U.S. patent number RE35,914 [Application Number 08/738,295] was granted by the patent office on 1998-10-06 for parts feeding device.
Invention is credited to Yoshitaka Aoyama.
United States Patent |
RE35,914 |
Aoyama |
October 6, 1998 |
Parts feeding device
Abstract
A part is kept on standby so that it can be reliably held by a
feed rod. An auxiliary feed rod is provided with an arrangement for
holding a part at a fixed position in advance. The part is stopped
on the advance and retraction axis of a main feed rod by the
advance movement of the auxiliary feed rod where the part
transferred and is held on the main feed rod.
Inventors: |
Aoyama; Yoshitaka (Sakai-shi,
Osaka 590-01, JP) |
Family
ID: |
14631225 |
Appl.
No.: |
08/738,295 |
Filed: |
October 25, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
837889 |
Feb 20, 1992 |
05359171 |
Oct 25, 1994 |
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Foreign Application Priority Data
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Feb 23, 1991 [JP] |
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3-114181 |
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Current U.S.
Class: |
219/93; 221/212;
221/262 |
Current CPC
Class: |
B25B
23/10 (20130101); B23K 9/206 (20130101); B23P
19/006 (20130101); B25B 23/12 (20130101) |
Current International
Class: |
B23K
9/20 (20060101); B23P 19/00 (20060101); B23K
011/14 (); B23Q 007/04 () |
Field of
Search: |
;219/86.24,86.25,86.7,86.8,93,119,120
;221/212,239,262,211,186,187,188,189,190 ;29/743,744 ;81/125 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2446137 |
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Jun 1980 |
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DE |
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144222 |
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Oct 1980 |
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DE |
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3726579 |
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Feb 1989 |
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DE |
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60-99490 |
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Jun 1985 |
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JP |
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1-266974 |
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Oct 1989 |
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JP |
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3-210976 |
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Sep 1991 |
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JP |
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2225974 |
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Jun 1990 |
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GB |
|
2244445 |
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Apr 1991 |
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GB |
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Primary Examiner: Evans; Geoffrey S.
Attorney, Agent or Firm: Pollock, Vande Sande &
Priddy
Claims
What is claimed is:
1. A parts feeding apparatus comprising:
a main feed rod reciprocating along a first axis and having a
recess formed therein for receiving a part delivered to a transfer
point along the first axis;
an auxiliary feed rod reciprocating within a sleeve along a second
axis, which intersects the first axis, and forms an acute angle
therewith;
means for supplying the part to a preselected pickup point along
the second axis;
means fixed to an outward end of the auxiliary feed rod, for
removably retaining the part, when the outward end is displaced to
the pickup point;
.[.means for connecting the sleeve to the part supplying
means;.].
means for .[.jointly.]. displacing the sleeve .[.and part supplying
means.]. along a direction parallel with the first axis;
means for extending the auxiliary rod relative to the sleeve, along
the second axis, until the part is located at the transfer point
along the first axis;
.[.means for displacing the main feed rod to achieve engagement of
the part by the main feed rod at the transfer point along the first
axis;.]. and
means located in the recess of the main feed rod for releasably
retaining the part .[.while the displacing mean continues movement
of the retained part beyond the engagement point.]..
2. The apparatus set forth in claim 1 wherein the main feed rod is
an electrode of a projection welding machine.
3. The apparatus set forth in claim 1 wherein the means fixed to an
outward end of the auxiliary feed rod for removably retaining the
part, includes a magnet.
4. The apparatus set forth in claim 1 wherein the means located in
the recess of the main feed rod for releasably retaining the part
is a magnet.
Description
BACKGROUND OF THE INVENTION
As for a prior art, there is an advance and retraction type feed
rod, which is provided at its front end with parts holding means
comprising a hole or chuck mechanism, said rod including a
mechanism disposed on the axis thereof for temporarily locking a
part, such as a bolt, coming from a parts feeder or the like, said
rod being advanced toward said part in the locked state and, with
said holding means holding the part, conveying the part to an
intended place.
According to the prior art described above, a single mechanism has
to perform two functions at the same time; first, it has to stop a
part conveyed from a parts feeder or the like-through a feed hose
and must be stopped accurately on the axis of the feed rod, and
second, the stopped position must be reliably maintained.
Therefore, such mechanism is necessarily of high precision, and
even a slight decrease in precision would upset the correct
engagement between the holding means of the feed rod and a part,
causing the problem of the part falling off. Further, if the
mechanism for temporarily locking a part is present on the axis of
the feed rod all the time, this limits the installation space
therefor to a great extent, and hence the device is increased in
size, making it difficult to install it in a narrow space.
SUMMARY OF THE INVENTION
The present invention has been presented to solve the problems
described above, and the invention is characterized in that
disposed on the advance and retraction axis of a main feed rod
adapted to advance and retract is an auxiliary feed rod, said main
feed rod being formed with a parts receiving hole, said auxiliary
feed rod having attached thereto means for holding a part at a
fixed position, said main feed rod being provided with means for
holding a part positioned by the auxiliary feed rod when the latter
is advanced. It is arranged so that a part is held in advance at a
fixed position in the auxiliary feed rod, and the auxiliary feed
rod is advanced until the part stops on the advance and retraction
axis of the main feed rod, then either the main feed rod is
advanced thereto or the auxiliary feed rod is moved toward the main
feed rod, whereby the part is held by the main feed rod, and in
this state the main feed rod is advanced to convey the part to an
intended place.
The main feed rod is a movable electrode for a projection welding
machine. It is arranged so that the main feed rod holding a part is
advanced to reach an intended place, whereupon an electric current
is passed to effect welding. The advance and retraction axis of the
main feed rod crosses the advance and retraction axis of the
auxiliary feed rod at an acute angle. It is arranged that the
auxiliary feed rod is obliquely advanced to convey a part onto the
advance and retraction axis of the main feed rod. Either or both of
the means of the auxiliary feed rod for holding a part at a fixed
position and the means of the main feed rod for holding a part are
provided with magnets. The attractive forces of the magnets enable
the respective functions to be performed. An arrangement is added
whereby either the auxiliary feed rod alone or both the auxiliary
feed rod and a parts feeding tube are adapted to advance and
retract along the advance and retraction axis of the main feed rod.
A part held at a fixed position on the auxiliary feed rod is
transferred to the main feed rod and held there. A driving
mechanism is provided so that after a part has been inserted into a
parts receiving hole either by the movement of the auxiliary feed
rod along the advance and retraction axis of the main feed rod or
by the advance movement of the main feed rod, the auxiliary feed
rod is moved away from the advance and retraction axis of the main
feed rod. When a part is inserted into the receiving hole, the
auxiliary feed rod is moved, e.g., horizontally, from that position
so as to hasten the start of the main feed rod.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view, partly in longitudinal section, showing an
entire device:
FIG. 2 is a plan view of a support plate;
FIG. 3 is a front view of a parts feeding tube;
FIG. 4 is a side view showing another embodiment;
FIG. 5 is a side view, in longitudinal section, of an auxiliary
feed rod wherein an electromagnet is utilized;
FIG. 6 is a side view, in longitudinal section, showing a modified
example of a main feed rod;
FIG. 7 is a side view, in longitudinal section, of a main feed rod
wherein an electromagnet is utilized;
FIG. 8 is a plan view of a support plate;
FIG. 9 is a side view, in longitudinal section, showing a modified
example of a main feed rod;
FIG. 10 is a side view, in longitudinal section, showing a modified
example of an auxiliary feed rod;
FIG. 11 is a side view in longitudinal section, wherein the advance
and retraction axes of the main and auxiliary feed rods are
orthogonal to each other; and
FIG. 12 is a side view wherein the main feed rod is a movable
electrode for a projection welding machine.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First, an embodiment shown in FIGS. 1 through 3 will be described.
A pliable part feeding hose 1 extending from a parts feeder (not
shown) is connected to a parts feeding tube 2. A guide tube 4 is
welded to a bracket 3 welded to the parts feeding tube 2, and an
auxiliary feed rod 5 extends through said guide tube 4 so that it
is free to advance and retract. The auxiliary feed rod 5 is
advanced and retracted by an air cylinder 6 connected to the guide
tube 4. An air cylinder 7 is firmly fixed to a stationary member 8,
with its piston rod 9 joined to the bracket 3, enabling the parts
feeding tube 2 and auxiliary feed rod 5 to advance and retract as a
unit, the direction of advance and retraction thereof being
parallel with the advance and retraction axis of the main feed
rod.
The auxiliary feed rod 5 is provided with means 11 for holding a
part 10 at a fixed position. The part 10 in this case is a
projection bolt comprising a stem portion 12, a flange 13 and
projections 14 for welding. Various forms may be thought of as said
means 11, but herein illustrated is a magnet 16 built in a support
plate 15 integral with the auxiliary feed rod 5. The auxiliary feed
rod 5 is inclined at about 45 degrees with respect to the vertical
line, as shown, and the support plate 15 is horizontally installed.
A recess 17 formed in the support plate 15 is opened at the right
side, as shown in FIGS. 1 and 2, and has an arcuate portion 18 at
the left side adapted to coincide with the circular flange 13.
Further, the support plate 15 has a magnet 16 embedded therein at a
position deviated toward the arcuate portion 18, thereby ensuring
that the outer periphery of the flange 13 exactly coincides with
the arcuate portion 18. In addition, the magnet 16 in this case is
a permanent magnet, and in order to enable its magnetic force to
act on the part 10 more strongly, the auxiliary feed rod 5, support
plate 15 and parts feeding tube 2 are made of stainless steel. The
parts feeding tube 2 is formed with a notch 19 to allow the stem
portion 12 to pass therethrough.
The main feed rod 20 is joined to the piston rod 22 of an air
cylinder 21 firmly fixed to the stationary member 8. The advance
and retraction axis 23 of the main feed rod 20 is vertically
disposed, crossing the advance and retraction axis 24 of the
auxiliary feed rod 5 at an acute angle. The main feed rod 20 is
formed with a parts receiving means 26, which in this case is a
magnet (permanent magnet) 27 fixed in the innermost region of the
receiving hole 25, as shown.
A mating part 28 has a recess 29 and the part 10 is inserted in the
recess 29, i.e.. the intended place. In addition, air hoses for
operating air are connected to the air cylinders but they are
omitted from illustration, and sensors and air switching control
valves for sequence operation employed therein are known and hence
a description thereof is omitted.
The operation of the above embodiment will now be described. FIG. 1
shows the main and auxiliary feed rods 20 and 5 at their standby
positions which are the most retracted positions. When a part 10 is
fed to the parts feeding tube 2, its flange fits in the recess 17
as it is attracted by the magnet 16 until the outer peripheral
surface of the flange 13 exactly coincides with the arcuate portion
18. Thereby, it is correctly positioned on the support plate 15,
with the result that the part 10 is held at the fixed position on
the auxiliary feed rod 5. Then, the auxiliary feed rod 5 is
advanced until the stem portion 12 of the part 10 coincides with
the advance and retraction axis 23, whereupon the air cylinder 7 is
actuated to move the auxiliary feed rod 5 upward; therefore, the
stem portion 12 enters the receiving hole 25, with the part 10 held
on the main feed rod 20. Thereafter, the auxiliary feed rod 5 is
moved downward, retracted rearwardly upward, and returned to the
position shown in FIG. 1. Then, the main feed rod 20 is moved
downward until the flange 13 is pushed in to the recess 29,
whereupon the feeding of a part is completed, with the main feed
rod 20 returning to the solid line position. In addition, the
attractive force of the magnet 27 is set at a value greater than
the attractive force of the magnet 16, so that when the auxiliary
feed rod 5 is moved downward, the part 10 remains in the receiving
hole 25. Further, though not shown, the parts feeding tube 2 may be
fixed to the stationary member, with the auxiliary feed rod 5 alone
being adapted to be advanced and retracted along the advance and
retraction axis by the air cylinder 7.
An embodiment shown in FIG. 4 is designed so that when a part 10 is
inserted into the receiving hole 25, the auxiliary feed rod 5 is
moved from that position as indicated by an arrow 30 to hasten the
time of advance of the main feed rod 20 even a little. When it is
moved in the direction of the arrow 30, the flange 13 leaves the
recess 17 at its open side. To obtain such movement in the
direction of arrow 30, there is provided an air cylinder 31 fixed
to the stationary member 8 and its piston 32 is adapted to move in
parallel with the arrow 30 and is fixed to the air cylinder 7
through a connector 33. In addition, the arrows 34 and 35 indicate
the same directions of movement as described above.
FIG. 5 shows the use of an electromagnet in the place of the magnet
16 of FIG. 1. The auxiliary feed rod 5 extends through a solenoid
36, said rod 5 being made of iron, which is a magnetic material,
while the guide tube 4 will suitably be made of stainless
steel.
FIG. 6 shows a slot 37 formed in the main feed rod to allow the
stem portion 12 of a part to pass therethrough. This arrangement
decreases the distance of upward travel of the auxiliary feed rod 5
even a little and shortens the processing time.
FIG. 7 shows the use of an electromagnet in the place of the magnet
27 of FIG. 1. The main feed rod 20 extends through a solenoid 38,
said rod being made of magnetic material, and a part 10 entering
the receiving hole 25 is held by the electromagnet.
FIG. 8 shows a modified example of means installed on the auxiliary
feed rod for holding a part at a fixed position, wherein balls 39
are exposed from the recess 17 as they are urged by coil springs
40. Therefore, since the flange 13 is subjected to the elastic
force from the balls 39 on its outer periphery, it closely contacts
the arcuate portion 18, whereby positioning is effected.
FIG. 9 shows a modified example of means installed on the main feed
rod for holding a part, wherein a plate spring 41 is fixed in the
receiving hole 25 to thereby hold the stem portion 12.
FIG. 10 shows a magnet 16 embedded in the auxiliary feed rod 5.
When the magnetic force on a part is to be nullified, the position
of the magnet 16 is shifted. That is, the auxiliary feed rod 5
comprises an outer shaft 42 and an inner shaft 43 adapted to be
reciprocated therein, and the magnet 16 is joined to the front end
of the inner shaft 43, said magnet 16 being positioned in a support
plate 15 (having a recess 17 and an arcuate portion 18 similar to
those mentioned above) welded to the outer shaft 42. The auxiliary
feed rod 5 is received in an outer sleeve 44, as shown, and a
control pin 45 fixed to the inner shaft 43 extends through an
elongated opening 46 formed in the outer shaft 42 to extend in the
stroke direction. On the other hand, the outer peripheral surface
of the outer sleeve 44 has an air cylinder 47 fixed thereto, the
piston rod 48 thereof having an engaging element 49 joined thereto.
The engaging element 49 projects into the outer sleeve 44 through
an elongated opening 50 formed in the outer sleeve 44 to extend in
the stroke direction. The amount of projection of this engaging
element 49 is such that when the auxiliary feed rod 5 is advanced
by a predetermined amount, the control pin 45 is stopped a little
short of the engaging element 49. In addition, an air cylinder 51
is joined to the end of the outer sleeve 44, with its piston rod 52
connected to the end of the outer shaft 42. Further, a coil spring
53 is installed in the outer shaft 42 and its elastic force is
limited by the control pin 45 abutting against the lower side of
the elongated opening 46.
The operation of the device shown in FIG. 10 will now be described.
When the positioning of the part 10 on the support plate 15 is
effected by the magnet 16, the auxiliary feed rod 5 is advanced and
stopped in the same manner as in FIG. 1. and is moved upward along
the advance and retraction axis of the main feed rod, with the step
portion 12 entering the receiving hole 25. Thereafter, when the
engaging element 49 is raised by the action of the air cylinder 47,
the displacement thereof is transmitted to the magnet 16 through
the inner shaft 43, whereby the magnet 16 is moved away from the
part 10; thus, the task of holding of the part 10 is transferred to
the main feed rod. In addition, the advance movement of the main
feed rod 20 may be a two-step motion; at the first stroke the stem
portion 12 enters the receiving hole 25 and then, after the support
plate 15 is retracted, the advance stroke at the second step is
effected.
Such can also be employed in FIG. 1, and in the case of FIG. 4, the
invention can be embodied without involving the upward displacement
indicated by the arrow 35.
FIG. 11 shows an arrangement wherein the advance and retraction
axes 23 and 24 of the main and the auxiliary feed rods 20 and 5 are
orthogonal to each other and hence the installation direction of
the air cylinder is set to coincides therewith.
FIG. 12 horizontally indicates the main feed rod 20 which in this
case is the movable electrode of a projection welding machine. An
electrode tip 54 is connected to the main feed rod 20 shown in
phantom lines, said tip 54 being provided with a receiving hole 25
and a magnet 26.
According to the invention, since the part is held in advance at a
fixed position on the auxiliary feed rod, the relative positions of
the auxiliary feed rod and the part are established and since, in
this held state, the part is stopped on the advance and retraction
axis of the main feed rod, the part is always accurately set on the
advance and retraction axis main feed rod. Therefore, there is no
need to simultaneously effect the holding and positioning of a part
fed onto the axis of the feed rod through a feed hose by a single
mechanism, as described in the paragraph of the prior art; thus,
the initial positioning on the advance and retraction axis of the
main feed rod, which forms the basis of the operation, can be
accurately effected.
In that the device having the effects described above is employed
as a movable electrode for a projection welding machine, the
welding of projection bolts can be completed at the same time as
they are fed to a mating iron sheet or the like, a fact which is
effective from the standpoint of productivity.
Since the advance and retraction axes of the main and auxiliary
feed rods cross each other at an acute angle, the auxiliary feed
rod can be advanced from an oblique direction so that the device
can be effectively employed even in an environment where the
peripherals are intricate.
Further, since the holding capacity is imparted to both rods or to
one of them by using a magnet, the holding means is compact.
Further, in the case where the main feed rod is an electrode for
projection welding, a permanent magnet is disposed in the innermost
region of the receiving hole and hence the amount of heat
transmitted to the magnet is minimized, so that thermal effects on
the magnet can be avoided.
Since either the auxiliary feed rod alone or both said rod and the
parts feeding rod can be advanced and retracted along the advance
and retraction axis of the main feed rod, the part positioned on
said advance and retraction axis can be smoothly inserted into the
receiving hole in the main feed rod.
Since the driving mechanism is designed so that as the auxiliary
feed rod is moved upward or downward, the part is advanced into the
receiving hole in the main feed rod and the auxiliary feed rod is
moved away from the advance and retraction axis of the main feed
rod, it is possible to hasten the start of operation of the main
feed rod, a fact which is effective for increasing
productivity.
* * * * *