Patent Application
20120216657
The present invention relates to an adjustable locking pliers. More precisely the present invention relates to a simplified compact structure for such locking pliers.
Locking pliers are well known in the art. One such conventional device is known as a Vise Grip pliers. These devices have two jaws that may be locked on an object. The over-center locking mechanism is achieved through a fixed jaw attached to a body, a movable jaw pivoted to the body, a handle pivoted to the movable jaw, and a pivoting over-center link between the body and movable jaw that together cooperate to lock the jaws on a work piece when the handle is forced toward the body. The over-center mechanism includes a fine adjustment screw that controls the opening of the jaws over a limited range to accommodate articles of different sizes within the range and permits the over-center mechanism to lock.
Another common variation is known as adjustable and water pump pliers. These allow for a movable pivot location to adjust the jaw size range for a given handle position. Further locking pliers have been combined with an adjusting mechanism to provide an adjustable locking pliers. In this manner a locking pliers can maintain a relatively parallel jaw and fit a wider size range of objects to be gripped. Some designs, for example “auto adjusting” types require careful and unintuitive manipulation of handles of the pliers to adjust or maintain a jaw size.
However the prior attempts to combine locking and size range adjusting features have a required a bulky, inconvenient, or inefficient mechanism. One example is a pliers according to U.S. Pat. No. 3,981,209; a corresponding product is sold by Facom of France as model #509. Another related Facom product is model #500 which includes features of the '209 patent along with features from French patent 1,100,105. These models are not easily adjusted and have a limp handle wherein there is no opening bias upon the lower jaw or the handle to stabilize the tool in a hand. Further without an opening bias there is no feedback for the position of the handle. All of the prior such designs have been awkward in appearance or use. According to the present invention a locking adjustable pliers includes a familiar appearance in a simple and compact design.
In the present invention a locking pliers includes a lower jaw that pivots about an upper body. The upper body preferably includes a fixed upper jaw at a front end. The pivot location between the lower jaw and upper body is movable between at least two distinct positions to enable at least two jaw opening ranges. For example in a small size range the pliers may be operated to lock the lower jaw in a minimum size to clamp directly against the upper jaw with a zero gap. The large size range has the lower jaw usually or always spaced away from the upper jaw.
According to the above description the jaw spacing may be changed in two ways. A continuous respective motion of the lower jaw occurs as the pliers are normally operated by moving a lever or handle pivotally attached to the lower jaw. This motion normally changes the respective angle of the jaws. A second type of motion is moving the jaws between the distinct small and large size ranges. Optionally more than two distinct pivot positions may be provided.
According a preferred embodiment of the invention a slot through the body extends generally vertically in the body or substantially perpendicular to the upper jaw face. A pin, protrusion, or equivalent structure of the lower jaw moves within this slot to allow the lower jaw to move toward and away from the upper jaw. The pin is fixed or located on the lower jaw. The pin preferably extends beyond the body to be exposed and operable directly by a user. A preferably enlarged head end provides a large gripping surface for such operation. A preferred embodiment further includes a recess or locally wide portion in the slot into which the pin is selectively held. A recess corresponds to each pivot position of the jaws. In the above example therefore with two jaw pivot positions there would be two recesses or sets of recesses. Optionally the pin may be located on the upper jaw while the lower jaw is moved in relation to the upper jaw. In this case the slot may be within or upon the lower jaw.
One feature of the invention is a compact spring assembly to provide both a reliable detent bias and a firm rotational bias to a lower jaw. The pin is spring biased in the detent action into the recess but not normally mechanically locked in position. A user operates directly on the pin to move it out of the recess and along the slot. As discussed in detail below normal gripping or clamping with the pliers adds further biasing force to retain the pin in the recess. In this manner no further locking elements are needed to securely position the pin although such features may optionally be added if desired. Therefore the pivot position may be adjusted without secondary releasing steps. Further the adjustment process is immediate and intuitive since moving the pin directly moves the lower jaw in the preferred embodiment. This contrasts with some known designs where a handle or other indirectly related element must be manipulated before the jaw size can be adjusted. With the lower jaw also biased by the spring assembly to rotate away from the upper jaw the handle is biased away from the body as a user holds the tool in its pre-locking condition about a work piece. The pliers thereby gives feedback for the handle position as the handle moves within the hand grip before it is locked.
In the illustrated embodiment the features of the invention are provided in a familiar locking pliers configuration. It is an object of the invention that the design be familiar whereby the additional features and functions of the invention are readily understood and usable while adding no or minimal additional bulk to the device. In contrast many prior pliers are complex in appearance and in fact without even offering the new advantages of the present invention. It is a feature of the invention that the new function is provided with the addition of only a simple wire formed part and optionally a washer to the known locking pliers device. A novel way to attach and link simple components provides an unexpected result of the invention. Other novel but visually simple features are included in the structure of the invention. The pliers of the invention can therefore be manufactured inexpensively and without great investment in tooling.
Alternately it may be desired to incorporate the features of the invention into a pliers or clamping device that is of other familiar or less familiar forms. The jaws may be of various forms. In the illustrated embodiment the jaws are a straight serrated style for demonstrative purposes. Other known jaw configurations for example are smooth, needle nose, concave, or c-clamp style. Other jaw configurations are anticipated as usable with the pliers of the invention. In one example if the jaw adjusting motion is sufficiently large the device may take more the form of a bar clamp rather than a pliers. In this example a slot or recess may extend along a bar to selectively fit the pivot pin described herein. Or for example the invention may be used in a pliers that more resembles a water pump pliers type configuration. Preferably but not exclusively the pliers of the invention is a locking type, although a non-locking type will also benefit from the present invention. For example a pliers without the over-center action would be a non-locking type.
Knob 90 enables rotation of screw 91, threads not shown, within a threaded opening of body 10. Lower jaw 40 rotates about pin 70 where pin 70 is held in recess 15a of slot 15. When handle 20 is moved toward body 10 linkage 30 moves past a center position. If screw 91 is properly adjusted the over center action occurs as jaws 40 and 50 fit about a work piece. Optionally the features of the invention may be used to improve an automatic adjusting locking or non locking pliers. In this case screw 91 or other appropriate feature is replaced or supplemented with an auto sizing mechanism of known type. Body 10 is preferably elongated from upper jaw 50 toward a rear end of the body to provide a hand grip surface on the body.
When handle 20 is moved away from body 10 the jaws move apart to an open position as or similar to that shown in
According to the invention the pliers include at least two distinct size ranges. This feature is readily apparent by comparing
It is desirable to maintain a similar jaw angle between selected size ranges for a given position of screw 91. This helps the usage of the pliers to be more predictable and intuitive. As seen between
Recesses 15 and 15b preferably extend forward from slot 15 as shown. Preferably body 10 is of sheet metal form and slot 15 comprises two corresponding slots in opposed sides of the body. Pin 70 is biased into these recesses in a similar force direction both for loaded and unloaded conditions. Therefore pin 70 normally maintains a same position in a recess or equivalent structure as the pliers transition between loaded and unloaded conditions, for example as gripping force begins to bear upon a work piece. This constant pivot position helps to keep the jaw action simple and predictable. The loaded condition includes the jaws being pressed against each other either directly as in
In the loaded condition linkage 30 provides a forward force upon handle 20 at front link pivot 22. This force is relative to body 10 as screw 91 presses the link forward. At connection 41 handle 20 pivotally connects to lower jaw 40. Handle 20 transmits its forward force to lower jaw 40 at the connection. Therefore there is a net forward force upon lower jaw 40 relative to body 10. This forward or lateral detent force urges pin 70 into recess 15a or 15b. Pin 70 is attached to jaw 40 at hole 46,
As just described for the jaw loaded condition the pliers assembly is inherently stable with respect to any selected position of pin 70. Force F is proportionate to the gripping force so the pliers are more stable as the gripping force of the jaws increases. As further described below the assembly is also stable when it is manipulated without a load. For example pin 70 remains in its selected position as handle 20 and screw 91 are moved and adjusted to position the jaws about a work piece. However pin 70 can readily be moved between selected positions when desired.
For the jaw unloaded condition the force from spring 60 is used to maintain a stable selected position for pin 70. Both a small size range and a large size range have a stable position for pin 70 in an unloaded condition. Spring 60 pulls rearward upon lower jaw 40 at spring hook 68 at a front end of the spring in opening 47. This force creates a firm bias to open lower jaw 40 and handle 20 as handle 20 is moved away from body 10. According to a preferred embodiment of the invention the rear end of spring 60, at hook 69, does not directly link to body 10 as is typical in prior locking pliers. Rather the immediate connection of hook 69 is to wire link 65,
Preferably wire link 65 includes a free position with the hook of one end in the open position 66a,
The rear of wire link 65, along with spring hook 69, is slidably held in body 10 by tabs 11,
Optionally further arms, springs, or other members may hold wire link 65 in position relative to body 10. For example if components beyond tabs 11 are configured or added to cause an upward bias upon the rear of wire link 65 then tabs 11 will not be required. In another alternate embodiment, not shown, a second spring may push upon lower jaw 40 at or near opening 42 or equivalent location. This second spring may replace or supplement wire link 65 to form the spring assembly with spring 60. Then one or both springs may attach to a fixed location of body 10, for example near to tab 11. The function will normally be equivalent to the use of rigid wire link 65 with a possible trade off in complexity. A further option below includes a torsion spring.
As just described for the unloaded condition lower jaw 40 is pulled rearward at its bottom and pushed forward at its top to create a torque on the lower jaw. The pulling is at opening 47 and the pushing at opening 42. These respective locations are substantially spaced apart from each other to create a firm rotational torque on lower jaw 40 relative to handle 20. Specifically lower jaw 40 is biased to rotate counter clockwise away from upper jaw 50 about connection 41 in the views. Pin 70 is held in hole 46 of the jaw. Therefore pin 70 is pressed forward in slot 15; see
A firm rotational bias according to the invention is sufficient to cause handle 20 to reliably move against a predetermined force for a substantial majority of the possible motion of the handle in an unloaded condition. A further way to consider a firm torque is that which is sufficient to hold the handle in an open position against a predetermined force. Such a predetermined force may be the weight of handle 20 and its linked elements. For example if the views of
Alternately the firm rotation bias may be indirectly applied to the lower jaw. For example the bias may be directly upon the handle by a further spring connecting the handle to the jaw, the body or other element of the pliers, not shown. For example a torsion spring may be fitted at the pivot of opening 41 to bias lower jaw 40 and handle 20 toward the respective open positions. In this example the lower jaw is biased to rotate by way of the handle at opening 41.
Through the rotational bias or equivalent force pin 70 is pressed into the recess by a force in relation to handle 20. As discussed above handle 20 may be pressed forward in relation to body 10 through link 30, so pin 70 is pressed into the recess by a force also in relation to body 10. The unloaded force upon pin 70 from spring 60 is in a similar direction to loaded force F discussed above and in fact is normally additive to the force F, although of lesser magnitude. Therefore the applied force upon pin 70 holds the pin without shifting or otherwise substantially moving the pin in a selected recess through a transition between loaded and unloaded conditions.
It is desirable that lower jaw 40 be firmly biased to move toward its pivoted open position for any condition of the pliers other than locked as discussed above. This pivoting bias is preferably relatively constant for all rotational jaw positions, although the resulting bias on handle 20 will be non-linear because of the varying force inherent in the over-center connection to the handle. Specifically the force moving handle 20 away from body 10 will be less as link end 32, link pivot 22, and opening 42 are near aligned in the on-center or locked condition of these elements. In the respective aligned positions of
Comparing
As discussed above the respective pushing and pulling forces are spaced apart. Opening 42 is biased forward near to pin 70 in all size range positions, compare
In the preferred illustrated embodiment wire link 65 or equivalent structure is an elongated narrow element that is co-extensive with the interior of body 10. An alternate embodiment biasing spring is shown in
According to this alternate embodiment lower jaw 40 may be provided both an opening and a forward bias by a single spring element. No further link is required. This contrasts with a biasing spring known in the art wherein a torsion spring includes only a single coil remote from the lower jaw and can provide only a forward bias on a single location of the lower jaw. As a result the prior jaw and handle are limp with no opening bias upon the handle. In a further option a compression or extension spring, not shown, may be fitted to or extend along arm 165 to provide the forward bias. As illustrated the first coil 162 is mounted near a separate pin or equivalent structure spaced from pivot pin 70. This allows the torsion coil to be fitted at a narrow extension of lower jaw 40 whereby the pliers can remain slim at the area of pivot pin 70. Optionally coil 162 may be fitted at or around pin 70.
In the preferred or alternate embodiment biasing spring designs a spring, combination of springs, or operative rigid links to the springs may be described as a spring assembly. The spring assembly provides a dual force action to the lower jaw. This force comprises both a forward bias at the pivot pin and a torque to the lower jaw. To benefit from the advantage of the invention the torque must be high enough to create the firm opening bias to the handle of predetermined force discussed above.
As illustrated the front side of slot 15 includes recess 15a and 15b. The spring bias upon pin 70 described here is a primary positioning force for any unloaded condition of the pliers. For example it operates in
To select a position for pin 70 in slot 15, and a resulting size range for the pliers, the pin may be moved directly by a user's fingers. Enlarged head 71,
When moved rearward out of a recess pin 70 will normally be biased to slide along a front side of slot 15 to move toward the upper recess, recess 15a in the instant example. This is a result of the angle of spring 60 relative to slot 15 or body 10 wherein the spring pulls upward on lower jaw 40. This creates a default position of the small or “normal” size range of
It is possible that the pliers may be accidentally dropped. If this occurs in the unloaded condition of
Optionally as described later herein a secondary action may be added to pin 70 or equivalent structure to positively lock it in position, although such secondary feature is not required. When loaded as described earlier pin 70 is held very securely wherein force F is a primary feature. In the loaded case the pliers will be more resistant from moving out of any recess of slot 15 when dropped or impacted.
Optionally spring 60 may be configured to minimize or remove the default position bias, or to make the larger size range a default position. For example spring 60 may be mounted at a different angle or further arms or springs may be linked to lower jaw 40 or other components, not shown. Then, for example, pin 70 will have no bias to move vertically along slot 15. Or the pin may be biased to move toward lower recess 15b.
In
Pin 70 may be initially formed with a single head. The opposing head may be in the form of a washer that is riveted or swaged against a shoulder, not shown, of the opposed small pin end after assembly to the pliers. Or the opposed head may be entirely formed from the small end by a riveting operation. An advantage of the washer structure is that the shoulder defines a relatively precise position for the second head. Then the pin can be fitted about body 10 with the slight spacing of the head inside faces while ensuring that the pin will not bind upon body 10. Optionally pin 70 is a direct extension of lower jaw 40 wherein there may be no explicit separate pin 70 nor hole 46 into which the pin is fitted. Optionally pin 70 may have a minimal head.
A further method of selecting a size range provides that a user moves lower jaw 40 directly rather than by pin 70 to cause pin 70 to translate in slot 15 or equivalent structure. However this may be less intuitive since it is more common to operate a button type structure, i.e. the head of pin 70, and further when lower jaw 40 is near to upper jaw 50 it will be difficult to grasp the lower jaw to manipulate it. The spring assembly is resilient such that the rotational bias is firm while the detent bias may be light. The dual action spring assembly efficiently separates the two functions so that for example a very high detent force is not required to generate a firm rotation bias. In the preferred embodiment the pushing and pulling force application locations are spaced well apart so that a firm pulling at opening 47 to create the rotating bias does not affect the pushing bias at opening 42. Alternately a torsion spring proximate to pin 70 creates an independent rotational bias, whereby the torsion spring is biased forward by a further element of the spring assembly. With a preferably light detent bias the slide switch created at head 71 is operable by a single finger on a single side of the body 10. Thus the size range may be readily selected by a same single hand that holds the pliers. Optionally both head ends of pin 70 may be operated.
The simple structure of pin 70 requires no secondary elements to move pin 70 to, or hold the pin in, a selected recess or equivalent stable location of body 10. Therefore no such elements need be actuated to enable moving lower jaw 40. With no need for such additional elements or motions pin 70 normally remains in a constant position and orientation relative to lower jaw 40 as the pin moves along with the jaw as the size range is adjusted. However if desired secondary motions of pin 70 or associated elements relative to lower jaw 40 may be enabled, for example, as a supplemental locking structure or other reasons. Further lower jaw 40 need not be rotated for the purpose of size selection.
As illustrated there are two recesses in slot 15. Optionally more than two may be included. The recesses are preferably rounded or smooth as shown. Optionally they may include flats with a pointed inside corner for example in the form of a notch in the front of slot 15. Further there may be a recess or notch in a rear of slot 15 to correspond or supplement the front recesses shown. In a further embodiment pin 70 may be oblong, D shaped in section, or other non-round shape and be rotatable. Then the pin may include a further operating mode, not shown, that rotates the pin between a secure mode in a recess and a movable mode that allows the pin to slide between recesses. Or the pin may be or include an element that is movable axially. These secondarily movable pins may engage only a front recess or both a front and rear recess. Such structures may be desired for example to make changes in size range less convenient or to more positively hold a selected size range. However as discussed earlier the pliers in the illustrated embodiment is normally stable in both unloaded and loaded conditions.
It is a feature of the invention that the headed version of pin 70 illustrated is of a familiar appearance being minimally or no larger than a rivet in a similar location of a conventional one-sized device. Pin 70 may be compact because it does not require any secondary function. For example pin 70 does not need to be depressed, moved axially, or rotated to release jaw 40 to move to another size range. Rather pin 70 is stable in a selected position through the further structures described herein.
In the present invention a pliers is improved at minimal cost. In the preferred embodiment only a simple wire form, wire link 65, need be added. A second optional component is the washer head discussed for pin 70. Prior size range adjusting locking or similar pliers required complex or bulky assemblies to provide the adjusting function or were difficult to operate. The simplicity of the inventive structure includes a novel linkage between a spring and a lower jaw. The components of the pliers may be manufactured in a same manner as known pliers so that there is no additional cost to such components. For example lower jaw 40 and body 10 have no added complexity over conventional respective parts. This simple structure provides a novel function in a familiar, compact and intuitive pliers device.
According to the invention a selected size range is held as a stable condition for both loaded and unloaded states. In particular, in the preferred embodiment unloaded state, a pivot pin such as pin 70 includes a button type feature and moves to or from a selected size range with no secondary actions upon or by the pin. For example the pin may be rigidly attached to lower jaw 40 where the pin moves directly with the jaw and is directly operated upon by a user in an action similar to moving a slide switch. Optionally the pin may rotate within an opening of the jaw but need not require such rotation to allow jaw 40 to move to a different size range. To maintain a stable selected size range a spring, spring element or resilient element biases pin 70 and/or jaw 40 into a detent or equivalent engagement to slot 15 or equivalent structure. For example as pin 70 slides along slot 15 the pin will snap forward into a selected recess from the bias force of spring 60 when the pin becomes aligned with the recess. In a preferred embodiment the spring forces are spaced apart on the lower jaw to maintain a firm opening bias upon the lower jaw for all freely movable positions of the pliers. For example the spring as able to firmly pivot the lower jaw from its closed, unloaded, position to its most open position for any selected size range.
In contrast to the present invention prior auto adjusting pliers have required the pin, an attached handle, or a further lever, to be rotated or translated to enable moving between size ranges. Or a pin required an axial pressing motion for such movement. In certain prior auto-adjusting pliers an unloaded condition is unstable in at least one direction. For example a lower jaw maybe biased to remain in a maximum position of a size range but still be immediately and unpredictably movable toward a smaller position with only the spring bias and incidental friction resisting this upward motion. In other prior locking pliers a detent biasing spring can provide only that single function, where the lower jaw and handle are limp in all unloaded positions. According to the present invention a single spring can hold the jaws to a selected size range in a predictable and repeatable manner including for example either a small or a large size range. The same spring may provide the further functions required to facilitate operating as a locking or similar pliers once the size range is selected, including the function of providing a firm opening bias to the handle through most possible handle positions. The opening bias may be through the lower jaw as illustrated or directly upon the handle by a further spring connecting the handle to the jaw or the body, not shown. To adjust the jaw the jaw or an attached pin is moved directly by a user to the selected position without secondary rotation or other actions. The lower jaw may maintain a constant angle relative to the upper jaw as the position of pin 70 is moved to a selected size range.
While particular forms of the invention have been described and illustrated, it will be apparent to those skilled in the art that various modifications can be made without departing form the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited except by the appended claims.
