Patent Application
20120227256
The present invention relates to fastener dispensing apparatus having a fastener feeding device for feeding fasteners into the path of a punch of the apparatus, the punch being drivable to dispense a fastener and optionally insert it into a workpiece.
The term “fastener” is used here to include, for example, rivets, screws, slugs and other types of fasteners. The term “punch” is used here to include any appropriate component of a fastener insertion apparatus which inserts such fasteners into a workpiece.
A fastener insertion apparatus, such as a punch riveter, is commonly used in the construction of a wide variety of workpieces, such as white goods and automobiles. The fastener insertion apparatus includes a reciprocally translating punch and a feeding device which feeds fasteners into the path of the punch. Such fastener insertion apparatus are often used in large scale continuous production lines over long periods of time. It is therefore desirable that the fastener insertion apparatus is equipped with a feeding device capable of reliably providing a large supply of fasteners into the path of the punch.
It is desirable that a feeding device functions reliably so as to avoid errors, such as a fastener not being supplied to the fastener insertion apparatus when expected or a fastener being incorrectly fed into the path of the punch. Such errors can result in a halt in production, in the fastener insertion apparatus incorrectly fastening workpieces together, or in damage to either the workpieces or the fastener itself.
A halt in production is a costly delay in itself. However, damage to the feeding device or the fastener insertion apparatus can be a particularly problematic cause of delays because the machines must be taken offline so as to be repaired. In the case of a production line this requires shutting down production for a time, at a significant cost. The feeding device and fastener insertion apparatus should therefore function reliably and robustly in order to reduce the likelihood of delays due to the need to repair or replace them.
Fasteners are often fed into fastener insertion apparatus supported in an elongate flexible carrier such as a tape. The tape comprises a number of spaced apart holes along its length, into which fasteners are inserted and is fed into the path of the punch so that, the punch sequentially drives each fastener from the tape and inserts it into a workpiece.
In such a tape-fed fastener insertion apparatus, the feeding device feeds the tape through the fastener insertion apparatus so that each fastener in the tape becomes aligned with the path of the punch and is inserted by the punch into a workpiece which is being fastened. A common solution to the problem of timing movement of the tape during a fastener insertion cycle is to use the reciprocal movement of the punch to drive the feeding device.
In one such example, a punch-driven rivet insertion apparatus described in a PCT patent application published as WO 93/09918 incorporates a guide bush, within which a punch travels, a punch-driven index wheel which feeds a tape of rivets through the apparatus, and a nose piece which is pressed against a workpiece into which a rivet is to be inserted. During a rivet insertion cycle, the punch emerges from an end of the guide bush and travels through a cavity defined through the centre of the index wheel. After the punch passes through the cavity, it drives a rivet from the tape, through the nose piece and into the workpiece. As the punch drives the rivet into the workpiece, a rearward portion of the punch engages the index wheel, causing the index wheel to rotate. Rotation of the index wheel by the punch causes the wheel to index along the tape. The index wheel is biased by a torsion spring so that, when the punch retracts, the index wheel rotates back to its original position. The return motion of the wheel feeds the tape further through the apparatus, feeding the next rivet on the tape into the path of the punch. In some commercial embodiments the function of the torsion spring is fulfilled by a stripper spring, which is primarily used in the apparatus to bias the nose piece away from the punch as the punch is retracted at the end of a rivet insertion cycle. This double function of the stripper spring is achieved by providing a push rod between the stripper spring and the index wheel.
One problem with the above described apparatus is that the punch is unsupported as it travels through the cavity defined in the index wheel. As a result, should the punch drive an incorrectly aligned rivet against the nose piece, shear stresses may be imparted to the punch that can potentially cause damage.
A further problem is that, as the punch retracts, it can catch the next rivet on the tape “lifting” the rivet from the tape sufficiently to dislodge it. Thus, when that rivet is fed into the path of the punch, and subsequently punched, it is misaligned and causes a jam, or even damage to the apparatus. This is particularly a problem with short rivets as they can be lifted out of the tape carrier completely.
It is an object of the present invention to obviate or mitigate at least some of the problems outlined above. An alternative object is to provide for improved or alternative fastener insertion apparatus
According to a first aspect of the present invention there is provided fastener dispensing apparatus for dispensing fasteners comprising: a body in which a punch path is defined; a punch at least partially within the punch path, the punch being reciprocally moveable between a retracted position and an advanced position in which it extends from an end of the punch path in order to drive a fastener towards a dispensed position; a fastener feed path extending transverse to the punch path, the fastener feed path being arranged for receipt of an elongate carrier of fasteners; and a fastener feeding device for feeding the elongate carrier along the fastener feed path such that fasteners are sequentially brought into alignment with the end of the punch path, the fastener feeding device comprising an actuator moveable relative to the body by the reciprocal movement of the punch and at least one engagement member for engaging the elongate carrier or a fastener in the carrier, the at least one engagement member being moveable relative to the body in response to movement of the actuator.
The movement of the punch, which is typically in a rectilinear direction, between the retracted and advanced positions thus effects feeding of the elongate carrier so as to bring the next fastener into line with the punch path. The movement of the at least one engagement member relative to the body in which the punch path is defined provides for apparatus that is reliable and compact.
The actuator may be provided within the body and may be moveable by contact with a part of the punch at an appropriate point in its reciprocation in the punch path. The actuator may be coupled directly or indirectly to the at least one engagement member. The actuator may extend at least partially into the punch path.
The fastener feed path may be defined at least in part by a surface of the body. This is advantageous in that the surface of the body limits the movement of fasteners in the elongate carrier relative to the apparatus and relative to the elongate carrier. This ensures that fasteners in the carrier are fed into the path of the punch in a reliable fashion. For example, the surface substantially prevents lifting or hooking of the fasteners by the punch during retraction, thus improving reliability of performance of the fastener insertion apparatus. The fastener feed path may extend through the body or may extend at one end.
In one embodiment, the at least one engagement member is reciprocally moveable between a retracted position in which it is disengaged from the carrier or fastener and an advanced position in which the carrier is advanced so as to bring a fastener into alignment with the end of the punch path. The movement of the engagement member back and forth between the retracted and advanced positions in response to the movement of the punch provides for reliable indexing of the fasteners in the carrier. It enables the carrier to be advanced along an arcuate feed path that has a sufficiently large radius to prevent kinking or unwanted bending of the carrier whilst allowing for a compact arrangement of the dispensing apparatus. In particular, a reciprocating engagement member can be arranged to occupy a much smaller spatial envelope in comparison to a rotating sprocket wheel. If the engagement member is arranged to engage the carrier rather than the fastener this has the advantage that it can be used with short fasteners that do not protrude significantly from the carrier. The idea of a reciprocating engagement member of this kind may be used independently of whether measures are taken to prevent lifting of the rivet or to support the punch during its passage through the body.
In operation the punch moves in a first direction along the punch path towards the workpiece. When it reaches the advanced position it extends into the fastener feed path so as to drive a fastener from the elongate carrier.
A nose may be provided for engagement with the workpiece. The nose may have a fastener delivery passage therethrough for delivery of a fastener to the workpiece after it has been removed from the elongate carrier and the fastener feed path by the punch. The fastener feed path may be defined at least in part by a clearance between the nose and the body. The nose is preferably fixed relative to the body. The nose may have an end surface for contact with the workpiece.
The actuator may be provided within the body so as to be engageable by the punch within the punch path, providing a compact solution to the problem of driving the feeding device.
The actuator may be engaged by a part of the punch in order to effect movement in the fastener feeding device. The engagement of the punch with the actuator may cause translational movement of the actuator substantially parallel to the punch path.
The actuator may be biased towards an initial position, to which it returns after engagement of the punch with the actuator ends. This return of the actuator means that the actuator need only be driven in one direction, which provides a simpler construction than one in which the actuator must be driven in both directions.
The bias may be provided by a resiliently compressible biasing member such as, for example, a spring. Translational movement of the actuator parallel to the punch path under engagement from the punch may cause compression of the biasing member.
The biasing member may be provided on substantially the opposite side of the punch path to the actuator.
Providing the biasing member separate from the actuator provides greater freedom in the design of the biasing member itself. It also allows a design of feeding mechanism in which the biasing member can be serviced and replaced without the need to remove or reposition the actuator, making the biasing member more easily accessible.
The punch may have a first portion at least a part of which extends from the punch path in the advanced position and a second portion, the actuator being moveable by the second portion of the punch. The actuator may be engageable by the second portion. The first portion may be a punch rod and the second portion may be a punch head or boss.
The actuator may be mechanically coupled to the at least one engagement member. The at least one engagement member may pivot about a pivot axis which intersects the body and/or which intersects the punch path. The at least one engagement member may have a first end that is coupled to the actuator and a second end for engagement with the carrier and/or the fastener. The pivot axis is preferably disposed between the first and second ends. The actuator may be biased by the biasing member, with the actuator being offset from the pivot axis on one side and the biasing member being offset from the pivot axis on an opposite side.
The body may have a bore that defines the punch path. The punch path or the bore may be defined by a support surface of the body and the punch may be supported along its length by the support surface as it reciprocates in the bore along the punch path. The support surface thus provides support to the punch throughout its insertion cycle such that in the event of a misfeed where the punch encounters a misaligned fastener and potentially damaging resistance forces are imparted to the punch the support surface prevents or restricts damage to the punch.
The punch path preferably defines a punch path axis along which the punch reciprocates and from which the punch extends to intersect the fastener feed path. The at least one engagement member is preferably moveable relative to punch axis.
The at least one engagement member may be external to the body or may be mounted within the body. The at least one engagement member comprises a first portion which extends alongside the body and a second portion which occupies the fastener feed path.
The at least one engagement member may engage the carrier or the fastener. In the case of the former the engagement member may comprise a main element and an engagement element moveable relative to the main element. The main element may be operated by the actuator and the engagement element may be moveably mounted on the main element. The engagement member may comprise a further biasing member, the further biasing member configured, in use, to bias the engagement element towards engagement with the carrier. The engagement element may be in the form of a tooth for engagement in an aperture or recess in the carrier.
The engagement element may be rotatably mounted on the main body. Such an arrangement is advantageous in that it allows more complex movement of the formation on the engagement member with respect to the carrier. The whole engagement member need not move in order to move the formation into (or out of) a driving position relative to the carrier.
The at least one engagement member may engage a fastener supported in the carrier. It may comprise an abutment surface such that, in use, the abutment surface abuts at least one of the fasteners supported in the elongate carrier so as to sequentially feed the fasteners into alignment with the end of the bore. The engagement member may have a tapered surface such that, in use, abutment of the tapered surface against at least one further fastener deflects the at least one engagement member around the fastener.
An advantage of engaging the carrier, rather than engaging a fastener in the carrier, is that the carrier can be reliably indexed through the apparatus even in the case when a fastener is missing from the carrier. Moreover, a wider variety of fasteners can be carried by the carrier since they do not need to be any particular shape in order to be indexed through the apparatus.
The body may comprise a guide bush for supporting the punch or it may be detachably connected to a guide bush that receives an upper part of the punch. The guide bush may be connectable to a driving actuator such as a hydraulic actuator.
A locking member may be provided that is engageable with the carrier such that, in use, the locking member prevents reverse movement of the carrier along the fastener feed path when a fastener is in the path of the punch. The locking member may be disposed in a downstream portion of the feed path.
The body may define an abutment surface in the fastener feed path, the abutment surface serving, in use, to prevent fasteners from being fed past the punch path and thus misaligned. The abutment surface may be an extension of the punch path.
The components of the fastener feeder device allow it to be packaged in a relatively slender unit in the direction of the tape. This allows the apparatus to be used in areas that have limited access. This is in contrast to existing insertion apparatus where the drive for the carrier tape is often disposed alongside the tape.
The fastener feed path may be defined by at least one carrier support for supporting the carrier in its movement along the feed path. A first carrier support may be defined on an opposite side of the fastener feed path to the body. The first carrier support may be defined upstream and/or downstream of the punch path. A second carrier support may be defined on the same side of the feed path and the punch path. At least part of the second carrier support may be defined by the fastener feed device and in particular by the at least one engagement member. At least part of the second carrier support may be defined upstream of the punch path. The at least one engagement member may be disposed so as to urge the elongate carrier into contact with the second carrier support. The second carrier support may define a recess to accommodate deflection of the carrier by the at least one engagement member.
According to a second aspect of the present invention there is provided fastener dispensing apparatus for dispensing fasteners into a workpiece, comprising: a body through which a punch path is defined; a punch at least partially within the punch path, the punch being reciprocally moveable between a retracted position and an advanced position in which the punch extends from an end of the punch path in order to drive a fastener towards a dispensing, the body defining a support surface that extends alongside the punch path and supports the punch during its movement along the punch path from the retracted to the advanced position; a fastener feed path extending transverse to the punch path, the fastener feed path being arranged for receipt of an elongate carrier of fasteners, the punch intersecting the fastener feed path in the advanced position; and a fastener feeding device for feeding the elongate carrier along the fastener feed path such that fasteners are sequentially brought into alignment with the end of the punch path, the fastener feeding device comprising an actuator moveable relative to the body by the reciprocal movement of the punch and at least one engagement member for engaging the elongate carrier or a fastener in the carrier, the at least one engagement member being moveable relative to the support surface.
The support surface may be defined by the part of the body that defines the punch path, which may be in the form of a bore. The body may also define a portion of the fastener feed path, more particularly an end of the body may define a surface that bounds the fastener feed path.
The apparatus in any of the aspects of the invention may be designed to insert a fastener into a workpiece after or at the same time as it is dispensed.
It will generally be appreciated that the features of the first aspect of the present invention as set out above may readily be taken in combination with the features of the second aspect of the present invention, either individually and in combinations.
According to a third aspect of the invention there is provided a method for dispensing a fastener comprising: providing an elongate carrier of fasteners in a fastener feed path; reciprocating a punch along a punch path in a body between a retracted position and an advanced position and into contact with a fastener disposed in the elongate carrier of fasteners, the fastener feed path extending transverse to the reciprocating direction of the punch, thereby driving a fastener out of the carrier towards a dispensed position; and using an actuator to feed the elongate carrier along the fastener feed path such that fasteners are sequentially brought into alignment with the end of the punch path; the reciprocal movement of the punch effecting movement of the actuator relative to the body; engaging the elongate carrier or at least one fastener in the elongate carrier with at least one engagement member and moving the at least one engagement member relative to the body in response to movement of the actuator; supporting a fastener adjacent to the punch path with a surface of the body, the surface defining at least part of the fastener feed path.
According to a fourth aspect of the present invention there is provided a method for dispensing a fastener comprising: providing an elongate carrier of fasteners in a fastener feed; reciprocating a punch along a punch path in a body between a retracted position and an advanced position and into contact with a fastener disposed in the elongate carrier of fasteners, the fastener feed path extending transverse to the reciprocating direction of the punch, thereby driving a fastener out of the carrier towards a dispensed position; supporting the punch with a support surface that extends alongside the punch path and supports the punch during its movement along the punch path from the retracted to the advanced position; using an actuator to feed the elongate carrier along the fastener feed path such that fasteners are sequentially brought into alignment with the end of the punch path; the reciprocal movement of the punch effecting movement of the actuator relative to the body; engaging the elongate carrier or at least one fastener in the elongate carrier with at least one engagement member and moving the at least one engagement member relative to the body in response to movement of the actuator.
In each of the method aspect of the invention the fastener may be inserted into a workpiece after or at the same time as being dispensed.
It will be appreciated that the inventive aspects outlined above may be applied to the dispensing, placing or insertion of components other than fasteners using the same feeding device.
Specific embodiments of the invention are now described, by way of example only, with reference to the accompanying figures, in which:
Referring now to
A generally frustoconical nose 7 is provided beneath the lower end of the guide bush 2, the nose 7 being spaced from the guide bush 2 so as to provide a clearance between the nose 7 and the guide bush 2 for the feed path P. The nose 7 defines a longitudinal passage 8 in axial alignment with the bore 3 of the guide bush 2. At the lower end of the passage 8, the nose 7 defines a generally annular face 9 for contacting a workpiece (not shown) to be fastened.
In use, a tape 10 defining holes 10A for carrying rivets 11 is fed laterally along the path P beneath the guide bush 2 between the walls 5A by a fastener feeding mechanism that ensures that each rivet 11 in turn is axially aligned with the bore 3 and thereby the path of the punch 6 as will be described in more detail below.
The structure of the fastener insertion apparatus 1 is now described in greater detail. The bore 3 is divided into a wide diameter section 12 adjacent to the upper opening 4 and a narrow diameter section 13 adjacent to the lower opening 5. The guide bush 2 thus defines an internal annular shoulder 14 at the junction between the wide and narrow sections 12, 13 of the bore 3.
A cavity 15 running substantially parallel to the bore 3, extends between the lower end of the guide bush 2 and the wide diameter section 12 of the bore 3, merging at its upper end with the wide diameter section 12 at an internal aperture 16 which is partially defined by a portion of the shoulder 14 and partially defined by a portion of the wall of the wide section 12. The cavity 15 is sufficiently radially offset from the bore 3 that the wall of the wide diameter section 12 defines an abutment surface 17 within the cavity 15 adjacent to the internal aperture 16. A cylindrical actuator 18 is slidably disposed within the cavity 15. An end cap 19 (held by a pin 19A depicted in
Two elongate slots 21 in the guide bush 2 extend along a portion of the length of the cavity 15, exposing the cavity 15 to the exterior of the guide bush 2. A hole 22 extends laterally through the actuator 18 so as to receive an actuating pin 23, the ends of which extend through the slots 21 to the exterior of the guide bush 2. Therefore, as the actuator 18 reciprocates within the cavity 15, the ends of the actuating pin 23 slide in the slots 21. Each end of the actuating pin 23 is mechanically engaged with a respective catcher 24 mounted on the exterior of the guide bush 2. The catchers 24, described in detail below, engage the rivets 10 so as to feed them into the path of the punch 8. The catchers 24 themselves are prevented from passing into the path of the punch by a guard pin 24A which projects from either side of the guide bush 2 adjacent to the lower end of the bore 3.
The two catchers 24 are in the form of generally longitudinally extending arms with laterally extending tips 25. The catchers 24 are mounted via pivot pins 26 on radially opposite sides of the exterior surface of the guide bush 2 such that the axis of rotation of the catchers 24 intersects the principal axis of the bore 3. The end of each catcher 24 remote from the laterally extending tips 25 is located adjacent to one of the elongate slots 21 and defines a slot 27 for mechanical engagement with an end of the actuating pin 23 protruding from the elongate slot 21. At the opposite end of each catcher 24, the laterally extending tip 25 extends across the lower end of the guide bush 2 such that the laterally extending tips 25 of the two catchers 24 meet one another in the path P between the guide bush 2 and the nose 7. The guard pin 24A extends through the guide bush 2 adjacent to the lower end such that its opposite ends protrude from the radial exterior surface of the guide bush 2. The catchers 24 rest against these opposite ends of the guard pin 24A so as to prevent the laterally extending tips 25 from moving into the path of the punch 6.
The fastener feeding mechanism thus comprises the actuator 18, spring 20, the actuating pins 23, the catchers 24 and the pivot pins 26. The actuator reciprocates within the cavity 15, carrying the actuating pin 23, which forces the catchers 24 to pivot about the pivot pins 26 such that the laterally extending tips 25 first sweep (in a first direction) away from the guard pin 24A before returning back (in an opposite second direction) to their original position against the guard pin 24A.
Each laterally extending tip 25 has a leading edge 28, which leads when the laterally extending tips 25 move in the first direction, and an opposite trailing edge 29. The leading edge 28 tapers so as to present an oblique angle to the first direction of movement of the tips 25. The catchers 24 are sufficiently flexible and resilient that they deflect outwardly from one another under stress so as to create a gap between the tips 25. When not under stress, the catchers 24 resiliently return to their original shape and the tips 25 once again meet between the guide bush 2 and the nose 7. It will be appreciated therefore that if the tapered leading edges 28 of the tips 25 abut an obstacle during movement in the first direction, the tips 25 (and thereby the catchers 24) will be deflected outwardly so as to pass the obstacle. However, if the trailing edges 29 of the tips 25 abut an obstacle during movement in the second direction, the lack of a taper on these edges 29 means that no such deflection will occur.
The holes 10A in the carrier tape 10 are evenly spaced along its length. Each rivet 11 comprises a shank 30, which is slightly larger than the holes 10A in the tape 10 so that the shank is a friction fit with the tape, and a head 31, which has greater cross-sectional dimensions than the holes 10A. Thus, each rivet 11 sits in the tape 10 such that the shank 30 passes through a hole 10A in the tape and the rivet head 31 abuts the tape to prevent the rivet 11 falling out of the tape 10.
In use, as shown in
The punch 6 comprises a piston head 32, which is drivable through the upper opening 4 of the guide bush 2 by an appropriate driving actuator, and punch rod 33, which extends from the piston head 32. The arrangement is such that during reciprocation of the punch (in a rivet insertion cycle) the lower end of the punch rod 33 emerges from the lower opening 5 in the guide bush 2 so as to engage a rivet 11 and insert it into a workpiece. The diameter of the piston head 32 corresponds closely to that of the wide section 12 of the bore 3 and the diameter of the punch rod 33 corresponds closely to that of the narrow section 13. Accordingly, the piston head 32 is guided and supported by the wide section 12 of the guide bush 2, and while the punch rod 33 is travelling within the narrow section 13, it is also guided and supported by the guide bush 2. The extent of possible translation of the punch 6 within the bore 3 is restricted in that the piston head 32 cannot move into the narrow section 13 of the bore 3. It will be apparent that as the punch 6 is advanced within the bore 3, the piston head 32 abuts the actuator 18 forcing it to slide against the spring 20 further into the cavity 15.
In operation, as shown in
The feeding mechanism is advantageous in that the reciprocation of the punch 6 during each rivet insertion cycle causes the next rivet 11 to be fed into the path of the punch 6. This is a simple and elegant solution to the problems of powering and timing the feeding of the rivets 11 into the path of the punch 6. The catchers 24, actuator 18, guard pin 24A and tape 10 are configured such that when the catchers sweep back to their original position the next rivet 11B is correctly aligned with the path of the punch 6. It will, however, be appreciated that in the event that the relationship between these components is altered, for example if there is a defect in the tape 10, the abutment surface 5B prevents overfeeding of the rivet 11B past the bore 3, maintaining the rivet 11B in the path of the punch 6.
The provision of catchers 24 that move around the guide bush 2 ensures that the punch 6 can be supported during its advance. In particular, the guide bush 2 provides a bore 3 that extends close to the point at which rivets 11 are driven out of the tape 10. This is advantageous in that the punch 6 is less likely to be damaged in use if it is supported as it extends. Furthermore, rivets 11 which are being fed into the path of the punch 6 are close to the lower end of the guide bush 2, which more tightly controls the movement of the rivets 11 than if the tape 10 was moving through an open space.
Two examples illustrating the advantages of this embodiment of the present invention are described below with reference to
In operation, two malfunctions that can occur in rivet insertion apparatus are partial feeding, in which a rivet is not fully aligned with the path of the punch, and rivet “lifting”, in which the return motion of the punch causes the punch to “lift” the next rivet dislodging it from its seated position in the tape.
Further embodiments of fastener insertion apparatus which engage with the tape rather than the rivets so as to move the tape through the apparatus are now described with reference to
The fastener insertion apparatus 101 comprises a longitudinal guide bush 102A, beneath which is provided a fastener feed assembly 102B comprising a body B that supports a number of feed assembly components. The nose 107 is mounted beneath the fastener feed assembly 102B and defines a passage 108 (see
In use, a carrier tape 110 of rivets 111 (other fasteners may be used) is fed along the feed path P. Two substantially vertical tubes 137 (shown only in
Whereas in the first embodiment of the invention the fastener feed mechanism 18, 20, 23, 24, 26 is arranged in and around the guide bush 2, in this second embodiment there is provided a separate feed assembly 102B that is disposed below the guide bush 102A. An advantage of providing the guide bush and feed assembly as separable components is that servicing and maintenance of the feed assembly may be performed more easily. Moreover, different size feed assemblies may be connected to the guide bush 102A. It will be appreciated that in many respects the fastener feed assembly 102B functions in the same way as the fastener feed mechanism of the first embodiment.
In particular, it will be appreciated that both the guide bush 102A and the feed assembly 102B support and guide the punch 106 as it reciprocates during rivet insertion. The punch 106 reciprocates within a bore 103 defined partly by the guide bush 102A and partly by the feed assembly 102B. The guide bush 102A defines a wide section (not shown) of the bore 103 and the fastener feed assembly 102B defines a narrower section of the bore, analogous to the upper and lower sections 12, 13 of the bore 3 of the first embodiment. The guide bush 102A is only shown in
Referring to
The fastener feed assembly body B houses a feed mechanism which is engaged by the punch 106 so as to feed rivets 111 into the path P. The body B has a cylindrical upper end defining an annular upper surface 114, having at its centre the upper opening of the narrow section 113 of the bore 103. At the exterior edge of the annular surface 114, a circumferential exterior rim 139 is defined for engagement with the guide bush 102A. A pair of screws 140 which project upwardly out of opposite sides of the annular surface 114 are used to secure the guide bush 102A to the feed assembly 102B.
A pair of indexing arms 141 is rotatably mounted to the body B on pivot pins 126 that are received in respective apertures 142 defined in the arms 141. The indexing arms 141 are mounted in a similar way to the catchers 24 of the first embodiment and move in a similar way, so as to perform a similar function. In contrast with the catchers 24, however, the indexing arms 141 are mounted inside the body B of the feeder assembly 102B. Each indexing arm 141 comprises a curved edge 141A which, in use, is adjacent to an upper edge of the tape 110. Each curved edge 141A defines a single tooth 143 having an oblique upstream edge (with respect to the feed path P) and an upright downstream edge. Each tooth 143 is configured to engage a corresponding series of regularly spaced indexing holes 144 defined towards the edge of the tape 110. When one of the teeth 143 is in an indexing hole 144, the upright edge of the tooth 143 is engageable with the edge of the indexing hole 144 such that rotation of the indexing arm 141 so as to move the tooth 143 in a downstream direction drives the tape 110 downstream with the tooth 143. When the indexing arms 141 rotate so as to move the teeth 143 in an upstream direction, however, the oblique upstream edge of the tooth 143 bears against the edge of the indexing hole 144 and lifts the tooth 143 out of the hole 144, allowing the tooth 143 to slide along an upper surface of the tape 110 to the next hole 144. Subsequent downstream movement of the tooth 143 (as described above) then causes the tooth 143 to engage with the edge of this next hole 144 and drive the tape 110 in the downstream direction. In this way the indexing arms 141 may be rotated back and forth so as to reliably index the tape 110 through the apparatus 101. The mechanism by which the indexing arms 141 are actuated is now described.
A pair of elongate actuators 145 are slidably mounted side by side above the fastener feed path P. The actuators 145 are connected together at their lower ends by a transverse first load spreading bar 146. In a retracted position the upper ends of the actuators 145 extend above the annular surface 114 towards the piston head 132. The first load spreading bar 146 abuts downstream portions of the indexing arms 141 such that, when the actuators 145 are pushed downwards to an extended position, the first load spreading bar 146 forces the indexing arms 141 to rotate about pins 126 such that the teeth 143 move in an upstream direction. A pair of compression springs 147 is provided within a cavity 148 on the upstream side of the feed assembly 102B. The compression springs 147 are retained within the cavity 148 by a spring retainer 147A fixed in the upper surface of the fastener feed assembly 102B. The compression springs 147 are joined together at their lower ends by a second load spreading bar 149 parallel to the first load spreading bar 147, and which engages upstream portions of the indexing arms 141 when the arms 141 rotate in an upstream direction. Thus, downward movement of the actuators 145 rotates the indexing arms 141 so as to compress the compression springs 147 between the indexing arms 141 and the end cap 147A. When the indexing arms 141 are no longer being held against the resilience of the compression springs 147, the springs 147 bias the indexing arms 141 back towards their initial position so that the actuators 145 are pushed back up to their retracted position. The end cap 147A serves for easy access to the compression springs 147 for servicing and replacement. The actuators 145 are extended and retracted as the punch descends and retracts during a rivet insertion cycle, and this rotates the indexing arms 141 as described above, thus indexing the tape 110 through the apparatus 101. Adjacent to the actuators 145 on the downstream side of the guide bush 102, a static stop member 150 is provided in the rotational path of the indexing arms 141 so as to prevent over-rotation of the indexing arms 141 past their initial position upon their return (forward) movement.
So as to improve the reliability with which the punch 106 drives rivets 111 from the tape 110, rotatable tape retainers 151 flank the arms 141 and are supported on the same pivot pins 126 so as to rotate with the indexing arms 141. The tape retainers 151 have substantially the same profile as the indexing arms 141, having edges adjacent the edges 141A which run along edge portions of the upper surface of the tape 110, but do not define teeth for engagement with the tape 110. A pair of walls 156 flank the rivet path P on each side and are disposed below the retainers 151 with a small clearance for receipt of the carrier tape 110. The upper surface of the walls 156 serve to guide the underside of the tape along the path P whilst the tape retainers hold the tape against walls 156. A lower portion of each wall has a shoulder 153 that serves to support the tape under the retainers 151 and on the downstream side, the tape having ridges 154 at its edges which run against a top edge of the wall 156 so as to maintain the tape in alignment in the fastener feed path P.
On the upstream side in order to ensure that the tape 110 is fed into the apparatus 101 at an appropriate angle, the upper surface of the walls 156 are inclined at an appropriate angle. The upper surfaces of the walls 156 each define a recess 156A (best seen in
It will be appreciated that several modifications may be made to the walls 156 so as to improve the reliability of support and/or ease of construction, including the addition of a biasing member (e.g. a resilient pad) within the recess 156A, which biases the tape 110 towards the indexing arm 141. Alternatively, the recess 156A may be omitted and the upstream portion of the wall 156 configured to be moveable relative to the body B in a lateral direction away from the punch axis, such that force applied by the indexing arms 141 and tooth 143 on the carrier tape 110 moves the wall 156 in the lateral direction.
As shown in
So as to improve the reliability of insertion of rivets 111 by the apparatus 101, the nose 107 is provided with a plurality of bearings 157 which defined the passage 108. The bearings 157 are biased inwardly by one or more elastomeric members 158 such that a rivet 111 passing through the passage 108 is prevented from tumbling and is thus correctly inserted into the workpiece.
In operation, the fastener insertion apparatus 101 of the second embodiment functions according to the following sequence. A carrier tape 110 of rivets 111 is loaded such that a first rivet 111 is in position in the path of the punch 106 under the bore 103. A workpiece is positioned over the die 136 in the path of the punch 106 and the nose 107 brought into contact with the workpiece so as to retain it in place and optionally apply a desired clamping force at any stage before, during or after rivet insertion. The punch 106 translates axially downwards and the punch rod 133 strikes the rivet 111A, driving it out of the tape 110, down the passage 108 and into the workpiece. The punch rod 133 occupying the hole 110A in the tape 110 prevents further movement of the tape until the punch 106 retracts and is withdrawn from the tape 110 later in the cycle.
During descent of the punch rod 133 to drive the rivet 111A from the tape 110, the piston head 132 strikes the actuators 145, pushing the actuators 145 downwardly. The actuators 145 push the indexing arms 141, causing them to rotate and move the teeth 143 in an upstream direction, thereby compressing the compression springs 147 as described above. The teeth 143 leave the indexing holes 144 and proceed upstream beyond the next set of holes 144. At this point, the apparatus 101 is as shown in
In a third embodiment, shown in
A fourth embodiment of a fastener insertion apparatus 301 in accordance with the present invention is shown in
It will be appreciated that the indexing arm 341 could take any suitable form. In one alternative embodiment it may take the form of a flat torsional spring with an integral tooth.
A further difference in the fourth embodiment is that the elongate tape guide 352 is provided with a rotatably mounted locking member 363 downstream of the path of the punch 306, beneath the tape 310 and aligned with the indexing holes 344 in one side of the tape 310. The locking member 363 is biased upwardly against the tape by a compression spring 364A mounted on a support 365 projecting from the nose 307. The spring is covered by a cap 364 that bears against the locking member 363. The locking member 363 defines a tooth 366 on its upper edge for engagement with tape indexing holes 244. The tooth 366 has an oblique edge on its upstream side and an upstanding edge on its downstream side, such that movement of the tape 310 in the downstream direction pushes the locking member 363 downwards, compressing the spring 364A. Thus, the indexing holes 344 in the tape 310 index past the locking member 363 as the tape 310 moves downstream. The holes 344 in the tape 310 and the position of the locking member 363 are such that, when a rivet 311 in the tape 310 is in the path of the punch 106, the tooth 366 of the locking member 363 sits in an indexing hole 344 in the tape 310 and prevents reverse, upstream, movement of the tape 310 by engagement between the upstanding edge of the tooth 366 and the edge of the hole 344. This is advantageous in that during a punching action, even when the punch rod 333 is not pinning the tape 310 in position, the tape 310 cannot be pulled backwards through the apparatus 301 (for example, by the upstream movement of the indexing arm 341). It will be appreciated that the feature of a locking member 363 may advantageously be added to any of the other embodiments.
The embodiments of
The indexing is performed by an indexing mechanism that disengages and re-engages with the tape or the fasteners as compared to conventional sprocket drives in which the drive is permanently engaged.
It will be appreciated that numerous modifications to the described embodiment may be made without departing from the scope of the invention as defined by the appended claims. In particular, it will be apparent that the fastener feed assembly or mechanism comprising a spring biased actuator and a pair of catchers or indexing arms may be replaced by any desirable mechanism provided that actuation occurs as a result of the movement of the punch relative to the guide bush and/or feed assembly. The actuator is provided within the guide bush or feed assembly so as to allow the guide bush or feed assembly to guide and support more of the range of movement of the punch. It will be appreciated that many of the features described in relation to different embodiments might be incorporated, individually or in combination, into a single embodiment of a fastener insertion apparatus in accordance with the present invention.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the scope of the inventions as defined in the claims are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least
This application is a national phase application of PCT Application No. PCT/GB2010/001957, filed Oct. 22, 2010 which claims priority to U.S. Patent Application No. 61/260,151, filed Nov. 11, 2009, the entire contents of which are hereby incorporated by reference therein.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB10/01957 | 10/22/2010 | WO | 00 | 5/9/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 61260151 | Nov 2009 | US |
