Improvements in Apparatus for the Manufacture of Drawn Tubes.
Year: 1898

page_text: Date of Application, 28th May, 1898
Complete Specification Left, 23rd Feb., 1899-Accepted, 25th Mar., 1899
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for the Manufacture of Drawn Tubes.
:
We, HEINRICH EHRHARDT, Engineer, of 20,. Reichsstrasse, Dusseldorf," in the
Empire of Germany, and THE UNIVERSAL WELDLESS STEEL TUBES COMPANY
(EHRHARDT'S PROCESS) LD., of 11, Copthall Court, E.C., do hereby declare the
nature of this invention to be as follows:-
This invention relates to improvements in apparatus for the manufacture of
drawn tubes and is designed to effect the drawing of seamless or solid-drawn
tubes in a more rapid and convenient manner than has heretofore been possible.
An important feature of the said invention consists in causing the mandrel
and the dies whereby the drawing is effected, to move simultaneously towards
and away from each other, so that the movement of the draw rings relatively to
the tube which is being manufactured, is twice as rapid as it would be if either
the dies or the mandrel were stationary, such relatively rapid motion being
obtained however without the speed of the moving parts being unduly high.
A further important feature of the invention relates to an arrangement of
the dies in such a manner that they can be raised out of the way of the mandrel
to facilitate the placing of the work on the latter.
The invention also has reference to automatic reversing devices, and to means
for facilitating the removal of the work from the mandrel.
According to one construction of draw bench embodying the present improve-
ment, two head stocks carrying the mandrel and the dies respectively, are mounted
on guides which form the bed of the draw-bench. Each headstock is connected
to a rack by which it is worked to and fro. The racks are operated by two
pinions, one of which is situated near each headstock. The pinions are driven
by bevel gear from a side shaft extending along the draw bench, and having,
preferably about midway between its extremities, a suitable arrangement for
driving it in either direction. Such an arrangement may comprise for example
a pair of bevel wheels mounted loosely on the side shaft and driven in opposite
directions by a third bevel wheel situated between and at right angles to them.
The motion of the shaft is controlled by throwing one or other of the loose bevel
wheels into engagement with the shaft by means of clutches.
The automatic reversing arrangement comprises a series of lever arms and
links connected with the clutches, and a pair of stops connected with one of the
headstocks. The stops are so arranged that one of them will strike one of the lever
arms when the headstock has completed its rearward "movement, and the
other will strike the said arm at the end of the forward movement, with the
result in each case that the reversing gear is caused to change the direction of
motion. The tube may be acted upon by two or more dies at the same time
arranged one in advance of the other, thus reducing its thickness two degrees
for each working stroke.
A suitable buffer may be provided to arrest the movement of one or both of
the headstocks in their rearward movement.

page_text: Figure 4 is a cross section on line y-y Figure 2.
A and B are head stocks mounted so as to be capable of sliding between
grooves or guides in the bed C of a draw bench. a and b are toothed racks
respectively formed on or attached to the head stocks A and B. D and E are
pinions gearing with the toothed racks a and b respectively and carried by spindles
journalled in suitable bearings in the bed C. d and e are bevel gear wheels
respectively mounted on the spindles carrying the pinions D and E. F is a
rotary shaft journalled in brackets G, G, G, carried by the bed C.
9, g¹ are
bevel pinions gearing respectively with the bevel wheels d and e. g² and g³ are bevel
gear wheels mounted loosely on the shaft F. H is a bevel wheel, gearing with
the bevel wheels g² and g³ so as to drive the latter in opposite directions. h is
a pulley mounted on the spindle carrying the bevel wheel H and driven by a
belt from a suitable driving shaft. and are sliding clutches of ordinary
construction mounted on the shaft F so as to rotate therewith and adapted to
throw the bevel wheels into or out of gear according to the direction in
which it is required to drive the shaft F. J is a lever fixed to the top of a
vertical rod journalled in a sleeve carried by the bed plate C. is a link
fixed to the lower end of the rod ; and extending beneath the bed C parallel to
the lever J. is a connecting rod having its end at one extremity pivoted to
the link , and having its opposite end pivoted to links the opposite ends
of which are respectively fixed to pivots journalled in sleeves carried by
the bed C. are forked pieces respectively fixed to the pivots j, j and
provided with pins which take into annular grooves in the rotary sliding
clutches i, . K is a hand lever fixed to the pivot, for operating the clutches ii!
by hand when required.
I is the mandrel carried by the head stock A and is a tube thereon in
course of construction. a¹ and a² are studs or bosses on the head stock A, for
operating the clutches i, i N, N₁ are the dies, N2 is a funnel shaped guide,
and N is a pair of rolls, all carried by blocks arranged to slide in vertical
grooves in the head stock B. M is an inclined grooved rest fixed to the head
stock B and provided with a number of slots m corresponding to the blocks ».
m¹ is a rod or bar supported in suitable bearings from the rest M and carrying
a lever m² provided with a counter weight 0, and a number of levers m³ each of
which passes through a slot m and is connected by a link m to a block n.
When the lever m² carrying the counter weight () is depressed, the blocks n,
n, n, n, respectively carrying the guide N2 the dies N and N and the rollers N³,
are raised into the grooves of the inclined rest M and out of the path of the
mandrel L, thus allowing ample space for the blank from which the tubes are
drawn to be placed upon the mandrel.
P is a spring buffer attached to the bed C, against which the mandrel socket
strikes to arrest the movement of the head stocks in their rearward movement.
The movement of the shaft F is transmitted through the pinions g, g', the
bevel wheels d, e, and the pinions D and E, to the head stocks A and B.
As shown in the drawings, the clutch is in engagement with the bevel
wheel g² and the head stocks are approaching one another during the formation
of a tube. At the completion of this stroke the stud a' strikes the lever J
moving it to the right and thereby, (through the link connecting rod ³,
links and forks j, j), throws the clutch out of engagement with the
bevel wheel and the clutch into engagement with the bevel wheel g³, thus
reversing the direction of rotation of the shaft F and causing the head stocks to
recede from one another. At the end of this receding stroke the mandrel socket
strikes the buffer P which prevents any sudden jar, and the stud or boss a
strikes the lever and moves it to the left thus throwing the clutch out of
engagement with the bevel wheel g³ and the clutch again into engagement
with the bevel wheel ², the movement of the shaft F being thus reversed and
the head stocks again approaching one another.
When it is required to bring the head stocks to rest the clutches and ¿¹