CN111084714A

CN111084714A - Multifunctional impact massager conforming to human engineering

Info

Publication number: CN111084714A
Application number: CN201911009687.4A
Authority: CN
Inventors: S·李; A·加尔菲奥; T·弗赖伊
Original assignee: Bode Co Ltd
Current assignee: Bode Co Ltd
Priority date: 2018-10-23
Filing date: 2019-10-23
Publication date: 2020-05-01
Anticipated expiration: 2039-10-23
Also published as: CN111084714B; CN211723937U; CN115068300A

Abstract

An impact massager is generally Y-shaped in which first and second handle portions are adapted to be held by first and second hands of a user, respectively, and an impact massage head reciprocates along an axis lying in a major arc defined by the two handle portions. One purpose of the device is to allow a user to grip the device with both hands while providing a percussive massage to the lower back muscles thereof. The device has a rotation mechanism that enables the user to rotate the reciprocating axis through an arc of approximately 120 degrees relative to the handles, and the extension handle cooperates with one of the handle portions to provide the user with great versatility.

Description

Multifunctional impact massager conforming to human engineering

Cross Reference to Related Applications

This application is a partial continuation of U.S. patent application serial No. 29/663,757 filed on 9/18/2018, the entire contents of which are incorporated herein as if fully set forth herein.

Technical Field

The invention relates to the field of electric massagers. More particularly, the present invention relates to the field of multi-functional, ergonomic impact massagers.

Background

For ease of discussion, the electric massager, hereinafter simply referred to as a "massager," provides pleasure and muscle pain relief effects after intense physical activity (e.g., competitive or strenuous activity). The benefits of chiropractic therapy to reduce Delayed Onset Muscle Soreness (DOMS) have been widely documented in the medical literature since the early 1900 s. The massagers may be of the vibration type, the impact type, and others. Many vibratory massagers and impact massagers are designed and sold in a variety of configurations.

The working principle of the impact massager is to drive the massage head to do reciprocating linear motion so that the massage head repeatedly impacts the massaged muscles or other tissues. For example, U.S. patent publication 2013/0261516 to Cilea discloses a battery operated impact massager with variable frequency and variable power, and interchangeable massage heads. The Cilea device looks much like a jigsaw, which is commonly used in construction, but with slight modifications, an impact massage head is provided at the end of the reciprocating shaft rather than the saw blade.

One design goal of the massager is to make the device ergonomically-easy to use, both for the individual user and for the therapist using the device on the subject patient, without requiring the user or therapist to twist their body or limbs to an uncomfortable position to receive the desired massage at the user's desired target location, or to hold the device in a manner that becomes uncomfortable or fatiguing for a short period of time. Another design goal, particularly for impact massagers, is that the device can be easily used to press any one of a number of potential target locations on the user's body with a wide range of pressures, from light to very high, depending on the needs of the user, again without causing excessive stress or fatigue to the person applying the device.

Disclosure of Invention

The present invention relates to an impact-type electric massager, or simply "massager", which is ergonomic and has multiple functions. The device allows for a wide variety of application pressures to be used at various target locations on the human body, such that the device can effectively reach locations on the body that are not effectively reached by existing massagers, particularly for individual users using the device on their own. The device also allows for reduced fatigue in use, compared to various existing massagers, whether individual users or therapists.

According to an illustrative embodiment, an impact powered massager has a body including first and second handle portions extending from a central portion along first and second axes, respectively. The first and second handle portions define an obtuse angle therebetween, i.e., an angle greater than 90 degrees but less than 180 degrees, and preferably about 120 degrees. The reciprocating output shaft has an impact massage head (such as a ball) attached thereto for delivering impact massage to the subject. The reciprocating output shaft nominally subtends a large arc defined by two handle portions, which form the arms of the "Y" and the output shaft forms the base of the "Y", thus defining a generally Y-shaped device. The reciprocating motion of the output shaft defines a reciprocating axis. A rotation mechanism or "hinge" in the broad sense allows rotation about an axis of rotation through a large angle, preferably about 120 degrees, relative to the two handle portions. The rotational lock allows the device to be locked at a desired angle. One or more handle portions releasably mate with the handle extension so that the extension can be easily added to or removed from the device.

By allowing angular rotation of the output shaft through a large angle of about 120 degrees, and with a removable extension handle, a user can easily and without excessive distortion apply the device to many areas on their body, including the back, providing an impact massage thereto. When the user uses the device on their lower back, the two handle portions are aligned at a natural angle so that the user holds both of their hands on their back, grasps both handle portions with their hands, and pulls the massage head against their back to provide a gentle percussive massage to their lower back muscles.

By allowing versatility of application without excessive twisting or stretching, the device defines a highly ergonomic and versatile impact massager. The device also provides a multi-functional, ergonomic device that may be used by a massage therapist to impact massage a subject.

Accordingly, in one aspect, the present invention is directed to an impact powered massager having a body with a central portion and first and second handle portions adapted to be grasped by first and second hands of an operator, respectively. The handle portion extends from the central portion such that they form a small angle of between 75 ° and 180 ° therebetween, and preferably an angle of about 120 °. The motor drive assembly is at least partially located in the body. The motor drive assembly includes an electric drive motor that generates a rotational output, and a gear transmission that converts the rotational output of the motor into a reciprocating output at an output shaft located within a large arc between the handle portions, and a massage head such as a massage ball is mounted at an end of the output shaft. Preferably, the massage heads can be easily replaced. The device may be provided with a plurality of different massaging heads. The two handle portions may be of slightly different sizes when measured at the respective circumferences of the plurality of massage heads, to allow users of different hand sizes to use primarily the handle portion that best matches their hand size.

The rotation mechanism or hinge allows the output shaft to rotate relative to the body comprising the two handle portions such that the output shaft can rotate to any desired angle relative to the handle portions, including in line with the first handle portion, in line with the second handle portion, midway between the handle portions, or at a position between the handle portions. The rotation mechanism allows the output shaft to rotate through an angle of more than 90 deg., preferably 120 deg. or more. The locking mechanism locks the output shaft in a desired rotational position.

In an illustrative embodiment, the motor is located in one handle portion and the battery (which may be rechargeable) is located in the other handle portion, so that the weight of the massager is balanced.

Exemplary embodiments of the invention will be further described with reference to the accompanying drawings, wherein like reference numerals refer to like parts. The figures may not be drawn to scale and certain features may be shown in generalized or schematic form and identified by commercial designations in the interest of clarity and conciseness.

Drawings

Fig. 1 is a perspective view of an impact type electric massager in accordance with an exemplary embodiment of the present invention, to which an extension handle is attached.

Figure 2 is an enlarged fragmentary view of the massager of figure 1 in the region where the extension handle engages one of the handle portions.

Figure 3 is an exploded view of the massager of figure 1 including an extension handle and an end cap for use when the extension handle is not present.

Figure 4 is a front view of the massager of figure 1 with the end cap installed in place of the extension handle.

Figure 5 is a cross-sectional view of the massager of figure 4.

Figure 6 is a partial perspective view showing the internal gearing and rotation mechanism of the massager of figure 1 and showing the most distal extension of the output shaft of the massager.

Figure 7 is the same view as figure 6 but showing the massager output shaft in its proximal most position.

Figure 8 is a front view of the massager of figure 4 but showing in phantom lines the different positions in which the output shaft may be rotated and locked.

Figure 9 is a front view of the massager of figure 4 showing the massager output shaft rotated such that it is in line with the longitudinal axis a1 of the first handle portion.

Figure 10 is a front view of the massager of figure 4 showing the massager output shaft rotated such that it is in line with the longitudinal axis a2 of the second handle portion.

Figure 11 is a front view of the massager of figure 4.

Figure 11A is a cross-sectional view of the massager of figure 11 taken along line A-A.

Figure 11B is a cross-sectional view of the massager of figure 11 taken along line B-B.

Fig. 11C shows two cross-sections of the overlap shown in fig. 11A and 11B.

Figure 12 is a partially exploded view of the massager of figure 4 showing the rotational locking mechanism in an exploded form.

Figure 13 is a non-exploded cross-sectional view of the massager of figure 12 showing the rotational locking mechanism in its locked position.

Fig. 14 is a non-exploded cross-sectional view of the massager of fig. 12 showing the rotational locking mechanism in its unlocked position.

Figure 15 is a rear view of a user using the massager of figure 1 according to a first possible use thereof.

Figure 16 is a rear view of a user using the massager of figure 1 according to a second possible use.

Figure 17 is a perspective view of the massage apparatus of figure 1 applied to a patient by a therapist according to a third possible use.

Figure 18 is a perspective view of a user using the massager of figure 1 according to a fourth possible use.

Figure 19 is a perspective view of a user using the massager of figure 1 according to a fifth possible use.

Figure 20 is a perspective view of a user using the massager of figure 1 according to a sixth possible use.

Detailed Description

Fig. 1 is a perspective view of an impact powered massager or simple "massager" 10 with an extension handle 15 attached, according to an exemplary embodiment. The massager 10 comprises a body 11 having a first handle portion 12 adapted and adapted to be gripped by a first hand of a user, a second handle portion 14 adapted and adapted to be gripped by a second hand of the user, and a central portion 16. The extension handle 15 is releasably attached to the second handle portion 14. At the output of the massager 10, a massage head 24 (such as a massage ball as shown) is secured to the distal end of the reciprocating output shaft 22. An output shaft 22 is guided within the conduit 20.

Figure 2 is an enlarged partial view of the massager 10 of figure 1 in the area where the extension handle 15 mates with the second handle portion 14. In this embodiment, a biased locking tab 18 on the extension handle 15 engages the second handle portion 14. When the user depresses the release button 52, the locking tab 18 disengages from the second handle portion 14 and the extension handle can be removed. Other mechanisms for releasably mating two components together are known and may be substituted.

Figure 3 is an exploded view of the massager 10 of figure 1 including the extension handle 15 and the end cap or cover 50 used when the extension handle is not in use. The releasable extension handle allows the user to quickly change the massager between the configuration shown in fig. 1 with the extension handle and the configuration shown in fig. 4 without the extension handle. As will be shown and described in greater detail later, the extension handle allows the user to effectively apply the massager to locations on his body that are not possible for the individual user to achieve, and allows the user to more easily and ergonomically reach other locations.

Figure 4 is a front view of the massager 10 of figure 1 with the end cap 50 installed in place of the extension handle. When the extension handle 15 is not present, the end cap 50 provides the massager with smoothly curved edges, thereby maintaining a clean and aesthetically pleasing appearance.

Figure 5 is a cross-sectional view of the massager of figure 4. The following components can be seen in this figure: a battery 30; an associated electrical ON/OFF switch 38; an electric wire 34; and an electric drive motor 36. The battery 30 is disposed in the first handle portion 12 and the electric drive motor 36 is disposed in the second handle portion 14. Herein, "disposed within" means at least partially disposed within. The battery 30 is preferably a rechargeable battery that can be recharged through a wired charging port (not shown) or a wireless charging system. Alternatively, the battery 30 may be a replaceable battery that is not rechargeable. The first handle portion 12 has a battery 30 therein, the second handle portion 14 has a motor 36 therein, and the central portion 16 has a gear assembly (fig. 6) therein, to balance the weight of the massager 10 on both the left and right sides. "balanced" may refer to the weight of the two handle portions, and thus the weight of the two sides, being within 5% of each other, or even within 10% of each other, or within 20% of each other.

The first handle portion 12 has a longitudinal axis a 1. Likewise, the second handle portion 14 has a longitudinal axis a 2. The reciprocating output shaft 22 extending from the central portion 16 of the body 11 has an associated reciprocating axis a 3. The output shaft 22 is operatively coupled to an electric drive motor to produce a linear reciprocating motion at the output shaft 22 and an impact massage head 24 fixed to the distal end of the output shaft 22.

The first and

second handle portions

12, 14 and their associated longitudinal axes a1, a2 define an obtuse angle that defines a minor arc (minor arc) α therebetween, and also defines a major arc (major arc) β the minor arc α defines an angle of less than 180 °, preferably less than 160 °, but greater than 75 °, preferably greater than 90 °, greater than 100 °, greater than 110 °, less than 130 °, more preferably the minor arc α between the first and second handle portions defines an angle of about 120 °.

Fig. 6 is a partial perspective view showing the internal gearing and rotation mechanism 40 of the massager of fig. 1 and showing the most distal extension of the massager output shaft 22. The rotation mechanism 40, which is of a hinge type, allows the output shaft 22 to rotate or pivot relative to the body 11 of the massager 10, including relative to the first and

second handle portions

12, 14.

The rotary mechanism 40 includes a generally circular inner housing or hub 42, which inner housing or hub 42 rotates within a generally circular outer housing or hub 43. The inner housing 42 is rotatably secured to the

handle portions

12, 14. The output shaft 22 is rotationally fixed to the outer housing 43 such that when the inner and outer housings are rotated relative to each other, the output shaft 22 rotates or pivots relative to the

handle portions

12, 14. The result is that the output shaft 22 can be rotated relative to the first and

second handle portions

12, 14 to a user selected angle.

A transmission mechanism housed within the inner housing 42 converts the rotational output from the motor 36 to a reciprocating output at the reciprocating output shaft 22 for operatively coupling the electric drive motor 36 to produce linear reciprocating motion at the output shaft 22, including at the distal end thereof. The transmission includes a first spiral bevel gear 44 and a second spiral bevel gear 45, the first spiral bevel gear 44 being directly coupled to the output of the motor 36, the second spiral bevel gear 45 meshing with the first spiral bevel gear 44. When bevel gears 44 and 45 rotate, crank pin 46 moves in a circular path as shown. The connecting rod 47 is connected to the crank pin 46 such that when the crank pin 46 moves along a circular path, the connecting rod 47 moves in a circular and reciprocating motion and the output shaft 22 driven by the connecting rod 47 moves in a linear reciprocating motion. Such transmission devices and mechanisms for converting a circular motion into a reciprocating motion are known per se. Additional details of mechanisms not shown or described herein will be apparent to those skilled in the mechanical engineering art.

Also visible in the figure is a shaft head 25 on the output shaft 22, which shaft head 25 has a spring-biased button 26. These features allow a variety of different massage heads (e.g., massage balls 24) to be easily installed on the massager 10 and removed to quickly and easily interchange massage heads in much the same way a socket is quickly and easily replaced on a socket wrench. Other mechanisms including other quick change mechanisms are also possible to allow for easy replacement of the massage heads.

Fig. 7 is the same view as fig. 6, but showing the massager output shaft 22 in its proximal most position. When the second spiral bevel gear 45 rotates, the output shaft 22 and the impact massage head 24 reciprocate, transmitting impact massage to the user.

Fig. 8 is a front view of the massager of fig. 4 but showing in phantom the different positions in which the output shaft 22 and the associated massage heads 24 can be rotated and locked. Five positions are shown showing the reciprocation axis A3 in five different orientations, namely A3, A3 ', A3 ", A3'" and A3 "". The mechanism may continuously pivot through this range of angles and, in the illustrative embodiment, may be locked into any of the five positions shown.

Figure 9 is a front view of the massager 10 of figure 4 showing the massager output shaft 22 rotated such that the reciprocation axis A3 is in line with the longitudinal axis A1 of the first handle portion. More generally, a1 and A3 are parallel and may be, but need not be, in-line. The output shaft 22 may be locked in this position.

Figure 10 is a front view of the massager 10 of figure 4 showing the massager output shaft 22 rotated such that it is in line with the longitudinal axis a2 of the second handle portion. More generally, a1 and a2 are parallel, but not necessarily exactly in line. The output shaft 22 may be locked in this position. Thus, the output shaft 22 and associated reciprocation axis A3 may be rotated more than 90, and preferably more than 100 and 110, and in this embodiment the full 120, to be parallel with either of the

handle portions

12, 14 and its associated axis A1, A2. Thus, when the extension handle 15 (fig. 1) is attached, the reciprocation axis a3 may form an acute angle of about 60 ° with the extension handle 15 as in fig. 9 if the extension handle is attached, or may be parallel to the extension handle 15 and in line with the extension handle 15 as in fig. 10.

Figure 11 is a front view of the massager 10 of figure 4. Figure 11A is a cross-sectional view of the massager of figure 11 taken along the line a-a and figure 11B is a cross-sectional view of the massager of figure 11 taken along the line B-B, the cuts being made at respective locations of the handle portions, i.e. at the same distance from the midpoint of the device and at the same distance from the respective distal ends of the

handle portions

12, 14. Figure 11C is a cross-sectional view of the massager of figure 11 showing sectional views taken along overlapping sectional views A-A and B-B. As can be seen in these figures, the circumference of cross section a of the first handle portion 12 is greater than the circumference of cross section B of the second handle portion 14. This difference in handle size allows users with different hand sizes to use primarily the handle portion that best matches their hand size. The difference in circumference may be greater than 10% and greater than 20% to ergonomically accommodate different sized hands.

Figure 12 is a partially exploded view of the massager of figure 4 showing the rotational locking mechanism 60 in an exploded form. Not explicitly shown in the figures is that a plurality of tooth portions 68, similar to teeth, are formed integrally with the housing cover 70 or are fixed to the underside of the housing cover 70. In the nominal state of the massager, the toothed sprocket 64 is biased upwardly against the sprocket retaining cap 62 by a spring 66. In this position, the teeth of the sprocket 64 engage at least a first tooth 68 on the massager body 11 and at least a second tooth 72 on the housing cover 70, wherein the first tooth 68 is rotatably coupled to the output shaft 22. In this position, the sprocket 64 rotationally locks the teeth 68 to at least the second teeth 72, thereby rotationally locking the output shaft 22 in a particular rotational position relative to the housing cover 70 and thus relative to the main body 11.

When the user presses the decorative cover 61 serving as the lock release button, the sprocket 64 is pressed against the spring 66, thereby compressing the spring 66. The sprocket 64 moves downward so as to no longer engage the teeth 72. In this position, the sprocket 64 and the tooth 68 are free to rotate relative to the tooth 72, and thus the output shaft 22 is free to rotate relative to the body 11. When the output shaft 22 is in the position desired by the user, the user releases the button 61, thereby locking the output shaft 22 in place. Other releasable locking mechanisms are also possible.

Fig. 13 is a non-exploded cross-sectional view of the massager of fig. 12 showing the rotational locking mechanism in its locked position (i.e., its non-depressed position). In this position, the teeth of the sprocket 24 mesh with the teeth 68 and 72, preventing rotation.

Figure 14 is a non-exploded cross-sectional view of the massager of figure 12 showing the rotational locking mechanism in its locked position (i.e., when the release button 61 is depressed). In this position, the sprocket 24 moves downward so that it engages the teeth 68, but not the teeth 72, allowing rotation.

Figures 15 to 20 illustrate the various uses of the device for impact massage of different parts of the body. It is believed that the use shown is not possible, or at least not easy, to achieve using any prior art impact massager.

Figure 15 is a rear view of a user using the massager of figure 1 according to a first possible use thereof. In this use, the pivoting mechanism is in its nominal position, such that the massager 10 has a Y-shaped configuration. The user 100 grips the first handle portion 12 with a first hand 101 and the second handle portion 14 with a second hand 102. As can be seen in the figures, the handle portion is angled so that the massager is adapted to be comfortably, naturally and ergonomically held by the first and second hands of the user while holding the impact powered massager to the user's back, particularly the user's lower back, while the impact massage heads 24 repeatedly strike the user's lower back muscles. Thus, the user can comfortably hold the impact massager 10 with both hands while delivering impact massage to himself by the reciprocating motion of the impact massage heads. In this position, the user can pull the device towards his back using a pulling motion that allows the user to pull the massager towards his back with a great force. This operation is optimal for delivering an impact massage to the back region near or adjacent to the spine.

Figure 16 is a rear view of a user using the massager of figure 1 according to a second possible use. The output shaft 22 of the massager 10 and the massage ball 24 connected thereto pivot such that the reciprocation axis A3 is in line with the longitudinal axis A1 of the first handle section 12, similar to the rotational position shown in FIG. 9. In this position, the user can use his left hand to pull the massager toward him with considerable strength while keeping it steady using his right hand and the extension handle 15. It is anticipated that this configuration will be used to provide a massage to portions of the back that are further from the spine than shown in fig. 15.

Figure 17 is a perspective view of the massager of figure 1 applied to a patient according to a third possible use by a therapist 110. The two handles allow the therapist to massage with great force and the relatively large distance between the positions where the therapist grips the device makes the stability more pronounced so that the massager 10 does not easily slide off its intended position and target site on the patient's body.

Figure 18 is a perspective view of a user using the massager of figure 1 according to a fourth possible use. Also, the two handles allow massaging with great force, and the wider handle distance provides stability.

Figure 19 is a perspective view of a user using the massager of figure 1 according to a fifth possible use. The acute angle between the output shaft 22 and the extension handle 15 enables a hooking action in which the user pulls the massager 24 on the extension handle 15 with his right hand towards the target position of his back, allowing the user to apply the massager against his back with considerable strength. In this position, the user may also use his left hand to help guide and stabilize the massager.

Figure 20 is a perspective view of a user using the massager of figure 1 according to a sixth possible use. The extension handle 15 allows the massage head 24 to reach areas of the user's body that would otherwise require more bending or twisting, including the calf muscles as shown and the sole of the foot.

Although not shown, the massager will also allow the user to sit to pull the impact massager 10 against the back of his thigh muscles with great force, providing results that were previously unattainable, or at least less easily accomplished.

Thus, the massager of the present invention provides the user with a multi-functional and ergonomic impact massage, which the user can use to more easily and stably and more powerfully deliver to various target areas on his body, as compared to prior art massagers.

It should be understood that the terms "generally," "approximately," "about," "substantially," and "parallel" as used in the description and claims herein are allowed to vary by any precise dimension, measurement, and arrangement, and these terms should be understood in the context of the description and operation of the invention disclosed herein.

All of the features disclosed in the specification, including the claims, abstract, and drawings, and all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

It is to be understood that the term "invention" as used herein is not to be interpreted as presenting only a single invention having a single basic element or group of elements. Similarly, it will also be appreciated that the term "invention" includes a number of individual innovations and features, which can each be considered an individual invention. Although the present invention has been described in detail with reference to the preferred embodiments thereof and the accompanying drawings, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. For example, the massager may include standard features of a variable speed motor and associated variable speed control. In addition, the massager may be modified to have a variable reciprocating stroke length. Still further, the massage may be operated on battery power and/or wall power (e.g., 120 VAC).

It is, therefore, to be understood that the detailed description and drawings, as set forth above, are not intended as limitations on the scope of the invention, which should be inferred only from the appended claims and their legal equivalents as properly interpreted.

Claims

1. An impact powered massager, comprising:

a body, the body comprising:

a central portion;

a first handle portion extending away from the central portion along a first axis, the first handle portion adapted to be grasped by a first hand of an operator; and

a second handle portion extending away from the central portion along a second axis such that an angle greater than 75 degrees and less than 180 degrees is formed between the first handle portion and the second handle portion, thereby defining a minor arc and a major arc between the first handle portion and the second handle portion, the second handle portion adapted to be grasped by a second hand of the operator when the operator grasps the first handle portion with the first hand of the operator;

a motor drive assembly at least partially disposed within the body, the motor drive assembly including at least an electric drive motor;

an output shaft extending from a central portion of the body within the major arc between the first handle portion and the second handle portion, the output shaft being operably coupled to the electric drive motor to produce a linear reciprocating motion at a distal end of the output shaft; and

a rotation mechanism that enables the output shaft to rotate relative to the first and second handle portions such that the impact massager is operable to deliver an impact massage when the output shaft is positioned at a user selectable angle relative to the first and second handle portions.

2. The impact powered massager of claim 1 wherein the rotation mechanism allows the output shaft to rotate more than 90 degrees.

3. The impact powered massager of claim 1 wherein the rotation mechanism allows the output shaft to rotate to a position parallel to the first said axis.

4. The impact powered massager of claim 1 wherein the rotation mechanism allows the output shaft to rotate to a position parallel to the first axis in a first position and allows the output shaft to rotate to a position parallel to the second axis in a second position.

5. The impact powered massager of claim 4 wherein the first position and the second position define an angle therebetween of greater than 110 degrees.

6. The impact powered massager of claim 1 further comprising a lock for locking the rotation mechanism in a desired rotational position.

7. The impact powered massager of claim 6 wherein the rotary lock comprises:

a sprocket with teeth;

at least a first tooth rotatably secured to the body;

at least a second tooth rotatably fixed to the output shaft;

a spring biasing the sprocket toward a position engaging the teeth;

a button coupled to the sprocket such that pushing the button causes the sprocket to resist the bias to disengage the sprocket from at least one of the teeth to allow the first and second teeth to rotate relative to each other;

thus, when the button is released, the bias moves the sprocket back into engagement with both the first and second teeth, locking the first and second teeth to each other in a fixed rotational position, locking the output shaft in a fixed rotational position relative to the main body.

8. The impact powered massager of claim 1 wherein the first handle portion has a first circumference at a first distance from the central portion along the first axis, the second handle portion has a second circumference at a second distance from the central portion along the second axis, and the first circumference differs from the second circumference by more than 10% to accommodate different sized hands.

9. The impact powered massager of claim 1 further comprising an extension handle releasably engaging at least one of the first handle portion and the second handle portion to provide a removable extension thereof.

10. The impact powered massager of claim 1 further comprising a battery located within the first handle portion and wherein the electric drive motor is disposed within the second handle portion.

11. An impact powered massager, comprising:

a central portion;

a reciprocating member extending from the central portion;

an impact massage head fixed to a distal end of the reciprocating member;

an electric motor operatively connected to the reciprocating member and driving the reciprocating member such that the reciprocating member reciprocates, the motion of the reciprocating member defining a reciprocation axis;

a first handle portion connected to and extending away from the central portion and a second handle portion connected to and extending away from the central portion such that the first handle portion, the second handle portion and the reciprocation axis define a Y-shape;

the first and second handle portions are adapted to be held by a first and second hand of a user while holding the electric impact massager on the user's back such that the impact massage head repeatedly impacts the user's lower back and such that the user can comfortably hold the impact massager with both hands while delivering an impact massage to himself through the reciprocating action of the impact massage head.

12. The impact powered massager of claim 11 wherein the first handle portion and the second handle portion define an obtuse angle therebetween.

13. The impact powered massager of claim 12 wherein the obtuse angle is greater than 100 degrees and less than 160 degrees.

14. The impact powered massager of claim 13 wherein the obtuse angle is greater than 110 degrees and less than 130 degrees.

15. The impact powered massager of claim 11 further comprising a hinge to which said reciprocating member is mounted such that said axis of reciprocation with respect to said first and second handle portions can be varied.

16. The impact powered massager of claim 15 wherein,

the hinge includes:

an outer housing; and

an inner housing rotating within the outer housing which is substantially circular; and is

Wherein the impact powered massager further comprises a gear converting a rotational motion from the electric motor into a reciprocating motion of the reciprocating member, the gear being received within the central portion.

17. The impact powered massager of claim 15 wherein the hinge allows rotation of the reciprocation axis through an angle exceeding 100 degrees.

18. The impact powered massager of claim 11,

the first handle portion and the second handle portion have different circumferences, whereby the first handle portion and the second handle portion are optimized to be gripped by hands of users of different sizes, respectively.

19. An impact powered massager, comprising:

a body, the body comprising:

a central portion;

a second handle portion extending away from the central portion, the second handle portion adapted to be grasped by a second hand of the operator when the operator grasps the first handle portion with the first hand of the operator;

an output shaft extending from the central portion of the body within an arc between the first handle portion and the second handle portion, the output shaft being operatively coupled to the electric drive motor to produce a linear reciprocating motion at a distal end of the output shaft, the linear reciprocating motion defining a reciprocating axis; and

an extension handle releasably engaging the first handle portion, the extension handle adapted to retain the impact massager via the extension handle when a user is using the impact massager to deliver an impact massage to himself.

20. The impact powered massager of claim 19,

the longitudinal axis of the extension handle defines an extension handle longitudinal axis, an

Wherein, the electronic massager of impact type still includes:

a rotation mechanism that enables the output shaft to rotate relative to the first and second handle portions to a position in which the reciprocation axis forms an angle of less than 70 ° with the extension handle longitudinal axis; and

an impact massage head attached to a distal end of the reciprocating member;

whereby a user may pull the impact powered massager through the extension handle to draw the impact massage head against the user's back.