Title:
STABILIZER TRIM ATTACHMENT FOR POWER BOATS
United States Patent 3577948
Abstract:
An attachment for a power boat which fits on the transom or stern of the boat and comprises a pair of trim tabs hinged at the transom and extending rearwardly therefrom, and which may be swung vertically simultaneously to different angular positions to trim the boat so that it operates at the proper attitude regardless of its loading. The tabs are so formed that they also bring about lateral stability as well as impart the proper attitude to the boat. Furthermore, the tabs are positively moved vertically up or down to their selected angular positions.
US Patent References:
Seaplane
Parker - May 1944 - 2347841
Trim attachment for power boats
Bennett - September 1968 - 3399643
Boat-trimming vane mechanism
Jensen et al. - October 1968 - 3404651
BOAT LEVELER MECHANISM PISTON CONSTRUCTION
Kercheval - September 1969 - 3468278
Seaplane
Parker - May 1944 - 2347841
Trim attachment for power boats
Bennett - September 1968 - 3399643
Boat-trimming vane mechanism
Jensen et al. - October 1968 - 3404651
BOAT LEVELER MECHANISM PISTON CONSTRUCTION
Kercheval - September 1969 - 3468278
Application Number:
04/815404
Publication Date:
05/11/1971
Filing Date:
04/11/1969
View Patent Images:
Export Citation:
Assignee:
Star Tab, Inc. (Logan, OH)
Primary Class:
International Classes:
B63B39/06; B63B39/00; B63B1/22
Field of Search:
114/66.5 (P)/
Primary Examiner:
Farrell, Andrew H.
Claims:
I claim
1. In combination with a power boat having a bottom and a transom connected together at a joint at the stern of the boat; a pair of trim-tabs hinged to the boat adjacent said joint and on opposite sides of the centerline thereof;
1. In combination with a power boat having a bottom and a transom connected together at a joint at the stern of the boat; a pair of trim-tabs hinged to the boat adjacent said joint and on opposite sides of the centerline thereof;
Description:
BACKGROUND OF THE INVENTION
Various trim tab attachments have been provided in the past for obtaining the proper attitude in the movement of the boats through the water under various loaded conditions. However, these prior art attachments have not included means for obtaining lateral stability. Also, the operating means for these tabs have not been positive in both directions to permit a definite selection of angular position of the tabs. According to the present invention, lateral stability is accomplished as well as positive selection of the angular position of the tabs in order to obtain the desired attitude of the boat under various loaded conditions.
In the accompanying drawings, I have illustrated a preferred embodiment of my invention and in these drawings:
FIG. 1 is a side elevational view of a portion of a boat at its stern, partly broken away, showing my attachment applied to the transom thereof.
FIG. 2 is a horizontal sectional view taken along line 2-2 of FIG. 1.
FIG. 3 is a rear view taken along line 3-3 of FIG. 1.
FIG. 4 is a schematic diagram of the hydraulic and electric control circuit for controlling the angular position of the trim tabs.
With reference to the drawings, I have shown in FIG. 1, the stern portion of a power boat of the inboard motor type with the transom 10 and the bottom 11 converging at a lower corner 12. The trim tabs of this invention are indicated generally at 13 and 14 and are hinged about a transverse axis, indicated at 15, for vertical swinging movement. This axis is adjacent the corner 12.
The tabs 13 and 14 are hinged side by side, but with a space 16 therebetween. If the attachment is used on an outboard motor type boat this spacing could be increased if necessary. Each tab is made of relatively stiff sheet metal with a straight forward edge which is hinged to the transom 10, preferably by a piano-type hinge 17. The rear edge of the tab is turned upwardly at a transverse joint 18 parallel with the front or leading edge of the tab so as to provide an upwardly and rearwardly projecting angular extension which stiffens the tab and provides for smoother flow of water over its rear edge. It will be apparent that due to the location of the hinge 17, the main body of the tab is, in effect, an extension of the bottom of the boat being coplanar therewith. The extension 19 extends upwardly and rearwardly from the tab so as to reduce turbulence at the rear edge of the tab. It will be noted that the corners of the extension 19 are angled at 20 to further reduce turbulence.
To obtain lateral stability as the boat is passing through the water, each tab at each edge is provided with a depending stabilizing flange 21 which also reinforces the body of the tab to make it rigid. It will be noted that each flange 21 angles downwardly from the hinge 17, where its edge is substantially flush with the bottom 11, to its rear end 22, at the joint 18, where it depends from the body of the tab a substantial distance. Each depending flange 21 is in a vertical plane at a right angle to the flat plane of the body of the trim tab.
Each of the tabs 13 and 14 is moved up or down positively to a selected angular position by means of a double-acting hydraulic ram or cylinder and piston unit 25. This unit 25 is pivotally connected to the transom 10 at 23, on its outer vertical surface, and to the tab at 24, on its upper surface rearwardly of the hinge axis 15 and adjacent the joint 18. The units 25 are preferably simultaneously activated by means of a combined motor and pump unit 26, located within the boat, preferably mounted on the inner surface of the transom, being connected to the units 25 by the necessary flexible conduit 27.
As the boat passes through the water, the proper attitude may be obtained by operating the switch 30 to select the proper angle on the two tabs 13 and 14 simultaneously. The switch 30 will be of the double-throw, double-pole type and will normally be held spring biased into "off" position. It will control a reversible motor 26a of the unit 26 which will, in turn, control the reversible hydraulic pump 26b of that unit. Driving the motor 26a in one direction will actuate the rams 25 to swing the tabs 13 and 14 upwardly simultaneously and driving the motor in the other direction will actuate the rams 25 to swing them downwardly. As the boat is powered through the water, the water will pass beneath the flat bodies of the tabs 13 and 14, which will provide planing surfaces, and then over the rearwardly and upwardly angled extensions 19 with a minimum of turbulence. The flanges 21 projecting downwardly into the water will create lateral stability. This is especially true at the center where water is passing through the space 16, between the two tabs, which space is lined up with the keel or centerline of the boat and acts on both adjacent flanges 21 to obtain a high degree of lateral stabilization. Positive displacement of the tabs up or down, as described, may be obtained merely by moving the activating lever of the switch 30 in the proper direction. By using two separate tabs they can be spaced apart as desired and angularly related relatively depending upon the transverse contour of the bottom of the boat and the transom.
Various trim tab attachments have been provided in the past for obtaining the proper attitude in the movement of the boats through the water under various loaded conditions. However, these prior art attachments have not included means for obtaining lateral stability. Also, the operating means for these tabs have not been positive in both directions to permit a definite selection of angular position of the tabs. According to the present invention, lateral stability is accomplished as well as positive selection of the angular position of the tabs in order to obtain the desired attitude of the boat under various loaded conditions.
In the accompanying drawings, I have illustrated a preferred embodiment of my invention and in these drawings:
FIG. 1 is a side elevational view of a portion of a boat at its stern, partly broken away, showing my attachment applied to the transom thereof.
FIG. 2 is a horizontal sectional view taken along line 2-2 of FIG. 1.
FIG. 3 is a rear view taken along line 3-3 of FIG. 1.
FIG. 4 is a schematic diagram of the hydraulic and electric control circuit for controlling the angular position of the trim tabs.
With reference to the drawings, I have shown in FIG. 1, the stern portion of a power boat of the inboard motor type with the transom 10 and the bottom 11 converging at a lower corner 12. The trim tabs of this invention are indicated generally at 13 and 14 and are hinged about a transverse axis, indicated at 15, for vertical swinging movement. This axis is adjacent the corner 12.
The tabs 13 and 14 are hinged side by side, but with a space 16 therebetween. If the attachment is used on an outboard motor type boat this spacing could be increased if necessary. Each tab is made of relatively stiff sheet metal with a straight forward edge which is hinged to the transom 10, preferably by a piano-type hinge 17. The rear edge of the tab is turned upwardly at a transverse joint 18 parallel with the front or leading edge of the tab so as to provide an upwardly and rearwardly projecting angular extension which stiffens the tab and provides for smoother flow of water over its rear edge. It will be apparent that due to the location of the hinge 17, the main body of the tab is, in effect, an extension of the bottom of the boat being coplanar therewith. The extension 19 extends upwardly and rearwardly from the tab so as to reduce turbulence at the rear edge of the tab. It will be noted that the corners of the extension 19 are angled at 20 to further reduce turbulence.
To obtain lateral stability as the boat is passing through the water, each tab at each edge is provided with a depending stabilizing flange 21 which also reinforces the body of the tab to make it rigid. It will be noted that each flange 21 angles downwardly from the hinge 17, where its edge is substantially flush with the bottom 11, to its rear end 22, at the joint 18, where it depends from the body of the tab a substantial distance. Each depending flange 21 is in a vertical plane at a right angle to the flat plane of the body of the trim tab.
Each of the tabs 13 and 14 is moved up or down positively to a selected angular position by means of a double-acting hydraulic ram or cylinder and piston unit 25. This unit 25 is pivotally connected to the transom 10 at 23, on its outer vertical surface, and to the tab at 24, on its upper surface rearwardly of the hinge axis 15 and adjacent the joint 18. The units 25 are preferably simultaneously activated by means of a combined motor and pump unit 26, located within the boat, preferably mounted on the inner surface of the transom, being connected to the units 25 by the necessary flexible conduit 27.
As the boat passes through the water, the proper attitude may be obtained by operating the switch 30 to select the proper angle on the two tabs 13 and 14 simultaneously. The switch 30 will be of the double-throw, double-pole type and will normally be held spring biased into "off" position. It will control a reversible motor 26a of the unit 26 which will, in turn, control the reversible hydraulic pump 26b of that unit. Driving the motor 26a in one direction will actuate the rams 25 to swing the tabs 13 and 14 upwardly simultaneously and driving the motor in the other direction will actuate the rams 25 to swing them downwardly. As the boat is powered through the water, the water will pass beneath the flat bodies of the tabs 13 and 14, which will provide planing surfaces, and then over the rearwardly and upwardly angled extensions 19 with a minimum of turbulence. The flanges 21 projecting downwardly into the water will create lateral stability. This is especially true at the center where water is passing through the space 16, between the two tabs, which space is lined up with the keel or centerline of the boat and acts on both adjacent flanges 21 to obtain a high degree of lateral stabilization. Positive displacement of the tabs up or down, as described, may be obtained merely by moving the activating lever of the switch 30 in the proper direction. By using two separate tabs they can be spaced apart as desired and angularly related relatively depending upon the transverse contour of the bottom of the boat and the transom.