Untitled record

Application filed April 1, 1889. Serial No. 305,622, (No model,)

To all whom it may concern:

Be it known that we, Albert Hirshheimer and Charles M. Mueller, citizens of the United States, residing at La Crosse, in the 5 county of La Crosse and State of Wisconsin, have invented certain new and useful Improvements in Machines for Bending Wood; and we do declare the following to be a full, clear, and exact description of the invenlo tion, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form 15 a part of this specification.

Lilis invention relates to improvements in mechanism for bending wood; and the object is, primarily, to apply the power in such a manner and at such points that the fibers of the 20 wood shall, be compressed longitudinally at the same, time and to the same extent that pressure is exerted in a lateral direction; in the construction and means for controlling the. bed, and in the means for lifting the bent 25 article and former from the brackets when the operation is completed, and, further, in the. relative, positions of the centers upon which the tilting brackets turn and the upright shoulders upon the same, by means of 30 which the pressure is exerted upon the ends of the blank.

The. invention is an improvement upon the machine described in Letters Patent No. 391,794, granted to us October 30, 1888, (ma35 chine for bending staves,) and in the principal features of construction and arrangement are similar thereto.

Our improvements are illustrated in the accompanying drawings, in which—

Figure 1 is a front view of the machine. Fig.. 2 is a fragmentary side view, partly in vertical section, showing the yielding bed and the means for controlling the same. Figs. 3 . and 4 are detail views of the blank-bending 45 tilting brackets. Figs. 4“ and 5 are details showing the relative positions of the centers and .abutments of the tilting brackets.

. 1 is the upright main frame, in which reciprocates vertically the presser-block 2, ac50 tuated by pitman connection with suitable driving-gear at the top of the frame. At a suitable height upon the frame is a horizontal table 3, to which are secured at suitable distances from the path of the presser-block the blank-supporting brackets 4 4. These 55 brackets are so located that the presser-block shall be over the middle of the blank when resting upon the brackets. The brackets are substantially of the form described in our patent previously mentioned, witli the excep- 60 tion that a certain fixed relation between the position of the centers a upon which the tilting sections 5 5 turn, and the upright shoulders & & upon the same, against which the blank abuts, is found to be of considerable 65 importance in. order that the bending may be accomplished perfectly without danger of slivering or otherwise parting the fibers of the wood. The centers should be so located with reference to the abutment, and the 70 brackets should be so located upon the table, that the distance between the axis and the point c from which the shoulders rise and the distance apart of the two opposite abutments when the beds upon which the blank 75 rests are horizontal, and when, consequently, the said abutments are vertical, have such relation to each other that the former is equal to one-half the difference in length of the semi-circumference and the diameter of a 80 circle having a semi - circumference equal in length to said last-named distance—that is, the distance between the two abutments, by which the end pressure is exerted when in normal position, being represented by a 85 straight line, the distance between the axis upon which the bracket turns and the apex c of the angle formed by the abutment and the supporting-surface is equal to one-half the difference between the length of said 90 line and the diameter of a circle whose semi-circumference has the same length as said line. By this arrangement the abutments always lie in the line of the radius of curvature at that particular point, and there 95 is no possibility of the end of the blank becoming slivered by unequal pressure at different points, and the breaking and slivering bf the blank at the center by reason of unequal pressure in different parts of the blank 100

426,641 are also prevented. The presstire at the ends and in the center is always equal, exerted at the same time, and equally distributed throughout the tvhole length of the blank.

‘ 5 In the middle of the table immediately underneath the follower-die is mounted the yielding bed 6, having either a flat or concave upper surface, according to the style of work to be done, and located upon the top of an io upright bar mounted in suitable bearings firmly secured in the frame-work, so as to slide up and down therein. Around this bar, or otherwise connected with said bed in position to raise the same in its bearings, is a 15 stiff spring 7, which acts normally to keep the said bed on a level with the supporting-surfaces of the brackets, so that when the blank is introduced under the die it shall rest evenly upon the three supports. The three partial 20 supports are connected and the bed made continuous by means of arms 8 8, extending inwardly from the front of each tilting bracket, as shown in Fig. 1, and entering recesses in the under side, of the center becl 6 to assist in 25 making the operation of the bed and brackets simultaneous when the blank is operated upon by the follower-die. As a modification of this construction,we have shown a strap of steel connecting the bed-surface of the two 30 opposite tilting brackets and secured to them and to the bed. This construction is in some respects preferable, as a continuous yielding back is afforded for the blank, and in connection with the evenly-distributed pressure 35 obtained by this construction slivering is impossible.

For the purpose of bending staves we make use of the former described in our previous patent before mentioned. It is found, how40 ever, that the pressure upon the ends of the blanks exerted by the tilting brackets is so great as at times to make it difficult to lift the former and blank off the brackets when the operation is completed. To obviate this 45 difficulty we have attached to the front and back of the follower grappling-hooks 9 9, which, as the follower lowers, engage underneath the edges of the center bed in notches 10 10. and which lift the same and the 50 former carrying the stave therewith, releasing it'from thebrackets. To render the operation of these grappling-hooks entirely automatic they are hinged at the front and back, respectively, of the follower, as shown, and 55 suitable cams or their equivalent 11 11 are located upon the frame in position to release the same from engagement with the bed when it has risen high enough to free the former from the brackets and to allow the same to 60 drop back into position to engage with the bed upon the downward movement of the follower. The most important function of the hooks, however, is to grip the bed 6 at the moment when pressure is begun to be ex65 erted upon the blank by the downward move. ment of the die, thus grasping the blank closely between the bed and the former and preventing the bed from moving away from the blank as the pressure is increased. The bed is held closely up against the blank, even 70 though the spring may not be sufficiently strong to hold the same in-place of itself. The upper surface of the center bed 6 beingconcave in form when used for this class of work to correspond with the outside of a fin- 75 ished stave, the blank is thus firmly supported at all points.