US1310122A

US1310122A - Means for forming tubular articles by extrusion.

Info

Publication number: US1310122A
Application number: US16453517A
Authority: US
Inventors: John W Leighton; Owen J P Crick
Original assignee: PRESSED METALS Ltd
Current assignee: PRESSED METALS Ltd
Priority date: 1917-04-25
Filing date: 1917-04-25
Publication date: 1919-07-15
Anticipated expiration: 1936-07-15

Description

uly 15, 1919. Z SHEETS-SHEET 1- Patented J APPLICATION HLED APR-25.1917.

m mm i J W 7 w m m ym V in. T Q J M w J /\4 v m/l Z @e: M 7)? 2 y w M M 4 Q a x 0 5 k. A|------- 1, 1 4

l. W. LEIGHTON AND O. J. P. CRICK. MEANS FOR FORMING TUBULAR ARTICLES BY EXTRUSION -1. W. LEIGHTON AND O. J. P. CHICK. MEANS FOR FORMING TUBULAR ARTICLES BY EXTRUSION.

APPLICATION FILED APR-25.1911.

Patented July 15, 1919.

2 SHEETS-SHEET 2.

in V6 10m.

JOHN W. LEIG-HTON AND OWEN J". P. CEICK, OF TORONTO, ONTARIEO, CANADA, AS-

SIGNORS TO PRESSED METALS, LIMITED, OF TQRUNTO, ONTARIO, CANADA, A.

oonroas'rion'.

MEANS FOR FORMING TUBULAR ARTICLES BY EXTRUSIQN.

Specification of Letters Patent.

Patented July 15, 1%19.

Application filed April 25, 1917. Serial No. 16%,535.

To all whom it may concern:

Be it known that we, JOHN Wromrrn LEIGHTON and OWEN JOHN Prr'rs CRIGK, both subjects of the King of Great Britain, and residents of the city of Toronto, county of York, Providence of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Means for Forming Tubular Articles by Extrusion, as described in the following specification. and illustrated in the accompanying drawings, that form part of the same.

Many attempts have been made to form tubular metal articles by a process of extrusion from metals which require to be heated to obtain the necessary fluidity but none have been successful for various reasons and it is the principal object of this invention to overcome the difiiculties due to the choking of the tools by the fluid metal and the seizing of the formed articles due to contraction in cooling.

A further object of the present invention is to produce tubular articles of comparatively short length very rapidly by the use of quick operating machines, such as a punch press, requiring the minimum of labor and material, thereby cheapening the cost of production and effecting high quantity production.

A further and important object is to enable the production by extrusion of tubular articles having variations in their diametral dimensions thereby effecting a great saving in material which is extremely important in the making of war munitions for which this invention is primarily adapted.

The principal feature of the invention consists in the novel manner of handling a heated metal billet whereby the metal is forced through the throat of the die around a central mandrel which operates coincident with the plunger and the external and internal dimensions of the produced articles are definitely formed in confinement between the walls of said die and mandrel.

A further important feature of the invenis a vertical sectional View of a plunger and die and the ram of a press used in carrying this invention into effect, the plunger being shown in the raised position.

Fig. 2 is a sectional view similar to Fig. 1 showing the relation of the parts when the plunger is in an intermediate position.

Fig. 3 is a sectional view similar to Figs. 1 and 2 showing the altered relation of the parts in the advanced position at about the completion of the power stroke'of the ram.

Fig. i is an enlarged sectional. View of the plunger and die showing an intermediate and fully advanced position in dotted lines. Fig. 5 is a perspective view of the finished tube.

In carrying the present invention .into effect We utilize a quick operating machine such as a punch press upon the bed of which the die 2 is placed. The die is formed of an upper member 3 having a pocket l therein in which the heated billet from which the article is to be made is placed.

A die block 5 is arranged within the upper member 3 at the bottom of the pocket 4, the

die being of a lesser diameter than saidpocket and having the beveled throat 6 leading from the pocket 4 to the recess 7 which forms the larger upper portion of the tubular article to be made.

A secondary throat 8 is formed in the die block 5 reducing the diameter of the die opening to the size and shape of the eX- ternal diameter of the smaller portion of the tube to be produced. The remaining length of the die is formed by a plurality of die blocks 9 secured in the main die 2. The plunger 10 secured to the ram 11 of the press is adapted to enter the pocket 4- to press the material of the billet into the die and said plunger is provided with a central orifice 12 in which is located the pilot mandrel 13. The former 13 is slida-bly arranged in the plunger and the upper end thereof is formed with a head 14- secured in a cylindrical block 15 slidably arranged within a cylindrical recess 16 axially arranged within the ram of the press and adapted to be reciprocated therein. The upper end of the block 15 is formed with an opening 17 into which the end of the lever 18 projecting through a slot 19 in the side of the ram extends.

The outer end of the lever 18 is carried upon a fixed pivot 20. A fulcrum 21 is secured to the ram beneath the lever 18 and is adapted in the movement of the ram to engage the underside of the lever 18. The lever is held in engagement with the block 15 carrying the mandrel 13 and also in contact with the fulcrum 21 by a coil compression spring 22- encircling the rod 23 pivotally connected to. said lever and slidably extending through a guide 24 arranged on the press.

In the operation of this process the billet 25 which is perforated centrally is first heated to the desired teinperature and is then placed in the pocket 4 and the ram of the press is brought downwardly. As the ram moves downwardly the lever 18 swinging upon its fixed pivot and being fulcrumed on the fulcrum 21 moves the mandrel 13 downwardly at a speed greaterthan that of the punch so as to project from the end of the punch a sufiicient distance to extend through and beyond the bottom of the billet and approximately to the throat 8' just prior to the engagement of the billet by the plunger 10.

The pressure of the plunger 10 flows the material of the billet through the contracted throat 6 into the recess 7 and as the plunger thus moves inwardly into the die the mandrel 13 is advanced by the action of the lever 18 at a speed faster than that of the plunger to and past the secondary throat 8. The block 15 carrying the mandrel 13 then bottoms in the recess 16 and continues to move inwardly with the plunger and projects well intothe restricted portions of the die. The metal flows through the constricted throat 8 to form the reduced portion of the tube and as the mandrel 13 extends well into this restricted portion the metal is thoroughly set to the altered shape before being released from the restriction between the mandrel and the walls of the die. The result of this condition is that the dimensions of the finished tube are accurately determined and a uniform product results.

Immediately upon the cessation of the inward movement of the plunger the pressure is released and the tube immediately con tracts and seizes upon the mandrel 13 and as the plunger is withdrawn in its return movement the tube is partly withdrawn from the die, thereby obviating any tendency.there may be of the tube sticking in the die and avoiding difficulty in releasing.

As the plunger continues its upward movement the fulcrum 21 engages the underside of, the lever 18 and causes the end of the lever engaging the block 15 to move upwardly at a faster speed than the punch consequently lifting the cylindrical block 15' 7 from the die and the plunger.

thereto. The mandrel is thus automatically and forcibly withdrawn from the tubular member formed and consequently releases the tube practically instantaneously, both The operation of forming tubular members in the manner described is extremely rapid, the billets are inserted into the die and the press is tripped and the plunger is brought down with a quick sharp movement. The mandrel is operated to move independently and in advance of the plunger and the material of the billet is extruded into the forming die very rapidly. The downward movement of the mandrel coincident with the flow of the metal effectively prevents the metal being forced upwardly between the mandrel and the plunger, which would cause the mandrel to seize in the plunger and prevent its operation in withdrawing from the finished tube and it also has a beneficial effe'ct upon the grain or texture of the metal and obviates malformation.

The method of operation of the former is herein described as having a movement independent of the plunger in the downward movement thereof, but it mustbe understood that this movement is not essential so long as the mandrel is arranged to project through the billet and into the die and past the throats thereof in advance of the flowing metal, but the independent movement of the mandrel'in the return or withdrawing movement of the plunger is most essential to the success of the operation in order to free the mandrel from the contracted tube.

The confining of the material forming the article between the wall of the die and the mandrel. after passing the throat is extremely important as it maintains the positive dimensions of the article formed in such a manner as to produce positive and definite results.

A further and important feature is the forming of an article of several diameters in a single operation as a comparatively short and heavy billet which will properly hold the required heat may be used and the metal is extruded to form a tube of any desired gage or thickness which may have a heavier portion at one end which will have sufiicient stock for threading or for any other' purpose desired.

- What we claim as our invention is 1. Means for forming tubular articles by extrusion, comprising a die, a plunger adapted to enter the die, and a mandrel arranged in the plunger and adapted to enter the die in advance of the plunger and to be withdrawn from the formed tube in a movement independent of the plunger.

2. Means for forming tubular articles by extrusion, comprising a die, a plunger adapted to enter the die, and a mandrel arranged in the plunger and adapted to be operated to 1% extend into the die in advance of the plunger and to move with. said plunger in the extruding operation and to be withdrawn with said plunger with an accelerating movement faster than the plunger.

{3. Means for forming tubular articles by extrusion, comprisinga die adapted to confine the billet and having a reduced throat through which the metal of the billet is to be extruded, a plunger adapted to enter said die and force the metal through the throat,

. a mandrel slidably arranged in said plunger and adapted to extend through the throat of the die, and means for moving said mandrel coincident withand in advance of said lunger in the extruding operation and wit drawing said mandrel coincident with the plunger with an accelerating move ment to strip the finished tube therefrom.

4. Means, for forming tubular articles by extrusion comprising a die adapted to conto operate said mandrel to withdraw it into the plunger during the return movement of said plunger.

5. Means for forming tubular articles by extrusion, comprising a die having a recess at the top to confine the billet, a reduced portion below said recess and a further reduced portion, a plunger adapted to force the metal into the reduced portions of the die,

and a mandrel adapted to extend through the billet and into the finally reduced portion of the die to form with said die a passage of positive dimensions to receive the extruded metal.

6. Means for forming tubular. articles by extrusion, comprising a die adapted to con fine the billet and having a reduced throat through which the metal'of the billet is to be extruded, a plunger adapted to enter said die and force the metal through the throat, a mandrel slidably arranged in said plunger and adapted to extend through the throat of the die, a lever carried on a fixed pivot and having its free end operatively connected with said mandrel, and a fulcrum member operating with the plunger adapted to engage said lever intermediate of its length to effect the accelerating movement of the mandrel in its downward and upward movements.

' 7. Means for forming tubular articles by extrusion, comprising a die adapted to confine the billet and having a reduced throat through which the metal of the billet is to be extruded, a plunger adapted to enter said die and force the metal through the throat, a mandrel slidably arranged in said plunger and adapted to extend through the throat of the die, a lever carried on a fixed pivot and having its free end operatively con nected with said mandrel, a fulcrum member operating with the plunger adapted to engage said lever intermediate of its length, and a compression spring operating against said lever to hold it in contact with said fulcrum member for the major portion of the downward movement of the plunger.

J. W. LEIGHTON. OW'EN J. P. ORICK.