GB2151176A - Fastener feeding arrangements and driving apparatus - Google Patents

Abstract

A fastener feeding arrangement characterised by: a fastener delivery track (19) for guiding and delivering in sequence fasteners (26) secured together in series; an access member (22; 66) movable between a first position in which it covers at least a part of said track and a second position in which at least said part is exposed; a feeding member (36) mounted for reciprocating motion and being adapted to engage at least one fastener to advance the series of fasteners along said track; drive means (32 to 35) for enabling reciprocating motion of said feeding member (36); and disabling means (49 to 55) responsive to the position of said access member to disable said drive means when said access member is in said second position. <IMAGE>

Description

SPECIFICATION Fastener Feeding Arrangements and Driving Apparatus This invention relates to fastener feeding arrangements and to fastener driving apparatus.

Pneumatically actuated fastener driving apparatus is in widespread use and has many advantages both from a labour and time-saving standpoint. It is known to those skilled in the art that fasteners, such as nails, can be interconnected in series by flexible and breakable material bonded to the shank portion of each fastener. Such material could be wires welded to shanks of nails. The series of fasteners can then if desired be made into a compact package by forming them into a coil.

A cylindrical magazine is normally attached to fastener driving apparatus for containing such a compact coil of fasteners. The portion of the driving apparatus between the magazine and the fastener driving throat, known as a delivery track, is used to house a fastener guidance and feeding arrangement. A feed member for delivery of the fasteners from the magazine into the throat from which they are to be driven with a single stroke of the apparatus is also mounted on the delivery track.

Fastener driving apparatus usually has a section of the fastener delivery track that can be opened for clearing a jam as well as for ease in reloading. Also in known fastener driving apparatus the feed member is biased forward toward the fastener driving throat by a compression spring, or a pneumatic-type piston.

During or between each driving stroke, the feed member is retracted to engage the shank portion of a fastener in the lead portion of the coil, so that when the driver returns to its upmost position, the leading fastener of the coil is delivered into the driving throat of the apparatus. These systems work well for reloading a coil of fasteners but give considerable problems if it becomes necessary to remove the leading portion of a coil from the driving throat and delivery track.

To remove the fasteners, the spring force must be deactivated or overcome manually. In the case of a pneumatic type piston, the air connection to the apparatus can be removed and the reservoir within the apparatus discharged. These and other methods of deactivating the forward thrust on the feeding device are both time-consuming and unsafe.

An object of this invention is to provide a fastener feeding arrangement which simplifies the process of removing fasteners from the delivery track and renders the procedure more safe.

Another object of this invention is to provide a fastener feeding arrangement in which a feed member has freedom of movement in either forward or reverse direction when a part of the delivery track is exposed for ease of access.

According to one aspect of the invention, there is provided a fastener feeding arrangement characterised by a fastener delivery track for guiding and delivering in sequence fasteners secured together in series; an access member movable between a first position in which it covers at least a part of said track and a second position in which at least said part is exposed; a feeding member mounted for reciprocating motion and being adapted to engage at least one fastener to advance the series of fasteners along said track; drive means for enabling reciprocating motion of said feeding member; and disabling means responsive to the position of said access member to disable said drive means when said access member is in said second position.

According to a further aspect of the invention there is provided fastener driving apparatus including said arrangement of said one aspect.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows a side view of fastener driving apparatus; Figure 2 is a partial end elevation of the apparatus of Figure 1; Figure 3 is a cross-section of part of a delivery track of the apparatus along the center line thereof; Figure 4 is a cross-section of a fastener feeding arrangement, with a track door closed, along line A-A of Figure 1; Figure 5 is the same as Figure 4 with the feeding device in a backward position; Figure 6 is a schematic cross-section along line B-B of Figure 4 with track door open; Figure 7 is the same as Figure 6 with track door closed; Figure 8 is the same view as Figures 6 and 7 with a modified air passage;; Figure 9 is the same as Figure 8 with the passage exhausted to atmosphere; Figure 10 is the same view as Figures 6 to 9 with a spring actuated piston; and Figure 11 is the same as Figure 10 with the track door closed.

Referring first to Figure 1, a feeding device 15 is mounted on a fastener driving apparatus 16 having a body 18 to which a magazine 17 is attached. A delivery track 19 is mounted on the body 18 in alignment with the magazine 17 such as to allow movement of the fasteners 26 from the magazine 17 into a fastener driving throat 20.

As shown in Figure 3, disposed within the body 18 is a fastener driver 21 slidable in the driving throat 20. Attached to the driver is a piston slidably disposed within a cylinder in the body 18. Avalve means for reciprocating movement of the piston and driver is also disposed within the body 18. The driver, piston, valve means, etc. are wholly conventional and may vary depending on the size and style of fastener driving apparatus 16.

Referring now to Figure 2, a movable track door 22 is mounted on the delivery track 19 by suitable means such as pin 23. The door 22 is normally secured closed by latch 24 when the tool is in operation. By manually releasing the latch 24, the door 22 can be pivoted open exposing a fastener guideway 25 (Figure 3) for easy access to clear jams or to load a new coil of fasteners 26.

On each successive cycle of the tool, the driver 21 moves downwardly within the driving throat 20 and contacts the striker end 26a of the fastener 26. The downward force fractures a breakable bond between a wire 27 and the fastener in the driving throat 20. The striker ends of the fasteners within the delivery track 19 are supported in a slot 28so that they cannot move longitudinally of the fasteners.

The driver 21 of course moves the fasteners seqentially from the driving throat 20 and into a workpiece.

During the stroke of the driver 21, compressed air is delivered to the feeding device 15 to activate the device for feeding the next fastener into position to be driven on the next cycle of the tool. This feed mechanism is described in more detail in Figures 4 and 5.

The delivery track 19 houses a first cylinder 29 open on one end and closed on the opposite end by seal 30 and retaining clip 31. Slidably disposed within cylinder 29 is a piston 32 and a rod 33. A second cylinder 34 on the same axis as first cylinder is also housed in the delivery track 19. Slidably disposed within cylinder 33 is further piston 35 attached to a rod 33. Although the piston 35 is shown as a continuation of piston 32 and rod 33, the members could be separate elements suitably attached to operate as a single unit. The cylinder 34 and piston 35 operate essentially as a air spring.

Intermediate the pistons is a fastener feed pawl 36 having a toothed portion 38 and pivotally mounted on the rod 33. The pawl 36 is biased toward the fasteners 26 by a spring 37. As the rod 33 moves to the left to the position shown in Figure 5, the pawl 36 is moved away from the driving throat 20. As the toothed portion 38 of pawl 36 contacts each fastener 26, it pivots clockwise until the end of the toothed portion 38 clears the fastener 26. The spring 37 will force the pawl 36 to pivot counterclockwise again and the toothed portion 38 will rest behind the next fastener. When the rod 33 and consequently the pawl 26 moves to the right, the toothed portion engages a fastener so that the fasteners are pulled along the delivery track 19 toward the driving throat 20.

A retention pin 39 mounted in the track door 22 prevents the fasteners from moving backwards as the feed pawl 36 moves to the left. An end portion of the retention pin 39 extends into the path of the fasteners. The shape of the extension allows the fastener to force the retention pin 39 out of the path during forward movement of the fasteners yet will not move when a force is exerted backward. A spring 40 biases the retention pin 39 toward the fasteners and a clip 41 retains the pin 39 disposed in the track door 22.

Figures 6 and 7 are cross-sectional views perpendicular to the plane of Figures 4 and 5 to show air passage for functional operation, but do not necessarily represent the actual orientation of the elements shown.

Passage 42 is in continuous communication with pressurized air in a reservoir in the body 18. Passage 43 in the delivery track 19 is a continuation of the passage 42 and is isolated from atmosphere by a seal 44. Passage 45 is pressurized momentarily and then exhausted to atmosphere during the driving cycle of the tool. Passage 46 in the delivery track 19 is a continuation of the passage 45 and is isolated from the atmosphere by a seal 47.

Within the delivery track 19 is a first bore 48 and a second bore 49 having the same axis. Slidably disposed within the bores is a valve stem 50 having a first diameter and a seal 51 sized to correspond to the first bore 48 and a second diameter with a seal 52 sized to correspond to the second bore 49.

Passage 43 intersects bore 48 so that bore 48 is pressurized when the tool is connected to a pressurized air supply.

Since the valve stem 50 has portions of differing area, there is a force imbalance holding the valve stem 50 to the left as shown in Figure 6. The stem 50 is retained within the drive track 19 by a clip 53 attached to one end. The opposite end protrudes from the drive track.

Passage 54 intersects bore 49 and cylinder 34 through port 55 in the cylinder wall. An undercut in the smaller diameter of the valve stem 50 allows cylinder 34to be in communication with atmosphere. Cylinder 29, passage 46 and passage 45 are in communication with atmosphere when the tool is at rest, therefore, the rod 33 with feed pawl 36 attached is free to move longitudinally. Fasteners can be easily removed from the driving throat 20 and delivery track 19.

When the movable track door 22 is closed and secured in operative position, the valve stem 50 is forced to the right as shown in Figure 7.

Seal 52 is now on the other side of passage 54, allowing cylinder 34 to be in communication with pressurized air from the reservoir in the body 18 through passages 42,43,48, 54 and 55. Piston 35 and rod 33 are now under a force to the right as viewed in Figure 7. The cylinder 34 and piston 35 function as a constant force air spring acting upon rod 33.

During the downward stroke of the driver 21, cylinder 29 is momentarily pressurized by a means wholly conventional to the particular tool upon which feeding device is mounted. Piston 32 having a larger area than piston 35 creates a differential force on the rod 33 thereby moving rod 33 and pawl 36 attached thereto to the left as viewed in Figure 5.

When the cylinder 29 is again in communication with atmosphere, the force on piston 35 will move the rod 33 back to the right. This motion of the rod 33 and pawl 36 attached thereto feeds the fasteners toward the driving throat 20 as previously described.

Figures 8 and 9 show a modified passageway allowing cylinder 34 to be pressurized when track door 22 is closed and secured in an operative position.

Passage 42 is in continuous communication with pressurized air in the reservoir in the body 18 when the tool is connected to a pressurized air supply.

Passage 56 in the delivery track 19 is in communication with passage 42 isolated from atmosphere by seal 44. Passage 57 is a continuation of passage 56 although having a larger crosssectional area. Passage 57 communicates with bore 49 and cylinder 34 through port 55 in the cylinder wall. Passage 58 allows communication between passage 57 and atmosphere.

Although pressurized airflowsthrough passage 56, the volume is small compared to the volume that can exhaust to atmosphere through passage 58. The pressure in cylinder 34 is negligible as long as passage 58 is exhausting to atmosphere. Therefore rod 33 can be moved freely longitudinally.

When track door 22 is closed and secured, a seal 59 on the door breaks communication between passage 58 and atmosphere thereby pressurizing passages 42, 56, 57, 58, port 55 and cylinder 34.

Cylinder 34 and piston 35 then function as a constant force air spring acting upon rod 33. The action of the device to feed fasteners is the same as previously described.

The passage 58 could be located directly in the end portion of cylinder 34 instead of intersecting passage 57. Passage 56 being of smaller size could then connect to port 55. The operation would be exactly the same since the volume that could flow out of passage 58 would again be much greater than that entering port 55 through passage 56. The resulting pressure in cylinder 34 would be negligible and the rod 33 could be moved freely longitudinally.

Referring now to Figure 10, the cross-sectional view shows an embodiment in which a spring force biases the feeding member foward but does not necessarily represent the actual orientation of the elements shown.

Within the delivery track 60 is a cylinder 29, piston 32, rod 33, passage 45 and passage 46. The function of these elements is the same as previously described and shown in Figures 6 to 9.

The delivery track 60 has a counterbore 61 having one open end. Slidably disposed within a counterbore 61 is a rod 62 which in turn could be a continuation of rod 33. A slot 63 within the delivery track 60 intersects the counterbore 61 along its axis.

The slot 63 has a width less than the diameter of the counterbore 61. A spring 64 disposed within the counterbore 61 is contained by the rod 62 and the bottom 65 of the counterbore 61.

The rod 62 has a limited longitudinal movement such that one end of the rod 62 remains within the counterbore 61. The length of the spring 64 in relation to the depth of the counterbore 61 will allow the rod 62 to move freely longitudinally so as to be able to remove fasteners from the delivery track as previously described.

Figure 11 shows a movable track door 66 secured closed, an end portion being disposed in slot 63 to force the.spring 64 along the counterbore 61 to create a biasing action on the rod 62 toward the fastener driver. During the downward stroke of the driver, cylinder 29 is momentarily pressurized. The pressurized force is greater than that of the spring 64 so that the rod 33, rod 62 and pawl 36 move to the left as shown in Figure 11.

When the cylinder 29 is again in communication with atmosphere, the spring force will move the rod 62 back to the right. This motion feeds fasteners forward as previously described.

The preserit invention thus provides a new and improved fastener feeding device allowing easy and safe removal of fasteners.

Claims (15)

1. A fastener feeding arrangement characterised by: a fastener delivery track (19) for guiding and delivering in sequence fasteners (26) secured together in series; an access member (22; 66) movable between a first position in which it covers at least a part of said track and a second position in which at least said part is exposed; a feeding member (36) mounted for reciprocating motion and being adapted to engage at least one fastener to advance the series of fasteners along said track; drive means (32 to 35) for enabling reciprocating motion of said feeding member (36); and disabling means (49 to 55) responsive to the position of said access member to disable said drive means when said access member is in said second position.

2. An arrangement according to claim 1 characterised in that said drive means comprises a piston rod (33) on which said feeding member is mounted.

3. An arrangement according to claim 2 characterised in that biasing means (34,35; 64) is provided to bias said piston rod in one direction and in that said disabling means is arranged to disable said biasing means.

4. An arrangement according to claim 3 characterised in that said biasing means is an air spring and said disabling means is arranged to de-pressurize said air spring.

5. An arrangement according to claim 4 characterised in that ducting means are provided to supply compressed air to said air spring and in that relief means are provided as said disabling means in order to open said ducting means to ambient pressure in response to movement of said access member to said second position.

6. An arrangement according to claim 5 characterised in that said ducting means including a switch member biased to a position in which it opens said ducting means to ambient pressure and in that said access member is arranged to hold said switch member against said bias when in said first position.

7. An arrangement according to claim 5 characterised in that said relief means comprises an air outlet (58) and in that sealing means (59) is provided on said access member to seal said outlet when in said first position.

8. An arrangement according to claim 3 characterised in that said biasing means is a coil spring (64) and said disabling means comprise a movable back stop for said coil spring.

9. An arrangement according to claim 8 characterised In that said back stop is provided on said access member.

10. An arrangement according to any one of claims 2 to 9 characterised in that said drive means includes means for supply of compressed air to one end of said piston to cause said movement.

11. Fastener driving apparatus characterised by a fastener feeding arrangement according to any one of the preceding claims.

12. Apparatus according to claim 11 and having a fastener driving member, characterised by means for synchronising operation of said feeding arrangement with operation of the driving member.

13. Apparatus according to claim 11 or 12 characterised in that it is operable pneumatically.

14. A fastener feeding arrangement substantially as hereinbefore described with reference to the accompanying drawings.

15. Fastener driving apparatus substantially as hereinbefore described with reference to the accompanying drawings.