SAFETY DEVICE FORMING PART OF A MECHANISM FOR LOCKING A MOTOR VEHICLE HOOD AGAINST OPENING

Abstract: The safety device comprises a flat spring (10) which has an end provided with an operating push button (12) and which is arranged to engage a hook (5) of the swinging hood to prevent the hood ope­ ning after it has undergone a predetermined swinging movement following its release, the hook being provided with an active edge (19,20,21) arranged to cooperate with the spring and having a profile such as to flexurally deform said spring.

Description: This invention relates to a safety device forming part of a mechanism for locking a swinging hood, in particular a motor vehicle engine hood, against opening. Said mechanisms are known to comprise release means which release a hook rigid with the hood to allow it to open, and a safety device the purpose of which is to prevent the hood opening after it has swung through a predetermined distance following its release. The hood is able to undergo the further swinging movement required for it to move into its completely open state only after a predetermined force has been exerted on an operating pushbutton with which the said safety device is provided. These safety devices normally comprise a flat spring arranged to engage the hook provided on the hood after this latter has undergone the initial said swinging movement, which takes place following release of the hood. This flat spring has a first end fixed to a plate rigid with the vehicle body and its second end provided with the said operating pushbutton. The spring is flexurally deformable, by pressing the pushbutton, from a first deformed configuration in which the spring is hooked by the hook on termination of the initial predetermined swinging movement of the hood so as to form a safety means to prevent the hood opening, to a second deformed configuration in which the spring is released from the hook to allow complete opening of the hood. Safety devices of the indicated type, which form part of the hood locking mechanism, have the drawback that when said spring is engaged by the hook to prevent opening of the hood, the operating pushbutton fixed to the end of the spring is not visible from the outside of the motor vehicle, as it is covered by the hood and is accessible only through the narrow space which is left free between this latter and the vehicle body. Consequently, in order to gain access to the safety device and operate the operating pushbutton of the device, several blind attempts have to be made to locate said pushbutton. This operation is uncomfortable, in particular when carried out by a person with imperfect knowledge of the vehicle, and who therefore does not immediately remember the precise position to insert the hand under the hood in order to operate said operating pushbutton. The object of the present invention is to provide a safety device of the initially stated type, in which the described drawback is obviated. This object is attained by a safety device forming part of a mechanism for locking a swinging hood against opening, said mechanism comprising release means arranged to release a hook rigid with the hood to allow it to open, and said safety device comprising a flat spring arranged to engage said hook to prevent the hood opening after it has undergone a predetermined swinging movement following its release, said flat spring having a first end fixed to a plate rigid with the vehicle body and its second end provided with an operating pushbutton and being flexurally deformable, by pressing said pushbutton, from a first deformed configuration, in which the spring is engaged by said hook on termination of said predetermined swinging movement of said hood in order to form a safety means for preventing the hood opening, to a second deformed configuration in which said spring is released from said hook to allow complete opening of the hood, characterised in that said hook is provided with an active edge arranged to cooperate with said spring and having a profile such as to flexurally deform said spring into a third deformed configuration when said hood is in its locked position, said third deformed configuration substantially corresponding to said second deformed configuration, the position of said operating pushbutton on the end of said flat spring being chosen such that when said spring is in said third and second configuration, said pushbutton is under the hood whereas when said spring is in said first configuration, the pushbutton projects by a predetermined amount from the hood to indicate the pushbutton position. The present invention will be more apparent from the detailed description given hereinafter by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of the basic parts of the safety device according to the invention; Figure 2 is a plan view of the device in a first operating configuration; Figure 3 is a section through the device of Figure 2 on the line 3-3; Figure 4 is a plan view of the device according to the invention in a second operating configuration; Figure 5 is a section through the device of Figure 4 on the line 5-5. The safety device according to the invention, indicated overall by the reference numeral 1, and shown in Figure 1, forms part of a mechanism for locking a swinging hood 2 against opening. The purpose of this mechanism is to keep a motor vehicle hood locked, and in particular the hood which closes an automobile engine compartment. The hood 2 moves by substantially swinging about an axis, not shown, so as to be able to pass from a completely open configuration to a completely closed configuration, in which the front edge 3 or another equivalent part of the hood rests on a suitable seat 4 of the vehicle body. The release mechanism comprises substantially release means which are arranged to release a hook fixed to the lower surface of the hood, for example by means of a plate 6, and a further plate 7 fixed in a substantially horizontal position on the vehicle body, and which is provided with a slot 8 into which the hook 5 is inserted when the hood 2 is in its closed configura­ tion, as can be clearly seen in Figure 3. In said position, a suitable stop element, not shown, for the hook 5 engages the hook in order to keep the hood locked in said configuration. The manually operable release means also comprise elastic means able to raise the hood from its closed configuration when said means have been operated in order to open the hood. The safety device according to the invention comprises a flat spring 10 of any suitable shape, the end 11 of which is fixed to the plate 7, and to the other end of which there is fixed an operating pushbutton 12. Conveniently, said spring comprises a pair of substantially orthogonal arms 13 and 14 and is arranged to flexurally deform in a horizontal plane which is substantially that of the plate 7. For this purpose, suitable lugs 15 are provided for guiding the flat spring during its deformation. The arm 13 of the flat spring 10 is disposed substantially at the centre of the slot 8 so as to cooperate with the active edge 15 (Figures 3 and 5) of the hook 5. The flat spring 10 is arranged to form a safety means to prevent opening of the hood, in the manner described hereinafter, and is therefore flexurally deformable from a first configuration 16 shown in Figure 5 in which the spring is hooked by the hook. This first configuration is obtained after the hood 2, following its release, has undergone a swinging movement of predetermined width. The flat spring 10 can also be moved into a second deformed configuration, indicated by 17 in Figure 5, in which said spring is released from the hook 5 to allow complete opening of the hood. According to the invention, the active edge 15 of the hook 5, arranged to cooperate with the flat spring 10, has a profile such as to flexurally deform the spring into a third deformed configuration indicated by 18 in Figure 3, when the hood 2 is in its closed position. This third configuration substantially corresponds to the second configuration 17, as can be clearly seen by ocmparing Figures 3 and 5. Consequently the active edge 15 comprises a first substantially rectilinear portion 19, substantially orthogonal to the plane of the hood 2, a second flat portion 20 forming a predetermined angle with the preceding, and a third portion 21 substantially in the shape of a circumferential arc which defines the internal cavity of the hook. That end of the hook 5 which faces the flat spring 10 lies substantially on the same straight line as the first flat portion 19, as can be clearly seen in Figure 3. The position of the operating pushbutton 12 on the end of the arm 14 of the flat spring 10 is chosen in such a manner that when this spring is in the aforesaid second and third configurations 17 and 18, shown in Figures 5 and 3, the pushbutton is under the hood 2 and internal to the edge 3 which frontally bounds the hood, whereas when the spring is in the aforesaid first configu­ ration 16 (shown in Figure 5), the pushbutton projects by a predetermined amount from the edge 3 of the hood, as can be clearly seen in Figure 4. The operation of the described safety device is as follows. When the hood is in its closed position and the locking mechanism is in its locking configuration, the various parts of the device are in relative positions shown in Figures 2 and 3. The hook 5 is completely inside the slot 8 and the edge 3 of the hood 2 rests on the corresponding seat 4 of the vehicle body, and a locking element (not shown) for keeping the hood in its closed configuration is inserted into the third portion 21 of the hook 5. In this configuration, as can be clearly seen in Figure 3, the flat spring 10 is in its aforesaid third configuration 18 in contact with the first portion 19 of the hook edge. In this configuration, as can be clearly seen in Figure 2, the operating pushbutton 12 is located under the hood behind the front edge 3 of the hood. When the locking mechanism is operated in order to cause the hood 2 to open, the locking element of the hook 5 is withdrawn from the hook, and thus the hood, under the action of the elastic means which cause it to open, moves into the configuration of Figure 5 after undergoing a swinging movement of predetermined width. The hood becomes locked in this configuration by the action of the flat spring 10 which, elastically urged against the active edge of the hook 5, moves into the portion 21 of its contour to lock the hood against opening. As the flat spring 10 has undergone a certain swivel movement in moving from the third configuration 18 of Figure 3 into the first configuration 16 of Figure 5, the pushbutton 12 has moved beyond the edge 3 of the hood 2 to lie outside the hood in order to indicate the position in which this pushbutton is located. At this point the operator, who from the location of the pushbutton 12 has exactly identified the position in which he has to act to release the safety device and obtain complete opening of the hood, operates this pushbutton to further deform the flat spring 10 so moving this into its aforesaid second configuration, indicated by 17 in Figure 5, in which the hood 2 can be moved into its open configuration. When the pushbutton 12 is outside the hood 2, it also acts as an indicator for indicating that the hood locking mechanism has been released and thus acts as a further safety means for the driver. It is apparent that modifications can be made to the described embodiment of the invention but without leaving the scope of the inventive idea.

Claims: 1. A safety device forming part of a mechanism for locking a swinging hood against opening, said mechanism comprising release means arranged to release a hook rigid with the hood to allow it to open, and said safety device comprising a flat spring arranged to engage said hook to prevent the hood opening after it has undergone a predetermined swinging movement following its release, said flat spring having a first end provided with an operating pushbutton and being flexurally deformable, by pressing said pushbutton, from a first deformed configuration, in which the spring is engaged by said hook on termination of said predetermined swinging movement of said hood in order to form a safety means for preventing the hood opening, to a second deformed configuration in which said spring is released from said hook to allow complete opening of the hood, characterised in that said hook is provided with an active edge arranged to cooperate with said spring and having a profile such as to flexurally deform said spring into a third deformed configuration when said hood is in its locked position, said third deformed configuration substantially corresponding to said second deformed configu­ ration, the position of said operating pushbutton on the end of said flat spring being chosen such that when said spring is in said third and second configuration, said pushbutton is under the hood whereas when said spring is in said first configuration, the pushbutton projects by a predetermined amount from the hood to indicate the pushbutton position. 2. A device as claimed in claim 1, characterised in that the profile of said edge comprises a first substantially flat portion orthogonal to the plane of said hood, and a second flat portion forming a predetermined angle with the first portion, that end of said hook facing said spring lying substantially on the straight line to which said flat portion pertains. 3. A device as claimed in claim 2, characterised in that said active edge and said hook are formed on a plate fixed to said hood. 4. A device as claimed in one of the preceding claims, characterised in that said flat spring comprises at least one pair of ortogonal arms, of which a first arm has one end fixed to said pushbutton and the second arm is arranged to cooperate with said active edge of said hook. 5. A device as claimed in claim 4, characterised in that said flat spring is fixed to said plate connected to the vehicle body, said plate being provided with a slot into which said hook is inserted.

Inventors: PORTIGLIOTTI, SERGIO
Applicants: FIAT AUTO S.P.A.
Application year: 1986
Main classification: E05B65
IPC codes: E05C19, E05B65