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Title:
IMPROVED PARTS AND SUBASSEMBLIES FOR SELF-REVERSING TAPPING ATTACHMENTS
Document Type and Number:
WIPO Patent Application WO/1999/039856
Kind Code:
A1
Abstract:
A self-reversing tapping attachment (10) comprises a tap holding spindle (30), a forward drive member (50) for imparting forward drive to the tap holding spindle (30), a reverse drive member (84) for imparting reverse drive to the tap holding spindle (30), the forward drive member (50) and the reverse drive member (84) including at least one receptacle (59) for receiving at least one detachably attachable drive spline (53) and a screw arrangement (79) for detachably attaching drive splines (53) to the forward drive member (50) and the reverse drive member (84).

Inventors:
Johnson, Allan S. (3860 Thompson Lake Road Harrison, ID, 83833, US)
Application Number:
PCT/US1999/002851
Publication Date:
August 12, 1999
Filing Date:
February 09, 1999
Export Citation:
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Assignee:
THE TAPMATIC CORPORATION (802 Clearwater Loop Post Falls, ID, 83854, US)
Johnson, Allan S. (3860 Thompson Lake Road Harrison, ID, 83833, US)
International Classes:
B23B47/14; B23G1/46; (IPC1-7): B23B47/14
Foreign References:
US3717892A
US4277209A
US4832542A
US5131794A
Attorney, Agent or Firm:
Evanns, Joseph R. (119 N. San Vicente Boulevard #206 Beverly Hills, CA, 90211, US)
Download PDF:
Claims:
WHAT IS CLAIMED IS: Claim
1. A selfreversing tapping attachment comprising: (1) tap holding spindle means for holding a tap; (2) drive means for imparting forward rotation and reverse rotation to said tap holding spindle means, said drive means including at least one receptacle for receiving at least one detachably attachable drive spline member; and (3) means for securing said at least one drive spline member in detachable attachment to said drive means.
2. Claim.
3. The invention as set forth in Claim 1 further including at least one drive spline member detachably attachable with said drive means in said at least one receptacle.
4. Claim.
5. The invention as set forth in Claim 2 wherein substantially the entirety of said drive spline member is nestable in said receptacle.
6. Claim.
7. The invention as set forth in Claim 2 wherein said at least one drive spline member includes a contact portion for imparting rotation for said tap holding spindle means.
8. Claim.
9. The invention as set forth in Claim 3 wherein said at least one drive spline member includes a contact portion for imparting rotation for said tap spindle holding means.
10. Claim.
11. The invention as set forth in Claim 3 wherein said at least one drive spline member includes means for connecting to said securing means to attach said at least one drive spline member to said drive means..
12. Claim.
13. The invention as set forth in Claim 4 wherein said contact portion includes at least one arcuate portion.
14. Claim.
15. The invention as said forth in Claim 4 wherein said contact portion includes at least two contact areas.
16. Claim.
17. The invention as set forth in Claim 8 wherein said at least two contact areas are substantially symmetrical.
18. Claim.
19. The invention as set forth in Claim 2 wherein at least a portion of said drive spline member is harder than at least a portion of said drive means.
20. Claim.
21. The invention as set forth in Claim 7 wherein said at least one arcuate portion of said at least one drive spline member includes a concave curvature.
22. Claim.
23. The invention as set forth in Claim 2 wherein at least a portion of said at least one drive spline member is treated for increased hardness.
24. Claim.
25. The invention as set forth in Claim 12 wherein said treated portion of said drive spline member is coated with a material such as titanium.
26. Claim.
27. The invention as set forth in Claim 2 wherein said drive spline member is fabricated by machining.
28. Claim.
29. The invention as set forth in Claim 2 wherein said drive spline member is fabricated by forging.
30. Claim.
31. The invention as set forth in Claim 2 wherein said drive spline member is fabricated by being sintered.
32. Claim.
33. The invention as set forth in Claim 1 wherein said means for securing said drive member comprises at least one screw hole in said at least one drive spline member and at least one screw access in said drive means, said at least one screw hole and said at least one screw access being alignable for placement therein of at least one securing screw..
34. Claim.
35. The invention as set forth in Claim 17 wherein said drive means comprises at least one forward drive member for imparting forward drive and at least one reverse drive member for imparting reverse drive.
36. Claim.
37. The invention as set forth in Claim 17 further including at least one securing screw for securing engagement with said at least one drive spline member through said screw access.
38. Claim.
39. The invention as set forth in Claim 19 wherein said at least one securing screw is securingly engaged with said at least one drive spline member.
40. Claim.
41. A selfreversing tapping attachment comprising: (1) tap holding spindle means for holding a tap; (2) drive means for imparting forward rotation and reverse rotation to said tap holding spindle means; and (3) at least one drive retainer member for holding at least one drive spline member and secureable in detachable attachment with said drive means.
42. Claim.
43. The invention as set forth in Claim 21 wherein at least one drive spline is mountable on said drive spline retainer member.
44. Claim.
45. The invention as set forth in Claim 21 wherein said drive spline retainer member includes a plurality of drive splines mounted thereon.
46. Claim.
47. The invention as set forth in Claim 21 wherein said drive means includes at least one receptacle for receiving said drive spline retainer member..
48. Claim.
49. The invention as set forth in Claim 21 further including means for securing said drive spline retainer member in detachable attachment to said drive means..
50. Claim.
51. The invention as set forth in Claim 25 wherein said means for securing said drive spline retainer member in detachable attachment to said drive means comprises at least one screw hole in said drive spline retainer member and at least one screw access in said drive means, said at least one screw hole and said at least one screw access being alignable for placement therein of at least one securing screw.
52. Claim.
53. The invention as set forth in Claim 22 wherein at least a portion of at least one said drive spline on said drive spline retainer member is harder than at least a portion of said drive means.
54. Claim.
55. The invention as set forth in Claim 22 wherein at least a portion of at least one said drive spline on said drive spline retainer member is treated for increasing hardness.
56. Claim.
57. The invention as set forth in Claim 28 wherein said treated portion of at least one said drive spline member is coated with a material such as titanium.
58. Claim.
59. The invention as set forth in Claim 22 wherein at least one drive spline on said drive spline retainer member is machined.
60. Claim.
61. The invention as set forth in Claim 22 wherein at least one drive spline on said drive spline retainer member is forged.
62. Claim.
63. The invention as set forth in Claim 21 wherein at least one drive spline on said drive spline retainer member is sintered.
64. Claim.
65. The invention as set forth in Claim 21 wherein said drive means comprises at least one forward drive member for imparting forward drive to said tap holding spindle member and at least one reverse drive member for imparting reverse drive to said tap holding spindle means..
Description:
IMPROVED PARTS AND SUBASSEMBLIES FOR SELF-REVERSING TAPPING ATTACHMENTS BACKGROUND OF THE IN 1 Field of the Inventton The Invention relates and certains to seif-reversmg tapping attachments,. e., self-reversing tools which carry taps for threading holes and are driven by a dnving machine or a power center, and to components for such tools.

2. Description of the Prior Art The field of the invention and the pnor art are exemplified in the field of self-reversing tapping attachments by reference to pnor patents assigned to the assignee of the instant application. These include: U. S. Patent Nos. 3,999,642 : 4. 014.421; 4,566.829 ; 4, 705, 437 ; 5, 203, 651 ; 5. 209, 616 ; and 5,213,413, and 5,628,923 and patents cited therein. together with a provisional patent application filed August 26.1997, all of which are hereby incorporated by reference herein.

The aforesaid disclose and claim tapping attachments including a tap holding spindle and simultaneously rotating forwara ana reverse dnvers, the spindle being freely floating and moveable axially with respect to the forward and reverse drivers. Under forward drive in which the tap holder spindle is driven by the forward driver, the tap threads a hole being tapped in the workpiece and thereby screws itself into the hole. Upon cessation of feed by the driving machine with retraction of the drving machine, relative axial movement results between the tap holding spindle and the driver members such that the forward drive member becomes disengaged from the tap spindle which at this point is held relatively stationary due to the fact that the tap has become fastened to the workpiece. Upon further retract ! ve movement by the tapping machine and further relative movement. the reverse drive member pecomes engaged w) th the tap holding spindle. causing reverse rotation thereof and thereDy unscrewing the tap from the hoie In this manner. self-reversing by the tapping attachment Itseif as opposea to reversing Dy the dnmng machine is acccmDnshed With the advent of powerful Computer Numeric Control (CNC) machining centers, self-reversing has become of greater and greater importance in that it causes reversing to occur in the tapping attachment, as opposed to requiring the driving machine to reverse its direction of rotation.

Self-reversing tapping attachments as exemplified in the above- cited patents among others, have particular parts which due to the very nature of self-reversing suffer greater wear than other parts. These parts include elements of the drivers and in particular drive splines and related parts.

Replacement of wom parts in existing tapping attachments produces delays and down time. Disassembly of existing tapping attachments in itself requires appreciable time and some degree of skill.

Major wear occurs in particular parts which engage to provide forward and reverse rotation of the tap holding spindle. These parts are in the form of splines or dogs. In existing tapping attachments, these splines or dogs are milled/machined in the part when the part is fabricated. As a result, the severe wear which the splines receive and undergo causes premature discarding of entire parts of which the splines are elements.

Ready disassembleability of tapping attachments has become increasingly desirable in view of the necessity for replacement of parts resulting from the extremely high velocity--and high torques-of modern machining.

Existing devices such as those described and claimed in the above-referred prior art patents, provide substantial disassembleability. Further accessibility to the interior of the tapping attachment and disassembleability are, however, desirable. In the provisional patent application referred to hereinabove, drive elements in the form of removable drive splines, are disclosed.

In particular applications it is deemed advantageous to provide additional forms of removable drive elements.

SUMMARY OF THE INVENTION A seif-reverslng tapping attachment comorises: tap holding spindle means : forward drive means and reverse drive means for engaging with the tap holding spindle means to impart forward and reverse rotation respectively, thereto ; gear means for transmitting drive to the forward and reverse drive means, driver subassemolies including removable drive elements. elements being contained in a aisassemoieaoie housing, a removaoie drive eiement compnsing a drive spline disposed on a connector nestable in a receptacles defined in drivers. In another embodiment a plurality of drive splines are mounted on a holder nestable in receptacle defined in drivers.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a tapping attachment in accordance with the invention; Fig. 2 is a sectional view through the line 2-2 of Fig. 1; Fig. 3 is a partial sectional view of a drive component receptacle in accordance with the invention, through line 3-3 of Fig. 2; Fig. 4 is an enlarged view of a portion of Fig. 3 above; Fig. 5 is a top view of a removable drive element in accordance with the invention, in the receptacle of Fig. 3 ; Fig. 6 is a top view of a removable drive component in accordance with the invention; Fig. 7 is a side view of a removable drive component in accordance with the invention; Fig. 8 is a sectionat view through the line 8-8 of a removable drive component in accordance with the invention; Fig. 9 is a perspective view of a portion of a removable drive component in accordance with the invention; Fig. 10 is a perspective view of a receptacle for accommodating a removable drive component in accordance with the invention ; Fig. 11 is a top view of an alternative embodiment of a drive component holder in accordance with the invention : Fig. 12 is a top view of an alternauve removable drive component in accordance with the invention: and Fig. 13 is a perspective view of the drive component receptacle depicted in Fig. 11 ; Fig. 14 is a perspective view of the drive component of Fig. 12; Fig. 15 is a top view of the drive component of Fig. 12 in a receptacle of Fig. 11, in accordance with the invention.

DETAILED DESCRIPTION OF A PREFERRED FORM OF THE INVENTION AND PREFERRED METHOD OF PRACTICE.

U. S. Patent No. 5,203,651 and U. S. Patent No. assigned to the assignee of the instant application are hereby incorporated by reference herein. Many of the parts and components, as well as the overall system of a self-reversing tapping attachment are described and depicted in the common subject matter with the instant application. In the description that follows, only brief reference will be made to parts described and depicted in U. S. Patent No.

5,203,651 and U. S. Patent No. 5,628,593 and for purposes of brevity and clarity overlap between the instant application and the aforesaid U. S. Patents will be avoided to the extent possible.

As depicted in Fig. 1, a tapping attachment 10 is coupleable through a shank 12 to a source of rotation drive in the form of a driving machine (not shown). A stem 14 is disposed in and extends from closure 15 positioned adjacent an upper housing eiement 16a of the tapping attachment 10 and is connectable in conventional fashion to the driving machine to provide restraint against rotation of the housing element 16a of tapping attachment 10 when connected to the driving machine. The driving machine causes rotation of shank 12 and the driving parts within housing 16. Upper housing element 16a, which is restrained by stem 14, is secured to a lower housing element 16b through a perimetral region of a gear carrier 46 described in further detail hereinbelow. Housing elements 16a, 16b define a central bore 17 for receiving a drive spindle memoer 18.

Referring now also to Fig. 2, inclusive, a mount 20 having an insert 22, defines a central bore 24. Nut 28 is carried on a tap spindle member 30 for the purpose of holding a tap (not shown). Spindle memoer 30 is assemble with spring members 32 retained by a cap 34. A gear 40 composes an upper gear member 42 and a lower gear memoer 44 A gear carrier 46 is secured between housing element 16a and housing element 16b. Securement is by bolts (not shown) disposed in bolt holes (not shown) defined in gear carrier 46. A plurality of planet gears 48 (depicted as three in number) are mounted in planet gear carrier 46. Planet gears 48 are engageable with gear 40.

A forward drive member of generally annutar configuration defines a central bore 52. Forward drive member 50 is engageable with upper gear 42. and carries fittings 56. Along. its inner periphery drive member 50 defines at least one drive component holder in the form of at least one drive spline member receptacle 59 (shown as three in number) for receiving removable drive components in the form of removable spline members 53. Each spline member 53 is configured to fit matingly into receptacle 59. Spline member 53 includes a connector 77 on which a spline 54 is disposed, connector 77 being configured to fit into receptacle 59.

Spline 54 may be of any desired configuration. Examples of desirable configurations are disclosed in U. S. Patent Nos. and 5,209,616 assigned to the assignee of the present application. In the particular embodiment described herein spline 54 is generally pentahedral including an upper surface 70 and lateral segments 72,74 which are connected, respectively, to ramp members 80,81 on connector 77, lateral segments 72,74 being inciined at acute angles to the path of a drive ball 82 providing a cushioning effect upon driving contact between segments 72,74 and drive ball 82.

Opposite upper surface 70 is a lower surface 73. A contact face 75 defined by edges of segments 70,72,73,74 has a concave curvature. This configuration contributes to cushioning of impact between spline 54 and drive balls 82.

Receptacles 59 are configured to accommodate spline member 53.

Each receptacle 59 includes lateral segments 60.62, an outer segment 64, and a top opening 66, and a lower segment 67. (For purposes of the instant application, the term"outer"means and refers to the direction away from the center of member 52). A screw hole 78 is defined in outer segment 64.

For insertion of spline member 53 into receptacle 59. the connector 77 of spline member 53 is alignea wrth opening 66 of receptacle 59 and is then inserted thereinto. After such insertion. securement is accomplishea by means of engaging a screw 79 with screw hold 78, thereby fastening sptine member 53 to forward drive member 50.

A reverse drive member 84 is engageable with lower gear 44.

Member 84 is identical to forward drive member 50, as are associated parts and components.

Severe stress is imposed upon splines 54 in operation of tapping attachment 10 in connection with which splines 54 perform driving functions.

The removeability of splines 54 affords flexibility and efficiency of operation of tapping attachment 10: upon failure and/or wearing out of splines 54, the worn- out spline members 53 are replaced with new ones whereas in existing devices the entire part 50 requires replacement.

As depicted, splines members 54 are indexe, i. e., symmetrical; thus, wear can be equalized to prolong useful life by periodically rotating spline members 53. Spiines 54 may be fabricated in any desired shape to accommodate particular applications. For example, the radius of curvature may be adjusted to meet varying conditions of use.

Spline members 53 may be fabricated in a variety of ways. They may be machined, sintered or forged. This also provides an advantageous feature with respect to existing devices in that in such devices splines are normally machined as an element of the drive member and due to constraints in manufacturing such fabrication limits flexibility of configuration of the splines.

Because spline members in accordance with the invention are manufactured separately from the parts on which they are carried, spline members 53 may be separately treated (as by heat treatment) for achieving hardness without requiring the entire part to undergo such hardening treatment.

Because such hardness is not necessary for the part carrying splines 54, such hardening of integral splines (requiring the whole part to be heat-treated) is not only unnecessary and uneconomical but also has resulted in compromising the hardness of the splines because hardening the surrounding part to the desirable hardness of splines produces problems of brittleness of the whote part.

A further advantage of removable splines 53 is that they may be fabricated from different material than the part in which they are mounted. Thus, different and superior hardness-providing fabrication techniques can be employed to obtain the desired level of this parameter without mvolving the carrier or any negative side effects such hardening treatment may produce in the carrier.

In addition selected coatings, such as titanium, may be applied to removable splines 53 more feasibly than for integral splines in that the entire part with integral splines would have to be so coated and such a part could be softened by the heat treatment required for coating.

Referring now to Figs. 11-15, inclusive, an alternative embodiment of a removable spline member 90 is depicted therein. A receptacle 92 for spline member 90 is defined in a forward drive member 94. As depicted, receptacle 92 comprises a plurality (shown herein as three) of pockets 96a, 96b, 96c defined in the inner periphery of drive member 94. Pockets 96a, 96b, 96c are of generally in semi-rectangular configuration, having openings 98a, 96b, 98b, 98c at the top of pockets 96a, 96b, 96c, respectively. Screw holes 99a, 99b, 99c are defined in pockets 96a, 96b, 96c, respectively.

Drive spline member 90 comprises a retainer member 100 on which are mounted drive splines 102a, 102b, 103c. The latter are shaped to conform to, and fit into pockets 98a, 98b, 98c. Defined in spline members 102a, 102b, 102c are screw holes 104a, 104b, 104c alignable with screw holes 99a, 99b, 99c defined in drive member 94. Drive member 94 carries fittings 108.

Drive spline member 90 is installed in forward drive member 94 by aligning the individual drive splines 102a, 102b, 102c with pockets 98a, 98b, 98c and then placing drive spline member 90 into fitting engagement with drive member 94. Screws then are employed to fasten drive spline member 90 to drive member 94.

In accordance with the foregoing, improved tapping attachment drive components are provided. The embodiments described and depicted herein are by way of example. The invention is defined by the claims to be submitted subsequently according to law, to be interpreted in light of the specification and drawings.