Securing device

Abstract: A device for securing furniture panels at right angles to one another includes a holding member comprising a plug-like body portion (2) which is fitted in a recess in a major surface of one of the panels. The plug has a front wall (6) which is exposed at an edge of the panel and is substantially flush with the panel edge. An opening (12) is provided in the front wall (6) which extends into the body portion (2) to define a chamber (10) which accommodates a securing member (16). The top wall (4) of the plug, which is exposed at the major surface of the first panel, includes an opening (22) which connects with the chamber (10) allowing access to tighten the securing member (16) to engage a second, substantially perpendicular panel and draw it towards the first. According to one aspect of the invention the lower surface (28) of the chamber (10) is formed to allow unobstructed movement of the securing member (16) when it is inserted through the top wall opening (22) to a position substantially perpendicular to the second panel with its leading end protruding through the opening (12) in the front wall (6). According to another aspect of the invention a third opening (18) is provided opposite the opening (12) in the front wall (6) to allow alternative access for insertion of the securing member (16) before the plug is positioned in the panel recess. This third opening (18) and the opening in the top wall (22) are separated by a bridge portion of the plug-like body (2).

Description: This invention relates to devices for securing furniture panels. In particular it relates to the type of devices which are used to secure two panels at right angles to one another, the edge of one panel being in contact with a major surface of the other panel. A first known device of this type comprises a body portion made of a plastics material which has a bottom surface, and surrounding wall portions substantially perpendicular thereto. The top of the body portion has a generally open structure enabling a securing member in the form of a screw to be inserted in the body portion substantially parallel to the bottom thereof. The body portion is adapted to be fitted in a recess in a major surface of one of the panels to be joined. A front wall portion of the body portion is positioned substantially flush with an edge of the panel, and is adapted to allow the screw to be driven through it to engage the second panel, whilst retaining the screw head within the body portion of the securing device. When the joint is tightened the two panels are drawn together. The device may be provided with a separate cap adapted to cover its open top after insertion and driving of the screw. Such prior art devices are weak. Although they are adequate for fixing non-structural panel members of an item of furniture in place, for example shelves, they do not provide a strong enough joint to be used for fixing together major structural components of assembly furniture. Another prior art device of the same general type has a plug-like body portion which also has a top and a bottom wall connected by surrounding walls which include a front wall. The top wall has a recess in it extending almost the entire length of the body portion from the front wall towards the rear. At the front end wall of the device, which fits flush against the edge of a panel, the recess is deep enough to accommodate the head of a screw. This end wall has a generally U-shaped opening in it which is open at the top surface of the device and has a constriction slightly narrower than the diameter of the shank of the screw. The other end of the recess slopes upwardly towards the rear of the device giving access for a screwdriver. The device is intended for use in fixing shelves and the like. The plug-like body portion is positioned in a recess in the first panel or shelf, whilst the screw is driven into the other panel to a predetermined depth. The first panel or shelf is positioned with the recess of the fixing device over the protruding screw head and, once they are aligned, it is pushed down so that the screw head is received in the recess, snap-fitting into the U-shaped opening in the front end wall. The screw can then be tightened using a screwdriver at an angle to the screw axis by virtue of the sloping portion of the recess. At the bottom of the U-shaped opening there is a step down to the floor of the recess which prevents a screw being easily inserted via the sloping surface because it cannot readily slide into position in the U-shaped opening. A third prior art device of the same general type has a plug-like body portion which has both a top and a bottom wall which are connected by surrounding walls. The body portion of this securing device is also adapted to be fitted in a recess in a major surface of a panel, with a front wall positioned flush with an edge of the panel. This type of device is stronger than those described above, but has the disadvantage that insertion of the screw is more complicated. The body portion of the device is provided with a hinging capability allowing a screw to be inserted when it is open, and arranged to be snapped shut with the screw in position before insertion in the recess in the panel surface. An opening is provided in the top wall of the body portion through which the tip of a screwdriver can be inserted at an angle to the screw axis to drive the screw. A suitable screw for use in this and the previously described prior art devices, is one which is adapted to be driven at an angle to its axis. An example of this type of screw is described in European Patent No. 0 112 030. The need to drive the screw at an angle to its axis arises because it is preferable for the screw to be parallel to the plane of one panel and perpendicular to the plane of the other to form a strong joint. In achieving this arrangement there is no access to drive the head of the screw from a direction coincident with the screw axis, in the normal way. The third type of prior art device described above is inherently strong, but has the disadvantage of being relatively complicated, and therefore costly, to make. The unit cost can be reduced by the use of cheaper types of screws, but this gives rise to further problems as cheaper screws have a greater tendency to break whilst being tightened during assembly of furniture, or if the panels are subjected to forces tending to move them laterally with respect to each other. A broken screw could only be removed, and a new one inserted, by taking out the whole of the securing device. This almost inevitably leads to damage of the panel in which the device has been positioned, and usually results in damage to the walls of the recess so that it is no longer capable of anchoring a replacement securing device. The panel thus becomes unusable. DE-U-8502414 discloses a device for use in securing panels at right angles to each other, comprising a plug-like body portion which in use is fitted in a recess provided in a major surface of one of said panels, said body portion having a top wall, a front wall and a chamber connecting with a first opening provided in said front wall and being adapted to retain a securing member within the body portion, said chamber further connecting with a second opening extending into the body portion from said top wall, said second opening being adapted to enable insertion of said securing member in the chamber and provide access for driving the securing member for securing said panels. The invention aims to provide a device as defined in the last preceding paragraph which overcomes, at least in part, some of the disadvantages of the prior art outlined above. To this end the invention provides such a device characterised in that said chamber extends through the body portion to a third opening opposite said front wall, said third opening providing alternative access for insertion of the securing member in the chamber prior to fitting of the device in said panel recess and wherein said second and third openings are separated by a bridge portion. Preferably, the chamber is provided on its inner walls with one or more longitudinal ribs arranged to locate and retain the securing member in position in the chamber. The device may include a said securing member retained within the chamber. The securing member may be a screw adapted to be driven by a screwdriver positioned at an angle to the screw axis. The diameter of the first opening may be smaller than the diameter of the bore of the chamber, thereby providing means by which the head of the screw is retained inside the body portion when the screw is driven. The screw-head retaining means may be provided as a step formed by the change in diameter, a portion of said step being chamfered to facilitate insertion of the screw in the chamber via said second opening. The second opening may be provided with a chamfer at a relatively rearward edge thereof. Preferably, the chamber is provided with a lower surface formed to permit unobstructed movement of the inserted securing member to a position substantially perpendicular to said front wall with its leading end protruding through said first opening. Preferably, the portion of the top wall between the front wall and the second opening comprises at least a fifth of the length of the top wall. The first opening may be elongated in a direction perpendicular to said top wall in which case, the upper portion thereof may be arranged to locate the securing member in a desired location relative to the front wall when the securing member is driven for securing said panels. The elongate first opening may be offset so that said desired location is central relative to the front wall. A device in accordance with the invention enables a securing member in the form of a screw to be inserted or removed whilst the body portion remains in position in the recess in the panel surface, and also provides an inherently strong joint. In order that the invention may be more clearly understood embodiments thereof will be described with reference to the accompanying drawings, in which: Figure 1 is a plan view of a device for use in securing panels at right angles to each other; Figure 2 is a sectional view taken along the line A-A' in Figure 1 and showing a screw in position in the device, and in a position for insertion; Figure 3 is a sectional view also taken along the line A-A' in Figure 1 but showing two panels which are joined, the screw being in its driven position; Figure 4 is an end view of the device of Figure 1, looking in the direction of arrow B; Figure 5 is a plan view of an alternative embodiment of a device for use in securing panels together; Figure 6 is a sectional view taken along the line A-A' in Figure 5 and showing a screw in position in the device, and in a position for insertion; Figure 7 is a sectional view also taken along the line A-A' in Figure 5 but showing two panels which are joined, the screw being in its driven position; and Figure 8 is an end view of the device of Figure 5, looking in the direction of arrow B. The device of the first preferred embodiment shown in Figures 1 to 4 comprises a plug-like body portion 2 made of a suitable plastics material and having a top wall 4 which projects slightly beyond the side walls of the plug-like body in the form of a flange 5. This flange is more pronounced towards the front edge of the top wall 4. It serves to locate the body portion 2 at a suitable depth in a recess formed in the surface of a panel, and provides a neat finish by covering the edges of the recess when the body portion is in position. One of the walls of the body portion 2 is flat and forms a front wall 6 which is fitted flush with an edge of the panel 19 in which the device is positioned. The other wall is generally arcuate, so that the plug has an overall cylindrical shape. The outer surface of the arcuate wall is provided with a series of circumferential ribs 8 which serve to anchor the body-portion 2 securely in the recess into which it is inserted. The plug-like body portion 2 is substantially hollow and has a first opening 12 which is provided in the front wall 6 and connects with a chamber 10 which extends axially into the body portion 2 and substantially perpendicular to the front wall 6. The chamber additionally connects with a second opening 22 which extends into the body portion from the top wall 4. The bore of the chamber 10 is larger than the diameter of the first opening 12 a step being formed by the change in diameter so that the head 14 of a screw 16 within the chamber 10 is retained inside the body portion 2, when the screw 16 is driven along the chamber axis. The chamber 10 extends across the full diameter of the body portion 2 from front to back of the device to a third opening 18 in a portion of the arcuate wall opposite the front wall 6. This third opening enables the screw 16 to be readily dropped into the chamber 10 during the production process of the device. Longitudinal ribs 20 are provided on the inner side walls of the chamber 10, towards the top of the body portion 2. These serve to locate and retain the screw 16 in position in the chamber 10 when the securing device is in transit. The second opening 22 connects with the chamber 10 so that a screw 16 can be inserted into the chamber 10 through the top wall 4 of the body portion 2. To make this insertion easier the rear edge of the opening 22 has a chamfer 24 providing more room for the screw to move into the chamber 10, and also enabling a screwdriver to be more easily positioned correctly for driving the screw through the chamber 10. A portion 26 of the step formed by the difference between the diameter of the chamber 10 and the first opening 12, which portion is in line with the axis of the screw 16 when it is inserted through the top wall 4, is also chamfered to give room to allow the screw 16 to pivot into the chamber 10 to a position in which its axis lies along the axis of the chamber 10. The provision of the second opening 22 firstly allows access for driving the screw with a screwdriver placed at an angle to the screw axis, and secondly enables screws to be inserted and removed when the body portion 2 is in position in the recess of the panel surface. Thus broken or otherwise damaged screws can be removed and replaced without the possibility of damage being caused to the panel. Turning now to Figures 5 to 8 a second embodiment of the device will be described. The device shown in Figures 5 to 8 is similar to the device shown in Figures 1 to 4. Accordingly, like reference numerals in these figures designate like or similar parts. This embodiment of the device also comprises of a plug-like body portion 2 with a top wall 4 extending beyond the side walls of the body portion 2 to form a flange 5 and has generally the same configuration as the first embodiment of the device. However, as can best be seen in Figure 8 the first opening 12 is elongate and may be generally oval or D-shaped, extending in a direction from top to bottom of the plug-like body portion 2. As can be seen the top and bottom ends of the opening 12 are generally curved in the embodiment shown, and the upper end is semi-circular, centred on a point generally central in the front wall 6. This positioning helps to locate the screw 16 when the joint is fastened, as will be explained below. As in the previously described embodiment the diameter of the chamber 10 is larger than the diameter of the opening 12, so that the chamber 10 can accommodate the head 14 of the screw 16 but the opening 12 cannot, so that the screw head 14 is retained inside the body portion when the screw 16 is driven. As before, the chamber 10 is arranged to extend through the full length of the body portion 2 to a third opening 18 in a portion of the arcuate wall opposite the front wall 6. The body portion 2 is further provided with a second opening 22 which extends from the top wall 4 into the body portion to connect with the chamber 10. The second opening 22 is positioned towards the rear of the body portion 2 and has a chamfer 24 on its rear edge to provide additional room for insertion of the screw 16 therethrough into the chamber 10. The portion of the top wall between the front edge of the oval opening 22 and the front wall of the plug-like body portion 2 is at least 1/5 and preferably 1/3 to 1/2 of the overall length of the top of the device. It is therefore substantial enough to provide at least the front portion of the device with sufficient rigidity to resist compressive forces. The lower surface 28 of the chamber 10 is contoured to slope gently up (as viewed in Figures 6 and 7) towards the lower edge of the elongate first opening 12 with no obstructions. This allows the tip of the screw 16 to slide along the bottom of the chamber 10 and pivot into the first opening 12 as the screw 16 takes up its position in line with the chamber axis. The tip of the screw 16 will move into the lower part of the first opening 12 and as the joint is tightened, the screw 16 will locate in the upper semicircular part of the opening 12 so that it takes up a central position relative to the front wall 6. As can be seen in Figures 1 to 8, the passageway formed by the second opening 22 in the top wall connecting with the chamber 10 is generally L-shaped and is dimensioned to allow the screw 16 to be guided through a generally arcuate path from insertion in the top of the device to its position in the chamber 10 ready to be driven. The device, as previously explained, is intended for use with screws adapted to be driven by a screwdriver positioned at an angle to the screw axis. Such screws are provided with cavities or undercuts within their heads which are designed to permit movement of the screwdriver tip in the head so that the screwdriver can be used at an angle to the screw axis. Figures 6 and 7 show an example of such a screw which is described in detail in European Patent No. 0 112 030, assigned to the assignees of the current application. This screw is moulded with a rectangular cavity in its head, below the usual screwdriver recess in the top of the screwhead and is one example of so-called angle-drive screws, of which several types are known.

Claims: A device for use in securing panels at right angles to each other, comprising a plug-like body portion (2) which in use is fitted in a recess provided in a major surface of one of said panels, said body portion having a top wall (4), a front wall (6) and a chamber (10) connecting with a first opening (12) provided in said front wall and being adapted to retain a securing member (16) within the body portion, said chamber further connecting with a second opening (22) extending into the body portion from said top wall, said second opening being adapted to enable insertion of said securing member in the chamber and provide access for driving the securing member for securing said panels, characterized in that said chamber extends through the body portion to a third opening (18) opposite said front wall, said third opening providing alternative access for insertion of the securing member in the chamber prior to fitting of the device in said panel recess and wherein said second and third openings are separated by a bridge portion. A device according to claim 1, wherein the chamber is provided on its inner walls with one or more longitudinal ribs (20) arranged to locate and retain the securing member in position in the chamber. A device according to claim 1 or 2, including a said securing member (16) retained within said chamber. A device according to claim 3, wherein the securing member is a screw (16) adapted to be driven by a screwdriver positioned at an angle to the screw axis. A device according to claim 4, wherein the diameter of the first opening (12) is smaller than the diameter of the bore of the chamber (10), thereby providing means by which the head (14) of the screw is retained inside the body portion when the screw is driven. A device according to claim 5, wherein the screw-head retaining means is provided as a step formed by the change in diameter, a portion (26) of said step being chamfered to facilitate insertion of the screw in the chamber via said second opening (22). A device according to any preceding claim, wherein said second opening is provided with a chamfer (24) at a relatively rearward edge thereof. A device according to any one of the preceding claims, wherein the chamber (10) is provided with a lower surface formed to permit unobstructed movement of the inserted securing member to a position substantially perpendicular to said front wall with its leading end protruding through said first opening. A device according to any preceding claim, wherein the portion of the top wall between the front wall and the second opening comprises at least a fifth of the length of the top wall. A device according to any preceding claim, wherein the first opening is elongated in a direction perpendicular to said top wall. A device according to claim 10, wherein the upper portion of said elongate first opening is arranged to locate the securing member in a desired location relative to the front wall when the securing member is driven for securing said panels. A device according to claim 11, wherein said elongate first opening is offset so that said desired location is central relative to the front wall.

Inventors: HARLEY DAVID NORMAN, HARLEY, DAVID NORMAN
Applicants: TITUS TOOL CO LTD, TITUS TOOL COMPANY LIMITED
Application year: 1990
Main classification: F16B12
IPC codes: F16B12