Claims:CLAIMS
We Claim:

1. A self-locking hold device (100) for holding and locking a cover element (10) in open condition against gravity, the cover element being hinged to a chassis (20) of a automotive vehicle at one end, the self-locking hold device (100) comprising:
at least one first arm (30) having one end thereof pivotally connected to the cover element (10);
at least one second arm (40) having one end thereof pivotally connected to the chassis (20);
a pin (50) pivotally connecting the free ends of the first arm (30) and the second arm (40) together;
a plate (32) fixed to the first arm (30) near the pin (50) and configured with a locking hole (36) thereon, position of the locking hole (36) deciding the locking angle of the cover element (10);
a plunger guide (44) fixed on the second arm (40) near the pin (50) for holding a plunger pin (48) therein against the force of a spring (46) coiled thereon, the plunger pin (48) having a locking end (48a) and a control end (48b), a plunger key (42) fixed at the control end (48a) and adapted for holding and releasing the plunger pin (48) on rotation, wherein the locking end (48a) rests on the plate (32) when the cover element (10) is in closed condition; and
an actuator pin (34) provided on the plate (32) and configured for rotating the plunger key (42) during downward movement of the cover element (10);
wherein, during opening of the cover element (10), the locking end (48a) slides on the plate (32) and gets locked into the locking hole (36) thereby locking the cover element (10) in a predefined locking angle;
the locking end (48a) is released from the locking hole(36) by manually pulling and rotating the plunger key (42) against the spring force, thereby holding the plunger pin (48) in the plunger guide (44) and allowing the cover element (10) to move downwards; and
during downward movement of the cover element (10), the plunger key (42) gets rotated by the actuator pin (34), thereby releasing the plunger key (42) from the plunger guide (44) and setting the locking end (48a) to slide and rest on the plate (32).

2. The self-locking hold device (100) as claimed in claim 1, wherein the automotive vehicle is a construction equipment.
3. The self-locking hold device (100) as claimed in claim 1, wherein the cover element (10) is any one selected from a engine bonnet, a engine hood, a door, a frame and a cover operating against gravity.
Dated this 6th day of August, 2018

Ashwini Kelkar
(Agent for Applicant)
IN-PA/2461
, Description:SELF-LOCKING HOLD DEVICE
Field of the invention:
The invention generally relates to a self-locking device for holding a cover/ bonnet / hood in open condition against gravity, and more particularly it relates to a self-locking mechanism in the hold device of a construction equipment to prevent the free fall of lift up door/hood.
Background of the invention:
In construction equipment’s/vehicle a hood, cover or door is provided to access the engine, a cooling system, a hydraulic system and lubrication system for maintenance/ servicing the mechanical elements accommodate under the hood.
Generally, the hood is hinged at one end with chassis of the construction equipment and other end has a provision to open/close and lock the hood. Whenever any of these systems need maintenance or service or access, the hood is opened and held in open condition by any one of a gas spring force, manually actuated support member or both to hold the hood in preset condition for the safe operation.
However, current arrangements of locking the hood at its maximum opening angle with manual lock or retaining with the gas spring force, pose great threat to the service person/operator, as in case of mishandling of manual locking or in case of the gas spring failure of the locking arrangement can injure the service personal.
Further, the above-mentioned mechanism of locking the hood may get unlocked due external disturbances of machine vibration, unintentional unlocking & failure of gas spring and provide a non-safe working zone for the operator.
Accordingly, there exists a need for locking mechanism for hood of the construction equipment which overcomes abovementioned drawbacks.

Objects of the invention:
An object of the present invention is to provide a device for holding and self locking the engine hood/cover in open condition.
Another object of the present invention is to provide a self-enabled open position hold device for the hood, which can restrict the external disturbances due to machine vibration.
Summary of the invention:
Accordingly, the present invention provides a self-locking hold device for locking a hood/ bonnet/ cover/ frame in open condition that is opened against gravity. Specifically, the self-locking hold device of present invention is installed in a construction equipment or automotive vehicle, wherein the engine cover element (hood) needs to be locked in open condition for accessing the inner parts like engine, cooling system, hydraulic system, lubrication system, etc for maintenance/ access/ servicing of the mechanical elements. The cover element is hinged to the vehicle chassis at one end. The self-locking hold device comprises of two arms. A first arm is pivotally connected to the cover element, second arm is pivotally connected to chassis, while their free ends pivotally pinned together. A plate configured with a locking hole and a actuator pin is attached to the first arm near the pin joint. A plunger guide housing a plunger pin connected with a plunger key for holding the plunger pin under a spring force, is installed on the second arm near the pin joint. The plunger pin is having a locking end and a control end. The plunger key is rotated in clockwise or anticlockwise direction for holding or releasing the plunger pin in or out of the plunger guide. When the cover element is in closed position, the locking end of the plunger pin is resting on the plate. During opening of the cover element, the locking end slides on the plate and gets locked in the locking hole at a predefined angle. Position of the hole on the plate decides the locking angle. For closing the cover element, the plunger pin first unlocked by manually pulling it out of the locking hole to rest in the plunger guide. This is done by pulling and rotating the plunger key. During closing of the door, the actuator pin pushes the plunger key to rotate, thereby releasing the plunger pin out of the plunger guide and rest on the plate again.
Brief description of the drawings:
The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
figure 1 shows an isomeric view of the self-locking hold device fixed on a automotive vehicle, in accordance with the present invention;
figure 2a shows a detailed view of the self-locking hold device, in accordance with the present invention;
figure 2b shows a second arm of the self-locking hold device, in accordance with the present invention;
figure 2c shows a first arm of the self-locking hold device, in accordance with the present invention;
figure 3a shows a side view of the vehicle hood and chassis fitted with the self-locking hold device, locked at predefined angle in open condition, in accordance with the present invention;
figure 3b shows a detailed view of section A-A of the self-locking hold device shown in figure 3a, in accordance with the present invention;
figure 4a shows a side view of the vehicle hood and chassis fitted with the self-locking hold device, in disengaged condition of the lock, in accordance with the present invention;
figure 4b shows a detailed view of section B-B of the self-locking hold device shown in figure 4a, in accordance with the present invention; and
figure 5 shows a side view of the vehicle hood and chassis fitted with the self-locking hold device, in closed condition of the lock, in accordance with the present invention.
Detailed description of the embodiments:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
The present invention provides a self-locking hold device for locking and holding a cover element in open condition that is opened against gravity. In a specific embodiment, the cover element is a hood/ bonnet/ cover/ frame hinged to the vehicle chassis at one end. The self-locking hold device comprises of two arms, each pivotally connected to the cover element and the chassis, while their free ends are pivotally pinned together. A locking arrangement is provided near the pin joint which enables to hold and self-lock the cover element in open condition at a predefined angle. The locking arrangement is a novel self locking cam and plunger arrangement with linkage mechanism.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description. Table 1 below enlists all the reference numerals along with respective component names:
Table 1
Ref No Component Ref No. Component
10 Cover element 42 Plunger key
20 Chassis/vehicle body 44 Plunger guide
30 First arm 46 Spring
32 Plate 48 Plunger pin
34 Actuator pin 48a Locking end of plunger pin
36 Locking hole 48b Control end of plunger pin
40 Second arm 50 Pin

Referring to figures 1 to 5, a self-locking hold device (100) for locking a cover element (10) in open condition against gravity is disclosed. In an embodiment, the automotive vehicle is a construction equipment and the cover element (10) is a engine hood, bonnet, door, frame or a cover operating against gravity. The cover element (10) is hinged with a chassis (20) of the automotive vehicle at one end and having provision to open from other end. The self-locking hold device (100) for safely locking and holding the cover element (10) in open condition at a predefined angle comprises of a first arm (30) pivotally connected to the cover element (10) at one end thereof, a second arm (40) pivotally connected to the chassis (20) at one end thereof, a pin (50) pivotally connecting the free ends of the first arm (30) and the second arm (40) together and a locking arrangement configured on the first arm (30) and the second arm (40).
A plate (32) is fixed to the first arm (30) near the pin (50) and configured with a locking hole (36) thereon. Position of the locking hole (36) decides the locking angle of the cover element (10).
A plunger guide (44) is fixed on the second arm (40) near the pin (50) for holding a plunger pin (48) therein against the force of a spring (46) coiled on the plunger pin (48). The plunger pin (48) is having a locking end (48a) and a control end (48b). The control end (48b) is attached with a plunger key (42) adapted for holding and releasing the plunger pin (48) on rotation. The locking end (48a) rests on the plate (32) when the cover element (10) is in closed condition, it slides on the plate (32) during upward motion of the cover element (10) and gets locked into the locking hole (36) when the predefined angle is reached in open hood condition. The locking end (48a) is released from the locking hole (36) by manually pulling it with the plunger key and rotating the plunger key (42) against the spring force. This brings the plunger pin (48) to resting position inside the plunger guide (44) thereby allowing the cover element (10) to move downwards.
An actuator pin (34) is also provided on the plate (32) which is configured for rotating the plunger key (42) during downward movement of the cover element (10). During downward movement of the cover element (10), the plunger key (42) gets rotated by the actuator pin (34), thereby releasing the plunger key (42) from the plunger guide (44) and setting the locking end (48a) to slide and rest on the plate (32).
Advantages of the invention:
• The self-locking hold device (100) of the present invention holds the opened cover element automatically in locked condition.
• It prevents the unintentional disengaging of hold device.
• It prevent a person from opening the door/cover/hood/system above the recommended opening angle
• The self-locking hold device (100) can be adapted to any such retaining requirements in the construction equipment.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.