Machine element or mechanism – Gearing – Alternating rotary
Patent
1995-06-22
1998-01-20
Wright, Dirk
Machine element or mechanism
Gearing
Alternating rotary
192 98, B63H 2308, F16H 6330, F16D 2104
Patent
active
057091285
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a transmission, e.g. a reversing gear for boats, comprising a shaft, a pair of gears provided with friction elements and freely rotatably mounted on said shaft, an engaging sleeve with frictional surfaces and displaceable on said shaft, said frictional surfaces being disposed to cooperate with the frictional elements of the gears to lock one of the gears to the shaft, and a dog which extends radially into a V-groove disposed excentrically in relation to the rotational axis of the engaging sleeve, and is joined to a pin housed in a box in a rotational sleeve element, said bore running excentrically relative to the axis of rotation of the sleeve element so that rotation of the sleeve element results in displacement of the dog in the longitudinal direction of the shaft.
BACKGROUND OF THE INVENTION
A reversing gear for boats of the above mentioned type, which is known for example by SE-A-194 544, has the basic feature that the engaging sleeve and the shaft have cooperating threads, which amplify the engaging forces. For shifting, a relatively high disengaging force is required, and this is difficult to achieve without some form of servo assistance. One method is to extract servo force via the input torque to the transmission by means of a dog and an engaging sleeve with an excentric groove as described in the above mentioned publication. Upon relative rotation between the dog and the excentric groove, a knocking effect is achieved when the dog is moved axially to move the engaging sleeve in a disengaging direction, and thus a low manual disengaging force is sufficient.
Since the axial displacement of the dog is achieved by rotating a sleeve element in which a pin solidly joined to the dog is journalled, the dog will move when axially displaced along a circular arc at the same time, which will mean that it also moves tangentially. This means that the dog, which has a curvature corresponding to the curvature of the V-shaped groove, can in principle only have one position with perfect surface contact with the groove. In the known embodiment, this position is the neutral position of the reversing gear. Upon tangential movement during the shifting movement, the contact surface will be reduced between the dog and the groove. Thus, this design places great demands on the strength of materials and machining accuracy.
SUMMARY OF THE INVENTION
The purpose of the present invention is to provide a transmission of the type described by way of introduction, in which it is possible to maintain the same good surface contact between the dog and the groove in the shift positions as in the neutral position.
This is achieved according to the invention by virtue of the fact that the dog is connected to the pin via an articulated joint which permits pivoting of the dog relative to the pin around at least one pivot axis, which is parallel to the rotational axis of the engaging sleeve.
With the aid of the articulated joint, the dog can automatically adapt itself so that it will always lie correctly in the groove in the engaging sleeve. This provides better shifting properties, less wear on the components and longer useful life.
In a preferred embodiment of the transmission according to the invention, the articulated joint is a ball-and-socket joint in connection with a central portion of a dog which extends over approximately a semi-circle. Said central portion and portions at each end of the semi-circle extend deeper into the V-shaped groove than the portions therebetween. The actual displacement of the engaging sleeve is achieved primarily by means of the central portion, which can have a peripheral extent corresponding to that of the known dog. The end portions are primarily intended to reduce tendencies of the dog to tip, which would otherwise be the case when, for reasons of space, it is necessary to use a ball-and-socket joint, the pivot center of which lies outside the dog surfaces in contact with the V-shaped groove.
BRIEF DESCRIPTION OF THE DRAWINGS
The invent
REFERENCES:
patent: 774837 (1904-11-01), Eshelman
patent: 1149283 (1915-08-01), Pfeiffer
patent: 1418429 (1922-06-01), Carpenter
patent: 3788157 (1974-01-01), Carlson et al.
patent: 4630719 (1986-12-01), McCormick
AB Volvo Penta
Wright Dirk
LandOfFree
Reversing gear for boats does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reversing gear for boats, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reversing gear for boats will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-718737