and 13b, and the second lower arm 14 is formed by two parallel arm elements 14a and 14b.

[0030] At the second articulated joint 21, a bearing 22 for the spindle 12 is provided. The bearing 22 is provided in rotational connection with the spindle 12 at each end, and is designed so that the spindle 12 may rotate freely but may not be displaced in relation to the bearing 22.

[0031] In the embodiments shown in Figs. 1 - 4 and 7, a crossbar 23 is provided between the legs 3, connected with the articulated joints 10 and 21 and including two parallel crossbar elements 23a and 23b which are disposed in parallel with the spindle 12 and at positions above and below the spindle 12.

[0032] As it particularly appears from Figs. 2 and 7, the first pair of upper arm elements 5a, 5b are disposed in the same plane as the second pair of lower arm elements 14a, 14b, and the second pair of upper arm elements 13a, 13b are disposed in the same plane as the first pair of lower arm elements 6a, 6b. Hereby a stable construction is achieved. As the individual elements at the two legs are identical, the mechanism is a production- and mounting-friendly design at the same time. The spindle 12 is provided at the end with a hexagonal profile 28 that constitutes means for engaging drive means in the form of drive motor, crank handle, ratchet wrench or similar.

[0033] The embodiment shown in Figs. 5 and 6 is primarily distinguished by not having a crossbar disposed in parallel with the spindle 12. At each leg 3', separate arms 5' and 6' are provided at each corner. These are interconnected by crossbars 24 and 25, respectively, which at their centre support further arms 13' and 14'. The support members are here provided by an upper frame 26 for supporting a working platform, tabletop or similar, and a lower frame 27 for disposition on a floor. The function would be analogous to the above described embodiment.

[0034] The embodiment shown in Figs. 8 and 9 differs from the above described by being provided with a support 29 at one end of the mechanism. When raising from fully lowered position, usually a large moment is required because of the folded state of the legs 3. The support ensures that at initial raising, the mechanism is not to carry the weight of the entire construction, and therefore a considerably lesser moment may therefore be used for the initial lift.

[0035] The height of the support 29 is greater than the height of the collapsed legs. Therefore, initial raising is obtained when there is no load on the legs 3 at the left side, from the situation shown in Fig. 8 to the situation shown in Fig. 9 where the left leg 3 touches the base. The support may be formed by two legs at each side, or may be a throughgoing plate extending across the width of the mechanism.

Claims

1. A mechanism for adjusting distance between a first and a second support member, preferably an elevating mechanism for an elevating table, and of the type with two-part legs in pairs, each including a first upper arm and a first lower arm that each are connected with a support part at one end and which are mutually connected by a first articulated joint at their second ends, and where the two legs are mutually connected with a spindle connected by threaded bushings associated with each of the first articulated joints, producing a reduction of the angle between the first upper arm and the first lower arm by rotation of the spindle in one direction and increase of the angle by rotation of the spindle in the other direction, in order thereby to reduce or to increase, respectively, the distance between the support members, characterised in that a second upper arm and a second lower arm are provided for each leg, the second arms being connected at their first ends with the first upper arm and the first lower arm, respectively, at a position between the outer ends thereof, and which at the second ends are interconnected by a second articulated joint which is provided farther from each other than the first articulated joints, and that a bearing for the spindle is provided at the second articulated joint.

2. Mechanism according to claim 1, characterised in that each arm includes two parallel arm elements.

3. Mechanism according to claim 1 or 2, characterised in that the two legs are interconnected by a crossbar connected with the articulated joints.

4. Mechanism according to claim 1, 2 or 3, characterised in that one end of the spindle includes a left-handed thread for interacting with the threaded bushing in one leg, and that the other end of the spindle includes a right-handed thread for interacting with the threaded bushing in the other leg.

5. Mechanism according to any preceding claim, characterised in that the support members include a support for disposition on a floor and an support for carrying a working platform, working plate or similar.

6. Mechanism according to any preceding claim, characterised in that the second upper arm and the second lower arm are connected at about the centre of the first upper and lower arms.

7. Mechanism according to any preceding claim, characterised in that the bearing at the second articulated joint is adapted for securing at the outer ends of the spindle so that the second articulated joint and the support members in a leg are situated largely in the same plane during the changing of the distance between the support members.

8. Mechanism according to any preceding claim, characterised in that at least one end of the threaded rod is provided with means for engaging drive means in the form of drive motor, crank handle, ratchet wrench or similar.

9. Mechanism according to any of claims 2 - 8, characterised in that a pair of first upper arm elements are disposed in the same plane as a pair of second lower arm elements, and that a pair of second upper arm elements are disposed in the same plane as a pair of first lower arm elements.

10. Mechanism according to any of claims 3 - 9, characterised in that the crossbar includes two parallel crossbar elements.

Drawing