US2919611A

US2919611A - Cold forming apparatus and method

Info

Publication number: US2919611A
Application number: US526304A
Authority: US
Inventors: Charles A Nichols
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1955-08-03
Filing date: 1955-08-03
Publication date: 1960-01-05
Anticipated expiration: 1977-01-05

Description

Jan. 5, 1960 c. A. NICHOLS 2,919,611

COLD FORMING APPARATUS AND METHOD Filed Aug. 3, 1955 2 Sheets-Sheet 1 INVEN TOR.

% A. 2% HIS ATTOR NE) Jan. 5, 1960 c. A. NICHOLS cow FORMING APPARATUS AND METHOD Filed Aug. 5, 1955 2 Sheets-Sheet 2 H/J' ATTURNE'Y United States Patent COLD FORMING APPARATUS AND METHOD Charles A. Nichols, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 3, 1955, Serial No. 526,304

' 2 Claims. CI. 7838) This invention relates to a metal working apparatus and methods and is particularly concerned with a machine and method for finishing the edges of metal parts such as compressor blades.

It is the main object of the invention to provide a machine and method of operating same wherein a metal object, such as a compressor blade, having a sharp edge or edges thereon may be cold worked to form a rounded edge thereon.

A still further object of the invention is to provide a peening or swaging device which will operate on the edge of a metal part, such as a compressor blade, and which will round oh the sharp corners of the edge and bring the width of the part to a predetermined and desired dimension.

A still further object of the invention is toprovide a machine for peening or swaging the edge or edges of a metal part for providing a radius thereon while simultaneously bringing the width of the part to a predetermined desired dimension which comprises a reciprocating swaging tool driven by a rotatable hammer wherein the amplitude of stroke of the tool is predetermined for swaging the edge e; edges of the metal part to a desired shape and dimension. During rotation of the hammer, the fixure in which the metal part is held may be reciprocated relative to the swaging tool so that the swaging operation is progressively applied along the edge of the part being operated upon.

Further objects and advantages of the present invention will be apparent from the following description, ref erence being had to the accompanying drawings, where in a preferred form of the invention is clearly shown.

In the drawings:

Figure 1 :is a view in perspective of an apparatus suit-- able for rounding the edges of a compressor blade;

Figure 2 is a view partly in section of the apparatus shown in Figure l;

Figure 3 is a view in perspective of a compressor blade prior to the swaging operation;

Figure 4 is a view in perspective of the same blade after the swaging operation;

Figure 5 is a modification of the swaging mechanism wherein a spring return is used on the swaging tool;

Figure 6 is a diagrammatic view of a hydraulic mechanism which may be used to reciprocate the part being swaged; and

Figure 7 is an enlarged sectional view of the blade in the swaging fixture.

It is desirable to finish the edges of metal parts in many instances wherein the part comprises a more or less wire edge or sharp edge which must be rounded off to complete the manufacture of the part. This is accomplished by many expedients such as grinding, machining as in a shaper, etc; Compressor blades such as are used in turbo-compressors, for example, require a high degree of accuracy in their dimensions and it is desirable in such parts to have rounded edges to reduce the resistance to movement in the air and likewise to cause the edges of the blades to be more resistant to erosion. For this reason the edges of compressor blades are preferably rounded and must be operated on in such a manner that a high degree of accuracy in dimension is maintained. This operation in the past has been carried out by precision grinding which is botlrcostly and slow. The present invention is specifically directed to a method and apparatus for rounding the edges of such parts by a simple apparatus which maintains the dimensional tolerances required, while simultaneously carrying out the desired operation at a reduced cost over past methods.

Referring specifically to Figure 1, a swaging or peening apparatus is shown at 20 which includes a base 22 having a pair of slideways 24 mounted thereon in which a vise-like carriage 26 is reciprocally movable. A pair of standards 28 are mounted on the base 22 and support at their upper end a plate 30 which is adjustable upon the standards 28 through the use of adjustment means 32. The plate 30 has an aperture 34 of rectilinear cross section machined therethrough which acts as a bearing and guide for a piston-like element 36. The element 36 carries at its lower end a swaging tool 38 having a groove 40 therein which has the desired conformation for the edge of the part to be swaged. The upper end of the element 36 carries an anvil 42 made of hardened steel. Above the anvil 42 and element 36 is mounted a rotary hammer 44 which comprises a cylinder 46 having mounted therearound in equally spaced relation a plurality of hardened steel hammer members 48 comprising bars set in spaced recesses in the cylinder 46. The bars are held in the cylinder 46 as noted in Figure 2 whereby they are interlocked therein due to the recesses in the cylinder as noted at 50 which are slightly greater than semicircular in cross section so that the bar-like hammer members must be inserted into the recesses 50 from the ends of the cylinder. During rotation of the cylinder 46 these bar-like members 43 may rotate within their recesses 50 for preventing excessive wear thereon. The rotary hammer 44 is carried by a shaft 52 whichis journaled in a bearing 54 carried by the rear portion of the plate 30. The end of the shaft 52 opposite the hammer 44 carries a pulley 56 which is attached by means of a belt 58 to a suitable driving motor (not shown). It is apparent in this instance that in place of the pulley 56 and belt 58 suitable gearing may be utilized to drive the mechanism.

The carriage 26 has an upwardly turned end portion 69 thereon which is attached to one end of a piston 62 of a double acting air cylinder 64. The double acting air cylinder, which will be explained in more detail hereinafter, is adapted to reciprocate the carriage 26 at a suitable speed.

The vise-like carriage 26 is adapted to carry a blade as shown at 76. The blade 70 is wedged in place on the carriage 26 by means of two nylon wedge blocks Y72. and 74 and a steel wedge block 76. The nylon blocks prevent injury to the blade surface. The lower edge of the blade 70 rests in a groove 71 formed in a hardened metal insert '73 set in the carriage 26. The groove 71 is identical in dimension to the groove 40 in the member 38 if the two edges of the blade are to be swaged to the same shape. It is apparent that diflerent cross section grooves may be used to obtain desired results or the two opposed grooves may be diilerent one from the other as desired. The distance between the inner edge of the groove 40 of the swedging tool 38 and the inner edge of the groove 71 of carriage 26 upon which the blade rests is adjusted to the finished dimension of the blade. Thus, as the swaging device or tool 38 hits the blade edge it causes both edges to be swaged simultaneously.

Figure 3 shows a typical cross section of an unfinished blade 70 while Figure 4 shows a cross section of the same blade 70 after swaging. It will be noted that the edges 80 thereon are rounded due to the swaging operation.

In normal practice, during rotation of the hammer 44, the swaging tool 38 and its supporting element 36 will bounce upwardly after each downward pressure stroke of the hammer elements 48 against the anvil. However, in some instances if the speed of the device is varied appreciably from the preferred speeds and if other factors are markedly changed, it may be desirable to utilize a spring as noted at $8 in Figure as a positive return for the element 36. in this case, as the hammer presses the element 36 downwardly the spring 90 is compressed which then returns the element 36 to its upper position after the hammer element 48 has passed.

In practice the hammer 46 is rotated at a speed sufficient to cause the hammer 44 to strike 4-800 strokes per minute on the element 36 which means that the swaging tool 38 hits the edge of the blade 4800 t mes per minute. The speed of the swaging tool 38 is obviously controlled by the speed of rotation of the hammer 44 and the number of hammer elements 48 carried thereby. However, as previously mentioned a speed of 4800 strokes per minute yields very satisfactory results. During the swaging operation, as the swaging tool 33 is being struck at the above noted speed, the carriage 26 is being reciprocated with respect to the swaging tool 33 at a speed of approximately one inch per second so that the edge of the blade is hit approximately 80 times each .0l inch. When the carriage 26 reaches the limit of movement in one direction the cylinder at reverses the direction of movement and causes the carriage to move in the other direction at the same rate of speed. In this manner the swaging of the edge of the blade continues progressively until the edge is rounded as desired and brought to the desired dimension.

During the swaging operation the metal at the edges of the blade is crowded into the cooperating slots until it assumes the contour of the slots. Thus any desired cross section may be formed on the edges or" the blade by this machine and method, wherein opposed edges are to be finished.

While any suitable mechanism may be used for reciprocating the carriage 26, a double acting cylinder as shown at 64 is preferred. in this instance as noted in Figue 6 the cylinder 64 is connected by means of ducts 109 and 192 to a double acting hydraulic valve 1 34 which is in turn connected to a pressure passage 106 and to two relief passages H38 and 119. The back of the carriage 26 has a pair of adjustments 109 thereon which are set to engage a reversing micro-switch 112 which in turn is electrically connected to two solenoids 114 and 116 on opposite ends of a piston 113 of the valve 164. When the switch 112 is in position as shown in Figure 6, solenoid 114 is energ zed and causes the piston Ill?) to be moved to the left as shown which allows fluid under pressure from passage 1% to pass through duct lltltl and cause piston 62 in the cylinder 64 to move to the right and thereby pull the carriage 26 in the same direction. Simultaneously, fluid that was in the cylinder 64 at the right side of the piston is forced through duct W2 and out through passage 103. When the carriage 26 reaches the limit of movement to the right, adjustment 109 engages switch 112 to reverse its position which deenergizes the solenoid 114 and energizes solenoid 116 which will pull the piston 118 to the right thereby permitting fluid under pressure in passage 1% to enter duct 102 and cause the piston 62 in cylinder 64 to move to the left. Simultaneously fluid on the left side of the piston 62 will exhaust through duct 1% and passage Til This action will continue as long as the circuit is ciosed through main switch E18 whereby the carriage 26 will be moved in a reciprocating manner between the limits of its movement as determined by the adjustments 199 on the carriage 26 with respect to the switch 112.

It is apparent that various modifications of this controlling mechanism may be used with equal success, the apparatus shown being exemplary of one form of suitable apparatus.

While the forms of embodiment of the invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. A swaging machine for roundingopposed longitudinal edges of a sheet-like metal part, comprising in combination; a base, a swaging tool support mounted on said base, a swaging tool carried by said support and reciprocable with respect thereto, a fixture associated with said base for holding the sheet-like metal part on edge with one of the longitudinal edges to be rounded exposed longitudinally thereof, a second base in said fixture including a longitudinally extending groove therein which groove has a longitudinal extent at least equal to the length of the part to be swaged and a cross section similar to the ultimately desired cross section of one of the edges to be rounded, clamping means for clamping the part with said one edge in the fixture groove and for preventing transverse deformation of the part while permitting edgewise deformation of the edge portion in the fixture groove, said fixture being so dimensioned that the longitudinal edge of the part opposed to the edge in said groove is exposed longitudinally thereof, a swaging tool support, a swaging tool including a groove therein having a cross section similar to the ultimately desired cross section of the edge of the part and carried by said support and reciprocable therein, means for reciprocating said swaging tool with respect to its support for causing the tool to engage the exposed edge of the part periodically and repeatedly with impact blows and for reacting the opposed edge of the part with impact blows against said base groove, and means for causing relative to and fro movement between the fixture and the swaging tool whereby the swaging tool progressively and repeatedly engages all portions of the exposed edge of the part whereby both edges of the part are rounded.

2. A swaging machine for rounding opposed longitudinal edges of a sheet-like metal part, comprising in combination; a base, a swaging tool support mounted on said base, a swaging tool carried by said support and reciprocable with respect thereto, a fixture associated with said base for holding the sheet-like metal part on edge with one of the longitudinal edges to be rounded exposed longitudinally thereof, a base in said fixture including a longitudinally extending groove therein which groove has a longitudinal extent at least equal to the length of the part to be swaged and a cross section similar to the ultimately desired cross section of one of the edges to be rounded, clamping means for clamping the part with said one edge in the fixture groove and for preventing transverse deformation of the part while permitting edgewise deformation of the edge portion in the fixture groove, said fixture being so dimensioned that the longitudinal edge of the part opposed to the edge in said groove is exposed longitudinally thereof, means for reciprocating said swaging tool with respect to its support for causing the tool to engage the exposed edge of the part periodically and repeatedly with impact blows and for reacting the opposed edge of the part with impact blows against said base groove, a carriage mounted on said base for reciprocally carrying said holding fixture, and means for reciprocating the holding fixture and its carriage to and fro whereby said swaging tool progressively and repeatedly engages all portions of the exposed edge of the part whereby both edge of the part are rounded simultaneously throughout their longitudinal extent.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Kingman Dec. 15, 1874 Smith Oct. 4, 1892 5 Jacobs Feb. 6, 1894 Fenner Dec. 16, 1902 Weston Feb. 25, 1913 Towsend June 10, 1913 Arthur June 26, 1917 lo Brandt et al May 4, 1920 6 Sussman Jan. 22, 1924 Calder Feb. 12, 1924 Dean Mar. 8, 192 7 Lawson June 20, 1933 Cross Sept. 12, 1933 Newall Nov. 5, 1946 Garbe Jan. 22, 1957 FOREIGN PATENTS Great Britain Mar. 11, 1953