FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)
TITLE OF THE INVENTION:


A SYSTEM AND METHOD OF PRELOADING THE TAPER
ROLLER BEARING IN MOULDING DIE
APPLICANT:
LARSEN & TOUBRO LIMITED
L&T House, Ballard Estate, P.O. Box No. 278,
Mumbai, 400 001, Maharashtra . INDIA.
PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

A) TECHNICAL FIELD
[0001] The present invention generally relates to molding die assembly and particularly to a component ejection mechanism in an injection molding system. The present invention more particularly relates to a preloading system for taper roller bearing in the component ejection mechanism.
B) BACKGROUND OF THE INVENTION
[0002] The ejection mechanism in an injection moulding setup should facilitate free translational and rotational motion of the sleeve. The resistance to the smooth motion of the sleeve can come from the frictional force arising due to the adhesion of the moulded component ejecting through the sleeve. In a typical injection moulding setup, a taper roller bearing caters to the axial and the radial load and facilitates smooth translational and rotational movement of the sleeve. To function effectively, the taper roller bearing also requires preloading. The preloading facilitates physical contact of bearing on the sleeve surface and restricts the vertical motion of the sleeve while facilitating its translational and the rotational motion. In the most commonly used injection moulding setup design, an external member is used to preload the taper roller bearing. The external member provides a static load. Even though the static load achieves the intended objective, it does suffer from an important design limitation. The limitation being the undesirable resistance to the motion of the sleeve due to constant force acting on it.

Additionally, the constant reaction force of the sleeve on the taper roller bearing also wears of the taper roller bearing due to friction and reducing its life time.
[0003] To address the design limitation and solve the mould functionality problem arising due to the static loading of the taper roller bearing on the sleeve a modification to the commonly used mould design is required. This additional component should provide for dynamic loading of the taper roller bearing on the sleeve surface. Hence there is a need for a preloading system for taper roller bearing in the molding die.
C) OBJECT OF THE INVENTION
[0004] The primary object of the invention is to provide a preloading system for a taper roller bearingin an injection mould apparatus.
[0005] Another object of the invention is to provide a preloading system for a taper roller bearing in an injection mould apparatus for dynamic loading of the tapered roller bearing on the sleeve surface.
[0006] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
D) SUMMARY OF THE INVENTION

[0007] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
[0008] The various embodiments of the invention provide a system and method for preloading the taper roller bearing in an injection molding device to provide unhindered and smooth motion of the sleeve during the ejection of a moulded component by the use of a combination of taper roller bearing and ball bearing assemblies.
[0009] According to one embodiment of the present invention, a ball bearing is provided on a bearing holder and connected to a taper roller through a sleeve surface to provide a preloading to the taper roller. The ball bearing is connected to a bearing puller mounted on the bearing holder through circlip thereby forming a sub assembly of the ball bearing. The sleeve is held by both the taper roller bearing and the ball bearing.
[0010] According to another embodiment of the present invention, a method for providing a preloading to the taper roller bearing is provided. According to the method, a ball bearing mounted on a bearing holder is connected to the taper roller bearing through a sleeve surface to provide a pre loading to the taper roller bearing. The ball bearing is connected to a bearing puller mounted on the bearing holder through circlip thereby forming a sub assembly of the ball bearing. The sleeve is supported by both the ball bearing and the taper roller bearing.


[0011] In the present invention ball bearing is used to preload taper roller bearing on the sleeve surface. Preloading by the ball bearing facilitates dynamic loading of taper roller bearing on the sleeve surface. This dynamic loading does not only facilitate free translational and rotational motion of the sleeve but also eliminates the undesired effects caused by a static force when used to preload the taper roller bearing on the sleeve surface. The undesirable effects is resistance to the motion of sleeve and wearing of the taper roller bearing.
[0012] When the ejector mechanism in an injection mould is actuated, the sleeve attached to this ejector mechanism starts moving along with it. At this time the moulded component which is stuck on a threaded core insert (a stationary member) also starts rotating. The rotational motion of the moulded component inside the sleeve facilitates its translational motion along the sleeve length because of a screw action. The ball bearing and taper roller bearing combination as described above facilitates the movement of sleeve freely in axial direction as well as in a rotational direction countering the sticking force of the moulded component to the sleeve walls. This smooth relative motion of moulded component and the sleeve causes smooth ejection of the moulded component. E) BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:


[0014] The other objects, features and advantages will occur to those skilled in the art from the following description of the embodiments and the accompanying drawings in which:
[0015] FIG.l shows the partial sectional view of the mould assembly provided with a preloading system for taper roller bearing according to one embodiment of the present invention.
[0016] FIG. 2 shows the enlarged partial sectional view of mould assembly of preloaded taper roller bearing with ball bearing according to one embodiment of the present invention.
[0017] Although specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0018] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the preferred embodiments that can be practiced is shown by way of illustrations. The embodiment is described in sufficient detail to enable those skilled in the art to practice the embodiment and it is to be understood that the logical, mechanical and other changes may be made without
31 MAR 2009

departing from the scope of the preferred embodiment. The following detailed description is therefore not to be taken in a limiting sense.
[0019] The various embodiments of the present invention provide a system and method for providing a preloading to the taper roller to provide a positive preloading on the taper roller.
[0020] According to one embodiment of the present invention, a ball bearing is provided on a bearing holder and connected to a taper roller through a sleeve surface to provide a preloading to the taper roller. The ball bearing is connected to a bearing puller mounted on the bearing holder through circlip to form a sub assembly of ball bearing. The sleeve is held by both the taper roller bearing and the ball bearing.
[0021] According to another embodiment of the present invention, a method for providing a preloading to the taper roller bearing is provided. According to the method, a ball bearing mounted on a bearing holder is connected to the taper roller through a sleeve surface to provide a pre loading to the taper roller. The ball bearing is connected to a bearing puller mounted on the bearing holder through circlip to form a sub assembly of ball bearing. The sleeve is supported by both the ball bearing and the taper roller bearing.
[0022] FIG. 1 shows the partial sectional view of the mould assembly provided with a preloading system for taper roller bearing according to one embodiment of the present invention. With respect to FIG. 1, The assembly includes a parallel 101, a punch housing
31 MAR 2009

102, an ejector plate 103, guide pins 104, a parallel 105, a taper roller bearing assembly 106, a ball bearing assembly 107, a sleeve 108, a core insert 109, a bearing puller 110, a bearing holder 111, a top plate 112 and the guiding bush 113 and a circlip 114.
[0023] The punch housing 102 and the top plate 112 are attached to each other through one parallel 101 and another parallel 105. The ejector plate 103 holds the guide pins 104. The guide pins 104 passing through the guiding bush 113 in the top plate 112 connects the ejector plate 103 to the taper roller bearing assembly 106 through ejector plate assembly. The circlip 114 attached to the ball bearing assembly 107 permit its rotation and prevent its lateral movement. The ball bearing assembly 107 is held in the mounting assembly by the bearing holder 111. The sleeve 108 which forms the casing of the core insert 109 is in physical contact with the tapered roller bearing assembly 106.
[0024] FIG. 2 shows the enlarged partial sectional view of mould assembly of preloaded taper roller bearing with ball bearing according to one embodiment of the present invention. With respect to FIG.2, The Mould is loaded on the injection-moulding machine. After all the required setting to run the mould is completed, moving half of the machine moves forward and butt against the fixed half of the mould. Now, plastic material is injected in the mould. After material sets inside the mould is opened. The moulded component at this stage of the operation is sticking to the threaded core insert 109 which is in the moving side of the injection moulding setup.


[0025] When the ejector mechanism is actuated, the sleeve 108 attached to this mechanism starts moving. The movement of the sleeve 108 is a combination of rotational and lateral motion. With the start of the ejection mechanism the moulded component also starts rotating. At this time the moulded component is stuck on the threaded core insert 109. The sleeve 108 starts pushing the component and the component is forced to move in the direction of the movement of sleeve 108. The smooth rotational and translational motion of the sleeve 108 which is facilitated by the tapered roller bearing 106 which in turn is dynamically preloaded by the ball bearing 107 causes a smooth relative sliding of the moulded component inside the threaded core insert 109. The moulded component moves translationally inside the core insert 109 and along the length of the sleeve 108 by the screw action and is ejected out of the injection moulding system.
G) ADVANTAGES OF THE INVENTION
[0026] The present invention uses a ball bearing assembly to preload a taper roller bearing assembly on the surface of the sleeve in an injection moulding apparatus. This kind of design facilitates dynamic preloading of the taper roller bearing. This dynamic loading of taper roller bearing on the sleeve restricts the vertical motion of the sleeve and also facilitates its resistance free axial and rotary movement.
[0027] Another advantage of the present invention is the increase in the life time of the taper roller bearing. This increase in the life time is achieved by the used of ball bearing to preload the taper roller bearing. Ball bearing provides a dynamic loading condition


which reduces the friction induced wear that is caused by the commonly used static loading condition.
[0028] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[0029] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the statements of the scope of the invention which as a matter of language might be said to fall there between.
RAKESH PRABHU
Patent Agent
Date: March 30, 2009. Place: Bangalore.

CLAIMS
What is claimed is:
1. A system for preloading taper roller in molding die including bearing mounting
assembly having taper roller bearings mounted on either side of the sleeves, the
system comprising:
a bearing holder; and
a ball bearing supported in the bearing holder;
wherein the ball bearing is connected to a taper roller bearing to provide
preloading to the taper roller bearing.
2. The system according to claim 1, wherein the ball bearing is connected to a taper roller bearing through a sleeve surface to provide additional loading to the taper roller.
3. The system according to claim 1, further comprising a bearing puller mounted on the bearing holder.
4. The system according to claim 1, wherein the bearing puller is connected to the ball bearing and to the sleeve mounted on a core insert in the mounting assembly so that the sleeve is held by both the ball bearing and the taper roller.
5. A method for preloading taper roller in molding die including bearing mounting assembly having taper roller bearings mounted on either side of the sleeves, the method comprising of:


providing a bearing holder; mounting a ball bearing on the bearing holder; and connecting the ball bearing to a taper roller bearing to provide a preloading.
6. The method according to claim 5. wherein the ball bearing is connected to the bearing holder and to the taper roller bearing through a sleeve surface.
7. The method according to claim 5, further comprising of providing a bearing puller for connecting with the ball bearing.
8. The method according to claim 7, wherein the bearing puller is connected to the ball bearing and to the sleeve through circlip to form a sub assembly of bearing so that the sleeve is held by the ball bearing and the taper roller bearing.
Dated this the 30th day of March 2009

RAKESH PRABHU
Patent Agent,
ALMT Legal,
#2, Lavelle Road, Bangalore-560 001
To,
The Controller of Patents, The Patent Office, Mumbai