Abstract of
GB951038
951,038. Reverse gear and control; friction clutches. VOLVO-PENTA A.B. Nov. 22, 1962 [Nov. 24, 1961 ; Sept. 10, 1962], No. 44272/62. Headings F2C and F2D. In a forward-neutral-reverse gear for a marine outboard motor, forward or reverse opposed bevel gears 1, 2 freely carried by an output shaft 3 and meshing a driving bevel pinion fast with an input shaft, are selectively clutched to the shaft 3 by a double-ended slidable friction cone clutch member 7 helically splined on the shaft 3 to provide a self-tightening action on clutch engagement. The clutch member 7 is normally engaged by a spring with the forward drive bevel 1 and controlled by two electromagnetic devices 12, 14 which when energized, respectively serve to disengage the clutch member 7 and engage it, against the spring bias, with the reverse bevel 2, the member 7 being formed with a central groove 9 provided each side with inclined cam surfaces 11. On energization of the magnet 12, a pin 13 moves radially inwards to engage one of the cam surfaces 11 whereby the member 7 is moved to a central neutral position and locked there by further penetration of the pin 13 into the groove 9. Reverse is engaged by energizing the magnet 14, or operating a manual lever 16, to turn an eccentric pin 15 permanently engaging the groove 9, which moves the clutch member 7 into engagement with the reverse bevel 2, the pin 13 being withdrawn when the pin 15 starts to rotate, the control devices 12, 14 being electrically interconnected to prevent the pin 13 locking the member 7. The spring 8 may be omitted in which case the clutch member 7 by its own weight engages the bevel 2 for forward drive, reverse then being effected through the bevel 1, the input shaft being driven in the opposite direction to the former arrangement or, a reversible pitch propeller is used. In Fig. 4 the clutch member is controlled solely by an eccentric pin such as 15, Fig. 1, the rock shaft 31 of which is turned by manually rocking a shaft 34 having an eccentric 35 engaging a V- groove in the shaft 31 through a spring loaded ball 40 which serves to resiliently maintain the shift device in either extreme engaged position whilst the manual rock shaft can be further rotated to perform additional functions such as to increase the engine fuel supply. In Fig. 6, the shaft 41 carrying the eccentrically mounted clutch shift pin is rotated by a forked arm 42 operated by a control lever 43 through a link 44 spring loaded against the bottom of the forked arm such that, as before, on further rotation of the operating lever beyond that required for clutch engagement, the rod rides up the slot of the lever against the spring bias.
1. A reversing gear for a drive shaft, such as a propeller shaft of a boat, comprising an input shaft with a bevel pinion in mesh with two bevel gear wheels freely rotatable on an output shaft and facing in opposite directions, and an intermediate clutch element which is axially displaceable on the output shaft for alternative engagement with two clutch members firmly connected each to its gear wheel, characterized in that the clutch element is turnable and axially movable within limits along helical splines on the output shaft and that the clutch parts consist of externally and internally conical membrs, respectively, having co-operating friction surfaces.
2. A reversing gear according to claim 1, characterized in that the clutch element is positively movable toward a normal position in which it engages one of the clutch members, that an electro-magnetically adjustable disengaging device is provided for displacing the clutch element out of engagement with either clutch-member to an intermediate neutral position, and that an electromagnetically controllable operating device is provided for displacing the clutch element into engagement with the other clutch member.
3. A reversing gear according to claim 1 or 2, characterized in that the clutch element has a central radial groove for co-operation with a radial pin connected to the disengaging device and/or operating device.
4. A reversing gear according to claim 3, characterized by short projections each on one side of the groove, said projections having wedge-shap-d lateral surfaces which gradually merge into the walls of the groove.
5. A reversing gear according to claim 2, characterized in that the disengaging device compr.ises a pin which is radially movable toward the clutch element and during this movement strikes against the projections and pulls the element out of engagement by contacting said lateral surface.
6. A reversing gear according to any of the preceding claims, characterized in that the operating device comprises an eccentric pin ext-,nding radially toward the clutch element, said pin being permanently in engagement with the groove and revolvable for displacement of the clutch element in either direction.
7. A reversing gear according to claim 1 or 2, characterized in that the clutch element 60 is movable toward the normal position by means of a helical spring or similar member.
8. A reversing gear according to claim 1 or 2, characterized in that the clutch element is movable toward the normal position by its 65 own weight.
9. A reversing gear according to claim 1, characterized in that it comprises a lever controlled operating device and a shift device acting upon the clutch element, said 70 devices being rigidly interconnected in an intermediate position and resiliently interconnected upon displacement from said intermediate position.
10. A reversing gear according to claim 75 9, characterized in that each of the operating devic, and the shift device comprises a turnable shaft, said shafts being parallel to each other and inter-connected for common turning in opposite directions by means of an 80 eccentric disc connected to one of the shafts and adapted to engage a V-shaped groove in the other shaft such that the eccentric disc in the above named intermediate position without play abuts upon both lateral surfaces of 85 the V-shaped groove and upon turning from said intermediate position engages one or the other of the lateral surface s of the groove by means of an elastic device provided in the eccentric disc. 90 11. A reversing gear according to claim 10, characterized in that the elastic device comprises a ball biased by a spring which in the intermediate position of the operating device and shift device acts in the direction 95 toward the bottom of the V-shaped groove.
12. A reversing gear according to claim 9, characterized in that the shift device comprises a shaft adapted to be turned by means of a bifurcated lever and that the operating 100 device comprises a link which at one end is articulated to the control lever and adapted in the above named intermediate position to be spring-biased to engagement with the bottom of the bifurcated lever and upon displacement from the intermediate position to slide along one of the prongs of the bifurcated lever so as still more to stretch the spring.
13. A reversing gear for a drive shaft, 110 substantially as described with reference to Fig. I or Figs 2-5 or Fig. 6 of the accompanying drawings.
Sheerness: Printed for Her Majesty's Stationery Office, by Smiths Printers and Duplicators.-1964.
Published at the Patent Office. 25 Southampton Buildings, London, W.C.2., from which copies may be obtained.
Description
PATENT SPECIFICATION
DRAWINGS ATTACHED Date of Application and filing Complete Specification
November 22, 1962.
No. 44272/62.
Application made in Sweden (No. 11722) on November 24, 1961.
Application made in Sweden (No. 9779) on September 10, 1962.
Complete Specification Published March 4, 1964.
Crown Copyright, 1964.
951,038 Index at Acceptance: Classes F2, D(6C7:13C7A:13D2A1:13E1C:13K2); F2, C(1C4A:1C7:1C9:1E7).
Ir:ernational Classification: F 06 h. (F 06 d).
Improvements in or relating to reversing gears.
COMPLETE SPECIFICATION
We, AKTIEBOLAGBT VOLVO-PENTA, of Hjalmar Brantingsplatsen, Gothenburg, Sweden, a Swedish Body Corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and th- method by which it is to be performed, to be particularly described in and by the following statement:
This invention relates to a reversing gear for a drive shaft, such as a propeller shaft of a boat, comprising an input shaft with a bevel pinion in mesh with two bevel gear wh els freely rotatable on an output shaft and facing in opposite directions and consequently rotating in opposite directions. Between these gear wheels there is provided a clutch element which is axially displaceable on the output shaft for alternative engagement with two clutch members firmly connetted each to its gear wheel. Consequently, the direction of rotation of the output shaft depends upon which of the clutch members is in engagement with the clutch element.
The operating force required for the displacement of the clutch element is comparatively small and can be exerted by means of a hand lever or by means of electromagnetic members, whereas the required holding power of the clutch between the clutch parts for transmitting the driving torque is comparatively great. The main object of the invention is to provide a reversing gear of smple construction which is easy to operate without shocks and in addition keeps the clutch parts in firm engagement. The invention is characterized by the fact that the clutch element is turnable and axially movable within limits along helical splines on the output shaft and that the clutch parts consist of externally and internally conical members, respectively, having co-operating friction surfaces.
Various specific embodiments of the invention will now be described more closely by way of example with reference to the accom(Pr, panying drawings in which: Fig. 1 is a longitudinal sectional view of a reversing gear for a motor boat engine comprising electromagnetic operating means, Fig. 2 is a corresponding sectional view of a manually 50 operated gear, Fig. 3.is a cross-sectional view along the line II-II in Fig. 2, Fig. 4 a partial sectional view along the line III-III in Fig. 3, Fig. 5 a sectional view corresponding to Figure 4 and showing the parts in 55 other positions, and Figure 6 a diagrammatic lateral view of a further embodiment.
Referring to Figure 1 a shaft driven by an engine is provided with a bevel pinion in permanent mesh with two bevel gear wheels 60 1 and 2 which are freely rotatably mounted on a shaft 3 adapted to drive the propeller shaft of a boat. The gear wheels 1, 2 are facing each other resulting in that the shaft 3 will be. driven in opposite directions 65 depending upon its engagement with either of the gear wheels. The gear wheels 1, 2, are axially and radially mounted in a case 4 and their end surfaces facing each other are provided with fixed clutch members 5 and 70 6, respectively, having conical friction surfaces. Between the clutch members 5, 6 a clutch element 7 having two conical friction surfaces is axially movable on helical splines on, the shaft 3, such that the clutch 75 element upon contact with one of the clutch members will be screwed into self-tightening clutch-engaging contact with the said clutch member under the action of the frictional torque. In the normal position of the clutch 80 which in this embodiment corresponds t, the position for ahead propulsion of the boat one of the friction surfaces of the clutch element is in engagement with the friction surface of the clutch member 5 under the 85 action of a helical spring 8.
Reversing of the clutch and shifting to disengaged position is accomplished by means of electromagnetically operated devices. To this end, the clutch element 7 has a central 90 951,038 radial deep groove 9 and short projections 10 one on each side of the groove. The lateral surfaces 11 of the projections are wedgeshaped converging toward the groove 9 such as to merge into the groove 9 at the opposite side of the element.
A disengaging device 12 is radially inserted in the case 4 in opposed relation to the neutral position of the groove 9 and comprises an electromagnet adapted to move a pin 13 radially into the groove 9.
The diameter of the pin is substantially equal to the width of the groove 9 and the pin is retained in this position as long as the current is switched on and is withdrawn by a spring in the device 12 when the current is switched off. Instead, the electromagnet may be double-acting such as to cause insertion as well as withdrawal of the pin.
When the element 7 is in engagement with either of the clutch members S or 6, and the engine is running a considerable force is required to throw the clutch out of gear. In this operating condition the pin 13 is retracted in the device 12 and the central line of the groove 9 is offset from the axis of the pin 13. When the current to the electromagnet is switched on the nin 13 will be expelled toward the element 7 and strike against one of the projections 10. Upon continued rotation of the element the pin 13 travels along the lateral surface 11 of the projection 10 and pulls the element 7 out of engagement with the clutch member. After half a revolution the element 7 has been displaced so far that the pin 13 can snap into the groove 9 whereupon the element 7 is out of engagement with both clutch members 5 and 6 resulting in that the shaft 3 will not be driven any longer.
For reversing the direction of rotation of the shaft 3, from ahead operation to astern operation it is first necessary to throw the clutch out of gear as described above. In order to engage the element 7 with the clutch member 6 it has to be forced down against the action of the spring 8. This is accomplished by means of a reversing device 14 which is radially inserted into the case opposite to the device 12, said reversing device comprising an electromagnet adapted to turn an eccentric pin 15 inserted in the groove 9. It will be obvious that during the reversing operation the pin 13 must not engage the groove 9. This pin is withdrawn by means of the spring in the device 12 or by means of its electromagnet as soon as the pin 15 begins to turn and move the element 7 downwards. When the conical surfaces of the element 7 and the clutch member 6 come into contact with each other the frictional force will maintain this contact and the current to the electromagnet of the device 14 can be switched off. The pin 15 then remains in the groove 9, but is freely turnable. The reversing device 14 need not assist in reversing the direction of rotation of the shaft 3 from astern to ahead operation, since the clutch is first thrown out of gear as described above whereupon the pin 70 13 is withdrawn and the spring 8 moves the element 7 into engagement with the clutch member 5.
If for some reason control current is not available the pin 15 can be turned manually 75 by means of a lever 16. The disengaging device and the reversing device must be electrically interconnected such that the pin 13 does not lock the element 7 while the pin tends to move the element into engagement with the clutch member 6.
The reversing gear can be somewhat simplified if the spring 8 is omitted and the lement 7 by its own weight assumes the normal position by engaging the clutch member 6. In this case, astern operation is obtained by engaging the element 7 with the member 5, and the direction of rotation of the. input shaft must be opposite as compared with the above described arrangement go90 or the propeller must be of the reversible pitch type.
The invention also comprises a simplified reversing gear which is manually operable and renders possible quick and smooth 95 reversing operation.
In motor boat engines, especially of the outboard motor type, there is often used a combined power and operating control for remote control of the engine. In control 100 systems of this type it may be difficult to obtain correspondence between the fixed stroke of the control device and the stroke of the clutch element. These difficulties are further increased as a result of change of the 105 stroke of the clutch element caused by wear and play in operation. The reversing gear provided by the simplified embodiment of the invention offers the advantage that the clutch element during the shifting operation 110 is acted upon by a positive force the magnitude of which is directly dependent on the force exerted on the control means, whereas the element after having been shifted is actuated by a resilient force which does not 115 prevent further displacement of the control device for adjusting the power control of the engine. In this case, the stroke of the clutch element is independent of the stroke of the control device. 120 The reversing gear illustrated in Figs. 2 to comprises an input shaft 21 having a bevel pinion 22 at one end. The pinion 22 is in permanent mesh with two bevel gear wheels 23 and 24 which engages the pinion at diametrically opposite points so as to be driven in opposite directions of rotation. The gear wheels 23 and 24 are mounted for free rotation about an output shaft 25, but; are axially non-displaceably mounted in a clutch 130 axis of which intersects the axis of the shaft 34 and extends through the point of the greatest radius of the eccentric disc. A ball loaded by the spring 39 is axially slidable in the bore 38 and abuts the bottom of the 70 V-shaped groove 36 in the above named intermediate position. Further, this groove and the eccentric disc are devised such that the eccentric disc 35 upon some turning movement from the intermediate position no 75 longer bridges the distance between the oblique lateral surfaoes 36' and 36" of the Vshaped groove 36, resulting in rthat the shafts 31 and 34 are enabled to make a limited turning movement relative each other. How.ver, in this case the spring biassed ball 40 is in contact with one of,the lateral surfaces 36' or 36" and the shift device as well as the clutch element 29 will consequently be retained in thel adjusted position by means of 85 a force defined by the compression of the spring 39 and the moment arm of the ball 40, whereas the operating device without obstacle can b,h turned further to perform other functions, such as increase of the fuel 90 supply to the engine.
According to a simplified embodiment of the invention as illustrated in Fig. 6, the shift device comprises a shaft 41 which extends into the clutch case and the inner end of 95 which by means of an eccentric pin 32 is received in ithe peripheral groove 33 of the clutch element 29 in, a manner similar to the above described embodiment. The end of the shaft 41 located outside the clutch case 100 carries an arm 42 which by means of a slot is divided into two prongs 42' and 42". The operating device comprises a link 44 which is articulated to a pivotally mounted operating lever 43 and is received between the prongs 105 42' and 42" by means. of a crosspin 45 the diameter of which equals the distance between said prongs. The link 44 is acted upon by a spring 46 which tends to keep the pin 45 in contact with the bottom of the 110 fork.
When the clutch element 29 assumeis its neutral position the pin 45 abuts the bottom of the fork. Upon turning of the operating lever 43 in either direction a shifting force 115 is transmitted without play to the shifting device. When the movement of the clutch element 29, and, consequently, the movement of the shaft device is stopped as a result of the clutch element coming into contact with 120 the clutch member 27 or 28 the operating lever can b3 swung additionally to perform other functions, for example fuel control in which case the cross pin 45 will slide outwardly along the prong 42' or 42" so as still 125 more to stretch the spring 46.
It will be seen that the above described arrangement results in a reversing gear having the same advantages as the embodiment described with reference to Figs. 2-5. The 130 case 26. The gear wheels 23 and 24 are secured to clutch members 27 and 28, respectively, which have opposed internal conical clutch surfaces which preferably are provided with one or more uninterrupted small-pitch threads. Between the clutch members 27 and 28 the output shaft 25 carries a clutch element 29 having axially outwardly-converging externally conical clutch surfaces adapted to cooperate with the conical clutch surfaces of the clutch members 27 and 28. The clutch element 29 is axially displaceable along the output shaft and within limit's rotatably connected thereto. The connecting means suitably comprises helical splines 30 on the output shaft between the gear wheels 23 and 24, and corresponding helical grooves in a central bore of the clutch element 29 such that the clutch element upon contact with one of the clutch members will be screwed to clutchengaging contact with said clutch member under the action of the frictional torque.
A shift device comprising a shaft 31 extends through the clutch case 26 at right angles to the output shaft 25. The inner end of the shaft 31 has an eccentric pin 32 which engages a peripheral groove 33 between the conical clutch surfaces of the clutch element 29. Turning movement of the shaft 31 consequently results in a displacement of the clutch element 29 from a central neutral position into engagement with the clutch member 27 or 28 of the gear wheel 23 or 24 whereby to transmit the torque of the input shaft to the output shaft 25 via the pinion 22 either by the gear wheel 23 and its clutch member 27 or the gear wheel 24 and the clutch member 28 and the clutch element 29.
To 'adapt the movement of the shift device to the movement of a combined power and operating control, the shift device is actuated by means of an operating device which comprise.s a shaft 34 that extends through the clutch case 26 parallel to the shaft 31 of the shift device. The shafts 31 and 34 are interconnected for common turning in opposite directions by means 'of an eccentric disc 35 secured to the shaft of the operating device.
In an intermediate position of the shafts 31 and 34 corresponding to the neutral position of the clutch element the eccentric disc 35 engages a V-shapAed groove 36 in the shaft 31 of the shift device such as without play to abut the two obliqu, lateral surfaces 36' and 36" of this groove. If the operating device is turned, for instance by means of an operating lever 37, the turning movement will be transmitted to the shift device 31,32 without play, the torque transmitted by the disc 35 to the shaft 31 being dependent on the force exerted on the operating lever. As a result, the shift device displaces the clutch element 29 in either direction.
The eccentric disc 35 has a bore 38 the 951,038 951,038 embodiment according to Fig. 6 is particularly suitable in combination with existing combined power and operating controls.
