Machine tools abstract
The invention relates to a feed device for machine tools with chuck
arranged at the free end of a spindle, to which chuck the workpiece
is fed axially through the inside of the spindle from the rear by
means of compressed air from a compressed air nozzle through the
spindle (1) into the chuck (2), having a tool station arranged in
front of the head of the chuck and having a stop which comes in
front of the head of the chuck (2) in synchronism with the machining
for halting the movement of the individual workpiece (8). In order
to increase the productivity, a brake member is arranged in the
axial hollow (11) of the spindle (1) between the entrance end and
the chuck (2).
Machine tools claims
I claim:
1. A machine tool with feed device comprising
a chuck arranged at a free end of a continuously turning spindle
to which chuck an individual workpiece is fed axially through an
axial hollow inside of the spindle from a rear by means of compressed
air from a compressed air nozzle through the continuously turning
spindle into the chuck,
a tool station arranged in front of a head of the chuck,
a stop which, in a machining cycle, comes in front of the head
of the chuck in order to stop movement of the individual workpiece,
a brake member arranged in the axial hollow of the spindle between
an entrance end thereof and the chuck, said brake member having
a form of a transition step of a first spindle section and a second
region, said transition step allowing passage of the workpiece completely
therethrough, the compressed air pressing the workpiece against
said step for stopping the workpiece,
for feeding of the workpiece having a non-circular cross section,
the second region has a non-circular cross section which is adapted
to the non-circular cross section of the workpiece, and the first
spindle section has a cross section which surrounds the workpiece,
and
said transition step is so arranged behind the head of said chuck
that the workpiece leaves the brake member with reduced speed in
order to come against said stop.
2. A feed device according to claim 1 wherein the brake member
is arranged directly in front of the chuck.
3. A feed device according to claim 1 further comprising a chute
which receives the individual workpieces lying one behind the other,
and a separating device arranged between the chute and the entrance
end of the axial hollow of the spindle for separating workpieces
in an introduction position in front of the entrance end of the
spindle hollow, wherein the compressed nozzle is arranged to the
rear of said separating device.
4. A feed device according to claim 3 wherein the separating device
comprises a slide which is moved back and forth in synchronism.
5. A feed device according to claim 4 wherein the separating slide
has a groove which comes below the chute for dropping therein of
the individual workpiece, which groove is closed by a cover of the
device after the slide has moved into its position in front of the
entrance end of the spindle.
6. A feed device according to claim 1 wherein the stop for the
halting of the individual workpiece is formed by a finger which
moves back and forth in synchronism with the machining.
7. A feed device according to claim 1 wherein the transition step
from the surrounding cross section to the non-circular cross section
lies in a region of the chuck.
8. A feed device according to claim 1 wherein said tool station
developed as a fly-cutter milling head, a tool shaft of which extends
in front of the head of the chuck, is offset with respect to the
spindle, and rotates in a constant speed ratio to the spindle, wherein
the speed ratio is dependent on a number of profile surfaces to
be produced on a free end of the individual workpiece.
9. A feed device according to claim 8 wherein said stop has the
configuration of a finger, and the tool shaft is arranged opposite
the finger of the stop.
10. A feed device according to claim 1 further comprising
an angular-position adjustment member (K) which is arranged resting
on the non-circular region (4) and spring-biased in radially inward
direction, is associated with the transition step (28).
11. A feed device according to claim 10 wherein the angle-position
adjustment member is formed as a rolling body with curvature of
outer surface in axial direction and facing the direction of transport
of the workpiece.
12. A feed device according to claim 11 wherein with a hexagonal
cross section of the non-circular region, three rolling bodies spaced
at equal angles apart are provided.
13. A feed device according to claim 12 wherein the rolling bodies
are balls which protrude to corner-to-corner distance of a polygon.
14. A feed device according to claim 10 wherein the brake member
further comprises a resiliently retractable projection extending
into the cross section of a rotating feed channel formed by the
axial hollow of the spindle.
Machine tools description
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a feed device for machine tools
which has a work chuck arranged on the free end of a spindle in
accordance with the preamble to claim 1.
Such a device is known from U.S. Pat. No. 4794831. In that case,
workpieces which are individualized to the rear of the spindle are
blown by means of a nozzle rearward into the inside of the spindle.
A second nozzle which is displaceable in the axial direction of
the spindle is present in front of the head of the chuck. The head
of this nozzle is developed as a rubber stop. Upon the insertion
of the workpiece from the rear, this rubber stop is displaced in
front of the chuck so that the individual workpiece introduced is
stopped by striking against this stop. After the machining of the
workpiece, the spindle opens and the second compressed-air nozzle
blows the workpiece through the spindle back out of the chuck.
SUMMARY OF THE INVENTION
The object of the invention is further to develop a feed device
of the type in question in a manner simple to manufacture so as
to increase its productivity.
As a result of the development of the invention, the productivity
of the apparatus has been increased. Between the entrance end and
the chuck, a brake member is arranged. An individual workpiece which
is introduced into the entrance end of the axial hollow of the spindle
is braked by means of the brake member before reaching the stop.
In this way, the workpiece enters the chuck with reduced speed.
The momentum of the workpiece upon striking the stop is thereby
reduced. In this way, damage to a, for instance, pointed workpiece
upon striking against the stop is advantageously prevented, despite
the high speed of introduction. In addition to this, the tendency
for the workpiece to rebound from the stop and to come to rest only
after repeated striking against the stop until it is grasped by
the chuck is reduced. In accordance with the invention, the workpiece
is introduced by the action of compressed air into the entrance
end of the axial hollow of the spindle. By the continuous action
of compressed air, the workpiece is accelerated in the axial hollow.
Before reaching the chuck, the speed is reduced by the brake member,
so that the workpiece leaves the brake member with reduced speed.
The brake member is preferably formed by a change in cross section
of the axial hollow. In this connection, the axial hollow can first
of all have a round projection between the entrance end and the
brake member and, behind the brake member, a cross section other
than circular so that the brake member is formed by the change in
cross section. The braking of the axial movement of the workpiece
takes place at the same time as a rotary acceleration of the workpiece
to the speed of rotation of the spindle. The brake member is preferably
arranged directly in front of the chuck. It is advantageous if the
brake member is developed as a resiliently yieldable projection
which enters into the cross section of the axial hollow. A workpiece
which is introduced through the feed channel formed by the axial
hollow is braked by displacement of the brake member. However, it
is also provided that the brake member is formed by a friction surface
which can also extend resiliently into the cross section of the
axial hollow. The axial hollow preferably rotates in the region
of the brake member. In this way, the speed of rotation of workpiece
and spindle is synchronized. It is advantageous if only a single
nozzle is used for the loading and unloading. The compressed air
is fed from of the compressed-air nozzle arranged to the rear of
the chuck twice per machining cycle in the same direction. With
the first air pulse, the workpiece is introduced into the chuck.
After striking against the stop, movement is removed from the workpiece.
As a result of the fact that the compressed air is still flowing,
a rebounding of the workpiece which may then take place is harmless.
The workpiece is moved again and again towards the stop by the compressed
air so that it comes to rest there within a very short time. After
the stop is moved back and the machining of the workpiece has taken
place, the chuck and the second pulse of compressed air pushes the
workpiece out of the chuck, past the stop which has been moved back.
The workpiece then lands in a workpiece receiving device which is
arranged, for instance, below the spindle. The further development
is characterized by increased economy. As compared with the aforementioned,
and particularly other, known developments, the machining times
per piece can be considerably reduced. The workpieces are not, as
is customary, pushed one after the other through the spindle from
the rear, but they are, in each case, driven as individual workpieces
by compressed air through the spindle with the chuck open. The stop
which passes, in the machining cycle, in front of the head of the
chuck prevents the individual workpiece from dropping out of the
chuck. By means of the stop the result is obtained that a quiet
required protrusion of the workpiece beyond the chuck is always
present. With this, precise machinings of the workpieces are possible.
As soon as the workpiece has reached its proper position limited
by the stop, the chuck closes, the stop moves back, and the machining
of the workpiece at the tool station commences. The introduction
of the individual workpiece by compressed air can take place with
the spindle in operation so that the starting and stopping times
do not constitute loss times upon the machining. As workpiece to
be machined a screwdriver-bit blank preferably enters into consideration.
It has a hexagonal clamping section seen in cross section and a
cylindrical front section in which a profiling is then cut by milling
tools. The stop against which the workpiece is pushed is preferably
displaced transverse to the direction of the spindle axis. In this
connection, either a linear displacement perpendicular to the direction
of the spindle axis or a swinging displacement can be provided.
In the case of the latter, the axis of swing of the stop is preferably
parallel to the spindle axis. As a result of this development, the
distance of the stop from the chuck can be reproducibly repeated.
One advantageous further development consists therein that the
compressed air is fed in two pulses per machining cycle of the workpiece
in the manner that the one pulse serves for feeding the workpiece
and the next pulse for ejecting it past the backward moved stop.
It has been stated above that the stop is moved back during the
machining of the workpiece. It initially remains in this position.
After the completion of the machining, the chuck opens so that the
brake member can be driven out of the chuck by compressed air. The
stop then moves into its stop position. Thereupon, upon the next
pulse, the workpiece is passed through the spindle to the chuck
until it strikes against the forwardly moved stop.
Furthermore, the solution in accordance with the invention is characterized
by the fact that, for the feeding of workpieces of non-circular,
for instance polygonal, cross section, for instance bits, the compressed
air forces the workpiece against a continuously rotating transition
step between a non-circular cross-sectional shape adapted to the
cross section of the workpiece and a cross-sectional shape, surrounding
this, of the axial hollow of the spindle and transfers it to the
non-circular region for rotational entrainment after the braking
of the axial movement. In this connection, the axial hollow which
is developed in the form of a bore, forms the surrounding cross-sectional
shape which the non-circular region adjoins. The latter is adapted
to the cross section of the polygonal bit. The bit, which is acted
on by the compressed air, passes through the axial hollow and is
halted by the step since, as a rule, there is no aligned agreement
between the cross sections of non-circular region and bit and simultaneous
synchronization of the speed of rotation. Due to the inherent inertial
of the bit, a relative displacement takes place between bit and
non-circular region so that the bit also enters into a position
aligned with the non-circular region. The compressed air can therefore
force the bit further up against the stop. The form-locked holding
of the bit which is then present leads to a good rotational driving.
Furthermore, the chuck need only be opened slightly in order to
be able to receive the bit. Savings in time upon the closing and
opening of the chuck result also from this.
In order for the workpieces to be passed individually through the
axial hollow, a chute which receives the individual workpieces lying
one behind the other and a device arranged between the chute and
the entrance end of the axial hollow of the spindle are provided,
for the separating in each case of one workpiece into the introduction
position in front of the entrance end to the rear of which separation
device a compressed air nozzle is arranged. The chute can in this
connection be developed in the form of a pipe which is passed through
by the workpieces. From there, the individual workpieces pass into
the introduction position in front of the entrance end.
In detail, the separation device is characterized by the fact that
it consists of a slide which is moved back and forth in synchronism.
The individual workpieces come on to it after leaving the chute
and are then brought into the insertion position by displacement
of the slide.
It is furthermore provided in accordance with the invention that
the stop for the halting of the individual workpiece is formed by
a finger which moves back and forth in synchronism with the machining.
Thus, it cannot happen that the shooting out of the workpiece by
compressed air is prevented. The finger assumes its advance position
only when an individual workpiece is introduced.
In accordance with the invention, it is provided that the transition
step from the surrounding cross section to the non-circular cross
section lies in the region of the chuck.
Different machinings can be produced on the workpiece in the manner
that the tool station is developed as fly-cutter milling head the
tool shaft of which extends, offset with respect to the spindle,
in front of the head of the chuck and rotates in a constant speed
relationship to the spindle which is dependent on the number of
profile surfaces to be produced on the free end of the individual
workpiece. If a tool shaft which extends transverse to the spindle
is present, then longitudinal grooves can be produced on the workpiece.
An alignment of the tool shaft parallel to the spindle makes it
possible to produce polygonal surfaces on the workpiece.
In order that the stop and tool shaft do not detrimentally affect
each other, the tool shaft is arranged opposite the finger which
forms the stop.
Furthermore, it is also advantageous, in accordance with the invention,
for the separating slide to have a groove coming below the chute
for the dropping-down of the individual workpieces, which groove,
after passage of the slide into its position in front of the entrance
end of the spindle, is closed by a cover of the device. In this
way, the passage of the individual workpiece from the chute to the
slide can take place without problem. If the slide then moves into
the transfer position, the groove is closed on the top so that the
compressed air shoots the individual workpiece as intended in the
direction of the chuck.
The alignment with correct angle of rotation in combination with
the braking of a polygonal bit with the non-circular region is improved
by angle-position adjustment members which are associated with the
rotating transition step, come against the polygonal surfaces of
the workpiece, are arranged in accordance with the non-circular
region, and are acted on with spring action in radial inward direction.
These adjustment members effect a positive rotational alignment
of the polygonal workpiece in the manner that the aligned arrangement
of workpiece cross section and that of the non-circular region is
present. The alignment with respect to the non-circular region takes
place even with maximum turned position of the workpiece, and to
be sure for a very short time. On the other hand, the angle-position
adjustment members are so positioned that, in the event of a possible
aligned arrangement of the polygonal workpiece to the non-circular
region, they do not prevent the transport of the workpiece.
It has proven advantageous to develop the angle-position adjustment
members as rolling bodies with curvature of the outer surface facing
the direction of transport of the workpiece lying in axial direction.
The curvature of the outer surface of the rolling bodies produces
in this connection, in a certain respect, a centering effect with
the avoidance of even only a brief back-up in connection with the
passage of the workpiece.
If the workpiece is developed as a hexagonal screwdriver bit, it
is advisable, with the non-circular region also having a hexagonal
cross section, to provide three rolling bodies arranged at equal
angles apart.
As an alternative, it is possible for the rolling bodies to be
developed as balls which protrude beyond the size of the polygon.
This shape is very simple from a structural standpoint and it is
characterized by a high degree of reliability. It is constantly
seen to it that the balls do not extend too far into the passage
region for the workpiece.
Differing from the device of this type in accordance with U.S.
Pat. No. 4794831 the feeding of the compressed air is effected
by a single compressed air nozzle which forces the compressed air
through the spindle always in the same direction.
The development of the brake member as spring-mounted rolling bodies
developed as balls is, however, used also independently of the cross-sectional
shape of the workpieces. It is important for the brake members to
extend in cross-section-reducing manner into the feed channel. The
workpiece of rotational symmetry is then braked when the largest
cross section of the workpiece is greater than the cross-sectional
contour of the feed channel reduced by the brake members.
BRIEF DESCRIPTION OF THE DRAWINGS
With the above and other advantages in view, the present invention
will become more clearly understood in connection with the detailed
description of preferred embodiments, when considered with the accompanied
drawings, of which:
FIG. 1 is a longitudinal section through the apparatus, plus spindle,
with the chuck of which there is associated a tool shaft, in the
case of the first embodiment;
FIG. 2 is a view in the direction of the arrow II of FIG. 1;
FIG. 3 is a view in the direction of the arrow III of FIG. 2 partially
broken away;
FIG. 4 is a top view of the device with slide in loading position;
FIG. 5 is a view corresponding to FIG. 4 the slide being in the
insertion position;
FIG. 6 shows diagrammatically the loading position of the slide
with the stop moved back;
FIG. 7 is the following showing in which the slide has moved forward
into the position of introduction of the workpiece, with the stop
having passed into the resting position;
FIG. 8 is the subsequent showing with the stop moved back and the
tool shaft having passed into operating position and the slide assuming
the loading position;
FIG. 9 is a following showing in which the completely machined
workpiece is ejected by means of the compressed air nozzle;
FIG. 10 is, in an individual showing, a longitudinal section through
the end of the spindle facing the chuck, the angle-position adjustment
members being provided in the region of the transition step, in
the case of the second embodiment of the apparatus;
FIG. 11 is a section along the line XI--XI in FIG. 10;
FIG. 12 is a detail showing of a cross section through the spindle
in the region of the angle-position adjustment members, the hexagon
of the workpiece assuming its most unfavorable alignment of rotation
with respect to the angle-position adjustment members; and
FIG. 13 is a showing corresponding to FIG. 12 in which the angle-position
adjustment members developed as balls have protruded to the size
of the polygon, with the non-circular region of the chuck shown
in dashed line.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with the first embodiment, the rotationally driven
spindle of a fly-cutter milling machine is designated 1. On its
free end, the spindle bears an automatically closing and opening
chuck 2. The inner surfaces of the chuck jaws 3 form a non-circular
region 4 in the manner of a hexagonal hole. Transverse to the spindle
1 a tool shaft 5 of a tool station 6 extends in front of the head
of the chuck 2. The tool shaft 5 is equipped with a fly-cutter 7
and rotates in a constant speed ratio to the spindle 1. The speed
ratio is dependent on the number of longitudinal grooves 9 to be
produced on the free end of an individual workpiece 8. The individual
workpiece 8 in this embodiment is a screwdriver bit B. Its one end
is developed as a hexagon 10 while its other end has the longitudinal
grooves 9 in order to assure a form-locked engagement with a screw.
In FIG. 1 it is shown that the hexagon 10 lies in the non-circular
region 4 of the chuck 2 and is clamped there.
The chuck 2 is furthermore firmly attached to the spindle 1. This
means that the two rotate together. Centrally within the spindle
1 there is a continuous axial hollow 11. It has a circular cross-sectional
shape. The diameter of the axial hollow corresponds to the width
across corners of the hexagon 10 so that a screwdriver bit B can
pass through the axial hollow 11 the latter forming a cross-sectional
shape surrounding the hexagon 10.
In front of the entrance end 12 of the spindle 1 which is opposite
the chuck, there is a feed device 13 for the feeding of workpieces
8. In detail, the feed device comprises a chute 14 which receives
the individual workpieces lying one behind the other, the chute
being in the form of a pipe. The pipe rises obliquely. The lower
end of the chute 14 passes through a side plate 15 which is directed
perpendicular to the spindle 1. Via a base plate 16 it is connected
with a side plate 17 which is arranged parallel to it and is fastened,
stationary, to a housing indicated in dash-dot line which surrounds
the spindle 1. Between the side plates 15 17 there is guided a
slide 19 which forms a separating device which can be moved back
and forth in synchronism. The drive of the slide 19 is not shown
in detail, but is effected by compressed air in the embodiment shown.
With the separating slide 19 moved backward, an upwardly open groove
20 forward in the separating slide 19 for the reception of one individual
workpiece 8 each extends below the outlet opening of the chute 14.
A continuous blast opening 21 extends in the slide 19 parallel to
the groove 20. The center-to-center distance between groove and
blast opening 21 corresponds to the stroke of the slide 19. With
the slide 19 moved back, the blast opening 21 is aligned with the
axial hollow 11 and extends directly in front of the entrance end
12. Furthermore, in this position, the blast opening 21 is aligned
with a compressed air nozzle 22 which is held fast on the side plate
15 and is in communication with the blast opening 21. The compressed
air nozzle 22 is in communication with a compressed air generator,
not shown.
Furthermore, the machine tool has a guide, arranged in front of
the head of the chuck 2 to receive a stop 24 which is shaped as
a finger which moves backwards and forwards in phase with the machining.
The stop 24 moves up to the height of the axial hollow and constitutes
a limitation for the individual workpiece 8 received by the chuck.
The manner of operation is as follows:
The spindle 1 rotates continuously during the machining of individual
workpieces 8. This is true also during the opening and closing of
the chuck 2. FIGS. 4 and 6 show the starting position. In it, the
slide 19 is moved back; the same is true also of the stop 24. In
the backward-moved position of the slide 19 the groove 20 is aligned
with the outlet opening of the chute 14 so than an individual workpiece
8 can enter into the groove 20. Thereupon, the impulse for the displacement
of the slide 19 and of the stop 24 is given. The stop moves into
the position shown in FIG. 7 and its front region thus crosses the
middle line passing through the axial hollow 11. The slide 19 also
moves forward. In this way, the groove 20 comes into aligned position
with the axial hollow 11 of the spindle 1 and the compressed air
nozzle 22. In this forward position of the slide 19 the groove
20 is closed by a cover 25 which extends between the side plates
15 17. The compressed air nozzle 22 which expels compressed air
pulsewise is now fed with compressed air, as a result of which the
individual workpiece 8 is moved into the axial hollow 11 with the
spindle 1 rotating. The circular cross section of the individual
workpiece 8 enters into the non-circular region 4. It can then still
be the case that with hexagon 10 and non-circular region 4 not aligned,
the hexagon 10 rests on the transition step 26 between the surrounding
cross-sectional shape and the adapted cross-sectional shape. Due
to its inertia, however, the individual workpiece 8 passes with
its hexagon into aligned agreement with the non-circular region
4 of the chuck 2 whereupon the compressed air drives the individual
workpiece 8 further forward. The forward movement is limited by
the stop 24; see FIG. 7. A pulse transmitter 27 present on the stop
24 registers the proper position of the individual workpiece, whereupon
the chuck 2 closes and clamps the hexagon 10 in part or over its
entire length. At the same time, the stop 24 moves back while the
tool shaft 5 of the fly-cutter milling head which lies opposite
it moves into the machining position and machines the longitudinal
grooves 9 into the circular end section of the individual workpiece.
In synchronism with this, the slide 19 is also moved back so that
its groove 20 is aligned with the outlet opening of the chute 14.
A new individual workpiece 8 then enters into the groove 20. In
this backward displaced position, the blast opening 21 of the slide
18 is also aligned both with the axial hollow 11 of the spindle
1 and with the compressed air nozzle 22. As soon as the individual
workpiece 8 has been machined, the tool shaft 5 moves back into
its starting position. The chuck 2 opens and by the next cycle of
the compressed air nozzle 22 compressed air is conducted through
the blast opening 22 into the axial hollow 11 as a result of which
the machined individual workpiece 8 is ejected; see FIG. 9. The
process described above is then repeated.
As an alternative, it would also be possible to form the axial
hollow 11 with a non-circular cross section so that its cross section
is adapted to that of the hexagon 10. In such case, the transition
step would then be present at the entrance end of the spindle. In
the embodiment shown, the transition step 26 is located in the region
of the chuck 2.
Furthermore, it would be possible to associate two compressed air
nozzles with the separating device. The one nozzle can then serve
to expel the completely machined individual workpiece, while the
other nozzle effects the insertion of the individual workpiece.
In the embodiment shown in FIGS. 10 to 13 the same parts have
been provided with the same reference numerals. The spindle 1 which
bears the chuck 2 is also provided with an axial hollow 11 of circular
cross section. The spindle 1 together with the chuck 2 rotates
continuously, namely also during the loading of the chuck with a
screwdriver bit B as well as upon the removal thereof from the chuck
2. Furthermore, the inner surfaces of the jaws 3 of the chuck 2
form a central non-circular region 4 in the form of a hexagonal
hollow which is adapted in shape to the hexagon 10 of the individual
workpiece 8.
The direction of transport of the individual workpiece 8 is indicated
by x in FIG. 10. In the immediate vicinity in front of the transition
step 28 between axial hollow and non-circular region 4 a bushing
29 which is connected, fixed for rotation, with the spindle 1 in
a manner not shown in detail, receives three angle-position adjustment
members K which are arranged a uniform angle apart. In the embodiment
shown, they are developed as rolling bodies, namely as balls 30
which are urged by spring in radial inward direction. A central
bore 31 of the said bushing 29 forms the extension of the axial
hollow 11. The diameter of the axial hollow 11 and that of the bore
31 are the same. Holes 32 are formed in the bushing 29 to receive
the balls 30 in such a manner that the diameter of the balls decreases
towards the bore 31. The balls 30 can therefore be displaced only
a given amount in radial inward direction, namely by the compression
springs arranged in the holes 32. The center lines M placed through
the holes 32 are perpendicular to the hexagon surfaces of the non-circular
region 4.
If the individual workpiece 8 is blown through the axial hollow
11 in the direction of the chuck 2 by cyclic feeding of compressed
air, then the individual workpiece passes through the zone which
is adjacent to the transition step 28 and provided with the balls
30. These balls 30 effect an alignment of the individual workpiece
8 so that the surfaces of the hexagon 10 extend aligned with those
of the non-circular region 4 of the chuck 2. In FIG. 10 the individual
workpiece 8 present between the balls 30 is indicated by dot-dash
lines. The operating region provided with the longitudinal grooves
9 has partially passed the transition step 28 and already extends
into the chuck 2 into its non-circular region 4. Due to the aligned
arrangement of the hexagon 10 and the non-circular region 4 the
undisturbed further transport of the individual workpiece 8 is established,
namely up to the stop position.
Even if, as shown in FIG. 12 the most unfavorable rotational alignment
of the individual workpiece 8 is present, the balls are first of
all displaced against spring action in radial outward direction
by the corners of the hexagon 10. The balls 30 however, upon passage
of the individual workpiece 8 produce a positive rotational alignment
of the individual workpiece 8 in that they strive to rest on the
corresponding hexagon surfaces of the hexagon 10 and thus positively
produce the rotation, as shown in FIG. 11.
Instead of the balls 30 it would also be possible to use rolling
bodies having a wall curvature in axial direction which faces the
direction of transport x of the workpiece. A corresponding spring
mounting of these roller bodies would also be possible.
The brake member formed by the balls 30 and/or the transition step
26 28 reduces the speed of the workpiece introduced into the entrance
end 12 of the feed channel 11. By the continuous action of the compressed
air on the workpiece upon its passage through the feed channel 11
the workpiece is accelerated until reaching the brake member, namely
the transition step 26 28 or the roller bodies (K). Upon reaching
the reduction in cross section, the workpiece is braked. The braking
can be effected down to a speed of zero. Without axial speed, the
workpiece then rolls in the round region of the axial hollow 11
as a result of the rotation of the latter until it lies adapted
in cross section to the non-circular region. As a result of the
continuous action of air pressure, the workpiece is then transported
further up to the stop 24. In the event that the brake member is
formed by resilient bodies K which extend into the feed channel
11 the adaptation of the angle of rotation to the position of the
workpiece can also be effected by a jamming. In such case, a soft
braking furthermore takes place. |