US3129745A - Safety device for power leaf brake - Google Patents

Description

April 21, 1964 H. HADDEN AEETY DEVICE FOR POWER LEAF BRAKE Filed Aug. 10. 1961 INVENT OR.

I'ENRY HADDEN ATIORNEYS United States Patent 3,129,745 SAFETY DEVICE FOR PQWER LEAF BRAKE Henry Hadden, Bedford, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio Filed Aug. 10, 1961, Ser. No. 130,557 1 Claim. (Cl. 15339) This invention relates to a power leaf brake and, more particularly, to a safety device for a power leaf brake.

Power leaf brakes are a type of press brake commonly used in industry for the cold bending of metal sheets, bars, plates and the like. The type of power leaf brake here concerned comprises a table to which work may be clamped having a normally raised workpiece engaging member with a normally vertical leaf member depending rearwardly therefrom. When the brake is operated, the table rotates forwardly to effect a bend and then returns to its original position. During this operation the rearward leaf is, of course, also rotated. Since the operator is usually standing close to the machine to position the material before clamping it in place for bending, there is a constant danger that the rearward leaf will pinch the operators foot in its return to normal position.

It is therefore an object of this invention to provide a safety device for a power leaf brake. Another object is to provide such a device that will function as a safety foot guard for such a brake.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claim, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a perspective view of a power leaf brake in its normal or rest position;

FIG. 2 is a partial sectional view showing the safety guard and its mounting taken along line 2-2 of FIG. 1;

FIGS. 3 and 4 are partial sectional views similar to FIG. 2 showing the leaf member and guard in progressively raised positions.

Referring now to the drawings in detail, the power leaf brake is shown having a rotatable table which comprises a normally raised workpiece engaging member or ram 11 and a normally vertical leaf member 12. The workpiece engaging member 11 has a projecting forming or bending die 13 which when the table is rotated presses the workpiece in a die-pit (not shown). The leaf member 12 depends from the rear of member 11 and when the table is rotated the leaf member 12 swings out from a nearly vertical position to a more horizontal position as shown in FIGS. 2, 3 and 4. The power leaf brake shown is mounted over a well or pit 14 in the floor to receive the lower part of the leaf member 12. It is obvious that during operation it would be relatively easy for an operator to have his foot caught in the space 15 shown in FIG. 4 when the leaf member 12 descends again into the well 14. This is effectively prevented by the safety foot guard 16. The guard 16 is shown as a grill having a series of horizontal bars 17 with supporting cross pieces 18 thereon. The guard has a pair of short inwardly directed pins 19 which fit loosely within a pair of horizontal sockets 20 which are welded or otherwise fastened to the leaf member 12. The bottom horizontal bar on the guard 16 has a roller 21 thereon which may be of any suitable tubular material, including wood or plastic. The floor surrounding the leaf member 12 and well 14 is preferably covered with a rough surfaced steel mat 22 to protect the floor and also to give the operator better foot traction.

When the leaf member 12 is at rest as shown in FIGS. 1 and 2, the guard 16 effectively covers the space between the well 14 and the leaf member 12 so as to prevent the operator from stepping therein; the same is true when the leaf member 12 is only slightly raised as shown in FIG. 3. When the leaf member 12 is raised even higher as shown in FIG. 4, it is obvious that the operator may put his foot underneath the guard roller 21 but is prevented from getting his foot underneath the leaf member 12. Since the guard 16 is hinged when it descends, his foot will not be hurt.

The roller 21 serves the purpose of permitting the bot tom of the guard to ride smoothly over the mat 22. In addition, the action of the roller 21 on the guard permits the operator to more quickly and easily withdraw his foot therefrom since the freely rolling surface prevents any projections on the shoe from being caught by the guard.

The brake itself is a conventional one having electric push button controls 23 and being powered by hydraulic plungers 24. Since, however, details of construction of the brake, other than those described, form no part of this invention it will not be further discussed herein.

This invention has the advantage of rendering a potentially dangerous item of machinery safer with a minimum of structural modifications and without detracting from the smooth operation and efficiency of the machine.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claim or the equivalent of such be employed.

I therefore, particularly point out and distinctly claim as my invention:

In a power leaf brake disposed partially in a floor well and having a leaf member which moves to and from a substantially vertical condition at one side of the brake in normal use of the same, with the bottom of said leaf member swinging out of and into the well below the floor, a safety foot guard pivotally attached to said leaf member at areas spaced from the bottom of said leaf member for movement therewith and relative thereto, said guard comprising a horizontally elongated grill provided at its bottom with a horizontal bar member having a cylindrical roller mounted thereon, said roller providing smooth rolling movement of said guard on said floor adjacent said well, said foot guard extending partially beyond the bottom of the leaf member when the latter is elevated above the floor to provide an effective extension thereof with the guard engaging the floor adjacent the well at such side of the brake as the leaf member swings from its raised to its lowered condition, the pivotal attachment of the guard providing for partial arrest of the same as a result of such engagement with the floor and consequent movement relative to the leaf member whereby said guard bridges the opening between said floor well and said leaf member in the lowered condition of the latter, said guard thereby preventing the insertion of objects through said opening during said lowering movement of said leaf member and the guard member to the lowered condition of the latter.

References Cited in the file of this patent UNITED STATES PATENTS 1,998,245 Laukhuff Apr. 16, 1935 3,018,495 Hosbein Jan. 30, 1962 FOREIGN PATENTS 229,870 Great Britain Mar. 5, 1925 781,722 Great Britain Aug. 21, 1957

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