US3619543A

US3619543A - Positioning fixture to facilitate nozzle drilling by edm

Info

Publication number: US3619543A
Application number: US12218A
Authority: US
Inventors: Edward A Slindee; Geroge E Nicoletti
Original assignee: International Harverster Corp
Current assignee: Navistar International Corp
Priority date: 1970-02-18
Filing date: 1970-02-18
Publication date: 1971-11-09
Anticipated expiration: 1988-11-09

Abstract

Fixture assembly for holding a nozzle blank on which spray openings are to be formed by electric-discharge machining. The fixture assembly comprises a base, a gage block, a pivot block, an adapter block, an adapter, and a headblock. The nozzle blank is held between the adapter and a conical recess in the headblock. The headblock is adjustably positioned so as to accommodate nozzle blanks of different sizes. The adapter is selected so as to give the desired angle between the nozzle blank axis and the axis of the imaginary cone on which the spray openings are to be formed. The gage block determines the angle at which the pivot block is held and thus the angle of the cone of the spray openings.

Description

United States Patent Inventors Appl. No. Filed Patented Assignee POSITIONING FIXTURE T FACILITATE NOZZLE DRILLING BY EDM I Claims, Drawing Figs.

u.s. Cl 219/69 R, 77/64 rm. 0 B23b 1/12, B23b 47/23 Field ol Search 77/64; 219/69 E, 69 M, 69 R [56] References Cited UNITED STATES PATENTS 3,098,148 7/1963 Piot et a1 219/69E 3,350,963 11/1967 Roosa 77/64X Primary Examiner-Ralph F. Staubly Attorney-Floyd B. Harman ABSTRACT: Fixture assembly for holding a nozzle blank on which spray openings are to be formed by electric-discharge machining. The fixture assembly comprises a base. a gage block, a pivot block, an adapter block, an adapter, and a headblock. The nozzle blank is held between the adapter and a conical recess in the headblock. The headblock is adjustably positioned so as to accommodate nozzle blanks of different sizes. The adapter is selected so as to give the desired angle between the nozzle blank axis and the axis of the imaginary cone on which the spray openings are to be formed. The gage block determines the angle at which the pivot block is held and thus the angle of the cone of the spray openings.

POSITIONING FIXTURE TO FACILITATE NOZZLE DRILLING BY EDM This invention relates to a fixture assembly for holding a blank on which machining operations are to be performed. More specifically, the invention relates to a fixture assembly for holding nozzle blanks in which spray openings are to be formed. i

It is known to inject fuel in the form of an atomized spray in an engine, by means of a nozzle and a rapidly reciprocating valve rod in the nozzle tip. The fuel is sprayed into the engine through a plurality of spray openings in a spherical tip end of the nozzle, which openings are distributed about an imaginary cone whose tip coincides with the center of the spherical end and whose axis may coincide with that of the nozzle or be at an angle thereto. Since the spray openings and the spherical end of the nozzle are small, it is desirable to use a wire electrode and form the openings by electric-discharge machining.

The fixture assembly of the present invention holds the nozzle adjacent the wire electrode for the forming of spray openings. The assembly is constructed to handle a plurality of variables with particular means: various sizes of the spherical end of the nozzle, by means of a head block screw head; various cone angles of the cone on which the spray openings are arranged, by means of a gage block; various angles between the cone axis and the nozzle axis, by means of a selected adapter; and various numbers of spray openings, by means of a selected indexing plate.

It can be appreciated from the foregoing that nozzle orifices can be located accurately by setting any combination of angles in the three planes of the indexing plate, gage block, and adapter. Thus, one indexing plate if substituted for another can change machining of a nozzle blank so that each orifice makes an angle to the adjacent orifice which is smaller, for example, thereby increasing the total number of spray openings Thus, one of the gage block steps if substituted for another can change the angular extent or circumferential length of the ring of orifices in a nozzle blank so that the cone at its apex changes to an angle which is smaller, for example. Thus, one adapter if substituted for another adapter can change the axis of the cone or of the ring of nozzle openings in a nozzle blank so that the angle between the cone axis and nozzle axis is changed to a smaller angle, for example, enabling the spray pattern to proceed more nearly longitudinally from the nozzle rather than to one side.

An orifice so set is accurately located and separately set for any angle within three planes relative to the nozzle valve axis. The important feature is that variables in each plane are independent of the other two.

More specifically, a fixture provided according to our invention for vertical drilling of a hole pattern in a nozzle comprises: a rotatable adapter block; a pivot block with rotatable mounting means rotatably supporting the adapter block thereon, and supported by tiltable mounting means to tilt the two blocks from a horizontal position about a fixed, horizontal pivot axis of the pivot block; and nozzle mounting means for supporting a nozzle to be drilled and supported on the adapter block; the rotatable mounting means being effective to rotate the adapter block in the pivot block for positioning the nozzle for drilling a ring of holes a plurality of which are equiangularly spaced apart; the tiltable mounting means comprising the preceding discussed gage block engageable at a point on the pivot block to set the tilt angle by setting the height of the pivot block at that point; the nozzle mounting means comprising the preceding discussed adapter which is revolved by the adapter block, as the adapter block rotates, to carry the nozzle into positions for drilling as described. In particular, the rotary mounting means is the preceding discussed indexing plate selectable from substitutable rotary indexing plates each with a different number of indexed positions to afford precisely that number of holes per ring. The gage block of the tiltable mounting means is a spacer selected from substitutable gage block portions each of a different height determinative of a precise spacing. The adapter is selected from substitutable adapters for holding nozzles each forming a different angle to the adapter block, determinative of the precise angle of the cone pattern axis to the nozzle.

In the drawing:

FIG. 1 is an end view of a nozzle;

FIG. 2 is a longitudinal sectional view of the nozzle taken on the line 2-2 of FIG. I;

FIG. 3 is an elevational view of fixture assembly of the present invention;

FIG. 4 is an end view of one end of the fixture assembly;

FIG. 5 is an end view of the other end of the fixture assembly;

FIG. 6 is a plan view of the fixture assembly:

FIG. 7 is an elevational view of a headblock forming part of the present fixture assembly;

FIG. 8 is an end view of the headblock;

FIG. 9 is an enlarged fragmentary elevational view of the headblock;

FIG. 10 is an enlarged fragmentary sectional view taken on the line 10-10 of FIG. 9;

FIG. 11 is a fragmentary enlarged plan view of the portion of FIG. 6 contained in the enclosure 11 end showing the engagement of the end of a nozzle blank with the headblock;

FIG. 12 is a longitudinal sectional view taken on the line 12--l2 of FIG. 14 and showing a pivot block of the fixture as sembly;

FIG. 13 is an end view of the pivot block taken from one end;

FIG. 14 is an end view of the pivot block taken from the other end;

FIG. 15 is a fragmentary sectional view taken on the line 15-45 of FIG. 14;

FIG. 16 is an elevational view of an adapter block of the fixture assembly;

FIG. 18 is an end view of an adapter of the fixture assembly; FIG. 17 is an end view of the adapter block;

FIG. 19 is a longitudinal sectional view taken on the line l9--19 of FIG. 18; and

FIG. 20 is a fragmentary end view of the adapter taken on the line 20-20 of FIG. 19.

The reference character 30 designates a nozzle or nozzle blank, depending on whether certain spray openings have or have not been formed therein. The fixture assembly of the present invention is adapted to hold the nozzle blank 30 while spray openings are formed therein by electric-discharge machining.

As shown in FIG. 2, the nozzle 30 has a central bore composed of

regions

31 and 32. An elongated plunger or rod 34, which is positioned in the nozzle 30, has a long portion 35 fitting the bore region 31 of the nozzle 30, a long portion 36 lying within the bore region 32 in radially spaced relation thereto, and a conical tip 37 beyond the portion 36 seated on a conical seat 38 in the nozzle 30. Beyond the conical seat 38, the nozzle 30 has a spherical end 39 provided with a plurality of spray openings 40. The nozzle 30 has two longitudinal openings 41 which connect an internal peripheral groove 41a between the

bore regions

31 and 32 with an external annular groove 42 formed in the end of the nozzle remote from the spherical end 39. The groove 41a communicates with a long annular space formed between portion 36 of plunger 34 and bore region 32 of nozzle 30. The nozzle 30 and plunger 34 may be used for injection of liquid fuel into a diesel engine. The liquid fuel is applied to the nozzle 30 by way of the annular groove 42 and the longitudinal passages 41 and causes the plunger 34 to lift because of a spring (not shown) holding conical end 37 on the plunger 34 against the conical seat 38 in the nozzle 30 and a stop (not shown) allowing only very limited movement of the plunger 34 to the left as viewed in FIG. 2. As a result of the opening the fuel passes between the conical end 37 and the seat 38 and is sprayed out the openings 40 into the engine.

For various reasons having to dow with engine operation, the spray openings 40 which may, for example, be from 4 to in number, have their axes arranged on and distributed about an imaginary cone. This imaginary cone has an apex angle represented by G and an axis an angle F with the axis of the nozzle or nozzle blank (FIG. 2). The purpose of the fixture assembly of the present invention is to hold the nozzle blank 30 so that spray openings may be formed therein by electric-discharge machining with various numbers of spray openings, various conical angles G, and various angles F between the axis of the nozzle blank 30 and the spray-cone axis. The fixtures assembly accommodates nozzle blanks 30 with spherical ends 39 of various radii.

As shown in FIGS. 3-6, the fixture assembly comprises a base 43, a gage block 44, a pivot block 45, an adapter block 46, an adapter 47, and a head block 48. The gage block 44, which is slidably positioned on a floor 49 of the base 43, has a plurality of steps 50 of different levels engageable with a roller 51 fixed to the pivot block 45 so that the pivot block 45 will assume various angles with respect to base 43 about a horizontal axis 52. Axis 52 is formed by virtue of the support of the pivot block 45 on and between upstanding ears 53 of the base 43 through pins 54 which enter the pivot block 45 and ears 53 on the horizontal axis 52. The spray-cone angle G, shown in FIG. 2, is determined by the angle of the pivot block 45 about axis 52, as will be explained more fully presently.

As shown in FIG. 11, the head block 48 has a conical recess 55 which engages the spherical end 39 on the nozzle blank 30 when the latter is positioned in the fixture assembly. The head block 48 is adjustably mounted on the pivot block 45, adjustment of the position of the head block 48 adapting it to spherical ends 39 of various radii, as will presently be explained in greater detail. The adapter 47 (FIGS. 3 and 5) is detachable connected with the adapter block 46 so as to be angularly movable therewith about an axis 56 (FIG. 8) and supports the end of the nozzle blank 30 remote from the spherical ends 39 on an axis 57 which forms an angle with the axis 56 which is equal to and determinative of angle F between the nozzle axis and the spray-cone axis, all as will be presently explained in greater detail.

The reference character 58 designates a machining or forming axis, which is vertical, perpendicular to the horizontal axis 52, and lying in the same plane as the axis 56. The

axes

52, 56, and 58 intersect at a common point. A wire electrode (not shown) for forming the spray openings 40 by electricdischarge machining, moves along the machining axis 58 and is held in a slide and wire guide 59 (FIG. 3).

As shown in FIG. 12, the pivot block 45 has at one end spaced ears 60 provided with circular openings 61 for receiving the pivot pins 54 (FIG. 3). The pivot block 45 has, as shown in FIGS. 12 and 14, a circular cylindrical opening 62 formed in a portion 63 of the pivot block 45 extending from the end thereof opposite the cars 60 to a mid region. The opening 62 has as its axis the axis 56 (FIG. 3) and is adapted to receive the adapter block 46 (FIG. 3). A recess 64 is formed in the pivot block 45 in the portion 63 below the opening 62 at the end of the pivot block 45 away from the ears 60 and is adapted to receive and be secured to the cylinder 51 (FIG. 3). As shown in FIGS. 12 and 14, the pivot block 45 has a transverse slot 65 formed in the portion 63 in communication with the opening 62. A threaded opening 66 is formed across one end of the slot 65 in an upper corner of the portion 63. As shown in FIGS. I4 and I5, a longitudinal opening 67 extends through the portion 63 of the pivot block 45 at an upper comer thereof opposite the threaded opening 66, a slot 68 is formed in the top of the opening 67. One end of the opening 67 is closed by a disc 69. The purpose of the transverse slot 65. The threaded opening 66, and the opening 67 will appear presently.

As shown in FIGS. 12 and 13, the pivot block 45 is provided with two longitudinal openings 70 extending from the end of the pivot block 45 where the ears 60 are located to an intermediate region of the pivot block. The openings 70 are at opposite sides of the pivot block 45near the base thereof. Inward of the openings 70, there are two longitudinal openings 71,

which are smaller in diameter than the openings 70, but like the openings 70 extend from the same end of the pivot block 45 to an intermediate region thereof. An opening 72 is provided near the inner blind end. The opening 72 extends vertically from the base of the pivot block 45 across the opening 71 to the opening 62. The purpose of the

openings

70, 71, and 72 will appear presently.

As shown in FIGS. 7 to 11, the conical recess 55 is fonned in the headblock 48 near and at its top. The pivot block has a narrow transverse horizontal surface 73 at the top, which is defined by an intermediate vertical surface 74 and a sloping surface 75. The conical recess 55 is formed so as to extend from the vertical surface 74 and to intersect the top horizontal surface 73 so as to form therein an opening 76, through which the wire electrode (not shown) has access to the spherical end 39 of the nozzle blank 30. A cylindrical bore 760 extends from the conical recess 55 into the sloping surface 75 of the head block 48. The bore 76a was originally formed between the

surface

74 and 75 before the conical recess 55 and serves as an aid in forming the same.

The surface 75 on the headblock 48 is made to slope downwardly and to the right as viewed in FIGS. 3, 8, and 10 from the narrow top surface 73, so that there will be no interference between the head block 48 and the slide and wire guide 59 when the head block 48 and the pivot block 45 are swung counterclockwise as viewed in FIG. 3 to an appreciable extent and the guide 59 along with the wire electrode is moved downwards.

The head block 48 has two large openings 77 and two small openings 78 which are, respectively, of the same diameter as the

openings

70 and 71 in the pivot block 45 (FIGS. 12 and 13). When the pivot block 45 and head block 48 are in the assembled position of FIGS. 3, 5, and 6, the openings 77 and the openings 78, respectively, are aligned with the

openings

70 and 71. In the assembled position, guide pins 79 (FIGS. 5 and I 6) in the openings 70 (FIGS. 12 and 13) in the pivot block 45 fit the openings 77 (FIG. 7) in the head block 48 for mounting the head block 48 on the pivot block 45. The head The head block 48 is held against the pivot block 45 by a pair of springs 80 (FIG. 6) which are positioned in openings 71 (FIG. 12) in pivot block 45 and openings 78 (FIG. 7) in head block 48 and are connected to the pivot block 45 and the head block 48 by pins 81 (FIG. 6) which engage the ends of the springs 80 (FIG 6) and are lodged in vertical openings 72 (FIG. I2) in pivot block 45 and vertical openings 82 (FIG. 7) extending in the headblock 48 from the base thereof across the openings 78.

As shown in FIGS. 3 and 5, an adjusting screw 83 with a large disklike head 84 extends through the head block 48 in threaded engagement therewith and abuts the end of the pivot block 45. The screw head 84 has markings 85 representative of radii of the spherical end 39 on the nozzle blank 30 (FIG. 2), which markings are to be used in conjunction with a marking 86 on the head block 48. The adjusting screw 84 may be held against rotation by a set screw 87 which engages a threaded opening in the head 84 and abuts the headblock 48.

As shown in FIG. 16 and 17, the adapter block 46 has a circular cylindrical exterior 88 which is adapted to fit opening 62 in the pivot block (FIG. 12). The adapter block 46 has a peripheral groove 89 which is to cooperate with the transverse slot 65 FIGS. 12 and 14) in the pivot block 45 and with a narrow bar 90 FIGS. 3 and 6) positioned in the slot 65 and the peripheral groove 89, in holding the adapter block 46 against movement with respect to the pivot block 45 along the axis 56 while allowing angular movement of the adapter block about the axis 56. The adapter block 46 is released from the pivot block 45 when the bar 90 is swung out of the peripheral groove 89 in the adapter block 46 (FIG. 16) about a screw 91 FIG. 6) engaging the opening 66 in the pivot block 45 (FIGS. 12 and 14). The narrow bar 90 is manipulated by a screw 92 (FIGS. 3 and 6) which protrudes from the narrow bar at the ends thereof remote from the screw 91.

As shown in FIG. 16, the adapter block 46 has a short axial extension 93 and a threaded axial opening 94 formed thereat which are employed to mount an index plate 95 (FIGS. 3, 4, and 6) on the end of the adapter block 46 beyond the pivot block 45 by means of a screw 96. As shown in FIGS. 3 and 4, the index plate 95 is connected to the adapter block 46 for rotation therewith by a pin 97 extending through the index plate into the adapter block. The index plate 95 extends radially outwardly of the adapter block 46 so as to overlap the portion 63 thereof in which opening 62 is formed and has at this radially outward location a plurality of peripherally distributed equally spaced openings 98 corresponding in number to the spray openings 40 (FIG. 2) to be formed in the nozzle blank 30. The index plate 95 and the adapter block 46 are fixed at various angular positions of the adapter block with respect to the pivot block 45 about the axis 56 by means of the openings 98 and a reduced projection 99 receivable in the openings, which projection, as shown in FIG. 6, is formed on one end of a retractable member 100 slidably positioned in the opening 67 (FIG. in the adapter block 46. The member 100 is urged toward the index plate 95 by a spring 101 (FIG. 6) one end of which acts against the end of a long recess formed from the end of the member 100 opposite the projection 99 and the disc 69 (FIG. 15) fixed in the end of the opening 67. The retraction of the projection 99 from the openings 98 in the index plate 95 is effected by manipulation of a screw I02 (FIGS. 4 and 6) attached to the retractable member 100 and projecting therefrom through the opening 68 (FIG. 15) in the pivot block 45 to the exterior thereof.

As shown in FIGS. 16 and 17, the adapter block 46 has at the end remote from the extension 93 by which the index plate 95 is attached, a relatively wide transverse groove 103, which is adapted to receive the adapter 47 (FIGS. 18 and 19). The adapter block 46 has an axial opening 104 at the base of the groove 103, which opening cooperates with the opening 105 (FIG. 19) in the adapter 47 and with a dowel 106 (FIG. 3) received in the

openings

103 and 104 to position the adapter 47 in the groove 103 in the adapter block 46. A screw 107 (FIG. 3) extending through an opening 108 (FIG. 19) in the adapter 47 into threaded engagement with an opening 109 (FIGS. 16 and 17) in the adapter block 46 secures the adapter 47 to the adapter block 46, as shown in FIGS. 3 and 6.

As shown in FIGS. 18 and 19, the adapter 47 has an end portion 110 which is thicker than the balance of the adapter and has an inclined surface 111 which is perpendicular to the axis 57 (FIG. 3) along which the nozzle blank 30 extends when in the present fixture assembly. A relatively large shallow circular recess 112 is formed in the surface 111. A relatively small deep circular recess 113 is formed in the base of the recess 112. The axes of the

recesses

112 and 113 are coincident with the axis 57, and the bases at these recesses are perpendicular to axis 57 and parallel to surface 111. As shown in FIG. 20, two recesses 114 are formed in the base of the recess I12 radially outwardly of the recess 113, with an angular spacing from one another about the axis 57, of some substantial angle other than 180, for example 135. The spacing of the openings 114 in the adapter 47 is the same as that of recesses 115 (FIGS. 1 and 2) formed in the nozzle blank 30 at the peripheral groove 32. Dowels 116 (FIG. 3) are received in the

recesses

114 and 115 of the adapter 47 and the nozzle blank 30 for properly orienting the nozzle blank about the axis 57.

As shown in FIG. 3, a spring 117 acts between the adapter 47 and the end of the nozzle blank 30 away from the spherical end 39 thereof to urge the spherical end 39 against the conical recess 55 in the head block 48 The end of the nozzle blank 30 is received in the recess 112 (FIG. 19) in adapter 47, and the spring 117, in recess 113 (FIG. 19) therein.

SIMPLEST CONE APEX ANGLE-4N GENERAL all drilling is perpendicular to and intersects the vertical forming axis 58.

SIMPLEST CONE APEX ANGLE-WITH SIMPLEST CONE AXIS ANGLE The simplest cone axis angle imparted to a hole pattern in the nozzle is a 0 angle, i.e., the cone axis and nozzle axis coincide.

The nozzle and the pivot block are horizontal, and their axes are coincident and their axes are perpendicular to and intersect the vertical forming axis 58.

Each hole in the nozzle is therefore at right angles to the nozzle axis. Although FIG. 2 does not show each hole at right angles to the nozzle axis, the result can be appreciated by visualizing the cone apex angle G increased to 180 and visualizing the cone axis angle F decreased to 0.

FIXTURE ADJUSTMENT When the fixture assembly of the present invention is to be used for forming spray openings 40 in the nozzle blank 30, the first step is to adjust the head block 48 in accordance with the radius of the spherical end 39 on the nozzle blank 30 in which the openings 40 are to be formed. The apex of the imaginary conical surface on which the spray openings 40 lie should coincide with the center of curvature of the spherical end 39. For this to occur, the center of curvature should be on the machining axis 58, along which the wire electrode moves. The headblock 48 is adjusted by the screw 83, which is turned to bring the particular marking on screw head 84 corresponding to the desired radius of the spherical end 39 opposite the marking 86 on the headblock 48, as shown in FIG. 5. In the position of FIG. 5, the screw 83 is set for a radius of 1.2 mm., the minimum radius shown by markings 85. Correspondingly, in the position of FIG. 3, head block 48 abuts pivot block 45, because the end of screw 83 does not protrude from the head block 48. Thus, headblock 48 is as far to the left as possible as viewed in FIG. 3, with respect to pivot block 45, and conical recess 55 is as far to the left as possible as viewed in FIG. 11, with respect to machining axis 58, and so can engage spherical end 39 of minimum radius on nozzle blank 30 so as to place the center of curvature of the spherical end on the machining axis 58.

As the adjusting screw 83 is adjusted from the position of FIGS. 3 and 5, the end of the screw protrudes against the adjacent end of the pivot block 45, and so the headblock 48 moves rightwards as viewed in FIG. 3, with respect to the pivot block 45. As the headblock 48 moves to the right, the conical recess 55 also moves rightwards as viewed in FIG. 11, with respect to the machining axis 58 and becomes suited to engaging a spherical end 39 of greater radius for placing the center of curvature thereof on the machining axis 58 for proper location of the spray openings 40. The farther the end of screw 83 protrudes from headblock 48, the greater the spacing of headblock 48 from pivot block 45, the farther to the right as viewed in FIG. 11 the conical recess 5 with reference to machining axis 58, and the greater the radius of spherical end 39 to be accommodated in conical recess 55. Once the adjusting screw 83 is properly positioned to give the correct location of the conical recess 55, the adjusting screw is fixed by the set screw 87.

Now, the narrow bar is swung about the screw 91 out of the circumferential groove 89 in the adapter block 46, whereby the adapter block and the attached adapter 47 can be shifted to the left to facilitate insertion of the nozzle blank 30 in the fixture assembly. It is presumed that the correct adapter 47 has been chosen to give the desired angle F (FIG. 2) between nozzle-blank axis and spray-cone axis, which is equal to the angle between the axes 56 and 57 (FIG. 3). With the placing of the nozzle blank 30 on the adapter 47, the dowels 116 will have been received in the recesses in the blank 30 and the adapter 4'7 and the spring 117 will have been applied between the end of the nozzle blank 30 and the adapter 47.

Now the adapter block 46 is moved to the right as viewed in FIG. 3 so that the peripheral groove 89 in the adapter block 46 registers with the slot 65 in the pivot block 45, whereupon the narrow bar 90 is swung downwards into engagement with the peripheral groove 89. It is presumed that the index plate 95 with the correct number of opening 98 therein for the desired number of spray openings 40 to be formed in the nozzle blank 30 has been attached to the adapter block 46 by the screw 96 and the pin 97. The gage block 44 is suitably positioned with respect to the roller 51 on the pivot block 45 so that the roller rests at step 50 on the gage block 44 for the desired spraycone angle G (FIG. 2).

I80 CONE APEX ANGI..E-SPECIFIC EXAMPLE As positioned in FIG. 3, the gage block 44 holds the pivot block 45 at the angle required for a spray-cone apex angle G of 180 to be formed. With the spray-cone angle of 180, the openings 40 to be formed will, in a sense, not be on a cone, but on a plane.

DRILLING Now, the wire electrode is brought down along the forming axis 58 to form the first of the openings 40 in the spherical end 39 of the nozzle blank 30. After the first opening is formed and the wire electrode is returned upwardly, the reduced projection 99 is retracted from the associated opening 98 in the index plate 95 by manipulation of the screw 102 along the slot 68 in the pivot block 45. The index plate 95, adapter block 46, and adapter 47 are angularly shifted to bring the next opening 98 to the projection 99, whereupon the screw 102 is released and the spring 101 acts against the retractable member 100 to engage the projection 99 with the groove opening 98. The shifting of the projection 99 (FIG. 6) from the first opening 98 to the next opening 98 produces a needed shifting of the nozzle blank 30 about the axis 56 to position the spherical end 39 on the nozzle blank so that the wire electrode descending again along the forming axis 58 will form a second spray opening 40 at the desired location appropriately displaced from the first opening 40. The procedure is repeated until an entire set of spray openings 40 is formed.

I70 CONE APEX ANGLE-SPECIFIC EXAMPLE If on the new nozzle 30 openings are to be formed on a smaller cone angle G (FIG. 2), the gage block 44 is moved to the right as viewed in FIG. 3, resulting in counterclockwise swinging of pivot block 45 due to engagement of the cylinder 51 with a lower step 50 on the gage block 44. This means an increase in the angle between the machining axis 58 and the axis 56 of the pivot block 45. When in the position of FIG. 3, the cone angle is 180, the angle between the

axes

56 and 58 is 90. When the cylinder 51 is shifted to 170 of the gage block 44, the angle between the

axes

56 and 58 is increased by The cone angle G is equal to twice the difference between 180 and the angle between the

axes

56 and 58. The angle between the nozzle blank axis and the spray-cone axis is the angle between the

axes

56 and 57 of the pivot block 45 and the nozzle blank 30 when in the fixture assembly.

CONE AXIS ANGLE-SPECIFIC EXAMPLE The angle of the axis 57 with respect to the axis 56 is deter mined by the appropriate selection of the adapter 47. In FIG. 3, the adapter 47 shown provides an angle of 15 between the

axes

56 and 57.

It is contemplated that other adapters 47 providing angles of 0 and may also be used. The index plate 95 shown in FIG. 4 has eight openings 98, enabling eight spray openings 40 to be formed in the nozzle blank 30. If other members of spray openings are to be formed, other index plates 95 with the numbers of openings desired are attached as required to the adapter block 46.

- The purpose of the dowels 116 (FIG. 3), the recesses 114 in the adapter 47 (FIG. 20), and the recesses 115 in the nozzle blank 30 (FIGS. 1 and 2) is not only to hold the nozzle blank 30 against turning in the adapter 47, but also to orient the spray openings 40 with respect to the recesses 114 in the nozzle 30 with respect to the axis thereof. With the spray openings 40 and the recesses 115 oriented with respect to one another, the spray openings may be individually oriented about the nozzle axis with respect to an engine (not shown) in which the nozzle 30 is applied through dowels (not shown) fitting in the recesses 115 in the nozzle and in recesses (not shown) in the engine.

What is claimed is:

l. A fixture assembly for holding a nozzle blank having a spherical end for the forming therein of a plurality of spray orifices lying on and distributed about an imaginary cone having an axis hereinafter called the spray-cone axis and an apex angle hereinafter called the spray-cone angle, the orifices being formed by a tool moving along a line hereinafter called the forming axis, said fixture assembly comprising a pivot block (45) mounted for angular movement about a first axis (52) perpendicular to the forming axis and containing a second axis (56) angularly movable with the pivot block in a plane perpendicular to the first axis and containing the forming axis, a particular angular position of the pivot block about the-said first axis producing a particular angle between said second axis and the forming axis determinative of a particular spray-cone angle, means for mounting the end of the nozzle blank away from its spherical end on the pivot block to give the axis (57) of the nozzle blank an angle with said second axis, determinative of the angle between the spray-cone axis and said axis of the nozzle blank, said mounting means enabling the nozzle blank to be moved about said second axis with respect to the pivot block for the formation of the various spray orifices of a given plurality thereof lying on the same spray cone, and a headblock (48) having a conical recess engageable with the spherical end of the nozzle blank and being mounted on the pivot block, the conical recess being aligned with said second axis and being intersected by said first axis and said machining axis.

2. A fixture assembly for holding a nozzle blank having a spherical end for the forming therein of a plurality of spray orifices lying on and distributed about an imaginary cone having an axis hereinafter called the spray-cone axis and an angle hereinafter called the spray-cone angle, the orifices being formed by electric-discharge machining by a wire moving along a line hereinafter called the machining axis, said fixture assembly comprising a base, a gage block slidably mounted on the base and having a series of steps progressively increasing in level from one step to the next, a pivot block mounted on the base for angular movement about a first axis perpendicular to the machining axis and containing a second axis angularly movable with the pivot block in a plane perpendicular to the first axis and containing the machining axis, the pivot block being engageable with the steps of the gage block individually, engagement of the pivot block with a particular step being produced by a particular position of the gage block with respect to the base and producing a particular angular position of the pivot block about the said first axis and a particular angle between said second axis and the machining axis determinative of a particular spray-cone angle, an adapter block mounted on the pivot block for angular movement with respect thereto about said second axis and being held against movement toward and away from said first axis, an adapter detachably connected to the adapter block and adapted to mount the end of the nozzle blank away from its spherical end to give the axis of the nozzle blank an angle with said second axis determinative of the angle between the spray-cone axis and the axis of the nozzle blank, a headblock having a conical recess in a side facing the adapter and adapter block, and means mounting the headblock on the pivot block for adjustment along said second axis, the conical recess being aligned with said second axis and being intersected by said first axis and said machining axis, the conical recess having at one side an opening through which the machining axis extends into the conical recess.

3. A fixture assembly, as specified in claim 2, the adapter block being circular and cylindrical, said first axis being adjacent one end of the pivot block, the pivot block having a circular cylindrical opening formed in a portion extending from the other end of the pivot block to a mid region thereof, the circular cylindrical opening having its axis coincident with said second axis and receiving and fitting the adapter block, the adapter being detachably connected with the end of the adapter block toward said first axis, the fixture assembly further comprising an index plate detachably connected to the end of the adapter away from said first axis and extending radially outwardly beyond the adapter so as to overlap said other end of the pivot block, the index plate having in a region overlapping said other end of the pivot block a plurality of peripherally distributed openings equal in number to the plurality of spray openings to be produced, the fixture assembly further comprising a retractable member positioned in said other end of the pivot block so as to be selectively insertable in the openings in the index plate for fixing the adapter against angular movement about said second axis with respect to the pivot block.

4. A fixture assembly as specified in claim 2, the base comprising a floor and upstanding spaced parallel ears extending upwards therefrom, the gage block being slidable along the floor, the pivot block being mounted on and between the ears, the pivot block carrying a fixed cylinder engageable with the steps of the gage block.

5. The fixture assembly specified in claim 2 and further comprising an adjusting screw extending through the headblock in threaded engagement therewith, one end of the screw abutting the pivot block, the other end having a large disklike head exterior to the head block and carrying about its periphery markings indicative of various radii of spherical ends on nozzle blanks to be machined, the adjusting screw being angularly movable by manual engagement of its head to bring the various markings on the head to a reference marking on the exterior of the head block radially outward of the head and simultaneously to produce various amounts of protrusion from the head block of the end of the adjusting screw abutting the pivot block and consequently various positions of the head block with respect to the pivot block as well as various spacings of the conical recess in the head block from the adapter.

6. A fixture assembly as specified in claim 5, each of the pivot block and the head block having first and second parallel spaced bores, the first and second bores of the pivot block being aligned with the first and second bores of the headblock, respectively, the fixture assembly further comprising a pair of coil springs for maintaining the adjusting screw in abutment with the pivot block, one spring lying in the first bores and having one end tied to the pivot block and the other end tied to the headblock, the other spring lying in the second bores and having one end tied to the pivot block and the other end tied to the headblock, the fixture assembly further comprising a set screw extending through the disklike head of the adjust ing screw in threaded engagement therewith into abutment with the exterior of the headblock for fixing the adjusting screw against adjustment.

7. Fixture for vertical drilling of a hole pattern in a nozzle,

comprising:

a rotatable adapter block;

a pivot block with rotatable mounting means rotatably supporting the adapter block thereon, and supported by tiltable mounting means to tilt the two blocks from a horizontal position about a horizontal pivot axis (52) of the pivot block;

the axis (58) of drilling being perpendicular to the horizontal pivot axis (52) and intersecting same;

nozzle mounting means on the adapter block for supporting anozzle 30)to be drilled; said rotata le mounting means effective to rotate the adapter block in the pivot block for rotationally positioning the nozzle for drilling with a ring of holes a plurality of which are equiangularly spaced apart;

the axis (56) of rotation of the adapter block being perpendicular to the horizontal pivot axis (52);

said tiltable mounting means comprising block means engageable at a point on the pivot block to set the tilt angle by setting the height of the pivot block at that point;

said nozzle mounting means comprising adapter means which is revolved by the adapter block, as the adapter block rotates, to carry the nozzle into rotational positions as described;

a headblock on the pivot block engageable with the nozzle tip; and

means establishing cooperation to support the headblock on the pivot block for movement along said axis (56) of rotation and to support the adapter means on the adapter block for movement along said axis (56) of rotation, for commonly adjusting the nozzle tip linearly into vertical alignment with the axis (58) of drilling aforesaid.

8. The invention of claim 7, the rotatable mounting means characterized by:

a rotary indexing plate selectable from substitutable indexing plate means each with a different number of indexed positions affording a precise number of holes per ring.

9. The invention of claim 7, the tiltable mounting means characterized by:

a spacer (50) selected from substitutable gage block means each of a different measurement determinative of a precise spacing.

10. The invention of claim 7, the nozzle mounting means characterized by:

an adapter (47) selected from substitutable adapter means each forming a different angle to the adapter block determinative of the precise angle of the cone pattern axis to the nozzle axis.

II! i t i

Claims

1. A fixture assembly for holding a nozzle blank having a spherical end for the forming therein of a plurality of spray orifices lying on and distributed about an imaginary cone having an axis hereinafter called the spray-cone axis and an apex angle hereinafter called the spray-cone angle, the orifices being formed by a tool moving along a line hereinafter called the forming axis, said fixture assembly comprising a pivot block (45) mounted for angular movement about a first axis (52) perpendicular to the forming axis and containing a second axis (56) angularly movable with the pivot block in a plane perpendicular to the first axis and containing the forming axis, a particular angular position of the pivot block about the said first axis producing a particular angle between said second axis and the forming axis determinative of a particular spray-cone angle, means for mounting the end of the nozzle blank away from its spherical end on the pivot block to give the axis (57) of the nozzle blank an angle with said second axis, determinative of the angle between the spray-cone axis and said axis of the nozzle blank, said mounting means enabling the nozzle blank to be movEd about said second axis with respect to the pivot block for the formation of the various spray orifices of a given plurality thereof lying on the same spray cone, and a headblock (48) having a conical recess engageable with the spherical end of the nozzle blank and being mounted on the pivot block, the conical recess being aligned with said second axis and being intersected by said first axis and said machining axis.

6. A fixture assembly as specified in claim 5, each of the pivot block and the head block having first and second parallel spaced bores, the first and second bores of the pivot block being aligned with the first and second bores of the headblock, respectively, the fixture assembly further comprising a pair of coil springs for maintaining the adjusting screw in abutment with the pivot block, one spring lying in the first bores and having one end tied to the pivot block and the other end tied to the headblock, the other spring lying in the second bores and having one end tied to the pivot block and the other end tied to the headblock, the fixture assembly further comprising a set screw extending through the disklike head of the adjusting screw in threaded engagement therewith into abutment with the exterior of the headblock for fixing the adjusting screw against adjustment.

7. Fixture for vertical drilling of a hole pattern in a nozzle, comprising: a rotatable adapter block; a pivot block with rotatable mounting means rotatably supporting the adapter block thereon, and supported by tiltable mounting means to tilt the two blocks from a horizontal position about a horizontal pivot axis (52) of the pivot block; the axis (58) of drilling being perpendicular to the horizontal pivot axis (52) and intersecting same; nozzle mounting means on the adapter block for supporting a nozzle (30) to be drilled; said rotatable mounting means effective to rotate the adapter block in the pivot block for rotationally positioning the nozzle for drilling with a ring of holes a plurality of which are equiangularly spaced apart; the axis (56) of rotation of the adapter block being perpendicular to the horizontal pivot axis (52); said tiltable mounting means comprising block means engageable at a point on the pivot block to set the tilt angle by setting the height of the pivot block at that point; said nozzle mounting means comprising adapter means which is revolved by the adapter block, as the adapter block rotates, to carry the nozzle into rotational positions as described; a headblock on the pivot block engageable with the nozzle tip; and means establishing cooperation to support the headblock on the pivot block for movement along said axis (56) of rotation and to support the adapter means on the adapter block for movement along said axis (56) of rotation, for commonly adjusting the nozzle tip linearly into vertical alignment with the axis (58) of drilling aforesaid.

8. The invention of claim 7, the rotatable mounting means characterized by: a rotary indexing plate (95) selectable from substitutable indexing plate means each with a different number of indexed positions affording a precise number of holes per ring.

9. The invention of claim 7, the tiltable mounting means characterized by: a spacer (50) selected from substitutable gage block means each of a different measurement determinative of a precise spacing.

10. The invention of cLaim 7, the nozzle mounting means characterized by: an adapter (47) selected from substitutable adapter means each forming a different angle to the adapter block determinative of the precise angle of the cone pattern axis to the nozzle axis.