Parts-supply control apparatus

A part-supply apparatus provisionally holds each part delivered from a parts-passage in a temporary holding chamber having an outlet aperture before delivering the released parts to a predetermined point from the outlet aperture by means of forward movement of a supply rod capable of moving itself back and forth; wherein, in order to prevent the second parts from coming into abnormal engagement with the preceding parts at the predetermined position in the tempoary holding chamber otherwise resulting in the inability to execute normal supply of parts, a constraining device for constraining transfer of the following parts is provided in the parts-passage immediately before the outlet aperture.

FIELD OF THE INVENTION 
The present invention relates to a parts-supply control apparatus which is 
available for such a field that provisionally holds each part in a 
temporary holding chamber having an outlet aperture before externally 
delivering them by means of a supply rod. 
BACKGROUND ART 
Referring now to FIGS. 4 through 7, a conventional art is described below. 
As shown in FIGS. 6 and 7, such parts being dealt by any of parts-supply 
control apparatuses substantially comprise projection nuts. FIG. 6 
illustrates a circular nut, where the reference numeral 1 designates the 
whole aspect of a circular nut which comprises a main body 2, a tapped 
hole 3, a flange 4, and a plurality of projections 5 which are formed 
below the flange 4 and available for fusion. FIG. 4 illustrates a 
conventional apparatus which deals with such circular nuts shown in FIG. 6 
for example. A parts-supply tube 7 having rectangular section and forming 
a parts-passage 6 and a guide tube 9 of a supply rod 8 are welded together 
in the orthogonal state. A temporary holding chamber 10 is disposed in the 
orthogonal domain. An end of the parts-supply tube 7 has such a shape as 
shown in FIG. 5. Concretely, plates above and below the parts-supply tube 
7 are eliminated, whereas a pair of projective pieces 11 and 11 are formed 
on both sides, and yet, a stopper plate 12 is secured to the front edge of 
these projective pieces 11 and 11. Therefore, an outlet aperture 13 is 
formed as shown in FIG. 4. A magnet (a permanent magnet) 14 is secured to 
the stopper plate 12, where the magnet 14 attracts the nut 1 close to the 
left end of the parts-passage 6 so that it can be placed in the temporary 
holding chamber 10, where the nut 1 is provisionally held in the state 
coaxial with the supply rod 8 as shown in FIG. 4. 
The supply rod 8 comprises a large-diametric domain 15 and a guide member 
16 having diameter less than that of the large-diametric domain 15. An 
extrusive surface 17 is formed at the interface of both domains. 
FIG. 4 illustrates a nut 1 which is obliquely placed in the parts-passage 
6. Assuming that the obliquely placed nut 1 is not present in the 
parts-passage 6, operation of the above conventional apparatus is 
described below. When the supply rod 8 is driven forward by a pneumatic 
cylinder (not shown), the guide member 16 penetrates the tapped hole 3 to 
cause the extrusive surface 17 to hit against the top surface of the nut 1 
before extruding the nut 1 by overcoming the attractive force of the 
magnet 14. The extruding velocity is predetermined to be faster than the 
falling velocity of the nut 1 itself. 
Nevertheless, whenever operating the above conventional apparatus, as shown 
in FIG. 4, since the second nut projects itself out of the outlet aperture 
13, the flange of the second nut comes into engagement with the preceding 
nut in the temporary holding chamber 10 in the state obliquely being held 
below the flange of the preceding nut. In consequence, when the supply rod 
8 thrusts itself, the nut in the temporary holding chamber 10 is locked to 
obstruct execution of smooth delivery of the preceding nut. The same 
problem also occurs whenever dealing with a square projection nut having 
four fusible projections in four corners as shown in FIG. 7. The same 
problem also occurs even when dealing with flatly shaped parts. 
DISCLOSURE OF THE INVENTION 
Therefore, the invention has been provided in order to solve the above 
problem. The invention is characterized by provision of a constraining 
means for constraining movement of parts held in a parts-passage at a 
position immediately before an outlet aperture of this passage before 
externally delivering each part from the outlet aperture by means of a 
supply rod. Owing to the retention of each part, the apparatus prevents 
the second parts from interfering with the first parts by way of 
projecting itself from the outlet aperture. 
According to the invention, since individual parts are constrained from 
moving themselves through a parts-passage immediately before the outlet 
aperture, there is no probability of causing the first and second parts to 
come into engagement with each other in such an abnormal state mentioned 
earlier, and therefore, the apparatus can implement highly reliable and 
smooth supply of parts.

OPTIMAL FORM FOR EMBODYING THE INVENTION 
Structures identical to those which are explained in reference to FIGS. 4 
through 7 are designated by identical reference numerals in the 
accompanying drawings, and thus, detailed description of these are deleted 
from the following description. 
First, an embodiment of the invention shown in FIG. 1 is described below. A 
pneumatic cylinder 19 is linked with the top end of a guide tube 9. The 
piston rod of the pneumatic cylinder 19 makes up a large-diametrical 
domain 15 and drives a supply rod 8 in the forward and backward 
directions. Nut 1 is delivered to a steel-plate parts 21 which is placed 
on a stationary electrode 20, where a guide pin 22 of the stationary 
electrode is arranged to coincide with the nut 1 by way of penetrating the 
steel-plate parts 21. Two-dot chained lines respectively designate the 
state in which the thrusted supply rod 8 executes supply of nuts. 
In order to constrain transfer of the nut 1 immediately before an outlet 
aperture 13 in a parts-passage 6, a constraining means 23 is provided. A 
variety of systems may be taken into consideration to materialize this 
constraining means 23. However, the invention introduces a system which 
causes a constraining pin 24 to thrust through a tapped hole 3 of the nut. 
Concretely, a pneumatic cylinder 25 is secured to the top surface of a 
parts-supply tube 7, where the piston rod of this pneumatic cylinder 25 
makes up a constraining pin 24. The constraining pin 24 thrusts and 
retreats itself into and out of the parts-supply tube 7 via a through-hole 
26 which penetrates the parts-supply tube 7. The reference numerals 27 and 
28 respectively designate air-supply tubes for supplying air to the 
pneumatic cylinder 25. 
When the first nut is positioned in a temporary holding chamber 10 and then 
the second nut just arrives at a position right below the constraining pin 
24 which is in the retreating condition, the constraining pin 24 thrusts 
into the tapped hole 3 to prevent the second nut from transferring itself. 
Next, another embodiment shown in FIG. 2 is described below. This 
embodiment introduces a system which presses the second nut against the 
inner surface of the parts-supply tube 7. A pressing piece 29 is combined 
with the piston rod of the pneumatic cylinder 25. 
In the course of operating the pressing system shown in FIG. 2, while the 
nut 1 has not yet arrived at the inner surface of the parts-supply tube 7, 
transferring amount of the pressing piece 29 increases. The system 
confirms the presence or absence of the nut 1 by way of detecting the 
increase of the transferring amount of the pressing piece 29. In 
consequence, the system can prevent abnormal operation from occurrence. In 
addition to the method of depressing the nut 1 from the top, the nut 1 may 
also be pressed from a lateral side. 
Another embodiment of the invention shown in FIG. 3 is described below. 
This embodiment provides a varied example of a double-structured supply 
rod 8 provided inside of a guide tube 9. Concretely, the supply rod 8 
comprises a hollow shaft 30 and an inner shaft 31 which is slidably 
inserted in this hollow shaft 30. A magnet (a permanent magnet) is built 
in the tip domain of the inner shaft 31 and covered with a covering plate 
33. When the standby mode shown in FIG. 3 is underway, bottom ends of both 
shafts 30 and 31 make up a single plane that can tightly be adhered to the 
top surface of the nut 1. 
As soon as the nut 1 arrives at the predetermined position after causing 
the supply rod 8 to thrust itself in the state shown in FIG. 3, the supply 
rod 8 halts its own movement. In succession, only the inner shaft 31 is 
forcibly drawn back to cause the magnet 32 to leave the nut 1. As a 
result, the nut 1 falls onto the opposite member, thus completing supply 
of an individual parts. Since the mechanism for forcibly drawing only the 
inner shaft 31 backward can easily be implemented by applying any 
conventional method, further description of this mechanism is deleted here 
.