CA1234039A - Adjustable bolster block - Google Patents
Adjustable bolster blockInfo
- Publication number
- CA1234039A CA1234039A CA000485726A CA485726A CA1234039A CA 1234039 A CA1234039 A CA 1234039A CA 000485726 A CA000485726 A CA 000485726A CA 485726 A CA485726 A CA 485726A CA 1234039 A CA1234039 A CA 1234039A
- Authority
- CA
- Canada
- Prior art keywords
- wedge
- die holder
- central plane
- plane
- wedge support
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
- B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means
- B21D5/0272—Deflection compensating means
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Bending Of Plates, Rods, And Pipes (AREA)
Abstract
ABSTRACT
An adjustable bolster block to be disposed between the ram or bed of a brake press and a die is disclosed which permits crowning to compensate for deflection of the brake press under loading. The bolster block includes a double wedge support coupled to the ram or bed and a die holder to hold the die, Two wedges are sandwiched intermediate the wedge support and die holder, one on each side of a central plane passing longitudinally through the bolster block. The wedges have cam surfaces which engage complementary cam surfaces on each of the wedge support and die holder. Movement of the wedges toward or away from each other varies the spacing between the wedge support and die holder. The wedges can be bent in directions towards and away from each other symmetrically about a central plane to vary their separation along their length and to thereby vary the spacing of the die holder from the wedge support along their lengths so as to crown the die holder, The symmetric configuration minimizes net bending moments acting on the die holder tending to bend or twist the die holder in directions normal to the central plane.
An adjustable bolster block to be disposed between the ram or bed of a brake press and a die is disclosed which permits crowning to compensate for deflection of the brake press under loading. The bolster block includes a double wedge support coupled to the ram or bed and a die holder to hold the die, Two wedges are sandwiched intermediate the wedge support and die holder, one on each side of a central plane passing longitudinally through the bolster block. The wedges have cam surfaces which engage complementary cam surfaces on each of the wedge support and die holder. Movement of the wedges toward or away from each other varies the spacing between the wedge support and die holder. The wedges can be bent in directions towards and away from each other symmetrically about a central plane to vary their separation along their length and to thereby vary the spacing of the die holder from the wedge support along their lengths so as to crown the die holder, The symmetric configuration minimizes net bending moments acting on the die holder tending to bend or twist the die holder in directions normal to the central plane.
Description
lZ34039`
This invention relates generallv to presses for metal working and more particularly to an adjustable device to compensate for the deflection of a beam supporting a die of a press used to bend a workpiece, BACKGROUN~ OF THE INVENTION
Brake presses are utilized for bending metal work-pieces. Typical brake presses compress a workpiece to be bent between elongate male and female dies typically with one of the dies on a fixed bed of the press and the other die on a movable ram, In conventional metal bending presses for bending long workpieces, such large forces are required to bend the workpiece that beams comprising the rams and bed members deflect and are bent under loading typically with greater deflection in the center of the beams then at their ends, Such deflection results in non-uniform bending of the workpiece with unequal angles of bend along its length.
Such undesired bending of the workpiece is well known and described for example in United States patent 4,016,742 to Shiokawa and United States patent 4,426,873 to Pearson, which not only describe the problem but also propose solutions thereto, One well known 601ution to compensate Eor beam deflection is to crown the ram or bed of the press. Known devices to crown the ram or bed have disadavantages, For example, one known method is to shim the die progressively from the center of its length to its etlds, Sh~mming is ~;~3'~039 1 time consuming and promo~es damage to die holders and hed.
Known devices such as in United States patent 2,456,856 to Bath have been proposed in which a plurality of wedges are selectively drawn under the die holder along its length to produce desired crowning, United States patent 4,426,873 to Pearson teaches the use of a continuous bendable wedge which is to be selectively forced under a die holder from one side to crown the center of the die holder upward, The devices of Bath and Pearson have a major disadvantage that their wedges act asymmetrically and are forced under the die holder from but one side. In urging wedges under the die holder from one side, some side-to-side bending movements are applied to the die holder and cumulative side--to-side bending movements arise in the device which are not centered about a central plane therethrough and therefore have a tendency to undesirably bend or twist the die holder from alignment about a central plane. To compensate for such undesired bending or twisting requires the bolster block to have rather undesirably large mass, SUMMARY OF THE INVENTION
Accordingly, to at least partially overcome some of these disadvantages of the pr;.or art, the present invention provides an ad~usta~lc die holder assembly which is substantially symmetrical about a central plane extending longitudinally therethrough with two wedge means, one on each side of the central plane, which can be bent to symmetrical positions about the central plane for crowning of the die holder means.
~'~3~3~
1 An object of the pre.sent invention is to provide a simplified construction for an adjustably crownable die holderr Another object is to provide a crownable die holder which can readily be adjusted to compensate for deflection in the beams comprising the ram or bed of a brake press~
A further object is to provide an adjustable bolster block which permits crowning of a die holder by bending the die holder in vertical directions while minimizing bending forces applied to the die holder in other directions Accordingly, in one of the its aspects, the pre-sent invention provides a device to compensate for deflection under loading of a beam to support an elongated die comprising elongate die holder means, elongate wedge support means, two elongate wedge means intermediate the die holder means and the wedge support means to space the die holder means from the wedge support means with one wedge means on each side of a longitudinally extending central plane centrally through the die holder means and wedge support means, cam surfaces on each wedge rneans to contact complementary camming surfaces on each of the die holder means and wedge support means which camming surEaces are locat.ed syl~letrically on their respective die holder means and wedge suppor-t means on either side of the central plane therethrough, movement of the wedge means in directions i23'~al39 1 substantially towards or away from each other varying the spacing between the die holder means and the wedge means, each wedge means bendable in directions substantially normal to the central plane to vary the distance between the two wedge means along the length of the wedge means and thereby permit the spacing of the die holder means from the wedge support means to vary along their lengths, adjustment means to bend the wedge means to desired positions symmetric with respect to each other relative to the central plane and releasably lock the wedge means in said desired symmetric positions.
The present invention provides an adjustable bolster block to be disposed between the ram or bed of a brake press and a die. The block includes a wedye support coupled to the ram or bed and a die holder to hold the die.
Two wedges are sandwiched intermediate the wedge support and die holder, one on each side of a central plane passing longitudinally through the bolster block. The wedges have cam surfaces which engage complementary camming surfaces on each of the wedge support and die holder. Movement of the wedges toward or away from each other varies the spacing between the wedge support and die holder. The wedges can be bent in directions towards and away from each other symmetrically about a central plane to vary their separation along their length and to thereby vary the spacing of the die holder from the wedye support along their lengths so as to crown the die holder. With the camming surfaces symmetrically ~Z34039 1 disposed on either side of the central plane, location of the wedges at symmetrical bent positions about the central plane bends the die holder in directions parallel to the central plane while minimizing net bending moments acting on the die holder as well as on the bolster block as a whole tending to bend or twist them in directions normal to the central plane.
BRIEF DESCRIP~ION OF THE DRAWINGS
. Further aspects and advantages of the invention will appear from the following description taken together withthe accompanying drawings in which:
Figure 1 is a schematic side view of an entire length of a bolster block in accordance with a preferred embodiment of the present invention shown with an exaggerated crowning of the die holder;
Figure 2 is a schematic cross-sectional plan view taken through section line II-II' of Figure l;
Figure 3 is a partial pictorial view looking at a segment of the bolster block of.Figure 1 from section line III-III' in Figure l;
Figure 4 is a partial cross-sectional plan view taken through the segment of the bolster block shown in F.igure 3 along section l;.ne IV-IV' shown in Figure l;
Figure 5 is a schematic cross-sectional end view through section V-V' of Figure 1 and showing add~tional components making up a typical brake press environment in which the bolster block may be used; and ~'~3~03~
1 Figures 6 to 9 are schematic cross-sectional end views through alternative embodiments of bolster blocks in accordance with the present invention.
Throughout the drawings, identical reference numerals are used to indicate similar elements.
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is made first to Figure 3 which shows a schematic pictorial view of a boister block generally designated 10 in accordance with a preferred embodiment of the present invention. Bolster block 10 has four main elements, two wedges 20 and 30, wedge support 16 and die holder 18. Wedges 20 and 30 are disposed intermediate wedge support 16 and die holder 18 to vertically space the die holder 18 from the wedge support 16~
Wedges 20 and 30 have upper cam surfaces 22 and 32, respectively, and lower cam surfaces 24 and 34, respectively.
Wedge support 16 has upwardly disposed, first camming surfaces 26 and 36 complementary to lower cam surfaces 24 and 34 of the wedges and in slidable supporting engagement therewith. Die holder 18 has downwardly disposed, second camming surfaces 28 and 38, complementary to upper cam surfaces 22 and 32 of the wedges and in slidable supporting engagement therewith.
Figure 3 shows an imaginary longitudinally extending vertical central plane 40 passing through bolster block 10.
First camming surfaces 26 and 36 on wedge support 16 are, as seen in end view symmetrically located with respect to ~ ~ 3 ~(~39 1 each other about central plane 40. Second camming surfaces 28 and 38 on die holder 18 are also symmetrical with respect to each other on either side of central plane 40.
With cam surfaces 22 and 24 of wedge 20 tapering so that the height of the wedge decreases towards central plane 40 and with wedge 30 being a mirror image of wedge 20 with cam surfaces 32 and 34 tapering towards central plane 40, on movement of the wedges toward or away from each other, the vertical spacing between wedge support 16 and die holder 18 will change. All the cam surfaces and camming surfaces are shown to be planar to assist in permitting lateral, side-to-side sliding of ~he wedges with respect to the wedge support 16 and die holder 18.
Each wedge 20 and 30 is bendable in a direction towards or away from each other, which in the case of the embodiment of Figures 1 to 5 is normal to central plane 40, so that the distance between the two wedges may vary along their lengths. Figure 2, for example in a cross-sectional plan view looking down on the wedges, shows how the wedges may be bent so as to be closer together in the middle segments of the bolster hlock then at its ends with wedges 20 and 30 symmctrical.ly about central plane 40. With the distances bctween the two wedges varying along the length of the wedges, the spacing of the die holder 18 from the wedge support 16 will accordingly vary along their lengths under loading. As seen in Figures 1 and 2, in ~he middle of the lengths where the wedges are closest together, ~Z3~039 1 the uppermost surface 42 o~ die holder 18 is spaced the greatest distance from the wedge support. Conversely, at the ends of the lengths, the wedges are furthest apart and the uppermost surface 42 of die holder 18 is spaced the least distance from wedge support 16. With wedges 20 and 30 bent to desired syrnmetrical positions about central plane 40, the die holder will be bent in a vertical direction so its upper surface 42 assumes a desired crowned profile as seen exaggerated in Figure 1.
The relative positioning of wedges 20 and 30 and resultant spacing of die holder 18 from wedge support 16 can be seen by comparing Figures 3 and 5 with the height H of the bolster block in Figure 5 being less than the height H3 in Fi.gure 3 and with the distance D5 of one wedge from central key 44 in Figure 5 being greater than the distance D3 in Figure 3.
With each wedge 20 and 30 in a symmetrical position about central plane 40 with respect to the other and with respect to wedge support 16, the die holder 18 will inherently assume a position centered about central plane 40. Thus, if a second longitudinally extending imaginary plane were presumed to extend centrally througll d.ie holder 18, when wedges 20 and 30 are centered on wedge support 16 with central plane 40 passing symrnetrically therethrough, die holder 18 will inhe~ently assume a position with the second imaginary central plane co-planar with central plane 40. ~ith wedges 20 and 30 in desired 123 ~Q39 1 symmetrical positions, the die holder is bent in a vertical direction without side-to-side bending of the die holder, Wedge support 16 is shown provided with a vertical upstanding key 44 symmetrically about plane 40 to be vertically slidably received in a complementary keyway 46 in die holder 18, Key 44 and keyway 46 assist in maintaining wedge support 16 and die holder 18 centered with respect to each other during ad~ustment of the wedges to desired posit.ions~
During loading however, wedges 20 and 30 when symmetrically located will by themselves provide for accurate centering of the die holder and wedge support, Keyway 46 has a depth that key 44 does not contact the innermost end of the keyway.
As seen in Figure 1, a plurality of sets 48 of adjustment means are provided at spaced intervals along the length of bolster block 10, One set 48 is shown in cross-sectional plan view in Figure 4. A first set screw 50 is threadably received in wedge 30 and on rotation bears against surface 52 of key 44 of wedge support 16 to urge wedge 30 away from key 44, A second set screw 54 is threadably received in key 44 and on rotation bears against surface 56 of wedge 20 to urge wedge 20 away from key 44. A bore 58 is provided through wedge 30 permitting access to set screw 54.
Bolt 60 passes through bores in wedye 30 and key 44 to be threadably received in wedge 20. By tightening bolt 60, the two wedges may be drawn together and locked in a desired position, As seen, head 62 of bolt 60 engages shoulder 64 in the enlarged outer portion of the bore in wedge 30 lZ3~039 1 To ad~ust the wedges to a desired symmetric position,with bolts 60 loosened, each set screw 50 and 54 is rotated to urge wedges 30 and 20 the desired dist~nces from each side of key 44~ Bolt 60 may then be tightened to lock the wedges in their desired positions. Each set 48 of adjustment means may be independently adjusted and locked until the wedges are bent throughout their length to provide desired crowning of die holder 189 Such adjustment may be accomplished by trial and error with test work pieces~
In the preferred embodiment, in addition to sets 48 of adjustment means, vertical locating bolts 66, 68, 70 and 72 ~ay be provided, one at each end of wedge 20 and 30 as best seen in Figures 1 and 2, As seen in Figure 5, these locating bolts extend from the wedge support 16 15 through closely tolerant bores in the wedges to be threadably received in die holder 18, The locating bolts serve to accurately locate the ends of each wedge at symmetric positions about central plane 40 as is advantageous to produce crowning~
Due to the considerable length of many bolster blocks, retaining bolts may also be provided to further assist in retaining the die holder 18 on wedge support 16 during transportation and h~nclling, Two such boLts 76 and 78 are shown in Figures 1 and 2 at intermediate positions along the length of the bolster block. As best seen in Figure 5, bolt 76 extends from a shouldered bore 79 vertically upward through key 4~ to be threadably received iZ3~39 1 in die holder 18~ Bolt 76 is loosely received in the vertical bore throu~h key 44, As well, the bolt when threaded fully into the bore in the die holder to be tightly received therei.n leaves a space 80 between its head 81 and the shou3.der 82 o bore 79 in the wedge support so that bolt 76 does not restrict vertical upward movement of die holder 16 as is required for crowning, Bolt 76 thus holds the wedge support end die holder together loosely without interfering with.use of the bolster block in crowning, The use of the bolster block in accordance with the present invention is now explained in association with Figure 5, As shown in Fi~ure 5, bolster block 10 is mounted with wedge support 16 received on a fixed bed 12 of a brake press~ While a number of different systems are known to mount the wedge support 16 to the bed, by example bed 2 is shown with a central upstanding key 83 -to be received in a keyway of wedge support lS.
Femal.e die 84 is shown mounted on die holder.18 with a central key 86 of the die 84 received in a complementary keyway on the die holder. Vertically above female die 84, a complementary male die 88 is shown mounted in a movable ram 14. Ram 14 is movable downward along central plane 40 to com-press a metal workpiece (not shown) betwecn the male and emale dies and sui:tably berld the same.
During compression of the workpiece in a typical brake press, that is, under loaded conditions, the beams comprising Eixed bed 12 and ram 14 are deflected with their ends bent downwardly more than their central positions.
lZ3~1)39 1 To compensate for this deflection~ wedges 20 and 3Q, prior to loading, are locked in desired symmetric positions with respect to central plane 40 so that die holder 18 will suitably crown or be bent in the vertical direction, yet remain straight and centered about a vertical central plane ~0 parallel to which and along which th~ compressive forces act~
In the preferred embodiment of this invention, wedges 2G and 30 are coupled together against movement toward or away from each other so that under loading,with each wedge in desired symmetric positions, each wedge applies, as compared to the other wedge, equal oppositely directed forces normal to the central plane to the die holder which forces cancel and accumulatively do not apply forces to the die holder tending to bend it normal to the central plane. This is particularly so with the bending moments normal to the central plane which are applied by one wedge to ~he die holder haYing a complementary equal and opposite bending moment which is applied by the other wedge and with both moments applied at symmetric locations on either side of the central plane. Due to the symmetry of application of bending moments about the central plane, no forces are applied to the die holder attempting to flex or bend the same other than in pure:ly vert:ical clircctions as is desired for crowning, Similarly, each wedge applies as compared to the other wedge, symmetrical equal oppositely directed forces normal to the central plane to the wedge support means which forces cancel and cumulatively do not 3L'~3~3~
1 apply forces to the wedge support tending to bend it normal to the central plane~
Figures 6 to 9 show cross-sectional end view of bolster blocks similar to that of Figures 1 to 5, varying by the angular orientation of the camming surfaces and the relative positioning or absence of keys and keyways between the wedge support and die holder.
In Figure 6, first camming surfaces 26 and 36 are angled to slope downwardly and towards the center but at a lower angle than that of second camming surfaces 28 and 38, Wedges 20 and 30 in Figure 6 as in Figure 5 taper towards central plane 40, In Figure 6 the angulation of both the first and second cam surface can assist in wedges 20 and 30 being self-centering about the central plane under loading parallel to and centered on the central plane~ Figure 6 also shows the provision of a key 44a extending from die holder 18 down into keyway 46a in wedge support 16. The wedges can be coupled to key 44a for example by a.threaaed bolt loosely received in a bore wedge 30 to permit sufficient vertical movement therein as is necessary if the bolt is to be horizontal.
Fi~ure 7 shows an crnbodiment with wedges 20 and 30 tapering away from central plane 40. ~
Figures 8 and 9 show, respectively, embodiments in which camming surfaces 26 and 2~ are symmetric about a horizontal plane disecting each wedge when the wedges are arranged symmetrically about cen-tral plane 40. ~In these embodiments, a simple horizontal bolt schematically shown as 92 may draw the wedges 20 and 30 together or force them .1'~3'~039 1 apart, The wedges~ each.of wh.ich is symmetric a~out a horizontal plane~ will tend to be self-centering~ Use merely of vertical locating bolts such as 66~ 68, 70 and 72 described in association with the ~irst embodiment at ends of each of the wedges in the embodiments of Figures 8 and 9, can assist in accurately centering the wedges although they may under loading inherently accurately self center when coupled together merely with ~olts 92~
The adjustment means to bend the wedges to desired positions symmetric wi.th respect to each other, relative to the central plane and releasably lock the wedge means in the desired position may comprise many alternative means to those illustrated in association with Figures 1 to 5 and Figures 6 to 9, For example, adjustment means could comprise a turn-buckle like structure threaded in one wedge with left~hand threads and threaded in the other wedge with right-hand threads, In the context-o~ Figure l,.the-~urn-buckle like structure may pass through a bore in the central key 44 of the wedge support, whereby turning the turn-buckle like member the wedges would be drawn together or urged apart. If the wedges of Figure 1 were merely coupled together by such turn-buckle devic:e, which may, for example, not be coupled to tho ccntral kcy 44, then even if the sets 48 o~ ad~ustment means; the locating bolts 66, 68, 70 and 72; and retaining bolts 76 and 78 were eliminated;
due to the symmetric cam and camming surfaces the wedges would under loading inherently assume symmetrical positions with respect to die holder 18. -:
--1~--:LZ34(~39 1 An advantage of the die holder assembly in accord-ance with present invention in that it permits the helght of the die ~older above the wedge support to be varied along its length~ In Figure 1, this height variation is shown as a central crowning with the height var~ing symmetrically to a central highest point~ The height may however be varied along the length as desired, for example, to crown to a high point off center as may be necessar~ to compensate for off center deflection. The height could be varied as a wave increasing and decreasin~ with length. Such a-wave form could, ~or example, provide two crowned sections and could be advantageous for bending two pieces located at longitudinally spaced locations on the die, The height may also be varied to decrease from one end to the other.
Such versatility in height variation permits the brake press to compensate for many deflection conditions and for permanent deformation of old press brakes, The bolster block in accordance with the present invention as for example shown in Figures 1 to 5 has an inherent bias to be self-centering. In repeated use of the block in bending successive work pieces, the block is repeatedly cycled between loaded and unloaded conditions.
Upon the application oE loading forces and upon removal of the loadingl the components of a bolster block may to at least a small extent. More or shift with respect to each other. In accordance with the present invention, the wedges, wedge support and die inherently are self-centering, for ~IL2~403~
1 example, due one or more of the symmetrical camming sur-fa~es, central key on the ~edge support and particular ad-justment means 48 whether the block is loaded, unloaded or being loaded or unloaded~ This inherent tendency to be self-centering assists in maintaining a work piece properly centered on the brake press, in contrast with known single wedge bolster blocks in which a single wedge is urged but~. from one side.
While the invention has been described with reference to preferred embodiments, many modifications and variations will now occur to a person skilled in the art, For a definition of the invention reference is made to the appended claims.
This invention relates generallv to presses for metal working and more particularly to an adjustable device to compensate for the deflection of a beam supporting a die of a press used to bend a workpiece, BACKGROUN~ OF THE INVENTION
Brake presses are utilized for bending metal work-pieces. Typical brake presses compress a workpiece to be bent between elongate male and female dies typically with one of the dies on a fixed bed of the press and the other die on a movable ram, In conventional metal bending presses for bending long workpieces, such large forces are required to bend the workpiece that beams comprising the rams and bed members deflect and are bent under loading typically with greater deflection in the center of the beams then at their ends, Such deflection results in non-uniform bending of the workpiece with unequal angles of bend along its length.
Such undesired bending of the workpiece is well known and described for example in United States patent 4,016,742 to Shiokawa and United States patent 4,426,873 to Pearson, which not only describe the problem but also propose solutions thereto, One well known 601ution to compensate Eor beam deflection is to crown the ram or bed of the press. Known devices to crown the ram or bed have disadavantages, For example, one known method is to shim the die progressively from the center of its length to its etlds, Sh~mming is ~;~3'~039 1 time consuming and promo~es damage to die holders and hed.
Known devices such as in United States patent 2,456,856 to Bath have been proposed in which a plurality of wedges are selectively drawn under the die holder along its length to produce desired crowning, United States patent 4,426,873 to Pearson teaches the use of a continuous bendable wedge which is to be selectively forced under a die holder from one side to crown the center of the die holder upward, The devices of Bath and Pearson have a major disadvantage that their wedges act asymmetrically and are forced under the die holder from but one side. In urging wedges under the die holder from one side, some side-to-side bending movements are applied to the die holder and cumulative side--to-side bending movements arise in the device which are not centered about a central plane therethrough and therefore have a tendency to undesirably bend or twist the die holder from alignment about a central plane. To compensate for such undesired bending or twisting requires the bolster block to have rather undesirably large mass, SUMMARY OF THE INVENTION
Accordingly, to at least partially overcome some of these disadvantages of the pr;.or art, the present invention provides an ad~usta~lc die holder assembly which is substantially symmetrical about a central plane extending longitudinally therethrough with two wedge means, one on each side of the central plane, which can be bent to symmetrical positions about the central plane for crowning of the die holder means.
~'~3~3~
1 An object of the pre.sent invention is to provide a simplified construction for an adjustably crownable die holderr Another object is to provide a crownable die holder which can readily be adjusted to compensate for deflection in the beams comprising the ram or bed of a brake press~
A further object is to provide an adjustable bolster block which permits crowning of a die holder by bending the die holder in vertical directions while minimizing bending forces applied to the die holder in other directions Accordingly, in one of the its aspects, the pre-sent invention provides a device to compensate for deflection under loading of a beam to support an elongated die comprising elongate die holder means, elongate wedge support means, two elongate wedge means intermediate the die holder means and the wedge support means to space the die holder means from the wedge support means with one wedge means on each side of a longitudinally extending central plane centrally through the die holder means and wedge support means, cam surfaces on each wedge rneans to contact complementary camming surfaces on each of the die holder means and wedge support means which camming surEaces are locat.ed syl~letrically on their respective die holder means and wedge suppor-t means on either side of the central plane therethrough, movement of the wedge means in directions i23'~al39 1 substantially towards or away from each other varying the spacing between the die holder means and the wedge means, each wedge means bendable in directions substantially normal to the central plane to vary the distance between the two wedge means along the length of the wedge means and thereby permit the spacing of the die holder means from the wedge support means to vary along their lengths, adjustment means to bend the wedge means to desired positions symmetric with respect to each other relative to the central plane and releasably lock the wedge means in said desired symmetric positions.
The present invention provides an adjustable bolster block to be disposed between the ram or bed of a brake press and a die. The block includes a wedye support coupled to the ram or bed and a die holder to hold the die.
Two wedges are sandwiched intermediate the wedge support and die holder, one on each side of a central plane passing longitudinally through the bolster block. The wedges have cam surfaces which engage complementary camming surfaces on each of the wedge support and die holder. Movement of the wedges toward or away from each other varies the spacing between the wedge support and die holder. The wedges can be bent in directions towards and away from each other symmetrically about a central plane to vary their separation along their length and to thereby vary the spacing of the die holder from the wedye support along their lengths so as to crown the die holder. With the camming surfaces symmetrically ~Z34039 1 disposed on either side of the central plane, location of the wedges at symmetrical bent positions about the central plane bends the die holder in directions parallel to the central plane while minimizing net bending moments acting on the die holder as well as on the bolster block as a whole tending to bend or twist them in directions normal to the central plane.
BRIEF DESCRIP~ION OF THE DRAWINGS
. Further aspects and advantages of the invention will appear from the following description taken together withthe accompanying drawings in which:
Figure 1 is a schematic side view of an entire length of a bolster block in accordance with a preferred embodiment of the present invention shown with an exaggerated crowning of the die holder;
Figure 2 is a schematic cross-sectional plan view taken through section line II-II' of Figure l;
Figure 3 is a partial pictorial view looking at a segment of the bolster block of.Figure 1 from section line III-III' in Figure l;
Figure 4 is a partial cross-sectional plan view taken through the segment of the bolster block shown in F.igure 3 along section l;.ne IV-IV' shown in Figure l;
Figure 5 is a schematic cross-sectional end view through section V-V' of Figure 1 and showing add~tional components making up a typical brake press environment in which the bolster block may be used; and ~'~3~03~
1 Figures 6 to 9 are schematic cross-sectional end views through alternative embodiments of bolster blocks in accordance with the present invention.
Throughout the drawings, identical reference numerals are used to indicate similar elements.
DETAILED DESCRIPTION OF THE DRAWINGS
Reference is made first to Figure 3 which shows a schematic pictorial view of a boister block generally designated 10 in accordance with a preferred embodiment of the present invention. Bolster block 10 has four main elements, two wedges 20 and 30, wedge support 16 and die holder 18. Wedges 20 and 30 are disposed intermediate wedge support 16 and die holder 18 to vertically space the die holder 18 from the wedge support 16~
Wedges 20 and 30 have upper cam surfaces 22 and 32, respectively, and lower cam surfaces 24 and 34, respectively.
Wedge support 16 has upwardly disposed, first camming surfaces 26 and 36 complementary to lower cam surfaces 24 and 34 of the wedges and in slidable supporting engagement therewith. Die holder 18 has downwardly disposed, second camming surfaces 28 and 38, complementary to upper cam surfaces 22 and 32 of the wedges and in slidable supporting engagement therewith.
Figure 3 shows an imaginary longitudinally extending vertical central plane 40 passing through bolster block 10.
First camming surfaces 26 and 36 on wedge support 16 are, as seen in end view symmetrically located with respect to ~ ~ 3 ~(~39 1 each other about central plane 40. Second camming surfaces 28 and 38 on die holder 18 are also symmetrical with respect to each other on either side of central plane 40.
With cam surfaces 22 and 24 of wedge 20 tapering so that the height of the wedge decreases towards central plane 40 and with wedge 30 being a mirror image of wedge 20 with cam surfaces 32 and 34 tapering towards central plane 40, on movement of the wedges toward or away from each other, the vertical spacing between wedge support 16 and die holder 18 will change. All the cam surfaces and camming surfaces are shown to be planar to assist in permitting lateral, side-to-side sliding of ~he wedges with respect to the wedge support 16 and die holder 18.
Each wedge 20 and 30 is bendable in a direction towards or away from each other, which in the case of the embodiment of Figures 1 to 5 is normal to central plane 40, so that the distance between the two wedges may vary along their lengths. Figure 2, for example in a cross-sectional plan view looking down on the wedges, shows how the wedges may be bent so as to be closer together in the middle segments of the bolster hlock then at its ends with wedges 20 and 30 symmctrical.ly about central plane 40. With the distances bctween the two wedges varying along the length of the wedges, the spacing of the die holder 18 from the wedge support 16 will accordingly vary along their lengths under loading. As seen in Figures 1 and 2, in ~he middle of the lengths where the wedges are closest together, ~Z3~039 1 the uppermost surface 42 o~ die holder 18 is spaced the greatest distance from the wedge support. Conversely, at the ends of the lengths, the wedges are furthest apart and the uppermost surface 42 of die holder 18 is spaced the least distance from wedge support 16. With wedges 20 and 30 bent to desired syrnmetrical positions about central plane 40, the die holder will be bent in a vertical direction so its upper surface 42 assumes a desired crowned profile as seen exaggerated in Figure 1.
The relative positioning of wedges 20 and 30 and resultant spacing of die holder 18 from wedge support 16 can be seen by comparing Figures 3 and 5 with the height H of the bolster block in Figure 5 being less than the height H3 in Fi.gure 3 and with the distance D5 of one wedge from central key 44 in Figure 5 being greater than the distance D3 in Figure 3.
With each wedge 20 and 30 in a symmetrical position about central plane 40 with respect to the other and with respect to wedge support 16, the die holder 18 will inherently assume a position centered about central plane 40. Thus, if a second longitudinally extending imaginary plane were presumed to extend centrally througll d.ie holder 18, when wedges 20 and 30 are centered on wedge support 16 with central plane 40 passing symrnetrically therethrough, die holder 18 will inhe~ently assume a position with the second imaginary central plane co-planar with central plane 40. ~ith wedges 20 and 30 in desired 123 ~Q39 1 symmetrical positions, the die holder is bent in a vertical direction without side-to-side bending of the die holder, Wedge support 16 is shown provided with a vertical upstanding key 44 symmetrically about plane 40 to be vertically slidably received in a complementary keyway 46 in die holder 18, Key 44 and keyway 46 assist in maintaining wedge support 16 and die holder 18 centered with respect to each other during ad~ustment of the wedges to desired posit.ions~
During loading however, wedges 20 and 30 when symmetrically located will by themselves provide for accurate centering of the die holder and wedge support, Keyway 46 has a depth that key 44 does not contact the innermost end of the keyway.
As seen in Figure 1, a plurality of sets 48 of adjustment means are provided at spaced intervals along the length of bolster block 10, One set 48 is shown in cross-sectional plan view in Figure 4. A first set screw 50 is threadably received in wedge 30 and on rotation bears against surface 52 of key 44 of wedge support 16 to urge wedge 30 away from key 44, A second set screw 54 is threadably received in key 44 and on rotation bears against surface 56 of wedge 20 to urge wedge 20 away from key 44. A bore 58 is provided through wedge 30 permitting access to set screw 54.
Bolt 60 passes through bores in wedye 30 and key 44 to be threadably received in wedge 20. By tightening bolt 60, the two wedges may be drawn together and locked in a desired position, As seen, head 62 of bolt 60 engages shoulder 64 in the enlarged outer portion of the bore in wedge 30 lZ3~039 1 To ad~ust the wedges to a desired symmetric position,with bolts 60 loosened, each set screw 50 and 54 is rotated to urge wedges 30 and 20 the desired dist~nces from each side of key 44~ Bolt 60 may then be tightened to lock the wedges in their desired positions. Each set 48 of adjustment means may be independently adjusted and locked until the wedges are bent throughout their length to provide desired crowning of die holder 189 Such adjustment may be accomplished by trial and error with test work pieces~
In the preferred embodiment, in addition to sets 48 of adjustment means, vertical locating bolts 66, 68, 70 and 72 ~ay be provided, one at each end of wedge 20 and 30 as best seen in Figures 1 and 2, As seen in Figure 5, these locating bolts extend from the wedge support 16 15 through closely tolerant bores in the wedges to be threadably received in die holder 18, The locating bolts serve to accurately locate the ends of each wedge at symmetric positions about central plane 40 as is advantageous to produce crowning~
Due to the considerable length of many bolster blocks, retaining bolts may also be provided to further assist in retaining the die holder 18 on wedge support 16 during transportation and h~nclling, Two such boLts 76 and 78 are shown in Figures 1 and 2 at intermediate positions along the length of the bolster block. As best seen in Figure 5, bolt 76 extends from a shouldered bore 79 vertically upward through key 4~ to be threadably received iZ3~39 1 in die holder 18~ Bolt 76 is loosely received in the vertical bore throu~h key 44, As well, the bolt when threaded fully into the bore in the die holder to be tightly received therei.n leaves a space 80 between its head 81 and the shou3.der 82 o bore 79 in the wedge support so that bolt 76 does not restrict vertical upward movement of die holder 16 as is required for crowning, Bolt 76 thus holds the wedge support end die holder together loosely without interfering with.use of the bolster block in crowning, The use of the bolster block in accordance with the present invention is now explained in association with Figure 5, As shown in Fi~ure 5, bolster block 10 is mounted with wedge support 16 received on a fixed bed 12 of a brake press~ While a number of different systems are known to mount the wedge support 16 to the bed, by example bed 2 is shown with a central upstanding key 83 -to be received in a keyway of wedge support lS.
Femal.e die 84 is shown mounted on die holder.18 with a central key 86 of the die 84 received in a complementary keyway on the die holder. Vertically above female die 84, a complementary male die 88 is shown mounted in a movable ram 14. Ram 14 is movable downward along central plane 40 to com-press a metal workpiece (not shown) betwecn the male and emale dies and sui:tably berld the same.
During compression of the workpiece in a typical brake press, that is, under loaded conditions, the beams comprising Eixed bed 12 and ram 14 are deflected with their ends bent downwardly more than their central positions.
lZ3~1)39 1 To compensate for this deflection~ wedges 20 and 3Q, prior to loading, are locked in desired symmetric positions with respect to central plane 40 so that die holder 18 will suitably crown or be bent in the vertical direction, yet remain straight and centered about a vertical central plane ~0 parallel to which and along which th~ compressive forces act~
In the preferred embodiment of this invention, wedges 2G and 30 are coupled together against movement toward or away from each other so that under loading,with each wedge in desired symmetric positions, each wedge applies, as compared to the other wedge, equal oppositely directed forces normal to the central plane to the die holder which forces cancel and accumulatively do not apply forces to the die holder tending to bend it normal to the central plane. This is particularly so with the bending moments normal to the central plane which are applied by one wedge to ~he die holder haYing a complementary equal and opposite bending moment which is applied by the other wedge and with both moments applied at symmetric locations on either side of the central plane. Due to the symmetry of application of bending moments about the central plane, no forces are applied to the die holder attempting to flex or bend the same other than in pure:ly vert:ical clircctions as is desired for crowning, Similarly, each wedge applies as compared to the other wedge, symmetrical equal oppositely directed forces normal to the central plane to the wedge support means which forces cancel and cumulatively do not 3L'~3~3~
1 apply forces to the wedge support tending to bend it normal to the central plane~
Figures 6 to 9 show cross-sectional end view of bolster blocks similar to that of Figures 1 to 5, varying by the angular orientation of the camming surfaces and the relative positioning or absence of keys and keyways between the wedge support and die holder.
In Figure 6, first camming surfaces 26 and 36 are angled to slope downwardly and towards the center but at a lower angle than that of second camming surfaces 28 and 38, Wedges 20 and 30 in Figure 6 as in Figure 5 taper towards central plane 40, In Figure 6 the angulation of both the first and second cam surface can assist in wedges 20 and 30 being self-centering about the central plane under loading parallel to and centered on the central plane~ Figure 6 also shows the provision of a key 44a extending from die holder 18 down into keyway 46a in wedge support 16. The wedges can be coupled to key 44a for example by a.threaaed bolt loosely received in a bore wedge 30 to permit sufficient vertical movement therein as is necessary if the bolt is to be horizontal.
Fi~ure 7 shows an crnbodiment with wedges 20 and 30 tapering away from central plane 40. ~
Figures 8 and 9 show, respectively, embodiments in which camming surfaces 26 and 2~ are symmetric about a horizontal plane disecting each wedge when the wedges are arranged symmetrically about cen-tral plane 40. ~In these embodiments, a simple horizontal bolt schematically shown as 92 may draw the wedges 20 and 30 together or force them .1'~3'~039 1 apart, The wedges~ each.of wh.ich is symmetric a~out a horizontal plane~ will tend to be self-centering~ Use merely of vertical locating bolts such as 66~ 68, 70 and 72 described in association with the ~irst embodiment at ends of each of the wedges in the embodiments of Figures 8 and 9, can assist in accurately centering the wedges although they may under loading inherently accurately self center when coupled together merely with ~olts 92~
The adjustment means to bend the wedges to desired positions symmetric wi.th respect to each other, relative to the central plane and releasably lock the wedge means in the desired position may comprise many alternative means to those illustrated in association with Figures 1 to 5 and Figures 6 to 9, For example, adjustment means could comprise a turn-buckle like structure threaded in one wedge with left~hand threads and threaded in the other wedge with right-hand threads, In the context-o~ Figure l,.the-~urn-buckle like structure may pass through a bore in the central key 44 of the wedge support, whereby turning the turn-buckle like member the wedges would be drawn together or urged apart. If the wedges of Figure 1 were merely coupled together by such turn-buckle devic:e, which may, for example, not be coupled to tho ccntral kcy 44, then even if the sets 48 o~ ad~ustment means; the locating bolts 66, 68, 70 and 72; and retaining bolts 76 and 78 were eliminated;
due to the symmetric cam and camming surfaces the wedges would under loading inherently assume symmetrical positions with respect to die holder 18. -:
--1~--:LZ34(~39 1 An advantage of the die holder assembly in accord-ance with present invention in that it permits the helght of the die ~older above the wedge support to be varied along its length~ In Figure 1, this height variation is shown as a central crowning with the height var~ing symmetrically to a central highest point~ The height may however be varied along the length as desired, for example, to crown to a high point off center as may be necessar~ to compensate for off center deflection. The height could be varied as a wave increasing and decreasin~ with length. Such a-wave form could, ~or example, provide two crowned sections and could be advantageous for bending two pieces located at longitudinally spaced locations on the die, The height may also be varied to decrease from one end to the other.
Such versatility in height variation permits the brake press to compensate for many deflection conditions and for permanent deformation of old press brakes, The bolster block in accordance with the present invention as for example shown in Figures 1 to 5 has an inherent bias to be self-centering. In repeated use of the block in bending successive work pieces, the block is repeatedly cycled between loaded and unloaded conditions.
Upon the application oE loading forces and upon removal of the loadingl the components of a bolster block may to at least a small extent. More or shift with respect to each other. In accordance with the present invention, the wedges, wedge support and die inherently are self-centering, for ~IL2~403~
1 example, due one or more of the symmetrical camming sur-fa~es, central key on the ~edge support and particular ad-justment means 48 whether the block is loaded, unloaded or being loaded or unloaded~ This inherent tendency to be self-centering assists in maintaining a work piece properly centered on the brake press, in contrast with known single wedge bolster blocks in which a single wedge is urged but~. from one side.
While the invention has been described with reference to preferred embodiments, many modifications and variations will now occur to a person skilled in the art, For a definition of the invention reference is made to the appended claims.
Claims (15)
- Claim 1 continued ...
adjustment means to bend the wedge means to desired positions symmetric with respect to each other relative to the central plane and releasably lock the wedge means in said desired symmetric positions. - 2, A device as claimed in claim 1 wherein with the wedge means in said desired symmetric positions under loading, the wedge means cumulatively do not apply bending moments to either the die holder means or the wedge support means normal to the central plane.
- 3. The device of claim 1 wherein the wedge means are coupled together against movement towards or away from each other so that under loading with each wedge means in said desired symmetric position, each wedge means applies, as compared to the other wedge means, equal, oppositely directed forces normal to the central plane to the die holder means and equal, oppositely directed forces normal to the central plane to the wedge holder means so that the wedge means cumulatively do not apply forces to either the die holder means or the wedge support means tending to bend them normal to the central plane.
- 4. A device as claimed in claim 2 wherein said loading comprises loading forces applied parallel to and centered on said central plane.
- 5. A device as claimed in claim 3 wherein the wedge means are coupled together and said adjustment means releasably lock the wedge means in said desired symmetric positions against movement relative to each other,
- 6. A device as claimed in claim 5 wherein the wedge means are coupled together by each being coupled to the wedge support means,
- 7. The device claimed in claim 5 wherein the wedge means are coupled together by each being coupled to the die holder means.
- 8. The device claimed in claim 3 wherein said wedge means taper in width decreasing towards the center plane,
- 9. The device claimed in claim 8 wherein said cam surfaces and said camming surfaces are flat, planar surfaces.
- 10. A device as claimed in claim g wherein said camming surfaces on the wedge support means are normal to said central plane.
- 11. A device as claimed in claim 3 wherein said wedge support means has a central longitudinally extending key to be slidably received in a central longitudinally extending keyway of said die supporting means to assist in maintaining said wedge support means and said die holder means centered with respect to each other about said central plane.
- 12. A device as claimed in claim 11 wherein said adjustment means comprise sets of first, second and third threaded coupling means each substantially normal to the central plane and located at similar positions along the length of the wedge means, the first threaded means coupling one wedge means-to the other wedge means to urge the same away from or toward each other, the second threaded coupling means coupling one wedge means to the key of the wedge support means to urge the same away from or toward each other, the third threaded coupling means coupling the other wedge means to the key of the wedge support means to urge the same away from or towards each other.
- 13. The device of claim 10 wherein said die holder means has one of a key or a keyway symmetrical about said central plane to receive a complementary keyway or key on said die.
- 14. The device of claim 1 which comprises an improved bolster block adapted to be interposed between a die of a brake press and its associated press brake bed.
15. An adjustable die holder assembly for a brake press or the like comprising:
elongate wedge support means receivable on a press brake bed, said wedge support means having a longitudinally extending first central plane therethrough, Claim 15 continued ...
elongate die holder means, two elongate wedge means disposed intermediate the die holder means and the wedge support means to space the die holder means from the wedge support means with one wedge means on each side of the first plane, each wedge means having first planar cam surfaces in supporting, sliding engagement with complementary first planar camming surfaces on the wedge support means and second planar cam surfaces in supporting, sliding engagement with complementary second, planar camming surfaces on the die holder means, the first camming surfaces on the wedge support means being symmetrical about the first plane and the second camming surfaces on the die holder means being symmetrical about a longitudinally extending second central plane through the die holder means wherein with the wedge means located at symmetric positions on either side of the first plane, the die holder means and wedge support means are relatively positioned that the first plane and the second plane are co-planar, movement of the wedge means towards or away from each other in directions substantially normal to the first plane varying the spacing between the die holder means and the wedge support means, each wedge means being flexible in a direction substantially normal to the first plane to vary the distance of the wedge means from the first plane along the length of the wedge means and thereby vary the spacing of the die holder - Claim 15 continued ...
means from the support means along their length, adjustable coupling means coupling the wedge means together against movement towards or away from each other and adjustable to bend the wedge means to desired positions with respect to each other on either side of the first plane by varying the distance of one wedge means from the other, said coupling means releasably locking the wedge means in said desired positions.
1. A device to compensate for deflection under loading of a beam to support an elongated die comprising:
elongate die holder means, elongate wedge support means, two elongate wedge means intermediate the die holder means and the wedge support means to space the die holder means from the wedge support means with one wedge means on each side of a longitudinally extending central plane centrally through the die holder means and wedge support means, cam surfaces on each wedge means to contact complementary camming surfaces on each of the die holder means and wedge support means which camming surfaces are located symmetrically on their respective die holder means and wedge support means on either side of the central plane therethrough, movement of the wedge means in directions sub-stantially towards or away from each other varying the spacing between the die holder means and the wedge means, each wedge means bendable in directions substantially normal to the central plane to vary the distance between the two wedge means along the length of the wedge means and thereby permit the spacing of the die holder means from the wedge support means to vary along their lengths,
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000485726A CA1234039A (en) | 1985-06-27 | 1985-06-27 | Adjustable bolster block |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000485726A CA1234039A (en) | 1985-06-27 | 1985-06-27 | Adjustable bolster block |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1234039A true CA1234039A (en) | 1988-03-15 |
Family
ID=4130868
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000485726A Expired CA1234039A (en) | 1985-06-27 | 1985-06-27 | Adjustable bolster block |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1234039A (en) |
-
1985
- 1985-06-27 CA CA000485726A patent/CA1234039A/en not_active Expired
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