US2894720A

US2894720A - Pinch bar

Info

Publication number: US2894720A
Application number: US589036A
Authority: US
Inventors: Raymond W Bennett
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-06-04
Filing date: 1956-06-04
Publication date: 1959-07-14
Anticipated expiration: 1976-07-14

Description

PINCH BAR Filed June 4, 1956 IQIYMO/VD WEE/W577 26 H43 28 24 2 W PINCH BAIR Raymond W. Bennett, 'Ilion, N.Y.

Application June 4, 1956, Serial No. 589,036

2 Claims. (Cl. 25425) This invention relates to prying tools, and more particularly to a multipurpose pinch bar or crow bar which may be used in a variety of new ways and perform many functions heretofore impossible with the ordinary pinch bar.

Pinch bars have been known for many years in the art and have generally consisted of an elongated handle portion having on one end the well known curved claw portion and on the other a substantially straight wedge sur face. This has been substantially unchanged for many years. According to the present invention I have protates atent O vided a more useful pinch bar with the advantages of the conventional bar plus others and without many of the disadvantages of the conventional pinch bar.

It is an object of the present invention to provide an improved pinch bar that is more versatile in use than heretofore known. It is another object of the present in vention to provide a pinch bar with improved lever action that will not mar the surface upon which the bar is placed in its prying action. It is another object of the present invention to provide a pinch bar with a plurality of removable leverage olocks that may be substituted to provide different mechanical advantages for use in difierent materials and different sized operations. It is another object of the present invention to provide a pinch bar of an improved design which provides better operation in confined spaces. It is a further object of the present invention to provide a pinch bar of improved design that will allow removal of nails and the like from relatively soft and delicate surfaces without the necessity of special protective coverings therefor. It is a further object of the present invention to provide a pinch bar whereby nails may be pulled without bending thereof. It is a still further object of the present invention to provide a pinch bar that Will remove nails and the like from a surface without scufiing or sliding along said surface. These and other and further objects will be in part apparent and in part pointed out as the specification proceeds.

In the drawings:

Figure 1 is a top plan view of a pinch bar according to the present invention lying on its side with the elongated handle portion broken away from the sake of clarity and compactness;

Figure 2 is a cross-sectional view on line IIII of Figure 1;

Figure 3 is a crosssectional view on line III-III of Figure l; and

Figure 4 is a fragmentary view partially in section, similar to Figure 1, showing a still further embodiment of the present invention.

Referring now the Figure 1 the pinch bar 10 comprises generally an elongated handle portion 12, shown broken in the middle in Figure 1, having at one end the usual large curved portion 14 with the usual claw wedge surface 16 at the extremity thereof. The other end of the handle portion 12 terminates in the usual wedge surface 18, however, as can be readily seen in Figure l wedge surface 18 is angularly offset in the same direction 2,894,720 Patented July 14, 1959 ICC as the curved portion 14 at the other end. of the handle 12.

Mounted in about the middle of curved portion 14 is a leverage block 20 which has an outer convex surface 22 and an inner concave surface 23 curved so as to fit around the outer surface of the curved end 14 of the bar 10. Inner surface 23 has therein a groove 24 to further accommodate bar 10. As may be seen in Figure 3, the block 20 has therein a pair of holes 26 which are internally threaded as at 28.

Positioned on the opposite side of the curved portion 14 from block 20 is a clamping block 30 which has there- 'in holes 32 with countersunk top openings 34 adapted to receive therein a pair of bolts 36 which are threaded and adapted to engage in the holes 26 so as to clamp the block 20 about the bar 12 at portion 14.

As may be seen more clearly in Figure 4 the curvature of surface 22 is chosen such that it provides a smoothly rocking fulcrum for the claw wedge on surface 40 as it engages a nail or the like therein. This curvature is such that as the handle of the pinch bar is rotated in the clockwise direction in Figure 4, a substantial-1y straight lifting force is applied to the nail 38 such that it is removed with very little, if any, bending.

Also it may be seen that the curvature of surface 22 is such that instead of a normal decline in the mechanical advantage for claw wedge surface 16 as pinch bar 10 is used the mechanical advantage is maintained or even increased to a slight extent as the nail or other object is raised from the surface 40. This construction automatically compensates for the increased length of the nail or other object as it removed from the board and thus helps to prevent bending thereof and obviates the necessity of adding the customary block of wood.

As may be clearly seen in Figure 1 the clamping block 30 has a slightly rounded inner surface such that the block 20 may be positioned at the most advantageous point on the curved portion 14 so as to cooperate to the fullest extent with the claw wedge surface 16. A groove (not shown) may also be provided if desired. The block 20 is applied by merely slipping the bar between the blocks- 30 and 20 and then tightening the bolts 36 to clamp the bar securely in groove 24 in block 20. This clamping action can perhaps be better seen in Figure 3.

Referring now to Figures 1 and 2 there is shown a second leverage block 42 positioned adjacent the other end of the handle 12 in cooperative relationship to the wedge surface 18. As may be seen this block 42 is normally of a somewhat smaller configuration than the block 20 and has an outer curved surface 44 with a slightly different curve than that of surface 22. Block 42 has therein a groove 46 similar to that of block 20 and also has therein screw holes 48 to receive therein the screws 36 in cooperative relationship with block 30 so as to clamp block 42 about the bar 10. The block 30 is the same as that used with the leverage block 20 and in cooperation with block 42 can readily clamp it about the bar 10.

Block 42 may be adjusted along the handle portion 12 relative to surface 18 to give any desired mechanical advantage for removing a nail, board, or other object from any desired surface. The curvature of surface 44 may be varied for the particular application of the tool as well as its position relative to surface 18.

Leverage block 42 like block 20 cooperates with its surface 18 to provide a substantially constant or increasing mechanical advantage and to prevent the bend of the nail or the like or severe marring of the board as it is removed from the surface to which it is attached.

As may be readily seen in Figures 2 and 3 the

blocks

20 and 42 are many times the width of the bar 10. This prevents undue maning of the surface 40 or similar surface from which the nail is to be removed and also provides a greater fulcrum support so that there is less likelihood for the bar to rotate and slip out from under the desired object providing a more stable and useful tool of increased flexibility. In actual use I have found a width of from twice to ten times the width of the bar to be entirely satisfactory for the blocks and 42 the exact width depending upon the particular bar in question and the application to which it is to be put.

As may be seen in Figures 2 and 3 the

slots

24 and 26 are made of a suflicient size so they may take a variety of sizes of bars 10 down to a minimum size until the bar rests in the bottom of the groove. At this point the

blocks

30 and 42 will be almost if not actually touching and a different size block will have to be used for smaller bars than that.

Referring now to Figure 4 there is shown a further embodiment of the present invention wherein the block 20' has substantially the same curvature as the block 20 and has cooperating therewith a clamping block 30' together with bolts 36 to clamp the block 20" about the bar 10' along its curved portion 14. In addition it may be seen an outer covering 50 is applied to the block 20'. Advantageously this is of a soft material such as rubber or fabric. In certain cases where metal is involved this covering may be a soft brass such that when the bar is used it will not mar the surface upon which the fulcrum must rest. It is believed to be obvious that the particular material chosen will depend upon the surfaces involved. Normally the covering 50 is softer than the surface to which the bar will be applied.

The covering 50 may be either permanent or removably attached to the block 20' depending upon its nature. Indeed it has been found in certain applications desirable to have a covering such as rubber removable so that as it is worn it can be replaced or so that it can be covered with other than rubber for certain applications. This covering 50 does not affect the operating characteristics of the pinch bar as set forth above, however it does give added protection and flexibility to the tool as described herein.

In the foregoing specific embodiments my invention has been shown applied to a pinch bar or crow bar type tool. It should be understood that my invention can be equally applied to other similar types of prying tools including the conventional claw hammer without departing from the scope of my invention.

While there is given above a certain specific example of this invention and its application in practical use, it should be understood that this is not intended to be exhaustive or to be limiting of the invention. On the contrary, this illustration and explanation herein are given in order to acquaint other skilled in the art with this invention and the principles thereof and a suitable manner of its application in practical use, so that others skilled in the art may be enabled to modify the invention and to adapt and apply it in numerous forms each as may be best suited to the requirement of a particular use.

I claim:

1. A multipurpose pinch bar tool comprising in combination an elongated handle, a claw wedge surface on one end of said handle bent back thereon at a substantial angle, a second Wedge surface on the other end of said handle disposed at a slight angle thereto, a leverage block assembly detachably mounted about said bar adjacent said claw wedge surface, said assembly comprising a smoothly curving serni-cylindrifor'm outer block member adapted to be mounted on the convex side of said curved bar surface, said block member having a transverse width at least twice the width of the bar to which it is to be attached and a length along said bar of at least twice the width of said bar, a thin protective surface covering member detachably secured about the outer surface of said semi-cylindriforrn block member, a clamping member adapted to be mounted on the inner side of said curved bar surface, a groove cut on the inner concave surface of said outer member adapted to receive therein the outer surface of the bar to which it is to be attached, a pair of threaded holes in the outer block member, a pair of countersunk holes in the inner block member, and a pair of threaded bolts adapted to extend through the holes in the inner block into threaded engagement with the holes in the outer block to clamp said blocks about the pinch bar adjacent said wedge surface in cooperating relationship thereto whereby a pinch bar having a substantially constant mechanical advantage and a wide non-marring fulcrum surface is obtained.

2, In a multipurpose pinch bar tool of the type having an elongated handle, a claw wedge surface on one end of said handle bent back thereon at a substantial angle and a second wedge surface on the other end of said handle disposed at a slight angle thereto, a detachable leverage block assembly comprising in combination a smoothly curving semi-cylindriform outer block member adapted to be mounted on the convex side of said curved bar surface, said block member having a transverse width at least twice the width of the bar to which it is to be attached and a length along said bar of at least twice the width of said bar, a thin protective surface covering member detachably secured about the outer surface of said semi-cylindriform block member, a clamping member adapted to be mounted on one side of said curved bar surface, a groove cut on the inner concave surface of said outer member adapted to receive therein the outer surface of the bar to which it is to be attached, a pair of threaded holes in one of said block members, a pair of countersunk holes in the other block member, and a pair of threaded \bolts adapted to extend through the countersunk holes into threaded engagement with said threaded holes to clamp said blocks about the pinch bar adjacent said wedge surface in cooperating relationship thereto whereby a pinch bar having a substantially constant mechanical advantage and a wide non-marring fulcrum surface may be obtained by simply attaching said assembly thereto.

References Cited in the file of this patent UNITED STATES PATENTS 119,770 Ives Oct. 10, 1871 584,189 Nelson June 8, 1897 773,813 Saegmuller Nov. 1, 1904 949,337 Trogner Feb. 15, 1910 2,472,040 Brookfield May 31, 1949