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Patent Searching and Data


Title:
DUAL SPRING TENSIONER ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2017/158613
Kind Code:
A1
Abstract:
Embodiment of invention discloses a tensioner assembly. The tensioner assembly comprises dual springs such as a plunger-biasing spring and a retention spring that can contribute additively to the total force exalting the plunger in the protruding direction by the arrangement and specifications of the plunger-biasing spring and the retention spring.

Inventors:
GAWADE SHYAM BALRAM (IN)
VISPUTE SACHIN DATTATRAY (IN)
RATHOD RAGHUNATH BABU (IN)
MOHANTY LENIS (IN)
Application Number:
PCT/IN2017/000050
Publication Date:
September 21, 2017
Filing Date:
February 27, 2017
Export Citation:
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Assignee:
ADVIK HI-TECH PVT LTD (IN)
International Classes:
F16H7/08
Foreign References:
US6808466B22004-10-26
US4309174A1982-01-05
Attorney, Agent or Firm:
WANGE, Prafulla et al. (IN)
Download PDF:
Claims:
We Claim:

1. A tensioner 100 comprising:

a housing 102;

a plunger 106 wherein the plunger 106 is configured to slide and protrude from the housing 102;

a plunger-biasing spring 108 accommodated inside the housing 102 beneath the plunger 106 which is arranged to bias the plunger 106 in protruding direction;

a retentionspring 110 accommodated inside the housing 102 and arranged in way that the retentionspring 1 10 supplements the force to be exerted on the plunger by plunger-biasing spring 108 and also adapted to reduce noise issue by preventing matting of the plunger 106 and the housing 102.

The tensioner as claimed in claim 1, wherein a roller 104 configured to guide the plunger 106for supporting and controlling the drive of the plungerl06.

The tensioner as claimed in claim 1, wherein a spacer 1 12 is designed to retain the plunger-biasing spring 108 and the retention spring 1 10 separate to prevent bucking and/or entangling.

The tensioner as claimed in claim 1, wherein a spacer 1 12 is designed to guide one or both of the plunger-biasing spring 108 and the retention spring 110.

The tensioner as claimed in claim 1, wherein a spacer 1 12inc hides an upper shaft 1 12a, a disk 112d and a lower shaft 112b configured in a way to make the plunger 106 rest on the disk 1 12d.

6. The tensioner as claimed in claim 1, wherein a spacer is of disk shape which includes a disk 112d and optionally includes any or both of an upper shaft 112a anda lower shaft 112b, configured to prevent matting of the plunger-biasing spring 108with the retentionspring 1 10.

Description:
DUAL SPRING TENSIONER ASSEMBLY

FIELD OF INVENTION

The present invention relates to a tensioner assembly. More specifically, the present invention is relatedto a dual spring tensioner for two or three wheeled vehicles.

BACKGROUND OF INVENTION

In general, chain drives are used in motorcycle or other straddle type vehicles for the transmission of rotation. During transmitting the rotation from the driving shaft to a driven shaft, the chain/cam chain generally gets elongated due to thermal expansion. Because of this, it creates noise and which in turn discomforts the rider. Hence, it is important to maintain a certain degree of tension to the chain to prevent noises or slippage.

For this purpose, there are tensioner assemblies known in prior art that imparts load on the chain and prevents the chances of its slippage. Most of the existing tensioners include teeth for retraction of plunger inside the tensioner housing. However, they are lacking in providingcontinuous load to the chain and they are also not configured to retract the plunger and set back within the housing after installation. The conventional plungers are guided by surface teeth and restricted to move only in a forward direction.However, sometimes tension of the chain becomes excessive due to continuous reactive force applied by the chain over the tensioner than it became necessary to reduce the tension over the chain exerted by the tensioner.

Hence, in view of aforementioned, it is required to develop an improved tensioner that can overcome one or more limitations of the prior art. It is also required to devise the tensioner with high load specifications. SUMMARY OF INVENTION

For the purpose of addressing problems as discussed, present invention provides a tensioner which includes a plunger without teeth which is able to provide a smooth load graph. Further, the present invention recognized a problem that many such tensioner assemblies create noise during operation due to direct metal to metal interaction which creates inconvenience to the rider. Therefore, this problem is also addressed by the way of present invention.

Embodiment of invention discloses atensioner. The tensioner comprises a plunger, an apparatus for chain load measurement 100 comprises a housing 102, a rod 108, a spring 106 and a plunger 104. The apparatus for chain load measurement 100 further includes a metric scale 1 10 to measure the displacement of rod 108.

In an embodiment of the present invention, the rod 108 isslid-ably mounted in a hole of the housing 102 and biased by spring force within the housing 102. In FIG. 1A, the spring 106 is shown in wounded form and the rod 108 is in unreleased condition. In FIG. IB, the spring 106 is shown in unwounded form and the rod is in released condition, a hole for accommodating plunger and the housing dual springs such as a plunger-biasing spring and a retention spring. The plunger-biasing spring stores energy to bias the plunger for exalting force to the chain. It is an object of the present invention to provide a tensioner that can be used in arrangement with the crankcase inside transmission.

It is an object of the present invention to provide a tensioner that can contribute additively to the total force exalting the plunger in the protruding direction by the arrangement and specifications of the plunger-biasing spring and the retention spring.

It is another object of the present invention to provide a tensioner with reduced (no) noise that comprises a designed spacer placed between theplunger-biasing spring and the retention spring that guides both the springs and also prevents direct hitting of plunger with the housing while setting back inside the housing. The retention spring is adapted to provide cushioning to the plunger. Therefore, the present tensioner is adapted for preventing metal-metal collision. In an aspect of the present invention, the spacer can be of any polymer. It is yet an object of the present invention to provide a tensioner that comprises a roller which allows the plunger to set back inside the housing to reduce the load over chain in specific conditions.

It is still an object of the present invention to provide a tensioner capable of fulfilling high load requirements.

BRIEF DESCRIPTION OF DRAWINGS

The detailed description is described with reference to the accompanying figure.

FIG. 1 represents a tensioner in accordance with an embodiment of the present invention; FIG. 2 represents a spacer incorporated in the tensioner in accordance with an embodiment of the present invention;

FIG. 3 represents different spacer designs (A-F) in accordance with other embodiments of the present invention;

FIG. 4 represents different spacer designs (G-L) in accordance with other embodiments of the present invention, and

FIG. 5 represents load graph of conventional tensioner 5Aand as present tensioner 5B known in prior art.

DETAILED DESCRIPTION OF EMBODIMENTS As depicted in FIG. 1, a tensioner 100 is disclosed. The tensioner 100 includes a housing 102and a plunger 106. The housing 102 includes a hole for accommodating plunger 106. The hole is having an opening 102(o)and a bottom 102(b) spaced from the opening 102(o). The plunger 106 is arranged to slide and protrude from the opening 120(o) of hole for accommodating plunger 106.

In an embodiment of the present invention, a roller 104 is arranged to support the sliding motion of plunger 106. The roller 104 acts as a guide the plunger for supporting and controlling the drive of the plunger 106. In this embodiment, the plunger 106 is not having teeth therefore can be projected out in forward direction to impart load and can be setback inside to reduce the load over the chain. The plunger 106 without teeth enables the tensioner to provide continuous load to the chain. The tensioner 100 includes a plunger-biasing spring 108, accommodated inside the holebeneath the plunger 106. The plunger-biasing spring 108 operates against the part of the plunger and biases the plunger 106 in the protruding direction. The tensioner 100 further includes a retentionspring 1 10. The retentionspring 110 is preferably of greater spring strength in comparison with the plunger-biasing spring 108.

When the plunger-biasing spring 108 operates, theretentionspring 1 10 supplements the force exerted on the plunger by plunger-biasing spring 108. Subsequently, both springs 108 and 1 10 contribute additively to the total force exalting the plunger 106 in the protruding direction. Therefore, the tensioner is capable of achieving high load characteristics.

The major advantages are provided by configuring a spacer 112 in between the plunger-biasing spring 108 and retention spring 110. The spacer 112 can be of any polymer.

In an embodiment of the present invention as depicted in FIG. 2,the spacer 1 12 includes a disk 1 12d in between an upper shaft 1 12a and a lower shaft 1 12b. The plunger-biasing spring 108 sits over the upper shaft 1 12a and the retention spring 1 10 sits over the lower shaft 1 12b. The spacer 1 12 is designed to support and maintain gap between two springs to avoid bucking and entangling. The spacer 112 is snugly fit inside the housing 102 and fluctuates along the length of housing 102. The spacer also prevents the free movement of retention spring when the plunger 106 is protruded outside the housing.

This arrangement of retention spring 1 10 facilitates cushioning between the plungertherefore preventing the metal-metal interaction and inturn eliminating the noise issue.

In further embodiments of the present invention as depicted in FIG. 3, the spacer 1 12 is designed to have any of shapes (A-F) as shown. The spacer 112 fulfils the primary purpose of prevention of matting metal to metal contact of both springs. Further, the spacer 1 12 is configured in a way to that the plunger 106 to rest on the disk 1 12d.The plunger-biasing spring 108 sits over the upper shaft 1 12a and the retentionspring 110 sits over the upper shaft 1 12b, the spacer 1 12 also support the even retraction of plunger 106 by guidingthe retentionspring 110 by the way of even force retention.

In other embodiments of the present invention as depicted in FIG. 4, the spacer 1 12 is designed to have any of the shapes (G-L) as shown. As shown in FIG. 4 in some embodiments, the spacer 112 is of disk shape which includes a disk 1 12d and optionally includes any or both of an upper shaft 1 12a anda lower shaft 1 12b. The spacer 112 is configured to prevent matting of the plunger-biasing spring 108with the retentionspring 110. Referring to FIG. 1 and FIG. 3, the tensioner lOOmay include a lever 1 14 to retract the plunger 106. The lever 114 can be a metal clip having two arms fixed on the surface of housing 102. The lever 1 14 is arranged to swivel over to lock the plunger 106.

Referring to FIG. 5, the tensioner 100 is capable of giving continuous load (as shown in load graph 5B) to the chain drive because it has smooth set out and set in of plunger 106 in the housing 102. Hence, the present invention eliminates the problem of jerk available in prior art (as shown in load graph 5 A). Some or more aforementioned advantages are incurred by using dual springs such as the plunger-biasing spring 108 and the retention spring 110 for providing higher load to the chain. The further advantages are provided by the spacer 1 12 installed in between the plunger-biasing spring 108 and the retention spring 110 for guiding and preventing the buckling of both the springs.

The disclosure offers an understanding and appreciation for the inventive principles and advantages thereof, rather than to limit in any manner the invention.The invention is defined solely by the claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.