GB2167510A - Buckle - Google Patents

Abstract

An over-centre buckle 10 comprises a lever 12 pivotted at 14 in blind bores in side walls 20 of a channel-shaped frame 11 and latchable thereto by means of a one-piece plastics latch 40 having an actuating portion 41 and two sliding latching feet 46 arranged on flexible legs 44. Feet 46 pass through holes (35, Figure 3 not shown) in the side walls (30) of the lever 12 and enter blind bores (25, Figure 10 not shown) in the side walls 20 of the frame 11. <IMAGE>

Description

SPECIFICATION Buckle The present invention relates to a buckle and more particularly to a buckle suitable for application in the transport and cargo control industries for tightening straps and securely holding them when tight.

Existing holders are made of a relatively large number of metal parts. Some of the parts, especially pivot members and/or latching members usually protrude from the sides of the buckle which can cause the buckle to snag in use. The buckles are also relatively expensive to construct. Further problems of insufficient strength and corrosion also arise. To some extent these have been overcome by the use of stainless steel but at a relatively high cost.

The present invention seeks to overcome or reduce one or more of the above disadvantages.

According to a first aspect of the present invention there is provided a buckle comprising a lever member pivotally mounted on a frame member and latching means for securing together the lever member and the frame member, wherein the latching means comprises a onepiece member having an actuating portion connected to one or more latch portions via one or ore respective resilient portions.

According to a second aspect of the present invention there is provided a method of constructing a buckle from a plastics lever member having pivot pins protruding therefrom and a plastics frame member having recesses for the pivot pins therein, wherein at least one of said plastics members is moulded and, when it is removed from the mould and the plastics material thereof is still soft, said pivot pins are inserted in said recesses.

According to a third aspect of the present invention, there is provided a buckle comprising an inner lever member pivotally mounted within an outer frame member, the lever member having protruding pivot pins and/or protruding latching means and the frame member having corresponding blind bores to receive said pivot pins and/or said latching means, whereby neither said pivot pins nor said latching means protrude beyond the frame member.

According to a fourth aspect of the present invention there is provided a one-piece latching member for a buckle comprising an actuating portion connected to one or more latch portions via one or more resilient portions. The latching member is preferably of plastics material and the or each resilient portion is preferably constituted by a flexible leg.

A preferred embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, of which: Figure 1 shows a front view of a buckle according to the present invention comprising a frame and a lever mounted therein; Figure 2 is a side view of the buckle of Figure 1; Figure 3 is a front view of the lever of the buckle; Figure 4 is a side view of the lever; Figure 5 is a side view of the frame of the buckle; Figure 6 is an enlarged front view of a spring member of the buckle; Figures 7a and 7b are side and front views respectively of a spring-retaining member of the buckle; Figures 8, 9 and 10 are enlarged cross-sectional views of the buckle taken on the lines indicated in Figure 1; Figures 11 to 15 shows a modification of the buckle of which:: Figure 1 7 shows a front view of part of the frame, the view corresponding to the bottom of the view of Figure 1 with the lever removed; Figure 12 is an enlarged side sectional view of the modified buckle corresponding generally to the bottom of the view of Figure 2; Figure 13 shows a side view of the lever of the modified lever corresponding to Figure 4; and Figures 14 and 15 are enlarged cross-sectional views of the modified buckle respectively corresponding to Figures 8 and 10.

Referring to the drawings a buckle 10 comprises a frame 11 and a lever 12 pivotally mounted therein, both of injection-moulded engineering plastics material. Frame 11 is substantially channel-shaped having side walls 20 and web portions 21,21' and having a large rectangular aperture 22 therein. Lever 12 is formed with integral pivot pins 14 which engage in respective blind bores 15 at the inside of walls 20 of the frame. The pins 14 are inserted in the bores 15 whilst the plastics material is stil soft. To assist in this at least one of the bores 15 has associated with it a slipway 16 in the side wall 20 of the frame 11.

The insides of the side walls 20 are also formed with mutually-aligned blind rectangular bores 25.

The side walls also have substantially pear-shaped aligned through holes 26.

The lever 12 comprises side walls 30 interconnected by shaped bars 31,32 and by a web portion 33. Web portion 33 terminates in a wall 34 perpendi cularthereto and extending across the lever 12. As shown in Figure 2, bars 31,32 have curved surfaces around which passes a strap 80. The path of the strap 80 is shown by a heavy line in Figure 2. The side walls 30 have mutually-aligned substantially pear-shaped through holes 36, which in the closed position of the buckle are also aligned with holes 26 in the frame. Side walls 30 also have mutuallyaligned rectangular through holes 35 which in the closed position of the buckle are also aligned with blind bores 25 in the frame.

The projections 38 extend from the inside of side walls 30 parallel to and spaced from web portion 33.

Mounted between the web portion and the projections 38 is a generally planar one-piece plastics spring member 40. Member 40 comprises an actuating part 41 with a small step 42 in one of its major surfaces. Two rigid projections 43 and two flexible legs 44 extend from the actuating part 41. Mounted at the ends of legs 44 are feet 46 having elongate through holes 47 therein. AT the portions of feet 46 facing projections 43, there are provided projections 48. The outer ends of the feet 46 are provided with latch portions 50 which pass through apertures 35 in the lever to latchingly engage in bores 25 in the frame. The inner ends of feet 46 are designated 51 in Figures 6 and 10.

To retain the spring member 40 in position there is provided a generally rectangular retaining plate 60 of relatively rigid plastics material. Three circular pegs 61 project from a major surface of the plate. In use, pegs 61 engage in three corresponding annular sockets 62 projecting from the web portion 33 of lever 12. The plate has step portions 64 at its sides and a projecting ledge 66 along one of the longer edges. Step portions 64 engage the opposite sides of projections 38 from spring member 40. Ledge 66 engages step 42 of the spring member 40 to limit outward axial movement thereof, ie downward movement in Figures 1 and 2.

The above-described buckle is assembled as follows. As soon as the plastics frame and lever (or at least one of them) are removed from their moulds, and while the plastics material is still soft, the pivot pins of the lever are inserted in the recesses of the frame. Thereafter the spring member is located with two of the annular sockets 62 on the lever entering the inner ends of holes 47 of the spring member, and with latch portions 50 passing through apertures 35.

Projections 43 fit behind projections 38. The retaining plate 60 is then attached, with plugs 61 fitting in sockets 62. The buckle is now ready for use and a strap 80 is threaded therethough as shown in Figure 2 with the buckle open.

In use, the strap is tightened by closing the buckle.

As the lever is pivoted into parallel relationship with the frame, the ends of the latch portions 50 are first depressed into apertures 35 by the side walls 20 of the frame. After a final pivotal movement to bring the frame and lever precisely parallel, the latch portions 50 spring out, due to the resilience of legs 44, to enter the bores 25 and securely fasten and positively lock the frame and lever together. The buckle is arranged to act in an over-centre manner so that in its closed position the latch is not under load.

Where a plurality of the buckles is used along the base of the load on a lorry, a TIR security cable may be passed through the aligned apertures 26,36 of all the closed buckles to prevent unauthorised opening thereof.

To release the buckle, actuating part 41 is manually depressed. This causes legs 44to flex inwardly, thus withdrawing latch portions 50 from bores 25.

Inward axial movement of part 41 (ie upwards in Figures 1 and 2) is limited by projections 43 engaging projections 48. The lever 12 is now free for pivotal movement relative to the frame 11, thus releasing the tension in trap 80.

The above-described buckle has numerous advantages. The construction of the pivot 14, 15 gives a smooth external finish with no protruding parts to cause snagging; in addition it does not require additional components such as rivets, pins etc. It employs a one piece latching or locking arrangement (ie spring member 40) which is totally enclosed and is not under load when the buckle is closed.

Since it is totally enclosed, the latching arrangement cannot be accidentally released or prised open.

The buckle is made completely of plastics material and is resistant to sea water and diesel; in particular the problem of rust is entirely avoided. It can withstand prolonged exposure to strong sunlight and also to low temperatures (down to at least 30"F offrost i.e. -17"C).The buckle combines the advantages of positive locking and over-centre arrangements. it can withstand a working load in excess of 3000 Ibs (1360 kg) and has high impact resistance.

Various modifications may be made to the above described buckle. For example retaining plate 60 may be omitted if desired. In addition the bores 15 andlor 25 may be through holes, although this results in a less smooth exterior. Also the pivot pins 14 could be on the frame 11, with bores 15 arranged in the side walls of the lever 12. Moreover, only one latching portion 50 need to be provided.

Figures 11 to 15 show a modified buckle in which the frame is provided with a pair of limit elements in the form of shoulders or ledges 71,72. The shoulders 71,72 are located in the corners formed between the side walls 20 and the web portion 21'. As shown in Figure 11, the inner ends of the ledges form steps 73.

Referring now to Figures 12 and 13, itwill be noted that the lever is shaped differently from the lever of Figure 4 in that the side walls 30 form steps 74. In the closed, unstressed condition of the buckle there is a 0.5 mm clearance gap 76 between steps 73,74.

When , however, the buckle is closed and the strap 80 is under a high load, the plastics material of the buckle elastically stretches slightly. Thus steps 73 and 74 come into mutual engagement and the applied load is then shared between the pivot pins 14 and the steps. By relieving some of the load applied to the pivots, the elements 71,72 increase the overall load capacity of the buckle.

One of the shoulders 71,72 and its corresponding step 74 may be omitted if desired.

The buckles may be employed in a wide range of fields and their use is not restricted to tightening straps around cargoes.

Claims (22)

1. A buckle comprising a lever member pivotally mounted on a frame member and latching means for securing together the lever member and the frame member, wherein the latching means comprises a one-piece member having an actuating portion connected to one or more latch portions via one or more respective resilient portions.

2. A buckle according to Claim 1, wherein the frame member is generally channel-shaped having at least one web-portion and two mutually-facing side walls, and the lever member is mounted within the channel.

3. A buckle according to Claim 2, wherein the lever member is generally channel-shaped having two mutually-facing side walls with pivot means on the outside thereof which engage with pivot means on the inside of the side walls of the frame member.

4. A buckle according to Claim 3, wherein the pivot means comprise pivot pins integrally formed with one of said members and aligned bores in the other of said members.

5. A buckle according to Claim 4, wherein the pivot pins are integrally formed with the lever member and the bores in the frame member are blind bores.

6. A buckle according to Claim 4 or 5, wherein at least one of the bores has a slipway adjacent thereto to facilitate insertion of the pivot pin during assembly.

7. A buckle according to any of Claims 2 to 6, wherein the latching means is mouned on the lever member and the or each latch portion is arranged to enter a bore in a side wall of the frame member.

8. A buckle according to Claim 7, wherein the bore for the or each latch portion is a blind bore.

9. A buckle according to Claim 7 or 8, wherein, before entering the blind bore in the side wall of the frame member, the or each latch portion passes through an aligned through bore in the respective side wall of the lever member.

10. A buckle according to any of Claims 7 to 9, wherein the latching means is retained in position by a plate attached to the lever member.

11. A buckle according to Claim 10, wherein the plate is formed with means to limit outward axial movement of the actuating portion of the latching means.

12. A buckle according to any preceding claim, wherein the actuating portion and Itch portion(s) of the latching means are provided with respective projections, the projection(s) on the actuating portion engaging with the projection(s) on the latching portion(2) to limit inward axial movement of the actuating portion.

13. A buckle according to any preceding claim, wherein the lever member and the frame member are each provided with at least one limit element, the elements mutually engaging upon an axial load being applied to the closed buckle.

14. A buckle according to Claim 13, wherein the limit element on the frame member comprises a shoulder located at the inside of one of the side walls thereof and the limit element on the lever member comprises a step in the corresponding side wall thereof.

15. A buckle according to any preceding claim and which operates in an over-centre manner.

16. A buckle according to any preceding claim wherein the frame and lever members and/or the latching means are made of plastics material.

17. A buckle substantially as herein described with reference to Figures 1 to 10 or Figures 11 'tO 15 of the accompanying drawings.

18. A method of constructing a buckle from a plastics lever member having pivot pins protruding therefrom and a plastics frame member having recesses for the pivot pins therein, wherein at least one of said plastics members is moulded and, when it is removed from the mould and the plastics material thereof is still soft, said pivot pins are inserted in said recesses.

19. A method of constructing a buckle substantially as herein described with reference to the accompanying drawings.

20. A buckle comprising an inner lever member pivotally mounted within an outer frame member, the lever member having protruding pivot pins and/or protruding latching means and the frame member having corresponding blind bores tore- ceive said pivot pins and/or said latching means, whereby neither said pivot pins nor said latching means protrude beyond the frame member.

21. A one-piece latching memberfora buckle comprising an actuating portion connected to one or more latch portions via one or more resilient portions.

22. A latching member for a buckle substantially as herein described with reference to the accompanying drawings.