GB2163083A

GB2163083A - Gun for driving fasteners

Info

Publication number: GB2163083A
Application number: GB08420615A
Authority: GB
Inventors: Kolyma Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-08-14
Filing date: 1984-08-14
Publication date: 1986-02-19
Also published as: GB8420615D0

Abstract

A gun for driving fasteners such as nails having a guide tube (3) for containing a fastener (N), the guide take being telescopically displaceable into a barrel (H<1>) against a flange (5) carried by a punch member (4) which drives back a hammer (8) against a spring (11) which is thus compressed. A trigger (10) blocks movement of the punch member (4) into a bore (8f) of the hammer member until displaced by a step (H11) in the barrel, upon movement of the tube, flange and hammer rearwardly against the spring 11, to fire the hammer against flange (5) carried by the punch member. In the non-operative mode the trigger 10 engages a stepped portion 4d' of the member 4 to prevent the end part 4e thereof from engaging the bore 8f. When the trigger 10 is displaced the recess 10d thereof becomes aligned with the portion 4d of the member 4 and the bore 8f to cause the mutual engagement of the part 4e and the bore 8f to fire the pin 4 in consequence of the release of the spring 11 tension. <IMAGE>

Description

SPECIFICATION Gun for driving fasteners This invention relates to a gun for driving fasteners, for instance to a carpenter's nail gun.

The guns according to the invention allow fasteners to be inserted therein and driven into a work piece by pressing the gun against the workpiece.

Carpentry is an old trade but its importance remains unchanged. There are still many wood elements fastened together by means of nails or similar pointed fasteners such as staples. In nailing, one usually holds the nail with the thumb and index finger of one's left hand and strikes the head of nail with a hammer in one's right hand. It is easy to do so for a skillful carpenter, but for a novice or beginner, it must be done carefully or his finger would be hit or injured by the hammer.

So a main object of this invention is to provide a gun which will strike a fastener, e.g. a nail into a workpiece, e.g. to hold the nail with fingers so as to eliminate the danger of injury by the hammer.

Accordingly, the present invention provides a gun for driving in fasteners comprising a barrel having a longitudinal bore, having at its distal end an opening receiving an open ended guide tube which guide tube has at its distal end an opening through which fasteners are to be driven and has a proximal end portion received in the barrel bore such that the guide tube is telescopically slideable into the barrel bore from the distal end thereof, an elongate punch member having a distal part received in and slideable in the guide tube from the proximal end thereof, a hammer member in a proximal portion of the barrel bore, proximally displaceable against a resilient biassing means, receiving means in the distal end of the hammer member-able to receive a proximal end portion of the punch member, a trigger member carried by the hammer member and having a safe position in which the trigger member blocks penetration of said punch membmer into said bore of the hammer member and a fire position in which said penetration is permitted, and means in said barrel bore for displacing said trigger member from the safe to the fire position upon movement of said hammer member to a predetermined extent against said resilient biassing means.

In a second aspect, the invention provides a carpenter's nail gun comprising a barrel with sections of different diameters, a guide tube in which a nail is placed, a flat disc, a fire pin installed between the guide tube and the flat disc and havings its end extending to the back of the flat disc, a spring fitted over the fire pin, a hammer, a slide block and a strong spring. After a nail is placed in the guide tube and the guide tube is pressed against the wood to be nailed with one hand holding the stock of the gun, the guide tube wil retreat in the barrel and push the flat disc, the hammer to compress the strong spring. When the slide block is pressed down by the internal flange of the smaller caliber section of the barrel, the compressed strong spring will be suddenly released and push the hammer and the fire pin to strike the nail into the wood.

The invention will be illustrated by the following description of a preferred embodiment with reference to the accompanying drawings in which: Figure 1 is a longitudinal sectional view of a carpenter's nail gun of this invention.

Figure 2 is a perspective view of selected components of the said nail gun.

Figure 3 is an enlarged sectional view of the punch member or firing pin and the hammer of said gun in the normal positon.

Figure 4 is a similar view but of said gun in the position ready for striking.

As shown in Figure 1, the body of a carpenter's nail gun of this invention comprises a tubular bar- rel H1 of three different caliber sections H10, H11, H12, or of two different diameter sections H10 and H12 linked by an annular curved ramp H11.

The gun also comprises a muzzle 2 with an opening 2a fixed to the front ordistal end of the barrel H1 by means of thread, a guide tube 3 with an opening 3a slidably fitted in the opening 2a, and having a thicker part 3a with outside diameter roughly equal to the large caliber section H10, and a long tubular section 3b with outside diameter roughly equal to that of the opening 2a, and a guide flange 3d with a cushion ring 3e fixed to the front end of the long tubular section 3b. The thicker part 3a joins the long tubular section 3b at a step 3c.

The stem 4a of the punch member of fire pin 4, as shown in Figure 2a, is fitted in the opening 3b' of the long tubular section 3b. A flange is formed around the punch member by flat disc 5 with a hole 5a in which the first thinner part 4b of the punch member 4 is fitted, and fixed with a spring lock washer 6 in the ring groove 4c of the fire pin 4. A coil spring 7 is fitted over the stem 4a between the large caliber section 3a and the flat disc 5, with one end against the flat disc 5 and the other against the end surface of the long tubular section 3b. The second thinner part 4b and the end part 4c of the fire pin 4 extend to the back of the flat disc 5.

A hammer 8 as shown in Figure 2b and Figure 3 is coaxially and slidably installed in the barrel H1 behind the flat disc 5. The hammer 8 consists of a recess 8b at the front end for accomodating the spring lock washer 6, a spring 4f fitted between the recess 8b and the lock washer 6 over the fire pin 4 with elastic force greated than that of the spring 7 to keep the distance between the flat disc 5 and the hammer head 8a, a hole Sc for accomodating the second thinner part 4d of the fire pin 4, a hammer head 8a with outside diameter roughly equal to the caliber H10 of the barrel H1, a ring groove 8d with a cross hole 8d vertical to the axis, a hammer body 8e with outside diameter roughly equal to the caliber H12, and a longitudinal hole 8f in the center from the wall of the cross hole 8d, and a protrusion 8g extending coaxially from the hammer body 8e. A slit ring spring 9 is fitted over the ring groove 8d, and a trigger member of slide block 10 is inserted in the cross hole Sd as shown in Figure 2c.

The cylindrical block 10 has a round end 10a, a flat end 10, a longitudinal flat surface 10c, and a hole 10d in the cylindrical block 10 at the center of the longitudinal flat surface 10c, in which the second thinner part 4d of of the fire pin 4 is fitted. As shown in Figure 3, when the the slide block 10 is inserted in the cross hole 8d of the hammer 8 with the longitudinal flat surface 10e facing downward, the flat end 10b of the slide block 10 is seated against the inside wall of the slit ring spring 9 fitted over the ring groove 8d, and the axis of the hole 10d is above that of hole Sc in the hammer 8, looked like two eccentric holes from the side.

When the end part 4e of the fire pin 4 goes through the hole Sc into the hole 10d, the second thinner part 4d of the fire pin 4 passes the hole Sc but because of being eccentric, the stepwise part 4d is blocked by the rim of hole 10d, the second thinner part 4d can not go into the hole 10.

A strong coil spring 11 has one end fitted over the protrusion Sg of the hammer 8, and the other end against the breech end H13 of the barrel H1.

The butt plate H20 is fixed to the but H2 by means. of a screw 12.

Before use, the elements of the nail gun are in such positions as shown in Figure 1 and Figure 3.

The stepwise part 3c of the guide tube 3 keeps in contact with the rear end of the muzzle 2. The end part 4e of the fire pin 4 is fitted in the hole 10d and the second thinner part 4d passes through the hole 8c. But the stepwise part 4d is stopped by the rim of hole 10d of the slide block 10. The round end 10a of the slide block 10 contacts the linner wall of the large caliber section H10 of the barrel H1. The head 8a of the hammer 8 keeps a distance with the flat disc5 and the coil spring 11 is in the free state.

To use the gun, a nail N is put in the guide tube 3b, and the rubber cushion 3eis put on the wood where the nail is to be struck in. The pressure of the hand holding the butt H2 causes the guide tube 3 to retreat in the barrel H1. When the rear end of thinner part 3a touches the flat disc 5, the spring 7 will contract in the opening 3a of the thinner part 3a. (At this time no effect is on the nail.) Then the guide tube 3 and the flat discS pushes the lock washer 6, the spring 4f and the recess of the hammer 8 and, with the stepwise part 4d', causes the slide block 10 to move to press the spring 11.

When the round end 10a of the slide block 10 reaches the small caliber section 11 as shown in Figure 4, the round end 10a is pressed down by the internal wall flange of the barrel H1, and the holes 10d and Sc become coaxial. At this moment, the guide tube 3 and the flat disc 5 suddenly loss in resistance, and the spring 11 is released and pushes the hammer 8 with its head-8a to strike the flat disc 5, the spring 4f and the fire pin 4 which, in turn, strikes-the nail N into the wood. At this time the end part 4e of the fire pin 4 is inserted in the hole 8f.

As soon asthe strike is completed, the spring 11 recovers its original shape and pushes the hammer 8 and the flat disc 5 to their original positions through the elastic force of the spring 4f. The guide tube 3 also restores its original position as the spring recovers its original shape.

From the above, it is clear that the nail gun of this invention can be operated by one hand without fear of injury to the fingers and, with a rubber cushion 3e, it is free from causing damage to the wood.

Claims

1. A gun for driving in fasteners comprising a barrel having a longitudinal bore, having at its distal end an opening receiving an open ended-guide tube which guide tube has at its distal end an opening through which fasteners are to be driven and has a proximal end portion received in the barrel bore such that the guide tube is telescopi cally slideable into the barrel bore from the distal end thereof, an elongate punch member having a distal part received in and slideable-in the guidetube from the proximal end thereof, a hammer member in a proximal portion of the barrel bore, proximally displaceable against a resilient biassing means, receiving means in the distal end ofthe hammer member able to receive a proximal end portion of the punch member, a trigger member carried by the hammer member and having a safe position in which the trigger member blocks penetration of said punch member into said bore of the hammer member and a fire position in which said penetration is permitted, and means in said barrel bore for displacing said trigger member from the safe to the fire position upon movement of said hammer member to a predetermined extent against said resilient biassing means.

2. A gun as claimed in claim 1 wherein the trigger member is slideable transversely of the barrel bore and is biassed to slide to the safe position and has a through bore therein parallel to the barrel bore, whereby inthe safe position the axis of the trigger member bore is out of line with the punch member so that proximal movement of the punch member into the receiving means of the hammer member is blocked and in the fire position the bore of the.trigger member is substantially aligned with the punch member allowing passage of the punch member therethrough to penetrate into the receiving means of the hammer member.

3. A gun as claimed in claim 2 wherein the trigger member slides in a transverse through bore in the hammer member,

4. A gun as claimed in claim 3 wherein the trigger member and the transverse through bore are shaped to prevent axial rotation of the trigger member.

5. As gun as claimed in claim 3 or claim 4 wherein the trigger member is biassed to the safe position by a split annular spring member surrounding the hammer member in the region of the transverse bore and covering one end of the transverse bore such that the trigger member is displaced to protrude through the other end of said transverse bore.

6. A gun as claimed in any one of claims 2.to 5 wherein the punch member comprises a rod hav ing cylindrical portion received eccentrically in the bore of the trigger member in the safe position and connected via a step to a larger diameter cy cylindrical portion which passes into the bore of the trigger member only in the fire position.

7. A gun as claimed in any preceding claim wherein the hammer member is slideable in the barrel bore against a spring.

8. A gun as claimed in claim 7 wherein the hammer member has a proximal cylindrical portion of reduced diameter and said spring is a compression coil spring received over the reduced diameter portion of the hammer and abutting against a proximal stop member in said barrel.

9. A gun as claimed in any preceding claim wherein in use the punch member is displaced proximally by pressing the guide tube against a workpiece and in turn moves the hammer member against said resilient biassing means until the trigger member is displaced in the fire position.

10. A gun as claimed in any preceding claim wherein the punch member has an abutment provided intermediate its ends.

11. A gun as claimed in claim 9 wherein use the guide tube is displaced proximally by pressing the gun against a workpiece to bear against said abutment and cause said punch member to be displaced proximally to in turn move the hammer member against said resilient biassing means until said trigger member is displaced to the fire position.

12. A gun as claimed in any preceding claim wherein the abutment of the punch member is a flange member fixed intermediate its ends and slideable in the barrel bore.

13. A gun as claimed in any one of claims 10 to 12 wherein the guide tube is biassed away from said abutment.

14. A gun as claimed in claim 9 or claim 10, wherein said abutment is biassed away from the distal end of the hammer member.

15. A gun as claimed in any preceding claim wherein the distal end of the guide tube is provided with a cushion member to protect a workpiece.

16. A gun for driving fasteners substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

17. A carpenter's nail gun characterized by comprising a stock, a barrel of different calibers, and, slidably fitted in the barrel, such elements as a guide tube having a front section wherein a nail is put, a flat disc, a fire pin installed between the guide tube and the flat disc and havings its end part extending to the back of the flat disc, a spring fitted over the fire pin, a hammer with a strong spring, and a slide block installed behind the flat disc so that when the gun is pushed forward with one hand, the guide tube with its front end against the wood to be nailed will retreat and push the flat disc and the hammer to compress and spring behind the hammer; and, after the slide block reaches the internal flange of the smaller caliber section and is pressed down thereby, the fire pin will be released suddenly and strike the nail in the guide tube into the wood with the hammer pushed by the strong spring.

18. A nail gun according to claim 17 wherein the guide tube consists of a thicker part, a long tubular part, and a protective cushion fixed to the front end of the long tubular part.

19. A nail gun according to claim 17 wherein the flat disc has a hole in the center.

20. A nail gun according to claim 17, wherein the fire pin consists of a stem with outside diameter roughly equal to the inside diameter of the long tubular part of the guide tube, a first thinner part with outside diameter roughly equal to the diameter of the hole of the fl t disc, a ring groove for lock washer, a second thinner part with outside diameter roughly equal to that of the hole in the head of the hammer, and an end part with diameter small thatn that of the second thinner part.

21. A nail gun according to claim 17 wherein the hammer consists of a head with a recess for the lock washer and a hole for the second thinner part of the fire pin, a ring groove with a cross hole, a hammer body with a hole made longitudinally from the cross hole wall, and a protrusion extending coaxially from the hammer body.

22. A nail gun according to claim 17 wherein the ring groove has a slit ring spring fitted over.

23. A nail gun according to claim 17 wherein the slide block has a round end, a flat end, a longitudinal cutaway flat surface, and a hole made in the center of the cylindrical body for the second thinner part of the fire pin.

24. A nail gun according to any one of claims 17, 21, 22 or 23 wherein the hole of the slide block and the hole of the hammer head become eccentric holes after the slide block is inserted in the cross hole of the hammer with its flat surface facing downward.

25. A nail gun according to any one of claims 17,21, 22, 23 or 24 wherein the end part of the fire pin goes through the hole of the hammer head and the hole of the slide block and to the rear of the slide block, and the second thinner part of the pin also goes through the hole of the hammer head but is stopped at its stepwise part by the protruding rim of the slide block hole in normal state.

26. A nail gun according to claim 17 wherein the strong spring has one end fitted over the protrusion of the hammer, and the other against the rear end of the barrel.