Portable pipe-bending minimachine able to be manually - or motor-controlled and including an engaging/automatic disengaging device

Abstract: Portable manually or motor-controlled pipe-bending minimachine which, in spite of its small size as compared with similar machines, is easier and handier to operate on site for the bending of pipes ranging 4 mm to 22 mm in diameter. The minimachine is provided with a reverse gear (53) and an intermediary device (50) built in the minimachine main body (11) which allows the engagement and automatic disengagement of the gear drive (40) transmitting rotary motion to the matrix-carrying shaft. Both the motor (90) and the manual control lever assembly (60) allowing alternate control of consecutive angular movements of matrix (16), can be easily and quickly mounted on the main body; and the countermatrix (24) is an interchangeable device to be mounted on a special support (20) allowing it to be appropriately positioned at the start of a bending operation.

Description: The present invention relates to the field of the pipe-bending machines. More particularly, the present invention relates to a portable rotary matrix and countermatrix manually or motor operated pipe-bending machine. Prior art in the bending of small and medium diametre pipes mainly intended for use in sanitary plumbing, has proposed and constructed several types of portable pipe-bending machines or apparatuses, which are small both in size and weight, so that they can be used on site, due to easier and handier operation, considering that such a type of machines are widely used and also offer greater advantages lying in the lower cost of both the machines and their application, particularly in said plumbing systems. The Applicant has previously suggested and costructed several portable pipe-bending machines to improve both the working conditions and the results, making use of the advanced techniques that have been developed in the field of pipe bending and increasingly striving to satisfy the usefulness and/or necessity requirement of producing a bent pipe free from deformations, breaks, or cracks, which might even become apparent some time later, after the bent pipe has been produced and installed, also in the event the material, diametre, and thickness of the pipe are more sensitive to stretching stresses during the bending operation. EP-A-0 350 457 (State of the Art according to Art. 54(3) EPC) specified how the technique employed in prior art pipe-bending machines had been improved by two major innovations: the machine ability to operate at three different speeds; and the use of an auxiliary device which may either be separate and designed to be connected to the pipe-bending machine, or be built in the main body, and which consists of a special clutch having the function of engaging/disengaging the gear drive so as to either actuate the main matrix-carrying shaft for the pipe bending operation to be carried out, or automatically disengage the main matrix-carrying shaft. As the importance of said two features was proved by practical experiments, they have been taken into consideration for more appropriate use in the pipe-bending machine this invention relates to, with the aim of designing a portable pipe-bending machine best suited to bend pipes in a little narrower range of diameters, namely 8 to 42 mm diameters, than the one the Applicant production has been devoted to so far, and which includes other features deserving particular attention, in addition to those just mentioned. This aim is achieved by a pipe-bending machine according to claim 1. The features of the new pipe-bending machine according to this invention have been summarized in the introduction and can be better interpreted by the skilled in the art if the following description of an embodiment of the machine is read attentively, making reference to the accompanying drawings in which: Fig. 1 is a schematic top view of the boxlike main body of a pipe-bending machine according to this invention, wherein thicker and dashed lines represent the bending member or matrix in a position ready for the bending operation to be started, and the countermatrix to be put in the proper position for starting such operation; Fig. 2 is a schematic top view of the special support on which is mounted the countermatrix suited to the pipe to be bent; Fig. 3 is a schematic view of the right-hand side of support shown in Fig. 2; Fig. 4 is a schematic top view of the gear drive intended for use in this new type of machine, with the component members built in the lower part of the main body as may be viewed if the top part is removed; the figure includes also the motor and associated pinion gear controlling the gear drive, shown in the envisaged mounting position; Fig. 5 is a schematic top view of the machine according to Fig. 1, with the pipe and the countermatrix shown in the position ready for the bending operation to be started and the manual control device mounted on one side of the main body; Fig. 6 is a vertical sectional view taken on the mid plane of a ratchet wheel actuated by a lever and pawl to impart consecutive intermittent movements to the gear drive and corresponding angular movements of the matrix; Fig. 7 is a schematic longitudinal elevation view of the manual control lever device, shown in the inoperative position; Fig. 8 is a sectional view taken on line 8-8 of fig. 7; Fig. 9 is a schematic longitudinal elevation view of the manual control lever device, shown in the operative position; Fig. 10 is a sectional view taken on line 10-10 of fig. 9. The following innovative features deserve special attention: the main body; the gear drive; the matrix-countermatrix combination; the gear drive motor control; the gear drive manual control; which will be described hereinafter as an example of embodiment. Main body Like other pipe-bending machines designed by the Applicant, the main body of this invention is an elongated carrying structure (11) of small size and relatively little weight as required to better meet the portability and operability requirements. According to this pipe-bending machine identified by number (10), the lower part (12) of main body (11) contains a gear drive (40) and its fore face (14) is designed and preset to mount either a motor (90) integral with it, if the gear drive (40) is to be motor-driven, or a special support (60) for manual control, as will be better explained later. As shown in Figs. 1 and 5, both the offset hexagon head (15) of the main shaft on which the matrix (16) is to be mounted, and the pin (22) of countermatrix (24) special support (20), project from the top surface of main body (11). On said top surface is mounted a piece (28) with mounting plate (29), which is used as the horizontal axis fulcrum of a forklike lever (71) allowing manual control of gear drive (40). Gear drive The gear drive identified by number (40) should be considered as an improvement distinguishing this machine from those previously proposed and claimed, although it includes some elements that have been described in other applications. The gear drive (40) substantially serves the following purposes: 1) drive the main shaft carrying the matrix (16) at different speeds of rotation of the matrix either for pipe bending purposes, or for returning to the starting position, regardless of whether the machine operates under motor or manual control; 2) automatically disengage the main matrix-carrying shaft when the amount of resisting torque resulting from the main shaft operation during the time a pipe is being bent, exceeds that of the driving torque applied to carry out the bending operation, and in that case the jaws of a clutch will be disengaged from each other, bearing in mind, however, that the amount of torque can be externally preset; 3) facilitate the matrix-carrying shaft reverse rotation by the appropriate meshing of gear drive gear wheels, which can be easily accomplished by the operator; 4) allow the operator to mount either the motor or the manual control device on the pipe-bending machine main body, in a relatively easy and handy manner; 5) considering the peculiar features of the gear drive, as far as the main shaft rotation is concerned, it may be interesting to note that said shaft can be utilized, if required, in tool-carrying applications for such purposes as for instance; srewing/unscrewing bolts, nuts, sleeves, pipes, etc. threading or tapping; pipe cutting and shearing, with the shaping to be adapted to appropriate coupling with the tool. The following component parts of the gear drive (40) described herein are built in the lower part (12) of boxlike main body (11): a driving section comprising gear wheels mounted on a single longitudinal shaft (95), a driven section comprising gear wheels mounted on a second longitudinal shaft (43), parallel with shaft (95), which mounts also a coaxial auxiliary device including an engaging/disengaging clutch (48, 46). The jaw (48) rotates together with shaft (43), is able to slide because it is mounted on key (51), and is urged by a compression coil spring (50) to engage with jaw (46) whereas the jaw (46) can only rotate on the longitudinal shaft together with worm gear (42) integrally formed with it, because a guide ring, or the like (47) determines its position on shaft (43). Shaft (43) carries a pair of coaxial, integrally mounted, reverse gear wheels (54, 55) which are locked to said shaft by means of long key (52), but can be slided along shaft (43) under the control of a lever (only represented by longitudinal line (46)), pivoting on a fixed pin (58), and whose inner arm is provided, at one end, with a roll (56) intended to favour the controlled sliding of the reverse gear assembly along the shaft and hence the meshing with the other gear wheels used for reversing purposes. According to the embodiment shown in Fig. 4, and referring to the above description, shaft (95) carries a gear wheel (96) meshing with gear wheel (54) of reverse gear assembly (53), and a gear wheel (97) which is constantly in mesh with intermediate gear (98) which will mesh with gear wheel (55) of the reverse gear assembly when the operator moves lever (56) to slide the reverse gear assembly along shaft (43), thus throwing gear wheel (54) out of mesh with gear wheel (96). The worm gear (42) meshes with helical gear wheel (41) to transmit rotary motion to the main shaft whose offset hexagon head mounts, as previously mentioned, the matrix (16) to be controlled. It is obvious that control of the matrix is obtained when jaws (48, 46) are engaged with each other as shown in Fig. 4, because the worm gear (42) will then rotate together with shaft (43) which will, in turn, be driven by either one of gear wheels (96, 97) depending on the position to which either one of mating gear wheels of reverse gear assembly (53) has been set. It should be specified that both the motor and manual controls of the pipe-bending machine (10) according to the embodiment described herein, are obtained by rotating shaft (95) and hence gear wheels (94, 97, 96) mounted on it, as will be better explained later. Matrix-countermatrix combination The bending member or matrix (16) schematically shown in Figs. 1 and 5 illustrating this example, is of a substantially conventional type, has a halfround groove to bend pipes up to 180°, and the centerlines of both its own groove and opposed groove (24') of countermatrix (24) are preferably lying constantly on the same plane although both grooves will necessarily change in size depending on the diameter of the pipe to be bent. The major innovative feature is the special support (20) on which the countermatrix (24) is to be mounted. It can be seen from Figs. 1 - 3 that the support (20) substantially consists of a "C" piece whose flat parallel arms (21, 21') are an adequate distance apart, and extend from a solid piece provided with pin (22) whose axis is normal to the planes of said arms, and to be fastened to the top surface of boxlike main body (11) of the machine (10). Pin (22) acts as a pivot for said support (20) so that the latter can freely rotate on it. The space between the inner parallel faces of arms (21, 21') houses the portion of countermatrix projecting normal to groove (24') and having a hole for pin (23) which allows some angular movement of countermatrix (24), said angular movement being restricted by projection (26) diverging nearly radially from said projecting portion and restricting the free rotation of countermatrix on pivot (23) by striking against a pin (27) located between arms (21, 21') of support (20). According to Figs. 1 and 5, the free rotation of countermatrix (24) support (20) is restricted too by a pin (25) projecting from the top surface of main body (11) to be struck against by the lower arm (21') of the support. The features in both construction and operation of support (20) and associated countermatrix (24) will be further clarified here below to draw attention to the innovative features: the support is constructed with predetermined shape and dimensions and allows any countermatrix (24) selected out of the available set as suitable to bend a pipe of a given diameter, to be mounted on it and operate; the distance x (Figs. 2 and 3) from the centerline of groove (24') of countermatrix (24), to the countermatrix axis of rotation, changes according to the countermatrix selected for operation; the ability of support (20) to turn on pivot (22) makes it easier to mount the countermatrix (24), as well as to make its groove (24') to initially rest against the tube p to be bent while the matrix is in the starting position for the subsequent bending operation; during said initial stage, the edge of lower arm (21') of support (20) is in a position a little distance away from the banking pin (25), and that distance will be reduced to zero when at the start of a bending operation, the matrix drags the countermatrix to the final position whereby the opposed grooves can interact in the most effective manner, which proves the usefulness and advantage of the special shape of the countermatrix groove to obtain the desired pipe bending. The advantages that a user can draw from the pipe-bending machine (10) according to this invention are further substantiated by the fact that in this new type of pipe-bending machine (10) the shape of countermatrix (24) groove (24') is according to the Italian Patent No. 1.147.601 granted to the Applicant. Gear drive motor control In this embodiment of the invention, the motor (90) has been assumed to be fastened to wall (14) of the machine main body (11), through a supporting plate and pins and/or bolts driven in a direction parallel to the axes of shafts (43, 95) of the gear drive, as shown by dashed lines. The motor may be of the same type as used by the Applicant on other pipe bending machines, such as the one, for instance, mentioned in the Italian Patent No. 1.147.601 granted to the Applicant. It should, however, be specified, as a particularly important feature of this invention, that in the pipe-bending machine (10) this invention is related to, the motor carrying structure can be used also as a handle to be held and controlled by one hand, and that the motor shaft mounts a pinion gear (93) in mesh with gear wheel (94) which is one of those mounted on previously described shaft (95), the ratio between pinion (93) and gear wheel (94) being such as to provide a first amount of speed reduction to which, according to the schematic view of Fig. 4, is added that provided by meshed gear wheels (96, 54), and the final one provided by the meshed worm gear (42) and helical gear (41), in order to obtain the desired rotation speed of matrix-carrying shaft (15). Electric power is applied to the motor (90) through a cord (92). A conventional switch, of for instance the toggle type (not shown), is a handy means allowing the operator to start the motor and manually control the machine (10) by one hand. Gear drive manual control Figures 5 and 6 schematically show the main details of the component parts of a device (60) used to actuate the gear drive previously described with reference to Fig. 4. As stated in the introduction, such a manual control device must be easy to mount on main body (11) of pipe-bending machine (10) and must control the rotation of shaft (95) in such a way as to drive in either the forward or reverse direction the matrix (16), in a manner similar to that previously described concerning the motor control. The possible embodiment schematically shown in Figs. 5 and 6, and with added details in Figs. 7 and 8, makes use of a device (60) which can be fastened to the fore face (14) of main body (11) for instance by means of pin (68) and fixing screw (69), since it is shaped like a channel section consisting of two flat parallel surfaces (60a, 60b) formed into a single unit and separated by a spacer (60c) to provide room for a ratchet wheel (61) whose axis of rotation is normal to said surfaces. A "C" projection (63), integral with said channel section, has a dovetail bottom wall for a hollow piece (64), shaped to match the dovetail, to slide in the vertical direction, and whose recess houses a pawl (67') that engages the teeth of said ratchet wheel. The "C" projection (63) is provided with opposed projecting pins (65) housed in slots (66) of the arms (72) of a forklike lever (71) to allow said pawl (67') to engage the teeth of the ratchet wheel (61) and to impart repeated consecutive intermittent angular movements to the ratchet wheel itself, and consequently to matrix (16) through said gear drive (40). Said forklike lever (71) is provided intended to be manually alternately moved, a spring (not shown) being located between the lever (71) and the stationary part of the machine (10) so as to make it still easier to operate the machine by one hand and in any position during the bending operation. When the machine is not in operation, the external arm (73) of lever (71) can be locked to the opposite guide support (74) by means, for instance, of a ring hook (75). The ratchet wheel (61) transmits its motion to the shaft (95) by being endowed with a hub (62) that mates with a blind hole provided at the external end of the shaft (95) itself.

Claims: A portable rotary matrix and countermatrix pipe-bending machine (10) comprising a boxlike main body (11) which incorporates a gear drive (40) for either manual or motor drive of the matrix-carrying shaft, said shaft being coupled with an engaging/disengaging clutch (48, 49) that engages and automatically disengages said shaft from the drive gear (40) when the amount of resisting torque on the shaft during the bending operation exceeds that of the driving torque applied to carry out the bending operation, and with a reverse gear system (53) which reverses the rotation of the matrix-carrying shaft in both the manual and motor drive modes, and in which the rotary matrix (16) has a halfround groove and the interchangeable countermatrix (24) is mounted on a revolving support (20), wherein: the gear drive (40) consists of two longitudinal parallel shafts (95, 43), the first one of which is used to accomplish motor drive by means of a motor (90) and associated pinion gear (93) or to accomplish manual drive by means of a manual control device assembly (60) which can be fastened to the front face (14) of the main body (11), said manual control assembly (60) comprising a lever (71) for imparting a consecutive intermittent angular movements to a ratchet wheel (61) coupled to one end of said shaft (95), both drive devices transmitting rotary motion to said shaft (95) along with gear wheels (95, 96, 97) mounted along its length, said shaft (43) being rotated by said shaft (95) by either one of two gear wheels (54, 55) mounted thereon to form said reverse gear system (53) and locked to it by key (52), one (54) of said gear wheels directly meshing with the respective gear wheel (96) of the shaft (95), whereas the other gear wheel (55) of said reverse gear system (53) meshes indirectly with the respective gear wheel (97) of said shaft (95) through an intermediate gear (98) to reverse the rotation of said shaft (43) and thus the direction of pipe travel, said shaft (43) being provided with a worm gear (42) meshing with a helical gear (41) provided on the matrix-carrying shaft, said worm gear (42) forming a single unit with said engaging/disengaging clutch (47, 48); said reverse gear system (53) being able to slide along said shaft (43) by means of a longitudinal axis lever (56) pivoted on an end pin (58) provided on the main body (11) and by means of an end pin (57) which slides in said key (52), and wherein the countermatrix holder is located and revolves in the plane of rotation of the matrix (16) between two flat parallel arms (21, 21') of a support (20) mounted and revolving in turn in the plane of rotation of the matrix (16) on a pin (22) projecting from the top surface of said main body (11), said support (20) allowing the mounting of said interchangeable countermatrix (24) and the positioning of its groove (24') at the start of a bending operation, the angular movement of said countermatrix being restricted by a projection (26) thereof striking against a pin (27) provided on said support (20), while the angular movement of said support (20) is restricted by a pin (25) projecting from the top surface of the main body (11). The portable rotary matrix and countermatrix pipe-bending machine according to claim 1, characterized in that the manual control device assembly (60) consists of a channel section support fastened to the fore face (14) of said main body (11) through two parallel surfaces (60a, 60b) and providing room for the mounting between said surfaces of said ratchet wheel (61) whose hub (62) is shaped to be inserted into a mating blind hole provided at the external end of said shaft (95) of said gear drive (40), said channel section support being provided with a top projection (63) having a dovetail bottom wall in which a piece (64) slides in the recess whereof a pawl (67') is pivoted, and is provided with opposed projecting pins (65) housed in slots (66) of the arms (72) of a forklike lever (71), to allow said pawl (67') to engage the teeth of said ratchet wheel (61) to impart consecutive intermittent angular movements to the ratchet wheel (61) and consequently to the matrix (16) through the gear drive (40); said alternate angular movement of said lever (71) being favoured by the use of a spring located between the external arm (73) of said lever and its guide support (74), the latter being so shaped as to allow the machine itself (10) to be controlled by one hand and being provided with a ring (75) used for hooking said external arm (73) and lock the lever (71) in position when the machine (10) is not in operation.

Inventors: CAPORUSSO ALESSANDRO, CAPORUSSO MARIO, CAPORUSSO, ALESSANDRO, CAPORUSSO, MARIO
Applicants: LIRI COSTRUZIONI MECC, C.M.L. COSTRUZIONI MECCANICHE LIRI S.R.L.
Application year: 1989
Main classification: B21D7
IPC codes: B21D7