Patent Application
20140174142
The present invention relates generally to knurling devices, and, more particularly, to an improved end-knurling device for rolling a knurl pattern on a marginal end portion of a workpiece.
Knurling devices are, of course, known.
One example of a prior art knurling device is shown and described in U.S. Pat. No. 8,250,893 B2.
Another type of prior art knurling device is made by Form Roll Die Company, and, more particularly, by Stafford Special Tools, 88 Webster Place, Worcester, Mass. 01603.
However, to make certain adjustments on this device, as many as twenty-three screws and three bolts must be removed and/or adjusted. This required as much as a day of down-time, and also required a highly-skilled operator to make the adjustments.
A structurally-similar thread-rolling attachment is shown and described in U.S. Pat. No. 6,988,388 B2.
Accordingly, it would be generally desirable to provide an improved knurling device that would be simple in structure, easy to use, and easy to adjust.
With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for purposes of illustration and not by way of limitation, the present invention broadly provides an improved knurling device (20).
The improved knurling device broadly includes: a body (21) having an axis of elongation (x-x), and having a first part (22) and a second part (23); the body first part having axially-spaced annular front and center plates (24, 25, respectively); the body second part being mounted on the center plate and being selectively rotatable about the device axis (x-x) relative to the center plate; a plurality of knurl rolls (26, 26, 26) mounted on the body first part between the front and center plates, the radial spacing of the knurl rolls from the axis being a function of the relative position between the first and second body parts; an arbor (28) axially mounted on the body second part and biased to move toward the front plate; a master pinion (29) rotatably mounted on the arbor and having an outer surface adapted to selectively engage the outer surface of each of the knurl rolls; and wherein the end of a rotating workpiece (W) is adapted to be axially inserted through the front plate central opening and then moved toward the body second part to first accelerate the knurls to the surface speed of the workpiece, and then to progressively roll a knurl pattern on the outer surface of the workpiece as the workpiece is moved toward further into the improved device.
The improved device may further include: a plurality of pins (45, 45, 45), each pin having a front marginal end portion journalled on the front plate, having an eccentric portion (51), and having a rear portion penetrating the center plate and having a rearward distal marginal end portion extending beyond the center pate, and wherein a knurl roll is rotatably mounted on the eccentric portion.
A carbide bushing (112) may be positioned between the eccentric portion and the knurl roll.
Each knurl roll is adapted to rotate relative to its associated bushing, and wherein each bushing is adapted to rotate relative to the pin eccentric portion about which it is mounted.
Each pin may have an axis of elongation, and wherein each pin axis may be arranged at an angle with respect to a line parallel to the body axis.
The radial spacing between the pin axis and the body axis may be less proximate the front plate than it is proximate the center plate. In one form, this angle may be about 0.5°.
A toothed sector or gear (58) may be mounted on the distal marginal end portion of each pin for rotation therewith.
The body second part may have a toothed portion engaging each toothed portion.
In a preferred form, the body second part toothed portion is a ring gear (72).
The improved device may further include at least one riser (33, 33, 33) positioned between the front and center plates for maintaining the spacing between the front and center plates.
A first fastener (35) may act between the front plate and riser.
The body second part may have an angular slot (73, 73, 73), and a second fastener (30, 30, 30) may act between the body second part and the riser, with a portion of each second fastener penetrating a respective slot.
The second fasteners (30, 30, 30) may be selectively loosened to permit relative rotation between the body first and second parts about the axis, and may be selectively tightened to prevent relative rotation between the body first and second parts.
The master pinion (29) may be rotatably mounted on the arbor.
The body second part may have a rearwardly-facing abutment surface (82), and the arbor may have a stop surface (90) arranged to face toward the body second part abutment surface for limiting forward movement of the arbor relative to the body.
The improved device may further include a sleeve (74) positioned between the body second part and the arbor, and the abutment surface (82) may be mounted on the sleeve. The axial position of the sleeve relative to the body second part may be adjustable.
A spring retainer (97) may be mounted on the adjustment sleeve.
A spring (96) may act between the spring retainer and the arbor.
Accordingly, the general object is to provide an improved knurling device.
Another object is to provide an improved end-knurling device that may be adjusted more simply than prior art devices.
These and other objects and advantages will become apparent from the foregoing and ongoing specification, the drawings, and the appended claims.
At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this invention. As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.
Turning now to the drawings, and more particularly to
The improved device is shown as having an assembled body, generally indicated at 21, having a horizontal axis of elongation x-x. The body has a first part 22 and a second part 23. The first part 22 has axially-spaced annular vertical front and center plates 24, 25, respectively. The body second part 23 is operatively mounted on the center plate 25, and is adapted to be selectively rotated about axis x-x relative to the center plate.
A plurality of knurl rolls, severally indicated at 26, are mounted on the body first part between the front and center plates. These knurl rolls have been omitted from
A piston-like arbor 28 is axially mounted on the body second part and is biased to move toward the front plate. A master pinion 29 is mounted on the right marginal end portion of the arbor, and has its outer surface engaging the outer surface of each of the knurl rolls to maintain the relative angular positions and timing of the knurl rolls.
One end of a rotating workpiece W is adapted to be axially inserted through the front plate central opening, and moved rearwardly relative thereto to first accelerate the knurls to the surface speed of the rotating workpiece, and to thereafter begin to cause the knurl rolls to progressively roll a knurl pattern on the outer surface of the workpiece as the arbor is progressive displaced further into the device.
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Three circumferentially-spaced eccentric roll pins, severally indicated at 45, are mounted on the body front part between the front and center plates. As best shown in
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A compressed coil spring 96 acts between a spring retainer 97 and arbor flange surface 88.
A master pinion 29 having a knurled outer surface 98 is slipped over the forwardly-extending elongated neck (defined by cylindrical surface 93) that extends rightwardly from the arbor, and is secured thereto by means of a washer 99 and a screw 100 that is matingly received in arbor tapped hole 95.
The spring retainer 97 is shown as having an annular vertical left end face 101, an annular vertical right end face 102, an outer surface that sequentially includes a hexagonal portion 103 extending rightwardly from the outer margin of left end face 101, and an externally-threaded portion 104 continuing rightwardly therefrom to join the outer margin of right end face 102. The spring retainer is shown as also having a stepped axial through-bore which sequentially includes (from left-to-right): a horizontal cylindrical surface 105 extending rightwardly from the inner margin of left end face 101, a leftwardly-facing annular vertical surface 106, and a horizontal cylindrical surface 108 continuing rightwardly therefrom to join the inner margin of right end face 102. When the device is assembled, spring retainer threads 104 matingly engage adjustment sleeve threads 80, and the spring 96 is compressed between spring retainer right end face 102 and arbor flange surface 88.
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The device is assembled as shown in the drawings. A suitable lubricant is provided by suitable means (not shown) to the rear end of the device. This lubricant passes through the spring retainer, and flows into the chamber in which spring 96 is arranged. From there, it flows through the arbor bore and the radial opening (not shown) to lubricate the various rolls and moving parts. The device is mounted as a stand-alone device, or may be mounted on a suitable machine tool.
The sequence of operation is comparatively illustrated in
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After the knurl pattern has been rolled on the workpiece, the still-rotating workpiece may simply be withdrawn from the device, this being indicated by the direction and magnitude of arrow 123 in
To adjust the penetration depth of the knurl rolls, an operator need only loosen fasteners 30, 30, 30 and rotate the shank 32 relative to the body first part. As this occurs, the gears 58, 58, 58 rotate about their respective axes, and cause pins 45, 45, 45 to rotate. Since the knurl rolls are rotatably mounted on the pin eccentric surfaces 51, such rotation of the pins causes a change in the radial distance from the device axis to the knurl rolls. The direction of relative rotation between shank 32 and the body first part determines whether this radial distance is increased or decreased. Once in the proper angular position, fasteners 30, 30, 30 may be retightened to securely hold the device in the set-depth.
Therefore, the present invention broadly provides an improved knurling device (20) that includes: a body (21) having an axis of elongation (x-x), and having a first part (22) and a second part (23); the body first part having axially-spaced annular front and center plates (24, 25, respectively); the body second part being mounted on the center plate and being selectively rotatable about the device axis (x-x) relative to the center plate; a plurality of knurl rolls (26, 26,26) mounted on the body first part between the front and center plates, the radial spacing of the knurl rolls from the axis being a function of the relative position between the first and second body parts; an arbor (28) axially mounted on the body second part and biased to move toward the front plate; a master pinion (29) rotatably mounted on the arbor and having an outer surface adapted to selectively engage the outer surface of each of the knurl rolls; and wherein the end of a rotating workpiece (W) is adapted to be axially inserted through the front plate central opening and then moved toward the body second part to first accelerate the master pinion to the angular speed of the workpiece, and then to progressively roll a knurl pattern on the outer surface of the workpiece as the workpiece is moved toward further into the improved device.
Upon information and belief, the present invention possesses a number of points of patentable distinction over the current state of the art. These relate to: (1) the use of the master pinion, (2) the use of a spring-loaded master pinion arbor, (3) the use of a 0.5° roll axis taper, (4) the use of an axially-positionable sleeve 78 with abutment surface 28 to selectively adjust the rightwardmost position of the master pinion, and (5) the use of a single adjustment/motion to co-ordinate the penetration amount of all three role axes using the ring gear, gear segments and eccentric pins, while maintaining the knurl roll angular synchronization or timing.
As to the first point, the use of a central master pinion to engage the outer working surfaces of the knurls provides relative rotational positioning or timing of the three knurl rolls. Moreover, the invention uses a central master pinion that is selectively engageable with the working surfaces of the rolls, such that the master pinion may disengage during the work cycle to expose the full workface of the rolls, and to allow the knurling of a workpiece that is substantially longer that the axial lengths of the knurl rolls.
As to the second point, the use of a spring-loaded master pinion arbor provides a mechanism for automatically re-engaging the master pinion when the workpiece is withdrawn, and re-establishing the relative timing of the rolls.
As to the third point, the use of a 0.5° roll axis taper biases the bulk of the deformation to the outboard (right) end of the knurl width. This allows for the workpiece to be full formed very close to a shoulder, with little or no taper along the length of the resultant workpiece knur. This also allows for knurling roll tooling to be of any substantial width to be essentially “reversible”. Since the bulk of the work and wear is biased to only the leading edge of the knurl, the knurl can be flipped so that the previously-trailing edge can be re-installed as a second leading edge, thereby effectively doubling the useful life of the tooling. The use of the 0.5° angle allows for a variable gear mesh diameter between the leftmost and rightmost ends of the knurl roll workface. This feature is used in conjunction with an axially-positionable sleeve (described infra) to adjust gear backlash.
With respect to the fourth point, the use of an axially-positionable sleeve with an abutment sleeve can be sued to selectively adjust the rightwardmost position of the master pinion. Used in conjunction with the variable gear mesh diameter established by the 0.5° roll pin taper angle, this feature allows the user to increase or decrease the gear mesh backlash between the master pinion and the knurl rolls. This ability to adjust the backlash is critical to ensuring the proper rolling action of the knurls, without binding the “gear train” that keeps the knurls angularly in synchronism with one another, so that each tooth on each successive knurl falls into the groove partially created by the previous knurl, as the part rotates.
Finally, with respect to the fifth point, the use of a single adjustment/motion coordinates the extent of penetration of all three roll axes using the ring gear, gear segments and eccentric pins, while maintaining the angular synchronism of all three knurl rolls. Single-motion penetration adjustment exists on some prior art thread rolling heads, but, upon information and belief, has never been sued in conjunction with rolls that have had to be synchronized for more than one revolution in order to function. This is an exceedingly difficult thing to do because a timing gear train normally operates of a fixed mesh diameter, but to adjust the penetration amount, one must vary the mesh diameter.
The present invention contemplates that many changes and modifications may be made. The sleeve and arbor may be formed separately, as described, or may be formed integrally, as desired. While it is presently preferred that the roll pin axes are inclined by some small angle (i.e., 5°) such that the forward end of the knurl rolls bites more deeply into the workpiece that the rearward end thereof, this is not invariable. The particular knurl pattern may be changed by changing the master pinion and the knurl rolls.
The spacers may be formed integrally with plate 24 or plate 25, as desired. The force supplied by spring 96 may be supplemented or replaced by fluid pressure magnetic force, or some other means
The bushings may be removed entirely, allowing the knurl rolls to rotate directly on the eccentric roll pins.
Plate 22 and spacers 33 may be eliminated, and roll pins 45 may be adapted to hold the lateral position of the knurl rolls, allowing for an “outboard” configuration to knurl directly adjacent to large diameter shoulders on the workpiece.
Therefore, while the presently-preferred form of the improved end-knurling device has been shown and described, and several possible modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit of the invention, as defined and differentiated by the following claims.
