VALVE PIN PLATE

FIELD

[0001] The present application relates to a valve-gating injection molding apparatus, and in particular to a valve-gating injection molding apparatus having a valve pin plate to which a valve pin is releasably coupled.

BACKGROUND

[0002] Valve-gating hot runner systems may employ a valve pin plate to which a plurality of valve pins are coupled. Each valve pin is for regulating the flow of molding material to a respective mold cavity. The valve pin plate is coupled to an actuator which translates the valve pin plate and valve pins coupled thereto between a closed position in which molding material is prevented from entering a mold cavity and an open position in which molding material is able to enter a mold cavity.

BRIEF SUMMARY

[0003] An aspect of the present application provides an injection molding apparatus comprising: a hot runner system including a manifold having a manifold channel extending between a manifold inlet and a manifold outlet, a nozzle having a nozzle channel extending therethrough, the nozzle channel in fluid communication with the manifold channel via the manifold outlet; a valve pin extending through the nozzle towards a mold gate, a valve plate assembly including a valve pin plate coupled to an actuator which, in operation, axially moves the valve pin plate between at least two positions and a valve pin holder coupling the valve pin to the valve pin plate, the valve pin holder including a lateral bore laterally extending into the valve pin holder from an outer surface of the valve pin holder, and a coupling shaft received in the lateral bore, wherein the coupling shaft is selectively axially positionable within the lateral bore between an engaged position in which the valve pin is physically coupled to the valve pin plate by the coupling pin shaft and a disengaged position in which the valve pin is physically decoupled from the valve pin plate; and a plurality of mold plates defining an enclosure in which the valve plate assembly is received, wherein one of the plurality of mold plates includes a mold plate access passage extending from a peripheral side of the one of the plurality of mold plates to the enclosure, the mold plate access passage having a sightline view of a proximal end of the coupling shaft when the valve pin plate is in an aligned position.

[0004] The injection molding apparatus can further comprising an another valve pin and the valve plate assembly further includes an another valve pin holder coupling the another valve pin to the valve pin plate, the another valve pin holder including an another lateral bore laterally extending into the another valve pin holder from an outer surface of the another valve pin holder, and an another coupling shaft received in the another lateral bore, the another coupling shaft includes a coupling shaft access passage extending axially through the another coupling shaft, such that the mold plate access passage has a sightline view through the coupling shaft access passage to the proximal end of the coupling shaft when the valve pin plate is in the aligned position.

[0005] The valve pin holder can include a socket and a plug, the socket defines a socket bore in which the plug is reciprocably received.

[0006] The valve pin can be coupled to the plug; and in the disengaged position, the valve pin is decoupled from the socket.

[0007] The another valve pin holder can include an another socket and an another plug, the another socket defines an another socket bore in which the another plug is reciprocably received.

[0008] The another valve pin can be coupled to the another plug; and in the disengaged position, the another valve pin is decoupled from the another socket.

[0009] The lateral bore can include a socket bore and a plug bore, the socket bore includes a proximal end and a distal end diametrically opposite the proximal end, the coupling shaft includes a head and an alignment portion distal from the head, the coupling shaft threadably connected with a portion of the plug bore, the head includes a screw-drive to receive a tool for rotating the coupling shaft to linearly displace the coupling shaft within the lateral bore, when the valve pin holder is in the engaged position, the alignment portion is received in the distal end of the socket bore.

[0010] The another lateral bore can include an another socket bore and an another plug bore, the another socket bore includes a proximal end and a distal end diametrically opposite the proximal end of the another socket bore, the another coupling shaft includes a head and an alignment portion distal from the head of the another coupling shaft, the another coupling shaft threadably connected with a portion of the another plug bore, the head of the another coupling shaft includes a screwdrive to receive a tool for rotating the another coupling shaft to linearly displace the another coupling shaft within the another lateral bore, and when the valve pin holder is in the engaged position, the alignment portion of the another coupling shaft is received in the distal end of the another socket bore.

[0011] The coupling shaft access passage can be dimensioned to allow a tool to pass through to engage the screw-drive of the coupling shaft.

[0012] The valve pin holder can include a disengagement limiter to limit an axial retraction distance of the coupling shaft from the lateral bore.

[0013] The disengagement limiter can be a circlip received in a circumferential groove in the plug bore.

[0014] The socket can define a plurality of socket bores, each of the plurality of socket bores can be axially aligned with the coupling shaft.

[0015] The socket can define a plurality of locating slots, the plug includes a locating shaft receivable in one of the plurality of locating slots to orient an angular position of the plug relative the socket about an axis of the valve pin holder.

[0016] The another socket can define a plurality of another socket bores, each of the plurality of another socket bores can be axially aligned with the another coupling shaft.

[0017] The another socket can define a plurality of another locating slots, the another plug includes an another locating shaft receivable in one of the another plurality of another locating slots to orient an angular position of the another plug relative the another socket about an axis of the another valve pin holder.

[0018] The socket can axially overlap the plug by an amount greater than an axial translation distance of the valve pin plate as the valve pin plate moves between a closed position in which molding material is prevented from entering a mold cavity and an open position in which molding material is able to enter a mold cavity.

[0019] The valve pin holder can include a disengagement indicator to provide tactile feedback to indicate whether the valve pin holder is in the engaged position or disengaged position.

[0020] The disengagement indicator can be an O-ring received in an inner circumferential groove in a proximal plug bore portion of the plug bore and an outer circumferential groove in the head of coupling shaft.

[0021] The mold plate access passage can be upstream of the valve pin plate.

[0022] The mold plate access passage can be downstream of the valve pin plate.

[0023] The valve pin can be coupled to the socket; in the disengaged position, the valve pin is decoupled from the plug.

[0024] The valve pin holder can include a plug, the valve pin is coupled to the plug, the valve pin plate includes a valve plate access passage; in the engaged position, the coupling shaft is received in the plug and the valve plate access passage.

BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings are not to scale.

[0026] FIG. 1 is a sectional view of an injection molding apparatus in accordance with an embodiment of the present application.

[0027] FIG. 2 is an enlarged view of a portion P of FIG. 1 showing a valve pin holder in accordance with an embodiment of the present application and another valve pin holder in accordance with another embodiment of the present application.

[0028] FIG. 3 is an enlarged view of the portion P of FIG. 1 showing a valve plate assembly of the injection molding system in an open position. [0029] FIG. 4 is an enlarged view of the portion P of FIG. 1 showing the valve plate assembly in the open position and a valve pin holder of the injection molding apparatus in a disengaged configuration

[0030] FIG. 5 is an enlarged view of the portion P of FIG. 1 showing the valve plate assembly in the open position and another valve pin holder of the injection molding apparatus in the disengaged configuration.

[0031] FIG. 6 is a perspective view of a valve pin holder installable in an injection molding apparatus in accordance with yet another embodiment of the present application.

[0032] FIG. 7 is a sectional view of the valve pin holder of FIG. 6 taken along line 7-7, shown installed in a schematic injection molding apparatus having a valve pin plate in an aligned position, and the valve pin holder is in an engaged configuration.

[0033] FIG. 8 is a sectional view of FIG.7 having the valve pin plate is in the open position and the valve pin holder is in the disengaged configuration.

[0034] FIG. 9 is a sectional view of the valve pin holder of FIG. 6 taken along line 9-9, shown installed in the schematic injection molding apparatus with the valve pin plate in the aligned position and the valve pin holder in the engaged configuration.

[0035] FIG. 10 is a sectional view of the valve pin holder of FIG. 6 taken along line 10-10, shown installed in the schematic injection molding apparatus with the valve pin holder in the engaged configuration.

[0036] FIG. 11 is a perspective view of a valve pin holder installable in an injection molding apparatus in accordance with another embodiment of the present application.

[0037] FIG. 12 is a sectional view of the valve pin holder of FIG. 11 taken along line 12-12, shown installed in a schematic injection molding apparatus having a valve pin plate in the aligned position and the valve pin holder in the engaged configuration.

[0038] FIG. 13 is a sectional view of FIG. 11 with the valve pin plate in the open position, and the valve pin holder in the disengaged configuration.

[0039] FIG. 14 is a perspective view of a valve pin holder installable in an injection molding apparatus in accordance with yet another embodiment of the present application. [0040] FIG. 15 is a sectional view of the valve pin holder of FIG. 14 taken along line 15-15, shown installed in a schematic injection molding apparatus having a valve pin plate in the aligned position and the valve pin holder in the engaged configuration.

[0041] FIG. 16 is a sectional view of FIG. 15 with the valve pin plate in the open position and the valve pin holder in the disengaged configuration.

[0042] FIG. 17 is a perspective view of a valve pin holder installable in an injection molding apparatus in accordance with yet another embodiment of the present application.

[0043] FIG. 18 is a sectional view of the valve pin holder of FIG. 17 taken along line 18-18, shown installed in a schematic injection molding apparatus having a valve pin plate in the aligned position, and the valve pin holder in the engaged configuration.

[0044] FIG. 19 is a sectional view of FIG. 18 with the valve pin plate in the open position and the valve pin holder in the disengaged configuration.

[0045] FIG. 20 is a sectional view of the valve pin holder of FIG. 17 taken along line 20-20, shown installed in the schematic injection molding apparatus with the valve pin holder in the engaged configuration.

[0046] FIG. 21 is a perspective view of a valve pin holder installable in an injection molding apparatus in accordance with yet another embodiment of the present application.

[0047] FIG. 22 is a sectional view of the valve pin holder taken along line - of FIG. 21, shown installed in a schematic injection molding apparatus having a valve pin plate in the aligned position and the valve pin holder in the engaged configuration.

[0048] FIG. 23 is a sectional view of FIG. 22 with the valve pin plate in the open position and the valve pin holder in the disengaged configuration.

[0049] FIG. 24 is a perspective view of a valve pin holder installable in an injection molding apparatus in accordance with yet another embodiment of the present application.

[0050] FIG. 25 is a sectional view of the valve pin holder of FIG. 24 taken along line 25-25, shown installed in a schematic injection molding apparatus having a valve pin plate in the aligned position, and the valve pin holder in the engaged configuration. [0051] FIG. 26 is a sectional view of FIG. 25 with the valve pin plate the open position and the valve pin holder in the disengaged configuration.

DETAILED DESCRIPTION

[0052] Specific embodiments of the present invention are now described with reference to the figures. The following detailed description is merely exemplary in nature and is not intended to limit the scope of the application. In the following description, “downstream” is used with reference to the direction of molding material flow from an injection unit of an injection molding machine to a mold cavity of a mold of an injection molding system, and also with reference to the order of components or features thereof through which the molding material flows from the injection unit to the mold cavity, whereas “upstream” is used with reference to the opposite direction. In the following description, a reference number followed by the letter “s” indicates a schematic representation of a component or feature thereof associated with the reference number. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding field, background, summary or the following detailed description.

[0053] FIG. 1 is a sectional view of an injection molding apparatus 100 in accordance with an embodiment of the present application. Injection molding apparatus 100 delivers molding material received from a source (not shown) to a plurality of mold cavities 101s. Injection molding apparatus 100 includes a plurality of mold plates, for example a first mold plate 104, a second mold plate 106, a third mold plate 108, and a fourth mold plate 109 within and between which a hot runner system 110 is located. Mold plates 104, 106, 108, 109 include cooling channels, such as cooling channel 112 within third mold plate 108, through which cooling fluid is circulated to maintain injection molding apparatus 100 at a suitable molding temperature. As is commonly known, mold plates 104, 106, 108, 109 are held together by fasteners (not shown), and may also include additional fastening and/or aligning components such as guide pins, guide bushings etc. as would be understood by one of ordinary skill in the art. While four mold plates 104, 106, 108, 109 are shown, injection molding apparatus 100 can include other than four mold plates.

[0054] Hot runner system 110 distributes an incoming stream of molding material to mold cavities 101s. Hot runner system 110 includes a manifold 114, a plurality of nozzles 115, and a plurality of valve pins 116 which are translatable between an open position and a closed position to control the flow of molding material into mold cavities 101s. Manifold 114 divides the incoming melt stream into a plurality of outgoing melt streams, each of which is delivered to a respective mold cavity 101s via a respective nozzle 115. Manifold 114 is received in a manifold pocket 118 in third mold plate 108 which is enclosed by second mold plate 106. Manifold 114 includes a manifold channel 120 extending between a manifold inlet 121 (partially visible and shown in phantom) and a manifold outlet 122. Each nozzle 115 is received in a respective nozzle well 124 which extends from manifold pocket 118, through third mold plate 108, and into fourth mold plate 109. Each nozzle 115 includes a nozzle channel 125 extending therethrough. At its upstream end, each nozzle channel 125 is in fluid communication with manifold channel 120 via a respective manifold outlet 122, and at its downstream end, each nozzle channel 125 is in fluid communication with a respective mold cavity 101s via a mold gate 126s. Valve pins 116 extends through respective nozzle channels 125 to mold gates 126s.

[0055] Hot runner system 110 further includes a valve plate assembly 127 to which the plurality of valve pins 116 are coupled. Valve plate assembly 127 includes a valve pin plate 128 which is coupled to an actuator 129 which, in operation, axially moves valve pin plate 128 and valve pins 116 coupled thereto between at least two positions, for example, between an open position in which valve pins 116 are separated from mold gates 126s to permit molding material to pass through mold gates 126s and into mold cavities 101s and a closed position in which valve pins 116 block mold gates 126s to prevent molding material from entering mold cavities 101s. As shown, actuator 129 is shown as a two-position actuator, alternatively (not shown) actuator 129 is configured to move valve pin plate 128 to one or more positions other than the open position and the closed position. In FIG. 1, valve pin plate 128 and valve pins 116 are in the closed position.

[0056] Valve plate assembly 127 is received within an enclosure 130 defined by first mold plate 104 and second mold plate 106. Valve plate assembly 127 includes valve pin plate 128 and a plurality of valve pin holders 133 which are secured to valve pin plate 128 and coupled to valve pins 116. In the illustrated embodiment of FIG. 1, a portion of each valve pin holder 133 is secured in a respective holder bore 134 in valve pin plate 128 and valve pin plate 128 includes a valve plate access passage 135 which extends laterally therethrough and intersects holder bore 134.

[0057] A lateral bore 136 extends into valve pin holder 133 from an outer surface 138 thereof, and a coupling shaft 139 is received in lateral bore 136. Coupling shaft 139 is selectively axially positionable, relative to an axis of lateral bore 136, within lateral bore 136 between an engaged position in which valve pin 116 is physically coupled to valve pin plate 128 by coupling shaft 139 (see FIGS. 1-3) and a disengaged position in which valve pin 116 is physically decoupled from valve pin plate 128 (see valve pin holder 133a in FIG.4 and valve pin holder 133b in FIG. 5). In the engaged position, valve pin 116 is physically coupled to valve pin plate 128 by valve pin holder 133. In the disengaged position, valve pin 116 is physically decoupled from valve pin plate 128. Valve pin holder 133 includes a socket 145 and a plug 146, plug 146 reciprocable relative to socket 145. When coupling shaft 139 is in the engaged position, plug 146 cannot axially move relative to socket 145 (i.e., moving actuator 129 will move valve pin plate 128, plug 146, and socket 145 in unison) and when coupling shaft 139 is in the disengaged position, plug 146 can move axially relative to socket 145 (i.e., moving actuator 129 from the closed position to the open position will not also move plug 146 to the open position). When coupling shaft 139 is in the engaged position valve pin holder 133 can be described as being in an engaged configuration. Conversely, when coupling shaft 139 is in the disengaged position, valve pin holder 133 can be described as being in a disengaged configuration.

[0058] Injection molding apparatus 100 includes a mold plate access passage 140 that extends from a peripheral side 142 of injection molding apparatus 100 to enclosure 130. Mold plate access passage 140 has a sightline view of a proximal end 144 of coupling shaft 139 when valve pin plate 128 is in an aligned position. The aligned position can be any position. In the illustrated embodiments shown herein, mold plate access passage 140 is formed so that the aligned position of valve pin plate 128 is the closed position of valve pin plate 128. However, the aligned position can be other positions such as when valve pin plate 128 is in the open position or an intermediate position between the open and closed positions of valve pin plate 128. Mold plate access passage 140 can be formed within a mold plate of injection molding apparatus 100 or between mold plates of injection molding apparatus 100. In the illustrated embodiment of FIG. 1, mold plate access passage 140 is a bore that extends from a peripheral side of second mold plate 106 to enclosure 130. Mold plate access passage 140 allows an operator to physically decouple valve pin 116 from valve pin plate 128 by inserting a tool (not shown in FIG. 1) through mold plate access passage 140 to move coupling shaft 139 from the engaged position to the disengaged position while injection molding apparatus 100 remains coupled between platens of an injection molding machine (not shown). [0059] Referring now to FIGS. 2 and 3 in which FIG. 2 is an enlarged view of a portion P of FIG. 1, and FIG. 3 is the enlarged view of the portion P of FIG. 1 showing valve pin plate 128 in the open position. In the illustrated embodiment of FIGS. 1-3, injection molding apparatus 100 includes a valve pin holder 133a in accordance with an embodiment of the present application, and a valve pin holder 133b in accordance with another embodiment of the present application. Valve pin holders are referred to generically herein as valve pin holder 133. Socket 145 is received in holder bore 134 and is physically coupled to valve pin plate 128 so as to move therewith. Socket 145 defines a pocket 148 in which plug 146 is received. In the illustrated embodiments shown herein, valve pin 116 is releasably coupled to plug 146 by a hollow fastener 149 threadably coupled to plug 146; however, other coupling connections between valve pin 116 and plug 146 are contemplated. For example, valve pin 116 can be releasably coupled to plug 146 by a “T” slot (not shown) formed in a downstream end of plug 146 in which a head 151 of valve pin 116 is laterally received.

[0060] Referring to FIG. 2, lateral bore 136 includes a socket bore 152 that extends through socket 145 and a plug bore 154 which extends through plug 146. In the illustrated embodiment of FIG. 1, socket bore 152 includes a proximal socket bore portion 155 and a distal socket bore portion 156, and plug bore 154 includes a distal plug bore portion 157, at least a portion of which is threaded 158, and a proximal plug bore portion 160. Distal plug bore portion 157 is diametrically smaller than proximal plug bore portion 160 so as to define a step 162 between distal plug bore portion 157 and proximal plug bore portion 160.

[0061] Continuing with FIG. 2 and referring to FIG. 3, in the illustrated embodiment of FIG. 1 coupling shaft 139 includes a shank 163, a head 164, and a shoulder 165 between shank 163 and head 164. At its distal end 166, coupling shaft 139 includes an alignment portion 168. Head 164 is received in proximal plug bore portion 160 (see FIG. 2) and includes a screw-drive 169, for example, an internal polygon drive such as a hex socket or an external polygon drive such as a 12- point drive, at proximal end 144. Mold plate access passage 140 has a sightline view of screwdrive 169 when valve pin plate 128 is in the aligned position.

[0062] Shank 163 is received in distal plug bore portion 157 (see FIG. 2) and includes threads 170 sized to mate with distal plug bore portion 157 (see FIG. 2). Alignment portion 168 is sized to closely mate with distal socket bore portion 156 (see FIG. 2). In the illustrated embodiment of FIGS. 2 and 3, alignment portion 168 is a threadless circumferential surface of shank 163. When coupling shaft 139 is in the engaged position, alignment portion 168 is received in distal socket bore portion 156 whereby plug 146 and socket 145 are physically coupled together so that as valve pin plate 128 is translated between the closed position, shown in FIG. 2, and the open position, shown in FIG. 3, valve pin plate 128 and valve pin 116 move in unison. In the illustrated embodiment of FIG. 1, step 162 limits the extent shoulder 165 can travel in plug bore 154.

[0063] Valve pin holder 133b differs from valve pin holder 133a in that valve pin holder 133b includes a coupling shaft access passage 172 that extends axially therethrough. Mold plate access passage 140 has a sightline view, through valve plate access passage 135 and coupling shaft access passage 172, to proximal end 144 of coupling shaft 139a when valve pin plate 128is in the aligned position (see FIG. 2).

[0064] If valve pin 116 coupled to valve pin holder 133a needs to be physically decoupled from valve pin plate 128, an operator pauses operation of injection molding apparatus 100 with valve pin plate 128 positioned such that mold plate access passage 140 is aligned with valve plate access passage 135 (i.e. in the aligned position). The operator then inserts a suitable tool (not shown) sized to mate with screw-drive 169 through mold plate access passage 140, into valve pin plate access passage 135, across coupling shaft access passage 172, and into lateral bore 136 to engage with screw-drive 169. (That is, coupling shaft access passage 172 is dimensioned to allow a tool to pass through to engage screw-drive 169 for rotating coupling shaft 139 to linearly displace coupling shaft 139 within lateral bore 136.) Upon engaging the tool with screw-drive 169, the tool can then rotate coupling shaft 139 to withdraw alignment portion 168 from distal socket bore portion 156 (i.e., the disengaged position) with valve pin 116 physically decoupled from valve pin plate 128.

[0065] In the disengaged position, when valve pin plate 128 is translated from the closed position, shown in FIG. 2 to the open position, shown in FIG. 4, which is the enlarged view of the portion P of FIG. 1 showing valve pin plate 128 in the open position, which in the illustrated embodiment of FIG. 4, is also the misaligned position of valve pin plate 128, and valve pin holder 133a in the disengaged configuration, plug 146 slides within pocket 148 (depending on the application, heaters for the nozzle of the disengaged valve pin may need to be turned off so that the molding material in the nozzle can solidify and cease the valve pin) and valve pin 116 is independent from axial translation movement of valve pin plate 128.

[0066] Alternatively, if valve pin 116 coupled to valve pin holder 133b needs to be physically decoupled from valve pin plate 128 an operator can pause operation of injection molding apparatus 100 with valve pin plate 128 positioned such that mold plate access passage 140 is aligned with valve plate access passage 135 and halt heat input to the nozzle 115 associated with valve pin holder 133b. The operator can then insert a suitable tool (not shown) sized to mate with screwdrive 169 of coupling shaft 139b through mold plate access passage 140, into valve pin plate access passagel35, and into lateral bore 136 of coupling shaft 139b to engage with screw-drive 169 at proximal end 144b of coupling shaft 139b. Upon engaging the tool with screw-drive 169, the operator can then rotate coupling shaft 139b to withdraw coupling shaft 139b from socket bore 152, whereby coupling shaft 139b is moved to the disengaged position and valve pin 116 is physically decoupled from valve pin plate 128.

[0067] In this configuration, when valve pin plate 128 is translated from the closed position, shown in FIG. 2, to the open position, as shown in FIG. 5 which is the enlarged view of the portion P of FIG. 1 showing valve pin plate 128 in the open position and valve pin holder 133b in the disengaged configuration, valve pin 116 is independent from axial translation movement of valve pin plate 128.

[0068] In the illustrated embodiments of FIGS. 1-5, when coupling shaft 139 is in the engaged position, socket 145 axially overlaps plug 146 by an amount, which is greater than an axial translation distance of valve pin plate 128 as it moves between the closed and open positions. This configuration maintains a longitudinal overlap between plug 146 and socket 145 whether valve pin plate 128 is in the open or closed positions or valve pin holder 133 is in its engaged or disengaged configurations.

[0069] In the illustrated embodiments of FIGS 1-5, valve pin holder 133 includes a disengagement limiter 174 (see FIG. 2) which limits the axial retraction distance of coupling shaft 139 from lateral bore 136 to prevent disengagement between internal and external threads of plug bore 154 and coupling shaft 139. As shown, disengagement limiter 174 is a circlip received in a circumferential groove 175 in proximal plug bore portion 160. Disengagement limiter 174 is spaced apart from proximal end 144 of coupling shaft 139 by an amount that prevents threaded disengagement of coupling shaft 139 from plug bore 154 when coupling shaft 139 is in the disengaged position.

[0070] Referring to FIGS. 6 - 8 in which FIG. 6 is a perspective view of a valve pin holder 133c installable in an injection molding apparatus in accordance with yet another embodiment of the present application; FIG. 7 is a sectional view of valve pin holder 133c of FIG. 6 taken along line 7-7, shown installed in a schematic injection molding apparatus 100s having a valve pin plate 128s in the aligned position, and valve pin holder 133c in the engaged configuration; and FIG. 8 is the sectional view of FIG.7 having a valve pin plate 128s in the open position, and valve pin holder 133c in the disengaged configuration. Valve pin holder 133c includes a disengagement indicator 176 which offers tactile feedback to an operator that coupling shaft 139c is in the disengaged position. In the illustrated embodiment of FIGS. 6-10, disengagement indicator 176 is provided in the form of an O-ring 177, received in an inner circumferential groove 178 in a proximal plug bore portion 160c, and an outer circumferential groove 180 in head 164c of coupling shaft 139c.

[0071] Referring to FIG. 7, when coupling shaft 139c is in the engaged position, proximal end 144c of coupling shaft 139c is adjacent to O-ring 177 and outer circumferential groove 180 is axially offset from inner circumferential groove 178. When an operator begins to reposition coupling shaft 139c from the engaged position (see FIG. 7) to the disengaged position (see FIG. 8), O-ring 177 becomes compressed between coupling shaft head 164c and proximal plug bore portion 160c resulting in friction between coupling shaft head 164c and O-ring 177 as coupling shaft 139c is repositioned. Referring to FIG. 8, once coupling shaft 139c is repositioned to the disengaged position, O-ring 177 expands into outer circumferential groove 178 which reduces friction between O-ring 177 and coupling shaft head 164c by an amount that is likely noticeable by an operator. This reduction in friction creates a tactile indication that coupling shaft 139c is in the disengaged position.

[0072] In addition to providing tactile feedback to an operator about the position of coupling shaft 139c, friction between O-ring 177 and proximal plug bore portion 160c reduces the likelihood of coupling shaft 139c being dislodged from the engaged position during operation of injection molding apparatus 100s.

[0073] In the illustrated embodiments shown herein, valve pin holder 133 has a keyed connection with valve pin plate 128. That is, valve pin holder 133 is secured within injection molding apparatus 100 in a manner which maintains the sightline view, through mold access passage, to proximal end 144 of coupling shaft 139 when valve pin plate 128 is in the aligned position.

[0074] Referring now to FIGS 6, 9, and 10 in which FIG. 9 is a sectional view of valve pin holder 133c of FIG. 6 taken along line 9-9, shown installed in schematic injection molding apparatus 100s having valve pin plate 128s in the aligned position, and valve pin holder 133c in the engaged configuration, and FIG. 10 is a sectional view of valve pin holder 133c of FIG. 6 taken along line 10-10, shown installed in schematic injection molding apparatus 100s having valve pin holder 133c in the engaged configuration. In the illustrated embodiment of FIG. 6, a keyed connection between valve pin holder 133c and valve pin plate 128s is realized by securing the angular orientation of plug 146c relative to socket 145c and securing the angular orientation of socket 145c relative to valve pin plate 128s.

[0075] Referring to FIG. 9, angular orientation of plug 146c relative to socket 145c is maintained by a locating shaft 181 that projects laterally from plug 146c, and a locating slot 182 that extends through socket 145c to pocket 148c from a downstream end of socket 145c. Locating shaft 181 is received in locating slot 182 when plug 146c is installed in socket 145c. Locating shaft 181 and locating slot 182 are sized to prevent or limit rotation of plug 146c within pocket 148c while still maintaining the sightline view, through mold access passage (not visible in FIG. 9), to proximal end 144c of coupling shaft 139c when valve pin plate 128s is in the aligned position. Locating shaft 181 and locating slot 182 are also sized to permit axial movement of socket 145c relative to plug 146c when valve pin holder 133c is in the disengaged configuration and valve pin plate 128s is moved between the open and closed positions. In an alternative embodiment (not shown) angular orientation of plug 146c relative to socket 145c is maintained by forming plug 146c and pocket 148c to have complementary D-shaped cross-sections.

[0076] Referring to FIG. 10, angular orientation of socket 145c relative to valve pin plate 128s is maintained by a fastener 184 that extends through a lip 185 at an upstream end of socket 145c and is received in a bore 186 in valve pin plate 128s. As shown, fastener 184 includes a locating shank 187 that mates with both of a locating bore 188 that extends through lip 185 and a locating portion 190 of bore 186 in valve pin plate 128s. In this arrangement, fastener 184 secures the angular orientation of socket 145c relative to valve pin plate 128s and also axially secures socket 145c within holder bore 134s. In an alternative embodiment (not shown) the angular orientation of socket 145c relative to valve pin plate 128s is realized by a dowel that extends between socket 145c and valve pin plate 128s, and socket 145c is axially secured within holder bore 134s by fasteners that are independent from securing the angular orientation of socket 145c relative to valve pin plate 128s.

[0077] Referring to FIGS. 11 - 13 in which FIG. 11 is a perspective view of a valve pin holder 133d installable in an injection molding apparatus in accordance with yet another embodiment of the present application; FIG. 12 is a sectional view of valve pin holder 133d of FIG. 11 taken along line 12-12, shown installed in a schematic injection molding apparatus 100s having a valve pin plate 128s in the aligned position, and valve pin holder 133d in the engaged configuration; and FIG. 13 is a sectional view of FIG. 11 with valve pin plate 128s in the open position, and valve pin holder 133c in the disengaged configuration. Valve pin holder 133d is suitable for applications where it may not be feasible to include an access passage in valve pin plate 128s. In the illustrated embodiment of FIGS. 11-13, mold plate access passage 140s is located in second mold plate 106s, which is downstream from valve pin plate 128s. Valve pin holder 133d is received in holder bore 134s in valve pin plate 128s, and socket 145d and plug 146d extend downstream from valve pin plate 128s and into a downstream clearance bore 190s in second mold plate 106s. Lateral bore 136d and coupling shaft 139d are spaced apart from valve pin plate 128s and aligned with mold access passage 140s when valve pin holder 133d is in the engaged configuration and valve pin plate 128s is in the aligned position.

[0078] Also shown in the illustrated embodiment of FIG.11, socket 145d includes a plurality of locating slots 182dl, 182d2, 182d3, 182d4 and a plurality of distal socket bore portions 156dl, 156d2, 156d3. Locating slots 182dl-4 are angularly spaced apart by an angle a and extend through socket 145d, to pocket 148d from a downstream end of socket 145d. distal socket bore portions 156dl -3 are angularly spaced apart by angle a and are offset from locating slots 182dl-4 by, for example an amount equal to a H.

[0079] When plug 146d is received in pocket 148d, and locating shaft 181d (which extends laterally from plug 146d) is received in one of locating slots 182dl-4 (for example locating slot 182dl as shown in FIG. 11), distal plug bore portion (not visible in FIG. 11) and coupling shaft 139d received therein are axially aligned with distal socket bore portion 156dl. Locating shaft 181 d is receivable in any one of locating slots 182dl-4 to orient the angular position of plug 146d relative socket 145d about the axis of the valve pin holder.

[0080] Locating slots 182dl-d4 and distal socket bore portions 156dl-3 allow coupling shaft 139d to be oriented relative to socket 145d at a plurality of discrete angular orientations when socket 145d is secured to valve pin plate 128s. This configuration allows valve pin holder 133d to be used in applications where the injection molding apparatus includes a plurality of mold plate access passages at different angular orientations to the peripheral side(s) of the mold plate(s) from which the plurality of mold plate access bores extend.

[0081] Referring to FIGS. 14 - 16 in which FIG. 14 is a perspective view of a valve pin holder 133e installable in an injection molding apparatus in accordance with yet another embodiment of the present application; FIG. 15 is a sectional view of valve pin holder 133e of FIG. 14 taken along line 15-15, shown installed in a schematic injection molding apparatus 100s having a valve pin plate 128s in the aligned position, and valve pin holder 133e in the engaged configuration; and FIG. 16 the sectional view of FIG. 15 with valve pin plate 128s in the open position, and valve pin holder 133e in the disengaged configuration. Valve pin holder 133e is suitable for applications where it may not be feasible to include an access passage in valve pin plate 128s. In the illustrated embodiment of FIGS. 14-16, mold plate access passage 140s is located in first mold plate 104s, which is upstream from valve pin plate 128s. Valve pin holder 133e is received in holder bore 134s in valve pin plate 128s, and socket 145e and plug 146e extend upstream from valve pin plate 128s and into an upstream clearance bore 191s in first mold plate 104s. Lateral bore 136e and coupling shaft 139e are spaced apart from valve pin plate 128s and aligned with mold access passage 140s when valve pin holder 133e is in the engaged configuration and valve pin plate 128s is in the aligned position.

[0082] Referring to FIGS. 17 - 19 in which FIG. 17 is a perspective view of a valve pin holder 133f installable in an injection molding apparatus in accordance with yet another embodiment of the present application; FIG. 18 is a sectional view of valve pin holder 133f of FIG. 17 taken along line 18-18, shown installed in a schematic injection molding apparatus 100s having a valve pin plate 128s in the closed position, and valve pin holder 133f in the engaged configuration; and FIG. 19 the sectional view of FIG. 18, shown installed in schematic injection molding apparatus 100s having valve pin plate 128s in the open position, and valve pin holder 133f in the disengaged configuration. Valve pin holder 133f includes a plug 146f physically coupled to valve pin plate 128s and a socket 145f in which plug 146f is received. In the illustrated embodiment of FIGS. 17- 19, valve pin 116 is releasably coupled to socket 145f.

[0083] Continuing with FIG. 17 and referring to FIG. 20, which is a sectional view of valve pin holder 133f of FIG. 17 taken along line 20-20, shown installed in schematic injection molding apparatus 100s and with valve pin holder 133f in the engaged configuration. A keyed connection between valve pin holder 133f and valve pin plate 128s is accomplished by securing the angular orientation of socket 145f relative to plug 146f and securing the angular orientation of plug 146f relative to valve pin plate 128s. Angular orientation of socket 145f relative to plug 146f is maintained by a locating shaft 18 If that projects laterally from plug 146f, and a locating slot 182f that extends through socket 145f to pocket 148f from an upstream end of socket 145 into pocket 148f. Locating shaft 18 If is received in locating slot 182f when plug 146f is installed in socket 145f. Locating shaft 18 If and locating slot 182f are sized to limit or prevent rotation of socket 145f around plug 146f. Locating shaft 18 If and locating slot 182f are also sized to permit axial movement of socket 145f relative to plug 146f when valve pin holder 133f is in the disengaged configuration and valve pin plate 128s is moved between the open and closed positions.

[0084] Referring to FIGS. 17 and 18, angular orientation of plug 146f relative to valve pin plate 128s is maintained by a fastener 184f that extends across a lip 185f at the upstream end of plug 146. Fastener 184f is received in a bore (not visible in FIG. 18) in valve pin plate 128s and also axially secures valve pin holder 133f to valve pin plate 128s. The angular orientation of plug 146f relative to valve pin plate 128s can be further maintained by a dowel (not shown) that extends between lip 185fand valve pin plate 128s. Also shown in FIG. 18, at proximal end 144f of coupling shaft 139f includes an alignment portion 168f which mates with proximal socket bore portion 156f when valve pin holder 133f is in the engaged position.

[0085] Referring to FIGS. 21 to 23 in which FIG. 21 is a perspective view of a valve pin holder 133g installable in an injection molding apparatus in accordance with yet another embodiment of the present application; FIG. 22 is a sectional view of valve pin holder 133g taken along line 22- 22 of FIG. 21 shown installed in a schematic injection molding apparatus 100s having a valve pin plate 128s in the aligned position, and valve pin holder 133g in the engaged configuration; and FIG. 23 is the sectional view of FIG. 22 with valve pin plate 128s in the open position, and valve pin holder 133g in the disengaged configuration. Valve pin holder 133g includes a plug 146g which is slidably received in a holder bore 134s in valve pin plate 128s. Valve pin plate 128s includes a valve plate access passage 135s which extends laterally into valve pin plate 128s and intersects holder bore 134s. Lateral bore 136g includes a plug bore 154g that extends through plug 146g in which a coupling shaft 139g is received. At its distal end, coupling shaft 139g includes an alignment portion 168g which is sized to closely mate with valve plate access passage 135s. When coupling shaft 139g is in the engaged position (see FIG. 21), dowel portion 168g is received in valve plate access passage 135s whereby plug 146g and valve pin plate 128s are physically coupled together so that as valve pin plate 128s is translated between the closed and open positions valve pin holder 133g and valve pin plate 128s move in unison. When coupling shaft 139g is in the disengaged position (see FIG. 23, dowel portion 168g is retracted from valve pin access passage 135s whereby plug 146g and valve pin plate 128s are physically decoupled so that as valve pin plate 128s is translated between the closed and open positions, valve pin 116 is independent from the movement of valve pin plate 128s.

[0086] Referring to FIG. 21, valve pin holder 133g includes a locating shaft 181 that projects laterally from plug 146g and is received in a locating slot (not visible in FIGS. 21-23) in valve pin plate 128s whereby valve pin holder 133g is aligned relative to valve pin plate 128s.

[0087] Referring to FIGS. 24 - 26 in which FIG. 24 is a perspective view of a valve pin holder 133h installable in an injection molding apparatus in accordance with yet another embodiment of the present application; FIG. 25 is a sectional view of valve pin holder 133h of FIG. 24 taken along line 25-25, shown installed in a schematic injection molding apparatus 100s having a valve pin plate 128s in the aligned position, and valve pin holder 133c in the engaged configuration; and FIG. 26 is the sectional view of FIG. 25 with valve pin plate 128s in the open position, and valve pin holder 133h in the disengaged configuration. Referring to FIG. 25, valve pin holder 133h provides tactile feedback to an operator that coupling shaft 139h is in its engaged or disengaged position. Valve pin holder 133h includes a lateral bore 136h which includes a socket bore 152h that extends through socket 145h and a plug bore 154h that extends through plug 146h. Socket bore 152h includes a proximal socket bore portion 155h, and a distal socket bore portion 156h in which a coupling shaft 139h is received when coupling shaft 139h is in the engaged position. Plug bore 154h includes a distal plug bore portion 157h, at least a portion of which is threaded, and a proximal plug bore portion 160. Distal plug bore portion 157h is diametrically greater than proximal plug bore portion 160h so as to define a step 162h between distal plug bore portion 156h and proximal plug bore portion 160h.

[0088] Continuing with FIG. 25 and referring to FIG. 26, coupling shaft 139h includes a shank 163h, an alignment portion 168h at its distal end, and a shoulder 165h between alignment portion 168h and shank 163h. Shank 163h is threadably received in distal plug bore portion 156h Alignment portion 168h is sized to closely mate with distal socket bore portion 156h. When coupling shaft 139h is in the engaged position, alignment portion 168h is received in distal socket bore portion 155h whereby plug 146h and socket 145h are physically coupled together so that as valve pin plate 128s is translated from between the closed position and the open position, valve pin 116 and valve pin plate 128s move in unison. Coupling shaft 139h is repositioned between its engaged and disengaged positions by inserting a tool (not shown) through proximal socket and plug bore portions 155h, 160h to mate with screw-drive 169h (see FIG. 26) at a proximal end 144h of coupling shaft 139h whereby coupling shaft 139h can be rotated to move coupling shaft 139h between its engaged and disengaged positions.

[0089] In the illustrated embodiment of FIGS. 24-26, confirmation of coupling shaft 139h being in the engaged position (see FIG. 25) occurs when coupling shaft 139h is positioned such that shoulder 165h applies force against pocket 148h of socket 145h. Alternatively (not shown), valve pin holder 133h is formed so that confirmation of coupling shaft 139h being in the engaged position occurs when coupling shaft 139h is positioned such that distal end 166h of coupling shaft 139h applies force against holder bore 134h. Conversely, confirmation of coupling shaft 139h being in the disengaged position (see FIG. 26) occurs when coupling shaft 139h is positioned such that proximal end 144h applies force against step 162h.

[0090] Valve pin holder 133h further includes position holder 192 which reduces the likelihood of coupling shaft 139h being dislodged from the engaged or disengaged position. In the illustrated embodiment of FIGS. 24-26, position holder 192 is provided in the form of an O-ring 193 between distal plug bore portion 157h shank 163h of coupling shaft 139h. O-ring 193 creates friction between shank 163h and distal plug bore portion 157h, which reduces the likelihood of coupling shaft 139h being dislodged from the engaged position during operation of injection molding apparatus 100s.