US2390828A - Profiling machine - Google Patents

Description

Dec. 11, 1945. E, P. DORMAN 2,390,828

PRQFILING MACHINE Filed May,` 1944 6 Sheets-Sheet 1 In ventorl y l Z [6.7 Attprnegp Dec. 1l, 1945. E. P. DoRMAN 2,390,828

PROFILING MACHINE f3 nu Hf NNN/NWNNNYNA H5 In ventor,

Dec. 11, 1945; E. P. DoRMAN 2,390,828

PROFILING MACHINE I Filed May 5, 1944 6 Sheets-Sheet 3 Dec. ll, 1945.

E. F.` DoRMAN 2,390,828

PROFILING MACHINE 6 Sheets-Sheet 4 Filed May 5', 1944 wahr,

l n verdorl Bur n w .V 2 I 2447* Attorneys Dec l1, 1945- E. P. DORMAN 2,390,828

PROFILING MACHINE Filed May 5, 1944 6 Sheets-Sheet 5 lnveniorI Dec. ll, 1945..

E. P, DORMAN PROFILING MACHINE Filed may 5, 1944 6 Sheets-Sheet 6 Patented Dec. 1l, 1945 PROFILING MACHINE Edgar Philip or to The Dorman, London, England, assign- United Glass Bottle Manufacturers Limited, London, England, a British company Appui-,suon May 5, i944, serial No. 534.325 In Great Britain January?, 1944 7 Claims.

This invention relates to profiling mechanisms or machines and has for its chief object the provision of an improved form of such mechanism which is adapted for simultaneously proilling a number or all of a series of identical forms regularly recurring upon or in a body. particularly a body of circular form or cross section.

The invention is particularly applicable to the profiling of such articles as rotary impellers.

The impellers that form a part of superchargers and the like, associated with the power units of aircraft, while varying considerably in form, being in some cases double-sided, and in other cases single-sided, all comprise a regularly spaced recurrent circular series of vanes, alternating with gas passages.

Such impellers revolve at very high speeds, involving physical stresses that can be met only by the use of materials of high tensile strength produced in a forged condition. Also, on account of aerodynamic and physical considerations, they must, necessarily be very accurately formed.

It is generally convenient therefore to forge a blank to the approximate exterior dimensions of the impeller, which is then turned to its true outside form, and afterwards to cut from the solid the material representing the gas passages, leaving radial vanes projecting from the flange or boss from which they spring.

In some instances, the whole of each of such radially disposed vanes, as viewed in cross section, is parallel with the axis of rotation of the impeller, but, in other instances, a part only of each of such radial vanes, as viewed in cross section, is parallel with this axis, other parts of the vane, while remaining radial, as viewed axially, may be progressively inclined, as viewed in cross section, from a condition in which they are parallel with the axis of rotation, to that in which they are approximately helical to that axis.

Vanes of the latter character oier peculiar difculties to forming from a solid blank, and, to avoid this difilculty, such vanes are sometimes first formed by machining to the simpler form in which they are wholly radial and parallel with the axis of rotation, and later a part of each such vane is bent or formed to an approximately helical form. The vane thus produced is an approximation only to the correct form, and is further objectionable in being eccentrically loaded under the action of centrifugal force.

In the known methods of machining the aforesaid gas passages and vanes to their correct form, the process known to the art as profile milling is used, and, for this process, it has been customary hitherto to provide a master form, representing one gas passage and one side each of two contiguous vanes, and from this master form, to prole mill the gas passages one at a time in the impeller.

As there are commonly a considerable number of gas passages and vanes to be cut in each impeller, and, as only one tool is operating at a time, and may, of necessity, be of slender proportions prescribed by the form of the work, the process is a most tedious and costly one.

The chief object of the present invention is to provide an improved method of performing such operations, and an improved machine for putting such method into eiiect, by which the time required for carrying out such profiling operations may be greatly reduced.

A further object of this invention is to provide an improved form of machine or mechanism which when used in conn'ection with the profiling of such objects as rotary impellers will ensure that all vanes and gas passages, so cut or formed, are exactly uniform, and that distortion of the work, due to internal stress, that may result from cutting only one vane or gas passage at a time will be avoided. Another object of the invention is to provide a method of operating that enables cutting tools of more rigid form to be employed. Another object of the invention is to provide an improved form of machine or mechanism that can be operated by semi-skilled labour.

The invention consists in a mechanism or machine for simultaneously proling a number or all of a series of identical forms regularly recurring upon or in a body, particularly a body of circular form or cross section, comprising means or a centrally disposed member adapted to support the work and a master-form, having the form, shape or conilguration of one of the forms or passages to be produced, in fixed mutual relationship and so that they are capable of movement together relatively to an annular series oi rotary cutting tools arranged around the work with their axes disposed radially or substantially radially there According to another feature of the invention the rotary cutting tools are mounted and arranged so as to be capable of being moved axially and towards or away from the centre of the work, the arrangement being such that the cutting tools or their mountings are interconnected and adapted to be displaced simultaneously and identically.

According to a further feature of the invention, a tracer is provided for co-operation with mounted in fixed mutual relationship and common axial alignment upon a centrally disposed supporting member, whose axis may conveniently be vertical, adapted to be raised and lowered axially and revolved alternately in either direction. In combination with the above, is a plurality of rotary end cutting tools, adapted to coact upon the work, there being one tool provided for each gas passage to be cut in the impeller, said tools being arranged in a uniformly spaced circular series, the axes of each tool being horizontal, as viewed in one plane. and truly radial with regard -to the work supporting member, as viewed in another plane, the wholer o1' the plurality of rotary end cutting tools being adapted to be simultaneously and uniformly displaced axially toward and away from the centre of the work, a tracer member adapted to co-operate with the master form, mounted upon or coacting with one of the plurality of tool supporting members, adapted conversely, in co-operation with the master form, to control the movements of all the plurality of end cutting tools.

With such an arrangement, since all of the plurality of cutting tools will be adapted to operate upon the work simultaneously, all oi' the vanes and gas passages will be in process of being formed at one and the same time, and the time required, therefore, to complete the forming of the whole of them may thereby well be reduced approximately to the time at present required to cut one of the gas passages.l together with one side each of two contiguous vanes.

Also. since all of the tools are controlled from a single source, i. e, from the single tracer cooperating with the master form, it follows that, if all the tools are identical and are equally set and spaced in the first instance and, if the movements of all are transmitted to them from the tracer co-operating with the master form by identical positive means, the paths traced out by each of the plurality of tools will be identical, andby corollary the forms cut or formed in or upon the work by the plurality of cutting tools will be identical one with another and with the form of the master.

It will be appreciated that this feature is of great importance in work of the nature here considered where not only slight variations as between one gas passage and another are objectionable, but. of more immediate importance, the resultant variation in vane thickness may, by affecting the dynamic balance of the impeller at extremely high speeds, have disastrous eiiects upon the bearings.

In the embodiment of the machine to be described, the movements of the work supporting member, both axial and oscillatory, and the axial displacement of the cutting tools toward and away from the work, will be my manual means, but it is expressly to be understood that a machine, functioning as will be described, is particularly adapted to be operated by electric or hydraulic power, the movements of the various parts vprojecting bolt, E.2. Upon EJ, the blank or work-piece EJ rests, being censodass being automatically controlled by what is known to the art as an electric tracer, which co-operates with the master form, such. i'or instance, as is described in British patent speciilcation 818,587, July 31, 1930, Keller, et alia.

' In order that the said invention may be clearly understood and readily carried into eiiect, the same will now be described more fully with reference to the accompanying drawings, in which- Figs. 1A and 1B showV a sectional elevation of one form of machine produced in accordance with the invention;

Fig. 2 is a part section plan view along certain levels of the machine shown in Figs. 1A and 1B, the part extending from the radial line O-I to the radial line O-II being a part plan view, the part extending from radial line O-II toradial line O III being a section at line A-A in Figs. 1A and 1B, and the part extending from radial line O-III to radial line OX being a section at line Bi-B in Figs. 1A and 1 Fig.' 3 is a similar part sectional plan view of the machine at the part extending between radial lines O-IV and OY being a section at line C-C in Figs. 1A and 1B, and the part extending between lines OX and O-IV being a section at line B-B in Figs. 1A and 1B;

Fig. 4 is a part view of the machine in elevation showing the tracer support, and tool shafts adapted to be driven by anvendless belt;

Figs. 5, 6 and 7 are part views of the machine both in plan and part full and part sectional elevation, showing a tool shaft adapted to be driven by an individual electric motor, and

Fig. 8 is an enlarged sectional elevation of a part of the work supporting member.

The machine shown in Figs. 1A andglB of the accompanying drawings comprises a frame A of annular form having at its lower end, a continuous foot A.| suitable for attachment either to the floor, or to an iron base, and at its upper end, an interrupted anged member A.2. Projecting inwardly from the annular frame and towards the centre of the frame, are two annular shelves, B.i and B.2, whichsupport respectively an upper bearing CJ and a lower bearing C.2.

`A cylindrical member D is arranged so as to be capable of being oscillated and for axial slid-i ing movement within these two bearings. At it upper end, the member D terminates in an ex terpal flange D.I and, at its lower end, in an internal flange D.2.

Bolted to the flange D.| is another flange member EJ, to which is attached rigidly an upwardly this flange member tred by a spigot E.8 which is formed upon it and which enters and fits within a vrecess formed for the purpose in the flange member EJ.

Through and from the member E.|, dowels E.3 project into the work EJ to ensure that the work EJ and the member E.I remain in constant relation together. At the upper end of the work EJ a. flange EA is similarly dowelled to the work at E.5.

A nut E B upon the end of the bolt E.2, holds the flange EA, the work EJ, and the flanged member E.I securely together. Resting upon the flange EJ, is the master form F.i, which containvs the counterpart F.3 of one of the plurality of cavities to be cut in or upon the work, said master form being flanged at its lower end for attachment by bolts to the ange EA. and, at

its upper end, for attachment by Ibolts to an upward extension F1 suitably iianged at its lower end for the purpose.

Extending upwardly from the frame A are suitable supports R, R, which, at their upward extremities, are so formed as to be adapted to support rigidly an outboard bearing member R..I, formed at the axis of the machine as a bearing RJ, adapted to support and guide for axial and rotational displacement the extension F.2 of the master form FJ.

The exterior or peripheral surface of the flange D.I is threaded (see also Fig. 8) and there is mounted thereon a suitably internally threaded ring D.3, which ilts freely upon it, being provided at its upper end with a ring or gasket of rubber or other resilient material, to which reference will be made hereinafter.

The cylindrical portion of part D is splined externally (see Fig. 3) to mate with a wormwheel G, suitably internally splined to receive it. This wormwheel is constrained against axial displacement by a housing G.I and is controlled for rotation by a worm G.2, mounted on a shaft G3,

- adapted to be operated by a handwheel, GA.- The member D is adapted to be raised or lowered axially by the screw H, tc which it is rotatably attached, working in a nut HJ, which is formed exteriorly as a screw gear. A shaft H.3 which is adapted to be operated by handwheel HA is in geared connection with the geared nut HJ. The screw H, geared nut HJ, and gear connection, are all contained within a downward extension consisting of parts C 3, 0.4 and 0.5 depending from the lower bearing C.2, the screw H being prevented from rotating by keys H.5, which form a part of the downward extension 0.5.

Upon an upwardly extending part of the bearing C.| a wheel J is freely journalled, being constrained against axial displacement by ilange J i, and a part of the bearing C.I. Also, upon a part of the outer rim of 'this wheel J, are formed teeth J.2, suitable for engagement by a Worm JA, and, up'on another part of the rim, -bevel gear teeth J.3- are cut. The worm JA is mounted on a shaft J.5, adapted to be operated by a handwheel J .6. Meshing with the bevel gear teeth, J.3, is a circular series of bevelled pinons, K. K. K., etc., axially disposed at equal intervals around the centre of the machine, there being one for each tool head. Each of these bevel gears is mounted within a bearing K.l, attached to the frame A and keyed to an outwardly extending spindle K.2, which is threaded for a part of its length.

Within the interruptions already referred to in the upper flange A.2 are formed equally spaced slideways A.3, radially disposed as regards the centre of the machine and within such slideways is mounted a series of bearing members L. L. L., etc., each formed with a downwardly projecting member L I, terminating in an internally threaded boss, adapted to engage the screwed thread formed on one of the spindles K1. Each of these bearings L is bored so as to house a spindle L.2, which is free to rotate within it, but is constrained as regards axial movement by the flange L.3, and a tool holder LA. At its inner end, the spindle formed as a tool holder at LA, mounts the cutting tool L.5, hile, at its outer end, it is extended in the form of a splined shaft L.6.

A pulley M.|, journalled within a bearing M, attached to the frame A, is internally splined to mate with the shaft L.6, and is adapted to allow the shaft L.6 to slide freely through it, while ensuring that pulley and shaft rotate together.

From one of the series of bearings L, an upwardlyprojecting member N supports, so as to be vertically adjustable, a housing N.l, in which is mounted, so as to be axially adjustable, a tracer member N.2.

For the purpose of driving the tool spindles L.2 through their pulleys M, the following method 'may be adopted. Toward the lower end of the frame A, a ypulley P is mounted upon the outer end of a shaft P.|, which is supported within a bearing P 2, attached to the frame A, and upon the inner end of this shaft is mounted the spur gear wheel P.3, which may conveniently mesh with a pinion mounted upon the armature shaft of an electric motor, not shown. At intervals around the lower part of the frame A is mounted a series of loose pulley, Q. Q. Q., etc. A continuous belt PA passes around the underside of the driving pulley P, up and over one .of the pulleys M, down and under the first of the loose pulleys Q, up and over the next pulley M, etc., etc.

Alternatively, each tool spindle may be independently driven by :m individual electric motor S (see Figs. 5, 6 and '7), mounted upon a quill SJ, housed slldeably within a bearing S.2, which is attached to the flange A.2, formed upon the upper extremity of the frame A. In such case, the armature of the motor may be mounted directly upon an extension S of the tool spindle 8.9, which is adapted to rotate within the quill SJ, being constrained from axial movement relative to the latter by the tool holder S." and by a collar S.8 attached to the tool spindle S.9, which co-operatively engage the ends of the quill SJ. The quill S.I is prevented from rotating within its bearing S1 by a part S4, which. projects downwardly, so as to fit freely between the sides of an axial aperture S10, formed in the base of bearing S.2, and terminating in an internally threaded boss S.5, adapted to co-operate with one of the threaded spindles K1.

The combined weights of parts F.I and F1, EJ, E.2, EA, E5, D and H, as well as all parts attaching to them that are adapted to be together raised or lowered axially, are carefully counterbalanced by means such as a chain or wire rope T, attaching to the upper end of extension F.2, which passes upwardly and over a pulley T.l, attached to an overhead support, not shown, thence laterally over another pulley, T.2, and) downwardly to support a suitable weight. l

The operation of the manually controlled ma' chine described above is as follows:

A turned blank EJ, in which the fins and gas passages lmay have been roughly preformed, is set in position on the flange member EJ, the dowels EL3 are introduced into both, to prevent relative angular movement, and the flange EA, placed in position above the Work. The dowels E.5 are now introduced through flange EA, into the upper end of the work EJ, and the nut E.6 is tightened down, so as to bind together the flange E 4, the work EJ, and the work support flange E I. The master form F.|, together with extension F.2, to which it is bolted, is now set in position upon flange EA, and bolted to it, fitted bolts and/or dowels being provided to prevent relative movement between these two parts.

All the foregoing assembly work may conveniently have been carried out remote from the machine, and, when completed, the assembled parts are together placed in position in the machine, the flange E.I being centred by and resting upon the upper flanged portion D.I of the Work support D. Fitting bolts and/ or dowels are now introduced through the flange D.I, into the flange EJ, securely binding the two together against relative angular movement.

I'he outboard support member RJ is now placed in position upon its supporting members R. R., the central bearing R.2 surrounding and supporting the extension F.2, and the nuts tightened down on the supporting members R. R.

The internally threaded ring D.3 is now revolved in an appropriate direction upon the threaded exterior of ange D.I, until the ring or gasket of suitably resilient material DA with which the upper face of ring D.3 is `provided engages all around on a circular zone, the under side of the work EJ near its periphery and the ring is screwed home so as slightly to compress the material of the gasket D.4. This device has l for its function to damp out vibration set up by the action of the cutting tools, acting upon the thinner sections of the work near its circumference, which, unless checked, tend to become aggravated, ultimately affecting the rotational speed at which the cutters may be run, and the depth of cut and rate of feed that would otherwise be possible.

The tools L 5 having been set in the holders L.6, care having been taken that their extremities are all at a uniform distance from the centre of the work, the extremity of the tracer member N.2 is now set in the housing N.I vat an equal distance from the centre of the master form, and the'housing N.I adjusted upon the upward extension N from one of the bearings L, until the axis of tracer N.2 is separated vertically from the axes of the tools L.5 by the same distance as master form F.I and work EJ are set one from another.

Power having beenapplied to rotate the plurality of tools, the operative may now, by appropriate rotation of thehandwheels HA and GA, respectively raise or lower and rotate clockwise or anticlockwise the work E." and master form F.I upon the support D, until the form F.3 upon the master form F.I, which is to be cut in plurality in the work EJ, presents in a desired aspect to the tracer N.2.

By appropriate rotation of handwheel .1.6, the operative may now advance all of the tools L.5 until they are in positions to operate upon the work EJ, and he may then further advance them until they commence to cut, and may now rotate the work and master upon the support D, by means of handwheel J .6, the plurality of tools all operating upon the work simultaneously. Further rotation in that direction of work and master is ultimately prevented by a part of the form F3 coming in contact with the tracer member N.2.

The operative may now raise or lower the work support D by appropriate operation of the handwheel HA, and advance the tools with relation to the centre of the work, and may then rotate work and master form in the opposite direction, so that the tools all recommence operating upon the work.

By alternatively raising or lowering the work and the master form, advancing or withdrawing the tools and the tracer with relation to the centre of the work and the master form, and alternately rotating the work and the master form in either direction, it is possible to cause the tracer to engage and traverse every part of the master form, all of the tools meanwhile following exactly the same paths upon the work.

It is immaterial whether the relative movements of the tools and the work represent a succession of radial, or of circumferential, or of vertical passes over the work, or whether a combination of any two or all oi these is adopted, but a convenient method will be to cause the tools to.

cut radially inwardly of the work, then to change direction, so as to cut circumferentially of the work. then again to change direction, so 'asto cut radially outward of the work, and continually to repeat this process.

I claim:

1. Mechanism for simultaneously proiiling a series of identical forms regularly recurring around the surface of a body, comprising a centrally disposed member supporting for axial and oscillatory movement together and in spaced relationship the work-piece and a master form, which master form corresponds in shape and connguration with the shape and configuration of one of the forms to be reproduced in plurality in the work-piece, an annular series of rotary cutting tools arranged around the work-piece with their axes disposed substantially radially thereto, and a tracer cooperating with said master form and means for producing relative movement between the annular series of tools and the member supporting the work and the master form, the said tracer serving to determine the common figure cut simultaneously by all of the rotary cutting tools by limiting both oscillatory and axial displacement of the work support and the axial displacement of the cutting tools as they move towards the center of the work-piece.

2. Mechanism for simultaneously profiling a series of identical forms regularly recurring around the surface of a body, comprising a centrally disposed member supporting for axial and oscillatory movement together and in spaced relationship the work-piece and a master form, which master form corresponds in shape and coniiguration with the shape and configuration of one of the'forms to be reproduced in plurality in the work-piece, an annular series of rotary cutting tools arranged around the work-piece with their axes disposed substantially radially thereto, a tracer cooperating with said master form and means for producing relative movement between the annular series of tools and the memberv supporting the work and the master form, the said tracer serving to determine the common ligure cut simultaneously by all of the rotary cutting tools by limiting both oscillatory and axial displacement of the work support and the axial displacement of the cutting tools as they move towards the center oi the work-piece, a shaft extending from each cutting tool, bearing slides for supporting each shaft for rotary and axial movement, a slideway iixed in the mechanism within which slideway said bearing slide is housed, and means interconnecting said bearing slides whereby movement of one oi' them is transmitted to and exactly reproduced in all of said bearing slides.

3. Mechanism for simultaneously proiiling a series of identical `forms regularly recurring around the surface of a body, comprising a centrally disposed member supporting for axial and oscillatory movement together and in spaced relationship the work-piece and a master form, which master i'orm corresponds in shape and configuration wth the shape and configuration of one of the forms to be reproduced in plurality in the work-piece, an annular series of rotary cutting tools arranged around the work-piece with their axes disposed substantially radially thereto, a tracer cooperating with said master form and means for producing relative movemen-t between the annular series of tools and the member supporting the work and the master form, the

- movement of one of them is transmitted to and exactly reproduced in all of said bearing slides, and rotary means common to all of said bearing slides for imparting axial movement thereto.

4. A mechanism as claimed in claim 1 wherein the Work is mounted in position on a, vertically disposed work-supporting-spindle, the master-form is spaced from the work in axial alignment and in xed mutual relationship therewith and means is provided for raising or loweriner the said spindle and for displacing the same angularly in either direction so that the work and the master form move in unison and maintain their xed relationship at all times.

5. A mechanism as claimed in claim 1 in which each cutting tool is carried by a shaft which forms an outwardly projecting axial extension of -the cutting tool, and comprising means for supporting each tool shaft for both rotary and axial movement.

6. A mechanism as claimed in claim 2 wherein one of the said slides is formed with an extension or projecting member having securely but adjustably mounted therein the tracer for engaging the master-form.

7. A mechanism as claimed in claim 1 in which the work-supporting-spindle is provided with an adjustable ring having a facingof resilient Inaterial for bearing around the work at its periphery in order to damp out vibration effects.

EDGAR PHILIP DORMAN.

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