靠背輪聯軸器用來將不同機構中的主動軸和從動軸牢固地聯接起來一同旋轉，并傳遞運動和扭矩的機械部件。有時也用以聯接軸與其他零件（如齒輪、帶輪等）。

靠背輪常由兩半合成，分別用鍵或緊配合等聯接，緊固在兩軸端，再通過某種方式將兩半聯接起來。

靠背輪聯軸器可兼有補償兩軸之間由于制造安裝不精確、工作時的變形或熱膨脹等原因所發生的偏移（包括軸向偏移、徑向偏移、角偏移或綜合偏移）；以及緩和沖擊、吸振。

靠背輪為俗稱，專業叫法為聯軸器以及法蘭，用于機械設備的連接。

柱銷聯軸器是利用一端套有彈性套（橡膠材料）的柱銷，裝在兩半聯軸器凸緣孔中，以實現兩半聯軸器的聯接。

彈性柱銷聯軸器是一種結構簡單制造容易，無需潤滑，裝拆彈性柱銷便捷的傳動基礎件，利用兩個帶法蘭孔的半聯和置于起重的非金屬彈性柱銷來傳遞扭矩，適用于中低速和中低扭矩場合。

彈性柱銷齒式聯軸器采用非金屬彈性柱銷和兩個帶齒形半聯以及一個外圈的齒形套環設計，利用非金屬彈性的變形來傳遞扭矩同時緩沖減震，補償角向位移。

彈性套柱銷聯軸器設計簡單巧妙，適用性較廣的聯軸器，利用帶彈性套的柱銷聯接兩個帶銷孔的半聯，實現扭矩傳遞的同時兼具較大的角向補償，同時減震緩沖性能良好，可以用在速度較快的場合，無需潤滑，銷套更換便捷。

The pin gear coupling is designed with non-metallic flexible pin, two toothed semi-couplings and a toothed sleeve ring with an outer ring. It uses non-metallic flexible deformation to transfer torque and cushion shock and compensate angular displacement. The flexible pin coupling is a basic transmission parts that has simple structure, needs no lubrication, and is easy to manufacture, install and disassemble the flexible pin. It uses two semi-couplings with flange holes and a non-metallic flexible pin for crane to transmit torque, suitable for low-to-medium speed and low-to-medium torque occasions. The design of the elastic sleeve pin coupling is simple and clever in design and has wide applicability. It uses the pin with elastic sleeve to connect two semi-couplings with pin holes to realize torque transmission and larger angular compensation. At the same time, Pin and bush couplings has good shock absorption and buffering performance, which can be used in high-speed occasions without lubrication and requiring easy pin sleeve replacement.