US3861184A

US3861184A - Bending apparatus for forming elbows and the like

Info

Publication number: US3861184A
Application number: US401365A
Authority: US
Inventors: Gary A Knudson
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-09-27
Filing date: 1973-09-27
Publication date: 1975-01-21
Anticipated expiration: 1992-01-21

Abstract

In bending apparatus for forming elbows and the like there is provided a movable ram for advancing the tube and adjacent adjustable crimping dies for crimping the tube. A stepping advance mechanism utilizing a star-like follower wheel and eccentric roller are driven by one rotary drive shaft to step the ram and a cam actuated dual lever arm actuating mechanism is driven by a second rotary drive shaft to reciprocate the crimping dies. A control is used to start the drive shafts and the control automatically stops them when a selected number of crimps and step advances have been made. The crimping dies are adapted for different elbow styles.

Description

United States Patent Knudson l Jan. 2 1, 1975 Primary Examiner-Lowell A. Larson Attorney, Agent, or FirmAncel W. Lewis, Jr.

[57] ABSTRACT In bending apparatus for forming elbows and the like there is provided a movable ram for advancing the tube and adjacent adjustable crimping dies for crimping the tube. A stepping advance mechanism utilizing a star-like follower wheel and eccentric roller are driven by one rotary drive shaft to step the ram and a cam actuated dual lever arm actuating mechanism is driven by a second rotary drive shaft to reciprocate the crimping dies. A control is used to start the drive shafts and the control automatically stops them when a selected number of crimps and step advances have been made. The crimping dies are adapted for different elbow styles,

15 Claims, 11 Drawing Figures PATENTEI] JANZI I975 SHEET 10F 4 Fig. 3

PATENTEU 3,861 ,184

sum 2 or d BENDING APPARATUS FOR FORMING ELBOWS AND THE LIKE BACKGROUND OF THE INVENTION This invention relates generally to bending apparatus for forming tubular products into a desired shape and more particularly to improved apparatus for bending tubes such as selected lengths of downspouts and the like to form elbows.

Metal tubes and particularly metal downspout blanks that are bent along the longitudinal axis are commonly known in the construction trade as elbows. Apparatus for bending downspout blanks to form elbows have heretofore taken a variety of forms but in general require the necessary durability to operate on a relatively intermittent duty cycle for extended time periods as well as a high degree of flexibility for forming different sizes and shapes and bending different types of material. Such apparatus also requires adjustability with quick and efficient changeovers to accomodate the different elbow types.

Accordingly, it is an object of this invention to pro- 'vide improved bending apparatus for forming elbows from sheet metal sections of downspout and the like characterized by a highly durable construction and ease of operation and ready adjustability for producing a variety of elbow styles, dimensions and angles.

Another object of this invention is to provide an improved bending apparatus for forming elbows and the like characterized by having separate and independently operable novel mechanisms for sequentially crimping and advancing a tube section to form an elbow.

A further object of this invention is to provide a novel bending apparatus for forming elbows and the like wherein the crimping dies are readily changed to bend the downspout material either along the minor or major axis of the cross-section thereof.

Yet a further object of this invention is to provide an improved bending apparatus utilizing a novel rack and intermittent duty star-shaped follower wheel and eccentric roller advance mechanism and a fully adjustable cam and spring-biased dual lever arm operated crimping mechanism.

In accordance with the present invention in a preferred form shown there is provided a reciprocally movable outer crimping die set mounted to move normal to the top and both sides of the tube. An automatically controlled drive includes a step advance mechanism driven by one rotary shaft to advance the tube in steps and a cam moved by a second rotary shaft to actuate a spring-biased, dual lever ann assembly moving in a scissor-like action to move the crimping dies in a timed sequence to alternately crimp and step the tube until the desired angle of bend is achieved. A laterally movable block with stepped edges and a manually operable lever selectively controls the extent of rearward movement of the same and thereby establishes the extent of the bend. A motor control having a trip switch stops the crimping and advancing of the tube at a forward limit upon completion of a selected bend.

Other objects, advantages and capabilities of the present invention will become more apparent as the description proceeds taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of an elbow forming machine embodying features of the present invention;

FIG. 2 is a right side elevation view of the machine shown in FIG. 1;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 2 of the machine as viewed from the front;

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 2 showing a portion of the machine as viewed from the top;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 4 showing a portion of the machine as viewed from the right side;

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 5 showing another portion of the machine as viewed from the front;

FIG. 7 is a sectional view taken along lines 77 of FIG. 3 showing a portion of the ram and crimping die assemblies as viewed from the top;

FIG. 8 is a sectional view taken along the-lines 88 of FIG. 3 viewing one side;

FIG. 9-is a sectional view taken along lines 99 of FIG. 3 viewing a portion from the top;

FIG. 10 is a fragmentary perspective view of the apparatus with the external cover panels removed; and

FIG. 11 is a schematic electric circuit showing the control for the drive motor and associated counter.

Referring now to the drawings, in FIGS. 1 and 2 therev is shown an elbow forming machine which, in general, as seen from the outside has a box-shaped housing generally designated by numeral 11 having a removable front cover plate 12 and a side panel 13. The cover plate has a window 14 into which the tube or downspout blank is inserted. The formed elbow 15 being shown in place projects outwardly and upwardly from the window. Side panel 13 has a front face forming a control panel on which there is mounted a start button 16, stop button 17 and count indicator 18. An angle set lever 19 projects through a slot in the front cover plate and affords a manually operable setting for the number of crimps and thereby the degree of bend in the elbow.

In describing the specific embodiment herein chosen for illustrating the present invention, certain terminology relating to relative positions is used for convenience of explanation which will be recognized as being employed only for convenience and having no limiting significance. For example, the terms forward", front, rear and rearward will refer to the directions toward and away from a location occupied by the operator during normal operation of the apparatus; namely, toward and away from the front panel shown in FIG. 1. The terms upper" and lower refer to the illustrated embodiment in its normal position of use. The terms inner" and outer refer to directions toward and away from the geometric center of the apparatus.

The framework for the housing 11 comprises a front plate 21 and rear plate 22 connected to upper side rails 23 and lower side bars 24 with upright front corner bars 25 and upright rear corner bar 26 connected in a boxshaped configuration.

The reciprocally movable ram assembly in the housing has a box-like frame structure with a front end plate 31 and rear end plate 32 held by a top spacer plate 33. A lower rack gear 34 described more fully hereafter is connected to the bottom of the front and rear plates 3] and 32 and serves as a bottom spacer plate. The front and rear plates carry sleeve bearings or journals 35 journaled over laterally spaced

ram support rods

36 and 37 fixedly supported by the front and

rear end plates

21 and 22 of the frame. A forwardly and inwardly tapered tube mandrel 39 is held on the front face of the front end plate 31 by a retainer plate 41 and screw fastener 42 as best seen in FIG. 7. The ram assembly moves the tube forward through a circular opening 21a in the front plate after each crimping operation as described fully hereafter.

The crimping of the tube is effected by a fixedly mounted inner die assembly generally designated A on which the tube is inserted and a reciprocally movable outer die assembly generally designated B.

The inner die assembly A is fixedly supported on a center inner die support rod 45 which is mounted at its rear end in the rear frame end plate 22 and extends through a bearing 46 in the front end plate 31 for added support of the ram assembly. The center rod 45 has a forward neck portion 45a of reduced size. The inner die assembly A includes an inner die plate 51, spacer plate 52, and outer die plate 53 held on the rod portion 450 by an outer retainer plate 54 and bolt fastener 55 which threads into the front end of rod 45. The die

plates

51 and 53 and spacer 52 form an annular groove 56 into which the outer dies described hereinafter extend to form the crimp in the top and both sides of the tube. The inner die assembly is adjustable to change from one style of elbow to another by the removal of top and bottom bolts and rotating the dies through an angle of 90. The difference in style is that the bend in the tube is along the minor axis of the transverse crosssection of the tube instead of the major axis.

The outer die assembly B is comprised of an upper die 61 located above the window and two symmetrically arranged

side dies

62 and 63 disposed on opposite sides of the tube. The upper die 61 is removably fastened by bolts 61a on an upper die holder block 64 that in turn is vertically adjustably movable in relation to a reciprocally movable support plate 65 carried by side support guides 66 on the front of plate 21. The upper die 61 is vertically adjustable by the use of an adjustment block 67 mounted on the plate 65, a central lift screw 68 threading into the holder block 64 and two pressure screws 69 on each side of the lift screw 68 pressing downon block 64. The upper knife die 61 is removed from block 64 to change die styles.

The side dies 61 and 62 are removably mounted on similarly constructed die holders 71 with two screw fasteners 74 that are adjustable by the use of an adjustment block 72, central lift screw 73 and two side pressure screws 74. The die holder 71 is comprised of a front plate 71a, outer end plate 71b and

fasteners

73 and 74 which permit ready removal and replacement of the side dies for different elbow styles.

A lower die block 75 is removably fastened on the front plate 21 with bolt fasteners and this plate is removed when the die styles are changed to a bend along the minor axis of the transverse cross-section of the tube.

The actuating mechanism for the

outer dies

61, 62 and 63 includes a pair of laterally spaced upright

symmetrical lever arms

77 and 78. Each of the lever arms is similarly constructed and has a central pivot member 79 and carry a cam follower roller 81 at the lower end thereof and a cam roller 82 at the upper end thereof. Each cam' roller 82 is slidable in an inclined slot 83 in the movable plate 65 so that as the lever arms pivot inwardly at the top they move the upper crimp die 61 down against the tube. The lower ends of the lever arms have depending extensions 84 and are connected by a tension spring 85 so as to bias the arms to return to an upright at-rest position after they have been spread outwardly.

The side die holders 71 and adjustment blocks 72 are mounted on the associated lever arms by fasteners 74 and above the pivot 79 for the arms. In this way the simultaneous outward movement of the lower end portions of the lever arms out from the upright at-rest position causes the lever arms to move in a scissor-like action to move the upper die down and the side dies in to crimp the tube and the spring returns the arms to the upright at-rest position.

The ram step advance mechanism for the ram assembly comprises a disc-like rotary member 86 carried on a shaft having an axially projecting drive member 87 spaced radially outwardly on the rotary member and engageable with a rotating star-like follower wheel 88 rotatably mounted on a shaft 91 parallel to shaft 90. The wheel 88 has radial arms 89 projecting outwardly at equally spaced intervals so that during a portion of revolution of the rotary member, the star-like follower wheel is advanced one portion of a revolution for each revolution of the rotary member 86. Shaft 91 extends laterally in the housing and carries a pinion gear 92 which meshes with the rack gear 34 and each rotation of the rotary member 86 advances the rack gear one tooth to step the ram in a forward direction in the machine.

The motive power for the machine is an electric motor 93 mounted at the rear of the housing operatively associated with a transmission train including a right angle gear box 94 having an output drive shaft 95 and a sprocket 96. The sprocket 96 is coupled through a chain 97 to a transmission that includes an input shaft 99 with a sprocket 100 and has

output drive shafts

101 and 102 at right angles to one another. The output drive shaft 101 is coupled to shaft 90 carrying rotary member 86 of the ram step advance mechanism and the output shaft 102 carries a gear 103 meshing with a parallel gear 104 on shaft 105 carrying the eccentric cam 106 for moving the lever arms in an outward direction to effect the crimping.

The number of crimps and thereby the angle of bend in the elbow is manually selected by setting the lever 19 in one of a plurality of lateral slots 113 in an angle locator block 114 at the start of the operation. Lever 19 is mounted on the front end of a lever arm 111 pivoted on an intermediate pivot member 112. The lever arm 111 in turn moves a laterally movable slide block 115 using a rear pivot 116 and a supporting cross bar 117. The slide block has a plurality of stepped side edges 118 along the inner side thereof and carries a depending pin 119 associated with each stepped side edge 118. The slide block is carried by two lateral rods 120 extending therethrough. The ram assembly carries an upright stop 121 that will engage one of the steps 118 as it is moved rearwardly to limit the rearward extent of the ram assembly. The positions of the steps are determined by setting the lever in a selected slot 113. The position of the lever 19 shown in a furthest left setting allows the ram to move to a rearmost position and accomplish the maximum number of crimps in the tube.

The motor control circuit is normally contained in the housing 11 and is shown schematically in FIG. 11.

Conventional AC line power is applied to input terminals designated L1 and L2 for the motor 93. A conventional across the line magnetic starter is used which includes normally open line contactors K1 and K2 connected in the power line to terminals L1 and L2, respectively, and an overload protector L in series with the contactor coil Cl and a holding contact HC.

The energization of the contactor coil C1 which causes the motor to run is effected through a series circuit connectedacross terminals L1 and L2 including the overload protector OL, contactor coil Cl, a normally open start button switch SW1 (or normally open rear limit switch SW connected in parallel with switch SW1), normally closed stop button switch SW2 and normally closed forward limit microswitch SW4. Thus when either the start button switch SW1 or the limit switch SW5 is momentarily depressed the contactor coil Cl is energized and either of these switches are biased to immediately return to the open position after depression. Energization of the contactor coil Cl closes holding contactor BC and line contactors K1 and K2 causing the motor to run. The holding circuit includes overload protector OL, coil Cl, holding contactor I-IC, stop switch SW2, and forward limit switch SW4. The motor runs moving the ram foward until limit switch SW4 is opened by being engaged by the ram or the stop button switch SW2 is depressed and opened at which time the holding coil HC is deenergized and line contactors K1 and K2 open.

In the usual sequence of operation, a tube blank is inserted over the ram mandrel of the inner die assembly and the ram is moved rearwardly to the rearmost position. The rear limit switch SW5 has an arm that engages the stepped edge just prior to the stop 121 reaching same. The momentary closing of switch SW5 causes the coil C1 to be energized and contact l-IC closes so that the motor runs to advance the tube forwardly. After each advance or step the crimping dies are actuated by the lever arms. The motor runs until the ram assembly engages switch SW4 to open same deenergizing the coil C1 to stop the motor.

The counter circuit connected across terminals L1 and L2 includes a coil C2 connected in series with a normally open switch SW3 which closes each time the ram comes to the forward position to energize the coil C2 and record one bend of a selected angle on the scale 18.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.

What is claimed is:

1. In bending apparatus for forming elbows and the like from a tube, the combination comprising:

reciprocally movable ram means for a tube,

die means movable in a direction transverse relative to the movement of the ram means to crimp the tube,

a stepping advance mechanism operatively coupled to the ram means, said stepping advance mechanism having a first rotary member driving a rotated second rotary member arranged to rotate through a selected are for each revolution of said first member as the first member is rotated continuously and having linear advance means to convert the rotary movement of said second rotary member to increments of linear motion to step the ram means,

a die actuating mechanism operatively coupled to the die means arranged to convert rotary motion to reciprocal motion to reciprocally actuate the die means in a selected time phase relationship with said stepping advance mechanism to alternately step and crimp the tube in a repetitive cycle,

force applying means including a first rotary drive shaft for driving said first rotary member of said stepping advance mechanism and a second rotary drive shaft for driving said die actuating mechanism, said first and second rotary drive shafts being rotated simultaneously; and

control means to auomatically stop the first and second rotary drive shafts of said force applying means when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

2. In bending apparatus as set forth in claim 1 wherein said ram means includes box-like frame structure inclusive of front and rear plates held apart by top and bottom spacer structure, said plates being slidably mounted on a pair of laterally spaced support rods and an inner mandrel on the front plate of the frame structure on which the leading end of the tube is placed.

3. In bending apparatus as set forth in claim -1 wherein said die means includes an stationary inner die assembly on which the tube is placed and an outer die assembly having top crimp die and a pair of opposed outer side crimp dies mounted about the inner die to move inwardly against the tube on the inner die to crimp three sides of the tube.

4. In bending apparatus as set forth in claim 3 wherein said inner die assembly has a support rod and a set of internal die plates removably mounted on the end of the rod and arranged to mount thereon at one of two angular positions.

5. In bending apparatus as set forth in claim 3 wherein said outer top and side dies are removably mounted in adjustable die holders, said outer top and side dies having individual adjustments relative to the inner die assembly.

6. In bending apparatus as set forth in claim 3 including a reciprocally movable top plate on which the top crimp die is carried and wherein said die actuating mechanism includes a pair of upright, symmetrical lever arms on opposite sides of the outer side crimp dies, each of said lever arms being pivoted between the upper and lower end portions thereof and having an upper cam roller above the associated pivot arranged to impart downward motion to the top crimp die as they are moved in associated inclined slots in said movable top plate to impart a vertical downward force to the top die as the upper end portions of the lever arms are pivoted inwardly and cam means operatively associated with the second rotary shaft to move the lower end portions of the lever arms in an in-and-out reciprocal movement in a continuous cycle.

7. In bending apparatus as set forth in claim 1 wherein said first rotary member has an axially extending eccentric drive roller, eccentrically arranged in relation to axis of rotation of the first rotary member and said second rotary member is in the form of a starslike follower wheel having radial arms projecting outwardly at circumferentially spaced intervals with spaces between the arms sized to receive the eccentric drive rolwherein said force applying means includes an electric motor and said control means includes a magnetic control for selectively starting and stopping the motor and an electric switch operatively associated with the magnetic control tripped each time the ram means reaches a selected forward position to automatically stop the motor.

8. In bending apparatus as set forth in claim 1 including an angle control having manually settable lever and an associated adjustable stop means to set the rearmost position of the ram means to select the number of crimps for the tube.

9. In bending apparatus as set forth in claim 1 wherein said force applying means includes a motor and a gear transmission with a single input shaft coupled to the motor and two output drive shafts arranged at right angles to one another.

10. In bending apparatus as set forth in claim 1 11. In bending apparatus as set forth in claim 10 12. In bending apparatus as set forth in claim 1 including means to count each time the ram means moves to the forward extended position.

13. In bending apparatus for forming elbows and the like from a tube, the combination comprising:

die means to crimp a tube including an inner die assembly and an outer die assembly,

reciprocally movable ram means for the tube having a frame structure slidably mounted on spaced support rods, said frame structure including a front end plate and a rear end plate having a rack gear along a lower portion thereof and an inner mandrel on the front end plate on which the leading end of the tube is placed for the movement of the tube by the ram means,

a stationary center rod extending through the front and rear end plates and inner mandrel, said center rod supporting the stationary inner die assembly at the front end thereof,

a stepping advance mechanism for the ram means including a first rotary member having an axially extending drive member, eccentrically arranged in relation to the axis of rotation of the rotary member and an intermittently rotated second rotary member in the form of a star-like follower wheel having a plurality of radial arms projecting outwardly at circumferentially spaced intervals with spaces between the arms sized to receive the eccentric drive member and successively engaging one of the radial arms to advance the follower wheel one arm for each revolution of the rotary "We 6 a pinion gear rotatlng con ointly w1th the follower wheel meshing with the rack gear on the ram means for stepping the rack gear a selected linear distance for each revolution of the first rotary member,

a die actuating mechanism operatively coupled to the die means arranged to convert rotary motion to reciprocal motion to reciprocally actuate the die means in a selected time phase relationship with said stepping advance mechanism to phase relationship with said stepping advance mechanism to alternately step and crimp the tube in a repetitive cycle,

a drive for the die means and ram means including a first rotary drive shaft for driving the stepping advance mechanism and a second rotary drive shaft for driving said die actuating mechanism; and,

control means to automatically stop the drive means when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

14. In bending apparatus forming elbows and the like from a tube, the combination comprising:

ram means for a tube,

co-operative outer and inner crimp die assemblies including an upper crimp die mounted above the tube on a reciprocally movable top plate having a pair of symmetrical, inclined slots and two symmetrical outer side crimp dies on opposite sides of the tube,

a pair of generally upright lever arms each carrying one of the outer side dies and pivoted between the upper and lower end portions thereof at spaced pivot points in a scissor-like action,

each lever arm having an upper cam roller disposed in an inclined slot in the top plate to urge the top plate downwardly when the upper end portions of the lever arms are urged toward each other,

each lever arm having a cam follower roller at a lower end portion,

an eccentric drive cam driven against said lower cam followers to move the lower end portions of the lever arms outwardly away from one another,

said lever arms having biasing means at the lower end portions to draw the lower end portions toward one another to an upright at-rest position,

a stepping advance mechanism operatively coupled to the ram means arranged to convert rotary motion to stepped linear motion to step the ram means,

force applying means including a first rotary drive shaft rotating said eccentric drive cam and a second rotary shaft operatively coupled to said stepping advance mechanism to successively advance the tube a pre-selected distance each time after the tube has been crimped by said dies; and

control means to stop the force applying means when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

15. In bending apparatus for forming elbows and the like from a downspout tube, the combination comprismg:

a support frame having a front end plate and rear end plate with a hole in the front end plate through which a tube is inserted,

reciprocally movable ram means in the support frame for the tube including a frame structure slidably mounted on spaced support rods, said frame structure including a front plate and a rear plate having a rack gear along the lower portion thereof and an inner stationary mandrel on the front plate on which the leading end of the tube is placed for the movement of the tube by the ram means,

a center rod extending through the front and rear plates and inner mandrel supporting the inner die assembly in the hole of the front end plate at the front end thereof,

each lever arm having a cam follower roller at a lower end portion,

an eccentric drive cam driven against said lower cam follower to move the lower end portions of the lever arms outwardly away from one another.

a stepping advance mechanism for the ram means including a first rotary member having an axially extending drive member, eccentrically arranged in relation to the axis of rotation of the rotary member and an intermittently rotated second rotary member in the form of a star-like follower wheel having radial arms projecting outwardly at circumferentially spaced intervals with spaces between the arms sized to receive the eccentric drive member and engaging one of the radial arms to advance the follower wheel one arm for each revolution of the rotary member,

a pinion gear rotating conjointly with the follower wheel and meshing with the rack gear for stepping the ram means a selected linear distance for each revolution of the first rotary member,

a drive for the die means and ram means including a first rotary drive shaft for driving the stepping advance mechanism and a second rotary drive shaft for driving said die actuating mechanism; and

control means to automatically stop the drive when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

Claims

1. In bending apparatus for forming elbows and the like from a tube, the combination comprising: reciprocally movable ram means for a tube, die means movable in a direction transverse relative to the movement of the ram means to crimp the tube, a stepping advance mechanism operatively coupled to the ram means, said stepping advance mechanism having a first rotary member driving a rotated second rotary member arranged to rotate through a selected arc for each revolution of said first member as the first member is rotated continuously and having linear advance means to convert the rotary movement of said second rotary member to increments of linear motion to step the ram means, a die actuating mechanism operatively coupled to the die means arranged to convert rotary motion to reciprocal motion to reciprocally actuate the die means in a selected time phase relationship with said stepping advance mechanism to alternately step and crimp the tube in a repetitive cycle, force applying means including a first rotary drive shaft for driving said first rotary member of said stepping advance mechanism and a second rotary drive shaft for driving said die actuating mechanism, said first and second rotary drive shafts being rotated simultaneously; and control means to auomatically stop the first and second rotary drive shafts of said force applying means when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

3. In bending apparatus as set forth in claim 1 wherein said die means includes an stationary inner die assembly on which the tube is placed and an outer die assembly having top crimp die and a pair of opposed outer side crimp dies mounted about the inner die to move inwardly against the tube on the inner die to crimp three sides of the tube.

7. In bending apparatus as set forth in claim 1 wherein said first rotary member has an axially extending eccentric drive roller, eccentrically arranged in relation to axis of rotation of the first rotary member and said second rotary member is in the form of a star-like follower wheel having radial arms projecting outwardly at circumferentially spaced intervals with spaces between the arms sized to receive the eccentric drive roller and engaging one of the radial arms to advance the follower wheel one arm for each revolution of the rotary member, the linear advance means having a rack gear in a driven relation with a pinion gear rotating conjointly with the follower wheel for stepping the rack gear a selected linear distance for each revolution of the first rotary member.

10. In bending apparatus as set forth in claim 1 wherein said force applying means includes an electric motor and said control means includes a magnetic control for selectively starting and stopping the motor and an electric switch operatively associated with the magnetic control tripped each time the ram means reaches a selected forward position to automatically stop the motor.

11. In bending apparatus as set forth in claim 10 wherein said control includes a second electric switch operatively associated with the magnetic control and tripped each time the ram means reaches a preselected rear retracted position to start the motor to advance the ram means.

12. In bending apparatus as set forth in claim 1 including means to count each time the ram means moves to the forward extended position.

13. In bending apparatus for forming elbows and the like from a tube, the combination comprising: die means to crimp a tube including an inner die assembly and an outer die assembly, reciprocally movable ram means for the tube having a frame structure slidably mounted on spaced support rods, said frame structure including a front end plate and a rear end plate having a rack gear along a lower portion thereof and an inner mandrel on the front end plate on which the leading end of the tube is placed for the movement of the tube by the ram means, a stationary center rod extending through the front and rear end plates and inner mandrel, said center rod supporting the stationary inner die assembly at the front end thereof, a stepping advance mechanism for the ram means including a first rotary member having an axially extending drive member, eccentrically arranged in relation to the axis of rotation of the rotary member and an intermittently rotated second rotary member in the form of a star-like follower wheel having a plurAlity of radial arms projecting outwardly at circumferentially spaced intervals with spaces between the arms sized to receive the eccentric drive member and successively engaging one of the radial arms to advance the follower wheel one arm for each revolution of the rotary member, a pinion gear rotating conjointly with the follower wheel meshing with the rack gear on the ram means for stepping the rack gear a selected linear distance for each revolution of the first rotary member, a die actuating mechanism operatively coupled to the die means arranged to convert rotary motion to reciprocal motion to reciprocally actuate the die means in a selected time phase relationship with said stepping advance mechanism to phase relationship with said stepping advance mechanism to alternately step and crimp the tube in a repetitive cycle, a drive for the die means and ram means including a first rotary drive shaft for driving the stepping advance mechanism and a second rotary drive shaft for driving said die actuating mechanism; and, control means to automatically stop the drive means when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

14. In bending apparatus forming elbows and the like from a tube, the combination comprising: ram means for a tube, co-operative outer and inner crimp die assemblies including an upper crimp die mounted above the tube on a reciprocally movable top plate having a pair of symmetrical, inclined slots and two symmetrical outer side crimp dies on opposite sides of the tube, a pair of generally upright lever arms each carrying one of the outer side dies and pivoted between the upper and lower end portions thereof at spaced pivot points in a scissor-like action, each lever arm having an upper cam roller disposed in an inclined slot in the top plate to urge the top plate downwardly when the upper end portions of the lever arms are urged toward each other, each lever arm having a cam follower roller at a lower end portion, an eccentric drive cam driven against said lower cam followers to move the lower end portions of the lever arms outwardly away from one another, said lever arms having biasing means at the lower end portions to draw the lower end portions toward one another to an upright at-rest position, a stepping advance mechanism operatively coupled to the ram means arranged to convert rotary motion to stepped linear motion to step the ram means, force applying means including a first rotary drive shaft rotating said eccentric drive cam and a second rotary shaft operatively coupled to said stepping advance mechanism to successively advance the tube a pre-selected distance each time after the tube has been crimped by said dies; and control means to stop the force applying means when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.

15. In bending apparatus for forming elbows and the like from a downspout tube, the combination comprising: a support frame having a front end plate and rear end plate with a hole in the front end plate through which a tube is inserted, reciprocally movable ram means in the support frame for the tube including a frame structure slidably mounted on spaced support rods, said frame structure including a front plate and a rear plate having a rack gear along the lower portion thereof and an inner stationary mandrel on the front plate on which the leading end of the tube is placed for the movement of the tube by the ram means, co-operative outer and inner crimp die assemblies including an upper crimp die mounted above the tube on a reciprocally movable top plate having a pair of symmetrical, inclined slots and two symmetrical outer side crimp dies on opposite sides of the tube, a center rod extending through the front and rear plates and inner mandrel supporting the inner die assembly in the hole of the front end plate at tHe front end thereof, a pair of generally upright lever arms each carrying one of the outer side dies and pivoted between the upper and lower end portions thereof at spaced pivot points in a scissor-like action, each lever arm having an upper cam roller disposed in an inclined slot in the top plate to urge the top plate downwardly when the upper end portions of the lever arms are urged toward each other, each lever arm having a cam follower roller at a lower end portion, an eccentric drive cam driven against said lower cam follower to move the lower end portions of the lever arms outwardly away from one another. said lever arms having biasing means at the lower end portions to draw the lower end portions toward one another to an upright at-rest position, a stepping advance mechanism for the ram means including a first rotary member having an axially extending drive member, eccentrically arranged in relation to the axis of rotation of the rotary member and an intermittently rotated second rotary member in the form of a star-like follower wheel having radial arms projecting outwardly at circumferentially spaced intervals with spaces between the arms sized to receive the eccentric drive member and engaging one of the radial arms to advance the follower wheel one arm for each revolution of the rotary member, a pinion gear rotating conjointly with the follower wheel and meshing with the rack gear for stepping the ram means a selected linear distance for each revolution of the first rotary member, a drive for the die means and ram means including a first rotary drive shaft for driving the stepping advance mechanism and a second rotary drive shaft for driving said die actuating mechanism; and control means to automatically stop the drive when the tube has been crimped and advanced a preselected number of times to effect the desired angle in the tube.