FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: CAM MECHANISM FOR PREVENTING BACKWARD
MOVEMENT OF PLUNGER
2. Applicant(s)
NAME NATIONALITY ADDRESS
ADVIK HI-TECH PVT LTD Indian Plot No. B-5, Chakan Industrial
Area, Phase II, Village-Vasuli, Taluka-Khed, District-Pune, Maharashtra 410501, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[001] The present invention relates, in general, to a tensioner assembly for transmission
drives, such as a belt drive, a rope drive, or a chain drive.
BACKGROUND
[002] 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 and hence affects the efficiency and performance of the transmission mechanism.
BRIEF DESCRIPTION OF DRAWINGS
[003] The detailed description is described with reference to the accompanying figures.
In the figures, the left-most digit(s) of a reference number identifies the figure in which the
reference number first appears. The same numbers are used throughout the drawings to reference
like features and components.
[004] Fig. 1 illustrates a sectional view of assembled tensioner assembly, in accordance
with one implementation of the present subject matter.
DETAILED DESCRIPTION
[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] Generally, the tensioners include a tension adjustor biased by a biasing member
such that the tension adjustor may contact the guide towards the transmission member. This causes the guide to exert force on the transmission member. As the transmission member begins to slack, the biasing member causes the tension adjustor to exert the force to the guide, making the transmission member to go taut. Further, the transmission member may also exert a reaction force on the guide, thereby cancelling the force exerted by the tensioner. This may also cause the tension adjustor to move in the direction opposite to the transmission member, causing the tensioner to lose force on the guide member and eventually on the transmission member.
[007] Conventional tensioners may comprise of tension adjustor with teeth or serrations
in contact with a roller having same teeth or serrations. In order to provide tension to the transmitting member, the roller is set to lock so that the tension adjustor may remain in the required place. The circular profile of the roller allows the movement of the tension adjustor in the backward direction also, causing the tension adjustor to exhibit bidirectional motion. The bidirectional motion leads to uneven taut of the transmission member. The conventional tensioner may also require skilled labor for its assembly. This may lead to the training of the labor for the tensioner assembly. Also, the cost involved in the manufacturing the tension adjustor and the roller with teeth or serrations may be comparatively high. The teeth or serrations may also lead to high wear and tear due to high forces involved in the transmission mechanism. The conventional tensioners may also lead to failure because of the breakage of the teeth or the serrations.
[008] Examples of tensioner assembly for exerting a force on the guide are described.
The tensioner assembly of the present subject matter may exert a force on the guide when a slack develops in the transmission member. At the same time, 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, the tensioner assembly based on the present subject matter may include a unidirectional motion mechanism that may resist a back

force exerted by the guide 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 guide and may lock the movement of the tension adjustor when the reaction force is exerted by the guide on the tension adjustor.
[009] The tensioner assembly may include a tension adjustor and a regulator housed
inside a housing of the tensioner. The tension adjustor is disposed in the cavity of the housing which may move linearly in the cavity. The regulator may be pivotably mounted on the housing and abuts a lateral surface of the tension adjustor. The regulator may allow the exertion of a frictional force on the tension adjustor to lock the tension adjustor against moving in the opposite direction occuring due the reactional force exerted by the transmission member. The tensioner may include an elastic assembly disposed in the housing and operably coupled to the regulator. The elastic assembly may bias the regulator in a direction such that it is aligned with the outward linear motion of the tension adjustor.
[0010] 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).
[0011] 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 tension adjustor 102 disposed in a cavity of the housing 101. The housing 101 may include a regulator 103 that may be mounted pivotably on the housing 101. In one example, the regulator 103 may abut a lateral surface of the tension adjustor 102. In one example of the tensioner assembly 100, the housing 101 may also include an elastic assembly disposed in the housing 101. The elastic assembly may be operably coupled to the regulator 103 to bias the regulator 103 making the regulator 103 to abut against the lateral surface of the tension adjustor 102. The tensioner assembly 100 may further include a primary biasing member 109 disposed in the cavity of the housing 101 and coupled to the tension adjustor 102. In one example, the primary biasing member 109 may lie within the cavity of the tension adjustor 102. Further, the housing 101 may also include a cam stopper 104 that may be fixedly mounted to the housing 101 and abutting the regulator 103 such that the cam stopper 104 abuts the regulator 103 at one end.

The housing 101 may also include a mounting pin 105 fixedly mounted inside the cavity of the
housing 101. The mounting pin 105 may serve as the mount for the regulator 103 such that the
regulator 103 when mounted on the mounting pin 105, the regulator 103 may pivot about an axis
of the mounting pin 105. In one example, the housing 101 may also comprise of bolt 111 and a
bolt pin 110 to be mounted at the bottom of the housing so as to firmly secure the tension regulator
102 and the primary biasing member 109 inside the cavity. The bolt pin 110 may also serve the
purpose of aligning the primary biasing member 109 such that the force exerted by the primary
biasing member 109 may be linear. Further, the sealing ring 112 may provide tautness to the
locking between the bolt 111 and bolt pin 112.
[0012] The design of the regulator 103 is such that the regulator 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 regulator 103 may be a cam, and in said example, the design of the regulator 103 and the cooperation of the regulator 103 with other components may be such that the unidirectional motion of the regulator 103 may allow the tension adjustor 102 of the tensioner assembly 100 to push and exert the force on the guide and may lock the movement of the tension adjustor 102 when the reaction force is exerted by the guide on the tension adjustor 102. In one example, the regulator 103 may rotate in anti-clockwise direction when the tension adjustor 102 moves out of the housing 101 and the regulator 103 may rotate in the clockwise direction when the tension adjustor 102 moves into the housing 101. According to an aspect, the shape and design of the regulator 103 is such that the regulator 103 may allow the exertion of first frictional force on the tension adjustor 102 when the tension adjustor 102 moves out of the housing 101 upon the application of force by the primary biasing member 109. Further, the regulator 103 may exert a second frictional force on the tension adjustor 102 to lock the tension adjustor 102 against moving into the housing 101 in the second direction opposite to the transmission member due the reaction force exerted by the transmission member. In the above stated example, the design of the regulator 103 is such that the design of the cam may allow for the first frictional force exerted on the tensioner adjustor 102 to be less than the second frictional force exerted on the tensioner adjustor 102. Therefore, the regulator 103 may be prevented from rotating in the opposite direction, thereby locking the tension adjustor 102 from moving inside the housing 101. In one example, the locking mechanism is enabled by the shape of the regulator 103,

since the design of the regulator 103 may allow the tension adjustor 102 to exhibit unidirectional motion.
[0013] In an example, the tension adjustor 102 may be disposed in the cavity of the housing
101 such that the tension adjustor 102 is linearly movable in the cavity. The tension adjustor 102 is biased by a primary biasing member 109 such that the tension adjustor 102 protrudes partially out of the housing 101.Further, the tension adjustor 102 may protrude out in the direction of the transmission member. Since, the tension adjustor 102 moves linearly, the regulator 103 may abut with the lateral surface of the tension adjustor 102 so as to complement the linear motion exhibited by the tension adjustor 102.
[0014] According to an example, the tensioner assembly 100 may comprise of an elastic
assembly disposed in the housing 101 and operably coupled to the regulator 103. In an example, the elastic assembly may comprise of a ball 108 to abut against the regulator 103, a biasing member
107 coupled to the ball 108 and a grub screw 106 for applying a biasing force of the regulator 103. The elastic assembly may be coupled to the regulator 103 to bias the regulator 103 to abut against the lateral surface of the tension adjustor 102. Further, the elastic assembly may facilitate the rotation of the regulator 103 in one direction but may prevent the rotation in other direction. For instance, the ball spring 107 and ball 108 may push the regulator 103 towards the tension adjustor 102, and thus may allow the tension adjustor 102 to move out of the housing 101. Also, when the tension adjustor 102 moves inside the housing 101 due to application of reaction forces, the ball
108 and ball spring 107 exerts a force of the regulator 103 to resist the movement of the tension adjustor 102. In one example, the biasing force of the ball spring 107 then acts on the regulator 103 causing generation of frictional force between the regulator 103 and the tension adjustor 102 that resist the movement of the tension adjustor 102. The regulator 103 may allow the tension adjustor 102 of the tensioner assembly 100 to push and exert the force on the guide and may lock the movement of the tension adjustor 102 when the reaction force is exerted by the guide on the tension adjustor 102.
[0015] The present subject matter allows for a tensioner assembly 100 to have a
mechanism which may allow unidirectional movement of the tension adjustor 102. The said mechanism may also ensure that force exerted by the primary biasing member 109 is also maintained. In alternate example, the regulator can be implemented as gears, ratchet mechanism, rack and pinion or the like. The present subject matter may allow for lesser number of parts, the

assembly of the tensioner would not require skilled labour, and eliminating the expenses occurred
in the training of the work force for assembly. Also, the shape of the regulator 103 needs to be
precise for the present invention, machining the regulator 103 may lead to tolerance in the
dimensions. Sintering allows for reduced manufacturing cost and high quality of regulator with
accurate dimensions. In one example, the tension adjustor 102 may be manufactured using
sintering, which is economical than other manufacturing techniques. Also, for a certain amount of
force, the size of the tensioner in the presented subject matter can be relatively small when
compared to the conventional tensioners because the tensioner assembly 100 needs lesser number
of parts and the frictional forces between the tension adjustor 102 and the regulator 103 allow for
high endurance during force exertion. Therefore, the shape and size of the tensioners can be
reduced and can be used in all sizes of tensioners.
[0016] Various modifications of the disclosed embodiments, as well as alternate
embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the scope of the present subject matter as defined.

I/We Claim:
1. A tensioner assembly (100) comprising:
a housing (101) having a cavity;
a tension adjustor (102) disposed in the cavity to be linearly movable in the cavity; and
a cam (103) pivotably mounted on the housing (101) and abutting a lateral surface of the tension adjustor (102), wherein the cam (103) comprises a cam profile to exert a first frictional force on the tension adjustor (102) when the tension adjustor (102) exhibits a linear motion in a first direction upon application of a force, and wherein the cam profile is to exert a second frictional force on the tension adjustor (102) to lock the tension adjustor (102) against moving in a direction opposite to the first direction.
2. The tensioner assembly (100) as claimed in claim 1, further comprising an elastic assembly disposed in the housing (101) and operably coupled to the cam (103) to bias the cam (103) to abut against the lateral surface of the tension adjustor (102), wherein a biasing force on the cam (103) by a biasing member (107) of the elastic assembly is in a direction aligned with the first direction.
3. The tensioner assembly (100) as claimed in claim 2, wherein the elastic assembly comprises:
a ball (108) to abut against the cam (103);
a biasing member (107) coupled to the ball (108) to apply the biasing force on the cam (103) through the ball (108); and
a grub screw (106) to adjust the biasing force by the biasing member on the cam (103).
4. The tensioner assembly (100) as claimed in claim 1, further comprising a primary biasing member (109) disposed in the cavity and coupled to the tension adjustor (102) to apply the force on the tension adjustor (102) to linearly move the tension adjustor (102) in the first direction.
5. The tensioner assembly (100) as claimed in claim 1, further comprising a cam stopper (104) fixedly mounted to the housing (101) and abutting the cam (103) to arrest motion of the cam (103) for applying the first frictional force on the tension adjustor (102).
6. A tensioner assembly (100) comprising:

a housing (101) having a cavity;
a tension adjustor (102) disposed in the cavity to be linearly movable in the cavity; and
a regulator (103) operably engaged with the tension adjustor (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 adjustor (102), and to lock the tension adjustor (102) to prevent a linear movement of the tension adjustor (102) in a direction opposite to the first direction.
7. The tensioner assembly (100) as claimed in claim 6, wherein the regulator (103) is a cam (103) pivotably mounted on the housing (101) and abutting a lateral surface of the tension adjustor (102), wherein the cam (103) comprises a cam (103) profile to exert a first frictional force on the tension adjustor (102) when the tension adjustor (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 adjustor (102) to lock the tension adjustor (102) against moving in a direction opposite to the first direction.
8. The tensioner assembly (100) as claimed in claim 7, further comprising an elastic assembly disposed in the housing (101) and operably coupled to the regulator (103) to bias the regulator (103) to abut against the lateral surface of the tension adjustor (102), wherein a biasing force on the regulator (103) by a biasing member (107) of the elastic assembly is in the direction aligned with the first direction.
9. The tensioner assembly (100) as claimed in claim 7, further comprising a stopper (105) fixedly mounted to the housing (101) and abutting the regulator (103) to arrest motion of the regulator (103) for applying the first frictional force on the tension adjustor (102).
10. The tensioner assembly (100) as claimed in claim 6, further comprising a primary biasing member (109) disposed in the cavity and coupled to the tension adjustor (102) to apply the first force on the tension adjustor (102) to linearly move the tension adjustor (102) in the first direction.