Hydraulic actuating pin system

A hydraulic actuating pin system is disclosed with an actuating pin, clutch drum, spring and hydraulics. The clutch drum has a scalloped annulus with raised and lowered sections. The spring pushes the pin towards the scalloped annulus. When the pin extends into the lowered section, it prevents the clutch drum from rotating. The hydraulics can compress the spring and extract the pin to allow the clutch drum to rotate. The proximal end of the pin can include a head, and hydraulic pressure can move the head to compress the spring. When the pin is fully extended into the lowered section, the end of the pin can not touch the bottom of the lowered section. The hydraulics can include a one-way valve allowing flow from a pump source to the pin, and a pressure release orifice allowing controlled release of hydraulic pressure from the pin.

FIELD OF THE INVENTION

The present invention generally relates to the field of motorized machinery, and more specifically to a system and method for controlling rotation of a clutch drum during machine start-up.

BACKGROUND OF THE INVENTION

When coupling an implement to a machine where the implement is to be powered by an output shaft of the machine, it is desirable during startup to have the output shaft of the machine free to rotate about 60 degrees for coupling to the implement but not allow the output shaft to rotate more than 180 degrees from origin. It can be difficult to have the output shaft of the machine operate within these parameters under certain conditions. These parameters may vary for different machines and/or implements.

An exemplary condition where it is difficult for the machine engine powering the output shaft to operate within the above parameters is during cold start (for example, −30° C. or below). In some systems, a brake powered by a fluid pump is used to prevent the output shaft from rotating more than 180 degrees during start up. The fluid pump pulls fluid up a channel from a reservoir to engage the brake. During cold start conditions, the fluid can be very viscous and can take several seconds for the fluid pump to build brake pressure to pull the high viscous fluid up the channel and energize the brake system. So it may take several seconds for the brake volume to fill and apply any braking to the output shaft that has been running since start up.

One attempted solution to this problem is to have three pins equally spaced about the axis of the clutch center line. However, the output shaft can break these pins if the fluid pressure drops suddenly. Another disadvantage of this solution is that the piston and brake cone interface can be steel-on-steel which wears poorly and produces unwanted heat. An alternative design is to use steel piston and brake cone with roller balls instead of pins. In this alternative, the balls can wedge and create flat spots and produce a cyclic failure with the ball and ramp design. The common drawbacks with these attempted solutions to the “free” rotation and braking issues are: (1) whether it's a ball or pin, they will both fail with sudden loss of pressure; (2) steel-on-steel designs wear quickly; (3) the amount of braking pressure applied to the output shaft is only that of the Bellville springs utilized to push the piston back, and a high inertia implement can take minutes to spin down and risk snapping the pins if the steel-on-steel interface fails; and (4) the “free rotation” for coupling the implement is not actually free; in that there is constant pressure on the thrust bearing from the clutch Bellville springs.

It would be desirable to have a system that allows limited rotation of an engine output shaft to enable coupling of an implement to the output shaft while simultaneously preventing complete rotation of the output shaft. It would also be desirable to have such a system function in any conditions, including extreme cold, and to have such a system shutdown gracefully during a failure mode, such as a loss of hydraulic pressure.

SUMMARY

A hydraulic actuating pin system is disclosed that includes an actuating pin, a clutch drum, a spring and a hydraulic input. The actuating pin has a proximal end and a distal end. The clutch drum has a scalloped annulus extending circumferentially on a face of the clutch drum, the scalloped annulus having a raised section and a lowered section, the raised section extending away from the face of the clutch drum above the lowered section. The spring pushes the actuating pin towards the scalloped annulus of the clutch drum, and when the actuating pin extends into the lowered section of the scalloped annulus, the actuating pin prevents the clutch drum from rotating by preventing the raised section of the scalloped annulus from rotating below the actuating pin. The hydraulic input supplies hydraulic pressure to compress the spring and extract the actuating pin from the clutch drum and above the raised section of the scalloped annulus to allow the clutch drum to rotate without interference from the actuating pin.

The scalloped annulus of the clutch drum can include a plurality of raised sections separated by a plurality of lowered sections; each of the plurality of lowered sections can have substantially the same circumferential length, and each of the plurality of raised sections can have substantially the same circumferential length. The scalloped annulus can have three raised sections and three lowered sections.

The proximal end of the actuating pin can include a head, and the hydraulic pressure can move the head of the actuating pin to compress the spring and extract the actuating pin from the clutch drum. The spring can be coupled to the head of the actuating pin. The distal end of the actuating pin can include a distal face, and when the actuating pin is fully extended into the lowered section of the scalloped annulus of the clutch drum, the distal face of the actuating pin can not touch the bottom of the lowered section of the scalloped annulus of the clutch drum.

A hydraulic actuating pin system is disclosed that includes an actuating pin, a clutch drum, a spring and a hydraulic system controlling hydraulic pressure applied to compress the spring. The clutch drum has a scalloped annulus extending circumferentially on a face of the clutch drum, the scalloped annulus having a raised section and a lowered section, the raised section extending away from the face of the clutch drum above the lowered section. The spring pushes the actuating pin towards the scalloped annulus of the clutch drum, and when the actuating pin extends into the lowered section of the scalloped annulus, the actuating pin prevents the clutch drum from rotating by preventing the raised section of the scalloped annulus from rotating below the actuating pin. The hydraulic system controls hydraulic pressure causing the spring to compress and extracting the actuating pin from the clutch drum and above the raised section of the scalloped annulus to allow the clutch drum to rotate without interference from the actuating pin.

The hydraulic system can include a pump source controlling supply of hydraulic pressure, and a one-way flow valve between the pump source and the actuating pin. The one-way flow valve allows flow from the pump source to the actuating pin and blocks flow from the actuating pin to the pump source. The hydraulic system can also include a pressure release orifice in parallel with the one-way flow valve. The pressure release orifice allows controlled release of hydraulic pressure from the actuating pin. The hydraulic system can also include an accumulator hydraulically coupled to the actuating pin. The one-way flow valve allows flow from the pump source to the actuating pin and the accumulator and the pressure release orifice allows controlled release of hydraulic pressure from the actuating pin and the accumulator.

A hydraulic actuating pin system is disclosed that includes an actuating pin, a clutch drum, a spring and a hydraulic system. The clutch drum has a scalloped annulus extending circumferentially on a face of the clutch drum, the scalloped annulus having a plurality raised sections and a plurality of lowered sections, each of the plurality of raised sections extending away from the face of the clutch drum above the plurality of lowered sections. The spring pushes the actuating pin towards the scalloped annulus of the clutch drum, and when the actuating pin extends into a particular lowered section of the plurality of lowered sections of the scalloped annulus, the actuating pin prevents the clutch drum from rotating by preventing the adjacent raised sections of the plurality of raised sections of the scalloped annulus from rotating below the actuating pin. The hydraulic system controls hydraulic pressure applied to compress the spring, the hydraulic pressure causing the spring to compress and extracting the actuating pin from the clutch drum and above the plurality of raised sections of the scalloped annulus to allow the clutch drum to rotate without interference from the actuating pin.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of the novel invention, reference will now be made to the embodiments described herein and illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the novel invention is thereby intended, such alterations and further modifications in the illustrated devices and methods, and such further applications of the principles of the novel invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the novel invention relates.

FIG. 1shows an exemplary embodiment of a front end100of a machine engine with a hydraulic actuating pin system102, andFIG. 2shows a closer schematic of an exemplary embodiment of the hydraulic actuating pin system102. The exemplary system102includes an actuating pin202, a spring204, a plug206and a clutch drum210.FIG. 4shows the exemplary clutch drum210by itself. The exemplary clutch drum210includes a scalloped annulus212with three lowered sections214extending circumferentially separated by three raised sections216. The lowered sections214can be substantially even with the surface of the clutch drum210with the raised sections216extending above the surface of the clutch drum210; or the lowered sections214can be below the surface of the clutch drum210with the raised sections216substantially even with the surface of the clutch drum210; or the lowered sections214and the raised sections216can be above and/or below the surface of the clutch drum210with the lowered sections214being relatively lower than the raised sections216. In the exemplary clutch drum210ofFIGS. 2 and 4, the lowered sections214and the raised sections216are above the surface of the clutch drum210with the lowered sections214being relatively lower than the raised sections216. In the embodiment ofFIG. 4, the lowered sections214and the raised sections216have substantially equal circumferential lengths which allows the clutch drum to rotate approximately 60° when the actuating pin102extends inside one of the lowered sections214, and to rotate up to 120° if the actuating pin102falls on one of the raised sections216and then rotates the length of the raised section before extending into an adjacent lowered section214. The clutch drum210can include more or less raised and lowered sections214,216depending on the desired distance of rotation when the actuating pin202is engaged/extended.

FIG. 3shows a cross-section of the actuating pin system102along with a system hydraulic line320. The actuating pin202includes a distal face302and a proximal head304at the distal and proximal ends, respectively, of the actuating pin202. The actuating pin202is positioned to extend towards and retract from the scalloped annulus212of the clutch drum210.

The actuating pin202is controlled by a hydraulic system using the hydraulic line320. When there is no hydraulic pressure, the spring204is uncompressed and pushes the actuating pin202towards the clutch drum210, and when the actuating pin202extends into one of the lowered sections214it prevents the clutch drum210from moving beyond the ends of the lowered section214into which the actuating pin202is extended. The system can be configured so that when the actuating pin202extends into one of the lowered sections214, the distal face302of the actuating pin202does not touch the clutch drum210in the lowered section214. During operation, hydraulic pressure introduced through the hydraulic line320enters a retraction area224and pushes against the proximal head304of the actuating pin202to compress the spring204and move the actuating pin202away from the clutch drum210, out of the lowered section214and above the raised sections216so that the clutch drum210can freely rotate.

FIG. 5shows a schematic of an exemplary embodiment of an actuating pin system and hydraulic circuit500. The hydraulic circuit500includes a pump source502that provides hydraulic pressure to a brake system504and to an actuating pin system506. The hydraulic system500can also include a system pressure regulating valve508, and an accumulator516. The actuating pin system506includes a pin valve body510with a one-way flow valve512and a pressure release orifice514. When the hydraulic system500is not providing pressure, the spring204pushes the actuating pin202into one of the lowered sections214of the clutch drum210which only allows limited rotation of the clutch drum210. When the hydraulic system is activated, the source502pumps fluid through the one-way valve512through the hydraulic line320and into the retraction area224below the proximal head304of the actuating pin202. If the hydraulic system500also includes the accumulator516, the source502of the activated hydraulic system500also pumps fluid through the one-way valve512through the hydraulic line320and into the accumulator516. As hydraulic pressure increases in the retraction area224, the proximal head304of the actuating pin202compresses the spring204and retracts the actuating pin202from the clutch drum210and above the raised sections216to allow free rotation of the clutch drum210. The system pressure from the source502energizes the actuating pin202, retracting the actuating pin202away from the face of the clutch plate210for free rotation of the clutch drum210.FIG. 5also shows a leakage path520back to sump if there is leakage of the hydraulic fluid around the head304of the actuating pin202.

If system pressure is lost for some reason, the actuating pin202remains extracted from the clutch drum210and slowly returns towards the clutch drum210controlled by the pressure release orifice514. If hydraulic pressure ceases, the hydraulic fluid in the retraction area224and the accumulator516(if included) will pass back through the hydraulic line320and bypass the one-way valve512through the pressure release orifice514. This enables the spring204to uncompress and push the actuating pin202into one of the lowered regions214of the clutch drum210. The pressure release orifice514and accumulator516can be sized to control the speed of reinsertion of the actuating pin202into the clutch drum210.

The actuating pin202can be designed such that the distal face306does not contact the bottom of the lowered sections214of the clutch drum210when the actuating pin202is fully extended, thereby providing real free rotation of the clutch drum210within the bounds set by the lowered sections214.

There can be more or less than three lowered sections and raised sections depending on the desired movement of the clutch drum210when the actuating pin202is extended. In addition, or alternatively, the circumferential lengths of the lowered sections and raised sections can be configured to control the movement of the clutch drum210when the actuating pin202is extended.