GB2085534A

GB2085534A - A marine frictional roller transmission unit with forward and reverse transmission

Info

Publication number: GB2085534A
Application number: GB8026745A
Authority: GB
Original assignee: HARP ROYALL ENGINEERING Ltd
Current assignee: HARP ROYALL ENGINEERING Ltd
Priority date: 1980-08-16
Filing date: 1980-08-16
Publication date: 1982-04-28
Also published as: GB2085534B

Abstract

A reversing gear for small boats comprises a drive member 2, a driven member 4, a reversing member 3 and an intermediate member 5, all of which are preferably rubber-tyred friction rollers and have parallel axes of rotation. The intermediate member 5 is carried by a pivotable lever 13 so that it always engages member 2 and can engage either of members 3 and 4 (which always engage one another) to drive the member 4 in reverse or forward direction. <IMAGE>

Description

.SPECIFICATION Marine frictional gearbox with reduction gear and reversing mechanism Our invention relates to a forward and reverse drive mechanism i.e. a mechanism for providing, as output rotation about an axis, the rotational sense of which can be selected at will, from a uni directional rotational input.

The precise manoeuvring of small self propelled boats and other small water borne craft is greatly assisted by the provision therein of a propulsion unit in which frequent rapid changes between forward and reverse drive, and neutral, are possible.

The use of known drive mechanisms for such applications is not entirely satisfactory because such mechanisms are expensive to provide in the first instance and, because of their complexity, are prone to mechanical breakdown in the conditions which generally prevail in and around small boats.

It is an object of this invention to provide a forward and reverse drive mechanism and neutral facility which is cheaper to produce than the known mechanisms used in small boats and which is less prone to mechanical breakdown.

In this invention there is provided a reversing mechanism comprising a drive member a reversing member and a driven member, all being rotatable about axes which are parallel each of which is at an apex of a notional triangle and an intermediate member which is movable along a path perpendicular to the said rotational axes between a disposition for forward drive in which it is in contact with the drive member and the driven member and not with the reversing member and a disposition for the reverse drive in which it is in contact with the drive member and the reversing member and not with the driven member; the intermediate member passing in said movement through dispositions in which it is in contact with the drive member only and not with either the reversing member or the driven member, thus assuring the neutral facility referred to.

Preferably the drive member, reversing member, driven member and intermediate member are rubber tyred rollers.

In such preferred embodiments it can be convenient for the driven member to be in constant contact with the reversing member.

Preferably the intermediate member rotates about a shaft carried on a lever which can pivot about an axis co-linear or co-incident with the axis of the drive member to provide the movement of the intermediate member between the dispositions for forward and reverse drive and neutral, In such preferred embodiment it is convenient for the intermediate member to be in constant contact with the drive member.

For a better understanding of the invention reference will now be made to the accompanying drawing which shows a view looking along the rotational axes of the members and a side elevation.

The drawing is to be regarded as diagrammatic in that no nuts, bolts or other fasteners are shown, neither are spacers within the framework shown.

This is for clarity.

In the drawing there is shown the drive member 2 the reversing member 3 the driven member 4 and the intermediate member 5. Each of these 4 members is a rubber tyred roller.

The drive member 2 is rotatable about an axis carried on an input shaft 6 in bearings 7 secured to the frame 1.

The reversing member 3 is rotatable about an axis carried on a shaft 8 in bearings 9 secured to the frame 1.

The driven member 4 is rotatable about an axis carried on an output shaft 10 in bearings 11 secured to the frame 1.

The intermediate member 5 is rotatable about an axis on a shaft 12 carried on a lever 13 which is arranged to pivot about the axis of the shaft 6 of the drive member 2.

The periphery of the driven member 4 is in constant contact with the periphery of the reversing member 3 so that when either of members 3 or 4 is caused to rotate the other will rotate at the same time but in the opposite directional sense. Adjustment will be provided so that members 3 and 4 will always remain in such constant contact.

The periphery of the intermediate member 5 is in constant contact with the periphery of the drive member 2, so that when the drive member 2 is caused to rotate the intermediate member 5 will rotate with it in the opposite directional sense.

Adjustment will be provided so that members 2 and 5 will always remain in such constant contact.

Pivoting of the lever 1 3 about the shaft 6 moves the intermediate member 5 between a disposition for forward drive in which its periphery is in contact with the driven member 4 (as shown in the drawing) and a disposition for reverse drive in which its periphery is in contact with the reversing member 3.

Between these two dispositions the periphery of the intermediate wheel 5 is in contact with the periphery of neither the reversing member 3 nor the driven member 4. In this mode there is no connection between the input shaft 6 and the output shaft 10 and thus the neutral or no drive disposition is achieved.

Used as a reversing mechanism an input drive is supplied to shaft 6 so that the drive member 2 and the intermediate member 5 are caused to rotate in opposite rotational sense. Lever 1 3 is moved into the disposition whereby the periphery of the intermediate member 5 is in contact with the periphery of the reversing member 3, causing them to rotate in opposite rotational sense. Thus it can be seen that reversing member 3 and drive member 2 rotate in the same rotational sense.

The periphery of reversing member 3 and the periphery of driven members 4 are in constant contact and so they always rotate in opposite rotational sense. Thus it can be seen that driven member 4 and drive member 2 rotate in opposite rotational sense. In this way reverse drive is achieved between the input shaft 6 and the output shaft 10.

When the lever is in the position shown in the drawing the shaft 10 is caused to rotate in the same rotational sense as the input shaft 6, and so a forward drive is provided at the output.

It will be readily apparent to the reader that output may be taken from the reversing member shaft 8, in which case the reversing member 3 becomes the driven member and the driven member 4 becomes the reversing member.

Also it will be readily apparent to the reader that input may be through shaft 8 and output through shaft 6 in which case wheel 3 is the drive member, wheel 4 is the reversing member wheel 2 is the driven member and wheel 5 remains the intermediate member.

Again, input may be through shaft 10 and output through shaft 6 in which case wheel 4 is the drive member, wheel 3 is the reversing member, wheel 2 is the driven member and wheel 5 remains the intermediate member.

The method of delivering drive to the input shaft 6 and the method of taking drive from the output shaft 10 are not shown. Normally the input would be from an engine or other prime mover and the output to a propeller shaft, possibly in both cases through a system of vee velts and pulleys.

The drawing does not show the manner in which the lever 13 may be moved between the forward neutral and reverse drive positions. There are a number of methods by which this might be achieved and they are external to the invention itself.

Speed reduction between input and output shafts may be achieved by altering the diameters of the drive and driven rubber rollers with respect to one another. This facility will be particularly useful when an output of a different rotational speed from the input is required.

Claims

1. A forward and reverse driving mechanism with a facility to disengage the drive i.e. put into neutral, comprising a drive member, a reversing member and a driven member, all members rotatable about axis which are parallel and whose centres are each at the apex of a notional triangle; and an intermediate member which is movable along a path perpendicular to the said rotational axes between a disposition for forward drive in which it is in contact with the drive member and the driven member and not with the reversing member and a disposition for reverse drive in which it is in contact with the drive member and the reversing member and not the driven member, the intermediate member passing in said movement through dispositions in which it is in contact with the drive member alone and not with the reversing member or the driven member.

2. A forward and reverse driving mechanism frictional transmission unit as herein before described and with reference to the accompanying drawings and as claimed in any preceding claim.

2. A forward and reverse driving mechanism substantially as hereinbefore described with the rotational speed of the output shaft connected to the driven member different from the rotational speed of the input shaft connected to the drive member in a pre-designed ratio.

This is achieved by varying the diameters of the drive member and driven member and gives rise to the desirable speed reduction facility of this invention.

New claims or amendments to claims filed on 14 January 1982.

Superseded claims 1 and 2.

New or amended claims:-

1. A marine frictional roller transmission [Gear Box] with forward and reverse mechanism.