Clamp for holding sheet-like objects

Information

  • Patent Grant
  • 6286662
  • Patent Number
    6,286,662
  • Date Filed
    Thursday, January 27, 2000
    24 years ago
  • Date Issued
    Tuesday, September 11, 2001
    23 years ago
  • Inventors
  • Original Assignees
  • Examiners
    • Valenza; Joseph E.
    Agents
    • Alston & Bird LLP
Abstract
The invention relates to a clamp (10) for holding sheet-like objects, having a support (12) on which a clamp tongue (20) is fixed. A clamping jaw (32) is stored in a guide slot (30) in the support (12) in such a way that it can move both in and against the direction of closing (S). When the clamping jaw (32) moves from open position (34) in closing direction (S), the clamp end (42) is displaced along the path of movement (46), until it rests against the clamp tongue (20) or an adjacent object. As the clamping jaw (32) continues to move in closing direction (S), the clamp end is driven back from the path of movement (46), and a clamping force for holding the object is formed as a result of the elasticity of the clamping jaw (32).
Description




BACKGROUND OF THE INVENTION




The present invention relates to a clamp for holding flat objects as they move along a path travel.




A clamp of the generic type, designed in the manner of a pair of tongs, is disclosed in Swiss Patent No. 569 197 and in the corresponding U.S. Pat. No. 3,948,551. It has a clamping tongue which is permanently arranged on a holding part. A clamping jaw can be pivoted about an axis extending at right angles to the clamping tongue, from an open position into a clamping position, in which it forms a clamping gap with the clamping tongue. The clamping tongue and the clamping jaw can be moved relative to each other in the extent of the clamping gap, away from each other in the open position and toward each other into their clamping position. This makes it necessary for the clamp to be rotated through 90° out of and into the area defined by the object during the opening and closing operations. Simultaneous rotation of the entire clamp and the movement of the clamping jaw relative to the clamping tongue are therefore necessary which, in addition to the space requirement during gripping and releasing an object, requires complicated control. On the other hand, this known clamp has particular advantages. It is self-locking and self-retaining, it adds virtually nothing to the thickness of the flat objects and there is consequently space for it both in an interleaved formation of the objects and in the case of buffering or stacking of the objects—with a virtually constant space requirement. Furthermore, it has such a low weight that, when necessary, it can be carried and held by the object itself.




It is an object of the present invention to provide a clamp of the generic type which, while maintaining the advantages of the known clamp, is simpler to handle.




SUMMARY OF THE INVENTION




The above and other objects and advantages of the present invention are achieved by the provision of a clamp which comprises a supporting part, a clamping tongue fixed to the supporting part, a clamping jaw moveably mounted on the supporting part for movement between an open position separated from the clamping tongue and a clamping position in which a free end of the clamping jaw forms with the clamping tongue a clamping gap adapted to engage and hold a flat article therebetween, and wherein during movement from the open position toward the clamping position, the free end of the clamping jaw moves along a movement path which forms an acute angle with the clamping tongue and during continued movement after encountering an article resting on the clamping tongue the clamping jaw is resiliently deflected out of the path of movement in a direction transverse to the clamping tongue so as to produce a clamping force on the article.




Rotating the clamp according to the invention during opening and closing is no longer necessary. It is simple in construction, inexpensive to produce and extremely simple to handle. Furthermore, the clamping jaw is held in the clamping position by self-locking; locking elements are not needed. The slim construction of the clamp enables the buffering of the objects held by the clamp in the smallest possible space, while maintaining the separation of the objects; that is to say each object is gripped individually and can thus be handled individually. Furthermore, the clamp can be opened when adjacent clamps are resting on one another in a buffer.











BRIEF DESCRIPTION OF THE DRAWINGS




The invention will now be explained in more detail with reference to an exemplary embodiment illustrated in the drawing, in which, in purely schematic form:





FIG. 1

shows, in plan view, a clamp according to the invention in the open position;





FIG. 2

shows, in side view, the clamp shown in

FIG. 1

in the closed position;





FIG. 3

shows, in a section along the line III—III in

FIG. 1

, the clamp shown there in the open position;





FIG. 4

shows, in side view, part of an apparatus having a large number of clamps according to

FIGS. 1

to


3


arranged one behind another, a printed product being fed to each of the clamps;





FIG. 5

shows, in an identical illustration to that in

FIG. 4

, the part of the apparatus shown there with a clamp during the closing operation;





FIG. 6

shows, in an identical illustration to that in

FIG. 5

, the clamp shown there in the clamping position in order to hold the printed product;





FIG. 7

shows a further part of the apparatus shown in

FIGS. 4

to


6


with a clamp holding a printed product at the beginning of the opening operation;





FIG. 8

shows the part shown in

FIG. 7

of the apparatus with a partially opened clamp;





FIG. 9

shows, in an identical illustration to that in

FIGS. 7 and 8

, the clamp shown there in the open position;





FIG. 10

shows a further part of the apparatus shown in

FIGS. 4

to


9


, having a large number of clamps arranged one behind one another, which each hold a printed product and rest on one another for the purpose of buffering;





FIG. 11

shows, in plan view and partly sectioned along the line XI—XI of

FIG. 12

, a drive apparatus for the clamps; and





FIG. 12

shows the drive apparatus shown in

FIG. 11

in plan view.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




The clamp


10


shown in

FIGS. 1

to


3


has an essentially box-shaped supporting part


12


. As viewed in the longitudinal direction of the supporting part


12


, guide tabs


14


are integrally molded on its two ends and are intended to engage in the guide rails


16


, which have a C-shaped cross section and are open toward each other. As a result, the clamp


10


can be displaced in a sliding manner in the guide rails


16


.




On one side face


18


of the supporting part


12


there rests a flat, essentially rectangular, clamping tongue


20


, which is fixed to the supporting part


12


by means of suitable fixing means


22


, for example screws or rivets. The side face


18


lies in a plane extending at right angles to the longitudinal direction of the guide rails


16


, so that the clamping tongue


20


projects transversely to the guide rails


16


, beyond these and the supporting part


12


, in the manner of a cantilever. As shown in particular by

FIGS. 2 and 3

, the clamping tongue


20


is bent about a bending line


24


extending parallel to the longitudinal direction of the supporting part


12


, so that the free end


20


′ of the clamping tongue


20


lies approximately in a plane which is defined by that face of the supporting part


12


which has a rectangular cross section and which is located opposite the side face


18


. In addition, the clamping tongue


20


has a triangular aperture


26


in its part projecting beyond the supporting part


12


, in order to save weight. Adjacent to its free end


20


′, the clamping tongue


20


is provided with two adhesive covering strips


28


on its side which is located radially on the inside as viewed in relation to the bend.




The supporting part


12


has a guide gap


30


, through which there passes a flat, essentially rectangular, bent clamping jaw


32


. The latter can be moved from an open position


34


, shown in

FIGS. 1 and 3

, into a clamping position


36


, shown in

FIG. 2

, by being displaced in the closing direction S.




The clamping jaw


32


is bent in the manner of a segment of a circular cylinder about an axis extending parallel to the longitudinal direction of the supporting part


12


, and is guided on the supporting part


12


in such a way that the clamping tongue


20


is located on the radially inner side of the clamping jaw


32


. The guide gap


30


is shaped so as to correspond to the curvature of the clamping jaw


32


.




From its free end


32


′, facing the clamping tongue


20


, the clamping jaw


32


is provided with an approximately triangular cutout


38


, by which means two clamping limbs


40


of the clamping jaw


32


are formed, which, at their end region adjacent to the free end


32


′, are bent over, in the direction opposite to the bending of the clamping jaw


32


, to form a clamping foot


42


. In clamping position


36


, the clamping feet


42


form a clamping gap


44


with the clamping tongue


20


.




In the open position


34


, the clamping jaw


32


is located in a position in which the clamping feet


42


are located at the supporting part


12


. When the clamping jaw


32


is moved from the open position


34


in the closing direction S, the clamping feet


42


move along a circular movement path


46


which intersects the clamping tongue


20


at an acute angle α. The movement path


46


is a circular path, whose center is located on the axis of the bend in the clamping jaw


32


and whose radius corresponds to the distance from the axis to the clamping jaw


32


. In the exemplary embodiment shown, the angle α is approximately 30°. However, it can also be smaller or larger; preferably, however, it is less than 45°.




When the clamp


10


is closed in the closing direction S, the clamping feet


42


move along their movement path


46


until they come to rest on the adhesive covering strip


28


or on a flat object resting on the clamping tongue


20


. During onward movement in the direction of arrow S, the clamping feet


42


slide along the outer side, facing them, of the flat product or the adhesive covering strip


28


in the direction of the free end


20


′ of the clamping tongue


20


, as a result of which the clamping feet


42


are deflected out of the movement path


46


which they would otherwise follow further. Since the clamping jaw


32


is produced from intrinsically resilient material, for example from spring-steel sheet, and is guided in the guide gap


30


so that it cannot give way transversely to the latter, the clamping feet


42


are forced back resiliently as a result, by which means a clamping force K is produced which presses the flat object onto the clamping tongue


20


and, in particular, the adhesive covering strips


28


. Because of the acute angle a, no force component, or only a small force component, is able to act on the clamping jaw


32


counter to the closing direction S. This force component is readily absorbed by the frictional force in the guide gap


30


, so that the clamp


10


is self-retaining in the clamping position


36


.




At the end


48


opposite the clamping feet


42


, the clamping jaw


32


is provided with lateral projections


50


and bent in the manner of a tube. The projections


50


are intended to interact with an opening element, in order to displace the clamping jaw


32


from the clamping position


36


into the open position


34


, counter to the closing direction S.




The supporting part


12


comprises a supporting element


52


having a recess


54


, into which there is inserted a wedge element


56


, which engages with a retaining tab


58


behind the clamping tongue


20


and in this way is retained in the recess


54


. The supporting element


52


and the wedge element


56


bound the guide gap


30


.





FIGS. 4

to


6


show part of an apparatus


60


for processing printed products


62


, such as newspapers, magazines and the like. A transfer section


64


is shown in which, by means of clamps


10


, printed products


62


fed by a belt conveyor


66


are accepted for onward transport. In the transfer section


64


, the guide rails


16


extend in the vertical direction and the clamps


10


, which are arranged immediately one behind another and resting on one another, are moved continuously forward from bottom to top in a conveying direction F. As viewed in the conveying direction F, the clamping tongues


20


of the clamps


10


trail the clamping jaws


32


. The free end


20


′ of the clamping tongues


20


faces the belt conveyor


66


, which is intended to transport the printed products


62


in the feed direction Z in an interleaved formation, in which each printed product


62


rests on the subsequent one. On the side which is opposite the belt conveyor


66


, as referred to the guide rails


16


, there is arranged a closing apparatus


68


for the clamps


10


. The latter has an endless flexible drive member


70


, which is driven so as to circulate in the direction of arrow A at a speed v, which is greater than the speed v


f


at which the clamps


10


are moved. Arranged on the flexible drive member


70


, at intervals one behind another, are cams


72


which are each intended to interact with the end


48


of one clamping jaw


32


.




The feed speed of the belt conveyor


66


and the speed v


f


with which the clamps


10


are moved are coordinated with each other in such a way that each clamp


10


is fed a printed product


62


. As emerges from

FIG. 4

, in each case one clamping tongue


20


engages under the printed product


62


projecting beyond the end of the belt conveyor


66


and lifts this end in conveying direction F. Approximately at the same instant as the relevant clamping tongue


20


touches the printed product


62


, a cam


72


of the closing apparatus


68


strikes the end


48


of the relevant clamping jaw


32


and displaces the latter from the open position


34


in the closing direction S; this is as a result of the difference between the speed v of the cams


72


and the speed v


f


of the clamps


10


.





FIG. 5

shows that instant during the closing operation of the clamp


10


at which the clamping foot


32


comes into contact with the printed product


62


. Since, however, because of its inherent stability, the printed product


62


is not yet resting flat on the clamping tongue


20


, said product can be pushed still further in the feed direction Z into the clamping mouth, until it is brought to rest on the adhesive covering strip


28


by the clamping foot


42


. From this moment, during the onward movement of the clamping jaw


32


in the closing direction S, the clamping limb


40


, which is lengthened in the process, is stressed in the manner of a leaf spring, as a result of which a clamping force builds up, with which the printed product


62


is held by the clamp


10


for onward transport, as shown in FIG.


6


. It goes without saying that the adhesive action of the adhesive covering strips


28


on the printed product


62


is greater than the sliding friction between the clamping feet


42


and the printed product


62


. If necessary, the clamping foot


42


can be provided with a sliding covering. As is further revealed by

FIG. 6

, the clamps


10


are in each case in the closed position


36


when they reach the end of the closing apparatus


68


.





FIGS. 7

to


9


show a further part, a discharge section


74


, of the apparatus


60


already mentioned in conjunction with

FIGS. 4

to


6


. In the discharge section


74


shown, the guide rails


16


extend in the horizontal direction, and the clamps


10


are directed in the downward direction in order to transport the printed products


62


in a hanging position. The clamps


10


are moved in conveying direction F. As they enter the discharge section


74


, the clamping jaws


32


are in the clamping position


36


and each hold a printed product


62


in the clamping gap


44


formed by them and the relevant clamping tongue


20


. A wedge-shaped opening wing


76


is arranged on the two guide rails


16


. In the course of the movement in conveying direction F, the two projections


50


of the relevant clamping jaw


32


come to rest on the opening wing


76


and, in the course of the onward movement of the clamp


10


, are pulled in the opening direction, counter to the closing direction S.

FIG. 7

shows the instant at which the projections


50


on a clamp


10


touch the opening wing


76


. In the course of the onward movement, the clamping jaw


32


is pulled upward, as a result of which the clamping force K is reduced.

FIG. 8

shows the instant at which the clamping foot


42


releases the printed product


62


, so that the latter can be transferred downward to the next processing station. The clamping jaw


32


is subsequently moved completely into the open position


34


, as

FIG. 9

shows. The clamp


10


is ready to accommodate a printed product


62


again. The frictional relationships in the guide gap


30


are adequate to keep the clamping jaw


32


in the open position


34


.





FIG. 10

shows a buffer section


78


of the apparatus


60


. This section is located, for example, between the transfer section


64


shown in

FIGS. 4

to


6


and the discharge section


74


shown in

FIGS. 7

to


9


. In the buffer section


78


, the guide rails


16


likewise extend in the horizontal direction and the clamps


10


, each occupied by a printed product


62


, rest on one another. This figure shows, in particular, that the clamps


10


, as viewed in the longitudinal direction of the guide rails


16


, are designed to be extremely slim, so that they add very little in comparison with the thickness of the printed products


62


which can be held by them. As a result, a high packing density can be achieved in the buffer section.





FIGS. 11 and 12

show a drive section


80


of the apparatus


60


in elevation and plan view. In the drive section


80


, the bottom


82


of the guide rails


16


, which have a C-shaped cross section, is removed. However, the lateral limbs


84


which are connected to each other by the bottom


82


in the other sections also extend continuously through the drive section


80


, in order to guide the clamps


10


. The supporting parts


12


of the clamps


10


engage with their guide tabs


14


in the guide rails


16


, and their end faces


86


are intended to interact in the drive section


80


with driver elements


88


of a drive apparatus


90


; a drive apparatus


90


is assigned to each guide rail


16


. One of the drive apparatuses


90


, which is of symmetrical construction and arrangement, will be described below. A large number of driver elements


88


are arranged on a chain


92


, which is intrinsically closed and is guided around two sprockets


94


which have parallel axes and are spaced apart from each other in the direction of the guide rails


16


. One of these sprockets


94


is driven so as to circulate in conveying direction F by means of a drive unit (not shown). The active conveying run


96


of the chain


92


extends parallel to the relevant guide rail


16


and, with respect to the latter, is arranged in such a way that the corresponding driver elements


88


engage between the limbs


84


in the guide rail


16


and rest with frictional contact on the end faces


86


of the supporting parts


12


of the clamps


10


. A pressure and guide rail


98


arranged between the sprockets


94


ensures that the pressing force is maintained.




As can also be seen from

FIG. 12

, the clamps


10


can be moved freely in the guide rails


16


outside the drive apparatus


90


, so that they can assume a different distance from one another.




A drive section


80


can overlap, for example, with a transfer section


64


or a discharge section


74


in order to move the clamps


10


in the conveying direction F in these sections.




It is also conceivable for the clamping jaws to be designed to be flat and for the clamping shoe


42


to be moved along a rectilinear movement path as the clamp is closed and opened. The movement path forms an acute angle with the clamping tongue in this case, too.




It is of course possible for the clamps


10


and for the apparatus


60


to be designed differently.




Clamps according to the invention are suitable, for example, for use in apparatuses such as are disclosed in WO Patent Applications PCT/CH97/00200 and PCT/CH97/00201.




Printed products


62


were mentioned as an example of flexible, flat objects in conjunction with the exemplary embodiment shown. However, the clamps


10


according to the invention are also suitable for holding stiff, flat objects or flat objects of different flexibilities.




The objects can have different thicknesses. In the exemplary embodiment shown, as the thickness increases, the clamping force K also becomes greater.




The clamping tongue can be of intrinsically resilient design and, for this purpose, can be produced from spring-steel sheet, for example. Finally, it would also be conceivable to design the clamping tongue to be resilient and the clamping jaw to be flexurally rigid.



Claims
  • 1. A clamp for holding flat articles comprisinga supporting part, a clamping tongue fixed to the supporting part, a clamping jaw moveably mounted on the supporting part for movement between an open position separated from the clamping tongue and a clamping position in which a free end of the clamping jaw forms with the clamping tongue a clamping gap adapted to engage and hold a flat article therebetween, and wherein during movement from the open position toward the clamping position, the free end of the clamping jaw moves along a movement path which forms an acute angle with the clamping tongue and during continued movement after encountering an article resting on the clamping tongue the clamping jaw is resiliently deflected out of the path of movement in a direction transverse to the clamping tongue so as to produce a clamping force on the article.
  • 2. The clamp as defined in claim 1 wherein the clamping jaw is formed of an inherently resilient material.
  • 3. The clamp as defined in claim 2 wherein the clamping tongue includes an adhesive-like surface on a side thereof facing the clamping jaw for engaging an article received thereon.
  • 4. The clamp as defined in claim 2 wherein the acute angle is less than about 45 degrees.
  • 5. The clamp as defined in claim 2 wherein the clamping tongue extends outwardly from the supporting part in a longitudinal direction, and wherein the movement of the clamping jaw between the open and clamping positions is along a generally longitudinal direction.
  • 6. The clamp as defined in claim 5 wherein the clamping jaw is arcuately curved along its longitudinal length, and wherein the clamping tongue is positioned on the radially inner side of the clamping jaw.
  • 7. The clamp as defined in claim 6 wherein the supporting part includes a guide gap which slideably receives the clamping jaw, and wherein the guide gap has a curvature which corresponds to the curvature of the clamping jaw.
  • 8. The clamp as defined in claim 6 wherein the free end of the clamping jaw is bent to form a clamping foot.
  • 9. The clamp as defined in claim 6 wherein the clamping tongue and the clamping jaw are each formed of a sheet material.
  • 10. An article transport apparatus comprisinga plurality of clamps for holding flat articles, with each clamp comprising a supporting part, a clamping tongue fixed to the supporting part, a clamping jaw moveably mounted on the supporting part for movement between an open position separated from the clamping tongue and a clamping position in which a free end of the clamping jaw forms with the clamping tongue a clamping gap adapted to engage and hold a flat article therebetween, and wherein during movement from the open position toward the clamping position, the free end of the clamping jaw moves along a movement path which forms an acute angle with the clamping tongue and during continued movement after encountering an article resting on the clamping tongue the clamping jaw is resiliently deflected out of the path of movement in a direction transverse to the clamping tongue so as to produce a clamping force on the article, a guide rail for supporting the clamps for movement along a path of travel, a delivery conveyor for delivering an article onto the clamping tongue of each of the clamps as the clamps move past a transfer location along the path of travel, and while the clamping jaws are in the open position, a closing device positioned along the path of travel immediately downstream of the transfer location for moving the clamping jaw of each of the clamps to its clamping position and so that the articles are engaged and held between the clamping tongue and the clamping jaw of the associated clamp, and a discharge device mounted along the path of travel downstream of the closing device for moving the clamping jaw of each of the clamps to its open position so as to release the article therefrom.
Priority Claims (1)
Number Date Country Kind
1613/97 Jul 1997 CH
PCT Information
Filing Document Filing Date Country Kind 102e Date 371c Date
PCT/CH98/00180 WO 00 1/27/2000 1/27/2000
Publishing Document Publishing Date Country Kind
WO99/01367 1/14/1999 WO A
US Referenced Citations (7)
Number Name Date Kind
2716910 Guerinet Sep 1955
3662875 Salomon May 1972
3948551 Reist Apr 1976
3986745 Langguth Oct 1976
4007824 Reist Feb 1977
4036356 Reist Jul 1977
5489093 Morehead, III Feb 1996
Foreign Referenced Citations (7)
Number Date Country
569 197 Nov 1975 CH
552 330 Jun 1932 DE
23 03 424 Aug 1974 DE
0 643 001 Mar 1995 EP
1 123 381 Aug 1968 GB
WO 9803420 Jan 1998 WO
WO 9803421 Jan 1998 WO