GB2098059A

GB2098059A - Stopper for caster

Info

Publication number: GB2098059A
Application number: GB8201866A
Authority: GB
Original assignee: Sugatsune Kogyo Co Ltd
Current assignee: Sugatsune Kogyo Co Ltd
Priority date: 1981-03-09
Filing date: 1982-01-22
Publication date: 1982-11-17
Also published as: JPS57147948A; DE3204652C2; GB2098059B; DE3204652A1; CA1166805A; JPH0138681B2

Abstract

A stopper for a caster comprises a push-button 7 slidably received in a radial mounting bore 6 of a body member 1a, 1b, 1c (to which body the wheels 2 are journalled by way of an axle 3), and a rotatable pin 9 rotatably mounted transversely in the push-button: a spring 10 urging the push-button and pin radially outwards so that the ends of the pin engage in recesses 13 in the wheels to lock the latter; and cam profiles on both the central portion of the pin and the sides of the bore, whereby upon first depression of the push-button the latter is retained in a depressed position due to an interaction of the cam profiles, consequent upon partial rotation of the pin; and upon subsequent depression of the push-button further rotation of the pin allows it to return to its original position, with consequent re-application of the lock. <IMAGE>

Description

SPECIFICATION Stopperforcaster This invention relates to a caster and, more particularly, a stopper for a caster.

A conventional caster is mounted, for example, on each leg or the like offor example a chair our trolley and is thus used to facilitate the movement thereof.

The caster is conveniently provided to enable the chair etc to be stopped at a predetermined position and in a predetermined direction and a stopper unit may be provided for locking the caster wheel.

Stopper units of various types are already known, mostly employing a first button for applying the lock and a second button for releasing the lock. Thus, to lock the stopper a locking button is pushed against the elastic force of a spring to move the locking button and thereby engage the stopper with a recess or the like formed on the periphery of a wheel: to releasethe lock a lock releasing button is pressed to thereby disengage the spring and cause return movement of the stopper. Since the locking button and the lock releasing button are generally operated to lock or release the lock of the stopper with a leg in a parallel alignment, they entail such difficulties that the locking and the lock releasing operations are hardly conducted, and the selection of locking or lock releasing buttons can be easily mistaken.Inasmuch as the locking button is retained in a depressed position, there are the further drawbacks and disadvantages that its connector to the spring tends to wear, the lock can be easily released with a slight external force or vibration applied thereto, or its production cost is high owing to a large number of parts.

In accordance with this invention, there is provided a stopper for a caster, comprising a pushbutton slidably received in a mounting hole radially extending from the center of a frame for journaling at least one wheel of the caster, a stopper rotor rotatably mounted in said push-button, the pushbutton and stopper rotor being urged by a spring radially outwards for stops formed at the ends thereof to engage recesses in the wheel or wheels, said stopper rotor including an actuator intermediate its ends, and a cam groove formed in a wall of the push-button mounting hole and arranged to engage and hold the actuator of said stopper rotor so as to retain said push-button in its depressed position once it has been depressed to unlock the wheel or wheels.

An embodiment of this invention will now be described,by way of example only, with reference to the accompanying drawings, in which: Figure lisa plan view of a caster having a stopper in accordance with this invention; Figure 2 is a sectional view of the caster taken along the line ll-ll in Figure 1; Figure 3 is a sectional view of the caster p&commat; taken along the line Ill-Ill in Figure 2; Figure 4 is a side view showing the frame of the caster; Figure 5 is a sectional view of the caster taken along the line V-V in Figure 4; Figure 6 is a plan view showing the push-button and the stopper rotor; Figure 7 is a longitudinal sectional view of the stopper shown in Figure 6; Figure 8 is an enlarged sectional view of the stoppertaken along the line VIII-VIII in Figure 7; and Figure 9 is an explanatory view showing the relationship between the cam groove and the stopper rotor in operation of the stopper.

Reference is made particularly to Figures 1,2 and 4 showing one preferred embodiment of the stopper for a caster, like reference numerals being used in the drawings to designate the same or equivalent components and parts in other views.

In Figures 1,2 and 4, a caster 1 has a frame 1 integrally formed of an outerwall la of substantially semispherical shape in side view, a central boss lb and a middle wall ic connecting the outer wall la to the boss ib, wheels 2 and 2 rotatably supported at both sides of the frame 1 on an axle 3, and a mounting shaft4 disposed eccentrically to one side and rotatably supported through a bushing 5.

As shown in Figures 2 through 4, a mounting hole 6 is formed radially of the frame from its center and through the outerwall la and the middle wall ic, and a push-button 7 is slidably inserted into the mounting hole6.

As illustrated in Figures 6 and 7, spaced legs 7a and 7a project at both right and left lower sides of the push-button 7, and a stopper rotor 9 is rotatably inserted into holes 8 and 8 formed in the legs 7a and 7a.

As depicted in Figures 6 through 8, the stopper rotor 9 is formed with an actuator 9a at its middle, at both right and left of this actuator with bearings 9b and 9b of circular cross section, outwardly to one side with a flange 9c, outwardly to other side with an annular groove 9d, and at both right and left ends with flats 9e and 9e. The bearings 9b and 9b are rotatably received in the holes 8 and 8 of the pushbutton 7. The actuator 9a is disposed between the legs 7a and 7a. The flange 9c and a spring 10, engaged at one end with the annular groove 9d as shown in Figure 2, serve to prevent the removal of the stopper rotor 9 from the push-button 7.

As shown in Figure 8, the actuator 9a is shaped generally as a rectangle in cross-section, with its shorter sides formed with central recesses 9a' and Spa', leaving projections 9a" and 9a" at both right and leg sides thereof, end the actuator is rotatably guided within a cam groove 14 to be described in greater detail.

The spring 10 is engaged around a projection 11 formed on the middle wall Ic of the frame 1. and engages at its other end with a pawl 12 of the frame 1. The push-button 7 and the stopper rotor 9 are urged, bathe spring 10, radially outwards in the mounting hole 6. Thus, the flats 9e and 9e of the stopper rotor 9 are removably engaged with stopper recesses 13 formed in the peripheries of the wheels 2 and 2 to thereby lock the wheels 2 and 2. The pushbutton 7 may be moved (manually) radially inwards to move the stopper rotor 9 and disengage its flats 9e and 9e from the stopper recess 13 to thereby release the wheels.

The cam groove 14 is cut out of the middle wall lc of the frame 1 in the mounting hole 6, and the actuator 9a of the stopper rotor 9 engages within this cam groove 14.

As illustrated in Figure 9, the cam groove 14 is so formed that the width 1 of its opening 1 4a is substantially equal to or slightly greater than the short-axis width 1' of the actuator 9a. The opening 14a is formed at one side with a vertical edge 14b, the middle part of the cam groove is formed with a recess 14c, the other side of the opening 14a is formed with an oblique edge 14d inclined outwardly, and the lower side is formed of an upward step 14e. The actuator 9a is so formed as to be rotatably guided and to be engaged and retained stepwisely in its moving direction by the pushing operation of the stopper rotor 9 and the recoiling operation of the spring 10.

As depicted in Figures 4 and 5, ribs 15 and 15 are longitudinally formed at both sides of the cam groove 14. Thus, the legs 7a and 7a of the pushbutton 7 are engaged and guided between the ribs 15 and 15 so asto slide in a predetermined direction.

In the stopper thus constructed, the push-button 7 and the stopper rotor 9 are urged radially outwards by the spring 10. As shown in Figure 9, the actuator 9a is at this time located at the position A, oriented and retained with one of its long sides against the vertical edge 14b of the opening 14a of the cam groove 14, and the flats 9e and 9e are engaged in the stopper recesses 13 and 13 of the wheels 2 and 2 to lockthe latter.

When the push-button 7 is depressed against the force of the spring 10 from this locked state, the stopper rotor9 is similarly depressed (being carried by the push-button). Accordingly, the actuator 9a is depressed, from the position A shown in Figure 9, into the cam groove 14, but keeping its same attitude. As a result, the lower right side projection 9a" of the actuator 9a makes contact with the step 14e, and the actuator is accordingly rotated counterclockwise to the inclined position B shown in Figure 9.

When the depressing force of the push-button 7 is then released the push-button 7 is urged radially outwards again by the spring 10, and the actuator 9a is accordingly raised upwardly (in the cam groove), keeping the same attitude as that shown in position B in Figure 9. As a result, the upper left projection 9a" will make contact with the upper edge 14c' of the recess 14c. The stopper rotor 9 is then caused further rotation counterclockwise, and the projections 9a" along one long side ofthe actuator will make contact with the vertical edge 14b and the oblique edge 14d, and the actuator is thus retained at the position C with the stopper rotor still diesngaged from the wheel recesses 13.

When the push-button 7 is depressed from this lock-release state, the actuator 9a of the stopper rotor is lowered so that one side face thereof makes contact with the step 14e of the cam groove 14.

The actuator 9a is thus rotated toward the lower edge 14c" of the recess 14c disposed lowerthanthe step 14e and accordingly counterclockwise to the position D. When the push-button 7 is then released, the actuator 9a will rise and rotate to the original position and attitude A, but with the opposite side face of the actuator 9a in contact with the upper edge 14c' of the recess 14c. The flats 9e are now engaged again with the stopper recesses 13 to lock the wheels.

It should be understood that since the stopper lock or releases the wheels 2 and 2 merely by pushing a sole push-button 7, it improves the operability as compared with the conventional two-push-button type stoppers, and can also confirm the locked or lock-released state in accordance with the length of push-button 7 projecting from the mounting hole 6.

It should also be appreciated that since the stopper is constructed to retain itself in the lock-released state by the relative engagement of the actuator 9a of the stopper rotor 9 with the cam groove 14, it can be smoothly operated, and since the actuator 9a is located at the center of the stopper, the pressing force of the push-button 7 always urges the centre of the stopper rotor 9 and accordingly the locking and the lock releasing operations can be effectively conducted even with play between parts and with parts of irregular size.

It should also be understood that since the stopper consists of less parts than prior art stoppers (pushbutton 7, stopper rotor 9 and spring 10 in addition to the frame 1), it can be extremely simply constructed, and since the stopper rotor 9 can be inserted laterally into the holes 8 and 8 after the push-button 7 is inserted into the mounting hole 6, it can be more simply and inexpensively assembled than the conventional stopper.

Claims

1. Astopperfora caster, comprising a pushbutton slidably received in a mounting hole radially extending from the center of a frame for journaling at least one wheel of the caster, a stopper rotor rotatably mounted in said push-button the pushbutton and stopper rotor being urged by a spring radially outwards for stops formed at the ends thereof to engage recesses in the wheel or wheels, said stopper rotor including an actuator intermediate its ends, and a cam groove formed in a wall of the push-button mounting hole and arranged to engage and hold the actuator of said stopper rotor so as to retain said push-button in its depressed position once it has been depressed to unlock the wheel or wheels.

2. A stopper according to claim 1, wherein said stops are formed as flats at both ends of the stopper rotor

3. A stopper according to claim 1 or2,wherein said push-button comprises a pair of legs provided with holes in which said stopper rotor isjournalled.

4. A stopper according to claim 1,2 or 3, wherein said cam groove is formed in a middle wall of the frame.

5. A stopper according to claim 1, wherein said stopper rotor is formed with said actuator at its mid dle part, outwardly to both sides of the actuator with bearings of circular cross section, outwardly thereof to one side with a flange and to the other side with an annular groove, and at both ends thereof with flats, said bearings being rotatably received in holes of spaced legs of said push-button, said actuator being disposed between said legs of said pushbutton, and said flange and said spring (engaged at one end thereof with the annular groove) serving to prevent removal of said stopper rotor from said push-button.

6. A stopper according to any preceding claim, wherein said actuatorofsaid stopper rotor is mounted within the cam groove.

7. A stopper according to claim 6, wherein the cam groove has an opening substantially equal to or slightly wider than one cross-sectional width of the actuator of said stopper rotor, said opening being formed at one side with a vertical edge leading to a recess, the other side of the opening being an oblique edge inclined outwardly and the inner end of the groove being formed as an upward step.

8. A stopper according to claim 6, wherein longitudinal ribs are formed at both sides of the cam groove for engaging said push-button therebetween to slide in a predetermined orientation.

9. A stopper as claimed in claim 1, arranged so that re-application of the lock is achieved by redepressing said push-button.