Machine tools abstract
A loading device for sequential loading of bars in machine tools
comprises chutes (16) for arrival of a bar against stops (17) for
stopping in a withdrawal position. Beyond the stops (17) there is
a guide (2020') for axial sliding of a bar in a direction aligned
with the inlet of a machine tool (14). Raising elements (22) have
their upper surface (23) inclined and terminating with a stop part
(24) arranged substantially vertically to the guide (2020'). Said
raising elements (22) are mobile between a first position below
the chutes (16) and the guides (2020') and a second position above
the stops (17) and the guides (2020') in which they raise the bar
placed in the withdrawal position to cause sliding onto the upper
inclined surface (23) toward the guide ( 2020') to a stop position
(26). Upon return of the raising elements to the first position
the bar in the stop position (26) is placed on the underlying guides
(2020') to be pushed by (pushers) (3738) into the machine tool.
Machine tools claims
I claim:
1. Loading device for loading of bars in a machine tool comprising
in combination:
downwardly inclined chutes for moving a bar downwardly in an inclined
plane and against chute stops located adjacent the lower ends of
said chutes, and into a withdrawal position on said chutes,
a plurality of guides for supporting a bar for axial sliding movement,
said guides being arranged adjacent said stops and disposed to support
a bar for axial insertion into the machine tool,
raising elements extending between the chutes and the guides and
having thereon upper surfaces inclined in part downwardly and terminating
with upwardly inclined stop parts, and the raising elements being
movable vertically between a first nonoperating position below the
chutes and the guides, and a second operating position in which
said upper surfaces thereof move above the chute stops and the guides
thereby raising the bar placed in the withdrawal position to a height
above the chute stops and causing said bar to slide on the downwardly
inclined surfaces of said elements toward the guides to a stop position
against the stop parts, and upon return of the raising elements
into their nonoperating position causing the bar in the stop position
to be laid on the underlying guides,
pushing and gripping means registering coaxially with the bar in
said guides and operable to move axially the bar laid thereon along
the guides to introduce the bar into the machine tool and subsequently
to extract therefrom at least a remnant of the bar from the machine
tool along the guides, and
means for effecting disengagement of the bar remnant from the pushing
and gripping means so that the remnant falls to an unloading position.
2. Loading device in accordance with claim 1 characterised in that
the pushing and gripping means comprise at least a first pusher
terminating at a free head end with an element for engagement of
one end opposite to the machine tool of the bar on the guides, the
loading device also comprising means of insertion and withdrawal
of said free head end in the engagement element for axial movement
of the bar respectively toward and away from the engagement element.
3. Loading device in accordance with claim 2 characterised in that
the insertion and withdrawal means comprise an insertion & extraction
device comprising a pair of jaws facing each other transversely
to the extension of the bar on the guides and closed by means of
an actuator to grip between them the bar, and the insertion &
extraction device being also supported for movement longitudinally
with respect to the bar to draw near or away from the engagement
element.
4. Loading device in accordance with claim 2 characterised in that
the pushing and gripping means comprise at least a second pusher,
said first and second pushers being supported for movement transversely
for their alternating alignment with the bar on the guides, and
the second pusher pushing the bar on the guides for a first section
toward the machine tool and the first pusher pushing the bar on
the guides for a second section toward the machine tool.
5. Loading device in accordance with claim 1 characterised in that
the guides comprise a plurality of elements in the shape of the
letter U aligned parallel to the extension of the bar on the guides.
6. Loading device in accordance with claim 5 characterised in that
the guide elements are movable transversely with said second pusher
to be replaceable by the first pusher upon its alternating alignment
with the bar on said guides.
7. Loading device in accordance with claim 1 characterized in that
each of the raised stop parts comprises part of an upper surface
of a raising element inclined opposite the downwardly inclined part
of the upper surface to define therewith substantially a seat for
receiving the bar, the upper surface being shaped like the letter
V for holding a bar at the stop position.
8. Loading device in accordance with claim 1 characterised in that
the raising elements comprise a plurality of raising blades parallel
to each other and arranged at intervals in a direction parallel
to the axis of the bars located on the raising elements.
9. Loading device in accordance with claim 1 characterised in that
the raising elements perform a linear operation with horizontal
movement connected to an end of an arm of a bell crank pivoted centrally
to a fixed support and with the other end connected in a jointed
manner to a support, the raising elements being constrained to move
vertically upon operation of the bell crank.
10. Loading device in accordance with claim 9 comprising two bell
cranks arranged at the ends of a beam, the beam having near its
ends carriages for running along vertical guides.
11. Loading device in accordance with claim 2 characterised in
that the engagement element of the first pusher rotates freely relative
to the rest of the first pusher.
12. Loading device in accordance with claim 1 characterised in
that the pushing and gripping means comprise chain moving means.
Machine tools description
BACKGROUND OF THE INVENTION
The present invention relates to a loading device for sequential
feeding of bars into a lathe, e.g. the numerical control type.
In the field of automatic lathes the problem of sequentially feeding
the bars to be machined is well known. Indeed, it is usually necessary
to respect relatively short loading and unloading times while at
the same time avoiding bar positioning errors and jamming of the
machine. This is particularly problematical when the bars to be
supplied are relatively heavy because of the inertia of the settling
movements that the bars make. For example, in known loaders the
bars are often made to run on a moving inclined plane at the end
of which is an axial sliding guide for the bar toward the machine
tool. The bar running on the inclined plane thus falls into the
guide. Especially in the case of relatively heavy bars the lateral
velocity of the bar in falling on the guide is such as to make likely
jumping over the guide and consequently jamming of the loader. It
is also likely that a relatively heavy bar in falling into the guide
would cause vibrations and shocks which could damage the structure.
SUMMARY OF THE INVENTION
The general purpose of the present invention is to supply a loader
for machine tools such as lathes which would feed with high speed
and accuracy even heavy bars while avoiding possible jamming situations.
In view of said purpose it was sought to provide in accordance
with the present invention a loading device for loading of bars
into a machine tool comprising in combination:
inclined plane chutes for arrival of a bar against stops in a withdrawal
position,
an axial sliding guide for a bar with said guide being arranged
beyond said stops and aligned with an axial insertion position for
a bar in the machine tool,
raising elements arranged substantially between the withdrawal
position and the guide and having the upper surface inclined downward
in the direction of said guide and terminating with a raised stop
part arranged substantially vertically to the guide and the raising
elements being mobile between a first nonoperating position below
the chutes and the guides and a second operating position above
the stops and the guides in which the raising elements raise the
bar placed in the withdrawal position up to a height greater than
the stops to cause sliding on the upper inclined surface toward
the guide to a stop position against the stop and upon return of
the raising elements into the nonoperating position the bar slides
into the stop position being placed on the underlying guides,
pushing and gripping means moving coaxially to the guide to move
axially the bar placed on them along the guide to introduce the
bar into the machine tool add subsequently withdraw at least a remnant
thereof from the machine tool along the guide, and
disengagement means for the bar remnant from the pushing meads
for its falling to an unloading position.
BRIEF DESCRIPTION OF THE DRAWINGS
To clarify the explanation of the innovative principles of the
present invention and its advantages compared with the known art
there is described below with the aid of the annexed drawings a
possible embodiment by way of nonlimiting example applying said
principles. In the drawings:
FIG. 1 shows a schematic plan view of a feeding and unloading device
in accordance with the present invention,
FIGS. 2 and 3 show perspective, schematic and partial views of
a first and second part respectively of the device of FIG. 1
FIG. 4 shows a schematic and partial view of a cross section of
the device of FIG. 1
FIG. 5 shows a side view of a third part of the device of FIG.
1
FIG. 6 shows a perspective, schematic and partial view of a fourth
part of the device of FIG. 1 and,
FIG. 7 shows an enlarged view of a detail of the device of FIG.
1.
DETAILED DESCRIPTION OF THE INVENTION
With reference to the figures FIG. 1 shows schematically a loading
device indicated generically by reference number 10 comprising a
first part 11 and a second part 12 of a guide for a bar 13 to be
fed by axial insertion into a machine tool, e.g. a spindle 14 belonging
to a lathe of the known art and therefore not further illustrated.
Laterally and parallel to the first and second parts 11 12 is placed
a chute 16 made up e.g. of several parallel cross pieces 16 for
supply of bars 15 (shown in broken lines in FIG. 1) to be taken
sequentially. As seen also in FIGS. 2 and 4 at the end of the inclined
plane are placed stops 17 against which butts the first bar of the
sequence 15 supplied on the chute.
As seen in FIG. 1 the first and second parts of the guide comprise
a guide made up of an aligned sequence of guide supports in the
shape of the letter U 20', 20 respectively.
Said supports can be e.g. supported by arms 21 appropriately anchored
in a slightly elastic manner for absorption of vibrations during
operation of the machine.
As seen better in FIG. 2 aligned below between the first bar to
be withdrawn butted against the stops 17 and the guide 20 20' are
arranged raising elements consisting of raising or withdrawal blades
22. As is clear also from FIG. 4 the blades 22 have the upper surface
formed generally like the letter V with a first part 23 inclined
downward away from the stops 17 and terminating with a second part
or stop rise 24 e.g. consisting of a surface oppositely inclined
upward after passing a stop point 26 vertically beneath the guides.
The two surfaces 23 24 identify a V-shaped seat for reception of
a bar as described below.
The blades 22 are supported by means of a vertical movement to
move simultaneously on command between first lower nonoperating
positions shown in solid lines in FIG. 4 and upper operating or
withdrawal positions shown in broken lines in the same Figure.
In this manner, when the blades move to the operating position
they raise the first bar arranged against the stops 17 until they
cause it to jump over the stops. The bar indicated by reference
number 13' in FIG. 4 slides on the plane 23 until it is received
at the stop point 26 (bar 13" in FIG. 4 ). The stop rise 24
inclined upward blocks the movement of the bar which is positioned
accurately thanks to the advantageous V shape given by the meeting
of the inclined planes 23 and 24. At this point the blades 22 are
again lowered into the nonoperating position and the transferred
bar is thus rested in the guides 20 20' (bar 13 in FIG. 4) Transfer
of the bar between the chute 16 to which the bars can be fed manually
or by an automatic magazine and the axial insertion guide in the
machine is in this manner fast and safe, the bar being accurately
stopped vertically to the guide before being deposited with a simple
vertical movement.
FIG. 3 shows schematically add partially a possible embodiment
of a vertical movement mechanism for the blades. As seen in said
Figure the blades 22 are all supported by a beam 25 longitudinal
to the machine 10 and moving vertically thanks to carriages or roller
27 placed at its two ends and sliding along vertical guides 29.
The beam 25 is connected through two crank mechanisms 31 to the
ends of a control rod 32 which translates horizontally by means
of a piston operated linear actuator 33. FIG. 3 shows a single end
of the beam and single crank mechanism.
The other end and the other crank mechanism are equivalent. As
seen in the figures the crank mechanism consists of a bell crank
34 pivoted centrally at 35 to a fixed support 36. One end of the
bell crank 34 is pivoted to the control rod 32 while the other end
is pivoted to a tierod 52 which is in turn pivoted to the beam 25
in this manner it is clear that when the actuator 33 moves the rod
32 horizontally the crank mechanisms push the beam 25 to slide with
its ends along the guides 29 causing said vertical movement of the
plurality of blades.
When a bar 13 is housed in the guides 20 20' aligned with the
loading input of the machine tool a pushing unit pushes axially
the bar to introduce it in the machine and then withdraw from the
machine the residual bar length of the machining.
To limit the length of the device the solution described below
has been found advantageous.
The guide supports 20 belonging to the guide part 12 closer to
the machine to be fed are stably aligned with the bar inlet in the
machine tool 14. The guide part 11 comprises a carriage 18 on which
is supported the first row 20' of supports in the shape of the letter
U and a second row 30 of supports parallel to the first. The carriage
18 is mobile transversely to the extension of the guides to bring
into alignment with the fixed guide 12 alternately the guide supports
20' or 30 of the part 11. The transverse movement of the carriage
18 can be e.g. obtained by its running along tracks 28 by means
of a compressed air piston 19.
As seen again in FIG. 1 aligned with the guides 20' and 30 are
placed two pushers 37 38 mobile axially to the respective guides
to slide in the channel formed thereby. The pusher 37 is mobile
with its free end between a retracted position or rear stop shown
in solid lines in the figures and a front stop position beyond the
guides 20' shown in broken lines and indicated generally by reference
number 37'. The pusher 38 is mobile with its free end between a
retracted or rear stop position in which as seen again in FIG. 1
it is received with its free end just beyond the guides 30 and a
front stop position in which its free end is near the machine 14.
For example, in FIG. 6 is shown a possible device for movement
for the pusher 37 and the one for the pusher 38 could be equivalent.
As seen in said Fig. the end of the pusher opposite the guides is
supported by a carriage 39 running along a track 40 parallel to
the guides by means of a powered chain 41.
As seen again in FIG. 1 the pusher 38 has on its pushing end a
known elastic pincer engagement element 42 for a tail end of the
bar to be fed. Facing the pincer 42 are placed means of insertion
add extraction comprising an inserter & extractor device 43
for the bar in said pincer. With reference to FIG. 5 the inserter
& extractor 43 comprises a pair of jaws 44 facing each other
transversely to the extension of the bar to be gripped and commanded
to close by means of an actuator 45 e.g. a compressed air or oil
piston, with gear and rack movements. The inserter & extractor
is also mobile longitudinally to the bar to draw near or away from
the engagement end 42 of the pusher 38. To obtain the longitudinal
movement of the inserter & extractor the carriage 18 comprises
a first upper plate 46 bearing the inserter & extractor and
the guides 20', 30. Said first-plate 46 slides with its own lower
rollers 47 along longitudinal tracks 48 by means of a piston 49.
The tracks 48 and piston 49 are supported in turn on a second plate
50 below the first and in turn running with its own rollers 51 along
the guides 28 by means of the piston 19 to allow the above mentioned
transverse alignment movement of the guides 20' or 30 with the guides
20.
During use, operation of the loading device along a feed cycle
is as follows.
As described above, when it is necessary to load a new bar in the
machine tool 14 the piston 33 is operated so that the blades 22
rise toward their upper operating position while withdrawing the
bar waiting against the stops 17. Upon reaching the top of the stops
17 the bar slides along the upper inclined surface of the blades
22 until it stops in position 26 and is then laid on the aligned
guides 20 20' by means of the lowering of the blades toward their
lower nonoperating position.
At this point the pusher 37 is operated toward the bar tail to
push the bar with its head toward and inside of the spindle 14 of
the machine tool. The bar thus begins to rotate, being entrained
by the rotation of the machine tool spindle. The guides 20 20'
are mounted as mentioned in a dampened manner and dampen the vibrations
caused by the high speed rotation of the bar. As known in the field,
the guides 20 can have upper counterguides which close like jaws
once the bar 13 has been fed between them. For clarity of the drawings
said counter guides are not shown but can be equivalent to the guides
and are readily imaginable by a person skilled in the art.
Once the first pusher 37 has reached with its pushing end the position
37' which is slightly greater than the position of the head of the
second pusher 38 the first pusher is backed off to its starting
position and the piston 19 is operated to align the guides 20 30
for sliding of the second pusher 38.
The inserter & extractor is then commanded to tighten its jaws
on the tail end of the bar 13 as shown in FIG. 7 and the piston
49 is commanded to cause the inserter & extractor 43 to complete
a rearward travel toward the head 42 of the pusher. In this manner
the bar on the guides is engaged with its tail end in the engagement
element 42. The element 42 is supported on the pusher in a freely
rotating manner around the axis (in accordance with the known art
easily imaginable by a person skilled in art) so that the bar is
free to rotate even if engaged therein. Once the jaws 44 have reopened,
the bar engaged and supported by the pusher 38 can thus be pushed
thereby further inside the machine tool for the desired machining.
After completion of the machining cycle the pusher 38 returns to
its rest position as shown in FIG. 1 withdrawing from the machine
tool the residual bar length still engaged with the element 42.
The extractor 43 is commanded to grip the length and the carriage
18 completes its forward travel from the position shown in broken
lines to the position shown in solid lines in FIG. 7 so as to withdraw
the length from the engagement element 42. The jaws 44 then open
and the length falls into a collection area (not shown). The loader
is thus ready for a new cycle, withdrawing the next bar from the
inclined plane 16 and feeding it to the machine tool.
At this point it is clear that the pre-set purposes of having a
reliable and fast loader have been achieved. Naturally the above
description of an embodiment applying the innovative principles
of the present invention is given merely by way of example and therefore
is not to be taken as a limitation of the patent right claimed here.
For example, the exact form and proportions of the various parts
and the length of the loader and the number of guide elements 20
20', 30 can vary depending on the peculiar requirements of use and
dimensions of the bar to be handled.
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