HARTVIGSSON, Marcus (Grevevägen 28, Värnamo, S-331 52, SE)
WESTMAN, Johan (Pukgränd 5, Gislaved, S-332 31, SE)
HARTVIGSSON, Marcus (Grevevägen 28, Värnamo, S-331 52, SE)
| CLAIMS 1. A safety belt buckle comprising a main member (1) and at least one tongue member (2) to be inserted in the main member (1) and releasably connected thereto by means of a spring biased locking mechanism (L) therein, a manually movable unlocking knob (6) being provided in the main member (1), characterized by a security arm (8) pivotally movable in the plane of the main member (1) and spring biased to a position lockingly engaging a locking part (9) of the locking mechanism in its position for keeping the at least one tongue member (2) connected to the main member (1), the unlocking knob (6) being provided with a portion (7, 7') for pivoting the security arm (8) out of said engagement when manually operated for releasing said connection. 2. A buckle according to claim 1, wherein the unlocking knob (6) is provided with an operating leg (7) for engagement with the security arm (8) by an operating point (T). 3. A buckle according to claim 2, wherein the security arm (8) is arranged at the side of the locking mechanism opposite the unlocking knob (6), whose operating leg (7) extends past the locking mechanism. 4. A buckle according to claim 2, wherein the security arm (8) has an indentation (8") for engagement by the operating point (7') of the operating leg (7). 5. A buckle according to any one of the preceding claims, wherein the security arm (8) has a spring finger (8') for accomplishing its spring bias. 6. A buckle according to claim 5, having a housing for the main member (1), wherein a lower housing member (3) is provided with a pivot pin (3 ') and an engagement surface for the spring finger (8 ') at its inner side. 7. A safety belt assembly comprising a safety belt buckle as claimed in any one of the preceding claims and attached to a plurality of belts (10, 11, 12). 8. A child safety seat comprising an assembly as claimed in claim 7. |
Technical Field
The present invention relates to a safety belt buckle comprising a main member and at least one tongue member to be inserted in the main member and releasably connected thereto by means of a spring biased locking mechanism therein, a manually movable unlocking knob being provided in the main member.
The invention is especially concerned with, but not limited to, use in a vehicle child seat, where the child can be strapped to the seat by three belts, one over each shoulder and one between the legs of the child.
Background
Safety belt buckles, where the at least one tongue member is attached to one belt and the main member to another belt, are known in the art. They are used for strapping a person in a vehicle to a seat and thereby prevent injuries to the person in case of an accident. It is of great importance that the intended function of the buckle to connect the tongue member to the main member is maintained at all instances, except when a disconnection or release by the unlocking knob is desired.
Especially, an inadvertent disconnection or release may exceptionally occur under the influence of hard blows or shocks on the buckle, causing high g-forces. Examples of prior attempts to prevent undesired disconnection or release of a safety belt buckle under the influence of g-forces are shown in US-A-5,555,609, US- B2-6,550,112 , US-A-5,369,855, and US-B2-7, 124,480.
Buckles according to all these examples suffer from one or more disadvantages with regard to function, security or cost for manufacture and/or assembly.
Summary
The object of the invention is to obviate all, or at lease some of, these disadvantages and thereby provide a new safety belt buckle which is improved over prior art. This is obtained - in a safety belt buckle as defined by way of introduction, by a security arm pivotally movable in the plane of the main member and spring biased to a position lockingly engaging a locking part of the locking mechanism in its position for keeping the at least one tongue member connected to the main member, the unlocking knob being provided with a portion for pivoting the security arm out of said engagement when manually operated for releasing said connection.
In a practical embodiment, the unlocking knob is provided with an operating leg for engagement with the security arm by an operating point. According to an embodiment, the locking part of the locking mechanism is movable out of the latter in an unlocking movement on the opposite side of the unlocking knob. Preferably, the security arm is arranged at the side of the locking mechanism opposite the unlocking knob, whose operating leg extends past the locking mechanism. The security arm preferably has an indentation for safe engagement by the operating point of the operating leg.
Further, the security arm preferably has a spring finger for accomplishing its spring bias.
Normally, a buckle of the kind defined has a housing for the main member. According to an embodiment of the invention, a lower housing member may be provided with a pivot pin and an engagement surface for the spring finger at its inner side.
The objects of the invention are also achieved by a safety belt assembly comprising a safety belt buckle as defined above, and a plurality of belts. Preferably, the main member is towards its end in provided with a slot for attachment of one of the belts. Further, each tongue member is provided with a slot for attachment of another one of said belts. Such an assembly may be provided in a vehicle child seat.
According to an aspect, a child safety seat may be provided with a safety belt assembly as defined above. Further features of the invention and its embodiments are set forth in the appended claims.
Brief Description of the Drawings
Embodiments of the invention will be described in further detail below with reference to the accompanying drawings, in which Fig. 1 is an isometric view from above of a safety belt buckle with a dismantled lower housing member (but without an upper housing member), the buckle being provided with a device according to an embodiment of the invention,
Fig. 2 is an isometric view from below of the buckle shown in Fig. 1 but without the lower housing member, Fig. 3 is an isometric, larger scale view of an unlocking knob of the buckle shown in Figs 1 and 2,
Fig. 4 is a side view to a larger scale of a security arm of the buckle shown in Figs 1 and 2, and Fig. 5 is a side view of a child safety seat secured to a car seat and provided with a safety belt assembly according to an embodiment of the invention.
Detailed Description
The safety belt buckle B shown in Figs 1 , 2 and 5 is generally intended for use in a child safety seat CS for a motor vehicle. The purpose of the buckle is to releasably connect three straps or belts 10, 11, 12 to hold a child C in the seat CS. Other uses and purposes may, however, be contemplated.
The buckle generally comprises three functional parts, which in Figs 1 and 2 are shown in their assembled and locked condition. These three parts are a main member 1 and two tongue members 2. The main member 1 has a locking mechanism L, which generally is known per se, does not itself form a part of the invention and is not further described. It has a buckle housing, preferably made of a plastic material. Only a lower buckle housing member 3 is illustrated in the drawings, but a corresponding upper housing member (not shown) is arranged on the opposite side of the locking mechanism. The two housing members are held together in a conventional, not illustrated way to form a complete housing for the main member 1 of the buckle.
The main member 1 is towards its end provided with a slot 4 for attachment of a belt 12 (shown in dotted lines). The two tongue members 2 are provided with tongues which are not visible in the shown assembled condition but are insertable into the locking mechanism of the main member 1 and configured to be locked by appropriate means of the locking mechanism. Each of the two tongue members 2 is provided with a slot 5 for attachment of a belt 10 and 11, respectively.
When the two tongue members 2 are inserted into the main member 1 , they will be automatically snap-locked therein by the spring biased locking mechanism. In order to manually release the two tongue members 2 from the main member 1 , there is provided on the latter an unlocking knob 6 which may be pushed for movement in the plane of the main member 1 to the left in Fig. 1 against spring bias.
If the arrangement so far described is subjected to a heavy stroke or blow, the locking mechanism can under extreme conditions inadvertently open for releasing the two tongue members 2 from the main member 1. The purpose of the improved buckle structure is to prevent such unintentional opening of the buckle.
For accomplishing this purpose, the buckle is supplemented with an operating leg 7 on the unlocking knob 6 and with a security arm 8 pivotally attached to a pivot pin 3 ' on the inside of the lower buckle housing member 3, as is illustrated in Fig. 1. The security arm 8 is thus pivotally movable in the plane of the main member 1 and its locking mechanism.
The operating leg 7 is preferably formed as an integral part of the unlocking knob 6, which preferably is made of a plastic material, and extends generally perpendicularly thereto (past the locking mechanism 3) to its side opposite the unlocking knob 6 or underside. It is there ended with an operating point 7'.
The security arm 8, which is preferably made of a plastic material, is provided with a thinner spring finger 8' for application against the inside of the lower buckle housing member 3. It is also provided with a small indentation 8" for cooperation with the operating point 7' of the operating leg 7.
The locking mechanism of the buckle has such a design that a locking part 9 thereof, shown in Fig. 2, in an unlocking pivoting movement, operated by the unlocking knob 6, is lifted above the surrounding surface of the locking mechanism. After thus having been pivoted, the locking part 9 will remain in this new unlocking position for allowing withdrawal of the tongue members 2 and later easy insertion of them, ending with the reverse pivoting of the locking part 9 and locking of the tongue members 2. Figs 1 and 2 illustrate the buckle in this locking position, which also may be regarded as its rest or use position. In this position, the security arm 8 is spring biased by its spring finger 8 ' to be applied against the locking part 9 for preventing the latter from any pivoting or lifting movement or in other words for preventing any inadvertent opening of the buckle under the influence of g-forces introduced by external shocks or blows.
If on the other hand the buckle is to be opened by will for release of the tongue members 2, the unlocking knob 6 is operated by a pushing movement to the left in Fig. 1. The operating point 7' of the operating leg 7 will herewith push the security arm 8 in the counter-clockwise direction as viewed in Fig. 2, so that the latter leaves its engagement with the locking part 9, which accordingly will be free to perform its pivoting movement operated by the unlocking knob 6. A practical embodiment of a safety belt buckle provided with an inventive g- force security device has been shown and described. Many modifications are possible within the scope of the appended claims.