This invention relates to a pipe bending apparatus and method.
Many applications require the use of pipes of substantial length which include portions bent at different angles and in different planes. For example, such pipes may be used as fuel lines, brake or hydraulic pipes in vehicles.
It has been proposed to provide a pipe bending apparatus comprising one or more bending heads, each arranged to rotate to provide bends in appropriate planes, the apparatus also including a pipe clamp adapted to hold the pipe during bending.
However, such machines have reliability problems, chiefly due to the effect of repetitive rotation of the bending heads causing wear on control wires and other components of the bending heads. They are also complex to manufacture and to programme.
Objects of the present invention are to provide a new or improved pipe bending apparatus and method and a new or improved pipe clamping head.
Viewed from a first aspect, the invention provides a pipe bending apparatus comprising at least one non-rotatably mounted pipe bending head; and a pipe clamping head comprising a body which is non-rotatably mounted on the apparatus and a clamp rotatably mounted within the body.
The pipe can therefore be clamped in the clamping head and bent by the bending head, the pipe subsequently being rotated by rotation of the clamp within the body of the clamping head to bring the axis of the pipe to the correct orientation relative to the non-rotatable bending head for the formation of the next bend.
The bending head and optionally the clamping head may be mounted for linear movement.
An end stop may be provided.
The apparatus may have control means for example a computer which may be programmable to produce a series of bends in the pipe.
In a preferred form, a pair of bending heads are provided, disposed at opposite sides of the clamping head. In a further embodiment, two or more pipe bending apparatuses are provided on a single machine having a common control means.
Viewed from another aspect, the invention provides a pipe clamping head for a pipe bending apparatus which comprises a two-part divided body adapted to be separated to allow insertion of a tube characterised in that it comprises:
a circular track defined by the body;
a slotted drive gear rotatably mounted in the body;
a first jaw having rolling means adapted to roll on the circular track and fixed to the gear;
a second jaw having rolling means adapted to roll on the circular track and pivotally mounted to the gear;
the arrangement being such that opening of the two-part divided body enables the second jaw to pivot open away from the first jaw to reveal the slot in said gear member to admit a pipe; and closure of the two-part divided body closes the two jaws together to grip the pipe and to permit the rolling means to roll on said circular track to rotate the clamp.
Preferably the rolling means comprise two rollers on the first jaw and one roller on the second jaw defining an equilateral triangle on closure of the two-part divided body.
The second jaw may be pivoted towards one end, and the other end of the second jaw may be provided with weight reducing means such as one or more apertures whereby the jaw tends to fall open under gravity on opening of the two-part divided body.
The invention also provides a pipe bending apparatus which includes a pipe clamping head as set out above.
Viewed from a further aspect, the invention provides a method of bending a pipe comprising the steps of inserting the pipe in a clamp of a pipe clamping head, having a non-rotatable body and a rotatably mounted clamp associated with the body; performing a bending operation on the pipe by means of a non-rotatable bending head; rotating the clamp relative to the body of the pipe clamping head; and performing another bending operation.
The second bending operation may be carried out with the same bending head or with another non-rotatable bending head of the apparatus.
The method may include the step of moving the bending head(s) linearly after the bending operation(s).
Preferably, the method is carried out using the apparatus according to the first aspect of the invention.
A machine embodying the invention will now be described in more detail by way of example only with reference to the accompanying drawings in which,
- Figure 1 is a diagrammatic view of a double bed pipe bending machine,
- Figure 2 is a diagrammatic view of a mechanism of a clamping head,
- Figure 3 is a detail of clamping jaws of the clamping head,
- Figure 4 is an isometric view of the clamping head,
- Figure 5 is a scrap diagrammatic illustration of a bending head.
- Figure 6 is a top plan view of the clamping head.
Referring firstly to Figure 1 of the drawings, a pipe bending machine is generally indicated at 10 and comprises a machine bed 11 having end supports 12. On the bed 11, there are provided a slidably mounted end stop 13, and a pair of slidably mounted bending heads 14. Similar stop and bending heads are provided on the opposite side of the centre line 15 of the machine bed in order to provide a twin machine but this is shown merely by way of example. The following description will apply to one side of the machine and it will be understood that the other side of the machine carries out the same functions using the same drive and control means so as to double production.
Between the bending heads 14, there is provided a clamping head 16 which will be described in more detail with reference to Figures 2, 4 and 6. Operation of the bending head 14 is illustrated in Figure 5.
The machine itself incorporates a slideway on the machine bed 11 so as to permit sliding of the end stop 13 which is then fixed at a selected position, and to permit sliding of the bending heads 14. The clamping head 16 is fixed relative to the machine bed but could alternatively be made slidable if required.
Turning to Figures 2-4 of the drawings, a clamping head is generally indicated at 16 and comprises a two-part body, the first part 17 being fixed and the second part 18 being movable away from the first part 17. It will be appreciated that this movement is transverse of the machine bed 11 and is intended to enable a pipe extending generally longitudinally of the machine bed 11 to be inserted into the clamping head and removed from it.
Within the clamping head 16, there is provided a split gear wheel 19 having peripheral teeth which engage an upright worm 20 mounted in the fixed part 17 of the body. The gear wheel is mounted in suitable bearings (not shown) and has a slot 21 extending from its edge to its centre. The slot 21 is suitably sized to receive a pipe to be clamped.
Each of the body parts 17, 18 has a part circular track 22, 23 provided on each of its outer faces, facing along the machine. At each face, a pair of jaws 24, 25 are mounted for rotation within the track 22, 23 on three adjustable rollers 25, 26, 27.
The jaw 24 is captive to the gear wheel 19 and remains in position on the part 17 of the body which is fixed. This jaw has two of the rollers 25, 26. It also has a part circular central recess 28 to receive a pipe to be clamped. The recess has a liner of suitable size.
The other jaw, 25, is pivotally mounted at 29 to the gear wheel 19. Thus, when the movable part 18 is slid away from the fixed part 17 in the direction of the arrow of Figures 4 or 6, the jaw 25 is allowed to pivot open.
Separation takes place when the jaws are in the position shown in Figure 3. It will be seen that the jaw 25 has its face upright. It will be seen that the jaw 24 has its face upright and the jaw 25 has its pivot 29 at its lower most part. The uppermost part of the jaw 25 can be cut away to reduce the weight.
As the part 18 of the body moves away from the fixed part 17, the jaw 25 pivots about the point 29 so as to flop open. This is achieved gravitationally and for this reason it can be useful to reduce the weight of the upper part of the jaw or otherwise to arrange the weight distribution to ensure a positive opening action.
The gear wheel 19 within the clamping head 16 is arranged so that its slot 21 lies at an angle of 45° at the time of opening of the body of the clamping head. The pivoted jaw 25 flops open so that its upright edge 30 becomes aligned with the slot 21 of the gear wheel, enabling a pipe to be inserted or removed. The pipe locates in the part circular recess 31 defined at the centre of the jaw and, on moving the body part 18 back towards the fixed body part 17, the pipe is clamped between the two jaws which are held together by the two parts of the body.
It will be seen that a pipe inserted in the clamp can be rotated by rotating the gear wheel 19 using the worm 20. This is power driven by a motor, for example a stepper motor, so as to give precise indexing of the rotary jaws 24, 25 using the rollers 26, 27 running on the track 22, 23.
In order to bend a pipe to a complex shape, the apparatus is controlled by a programmable computer (not shown) to perform a series of bending operations.
Firstly, the slidable parts of the machine are brought to datum positions at the start of a bending operation. The clamping head 16 is then opened and a pipe is inserted as described. The clamping head is closed to clamp the pipe in position. A first one of the bending heads 14 is moved to the appropriate point and a bend at the appropriate angle is made in the pipe. The clamping head 16 is caused to rotate if necessary to bring the pipe into the correct orientation for the next bend which is formed at the appropriate position, usually by the other bending head 14. Each of the bending heads 14 is moved stepwise inwardly towards the clamping head 16 as successive bends are made. Appropriate rotations are carried out between bends so as to produce the complex shape required.
The bending heads 14 are of generally known type and will not be described in great detail. They each comprise a pair of rollers 32, 33 between which the pipe is fed. The roller 33 is moved arcuately about the centre of the roller 32 to perform a bending operation as diagrammatically illustrated in Figure 5. A forked nylon support 34 is provided to steady the pipe during the operation. The bending head 14 is mounted on a universal joint extending laterally of the machine bed 14 which provides the rotation of the grooved roller 33. However, the bending head itself does not rotate relative to the machine. It is merely longitudinally slidable along the machine bed 11 under control of the control means.
By way of safety device, a suitable photoelectric beam arrangement is provided between the machine frame elements at 35, breaking of the beam by the operator shutting off the drive to the machine.
The invention provides a way of rapidly producing complex bends in a pipe by the use of a rotary clamping head at a fixed position which is driven by pneumatic means and through the worm and gear arrangement. The pipe bending head or heads do not rotate. There are therefore no wires or air lines subject to flexure during the pipe bending process and the machine is capable of running for prolonged periods with limited maintenance. It is also fully programmable to produce complex three dimensional bends and, where a twin bed machine is provided as shown in Figure 1, the production rate can also be relatively high.