Injection moulding apparatus

Claim 2

Apparatus for injection moulding comprising a mould containing a mould cavity defined by at least two mould members including a first mould member and a second mould member, opposed to, and moveable relative to, said first mould member, moving means for moving said second mould member relative to said first mould member from the position wherein a moulding can be removed from the mould cavity to the position wherein the mould cavity is closed, and vice versa, whereby the distance between said first and second mould members may be varied, two injection means for injecting plastics material into the mould cavity, valve means disposed between said injection means and the mould cavity which can be switched between a first position wherein only the first injection means communicates with the mould and a second position wherein only the second injection means communicates with the mould cavity, mould control means for controlling the movement of said second mould member toward said first mould member, and valve control means for actuating the valve means to switch from said first position to said second position while said second mould member is moving towards said first mould member.

Claim 3

Apparatus as claimed in claim 1 wherein one of the first and second mould member is provided with at least one hydraulic ram with which the other of the first and second mould members is engageable under pressure, and means are provided to release hydraulic fluid from said at least one ram at a controlled rate.

Claim 4

Apparatus as claimed in claim 2 wherein triggering means are provided to initiate release of said hydraulic fluid, said fluid release triggering means being actuatable when said second mould member has moved to the position relative to said first mould member wherein the mould member, engageable with said at least one ram, engages with said at least one ram.

Claim 5

Apparatus as claimed in claim 1 wherein the valve means has a shut off position wherein neither injection means communicates with the mould cavity.

Claim 6

Apparatus as claimed in claim 4 wherein triggering means are provided to cause the valve means to switch from said shut off position to said first position, said valve triggering means being actuatable when said second mould member has moved to a predetermined position relative to said first mould member from the position wherein a moulding can be removed from the mould cavity.

Claim 7

Apparatus as claimed in claim 1 wherein triggering means, actuatable when a predetermined amount of material has been injected from the first injection means, are provided to cause the valve to switch from the first position to said second position.

Claim 8

Apparatus as claimed in claim 1 wherein triggering means, actuatable when a predetermined amount of material has been injected from the second injection means, are provided to cause the valve to switch from the second position to the first position.

Claim 9

Apparatus as claimed in claim 4 wherein triggering means, actuatable when the predetermined total amount of material has been injected from the first and second injection means, are provided to cause the valve to switch to the shut off position.

Claim 10

Apparatus as claimed in claim 8 wherein the triggering means actuatable to cause the valve to switch to the shut off position is also arranged to start a timer.

Claim 11

Apparatus as claimed in claim 9 wherein the timer is actuatable, after a predetermined length of time, to cause said second mould member to commence movement away from said first mould member.

Claim 12

Apparatus as claimed in claim 10 wherein triggering means, actuatable when said second mould member has moved away from said first mould member by a predetermined amount, are provided to stop movement of said second mould member.

Claim 13

Apparatus for injection moulding comprising: i. a mould containing a mould cavity defined by at least two mould members including a first mould member and a second mould member opposed to, and moveable relative to, said first mould member; ii. moving means for moving said second mould member relative to said first mould member from the position wherein a moulding can be removed from the mould cavity to the position wherein the mould cavity is fully closed, and vice versa, whereby the distance between said first and second mould members may be varied, one of said first and second mould members being provided with iii. at least on hydraulic ram positioned such that, at a predetermined position in the travel of the second mould member moveable relative to said first mould from the position wherein a moulding can be removed from the mould cavity towards the position wherein the mould cavity is fully closed, the other of said first and second mould members engages with said at least one hydraulic ram, and, after such engagement, the movement of said second member relative to said first mould member under the action of said moving means can be controlled by control of release of hydraulic fluid from said at least one hydraulic ram; iv. release means to permit controlled release of hydraulic fluid from said at least one hyraulic ram; v. first triggering means to trigger said release means, said first triggering means being actuated by said second mould member when it has moved to the position relative to said first mould member wherein the mould member, engageable with said at least one ram, engages with said at least one ram; vi. two injection means for injecting plastics material into the mould cavity; vii. valve means disposed between said injection means and the mould cavity, which valve means can be switched through a sequence of valve positions, which sequence includes switching from a first position wherein only the first injection unit communicates with the mould cavity to a second position wherein only the second injection unit communicates with the mould cavity; viii. control means for switching said valve means through said sequence of positions; and ix. second triggering means to trigger the control means to initiate the switching of the valve means through its sequence of positions, said second triggering means being actuated by said second mould member when it has moved to a predetermined position relative to said first mould member.

Claim 14

Apparatus for injection moulding comprising: i. a mould containing a mould cavity defined by at least two mould members including a first mould member and a second mould member opposed to, and moveable relative to, said first mould member; ii. moving means for moving said second mould member relative to said first mould member from the position wherein a moulding can be removed from the mould cavity to the position wherein the mould cavity is fully closed, and vice versa, whereby the distance between said first and second mould members may be varied, one of said first and second mould members being provided with iii. at least on hydraulic ram positioned such that, at a predetermined position in the travel of the second mould member moveable relative to said first mould from the position wherein a moulding can be removed from the mould cavity towards the position wherein the mould cavity is fully closed, the other of said first and second mould members engages with said at least one hydraulic ram, and, after such engagement, the movement of said second member relative to said first mould member under the action of said moving means can be controlled by control of release of hydraulic fluid from said at least one hydraulic ram; iv. release means to permit controlled release of hydraulic fluid from said at least one hyraulic ram; v. first triggering means to trigger said release means, said first triggering means being actuated by said second mould member when it has moved to the position relative to said first mould member wherein the mould member, engageable with said at least one ram, engages with said at least one ram; vi. two injection means for injecting plastics material into the mould cavity; vii. valve means disposed between said injection means and the mould cavity, which valve means can be switched through a sequence of valve positions, which sequence includes switching from a first position wherein only the first injection unit communicates with the mould cavity to a second position wherein only the second injection unit communicates with the mould cavity; viii. control means for switching said valve means through said sequence of positions; and ix. second triggering means to trigger the control means to initiate the switching of the valve means through its sequence of positions, said second triggering means being actuated by said second mould member when it has moved to a predetermined position relative to said first mould member.

Claim 15

Apparatus as claimed in claim 12 wherein said second triggering means is positioned such that it is actuated by said second mould member when second mould member is in a position which is after that where said opposed mould member, engageable with said at least one ram, engages with said at least one hydraulic ram, and after that position where the firt triggering means is actuated but which is before the first and second mould members reach the fully closed position.

Claim 16

Apparatus as claimed in claim 12 wherein the valve means has a shut-off position wherein neither injection means communicates with the mould cavity.

Claim 17

Apparatus as claimed in claim 14 wherein the injection means comprise rams reciprocatably mounted in barrels and the second triggering means triggers the control means to switch the valve from the shut-off position to the first position and third triggering means are provided, said third triggering means being actuated when thE ram of the first injection reaches a predetermined position and which triggers the control means to switch the valve from said first position to said second position.

Claim 18

Apparatus as claimed in claim 15 wherein fourth triggering means, actuatable when the ram of the second injection means reaches a predetermined position, is provided to trigger the control means to switch the valve from said second position to said first position.

Claim 19

Apparatus as claimed in claim 14 wherein triggering means, actuatable when the predetermined total amount of material has been injected from the first and second injection means, are provided to cause the valve to switch to the shut-off position.

Claim 20

Apparatus as claimed in claim 17 wherein the triggering means actuatable to cause the valve to switch to the shut-off position is also arranged to start a timer.

Claim 21

Apparatus as claimed in claim 18 wherein the timer is actuatable, after a predetermined length of time, to cause said second mould member to commence movement away from said first mould member.

Claim 22

Apparatus as claimed in claim 19 wherein triggering means, actuatable when said second mould member has moved away from said first mould member by a predetermined amount, are provided to stop movement of the second mould member.