EP1690477A1 - Carpet stretching device - Google Patents

Abstract

A carpet stretching device (2) includes a housing (4), a piston unit (5), a carpet gripping head (6) connected to the housing (4), a fluid supply unit (7) connected to the housing (4), and an anchor member (522). The housing (4) has front and rear ends (421, 422), and a receiving space (41) between the front and rear ends (421, 422). The piston unit (5) includes a piston member (51) disposed in the receiving space (41) for moving relative to the housing (4), a piston rod (52) extending out of the housing (4) through the front end (421), and a biasing member (54) provided between the rear end (422) of the housing (4) and the piston member (51). The anchor member (522) is attached to a front end (521) of the piston rod (52) in front of the carpet gripping head (6).

Description

• The invention relates to a carpet stretching device, more particularly to a carpet stretching device that can stretch a carpet tightly and smoothly on the floor.
• Referring to Figure 1, a conventionalcarpet stretching device 1 includes an elongatedmain body 13 having one end connected to acarpet gripping head 14, and the other end connected to aknee plate 15. Thecarpet gripping head 14 includes a plurality of forwardly extendingspikes 141 disposed on a bottom portion thereof. Thecarpet stretching device 1 is operated by placing thecarpet gripping head 14 on the floor such that thespikes 141 engage thecarpet 11 near the edge thereof.
• In use, an installer holds down thecarpet gripping head 14 with his/her hand, and repeatedly strikes theknee plate 15 with his/her knee, so that thecarpet 11 is urged toward awall 12, after which thecarpet 11 is fixed on thewall 12.
• Although the conventionalcarpet stretching device 1 can achieve its intended purpose, much time is consumed in performing stretching of theentire carpet 11. Furthermore, since the installer has to repeatedly strike theknee plate 15 with his/her knee to urge thecarpet 11 to thewall 12 as described above, the installer may injure his/her knee over time. Moreover, since the striking force on theknee plate 15 may differ for each strike, thecarpet 11 may not be evenly stretched on the floor, thereby adversely affecting its final appearance.
• Therefore, the object of the present invention is to provide a carpet stretching device that can enable an installer to easily and quickly stretch a carpet on the floor.
• According to one aspect of this invention, a carpet stretching device comprises a housing, a piston unit, a carpet gripping head connected to the housing, a fluid supply unit connected to the housing, and an anchor member. The housing has a front end, a rear end, and a receiving space between the front and rear ends. The piston unit includes a piston member disposed in the receiving space for moving relative to the housing, a piston rod extending out of the housing through the front end, and a biasing member provided between the rear end of the housing and the piston member. The anchor member is attached to a front end of the piston rod in front of the carpet gripping head.
• According to another aspect of this invention, a carpet stretching device comprises a housing, a handgrip connected to the housing, apistonunit, a carpet gripping head, an anchor member, and a fluid supply unit. The piston unit includes a piston member movably disposed within the housing, and a piston rod connected to the piston member and extending out of the housing. The carpet gripping head is connected to one of the housing and the piston rod. The anchor member is attached to the other one of the housing and the piston rod. The fluid supply unit includes a main supply passage provided in the handgrip, a main valve assembly provided in the handgrip and controlling the main supply passage, an auxiliary passage connected fluidly to the main supply passage and the housing, and a safety valve assembly for controlling the auxiliary passage.
• Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
• Figure 1 is a schematic side view of a conventional carpet stretching device in a state of use;
• Figure 2 is a perspective view of the first preferred embodiment of a carpet stretching device according to the present invention;
• Figure 3 is an exploded perspective view of a carpet gripping head and a cover plate of the first preferred embodiment;
• Figure 4 is a sectional view of the first preferred embodiment;
• Figure 5 is a view similar to Figure 4, but illustrating the first preferred embodiment in a state of use;
• Figure 6 is a sectional view of the second preferred embodiment of a carpet stretching device according to the present invention;
• Figure 7 is a sectional view of the safety valve assembly, illustrating how a fluid flows through a first valve channel;
• Figure 8 is a view similar to Figure 7, but illustrating how the fluid flows out of the safety valve assembly to the atmosphere; and
• Figure 9 is a view similar to Figure 6, but illustrating the second preferred embodiment in a state of use.
• Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
• Referring to Figures 2 to 4, the first preferred embodiment of acarpet stretching device 2 according to the present invention is shown to comprise ahousing 4, apiston unit 5, acarpet gripping head 6, afluid supply unit 7, and a knee-applyingcushion member 8.
• Thehousing 4 has anopen front end 421, a closedrear end 422, areceiving space 41 between the front andrear ends 421, 422, and acover plate 43 fastened to thefront end 421 of thehousing 4 to cover thereceiving space 41. Thecover plate 43 includes anannular protrusion 434 projecting outwardly from afront face 432 of thecover plate 43 at a central portion thereof and having a throughhole 431, and two rows ofteeth 433 formed respectively on two opposite sides of theannular protrusion 434.
• Thepiston unit 5 includes apiston member 51, ahollow piston rod 52, aninsert rod 53, and abiasing member 54. Thepiston member 51 is disposed within thereceiving space 41 for moving relative to thehousing 4. Thepiston rod 52 has afront end 521, and arear end 520. Thefront end 521 extends through thepiston member 51, thefront end 421 of thehousing 4 via the throughhole 431 in thecover plate 43, and out of thehousing 4. Theinsert rod 53 has one end connected to therear end 520 of thepiston rod 52, and the other end connected fixedly to therear end 422 of thehousing 4. Theinsert rod 53 is extendable into thepiston rod 52 when thepiston member 51 moves toward therear end 422 of thehousing 4, and has a hexagonal cross-section to prevent rotation of thepiston rod 52 when thepiston member 51 moves relative to thehousing 4. Thebiasing member 54 includes a coiled spring extending around theinsert rod 53, and has two opposite ends abutting respectively against thepiston member 51 and therear end 422 of thehousing 4.
• Thecarpet gripping head 6 is connected to thecover plate 43 of thehousing 4. Thecarpet gripping head 6 includes a hollow pin-holding seat 612, and an upright connectingportion 611 connected fixedly to the pin-holding seat 612. The pin-holding seat 612 includes a plurality of forwardly extendingshort pins 622 disposed on a bottom portion thereof in a conventional manner, and anoperating unit 64. Theoperating unit 64 includes aflat plate portion 641 located within the pin-holding seat 612, and arotatable knob 642 connected to theflat plate portion 641 and located outwardly of the pin-holding seat 612. Theflat plate portion 641 is provided with a plurality of forwardly extendinglong pins 621 that extend from a bottom portion thereof. Therotatable knob 642 is operable so as to extend or retract thelong pins 621 out of or into the pin-holding seat 612.
• The upright connectingportion 611 of thecarpet gripping head 6 is substantially U-shaped, and is connected detachably to thefront face 432 of thecover plate 43. Twoopposite arms 613 of the connectingportion 611 are respectively formed withelongated slots 614. Each of thearms 613 has a connecting face formed with a row ofteeth 615 that meshes with the corresponding row ofteeth 433 on thefront face 432 of thecover plate 43.
• When theconnecting portion 611 is connected to thefront face 432 of thecover plate 43, theannular protrusion 434 of thecover plate 43 extends between thearms 613 of theconnecting portion 611. The height of the pin-holding seat 612 relative to thecover plate 43 is adjusted by changing the position of theteeth 615 on thearms 613 of the connectingportion 611 relative to theteeth 433 on thecover plate 43. After the pin-holding seat 612 is adjusted to a desired height, twoscrews 63 are respectively passed through theelongated slots 614, and engage threadedly thecover plate 43 so that thecarpet gripping head 6 is secured to thecover plate 43.
• Ananchor member 522 is attached to thefront end 521 of thepiston rod 52 in front of thecarpet gripping head 6, and is formed with a trapezoidal through hole 523 (see Figure 2).
• Thefluid supply unit 7 is connected to thehousing 4, and includes amain supply passage 711 provided in ahandgrip 71, amain valve assembly 712, and amain trigger 72. Thehandgrip 71 is connected to thehousing 4, and is adapted to connect with a power source, such as a high-pressure gas pump (not shown). Themain supply passage 711 is provided in thehandgrip 71, and is in fluid communication with thereceiving space 41. Themain valve assembly 712 is provided in thehandgrip 71 to control a supply of fluid through themain supply passage 711. Themain trigger 72 is connected to themain valve assembly 712 for controlling the same.
• The knee-applyingcushion member 8 is provided on therear end 422 of thehousing 4.
• Referring to Figure 5, in combination with Figure 4, prior to laying of acarpet 3 on thefloor 9, afoam layer 91 is first adhered to thefloor 9 in a conventional manner, and aretaining unit 92, such as a tack strip, is fixed at a suitable location of thefloor 9 for anchoring of theanchor member 522. When thecarpet 3 is to be stretched toward awall 12, thecarpet gripping head 6 is first secured to thecover plate 43 of thehousing 4 after the height difference between thecarpet gripping head 6 and thecover plate 43 is decided and after taking into account the thickness of thecarpet 3. Next, therotatable knob 642 is operated so as to extend thelong pins 621 out of the bottom face of the pin-holding seat 612 and pierce through thecarpet 3. Theanchor member 522 is then anchored to theretaining unit 92 so that theshort pins 622 pierce through thecarpet 3. Afterwards, the installer grasps thehandgrip 71, and operates themain valve assembly 712 by pressing themain trigger 72 so as to permit flow of fluid through themain supply passage 711 into thereceiving space 41 so that thepiston member 51 is activated.
• With reference to Figures 4 and 5, the power source functions to introduce a high-pressure gas through themain valve assembly 712 and themain supply passage 711 and into a first receivingportion 411 of thereceiving space 41 that is proximate to thefront end 421 of thehousing 4 and a second receivingportion 412 of thereceiving space 41 that is proximate to therear end 422 of thehousing 4. When the air pressure in the first receivingportion 411 is larger than the air pressure in the second receivingportion 412, thepiston member 51 is pushed toward therear end 422 of thehousing 4. However, in this embodiment, since thefront end 521 of thepiston rod 52 is anchored to the retainingunit 92 through theanchor member 522, thepiston member 51 cannot move toward therear end 422 of thehousing 4. Instead, thehousing 4 is moved toward the direction of the retainingunit 92 so that the distance between thepiston member 51 and therear end 422 of thehousing 4 is reduced. Simultaneously, the biasingmember 54 is compressed and stores a force, and thecarpet gripping head 6 moves toward the direction of the retainingunit 92. The installer may strike thecushion member 8 with his/her knee, thereby achieving the purpose of stretching thecarpet 3. During the stretching operation, crimping of the edges of thecarpet 3 may occur. The crimped edges of thecarpet 3, if produced, can extend through thetrapezoidal hole 523 in theanchor member 522, thereby preventing thecarpet 3 from being pinched in the area of theanchor member 522.
• When themain trigger 72 is released from its depressed position, the power source cannot activate thepiston member 51. As a result, the biasingmember 54 releases its storing force, and biases therear end 422 of thehousing 4 to its original position shown in Figure 4.
• The installer repeats the aforementioned steps until the edges of thecarpet 3 are stretched toward thewall 12, after which a baseboard (not shown) is mounted so as to complete the laying of thecarpet 3.
• It should be noted that the power source in this embodiment is a pneumatic air pump, and operates by introducing high-pressure gas into the receivingspace 41 so as to activate thepiston member 51. However, the power source is not limited to the disclosed embodiment, and can be hydraulic or mechanical in operation, as long as it is able to activate relative movement between thepiston member 51 and thehousing 4.
• Referring to Figures 6 to 8, the second preferred embodiment of thecarpet stretching device 2 according to the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, thefluid supply unit 7 further includes anauxiliary passage 730, and asafety valve assembly 73. Theauxiliary passage 730 includes afirst passage section 731 having two opposite ends connected fluidly and respectively to themain supply passage 711 and thesafety valve assembly 73, and asecond passage section 732 having two opposite ends connected fluidly and respectively to thesafety valve assembly 73 and the first receivingportion 411 of the receivingspace 41 in thehousing 4.
• Thesafety valve assembly 73 is mounted on thecarpet gripping head 6 to control theauxiliary passage 730. Thesafety valve assembly 73 includes afirst port 7331 connected to thefirst passage section 731, asecond port 7332 connected to thesecond passage section 732, athird port 7337 for fluid connection with the atmosphere, afirst valve channel 7333 in fluid communication with the first andsecond ports 7331, 7332 (see arrows in Figure 7), asecond valve channel 7334 in fluid communication with the second andthird ports 7332, 7337 (see arrows in Figure 8), and aplunger 735 that projects downwardly from thecarpet gripping head 6 and that is adapted to contact thecarpet 3.
• When theplunger 735 contacts and presses against thecarpet 3, it pushes avalve disc 733 to move away from avalve seat 7335 so that thefirst valve channel 7333 is opened. The installer at this time may operate themain valve assembly 712 by pressing themain trigger 72 so that the high-pressure gas flows from themain supply passage 711, through thefirst passage section 731, the first andsecond ports 7331, 7332, thesecond passage section 732, and into the first receivingportion 411 of the receivingspace 41 so as to produce relative movement between thehousing 4 and thepiston member 51. As a result, thefront end 421 of thehousing 4 moves away from thepiston member 51, while therear end 422 of thehousing 4 moves toward the piston member 51 (see Figure 5), thereby compressing the biasingmember 54.
• When theplunger 735 is released from contact with thecarpet 3, thevalve disc 733 is biased to move toward thevalve seat 7335 so as to interrupt fluid communication between the first andsecond ports 7331, 7332 so that the high-pressure gas cannot flow from themain supply passage 711 into the receivingportion 411 of thehousing 4. Theplunger 735 is also biased to move away from thevalve disc 733 so as to restore to its original position, as shown in Figure 6. At the same time, the biasingmember 54 in thehousing 4 releases its storing force so as to bias therear end 422 of thehousing 4 away from thepiston member 51 and back to its original position (see Figure 6) . When therear end 422 of thehousing 4 moves gradually away from thepiston member 51, the high-pressure gas is forced out of the first receivingportion 411 to flow through thesecond passage section 732, thesecond port 7332, thesecond valve channel 7334, and thethird port 7337 to the atmosphere.
• It should be noted that thesafety valve assembly 73 permits through theauxiliary passage 730 supply of the high-pressure gas to thehousing 4 from themain supply passage 711 when thesafety valve assembly 73 is activated by pressing of theplunger 735 against thecarpet 3. When theplunger 735 is removed from contact with thecarpet 3, even if themain trigger 72 is accidentally pressed by the installer, the high-pressure gas cannot enter the first receivingportion 411 of thehousing 4, thereby preventing sudden and undesired relative movement between thehousing 4 and thepiston member 51, which may be dangerous.
• Referring to Figure 9, in combination with Figure 6, thepiston unit 5 of this embodiment further includes a stroke adj ustmentmember 524 extending threadedly into thepiston rod 52 opposite to theinsert rod 53. Thestroke adjustment member 524 has arear abutment end 525. Theinsert rod 53 abuts against therear abutment end 525 when therear end 422 of thehousing 4 moves toward thepiston member 51.
• When the power source is not activated, therear abutment end 525 of thestroke adjustment member 524 is spaced apart from theinsert rod 53. When the power source is activated, however, therear end 422 of thehousing 4 together with theinsert rod 53 move relative to thepiston member 51 until theinsert rod 53 abuts against therear abutment end 525, as shown in Figure 9. Since theinsert rod 53 cannot move further after abutting against therear abutment end 525 of thestroke adjustment member 524, thecarpet gripping head 6 that is connected to thehousing 4 also stops from moving forward so that stretching of thecarpet 3 discontinued. Hence, thecarpet 3 may be stretched to a predetermined position. The distance that thecarpet gripping head 6 can move may be adjusted through thestroke adjustment member 524.
• Thus, by adjusting the length of thestroke adjustment member 524 that extends into thepiston rod 52, thecarpet 3 can be stretched to a desired extent. When thecarpet 3 is to be stretched to a large extent, the depth of thestroke adjustment member 524 in thepiston rod 52 should be reduced so that a large distance is provided between therear abutment end 525 and theinsert rod 53, and thecarpet gripping head 6 is permitted to advance a large distance. When the degree of stretching thecarpet 3 need not be large, thestroke adjustment member 524 should be threaded deeply into thepiston rod 52 so that the distance between therear abutment end 525 and theinsert rod 53 is small, thereby permitting thecarpet gripping head 6 to advance a smaller distance than when desiring more significant stretching of thecarpet 3.
• From the aforementioned description of the preferred embodiments of thecarpet stretching device 2 of the present invention, it is apparent that thecarpet stretching device 2 has the following advantages:
1. 1. Since the stretching operation of thecarpet 3 is achieved by operating themain valve assembly 712, which permits the power source to effect relative movement between thehousing 4 and thepiston member 51, when the pin-holdingseat 612 is pierced into thecarpet 3, the installer simply grasps thehandgrip 71, and operates themain valve assembly 712 so that thecarpet 3 is stretched by thecarpet gripping head 6 toward thewall 12. This reduces the workload of the installer. Furthermore, since the stretching operation of thecarpet 3 is achieved by activating thepiston member 51 through the power source, thehousing 4 can move rapidly relative to thepiston member 51, which results in quick stretching of thecarpet 3, thereby minimizing the time required to install thecarpet 3.
2. 2. Through the presence of thesafety valve assembly 73 to control theauxiliary passage 730, when thesafety valve assembly 73 is not operated, the power source cannot be activated by themain valve assembly 712, even if themain trigger 72 is accidentally pressed. Therefore, thecarpet stretching device 2 of the present invention is safe to use.
3. 3. Through the presence of thestroke adjustment member 524, the installer can perform on-site adjustment of the amount of stretching thecarpet 3. Thus, there is no need to purchase multiple carpet stretching devices with differing carpet-stretching levels.

Claims (10)

1. A carpet stretching device (2)characterized by:

   a housing (4) having a front end (421), a rear end (422), and a receiving space (41) between said front and rear ends (421, 422);

   a piston unit (5) including a piston member (51) disposed in said receiving space (41) for moving relative to said housing (4), a piston rod (52) extending out of said housing (4) through said front end (421), and a biasing member (54) provided between said rear end (422) of said housing (4) and said piston member (51);

   a carpet gripping head (6) connected to said housing (4);

   a fluid supply unit (7) connected to said housing (4); and

   an anchor member (522) attached to a front end (521) of said piston rod (52) in front of said carpet gripping head (6).
2. The carpet stretching device (2) as claimed in Claim 1, furthercharacterized by a handgrip (71) connected to said housing (4), said fluid supply unit (7) including a main supply passage (711) provided in said handgrip (71), a main valve assembly (712) provided in said handgrip (71) to control said main supply passage (711), and a main trigger (72) connected to said main valve assembly (712).
3. The carpet stretching device (2) as claimed in Claim 1,characterized in that said carpet gripping head (6) includes a connecting portion (611) connected detachably to said front end (421) of said housing (4) .
4. The carpet stretching device (2) as claimed in Claim 1, furthercharacterized by a knee-applying cushion member (8) provided on said rear end (422) of said housing (4).
5. The carpet stretching device (2) as claimed in Claim 1,characterized in that said piston unit (5) further includes an insert rod (53) having two ends connected respectively to said piston rod (52) and said rear end (422) of said housing (4), said biasing member (54) including a coiled spring extending around said insert rod (53), said insert rod (53) extending into said piston rod (52) and having a hexagonal cross-section to prevent rotation of said piston rod (52).
6. The carpet stretching device (2) as claimed in Claim 2,characterized in that said fluid supply unit (7) further includes an auxiliary passage (730) connected fluidly to said main supply passage (711) and said receiving space (41), and a safety valve assembly (73) provided for controlling said auxiliary passage (730), said safety valve assembly (73) permitting said auxiliary passage (730) to supply fluid to said housing (4) from said main supply passage (711) only when said safety valve assembly (73) is activated.
7. The carpet stretching device (2) as claimed in Claim 1,characterized in that said piston unit (5) further has a stroke adjustment member (524) extending into said piston rod (52) opposite to said insert rod (53), said stroke adjustment member (524) having a rear abutment end (525), said insert rod (53) abutting against said rear abutment end (525) when said piston member (51) moves rearwardly.
8. A carpet stretching device (2)characterized by:

   a housing (4);

   a handgrip (71) connected to said housing (4);

   a piston unit (5) including a piston member (51) movably disposed within said housing (4), and a piston rod (52) connected to said piston member (51) and extending out of said housing (4);

   a carpet gripping head (6) connected to one of said housing (4) and said piston rod (52);

   an anchor member (522) attached to the other one of said housing (4) and said piston rod (52); and

   a fluid supply unit (7) which includes

   a main supply passage (711) provided in said handgrip (71);

   a main valve assembly (712) provided in said handgrip (71) and controlling said main supply passage (711);

   an auxiliary passage (730) connected fluidly to said main supply passage (711) and said housing (4); and

   a safety valve assembly (73) for controlling said auxiliary passage (730).
9. The carpet stretching device (2) as claimed in Claim 8,characterized in that said auxiliary passage (730) includes a first passage section (731) which is connected fluidly to said main supply passage (711) and said safety valve assembly (73), and a second passage section (732) which is connected fluidly to said safety valve assembly (73) and said housing (4) .
10. The carpet stretching device (2) as claimed in Claim 9,characterized in that said safety valve assembly (73) includes a first port (7331) connected to said first passage section (731), a second port (7332) connected to said second passage section (732), a third port (7337) for fluid connection with the atmosphere, a first valve channel (7333) in fluid communication with said first and second ports (7331, 7332), and a second valve channel (7334) in fluid communication with said second port (7332) and said third port (7337).

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