Title of Invention

AN APPARATUS AND PROCESS FOR ASSEMBLING GARTER SPRING SEAL(S) IN A SEAL ASSEMBLY OF A MACHINE

Abstract

An apparatus (A) for assembling garter spring seal(s) in a seal assembly of a machine comprising: an adopter (1), a dummy shaft (2), said adopter having gradual and positive tapered entry portion (3), straight portion (4) & locating diameter (12), said dummy shaft having negative tapered outside diameter (6) & inside guiding diameter (5), said adopter is located in said dummy shaft, which takes guide of inside diameter (5) of said dummy shaft(2).

Full Text

FORM 2 THE PATENTS ACT, 1970 [39 OF 1970] COMPLETE SPECIFICATION [SEE SECTION 10 & RULE 13] 1 TITLE An apparatus and Process for assembling Garter spring Seal(s) in a seal assembly of a machine. 2 APPLICANT NAME MAHINDRA & MAHINDRA LTD. ADDRESS 1, GATEWAY BUILDING, APOLLO BUNDER, MUMBAI 400001 NATIONALITY INDIA The following specification particularly describes the nature of the invention and the manner in which it is to be performed:- Field of Invention : The present invention relates to process and means for assembling garter spring seal(s) or alike in between shaft and hole of a machine(s) housing to prevent the problem of seal lip damages while assembly. The said seal(s) is assembled to form a fluid-tight seal between outer peripheral surface of the shaft and inner peripheral surface of the machine(s) housing hole or visa-versa and at the same time to have relative motion between shaft and housing. Background of the Invention : A garter spring seal(s) or alike ( hereafter mentioned as seal(s)) is a vital component of seal assembly that has to retain the fluid and also allow relative motion between shaft and machine(s) housing with minimal frictional power loss. A seal(s) is used in a machine(s) having shaft extending through a wall of a machine(s) housing, so as to form fluid-tight seal between the outer peripheral surface of the shaft and inner peripheral surface of the machine(s) hole or visa-versa, allowing the shaft or housing to rotate with minimum friction. Failures of seal(s) assembly iead to poor performance or breakdown of the system(s) in which it is assembled. Also consequential failures in a machine(s) could be of higher severity than the failure of seal(s) depending on design, location and criticality of a function or system. Common seal(s) failures are because of, a) incorrect conjugate parts of seal assembly comprising shaft(s), machine(s) hole b) Worn out seal lip (complete or partial) c) Seal iip deformation and /' or lip fold and / or iip cut. It is observed after plotting performance curve for seal(s) for its life cycle based on the failures data, early failures of seai(s) (Infant mortality, 22) are usually because of product and process non-conformance as indicated in figure 1 (bath tub curve). In today's scenario advancement in terms of Statistical Process Control, POKAYOKE, Design Of Experiments or alike are in practice for improving product quality in all respect, which addresses the causes of failure as mentioned above in a and b. Whereas failures because of lip damages are still unsolved as they are mostly depend upon the assembly skills of the operator, existing assembly practices followed by the machine(s) manufactures (as per the guidelines given by seal manufactures) and complexity of seal assembly based on its geometry and access to the location, As per US 4,550,486 patent an oil seal mounting jig for mounting an oil seal in a hole formed in a wall of a machine(s) housing is developed to ensure the proper orientation of the oil seal while assembling, as it can not perform the desire sealing function unless it is mounted with recommended orientation (garter spring which is provided for the urging force on the oil seal lip to be always towards the oil contact area) in a hole of machine(s) housing. According to this invention desired orientation of an oil seal while assembling in machine(s) housing hole is taken care, where as the problem of lip deformation and or lip fold and or lip cut while assembling seal(s) in a seal assembly are not getting addressed. US patent 4,984,812 in which oil seal assembly is modified with reference to oil seal lip design being use for assembly. Oil seal lip is provided with flat surface having minor angle of 1deg 30min to 3deg C with respect to outer peripheral surface of the shaft on which it is being assembled. The spring is provided in such a way to give required urging force on a flat surface of oil seal lip to bring it into surface contact with the outer peripheral surface contact of the shaft. Where as in case of triangular shape lip design, while cutting operation of the lip neck neither a stable position for the lip not stable inner diameter is formed. There is also an offset between the line along which the urging force of the spring acts on the tip of the lip, thus retracting from oil seal performance. The above invention is applicable mainly for the reciprocating shaft(s) of a machine(s) and further relates with the design of oil seal lip. However the problem of seal lip deformation and / or lip folds and / or lip cut while assembling seal(s) is still not addressed. US patent 4,427,206 relates to oil seal assembly with an oil seal provided with a backup ring made of synthetic resin and seated in a gap formed between the inner peripheral surface of the lip neck portion and the reinforcement ring without being bounded to the lip neck portion and the reinforcement ring for backing up the lip neck portion of an elastic seal ring and further mode the backup ring with anti dust lip for preventing dust from coming into the machine housing. They're by avoiding the lip deformation while resilient sliding contact with the rotating shaft on which it is being assembled. The above invention addresses problem of seal lip deformation while operation of a machine(s) by modifying oil seal(s) lip neck design, whereas the problem of lip deformation and / or lip fold and / or lip cut while assembling seal(s) is not addressed. It is observed that machine manufacturer(s) have identified these seal(s) assembly failures because of lip deformation and / or lip fold and / or lip cut, also they have come up with improved oil seal lip neck design, assembling oil seal jig (ensures desired orientation in machine housing hole) to overcome these seal(s) failures. Whereas attempt on assembly practices particularly while locating seal lip neck at its desired position is not made. Therefore It's long standing need of machine(s) manufacturer(s) to flush out these early failures (22) of the seal(s) because of lip damages, contributed by existing assembly practices, assembly skills of the operator and complexity of seal assembly based on its geometry and access to the location. This will further cause poor performance of a machine(s), increases breakdown of system(s) and / or products(s) and ultimate effect of this will be loss of productivity, increase in warranty failures and customer dissatisfaction. All of this will have serious impact on company reputation / brand image. Summary of the Invention : The primary objective of present Invention is to avoid infant mortal failures of garter spring seal(s) or alike while assembling in machine(s). Whereas said seal(s) is assembled to form a fluid-tight seal between outer peripheral surface of the shaft and inner peripheral surface of the machine(s) hole or visa-versa with having relative motion between each other. Also it is the objective of the present invention to provide a means for assembling seal(s) in a machine(s), which will always ensure desired resting of seal(s) lip on a shaft or machine(s) hole, therefore prevents problem of seal lip deformation and / or lip fold and / or lip cut leading to early failure (22) of a seal(s) as shown in figure of bath tub curve (particularly because of improper assembly). It is another object of the present invention to avoid the necessity to pay a specific attention while assembling a Seal(s) in a machine(s) to ensure desired resting of seal lip, which creates a problem particularly in mass production where less time is available for the assembly. It is another object of this invention is to provide a solution for assembling seal(s) in a machine(s), where both access and visibility for aligning shaft and machine hole to have desired resting of seal lip is difficult due to complexity of seal assembly. It is an advantage of this invention is to minimize the dispatch time of a machine(s) after assembling and necessity testing. Whereas as current practices involves dismantling of seal assembly for checking leakage's because of seal lip deformation and / or lip fold and / or lip cut. Thus the aim of this invention to prevent poor performance of a machine(s), breakdown of a system(s) and / or machine(s) leading to reduce warranty failures, increase productivity and achieving customer satisfaction. Brief of discretion of the drawings : Figure 1 shows the schematic diagram of bathtub curve indicating performance curve of seal(s) failures in its life cycle based on failure data. Figure 2 shows an assembly means A, (adaptor and dummy shaft) used for assembling garter spring seal(s) or alike in between shaft and a machine(s) hole. Figure 3 shows assembling said seal(s) with dummy shaft on shaft of a machine(s) by means A. Figure 4 shows an another type of an assembly means B, used for assembling garter spring seal(s) or alike in between shaft and a machine(s) hole, where both excess and visibility to ensure desired resting of seal lip is difficult. Figure 5 shows blind seal(s) assembly of a machine(s) where both excess and visibility to ensure desired resting of a seal lip neck is not possible. Detail description of the preferred embodiment: As per the current practice of assembling garter spring seal(s) or alike on a shaft of a machine(s), protective sleeve is put on the guiding or spline outer diameter portion of shaft(s). Then seal with desired orientation (garter spring side towards oil compartment) is put at the entry portion of protective sleeve having taper for the gradual expansion of seal lip neck. A seal(s) is then slides over said entry portion, which is positive and gradually tapered to ensure equal peripheral expansion of lip neck. During sliding of seal over taper portion to overcome the frictional resistance between seal lip and protective sleeve outer diameter and same time to expand seal lip neck inner peripherally force need's to be applied, for which one has to rock a seal(s) in one or two planes. In this case reactive force acts on lip neck and lip-retaining spring (garter spring) is not able to hold the tip of the lip in desired position. This may finally result in to seal Lip deformation and / or folds and / or lip cut causing seal assembly failures. A Seal(s) in same state is then slides over the straight portion of the protective sleeve and then on the shaft where seal(S) takes its final position. Here the force required to slide the seal from straight portion of sleeve to final position on shaft is only the frictional resistance as there is no expansion of seal lip neck If due care is hot taken during sliding of seal on tapered portion of protective sleeve, there is possibility of seal lip neck may get damage. As there is no change in state till it reaches to final position on shaft of a machine(s), seals(s) lip remains in its deform and / or folded and / or cut condition. Machine(s) with such seal assembly will not function satisfactorily and / or stop functioning of the system(s). In case of difficulty for the access (blind assembly) to remove protective sleeve, existing sleeve can not be used for the a seal(s) assembly and at the same time existing protective sleeve has its own limitation as mentioned above. A garter spring seal(s) or alike assembly process with a means A as shown in figure 2 and 3, Means A, is made in two pieces that is adopter (1) and dummy shaft (2). While assembling a seal(s) with means A, first adopter (1), is kept in dummy shaft (2), which takes the guide of dummy shaft inner diameter (5) with reference to straight portion (4) and locating diameter (12) as shown in figure 2. Then a seal(s) (9) is kept at the start of positive and gradually taper entry portion (3) of adaptor (1), but this time orientation of seal(s) (9) will be exactly in reverse direction that of existing process as shown in figure 2 and 3, because of which reactive force is opposes by garter spring force. Hence won't be any kind of damage to seal lip neck. When seal (9) gets slide on the positive and gradually tapered entry portion (3) of adopter (1), here also rocking is necessary but this time reactive force due to sliding and expanding will be counteract by garter spring force. Which will also hold the tip of the lip on adopter taper portion (3) thereby avoid lip damages. After sliding seal (9) over straight portion (4) of adopter (1), seal (9) is then slides over the outer diameter (6) of dummy shaft (2), which is having negative taper say at position (10). Dummy shaft (2) (along with seal at position 10) after removing adopter (1) is then transferred with its reverse orientation on shaft (8) of a machine(s), where it take's guide of guiding outer diameter (7) of machine shaft (8) as shown in figure (3). A seal(s) is then hold at its final position (10) and dummy shaft (2) is moved back. As outer diameter (6) of dummy shaft (2) is having negative taper, thereby allowing seal lip neck to slides on negative taper and desired resting of seal(s) lip at its final position (10). A garter spring seal(s) or alike assembly process with a means B, as shown in figure 4 and 5 In the final assembly, if casing envelops a seal(s) then there is no access to remove the existing protective sleeve, also existing sleeve has drawback as mentioned, which puts the limitation on its use for seal(s) assembly. A type of blind seal(s) assembly is shown in figure 5. As per functional requirement seal (15) has to be assembled with desired orientation only that is garter spring side towards oil compartment (16) of the machine housing (17and18). As explained in previous section if there is against lip force (19) acts on the seal lip neck while assembly, then possibility of lip getting deform and / or fold and / or cut is very high. To overcome these assembly problems an assembling means B, as shown in figure 4 is inserted in seal lip inner periphery as shown in figure 5. Initially means B, is in a form of oval shape, which is getting rounded while inserting shaft (20) because of its inner taper portion (12). Machine(s) shaft (20) (enveloped by casing) is then inserted in means B, because of its inner taper portion (12), insertion of shaft gradually expands the seal lip neck, also contact between shaft and means B is minimum so that means B can be removed easily without disturbance to assembly fitment. Shaft after taking its final position in a seal(s) assembly as shown in figure 5, a means B is removed from the window (21) available anywhere insinuates of seal assembly area. Because of the taper (11) provided on a means B it is possible to have line contact between seal lip and taper portion (11), which allows easy removal of means B and desired resting of seal lip on machine(s) shaft Removal of a means B after seal assembly from the window is only possible due to feature of spit and / or pivot pin mechanism (13) and slot(s) (14) provided on means B. A said assembly means B helps in expanding oil seal lip inner periphery without any damage to seal lip neck, as there is no relative motion between inserting shaft (20) and oil seal lip neck. Thus assembly means B effectively work, when because of blind assembly, existing protective sleeve can not be used and at the same time to overcome the problems of existing protective sleeve for assembling a seal(s) in a machine(s). We claim: 1. An apparatus (A) for assembling garter spring seal(s) in a seal assembly of a machine comprising: an adopter (1), a dummy shaft (2), said adopter having gradual and positive tapered entry portion (3), straight portion (4) & locating diameter (12), said dummy shaft having negative tapered outside diameter (6) & inside guiding diameter (5), said adopter is located in said dummy shaft, which takes guide of inside diameter (5) of said dummy shaft(2). 2. A process of assembling garter spring seal in a seal assembly of a machine(s) using the apparatus as claimed in claim 1 comprising the following steps: entering said garter spring seal with it's reverse orientation from said gradual and positive tapered entry portion [3] of said adopter [1] to said outside diameter [6] of said dummy shaft[2]; removing said adopter [1] from said dummy shaft [2] after moving garter spring seal on said outside diameter[6] of apparatus A to position 10; locating said dummy shaft[2] along with said garter spring seal, after reversing it's direction on guiding diameter (7) of assembly shaft(s) [8] of said machine(s); moving back said dummy shaft[2] by holding said garter spring seal, thereby allowing seal lip to slide positively from said dummy shaft[2] to said machine shaft (8), 3. An apparatus as claimed in claim 1 used for assembling a garter spring seal[s] in between shaft and hole of a machine(s) housing, wherein said seal is assembled to form a fluid-tight sealing between outer peripheral surface of the said shaft and inner peripheral surface of the said machine(s) housing hole or visa-versa and at the same time having relative motion between each other with minimum friction. Dated this 2nd day of April 2004 TO THE CONTROLLER OF PATENTS THE PATENT OFFICE, MUMBAI MAHINDRA & MAHINDRA LTD. BY THEIR ADVOCATES-IP SHYAM SUNDER IYER PATENT AGENT TAS & CO.

Documents:

407-mum-2004-abstract(amanded)-(2-4-2004).pdf

407-mum-2004-abstract(granted)-(16-5-2007).pdf

407-mum-2004-cancelled pages(28-5-2005).pdf

407-mum-2004-claims(2-4-2004).pdf

407-mum-2004-claims(amanded)-(10-9-2004).pdf

407-mum-2004-claims(amanded)-(2-4-2004).pdf

407-mum-2004-claims(complete)-(2-4-2004).pdf

407-mum-2004-claims(granted)-(16-5-2007).pdf

407-mum-2004-claims(granted)-(28-5-2005).doc

407-mum-2004-claims(granted)-(28-5-2005).pdf

407-MUM-2004-CORRESPONDENCE 16-6-2008.pdf

407-mum-2004-correspondence(ipo)-(1-6-2007).pdf

407-mum-2004-correspondence(ipo)-(11-7-2007).pdf

407-mum-2004-correspondence(ipo)-(16-5-2007).pdf

407-mum-2004-correspondence1(11-4-2008).pdf

407-mum-2004-correspondence2(30-5-2005).pdf

407-mum-2004-description(complete)-(2-4-2004).pdf

407-mum-2004-description(granted)-(16-5-2007).pdf

407-mum-2004-drawing(2-4-2004).pdf

407-mum-2004-drawing(28-5-2005).pdf

407-mum-2004-drawing(amanded)-(10-9-2004).pdf

407-mum-2004-drawing(amanded)-(2-4-2004).pdf

407-mum-2004-drawing(amanded)-(28-5-2005).pdf

407-mum-2004-drawing(granted)-(16-5-2007).pdf

407-MUM-2004-FORM 1 16-6-2008.pdf

407-mum-2004-form 1(2-4-2004).pdf

407-mum-2004-form 13(18-5-2005).pdf

407-mum-2004-form 19(2-4-2004).pdf

407-mum-2004-form 2(2-4-2004).pdf

407-mum-2004-form 2(complete)-(2-4-2004).pdf

407-mum-2004-form 2(granted)-(16-5-2007).pdf

407-mum-2004-form 2(granted)-(28-5-2005).doc

407-mum-2004-form 2(granted)-(28-5-2005).pdf

407-mum-2004-form 2(title page)-(2-4-2004).pdf

407-mum-2004-form 2(title page)-(complete)-(2-4-2004).pdf

407-mum-2004-form 2(title page)-(granted)-(16-5-2007).pdf

407-mum-2004-form 26(2-4-2004).pdf

407-mum-2004-form 3(2-4-2004).pdf

407-mum-2004-form 5(2-4-2004).pdf

407-mum-2004-specification(amanded)-(28-5-2005).pdf

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