GB2106383A

GB2106383A - Belt actuator for wave maker

Info

Publication number: GB2106383A
Application number: GB08128129A
Authority: GB
Inventors: Richard Charles Payne
Original assignee: SEASIM CONTROLS Ltd
Current assignee: SEASIM CONTROLS Ltd
Priority date: 1981-09-17
Filing date: 1981-09-17
Publication date: 1983-04-13
Also published as: GB2106383B

Abstract

The invention relates to the driving of the paddle of a wave maker to and fro in a body of liquid by use of an endless belt 12 secured to the displacer remote from the rocking axis 3, of the paddle and driven by a reversible motor. <IMAGE>

Description

SPECIFICATION Belt actuator The invention relates to means for driving wave makers having a liquid displacer adapted to be moved to and fro in a body of liquid to produce waves in the liquid.

According to the invention there is provided means for driving the liquid displacer of a wave maker to and fro in a body of liquid and comprising endless belt means having at least one reach generally in the direction of motion of the displacer, means for reversibly driving the belt means and means whereby the displacer is drivingly engaged by said reach of the belt means.

Where the displacer is pivotally mounted for rocking motion, the belt means is preferably attached to the displacer at an edge opposed to the pivot, and means may be provided whereby the said reach may be tilted to compensate for arcuate movement of the said edge of the displacer. The means whereby the displacer is attached to the belt means may be supported by guide means.

The belt driving means may comprise a servo motor and the belt means is preferably a timing belt.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings of which the single figure shows a wave making paddle arranged for rocking motion to and fro in a body of water.

The paddle 1 has a forward or active face 2 which is presented to the body of liquid 23 which may be for example in a tank. The paddle 1 is mounted on base 4 of a tank or the like by pivot 3 so that its to and fro motion is arcuate as shown by the arrows 5.

The paddle is driven by electro-mechanical linear oscillatory actuator 7 which comprises an endless timing belt 12 arranged about guide feels 13 and 1 6 whereby the belt forms two substantially horizontal reaches.

Guide wheel 1 6 is fixed to a shaft 1 7 which is mounted in a housing 8. Wheel 13 is mounted on shaft 14 which in turn is mounted in a housing 1 5 which is supported at a distance from housing 8 by means of bars 11 which also perform a guiding function to be described below.

A further wheel 1 8 is fast to the shaft 17 and this is driven by a belt or chain 1 9 from a drive wheel 20 fast to a shaft 21 also mounted in the housing 8 and driven by a reversible servo motor 22.

An upward projection 6 from the paddle 1 terminates in a collar 23 which is slidably mounted on the lower of the guide bars 11 and is drivingly engaged by the lower reach of the belt 12.

As the motor 22 rotates clockwise as shown in the figure, the lower reach of belt 12 moves to the left and the collar 23 moving with the belt, slides along the lower guide bar 11, moving the paddle forwardly, that is to say urging the active face 2 into the body of fluid 23 to initiate a wave therein.

The motor is arranged so that when the paddle has moved forwardly for a pre-determined distance, the motor reverses and the lower reach of the belt 12 moves to the right in the figure returning the paddle towards or even beyond the original position before the motor is again reversed and the paddle again executes a forward movement.

In order to compensate for the arcuate movement of the paddle, the collar 23 may in some embodiments be located in a vertical slot in the extension 6 of the paddle 1, but in the embodiment illustrated, the drive means 7 is pivotally mounted on a support 10 by pivot 9 in the housing 8 so that the portion of the belt 1 2 and lower guide bar 11 which is in contact with the collar 23 is at a constant distance from the pivot 3 of paddle 1.

Within limits imposed by the length of the guide bars 1 the stroke of the paddle can be varied at will. The control of the position of the paddle at any time may be arrived at by using a single turn servo mount potentiometer driven by spur gears on the opposite side of the drive pulley shaft 21.

The actuator offers a push-pull motion without incurring the need for the close manufacturing tolerances that are necessary for other push-pull devices such as ball screws or hydraulic cylinders.

Again, unlike such other devices for powering wave makers, no separate lubrication system need be used since the main drive element is a belt.

Other components such as bearings and slides may be of the sealed type or made of self lubricating material. Of primary importance is the fact that the dynamic mass of the actuator is smaller than that of the ball screw actuator, which is an important feature for the fast responding servo systems desirable in wave makers.

Developments in the apparatus may make it possible to dispense with the lower guide bar 11, in which case the geometry of the belt attachment may have to be carefully designed to ensure that no movements or out of plane forces are transmitted to the belt.

In another embodiment, not shown, an endless timing belt corresponding to belt 12 of the Fig. 1 embodiment operates submerged within a body of liquid as may be required for the operation of a piston-type displacer. A drive motor is mounted above the liquid and this drives the timing belt by means of drive means corresponding to belt 1 9 of the Fig. 1 embodiment, the drive means being a further endless timing belt or other suitable means.

1. A wave maker having at least one liquid displacer mounted for movement to and fro in a body of liquid and drive means for the displacer comprising endless belt means having at least one reach generally in the direction of movement of the displacer, means for reversibly driving the belt means and means whereby the displacer is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Belt actuator The invention relates to means for driving wave makers having a liquid displacer adapted to be moved to and fro in a body of liquid to produce waves in the liquid. According to the invention there is provided means for driving the liquid displacer of a wave maker to and fro in a body of liquid and comprising endless belt means having at least one reach generally in the direction of motion of the displacer, means for reversibly driving the belt means and means whereby the displacer is drivingly engaged by said reach of the belt means. Where the displacer is pivotally mounted for rocking motion, the belt means is preferably attached to the displacer at an edge opposed to the pivot, and means may be provided whereby the said reach may be tilted to compensate for arcuate movement of the said edge of the displacer. The means whereby the displacer is attached to the belt means may be supported by guide means. The belt driving means may comprise a servo motor and the belt means is preferably a timing belt. Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings of which the single figure shows a wave making paddle arranged for rocking motion to and fro in a body of water. The paddle 1 has a forward or active face 2 which is presented to the body of liquid 23 which may be for example in a tank. The paddle 1 is mounted on base 4 of a tank or the like by pivot 3 so that its to and fro motion is arcuate as shown by the arrows 5. The paddle is driven by electro-mechanical linear oscillatory actuator 7 which comprises an endless timing belt 12 arranged about guide feels 13 and 1 6 whereby the belt forms two substantially horizontal reaches. Guide wheel 1 6 is fixed to a shaft 1 7 which is mounted in a housing 8. Wheel 13 is mounted on shaft 14 which in turn is mounted in a housing 1 5 which is supported at a distance from housing 8 by means of bars 11 which also perform a guiding function to be described below. A further wheel 1 8 is fast to the shaft 17 and this is driven by a belt or chain 1 9 from a drive wheel 20 fast to a shaft 21 also mounted in the housing 8 and driven by a reversible servo motor 22. An upward projection 6 from the paddle 1 terminates in a collar 23 which is slidably mounted on the lower of the guide bars 11 and is drivingly engaged by the lower reach of the belt 12. As the motor 22 rotates clockwise as shown in the figure, the lower reach of belt 12 moves to the left and the collar 23 moving with the belt, slides along the lower guide bar 11, moving the paddle forwardly, that is to say urging the active face 2 into the body of fluid 23 to initiate a wave therein. The motor is arranged so that when the paddle has moved forwardly for a pre-determined distance, the motor reverses and the lower reach of the belt 12 moves to the right in the figure returning the paddle towards or even beyond the original position before the motor is again reversed and the paddle again executes a forward movement. In order to compensate for the arcuate movement of the paddle, the collar 23 may in some embodiments be located in a vertical slot in the extension 6 of the paddle 1, but in the embodiment illustrated, the drive means 7 is pivotally mounted on a support 10 by pivot 9 in the housing 8 so that the portion of the belt 1 2 and lower guide bar 11 which is in contact with the collar 23 is at a constant distance from the pivot 3 of paddle 1. Within limits imposed by the length of the guide bars 1 the stroke of the paddle can be varied at will. The control of the position of the paddle at any time may be arrived at by using a single turn servo mount potentiometer driven by spur gears on the opposite side of the drive pulley shaft 21. The actuator offers a push-pull motion without incurring the need for the close manufacturing tolerances that are necessary for other push-pull devices such as ball screws or hydraulic cylinders. Again, unlike such other devices for powering wave makers, no separate lubrication system need be used since the main drive element is a belt. Other components such as bearings and slides may be of the sealed type or made of self lubricating material. Of primary importance is the fact that the dynamic mass of the actuator is smaller than that of the ball screw actuator, which is an important feature for the fast responding servo systems desirable in wave makers. Developments in the apparatus may make it possible to dispense with the lower guide bar 11, in which case the geometry of the belt attachment may have to be carefully designed to ensure that no movements or out of plane forces are transmitted to the belt. In another embodiment, not shown, an endless timing belt corresponding to belt 12 of the Fig. 1 embodiment operates submerged within a body of liquid as may be required for the operation of a piston-type displacer. A drive motor is mounted above the liquid and this drives the timing belt by means of drive means corresponding to belt 1 9 of the Fig. 1 embodiment, the drive means being a further endless timing belt or other suitable means. CLAIMS

1. A wave maker having at least one liquid displacer mounted for movement to and fro in a body of liquid and drive means for the displacer comprising endless belt means having at least one reach generally in the direction of movement of the displacer, means for reversibly driving the belt means and means whereby the displacer is drivingly engaged by said reach of the belt means.

2. A wave maker according to Claim 1 wherein the displacer is pivotally mounted for rocking motion and the belt means is attached to the displacer at an edge opposed to the pivot.

3. A wave maker according to Claim 2 further comprising means whereby the said reach may be tilted to compensate for arcuate movement of the said edge of the displacer.

4. A wave maker according to any one of the preceding Claims wherein the means whereby the displacer is attached to the belt means is supported by guide means.

5. A wave maker according to any one of the preceding Claims wherein the belt driving means comprises a servo motor.

6. A wave maker according to any one of the preceding Claims wherein the belt means is a timing belt.

7. Means for driving the liquid displacer of a wave maker to and fro in a body of liquid and comprising endless belt means having at least one reach generally in the direction of motion of the displacer, means for reversibly driving the belt means and means whereby the displacer is drivingly engaged by said reach of the belt means.

8. A wave maker having at least one liquid displacer mounted for movement to and fro in a body of liquid substantially as described with reference to the drawings.

9. Means for driving the liquid displacer of a wave maker to and fro in a body of liquid substantially as described with reference to the drawings.