US3829230A

US3829230A - Tapping attachment adapted for numerical control

Info

Publication number: US3829230A
Application number: US00311296A
Authority: US
Inventors: A Johnson
Original assignee: TOPMATIC CORP
Current assignee: TOPMATIC CORP
Priority date: 1971-03-15
Filing date: 1972-12-01
Publication date: 1974-08-13
Anticipated expiration: 1991-08-13

Abstract

The invention is a tapping attachment of a type having free axial float and automatic depth control. The attachment embodies precise adjustment means for precisely adjusting or controlling the point at which the depth control will release. The depth control includes releasable engagement members movable relatively axially to release. The control means comprises an adjustable limiting member which precisely controls or limits the amount of inward positioning of the driven part of the engagable means relative to the driving part and thereby sets the amount of outward relative movement of the driven part which will cause release. The adjustable limiting means embodies a spring to insure against damage occurring to the attachment in the event the tapping element should encounter the absence of a hole to be tapped.

Description

llit States ,lohnson atent 1191 [54] TAPPHNG ATTACHMENT APTED TOR 3,397,588 8/1968 Johnson 408/132 x NUMERICAL CONTROL [75] Inventor: Allan S. Johnson, Newport Beach, Primary Examiner c lil Weidenfeld Calif Attorney, Agent, or Fzrmi-lerz1g & Walsh [73] Assignee: 'llopmatic Corporation, Costa Mesa,

CaIifi [57] ABSTRACT [22] Filed: Dec. 1, 1972 The invention is a tapping attachment of a type having free axial float and automatic depth control. The at- [21] Appl' 311L296 tachment embodies precise adjustment means for pre- Relateol US. Application Data cisely adjusting or controlling the point at which the [63] continuatiomimpan of Set No. 124,020' March 157 depth control will release. The depth control includes 1971, Pat. No. 3,791,756, and a continuation-impart releasable engagement members movable relatlvely of Ser. No. 26,894, April 4, 1970, Pat, No axially to release. The control means comprises an ad- 3,717,892. justable limiting member which precisely controls or limits the amount of inward positioning of the driven [52] US. Cl. 408/14, 408/142, 10/89 F, part of the engagable means relative to the driving 10/141 H part and thereby sets the amount of outward relative [51] int. Cl. 823g 3/00 movement of the driven part which will cause release. [58] Field of Search 408/14, 139, 142, 124, The adjustable limiting means embodies a spring to 408/132; 10/89 H, 89 F, 141 H, 129 R; 192/141 insure against damage occurring to the attachment in the event the tapping element should encounter the [56] References Cited absence of a hole to be tapped.

UNITED STATES PATENTS 7 Claims, 8 Drawing Figures 1,915,542 6/1933 Lundin et a1. 408/124 g 45 46 X -20 30 u. 7. 22 a! 5:; W g

ee 3 9d 4 s p 5 1 T *r' 92 52 w -84 5 1 24 v0 A74 3 vag /34 E s 7% 4 lllll 34 /00 g :5 70 m f 4 60 L. -1

a .v J 1 1 7,1- A .L F 1 l l l V v T T D FOR This application is a continuation-in-part of U.S. Pat. application Ser. No. 124,020 filed on Mar. 15, 1971 now U.S. Pat. No. 3,791,756, and is a continuation-inpart of Ser. No. 26,894 filed on Apr. 4, 1970 now U.S. Pat. No. 3,717,892.

SUMMARY OF THE INVENTION The invention is a tapping attachment of a type having automatic depth control. The improvement comprises improved adjustable means for adjustably controlling accurately a point or position at which the depth control means will release. The nature of the improvement is explained more fully hereinafter.

BACKGROUND OF THE INVENTION U.S. Pat. Nos. 3,041,893 and 3,397,588 are repre sentative of tapping attachments of types in which the invention of this application might be embodied. The prior applications referred to above show attachments having depth control in them, as well as means for adjusting or controlling the release point of the depth control. Reference is also made to U.S. Pat. Nos. 3,002,206 and 3,472,347.

The depth control means as known, typically comprises a driving part in the form of a skirt having axial notches in which radial pins in the driven part engage. In operation, the attachment is being advanced by the machine while the spindle is rotating to perform the tapping operation. At a predetermined position under automatic or computer control, the advance of the attachment will stop; whereas, the rotation continues with tapping continuing until the depth control releases. It is desired in this type of control to be able to predetermine exactly a position, that is, the depth at which release will occur to insure accurate tapping. The depth control adjustment is in the form of an adjustable means which establishes the amount of relative inward movement or positioning of the driven part with respect to the driving part, that is, the inward movement of the radial pins relative to the notches in the skirt. This necessarily adjusts or controls the amount of outward movement which will cause release and discontinuance of tapping.

The improvements of the herein invention reside in forms of depth control adjustments embodying a spring which biases the adjustment means. The spring is so arranged that the limit position imposed on the inward movement of the driven member is not positive, but rather further inward movement can occur upon compression of the spring. Thus, the improvement insures against breakage or damage which might otherwise occur in the event that the tapping bit failed to encounter a hole to be tapped, thus forcing unexpected inward movement of the driven part. The primary object of the invention is to provide this particular feature, that is, that the depth control adjustment is by way of a spring means to greater inward movement against the spring bias to avoid the type of damage referred to.

Further objects reside in particular improved constructions embodying the feature as described. The objective is realized in one form by way of a threaded collar positioned to position the driving and driven parts relatively, but to allow inward movement of the floating spindle assembly against the spring biasing means.

A further object is to provide a further improved construction wherein the adjusting means takes the form of a threaded collar or bushing having an associated sliding sleeve with the biasing spring positioned between the sleeve and the bushing itself.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects and additional advantages of the invention will become apparent from the following detailed description and annexed drawings, wherein:

FIG. I is a view of preferred form of the attachment mounted in a machine;

FIG. 2 is a cross sectional view of the attachment of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along the line 4--4 of FIG. 2;

FIG. 5 is a view of another form of the attachment mounted in a machine;

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 5;

FIG. 7 is a sectional view taken along the line 77 of FIG. 6; and

FIG. 8 is a sectional view taken along the line 8-8 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, 10 designates a machine tool with which the attachment may be used. The tool may be of a type operated under automatic control such as computer control. The machine may be of a type having a head carrying multiple spindles, for example twenty spindles all individually driven. This type of machine is able to drill or tap multiple holes in a work piece at the same time. It may be desirable to tap holes of different depth. Numeral l1 designates generally the attachment having a shank or stem part 14 carried by head 10. Numeral I3 designates a receptacle: which may be of a type adapted to receive a quick change chuck assembly.

In FIG. 2, numeral 14 designates a stem which is within head 10 and is driven and forms a receptacle to receive attachment 11. The attachment has a cylindrical shank member 20 having bore 21, the upper part of which is received in bore 22 in cylindrical stem 12. Shank member 20 has a milled tapered flat 24, and it is held in position by a set screw 26 which engages against the flat and by which the amount of insertion is fixed.

Numeral 30 designates a woodruff key which is fitted into an opening 31 in the opposite side of shank member 20 and which moves in an axial groove 32 on the inside of tubular stem 14.

The lower part of member 20 is threaded as shown. Numeral 34 designates a threaded collar which fits onto the threaded part of the member which engages against the lower end of the tubular stem 14. It may be set in position by way of set screw 36 engaging insert 37.

A torque release clutch can be built into the shank 20 of the attachment; or alternatively, a torque release clutch may be built into a quick change chuck assembly carried by the receptacle I3. Such alternatives are illustrated in the prior applications referred to.

At the upper end of member there is an end plug or closure member 46 carrying a stem 48 as shown. This stem extends down into the tubular spindle 52. The spindle has a longitudinal bore 54. In the upper end of this bore is a bushing 56 through which stem 48 extends. At the lower end of spindle 52, it carries receptacle 13 adapted to rceive a quick change chuck assembly, not shown. This assembly is like that of the previous application referred to, Ser. No. 26,894 now US. Pat. No. 3,717,892. At the end of bore 54, there is a counterbore 62 which receives bearing 64 having a lug 66. Attached to lug 66 is axial float spring 70 at the other end of which is a hook 72 connected to lug 74 at the end of stem 48.

The attachment embodies a depth control adjustment. Numeral 80 designates a cylindrical member or sleeve having an extending skirt part with two axial slots in it as designated at 82 and 84. It is biased by spring 86 between it and plug 46.

Numerals

90 and 92 designate radial pins carried in

bores

94 and 96 in member 20. These pins extend into

slots

82 and 84. Sleeve member 80 of the depth control adjustment is positioned between spindle 52 and member 20.

Numerals

100 and 102 designate radial pins fitting in

radial bores

104 and 106 in spindle member 52, as shown. Spindle member 52 can move axially with respect to sleeve member 80 in

slots

82 and 84 as will be described.

Numeral 100 designates a bushing fitting between spindle member 52 and member 20, as shown and held in position by

set screws

112 and 114 which extend through member 20 and engage in an annular recess 116 in bushing 110.

Bushing 100 is fixed in position. Accurate means are provided for setting or adjusting the depth control so as to exactly predetermine the depth at which the depth control will rlease. The lower end of spindle 52 is threaded as designated at 120. Threaded onto the stem is a collar 122 having a radial threaded bore 124 receiving a set screw 126. Positioned between collar 122 and the lower end of bushing 110 is a biasing spring 130 which surrounds spindle 52. Collar 122 can be adjusted from a position against receptacle 13 upwardly on threaded part 120 of spindle 52 against biasing spring 130. As may be observed, when collar 122 is adjusted upwardly on spindle 52, it will tend to compress spring 130 to pull spindle 52 downwardly, the radial pins 100 and 102 moving downwardly in

axial slots

82 and 84. Thus, in this manner, it is possible to accurately set or adjust the amount of relative downward movement of spindle 52 which will cause the radial pins to release from

axial slots

82 and 84, that is, the depth at which release will occur.

Briefly summarizing the operation, it is as follows. The attachment is operated by the machine to rotate it and to advance it axially while the tapping element carried by the attachment is tapping into a drilled hole. By automatic control, at a predetermined position of ad vance, the machine will stop the advance of the attachment while it continues to rotate the spindle. While continuing to rotate, the tapping element will continue to tap into the hole with continued axial advance of spindle 52 with

radial pins

100 and 102 moving in

axial slots

82 and 84 in member 80. Depending upon the adjustment, at a predetermined depth, the radial pins will release from the slots. At this point, member 80 moves upwardly against biasing spring 86 to effect release without chattering which is allowed by reason of bevelled surfaces as shown at 134 at one side of

axial slots

82 and 84.

It will be observed that spring provides safety, preventing possible breakage under automatic control. In the event for example, that the tapping bit encountered a surface where no hole had been drilled so that the spindle was unable to advance, breakage would be prevented since the drilling element and spindle can be forced inwardly with respect to the attachment against the force of spring 130. The spring and length of the axial slots in skirt 80 allow considerable relief for relative movement inwardly.

FIGS. 5, 6, 7, and 8 show a modified form of attachment with a different form of means providing the depth control adjustment. Parts which are the same as the previous embodiment are identified by the same reference numerals and the previous description is applicable. Parts which are similar but not identical are identified by the same numerals primed, the previous description being applicable except as explained hereinafter.

In this form of the invention at upper part of member 20, there is an end closure member 131 which has an extending skirt part 132 in which there are provided three spaced

axial slots

134, 136, and 138 which will be referred to again presently. Above skirt 132 in member 131, there is a bore 142 and a counterbore 144. In bore 142 is received the end of a tubular member 148. In the end of this tubular member, there is a plug having an end flange 152 and a lug 154 into which is hooked the end of axial float spring 70. Spindle 52' has a bore 54. In the upper end of this bore is a bushing 56. Tubular member 148 extends down into spindle 52', through bushing 56.

The depth control adjustment includes member 160, the upper part of which is designated at 162. This member has a bore 164 and an extending skirt 166. The extending skirt is of larger diameter. Upper part 162 has a bore 164. In this bore is bushing through which tubular member 148 extends. Numeral 172 designates a biasing spring received in bore 144 in member 131. The other end bears against depth control member 160. In upper end 162, there are three

radial bores

176, 178, and which receive

radial pins

182, 184, and 186 in the

axial slots

134, 136, and 138 in skirt 132 of member 131. Skirt 160 is of a size to fit into bore 21 of member 20. Skirt 166 fits around the upper end of spindle member 52'. Formed in skirt 166 are three equally spaced

axial slots

170, 172, and 174. At the upper end of spindle member 52 there are three, equally spaced radial bores 180, 182, and 184 which receive

radial pins

190, 192, and 194 which extend into

vertical slots

170, 172, and 174 in skirt 166 of member 160. The operation of the depth control will be described presently.

In the present form of the invention, the depth control adjustment comprises a bushing 200 which is internally threaded as shown and which is threaded onto member 20' as shown. In the side wall of bushing 200 is a threaded bore 202 which receives set screw 204. Bushing 200 has a part 208 of larger diameter as shown. This part has a bore 210. The lower end of the bushing has a bore 212. Slidably fitting on part 208 of larger diameter of bushing 202 is a sleeve member 220 which is cup shaped having an end 222 with bore 224 through which spindle 52 extends. Within this sleeve is a biasing spring 230 which surrounds end 232 of bushing 2M and bears against the shoulder formed by part 208 of larger diameter of bushing 200, the other end of the spring bearing against the end part 222 of sleeve 220. Movement of sleeve 220 outwardly with respect to bushing 2110 is limited by lockwire 236 received within a groove in the end of sleeve 220 to engage the shoulder formed by part 2118 of larger diameter of bushing 200.

As will be observed, end 222 of sleeve 220 bears against receptacle 13. Spring 230 is under compression.

The operation of this embodiment is similar to the previous embodiment. As may be observed, the adjustment of the bushing or collar member 220 downwardly on shank 211' will cause receptacle 13 and spindle 52' to move downwardly with the radial pins 191], 192, and 194 moving downwardly in the

axial slots

170, 172, and 174 in member 160. In other words, by adjustment of collar or bushing 200, the depth control adjustment is made, that is, the depth at which release will occur is precisely adjusted.

The operation is like that described above. The attachment will be advanced by the machine to a predetermined position with rotation of the spindle continuing. The spindle will continue to tap into the hole, advancing axially until radial pins 190,192, and 194 disengage from

axial slots

170, 172, and 174 to bring about release. This occurs at the predetermined setting of the depth control adjustment. Release is facilitated by the slanting or bevelled surfaces as shown at 240 on one side of slot 170. When release occurs, member 162 moves upwardly against spring 172.

Safety is provided as in the previous embodiment in that should the drilling element encounter a surface not having a drilled hole, receptacle 13 and spindle 52 will have the freedom to move inwardly axially against the force of spring 230 thus avoiding damage. When bushing 200 is adjusted outwardly, sleeve 220 moves outwardly and pins 190, 192, and 194 adjust outwardly in slots 171 172, and 174.

From the foregoing, those skilled in the art will understand the nature and construction of the invention and the manner in which it achieves and realizes all of the objects and advantages as set forth in the foregoing.

The foregoing disclosure is representative of preferred forms of the invention and is to be interpreted in an illustrative rather than a limiting sense, the invention to be accorded the full scope of the claims appended hereto.

What is claimed is:

1. A tapping attachment having a driving part and a driven part, said driven part including a tapping spindle; releasable engagement means between the driving part and the driven part constructed to allow relative axial movement of the driven part carrying the tapping spindle, means normally biasing said parts into engage ment, said releasable engagement means releasing upon an outward axial movement of the driven part, the improvement comprising depth control means for predetermining the magnitude of axial movement of the driven part relative to the driving part to disengage said parts, said adjustment means comprising an adjustable member being adjustably positionable on one of said parts, spring means positioned between the adjustable member and the other of said parts to provide an axial opposed bias between said parts, whereby said adjustable member is adjustably positioned on said one part to preset the desired magnitude of relative axial movement of said parts which will bring about said disengagement.

2. An attachment as in claim 1, wherein said spring means is in the form of a coiled spring encircling the tapping spindle and positioned to be compressed by inward movement of said spindle.

3. A tapping attachment as in claim 2, wherein said adjustable member is carried by said driven member.

4. An attachment as in claim 3, wherein said adjustable member is in the form of a collar threaded onto the spindle.

5. A tapping attachment as in claim 2, wherein said adjustable member is carried by the driving member, the spring being interposed between the adjustable member and the driven member.

6. A tapping attachment as in claim 1, wherein said adjustable member is in the form of a bushing and a sleeve slidably carried by the bushing and engageable with the other part.

7. A tapping attachment as in claim 6, wherein said sleeve has an end flange positioned to seat against the other part.

Claims

1. A tapping attachment having a driving part and a driven part, said driven part including a tapping spindle; releasable engagement means between the driving part and the driven part constructed to allow relative axial movement of the driven part carrying the tapping spindle, means normally biasing said parts into engagement, said releasable engagement means releasing upon an outward axial movement of the driven part, the improvement comprising depth control means for predetermining the magnitude of axial movement of the driven part relative to the driving part to disengage said parts, said adjustment means comprising an adjustable member being adjustably positionable on one of said parts, spring means positioned between the adjustable member and the other of said parts to provide an axial opposed bias between said parts, whereby said adjustable member is adjustably positioned on said one part to preset the desired magnitude of relative axial movement of said parts which will bring about said disengagement.