Summary of Invention:
We claim that the present invention relates to Seat Recliners, which are mainly used in the
Seats of Automobiles. Seat Recliner is a mechanism which allows the driver and co-driver to
adjust the position of seating system, by positioning of Seat Back (Angular Adjustment) with
respect to Seat Cushion. The present invention provides the reclining devices in Seating
System by providing lesser consumption of materials, low cost, compact size & lesser weight
designing solution with increase in the static strength of reclining device. At present, there are
many type of reclining devices being used in Automobiles which are solving different
purpose and utility.
In order to accomplish the aforesaid invention and other objects related to it, a Rotary Cam
Type Recliner has been developed which comprises of a Recliner Heart Assembly which is
connected to Seat Cushion and Back. Heart includes an outer disc to be fixed to a seat
cushion through a bracket, and an inner disc (with teeth) to be fixed to Seat Back. The outer
disc encloses sectors (3 No's) and unique inner profiles of outer disc guide the sector
movement for locking, unlocking and accommodating sectors. The inner disc has gear teeth
portion on its inner periphery for engagement with sectors. Sector profile has teeth portion for
engagement with inner disc teeth for locking and unique designed cam profile for facilitating
proper locking through Cam. The locking and unlocking of sectors is initiated by Cam
rotation. Locking happens by the engagement of sector teeth with inner disc teeth where
sectors are moved (radially or straight) through rotation of cam. The Cam surface is directly
in contact with the sector while locking. The unlocking happens again by rotation of Cam in
opposite direction which moves the sectors straight towards center through direct contact
without unlocking plate. The cam is moving through the attachment of shaft and lever. Cam
is always loaded by torque which is applied through recliner locking spring.
Existing State of the Art:
The present disclosure is for the field of seating technology and more particularly for the field
of recliner mechanisms for adjusting the position of a seat back with respect to seat cushion.
Generally, two main types of recliner mechanisms are well known for use in automotive
vehicle seats. First is the well-known pawl and sector recliner mechanism which commonly
uses a pivoted pawl connected to or formed in one structure (such as a seat base frame) and a
toothed gear sector connected to or formed in another structure (such as a seat back frame). It
is also common to have the pawl and sector incorporated in a separate recliner mechanism
that interconnects the seat back frame and the seat base frame.
Second is also a well-known round or rotary recliner mechanism. Most of the known rotary
recliner mechanisms utilize a cam mechanism and movable sectors commonly having teeth.
It is also well known to include a biasing member, typically in the form of a spring, or
multiples thereof, for biasing the lock members in a locked position. Commonly, an actuator,
such as a handle, is used to actuate the cam mechanism to move the lock members, against
the force of the biasing member, to an unlocked position where the teeth of the lock member
are disengaged with mating teeth on either of the side plates of the rotary recliner
mechanism.
Drawbacks in existing State of the Art
Following is the list of drawbacks being considered for the existing designs:
• In existing designs with straight (Non radial) sector movement for unlocking the
recliners, extra unlocking plate (or extra part(s)) is used between sector and cam for
sliding the sectors. Cam is not in direct contact with sector for unlocking the recliner
and that is why, extra component is required for unlocking the recliner.
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- • Some recliners which are available at present recognize the need of improvement in
mechanical strength; in that case they just increased the thickness of the various
components to increase the mechanical strength of reclining device, as well as
unnecessary use of high strength steel thereby increasing the manufacturing cost.
• Also in some of the designs, extra numbers of springs are being used, each for the
separate sector. This increases the complication in design & manufacturing.
• In other design, the numbers of meshing teeth with the internal gears are very less due
to which they have normally lesser strength. In order to improve the mechanical
strength, they normally use multiple mechanisms.
• If we look at the other designs, they normally have one point contact of cam profile
with the sector profile at the time of locking of the reclining mechanism. This induces
lesser stability of locking due to twisting of sector and improper teeth meshing at load
condition ultimately resulting in compromise with static strength.
• In existing designs, heat treatment is done for components to increase static strength.
Accordingly, there is need for a seat back recliner having a relatively simple and
compact design, which also provides seat system enough locking strength with lower
manufacturing cost.
Problem(s) or difficulties which the Invention overcomes
The disadvantage of the prior art may be overcome by providing a uniquely designed
"Sector-Cam Arrangement", having a two point direct contact during locking
conditions.
Following are the ways which we adopted to overcome the difficulties.
Utility of Invention i.e. possible application area(s) of Invention
The Recliner device is mainly used in Automobile Seating System. Need for better solution,
by reducing the cost and weight of product remains the first and foremost priority in the
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Automobile Sector. Thus main focus of this invention is to provide a more reliable &
affordable product solution for the Automobile Seating System.
Objectives of the Invention
The main objective of this invention is to provide an improved Rotary-Cam Type Reclining
Device which has a very uniquely designed sector, cam & outer disc arrangement. It
ultimately increases the static strength in locked condition. Also it provides longer life
periods, require less maintenance, ease of assembly, having compact in size & all this
advantage comes under lower manufacturing cost.
Also this invention provides a solution for the above discussed issues with the present form
of Reclining Device by reduced number of parts count, weight & number of moving parts.
Detailed description of the Invention
An automotive seat assembly is generally shown at Fig 1. The seat assembly includes a seat
cushion (2) and a seat back (1), where seat back is pivotally mounted to the seat cushion (2)
through recliner. The seat assembly is shown in (Fig. 1) is schematically and may be of any
suitable design and configuration. A recliner heart assembly is generally shown at (20) in Fig
4, for providing a recliner feature for the seat back (1). The recliner assembly (3) of the
subject invention allows the seat back (1) to have angular step wise locking positions, relative
to the seat cushion (2) or dump against the seat cushion (2). The dumping features pivotally
move the seat (back and forward) against the seat cushion (2), with a single turn of recliner
assembly (3). The reclining features of the seat back (2) will be discussed in greater detail
below with reference to the specific operation of the recliner assembly (3). Outer ring (29) is
provided to ensure inner disc (14) packaging with outer disc (28) allowing only rotational
movement of inner disc (14) with respect to outer disc (28).
Referring to the Fig (4), showing various components of reclining assembly unit. The inner
disc (14) of recliner heart assembly (20) normally attached with seat back frame side member
(17). Other side of recliner heart assembly (20) i.e. Outer disc (28) is firmly fixed to cushion
through base plate (24). Return spring (21) is fitted with recliner heart (20) through return
spring bracket (19) from one end & other side with hook bracket (25) which is again firmly
fixed to seat back (2) frame side member (17). When recliner (3) is unlocked by rotation of
shaft (22), the return spring rotates seat back (1) in forward direction. The recliner spring (26)
rotates shaft to Jock the recliner at desired position.
Recliner heart assembly as shown in Fig (2 & 5), comprises of uniquely designed outer disc
(28), three number of sectors (4) & cam (7) along with inner disc (14) & ring (29). The cam
(7) includes first, second and third profiles & has a central aperture (10) for receiving a cam
shaft (22). A rotary spring (21) is positioned around the cam shaft (21) and engages the inner
disc (14) at one end, and rotary cam (7) at opposite end. All three no. of sectors (5) are
independently pivotally connected to the outer disc (28), each sector (5) is having an outer
toothed portion (4) at an outer edge thereof engage-able with the inner toothed portion of
inner disc (14), and further having a cam contour surface (32 & 33).
A rotary cam (7) having three profiles engage-able with first, second and third sectors (5)
respectively. The cam is having a uniquely designed profile for the sectors (5) to produce
straight centrifugal or centripetal movement to lock (mesh) and unlock (un-mesh) with the
inner disc by a rotary motion of the cam. The operating lever is mechanically linked with
rotary cam (5) for producing rotary motion of cam.
The sectors (5) are mounted within the outer disc (28) portion, of the recliner heart assembly
(20). The sectors (5) each have a toothed surface and are movable between a locked position
and an unlocked position. When the sectors (5) are in the locked position, the teeth of surface
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engages with the teeth of the internal disc (14) to lock the seat back (1) relative to the seat
cushion (2).
Referring to Fig. 10, when the sectors (5) are in unlocked position, the toothed surfaces are
spaced (36) from the teeth of the internal disc to allow the movement of the seat back relative
to the seat cushion.
In this invention, we have provided uniquely designed Sectors (5), cam (7) and outer disc
(14) in a manner to overcome all issue of present form of reclining devices.
In Fig. 2 it shows engagement of unique cam profile (33-32) with uniquely designed sector
profile (6-13). The designing of both these profile is done in a manner, so that it will
overcome the issue of strength requirement at locking condition by having two point contacts.
Also no. of teeth (4) in sector profile is kept more to improve the static strength.
On the inner side of uniquely designed outer disc (28) we provided a guiding way (27) to
accommodate three sectors with more number of teeth to have better strength.
Fig (8), Refers to the recliner device in lock position & having a two point contact, the
special design provides strength at locked position by preventing twisting of sectors in loaded
condition. It also distributes the load on cam profile, which consequently improves the life of
cam.
Referring to Fig (9), after providing rotational movement to cam, it touches the sector's
unlocking profile. Further rotational movement (35) of cam moves the sector and unlocking
starts.
During unlocking the sector (5) follows straight centripetal movement as shown in Fig. (9),
after covering approximately 16 (degrees) of radial motion of cam from lock position in full
material condition, the sectors teeth are maximum away from internal teeth disc teeth. This
condition is known as fully unlocked position (36). As shown in Fig. 10.
When lever is released by user, cam restoration (41) in Fig. 11, start taking place. Restoring
of cam takes place by spiral-spring (21) which applies torque to cam (7) & forces recliner
back to initial lock position. This cam restoration again pushes all three sectors (4) by direct
contact & moves sectors in straight Centrifugal path.
Description of Drawings:
The main advantages of the invention can be easily understood by the reference of following
drawings.
Fig (1). is a schematic view of seat incorporating the (compact) recliner assembly.
Fig (2).shows a plan view of interior reclining device, with the sector arm in locked position
Fig (3). shows a plan view of internal disc.
Fig (4). shows an exploded view of rotary-cam type reclining device with outer components.
Fig (5). shows an exploded view of Rotary cam type recliner heart assembly.
Fig (6). shows a perspective view of internal Disc.
Fig (7). shows a view of sector-cam arrangement in locking condition.
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Fig (8). shows a two point direct contact of sector-cam during locking condition.
Fig (9). shows a one point direct contact view of sector-cam, during unlocking.
Fig (lO).shows a view of recliner device in fully unlocked condition.
Fig (11). shows a view in which cam restoring started.

CLAIMS:-
1. The cam profile is uniquely designed such that it is in direct contact with sector
during unlocking thereby eliminating the use of extra unlocking plate (or extra
part(s)). Hence number of parts reduced.
2. The uniquely designed cam locks the sector by providing two points contact which
improves stability during locked and loaded condition hence static strength is more.
This improves the design as compared to a single point contact cam sector recliner
mechanisms.
3. Also we provide more number of teeth to sectors which when mesh with the internal
disc gear, give more static strength in locked condition. By increasing the number of
teeth, we have solved the issue of static strength.
4. The outer diameter of recliner is lesser due to more static strength by providing more
number of teeth, which subsequently reduces weight with respect to other
mechanisms.
5. Only one locking spring is being used in this case to provide essential torque to the
cam. This eliminates the use of extra number of spring requirements as used in other
case.