US3059300A

US3059300A - Strap end holder

Info

Publication number: US3059300A
Application number: US49303A
Authority: US
Inventors: Dwight P Noel
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1960-08-12
Filing date: 1960-08-12
Publication date: 1962-10-23
Anticipated expiration: 1979-10-23

Description

Oct. 23, 1962 D. P. NOEL STRAP END HOLDER Filed Aug. 12, 1960 United States atent i 3,059,300 STRAP END HOLDER Dwight P. Noel, Chester, Pa., assignor to American Viscose Corporation, Philadelphia, Pa., a corporation of Delaware Filed Aug. 12, 1960, Ser. No. 49,303 6 Claims. (Cl. 24-434) This invention relates to strapping tools and more particularly to an improved strap end holding means for a strap tensioning tool.

Over the years a wide variety of hand tools, some of them power operated, have been developed for drawing a steel strap taut about a box or package preliminary to securing the ends of the strap together. Generally, the strap is paid out from a roll or. coil and looped about the object to be strapped with the trailing portion of the strap overlapping the leading end. With many of the tools, the leading end of the strap is held securely while the trailing portion is engaged by a suitable device and drawn over the leading end until the desired degree of tension is obtained. The overlapping ends of the strap are then secured together by any one of various means, which may be applied by the same tool or by a separate tool, and the tailing end of the then tightly secured portion of the strap is severed from the supply.

The devices employed in steel band strapping tools for holding the end of the strap generally include a dog or pawl which is pivotally supported from one side and provided with teeth adapted to engage the strap and hold the same against a cooperating surface. The dog is generally spring urged about its pivot in engaging direction and must be manually rocked to released position when the end of the strap is to be inserted, the strap being inserted from the side, that is, the strap i moved sidewise beneath the dog. The dog is pivoted in such a way that its gripping action on the strap increases as the tension on the strap increases. Either the dog itself or the member on which it is mounted is usually provided with a slot through which the trailing end of the strap is inserted so that the overlapping portions of the strap are reasonably close together so as to facilitate the securing together of the overlapping portions.

While holding devices of the type referred to above are reasonably saisfactory for use with steel band strapping, they have not proven entirely suitable for use with other type of strapping such as paper or the more recently developed cord strapping which consists of a plurality of cords secured together side by side in the form of a flat tape or strap. The primary difficulty in using steel band type of end holding devices in tools for tightening cord strapping is that they damage the strap, sometime to such an extent that the strap breaks or pulls out of the holding devices before the desired degree oftension is reached. One of the reasons why they damage the non-metallic strap is that because of the cantilever mounting of the dog, the strap is gripped more firmly on the side adjacent the mounting of the dog, rather than uniformly across the width of the strap. This is not too objectionable when using steel strapping because the Uniform structure of the steel distributes the force throughout the body of the strap but with cord strapping it is essential that each cord be held if the full strength of the strap is to be realized since the pulling or tightening force cannot transfer from one cord to another.

It is the primary object of the present invention to provide, in a strap tensioning tool, an improved strap end holding means especially adapted for holding or gripping the end of a non-metallic strap.

It is a more specific object of the invention to provide, in a strap tensioning tool, a strap end holding means which 3,059,306 Patented Oct. 23, 1962 ice will not damage cord strapping or other non-metallic flexible strapping and at the same time be effective to securely hold the same before and after the strapping is placed under full tension.

Another object of the invention is to provide a strap end holding means of balanced construction, that is one which exerts equal pressure over the entire holding area.

A still further object of the invention is to provide, in a strap tensioning tool, a strap end holding means so constructed and arranged that the overlapping ends of the strap are in contact with one another whereby the securing togeether of said ends is facilitated.

Another object of the invention is to provide a strap end holding means with which the end of the strap may be quickly engaged and from which it may be readily released after tightening.

Other and further objects, features and advantages of the invention will become apparent as the description of certain preferred embodiment thereof proceeds.

Referring now to the drawing:

FIGURE 1 is a side elevational view of a strapping tool' embodying the invention and showing its use in a strapping operation;

FIGURE 2 is a perspective view showing one form of the strap end holder;

FIGURE 3 is a sectional view taken on the line IIIIII of FIGURE 2 and showing the strap end holder in strap holding position;

FIGURE 4 is a View similar to FIGURE 3 but showing the gripper in non-gripping position;

FIGURE 5 is a perspective view of a modified form of the invention; and i FIGURE 6 is a sectional view showing the modified form in operation.

Referring first to FIGURE 1 wherein is shown more or less diagrammatically one of many forms of strapping tool in which the trap end holder of the present invention may be eifectively embodied, the tool comprises generally a U-shaped frame 10 having downwardly directed legs 11 and 12 and an integral handle 13. The tool is shown in the process of tightening a strap 14 about a box or package partially shown at 15 and is supported on the package by the leg 12 and a foot 16 formed integrally with or secured to the leg 11. The strap end holding device is generally indicated at 17 in FIGURE 1 and the leg 12 carries the mechanism for drawing the strap tight.

The strap tightening mechanism is only schematically shown inasmuch as it may take various forms and is not per se a novel feature of the present invention. As shown, this mechanism includes a rotatably mounted drum 18 provided with diametric slots 19 for holding the trailing end or some intermediate portion of the strap. A gear 20 is operatively connected to drum 18 and said gear is meshed with a gear 21 rotatable on a shaft 22 carried by the frame 10. An operating handle 23 is also rotatably or swingably mounted on shaft 22 and carries an operating pawl 24 which, when handle 23 is moved clockwise, causes the gear 21 to rotate gear 20 and drum 18 in a direction to wind up and tighten the strap, one end of the strap being held by the holding device 17. A holding pawl 25 is spring urged into engagement with the gear 20 and prevents retrograde rotation of drum 18 during counterclockwise movement of handle 23. When the strap reaches the desired degree of tightness the overlapping portions thereof are secured together by crimping a seal 26 therearound. Various devices may be employed for performing the sealing operation and as is known, such devices are frequently incorporated in'the same tool that tightens the, strap. After application of the seal, the strap is out between the seal and drum 18 and as is also known, a cutter may be incorporated in the stretching or tightening tool for this purpose. After the strapping operation is thus completed, the operating handle 23 is moved to its full counterclockwise position indicated by dotted lines and the pawl 24 contacts an upstanding ear of holding pawl 25 to thereby cause both pawls to release their respective gears and free the drum 18.

Referring now to FIGURES 2, 3 and 4 for a detailed description of one form of strap end holding means constructed in accordance with the present invention. The device comprises a main body member, which in this case is the foot 16, and a gripper element 30 rockably mounted therein. As shown, the main body member is formed so as to provide a slot or cavity 31 between two

parallel legs

32 and 33, with leg 32 being shorter than leg 33. A semicircular groove 34 is cut into an intermediate portion of leg 33 and a matching semicircular groove 35 is cut into the outer end of leg 32. Gripper element 30 is in the form of a solid circular cylinder and is rockably or rotatably mounted in the grooves 34 and 35 and extends into a cylindrical opening bored into the thick portion of the body member in alignment with the grooves 34 and 35. In manufacture, grooves 34 and 35 and the aligned bore in the thick portion of the body member are formed in a single drilling operation and it will be apparent that the gripper element is inserted from the right as viewed in FIGURE 2 and cannot escape sideways from the groove 34 because of the overhanging end of leg 32.

A small bore 36 is provided in the foot or main body member 16. Bore 36 is transverse to and intersects the bore accommodating the inner end of gripper element 30 and a resilient means in the form of a bent Wire spring 37 is mounted within bore 36 and engages a flat surfaced cut-out 38 provided in said gripper element. Spring 37 is held in place by a bent end 39 thereof which snaps into a small hole bored through the bottom of member 16 so as to intersect bore 36. Spring 37 prevents gripper element 30 from falling out endwise and serves a further function presently to be mentioned.

A portion of cylindrical gripper element 30 is cut away to form a channel 40 therein, the bottom 41 of which extends approximately diametrically across the cylinder. The spring 37 normally holds the gripper element in the position shown in FIGURES 2 and 4, so that channel 40 provides an opening between said gripper element and the lower leg 33 of the main body member.

In use, the free end of the flexible strap is inserted through the opening between the gripper element 30 and the lower leg 33 and into the cavity 31 located behind the gripper, as shown in FIGURE 4. Preferably, the surface 41 is flared away from leg 33 at the introduction side of the holder as indicated at 42 to facilitate the insertion of the strap. With the end of the strap thus positioned, the strap is then wrapped about the package and the trailing portion thereof engaged with the drum 18 for tightening, as previously mentioned. The act of wrapping the strap about the package causes the strap to lie against the top of leg 32 as shown in FIGURE 3 and when the strap is pulled a portion thereof engages an edge 43 of gripper element 30 and rocks said gripper against the action of spring 37 to cause another edge 44 to move into engagement wih the strap and pinch the same against leg 33 of the main body member. There are in reality two distinct forces which hold the end of the strap; one, a snubbing action about the edge 43 and the end of upper leg 32, and two, the squeezing or pinching force of edge 44. This distributes the entire holding force in such a way that the end of the strap is not damaged or cut.

Since gripper element 30 is supported throughout its entire length by the main body member, the edge 44 acts uniformly across the entire face of the strap, whereas a cantilever supported gripper, particularly when it becomes wo'rn, will have its greatest gripping action on the side adjacent its mounting. This uniform application of pressure all the way across the strap is most important when using cord or paper strapping if the full strength of the strap is to be utilized. Another feature of the present arrangement is that the overlapped portion of the strap is in direct contact with the portion adjacent the held end and this facilitates the application of seal 26, as will be appreciated.

That form of the invention shown in FIGURES 5 and 6 is a modification of that described above. In this form, the main body member consists of a member in the form of a solid circular cylinder. Member 50 is screwed into or otherwise secured to the leg 11 of the tool and protrudes outwardly therefrom as shown in FIGURE 5. A slot 51 is milled into member 50 to form a cavity into which the end of the strap is inserted. Rotatably or rockably mounted upon the body member 50 is a cylindrical gripper element 52 in the form of a split sleeve having a channel 53 therethrough formed by the facing

end portions

54 and 55 of the sleeve.

A slot 56 is provided through gripper 52 near its inner end and said gripper is held on body member 50 by a pin 57 extending through slot 56 and screwed or otherwise secured in said body member. A spring or like resilient means 58 is secured at one end to pin 57 and at its other end to a pin 59 extending from gripper 52. Spring 58 normally holds gripper 52 in the position shown in FIGURE 5 with one end of slot 56 abutting pin 57. In this position channel 53 is aligned with cavity 51 so that the end of the strap may be inserted through said channel and into said cavity.

In that form of the invention shown in FIGURES 5 and 6, after the free end of the strap is inserted into the holding device, the strap is led around the package and engaged with the drum 18 for tightening, as above described. As the strap is pulled around the package, it engages the edge portion 54 of gripper element 52 and rocks said element about body member 50 against the action of spring 58 whereupon the edge portion 55 engages the strap and pinches it against said body member as shown in FIGURE 6 to thus securely hold the end of the strap. Since gripper element 52 has a sliding fit with body member 50 and the edge portion 55 is parallel to the slot 51, uniform pressure is applied across the entire face of the strap even though the device as a whole extends cantilever style from the leg 11. As previously mentioned, this is an important feature of the present invention. If it is desired to eliminate the canilever construction of that form of the invention shown in FIGURES 5 and 6 and thereby increase its overall strength, the body member 50 may be supported at both ends, for example by making said member longer than sleeve 52 and securing both ends in brackets provided on a foot of the tool such as foot 16.

Having thus described certain preferred embodiments of the invention, what is claimed is:

1. In a strapping tool having means for holding one end of a flexible strap and means for tensioning the strap about an object; an improved strap end holding means comprising a stationary body member, means providing a cavity in said body member, a gripper element rockably mounted on said body member, means forming a channel in said gripper element, means resiliently positioning said gripper element so that the channei therein is aligned with the cavity in said body member whereby the end of a strap may be inserted through the channel in said gripper element and into the cavity in said body member, said cavity having a bottom which defines the fully inserted position of the strap and thereby facilitates the proper positioning of the strap, said means forming the channel in said gripper element having a portion adapted to be engaged by the strap to rock said gripper element, and said means forming the channel in said gripper element having a second portion adapted to move into contact with the strap when said element is rocked 5 to pinch the strap between said element and said body member.

2. The device set forth in claim 1 wherein said gripper element comprises a circular cylinder and is rotatably supported throughout its length by said body member.

3. In a strapping tool having means for holding one end of a flexible strap and means for tensioning the strap about an object; an improved strap end holding means comprising a stationary body member, a gripper element rockably mounted on said body member, means forming an opening between said cripper element and said body member whereby an end of a strap may be inserted therebetween, cavity forming means in said body member adjacent and behind said gripper element whereby the end of the strap may enter into the cavity after passing through the opening between the gripper element and body member, said cavity having a bottom which defines the fully inserted position of the strap and thereby facilitates the proper positioning ofthe strap, said gripper element having a first portion adapted to be engaged by the strap to rock said element and having a second portion adapted to move into contact with the strap when said element is rocked to pinch the strap between said element and said body member, and resilient means normally holding said gripper element in unrocked position.

4. The device set forth in claim 3 wherein said first portion of said gripper element is flared away from said body member to facilitate the introduction of the strap into the opening between said gripper element and said body member.

5. The device set forth in claim 3 wherein said gripper element comprises a solid circular cylinder having a portion thereof cut away to provide the opening between said element and said body member.

6. The device set forth in claim 5 wherein both ends of each cylinder are rotatably supported by said body member.

References Cited in the file of this patent UNITED STATES PATENTS 730,331 Anderson June 9, 1903 1,042,529 Campbell Oct. 29, 1912 1,250,599 Lee Dec. 18, 1917 1,272,944 Green July 16, 1918 1,811,738 Williams June 23, 1931 2,539,333 Silbermann Jan. 23, 1951 2,557,877 Klusion June 19, 1951