US-12620300-B2 - Shaft contact device

Abstract

The invention relates to a shaft contact device 1 to make an electrical connection between a shaft and an earth point. Device 1 has a bracket 10 for connection to a point spaced from the rotating shaft, base member 20 mounted on the bracket 10 , a head member 30 having at least one electrically conductive brush 34 A, 34 B to engage the shaft. A pair of arms 40 A, 40 B each has a first end connected to spaced pivot points on the base member and a second end connected to spaced pivot points on the head member. A spring means 50 biases the head towards the shaft to engage the brush on the shaft. In use the base member, head member and spaced arms forming a parallelogram arm whereby the head member brushes contact the shaft at a constant angle as the brushes are worn.

Inventors

• Wayne Cooper
• Edward Lau

Assignees

• Waynedd Enterprises Ltd

Dates

Publication Date

20260505

Application Date

20220131

Claims (20)

1. 1 . A shaft contact device to make an electrical connection between a rotating shaft and an earth point comprising: a bracket for connection to a point spaced from the rotating shaft; a base member mounted on the bracket; a head member having at least one electrically conductive brush to engage the rotating shaft; a pair of arms each having a first end connected to spaced pivot points on the base member and a second end connected to spaced pivot points on the head member, and a spring means to bias the head towards the rotating shaft to engage the at least one electrically conductive brush on the rotating shaft, in use the base member, head member and spaced arms forming a parallelogram arm whereby the at least one electrically conductive brush of the head member contacts the rotating shaft at a constant angle as the at least one electrically conductive brush is worn.
2. 2 . The shaft contact device according to claim 1 , wherein the bracket is adapted to be mounted on a connection point through which the rotating shaft extends.
3. 3 . The shaft contact device according to claim 1 , wherein the bracket is connected to a connection point using one or more cable ties.
4. 4 . The shaft contact device according to claim 3 , wherein slots are provided on the bracket to accommodate the one or more cable ties.
5. 5 . The shaft contact device according to claim 1 , wherein the bracket is of plastics and heat deformable to adjust its shape to lie adjacent different shapes at the spaced point to which it is to be attached.
6. 6 . The shaft contact device according to claim 1 , wherein the spring means spans opposing corners of a parallelogram defined by the arms and the spaced pivot points.
7. 7 . The shaft contact device according to claim 1 , wherein the arms have elongate recesses to accommodate the spring means when the arms come together adjacent each other.
8. 8 . The shaft contact device according to claim 1 , wherein the at least one electrically conductive brush are wired to a terminal to connect with a wire leading to an earth point anode or cathode.
9. 9 . The shaft contact device according to claim 1 , wherein the head includes an electrically conductive contact member adjacent the base member of the at least one electrically conductive brush which engages the rotating shaft when the brushes become worn.
10. 10 . The shaft contact device according to claim 9 , wherein an alarm circuit is provided to generate an alarm when the contact member engages the rotating shaft to indicate that the at least one electrically conductive brush needs replacing.
11. 11 . The shaft contact device according to claim 8 , wherein an alarm circuit is provided to operate an alarm if water is present between an electrically conductive contact member and the terminal to indicate that a seal around the rotating shaft is leaking.
12. 12 . The shaft contact device according to claim 1 , wherein the first and/or second ends of the arms are adapted to be connected to one of a number of spaced pivot points to adjust the constant angle of the head member relative to the base member.
13. 13 . A marine engine with a prop shaft or drive shaft, incorporating the shaft contact device according to claim 1 .
14. 14 . A system which includes the shaft contact device according to claim 8 and an alarm circuit which is operatively connected to a wireless transmitter which in use transmits an alert signal to a remote location upon receipt of a signal from a sensor.
15. 15 . The system according to claim 14 wherein the sensor detects that the at least one electrically conductive brush is worn.
16. 16 . The system according to claim 15 wherein a wireless receiver is configured to receive the alert signal and to display or relay a warning to indicate that the at least one electrically conductive brush is worn.
17. 17 . The system according to claim 15 wherein the sensor detects a variation in an electrical characteristic to indicate that the at least one electrically conductive brush is worn.
18. 18 . The system according to claim 15 wherein the sensor detects a variation in a mechanical characteristic to indicate that the at least one electrically conductive brush is worn.
19. 19 . The system according to claim 11 wherein a sensor detects if water is present between the electrically conductive contact member and the terminal or in a bilge to indicate if there is leakage between the rotating shaft and shaft seal.
20. 20 . A marine craft or vessel including the device according to claim 1 .

Description

FIELD The present invention relates to a shaft contact device and system. More particularly, but not exclusively, to a shaft with a contact means for use with a marine corrosion protection system. BACKGROUND It is common practice to use sacrificial anodes on boats to prevent metallic components from corroding due to electrolysis. Propeller drive shafts, propellers and gearboxes are connected electrically linked and damage to these by electrolysis can be very costly. PRIOR ART United States patent U.S. Pat. No. 5,052,962 (CLARK) discloses a corrosion reducer for use with ships having a propeller mounted on a propeller shaft which extending through the hull. The corrosion reducer includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft to reduce corrosion due to electrolytic action. United Kingdom patent application GB 1 462 931 (SKARPENORD) describes a cathodic protection for a ship's propeller which has a liner sleeve on the shaft and a layer of electrical insulation between the sleeve and shaft to insulate the shaft from the metal hull of the ship in which the shaft is installed. United Kingdom patent application GB 503 946 (LEPAGE) describes a device which prevents corrosion of condensers, propellers and other parts of ships in contact with sea water. A positive terminal of a continuous current generator is connected through variable resistances to iron anodes within, but insulated from, the condenser or similar components in the cooling circuit of an internal combustion engine. United States patent U.S. Pat. No. 3,049,479 (PREISER) discloses a method of electrically protecting a propeller against corrosion and cavitation in a sea water electrolyte by rendering the propeller as a cathode and locating the anode relative to the propeller such that a significant amount of electric current passes through the sea water electrolyte. United States patent U.S. Pat. No. 3,385,254 (Goldberg et al) discloses a system for boat electrolysis and a static electric eliminator which comprises a propeller shaft journaled therethrough. A current conducting brush has a portion of which contacts the shaft and a common electrical earth is provided in the boat. The invention seeks to provide a shaft contact device to connect a drive shaft, propeller and gearbox electrically to a sacrificial anode. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a shaft contact device to make an electrical connection between a shaft and an earth point comprising: a bracket for connection to a point spaced from the rotating shaft; a base member mounted on the bracket; a head member having at least one electrically conductive brush to engage the shaft; a pair of arms each having a first end connected to spaced pivot points on the base member and a second end connected to spaced pivot points on the head member, and a spring means to bias the head towards the shaft to engage the brush on the shaft, in use the base member, head member and spaced arms forming a parallelogram arm whereby the head member brushes contact the shaft at a constant angle as the brushes are worn. Preferably the bracket is adapted to be mounted on a seal through which the shaft extends. The bracket may be mounted on the seal using cable ties, screws, bolts or other attachments means. Slots may be provided on the bracket to accommodate the cable ties. Preferably the bracket comprises synthetic plastics portions and is heat deformable to enable its shape to be adjusted easily and so that it may rest or be placed against different parts of a boat or to adopt the shapes at a point to which it is to be attached. Preferably the spring means spans opposing corners of the parallelogram arm defined by arms and spaced pivot points. In some embodiments the arms have elongate recesses to accommodate the spring when the arms come together adjacent each other. Preferably the at least one brush is wired to a terminal to connect with a wire leading to an earth point, such as an anode. Optionally the brush may be wired to a current control means and/or a current sensing device. Preferably the head includes an electrically conductive contact member adjacent the base of the brush which engages the shaft when the brushes are worn. In some embodiments an alarm circuit is provided to generate and issue an alarm when the contact member engages the shaft to indicate that brush/es need replacing. According to a second aspect of the present invention there is provided a system which includes the shaft contact device and an alarm circuit connected to a wireless transmitter which is operative to transmit an alert signal to a remote location. Optionally the system includes a wireless receiver which is configured to receive the alert signal and to display or relay a warning to indicate when the brushes are worn. The brushes may include a portion of material which alters an electrical characteristic when