FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See Section 10; rule 13]
"CAM AND CAM SPRING MECHANISM, PREVENTING CAM SPRING SLIP OUT"
ADVIK HI-TECH PVT. LTD.
an Indian private Limited Company,
Plot No. B-5, Chakan Industrial Area, Phase II,
Village-Vasuli, Tal-Khed,
Dist-Pune, Pin-410501
Email: cie@advik.co.in
The following specification describes the invention.

[001] CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application claims priority from Indian provisional application having application number 202421023832 and filed on 26th day of March, 2024.
FIELD OF INVENTION
[002] The present invention relates, in general, to a tensioner assembly featuring cam
design/shape which avoids cam spring pop out in tensioner assembly for transmission drives, such as a belt drive, a rope drive, or a chain drive.
BACKGROUND OF INVENTION
[003] In existing design of tensioner assembly the cam design/shape may lead to pop
out of cam spring while the tensioner assembly is fitted on to the engine. To overcome this issue the cam design/shape is made such that the cam spring will be align with cam profile, spring angle, spring direction cam profile/shape/ design is helpful to lock the spring positively.
[004] A transmission mechanism may involve a power source and a driven apparatus
or a device. Such transmission mechanisms may include a transmission member, such as a chain, a belt, or a rope, to transmit the power from the power source, such as a rotating shaft to the device and a guide that may support the transmission member during the transmission of power. Further, transmission members need adequate tension in order to reduce loss of power during the transmission, since the tautness of the transmission member is directly proportional to the power transmitted. The positive forward directional tension in the transmission is essential for improving efficiency and performance of the transmission mechanism.
DETAILED DESCRIPTION OF THE INVENTION
[005] During the operation of the transmission mechanism, the transmission member
may transmit large amount of forces. Also, during the transmission, the transmission member may undergo various levels of temperature change. These temperature changes may be due to continuous working of transmission member or may be due to environmental factors. Thereby, factors such as, but not limited to, load and heat on the transmission member may cause the transmission member to elongate and lose their original shape and size. The elongation may result in slack in the transmission mechanism. The slack, if goes unchecked, may cause the transmission member to transmit less force, decreasing the efficiency of the transmission system. The slack may also cause unwanted noise and vibration in the transmission system, affecting the performance of the said system. In order to overcome the problem of slack being

generated in the transmission member, the transmission mechanism may include a guide member that supports the transmission member during the transmission of power. The guide member may also provide tension to the transmission member which may cause the transmission member to taut. Such mechanism to maintain tautness of the transmission member, are commonly termed as tensioners. In one example, a tensioner may be used to exert a force on the guide member to maintain tautness of the transmission member.
[006] Examples of tensioner assembly for exerting a force of the cam are described.
The tensioner assembly of the present subject matter may exert a force on the cam when a slack develops in the transmission member. At the same time, the cam shape/profile is made in such that it will locate/guide the cam spring which will prevent the spring pop out in assembly condition. Hence when the vehicle is in operation condition the spring will be intact with cam profile/shape. The operation of the tensioner assembly is unaffected by the reaction force. In other words, the tensioner may resist change in the slack due to the reaction force by the transmission member. Accordingly, according to an aspect, the tensioner assembly based on the present subject matter may include a unidirectional motion mechanism that may resist a back force exerted by the cam on the tensioner assembly. In one example, the unidirectional motion mechanism may allow a tension adjustor of the tensioner assembly to push and exert the force on the cam and may lock the movement of the tension adjustor when the reaction force is exerted by the cam on the tension adjustor.
[007] The advantages of the present subject matter would be described in greater
detail in conjunction with the following figures. While aspects of tensioning the transmission member can be implemented in any number of different configurations, the embodiments are described in the context of the following device(s) and method(s).
FBRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates a sectional view of assembled tensioner assembly 100, in accordance with one implementation of the present subject matter. The tensioner assembly 100 may include a housing 101 which may house the various components of the tensioner assembly 100. The housing 101 may include a plunger 102 disposed in a cavity of the housing 101. The housing 101 may include a cam 103 that may be mounted pivotably on the housing

101. In one example, the cam 103 may abut a lateral surface of the plunger 102. In one example
of the tensioner assembly 100, the housing 101 may also include cam spring assembly disposed
in the housing 101. The plunger assembly may be operably coupled to the cam 103 to bias the
cam 103 to abut against the lateral surface of the plunger 102. The tensioner assembly 100 may
further include a primary biasing/spring member 105 disposed in the cavity of the housing 101
and coupled to the plunger 102. In one example, the primary biasing/spring member 105 may
lie within the cavity of the plunger 102. Further, the housing 101 may also include cam 103,
the housing 101 and abutting the cam. The housing 101 may also include a mounting pin 104
fixedly mounted inside the cavity of the housing 101. The mounting pin 104 may serve as the
mount for the cam 103 such that the cam 103 when mounted on the mounting pin 104, the cam
103 may pivot about an axis of the mounting pin 104. In one example, the housing 101 may
also comprise of bolt 107 and a bolt pin 108 to be mounted at the bottom of the housing so as
to firmly secure the plunger 102 and the primary spring 105 inside the cavity. The bolt pin 108
may also serve the purpose of aligning the primary spring 105 such that the force exerted by
the primary spring 105 may be linear. Further, the sealing washer 109 may provide tautness to
the locking between the bolt 107 and bolt pin 105.
[008] The design of the cam 103a, 103b, 103c is such that the cam 103 may allow a
unidirectional motion mechanism that may resist a back force exerted by the guide (not shown in Fig. 1) on the tensioner assembly 100. In one example, the cam 103 may be a cam, and in said example, the design of the cam 103 and the cooperation of the cam 103 with other components may be such that the unidirectional motion of the cam 103 may allow the plunger
102 of the tensioner assembly 100 to push and exert the force on the guide and may lock the
movement of the plunger 102 when the reaction force is exerted by the guide on the plunger
102. In one example, the cam 103 may rotate in anti-clockwise direction when the plunger 102
moves out of the body 101 and the cam 103 may rotate in the clockwise direction when the
plunger 102 moves into the body 101. According to an aspect, the shape and design of the cam
103 is such that the cam 103 may allow the exertion of first teeth locking force on the plunger
102 when the tension plunger 102 moves out of the housing 101 upon the application of force
by the primary cam spring member 106. Further, the cam 103 may exert a second positive
locking force on the plunger 102 to lock the tension plunger 102 against moving into the
housing 101 the direction opposite to the transmission member due the reaction force exerted
by the transmission member. In the above stated example, the design of the cam 103 is such
that the design of the cam may allow for the first positive force exerted on the plunger 102 to
be less than the second force exerted on the tensioner plunger 102. Therefore, the cam 103

Part no. Part Name
100 Tensioner Assembly
101 Housing
102 Plunger
103 Cam
103a 103b slot

blind hole
103c dimple hole
104 Cam Pin
105 Plunger Spring
106 Cam Spring
107 Bolt
108 Bolt Pin
109 Washer

LIST OF NUMARALS

CLAIMS
WE CLAIMS
1. A tensioner assembly (100) comprising:
a housing (101) having a cavity;
a tension plunger (102) disposed in the cavity to be linearly movable in the cavity of
housing;
a cam (103) operably engaged with the tension plunger (102) to allow the tension
adjustor (102) to linearly move in the cavity in a first direction upon application of a
force on the tension plunger (102), and to lock the tension plunger (102) to prevent a
linear movement of the tension plunger (102) in a direction opposite to the first
direction.
Wherein the cam spring 106 push the cam 103 having shape of slot (103a), blind hole
(103b), dimple hole (103c) towards the tension plunger 102
Characterized in that:
A cam (103) is pivotably mounted on the housing (101) and abutting a lateral surface of the tension plunger (102), wherein the cam (103) comprises a cam (103) profile to exert and having shape of slot (103a), blind hole (103b), dimple hole (103c) and a first frictional force on the tension plunger (102) when the tension plunger (102) linearly moves in a first direction upon application of a force, and wherein the cam profile is to exert a second frictional force on the tension plunger (102) to lock the tension plunger (102) against moving in a direction opposite to the first direction.
2. The tensioner assembly (100) as claimed in claim 1, comprising an elastic assembly disposed
in the housing 101 and operably coupled to the cam 103, and abut against the cam 103, a cam
spring 106 fixed into the housing 101 and locate in cam profile/shape unique and guides the
cam spring 106 for applying a biasing force of the cam 103, the elastic assembly coupled to the
cam 103 to bias the cam 103 to abut against the toothed surface of the tension plunger 102, the
cam spring 106 push the cam 103 towards the tension plunger 102, and allow the tension
plunger 102 to move out of the housing 101, the tension plunger 102 will not move inside the
housing 101 due to application of teeth engagement reaction forces, cam 103 resist the
movement of the plunger 102 prevents the cam spring (106) pop out in any engine working
condition of tensioner assay (100).