US2880780A - Combined stretch and die forming machine - Google Patents

Description

Apnl 7, 1959 H. w. MACKEY COMBINED STRETCH AND DIE FORMING MACHINE 5 Sheets-Sheet 1 Filed Jan. 9, 1957 INVENTOR. H9 71/; 14/ M616 flTTOF/VZ/S April 1959 I H. w. MACKEY 2,880,780

COMBINED STRETCH AND DIE FORMING MACHINE Filed Jan. 9, 1957 5 Shts-Sheet 2 H. w. MACKEY 2,880,780

5 Sheets-Sheet 3 April 7, 1959 COMBINED STRETCH AND DIE FORMING MACHINE Filed Jan. 9, 1957 April 7, 1959 H. w. MACKEY COMBINED STRETCH AND DIE FORMING MACHINE Filed Jan. 9, 1957 5 Sheets -Sheet 4 INVENTOR. 71 M618? April '7, 1959 H. w. MACKEY Y 0,

COMBINED STRETCH AND DIE FORMING MACHINE Filed Jn.

5 Sheets-Sheet 5 V i rrawnur/st COMBINED STRETCH AND DIE FORMING MACIHNE Henry W. Mackey, Detroit, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application January 9, 1957, Serial No. 633,229 7 Claims. (Cl. 15340) The present invention relates to material forming apparatus and has particular reference to metal forming machinery and the like.

In the stretch forming of metals by conventional machines, a side face die is rotatably mounted with one end of a piece of stock anchored thereto. The opposite end of the stock is clampingly engaged independently of the side face die. The assemblage is operable to exert and maintain a predetermined tension on the stock as it is wrapped around the side face die.

A principal object of the present invention is to provide a new and novel mechanism for performing, in combination, stretch forming and die forming.

Another principal object of my invention is to provide an improved device which is capable in one operation of stretch forming a metal blank and die forming the same both longitudinally and transversely.

United States Patent Another object of the invention is to provide a new device of the type described which is particularly characterized by its simplicity and ease of operation.

More particularly, the invention deals with a machine which is provided with a die of irregular contour. This die is pivotally mounted and has a face which takes the contour of the finished part. Another die having a mating cross-sectional configuration is pivotally mounted adjacent the first die. This last mentioned die is straight. The dies are pivotally mounted at spaced pivot locations and are actuated by suitable power means. dies has one end of the work piece fixed thereto while the other end of the work piece is clampingly held and stretched from a location independent from the location where the first mentioned end is held. During the One of the 2,880,780 Patented Apr. 7, 1959 illustrating the position of the machine parts just prior to the insertion of the work piece.

Referring now to the drawings, and particularly Figs. 1 and 2, I have shown my improved combined die and stretch forming device, which includes a base structure generally designated by the numeral 20-. The base structure 20 includes a platform 22, which has a die supporting member 24 pivotally mounted thereon by means of pivot members 26 and 28. The pivot member 26 is secured to the pivot member 28 and to the platform 22 by means of nut and bolt assemblies 30. The die supporting member 24 is secured at its outer periphery to a die 32 in any conventional manner, as for example by welding. It should be noted at this point that the outer peripheral edge of the die supporting member 24, as well as the inner peripheral edge of the die 32 are curved in the form to which the completed work piece is to be formed. It should also be noted that the die 32 in cross section is of an irregular contour so that the work piece may be die formed during the after described operation.

In order to move the die supporting member 24 and die 32 to perform the operation which is hereinafter described, the die supporting member 24, which is pivoted about the pivot pin 29 carried by the pivot members 26 and 28, is operatively connected to power means generally indicated by the numeral 34. The power means 34 includes a fluid pressure or air operated cylinder 36 having a piston 38 (Fig. 4) operatively connected to a piston rod 40. At viewed in Fig. 3, the casing of the cylinder 36 is mounted on the platform 22 through a supporting member 42 and a plate 44 by means of nut and bolt assemblies 46. The supporting member 42 has a rectangular channel 48 disposed therein, which receives a slidable bar 50. The bar 50 extends outwardly from the channel 48 and is provided with a slot 52 which receives an edge of the die supporting member 24 and is pivotally connected thereto by pivot pin 54. The pin 54 also secures a member 56 to the bar 50, the latter threadably receiving one end of the shaft 40.at 58. By this construction, it will be seen that the mounting member 42 and bar 50 act as reinforcing and guiding means for the connection between the power means 34 and the die supporting member 24. It will also be seen that actuation of the power means 34, including the application of fluid or air pressure thereto by suitable operation of the machine the work piece is stretched and Fig. 1 is a plan view of my improved device illustrating the work piece clamped into position just prior to the rolling action.

Fig. 2 is a-sectional view taken on Fig. 1.

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a plan view similar to Fig. 1, illustrating the position of the dies at substantially the end of the cycle of the machine, certain parts being broken away and shown in section for the sake of clarity.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4. Fig. 6 is a sectional view taken on the line 6-6 of the line 22 of connectors (not shown), will cause the shaft 40 to move inwardly or outwardly of the cylinder 36, thereby moving the bar 50 inwardly and outwardly of the channel 48 in the supporting member 42 to thereby move the die supporting member 24 as well as the die 32 either clockwise or counterclockwise. In this aforementioned movement the die supporting member 24 will, of course, pivot about the pivot member 29 located at the left hand end of the die supporting member 24 as viewed in Fig. 1.

In accordance with my invention one end of a work piece 60 is clampingly secured to one end of the die 32. To clamp the work piece there is provided a clamping member 62, which is pivotally mounted at 64 at one end of the die supporting member 24. The clamping member 62 at one end indicated by the numeral 66 is adapted to clampingly engage the work piece 60 and hold it against the die piece 32 while at the opposite end of the clamping member there is pivotally received one end of an output shaft 68 of a cylinder 70. The oppo- 4 site end of the cylinder 70 is pivotally connected at 72 F .1 a P ti r. i l Fi s; a

to a mounting bracket 74 which is fixed to the die supporting member 24. By this construction energization of the cylinder 70 by appropriate connectors (not shown) will cause the shaft 68 to move out offthe cylinder and 3 thereby pivot the clamping member 62 into clamping engagement with the work piece 60.

In order to stretch form and die form the work piece 60, there is also provided on another platform 76, spaced from the first mentioned platform 22, another die supporting member 78 which is pivoted about the pin 80 at a location adjacent the Work clamping member 62. The pivot pin 80 is carried by a supporting structure 82, the latter being secured to the platform 76. The die supporting member 78, which extends lengthwise of the device as shown in Fig. l is provided with a recessed channel 84, which slidably receives a plate 86 therein. The plate 86 is retained in the channel 84 by means of upper and lower retaining strips 80 and 90. The plate 86 has secured thereto a die 92. It will be noted that the plate 86 and the die 92, secured thereto by screws 94, are both straight and are not curved, as for example the die 32 and die supporting member 24. It should also be noted that the die 92, although straight, has a crosssectional configuration so designed when its outer surface tangentially engages the die 32, as shown in Fig. 2 and Fig. 5, it mates therewith. At one end of the platform 76, as shown in Figs. 1, 4, and 7, and in detail in Fig. 5, the die supporting member 78 is pivotally connected by pin 100 to the output shaft 102 of power cylinder 104. The other end of the cylinder 104 is pivotally connected at 106 to an upright support 108, the latter being mounted on an extension of the platform 76. By this construction energization or deenergization of the power cylinder 104 will pivotally move the die supporting member 78 as well as the die 92 and slide 86 about the pivot pin 80.

As more clearly shown in Fig. 4, the opposite end of the work piece 60 from the end which is clampingly held by clamping member 62 is engaged and clampingly held in position by a clamping device generally designated by the numeral 110. The clamping device 110 comprises a fluid pressure or air actuated cylinder 112 which has a piston 114 slidably mounted therein. The piston 114 is connected to an output shaft 116 which extends outwardly of the cylinder and is pivotally connected to one end of a clamping member 118. As shown in Figs. 4 and 6, the clamping mechanism 118 is provided with a base 120 which is slidably mounted on the plate 86. The base 120 is provided with shoulders 122, the latter being surrounded by guide members 124 which form a channel in which the base member 120 of the clamping device may slide relative to the plate 86. The purpose of making the clamping member 110 slidable relative to the plate 86 which carries the die 92 is to enable the mechanism to impart an initial stretch to the work piece 60 before the die forming operation is commenced. The clamping member 118 is pivotally connected to the base 120 at 126 so that energization of the piston 114 within the cylinder will move the engaging portion 128 of the clamping member 118 towards its companion part 130 on the base 120 to clampingly engage and hold the end of the work piece therebetween. The slidable movement of the clamping mechanism 110 relative to the plate 86 is controlled by power means generally indicated by the numeral 132, which is mounted directly in back of the clamping mechanism 110. The power means 132 includes a cylinder 134, which is fixed to the slide 86, and which has a piston 136 movable therein. The piston 136 is provided with piston rod 138, which extends out of the cylinder 134 and is pivotally connected at 140 to the clamping mechanism 110. The cylinder 134 is provided with springs 142 and 144 which are disposed on opposite sides of the piston 136 and serve to maintain the piston in a generally central location of the cylinder when there is no fluid or air pressure affecting the operation of the power means. It will also be noted that the cylinder 134 is provided with connectors 146 and 148 which serve to supply hydraulic medium within the cylinder to move the piston'136 in one direction or the other as desired. This operation will be set forth hereinafter when the operation of the entire mechanism is explained.

It will be noted that when the dies are moved by the respective power means 34 and 104 from the position shown in Fig. l to the position shown in Fig. 4, it is necessary for the die 92 to move a greater distance than the die 32 in view of the fact that the former is straight and the latter is curved. For this reason, it was necessary to mount the die 92 on the slide 86 so that the slide could move relative to the die supporting member 78 during the die forming operation. To illustrate this condition, it will be noted that the slide 86, as viewed in Fig. 4, has moved rightwardly relative to the die supporting member 78, a distance Z. To insure this movement and to insure that the dies 92 and 32 engage the work piece 60 at the same locations during their rolling die-forming action, the die supporting members 32, 92 are provided with gearing means 150 and 152. The gearing means or track 150 is welded, or similarly attached, at the juncture between the die 32 and the die supporting member 24. Similarly the gearing means or track 152 is secured to the slide 86 that carries the die 92. To reiterate, these gearing means 150, 152 insure the interaction between the dies at the same locations every time the rolling, die forming, operation is accomplished. As a result, the gearing action causes the slide 86 to move rightwardly as shown in Fig. 4 to a maximum location as shown at Z.

To insure the return of the slide 86 to its initial position as shown in Figs. 1 and 7, the die supporting member 78 is provided with an upturned abutment 154 which receives a shaft 156 therethrough. One end of the shaft 156 is secured to a member 158, which in turn is fixed to the slide 86 by bolts 160. A spring 162 coacts between the abutment 154 and the member 158 and serves to return the slide 86 to its initial position once the gearing means 158 and 152 have been disengaged by action of the power means 34, 104 on completion of a die-forming operation. An upturned abutment 164 is also provided on the die supporting member 78 and is provided with an adjustment screw 166 to predetermine the return posi tion of the slide 86.

From the following description of the operation of my improved device it will be assumed that the various power means are supplied with hydraulic fluid for their operation, but it should be understood that air pressure could also be used. At the start of a cycle of the operation of the instant device, the mechanism is in the position shown in Fig. 7. Initially a flat strip of metal known as thework piece 60 is inserted into the device so that one end is adjacent the clamping member 62 and the other end is disposed between the portions 128 and 130 of the clamping mechanism 110. At this time hydraulic fluid is permitted to flow to the cylinders 70 and 112 of the clamping devices to thereby clamp the opposite edges of the work piece 60 in position as shown in Fig. 1. Next, fluid pressure is admitted to the cylinder 142 of the power means 132 through the connector 148 to move the piston 136 thereof leftwardly to impart an initial stretch to the work piece 60. The interior portion of cylinder 142 is shown in Fig. 4. Thereafter, fluid pressure is supplied to the cylinder 36 of the power means 34 and to the cylinder 104. It will be found from the manner in which the die supports 24, 78 are moved about their pivot points 29, respectively during a die-forming operation that initially the power exerted by the cylinder 104 is greater than the power exerted by the cylinder 36. This differential pressure causes the die support member 78 to rotate counterclockwise as viewed in the drawings about the pin 80 and the die supporting member 24 to rotate clockwise about the pin 29, the latter being disposed in a slot 29' to accommodate for variations. The slot 29' is necessary to allow for movement of the pin 29 during the machine operation in view ofthe fact that the power means 34 is only pivoted at its die supporting member connection while being fixed at its other end. This rolling action between the die faces continues until the die faces reach a point where the tangent line between the two die surfaces is perpendicular to a line drawn from the pivot pin 29 to the point of contact between the two die faces. At this point, it is necessary to reverse the fluid pressure in the cylinder 36 and to reduce the fluid pressure in the cylinder 104 so that the cylinder 36 takes over and moves the die 32 and die supporting member 24 clockwise to the position shown in Fig. 4.

When the operation has reached the position shown in Fig. 4, the work piece is formed and appropriate pressures are applied to the power cylinders 36 and 104 to return the mechanism to the position shown in Fig. 7, at which point the clamping cylinders release the work piece and it is dropped to the conveyor belt 170, which carries the work piece away from the machine. In this position, as shown in Fig. 7, the device is now ready to receive another work piece and to repeat the operation previously set forth.

It should be noted at this point that the various hydraulic or air operated devices which are employed to operate the cylinders or power means are not shown in detail for the purpose of simplicity since such devices have been known in the art for many years. It should also be noted that the power mechanism 132 is provided with conduits 146 and 148 so that fluid pressure can be fed to both sides of the piston 136 to maintain the desired pressure on the work piece. This will be readily seen in view of the fact that the die forming action may change the pull of the work piece on the power means and it would, therefore, be necessary to vary the position of the piston 136 within the cylinder 134 to maintain the desired pressure on the work piece at all times. It will also be noted that it is more desirable to maintain a differential pressure on the two sides of the piston 136 rather than trying to change the pressure therein by varying the fluid pressure on just one side of the piston 136.

While I have shown one end of the work piece 60 clamped into position and fixed relative to the straight die 92 and the slide 86, it is not unforeseeable that this end' of the'work piece could be clamped into position independently of either of the dies but fixed relative to the base of the machine. By this construction, this independent clamping position may or may not be required to be moved during the machine operation depending on the contour of the completed work piece.

By employing the improved device shown herein, it will be seen that the mechanism performs a dual function in that the work piece is stretched and die-formed in one complete operation, and while I have only shown one form of the invention, it will be understood that various changes could be made without departing from the spirit of the invention.

I claim:

1. A machine adapted to form a work piece to its final contour comprising a base, a first elongated die supporting member, a second elongated die supporting member arranged in side-by-side relationship to said first die supporting member, pivots connecting said members to said base, said pivots being spaced apart from each other in a direction generally endwise of the members, the pivot of said first member being near one end of said first member and the pivot of the second member being near the end of said second member opposite from said one end of said first member, said pivots supporting the members for swinging movement laterally toward and away from each other, first power means connected between said base and said first die supporting member for actuation thereof, second power means connected between said base and said second die supporting member for actuation thereof, said first and second power means yieldably urging said members to swing about their re spective pivots towardeach other, a slide on said first die supporting member and slidable endwise thereof, a die mounted on said slide and extending endwise thereof, a complementary die mounted on said second die supporting member and extending endwise thereof and engageable with and disengageable from said first mentioned die, at least one of said dies having the die forming face of curvilinear shape extending endwise thereof for relatively rolling die forming engagement of the dies with each other progressively from one end toward the other when the dies are pressed together by the power means of the members thus causing said one of the members to swing the other of the members about the pivot of said other of the members, first holding means carried by one of said die supporting members at the end of said one member farthest from its pivot and adapted to secure one end of the work piece, second holding means disposed adjacent the end of the other of said die supporting members farthest from its pivot and adapted to secure the other end of said work piece, and means to control the power applied by said first and second power means to the respective die supporting members to cause the progressive rolling together of the dies from corresponding ends thereof to the other ends.

2. A combined stretch forming and die forming apparatus adapted to form a work piece to its final contour comprising a base, a first elongated die supporting member, a second elongated die supporting member arranged in side-by-side relationship to said first die sup: porting member, pivots connecting said members to said base, said pivots being spaced apart from each other in a direction generally endwise of the members, the pivot of said first member being near one end of said first member and the pivot of the second member being near the end of said second member opposite from said one end of said first member, said pivots supporting the members for swinging movement laterally toward and away from each other, first power means connected between said base and said first die supporting member for actu ation thereof, second power means connected between said base and said second die supporting member for actuation thereof, said first and second power means yieldably urging said members to swing about their respective pivots toward each other, a slide on said first die supporting member and slidable endwise thereof, a die mounted on said slide and extending endwise thereof, a complementary die mounted on said second die supporting member and extending endwise thereof and engageable with and disengageable from said first mentioned die, at least one of said dies having the die forming face of curvilinear shape extending endwise thereof for relatively rolling die forming engagement of the dies with each other progressively from one end toward the other when the dies are pressed together by the power means of one of the members thus causing said one of the members to swing the other of the members about the pivot of said other of the members, first holding means carried by one of said die supporting members at the end of said one member farthest from its pivot and adapted to secure one end of the work piece, second holding means disposed adjacent the end of the other of said die supporting members farthest from its pivot and adapted to secure the other end of said work piece, third power means connected to said second holding means and operable to move said second holding means relative to said slide to stretch said work piece, and means to control the power applied by said first and second power means to the respective die supporting members to cause the progressive rolling together of the dies from corresponding ends thereof to the other ends.

3. A machine adapted to form a work piece to its final contour comprising a base, a first elongated die supporting member, a second elongated die supporting member arranged in side-by-side relationship to said first die supporting member, pivots connecting said members to said base, said pivots being spaced apart from each other in a direction generally endwise of the members, the pivot of said first member being near one end of said first member and the pivot of the second member being near the end of said second member opposite from said one end of said first member, said pivots supporting the members for swinging movement laterally toward and away from each other, first power means connected between said base and said first die supporting member for actuation thereof, second power means connected between said base and said second die supporting member for actuation thereof, said first and second power means yieldably urging said members to swing about their respective pivots toward each other, a slide on said first die supporting member and slidable endwise thereof, a die mounted on said slide and extending endwise thereof, a complementary die mounted on said second die supporting member and extending endwise thereof and engageable with and disengageable from said first mentioned die, at least one of said dies having the die forming face of curvilinear shape extending endwise thereof for relatively rolling die forming engagement of the dies with each other progressively from one end toward the other when the dies are pressed together by the power means of the members thus causing said one of the members to swing the other of the members about the pivot of said other of the members, first holding means carried by one of said die supporting members at the end of said one member farthest from its pivot and adapted to secure one end of the work piece, second holding means disposed adjacent one end of said first die supporting member farthest from its pivot and adapted to secure the other end of said work piece, interacting gear means operatively carried by said slide and said second die supporting member for synchronizing the relative rolling movement of said dies, and means to control the power applied by said first and second power means to the respective die supporting members to cause the progressive rolling together of the dies from corresponding ends thereof to the other ends.

4. A combined stretch forming and die forming apparatus adapted to form a work piece to its final contour comprising a base, a first elongated die supporting member, a second elongated die supporting member arranged in side-by-side relationship to said first die supporting member, pivots connecting said members to said base, said pivots being spaced apart from each other in a direction generally endwise of the members, the pivot of said first member being near one end of said first member and the pivot of the second member being near the end of said second member opposite from said one end of said first member, said pivots supporting the members for swinging movement laterally toward and away from each other, first power means connected between said base and said first die supporting member for actuation thereof, second power means connected between said base and said second die supporting member for actuation thereof, said first and second power means yieldably urging said members to swing about their respective pivots toward each other, a slide on said first die supporting member and slidable endwise thereof, a die mounted on said slide and extending endwise thereof, a complementary die mounted on said second die support ing member and extending endwise thereof and engageable with and disengageable from said first mentioned die, at least one of said dies having the die forming face of curvilinear shape extending endwise thereof for relatively rolling the die forming engagement of the dies with each other progressively from one end toward the other when the dies are pressed together by the power means of the members thus causing said one of the members to swing the other of the members about the pivot of said other of the members, first holding means carried by one of said die supporting members at the end of said one member farthest from its pivot and adapted to secure one end of the Work piece, second holding means disposed adjacent the end of the other of said die supporting members farthest from its pivot and adapted to secure the other end of said work piece, third power means interconnected between said first slide and said second holding means and operable to move said second holding means relative to said first slide to stretch said work piece, interacting gear means operatively carried by said slide and said second die supporting member for synchronizing the relative rolling movement of said dies, and means to control the power applied by said first and second power means to the respective die supporting mem bers to cause the progressive rolling together of the dies from corresponding ends thereof to the other ends.

5. The structure according to claim 3 and further including a return device operatively connected to said slide and operable to return said slide to starting position while the dies are disengaged.

6. A combined stretch forming and die forming apparatus adapted to form a work piece to its final contour comprising a base, a first elongated die supporting member, a second elongated die supporting member arranged in side-by-side relationship to said first die supporting member, pivots connecting said members to said base, said pivots being spaced apart from each other in a direction generally endwise of the members, the pivot of said first member being near one end of said first member and the pivot of the second member being near the end of said second member opposite from said one end of said first member, said pivots supporting the members for swinging movement laterally toward and away from each other, first power means connected between said base and said first die supporting member for actuation thereof, second power means connected between said base and said second die supporting member for actuation thereof, said first and second power means yieldably urging said members to swing about their respective pivots toward each other, a slide on said first die supporting member and slidable endwise thereof, a die mounted on said slide and extending endwise thereof, a complementary die mounted on said second die supporting member and extending endwise thereof and engageable with and disengageable from said first mentioned die, at least one of said dies having the die forming face of curvilinear shape extending endwise thereof for relatively rolling die forming engagement of the dies with each other progressively from one end toward the other when the dies are pressed together by the members with the power means of one of the members causing it to apply a greater turning moment on the other member at the instantaneous line of contact of the dies than the turning moment applied on the other member by the power means of the other member, thus causing said one of the members to swing the other of the members about the pivot of said other of the members against the force of the power means of said other of said members, first holding means carried by said seconddie supporting member at the end of said second member farthest from its pivot and adapted to secure one end of the work piece, second holding means disposed adjacent the end of the other of said die supporting members farthest from its pivot and adapted to secure the other end of said work piece, interacting gear means operatively carried by said slide and said second die supporting member for synchronizing the relative rolling movement of said dies, and means to control the power applied by said first and second power means to the respective die supporting members.

7. A combined stretch forming and die forming apparatus adapted to form a work piece to its final contour comprising a base, a first elongated die supporting member, a second elongated die supporting member arranged in side-by-side relationship to said first die supporting member, pivots connecting said members to said base, said pivots being spaced apart from each other in a direction generally endwise of the members, the pivot of said first'member being near one end of said firstmemher' 9 and the pivot of the second member being near the end of said second member opposite from said one end of said first member, said pivots supporting the members for swinging movement laterally toward and away from each other, first power means connected between said base and said first die supporting member for actuation thereof, second power means connected between said base and said second die supporting member for actuation thereof, said first and second means yieldably urging said members to swing about their respective pivots toward each other, a slide on said first die supporting member and slidable endwise thereof, a die mounted on said first slide and extending endwise thereof, a complementary die mounted on said second die supporting member and extending endwise thereof and engageable with and disengageable from said first mentioned die, at least one of said dies having its die forming face of curvilinear shape extending endwise thereof for relatively rolling die forming engagement of the dies with each other progressively from one end toward the other when the dies are pressed together by the members with the power means of one of the members causing it to apply a greater turning moment on the other member at the instantaneous line of contact of the dies than the turning moment applied on the other member by the power means of the other member, thus causing said one of the members to swing the other of the members about the pivot of said other of the members against the force of the power means of said other of said members, first clamping means carried by said second die supporting member at the end of said second member farthest from its pivot and adapted to clampingly hold one end of the work piece, a second slide mounted on said first slide, second clamping means carried by said second slide adjacent the end of said first die supporting member farthest from its pivot and adapted to clampingly hold the other end of said Work piece, third power means interconnected between said first slide and said second clamping means and operable to move said second clamping means relative to said first slide to stretch said work piece, interacting gear means operatively carried by said first slide and said second die supporting member for synchronizing the relative rolling movement of said dies, and means to control the power applied by said first and second power means to the respective die supporting members.

References Cited in the file of this patent UNITED STATES PATENTS 2,400,151 Kirsch May 14, 1946 2,638,142 Green May 12, 1953 2,713,376 Bath July 19, 1955 2,806,506 Yurka Sept. 17,

FOREIGN PATENTS 27,830 Norway Apr. 16, 1917

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