Linear slide and swivel arrangement for a die mold lathe

A lathe to simultaneously machine two or more die molds in chucks of a headstock at one end of a bed used to support a saddle which is moved along a bed by a feed screw parallel to the rotational axes of the chucks. A drive in the headstock also rotates a master mold about a horizontal axis at a laterally-disposal location from the die molds. A probe provides a signal corresponding to the internal surface contour in the master mold to move cutting bars which always extend in a generally-parallel relation with the rotational axes of the chucks during machining of the die molds. A first swivel is carried by a cross slide upon the saddle. The first swivel is adjustable about a vertical axis to provide a desired angle between the direction of attack by the cutting bars and the horizontal axes of rotation by the chucks. A linear displacement assembly is supported by the first swivel and includes a movable member which is reciprocated by a piston and cylinder assembly for displacing the cutter bars according to the output signal from the tracer probe. A second swivel is supported by the movable member of the linear displacement members to angularly position tool support bars so that the bars extend in a generally-parallel relation with the horizontal axes. The tracer probe carried by a follower bar is supported by a swivel frame which is supported by the second swivel so that the follower bar extends in a generally-parallel relation with the cutter bars.

BACKGROUND OF THE INVENTION 
The present invention relates to a mchine tool of the type employed to 
carry out machining operations on die molds to duplicate the internal, 
external or transverse surface contours in a master mold. More 
particularly, the present invention relates to such a machine tool wherein 
the reciprocating movement of the cutting tools is along a course of 
travel that is angularly adjustable with respect to the rotational axes of 
the die molds as well as the master mold. 
In my prior U.S. Pat. No. 3,264,910, there is disclosed a machine tool to 
carry out simultaneous machining operations under the internal surfaces of 
die molds while movement of the cutting tools is controlled in response to 
an output signal from a probe after being brought into contact with the 
contoured surface of the master mold. As in my prior patent, the present 
invention, while not limited thereto, is particularly useful for 
constructing a duplicator apparatus which may include the use of multiple 
chucks each supported for rotation by a spindle. However, conventional 
lathes as well as the multiple spindle head assembly disclosed in the 
aforesaid patent suffer from the acute disadvantage that movement of the 
probe as well as the cutting tools during the duplication process for 
certain designs becomes impossible when the probe as well as the cutting 
tools are reciprocated parallel to the rotational axes of the master mold 
and die molds. The same is true when the cutting tools and a probe are 
horizontally moved transverse to the rotational axes of the mold dies and 
master mold. Thus, for example, in a master mold for glassware, 
distinctive and frequently very intricate designs are to be duplicated. 
When the master mold defines a design by projections into the cavity 
thereof along a conically-reduced surface or when the designs project from 
two abruptly-changing mold surfaces, the mold projections overlap in the 
plane of the probe. In other words, a probe cannot detect mold projections 
from one mold surface because of interference with mold projections from 
the immediately adjacent mold surface. The probe is constrained to move 
either parallel to the rotational axis of the die mold or horizontally 
transverse to this rotational axis. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a machine tool for 
reproducing a design or a pattern of a die mold while rotated about a 
horizontal axis in one or more workpieces while rotated about similar 
horizontal axes wherein cutter bars are reciprocated in a direction of 
attack at a selected angle defined between the reciprocating motion of the 
cutter bars and the rotational axes of the workpieces. 
It is a further object of the present invention to provide a 
linearly-displaced slide member supported by a swivel upon a saddle of a 
lathe or the like while the movable member of the linearly-displaced slide 
supports a second swivel so that one or more tool support bars are 
adjustably positioned to extend along an axis generally parallel to the 
rotational axis of a workpiece to undergo machining while the tool support 
bars are reciprocated along a linear course of travel which is angularly 
disposed with respect to the rotational axes of the workpieces. 
In accordance with the present invention, there is provided in a machine 
tool having drive spindles with chucks rotatable about parallel horizontal 
axes while separately supporting a pair of die molds for machining by 
simultaneously movable tools carried by elongated bars that are 
controllably positioned in response to a tracer probe output signal 
corresponding to internal surface contours in a master mold while rotated 
about a horizontal axis at a laterally displaced location from the chucks, 
the machine tool including a saddle displaced by a driven feed member 
longitudinally of a bed along courses of travel toward and away from the 
chucks and generally parallel with their horizontal axes of rotation, the 
combination including linear displacement means carried by the saddle to 
simultaneously reciprocate the tools along parallel directions of attack 
to machine a design into the internal surfaces of the pair of die molds, 
first swivel means supporting the linear displacement means upon the 
saddle to adjustably select a desired angle between the directions of 
attack by the tools and the horizontal axes of rotation of the chucks, 
second swivel means supporting the tools while carried by the linear 
displacement means to angularly position the tool supporting bars so that 
the bars extend in a generally parallel relation with the horizontal axes 
of rotation of the chucks, a follower bar including a tracer probe at one 
end for movement along the internal surface contours in the master mold, 
and a swivel carrier frame supported by the second swivel means to 
angularly position the follower bar while carrying the tracer probe so 
that the follower bar extends in a generally parallel relation with the 
horizontal axes of rotation of the chucks while reciprocated by the linear 
displacement means. 
In the preferred form of the present invention, the linear displacement 
means includes upper and lower slide members having linear bearings 
interposed therebetween, and a fluid actuator coupled to the slide members 
to displace the upper slide member relative to the lower slide member. A 
lower cross slide includes a movable member secured to the first swivel 
means for horizontally positioning thereof upon the saddle. An upper 
swivel means preferably supports a cross slide including movable members 
each adapted to support a tool holder which, in turn, supports a cutting 
bar and tool attached thereto. Tool holders, if desired, may be displaced 
by further slide means in a direction parallel to the rotational axes of 
the chucks.

In FIG. 1, only the lower portion 10 of a die mold is shown which is of the 
type employed for molds for pressing glassware but can be blow-molding 
glass container molds, etc. The mold is divided into mold halves along a 
parting line 11 or can be solid or block molds. The mold surface includes 
decorative projections at various locations, which include elongated 
spiral projections 12 having generally planar face surfaces extending from 
a tapered side wall of the mold. An intermediate mold surface includes 
diamond-like style decorations 13 which terminate just short of the actual 
bottom 14 of the mold. A decorative surface 15 may also project from the 
bottom 14. To machine these various decorative surface areas, it has been 
found unsatisfactory and even impossible in many instances to reciprocate 
a cutting bar 16 having a tool 17 at its projected end along an axis which 
is coaxial with the rotational axis of the die mold. This, of course, 
depends on the design and configuration of the die mold. However, in the 
die mold illustrated in FIG. 1, interference occurs during coaxial 
reciprocation of the cutting tool at the line of demarcation between the 
spiral projections 12 and the diamond-like style decorations 13. In other 
words, the tool cannot penetrate the mold material without interference 
with other decorative projections of the mold surface. To effect machining 
of a die mold as typically shown in FIG. 1, the present invention provides 
that the cutter bar 16 remains in its parallel relation with the 
rotational axis of the die mold when mounted on a machine tool but the 
reciprocation of the cutter bar is angular to any desired extent with 
respect to this rotational axis. This reciprocation is typically 
illustrated by arrow 19 in FIG. 1. 
Reference is now directed to FIGS. 2 and 3, wherein there is illustrated a 
lathe generally indicated by reference numeral 20 having a conventional 
lathe bed 21 including a pair of spaced, parallel V-ways 22 (only one 
shown). A saddle 23 has V-guides 24 arranged to project into the V-ways 22 
to guide the saddle for traversing movement along the bed while moved by a 
driven feed screw 25 which is coupled to the saddle by a feed nut 26. The 
feed screw 25 is driven in the usual well-known manner through gear 
reducers, not shown, but typically in the form of change gears that are 
rotated by a motor 27 forming part of headstock 28 of the lathe. The 
headstock of the lathe may be constructed in any well-known manner such as 
illustrated in my prior Patent No. 3,264,910. Essentially, the headstock 
includes a gearwheel 29 coupled to a worm gear 30 to rotate a plurality of 
spindles 31 through bevel gears 32. A further set of bevel gears 33 drives 
a spindle 34 employed to rotate a master mold 35 while spindles 31 rotate 
molds 36. The molds 36, being the workpieces, have a hollowed interior or 
exterior surface upon which a pattern is duplicated corresponding to the 
pattern defined by the master mold on its internal surface. 
The upper surface of the saddle 23 supports a main cross slide 40 having a 
movable member 41 guided by a dovetail guide for horizontal movement 
transversely with respect to the rotational axes of the spindles 31. In 
the embodiment of the invention shown in FIGS. 2 and 3, the movable member 
41 defines, by its upper surface, one part of a lower swivel 42 which 
includes a rotatable member 43. An annular T-slot 44 arranged coaxially 
with the vertical swivel axis supports bolts 45 which extend through 
openings drilled in the movable plate 43 so that hold-down nuts can be 
torqued to a desired extent for locking the movable swivel plate at a 
desired angle with respect to the rotational axes of spindles 36 and 
traversing movement of the saddle. This angular arrangement of the lower 
swivel brings about an angular positioning of a linear slide 46. The 
linear slide need not be part of the swivel plate 43. The linear slide 
includes linear bearings 47 disposed at opposite sides of a central 
projection 48 extending along the length of the swivel plate 43. The 
bearings 47 support at their opposite sides a movable slide plate 49. 
Linear motion of the movable slide 46 is provided by a piston and cylinder 
assembly 50. As illustrated in FIG. 2, the piston and cylinder assembly 50 
is secured at its cylinder portion by a bracket 51 to the movable plate 
49. The rod end of the piston is secured by a clevis mounting (not shown) 
to the central projection 48 of swivel plate 43. This arrangement of parts 
is such that the admission of hydraulic fluid to either side of the piston 
reciprocates the cylinder portion and thereby the movable plate 49 for 
linear motion of the slide. To minimize the dimension of the parts as well 
as the number of parts, the present invention also provides that the 
movable slide 46 is part of an upper swivel 52 which includes a swivel 
plate 53 movable about a vertical axis which corresponds to the vertical 
swivel axis of the lower swivel 42. The swivel plate 53 has a plurality of 
holes at spaced-apart locations about a circle to receive the shank 
portion of bolts 54 that are supported in an annular T-slot 55 formed in 
the movable plate 49 of the linear slide 46. 
Upon the top surface of the swivel plate 53 there is secured a stationary 
part 56 of a cross slide having a plurality of movable saddle members 57 
that are moved along the slide by a feed screw 58 (FIG. 2). The feed screw 
58 is employed to adjust the separation between block tool holder 59 that 
is also supported by linear slides 60 arranged to advance and retract 
cutting bars 61 into and out of the molds 36. The cutting bars 61 support 
in the usual well-known manner cutting tools at their projected end for 
machining the internal surface of the molds. 
The movable swivel member 53 includes an upstanding frame 62 secured to one 
end thereof to support a horizontally-arranged bracket 63. The bracket 
includes a swivel pin 64 and an annular slot 65 through which a lock bolt 
66 extends while secured to the stationary portion 67 of a linear slide 
68. A movable member of slide 68 supports a carrier 69 for a follower bar 
70 having a tracer pin extending laterally therefrom at its extended end 
to engage the internal surface of the master mold. 
As the master mold is rotated, the tracer pin is subjected to varying 
horizontally-directed pressures by the contour of the design. These 
pressures are translated into electrical signals by the transducer. The 
electrical signals are transmitted by line 71 to a control circuit 72 
which includes a valve. The control circuit 72 controls the speed and 
direction of movement of the cylinder portion of piston and cylinder 
assembly 50. Since the cutter bars 61 and follower bar 70 are ultimately 
supported by linear slide plate 49 of the linear slide, they move together 
in response to operation of the piston and cylinder assembly 50. More 
specifically, the follower bar is supported by the upper swivel and 
maintained parallel with the cutter bars 61 by appropriate adjustment 
about swivel pin 64. 
To carry out a machining operation according to the apparatus of the 
present invention, the lower swivel is positioned at a desired angle so 
that the movable plate thereof is angularly arranged with respect to the 
main cross slide 40. The lower swivel is then locked into this position by 
torquing the nuts associated with bolts 45 in the T-slot. This adjustment 
would normally bring about an angular position between the cutting bars 
and the rotational axes of spindles 31. However, the cutting bars remain 
parallel with respect to the axes of rotation of the spindles 31 through 
the use of the upper swivel by adjusting plate 53 to return the cutter 
bars to a parallel relation with the spindles. The linear slide 46 
displaces ultimately the cutting bars as well as the probe along the same 
direction of travel which is usually not coaxial with the rotational axes 
of the spindles. The swivel pin 66 is employed to angularly position the 
follower bar to maintain a parallel-extending relation with the cutting 
bars 61. The linear slide 68 is employed to position the follower bar 70 
in an axial direction. The position of the tools with respect to the molds 
36 is achieved through the combination of adjustments to the main cross 
slide 40, the upper cross slide 57 through the adjustment of feed screw 58 
as well as longitudinal positioning by slides 60. 
Although the invention has been shown in connection with a certain specific 
embodiment, it will be readily apparent to those skilled in the art that 
various changes in form and arrangement of parts may be made to suit 
requirements without departing from the spirit and scope of the invention.