Exercise device

An exercise device includes an elastic tube and a pair of elongate handles, each conveniently formed as a unitary member with no moving parts, integrally molded of a plastic. Each handle has a generally cylindrical outer surface and a pair of longitudinal slots formed internally of the outer surface in essentially spaced-apart, side-by-side relationship. The internal slots are dimensioned to grip the outer surface of the tube and have internal longitudinal ribs which enhance the gripping effect. A pair of transverse open-ended access slots are formed in the outer handle surface, each accessing one of the internal longitudinal slots to permit insertion and subsequent longitudinal displacement of the tube in the respective internal slot. An end of the tube is inserted transversely into one internal slot, wrapped through a 180 degree bend about a handle portion separating the internal slots, and then inserted transversely into the other longitudinal slot. Any tension in the elastic tube which initiates slippage of a tube end at one of the handles increases the frictional engagement of the tube end with the handle portion between the slots thereby increasing resistance to further slippage. The gripping action is sufficient that no additional clamping or holding mechanism is required to ensure that the exercise device does not come apart during use.

FIELD OF THE INVENTION 
The invention relates generally to exercise devices, and more specifically, 
to devices in which an elastomeric member is retained between a pair of 
handles for repeated extension. 
DESCRIPTION OF THE PRIOR ART 
Exercise devices which involve repeated extension of elastomeric members 
are known. They generally comprise a pair of handles which are attached to 
the elastomeric member to permit a user to conveniently grip the device. 
Such devices are less expensive than weights, rowing equipment or other 
exercise devices, and have the added advantage of portability, 
particularly if the handles can be conveniently disengaged from the 
elastomeric member. A principal concern in the design of such exercisers 
is to provide appropriate means for securing the handles to the 
elastomeric member. Since the active element of the exerciser is 
elastomeric in nature it cannot be gripped as readily and as positively as 
might, for example, an equivalent steel spring. The securing means must 
avoid any slippage or disengagement of the handles from the elastic 
member, as this might potentially injure a user, but cannot grip the 
elastomeric member in a manner which causes damage or significant wear in 
the elastic member. 
An early example of such an exerciser is described in Canadian Pat. No. 
275,216 which issued on Nov. 8, 1927 to Roy H. Noe. In that exerciser, 
ends of an elastic belt are essentially clamped to a pair of handles. Each 
handle has threaded studs and an associated clamping bar with clearance 
holes which permit the clamping bar to be fitted about the studs. 
Butterfly nuts threaded on the studs are suggested as appropriate means 
for squeezing the belts between the clamping bars and the handles. 
Another such exercise device is described in Canadian Pat. No. 368,113 
which issued on May 26, 1936 to William Shenk. In the Shenk device, the 
elastomeric member is in the form of an endless belt, and a pair of 
detachable handles are provided. Each handle has hinged semi-circular 
halves which can be wrapped about the belt and a pin which can be passed 
through aligned sleeves or passages when the halves are closed to secure 
the handle to the belt. 
Another exercise device involving an elastic cable is described in Canadian 
Pat. No. 1,153,032 which issued on Aug. 30, 1983 to Robert S. Hines. The 
cable is retained between a pair of handles each of which has a 
longitudinal hole and a pair of transverse holes positioned nearby. The 
gripping of the cable is said preferably to be achieved by passing an end 
of the cable through the longitudinal hole, then through one of the 
transverse holes and finally inserting the free cable end into the bight 
so formed. Such a device can be readily assembled and disassembled, but 
the hold which is maintained on the elastic member is not entirely 
satisfactory. There is a tendency in such devices for a handle to loosen 
suddenly from the elastic cable when tensioned with the attendant risk of 
a user striking himself. 
Exercise devices such as those described in the Noe and Shenk patents have 
handles which potentially grip an elastomeric member in a secure manner. 
However, these handles involve moving parts which add to the expense of 
manufacture and which are not particularly convenient for the end user. 
Handles such as those described in the Hines patent are entirely passive 
devices with no moving parts and consequently comparatively inexpensive to 
manufacture; however, there is some question whether such devices grip 
elastomeric members in a satisfactory fashion and a user consequently have 
some reluctance to use such a device. It would be desirable to provide an 
exercise device of the general nature described above in which handles can 
be conveniently and inexpensively constructed with no moving parts but 
grip an elastomeric member reliably without causing damage or undue wear 
to the elastomeric member. 
SUMMARY OF THE INVENTION 
In one aspect, the invention provides an exercise device comprising at 
least one elastomeric member and a pair of handles which can releasably 
attached to the elastomeric member. Each handle has an outer surface which 
is preferably elongate and generally cylindrical in shape. A pair of 
longitudinal slots are formed in the handle internally of the outer 
surface in substantially side-by-side relationship. A first open-ended 
slot is formed in the outer surface to permit access to one of the 
longitudinal slots for insertion of a section of the elastomeric member. A 
second open-ended slot is formed in the external surface to permit 
insertion of the elastomeric member into the other longitudinal slot. Each 
of the longitudinal slots is dimensioned to grip the elastomeric member 
when received. 
The elastomeric member is preferably in the form a length of hollow latex 
tube, although solid elastic cables and the like can be similarly retained 
by the handles. To attach the tube to one of the handles, a tube end 
portion is inserted through an access slot into one of the handle's 
longitudinal slots, wrapped about the handle structure separating the two 
longitudinal slots, and inserted through the other access slot into the 
handle's other longitudinal slot. The tube end is then gripped at two 
points along its length, and an intermediate section of the tube is 
wrapped about the handle portion separating the two longitudinal slots. 
The opposite tube end may be similarly retained by the other handle. Any 
tension in the elastic tube which initates slippage of a tube end at one 
of the handles increases the frictional engagement of the associated 
intermediate tube end section with the handle thereby increasing 
resistance to further slippage. The arrangement permits the construction 
of a handle which securely retains the elastic tube, which does not 
require any moving parts, and which can be designed, if desired, for 
convenient and inexpensive manufacture through injection molding. 
Various advantages of exercisers constructed according to the invention and 
components therefor will be discussed below in connection with a 
description of a preferred embodiment. A number of inventive features 
apparent from the preferred embodiment are more specifically recited in 
the attached claims.

DESCRIPTION OF PREFERRED EMBODIMENT 
Reference is made to FIG. 4 which illustrates an exerciser 10 comprising a 
latex tube 12 and a pair of elongate handles 14, 16 which serve to retain 
ends of the tube 12. In the orientation illustrated in FIG. 4, the handles 
14, 16 might be separated by a user horizontally to exercise his pectoral 
muscles. The exerciser 10 is illustrated in a generally vertical 
orientation in FIG. 3 where a pair of extension conduits or tubes 18, 20 
are shown attached to the handle 14, and another pair of extension 
conduits, 22, 24 are shown attached to the handle 16. In the orientation 
of FIG. 3, the upper extension tubes 18, 20 can be gripped by the user's 
hands and the lower extension tubes 22, 24 can be engaged by the user's 
feet to perform, for example, a curl exercise intended to develop a user's 
biceps. In practice, the lower extension tubes 22, 24 might be eliminated 
even for such exercises as the user can be many instances grip the handle 
16 directly with his feet. 
The handle 14 which is typical of both handles is illustrated in FIG. 1. 
The handle 14 is integrally molded of a plastic such as a polypropylene, 
and has a longitudinal axis 26 (in this case a central axi) and an outer 
or external surface 28 formed around the axis 26 and having a generally 
cylindrical shape. The handle 14 has three major components: a pair of 
opposing, generally cylindrical, end portions 30, 32 and a generally 
plate-shaped intermediate handle portion 34 joining the handle end 
portions. The intermediate handle portion 34 will be seen in FIG. 2 to 
have a pair of opposing, generally planar faces 36, 38, and a pair of 
opposing, generally planar side edge surfaces 40, 42. 
A first pair of longitudinally-directed fingers 44, 46 extend from the 
first handle portion 30 generally parallel to the intermediate handle 
portion 34. A similar pair of longitudinal fingers 48, 50 extend from the 
opposing handle portion 32 in similar relationship with the handle portion 
34. The two fingers 44, 48 (which are axially aligned) together with the 
face 36 of the intermediate handle portion 34 define a first longitudinal 
slot 52 positioned internally of the outer handle surface 28. The fingers 
46, 50 are spaced apart to define an open-ended transverse slot 54 in the 
outer handle surface 28 which accesses the interior of the longitudinal 
slot 52 and which is dimensioned to permit easy clearance of the tube 12 
(and also tubes of larger external diameter for purposes described more 
fully below). The pair of fingers 46, 50 on the diametrically opposite 
side of the handle 14 together with the intermediate handle portion 34 
similarly define another longitudinal slot 56, and between the fingers, a 
transverse open-ended slot 58 which accesses the longitudinal slot 56. It 
will be apparent that the longitudinal slots 56, 58 are essentially in 
side-by-side relationship, separated by the intermediate handle portion 
34. 
The structure of the handle 14 has been described in terms of a pair of 
distinct handle end portions, an intermediate handle portion and four 
fingers. These component have been viewed as defining the internal 
longitudinal slots and the access slots. The handle 14 may, however, be 
alternatively viewed as a generally cylindrical member in which a pair of 
longitudinal slots 52, 56 are formed internally of the outer surface 28 
and a pair of transverse open-ended slots 54, 58 are formed in the outer 
surface to access the two internal slots 52, 56. The slots may be viewed 
as defining the various handle structures such as the longitudinal fingers 
and the intermediate handle portion. It will also be appreciated that if 
the transverse access slots are positioned adjacent ends of the 
longitudinal internal slots only a single pair of fingers or equivalent 
structure will be defined. Such structure are regarded as falling within 
the ambit of the present invention, although the four finger arrangement 
is preferred as an additional elastic tube may be very conveniently 
retained, each under distinct fingers, to increase the force required to 
separate the handles without requiring a tube to be longitudinally 
displaced a great distance along the internal slots for proper retention. 
The manner in which the tube 12 is retained by the handles will best be 
understood with reference to FIG. 2. To arrive at the orientation 
illustrated in FIG. 2, the tube end portion 60 is first inserted through 
the access slot 54 into the interior of the longitudinal slot 52 and 
displaced axially to secure the tube end portion 60 between the finger 44 
and the face 36 of the intermediate handle portion 34. The tube end 
portion 60 is then wrapped about the intermediate handle portion 34, being 
bent through a full 180 degrees in the process, and then inserted in a 
similar manner through the other access slot 58 into the corresponding 
longitudinal slot 56 for retention under the finger 46. The spacing 
between the finger 44 and the face 36 of the intermediate handle portion 
(and also between the finger 46 and the face 38) is preselected to be 
substantially the difference between the outer and inner diameters of the 
latex tube (alternatively viewed, twice the tube wall thickness). 
Accordingly, the latex tube is snugly received between the finger 44 and 
intermediate handle portion 34 and compressed until substantially flat. To 
ensure positive gripping of the tube end portion 60, the finger 44 is 
provided with a longitudinal rib or tooth 62 which extends into the 
interior of the longitudinal slot 56 and the outer face 36 of the 
intermediate handle portion similarly defines a longitudinal rib 64, 
substantially coplanar with the rib 62. The other fingers and the opposing 
face 38 of the intermediate handle portion are similarly formed with 
longitudinal ribs that enhance gripping of the tube 12. To further enhance 
gripping of the tube, the side edge surfaces 40, 42 may optionally be 
formed with longitudinal ribs (not illustrated), at least one of these 
ribs being engaged with the exterior of the latex tube 12 at any time. 
A number of matters regarding gripping of the tube end portion 60 should be 
noted. First, as apparent in FIG. 2, the tube end portion 60 is gripped in 
both longitudinal slots 52, 56 thereby doubling the basic gripping force 
applied to the tube. Second, during normal extension of the tube 12 during 
exercise, any slippage apt to occur will first manifest itself at the 
finger 46 or alternatively viewed at the slot 56. This slippage increases 
the tension in the tube section between the fingers 44, 46 (wrapped about 
the intermediate handle portion 34) causing the tube section to engage the 
intermediate handle portion 34 more tightly. The tube section consequently 
applies a greater normal force into the side edge surface 40 of the 
intermediate handle portion 34 (and to some extent into the opposing faces 
36, 38 of the intermediate hand portion 34) thereby increasing frictional 
forces between the tube 12 and the handle 14 which tend to resist further 
slippage. It will be apparent that these frictional forces tend to 
increase in proportion to the amount of slippage occurring or the tension 
ultimately applied to the wrapped tube section, an effect contributing 
markedly to the positive retention of the tube 12. An additional factor 
resisting slippage is believed to be the manner in which the tube 12 is 
bent about the side edge 40 of the intermediate handle portion 34. It will 
be apparent from FIG. 2 that each of the side edges 40, 42 meets each of 
the opposing faces 36, 38 at substantially a right angle. This arrangement 
might be contrasted for example with the provision of semi-circular 
surfaces at the side edges of the intermediate handle portion 34. Slippage 
of the tube 12 relative to the handle 14 consequently requires significant 
and continuous deformation of the tube end 60 about the two right-angled 
corners 68, 70. Such deformation requires some force and accordingly 
resists slippage. It is not entirely certain to what extent this effect 
adds to the gripping provided by the handles. 
Although the handles 14 would be appropriate for retention of a solid 
elastic cable or one of irregular shape, the design of the handle 14 is 
singularly advantageous for use with a tubular elastomeric member such as 
the latex tube 12 which has predetermined inner and outer diameters. As 
mentioned above, the spacing between each of the handle fingers and the 
adjacent face of the intermediate handle portion 34 (the width of the 
associated longitudinal slot) is substantially twice the thickness of the 
tube wall (the difference between the outer and inner diameters of the 
tube 12 or twice the difference between the outer and inner radii). To 
increase the amount of force required to separate the handles 14, 16, it 
is only necessary to substitute a latex tube (assumed to be made of a 
similar material having the same Young's modulus) of larger outer 
diameter, but the same wall thickness. Such a tube may still be inserted 
snugly in each of the longitudinal slots 52, 56 and predictably retained, 
the tube simply expanding laterally more than the tube 12, but ultimately 
compressing in each longitudinal slot into a structure with a fixed 
thickness, twice the predetermined wall thickness. 
Optionally, retention of the tube end 60 may be further ensured by 
inserting a plastic plug 72 into its open end. The plug 72 (illustrated in 
FIG. 2) has a head 74 and a tapered shaft 76, which is thickest adjacent 
the head 74 (in excess of the inner diameter of the tube 12) and thinnest 
adjacent a free shaft end 78 (less than the inner diameter of the tube 
12). The shaft 76 is constructed as a number of separate disk-shaped 
members (such as the disk 80). These disk-shaped members tend to embed 
themselves in the internal surface of the tube 12 as the tube is stretched 
in response to slippage of the tube end portion 60 at the finger 44. 
tubing used to construct the extension tube 18. To further ensure proper 
seating of the extension tube 18 on the handle 14, paired recesses and 
O-rings may be provided in the handle end portion 30, although this 
arrangement has not be illustrated. An annular abutment shoulder 90 of 
slightly larger diameter than the cylindrical outer surface 82 of the 
handle end portion 30 ensures proper location of the extension tube 18 
relative to the handle end portion 30. 
Those skilled in the construction of such exercise devices will now be 
aware of the principal advantages of the exerciser 10. First, each handles 
may be conveniently and inexpensively constructed as unitary member by 
injection molding of a plastic. Second, no moving parts are required to 
ensure positive retention of the elastic tube 12, and the gripping 
arrangement will not stress the tube 12 at any particular point in such a 
manner as to cause premature wear of the tube. Third, the exerciser 10, 
including extension handles, can be conveniently disassembled and stored 
in compact form in a gym bag or the like. 
The handles of the exerciser might be constructed with only a single 
longitudinal slot and associated open-ended access slot. For example, with 
reference to the handle 14 of FIG. 1, the second longitudinal slot 56 and 
corresponding access slot 58 might be eliminated. The resultant handle 
would still be capable of retaining the tube end portion 60 and would 
represented a simple structure with no moving parts that could be readily 
molded as a unitary member of a suitable plastic. The twin longitudinal 
slot construction characteristic of the handle 14 is preferred as the 
principles of gripping inherent in such an arrangement (described above) 
provide for positive and reliable retention of an elastomeric member. A 
handle with three or more longitudinal slots each associated with an 
open-ended access slot might be considered, and would embody such gripping 
principles, but the twin slot arrangement is preferred for simplicity of 
molding and use. 
It will be appreciated that a particular embodiment of the invention has 
the tube end portion 60 and would represent a simple structure with no 
moving parts that could be readily molded as a unitary member of a 
suitable plastic. The twin longitudinal slot construction characteristic 
of the handle 14 is preferred as the principles of gripping inherent in 
such an arrangement (described above) provide for positive and reliable 
retention of an elastomeric member. A handle with three or more 
longitudinal slots each associated with an open-ended access slot might be 
considered, and would embody such gripping principles, but the twin slot 
arrangement is prefrred for simplicity of molding and use. 
It will be appreciated that a particular embodiment of the invention has 
been illustrated and that the extact features of this exerciser should not 
be regarded as restricting the scope of the invention or the appended 
claims.