SPECIFICATIONLatches for panelsThis invention relates to latches for panels intended to close an opening in a structure and more particularly to latches for panels of the foregoing type which are hinged along one edge of the opening with the latch mounted on the opposite edge of the opening and being adapted to serve as a stay to hold the panel in an open position as well as securing it in a closed position. A known latch of this type comprises a toggle link having a first element connected to the panel by a first pivot pin and a second element connected to the frame by a second pivot pin and to the first element by a third pivot pin.
Latches of this type are commonly mounted with the axes of the various pivot pins parallel to the hinge axis of the panel. For example, such a latch is disclosed in a patent specification EP-A-0049983.
However, when such latches are applied to an opening roof of a vehicle, they suffer from the disadvantage that, in the closed position, the links project below the frame surrounding the opening in the vehicle roof into the interior of the vehicle, where they constitute a hazzard with which a vehicle occupant's head could make contact during an accident. It has already been proposed, in the periodical publication "Engineering". May 1984, page 361, to overcome this disadvantage by mounting a latch of the abovementioned type with the axes of its pivot pins extending in a horizontal direction perpendicular to the hinge axis of the panel.This enables the latch to be mounted on the forward facing surface of the rear edge of the frame surrounding the opening in the vehicle roof, with all the components of the latch above the bottom of the frame at all times except when the latch is being moved between its closed position and an open position. The latch has two open positions, in one of which the third pivot pin is level with the second pivot pin and the panel is in a half-opened position. However, this latch suffers from the disadvantages that a substantial axial force is imposed on the hinges of the panel as the toggle links go over-centre and that it is not possible to secure the panel in more than one intermediate position between its fully closed position and its fully open position.
According to the invention in one aspect, a latch for a panel which is mounted in a frame by means of a hinge comprises a toggle link having a first element connected to the panel by a first pivot pin and a second element connected to the frame by a second pivot pin and to the first element by a third pivot pin, the three pivot pins having their axes perpendicular to the axis of the hinge and the first pivot pin engaging in a slot in a member which projects from one surface of the panel and extends parallel to the hinge axis of the panel.
The first pivot pin is located at one end of the slot when the panel is in its closed position in the frame. Preferably a cam formation is provided on the member in which the slot is formed for engagement with a complementary formation on the first element of the toggle link to retain the first pivot pin at the other end of the slot when the panel is in an open position.
According to the invention in another aspect, a latch for a panel which is mounted in a frame by means of a hinge comprises a toggle link having a first element connected to the panel by a first pivot pin and a second element connected to the frame by a second pivot pin and to the first element by a third pivot pin, wherein the three pivot pins have their axes perpendicular to the axis of the hinge, the second element of the toggle element carries an internally serrated ring mounted with its axis coincident with that of the third pivot pin and a locking member is mounted on the first element for movement between a locked position in which it engages with the serrated ring on the second element and a free position in which it is disengaged from such serrations, the movable member being resiliently biased into its locked position and having a handle which projects from the first element on the opposite side of the third pivot pin to the first pivot pin.
Thus, when the locking member is in its locked position, relative angular movement between the two elements of the toggle link is prevented. Consequently, the panel can be locked at any position between its fully closed position and its fully open position in which the first and second pivot pins are spaced apart to the maximum extent.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:Figure 1 is a perspective view of the top of a motor car fitted with an opening roof of the type referred to above, with the panel in the open position;Figure 2 is a cross-sectional view of a latch in accordance with the invention fitted to the opening roof illustrated in Figure 1, but with the panel in the closed position;Figure 3 is a cross-sectional view taken on the line 3 - 3 in Figure 2 and showing the section line 2 - 2 on which Figure 2 is taken;Figure 4 is a cross-sectional view similar to Figure 3 but with the panel in an intermediate position between its closed and fully open positions;Figure 5 is a cross-sectional view similar to Figures 3 and 4 but showing the panel in its fully open position;;Figure 6 is a cross-sectional view taken on the line 6 - 6 in Figure 5; andFigure 7 is a cross-sectional view taken on the line 7 - 7 in Figure 6.
Referring to Figure 1, the roof 10 of a motor car has an opening which is filled by a panel 12 hinged along its leading edge 14 to a frame 16 which bounds the opening. A latch 18 at the rear of the panel 12 is arranged to hold the panel in a fully open position, as illustrated, in the fully closed position in which the panel 12 is level with the vehicle roof 10, and in a multiplicity of intermediate positions between the closed position and the fully open position.
Referring now to Figures 2 and 3, the latch 18 comprises a first toggle link 20 and a second toggle link 22. The toggle link 20 carries a pivot pin 24 near one end. The pin 24 engages in a horizontal slot 26 in a downwardly projecting part of a bracket 28 which is secured to the underside of the panel 12 adjacent to the rear edge thereof so as to be approximately parallel to the adjacent part of the frame 16.At its other end, the first link 20 is connected to the second link 22 by a pivot pin 30.
The other end of the second link 22 is connected by a pin 32 to a bracket 34 which is secured to the frame 16.
When the links 20 and 22 are in the position shown in Figure 3, with the pin 24 below the pin 32, the panel 12 is pressed firmly down on a resilient seal 35 which is secured to the frame 16. The lower link 20 does not project below a trim strip 36 which is secured to the frame 16 and serves to cover the headlining 38 (not shown) on the interior of the vehicle roof 10.
Turning now to Figure 4, when it is desired to open the panel 12, the links 20 and 22 are pivoted about the pivot pin 32 through 90 degrees in a clock-wise direction (as viewed in Figures 3 and 4) so as to bring the pivot pin 24 to a position level with the pivot pin 32. The two pivot pins 24 and 32 at the ends of the links 20 and 22 are now at the same level but the angular position of the first link 2O relative to the second link 22 has not changed.
During the first 45 degrees of this movement, the pin 24 moves along the slot 26, thus avoiding the imposition of any lateral stress on the hinge on the front edge 14 of the panel 12. Subsequently, the pin 24 is retained at the left hand end of the slot 26 (as viewed in Figures 3 and 4) by engagement of the end of the link 20 with a cam formation 38 on the bracket 28.
As shown in Figure 5, when it is desired to open the panel 12 to a greater extent than illustrated inFigure 4, the [ink 20 is pivoted in an anti-clockwise direction about the pin 30 so as to increase the distance between the pins 24 and 32, the end of the link 20 remaining in engagement with the cam formation 38.
Turning now to Figures 6 and 7, in order to secure the link 20 at any desired angular position relative to the link 22, the link 20 is formed with a cylindrical recess 40 in the face abutting the link 20, the axis of the recess 40 being coincident with that of the pin 30. Axially extending serrations 42 are formed on the cylindrical wall of the recess 40.
An elongate recess 44 in the abutting face of the first link 20 accommodates a slider 46 which has an elongate aperture 48 through which the pin 30 projects. The slider 48 carries a protuberance 50 which projects into the cylindrical recess 40 and which has complementary serrations on the face confronting the serrations 42. The slider 46 is biased by means of a spring (not shown) in a direction to bring the serrations on the protuberance 50 into engagement with the serrations 42. A projecting end of the slider 46 carries a handle 52 and a flange 54 is formed on the first link 20 adjacent to the handle 52 so that disengagement of the serrations may be effected by squeezing the handle 52 and flange 54 together. The two links 20 and 22 may thus be secured in any desired position.
The pivot pins 24, 30 and 32 are shown in Figures 3, 4, 5 and 7 as being headless. It will be appreciated that, as shown in Figures 2 and 6, all three pins have heads to prevent relative axial movement of the components which are pivotally mounted thereon.