CA1268925A - Method and apparatus for performing a substantially flat blank of an open clamp - Google Patents

Abstract

Abstract The invention provides an open preformed clamp made of band material and adapted to be mechanically interconnected near free ends thereof that are spaced apart a slight distance in the axial direction whereby the clamp has a helical overlapping configuration approximating the circular configuration of the clamp when installed about an object to be fastened on a relatively fixed generally circular part. The invention also relates to a method of making such a clamp.

Description

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The present invention relates to a method for preforming a substantially flat blank of an open clamp adapted to be mechanically interconnected near free ends thereof into a circular clamp having a configuration at least approximately the configuration of the clamp when installed, as well as to a preformed open clamp.
Basically, two types of clamps are commercially avail-able; namely, so-called endless or permanently closed types of clamps and so-called open types of clamps adapted to be ;;
mechanically interconnected near the free ends thereof.
My prior U.S. Patents 2,614,304 and 3,082,498 (Figures 1 and 2) disc'ose clamps of the endless type which are made from tubular ~aterial. In the alternative, endless or closed-type clamps are known which have their ends permanently connected, for example, by spot-welding or in a rivet-like manner (U.S. Patent 3,286,314). U.S. Patents 3,475,793; 3,321,811; 4,222,155 and 3,~82,498 (Figures 3 and 4) disclose various types of open clamp structures to be mechanically interconnected near their free ends by engagement of hooks into apertures. Other types oE open clamps are so-called screw-type clamps whose ends are drawn together by a screw or bolt. Still other open-type clamp structures utilize a toggle mechanism to draw toget~her the free band ends. Both types of clamp ; 25 ~ ~structures are frequent1y made from~band materiall normally stored in the form of a coil. One method for making a permanently clos~ed clamp is~d1sclosed in~the U.S. Patent 3~021,631 to Kennedy, accordlng to~which the band is Eed to forming dies where it~is punched out in such a shape as to 30 ~permit permanent locking of the band in the subsequent : ~ ~ steps. More particularly, in this patent, after the punch-ing operation, the band is brought into engagement with ~.

il3925 a mandrel of predetermined shape, is pressed into the final shape by coacting die members which cause a tongue portion of the punched-out band to pass through an opening, whereupon the tongue portion is bent back upon itselE and is thereafter tightly crimped or pressed into the locking position forming the closed or endless clamp structure. The clamps, whether in the permanently locked condition or wi~h thelr ends open, were normally preformed into circular shape in the course of their manufacture and were shipped to the customer in this circular shape. Though bending of the band material by hand had been suggested previously in my prior U.S. Patent 2,847,742, it was an accepted, generally unquestioned practice to manufacture the various types of open clamp structures with generally circular configuration to assure proper installation thereof by the user, for example, on the assembly line, particularly as difficulties are likely to be encountered in the installation of open clamps, whether of completely flat configuration or of flat configuration over only a major part .
of the clamp band as disclosed in U.S. Patent 3,235,925 to Gerhardt et al. Hence, these types of open clamp structures were normally manufactured and shipped to the customer in preformed condition, frequently in quasi-endless condition, i.e., with the hooks of the circular band already engaged in apertures. If these types of clamps were to be installed axially~, the operator merely slipped these quasi-endless clamps over the object to be fastened and then proceeded~to tigh~ten the clamp, for example r by the closing of a so-called "Oetiker"* ear. On the other hand, if these quasi-endless ` types of clamps were to be instaIled radially, the clamps had ~ to~be reopened, placed~about the object to be fastened and re-connected at the free ends, whereupon the cIamp was tig~htened, for example, again by contracting a so-called "Oetiker't ear.

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~;~92,5 With large-quantity use of these types of open clamps in mass production applications, such as on the assembly line of the automotive industry~ a reduction of the overall costs in the use of these clamps whose raw material costs were fixed, could be achieved only by a reduction in the cost of manufacture, handling and use thereof. Apart from the fact that the prior art types of open clamp having a generally circular configuration required a different machine for each clamp size, the maximum rate of production thereof was limited by the operating step requiring the greatest amount of time, which turned out to be the bending of the clamps into the more or less circular shape.
Recognizing the shortcomings and drawbacks of the prior art, I proposed the use of a preforming machine to permit manufacture and shipment of the punched-out clamps in flat blank condition in my prior U.S. patent 4,425,781 issued January 17, 1984 (Canadian patent 1,194,682 issued October 8, 1985). According to this prior patent, the two ends were each deformed into predetermined configuration so as to facilitate assambly to the clamp over the object to be fastened by the preformed shape of the clamp resulting from deformation and spring-back action of the resilient band material. The present invention represents a further improve-ment over the apparatus and method disclosed in my prior patent in that the clamp is preformed from its flat blank ;
condition into circular conflguration having predetermined diametric dimensions substantially corresponding to the desired diametric dimension of the cIamp when installed over ~: :
~ the object to be fastened but prior to tightening thereof.
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Accordingly, the principal object of the present invention is to overcome the aforementioned shortcomings and drawbacks encountered in the prior art and to provide a method and apparatus by means of which signiican~t savings can be attained in the use of open A
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clamps without jeopardizing their proper installation and their holding ability.
The underlying problems are solved according to the present invention by providing a method of preforming a substantially flat pre-cut blank of a band material adapted to form an individual open clamp provided with means for a mechanical interconnection near free ends thereof and operable to be mechanically interconnected by said means with said free ends overlapping to form a clamp having a generally`circular configuration corresponding at least approximately to the configuration of the clamp when installed about an object to be fastened onto a relati~ely ~: fixed, generally circular part, compr;sing the steps of providing a pre-cut generally flat elongated blank having means for mechanical interconnection near leading and trailing free ends of said blanlc, Eeeding said elongated blan~ along its length into a number of rollers thereby preorming the thus-fed substantially flat blank into ~:
permanent generally helical shape~ corresponding to said 20. generally clrcular configuration, with the mechanical interconnection means near the free e~nds bearing a helica1 ;~
overlapping relationsh;p to each other with~the leading end axially spaced from the trail~ing~end relative to the:~
circular configuration to facili~ate subsequent assemb1y 25:~ of~-the thus~preformed clamp over~the~objeot~to~be fastened when~said~mèchanic~:al~interconnecting means are :~
inte~connected.~
The inventi~on also consists of an open preormed clamp mad~e~of band~material~and adapted~to be:mechanica]ly inter-:30~ : connected near ~fr~ee~ends~ther:eof~that are spaced apart a :~
s:1ight distance ln~the axial~dlrectlon ~hereby the clamp 1 : has a helical overlapping confi~uration approximatin~ the : -4-~: : :' 1".~ ~

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circular configuration of the clamp when installed about an object to be fastened on a relatively fixed generally circular ~art.
According to another ~eature of the present invenkion, the flat blank of the clamp can also be provided with any desired indicia or markings, such as date of installation, trademark of user of the clamp and the like,~by the use of a stamping mechanism which is located ahead of the deforming mechanism and in which the flat blank is stamped or embossed. According to the present invention, the stamping and deforming mechanisms are controlled by an automatic control system which causes the feed rollers to be actuated for a short period of time when the leading ~:
~ end of the blank encounters a sensor so as to position the blank correctly for the stamping operation in a predetermined part o~ the blank while the drive of the :~ : feed~rollers is interrupted, and resuming ~4~
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the operation of the feed rollers upon completion of the st2mping operation to thereafter complete the preforming operation of the clamp into generally circular configuration. Since the diameter of the preformed clamp must be so c:hosen that its ends overlap, the preforming operation also deforms the clamp so that the free ends thereof in the completely preiormed, generally circuLar configuration are spaced a small axial distance from one another in order to avoid interference in the preforming operation by the leading end which would otherwise seek to reenter the feeding roller pair.
According to still a further feature o.' the preaent lnvention, the feed rollers may be so shaped that the lateral edges of the blank are bent outwardly as viewed in the radial direction of the preformed clamp so as to lessen the likelihood of damage of the hose material when the clamp is installed.
These and other objects, features and advantages of the`
; present invention will become more apparent from the following ~:
descrLption when taken in COnneCtLOn with the accsmpanying drawlng~which shows,~for purposes of illustration:only, one 20~ embodiment in accordance with the present invention, and wherein ~:
Figure 1 is a front elevational view of a preforming machine~
in accordance with the present invention; ::
Figure 2 is a~right side elevational view of the preforming machlne of Figure~
25~ : Figure 3 is a~top~plan view of~the preforming machine of Fi~sures l and 2;
; Flgure 4 is a~partlal~s~ide:elevatLonal viewt on an enlarged scale,~of the feed rollers~ in~a~preferred embodiment of the machine in accordance with the present inventlon;
Figure 5 is a schematic diagram;of the pneumatic control system used in the pre~orming machine of the present inventlon;

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Figures 6 - 8 are schematic views illustrating the operation of the machine in accordance with the present invention;
Figures 9 and 10 are, respectively, plan and side elevational views of a clamp with which the machine of the present invention can be used; and ~ igure 11 is a perspective view of a preformed clamp in accordance with the present invention.
Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts~
and more particularly to Figures 1 to 3, the preforming and stamping machine in accordance with the present invention is mounted on a base plate generally designated by reference numeral lS whose front face 16 is visible in Figure 1. The preforming machine in accordance with the present invention ~is essentially consists of two parts; namely, a preforming machine assembly generally designated by reference numeral 20 which performs the preforming operation of the fIat blank, as : ~: : : ` `
shown, for example, in Figures 9 snd 10, into a circular open-type clamp, as shown, far example, in Figure 11, and of a 20~ stamping machine assembly generally designated by reference numeral 50 for stamping the flat blank with appropriate indicia, such as,~date, trade name or trademark of the user, part number and~the li~ke.
The~preformLng machine assembly 20 includes a housing 21 25 ~ `cont~aLning~the necess~ary gearing~ (not~;shown) of conventional~
construction to~drive the pai~r of rollers 22 and 23 from the~
drlve motor 4~0 whlch is preferably~a;comprsssed aLr~motor of known type. ~The~roller~s~22 and 23 are driven ~y drive shafts 32 and 33, respectively (Figure 4). The rolLers 22 and 23, wkich in their simPl99tform are provided with flat outer suraces, are :

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12~;892~i -thereby of such dimensions that tha gap formed therebetween correaponds to the thickness of the material used for the flat blank so that the oppositely rotating rollexs 22 and 23 will feed the blank through the machine as long as the blank is in contact with the rollers. In a preferred en~odiment of the prasent invention, the outer circumferential surfaces of the rollers 22 and 23, instead of being flat, axe bevel}ed on each side (Figue 4), as indicated by reference n~erals 22' and 23' 50 that the lateral edges 101' of the preformed clamp 101 (Fig~re 11) are bent in the radially outward direction at an angle, for example, of 45 in order to minimize the danger of damage to a hose-like material to be fastened by the clamp. A freely rotatable guide roller 24 is so located in the rectilinear feed path of the flat blank toward and through the feed rollers 22 and 23 that it will deform the flat blank into circular configuration when the flat 15 blank, positively fed by the rollers 22 and 23, encounters the outer surface of the deforming roller 24. The roller 24 is thereby freely rotatably mounted on a support arm 25 whose ~; lower end is slotted at 25' for engagement over a threaded tightening member 26 which, when loosened, serves at the same tlme as ~ivot shaft for the support arm 25. The radius of the preformed clamp can thus be adjusted by movement of the support arm in the~direction of its slot 25' as well as in the pivotal d~Lrection. An adjustLnq~screw 27 held in positfon by a lock nut 28, holds the support~arm 25 in~position against the ~d;e~ormLng forces~exerted; thereon~by~the blank as it is forced ; through the~preforming machLne assembIy by the feed rollers 22 and 23.~ The adjusting screw 27 thereby assists the tightening : ~ ~
member 26 in holding the support arm 25 in proper position.

Since the open ends of the preformed clamp are intended to overlap (Figure 11~ to permit closing thereoi by engagement ~26~g25 c the hooks 102 in apertures 103 ~Figure 9), an L-shaped deflection plate generally designated by reference numeral 30 is provided which causes an additional deformation of the clamp in such a manner that the free ends of the preformed clamp are spaced a small dlstance from one another in the axial direction (Figure 11) so that the clamp assumes a "helical overlapping configuration", i.e. a configura~tion wherein the free ends will overlap when the band!material is deformed to overcome the axial spacing. In that way, the leading deformed edge of the circular clamp will not interfere with completion of the preEorming operatîon by seeking to re-enter the gap between the feed rollers 22 and 23. The L-shaped deflection plate 30 which is mounted on the base plate 15 with a horizontal leg 31a thereof, includes a second leg 31b in the form of a flat plate which extends at an acute angle ~ (Figure 8) upwardly and outwardly with respect to a vertical plane perpendicular to the axes oE the shafts 32 and 33 and contain-ing the rectilinear feed path of a blank through the machine.
Additionally, the deforming plate 31b is also inclined outwardly at an acute angle R (Figure 3) with respect to this plane in a direction opposite the rectilinear feed movement of the blank~to~the feed rollers 22 and 23 so that ~he free lead-ing end of the preformed clamp is~axially spaced from the `
tralling~free end (Figure 11) due to the Eact that no deforming -action is exerted by the plate 31b: on the trailing end once it leaves~the feed rollers~21~and 22. ~A guide~member 29,~for e~ample, an L-shaped rod,~ is~thereby~so mounted on the housing 21~that its shorter leg 29' extends into the area of the inlet ~, :
of~the~feed rollers 22 and 23 to prevent the blank material ;30~from str~aying laterally from~its~ rectilinear feed path and instead to confine the blank to the area of the gap formed between the feed rollers 22 and 23.
Attached to the housing 21 is addi~tionally a small block-like member 34 which provides rectilinear guidance for the flat blank, ~,- ., ~J ~ ~,b 12~8~25 for example, by the provision of an appropriately shaped slot in a die secured in member 34. A sensor element 35 is displaceably~
mounted within the housing 21 along the rectilinear path of the flat blan~ shortly ahead of the gap between the feed rollers 22 5 and 23. The sensor element 35 is thereby so constructed and arranged by conventional means that it will be displaced by the arrival of the full width of the flat blank to thereby :
initiate operation of the control cycle of the machir.e in accordance : ~ with the present invention, as will be described more fully hereinafter. The sensor element 35 may be, for example, a cylindrical member rotatable about a vertical axls and displaceable in a direction parallel to ~hats 32 and 33. The sensor element 35 thereby actuate a valve 75 by way of a suita~le linkage (not shown) mounted within housing 21.
The stamping machine assembly generally designated by reference numeral 50 includes two lateral housing walls 51 and 52 which are held in proper bolted-together position by the use of spacer members (not shown). The stamping machine assembly : further includes a relatively fixed support member 54 provided with a groove-like channel whose upper blank-suppo:rt surface 54' :~ is flush with and forms part of the rectilinear feed path of the flat ~blank, and a pivotal pressure~ember 55 havinq a lower~flat sta~m~ing surface which:is thereby~so~constructed and pivotally suppo;rted~by~known means that ~ts~stamping surface will be~
~2~5~ parallel~to~ the upper support surface 5~4' when it comes into Atact with the upper surface~of~ the blank.~ Secured to the~
pivotal stamping member 55~is an:approximately L-shaped~arm 62 which is:adapted to~be engaged~by a roller-liXe memb r~63 fastened to a disk-like actuating member 64 eccentrically connected to the disk-like driving m ber 65 which LS coaxlal with and driven ~689~5 by a larger gear 66. To provide a large speed-reduction arranyement, as required to produce the ~ecessary stamping force, the motor ~haft 56' of the compressed air motor 56 drives the gear 66 by way of a first speed-reducing gear arrangement, ~or example, a chain and sprocket gearing arrange-ment generally designated by reference numeral 57 whose smaller gear 57a non-rotatably connected with motor shaft 56' drives a larger gear 57b mounted on shaft 58 while a second speed-reduction is provided by the meshing engagement of a small gear 59 non-rotatably mounted on shaft 58 w~th the much larger gear 66 rotating in unison with the disk-like driving members 64 and 65 supported on shaft 61. Rotation of the motor 56 in the cloc~wise direction, as viewed in Figure 2, will thus cause rotation of the disk-like members 64 and 65 in the counterclockwise direction ~o as to cause the roller-like member 63 to pivot the pressure member 55 in the cloc~wise direction by engagement with arm 62 and thereby causin~ the stamping press to close. Rotation of the compressed air motor 56 in the opposite, counterclocXwise ::
direction, as viewed in Figure 2,;will then oause reopening of the stamping press by rotation of the~pressure member 55 in the opposite direction which is assisted by a spring 67 urging the pressure member in the opening direction. Suitable guide means formed, for example, by appropriately shaped dies ~ or~;the like ~not~shown)~may al~o~be provided ln the lateral ; walls~51~and 52 ~to assure rectilinear guldance of the flat blank through th~e machine.~ ~
A control arm 70~Figures 2 and~5) which is~rotated by compressed air motor 56 by way o~a sha~t ~63 (Figures 3 and 5) ~30 and by way of a speed-reduction gearing, if neoessary, is :~ : . .

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rotatably arranged within houslng 121 and is operable to be rotated to and fro between a first position in which it engages the actuating member 71' of a valve 71 and a second position in which it engages the actuating member 72' of a valve 72 during closing and opening of t~e stamping pres~.
The pneumatic control system of the present invention, illustra~ed in Figure S, additionally includes a control valve 76 for controlling operation of the pneumatic motor 40 as well as a delay valve 77 and a control valve 78 connected with the delay valve 77 by way of a further valve 79, for purposes to be explained more fully herein-after. The control valve 78, in turn, controls the operation of the compressed air motor 56 by way of the valves 71 and 72 which are each opened by enyagement of the control arm 70 ~ with the respective actuating ~e~ber 71' and 72' as the control reachea the corresponding end position. The valve 71 thereby controls rotation of the motor 56 in the clockwise direction,~ ;
as viewed in Figure 2, while valve 72 controls~rotation thereof ln the counterclockwise direction. ~Adjustable throttle members 73 and 74 are interconnected in the lines ~supplying compressed air to the motor 56 so as to enable d-ustm~nt~of he~speed of operation thereof.

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The ~operation o~ the stamping and preforming machine in ;5~ aocordance with the~present Lnv~ntLon~wlll ~ow be described.
At~fLrst, a~flat blànk~is inserted by the operator ~Lnto the~maohine~through~the~guide (not shown) in the lateral walI

51, through~the~opened~stamplng~press~S4, 55 through the guide (not shown) in the lateral wall 52 and ~hrough the suide in the ~: .

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~26~925 block-like member 34 in such a manner that the full width of the leading free end of the flat blank comes in contact with the sensor element 35. In case the flat blank is intended to form a stepless clamp and there:fore includes a tong~ portion 107, as described in my U.S. patent 4,315,348, the sensor element 35 will not be actuated by the narrower tonyue portion but will be actuated only by the }eading edge of the full-width blank at which tlme the tongue portion is already between the feed rollers 22 and 23. The actuation of the sensor element 35 will operate the valve 75 by way of a linkage, indicated only schematically in Figure 6 in dash lines, thereby opening the norma11y closed valve 7~ so as that compressed air from the compressed air supply line 80 will flow by way of a line 80', through the now open valve 75 and by way of a fur~her branch line 80'' to the control input of the valve ~::15 76 by:way of the now-~pen valve 71 which is opened at that:time : by ensagement of:the control arm 70 with actuating member 71'.
Control arm 70 is in its end position in which the stamping press:is fully opened, i.e., the pivotal member 55 thereof is::
rotated into its open position. As a result ~hereof,:the valve 76 is opened so ~hat compressed air will be supplied from line .
80 by way~of~branch llne 80 ":' and through the:now-opened : valve 76 t~o:~the compressed:air-motor 40 which starts to rotate the~:feed:~rollers~ 2:2 and 23 thereby causing the flat blank lOl to~be~advanced~as~long~as motor 40 rotates. ~Openlnq of the 25~ valve 75 will~also apply~compressed~air to the: inputs of~
delay;valve~77 by~way of branch lLne 80'~. However~delay valve 77 will delay for ~a predetermlned period of time, the opening~thereof and therewith the applicatLon of compressed air to the control input of valve 78 so as to delay ope~ing of:

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the valve 78 and therewith application of compressed air from the supply line 80 by way of branch line 80''' and line 81 to the hydraulic motor 56. During the predetermined delay, the motor 40 drives the ~eed rollexs 22 and 23 so as to advance ~he flat blank by a certain distan~e to assure stamping thereof in the desired part (Figure 6). As soon as the valve 78 opens the connection between branch line 80''' and line 81 the motor 56 and with it the control arms 70 start to rotate in the clockwise direction thereby causing the previously opened valve 71 to close which in turn causes closure of valve 76 and stoppage of the pneumatic motor 40. ~hus upon actuation o~ the sensor 35, the compressed air motor 40 will initially cause feed of the blank by the rollers 22 and 23 for such length of time until the control arm 70 starts to rotate after the expira.tiono~ the predetermined delay by control valve 77 and disengages ~rom the actuating mem~er 71'. Eowever, : while motor 40 is now stopped, motor 56 will continue to rotate in~the clockwise direction to close the stamping press ~ and ultimately to ~tamp the stopped blank until control arm 70 comes into engagement with the actuating member 72' which causes the valve 78 to close the connection between branch llne 80''' and line 81 and instead o open the connection from branch line 80''' to line~82. As~ a result thereof the motor 56 and the~ewith:the control arm 70 will atart to rotate in the : counterclockwise direct:ion, a~ter compl~tion of the:stamping opératLon which is~termlnated when the control arm 70:reaches .
its~ end position where~it comes lnto engagement w.th the~
: actuating me~ber 72'. The valve;s 78 and 79 are thereby so : ~ ~ constructed and interconnected that once the control arm 70 ~;~30 opens the valve 72 by ensagement with its actuating member 72', thereby applying comprassed air to the secand control input o~

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-` ~L26~ 25 the valve 78 and shifting the same, the hydraulic motor 56 will continue to operate in the counterclockwise direction for a predetermined length of time to permit the control arm 70 to reach again its starting position corresponding to the fully open position of the stamping press, in which valve 71 is opened up again by engagement of the control arm 70 with actuating member 71'. As a result thereof, the motor 40 will start to rotate again for such length of time until the sensor 35 is released, which will happen when the trailing end of the flat blank has passed beyond the sensor 35. In the meantime rotation of motor 40 will cause the feed rollers 22 and 23 to feed the blank through the machine (~'igures 7 and 8) until completion of the preforming oper-ation resulting in the preformed clamp as shown in Figure 11. The various valve elements are of commercially avail-able type forming no part of the present invention so that a detailed description thereof is dispensed with for the , : sake of brevity. i;:~:~ Of course, the machine in accordance with the present invention can also be used only as preforming machine by omitting the stamping machine assembly part 50 thereof. :~
In that case, it is only necessary to connect the valve 75 :~ directly with the valve 76 to control operation of the ; motor:40.
Whlle the machine of the present i~nvention:can be used wi~th~any~number~of clamps~that can be~stamped out as flat blanks, a:clamp with pressed-out tool engaging embossment~s :
108~and 109, as dlsclosed~ln my U.S. patent~4,492,004 ;~
issued J:anuary 8, 1985, offers particular:~advantages in i certa~ln applications, where the absence of any:pro]ectlng ;;
part such as an 'IOetike~r"* ear or~the bent out ends : *rrrade Mark ,: :

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9 2t~ 25 of a screw-type clamp are important. However, by appropriate minor modifications in the machine providing recesses where required, the present invention can also be used to preform screw-type clamps or "Oetiker"*~ear type clamps from the punched-out rectilinear shape into the preformed circular shape. Consequently, the term "flat blank" is used herein to describe the fact that the band material as such is not curved but remains in substantially rectilinear condition though it already includes teeth or hooks as well as possibly an ear and in case of a stepless clamp, the tongue and recess, all of which are formed in the band material during the stamping out operation of the flat blank.
The machine of the present invention thus permits to ship to the customer clamps, such as axle sleeve clamps, in straight (flat) condition which can be inserted into the machine in such straight or flat condition by the customer so as to preform the same just prior to installation on the assembly line. For example, the operator on the assembly :
- line inserts the straight (flat) clamp into the machine.
The machine then automatically initiates the start of a fully automatic operating cycle in response to the insertion ~of the clamp to stamp the clamp with the desired indicia and to preform the clamp into circular shape of any desired diameter, whereby the completely preEormed and stamped clamp ;w1th its edges bent up falls automaticnlly out of the machine. ~uring this operat~ing~cycle, the operator Installs th~e~previously preformed~clamp and;thus loses no time while waitlnq for completion of the automat1c operating cycle.

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~26~3~25 Heretofor~, axle boots or axle sleeves were fastened by round, ring-like clamps, made from a rou.nd wire formed into the shape of a ring, whose ends were butt-welded.
The welded place had to be cleaned and sanded to provide a smooth surface, whereupon the round wire material was rolled flat. After subsequent surface treatment, the thus obtained ring was placed over the axle sleeve and thereaf~er was shrunk to the predetermined diameter by the use of a special machine. Apart from high costs, this prior art approach required the complete disassembly of the axle and the use of a new axle slee~e in case of needed repairs since removal of the shrunk-on ring frequently destroyed the axle sleeve or axle boot.
In addition to eliminating the drawbacks of the afore-; 15 mentioned prior art approach, the present invention also entails significant cost advantages as regards pac~ing, shipping, storing and handling of clamps, for example, for use with axle sleeves. More specifically, if the same axle ~sleeve clamps of standard size are delivered to the customer in round condition, i.e., preformed into circulsr shape, the costs for packaging, labor and shipping as well as storing would ;
; be ahout 18 times the costs for the same clamp lf shipped in straight (flat) condltLon~and preformed when used only on ths assembly line. Of course the~cost saving factor may vary ~ according to the~si2e of the clamp.
In order to~permit~ msnual op~eratLon of the stamping machL`ne~a~ssembly~snd o~the preforming machine assembly, it is only~necessary to shape the projecting end of shaft~S5' and of shaft 32 for engagement with a complement~ry key o 30~ polygonal~shape.
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. :', , '~ . ' ': ' ~26~89Z5 While I have shown and described on~y one embodLment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art.
For example, in lieu of the pneumatic control system, also an electric or electronic control system may be used, though the pneumatic control system is particularly advantageous from a safety and efficiency point of view. Additionally, the angle of the bent-up edges lQl' may also be chosen within wide limits to suit particular needs. Consequently, I do not wish to be limited to the details shown and described herein but intend to cover all modi~ications and changes as encompassed by the scope o~ the appended claims.

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Claims (11)

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

1. A method of preforming a substantially flat pre-cut blank of a band material adapted to form an individual open clamp provided with means for a mechanical interconnection near free ends thereof and operable to be mechanically interconnected by said means with said free ends overlapping to form a clamp having a generally circular configuration corresponding at least approximately to the configuration of the clamp when installed about an object to be fastened onto a relatively fixed, generally circular part, comprising the steps of providing a pre-cut generally flat elongated blank having means for mechanical interconnection near leading and trailing free ends of said blank, feeding said elongated blank along its length between a number of rollers thereby preforming the thus-fed substantially flat blank into permanent generally helical shape corresponding in axial view to said generally circular configuration, with the mechanical interconnection means near the free ends bearing a helical overlapping relationship to each other with the leading end axially spaced from the trailing end relative to the circular configuration to facilitate subsequent assembly of the thus preformed clamp over the object to be fastened when said mechanical interconnecting means are interconnected.

2. A method according to claim 1, further comprising the step of bending up the lateral edges of the blank in a generally radially outward direction with respect to the circular configuration of the clamp.

3. A method according to claim 1, further comprising the step of marking the blank with predetermined information while the blank is still flat.

4. An open preformed clamp made of band material and adapted to be mechanically interconnected near free ends thereof which bear a helical overlapping relationship to each other and are spaced apart a slight distance in the axial direction of the helix whereby the clamp haw a helical overlapping configuration approximating the circular configuration of the clamp when installed about an object to be fastened on a relatively fixed generally circular part.

5. An open clamp according to claim 4, wherein the clamp includes outwardly extending hooks near an inner band end adapted to engage into apertures near an outer band end.

6. An open hose clamp according to claim 5, in which the clamp has lateral edge portions extending outwardly at an acute angle to the band material between said edge portions.

7. An open hose clamp according to claim 5, in which the inner and outer band ends include further means to avoid any discontinuity or step in the inner surface of the clamp adapted to engage with the object.

8. An open hose clamp according to claim 7, wherein said further means includes a tongue-like portion at the inner band end, and a step-like recess means in the outer band end for receiving the tongue-like portion.

9. An open hose clamp according to claim 7, further comprising means enabling tightening of the hose clamp about the object to be fastened.

10. An open hose clamp according to claim 9, wherein said means enabling tightening includes at least one deformable ear.

11. An open hose clamp according to claim 9, wherein said means enabling tightening includes tool-engaging surfaces of the band material movable together in an approximately circumferential direction.