FORM 2
THE PATENT ACT 197
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
1. TITLE OF THE INVENTION
CAP ELEMENT IN TENSIONER
2. APPLICANT
(a NAME: ADVIK HI-TECH PVT LTD
(b)NATIONALITY: Indian Company
Plot No. B-5, Chakan Industrial 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] For a tensioning device for an endless drive element, in particular a timing chain of an internal combustion engine, comprising a tensioning rail which is adapted to be operatively connected to the endless drive element, and a tensioning nut which is supported in a housing in an axially displaceable manner and which presses against the tensioning rail, this object is achieved in that an end face of the tensioning nut is adapted to be connected to a cap element extending beyond the tensioning nut and forming a pressure face which is in engagement with the tensioning rail.
[003] In view of the fact that the end face of the tensioning nut is adapted to be connected to a separate element i.e. a cap element, which is in contact with the tensioning rail, this element, which is subjected to high wear during operation, can simply be replaced without any necessity of exchanging the complete tensioning device. It is also possible to use different materials for the cap element and the tensioning nut so as to achieve special characteristics when the tensioning device is in use.
[004] Also the problem faced with conventional tensioner is that the cap provided does not move according to the slackness of the chain.

DISCLOSURE OF THE INVENTION
[005] 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 screw is tlireadedly 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.
[006] According to the present invention, the tensioner is provided with a cap element made of metal.
[007] According to the present invention, the tensioner provided with a cap element can be made of plastic as well.
[008] The cap element provided is in hemispherical shape. The cap element possesses certain thickness. Cap element is a surface being hollow in the inside. Moreover, the cap element has a hole drilled across in order to allow a pin to pass through. The cap element is secured to the nut by pressing the pin through the hole provided en the cap element and the nut.
[009] It is an object of the present invention to provide a tensioner with a cap element that moves according to the slackness of the chain.
[010] It is an object of the present invention to maintain contact of the nut with the tensioning rail.
[011] It is an object of the present invention to provide an easily replaceable cap element.
[012] It is an object of the present invention to overcome the shortcomings mentioned in the prior art.

BRIEF DESCRIPTION OF DRAWINGS
[013] Fig.l shows a sectional view of the tensioner.
[014] Fig. 2 shows side view of tensioner assembly.
DESCRIPTION OF THE DRAWINGS
[015] Figure 1 shows a tensioner having a body 3, screw 1, nut 2, spring 4, bearing 5, circlip 8, O-ring 10, stopper 11, thrust member 7, cap element 9 and a pin 7. Tensioner illustrated in Figure 1 consists of a screw 1 having external threads engaged with the internal threads formed inside the nut 2. Screw 1 threadedly engaged with the nut 2 is placed in the tensioner body 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 4 translates into linear motion of the nut 2 on account of across flat. 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 and the steps provided on the bearing 5. The cap element 9 provided on the nut is of hemispherical shape though various shapes of the cap element 9 can be formed. The thickness of the hollow hemispherical cap element 9 ranges from 1 mm to 5 mm. The cap element 9 is designed in such a way so as to move according to the slackness of the chain.
[016] Fig. 2 shows side view of tensioner assembly. The figure clearly illustrates movement/tilting of cap element in accordance with the slackness of the chain. The pin 7 passes through the hole drilled on the cap element 9. Cap element 9 is secured tightly to the nut 2 with the help of a pin 7. Cap element 9 is secured to

the nut 2 in such a way that it allows tilting movement of cap element 9 according to the slackness of the chain.

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 case;
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 cap element extending beyond the nut forms a pressure face which is engaged
with the tensioning rail.
2)A tensioner as claimed in Claim 1, wherein the cap element is hemispherical in shape.
3)A tensioner as claimed in Claim 1, wherein the thickness of the cap element ranges from 1 mm to 5 mm.
4)A tensioner as claimed in Claim 1, wherein the cap element is made of metal.
5)A tensioner as claimed in Claim 1, wherein the cap element is made of plastic.