US3172121A - Electrically operated fastener driving tool - Google Patents

Description

March 9, 1965 R. H. DoYLE E'rAl. l

ELECTRICALLY OPERATED FASTENER DRIVING Toor.

March 9, 1965 R. H. DoYLE ETAL- 3,172,121

ELECTRICALLY OPERATED FASTENER DRIVING TOOL 2 Sheets-Sheet 2 Filed April 1, 1963 wwbm Num..

United States Patent O 3,172,121 ELECTREQALLY (BPERATED FASTENER BREWING TL Richard H. Doyle, Mount Prospect, and Leroy N. Hermann, St. Charles, lll., assiguors to Fastener Corporation, Franklin Paris, lll., a corporation of illinois Filed Apr. 1, 1963, Ser. No. $19,427 o Claims. (Cl. 1--49) This invention relates to an electrically operated power unit and, more particularly, to an electrically operated, portable fastener driving tool. This application is a continuation-in-part of a copending application of Richard Doyle et al., Serial No. 161,651, filed December 22, 1961, now Patent No. 3,141,171, issued July 21, 1964.

Pneumatically operated tools for driving fasteners, such as staples or nails, in a single power stroke have found extensive acceptance in industrial and some building applications in which the number of tools in use is large enough to justify the investment required for air compressing facilities, either stationary or mobile. However, a considerable field of application remains in which power operated fastener driving tools cannot be used because of the cost and difficulty of providing a suitably flexible system of supplying compressed air.

The virtually universal availability of electric power indicates that many of the factors limiting an expansion in the use of power operated fastener driving tools could be overcome with electrically operated fastener driving tools. A portable fastener driving tool operated by electric power is shown in the above-identied application and in another copending application of Richard H. Doyle et al., Serial No. 161,727, filed December 22, 1961. ln the latter application, a winding for operating a magnetic armature that actuates a fastener driving element or blade is energized for no more than one cycle of an alternating current or undulating potential to provide a single power stroke during which the fastener is driven. The heating to which the winding means and the tool housing are subjected in a tool of this type is sharply reduced from that encountered in conventional electric tools because of the very short interval during which the winding means is energized. However, even with this improved type of tool, undesirable heating of the winding, housing, and control components can occur in certain applications.

Accordingly, one object of this invention is to provide a new and improved electrically operated power unit. Y

Another object is to provide a new and improved electrically operated tool for driving fasteners.

Another object is to provide an electrically operated fastener driving .tool including new and improved cooling means.

A further object is to provide a fastener driving tool in which fluid conveying means are formed adjacent an operating winding andin which air displacing means are actuated by the operation of a blade driving armature to move a cooling fluid through the fluid conveying means.

Another object is to provide an electrically operate` fastener driving toolv including new and improved means for mounting an operating winding in a cavity in a housing for the tool.

Another object is to provide a fastener driving tool including means for mounting an operating winding in a ice tool housing to permit its removal for maintenance or replacement.

ln accordance with these and many other objects, an embodiment of the invention comprises an electrically operated, portable fastener driving tool including a housing having a forward or head portion and a rearwardly extending hollow handle portion. The head portion includes a cavity and is secured at its lower end to aL nosepiece assembly forming a drive track to which staples or other fasteners are successively supplied by a magazine assembly connected between the head portion and the handle portion. A winding means having an axially extending opening is disposed in the lower end of the cavity with the axial opening aligned with the drive track. The winding means is supported in a spaced relation to the adjacent wall of the cavity to provide one or a plurality of fluid conveying means that communicate both with the remainder of the cavity and with the atmosphere through ports or outlets formed in the housing.

A magnetic armature is slidably mounted in the axial opening in the winding and is connected at its lower end to a fastener driving blade that is slidably received within the drive track. Toe upper end of the armature means is secured to an air displacing means that is slidably mounted in a cylindrical upper portion of the cavity. Thus, whenever the winding means is energized to aetuate the armature, the air displacing means produces a flow of air 'through the fluid conveying means to cool the winding. Further, the mounting of the winding means in a spaced position from the housing prevents the direct transmission of heat from. the winding to the remaining components of the tool.

A control circuit for controlling the energizationof the winding means is disposed in the hollow handle of the housing and includes a manually actuated switch which is operated whenever the tool is to be operated. ln one embodiment of the invention, the hollow handle is sealed off from communication with the cavity in the head portion with a layer of heat insulating material disposed between the housing and handle to reduce any heating of the handle occasioned by heat generated by, the winding means. ln another embodiment, the cavity in the head portion and the interior of the hollow handle in which the control components are disposed are placed in fluid cornmunication so that the actuation of the air displacing means in response to the operation of the tool produces a flow of coolingair through the hollow handle to cool the control components therein and to prevent excessive heating of the handle portion of the housing.

Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the drawings, in which:

FIG. 1 is a sectional View of an electrically operate-z fastener driving tool embodying the present invention;

FlG. 2 is a fragmentary elevational view of a portion of the tool shown in FIG'. l

FIG. 3 isa sectional view taken along line 3 3 in FlG. l;

FIG. 4 is a fragmentary sectional view of an electrically operated fastener driving tool forming a second embodiment of the invention;

FlG. 5 is a sectional view taken along line 5-5 in FIG. 4; and FIFIG. 6 is a sectional view taken along line 6-6 in Referring nowmore specifically to FIGS. 1-3 of the drawings, therein is disclosed an electrically operated, portable fastener driving tool which is indicated generally as 100 and which includes :a housing 102 having a forward or head portion 102a and a rearwardly extending hollow handle 104. The head portion 102a defines a cavity 106 in lthe lower end of which is disposed a winding means 108 having an axially extending opening 110 in which is slidably mounted a magnetic armature 112. A fastener driving blade 114 is secured to the lower end of the armature means 112 and is slidably received within a drive track 116a formed in a nosepiece assembly 116 that is carried on the lower end of the head portion 10211. A magazine assembly indicated generally as 118 which is connected between the nosepiece assembly 116 and a rearwardly and downwardly extending portion 104C of the hollow handle 104 successively supplies fasteners, such as staples, to the drive track 11601 to be driven by the fastener driving blade 114.

The winding means 108 is selectively energized under the control of a power supply circuit 120, the operation of which is controlled by a manually actuated switch assembly indicated generally as 122. When the switch assembly 122 is manually actuated, the power supply control circuit 120 energizes the winding 108 to drive the armature 112 downwardly through a single power stroke during which the blade 114 engages and drives the fastener supplied by the magazine assembly 118. The armature 112 and the blade 114 are returned to their normal position by suitable return means. During both the downwardly directed power stroke and the return of the armature 112 to its normal position, lan air displacing means in the upper portion of the cavity 106 forces air around the winding and through the hollow handle 104 to cool the winding 108 and the control components mounted in the handle 104.

Referring now more specically to the construction of the housing 102, this member is preferably formed of a nonmagnetic metal and includes the forward or head portion 102a dening the cavity 106. The lower end of the head portion 102a is provided with a generally cylindrical opening 124 in which is movably mounted a generally cylindrical structure 116b forming a part of the nosepiece assembly 116. The structure 116k is provided with a transversely extending passageway 126 in communication with an enlarged portion in the drive track 116a to provide means for exhausting air entrapped below the armature 112 when it moves downwardly during a power stroke. A resilient bumper 128 for cushioning the termination of the power stroke of the armature 112 is disposed within a recess 130 in the structure 116b.

The upper end of the head portion 102:1 is provided with an opening 132 of a diameter at least as great as the winding means 108. The opening 132 is closed by a removable closure cap 134 that is secured i-n position by a plurality of threaded fasteners 136. The cap 134 includes a port or passageway 136 partially covered by a baffle 138 that places the upper end of the cavity 106 in communication with the atmosphere.

The winding means 108 consists of a plurality of turns of copper wire formed in a generally annular configuration to define the axial opening 110 and having an outer surface that is tapered inwardly and downwardly at its lower end. The winding means is covered or potted in a dielectric material 140 that may be metal filled to facilitate the transmission of heat from the winding 108. The lower end of the dielectric material 140 is provided with a bossed portion 140a that is received within the circular opening 124 in the lower end of the head portion 10211, and the upper end of the dielectric material 140 is provided with an upper bossed portion 140b. l To support the winding means 108 in a centrally disposed position in the lower end of the cavity 106 spaced from the walls of the head portion 102a so as to provide a generally annular air or fluid conveying space 142 surrounding the winding 108, the upper bossed portion 1401; is disposed within an inner opening 144 (FIG. 3) in a spider structure or means 146. The spider construction 146 i-ncludes an inner circular member 14611 connected to an outer circular member 146b by a plurality of radially extending spokes 146C. A removable fastening means 148 comprising a resilient arc or ring seated in a slot 150 inthe inner wall of the head portion 102:1 is disposed above and bears against the outer annular ring 146]) to detachably mount the `spider construction 146 and, thus, the winding means 108 in its desired position. When the locking means 148 and the spider 146 are removed after removing the closure cap 134, the winding means 108 can be removed from the housing 102 through the top opening 132.

The fluid conveying means or space 142 surrounding the winding means 108 provides means for moving a cooling fluid such as air, adjacent the winding 108 to carry off heat generated by the operation of the tool 100. The lower end of the space or tiuid conveying means 142 is placed in communication with the atmosphere by a plurality of ports or passageways 152 formed in the lower end of the head portion 10211. The upper end of the air conveying space 142 is placed in communication with the lower end of the cavity 106 by a plurality of openings 154 formed between adjacent spokes 146e in the spider construction 146.

The wall `of the head portion 102e immediately adjacent the winding means 108 is provided with a vertical- 1y extending slot 156 extending throughout the length of the winding means 108 to prevent the portion of the electrically conductive housing 102 adjacent the winding 108 from operating as a shorted turn or lag coil. Without the slot 156, the part of the head portion 102a disposed adjacent the coil 108 would operate as a single electrically conductive turn which, when the energization of the winding means 108 is terminated at the end of a power stroke, would retard the collapse of the ilux field and delay the return of the armature 112 to its normal position.

The armature means 112 is shown as comprising a single or integral cylindrical body of magnetic material, although it can be constructed of a plurality of parts. The upper end of the fastener driving element or blade 114 is secured to a lower end of the armature 112 by a transversely extending pin 158. A washer or ring 160, preferably formed of Teflonj is carried on the lower end of the armature 112 to provide a low friction bearing surface between the wall of the axial opening and the armature 112.

The upper end of the armature 112 is connected to fluid or air displacing means for circulating a cooling fluid through the space 142 surrounding the winding means 108. More speciiically, this air displacing means is provided by a somewhat flexible and annular vane or pumping element 162 preferably formed of sheet metal which is mounted on the armature 112 and biased into engagement with a flanged portion 11251 on its upper end by a compression spring 164 interposed between the inner edge of the vane 162 and the junction of the inner Wall of the head portion 102e and the upper surface of the locking means 148. The outer circular edge of the element 162 carries a resilient sealing element 166 that slidably engages the cylindrical upper portion of the cavity 106. The spring 164 not only biases the vane 162 against the flanged portion 112a of the armature 112 but also provides an armature return means for normally biasing the upper end of the armature 112 against an annular resilvient bumper or stop member 168 carried on the closure cap 134.

When the armature 112 is moved downwardly against the action of the spring 164, the vane 162 moves downwardly to force air in the cavity 106 downwardly through the fluid conveying means 142 and outwardly to the atmosphere through the ports 152, while drawing air into the upper end of the cavity 166 through the port or passageway 136. When the armature is moved upwardly by the spring 164 at the end of the driving stroke, the corresponding movement of the air displacing means 162 draws cooling air into the cavity 166 through the conveying space 142 and the ports 152 and discharges air from the upper end of the cavity 106 through the passageway 136.

The control components, including the power supply unit 12@ and the manually actuated switching assembly 122, are mounted within a cavity 170 formed by the hollow handle 1h41 and a recessed area or hollow formed in a rearwardly projecting portion 1Mb of the housing 102. The handle 1114 is preferably formed of one or ltwo pieces of a plastic material, and its forward end is opened and provided with two forwardly projecting side walls 164e that are secured to the rearwardly projecting portion 1021) of the housing 162 by a plurality of threaded fasteners 172. The power supply circuit 12d is mounted within the cavity 17d and can be supported therein by a plurality of ribs or projecting portions 1Mb formed integral with rthe hollow handle 1li/l. This circuit can be of a conventional design or one oi the improved circuits shown in the copending application identified above. The control circuit 126 is provided with power from a iline cord 17d which is adapted to be connected to a conventional source of alternating current potential and which passes through a strain relief element 176 to be secured to the input terminals of the control circuit 121). The control input terminals of the circuit 121i are connected to the manually actuated switching assembly 122, and the output terminals are connected to the winding 16S by conductors which pass through an opening 17S in the housing 1112. The opening 178 also places the cavity 17'@` in communication with the cavity 166 through the openings 154 in the spider structure 146.

The manually actuated switching assembly 122 includes an enclosed or sealed switch unit 169 having an operating plunger 162 that is adapted to be engaged and operated by a plunger 13d-that is slidably mounted in a sleeve 186 carried on the rearwardly projecting portion 1612!: of the housing. The plunger 134 is urged toward the operating plunger 182 by a compression spring 1S@ that is interposed at the head of the plunger 184 and a stem 19@ which is also slidably mounted within the sleeve 136 and which is biased into engagement with the upper surface of a trigger element 192 by a compression spring 194. The trigger 192 is pivotally mounted on a supporting bracket 196 by a pivot pin 197, the bracket 196 being carried on the housing 1112.

rlhe handle 1M is also provided with the downwardly extending portion 104C to which the rear end of the magazine assembly 113 is pivotally connected by a pivot pin 19d. Since the nosepiece structure 11619 is slidably mounted in the opening 12d in the housing 1652 and the rear end of the magazine assembly 118 is pivotally mounted on the shaft or pin 19S, the magazine assembly 118 and the nosepiece construction 116 are capable of a limited degree of pivotal movement relative to the housing 162 to provide means for absorbing recoil forces produced when the tool 1li@ is operated. The magazine assembly 116 is biased against the nosepiece construction 116]) by the force of a spring 19de acting between the pivot pin 19S and a bracket portion 198]). The rearwardly extending portion 194e of the handle 1114 can also be provided with a port or opening 199 that connects the atmosphere to the cavity 176. Since Vthe cavity 171i communicates with the atmosphere through the opening 199 and vwith the cavity 166 through the opening 178, the operation of the armature 112 and the consequent displacement of the air displacing means 162 produces a tlow of air through the cavity 171i to cool the handle 1li-i and the components therein.

When the tool is to be operated, the lower end of the nosepiece assembly 116 is placed against the workpiece and the trigger 192 is pivoted in a counterclockwise direction about the shaft 197 to move the stem 196 and the plungers 184 and 182 upwardly to actuate the sealed switch unit 180. T he switch unit 161B controls the power supply unit or circuit 121i so that the winding means 103 is connected directly across the potential source supplied by the line cord 17d to energize the winding means 1138 for a selected period of time such as a half cycle of an alternating current potential. When the winding 168 is energized, the armature 112 moves downwardly against the action of the compression spring 16d so that the lower end of the driver blade 112 engages and drives a fastener supplied to the drive track 11651 by the magazine assembly 1155, the downward movement of the armature 112 being terminated by engagement with the resilient bumper 12S. During this downward movement, the vane 162 moves downwardly within the cylindrical portion of the cavity 166 to force the air entrapped below the vane downwardly through the air conveying space 142 and into the atmosphere through the ports 152. Similarly, a portion of the air disposed in the cavity 1116 below the vane 162 is forced through the opening 17S and the cavity 176 to be expelled to the atmosphere through the port 199.

When the energization of the winding 163 is terminated, the compression spring 164i moves the vane 162 and the armature 112 upwardly until the anged portion 112er at the upper end of the armature 112 engages the resilient stop means 16S. During this movement of the vane 162, ambient air from the atmosphere is drawn into the air conveying space 142 through the ports 152 and into the cavity 17 il through the port 199. Thus, during each cycle of operation of the tool 11st), air is moved through the air conveying means 142 and the cavity 17@ to cool the Winding 1118 and the components of the control or power supply circuit 120.

Whenever the control components in the cavity 176 require maintenance or replacement, the magazine assembly 1153 is disconnected from the handle 11M, and the threaded fasteners 172 are removed to permit the handle 1114 to move rearwardly relative to the head portion 1412. When the handle 1M is displaced, the control circuit 120 can be removed through the opening in the forward end of the handle 1M. In addition, the sealed switch unit 18d and the operating mechanism therefor can be serviced through the rearwardly opening recess in the portion 16219 of the housing 1192.

In the event that it becomes necessary to replace or repair any of the drive components of the tool 161B, the threaded fasteners 136 can be removed to permit the removal of the closure cap 11i/1. This permits the air displacing vane or pump element 162 to be removed through the top opening 132 of the housing 1112 together with the armature 112, the drive blade 1141 and the compression spring 164. When the winding 108 is to be removed or replaced, the ends of the resilient locking member 146 are moved inwardly toward each other unit until this element can be displaced from the groove 156 and removed through the top opening 132. The spider structure 146 and the winding means 168 can now be removed through the top opening 152.

When the winding means 1113 is replaced, the intertting engagement of the lower boss 146o with the circular opening 124 and the cooperation of the spider structure 146 with the inner wall of the head portion 162:1 and the upper boss 146k insures that the winding means 16? is properly located spaced from the walls of the head portion 1112er to provide the air conveying space 142. The winding 161i is secured in its adjusted position in which it is also properly aligned with the drive track 116e by snapping the fastening means 1h13 into the recess or groove 1511. The remaining components can then be replaced through the top opening 132 after which the closure cap 134 is secured in position by the threaded asterers 136.

FIGS. 4-6 of the drawings illustrate an electrically operated stapler or tacker 200 which embodies the present invention and which is similar to the tool 100. The stapler 200 includes new and improved means for cooling the operating winding means in the stapler as well as novel means for insuring that the drive track of the stapler remains in engagement with a workpiece in spite of recoil. The tacker 200 comprises a housing formed by a generally cylindrical head portion 202 to which is secured a separate and rearwardly extending handle 204. The tacker 200, which can be operated by the control means, described in the above-identified copending applications, includes a winding means 206 disposed in the housing l202 and having an axially extending opening 202 in which is slidably disposed the lower end of a magnetic armature 210 to which the upper end of a fastener driving blade 212 is secured by a pin 213. The lower end of the driver blade 212 is slidably mounted in a drive track 214 formed in a nosepiece assembly 216. Suitable fasteners, such as staples or nails, are supplied to the drive track 214 by a magazine assembly, indicated generally as 210, which is rigidly secured to the nosepiece assembly 216 and which is pivotally mounted to a rear portion 204e! of the handle 204.

When the tool 200 is operated, as by the actuation of switch means (not shown) carried on the handle 204, the Winding 206 is energized to move the armature 210 and the connected driver blade 212 downwardly so that the blade 212 engages and drives a fastener supplied by the magazine assembly 210. During this downward movement, a vane or air impelling means secured to the armature 210 draws ambient air into the interior of the housing 202 through openings in an upper portion thereof and forces air downwardly around the outer surface of the winding 206 which is spaced from the housing 202. This air is discharged through openings in the lower end of the housing 202.

To provide means for insuring that the nosepiece assembly 216 remains in engagement with the workpiece during the fastener driving operation, the pivoted connection of this assembly and the magazine assembly 218 to the handle 204 is utilized. When the tool 200 is to be operated, the nosepiece assembly 216 is placed against the workpiece, and this component and the magazine assembly 218 are pivoted relative to the remainder of the tool. Thus, any recoil produced by the operation of the tool can be absorbed by displacing the housing 202 and the handle 204 relative to the assemblies 216 and 218 which remain in position so that the nosepiece assembly 216 contacts the workpiece.

Referring now more specifically to the housing 202, this housing is generally cylindrical in form and preterably is fabricated from a nonmagnetic material. The open upper end of the housing 202 is closed by a cover 220, and the open lower end of this housing is closed by a nonmagnetic member 222. The winding 206, which is similar to the winding 100 provided in the tool 100, is disposed in the lower end of the housing 202 resting on a resilient element 224 that engages the lower end of the armature 210 at the end of its power stroke to cushion the termination of the power stroke, The winding 206 is secured in position by a ring 226. To prevent the lower portion of the housing 202 surrounding the coil 206 `from providing the effect of a shorted turn or lag coil, this portion of the housing 202 is provided with one or more longitudinally extending and circumferentially spaced slots 223.

To provide means for cooling the winding 206, this winding is supported within the lower end of the housing 202 spaced from engagement therewith so that a somewhat annular passage or air conveying means 230 is provided interposed between the housing 202 and the winding 206 through which air can be moved. The passageway or space 230 communicates with the plurality of slots 228 and with a plurality of openings 232 formed in the lower end of `the member 202. The `winding 206 is held in a position spaced from the inner wall of the lower portion of the housing member 202 by a plurality of generally L-shaped spacers 234 which are interposed between the win-ding 206 and both the inner surface of the lower portion of the housing 202 and the lower surface of the securing ring 226.

T-o provide means for driving or impelling air through the passageway or space 230, the upper end of the armature 210, which is recessed to reduce its mass, is provided with a vane or plunger 236 that is interposed between a ange 210a on the armature and a collar 23S. A conical armature return spring 240 is interposed between the collar 238 and the upper surface of the ring 226 and normally holds the upper end of the .armature 210 in engagement with a resilient element 242. This element is carried on the cover 220 and is used -to cushion the return movement of the :armature 210. The armature 210, the blade 212, and the spring 240 can be removed through the open top of the housing 202 by removing the closure 220. The winding means 206 and .the spacers 234 can be removed by removing the locking means 226.

When the tool 200 is operated and the winding 206 is energized, the armature 210 and the vane or air impelling element 230 move downwardly against the force of the compression spring 240. During this movement, the element 236 impels or forces air drawn into the interior of the upper portion of the housing 202 through a plurality of intake or inlet ports or openings downwardly through the annular space yor passageway 230 and discharges this air through .the slots 228 and the openings 232. Since the slots 228 are very smal-l and can be closed, if desired, by a nonconductive material, the bulk of the air is discharged through the openings 232 and passes substantially completely around and along the entire length of the outer surface of the winding 206. When the winding 206 is de-energized, the return spring 240 restores the armature 210 and the driver blade 212 to the normal position shown in FIG. 4. During this return movement, the suction created by the upward movement of the plunger or vane 236 draws air int-o the space 230 through the opening 232. This ow of air during the oppositely directed movements of the armature 210 incident to each oper-ation of the tool 200 removes the heat generated by .fthe energization of the Winding 206 and maintains the operating temperature of the tool 200 within the desired temperature range.

In certain applications, such as those in which the components for controlling the energiza-tion of the winding 206 are to be carried in or on the handle 204, it is desirable to insure that the heat from the winding means 206 that is not removed by the cooling means described above is not transmitted to the handle 204. Accordingly, a layer or body of heat insulating material 246 (FIG. 4) is interposed between the separate handle 204 andthe housing 202. This heat insulating material can be applied to either of the members 202 or 204 or can be formed as a gasket that is interposed between these two components during their assembly. The use of the body 246 of heat insulating material retards the transmission of heat generated by .the winding 206 to the handle 204 and protects any electronic componen-ts carried therein `from the adverse effects of excessive temperature rises.

As indicated above, the nosepiece assembly 216 and the magazine assembly 210 are pivotally mounted relative to the remainder of the tacker 200 to provide means for maintaining the nosepiece assembly 216 in engagement with the workpiece when the tool 200 is operated. The rear end of the magazine assembly 218 includes a generally U-shaped element 250 that is pivotally connected to the rear end 204e of the handle 204 by a hinge or pivot assembly indicated generally at 252. To provide means for movably connecting the nosepiece assembly 216 with the housing. 202, the assembly 216 includesa nosepiece element 254 defining the drive track 211i and having a threaded boss at its upper end on which is threadedly mounted a flanged collar 256. This collar is disposed Within an opening 25S inthe lower wall of the element 222. A compression spring 25d disposed within a circular opening 262 in the boss portion of the nosepiece element 254 engages a lower surface of the member 222 within the opening 25S to normally bias the nosepiece assembly 216 and the magazine assembly 218 to` the position illustrated in FIG. 4. ln this position, the lip or flange on 'the collar 25o engages the upper edge of an annular plate 264i that is secured to the member 222 at the lower end of the housing 262.

When the tool Ztl@ is to be operated, the nosepiece assembly 216 is placed against the workpiece, and the handle 204 and the housing 2(92 are moved downwardly against the action of the compression spring 260 to the position shown in FlG. 6 which is determined by the engagement of the upper end of the collar 25o and the boss portion of the nosepiece element 254 with the lower Wall of the member 222 within the opening 258. When the tool 200 is then operated by energizing the winding 2%, the recoil produced by the force required to place the armature 210 in motion and which results from the oppositely directed components of force tending to move the armature 210 downwardly and the winding 206 in the housing 262 upwardly is absorbed by permitting the housing 202 and the handle 29d to move upwardly in a clockwise direction about the pivotal axis of the assembly 252. During this movement, the compression spring 260 holds the lower end of the nosepiece assembly 216 in engagement with the workpiece and insures that the fastener supplied by the magazine 218 is properly driven. The drive track 214 and the blade 212 are so proportioned that the" movement of the nosepiece assembly 216 does not cause the blade 212 to bind in the drive track 214-.

The movement of the nosepiece assembly 216 and the magazine assembly 218 relative to the remainder of the tool 200 can be used to actuate a safety switch means to insure that the nosepiece assembly 216 is in engagement with the workpiece prior to the operation of the tool 259i?. More specifically, a safety switch 270 is secured to the member 222 with a switch actuator element 272 disposed immediately above an upper surface of the adjacent portion of the magazine assembly 21d. When the tool Ztl@ is placed against the workpiece and depressed so that the magazine assembly 218 and the nosepiece assembly 216 pivot in a clockwise direction about the hinge assembly 252, the actuator element 272 is engaged and actuated to operate the switch 276.

Although the present invention has been described with reference to several embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A fastener driving tool comprising a housing structure defining a generally cylindrical and vertically extending chamber communicating with a drive track at its lower end, winding means having an axial opening and an upwardly projecting locating structure at its upper end, said winding means being disposed in the chamber with the axial opening in alignment with the drive track, spider means having a central opening in which the upwardly projecting locating structure on the winding means is received, detachable fastener means engaging the wall of the chamber and bearing against an outer portion of the spider means to secure the spider means and the winding means in a desired position within the chamber, the engagement of the locating structure by the spider means holding the winding means in an upright position within the chamber spaced from the inner wall of the housing to provide a generally annular air space surrounding the winding means, said housing structure having at least one opening communicating with the annular air space adjacent the winding means, and fastener driving means slidably mounted in the drive track and including armature means slidably mounted in the axial opening and normally projecting above the upper end of the winding means into an upper portion of the chamber above the Winding means and the spider means.

2. rl`he fastener driving tool set forth in claim 1 in which the armature means is generally cylindrical and of a diameter substantially less than the diameter of the upper portion of the chamber in which it is normally disposed, said armature means having a projecting portion adjacent its upper end, and a generally conical resilient spring means disposed in the upper end of the chamber having a smaller diameter portion engaging the projecting portion on the armature means and a larger diameter portion supported adjacent the upper end of the Winding means.

3. The fastener driving tool set forth in claim 2 in which the housing structure includes a top opening at the upper end of the upper portion of the chamber having a size to permit the passage of the spring means, spider means, and winding means therethrough; a closure member detachably secured to the housing structure to normally close said top opening; said closure member providing a stop for arresting movement of the armature means by the spring means, said closure member being removable to permit the removal of the spring means and the fastener driving means through the top opening and the fastener means being thereafter removable to permit the spider means and the winding means to be removed from the housing structure through the top opening.

4. The fastener driving tool set forth in claim 1 in "which the spider means comprises a generally circular plate having the central opening for receiving the upwardly projecting locating structure, the outer diameter of the plate being no greater than the diameter of the chamber, and in which the detachable fastener means includes a resilient and generally C-shaped member, the inner wall of the housing structure having a recess in which the C-shaped member is received in a position bearing against the outer portion of the plate.

5. A fastener driving tool comprising a housing structure defining a generally cylindrical and vertically extending chamber communicating with a drive track at its lower end, said housing structure also including structure defining a generally circular opening adjacent the lower end of the chamber, winding means having generally concentric upper and lower bossed portions and an axial opening passing therethrough, said winding means being disposed in the chamber with the axial opening in alignment with the drive track and with the lower bossed portion disposed in the circular opening, spider means having a central opening in which the upper bossed portion of the winding means is received, detachable fastener means engaging the wall of the chamber and bearing against an outer portion of the spider means to secure the spider means and the winding in a desired position within the chamber, the engagement of the upper and lower bossed portions by the spider means and the structure defining the opening serving to hold the winding means in an upright position within the chamber spaced from the inner wall of the housing structure to provide a generally annular air space surrounding the winding means, said housing structure having at least one opening communicating with the annular air space adjacent the winding means, and fastener driving means slidably mounted in the drive track and including armature means slidably mounted in the axial opening and normally projecting above the upper end of the winding means into an upper portion i l i 2 of the chamber above the Winding means and the spider References Cited by the Examiner means.

6. The fastener driving tool set forth in claim l in UNITED STATES PATENTS which the spider means includes at least one other open- 757,991 4/04 Christmas 310-16 X ing disposed between the cent1-al opening and the outer 5 864,259 8/07 Bathbun 310-16 X portion of the spider means for placing the annular air 1,128,036 2/ 15 Paulero 310-16 X space in communication with the upper portion of the 1,723,607 8/ 29 DOmHqUSZ 310-*16 X chamber disposed above the Winding means, and in which 1,837,197 12/31 Berman 310-16 X is provided a generally circular resilient pumping element 2,572,012 10/51 CUTIS. carried by the armature means at the end remote from 10 2,967,302 1/61 LOVGCSS. the Winding means and disposed in the upper portion of 3,017,635 1/62 KOeIlDSCke. the chamber, said pumping element being moved toward FOREIGN PATENTS and away from the winding means as the armature means is operated to move air through the annular air space to 216983 Y 8/61 Ausma' cool the tool. 15 GRANVILLE Y. CUSTER, IR., Primary Examiner.

Claims (1)

1. A FASTENER DRIVING TOOL COMPRISING A HOUSING STRUCTURE DEFINING A GENERALLY CYLINDRICAL AND VERTICALLY EXTENDIONG CHAMBER COMMUNICATING WITH A DRIVE TRACK AT ITS LOWER END, WINDING MEANS HAVING AN AXIAL OPENING AND AN UPWARDLY PROJECTING LOCATING STRUCTURE AT ITS UPPER END, SAID WINDING MEANS BEING DISPOSED IN THE CHAMBER WITH THE AXIAL OPENING IN ALIGNMENT WITH THE DRIVE TRACK, SPIDER MEANS HAVING A CENTRAL OPENING IN WHICH THE UPWARDLY PROJECTING LOCATING STRUCTURE ON THE WINDING MEANS IS RECEIVED, DETACHABLE FASTENER MEANSF ENGAGING THE WALL OF THE CHAMBER AND BEARING AGAINST AN OUTER PORTION OF THE SPIDER MEANS TO SECURE THE SPIDER MEANS AND THE WINDING MEANS IN A DESIRED POSITION WITHIN THE CHAMBER, THE ENGAGEMENT OF THE LOCATING STRUCTURE BY THE SPIDER MEANS HOLDING THE WINDING MEANS IN AN UPRIGHT POSITION WITHIN THE CHAMBER SPACED FROM THE INNER WALL OF THE HOUSING TO PROVIDE A GENERALLY ANNULAR AIR SPACE SURROUNDING THE WINDING MEANS, SAID HOUSING STRUCTURE HAVING AT LEAST ONE OPENING COMMUNICATING WITH THE ANNULAR AIR SPACE AD-

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