FIELD OF THE INVENTION

This invention relates to an apparatus for feed¬ ing hypodermic needles into corresponding recesses of the mold cavity of a molding machine in which the needles are to be encased individually in plastic sheaths which will physically protect the needle tips and keep them steri¬ lized until ready for use. BACKGROUND OF THE INVENTION Prior to the present invention, it has been a known practice to drop the needles by gravity from a maga¬ zine into corresponding recesses of the mold cavity just before the plastic is introduced to encase the needles. Experience has shown that many such needles become damaged by the gravity feeding operation, acquiring burrs or other surface irregularities on the tip which make the needle unsuitable .for use.

The present invention is directed to a novel feeding mechanism for use with a molding machine of this general type to feed the hypodermic needles into cor¬ responding recesses of the mold cavity just before a mold¬ ing operation but without damaging the needle tips. SUMMARY OF THE INVENTION

A principal object of this invention is to pro- vide such a feeding mechanism which feeds the needles into corresponding recesses of the mold cavity from an

overlying magazine in two steps: first, from the magazine down into corresponding openings in a shuttle plate which at that time are blocked from the mold cavity recesses; and afterwards, from the shuttle plate down into the mold cavity recesses after the shuttle plate openings are brought into communication with the mold cavity recesses.

Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment, which is illustrated - in the accompanying drawings. DESCRIPTION OF THE DRAWINGS

Figure 1 is a front elevation of a molding machine equipped with two needle feeding apparatuses in accord¬ ance with the present invention; Figure 2 is a top plan view of the machine shown in Figure 1;

Figure 3 is a view similar to Figure 2 but with the bQttom mold plate of the machine displaced to the right to receive hypodermic needles from the feeding ech- anism there and with parts broken away to reveal part of the mold cavity in this mold plate;

Figure 4 is a fragmentary vertical section taken along the line 4—4 in Figure 3 longitudinally through the needle feeding mechanism in the loading posi- : tion of the latter;

Figure 5 is a view similar to Figure 4 but show¬ ing the needle feeding mechanism in its loaded position;

Figure 6 is a fragmentary vertical cross-section taken along the line 6—6 in Figure 5; Figure 7 is a perspective view of the needle feeding mechanism with parts broken away for clarity;

Figure 8 is a horizontal longitudinal section through the needle feeding mechanism taken along the line 8—8 in Figure 1; Figure 9 is a top plan view of the molded pro¬ duct produced by the molding machine of Figure 1 and com¬ prising several hypodermic needles individually encased

in plastic;

Figure 10 is a perspective view of one of the sixteen sheathed hypodermic needle units in the Figure 9 product; and Figure 11 is an exploded perspective view of this needle unit after the removal of the plastic head from the tip of the needle.

Before explaining the disclosed embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embo iments. Also, the terminology used herein is for the purpose of de¬ scription and not of limitation. DETAILED DESCRIPTION

The machine shown in Figures 1-8 is to produce a molded product as shown in plan view in Figure 9. This product has sixteen identical hypodermic needle units N arranged in two rows of eight each. Referring to Figures 10 and 11, each hypodermic needle unit N has a molded plastic casing 15 of generally cross-shaped cross-section in which a hypodermic needle

16 is embedded, extending lengthwise centrally in the casing. The tip of the needle is encased in a plastic head 17 of generally triangular configuration which is molded integral with the casing 15. The narrowest part of the plastic head 17 is joined to the plastic casing 15 at one end and may be broken away from it by twisitng when it is desired to expose the tip of needle 16 for use, as shown in Figure 11.

As shown in Figure 9, the wide end of the head

17 of each hypodermic needle unit N is molded integral with a short plastic stem 18 which is of reduced cross- section at its juncture with the head 17 so that it is easy to detach the head and the rest of the hypodermic needle unit from the rest of the integral molded product shown in Figure 9. The opposite end of each stem 18 is

joined to a cross piece 19 which, in turn, is joined to a central longitudinal piece 20.

It is to be understood that the central piece 20, the two cross pieces 19, the sixteen stems 18, the sixteen heads 17 and the sixteen casings 15 are all formed as a single, integral molded body or structure of suitable plastic material.

The present invention is directed to a novel apparatus for feeding the hypodermic needles 16 into corresponding recesses of the mold cavity just before the plastic is introduced to form the individual casings 15 and heads 17 embedding these needles, as well as the connecting stems 18, caross pieces 19 and central piece 20 of the integral product shown in Figure 9.

Referring to Figure 1, in broad outline the molding machine which embodies the present invention comprises a mold hav- ing a bottom plate 21 with an upwardly facing mold cavity open at the top of this plate and a vertically reciprocable platen 22 which can move down to close the mold cavity when the product of Figure 9 is to be molded, a needle feed mechanism 23 according to the present invention on the left side of the platen 22, and a similar needle feed mechanism 24 on the right side. The bottom plate 21 of the mold is moved cyclically from beneath the platen 22 to the left beneath the needle feed inechanism 23 and to the right beneath the needle feed mechanism 24, in either case to re¬ ceive the hypodermic needles frc the feed mechanism just before the next molding operation takes place, at which time the bottom mold plate 21 will be back beneath the reciprocable platen 22.

As shown in Figure 2, the laterally shiftable bottom plate 21 of the mold has a generally flat top face with a recess or cavity C whose shape corresponds to that of the molded product shown in enlarged detail in Figure 9. The mold cavity presents sixteen recesses for receiving the sixteen hypodermic needles individually.

Figure 5 shows the bottom mold plate 21 shifted to the right beneath the needle feeding mechanism 24 on

that side, with a needle 16 having been inserted in each corresponding recess of the mold cavity C. As shown in Figure 6, at this time each needle 16 rests on two inserts 25 and 26 projecting up from the bottom of the mold cavity

5 C so that plastic introduced into the mold cavity through injection passageways will completely surround the needle except at these inserts. As shown in Figure 11, the molded plastic casing 15 has grooves 25a and 26a where the needle 16 is exposed. These grooves are formed where the inserts

10. 25 and 26 in the corresponding recess of the mold cavity engaged the needle.

Referring to Figε^ 7 and 8, the needle feeding mechanism 24 on the right side of the machine comprises a rigid frame having a generally flat, rectangular inner

15 piece 27 bolted to the housing 28 of the molding machine, a flat rectangular back piece 29 bolted to the inner piece 27 and extending perpendicularly from it to the

_ right (i.e., away from the platen 22), and a flat rec¬ tangular-outer piece 30 joined integrally to the back

20 piece 29 at its outer end and extending forward from the back piece parallel to the inner piece 27. The inner piece 27, back piece 29 and outer piece 30 form a three- sided, rigid frame which is open at the front. Near the open front of this frame a front guide rod 31 extends

25 horizontally between the inner and outer pieces 27 and 30 of the frame. A similar horizontal rear guicfe rod 32 extends between the frame pieces 27 and 30 a short dis¬ tance in front of the back piece 29 of the frame. The guide rods 31 and 32 extend parallel to each other at the

30 same level.

A magazine for holding needles 16 is mounted in the frame 27, 29, 30, 31 and 32. This magazine is slid- able back and forth between the frame pieces 27 and 30 through 1/4 inch strokes. The magazine has rectangular

35 front and back plates 33 and 34, both extending parallel to the back piece 29 of the frame. The magazine also has a flat, rectangular divider plate 35 extending parallel

to its front and back plates 33 and 34 and located midway between them, spacers 36 and 37 engaged between its front plate 33 and divider plate 35 at their opposite ends, and spacers 38 and 39 engaged between divider plate 35 and its rear plate 34 at their opposite ends. These parts of the magazine -areheld rigidly assembled by bolts and nuts.

A front guide block 40 is bolted to the front plate 33 of the magazine and is slidably mounted on the front guide rod 31 of the frame. Similarly, a rear guide Q block 41 on the back of the magazine is slidably mounted on the rear guide rod 32 of the frame.

As shown in Figure 4, the spacers 36 and 37 at opposite ends of the magazine toward the front have op¬ positely inclined faces 36a and 37a, respectively, on the 5 inside, which taper slightly toward each other downward along these faces. The front plate 33 of the magazine has a flat, vertical, rear face. The divider plate 35 has a flat, vertica'l front face. These faces of the magazine de-fine a front hopper 42 which is of uniform depth from 0 .front to back and is of progressively decreasing side-to- side width from top to bottom. Needles 16 are piled in this front hopper extending longitudinally horizontally from the front plate 33 to the divider plate 35.

The magazine has a similar rear hopper 43 behind 5 the divider plate 35. At the ends of this hopper the spacers 38 and 39 present respective downwardly and inward¬ ly inclined flat inside faces 38a and 39a (Figure 2) . This rear hopper holds a large number of needles 16, each positioned horizontally and extending lengthwise from the 0 back face of divider plate 35 to the inside front face of rear plate 34.

The magazine has an upper bottom plate 44 (Fig¬ ures 4 and 5) and a lower bottom plate 45, both attached to the front and rear plates 33 and 34 at the bottom. 5 There is a small vertical clearance between plates 44 and 45. A flat rectangular shuttle plate 46 is received in this clearance and it slidably engages the upper bottom

plate 44 from below and the lower bottom plate 45 from above. The shuttle plate 46 extends beyond plates 44 and 45 at both ends of the magazine. An end piece assembly 47 is bolted to the shuttle plate 46 at one end, and a similar end piece assembly 48 is bolted to the shuttle plate at its opposite end. These end piece assemblies snugly engage the inside faces of frame pieces 27 and 30, so that the shuttle plate is substantially fixidly posi¬ tioned inside the frame. The width of the magazine from side to side is 1/4 inch shorter than the distance be¬ tween the respective inside faces 47a and 48a of the end piece assemblies 47 and 48 on the shuttle plate.

At the bottom of the front hopper 42 the upper bottom wall 44 of the magazine presents eight openings 49 (Figure 8) spaced apart from left to right and each elongated from front to back. Each opening 49 is slightly longer than a single nee le 16. As shown in Figures 4 and 5, along its entire length from front to back on the maga¬ zine each opening 49 is of tapered cross-section, being widest at the top and narrowest at the bottom. The width at the top is slightly less than the thickness of two needles 16 and at the bottom is slightly more than the thickness of a single needle. The needles pass down by gravity one at a time through the openings 49. As shown in Figure 8, the upper bottom wall 44 of the magazine presents a similar second series of open¬ ings 50 at the bottom of the rear hopper 43.

The shuttle plate 46 presents eight elongated openings 51, shown in phantom in Figure 8, which are adapted to be aligned individually with the openings 49 in the upper bottom wall 44 at the bottom of the front hopper 42. Also, the shuttle plate has a second series of eight elongated openings, shown in phantom at 52 in Figure 8, which are aligned individually with the openings so in the upper bottom wall 44 at the bottom of the rear hopper 43 when the openings 51 and 49 are aligned. Figure 4 shows the shuttle plate openings 51 registering with the

upper bottom wall openings 49. The width of each shuttle plate opening 51 or 52 is just slightly greater than the width of a single needle 16, so that when the openings 51 and 49 are aligned and the openings 52 and 50 are ^: aligned a single needle 16 drops down into each shuttle plate opening 51 or 52.

The lower bottom plate 45 on the magazine pre¬ sents a. series of eight elongated openings 53 at the bottom- of the front hopper 42, and a second series of - eight- similar openings at the bottom of the rear hopper 43. Each of these openings in the lower bottom plate 45 is wider at the top than at the bottom. Each opening in the bottom plate 45 directly overlies and registers with a corresponding recess of the mold cavity C in the bottom mold plate 21 when the latter is beneath the right- hand magazine 24. Each of the lower bottom plate open¬ ings 53 is offset laterally (from left to right in Fig. 4) 1/4 inch from the corresponding opening 49 in the upper bottom plate 44. With this arrangement each needle 16 passes down through an opening 49 or 50 in the upper bottom plate 51 into a corresponding opening 51 or 52 in shuttle plate 46 when the shuttle plate openings register with the openings in the upper bottom plate 44, as shown in Figure - 4. in this position of the parts, the shuttle plate open¬ ings? are offset laterally from, and out of registration with, the openings 53 in the lower bottom plate 45 on the magazine. Later, when the shuttle plate openings register with the openings 53 in the lower bottom plate 45, each needle passes from the shuttle plate opening down through the registering opening 53 in the lower bottom plate 45 and into the corresponding recess of the mold cavity C in the bottom plate 21 of the mold, as shown in Figure 5.

Before the lower mold plate 21 moves over beneath ^' the needle feeding mechanism 24 on the right (i.e., in the position shown in Figure 1) , the magazine and the shuttle plate- 46 are positioned with respect to each other as shown

- _. - in Figures 5 and 8, that is, with the shuttle plate openings 51 and 52 out of registration with the openings 49 and 50 in the upper bottom plate 44 on the magazine, and with the shuttle plate openings in registration with the openings 53 in the lower bottom plate 45.

When the mold plate 21 moves to the right to a position beneath the needle feeding mechanism 24, the magazine is displaced 1/4 inch to the right, to the posi¬ tion shown in Figure 4, so that a single needle drops from each opening 49 or 50 in the upper bottom plate 44 on the magazine into the corresponding shuttle plate open¬ ing 51 or 52, which now registers with it.

Then, when the mold plate 21 starts to move back to the left toward the molding position beneath the vertically reciprocable platen 22, the magazine is dis¬ placed back to the left to the position shown in Figure 5, bringing each opening 53 in its lower bottom plate 45 into registration with a corresponding shuttle plate open¬ ing. Consequently, a single needle drops from each shut- tie plate opening down through the corresponding opening 53 in the lower bottom plate 45 and into the recess of the mold cavity C which is directly below.

Preferably, the person operating the molding machine positions the magazine by grasping it manually and sliding it along the guide rods 31 and 32 between the just-described positions with respect to the mold plate 21 after the mold plate has moved beneath that magazine. The machine operator may do this conveniently by grasp¬ ing the guide block 40 on the front of the magazine. Except for the needle feeding apparatus in ac¬ cordance with the present invention, located on each side, the molding machine itself may be a plastic injection molding machine known as "Newbury Eldorado Model V4-30ARS," sold by Newbury Industries, Inc., Newbury, Ohio 44065. The needle feeding apparatus 23 at the left side of the molding machine in Figure 1 is a mirror image of the feeding apparatus 24 on the right side and need not

be described in detail. Preferably, the bottom mold plate 21 is shifted alternately to the left and right, so that every other needle feeding operation takes place successively from the left and right feeding apparatuses 23 and 24, respectively.