Apparatus for aligning a parison with a blow mold

Apparatus includes a blow mold for forming a blown article from a parison and a rotatable mandrel for holding a parison to be blown. The apparatus provides for moving the mandrel and parison into the blow mold, locating the mandrel and parison thereon into alignment with the blow mold and maintaining the alignment in the blow mold.

BACKGROUND OF THE INVENTION 
The reheat and stretch blow molding of plastic preforms or parisons 
sometimes requires that the preform be specifically located in relation to 
the blow mold so that the shape of the blown article is accurately 
registered. For example, the neck finish of the preform should desirably 
be properly located in relation to the blow mold, especially for 
non-symmetrical preforms, so that the shape of the blown article is 
correctly registered in relation to the neck finish, or thread start 
and/or finish portion of the article. 
The apparatus described in U.S. Pat. No. 4,690,633 carries preforms on 
pallets from a loading station to a finishing or blowing station via a 
conditioning station. The preform is blown at the blowing station and then 
the blown article moved to an unloading station. Preforms of 
non-symmetrical shape can be transported by the pallets in this device; 
however, the preform must be properly positioned immediately prior to the 
blowing stage and the positioning must be maintained in the blowing stage 
so that the body shape of the blown article is correctly registered. In 
the above apparatus, the preforms are correctly located at the loading 
station since the preforms are removed from the injection molds using a 
robot and take off plate which directly places the preforms onto the 
mandrels in the loading station. Thereafter, the preform is firmly held by 
the mandrel throughout the preform's passage through the device. However, 
the mandrels spin during their passage through the conditioning station in 
order to impart the desired temperature conditions and this spinning 
changes the orientation of the preforms. 
It is therefore, an object of the present invention to provide an apparatus 
which properly positions the preform prior to blowing and maintains the 
correct positioning at the blow station. 
It is a still further object of the present invention to provide an 
apparatus as aforesaid which is suitable for use with non-symmetrical 
preforms and which is suitable for use with preforms held on mandrels 
which spin during a temperature conditioning cycle. 
Further objects and advantages of the present invention will appear 
hereinbelow. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, it has now been found that the 
foregoing objects and advantages can be readily obtained. The apparatus of 
the present invention aligns a parison with the blow mold and maintains 
the alignment in the blow mold. The apparatus comprises: a blow mold for 
forming a blown article from a parison; a mandrel, generally rotatable, 
for holding the parison to be blown; means for moving the mandrel and 
parison into the blow mold; and location means for moving the mandrel and 
parison thereon into alignment with the blow mold and including means for 
maintaining the alignment in the blow mold. The mandrel preferably 
includes a flat plate with a projection thereon for holding the parison. 
An eccentric cam preferably is connected to the plate and depends 
therefrom. A movable arm is engageable with the cam upstream of the blow 
mold wherein the arm rotates the cam and mandrel into alignment with the 
blow mold. 
The flat plate includes a notch. A dog is provided upstream of the blow 
mold wherein the dog engages the notch when the mandrel is properly 
aligned with the blow mold and maintains the engagement and alignment in 
the blow mold so that the parison maintains its alignment in the blow 
mold. 
In addition, the plate includes a flat portion opposed to the notch and an 
alignment block is provided upstream of the blow mold. In accordance with 
the present invention, when the flat portion is aligned with the alignment 
block by the location means the mandrel is permitted to pas the alignment 
block. At the same time, the notch and dog are engaged assuring that the 
alignment will be maintained in the blow mold. 
The apparatus of the present invention is particularly suitable for use 
with non-symmetrical parisons and assures correct alignment despite the 
use of rotatable mandrels. 
In the preferred embodiment, a conditioning means is provided upstream of 
the blow mold for conditioning the temperature of the parison. The mandrel 
includes a flat plate with a major diameter, a flat portion and a notch 
opposed to the flat portion. The location means includes means for 
positioning the arm adjacent and contacting the cam and pivot means 
connected to the arm, wherein the arm pivots around the pivot means. 
Further features and advantages of the present invention will appear 
hereinbelow.

DETAILED DESCRIPTION 
Referring to the drawings, FIG. 1 shows in a block diagram the preferred 
cycle from injection station where the parisons or preforms are prepared, 
to receiving station where they are transferred to mandrels, preferably by 
a robot, to temperature conditioning station where the temperature is 
adjusted so as to be suitable for blowing and biaxial orientation (if 
desired), to the blowing station, and finally to the blown article removal 
station. The cycle is shown in U.S. Pat. No. 4,690,633, the disclosure of 
which is hereby incorporated by reference. The particular features of the 
overall cycle are not critical to the present invention. Thus, one can 
readily use an apparatus as shown and described in U.S. Pat. No. 
4,690,633. The parisons may or may not be prepared in-line with the other 
operations and may readily be made at a different time. The transfer path 
may take the form of an oval path, a straight path, or a horse-shoe shaped 
path, or any convenient configuration. 
The apparatus of the present invention is directed to aligning the parison, 
especially a non-symmetrical parison, with the blow mold and maintaining 
this alignment. With non-symmetrical parisons especially, after traversing 
a temperature conditioning station on a rotating mandrel, the parisons are 
not aligned properly, and the proper alignment must be achieved quickly, 
reliably, conveniently and repetitively so as not to impede the overall 
speed of the cycle. The present invention achieves this goal. 
FIG. 2 is a schematic view of the mandrel with parison thereon aligned and 
ready to be received by the blow mold. FIG. 2 shows a single mandrel 
carrying a single parison; however, it should be understood that the 
present invention may readily be used when the mandrel carries a plurality 
of parisons or when a plurality of mandrels carry a plurality of parisons. 
For convenience in the following discussion the present invention has been 
described with a single mandrel carrying a single parison. 
Referring to FIG. 2, pallets 10 are retained in channel track 11 having 
been transferred thereto from the conditioning station by means not shown. 
Pallets 10 hold rotatable mandrels 12 which in turn hold parisons or 
preforms 14 via projection 13, shown more clearly in FIGS. 4-7. As can be 
seen in FIG. 2 the parison is non-symmetrical since the present invention 
is most useful with this type of parison as it requires alignment after 
traversing a conditioning station on a rotating mandrel. 
Blowing station or finishing station 20 includes fixed platen 21 and 
movable platen 22 with blow mold half 23, and blow mold half 24 
therebetween in the shape of the bottle to be formed. Movable platen 22 
moves on tie rods 25 activated by motor 26. Base mold 27 is positioned 
above mold halves 23 and 24 to form the bottle bottom with piston 28 
connected thereto for moving the bottom mold into appropriate alignment 
for formation of the desired base for the bottle and motive means (not 
shown) connected thereto for activating said piston. Linkage means 29 are 
provided connected to the movable platen 22 and bottom mold 27 in order to 
maintain the desired positioning thereof. For clarity only the top linkage 
means are shown in FIG. 2. Channel track 30 sits spaced from but closely 
adjacent to channel track 11 so that pallets 10 can readily move into 
position in the blow mold. Pallets 10 may include depending leg 31 which 
may be engaged by a chain link (not shown) or any desired motive means for 
moving the pallet. As shown in FIG. 2, one mandrel-parison assembly is in 
position in the blow mold while a second is ready to be moved into the 
blow mold. FIG. 3 shows the mandrel-parison assembly in the blow mold. 
FIGS. 4-8 show the details of the alignment process in accordance with the 
present invention. Mandrels 12 are in the form of a flat plate rotatable 
about mandrel axis 33 and carrying a projection 13 thereon for holding the 
neck region of the parison. The shape of the neck region will determine 
the shape of the projection, e.g., in FIG. 4 the projection is circular. 
Naturally, the projection will rotate with the rotation of the mandrel so 
that the parison will rotate during its passage through the conditioning 
station. Naturally, any suitable means may be provided for rotating the 
mandrel, as for example, rotatable projection 32 (FIG. 3) integral with 
and depending from mandrel 12 which may be contacted by belts or chains 
(not shown) at the conditioning station causing rotation of the projection 
and mandrel. As can be clearly seen in FIG. 4, mandrel 12 is a flat plate 
and has a major diameter 41 with a flat portion 42 and a notch 43 opposite 
flat portion 42. Beneath the major diameter 41 the mandrel 12 carries 
eccentric cam 44 connected to the mandrel and depending therefrom. Mandrel 
12 mounted on pallet 10 as shown in FIG. 2 travels along centerline 45 
past movable arm 46. The movable arm pivots around post 47 and is mounted 
on the machine base. Arm 46 is moved into a first position by cylinder 
means 48. As pallet 100 carrying rotatable mandrel 12 advances out of the 
conditioning station, cam 44 contacts arm 46. The arm is not firmly held 
and therefore does not prevent passage of the pallet along the track. 
Instead, the cylinder means 48 acts like a spring and exerts pressure on 
the arm which in turn causes the cam and mandrel to rotate, if necessary, 
to present the least resistance to the passage of the cam and mandrel past 
the arm. FIGS. 5, 6 and 7 schematically show the moving mandrel and arm in 
three positions as the mandrel passes the arm. The arm 46 engages cam 44 
regardless of the cam's initial orientation with respect to the arm. Thus, 
mandrel 12, major diameter 41 and cam 44 are caused to rotate about axis 
33 by the pressure exerted on cam 44 by arm 46. As the pallet advances 
towards the blow station (to the right in FIGS. 6 and 7), arm 46 pivots 
around post 47 while maintaining pressure from cylinder 48 on cam 44. In 
the final position shown in FIG. 7, arm 46 bottoms on the cylinder stroke 
and is held so that arm face 49 is parallel to centerline 45 and mandrel 
face 42 ensuring that the pallet can pass the arm with cam 44 in such an 
orientation that notch 43 and flat 42 (on the major diameter 41) are 
oriented in a predetermined alignment. In addition, alignment block 51 is 
provided upstream of the blow mold as shown in FIGS. 5-7. The alignment 
block is in cooperating relationship with flat portion 42. Thus, as shown 
in FIG. 7 when flat portion 42 is aligned with the alignment block 51 the 
parison and mandrel are properly aligned and the mandrel is permitted to 
pass the alignment block. In the predetermined alignment dog 50 will 
engage notch 43 and remain engaged into the blow mold to insure retention 
of the alignment. Dog 50 may be driven by suitable motive means to engage 
notch 43 upstream of the blow mold as shown in FIG. 2, maintain the 
engagement to and in the finishing station and to release the engagement 
in the blow mold. The pallet with formed article is then transferred to a 
finished article removal station as shown in FIG. 1 for removal of the 
finished article and repeat of the cycle. 
Thus, in accordance with the present invention, the previously spinning 
mandrel is quickly and efficiently located and oriented for seating in the 
blow mold. This is accomplished without interruption during the passage of 
the mandrel along a track and the alignment is easily retained during the 
passage of the mandrel into the finishing station. 
It is to be understood that the invention is not limited to the 
illustrations described and shown herein, which are deemed to be merely 
illustrative of the best modes of carrying out the invention, and which 
are susceptible of modification of form, size, arrangement of parts and 
details of operation. The invention rather is intended to encompass all 
such modifications which are within its spirit and scope as defined by the 
claims.