referring first to fig1 , it shows in schematic form the overall organization . upper and lower bodies 100 and 101 have convex surfaces 100a and 101a to be hand grasped . the bodies are movable toward and away from one another , in directions indicated by arrows 102 . force is applicable as indicated by arrows f 1 and f 2 . a vertical guide 104 projects upwardly between the bodies from lower body 101 . it slidably guides in bore 105 in body 100 . an enlarged stop 106 on the guide is movable in bore 107 , and the stop engages upper body shoulder 108 to limit relative separation of the bodies . a spring , for example a compression spring 110 , extends between the bodies , and has an upper end that engages upper body shoulder 111 . the spring lower end 110a is carried by an adjuster 112 which has relatively long - lead , threaded engagement with body 101 , at 114 . ( one 360 ° turn of the adjuster lifts the spring lower end by amount x .) as the adjuster is rotated , the spring is tightened or loosened to vary the spring force acting to separate the bodies 100 and 101 . therefore , the amount of force f 1 and or f 2 required to urge the bodies relatively together may be adjusted . the user can determine the position of the adjuster , as by observing the rotary position of a marker 115 on the lower end of the adjuster . if desired , the adjuster rotary position can be electrically indicated as by on or off indication of leds 117 - 119 on body 100 . control of the leds is afforded by a potentimeter 120 and circuitry 121 . the potentimeter annular wiper 122 is carried by adjuster 112 , and vertical resistor 123 by upper body 100 . as the adjuster is rotated , the wiper moves upwardly or downwardly against the resistor , to vary the voltage input to circuit 121 , which in turn controls varied illumination of the leds , prior to urging of the bodies 100 and 101 toward one another . the extent of squeeze displacement of the bodies toward one another can also be detected , and indicated . note the contact 126 carried by the upper body for successive engagement with contacts 127 - 129 carried by the lower body 101 , contacts 127 - 129 arranged in a row in the direction of relative body movement . the intensity of illumination output of the leds can , for example be indicated , in response to such body movement and stepwise engagement of contact 126 with contacts 127 - 129 . annunciators can be substituted for the leds , to provide desired audible pulsing or vibration . elements 127 - 129 can be mechanical &# 34 ; click &# 34 ; producing , audible sounders , such as spring arms that are released to produce sound . referring next to fig1 - 4 , the exerciser 100 in its preferred form incorporates a longitudinally horizontally elongated upper handle part 10 extending parallel to , over , and spaced from a longitudinally horizontally elongated bottom handle part 11 , so that the two parts can be squeezed , one toward the other , for example vertically . part 10 has an elongated , upwardly convex surface 10a merging with side surfaces 10b and 10c , for ease of manual grasping , and a flat lower surface 10d facing lower part 11 . that lower part 11 is elongated beneath part 10 , and has a horizontally flat local upper surface 11a , and downwardly rounded , i . e . convex sides 11b and 11c . there are upwardly projecting longitudinally spaced end flanges 10e and 10f on upper part 10 , and longitudinally spaced downwardly spaced end flanges 11e and 11f on lower part 11 . these provide device support surfaces as at 10g and 11g , and which are downwardly flat . a bottom 11d &# 39 ; between end flanges 11g is shown and is downwardly convex , for ease of hand grasping . opposite ends of bodies 10 and 11 appear at 10h and 10i , and 11h and 11i . the force f ( squeeze ) with which the top part 10 is forced toward the bottom part 11 is the force exerted by the operator . ( note that directional words &# 34 ; top , bottom , up , down , left , right &# 34 ; are used here to clarify the figures , not to indicate a preferred orientation of use .) a slide 12 is movable longitudinally left or right in a body recess 13 , by the operator , to select relative to scale 14 the desired value of f where feedback to the operator occurs . note slide marker 12a , and a block 83 connected to the slide to vary the effective length of a cantilever spring beam 28 . the flat bottom surfaces 11g of flanges 11e and 11f facilitate use when the force relates to that occurring when the human user pushes down on 10 while 11 is set against a flat surface . when the exerciser is used for squeezing by a hand , the hand ( either palm or finger ) fits on the curved , downward convex bottom 11d &# 39 ; between the square end flanges , and also over the upward convex top 10a , i . e . the device is hand held . fig4 and 7 show the interconnection and operation of the parts . the moving levers 15 and 16 pivot about fulcrums 17 and 18 on the top surface 11a of lower part 11 . the pushers 22 and 23 on upper part 10 move downwardly onto lever extensions 24 and 25 carried by levers 15 and 16 , and thereby transmit force from 10 to the ends of levers 15 and 16 , which are upwardly and downwardly movable with part 10 . at 26 and 26a the overlapping other ends of the levers , the force on each lever has been substantially reduced , as for example by a factor of 8 to 10 , and the vertical motion increased correspondingly , because of the proportions of the levers . a short wire 27a is loosely held in holes at the lever ends 26 and 26a so that the vertical force on a tab 27 is the sum of the vertical forces exerted by levers 15 and 16 where they overlap . the distance that tab 27 moves up is that amount permitted by restraining cantilever beam 28 mounted to part 10 at 21 as shown . tab 27 and beam 28 may consist of a spring wire , configured with a u - bend as shown . as selector slide 12 is moved left and right , the spring characteristic of cantilever restraining beam 28 is modified because the effective length of the free bending part of the restraining beam is altered . thus , the slide is operatively and variably coupled to 28 . when the restraining beam 28 is moved up by the levers to cause a contact 27 on lever 15 to touch the electric contact 27a on part 10 , an electric circuit connects the batteries 30 to a motor 31 . rotation of an eccentric weight 31a on the shaft of 31 causes a vibration throughout the exerciser , as readily felt by the operator , i . e . indicated , until the squeeze force is decreased enough to disconnect the contact at 27a . note that with the geometry as shown , the summing of forces by the linked levers 15 and 16 causes the completion of the electric circuit for a specific position of slide 12 wherever the forces are applied to 10 : left end of 10 , right end of 10 , or distributed across 10 , as long as the positions are no further out than shafts 22 and 23 . fig2 shows use of guides 81 , like guide 104 in fig1 . parts 10 and 11 are hollow , to contain the mechanism shown . fig1 shows another way to move a force sensor 32 ( affixed to a top body 33 ) downward to where it contacts a bottom body 34 when the selected compressive force i . e . squeeze is applied to 33 and 34 . flexible cantilever arms 35 and 36 are rigidly mounted at their right ends to lower body 34 . when adjustment knob 37 is turned , the attached screw 38 , through nut 38a affixed to upper body 33 , moves body 33 with its contact pawls 39 to the right , where a greater force is required to be exerted via supports 39 to bend spring beams 35 and 36 enough to allow 32 to touch 34 . the scale marks at 111 on body 33 , that line up against the indicator arrow 112 on 34 , are positioned by calibration , to show the applied force needed for contact . fig1 shows a symmetrical alternative to fig1 . instead of moving the top body 45 left and right along or lengthwise of the bottom body 46 , the pawls contact the flexible lever arms 113 and 114 ( extending oppositely ) closer to or further from their rigid supported ends , and thus change the effective force vs vertical distance sensitivity of the force sensor . in fig1 the pawls 41 and 42 are moved symmetrically oppositely toward or away from the center by rotating knob 43 that connects to the long screw 44 that has clockwise threads on its left half to move pawl 41 , and anti - clockwise threads on its right half to move pawl 42 . the position of one or both pawls on upper body 45 can be seen from the outside , and correspond to a particular sensitivity for the force required to make the force sensor operate . note that the principles behind the fig1 and 17 units are that the relationship between the applied force and the vertical displacement of the force sensor 32 is varied by the position variation of the pawls along the flexible arms , such as 35 and 36 . by way of contrast , in fig1 - 4 , the two beams or levers 15 and 16 amplify the downward motion transmitted by the upper body 10 as it descends toward the lower body 11 to become a much larger vertical motion exerted against beam 28 . there are two advantages : displacement of the sensor is increased so manufacturing tolerances become less tight , and the force on slender beam or arm 28 is much less then the direct pawl forces on the rugged flexible arms of fig1 and 17 , and so there is less danger of permanent set of the flexible arm or beam 28 . also shown in fig2 are vertical guide or guides 80 and 81 to guide relative movement of bodies 10 and 11 . fig3 and 8 show sliding at 84 of block 83 along the beam 28 . fig5 and 6 show frictional sliding of a bowed part 86 associated with block 83 , and connection at 89 to the slide 12 , to locate the slide and block , at selected positions . fig9 and 10 show optional use of a second beam or wire 28a operatively connected to the slider block 83 and optionally connectible to the levers 15 and 16 . therefore , if a stepwise greater spring resistance to closing together of the parts 10 and 11 is desired , wire 28a is rotated about its axis as by a bent end 28aa of that wire , to bring arm 28aa &# 39 ; of the wire into slots 89 in the ends 26 and 26a of the two levers . now both wires 28 and 28a resist upward deflection of the lever ends . bent end 28aa may protrude at the rear wall 10h , for rotation between positions a and b , as indicated . fig1 shows an alternate form of the device in which one elongated spring arm 120 is substituted for levers 15 and 16 . arm 120 has downward protrusions at 121 and 122 to engage the bottom part 11 at 121a and 122a , and upward protrusions 123 and 124 to engage the upper part 10 at 123a and 124a . as upper handle part 10 is pushed downwardly , the arm 120 flexes downwardly at 125 and 126 , and upwardly at mid - extent 127 , where a strain gauge ( as represented at 160 ) may be employed , with output connected to 130 ( see below ). alternatively a contact 128 on 127 may be used to engage contact 129 on upper part 10 , causing circuitry 130 to activate an annunciator or vibrator 131 as referred to above . fig1 shows three different contacts 140 - 142 to be successively engaged by a contact 143 , as the parts 10 and 11 move relatively together . ( see in this regard , fig1 , contacts 127 - 129 engagable by contact 126 , to offset output .) fig1 is a circuit diagram as also seen in fig1 . fig1 shows two clips 54 and 55 that fit snugly on the flange portions 11e and 11f of the bottom body 11 of the inverted unit as seen in fig1 . strap 56 is connected to the clips via strap extensions 56a and 56b . by holding a foot 57 on the loop 57a at the bottom of strap 56 , the upward force exerted by hand 113 &# 39 ; on body 10 can be applied at a convenient location i . e . 10 and 11 can be swung to alternate positions at seen at 10 &# 39 ; and 11 &# 39 ;. strap 56 can be flexible or non flexible . fig1 a shows a modification in which ears 11e &# 39 ; and 11f &# 39 ; are provided on 11e and 11f , to support flexible lines 56a &# 39 ; and 56b &# 39 ; corresponding to 56a and 56b in fig1 , simplifying the arrangement , as by eliminating need for clips 54 and 55 and straps 56a and 56b . fig1 a - 15c clarify and depict typical uses to which the isometric experience can be put . fig1 a shows the bottom part 11 of the exerciser 100 mounted on a carrier 120 so that the user can squeeze body parts 10 and 11 via the carrier , as via squeeze force application shown at f 2 and f 3 . the carrier can , for example be one of the following : i ) a steering element 150 &# 39 ; of a craft such as a vehicle , boat , aircraft , etc . ii ) a briefcase strap , as seen at 151 &# 39 ; in fig1 c iii ) the handle 152 &# 39 ; of a tennis racket , as seen in fig1 b v ) a headrest ( in which case f 2 represents head force , the carrier being fixed ). the exerted force can be a function of velocity of upward pull , i . e . f = f ( v n ), where &# 34 ; n &# 34 ; is a variable determined by the mechanism . for example , a device such as a roller may be interposed between strap 56 and loop 57 , with a return spring attached to the roller . see elements 160 , 56 &# 39 ; and 57 &# 39 ;. fig1 shows use of the device 100 in a warning system indicated at 150 , in block diagram form . a user 151 , such as a vehicle driver , has his hand in a position to squeeze the device 150 . that device is adjusted to effect production of a warning signal , indicated at output 152 , if the user fails to exert sufficient squeeze force after a suitable time interval , say five seconds . if he does not exert sufficient squeeze force , no warning is produced , as indicated at 153 . an input signal is provided or generated at 154 . that signal may for example be an audible &# 34 ; beep &# 34 ; produced at repetitive intervals , say every six seconds . thus , the sleepy operator is reminded to squeeze the device every six seconds at a squeeze force level consistent with being awake . if he fails to do so , a loud warning is produced , as at 152a to awaken him . fig1 a shows a circuit to provide the fig1 functions . when signal generator 154 provides an audible beep signal to the user 151 , it also sends a pulse at 156 to a delay circuit 157 . after a time interval t , say six seconds , delay circuit 157 sends a pulse on line 158 to activate the warning producing device 152a . a switch 159 in line 158 can be opened by squeezing of device 150 above a selected squeeze force level . if the user fails to sufficiently squeeze device 150 , switch 159 is not opened , and the warning is produced , at repetitive intervals t . small , fits in pocket or purse so user always has close access to device , with convenience of not having to go to an exercise facility ; device can be the handle of a briefcase , to give the traveling user an exercise opportunity ; device is adaptable to a vehicle steering wheel , a tennis racket handle , and to a neck rest in a vehicle . user has many feedback options : sound , light , telemeter signal to a tv at which user is already looking , vibration ( or jolt or sudden slip ); exercise involves at least one user &# 39 ; s body part touching the device , and therefore the vibration feedback can always be detected by that body part ; note that simple vibration is quieter than audible sound , and thus less annoying to others . ( vibration is of course always related to some sound .) provision for many mechanism options : springs , levers , on - off switch , strain gauges ; more sophisticated electronics can for example give a special identity to the tenth repetition at one strength setting , ( such as stronger vibration , or rapid on - off - on - off - etc .). the device can be combined with a pull cord whose rate of pulling determines its force level as referred to in fig1 ; i . e . f = f ( v n ). the device itself can be the puller handle . the user pulls at a rate that resists the pull at the device force setting . this simple mechanism can substitute for weight lifts ( mechanism held down by user &# 39 ; s foot ) or weight pull down ( mechanism bracket attached to top of a door ). a curtain roller is a good starting point . many feedback options , beside on - off . for use with a tennis racket , device is &# 34 ; off &# 34 ; when zero or small force is applied ; full on when inadequate force is applied ; zero again when force is correct . for basic exerciser , 400 hz pulses can start at 80 % of a selected force , with a pulse on 0 . 1 sec ., off 0 . 9 , or 0 . 1 sec ., etc . at 88 % attainment of selected force , a pulse is on 0 . 5 sec ., off 0 . 5 sec . ; at 96 % of exertion force , device is on continually ; above 100 %, vibrator operates at 800 hz , and above 104 % vibration interrupted every 1 second as , with the 80 % to 96 % realm but now with shorter &# 34 ; on &# 34 ; periods . no signal provided above 120 or 125 %. this is by way of example , only . force selection can be made by push button or other device ; an output display can be alphanumeric , or by means of length of an electronic bar display . for the unit connected to the electric cable , for some exercises , the cable can be non - elastic ( standard rope or cord ). the unit rounded shape is comfortable to hold or to press one side against a human body / arm / leg / or other internal or external surface . flat sections or flanges at opposite ends stabilize the unit when it is pressed against a flat surface such as a wall or table . the flat sections may be omitted . an alternative would be to eliminate the flats at each end , and to flatten the base ( underside ) of the oval cross - section to permit stable pushing against a flat surface . the squared ends provide a convenient structure onto which to clip the ends of an elastic cord that sometimes is employed during exercising . other simple attachment options are available . there can be multiple scales or ranges for the selected forces on the exerciser . there can be supplementary equipment such as a stretchable cord whose ends clip onto an exerciser that provides a resistive force against which the device , as a &# 34 ; handle &# 34 ;, is moved . the exerciser can be built into the steering wheel of a car so that exercises can be conducted while driving : hand squeezes of the two units on the right and left segments of the steering wheel ; compression or separation forces between the two units . note that the hands must be firmly holding onto the steering wheel for this application , for applying the forces and receiving vibration feedback -- and the firm grip can improve driving safety . exercisers can also be integrated into the car seat or headrest , to quantify other in - car exercises . there are also various approaches to the technical specifics of the device . it is important that the compressive force be sensed accurately wherever it is applied laterally along the device . linkages bring the applied force to a common point where the sensing takes place ( or , more expensive , multiple sensing at the periphery is summed ). the simple device employs two levers that meet in the middle of the unit where the compressive forces from the ends are summed ( after being decreased by , say 10 times ). the force is monitored by the displacment at the center against a spring . the spring tension is typically adjustable , in a non - linear manner , by the spring being a wire or beam whose effective length is adjusted by a slide guide . ( the amount of non - linearity is readily adjusted by adjusting the percentage of wire length through which the slide moves . the force for a specific deflection of the beam end varies as the cube of beam length . decreasing the beam length by 50 % gives a convenient non - linearity . to have a desirable long slide adjustment results in a long wire , but the free end is doubled back to reach the swing point and so the overall length is left small enough to fit in the unit .) instead of a two - lever system a single sensing bean connecting to the two ends can be used , with a strain gauge at mid - beam sensing the summed loads from each end . ( actually , the strain gauges are used , one above and one below the beam , to compensate for temperature effects .) the strain gauge output can be compared against the output of a user adjustable resistor ( conveniently built into one end of the unit ) calibrated so the selected force is indicated by position of a knob . the resistor can be a non - linear type . with a more flexible beam , the single beam approach can be substituted for the two levers of the simple or reference device . referring again to fig8 and 11 , the circuitry shown at 121 and 131 may include pulse producing circuitry operable to produce a series of detectable pulses which have durations that increase or decrease as the amplitude of squeeze increases . such pulse durations may have maximum duration when a predetermined threshold level of squeeze is exerted . each pulse may comprise a series of vibrating oscillations at a first predetermined frequency f 1 . i ) a first group of pulses each of which comprises a series of vibrating oscillations at a first predetermined frequency f 1 the pulses of this first group having maximum duration when a predetermined threshold level of squeeze is exerted , and j ) a second group of pulses each of which comprises a series of vibrating oscillations at a second predetermined frequency f 2 , the pulses of the second group produced only after said squeeze exceedsd the threshold level .
a squeezable exerciser comprising in combination body structure having surfaces to be squeezed relatively toward one another by application of force exerted by a user , and means associated with the body structure to produce a reference signal or signals as the level of force application reaches a preset limit or limits .