US2835983A - Apparatus for inspecting mechanical parts - Google Patents

Description

May 27, 1958 A. RAZDQW APPARATUS FOR INSPECTING MECHANICAL PARTS 4 Sheets-Sheet 1 Filed March 28, 1955 IN V EN TOR.

y 1953 A. RAZDOW 2,835,983

APPARATUS FOR INSPECTING MECHANICAL PARTS Filed March 28, 1955 4 Sheets-Sheet 2 IN VEN TOR. BY W W May 27, 1958 A. RAZDOW 2,335,983

APPARATUS FOR INSPECTING MECHANICAL PARTS Filed March 28, 1955 4 Sheets-Sheet 4 IN V EN TOR.

United States Patent 'Ofiice g iififi g APPARATUS FOR INSPECTING MECHANICAL PARTS Adolph Razdow, Montclair, N. J. 7 Application March 28, 1955, Serial No. 497,180

Y 2 Claims. (Cl. 33-'-175) The present invention relates to an apparatus forinspecting of members or mechanical parts in general and a plurality of cross-sections of such members or mechanical parts, as blades and varies of compressors or turbines, in particular.

In applicants copending application Serial Number 426,200, filed April 28, 1954, now Patent No. 2,795,995, an apparatus for and method of controlling or inspecting such members or mechanical parts has been disclosed. This apparatus provides already a workpiece holder for the member or mechanical'part 'as for instance a blade and a plurality of fingers are disposed in a box, which fingers may be advanced in a predetermined plane towards the surface of the blade, and since two series of such fingers are provided spaced apart for a small distn'ce, these fingers form a compartment into which liquid metal is fed to form a cast which reproduces the face of the workpiece, as for instance the blade, in the particularly given plane in which the thus formed compartment is disposed. Optical means are also provided to compare the end face of the formed cast with a reticle or master drawing and upon projection of the end face of the formed cast and of the reticle orof the master drawing on a screen at enlarged scale, any discrepancy between the required cross-section of the blade and the cross-section of the produced blade showing at the front face of the formed cast may easily be detected on the screen.

It must be realized that these blades have to possess twisted surfaces which are accurately calculated according to the laws of flow of the liquid or gaseousfiuids, so as to obtain maximum eificiency from the blading and to prevent turbulence phenomena. These shapes or forms are difficult to design and difficult to-construct in prac tice and the controlling of their production is rather complicated.

Realizing this problem, controlling or inspecting meth- Ods have been devised before, taking point by point the profile of the various transverse sections of the same blade and comparing the results of the measurements point by point with a'theoretical. tracing of the different sections. It is quite apparent that these procedures are very laborious. In order to overcome these difficulties its-has been proposed before to provide an optical arrangement by forming an image of the apparent contour of the various sections of the member to be examined which is projected with magnification to a projection screen. Yet, these methods have not only beenfound' cumbersome, but also insuiiicient for application in all situationswhere particularly complicated profiles had to be inspected.

in applicants copending patent application, Serial No. {182,565, filed ianuary 18, 1955, theabove mentioned apparatus has been further improved by providing a support permitting a vertical as well as a rotary movement thereof, in order to mount the object to be inspected in any desired position, and to provide a box containingtwo series of fingers disposed in two different substantially horizontal planes spaced apart from each other with means for advancing each series of fingers toward the face of the blade to be inspected and also providing means for feeding molten metal into a compartment formed by the face of saidblade, and said ,two series of fingers to form a cast which is then subjected to a comparative optical inspection step by using a theoretical reticle, master drawing or the like for comparison of any discrepancies in the formed surface of the blade. While it is preferable to form a cast between two sets of a plurality of parallel disposed fingers, because such cast may be saved for repeated checking or reference purposes, it has been found that a single set of fingers disposed in a plane upon advancing the same toward the face of the workpiece to be inspected may be retained in the advanced position, so that upon withdrawal of the workpiece an optical inspection of the line formed by the front end of the fingers with a theoretical reticle. or master drawing for initial comparison may be achieved. It is, therefore, one object 'of the present invention to mount the object to be inspected on a support permitting a vertical as well as rotary movement, in order to mount said object in any desired position, and to provide abox containing a single series of fingers disposed in. aplane with manually, mechanically or hydraulically operated means for advancing said fingers toward the faceof the blade to be inspected, so that upon withdrawal' of the object to be inspected, the line formed by the front end of said fingers is then subjected to a comparative optical inspection step by using a theoretical reticle, master drawing or the like for comparison of any discrepancies in the formed surface of said blade.

it is another object of the present invention to provide sharp points at the front end of each of said fingers, in order to bring about a sharp front line formed by the front end of all said figures.

It is still another object of the present invention to provide means for locking said fingers in the advanced position, so that the position of each of said fingers relative to its adjacent fingers may be fixed and any change of the advanced position of any one of the fingers cornpletely avoided.

It is also a further object of the present invention to mount said fingers in an inner box, which inner box is slidably secured in an outer box, the inner box being movable in axial direction of said fingers relative to said outer box, so that upon locking said fingers in the advanced position, the inner box together with said fingers may be removed from the outer box and, thereby, saved as a permanent record of the particular 'crosssection of the object to be inspected and, if found to be correct upon optical inspection, to be used in the capacity of a reticle or the like for future optical'inspection of other blades. This is brought about by inserting another inner box containing said fingers in axial slidable position and ,by optical comparison of the front end of the fingers contained in said other inner box with'the front end of said fingers contained in said first inner box, the latter operating as a reticle in the optical comparison process; It is yet another object of the present invention to cover the object to be inspected with a tape or band of rubberor the like which tape or band is assumed to enter the corners between such adjacent fingers if thesurface of the object to be tested has a sharp inclination.

With these and other objects in view, which will ber comeapparent in the following detailed description, the

- Massa es present invention. will be clearly understood in connection with the accompanying drawings, in which:

'Figure 1 is a plan view of the apparatus for inspecting the cross-section of the workpiece;

* 7 j Fig. 2 is a front elevation thereof;

' Fig.3is an end view thereof;

Fig. 4 is anaxial section through the fingers containa'b xt Fig. is a schematic view indicating theoptical means .for comparison of the frontline of the fingers with a reticleor the like;

-, "Fig. 6 is a fragmentaryl iew of the-front end of the fingers contained in a box with attached locking means; -Fig. 7 is a fragmentary view of another embodiment of the box arrange'rnent;

' Fig. 8 is a tear an view or the hex airangeme 'shown disposed base 1 which :is preferably'equipped'with a circular opening 2 for the purpose, as will be described =later, to projecta light beam towards thefront end of a plurality ofifingers. The base 1 carries two parallel disposed guide members 3 which are adapted to form a guide for ajcarriage14 movable along the base 1 between the guide members 3'. The carriage 4 is adapted to be moved forwardly into. a position in which the opening 2 is cov-.

ered up, in which position a turbine-blade or another workpiecei5is disposed in operative position, namely for engaging the fingers, and which carriage 4 may be withdrawn into inoperative position simultaneously with the workpiece 5 in which the opening 2 is freed to perform the optical testing step of the front end of the fingers.

table6 is preferably of'sector-like shape and permits an 1 in such manner that the bracket-28 may rotate upon the axis of said bushing '27 The bracket 28 is'equipped 41 by-means of the Wheel 42.

a -A turntable 6 is built into the carriage 4, which turnangular displacement relative to the carriage 4 for a few degrees-in each direction by means of'an operating screw 7 A hand-operated screw 8 may be inserted into the carriage 4 in order to lock the latterin any desirable position on the base 1, though it is to be understood that any 7 other. securing means for the carriage 4 may be provided.

The carriage 4has secured thereto and in particular mounted on the turntable 6a bracket-9, which comprises an upright 10 having supporting walls 11. The upright 10 has a projection 12 on which a vise 13 is rotatably mounted upon'a pivot 14,"so that the vise 13 may be adjusted to difierent angular positions and may also be reversedpif necessary for about 180. In order to set thevise 13 into a plurality of predetermined positions, the vise 13 is equipped with 'a-lock'pin 15 which may be inserted into one of a plurality of openings 16 provided on the top face of the projection 12.

The vise 13 "receives two clamping members 17 which 1 The upright, 10 has a vertical rod 19 disposed therein and forms guide faces 20 in which the projection 12 may slide upwardly and downwardly, respectively, by operation of an adjustment screw 21 for the rod 19.- Thus,

the projection 12 together with the vise 13 is mounted for vertical movement in the upright 10, and since the vise -13 is mounted on the projection 12,1 the vise 13 likewise performs this vertical movement. Near the upper end of the member 22 is provided ablock 23 which carries a'slid'e' 24 to the forward end of which is pivotally mounted an abutment member 25- which is adapted to engagethe face of the blade 5 opposite to that which is to be tested. A screw bolt 26 is also provided to adjust the abutment member in proper engaging position with the blade 5, the block 23being rigidly secured to the upright '10. V

{The opening 2 in; the base 1 is equipped with a bush ing 27 and a second bracket 28 is supported by the base with a projection 29 which carries a vertically disposed pin 30. Two bearings 61 are mounted on the base 1 ad-' jacent to the bracket 28 which bearings are adapted to receive a partly threaded rod 32 which upon turning thereof by means of a hand-wheel 33' performs a movement in axial direction. The rod 32 has secured thereto two collarmembers 34 properly spaced apart to receive the,

upper end of the :pin 30, so that upon turning of the rod 32 the bracket 28 performs a rotary movement upon the bushing 27 as pivotal axis. The upper face of the bracket 28 is formed to a dove-tail guide 35 on which a block 36 slides in longitudinal direction upon turn'ing a threaded rod 37 by means of the wheel .38. The block 36 carries a crosswise disposed dove-tail guide 39 on which a second block 40 slides in crosswise direction by'turni'ng the rod The block 40, s-upportsa box 43 containing one series of parallel disposed lingers, as will'be described below.

' It is quite apparent that the present arrangement permits of. adjustment of the box 43 by subjecting the same to a rotary longitudinal and crosswisemovement relative 'tothe base 1.

'In order to permit the measuring of .eachone of the three mentioned adjustment movements, indicator means 44 are provided for reading the rotary movement, indithe'front portion of each of the fingers 48 is appreciably 7 reduced in height and projects through the front end 49 of the body 47, where also packing means 50 arepreferably provided in orderto permit appreciably high pressure in the hollow body 47. The rear face of thecompartment in the hollowbody 47 is set ofi to provide an abutment for the fingers 48 in their rearward movement, while the flange-like formation 51 is provided as abutment means forthe forward movement of the fingers 48. The hollow body 47 is further equipped with an upper-and lower channel 52 which leads to the front of the compartment in the hollow body 47, and a corresponding channel 53 is provided in the hollow body. 47 leading to its rear portion. All four channels '52 and 53 terminate in the rear face 5 4 of the hollow body 47.

A block 55 is secured by means of flanges 56 to the rear end face 57 of the hollow body 47, which block 55 7 contains the channels 58 and 59 starting from the engaging end face of the block 55 in such manner that the channels 52 amount to a continuation of the channels 58 t and 59, respectively, and channel 53 to a continuation of channel 60 in the block 55. The end face 61 of'the block 55 is adaptedfto engage anotherblock (not shown) in which a differential piston (not shown) is mounted for reciprocating movement in the manner disciosed in the copending patent application, Serial No. 482,565, filed January 18, 1955.

By operation of the adjustment screw 21, the vise 13 and, thereby, the bladeS may be raised or lowered toany'desired vertical position relative to the box 43. -The' blade 5 "may thus be divided into a plurality of horizon-. tally disposed zones and by advancing the series of fingers in a plurality of positions of the blade, so that each zone is exactly across the front end'of theseriesof fingers, the

entire face of the blade 5.m'ay be tested for accurate formation by comparing the line formed byrth'e front end of all fingers 48 with a reticle', master drawing, 'or a prethereon a vise-Vernier 62 which may be read relative "to a scale 63 mounted on the upright 10. It is also possible to provide a plurality of vertically spaced apart abutment members (not shown) on the upright to which the vise 13 may be automatically raised successively, in order to arrive at a plurality of zones of the blade 5.

The embodiment of the box 43 shown in Fig. 4 indicates hydraulic means for advancing and withdrawing the fingers 48 in the body 47, since the fingers may be considered as constitutingpistons and the compartment in the body 47 as cylinders, which pistons may be moved in one or the other direction by proper operation of the hydraulic means.

It is to be understood, however, that the fingers may also be advanced manually by pushing their rear ends in forward direction or by electrical means as disclosed in the copending patent application, Serial No. 482,565, filed January 18, 1955.

In order to prevent any dislocation of the fingers 48 after being advanced into the workpiece engaging position, a simplified box 43' is disclosed in Fig. 6 of the drawing, which box has attached to its rear end a bracket 64 which contains bearings for a cam shaft 65 eccentrically mounted on the axles 66. Upon turning the cam shaft 65 clockwise the fingers are freed and may move in axial direction at will. Upon reaching their advanced position, the cam shaft 65 is turned counter-clockwise, thereby engaging the upper face of each of the fingers 48 and locking all fingers by friction against axial movement thereof.

In accordance with the principle disclosed in the copending patent application, Serial No. 482,565, filed January 18, 1955, a cast is to be formed in a chamber formed at least partly by two series of spaced apart arranged fingers. For each zone of the blade to be tested a special cast was required which could be saved and stored for repeated use. In order to permit a series of fingers to replace such cast, a further embodiment is disclosed in Figs. 7 and 8 of the drawing in which an outer box 43 is provided in which an inner box 43 is slidably retained. The inner box 43 is constructed along the lines of the box shown in Fig. 6 and carries also at its rear end face a bracket 64' which has bearings for a cam shaft 65 mounted eccentrically on the axles 66'. The fingers 48 extend through the inner box 43 as well as through the outer box 43*. Upon advancing the fingers 48, the latter may be locked by means of the cam shaft 65' in their advanced position merely by turning the cam shaft 65 counterclockwise. If then the fingers 48 are locked in their position relative to the inner box 43, the latter box may slide out from the outer box 43 and the set fingers 48 may then be stored While locked in the inner box 43 for later use in the same manner as the cast could be stored for the same purpose. In addition, it is also possible to use such properly set series of fingers locked in the inner box 43 to be used in place of the reticle, master drawing, or the like for the optical comparison process as will be set forth below.

If the object to be tested has a very sharply curved face, it is preferred to cover this face with a tape or layer of rubber or other elastic material 67 as disclosed in Fig. 9 of the drawing where a blade is shown having a rubber sleeve. Since the fingers 48 may slightly penetrate the rubber material 67, the triangular empty spaces created between each pair of adjacent fingers 48 are by this arrangement more or less avoided.

It is quite apparent that the advancement of the fingers 48 is merely a preliminary step for the final comparison of the line formed by the front end of all fingers, which line amounts to a reproduction of a section of the face of the workpiece, with a reticle, master drawing, phantom, or the like by optical means.

For this purpose the base 1 carries a housing 68 therebelow which contains a first light source 69, a spherical mirror 70 and condenser lenses 71. The housing 68 is connected to the bottom face of the base 1 by any suitable means and is open at its upper end. Since the housing 68 is just opposite the opening 2 of the base 1 and the optical axis coincides with the longitudinal axis of the workpiece 5, it is possible upon withdrawal of the workpiece 5, by moving the carriage 4 and thus exposing the front end of the fingers 48 to project the latter through a lens having a semitransparent mirror 72, an adjustable projector lens 73 and a mirror 74 onto a screen '75. Focussing means 76 are provided for the projector lens in order to render a sharp picture on the screen 75.

The base 1 has a bracket 77 which carries a second housing 78 containing a second light source 79, a spherical mirror 80, condenser lenses 81, a heat absorbing glass 82 and a reticle holder 83 with focussing adjusting means 84, so that the reticle may be likewise projected over the mirror 72, the projector lens 73 and the mirror 74 onto the screen 75. By comparison of the two projections on the screen 75, the slightest discrepancy between the reticle projection and the casting projection will be disclosed particularly due to the enlargement on the screen.

It is also possible to provide a tracing, print or the like 85 which is subjected to the rays of a light source 86, and then projected onto the screen through the mirror 72, projector lens 73 and mirror 74.

If any discrepancy is found on the screen 75 between the projection of the line formed by the front end of all fingers 48 and that of the reticle or tracing, print or the like, the bracket 28 may be adjusted by rotating, longitudinal or crosswise movement thereof, until the two projections on the screen 75 coincide completely. A reading on the indicator means 44, 45 and 46, respectively, renders the required information for the amount of required rectification on the tested zone of the workpiece 5.

'Instead of adjusting the fingers 48 with the adjustment means provided on the bracket 28, it is also possible to leave the fingers 48 in their position and adjust the reticle until the two projections coincide on the screen 75.

It is quite clear that a testing of a workpiece face requires a division thereof into a plurality of zones and the engagement of a set of fingers in each of the zones, which is then compared, by simultaneous projections with a reticle, phantom tracing, or even a formerly set series of fingers, and the required rectification may then be determined from the turning, longitudinal or crosswise adjustment movement of the bracket 28, that means of the fingers 48, or as a variation of the reticle.

While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. An apparatus for testing a plurality of cross-sections of a workpiece, comprising at least one base, a first bracket mounted on said base, means for moving said first bracket on said base from a predetermined operative position into inoperative position, a second bracket disposed opposite said first bracket, a box mounted on said second bracket, said box comprising a hollow body to form a compartment therein, a plurality of parallel disposed fingers reciprocable in said compartment, said fingers having projections extending beyond said body in operative position and disposed inside said body in in operative position, so that the front end of all said fingers form a line, when in the advanced position, and said line forming a reproduction of a selective cross-section of said workpiece, and fluid pressure means for advancing and withdrawing, respectively, said fingers.

2. An apparatus for testing a plurality of cross-sections of a work piece comprising a box having a compartment therein, said box including an outer sleeve and an inner box slidably received by said sleeve and having an opening therein, and said sleeve having at its front 7 V 97 end a flange to provide an abutment in the forward movement of'said inner box'intdsaid sleeve and defining an opening equal to that of said inner box,'which opening is adaptedto receive-1a plurality of fingers, and one single Cam means secured to said box' transverse to all' said'fingers, and said cam means, in its operative position, detaining said plurality of fingers in its advanced position, so as to permit removal and storage of said plurality of fingers with said inner box from said sleeve for later use. 1

References Cited the file of this patent UNITED SIATESPATENTS 7 Rug'e May 10, Newberg Jan. 20, 1920 Porter June 30, 1931 Duyke Oct. 25, 1955 FOREIGN PATENTS France Apr. 19," 1948

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