Driving tool

Abstract

The driving tool for installing fasteners in workpieces includes a motor operated driver, a clutch mechanism engageable with the driver, and an adapter including a wrenching mechanism and which connects to the driving tool and cooperates with the clutch mechanism to effectuate rotation of the wrenching mechanism. The adapter includes means to engage the clutch before the fastener engages the workpiece. The preferred means is a detent assembly which is secured to the main body of the adapter and has a detent ball which cooperates with an annular groove in the wrenching mechanism. The main body or an extension thereof of the adapter engages the workpiece prior to the fastener and as continued force is applied, the clutch mechanism is engaged. Thereafter, the detent overrides the groove permitting the wrenching mechanism and fastener to further advance and the fastener is driven into the workpiece. The adapter is adjustable for different length fasteners.

Description

FIELD OF THE INVENTION

My invention relates to driving tools and, more particularly, to adapters for driving tools for self-drilling and tapping fasteners.

DESCRIPTION OF THE PRIOR ART

There are a variety of known driving tools and adapters therefor for setting fasteners and in particular fasteners of the self-drilling and tapping type, hereinafter referred to as self-drilling. The majority of the tools perform two functions in common. First, the tools employ a clutching mechanism which is engageable with the driver to cause rotation of the wrenching mechanism which includes the socket; and second, the clutching mechanism is engaged by forcing the fastener against the workpiece to actuate the clutch. This latter common function has a substantial number of drawbacks.

The self-drilling fastener itself is not as efficient as a standard drill and is normally formed with a chisel-like point for penetrating the workpiece. However, the thickness of the web which forms the chisel-like point may vary appreciably from production lot to production lot or the point may be nonsymmetrical with respect to the fastener shank.. Both conditions create difficulties in driving the fastener. A poor performing self-drilling screw has a tendency to drift or walk from the point of intended application and this tendency is particularly increased with increased web thickness since substantial pressure must be placed on the screw to activate the clutch which in turn imparts rotation to the wrenching mechanism. Many applications for such self-drilling screws utilize prefinished metal sheets and scoring of a prefinished sheet is not acceptable to the building erector.

In addition, the fastener is normally held in alignment by a magnetized hex socket of the wrenching mechanism and if the driving tool is not held precisely perpendicular to the workpiece, the tendency for the drill screw to walk or drift is further aggrevated. The known performance of these tools results in the fastener manufacturer and/or the consumer rejecting substantial lots of self-tapping screws since a drill point which is only slightly defective will perform poorly with the known driving tools.

SUMMARY OF THE INVENTION

My invention overcomes the drawbacks of the known driving tool by having the adapter rather than the fastener contact the workpiece in order to actuate the wrenching mechanism. In addition, the tool is automatically squared with the workpiece to assure a proper alignment of the fastener relative to the workpiece. My invention also results in the fastener attaining driving speeds prior to engagement with the workpiece. My invention further provides for the fastener to be maintained in alignment by support means in two spaced locations to further insure proper installation. If the fastener does wobble during installation, the amount of wobble is normally less than the diameter of the fastener so the material is either removed or in the severest condition the scoring is covered by the fastener head. My invention can also be adjusted to accommodate different length fasteners.

My invention is an adapter for a driving tool in which the adapter bypasses the fastener to cause a wrenching mechanism to engage the clutch before the fastener engages the workpiece. A main body extensible within an outer housing of the adapter has connected to it a detent assembly which includes a detent ball operable in an annular groove on the wrenching mechanism. The main body or an extension thereof engages the workpiece and continued pressure forces the wrenching mechanism into operable engagement with the clutching mechanism. Thereafter the detent overrides the groove permitting the wrenching mechanism to advance toward the workpiece driving the fastener thereinto.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of the assembled tool;

FIG. 2 is an exploded view of the adapter;

FIG. 3 is a section through the adapter in its extended position;

FIG. 4 is a section through the adapter in a clutch engaging condition;

FIG. 5 is a section through the adapter when the detent overrides its mating groove;

FIG. 6 is a section through the adapter when the fastener is fully driven;

FIG. 7 is a section through the detent assembly; and

FIG. 8 is an elevation of a modified adjustment collar.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The driving tool, generally designated 10, comprises a motor driven driver 12 and an adapter 14 which is connected thereto, FIG. 1. The adapter 14 has four major components, namely the housing 16, the main body 18 which is slidably positioned within the housing 16, the wrenching mechanism 20 operable within the main body 18 and the detent assembly 34 operable between the main body 18 and the wrenching mechanism 20. The clutching mechanism is not shown in detail since the particular type of clutching mechanism does not form a part of this invention. The clutching mechanism is therefore shown diagramatically as box 80 for purposes of illustration. In existing tools the clutch mechanism is formed as an integral part of the driver or as an integral part of the adapter, and either arrangement is compatible with the inventive concept disclosed herein.

The relationship of the various parts of the adapter 14 is best seen in exploded FIG. 2. The housing 16 is tubular and internally threaded at both ends. Specifically, internal threads 22 at one end of housing 16 engage external threads (not shown) of the driver 12. Internal threads 24 at the other end of housing 16 engage the internal threads 48 of adjustment collar 46. Housing 16 includes an elongated slot 26 which extends a portion of the length of housing 16 in a direction parallel to the longitudinal axis thereof. Housing 16 is therefore rigidly secured to the driver 12.

The main body 18 is likewise tubular and is positioned within housing 16 so as to be slidable therein and extensible therefrom. Main body 18 includes an annular shoulder 28 along its rearward end and annular shoulder 28 engages the forward section of housing 16 to limit the forward movement of body 18 and maintain body 18 within the housing 16 in the extended position of body 18. The forward end of main body 18 includes external threads 30 which engage annular ring 44, which is internally threaded. A nonskid and nonmarring surface 56 is adhesively secured to the annular ring 44 and engages the workpiece surface 82. A clear-through central cylindrical opening 88 of body 18 accommodates the wrenching mechanism 20 and contains an annular shoulder 84 spaced slightly inward of the forward end to accommodate the washer of a fastener assembly.

A large coil spring 58 is positioned within housing 16 between the driver (not shown) and the shoulder 28 of main body 18. Coil 58 urges the main body 18 to the fully extended position, FIG. 3, after a fastener 74 is fully driven and the adapter 14 is removed from the workpiece surface 82.

An adjustment collar 46 is positioned over the main body 18 and threadably engages with the housing 16 as described hereinabove, FIG. 2. Collar 46 includes a plurality of elongated spaced slots 50 extending inward from the rear end thereof parallel to slot 26 of housing 16. The forward shoulder 86 of collar 48 includes indicia 52 which corresponds with indicia 54 on the main body 18. The indicia 52 and indicia 54 relate to the length of the fastener and when mating indicia are aligned, a specific slot 50 will be in registry with slot 26 of the housing 16 to accommodate the detent assembly 34.

A simplified adjustment collar 80 is illustrated in FIG. 8 where the annular ring 82 corresponds to ring 44 of the earlier embodiment. Ring 82 threadably engages main body 18 and therefore serves as an adjustment for different fastener lengths depending on the degree to which it is positioned along main body 18.

The wrenching mechanism 20, cylindrical in shape, is positioned within the opening 88 of the main body 18 for engagement with the clutching mechanism 80. Wrenching mechanism 20 includes a drive coupling 40 positioned at one end and engageable with the clutch mechanism 80. A hex socket 38 is recessed in the other end of wrenching mechanism 20 to accommodate the hex head 72 of a fastener 70. An annular groove 42 extends about the wrenching mechanism 20 intermediate its ends and perpendicular to the longitudinal axis thereof.

A detent assembly 34 includes a threaded body 60, a blind chamber 62 therein and a ball 64 adapted to cooperate with the blind chamber 62 and the groove 42 of the wrenching mechanism 20, FIG. 7. A coil spring 66 is positioned in the blind chamber to urge the ball 64 out of chamber 62 and into the groove 42. The threaded body 60 includes a screwdriver slot 68 at its upper end and the threaded body 60 threadably engages one of the threaded openings 32 in the main body 18. The various openings 32 are utilized for the different fastener lengths employed. This could also be accomplished by using different wrenching mechanisms for each fastener length or by utilizing a plurality of grooves 42. The threaded body 60 is also positioned within the slot 26 of housing 16 and the slot 50 of adjustment collar 46. In this manner the detent assembly 34 not only permits bypassing the fastener 70 to engage the clutch 80, as will be described hereinafter, but the detent assembly 34 also prevents relative rotative movement between the main body 18, housing 16 and adjustment collar 46.

A typical fastener 70 for use with the adapter 14 has a hex head 72 and a threaded shaft 74 which terminates in a drill point 76. A washer 78 is positioned on the fastener 70 in spaced relationship from the hex head 72.

The operation of my adapter is illustrated in FIGS. 3-6. The fastener 70 is manually positioned in the main body 18 so that the fastener head 72 fits in the accommodating socket 38 of the wrenching mechanism 20. At the same time, the washer 78 is limited by the annular shoulder 84 in the opening of the main body 18 to assure the spaced relationship from hex head 72 and thereby assure proper alignment. The driving tool 10 is then positioned against the workpiece surface 82 so that the nonskid surface 56 engages it. At this position, FIG. 3, the detent assembly 34 is in engagement with the groove 42 of the wrenching mechanism 20 and the drill point 76 is still internal of the main body 18.

As the operator exerts pressure to the driving tool 10, the main body 18 retracts into the housing 16 carrying with it the wrenching mechanism 20 by means of the detent assembly 34, FIG. 4. This retraction continues until the driving coupling 40 of the wrenching mechanism 20 engages the clutch to cause rotation of the wrenching mechanism 20 and fastener 70.

Thereafter the detent overrides the groove 42 as the ball 64 contracts the spring 62 within the blind chamber 66 of the threaded body 60, FIG. 5, and then the drill tip 76 penetrates the work surface. The force opposing the penetration of the fastner 70 into the workpiece and the continued pressure by the operator maintain the wrenching mechanism 20 in engagement with the clutch 80. The fastener 70 is driven fully into place and the clutch is disengaged through clutch mechanism 80 in the standard manner. Thereafter coil spring 58 urges the main body 18 to the fully extended position in which the detent assembly 34 again engages groove 42.

The adjusting collar 46 can be threaded into or out of the housing 16 or collar 80 can be threaded onto or out of main body 18 to accommodate different length fasteners for the respective embodiments. Likewise detent assembly 34 is threadably engaged in the proper opening 32 for the particular length fastener. Since fasteners are of standard lengths, this information is reflected on the respective indicia 52 and 54 so that mating indicia can be aligned for each given fastener length. A window can also be inserted in the main body 18 in the area of the hex socket 38 so the operator can visually see the loading of the fasteners.

Claims

I claim:

1. An adapter for a fastener driving tool in which a clutch mechanism is operable therebetween comprising:

A. a housing adapted for securement to the driving tool;

B. a main body having an opening therethrough slidably positioned within the housing and adapted for engagement with a workpiece and for extensible movement from the housing;

C. a wrenching mechanism positioned within the main body opening including a forward fastener engaging end and a rearward clutch engaging end and an annular groove thereabout intermediate said ends; and

D. a detent assembly operative between the main body and the groove in the socket member so that as the main body is urged from an extended position into the housing, the detent engages the groove to move the socket member into engagement with the clutch mechanism and continued movement of the main body into the housing causes the detent to override the groove and move relative to the wrenching mechanism.

2. The adapter of claim 1 wherein said housing includes a slot accommodating the detent assembly.

3. The adapter of claim 1, said detent assembly including a blind chamber housing threadably engaging through the main body, a detent ball cooperating with the chamber and said groove in the wrenching mechanism and a spring positioned in the chamber to urge the ball into said groove.

4. The adapter of claim 1 wherein the workpiece engaging portion of the main body comprises a nonskid surface.

5. The adapter of claim 1 including an adjustment collar engageable with the housing to form a stop for the main body as it advances into the housing.

6. The adapter of claim 1 wherein the main body includes an annular shoulder along the opening to accommodate a washer positioned on the fastener in spaced relationship from a fastener head to assure proper alignment of the fastener relative to the adapter and workpiece.

7. The adapter of claim 1 including a coil spring positioned in the housing to urge the main body into an extended position.

8. The adapter of claim 1 including an adjustment collar threadably engaged to the main body at an end thereof.

9. The adapter of claim 3 wherein the main body includes a plurality of spaced threaded openings to accommodate the detent assembly housing at various fastener length adjustments.

10. The adjustment collar of claim 5 including a plurality of slots spaced thereabout and positioned so one of said slots is in registry with the housing slot at a given adjustment to accommodate the detent assembly.

11. The adjustment collar of claim 7 including spaced indicia thereon indicating a fastener length and adapted to align with mating indicia on the main body to place an adjustment collar slot in registry with the housing slot for a given fastener length.

12. A driving tool and fastener combination comprising:

A. a motor operated driver;

B. a clutch mechanism engageable with the driver;

C. an adapter connected to the driver and comprising

a. a housing having a slot therein and adapted for securement to the driving tool;

b. a main body having an opening therethrough slidably positioned within the housing and adapted for engagement with a workpiece and for extensible movement from the housing;

c. a wrenching mechanism positioned within the main body opening including a forward fastener engaging socket end and a rearward clutch engaging end and an annular groove thereabout intermediate said ends;

d. a detent assembly cooperating with the slot in the housing and operative between the main body and the groove in the socket member;

D. a fastener having a head engageable with the socket end, a shank extending from the head and wholly within the main body opening and a washer slidably positioned on the shank and positioned within the main body opening in spaced relationship from the fastener head

whereby a forward pressure on the driving tool causes the socket member to engage the clutch before the fastener engages the workpiece.

13. The combination of claim 12 wherein the main body includes an annular shoulder positioned about the opening to accommodate the washer.