Fastener-driving tool

Abstract: A mechanism for controlling a fastener-driving tool comprises a workpiece contacting element (34), a tool-controlling element (40) movable conjointly with the workpiece-contacting element (34) over a limited range, a spool (60) having a threaded connection (38, 76) with the workpiece-contacting element (34) and a swivel connection (46, 76, 100) with the tool-controlling element (40) and having axial ribs (78) alternating with axial grooves (80), and a spool-restraining element (90) movable along a radial line between a spool-restraining position and a spool-releasing position and biased toward the spool-restraining position. The spool-restraining member (90) is arranged to restrain the spool (60) against rotating at the swivel and threaded connections by projecting into any given one of the grooves (80), when the workpiece-contacting element (34) is moved inwardly from an outer portion of the limited range but not when the workpiece-contacting element (34) is within the outer portion of its limited range.

Description: Conventionally, a fastener-driving tool, whether pneumatically powered or combustion-powered, has a nosepiece, through which fasteners are driven into workpieces, and is equipped with a tool-controlling mechanism including a workpiece-contacting element, which is movable inwardly toward the nosepiece and outwardly from the nosepiece. The tool-controlling mechanism may include a tool-controlling element, which is movable conjointly with the workpiece-contacting element over a limited range, the conjointly movable elements being biased outwardly toward an outer portion of the limited range. The tool-controlling mechanism is operative for controlling the tool so that the tool is enabled when the workpiece-contacting element contacts and is pressed firmly against a workpiece until the tool-controlling element inwardly to an inner portion of the limited range and so that the tool is disabled when the workpiece-contacting element is removed from the workpiece and is moved outwardly as biased from the inner portion of the limited range. As exemplified in Volkmann US-A-3,519,186, US-A-4,767,043, US-A-5,219,110, and US-A-5,385,286, it is known for the tool-controlling mechanism of a fastener-driving tool to be adjustable so as to permit the depth-of-drive to be adjusted. Herein, the depth-of-drive refers to the depth to which a fastener, such as a nail, can be driven by the fastener-driving tool. Generally, the tool-controlling mechanism may be adjusted so that the fastener may stand off the workpiece surface or so that the fastener may be countersunk below a workpiece surface. According to this invention a fastener-driving tool having a nosepiece and being equipped with a tool-controlling means including a workpiece-contacting element movable inwardly toward the nosepiece and outwardly from the nosepiece over a limited range and a tool-controlling element movable conjointly with the workpiece-contacting element, the conjointly movable elements being biased outwardly toward an outer portion of the limited range, for controlling the tool so that the tool is enabled when the workpiece-contacting element contacts and is pressed firmly against a workpiece to move the tool-controlling element inwardly to an inner portion of the limited range and so that the tool is disabled when the workpiece-contacting element is removed from the workpiece and moves outwards under its bias from the inner portion of the limited range, is characterised in that the tool-controlling means further comprises a spool defining an axis and connecting the tool-controlling element to the workpiece-contacting element, at a swivel connection between the spool and the tool-controlling element or the workpiece-contacting element and at a threaded connection between the spool and the other of the tool-controlling element or workpiece-contacting elements, and a spool-restraining element movable between a spool-restraining position and a spool-releasing position, biased toward the spool-restraining position, and arranged to restrain the spool against rotating at the swivel and threaded connections by engaging the spool when the workpiece-contacting element is moved inwardly from the outer portion of the limited range but not when the workpiece-contacting element is within the outer portion of the limited range. Preferably, the spool connects the tool-controlling element to the workpiece-contacting element, at a swivel connection between the spool and the tool-controlling element and at a threaded connection between the spool and the workpiece-contacting element. Preferably, the spool has a circumferentially spaced array of axial ribs alternating with axial grooves, and the spool-restraining element is movable between the spool-restraining position and the spool-releasing position, along a line intersecting the axis defined by the spool approximately at a right angle. Preferably, moreover, the spool-restraining element is arranged to restrain the spool against rotating at the swivel and threaded connections projecting into any given one of the grooves, between the ribs nearest to the given one of the grooves, when the workpiece-contacting element is moved inwardly from the outer portion of the limited range but not when the workpiece-contacting element is within the outer portion of the limited range. A particular embodiment of a tool in accordance with this invention will now be described with reference to the accompanying drawings; in which:- Figure 1 is a partly broken away, perspective view of a fastener-driving tool; Figure 2 is a fragmentary, partly sectioned, elevation of the tool-controlling mechanism and a nosepiece of the fastener-driving tool, with the tool-controlling mechanism in a tool-disabling position and with a workpiece-contacting element contacting a workpiece; Figure 3 is a fragmentary, sectional view taken along line 3--3 of Figure 2 in a direction indicated by arrows; Figures 4 and 5 are views derived similarly from Figure 2, showing the tool-controlling mechanism in a tool-enabling position, and showing the tool-controlling mechanism as adjusted respectively so that a driven fastener may stand off the workpiece surface, as shown in Figure 4 and so that a driven fastener may be generally flush with a workpiece surface, as shown in Figure 5; Figure 6 is a fragmentary, sectional view taken along line 6--6 of Figure 4, in a direction indicated by arrows; Figure 7 is an exploded, perspective view of some of the elements of the tool-controlling mechanism; Figure 8, on an enlarged scale, is an upper end view of a spool, which is one of the elements of the tool-controlling mechanism; Figure 9 is a sectional view taken along line 9--9 of Figure 8, in a direction indicated by arrows; and, Figure 10 is an enlargement of an upper portion of the spool, as shown in Figure 9. As shown in Figure 1, a fastener-driving tool 10 having a nosepiece 12, through which nails or other fasteners are driven into a workpiece, is equipped with a tool-controlling mechanism 20 constituting a preferred embodiment of this invention. The tool-controlling mechanism 20 is adjustable, in a manner described below, so as to permit the depth-of-drive to be adjusted, i.e. the depth to which a fastener, such as a nail, can be driven by the fastener-driving tool 10. As shown, the tool 10 is a pneumatically powered, nail-driving tool. A tool-controlling mechanism similar to the mechanism 20 would be also useful in a fastener-driving tool of a different type, such as a pneumatically powered, staple driving tool, a combustion-powered, nail-driving tool, or a combustion-powered, staple-driving tool. Broadly, the a tool-controlling mechanism 20 includes a workpiece-contacting element 30, which is movable inwardly (upwardly as shown) toward the nosepiece 12 and outwardly (downwardly as shown) from the nosepiece 12 over a limited range, and a tool-controlling element 40, which is movable conjointly with the workpiece-contacting element 30. The workpiece-contacting element 30 has a longer leg 32, a looped foot 34, and a shorter leg 36, which has a threaded end 38. The looped foot 34 joins the longer leg 32 and the shorter leg 36. The tool-controlling element 40 has a hooked end 42 and a grooved end 44, which has an annular groove 46. The conjointly movable elements 30, 40, are biased outwardly (downwardly as shown) toward an outer portion of the limited range, by a compression spring 50 bearing against a movable bracket 52, which is attached to the hooked end 42 of the tool-controlling element 40, as by a rivet 54. The tool-controlling mechanism 20, which includes the compression spring 50 and the movable bracket 52, is used for controlling the tool 10 in a known manner, which is outside the scope of this invention, so that the tool 10 is enabled when the workpiece-contacting element 30 contacts and is pressed firmly against a workpiece W (see Figures 2, 5, 6, and 7) until the tool-controlling element 40 is moved inwardly (upwardly as shown) to an inner portion of the limited range and so that the tool 10 is disabled when the workpiece-contacting element 30 is removed from the workpiece W and is moved outwardly (downwardly as shown) as biased from the inner portion of the limited range. According to this invention, the tool-controlling mechanism 20 further comprises a spool 60 and a spool-restraining element 90. The spool 60, which defines an axis, connects the tool-controlling element 40 to the workpiece-contacting element 30, at a swivel connection 62 between the spool 60 and grooved end 44 of the tool-controlling element and at a threaded connection 64 between the spool 60 and the workpiece-contacting element 30. The spool 60 has a central bore 70 having a grooved end 72, which has an annular groove 74, into which the grooved end 44 of the tool-controlling element 40 is inserted, and in which the grooved end 44 is retained by a polymeric ring 100 disposed within the annular groove 46 of the grooved end 44 and within the annular groove 74, and a threaded end 76, into which the threaded end 38 of the workpiece-contacting element 30 is threaded to an adjustable depth. The spool 60 has a circumferential array of axial ribs 78 alternating with axial grooves 80. The spool 60 is disposed so that some of the ribs 78 are accessible to a finger of a user for rotating the spool 60 so as to vary the depth of threading of the threaded end 38 of the workpiece-contacting element 30 into the threaded end 76 of the central bore 70 of the spool 60. The spool-restraining element 90, which has a flat, inner end 92 and a frusto-conical, outer end 94, is mounted within a socket 96 in the nosepiece 12 so as to be linearly movable between a spool-restraining position and a spool-releasing position, along a line intersecting the axis defined by the spool 60 approximately at a right angle. The spool-restraining element 90 is biased toward the spool-restraining position by a coiled spring 98 (see Figure 6) compressed between the inner end 92 and a retainer 110 mounted within the socket 96. The spool-restraining element 90 is arranged to restrain the spool 60 against rotating at the swivel connection 62 and at the threaded connection 64 when the workpiece-contacting element 30 is moved inwardly from the outer portion of the Limited range but not when the workpiece-contacting element 30 is within the outer portion of the limited range. As shown in Figure 4, if the spool 60 is rotated so that the threaded end 38 of the workpiece-contacting element 30 is threaded fully into the threaded end 76 of the central bore 70 of the spool 60, the nosepiece 12 remains spaced by a distance D from the workpiece W when the fastener-driving tool 10 is enabled, i.e. when the looped foot 34 of the workpiece-contacting element 30 is pressed firmly against the workpiece W until the tool-controlling element 40 is moved inwardly (upwardly as shown) to an inner portion of the limited range of conjoint movement of the conjointly movable elements 30, 40. Thus, when the fastener-driving tool 10 is operated to drive a fastener, such as the nail N shown in broken Lines, into the workpiece W, the fastener is driven so as to stand off the workpiece surface by the same distance D. As shown in Figure 5, if the spool 60 is rotated so that the threaded end 38 of the workpiece-contacting element 30 is threaded partially and by a suitable distance into the threaded end 76 of the central bore 70 of the spool 60, the nosepiece 12 contacts the workpiece W when the fastener-driving tool 10 is enabled. Thus, when the fastener-driving tool 10 is operated to drive a fastener, such as the nail N shown in broken lines, into the workpiece W, the fastener is driven so as to be generally flush with the workpiece surface. Likewise, if the spool 60 is rotated so that the threaded end 38 of the workpiece-contacting element 30 is threaded further but not fully into the threaded end 76 of the central bore 70 of the spool 60, a fastener, such as the nail N, can be driven into the workpiece W so as to stand off the workpiece surface by a distance less than the distance D indicated in Figure 4. As shown in Figure 2, when the conjointly movable elements 30, 40, are in an outer portion of the limited range of conjoint movement of such elements 30, 40, the spool-restraining element 90 is inward of the spool 60 and does not engage the spool 60, which can rotate at the swivel connection 62 and at the threaded connection 64 without interference with the spool-restraining element 90. Thus, when the fastener-driving tool 10 is in a toolbox or on a workbench, the depth-of-drive can be easily adjusted by rotating the spool 60 relative to the conjointly movable elements 30, 40, without interference therewith. The ribs 78 facilitate rotating the spool 60 relative thereto. As shown in Figures 4, 5, and 6, when the looped foot 34 of the workpiece-contacting element 30 is pressed firmly against the workpiece W until the conjointly movable elements 30, 40, are moved inwardly (upwardly as shown) from the outer portion of the limited range of conjoint movement of such elements 30, 40, the spool-restraining element 90 projects into a given one of the grooves 80, between the ribs 78 nearest to the given one of the ribs 80. Thus, when the fastener-driving tool 10 is operated, the spool-restraining element 90 restrains the spool 60 against rotating. However, the spool 90 may exhibit a very small rotation, if and as required to centre the spool-restraining element 90 between the ribs 78 nearest to the given one of the grooves 80. Although the spool 60 is restrained against rotating, the spool 60 could be forcibly rotated, whereupon the coiled spring 98 biasing the spool-restraining element 90 would be compressed as the spool-restraining element 90 would be cammed over each rib 80 passing by the spool-restraining element 90.

Claims: A fastener-driving tool having a nosepiece (12) and being equipped with a tool-controlling means (20) including a workpiece-contacting element (34) movable inwardly toward the nosepiece (12) and outwardly from the nosepiece (12) over a limited range and a tool-controlling element (40) movable conjointly with the workpiece-contacting element (34), the conjointly movable elements (34,36) being biased outwardly toward an outer portion of the limited range, for controlling the tool so that the tool is enabled when the workpiece-contacting element (34) contacts and is pressed firmly against a workpiece to move the tool-controlling element (40) inwardly to an inner portion of the limited range and so that the tool is disabled when the workpiece-contacting element (34) is removed from the workpiece and moves outwards under its bias from the inner portion of the limited range, wherein the tool-controlling means further comprises a spool (60) defining an axis and connecting the tool-controlling element (40) to the workpiece-contacting element (34), at a swivel connection (46, 74, 100) between the spool (60) and the tool-controlling element (40) or the workpiece-contacting element (34) and at a threaded connection (38, 76) between the spool and the other of the tool-controlling element (40) or workpiece-contacting elements (34), and a spool-restraining element (90) movable between a spool-restraining position and a spool-releasing position, biased toward the spool-restraining position, and arranged to restrain the spool (60) against rotating at the swivel (46, 74, 100) and threaded connections (38, 76) by engaging the spool (60) when the workpiece-contacting element (34) is moved inwardly from the outer portion of the limited range, characterized in that when the workpiece-contacting element (34) is within the outer portion of the limited range the spool-restraining element (90) does not engage the spool (60). A tool according to claim 1, wherein the spool (60) has a circumferentially spaced array of axial ribs (78) alternating with axial grooves (80), and wherein the spool-restraining element (90) is arranged to restrain the spool (60) by projecting into any given one of the grooves (80). A tool according to claim 1 or 2 wherein the spool-restraining element (90) is movable along a line intersecting the axis defined by the spool (60). A tool according to claim 3, wherein the spool-restraining element (90) is movable substantially normally to the axis of the spool (60). A tool according to any one of the preceding claims, wherein the tool controlling element (40) is connected to the spool (60) by the swivel (46, 76, 100) and the workpiece contacting element (34) is connected to the spool (60) by a screwthread (38,76).

Inventors: HOWELL SCOTT, SHKOLNIKOV YURY, VAN ERDEN DONALD, HOWELL, SCOTT, SHKOLNIKOV, YURY, VAN ERDEN, DONALD
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1997
Main classification: B25C1
IPC codes: B25C1, B25C7