EP2301119B1

EP2301119B1 - Cord protector for power tools

Info

Publication number: EP2301119B1
Application number: EP20090774227
Authority: EP
Inventors: Warren A. Ceroll; Daniel Puzio; Robert S. Gehret; Richard C. Nickels; James R. Parks; Scott Rudolph; Robert J. Opsitos
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2008-06-30
Filing date: 2009-06-29
Publication date: 2015-05-13
Anticipated expiration: 2029-06-29
Also published as: EP2301119A2; CN102113185B; JP2011527081A; WO2010002776A2; EP2301119A4; WO2010002776A3; CN102113185A

Description

FIELD

The present disclosure relates to various improvements for power tools, and particularly to a cord set load protector.

BACKGROUND AND SUMMARY

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A common field failure with heavier portable power tools, such as portable saws, is a separation of the power cord from the tool due to an impulse load, or jerk, applied to the cord. This can occur when the tool is dropped while the plug end of the power cord is secured, or when a user carries the tool or lowers it from floor to floor or down a ladder by holding the power cord. It has been proposed in our earlier patent US 2,496,612 to enable a power tool to be carried by its power cord by providing a strap connected to the cord and the power tool, to allow a certain amount of slack in the cord near the tool. US 6,152,639 discloses an arrangement which limits rotation of the power cord near the tool to allow use of the tool at different orientations by clamping the cord in a housing at the base of the tool, which housing is capable of a certain amount of pivotal movement. DE 43 44 635 discloses a cord protector having a sleeve to resist bending of the cord over the region where it enters the power tool, the sleeve being mounted at one end in a ball rotatable in a socket in the tool housing to allow the tool to be used at different orientations. A guide is provided in the housing to control any movement of the cord as a result of this pivotal movement.
The invention provides a power tool as defined in the appended claims.
The spring lever member serves to isolate the power cord conductors or connections from the high forces imposed by jerking the power cord. The power cord is may be installed in the tool housing with a small service loop, or extra length of cable, between the cord clamp and the portion of the tool housing that secures the cord protector. A crimp-on device may be installed on the power cord cable next to the cord protector. When the cord is subjected to jerking, the cable moves axially relative to the cord protector. As the cable moves, the crimp-on device compresses the extended end of the cord protector absorbing energy and reducing the forces transmitted to the cord set conductors or connections that are disposed within the housing.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

Figure 1 is a perspective view of an exemplary worm drive saw with a tool hanger according to the principles of the present disclosure;
Figure 2 is a cross-sectional view showing the cord set load protector according to the principles of the present disclosure, in an unloaded condition;
Figure 3 is a view similar to Figure 2 with a load applied to the cord;
Figure 4 is a perspective view of an exemplary cord clamp utilized with the cord set load protector according to the principles of the present disclosure;
Figure 5 is a perspective view of a first clamp half;
Figure 6 is a perspective view of a second clamp half;
Figure 7 is a perspective view of a cord set load protector design with the handle partially removed for illustrative purposes according to some embodiments;
Figure 8 is a perspective view of a cord set load protector design according to some embodiments having a serpentine pattern;
Figure 9 is a front view of the cord set load protector design according to Figure 8 in an initial position;
Figure 10 is a front view of the cord set load protector design according to Figure 8 in a deflected position;
Figure 11 is a perspective view of a cord set load protector design according to some embodiments having an engagement plate;
Figure 12 is a front view of the cord set load protector design according to Figure 11 in an initial position;
Figure 13 is a front view of the cord set load protector design according to Figure 11 in a deflected position;
Figure 14 is a front view of the cord set load protector design in an initial position according to some embodiments having an engagement plate;
Figure 15 is a front view of the cord set load protector design according to Figure 14 in a deflected position;
Figure 16 is a perspective view of a cord set load protector design according to some embodiments having inwardly positioned biasing members;
Figure 17 is a front view of the cord set load protector design according to Figure 16 in an initial position;
Figure 18 is a front view of the cord set load protector design according to Figure 16 in a deflected position;
Figure 19 is a front view of the cord set load protector design in an initial position according to some embodiments;
Figure 20 is a front view of the cord set load protector design according to Figure 19 in a deflected position;
Figure 21 is a front view of the cord set load protector design in an initial position according to some embodiments;
Figure 22 is a front view of the cord set load protector design according to Figure 21 in a deflected position;
Figure 23 is a front view of the cord set load protector design in an initial position according to some embodiments having extension springs;
Figure 24 is a front view of the cord set load protector design according to Figure 23 in a deflected position;
Figure 25 is a front view of the cord set load protector design in an initial position according to some embodiments having extension springs;
Figure 26 is a front view of the cord set load protector design according to Figure 25 in a deflected position;
Figure 27 is a front view of the cord set load protector design in an initial position according to some embodiments having a leaf spring;
Figure 28 is a front view of the cord set load protector design according to Figure 27 in a deflected position;
Figure 29 is a front view of the cord set load protector design in an initial position according to some embodiments having a torsion spring;
Figure 30 is a front view of the cord set load protector design according to Figure 29 in a deflected position;
Figure 31 is an enlarged perspective view of the biasing member of Figure 29;
Figure 32 is a front view of the cord set load protector design in an initial position according to some embodiments having a tether system;
Figure 33 is a front view of the cord set load protector design according to Figure 32 in a deflected position;
Figure 34 is a front view of the cord set load protector design in an initial position according to some embodiments having a piston device;
Figure 35 is a front view of the cord set load protector design according to Figure 34 in a deflected position;
Figure 36 is a front view of the cord set load protector design in an initial position according to some embodiments having a piston device and orifice channels; and
Figure 37 is a front view of the cord set load protector design according to Figure 36 in a deflected position.
Figure 38 is a front view of the cord set load protector design in an initial position according to some embodiments having a spring lever;
Figure 39 is a front view of the cord set load protector design according to Figure 38 in a deflected position;
Figure 40 is a front view of the cord set load protector design in an initial position according to some embodiments having a spring lever and supplemental spring;
Figure 41 is a front view of the cord set load protector design according to Figure 40 in a deflected position;
Figure 42 is a front view of the cord set load protector design in an initial position according to some embodiments having a spring lever and torsion spring;
Figure 43 is a front view of the cord set load protector design according to Figure 42 in a deflected position;
Figure 44 is a perspective view of a cord set load protector design according to some embodiments having a spring lever and cord clamp;
Figure 45 is a perspective view of the spring lever;
Figure 46 is a perspective view of cord clamp;
Figure 47 is a front view of the cord set load protector design in an initial position according to some embodiments having a spring member; and
Figure 48 is a front view of the cord set load protector design according to Figure 47 in a deflected position.
Figure 49 is a front view of the cord set load protector design in an initial position according to some embodiments having a biasing media;
Figure 50 is a front view of the cord set load protector design according to Figure 49 in a deflected position;
Figure 51 is a front view of the cord set load protector design in an initial position according to some embodiments having a coil spring;
Figure 52 is a front view of the cord set load protector design according to Figure 51 in a deflected position;
Figure 53 is a front view of the cord set load protector design in an initial position according to some embodiments having a spring lever;
Figure 54 is a front view of the cord set load protector design according to Figure 53 in a deflected position;
Figure 55 is a front view of the cord set load protector design in an initial position according to some embodiments having a breakaway connection;
Figure 56 is a front view of the cord set load protector design according to Figure 55 in a deflected position;
Figure 57 is a perspective view of a cord set load protector design according to some embodiments having a cam follower;
Figure 58 is a front view of the cord set load protector design according to Figure 57 in an initial position;
Figure 59 is a front view of the cord set load protector design according to Figure 57 in a deflected position;
Figure 60 is a perspective view of a cord set load protector design according to some embodiments having a cam follower in an initial position; and
Figure 61 is a perspective view of the cord set load protector design of Figure 60 in a deflected position.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
With reference to Figures 1 and 2, an exemplary power tool 10 is shown having a cord set load protector device 114 for preventing high forces imposed on a power cord 112 from impacting the connections of the cord 112 to the electrical power tool 10. As illustrated in Figure 1, the power tool 10 includes a cord 112 and a cord protector 114 extending from the rear end of the tool. The cord protector 114 is mounted within a recess 116 provided in the power tool housing 118. The recess 116 can be square or round in cross-section and defines a cavity therein for receiving a radially extending flange portion 120 of the elastomeric cord protector 114. The radial extending flange portion 120 is disposed against a shoulder portion 122. A crimp-on device 124 is clamped or crimped onto the power cord 112 and includes a radially extending flange portion 126 which is disposed against an end portion of the cord protector 114 inside of the chamber 116 of housing 118. The flange portion 126 is disposed against a radially inwardly extending shoulder 128 of the cavity 116 provided in the housing 118.
The crimp-on device 124 engages the power cord so as to be axially and rotatably fixed to the power cord 112 in a manner that will be described in greater detail herein. The power cord 112 is also clamped to the tool housing by a cord clamp 130 provided within the power tool 10 in such a way that an extra cable length 112a is provided within the housing between the crimp-on device 124 and cord clamp 130. The cord clamp 130 can be mounted to the housing by fasteners 132 or by other known securing methods, such as rivets, welds, grommets, etc. The cord clamp 130 can be spaced from the recess 116 by up to several inches. Locating the cord clamp 130 further inward from the recess 116 improves cord flex durability by placing the cord stresses from the cord being flexed and the stresses on the cord due to the clamp at two different locations instead of both being generally at the same location. This improves the flex life of the conductors.
When a large force F is applied to the power cord 112, as illustrated in Figure 3, the power cord 112 is pulled in the axial direction of the force F. The movement of the power cord 112 relative to the housing 118 causes the crimp-on device 124 to move axially relative to the shoulder portion 128 so that the flange portion 126 of crimp-on device 124 compresses the flange portion 120 of cord protector 114, thereby absorbing the force exerted on the cord 112. The axial movement of the crimp-on device relative to the cord clamp 130 takes up some of the extra cable length 112a provided therebetween without exerting forces upon the cord clamp 130.
The crimp-on device 124 can take-on many forms. By way of example, as illustrated in Figures 4 and 6, the crimp-on device 124 can include a first clamp half 136 and a second clamp half 138. Each clamp half 136, 138 is provided with semi-cylindrical body portions 140 each provided with a plurality of radially inwardly extending ribs 142 designed to engage and clamp against the outer surface of the power cord 112. The first clamp half 136 is provided with a plurality of apertures 144 each adapted to receive a plurality of corresponding locking fingers 146 provided on the second clamp half 138. Each of the first and second clamp halves 136, 138 include radial flange portions 126a, 126b, respectively, which define the radially extending flange portion 126 of the crimp-on device 124. The locking fingers 146 secure the second clamp half 138 to the first clamp half 136 in a clamping engagement on the power cord 112 so as to prevent axial or rotational movement of the power cord 112 relative to the clamp device 124. It should be understood that other clamp or crimp-on arrangements can be utilized with the cord-set load protector 110, according to the principles of the present disclosure.
With reference to Figure 7, an alternative cord set load protector 110' is shown including a split clamp device 124' received in a recess 302 within the handle section 300 to prevent the assembly from twisting or being pushed into the handle set. The split clamp 124' is independent of the handle set 300 and traps the complete cord set 112 and secondary wrap of filler strands. The cord protector 114' includes added material at the mounting end that prevents twist and creates a spring to absorb shock.
In some embodiments, as illustrated in Figures 8-10, cord set load protector 110 can comprise a plurality of biasing members, such as ribs, posts, and/or springs, extending within the housing to provide, at least in part, shock absorbing function. Specifically, housing 118 can comprise two or more biasing members 402 extending inwardly from housing 118 (such as three biasing members 402 as illustrated). A longitudinal axis of each of biasing members 402 can be orthogonal to power cord 112 prior to deflection of biasing members 402. Biasing members 402 can be arranged to provide a serpentine routing of power cord 112 through housing 118. Although it should be appreciated that other routing configurations can be used within the scope of the present teachings. More particularly, as illustrated in Figure 9, biasing members 402 can be arranged such that each is offset laterally relative to an axis PC. The exact amount of this offset can be determined based upon the compliancy desired in cord set load protector 110, characteristics of power cord 112, and the physical properties of biasing members 402.
It should be appreciated that biasing members/spring lever 402 can include features, materials, or employ other manufacturing techniques directed to tailoring a compliant response when under load (i.e. a biasing profile). For instance, in some embodiments, biasing members/spring lever 402 can comprise a molded or formed member having a cross-sectional shape that is non-cylindrical, such as tapered, notched, planar and/or non-uniform. This cross-sectional shape can provide a non-linear compliant response when under load to permit initial deflection under light loads and progressively less deflection under heavier loads.
Furthermore, with continued reference to Figures 8-10, in some embodiments, biasing members 402 of cord set load protector 110 can be sized and made of material to provide a predetermined compliancy. For instance, biasing members 402 can have a diameter sufficient to enable elastic deformation. Similarly, biasing members 402 can be made of a material that enables such elastic deformation. Still further, a combination of sizes and materials can be provided to achieve such elastic deformation. Additionally, biasing members 402 can be integrally formed with housing 118 with a similar material as housing 118 or with a differing material.
During use, if sufficient force is applied to power cord 112, the associated force is transmitted against biasing members 402 to deflect biasing members 402 in a direction such that a degree of the serpentine shape is reduced (see progressive steps of Figures 9 (undeflected) and 10 (deflected)). This deflection provides force absorption along axis PC.
With reference to Figures 23-26, it should be appreciated that biasing members 402 can comprise spring members operably engaging power cord 112 to provide a biasing force causing power cord 112 to deflect into a serpentine configuration. In such embodiments, biasing member 402, comprising a spring member, can be coupled at one end to housing 118 or other retaining structure 408 and at the other end to a rotatable pulley 404 (Figures 25 an 26) or engagement member 406 (Figure 23 and 24). Rotatable pulley 404 can be used to facilitate non-binding translation of power cord 112 relative to biasing member 402. When such translation of power cord 112 is minimal, engagement member 406 can be used. Biasing members 402, comprising spring members, can include varying spring rates relative to each other to enhance or tailor a desired biasing profile.
In some embodiments, as illustrated in Figures 11-15, biasing members 402 can be ribs extending inwardly from opposing sides of housing 118 and can be configured to engage an engagement plate 410 fixedly coupled to power cord 112 for movement therewith. More particularly, engagement plate 410 can comprise a circular disk having an aperture 412 sized to receive power cord 112 there through. Engagement plate 410 can be retained in position relative to power cord 112 via an abutment clamp 414. In some embodiments, abutment clamp 414 can include a U-shaped main member 416, a backside retaining plate 418, and a plurality of fasteners 420 for clampingly coupling U-shaped main member 416 and backside retaining plate 418 about power cord 112 for movement therewith. It should be appreciated that U-shaped main member 416 can be sized to define an interference fit with power cord 112 when abutment clamp 414 is mounted thereto. It should also be appreciated that alternative abutment clamps or retaining members can be used. It should also be appreciated that engagement plate 410 and abutment clamp 414 can be formed of a single, integral member and can have a variety of shapes found to be properly engagable with biasing members 402.
Still referring to Figures 11-15, it can be seen that biasing members 402 can be formed as a series of ribs having planes generally orthogonal to power cord 112. Biasing members 402 can be arranged on opposing sides of power cord 112, or circumferentially about power cord 112, to apply a balanced cord protection force. As described herein, biasing members 402 of cord set load protector 110 can be sized and made of material(s) to provide a predetermined compliancy. For instance, biasing members 402 can have a constant thickness, a varying thickness along its length, a varying thickness relative to other biasing members, be made of a compliant material, or a combination of these properties to enable elastic deformation along a predetermined biasing profile. Additionally, biasing members 402 can be arranged relative to each other such that a first of the biasing members 402 is deflected and engages a second of the biasing members 402 (and so on) to provide a compounding biasing force.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating engagement plate 410 and abutment clamp 414 to the left in the figures. This translation causes engagement plate 410 to engage the series of biasing members 402 in succession and thus the associated force is transmitted against biasing members 402 to deflect biasing members 402. This deflection provides force absorption along axis PC.
In some embodiments, as illustrated in Figures 14 and 15, abutment clamp 414 can comprise an elongated member coupled to power cord 112 for movement therewith. In this embodiment, abutment clamp 414 can comprise a series of circumferential slots 422 sized to receive respective ends of biasing members 402 therein. In this way, each of the plurality of biasing members 402 can simultaneously be actuated or deflected upon initial movement of power cord 102 along axis PC, thereby providing a generally linear biasing response. Abutment clamp 414 can be made of a flexible or elastomeric material to provide biasing relative to biasing members 402, as is illustrated in Figure 15.
In some embodiments, as illustrated, in Figures 16-18, biasing members 402 can be ribs extending inwardly from opposing sides of housing 118 and can be positioned within a center portion of a loop formed in power cord 112. That is, biasing members 402 can be formed as two or more ribs around which power cord 112 can pass. Biasing members 402 can have an arcuate shape closely conforming to a predetermined loop radius of power cord 112. It should be appreciated that the loop radius should be selected so as not to overly strain power cord 112.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby exerting an inwardly directed compression force on biasing members 402 causing biasing members 402 to deflect from a first position (Figure 17) to a second position (Figure 18). This deflection provides force absorption along axis PC.
Referring now to Figures 19-22, in some embodiments, biasing member 402 can comprise a member formed separate from housing 118, such as a spring steel ring (Figures 19 and 20), an elastomeric or compressible member (Figures 21 and 22), a hollow sealed member, or other energy absorbing member. In such embodiments, biasing member 402 can be positioned to an inner corner of housing 118 such that when force is applied to power cord 112, such force is translated to biasing member 402, thereby compressing biasing member 402 against a sidewall of housing 118. In some embodiments, housing 118 can comprise a contour 420 for receiving biasing member 402 therein and retaining biasing member 402 in a predetermined position. It should be appreciated that biasing member 402 can be made of any material that provides sufficient elastic/compliant properties, such as spring steel, elastomers, and the like.
Turning now to Figures 27 and 28, in some embodiments, biasing member 402 can comprise a leaf spring 430. Leaf spring 430 can include a generally arcuate member being made of material sufficient to elastically deflect and provide a biasing force to power cord 112. In some embodiments, leaf spring 430 is retained on opposing ends 432 by retaining members 434. Retaining members 434 can be fixedly coupled to housing 118. It should be appreciated that in some embodiments retaining members 434 can be sized to permit free slidable movement of leaf spring 430 relative thereto (see Figure 28).
During use, if sufficient force is applied to power cord 112, power cord 112 is straightened thereby exerting an upwardly directed force on biasing members 402 causing leaf spring 430 to deflect from a first position (Figure 27) to a second position (Figure 28). This deflection provides force absorption along axis PC.
Turning now to Figures 29-31, in some embodiments, biasing member 402 can comprise a torsion spring member 436. In some embodiments, torsion spring member 436 includes a torsion spring 437 that is retained on one end 438 by retaining members 444. Retaining members 440 can be fixedly coupled to housing 118. Torsion spring member 436 can comprise a slot portion 442 formed therein for receiving and retaining power cord 112.
During use, if sufficient force is applied to power cord 112, power cord 112 is straightened thereby exerting an torsion force on biasing members 402 causing torsion spring member 436 to rotate counter-clockwise in the figures against the biasing force of torsion spring 437 from a first position
(Figure 29) to a second position (Figure 30). This deflection provides force absorption along axis PC.
With reference to Figures 32 and 33, in some embodiments, biasing member 402 can comprise a biased tether system 450. Biased tether system 450 can comprise a biasing reel 452 retaining a tether 454. Tether 454 can comprise a coupler member 456 fixedly coupled to power cord 112. Biased tether system can be disposed such that at least a portion of thereof extends outside of housing 118. In such embodiments, an aperture 458 is formed in housing 118 to permit tether 454 to pass therethrough.
Biasing reel 452 can be spring biased to provide a retracting force on power cord 112. In this regard, during use, if sufficient force is applied to power cord 112, power cord 112 is straightened thereby exerting a force on tether 454 which is transmitted to biasing reel 452. Such force caused biasing reel 452 to rotate clockwise in the figures against the biasing force thereof from a first position (Figure 32) to a second position (Figure 33). This deflection provides force absorption along axis PC.
Referring now to Figures 34 and 35, in some embodiments, biasing member 402 can comprise a piston device 510 to provide, at least in part, shock absorbing function. Specifically, in some embodiments, piston device 510 can be disposed within housing 118 or, in some embodiments, can be formed outside of housing 118. With particular reference to Figures 34 and 35, piston device 510 can comprise a piston member 512 slidably disposed within a piston chamber 514. Piston member 512 can define a seal between piston member 512 and piston chamber 514 to create a compressible pressure volume 516. Piston member 512 can comprise a rod 518 fixedly coupled to a cord clamp 130, which in turn is fixedly coupled to power cord 112 for movement therewith. Piston chamber 514 can be fixedly coupled to housing 118 or integrally formed therewith. In some embodiments, piston chamber 514 can be retained by a retainer structure (not shown) separate from housing 118.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating piston member 512 relative to piston chamber 514 to the left in the figures. This translation causes piston member 512 to compress a fluid, such as air, gas, or liquid, within pressure chamber 516 thereby creating an opposing biasing force. This compression of fluid within pressure chamber 516 provides force absorption along axis PC at an increasing rate.
Turning now to Figures 36 and 37, in some embodiments, piston device 510 can be disposed within housing 118 such that piston member 512 slidably engages piston chamber 514. Piston chamber 514 can be formed as part of housing 118 such that piston member 512 slidably engages an inner wall of housing 118 to form a seal therewith and define compressible pressure volume 516. Piston member 512 can be directly, fixedly coupled to power cord 112 for movement therewith. In some embodiments, piston member 512 can comprise one or more orifice channels 530 extending therethrough. Orifice channels 530 can provide a regulated flow of fluid (i.e. air) from compressible pressure volume 516 to atmosphere. In other words, orifice channels 530 can be sized to permit a predetermine rate of fluid evacuation to produce a desired biasing profile. In some embodiments, an orifice plate 532 can be disposed in housing 118, engaging retaining features 534 formed in housing 118, to define compressible pressure volume 516. Orifice plate 532 can comprise one or more orifice channels 530 formed therethrough to further enhance and tailor regulated flow of fluid (i.e. air) to and from compressible pressure volume 516
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating piston member 512 relative to piston chamber 514 to the left in the figures. This translation causes piston member 512 to compress a fluid, such as air, gas, or liquid, within pressure chamber 516 thereby creating an opposing biasing force. This compression of fluid within pressure chamber 516 provides force absorption along axis PC at an increasing rate.
In some embodiments, as illustrated in Figures 38-46, cord set load protector 110 can comprise a spring lever assembly 600. In some embodiments, spring lever assembly 600 can comprise a spring lever 602 and a cord clamp 130 fixedly coupled to spring lever 602 and power cord 112. As illustrated in Figures 38-46, spring lever 602 can be fixedly coupled to housing 118 via one or more retaining members 604 extending from housing 118. More particularly, spring lever 602 can comprise a plurality of corresponding mounting apertures 606 (see Figure 45) sized to receive retaining members 606 therethrough. In some embodiments, retaining members 604 can be deformable, such as through heat staking or welding, to permanently retain spring lever 602 in a predetermined operable position (see Figure 44). Retaining members 604 can be spaced apart to define a plane extending between the centers thereof, wherein the plane is generally orthogonal to a longitudinal axis of power cord 112. Additionally, retaining member 604 can be a sleeve or slot formed in housing 118 for receiving and retaining an end of spring lever 602.
In some embodiments, cord set load protector 110 can comprise a cord clamp 608 fixedly coupled to spring lever 602. In some embodiments, as illustrated in Figures 38-46, cord clamp 608 can comprise a pair of clamping members 610 adapted to be coupled together via fasteners 612 (Figure 44). Specifically, each clamping member 610 can comprise an enlarged aperture 614 for permitting a shank portion of fastener 612 to pass through and a threaded aperture 616 for threadedly engaging fastener 612. Each clamping member 610 can comprise a slot 618 formed therein to capture a side of spring lever 602 and a generally circular portion 620 to capture power cord 112. In this manner, cord clamp 608 can be mounted on an end of spring lever 602 such that the slot 618 of each clamping member 610 engages a side of spring lever 602. Similarly, power cord 112 can extend between clamping member 610. Upon tightening of fasteners 612, clamping members 610 are drawn together to exert a clamping and retaining force on both spring lever 602 and power cord 112. In this manner, cord clamp 608 is fixedly coupled to power cord 112 for movement therewith. It should be appreciated that clamping members 610 are configured such that a single manufacturing piece can be used on opposing sides of spring lever 602.
With reference to Figure 45, spring lever 602 can comprise a slotted end 622 for receiving power cord 112 therethrough.
During use, if sufficient force is applied to power cord 112, the associated force is transmitted through cord clamp 608 and against spring lever 602 to deflect spring lever 602 between a relaxed position (Figures 38, 40, 42, and 44) and a deflected position (Figures 39, 41, and 43). This deflection provides force absorption along axis PC. The biasing force of spring lever 602 can be determined based upon, in part, the size and length of spring lever 602 and the material thereof. It should be understood, however, that in some embodiments additional biasing force may be desired. In such cases, a supplemental spring member 630 (Figures 40 and 41) may be used disposed between cord clamp 608 and housing 118. Supplemental spring 630 can be a compression spring having either linear or progressive spring rates. Additionally, supplemental spring member 630 could include a coil spring, torsion spring, elastomeric member, or the like. Spring member 630 can be disposed coaxial with power cord 112 to maintain alignment of spring member 630 with power cord 112. It should be appreciated that spring member 630 can be used separate from spring lever 602, such as illustrated in FIGS. 47 and 48.
In some embodiments, as illustrated in Figures 42 and 43, spring lever 602 can be pivotally coupled about an axis 650 for pivotal movement between a relaxed position (Figure 42) and a deflected position (Figure 43). In this embodiment, a torsion spring 652 can be used for applying an opposing biasing force to power cord 112 when under load.
In some embodiments, a bellmouth 634 can be used to limit the deflection of power cord 112 exiting housing 118. Bellmouth 634 can comprise a generally linear body portion 636 and a curved exit 638 having an curved profile. Bellmouth 634 can be fixedly coupled to cord clamp 608 for movement therewith such that it moves together with cord clamp 608 when power cord 112 is under load.
Referring now to Figures 49-52, in some embodiments, a biasing system 710 can comprise a plunger member 712 slidably disposed in housing 118. In some embodiments, plunger member 712 can be slidably disposed a plunger chamber 713 disposed in or formed as part of housing 11.8. It should be appreciated that plunger chamber 120 can be formed integral with housing 118 and thus is merely a portion of housing 118 or can be formed separate from housing 118 to form a subassembly positionable within housing 118.
Plunger member 712 is fixedly coupled to power cord 112 for movement therewith using a coupling member 714. Coupling member 714 can be formed in any form that permits joining of plunger ember 712 to power cord 112 for movement therewith. In some embodiments, coupling member 714 can comprise a clamping bracket having opposing sides threadedly joined together via fasteners to apply a clamping force to power cord 112. A compressible volume 716 is thus defined by plunger chamber 713, plunger member 712, and any other portion of housing 118, as desired.
In some embodiments, as illustrated in Figures 49 and 50, compressible volume 716 can comprise a biasing media 718 disposed therein. Biasing media 718 can include a plurality of elastomeric members shaped as balls, beads, pebbles, or various random shapes. This biasing media can be freely placed in compressible volume 716 to be piled, stacked, or otherwise grouped in response to movement of plunger member 712. That is, biasing media 718 can be free to flow or otherwise move within compressible volume 716 initially and yet will be otherwise restrained in a deflected position.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating plunger member 712 relative to plunger chamber 713 to the left in the figures. This translation causes plunger member 712 to compress biasing media 718 against a wall of plunger chamber 713. The opposing biasing force of biasing media 718 being compressed against the walls of plunger chamber 713 thereby creates an opposing biasing force against movement of power cord 112 along axis PC. The spring rate of this opposing biasing force can be tailored to a predetermined biasing profile through the selection of the biasing media, including the selection of materials used, media sizes, media quantity, and the like. It should be appreciated that a mixture of differing media can be used.
In some embodiments, as illustrated in Figures 51 and 52, a spring coil member 720 can be coupled between housing 118 and plunger member 712 to provide an opposing biasing force to plunger member 712. In some embodiments, spring coil member 720 comprises a spring coil having a first end 722 fixedly coupled to housing 118 and an opposing second end 724 fixedly coupled to plunger ember 712. Spring coil member 720 can extend through a portion of plunger member 712 and coupling member 714 so as to be coupled to a face 726 of plunger member 712. However, it should be appreciated that spring coil member 720 can be fixedly coupled to a back side 728 of plunger ember 712 or coupling member 714.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating plunger member 712 relative to plunger chamber 713 to the left in the figures. This translation causes plunger member 712 to draw second end 724 of spring coil member 720, thereby straightening spring coil member 720 creating an opposing biasing force against movement of power cord 112 along axis PC. The spring rate of this opposing biasing force can be tailored to a predetermined biasing profile through the selection of the material and spring characteristics of spring coil member 720.
In some embodiments, as illustrated in Figures 53 and 54, a spring cam lever 726 can be coupled to housing 118. Spring cam lever 726 can be a generally planar lever having an upturned end 728. A retaining end 730 of spring cam lever 726 can be fixedly coupled to housing 118 via a retaining feature 732 extending from housing 118. Retaining feature 732 can include a molded-in feature, such as a sleeve, for retaining retaining end 730 therein through an interference fit or other connection. Plunger member 712 can comprise a raised cam feature 734 extending from a side thereof and be slidably disposed in a guide slot 736. Raised cam feature 734 can be configured to engage and progressively deflect spring cam lever 726 in response to movement of power cord 112 and plunger member 712.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating plunger member 712 relative to guide slot 736 to the left in the figures. This translation causes raised cam feature 734 to translate along spring cam lever 726 from upturned end 728 toward retaining end 730. As a result of the proximate location of raised cam feature 734 to spring cam lever 726, spring cam lever 726 is caused to progressively deflect from an initial position to a deflected position, thereby creating an opposing biasing force against movement of power cord 112 along axis PC. The spring rate of this opposing biasing force can be tailored to a predetermined biasing profile through the selection of the material and spring characteristics of spring cam lever 726.
In some embodiments, as illustrated in Figures 55 and 56, cord set load protector 110 can comprise a breakaway connection 800. Breakaway connection 800 can comprise a first cord half 802 and a second cord half 804 being electrically connectable via a male end connector(s) 806 extending from first cord half 802 and/or second cord half 804 and a female end connector(s) 808 disposed in first cord half 802 and/or second cord half 804. Male end connector(s) 806 and female end connector(s) 808 can be configured to define both an electrical connection and mechanical connection, wherein the mechanical connection is disconnectable in response to a predetermined load applied along power cord 112. Once this predetermined load is reached, the mechanical connection is broken, thereby disrupting the electrical connection. This predetermined load (i.e. a retaining-force) can be chosen to be less than a known load that is likely to cause damage to power cord 112. A tether member 810 can be used to join first cord half 802 and second cord half 804 such that once the predetermined load is reached and the mechanical connection is disconnected, tether member 810 can retain first cord half 802 and second cord half 804 in close proximity for reconnection. Tether member 810 can be a strap member coupled to first cord half 802 and second cord half 804 via fasteners. Tether member 810 can be configured to provide a load carrying ability greater than the mechanical connection between first cord half 802 and second cord half 804.
Referring now to Figures 57-61, in some embodiments, cord set load protector 110 can comprise a biased cam assembly 900. Specifically, in some embodiments, biased cam assembly 900 can be disposed within housing 118 or, in some embodiments, can be formed outside of housing 118. With particular reference to Figure 16, biased cam assembly 900 can comprise a cam follower bracket 910, a cord clamp bracket 912, and a biasing member 914. Cam follower bracket, in some embodiments, comprises a body portion 916 having one or more cam slots 918 each sized to receive a cam follower 920 (i.e. fastener) extending therethrough. Cam followers 920 and cam slots 918 are sized to closely conform to each other to provide a non-binding, camming movement. Cam followers 920 are configured to be threadedly received within a mounting structure 922 extending from housing 118 or other equivalent support structure.
In some embodiments, cord clamp bracket 912 can comprise a bracket body shaped to include a first power cord retaining slot 924 sized to complement a corresponding second power cord retaining slot 926 formed on cam follower bracket 910 and clampingly engage and retain power cord 112 therebetween (Figures 58-61). In this way, cam follower bracket 910 can move in concert with power cord 112.
In some embodiments, cord clamp bracket 912 can comprise a pair of enlarged apertures 928 for permitting a shank portion of fasteners 930 to pass through into a corresponding threaded aperture 932 formed in cam follower bracket 910. Upon tightening of fasteners 930, cord clamp bracket 912 is drawn toward cam follower bracket 910 to exert a clamping and retaining force on power cord 112. In this manner, cord clamp bracket 912 is fixedly coupled to power cord 112 for movement therewith.
With continued reference to Figures 57-59, biasing member 914 can be disposed in a position between cam follower bracket 910 and housing 118 such that movement of cam follower bracket 910 to the left in the figures exerts a compression force on biasing member 914. Specifically, in some embodiments, biasing member 914 can be positioned such that an end of biasing member 914 engages a side wall of housing 118 or, more particularly, a sidewall of mounting structure 922. An opposing end of biasing member 914 can be positioned to engage a spring wall 934.
It should be appreciated that variations of biased cam assembly 900 can exist, such as for example biasing member 914 can be positioned such that an end engages a side wall of housing 118 and an opposing end thereof engages at least a portion of cord clamp bracket 912. In this manner, biasing member 914 can be disposed in coaxial relation to power cord 112.
During use, if sufficient force is applied to power cord 112, power cord 112 is translated thereby similarly translating cam follower bracket 910 to the left in the figures. Cam followers 920 slide within cam slots 918 to provide smooth, non-binding deflection. This translation causes biasing member 914 to compress thereby creating an opposing biasing force. This compression of biasing member 914 provides force absorption along axis PC.
It should be appreciated from the foregoing that one or more of the disclosed embodiments can be used concurrently to provide improved tailoring of the biasing profile and increased cord protection.

Claims

A power tool (10), comprising:
a tool body having a housing (118):
a motor disposed in said housing;

a power cord (112) connected to said motor; and

a cord protector (114) operably engaging said power cord, characterized in that said cord protector comprises a spring lever member (602; 726) coupled to said housing on a first end and engaging said power cord on a second end, said spring lever exerting a biasing force upon said power cord in response to a load being applied to said power cord, said spring lever recovering to an initial position in response to removal of said load.
The power tool according to Claim 1, further comprising:
a cord clamp (608: 714) fixedly coupling said second end of said spring lever to said power cord.
The power tool according to Claim 2 wherein said cord clamp comprises:
a pair of clamping members 610 each having a first slot for engaging said spring lever and a second slot for engaging said power cord.
The power tool according to any one of Claims 1 to 3, further comprising:
a spring member (630) disposed between said spring lever and said housing, said spring member exerting a biasing force upon at least one of said power cord and said spring lever.
The power tool according to Claim 4 where said spring member (630) is coaxial with said power cord.
The power tool according to any one of Claims 1 to 5 wherein said spring lever (602) is coupled to said housing at said first end through heat staking.
The power tool according to Claim 1 wherein said spring lever is pivotally coupled to said housing at said first end and said power tool further comprises a torsion spring (652) biasing said spring lever in to said initial position.