U-Bolt bending machine

Abstract

A bending machine for bending elongate metal stock into curved configurations. Two adjustably fixed spaced dies receive the stock thereagainst while a movable die moves between the fixed dies causing the metal to be bent into a curvature of up to 180.degree..

Description

THE PRIOR ART

The U.S. Pat. Nos. to Kroetch 3,724,256; Denninger 3,610,019; Hutch 3,429,157; and, Shaw Jr. 3,260,091 are examples of the known prior art.

BACKGROUND OF THE INVENTION

Bending machines for fabricating U-bolts and the like are known as examplified by the above referred to prior art patents. It is often desirable for small machine shops and fabrication shops to be able to bend tubular stock into a radius of curvature up to 180.degree., as for example the making of a U-bolt. Such a desirable expedient avoids carrying a large and expensive inventory, but also enables the most optimum choice of material since the exact desired part can be fabricated at once, thereby effecting a savings in both time and money.

It is desirable that such a machine be low in cost, simple to operate, and efficient in operation.

SUMMARY OF THE INVENTION

A bending machine for bending elongated metal stock into a curve having a radius of curvature up to 180.degree.. Two pivoted arms carry fixed dies at the pivoted end thereof, with the dies being adjustably disposed in spaced relation to one another. The arms are supported from a table.

A movable die is mounted to a power member by means of a mandrel with the mandrel being brought through a slot in the table so that the table can form the main support structure for all of the apparatus.

The movable die is forced to pass between the fixed dies, thereby causing any stock placed therebetween to be bent according to the configuration of the movable die and the extent of relative movement between the fixed and movable dies.

Accordingly, a primary object of this invention is the provision of a bending machine for forcing elongated metal stock into a non-linear configuration;

Another object of the invention is to provide a bending machine for use in fabricating U-bolts from elongated metal stock.

A further object of this invention is to provide a bending machine in which spaced fixed dies and a movable die cooperate together in a novel manner to provide a U-bolt in an unexpected manner.

A still further object of this invention is to provide a bending machine which is simple to operate, low in initial cost, safe in operation, and efficient in design.

The above objects are attained in accordance with the present invention by the provision of a combination of elements which are fabricated in a manner substantially as described in the above abstract and summary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of apparatus made in accordance with the present invention;

FIG. 2 is a diagrammatical, part schematical representation of an important principal of operation of the present invention;

FIG. 3 is a broken, part cross-sectional representation which sets forth some of the details of the invention;

FIG. 4 is a longitudinal, part cross-sectional view which sets forth some important details of the present invention, with some parts being broken away to more clearly illustrate what lies therebeyond;

FIG. 5 is a top plan view of apparatus disclosed in the foregoing figures, with parts being broken away therefrom to disclose important aspects of the invention;

FIG. 6 is an end view of the apparatus disclosed in FIG. 5;

FIG. 7 is an enlarged detailed top view of part of the apparatus disclosed in FIGS. 5 and 6;

FIG. 8 is an enlarged detail taken along line 8--8 of FIG. 7;

FIG. 9 is a bottom view looking along the arrows indicated by line 9--9 of FIG. 8;

FIG. 10 is a side elevational view of another form of the invention; and,

FIG. 11 is a bottom view taken along line 11--11 of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Throughout the figures of the drawing, wherever possible, like or similar numerals will refer to like or similar elements thereof. In the figures of the drawing there is disclosed a U-bolt bending machine 10 comprised of a reinforced table 12, a bending die 14 which moves relative to table 12, a roller die 16 spaced from a second roller die 17 with the dies being adjustably mounted in fixed relation respective to one another and to the table. A longitudinally extending marginal portion of a rod having the marginal opposed ends thereof threaded and placed in the illustrated manner of FIG. 2a so that opposed ends L1, L2 of the rod are bent toward one another as axis C1 and C2 move through one another.

As particularly seen in FIG. 2a, the roller dies 16 and 17 are disposed along axes C1 with the threaded rod 18 having a marginal portion 19 abuttingly engaged with an outer peripheral wall surface of the roller dies. The rod also engages a flat leading edge portion 15 of the central die 14.

In FIG. 2b axis C1 and C2 remain parallel and are forced to move toward one another thereby breaking the central marginal portion 19 of the rod into the beginning of a radius of curvature seen illustrated at 19' in FIG. 2b and 119 in FIG. 2c.

As seen in FIG. 3, a mandrel 20 has a lower end portion 22 and an opposite upper end portion, the latter being provided with a vertical index key 23 and the former being provided with a horizontal index key 24. As seen in FIG. 7, a keyway 26 is cut into the movable die. The outer peripheral surface 27 of the movable die ordinarily circumferentially extends in a manner as indicated by the dot-dashed area 27'. The leading edge of the die is provided with a vertically disposed face 28 for initially engaging stock 19. Numeral 29 indicates the bending configuration of stock 19 in the absence of face 28 being formed into the leading edge portion of the die.

On FIGS. 3, 4, and 8, it will be noted that power member 30 has a counterbore 32 formed therein complementary respective to members 20 and 24 so that the mandrel is always arranged in indexed relationship therewith. Elongated slot 34 is formed longitudinally respective of the table so that the mandrel can be moved within the slot and longitudinally respective of the table.

Spaced arms in the form of adjustment plates 36 and 37 are spaced from one another and pivotally secured to the table by means of pivot pins 38 and 39 thereby enabling the positioning pins 40 and 41 to be moved toward and away from one another when handle 42 rotates threaded member 43. Member 43 threadedly engages member 41 while the free marginal end 42 is journaled to the pin 40. The rotatable fixed dies and therefore positioned at the pivoted or swingable end of the arms. Handle 46 cooperates with the illustrated arcuate slotted member 50 to provide a friction lock for member 36. Member 37 requires no friction lock for reasons which will be better appreciated later on in the disclosure.

The before mentioned power member 30 has opposed end portions 52 and 54. The member is slidably captured within L-shaped web members 56 and 58 so that the power member can slide in low friction relationship longitudinally of the table an amount which enables full travel of the mandrel along the length of slot 34.

As seen in FIGS. 3 and 4, a centrally located downwardly depending member 60, also called an "ear," is rigidly affixed to the marginal forward end portion of member 30 and has rigidly affixed thereto a pin 62 which has opposed ends arranged normally thereto. Cylinder 64 of a hydraulic unit has a piston 66 thereof journaled to the before mentioned pin, with the cylinder being journaled to pin 68. Biasing means in the form of opposed springs 70 and 71 are arranged on opposed sides of the hydraulic unit and have the depending ends thereof affixed to the pins 62 and 68, thereby forming a return biasing means for the mandrel. Hence, the hydraulic unit reciprocates the power member forward while the biasing means reciprocates the power member in the opposite direction.

Spaced vertical webs 72 form a mounting means for pin 68 and is rigidly affixed to the table and to the illustrated member 74. Member 75 is attached to the table and provides additional support for the apparatus.

Flow connection 76 is fluid connected to flow control valve 78 which in turn is connected to hydraulic pump 80 and to the reservoir 82. Valve controller 79 can be engaged by the foot to control the flow of hydraulic fluid to and from the cylinder 64. Electric motor 81 is electrically connected to the motor controller 84 while switch 86 enables the entire apparatus to be de-energized.

In operation, a suitable source of current is connected to the controller and the switch 86 turned on, thereby causing induction motor 81 to actuate the pump 80, thereby providing a source of hydraulic pressure for the cylinder 64. When lever 79 is pushed in a downward direction by the foot, valve 78 causes fluid to flow into the cylinder 64 thereby moving piston 66 which in turn moves pin 62, vertical webs 60, power member 30, and the mandrel 20 longitudinally within its slot.

Prior to moving the mandrel in a forward direction, the proper size movable die is selected to provide a U-bolt having the proper desired radius of curvature. The fixed roller dies are properly positioned relative to one another so that the distance between the spaced bolt engaging surfaces of the roller dies is exactly equal to the measured distance between legs L1 and L2 of the finished U-bolt. A threaded bar 19 is placed between the leading face 28 of the die and abuttingly engages each of the rollers 16 and 17. The piston is reciprocated within the cylinder by engaging valve control rod 79 with the foot, thereby causing rollers 14, 16, 17 to move relative to one another as illustrated in FIG. 2a, 2b, and 2c.

Applicant has discovered that by removing the area between 28 and 27' of the die 14, the bolt 19 will not creep forward into the illustrated position 29 while it is being bent into a U-shape in accordance with FIGS. 2a, 2b, and 2c. The presence of the flat face or leading edge 28 causes the stock 19 to be bent into a perfect radius of curvature 119 as axis C1 moves through axis C2. The curvature 19' or 119 is controlled by the amount of material removed between 27' and 28. Ordinarily, 15 percent to 40 percent of the area of the die, viewed in plan, is is removed in order to attain the desired configuration at 119.

The reason that the removal of the material at 28' results in a radius of curvature 119 which coinsides with radius 27' of FIG. 7, for example, is because the bolt is engaged by the outer periphery 27 of the die as the bending operation commences, and since the bolt is originally deformed into an initial bend as a result of being forced between the three dies, the marginal area of the bolt is caused to assume an undesirable sharp bend seen illustrated at 29 in FIG. 2b. By engaging a larger surface area of the bolt by a larger bearing area 28, a more uniform and desirable radius of curvature 119 is achieved rather than an undesirable sharp bend 29.

Release of lever 79 causes the fluid flowing through pump 80 to bypass the cylinder the flow to the reservoir 82, whereupon biasing means 70 urges pins 62 and 68 toward one another, thereby returning the mandrel to its initial position respective to the slotted table. The apparatus is now in stand-by configuration awaiting fabrication of the next U-bolt.

When it is deemed desirable to fabricate U-bolts of different configurations, various different diameter dies can be substituted for the one illustrated at numeral 14. For example, should a square U-bolt be deemed desirable, the apparatus disclosed in FIGS. 10 and 11 can be employed in order to fabricate each 90.degree. bend of a square U-bolt. The amount of bend imparted into a piece of stock can be regulated by the distance traveled by the moving die respective to the spaced fixed dies.

Claims

I claim:

1. In a bending machine for bending metal stock to produce U-bolts and the like, a longitudinally extending table having a longitudinally extending slot formed therein;

an elongated slidable power member underlying said slot, means slidably capturing said power member to said table in a slidable and abutting manner to slidably engage abuting surfaces of said power member and said table;

a mandrel attached to said power member and having a free marginal end portion extending through said slot; a movable die affixed to the marginal free end portion of said mandrel;

spaced fixed dies equally spaced apart and from said movable die;

spaced arms pivotally secured to said table and having a swingable end to which there is attached said fixed die;

means for reciprocating said power member to move said mandrel along said slot to cause said movable die to move between said fixed dies;

so that the central marginal length of a piece of metal stock placed against said fixed dies can be engaged by said movable die and bent into a curved configuration.

2. The machine of claim 1 wherein said pivoted end of said spaced arms are adjustably secured to one another by a tie rod;

means for adjusting the effective length of said tie rod, thereby enabling selection of the distance between said fixed dies.

3. The machine of claim 2 wherein said fixed dies include means rotatably securing them in fixed relationship to said arm.

4. The machine of claim 1 wherein said power member is a rectangular member, and said means slidably capturing said power member is opposed downwardly depending web members which form said table into a monocoque configuration, the lowermost marginal longitudinally extending edge portion of said web members being inwardly turned for bottom supporting said power member therefrom.

5. The machine of claim 1 wherein said means for reciprocating said power member is a hydraulic cylinder, and biasing means are attached between said power member and said table for returning said power member to a position of rest;

a fixed ear downwardly attached to said table, a pin received through said ear and the cylinder of said hydraulic unit, a movable ear downwardly attached to said power member, a pin received through said ear and the piston of said hydraulic unit,

said biasing means affixed to said pins and biasing them toward one another.

6. In a machine for bending a bendable member such as rods, bars, tubes, u-bolts, and the like, the combination comprising a stationary plate member having a longitudinally disposed slot formed therein, a mandrel received through said slot and movable longitudinally along the length thereof, a bending die affixed to said mandrel and movable therewith;

a power member underlying said plate member, means moving said power member along the length of said slot, said mandrel being affixed to said power member and movable therewith;

a pair of spaced arms located on either side of the slot, each said arm is pivotally secured to said plate member, means forming a fixed die at one end of each arm, means by which said fixed dies may be moved toward one another, said fixed dies being arranged respective to said bending die so that the latter is moved through the former by the action of said power member;

so that the bendable member can be placed with the fixed and bending dies arranged on opposite sides thereof, the power member moved along the slot, thereby causing the dies to engage and deform the bendable member into a bent configuration.

7. The combination of claim 6, wherein said mandrel is removably affixed to said power member; and, said bending die is removably affixed to said mandrel; said bending die having a flat leading edge portion bounded on either side thereof by a curved trailing surface, with the curved trailing surface having a radius of curvature substantially equal to the radius of curvature desired of the bent member.

8. The combination of claim 6 wherein said bending die is a cylindrical member except for the leading edge portion thereof which is made into a flat surface for initially contacting the bendable member.

9. The combination of claim 6 wherein said bending die has a cylindrical geometrical configuration with the leading edge portion thereof being flat so that the flat leading edge portion first contacts the bendable member and thereafter the spaced curved portion of the cylinder contacts the bendable member.

10. The combination of claim 6 wherein said power member is an elongated square piece of metal stock, means slidably capturing said power member in underlying abutting relationship respective to the lower surface of said plate member;

said means for moving said power member being a hydraulic cylinder interposed between the plate member and the power member;

and further including means for controlling the action of said hydraulic cylinder so that the poiston thereof reciprocates in either of its two directions of movement.