Panel Joint Bracket Connector Plastic Knock Down K4240

The K4240 Knock Down Connector In Nineteen Photographed Positions

Nineteen frames were shot for this panel joint bracket and they cover both halves of the pair, in both colours, from the outside and from the side where the two halves actually meet. That is more views than a connector this small usually gets, and it is deliberate: a knock down connector is bought on the strength of how the two halves engage, and the engagement is exactly what a single front photograph hides.

The connector is two moulded parts, not one. The plate half is a flat T with two countersunk seats, screwed to the first panel. The hook half is a bracket with a tapered neck and a hook that slides over the tongue of the plate, screwed to the second panel. The two halves of the connector are fitted separately, and the joint is made by pushing the second panel until the hook drops over the tongue.

What makes this a knock down connector rather than a fixed joint is that the engagement is open on one side. The hook holds the tongue against the panel face and against a shoulder, so the joint resists being pulled apart and still releases when the panel is lifted and drawn back. On flat pack furniture that is the whole point: the piece is delivered in panels and built once, and the same joint comes apart again when it has to move.

The Plate, The Hook And The Shoulder

The shoulder inside the jaw is the part of this connector that decides whether the joint stays tight. Without a shoulder the connector hook would ride along the tongue until it met the panel, and every joint in the run would sit at a slightly different depth. With the shoulder the hook stops at the same place every time, so panels line up flush along a carcass instead of being adjusted one by one.

The tapered neck does the second job, which is taking up the slack that moulding tolerances leave. As the hook is pushed on, the taper wedges the jaw wider and then lets it close behind the tongue, so the connector is tight on the first push rather than after a few assembly cycles. That is also why the connector is moulded rather than bent: a metal part would take a set and go loose.

Two screw holes in the connector plate, one seat each side of the tongue, keep the plate flat against the panel while the hook pulls on it. A single screw would let the plate cock over and the tongue would then sit at an angle, which is the commonest reason a knock down connector releases under load: not the hook, but a plate that was never held flat in the first place.

What The Drawing Marks

One frame is the drawing and it marks this panel joint bracket in six figures, spread across a side view and a plan view. The plan view carries the plate: 32 millimetres between the two screw centres, 16 millimetres across the plate, and 8 millimetres from each hole centre to the end of the plate. The same plan carries the tongue at 10 millimetres across and 16 millimetres long, and the side view carries the neck at 20 millimetres outside and 14 millimetres inside.

The 32 millimetre connector hole spacing is the figure that decides whether this connector drops onto an existing hole pattern. It is also the figure that is easiest to get wrong: a plate drilled for a different spacing will still hook up, and it will still pull the joint closed, but the second screw will not find its hole and the plate will sit on one fixing. That is why the spacing is quoted separately from the plate size rather than left to the drawing alone.

The two connector neck figures, 20 outside and 14 inside, are the ones to check against a panel. The outside figure is how far the connector stands off the panel face when it is screwed down, and the inside figure is the clearance the hook has to pass through. On a thin panel or a tight rebate, those two numbers decide whether the connector can be used at all.

The Names This Connector Sells Under

The same pair of mouldings is bought under several names and three of them are used here. It is a plastic panel connector when the material and the job are named together, which is how a distributor orders it against a picture. It is a knock down connector when the assembly method is the point, because that is what separates it from a fixed corner bracket. And it is a panel joint bracket when the shape is the point, since the plate half is a bracket and the joint is what it makes.

All three names point at the same two mouldings, the same tongue and the same hook, so a quotation answers whichever one is on the enquiry. What is worth confirming before an order is the screw: the seat is moulded for a countersunk head and the plate is thin, so a pan head stands proud and a screw that is too long breaks out through the panel.

One more name needs care. A shelf support and this connector are sold by the same distributors and both come in white plastic. A shelf support carries a board; this connector joins two panels and comes apart again. The frames show two halves and an open jaw, which a shelf support does not have, so the two can be told apart from the pictures.

Where A Knock Down Connector Is Used

The commonest place for this connector is flat pack furniture: a wardrobe, a bed frame or a desk that is delivered as panels and built once. The connector holds the joint while the piece is in use and releases when it has to be taken apart, which is why it is specified on furniture that is expected to move rather than on furniture that is glued and forgotten.

The second place for the connector is a shop fitting or a display unit, where panels are assembled on site and taken down again at the end of a season. The third is a repair: where a fixed joint has failed and the panel cannot take another screw in the same place, a knock down connector can be set slightly to one side and still hold the corner square, because the two halves do not need to share a hole.

The limits are worth stating plainly. This connector holds a panel joint together and it does it without tools, but the connector is an assembly part, not a structural one: it is not sold as a rated load bearing fitting and nothing on these frames claims a load figure. Where a joint carries real weight, the connector holds alignment while a mechanical fixing carries the load.

White And Black On The Frames

Both colourways were photographed because the colour is a specification, not a decoration. White covers melamine, painted board and the inside of a wardrobe where the connector has to disappear against the panel. Black covers dark board, metal frames and the fittings behind a cabinet where a white part would show the moment a door is opened.

The colour is moulded through rather than painted, so it does not chip at the jaw, which is the one place on this connector that rubs every time the joint is used. A painted part loses its colour at the hook first and then reads as worn while the rest of the fitting still looks new, and on a knock down connector that happens the first time the piece is taken apart.

The two colours are the same moulding and the same figures, so a mixed order is a packing decision rather than a tooling one. What is worth agreeing is the ratio: a wardrobe carcass takes the white and a bed frame takes the black, and an order that is all one colour tends to come back for the other.

Short Answers On This Connector

• Connector type: two-piece knock down connector, plate half and hook half.
• Connector size: 32 mm hole spacing, 16 mm plate width, 10 mm tongue, 20 mm neck outside.
• Connector fixing: two countersunk screws in the plate, two in the hook half.
• Connector colours: white and black, moulded through.
• Connector joint: made by pushing the hook over the tongue, released by lifting the panel.
• Connector duty: an assembly part for panel joints, not a rated load fitting.
• Connector packing: sold by the set, the hundred or the thousand, screws quoted separately.

How The Joint Is Made And Released

The connector plate half goes on first, screwed to the panel that will be the fixed side, with the tongue standing off the face. The connector hook half goes on the second panel, positioned so that when the two panels are brought together the jaw lines up with the tongue. The joint is then made by pushing the panel along the tongue until the shoulder stops it.

Release of the connector is the reverse and it is not a lever job. The panel is lifted slightly to take the weight off the hook, then drawn back along the tongue. A knock down connector that has to be forced is either on the wrong plate or has been assembled with the hook upside down, and forcing it is what breaks the jaw.

On a production line the two connector halves are fitted with the panels flat, before assembly, and the screws are driven at a low clutch setting. A countersunk connector seat takes a flush head and nothing else, and a driver set too hard splits the plate at the hole, which is the one failure this connector cannot be repaired from.

Questions A Buyer Asks About This Connector

• How many parts in a set? Two, one plate half and one hook half.
• How many screws? Two in the plate, two in the hook half; quoted separately.
• What screw head? Countersunk, so the head finishes level with the plate.
• What is the hole spacing? 32 mm between the two centres in the plate.
• Which colour should I order? White for light board, black for dark board and metal frames.
• Can it be taken apart? Yes, that is what a knock down connector is for.
• Is it strong enough for a bed? It holds the joint; the bed frame carries the load.
• Does it come with a cover cap? No cap on this connector; the seats stay open.

Checks Before A Connector Goes Into A Joint

A two-piece connector is only as good as the position of the two halves, so these are the checks that decide whether the joint goes together on the first push.

• Plate and hook marked from the same datum, because the connector has no adjustment once screwed.
• Hole spacing checked against the panel before drilling, since the plate takes two screws only.
• Panels offered up dry, so the hook is seen to meet the tongue square without the jaw riding an edge.
• Screw length checked against the panel thickness, so the tip cannot break out through the face.
• Jaw checked for moulding flash on a sample from every carton, because flash stops the hook seating.
• Connector counted against the set, since a panel joint takes one and a box takes four.
• Joint cycled twice before packing, because a knock down connector that releases hard on the bench will not release at all once the piece is loaded.

Two Halves, One Joint

The reason this connector is sold as a pair rather than as a single moulding is that each half has one job and neither can do the other. The plate carries the tongue and takes the screws; the hook carries the jaw and takes the slack. A connector that tries to do both in one piece needs the panel to be slid sideways into place, which is impossible on a carcass that is already standing.

Fitting the two halves is therefore a marking job rather than a drilling job. The hook half sets the depth, the plate half sets the line, and the connector holds whatever line the two were given. Where a run of joints has to line up, the connector halves are marked from one datum along the whole carcass before any screw is driven, and the panels then assemble in any order.

Connector Notes For A Buyer

• Connector halves: one plate half and one hook half, sold as a set.
• Connector plate: flat T with two countersunk seats either side of the tongue.
• Connector hook: open jaw with a shoulder, so every joint stops at the same depth.
• Connector taper: takes up moulding slack on the first push, not after a few cycles.
• Connector screw: countersunk head only; a pan head would stand proud of the connector.
• Connector hole spacing: 32 mm, the figure to check before any panel is drilled.
• Connector clearance: 14 mm inside the jaw, 20 mm outside the plate face.
• Connector colour: white and black from the same tool, so the ratio is a packing call.
• Connector release: lift the panel, draw it back along the tongue, never lever the jaw.
• Connector duty: holds a panel joint, does not carry a rated load.
• Connector sample: cycle one connector on offcuts before a production run.
• Connector carton: the count per connector set is marked on the box.
• Connector finish: moulded through, so there is no paint to chip at the jaw.
• Connector packing: loose, or bagged per connector set, as agreed.

Who Supplies This Connector

This panel joint bracket is supplied by Guangzhou Gorgeous Intelligent Technology Co., Ltd., a furniture and architectural hardware business whose range covers hinges, drawer slides, handles, stays, legs, castors, locks, corner brackets, connecting plates and the fittings that hold panel furniture together. The company works to export orders: quantity, colour, screw specification, packing, carton marking and shipping documents are agreed before production rather than after it. On a moulded connector the tongue, the hook and the taper are all fixed by the tool, so those are agreed with the model number and checked against a master sample, which is the only way a second order can be guaranteed to engage the way the first one did.

Send the model number K4240 with the number of sets, the colour or colours, the screw specification, the panel thickness and the destination port, and confirm the 32 and 16 millimetre figures against the drawing at the same time. Samples are available before a production order so the two halves can be screwed to offcuts and cycled, which is the fastest way for both sides to agree that the hook seats without flash and that the joint releases without force. The drawing, the packing list and whatever test documentation we hold for K4240 are issued on request, and delivery and payment terms are agreed order by order on the proforma rather than assumed from a previous order.