Patent Application
20140157542
1. Field of the Invention
The present invention relates to upright vacuum cleaners having a base to which a handle is pivotally mounted. In particular respects, the disclosure relates to a base construction that permits free rotational movement of the airflow-carrying portion of the base.
2. Description of the Related Art
Vacuum cleaners have been provided in a variety of configurations. One common type is the upright vacuum cleaner, which has a base that moves on the floor, and a handle pivotally mounted to the base. The base includes a suction inlet that faces the floor. A vacuum fan and motor assembly (“suction motor”) is located in either the base or the handle, and fluidly connected to the inlet to generate a suction flow of air to draw in dirt and debris. A dirt collection device, such as a filter bag or inertial (e.g., cyclonic) separator, is provided in the base or, much more frequently, in the handle. In use, the handle is leaned back and manipulated to direct the base over the floor in a series of back-and-forth motions. The upright vacuum cleaner is stored by pivoting the handle to an upright position, where it remains by gravity (if leaned forward somewhat to put the center of gravity in front of the pivot axis) or with the help of an upright handle lock mechanism. The vacuum cleaner is also sometimes placed in the upright position during use, such as when the suction motor is connected to an auxiliary cleaning hose.
It is desirable to make sure the handle lock mechanism does not permit unwanted tipping, as such can be inconvenient and may cause damage. In more recent years, it has become increasingly common to position both the suction motor and the dirt collection device in the handle. This places more weight on the handle, and makes it even more important to securely hold the handle in the upright position. Typical handle lock mechanisms use a compact pedal-operated latch on the base, which engages a corresponding hole or shelf on the handle. Examples of such devices are shown in U.S. Pat. Nos. 4,423,534 and 6,006,401, which are incorporated herein by reference. Other handle locks use spring-loaded pins or shafts to retain the handle using an articulated spring-and-catch system that permits rotation after a sufficient force has been applied to press the spring-loaded catch out of engagement. Examples of these devices are shown in U.S. Pat. No. 5,353,471 and U.S. Publication No. 2009/0276975, which are incorporated herein by reference. In devices having a relatively heavy handle, the lock may be fairly robust to bear the weight of the handle, and multi-part spring-and-catch systems can be complicated and expensive to produce.
The base of a typical upright vacuum cleaner comprises a relatively robust structure that holds supporting wheels and the main suction inlet, and carries the entire weight of the handle. Height adjustment mechanisms have been provided to adjust the height of the suction inlet relative to the floor to thereby enhance performance on various different surfaces, ranging from hardwood floors to thick carpets. Height-adjustment devices typically comprise a small wheel assembly, located just behind the suction inlet, that is moved up and down relative to the rest of the base to raise and lower the suction inlet. The wheel assembly typically bears a large portion of the base's weight, and is the first structural part of the device to strike obstacles on the floor, and therefore must be fairly strong and durable.
While various features of upright vacuum cleaners like the ones described above have been used in the art, there still exists a need to provide alternatives to such devices.
In one exemplary embodiment, there is provided a vacuum cleaner having a handle, a dirt separator mounted on the handle, a suction motor mounted in the handle, and a nozzle pivotally mounted on the handle. The handle has a first handle side and a second handle side opposite the first handle side. The dirt separator has a separator inlet for receiving dirt-laden air and a separator outlet for discharging cleaned air. The suction motor mounted has a suction motor inlet configured to generate a suction airflow into the suction motor inlet. The nozzle has a bottom face, a first side region that extends along the first handle side, and a second side region that extends along the second handle side to thus locate at least a portion of the handle between the first side region and the second side region. A suction inlet passes through the bottom face of the nozzle. The suction inlet includes an opening that is elongated along a suction inlet axis extending from the first side region to the second side region. A pivot joins the nozzle to the handle at a pivot axis that extends from the first side region of the nozzle to the second side region of the nozzle and in parallel with the suction inlet axis. The pivot includes a first pivot connection joining the first side region to the first handle side, and a second pivot connection joining the second side region to the second handle side. A base air passage extends from the suction inlet to the first pivot connection. A first handle air passage is located in the handle and extends from the first pivot connection to the separator inlet. The first handle air passage is fluidly connected to the base air passage through the first pivot connection. A second handle air passage is located in the handle and extends from the separator outlet to the suction motor inlet.
In another exemplary embodiment, there is provided a vacuum cleaner having a handle, a dirt separator mounted to the handle, a suction motor mounted in the handle, and a nozzle pivotally mounted on the handle. The handle has an upper end, a lower end, a first handle side, and a second handle side opposite the first handle side. The dirt separator has a separator inlet for receiving dirt-laden air and a separator outlet for discharging cleaned air. A handle air passage is formed in the handle, and has a handle air passage inlet located at the first handle side at the lower end of the handle, and a handle air passage outlet connected to the separator inlet. The suction motor has a suction motor inlet connected to the separator outlet. The nozzle includes a nozzle shell having a bottom face with an elongate suction inlet passing through the bottom face of the nozzle shell, a first side arm that extends backwards from the suction inlet and pivotally connects the nozzle shell to the first handle side at the lower end of the handle, and a second side arm that extends backwards from the suction inlet and pivotally connects the nozzle shell to the second handle side at the lower end of the handle. A nozzle air passage is formed in the first side arm. The nozzle air passage extends backwards from the suction inlet to the first handle side at the lower end of the handle, and has a nozzle air passage inlet connected to the elongate suction inlet, and a nozzle air passage outlet connected to the handle air passage inlet, so that the suction motor draws dirt-laden air into the suction inlet, through the nozzle air passage and the handle air passage and into the dirt separator.
The recitation of this summary of the invention is not intended to limit the claims of this or any related or unrelated application. Other aspects, embodiments, modifications to and features of the claimed invention will be apparent to persons of ordinary skill in view of the disclosures herein.
A better understanding of the exemplary embodiments may be understood by reference to the attached drawings, in which like reference numbers designate like parts. The drawings are exemplary and not intended to limit the claims in any way.
The exemplary embodiments described herein relate to upright vacuum cleaners and more specifically to various features of the bases of such vacuum cleaners.
An exemplary embodiment of an upright vacuum cleaner 100 is shown in
For convenience, the positional relationships of the various parts of the vacuum cleaner 100 are described herein with reference to their orientation when the base 102 is placed on a horizontal surface being cleaned. The fore-aft direction, indicated by arrow 108, lies in the horizontal plane and is the primary movement direction during cleaning. The terms “front,” “rear,” and the like relate to respective positions in the fore-aft direction 108. The lateral direction, as indicated by arrow 110, is perpendicular to the fore-aft direction 108, but within the horizontal plane. The terms “left,” “right,” “side,” and the like refer to positions in the lateral direction 110. The vertical direction, as indicated by arrow 112, is orthogonal to the horizontal plane and, thus, to both the fore-aft direction 108 and lateral direction 110. The terms “up,” “down,” “above,” “below,” and the like refer to positions in the vertical direction 112. It will be appreciated that these terms are used for convenience, and not to delineate strict and exclusive positional relationships. For example, an object that is said to be “above” another part need not be directly above that part in the vertical direction 112, but instead can also be offset in one or both of the other directions. Similarly, a part that extends “vertically” or in the “forward” direction may also extend in another direction.
The base 102 includes an inlet nozzle 114 located in front of the pivot axis 106. The inlet nozzle 114 includes a downward-facing inlet 206 (
The suction motor 328, which may alternatively be located in the base 102 or other parts of the handle 104, is connected to the inlet nozzle 114 by a system of one or more air passages. The air passage system also connects to one or more dirt collection devices 126, such as a cyclone separator, filter bag, pleated or panel filter, or the like. The dirt collection devices 126 may be upstream or downstream of the suction motor 328, or both. The dirt collection device may integrated in the vacuum cleaner 100 (as in the case of a non-removable chamber for a filter bag) or connectable to the rest of the vacuum cleaner 100 (as in the case of typical removable cyclone separator units). The details of such dirt collection devices 126 are well-known in the art and not the immediate subject of this application, and thus are not described in detail herein.
The inlet nozzle assembly 201 comprises a lower nozzle shell 202 and an upper nozzle shell 204 that are joined together to form the inlet nozzle 114. The lower nozzle shell 202 includes the inlet 206 through which air enters the vacuum cleaner. A brushroll 208 is mounted to rotate within the inlet nozzle assembly 201, with the bristles of the brushroll 208 extending through the inlet 206 to contact and agitate the surface being cleaned. The brushroll 208 may be powered by a dedicated motor (not shown), as known in the art, but in a more preferred embodiment, the brushroll 208 is powered by a shaft 210 extending from the suction motor 328, by way of an intermediate belt 212 or gears.
The upper and lower nozzle shells 204, 202 join together to form a left arm 214 in the left side region 116 and a right arm 216 in the right side region 118. The left and right arms 214, 216 extend backwards from the inlet nozzle 114 to connect to the handle 104. The end of each arm 214, 216 includes a nozzle mounting boss 218. The nozzle mounting bosses 218 connect with other parts to form a pivoting connection between the nozzle assembly 201 and the handle 104, such as described below. The nozzle mounting bosses 218 may be formed as part of either or both of the upper and lower nozzle shells 204, 202, or a separate part that is connected to the nozzle assembly 201. The left and right arms 214, 216 may provide a belt tunnel 222 on one side to enclose the drive belt 212, and a base air passage 224 on the other side to fluidly connect the inlet nozzle 114 to a corresponding air passage 324 (see, e.g.,
The exemplary carriage 200 preferably is the primary structure for supporting the weight of the vacuum cleaner 100 on the surface being cleaned. The carriage 200 comprises a frame 226 to which one or more floor-contacting supports are connected. For example, the frame 226 has two rear support wheels 124 located behind the pivot axis 106, and two front support wheels 228 located in front of the pivot axis 106. The wheels 124, 228 may be mounted by respective axles, and may include bushings, bearings or other rotating supports, as desired. It will be appreciated that either of the foregoing pairs of wheels may be replaced by a single wheel, one or more skids, or groups of more than two wheels.
The handle 104 is pivotally mounted to the carriage 200 so that the handle 104 can be moved between an upright storage position and an inclined operating position. The inclined operating position may be a single, discrete orientation relative to the carriage 200, but, more preferably, encompasses a continuous range of orientations to accommodate the natural inclination to continuously raise and lower the handle 104 as the vacuum cleaner is moved back and forth over the floor.
In the shown embodiment, the handle 104 is pivotally mounted to the carriage by a left mounting ring 230 and a right mounting ring 232 that are disposed on opposite sides of the frame 226. The left and right mounting rings 230, 232 have an opening 233 between them to receive the bottom of the handle 104, and are joined by one or more rigid cross-members 236.
Each mounting ring 230 includes a generally circular opening 308 into which the shaft 300 fits. The opening 308 has inward flanges 310 that are sized to pass through the gaps 306 as the shaft 300 is moved into the opening 308. Once the shaft 300 is fully installed, the nozzle mounting boss 218 is rotated relative to the carriage 200 (e.g., by rotating the entire lower nozzle shell 202) to position the inward flanges between the first and second flanges 302, 304. In this position, the mounting rings 230, 232 are captured in place on the nozzle mounting boss 218 with respect to axial movement along the shaft 300, but free to rotate around the nozzle mounting boss 218 about a rotation axis that is parallel with, and may be collinear with, the handle rotation axis 106.
The mounting rings 230, 232 each include a circular carriage mounting boss 312, which may form the outer perimeter of the opening 308, such as shown, or be spaced from the opening 308. The carriage mounting boss 312 engages a circular handle mounting boss 314 that extends laterally from the side of the handle 104. The carriage mounting boss 312 and handle mounting boss 314 together form a bearing surface to transfer the weight of the handle 104 to the carriage 200. To do so, the carriage mounting boss 312 may either surround (as shown) or be surrounded by the handle mounting boss 314. Low friction coatings, bearings or a bushing material may be used to reduce wear and resistance between these parts, but the use of simply conventional plastic materials is expected to provide a suitable rotating connection. The carriage mounting boss 312 and handle mounting boss 314 define the handle rotation axis 216. In a preferred embodiment, the handle rotation axis is collinear with a rotation axis of the belt drive shaft 210. If desired, one or more travel stops 322 may be provided on the carriage 200 or handle 104 to prevent relative rotation between the carriage 200 and handle 104 beyond a predetermined point. The shown travel stop 322 (which may be provided on both sides of the handle 104) fits into a groove on the inner wall of the mounting ring 230, 232 and the groove is sized to permit a limited range of relative rotation. The outer surface of the mounting ring 230, 232 may be shaped to match the contour of the adjacent portions of the handle 104 to provide a smooth aesthetic appearance.
The nozzle assembly 201, carriage 200 and handle 104 of
It will be appreciated that alternative embodiments may use other arrangements to mount the nozzle assembly 201 and carriage 200 to the handle 104. For example, the parts may be assembled using conventional mounting pins or bearing shafts. As another example, the arrangement of the parts may be reversed, with the mounting rings 230, 232 located outward of the nozzle assembly mounting bosses 218. Other variations and modifications will be apparent to persons of ordinary skill in the art in view of the present disclosure.
On the left side of the exemplary embodiment, the belt drive shaft 210 extends into the belt tunnel 222. The belt tunnel 222 may be openable to service the belt 212. For example, the lower and upper nozzle shells 202, 204 may be connected by readily-accessed service screws 278 that can be removed to access the belt 212, or a separate removable panel may be provided on or between the shells 202, 204. The nozzle mounting boss shaft 300 may include an inner boss 316 that closely surrounds a tunnel 318 through which the belt drive shaft 210 passes, to help prevent the egress of motor debris (e.g., carbon dust).
On the right side, the base air passage 224 turns inwards and fluidly connects to a first handle passage 324 located inside the handle 104. The nozzle mounting boss shaft 300 on this side may have a relatively close tolerance to the inside of the handle mounting boss 314 to help prevent air leaks at this joint. Such tolerance may be provided simply by sizing the entire shaft to fit closely within the handle mounting boss 314, or by adding an outward flange 322 that extends towards the handle mounting boss 314, such as shown in
It is often desirable to store an upright vacuum cleaner handle in the upright position, such as when the cleaner is not in use or when it is being used with an accessory cleaning hose. To this end, the vacuum cleaner 100 may include a storage lock that prevents the handle 104 from pivoting backwards relative to the base 102 when it is unattended. Conventional storage locks typically comprise a foot-operated hook on the base, and a corresponding slot on the handle into which the hook fits to prevent handle rotation. Such devices require a separate foot-pedal to actuate the hook and a spring to bias the hook into the engaged position. This assembly can add unwanted cost to the device, must be robustly made to withstand the full weight of the operator (and thus heavy), and is subject to breakage. It also can be difficult to assemble the parts, as the spring often must be compressed during assembly. Furthermore, the area of the base 102 to which the foot-pedal is connected also may need to be reinforced to hold the pedal and resist the spring force, and support the user's weight when the pedal is activated. Another problem with conventional foot-pedals is that they are often mistaken for a power button (and vice-versa), particularly by operators who are unfamiliar with the device or unable to see the markings on the pedals, which leads to annoyance and dissatisfaction with the product. Other storage locks comprises a spring-loaded catch that may be released by overcoming the spring force. Such devices use a movable sliding or pivoting catch, along with a separate spring that biases the catch into place. The small surface area of the catch can require relatively strong local reinforcements to the vacuum cleaner structure to resist point loads, and the separate spring adds cost and complexity. Spring-loaded storage locks also may not be suitable for relatively heavy cleaners, because the weight of the cleaner may accidentally act to release the lock. While the storage locks described above may be used in some embodiments, a more preferred embodiment does away with a separate storage lock assembly and instead uses an integral storage lock system.
An example of an integral storage lock system is illustrated in the exploded view of
The protrusion 400 comprises an extension of the handle 104, and may be a separate attached part or molded integrally with the handle's housing. In the shown embodiment, the protrusion 400 is a wedge-shaped radial extension of the housing, but other shapes may be used. The protrusion 400 rotates with the handle 104, and moves through an arc of travel 402. The arc of travel 402 is centered on the handle pivot axis 106, and extends between an upright end 404 (where the protrusion 400 is located when the handle 104 is in the upright position with respect to the base 102), and a reclined end 406 (where the protrusion 400 is located when the handle 104 is at its lowest inclination with respect to the base 102). The arc of travel 402 may comprise any suitable range of movement, such as a range of approximately 20 to 120 degrees, as measured around the handle pivot axis 106. The crossbeam 238 is positioned to intersect the arc of travel 402 near the upright end 404, to thereby contact and hold the protrusion 400 with the handle 104 in the upright position, such as shown in
The handle 104 is reclined from the storage position by applying an unlocking force to move the protrusion 400 past the crossbeam 238. During this movement, the protrusion 400 presses against and temporarily deforms the crossbeam 238, such as shown in
Once the protrusion 400 clears the crossbeam 238, such as shown in
The handle 104 is returned to the upright position by moving the handle 104 forward until a second side 412 of the protrusion 400 contacts a second side 414 of the crossbeam 238, and then applying a locking force to cause the protrusion 400 to deform the crossbeam 238. The locking force is generated by applying opposite rotation forces to the handle 104 and the base 102, but in this case it may only be necessary to push forward on the handle 104 with a hand, as the necessary force on the base 102 can be applied by contact with the floor. If the required locking force is great enough, it may be necessary to tip the vacuum cleaner 100 forward onto the front of the base 102, and perhaps even to push down on the handle 104 with the vacuum cleaner leaned forward, to generate the necessary force.
The unlocking and locking forces can be selected and adjusted by modifying the shapes and elastic moduli of the protrusion 400 and crossbeam 238. For example, forming the one or both of the contacting sides of the protrusion 400 and crossbeam 238 as a gradual slope can reduce the apparent required locking or unlocking force, but may allow some relative movement even when the parts are locked together. Forming one of both of the contacting sides as a steep ramp would increase the apparent locking or unlocking force, but potentially provide a more distinct lock with less slack. In the shown exemplary embodiment, the first side of the protrusion 400 and the first side 410 of the crossbeam 238 abut one another on a plane that has a relatively large angle relative to the arc of travel 402, as shown in
The length and cross-sectional shape of the crossbeam 238 also affect its rigidity and thus the amount of force necessary to unlock and lock the handle 104. In the shown embodiment, the crossbeam 238 extends laterally across the of the opening 233, and may provide structural support to hold the rear wheels 124 in proper alignment. To provide the necessary stiffness as a structural element, while still being resilient enough to act as a deformable lock, the crossbeam 238 may be formed as a flexible spar 242 and a relatively rigid spar 244 that are assembled together or integrally formed as a single structure that spans the opening 233. In this case, the crossbeam 238 is a molded plastic part (which preferably is integrally molded with the frame 226, but may be a separate part), and the flexible spar 242 and rigid spar 244 are formed by dividing the crossbeam 238 with a laterally-elongated slot 246. The slot 246 may be an open slot that passes all the way through the crossbeam 238 (as shown), a closed slot that does not pass all the way through the crossbeam 238, or a combination of slot structures. Multiple slots 246 also may be provided to further modify the stiffness of the crossbeam 238. In the shown embodiment, the single open slot 246 reduces the stiffness of the crossbeam 238, so that the flexible spar 242 flexes into the space within the slot 246 to permit the protrusion 400 to move between the storage and upright positions, and the rigid spar 244 does not flex any appreciable amount during locking and unlocking. An example of this arrangement is illustrated in
The location and size of the protrusion 400 also can affect the locking and unlocking forces. In the shown embodiment, the protrusion 400 is located midway between the ends of the crossbeam 238, and halfway across the opening 233, on the centerline of the handle 104. This places the protrusion 400 at the most flexible part of the crossbeam 238. In other embodiments, other locations may be used. The protrusion 400 may be relatively large, to distribute the loading force to reduce point loads that could cause fatigue or excessive wear. For example, the protrusion may be at least about 1 inch wide or wider, to distribute the load to a correspondingly-sized portion of the crossbeam 238. In addition, the protrusion 400 itself may be made with some resilience such that it also deforms to permit locking and unlocking.
While these arrangements are preferred, it will be appreciated that variations may be made while providing essentially the same function and results. For example, the crossbeam 238 and protrusion 400 may be interposed in other embodiments, with the protrusion being on the base 102, and the crossbeam 238 being on the handle 104. As another example, the crossbeam 238 may be a cantilevered beam that extends part-way across the opening 233.
The exemplary embodiment and variations thereof are expected to provide benefits over conventional handle lock arrangements. The crossbeam 238 and protrusion 400 are readily formed as parts of conventional plastic molds, and require no moving parts or added springs, and therefore may not add any substantial costs (or any costs at all) to the product. The use of a flexible crossbeam 238 also eliminates the need to have a release pedal and its associated hardware and mounting supports, which may significantly reduce weight. In addition, the locking and unlocking forces may be borne by the relatively large areas of the crossbeam 238 and protrusion 400, as opposed to the small hooks and slots used in conventional devices, which distributes the locking and unlocking forces across a large area and allows the parts to be made from relatively light and thin-walled materials that do not need to resist the point loads generated by conventional locks. The use of a crossbeam 238 that completely spans the distance between the handle pivot locations also allows a relatively large deflection distance without generating local stresses that could fatigue or wear away the parts. Also, the use of a slot 246 to form a flexible spar 242 and a rigid spar 244 and allows the crossbeam 238 to act both as a rigid structural frame element and as a deformable lock mechanism, which opens up the possibility of locating the locking mechanism behind the pivot axis 106 without having to add any significant extra bulk to the device. Other features and benefits will be apparent from the present disclosure and practice of the invention.
Referring back to
The knob 248 may be accessed directly, or through a corresponding access hole 258 through a corresponding boss 250′ formed on the upper nozzle shell 204. When the inlet nozzle assembly 201 is assembled, the bosses 250, 250′ form a single structure that extends backwards from the inlet nozzle 114, and the top of the knob 248 is accessed from above the inlet nozzle assembly 201, as shown in
It will be appreciated that changes may be made to the foregoing height adjustment mechanism, and variations and modifications will be apparent to persons of ordinary skill in the art in view of the present disclosure. It will also be appreciated that other kinds of height adjusting mechanism may be used on other embodiments. For example, the knob and its circular cam may be replaced by a sliding linear cam, such as shown in U.S. Patent Publication No. 2006/0070209, or a rotating wheel, such as shown in U.S. Pat. No. 7,895,707.
Embodiments also may include features to disengage the brushroll 208 when the handle 104 is moved to the upright position. This may be desirable to prevent the brushroll 208 from continuing to rotate in one place on a carpet or other floor surface when the handle 104 is upright, but the vacuum cleaner 100 remains on (e.g., during above-floor cleaning with an accessory hose). Where the brushroll 208 has a dedicated drive motor, a microswitch or other device may be provided to turn off the dedicated motor upon placing the handle 104 into the upright position. Such microswitches and brushroll shut-off circuits are known in the art and need not be described here. In embodiments in which the brushroll 208 is driven by the suction motor 328, such as in the shown example, power from the suction motor 328 to the brushroll 208 can be terminated by disengaging the drive belt 212 by any of a variety of mechanisms. Known devices include, for example, belt tensioner pulleys that are slacked to release belt tension, idler pulleys onto which the belt 212 is slid, and belt lifters that lift the belt 212 out of engagement with the drive shaft 210. Such devices are conventional and need not be described here. Alternatively, the brushroll 208 can continue to be powered, but simply lifted out of contact with the underlying floor by a nozzle-lifting mechanism.
The illustrated exemplary embodiment includes a nozzle-lifting mechanism in the form of a liftoff lever 260. The liftoff lever 260 is mounted on the carriage 200 by two pivot bosses 262 on the liftoff lever 260 that fit into corresponding pivot grooves 264 on the carriage 200. When so mounted, the liftoff lever 260 is free to rock between a first position in which a front end 266 of the liftoff lever 260 is lowered and a back end 268 of the liftoff lever 260 is raised, and a second position in which the front end 266 of the liftoff lever 260 is raised and the back end 268 of the liftoff lever 260 is lowered.
The front end 266 is located under the inlet nozzle assembly 201. For example, the shown liftoff lever's front end 266 may be shaped to fit immediately behind the height adjustment knob's bearing surface 252. When the liftoff lever 260 is in the first position, the front end 266 is lowered and clear of the inlet nozzle assembly 201, which permits the inlet nozzle assembly 201 to lower and raise freely as the operator adjusts the height adjustment knob 248. When the liftoff lever 260 is placed in the second position, the front end 266 presses upwards on the bottom of the inlet nozzle assembly 201 and lifts it high enough for the brushroll 208 to clear the underlying floor. In this latter position, the inlet nozzle assembly 201 may be above the highest setting provided by the height adjustment knob 248. In other embodiments, the liftoff lever 260 may be used even if a height adjustment mechanism is not provided.
The liftoff lever 260 may be operated by a separate control such as a foot pedal, but more preferably is operated by the handle 104 as the handle 104 is moved into the upright position. For example, the handle 104 may include one or more protrusions 270 that rotate with the handle 104. As the handle 104 is rotated to the upright position, the protrusions 270 eventually contact the back end 268 of the liftoff lever 260 to move the liftoff lever 260 into the second position to raise the inlet nozzle assembly 201. Other engaging mechanisms, such as slots in the handle 104 and corresponding ribs or lobes extending from the liftoff lever 260, may be used in other embodiments.
The operation of the exemplary liftoff lever 260 is illustrated in the cross-section views of
The foregoing exemplary embodiment and variations thereof are expected to provide a simple, inexpensive, and lightweight liftoff mechanism having a single moving part interposed between the handle 104 and the base 102. However, other activation mechanisms may be used in other embodiments. For example, the liftoff mechanism may be connected to and driven by a linkage that is drivingly connected to the handle 104, or it may be a manually-operated mechanism that is operated by a foot pedal or a similar manual control.
Various other features may be provided in the base 102. For example, a spring 272 may be provided to pull the inlet nozzle assembly 201 towards the carriage 200, to prevent the inlet nozzle assembly 201 from freely lifting above the height established by the height adjustment knob 248. The inlet nozzle assembly 201 also may include a belt cover (not shown) that encloses the belt 212 and closes off the left arm 214 to inhibit dirt and air entering the inlet 206 from fouling the belt 212. Also, a flexible wiper 274, bristles, or other cleaning members may be connected to the base 102 to contact the floor to assist with cleaning. Other variations and modifications will be apparent to persons of ordinary skill in the art in view of the present disclosure.
As shown in
The separated inlet nozzle assembly 201 and carriage 200 arrangement also may allow a simpler inlet nozzle assembly construction that does away with complex molded parts having numerous cavities as found in conventional devices. As shown in
The remaining space between the inlet nozzle 114 and the handle 104 may be open, which can provide additional benefits. For example, providing an opening or openings through the inlet nozzle assembly 201 may permit the operator to view the carriage 200 to confirm its position relative to the inlet nozzle assembly 201 or view the floor below the carriage 200. In this case, there are two openings 500 (
The carriage 200 may have one or more openings 276 located below the open portions 500 of the inlet nozzle assembly 201. Further openings also may be provided by gaps 600 (
It has been discovered that embodiments such as those described herein can provide significantly enhanced operating characteristics on certain carpet surfaces, as compared to conventional upright vacuum cleaners. In particular, it has been found that vacuum cleaners constructed in a manner similar to that shown in
The operating force F1 is a measure of the effort it takes to move the vacuum cleaner. It may be measured according to ASTM International standard No. F1409-00 (Reapproved 2010), which measures the relative work necessary to move the operating vacuum cleaner forwards and backwards across a given surface. The data developed by this standard is reported in foot-pounds. In preliminary testing, it was found that embodiments similar to those described herein with respect to
The magnitude of the operating force F1 has often been considered to be a function of various factors. One factor is the suction force pulling the base and carpet into close contact (“suction lock”), which causes friction and resists movement. Wheel rolling resistance and friction between the carpet and the lower base surface are also factors. Suction lock is exacerbated in dense carpets that inhibit airflow through the carpet fibers when the suction inlet is pressed against the carpet surface. One typical solution to excessive operating force F1 is to raise the suction inlet well above the carpet using a height adjustment mechanism. However, not all vacuum cleaners have height adjusters, and even those that do may not extend far enough to place the suction inlet out of suction lock range (particularly when the front wheels sink deeply into the carpet). In all cases, when the suction inlet is raised well out of range of the carpet to mitigate suction lock, it can greatly reduce cleaning efficiency and lead to customer dissatisfaction. Another possible solution is to form the bottom of the base 702 with a large “skid” plate that rests on the carpet to help hold the suction inlet 714 at or near the top of the carpet surface, but such skid plates increase friction, can be costly (if made of metal), and simply may not work as desired. Still another solution is to provide excessively large side vents into the suction inlet to draw air from the sides to prevent suction lock. This solution also has the problem of reducing the concentration of airflow at the target surface and reducing cleaning performance. Furthermore, such vents will affect operation even when suction lock is not being experienced, such as during use on hard floors or low carpets, and it is usually desirable to not to make such vents excessively large.
It has been found that another factor influencing the generation of suction lock and high operating force in upright vacuum cleaners is the arrangement and construction of the base. As shown in
Despite providing the overall stability desirable for upright vacuum cleaners, the arrangement as shown in
The horizontal vector component FH is the force that moves the vacuum cleaner 700 forward against resistance. A first resistance force FX1 is generated by contact between the front wheel 710 and the underlying surface 716, and second resistance force FX2 is generated by contact between the rear wheel 708 and the underlying surface 716. The resistance forces FX1, FX2 may include rolling resistance and basic friction components, both of which are proportional to weight. Thus, because the rear wheel 708 bears most of the vacuum cleaner's weight, the second resistance force FX2 should be significantly higher than the first resistance force FX1. Additional resistance forces opposing horizontal vector component FH may be created by suction lock, as described above, and by frictional contact between the base 702 and the surface 716. If a rotating brush is used, it may generate a further resistance force if it rotates backwards relative to the base 702, but more often the brush rotates in a manner to pull the base 702 forward to thereby negate some or, in extreme cases (e.g., very low carpet with high friction between the carpet and the rotating brush), all of the resistance.
As the typical vacuum cleaner 700 is moved on a carpeted surface, the front and rear wheels 710, 708 experience an increased rolling resistance, resulting in a higher operating force F1. When suction lock is added, the total operating force F1 can become extremely high. Under these circumstances, it would be desirable to allow the suction inlet 714 to freely float on the carpet surface to reduce the effect of suction lock. Contact between the bottom surface of the base 702 and the carpet (particularly if there is a large skid plate) could generate a force to push the suction inlet 714 upwards to provide the desired float, but it has been found that this force appears insufficient to reduce suction lock and alleviate the generation of a high operating force F1, particularly in dense carpets. Instead, it is believed that a large rotational moment M generated between the rear wheel 708 and the handle pivot 706 (which are spaced apart by a fixed distance d to provide stability) forces the base 702, including the front wheel 710 and suction inlet 714 into the carpet, further increasing the resistance forces opposing the horizontal vector component FH. (A similar moment may be generated between the front wheel 710 and the handle pivot 706.) The problem can be magnified by several factors. For example, carpet may catch on the back edge of the suction inlet 714. As another example, the front wheels 710 may be relatively small to fit under the base 702, and therefore subject to significantly higher rolling resistance than a larger wheel would be when encountering the carpet piles. Still further, the force necessary to float the suction inlet 714 must be large enough to raise most of the base 702, the front wheels 710, the wheel carriage 712, and even the handle (i.e., everything in front of the rear wheel pivot). Even a very large skid plate may not be able to generate sufficient force to overcome the rotational moment M and lift all of the parts to provide enough float to mitigate the suction lock.
Stated simply, the configuration of the conventional vacuum cleaner 700 couples the operating force F1 to the base 702 in such a way that the operating force F1 pushes the suction inlet 714 into the carpet, making it impossible for the suction inlet 714 to float freely, and increasing the total resistance to movement. It is noted that some conventional vacuum cleaners may be constructed such that they do not experience the foregoing phenomenon. For example, the device shown in U.S. Pat. No. 3,031,710 (which is incorporated herein by reference) avoids the generation of a moment M to press the base downward by making the inlet nozzle and rear wheel pivot about the handle's pivot axis. However, this device lacks any kind of manual height adjustment, and the rear wheel is not spaced from the handle pivot and therefore does not provide the degree of support that is desirable in, and expected of, modern vacuum cleaners.
It has been found that the foregoing problems can be mitigated, without sacrificing stability, by providing a suction inlet that can move up and down (“float”), even when the vacuum cleaner is being pushed forward by an operating force F1.
As explained above, the exemplary vacuum cleaner 100 comprises an inlet nozzle assembly 201, a carriage 200, and a handle 104. The handle 104 is pivotally mounted on the carriage 200, and the carriage 200 has rear wheels 708 and front wheels 710 that support the weight of the handle 104. The inlet nozzle assembly 201, which carries the suction inlet 206, is pivotally mounted to the handle 104, and moves generally independently from the carriage 200. The carriage 200 and inlet nozzle assembly 201 may be functionally connected by a height-adjusting knob 248, which sets a minimum height of the inlet nozzle assembly 201 relative to the carriage 200. An optional spring 272 may be provided to pull the inlet nozzle assembly 201 towards the carriage 200. The inlet nozzle assembly 201 is free to rise relative to the carriage 200 upon the application of an upward force, provided the force is sufficient to stretch the spring 272 if one is provided.
Meanwhile, the inlet nozzle assembly 201 can pivot about the handle pivot axis 106 separately from the carriage 200. During the operation described above, the inlet nozzle assembly 201 is not directly driven into the carpet 800 by the moment M generated by the carriage 200, and the influence of the moment M on the inlet nozzle assembly 201 is limited to whatever force can be generated by the spring 272 (if one is provided). Under these circumstances, it is believed that contact between the lower surfaces of the inlet nozzle assembly 201 and the carpet 800 can generate a lifting force FL that is sufficient to elevate the inlet nozzle assembly 201 from a starting position (shown by dashed line 802) to a point where suction lock, friction between the inlet nozzle assembly 201 and the carpet 800, and other forces, are significantly reduced as compared to conventional devices, resulting in a greatly reduced operating force F1 requirement. It will be understood that when the inlet nozzle assembly 201 is lifted as shown in
The degree of float may be regulated by, for example, altering the spring constant of the spring 272 (if provided) and changing the weight of the inlet nozzle assembly 201. Reducing the spring constant or making the inlet nozzle lighter are expected to reduce the operating force F1, but may result in reduced cleaning performance if taken to an extreme. The shape of the lower surface of the inlet nozzle assembly 201 also can affect the float properties. For example, a gently sloping surface 416 may be provided in advance of the suction inlet (see
As will be apparent from the foregoing, constructing the inlet nozzle assembly 201 to rotate about the pivot axis 106 independently from the carriage 200 effectively decouples the dynamics of the inlet nozzle assembly 201 from the dynamics of the carriage 200. The spring 272 (when present) provides an operational dynamic link between the carriage 200 and the inlet nozzle assembly 201, but still permits independent rotation upon the application of sufficient force to deform the spring 272. (As used herein, “independent” and permutations thereof includes relative movement upon the application of a force to deform the spring 272.) The spring 272 may have constant or graduated spring rate. The spring 272 also may include slack to allow unrestricted relative movement before it is necessary to begin deforming the spring for further independent movement, or be preloaded to require a minimum predetermined force threshold before independent movement begins.
The exemplary spring 272 is a coil spring, operated in tension, and has a spring constant of approximately 6.7 pounds/inch. The spring 272 is mounted such that it expands in a direction parallel with the coil, so that its effective spring constant in operation is about the same as the rated spring constant. The spring 272 is mounted approximately 5.5 inches from the handle pivot axis 106, and the front of the inlet nozzle assembly 201 is about 8.5 inches from the handle pivot axis 106. This differential distance provides a leverage ratio of about 1.5:1 for a force FL applied at the front of the inlet nozzle assembly 201. For a spring 272 with an effective spring constant of 6.7 pounds/inch this results in a lifting force FL requirement of about 4.5 pounds per inch of travel (as used herein, the measure of the lifting force requirement excludes spring preload that may need to be overcome to begin movement, and the degree of such preload may depend on the position of a height adjustment mechanism). In other embodiments, the leverage ratio and spring constants may vary. It is expected that a lifting force FL requirement of 2.5 to 6.5, and more preferably 3.5 to 5.5, will provide favorable operation in various circumstances, and for relatively lightweight inlet nozzle assemblies. Heavier inlet nozzle assemblies may benefit from a lower lifting force FL requirement to allow the desired float, and lighter inlet nozzle assemblies may benefit from a heavier lifting force FL requirement to prevent significant degradation to the cleaning performance that might occur if the inlet is allowed to rise too far. It will be understood that the description herein and recitation in the claims of precise numerical values is done for expedience, and that operating embodiments may have some variation in the actual measured value due to measuring variations, manufacturing variances and minor inconsequential deviations introduced during the design process. Unless otherwise indicated, all values described and recited herein should be treated as target approximations (e.g., 4.5 pounds per inch will be understood by the person of ordinary skill in the art to be about 4.5 pounds per inch).
In the shown example, the inlet nozzle assembly 201 and the carriage 200 are collectively interconnected to the handle 104 by an arrangement of pivoting members (see
It will be appreciated that it is not strictly necessary in all embodiments to mount the inlet nozzle assembly 201 to rotate about the handle pivot axis 106. For example, similar benefits may be obtained by mounting the carriage 200 on the handle 104 to rotate about the handle pivot axis 106, and mounting the inlet nozzle assembly 201 on the handle 104 to rotate about a second axis that is offset from the handle pivot axis 106. The second axis would be fixed with respect to the handle 104, which allows the use of a simple rigid air passage from the inlet nozzle assembly 201 to the handle 104 (such as shown in
Furthermore, it is speculated that the inlet nozzle assembly 201 can be pivotally mounted to the carriage 200 at some location other than the handle pivot axis 106. However, this arrangement may more directly couple the motion of the inlet nozzle assembly 201 to the moment M created by the operating force F1. This coupling affect may be reduced by mounting the inlet nozzle assembly 201 to pivot at a location closer to the rear wheels 124, which may increase the leverage applied by the lifting force FL. Using a relatively low pivot location also may help mitigate the coupling affect, particularly if the pivot location is below the point of contact between the carpet 800 and the bottom of the inlet nozzle assembly 201 to thereby covert friction into a lifting moment. Mounting the inlet nozzle assembly 201 to pivot about a point on the carriage 200 other than the handle pivot axis 106 also would cause the inlet nozzle assembly 201 to pivot about an axis that is not fixed relative to the handle 104—that is, as the carriage 200 rotates relative to the handle 104, so too would the axis about which the inlet nozzle assembly 201 rotates. This would complicate efforts to provide a rigid air passage directly from the inlet nozzle assembly 201 to the handle 104 (a flexible hose could readily be used, however), but this arrangement could simplify the dynamics between the inlet nozzle assembly 201 and the carriage 200 as compared to embodiments described above that mount the inlet nozzle assembly 201 to rotate about a fixed axis on the handle 104 that is separate from the handle pivot axis.
It will be understood that the foregoing explanation is provided as a theoretical explanation for the improved performance of embodiments of the invention as compared to conventional devices. There may be other explanations for the discovered phenomena, and the invention is not intended to be bound by any theory of operation. It will also be understood that the foregoing embodiments may be modified in various other ways. For example, the carriage 200 may have any number of front and rear wheels 228, 124 (e.g., a single centrally-located front wheel instead of two spaced wheels), and these may be replaced or supplemented with other kinds of support, such as skids and the like. Also, the inlet nozzle assembly 201 may include its own wheels or other supports. Other variations and modifications will be apparent to persons of ordinary skill in the art in view of the present disclosure.
The present disclosure describes a number of new, useful and nonobvious features and/or combinations of features that may be used alone or together. The embodiments described herein are all exemplary, and are not intended to limit the scope of the inventions. It will be appreciated that the inventions described herein can be modified and adapted in various and equivalent ways, and all such modifications and adaptations are intended to be included in the scope of this disclosure and the appended claims.
This is U.S. application is a continuation of U.S. application Ser. No. 13/789,895 filed Mar. 8, 2013 which is a continuation-in-part of U.S. application Ser. No. 13/712,512 filed Dec. 12, 2012.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13789895 | Mar 2013 | US |
| Child | 14014973 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13712512 | Dec 2012 | US |
| Child | 13789895 | US |
