JP5522709B2 - Cap manufacturing method - Google Patents

Description

The present invention relates to the production how the applied Ruki cap pollution preventing cover of an endoscope, for example.

Engaging Ruki cap to the present invention is used as a lens cap pollution preventing cover for an endoscope for example, pollution preventing cover of this kind is known, for example, in Patent Document 1. There, a pollution prevention cover is constituted by a cylindrical cover that covers the insertion portion of the endoscope and a lens cap provided at the tip of the cylindrical cover. The cylindrical cover is made of an elastic material such as silicon rubber, and the lens cap is made of a transparent plastic material.

  Regarding the lens cap, Patent Document 2 discloses that an acrylic resin or polycarbonate is used as a material for forming the lens cap, and that both front and back surfaces of the lens cap facing the lens portion of the endoscope are formed in a mirror shape with respect to the surface state. Further, there is disclosed a lens cap manufacturing method in which a female mold is formed of silicon rubber and a transparent plastic material is poured into the molding space to form a lens cap.

JP 2003-126011 (paragraph numbers 0013 and 0019, FIG. 2) Japanese Patent Laying-Open No. 2004-261408 (paragraph numbers 0013 and 0016, FIG. 8)

  According to the contamination prevention cover of Patent Document 2, both the front and back surfaces of the cap wall facing the lens portion of the endoscope in the lens cap can be formed in a mirror shape. However, since the lens cap is molded by a casting method using a female mold made of silicon rubber, there is a limit to reducing the wall thickness of the bottomed cylindrical lens cap, and further, the inside of the mirror-finished cap wall It is difficult to make the tissue homogeneous, and it is inevitable that the light image incident through the lens cap is distorted. In addition, the optical characteristics and dimensions of individual lens caps are likely to vary, and there are disadvantages that much time and cost are required for molding the lens caps.

  The inventor has studied to make the wall thickness of the lens cap thin and uniform by molding the lens cap by an injection molding method. This is because by reducing the wall thickness to the utmost limit, the distortion of the optical image accompanying the interposition of the lens cap is greatly reduced, and at the same time the optical characteristics of the individual lens caps are homogenized. However, the current molding method has a limit in reducing the wall thickness of the lens cap. For example, it is recommended that the wall thickness in the case of an integrally formed hinge is 0.15 mm or more. Although it may be possible to reduce the wall thickness to some extent beyond this recommended value, this type of champion data also has limitations.

  Naturally, the thin wall limit in the case of a lens cap having a bottomed cylindrical three-dimensional structure as a whole is expected to be larger than the previous champion data. This is because if the wall thickness is small, the molding space is too narrow, and the molten resin injected into the molding space solidifies almost simultaneously with the contact with the mold, so that the molten resin cannot be poured into the entire molding space. In order to cope with such a situation, the mold was heated and the injection pressure was further increased to attempt molding. However, most of the obtained molded products had molding defects (short shot). It was also found that even if the lens cap could be molded, it was difficult to accurately release the lens cap having a thin wall thickness from the mold.

The present invention, which was proposed in the Patent of the background, a general purpose of the caps, such as a lens cap wall thickness is sufficiently thin film shape can be reliably mass-produced, the manufacturing method of the caps It is to provide .

Manufacturing method of engaging Ruki cap to the present invention comprises the steps of injection molding a dummy male 15 having a boss 20 which matches the inner shape of the bottomed cylindrical caps 11, the dummy male 15 obtained a process of clamping by loading the caps 11 in the interior of the mold for molding, shaping the cap front body 16 by injecting molten resin into the molding space S between the dummy male 15 and the molding die characterized in that it comprises a molding process of the cap front body 16 and a cutting process to obtain the caps 11 by cutting a predetermined position of the obtained cap front body 16.

In the above production method, the cap front body 16 after the molding process, the cap front body 16 and the dummy male 15 from the molding die includes a process to obtain a composite molded article 17 with a release simultaneously, in the cutting process You can obtain caps 11 performs cutting for a given point of the composite molded article 17 including dummy male 15.

In the method of manufacturing the caps of the present invention, the dummy male 15 loaded inside of the mold for molding the caps 11, injecting molten resin into the molding space S between the dummy male 15 and the molding die cap the front body 16 by molding, by cutting a predetermined position of the obtained cap front body 16 so as to obtain caps 11 and. Thus, when injection molding is performed with the dummy male mold 15 loaded in the molding die, the thermal conductivity of the dummy male mold 15 is sufficiently smaller than that of the molding die, so that the molding space S is filled. It is possible to prevent the molten resin from being rapidly cooled and solidified. Therefore, according to the manufacturing method of the caps of the present invention, it can be reliably filled with the molten resin very narrow molding space S, and reliably mass-produced caps 11 having a thin-walled peripheral wall 13 and the end wall 14 , Can reduce its cost.

In the above manufacturing method, after molding the cap front body 16 and so as to obtain a composite molded article 17 simultaneously release the cap front body 16 and the dummy male 15 from the molding die, the caps 11 parts The mold can be accurately released from the mold without damaging the mold. In the case of releasing independently only cap front body 16, there is a risk that damaged portions of the caps 11, it is necessary to carefully release while applying labor. Moreover, when to obtain the caps 11 by cutting a predetermined position of the mold from the release composite molded article 17, it is possible to cut the state can cap 11 which is supported firmly in the boss 20, the caps 11 Cutting can be performed accurately and conveniently. Further, after the portion to be the caps 11 by cutting each boss 20, by removing from the boss 20, which is cut caps 11, it can be accurately separated without damaging the caps 11.

Shows (Embodiment) FIGS. 1 to 10 and the pollution preventing cover for an endoscope showing an application example of the engagement Ruki cap to the present invention, an embodiment of a method for manufacturing caps. 2, pollution preventing cover is provided with a tubular cover 10 that covers the insertion portion 1 of the endoscope, a lens cap (caps) 11 fixed to the distal end of the cover 10, the proximal end of the cover 10 The mounting structure 12 is used. A lens portion 2 is provided at the distal end of the insertion portion 1, and an illumination window 3 and an observation window 4 are arranged inside the protruding end of the lens portion 2. The outer surfaces of the illumination window 3 and the observation window 4 are covered with a lens cap 11. The mounting structure 12 is fixed to the operation unit of the endoscope and maintains the mounting state of the pollution prevention cover.

  The cover 10 is made of a cylinder that is extruded from polypropylene and has a wall thickness of 0.5 mm. As shown in FIG. 10, the lens cap 11 is formed of a bottomed cylindrical injection-molded product integrally provided with a round cylindrical peripheral wall 13 and an end wall 14 that closes one end of the peripheral wall 13. The lens cap 11 is molded from transparent polypropylene, and is integrally welded to the outer surface of the tip of the cover 10 as shown in FIG. The heat-welded portion is formed in an endless shape so as to circulate around the peripheral wall 13 of the lens cap 11, whereby the joint portion between the lens cap 11 and the cover 10 can be sealed.

  As shown in FIG. 10, the lens cap 11 has a diameter of slightly less than 3 mm and a height of 2 mm, and the thickness dimension of the peripheral wall 13 and the end wall 14 is 0.05 to 0.08 mm. The draft of the surrounding wall 13 is 3 degrees. In the lens cap 11 in each figure, the thickness of the peripheral wall 13 and the end wall 14 is exaggerated from the actual thickness.

  As described above, the lens cap 11 in which the peripheral wall 13 and the end wall 14 are formed thin is injection-molded by the following method. As described above, if the wall thickness of the peripheral wall 13 and the end wall 14 is small, the molten resin injected into the molding space is solidified almost at the same time as it contacts the mold. The resin cannot be injected. This means that the molten resin injected is forcibly cooled by a mold having a high thermal conductivity. In the present invention, the molten resin is prevented from being cooled by the mold. By doing so, the thin lens cap 11 can be formed accurately.

  Specifically, as shown in FIG. 1, a dummy male mold 15 that prevents heat conduction to the mold is loaded inside the molding mold for the lens cap 11, and the dummy male mold 15, the molding mold, The molten resin was injected into the molding space S between them to mold the cap pre-stage body 16, and the lens cap 11 was obtained from the cap pre-stage body 16. That is, by providing the dummy male mold 15, the molten resin is prevented from being cooled by the mold, and the molten resin can be reliably injected and filled into the extremely narrow molding space S.

  In FIG. 4, the dummy male mold 15 protrudes from a round cylindrical boss 20 that matches the inner surface shape of the lens cap 11, a flange 21 that projects around the lower surface opening of the boss 20, and an opposing peripheral surface of the flange 21. It consists of an injection-molded product that is integrally provided with a pair of positioning projections 22 and is made of polycarbonate. The height of the boss 20 is set larger than the height dimension of the lens cap 11, and the diameter dimension of the flange 21 is set to 5 mm. The dummy male mold 15 is formed of polycarbonate because it is not compatible with polypropylene, which is the material for forming the lens cap 11, and the melting temperature of the polycarbonate is higher than the melting temperature of the polypropylene, so that the lens cap 11 is molded. This is to prevent the dummy male mold 15 from melting.

  As shown in FIG. 5, the molding die for the lens cap 11 includes a fixed die 25 and a movable die 26, and loading for loading the dummy male die 15 on the movable die 26 side. A recess 27 is formed. The fixed mold 25 and the movable mold 26 are provided with a molding space S for molding the outer shape of the lens cap 11, left and right runner spaces 28 for guiding the molten resin to flow, and both the runner spaces 28 and the former molding space. A pair of gate spaces 29 that bridge S are formed.

  Usually, the movable mold 26 is guided and fixed to the fixed mold 25 by being guided by guide pins provided on the fixed mold 25. However, the movable mold 26 for molding the lens cap 11 having a sufficiently small wall thickness as described above needs to be positioned with higher accuracy, and sufficient positioning accuracy cannot be obtained with a conventional guide pin. Therefore, as shown in FIG. 5, a tapered positioning surface 31 is provided on the joint surface between the movable mold 26 and the fixed mold 25, so that the movable mold 26 in the mold-clamped state is accurately set with respect to the fixed mold 25. It can be positioned. Reference numeral 32 denotes a spool space, and reference numeral 33 denotes a knockout pin for the dummy male die 15. Although not shown, knockout pins are also arranged at a plurality of locations facing the runner space 28.

  The lens cap 11 is formed through the molding processes shown in FIGS. 5, 1, 6, and 7 in order. First, as described above, the dummy male mold 15 including the boss 20 that matches the inner surface shape of the bottomed cylindrical lens cap 11 is injection-molded. Next, as shown in FIG. 5, with the molding die opened, the dummy male die 15 is loaded into the loading recess 27 of the movable die 26 and clamped. At this time, the movable mold 26 is accurately positioned with respect to the fixed mold 25 by the tapered positioning surface 31. The state is shown in FIG. 1, and the dummy male mold 15 and the surrounding wall of the molding space S are opposed to each other with a uniform gap therebetween.

  Next, molten resin is injected into the molding space S through the runner space 28 and the gate space 29 to mold the cap front body 16 as shown in FIG. As the polypropylene to be injected here, a commercially available high-flow type transparent polypropylene having excellent fluidity is used. The injected molten resin contacts the boss 20 of the dummy male mold 15, but the thermal conductivity of the dummy male mold 15 is sufficiently smaller than that of the mold. Therefore, it is possible to prevent the molten resin from being rapidly cooled, and it is possible to reliably fill the molten resin in the extremely narrow molding space S before the injected molten resin is solidified.

  The cap pre-stage body 16 is an integrated product of resin filling the runner space 28, the gate space 29, and the molding space S, and is released from the molding die together with the dummy male mold 15. Specifically, by separating the movable mold 26 from the fixed mold 25, the cap front stage body 16 is released from the fixed mold 25 together with the movable mold 26. Furthermore, as shown in FIG. 7, the dummy male mold 15 and the cap front body 16 can be separated from the movable mold 26 by pushing them out with the knockout pin 33 and a knockout pin (not shown). At this time, since the portion that becomes the lens cap 11 is held by the boss 20 of the dummy male die 15, excessive force does not act on the portion that becomes the lens cap 11 when releasing with the knockout pin 33. Therefore, the shape and structure of the portion that becomes the thin lens cap 11 can be maintained in an appropriate state.

  As shown in FIG. 8, the composite molded product 17 taken out from the molding die is an integrated product of the dummy male mold 15 and the cap front body 16. The lens cap 11 is obtained by cutting a predetermined portion of the composite molded product 17. Specifically, a portion to be the lens cap 11 of the cap front body 16 is cut along with the boss 20 of the dummy male die 15 according to the cutting line 35 shown in FIG. 9, and the cut boss 20 is separated to open one end. The bottomed cylindrical lens cap 11 can be obtained.

  As described above, after cutting the portion that becomes the lens cap 11 together with the boss 20 and then removing the lens cap 11 from the cut boss 20, the lens cap 11 can be accurately separated without being damaged. Further, since the lens cap 11 can be cut with the boss 20 firmly supported, the lens cap 11 can be cut accurately and simply. Although the lens cap 11 can be cut after extracting the dummy male mold 15 from the cap front body 16, in that case, it is necessary to support the cutting portion in order to cut accurately.

  Incidentally, the diameter of the completed lens cap 11 is less than 3 mm, and the height is only 2 mm. Moreover, the wall thickness of the peripheral wall 13 and the end wall 14 is only 8/100 mm or less. Therefore, when the lens cap 11 is handled in a completed state, the lens cap 11 may be inadvertently crushed or partly deformed. In some cases, the lens cap 11 may be lost. In order to prevent such deformation and loss, the lens cap 11 is preferably separated from the composite molded product 17 immediately before being joined to the cover 10. Until the lens cap 11 is cut, it is handled in the state of the composite molded product 17 or is transported in the state of the composite molded product 17 when transport is necessary.

  If necessary, the runner portion formed in the runner space 28 is cut and removed by the gate portion formed in the gate space 29, so that the composite consisting of the portion that becomes the lens cap 11 and the dummy male die 15 is integrated. The body can be transported or handled in the state of the previous complex. Further, if necessary, the lens cap 11 can be handled or transported after the portion that becomes the lens cap 11 is cut together with the boss 20 and then held in the boss 20. In either case, it is possible to reliably prevent inadvertent deformation and loss of the lens cap 11.

Figure 11 shows another embodiment of a lens cap (caps) 11 according to the present invention. The endoscope in this embodiment is a side-view type endoscope in which an illumination window 3 and an observation window 4 are arranged inside one peripheral surface of the lens unit 2. The lens cap 11 includes a peripheral wall 13 that covers the outer surfaces of the illumination window 3 and the observation window 4, and an end wall 14. In the lens cap 11 in this embodiment, it is necessary to set the height dimension of the peripheral wall 13 larger than that of the lens cap 11 described in the previous embodiment. It is necessary to make it larger than the wall thickness of the peripheral wall 13 described in the example. Since others are the same as the previous embodiment, the same reference numerals are assigned to the same members, and descriptions thereof are omitted.

  In addition to the above embodiments, the dummy male mold 15 can be formed of a plastic material other than polycarbonate, such as polysulfone, polyarylate, polyetherimide, polyphenylene sulfide, and the like. Similarly, the lens cap 11 and the cover 10 can be formed of a material having a melting temperature lower than that of the dummy male mold 15 such as a plastic material other than polypropylene, such as polyethylene, thermoplastic elastomer, or acrylic. The dummy male mold 15 only needs to include at least the boss 20.

  The lens cap 11 can be changed to various shapes according to the outer shape of the lens unit 2. For example, the end wall 14 does not need to be flat and can be formed of a partial spherical surface rounded into a semicircle. The end wall 14 can be formed as a flat surface that is inclined obliquely with respect to the center of the cylinder axis of the peripheral wall 13. Furthermore, the peripheral wall 13 does not need to be a round cylinder, and can be formed in a cross-sectional polygonal shape or a cross-sectional shape that matches the cross-sectional shape of the lens unit 2.

Engagement Ruki cap 11 in the present invention, in addition to the lens cap to be applied in a pollution cover of the endoscope, the distal end cover of the machine tool of the spot illuminator, such as a lens cap monitor camera for monitoring the production process, regular It can be used as a cover or cap for optical equipment used in a contaminated environment that needs to be cleaned. Also, covers and caps for equipment used in a closed environment, such as lens covers for microscopes that observe infectious organisms, tip covers for spot illuminators used with microscopes, caps for injection needles for analysis, etc. Can be used as

It is sectional drawing of the shaping die for lens caps. It is a front view which shows schematic structure of the pollution prevention cover for endoscopes. It is sectional drawing which shows the mounting state of a pollution prevention cover and a lens cap. It is a perspective view of a dummy male type. It is sectional drawing of the state which open | released the shaping | molding die for lens caps. It is sectional drawing of the shaping die which shows the state which shape | molded the dummy front stage body. It is sectional drawing of the shaping die which shows the mold release state of a composite molded product. It is a perspective view of a composite molded product. It is a partially broken front view of a composite molded product. It is sectional drawing of a lens cap. It is sectional drawing which shows another Example of a lens cap.

Explanation of symbols

Lens portion 10 cover 11 lens cap of the insertion portion 2 endoscope 1 endoscope (caps)
13 Peripheral wall 14 End wall 15 Dummy male mold 16 Cap front body 17 Composite molded product 20 Boss S Molding space

Claims (2)

Bottomed cylindrical caps (11) dummy male having a boss (20) which matches the inner shape of the (15) comprising the steps of injection molding,
A process resulting dummy male (15) were loaded in the interior of the mold for molding the caps (11) to clamping,
A molding process of the cap front body (16) for injecting molten resin into the molding space (S) between the dummy male mold (15) and the molding die to mold the cap front body (16) ;
Features and to Ruki cap manufacturing method that comprises a cutting process to obtain by cutting a predetermined position caps (11) of the resulting cap front body (16). After the molding process of the cap front body (16) includes a process of obtaining a cap front body from the molding die (16) and the dummy male (15) to simultaneously release to a composite molded article (17),
Wherein in the cutting process, perform cutting with respect to a predetermined position of the composite molded article comprising a dummy male (15) (17) to obtain the caps (11), the manufacture of caps according to claim 1 Way .

Images