Roll grooving apparatus is pivotally mountable on the support rails of a power drive unit by which the apparatus is driven and comprises a lower support including a drive shaft driven by the power unit and including the lower grooving roll, and an upper support member pivotally interconnected with the lower support member and rotatably supporting the upper grooving roll. A lever arm is pivotally mounted on the lower support member and is interengaged with the upper support member through a pin and slot arrangement, whereby pivotal displacement of the lever arm imparts pivotal displacement to the upper support member and thus movement of the upper grooving roll toward and away from the lower grooving roll. The lower support includes a stop which limits displacement of the lever in the direction which moves the upper grooving roll towards the lower grooving roll, thus to assure a desired depth for the groove in a workpiece, and the pivotal interconnection between the upper and lower supports is adjustable to provide for adjusting the groove depth and accommodating different pipe or tube sizes and thicknesses. The adjustment enables using the stop on the lower support member as a constant in connection with pipe size and thickness variables and enables optimizing the leverage advantage and the direction of application of force of the upper grooving roll relative to the lower grooving roll.
Dale A. Pulver, Colman A. Gulden Paul W. Gress
Original Assignee: Emerson Electric Co.
BACKGROUND OF THE INVENTION
This invention relates to the art of apparatus for performing work on tubular metal workpieces and, more particularly, to improved apparatus for roll forming grooves in metal tubes or pipes.
Roll grooving apparatus is, of course, well known and, generally, includes a lower housing rotatably supporting a driven lower grooving roll, and an upper housing supporting a rotatable upper grooving roll matingly contoured with the lower roll so that a tubular workpiece therebetween is provided with a peripheral groove upon relative rotation of the grooving rolls and advancement of the upper roll towards the lower roll. Generally the lower roll is rotated by the drive motor of a power unit, and when a workpiece is interposed between the upper and lower rollers, the driven lower roller imparts rotation to the workpiece which in turn imparts rotation to the upper grooving roll, and the latter is gradually advanced towards the lower roll to progressively form the peripheral groove in the workpiece.
Heretofore, upward and downward displacement of the upper roll supporting housing has been achieved through the use of threaded feed screw arrangements between the upper and lower housings and which include a feed screw component capable of accommodating a tool such as a wrench for manually rotating the feed screw. Often, the upper and lower housings are inter-engaged for linear displacement of the upper housing toward and away from the lower housing, whereby it will be appreciated that considerable time is required to set up and to perform a roll grooving operation on a tube or pipe. In this respect, the feed screw must be manually rotated in the direction to separate the grooving rolls to facilitate the insertion of the end of a tube therebetween, and the feed screw must then be manually rotated in the opposite direction to bring the upper grooving roll into engagement with the outer surface of the workpiece. Often, the feed screw arrangement includes an adjustable stop to limit downward movement of the upper housing to control the depth of the groove which may vary from one workpiece to another depending on such factors as the diameter of the workpiece, the material of the workpiece and the wall thickness of the workpiece. Such an adjusting mechanism generally includes a threaded nut on the feed screw which is adjustably positioned therealong by manually rotating the nut, whereby it will be appreciated that further time is required to prepare the apparatus for a given roll grooving operation. Once the necessary adjustments are made, the lower grooving roll is driven to rotate the workpiece and upper grooving roll, and the feed screw is manually rotated in the direction to displace the upper housing towards the lower housing, thus to displace the upper grooving roll toward the lower grooving roll to progressively form the peripheral groove in the workpiece. When the desired groove depth is reached, driving of the lower grooving roll is stopped and the feed screw is manually rotated in the opposite direction until sufficient clearance is provided between the two rolls to accommodate removal of the grooved workpiece from therebetween.
In addition to the time required to perform a roll grooving operation, and the relatively inefficient manner of operation thereof, the time required to manually rotate feed screw arrangements for displacing the grooving rolls relative to one another can result in damage to the workpiece which renders the latter unacceptable and/or damage or undesirable wear on the component parts of the roll grooving apparatus which shorten the life thereof. More particularly in this respect, if any problems occur during the roll grooving operation it is impossible to quickly release the grooving rolls so as to preclude damage to the latter, damage to the workpiece, or the imposition of undesirable forces on the rolls and other component parts of the roll grooving apparatus which lend to damage or excessive wear thereof. For example, it is necessary for the workpiece to be properly aligned with the roll axes during a roll grooving operation so that the track of the groove is transverse to the workpiece axis. Misalignment at the beginning of the operation can cause the track of the groove to be spiral relative to the workpiece axis causing the workpiece to "walk" axially outwardly from between the grooving rolls. If the upper grooving roll is not displaced from the workpiece immediately, the workpiece can be damaged to the extent that the grooving operation cannot be completed so as to provide an acceptable end product, and/or the workpiece can drop off the end of the rolls and subject the operator to injury. While the power to the drive unit can be interrupted immediately, time is required for the momentum in the transmission to be overcome, whereby the improper tracking engagement with the workpiece does not immediately stop. Likewise, the undesirable tracking cannot be quickly stopped where displacement of the upper grooving roll from engagement with the workpiece requires manual rotation of a threaded feed screw, especially if the operator is using a ratchet wrench and has to first reverse the wrench drive and then begin the reverse rotation of the feed screw.
In other roll grooving apparatus heretofore provided, the upper grooving roll supporting housing is pivotally attached to the lower housing, but displacement of the upper housing toward and away from the lower housing is still accommodated through the use of a feed screw arrangement. Therefore, the time required to space the grooving rolls for the insertion of a workpiece therebetween, as well as the time required to perform a roll grooving operation, is basically the same as with apparatus in which the housing members are linearly displaceable relative to one another. Moreover, for the same reasons discussed above, the feed screw arrangement is unsafe from the standpoint of the inability to quickly release the grooving rolls or otherwise interrupt the roll grooving operation.
Other problems attendant to both of the foregoing feed screw type roll groovers result from the fact that considerable torque is required to be applied to the feed screw during a roll grooving operation and is applied by the operator by rotating the feed screw about a vertical axis. It will be appreciated that the force required to achieve such rotation results in the imposition of directional forces against the apparatus in a horizontal plane which tend to promote misalignment between the apparatus and workpiece. This in turn promotes "walking" of the workpiece, especially at the beginning of the roll grooving operation. Such application of horizontal directional forces is of further concern from the standpoint of operator safety because there is the potential for tipping the apparatus, especially when the directional force is lateral to the working axis. Moreover, the rotational force which must be applied to the feed screw by the operator promotes the latter's imbalance during a roll grooving operation which is both tiring and hazardous from the standpoint of operator safety.
In a manner similar to the latter roll grooving apparatus, it is known to provide a pipe or tube cutter with a cutter wheel pivotally mounted on a support member for displacement toward and away from supporting rollers. A workpiece to be cut is interposed between the supporting rollers and cutting wheel and, in a manner similar to that described above, the pivotally mounted cutting wheel is advanced toward the rollers and against the workpiece by a feed screw mechanism during relative rotation between the workpiece and the cutting apparatus. Thus, as with the similar roll grooving apparatus, it is not possible to quickly disengage the cutting wheel from the workpiece during a cutting operation should it become necessary or desirable to do so and, following the cutting operation, it is necessary to manually rotate the feed screw mechanism in the opposite direction to reset the cutting wheel for the next cutting operation.
SUMMARY OF THE INVENTION
In accordance with the present invention, roll grooving apparatus is provided which advantageously minimizes or overcomes the foregoing and other problems and disadvantages encountered in connection with roll grooving apparatus heretofore available. More particularly in this respect, the support for the upper grooving roll in accordance with the present invention is mounted on the support for the lower grooving roll in a manner whereby the upper grooving roll is pivotal toward and away from the lower grooving roll, and a manually actuated lever arrangement is provided for imparting pivotal movement to the upper support member and thus the upper grooving roll. The lever arrangement advantageously avoids having to manipulate the upper roll support through the use of a feed screw arrangement and, in connection with the preparation for and performance of a roll grooving operation, minimizes the time and effort required on the part of the operator. In this respect, the upper grooving roll is readily displaced away from the lower grooving roll by the lever mechanism to facilitate the introduction of a workpiece therebetween and, likewise, the upper grooving roll is readily displaced toward the workpiece and lower grooving roll to initiate the roll grooving operation. Furthermore, the latter is achieved with less physical effort on the part of the operator and in less time in that the rotating of a feed screw through a wrench or the like is replaced by simple pivotal displacement of a lever arm to advance the upper grooving roll toward the lower grooving roll to progressively produce the peripheral groove in the workpiece therebetween. It will be appreciated too that the lever arm advantageously enables multiplying the working force applied to the upper grooving roll relative to the force applied to the lever arm by the operator, thus to further facilitate the ease with which roll grooving is achieved.
In addition to the foregoing advantages in connection with the preparation and performance of a roll grooving operation, the lever arrangement advantageously enables the operator to immediately disengage the upper grooving roll from the workpiece should a problem such as mis-tracking occur, thus to minimize or avoid damage to the workpiece. Moreover, such immediate release of engagement between the upper grooving roll and the workpiece can be achieved at any time during a roll grooving operation should it become necessary or desirable to do so. In addition to protecting the workpiece and/or component parts of the roll grooving apparatus from damage, the quick release afforded by lever actuation of the upper grooving roll provides improved safety for the operator by avoiding potential injury which could result from the workpiece walking off the end of the lower grooving roll, and by avoiding the operator having to use a tool such as a wrench to rotate a feed screw and which tool can both interfere with the operator's concentration and can become disengaged from the feed screw and accidentally dropped into the vicinity of the rotating parts and workpiece.
Preferably, the pivotal connection between the support for the upper grooving roll and the support for the lower grooving roll is adjustable to facilitate varying the depth of the groove in a workpiece and to better accommodate workpieces of different diameter and having different wall thicknesses. Further, the adjustment enables maintaining an alignment between the upper and lower grooving rolls which optimizes the directional application of force therebetween during a grooving operation thus optimizing the lever advantages. Still further, the adjustment capability enables providing the apparatus with a fixed or constant stop point for the lever arm in the direction of displacement thereof in performing a roll grooving operation.
Accordingly, it is an outstanding object of the present invention to provide improved roll grooving apparatus for roll forming a peripheral groove in a tubular metal workpiece.
Another object is the provision of roll grooving apparatus of the foregoing character which is structured to minimize the time and effort required to prepare the apparatus for and to perform a roll grooving operation on a workpiece.
A further object is the provision of roll grooving apparatus of the foregoing character which is structured to provide for the immediate release of the working engagement between the grooving rolls and a workpiece therebetween at any time during a roll grooving operation.
Still another object is the provision of roll grooving apparatus of the foregoing character comprising upper and lower grooving rolls and wherein the upper grooving roll is supported for pivotal displacement toward and away from the lower grooving roll through a lever arrangement which optimizes the application of force to the displaceable upper grooving roll and facilitates immediate release of the force at any time during a roll forming operation.
Yet another object is the provision of roll grooving apparatus of the foregoing character wherein the pivot axis for the upper grooving roll support is adjustable to facilitate the roll grooving of workpieces of different diameter and wall thickness and to vary the groove depth while optimizing the directional application of the roll grooving force between the lower and upper grooving rolls.
A further object is the provision of roll grooving apparatus of the foregoing character which is portable, structurally compact, more efficient in operation than roll grooving apparatus heretofore available and which provides improved operator safety as well as the ability to minimize damage to workpieces and/or damage or excessive wear to the grooving rolls and other component parts of the apparatus in the event of problems occurring during the roll grooving operation.