Blade change carrier device

[0001] Not applicable.

[0002] Not applicable.

[0003] Not applicable.

[0004] (1) Field of the Invention

[0005] The present invention generally relates to the field of rotary driven blades, and devices making it easier and faster to change blades. More particularly, this invention relates to a carrier fastened to the motor-driven rotary drive shaft of a machine, such as a lawn mower; the carrier holds the blade in a manner that is secure in the locked configuration, but which can readily unlocked for removal of the blade and replaced with another blade.

[0006] (2) Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98.

[0007] Although carriers for blades are generally known in the field, such carriers are usually for reciprocating saws and other similar devices, and such carriers typically address only the blade-changing aspect without addressing the need to do with a device having both strength and durability while also being easily operated by somebody without requiring specialized tools, training, strength or an inordinate amount of time.

[0008] U.S. Pat. No. 3,877,146 issued to Pittinger discloses a blade holder having a blade with a central circular hole, a hub or cylindrical body, a blade locating means, and elastically deformable projections or fingers securely holding the blade; the blade may be released by pivoting it about the blade locating means on the holder. The holder is connected with the drive shaft, and holds the blade for rotation. The retaining fingers are formed integrally with the holder. As the blade is rotated from the assembly position, the opposite half-sections of the blade slide under the retaining fingers until they abut near the main body of the holder. As the blade is turned to the locking position, a slight torque must be applied to force it under the raised area by slightly deforming the retaining fingers. Each raised area acts as a detent mechanism.

[0009] U.S. Pat. No. 2,875,569 issued to Sauer discloses a blade mounting device for a lawn mower having a drive shaft that rotates a flexible blade, the device having the blade flexibly attached by a spring to a face plate having a blade supporting structure that is secured to the drive shaft. The blade includes a protrusion that is engageable with the wall portion of the face plate. When the blade is assembled to the face plate, the headed screw extends through the cap, the coil spring, the blade and the face plate, and is threaded coaxially into the end of the shaft with the coil spring between the blade and the head of the screw. The spring normally holds the blade against the face plate to keep the protrusions in the recesses or holes in the face plate and against the wall portion of the face plate.

[0010] U.S. Pat. No. 4,586,257 issued to Rittenhouse discloses a blade holder including a holder body connected to a rotary drive shaft. The holder body has a wide and flat outer (lower) face upon which the specialized blade is secured between tabs. The blade essentially slides into two guide grooves along the side edges of the flat outer face, held in place by lip tabs. A central engaging means engages a circular central hole in the blade. The engaging means includes an engaging pin, and a compression spring which biases the engaging pin outward (downward) from the flat outer face and through the blade hole. The blade can be easily removed from the holder by pressing the engaging pin (which is exposed on the bottom of the device) inward against the compression spring and sliding the blade until tabs are between lip tabs, so that the blade can be lifted away from the holder.

[0011] None of the aforementioned references discloses: (a) a housing having a bottom and a false floor and a sidewall slot-opening forming a channel therebetween holding the blade; and (b) a housed disk having a tip downstanding from its floor, and (c) a housed compression spring biasing the blade-engaging tip through an opening in the housing's false floor and through a center hole in the blade to lock it within the channel.

[0012] Although the present invention has several embodiments, the version generally described is essentially a device facilitating removal and mounting of a blade having an axial mounting hole for attachment to a rotary drive shaft. The device generally comprises (includes) a housing having a bottom, a false floor defining an axial opening having the configuration of the blade's mounting hole. The housing also may have a sidewall slot-opening defining a channel accepting the blade between the housing bottom and false floor; the axial opening defines a passageway into the channel. The device also generally includes a housed blade-lock member having an axial tip snugly acceptable to the axial opening. When the blade-lock member is in a raised position, the tip extends downwardly only to the axial opening, without protruding into the channel enough to inhibit insertion of a blade, and without protruding into the blade's axial mounting hole to inhibit removal of the blade from the channel. When the blade-lock member is in a lowered position, the tip extends downwardly substantially into the channel and through the blade's axial hole, to prevent it from being removed. The housing's housing sidewall may further include a lever port for accepting a lever (such as a screw driver) for raising the blade-lock member to the raised position. The device also generally includes a locking means for biasing the blade-lock member's axial tip downward, and locking the blade into the device. The device has a cap having a fastening means linking the device to the rotary drive shaft, so that rotation of the drive shaft likewise rotates the housing and blade locked therein.

[0013] One primary object of the present invention is to provide a blade-change carrier device that makes it easier and faster to change blades.

[0014] Another primary object of the present invention is to provide a carrier device that is sturdy enough to withstand the rigors of the rotary blade environment, while facilitating the removal and re-installation of blades in the field without requiring specialized tools, training, strength or an inordinate amount of time.

[0015] Other objects will be apparent from a reading of the written description disclosed herein, together with the claims.

[0034] These drawings illustrate certain details of certain embodiments. However, the invention disclosed herein is not limited to only the embodiments so illustrated. The invention disclosed herein may have equally effective or legally equivalent embodiments.

[0035] For the sake of simplicity and to give the claims of this patent application the broadest interpretation and construction possible, the following definitions will apply:

[0036] The term “accept” or derivative thereof essentially means sized to allow an identified item to fit within with only slight leeway, so as to support or guide without binding.

[0037] The term “housed” or derivative thereof essentially means enclose, wholly or partially sufficient to perform the function required by the context of usage.

[0038] Directional terms such as “upward” or “downward” (or derivatives thereof) are intended merely as guides within the context of a device used in connection with an essentially vertical rotary drive shaft having its free end extending downward; in the context of an essentially horizontal drive shaft, those terms will change to the extent needed to reflect the change in orientation of the device.

[0039] Also for the sake of simplicity and to give the claims of this patent application the broadest interpretation and construction possible, the conjunctive “and” may also be taken to include the disjunctive “or,” and vice versa, whenever necessary to give the claims of this patent application the broadest interpretation and construction possible. Likewise, when the plural form is used, it may be taken to include the singular form, and vice versa.

[0040] The invention disclosed herein is not limited by construction materials to the extent that such materials satisfy the structural and/or functional requirements. For example, any material may be used so long as it satisfies the function for which it is being used, such as providing the structural strength and durability to both lock the blade into the carrier sufficiently strong for operation of the blade, while allowing ready removal of the blade when desired.

[0041] Similarly, the invention is not limited to any particular embodiment described or depicted herein. For example, other versions than those specifically disclosed herein will suffice, so long as each embodies the required elements or limitations.

[0042] The invention is essentially a quick-change blade carrier for a rotary mower having a drive shaft with an internally threaded bore. The carrier includes a housing linked by its cap to the mower's drive shaft, and enclosing a blade-engagement member having a blade-engaging tip downstanding from its floor and a spring to bias the member (and tip) downward through a center hole in the blade held within a channel in the bottom of the housing. More particularly, the carrier includes:

• • [0043] 1. an essentially cylindrical housing having a bottom and a false floor and a sidewall slot-opening forming a channel therebetween holding the blade;
  • [0044] 2. an essentially circular cap snugly anchorable within the housing, and having a central aperture receiving a fastening means (drive-bolt) for screwing snugly into the bore of the drive shaft;
  • [0045] 3. a housed disk having a non-round-shaped tip downstanding from its underside; and
  • [0046] 4. a housed locking means including a compression spring, biasing the disk (and blade-engaging tip) through a non-round-shaped opening in the housing's false floor and through a non-round-shaped center hole in the blade to lock it within the channel.

[0047] These are the basic elements or limitations of the invention, although other features may be available. An example of such an additional element includes a centralized non-round-shaped indent in the bottom of the housing, for seating the star-shaped tip downstanding from the underside of the disk and extending through a star-shaped opening in the center of the blade.

[0048] Several embodiments are disclosed, primarily divided into those relating to a version having a shorter drive bolt with an essentially standard flattened head, and a version having a longer drive bolt capable of both firmly fastening the device's cap to the rotary draft shaft and having sufficient length below the cap to align a compression spring along the axis of the device. Typically the long-bolt version requires only one compression spring, although additional compression springs (that are not impaled by the drive bolt) may be added in a manner done for the short-bolt version.

[0049] Both versions include a device facilitating removal and mounting of a blade having an axial mounting hole for powering by a rotary drive shaft, the device may include (having or including) a housing having a bottom, a false floor defining an axial opening having the configuration of the blade's mounting hole, and a sidewall slot-opening defining a channel accepting the central portion of the blade between the housing bottom and false floor, the axial opening of the false floor defining a passageway into the channel. Also included is a housed blade-lock member having an axial tip snugly acceptable to the axial opening, downstanding to the axial opening when the blade-lock member is in a second raised position; it is also downstanding substantially into the channel and through the blade's axial hole when the member is in a first lowered position. The housing sidewall may further include a lever port for accepting a lever for raising the blade-lock member to the raised position. Also included is a locking means for biasing the blade-lock member's tip to the first lowered position and locking the blade into the channel. There is also a cap having a fastening means linking the device to the rotary drive shaft.

[0050] More particularly, the locking means may include at least one compression spring between the cap and the blade-lock member, biasing the blade-lock member downward to the first lowered position. The housed blade-lock member may include a disk housed within a cylindrical housing. The cap may include an axial aperture accepting a drive-bolt rotatably fastened within the rotary drive shaft's internally threaded axial bore; the circumference of the cap should be anchored firmly within the housing.

[0051] If the blade has an axial mounting hole having a non-round configuration (such as a square, hexagonal, octagonal, or lobed opening), the housing false floor should defines a non-round axial opening having the configuration of the blade's non-round mounting hole. The housed blade-lock disk should also have a non-round axial tip snugly acceptable to the axial opening and the blade's axial mounting hole, so that it can snugly impale both the false floor and blade to lock the blade into the channel of the carrier device.

[0052] Primarily in the short-bolt version of the invention, the disk has an upper surface defining a plurality of indentations, each accepting the base of a compression spring seated therein. The compression spring may be cylindrical, conical, or any other configuration sufficient to perform its function of biasing the blade-locking member (the “floating” disk) in the downward (locking) position with its downstanding tip extending through the blade's axial mounting hole. The disk's upper surface may also define an axial well sized to accept the head of the drive-bolt when the disk is in the raised position. This configuration has the advantage of allowing the housing to have a “lower profile”.

[0053] If the rotary drive shaft has a non-round cross section (besides having an internally threaded bore for accepting the device's drive bolt), the device's cap may further include an upper surface having an axial void snugly acceptable to that non-round end of the rotary drive shaft. This will assist in translating the rotation of the drive shaft to rotation of the cap (and anchored housing), which will in turn assist in rotation of the blade locked within the device's channel.

[0054] In the short-bolt version, to attach the device to the mower, the user threads the drive-bolt upward through the central aperture of the housing cap, and screws it into the internally threaded bore of the mower's rotary drive shaft; the head of the drive bolt is seated snugly against the underside of the housing cap. (Common hardware and techniques may be used wherever applicable in this device, such as such as lock-washers and/or countersinking.) The compression springs are then inserted into the indentations in the upper surface of the blade-lock disk within the housing. The user then anchors the cap within the housing, using bolts running through the housing sidewall and into the perimeter of the cap within the housing. (Common techniques and hardware may be used as applicable in the device, such as using bolts with low profile heads and/or countersinking them into the housing sidewall so that the bolts do not protrude too much.) In this resting state, the springs bias the disk downward, causing its axial tip to extend through the corresponding axial opening in the false floor of the housing, far enough to extend through the corresponding axial mounting hole of any blade situated within the channel between the false floor and bottom of the housing.

[0055] In the long-bolt version (with the longer drive bolt impaling the compression spring and aligning it with the axis of the device), the blade-lock disk may further include an axial portal; the drive bolt may therefore extend through the compression spring and into the portal. This will also allow the blade-lock disk to be leveraged upward more without being stopped by the drive bolt. Depending upon the configuration of the axial tip downstanding from the underside of the disk, the axial portal may or may not extend entirely through the disk (and axial tip). Moreover, in this version, the drive bolt also has a nut rotatably fastened upwardly until firmly against the underside of the cap, allowing it to both link the cap to the rotary drive shaft and align the compression spring with the axis of the device.

[0056] To attach the invention to the mower, the user threads the longer drive-bolt through the central aperture of the housing cap, and screws it into the internally threaded bore of the mower's rotary drive shaft; a nut is screwed up the opposite end of the drive-bolt, until the nut is seated snugly against the underside of the housing cap. (Common hardware such as lock-washers may be used wherever applicable, in this device.) The compression spring is then threaded over the drive-bolt until it abuts the nut, and the end of the drive-bolt is threaded through a center hole of the disk (to center the spring against the upper surface of the disk, surrounding any axial port therein). The non-round-shaped tip downstanding from the underside of the disk is inserted through a correspondingly non-round-shaped opening in false floor of the housing. The user then anchors the cap within the housing, using bolts running through the housing sidewall and into the perimeter of the cap within the housing. (Common techniques and hardware may be used as applicable in the device, such as using bolts with low profile heads and/or countersinking them into the housing sidewall so that the bolts do not protrude too much.) In this resting state, the spring biases the disk downward, causing its axial tip to extend through the corresponding axial opening in the false floor of the housing, far enough to extend through the corresponding axial mounting hole of any blade situated within the channel between the false floor and bottom of the housing.

[0057] A more preferred embodiment for a device facilitating mounting and removal of a blade having an axial mounting hole for powering by a rotary drive shaft, the device may include:

[0058] (a) a cylindrical housing having a bottom, a false floor defining an axial opening having the configuration of the blade's mounting hole, and a sidewall slot-opening defining a transverse channel accepting the blade between the housing bottom and false floor, the axial opening defining a passageway into the channel;

[0059] (b) a housed blade-lock disk including an underside including an axial tip snugly acceptable to the axial opening, downstanding to the axial opening when the blade-lock disk is in a raised position, and downstanding substantially into the channel and through the blade's axial hole when the disk is in a lowered position, the housing sidewall further including a lever port for accepting a lever for raising the blade-lock disk to the raised position; and

[0060] (c) a cap having a fastening means including an axial aperture accepting a drive-bolt rotatably fastened within the rotary drive shaft's internally threaded axial bore and firmly linking the cap thereto, the circumference of the cap anchored within the housing.

[0061] The housed blade-lock disk may further include an axial tip having a non-round cross section configuration snugly acceptable to a blade's non-round mounting hole, and may further include an upper surface defining a plurality of indentations, each accepting the base of a compression spring seated therein to bias the disk towards a lowered position, the upper surface also defining an axial well, and wherein the head of the drive-bolt is accepted within the axial well when the blade-lock disk is in the raised position.

[0062] Alternatively, the housed blade-lock disk may further include an axial tip having a non-round cross section configuration snugly acceptable to a blade's non-round mounting hole, and may further include an upper surface defining an axial portal, the drive bolt further extending through the compression spring and into the portal, the drive bolt having a nut rotatably fastened upwardly until firmly against the underside of the cap.

[0063] The axial tip may have a non-round cross section configuration snugly acceptable to corresponding blade hole configurations known in the mower blade industry. More particularly, the axial tip may have a non-round cross section resembling a 5-lobed star-shaped configuration snugly acceptable to a corresponding blade hole configuration known in the mower blade industry.

[0064] Besides the device disclosed herein, the invention includes a method of using the device installed on a rotary drive shaft for mounting a blade having an axial mounting hole. Such method of must may include the steps of:

[0065] (a) inserting a lever into the lever port of the device, and leveraging the blade-lock disk to a raised position;

[0066] (b) aligning the blade in the housing's channel so that the blade's axial mounting hole is aligned with the axial tip of the blade-lock disk; and

[0067] (c) releasing the leverage and removing the lever from the lever port.

[0068] The method may further include removing the blade from the device by the following steps:

[0069] (a) inserting a lever into the lever port of the device, an leveraging the blade-lock disk to a raised position;

[0070] (b) removing the blade; and

[0071] (c) releasing the leverage and removing the lever from the lever port.

[0072] To insert a blade into the channel or remove it from the channel, the user grasps a screw driver (or similar lever-like object) and inserts the tip into an elongated hole in the housing sidewall, then leverages the disk upward (against the compression spring) to thereby withdraw the star-shaped tip from the channel. Discontinuation of the leveraging causes the spring to again push the disk downward, the star-shaped tip again extending into the channel (and locking into place any blade positioned therein).

[0073] Those skilled in the art who have the benefit of this disclosure will appreciate that it may be used as the creative basis for designing devices or methods similar to those disclosed herein, or to design improvements to the invention disclosed herein; such new or improved creations should be recognized as dependent upon the invention disclosed herein, to the extent of such reliance upon this disclosure.