Pipe-bending alignment device

Details Pipe-bending alignment device Pipe-bending alignment device

1999-05-24

2002-05-14

Gutierrez, Diego (Department: 2859)

Geometrical instruments

Indicator of direction of force traversing natural media

With angle or shape determination

C033S529000, C033S533000, C033S534000

Reexamination Certificate

active

06385856

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to the field of fabrication and construction. In particular, the invention relates to the fields of plumbing and wiring. More particularly, the invention relates to the installation of pipe, conduit, and other pipe-like material, such as hydraulic and pneumatic tubing. Still more particularly, the invention relates to the accurate bending, for shaping and routing, of pipe, conduit, and other tube-like material in multiple planes.
2. Prior Art
In many fields, it is frequently necessary to bend pipe, conduit, and other tube-like items (hereinafter “pipe”). The need arises, for example, in the installation of electrical equipment, plumbing systems, and, generally, in construction work. Typically, a single pipe will have to be bent several times. There are two components of the bending process that must be carefully controlled when introducing multiple bends in a pipe: the bend-angle and the bend-plane. Thus, the pipe-bender must be able to accurately measure and control the bend-angle of each bend and the bend-plane, to ensure, for example, that the latest bend is in the desired plane.
It is useful to define a few terms. Reference has been made to a “bend-plane.” In order to see what is meant, consider a pipe with no bends in it. There is no plane defined at this point by the pipe regardless of how it is oriented. However, once a single bend introduced in the pipe (resulting in two pipe segments) a bend-plane is defined; it is the plane in which both segments lie (or, more carefully stated, the plane defined by the centerlines of the two segments). This bend-plane of course is only defined with respect to the pipe; its orientation in space is arbitrary and is determined by how the pipe is oriented. When the pipe is laid on a horizontal table, the table will be parallel to the bend-plane; the bend-plane is horizontal. Similarly, if the two-segment pipe is pressed flat against a vertical wall, the bend-plane is vertical.
It can be seen that one does not choose the first bend-plane; it will be defined by the two segments resulting from the bend. However, once that first bend is introduced, a bend-plane has been defined, and a subsequent bend in the pipe is either in that plane or out of it. The second bend will introduce a third segment in the pipe and the potential for two bend-planes, one—the first bend-plane—defined by the first and second segment, the other—the second bend-plane—by the second and third segment. Commonly, depending on the use to which the pipe is to be put, it will be desired that the first bend-plane and the second bend-plane are coincident, or, alternately stated, that the second bend-plane lie in the first bend-plane. This would be the case, for example, when the two bends are put in simply to cause an off-set pipe configuration, where all three resulting segments lie in the same plane, and the first and third segments are parallel to one another. Alternatively, it may necessary that the third segment be “out of” the first bend- plane, and that it be out of that plane by a specific angle, and a specific direction.
Although it is important to be able to determine the angle that a pipe segment resulting from a particular bend makes with a particular bend-plane, the most common use for a bend-guide device is to ensure that the segment resulting from a bend is in the bend-plane defined by the previous bend placed in the pipe. If a segment that is supposed to lie in that previously defined bend-plane does not in fact lie in it, one says that it is “dogged” or a “dogged bend” (from “dogleg”). The difficulty in making accurate multiple bends can be viewed simply in terms of making a second bend in a pipe, that is, in introducing a second bend after a first bend-plane has been defined. For example, inadvertently twisting the pipe or shifting the reference plane between the first and second bends will result in the undesired dogging. Devices for guiding pipe bending so as to control the angle-of-bend and for ensuring that the latest-formed bend segment lies in the previously defined bend-plane are therefore in great demand, as can be seen by the prior art. Since a bend-plane is defined by two adjacent pipe segments “created” by a bend, it is useful to also characterize a bend-plane as being defined by the bend (as an alternative to saying that the plane is defined by the two pipe segments that meet at the bend in question).
Simple devices including levels, plumbs, and protractors by themselves, and more elaborate guiding devices employing levels, plumbs, and protractors in combination, have long been employed to introduce bends of pre-determined angles in pipe and then to verify the angle-of-bend and to confirm that the resultant pipe configuration has the desired planarity. Some of these devices attach to the tool being used to bend the pipe and indicate the degree of bend as the pipe-bending tool operates. See, for example, Bergman (U.S. Pat. No. 4,622,837; issued 1986), which teaches the use of a spirit level built into the pipe-bending tool itself to indicate the angle of rotation of the tool from some pre-selected reference direction and, thus, the “instantaneous” angle of bend given to the pipe being bent on the tool. Devices of this type have a serious drawback in that they have no means of indicating or tracking a bend-plane, thereby making it difficult to ensure that a bend being introduced in a pipe lies in the plane defined by a prior bend. In devices like that of Bergman, one makes a subsequent bend in the pipe by sliding the pipe so that the part of the pipe in contact with the pipe-bending tool shifts from the first bend to the position where one desires to place the next bend. During this movement, it is easy to unknowingly twist the pipe enough to get dogging in the next bend, i.e., to cause the next bend segment to jut up out of the plane defined by the first bend. A similar pitfall exists with those guide-equipped tool-bending tools that are removed from the site of a first bend and re-attached to the pipe at the site of the desired second bend.
Traupmann (U.S. Pat. No. 2,824,381; issued 1958) teaches a bend-guide device that, instead of being integrated into the bending tool, is clamped around a segment of a pipe that is to be bent. It appears that the primary function of the Traubmann device is to introduce in-plane offsets into a pipe, the operation by which two bends, of equal angle and opposite sense, are introduced into a pipe so to produce three new pipe segments: a first segment, a second (middle) segment, and a third segment such that all three segments are in the same plane and the first and second segments are parallel to one another. In order to accomplish this task, the guide device of Traubmann must first be mounted on what is to become the middle segment of the offset and then, after the first bend has been introduced, the device must be moved to what is to be the third segment. A major disadvantage of the Traubmann device is that it can indicate direction only for the horizontal projection of the longitudinal axis of the pipe segment to which the device is attached. This means that re-clamping the device for making the second bend can introduce a twist that results in the third segment being out of the plane defined by the first bend. Of course, this problem arises with any bend being guided by the Traubmann device that is supposed to be in a defined plane; this device does not provide any way of ensuring that the bend is indeed in the desired plane. It is also noted that simply having to move and reclamp the Traubmann device is time-consuming. It means that for multiple bends not only does one have to move the pipe-bending tool along the pipe (common to all pipe-bending operations), but one also has to repeatedly reposition the guide device, which in any event does not provide guidance for ensuring that the new bend-plane is coincident with an earlier one.
There do exist recent prior-art devices that attempt to address the need for making several co-plana

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