US3869926A

US3869926A - Device for bending serpentine struts

Info

Publication number: US3869926A
Application number: US398414A
Authority: US
Inventors: Klaus Keller
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-21
Filing date: 1973-09-18
Publication date: 1975-03-11
Anticipated expiration: 1992-03-11
Also published as: ES417966A1; DE2246392C3; NL7311771A; FR2200066B1; DE2246392A1; SE409422B; CA993334A; FR2200066A1; AT324077B; JPS4993259A; DE2246392B2; IT991840B

Abstract

A device for bending strips of metal to form serpentine struts by passing the strips of metal through two sets of bending tools moving simultaneously in a direction parallel to the direction of travel of the strip of metal. The bending tools are spaced. Further, each of the bending tools are carried on a chain and the number of bending tools on each of the chains is only a fraction of the number of chain members of each of the associated chains.

Description

:1 ntte States atent 1191 1111 3,869,926 Keller Mar. 11, 1975 DEVICE FOR BENDING SERPENTINE 2,777,478 1/1957 Stohlquist 72/190 STRUTS 7 3,064,694 11/1962 Brook et a1. 1 1 72/190 3,382,695 5/1968 Ca e 72/190 [76] Inventor: Klaus Keller, Blumenstrasse 17, p

8192 Gergtsrled Germany Primary Examiner-Wesley S. Ratliff, Jr. [22] Filed: Se t. 18, 1973 Attorney, Agent, or Firm-Woodhams, Blanchard and p F1 21 Appl. No.: 398,414

57 ABSTRACT [30] Foreign Application Priority Data 1 Se t 21 1972 Ger an 2246392 A devlce for bending strlps of metal to form serpenp m y tine struts by passing the strips of metal through two sets of bending tools moving simultaneously in a direc- [52] [1.8. CI. 74/25, 72/190 tier-1 parallel to the direction of travel of the strip of [51] lnt.Cl. F16h 21/16 1 Th b l f [58] Field of Search 72/190- 74/25 meta" endmg ?respaced- E each the bending tools are earned on a chain and the num' ber of bending tools on each of the chains is only a [56] References cued fraction of the number of chain members of each of UNITED STATES PATENTS the associated chains, 2,097,193 10/1937 Jacobs 72/190 2,649,888 11/1953 Fay 72/190 10 Clams, 5 Drawlng Figures FATENTEDHARI 119. 5 R. 869 926 sum 1 or g 1 DEVICE FOR BENDING SERPENTINE STRUTS This invention relates to a device for bending serpentine struts, in particular for lattice beams, from a strand material which passes through two sets of bending tools, movably journaled on chains by control elements, transversely to the travel of the material in the bending region, said chains being moved in opposing paths in said bending region.

In known devices of this type, a bending tool is journaled on each chain member of the employed articulated chains. The division of the bending tools thus concurs with the division of the chain. The joint plates are constructed as special parts for this purpose and may serve to journal and guide the bending tools. Hence, they must have a considerable size, thereby causing the chain division to be correspondingly large. This in turn means that sprocket wheels of large diameter are required to drive the chains. This is primarily due to the fact that at least 19 teeth are required on one sprocket wheel to ensure smooth running of the chainso that the sprocket wheel will take up a correspondingly large amount of room in the case of a large chain division. This in turn means that the entire device will be large, heavy, bulky and expensive to manufacture. In addition, much driving power is required to move the voluminous structural parts.

The present invention is based on the object of providing a device of the class described hereinbefore which is small in construction and which requires little driving energy.

This object is accomplished in accordance with the invention in that the number of bending tools of each set amounts to only a fraction of the number of chain members of the associated chain.

Whereas the chain and the bending tools are functionally integral with their journaling and guiding parts in the known devices, the invention departs in principle from this conception. It solves the functional unit by reorganizing it into a chain having a small division and small members and a set ofbending tools having a substantially larger division.

Small sprocket wheels could consequently be pro vided as a result of employing a chain with small members, thereby reducing the size and mass of the entire device which, in turn, not only takes up less space, but also reduces the necessary driving power. Considerably fewer bending tools are also required on the whole, since their number can be limited to the amount functionally necessary while the number of bending tools in the known devices was determined by the number of chain members which could not be reduced or else jerky operation had to be put up with. A special advantage can be seen in the fact that commercial, even standardized structural parts can be employed for the chains and sprocket wheels and are considerably less expensive to purchase than special chains.

The number of bending tools expediently amounts to a fourth to a sixth, preferably a fifth, of the number of the chain members. Approximately to 25, preferably l8, bending tools may be provided per chain. This construction produces a device which is small in construction, but which nevertheless is very powerful and efficient.

Advantageously, the bending tools are journaled on lateral extensions of the chain pins of flat-link articulated chains so as to be eccentrically pivotal. This 2 makes it possible to employ commercial articulated chains with laterally extended chain pins so that no journaling or guiding members have to be provided on the joint plates. By correspondingly disposing the eccentrical pivot bearings relative to the bending tools, it is also possible to achieve flex-free bending of the material, i.e., bending is executed in one direction of bending only.

The bending tools of each set are preferably disposed between parallel chain pairs and are journaled on both sides. This produces a stable mounting which can transmit large forces without requiring the bearing parts to have especially large dimensions.

Other advantageous features can be seen from the following description of one embodiment of the invention, in which:

FIG. 1 is a schematic side elevation ofa device in accordance with the invention;

FIG. 2 is a front elevation of the device according to FIG. 1;

FIG. 3 is a top elevation with a partial horizontal section of the device according to FIGS. 1 and 2, and

, FIG. 4a is a side elevation; and

FIG. 4b is a top elevation of a bending tool.

In the drawing, 1 is a column mount forming the frame of the device according to the invention and comprising four verticalcolumns la-ld. A first bearing unit 2 is rigidly mounted at the bottom of the column mount. At the top of the vertical columns la-ld, a frame 3 is mounted so as to be adjustable in height by means of a spindle drive 4 and is journaled so as to be clamped in a stationary position by means of clamping levers 5. The frame supports a second bearing unit 6. Two

shafts

7a and 7b or 8a and 8b are journaled in longitudinal spaced relation in each of the

bearings units

2 and 6. The shafts 7b, 8b can be driven synchronously by a common motor 11 via

universal joint shafts

9 and 10 and a branch gearbox 12. Two double sprocket wheels 13a, b, 14a,b, l5a,b and l6a,b are keyed (as in FIG. 3) onto each of the shafts mentioned above in axial spaced relation. Double chains 17, l8, l9 and 20 respectively pass about the associated pairs of

double sprocket wheels

13a, 14a or 13b, 14b or 15a, 16a or 15b, 16b. These double chains are designed as commercial, standardized roller chains with tab members 21 and joint pins 22 as can be seen from FIG. 3. The bearings of the shafts 7b and 8b can be displaced by means of clamping devices 23 in order to tighten the chains. The roller chains may be supported against sagging in the region between the sprocket wheels, the supports (not shown) abutting on the chain rollers.

Bending tool units generally designated with reference numeral 24 are journaled between adjacent

double chains

17 and 18 or 19 and 20. The bending tool units 24 are illustrated in more detail in FIGS. 4a and 4b. Each unit has a mounting member 25 in which a bar-shaped bending tool 26 with a rounded head 26a is interchangeably journaled by means of a thumbscrew 27. Guide rollers 28 are laterally journaled on the mounting member and their purpose shall be explained hereinbelow. Each mounting member is also provided with a bearing yoke 29. Extended sections 22a of chain bolts, or joint pins, 22 engage the bearing yoke 29. For example, the extended sections 22a may be formed such that chain bolts from triple chains are used at the respective locations.

The arrangement is created such that the chains 17 to 20 are made up of relatively small chain members, for example, 90 chain members. The bending tool units 24, however, are only journaled on every fifth chain joint pin 22 so that the bending tools are arranged or are spaced at a substantially greater distance than the chain members. f

A cam disc 30 is rotatably journaled on the shaft 7a in the plane in which the bending tool units 24 move, but is prevented from rotating by means of a stationary guide rail 31 having a run-out section 31a. As can be seen from FIG. 3, each cam disc 30 and each guide rail 31 consists of two identical parts which are laterally located in spaced relation. The spacing is selected such that the guide rollers 28 can respectively roll on one of the two parts. A corresponding arrangement of cam discs and guide rails is provided for the bending tool units 24 of the upper pairs of

double chains

19 and 20. Only one guide rail 32-corresponding to guide rail 31 is seen in FIG. 1. A two-part cam disc 33 corresponding to the cam disc 30 can also be recognized in FIG. 2.

The inventive device operates as follows:

A strand material 34, for example round or flat iron bars, is removed from a storage device'(not shown) and is introduced into the inventive device in the direction of the arrow P in FIG. 1 via a set of rollers 35 which serves to straighten and, if desired, cold-stretch the strand material. In so doing, the material 34 arrives at the plane in which the bending tools 26 are moving. In the infeed area, or bending zone, each of the bending tools, which is journaled on the associated pair of

chains

17, 18 or 19, 20 and which moves therewith in the direction of the arrow shown in FIG. 1, is pivoted out of the position designated 26' in FIG. 1 and into the position designated 26' by the rolling action ofthe guide rollers 28 on the

cam discs

30 and 33. In position 26, the bending tool just begins to engage the strand material 34. In position 26-, it has already bent one section of the strand material 34 to form a complete strut so that the strand material leaves the device as a serpentine strut 36. Theplane occupied by the material in the device may be termed the bending plane. The path of the bending tools from position 26 to position 26", in which the bending process has already been terminated, corresponds to half the division of the serpentine strut 36. This causes the struts of the serpentine strut 36 to be bent without any temporal overlap. Only one bending tool 26 is engaged in bending at one time.

The bending tools 26 are journaled and are con-. ducted during their bending process such that the strand material is always bent in one bending direction only. For this purpose, the pivot bearings ofa mounting member are disposed (1) along the main perpendicular of the straight line connecting the center points of curvature of the bending tool head 26a, in its initial and final bending position, (2) outside the serpentine strut 36 to be formed, as well as (3) adjacent the advancing turning point.

This guarantees that the strand material is deformed in a flex-free manner, i.e., in a way which prevents the strut from being bent back and forth during its formatron.

After leaving the cam discs or 33, the guide rails 31 or 32 maintain the bending tools 26 for a distance in engagement with the formed serpentine strut 36 and the bending tools 26 leave the strut 36 in the region of 4 the discharge section 31a without further deforming the resultant struts.

' In order to vary the height of the serpentine strut to be formed, second bearing unit 6 is adjusted in height by means of the spindle drive 4. In so doing, it is necessary in the illustrated embodiment to exchange the 'tools 26. The bending tool units 24, however, can be designed such that is is possible to vary the height of the serpentine struts without exchanging the tools.

The invention is not restricted to the embodiment shown. In particular, the number of chain members and of bending tools can be varied. The sole decisive factor is that a fine division of the chain can be used vis-a-vis a substantially coarser division of the arrangement of the bending tools. Furthermore, single or triple chains can be employed in place of double chains. It is also possible in principle to journal the bending tools in an overhung manner on chain bolts projecting unilaterally. In order to pivot the bending tools into the final bending position, several tripping devices, for example rotating cam discs or guide assemblies, can also be employed. A- shiftable or shiftrotatable mounting, for exainple in guide bar slots, could also be considered in place of a pivotal mounting of thebending tools.

Although a particular preferred embodiment of the invention has been disclosed above for illustrative purposes, itw ill be understood that variations or modifications thereof which lie within the scope of the appended claims are fully contemplated.

The embodiments of the invention in which an exclusive property or prvilege is claimed are defined as follows:

l. A device for bending serpentine. struts, usable in lattice beams, from strand material, comprising:

two sets of bending tools between which the strand material passes for bending, said strand material defining a bending plane in which it travels in one direction through a bending zone;

two chain pairs, each chain pair having two rotatable link chains each comprising a number oflink members, the number of bending tools of a said set being only a fraction of thenumberof link members in a said chain, the chains of each chain pair being located in parallel side-by-side relation, each chain pair transversely and movably supporting the bending tools ofa corresponding set for movement through said bending zone, said chains of each chain pair being rotatable in planes parallel to said bending plane, the chains of each pair being spaced on opposite sides of said bending plane and having opposed side surfaces which face each other, said bending tools of each set being supported between said spaced side surfaces of the corresponding pair of chains, said chains of each pair including inwardly extended opposed joint pins each having an end carried by the corresponding chain, a said bending tool being eccentrically pivoted on said extended joint pins.

2. A device according to claim 1 in which each said chain comprises a double chain.

3. A device according to claim 1 including a column mount fixedly mounting a pair of vertical columns on each side of said bending plane, a frame unit spaced from said column mount and journaled on said columns and means for adjusting the height of said frame unit with respect to said columns, opposed bearing units fixed on saidcolumn mount and frame unit, two pairs of parallel shafts rotatably supported adjacent their ends by respective ones of said bearing units and corresponding to said two chain pairs, the shafts of each pair being spaced along the path of travel of said strand material, and extending transversely through said bending plane, said shaft pairs lying respectively above and below the path of saidstrand material, sprockets on said shafts for carrying said chains in closed loop orbits, whereby the serpentine strut height corresponds to the adjusted spacing of the column mount and frame unit.

4. A device according'to claim 3 in which each shaft carries sprockets spaced on opposite sides of said bending plane, said shafts having bearings carried by said bearing units outboard of said sprockets.

5. A device according to claim 3 including motor means adjacent said shafts and universal joint shafts coupling said motor means to at least one shaft of each chain pair for rotatably driving said chain pairs in synchronism through their sprockets.

6. A device according to claim 3 includingcam discs journaled on ones of said shafts for rotation of said one shafts with respect thereto, said one shafts being those closest to the strand material input to the device, said cam discs being spaced on opposite sides of said bending plane and inboard of said sprockets and being engageable with eccentric portions of said eccentrically pivoted bending tools for controlling pivotal motion of successively contacted bending tools in said bending zone and with respect to the joint pins carrying said bending tools, and further including guide rails fixed with respect to the axes of said shafts and extending from corresponding cam discs parallel to the bending plane and toward the outlet end of the device for determining the pivoted orientation of corresponding bending tools leaving the cam discs.

7. A device according to claim 1 in which each bend-- ing tool comprises a substantially L-shaped unit straddling the bending plane, one leg of such L-shaped unit terminating in a rounded bending toolhead engageable with said strand material for bending same, the other leg of said .L-shaped unit ending in yoke means transversely receiving said extended joint pins from the chains on opposite sides thereof for eccentrically pivotally locating said bending toolhead with respect to said extended joint pins.

8. A device according to claim 7 including rotatable shafts extending transversely through said bending plane and carrying axially spaced sprockets for supporting said pairs of chains, cam and guide means adjacent and between said sprockets and bending plane, said L-shaped bending tool units each including coaxial rollers on said other leg thereof and on opposite sides of said bending plane for engaging corresponding ones of said cam and guide means and thereby controlling eccentric pivoting said bending tool with respect to its supporting chain pair, said other leg with its rollers trailing said yoke means as said chains move adjacent and with said strand material, and said one leg trailing said rollers and extending away from said chains to contact said head with said strand material.

9. A device according to claim 1 wherein the bending tools of each set each have both sides thereofjournaled on said chains of the corresponding pair.

10.- A device according to claim 1 wherein the number of bending tools is a fourth to a sixth of the number of chain members and approximately 15 to 25 bending tools are provided per chain.

Claims

1. A device for bending serpentine struts, usable in lattice beams, from strand material, comprising: two sets of bending tools between which the strand material passes for bending, said strand material defining a bending plane in which it travels in one direction through a bending zone; two chain pairs, each chain pair having two rotatable link chains each comprising a number of link members, the number of bending tools of a said set being only a fraction of the number of link members in a said chain, the chains of each chain pair being located in parallel side-by-side relation, each chain pair transversely and movably supporting the bending tools of a corresponding set for movement through said bending zone, said chains of each chain pair being rotatable in planes parallel to said bending plane, the chains of each pair being spaced on opposite sides of said bending plane and having opposed side surfaces which face each other, said bending tools of each set being supported between said spaced side surfaces of the corresponding pair of chains, said chains of each pair including inwardly extended opposed joint pins each having an end carried by the corresponding chain, a said bending tool being eccentrically pivoted on said extended joint pins.

3. A device according to claim 1 including a column mount fixedly mounting a pair of vertical columns on each side of said bending plane, a frame unit spaced from said column mount and journaled on said columns and means for adjusting the height of said frame unit with respect to said columns, opposed bearing units fixed on said column mount and frame unit, two pairs of parallel shafts rotatably supported adjacent their ends by respective ones of said bearing units and corresponding to said two chain pairs, the shafts of each pair being spaced along the path of travel of said strand material, and extending transversely through said bending plane, said shaft pairs lying respectively above and below the path of said strand material, sprockets on said shafts for carrying said chains in closed loop orbits, whereby the serpentine strut height corresponds to the adjusted spacing of the column mount and frame unit.

4. A device according to claim 3 in which each shaft carries sprockets spaced on opposite sides of said bending plane, said shafts having bearings carried by said bearing units outboard of said sprockets.

6. A device according to claim 3 including cam discs journaled on ones of said shafts for rotation of said one shafts with respect thereto, said one shafts being those closest to the strand material input to the device, said cam discs being spaced on opposite sides of said bending plane and inboard of said sprockets and being engageable with eccentric portions of said eccentrically pivoted bending tools for controlling pivotal motion of successively contacted bending tools in said bending zone and with respect to the joint pins carrying said bending tools, and further including guide rails fixed with respect to the axes of said shafts and extending from corresponding cam discs parallel to the bending plane and toward the outlet end of the device for determining the pivoted orientation of corresponding bending tools leaving the cam discs.

7. A device according to claim 1 in which each bending tool comprises a substantially L-shaped unit straddling the bending plane, one leg of such L-shaped unit terminating in a rounded bending toolhead engageable with said strand material for bending same, the other leg of said L-shaped unit ending in yoke means transversely receiving said extended joint pins from the chains on opposite sides thereof for eccentrically pivotally locating said bending toolhead with respect to said extended joint pins.

9. A device according to claim 1 wherein the bending tools of each set each have both sides thereof journaled on said chains of the corresponding pair.