Technical field

The present disclosure relates to a boom barrier for blocking vehicular or pedestrian access and a method for operating a boom barrier. More specifically, the disclosure relates to a boom barrier for blocking vehicular or pedestrian access and a method for operating a boom barrier as defined in the introductory parts of the independent claims.

Background art

Automatic boom barriers are used for many applications for restricting access to a physical area for vehicles and/or pedestrians. They are widely used at entries for parking garages and other checkpoints for vehicles. Customers buying barrier booms demand better performance of the systems in order to guarantee faster barrier movements despite of a very wide range of barrier lengths for different applications (from very short up to 8m or longer).

At the same time there is a desire from the market and from society to make the system more efficient in order to reduce the barrier motor size and the energy it requires. In order to reduce the motor power for lifting the rod nowadays the market offers two main solutions: either using counterweights in order to balance the weight of the rod during the rotation or using springs that give a contribution in the opposite direction than the one given by gravity and the rod weight.

The first solution uses counterweights on the opposite side of the rod in order to balance the weight of the rod during the movement. This solution is used mostly with the longest and heaviest rods but it is less and less used, replaced by the second solution with springs. In the second solution helical springs are used. They are pre-compressed during the installation in order to generate a torque opposed to the one given by the rod weight during the lifting of the rod from the horizontal condition.

Despite the use of counteracting solutions to reduce the load on the motor of the automatic boom barrier, the motor still need to be relatively large. This leads to large energy consumption and high costs for powerful and expensive motors. There is thus a need In the industry to develop automatic boom barriers with higher efficiency. Summary

The torque produced by a pre-compressed and counteracting spring, as described in the background section, does, however, not reduce identically with the reduction of gravity pull on a boom barrier that is lifted. This deviation has to be overcome by the motor of the automatic boom barrier. Figure 4 illustrates the deviation between the torque induced by a pre-compressed spring (the dashed line) and the torque induced by gravity on the boom barrier as a function of the boom angle. As can be seen the spring torque is lower than the boom torque when the boom is lowered down, to make sure that the boom remains closed without a need to lock it. When the boom is lifted the torque from the spring increases until the boom has been lifted about 15 degrees, then begins to decrease. As can be seen the spring torque deviates from the gravity induced torque from the boom constantly when opening the boom from 0 to 90 degrees, i.e. from a horizontal position of the boom to a vertical position of the boom.

The deviation between the counter-acting torque from the spring and the torque induced by gravity on the boom requires a motor operating the boom that can overcome the deviation. In practice a larger and more expensive motor has to be used due to the mentioned deviation leading to large energy consumption and high costs for manufacturing automatic barrier booms.

It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above mentioned problem. According to a first aspect there is provided a boom barrier for blocking vehicular or pedestrian access. The boom barrier comprises a boom fastened to and arranged to rotate around a horizontal shaft that is parallel to the direction of blockage of the barrier boom and an actuator for rotating the boom around the horizontal shaft. The boom barrier further comprises a counterweight spring in mechanical connection with the horizontal shaft to counteract the momentum induced by the weight of the boom, wherein the counterweight spring extends along a spring extension axis, and a compression plate, arranged to attach the counterweight spring to the boom. The boom barrier further comprises a spring compression adjustment unit arranged to attach the counterweight spring to the boom barrier for adjusting the compression of the counterweight spring. The spring adjustment unit comprises a control unit for controlling the compression of the counterweight spring based on the torque applied by the actuator on the horizontal shaft. An advantage with the disclosed boom barrier is that a real time adjustment of the counteracting weight to the weight of the boom is achieved when changing the counterweight spring characteristics in real time. In this way the engine effort required for moving the rod from 0° to 90° and backwards is significantly decreased without jeopardizing required speed performance. By controlling the compressions of the spring the torque required to move the boom can be uniform for the entire cycle of an opening or closing of the boom. The actuator for driving boom shaft can thereby be less powerful enabling the use of cheaper actuators requiring less energy for operating.

A further advantage of the disclosed adjustment of counterweight spring based on the torque of the actuator and not based is that if the surrounding conditions change, e.g. due to strong winds or extra weights applied to the boom, the spring can be adjusted to take that into account in real time.

A possible application of this concept is changing the spring characteristics. According to some embodiments, the counterweight spring is a spring comprised in the group consisting of: a coil spring, a gas spring, a flat spring, a machined spring, a serpentine spring, a garter spring, a cantilever spring, an arc spring, a volute spring, a hairspring, a leaf spring, and a V- spring, a magnetic spring.

According to some embodiments, the actuator is an electric motor. An advantage using an electrical motor is that it is strong per space and weight units an easy to control in a precise manner.

According to some embodiments, the control unit controls the compression of the counterweight spring based on the current consumption of the electric motor as equivalent to the torque applied on the horizontal shaft by the electric motor. This is a very precise and accurate method for estimating the torque of the electric motor.

According to some embodiments, the actuator is a hydraulic actuator, and the control unit controls the compression of the counterweight spring based on the pressure in a hydraulic liquid of the hydraulic actuator as equivalent to the torque applied on the horizontal shaft by the hydraulic actuator. A pressure measurement of the hydraulic liquid, e.g. oil, is a very precise and accurate method for estimating the torque of the actuator.

According to some embodiments, the spring compression adjustment unit comprises a first regulation plate arranged between the boom barrier and the counterweight spring, wherein the first regulation plate is adapted to move along the spring extension axis to thereby adjust the compression of the spring. By moving the first regulation plate the tension of the spring can be adjusted by direct compression and thereby the counterweight is also adjusted.

According to some embodiments, the spring compression adjustment unit comprises a second regulation plate arranged between the compression plate and the counterweight spring, wherein the second regulation plate is adapted to move along the spring extension axis to thereby adjust the compression of the spring. By moving the second regulation plate the tension of the spring can be adjusted by direct compression and thereby the counterweight is also adjusted.

According to some embodiments, the spring compression adjustment unit comprises a third regulation plate arranged between the compression plate and the counterweight spring, wherein the third regulation plate is adapted to move in a plane substantially perpendicular to the spring extension axis so as to adjust the momentum force inflicted by the counterweight spring on the boom. In this embodiment the spring compression unit does not change the spring compression per se, although the spring compression will be slightly affected as well, but instead changes the angle of the spring force on the attachment to the horizontal shaft. In that way the torque of inflicted by the spring can be adjusted in an equivalent way as if the spring compression is adjusted by changing the pre-compression.

According to some embodiments, the first regulation plate, the second regulation plate, or the third regulation plate are connected to the spring compression adjustment unit via a gear mechanism. Connecting the spring compression adjustment unit via a gear mechanism facilitates a robust and precise way of moving the first regulation plate, the second regulation plate, or the third regulation plate.

According to some embodiments, the mechanical connection between the counterweight spring and the horizontal shaft is achieved via a spring connection lever so that the counterweight spring inflicts a momentum force on the horizontal shaft equivalent to the rod length in the radial direction of the horizontal shaft.

According to some embodiments, the boom comprises a boom angle sensor, and wherein the control unit is electrical and adapted to control an electrical control motor, wherein the electrical control motor is arranged to move the first regulation plate, the second regulation plate, or the third regulation plate based on a signal from the boom angle sensor. The boom angle is directly coupled to the torque due to gravity on the boom and can be used to calibrate the spring adjustment unit to be optimized in view of the torque required by the actuator as every opening cycle will be more or less the same as long as the surrounding conditions are not changed.

According to some embodiments, the control unit is mechanical using cam profiles/ four bar mechanisms and a rod to move the first regulation plate, the second regulation plate, or the third regulation plate based on the cam profile and thereby in accordance with the angle of the boom. This is a mechanical way to adjust the spring compression in the same way for each use cycle. An advantage is that the solution does not require real time control. On the other side the solution has to be pre-calibrated to the spring and cannot take new conditions in boom weight or other changes in conditions into account.

According to a second aspect there is provided a method for operating a boom barrier according to the first aspect, the method comprising the steps of: receiving a request to open the boom; in response to receiving the request to open the boom, controlling the electric motor to rotate the horizontal shaft for opening the boom; adjusting the compression of the counterweight spring using the spring adjustment unit based on the current torque applied by the actuator on the horizontal shaft.

According to some embodiments, the boom barrier step of adjusting the compression further comprises moving the first regulation plate, the second regulation plate, or the third regulation plate to thereby alter the torque inflicted by the counterweight spring on the horizontal spring.

Effects and features of the second aspect are to a large extent analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the embodiments of the second aspect.

The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

Brief descriptions of the drawings

The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

Figure la shows a perspective view according to a first embodiment of the present disclosure.

Figure lb shows a perspective view according to the first embodiment of Figure la from another view angle.

Figure 2 shows a perspective view according to a second embodiment of the present disclosure.

Figure 3 shows a perspective view according to a third embodiment of the present disclosure.

Figure 4 shows a graph showing the torque as a function of the boom angle inflicted by the boom weight and the counterweight spring, respectively. Figure 5 shows a flow chart representing the method according to the present disclosure.

Detailed description

The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

Figure la and Figure lb show an embodiment of the first aspect of this disclosure of a boom barrier 1 for blocking vehicular or pedestrian access from two different view angles. The boom barrier comprises a boom 2 fastened to and arranged to rotate around a horizontal shaft H that is parallel to the direction of blockage of the barrier boom 1 and an actuator 3 for rotating the boom 2 around the horizontal shaft H. A counterweight spring 4 that is in mechanical connection with the horizontal shaft H is used to counteract the momentum induced by the weight of the boom 2. The four counterweight spring 4 extends along a spring extension axis E from a compression plate 6 where the counterweight spring 4 is attached to the boom 2. In the figures only one extension axis E is included but it is apparent from the Figure la and Figure lb that each counterweight spring 4 extends in the same direction. A spring compression adjustment unit 5 arranged to attach the counterweight spring 4 to the boom barrier 1 for adjusting the compression of the counterweight spring 4. The spring adjustment unit 5 comprises a control unit 10 for controlling the compression of the counterweight spring 4 based on the torque applied by the actuator 3 (not shown in Figure la and Figure lb) on the horizontal shaft H.

In the embodiment of Figure la and Figure lb the spring compression adjustment unit 5 comprises a first regulation plate 7 arranged between the boom barrier 1 and the counterweight spring 4. The first regulation plate 7 is adapted to move along the spring extension axis E to thereby adjust the compression of the spring.

The first regulation plate 7 is connected to the spring compression adjustment unit 5 via a gear mechanism 12. The mechanical connection between the counterweight spring 4 and the horizontal shaft H is achieved via a spring connection lever 18 so that the counterweight spring 4 inflicts a momentum force on the horizontal shaft H. The control unit 10 in Figure la is electrical and adapted to control an electrical control motor 13. The electrical control motor 13 is arranged to move the first regulation plate 7 based on a signal indicating the torque of the actuator (not shown).

The control unit 10 in the embodiment of Figure la and Figure lb will thus, based on the torque of the actuator (not shown) adjust the pre-compression of the counterweight springs 4 by moving the first regulation plate 7 so that the torque is basically the same as the torque inflicted by gravity on the boom 2 regardless of the angle of the boom. The movement is achieved by the gear mechanism 12 which is actuated by the electrical control motor 13.

The electrical control motor 13 is controlled by the control unit 10.

With reference to Figure 2 a second embodiment of the boom barrier 1 for blocking vehicular or pedestrian is disclosed. The boom barrier comprises a boom 2 fastened to and arranged to rotate around a horizontal shaft H that is parallel to the direction of blockage of the barrier boom 1 and an actuator 3 for rotating the boom 2 around the horizontal shaft H. A counterweight spring 4 that is in mechanical connection with the horizontal shaft H is used to counteract the momentum induced by the weight of the boom 2. The counterweight spring 4 extends along a spring extension axis E from a compression plate 6 where the counterweight spring 4 is attached to the boom 2. A spring compression adjustment unit 5 arranged to attach the counterweight spring 4 to the boom barrier 1 for adjusting the compression of the counterweight spring 4. The spring adjustment unit 5 comprises a control unit 10 for controlling the compression of the counterweight spring 4 based on the torque applied by the actuator 3 on the horizontal shaft H.

The spring compression adjustment unit 5 comprises a second regulation plate 8 arranged between the compression plate 6 and the counterweight spring 4, wherein the second regulation plate 8 is adapted to move along the spring extension axis E to thereby adjust the compression of the spring.

The control unit 10 in Figure 2 is electrical and adapted to control an electrical control motor 13. The electrical control motor 13 is arranged to move the second regulation plate 8 based on a signal indicating the torque of the actuator 3.

The control unit 10 in the embodiment of Figure la and Figure lb will thus, based on the torque of the actuator 3 adjust the pre-compression of the counterweight springs 4 by moving the second regulation plate 8 so that the torque is basically the same as the torque inflicted by gravity on the boom 2 regardless of the angle of the boom. The movement is achieved by the gear mechanism 12 which is actuated by the electrical control motor 13. The electrical control motor 13 is controlled by the control unit 10.

The mechanical connection between the counterweight spring 4 and the horizontal shaft H is achieved via a spring connection lever 18 so that the counterweight spring 4 inflicts a momentum force on the horizontal shaft H.

The boom barrier may further comprise a boom angle sensor 11, and wherein the control unit 10 is electrical and adapted to control an electrical control motor 13, wherein the electrical control motor 13 is arranged to move the second regulation plate 8 based on a signal from the boom angle sensor 11. The regulation of the second regulation plate 8 based on a signal from the boom angle sensor 11 has to be pre-calibrated in this embodiment.

With reference to Figure 3 a third embodiment of the boom barrier 1 for blocking vehicular or pedestrian is disclosed. The boom barrier comprises a boom 2 fastened to and arranged to rotate around a horizontal shaft H that is parallel to the direction of blockage of the barrier boom 1 and an actuator 3 for rotating the boom 2 around the horizontal shaft H. A counterweight spring 4 that is in mechanical connection with the horizontal shaft H is used to counteract the momentum induced by the weight of the boom 2. The counterweight spring 4 extends along a spring extension axis E from a compression plate 6 where the counterweight spring 4 is attached to the boom 2. A spring compression adjustment unit 5 arranged to attach the counterweight spring 4 to the boom barrier 1 for adjusting the compression of the counterweight spring 4. The spring adjustment unit 5 comprises a control unit 10 for controlling the compression of the counterweight spring 4 based on the torque applied by the actuator 3 on the horizontal shaft H.

The spring compression adjustment unit 5 comprises a third regulation plate 9 arranged between the compression plate 6 and the counterweight spring 4, wherein the third regulation plate 9 is adapted to move in a plane substantially perpendicular to the spring extension axis E so as to adjust the momentum force inflicted by the counterweight spring on the boom 2. The mechanical connection between the counterweight spring 4 and the horizontal shaft H is achieved via a spring connection lever 18 so that the counterweight spring 4 inflicts a momentum force on the horizontal shaft H. When the regulation plate 9 moves in the direction indicated by the arrow m, the angle of the spring extension axis E will rotate as indicated in Figure 3 thereby changing the angle that counterweight spring force is actuated onto the spring connection lever 18. The momentum force and thereby the torque inflicted on the horizontal axis H will thereby be increased (when the regulation spring moves in the direction m).

With reference to all of Figures la to Figure 3 the boom barrier may in some embodiments have a control unit that is mechanical (not shown) using cam profiles and a rod to move the first regulation plate 7, the second regulation plate 8, or the third regulation plate 9 based on the cam profile and thereby in accordance with the angle of the boom 2. A mechanical control may be useful in places where electricity is not available or not preferred for some reason.

Figure 4 discloses the principle behind the core of this disclosure. The torque produced by a pre-compressed and counteracting spring of prior art solutions , see the dashed line 14 in Figure 4, does not reduce identically with the reduction of gravity pull on a boom barrier that is lifted. Compare with the torque induced by gravity shown by the line 15. The deviation between the gravity torque and the counteracting torque from the spring has to be overcome by the motor of the automatic boom barrier. As can be seen the spring torque is lower than the boom torque when the boom is lowered down to its resting position at zero degrees to make sure that the boom remains closed without a need to lock it. When the boom is lifted the torque from the spring increases until the boom has been lifted about 15 degrees, it then begins to decrease. As can be seen the spring torque deviates from the gravity induced torque from the boom constantly when opening the boom from 0 to 90 degrees, i.e. from a horizontal position of the boom to a vertical position of the boom.

The deviation between the counter-acting torque from the spring and the torque induced by gravity on the boom requires a motor operating the boom that can overcome the deviation. The herein disclosed embodiments tries to minimize the deviation between the torque of the counterweight spring and the torque from the boom weight. As a result smaller motors can be used leading to smaller energy consumption and lower costs for manufacturing automatic barrier booms.

With reference to Figure 5, the second aspect of this disclosure is shown: a method for operating a boom barrier according to the first aspect. The method comprising receiving SI a request to open the boom 2; in response to receiving the request to open the boom 2, controlling S2 the electric motor 3 to rotate the horizontal shaft H for opening the boom 2; adjusting S3 the compression of the counterweight spring 4 using the spring adjustment unit 5 based on the current torque applied by the actuator 3 on the horizontal shaft H. The boom barrier step of adjusting the compression further comprises moving the first regulation plate 7, the second regulation plate 8, or the third regulation plate 9 to thereby alter the compression.

The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. For example, the skilled person realize that although compression springs are disclosed in the Figures, the invention may just as well realized using a tensions spring that is pre-tensioned to act as counter weight in the same way as the compression springs disclosed in the embodiments of Figures la, lb, 2 and 3. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.