US3881340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drawing machine
Assignee: Marshall Richards Barcro Ltd
•
Filing: 1972-11-22
•
Granted: 1975-05-06
•
Expires: 1992-11-22
Abstract
Abstract An improved method and apparatus for reducing the diameter and/or the wall thickness of metal tubing by generating sufficient tension in a length of tubing downstream of a reducing die to draw the tubing through the die is characterised in that the drafting tension is created by frictionally engaging the tubing in an endless groove defined by two converging surfaces and moving the surfaces and die apart at the desired drawing speed.
Inventors
- 👤 Robert Thomas Vernon Hay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:15
CPC Classifications
B; B21; B21C; B21C47/00; B21C47/02; B21C47/10; B21C47/14; B21C1/00; B21C1/02; B21C1/14; B65; B65H; B65H51/00; B65H51/02; B65H51/04; B65H51/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
127 words
A method of reducing the diameter and/or the wall thickness of metal tubing by generating sufficient tension in a length of tubing downstream of a reducing die to draw the tubing through the die, characterized in that the tension is created by urging the tubing into a convex groove section of an endless groove defined by two converging relatively acutely inclined wedging surfaces to releasably wedge the metal tubing therebetween with a sufficient radial force substantially less than and established independently of the drawing tension to prevent relative slip between the tubing and the wedging surfaces when the endless groove and the die are relatively moved at the desired drawing speed and relatively moving the die and endless groove to draw the metal tubing through the die.
Claim 2
Independent Claim
127 words
A method of reducing the diameter and/or the wall thickness of metal tubing by generating sufficient tension in a length of tubing downstream of a reducing die to draw the tubing through the die, characterized in that the tension is created by urging the tubing into a convex groove section of an endless groove defined by two converging relatively acutely inclined wedging surfaces to releasably wedge the metal tubing therebetween with a sufficient radial force substantially less than and established independently of the drawing tension to prevent relative slip between the tubing and the wedging surfaces when the endless groove and the die are relatively moved at the desired drawing speed and relatively moving the die and endless groove to draw the metal tubing through the die.
Claim 3
Dependent Claim
22 words
A method as claimed in claim 1, in which the groove is defined in the peripheral surface of a cylindrical drawing block.
Claim 4
Dependent Claim
27 words
A method as claimed in claim 2, in which the groove is provided by converging surfaces defining an included angle in the range between 12* and 25*.
Claim 5
Dependent Claim
35 words
A method as claimed in claim 2, in which the tubing is retained in the groove over a circumferential distance around the block of at least 180* as subtended at the centre of the block.
Claim 6
Dependent Claim
128 words
A tube drawing machine comprising a support for tubing to be drawn, a die holder, a drawing die mounted on the die holder, means for collecting tubing drawn through the drawing die in the holder, a drawing block rotatable about an axis, the block havIng an endless peripheral annular groove formed therein defined by two annular wedging surfaces converging at an acute angle, in the direction towards the rotational axis of the block, to a meeting plane which is normal to said axis, for wedging the tubing therebetween, means to rotate the drawing block and means separate from the tubing and operable independently of the drawing tension to hold tubing passing through the die in less than 360* of the groove in frictional engagement with said wedging surfaces.
Claim 7
Dependent Claim
128 words
A tube drawing machine comprising a support for tubing to be drawn, a die holder, a drawing die mounted on the die holder, means for collecting tubing drawn through the drawing die in the holder, a drawing block rotatable about an axis, the block havIng an endless peripheral annular groove formed therein defined by two annular wedging surfaces converging at an acute angle, in the direction towards the rotational axis of the block, to a meeting plane which is normal to said axis, for wedging the tubing therebetween, means to rotate the drawing block and means separate from the tubing and operable independently of the drawing tension to hold tubing passing through the die in less than 360* of the groove in frictional engagement with said wedging surfaces.
Claim 8
Dependent Claim
42 words
A tube drawing machine as claimed in claim 5, in which the groove is V-shaped and, in any cross-section in the radial direction of the block is defined by converging straight lines, the angle between the lines being between 12* and 25*.
Claim 9
Dependent Claim
42 words
A tube drawing machine as claimed in claim 6, in which the upper of the two surfaces lies in the meeting plane, the lower surface being a frusto-conical surface inclined upwardly to define a groove of internal angle between 17* and 22*.
Claim 10
Dependent Claim
24 words
A tube drawing machine as claimed in claim 5, in which a flexible endless belt is used to hold the tubing in the groove.
Claim 11
Dependent Claim
24 words
A tube drawing machine as claimed in claim 5, in which at least one roller is used to hold the tubing in the groove.
Claim 12
Dependent Claim
61 words
A tube drawing machine as claimed in claim 5, in which a basket is provided below the block for collecting tubing shed from the block, the basket being mounted so that it can be rotated about the axis of the block, and means is provided for rotating the basket at a speed related to the speed of rotation of the block.
Claim 13
Independent Claim
201 words
A method of drawing thin wall metal tubing having a generally circular cross section with a rotatable drawing block and at a predetermined tension without substantially deforming the circular cross section of the metal tubing, comprising the steps of providing a drawing block with an endless peripheral annular groove defined by two opposed annular wedging surfaces converging at a predetermined relatively acute angle toward the rotational axis of the drawing block for releasably gripping the tubing, without enlarging the cross sectional dimension of the tubing in the direction parallel to the axis of the drawing block, as the tubing is drawn under the predetermined tension into frictional engagement with the wedging surfaces and around a section of less than 360* of the annular groove as the drawing block rotates, rotating the drawing block to draw the tubing into the peripheral groove in frictional engagement with said wedging surfaces, and maintaining the tubing in frictional engagement with the wedging surfaces along said annular section of less than 360* and urging the tubing into said annular section with a radial force, substantially less than and established independently of the drawing tension, sufficient to prevent slip between the tubing and the opposed wedging surfaces.
Claim 14
Independent Claim
201 words
A method of drawing thin wall metal tubing having a generally circular cross section with a rotatable drawing block and at a predetermined tension without substantially deforming the circular cross section of the metal tubing, comprising the steps of providing a drawing block with an endless peripheral annular groove defined by two opposed annular wedging surfaces converging at a predetermined relatively acute angle toward the rotational axis of the drawing block for releasably gripping the tubing, without enlarging the cross sectional dimension of the tubing in the direction parallel to the axis of the drawing block, as the tubing is drawn under the predetermined tension into frictional engagement with the wedging surfaces and around a section of less than 360* of the annular groove as the drawing block rotates, rotating the drawing block to draw the tubing into the peripheral groove in frictional engagement with said wedging surfaces, and maintaining the tubing in frictional engagement with the wedging surfaces along said annular section of less than 360* and urging the tubing into said annular section with a radial force, substantially less than and established independently of the drawing tension, sufficient to prevent slip between the tubing and the opposed wedging surfaces.
References Cited (Backward Citations)
US1316411A
Cited
US3106354A
Cited
US3235202A
Cited
US3232553A
Cited
US3319451A
Cited
US3270979A
Cited
US3373818A
Cited
US3331566A
Cited
US3496751A
Cited
US3593558A
Cited
US3765215A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |