Sliding gate.
The present invention relates to a sliding gate having a motor driven gate portion which can be shifted horizontally in order to close and expose an opening, said gate portion in the closed position protruding from a support portion journalled for movement on a base and which comprises a rail having a length being approximately equal to the length of the gate portion.
Examples of such sliding gates appear among else from DE A1 3432273 and 4407122 and EP patent application No. 0711898.
Such gates will normally have lateral support at the top, at least in one place, appropriately immediately by the side of the opening by which the gate is installed. The lateral support may be formed of one or more uprights having support wheels which are in engagement in a high position on the gate portion, and the upright or uprights may simultaneously form the site for installing of the motor which drives the gate portion.
A reason why such gates without support beyond the support portion are used is that for instance rollers rolling along a track in the base, such as a rail, may cause problems due to snow, ice and soil, sand and gravel.
The sliding gate appearing from EP patent application No. 0711898 comprises a lattice portion forming the gate portion, and a support portion firmly connected to the gate portion. A lower rail extends in the entire length of the lattice portion and the support portion and is journalled on rollers in order to be moved therewith. The support portion is approximately half as long as the gate portion. When the gate is closed, the support portion is situated immediately outside of the opening which is closed by the gate portion. When the gate is open, the support portion has been shifted such a distance that the gate portion is immediately outside of the exposed opening. In other words, the support portion has been shifted approximately twice its own length relatively to the closed position, and protrudes a distance from the exposed opening which is approximately 1 ,5 times the width of the opening. If this width is for instance 6 m, the distance to which the support portion protrudes is approximately 9 m outside of the opening when the gate is fully open. This limits the use of such gates, because not all places exhibit available space for such shifting of the support portion. Another drawback is that the gate has a large total length, in the above example approximately 9 m, being
the sum of the length of the gate portion and the support portion, and transportation of the gate is expensive. The problem associated with the large total length may only to some degree be reduced by making the support portion shorter. This solution has the consequence that the distance between the rollers which are to take up the moment due to the weight of the gate portion is reduced, and the load on the rollers and the gate portion will be increased.
By the present invention a solution of this problem has been provided.
A sliding gate according to the invention is characterized by the features appearing from the succeeding claim 1.
In a sliding gate according to the invention the support portion will, when the gate is open, be shifted a distance mainly corresponding to the length of the gate portion, which means that the support portion does not occupy substantially more space than the gate portion. Thereby, it is made possible to install the gate in places which can mainly only accommodate the gate portion i an open position.
The support portion comprises a lengthwisely shiftable, horizontal rail being approximately as long as the gate portion, and which during the opening and closing movement is moved with approximately half the speed of the gate portion. When the gate is open, the rail extends mainly below the entire gate portion and gives support to that. During the closing movement the gate portion is moved to a fully closed position, and the rail is simultaneously moved mainly half of this distance, approximately to or slightly past the middle of the gate portion. The rail may be formed as a double journalling rail, giving room for two sets of wheels which can run independently of each other. The rail is all the time journalled for rolling on a firm base at least on two places, and journals the gate portion for rolling, whereby this may be shifted relatively to the rail. In the closed position of the gate portion the center of gravity of the gate portion may be situated within the free end of the rail. This is, however, not critical, because the set of wheels prevents rocking of the gate portion, except from a very small rocking movement due to a clearance between the set of wheels and the rail.
Thereby, the gate portion is stably supported. In order to prevent extra strain on the sets of wheels when the gate portion is in the closed position, for instance when persons
apply a load on the gate portion, the gate portion may for instance enter a support with its free end when the gate portion is in its fully closed position.
In order to achieve that the gate portion is moved with a speed being twice the speed of the rail, two motors may be used, which by driving wheels drive the gate portion and the rail individually, whereby the rail is driven with a speed being the half of the speed of the gate portion. The driving may take place through toothed wheels against toothed racks, chain wheels against chains or friction wheels against rolling surfaces, respectively, whereby one toothed rack, one chain or one rolling surface, respectively, are situated along the rail. The motors have to be started and stopped simultaneously. If the driving wheels are of the same size, the rail motor must have a rotational speed being the half of that of the gate portion motor. An alternative is to use only one motor, which drives two driving wheels, of which the gate portion driving wheel has an effective diameter being twice of that of the rail motor. Two such driving wheels may be formed integrally.
The invention will in the following be explained more detailed, by means of examples shown on the accompanying drawings.
Fig. 1 shows a motor driven sliding gate according to the invention, in a closed position.
Fig. 2 shows the gate of Fig. 1 in a half closed position.
Fig. 3 shows the gate of Figs. 1 and 2 in a fully ope n position.
Fig. 4 shows a segment in the area of the drive unit, seen transversely of the gate.
Fig. 5 shows the area of the drive unit, seen along the gate.
Fig. 6 shows the area of the drive unit, seen from above.
The Figs. 1 - 3 are described as a whole.
The Figs, show a sliding gate having a gate portion 1 , which can be shifted on a rail 2 and be supported laterally by two uprights 3, between which the gate portion 1 can be moved. The gate portion 1 is shown as a lattice gate, with rods 12, without this constituting any limitation. A drive unit 4 with a motor is situated at the uprights, and may be installed on a bracket fastened thereto. To the gate portion 1 is fastened a longitudinally extending toothed rack 5, and to approximately one half of the rail 2 is fastened a toothed rack 6. The rail 2 may roll on two stationary pulleys 7 and 8. The pulley 7 is shown fastened to the base, while the pulley 8 is shown installed on one of
the' uprights 3. On the gate portion 1 are installed two pulleys 9 and 10 which can roll along the rail 2. The rail 2 may have a cross sectional shape as shown in Fig. 5.
The motor in the drive unit 4 drives the rail 2 with approximately half of the speed with which it drives the gate portion 1. Thus, during opening of the gate portion 1 from the position shown in Fig. 1 , the gate portion 1 and the toothed rack 5 will move approximately twice as fast as the rail 2, and when the gate portion 1 is fully open, as shown in Fig. 3, the rail 2 has moved such that one end of the rail 2 is situated at the uprights 3, while the other end is situated at the end of the gate portion 1 remotest from the uprights 3. Thereby, the rail 2 occupies the same space in the longitudinal direction as the gate portion 1 when in its open position.
The area near the drive unit will in the following be explained with reference to the Figs. 4 - 6.
The Figs, show uprights 3 which carry a drive unit 4 with a motor. On the gate portion 1 and the rail 2 are mounted toothed racks 5 and 6. Fig. 5 shows how the cross section of the rail 2 may be shaped, i.e. as some kind of an S having approximately right angles, whereby are formed two longitudinal channels being open towards opposite sides. In the lower half of the rail 2 are mounted pulleys 9 and 10 journalled for rotation at the bottom of the gate portion 1 , and in the upper half of the rail 2 are mounted pulleys 7 and 8 being stationary. In the embodiment shown are formed beads inside the rail 2, and the pulleys 7 and 8 have a corresponding rolling track, whereby a secure guiding is present between the pulleys 7 and 8 and the rail 2.
On the drive shaft of the motor is mounted a driving toothed wheel 11 , being a double toothed wheel having two toothings. The toothing having the largest diameter drives the gate portion 1 via the toothed rack 5, while the toothing having the smallest diameter drives the rail 2 via the toothed rack 6. When the toothing which drives the gate portion 1 has twice as large effective diameter as the toothing driving the rail 2, the gate portion will move twice as fast as the rail 2, as explained in connection with the Figs. 1 - 3.
As mentioned, the drive wheels may be something else than toothed wheels, such as chain wheels or wheel having a friction coating, for rolling along surfaces on the gate portion and the rail.
It will be appreciated that more than two pulleys 7 and 8 on which the rail 2 rolls and more than two pulleys 9 and 10 on which the gate portion 1 rolls may be provided. In al positions of the gate portion 1 the pulleys will prevent rocking of the gate portion 1. Moreover, the rail 2 may be shaped differently than shown. It must have two separate tracks for the pulleys, whereby these can pass each other.
Further, it is possible to construct the gate portion 1 and the rail 2 as divisible units, which for instance may be divided at the middle, in order to reduce the length of the units for transportation.