US3568618A

US3568618A - Trim tab

Info

Publication number: US3568618A
Application number: US820240A
Authority: US
Inventors: William A Bedford Jr
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-04-29
Filing date: 1969-04-29
Publication date: 1971-03-09
Anticipated expiration: 1988-03-09

Abstract

A pair of spaced trim tabs are supported at the bottom of the transom of a boat to extend therebelow when the boat is at rest and when operating at a low speed. Each tab is pivotally supported by a bracket and is urged by a spring to a lowered position below the boat bottom limited to an angular position by a stop engagement between the tabs and the brackets.

Description

United'State s Patent [-ll] 3',5 68,618

72 Inventor William A. Bedford, Jr. [56] References Cited UNITED STATES PATENTS 95 2:2 1969 3,200,782 8/1965 Walden etal..... l l4/66.5

l t l Patented Mar. 9 1971 3,404,651 0/1968 Jensen e a] 14/66 5 [73] Assignee Graham P, Ols Primary Examiner-Andrew H. Farrell S t Fl Attorney-Harness, Dickey & Pierce ABSTRACT: A pair of spaced trim tabs are supported at the [54] F bottom of the transom of a boat to extend therebelow when 7 Chums the boat is at rest and when operating at a low speed. Each tab [52] [1.8. CI 114/665 is pivotally supported by a bracket and is urged by a spring to a B63b l/22 lowered position below the boat bottom limited to an angular Field of Search 114/655 position by a stop engagement between the tabs and the (P) brackets.

PATENTED MAR BIS?! 2,568, 18

sum 1 n; :11,:

INVE TOR.

PATENTED MAR 9197i 3,558 51 SHEET 2 OF 2 M/Z'dm a 297 215.);

ran/i ran BACKGROUND OF THE INVENTION Reference may be had to B. G. Vandre, US. Pat. No. 2,807,228 issued Sept. 24, 1957 for Adjustable Rear Flap For Boats over which the present invention patentably distinguishes.

SUMMARY OF THE INVENTION The invention pertains to the use of a pair of hinge tabs having a supporting bracket attachable to the transom of a boat near the bottom thereof to leave a space therebetween for an outboard motor when applied to a outboard motor driven boat. The tab is hinged to the bracket for pivotal movement relative thereto with a spring provided between the bracket and the tab which urges the tab downwardly to a predetermined angular position limited by a stop engagement between the tab and the bracket. The spring is so designed as to have the tab effective upon the initial driving of the boat to cause the rear end of the boat to move upwardly out of the water as the bow rises to maintain the boat in substantially horizontal position at all times. As the speed of the boat increases the tab will swing upwardly as the position of the boat is maintained by the planing of the rear end on the water.

In one form of the invention, the tabs may be further raised upwardly to have the spring lock the tab in raised position so that it may be backed or dragged over the ground without contact therewith. In one form of the invention, the bracket and tab are made from a casting and a U-shaped spring with a tapered end is engaged by an extending lip on the tab for producing a downward urge to the tab against a stop on the bracket with a predetermined force. When the tab is hinged upwardly by the increased speed of the boat the resistance to its movement is decreased due to the change of the contact point of the tab with the spring so that little resistance is offered to the movement of the boat by the tab.

In a second form of the invention, the bracket and tab are made from stampings which are hinged together with a coil spring on the connecting pintle having extending ends one of which engages the bracket the other of which engages the tab to urge it downwardly. A projecting lip on the tab engages the bracket when the tab is disposed in a desired angular position below the boat.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view of the rear end of a boat showing the transom thereof having a pair of spaced brackets secured near the bottom with hinged tabs which embody features of the present invention;

FIG. 2 is an enlarged broken view of the structure illustrated in FIG. 1, taken within the circle 2 thereof;

FIG. 3 is a sectional view of the structure illustrated in FIG. 2, taken on the line 3-3 thereof, with the tabs disposed in downward position;

FIG. 4 is a view of the structure illustrated in FIG. 3, with the tab shown in raised locked position;

FIG. 5 is a view of structure, similar to that illustrated in FIG. 3, showing another form of the invention with the tabs in downward angular position relative to the transom;

FIG. '5 is a view of the structure illustrated in FIG. 5, with the tab illustrated in raised position;

FIG. 7 is aview of the structure illustrated in FIG. 5, as viewed from the point 7 thereof; and

FIG. II is a broken sectional view of the structure illustrated in FIG. 7, taken on the line 3-3 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring specifically to FIGS. 1 to d inclusive, a boat 11 has a transom 12 at the rear end on which a pair of spaced tab structures 33 are supported near the bottom edge thereof. Each tab structure embodies a bracket I45 having

right angle flanges

15 and 16, the latter of which supports spaced sleeves 17 which functions as a hinge leaf. The sleeves 17 have a bottom extension 18 which forms a stop face 19. A tab 21 has a rectangular blade 22 and a pair of sleeves 23 which are simiiar to the sleeves 17 between which the sleeves 23 are hingedly supported on a hinge pin 24. A U-shaped spring 25 made of stainless steel, bronze, and other rust-resisting material, has a flange 26 containing a pair of apertures 27 which align with a pair of apertures 28 in the flange 15 of the bracket 14 and through which a pair of screws 29 extend for securing the spring to the central part of the bracket. The screws 29 support the bracket 14 which is further supported by a pair of screws 30 which extend through apertures provided near the ends thereof. An unsecured flange 31 of the U-shaped spring 25 forms the deflectable portion thereof and said edges 32 of the spring are tapered to change the spring rate of the flange 31. The tab 21 has a lip 33 disposed between the hinge sleeves 23 in position to engage the flange 31 of the spring 25. The pressure point of the lip 33 engages the maximum resistance point of the flange 31 and as the lip moves from the resistance point the resistance to hinging of the tab 21 reduces so that after the tab 21 starts to move, the resistance to movement progressively decreases. The frictional drag between the lip 33 and the flange 31 of the spring functions as a damper to prevent any undue vibration of the trim tabs in any of its positions. in FIG. 3, the tab 21 is shown in its down position into which it is urged by the U-shaped spring 25 with the forward edge of the tab abutted against the stop faces 19 of the sleeves 17 of the brackets 14. As the boat is propelled forwardly, the bow will move out of the water and the transom end will be raised by the tabs to maintain the boat in a substantially horizontal position at all times. As the speed increases the tabs will hinge upwardly to the rear maintaining the boat in parallel to its starting position as it planes over the water.

Another feature of the tab arrangement is that illustrated in FIG. 4 where the tabs are manually pulled upwardly into locked position with the end of the flange 31 of the spring extending over the lip 33 for maintaining the tab in raised position. This permits the boat to be slid backwardly, forwardly or sidewardly over the ground without any damage to the tab structure. The tabs provide the further feature of preventing the rear end of the boat from rapidly sinking when the throttle is reduced. The boat will not sink or drag down in the stern at reduced speed but will settle down in a level condition since the tabs will move downwardly to the position illustrated in FIG. 3 and provide lift for the stern so that the sinking thereof at the rear is avoided. The tabs produce the planing of the boat. with less effort and there is less violent reaction to rapid changes in the throttle and will plane at substantially less than what would be considered a normal planing speed. After this speed is reached there is no drag due to the presence of the tabs.

Similar structure is illustrated in FIGS. 5 to 3, wherein a tab structure 35 has a bracket 36 and a tab 37 formed as stampings. The bracket 36 is in the nature of a plate having hinged sleeves 33 at the ends between which hinge sleeves 39 on the tab 37 are secured by a hinge pin 41. The bracket 36 is secured in spaced relation to each other at the bottom of the transom 12 by a plurality of screws 42. The space between the sleeves 39 is occupied by a coil spring 43 secured over the hinge pin 41. One end of the spring 43 has an arm 45 which engages the bracket 36, the opposite end having an arm as which engages the tab 37 to urge it downwardly. At the central portion the tab 37, in the area of the spring 453, a flange 47 is bent downwardly which moves into stop engagement with the bracket 36 when disposed in downward angular relation to the transom 12. as illustrated in FIGS. 5 and S. In FIG. .6, the tab 37 is illustrated in raised position and an arcuate dotted line extension 47 on the outer end of the tab provides a tangential engagement with the water rather than an edge engagement therewith. The structure of FIGS. 5 to S functions in the same manner as that pointed out above with regards to the structure of FIGS. 1 to i with the exception that the structure of FIGS. 5

to 3 lacks the locking feature for the tab when the tab is manually urged to its maximum upwardly hinged position.

lclaim:

1. 'In a trim tab for a boat, a bracket securable to the lower bottom portion of the boat transom, a tab pivoted to said bracket, and metal spring means of U-shape having a fixed and a free leg, the free leg being located between the bracket and tab providing direct engagement with the tab for urging said tab downwardly and for resisting the upward pivotal movement of the tab with a predetermined force.

2. In a trim tab for a boat as recited in claim 1, wherein stop means are provided between the tab and bracket for limiting the downward hinging movement of the tab by said spring means.

3. In a trim tab for a boat as recited in claim 2, wherein the bracket has sleeves at the ends and wherein the tab has sleeve means and a projecting lip disposable between the bracket sleeves, said lip being engaged by the free leg of said spring means.

4. In a trim tab as recited in claim 3, wherein the spring means is made from a strip of spring steel with one leg supported on the bracket and the opposite leg extending rearwardly in spaced relation thereto in engagement with said lip.

5. In a trim tab as recited in claim 4, wherein the bottom edge of the rearwardly extending free leg engages the top of the lip for retaining the tab in maximum upward position when manually moved thereto.

6. In a trim tab as recited in claim 5, wherein the side edges of the U-shaped spring means taper toward each other to change the spring rate of the free leg.

7. In a trim tab as recited in claim 6, wherein a maximum resistance is provided between the free leg of the spring means and the lip when the tab engages the stop means which resistance reduces as the tab pivots upwardly.

Claims

1. In a trim tab for a boat, a bracket securable to the lower bottom portion of the boat transom, a tab pivoted to said bracket, and metal spring means of U-shape having a fixed and a free leg, the free leg being located between the bracket and tab providing direct engagement with the tab for urging said tab downwardly and for resisting the upward pivotal movement of the tab with a predetermined force.