Vibration damper for rotating shaft

Abstract

A vibration damper has a pair of rollers that engage a shaft rotating about its longitudinal axis while being supported at its ends on centers. The rollers transmit shaft vibrations to the piston rod of a hydraulic or pneumatic cylinder in such a manner that the piston rod dampens the vibrations.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] Steel shafts, such as an axle, are commonly finished by being mounted on a pair of rotating centers. The rotating shaft sometimes generates harmonic vibrations. Such vibrations are undesirable for achieving a precision finish on the shaft surface.

[0003] The broad purpose of the present invention is to provide a damping device for reducing the vibrations of a rotating shaft. In the preferred embodiment of the invention, a pneumatic or a hydraulic power cylinder is mounted on a base, adjacent the rotating position of the shaft. The axis of the cylinder is aligned with and at a right angle to the centerline of the shaft. The piston rod is connected to a clevis which in turn is connected to a slide plate. The slide plate moves with the piston rod and either toward or away from the shaft. A pair of pivotal arms, mounted on the base, are cammed by the slide plate.

[0004] Rollers mounted on the outer ends of the arms engage the workpiece, accommodating any misalignment of the workpiece. The slide plate carries a pair of cam rollers that are mounted in cam slots in the two arms. The arrangement is such that any vibration of the workpiece is transmitted through the arms, the plate slide and to the cylinder which dampens the vibrations.

[0005] Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.

DESCRIPTION OF THE DRAWINGS

[0006] The description refers to the accompanying drawings in which like reference characters refer to like parts throughout the several views and in which:

[0007] FIG. 1 is an elevational view of a vibration damper illustrating the preferred embodiment of the invention;

[0008] FIG. 2 is a view similar to FIG. 1, but showing some internal components in phantom;

[0009] FIG. 3 is an enlarged view of one of the arms as seen from the left-side of FIG. 2;

[0010] FIG. 4 is an enlarged view as seen along line 4 of FIG. 2;

[0011] FIG. 5 is an enlarged view as seen along line 5 of FIG. 2;

[0012] FIG. 6 is an enlarged view as seen along line 6 of FIG. 2;

[0013] FIG. 7 is a plan view of the base separated from the remainder of this device; and

[0014] FIG. 8 is an elevational view of the slide plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] Referring to the drawings, FIGS. 1 and 2 illustrate a preferred vibration damper 10. The vibration damper includes a cushioning pneumatic power cylinder 12, such as a global series cylinder, double acting, single rod model, mounted in a vertical position on a suitable mounting bracket 14, illustrated in phantom. The power cylinder has a pair of ports 16 and 18 connected to a source of pneumatic pressure, not shown, for reciprocating an internal piston, not shown. A clevis 20 is attached to a piston rod 21 to reciprocate toward or away from the centerline of an elongated workpiece 22. The workpiece may be a shaft or an axle undergoing a metal finishing operation. The levis is movable along an axis 24 either toward or away from the center of workpiece 22.

[0016] Referring to FIGS. 4 and 7, a right angle base 26 has one wall 28 attached by fastener means 30 to the upper end face of the cylinder. Wall 28 has an opening 32 to accommodate the up and down movement of the clevis.

[0017] Referring to FIGS. 4-6 and 8, a slide plate 34 has a lower end connected to the clevis by a pin 36 such that as the clevis is moved by the power cylinder toward the workpiece, the slide plate moves an equal distance.

[0018] The slide plate has a vertical slot 38 aligned with axis 24 of piston rod 21.

[0019] Referring to FIG. 4, a shoulder screw 40 and a jam nut 42 are supported in a horizontal position to base 26. Screw 40 extends through slot 38 in the slide plate to the base.

[0020] Referring to FIGS. 2, 5 and 8, the slide plate has a pair of openings 44 and 46 located on opposite sides of slot 38. A pair of dowel (pivot) pins 48 and 50 are mounted in the two openings 46 and 44, respectively. Pins 48 and 50 are both mounted on the base.

[0021] Elongated pivot arms 52 and 54 are pivotally mounted on pivot pins 48 and 50, respectively. Arm 52 is pivotally movable from a lower release position, illustrated at A in FIG. 1, to an upper work-engaging position, illustrated in phantom at B. Similarly, arm 54 is pivotally movable from a lower release position C to an upper work-engaging position D. Arm 52 has a cam slot 56. Arm 54 has a cam slot 58. Cam slots 54 and 56 are each aligned with the center of their respective pivot pins.

[0022] Referring to FIGS. 2 and 6, the slide plate carries a cam roller 60 which is disposed in cam slot 58. As the slide plate rises toward workpiece 22 in a vertical motion, as viewed in FIG. 2, cam roller 60 rises along a linear path of motion from a lower position, illustrated in phantom in FIG. 2, toward an upper position also illustrated in phantom. Cam roller 60 moves in cam slot 58, camming arm 54 from its lower position toward its upper position.

[0023] Referring to FIGS. 1 and 2, a pair of floppy brackets 62, only one shown, are pivotally mounted by a pin 63 on the outer end of pivot arm 54. Workpiece-engaging rollers 64 and 66 are mounted in a spaced position on the outer end of brackets 62 by roller pins 68 and 70, respectively. Dowel pin 72, carried by the brackets, engages a channel 74 carried on arm 54 to limit the swing of rollers 64 and 66 about pin 63.

[0024] Referring to FIGS. 2 and 6, the slide plate has a second roller or cam follower 75 carried in cam slot 56, camming arm 52 from a lower position, illustrated in solid in FIG. 2, to a raised position, also illustrated in phantom toward the workpiece.

[0025] Referring to FIGS. 2 and 3, a second pair of floppy brackets 76 and 77, similar to brackets 62, are mounted by a pivot pin 78 on the outer end of arm 52. The brackets carry a pair of rollers 80 and 82 on pins 84 and 86, respectively, for engaging the workpiece. A dowel pin 88 carried by brackets 76 and 77 engages a channel-shaped cut-out in arm 52 to limit the pivotal motion of rollers 80 and 82 as they swing about the outer end of the arm 52.

[0026] Thus it is to be understood that I have described a vibration-dampening device for reducing the vibration of an elongated rotating workpiece 22. Usually the workpiece will be delivered to a mounting position between arms 52 and 54, and placed on rotating centers. Arms 52 and 54 are pivoted toward the workpiece until rollers 80, 82, 64 and 66 engage the workpiece at 900 intervals, as illustrated in FIG. 2.

[0027] The floppy brackets which carry rollers 80, 82, 64 and 66 permit the two arms to be self-aligning to accommodate irregularities in the workpiece shape.

[0028] In use, the damper is mounted, at a suitable location along a workpiece. The piston rod moves the slide plate in a vertical motion, rising to move the rollers either toward the workpiece, or lowering to move the arms toward this lower position to separate the cam rollers from the workpiece. Any vibration of the workpiece is transmitted through the arms and slide to the piston rod where the vibration is cushioned.

Claims

1. A vibration damper for an elongated workpiece rotating about an axis, and vibrating in a direction lateral to said rotating axis, comprising: at least one workpiece-engaging roller supported for rotation about an axis parallel to a workpiece-rotating axis; mechanical means connected to said roller for moving the roller into engagement with the rotating workpiece to rotate therewith, and for moving with the workpiece in a direction lateral to said rotating axis as the workpiece is vibrating; a fluid cylinder having a reciprocally, resiliently mounted piston rod, movable with respect to said cylinder; said mechanical means being connected to said piston rod and said roller to resist a radial motion of the roller carried by the workpiece.

2. A vibration damper as defined in claim 1, in which the piston rod reciprocates along an axis that intersects the rotating axis of the workpiece.

3. A vibration damper as defined in claim 1, including a plurality of rollers each supported for engaging the workpiece, said mechanical means being operative to move said plurality of rollers toward the workpiece, and being connected to the piston rod to resist a vibrational movement of the workpiece.

4. A vibration damper as defined in claim 3, in which the plurality of rollers engage the workpiece in equal angularly spaced locations about the workpiece.

5. A vibration damper for an elongated workpiece rotating about an axis and moving in a vibrational movement in a direction lateral to said rotating axis, comprising: a base; a cylinder mounted on the base and having a piston rod movable in a direction transverse to the rotating axis of a workpiece; a slide plate connected to the piston rod so as to be movable therewith; a first arm, and first pivot means connecting the first arm to the base for a pivotal motion, the first arm having a camming slot; a first cam roller carried by the slide plate and received in the camming slot of the first arm, such that as the slide plate moves toward the workpiece, the first arm swings along a first path of motion about said pivot means toward the workpiece; a first floppy bracket, and pivot means connecting the first floppy bracket to the first arm to swing the arm toward the workpiece as the first arm swings in said first path of motion; a pair of spaced rollers carried on the first floppy bracket to engage the workpiece on a first side thereof; a second arm and second pivot means connecting the second arm to the base for a pivotal motion, the second arm having a camming slot; a second cam roller carried by the slide plate and received in the camming slot of the second arm such that as the slide plate moves toward the workpiece, the second arm swings along a second path of motion about said second pivot means toward the workpiece; a second floppy bracket and pivot means connecting the second floppy bracket to the second arm to move toward the workpiece as the second arm swings in said second path of motion; and a pair of spaced rollers carried on the second floppy bracket to engage the workpiece on a second side thereof whereby a vibrational movement of the workpiece is transmitted from the rollers on the floppy brackets to the first arm and the second arm, and then to the slide plate and the piston rod such that the piston rod resists said vibrational motion.