Patent Publication Number: US-6219883-B1

Title: Locking assembly for push broom

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to an assembly for attaching handles to an implement head such as a broom head. More particularly, the invention relates to an assembly for threadably attaching a handle to an implement head and locking the handle so that it cannot be detached from the head during usage. 
     A standard implement for which the invention has applicability comprises a separable, elongated handle and one of a variety of implement heads, including brooms, mops, squeegees, etc. For a push broom, the head is made up of bristles and a rigid bristle supporting base, with the base often made of wood, plastic, light metal or other rigid material. The head typically has two predefined, centrally located holes or mounting bores through its upper surface in angularly offset relationship for receiving one end of the handle. One hole is located on a front side of the head and the second hole is located on an opposite side of the head. This allows the handle to be switched from one hole to the other such as, for example, when the bristles become worn in one pushing direction. The holes are typically threaded to allow engagement with the end of the handle which has complementary threads. 
     While the threaded attachment of the handle to the head provides a functional implement, several inherent problems are present with this arrangement. During use, the threaded attachment between the handle and head routinely loosens due to a force producing a torque imbalance wherein the head is urged to pivot about the handle. If not constantly tightened, the head may become completely separated from the handle. Over tightening of the handle can lead to stripped threads on the handle or within the mounting bore. The distribution and transport of assembled push brooms, with their heads jutting from their handles, is cumbersome and awkward. Shipment of assembled brooms also requires additional valuable cargo or container space compared to shipment of unassembled brooms. Displaying assembled push brooms for retail merchandising and sale presents similar handling and space requirement problems. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a simple, convenient and reliable method for securing a handle to an implement head. 
     It is another object of the invention to provide a handle-securing assembly which may be used with any standard two-holed head without modification. 
     It is a further object of the invention to provide an apparatus which locks the handle and head together when assembled and also prevents misplacement of the handle and head when unassembled. 
     These and other objects are accomplished by the present invention which comprises an elongated handle and a locking plug for an implement head. The elongated handle has a first end including a threaded portion which is engageable with a threaded mounting bore located in the head. The handle first end includes at least one transverse aperture. The locking plug includes a head connected to a threaded shank and terminates in a locking pin projecting from the shank. The locking pin is preferably coaxial with a locking plug longitudinal axis and sized to fit within the handle transverse aperture. 
     The implement head includes two angularly offset mounting bores. The mounting bores are internally threaded and have intersecting axes. In use, the handle first end is threadably engaged within one of the mounting bores. The locking plug shank is threadably engaged within the other of the mounting bores and the locking pin is approximately axially aligned with the handle transverse aperture. Further threaded engagement of the locking pin shank within the mounting bore drives the pin into the handle transverse aperture, locking the handle from rotational and axial movement and thereby securing the handle to the head. Preferably, the locking plug shank defines a face which is engageable against the outside surface of the handle first end when the pin is driven into the extended portion aperture to further secure the handle. The handle first end portion may also include radially arrayed faces to better cooperate with the shank face. The locking plug preferably includes provisions for either manual actuation or for mechanical actuation in cooperation with a tool. 
     In a different embodiment, the handle first end is coaxially mounted to a ferrule. The ferrule includes a threaded portion coaxial with, and projecting from, the handle first end; and the previously described transverse aperture. In use the handle and ferrule assembly is threadably engaged with one head mounting bore and the locking plug threadably engaged with the other head mounting bore, as previously described, so that the locking pin is driven within the ferrule transverse aperture. The locking plug face may also engage the outside surface of the ferrule threaded portion. 
     In another embodiment, the locking plug pin is moveable within the locking plug between an extended position projecting from the shank face and a retracted position. The pin is biased toward the projected position and includes an attachment for moving the pin to the retracted position. With the handle or ferrule assembly threadably engaged into one mounting bore, the locking plug can be threadably engaged with the other mounting bore to drive the locking pin, in the extended position, into the transverse aperture, thereby securing the handle to the head. If disassembly of the handle from the head is desired, the pin may be moved to the retracted position, so that the pin is withdrawn from the transverse aperture, and rotation of the handle is allowed. Thus, the handle can be removed from, and reattached to, the head without removal of the locking plug. In a variation of this embodiment, the displaceable pin is permanently mounted to the implement head, without the use of the threaded plug. Movement of the pin against its bias to the retracted position still allows the handle to be rotated for assembly or disassembly. With the pin biased into the transverse aperture, the handle is secured to the head. 
     In any variation in which the aperture is a transverse bore, the engagement of the locking pin and bore immobilizes the handle from both rotational and axial movement. This allows the use of a non-threaded handle or ferrule which mounts to the head by a slip or interference fit within a non-threaded mounting bore. 
     In a further embodiment, the handle or ferrule threaded end is bisected by a transverse slot. Threaded engagement of the handle or ferrule threaded end within one mounting bore locates the slot at the intersection of the mounting bore axes. Threaded engagement of the locking plug shank with the other head mounting bore drives the locking pin into engagement with the transverse slot, thereby rotationally immobilizing the handle and securing the handle to the head. Alignment of the locking pin with the transverse slot is less critical than alignment of the locking pin and a transverse aperture. 
     A flexible leash or retainer may connect the locking plug to the handle or ferrule. In this manner, the locking plug and handle cannot be separated and lost. Further, if the locking plug is threadably engaged within the head, the handle will be connected to the head by the leash, preventing misplacement but allowing more compact storage of the head adjacent the longitudinal axis of the handle. 
     In any embodiment, the assembled handle is secured to the head so that no rotational (and in some embodiments axial movement) of the handle with relation to the head is possible. While the invention allows the handle to be securely fastened to a head, it should be noted that the handle is quickly and easily removable after removal of the locking plug, or in some embodiments movement of the locking plug pin to the retracted position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will be evident to one of ordinary skill in the art from the following detailed description, made with reference to the accompanying drawings, in which: 
     FIG. 1 is a side view, partly in schematic and partly in phantom, of a locking assembly of the invention installed to a broom head, with portions of the broom head removed to illustrate the invention; 
     FIG. 2 is a side view, partly in schematic and partly in phantom, of a locking assembly of the invention installed to a broom head, with portions of the broom head removed to illustrate a second embodiment of the invention; 
     FIG. 3 is a side view, partly in schematic and partly in phantom, of a locking assembly of the invention installed to a broom head, with portions of the broom head removed to illustrate a third embodiment of the invention; 
     FIG. 4 a  is a side view of a locking plug of a locking assembly illustrating a plug head with wings for manual actuation; 
     FIG. 4 b  is an end view, partly in phantom, of the locking plug of FIG. 4 a;    
     FIG. 5 a  is a side view of a locking plug of a locking assembly illustrating a plug head adapted for mechanical actuation in cooperation with a tool; 
     FIG. 5 b  is an end view, partly in phantom, of the locking plug of FIG. 5 a;    
     FIG. 6 a  is a side view, partly in phantom, of a locking plug of a locking assembly illustrating a displaceable locking pin biased into an extended position; 
     FIG. 6 b  is an end view, partly in phantom, of the locking plug of FIG. 6 a;    
     FIG. 7 is a side view, partly in schematic and partly in phantom, of a locking assembly of the invention installed to a broom head, with portions of the broom head removed to illustrate a fourth embodiment of the invention; 
     FIG. 8 is a side view, partly in schematic and partly in phantom, of a locking assembly of the invention installed to a broom head, with portions of the broom head removed to illustrate a fifth embodiment of the invention; and 
     FIG. 9 is a side view, partly in schematic and partly in phantom, of a locking assembly of the invention installed to a broom head, with portions of the broom head removed to illustrate a sixth embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An inventive implement in accordance with the present invention, indicated generally in FIG. 1 as  10 , comprises an elongated handle  12  mounted via a ferrule  30  to a head  14  and secured by a locking plug  16 . The implement head  14  includes an upper surface with two angularly offset mounting faces  18 ,  20 . The mounting faces  18 ,  20  each include a predefined, centrally located, typically internally threaded, mounting bore  22 ,  24  respectively. The mounting bores  22 ,  24  extend into, or through, the thickness of the head  14 . The mounting bores  22 ,  24  each have an axis angularly offset from each other, typically at or around 90°, with the axes intersecting. 
     A handle  12  includes a control end (not shown) for manually handling and controlling the implement head  14  and an opposing attachment end  26 . The attachment end  26  typically terminates in a ferrule  30  which projects along the longitudinal axis of the handle  12 . The ferrule  30  includes a threaded portion  34 . The threaded portion  34  is adapted for threadable engagement within each of the head mounting bores  22 ,  24 . The ferrule  30  includes at least one transverse aperture  36  adjacent the free end  32 . The transverse aperture in this embodiment is preferably a cylindrical bore through opposing sides of the ferrule  30 . Naturally, multiple, radially spaced apertures may be used. The aperture also need not completely diametrally traverse the ferrule  30 . The aperture  36  is perpendicular to the handle longitudinal axis. The ferrule  30  should be made of metal or other material strong enough to withstand twisting and pushing forces. Alternatively, the ferrule may be constructed of plastic overlying a metal core. 
     The junction of the ferrule threaded portion  34  and mounted end creates a shoulder  38 . The shoulder  38  acts as a rotational stop against the mounting face  18 , thereby limiting threaded engagement of the ferrule  30  within the head mounting bore  22 . The shoulder  38  also acts to transmit force between the handle  12  and the head  14 . When the ferrule threaded portion  34  is sufficiently threadably engaged with the mounting bore  22 , the transverse aperture  36  will be positioned at the intersection of the mounting bore axes. 
     Annular spacers (not shown) fitting over the ferrule threaded portion  34  and disposed between the mounting face  18  and ferrule shoulder  38  may be used to vary the axial position of the transverse aperture  36  within the mounting bore  22 , while maintaining engagement of the ferrule shoulder  38  and mounting face  18 . Thus, the spacers, would allow a single handle  12  and ferrule  30  to be used with a variety of different heads, having different mounting bore depths while still positioning the transverse aperture  36  at the intersection of the mounting bore axes. 
     As shown in FIG. 2, the ferrule free end  32  may also include a concentric unthreaded extension  40 , with the ferrule transverse aperture  36  located in this extension  40 . The extension  40  may be round or include at least one substantially flat face angularly positioned around the handle longitudinal axis. It should be understood that the handle, if constructed of a sufficiently strong material, may include the same features as a ferrule for use with a locking plug and head in the same manner as the ferrule. 
     The locking plug  16  includes a head  44  connected to a threaded shank  46 . The shank free end terminates at a face  48  from which a locking pin  50  projects coaxially with a longitudinal axis of the locking plug  16 . The threaded shank  46  of the locking plug  16  is adapted to threadably engage one of the head mounting bores  22 ,  24 . As the locking plug shank  46  is threadably engaged within a mounting bore  24 , the locking pin  50  will be driven into the mounting bore  24 . Continued threaded engagement of the locking plug shank  46  within the mounting bore  24  will drive the locking pin  50  into a suitably positioned ferrule transverse aperture  36 , thereby locking the ferrule  30  and attached handle  12  from rotational or axial movement. If the locking pin  50  is not perpendicular to the handle longitudinal axis when the locking plug shank  46  is threadably engaged within the mounting bore  24 , the aperture  36  will need to be large enough to accommodate the angular offset of the pin  50  and aperture  36 . Further threaded engagement of the locking plug  16  within its respective mounting bore  24  will engage the plug face  48  against the ferrule  30 , additionally securing the ferrule  30  and handle  12  from rotational or axial movement. 
     While the head  44  and shank  46  of the locking plug  16  may be constructed of any suitable material, the locking pin  50  should preferably be of steel or other material strong enough to withstand the twisting forces applied to the pin  50  during use of the implement  10 . The locking pin  50  should also be of sufficient length so that it will fully engage the ferrule transverse aperture  36 . 
     The locking plug  16  may be adapted to ease manual actuation of the locking plug shank  46  into the mounting bore. This may be done by, for example, wings  52  projecting from the locking plug head  44  perpendicularly to the longitudinal axis of the locking plug  16 . The wings  52  facilitate application of torque applied to the locking plug  16  with a user&#39;s fingers. See FIGS. 4 a  and  4   b . Alternatively, as shown in FIGS. 5 a  and  5   b , the locking plug head  44  may be adapted for cooperation with a tool to permit mechanical actuation of the locking plug shank  46  into threaded engagement with the mounting bore. This adaptation may take any of a number of well known forms, such as, for example, slots, cross slots, or sockets within the locking plug head for cooperation with driver tools; or opposing flats on the locking head diameter for cooperation with wrenches. 
     In another embodiment, shown in FIG. 3, the ferrule aperture is in the form of at least one transverse slot  58  slot originating at the ferrule free end  60  and progressing inwardly along the longitudinal axis. When the ferrule  56  is threadably attached to one mounting bore  22 , the locking plug  16  can be engaged into the other mounting bore  24 , with the locking pin  50  projecting into or through the slot  58 . In this condition, the handle  12  is prevented from rotational movement, thereby locking the handle  12  to the head  14 . For certain applications, the use of the slot  58  is advantageous over a transverse aperture  36  since the axial position of the slotted ferrule  56  within the mounting bore  22  is not critical and the locking pin  50  may engage the slot  58  at any of a plurality of axial positions. The locking pin  50  will not prevent axial movement of the slotted ferrule  56  and mounted handle  12  within the head  14  however. 
     In an alternative embodiment, shown best in FIG. 6 a , the locking plug  64  defines an axial bore  66 . The locking plug pin  68  is moveable within the bore  66  between an extended position projecting from the shank face  72  and a retracted position. The locking plug pin  68  is biased toward the extended position, such as by, for example, a spring  70 . A handle  74  attached to the locking pin  68  extends beyond the locking plug head  76  to allow actuation of the locking pin  68  against the bias to the retracted position. As previously described, the locking plug  64  is engaged within a mounting bore. The displaceable locking pin  68  in the extended position cooperates with the ferrule transverse aperture  36  or slot  58  as previously described to secure the attached implement handle  12  from movement out of head  14 . Actuation of the locking pin handle  74  moves the locking pin  68  to the retracted position, simultaneously withdrawing the locking pin  68  from the ferrule transverse aperture  36  or slot  58 . With the locking pin  68  in the retracted position, the handle  12  may be freely rotated to assemble or disassemble the implement  10  without removal of the locking plug  64  from the head  14 . 
     In different variation shown in FIG. 7, the locking pin  82  is mounted within the head  84  and biased toward an extended position with a pin locking end  86  projecting into an intersecting mounting bore  88 . The opposing locking pin handle  90  projects from the implement head  84 , allowing the pin  82  to be moved against the bias and out of the intersecting mounting bore  88 . With the pin  82  retracted, the handle  92  may be moved into or out of the mounting bore. With the pin locking end  86  biased into the transverse aperture  95  of the handle  92 , the handle is captured and prevented from moving either radially or axially. While the handle  92  is shown with a tapered end  94 , which is a slip or interference fit in an unthreaded tapered mounting bore  88 , this variation is also capable of securing a previously described threaded handle with either a transverse aperture or slot in a threaded mounting bore. 
     In a further embodiment shown in FIG. 9, a handle  12  is mounted to a threaded ferrule  108 . The ferrule  108  includes a coaxially projecting shaped extension  110 . The locking plug  112  includes a shank  114  with ridges  116  which is directly insertable in a head mounting bore. The ridges  116  prevent the locking plug  112  from backing out of the mounting bore. A yoke  118  is mounted to the shank  114 . In use, the ferrule  108  is threaded into one mounting bore. The locking plug  112  is inserted in the other mounting bore, so that the yoke  118  engages the ferrule shaped extension  110 . With the yoke  118  and extension  110  engaged, rotation of the ferrule end  108  out of the mounting bore is prevented. 
     The disclosed embodiments are each capable of variation within the embodiment. In one variation the locking plug pin  98  and ferrule transverse aperture  100  are threaded at the same pitch as the mounting bores  22 ,  24 . Threaded engagement of the locking plug shank  46  and the mounting bore  24  also serves to thread the locking pin  98  into the aperture  100 , thereby securing the handle  12  to the implement head  14 . See FIG.  8 . In other variations, the outside surface of a handle or ferrule includes serrations or planar areas (not shown) for cooperation with the locking plug face to secure the handle to the head. 
     A retainer or a leash  104  may be attached to the locking plug  16  and either the handle  12  or ferrule  30 ,  56 . At least one of the retainer  104  attachments must allow free rotation of the attached component so that the handle  12  may be rotationally assembled and dis-assembled from the head  14  without interference by the retainer  104 . Preferably, the retainer  104  is permanently attached to the locking plug head  44  as by, for example, an aperture  106  in the locking plug head  44  and a loop of the retainer  104  permanently fastened therethrough. See, for example, FIGS. 1,  2  and  3 . 
     It can readily be seen that the inventive locking assembly includes numerous advantages. Construction of the assembly is simple, inexpensive and requires no moving or pivoting parts. The locking assembly may be set or released manually. The locking mechanism is positive and requires no adjustments once set. No brackets must be attached to the implement head and any standard two hole head can be used. The locking assembly renders a normal head connection sturdy enough so that in some cases a heavy duty head with support arms or brackets is not necessary. 
     While preferred embodiments of the foregoing invention have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and scope of the present invention.