US2570914A

US2570914A - Nail puller

Info

Publication number: US2570914A
Application number: US11389A
Authority: US
Inventors: Clarence N Buck
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-02-27
Filing date: 1948-02-27
Publication date: 1951-10-09
Anticipated expiration: 1968-10-09

Description

C. N. BUCK NAIL PULLER Oct. 9, 1951 2 sheetsTsheet 1 Filed Feb. 27, 1948 oct. 9,1951 c, N, BUCK 2,570,914

' NAIL FULLER Filed Feb. 27, 1949 sheets-sheet 2 @9.7 .@5151 JQ-Q9 A .aarencejlfuC/.

Patented Oct. 9, 1951 YUNITED STATES ijiiit @FFICE 11 Claims. 1

The present invention relates to nail pullers and Certain improved constructions and arrangements of elements by which a nail is quickly withdrawn rectilinearly from its lodgment.

Nail pullers heretofore used have been of the hammer-lever construction in which a vert1cal shaft is pivoted to a horizontal shoe, and both the shoe and shaft are provided with jaw members to grip the nail when the shaft is tilted in the direction of the shoe. upon the shaft is used as a slide hammer to drive Athejaws into the wood on opposite sides of the nail before the jaws are levered to grip the nail. Thereafter the shaft is levered about the shoe to -pull the nail through an arc which bends the nail and renders it unt for further use.

Such nail pullers require long shafts so that the back stroke of the hammer will not displace the jaws fromvtheir proper position. On the other hand, a heavy hammer and a short stroke is eX- tremely tiring to an operator when a nail puller is to be used vfor any length of time. Not only this, but the conventional nail pullers require' a great deal of space around the nail to allow for leverage movement of the shaft and the direction of this leverage is limited because the shoe has to rest upon a substantial length of the board 'in' which the nail is driven, for obvious reasons. Furthermore, the slightest deviation from the plane of leverage movement causes the shoe to slip and break away from the nail with corresponding danger of injury to the operator exert ing leverage pressure upon the nail puller.

The invention eliminates these diiiiculties and 'further'removes the nails without injury to them so that they can be reused again and again. The invention is further characterized by preserving the vertical spacing of the operators hands for easy management of operations without the hands being endangered by relative moving parts as is the case with conventional nail pullers.

Another object of the invention is to provide a `nail puller which retains its grip upon the nail Aly clear of the wood and resetting itself for pulling the next nail. 4

A further object of the invention is to grip ,th

nail only when the jaws are deep enough in the wood to close upon the shaft of the nail below the head and then to close the jaws with a com- A heavy slip sleeve bination of cooperating forces which not only guides the jaws to a closed position but locks the jaws closed with a reaction force which preferably provides a lost motion between the nail puller body and the board holding the nail so that initial reverse movement of the parts gains the advantage of an inertial head start to jerk andv unseat the nail from its set position to start its withdrawal. With the head start thus provided, the full weight of the nail puller body is brought into play in preference to the use of only part thereof or the use of additional weight.

Furthermore, the invention exerts a tugging action without hammering and eliminates objectional noise generally accompanying conventional nail pulling.

Other and further objects of the invention, including simplicity of construction and operation, will .become apparent from the drawings, the description relating thereto, and the appended claims. f

Referring now to the drawings,

Fig. 1 is a front view, partly in section,v of a construction embodying a preferred form of the invention in position ready to pull a nail;

Fig. 2 is a sectional view of the construction shown in Fig. 1, as taken upon line 2-2 Fig. 3 is a bottom view of the lower end of the construction shown in Fig. 1;

Fig. 4 is a section taken upon line i--li in Fig. 1;

Fig. 5 is a section taken upon line 5 5 in Fig. l

Fig. 6 is a diagrammatical View taken from the front of the construction shown in Fig. 1 with the jaws open and the nail pulling head in raised position;

Fig. '7 is similar to Fig. 6 showing thejaws as they contact the wood around a nail head;

Fig. 8 shows another position of the nail pulling head in which the jaws have penetrated the wood and closed upon the nail; and

Fig'. 9 shows another position of the head with-the nail withdrawn and about to be ejected.

The invention contemplates driving two pivoted jaws into a board on opposite sides of a lnail head and, as the jaws move in, contracting and locking the jaws in contracted position below the nail head; lifting the jaws a full distance ,to remove and clear the nail from the board, and 'thereafter 'expanding the jaws to discharge the -nail without mutilation. It is preferred that the jaws be so mounted on a guideway member that they overrun the guideway when driven into the board, thus lifting the guideway member clear of the board during the time that the jaws are being contracted around the nail. This readies the nail puller to exert the extra heavy force needed to start the nail by providing a moment during which the relative movable parts of the puller acquire a relative momentum before effort is exerted upon the nail. Under this relative momentum the guideway member again engages the board with a, blow and reaction effort sulcient to dislodge the nail from its set position prior to fully withdrawing the nail.

The apparatus employed embodying the invention includes a fluid actuated piston I disposed in a cylinder II and a piston rod I2 connected thereto which slides in and out through a front head I3 on the cylinder. A spacer I4 upon the piston rod determines the outward limit of movement. A second or rear head I5 is provided at the upper end of the cylinder and the two heads are tied together by stud bolts I6 and nutsv I1 disposed at opposite ends thereof. Two

vof the nuts upon one side and at the front end of the cylinder secure a laterally projecting handle 2i] in place, while two nuts upon the opposite side and at the back end of the cylinder secure a second handle 2I in place so that the device can be manipulated by holding the handle 23 in the left hand and the handle 2| in the right hand.

The piston is moved by fluid pressure such as air under a commonly used pressure of ninety pounds per square inch. The air is received through the nipple 22 threaded in the rear head I5 and directed into the chamber 23 of a valve 24 which has a slide element 26 and plate urged to one limit of its movement by a spirng 25. The slide element at the end opposite the spring 25 has a push rod 21 extending axially therefrom. The rod passes through gland packing 28 and into engagement with the short arm 30 of a lever SI pivoted to the rear handle 2| as at 32. A depressing of the lever 3I drives the element 26 against the spring and moves it to its secondary position. Releasing the handle permits the spring to return the element 26 to its starting position.

A slide valve member 26a is engaged and driven by the element 26. This member is disposed so as to slide over pairs of ports I9 and I9a. In the starting position shown, the pair of ports I9 is in communication, connecting the upper end of the cylinder to the atmosphere. One of the ports I9a of the second pair is open to the space 23 to admit air to the lower end of the cylinder, and the vent port of the pair is closed. When the handle 3I is pressed, the slide valve member 26a is moved to the other side, connecting the pair of ports I9a to vent the lower part of the cylinder and connecting one of the ports I9 to the space 23 to supply air to the upper part of the cylinder.

In its starting or resting position the air under 'pressure is directed to ilow into the cylinder on the rod side of the piston through the valve port I9 and a conduit 33 running down the outside of the cylinder. This returns and holds the piston at its rearward position. The rear portion of the cylinder is vented to atmosphere to permit this. In the secondary position of the valve, as when the lever is depressed, the front end of the cylinder is vented to atmosphere and the air under pressure is directed into the cylinder behind the piston to force it frontwardly.

Thus, depressing the lever drives the piston rod downwardly with a quick, power-driven action,

and releasing the lever will cause a quick, powerdriven lifting or retraction of the piston rod.

This control of the piston can be accomplished by the right hand while the cylinder is held in supported working position.

A sleeve guiding the piston rod I2 is held in place upon the forward head I3 by machine screws 36 and has attached to it as shown in Fig. 2 a bar 31 which has a, longitudinal groove 38 on the piston rod side of the bar. The end face of the bar is knurled as at 40 and the two adjacent corners on the piston side of the bar are faced 01T as at 4I to leave a pointer contour 42. The pointer is used to locate the bar `with respect to a nail 43 and the knurled end face 4B prevents slipping. At the upper end of the groove 38 an interchangeable stop member 44 is held against longitudinal displacement by the head of a machine screw 45 resting snugly in a hole `4'6 in the bar.

The exposed end of the piston rod I2 is threaded as at 41 to engage in a threaded boss 5I upon a housing member 50 where it is held against loosening by a setscrew 52. The housing member slides up and down on the bar, against the front face 53 thereof, and is guided by a cover member 54 channeled as at 55 to receive the bar as held in place by machine screws 56 whose heads are preferably countersunk in the housing where the stock is thick enough to receive them without weakness.

The housing member and cover member define a cavity 51 within which the nail gripping and release elements are supported. Referring to Fig. 6, two jaw elements are pivoted to each other as at the pivot pin 58 located intermediate their ends so that the expansion of the arms 6I! causes the jaws 6I to close towards each other.

The jaws are curved inwardly like the ends of a crescent and preferably are made out of tool steel to withstand striking against hard wood, metal binding tape or sheet steel. The arms are shaped to define a space between them and tapered upwardly at 62 to provide camming surfaces between them. A block or cam 64 is slidably mounted in the groove 38 upon the bar 31 where it lies between the arms 6U inside the camming surfaces 62, the upper corners 65 engaging the camming surfaces being rounded for easy sliding along the camming surfaces. As shown in Fig. 2, the block has a well 66 in it receiving a spring pressed ball 61 engageable in a detent 68.

A tension spring 1U, with upset loops at each end secured against the outer faces of the arms by screws 1I, urges the jaws BI to their open position by drawing the arms towards each other.

At the upper or rearward limit of the housing movement, the floating block engages the stop 44 and is held or driven thereby from between the ends of the arms 60. At the lower or forward limit of the housing movement, the oating block engages the lower end of the groove and is held there as the housing approaches its limit of movement as determined by the length of the sleeve I4. During the last increment of downward movement under the force of the piston, the block is stationary but moves along the camming surfaces 62 as the housing carries the arms downwardly and moves between the .arms to accomplish their separation and the corresponding closure of the jaws. In this position the ball engages in the detent to keep the block from jarring out of position on `the back stroke until such time as the stop 44 engages the block and carries it from between the ends of the arms as already mentioned. I

The driving force between the housing and the jaws is carried mainly at two points so that the load is not only distributed between several elements, but the jaws are steadied against veering. This is accomplished by two pins 14, one upon each arm, slidable laterally in transverse grooves in the housing as the arms are expanded. Lateral expansion is allowed iorby mounting the head 'l2 of the pivot pin to slide in a vertical groove 'i3 in the housing. The two pins 74 carry most of the load of protraction and retraction insofar as the work effort upon the jaws is con-- cerned. However, these pins sharethe load and in conjunction with the pivot pin support the jaws against veering when driven downwardly to grasp the nail below the head.

In operation, the resting position of the head is shown in Fig. 6 where it is held in its re-y tracted position by air pressure admitted to the cylinder on the rod side of the piston as when the valve 26 is in its resting position under the influence of the compression spring 25. The pointer 42 is located opposite the head 39 of the nail 43 where it is embedded in a wooden board 29. This is best accomplished by holding the handle in the left hand and the handle 2i in the right hand.

The lever 3| is then depressed. This moves the valve to its alternate position, air be1ow the piston is vented to the atmosphere, and air under pressure enters the cylinder above the piston. This drives the piston downwardly, carrying with it the head and the floating block 64.

The next station of interest is reached when the block 54 reaches the end of the groove 353 in its downward movement as shown in Fig. 7. At this time the jaws have begun to pierce the wood and the rounded upper corners G5 of the block 64 engage the cam surfaces 62 of the arms 6B. In this position the lower end of the bar 3i is still in contact with the wood and the head is still moving downwardly.

The downward drive of the head has ended in Fig. 8. The jaws have been driven deeper into the wood. The arms 6B have been driven along the rounded corners and havebeen expanded by the block to close the jaws around the nail head. The spring pressed ball 61 has engaged in the detent 68, and the overthrow provided .between the bar 31 and the head 50 as determined by the length of the sleeve I4 has operated to raise the lower end 4U of the bar away from the board as a preferred preliminary to the back or reverse stroke of the piston.

The lever 3| is then released. The valve resumes its normal position. The v.upper portion of the cylinder is vented to the atmosphere and air under pressure is fed into the cylinder below the piston. When this occurs the head and bar begin to move with respect to each other with quick acceleration. They bar being raised above the board a short distance enables the building up of this relative inertial movement between the bar and head before a withdrawing force is exerted against the nail. This movement in substance builds up sufficient energy that when the bar again engages the board with a blow-like force, the reaction jars the nail loose from its embedded position and the piston thereafter merely tugs amoving nail. Invariably the nail is loosened and withdrawn with one application of force but if it is not, manipulation of the lever will cause repeated blows and reaction of elements until the -nail is dislodged enough that the direct pull of the piston is adequate to complete withdrawal of the nail.

The next station of interest is then shownin Fig. 9'where the nail has just cleared the board and is about to be ejected. The nail is straight and as good as new for reuse. As shown, the block has just come into contact with the stop 44 and can go no further. But the head having a predetermined distance yet to go disengages the detent 68 and moves the arms from off the sides of the block whereupon the block is freed and the arms are also freed to be contracted by the compression spring 10 with sufficient snap and force the fracture they impose upon the wood. v.The :shoulder is useful in preventing vthe-jaws from going too deep if a soft spot in the woodis encountered. This preserves the overthrow or lost motion lift of the bar from the Wood so that inertial starting blow is assured each time.

Consequently, although a preferred embodi- 'rnentis shown, it will be apparent to those skilled `in the art from the description of preferred forms how various and further modifications can be vmade without departing from the spirit of the invention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In a nail puller, the combination of a guide member, a slide member, a loose element having cam surfaces thereon carried by one member for movement with respect to the other member, a pair of stops for limiting movement of the loose element with respect to the other member, nail gripping jaws pivotally mounted on the slide member including 'actuating arms cooperating with-said cam surfaces, said element being disposed between said arms and movable when one stop is approached to close said jaws by displace- ,Y ment of said arms and to release the jaws when the other stop is reached by movement from be- -tween the arms, said slide member having a greater distance of travel than said element.

2. Ina nail puller, a support member for engaging a workpiece, a pair of jaws reciprocably mounted with respect to said member for gripping a nail in the workpiece, and means for driving the jaws beyond the support member into the workpiece around the nail to lift the support from n contact with the workpiece, said means also driving the support into contact with the workpiece vinary to and as a part of applying withdrawing Y movement of the jaws upon the nail.

in close proximity to the nail to deform a portion of the workpiece surrounding the nail prelim- 3. In a nail pull-er, a support member for engaging a workpiece in close proximity to the nail 'portion f the workpiece proximate to the nail and develop an inertial blow to move a portion of the workpiece with respect to the nail to overcome starting friction and apply withdrawing movement Aof the nail grasping member upon th nail.

4. In a nail puller, the combination including a guide member, a slide member, a loose element carried by the slide member, a pair of stops on said guide member for limiting motion of said loose element in both directions; a pair of jaws pivotally mounted on said slide member and including actuating arms, said element bearing against said arms when one stop is approached to close the jaws by displacement of the arms and moving away from said arms when the other stop is reached to permit the jaws to open, and resilient means for opening said jaws under such conditions.

5. In a nail puller, a support member for engaging a workpiece, means for reciprocably mounting a pair of jaws for gripping a nail in the workpiece, said means being so constructed and arranged as to permit said jaws to move to a position extending beyond the end of the support member into the workpiece around the nail to lift the support from contact with the workpiece a distance substantially in excess of the normal penetration of the jaws in the workpiece, means for driving the jaws to said position from a retracted starting position, said last mentioned means also driving the support into contact with the workpiece to develop an inertial movement preliminary to applying withdrawing movement of the jaws upon the nail.

, 6. In a nail puller, a support member for engaging a workpiece, a head including a pair of jaws reciprocably mounted on said member, said jaws being adapted to penetrate said work piece, the clearances between said member and said head being such as to permit said pair of jaws to vbe moved to a position beyond the end of the -support member a distance substantially greater than the penetration of the workpiece by the jaws to lift the support a substantial distance from contact with the workpiece, and means for driv.. ing the jaws to such position, said last mentioned means also driving the support into contact with the workpiece to develop an inertial movement preliminary to applying withdrawing movement of the jaws upon the nail.

7. In a nail puller, a piston memberand a cylinder member including means for reciprocating the piston under power in both directions, a support element for engaging a workpiece carried by one of the members, a pair of jaws for gripping a nail in the workpiece carried by the other member, said jaws being adapted to penetrate said work piece, the clearances of said members being such as to permit said jaws to extend to a position beyond the support member a distance substantially greater than the penetration of the workpiece by the jaws at one limit of relative movement between the jaws and the support, and means for opening and closing said jaws at opposite limits of said relative movement.

8. In a nail puller, the combination of a guide member, a slide member mounted for reciprocable movement with respect to said guide member, jaws carried by said slide member to grip a nail to be pulled, a loose cam element for actuating said jaws, said element being loosely carried by said slide member for longitudinal movement with respect to the other member, and stops on one of said members for limiting movement of said cam element, said element closing said jaws when one stop is reached and releasing said jaws when the other stop is reached and said slide member having a greater distance of tuating said jaws, and stops for limiting movement of said movable element with respect to said guide member, said means for actuating said jaws closing said jaws when said movable element reaches one of said stops and opening said jaws when it reaches the other stop and said slide member having a greater distance of travel than the movable element.

10. A nail puller comprising a guide member, a slide member, a loose element having a cam surface' thereon carried by the slide member for movement relative to the guide member, a jaw pivotally mounted on the slide member and having an actuating arm, a pair of stops for limiting movement of said element, said element being movably mounted adjacent said arm and movable when one stop is approached to close said jaw by displacement of said arm as the cam surface cooperates with said arm and to release said jaw when the other stop is reached by movement relative to said arm, said slide member having a greater distance of travel than said element, and means for reciprocating said slide member.

11. The method of `withdrawing a nail embedded in a workpiece including moving a nail engaging element toward said workpiece at a relatively high velocity to cause said element to penetrate said piece beneath the head of said nail, moving the element into contact with said nail to engage same, and striking a blow against the workpiece in close proximity to said nail head while simultaneously exerting an 'upward force upon said element to withdraw said nail.

CLARENCE N. BUCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 779,028 Condon Jan. 3, 1905 1,516,155 Santarelli Nov. 18, 1924 1,771,712 Jimerson July 29, 1930