COLLINSON, David (30 Mundy Street, Mentone, Victoria 3194, 3194, AU)
ALIREZAEE, Tayebeh (3/67 Carroll Crescent, Glen Iris, Victoria 3146, 3146, AU)
COLLINSON, David (30 Mundy Street, Mentone, Victoria 3194, 3194, AU)
| CLAIMS: 1. A fastener driving tool assembly for operation by an operator in a standing position, the assembly comprising upper and lower tubes telescopically mounted, a drive shaft extending through the tubes from a drive tool at the upper end of the upper tube, the drive shaft having a driving bit at its lower end, a housing at the lower end of the lower tube and having a chamber to receive a fastener to be driven into sheeting on which the operator is standing, the drive tool and upper tube being displaceable downwardly relative to the lower tube by the operator to place the driving bit in driving engagement with the head of the fastener, and a fastener feed system comprising a feed tube for storing individual fasteners in end to end relation along the tube, the lower end of the feed tube communicating with the chamber in the housing, and a control mechanism for releasably retaining the lowermost fastener in the feed tube and for releasing that fastener for passage into the chamber, operation of the control mechanism being responsive to movement of the upper tube to lower or raise the driving bit within the chamber, the control mechanism comprising a control cam slidably mounted on the feed tube and displaced by movement of the upper tube within the operational cycle of the assembly. 2. An assembly according to claim 1 , wherein the control mechanism comprises upper and lower fingers movable into the feed tube to an extent sufficient to engage the lowermost fastener within the tube and the next adjacent fastener and retractable to an extent sufficient to release the fasteners, the fingers being operable alternately by the control cam such that when the lower finger has been retracted to release the lowermost fastener for passage into the housing, the upper finger can engage the next adjacent fastener to retain that fastener and thereby the fasteners above that fastener, and when the upper finger is withdrawn to release that fastener the lower finger will act to releasably retain that fastener for the next cycle of operation. 3. An assembly according to claim 2, wherein the upper and lower fingers are carried by a rocker arm which is spring biased to pivot the arm into a position in which the lower finger is in its retaining position and the upper finger in its released position, and movement of the cam along the feed tube by movement of the upper tube downwardly causes pivotal movement of the rocker arm against its pivotal bias so as to withdraw the lower finger and engage the upper finger. 4. An assembly according to claim 3, wherein the cam is in the form of a sleeve slidably mounted on the feed tube and which moves over the rocker arm upon its displacement along the feed tube. 5. An assembly according to any one of claims 1 to 4, wherein an abutment carried by the upper tube is engageable with the cam when the upper tube is displaced downwardly relative to the lower tube whereby the cam is then displaced downwardly on the feed tube to thereby control operation of the control mechanism. 6. An assembly according to claim 5, wherein the cam is subject to a spring bias which acts to move the cam to an upper stop position on the feed tube, the downwards displacement of the cam upon engagement by the abutment being in opposition to the spring bias which acts to return the cam towards its upper stop position when the upper tube is next displaced upwardly relative to the lower tube. |
BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a fastener driving tool assembly with a feed for feeding successive fasteners to a driving part of the assembly. More particularly the present invention relates to a "stand-up" driving tool assembly. 2. Description of the Prior Art
Sheets of roofing, decking, or other cladding are typically fastened to underlying structure using self drilling fasteners driven by a tool with a driving bit which engages the head of the fastener. The fastening of roofing sheeting may involve the installer standing on the sheeting in a squat position with the drive tool and bit held close to the surface of the sheeting. Fastening of roofing sheeting normally requires application of a significant number of fasteners, and fasteners applied in this way by an operator squatting on the sheeting can be very tiring for the operator. In order to alleviate this somewhat, "stand-up" fastener driving tools have been proposed and which enable the operator to drive the fastener from a standing up position rather than a squatting position.
Previously proposed stand-up tools have comprised an attachment to a conventional drive tool and which positions the lower end of a driving bit adjacent the sheeting when the operator is holding the tool while standing generally upright on the sheeting. The attachment also includes means for feeding fasteners to the operative zone of the driving bit. In one simple form, this may comprise a tube into which individual fasteners can be dropped by the operator in the standing position to slide down the tube for engagement by the driving bit. Although a simple system such as this is effective and results in a stand-up attachment which is relatively lightweight, easy to use and not cumbersome, it does require the operator to feed a fresh fastener into the tube after application of the preceding fastener. While there have been proposals to address this issue by the use of a magazine feed, certain prior proposals for this involve the use of collated fasteners, that is a series of fasteners mounted in succession along a strip which is fed into the magazine and which is advanced to present successive fasteners at the driving position. However the cost associated with collation is quite substantial whereby the cost of fasteners collated into a strip can be significantly more than that of equivalent fasteners supplied individually. Moreover, the presence of the magazine and associated collated fastener strip at the lower end of the attachment tends to make the attachment heavy and cumbersome to use and unless the collated fastener strip is properly confined it can "flap" when the attachment is moved and may cause damage to the surface finish of the sheeting by scratching or the like.
SUMMARY OF THE INVENTION
The present invention in its preferred embodiment relates to a stand-up tool assembly with a simple semi-automatic feed of fasteners not requiring the use of collation.
According to the present invention there is provided a fastener driving tool assembly for operation by an operator in a standing position, the assembly comprising upper and lower tubes telescopically mounted, a drive shaft extending through the tubes from a drive tool at the upper end of the upper tube, the drive shaft having a driving bit at its lower end, a housing at the lower end of the lower tube and having a chamber to receive a fastener to be driven into sheeting on which the operator is standing, the drive tool and upper tube being displaceable downwardly relative to the lower tube by the operator to place the driving bit in driving engagement with the head of the fastener, and a fastener feed system comprising a feed tube for storing individual fasteners in end to end relation along the tube, the lower end of the feed tube communicating with the chamber in the housing, and a control mechanism for releasably retaining the lowermost fastener in the feed tube and for releasing that fastener for passage into the chamber, operation of the control mechanism being responsive to movement of the upper tube to lower or raise the driving bit within the chamber, the control mechanism comprising a control cam slidably mounted on the feed tube and displaced by movement of the upper tube within the operational cycle of the assembly.
Advantageously the control mechanism comprises upper and lower fingers movable into the feed tube to an extent sufficient to engage the lowermost fastener within the tube and the next adjacent fastener and retractable to an extent sufficient to release the fasteners, the fingers being operable alternately by the control cam such that when the lower finger has been retracted to release the lowermost fastener for passage into the housing, the upper finger can engage the next adjacent fastener to retain that fastener and thereby the fasteners above that fastener, and when the upper finger is withdrawn to release that fastener the lower finger will act to releasably retain that fastener for the next cycle of operation.
In a preferred embodiment, the upper and lower fingers are carried by a rocker arm. In one practical arrangement, the rocker arm is spring biased to pivot the arm into a position in which the lower finger is in its retaining position and the upper finger in its released position and movement of the cam along the feed tube by movement of the upper tube downwardly causes pivotal movement of the rocker arm against its pivotal bias so as to withdraw the lower finger and engage the upper finger. Particularly advantageously, the cam is in the form of a sleeve slidably mounted on the feed tube and which moves over the rocker arm upon its displacement along the feed tube.
In one embodiment, the cam sleeve is disengaged from the rocker arm when the upper tube is in an upper position relative to the lower tube and downwards movement of the upper tube causes the cam sleeve to move over at least the upper part of the rocker arm. In an alternative embodiment the rocker arm may be substantially entirely enclosed within the cam sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Figure 1 is a side view, partially in section of a stand-up fastener driving tool assembly; Figure 1 A is an enlarged view showing a detail of Figure 1 ;
Figure 2 is an enlarged view showing the assembly during a different phase of its operational cycle; and
Figures 3A, 3B, 3C and 3D show somewhat more schematically the assembly in different stages of its operational cycle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The stand-up fastener driving tool assembly of a preferred embodiment of the invention comprises a rotary drive tool 2 of substantially conventional form and an attachment 4 applied to the tool to convert it for stand-up operation the attachment including a feed mechanism for semi-automatic feed of fasteners. The attachment 4 comprises upper and lower tubes 6, 8 telescopically mounted, with the lower tube 8 within the upper tube 6. The upper tube 6 is mounted at its upper end to the body of the drive tool 2. A rotary drive shaft 10 mounted in the chuck or collet of the drive tool 2 extends downwardly along the upper and lower tubes 6, 8 and carries a driving bit 12 at its lower end. The driving bit 12 is removably mounted on the drive shaft 10 so as to permit its ready replacement when worn. The telescopic arrangement of the two tubes 6, 8 is subject to an axial spring bias, for example by means of a compression coil spring (not shown) mounted within the upper tube 6 to bias the upper tube 6 to an upper or expanded position relative to the lower tube 8, and it is that position which is shown in Figure 1. In that position, the driving bit 12 is in a raised inoperative position.
The fastener applicator head is mounted at the lower end of the lower tube 8 and comprises a housing 20 having a chamber 22 aligned with the lower tube 8 for receiving a fastener to be applied. The lower edge of the housing 20 is intended to engage and rest upon the sheeting to be secured and for this purpose it is preferably provided with a profile complimentary to that of the sheeting. The housing 20 also supports the lower end of a fastener feed tube 24 leading into the chamber 22 via a passage 26 within the housing 20. The feed tube 24 extends alongside the tubes 6, 8 and is supported from the upper tube 6 by a slide coupling 26. The feed tube 24 is designed to be loaded with a series of individual fasteners, typically ten to twelve, which are put separately by the operator into the upper end of the tube 24 and rest in a stack along the length of the tube, with the tip end of one fastener resting on the head of the next adjacent lower fastener. A control mechanism is mounted to the lower part of the feed tube 24 to retain the stack of fasteners within the tube 24 and to allow just the lowermost fastener of the stack to move from the tube 24 into the housing 20 for subsequent movement into the drive chamber 22.
As can be best understood from the enlarged view of Figure 1A, the control mechanism comprises a rocker arm 30 having upper and lower inwardly projecting fingers 32, 34. The rocker arm 30 is pivotally biased (as shown by o-rings 36) into a position in which the lower finger 34 extends into the feed tube 24 to an extent sufficient to engage the head of the lowermost fastener of the stack and thereby retain that fastener within the lower end of the tube 24. In that condition the upper finger 32 is substantially withdrawn from the tube 24. This is the condition shown in Figures 1 and 1A which shows the lowermost fastener held by the lower finger 34 and the next adjacent upper fastener resting on the head of the lowermost fastener. Control of the rocker arm 30 in the manner to be described below causes the lower finger 34 to be withdrawn from the tube 24 at least to an extent sufficient to release the lowermost fastener, and the upper finger 32 to extend into the tube 24 to an extent sufficient to engage the head of the next adjacent fastener whereby to retain that fastener (and thereby the other fasteners above that one) in the tube 24 while the lowermost fastener has passed from the tube into the housing 20.
In the embodiment shown, control of the rocker arm 30 is effected by a cam sleeve 40 slidably mounted on the feed tube 24 and movable axially along the feed tube between an upper position as shown in Figures 1 and 1A in which the cam sleeve 40 is adjacent the upper end of the rocker arm 30, and lower positions in which the cam sleeve 40 has moved over the upper end of the rocker arm 30 and has pivoted it against its spring bias to cause its lower finger 34 to move to its released position and its upper finger 32 to move to its engaged position; this is the condition shown in Figure 2. The cam sleeve 40 is itself subject to an axial spring bias provided by a compression spring 42 to displace it to its upper position shown in Figures 1 and 1A and which is its "rest" position. Movement of the cam sleeve 40 from its upper to its lower positions to effect release and engagement of successive screws in the correct operational sequence is effected by simple interaction with the upper of the two telescopic tubes as will now be described. In the condition shown in Figures 1 and 1A the upper tube 6, subject to its axial spring bias, is in its upper position relative to the lower tube 8. In this condition, the driving bit 12 is above the chamber 22 in the driving head whereby a fastener can enter the chamber 22 via the passage 26 in the housing. Pressure applied by an operator on the drive tool 2 will push the upper tube 6 downwardly along the lower tube 8 against the spring bias and thereby move the driving bit 12 into engagement with the head of the fastener in the chamber 22 to thereby permit driving of the fastener when the drive tool 2 is actuated. The lower end of the upper tube 6 carries an abutment sleeve 46 which, when the upper tube 6 is moved downwardly, moves downwardly into engagement with a shoulder 40a of the cam sleeve 40 to thereby displace the cam sleeve 40 downwardly along the feed tube 24 against the bias of compression spring 42 to thereby pivot the rocker arm 30 so that its lower finger 34 releases the lowermost fastener in the tube and its upper finger 32 moves into the tube 24 by an extent sufficient to be engaged by the head of the next adjacent fastener whereby to retain that fastener (see Figure 2). Upon release of the lowermost fastener from the rocker arm 30 it will slide along the tube 24 into the transfer passage 26 but will not actually enter the drive chamber 22 as it is blocked from doing so by the presence of the driving bit 12 which is now in a lower driving position within the chamber 22. To initiate the next cycle of operation, when the fastener previously within the chamber 22 has been driven, pressure on the tool 2 is released whereby under its spring bias the upper tube 6 will move relative to the lower tube to its upper position, thereby withdrawing the driving bit 12 from the chamber 22 whereby the fastener previously released from the rocker arm 30 is able to move from the transfer passage 26 into the chamber 22 for driving at the next cycle of the tool. The movement of the upper tube 6 to its upper position enables the cam sleeve 40 to displace upwardly under the bias of spring 42 thereby moving out of engagement with the rocker arm 30 whereby, under the pivotal bias applied to the rocker arm, its upper finger 32 will withdraw from the feed tube 24 by an extent sufficient to cause release of the lowermost fastener held by that finger and movement of the lower finger 34 into the feed tube so as to engage the head of that same fastener when it has dropped to the level of the finger 34. The tool assembly is thereby set in a condition for the next operational cycle. The actions described above are illustrated more clearly in Figures 3A to 3C. In Figure 3A the tool assembly is in substantially the same condition as that of Figures 1 and 1 A with a fastener Fl within the drive chamber 22 for engagement by the driving bit 12 when the upper tube 6 is next pushed downwardly by the operator along the lower tube 8. The lowermost fastener F2 within the feed tube 24 is retained by the lower finger 34 of rocker arm 30 and the next adjacent fastener F3 is supported by engagement of its tip with the head of fastener F2. Other fasteners (not shown) within the feed tube 24 will be similarly supported seriatim. Figure 3B shows the condition in which the driving bit 12 is close to its lowest position within chamber 22 which corresponds to the position in which fastener Fl has been completely or substantially completely driven. In this condition cam sleeve 40 engaged by sleeve 46 has actuated rocker arm 30 to cause release of fastener F2 from lower finger 34 and engagement of the fastener F3 by upper finger 32. The released fastener F2 is thus freed to slide into transfer passage 26 but is blocked from moving into the drive chamber 22 by the presence of the driving bit 12. Figure 3C shows the condition in which the upper tube 6 has been raised partially to an extent sufficient to withdraw the abutment sleeve 46 from the cam sleeve 40 whereby the cam sleeve 40 has displaced under its spring bias whereby the rocker arm 30 has pivoted under its spring bias so that its lower finger 34 is now retaining fastener F3. In this condition which is not the fully raised condition of upper tube 6, the driving bit is still in a position in which it is blocking movement of the fastener F2 from transfer chamber 26 into drive chamber 22. Figure 3D shows the condition in which upper tube 6 is in its fully raised position or at least close to that position. Driving bit 12 is now raised sufficiently to permit passage of fastener F2 from the transfer chamber 26 to the drive chamber for application to the sheeting at the next cycle of operation of the tool. It is to be noted that as movement of the tube 6 to its upper position will result in the fastener already in the transfer chamber dropping into the drive chamber 22 upon withdrawal of the driving bit 12, the operator may choose not to initiate that action until the tool assembly has been repositioned on the sheeting for application of that fastener; accordingly, the operator would in that case hold the tool assembly so that the upper tube 6 remains in a lower position relative to the lower tube 8 while moving the tool assembly to the position required for application of that next fastener. Nevertheless, the operator may opt not to maintain the tube 6 at the lower position if it is desired for the next fastener to drop into the drive chamber 22 prior to repositioning the tools (or may leave the tube 6 in either the lower or upper position if it is not important whether the next fastener drops into the drive chamber 22 prior to repositioning the tool). Using this alternative procedure, the operator would then, after moving the tube 6 to its upper position, reposition the tool assembly on the sheeting for application of the next fastener.
The rocker arm 30 and its actuation by the cam sleeve 40 provides a robust mechanism capable of withstanding rough treatment which a tool of this type could typically experience on a building site. The use of the cam sleeve does permit the incorporation of two or more rocker arms distributed around the axis of the feed tube thereby providing a degree of redundancy to permit continuing operation of the control mechanism even if one of the rocker arms should break. In an alternative embodiment, an effect similar to that provided by the rocker arm with fingers which enter and withdraw from the feed tube upon pivotal movement of the arm could be achieved by spring-loaded fingers or pins controlled by movement of a cam sleeve or other cam along the feed tube in response to movement of the upper tube telescopically relative to the lower tube.
The embodiment has been described by way of example only and modifications are possible within the scope of the invention.