FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
1. TITLE OFTHE INVENTION
iFLATNESS OF TENSIONER BODY

2. APPLICANT

(a) NAME:ADVIK HI-TECH PVT LTD
(b) NATIONALITY: Indian Company

i
| Plot No. B-5. Chakan Industnal Area.
| (c) ADDRESS: '
Phase II. Village Vasuli. Taluka Khed.
District Pune. Pin Code-410501.State
Maharashtra. Country India.

TECHNICAL FIELD
[001] The present invention relates to a tensioner that imparts a predetermined tensile force to a force transmitting member such as a chain or timing belt that drives a camshaft of an engine mounted in a vehicle for e.g. four wheeler automobile or a two wheeled vehicle.
BACKGROUND ART
[002] Tensioner is fitted on the engine to provide tension to the cam chain. By providing sufficient tension, the cam chain tensioner ensures accurate opening and closing timings of the inlet and exhaust valves of the engine. Tensioner is secured lo the engine with the aid of nut and bolt. Half portion of the tensioner is exposed to the inside of the engine while rest half extends outside the surface of the engine. The portion of the tensioner inside the engine is always exposed to oil being splashed by the lubrication system of the engine.
[003] Hence, there is probability that the oil splashed by the lubrication system may leak outside the engine via the gap between the flange of the tensioner and the contact surface where the tensioner is mounted on the engine.
[004 i Leakage of oil from the engine will lead to reduced oil levels which in turn may severely affect the functioning of the engine.
[005] As the leakage of oil is undesirable, it is necessary to counter the problem.
DISCLOSURE OF THE INVENTION
[006] According to the present invention, the tensioner comprises a body', screw. nut. spring, bearing, stopper. O-ring. circlip and a cap element fitted on the nut. The screw7 is threadedly engaged with the nut. Screw and nut are placed in the body. Screw has a slit in its head in which one end of the spring is inserted. Another end of the spring is inserted in the slot provided in the body. Body has an opening at one end to allow projection of the nut when the screw is energized by the spring. Body has slots in the bottom to engage stopper.

[007] According to the present invention, the engine mounting face of the tensioner body is provided with a flatness of less than 0.1 millimeter (100 microns)
[008] It is an object of the present invention to provide a tensioner body that eliminates leakage.
[009] It is an object of the present invention to provide a tensioner body which seals the gap between the flange of the tensioner and the contact surface where the tensioner is mounted on the en sine.
[010] It is an object of the present invention to overcome the problems associated with the prior art.
BRIEF DESCRIPTION OF DRAWINGS
[011] Fig.l shows a sectional view of the tensioner.
[012] Fig. 2 shows top view of the tensioner.
DESCRIPTION OF THE DRAWINGS
[013] Figure 1 shows a tensioner having a body 3. screw 1. nut 2. spring 4, bearing 5, circiip 8.. O-ring 10, stopper 11. cap element 9, thrust member 6 and a pin 7. Tensioner illustrated in Figure 3 consists of a screw 1 having externa] threads engaged with the internal threads formed inside the nut 2. Screw 1 threadedly engaged with the nut 2 is placed in the tensioner bod)' 3. Tensioner body 3 has an opening at the top to allow the nut 2 to project outside from the body 3 while the body 3 has slots at the bottom to engage stopper 11 in the body 3 and the screw 1 One end of the spring 4 is engaged in the slit provided in the body 3 while other end is hooked in the slot provided in the body 3. The rotary motion of the screw 1 on being energized by the spring translates into linear motion of the nut 2 on account of across fiat. Stopper 11 provided is used to energize the spring 4 and prevent the screw 1 from rotating. O-ring 10 provided

fits in the groove provided on the body 3. Bearing 5 provided has steps that fit into the slots provided at the top of body 3. Bearing 5 is secured to the body 3 by-means of circlip 8 that passes through the groove provided on the body 3 and the steps provided on the bearing' 5.
[014] Figure 2 shows top view of the tensioner. Tensioner surface 12 or contact surface 12 of the body that contacts with the engine outer surface is marked in the diagram. The flatness of the tensioner surface provided is less than 0.1 millimeter (100 microns) By providing a flatness of less than 0.1 millimeter (100 microns), the gap between the flange of the tensioner and the outer surface of the engine is sealed. Sealing of the gap ensures that there is no leakage of oil from the inside of the engine.

CLAIMS
1) A tensioner that converts a rotary force of the screw into an impulsive force in an
axis line direction of a nut, the tensioner comprising:
a body;
screw being rotatably received in the case in such a state that movement thereof in
the axis line direction is caused to be restrained;
the nut being threadedly engaged with the screw, said nut being movable in the
axis line direction, and rotation thereof with respect to the case being caused to be
restrained, and on said nut a load from a force transmitting member is adapted to
act in the axis line direction;
a spring being stored in an inner portion of the case, which imparts the rotary
force to the screw; and
the cap element that moves according to the slackness of the tensioning rail.
characterized in that:
the contact surface of the case contacting the engine surface seals the gap between
contact surface of the case and the engine surface.
2) A tensioner as claimed in Claim 1, wherein the contact surface of the body has a
flatness of less than 0.1 millimeter.(100 microns)