US3643918A

US3643918A - Nail-extracting device

Info

Publication number: US3643918A
Application number: US885042A
Authority: US
Inventors: Rollo G Ellis
Original assignee: ROLLO G DITTY
Current assignee: ROLLO G DITTY
Priority date: 1969-12-15
Filing date: 1969-12-15
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22

Abstract

A device operable to remove nails, spikes or the like from any material within which said nails or the like may be driven, comprising a pneumatically operated impact member drivingly engaging a pair of pivotally mounted jaws and adapted to reciprocate the jaws between a first position in which the jaws are pivoted relative to one another to engage the head of the nail and a second position in which the jaws withdraw the nail from the material.

Description

United States Patent 51 Feb. 22, 1972 sf'i 2,706,103 4/1955 Stambaugh ..254/ l 9 2,735,649 2/1956 Swallert 2,797,889 7/1957 Talboys 2,639,887 5/1953 Henry ..254/l9 Primary Examiner-Othell M. Simpson Attorney-Hauke, Gifiord and Patalidis [57] ABSTRACT A device operable to remove nails, spikes or the like from any material within which said nails or the like may be driven, comprising a pneumatically operated impact member drivingly engaging a pair of pivotally mounted jaws and adapted to reciprocate the jaws between a first position in which the jaws are pivoted relative to one another to engage the head of the nail and a second position in which the jaws withdraw the nail from the material.

15 Claims, 9 Drawing Figures NAIL-EXTRACTING DEVICE BACKGROUND OF THE INVENTION l Field of the Invention The present invention relates to improvements in nail-extracting devices and is particularly applicable to those of the type which are pneumatically operated.

2. Description of the Prior Art Heretofore various mechanical and power-operated types of nail-extracting devices have been devised and have included as their source of power electrical motors or hydraulic or pneumatic power means.

Nail-extracting devices having electric motors as a source of power are characterized by several disadvantages such as the weight of the electric motor and the expense of their manufacture as they require special gearing in order to actuate the nail-extracting mechanism. Hydraulic and pneumatic type power means which have been previously used to actuate nailextracting mechanisms have been very complicated in their manufacture requiring numerous cooperating parts and have been generally designed for use with heavy-duty work such as removing spikes from railroad ties and the like and thus are very heavy and difficult to manipulate and are not adaptable for use by a single individual where a relatively lightweight nail-extracting device is desired and necessary.

Further many of the previously developed nail-extracting devices have not included means for effectively driving the nail-engaging jaws of the device into the material surrounding the nailhead and have been intended for use only in withdrawing spikes in which the head is projected above the surface of the material from which they are to be extracted.

Lightweight, pneumatically operated devices adapted to have the nail-engaging mechanism driven into the material surrounding the nailhead so as to extract the nail have been previously developed, and, some of these to a great extent, overcome many of the disadvantages of the heretofore-mentioned devices. However, these devices require numerous parts including complicated hydraulic or pneumatic systems, and due to the complexity of their construction are generally expensive in their manufacture.

It is therefore desirable to provide a device operable to remove nails, spikes or the like from the material from which said nails or spikes are embedded. Such a device should be constructed in a lightweight, simple, and inexpensive fashion. Such a simple and lightweight device would be adaptable for a variety of uses, particularly for the unpackaging of materials boxed in wooden or similar containers wherein it is necessary to open the container to remove the materials therefrom. The

nail-extracting device of the present invention would greatly minimize the amount of unpackaging time heretofore required by providing the unpacker with a device which is lightweight, simple in operation and which quickly engages the nails to withdraw them from the material in which they are embedded.

SUMMARY OF THE PRESENT INVENTION The present invention which will be subsequently described in greater detail comprises a nail-extracting device including a housing having a pair of handles to permit the user thereof to easily manipulate the device. The housing has a generally cylindrically shaped power section with a tubular extension of a rectangular cross section extending from one end thereof. A piston reciprocally mounted within the cylindrical power section is responsive to fluid pressure selectively communicated to the opposite sides of the piston to drive the same to and away from the tubular extension. The wall of the piston facing the tubular extension has an impact member secured thereto which extends from the power section into the tubular extension where it is adapted to drivingly engage a pair of pivotally mounted nail-engaging jaws. The impact member and the jaws are so arranged that movement of the piston toward the tubular extension drives the nail-engaging jaws toward an outer opening inthe tubular extension into a clasping engagement with the head of an embedded nail. Movement of the piston away from the tubular extension withdraws the jaws into the tubular extension and permits withdrawal of the nail from the material in which it is embedded. Valving means carried within the power section are adapted to be manipulated by the operator of the device to selectively direct fluid pressure to the opposite sides of the piston to commence movement of the piston in the desired direction.

The simple construction of the present invention represents an improvement over previously used nail-extracting devices in that it is extremely simple and relatively inexpensive to construct and maintain.

It is therefore an object of the present invention to provide an improved nail-extracting device which obviates the shortcomings and inaccuracies of previously used nail-extracting devices.

Other objects and advantages of the present invention will become apparent to those skilled in the art when the accompanying description of one example of the best mode contemplated of practicing the invention is read in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS The description makes reference to the accompanying drawings wherein like reference ntimerals refer to like parts and in which: 1

FIG. 1 is a perspective view of alnail-extracting device incorporating the present invention; 7

FIG. 2 is an exploded perspective view of the nail-extracting device illustrated in FIG. I;

FIG. 3 is a longitudinal sectional view of the nail-extracting device illustrated in FIG. I;

FIG. 4 is a transverse sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary view showing the nail-engaging jaws at the commencement of penetration into a wooden member;

FIG. 6 is an enlarged fragmentary view similar to FIG. 5 illustrating the nail-engaging jaws at the commencement of the extracting operation;

FIG. 7 is an enlarged fragmentary view similar to FIGS. 5 and 6 illustrating the nail-engaging jaws after the nail has been removed from the wooden member;

FIG. 8 is an enlarged fragmentary partially sectional view of the valve mechanism illustrated in FIG. 3; and

FIG. 9 is a transverse sectional view taken generally along line 99 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and particularly FIGS. I, 2 and 3, there is illustrated a pneumatically operated nail-extracting device 10 which is adapted to engage the head of a nail II to withdraw the same from a material 13 in which the nail I1 is embedded.

Although the device 10 is illustrated as being pneumatically operated, it is to be understood that the invention is not restricted to such operation, and that other fluid mediums such as hydraulic fluids may be utilized to provide the motor force for actuating the device 10.

The nail-extracting device 10 comprises a housing 12 having a power section 14 and a tubular extension 16. The housing 14 has a pair of diametrically

opposed handles

18 and 20 integrally formed therewith to provide the user of the device with a means for supporting and manipulating the nail-extracting device 10. The power section 14 may be formed from any suitable lightweight material such as aluminum or steel.

The power section 14 is provided with a longitudinal bore 22 in which is mounted a piston member 24 adapted to slidably engage the inner periphery of the bore 22 and reciprocate back and forth therein in response to fluid pressure communicated to the

opposite sidewalls

21 and 23 of piston member 24. The piston member 24 divides the bore 22 into two

pressure chambers

26 and 28 respectively above and below the piston member 24 as viewed in FIG. 3. O-ring type seals 29 placed about the outer periphery of piston member 24 slidably engage the surface of the bore 22 to prevent fluid communication between the

pressure chambers

26 and 28. By selectively communicating fluid to either of the

pressure chambers

26 or 28, the piston will be reciprocated within the bore 22 in a manner to be described in greater detail hereinafter.

The tubular extension 16 is of a generally rectangular shape having an enlarged cylindrical end section 32 received within the open end of the longitudinal bore 22 wherein an annular flange 33 radially extending from the enlarged end 32 abuts the exterior surface of the housing 12. The enlarged end 32 of the tubular extension 16 is securely retained to the power section 14 by means of a retainer ring 34 (FIGS. 3 and 9) which has a recess 35 engaging the outer periphery of the flange 33. Bolts 36 extend through a plurality of annularly spaced apertures 37 to engage axially aligned threaded bores 41 within the housing 12.

The tubular extension 16 consists of a base 38 formed integrally with the enlarged end 32, and a cover plate 40 which is joined to the base 38 by a plurality of screws indicated at 42. The cover plate 40 and the base 38 form a longitudinal guide bore 39 of a generally rectangular cross section in which a pair of nail-

engaging jaws

44 and 46 are mounted for reciprocal movement in a manner to be explained in greater detail hereinafter. The tubular extension guide bore 39 has an opening 47 adjacent the opposite end 49. of the tubular extension 16. The end 49 is adapted to abut the surface 51 of the material 13 in which the nail 11 is embedded. r

Each of the

jaws

44 and 46 have teeth 48 at their lower extremity and impact surfaces 50 at their upper extremities. The midsection of each of the

jaws

44 and 46 has a boss 52 in which a pintle bearing 54 is disposed to join

thejaws

44 and 46 for pivotal movement about the axis of the pintle bearing 54. A lubricant-saturated medium 55 disposed with a transverse bore 57 within the pintle bearing 54 provides proper lubrication thereof. A compression-type spring 56 carried on the inner

opposing faces

58 and 60 respectively of the

jaws

44 and 46 exerts an outwardly directed force on the

jaws

44 and 46 to pivot the jaws about the pintle bearing 54 and spread the teeth 48 apart.

The pivotally attached

jaws

44 and 46 form between their upper extremities a truncated shaped recess 62 having opposing

inner surfaces

64 and 66 which are inclined with respect to the axis of the tubular extension guide bore 39.

The

jaws

44 and 46 are adapted for reciprocal movement within the tubular extension guide bore 39 toward and away from the opening 47 by means of an impact member 70 which connects the

jaws

44 and 46 to the piston member 24. The impact member 70 is an elongated cylindrically shaped rod slidably mounted in an axial bore 71 extending through the enlarged end 32. One end 73 of the impact member 70 is disposed within a bore 72 which extends through the piston member 24. A step 74 formed on the outer periphery of the impact member 70 abuts the wall 23 of the piston member 24 to prevent inward axial movement of the impact member 70 while a nut 76 threadedly engaged to the end 73 of the impact member 70 securely retains the same to the piston member 24. Nut 76 is so sized as to be fitted within a recess 78 formed within a cylindrical shape axial extension 80 of the piston member 24, the purpose of which will be explained in greater detail hereinafter.

Suitable sealing means provided in a recess 75 within the bore 71 prevents fluid leakage from the pressure chamber 28 into the tubular extension guide bore 39.

The other end of the impact member 70 has an enlarged portion 86 of a generally rectangular shaped and so sized that the peripheral surface thereof slidably engages the rectangu- Iarly'shaped guide bore 39. An impact surface 88 formed on the bottom of the enlarged portion 86 is adapted to engage the impact surfaces 50 formed on the upper extremities of the

aws

44 and 46 to provide the connecting means for driving the jaws toward the opening 47 as the piston member 24 traverses from top to bottom, as viewed in FIG. 3, in response to fluid pressure being selectively directed to the pressure chamber 26.

A truncated flange 89 extends from the impact surface 88 and is disposed within the truncated recess 62. Flange 89 has a pair of opposing

surfaces

90 and 91 which respectively engage the opposing

surfaces

64 and 66 of the jaws during the upward stroke of the piston member 24 to thereby provide a second driving connection between the jaws and the impact member 70 as will be explained in greater detail hereinafter.

The actuating fluid medium may take the form of pressurized air and is communicated to the nail-extracting device 10 by ahose 92 having suitable nozzle coupling 93 which readily engage an inlet port 93 of the device 10. Pressurized air entering the device 10 is directed to a valving mechanism generally indicated at 94 by a drilled passageway 96. The valving mechanism 94 is adapted to selectively direct fluid pressure to the passageway 97 or passageway 99 which in turn are respectively connected to the

pressure chambers

26 and 28 on opposite sides of the piston member 24. When fluid is directed to the pressure chamber 28, the piston member 24 is moved by the force of the fluid pressure acting on wall 23 in a direction away from the opening 47, that is, in an upwardly direction as viewed in FIG. 3. When fluid is directed to the pressure chamber 26, the piston member 24 is moved toward the opening 47 by the force of the fluid acting against the piston wall 21. That is, in a downwardly direction, as viewed in FIG. 3. Since the

jaws

44 and 46 are drivingly connected to the piston member 24 by means of the impact members 70, the

jaws

44 and 46 will reciprocate in the same manner as the piston member 24. An upper wall 100 of the bore 22 has a cylindrically shaped seat 98 formed therein, the diameter which exceeds the diameter of the piston member axial extension 80 by a predetermined amount. When fluid is directed into the pressure chamber 28 by means of the valving mechanism 94, the pressure of the fluid therein acts against the piston member 24 to drive the same upwardly until the piston member wall 21 abuts the upper wall 100 of the bore 22. Since the pressure of the fluid acting against the piston member 24 exerts a considerable force thereon, suitable means must be provided at the upper end of the bore 22 to cushion the force of impact of the piston member 24 as the same reaches the end of its travel. Such a cushion is provided by the engagement of the axial extension 80 and the seat 98. As the axial extension 80 engages the seat 98, the fluid trapped therein acts as a cushion to absorb the shock of the piston member as its upward movement is stopped. By properly sizing the diameter of the seat 98 and the diameter of the axial extension 80, a proper clearance between the two engaging parts will permit a proper rate of fluid leakage from within the seat 98 so as to cushion the movement of the piston member 24 at a rate sufficient to stop the piston member 24 without causing damage to the upper wall 100 of the bore 22 or the piston member 24.

When the piston member 24 is in a position furthermost away from the opening 47, the axial extension 80 is engaged with the seat 98. When it is desired to shift the piston member 24 downwardly to move the

jaws

44 and 46 towards the opening 47 and into engagement with the nail 11, pressure fluid is selectively directed by the valving mechanism 94 into the pressure chamber 26. A recess 101 formed in a portion of the upper wall 100 communicates fluid from the passageway 97 into the pressure chamber 26 and exerts a force against the piston member wall 21 to move the same in a downwardly direction. As the piston member 24 is initially moved downwardly out from the seat 98, the movement of the axial extension 80 therefrom will be resisted by a suction effect created within the seat 98, thus permitting a pressure buildup within the pressure chamber 26 behind the piston member 24 until the axial extension 80 disengagcs the seat 98. At the moment of disengagement the piston member 24 will accelerate in a downwardly direction to drive the

jaws

44 and 46 toward the opening 47 of the tubular extension member 16 to drive the teeth 48 into the surface 51 of the material 13.

Referring now to FIG. 8 for a detailed description of the valving mechanism 94 and the manner in which fluid is selectively directed to the opposite side of the piston member 24. The valving mechanism 94 comprises a valve sleeve 102 fixedly positioned within a longitudinal tapered bore 104 extending through the handle 18. The sleeve 102 is provided with a plurality of axially spaced

ports

106, 108 and 110, each of which respectively engages

annular recesses

112, 114 and 116 extending around the outer periphery of the sleeve 102. The

annular recesses

112, 114 and 116 are respectively in fluid communication with

passageways

97, 96 and 100. Each of the recesses 112-116 are axially separated by a plurality of 0- rings 118 suitably disposed in recesses 119 along the outer periphery of the sleeve 102 and adapted to engage the inner periphery of the bore 104 to prevent fluid communication between the several annular recesses. The

ports

106, 108 and 110 communicate with a longitudinal bore 120 which extends through the sleeve 102 and in which a spool 121 is reciprocally mounted. Spool 121 has a pair of radially extending lands 122 and 124, each of which is provided with an O-ring 123 adapted to engage the inner peripheral surface of the bore 120 to prevent fluid communication between the opposite sides of the lands 122 and 124.

As viewed in FIG. 8, the right end of the spool 120 has an enlarged portion which forms a trigger 126 in which the user of the device presses and depresses to selectively communicate pressure fluid to either of the

pressure chambers

26 or 28 as will be explained in greater detail hereinafter. The opposite end of the spool 121 has a stop plate 130 attached thereto by means of a threaded bolt 132. A portion of the inner surface of the stop plate 130 abuts the outer left end of the spool sleeve 102 to limit the rightwardly axial movement of the spool 121 which in turn is biased in an rightwardly direction by a spring 134 disposed between the right end of the sleeve 102 and a shoulder 136 formed on the trigger 126. The inner surface of a stop plate 130 has a plurality of annularly spaced grooves 138 which are adapted to connect the bore 120 to the bore 104 so as to vent pressurized air from the pressure chamber 26 as will be further described hereinafter.

During normal operation of the valve mechanism 94, the spring 134 biases the spool 121 such that fluid communication between the port 108 and the port 110 is maintained so as to continuously direct fluid pressure from the hose 92 to the pressure chamber 28 and thereby bias the piston member 24 against the upper wall 100 of the bore 22.

To commence operation of the device 10 to drive the piston member 24 in a downwardly direction and thus drive the

jaws

44 and 46 into the surface of the material 13, the operator of the device 10 presses the trigger 128 inwardly. The inward movement of the trigger 128 displaces the spool 121 until the land 124 closes fluid communication between the port 108 and the port 110 while the land 122 opens communication between the port 108 and the port 106, thereby directing fluid pressure from the hose 92 to the pressure chamber 26. The pressure fluid communicated to the pressure chamber 26 exerts a force against the piston member wall 21 to urge the same in a downwardly direction toward the openings 47.

As hereinbefore described, the downward movement of the piston member 24 is delayed until pressure is built up behind the piston member 24 so as to exert a force of sufficient magnitude to overcome the suction which is developed between the axial extension 80 and the seat 98. When a predetermined pressure has been reached as for example 80 p.s.i., the piston member 24 will be shifted downwardly under the force of the pressure acting thereon, to drive the

jaws

44 and 46 toward the material 13. The air within the pressure chamber 28 is forced therefrom by the downward movement of the piston member 24 into the axial passageway 99 and is exhausted externally of the device 10 via the valving mechanism 94. When the

jaws

44 and 46 have engaged the nail, in a manner to be described hereinafter. the operator of the device releases the trigger 128 which in turn closes communication between the port 108 and the port 106, while at the same time redirecting fluid pressure from the port 108 to the port which in turn directs fluid pressure to the pressure chamber 28 to thereby exert a force against the wall 23 of the piston member 24 to urge the same in an upwardly direction. The upward movement of the piston member 24 forces the fluid within the pressure chamber 26 into the passageway 97 whereupon it is exhausted from the device 10 through the spool bore and the annular recesses 138. The piston member 24 returns to the upper end of the bore 22 wherein the axial extension 80 engages the seat 98 in the same manner as hereinbefore described.

Refer now to FIGS. 5, 6 and 7 for detailed description of the manner in which the device 10 is operative to remove the nail 11 from the wooden medium 13. In operation the user of the device 10 presses the trigger 126 to commence the downward movement of the piston member 24 whereupon the impact surface 88 of the enlarged portion 86 abuts the impact surfaces 50 of the

jaws

44 and 46 to drive the same in the direction of the wooden member 13, whereby the teeth 48 are driven into the surface 51 of the wooden member 13 as illustrated in FIG. 5.

In order to insure that the teeth 48 engage the underside of the head of the nail 11 in a clamping engagement to produce a proper withdrawal of the nail from the wooden member 13, the tubular extension guide bore 39 has an inclined surface 140 (FIG. 7) proximate the opening 47. The outer walls of each

jaw

44 and 46 at the lower extremities thereof are engaged by the cam surface 140 to cam the teeth 48 inwardly towards the nail 11 at the same time the teeth are penetrating the wooden member 13, thus insuring the teeth 48 engage the underside of the head of the nail 11.

As an alternative to the cam surface 140, the teeth 48 may have an inclined lower portion 146 of such design that the resultant force acting against the teeth 48 when the same enter the upper surface 51 of the wooden medium 13, will be to direct the teeth 48 inwardly under the head of the nail 1 1.

In order to insure that the head of the nail II and the teeth 48 of the

jaws

44 and 48 are properly aligned so as to clampingly engage the teeth 48 with the nail 11 upon actuation of the device 10 a portion of the cover and base are pn vided with a slot which extends from the opening 47 upwardly along one side of the tubular extension 16 and is indicated by the numeral 150. As can be seen in the perspective view of FIG. 1, the device 10 may be visually aligned by the user to insure proper operation thereof once the device 10 is actuated.

After the teeth 48 of the jaws have engaged the underside of the head of the nail 11, the operator of the device 10 depresses the trigger 126 and thereby directs fluid pressure into the pressure chamber 28 to exert a force against the piston member wall 23 so that the same is displaced in an upward direction away from the openings 47 as hereinbefore described. As the piston member 24 travels in an upward direction, the opposing

surfaces

90 and 91 of a truncated flange 89 respectively engage the

inclined surfaces

64 and 66 on the inner'walls of

jaws

44 and 46 and thereby exert an upwardly directed force against the jaws to pull them away from the wooden member 13. Simultaneously with the upward directed force, the engaging inclined surface exerts an outwardly directed force against the upper extremities of the

jaws

44 and 46. Such an outwardly directed force tends to spread the upper extremities of the

jaws

44 and 46 thereby tending to maintain the teeth 48 in a clamping engagement about the head of the nail 11 while the nail 11 is being extracted from the wooden member 13. As the piston member 24 travels along the bore 22 to the inner end of the power section 14, the nail is withdrawn from the wooden member 13. The lower surface 47 of the device 10 is in abutment with the surface 51 of the wooden member 13 whereby the force of removing the nail is transferred back to the wooden member, and the user need exert only enough force and control upon the device 10 to maintain it in an upright position with respect to the wooden member 13.

FIG. 7 illustrates the device 10 as the nail is withdrawn from the wooden member 13. After the nail 11 is withdrawn from the member 13 the force of the spring 56 acting against the lower extremities of the jaws tends to separate them and release the nails from between the teeth 48, while the piston member 24 abuts the wall 100 in the manner hereinbefore described.

In order to minimize the weight in the overall assembly of the nail-extracting device 10, the components may be made from a lightweight material such as aluminum or aluminum alloys. Such material is suitable for forming the piston member and the housing 12. However those components which sustain impact and hard usage, such as the impact member 70, the

jaws

44 and 46 and, particularly, the teeth of the

jaws

44 and 46 should be formed from a suitable material such as tempered steel, all of which is well known in the art of metallurgy.

It can thus be seen that the present invention has provided a new extracting device which is extremely simple in construction, which is capable of being made of relatively lightweight materials and so designed that the same can be maintained and repaired in a simple and less expensive manner as compared to other previously mentioned extracting devices capable of performing similar functions.

Having thus described the invention is as follows.

Iclaim:

l. A nail-extracting device comprising a housing, an impact member reciprocably mounted in said housing, means for selectively reciprocating said impact member, a pair of pivotally mounted nail-engaging jaws reciprocably driven by said impact member, said impact member being operable to drive said jaws into a material containing a nail and to withdraw said jaws from said material to withdraw said nail therefrom as said impact member reciprocates to and from said material, the lower extremity of said impact member being positioned between the upper extremities of said pivotally mounted jaws and having at least two jaw engaging surfaces, said impact member being adapted for limited movement independently of said jaws between first and second positions wherein after movement of said impact member to said first position one of said jaw-engaging surfaces engages said jaws to drive the lower extremities of said jaws into said material as said impact member moves towards said material, camming means disposed at the lower extremities of said jaws and cooperating with said housing for pivoting said jaws relative to one another to close the lower extremities thereof into a clamping engagement with said nail as said jaws are driven by said impact member into said material, and wherein after movement of said impact member to said second position, the other of said jaw-engaging surfaces of said impact member engages said jaws to urge the upper extremities of said jaws to separate thereby maintaining said lower extremities in said clamping engagement with said nail while simultaneously said other jaw-engaging surface drives said jaws away from said material as said impact member moves in a direction away from said material to effect withdrawal of said nail therefrom.

2. The nail-extracting device as defined in claim 1 wherein said impact member is a rod having an enlarged end, said other surface being disposed thereon and inclined with respect to the direction of reciprocal movement of said rod, said jaws having opposing inclined surfaces approximate their upper extremities at a point above the pivotal axis of said jaws, said opposing inclined surfaces being engaged by said rod-inclined surfaces to spread said upper extremities of said jaws.

3. in a nail-extracting device of claim 2 including a radially extending flange carried by said rod, the lower surface thereof engaged the upper extremities of said jaws to drive the same into engagement with said material.

resilient means comprises a compression spring disposed between the opposite inner walls of said jaws at a point below said axis of pivotal movement.

6. The nail-extracting device of claim 1 wherein said housing includes a tubular member having a material abutting end surface, said jaws being mounted in said tubular member for reciprocal movement in response to said impact member.

7. The nail-extracting device of claim 6 wherein a portion of the inner walls of said tubular member cooperates with a portion of the outer walls of said jaws to guide said jaws as the same travel within said tubular member.

8. The nail-extracting device of claim 7 wherein a pair of opposing inner walls of said tubular member are shaped complementary to the cooperating wall portions of said jaws such that said jaw portions slidably engage said opposing inner walls of said tubular member.

9. The nail-extracting device of claim 6 wherein said camming means comprises a cam surface disposed on said tubular member approximate said material-abutting surface, said cam surface being inclined with respect to the direction of movement of said jaws, said cam surface engaging the lower extremities of said jaws to urge said jaws into a clamping engagement with said nail.

10. The nail-extracting device of claim 6 including a longitudinal slot extending upwardly from said material-abutting surface and through a portion of said tubular wall to provide the user of said extracting device with a view of said jaws to permit proper axial alignment thereof with the nail to be withdrawn from said material.

11. The nail-extracting device of claim I wherein said means for selectively reciprocating said impact member comprises a piston reciprocally mounted in said housing, the opposite sides of said piston forming the walls of a pair of pressure chambers, one of said walls being connected to said impact member to drive said impact member toward and away from said material when said opposite piston sides are al ternately exposed to fluid pressure, and means for selectively communicating fluid pressure to said pressure chambers.

12. The nail-extracting device as defined in claim ll wherein said piston, impact member, and jaws reciprocate along a common axis.

13. The nail-extracting device of claim I I wherein the other of said piston walls has an axial extension having a selected cross-sectional dimension, said housing having a wall opposite said other piston sidewall and having a bore therein of a crosssectional dimension which exceeds said extensions dimension by a predetermined amount so as to control the rate of the fluid flow therebetween, said extension engaging said bore when said piston moves away from said material so as to create a pressure therein to cushion said last-mentioned movement, said engagement of said extension with said bore resisting movement of said piston towards said material until the fluid pressure in said pressure chamber is associated with the other of said walls exceeds a predetermined amount.

14. The nail-extracting device of claim 13 wherein said fluid pressure operated piston is pneumatically operated.

15. The nail-extracting device of claim 6 wherein said tubular member is carried at one end by said housing and has radially extending flange in abutment with said housing and including a retainer surrounding said tubular extension and engaging said flange to securely retain said tubular extension to said housing; and means fastening said retainer to said housmg.

UNITED STATES PATENT OFFICE Certificate R0110 G. Ellis A plication having been made by R0110 G. Ellis, the inventor named in the patent above identified, for the issuance of a certificate under the provisions of Title 35, Sectmn 256, of the United States Code. addmn the name of Allan V. Ditty as a joint 111- ventoig'and a showing and proof of facts satisfying the requirements of the said section Patent No. 3,643,918

having been submitted, it is this 4th day of July 1972, certified that the name of the said Allan V. Ditty is hereby added to the said patent as a joint inventor with the said R0110 G. Ellis.

F RED WV. SI-IERLING,

Associate Solicitor.

Patented February 22,

Claims

1. A nail-extracting device comprising a housing, an impact member reciprocably mounted in said housing, means for selectively reciprocating said impact member, a pair of pivotally mounted nail-engaging jaws reciprocably driven by said impact member, said impact member being operable to drive said jaws into a material containing a nail and to withdraw said jaws from said material to withdraw said nail therefrom as said impact member reciprocates to and from said material, the lower extremity of said impact member being positioned between the upper extremities of said pivotally mounted jaws and having at least two jaw engaging surfaces, said impact member being adapted for limited movement independently of said jaws between first and second positions wherein after movement of said impact member to said first position one of said jaw-eNgaging surfaces engages said jaws to drive the lower extremities of said jaws into said material as said impact member moves towards said material, camming means disposed at the lower extremities of said jaws and cooperating with said housing for pivoting said jaws relative to one another to close the lower extremities thereof into a clamping engagement with said nail as said jaws are driven by said impact member into said material, and wherein after movement of said impact member to said second position, the other of said jaw-engaging surfaces of said impact member engages said jaws to urge the upper extremities of said jaws to separate thereby maintaining said lower extremities in said clamping engagement with said nail while simultaneously said other jaw-engaging surface drives said jaws away from said material as said impact member moves in a direction away from said material to effect withdrawal of said nail therefrom.

4. The nail-extracting device of claim 2 including resilient means carried by said jaws for biasing the lower extremities apart.

5. In a nail-extracting device of claim 4 wherein said resilient means comprises a compression spring disposed between the opposite inner walls of said jaws at a point below said axis of pivotal movement.

11. The nail-extracting device of claim 1 wherein said means for selectively reciprocating said impact member comprises a piston reciprocally mounted in said housing, the opposite sides of said piston forming the walls of a pair of pressure chambers, one of said walls being connected to said impact member to drive said impact member toward and away from said material when said opposite piston sides are alternately exposed to fluid pressure, and means for selectively communicating fluid pressure to said pressure chambers.

12. The nail-extracting device as defined in claim 11 wherein saId piston, impact member, and jaws reciprocate along a common axis.

13. The nail-extracting device of claim 11 wherein the other of said piston walls has an axial extension having a selected cross-sectional dimension, said housing having a wall opposite said other piston sidewall and having a bore therein of a cross-sectional dimension which exceeds said extensions dimension by a predetermined amount so as to control the rate of the fluid flow therebetween, said extension engaging said bore when said piston moves away from said material so as to create a pressure therein to cushion said last-mentioned movement, said engagement of said extension with said bore resisting movement of said piston towards said material until the fluid pressure in said pressure chamber is associated with the other of said walls exceeds a predetermined amount.

15. The nail-extracting device of claim 6 wherein said tubular member is carried at one end by said housing and has radially extending flange in abutment with said housing and including a retainer surrounding said tubular extension and engaging said flange to securely retain said tubular extension to said housing; and means fastening said retainer to said housing.