US 2737070 A
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March 6, 1956 D. DIBNER 2,737,070
TOOL WITH FULL STROKE COMPELLING RATCHET MECHANISM Filed Sept. 18, 1953 2 Sheets-Sheet 1 l\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ I l 36 INVENTOR.
lq- J0 David Dilmer M 1 BY 38 36 W ,1 ORNEZ D. DIBNER March 6, 1956 TOOL WITH FULL STROKE COMPELLING RATCHET MECHANISM Filed Sept. 18, 1953 2 Sheets-Sheet 2 T001. WKTH FULL STROKE COMPELLING RATfiHET MEHANISM David Dibner, South Norwalk, Coma, assigncr to Enrndy Engineering Co. Inc, a corporation of New York Application SeptemberlS, 1953, Serial No. 381,049
Claims. (Cl. 311- 19) My invention relates to a ratchet controlled compressing tool which requires a complete closing cycle of the compressing surface before the tool can be opened to release the work piece.
Such tools are used, for example, in the form of pliers for crimping electrical connectors to wires. A connection not properly crimped may fail electrically and mechanically. A ratchet mechanism therefore is provided to insure completion of the crimping operation.
The prior devices, I have found, employ an excessive number of parts, some of which are costly to produce and assemble. Moreover, they maybe tampered with to avoid the restriction which they are designed to impose on the user.
Accordingly, objects of my invention are to provide a ratchet mechanism with a reduced number of parts, simple to manufacture and assemble; a ratchet mechanism which is relatively tamper-proof, and in which may be combined a jaw opening mechanism operable at the completion of each closing cycle.
These and other objects of my invention are accomplished and my new results achieved as will be apparent from the device described in the following specification, particularly pointed out in the claims, and illustrated in the accompanying drawing, in which:
Fig. 1 is a side elevation of a linear form of sliding ratchet mounted on a pair of pliers;
Fig. 2 is a top elevational view of the outer box-like slide having a tongue-like spring;
Fig. 3 is a similar view of the inner slide having ratchet teeth;
Fig. 4 is a longitudinally sectioned view of the assembled slides, with the spring shown in various positions indicated by dot-dash lines;
Fig. 5 is a transverse sectioned view taken in the plane 5-5 of Fig. 4;
Fig. 6 is a side elevation of an elbow type of sliding ratchet mounted on a pair of pliers;
Fig. 7 is a top elevational view of the outer compartment like slide having an inwardly projecting pawl;
Fig. 8 is a similar view of the inner slide having ratchet teeth;
Fig. 9 is a sectional view of the outer slide and spring through the assembled unit.
One embodiment of my invention is illustrated in Figs. 1 to 5, wherein I have employed a so-called in-line ratchet 10 for accomplishing the objects of my invention. This comprises inner and outer sheet metal slides 12 and 14, respectively, slidable one within the other. They may conveniently be made of sheet metal spring steel or heat treatable cold rolled steel.
When used to control the jaws of a pair of crimping pliers 16, such as is illustrated in Fig. 1, each end of a slide is attached to a handle of the pliers. Thus, the terminal end 18 of slide 12 is perforated as at 20 to receive a pin 22 which mounts the slide pivotally to perate'nt forated ear 24 of handle 26. Similarly, the terminal end 28 of slide 14 is pinned as at 30 to ear 31 of handle 32.
Inner slide 12 is rectangular in cross-section and comprises bottom, side and top walls 34, 35, and 36, respectively, the top wall being split longitudinally to provide passageway 37, the two inner edges 38 of the top wall extending downwardly and terminating in teeth 39. At one end of the teeth 39, tabs 40 extend downwardly from the upper wall, and at-the other end tabs 42 extend upwardly, for a purpose which will be hereinafter explained.
The outer slide 14 is also rectangular in cross-section fitting around inner slide 12 to permit the sliding action. In the upper Wall 43, a T-shaped spring 44 is stamped taking the slightly depressed position, shown in Fig. 4, when released. The spring forms a pawl with the teeth of the inner slide.
When the handles of the tool are in the open position, the T-shaped spring is in its neutral position, as is indicated by dot-dash lines and reference numeral 44a. When the handles start to close, the outer slide 14 of the ratchet begins to move on inner slide 12 and the spring 44 runs up against bent tabs 42 which .guide the spring down inside slide 12 of the ratchet. As the parts of the ratchet continue to slide together, the spring begins to move over the teeth 39. This is the ratchet action. If the operator attempts to open the handle of the tool at the time, the spring is unable to return over the teeth. This prevents the ratchet from sliding apart and there fore prevents the operator from prematurely opening the handles of the tool.
When the tool is fully closed, the ratchet spring reaches the end of the toothed track and springs up to its neutral position shown in solid lines in Fig. 4. As the operator permits the handles of the tool to open, the spring reverses the direction of its travel and is lifted by the tabs 49 at the end of the track to slide freely on the smooth surface of the upper wall 34 of inner slide 12, until the two slides of the ratchet device are returned to their open starting position. The device is then ready to repeat the cycle.
The ratchet design includes a stop 46 on slide 12 which engages projection 48 of slide 14, thereby limiting the maximum opened position of the tool. The tool itself may be provided with a spring 50 to keep the tool in an open position.
The slides being made of sheet metal, the teeth and spring may be madeby stamping the slides respectively in the desired form. Spring 44, for instance, may be made by the T-shaped cut 52 in the upper wall 43 of slide 14, leaving intact tongue 44 to form the integral spring. Similarly, projection 48 is formed to limit the movement of the slides.
Instead of employing a linear form of sliding ratchet, a circular ratchet device 60 may be employed, as is illustrated in Figs. 6 to 9. This form comprises a toothed member 62, a pawl member 64, a connecting rivet 66 for holding the toothed pawl members in operable relationship to each other, and a torsion spring 68 which serves the double purpose of furnishing the return motive power for the toothed and pawl members and the spring action for spreading the handles 70 and 71 of the pliers 72, illustrated in Fig. 6.
The toothed and pawl members are each provided with extending arms 74 and 76, respectively, which are pivoted to integrally formed ears 78 and 80 of the handles by pins 82 which permit pivot movement of the members about the rivet 66.
The toothed member 62 is provided with a circularly formed bent flange 83, on the edge of which teeth 84 are formed. At the end of the track of teeth, upwardly and downwardly extending tabs 85 and 86, respectively, which are used to guide the pawl 87 formed inwardly in member 64 over and under the toothed track 84, in the same manner as takes place in the linear slide device of Fig. 1. Thus, when the handles of the pliers start to close, the tab 85 cams over pawl 87 causing the pawl to engage the toothed track on the underside of the flange 83. The pawl slides over the teeth and is prevented from the reverse or open movement of the handles. When the tool reaches the fully closed position, the pawl passes tab 86. On the reverse or open position, i. e. when the spring 63 forces the handle apart, the pawl slides on the smooth upper surface of the flange, on the side opposite the teeth, until it again passes tab 85. This is the maximum open position and the beginning of the closing cycle. The spring is coiled about the rivet 66 and its two ends are anchored to members 62 and 64 through apertures 88 and 89, respectively. Member 64 is provided with an upturned wall 95, the end 92 of which engages the projection 101 of member 62 to limit the open position of the handles.
Ledges 90 of the toothed member 62, and casing 95 extending from the pawl member 64 form shields which prevent tampering with the mechanism.
The circular rack and pawl mechanism may also be made of stamped sheet metal formed into the desired shape. Thus the tabs 85 and 86 are formed from cutouts 96 and 97, respectively, which provides passageways for the pawl in its cycle of movement around the teeth.
Instead of single pivot holes on the ends of arms '74 and '75 which are pinned to ears 78 and 8d of the handles, a series of holes, such as 93 and 99, respectively, can be provided which permits a predetermined range of pivot points in the arms for adjusting the mechanism to ac commodate the variances in manufacture. By this methd, a finer adjustment may be made in the stamped parts than can be obtained with a single pivot hole in each arm.
In the foregoing examples, I have illustrated both linear and circular forms of rack and pawl devices that may be made of stamped sheet metal with a minimum number of parts, suitable for large quantity production at low cost. The devices are simple to assemble and install on tools, and require a minimum of adjustment.
They are compact in design and contain the mechanical elements on the inside of the assembly preventing easy access by one seeking to modify the performance of the tool.
The racks and pawls are positive in action and cannot 4 be affected by the loosening of parts or the abuse expected under operating conditions. The ratchet mechanism can be adapted to more tools, and especially hand tools of the plier type.
I have thus described my invention, but I desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and, therefore, I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments here shown and described are only some of the many that can be employed to attain these objects and accomplish these results.
1. In a tool having a pair of jaws provided with working surfaces, a rack and pawl mechanism connected to said jaws for controlling the movement thereof; said rack and pawl mechanism comprising a rack member and a slide member having a pawl; said rack member having two co-extensive surfaces, at least one of which is toothed; a guide at the end of each surface for directing the pawl from one surface to the other, forming a cycle of operation of the pawl; means for connecting each of the members to a jaw, said pawl camming past the toothed surface upon the closing of the jaws and interlocking when the jaws are partially opened, one of said guides releasing the pawl to the other surface for permitting the jaws to be opened upon the completion of the stroke.
2. In the tool of claim 1, wherein the two surfaces are positioned back to back.
3. In the tool of claim 1, wherein the surfaces of the rack member extend linearly.
4. In the tool of claim 1, wherein the surfaces of the rack member extend circularly.
5. In the tool of claim 1, wherein the rack member is positioned inside the slide member.
References Cited in the tile of this patent UNITED STATES PATENTS 1,4l4,728 Enders May 2, 1922 2,618,993 Carlson Nov. 25, 1952 2,670,015 Reynolds Feb. 23, 1954 FOREIGN PATENTS 608,213 Germany Oct. 29, 1933