Rivet supplying apparatus

An apparatus for supplying a blind rivet to a riveting device includes a rivet supplying conduit through which the rivet is supplied, a guide member to which a nose of the riveting device is moved from the workpiece, a rivet holder element for receiving the rivet, and a piston-cylinder unit for transporting the rivet holder element. The piston-cylinder unit operates to transport the rivet holder element from a position in which the rivet from the supplying conduit is received in the holder element to a position in which the nose of the riveting device approaches the holder element and holds a mandrel of the rivet.

BACKGROUND OF THE INVENTION 
The present invention relates to a rivet supplying apparatus, and more 
particularly to a rivet supplying apparatus for supplying a blind rivet to 
a riveting device from a rivet feeder. 
A rivet feeder is known in which the rivets are fed one by one in an 
orientated manner. The rivet from the rivet feeder is manually set into 
the nose of a riveting device, e.g. a handy rivet gun or an air rivet gun. 
Such manual operation, however, is one of the main factors which prevent 
the improvement of the efficiency in the riveting work. 
Accordingly, various proposals have been made to eliminate the manual rivet 
supplying operation from the riveting work. For example, in an automatic 
rivet supplying apparatus as disclosed in the Japanese Utility Model 
Laid-open Publication No. 146181/78, the nose of riveting device is so 
disposed with respect to the supplying apparatus that the axis of the nose 
of the riveting device aligns with the axis of one end portion of a rivet 
supplying conduit. The nose of the riveting device urges guide means 
towards a limit switch for permitting the rivet supplying. The above 
mentioned rivet supplying apparatus can supply rivets sequentially to the 
riveting device nose without manual operation. However, since the mandrel 
of the rivet leads the rivet body within the supplying passage in the 
apparatus, the rivet may be caught in the supplying passage. Accordingly 
the riveting work is often interrupted to re-set or remove the caught 
rivet from the supplying passage. 
Furthermore, the positioning of the rivet relative to the nose of the 
riveting device is conducted via the mandrel of the rivet. In order to 
supply the rivets having various sizes to the riveting device, it is 
necessary to prepare some separate apparatus appropriate to the respective 
rivet sizes (i.e., mandrel sizes), or to prepare some replaceable or 
detachable guide means for the respective rivet sizes. Such replacement, 
however, also interrupts the riveting operation with the result that the 
efficiency of the riveting work is further degraded. 
Moreover, the spring coils are used for rivet guidance which may change 
with passage of time, so that periodic inspection and maintenance must be 
required. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a rivet 
supplying apparatus which has a lower possibility of occurence of a rivet 
clog. 
Another object of the invention is to provide a rivet supplying apparatus 
having a shorter MTTR (Mean Time To Repair) and a longer MTBF (Mean Time 
Between Failures). 
The above and other objects and features of the invention will be apparent 
from the following description of the preferred embodiments in connection 
with the accompany drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring first to FIG. 1, a robot 1 operates to transport a riveting 
machine 2 between a rivet supplying apparatus 3 according to the invention 
and a workpiece 4 on a table 5. The robot 1 includes a swingable arm 6 
which is provided at the distal end thereof with the riveting machine 2. A 
nose 7 of the riveting machine 2 holds a blind rivet from the rivet 
supplying apparatus 3 and thereafter is transported to a space above the 
workpiece 4 by means of the swing motion of the arm 6 (Arrow A). The 
riveting machine 2 is moved downwardly to insert the rivet into the rivet 
hole formed in the work 4 to be riveted and conducts the riveting 
operation. The term "blind rivet" appearing throughout the present 
application refers to a rivet having a hollow body, and a mandrel which 
extends through the hollow body and one end of which is enlarged. In the 
riveting work, a rivet head is urged onto the hole formed in the elements 
to be riveted and the other end portion of the mandrel of the rivet is 
pulled until the mandrel is broken. Accordingly, one end portion of the 
rivet body opposite to the rivet head is deformed by the enlarged end of 
the mandrel, so that the elements are joined together between the rivet 
head and the deformed end portion. 
The rivets are fed from a rivet feeder 8 to the rivet supplying apparatus 3 
in an orientated manner so that the rivet body leads the rivet mandrel. 
The rivet feeder 8 includes a container 9 for containing the mandrel type 
blind rivets, escapement 10, and a passage 11 through which the orientated 
rivets pass from the container to the escapement 10. 
The rivets from the escapement 10 of the rivet feeder 8 pass through a 
rivet supplying conduit 12, i.e. air shooter. The conduit 12 is connected 
at one end thereof to the escapement 10 and the other end portion 13 of 
the conduit 12 remains stationary relative to a base 15 through an 
attachment 14 fixed to the base 15. 
As will be clearly seen from FIGS. 1 and 2, a gate shaped guide member 16 
adjacent to the attachment 14 is fixed to the base 15. The nose 7 of the 
riveting machine 2 is first moved downwardly, along an approach line 
parallel to an axis of the end portion 13 of the conduit 12, to approach a 
hole 17 formed in a cross bar 18 of the guide member 16. There is a 
piston-cylinder unit 19 on the base 15, which operates to reciprocate a 
rivet holder element 20 attached to a piston 21 of the unit 19. The rivet 
holder element 20 is provided with a hole 22. The piston-cylinder unit 19 
operates to reciprocate the rivet holder element 20 along a drive line 
perpendicular to the axis of the end portion 13 of the conduit 12 so that 
an axis of the hole 22 aligns with the axis of the end portion 13 of the 
conduit 12 as well as with the nose approach line. 
The operation of the above mentioned supplying apparatus will be described 
hereinunder with referring to FIGS. 2 to 5. The blind rivet 23 has a body 
24 and a mandrel 25. The rivet 23 is supplied in the conduit 12 one by one 
by means of the pneumatic pressure so that the rivet body 24 leads the 
mandrel 25. The rivet 23 from the conduit 12 is received at the rivet body 
24 in the hole 22 of the rivet holder element 20 through a communication 
opening 27 formed in the attachment 14 (FIG. 3). When the photo-sensor 
(not shown) detects safe receipt of the rivet on the hole 22, a control 
unit (not shown) operates to drive the piston-cylinder unit 19 to 
transport the rivet holder element 20 along the drive line through an 
opening 26 of the attachment 14. The attachment 14 is provided with a slit 
28 through which the rivet mandrel 25 passes. At the moment the axis of 
the hole 22 of the rivet holder element 20 aligns with the approach line 
of the nose 7 during the transportation, i.e. a chuck of the nose 7 aligns 
with the mandrel 25 of the rivet 23, another photo-sensor (not shown) 
detects such alignment and delivers a signal to the control unit. The 
control unit operates to stop the piston-cylinder unit 19 from driving 
upon receipt of the signal from the photo-sensor (FIG. 4). 
Sequentially, the nose 7 moves downwardly to the mandrel 25 of the rivet 23 
along the approach line through the hole 17 in the guide member 16 and 
holds the mandrel 25 (FIG. 5). A negative pressure may be applied to the 
nose 7. If a safe holding of the mandrel 25 of the rivet 23 is once 
detected, the nose 7 is moved upwardly and transported towards the 
workpiece 4 (FIG. 1). Simultaneously, the piston-cylinder unit 19 operates 
to pull back the rivet holder element 20 to an original position in order 
to receive a new rivet (FIG. 2). The above process is repeated. 
FIGS. 6 and 7 show the second and the third embodiments of the invention. 
In the following description of the embodiments taken in connection with 
the accompanying drawings, like parts and parts for the same purpose in 
the drawings are identified by the same reference numerals. In the second 
and the third embodiments, the drive line along which the rivet holder 
element 20 reciprocates is parallel to the base portion 15, but inclined 
to an axis of the end portion 13 of the rivet supplying conduit 12. 
However, the axis of the end portion 13 and the approach line are parallel 
to each other. The rivet holder element is so moved that an axis of the 
hole 22 is parallel to the approach line. The operations of these 
embodiments are substantially the same as that of the first embodiment. 
FIG. 8 shows the fourth embodiment of the invention. In this embodiment, 
the attachment 14 and the guide member 16 are spaced laterally from each 
other. The attachment 14 and the guide member 16 are so fixed on the base 
portion 15 that the axis L.sub.1 of the end portion 13 of the conduit 12 
and the approach line L.sub.2 of the nose 7 are spaced at an angle .theta. 
from each other. 
The operation of the rivet supplying apparatus shown in FIG. 8 will be 
described hereinunder. The rivet 33 is supplied within the conduit 12 by 
means of the pneumatic pressure. The rivet 23 from the end portion 13 is 
received at the body 24 thereof in the hole 22 of the rivet holder element 
20 through the opening 27 of the attachment 14. When safe receipt of the 
rivet body 24 on the hole 22 is detected, the rivet holder element 20 is 
so rotated about an axis of the piston 21 in a direction of the arrow B by 
an angle .theta. by means of the piston-cylinder unit 19 that the axis 
L.sub.3 of the hole 22 of the rivet holder element 20 becomes parallel to 
the approach line L.sub.2 of the nose 7. Sequentially the piston 21 is 
driven axially to pull the rivet holder element 20 so as to make the axis 
L.sub.3 of the hole 22 align with the approach line L.sub.2 of the nose 7. 
When the alignment between the axis L.sub.3 and the approach line L.sub.2 
is detected, the nose 7 is moved downwardly, along the approach line 
L.sub.2 through the hole 17 formed in a free arm of L-shaped guide member 
16, to the rivet 23 and holds the mandrel 25 thereof. After the holding of 
the mandrel of the rivet, the nose 7 is moved upwardly and then is 
transported to the work. Simultaneously the piston 21 is inversely axially 
driven to push the rivet holder element 20 and is driven to rotate the 
rivet holder element 20 conterclockwise by the angle .theta. so as to make 
the axis L.sub.3 align with the axis of L.sub.1 in order to receive a new 
rivet. 
FIG. 9 shows the fifth embodiment of the present invention. In this 
embodiment, the piston-cylinder unit 19 is fixed on a ceiling 15'. The 
attachment 14 and the guide member 16 are also fixed on the ceiling 15'. 
The operation of the embodiment shown in FIG. 9 wll be described 
hereinunder. The rivet 23 is thrust upwardly within the conduit 12 by 
means of the pneumatic pressure. The rivet 23 is sucked up and received at 
the body 24 thereof in the recess 22 formed in the rivet holder element 20 
by means of the negative pressure which is applied to a bottom of the 
recess 22 through a flexible tube 29. When the safe receipt of the rivet 
23 in the recess 22 is detected, the piston-cylinder unit 19 is driven to 
transport the rivet holder element 20 towards the guide member 16 so that 
the axis of the recess 22, i.e. the mandrel 25 of the rivet 23, aligns 
with the approach line of the nose 7, i.e. the chuck of the nose 7. When 
the alignment between the axis of the recess 22 and the approach line of 
the nose 7 is detected, the nose 7 is moved upwardly to approach the rivet 
mandrel 25 through the hole 17 in the guide member 16. Simultaneously, the 
application of negative pressure to the recess 22 is suspended and the 
nose 7 holds the mandrel 25. Sequentially the nose 7 is transported 
towards the workpiece. To the contrary, the piston-cylinder unit 19 
operates to pull back the rivet holder element 20 so that the axis of the 
recess 22 aligns with the axis of the end portion 13 of the conduit 12. 
Sequentially the negative pressure is applied to the recess 22 again and 
then the preparation for receiving a new rivet is completed. 
FIG. 10 shows the sixth embodiment of the present invention. In this 
embodiment, two rivet supplying conduits 12 and 30 remain stationary 
relative to the base portion 15 via the attachment 32. The piston-cylinder 
unit 19 is so controlled that the rivet holder element 20 can receive the 
rivet from the selected conduit 12 or 30. The operation of the apparatus 
is substantially the same as the one of the first embodiment. Rivets of a 
different size may pass through the conduits 12 and 30, respectively. The 
rivet holder element 20 can be provided with a plurality of holes the 
number of which corresponds with the number of the conduits. Furthermore, 
three or more conduits may be provided in the apparatus. 
In compliance with the demands for the mounting location, the mounting 
condition, or the required operation of the apparatus, it is possible to 
select an appropriate embodiment among the above mentioned ones. In the 
above mentioned embodiments except the fifth embodiment, it is possible to 
apply the negative pressure to the hole 22 of the rivet holder element 20 
so as to receive the rivet more surely, if necessary. 
As described above, the process of rivet supplying can be conducted under 
sequence control using the sensing means and the control unit. To the 
contrary, it is possible to conduct the process of rivet supplying 
manually step by step.