US2793545A - Machine for boring oppositely tapering coaxial holes in spaced parallel wall parts - Google Patents

Description

May\28, 1957 N mc 2,793,545

MACHINE FOR BORING OPPOSITELY TAPERING COAXIAL HOLES IN SPACED PARALLEL WALL PARTS FiledApril 15, 1954 11 Sheets-Sheet 1 INVENTOR.

glmofeMBepgdicf,

WW, ATTORNEY.

y 28, 1957 E M BENEDICT 2,793,545

MACHINE FOR BORING 'oPPosITELY TAPERING coAxlAL HOLES IN SPACED PARALLEL WALL. PARTS 11 Sheets-Sheet 2 Filed April 15, 1954 27 INVENTOR.

v 12 Elmore/1B 0dr), 26wrzmm 133 134131 ATTORNEY.

May 28, 1957 E Emc 2,793,545

M. BEN T MACHINE FOR BORING OPPOSITELY TAPERING COAXIAL HOLES IN SPACBD PARALLEL WALL PARTS i Filed April '15, 1954 L 11 Sheets-Sheet 3 IN V EN TOR.

1 51 50 1 ElmoreMBezzedicf,

ATTORNEY.

I May 8. 1957 E. M. BENEDICT 2,793

' MACHINE FOR BORING POSITELY TAPERING COAXIAL HOLES m SPAG PARALLEL WALL. PA Filed April 15, 1954 RTS l1 Sheets-Sheet 4 IN VEN TOR.

ATTORNEY.

May ZS, BE'NEDlCT MACHINE FOR BGRI OPPOSITELY TAPERING COAXIAL HOLES IN SPACED PARALLEL WALL PARTS Filed April 15, 1954 ll Sheets-Sheet 5 ATTORNEY.

y 8, 1957 E. M. BENED T 2,793,545

ORING o MACHINE FOR B OSITE TAP ING COAXIAL HOLES IN SPACE ARALLEL WA PARTS Filed April 15, 1954 ll Sheets-Sheet 6 I INVENTUR. Elmore/V. Benedlcf, BY o usir'w.

ATTORNEY.

y 28, 1957 E. M. BENEDICT 2,793,545

MACHINE FOR BORING QPPOSITELY TAPERING COAXIAL HOLES IN SPACED PARALLEL WALL PARTS I Filed April 15, 1954 ll Sheefcs-Sheet 7 I H i r E3 E 5; V glmoreMfiinedicf,

ATTORNEY May 28, '1957 E. M. BENEDICT 2,793,545

ORING OPPOSITELY TAPERING COAXIAL V HOLES IN SPACED PARALLEL WALL PARTS Filed April 15, 1954 11 Sheets-Sheet s MACHINE FOR B INVENTOR.

ElmoreM media, BY I ATTORNEY.

Mayl28, 1957 E .BE NEDICT,,. 2,793,545 I MACHINE FOR BORI OPPOSITELY TAPERING COAXIAL HOLES IN SPACED PARALLEL WALL PARTS Filed April 15, 1954 11 sheets-sheet @9 166\ v 1&1 164 I INVENTOR.

Elmore/Hamid .121

K ATTORNEY 11 Sheets-Sheet 10 E. M. BENEDICT PPOSITELY TAPERING COAXIAL D PARALLEL WALL. PARTS May 28, 1957 MACHINE FOR BORING O HOLES IN SPACE Filed April 15, 1954 R .E M M J m m m MN r v E aa Mk Hmm HQ pmv. Q Q E fi mm B E B. m m v N J @V/L I m k NEE 3E Lwmsm E l, E 7. .Q

May 28. 1957 E. M. BENEDICT 2,793,545

MACHINE FOR BORING OPPOSITELY TAPERING COAXIAL HOLES IN SPACED PARALLEL WALL PARTS Filed April 15, 1954- 11 Sheets-Sheet 11 it go?" United States Patent 17 Claims. (Cl. 77-3) This invention relates to a machine for boring oppositely tapering coaxial holes in spaced parallel wall parts.

In prior practice oppositely tapering holes in parallel wall parts have been formed in separate and independent operations.

The principal object of the invention, as a matter of substantial economy of manufacturing operation, is to provide a machine in which the boring operation and the subsequent release of the work from the boring medium.

general character and appropriately different specific design when, according to choice, the directions of the tapers cut by the machine are to be reversed or when the operation of the machine is to be limited to the boring of the taper only in the anterior wall.

A further object is to provide a machine of the character stated in which all operative phases, including the opera tions of the boring bars, positional adjustments of the various parts, and the operation of the mechanism for controlling the operation of the motors are effected by power.

The invention comprehends a machine having the above essential characteristics and otherwise characterized by novel features of structure and combination whereby the above objects are served.

In the example selected for illustration the structural element in which tapers are to be bored is a water filled unit of a sectional boiler but it will be understood that machines embodying the invention may be used for boring oppositely tapering coaxial holes in spaced parallel walls of elements of different design, that is to say elements designed as parts of various structural assemblies 1 for different specific uses, for example, radiator units.

are accomplished serially in a sequence of steps involving relative movements of the various parts in what is essentially a single operation for tapering both of the holes.

The machine, among other essential features, includes a boring bar having a driving element and a boring head having diametrically oppositely located cutters, the cutters as oppositely located being for boring the tapers in the openings of the respective walls. In carrying out the above stated principal object the invention fundamentally provides for rectilinear posi'tionally adjustable relative movements of the driving element and the work and movements of the boring head relatively both to the driving element and the work, certain of which movements involvethe feeding of the cutters into and through the work and all of which movements are carried out in a cycle of operation involving a series of coordinated steps and an appropriate selection of the relation of the cutters for operation in a predetermined sequence.

As other essential features the driving element is arranged along an inclined axis and is rotatable abouta major'axis, preferably horizontal, and the boring head itself has an axis which extends in the same direction as the major axis and is carried by a part slidably and ad With these justably movable along the inclined axis. characteristics in mind further objects are to provide a machine having the capacity for appropriate selection of the directions and extents of the relative movements of the driving element, the boring head and the work, the durations of their periods of rest and the relative arrange- The drawings illustrate an embodiment of the invention which, as now considered, is preferred. In the drawings: Figure l is a front elevation of a machine in accordance with the invention, with the work unit, i. e., the structural element, shown as positioned on its carrier.

Figure 2 is a side elevation of the machine.

Figure 3 is a vertical transverse sectional view on the line 3--3 of Figure 2. 1

Figure 4 is a vertical transverse sectional view on the line 4-4 of Figure 2.

Figure 5 is a vertical sectional view on the line 5--5 of Figure 1.

Figure 6 is a horizontal sectional view on the line I 6-6 of Figure 2.

Figure 7 is a perspective view of one of two similar devices for clamping engagement with the upper portion of the structural element upon which the machine operates.

Figure 8 is a detail horizontal sectional view on the line 88 of Figure 3.

Figure 9 is a perspective View of one of two similarline 10-10 of Figure 3.

ment of the cutters, whereby, according to choice, the

tapers may be bored with their minimum diameters in either mean or extreme relation and in either instance their degree of angularity may be varied from the maximum permissive degree.

A further object is to provide a machine of the character stated in which several pairs of alining oppositely tapering holes may be simultaneously bored.

As other essential elements the machine includes separate motors for effecting the steps of relative movement of the boring head and the work and a mechanism for controlling the operation of the motors in respect to the directions, extents and sequences of such movements. With these characteristics in mind a further object is to provide a mechanism for controlling the operation of the motors which has a governing element specifically designed for effecting the particular directions, extents and sequences of the steps of movement of the driving element, the boring head and the work which element may be re- Figure 11 is a horizontal sectional view of one of two similarly constructed and acting valves for controlling respectively the movements of the carriage for the struc tural element and the movements of the slidably mounted spindles of the boring bars, the valve shown in this figure being the valve which controls the movements of the carriage.

Figure 12 is an elevation of the governing element which is. shown inthe form of a rotatable electrical I contact-carrying disk.

placedby a similarly functioning element of the same Figures 13 and 14 are complementary graphs as indi- :cated by the bracket showing the sequence of the steps of movement of the boring head and the work when the Figure 15 is a central horizontal sectional view on the line 15-15 of Figure 2 of one of the boring bars and the associated parts, the boring head and the work being diagrammatically shown in their relative positions prior to the. commencement of the boring operations. It will be understood that the several boring bars are of similar construction. Figures 16 to 20 are a series of diagrammatic views of similar character in the same horizontal plane as Figure 15 I which, like the diagrammatic showing'of Figure ISQaS- 5 sume the boring of tapers in the two walls in which the" minimum diameters'are in mean relation: and thefriiaximum diameters'are' in extreme" relation. These fi gtir'esf show the relative positions of the "boring head' and' 'the, work'in the different steps of operation. In'theseftig' ir'es', the'work is shown "in'sectiontaken in'the same plane in i which his 'showni'n'Figure 15'. Figure 16 "showsthemelative positions of thc b oring headandthe 'work when the work been advancedio a pos'itionin which'the outerfonanterioi" face of its 541 terior'w'allis substantially coincident'with'th boring' head andthe opening"infthegjante I v, opening being formed in the'finoldi n gioperationftfi be: cut-with-ataper'-is presented mm ering;

Figure- 17 shjows 'thei"elative "positions" of t he horing head ahdthe-workwheii'thefwork been shif 'd'fr the position show'nin Figure""16"t:o"a position the 1inne'r 'on anferior face of the posteriorfwall is' sub'; stantially-coincident "withthetace of 'thef borihea' andtheopening'iri'the posterior wall (the openin m formedinthe inoldingoper ion) is 'presente to cutterslv: "1 ml? i v t Figure 18 shows the boring head and the work when the work has been shiftedfr'om the position shownin j Figure 16 to a position-in which the-posterior or outer '30 face'of the posterior-wall is located'at a-suitablejdis'ta in advance ofth'e 'l-eadingmractive edges of the cutters in preparation for the-movement of the boring head through an initial retractile step, thereby to'pullj all of the cutters through the'tapered opening which' hasbee n cut in the posteriorwall.

Figure 19 shows the'work in the same position in which it is shown in Figure 18 but with the boring head at the. completion of its first step of'retrac tilemovemeht.

Figure 20 shows the work as shifted from" its position shownin Figure 19 back to its original position which is shown in Figure'lS. This movement of the work enables the' bon'ng head to be moved back'toits original position as shown in broken lines. Figure 21 is 'adiagram showing the concentric rotation of the axial center of the spindlewhich carries the "boring head about the fixed'axisof" rotation of the gbor- Figure 22 is a diagram showing the relation of the central axis of the spindle which carries the boring head, the g fixed central axis of *rotatibnof the boring bar and the central axis of the boring head when the'work and the boringheadhave been brought into the relation shown in Figure 16. i is Figure 23 is a diagram showing the manner in which the central axis of the" boring head'moves' away from the fixed central axis of rota-tionof the boring barwhen the boring headis advanced in 'the direction of the axis ofits spindle in the course of the cutting operations.

Figure 24 (Sheet 4') is ahorizontal section on theline 2424'ofFigu re-5, showing details of the fluid'motor" for effecting the movements of the carrier'for'the"struc-" tun-a1 unit. Figure 25 is a horizontal sectional view showing details of themanually operated valve for controlling" the op eration of the work clamping means, the valve body'bein'g shown inelevation. 1 i Figure 26 is a vertical sectional view on the line 2626 of Figure 25 showing the path of flow of the operating fluid to effect the clamping action. I Figure-27 is'a vertical sectional view on the line 2 7--2 7 of Figure 25 showing the valve body in the same position and the path of return flow of the operating fluid. Figure 28 isa wiring diagram showing the solenoids for the operationot the valve bodies of thefiuid mast-W illustrated in Figures 5 and 24 and the motor driven I contact carrier which controls" the energiziation and deenergization of the solenoids.

Figures 29 and 30 are complementary graphs as indicated by the bracket showing the sequences of steps of movement of the boring head and the work when the tapers to be cut have their minimum diameters in extreme relation and their maximum diameter-s in mean r el a tio n,, gu 2 ng a e a-p b ihebperl xe mevem ntsot, the Boring head and Figure 30 a graph of the operative.

being shown in section in the same plane in which it is shown in Figures 15 to 29.

Figure 31 shows the boring head and the;work in their,

relative positions prior to the commencement of theboring operations and after their completion Figure 32 shows the relatiye positiolisv,of the boring. d d e-w rk when th rw rkhas been a vanced ,to a position in whieh'the outer or anterior face of the anterior wa t is substantially coincident withthe end face.

of the boring head and the opening in the anterior. wall is Pr llt d 1 t 1 T-.

Figure 3 3 show s the relative positions, of the boring head and the work at thecompletionof the. cutting of the taper the opening in the anterior wall.

Figure 34 shQW, ,,th r la ive. positions of the boring". head and the work immediately priortothe cuttingof the theposterior wall. Thesepositionsmaybe called "COIlQlltlPIlil'lgi positions in that ,theyiare. in preparation,v

taper for the cutting of thetaper in, the: posteriorrwall. a

Figure 35 shows therelative. positions. of the boring I headandthework whenithe.. .work. has beenshiftednto present the anterior face, of theposterior wall to the-boring h d I Figure 36 shows the relative positions of the-work and the boring head Whenthe taper has been cut in the opening in the posterior wall,

Figure 37 sho'ws the .relative positions of the boring head and the ,work when the boring head has'been com-. pletely withdrawn from thework and both the boring head, and the fwork have been restored to their original 7 positions.

Figure 38 .is a schematic side elevation showing a ma- I chine of modified construction in which the work unit is zontal plane as Figures 15 and "16 through 20' and are arranged conjointly .to' constitutea graph (as indicated by the bracketf'showing the relatiyepositionjs of the work and the: boring head in correspondence to the positions shown'individually in" Figure'sld'to 20' respectively.

As an example of work selected for illustration the drawings show a" section orunit U offa sectional boiler of a wellk'nown generalty'pe','the details here pertinent being sufficiently shown in Figures 1,3, 5' and 15 through 20. In the assembled "boiler units ot the construction shown in the drawings are mounted in superposed rela-,

tion and'in'each instance'includeia horizontal marginal water chamber C (Figure 5'). Thewaterchambers of adjoining units a'r'ej'in open communication with one another'at'any desired numher of points, In the exam-v ple shown the ":oinrniinication,is at three symmetrically spaced points fFoithe purpose ofes't'ablishing such communicatiofieach unit is fo'rmed withhoriiontal extensions "(Figure" 1')f which project QradiaII y Loutward and are 'rcularly pan/ed; These hayeiparallel walls as 'best showninFigure's lS'thro'ugh 20', one wall, designated 5 A, being anterior and the other, designated P, being posterior. In the molding of the units openings are formed in the walls A and P and the machine of the invention 'bores tapers in these openings. In the assembly of the units to form the boiler the tapering openings are in alinement to provide continuous vertical water flow passages. The adjoining units are connected and their meeting faces sealed by thimbles of well known construction which is standard practice are fittedclosely in the tapering walls of adjoining extensions K and have external surfaces which conform in taper to the tapers of the openings of the adjoining extensions. Since these thimbles are well known and form no part of the invention their illustration is deemed unnecessary.

In the example shown the openings 0 of one series are of substantially greater diameter than the openings of the other two series. The openings of greater diameter are provided in order that the water passage which they delimit may serve also as a casing for awater heating coil connected to the hot water supply line. As shown in Figure 3 the unit is positioned for the drilling of the tapers with the extensions K in which the openings of greater diameter are formed centrally located at the top and the extensions K in which the openings of less diameter are formed located at or near the lower side.

The machine includes three boring bars (using the term bar in the sense of an organization), one for each pair of alining openings. The boring bars are of structurally similar character and include boring heads which have the same movements similarly and sirnultaneously performed. The illustration in detail of one boring bar will therefore serve for all, the bar selected for illustration in Figure 15 being shown in relation to an extension K in which openings of less diameter are formed.

Each boring bar includes a driving element for the boring head. In the preferred embodiment (Figures 1 through 37) the driving element has a fixed mounting and the work has a sequence of rectilinear movements relatively to the driving element. Within its purview the invention comprehends relative movements of the Work and the driving element by movements of the driving element relatively to' the Work as fixedly mounted (Figure 38). In either case the boring head has move ments along an inclined path relatively both to the driving element and the work.

The frame of the machine (Figures 2, 4 and includes a horizontal base 1 which carries fixed front and rear upright pedestals 2. and 3 positioned in parallel transverse planes.

The boring bars are indicated generally at 4 and as shown in Figure in. each instance have a driving element 5 in the form of a hollow shaft inclined along a central axis W. The shaft 5 carries front and rear end journals 6 and 7 respectively concentric with a major axis X which is preferably horizontal and is at all times coincident with the common axis X0 of the alining openings O. The angle of the axes W and X determines the maximum permissive degree of the taper. The shaft 5 drives, and preferably encloses, a spindle 9 inclined along the axis W and mounted for longitudinal sliding movement relatively to the shaft 5. The axes W and X meet or intersect at a fixed point Z appropriately located behind the rear end face of the spindle 9. At its rear end, i. e., its end beyond the point Z, the spindle carries in driving relation a boring head 10 located beyond the rear journal 7 and in projecting relation to the shaft 5, thehead 10, having a central horizontal axis Y which, prior to the boring operation, is coincident with the major axis (3 of the journals 6 and 7.

The driving connection between the boring head it) and the spindle 9 is of detachable nature, thereby to enable the angular adjustment of the cutters carried by the boring head relatively to the spindle 9 or the substitution of a boring head of appropriate diameter for the particular openings, in which tapers are to be bored. The inner end face of the boring head 10 is preferably in a vertical plane, that is to say a plane normal to the axis Y, and abuts the rear end face of the spindle 9. The driving connection of the head 10 is in the well known form of an extension 11 of annular cross section and reduced diameter, such extension being coaxial with the head 10 and having the usual slight degree of taper. The extension 11 fits comformably in a recess 12 open to the rear end face of the spindle 9, the annular wall of the recess having a taper corresponding to the taper of the extension 11. The head 10 is maintained in driven relation to the spindle 9 by a screw 13 fitted in a central axially extending opening in the head with its shank projecting beyond the extension 11, the projecting portion of the screw shank being engaged in a threaded recess 14 in countersunk and coaxial relation to the recess 12. When the screw 13 is tightened the extension 11 is drawn into tight wedging contact with the wall of the recess 12. When the screw 13 is backed off the boring head may be angularly adjusted relatively to the spindle 9, thereby to vary the extent of the radial movement of the cutters relatively to the axes X and X0 consequent to the movement of the spindle 9 in the hole boring opera tion. It will be noted that the axes W and Y lie in a diametrical plane (which is assumed as the plane of the section of Figure 15) and that the axis Y is shiftable in this plane relatively to the axes X and X0 as thespindle 9 is advanced in the hole boring operation. If, prior to the start of the operation, the cutters be positioned with their leading edges in this plane (as shown in the drawings) the cutters will have the maximum extent of radial movement relatively to the axes X and X0 as the spindle 9 is advanced. However if the cutters by angular positional adjustment of the boring head 10 be originally positioned with their leading edges in a diametrical plane at an angle to the plane which includes the axes W and Y the extent of the radial movement of the cutters relatively to the axes X and X0 as the spindle 9 is advancedwill be decreased in proportion to the increase of angularity of the intersecting planes with the results (1) that a positional adjustment of the boring head 10 through an angle of from the position assumed in the drawing will reduce the extent of the radial movement of the cutters relatively to the axes X and X0 consequent to the advancing movement of the spindle from the maximum extent assumed in the drawings to zero, and (2) an angular positional adjustment of the boring head 10 beyond an angle of 90 and up to an angle of will reverse the direction of the radial movement of the cutters relatively to the axes X and X0 and the extent of such reversed radial movement will be progressively increased to a maximum at 180.

The shaft 5 carries in fixed relation suitably spaced internal sleeves 8 which serve with a minimum of frictional contact for guiding the spindle 9 in its slidable movements. The shafts 5 are mounted in the pedestals 2 and 3 by means of ball bearings 17, the inner bearing rings being mounted fast on the journals 6 and 7. The shafts 5 of the two lower boring bars are directly mounted in bearing blocks 15 and 16 carried by the respective pedestals 2 and 3. Adjacent the pedestal 3 each shaft 5 is formed with an inwardly extending cylindrical face 18 concentric to the axis X. Eachshaft 5 has an extension 19 beyond the journal 6 and concentric to the axis X to which a driving pulley 20 is connected by screws 21, the pulley being directly mounted upon an adapter clamped between it and the end face of the extension 19.

The spindle 9 is driven from the shaft 5 by means of a suitable key 23 mounted for longitudinal movement in either direction relatively to the shaft 5, the key according to its direction of longitudinal movement effecting the advancing or retractile movements of the spindle. The key 23 has a secure fit in a ,diametrical opening 25 formed inthe-spindle9. To insure this the key is made intwo parts 25 and 26' having cooperating wedge faces. These faces are formed to delimit an opening for a diametrically'arrange'dscrew 27, a part 28 of the opening wholly-within the'key part ZS 'being threaded for cooperation-with the screw. The function of the screw 27 is relatively toexpand'the key parts into strong frictional contact with the-wall of theopening 24. T he'end portions of the key parts 25 and '26 project suitably beyondthe spindie 9'and are located in longitudinal slots 29 corresponding in width to the diameter of the key and formed in the shaft between its cylindrical faces, thereby to couple the spindle9in'driven and slidablyrnounted relation'to the shaft 5. The key 23 is accordingly movable in "either direction, lengthwise of the shaft, in the slots 29,-its movement being effected by 'acollar 3t) rotatable with the shaft '5 'and'slidably mounted upon its face 18. The'collar' 30 is provided "with diametrically opposite openings 31 and 32, the opening 31'giving'access to the head of the screw '27 and the opening 32 accommodating with a suitableloose but driving fit that portion of the key part '25'which projects beyond the face 18. The movement 'of the collar 30 along the face 18 is transm'ittedby the key 23 to the spindle 9.

The boring head carries radially projecting cutters arranged in diametrically opposite relation and preferably provided inpairs, the cutters of 'a' pair being in longitudinal'alinement and being roughing and finishing cutters respectively. The cutters of one pair form the taper in the opening of the wall A and the cutters of the'second pair form the taper in the opening of the wall P. According to the angular positional adjustment of the boring head "10' relatively to the spindle 9 the opposite tapers maybe cut in either direction and in various degrees of angularity less than'rnaximum.

Figures through assume that the tapers will be cut with-their permissive maximum 'angularity and with their minimum diameters in mean relation. The cutters are arranged in first and second pairs, these terms being used with reference to the sequence in'which the pairs of cutters operate. In Figures 15 through 20 the first cutters 33 and 34 cut the taper of the hole in wall A and the second cutters 35 and 36 cut the taper of the hole in the wall P. The finishing cutter of each pair follows "the roughing cutter and projects a few thousandths of'a'n inch, e. g. .015, beyond it. In the example assumed by Figures 15 through 20 the cutters 33 and 34 have a slightly greater projection from the periphery of the head v10 than the cutters 35 and 36, i. e., of the order of .019 inch. the cutters 33 and 34 is' provided for the reason that while they are cutting the taper of the hole in the wall A the cutters 35 and 36 must move through the hole without contact with its wall.

In'the example shown in Figures 15 through 20, as the boring head '10 is advanced the cutters 33 and 34 approach'the major axis X and the cutters 35 and 36 move away from it. Since the cutters 33 and 34 have a greater degree of projection from the boring head than the cutters 35"and 36 they are operative to cut the taper in the opening of the anterior-wall. These figures assume that in any position of the boring head 10 consequent to the movement of the spindle 9 along its axis W the pairs of cutters are respectively at their perrnissible maximum and minimum distances radially from the axis X. By the angular adjustment of the boring head in either direction about its axis Y through an angle of 90 from the positionassumed in Figures 15 through 20 the extent of the radial movement of the cutters relatively to the axes X and X0 as'the boring head is advanced may be progressively'varied. In this manner the angularity of the tapers i'n'the'two walls maybe predeterminately decreascdfrorn the permissive maximum degree. With reference to the position of the boring head shown in Figures 15 through 20 i ts' angular adjustmentthrough an angle of 90 pro- This greater degree of projection of gressively reduces the "extent .of radial movement ofthe cutters 331and 34 relatively to the.-axes.X and X0 asthe boring head is advanced, whereby theangleof thetaper ofzthe opening in thewall vA may be=progressively reduced frommaximum {to zero .at 90.- When the. angular adjustment .of the'boring head 10. about its axis-Y ;is to be continuedbeyondl90 from the position assumed in Figures 15 through .520 and up :to'180"- the taper is cut in the wall A by the cutters 35 and 36 ,and in the wall P by the cutters 33 .and 34. :In such instances thecutters 35 and 36 are positioned toproject-radiallythrough an appropriately greaterzdistancefrom the periphery of the boring headthanthe cutters 33 and 34 and the directions of the tapers are reversed from the directions-assumed in Figures 15 through 20. a

A separate electric. motor is preferably provided for each shaft 5. The motor 37 for the upper boring bar (Figures 1,2 and 5 beingconsidered) -is mounted on a bracket 38 secured by boltsto the flat upper edge faces of the pedestals Zand 3 and .its shaft carries a pulley '39 connected by abelt or belts 40-to the pulley 20-of the shaft 5 of the upper boring bar. 'Thetmotors 41 for the shafts 5 of the two lower boring bars are mountedton laterally projecting brackets 42,. each formed with an attachment plate43-securedbyboltsto the flat inclined side edge faces .of the pedestal 2, the shafts of the motors 41 being similarly belt geared .to the respective pulleys 20 of theshafts 5 of the two lower boring bars.

The work U is :securedin upright position beyond the boring bars in ,a plane normal to theaxis X. The supports for the workunit .and the boring bars .may be re garded as companion elements having rectilinear relative movements, one element being fixed and the other being movable. 'In the preferred embodiment the unit U is mounted upon a carrier 44 (Figures 1, 2, 3 and 5) which consists of a base 45 and a frame .46 mounted upon it in upright relation in a transverse plane. Theframe base 1 is provided along its sides with projecting flanges .47. The carrierbase 45 has depending side walls 48 to the lower faces of which securing strips 49 are attached, these engaging under the flanges 47 and preventing any upward or canting displacement of the carrier. The frame base 1 is preferably formed in its upper face with a longitudinal way 50 having sides which flare upward and the carrier base 45 is fashioned with projections 51 on its under face which are inclined conformably to and bear against the sides of the way 54 The frame 46 conforms in general outline'to the work and has an upward extension 52 to accommodate work clamping means. This preferably includes a vertically movable cylinder 53 hydraulically operated in relation to a fixed piston 54 provided at the lower end of a stem 55. The piston carrying stem 55 projects through the upper head of the cylinder, is pendent from the bow or cross piece at the upper end of the extension 52, and has passages for the flow of the operating fluid into and from the .spaces at each side of the piston. The cylinder 53 is formed with vertical diametrically opposed external flanges .56 which bear against the vertical side pieces of the extension 52 and carry work engaging elements 57; These are shown in detail in Figure 7 and are secured by screws 58 to the lower ends of the flanges 56. The elements 57 have their inner faces formed with recesses 59 which accommodate and center the work unit extension K. Other work engaging elements 60 are arranged on the carrier base 45 and are secured by screws 61 to the side bars of the frame 46. The elements 66 engage the two lower extensions K of the work unit U and have theirinner faces formed with recesses 62 which similarly accommodate and center these extensions. It will be apparent that when the cylinder 53 is moved to its lower position and held in such position under the pressure of the oper ating fluid the elements 57 and 60 will engage the annular walls of the extensions K and will cooperate in securelyholding the work unit within the frame of the carrier a-positionunwhich-its openings 0 are, and

at all times remain, concentric with extensions of the axes X. Theflow of the operating fluid to and from the cylinder 53 is controlled by a manually operated valve 63 (Figure 2).

The carrier44 is moved rectilinearly in either direction and through steps of appropriate length by a fluid motor 64 (Figures and 6) having a fixed piston 65 mounted on a stem 66 and a movable cylinder 67. The stem 66 is secured to a lug 68 mounted on the frame base 1 and the cylinder 67 carries a centrally located axially projecting post 69 tapped into an opening in the inner edge face of the carrier base 45. The piston carrying stem 66 is similar in construction to the stem of the work clamping means 55. The cylinder 67 is preferably slidably mounted in an opening in the pedestal 3, specifically in a block 74) provided on the frame base and located within an opening 71 formed in the pedestal 3 to reduce weight. The slidable movements of the spindles 9 are effected by a vertical spider 72 mounted in a transverse plane (Figures 4 and 5). In the example shown the spider 72 is of generally inverted Y shape and is formed with three arms 73, each serving for the operation of one of the spindles. The spider 72 is prevented from turning about a hori- With the work remaining in position D the boring head zontal axis by a guide rod 74 extending between the pedestals 2 and 3 and passing through an opening in the upper arm 73 of the spider. The spider 72 directly effects the movements of the collars 30. For this purpose each collar is formed with a circumscribing annular flange 75 in a plane normal to the axis X and each arm 73 carries at its outer end a pair of antifriction rollers 76 tracking upon opposite side faces of the flange of the corresponding collar. The spider 72 is operated by a fluid motor 77 which has a fixed piston 78 and a movable cylinder 79. The pedestal 2 carries a horizontally projecting bracket 80 and the stem 81 of the piston 78, which is similar in construction to the stem 66, is fixed to, and projects horizontally from the end wall of the bracket 80. The spider 72 has a central opening in which the cylinder 79 fits, the spider being clamped in position between an annular flange 82 on the cylinder and a collar 83 threaded upon the end of the cylinder. The pedestal 3 serves as a support and guide for the cylinder 79 and is formed with an opening 84 within which the cylinder 79 has its sliding movement. The bracket 80 is conveniently in cylindrical form, is attached by a screw 85 to the pedestal 2, and has an opening 86 which gives access to the nut 87 by which the piston stem 81 is secured.

In the preferred embodiment shown the work U has four vertical planar positions indicated respectively in Figures 15, 16, 17 and 18 and also respectively in Figures 43, 39, and 41 as B, C, D and E and the boring head has four positions indicated respectively in Figures 15, 17, 18 and 19 as F, G, H and I and also respectively in Figures 43, 40, 41 and 42. I

Figure 15 shows the work and the boring head in relatively inactive positions. In this figure the work unit U is in position B and is suitably spaced back of the boring head 10 which is in position F.

The first step in the operation of the machine is shown in Figures 16 and 39. In this step, while the boring head remains stationary in position F, the work is advanced from position B (Figure 15) to position C in which the anterior face of the anterior wall A is in a plane substantially coincident with the vertical plane of the leading or active edge of the cutter 33 and the wall of the anterior opening 0 is operatively presented to the cutters 33 and 34. With thework remaining in position C the boring head is advanced in a direction opposite to that of the advancing movement of the work to position G (indicated in broken lines) whereby the cutters 33 and 34 are fed through the anterior opening 0 and cut the required taper of its wall. The tapering cut of the anterior opening 0 is sufiiciently shown in Figure 17 by resort to the expedient of dot and dash extension lines.

The second step of movement of the work is shown in is advanced in a direction opposite to that of the advancing movement of the work to position H (indicated in broken lines) whereby the cutters 35 and 36 are fed through the posterior opening 0 and cut the required taper of its wall. The tapering cut of the posterior opening 0 is shown in Figure 17 by resort to the expedient of dot and dash extension lines.

After the tapers have been cut in the anterior and posterior openings as above described, the work is moved to positions which enable the return of the boring head 10 to its initial or inactive position shown in Figure 15. These movements of the work and of the boring head are shown in the order of their succession :in Figures 18, 19 and 20 (in which the final position of the boring head is shown in broken lines).

With the boring head remaining in its position H as shown in Figures 18 and 41 the work is then advanced in the same direction as before through its third step of movement (shown in broken lines in Figure 41) to position E shown in full lines in Figures 19 and 42. This position of the work permits the boring head to be moved in the direction opposite to that of its previous movements, i. e., retractile direction through a first step in its Withdrawal from the Work. This step is shown in Figures l9 and 42 and involves the movement of the boring head to position I while the Work remains in position E. The advance of the work to position E insures that the cutters may be withdrawn from the posterior opening 0 without contact with its wall. In position I of the boring head the cutters 36 and 34 have been completely withdrawn from the posterior opening 0 while the cutters 35 and 33 remain in such opening but without contact with its Wall.

With the boring head remaining in position I the next step in its withdrawal from the work is the retractile movement of the work (as shown in broken lines in Figure 42) from position E back to its initial position B. These relative positions of the work unit and the boring head are shown in Figures 20 and 43. At this stage the cutters 35 and 33 are located behind the anterior wall A of the work and the cutters 36 and 34 are located within the anterior opening 0 but without contact with its wall.

After the work has been returned to its initial position B and while it remains in such position the boring head is moved through the second and final step in its withdrawal. In this step the boring head is moved from position I back to its initial or inactive position F (indicated in broken lines in Figures 20 and 43), the cutters 35 and 33 being withdrawn from the anterior opening 0 without contact with its wall. The work and the boring head at such time are in the relative positions shown in Figure 15 At this stage the work is removed from the carrier 44 and a new unit U having holes in which tapers are to be cut is mounted in the carrier, such a new unit being assumed in Figure 15. The cycle of operations is thereupon repeated.

As will appear from the foregoing description in the operation of the machine the boring head and the work unit each have a cycle of step-by-step movements, these being coordinated and constituting a series of operative steps in each of which the boring head and the work unit are in cooperative relation.

By way of recapitulation these steps are graphically illustrated in Figures 13 and 14 which are to be read together, Figure 13 illustrating the cycle of movements of the boring head and Figure 14 illustrating the cycle of movements of the work unit. g

' xFigures'l-3 and 1.4 are to be considered in relation to theprevious description of the-..-severa1- steps asqbasedtupon the disclosures of .Figures .15 through '20 land Figures '39 through 43. With the boring head in position-F and. the work unit in vwhich tapers are to be cut in -position B (Figure 15) the first step S1 as shown by the graph of'Figure 14 is the-movement of the work unit from position'B to position C (Figures 16 and 39). With the work unit in position C the second step S2 as shown by the graph'of Figur'e '13 is the cutterfeedingmovement of the boring head from position-F toposition G (Figures 16 and 39 and-17 and 40) in which thecutters 33 and 34 form theztaper. of thewall of the anterior opening O.- With the boring head inposition Gthe third step S3 as show-n'by the graph of Figure 14 is the movement-ofthework unit formpositi'onCtoposition D-(Figures 17 and 40). With the --work unit in position D the fourth step S4 as shown by thegraph of Figure 131's the cutter feeding-movement of thc'boring head from position G'to position H (broken lines'Figure 17) in which thecutters35 and '36 torm'the taper of the wall of the :posterior opening 0. .With the boring-head in position I-I the'fifth step S5 as shown by the graph of Figure, 14 is the movement of the ork unit from position D to position 'E (Figures 18 and 41). Withthe WOl'kjUIllt in position E the sixth step S6 as shown by the graph of Figure 13 is the retractile movement of the boring headfrom position H to position I (Figures 19 and 42). With the boring head in position I the seventh step S7 as shown by the graphof'Figure 14 is the movement of the work unit from position E to position 8 (Figures 20 and 43). With the work unit in position B the eighth step S8 as shown by the graph of Figure 13 is the movement of the boring head from position I- to position F (Figure 15 and broken lines of Figures and 43). At this stage the work unit in which tapershave been cut is removed and. a work unit in which tapers are to be cut is positioned and secured upon the carrier.

In respectto the foregoing description of the operative steps of movement of the parts it will be seen that the axis W of theshaft.5 and spindle 9 rotates about the major axis X of the journalso and 7 (Figure 21) and as the spindle 9 is advanced in the operation of the machine the'ax-is W generates opposed cones which have their apices at the point Z. With the boring head and the work unitin theirinactive positions as shown in Figure 15 the horizontal axis -Y of the boring 'head is alined or coincident with the axis X of the -journals-6 and 7 (Figure 22). When the boring head is moved throughthe steps S2-and-S4 (Figures 16 and '18) its axis Y hooves away from the axis X but is maintained in parallel relation to 'it. Thiswill be-apparent-from a comparison "of Figures 22' and 23. I From the foregoing description it will be apparent that the taper in the anterior wall'isformed by the pair r of cutters-whieh have the greater degree of projection from the "periphery-of the boring head; that when the taper-is to be out with itsmaximum diametersin extreme relation and its minimum-diameters in mean relation, the cutting of thetaper' isproduced by the cutters which move radially toward the -axis X; and that when the taper-is to be cut with its minimum-diameters in extreme relation .and its'maximum diameters in-mean relation the cutting of the taper is producedby the cutters which move away from the axis X.

Referring in detail to the cutting of the taper with itsrmaximum diameters tin-extreme relation and its minimumdiameters=inmean relation as shown-in-Figures 15 through 20 and "39 through 43:

In the movement of the boringhead through the-step SZ-tlro-taperis cut in the wall of the interior opening 0 by the cutters-33 and 34"witlrits" maximum and minimum diameters rcspectivelyat the outer and inner faces of the anterior wall A. This is for the -reason-that :while the axis .3 of the borinng head 'is being moved away from the axis X the cutters 33 ;and 34 are being, progressively moved radially nearer to the axis X, thereby c-utting spirals ofprogressively.diminishing diameters andproducing the tapering out which is best illustrated by the extension'lines of Figure 17. When the boringhead is moved through the step S4 (Figure 17) its axis Y continues, in parallel relation, to move away from the .axis X. In the movement of the boring head through the step S4 the taper is cut in the wall of the posterior opening 0 by thecutters 35 and 36, this taper having its minimum and maximum diameters respectively .at the inner and outer faces of the posterior wall P. This is for the reason that during the movement of the boring head through the .step S4 the cutters 35 and 36 at the same time are being progressively moved radially further from the axis X, thereby cutting spirals of progressively increasing diameters and producing the tapering out which is best illustrated by theextension linesof=Figure 18.

The .piston stems 55, 66-and 81 are of similar construc-' tion, the details-being.,shown in Figure 24, asectional view of the inotor64. The piston stem consists of an inner tubular. part -88 and am enclosing outertubular part 89, these parts being.connected-to the pistoneGSand to the .supportinglug .68. The part 88 has an-axiahp'assage 90 whichextends between its. endsand is .open to the cylinder space :at the front of the piston, i. e. the cylinder spaceat the rightof the piston, :Figure 24 being-considered'. v The part 8.8 .hasend portions 91 of greater diameter than its .body portion, .-these .being fitted in sealed relation in thepart 89. The reduction in diameter of the body portion of the part-88 provides :a channel 92 of annular cross section.

Theliquid flow paths are the same for theseveral piston stems. Thepassages .90 of the pistonstems .66 and 81 are, connected in each instance externally of the cylinder to a liquidfiow tube 93. The passage 90 of the piston stem is similarly. connected to. a corresponding-liquid flow tube 93. The operating liquidfiows in either direction through thepassages and theconnected-liquid flow-tubes, the flow of the liquid into-thewcylindcr space at either side of the piston effecting the corresponding movement of the cylinder and the flow of theliquid from that space enabling the movement of the cylinder. in the opposite direction. The channels 92of the piston stems 66'and'81 are connected in eachinstance externally of the cylinder to a liquid flow tube 94; Thezchannel 92 of the piston stem 55 is similarly connected: to acorresponding liquid flow. tube 94. The tchannel. :92 communicates with the cylinder space behind the piston .through an opening 95 formed in the part 89. adjacent the piston. The operating liquid flows in eitherdirectionthrough the channels 92 and the connected .liquidflow tubes into the cylinder space at either side .of the piston efiecting a corresponding movement of the cylinder andthe flow 0f the liquid from thatspace enabling themovement of the cylinder in the opposite direction.

The flow of. the liquid is effected by apump of any suitable construction, illustration of which -is deemed unnecessary. The control of the :fiow.-of the-liquid is effected by valves, severally provided in operative relation to the liquid flow tubes connected to each piston-stem.

The manual valve .63, as above pointed out,-controls the flow of the liquidtin relation to .thepiston-stcmSS. :The flow of the..liquid in relation to :the piston stems 66xand 81 is controlled by-automatically operated valves --96 and 96a respectively. Figure 11 shows .the valve96, the valve 96:? being similar inconstruction andoperation. The-valve 36 includes avalvc casing97 and an enclosed valve body 93. The casing 97 and valve-body 98 are preferably of cylindricalform, the va'lve body having a close fit -vithin thechamber of the-casing 97 andbeing slidable between its end walls.

The-valve casingis providedadjacent its-respectiveends with liquid inlet nipples 99' and IOG-andbetWeen these with a liquid return nipple 101. The liquid-supply line s s-seas I (not shown) from the pump is connected to liquid flow pipes (Figure 102 and 103 and the liquid return line (not shown) to the pump is connected to a liquid return pipe 104. The nipples 99 of the valves 96 and 96a com municate with a supply branch 105 (Figure 6) and the nipples 100 similarly communicate with a supply branch 106. The liquidflow pipes 102 and 103 are connected respectively to the branches 105 and 106. The nipples 101 of the valves 96 and 96a are connected by a branch 107 to which the return. pipe 104 is connected. Each valve casing 97 is also provided with nipples 108 and 109 in angular relation to the nipples 99, 100, 101. The liquid flow tubes 93 and 94 are connected to the nipples 108 and 109 respectively. The valve body 93 is formed with circumferential channels 110 and 111. The valve casing 97 is formed with' a longitudinal passage 112 at all times in open communication at an intermediate point with the return nipple 101, the passage 112 having terminal branches 11? and 114 which are open to the inner face of the valve casing chamber. The valve casing 97 is also formed with longitudinal passages115 and 116 which respectively are at alltimes in communication with the nipples 108 and 109.- The passage 115 has terminal branches 117 and 118 and the passage 116 has similar terminal branches 119 and .120, the several terminal branches being open to the inner face of the valve casing chamber. i

The .valve body9 has oper ative left and right positions, Figure ll being considered. The corresponding motor 64 is shown in Figure 24. In its position at the right, as indicated by broken lines in Figure 11, the channel 110'registers with the nipple 100 and the branch 117, and'the channel 111 simultaneouslyregisters with the branches 114 and 119, the valvebody closing the branches 113,113 and the nipple 109 and the branch 120. In this position of the valve body the flow of liquid is through the nipple 100, the channel 110, the branch 117,the.nipple 108 and the pipe 93 and the axial passage 90 ofthe piston stem 66 to the cylinder space in front of the piston 65 whereby pressure is applied to the right end head of the cylinder 67 to move it to the right, Figures Sand 24 beingconsidered. At the same time, the movement of the cylinder 67 to the right thereby being made possible, liquid flows from the cylinder space behind the piston 65 through the opening 95, the channel 92, the tube 94, the nipple 109, the branch 119, the channel 111, the branch 114, the passage 112, the nipple 101 and the return tube 104 to the liquid return line which leads to the low pressure sideof the pump. In the position of the valve body 98 at the left as shown in full lines the channel 111 registers with the nipple 99 and the branch 120 and the channel 110 simultaneously register with the branches 113 and 118, the valve body closing the branches 114 and 119, the nipple 100 and the branch 117; In this position of the valve body the flow of liquid is through the nipple 99, the channel 111, the branch 120, the nipple 109, the tube 94, the channel 92 and the opening 95 to the cylinder space behind the piston 65 whereby pressure is applied to the left end head of the cylinder 67 to move it to the left. At the same time, the movement of the cylinder 67 to the left thereby being made possible, liquid flows from the cylinder space in front of the piston as through the passage 90, the tube 93, the nipple 108, the branch 115, the channel 110, the branch 115, the passage 112, the nipple 101 and the return tube 104 to the liquid return line which leads to the low pressure side of the pump.

The liquid flow circuits of the valve 96a and the associated motor 77 are similar to those of the valve 96 and the associated motor 64.

In the case of the motor 77 the movements of the cylinder 79 to effect the operations of the boring heads are to the right, Figure 5 being considered, and the operating fluid for such movements is delivered through the flow tube 93 and the passage 90 to the cylinder space in i 1 2 front of the piston 78. It is preferable that provision be made for regulating the rate of flow of the operating fiuiduand the flow tube 93 therefore is provided with a shunt 121(Figure' 6) in which is fitted a manually adjust-able regulating valve 122. The tube 93 carries a check valve 123. between the points of connection of the shunt 121 which permits the free retrograde flow of the operating fluid throughthe tube 93 but compels the how of the operating fluid through the shunt 121 in. connection with its delivery to the cylinder space in front of the piston 78. The valve body 93, in addition to the extreme or left and right operative positions which establish the liquid flow circuits above described, has an intermediate or neutral position sufiiciently indicated in Figure 11 by the showing of the channels and 111 in broken lines coincident with transverse planes N. In this position the valve body cuts off the communication with the channels 110 and 111 of the nipples 99, 100, 108 and 109 and the branches 113, 114, 117, 118,119 and and thereby functions as a barrier, rendering the liquid flow circuits inoperative and causing the parts controlled by the particular fluid motor 96 or 96a as the case may be, namely the work unit U and the boring heads10, to remain in the positions to which theyfwere moved in consequence of the immediately preceding operative movement of the valve body. The duration of the valve body in either of its operative positions determines the extent of movement of thecontrolled parts, i. e. the work unit and the boring heads, and its duration in the neutral position determines the periods of restof the controlled parts. Accordingly each valve body 98 is under the control of a suitable governing mechanism to be later'described. Thereby the periods of movements and rest of the controlled parts are coordinated, all as abovedescribed and sufficiently shown in the complementary graphs of Figures 13 and 14.

The manually operated valve 63 for controlling the flow of the operating liquid with respect to the work clamping means, that is to. say through the liquid flow tubes 93 and 9 1, may be of any suitable construction, the

details of one such construction being shown in Figures 25, 26 and 27. As shown in these figures the valve 63 is of the turning plug type and comprises a casing 124 and an enclosedrctatably mounted valve body 125, one of the mounting trunnions of which carries an operating handle 126. The casing 124 is formed with upper and lower nipples 127 and 128 preferablylocated in the central transverse plane and connected to the respective flow tubes 93 and 94'; At its opposite side the casing 124 is formed with nipples 129 and 130 preferably located at opposite sides of the central transverse plane. A liquid supply tube 131 leading from the high pressure side of the pump is connected to the nipple 129 and a liquid return tube 132 leading to the low pressure side of the pump is connected to the nipple 130. The valve body 125 is formed with a passage 133 which is preferably located in a central longitudinalplane and at one end, according to the position of the valve body, directly communicates with either of the nipples 127 or 128, its opposite end communicating at a central point with a peripheral recess 134 which also constitutes a liquid flow passage and is at all times in communication with the nipple 129 to which the supply tube 131 is connected. Since the nipples 127 and 128 are in a centraltransverse plane of the valve casing 124 and the nipple 129 is at: one-side of such plane the passage 133 is laterally inclined as shown in Figure 25. For return flow purposes the valve body 125 is also formed with passages 135, 136 and 137, these being radially directed and in mutual communication at a point along the central axis of the valve body. In one operative position of the valve body as shown in Figure 27 the passage 135 (which extends to the periphery of the valve body) communicates with the nipple 128 and the passage 136 is in a neutral position as shown in broken lines at 136:; in Figure 26. In the second operative position of the valvebody the passage 136 (which also ex-, tends to the periphery ofthe valve body) communicates with the nipple 1127' and the passage 135 is in a neutral position as shown in broken lines at 135a. The passage l37-communicates at a central point with a peripheral recess 138 which also constitutes a liquid flow passage and is at all times in communication with the nipple 130 to which the return tube 132 is connected. Since the nipple 131i is at one side of the transverse plane in which the nipples 1'27 and 128' are located the passages 135, 136 and 137 are in a common plane laterally inclined as shown in Figure in a direction opposite to the inclination of the passage 133.

In Figure 3 it is assumed that the valve body is positioned for the delivery of the operating fluid to the cylinder space below the piston 54, this position being shown in Figures 26 and 27. With the valve body so positioned the operating liquid flows from the pipe 131 through the recess 134, the passage 1'33, nipple 127, tube 93' and passage into the cylinder space below the piston 54, thereby to move the cylinder downward and effect the clamping action. This downward movement of the cylinder is permitted by the escape of the operating liquid from the cylinder space above the piston 54, the return flow of the liquid being through the opening 95, the channel 92, the tube 94, the nipple 128, the passages 1'35 and 137, the recess 138, the nipple and the return tube 132 to the low pressure side of the pump.

Any suitable means may be provided for limiting the movement of the handle 126 into either of the positions required by the vlave body 125. The positions of the valve handle 126 shown respectively in full lines and in broken lines 126a, Figures 2, 26 and 27 may be called clockwise and counterclockwise.

When the cylinder 53 is to be moved to diseangage the clamping elements and permit the removal of the work piece from its carrier the handle 126 is moved to its counterclockwise position. Thereupon the passage 133 is brought into communication with the nipple 128, the passage 136 is brought into communication with the nipple 127 and the passage 135' is brought into its neutral position 135a.

With the valve body so positioned the operating liquid flows from the pipe 131 through the recess 134, the passage 133, nipple 128, tube 94, channel 92 and opening 95 into the cylinder space above the piston 54, thereby to move the cylinder upward with the resultant release of the work unit. This upward movement of the cylinder is permitted by the escape of the operating liquid from the cylinder space below the piston, the return flow of the liquid being through the passage 90, tube 93, nipple 127, passages 136 and 137, passage 138, nipple 130'and return tube 132 to the low pressure side of the pump. When the elements 57 have been sufficiently disengaged consequent to the movement of the handle 126'to its counterclockwise position the work unit U is removed from its carrier 44.

The movementsof the valve bodies 98 of the valves 96 and 96a are preferably effected by double acting solenoids 1'39 and 139a respectively (Figures 6 and 28). Since such solenoids are of well known construction illustration of their details is not} required. It will be sufficient to point out that each includes opposed windings 1 42 and 143 and any usual means for normally holding their armatures 140 in a central'position which is also a neutral position. The armature stems 141 extend through openings in the adjacent heads of the corresponding valve casings9-"l and are connected to the valve bodies. 7

When the boring heads and the work unit are in the relative positions shown in Figure 15 the armatures of both solenoids are in neutral position, these positions being assumed in Figures 6 and 28 In these positions the armatures hold the valve bodies 98 in their neutral positions. The windings 142 and 143 are used toeffect themovem ent of the valve bodies 98 from their neutral 16 positions to their extreme positions at the left and right respectively (Figure 11 being considered). I

The energization of the windings 142 and 143 of the two solenoids is controlled by a cyclically movable governing element which is preferably in the form of a rotatable contact carrying disc 144 (Figures 6, 12 and 28) mounted detachably but in driven relation on the shaft of an electric motor 145, one complete revolution of the element 144 corresponding to a complete cycle of operation of the machine as indicated by the complementary graphs of Figures 13 and 14.

The contact carrying disc 144 is composed of suitable insulating material and is shown in sufficient detail in Figure 12. On one of its flat faces it is provided with contacts for carrying out the steps S1 to S8 illustrated in the graphs of Figures 13 and -14. The contacts are of arcuate forrn and are indicated in their relation to the several steps by the indexletter a, hence being designated as Sla, S211, S3a, S4a, S5a, S611, 87a, and 88a. The movable contacts Sl'a through 88a are severally in cooperation with stationary contacts 146, 147, 148 and 149 located at different distances radially from the. center of the disc 144 and preferably arranged in a radial line. The contacts Sla, 83a and 85a engage the stationary contact 146. The contact S7a engages the stationary contact 147. The contacts S2a andS4a engage the stationary contact 148, and the contacts 86a and 88a engagethe stationary contact 149. Hence the contacts Sla through S8a-are variously arranged along concentric circles which correspond severally in radial location to the radial location of the cooperating stationary contacts.

' The graph ofFigure 14 shows the movements of the work unit, these movements being the steps S1, S3, S5 and S7. The advancing movements of the work unit are effected by the engagement of the movable contacts Sla, 83a, $501 with the stationary contact 146 and the retractile movement of the work unit is efiected by the engagement of the movable contact S7a with the stationary contact 147; The annular extent of each of the contacts Sla, 83a, 85a and 37a determines the period of their engagement with the companion stationary contact and hence dictates the duration of the valve body in the corresponding position and thereby determines the extent of movement of the work unit. When each of the several contacts Sla, S341, 85a and 87a has passed beyond, i. e. disengaged, the stationary contact with which it cooperates the solenoi'd armature is returned by the solenoid mechanism to its neutral position and the work unit remains in the position to which it has been moved for a period dictated by the spacing between the adjacent contacts of the annular series Sla, 33a, 55a and- 57a. In detail: The contactSla effects the movement of the work unit from the position of Figure 15 to the position of Figures 16 and 39 (step S1), the valve body 98 of the valve 96 "being moved. to its operative position at the left, Figure 11 being-"considered, and when the cont-act Sla passes beyond the corresponding stationary contact 146 the armature of the solenoid 139 is shifted back to its neutral position, thereby moving the valve body 98 of the valve 96' back to its neutral position. The work unit remains in its position shown in Figures 16 and 39 for a period correspondingto the spacing of the contacts Sla and 83a and during this period the boring heads 10 are moved through the step S2 (Figure 13). Upon the completion of step S2 of the boring heads the movable contact 83a engages the stationary contact 146 with the result of the work unit being similarly moved through step S3 (Figure 14) to the position shown in Figure 17. When the contact 83a passes beyond the contact 146 the armature oi the solenoid 139 is again shifted back to its neutral position, thereby moving the valve body 98 ,of the valve 96 to its neutral position with the result that the work unit remains in its position shown in Figures 17 and 40 for a period corresponding to the spacing of the contacts 53a and 55a and during this period the boring heads 10 greases 17 are moved through step S4. Upon the completion of the step S4 of the boring heads the movable contact 85 1 engages the stationary contact 146 with the result of the work unit being similarly moved through the step S5 to the position shown in Figures 18 and 41. When the contact 85a passes beyond the contact 146 the armature of the solenoid 139 is again shifted back to its neutral position, thereby moving the valve body 98 of the valve 96 to its neutral position with the result that the work unit remains in its position shown in Figures 18 and 41 for a period corresponding to the spacing of the contacts 85a and S7a and during this period the boring heads 16 are moved through the step S6, their initial retractile step which is from their positions shown in Figures 18 and 41 to their positions shown in Figures 19 and 42. Upon the completion of the step S6 of the boring heads the movable contact S7a engages the stationary contact 147, the valve body 98 of the valve 96 being then moved to its operative position at the right with the result that the work is moved through its retractile step to the position shown in Figure 20. Thereupon the boring heads are moved through the step S8, their final retractile step, to their positions shown in broken lines in Figure 20. The contact 146 is connected by a wire 150 (Figure 28) to the winding 142 of the solenoid 139 and the contact 147 is connected by a wire 151 to the winding 143 of the solenoid 139. The energization of the winding 142 of the solenoid 139 effects the advancing movements of the work unit, that is to say movements to the left through the steps S1, S3 and S5, Figure 5 being considered, and the energization of the winding 143 of the solenoid 139 elfects the retractile movement of the work unit, a movement to the right through the step S7, all as above described. The advancing movements of the boring heads are .to the right,

Figure 5 being considered, and are effected. by the engagement of the movable contacts 82a and 84a with the stationary contact 148 and the retractile movements of the boring head are to the left and are effected by the engagement of the movable contacts 86a and 58a with the stationary contact 149. The energization .of the winding 143 of the solenoid 139a effects the movement of the valve body 98 of the valve 96a to the left (Figure 11 being considered) with resultant advancing movements of the boring heads, that is to say movements to the right and the energization of the winding 142 of the solenoid 139a effects the movements of the valve body 93 of the valve 96a to the left with resultantretractile movements of the boring heads. The contact 148 is connected to the winding 143 of the solenoid 139a by a wire 152 and the contact 149 is connected to the winding 142 of the solenoid 139a by a wire 153. When the several contacts 82a, 84a, 86a and 88a pass beyond their corresponding stationary contacts the mechanism of the solenoid 139a returns the armature to the neutral position with resultant movement of the valve body 98 of the valve 96a to its neutral position, the boring heads thereupon remaining in the positions to which they were previously moved.

The contact carrying disc 144 is provided with a pcripheral contact 154. A current supply line 155 is connected at a neutral point to all of the windings of both solenoids. A current return line 156 has a constant brush contact with the peripheral contact 154 of the carrier 144. The movable contacts Sla through 88a are also connected to the peripheral contact 154 of the carrier144. The circuits for the .energization of the solenoids may be traced as follows with reference to Figure 28: When anyof the movable contacts Sla, 83a and S511 arein engagemcnt with the companion stationary contact 146 the flow of current is from the supply line 155 through the winding .142 of the solenoid 139, the wire 150, the contact 146, the movable contact engaged with thecontact 146, the peripheral contact 154 and the returnline 156. When the movable contact 57a is engaged with the com panion stationary contact 147 the flow of current is from the supply line 155 through the winding 143 of the solenoid 139, the wire 151, the contact 147, the peripheral contact 154 and the return line 156. When either of the movable contacts S20 and S411. is in engagement with the companion stationary contact 148 the flow of current is from the supply line 155 through the winding 143 of the solenoid 139a, the wire 152, the contact 148, the movable contact engaged with the contact 148, the peripheral contact 154 and the return line 156. When either of the movable contacts S61: and 88a is engaged with the companion stationary contact 149 the flow of current is from the supply line 155 through the winding 142 of the solenoid 139a, the wire 153, the contact 149, the movable contact engaged with the contact 149, and the return line 156.

When the step 88a is completed the supply of current to the motor is automatically cut 011. At this time the boring head is in the position relatively to the processed work unit which is shown in broken lines in Figure 20. It is at this stage that the processed work unit is removed and an unprocessed work unit substituted. Thereupon a manual switch is operated to close a circuit for initiating the operation of the motor, the contact disc 144 thereafter establishing the motor operating circuit, the cycle being completed as previously described.

The operating circuit for the motor 145 includes a contact 157 of circular outline mounted on the disc 144 at the side opposite the movable contacts Sla through S80. The contact 157 does not extend through a complete circle but is formed to provide a gap 158 (Figure 12). The contact 157 cooperates with spaced stationary contacts 159 and 160. During the operation of the machine the contact 157 engages both of the stationary contacts as shown schematically in Figure 28. The motor operating circuit includes a feed wire 161 branching from the line wire and connected to one pole. The other pole of the motor is connected by a wire 162 to the stationary contact 159. The stationary contact is connected by a wire 163 to the return line 156. With the machine in operation the motor circuit may be traced as follows: Through the wire 161, the motor, the wire 162, the stationary contact 159, the movable contact 157, the stationary contact 160 and the wire 163 to the return line.

In Figure 12 the direction of rotation of the contact carrier disc 144 is assumed to be counterclockwise as indicated by the arrow and the position of the disc is assumed to be that in which the motor operating circuit has been broken. The contact 159 is so located that when the step S8 has been completed (the contact SSa at such time moving beyond the contact 149) the con tact 157 will immediately thereupon move beyond the stationary contact 159 which will then be in the gap 158 as shown in Figure 12. Thereby the operating circuit for the motor 155 is broken to enable the removal of "the processed work unit and the substitution of an unprocessed unit. When this has been done the motor starting circuit is closed manually. This circuit includes a wire 164 connected to the same pole of the motor as the wire 162 and extending to a stationary contact 165 shown schematically in Figure 28 and which may be of any suitable construction and a manually operated switch 166 held normally open, the other stationary switch contact 167 being connected by a wire 168 to the return line 156. After the unprocessed work unit has been secured in position in the manner previously described the switch 166 is operated manually to close the motor starting circuit through the contacts 165 and 167. This circuit is traced through the wire161, the motor, the wire 164, the stationary switch contact 165, the movable contact of the switch, the stationary switch contact 167, and the return wire 156. The closing of the manual switch 166 re sults in a movement of the contact carrier 144 in which the gap 158 passes beyond the stationary contact 159 at

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